Five dominant bacteria strains（A cetobacter sp., Alcdigenes sp., Micrococcus sp., Arthrobacter sp. and Bacillus sp.） and five fungi strains （Cephalosporium sp. Ⅰ, Cephalosporlum sp. Ⅱ, Aspergillus sp. Ⅰ, Aspergi...Five dominant bacteria strains（A cetobacter sp., Alcdigenes sp., Micrococcus sp., Arthrobacter sp. and Bacillus sp.） and five fungi strains （Cephalosporium sp. Ⅰ, Cephalosporlum sp. Ⅱ, Aspergillus sp. Ⅰ, Aspergillus sp. Ⅱ and Fusarium sp.） isolated from petroleum-contaminated soil were used to assess the potential capability of mineral oil and PAH enhanced degradation separately and jointly using the batch liquid medium cultivation with diesel oil spiked at 1000 mg/L. The experiment was performed on a reciprocal shaker in the darkness at 25℃ to 30℃ for 100 d. The dynamic variation in the activity of microbial inoculators in each treatment and the degradation of the target pollutants during the period of experiment were monitored. Results showed a more rapid biodegradation of mineral oil and PAHs at the beginning of the experiment （about 20 d） by dominant bacteria, fungi and their mixture than that of the indigenous microorganisms, however, thereafter an opposite trcnd was exhibited that the removal ratio by indigenous microorganisms was superior to any other dominant treatments and the tendency lasted till the end of the experiment, indicating the limited competitive capability of dominant microorganisms to degrade the contaminants, and the natural selection of indigenous microorganisms for use in the removal of the contaminants. At the end of the experiment, the removal ratio of mineral oil ranged from 56.8 % to 79.2 % and PAHs ranged from 96.8 % to 99.1% in each treatment by microbial inoculators,展开更多
Fluid insulating medium is used for electrical insulation and provides a cooling medium in high voltage power transformers. Due to this reason, petroleum based mineral oil (transformer oil) is mostly used for a number...Fluid insulating medium is used for electrical insulation and provides a cooling medium in high voltage power transformers. Due to this reason, petroleum based mineral oil (transformer oil) is mostly used for a number of years which holds the benefit of cost effectiveness and good flow rate. This benefit leads to more requirements of oil that may cause oil scarcity in the near future. In order to overcome the scarcity in forthcoming years many research works focus on identifying the best approach for regeneration of oils. In this paper, activated carbon obtained from the agricultural waste is used which acts as the absorbent of impurities. Use of activated carbon is a perfect approach for regeneration of oils. Critical characteristics such as breakdown voltage, flash point, fire point and viscosity are measured for the pure and aged mineral oil with and without adding activated carbon. By this approach it is found that the activated carbon with used oil 1, used oil 2 and fresh oil provides continuous improvement of properties as per IEC (International Electrotechnical Commission) and ASTM (American Society for Testing and Materials) standards which will reduce the oil consumption and cost. From the analysis, it reveals that mineral oil with activated carbon has better properties and the use of activated carbon is the best practice of regeneration of oils.展开更多
The effect of mineral oil on the mechanical properties and fractographs of Fe3(Al,Cr,Zr) in termetallic alloy has been investigated. The results show that the tensile ductility of the Fe3(Al,Cr,Zr) alloy tested in oil...The effect of mineral oil on the mechanical properties and fractographs of Fe3(Al,Cr,Zr) in termetallic alloy has been investigated. The results show that the tensile ductility of the Fe3(Al,Cr,Zr) alloy tested in oil is comparable with the results obtained in oxygen and is in sensitive to strain rate. The fracture mode of the Fe3(Al,Cr,Zr) alloy treated at 700℃/1.5 h and tested in oil, is cleavage and with dimples in some areas.展开更多
Parameter quantification principle of three-dimensional(3-D) fluorescent spe ctrum and its realization technique are studied. The portab le fiber-optic fluorescent measurer for mineral oil is given. Thr ee parameters ...Parameter quantification principle of three-dimensional(3-D) fluorescent spe ctrum and its realization technique are studied. The portab le fiber-optic fluorescent measurer for mineral oil is given. Thr ee parameters of the exciting light wavelength, the wavelength and the intensity of the fluorescent light excited by the measured oil are expressed with 3-D co ordinates and are processed so as to be sampled again and to be curve fitted.展开更多
This study provides a rapid method for quantification of mineral oil in rapeseed oil using near-infrared spectroscopy.The data were processed by direct orthogonal signal correction(DOSC),successive projections algorit...This study provides a rapid method for quantification of mineral oil in rapeseed oil using near-infrared spectroscopy.The data were processed by direct orthogonal signal correction(DOSC),successive projections algorithm(SPA),partial least squares,and principal component regression(PCR).Good correlation coefficients(R)of 0.998 and root-mean-squared error(RMSE)of 0.005 were obtained,and the DOSC-SPA-PCR model was identified as the optimal method.A satisfactory accuracy with R and RMSE of prediction by DOSC-SPA-PCR of 0.990 and 0.006,was obtained.The results demonstrate that the proposed methodology is a promising method for the rapid quantitative detection of mineral oil in vegetable oil.展开更多
This paper is aimed at the streamers in natural esters （vegetable oils） in point--plane electrode arrangement under lightning impulse voltage. The shape, stopping length, velocity and current of streamers are invest...This paper is aimed at the streamers in natural esters （vegetable oils） in point--plane electrode arrangement under lightning impulse voltage. The shape, stopping length, velocity and current of streamers are investigated. Six untreated commercial oils extracted from grape seeds, sunflower and rape seeds, corn, rice and sesame that could constitute potential liquids for high voltage applications are tested. A naphthenic mineral oil is also tested for comparison. It＇s shown that the streamers are filamentary for both polarities. For a given voltage, the stopping lengths （Lf） of streamers are longer when the point is positive than when it is negative; also, except mineral oil when the point is negative, the values of Lf-are very close in all tested oils. The streamers＇ velocities are in the same range for all vegetable oils and they vary between 0.4 km/s and 1.2 km/s for positive polarity and 0.2 km/s and 0.8 km/s for negative polarity.展开更多
The behaviors of creeping streamer progressed in the narrow gap with the range of 0.1 mm to 0.2 mm between the pressboard mounted a BSE （back side electrode） and the acrylic resin plate were carried out in PFAE （pa...The behaviors of creeping streamer progressed in the narrow gap with the range of 0.1 mm to 0.2 mm between the pressboard mounted a BSE （back side electrode） and the acrylic resin plate were carried out in PFAE （palm fatty acid ester） oil under variable impulse voltage up to -4-140 kVpeak with ＋1.2/50 μs and ±1.2/1,000μs waveforms. The growth of positive and negative streamers depends on the gap space between two solid dielectrics. And the distinctive polarities of impulse voltage affect in the streamer length and flashover voltage between needle and counter electrodes as well. By decreasing the gap space, the flashover voltage largely increased while the mean velocity of positive streamer significantly decreased under the both polarities of impulse voltage. These results have been compared to commercial mineral oil （transformer oil： JIS-C2320）. It is shown that the behaviors of creeping discharge in both oils elegantly reveal the distinctive phenomena.展开更多
The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies ...The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies and chemical species of the worn surfaces were analyzed by scanning electron microscope （SEM） and X-ray photoelectron spectroscope （XPS）, respectively. The test results indicated that the three fatty acyl amino acids could effectively improve the anti-wear and friction-reducing abilities of the HVI 350 mineral oil. The improvement in anti-wear and friction-reducing abilities of the mineral oil by the related amino acids was mainly ascribed to the formation of a composite boundary lubrication film due to the adsorption of amino acids on the friction surfaces.展开更多
Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 years.However,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet dev...Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 years.However,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation oil.Consequently,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation oils.Mixed insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base oils.This article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance technology.Through these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.展开更多
Applied experiments were conducted in the palm orchard in the Nubaria region. The orchard includes the varieties of Al-Barhi (imported) and Zaghloul (local) to examine the efficacy of some natural materials alone and ...Applied experiments were conducted in the palm orchard in the Nubaria region. The orchard includes the varieties of Al-Barhi (imported) and Zaghloul (local) to examine the efficacy of some natural materials alone and in combination with some pesticides against the Red Palm Weevil Rhynchophorus ferrugineus (RPW) that infects palm trees in Egypt. Most insects caught by light traps, which have a role in the spread of the red palm weevil in palm groves, appear in early February and March. Peak numbers for the month of May until September namely Phyllgnathus excavatus. Pseudophilus testaceus, Phonapata frontalis, and Oryctes elegans. The neglected gardens of date palms are more compensating for insect infestation than those maintained in terms of agricultural and pest control services. Individual injection of insecticide (Mosspilan) was the most potent against RPW-infested Barhi var. with a recovery rate of 91.7%, followed by Selikron at 80%, and finally Saydon at 37.5%. Injection of the car oil used with Mosspilan followed by Selikron was effective against RPW. No significant difference between treatments of injection (F-value: 1.2). Mixing injection of mineral oils with chemical pesticides is effective against red palm weevil after two successive seasons. As a result, the pesticide was poured around the affected palm root, with a low recovery rate. There is no effect of palm spray. The best way to control the red palm weevil is the method of injecting the tested material (single or mixed) with the pure pesticide into the trunk of the infected palm tree. The tested pesticide residues gradually decrease as the period after application is prolonged with an average loss of 0.12, 0.02 and 0.07 ppm after 90 consecutive days. .展开更多
Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling ...Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling is responsible for 40%of the usage.Therefore,this research proposes the immersion cooling method to solving the high energy consumption of data centers by cooling its component using two types of dielectric fluids.Four stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and durability.Furthermore,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 h.The results of this study show that the immersion cooling reduces 13℃ lower temperature than the conventional cooling method which means it saves more energy consumption in the data center.The most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan rotation.Furthermore,the cooling performance of the dielectric fluids shows that the mineral oil(MO)is better than the virgin coconut oil(VCO).In durability experiment,there are no components damage after five months immersed in the fluid.展开更多
The effects of the mechanical factors with applied loads on the tribological performance of refined,bleached and deodorised(RBD) palm stearin(PS) were studied using a four-ball tribotester.All the RBD PS results were ...The effects of the mechanical factors with applied loads on the tribological performance of refined,bleached and deodorised(RBD) palm stearin(PS) were studied using a four-ball tribotester.All the RBD PS results were simultaneously compared with the additive-free paraffinic mineral oil(PMO).The experiments were carried out using different loads with a constant speed in order to gain a better understanding of the mechanical processes that occurred during the experiment.For each experiment,the temperature was increased to 75 °C and was run for 1 h.In a mechanical system,lubricant plays an important role in reducing wear and friction.PS exists as a semi-solid at room temperature after the fractionation process from oil palm.Due to the increasing rate of pollution to the environment,vegetable oil was chosen as the test lubricant with regard to its biodegradability.Other advantages of vegetable oil are that it is more easily harvestable and non-toxic compared to petroleum-based oil,which made it a suitable candidate.From the experiment,RBD PS is found to have a better friction constraint reduction compared with additive-free PMO.展开更多
The performance of correlation between the dielectric parameters of Baobab Oil(BAO)and Mongongo Oil(MGO)is evaluated using Artificial Neural Network(ANN).The BAO and MGO naturally own high Unsaturated Fatty Acids(UFAs...The performance of correlation between the dielectric parameters of Baobab Oil(BAO)and Mongongo Oil(MGO)is evaluated using Artificial Neural Network(ANN).The BAO and MGO naturally own high Unsaturated Fatty Acids(UFAs)and are highly biodegradable.The temperature studies and dielectric studies are carried out and found that the Natural Esters(NEs)show a reliable performance over mineral oil-based Transformer Oil(TO).Further the endurance test,Partial Discharge Inception Voltage(PDIV)repetition rate and drop after 30 days,dielectric measurements are done as per the standards of IEC(International Electrotechnical Commission)and ASTM(American Society for Testing and Materials).The NEs show stable performance under PDIV and show minimum repetition rate when compared to the TO.The C10H22 or Kerosene(KER)and NEs mixture prove that the NE-based transformer fluids show lesser tendency to hydro peroxidation.The C10H22 acts as a thinning agent and reduces the ageing rate of the NEs,and this leads to slower rate of water saturation.This in turn increases the thermal conductivity of the oil and nearly a 30-days thermal ageing of the oil samples at 90°C shows better strength of liquid insulation.The performance of association between the dielectric properties like breakdown voltage and water content,dissipation factor and thermal conduc-tivity prove that the NEs show consistent performance and is a better substitute for the mineral oil-based TO.展开更多
文摘Five dominant bacteria strains（A cetobacter sp., Alcdigenes sp., Micrococcus sp., Arthrobacter sp. and Bacillus sp.） and five fungi strains （Cephalosporium sp. Ⅰ, Cephalosporlum sp. Ⅱ, Aspergillus sp. Ⅰ, Aspergillus sp. Ⅱ and Fusarium sp.） isolated from petroleum-contaminated soil were used to assess the potential capability of mineral oil and PAH enhanced degradation separately and jointly using the batch liquid medium cultivation with diesel oil spiked at 1000 mg/L. The experiment was performed on a reciprocal shaker in the darkness at 25℃ to 30℃ for 100 d. The dynamic variation in the activity of microbial inoculators in each treatment and the degradation of the target pollutants during the period of experiment were monitored. Results showed a more rapid biodegradation of mineral oil and PAHs at the beginning of the experiment （about 20 d） by dominant bacteria, fungi and their mixture than that of the indigenous microorganisms, however, thereafter an opposite trcnd was exhibited that the removal ratio by indigenous microorganisms was superior to any other dominant treatments and the tendency lasted till the end of the experiment, indicating the limited competitive capability of dominant microorganisms to degrade the contaminants, and the natural selection of indigenous microorganisms for use in the removal of the contaminants. At the end of the experiment, the removal ratio of mineral oil ranged from 56.8 % to 79.2 % and PAHs ranged from 96.8 % to 99.1% in each treatment by microbial inoculators,
文摘Fluid insulating medium is used for electrical insulation and provides a cooling medium in high voltage power transformers. Due to this reason, petroleum based mineral oil (transformer oil) is mostly used for a number of years which holds the benefit of cost effectiveness and good flow rate. This benefit leads to more requirements of oil that may cause oil scarcity in the near future. In order to overcome the scarcity in forthcoming years many research works focus on identifying the best approach for regeneration of oils. In this paper, activated carbon obtained from the agricultural waste is used which acts as the absorbent of impurities. Use of activated carbon is a perfect approach for regeneration of oils. Critical characteristics such as breakdown voltage, flash point, fire point and viscosity are measured for the pure and aged mineral oil with and without adding activated carbon. By this approach it is found that the activated carbon with used oil 1, used oil 2 and fresh oil provides continuous improvement of properties as per IEC (International Electrotechnical Commission) and ASTM (American Society for Testing and Materials) standards which will reduce the oil consumption and cost. From the analysis, it reveals that mineral oil with activated carbon has better properties and the use of activated carbon is the best practice of regeneration of oils.
文摘The effect of mineral oil on the mechanical properties and fractographs of Fe3(Al,Cr,Zr) in termetallic alloy has been investigated. The results show that the tensile ductility of the Fe3(Al,Cr,Zr) alloy tested in oil is comparable with the results obtained in oxygen and is in sensitive to strain rate. The fracture mode of the Fe3(Al,Cr,Zr) alloy treated at 700℃/1.5 h and tested in oil, is cleavage and with dimples in some areas.
基金KeyTaskofScientificInstrumentScienceandTechnology!(No .96-A2 3 -A - 2 - 0 3 1)
文摘Parameter quantification principle of three-dimensional(3-D) fluorescent spe ctrum and its realization technique are studied. The portab le fiber-optic fluorescent measurer for mineral oil is given. Thr ee parameters of the exciting light wavelength, the wavelength and the intensity of the fluorescent light excited by the measured oil are expressed with 3-D co ordinates and are processed so as to be sampled again and to be curve fitted.
基金partially supported by the National Natural Science Foundation of China(NSFC)(No.61775140)。
文摘This study provides a rapid method for quantification of mineral oil in rapeseed oil using near-infrared spectroscopy.The data were processed by direct orthogonal signal correction(DOSC),successive projections algorithm(SPA),partial least squares,and principal component regression(PCR).Good correlation coefficients(R)of 0.998 and root-mean-squared error(RMSE)of 0.005 were obtained,and the DOSC-SPA-PCR model was identified as the optimal method.A satisfactory accuracy with R and RMSE of prediction by DOSC-SPA-PCR of 0.990 and 0.006,was obtained.The results demonstrate that the proposed methodology is a promising method for the rapid quantitative detection of mineral oil in vegetable oil.
文摘This paper is aimed at the streamers in natural esters （vegetable oils） in point--plane electrode arrangement under lightning impulse voltage. The shape, stopping length, velocity and current of streamers are investigated. Six untreated commercial oils extracted from grape seeds, sunflower and rape seeds, corn, rice and sesame that could constitute potential liquids for high voltage applications are tested. A naphthenic mineral oil is also tested for comparison. It＇s shown that the streamers are filamentary for both polarities. For a given voltage, the stopping lengths （Lf） of streamers are longer when the point is positive than when it is negative; also, except mineral oil when the point is negative, the values of Lf-are very close in all tested oils. The streamers＇ velocities are in the same range for all vegetable oils and they vary between 0.4 km/s and 1.2 km/s for positive polarity and 0.2 km/s and 0.8 km/s for negative polarity.
文摘The behaviors of creeping streamer progressed in the narrow gap with the range of 0.1 mm to 0.2 mm between the pressboard mounted a BSE （back side electrode） and the acrylic resin plate were carried out in PFAE （palm fatty acid ester） oil under variable impulse voltage up to -4-140 kVpeak with ＋1.2/50 μs and ±1.2/1,000μs waveforms. The growth of positive and negative streamers depends on the gap space between two solid dielectrics. And the distinctive polarities of impulse voltage affect in the streamer length and flashover voltage between needle and counter electrodes as well. By decreasing the gap space, the flashover voltage largely increased while the mean velocity of positive streamer significantly decreased under the both polarities of impulse voltage. These results have been compared to commercial mineral oil （transformer oil： JIS-C2320）. It is shown that the behaviors of creeping discharge in both oils elegantly reveal the distinctive phenomena.
基金the financial support from National Natural Science Foundation of China(project No.50975282)Chongqing Science Foundation for Outstanding Youth(project No. CSTC2008,BA4037)
文摘The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies and chemical species of the worn surfaces were analyzed by scanning electron microscope （SEM） and X-ray photoelectron spectroscope （XPS）, respectively. The test results indicated that the three fatty acyl amino acids could effectively improve the anti-wear and friction-reducing abilities of the HVI 350 mineral oil. The improvement in anti-wear and friction-reducing abilities of the mineral oil by the related amino acids was mainly ascribed to the formation of a composite boundary lubrication film due to the adsorption of amino acids on the friction surfaces.
基金supported in part by the National Natural Science Foundation of China under Grant 52077015the National Natural Science Foundation of China under Grant HWQB2023001the Graduate Research and Innovation Foundation of Chongqing,China under Grant CYB23025.
文摘Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 years.However,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation oil.Consequently,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation oils.Mixed insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base oils.This article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance technology.Through these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.
文摘Applied experiments were conducted in the palm orchard in the Nubaria region. The orchard includes the varieties of Al-Barhi (imported) and Zaghloul (local) to examine the efficacy of some natural materials alone and in combination with some pesticides against the Red Palm Weevil Rhynchophorus ferrugineus (RPW) that infects palm trees in Egypt. Most insects caught by light traps, which have a role in the spread of the red palm weevil in palm groves, appear in early February and March. Peak numbers for the month of May until September namely Phyllgnathus excavatus. Pseudophilus testaceus, Phonapata frontalis, and Oryctes elegans. The neglected gardens of date palms are more compensating for insect infestation than those maintained in terms of agricultural and pest control services. Individual injection of insecticide (Mosspilan) was the most potent against RPW-infested Barhi var. with a recovery rate of 91.7%, followed by Selikron at 80%, and finally Saydon at 37.5%. Injection of the car oil used with Mosspilan followed by Selikron was effective against RPW. No significant difference between treatments of injection (F-value: 1.2). Mixing injection of mineral oils with chemical pesticides is effective against red palm weevil after two successive seasons. As a result, the pesticide was poured around the affected palm root, with a low recovery rate. There is no effect of palm spray. The best way to control the red palm weevil is the method of injecting the tested material (single or mixed) with the pure pesticide into the trunk of the infected palm tree. The tested pesticide residues gradually decrease as the period after application is prolonged with an average loss of 0.12, 0.02 and 0.07 ppm after 90 consecutive days. .
基金This work is financially supported by the Ministry of Research and Technology of Indonesia(BRIN)in the project called“Penggunaan Immersion Cooling untukMeningkatkan Efisiensi Energi Data Center”.
文摘Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling is responsible for 40%of the usage.Therefore,this research proposes the immersion cooling method to solving the high energy consumption of data centers by cooling its component using two types of dielectric fluids.Four stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and durability.Furthermore,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 h.The results of this study show that the immersion cooling reduces 13℃ lower temperature than the conventional cooling method which means it saves more energy consumption in the data center.The most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan rotation.Furthermore,the cooling performance of the dielectric fluids shows that the mineral oil(MO)is better than the virgin coconut oil(VCO).In durability experiment,there are no components damage after five months immersed in the fluid.
基金Project supported by the Research University Grant from Universiti Teknologi Malaysia (No. 00J02)the Fundamental Research Grant Scheme from the Ministry of Higher Education (MOHE) (No. 78604)the E-Science Grant from the Ministry of Science,Technology and Innovation of Malaysia (No. 79396)
文摘The effects of the mechanical factors with applied loads on the tribological performance of refined,bleached and deodorised(RBD) palm stearin(PS) were studied using a four-ball tribotester.All the RBD PS results were simultaneously compared with the additive-free paraffinic mineral oil(PMO).The experiments were carried out using different loads with a constant speed in order to gain a better understanding of the mechanical processes that occurred during the experiment.For each experiment,the temperature was increased to 75 °C and was run for 1 h.In a mechanical system,lubricant plays an important role in reducing wear and friction.PS exists as a semi-solid at room temperature after the fractionation process from oil palm.Due to the increasing rate of pollution to the environment,vegetable oil was chosen as the test lubricant with regard to its biodegradability.Other advantages of vegetable oil are that it is more easily harvestable and non-toxic compared to petroleum-based oil,which made it a suitable candidate.From the experiment,RBD PS is found to have a better friction constraint reduction compared with additive-free PMO.
文摘The performance of correlation between the dielectric parameters of Baobab Oil(BAO)and Mongongo Oil(MGO)is evaluated using Artificial Neural Network(ANN).The BAO and MGO naturally own high Unsaturated Fatty Acids(UFAs)and are highly biodegradable.The temperature studies and dielectric studies are carried out and found that the Natural Esters(NEs)show a reliable performance over mineral oil-based Transformer Oil(TO).Further the endurance test,Partial Discharge Inception Voltage(PDIV)repetition rate and drop after 30 days,dielectric measurements are done as per the standards of IEC(International Electrotechnical Commission)and ASTM(American Society for Testing and Materials).The NEs show stable performance under PDIV and show minimum repetition rate when compared to the TO.The C10H22 or Kerosene(KER)and NEs mixture prove that the NE-based transformer fluids show lesser tendency to hydro peroxidation.The C10H22 acts as a thinning agent and reduces the ageing rate of the NEs,and this leads to slower rate of water saturation.This in turn increases the thermal conductivity of the oil and nearly a 30-days thermal ageing of the oil samples at 90°C shows better strength of liquid insulation.The performance of association between the dielectric properties like breakdown voltage and water content,dissipation factor and thermal conduc-tivity prove that the NEs show consistent performance and is a better substitute for the mineral oil-based TO.
