Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was stud...Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was studied.Prior pyrolysis affects the initial temperature of mass loss and the ignition temperature.The ignition temperature increases as the volatile content of the sample decreases.TG/DTG curves obtained at different heating rates show that heating rate has little effect on ignition temperature.But the peak of combustion shifts to higher temperatures as the heating rate is increased.The Coats-Redfern integration method was employed to find the combustion-reaction kinetic parameters for the burning of oil shale and oil shale semi-coke.展开更多
Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional upli...Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional uplifts and erosion of the tectonic units. This study focuses on utilizing drainage network extracted from Shuttle Radar Digital Elevation Data （SRTM-DEM） in order to constrain the structure of the Potwar Plateau. SWAN syncline divides Potwar into northern Potwar deformed zone （NPDZ） and southern Potwar platform zone （SPPZ）. We extracted the drainage network from DEM and analyzed 112 streams using stream power law. Spatial distribution of concavity and steepness indices were used to prepare uplift rate map for the area. DEM was further utilized to extract lineaments to study the mutual relationship between lineaments and drainage patterns. We compared the local correlation between the extracted lineaments and drainage network of the area that gives us quantitative information and shows promising prospects. The streams in the NPDZ indicate high steepness values as compared to the streams in the SPPZ. The spatial distribution of geomorphic parameters distinctive deformation and uplift rates suggest the among eastern, central and western parts. The local correlation between drainage network and lineaments from DEM is strongly positive in the area within I km of radius.展开更多
The primary objective of present investigation is to introduce the novel aspects of convective mass condition and thermal radiation in the peristaltic transport of fluid. Magnetohydrodynamic(MHD) fluid was considered ...The primary objective of present investigation is to introduce the novel aspects of convective mass condition and thermal radiation in the peristaltic transport of fluid. Magnetohydrodynamic(MHD) fluid was considered in a symmetric channel. Heat and mass transfer characteristics were analyzed in the presence of Soret and Dufour effects, and the results were presented via two forms of thermal radiation. The temperature, concentration and pressure rise per wavelength were examined. It is observed that the velocity slip and magnetic field parameters have opposite effects on the pressure rise per wavelength. Temperature of fluid is a decreasing function of the radiation parameter. Further, the temperature of fluid decreases by increasing the heat transfer Biot number. It is notified that the heat transfer rate at the wall is a decreasing function of radiation parameter.展开更多
Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of ...Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of this sector. However, due to global nature and the long term sustainability of this shipbuilding industry, an investigation of competitiveness in terms of global standard is of prime importance. This paper focuses on studying some crucial competitive factors like labor skill, labor availability, labor man-hour, labor cost ＆ productivity for local shipbuilding in Bangladesh. The analysis also focuses on existing access to the resources like materials, knowledge and capital which are equally important factors for the expansion of shipbuilding. Comparison of these parameters with other nations have been made qualitatively and quantitatively to find the level of our shipbuilding. On the basis of existing condition and future vision, some recommendations have been made which might be useful for accelerating the development of this sector.展开更多
The iso-conversion method to could calculate the kinetics parameters effectively, the present paper built an evaluation equation for iso-conversion methods according to the thermo kinetics integral equation and analys...The iso-conversion method to could calculate the kinetics parameters effectively, the present paper built an evaluation equation for iso-conversion methods according to the thermo kinetics integral equation and analyses the temperatures of the same degree of conversion for different heating rates by ideal TG （thermo-gravity） curve data. It is obtained that the temperatures of the same degree of conversion for different heating rates＇ TG curve have good linearity connection validating the correction of the evaluation equation for iso-conversion methods and the scope of linear slope for theratio between heating rates being 2 is 1.05 to 1.09.展开更多
Multi-converter approach based on the series and parallel connection topology of modular power converters has been proposed to realize higher power density DC-DC converter. The availability of the proposed approach ha...Multi-converter approach based on the series and parallel connection topology of modular power converters has been proposed to realize higher power density DC-DC converter. The availability of the proposed approach has been verified through the design consideration and the experiment. The design consideration for two DC-DC converters has been carried out by utilizing the power converter exact loss simulator, and the design parameters to maximize their power densities have been extracted taking the trade-off between the conversion efficiency and the power density into account. The prototypes of a 2,400 W, 256-384 V boost chopper using SiC-MOSFETs and a 300 W, 32-48 V GaN-FETs boost chopper have been also developed based on the design. The SiC chopper achieved the efficiency of 97.8% and the power density of 12,8 W/cm3, and the GaN chopper accomplished 98.9% and 18.6 W/cm3 in the experiment. These results show the validity of the design and the availability of the proposed approach. The multi-converter approach enables the cost reduction of the modular power converters, and contributes to realizing the widespread use of power electronics converters in the future 380 V DC distribution system.展开更多
基金Project CPEUKF08-04 support by the Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education of China
文摘Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was studied.Prior pyrolysis affects the initial temperature of mass loss and the ignition temperature.The ignition temperature increases as the volatile content of the sample decreases.TG/DTG curves obtained at different heating rates show that heating rate has little effect on ignition temperature.But the peak of combustion shifts to higher temperatures as the heating rate is increased.The Coats-Redfern integration method was employed to find the combustion-reaction kinetic parameters for the burning of oil shale and oil shale semi-coke.
文摘Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional uplifts and erosion of the tectonic units. This study focuses on utilizing drainage network extracted from Shuttle Radar Digital Elevation Data （SRTM-DEM） in order to constrain the structure of the Potwar Plateau. SWAN syncline divides Potwar into northern Potwar deformed zone （NPDZ） and southern Potwar platform zone （SPPZ）. We extracted the drainage network from DEM and analyzed 112 streams using stream power law. Spatial distribution of concavity and steepness indices were used to prepare uplift rate map for the area. DEM was further utilized to extract lineaments to study the mutual relationship between lineaments and drainage patterns. We compared the local correlation between the extracted lineaments and drainage network of the area that gives us quantitative information and shows promising prospects. The streams in the NPDZ indicate high steepness values as compared to the streams in the SPPZ. The spatial distribution of geomorphic parameters distinctive deformation and uplift rates suggest the among eastern, central and western parts. The local correlation between drainage network and lineaments from DEM is strongly positive in the area within I km of radius.
文摘The primary objective of present investigation is to introduce the novel aspects of convective mass condition and thermal radiation in the peristaltic transport of fluid. Magnetohydrodynamic(MHD) fluid was considered in a symmetric channel. Heat and mass transfer characteristics were analyzed in the presence of Soret and Dufour effects, and the results were presented via two forms of thermal radiation. The temperature, concentration and pressure rise per wavelength were examined. It is observed that the velocity slip and magnetic field parameters have opposite effects on the pressure rise per wavelength. Temperature of fluid is a decreasing function of the radiation parameter. Further, the temperature of fluid decreases by increasing the heat transfer Biot number. It is notified that the heat transfer rate at the wall is a decreasing function of radiation parameter.
文摘Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of this sector. However, due to global nature and the long term sustainability of this shipbuilding industry, an investigation of competitiveness in terms of global standard is of prime importance. This paper focuses on studying some crucial competitive factors like labor skill, labor availability, labor man-hour, labor cost ＆ productivity for local shipbuilding in Bangladesh. The analysis also focuses on existing access to the resources like materials, knowledge and capital which are equally important factors for the expansion of shipbuilding. Comparison of these parameters with other nations have been made qualitatively and quantitatively to find the level of our shipbuilding. On the basis of existing condition and future vision, some recommendations have been made which might be useful for accelerating the development of this sector.
文摘The iso-conversion method to could calculate the kinetics parameters effectively, the present paper built an evaluation equation for iso-conversion methods according to the thermo kinetics integral equation and analyses the temperatures of the same degree of conversion for different heating rates by ideal TG （thermo-gravity） curve data. It is obtained that the temperatures of the same degree of conversion for different heating rates＇ TG curve have good linearity connection validating the correction of the evaluation equation for iso-conversion methods and the scope of linear slope for theratio between heating rates being 2 is 1.05 to 1.09.
文摘Multi-converter approach based on the series and parallel connection topology of modular power converters has been proposed to realize higher power density DC-DC converter. The availability of the proposed approach has been verified through the design consideration and the experiment. The design consideration for two DC-DC converters has been carried out by utilizing the power converter exact loss simulator, and the design parameters to maximize their power densities have been extracted taking the trade-off between the conversion efficiency and the power density into account. The prototypes of a 2,400 W, 256-384 V boost chopper using SiC-MOSFETs and a 300 W, 32-48 V GaN-FETs boost chopper have been also developed based on the design. The SiC chopper achieved the efficiency of 97.8% and the power density of 12,8 W/cm3, and the GaN chopper accomplished 98.9% and 18.6 W/cm3 in the experiment. These results show the validity of the design and the availability of the proposed approach. The multi-converter approach enables the cost reduction of the modular power converters, and contributes to realizing the widespread use of power electronics converters in the future 380 V DC distribution system.
