对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分...对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分析结果表明,pheS基因序列群内种间的差异率在6.8%～34%之间,种内最大差异率可达3%,其变异率远高于16S rRNA基因,可作为该群内种水平鉴定的重要手段。展开更多
Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop cha...Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop channels, besides a third mixed configuration as to achieve in-between results regarding hydraulic performance. Friction factor correlations were provided with the channel Reynolds number ranging from 1175 to 8325. Two-dimensional (2D) mean velocity field was obtained by Particle Tracking Velocimetry (PTV) with Reynolds number equal to 3450. To the best of our knowledge, this is the first experimental study that quantified the complete 2D velocity field of a typical PHE channel. This value allowed comparison with literature results of Plate and Shell Heat Exchanger (PSHE) channels with the same Reynolds number. PSHE mean velocity field is highly heterogeneous as compared to the one obtained for PHE channels. Peak velocity magnitude in the PSHE center is 50% higher than its bulk velocity, whereas this value is only 15% higher in the PHE center. Pressure drop in PHE mixed channels cannot be approximated by averaging chevron angles: furrow flow prevailed in the specified conditions. The axial velocity is asymmetric regarding the vertical plane. Smooth streamlines prevail in the channel inlet. Recirculation zones at the channel exit affect pipe flow in the manifold outlet with swirling flow structures. The necessary length to obtain fully developed pipe flow at the channel outlet was estimated. Significant velocity components occur in the distribution areas and can limit the heat exchanger performance. The results reported herein are essential to understand how the PHE channel geometry affects the velocity field and, therefore, local heat transfer and dissipation processes.展开更多
The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be...The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.展开更多
文摘对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分析结果表明,pheS基因序列群内种间的差异率在6.8%～34%之间,种内最大差异率可达3%,其变异率远高于16S rRNA基因,可作为该群内种水平鉴定的重要手段。
文摘Channel flows of Plate Heat Exchangers (PHEs) were assessed by experiments with three different chevron angle arrangements in turbulent regime. Two chevron angles were selected to assess low and high pressure drop channels, besides a third mixed configuration as to achieve in-between results regarding hydraulic performance. Friction factor correlations were provided with the channel Reynolds number ranging from 1175 to 8325. Two-dimensional (2D) mean velocity field was obtained by Particle Tracking Velocimetry (PTV) with Reynolds number equal to 3450. To the best of our knowledge, this is the first experimental study that quantified the complete 2D velocity field of a typical PHE channel. This value allowed comparison with literature results of Plate and Shell Heat Exchanger (PSHE) channels with the same Reynolds number. PSHE mean velocity field is highly heterogeneous as compared to the one obtained for PHE channels. Peak velocity magnitude in the PSHE center is 50% higher than its bulk velocity, whereas this value is only 15% higher in the PHE center. Pressure drop in PHE mixed channels cannot be approximated by averaging chevron angles: furrow flow prevailed in the specified conditions. The axial velocity is asymmetric regarding the vertical plane. Smooth streamlines prevail in the channel inlet. Recirculation zones at the channel exit affect pipe flow in the manifold outlet with swirling flow structures. The necessary length to obtain fully developed pipe flow at the channel outlet was estimated. Significant velocity components occur in the distribution areas and can limit the heat exchanger performance. The results reported herein are essential to understand how the PHE channel geometry affects the velocity field and, therefore, local heat transfer and dissipation processes.
基金MoES (Govt of India)for his financial assistance to our project (GPP364).
文摘The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.
