Thermally driven refrigerators: Equivalent low-dissipation three-heat-source model and comparison with experimental and simulated results

[EN]In order to investigate the performance of a class of thermally driven refrigerators, usually driven by low-grade thermal energy, a generic thermodynamic model of three-heat-source refrigerator without involving any specific heat-transfer law is put forward by adopting low-dissipation assumptions. Based on the proposed model, the analytical expressions for the coefficient of performance (COP) and cooling power of the system are derived in terms of well-defined dissipation parameters and contact time durations between the system and heat reservoirs. One essential parameter accounting for the size ratio of the two coupled subsystems inside the overall system is introduced in light of the practical meaning of the reversible entropy change. With the help of the aforementioned parameter, the optimal relation between the COP and cooling power is obtained. The optimal operation region and optimal construction of the overall system are further determined for the first time. In addition, the influences of the dissipation and temporal symmetries are discussed in detail, according to which the upper and lower bounds of the COP at maximum cooling power are firstly obtained under two extreme situations. Experimental and simulated data from previous reported works are collected to illustrate the validity and practical significance of the proposed model and associated results. A limit case is presented to highlight the generality of the model.National Natural Science Foundation of China ; Junta de Castilla y León of Spain ; University of Salamanca contract 2017/X005/1

Experimental and modeling study of high performance direct carbon solid oxide fuel cell with in situ catalytic steam-carbon gasification reaction

This research is supported by a grant (PolyU 152127/14E) from Research Grant Council, University Grants Committee, Hong Kong SAR, a grant from Environment and Conservation Fund (ECF 54/2015), Hong Kong SAR, and a grant from Research Institute for Sustainable Urban Development (RISUD) (1-ZVEA). We gratefully acknowledge the financial support of the National Science Foundation of China (Grant No. 51406091).In this paper, 2D models for direct carbon solid oxide fuel cells (DC-SOFCs) with in situ catalytic steam-carbon gasification reaction are developed. The simulation results are found to be in good agreement with experimental data. The performance of DC-SOFCs with and without catalyst are compared at different operating potential, anode inlet gas flow rate and operating temperature. It is found that adding suitable catalyst can significantly speed up the in situ steam-carbon gasification reaction and improve the performance of DC-SOFC with H2O as gasification agent. The potential of syngas and electricity co-generation from the fuel cell is also evaluated, where the composition of H2 and CO in syngas can be adjusted by controlling the anode inlet gas flow rate. In addition, the performance DC-SOFCs and the percentage of fuel in the outlet gas are both increased with increasing operating temperature. At a reduced temperature (below 800 °C), good performance of DC-SOFC can still be obtained with in-situ catalytic carbon gasification by steam. The results of this study form a solid foundation to understand the important effect of catalyst and related operating conditions on H2O-assisted DC-SOFCs.PostprintPeer reviewe

Production of human blood group B antigen epitope conjugated protein in Escherichia coli and utilization of the adsorption blood group B antibody

Additional file 1: Table S1. List of constructed plasmids, strains and primers used in the study. Figure S1. MALDI-TOF detection of MBPmut (a) and MBPmut-OPS (b)

Performance improvement of a direct carbon solid oxide fuel cell through integrating an Otto heat engine

This research is supported by the Natural Science Foundation of Zhejiang Province (Grant No. LQ14E060001), National Natural Science Foundation of China (Grant No. 51406091), a grant (PolyU 152127/14E) from Research Grant Council, University Grants Committee, Hong Kong SAR, a grant from Environment and Conservation Fund (ECF 54/2015), Hong Kong SAR, and the K. C. Wong Magna Fund in Ningbo University.A novel system consisting of an external heat source, a direct carbon solid oxide fuel cell (DC-SOFC), a regenerator and an air standard Otto cycle engine is proposed to improve the performance of the DC-SOFC. Considering the electrochemical/chemical reactions, ionic/electronic charge transport, mass/momentum transport and heat transfer, a 2D tubular DC-SOFC model shows that the overall heat released in the cell can be smaller than, equal to or larger than the heat required by the internal Boudouard reaction. Three different operating modes of the proposed system are identified, and accordingly, analytical expressions for the equivalent power output and efficiency of the proposed system are derived under different operating conditions. The modeling results show that the Otto heat engine can effectively recover the waste heat from the DC-SOFC for additional power production especially at large operating current density. Comprehensive parametric studies are conducted to investigate the effects of the different operating conditions of DC-SOFC on its performance and heat generation. The effects of compression ratio, internal irreversibility factor and power dissipation of the Otto heat engine on the system performance improvement are also studied.PostprintPeer reviewe

A compendium of genetic regulatory effects across pig tissues

The Farm Animal Genotype-Tissue Expression (FarmGTEx) project has been established to develop a public resource of genetic regulatory variants in livestock, which is essential for linking genetic polymorphisms to variation in phenotypes, helping fundamental biological discovery and exploitation in animal breeding and human biomedicine. Here we show results from the pilot phase of PigGTEx by processing 5,457 RNA-sequencing and 1,602 whole-genome sequencing samples passing quality control from pigs. We build a pig genotype imputation panel and associate millions of genetic variants with five types of transcriptomic phenotypes in 34 tissues. We evaluate tissue specificity of regulatory effects and elucidate molecular mechanisms of their action using multi-omics data. Leveraging this resource, we decipher regulatory mechanisms underlying 207 pig complex phenotypes and demonstrate the similarity of pigs to humans in gene expression and the genetic regulation behind complex phenotypes, supporting the importance of pigs as a human biomedical model.</p

Drug utilization patterns in the global context: A systematic review

Objectives Standard drug use indicators have been developed by the World Health Organization/International Network for Rational Use of Drugs (WHO/INRUD). The purpose of this systematic review was to examine and report the current status of health facilities in different regions of the world in terms of drug use based on WHO/INRUD core drug use indicators. Design Systematic review of the literature following PRISMA guidelines. Methods The INRUD bibliography, WHO archives, Google Scholar, Medline, PubMed, SpringerLink, ScienceDirect and Management Sciences for Health (MSH) resource databases were searched between 1985 and 2015 for studies -containing 12 WHO/INRUD core drug use indicators. Secondary data sources were also searched. Results Four hundred and sixty three studies were retrieved and 398 were excluded as they did not provide relevant information or fulfill the selection criteria. Sixty articles met the criteria and were selected for final review. With respect to prescribing indicators, studies of “drug use” showed mixed patterns across geographic regions. Overall trends in “patient-care” and “facility-specific” indicators were similar across most of the World Bank regions. However, based on the Index of Rational Drug Use (IRDU) values, East Asia and the Pacific region demonstrated relatively better drug use practices compared with other regions. Conclusions This systematic review revealed that the drug use practices in all regions of the world are suboptimal. A regulated, multi-disciplinary, national body with adequate funding provided by governments throughout the world are a basic requirement for coordination of activities and services, to improve the rational use of drugs at a local level

Three-stage integration system with solid oxide fuel cell, alkali metal thermal electric converter and organic Rankine cycle for synergistic power generation

During operation, solid oxide fuel cell releases quite a great part of hydrogen energy into waste heat, leading to energy waste and even functional component degradation. In this study, solid oxide fuel cell, alkali metal thermal electric converter and organic Rankine cycle are synergistically integrated as a three-stage integration system to gradually and efficiently utilize the waste heat. Accounting a variety of thermodynamic-electrochemical losses within the system, mathematical expressions of power output, energy efficiency, exergy destruction rate, and exergy efficiency for the integration system are deduced. The basic performance features and competitiveness of the integration system are revealed. The maximum power output density of the proposed system allows to be 12407.0 W m−2, which is approximately improved by 103.8 % compared to that of the stand-alone solid oxide fuel cell (6087.4 W m−2). Parametric studies demonstrate that an increase in operation temperature, operation pressure or radiation loss geometric factor enhances the integration system performance, while an increase in β″-alumina solid electrolyte thickness, proportional coefficient or pinch temperature ratio degrades the integration system performance. The results obtained can provide some theoretical support for designing or running such an actual three-stage integration system for efficient power generation

The performance analysis and multi-objective optimization of a typical alkaline fuel cell

National Natural Science Foundation, People's Republic of China [51076134]Based on the model of a typical alkaline fuel cell (AFC) with circulating potassium hydroxide (KOH) solution as electrolyte and oxygen as oxidant and the experimental data available in the current literature, thermodynamic-electrochemical analyses on the performance of the AFC are carried out, in which multi-irreversibilities such as charger-transfer, concentration and ohmic overpotentials are taken into account. Expressions for the power output and efficiency of the AFC are derived, from which the general performance characteristics of the AFC are discussed in detail. It is found that the power output and efficiency of the AFC first increase and then decrease as the electrolyte concentration is increased, and consequently, there exist the optimal electrolyte concentrations for different temperatures. It is also found that the power output is not a monotonic function of the electric current density while the efficiency is a monotonically decreasing function of the electric current density. According to the performance characteristic curves of the AFC, the optimal operation regions of some main parameters are determined. Moreover, a new multi-objective function is used to further optimize the characteristics of the AFC. Some significant results for the optimal design and operation of practical AFCs are obtained. (C) 2011 Elsevier Ltd. All rights reserved

Performance Evaluation and Parametric Optimum Criteria of an Irreversible Molten Carbonate Fuel Cell-Heat Engine Hybrid System

National Natural Science Foundation [51076134]; Fundamental Research Fund for the Central Universities, People's Republic of China [201112G006]The model of a hybrid system composed of a molten carbonate fuel cell (MCFC) and a heat engine is presented, in which multi-irreversibilities such as overpotentials in the electrochemical reaction, heat leak from the MCFC to the environment, non-perfect regeneration in the regenerator, and finite-rate heat transfer in the heat engine are taken into account. Expressions for the efficiency and power output of the system are analytically derived, from which the general characteristics of the hybrid system are revealed and the optimum criteria of some main parameters such as the current density, efficiency and power output are determined. The influence of the irreversible losses on the performance of the hybrid system is discussed. Moreover, a multi-objective function including both the efficiency and the power output is put forward and used to further subdivide the optimally operating region of the hybrid system. The results obtained here are very general and may be directly used to derive the various interesting conclusions of the hybrid systems operated under different special cases