The effect of refined petroleum products on the activities of selected enzymes (catalase and dehydrogenase) was studied. There was a significant decrease (p kerosene > diesel > engine oil. However, a significant...The effect of refined petroleum products on the activities of selected enzymes (catalase and dehydrogenase) was studied. There was a significant decrease (p kerosene > diesel > engine oil. However, a significant increase (p diesel > petrol > engine oil. On the whole the results reveal that refined petroleum products alter soil biochemistry.展开更多
Road tankers are the most used means of transporting petroleum product to end users due to its cost effectiveness and energy-efficiency. The cylindrical tank has been well designed for by ASME VIII divisions 1 and 2 u...Road tankers are the most used means of transporting petroleum product to end users due to its cost effectiveness and energy-efficiency. The cylindrical tank has been well designed for by ASME VIII divisions 1 and 2 using analytical equations. Petrol tankers are not circular but elliptical probably for stability during transportation. This paper has used the finite element method to investigate in-plane displacements and Von-Mises stresses in both circular and elliptical cylindrical tanks under full loading. An elliptical OANDO? tanker of 66.78 m3volume and shell thickness of0.2 mmand an equivalent volume circular cylindrical tank was used for the simulation. MATLAB? was used to generate geometrical mesh model of the petroleum tankers, extract element coordinates and conduct the finite element analysis. Plane strain condition was used in analyzing a section of the petroleum tanker. It was observed that an equivalent volume circular cylindrical tank was under a higher internal pressure (16,858 N/m2) compared to the elliptical cylinder (14,480 N/m2). Von-Mises stress and in-plane displacements showed direct linear relationships with internal fluid pressure. Von-Mises stress in the elliptical tank was found to be lower (5.7 × 106 N/m2) than for the circular tank (8 × 106 N/m2). In plane displacements was zero in the longitudinal direction for both tanks and of the order of 10-4 mm in the y-direction for both tanks with the circular larger by about 2.5 × 10-3 cm. So in addition to tank stability on the lorry, the Von-Mises stresses were lower as well for the elliptical tank. It was also observed that Von-Mises stresses were far below the yield stress of the steel plate. However, the effect of weldment area on lowering of yield stress was not studied. Stress values were validated using analytical method and found to be insignificantly different (P > 0.05).展开更多
Background: toxic gases and fumes prompted from petrol and gas stations imply their disabling and deadly risks on human lungs. Aim of Work: The aim of this work was to assess the pulmonary function derangements in pet...Background: toxic gases and fumes prompted from petrol and gas stations imply their disabling and deadly risks on human lungs. Aim of Work: The aim of this work was to assess the pulmonary function derangements in petrol pump workers at Al-Medina Al-Munawara city. Patients and Methods: This cross sectional study was conducted on 189 cases out of them in control group (group I) with age and sex matched healthy adult males gathered from nonsmokers students and employees in Taibah University. The study group (group II) comprised of 89 males who were working in different petrol pump stations. History, clinical examination and pulmonary functional assessment were carried out by using portable spirometry, Co detector and puls oximeter. Results: The study’s results showoed that the lung function parameters (FEV1, FVC, PEFR, FEFR25% - 75%) were significantly reduced in petrol pump workers (Group II) as compared to the values for these parameters in subjects belonging to Group II (Control group), Similar findings were observed in previous studies on pulmonary functions in petrol-pump workers. This finding specified the restrictive nature of pulmonary involvement in the study group. Measurement of the exhaled CO was slightly higher in Group II than Group I. Conclusion: Fuel vapors and fumes in petrol stations showed direct incapacitating impact on workers pulmonary functions regarding spirometric measurements showing predominantly restrictive pattern and to less extent obstructive. Exhaled CO level was higher in addition to hypoxemia identified in these cases.展开更多
20112390 Chen Wei (College of Geo - Resources and Information,China University of Petroleum,Dongying 257061,China); Wu Zhiping Study on Hydrocarbon Migration along Fault Strike(Journal of China University of Petroleum...20112390 Chen Wei (College of Geo - Resources and Information,China University of Petroleum,Dongying 257061,China); Wu Zhiping Study on Hydrocarbon Migration along Fault Strike(Journal of China University of Petroleum,ISSN1673-5005。展开更多
This study assessed the impact of petrol service stations on physico-chemical water quality in Port Harcourt metropolis, Rivers State. This threw light on the extent of damage and alteration of water quality in Port H...This study assessed the impact of petrol service stations on physico-chemical water quality in Port Harcourt metropolis, Rivers State. This threw light on the extent of damage and alteration of water quality in Port Harcourt metropolis as a result of the proliferation of petrol service stations especially the condition of ground and nearby surface water. This serves as a useful tool to government and regulatory authorities for planning especially due to lack of central water supply system in Port Harcourt metropolis. The parameters studied were sampled, measured and analyzed using in situ and other standard methods. Remarkable results above permissible limits of interest for physicochemical parameter analysis revealed pH values from 4.6 to 6.8, electrical conductivity from 0.002 µS/cm to 0.42 µS/cm, salinity from 3 ppm to 4050 ppm, and temperatures from 19.9˚C to 32.6˚C. Total dissolved solids (TDS) varied from 7 ppm to 1000 ppm, biochemical oxygen demand (BOD) from 0.167 mg/L to 2.167 mg/L, chemical oxygen demand (COD) from 0.257 mg/L to 3.253 mg/L, and dissolved oxygen (DO) concentrations from 1.70 mg/L to 4.30 mg/L. Specifically, water samples from NNPC Filling Station (Choba) and Eneka Pond displayed “Poor” water quality with WQI values of 112.003 and 112.076, respectively. Similarly, ALLTEC Filling Station (Eneka) and TOTAL Filling Station (Rumuomasi) had “Poor” water quality with WQI values of 173.707 and 180.946, respectively. In contrast, Excelsis Filling Station (Akpajo) demonstrated “Good” water quality with a WQI of 85.2072, while Total Filling Stations (Slaughter) and Choba River revealed “unsuitable for drinking” water quality with WQI values of 552.461 and 654.601, respectively. Slaughter River also indicated very poor water quality with a WQI of 442.024. The physicochemical and nutrient analyses of the water samples showed that activities of the filling stations within the study area may have polluted groundwater in the environment posing poor aesthetics and great health risk to consumers of the water bodies. The findings underscore the need for immediate remediation efforts and stricter regulatory measures to protect water quality. The study concluded that surface and groundwater near petrol service stations in Port Harcourt are unfit for drinking and irrigation purposes without adequate treatment.展开更多
Lead is a toxic metal that affects many organ systems and functions in humans. In the majority of adults, chronic lead poisoning comes from exposures to work places and can occur in numerous work settings, such as man...Lead is a toxic metal that affects many organ systems and functions in humans. In the majority of adults, chronic lead poisoning comes from exposures to work places and can occur in numerous work settings, such as manufacturing, lead smelting and refinement, or due to use of batteries, pigments, solder, ammunitions, paint, car radiators, cable and wires, certain cosmetics. In some countries, lead is added to petrol. We present a rare case of gastric dilation caused by long-term petrol ingestion. A 16-year-old young man was admitted to our hospital due to a 6-mo history of exhaustion, dizziness, nausea, abdominal cramps and constipation. X-ray examination revealed dilated stomach descending into the pelvis and small bowel distension. After a long clinical observation, we found that the reason for the chronic lead poisoning of the patient was due to a 3-year history of petrol ingestion. The patient spontaneously recovered and stomach returned to its normal position and size. Lead poisoning should be taken into consideration in all unexplained cases of gastric dilation.展开更多
The petrol truck routing problem is an important part of the petrol supply chain.This study focuses on determining routes for distributing petrol products from a depot to petrol stations with the objective of minimizi...The petrol truck routing problem is an important part of the petrol supply chain.This study focuses on determining routes for distributing petrol products from a depot to petrol stations with the objective of minimizing the total travel cost and the fixed cost required to use the trucks.We propose a mathematical model that considers petrol trucks returning to a depot multiple times and develop a heuristic algorithm based on a local branch-and-bound search with a tabu list and the Metropolis acceptance criterion.In addition,an approach that accelerates the solution process by adding several valid inequalities is presented.In this study,the trucks are homogeneous and have two compartments,and each truck can execute at most three tasks daily.The sales company arranges the transfer amount and the time windows for each station.The performance of the proposed algorithm is evaluated by comparing its results with the optimal results.In addition,a real-world case of routing petrol trucks in Beijing is studied to demonstrate the effectiveness of the proposed approach.展开更多
To investigate highway petrol station replenishment in initiative distribution mode,this paper develops a mixed-integer linear programming(MILP)model with minimal operational costs that includes loading costs,unloadin...To investigate highway petrol station replenishment in initiative distribution mode,this paper develops a mixed-integer linear programming(MILP)model with minimal operational costs that includes loading costs,unloading costs,transport costs and the costs caused by unpunctual distribution.Based on discrete representation,the working day is divided into equal time intervals,and the truck distribution process is decomposed into a pair of tasks including driving,standby,rest,loading and unloading.Each truck must execute one task during a single interval,and the currently executing task is closely related to the preceding and subsequent tasks.By accounting for predictive time-varying sales at petrol stations,real-time road congestion and a series of operational constraints,the proposed model produces the optimal truck dispatch,namely,a detailed task assignment for all trucks during each time interval.The model is tested on a real-world case of a replenishment system comprising eight highway petrol stations,one depot,one garage and eight trucks to demonstrate its applicability and accuracy.展开更多
Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average da...Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average daily traffic(AADT)in 1986 were determined.Pb was found to have a significant correlation(P<0.01)with AADT.No correlation was found between Al, Ba,Cd,Cr,Cu,Fe,Mn,Ni,and Zn with respect to AADT.A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.1989 Academic Press,Inc.展开更多
Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-...Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-and-error method and then the vehicle engine is run on the dynamometer to show the actual engine performance. Obviously the current practice involves a large amount of time and money, and then may even fail to tune up the engine optimally because a formal performance model of the engine has not been determined yet. With an emerging technique, Support Vector Machines (SVM), the approximate per- formance model of a petrol vehicle engine can be determined by training the sample engine performance data acquired from the dynamometer. The number of dynamometer tests for an engine tune-up can therefore be reduced because the estimated engine performance model can replace the dynamometer tests to a certain extent. In this paper, the construction, validation and accuracy of the model are discussed. The study showed that the predicted results agree well with the actual test results. To illustrate the significance of the SVM methodology, the results were also compared with that regressed using multilayer feedforward neural networks.展开更多
In this study, the forecasting capabilities of a new class of nonlinear econometric models, namely, the LSTAR-LST-GARCH-RBF and MLP models are evalu- ated. The models are utilized to model and to forecast the daily re...In this study, the forecasting capabilities of a new class of nonlinear econometric models, namely, the LSTAR-LST-GARCH-RBF and MLP models are evalu- ated. The models are utilized to model and to forecast the daily returns of crude oil prices. Many financial time series are subjected to leptokurtic distribution, heavy tails, and nonlinear conditional volatility. This characteristic feature leads to deterioration in the forecast capabilities of tradi- tional models such as the ARCH and GARCH models. According to the empirical findings, the oil prices and their daily returns could be classified as possessing nonlinearity in the conditional mean and conditional variance processes. Several model groups are evaluated： （i） the models pro- posed in the first group are the LSTAR-LST-GARCH models that are augmented with fractional integration and asymmetric power terms （FIGARCH, APGARCH, and FIAPGARCH）; （ii） the models proposed in the second group are the LSTAR-LST-GARCH models further aug- mented with MLP and RBF type neural networks. The models are compared in terms of MSE, RMSE, and MAE criteria for in-sample and out-of-sample forecast capabili- ties. The results show that the LSTAR based and neural network augmented models provide important gains over the single-regime baseline GARCH models, followed by the LSTAR-LST-GARCH type models in terms of mod- eling and forecasting volatility in crude oil prices.展开更多
This study is focused on investigation of the resistivity property of polluted soils and the consequent effect on the growth rate of plants. The method involves construction of an inexpensive apparatus for measuring t...This study is focused on investigation of the resistivity property of polluted soils and the consequent effect on the growth rate of plants. The method involves construction of an inexpensive apparatus for measuring the electrical resistivity of polluted soil in the laboratory based on application of Ohm’s law. Some pollutants such as petrol, kerosene and brine were added to the soil samples and the electrical resistivity was determined. The results showed that the quantity of petrol and kerosene added to the soil were directly proportional to the resistivity of the soil while the salt concentration varied inversely with resistivity. On the other hand, the study showed that Kerosene, Petrol and Salt solution of different concentrations have an adverse effect on the growth and development of the bean plants.展开更多
rather 一词含义及用法较多,现把常用的用法及结构分别总结如下:一、rather1.修饰动词时意为“倒是”、“(在某种程度上)有点”。I rather think everything is going to come out allright.我倒是认为一切事情最后会圆满解决的。I rath...rather 一词含义及用法较多,现把常用的用法及结构分别总结如下:一、rather1.修饰动词时意为“倒是”、“(在某种程度上)有点”。I rather think everything is going to come out allright.我倒是认为一切事情最后会圆满解决的。I rather like the smell of petrol.展开更多
Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service li...Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.展开更多
Fuel is a very important factor and has considerable influence on the air quality in the environment,which is the heart of the world.The increase of vehi-cles in lived-in areas results in greater emission of carbon par...Fuel is a very important factor and has considerable influence on the air quality in the environment,which is the heart of the world.The increase of vehi-cles in lived-in areas results in greater emission of carbon particles in the envir-onment.Adulterated fuel causes more contaminated particles to mix with breathing air and becomes the main source of dangerous pollution.Adulteration is the mixing of foreign substances in fuel,which damages vehicles and causes more health problems in living beings such as humans,birds,aquatic life,and even water resources by emitting high levels of hydrocarbons,nitrogen oxides,and carbon monoxide.Most frequent blending liquids are lubricants and kerosene in the petrol,and its adulteration is a considerable problem that adds to environ-mental pollution.This study focuses on detecting the adulteration in petrol using sensors and machine learning algorithms.A modified evanescent wave opticalfiber sensor with discrete wavelet transform is proposed for classification of adult-erated data from the samples.Furthermore,support vector machine classifier is used for accurate categorization.The sensor isfirst tested with fuel and numerical data is classified based on machine learning algorithms.Finally,the result is eval-uated with less error and high accuracy of 99.9%,which is higher than all existing techniques.展开更多
文摘The effect of refined petroleum products on the activities of selected enzymes (catalase and dehydrogenase) was studied. There was a significant decrease (p kerosene > diesel > engine oil. However, a significant increase (p diesel > petrol > engine oil. On the whole the results reveal that refined petroleum products alter soil biochemistry.
文摘Road tankers are the most used means of transporting petroleum product to end users due to its cost effectiveness and energy-efficiency. The cylindrical tank has been well designed for by ASME VIII divisions 1 and 2 using analytical equations. Petrol tankers are not circular but elliptical probably for stability during transportation. This paper has used the finite element method to investigate in-plane displacements and Von-Mises stresses in both circular and elliptical cylindrical tanks under full loading. An elliptical OANDO? tanker of 66.78 m3volume and shell thickness of0.2 mmand an equivalent volume circular cylindrical tank was used for the simulation. MATLAB? was used to generate geometrical mesh model of the petroleum tankers, extract element coordinates and conduct the finite element analysis. Plane strain condition was used in analyzing a section of the petroleum tanker. It was observed that an equivalent volume circular cylindrical tank was under a higher internal pressure (16,858 N/m2) compared to the elliptical cylinder (14,480 N/m2). Von-Mises stress and in-plane displacements showed direct linear relationships with internal fluid pressure. Von-Mises stress in the elliptical tank was found to be lower (5.7 × 106 N/m2) than for the circular tank (8 × 106 N/m2). In plane displacements was zero in the longitudinal direction for both tanks and of the order of 10-4 mm in the y-direction for both tanks with the circular larger by about 2.5 × 10-3 cm. So in addition to tank stability on the lorry, the Von-Mises stresses were lower as well for the elliptical tank. It was also observed that Von-Mises stresses were far below the yield stress of the steel plate. However, the effect of weldment area on lowering of yield stress was not studied. Stress values were validated using analytical method and found to be insignificantly different (P > 0.05).
文摘Background: toxic gases and fumes prompted from petrol and gas stations imply their disabling and deadly risks on human lungs. Aim of Work: The aim of this work was to assess the pulmonary function derangements in petrol pump workers at Al-Medina Al-Munawara city. Patients and Methods: This cross sectional study was conducted on 189 cases out of them in control group (group I) with age and sex matched healthy adult males gathered from nonsmokers students and employees in Taibah University. The study group (group II) comprised of 89 males who were working in different petrol pump stations. History, clinical examination and pulmonary functional assessment were carried out by using portable spirometry, Co detector and puls oximeter. Results: The study’s results showoed that the lung function parameters (FEV1, FVC, PEFR, FEFR25% - 75%) were significantly reduced in petrol pump workers (Group II) as compared to the values for these parameters in subjects belonging to Group II (Control group), Similar findings were observed in previous studies on pulmonary functions in petrol-pump workers. This finding specified the restrictive nature of pulmonary involvement in the study group. Measurement of the exhaled CO was slightly higher in Group II than Group I. Conclusion: Fuel vapors and fumes in petrol stations showed direct incapacitating impact on workers pulmonary functions regarding spirometric measurements showing predominantly restrictive pattern and to less extent obstructive. Exhaled CO level was higher in addition to hypoxemia identified in these cases.
文摘20112390 Chen Wei (College of Geo - Resources and Information,China University of Petroleum,Dongying 257061,China); Wu Zhiping Study on Hydrocarbon Migration along Fault Strike(Journal of China University of Petroleum,ISSN1673-5005。
文摘This study assessed the impact of petrol service stations on physico-chemical water quality in Port Harcourt metropolis, Rivers State. This threw light on the extent of damage and alteration of water quality in Port Harcourt metropolis as a result of the proliferation of petrol service stations especially the condition of ground and nearby surface water. This serves as a useful tool to government and regulatory authorities for planning especially due to lack of central water supply system in Port Harcourt metropolis. The parameters studied were sampled, measured and analyzed using in situ and other standard methods. Remarkable results above permissible limits of interest for physicochemical parameter analysis revealed pH values from 4.6 to 6.8, electrical conductivity from 0.002 µS/cm to 0.42 µS/cm, salinity from 3 ppm to 4050 ppm, and temperatures from 19.9˚C to 32.6˚C. Total dissolved solids (TDS) varied from 7 ppm to 1000 ppm, biochemical oxygen demand (BOD) from 0.167 mg/L to 2.167 mg/L, chemical oxygen demand (COD) from 0.257 mg/L to 3.253 mg/L, and dissolved oxygen (DO) concentrations from 1.70 mg/L to 4.30 mg/L. Specifically, water samples from NNPC Filling Station (Choba) and Eneka Pond displayed “Poor” water quality with WQI values of 112.003 and 112.076, respectively. Similarly, ALLTEC Filling Station (Eneka) and TOTAL Filling Station (Rumuomasi) had “Poor” water quality with WQI values of 173.707 and 180.946, respectively. In contrast, Excelsis Filling Station (Akpajo) demonstrated “Good” water quality with a WQI of 85.2072, while Total Filling Stations (Slaughter) and Choba River revealed “unsuitable for drinking” water quality with WQI values of 552.461 and 654.601, respectively. Slaughter River also indicated very poor water quality with a WQI of 442.024. The physicochemical and nutrient analyses of the water samples showed that activities of the filling stations within the study area may have polluted groundwater in the environment posing poor aesthetics and great health risk to consumers of the water bodies. The findings underscore the need for immediate remediation efforts and stricter regulatory measures to protect water quality. The study concluded that surface and groundwater near petrol service stations in Port Harcourt are unfit for drinking and irrigation purposes without adequate treatment.
文摘Lead is a toxic metal that affects many organ systems and functions in humans. In the majority of adults, chronic lead poisoning comes from exposures to work places and can occur in numerous work settings, such as manufacturing, lead smelting and refinement, or due to use of batteries, pigments, solder, ammunitions, paint, car radiators, cable and wires, certain cosmetics. In some countries, lead is added to petrol. We present a rare case of gastric dilation caused by long-term petrol ingestion. A 16-year-old young man was admitted to our hospital due to a 6-mo history of exhaustion, dizziness, nausea, abdominal cramps and constipation. X-ray examination revealed dilated stomach descending into the pelvis and small bowel distension. After a long clinical observation, we found that the reason for the chronic lead poisoning of the patient was due to a 3-year history of petrol ingestion. The patient spontaneously recovered and stomach returned to its normal position and size. Lead poisoning should be taken into consideration in all unexplained cases of gastric dilation.
基金the Program of “Study on Optimization and Supply-side Reliability of Oil Product Supply Chain Logistics System” funded under the National Natural Science Foundation of China, Grant Number 51874325
文摘The petrol truck routing problem is an important part of the petrol supply chain.This study focuses on determining routes for distributing petrol products from a depot to petrol stations with the objective of minimizing the total travel cost and the fixed cost required to use the trucks.We propose a mathematical model that considers petrol trucks returning to a depot multiple times and develop a heuristic algorithm based on a local branch-and-bound search with a tabu list and the Metropolis acceptance criterion.In addition,an approach that accelerates the solution process by adding several valid inequalities is presented.In this study,the trucks are homogeneous and have two compartments,and each truck can execute at most three tasks daily.The sales company arranges the transfer amount and the time windows for each station.The performance of the proposed algorithm is evaluated by comparing its results with the optimal results.In addition,a real-world case of routing petrol trucks in Beijing is studied to demonstrate the effectiveness of the proposed approach.
基金This work was part of the Program of“Study on Optimization and Supply side Reliability of Oil Product Supply Chain Logistics System”funded under the National Natural Science Foundation of China,grant number 51874325.The authors are grateful to all study participants.
文摘To investigate highway petrol station replenishment in initiative distribution mode,this paper develops a mixed-integer linear programming(MILP)model with minimal operational costs that includes loading costs,unloading costs,transport costs and the costs caused by unpunctual distribution.Based on discrete representation,the working day is divided into equal time intervals,and the truck distribution process is decomposed into a pair of tasks including driving,standby,rest,loading and unloading.Each truck must execute one task during a single interval,and the currently executing task is closely related to the preceding and subsequent tasks.By accounting for predictive time-varying sales at petrol stations,real-time road congestion and a series of operational constraints,the proposed model produces the optimal truck dispatch,namely,a detailed task assignment for all trucks during each time interval.The model is tested on a real-world case of a replenishment system comprising eight highway petrol stations,one depot,one garage and eight trucks to demonstrate its applicability and accuracy.
文摘Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average daily traffic(AADT)in 1986 were determined.Pb was found to have a significant correlation(P<0.01)with AADT.No correlation was found between Al, Ba,Cd,Cr,Cu,Fe,Mn,Ni,and Zn with respect to AADT.A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.1989 Academic Press,Inc.
文摘Modern automotive petrol engine performance is significantly affected by effective tune-up. Current practice of engine tune-up relies on the experience of the automotive engineer, and tune-up is usually done by trial-and-error method and then the vehicle engine is run on the dynamometer to show the actual engine performance. Obviously the current practice involves a large amount of time and money, and then may even fail to tune up the engine optimally because a formal performance model of the engine has not been determined yet. With an emerging technique, Support Vector Machines (SVM), the approximate per- formance model of a petrol vehicle engine can be determined by training the sample engine performance data acquired from the dynamometer. The number of dynamometer tests for an engine tune-up can therefore be reduced because the estimated engine performance model can replace the dynamometer tests to a certain extent. In this paper, the construction, validation and accuracy of the model are discussed. The study showed that the predicted results agree well with the actual test results. To illustrate the significance of the SVM methodology, the results were also compared with that regressed using multilayer feedforward neural networks.
文摘In this study, the forecasting capabilities of a new class of nonlinear econometric models, namely, the LSTAR-LST-GARCH-RBF and MLP models are evalu- ated. The models are utilized to model and to forecast the daily returns of crude oil prices. Many financial time series are subjected to leptokurtic distribution, heavy tails, and nonlinear conditional volatility. This characteristic feature leads to deterioration in the forecast capabilities of tradi- tional models such as the ARCH and GARCH models. According to the empirical findings, the oil prices and their daily returns could be classified as possessing nonlinearity in the conditional mean and conditional variance processes. Several model groups are evaluated： （i） the models pro- posed in the first group are the LSTAR-LST-GARCH models that are augmented with fractional integration and asymmetric power terms （FIGARCH, APGARCH, and FIAPGARCH）; （ii） the models proposed in the second group are the LSTAR-LST-GARCH models further aug- mented with MLP and RBF type neural networks. The models are compared in terms of MSE, RMSE, and MAE criteria for in-sample and out-of-sample forecast capabili- ties. The results show that the LSTAR based and neural network augmented models provide important gains over the single-regime baseline GARCH models, followed by the LSTAR-LST-GARCH type models in terms of mod- eling and forecasting volatility in crude oil prices.
文摘This study is focused on investigation of the resistivity property of polluted soils and the consequent effect on the growth rate of plants. The method involves construction of an inexpensive apparatus for measuring the electrical resistivity of polluted soil in the laboratory based on application of Ohm’s law. Some pollutants such as petrol, kerosene and brine were added to the soil samples and the electrical resistivity was determined. The results showed that the quantity of petrol and kerosene added to the soil were directly proportional to the resistivity of the soil while the salt concentration varied inversely with resistivity. On the other hand, the study showed that Kerosene, Petrol and Salt solution of different concentrations have an adverse effect on the growth and development of the bean plants.
文摘rather 一词含义及用法较多,现把常用的用法及结构分别总结如下:一、rather1.修饰动词时意为“倒是”、“(在某种程度上)有点”。I rather think everything is going to come out allright.我倒是认为一切事情最后会圆满解决的。I rather like the smell of petrol.
文摘Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.
文摘Fuel is a very important factor and has considerable influence on the air quality in the environment,which is the heart of the world.The increase of vehi-cles in lived-in areas results in greater emission of carbon particles in the envir-onment.Adulterated fuel causes more contaminated particles to mix with breathing air and becomes the main source of dangerous pollution.Adulteration is the mixing of foreign substances in fuel,which damages vehicles and causes more health problems in living beings such as humans,birds,aquatic life,and even water resources by emitting high levels of hydrocarbons,nitrogen oxides,and carbon monoxide.Most frequent blending liquids are lubricants and kerosene in the petrol,and its adulteration is a considerable problem that adds to environ-mental pollution.This study focuses on detecting the adulteration in petrol using sensors and machine learning algorithms.A modified evanescent wave opticalfiber sensor with discrete wavelet transform is proposed for classification of adult-erated data from the samples.Furthermore,support vector machine classifier is used for accurate categorization.The sensor isfirst tested with fuel and numerical data is classified based on machine learning algorithms.Finally,the result is eval-uated with less error and high accuracy of 99.9%,which is higher than all existing techniques.
