Search scope:
排序： Display mode:
Exploration for the Synthesis Route of Superior High Energy Density Materials (SHEDM)
Yu Yongzhong
Strategic Study of CAE 1999, Volume 1, Issue 2, Pages 91-94
The development of high explosives could be reviewed as TNT, RDX, and HMX as three historical stages, and now we are coming in the fourth stage which marked by the appearance of CL-20. However, the increment of energy denicty of the CL-20 is only about 10% greater than that of HMX.
For the needs of the improvement of the weapon systems in the next century, it is necessary to search and develop the superior high energy density materials, and it would be some quite new classes of substance.
Performance of nitrogen cluster, such as octaazacubane N8, was calculated by quantum chemists and demonstrated its remarkable prospects, which is represented as an example of the imaginary SHEDM. And it was emphasized that new allotropic forms of nitrogen Nn would be the most promissing substance as SHEDM. Recently N5+ was found in the MS, and it is already prepared as a salt by Christe.
Nitrogen polymer Nn, in which n is a large number and N atoms are connected by covalent bonds in a three dimentioal net structure just as a polymer, is should be paid the greatest attention and would become the most powerful SHEMD in the next century.
Keywords： HEDM nitrogen cluster nitrogen polymer
Luo Qijin,Chen Jianyu,Wang Zhenxing,Pang Zhihua,Ye Wansheng
Strategic Study of CAE 2014, Volume 16, Issue 8, Pages 88-92
According to the request of emission reduction of industry and total ammonia amount control in 12th five-year plan periods,this paper investigates the comprehensive evaluation methods of emission reduction technologies---a case study of nitrogen fertilizer. Aiming at the problems of domestic environmental technologies evaluation methods are mainly based on experts’qualitative estimate and lack of comprehensive evaluation methods, cost benefit analysis and analytic hierarchy process with grey comprehensive evaluation method were combined,a kind of evaluation method of best available technology for emission reduction of ammonia in nitrogen fertilizer industry was developed．The modeling process of the mathematical model of analytic and grey integrated evaluation method was provided with an application example analyzed．
Keywords： ammonia total amount control comprehensive evaluation
Fitting on the Earth: Challenges of Carbon and Nitrogen Cycle to Preserve the Habitability of the Planet Views & Comments
Robert Socolow
Engineering 2016, Volume 2, Issue 1, Pages 21-22 doi: 10.1016/J.ENG.2016.01.012
Economic Development Models of Gas Condensate Reservoir
Liu Tingyuan
Strategic Study of CAE 2001, Volume 3, Issue 3, Pages 85-91
Liquid condensate is an important product of gas condensate reservoir, and its recovery should be both efficient and economic. This paper discusses economic development models of all kinds during the last two decades in the engineering field of gas condensate reservoirs, including reinjection with 75% dry gas recycling, dumpflooding of gas, nitrogen injection, water injection, water and gas alternating injection, C〇2 injection, etc. The results of the study indicate that these development models will be more effective than conventional pressure depletion methods and will be adaptable to complex cases of surface-underground gas condensate reservoirs.
Keywords： gas condensate reservoir development model gas injection nitrogen injection water injection CO 2 injection economic
Zihao Zhao, Zihao Wang, Jialuo Yuan, Jun Ma, Zheling He, Yilan Xu, Xiaojia Shen, Liang Zhu
Engineering 2021, Volume 7, Issue 2, Pages 195-202 doi: 10.1016/j.eng.2020.07.027
The problem of effluent total nitrogen (TN) at most of the wastewater treatment plants (WWTPs) in China is important for meeting the related water quality standards, even under the condition of high energy consumption. To achieve better prediction and control of effluent TN concentration, an efficient prediction model, based on controllable operation parameters, was constructed in a sequencing batch reactor process. Compared with previous models, this model has two main characteristics: ① Superficial gas velocity and anoxic time are controllable operation parameters and are selected as the main input parameters instead of dissolved oxygen to improve the model controllability, and ② the model prediction accuracy is improved on the basis of a feedforward neural network (FFNN) with algorithm optimization. The results demonstrated that the FFNN model was efficiently optimized by scaled conjugate gradient, and the performance was excellent compared with other models in terms of the correlation coefficient (R). The optimized FFNN model could provide an accurate prediction of effluent TN based on influent water parameters and key control parameters. This study revealed the possible application of the optimized FFNN model for the efficient removal of pollutants and lower energy consumption at most of the WWTPs.
Keywords： Feedforward neural network (FFNN) Algorithms Controllable operation parameters Sequencing batch reactor (SBR) Total nitrogen (TN)
Shi-Chao Qi, Xiao-Jie Lu, Yin-Cong Lou, Rui Zhou, Ding-Ming Xue, Xiao-Qin Liu, Lin-Bing Sun
Engineering 2022, Volume 16, Issue 9, Pages 154-161 doi: 10.1016/j.eng.2021.07.031
It is common that a proof-of-concept of a desired reaction, which might generate materials with new functions or application potential, is eventually proved impracticable or commercially unfeasible. Considerable efforts have been made but wasted in searching for unknown reaction conditions in solvent environments because it was believed that the activity of reactants can be enhanced to facilitate reactions by dissolving them in solvents. However, an abnormal case was discovered in this study. A desired copolymerization reaction between 1,3,5-tris(chloromethyl)-2,4,6-trimethylbenzene and melamine was confirmed to be impracticable under various solvent conditions; however, it was successfully implemented using a solvent-free method. Using first-principle calculations and molecular dynamics simulations, two decisive factors that the reaction in solvents cannot possess, namely the reaction equilibrium being pushed by the timely release of by-products and the confined thermal motions of the activated monomer molecules in the solid phase, were demonstrated to make the copolymerization successful in the solvent-free method. Owing to the high aromaticity and azacyclo-content, the as-synthetic copolymer exhibited good application potential as a precursor to fabricate N-doped porous carbons with satisfactory carbon yields, ideal N contents, desired textural properties, and competitive CO2 capture abilities compared to other representative counterparts reported recently.
Keywords： Solvent-free method Solvent effect Copolymerization N-doped porous carbon
Analysis on the Amount and Utilization of Manure in Livestock and Poultry Breeding in China
Shuxia Wu, Hongbin Liu, Hongkun Huang, Qiuliang Lei, Hongyuan Wang, Limei Zhai, Shen Liu, Ying Zhang, Yu Hu
Strategic Study of CAE 2018, Volume 20, Issue 5, Pages 103-111 doi: 10.15302/J-SSCAE-2018.05.016
Unreasonable discharge of manure from livestock and poultry breeding is a main source of agricultural non-point source pollution in China, but the manure is also a potential resource. How to achieve the best resource utilization of livestock manure and reduce environmental pollution has become a major problem that must be solved in the sustainable development of China’s breeding industry. In this paper, the pollutant discharge coefficient method is used to calculate the amount of manure produced by livestock and poultry breeding in China, and the current situation and problems of its resource utilization are analyzed.
Extreme Energetic Materials at Ultrahigh Pressures Perspective
Ho-Kwang Mao, Cheng Ji, Bing Li, Gang Liu, Eugene Gregoryanz
Engineering 2020, Volume 6, Issue 9, Pages 976-980 doi: 10.1016/j.eng.2020.07.010
Owing to their extremely high energy density, single-bonded polymeric nitrogen and atomic metallic hydrogen are generally regarded as the ultimate energetic materials. Although their syntheses normally require ultrahigh pressures of several hundred gigapascals (GPa), which prohibit direct materials application, research on their stability, metastability, and fundamental properties are valuable for seeking extreme energetic materials through alternative synthetic routes. Various crystalline and amorphous polymeric nitrogens have been discovered between 100 and 200 GPa. Metastability at ambient conditions has been demonstrated for some of these phases. Cubic-gauche and black-phosphorus polymorphs of single-bonded nitrogen are two particularly interesting phases. Their large hystereses warrant further application-inspired basic research of nitrogen. In contrast, although metallic hydrogen contains the highest-estimated energy density, its picosecond lifetime and picogram quantity make its practical material application impossible at present. "Metallic hydrogen" remains a curiosity-driven basic research pursuit focusing on the pressure-induced evolution of the molecular hydrogen crystal and its electronic band structure from a low-density insulator with a very wide electronic band gap to a semiconductor with a narrow gap to a dense molecular metal and atomic metal and eventually to a previously unknown exotic state of matter. This great experimental challenge is driving relentless advancement in ultrahighpressure science and technology.
Keywords： Energetic materials Ultrahigh pressure Polymeric nitrogen Metallic hydrogen
Plant Traits for Phytoremediation in the Tropics Article
Xiangting Cleo Chen, Liling Huang, Tze Hsien Agnes Chang, Bee Lian Ong, Say Leong Ong, Jiangyong Hu
Engineering 2019, Volume 5, Issue 5, Pages 841-848 doi: 10.1016/j.eng.2019.07.019
Water is a limited and valuable resource. Singapore has four national sources of water supply, one of which is natural precipitation. Pollutants collected in stormwater runoff are deposited into drainage systems and reservoirs. Major nutrient pollutants found in local stormwater runoff include nitrate and phosphate, which may cause eutrophication. Bioretention systems are efficient in removing these pollutants in the presence of plants. This paper discusses plant traits that can enhance the phytoremediation of nutrient pollutants in stormwater runoff for application in bioretention systems. The plant species studied showed variations in chlorophyll florescence, leaf greenness, biomass production, and nitrate and phosphate removal. In general, dry biomass was moderately correlated to nitrate and phosphate removal (r = 0.339–0.501). Root, leaf, and total dry biomass of the native tree species showed a moderate to strong correlation with nitrate removal (r = 0.811, 0.657, and 0.727, respectively). Leaf dry biomass of fastgrowing plants also showed a moderate to strong relationship with the removal of both pollutants (r = 0.707 and 0.609, respectively). Root dry biomass of slow-growing plants showed a strong relationship with phosphate removal (r = 0.707), but the correlation was weaker for nitrate removal (r = 0.557). These results are valuable for choosing plants for application in bioretention systems.
Keywords： Nitrogen Phosphorus Plant traits Bioretention system Stormwater Tropical plant Nutrient pollutant Native plants
Wu Haisuo,Xu Ming,Zhang Minjian,Liu Weijing,Yu Xuemin,Wu Wei
Strategic Study of CAE 2010, Volume 12, Issue 6, Pages 54-59
Pilot-scale & demonstration project study of the treatment of printing and dyeing wastewater was carried out using the combined process of anaerobic (hydrolysis)-aerobic-advanced treatment. The result of Pilot-scale study indicates:the total removal efficiency of the COD, color, NH3-N, TN, TP of the system were 93.2 %, 93.9 %, 90.2 %, 70.8 %, 96.3 % respectively, anaerobic (hydrolysis) is vital to COD & color degradation, the removal efficiency of the COD & color were 48.1 %, 75.7 %, respectively, The A/O(PACT)is vital to NH3-N & TN degradation, the coagulation treatment could effectively degrade the TP. The effluent of Pilot-scale & demonstration project could satisfy 《Discharge Standard of Main Water Pollutants for Municipal Wastewater Treatment Plant & Key Industries of Taihu Area》(DB32/1072-2007).
Keywords： Taihu Area printing and dyeing wastewater nitrogen and phosphorus removal demonstration project
Naga Raju Maddela, Zhihao Gan, Yabing Meng, Fuqiang Fan, Fangang Meng
Engineering 2022, Volume 17, Issue 10, Pages 196-206 doi: 10.1016/j.eng.2021.07.024
Nitrogen removal is a critical process in water treatment plants (WTPs) and wastewater treatment plants (WWTPs). The recent discovery of a novel bacterial process, complete ammonia oxidation (comammox, CMX), has refuted a century-long perception of the two-step conversion of NH3 to NO3–. Compared with canonical nitrifiers, CMX bacteria offer undeniable advantages, such as a high growth yield propensity and adaptability to nutrient- and growth-limiting conditions, which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment. As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment, this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater. We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels. We focused on the distribution of CMX bacteria in engineered systems, niche differentiation, co-occurrence and interactions with canonical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology. Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided. The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated, and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs. Finally, we summarized future directions of research that are imperative in improving the understanding of CMX biology.
Keywords： Comammox bacteria Wastewater treatment Nitrogen removal Micropollutant degradation Reactor operation
Yuchuan Fan, Jie Zhuang, Michael Essington, Sindhu Jagadamma, John Schwartz, Jaehoon Lee
Engineering 2023, Volume 21, Issue 2, Pages 214-226 doi: 10.1016/j.eng.2022.08.017
Denitrifying bioreactors (DNBRs) are widely used to reduce excess nitrate from agricultural drainage. Their performance depends on the physical and chemical properties of the substrate. Common substrate types have been partly reviewed in previous studies. However, few studies have attempted to determine a generalized pattern for the role of substrate type in nitrate removal. This study summarizes 41 types of
substrates using a dataset collected from 63 peer-reviewed articles, which include 219 independent DNBR units. The substrates are classified into four groups: ① natural carbon (NC), such as woodchips; ② non-natural carbon (NNC), such as biodegradable polymers (e.g., polycaprolactone (PCL) and waste products (e.g., cardboard); ③ inorganic materials (IMs), such as non-carbon materials (e.g., iron oxide); and④multiple materials (MMs), such as a mixture of the above materials. These materials are compared and evaluated through a meta-analysis of nitrate removal rate (NRR; N removal (g∙m–3∙d–1)) and nitrate removal efficiency (NRE). This study reviews substrate performance (NRR and NRE), potential mechanisms, pollution swapping, and cost analysis. Our analysis indicates that woodchips and corncobs are the most cost-effective substrates among NCs. In a comparison of all the studied substrates, MM substrates are recommended as the optimal substrates, especially woodchip-based and corncob-based substrates, which have great potential for improvement. This analysis can assist in optimizing the design of DNBRs to meet the environmental, economic, and practical requirements of users.
Keywords： Denitrifying bioreactor Substrate Nitrate removal Meta-analysis Environmental impact Cost analysis
Zhiyong Wang, Zhijian Zhao, Jesse Baucom, Dan Wang, Liming Dai, Jian-Feng Chen
Engineering 2020, Volume 6, Issue 6, Pages 680-687 doi: 10.1016/j.eng.2019.12.018
Herein, we report on the effect of a high gravity field on metal-free catalytic reduction, taking the nitrobenzene (NB) reduction and methylene blue (MB) degradation as model reactions in a highgravity rotating tube reactor packed with three-dimensional (3D) nitrogen-doped graphene foam (NGF) as a metal-free catalyst. The apparent rate constant (kapp) of the metal-free catalytic reduction of NB in the rotating tube reactor under a high gravity level of 6484g (g = 9.81 m·s-2) was six times greater than that in a conventional stirred reactor (STR) under gravity. Computational fluid dynamics (CFD) simulations indicated that the improvement of the catalytic efficiency was attributed to the much higher turbulent kinetic energy and faster surface renewal rate in the high-gravity tube reactor in comparison with those in a conventional STR. The structure of the 3D metal-free catalysts was stable during the reaction process under a high gravity field, as confirmed by X-ray photoelectron spectroscopy (XPS) and Raman spectra. In the other model reaction, the rate of MB degradation also increased as the high gravity level increased gradually, which aligns with the result for the NB catalytic reduction system. These results demonstrate the potential to use a high-gravity rotating packed tube reactor for the process intensification of metal-free catalytic reduction reactions.
Keywords： High-gravity technology Process intensification Metal-free catalysts Carbon nanomaterials Catalytic reduction
Praewpilin Kangvansura, Ly May Chew, Chanapa Kongmark, Phatchada Santawaja, Holger Ruland, Wei Xia, Hans Schulz, Attera Worayingyong, Martin Muhler
Engineering 2017, Volume 3, Issue 3, Pages 385-392 doi: 10.1016/J.ENG.2017.03.013
Nitrogen-doped carbon nanotubes (NCNTs) were used as a support for iron (Fe) nanoparticles applied in carbon dioxide (CO2) hydrogenation at 633 K and 25 bar (1 bar = 105 Pa). The Fe/NCNT catalyst promoted with both potassium (K) and manganese (Mn) showed high performance in CO2 hydrogenation, reaching 34.9% conversion with a gas hourly space velocity (GHSV) of 3.1 L·(g·h)−1. Product selectivities were high for olefin products and low for short-chain alkanes for the K-promoted catalysts. When Fe/NCNT catalyst was promoted with both K and Mn, the catalytic activity was stable for 60 h of reaction time. The structural effect of the Mn promoter was demonstrated by X-ray diffraction (XRD), temperature-programmed reduction (TPR) with molecular hydrogen (H2), and in situ X-ray absorption near-edge structure (XANES) analysis. The Mn promoter stabilized wüstite (FeO) as an intermediate and lowered the TPR onset temperature. Catalytic ammonia (NH3) decomposition was used as an additional probe reaction for characterizing the promoter effects. The Fe/NCNT catalyst promoted with both K and Mn had the highest catalytic activity, and the Mn-promoted Fe/NCNT catalysts had the highest thermal stability under reducing conditions.
Keywords： CO2 hydrogenation Iron catalyst Nitrogen-doped carbon nanotubes Manganese promoter Potassium promoter
Wei Miao, Yijie Wang, Ying Liu, Hehe Qin, Chengcheng Chu, Shun Mao
Engineering 2023, Volume 25, Issue 6, Pages 214-221 doi: 10.1016/j.eng.2021.12.016
In-situ photocatalytic H2O2 production has been receiving increasing attention in recent years for sustainable H2O2 synthesis. Graphitic carbon nitride (g-C3N4) is regarded as one of the most promising semiconductor photocatalysts for H2O2 evolution. Introducing N defects in g-C3N4 has been proved to be an effective strategy to enhance photocatalytic activity. However, the photocatalytic mechanism of the N vacancies is ambiguous and different types of N vacancies in g-C3N4 may exhibit different effects on photocatalytic activity. Herein, we develop a facile sodium persulfate eutectic polymerization method to prepare the g-C3N4 with abundant three coordinate nitrogen (N3C) vacancies. This type of nitrogen vacancy has not been studied in g-C3N4 for photocatalytic H2O2 production. Our results showed that the introduction of N3C vacancies in the g-C3N4 successfully broadened the light absorption range, inhibited the photoexcited charge recombination with enhanced O2 adsorption to promote oxygen activation. The photocatalytic H2O2 evolution from the N3C-rich g-C3N4 is 4.5 times higher than that of the pristine g-C3N4. This study demonstrates a novel strategy to introduce N3C vacancies in g-C3N4, which offers a new method to develop active catalysts for photocatalytic H2O2 evolution.
Keywords： Carbon nitride N3C vacancy Hydrogen peroxide evolution Photocatalysis Persulfate
Title Author Date Type Operation
Exploration for the Synthesis Route of Superior High Energy Density Materials (SHEDM)
Yu Yongzhong
Journal Article
The evaluation method of best available technology for emission reduction of ammonia in nitrogen fertilizer industry
Luo Qijin,Chen Jianyu,Wang Zhenxing,Pang Zhihua,Ye Wansheng
Journal Article
Fitting on the Earth: Challenges of Carbon and Nitrogen Cycle to Preserve the Habitability of the Planet
Robert Socolow
Journal Article
Development of a Novel Feedforward Neural Network Model Based on Controllable Parameters for Predicting Effluent Total Nitrogen
Zihao Zhao, Zihao Wang, Jialuo Yuan, Jun Ma, Zheling He, Yilan Xu, Xiaojia Shen, Liang Zhu
Journal Article
Implementing An “Impracticable” Copolymerization to Fabricate A Desired Polymer Precursor for N-doped Porous Carbons
Shi-Chao Qi, Xiao-Jie Lu, Yin-Cong Lou, Rui Zhou, Ding-Ming Xue, Xiao-Qin Liu, Lin-Bing Sun
Journal Article
Analysis on the Amount and Utilization of Manure in Livestock and Poultry Breeding in China
Shuxia Wu, Hongbin Liu, Hongkun Huang, Qiuliang Lei, Hongyuan Wang, Limei Zhai, Shen Liu, Ying Zhang, Yu Hu
Journal Article
Extreme Energetic Materials at Ultrahigh Pressures
Ho-Kwang Mao, Cheng Ji, Bing Li, Gang Liu, Eugene Gregoryanz
Journal Article
Plant Traits for Phytoremediation in the Tropics
Xiangting Cleo Chen, Liling Huang, Tze Hsien Agnes Chang, Bee Lian Ong, Say Leong Ong, Jiangyong Hu
Journal Article
Research on standard upgrading technologies of urban wastewater treatment plants for pollutions dominated by printing and dyeing wastewater in Taihu Lake Basin
Wu Haisuo,Xu Ming,Zhang Minjian,Liu Weijing,Yu Xuemin,Wu Wei
Journal Article
Occurrence and Roles of Comammox Bacteria in Water and Wastewater Treatment Systems: A Critical Review
Naga Raju Maddela, Zhihao Gan, Yabing Meng, Fuqiang Fan, Fangang Meng
Journal Article
Global Significance of Substrates for Nitrate Removal in Denitrifying Bioreactors Revealed by Meta-Analysis
Yuchuan Fan, Jie Zhuang, Michael Essington, Sindhu Jagadamma, John Schwartz, Jaehoon Lee
Journal Article
Nitrogen-Doped Graphene Foam as a Metal-Free Catalyst for Reduction Reactions under a High Gravity Field
Zhiyong Wang, Zhijian Zhao, Jesse Baucom, Dan Wang, Liming Dai, Jian-Feng Chen
Journal Article
Effects of Potassium and Manganese Promoters on Nitrogen-Doped Carbon Nanotube-Supported Iron Catalysts for CO2 Hydrogenation
Praewpilin Kangvansura, Ly May Chew, Chanapa Kongmark, Phatchada Santawaja, Holger Ruland, Wei Xia, Hans Schulz, Attera Worayingyong, Martin Muhler
Journal Article
京公网安备 11010502051620号
