Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refi...Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.展开更多
It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results co...It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results confirmed that lead-time was decreased and product customization was improved in making die by using computer technology. At the same time, precision molding can decrease the reject ratio of refiner plates, and optimizing the alloy and shakeout time can eliminate the need for heat treatment. The new fabricating process showed several advantages over the traditional process in increasing toughness, better casting precision, elimination of the annealing treatment stage and raising production efficiency.展开更多
Currently ＂The Crude Formulation Technique＂ developed by the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical review sponsored by the Sinopec Corp.This technique by means of adopti...Currently ＂The Crude Formulation Technique＂ developed by the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical review sponsored by the Sinopec Corp.This technique by means of adopting the advanced algorithm on the basis of the crude assay data bank and the large crude spectroscopic database can intelligently blend together different kinds of crude oils to obtain multiple crude formulations, the quality of which is quite close to the target crude in a bid to provide technical support to the refining enterprises in the area of crude procurement and sustained property stabilization of crude oils pro-cessed thereby.展开更多
Analysts say an independent oil refiners’alliance in Shandong will help the teapot refiners enhance bargaining power and reduce vicious competition amidan excess capacity in the sector.Several teapots in Shandong hav...Analysts say an independent oil refiners’alliance in Shandong will help the teapot refiners enhance bargaining power and reduce vicious competition amidan excess capacity in the sector.Several teapots in Shandong have set up a refining conglomerate recently with a planned registered capital reaching 90 billion yuan($13.67 billion).This will combine the country’s largest independent oil refineries,known as teapots。展开更多
This article sums up the energy consumption of process units and the overall energy consumption of 10 Mt/a class refineries constructed or revamped in recent years. The energy saving measures adopted in design of thes...This article sums up the energy consumption of process units and the overall energy consumption of 10 Mt/a class refineries constructed or revamped in recent years. The energy saving measures adopted in design of these refineries are analyzed and discussed. Finally, this article also makes comments and puts forward recommendations on the objectives for energy conservation at refineries in the future.展开更多
Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better ref...Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better reflect the real supply-demand situation.For the first time,this paper applies own-monitored dailyfrequency wholesale prices of China’s private enterprises and local refineries during 2013-2020 to derive spillover effects of international crude oil prices on China’s refined oil prices through the VAR-BEKKGARCH(vector autoregression-Baba,Engle,Kraft,and Kroner-generalized autoregressive conditional heteroscedasticity)model,and then tries to forecast wholesale prices through the PCA-BP(principal component analysis-back propagation)neural network model.Results show that international crude oil prices have significant mean spillover and volatility spillover effects on China’s refined oil wholesale prices.Changes in crude oil prices are the Granger cause of changes in refined oil wholesale prices.With the improvement of China’s oil-pricing mechanism in 2016,the volatility spillover from the international crude oil market to China’s refined oil market gradually increases,and the BRENT price variation has an increasing impact on the refined oil wholesale price variation.The PCA-BP model could serve as a candidate tool for forecasting China’s refined oil wholesale prices.展开更多
The paper reviewed the refining and marketing business of both domestic and international oil companies, and tried to figure out the gap of domestic refining enterprises in terms of the refinery scale, processing unil...The paper reviewed the refining and marketing business of both domestic and international oil companies, and tried to figure out the gap of domestic refining enterprises in terms of the refinery scale, processing unil configuration, stream factor and competitive edge as compared to overseas refineries. The paper also concluded that the net margin of domestic refineries is about $ 1.0/bbl lower than that of the overseas refineries, and proposed some ideas to sharpen the competitive edge of Chinese refining industry.展开更多
In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent mo...In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.展开更多
An analytical method for analyzing the thermal vibration of multi-directional functionally graded porous rectangular plates in fluid media with novel porosity patterns is developed in this study.Mechanical properties ...An analytical method for analyzing the thermal vibration of multi-directional functionally graded porous rectangular plates in fluid media with novel porosity patterns is developed in this study.Mechanical properties of MFG porous plates change according to the length,width,and thickness directions for various materials and the porosity distribution which can be widely applied in many fields of engineering and defence technology.Especially,new porous rules that depend on spatial coordinates and grading indexes are proposed in the present work.Applying Hamilton's principle and the refined higher-order shear deformation plate theory,the governing equation of motion of an MFG porous rectangular plate in a fluid medium(the fluid-plate system)is obtained.The fluid velocity potential is derived from the boundary conditions of the fluid-plate system and is used to compute the extra mass.The GalerkinVlasov solution is used to solve and give natural frequencies of MFG porous plates with various boundary conditions in a fluid medium.The validity and reliability of the suggested method are confirmed by comparing numerical results of the present work with those from available works in the literature.The effects of different parameters on the thermal vibration response of MFG porous rectangular plates are studied in detail.These findings demonstrate that the behavior of the structure within a liquid medium differs significantly from that within a vacuum medium.Thereby,they offer appropriate operational approaches for the structure when employed in various mediums.展开更多
A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface i...A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.展开更多
This study explores the utilization of various chemometric analytical methods for determining the quality of pressed sesame oil with different adulteration levels of refined sesame oil using UV spectral fingerprints.T...This study explores the utilization of various chemometric analytical methods for determining the quality of pressed sesame oil with different adulteration levels of refined sesame oil using UV spectral fingerprints.The goal of this study was to provide a reliable tool for assessing the quality of sesame oil.The UV spectra of 51 samples of pressed sesame oil and 420 adulterated samples with refined sesame oil were measured in the range of 200-330 nm.Various classification and prediction methods,including linear discrimination analysis(LDA),support vector machines(SVM),soft independent modeling of class analogy(SIMCA),partial least squares regression(PLSR),support vector machine regression(SVR),and back-propagation neural network(BPNN),were employed to analyze the UV spectral data of pressed sesame oil and adulterated sesame oil.The results indicated that SVM outperformed the other classification methods in qualitatively identifying adulterated sesame oil,achieving an accuracy of 96.15%,a sensitivity of 97.87%,and a specificity of 80%.For quantitative analysis,BPNN yielded the best prediction results,with an R^(2) value of 0.99,RMSEP of 2.34%,and RPD value of 10.60(LOD of 8.60%and LOQ of 28.67%).Overall,the developed models exhibited significant potential for rapidly identifying and predicting the quality of sesame oil.展开更多
In this article,we first establish an asymptotically sharp result on the higher order Fréchet derivatives for bounded holomorphic mappings f(x)=f(0)+∞∑s=1Dskf(0)(x^(sk))/(sk)!:B_(X)→B_(Y),where B_X is the unit...In this article,we first establish an asymptotically sharp result on the higher order Fréchet derivatives for bounded holomorphic mappings f(x)=f(0)+∞∑s=1Dskf(0)(x^(sk))/(sk)!:B_(X)→B_(Y),where B_X is the unit ball of X.We next give a sharp result on the first order Fréchet derivative for bounded holomorphic mappings F(X)=F(0+)∞∑s=KD^(s)f(0)(x^(8)/s!):B_(X)→B_(Y),where B_(X)is the unit ball of X.The results that we derive include some results in several complex variables,and extend the classical result in one complex variable to several complex variables.展开更多
Over the past decade,China’s refined oil market has experienced considerable growth and fluctuations.Gasoline consumption has generally followed the growth rate of vehicle equipment,with fluctuations influenced by tr...Over the past decade,China’s refined oil market has experienced considerable growth and fluctuations.Gasoline consumption has generally followed the growth rate of vehicle equipment,with fluctuations influenced by travel frequency;aviation fuel consumption has seen stable growth following the end of COVID-19,while diesel consumption has been affected by multiple factors including demand and policy.With the rapid development of new energy vehicles and alternative fuels,the gasoline and diesel market has essentially peaked,yet domestic production of refined oil continues to grow,leading to an increasingly prominent oversupply issue.To achieve the dual carbon goals,the Chinese government has introduced a series of policies that have a profound impact on the refined oil market.Facing resource surplus and market demand changes,the refining industry needs to optimize production capacity structure,and oil products retail companies face transformation pressure.The article aims to provide market analysis and recommendations,serving as a reference for relevant enterprises and policymakers.展开更多
The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in...The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
A complete mesh free adaptive algorithm （MFAA）, with solution adaptation and geometric adaptation, is developed to improve the resolution of flow features and to replace traditional global refinement techniques in s...A complete mesh free adaptive algorithm （MFAA）, with solution adaptation and geometric adaptation, is developed to improve the resolution of flow features and to replace traditional global refinement techniques in structured grids. Unnecessary redundant points and elements are avoided by using the mesh free local clouds refinement technology in shock influencing regions and regions near large curvature places on the boundary. Inviscid compressible flows over NACA0012 and RAE2822 airfoils are computed. Finally numerical results validate the accuracy of the above method.展开更多
Vacuum sintering and ball milling methods were employed in the preparation process of Ti-C grain refine- ment and the ability of refiners with varying ratios of Ti and C to refine ZL111 crystal grains was tested. The ...Vacuum sintering and ball milling methods were employed in the preparation process of Ti-C grain refine- ment and the ability of refiners with varying ratios of Ti and C to refine ZL111 crystal grains was tested. The refinement effect of the Ti-C ratios on tensile strength, elongation percentage, Brinell hardness, pro-eutectoid αAl and the size of the Si phase of ZL111, after modification by rare-earth and strontium nitrate, were studied by means of metallographic examination, SEM and mechanical property tests. The results show that there is an obvious increase in the tensile strength and elongation percentage of refined ZL111 with these new Ti and C refiner compounding powders, while Brinell hardness remained more or less constant. The pro-eutectoid αAl is considerably reduced in size and the Si phase shows a finer and rounder structure. The refiner exhibits a good grain refining performance when the Ti-C ratio is 25:1, for Al crystals can favorably easily form nuclei and grow up along the TiC surface thanks to the TiAl3 generated by sur- plus Ti and Al. The mechanical properties have clearly been improved by the addition of strontium nitrate to ZL111. The effective factors in the modification of mechanical properties of ZL111 are in order of importance: strontium nitrate, Ti-C ratio and rare earth.展开更多
The oil refining and petrochemical industry in China has made great achievements after decades of development, and its capacity has already ranked second in the world. However, the refining industry is suffering some ...The oil refining and petrochemical industry in China has made great achievements after decades of development, and its capacity has already ranked second in the world. However, the refining industry is suffering some challenges, such as severe overcapacity at present, and has entered a new economic normal, in which the technological progress develops rapidly, the demand for green and low-carbon development is stricter, the market competition is increasingly fiercer and the profit margins are gradually narrowing. In such a situation, informatization and its new technologies are driving the significant reforming of manufacturing patterns, marketing patterns, management and decision-making patterns. Intelligent development is the inevitable choice for the transformation and upgrading of oil refining and petrochemical industry. It is suggested that the intelligent evaluating model and method should be adopted to enterprise’s intelligentializing transformation and upgrading by laying a solid foundation of digital refinery and implemenation of digital upgrading.展开更多
Based upon a generalized variational principle, which relaxed the inter element continuity requirements, a novel refined hybrid Mindlin plate element is developed, its non linear element stiffness matrices are decom...Based upon a generalized variational principle, which relaxed the inter element continuity requirements, a novel refined hybrid Mindlin plate element is developed, its non linear element stiffness matrices are decomposed into a series of matrices with respect to the assumed strain modes. The formulation presented in this paper is different from any other non linear mixed/hybrid element formulation all successful experience of linear hybrid formulation is absorbed into the formulation(adding non conforming modes and realizing orthogonalization) Numerical results show that the present approach is more effective than any other non linear hybrid element formulation over the accuracy and computational efficiency. In addition, non conforming modes can also overcome the shear locking effect.展开更多
文摘Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.
文摘It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results confirmed that lead-time was decreased and product customization was improved in making die by using computer technology. At the same time, precision molding can decrease the reject ratio of refiner plates, and optimizing the alloy and shakeout time can eliminate the need for heat treatment. The new fabricating process showed several advantages over the traditional process in increasing toughness, better casting precision, elimination of the annealing treatment stage and raising production efficiency.
文摘Currently ＂The Crude Formulation Technique＂ developed by the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical review sponsored by the Sinopec Corp.This technique by means of adopting the advanced algorithm on the basis of the crude assay data bank and the large crude spectroscopic database can intelligently blend together different kinds of crude oils to obtain multiple crude formulations, the quality of which is quite close to the target crude in a bid to provide technical support to the refining enterprises in the area of crude procurement and sustained property stabilization of crude oils pro-cessed thereby.
文摘Analysts say an independent oil refiners’alliance in Shandong will help the teapot refiners enhance bargaining power and reduce vicious competition amidan excess capacity in the sector.Several teapots in Shandong have set up a refining conglomerate recently with a planned registered capital reaching 90 billion yuan($13.67 billion).This will combine the country’s largest independent oil refineries,known as teapots。
文摘This article sums up the energy consumption of process units and the overall energy consumption of 10 Mt/a class refineries constructed or revamped in recent years. The energy saving measures adopted in design of these refineries are analyzed and discussed. Finally, this article also makes comments and puts forward recommendations on the objectives for energy conservation at refineries in the future.
基金the financial support from the Science Foundation of China University of Petroleum,Beijing(2462020YXZZ038)
文摘Compared with retail prices of state-owned companies used in almost all existing studies,China’s refined oil wholesale prices of private enterprises and local refineries are more affected by the market and better reflect the real supply-demand situation.For the first time,this paper applies own-monitored dailyfrequency wholesale prices of China’s private enterprises and local refineries during 2013-2020 to derive spillover effects of international crude oil prices on China’s refined oil prices through the VAR-BEKKGARCH(vector autoregression-Baba,Engle,Kraft,and Kroner-generalized autoregressive conditional heteroscedasticity)model,and then tries to forecast wholesale prices through the PCA-BP(principal component analysis-back propagation)neural network model.Results show that international crude oil prices have significant mean spillover and volatility spillover effects on China’s refined oil wholesale prices.Changes in crude oil prices are the Granger cause of changes in refined oil wholesale prices.With the improvement of China’s oil-pricing mechanism in 2016,the volatility spillover from the international crude oil market to China’s refined oil market gradually increases,and the BRENT price variation has an increasing impact on the refined oil wholesale price variation.The PCA-BP model could serve as a candidate tool for forecasting China’s refined oil wholesale prices.
文摘The paper reviewed the refining and marketing business of both domestic and international oil companies, and tried to figure out the gap of domestic refining enterprises in terms of the refinery scale, processing unil configuration, stream factor and competitive edge as compared to overseas refineries. The paper also concluded that the net margin of domestic refineries is about $ 1.0/bbl lower than that of the overseas refineries, and proposed some ideas to sharpen the competitive edge of Chinese refining industry.
文摘In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.
文摘An analytical method for analyzing the thermal vibration of multi-directional functionally graded porous rectangular plates in fluid media with novel porosity patterns is developed in this study.Mechanical properties of MFG porous plates change according to the length,width,and thickness directions for various materials and the porosity distribution which can be widely applied in many fields of engineering and defence technology.Especially,new porous rules that depend on spatial coordinates and grading indexes are proposed in the present work.Applying Hamilton's principle and the refined higher-order shear deformation plate theory,the governing equation of motion of an MFG porous rectangular plate in a fluid medium(the fluid-plate system)is obtained.The fluid velocity potential is derived from the boundary conditions of the fluid-plate system and is used to compute the extra mass.The GalerkinVlasov solution is used to solve and give natural frequencies of MFG porous plates with various boundary conditions in a fluid medium.The validity and reliability of the suggested method are confirmed by comparing numerical results of the present work with those from available works in the literature.The effects of different parameters on the thermal vibration response of MFG porous rectangular plates are studied in detail.These findings demonstrate that the behavior of the structure within a liquid medium differs significantly from that within a vacuum medium.Thereby,they offer appropriate operational approaches for the structure when employed in various mediums.
基金supported by the Open Project of Key Laboratory of Aerospace EDLA,CASC(No.EDL19092208)。
文摘A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.
基金supported by the project number of“China Agricultural Research System funded by the Ministry of Agriculture”CARS-14,the Key Project of Science and Technology of Henan Province (201300110600)the“Double First-Class”Project for Postgraduate Academic Innovation Enhancement Programme of Henan University of Technology (HAUTSYL2023TS16)Education and Teaching Reform Research and Practice Project in School of International Education,Henan University of Technology (GJXY202407).
文摘This study explores the utilization of various chemometric analytical methods for determining the quality of pressed sesame oil with different adulteration levels of refined sesame oil using UV spectral fingerprints.The goal of this study was to provide a reliable tool for assessing the quality of sesame oil.The UV spectra of 51 samples of pressed sesame oil and 420 adulterated samples with refined sesame oil were measured in the range of 200-330 nm.Various classification and prediction methods,including linear discrimination analysis(LDA),support vector machines(SVM),soft independent modeling of class analogy(SIMCA),partial least squares regression(PLSR),support vector machine regression(SVR),and back-propagation neural network(BPNN),were employed to analyze the UV spectral data of pressed sesame oil and adulterated sesame oil.The results indicated that SVM outperformed the other classification methods in qualitatively identifying adulterated sesame oil,achieving an accuracy of 96.15%,a sensitivity of 97.87%,and a specificity of 80%.For quantitative analysis,BPNN yielded the best prediction results,with an R^(2) value of 0.99,RMSEP of 2.34%,and RPD value of 10.60(LOD of 8.60%and LOQ of 28.67%).Overall,the developed models exhibited significant potential for rapidly identifying and predicting the quality of sesame oil.
基金supported by the NSFC(11871257,12071130)supported by the NSFC(11971165)。
文摘In this article,we first establish an asymptotically sharp result on the higher order Fréchet derivatives for bounded holomorphic mappings f(x)=f(0)+∞∑s=1Dskf(0)(x^(sk))/(sk)!:B_(X)→B_(Y),where B_X is the unit ball of X.We next give a sharp result on the first order Fréchet derivative for bounded holomorphic mappings F(X)=F(0+)∞∑s=KD^(s)f(0)(x^(8)/s!):B_(X)→B_(Y),where B_(X)is the unit ball of X.The results that we derive include some results in several complex variables,and extend the classical result in one complex variable to several complex variables.
文摘Over the past decade,China’s refined oil market has experienced considerable growth and fluctuations.Gasoline consumption has generally followed the growth rate of vehicle equipment,with fluctuations influenced by travel frequency;aviation fuel consumption has seen stable growth following the end of COVID-19,while diesel consumption has been affected by multiple factors including demand and policy.With the rapid development of new energy vehicles and alternative fuels,the gasoline and diesel market has essentially peaked,yet domestic production of refined oil continues to grow,leading to an increasingly prominent oversupply issue.To achieve the dual carbon goals,the Chinese government has introduced a series of policies that have a profound impact on the refined oil market.Facing resource surplus and market demand changes,the refining industry needs to optimize production capacity structure,and oil products retail companies face transformation pressure.The article aims to provide market analysis and recommendations,serving as a reference for relevant enterprises and policymakers.
文摘The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
文摘A complete mesh free adaptive algorithm （MFAA）, with solution adaptation and geometric adaptation, is developed to improve the resolution of flow features and to replace traditional global refinement techniques in structured grids. Unnecessary redundant points and elements are avoided by using the mesh free local clouds refinement technology in shock influencing regions and regions near large curvature places on the boundary. Inviscid compressible flows over NACA0012 and RAE2822 airfoils are computed. Finally numerical results validate the accuracy of the above method.
文摘Vacuum sintering and ball milling methods were employed in the preparation process of Ti-C grain refine- ment and the ability of refiners with varying ratios of Ti and C to refine ZL111 crystal grains was tested. The refinement effect of the Ti-C ratios on tensile strength, elongation percentage, Brinell hardness, pro-eutectoid αAl and the size of the Si phase of ZL111, after modification by rare-earth and strontium nitrate, were studied by means of metallographic examination, SEM and mechanical property tests. The results show that there is an obvious increase in the tensile strength and elongation percentage of refined ZL111 with these new Ti and C refiner compounding powders, while Brinell hardness remained more or less constant. The pro-eutectoid αAl is considerably reduced in size and the Si phase shows a finer and rounder structure. The refiner exhibits a good grain refining performance when the Ti-C ratio is 25:1, for Al crystals can favorably easily form nuclei and grow up along the TiC surface thanks to the TiAl3 generated by sur- plus Ti and Al. The mechanical properties have clearly been improved by the addition of strontium nitrate to ZL111. The effective factors in the modification of mechanical properties of ZL111 are in order of importance: strontium nitrate, Ti-C ratio and rare earth.
文摘The oil refining and petrochemical industry in China has made great achievements after decades of development, and its capacity has already ranked second in the world. However, the refining industry is suffering some challenges, such as severe overcapacity at present, and has entered a new economic normal, in which the technological progress develops rapidly, the demand for green and low-carbon development is stricter, the market competition is increasingly fiercer and the profit margins are gradually narrowing. In such a situation, informatization and its new technologies are driving the significant reforming of manufacturing patterns, marketing patterns, management and decision-making patterns. Intelligent development is the inevitable choice for the transformation and upgrading of oil refining and petrochemical industry. It is suggested that the intelligent evaluating model and method should be adopted to enterprise’s intelligentializing transformation and upgrading by laying a solid foundation of digital refinery and implemenation of digital upgrading.
文摘Based upon a generalized variational principle, which relaxed the inter element continuity requirements, a novel refined hybrid Mindlin plate element is developed, its non linear element stiffness matrices are decomposed into a series of matrices with respect to the assumed strain modes. The formulation presented in this paper is different from any other non linear mixed/hybrid element formulation all successful experience of linear hybrid formulation is absorbed into the formulation(adding non conforming modes and realizing orthogonalization) Numerical results show that the present approach is more effective than any other non linear hybrid element formulation over the accuracy and computational efficiency. In addition, non conforming modes can also overcome the shear locking effect.
