According to many years of experimental summary, the technical demands, process control, seed test, seed quality and work record (ledger management) of cleaning processing of feeding millet seeds in Hebei Province w...According to many years of experimental summary, the technical demands, process control, seed test, seed quality and work record (ledger management) of cleaning processing of feeding millet seeds in Hebei Province were studied, and specific measures and technical indicators of the technical regulations were analyzed to provide normalized, standardized, industrial and marketization technical support for the cleaning processing of feeding millet seeds.展开更多
In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a "Carosello", a structural hollow element made of clay, placed in arches...In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a "Carosello", a structural hollow element made of clay, placed in arches, in domes or even in the walls of buildings such as churches and houses. Our results show that laser ablation techniques is able to remove the surface impurity patina from artifacts surface without changes the chemical composition and the optical properties of ceramic. Moreover, because the laser cleaning heats only locally the surface of the sample, this method don't preclude the possibility to apply on artifact the thermo-luminescence dating process.展开更多
Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solu...Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.展开更多
In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the...In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism. It is also compared with the present cleaning system with double channel applied to some combines, such as the Commandor 112CS/ 228CS combines of Claas Corporation in Germany and the MAXIMIZERTMombincs of John Deerc company in U.S.A. It may omit one sieve and the preclcaner and simlify the transmission mechanism. The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01 kg/ s.展开更多
Objective To evaluate the application of enzyme in instrument cleaning for hospital sterile reprocessing and different factors that impact the enzyme activity.Methods Standard soil objects for instrument cleaning qual...Objective To evaluate the application of enzyme in instrument cleaning for hospital sterile reprocessing and different factors that impact the enzyme activity.Methods Standard soil objects for instrument cleaning quality evaluation,as testing coupons,were identified and used to evaluate different cleaning processes designed with varied conditions.Between testing groups using enzymatic detergent versus non-enzymatic detergent,the amount of residual protein on the testing coupons were quantified and compared at different soaking time(10min,20min,30min,45min and 60min).Then,within the enzymatic detergent group,different testing conditions were further explored by adjusting factors,in⁃cluding the soaking temperature(25°C,30°C and 45°C),use solution pH(7.0,8.0),and enzyme dosing(1/80,1/40,1/20,3/40,1/10 and 3/20 in v/v).Then,through an observational comparative study for each testing condition,the time needed to achieve a complete soil removal through visual inspection of the testing coupons was documented for analyses.Results In the test of enzymatic detergent versus non-enzymatic detergent,the non-enzymatic group did not show an obvious decline in the residual protein amount(1069μg at 10 min vs.1042μg at 60 min),whereas the enzymatic group showed significant decrease in residual protein quantity(947μg at 10 min vs.620μg at 60 min).Meanwhile,the amounts of the residual protein at different time points in the enzyme group(947μg at 10 min,864μg at 20 min,812μg at 30 min,691μg at 45 min,and 620μg at 60 min)were consistently lower than those at the same time schedule in the non-enzyme group(1069μg at 10 min,1069μg at 20 min,1067μg at 30 min,1059μg at 45 min,and 1042μg at 60 min).Furthermore,within the enzymatic group,the soaking temperature,use solution pH and enzyme dosing factors all appear to impact the enzyme activity and significantly contribute to the cleaning outcomes.Specifi⁃cally,the higher soaking temperature,higher use solution pH and higher enzyme dosing showed 58.4%,20.0%and 34.4%time reduction to completely remove the soil on the testing coupons,respectively.Conclusion Enzyme seems to play a significant role in the instrument cleaning process for hospital sterile reprocessing.The soaking temperature,cleaning use solution pH,and enzyme dosing all appear to be critical factors impacting the enzyme activity and thus the overall cleaning outcomes.In practice,cleaning process verification should be considered to ensure the optimal use conditions for enzyme cleaning performance are well-understood and consistently achieved at the facility level.展开更多
High voltage lines are one of the main ways for carrying electric energy. To do so high voltage insulators are needed to insulate these lines from the supporting towers. Glass, ceramic and polymer insulators are widel...High voltage lines are one of the main ways for carrying electric energy. To do so high voltage insulators are needed to insulate these lines from the supporting towers. Glass, ceramic and polymer insulators are widely used. Generally high voltage insulators are exposed to weather where humidity, from rain and moist, together with pollution allows accumulation of unwanted material on the surface of the insulator. Cleaning procedures are then needed to remove such material and avoid short-circuiting. The most commonly used cleaning methods are hand cleaning using chemicals that need turning off the main and water jet, which allows keeping the line in service. In this work we explore the possibility of using laser ablation for cleaning high voltage ceramic insulators. It is demonstrated that cleaning can be accomplished by a two-step process. First a Q-switched Nd: YAG laser is used to ablate the unwanted material. The second step is to use a free running Nd: YAG laser to restore the surface hydrophobicity of ceramic insulator, which is affected in the first process step.展开更多
Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal...Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.展开更多
The dominant status of coal on the energy production and consumption structure of China will not be changed in the middle period of this century. To realize highly efficient utilization of coal,low pollution and low c...The dominant status of coal on the energy production and consumption structure of China will not be changed in the middle period of this century. To realize highly efficient utilization of coal,low pollution and low cost are great and impendent tasks. These difficult problems can be almost resolved through establishing large-scale pithead power stations using two-stage highly efficient dry coal-cleaning system before coal burning,which is a highly efficient,clean and economical strategy considering the current energy and environmental status of China. All these will be discussed in detail in this paper.展开更多
Striving for cleaner production is a sought-after manufacturing philosophy.Friction stir welding(FSW)is a joiningtechnique with par excellence and far less invasive to the environment than even best conventional weldi...Striving for cleaner production is a sought-after manufacturing philosophy.Friction stir welding(FSW)is a joiningtechnique with par excellence and far less invasive to the environment than even best conventional welding processes.It is energyefficient and free from consumables,affluent and radiations.It is,thus,accepted as a clean welding process that can produceacceptable quality joints.It suffers from some major challenges of defects of its own kind that subject the process open toimprovements so as to prove itself a reliable production process.This study presents a holistic characterization of defects commonlyfound in FSW joints.The finding of the present study reveals that most defects are caused by inadequate heat generation,impropermaterial movement around the pin and inadequate material consolidation behind the pin.The amount of heat generation andmaterial stirring depends on several FSW parameters which may lead to the defect formation,if not selected properly.The resultsreported in this work are derived from sound literature support and experimentation.Prescriptions are made in the form ofcharacteristics of defects such as likelihood of their location,main responsible parameters along with the recommendations forminimizing them.展开更多
As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cl...As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cleaning,and fabrication of laser-induced micro-/nano-structures, has been demonstrated to yield smooth, clean, functional surfaces and effective joining. Laser polishing is an advanced, highly efficient, and ecofriendly polishing technology. This study demonstrated the laser polishing of a selective laser-melted Inconel 718(IN718) superalloy and a titanium alloy sample. The surface roughnesses Raand Rzof the IN718 superalloy were respectively reduced from 8 and 33 μm to 0.2 and 0.8 μm, and the Raof the titanium alloy was reduced from 9.8 μm to 0.2 μm.Moreover, the wear resistance and corrosion resistance of the IN718 were apparently improved. As another surface-related processing method, laser cleaning was used to clean terminal blocks. Almost all the contaminants were removed, as verified by the absence of their chemical compositions and the decreased surface roughness. In addition, a superhydrophobic surface with a contact angle of over 160° and sliding angle of b8° on stainless steel was obtained by laser texturing treatment. These results demonstrate the high potential of laser processing in the scientific, technological, and industrial fields.展开更多
The cleaning of copper interconnect chemical mechanical polishing(CMP) is a key process in integrated circuits(ICs) fabrication. Colloidal silica, which is used as the abrasive material in copper CMP slurry, is consid...The cleaning of copper interconnect chemical mechanical polishing(CMP) is a key process in integrated circuits(ICs) fabrication. Colloidal silica, which is used as the abrasive material in copper CMP slurry, is considered as the main particle contamination. Abrasive particle residuals can cause device failure which need to be removed efficiently. In this paper, a type of CMP cleaner was used for particle removal using a cleaning solution consisting of FA/O Ⅱ chelating agent and FA/O Ⅰ surfactant. By varying the parameters of brush rotation speed, brush gap,and de-ionized water(DIW) flow rate,a series of experiments were performed to determine the best cleaning results. Atomic force microscope(AFM) measurement was used to characterise the surface morphology of the copper surface and the removal of abrasive particles. A scanning electron microscope(SEM) with EDX was used to observe and analyze the particles shape and elements. The optima parameters of CMP cleaner were obtained. Under those conditions, the abrasive silica particles were removed effectively.展开更多
The objective of this paper was to investigate the practicability of coagulation-immersed membrane process during low-temperature period through the study of steady operation,chemical cleaning methods,water quality an...The objective of this paper was to investigate the practicability of coagulation-immersed membrane process during low-temperature period through the study of steady operation,chemical cleaning methods,water quality and agent consumption.Experimental results showed that:membrane performance decreases with the reduction of temperature,but low temperature has little effect on stable operation of immersed membrane when coagulation as pretreatment.EFM with 1200 mg/L sodium hypochlorite after every 48 filtration cycles was made for reducing membrane fouling efficiently,and the method,with 1.5% sodium hydroxide and 3500 mg/L sodium hypochlorite for 10 h and then 2% hydrochloric acid for 4 h,is an appropriate cleaning method under low temperature.Compared with convention treatment process,immersed membrane process not only has same agent consumption,but also permeated water quality is more superior such as fine removal effect on turbidity with average 0.10 NTU.Therefore,coagulation-immersed membrane process is more appropriate for increasing water quality demand and the treatment of low turbidity and low temperature water.展开更多
A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost sample...A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco®<sup></sup> and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC Kinetex<sup>TM</sup> 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g<sup>-1</sup> and 2 ng·g<sup>-1</sup> for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.展开更多
Improvement of coking properties of sub-bituminous coal (A) and bituminous coal (B) was done using blended organic solvents, namely, n-methyl-2-pyrrolidinone (NMP) and ethylenediamine (EDA). Various solvent bl...Improvement of coking properties of sub-bituminous coal (A) and bituminous coal (B) was done using blended organic solvents, namely, n-methyl-2-pyrrolidinone (NMP) and ethylenediamine (EDA). Various solvent blends were employed for the coal extraction under the total reflux condition. A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R&D, Jamshedpur (India) to separate out the dissolved coking fraction from the solvent-coal mixture. Membrane separations were carried out in a batch cell, and around 75 % recovered NMP was reused. The fractionated coal properties were determined using proximate and ultimate analyses. In the case of bituminous coal, the ash and sulfur contents were decreased by 99.3 % and 79.2 %, respectively, whereas, the carbon content was increased by 23.9 % in the separated coal fraction. Three different cleaning agents, namely deionized water, sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.展开更多
Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-p...Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.展开更多
An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in hi...An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in high yields (86% - 97%) at room temperature under solvent-free conditions. Deprotection of the resulting acylals has also been attained by using the same catalysts under microwave irradiation. This method consistently has advantage of excellent yields (82% - 96%) and a short reaction time (3 - 4 min).展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(20120304201)~~
文摘According to many years of experimental summary, the technical demands, process control, seed test, seed quality and work record (ledger management) of cleaning processing of feeding millet seeds in Hebei Province were studied, and specific measures and technical indicators of the technical regulations were analyzed to provide normalized, standardized, industrial and marketization technical support for the cleaning processing of feeding millet seeds.
文摘In this work, the results of a study of laser ablation cleaning process on ceramic artifacts are presented. The experiments were conducted on a "Carosello", a structural hollow element made of clay, placed in arches, in domes or even in the walls of buildings such as churches and houses. Our results show that laser ablation techniques is able to remove the surface impurity patina from artifacts surface without changes the chemical composition and the optical properties of ceramic. Moreover, because the laser cleaning heats only locally the surface of the sample, this method don't preclude the possibility to apply on artifact the thermo-luminescence dating process.
文摘Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.
文摘In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism. It is also compared with the present cleaning system with double channel applied to some combines, such as the Commandor 112CS/ 228CS combines of Claas Corporation in Germany and the MAXIMIZERTMombincs of John Deerc company in U.S.A. It may omit one sieve and the preclcaner and simlify the transmission mechanism. The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01 kg/ s.
文摘Objective To evaluate the application of enzyme in instrument cleaning for hospital sterile reprocessing and different factors that impact the enzyme activity.Methods Standard soil objects for instrument cleaning quality evaluation,as testing coupons,were identified and used to evaluate different cleaning processes designed with varied conditions.Between testing groups using enzymatic detergent versus non-enzymatic detergent,the amount of residual protein on the testing coupons were quantified and compared at different soaking time(10min,20min,30min,45min and 60min).Then,within the enzymatic detergent group,different testing conditions were further explored by adjusting factors,in⁃cluding the soaking temperature(25°C,30°C and 45°C),use solution pH(7.0,8.0),and enzyme dosing(1/80,1/40,1/20,3/40,1/10 and 3/20 in v/v).Then,through an observational comparative study for each testing condition,the time needed to achieve a complete soil removal through visual inspection of the testing coupons was documented for analyses.Results In the test of enzymatic detergent versus non-enzymatic detergent,the non-enzymatic group did not show an obvious decline in the residual protein amount(1069μg at 10 min vs.1042μg at 60 min),whereas the enzymatic group showed significant decrease in residual protein quantity(947μg at 10 min vs.620μg at 60 min).Meanwhile,the amounts of the residual protein at different time points in the enzyme group(947μg at 10 min,864μg at 20 min,812μg at 30 min,691μg at 45 min,and 620μg at 60 min)were consistently lower than those at the same time schedule in the non-enzyme group(1069μg at 10 min,1069μg at 20 min,1067μg at 30 min,1059μg at 45 min,and 1042μg at 60 min).Furthermore,within the enzymatic group,the soaking temperature,use solution pH and enzyme dosing factors all appear to impact the enzyme activity and significantly contribute to the cleaning outcomes.Specifi⁃cally,the higher soaking temperature,higher use solution pH and higher enzyme dosing showed 58.4%,20.0%and 34.4%time reduction to completely remove the soil on the testing coupons,respectively.Conclusion Enzyme seems to play a significant role in the instrument cleaning process for hospital sterile reprocessing.The soaking temperature,cleaning use solution pH,and enzyme dosing all appear to be critical factors impacting the enzyme activity and thus the overall cleaning outcomes.In practice,cleaning process verification should be considered to ensure the optimal use conditions for enzyme cleaning performance are well-understood and consistently achieved at the facility level.
文摘High voltage lines are one of the main ways for carrying electric energy. To do so high voltage insulators are needed to insulate these lines from the supporting towers. Glass, ceramic and polymer insulators are widely used. Generally high voltage insulators are exposed to weather where humidity, from rain and moist, together with pollution allows accumulation of unwanted material on the surface of the insulator. Cleaning procedures are then needed to remove such material and avoid short-circuiting. The most commonly used cleaning methods are hand cleaning using chemicals that need turning off the main and water jet, which allows keeping the line in service. In this work we explore the possibility of using laser ablation for cleaning high voltage ceramic insulators. It is demonstrated that cleaning can be accomplished by a two-step process. First a Q-switched Nd: YAG laser is used to ablate the unwanted material. The second step is to use a free running Nd: YAG laser to restore the surface hydrophobicity of ceramic insulator, which is affected in the first process step.
基金financially supported by National Natural Science Foundation of China(No.52274171)Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining Fund(No.EC2023015)+1 种基金Excellent Youth Project of Universities in Anhui Province(No.2023AH030042)Unveiled List of Bidding Projects of Shanxi Province(No.20201101001)。
文摘Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.
文摘The dominant status of coal on the energy production and consumption structure of China will not be changed in the middle period of this century. To realize highly efficient utilization of coal,low pollution and low cost are great and impendent tasks. These difficult problems can be almost resolved through establishing large-scale pithead power stations using two-stage highly efficient dry coal-cleaning system before coal burning,which is a highly efficient,clean and economical strategy considering the current energy and environmental status of China. All these will be discussed in detail in this paper.
基金the University Grants Commission (UGC) for its financial assistance (vide sanction order No. F.3-40/2012(SAP-Ⅱ)) under its SAP (DRS-Ⅰ) sanctioned to the Department of Mechanical Engineering for the project entitled Friction Stir Welding and Ultrasonic Machiningfinancially supported by the King Saud University, Vice Deanship of Research Chairs
文摘Striving for cleaner production is a sought-after manufacturing philosophy.Friction stir welding(FSW)is a joiningtechnique with par excellence and far less invasive to the environment than even best conventional welding processes.It is energyefficient and free from consumables,affluent and radiations.It is,thus,accepted as a clean welding process that can produceacceptable quality joints.It suffers from some major challenges of defects of its own kind that subject the process open toimprovements so as to prove itself a reliable production process.This study presents a holistic characterization of defects commonlyfound in FSW joints.The finding of the present study reveals that most defects are caused by inadequate heat generation,impropermaterial movement around the pin and inadequate material consolidation behind the pin.The amount of heat generation andmaterial stirring depends on several FSW parameters which may lead to the defect formation,if not selected properly.The resultsreported in this work are derived from sound literature support and experimentation.Prescriptions are made in the form ofcharacteristics of defects such as likelihood of their location,main responsible parameters along with the recommendations forminimizing them.
基金National Key Research and Development Program of China under Grant 2018YFB1107700, 2018YFB1107400, and 2016YFB1102503National Key Basic Research Program of China under Grant 2015CB059900+1 种基金National Natural Science Foundation of China under Grant 51705013Beijing Natural Science Foundation under Grant J170002
文摘As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cleaning,and fabrication of laser-induced micro-/nano-structures, has been demonstrated to yield smooth, clean, functional surfaces and effective joining. Laser polishing is an advanced, highly efficient, and ecofriendly polishing technology. This study demonstrated the laser polishing of a selective laser-melted Inconel 718(IN718) superalloy and a titanium alloy sample. The surface roughnesses Raand Rzof the IN718 superalloy were respectively reduced from 8 and 33 μm to 0.2 and 0.8 μm, and the Raof the titanium alloy was reduced from 9.8 μm to 0.2 μm.Moreover, the wear resistance and corrosion resistance of the IN718 were apparently improved. As another surface-related processing method, laser cleaning was used to clean terminal blocks. Almost all the contaminants were removed, as verified by the absence of their chemical compositions and the decreased surface roughness. In addition, a superhydrophobic surface with a contact angle of over 160° and sliding angle of b8° on stainless steel was obtained by laser texturing treatment. These results demonstrate the high potential of laser processing in the scientific, technological, and industrial fields.
基金Project supported by the Major National Science and Technology Special Projects(No.2016ZX02301003-004-007)the Natural Science Foundation of China(No.61704046)+1 种基金the Scientific Innovation Grant for Excellent Young Scientists of Hebei University of Technology(No.2015007)the Hebei Natural Science Foundation Project(No.F2018202174)
文摘The cleaning of copper interconnect chemical mechanical polishing(CMP) is a key process in integrated circuits(ICs) fabrication. Colloidal silica, which is used as the abrasive material in copper CMP slurry, is considered as the main particle contamination. Abrasive particle residuals can cause device failure which need to be removed efficiently. In this paper, a type of CMP cleaner was used for particle removal using a cleaning solution consisting of FA/O Ⅱ chelating agent and FA/O Ⅰ surfactant. By varying the parameters of brush rotation speed, brush gap,and de-ionized water(DIW) flow rate,a series of experiments were performed to determine the best cleaning results. Atomic force microscope(AFM) measurement was used to characterise the surface morphology of the copper surface and the removal of abrasive particles. A scanning electron microscope(SEM) with EDX was used to observe and analyze the particles shape and elements. The optima parameters of CMP cleaner were obtained. Under those conditions, the abrasive silica particles were removed effectively.
基金Sponsored by the Tianjin Municipal Science and Technology Commission (Grant No. 05FZZDSH00500)
文摘The objective of this paper was to investigate the practicability of coagulation-immersed membrane process during low-temperature period through the study of steady operation,chemical cleaning methods,water quality and agent consumption.Experimental results showed that:membrane performance decreases with the reduction of temperature,but low temperature has little effect on stable operation of immersed membrane when coagulation as pretreatment.EFM with 1200 mg/L sodium hypochlorite after every 48 filtration cycles was made for reducing membrane fouling efficiently,and the method,with 1.5% sodium hydroxide and 3500 mg/L sodium hypochlorite for 10 h and then 2% hydrochloric acid for 4 h,is an appropriate cleaning method under low temperature.Compared with convention treatment process,immersed membrane process not only has same agent consumption,but also permeated water quality is more superior such as fine removal effect on turbidity with average 0.10 NTU.Therefore,coagulation-immersed membrane process is more appropriate for increasing water quality demand and the treatment of low turbidity and low temperature water.
文摘A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco®<sup></sup> and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC Kinetex<sup>TM</sup> 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g<sup>-1</sup> and 2 ng·g<sup>-1</sup> for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.
文摘Improvement of coking properties of sub-bituminous coal (A) and bituminous coal (B) was done using blended organic solvents, namely, n-methyl-2-pyrrolidinone (NMP) and ethylenediamine (EDA). Various solvent blends were employed for the coal extraction under the total reflux condition. A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R&D, Jamshedpur (India) to separate out the dissolved coking fraction from the solvent-coal mixture. Membrane separations were carried out in a batch cell, and around 75 % recovered NMP was reused. The fractionated coal properties were determined using proximate and ultimate analyses. In the case of bituminous coal, the ash and sulfur contents were decreased by 99.3 % and 79.2 %, respectively, whereas, the carbon content was increased by 23.9 % in the separated coal fraction. Three different cleaning agents, namely deionized water, sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.
基金support from the National Natural Science Foundation of China(Nos.52120105007,51834010)the National Science Fund for Distinguished Young Scholars(No.52222403).
文摘Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.
文摘An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in high yields (86% - 97%) at room temperature under solvent-free conditions. Deprotection of the resulting acylals has also been attained by using the same catalysts under microwave irradiation. This method consistently has advantage of excellent yields (82% - 96%) and a short reaction time (3 - 4 min).