An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution. The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid...An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution. The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated. It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples. The corrosion current density for bare magnesium, phytic acid conversion coated magnesium, and post-coating heat treated magnesium was calculated to be 2.48 ×10^-5, 1.18×10^-6, and 9.27 × 10^7 A/cm^2, respectively. The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium. The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.展开更多
The fiber reinforced plastics (FRPs) are being used widely in the most diverse applications ranging from the aerospace to the sports goods industry. Drilling in particular is important to facilitate the assembly opera...The fiber reinforced plastics (FRPs) are being used widely in the most diverse applications ranging from the aerospace to the sports goods industry. Drilling in particular is important to facilitate the assembly operations of structurally intricate composite products. The drilling of holes in FRPs leads to drilling induced damage which is an important research area. The researchers worldwide have tried to minimize the damage by optimizing the operating variables, and tool designs as well as by developing unconventional methods of hole making. Most of the work done so far has been experimental in nature with little or no focus on numerical simulation of the drilling behavior of FRPs. In the present research endeavor, a finite element model has been developed to investigate the drilling induced damage of FRP laminates.展开更多
We report a comparative study on photo-crystallization in a-Se95 Te5 and a-Se95In5 alloys. The photo-crystallization is achieved by a shining white line on the thin films of these alloys in vacuum for different exposu...We report a comparative study on photo-crystallization in a-Se95 Te5 and a-Se95In5 alloys. The photo-crystallization is achieved by a shining white line on the thin films of these alloys in vacuum for different exposure times. The results indicate that photo-crystallization is fast in a-Se95In5 alloy as compared to a-Se95 Te5 alloy. This is explained in terms of lower thermal stability of a-Se95In5 alloy as compared to a-Se95 Te5 alloy.展开更多
Mand-Raigarh coalfield is one of the largest coalfields in the Mahanadi basin. The Geological Survey of India carried out initial study primarily on exploration. However, detailed petrographic and geochemical characte...Mand-Raigarh coalfield is one of the largest coalfields in the Mahanadi basin. The Geological Survey of India carried out initial study primarily on exploration. However, detailed petrographic and geochemical characters of the coals have not been done so far. This investigation is an attempt for petrographic and geochemical appraisal of the coals. Moreover, effort is also made for possible interpretation on development of coal facies. The results drawn from 30 composite coal samples suggest coals are rich in vitrinite, with collotelinite as the dominant maceral while liptinite macerals register low concentration. Dominant mineral assemblages found were clay minerals, pyrite was recorded as disseminated, framboidal and euhedral forms, carbonates recorded were mainly siderites. The vitrinite reflectance random （VRo） mean values range from 0.44 % to 0.56 %, and the rank of coal is suggested as high volatile ＇B＇ to ＇A＇ sub- bituminous in rank. The rock-eval pyrolysis reveal TOC content varying from 37 % to 68.83 %, while low hydrocarbon generating potential is evident from low $2 and Tmax values. The Hydrogen Index （HI） versus Oxygen Index （OI） plot reveal that the samples belong to Kerogen type--II-III with input dominantly from terrestrial source, some samples also fall in Kerogen type--II domain indicating lacustrine input. Vitrinite reflectance result indicate that the samples are immature and approaching oil window, which is in agreement with data of the Rock-Eval parameters. The gelification index （GI） and tissue preservation index （TPI） indicate that the coal developed in a telematic set up with high tree density. The ground water index （GWI） and vegetation index （VI） demonstrate that the peat developed as an ombrogenous bog.展开更多
基金supported by the National Science Foundation through ERC-RMB at NCAT
文摘An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution. The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated. It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples. The corrosion current density for bare magnesium, phytic acid conversion coated magnesium, and post-coating heat treated magnesium was calculated to be 2.48 ×10^-5, 1.18×10^-6, and 9.27 × 10^7 A/cm^2, respectively. The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium. The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.
文摘The fiber reinforced plastics (FRPs) are being used widely in the most diverse applications ranging from the aerospace to the sports goods industry. Drilling in particular is important to facilitate the assembly operations of structurally intricate composite products. The drilling of holes in FRPs leads to drilling induced damage which is an important research area. The researchers worldwide have tried to minimize the damage by optimizing the operating variables, and tool designs as well as by developing unconventional methods of hole making. Most of the work done so far has been experimental in nature with little or no focus on numerical simulation of the drilling behavior of FRPs. In the present research endeavor, a finite element model has been developed to investigate the drilling induced damage of FRP laminates.
文摘We report a comparative study on photo-crystallization in a-Se95 Te5 and a-Se95In5 alloys. The photo-crystallization is achieved by a shining white line on the thin films of these alloys in vacuum for different exposure times. The results indicate that photo-crystallization is fast in a-Se95In5 alloy as compared to a-Se95 Te5 alloy. This is explained in terms of lower thermal stability of a-Se95In5 alloy as compared to a-Se95 Te5 alloy.
文摘Mand-Raigarh coalfield is one of the largest coalfields in the Mahanadi basin. The Geological Survey of India carried out initial study primarily on exploration. However, detailed petrographic and geochemical characters of the coals have not been done so far. This investigation is an attempt for petrographic and geochemical appraisal of the coals. Moreover, effort is also made for possible interpretation on development of coal facies. The results drawn from 30 composite coal samples suggest coals are rich in vitrinite, with collotelinite as the dominant maceral while liptinite macerals register low concentration. Dominant mineral assemblages found were clay minerals, pyrite was recorded as disseminated, framboidal and euhedral forms, carbonates recorded were mainly siderites. The vitrinite reflectance random （VRo） mean values range from 0.44 % to 0.56 %, and the rank of coal is suggested as high volatile ＇B＇ to ＇A＇ sub- bituminous in rank. The rock-eval pyrolysis reveal TOC content varying from 37 % to 68.83 %, while low hydrocarbon generating potential is evident from low $2 and Tmax values. The Hydrogen Index （HI） versus Oxygen Index （OI） plot reveal that the samples belong to Kerogen type--II-III with input dominantly from terrestrial source, some samples also fall in Kerogen type--II domain indicating lacustrine input. Vitrinite reflectance result indicate that the samples are immature and approaching oil window, which is in agreement with data of the Rock-Eval parameters. The gelification index （GI） and tissue preservation index （TPI） indicate that the coal developed in a telematic set up with high tree density. The ground water index （GWI） and vegetation index （VI） demonstrate that the peat developed as an ombrogenous bog.
