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Antibiotic resistome of : molecular determinants for the emergence of drug resistance

《医学前沿(英文)》 2021年 第15卷 第5期   页码 693-703 doi: 10.1007/s11684-020-0777-6

摘要: Resistome is a cluster of microbial genes encoding proteins with necessary functions to resist the action of antibiotics. Resistome governs essential and separate biological functions to develop resistance against antibiotics. The widespread clinical and nonclinical uses of antibiotics over the years have combined to select antibiotic-resistant determinants and develop resistome in bacteria. At present, the emergence of drug resistance because of resistome is a significant problem faced by clinicians for the treatment of Salmonella infection. Antibiotic resistome is a dynamic and ever-expanding component in Salmonella. The foundation of resistome in Salmonella is laid long before; therefore, the antibiotic resistome of Salmonella is reviewed, discussed, and summarized. We have searched the literature using PubMed, MEDLINE, and Google Scholar with related key terms (resistome, Salmonella, antibiotics, drug resistance) and prepared this review. In this review, we summarize the status of resistance against antibiotics in S. typhi, highlight the seminal work in the resistome of S. typhi and the genes involved in the antibiotic resistance, and discuss the various methods to identify S. typhi resistome for the proactive identification of this infection and quick diagnosis of the disease.

关键词: S. typhi     antibiotic resistance     mechanism     resistome     identification methods    

Exergy analysis and simulation of a 30MW cogeneration cycle

Nikhil Dev, Samsher, S. S. Kachhwaha, Rajesh Attri

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 169-180 doi: 10.1007/s11465-013-0263-9

摘要:

Cogeneration cycle is an efficient mean to recover the waste heat from the flue gases coming out of gas turbine. With the help of computer simulation, design parameters may be selected for the best performance of cogeneration cycle. In the present work a program is executed in software EES on the basis of mathematical modelling described in paper to study cogeneration cycle performance for different parameters. Results obtained are compared with the results available in literature and are found in good agreement with them. Real gas and water properties are inbuilt in the software. Results show that enthalpy of air entering the combustion chamber is higher than that of the flue gases at combustion chamber outlet. For different operative conditions, energy and exergy efficiencies follow similar trends; although, exergy efficiency values are always lower than the corresponding energy efficiency ones. From the results it is found that turbine outlet temperature (TIT) of 524°C is uniquely suited to efficient cogeneration cycle because it enables the transfer of heat from exhaust gas to the steam cycle to take place over a minimal temperature difference. This temperature range results in the maximum thermodynamic availability while operating with highest temperature and highest efficiency cogeneration cycle. Effect of cycle pressure ratio (CR), inlet air temperature (IAT) and water pressure at heat recovery steam generator (HRSG) inlet on the 30 MW cogeneration cycle is also studied.

关键词: Cogeneration cycle     air compressor     HRSG     gas turbine     regenerator     CR     IAT    

香蕉假茎作为吸附剂用于水溶液中铅离子去除的条件优化、动力学与吸附平衡研究 Article

Shridhar S. Bagali, Bychapur S. Gowrishankar, Aashis S. Roy

《工程(英文)》 2017年 第3卷 第3期   页码 409-415 doi: 10.1016/J.ENG.2017.03.024

摘要:

香蕉假茎粉末等天然吸附剂对于去除废水中的重金属元素具有非常重要的作用。现有的去除重金属元素的常规方法难以满足水资源循环和化学工业的需求。本文论证了利用天然物质处理废水的可能性。利用环境扫描电子显微镜(ESEM) 和傅里叶变换红外(FTIR) 光谱学分析方法,研究了香蕉假茎粉末吸附铅离子前后的变化。实验采用批处理方法研究了水溶液中铅离子去除的效果。通过改变初始pH 值、吸附剂用量、初始铅离子浓度、吸附时间等参数,研究了吸附动力学的影响。结果表明,在水溶液pH 值为5.5 时,香蕉假茎粉末达到零电荷点。采用吸附等温线和动力学模型分析实验数据,采用朗缪尔吸附等温式拟合铅离子在香蕉假茎粉末表面的吸附作用。实验表明,香蕉假茎粉末对铅离子的吸附量为34.21 mg·g−1,与拟二级动力学模型相匹配。此外,采用响应面分析法确定了铅离子吸附的最佳条件,铅离子的去除率高达89%。

关键词: 香蕉假茎         等温线     吸附     响应面分析法    

Automated retrofit targeting of heat exchanger networks

Walmsley, Nathan S. Lal, Petar S. Varbanov, Jiří J. Klemeš

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 630-642 doi: 10.1007/s11705-018-1747-2

摘要:

The aim of this paper is to develop a novel heat exchanger network (HEN) retrofit method based on a new automated retrofit targeting (ART) algorithm. ART uses the heat surplus-deficit table (HSDT) in combination with the Bridge Retrofit concepts to generate retrofit bridges option, from which a retrofit design may be formulated. The HSDT is a tabular tool that shows potential for improved re-integration of heat source and sink streams within a HEN. Using the HSDT, retrofit bridges—a set of modifications that links a cooler to a heater to save energy—may be identified, quantified, and compared. The novel retrofit method including the ART algorithm has been successfully implemented in Microsoft ExcelTM to enable analysis of large-scale HENs. A refinery case study with 27 streams and 46 existing heat exchangers demonstrated the retrofit method’s potential. For the case study, the ART algorithm found 68903 feasible unique retrofit opportunities with a minimum 400 kW·unit−1 threshold for heat recovery divided by the number of new units. The most promising retrofit project required 3 new heat exchanger units to achieve a heat savings of 4.24 MW with a favorable annualised profit and a reasonable payback period.

关键词: process retrofit     pinch analysis     heat exchanger network     heat recovery    

Techno-economic evaluation of wind energy in southwest Nigeria

Muyiwa S. ADARAMOLA, Olarenwaju M. OYEWOLA, Olayinka S. OHUNAKIN, Rufus R. DINRIFO

《能源前沿(英文)》 2012年 第6卷 第4期   页码 366-378 doi: 10.1007/s11708-012-0205-y

摘要: In this study, an analysis of the wind energy potential in the southwest geo-political region of Nigeria was conducted. A 37-year (1971–2007) wind speed data set measured at 10 m height, obtained from eight meteorological stations within the region was analyzed using a 2-parameter Weibull function. Besides, a techno-economic evaluation of large wind energy conversion systems with power ratings ranging from 0.6 to 2 MW at different hub heights based on the levelized unit cost of electricity was made for the different sites considered. The result showed that electricity cost varied from 0.06997 and 0.11195 $/(kW·h) to 2.86611 and 4.58578 $/(kW·h) at limit values of turbine specific cost band intervals of 1000 and 1600 $/kW. It was further shown that Lagos, having the highest accumulated power outputs of 430.10 kW/a from DeWind D7 at 70 m hub height, is the most preferred for economically usable power generation in terms of the levelized unit cost.

关键词: mean wind speed     Weibull distributions     wind turbine     techno-economic analysis     southwest geopolitical region     Nigeria    

Estimation of power in low velocity vertical axis wind turbine

Sampath S. S.,Sawan SHETTY,Chithirai Pon Selvan M.

《机械工程前沿(英文)》 2015年 第10卷 第2期   页码 211-218 doi: 10.1007/s11465-015-0338-x

摘要:

The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

关键词: wind turbine     shaft design     power generation     generator    

Biofuels and food security

Dmitry S. STREBKOV

《农业科学与工程前沿(英文)》 2015年 第2卷 第1期   页码 1-12 doi: 10.15302/J-FASE-2015052

摘要: The major source of energy comes from fossil fuels. The current situation in the field of fuel and energy is becoming more problematic as world population continues to grow because of the limitation of fossil fuels reserve and its pressure on environment. This review aims to find economic, reliable, renewable and non-polluting energy sources to reduce high energy tariffs in Russian Federation. Biofuel is fuel derived directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes. Other alternative energy sources including solar energy and electric power generation are also discussed. Over 100 Mt of biomass available for energy purposes is produced every year in Russian. One of the downsides of biomass energy is its potential threatens to food security and forage industries. An innovative approach proved that multicomponent fuel (80% diesel oil content for motor and 64% for in stove fuel) can remarkably reduce the costs. This paper proposed that the most promising energy model for future is based on direct solar energy conversion and transcontinental terawatt power transmission with the use of resonant wave-guide technology.

关键词: fossil fuels     biofuels     food security     electric power     solar energy    

Orderly decorated nanostructural photoelectrodes with uniform spherical TiO

Bakhshayesh,S. S. Azadfar

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 532-540 doi: 10.1007/s11705-015-1549-8

摘要: This study presents a novel nanostructural electrode made of 20-nm-diameter nanoparticles, which orderly decorated with 2-µm TiO particles, deposited by a new gel process. The decorated electrode (DE) is better than the non-decorated electrode (NE) in both light scattering and light harvesting, as confirmed by diffuse reflectance spectroscopy. X-ray diffraction reveals that both electrodes have a mixture of anatase and rutile phases. The dye-sensitized solar cell based on the decorated electrode shows the highest power conversion efficiency of 7.80% as a result of less recombination demonstrated by electrochemical impedance spectroscopy. From internal power conversion efficiency measurement, the external quantum efficiency of DE cell at 530 nm is 89%, which is higher than that of NE cell (77%).

关键词: dye-sensitized solar cell     uniform particles     TiO2 gel process     light harvesting    

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要: The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词: piezoelectricity     impedance curve     mode shapes     inverse problem     flaw detection     curve shifting    

Microplastics pollution and reduction strategies

Wei-Min Wu,Jun Yang,Craig S. Criddle

《环境科学与工程前沿(英文)》 2017年 第11卷 第1期 doi: 10.1007/s11783-017-0897-7

摘要: Microplastic particles smaller than 5 mm in size are of increasing concern, especially in aquatic environments, such as the ocean. Primary source is microbeads (<1 mm) used in cosmetics and cleaning agents and fiber fragments from washing of clothes, and secondary source such as broken down plastic litter and debris. These particles are mostly made from polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyesters. They are ingested by diverse marine fauna, including zooplanktons, mussel, oyster, shrimp, fish etc. and can enter human food chains via several pathways. Strategy for control of microplastics pollution should primarily focus on source reduction and subsequently on the development of cost-effective clean up and remediation technologies. Recent research results on biodegradation of plastics have revealed a potential for microbial biodegradation and bioremediation of plastic pollutants, such as PE, PS and PET under appropriate conditions.

关键词: microplastics     plastic microbeads     environmental pollution     biodegradation    

Soil health—useful terminology for communication or meaningless concept? Or both?

David S. POWLSON

《农业科学与工程前沿(英文)》 2020年 第7卷 第3期   页码 246-250 doi: 10.15302/J-FASE-2020326

Effect of lime on speciation of heavy metals during composting of water hyacinth

Jiwan SINGH,Ajay S. KALAMDHAD

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 93-102 doi: 10.1007/s11783-014-0704-7

摘要: Composting is attractive and inexpensive method for treatment and biomass disposal of water hyacinth. However, the major disadvantage of water hyacinth composting is the high content of heavy metals in the final compost. Addition of lime sludge significantly reduced most bioavailable fractions (exchangeable and carbonate) of heavy metals. Studies were carried on composting of water hyacinth ( ) with cattle manure and sawdust (6:3:1 ratio) and effects of addition of lime (1%, 2% and 3%) on heavy metal speciation were evaluated during 30 days of composting period. The Tessier sequential extraction method was employed to investigate the changes in speciation of heavy metals such as Zinc (Zn), Copper (Cu), Manganese (Mn), Iron (Fe), Lead (Pb), Nickel (Ni), Cadmium (Cd) and Chromium (Cr) during water hyacinth composting. Effects of physicochemical parameters such as temperature, pH and organic matter on speciation of heavy metals were also studied during the process. Results showed that, the total metal content was increased during the composting process. The higher reduction in bioavailability factor (BF) of Cu, Fe, Ni, Cd and Cr was observed in lime 2 treatment about 62.1%, 64.4%, 71.9%, 62.1% and 58.9% respectively; however higher reduction in BF of Zn and Pb was observed in lime 1 treatment during the composting process. Reducible and oxidizable fractions of Ni, Pb and Cd were not observed during the process. Addition of lime was very effective for reduction of bioavailability of heavy metals during composting of water hyacinth with cattle manure and sawdust.

关键词: composting     lime     heavy metals     bioavailability factor     speciation    

Influence of loading ratio on flat slab connections at elevated temperature: A numerical study

S. AL-HAMD, Martin GILLIE, Safaa Adnan MOHAMAD, Lee S. CUNNINGHAM

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 664-674 doi: 10.1007/s11709-020-0620-9

摘要: For reinforced concrete members subjected to high temperature, the degree of in-service loading, commonly expressed as the loading ratio, can be highly influential on the structural behavior. In particular, the loading ratio may be pivotal in relation to the phenomenon of load-induced thermal strain. Despite its potentially pivotal role, to date, the influence of the loading ratio on both material and structural behavior has not been explored in detail. In practice, real structures experience variation in imposed loading during their service life and it is important to understand the likely response at elevated temperatures across the loading envelope. In this paper, the effect of the loading ratio is numerically investigated at both material and structural level using a validated finite element model. The model incorporates a proposed constitutive model accounting for load-induced thermal strain and this is shown to outperform the existing Eurocode 2 model in terms of accuracy. Using the validated model, the specific case of flats slabs and the associated connections to supporting columns at various loading ratios are explored. For the cases examined, a marked difference in the structural behavior including displacement direction was captured from low to high loading ratios consistent with experimental observations.

关键词: concrete     finite elements     fire     load-induced thermal strain     punching shear    

Cancer and the environment: Filling knowledge gaps together

Linda S. BIRNBAUM PhD, DABT, ATS,

《医学前沿(英文)》 2010年 第4卷 第2期   页码 131-133 doi: 10.1007/s11684-010-0044-3

摘要: When considering disease etiology, we need to view the role of the environment along the continuum from health to disease for individuals because we know that there are complex interactions between genes, their molecular expression, and environmental factors over a person’s lifetime. We clearly have huge gaps in our knowledge along this continuum, and these gaps are natural opportunities for research. There are many factors to consider as we assess the relationship between environmental exposures over a lifetime. One factor is persistence of chemicals that “live” beyond their initial intended use. Another factor is the fact that “inert ingredients” are not really inert. “Low dose” is also another consideration. We need to understand the biological effect of low dose exposure and we should clearly define what they mean by low dose research. For example, are we measuring the administered dose, or the internal/circulating dose? There are new types of toxicity as well. For example, endocrine disruptors and engineered nanomaterials are significant classes of materials deserving significant research. Timing of exposure is a significant feature in characterizing toxicity. Environmental exposures can have a greater impact in early or later life-stages. Finally, mixtures of chemicals are an important consideration. Humans are always exposed to multiple chemicals. In short, we must remember that there is no such thing as “not exposed.” Everyone has been exposed to many and various environmental agents.

关键词: environment     genes     environmental exposure     environmental agent     persistence     chemicals     inert ingredients     low dose    

Plated contacts for solar cells with superior adhesion strength to screen printed solar cells

CHEN,S. WANG,A. WENHAM,Z. SHI,T. YOUNG,J. JI,M. EDWARDS,A. SUGIANTO,L. MAI,S. WENHAM,C. CHONG

《能源前沿(英文)》 2017年 第11卷 第1期   页码 72-77 doi: 10.1007/s11708-016-0428-4

摘要: The improvement of adhesion strength and durability of plated contacts is required for cell manufacturers to gain confidence for large-scale manufacturing. To overcome weak adhesion at the metal/Si interface, new approaches were developed. These involve the formation of laser-ablated anchor points, or grooves in the extreme case of overlapping anchor points, in the heavily doped silicon surface. When plated, these features greatly strengthen the mechanical adhesion strength of the metal. A stylus-based adhesion tester was developed specifically for evaluating the effectiveness of plated contacts to smooth silicon surfaces. The use of such a tester was also extended in this work to textured and roughened surfaces to allow evaluation of different metal contacting approaches. The adhesion strengths for various metal contacting schemes were evaluated, including screen-printed silver contacts, nickel/copper (Ni/Cu) light-induced plated (LIP) contacts for laser-doped selective emitter (LDSE) cells, buried-contact solar cells (BCSCs), and Ni/Cu LIP contacts formed with laser-ablated anchoring points in selective emitter (LAASE) cells. The latter has superior adhesion strength. The standard “peel test” of the industry was compared to the stylus-based adhesion testing, with the latter shown value for testing metal contacts on smooth surfaces but with caution needed for use with textured or roughened surfaces.

关键词: light-induced plating     metal adhesion strength     copper plating     metal contacts     solar cell durability     silicon solar cells    

标题 作者 时间 类型 操作

Antibiotic resistome of : molecular determinants for the emergence of drug resistance

期刊论文

Exergy analysis and simulation of a 30MW cogeneration cycle

Nikhil Dev, Samsher, S. S. Kachhwaha, Rajesh Attri

期刊论文

香蕉假茎作为吸附剂用于水溶液中铅离子去除的条件优化、动力学与吸附平衡研究

Shridhar S. Bagali, Bychapur S. Gowrishankar, Aashis S. Roy

期刊论文

Automated retrofit targeting of heat exchanger networks

Walmsley, Nathan S. Lal, Petar S. Varbanov, Jiří J. Klemeš

期刊论文

Techno-economic evaluation of wind energy in southwest Nigeria

Muyiwa S. ADARAMOLA, Olarenwaju M. OYEWOLA, Olayinka S. OHUNAKIN, Rufus R. DINRIFO

期刊论文

Estimation of power in low velocity vertical axis wind turbine

Sampath S. S.,Sawan SHETTY,Chithirai Pon Selvan M.

期刊论文

Biofuels and food security

Dmitry S. STREBKOV

期刊论文

Orderly decorated nanostructural photoelectrodes with uniform spherical TiO

Bakhshayesh,S. S. Azadfar

期刊论文

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

期刊论文

Microplastics pollution and reduction strategies

Wei-Min Wu,Jun Yang,Craig S. Criddle

期刊论文

Soil health—useful terminology for communication or meaningless concept? Or both?

David S. POWLSON

期刊论文

Effect of lime on speciation of heavy metals during composting of water hyacinth

Jiwan SINGH,Ajay S. KALAMDHAD

期刊论文

Influence of loading ratio on flat slab connections at elevated temperature: A numerical study

S. AL-HAMD, Martin GILLIE, Safaa Adnan MOHAMAD, Lee S. CUNNINGHAM

期刊论文

Cancer and the environment: Filling knowledge gaps together

Linda S. BIRNBAUM PhD, DABT, ATS,

期刊论文

Plated contacts for solar cells with superior adhesion strength to screen printed solar cells

CHEN,S. WANG,A. WENHAM,Z. SHI,T. YOUNG,J. JI,M. EDWARDS,A. SUGIANTO,L. MAI,S. WENHAM,C. CHONG

期刊论文