Development of Advanced Biomass Cookstove and Performance Comparisons Using the Modified Star Rating Methodology

A disruptive approach to a fundamental process has been applied in a biomass combustion device with two variable speed fans to supply air for gasification and another for combustion processes,separately.Besides,the preheating of secondary air,required for combustion process was also ensured through annulus chamber before being fed into the combustion chamber.The turbulent flow and homogenous mixing were also ensured by controlling the flow rate resulting in the reduced emissions of carbon monoxide(CO)and fine particulate matter(PM 2.5,particulate matter having aerodynamic diameter<2.5 micron).The design approach applied here has also ensured the homogeneous mixing of preheated air with the volatiles,resulted in cleaner combustion.This arrangement has led to the emissions of PM2.5 and CO much better than those of the earlier cookstove models,and very close to that of a liquefied petroleum gas(LPG)stove.Further,the comparative analysis based on the modified star rating of total 15(14 are biomass and another LPG)cookstove models tested using the same standard methodology has been done and presented in this study.Based on the star rating,the performance of the LPG stove was found to be best and assigned as a 5-star product followed by the IITD model(4-star),while the other 13 models got different ratings starting from 1-star to 3-star,respectively.Also,the thermal performance of the IITD cookstove model is found to be the highest,while the emission characteristics are found to be the least among all biomass cookstove models,presented here.

Toward a stellar population catalog in the Kilo Degree Survey:The impact of stellar recipes on stellar masses and star formation rates

The Kilo Degree Survey(Ki DS)is currently the only sky survey providing optical(ugri)plus near-infrared(NIR,ZY H JKS)seeing matched photometry over an area larger than 1000 deg2.This is obtained by incorporating the NIR data from the VISTA Kilo Degree Infrared Galaxy(VIKING)survey,covering the same Ki DS footprint.As such,the Ki DS multi-wavelength photometry represents a unique dataset to test the ability of stellar population models to return robust photometric stellar mass(M_(*))and star-formation rate(SFR)estimates.Here we use a spectroscopic sample of galaxies for which we possess ugri ZY JHK_(s)“gaussianized”magnitudes from Ki DS data release 4.We fit the spectral energy distribution from the 9-band photometry using:(1)three different popular libraries of stellar population templates,(2)single burst,simple and delayed exponential star-formation history models,and(3)a wide range of priors on age and metallicity.As template fitting codes we use two popular softwares:Le Phare and CIGALE.We investigate the variance of the stellar masses and the star-formation rates from the different combinations of templates,star formation recipes and codes to assess the stability of these estimates and define some“robust”median quantities to be included in the upcoming Ki DS data releases.As a science validation test,we derive the mass function,the star formation rate function,and the SFR-M_(*)relation for a low-redshift(z<0.5)sample of galaxies,that result in excellent agreement with previous literature data.The final catalog,containing~290000 galaxies with redshift 0.01<z<0.9,is made publicly available.

Thermonuclear ^19F(p,α0)^16O reaction rate

The thermonuclear^19F（p,α0）16O reaction rate in the temperature region 0.007–10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations.Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature（e.g. 0.01 GK） our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ^1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data（Isoya et al., Nucl. Phys.7, 116（1958）） in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK,and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data.Asymptotic giant branch（AGB） stars evolve at temperatures below 0.2 GK, where the^19F（p,α）16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section（or S factor） data in the low energy region are therefore needed for astrophysical nucleosynthesis studies.