This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of v...This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.展开更多
为了实现光伏电池的最大功率点跟踪(Maximum Power Point Tracking,MPPT),在分析现有方法的优缺点基础上,提出了一种基于最小二乘支持向量机(Least Squares Support Vector Machine,LSSVM)的MPPT实现方法。为证明该方法的有效性,在Matla...为了实现光伏电池的最大功率点跟踪(Maximum Power Point Tracking,MPPT),在分析现有方法的优缺点基础上,提出了一种基于最小二乘支持向量机(Least Squares Support Vector Machine,LSSVM)的MPPT实现方法。为证明该方法的有效性,在Matlab/Simulink中,搭建了光伏电池仿真模型,分析了光伏电池的输出特性。结合LSSVM工具箱,采用交叉验证方法实现LSSVM的参数寻优,并对LSSVM用于MPPT的方法进行了仿真。仿真结果表明,该方法能够较准确地实现最大功率点处的输出电压和电流的跟踪,与其他方法相比,能够有效避免系统在最大功率点处振荡运行。展开更多
In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart’s group B as bed material.The simulation...In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart’s group B as bed material.The simulations were performed using a homogeneous drag model as well as a structure dependent drag model based on the energy minimization multi-scale method(EMMS).The results are compared with experimental data from literature as well as experiments.The simulations with the EMMS based drag model show a good agreement of the time-averaged axial solids concentration,circulation rate and riser pressure drop.Furthermore,a lower grid sensitivity is observed compared to the homogeneous drag model.In contrast to the conventional drag model a dense bottom zone is predicted by the EMMS based drag model.An overprediction of the solid concentration in the dense bottom zone is presumably due to an overprediction of the cluster diameter that is calculated using an empirical cluster diameter correlation.This shows the necessity for a new meso-scale cluster correlation for the simulation of Geldart B particles.Furthermore,the results of the time-averaged radial solids concentration differ from the expectations of a core-annulus flow indicating that a mesh refinement at the walls is necessary.Finally,the importance of using a realistic particle size distribution is identified.展开更多
Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric whee...Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric wheelchairs, electric trolleybuses, medical carts, military engines, personal sports craft, mobility devices and other self propelled equipment. Up to now, many researches have focused on the development of the power module in the Fuel cell vehicles (FCVs) and the components of these systems such as membranes, bipolar plates, and electrodes. However, our work in this study focuses on operating the integrated fuel cell power module system efficiently for various operating conditions such as pressure, relative humidity and operating modes. In our validation we have utilized PEMFC single cell, with active area geometry 16 cm2 and of 120 cm2. Some results obtained in our study shown significant performance indicators for PEMFC stack (composed of 2 cells and 4 cells in a series) at different humidification levels.展开更多
文摘This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.
文摘为了实现光伏电池的最大功率点跟踪(Maximum Power Point Tracking,MPPT),在分析现有方法的优缺点基础上,提出了一种基于最小二乘支持向量机(Least Squares Support Vector Machine,LSSVM)的MPPT实现方法。为证明该方法的有效性,在Matlab/Simulink中,搭建了光伏电池仿真模型,分析了光伏电池的输出特性。结合LSSVM工具箱,采用交叉验证方法实现LSSVM的参数寻优,并对LSSVM用于MPPT的方法进行了仿真。仿真结果表明,该方法能够较准确地实现最大功率点处的输出电压和电流的跟踪,与其他方法相比,能够有效避免系统在最大功率点处振荡运行。
基金the financial support of the German Research Foundation(DFG),project number HE 4526/21-1.
文摘In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart’s group B as bed material.The simulations were performed using a homogeneous drag model as well as a structure dependent drag model based on the energy minimization multi-scale method(EMMS).The results are compared with experimental data from literature as well as experiments.The simulations with the EMMS based drag model show a good agreement of the time-averaged axial solids concentration,circulation rate and riser pressure drop.Furthermore,a lower grid sensitivity is observed compared to the homogeneous drag model.In contrast to the conventional drag model a dense bottom zone is predicted by the EMMS based drag model.An overprediction of the solid concentration in the dense bottom zone is presumably due to an overprediction of the cluster diameter that is calculated using an empirical cluster diameter correlation.This shows the necessity for a new meso-scale cluster correlation for the simulation of Geldart B particles.Furthermore,the results of the time-averaged radial solids concentration differ from the expectations of a core-annulus flow indicating that a mesh refinement at the walls is necessary.Finally,the importance of using a realistic particle size distribution is identified.
基金The Center for Renewable Energies Development (CDER)The General Directorate for Scientific Research and Tech- nological Development (DG-RSDT)+1 种基金The Na- tional Observatory of the Environment and the Durable Development (ONEDD)The Ministry of Town and Country Planning and the Environment
文摘Fuel cell powered vehicles have been developed as another alternative to internal combustion engine powered vehicles for some applications including passenger cars, buses, trains, motorcycles, forklifts, electric wheelchairs, electric trolleybuses, medical carts, military engines, personal sports craft, mobility devices and other self propelled equipment. Up to now, many researches have focused on the development of the power module in the Fuel cell vehicles (FCVs) and the components of these systems such as membranes, bipolar plates, and electrodes. However, our work in this study focuses on operating the integrated fuel cell power module system efficiently for various operating conditions such as pressure, relative humidity and operating modes. In our validation we have utilized PEMFC single cell, with active area geometry 16 cm2 and of 120 cm2. Some results obtained in our study shown significant performance indicators for PEMFC stack (composed of 2 cells and 4 cells in a series) at different humidification levels.
