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Rotational Inertial Physics in Non-Classical Thermoviscous Fluent Continua Incorporating Internal Rotation Rates
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作者 K. S. Surana J. K. Kendall 《Applied Mathematics》 2022年第6期453-487,共35页
In this paper, we derive non-classical continuum theory for physics of compressible and incompressible thermoviscous non-classical fluent continua using the conservation and balance laws (CBL) by incorporating additio... In this paper, we derive non-classical continuum theory for physics of compressible and incompressible thermoviscous non-classical fluent continua using the conservation and balance laws (CBL) by incorporating additional physics of internal rotation rates arising from the velocity gradient tensor as well as their time varying rates and the rotational inertial effects. In this non-classical continuum theory time dependent deformation of fluent continua results in time varying rotation rates i.e., angular velocities and angular accelerations at material points. Resistance offered to these by deforming fluent continua results in additional moments, angular momenta and inertial effects due to rotation rates i.e., angular velocities and angular accelerations at the material points. Currently, this physics due to internal rotation rates and inertial effects is neither considered in classical continuum mechanics (CCM) nor in non-classical continuum mechanics (NCCM). In this paper, we present a derivation of conservation and balance laws in Eulerian description: conservation of mass (CM), balance of linear momenta (BLM), balance of angular momenta (BAM), balance of moment of moments (BMM), first and second laws of thermodynamics (FLT, SLT) that include: (i) Physics of internal rotation rates resulting from the velocity gradient tensor;(ii) New physics resulting due to angular velocities and angular accelerations due to spatially varying and time dependent rotation rates. The balance laws derived here are compared with those that only consider the rotational rates but neglect rotational inertial effects and angular accelerations to demonstrate the influence of the new physics. Constitutive variables and their argument tensors are established using conjugate pairs in the entropy inequality, additional desired physics and principle of equipresence when appropriate. Constitutive theories are derived using Helmholtz free energy density as well as representation theorem and integrity (complete basis). It is shown that the mathematical model consisting of the conservation and balance laws and constitutive theories presented in this paper has closure. Influence of new physics in the conservation and balance laws on compressible and incompressible thermoviscous fluent continua is demonstrated due to presence of angular velocities and angular accelerations arising from time varying rotation rates when the deforming fluent continua offer rotational inertial resistance. The fluent continua are considered homogeneous and isotropic. Model problem studies are considered in a follow-up paper. 展开更多
关键词 Non-Classical Continuum Mechanics internal Rotation Rates Angular Velocities Angular Accelerations Rotational Inertia Balance of Moment of Moments Thermoviscous Fluent Continua
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NCCT for Micropolar Solid and Fluid Media Based on Internal Rotations and Rotation Rates with Rotational Inertial Physics: Model Problem Studies
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作者 Karan S. Surana Jacob K. Kendall 《Applied Mathematics》 2023年第9期612-651,共40页
This paper presents model problem studies for micropolar thermoviscoelastic solids without memory and micropolar thermoviscous fluid using micropolar non-classical continuum theories (NCCT) based on internal rotations... This paper presents model problem studies for micropolar thermoviscoelastic solids without memory and micropolar thermoviscous fluid using micropolar non-classical continuum theories (NCCT) based on internal rotations and rotation rates in which rotational inertial physics is considered in the derivation of the conservation and balance laws (CBL). The dissipation mechanism is due to strain rates as well as rotation rates. Model problems are designed to demonstrate and illustrate various significant aspects of the micropolar NCCT with rotational inertial physics considered in this paper. In case of micropolar solids, the translational and rotational waves are shown to coexist. In the absence of microconstituents (classical continuum theory, CCT) the internal rotations are a free field, hence have no influence on CCT. Absence of gradients of displacements and strains in micropolar thermoviscous fluid medium prohibits existence of translational waves as well as rotational waves even though the appearance of the mathematical model is analogous to the solids, but in terms of strain rates. It is shown that in case of micropolar thermoviscous fluids the BAM behaves more like time dependent diffusion equation i.e., like heat conduction equation in Lagrangian description. The influence of rotational inertial physics is demonstrated using BLM as well as BAM in the model problem studies. 展开更多
关键词 MICROPOLAR internal Rotations internal Rotation Rates Translational Waves Rotational Waves DISSIPATION Thermoviscous Rotational Inertial Physics
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Theoretical Investigation on Internal Leakage and Its Effect on the Efficiency of Fluid Switcher-Energy Recovery Device for Reverse Osmosis Desalting Plant 被引量:2
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作者 乞炳蔚 王越 +3 位作者 王照成 张燕平 徐世昌 王世昌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第11期1216-1223,共8页
This work is focused on the theoretical investigation of internal leakage of a newly developed pi lotscale fluid switcherenergy recovery device (FSERD) for reverse osmosis (RO) system. For the purpose of in creasi... This work is focused on the theoretical investigation of internal leakage of a newly developed pi lotscale fluid switcherenergy recovery device (FSERD) for reverse osmosis (RO) system. For the purpose of in creasing FSERD efficiency and reducing the operating cost of RO, it is required to control the internal leakage in a low level. In this work, the internal leakage rates at different leakage gaps and retentate brine pressures are investigated by computational fluid dynamics (CFD) method and validating experiments. It is found that the internal leak age has a linear relationship with the retentate brine pressure and a polynomial relationship with the scale of leakage gap. The results of the present work imply that low internal leakage and high retentate brine pressure bring benefits to achieve high FSRD efficiency. 展开更多
关键词 internal leakage rate fluid switcher-energy recovery device computational fluid dynamics energytransfer efficiency
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A Research for Regional Contribution Rate of Internal Source and External Source of PM_(2.5) Based on Set Pair Analysis Method 被引量:1
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作者 Zhou Yejing Zhou Jingxuan Xiao Renbin 《Meteorological and Environmental Research》 CAS 2016年第2期36-40,44,共6页
A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis( SPA) method is proposed to calculate the con... A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis( SPA) method is proposed to calculate the contribution rate of PM2.5in Dongguan City. Due to geographic,meteorological factors and the low concentration of air pollutants in Qingxi area,the PM2.5in this place is mainly contributed by the regional transport of air pollutants from other inside areas of Dongguan,and less affected by the outside of Dongguan. So the concentration of PM2.5in Qingxi area can reflect the Dongguan's basic background concentration of PM2.5. On the basis of the basic background concentration,firstly the concentration of each pollutant components is divided into the internal part and the mixed part. Secondly using the source apportionment samples of five monitoring sites in Dongguan we can respectively construct a sample set A and an evaluation set B. Thirdly the SPA is operated onto the mixed part in terms of set B.At last the connection degree between the concentration of each pollutant components and external source and internal source will be calculated,that is the contribution rate. The research reveals that the contribution rate of internal source and external source of PM2.5in Dongguan City is 83%and 17% respectively,which roughly met expectations. This method is simple and effective and it can provide a reference for the government taking reduction measures to control PM2.5pollutants emission. 展开更多
关键词 Set Pair Analysis Connection degree PM2.5 internal source External source Contribution rate
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Reducing the Internal Difference Error Rate in Hospital Pharmacies:From the Angle of Quality Control Circle 被引量:1
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作者 Wang Shuling Lei Yingzi +2 位作者 Liu Linchuan Wang Ruili He Yalan 《Asian Journal of Social Pharmacy》 2020年第2期73-82,共10页
Objective To improve the management level of pharmacy dispensing center,reduce dispensing errors and promote the safety of drug use.Methods Hospital pharmacies could be managed according to the theory of quality contr... Objective To improve the management level of pharmacy dispensing center,reduce dispensing errors and promote the safety of drug use.Methods Hospital pharmacies could be managed according to the theory of quality control circle(QCC).Based on the ten steps of QCC,the internal difference error rate in pharmacies could be reduced.Results and Conclusion The error rate of pharmacies was reduced from 2.74‰to 0.57‰,and the goal achievement rate was 108.466.Besides,the progress rate reached 84.82%.The abilities of circle members were improved,and the operation of pharmacy was more standardized.The activity of QCC is helpful to reduce the internal difference error rate,improve the operation level of pharmacy and ensure the safety of drug use. 展开更多
关键词 quality control circle(QCC) medical institution internal difference error rate
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Testification on Effectiveness of Average or Weight-added Internal Rate of Return
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作者 Xiaoshui Yu Guojie Zhao 《Chinese Business Review》 2006年第1期60-63,共4页
It seems that an effective way of how to make the right choice of Various investment projects is based on the theory of average internal income rate, or the theory of weight-added internal income rate. With several ex... It seems that an effective way of how to make the right choice of Various investment projects is based on the theory of average internal income rate, or the theory of weight-added internal income rate. With several examples of numerical value, this paper proves that this method is not as effective as expected, but indirectly testifies that only with the principle of maximization of NPV that independent projects can be the best combination of projects with limited investment that is achieved. 展开更多
关键词 average internal income rate weight-added internal income rate combination of independent projects testification of effectiveness
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Modelling the Iranian Petroleum Contract fiscal regime using bargaining game theory to guide contract negotiators 被引量:1
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作者 Mehdi Keshavarz Hossein Iranmanesh Reza Dehghan 《Petroleum Science》 SCIE CAS CSCD 2021年第6期1887-1898,共12页
Based on Iran's sixth development plan,the country's oil and gas industry requires an investment of about$200 bn in the next five years to increase production.The Iranian government,to attract and motivate int... Based on Iran's sixth development plan,the country's oil and gas industry requires an investment of about$200 bn in the next five years to increase production.The Iranian government,to attract and motivate international oil company investment in their oil and gas fields,has presented a new type of risk service contract:the Iranian Petroleum Contract(IPC).This paper summarizes the features of the IPC and presents mathematical models of its fiscal regime for the benefit and guidance of both the National Iranian Oil Company(NIOC)and the contractors.Next,adopting bargaining game theory provides a mathematical model for reaching a win-win situation between the NIOC and the contractor.Finally,a numerical example is given and a sensitivity analysis performed to illustrate the implementation of the proposed models.The contractor and the NIOC may use these models when preparing their proposal and in the course of actual negotiations to calculate their internal rate of return,remuneration fee,and net present value for developing the fields at different conditions of their bargaining power,and derive a logical bargain to protect their best possible interests. 展开更多
关键词 Iranian petroleum contract Fiscal regime internal rate of return Bargaining game theory
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On the feasibility of re-stimulation of shale wells 被引量:4
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作者 Mohammad O.Eshkalak Umut Aybar Kamy Sepehrnoori 《Petroleum Science》 SCIE CAS CSCD 2015年第3期553-559,共7页
As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has ris... As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios: (1) re-fracturing versus no re- fracturing, (2) combination of re-fracturing and drilling new wells, and (3) time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays. 展开更多
关键词 Economic analysis - Unconventional shaleassets Hydraulic re-fracturing - Net present value internal rate of return
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A techno-economic analysis of aquaculture business in Ogun State,Nigeria
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作者 R. O. KAREEM S. B. WILLIAMS 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第2期415-420,共6页
Fish supplies 25% of the total protein source in developing countries. A techno-economic analysis was performed for developing a good business proposal for aquaculture loans to enhance aquaculture development in Niger... Fish supplies 25% of the total protein source in developing countries. A techno-economic analysis was performed for developing a good business proposal for aquaculture loans to enhance aquaculture development in Nigeria. A case study of catfish Clarias gariepinus framing was conducted in Abeokuta North Local Government of Ogun State, Nigeria. The results show that the fixed cost is N18 338 per year, and the variable cost is N459 700 per year, accounting for the largest amount of the total; therefore, a profit of N43 289 per month can be made. Sensitivity analysis was performed to assess any risk(s) that associated with unfavorable changes in government policy with particular reference to monetary policy. Positive net present value shows that the investment in fish farm is economically feasible and the net investment ratio is 3.52. Also, the benefit-cost ratio is 2.17. The internal rate of return (IRR) is 21% showing that the enterprise is able to offset the interest being charged on the loan. It is therefore worthwhile to invest into fish farm business in the study area. The study suggests that to better sustain the local aquaculture business, the government should create a good conducive environment to foster development of the fish farming. Government intervention is urgently needed to solve problems such as in traditional land tenure, grant credit facilities and subsidies, to enhance the aquacultural development in the country. 展开更多
关键词 AQUACULTURE net present value B-C ratio net-investment-ratio internal rate of return
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Measuring the model risk-adjusted performance of machine learning algorithms in credit default prediction
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作者 Andrés Alonso Robisco JoséManuel CarbóMartínez 《Financial Innovation》 2022年第1期1930-1964,共35页
Implementing new machine learning(ML)algorithms for credit default prediction is associated with better predictive performance;however,it also generates new model risks,particularly concerning the supervisory validati... Implementing new machine learning(ML)algorithms for credit default prediction is associated with better predictive performance;however,it also generates new model risks,particularly concerning the supervisory validation process.Recent industry surveys often mention that uncertainty about how supervisors might assess these risks could be a barrier to innovation.In this study,we propose a new framework to quantify model risk-adjustments to compare the performance of several ML methods.To address this challenge,we first harness the internal ratings-based approach to identify up to 13 risk components that we classify into 3 main categories—statistics,technology,and market conduct.Second,to evaluate the importance of each risk category,we collect a series of regulatory documents related to three potential use cases—regulatory capital,credit scoring,or provisioning—and we compute the weight of each category according to the intensity of their mentions,using natural language processing and a risk terminology based on expert knowledge.Finally,we test our framework using popular ML models in credit risk,and a publicly available database,to quantify some proxies of a subset of risk factors that we deem representative.We measure the statistical risk according to the number of hyperparameters and the stability of the predictions.The technological risk is assessed through the transparency of the algorithm and the latency of the ML training method,while the market conduct risk is quantified by the time it takes to run a post hoc technique(SHapley Additive exPlanations)to interpret the output. 展开更多
关键词 Artificial intelligence Machine learning Credit risk INTERPRETABILITY BIAS internal ratings based model IRB model Natural language processing NLP
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Corporate Probability of Default(PD)Modelling for Banks in Emerging Economies:A Case Study of Zimbabwe Stock Exchange(ZSE)Listed Counters
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作者 Ephraim Matanda Vharawei Matanda Ropafadzo Mhizha 《Journal of Modern Accounting and Auditing》 2021年第2期110-124,共15页
The paper extends Merton’s Probability of Default(PD)model to the case for transaction costs or market friction for estimation of the PDs of listed banking corporations.A closed form formula for the PD model is obtai... The paper extends Merton’s Probability of Default(PD)model to the case for transaction costs or market friction for estimation of the PDs of listed banking corporations.A closed form formula for the PD model is obtained and validated using financial data drawn from banks listed on the Zimbabwe Stock Exchange(ZSE).It has been observed that most corporations in emerging economies have been finding it extremely difficult to list,continue listed or manage risk emanating from credit exposures undertaken.In the absence of risk the role of the financial sector of an economy to efficiently and effectively allocate resources between the public and private sectors would be simplified,economically and rationally determined.Reliable or precise computation of the Probability of Default(PD)of a borrower is one of the most critical tasks in credit risk management for commercial banks that were applying the Internal Rating Based Approach(IRBA)under the Basel Capital Accords Ⅱ and Ⅲ frameworks.The study sought to develop a Probability of Default(PD)model that banking corporations in emerging economies such as Zimbabwe could adopt and implement in the Multiple Currency System(MCS)in their desire to grow and develop through their lending businesses.The research study adopted a PD model similar to the Asset Valuation Model(AVM)by Merton(1974)and initially extended by Black-Scholes(1973)and Crouhy et al.(2000)and applied it on a basket of Zimbabwe Stock Exchange listed counters after having adjusted the model for the transaction cost variable.The study therefore succeeded in coming up with a PD model that was worth adopting and implementing by Zimbabwe Stock Exchange(ZSE)listed corporations in their desire to grow towards sustainable development.It was realised that a contemporary PD model adjusted for transaction cost is pertinent for reflection of practical conditions banks face in estimation of their risk metrics such as PD.Transaction costs faced by banks in emerging economies are very huge that they cannot be assumed to be insignificant when it comes to valuation of PDs of banking corporations.The inclusion of transaction costs in estimation of PDs of ZSE listed banks is likely to create a paradigm shift in financial theory on risk metrics in the modern world.The study ends by recommending the need for all Zimbabwean listed corporations to adopt and implement an AVM adjusted for transaction costs if they were to successfully measure and manage both their investment and credit exposure endeavours in the multiple currency system period. 展开更多
关键词 Probability of Default(PD) transaction costs emerging economies credit exposures internal rating based approach Multiple Currency system(MCS)
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Reliability and validity of the Chinese version of the Scale for Assessment and Rating of Ataxia 被引量:4
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作者 TAN Song NIU Hui-xia ZHAO Lu GAO Yuan LU Jia-meng SHI Chang-he Chandra Avinash WANG Rui-hao XU Yu-ming 《Chinese Medical Journal》 SCIE CAS CSCD 2013年第11期2045-2048,共4页
Background The Scale for the Assessment and Rating of Ataxia (SARA) was shown to be a reliable and valid measurement for patients with spinocerebellar ataxia (SCA). The Brazilian version and the Japanese version o... Background The Scale for the Assessment and Rating of Ataxia (SARA) was shown to be a reliable and valid measurement for patients with spinocerebellar ataxia (SCA). The Brazilian version and the Japanese version of SARA were favorable for good reliability and validity. This study aimed to translate SARA into Chinese and test its reliability and validity in measurement of cerebellar ataxia. Methods SARA was translated into Chinese. A total 39 patients with degeneration cerebellar ataxia were evaluated independently by two neurologists with the Chinese version of SARA. Then the patients were evaluated by one of above neurologists with International Cooperative Ataxia Rating Scale (ICARS). The statistical analyses were performed using SPSS 17.0 for Windows. Results The Cronbach's alpha coefficient of the Chinese version of SARA was 0.78, which represents a good internal consistence. The correlation coefficient of the Chinese version of SARA scores between the two evaluators was 0.86, illustrating that the inter-rater reliability of Chinese version of SARA was good. The correlation coefficient between the Chinese version of SARA and ICARS was 0.91, illustrating that the criterion validity of Chinese version of SARA was not bad. Conclusions The Chinese version of SARA is reliable and effective for the assessment of degeneration cerebellar ataxia. Compared with ICARS, the evaluation of Chinese version of SARA is more objective, the assessment time is shortened, and the maneuverability is better. 展开更多
关键词 Scale for Assessment and rating of Ataxia International Cooperative Ataxia rating Scale reliability validity
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Observation of tiny polarization rotation rate in total internal reflection via weak measurements 被引量:2
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作者 CHENGQUAN MI SHIZHEN CHEN +3 位作者 XINXING ZHOU KAI TIAN HAILU LUO SHUANGCHUN WEN 《Photonics Research》 SCIE EI 2017年第2期92-96,共5页
In this paper,we examine the tiny polarization rotation effect in total internal reflection due to the spin–orbit interaction of light.We find that the tiny polarization rotation rate will induce a geometric phase gr... In this paper,we examine the tiny polarization rotation effect in total internal reflection due to the spin–orbit interaction of light.We find that the tiny polarization rotation rate will induce a geometric phase gradient,which can be regarded as the physical origin of photonic spin Hall effect.We demonstrate that the spin-dependent splitting in position space is related to the polarization rotation in momentum space,while the spin-dependent splitting in momentum space is attributed to the polarization rotation in position space.Furthermore,we introduce a quantum weak measurement to determine the tiny polarization rotation rate.The rotation rate in momentum space is obtained with 118 nm,which manifests itself as a spatial shift,and the rotation rate in position space is achieved with 38 μrad∕λ,which manifests itself as an angular shift.The investigation of the polarization rotation characteristics will provide insights into the photonic spin Hall effect and will enable us to better understand the spin–orbit interaction of light. 展开更多
关键词 rate Observation of tiny polarization rotation rate in total internal reflection via weak measurements
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Hydrodynamic behavior of an internally circulating fluidized bed with tubular gas distributors 被引量:1
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作者 Wenli Zhao Tiefeng Wang +1 位作者 Chenjing Wang Zuoliang Sha 《Particuology》 SCIE EI CAS CSCD 2013年第6期664-672,共9页
To better understand the hydrodynamic behavior of an internally circulating fluidized bed, solids holdup in the down-comer (Eso), solids circulation rate (Gs) and gas bypassing fraction (from down-comer to riser ... To better understand the hydrodynamic behavior of an internally circulating fluidized bed, solids holdup in the down-comer (Eso), solids circulation rate (Gs) and gas bypassing fraction (from down-comer to riser y^R, and from riser to down-comer yRD) were experimentally studied. The effects of gas velocities in the riser and in the down-comer (UR and UD), orifice diameter in the draft tube (dor), and draft tube height (HR) were investigated. Experimental results showed that increase of gas velocities led to increase in Gs and yDR, and slight decrease in yeD. Larger orifice diameter on the draft tube led to higher 8sD, Gs and yDR, but had insignificant influence on YRD. with increasing draft tube height, both Gs and YDR first increased and then decreased, while yRD first decreased and then increased. Proposed correlations for predicting the hydrodynamic parameters agreed reasonably well with experimental values. 展开更多
关键词 internally circulating fluidized bed Solids holdup Solids circulation rate Gas bypassing fraction
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Biomass energy cost and feasibility of gasifier based biomass power generation system
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作者 Khambalkar V P Kankal U S +1 位作者 Karale D S Gangde C N 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2013年第4期55-63,共9页
The present research work has been carried out on biomass based on 10 kW capacity gasifier power generation system installed at College of Agricultural Engineering and Technology,Dr.Panjabrao Deshmukh Agricultural Uni... The present research work has been carried out on biomass based on 10 kW capacity gasifier power generation system installed at College of Agricultural Engineering and Technology,Dr.Panjabrao Deshmukh Agricultural University(Dr.PDKV),Akola Maharashtra,India.The main objectives were to evaluate various costs and benefits involved in the power generation system.The costs of energy per unit were calculated for the first year of operation.The economics of gasifier based power generation system and thereby the feasibility of the system was examined by estimating per unit cost,Net Present Value(NPV),Benefit Cost Ratio(BCR),Internal Rate of Return(IRR)and payback period.The discount cash flow method was used to find out the IRR.In the present analysis,three costs viz.,installed capital cost,operation and maintenance cost,and levelised replacement cost were examined for the evaluation of the power generation per unit.Discount rate on investment in case of subsidy(Case I)and in case without subsidy(Case II)for installation cost of system was considered as 12.75%.The BCR comes in Case I for operating duration of 22 h,20 h,and 16 h are 1.24,1.18,and 1.13,respectively.Similarly for Case II BCR comes 1.44,1.38,and 2.39.The IRR comes in Case I for operating duration of 22 h,20 h,and 16 h are 26%,22%,and 19%,respectively.Similarly for Case II,IRR comes 52%,44%,and 39%for operating duration of 22 h,20 h,and 16 h,respectively.The payback period in the present analysis was worked out.The payback period for biomass based gasifier power generation system was observed to be for Case I from three to four years and for Case II it was one to two years. 展开更多
关键词 cost of biomass energy biomass power generation system discounted cash flow benefit cost ratio net present value payback period internal rate of return
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Thermo-Mechanically Coupled Thermo-Elasto-Visco-Plastic Modeling of Thermo-Induced Shape Memory Polyurethane at Finite Deformation 被引量:4
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作者 Jian Li Qian-hua Kan +2 位作者 Ze-bin Zhang Guo-zheng Kang Wenyi Yan 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2018年第2期141-160,共20页
A series of monotonic tensile experiments of thermo-induced shape memory polyurethane (TSMPU) at different loading rates were carried out to investigate the interaction between the internal heat production and the m... A series of monotonic tensile experiments of thermo-induced shape memory polyurethane (TSMPU) at different loading rates were carried out to investigate the interaction between the internal heat production and the mechanical deformation. It is shown that the tem- perature variation on the surfaces of the specimens due to the internal heat production affects the mechanical properties of TSMPU remarkably. Then, based on irreversible thermodynamics, the Helmholtz free energy was decomposed into three parts, i.e., the instantaneous elastic free energy, visco-plastic free energy and heat free energy. The total deformation gradient was decomposed into the mechanical and thermal parts, and the mechanical deformation gradient was further divided into the elastic and visco-plastic components. The Hencky's logarithmic strain was used in the current configuration. The heat equilibrium equation of internal heat production and heat exchange was derived in accordance with the first and second thermodynamics laws. The temperature of specimens was contributed by the internal heat production and the ambient temperature simultaneously, and a thermo-mechanically coupled thermo-elasto-visco-plastie model was established. The effect of temperature variation of specimens on the mechanical properties of the material was considered in this work. Finally, the capability of the proposed model was validated by comparing the simulated results with the corresponding experimental data of TSMPU. 展开更多
关键词 Shape memory polyurethane Thermo-mechanical coupling Rate dependence internal heat production Finite deformation
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