To evaluate the coal burst proneness more precisely,a new energy criterion namely the residual elastic energy index was proposed.This study begins by performing the single-cyclic loading-unloading uniaxial compression...To evaluate the coal burst proneness more precisely,a new energy criterion namely the residual elastic energy index was proposed.This study begins by performing the single-cyclic loading-unloading uniaxial compression tests with five pre-peak unloading stress levels to explore the energy storage characteristics of coal.Five types of coals from different mines were tested,and the instantaneous destruction process of the coal specimens under compression loading was recorded using a high speed camera.The results showed a linear relationship between the elastic strain energy density and input energy density,which confirms the linear energy storage law of coal.Based on this linear energy storage law,the peak elastic strain energy density of each coal specimen was obtained precisely.Subsequently,a new energy criterion of coal burst proneness was established,which was called the residual elastic energy index(defined as the difference between the peak elastic strain energy density and post peak failure energy density).Considering the destruction process and actual failure characteristics of coal specimens,the accuracy of evaluating coal burst proneness based on the residual elastic energy index was examined.The results indicated that the residual elastic energy index enables reliable and precise evaluations of the coal burst proneness.展开更多
Based on the mechanical experiment of brittle coal-rock and the damage mechanical theory, a damage model was established. Coal-Rock damage mechanical characteristic was researched. Furthermore, interior energy transfo...Based on the mechanical experiment of brittle coal-rock and the damage mechanical theory, a damage model was established. Coal-Rock damage mechanical characteristic was researched. Furthermore, interior energy transformation mechanism of rock was analyzed from the point of view of damage mechanics and damage energy release rate of brittle coal rock was derived. By analyzing the energy transformation of rock burst, a new conception, damage energy index of rock burst, was put forward. The condition of rock burst was also established.展开更多
This paper describes the characteristics of liquefied natural gas （LNG） carriers briefly. The LNG carrier includes power plant selection, vapor treatment, liquid cargo tank type, etc. Two parameters fuel substitutio...This paper describes the characteristics of liquefied natural gas （LNG） carriers briefly. The LNG carrier includes power plant selection, vapor treatment, liquid cargo tank type, etc. Two parameters fuel substitution rate and recovery of boil of gas （BOG） volume to energy efficiency design index （EEDI） formula are added, and EEDI formula of LNG carriers is established based on ship EEDI formula. Then, based on steam turbine propulsion device of LNG carriers, mathematical models of LNG carriers＇ reference line value are established in this paper. By verification, the EEDI formula of LNG carriers described in this paper can provide a reference for LNG carrier EEDI calculation and green shipbuilding.展开更多
Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization （around 40%） and low availability （around 60%）. The main purpose of this study is to develop a drill selec- t...Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization （around 40%） and low availability （around 60%）. The main purpose of this study is to develop a drill selec- tion methodology and simultaneously a performance evaluation technique based on drill cuttings produced and drilling rate achieved. In all 28 blast drilled through were investigated. The drilling was accomplished by 5 different drill machines of Ingersoll-Rand and Revathi working in coal mines of Sonepur Bazari （SECL） and Block-II （BCCL）. The drills are Rotary and Rotary Percussive type using tri- cone rock roller bits. Drill cuttings were collected and sieve analysis was done in the laboratory. Using Rosin Ramler Diagram, coarseness index （CI）, mean chip size （d）, specific-st trace area （SSA） and charac- teristic particle size distribution curves for all the holes drilled were plotted. The predictor equation for drill penetration rate established through multiple regressions was found to have a very good correlation with an index of determination of 0.85. A comparative analysis of particle size distribution curves was used to evaluate the drill efficiency. The suggested approach utilises the area under the curve, after the point of trend reversal and brittleness ratio of the respective bench to arrive at drill energy utilization index （DEUI）, for mapping of drill machine to bench, The developed DEU1 can aid in selecting or mapping a right machine to right bench for achieving higher penetration rate and utilizations.展开更多
More than 10000 different types of ship ply the waters of Bangladesh all year round,but the performance of these ships in terms of CO2 emission is not known and regulations related to energy efficiency of inland water...More than 10000 different types of ship ply the waters of Bangladesh all year round,but the performance of these ships in terms of CO2 emission is not known and regulations related to energy efficiency of inland waterway ships remain nonexistent.This paper attempts to assess the present situation of inland class vessels in terms of Energy Efficiency Design Index(EEDI).With the use of a developed database of inland vessels in Bangladesh,EEDI reference lines for different types of inland vessels in Bangladesh were established and then compared with those of other countries.The present EEDI of existing inland vessels was investigated.Results indicate that most of the existing vessels do not meet the current EEDI baseline.Hence,new guidelines are necessary to achieve EEDI compliance in the near future.Some recommendations were proposed for improving CO2 emissions,with the socioeconomic and technical factors in Bangladesh taken into consideration.展开更多
To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes....To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes.The tests involved loading the samples to 60%,70%,and 80%of their uniaxial compressive strength,followed by unloading and reloading until failure.Key parameters such as the elastic energy index and linear elasticity criteria were derived from these tests.Additionally,rock fragments were collected to calculate their initial ejection kinetic energy,serving as a measure of rockburst tendency.The classification of rockburst tendency was conducted using grading methods based on burst energy index(WET),pre-peak stored elastic energy(PES)and experimental observations.Multi-class classification and regression analyses were applied to machine learning models using experimental data to predict rockburst tendency levels.A comparative analysis of models from two libraries revealed that the Random Forest model achieved the highest accuracy in classification,while the Ada Boost Regressor model excelled in regression predictions.This study highlights that on a laboratory scale,integrating ejection kinetic energy with the unloading ratio,failure load,W_(ET)and PES through machine learning offers a highly accurate and reliable approach for determining rockburst tendency levels.展开更多
Green Internet of things （loT） has been heralded as the ＂next big thing＂ waiting to be realized in energy-efficient ubiquitous computing. Green IoT revolves around increased machine-to-machine communications and e...Green Internet of things （loT） has been heralded as the ＂next big thing＂ waiting to be realized in energy-efficient ubiquitous computing. Green IoT revolves around increased machine-to-machine communications and encompasses energy-efficient wireless embedded sensors and actuators that assist in monitoring and controlling home appliances. Energy efficiency in home applications can be achieved by better monitoring of the specific energy consumption by the appliances. There are many wireless standards that can be adopted for the design of such embedded devices in loT. These communication technologies cater to different requirements and are classified as the short-range and long-range ones. To select the best communication method, this paper surveys various loT communication technologies and discusses the advantages and disadvantages to develop an energy monitoring system. An IoT device based on the Wi-Fi technology system is developed and tested for usage in the home energy monitoring environment. The performance of this system is then evaluated by the measurement of power consumption metrics. In the efficient deep-sleep mode, the system saves up to 0.3 W per cycle with an average power dissipation of less than 0.1 W/s.展开更多
Climate change and global warming are among the most severe threats to the global ecosystem,caused by greenhouse gas emissions.Therefore,all industries that cause environmental emissions should collaborate in the stru...Climate change and global warming are among the most severe threats to the global ecosystem,caused by greenhouse gas emissions.Therefore,all industries that cause environmental emissions should collaborate in the struggle against climate change.In this context,the International Maritime Organization(IMO)approved the initial greenhouse gas strategy at the MEPC 72 session in April 2018 to achieve targets for 2050.With this strategy,the IMO aims to create and improve new regulations that can enhance energy efficiency to achieve their short-term,midterm,and long-term goals.In this study,one of the novel terms,energy efficiency existing ship index(EEXI)values,has been calculated for the Turkish fleet to guide the maritime sector.The Turkish fleet in the study refers to the Turkish-owned vessels both sailing with a national or international flag.In accordance with this regulation,the number of Turkish fleets that were identified as either above or below the IMO reference lines has been determined.Additionally,EEXI values have been recalculated using the engine power limitation(EPL)method for ships that exceed the required limits,and the success rate of this method has been estimated.As a result,the application of EPL increased the number of ships below the Phase 2 reference line from 15.6%to 53.1%.To the best of our knowledge,this research,which has been carried out on all Turkish-owned ships,is the first study intended to serve as a guide for other ship owners in the global maritime industry regarding energy efficiency management.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.41877272)the Fundamental Research Funds for the Central Universities of Southeast University(No.2242021R10080).
文摘To evaluate the coal burst proneness more precisely,a new energy criterion namely the residual elastic energy index was proposed.This study begins by performing the single-cyclic loading-unloading uniaxial compression tests with five pre-peak unloading stress levels to explore the energy storage characteristics of coal.Five types of coals from different mines were tested,and the instantaneous destruction process of the coal specimens under compression loading was recorded using a high speed camera.The results showed a linear relationship between the elastic strain energy density and input energy density,which confirms the linear energy storage law of coal.Based on this linear energy storage law,the peak elastic strain energy density of each coal specimen was obtained precisely.Subsequently,a new energy criterion of coal burst proneness was established,which was called the residual elastic energy index(defined as the difference between the peak elastic strain energy density and post peak failure energy density).Considering the destruction process and actual failure characteristics of coal specimens,the accuracy of evaluating coal burst proneness based on the residual elastic energy index was examined.The results indicated that the residual elastic energy index enables reliable and precise evaluations of the coal burst proneness.
基金Doctoral fund of ministry of education,China(2 0 0 0 0 61115 ) the teaching and research award program for outstandingyoung teachers in higher education institutions of MOE,P.R.C.,(TRAPOYT)
文摘Based on the mechanical experiment of brittle coal-rock and the damage mechanical theory, a damage model was established. Coal-Rock damage mechanical characteristic was researched. Furthermore, interior energy transformation mechanism of rock was analyzed from the point of view of damage mechanics and damage energy release rate of brittle coal rock was derived. By analyzing the energy transformation of rock burst, a new conception, damage energy index of rock burst, was put forward. The condition of rock burst was also established.
基金Foundation item： Supported by the National Special Fund for Agro-scientific Research in the Public Interest （No.201003024）, and the National Natural Science Foundation of China （No.51409042 No. 51209034）.
文摘This paper describes the characteristics of liquefied natural gas （LNG） carriers briefly. The LNG carrier includes power plant selection, vapor treatment, liquid cargo tank type, etc. Two parameters fuel substitution rate and recovery of boil of gas （BOG） volume to energy efficiency design index （EEDI） formula are added, and EEDI formula of LNG carriers is established based on ship EEDI formula. Then, based on steam turbine propulsion device of LNG carriers, mathematical models of LNG carriers＇ reference line value are established in this paper. By verification, the EEDI formula of LNG carriers described in this paper can provide a reference for LNG carrier EEDI calculation and green shipbuilding.
文摘Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization （around 40%） and low availability （around 60%）. The main purpose of this study is to develop a drill selec- tion methodology and simultaneously a performance evaluation technique based on drill cuttings produced and drilling rate achieved. In all 28 blast drilled through were investigated. The drilling was accomplished by 5 different drill machines of Ingersoll-Rand and Revathi working in coal mines of Sonepur Bazari （SECL） and Block-II （BCCL）. The drills are Rotary and Rotary Percussive type using tri- cone rock roller bits. Drill cuttings were collected and sieve analysis was done in the laboratory. Using Rosin Ramler Diagram, coarseness index （CI）, mean chip size （d）, specific-st trace area （SSA） and charac- teristic particle size distribution curves for all the holes drilled were plotted. The predictor equation for drill penetration rate established through multiple regressions was found to have a very good correlation with an index of determination of 0.85. A comparative analysis of particle size distribution curves was used to evaluate the drill efficiency. The suggested approach utilises the area under the curve, after the point of trend reversal and brittleness ratio of the respective bench to arrive at drill energy utilization index （DEUI）, for mapping of drill machine to bench, The developed DEU1 can aid in selecting or mapping a right machine to right bench for achieving higher penetration rate and utilizations.
文摘More than 10000 different types of ship ply the waters of Bangladesh all year round,but the performance of these ships in terms of CO2 emission is not known and regulations related to energy efficiency of inland waterway ships remain nonexistent.This paper attempts to assess the present situation of inland class vessels in terms of Energy Efficiency Design Index(EEDI).With the use of a developed database of inland vessels in Bangladesh,EEDI reference lines for different types of inland vessels in Bangladesh were established and then compared with those of other countries.The present EEDI of existing inland vessels was investigated.Results indicate that most of the existing vessels do not meet the current EEDI baseline.Hence,new guidelines are necessary to achieve EEDI compliance in the near future.Some recommendations were proposed for improving CO2 emissions,with the socioeconomic and technical factors in Bangladesh taken into consideration.
基金financial support for this work provided by the National Natural Science Foundation of China (No.52227901)。
文摘To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes.The tests involved loading the samples to 60%,70%,and 80%of their uniaxial compressive strength,followed by unloading and reloading until failure.Key parameters such as the elastic energy index and linear elasticity criteria were derived from these tests.Additionally,rock fragments were collected to calculate their initial ejection kinetic energy,serving as a measure of rockburst tendency.The classification of rockburst tendency was conducted using grading methods based on burst energy index(WET),pre-peak stored elastic energy(PES)and experimental observations.Multi-class classification and regression analyses were applied to machine learning models using experimental data to predict rockburst tendency levels.A comparative analysis of models from two libraries revealed that the Random Forest model achieved the highest accuracy in classification,while the Ada Boost Regressor model excelled in regression predictions.This study highlights that on a laboratory scale,integrating ejection kinetic energy with the unloading ratio,failure load,W_(ET)and PES through machine learning offers a highly accurate and reliable approach for determining rockburst tendency levels.
文摘Green Internet of things （loT） has been heralded as the ＂next big thing＂ waiting to be realized in energy-efficient ubiquitous computing. Green IoT revolves around increased machine-to-machine communications and encompasses energy-efficient wireless embedded sensors and actuators that assist in monitoring and controlling home appliances. Energy efficiency in home applications can be achieved by better monitoring of the specific energy consumption by the appliances. There are many wireless standards that can be adopted for the design of such embedded devices in loT. These communication technologies cater to different requirements and are classified as the short-range and long-range ones. To select the best communication method, this paper surveys various loT communication technologies and discusses the advantages and disadvantages to develop an energy monitoring system. An IoT device based on the Wi-Fi technology system is developed and tested for usage in the home energy monitoring environment. The performance of this system is then evaluated by the measurement of power consumption metrics. In the efficient deep-sleep mode, the system saves up to 0.3 W per cycle with an average power dissipation of less than 0.1 W/s.
基金Supported by Yildiz Technical University(YTU)Scientific Research Project Coordination Unit(SRPC)(BAPK)(Grant No.FBA-2021-4470).
文摘Climate change and global warming are among the most severe threats to the global ecosystem,caused by greenhouse gas emissions.Therefore,all industries that cause environmental emissions should collaborate in the struggle against climate change.In this context,the International Maritime Organization(IMO)approved the initial greenhouse gas strategy at the MEPC 72 session in April 2018 to achieve targets for 2050.With this strategy,the IMO aims to create and improve new regulations that can enhance energy efficiency to achieve their short-term,midterm,and long-term goals.In this study,one of the novel terms,energy efficiency existing ship index(EEXI)values,has been calculated for the Turkish fleet to guide the maritime sector.The Turkish fleet in the study refers to the Turkish-owned vessels both sailing with a national or international flag.In accordance with this regulation,the number of Turkish fleets that were identified as either above or below the IMO reference lines has been determined.Additionally,EEXI values have been recalculated using the engine power limitation(EPL)method for ships that exceed the required limits,and the success rate of this method has been estimated.As a result,the application of EPL increased the number of ships below the Phase 2 reference line from 15.6%to 53.1%.To the best of our knowledge,this research,which has been carried out on all Turkish-owned ships,is the first study intended to serve as a guide for other ship owners in the global maritime industry regarding energy efficiency management.
