The oxidization resistance of the Ni76Cr19A1Ti alloy was studied by a static oxidization experiment at 600-800℃. The results show that the oxidation behavior of the alloy can be explained by a kinetic equation： （△...The oxidization resistance of the Ni76Cr19A1Ti alloy was studied by a static oxidization experiment at 600-800℃. The results show that the oxidation behavior of the alloy can be explained by a kinetic equation： （△m/S）2 = Kpt ＋ C, where Kp is a kinetic constant of the nickel-base alloy. The higher the experimental temperature, the higher the value of Kp. It is discovered that the microstructure of the oxide scales is compact and the thickness of it is less than 10 μm The oxidization of the alloy is in the first grade. It is also found that the oxide scales are mainly composed of Cr2O3 and TiO2. Chrome and titanium react more easily with oxygen at temperatures under the operating mode.展开更多
Advanced fuel economy strategies are expected to reduce the fuel consumption of vehicles.An internal combustion engine(ICE)driving vehicle equipped with free-wheeling turns off the fuel injection and decouples the eng...Advanced fuel economy strategies are expected to reduce the fuel consumption of vehicles.An internal combustion engine(ICE)driving vehicle equipped with free-wheeling turns off the fuel injection and decouples the engine from the drivetrain when the driving force is not required.This paper proposes a method to reduce the fuel consumption of a vehicle equipped with free-wheeling.First,an optimization problem is formulated to minimize the fuel consumption of a vehicle with free-wheeling when the traveling distance,the initial and final speed are specified and the vehicle needs to glide before arriving at the end point for fuel economy.The speed profile of the vehicle,engine operating point,and engine on/off timing are obtained as the results of the optimization.The analytical and numerical analyses results demonstrate the effectiveness and the fuel-saving mechanism of the obtained speed profile.The main finding of the analyses is that rather than starting a gliding stage immediately after an acceleration or a constant speed stage,adding a pre-acceleration stage before the gliding stage is more fuel-economic under some conditions independent of the complexity of the vehicle model.The obtained speed profile including a pre-acceleration stage is applied to a driving scenario including traffic congestions.The results demonstrate the effectiveness of the pre-acceleration stage in reducing fuel consumption for a vehicle equipped with free-wheeling.展开更多
As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to ...As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to the scarcity of kick samples,traditional supervised models perform poorly,and significant fluctuations in field data lead to high false alarm rates.This study proposes an unsupervised graph autoencoder(GAE)-based kick warning method,which effectively reduces false alarms by eliminating the influence of field engineer operations and incorporating real-time model updates.The method utilizes the GAE model to process time-series data during drilling,accurately identifying kick risk while overcoming challenges related to small sample sizes and missing features.To further reduce false alarms,the weighted dynamic time warping(WDTW)algorithm is introduced to identify fluctuations in logging data caused by field engineer operations during drilling,with real-time updates applied to prevent normal conditions from being misclassified as kick risk.Experimental results show that the GAE-based kick warning method achieves an accuracy of 92.7%and significantly reduces the false alarm rate.The GAE model continues to operate effectively even under conditions of missing features and issues kick warnings 4 min earlier than field engineers,demonstrating its high sensitivity and robustness.After integrating the WDTW algorithm and real-time updates,the false alarm rate is reduced from 17.3%to 5.6%,further improving the accuracy of kick warnings.The proposed method provides an efficient and reliable approach for kick warning in drilling operations,offering strong practical value and technical support for the intelligent management of future drilling operations.展开更多
文摘The oxidization resistance of the Ni76Cr19A1Ti alloy was studied by a static oxidization experiment at 600-800℃. The results show that the oxidation behavior of the alloy can be explained by a kinetic equation： （△m/S）2 = Kpt ＋ C, where Kp is a kinetic constant of the nickel-base alloy. The higher the experimental temperature, the higher the value of Kp. It is discovered that the microstructure of the oxide scales is compact and the thickness of it is less than 10 μm The oxidization of the alloy is in the first grade. It is also found that the oxide scales are mainly composed of Cr2O3 and TiO2. Chrome and titanium react more easily with oxygen at temperatures under the operating mode.
文摘Advanced fuel economy strategies are expected to reduce the fuel consumption of vehicles.An internal combustion engine(ICE)driving vehicle equipped with free-wheeling turns off the fuel injection and decouples the engine from the drivetrain when the driving force is not required.This paper proposes a method to reduce the fuel consumption of a vehicle equipped with free-wheeling.First,an optimization problem is formulated to minimize the fuel consumption of a vehicle with free-wheeling when the traveling distance,the initial and final speed are specified and the vehicle needs to glide before arriving at the end point for fuel economy.The speed profile of the vehicle,engine operating point,and engine on/off timing are obtained as the results of the optimization.The analytical and numerical analyses results demonstrate the effectiveness and the fuel-saving mechanism of the obtained speed profile.The main finding of the analyses is that rather than starting a gliding stage immediately after an acceleration or a constant speed stage,adding a pre-acceleration stage before the gliding stage is more fuel-economic under some conditions independent of the complexity of the vehicle model.The obtained speed profile including a pre-acceleration stage is applied to a driving scenario including traffic congestions.The results demonstrate the effectiveness of the pre-acceleration stage in reducing fuel consumption for a vehicle equipped with free-wheeling.
基金Youth Foundation of National Natural Science Foundation of China (No. 52204020)Distinguished Young Foundation of National Natural Science Foundation of China (No. 52125401).
文摘As oil and gas exploration continues to progress into deeper and unconventional reservoirs,the likelihood of kick risk increases,making kick warning a critical factor in ensuring drilling safety and efficiency.Due to the scarcity of kick samples,traditional supervised models perform poorly,and significant fluctuations in field data lead to high false alarm rates.This study proposes an unsupervised graph autoencoder(GAE)-based kick warning method,which effectively reduces false alarms by eliminating the influence of field engineer operations and incorporating real-time model updates.The method utilizes the GAE model to process time-series data during drilling,accurately identifying kick risk while overcoming challenges related to small sample sizes and missing features.To further reduce false alarms,the weighted dynamic time warping(WDTW)algorithm is introduced to identify fluctuations in logging data caused by field engineer operations during drilling,with real-time updates applied to prevent normal conditions from being misclassified as kick risk.Experimental results show that the GAE-based kick warning method achieves an accuracy of 92.7%and significantly reduces the false alarm rate.The GAE model continues to operate effectively even under conditions of missing features and issues kick warnings 4 min earlier than field engineers,demonstrating its high sensitivity and robustness.After integrating the WDTW algorithm and real-time updates,the false alarm rate is reduced from 17.3%to 5.6%,further improving the accuracy of kick warnings.The proposed method provides an efficient and reliable approach for kick warning in drilling operations,offering strong practical value and technical support for the intelligent management of future drilling operations.
