Electric vehicles (EVs) are the most interesting and innovative technology in the 21st century because of theirenormous advantages, both technically and economically. Their emissions rate compared to fuel-based vehicl...Electric vehicles (EVs) are the most interesting and innovative technology in the 21st century because of theirenormous advantages, both technically and economically. Their emissions rate compared to fuel-based vehicles isnegligible as they do not consume fuel and hence do not emit any harmful gases. However, their bulk production,adoption and lack of charging stations increase the stress of power stations due to modern-day lifestyles. If Electricvehicles demand increases drastically then conventional power stations will not bear their demand and if theygenerate electricity by conventional means it will be very costly and may further add greenhouse gases. Therefore,this research provides the techno-economic assessment of a stand-alone renewable-dependent electric vehiclecharging station, excluding any burden on electrical utility. The proposed study is carried out in Bahria Town,Karachi, a city in Pakistan. In this study, HOMER Pro software was utilized for techno-economic assessment. Ahybrid system comprising solar Photovoltaic/Wind Turbine/Fuel cells and battery storage is included in the model.Solar and wind resources were taken from NASA’s website, where charging stations will be integrated. The overallresults show promising in terms of total Net Present Cost and the Cost of Energy which are 2.72M $ and 0.237 $,respectively. The total system generation is 3,598 Megawatt hours per year, and the total energy consumption is 885Megawatt hours per year.展开更多
In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential inve...In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.展开更多
With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic a...With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic ation system transforms from file-based structure to C/S and then CSS model. At the same time, following the prevalence of Internet/Intranet, Web application s ystem based on browser comes into being. In early time, Web application only pro vided functions of looking over or querying static data on browser. But with the development of Internet/Intranet widely, it’s expected that more and more trad itional applications can be performed on browser, or even E-Business trades and other complicated application systems such as MIS, ERP and CRM and so on. In or der to satisfy both traditional application and Web application, reduce the cost of developing system repeatedly, increase the repeated use of application syste m and take advantage of the functions of OOA/OOD sufficiently, a new distributed architecture structure (system solution based on repeated components) comes for th. In this article, this distributed architecture structure will be discuss ed in detail. Firstly, the evolution of traditional application system and Web application sys tem will be talked over, especially the advantages and disadvantages of these tw o architectures. Secondly, the distributed architecture (system solution based o n repeated components) will be described particular. Several prevalent technolog y of component, such as COM+, CORBA and EJB, will also be illustrate d in this part. Thirdly, the practice of the technology of repeated component wi ll be discussed by analysing and designing the management system of Science & Te chnology Articles. Lastly, the latest distributed techonlogy of E-business(Web service based on xml/soap) will be discussed. In the end, Based on summing-up o f the distributed technology of E-Business, the future distributed tenchnology of E-Business will be expected.展开更多
There is an increasing concern that current trends of consumption of natural resources cannot continue.It is imperative that major targeted investments are made into economical and reliable environment friendly propul...There is an increasing concern that current trends of consumption of natural resources cannot continue.It is imperative that major targeted investments are made into economical and reliable environment friendly propulsion and power solutions.Many novel and promising concepts are being proposed.The selection of the best candidates to pursue for investment becomes a very difficult choice.A detailed TERA(techno-economic environmental risk analysis) framework is described here to quantify risks and to compare and rank competing schemes on a formal and consistent basis.This technique is based on detailed and rigorous thermodynamic representations of power plants.A layer of environment,economic,weather and other models to describe the appropriate local conditions is superimposed to this.The outcome is a techno-economic environmental risk analysis framework with appropriate detail of each power plant as applied to the appropriate conditions.The results for each concept can then be compared and contrasted to make appropriate selections.展开更多
With the explosion of information technology, many foreign language teachers are concerned that technology will impose distance in the student-teacher relationship and both teaching and learning will suffer. To make f...With the explosion of information technology, many foreign language teachers are concerned that technology will impose distance in the student-teacher relationship and both teaching and learning will suffer. To make full use of information technology without loss of social interaction in classroom, techno-constructivism is recommended. Examples of effective implementation of techno-constructivist pedagogy in EFL teaching are given to demonstrate how to ensure effective learning.展开更多
This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system...This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system in science and technology in China. The countermeasures are proposed with a hope to shorten China's and US's gap of agricultural innovation in science and technology by analyzing agricultural innovation model features in science and technology of the United States. The advantages of United States model of agricultural innovation in science and technology include sound legal framework safeguard, complete scientific and technological innovation system, high quality and talented personnel, sufficient technical development and extension funding, and extensive applications of modern agricultural high-tech. There is a gap in agricultural innovation between China and the United States. Agriculture innovation in science and technology in China should improve in several aspects such as agricultural legislation, construction of sound agricultural innovation system in science and technology, building first-class agricultural innovation and extension teams, establishing diversified channels for investment, and improving the applications of high technology in agriculture.展开更多
On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and an...On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.展开更多
Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed ...Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed algorithm combines the make-to-order (MTO) and charge optimization planning (COP) of the steel melting shop in the production of target steel composition. Using a system-level approach, the unit operations involved in the melting process were analyzed with the purpose of initial charge calculation, prevailing alloy charge prediction and optimizing the sequence of melt chemistry modification. The model performance was established using real-time production data from a cast iron-based foundry with a 1- and 2-ton induction furnace capacity and a medium carbon-based foundry with a 10- and 15-ton induction furnace capacity. A simulation engine (CastMELT) was developed in Java IDE with a MySQL database for continuous interaction with changing process parameters to run the model for validation. The comparison between the model prediction and production results was analyzed for charge prediction, melt modification and ferroalloy optimization and possible cost savings. The model performance for elemental charge prediction and calculation purpose with respect to the charge input (at overall scrap meltdown) gave R-squared, Standard Error, Pearson correlation and Significance value of (0.934, 0.06, 0.97, 0.0003) for Carbon prediction, (0.962, 0.06, 0.98, 0.00009) for Silicon prediction, (0.999, 0.048, 0.999, 9E -11) for Manganese Prediction, and (0.997, 0.076, 0.999, 6E -7) for Chromium prediction respectively. Correlation analysis for melt modification (after charging of ferroalloy) using the model for after-alloying spark analysis compared with the target chemistry is at 99.82%. The results validate the suitability of the developed model as a functional system of induction furnace melting for combined charge calculation and melt optimization Techno-economic evaluation results showed that 0.98% - 0.25% ferroalloy saving per ton of melt is possible using the model. This brings about an annual production cost savings of 100,000 $/y in foundry A (medium carbon steel) and 20,000 $/y in foundry B (cast iron) on the use of different ferroalloy materials.展开更多
With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of e...With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of energy. Under the circums-tances it is highly desirable that renewable energy resources should be utilized with maximum conversion efficiency to cope with the ever increasing energy demand. Furthermore, the global economic and political conditions that tend to make countries more dependent on their own energy resources have caused growing interest in the development and use of renewable energy based technologies. In terms of its environmental advantages, renewable energy sources generate electricity with insignificant contribution of carbon dioxide (CO2) or other greenhouse gases (GHG) to the atmosphere and they produce no pollutant discharge on water or soil and hence power generation from renewable becomes very important. Major types of renewable energy sources include solar, wind, hydro and biomass, all of which have huge potential to meet future energy challenges. Solar photovoltaic technology in one of the first among several renewable energy technologies that have been adopted worldwide for meeting the basic needs of electricity particularly in remote areas. In this paper literature review pertaining to techno-economic feasibility analysis of solar photovoltaic power generation is discussed. The literature is basically classified into the following three main category design methods, techno-economic feasibility of solar photovoltaic power generation, performance evaluations of various systems.展开更多
Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for elec...Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.展开更多
This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by m...This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by means of series engineering design. The results show that land treatment can save 50-70% of capital costs, 80-90% of power and 75-85% of operation costs when compared with secondary treatment.展开更多
A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of bi...A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre(CHF) membrane and compare with a commercially available polymeric membrane(polyimide) through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO_2, O_2, N_2. The CHF membrane was modified through oxidation, chemical vapour deposition(CVD) and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres(PORCHFs) significantly exceeded CHF performance showing higher CO_2 permeance(0.021 m^3(STP)/m^2 h bar) and CO_2/CH_4 selectivity of 246(5 bar feed vs 50 mbar permeate pressure). The highest performance recorded through experiments(CHF and PORCHF) was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS.A 300 Nm^3/h mixture of CO_2/CH_4 containing 30-50% CO_2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover99.5% CH_4 with 97.5% purity. Net present value(NPV) was calculated for base case and optimal pressure(50 bar for CHF and PORCHF). The results indicated that recycle ratio(recycle/feed) ranged from 0.2 to 10, specific energy from 0.15 to 0.8(kW/Nm^3 feed) and specific membrane area from 45 to 4700(m^2/Nm^3 feed). The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm^3 and a lifetime of 15 years, the technoeconomic analysis showed that payback time for the best cascade is 1.6 months.展开更多
Like most roots and tubers, taro (Colocasia esculenta) corms have a short shelf-life due to the high moisture content, which aggravates their post-harvest losses. They also contain high amounts of calcium oxalates, li...Like most roots and tubers, taro (Colocasia esculenta) corms have a short shelf-life due to the high moisture content, which aggravates their post-harvest losses. They also contain high amounts of calcium oxalates, limiting their use in food applications. To help add value and diversify the use of taro corms as well as curb food losses, various strategies have been proposed, such processing of the corms into flour. This study aimed at evaluating the total oxalate content and techno-functional properties of taro flour as affected by the pre-gelatinization conditions (i.e., method and time). Pre-gelatinized taro flour was prepared by subjecting peeled and cleaned taro corms to roasting (190°C), boiling (100°C), and steaming (100°C) for 10 min, 20 min and 30 min, respectively, for each method, followed by drying at 55°C and milling. Generally, all the properties of flour were significantly affected by the pre-gelatinization conditions (P 0.05). The total oxalate content of the pre-gelatinized taro flour ranged from 33.26 to 76.90 mg/100g. Pre-gelatinization by boiling significantly reduced the oxalate content (56.7%), while roasting resulted in the least reduction (36.2%). The flour colour i.e. L<sup>*</sup>, hue, and chroma ranged from 38.47° - 70.30°, 42.64° - 69.43°, and 7.78° - 10.58°, respectively. Roasting resulted in flour with the largest L<sup>*</sup> (70.30°) and hue angle (69.43°). Boiling also resulted in flour with the highest bulk density (BD) (0.86 g/cm<sup>3</sup>) and the lowest water solubility index (WSI) (9.39%). Steamed flour had the highest water absorption index (WAI) (3.81 g/g), water holding capacity (WHC) (4.59 g/g), and swelling capacity (SC) (4.86 g/g). This study shows that pre-gelatinization (i.e. by boiling, steaming or roasting) significantly affects the total oxalate content and techno-functional properties of taro flour, which in turn influences its use in other food applications thus increasing the utilization and production of taro simultaneously.展开更多
Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating ...Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.展开更多
India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style=&...India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"> is consumed in various domestic and commercial activities within the state. The rest of the material is burned causing severe contamination of air with smoke. There is an urgent need to identify suitable and sustainable conversion technologies that are efficient, eco-friendly as well as cost-effective for managing the huge available biomass not only in the state but also in the country. This paper reviews briefly the available crop residue and quantities burned, proposes a scheme to incorporate part of the residue in the field for its fertilizer value. The remaining biomass is harvested for animal feed and the excess is converted to bioenergy and biofuels. Among the developed and developing biofuels, the paper identifies biogas production from biomass for on-farm use. Pelletization is identified as an enabling technology to provide high quality feedstock for conversion to heat/power and in near future to advanced biofuels.展开更多
In the reading process and after reading of the scientific and technological English literature for postgraduates of engineering, there are several barriers like the understanding of the vocabulary, the analyzing the ...In the reading process and after reading of the scientific and technological English literature for postgraduates of engineering, there are several barriers like the understanding of the vocabulary, the analyzing the complex sentences and the grasping the whole texts. This paper tries to investigate the using condition of interactive reading strategy in reading scientific and technological English literature of postgraduates of engineering. The study reveals that postgraduates of engineering frequently using some of strategies of the interactive reading strategy, but the overall using condition is only in the average level, and is not so flexible.展开更多
11% of Irish electricity was consumed by data centres in 2020. The Irish data centre industry and the cooling methods utilised require reformative actions in the coming years to meet EU Energy policies. The resell of ...11% of Irish electricity was consumed by data centres in 2020. The Irish data centre industry and the cooling methods utilised require reformative actions in the coming years to meet EU Energy policies. The resell of heat, alternative cooling methods or carbon reduction methods are all possibilities to conform to these policies. This study aims to determine the viability of the resell of waste heat from data centres both technically and economically. This was determined using a novel application of thermodynamics to determine waste heat recovery potential in Irish data centres, and the current methods of heat generation for economical comparison. This paper also explores policy surrounding waste heat recovery within the industry. The Recoverable Carnot Equivalent Power (RCEP) is theoretically calculated for the three potential cooling methods for Irish data centres. These are air, hybrid, and immersion cooling techniques. This is the maximum useable heat that can be recovered from a data centre rack. This study is established under current operating conditions which are optimised for cooling performance, that air cooling has the highest potential RCEP of 0.39 kW/rack. This is approximately 8% of the input electrical power that can be captured as useable heat. Indicating that Irish data centres have the energy potential to be heat providers in the Irish economy. This study highlighted the technical and economic aspects of prevalent cooling techniques and determined air cooling heat recovery cost can be reduced to 0.01 €/kWhth using offsetting. This is financially competitive with current heating solutions in Ireland.展开更多
文摘Electric vehicles (EVs) are the most interesting and innovative technology in the 21st century because of theirenormous advantages, both technically and economically. Their emissions rate compared to fuel-based vehicles isnegligible as they do not consume fuel and hence do not emit any harmful gases. However, their bulk production,adoption and lack of charging stations increase the stress of power stations due to modern-day lifestyles. If Electricvehicles demand increases drastically then conventional power stations will not bear their demand and if theygenerate electricity by conventional means it will be very costly and may further add greenhouse gases. Therefore,this research provides the techno-economic assessment of a stand-alone renewable-dependent electric vehiclecharging station, excluding any burden on electrical utility. The proposed study is carried out in Bahria Town,Karachi, a city in Pakistan. In this study, HOMER Pro software was utilized for techno-economic assessment. Ahybrid system comprising solar Photovoltaic/Wind Turbine/Fuel cells and battery storage is included in the model.Solar and wind resources were taken from NASA’s website, where charging stations will be integrated. The overallresults show promising in terms of total Net Present Cost and the Cost of Energy which are 2.72M $ and 0.237 $,respectively. The total system generation is 3,598 Megawatt hours per year, and the total energy consumption is 885Megawatt hours per year.
文摘In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.
文摘With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic ation system transforms from file-based structure to C/S and then CSS model. At the same time, following the prevalence of Internet/Intranet, Web application s ystem based on browser comes into being. In early time, Web application only pro vided functions of looking over or querying static data on browser. But with the development of Internet/Intranet widely, it’s expected that more and more trad itional applications can be performed on browser, or even E-Business trades and other complicated application systems such as MIS, ERP and CRM and so on. In or der to satisfy both traditional application and Web application, reduce the cost of developing system repeatedly, increase the repeated use of application syste m and take advantage of the functions of OOA/OOD sufficiently, a new distributed architecture structure (system solution based on repeated components) comes for th. In this article, this distributed architecture structure will be discuss ed in detail. Firstly, the evolution of traditional application system and Web application sys tem will be talked over, especially the advantages and disadvantages of these tw o architectures. Secondly, the distributed architecture (system solution based o n repeated components) will be described particular. Several prevalent technolog y of component, such as COM+, CORBA and EJB, will also be illustrate d in this part. Thirdly, the practice of the technology of repeated component wi ll be discussed by analysing and designing the management system of Science & Te chnology Articles. Lastly, the latest distributed techonlogy of E-business(Web service based on xml/soap) will be discussed. In the end, Based on summing-up o f the distributed technology of E-Business, the future distributed tenchnology of E-Business will be expected.
文摘There is an increasing concern that current trends of consumption of natural resources cannot continue.It is imperative that major targeted investments are made into economical and reliable environment friendly propulsion and power solutions.Many novel and promising concepts are being proposed.The selection of the best candidates to pursue for investment becomes a very difficult choice.A detailed TERA(techno-economic environmental risk analysis) framework is described here to quantify risks and to compare and rank competing schemes on a formal and consistent basis.This technique is based on detailed and rigorous thermodynamic representations of power plants.A layer of environment,economic,weather and other models to describe the appropriate local conditions is superimposed to this.The outcome is a techno-economic environmental risk analysis framework with appropriate detail of each power plant as applied to the appropriate conditions.The results for each concept can then be compared and contrasted to make appropriate selections.
文摘With the explosion of information technology, many foreign language teachers are concerned that technology will impose distance in the student-teacher relationship and both teaching and learning will suffer. To make full use of information technology without loss of social interaction in classroom, techno-constructivism is recommended. Examples of effective implementation of techno-constructivist pedagogy in EFL teaching are given to demonstrate how to ensure effective learning.
基金Supported by Jiangsu Overseas Research&Training Program for University Prominent Young&Middle-aged Teachers and Presidents(2011)Jiangsu Province"333"High-level Talents Program(2011)University Philosophical and Social Science Research Program of the Education Department in Jiangsu Province in 2010(2010SJD630050)
文摘This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system in science and technology in China. The countermeasures are proposed with a hope to shorten China's and US's gap of agricultural innovation in science and technology by analyzing agricultural innovation model features in science and technology of the United States. The advantages of United States model of agricultural innovation in science and technology include sound legal framework safeguard, complete scientific and technological innovation system, high quality and talented personnel, sufficient technical development and extension funding, and extensive applications of modern agricultural high-tech. There is a gap in agricultural innovation between China and the United States. Agriculture innovation in science and technology in China should improve in several aspects such as agricultural legislation, construction of sound agricultural innovation system in science and technology, building first-class agricultural innovation and extension teams, establishing diversified channels for investment, and improving the applications of high technology in agriculture.
文摘On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.
文摘Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed algorithm combines the make-to-order (MTO) and charge optimization planning (COP) of the steel melting shop in the production of target steel composition. Using a system-level approach, the unit operations involved in the melting process were analyzed with the purpose of initial charge calculation, prevailing alloy charge prediction and optimizing the sequence of melt chemistry modification. The model performance was established using real-time production data from a cast iron-based foundry with a 1- and 2-ton induction furnace capacity and a medium carbon-based foundry with a 10- and 15-ton induction furnace capacity. A simulation engine (CastMELT) was developed in Java IDE with a MySQL database for continuous interaction with changing process parameters to run the model for validation. The comparison between the model prediction and production results was analyzed for charge prediction, melt modification and ferroalloy optimization and possible cost savings. The model performance for elemental charge prediction and calculation purpose with respect to the charge input (at overall scrap meltdown) gave R-squared, Standard Error, Pearson correlation and Significance value of (0.934, 0.06, 0.97, 0.0003) for Carbon prediction, (0.962, 0.06, 0.98, 0.00009) for Silicon prediction, (0.999, 0.048, 0.999, 9E -11) for Manganese Prediction, and (0.997, 0.076, 0.999, 6E -7) for Chromium prediction respectively. Correlation analysis for melt modification (after charging of ferroalloy) using the model for after-alloying spark analysis compared with the target chemistry is at 99.82%. The results validate the suitability of the developed model as a functional system of induction furnace melting for combined charge calculation and melt optimization Techno-economic evaluation results showed that 0.98% - 0.25% ferroalloy saving per ton of melt is possible using the model. This brings about an annual production cost savings of 100,000 $/y in foundry A (medium carbon steel) and 20,000 $/y in foundry B (cast iron) on the use of different ferroalloy materials.
文摘With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of energy. Under the circums-tances it is highly desirable that renewable energy resources should be utilized with maximum conversion efficiency to cope with the ever increasing energy demand. Furthermore, the global economic and political conditions that tend to make countries more dependent on their own energy resources have caused growing interest in the development and use of renewable energy based technologies. In terms of its environmental advantages, renewable energy sources generate electricity with insignificant contribution of carbon dioxide (CO2) or other greenhouse gases (GHG) to the atmosphere and they produce no pollutant discharge on water or soil and hence power generation from renewable becomes very important. Major types of renewable energy sources include solar, wind, hydro and biomass, all of which have huge potential to meet future energy challenges. Solar photovoltaic technology in one of the first among several renewable energy technologies that have been adopted worldwide for meeting the basic needs of electricity particularly in remote areas. In this paper literature review pertaining to techno-economic feasibility analysis of solar photovoltaic power generation is discussed. The literature is basically classified into the following three main category design methods, techno-economic feasibility of solar photovoltaic power generation, performance evaluations of various systems.
文摘Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.
文摘This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by means of series engineering design. The results show that land treatment can save 50-70% of capital costs, 80-90% of power and 75-85% of operation costs when compared with secondary treatment.
文摘A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre(CHF) membrane and compare with a commercially available polymeric membrane(polyimide) through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO_2, O_2, N_2. The CHF membrane was modified through oxidation, chemical vapour deposition(CVD) and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres(PORCHFs) significantly exceeded CHF performance showing higher CO_2 permeance(0.021 m^3(STP)/m^2 h bar) and CO_2/CH_4 selectivity of 246(5 bar feed vs 50 mbar permeate pressure). The highest performance recorded through experiments(CHF and PORCHF) was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS.A 300 Nm^3/h mixture of CO_2/CH_4 containing 30-50% CO_2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover99.5% CH_4 with 97.5% purity. Net present value(NPV) was calculated for base case and optimal pressure(50 bar for CHF and PORCHF). The results indicated that recycle ratio(recycle/feed) ranged from 0.2 to 10, specific energy from 0.15 to 0.8(kW/Nm^3 feed) and specific membrane area from 45 to 4700(m^2/Nm^3 feed). The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm^3 and a lifetime of 15 years, the technoeconomic analysis showed that payback time for the best cascade is 1.6 months.
文摘Like most roots and tubers, taro (Colocasia esculenta) corms have a short shelf-life due to the high moisture content, which aggravates their post-harvest losses. They also contain high amounts of calcium oxalates, limiting their use in food applications. To help add value and diversify the use of taro corms as well as curb food losses, various strategies have been proposed, such processing of the corms into flour. This study aimed at evaluating the total oxalate content and techno-functional properties of taro flour as affected by the pre-gelatinization conditions (i.e., method and time). Pre-gelatinized taro flour was prepared by subjecting peeled and cleaned taro corms to roasting (190°C), boiling (100°C), and steaming (100°C) for 10 min, 20 min and 30 min, respectively, for each method, followed by drying at 55°C and milling. Generally, all the properties of flour were significantly affected by the pre-gelatinization conditions (P 0.05). The total oxalate content of the pre-gelatinized taro flour ranged from 33.26 to 76.90 mg/100g. Pre-gelatinization by boiling significantly reduced the oxalate content (56.7%), while roasting resulted in the least reduction (36.2%). The flour colour i.e. L<sup>*</sup>, hue, and chroma ranged from 38.47° - 70.30°, 42.64° - 69.43°, and 7.78° - 10.58°, respectively. Roasting resulted in flour with the largest L<sup>*</sup> (70.30°) and hue angle (69.43°). Boiling also resulted in flour with the highest bulk density (BD) (0.86 g/cm<sup>3</sup>) and the lowest water solubility index (WSI) (9.39%). Steamed flour had the highest water absorption index (WAI) (3.81 g/g), water holding capacity (WHC) (4.59 g/g), and swelling capacity (SC) (4.86 g/g). This study shows that pre-gelatinization (i.e. by boiling, steaming or roasting) significantly affects the total oxalate content and techno-functional properties of taro flour, which in turn influences its use in other food applications thus increasing the utilization and production of taro simultaneously.
文摘Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.
文摘India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"> is consumed in various domestic and commercial activities within the state. The rest of the material is burned causing severe contamination of air with smoke. There is an urgent need to identify suitable and sustainable conversion technologies that are efficient, eco-friendly as well as cost-effective for managing the huge available biomass not only in the state but also in the country. This paper reviews briefly the available crop residue and quantities burned, proposes a scheme to incorporate part of the residue in the field for its fertilizer value. The remaining biomass is harvested for animal feed and the excess is converted to bioenergy and biofuels. Among the developed and developing biofuels, the paper identifies biogas production from biomass for on-farm use. Pelletization is identified as an enabling technology to provide high quality feedstock for conversion to heat/power and in near future to advanced biofuels.
文摘In the reading process and after reading of the scientific and technological English literature for postgraduates of engineering, there are several barriers like the understanding of the vocabulary, the analyzing the complex sentences and the grasping the whole texts. This paper tries to investigate the using condition of interactive reading strategy in reading scientific and technological English literature of postgraduates of engineering. The study reveals that postgraduates of engineering frequently using some of strategies of the interactive reading strategy, but the overall using condition is only in the average level, and is not so flexible.
文摘11% of Irish electricity was consumed by data centres in 2020. The Irish data centre industry and the cooling methods utilised require reformative actions in the coming years to meet EU Energy policies. The resell of heat, alternative cooling methods or carbon reduction methods are all possibilities to conform to these policies. This study aims to determine the viability of the resell of waste heat from data centres both technically and economically. This was determined using a novel application of thermodynamics to determine waste heat recovery potential in Irish data centres, and the current methods of heat generation for economical comparison. This paper also explores policy surrounding waste heat recovery within the industry. The Recoverable Carnot Equivalent Power (RCEP) is theoretically calculated for the three potential cooling methods for Irish data centres. These are air, hybrid, and immersion cooling techniques. This is the maximum useable heat that can be recovered from a data centre rack. This study is established under current operating conditions which are optimised for cooling performance, that air cooling has the highest potential RCEP of 0.39 kW/rack. This is approximately 8% of the input electrical power that can be captured as useable heat. Indicating that Irish data centres have the energy potential to be heat providers in the Irish economy. This study highlighted the technical and economic aspects of prevalent cooling techniques and determined air cooling heat recovery cost can be reduced to 0.01 €/kWhth using offsetting. This is financially competitive with current heating solutions in Ireland.
