Oxygen and Nitrogen Effects on MC Carbide in K465 Nickel-Base Superalloy
Catalytic Conversion of Carbon Dioxide into Fuel
Catalytic Conversion of Carbon Dioxideinto FuelThe world is facing a major challenge in reducing the amount of greenhouse gases released into the atmosphere. One of the main culprits is carbon dioxide (CO2), which is primarily produced from the burning of fossil fuels. In recent years, researchers have been working on developing new ways to convert CO2 into useful products, such as fuels and chemicals. One of the most promising technologies is catalytic conversion.Catalysts are substances that speed up chemical reactions without being consumed in the process. In the case of CO2 conversion, catalysts can help to break down the molecule and reassemble its atoms into a new product. There are many different types of catalysts that can be used, depending on the desired product and reaction conditions.One of the main challenges of CO2 conversion is that the molecule is very stable. This means that a lot of energy is needed to break the carbon-oxygen bond and create new bonds with other atoms. Catalysts can help to lower the energy barrier for these reactions, making them more efficient and sustainable.There are several different pathways for catalytic CO2 conversion. One of the most widely studied reactions is the reduction of CO2 to formate (HCOO-) or other oxygenates, such as methanol and ethanol. This reaction typically requires a reducing agent, such as hydrogen, and a metal catalyst, such as copper. The process can be optimized by controlling the reaction conditions, such as temperature, pressure, and pH.Another promising pathway is the conversion of CO2 to hydrocarbons, such as methane and ethylene. This reaction involves the activation of CO2 to form a reactive intermediate, which can then react with a hydrogen source to form the desired product. Catalysts that have been studied for this reaction include metal oxides, such as ceria and zirconia, and metal nanoparticles, such as ruthenium and iron.One of the key advantages of catalytic CO2 conversion is that it can be integrated with renewable energy sources, such as solar and wind power. In this scenario, excess energy can be used to drive the reactions and produce fuels that can be stored and used when needed. This can help to improve the overall efficiency and sustainability of the energy system.Another advantage is that catalytic CO2 conversion can help to reduce the carbon footprint of industry. By capturing CO2 emissions and converting them into useful products, companies can reduce their reliance on fossil fuels and minimize their environmental impact. This can also help to create new business opportunities and drive innovation in the field.Despite the many benefits, there are still some challenges that need to be addressed when it comes to catalytic CO2 conversion. One of the main issues is scalability. Many of the reactions that have been studied are still in the laboratory stage and have not been scaled up to industrial levels. This requires significant investment in terms of equipment, infrastructure, and supply chain management.Another challenge is the cost of the catalysts. Many of the metals and other materials that are used as catalysts can be expensive and difficult to obtain. This can affect the overall economics of the process and make it less competitive compared to other carbon capture and storage (CCS) technologies.In conclusion, catalytic conversion of CO2 into fuel and other valuable products has the potential to be a game-changer in the fight against climate change. By using catalysts to accelerate reactions and lower energy requirements, the process can be made more efficient and sustainable. With further research and investment, we can unlock the full potential of this technology and create a cleaner, greener future.。
七年级全球挑战与社会责任英语阅读理解30题
七年级全球挑战与社会责任英语阅读理解30题1<背景文章>Global warming is a serious problem that the world is facing. It refers to the long-term increase in the average temperature of the Earth's climate system. The main cause of global warming is the increase in greenhouse gases, such as carbon dioxide, methane, and nitrous oxide. These gases trap heat in the atmosphere and cause the temperature to rise.One of the most visible effects of global warming is the melting of glaciers and ice caps. This leads to rising sea levels, which can cause flooding in coastal areas. Global warming also causes changes in weather patterns, such as more extreme heat waves, droughts, and storms.We need to take action to reduce global warming. We can do this by reducing our use of fossil fuels, such as coal, oil, and gas. We can also plant more trees, which absorb carbon dioxide from the atmosphere.1. What is global warming?A. A short-term increase in temperature.B. A long-term increase in the average temperature of the Earth's climate system.C. A decrease in temperature.D. No change in temperature.答案：B。
乙酸蒸汽催化重整制氢的研究进展
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第5期·1658·化 工 进展乙酸蒸汽催化重整制氢的研究进展王东旭1，肖显斌2，李文艳1（1华北电力大学能源动力与机械工程学院，北京 102206；2华北电力大学生物质发电成套设备国家工程实验室，北京 102206）摘要：通过生物油蒸汽重整制备氢气可以减少环境污染，降低对化石燃料的依赖，是一种极具潜力的制氢途径。
乙酸是生物油的主要成分之一，常作为模型化合物进行研究。
镍基催化剂是乙酸蒸汽重整过程中常用的催化剂，但容易因积炭失去活性，降低了制氢过程的经济性。
本文首先分析了影响乙酸蒸汽重整制氢过程的各种因素，阐述了在这一过程中镍基催化剂的积炭原理，讨论了优化镍基催化剂的方法，包括优化催化剂的预处理过程、添加助剂和选择合适的载体，最后对乙酸蒸汽重整制氢的热力学分析研究进展进行了总结。
未来应重点研究多种助剂复合使用时对镍基催化剂积炭与活性的影响，分析多种助剂的协同作用机理，得到一种高活性、高抗积炭能力的用于生物油蒸汽重整制氢的镍基催化剂。
关键词：生物油；乙酸；制氢；催化剂；热力学中图分类号：TK6 文献标志码：A 文章编号：1000–6613（2017）05–1658–08 DOI ：10.16085/j.issn.1000-6613.2017.05.014A review of literatures on catalytic steam reforming of acetic acid forhydrogen productionWANG Dongxu 1，XIAO Xianbin 2，LI Wenyan 1（1 School of Energy ，Power and Mechanical Engineering ，North China Electric Power University ，Beijing 102206，China ；2 National Engineering Laboratory for Biomass Power Generation Equipment ，North China Electric PowerUniversity ，Beijing 102206，China ）Abstract ：Hydrogen production via steam reforming of bio-oil ，a potential way to produce hydrogen ， can reduce environmental pollution and dependence on fossil fuels. Acetic acid is one of the main components of bio-oil and is often selected as a model compound. Nickel-based catalyst is widely used in the steam reforming of acetic acid ，but it deactivates fast due to the carbon deposition. In this paper ，the affecting factors for the steam reforming of acetic acid are analyzed. The coking mechanism of nickel-based catalyst in this process is illustrated. Optimization methods for nickel-baed catalyst are discussed ，including optimizing the pretreatment process ，adding promoters ，and choosing appropriate catalyst supports. Research progresses in the thermodynamics analyses for steaming reforming of acetic acid are summarized. Further studies should be focused on the effects of a combination of a variety of promoters on carbon deposition. Catalytic activity and the synergy mechanism should be analyzed to produce a novel nickel-based catalyst with high activity ，high resistance to caborn deposition for hydrogen production via steam reforming of bio-oil. Key words ：bio-oil ；acetic acid ；hydrogen production ；catalyst ；thermodynamics第一作者：王东旭（1994—），男，硕士研究生，从事生物质能利用技术研究。
Microbial processes in the nitrogen cycle
Microbial processes in the nitrogencycleThe nitrogen cycle is a crucial process in the environment, as it involves the transformation and circulation of nitrogen in various forms. Microbial processes play a significant role in the nitrogen cycle, as they are responsible for carrying out key transformations of nitrogen compounds. These processes include nitrogen fixation, nitrification, denitrification, and ammonification, all of which are facilitated by different groups of microorganisms. Understanding the microbial processes in the nitrogen cycle is essential for comprehending the overall functioning of ecosystems and their sustainability. One of the most important microbial processes in the nitrogen cycle is nitrogen fixation, which is the conversion of atmospheric nitrogen (N2) into ammonia (NH3) or related compounds. This process is primarily carried out by nitrogen-fixing bacteria such as Rhizobium, Azotobacter, and cyanobacteria. These bacteria form symbiotic relationships with certain plants, such as legumes, where they reside in nodules on the plant roots and convert atmospheric nitrogen into a form that the plants can use for their growth and development. This process is vital for maintaining the nitrogen balance in the soil and providing a source of nitrogen for the growth of plants. Nitrification is another crucial microbial process in the nitrogen cycle, involving the oxidation of ammonium (NH4 ) to nitrite (NO2-) and then to nitrate (NO3-). This process is carried out by nitrifying bacteria such as Nitrosomonas and Nitrobacter. Nitrification plays a significant role in making nitrogen available to plants, as nitrate is a form of nitrogen that plants can readily uptake and utilize for their growth. Additionally, nitrification also helps in removing excess ammonium from the soil, preventing it from leaching into water bodies and causing pollution. On the other hand, denitrification is the microbial process responsible for the reduction of nitrate (NO3-) to nitrogen gas (N2) or nitrous oxide (N2O) by denitrifying bacteria such as Pseudomonas and Paracoccus. This process is essential for returning nitrogen to the atmosphere and completing the nitrogen cycle. Denitrification occurs in oxygen-deprived environments such as waterlogged soils and sediments, where these bacteria usenitrate as an alternative electron acceptor for respiration. This process not only helps in maintaining the balance of nitrogen in the environment but also has implications for greenhouse gas emissions, as nitrous oxide is a potent greenhouse gas. Ammonification is another microbial process in the nitrogen cycle, where organic nitrogen from dead plants, animals, and waste products is converted into ammonium by ammonifying bacteria and fungi. This process is crucial for the recycling of nitrogen in ecosystems, as it converts organic nitrogen into an inorganic form that can be utilized by plants and other organisms. Ammonification is a key step in the decomposition of organic matter, and it contributes to the fertility of soils by releasing ammonium, which can be further transformed through nitrification and taken up by plants. In conclusion, microbial processes play a fundamental role in the nitrogen cycle, as they are responsible for carrying out key transformations of nitrogen compounds. These processes, including nitrogen fixation, nitrification, denitrification, and ammonification, are facilitated by different groups of microorganisms and are essential for the functioning and sustainability of ecosystems. Understanding the microbial processes in the nitrogen cycle is crucial for managing and conserving the nitrogen balance in the environment, as well as for addressing issues such as nutrient pollution and greenhouse gas emissions. Overall, the intricate interactions between microorganisms and nitrogen compounds highlight the importance of microbial processes in maintaining the balance of nitrogen in the environment.。
全氧烧嘴-速焰英国
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Industrial Burners Handbook
21.1 INTRODUCTION
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21.2.1.1 High Flame Temperature and Heat Transfer High adiabatic flame temperature and high heat release rate and transfer are the main benefits for which traditional applications of oxy-fuel burners were developed. Welding with an oxy-acetylene flame, flame polishing of glass surfaces, and oxygen cutting of steel plates are some of examples of applications that take advantage of these oxy-fuel flame characteristics. 21.2.1.2 Fuel Savings The use of oxygen in a heating process eliminates the nitrogen introduced with combustion air from the process and hence eliminates the energy required to heat the nitrogen from inlet temperature to outlet temperature. For high-temperature processes (>2200°F or 1200°C) with no heat recovery, fuel savings when using oxygen can exceed 50%. As heat recovery is employed with the air combustion system, the savings achievable when switching to oxy-fuel combustion are reduced. A simple heat and mass balance on the furnace under each operating condition can provide accurate
讲座6末端淬火法The Jominy end quench test to measure the
Jominy end quench test 末端淬火法
• The test sample is a cylinder with a length of 102 mm (4 inches) and a diameter of 25.4 mm (1 inch).
Jominy test specimen
末端淬火法 确定钢的淬透性
The Jominy end quench test to measure the hardenability of a steel
Hardenability and the Jominy test.
• The Jominy end quench test is the standard method for measuring the hardenability of steels, which is a measure of the capacity of the steel to harden in depth under a given set of conditions.
• The round specimen is then ground flat along its length to a depth of 0.38 mm (15 thousandths of an inch) to remove decarburised material. The hardness is measured at intervals from the quenched end. The interval is typically 1.5 mm for alloy steels and 0.75 mm for carbon steels.
Jominy test machine
氧传质的英语
氧传质的英语The Importance of Oxygen Transfer in Biological ProcessesOxygen transfer is a fundamental process in various biological systems, playing a crucial role in sustaining life and enabling essential metabolic reactions. The efficient transfer of oxygen is crucial for the survival and functioning of organisms, as it facilitates the conversion of energy-rich molecules into usable forms of energy. In this essay, we will explore the significance of oxygen transfer, its mechanisms, and its applications in different biological contexts.Oxygen is a vital element for the majority of living organisms, as it serves as the final electron acceptor in the process of cellular respiration. This process, also known as aerobic respiration, is the primary means by which organisms convert the energy stored in organic molecules, such as glucose, into a more usable form of energy, known as adenosine triphosphate (ATP). During this process, oxygen is reduced to water, and the energy released is used to drive the synthesis of ATP, which is the universal energy currency of cells.The transfer of oxygen from the environment to the cells within an organism is a complex and multifaceted process. In multicellularorganisms, such as humans, oxygen is first transported from the external environment through the respiratory system, where it is absorbed into the bloodstream. The oxygen-rich blood then circulates throughout the body, delivering the oxygen to the various tissues and organs that require it for their metabolic activities.At the cellular level, oxygen must be able to diffuse from the bloodstream into the individual cells, where it can be utilized in the mitochondria, the power-generating organelles within the cells. This process of oxygen transfer is facilitated by the presence of specialized proteins, such as hemoglobin, which bind to oxygen molecules and transport them efficiently throughout the body.The efficiency of oxygen transfer is crucial for the proper functioning of various biological processes. In the context of cellular respiration, the rate of oxygen transfer can directly impact the rate of ATP production, which is essential for powering a wide range of cellular activities, from muscle contraction to neural signaling.Moreover, the efficient transfer of oxygen is also critical for the maintenance of tissue health and the prevention of hypoxic conditions, where tissues are deprived of sufficient oxygen. Hypoxia can lead to a variety of adverse effects, such as tissue damage, organ dysfunction, and even cell death. Therefore, understanding and optimizing the mechanisms of oxygen transfer is of utmostimportance in various medical and biological applications.One area where the understanding of oxygen transfer is particularly relevant is in the field of respiratory physiology and medicine. Conditions such as asthma, chronic obstructive pulmonary disease (COPD), and lung cancer can impair the ability of the respiratory system to effectively transfer oxygen, leading to various health complications. In these cases, medical interventions, such as supplemental oxygen therapy or mechanical ventilation, may be necessary to ensure adequate oxygen delivery to the tissues.Similarly, in the field of exercise physiology, the efficiency of oxygen transfer is a critical factor in determining an individual's physical performance and endurance. Elite athletes often undergo training regimens and interventions designed to enhance their oxygen delivery and utilization, as this can directly impact their ability to sustain high levels of physical activity.Beyond these clinical and physiological applications, the principles of oxygen transfer also have important implications in the field of biotechnology and environmental engineering. In the context of wastewater treatment, for example, the efficient transfer of oxygen is essential for the growth and activity of aerobic microorganisms, which are responsible for the degradation of organic matter and the removal of various pollutants.Similarly, in the production of biofuels and other valuable biochemicals, the optimization of oxygen transfer can play a crucial role in enhancing the productivity and efficiency of microbial fermentation processes. By understanding the mechanisms of oxygen transfer, researchers and engineers can design more effective bioreactors and cultivation systems, leading to improved yields and reduced production costs.In conclusion, the importance of oxygen transfer in biological processes cannot be overstated. From the cellular level to the organismal and ecosystem scales, the efficient transfer of oxygen is a fundamental requirement for the survival and thriving of living organisms. By continuing to expand our understanding of the mechanisms and applications of oxygen transfer, we can unlock new opportunities for advancements in various fields, including medicine, biotechnology, and environmental sustainability.。
低碳制取氧气英文作文
低碳制取氧气英文作文英文：Low-carbon production of oxygen involves the use of environmentally friendly methods to extract oxygen from the air. One such method is the use of a pressure swing adsorption (PSA) system. This system utilizes activated carbon or zeolite to selectively adsorb nitrogen and other gases, leaving behind pure oxygen.Another method is the use of membrane technology, which involves the use of a semi-permeable membrane to separate oxygen from other gases. This method is particularly useful for small-scale production.Both of these methods are low-carbon as they do not require the use of fossil fuels, which are a major source of greenhouse gas emissions. By using these methods, we can reduce our carbon footprint and contribute to a more sustainable future.中文：低碳制取氧气涉及使用环保的方法从空气中提取氧气。
其中一种方法是使用压力摆动吸附（PSA）系统。
高铁血红素对盐胁迫下小麦根部生长_省略_的缓解和根尖中离子微域分布的影响_胡冰
植物生理学通讯 第44卷 第5期，2008年10月865高铁血红素对盐胁迫下小麦根部生长受抑的缓解和根尖中离子微域分布的影响胡冰1, 贺子义1, 林国庆1, 谢彦杰2, 齐继艳2, 江丹君3, 沈文飚2, 黄丽琴3,*南京农业大学1生命科学实验中心, 南京农业大学-天美电镜合作示范实验室, 2生命科学学院, 3理学院, 南京210095提要: 小麦幼苗经不同浓度NaCl 处理1 d 再转入Hoagland 培养液中培养2 d 后, 浓度相对较低(100和200 mmol·L -1)的NaCl 处理的幼苗根部生长抑制可以恢复, 而浓度相对较高(500 mmol·L -1)的NaCl 处理的则不能恢复; 预先以高铁血红素(5 µmol·L -1)处理1 d 就可以缓解随后200 mmol·L -1 NaCl 处理引起的小麦根部生长受抑。
X 射线电子探针检测元素分布的结果表明, 高铁血红素还可缓解由NaCl 胁迫导致的小麦苗根尖表皮、皮层和中柱细胞中的K +流失, 并可提高根系中K +/Na +比, 从而维持根部的离子稳态。
关键词: 高铁血红素; 盐胁迫; 小麦; 离子微域分布; X 射线电子探针Effects of Hematin on Mitigation of Growth Inhibition and Ion Micro-distribu-tion of Wheat Roots under Salt StressHU Bing 1, HE Zi-Yi 1, LIN Guo-Qing 1, XIE Yan-Jie 2, QI Ji-Yan 2, JIANG Dan-Jun 3, SHEN Wen-Biao 2, HUANG Li-Qin 3,*1Laboratory Center of Life Sciences, Nanjing Agricultural University Cooperative Demonstration Laboratory of HITACHI Elec-tronic Microscope Technique, 2College of Life Sciences, 3College of Sciences, Nanjing Agricultural University, Nanjing 210095,ChinaAbstract: Wheat seedlings subjected to salt stress for 1 d were then transferred to Hoagland solution for another 2 d, the root growth inhibition caused by low concentration of salt stress (100 and 200 mmol·L -1 NaCl)could be recovered, while high concentration (500 mmol·L -1) NaCl exhibited the opposite effect. Furthermore,pretreatment with 5 µmol·L -1 hematin attenuated the root growth inhibition elicited by 200 mmol·L -1 NaCl stress.By using X-ray electron probe analysis, we also discovered that pretreatment of hematin alleviated salinity-induced K + outfluxes in the epidermis, cortex and stele of the root cells, thus K +/Na + increased and the ion homeostasis could be reestablished.Key words: hematin; salt stress; wheat (Triticum aestivum ); ion micro-distribution; X-ray electron probe收稿2008-05-07修定2008-08-25资助国家自然科学基金(30671248)、国家基础科学人才培养基金(J0730647)和南京农业大学SRT 项目(0706A01和0712A08)。
Biochar volatile matter content effects on plant growth and nitrogen
BIOCHAR VOLATILE MATTER CONTENT EFFECTS ON PLANT GROWTH AND NITROGEN TRANSFORMATIONS IN A TROPICALSOILJonathan L. Deenik, A.T. McClellan and G. UeharaDepartment of Tropical Plant and Soil Sciences, University of Hawaii, Honolulu, HI ABSTRACTBiochars made from modern pyrolysis methods have attracted widespread attention as potential soil amendments with agronomic value. A series of greenhouse experiments and laboratory incubations were conducted to assess the effects of biochar volatile matter (VM) content on plant growth, nitrogen (N) transformations, and microbial activities in an acid tropical soil. High VM biochar inhibited plant growth and reduced N uptake with and without the addition of fertilizers. Low VM charcoal supplemented with fertilizers improved plant growth compared with the fertilizer alone. The laboratory experiments showed that high VM biochar increased soil respiration and immobilized considerable quantities of inorganic N. This research shows that biochar with high VM content may not be a suitable soil amendment in the short-term. INTRODUCTIONThe use of biochar as a soil amendment is modeled on the C-rich anthropogenic soils known as “Terra Preta do Indio” (Indian black earth) found in Amazonia and associated with habitation sites of pre-contact Amerindian populations dating as far back as 7,000 cal yr BP (Glaser, 2007). The defining characteristic of Terra Preta soils is the presence of large quantities of charcoal in the soil organic matter to depths of 1 m or greater (Glaser et al., 2000; Sombroek et al., 1993). These soils are remarkable because they have remained fertile and enriched in soil C compared with adjacent forest soils despite centuries of cultivation.Recent efforts to replicate the “Terra Preta” phenomenon using biochars created from modern pyrolysis techniques show that charcoal additions can have an ameliorating effect on highly weathered, infertile tropical soils by increasing CEC and plant nutrient supply, reducing soil acidity and aluminum toxicity, and improving fertilizer efficiency due to reduced nutrient leaching (Glaser at al., 2002; Lehmann et al., 2003). Plant growth response to charcoal amended soils has been variable with both negative and positive results reported in the scientific literature (Glaser at al., 2002). Several studies have reported that plant growth responses are largest when charcoal and fertilizers are combined suggesting a synergistic relationship (Chan et al., 2007; Lehmann et al., 2003; Steiner et al., 2007). Gundale and Deluca (2007) observed that laboratory produced charcoal from ponderosa pine and Douglas-fir had a negative effect on plant growth whereas the same charcoal created from wildfires showed a positive effect on plant growth. The authors speculated that the low temperature charring method used to create the charcoal in the laboratory either created toxic compounds that inhibited plant growth or acted as a source of labile carbon (C) stimulating microbial growth and N immobilization. The objectives of the present research were to determine the effects of charcoal volatile matter content on plant growth and N transformations in a tropical acid soil. We hypothesized that biochar created at low temperatures with high VM would increase microbial activity resulting in a decrease in plant available N due to immobilization.MATERIALS AND METHODSTwo greenhouse bioassays and two laboratory incubations were conducted to test the effects of biochar VM content on plant growth and N transformations. The soil was an infertile, acid Leilehua series (very-fine, ferruginous, isothermic, ustic kanhaplohumults) collected from the 30-80 cm depth at the Waiawa Correctional Facility, Mililani, Oahu Island (N21°26’53”, W157° 57’ 52”). The charcoal feedstock used in our experiments was macadamia nut shells. The charcoal was made using a flash carbonization process developed at the Natural Energy Institute at the University of Hawaii (Antal et al., 2003). Selected chemical properties of the soil and biochars used in the different experiments are presented in Table 1. Total C and N content of the biochars were determined by dry combustion on a LECO CN-2000. Biochar pH was measure in 1:1 slurry of charcoal to deionized water. Base cations were extracted with 1M ammonium acetate at pH 7 and Al+++ was extracted with 1M KCl and measured in solution by inductive coupled plasma spectrophotometer. The effective cation exchange capacity (ECEC) of the biochars and soil was determined by summing the exchangeable cations.Table 1. Selected chemical properties of the Leilehua soil, and the biochars used in the greenhouse and laboratory experiments (LVM = low VM content and HVM = high VM content).VM Ash OC TN pH P K Ca Mg Na Al ECEC%kg-1 cmol c kg-1mgSoilLeilehua 4.28 0.12 4.70 2.22 0.09 0.720.520.29 1.61 3.22 CharcoalLVM6.30 4.18 88.7 0.45 8.1617.2 1.25 3.7 0.31 0.011 22.5MacNutHVM22.5 3.33 85.2 0.45 5.7218.5 0.740.7 0.15 0.032 20.2MacNutIn the first greenhouse bioassay we imposed five treatments consisting of a control (unamended soil), soil+lime, soil+biochar, soil+lime+NPK and soil+biochar+lime+NPK arranged in randomized block design with four replications. The biochar contained 22.5 % VM and was considered a high VM biochar. Biochar was applied to achieve 10% (w/w), lime to achieve 2 T ha-1, N as NH4NO3 at a rate of 200 mg N kg-1, P as Ca(H2PO4)2 to achieve a rate of 750 mg P kg-1, K and Mg were added in solution at a rate equivalent to 200 and 100 kg ha-1 respectively, and the micronutrients Cu, Mn, and Zn were added in solution at a rate of 10 kg ha-1. We used corn (Zea mays, var super sweet #9) as the test crop. Eight corn seeds were planted into each pot and thinned to four plants after emergence. The second greenhouse bioassay consisted of five treatments (unamended soil, soil+lime+NPK, soil + high VM biochar, soil + low VM biochar, soil + low VM biochar + NPK) installed in a complete randomized block design with four replicates. Lime and fertilizers were applied at the same rates as in the first experiment and corn was the test crop. At harvest time, above-ground biomass was cut at the soil surface dried at 70°C for 72 hours, weighed and tissue analyzed for nutrient content according to standard procedures (Hue et al., 2000).We conducted two laboratory studies to evaluate the effect of biochar VM content on net N mineralization rates and on CO2 respiration. Both experiments consisted of three treatments, a control (untreated Leilehua soil) and the Leilehua soil amended with high and low VM macadamia nut biochar applied at the same rate as in the greenhouse experiment. For the Nstudy, the biochar was mixed thoroughly with 50 g (oven dry equivalent) of soil followed by the addition of the appropriate volume of deionized water required to bring the soil to 75% of water holding capacity. The soils were placed in 100 mL beakers, weighed at the outset of the incubation, covered with perforated parafilm, and incubated at constant temperature (28°C) and moisture. Soils were sampled and analyzed for inorganic N, protease activity, and K 2SO 4 extractable organic C and TN after 2, 7, and 14 days. The soluble C fraction of the biochar was determined by shaking 3 g of biochar in 30 mL deionized water for 1 hour and filtering through a 45 μm nylon membrane. For the CO 2 respiration study, we used the alkali adsorption method where 50 g of treated and untreated soils and 50 ml of 0.05 M NaOH were sealed in airtight 1 L mason jars and incubated at 28°C for 14 days (Alef, 1995). The beaker containing the NaOH solution was removed from the mason jar at 48 hour intervals and titrated with 0.05 M HCl following the addition of 0.5 M BaCl 2. Four mason jars with the 0.05 M NaOH solution, but without soil were used as controls.RESULTS AND DISCUSSIONThe high VM biochar used in the first greenhouse bioassay had a significant negative effect on corn growth compared to the control (Fig. 1). Amending the soil with conventional inorganic fertilizers (lime+NPK) produced significant increases in corn growth, but the beneficialcombining charcoal with the fertilizer therewas an approximately 50% decline in corn showed very low N, P and K concentrations in the tissue (data not shown). Tissue N and fertilizers significantly increased tissue N, P, and K concentrations and the accompanying significant rise in dry matter production indicated that the Leilehua soil was severely deficient in N, P, and K. The biochar in combination with fertilizers, however,significantly decreased tissue N, P, and K concentrations compared to the fertilizer control treatment. Our observations were in disagreement with a recent greenhouse experiment reporting that biochar significantly improved N fertilizer use efficiency by radish plants (Chan et al., 2007). We speculated that the relatively high VM content of the biochar used in this experiment may have played a role in inhibiting corn growth. Figure 1. Treatment effects on above ground corn dry matter production in an infertile Leilehua soil amended with high VM biochar and fertilizer (S = soil, S+C = soil + biochar, S+L = soil + lime, S+F+L = soil + NPK + lime, S+C+F = soil + biochar + NPK).The results of the second greenhouse experiment showed that biochar VM content had significant effects on plant growth. High VM biochar significantly reduced shoot dry matter compared with the control whereas low VM biochar had no significant effect on dry mattercharcoal treatment than in the high VMcharcoal treatment. The low VM biocharproduction compared with the fertilizeralone treatment. The high VM biochar reduced N uptake by 50% compared withthe control. On the other hand, the low VM biochar did not reduce N uptake intreatment. Although the low VM biochar with fertilizer treatment did not show ashigh an increase in plant growth nor a significant increase in N uptake compared with the fertilizer treatment as in the results reported by Chan and his group(2007), our results provide evidence that the VM content of the biochar is an important factor affecting its agronomic value as a soil amendment. We suspected that high VM charcoal is a source of labile C for soil microorganisms, and the high C:N ratio of the C source stimulated immobilization of the plant available Nin the soil causing N deficiency in the growing plants. A recent experimentreported similar results showing thatcharcoal produced at low temperature(350°C) had a negative effect on plantgrowth (Gundale and DeLuca, 2007), and the researchers speculated that thedecline in plant growth was caused byphenols in the charcoal, which servedas a high C:N carbon source for soilmicroorganisms.Results from the two incubation VM exerts a strong influence on N mineralization and microbial respiration. The untreated soil showedan initial drop in soil NH 4+-N after twodays from 39.4 to 31.7 mg kg -1 followed by a slow increase to 45.3 and 43.4 mg kg -1 after seven Figure 2. Treatment effects on above ground corn dry matter production in an infertile Leilehua soil amended withhigh and low VM biochar and fertilizer (S = soil, HVM = high VM biochar, LVM = low VM biochar). Figure 3. Biochar effects on soil NH 4+-N in a 14 - day incubation.and fourteen days respectively (Fig. 3). The soil amended with high VM biochar, however, showed a dramatic decline in soil NH 4+-N that persisted throughout the fourteen day incubation. The low VM biochar had a much smaller effect on soil NH 4+-N decreasing it to around 30 mg kg -1. In the CO 2 respiration study, the high VM biochar amendment caused a steep increase in respiration reaching a peak at four days followed by a gradual decline through the 12th day (Fig.4). At day 2 and day 6 the high VMbiochar treatment showed a respiration rate threefold higher than the control, which remained at least twice as high as the control throughout the remainder ofrespiration at day 2 followed by a rapiddecline matching the control values bythe eighth day. The relatively high CO 2 dramatic decline in soil NH 4+-Nconcentration observed in the high VM biochar treatment is strong evidence that biomass was an important factor explaining the observed decline in plant growth and N uptake in the high VMbiochar treatments. The high water extractable C content of the high VM biochar (265 mg C kg -1) compared with the low VM biochar (53 mg kg -1) provided a labile source of C fueling the observed stimulation of microbial activity in the high VM treatment. With the high C:N ratio of the biochar, the microbial biomass was forced to scavenge soil N inducing N deficiency in the growing plants.Figure 4. Biochar effects on CO2 respiration in a 12-day incubation.SUMMARYThis research shows that biochar VM content, or the degree of carbonization, can play a critical role in determining its agronomic value as a soil amendment. Our results provide clear evidence that biochars that are high in VM content (i.e., a typical barbecue charcoal) would not be good soil amendments because they can stimulate microbial activity and immobilize plant available N in the short-term. On the other hand, more fully carbonized biochars with lower VM content containing a smaller labile C component have a smaller effect on soil microbial activity and N immobilization. While our research provides one explanation for why some biochars have a negative effect on plant growth, it still remains unclear why low VM biochars in combination with fertilizer appear to have a beneficial effect on plant growth. Despite our findings elucidating the role of VM content in inhibiting N mineralization, research at the field scale is required to truly assess the agronomic value of biochars as soil amendments.REFERENCESAlef, K. 1995. Soil Respiration, p. 214-216, In K. Alef and P. Nannipieri, eds. Methods inapplied soil microbiology and biochemistry. Academic Press, London.Antal, M.J., K. Mochidzuki, and L.S. Paredes. 2003. Flash carbonization of biomass. Industrial & Engineering Chemistry Research 42:3690-3699.Chan, K.Y., L. Van Zwieten, I. Meszaros, A. Downie, and S. Joseph. 2007. Agronomic values of greenwaste biochar as a soil amendment. Australian Journal of Soil Research 45:629-634. Glaser, B. 2007. Prehistorically modified soils of central Amazonia: a model for sustainable agriculture in the twenty-first century. Philosophical Transactions of the Royal Society B-Biological Sciences 362:187-196.Glaser, B., E. Balashov, L. Haumaier, G. Guggenberger, and W. Zech. 2000. Black carbon in density fractions of anthropogenic soils of the Brazilian Amazon region. Organic Geochemistry 31:669-678.Glaser, B., J. Lehmann, and W. Zech. 2002. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal - a review. Biology and Fertility of Soils 35:219-230.Gundale, M.J., and T.H. DeLuca. 2007. Charcoal effects on soil solution chemistry and growth of Koeleria macrantha in the ponderosa pine/Douglas-fir ecosystem. Biology and Fertility of Soils 43:303-311.Hue, N.V., R. Uchida, and M.C. Ho. 2000. Sampling and analysis of soils and plant tissues. pp.23-30, In J. A. S. a. R. S. Uchida, ed. Plant Nutrient Management in Hawaii Soils. College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu. Lehmann, J., J.P. da Silva, C. Steiner, T. Nehls, W. Zech, and B. Glaser. 2003. Nutrient availability and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin: fertilizer, manure and charcoal amendments. Plant and Soil 249:343-357. Sombroek, W.G., F.O. Nachtergaele, and A. Hebel. 1993. Amounts, dynamics and sequestering of carbon in tropical and subtropical soils. Ambio 22:417-426.Steiner, C., W. Teixeira, J. Lehmann, T. Nehls, J. de Macêdo, W. Blum, and W. Zech. 2007.Long term effects of manure, charcoal and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil. Plant and Soil 291:275-290. ACKNOWLEDGEMENTSWe thank Dr. Michael Antal for providing biochar samples along with proximate analysis data and Yudai Tsumiyoshi and Jocelyn Liu for assistance with laboratory analysis. Funding for this research came in part from USDA HATCH project 863H.。
乙酰丙酸还原胺化制备5-甲基-2-吡咯烷酮
第51卷第2期2017年3月生物质化学工程Biomass Chemical EngineeringV〇1.51 N〇.2Mar. 2017floi:10.3969/j.issn.1673-5854.2017.02.004•研究板告----生物质化学品•乙酰丙酸还原胺化制备5-甲基-2-吡咯烷酮王彦钧，李铮，蒋叶涛，陈伟，曾宪海，孙勇*，林鹿(厦门大学能源学院；厦门市现代农业生物质高值化技术重点实验室，福建厦门361005)摘要：以曱酸铵为氮源和氮源，N，N-二曱基曱酰胺为溶剂，探讨了曱酸铵直接还原胺化乙酰丙酸制备5-曱基-2-吡咯烷酮的反应途径及机理。
通过实验分别考察了反应温度、反应时间、乙酰丙酸与曱酸铵的总质量分数和物质的量比、体系 p H值等反应条件对5-曱基-2-吡咯烷酮得率的影响趋势。
结果表明，适当提高反应温度、延长反应时间、提高乙酰丙酸与曱酸铵的物质的量比和总质量分数、增加体系p H值均有利于提高5-曱基-2-吡咯烷酮的得率。
同时，考察了不同溶剂和乙酰丙酸衍生物在该反应体系中的应用，结果表明极性非质子溶剂曱酰胺、N，N-二曱基乙酰胺、二曱亚砜亦可作为该中体系反应的反应溶剂，乙酰丙酸曱酯、a -当归内酯可作为反应底物在该体系下制备5-曱基-2-吡咯烷酮。
关键词：吡咯烷酮；还原胺化；乙酰丙酸；生物质中图分类号:TQ31;TQ35 文献标识码:A 文章编号：1673-5854(2017)02-0019-07 l i e l u c l m.〇丨’l e\u l M i i c\c i(l l o 5-\|r||n|-2-|n i.i.〇|i(|〇iieWANG Yanjun,LI Zheng,JIANG Yetao,CHEN Wei,ZENG Xianhai,SUN Yong,LIN Lu (College of Energy;Key Laboratory of High-valued Conversion Technology of Agricultural Biomass inXiamen,Xiamen University, Xiamen 361005, China )Abstract ：The reductive amination of levulinic acid with ammonium formate as hydrogen and nitrogen donor to synthesize 5- methyl-2-pyrrolidone(5-MeP) in DMF solvent was developed and the mechanism of this process was proposed. The effects of various reaction conditions including temperature, reaction time, mass fraction and molar ratio of levulinic acid with ammonium for^nate and pH value on 5-methyl-2-pyrrolidone yield were investigated. Meanwhile, different solvents and levulinate derivatives were investigated in this system. The results showed that the properly increasing temperature, reaction time, the molar ratio and total mass fraction of levulinic acid and ammonium formate,and the pH value of system could improve the yield of 5-methyl-2- pyn’olidone. The polar aprotic solvents including formamide，DMA，DMSO and levulinate derivatives,such as methyl levulinate and a-angelica lactone,could also be respectively used as solvents and substrates in this system,too.Key words ： pyrrolidone ； reductive amination ； levulinic acid ； biomass随着全球变暖、能源危机等问题不断加剧，由可再生能源替代传统的化石能源作原料生产大宗化 学品和材料成为了研究热点[|_4]。
食品科学导论课后题
Chapter 1Overview of Food ScienceReview Questions (P18)1.Away-from-home meals captures 45 percent of the U.S. food dollar. (P10)2.Why have the international activities of food industries increased? (P16)Aside from the worldwide demand for food and food products, the recent trends to decrease trade tariffs has stimulated the international activities in the food industry.Improvements in transportation and communication have also increased the international activities of food industries. all seven product lines along which the food industry is divided. (P4)Cereal and bakery productsMeat, fish, and poultryDairy productsFruits and vegetablesSugars and other sweetsFats and oilsNonalcoholic beverages/alcoholic beverages4.List the four artificial divisions of the food industry. (P4)ProductionManufacturing/processingDistributionMarketing5.Consumption of cheese has increased, whereas consumption of red meat has declined overthe last 27 years. (P17)6.List four reasons that influence people and the kind of food they eat. (P17)The kinds of foods people eat change in response to many influences, such as demographic shifts; supply of ingredients; availability and costs of energy; politics; scientific advances in nutrition, health, and food safety; and changes in lifestyle.7.About 10000 new food products are introduced each year. (P17)8.Explain how the consumer votes in the marketplace. (P3)Consumers vote every day in the marketplace with their dollars.9.Define an allied industry. (P11)An allied industry produces nonfood items that are necessary for marketing food.pare the spending on food in the United States to that of Spain and Greece. (P6-7) Americans spent only about 8 percent of their personal consumption expenditures for food to be eaten at home. This compares with 18 percent for Spain and 32 percent for Greece. Chapter 2Review of Chemistry (P31)1.The atom is the smallest unit of an element that still exhibits the properties of that element.(P21)2.Define a molecule. (P26)A molecule is the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance. and describe the two divisions of metabolism. (P28)Anabolism, reactions involving the synthesis of compounds.Catabolism, reactions involving the breakdown of compounds.4.List the elements most important to life. (P22)The elements important to life include carbon, hydrogen, nitrogen, and oxygen.5.How are covalent bonds formed? (P22)Covalent bonds are formed by the sharing of a pair of electrons.6.The atomic number of an atom is the total number of protons. The atomic weight of an atomis the total number of protons plus neutrons. (P21)7.Salt is an example of a/an ionic bond. (P25)8.Explain the oxidation-reduction reaction. (P26)The rusting of metals, the process involved in photography, the way living systems produce and use energy, and the operation of a car battery are but a few examples of oxidation-reduction reactions.9.Chemical properties of an element are determined by the number of electrons in theoutermost energy level of an atom. (P22)10.All carbon atoms have four bonds to account for. What are the names of the bonds? (P29) Each carbon can connect to another carbon, a hydroxyl, a hydrogen, an amino group, an oxygen.Carbon-carbon bonds; carbon-hydroxyl bonds, carbon-hydrogen bonds, carbon-amino bonds; carbon-oxygen bonds.Chapter 3 Chemistry of Foods (P62)1.What is the chemical composition of a carbohydrate? (P34)A carbohydrate is composed of carbon and water and have a composition of C n(H2O)n.2.List the three functions of proteins in food. (P48)Proteins contribute to the color, texture, and flavor of foods.3.What is the difference between a monosaccharide and a disaccharide? (P35)A monosaccharide may have 5 or 6 carbons. A disaccharide is made of two monosaccharides. five functions carbohydrates play in foods. (P34-35)Carbohydrates enhance flavor, contribute to texture, prevent spoilage, influence color, and give structure.Flavor enhancing and sweetening due to caramelization Water binding Contributing to texture Hygroscopic nature/water absorption Providing source of yeast food Regulating gelation of pectin dispersing molecules of protein or starch Acting to subdivide shortening for creaming control crystallization Preventing spoilage Delaying coagulation protein Giving structure due to crystals Affecting osmosis Affecting color of fruits Affecting texture (viscosity, structure) Contributing flavor other than sweetness5.Explain two functions of water in the body. (P58)Carries nutrients and wastesn Maintains structure of molecules Participates in chemical reactions Acts as a solvent for nutrients Lubricates and cushions joints, spinal cord, and fetus (during pregnancy) Helps regulate body temperature Maintains blood volume6.Triglycerides, fatty acids, phospholipids, some pigments, some vitamins, and cholesterol areclassed as lipids. (P48)7.Fatty acid molecules that are unsaturated contain what are known as double bonds. A fattyacid that contains one double bond is called mono- unsaturated. Fatty acids that contain two or more double bonds are called polyunsaturated. (P50)8.List the fat- and water-soluble vitamins. (P53)Fat soluble vitamins include vitamins A, D, E, and K.The water-soluble vitamins include the B vitamins and vitamin C.9.Choline is part of several major phospholipids critical for normal membrane structure andfunction, is used by the kidney to maintain water balance, and is used to produce the important neurotransmitter acetylcholine. (P59) ten minerals important in nutrition. (P55)Microminerals important in nutrition include:Chromium Cobalt Copper Fluorine Iodine Iron Manganese Molybdenum Nickel Selenium Silicon Tin Vanadium ZincChapter 4 Nutrition and digestion (P79-80) six minerals required by the body. (P73)Calcium; Phosphorus; Iron; Copper; Magnesium; Sodium; Potassium; Chloride; Zinc; Iodine; Manganese; Selenium.2.Identify the protein requirement for a 19-year-old male and female. (P68)Protein needs is about 61 grams per day for a 19-year-old male and is 44 grams per day for a female at the same age.3.Describe the function of protein in diet. (P69)Protein provides essential amino acids, and nitrogen for the synthesis of other nitrogen-containing compounds.Enough protein in the diet can prevent the dietary diseases kwashiorkor or marasmus. Protein provides essential amino acids.Protein also provides nitrogen for the synthesis of purines, pyrimidines, porphyrin in nucleic acids, ATP, hemoglobin, and cytochromes.Enough protein in the diet of people can prevent the dietary diseases kwashiorkor or marasmus.4.How many calories are in 1 gram of protein, carbohydrate, fat, and alcohol? (P65)Proteins and carbohydrates provide about 4 calories per gram. Fat contributes about 9 calories per gram. Alcohol supplies about 7 calories per gram.5.Linoleic acid is an essential fatty acid. (P71)6.Identify the organ of digestion that receives enzymes from the pancreas. (P76)The small intestine receives enzymes from the pancreas.7.During digestion, enzyme such as aminopeptidase, carboxypeptidases, and dipeptidaseconvert polypeptides into amino acids. (P77)8.What nutritional deficiency causes kwashiorkor and marasmus? (P69)Protein deficiencies can lead to kwashiorkor or marasmus.9.List five essential amino acids. (P69)Phenylalanine; Tryptophan; Histidine; Valine; Leucine; Isoleucine; Lysine; Methionine; Threonine; Arginine10.What factor determines protein quality? (P69)Ratios of essential amino acid.Chapter 5Food composition (P87)1.How many Calories and grams of protein are in 3 oz. of Froot Loops ®cereal? (P578)330 kilocalories (Calories) and 6 grams of protein are in 3 oz. of Froot Loops ®cereal.2.How many grams of fat are in one slice of cheese pizza? (P588)9 grams of fat are in one slice of cheese pizza.3.Describe item #4270. (P580)3 grams of water, 185 kilocalories, 2 grams of protein, 11 grams of fat, 18 milligrams of cholesterol, 26 grams of carbohydrate, 13 milligrams of calcium, 34 milligrams of phosphorous, 1 milligram of iron, 82 milligrams of potassium, 82 milligram of Sodium, 20 IU of V A, 0.06 milligrams of thiamin, 0.06 milligrams of riboflavin, and 0.6 milligrams of niacin are in 4 chocolate chip cookies.3g water, 185 Cal, 2g protein, 11g fat, 18mg cholesterol, 26g carbohydrate, 13mg Ca, 34 mg P, 1mg Fe, 82mg K, 82mg Na, 20 IU V A, 0.06mg thiamin, 0.06mg riboflavin, and 0.6mg niacin are in 4 chocolate chip cookies.4.List three methods for determining the composition of food. (P83)The methods for determining the composition of food are spectrophotometry, liquid chromatography, and gas chromatography.5. A small calorie is defined as the amount of heat required to raise the temperature of one gramof water one ℃. (P84)6.Describe two uses of a food composition table. (P86)Food composition tables are used to evaluate the nutritional value of food supplies, to develop food distribution programs, to plan and evaluate food consumption surveys, to provide nutritional counseling, and to estimate the nutritional content of individual diets.Food composition tables are used to evaluate diets and food supplies. four factors that affect the nutrient content of foods. (P83)Nutrient content of foods is influenced by variety, season, geographical differences, stage of harvesting, handling, commercial processing, packaging, storage, display, home preparation, cooking, and serving.8.Explain the relationship between Calorie, Kcal, calorie, and cal. (P84)A Calorie is a metric unit of heat measurement. The small calories (cal) is the amount of heat required to raise the temperature of 1 gram of water from 14.5° to 15.5 ℃.A large calorie, or kilocalorie (Cal), usually referred to as a calorie and sometimes as a kilogram calorie, equals 1000 cal.9.Identify the following abbreviations: oz, mg, IU, RE, mono, sat, poly, carb, chols. (P86)Oz=ounce, mg=miligram, IU=International Unit, RE=Retinol Equivalent, mono=monounsaturated, sat=saturated, poly=polyunsaturated, carb=carbohydrate, chols=cholesterol.10.In terms of energy and protein, what is the difference between a slice of white bread and aslice of whole wheat bread?(P576)A slice of white bread provides less energy and protein than a slice of whole wheat bread does.Chapter 6 Quality factors in foods (P107)1.List three components of reflected light used to define colors. (P91)Value, hue, and chroma. one instrument used to measure texture. (P93-94)Compressimeter—determine the compressibility of cakes and other “spongelike ” products; Penetrometer—measure gel strength;Warner-Bratzler shear apparatus—evaluating meat tenderness;Brookfield viscometer—measure the viscosity;Succulometer;Tenderometer.3.Discuss what humans can taste and what they smell and how this forms food flavor. (P95) Humans can taste sweet, salty, sour, and bitter and smell fruity, astringency, sulfur, hot. Food flavor is a combination of taste and smell.4.Identify the following acronyms: AMS, HACCP, TQM, GMP, CID. (P99, 104-106) AMS—the Agricultural Marketing ServiceHACCP—Hazard Analysis and Critical Control PointTQM—Total Quality ManagementGMP—Good Manufacturing PracticesCID—Commercial Item Descriptions5.Industry and AMS develop and maintain CIDs. (P99)6.List six factors that can influence the flavor of food. (P96)Depending on the food, flavor can be influenced by bacteria, yeasts, molds, enzymes, heat/cold, moisture/dryness, light, time, additives.7.Changes in the texture of food are often due to water status. (P94)8.What qualities do consumers expect of their food? (P106)Consumers expect certain qualities from their food. These include color, flavor, texture, and even size.9.The study of the science of the deformation of matter is called rheology. (P93)10.How do fats or lipids affect the texture of food? (P97)Lipids (fats) are softeners and lubricants used in cakes.Chapter 7 Unit operations in food processing (P122-123)1.The manufacture of ice cream is an example of a/an swept surface heat exchanger. (P117)2.Why are foods packaged? (P120)Packaging is used for a variety of purpose including shipping, dispensing, improving the usefulness of the product, and protection from microbial contamination, dirt, insects, light, moisture, drying, flavor changes, and physical alterations.Attractive packaging also helps with marketing of the food product.3.Specific heat is the amount of heat required to change the temperature of a unit mass ofproduct a specific temperature without changing the material. (P115) the three methods for separating foods. (P111-113)Three methods for separating foods are cream separator, clarification, and membrane processes.5.What are the two types of fluid flow pumps? (P114)Centrifugal pump and positive pump are two types of fluid flow pumps.6.Plate heat exchanges pass fluid over a plate where a heating or cooling medium is beingpassed up or down on the other side of the plate. (P116)7.List the four factors affecting the mixing of food products. (P114)Factors affecting the mixing of food are design of impeller, diameter of impeller, speed, and baffles.8.Why is it important to handle food materials carefully? (P110)To maintain sanitary conditions, minimize losses, maintain quality, and minimize bacterial growth.9.Explain the three common methods of drying foods. (P119)Three common methods of drying are sun or tray drying, spray drying, and freeze drying. 10.List three membrane processes for separating food products. (P112)Reverse osmosis, ultrafiltration, and microfiltration.Chapter 8 Food deterioration (P136) the two environmental conditions that affect microbial growth on food. (P127) Environmental conditions that affect microbial growth include temperature and oxygen. the three general categories of food deterioration. (P125)The three general categories of food deterioration are: physical, chemical, and biological.3.Some of the post harvest enzymes are desirable in food preservation. (P136)4.Why do foods have a shelf life? (P136/125)All foods undergo deterioration. All foods have a time limit of their usefulness—shelf life. 5.The growth of aerobes is slowed by removing the oxygen; while providing oxygen limits thegrowth of anaerobes. (P135)6.List four factors that cause food deterioration. (P125)Factors that cause food deterioration are many, including light, cold heat, oxygen, moisture, dryness, othertypes of radiation, enzymes, microorganisms, time, industrial contaminants, and macroorganisms (insects, mice, and so on).7.What is a food-borne disease? (P127)Food-borne disease is any disease resulting from the consumption of food.8.Give four preservation techniques to prevent food deterioration. (P132-135)Food preservation involves the use of heat, cold, drying, acid, sugar and salt, smoke, atmosphere, chemicals, radiation, and mechanical methods.9.Why are some fruits and vegetables washed immediately after being picked? (P128)Some fruits and vegetables are washed to remove internal heat and cool immediately after being picked in order to minimize post-harvest biochemical changes. four food enzymes and describe their function. (P129-131)Ascorbic acid oxidase, oxidize ascorbic acid to dehydro form destroying the browning prevention ability.Beta-amylase, with fungal glucoamylase produces mixtures of fermentable sugars: glucose, maltose.Bromelain, acts on collagen to hydrolyze peptides, amides, and esters from the non-reducing end.Catalase, removes residual H2O2 treated foods, converts H2O2 to H2O and oxygen.Chapter 9 Heat (P154)1.The most heat resistant microbe in canned foods is Clostridium botulinum. (P144)2.What are the two main objectives of pasteurization? (P143)Destroy all pathogenic microorganisms that might grow in a specific product;Extension of shelf life by decreasing number of spoilage organisms present. four types of preservatives achieved by heating. (P142)Sterilization, commercial sterility, pasteurization, and blanching.4.In the thermal death curve, the D value relates to the time to reduce the number ofmicroorganisms, and the Z value relates to the temperature required to decrease the microorganisms. (P148)5.Heating before packaging requires what type of packaging? (P148)Heating after packaging requires aseptic (germ-free) packaging.6.Conduction heating is thermal transfer due to collisions of hot food particles with cooler ones.(P145)7.What is the difference between a still retort and an agitating retort? (P149)In the still retort process, the product is placed in a container and then heated in steam atmosphere without agitation.In the agitating retorts the product is agitated during cooking.8.Identify the two factors to pick the right heat treatment severity for a specific food. (P143)To pick the right heat treatment severity for a specific food, two factors must first be determined:Time-temperature combination required to inactivate the most resistant microbe;Heat penetration characteristics of the food and the container.9.Define conduction heating. (P145)Conduction heating is thermal transfer due to collisions of hot food particles with coolerones.10.Radiation is the transfer of energy in the form of electromagnetic waves. (P145)Chapter 10 Cold (P169-170) the three methods of freezing. (P164)Freeze the product in air;Freeze the product with directly contact;Immersion freezing.2.List the four requirements of refrigerated storage. (P159)Refrigerated storage requires low temperatures, air circulation, humidity control, and modified gas atmosphere.3.Identify four changes in food during refrigeration. (P159)During refrigerated storage, foods can experience chill injury, flavor absorption, and loss of firmness, color, flavor, and sugar.4. A key factor in food freezing is how quickly the food is frozen. (P163)5.Describe the temperature difference between cooling, refrigeration, and freezing. (P157) Cooling: temperature from 68˚ to 28˚F (16˚ to -2 ˚C);Refrigeration: temperature from 40˚ to 45˚F (4.5˚ to 7 ˚C);Freezing: temperature from 32˚ to 0˚F (0˚ to -18˚C).6.Why do food processors blanch vegetables prior to freezing them? (P160)Enzymes will maintain a certain level of activity during freezing. the two types of containers for home freezing use. (P165)Rigid containers and flexible bags or wrappings.8.Freezing cannot improve the flavor or texture of any food. (P167)9.Explain why a freezer should not be overloaded with unfrozen food. (P167)Overloading slows down the freezing rate, and foods that freeze too slowly may lose quality.10.List the three things packaging for frozen foods protects against. (P165)Packaging for frozen foods protects against dehydration, light, and air.Chapter 11 Drying and dehydration (P187)1.List the three drying methods. (P177)Common drying methods are: air convection, drum, vacuum, freeze.2.Dehydration results in decreased weight and volume of a product a nd shipping costs. (P186)3.Vacuum drying produces the highest quality of product by is also very costly. (P178)4.What is ultrafiltration? (P182)Ultrafiltration is a membrane filtration process operating at 2 to 10 bars pressure and allowing molecules the size of salts and sugars to pass through the membrane pores, while molecules the size of proteins are rejected.5.The principle of freeze-drying is that under conditions of low vapor pressure (vacuum), waterevaporates from ice without the ice melting. (P178)6.The purpose of drying is to remove enough moisture to prevent microbial growth. (P173)7.Define sublimation. (P178)Water goes from a solid to a gas without passing through the liquid phase. This is called sublimation.8.What types of foods are dried using a drum or roller driers? (P177)Drum or roller driers are used for drying liquid foods, purees, pastes, and mashes.9.Discuss the two problems with drying of a food product. (P173)Dried foods are not sterile. Many spores survive in dry areas of food.Drying never completely removes all water.10.List three chemical changes that occur during drying. (P175-176)Several chemical changes can occur during drying, including: caramelization, enzymatic browning, nonenzymatic browning, loss of ease of rehydration, loss of flavor.Chapter 12 Radiant and electrical energy (P197)1.Describe ohmic heating. (P196)Ohmic heating is the heating of a food product by using an alternating current flowing between two electrodes. the two requirements for irradiation. (P190)Two requirements for the irradiation process include:A source of radiant energy;A way to confine that energy.3.Radiation is broadly defined as energy moving through space in invisible waves. (P190)4.Explain ionizing radiation. (P190)Ionizing radiation, also known as irradiation, is a method of food preservation. These shorter wavelengths are capable of damaging microorganisms.5.List the four ways in which irradiation is most useful. (P192)Irradiation is most useful in four areas: preservation; sterilization; control of sprouting, ripening, and insect damage, and control of food borne illness.6.Describe how microwaves heat food. (P197)Microwaves heat foods by generating heat inside the food due to water friction.7.When salt is added to water, it changes the microwave heating characteristics in two differentdirections. (P195)8.List three specific ways irradiation has been approved for use by the FDA. (P191-192)For eliminating insects from wheat, potatoes, flour, spices, tea, fruits, and vegetables.To control sprouting and ripening.Use irradiation on pork to control trichinosis.To control Salmonella and other harmful bacteria in chicken, turkey, and other fresh and frozen uncooked poultry.To control pathogens in fresh and frozen red meats such as beef, lamb, and pork.9.Food composition influences microwave heating of food in what two ways? (P195)Food composition does not only influence the loss factor, but also penetration depth.10.Irradiation cannot be used on what two specific products? (P192)Irradiation cannot be used with dairy products and some fruits, such as peaches and nectarines.Chapter 24 Environmental Concerns and ProcessingReview Questions (P448-449)1.Water serves as a universal solvent. (P440)2.List five methods of conserving water during food processing. (P447)Always treat water as a raw material with a real cost; Set water conservation goals for the plant; Make water conservation a management priority; Install water meters and monitor water use; Train employees how to use water efficiently; Use automatic shut-off nozzles onall water hoses; Use high-pressure, low volume cleaning systems; Do not let people use water hoses as brooms; Reuse water where possible; Minimize spills of ingredients and of raw and finished product on the floor; Always clean up the spills before washing.总是把水看成是有成本的原料，制定工厂的节水目标，使节水成为管理首要考虑的内容，安装水表管理水的使用，培训员工怎样有效用水，在所有水管上安装自动关水喷嘴，使用高压低量的清洁系统，不允许用水管冲洗，尽可能重复利用水，尽量减少配料、原料和产品的溢、撒，清洗前总是先擦干净。
食品营养学(双语)
翻译：①All you have to do is choose a selection of foods that supplies appropriate amounts of the essential nutrients, fiber ,and energy without excess intakes of fat ,sugar ,and salt and be sure to get enough exercise to balance the foods you get.所有你必须做的就是挑选食物，这些食物能够提供质量的必需营养物质，纤维素和能量，不过多摄入脂肪，糖和盐并确保能得到足够的锻炼平衡你所吃的食物。
②They also make some general statements about energy intakes ,but they do little to protect people from excess intakes of fats ,sugar ,salt ,and other food constituents believed to be related to chronic disease.他们也做些一些关于能量摄入的一般性说明，但是他们几乎没做多少来保护人们以免过多摄入脂肪、糖、盐和其他与慢性疾病有关的食物成分。
他们也制定了一些关于能量摄入的规定，但是这些措施在防止人们摄入过量的与慢性疾病有关的脂肪，糖盐以及一些其他的食物成分方面效果甚微。
③In practice ,however ,diet planners must be sure to choose mostly nutrient-dense foods in each group because some processes strip foods of some nutrients and add calories from fats. With this caution ,the daily food guide can provide a reasonable road map for diet planning.然而，实际上，膳食计划者必须确保每类食品中选择通常高营养密度的食物，因为在一些加工过程中除去食品中一些营养素并添加一些脂肪而增加能量。
纳米技术用作煤炭助燃催化剂的小作文
纳米技术用作煤炭助燃催化剂的小作文-概述说明以及解释English Answer:Nanotechnology has shown great potential in various fields, and one promising application is its use as a catalyst for coal combustion. Coal is a widely used energy source, but its combustion process releases harmful pollutants into the atmosphere. By utilizing nanomaterials as catalysts, we can enhance the efficiency of coal combustion and reduce emissions.Nanocatalysts have a high surface area to volume ratio, which allows for better interaction between the catalyst and coal particles. This increased interaction leads to a more efficient combustion process, resulting in higher energy output and lower pollutant emissions. Additionally, nanocatalysts can selectively target specific pollutants, such as nitrogen oxides and sulfur oxides, further reducing their release into the environment.One example of a nanocatalyst used in coal combustion is metal nanoparticles supported on a mesoporous material. These nanoparticles act as active sites for the oxidation of coal,promoting its combustion at lower temperatures. The mesoporous material provides a large surface area for coal adsorption and enhances the dispersion of the nanoparticles, improving their catalytic performance.Furthermore, nanocatalysts can be engineered to have specific properties tailored for coal combustion. For example, the size, shape, and composition of nanoparticles can be optimized to maximize their catalytic activity. Surface modifications can also be applied to enhance the stability and durability of the catalysts under high-temperature conditions.In conclusion, nanotechnology offers exciting opportunities for the development of coal combustion catalysts. By harnessing the unique properties of nanomaterials, we can improve the efficiency of coal combustion and minimize its environmental impact.中文回答：纳米技术在各个领域展现出巨大的潜力，其中一个有前景的应用是将其用作煤炭燃烧的催化剂。
一氧化氮抗癌的英语
一氧化氮抗癌的英语The Potential of Nitric Oxide in Cancer Therapy.Cancer, a complex and deadly disease, has been a significant challenge in medical research for decades. With the constant evolution of scientific understanding and technological advancements, researchers are exploring various avenues to combat this debilitating condition. One such avenue is the study of nitric oxide (NO) and its potential anticancer properties.Nitric oxide is a small, gaseous molecule with a wide range of biological functions. It is naturally produced in the body by various cells, including endothelial cells, macrophages, and neurons. NO plays a crucial role in regulating vascular tone, immune response, and neurotransmission. However, its role in cancer biology is much more complex and multifaceted.Mechanism of Nitric Oxide in Cancer Therapy.The exact mechanism of how nitric oxide exerts its anticancer effects is not fully understood. However, several studies have identified several potential mechanisms.1. Induction of Apoptosis: Nitric oxide has been shown to induce apoptosis, or programmed cell death, in cancer cells. This process involves the activation of specific enzymes that lead to the death of the cancer cell.2. Inhibition of Angiogenesis: Cancer cells require a network of blood vessels to supply them with oxygen and nutrients. Nitric oxide can inhibit the formation of these blood vessels, thereby starving the cancer cells of their essential resources.3. Enhancement of Immune Response: NO can also stimulate the immune system, making it more effective at attacking cancer cells. This is achieved by activating immune cells and enhancing their ability to recognize and destroy cancer cells.4. Direct Cytotoxicity: Nitric oxide can directly damage cancer cells by reacting with cellular components, leading to their destruction.Applications of Nitric Oxide in Cancer Therapy.The potential applications of nitric oxide in cancer therapy are diverse and range from direct use as a therapeutic agent to its use as a radiosensitizer or chemosensitizer.1. Direct Therapeutic Agent: NO-releasing agents, such as nitrosoureas and nitric oxide donors, have been studied for their direct anticancer effects. These agents can be administered systemically or locally to target specific cancers.2. Radiosensitizer: Radiation therapy is a common treatment for cancer, but its effectiveness can be limited by tumor hypoxia (low oxygen levels). Nitric oxide has been shown to improve tumor oxygenation, thereby increasing thesensitivity of cancer cells to radiation therapy.3. Chemosensitizer: Similar to radiation therapy, chemotherapy can also be limited by tumor hypoxia. Nitric oxide has been found to enhance the cytotoxicity of some chemotherapy drugs, making them more effective against hypoxic tumor cells.4. Immunotherapy: By stimulating the immune system,nitric oxide can enhance the effectiveness of immunotherapy, a treatment that uses the patient's immune system to attack cancer cells.Challenges and Future Directions.Despite the promising preclinical data, the clinical translation of nitric oxide-based cancer therapies has been challenging. One of the main hurdles is the difficulty in delivering nitric oxide selectively to tumor cells while minimizing potential side effects. Additionally, the exact dosing and scheduling of nitric oxide therapy need to be carefully optimized for each cancer type and patient.Future research in this area will focus on developing more selective and potent nitric oxide donors, as well as combining them with other therapies to enhance their efficacy. Additionally, understanding the precise mechanism of how nitric oxide exerts its anticancer effects will be crucial for developing more targeted and effective therapies.In conclusion, nitric oxide offers a unique and promising approach to cancer therapy. Its ability to target cancer cells while sparing normal tissue holds great potential for improving patient outcomes. As research in this area continues to progress, we may soon see nitric oxide-based therapies become a reality in the fight against cancer.。
Nitrogen poisoning effect on the catalytic cracking of gasoil
Nitrogen poisoning effect on the catalytic cracking of gasoilG.Caeiro a ,b ,A.F.Costa c ,H.S.Cerqueira c ,P.Magnoux b ,J.M.Lopes a ,P.Matias a ,b ,F.Ramoˆa Ribeiro a ,*aCentro de Engenharia Biolo´gica e Quı´mica,Instituto Superior Te ´cnico,Av.Rovisco Pais,1049-001Lisboa,Portugal bLaboratoire de Catalyse en Chimie Organique,Chimie 7A-3,40Avenue du Recteur Pineau,86022Poitiers Cedex,FrancecPetrobras,Centro de Pesquisas e Desenvolvimento Leopoldo A.Miguez de Mello (CENPES),Av.Jequitiba´950,Ilha do Funda˜o,21941-598Rio de Janeiro,RJ,Brazil Received 19October 2006;received in revised form 29November 2006;accepted 30November 2006Available online 21December 2006AbstractThis research work consisted in the assessment of the damaging effect of basic nitrogen in the performance of industrial catalytic cracking boratory evaluation of an industrial equilibrium catalyst was done with four feedstocks with very distinct nitrogen contents:a gasoil with 1307ppm of basic N (feedstock A);feedstock A after an acid treatment with the objective of partially removing the basic nitrogen (feedstock B:135ppm of basic N);feedstock B after adding 1172ppm of quinoline (feedstock C:1307ppm of basic N);and feedstock A after adding 1172ppm of quinoline (feedstock D:2479ppm of basic N).Characterization of the gasoils showed that only the basic nitrogen content was affected by the acid treatment.The evaluation results showed that basic nitrogen reduces the gasoil cracking conversion in 5–10wt%points,depending on the catalyst to oil ratio.In addition,at constant conversion,the increase in basic nitrogen content also resulted both in a decrease in gasoline yield and an increase in coke and hydrogen yields.Nitrogen contained in the quinoline molecule had similar effects to that present in the original gasoil.#2007Elsevier B.V .All rights reserved.Keywords:Catalytic cracking;Vacuum gasoil;Nitrogen poisoning;Acid treatment;Equilibrium catalyst1.IntroductionThe simple distillation of crude oil does not produce the necessary amounts of LPG (liquefied petroleum gas),gasoline and diesel.Nowadays,fluid catalytic cracking (FCC)is the most used process in the production of LPG and gasoline from either vacuum distillation gasoil (VGO)or atmospheric distillation residue (ATR).FCC is still one of the most important industrial processes worldwide [1,2].The unique ability of FCC units to adjust their operating conditions allows them to process many feedstock types.Currently FCC feedstocks are constituted mainly by virgin gasoils,mainly VGO (vacuum gasoil).This crude oil cut is constituted essentially by naphtenes,aromatics and alkanes.Apart from hydrocarbons,FCC feeds also contain non-negligible amounts of metals:Ni,V ,Cu,Fe,Na,K,Ca,Mg (0–200ppm),oxygen (0–2%),sulfur (0–7.5%)and nitrogen (0–2000ppm).A typical VGO cut contains approximately 25–30%of the nitrogen existent in the corresponding crude oil.The poisoning effect of (basic)nitrogen compounds has been known for several decades [3–20].Recently however,due to increasing level of impurities in the FCC feedstock,it constitutes an increasingly significant problem.In addition,in the last few years,increasing amounts of vacuum distillation residue have been added to FCC charges causing a sharp increase on the nitrogen content.Vacuum residue contains about 70–75%of the nitrogen present in the corresponding crude oil.For the lighter fractions of crude oil,nitrogen is mainly in the form of basic compounds while in heavier fractions of crude oil non-basic nitrogen compounds are predominant [21].Normally,the nitrogen present in crude oil occurs in high molecular weight molecules containing other heteroatoms (S,O).Despite this fact,compounds of small and medium molecular weight with well defined structures were also/locate/apcataApplied Catalysis A:General 320(2007)8–15*Corresponding author.Tel.:+351218419073;fax:+351218419062.E-mail addresses:ramoa.ribeiro@ist.utl.pt ,qramoa@ist.utl.pt (F.R.Ribeiro).0926-860X/$–see front matter #2007Elsevier B.V .All rights reserved.doi:10.1016/j.apcata.2006.11.031isolated from crude oil cuts:alkyl derivatives of pyridine, quinoline,isoquinoline,acridine and phenanthridine.The others are not basic and usually include a pyrrol nucleus: derivatives of pyrrole,indole and carbazole[21].Several approaches can be used to minimize the harmful effects of nitrogen compounds before the catalytic cracking process: 1.Hydrotreating:well known technique used to decrease the nitrogen content in feedstocks.This process requires high pressures and temperatures and is therefore expensive. 2.Adsorption:use of an acidic solid adsorbent which captures the basic nitrogen compounds.This method has been used to separate basic asphaltenes from feedstocks[22]and for syncrude denitrogenation[23].3.Liquid/liquid extraction:use of an immiscible solvent to extract nitrogen compounds[24–26].The method has been recommended to separate nitrogen compounds from shale oil.4.Neutralization:using acid additives to neutralize basic nitrogen compounds.The products resulting from neutra-lization are subsequently separated[26–28].5.Another possibility is to use a nitrogen-resistant FCC catalyst,instead of pre-treating the FCC feedstock.The major advantage of this method is a considerable decrease in the pretreatment process cost.In the present work,the deactivating effect of nitrogen was assessed for the catalytic cracking reaction of an industrial FCC feedstock over an industrial equilibrium catalyst.Several feedstocks were used with different properties in order to isolate the effect of basic nitrogen.The comparison between the cracking behavior of different charges was done at different levels:conversion,product distribution and coke nature.2.ExperimentalThe used catalyst is an industrial FCC equilibrium catalyst supplied by Petrobras with no H-MFI additives content.Its physicochemical properties are listed in Table1.The elemental analysis of the equilibrium catalyst was done by RX fluorescence in a Phillips PW1710spectrometer.The used equipment presented a Cu anode and graphite monochromator. The samples initially in the powder form were transformed into vitreous and homogeneous wafers after fusion with Li2B4O7.The nitrogen adsorption measurements were carried out in a Micromeritics Gemini2375equipment.The surface area was calculated by BET method and the microporous volume was determined by the t-plot method using the Harkins and Jura standard isotherm;the selected thickness values varied between 3.2and5.5A˚.The FCC industrial gasoil(feedsock A)was submitted to a three step treatment[27,28]as follows:(i)addition of a stoichiometric amount of H2SO4(95%),(ii)vigorous agitation for1h and,(iii)decantation at1308C for12h.After the treatment,approximately75%of the charge(less dense phase) was reclaimed and used as a feedstock to the catalytic tests (feedstock B),the high nitrogen content residue was rejected. Other charge was prepared by addition of quinoline(1172ppm) to the treated gasoil in order to get1307ppm(feedstock C),the exact amount of basic nitrogen of the original feedstock.Finally a fourth feedstock was prepared by addition of1172ppm of quinoline(the same quantity added to charge C)to the original feed(feedstock D).Basic nitrogen contents were measured according to UOP269method.For the catalytic tests afixed bed ACE1unit was used.The tests were performed in a steel reactor at5358C and atmospheric pressure.The reactor feed was constituted by constantflows of40ml minÀ1of nitrogen and1.25g minÀ1of feedstock.The tests were carried out with9g of catalyst in order to obtain a contact time similar to the obtained in the FCC riser.The injection times were changed in order to achieve CTO (catalyst to oil ratio)values of5,6,7and8.After the catalytic experiments,liquid and gaseous effluents were collected in a receiver and a gas collection bottle,respectively.The gaseous effluent consists of a mixture of dry gas(H2,methane,ethane and ethene),LPG(C3s and C4s)and gasoline(C5plus)and was analyzed in a Agilent6890N gas chromatograph,equipped with two thermal conductivity detectors and two columns:a Porapak (20%sebaconitrile/80%chromosorb PAW Q)and a molecular sieve,both maintained at508C.The liquid effluent was analyzed by simulated distillation in a Agilent6890gas chromatograph,equipped with aflame ionization detector and HP-1methyl silicon columns.The amounts of gasoline,light cycle oil(LCO)and decanted oil(DO)were quantified considering the temperature ranges of35–216,216–344,and 344+8C,respectively.The liquid products were condensed atÀ108C and analyzed by another GC.For the analysis the liquid is divided into three lumps:gasoline,LCO and DO.The cracking conversion was defined as:X=100À(LCO+DO).Conversion and yields were determined with weight percent.After reaction the catalyst was stripped with40ml minÀ1nitrogen for350s. Coke contents were determined in a LECO CS244apparatus by total combustion at10508C.Nitrogen and hydrogen contents were also determined by total combustion followed by GC.A three steps procedure[29]was used in order to extract the soluble coke from the catalyst.First of all,the catalyst matrix was dissolved in a HF solution(40%)at room temperature; second,the solution containing the coke molecules was neutralized with NaHCO3;the third step consisted in a two-step extraction with CH2Cl2.Coke is divided in two categories according to its solubility in dichloromethane:(i)soluble cokeTable1Physicochemical properties of the tested equilibrium catalystElemental composition(wt%)SiO255.3Al2O340.1Na2O0.53Re2O3 2.48V micro(cm3/g)0.052Area(m2/g)142V(ppm)3074Ni(ppm)3579G.Caeiro et al./Applied Catalysis A:General320(2007)8–159and(ii)insoluble coke.The soluble coke is analyzed according to Ref.[29],and the insoluble coke is recovered byfiltration.3.Results and discussion3.1.Characterization of the tested chargesAs described earlier four distinct charges were tested during this work,only one of them is a real industrial charge(feedstock A).As it will be seen,the fact that all the other charges derive from the same sample is rather advantageous to the study of nitrogen poisoning phenomena.The physicochemical proper-ties of the four feedstocks are listed in Table2.The chemical nature of the feed determines its density and API gravity.Aromatics are much denser than paraffins with the same boiling point and therefore,will have a lower API gravity. Typical FCC feedstocks usually present densities around208–408API.In this case all the tested charges have specific gravities below this interval(178–188API)which means that the tested gasoils were rather heavy.The treated charge(B) measured density is very close to that of the initial charge(A). The density of the quinoline containing charges(C and D)was assumed not to be altered since the added amount was extremely small(<1wt%).The aniline point is the lowest temperature at which equal volumes of aniline(C6H5NH2)and the oil form a single phase. The aniline point correlates roughly with the amount and type of aromatic hydrocarbons in an oil sample.A low aniline point is indicative of high aromatics content,while a high aniline point is indicative of a lower aromatics content and larger paraffin concentration.The acid treatment causes a slight reduction in the aniline point and hence,the concentration of aromatics must not be changed to a great extent.The decrease can be owed to concentration effect:if aromatics do not precipitate,its concentration will be higher in the treated feed.The acid treatment causes a decrease of90%on the amount of basic nitrogen of the industrial feedstock which is quite remarkable.On the other hand only a45%decrease is observed for total nitrogen.Indeed,if the amount of basic nitrogen is subtracted,only15%of the non-basic nitrogen was removed from the charge.This means that acid removal treatment, besides being effective,is quite selective.In which concerns the sulfur amount,minor changes were observed after the acid treatment.The slight increase observed (Table2)can also be explained by concentration effect.On the other hand,the possibility that some of the sulfur contained in sulfuric acid did not precipitate could not be ruled out.The ASTM distillation produced very close results for the initial and acid treated samples.The treated feed distillation curve is even a little above that obtained for the initial industrial feedstock.In reality it is generally accepted that basic nitrogen molecules are lighter than non-basic nitrogen molecules,if only the basic nitrogen is removed the boiling point of the treated sample will increase.The Ramsbottom Carbon(RCR)residue test is intended to provide some indication of the extent of carbon residue which results from the combustion of a fuel.It measures the percentage of carbon residue by weight of crude oil.It increases with the acid treatment,even if the difference is not noteworthy.This could be related to a not100%efficient decantation or to the concentration effect referred previously.All the main physicochemical properties of the initial charge seem to be maintained after the denitrogenation treatment,with the obvious exception of the basic nitrogen content.This means that all the differences which will be reported for the catalytic cracking reaction of each one of four samples will be exclusively due to the presence of basic nitrogen compounds.3.2.ActivityAnalyzing Fig.1it becomes perfectly clear that the nitrogen removal procedure results in a strong increase in the reaction conversion.The treated charge(feedstock B:135ppm of basic N)is cracked much easier than the original gasoil(feedstock A: 1307ppm of basic N).For a CTO of5the difference isTable2Characterization of the four tested chargesProperties Feedstock identificationA B C a D aDensity(g cmÀ3)0.9520.9490.9520.949 API gravity178API188API188API178API Aniline point(8C)72.580.280.272.5 Basic N UOP269(ppm)130713513072479 Total N(wt%)0.3250.1780.2950.442 Total S(wt%)0.7120.8400.7120.840 RCR(wt%) 1.23 1.60 1.60 1.23 ASTM1170(8C)IBP291348348291 10%381411411381 30%431448448431 50%461474474461 70%494505505494 90%535561561535 FBP621––621a With exception of the total nitrogen and basic nitrogen contents,all the other properties were assumed to be equal to those of the parent charges(A and B)due to the very small amount of quinoline added(<1wt%).Fig.1.Conversion(wt)vs.CTO during catalytic cracking of feedstocks(&)A, (^)B,(~)C and(Â)D.G.Caeiro et al./Applied Catalysis A:General320(2007)8–15 10approximately10wt%while that for the highest CTO the difference diminishes to around5wt%.As already reported in previous papers,this phenomenon is due to poisoning of the Brønsted acid sites responsible for cracking[5,9,10,13,30].The difference is larger for low CTO;two facts can explain this behavior:(i)for high conversions the differences in the catalytic behavior tend to attenuate and/or(ii)for low CTO values the amount of base per mass of catalyst is higher and so, poisoning will be more pronounced.The charge which was prepared by addition of quinoline until1307ppm of basic nitrogen(feedstock C)presented conversion values very close to the ones of the original feed. This confirms that charges A and C present similar properties as it was previously discussed.This also means that the5–10wt% difference in the conversion of gasoils A and B is exclusively due to the greater amount of basic nitrogen present in thefirst sample.Lastly,the gasoil sample with the largest basic nitrogen concentration(feedstock D:2479ppm of basic N),as expected,exhibited the lowest conversion for all CTO values. This proves that unquestionably basic nitrogen molecules limit to a great extent the performance of catalytic cracking catalysts.The difference in conversion between feedstocks D and A(2–3wt%)is not as pronounced as between feedstocks A and B(5–10wt%)even if the difference in basic nitrogen is exactly the same(Nwt%(A)ÀNwt%(B)=Nwt%(D)ÀNwt%(A)=1172ppm).One possibility for this difference is that there is a saturation amount after which basic nitrogen is no longer retained in the catalyst.If one considers that all framework Al generate Brønsted sites able to retain a basic compound at5358C,the catalyst capacity should be $0.1wt%.In reality,during the injection of charge D for a CTO of5 (higher nitrogen to catalyst ratio),exactly4.5mg of basic nitrogen passes through the FCC catalyst.This corresponds to about0.05wt%of basic nitrogen which is only half of the theoretical saturation value.But obviously not all framework Al generate acid sites and,as a result,the saturation could be closer of0.05wt%than0.1wt%.Nevertheless there is an important setback to this reasoning:how to explain the57wt% conversion with charge D for a CTO=5?Three factors can explain this conversion:(i)at this temperature thermal cracking is non-negligible and corresponds to a conversion of at least10wt%(at CTO=5);(ii)the presented conversion values correspond to a mean between the start and the end of the injection,i.e.,the catalyst can be almost completely deactivated at the end of the test and reasonable conversion values can still be attained;(iii)the existence of a great heterogeneity of acid sites,each one with its own acid strength and activity.Indeed several studies reported the existence of several types of acid sites on H-USY zeolites[31–34],with different locations and catalytic activities.Poison molecules can interact preferentially with the stronger acid sites;if this occurs,after saturation of these stronger sites the poisoning effect will be less visible since the blocked sites are less active.3.3.Product distributionIt was clearly demonstrated that basic nitrogen decreases the conversion during gasoil cracking.However,it is equally important to assess if basic nitrogen has any effect on the product distribution of the cracking network reactions.In which concerns dry gas products(non condensable gases:H2,methane,ethane and ethylene),some differences can be detected by observation of Fig.2a.Fig.2b represents the hydrogen yield versus conversion for the four tested charges.It is noticeable that less hydrogen is produced with the low nitrogen gasoil whereas the charge with the highest concentration of basic nitrogen is that presenting the highest hydrogen yield.Undeniably there is an effect of nitrogen during one of the reactions responsible for hydrogen formation[35–38](protolysis,dehydrogenative coupling during coke formation reactions).Analogous results had already been reported[5].Other hypothesis is that the acid treatment caused precipitation of nickel containing porphyrine-type structures. In effect,nickel contributes significantly to dehydrogenation reactions and promotes coke and hydrogen formation[39].In fact,the catalytic properties of nickel are used in several industrial applications,including hydroprocessing catalysts. Two facts seem to rebut this theory:(i)the hydrogen yield is the same for charges A and C and only charge C suffered the acid treatment which means that nitrogen is the main responsible for the observed differences and(ii)the amount of Ni in the feed is too small(<30ppm)which corresponds to a maximal deposition of0.2ppm of Ni during the catalytic test (CTO=5).If one compares this amount with that already deposed in the equilibrium catalyst(3579ppm)it is obvious that the difference would never produce this difference in hydrogen yield.The production of methane and C2(ethane+ethene)also seems to be slightly enhanced by the presence of nitrogen (Fig.2c and d).A possible explanation is an increase in the protolytic cracking rate[35,36]which could also partially explain the increase in hydrogen yield.On the other hand,LPG,LCO and DO selectivities are not affected by the concentration of basic nitrogen in the feed (Fig.3).Conversely,the gasoline yield at iso-conversion increases for the low nitrogen feed(Fig.3b).The yield versus conversion curves present the common behavior for gasoil cracking reactions:there is an enhancement of LPG and gasoline selectivities(Fig.3a and b)with the increase of the conversion,whereas the LCO and DO yields decrease in the same proportion(Fig.3c and d).Hydrogen transfer reactions are one of the most important transformations in the catalytic cracking reaction network. Fig.4represents the evolution of iC4/C4=ratio with conversion.Hydrogen transfer reactions are favored by high acid densities and large available pore volume[40–44].The accumulation of nitrogen molecules causes a decrease in the amount of acid sites and possibly an enhanced pore blockage but,as it is visible in Fig.4,the extent of hydrogen transfer does not seem to be affected.G.Caeiro et al./Applied Catalysis A:General320(2007)8–1511Fig.2.(a)Dry Gas,(b)hydrogen,(c)methane and (d)C 2yields (wt)vs.conversion (wt)during the catalytic cracking of feedstocks (&)A,(^)B,(~)C and (Â)D.Fig.3.(a)LPG,(b)gasoline,(c)LCO and (d)DO yields (wt)vs.conversion (wt)during the catalytic cracking reaction of feedstocks (&)A,(^)B,(~)C and (Â)D.G.Caeiro et al./Applied Catalysis A:General 320(2007)8–1512In conclusion,at constant conversion,an increase in the feedstock basic nitrogen content results in a decrease in gasoline yield and an increase in hydrogen and dry gas yield.According to Sherzer and Mcarthur [7]some of these changes could be explained if one considered that,in order to maintain the conversion constant with a lower density of acid sites,the severity of the reaction has to be increased.The higher severity will allegedly result in more gaseous products and coke formed at the expense of gasoline.3.4.Coke formationFig.5a represents the coke yield as function of the catalyst conversion.It is evident that charges with higher nitrogen content also present larger coke yields.According to Barth et al.,this indicates that molecules containing nitrogen are important coke precursors and are preferentially retained [11].Indeed basic nitrogen molecules can be easily adsorbed onto the acid sites or participate in coke formation reactions due to their aromatic nature as it was reported in previous works with model molecules over H-USY zeolites [13].Nonetheless,if one considers the actual experimental coke contents versus conversion (Fig.5b),it is interesting to observe that no significant changes exist.Indeed the coke content in the catalyst is always close to 1wt%with the exception of the higher conversion for which the values increase to 1.3–1.4wt%.According to this data the amount of coke remains almost unchanged for all four charges.In reality,for high nitrogen feeds more catalyst is necessary to the same inlet rate of gasoil in order to achieve an equal conversion and,since the amount of coke per mass of zeolite is the same,coke yields are larger.As an example,the amount of coke formed after reaction with charge A and a CTO of 8(1wt%)is exactly the same that with charge B with a CTO of 5,the conversion for the two tests was also the same (69wt%)but conversely,the coke yields are,respectively,9.0and 5.5wt%due to the CTO difference.Previously it was proposed that one of the reasons for the increase in the hydrogen yield was the enhancement on the production of aromatics in presence of basic nitrogen.In fact several coke formation reactions produce hydrogen for which itis not surprising that the two yields are correlated to some extent.Furthermore the higher gasoline yield obtained for the low nitrogen feed can also be compensated by the lower coke yield measured for this charge.This means that the additional gasoline production is caused by a lower consumption of gasoline range aromatics and/or olefins to produce coke.Fig.6represents the sum of the hydrogen,gasoline and coke yields for all four charges.No significant changes are detected which implies that definitely,at constant conversion,the increase in the produced amounts of coke and hydrogen occurs attheFig.4.Isobutane/butenes ratio vs.conversion (wt)during the catalytic cracking reaction of feedstocks (&)A,(^)B,(~)C and (Â)D.Fig.5.(a)Coke yields (wt)vs.conversion (wt).(b)Carbon contents in the catalyst vs.conversion during the catalytic cracking reaction of feedstocks (&)A,(^)B,(~)C and (Â)D.Fig.6.Sum of the hydrogen,gasoline and coke yields (wt)vs.conversion (wt)during the catalytic cracking of feedstocks (&)A,(^)B,(~)C and (Â)D.G.Caeiro et al./Applied Catalysis A:General 320(2007)8–1513expense of gasoline.All these differences are due to the increase in the catalyst to oil ratio necessary to obtain equal conversions.Just about all the removed coke after the HF treatment was insoluble in dichloromethane.Even so,traces of alkylpyrenes and quinoline were found by GC–MS coupling for some of the charges.Elemental analysis of the insoluble fraction of coke was not conclusive.Indeed,no nitrogen was found in the catalysts coked for a CTO of5for all4feedstocks.This does not mean that nitrogen does not intervene in coke formation reactions;indeed,this can be due to limitations inherent to the used experimental methodology.To begin with,the dissolution process is not completely effective,since some of the catalyst components(e.g.alumina)are not completely destroyed by the HF treatment.In fact,the elemental analysis showed that the recovered solid phase consisted of only6–8wt%of carbon and 0.35–0.55wt%of hydrogen(H/C ratio of approximately 0.75mol/mol).Also,the detection limit of the used experi-mental apparatus is0.3wt%.Although it was impossible to determine the real nitrogen content in insoluble coke,an attempt was made to estimate a theoretical value for comparison purposes.For the samples obtained at CTO5,total nitrogen contents in the catalyst between0.04wt%(feedstock B)and0.09wt%(feedstock D) are expected.Since the solid fraction recovered byfiltration in the extraction procedure has six to eight times more carbon,a concentration effect of this magnitude is also expected in the nitrogen content.Based on these assumptions,if all nitrogen molecules are retained in insoluble coke,contents of0.25wt% (below detection limit)and0.6wt%are expected to be found for feedstocks B and D,respectively.These results indicate that for charge D at least50wt%of the nitrogen molecules present in the feed are not retained in the catalyst in the form of insoluble coke.Even so,the intervention of nitrogen molecules in coke formation has been reported for commercial spent RFCC catalyst samples[45].4.ConclusionsSeveral important conclusions can be drawn from the results obtained throughout this research work.First,acid treatments are quite effective and selective on the basic nitrogen removal of FCC charges.Nitrogen basic compounds have a strong influence in the performance of catalytic cracking catalysts. The poison molecules adsorb on the acid sites responsible by the reaction decreasing overall conversion.Differences of5–10wt%are observed between gasoils with basic nitrogen contents differing of1172ppm.Besides the decrease in activity,changes are observed in product distribution.At constant conversion,an increase in the basic nitrogen content of the feed results in a decrease in gasoline yield and an increase in hydrogen and coke yields.The increase in the produced amount of coke and hydrogen is done at the expense of gasoline.These differences in product distribution are due to the different CTO values necessary to obtain equal conversions, and not to an actual increase in the rate of coke formation due to basic nitrogen.Analysis of the coke retained in the catalyst indicates that,at least for the high nitrogen feedstocks,some nitrogen molecules are not adsorbed on the acid sites and do not act as precursors to (insoluble)coke formation.AcknowledgmentsG.Caeiro and P.Matias express their gratitude to the Fundac¸a˜o para a Cieˆncia e Tecnologia(FCT)for its PhD grant (ref.SFRH/BD/13411/2003and SFRH/BD/19843/2004). Besides,all authors thank the Fundac¸a˜o para a Cieˆncia e Tecnologia(FCT)forfinancing the project ref.POCI/EQU/ 58550/2004.References[1]J.Thomas,F.Degnan,Top.Catal.13(2000)349.[2]C.R.Marcilly,Top.Catal.13(2000)357.[3]P.A.Jacobs,C.F.Heylen,J.Catal.34(1974)267.[4]C.F.Heylen,P.A.Jacobs,J.B.Uytterhoeven,J.Catal.43(1976)99.[5]J.Scherzer,D.P.Mcarthur,Oil Gas J.84(1986).[6]R.Hughes,G.J.Hutchings,C.L.Koon,B.McGhee,C.E.Snape,D.Yu,Appl.Catal.A144(1996)269.[7]J.Scherzer,D.P.Mcarthur,Abstracts Papers Am.Chem.Soc.196(1988).[8]ls,E.R.Boedekker,A.G.Oblad,J.Am.Chem.Soc.72(1950)1554.[9]T.C.Ho,A.R.Katritzky,S.J.Cato,Ind.Eng.Chem.Res.31(1992)1589.[10]A.Corma,V.Fornes,J.B.Monton,A.V.Orchilles,Ind.Eng.Chem.Res.26(1987)882.[11]J.-O.Barth,A.Jentys,J.A.Lercher,Ind.Eng.Chem.Res.43(2004)2368.[12]F.S.Rosser,M.W.Schnaith,P.D.Walker,AIChE Annual Meeting Con-ference Proceedings,Des Plaines,Illinois,USA,2004.[13]G.Caeiro,P.Magnoux,J.M.Lopes,F.R.Ribeiro,Appl.Catal.A292(2005)189.[14]A.Corma,F.A.Mocholı´,Appl.Catal.A84(1992)31.[15]C.-M.Fu,A.M.Schaffer,Ind.Eng.Chem.Product Res.Dev.24(1985)68.[16]R.Hughes,G.Hutchings,C.L.Koon,B.McGhee,C.E.Snape,in:ACSpreprints,Division of Petrol.Chem.39(1994)379.[17]S.E.V oltz,D.M.Nace,M.J.Solomon,V.W.Weekman,Eng.Chem.Process Des.Dev.11(1972)261.[18]S.M.Jacob,B.Gross,S.E.V oltz,V.W.Weekman,AlChE J.22(1976)701.[19]R.F.Schwab,K.Baron,2nd Katalistiks FCC Symposium ConferenceProceedings,Amsterdam,1981.[20]L.D.Messrs,J.Scherzer,D.P.McArthur,NPRA Meeting ConferenceProceedings,1986.[21]G.D.Hobson,Modern Petroleum Technology.Part I,John Wiley andSons,1992.[22]R.Long,F.Caruso,Patent US4,419,219(1983)assigned to EXXONResearch Engineering Co.[23]R.Smith,Patent US4,090,951(1978)assigned to Atlantic Richfield Co.[24]D.Hitzman,Patent US4,518,489(1985)assigned to Phillips PetroleumCo.[25]D.Curtin,Patent US4,287,051(1981)assigned to Atlantic Richfield Co.[26]Patent4,081,351(1978)assigned to Mobil Oil Corporation.[27]E.Moreira,C.Baptista,C.Pereira,J.Vieira,Patent BR302,325(2005)assigned to Petro´leo Brasileiro S.A.[28]C.Pereira,E.Moreira,B.Rulf,Patent WO9,803,585-1(2000)assigned toPetro´leo Brasileiro S.A.[29]P.Magnoux,P.Roger,C.Canaff,V.Fouche´,N.S.Gnep,M.Guisnet,Stud.Surf.Sci.Catal.34(1987)317.[30]G.Caeiro,P.Magnoux,P.Ayrault,J.M.Lopes,F.R.Ribeiro,Chem.Eng.J.120(2006)43.[31]H.S.Cerqueira,P.Ayrault,J.Datka,M.Guisnet,Micropor.Mesopor.Mater.38(2000)197.[32]M.A.Makarova,J.Dwyer,J.Phys.Chem.97(1993)6337.G.Caeiro et al./Applied Catalysis A:General320(2007)8–15 14。
Nitrogen Asphyxiation Bulletin Training Presentati
• Additional nitrogen (lower oxygen) cannot be detected by the sense of smell.
Laboratories
Miscellaneous (including medical facilities and transportation)
Statistics on Incidents (cont’d)
• The majority of incidents occurred in and around confined spaces, though several incidents occurred in “open” areas, including inside buildings and outdoors near equipment.
Confined Spaces
An operator was conducting a flammable gas test on a line connected to a flare in order to issue a hot work permit.
• The operator issued a permit that required an air-supplied respirator.
The Hazards of Nitrogen Asphyxiation
US Chemical Safety and Hazard Investigation Board
缺氧诱导因子-1靶基因参与生酮饮食提高大脑中动脉闭塞模型小鼠脑缺血耐受作用
缺氧诱导因子-1靶基因参与生酮饮食提高大脑中动脉闭塞模型小鼠脑缺血耐受作用国敏;崔梅;董强【期刊名称】《转化医学杂志》【年(卷),期】2016(0)1【摘要】Objective To explore the effects of ketogenic diet on middle cerebral artery occ-lusion ( MCAO ) mice and the role of hypoxia inducible factor-1 ( HIF-1 ) target genes in this process. Methods C57BL/6 mice were randomly allocated into four groups: standard diet group, high carbohydrate diet group, ketogenic diet group and control group. Mice of the 3 intervention groups were fed with corresponding diets for 3 weeks and were afterwards made into MCAO mice models. Control group was fed with standard diet for 3 weeks without MCAO treatment. Stroke vo-lume was measured by 2,3,5-triphenyl tetrazolium chloride ( TTC) staining. Neurological function was accessed by Longa scoring method. Polymerase chain reaction ( PCR) was used to detect mRNA expression quantity of HIF-1 downstream target genes including erythropoietin ( EPO) , vascular en-dothelial growth factor ( VEGF ) , glucose transport 1 ( GLUT1 ) and monocarboxylic transporter 4 ( MCT4) in the ischemic region. Results Compared with the other 3 groups, ketogenic diet group showed smaller stroke volume, better neurological score and higher mRNA expression quantity of HIT-1 downstream target genes. Conclusion Ketogenic dietmay improve brain ischemic tolerance of MCAO mice through up-regulation of HIF-1 target genes.%目的：探究生酮饮食对大脑中动脉闭塞( middle cerebral artery occlusion,MCAO)模型小鼠的作用及缺氧诱导因子-1靶基因参与机制。