Avoid Contamination in Soybean (Glycine Max, L. [Merrill]) Microspores Culture

Microspore culture is done to obtain pure strains. The purpose of soybean microspore culture to obtainquality seeds. Two important step that must be done is isolation of microspores in starvation medium andsubculture into embryogenesis medium. Many factors contributing to the contamination of soybeanmicrospore culture. Contamination in the B medium temperature 34 0C is more common than 4 0C. Vulnerableto contamination because of embryogenesis medium rich in nutrients. Bacterial contaminationcan be caused by internal contaminants such as shape of the anther. Other internal contaminants thatcause diseases such as fungi Colletotrichum truncatum and Phakopsora pachyrhizi. Antagonistic fungiwhich contaminate cultures that Trichoderma spp., Alternaria spp., Fusarium spp. Handling of contaminationis done by selecting the appropriate methods in order to remain viable microspores. Sterilization soybeanflower buds with 20% Tween for 10 minutes and then rinsed with distilled water. Moreover sterilizationwith 4% Hg Cl2 and 10% NaOCl for 10 minutes, rinsed with distilled water times, followed by 96%alcohol for 1 minute, can press up to 70% contamination

The United States COVID-19 Forecast Hub dataset

Academic researchers, government agencies, industry groups, and individuals have produced forecasts at an unprecedented scale during the COVID-19 pandemic. To leverage these forecasts, the United States Centers for Disease Control and Prevention (CDC) partnered with an academic research lab at the University of Massachusetts Amherst to create the US COVID-19 Forecast Hub. Launched in April 2020, the Forecast Hub is a dataset with point and probabilistic forecasts of incident cases, incident hospitalizations, incident deaths, and cumulative deaths due to COVID-19 at county, state, and national, levels in the United States. Included forecasts represent a variety of modeling approaches, data sources, and assumptions regarding the spread of COVID-19. The goal of this dataset is to establish a standardized and comparable set of short-term forecasts from modeling teams. These data can be used to develop ensemble models, communicate forecasts to the public, create visualizations, compare models, and inform policies regarding COVID-19 mitigation. These open-source data are available via download from GitHub, through an online API, and through R packages

High redox and performance stability of layered SmBa0.5Sr 0.5Co1.5Cu0.5O5+?? perovskite cathodes for intermediate-temperature solid oxide fuel cells

Cobalt-containing cathodes often encounter problems such as high thermal expansion coefficients (TEC) and poor stability, making them unsuitable for practical use as cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This study focuses on the effects of Cu doping in the Co site of SmBa0.5Sr0.5Co2O5+?? in terms of structural characteristics, electrical properties, electrochemical performance, redox properties, and performance stability as an IT-SOFC cathode material. The TEC value of a SmBa0.5Sr0.5Co 1.5Cu0.5O5+?? (SBSCCu50) sample is 12.8 ?? 10-6 K-1, which is lower than that (13.7 ?? 10-6 K-1) of a SmBa0.5Sr0.5Co 2O5+?? (SBSCO) sample at 700 ??C. SBSCCu50 showed higher redox stability at lower p(O2) and a more stable cell power output while retaining desirable electrochemical performance, as compared with SBSCO. SBSCCu50 displayed reduced TEC values and enhanced redox and performance stability, as well as satisfactory electrical properties and electrochemical performance under typical fuel cell operating conditions. The results indicate that SBSCCu50 is a promising material as a cathode for IT-SOFCs.close6

Optimization of Sr content in layered SmBa1-xSrxCo2O5+delta perovskite cathodes for intermediate-temperature solid oxide fuel cells

Cation ordered perovskites have been recognized as advanced cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This study focuses on the effects of Sr substitution on crystal characteristics, electrical properties, and electrochemical performance of SmBa1-xSrxCo2O5+delta (x = 0, 0.25, 0.5, 0.75, and 1.0) as an IT-SOFC cathode material. The electrical conductivity improves with increasing Sr content due to the greater amount of electronic holes originated from the increased interstitial oxygen. The area specific resistances (ASRs) of SmBa1-xSrxCo2O5, decrease with Sr content up to x = 0.75 and increase abruptly for x = 1. For x = 0.75, the lowest ASR value, 0.138 Omega cm(2), and the highest single cell performance, 1.039 W cm(-2) at 600 degrees C, are obtained. These results indicate that SmBa1-xSrxCo2O5+delta is optimized at x = 0.75 in terms of obtaining the best performance for IT-SOFCs.close121

Effect of Fe Doping on Layered GdBa0.5Sr0.5Co2O5+delta Perovskite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

Layered perovskite cathode materials have received considerable attention for intermediate temperature solid oxide fuel cells (IT-SOFCs) because of their fast oxygen ion diffusion through pore channels and high catalytic activity toward the oxygen reduction reaction (ORR) at low temperatures. In this study, we have investigated the effects of Fe substitution for the Co site on electrical and electrochemical properties of a layered perovskite, GdBa0.5Sr0.5Co2-xFexO5+delta (x=0, 0.5, and 1.0), as a cathode material for IT-SOFCs. Furthermore, electrochemical properties of GdBa0.5Sr0.5CoFeO5+delta-yGDC (y=0, 20, 40, and 50 wt%) cathodes were evaluated to determine the optimized cell performance. At a given temperature, the electrical conductivity and the area-specific resistances (ASRs) of GdBa0.5Sr0.5Co2-x FexO5+delta decrease with Fe content. The lowest ASR of 0.067 Omega center dot cm(2) was obtained at 873K for the GdBa0.5Sr0.5CoFeO5+delta. The GdBa0.5Sr0.5CoFeO5+delta composite with 40 wt% GDC was identified as an optimum cathode material, showing the highest maximum power density (1.31 W/cm(2)) at 873 K, and other samples also showed high power density over 1.00 W/cm(2).close5

Various Types of Applications with Double Perovskite Structure

Perovskite oxides with variable oxygen non-stoichiometry play a prominent role in many fields, including fuel cells, catalysis and gas storage. One interesting class of materials for solid oxide fuel cells (SOFCs) are cation ordered layered perovskite oxides due to their mixed ionic and electronic conductivity and fast oxygen kinetics. Even though progress has been made in cathode materials to lower the cathodic polarization, still it is also important for fuel cell technology to achieve highly efficient anode that realize long term stability with enhanced tolerance to carbon buildup (coking) and sulfur contamination (poisoning) from hydrocarbon fuels. Here, we report identification of redox-stable cation layered perovskite anode, with superior electrochemical performance in both hydrogen and hydrocarbons. Further, double perovskite materials will have immediate and profound implications for a new generation of SOFCs, proton conducting SOFC, oxygen separation membranes, electrolyzers, as well as other processes involving oxygen/electron transport

Performance Characteristics of Automobile Air Conditioning Using the R134a/R1234yf Mixture

In this study, the energy and exergy of an automobile refrigeration system using R134a and R134a/R1234yf were analyzed experimentally with respect to outdoor air temperature and compressor speed. As outdoor air temperature increased from 32.5 °C to 37.5 °C, the coefficient of performance (COP) and total exergy destruction rate of the refrigeration system using Mix30 decreased by 5.19% and 25.8% on average, compared to that of the system using R134a. The exergy efficiency of the Mix30 refrigeration system was on average 21.8% higher than that of the R134a system. As the compressor rotating speed increased from 1000 to 2000 rpm, the cooling capacity of the refrigeration system using R134a and R134a/R1234yf increased, while the COP decreased. The COP and total exergy destruction rate of the refrigeration system using Mix30 decreased by 4.82% and 19.5%, compared to that of the system using R134a. The exergy efficiency of the Mix30 refrigeration system increased on average by 20.7%, compared to that of the R134a system. The total exergy destruction rate of the automobile refrigeration system using R134a/R1234yf decreased with increase in R1234yf, while exergy efficiency increased. In addition, the exergy destruction rate of the automobile refrigeration system decreased as the amount of R1234yf in the R134a/R1234yf automobile refrigeration system increased

Electrochemical and redox studies of Sm0.5Sr0.5Co1-xNbx (x = 0, 0.1) as cathode materials in intermediate temperature-solid oxide fuel cells

The perovskite-oxides, such as (La,Sr)CoO3 and (Ba,Sr)CoO3, have received much attention in recent years as cathode materials for intermediate temperature-solid oxide fuel cells (IT-SOFCs). In this study, we have investigated the structural, electrical, electrochemical, and redox properties of Sm0.5Sr0.5Co1-xNbxO3-?? (SSCNbx) cathodes under conditions relevant to IT-SOFC operation. The SSCNbx (x = 0, 0.1) oxides show gradually decreasing electrical conductivity with increasing Nb doping at the same temperature. The maximum power density of SSCNbx (x = 0.1) is lower than that of SSC; however, SSCNbx (x = 0.1) is more stable than SSC considering the thermodynamic behavior, as determined through redox isotherms. These results suggest that a Nb doped SSC perovskite is suitable, considering its high power density and reasonable redox stability, as an IT-SOFC cathode material.close0

Electrochemical properties of B-site Ni doped layered perovskite cathodes for IT-SOFCs

Offering fast oxygen reduction kinetics and high electrical conductivities relative to those of ABO3-type perovskite oxides, layered perovskite cathode materials have received considerable attention for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, we have investigated the effects of Ni substitution for the Co site in SmBa0.5Sr0.5Co2O5+?? in terms of structural characteristics, electrical properties, and electrochemical performance of SmBa0.5Sr0.5Co2-xNixO5+?? (x=0, 0.1, and 0.2) in relation to its application as an IT-SOFC cathode material. At the given temperature, the electrical conductivities of SmBa0.5Sr0.5Co2-xNixO5+?? (x=0, 0.1, and 0.2) decrease with increasing Ni content. For x=0.1, the lowest ASR value, 0.125??cm2, and the highest single cell performance, 1.78Wcm-2 at 600??C, are obtained.close0