Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer...Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.展开更多
In view of Chinese eating habits and the ways of cooking, this article described the principle and characteristics of kitchen greasy dirt formations, analysed the main factors influencing the performance of kitchen cl...In view of Chinese eating habits and the ways of cooking, this article described the principle and characteristics of kitchen greasy dirt formations, analysed the main factors influencing the performance of kitchen cleaner formulas, introduced the current situation of development of kitchen cleaners in China, analysed modern consumers＇ demand for kitchen cleaners and discussed the future development trend of kitchen cleaners.展开更多
In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,i...In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,in this study,bionic mole forelimb intelligent row cleaners comprising of a cleaning device and a depth intelligent control system were designed.Via theoretical analysis,computer-based simulation,and test optimized design,the mechanism of bionic cleaners that possessed the forelimb motion morphology and the front claw toe structural morphology of moles was studied,the effects of structural parameters of bionic cleaners on the cleaning quality were clarified.Based on a pressure sensor,a depth intelligent control system was designed,which enhanced the depth stability of the cleaning devices.The types of bionic cleaners were identified by simulation on EDEM software.Then regression equations between different parameters and operation evaluation indices were established,and the optimal parameter combination was identified on Design-Expert software with a rotation radius of 150 mm and a motion deflection angle of 15.8°,at which the cleaning rate was 91.3%.Field tests under the optimal parameter combination showed that bionic cleaners outperformed normal planar cleaners,and the depth intelligent control system could efficiently improve the performance of the row cleaners.The straw cleaning rate of the bionic mole forelimb intelligent row cleaners under total straw mulching fields was 90.9%,which was 21.3%higher than that of normal cleaners,and the ground surfaces after operation satisfied the agricultural requirements of maize no-tillage sowing.展开更多
This study assessed six commercially available in-duct air cleaning devices which are designed to be mounted in the central ventilation system of offices or commercial buildings.The selected devices use different air ...This study assessed six commercially available in-duct air cleaning devices which are designed to be mounted in the central ventilation system of offices or commercial buildings.The selected devices use different air cleaning technologies:mechanical filtration,electrostatic precipitation,gas filtration,ionization/cold plasma,photocatalytic oxidation(PCO)and catalysis under UV light.They were tested against particles,a mixture of volatile organic compounds containing acetone,acetaldehyde,toluene,heptane and formaldehyde,and two bio-contaminants:Aspergillus brasiliensis(fungus)and Staphylococcus epidermidis(bacteria).Two different test rigs were used.The single pass efficiency of each device was determined for three airflow rates,corresponding to face velocities ranging from 0.9 to 2.7 m/s,and two sets of temperature and humidity that are representative of indoor air conditions in wintertime and summertime.The concentration of the chal-lenge volatile organic compounds was also varied in the 30 to 100μg/m^(3)range as a way to characterize their influence on efficiency at realistic concentration levels for non-industrial buildings.Measurements of ozone and formaldehyde concentration downstream of the air cleaners were carried out to determine the emission rate of by-products into the air stream.Finally,the energy issue was addressed by measuring the electric power drawn and pressure loss of the devices.The results showed that two devices,namely a radiant catalytic ionizer and a plasma ionizer,had a very low single pass efficiency against all the challenge pollutants.The association of the plasma ionizer and the electrostatic precipitator did not produce a synergetic effect between the two technologies either,contrary to what their manufacturer claims.Finally,three of the six devices tested were effective in terms of pollutant removal,but only two had an acceptable energy effectiveness in view of their use in low or zero energy buildings.Their energy effectiveness ranged from a few thousand m^(3)/kWh for VOCs at the highest airflow rate(3600 m^(3)/h),to more than 60000 m^(3)/kWh for particles and bio-contaminants at 1200 or 1600 m^(3)/h.These results are at least one order of magnitude higher than the majority of stand-alone air cleaners.Moreover,they suggest that optimal IAQ and energy conditions can be achieved if variable air volume control methods are used to maintain indoor temperature and humidity.展开更多
一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。A It's Sunday afternoon.Mike's family are at home.When Mike and his 4 year-old brother Bruce are__1__in their room,Dad is cleaning the livin...一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。A It's Sunday afternoon.Mike's family are at home.When Mike and his 4 year-old brother Bruce are__1__in their room,Dad is cleaning the living room with the cleaner(吸尘器).展开更多
The aim of this work is to find an alternative lubricating grease formulation that can be produced from renewable and biodegradable sources with minimal risks to human health and the environment.We used a castor oil a...The aim of this work is to find an alternative lubricating grease formulation that can be produced from renewable and biodegradable sources with minimal risks to human health and the environment.We used a castor oil and electrospun cellulose acetate propionate(CAp)as raw materials.We hypothesized that the acetyl and propionyl groups could provide an adequate chemical compatibility with the castor oil and that the electrospun nanostructures could enable improved physical stability by creating a variety of morphologies allowing the tailoring of the rheological and tribological properties of the resulting greases.The experimental results show that the use of electrospun CAp nanostructures can indeed yield physically stable formulations,even when used at low concentrations(3 wt%).The resulting dispersions went through structural transitions due to changes in the thickener morphologies and/or concentration,as shown by oscillatory rheology,oil holding capacity,tackiness,and lubrication performance in metal–metal contact.We found that the formulations,containing smooth or porous CAp nanofibers,at 5 wt%as a thickener,possess suitable rheological and tribological properties with a performance comparable to that of traditional lithium lubricating greases.展开更多
This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and envi...This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and environmental sustainability.The FAHP model was validated using an example of the production of aircraft components(specifically fuselage)employing AM technologies such as Wire Arc Additive Manufacturing(WAAM),laser powder bed fusion(L-PBF),Binder Jetting(BJ),Selective Laser Sintering(SLS),and Laser Metal Deposition(LMD).The selection criteria prioritized eco-friendly manufacturing considerations,including the quality and properties of the final product(e.g.,surface finish,high strength,and corrosion resistance),service and functional requirements,weight reduction for improved energy efficiency(lightweight structures),and environmental responsibility.Sustainability metrics,such as cost-effectiveness,material efficiency,waste minimization,and environmental impact,are central to the evaluation process.A computer-aided modeling approach was also used to simulate the performance of aluminum(AA7075 T6),steel(304),and titanium alloy(Ti6Al4V)for fuselage development.The results demonstrate that MCD approaches such as FAHP can effectively guide the selection of AM technologies that meet functional and technical requirements while minimizing environmental degradation footprints.Furthermore,the aluminumalloy outperformed the other materials investigated in the simulation with the lowest stress concentration and least deformation.This study contributes to advancing cleaner production practices by providing a decision-making framework for sustainable and eco-friendly manufacturing,enabling manufacturers to adopt AM technologies that promote environmental responsibility and sustainable development,while maintaining product quality and performance.展开更多
Shanxi,China’s leading coal-mining province,is feeding more green power into the national grid,heralding an era of cleaner and more sustainable energy.AT the national demonstration base of advanced photovoltaic(PV)te...Shanxi,China’s leading coal-mining province,is feeding more green power into the national grid,heralding an era of cleaner and more sustainable energy.AT the national demonstration base of advanced photovoltaic(PV)technology in Datong City,Shangxi Province-the largest coal producer in China,rows upon rows of solar panels glitter in the sunlight,resembling a twinkling blue ocean.展开更多
Compared with the vacuum continuous magnesium smelting process(RVCMS), its excellent energy saving and emission reduction performance provides a feasible method for green magnesium smelting. In the process of industri...Compared with the vacuum continuous magnesium smelting process(RVCMS), its excellent energy saving and emission reduction performance provides a feasible method for green magnesium smelting. In the process of industrialization, the reduction rate of prefabricated pellets affects the yield of metal magnesium and the utilization of reducing slag. In this paper, the reduction mechanism under different carbonate structures is analyzed by controlled disproportionation of prefabricated pellets and micro-nano simulation. The results show that the low temperature decomposition of NH_(4)·HCO_(3)pore-forming, improve the reduction rate(99.72%) effect is remarkable. Combined with thermodynamics and relative vacuum mechanism, a theoretical model of the relationship between disproportionation pore-forming and reduction rate was established. It was concluded that the energy consumption required to produce per ton of magnesium by adding NH_(4)·HCO_(3)to the prefabricated pellets was reduced by 0.29±0.34 tce, and the carbon emission was reduced by 1.069±1.263 t. The reduction slag had good compressive strength(Side 101.19 N cm^(-2), Bottom 466.4 N cm^(-2)). Compared with the 20 MPa reduction slag sample without pore-forming agent, the side compressive strength increased by 51.66%, and the bottom compressive strength increased by 119.10%. The amount of single furnace filler is increased by more than 50%.展开更多
Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 ex...Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 exhibitors from more than 30 countries including China to address the future of cleaner and more inclusive energy.展开更多
Cleaner air,lower dependency on oil,and lower emissions are just a few reasons to move away from combustion cars.In the wake of the emergence of more environmentally friendly technology,some countries have decided to ...Cleaner air,lower dependency on oil,and lower emissions are just a few reasons to move away from combustion cars.In the wake of the emergence of more environmentally friendly technology,some countries have decided to move away from traditional cars towards electric vehicles (EVs).The rise of the EV industry has created a shift in energy demand from oil-based to battery-based.展开更多
In this study,a cleaner method for separation and recovery of V/W/Na in waste selective catalytic reduction(SCR)catalyst alkaline leaching solution was proposed.The method involved membrane electrolysis followed by io...In this study,a cleaner method for separation and recovery of V/W/Na in waste selective catalytic reduction(SCR)catalyst alkaline leaching solution was proposed.The method involved membrane electrolysis followed by ion morphology pretreatme nt and solvent extraction.An acidic V(Ⅴ)/W(Ⅵ)solution was obtained using the me mbrane electrolysis method without adding any other chemical reagents.In addition,Na was recovered in the form of NaOH by product,avoiding the generation of Na containing wastewater.The electrolysis parameters were investigated,the lowest power consumption of 3063 kW·h·t^(-1)NaOH was obtained at a current density of 125 A·m^(-2)and an initial NaOH concentration of 2 mol·L^(-1).After electrolysis,oxalic acid was added to the acidic V/W containing solution,converting V(Ⅴ)negative ion to V(Ⅳ)positive ion.Since W(Ⅵ)ion state remained in negative form,the generation of heteropolyacid ions(W_(x)V_(y)O_(z)^(n-))was prevented.It was found that under the condition of oxalic acid addition/theoretical consumption 1.2 and reaction temperature 75℃,100%V(Ⅴ)was co nverted to V(Ⅳ4).Using 10%N263+10%noctanol+80%sulfonated kerosene as extractant,the highest W(Ⅵ)/V(Ⅳ)separation coefficient of 7559.76was obtained at pH=1.8,O:A ratio=1:1 and extraction time 15 min.With 2 mol·L^(-1)NaOH as stripping reagent,the W stripping efficiency reached 98.50%at O:A ratio=2:1 after 4-stages of stripping.The enrichment of V remained in the solution was realized using P204 as extractant and 20%(mass)H_(2)SO_(4)as stripping reagent.The parameters of extraction/stripping process were investigated,using 10%P204+10%TBP+80%sulfonated kerosene as extractant,the V extraction efficiency reached 97.50%at O:A ratio=1:2after 4 stages of extraction.Using 20%H_(2)SO_(4)as the stripping reagent,the V stripping efficiency was 98.30%at an O:A ratio of 4:1 after five stage s of stripping.After the entire process,a high-purity VOSO_(4)and Na_(2)WO_(4)product solutions were obtained with V/W recovery efficiency 95.84%/98.50%,separately.This study examined a more effective and cleaner method for separating V/W/Na in Na_(2)WO_(4)/NaVO_(3)solution,which may serve as a reference for the separation and recovery of V/W/Na in waste SCR catalysts.展开更多
Entreprencurship is not something that springs to mind when people think of China.Just a few decides ago being an entrepreneur or small business owner was practically a criminal offense in some areas ol’the country.B...Entreprencurship is not something that springs to mind when people think of China.Just a few decides ago being an entrepreneur or small business owner was practically a criminal offense in some areas ol’the country.But,somehow,over the past few years,China has grown into a startup superpower.’’Startup Kingdom'(see page 28)looks at how the Middle Kingdom came to be one of the most exciting startup markets in the world and some of the展开更多
In the continuous annual wheat-corn cropping area of North China Plain,no-till planting that promotes soil conservation and crop yield while reducing operation cost has been gradually accepted by local farmers.However...In the continuous annual wheat-corn cropping area of North China Plain,no-till planting that promotes soil conservation and crop yield while reducing operation cost has been gradually accepted by local farmers.However,previous wheat residue is the main limiting factor affecting the performance of existing planters in placing seeds at uniform spacing and optimum depth in residue covered fields.In order to solve this problem,a kind of ground-wheel-driven row cleaner was designed,developed and mounted on row units of a four-row pneumatic precision planter.The planter has two adjacent row units equipped with the newly designed row cleaners and the other two adjacent row units equipped with the commonly used inactive row cleaners.This was used for planting at three forward speeds(4 km/h,6 km/h and 8 km/h)into half residue(HR)and whole residue(WR)plots.The amount of residue removal,seeding depth,emergence rate and indices of uniformity in seed spacing(missing-seeding index,quality of feeding index and precision index)were measured.The newly designed row cleaner performed better with regard to residue removal,with the average percentage of residue cleared as 63.0%compared to 40.3%for the inactive row cleaner.For the HR and WR plots,percentage of residue cleared of the newly designed row cleaner reached 57.1%and 68.9%respectively,suggesting that the newly designed row cleaner can work more effectively at high residue level.By contrast,with the percentage of residue cleared of the inactive row cleaner as 43.1%and 37.5%in HR and WR plots,suggesting that the inactive row cleaner just can work effectively under low residue condition.Values of missing-seeding index,QFI,precision index,coefficient of variation of depth and percent emergence for the newly designed row cleaner under whole residue level are comparable to those for the inactive row cleaner under half residue level.The result indicates that the effect of using the newly designed row cleaner is equal to that of reducing surface residue,and can help to maintain the uniformity of seed spacing and seeding depth.The newly designed row cleaner generally performed better at forward speed of 6 km/h,based on the distribution of seeds along rows and seeding depth uniformity.展开更多
Natural ventilation(NV)has been considered a simple and effective method of ventilation.However,the intro-duction of NV does not achieve better indoor air quality(IAQ)when the outdoor atmospheric environment is pollut...Natural ventilation(NV)has been considered a simple and effective method of ventilation.However,the intro-duction of NV does not achieve better indoor air quality(IAQ)when the outdoor atmospheric environment is polluted.Therefore,portable air cleaners(PACs)are increasing in use in recent years,but their effectiveness is highly dependent on the residents’habits.A typical residence in Xi’an,China was selected to examine the effects of the use of NV alone and the use of NV and PACs together on IAQ in the three occupant states,i.e.,unoc-cupied,sleeping and leisure.Parameters,such as temperature,relative humidity,CO_(2),and PM_(2.5)concentration were measured when changing the window opening and the position of the PAC.The results showed that in the unoccupied state,opening the inner door can promote a more uniform thermal and humid environment.In the sleeping state,the I/O ratio of the PM_(2.5)concentration was the lowest when the window opening of the bedroom was 1/2 or 3/4,with a mean value of 0.3.In the leisure state,only using NV,when the purification rate reaches 90%,the mean purification time of each window opening in the living room is 87.5 min.The mean purification time was reduced to 25 min when both NV and PAC were used.The on-site purification efficiencies were 91.0%and 94.5%,when the window opening was 1/2(i.e.,the PAC was placed in the center of the room)and 3/4(i.e.,the PAC was placed away from the outer window),respectively.展开更多
One of the cleaning methods for agricultural materials is based on aerodynamic properties.Pneumatic cleaners are developed on this method.The purpose of this study is to predict the parameters such as fan angle,air ve...One of the cleaning methods for agricultural materials is based on aerodynamic properties.Pneumatic cleaners are developed on this method.The purpose of this study is to predict the parameters such as fan angle,air velocity,and tunnel length,which are used in the design of pneumatic cleaners,through the multivariate adaptive regression splines(MARS)method.Some parameters have been estimated using the MARS method in order to use pneumatic cleaners under optimum conditions and adapt them to automation systems.The cleaners have a collection box which was installed at the outlet of the storage.Two different product collection boxes of 400 mm(defined as the first box)and 800 mm(defined as the second box)from the storage outlet section were used.From the results obtained,it was observed that the first box R2 was higher.When looking at the cross validation,it was observed that the results of the first box were more acceptable.With this study,MARS equations were used to obtain dependent variables at desired values.Using these equations,independent variables have been demonstrated to be identifiable.In the application results obtained,cleaning efficiency values were obtained in a wide range.While cleaning efficiency values reached up to 100%,the loss rate was found to be very high.Independent variables have been made identifiable to reduce the loss rate.The highest and feasible of these values were determined by MARS as 41°fan angle and 15 m/s air velocity in order to be able to apply at 97%CE and 1%LR determined for the first box.The MARS method allows for the use of more dependent and independent variables.Usable equations were obtained as a result of statistical analysis.More precise values can be obtained with these equations.It will contribute to the design of the parameters of the machine manufactured,such as speed,angle,and feeding amount.展开更多
Rare earth elements(REEs)are irreplaceable materials supporting low-carbon technology and equip-ment,and their commercial demand and strategic position are becoming increasingly prominent.With the continuous depletion...Rare earth elements(REEs)are irreplaceable materials supporting low-carbon technology and equip-ment,and their commercial demand and strategic position are becoming increasingly prominent.With the continuous depletion of rare earth(RE)resources,developing high-efficiency beneficiation and eco-friendly metallurgical processes has attracted widespread attention.This paper reviews the major minerals exploited for RE production and their deposits,as well as the beneficiation and metallurgical processes of RE minerals.Bastnaesite,monazite,mixed RE ores,and ion-adsorption clays are the main raw materials in the world to date.RE-bearing ores(except ion-adsorption minerals)are generally beneficiated by flotation,gravity and magnetic separation techniques.The mainstream metallurgical processes for bastnaesite,monazite and mixed RE concentrates are oxidation roasting-HCl leaching,caustic soda decomposition and high-temperature concentrated sulfuric acid roasting,respectively.Ion-adsorption clays are directly processed by in situ leaching-precipitation/solvent extraction.To achieve the sustainable development of RE resources,it is essential to further explore innovative techniques to achievecomprehensive utilization and cleaner production.展开更多
The clothing industry is considered one of the most polluting industries on the planet due to the high consumption of water,energy,chemicals/dyes,and high generation of solid waste and effluents.Faced with environment...The clothing industry is considered one of the most polluting industries on the planet due to the high consumption of water,energy,chemicals/dyes,and high generation of solid waste and effluents.Faced with environmental concerns,the textile ennoblement sector is the most critical of the textile production chain,especially the traditional dyeing processes.As an alternative to current problems,dyeing with supercritical CO_(2)(scCO_(2))has been presented as a clean and efficient process for a sustainable textile future.Supercritical fluid dyeing(SFD)has shown a growing interest due to its significant impact on environmental preservation and social,economic,and financial gains.The main SFD benefits include economy and reuse of non-adsorbed dyes;reduction of process time and energy expenditure;capture of atmospheric CO_(2)(greenhouse gas);use and recycling of CO_(2)in SFD;generation of carbon credits;water-free process;effluent-free process;reduction of CO_(2)emission and auxiliary chemicals.Despite being still a non-scalable and evolving technology,SFD is the future of dyeing.This review presented a comprehensive overview of the environmental impacts caused by traditional processes and confronted the advantages of SFD.The SFD technique was introduced,along with its latest advances and future perspectives.Financial and environmental gains were also discussed.展开更多
An in-process technology approach is proposed to identify the source of acid mine drainage(AMD)generation and prevent its formation in a porphyry copper waste rock(WR).Adopting actions before stockpiling the WR enable...An in-process technology approach is proposed to identify the source of acid mine drainage(AMD)generation and prevent its formation in a porphyry copper waste rock(WR).Adopting actions before stockpiling the WR enables the establishment of potential contaminants and predicts the more convenient method for AMD prevention.A WR sample was separated into size fractions,and the WR’s net acidgenerating potential was quantified using chemical and mineralogical characterization.The diameter of physical locking of sulfides(DPLS)was determined,and the fractions below the DPLS were desulfurized using flotation.Finally,the WR fractions and tailing from the flotation test were submitted to acid-base accounting and weathering tests to evaluate their acid-generating potential.Results show that the WR’s main sulfide mineral is pyrite,and the DPLS was defined as 850μm.A sulfide recovery of 91%was achieved using a combination of HydroFloat^(®)and Denver cells for a size fraction lower than DPLS.No grinding was conducted.The results show that size fractions greater than DPLS and the desulfurized WR are unlikely to produce AMD.The outcomes show that in-processing technology can be a more proactive approach and an effective tool for avoiding AMD in a porphyry copper WR.展开更多
文摘Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.
文摘In view of Chinese eating habits and the ways of cooking, this article described the principle and characteristics of kitchen greasy dirt formations, analysed the main factors influencing the performance of kitchen cleaner formulas, introduced the current situation of development of kitchen cleaners in China, analysed modern consumers＇ demand for kitchen cleaners and discussed the future development trend of kitchen cleaners.
基金This work was financially supported by the National Key R&D Plan project(Grant No.2016YFD070030201)the Jilin Science and Technology Development Plan(20160309001NY)。
文摘In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,in this study,bionic mole forelimb intelligent row cleaners comprising of a cleaning device and a depth intelligent control system were designed.Via theoretical analysis,computer-based simulation,and test optimized design,the mechanism of bionic cleaners that possessed the forelimb motion morphology and the front claw toe structural morphology of moles was studied,the effects of structural parameters of bionic cleaners on the cleaning quality were clarified.Based on a pressure sensor,a depth intelligent control system was designed,which enhanced the depth stability of the cleaning devices.The types of bionic cleaners were identified by simulation on EDEM software.Then regression equations between different parameters and operation evaluation indices were established,and the optimal parameter combination was identified on Design-Expert software with a rotation radius of 150 mm and a motion deflection angle of 15.8°,at which the cleaning rate was 91.3%.Field tests under the optimal parameter combination showed that bionic cleaners outperformed normal planar cleaners,and the depth intelligent control system could efficiently improve the performance of the row cleaners.The straw cleaning rate of the bionic mole forelimb intelligent row cleaners under total straw mulching fields was 90.9%,which was 21.3%higher than that of normal cleaners,and the ground surfaces after operation satisfied the agricultural requirements of maize no-tillage sowing.
文摘This study assessed six commercially available in-duct air cleaning devices which are designed to be mounted in the central ventilation system of offices or commercial buildings.The selected devices use different air cleaning technologies:mechanical filtration,electrostatic precipitation,gas filtration,ionization/cold plasma,photocatalytic oxidation(PCO)and catalysis under UV light.They were tested against particles,a mixture of volatile organic compounds containing acetone,acetaldehyde,toluene,heptane and formaldehyde,and two bio-contaminants:Aspergillus brasiliensis(fungus)and Staphylococcus epidermidis(bacteria).Two different test rigs were used.The single pass efficiency of each device was determined for three airflow rates,corresponding to face velocities ranging from 0.9 to 2.7 m/s,and two sets of temperature and humidity that are representative of indoor air conditions in wintertime and summertime.The concentration of the chal-lenge volatile organic compounds was also varied in the 30 to 100μg/m^(3)range as a way to characterize their influence on efficiency at realistic concentration levels for non-industrial buildings.Measurements of ozone and formaldehyde concentration downstream of the air cleaners were carried out to determine the emission rate of by-products into the air stream.Finally,the energy issue was addressed by measuring the electric power drawn and pressure loss of the devices.The results showed that two devices,namely a radiant catalytic ionizer and a plasma ionizer,had a very low single pass efficiency against all the challenge pollutants.The association of the plasma ionizer and the electrostatic precipitator did not produce a synergetic effect between the two technologies either,contrary to what their manufacturer claims.Finally,three of the six devices tested were effective in terms of pollutant removal,but only two had an acceptable energy effectiveness in view of their use in low or zero energy buildings.Their energy effectiveness ranged from a few thousand m^(3)/kWh for VOCs at the highest airflow rate(3600 m^(3)/h),to more than 60000 m^(3)/kWh for particles and bio-contaminants at 1200 or 1600 m^(3)/h.These results are at least one order of magnitude higher than the majority of stand-alone air cleaners.Moreover,they suggest that optimal IAQ and energy conditions can be achieved if variable air volume control methods are used to maintain indoor temperature and humidity.
文摘一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。A It's Sunday afternoon.Mike's family are at home.When Mike and his 4 year-old brother Bruce are__1__in their room,Dad is cleaning the living room with the cleaner(吸尘器).
基金sponsored by MCIN/AEI/10.13039/501100011033“ERDF A way of making Europe”(grant PID2021-125637OB-I00)FEDER/Junta de Andalucía Programmes(grants PY20_00751 and UHU202029).
文摘The aim of this work is to find an alternative lubricating grease formulation that can be produced from renewable and biodegradable sources with minimal risks to human health and the environment.We used a castor oil and electrospun cellulose acetate propionate(CAp)as raw materials.We hypothesized that the acetyl and propionyl groups could provide an adequate chemical compatibility with the castor oil and that the electrospun nanostructures could enable improved physical stability by creating a variety of morphologies allowing the tailoring of the rheological and tribological properties of the resulting greases.The experimental results show that the use of electrospun CAp nanostructures can indeed yield physically stable formulations,even when used at low concentrations(3 wt%).The resulting dispersions went through structural transitions due to changes in the thickener morphologies and/or concentration,as shown by oscillatory rheology,oil holding capacity,tackiness,and lubrication performance in metal–metal contact.We found that the formulations,containing smooth or porous CAp nanofibers,at 5 wt%as a thickener,possess suitable rheological and tribological properties with a performance comparable to that of traditional lithium lubricating greases.
文摘This study evaluates the Fuzzy Analytical Hierarchy Process(FAHP)as a multi-criteria decision(MCD)support tool for selecting appropriate additive manufacturing(AM)techniques that align with cleaner production and environmental sustainability.The FAHP model was validated using an example of the production of aircraft components(specifically fuselage)employing AM technologies such as Wire Arc Additive Manufacturing(WAAM),laser powder bed fusion(L-PBF),Binder Jetting(BJ),Selective Laser Sintering(SLS),and Laser Metal Deposition(LMD).The selection criteria prioritized eco-friendly manufacturing considerations,including the quality and properties of the final product(e.g.,surface finish,high strength,and corrosion resistance),service and functional requirements,weight reduction for improved energy efficiency(lightweight structures),and environmental responsibility.Sustainability metrics,such as cost-effectiveness,material efficiency,waste minimization,and environmental impact,are central to the evaluation process.A computer-aided modeling approach was also used to simulate the performance of aluminum(AA7075 T6),steel(304),and titanium alloy(Ti6Al4V)for fuselage development.The results demonstrate that MCD approaches such as FAHP can effectively guide the selection of AM technologies that meet functional and technical requirements while minimizing environmental degradation footprints.Furthermore,the aluminumalloy outperformed the other materials investigated in the simulation with the lowest stress concentration and least deformation.This study contributes to advancing cleaner production practices by providing a decision-making framework for sustainable and eco-friendly manufacturing,enabling manufacturers to adopt AM technologies that promote environmental responsibility and sustainable development,while maintaining product quality and performance.
文摘Shanxi,China’s leading coal-mining province,is feeding more green power into the national grid,heralding an era of cleaner and more sustainable energy.AT the national demonstration base of advanced photovoltaic(PV)technology in Datong City,Shangxi Province-the largest coal producer in China,rows upon rows of solar panels glitter in the sunlight,resembling a twinkling blue ocean.
基金supported by the China Postdoctoral Science Foundation (No. 2023T160088)the Youth Fund of the National Natural Science Foundation of China(No.52304324)+1 种基金the National Natural Science Foundation of China (U1908225, U1702253)the Special Funds for Basic Research Operations of Central Universities(N182515007, N170908001, N2025004)。
文摘Compared with the vacuum continuous magnesium smelting process(RVCMS), its excellent energy saving and emission reduction performance provides a feasible method for green magnesium smelting. In the process of industrialization, the reduction rate of prefabricated pellets affects the yield of metal magnesium and the utilization of reducing slag. In this paper, the reduction mechanism under different carbonate structures is analyzed by controlled disproportionation of prefabricated pellets and micro-nano simulation. The results show that the low temperature decomposition of NH_(4)·HCO_(3)pore-forming, improve the reduction rate(99.72%) effect is remarkable. Combined with thermodynamics and relative vacuum mechanism, a theoretical model of the relationship between disproportionation pore-forming and reduction rate was established. It was concluded that the energy consumption required to produce per ton of magnesium by adding NH_(4)·HCO_(3)to the prefabricated pellets was reduced by 0.29±0.34 tce, and the carbon emission was reduced by 1.069±1.263 t. The reduction slag had good compressive strength(Side 101.19 N cm^(-2), Bottom 466.4 N cm^(-2)). Compared with the 20 MPa reduction slag sample without pore-forming agent, the side compressive strength increased by 51.66%, and the bottom compressive strength increased by 119.10%. The amount of single furnace filler is increased by more than 50%.
文摘Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 exhibitors from more than 30 countries including China to address the future of cleaner and more inclusive energy.
文摘Cleaner air,lower dependency on oil,and lower emissions are just a few reasons to move away from combustion cars.In the wake of the emergence of more environmentally friendly technology,some countries have decided to move away from traditional cars towards electric vehicles (EVs).The rise of the EV industry has created a shift in energy demand from oil-based to battery-based.
基金the support the National Natural Science Foundation of China(5210440)S&T Program of Hebei(23311501D)Program of HBIS Group under HG2023222。
文摘In this study,a cleaner method for separation and recovery of V/W/Na in waste selective catalytic reduction(SCR)catalyst alkaline leaching solution was proposed.The method involved membrane electrolysis followed by ion morphology pretreatme nt and solvent extraction.An acidic V(Ⅴ)/W(Ⅵ)solution was obtained using the me mbrane electrolysis method without adding any other chemical reagents.In addition,Na was recovered in the form of NaOH by product,avoiding the generation of Na containing wastewater.The electrolysis parameters were investigated,the lowest power consumption of 3063 kW·h·t^(-1)NaOH was obtained at a current density of 125 A·m^(-2)and an initial NaOH concentration of 2 mol·L^(-1).After electrolysis,oxalic acid was added to the acidic V/W containing solution,converting V(Ⅴ)negative ion to V(Ⅳ)positive ion.Since W(Ⅵ)ion state remained in negative form,the generation of heteropolyacid ions(W_(x)V_(y)O_(z)^(n-))was prevented.It was found that under the condition of oxalic acid addition/theoretical consumption 1.2 and reaction temperature 75℃,100%V(Ⅴ)was co nverted to V(Ⅳ4).Using 10%N263+10%noctanol+80%sulfonated kerosene as extractant,the highest W(Ⅵ)/V(Ⅳ)separation coefficient of 7559.76was obtained at pH=1.8,O:A ratio=1:1 and extraction time 15 min.With 2 mol·L^(-1)NaOH as stripping reagent,the W stripping efficiency reached 98.50%at O:A ratio=2:1 after 4-stages of stripping.The enrichment of V remained in the solution was realized using P204 as extractant and 20%(mass)H_(2)SO_(4)as stripping reagent.The parameters of extraction/stripping process were investigated,using 10%P204+10%TBP+80%sulfonated kerosene as extractant,the V extraction efficiency reached 97.50%at O:A ratio=1:2after 4 stages of extraction.Using 20%H_(2)SO_(4)as the stripping reagent,the V stripping efficiency was 98.30%at an O:A ratio of 4:1 after five stage s of stripping.After the entire process,a high-purity VOSO_(4)and Na_(2)WO_(4)product solutions were obtained with V/W recovery efficiency 95.84%/98.50%,separately.This study examined a more effective and cleaner method for separating V/W/Na in Na_(2)WO_(4)/NaVO_(3)solution,which may serve as a reference for the separation and recovery of V/W/Na in waste SCR catalysts.
文摘Entreprencurship is not something that springs to mind when people think of China.Just a few decides ago being an entrepreneur or small business owner was practically a criminal offense in some areas ol’the country.But,somehow,over the past few years,China has grown into a startup superpower.’’Startup Kingdom'(see page 28)looks at how the Middle Kingdom came to be one of the most exciting startup markets in the world and some of the
基金This study was supported by the National Science and Technology Research Program(2013BAD08B01-3)the Soil-Machine-Plant Key Laboratory of Ministry of Agriculture of PR China.
文摘In the continuous annual wheat-corn cropping area of North China Plain,no-till planting that promotes soil conservation and crop yield while reducing operation cost has been gradually accepted by local farmers.However,previous wheat residue is the main limiting factor affecting the performance of existing planters in placing seeds at uniform spacing and optimum depth in residue covered fields.In order to solve this problem,a kind of ground-wheel-driven row cleaner was designed,developed and mounted on row units of a four-row pneumatic precision planter.The planter has two adjacent row units equipped with the newly designed row cleaners and the other two adjacent row units equipped with the commonly used inactive row cleaners.This was used for planting at three forward speeds(4 km/h,6 km/h and 8 km/h)into half residue(HR)and whole residue(WR)plots.The amount of residue removal,seeding depth,emergence rate and indices of uniformity in seed spacing(missing-seeding index,quality of feeding index and precision index)were measured.The newly designed row cleaner performed better with regard to residue removal,with the average percentage of residue cleared as 63.0%compared to 40.3%for the inactive row cleaner.For the HR and WR plots,percentage of residue cleared of the newly designed row cleaner reached 57.1%and 68.9%respectively,suggesting that the newly designed row cleaner can work more effectively at high residue level.By contrast,with the percentage of residue cleared of the inactive row cleaner as 43.1%and 37.5%in HR and WR plots,suggesting that the inactive row cleaner just can work effectively under low residue condition.Values of missing-seeding index,QFI,precision index,coefficient of variation of depth and percent emergence for the newly designed row cleaner under whole residue level are comparable to those for the inactive row cleaner under half residue level.The result indicates that the effect of using the newly designed row cleaner is equal to that of reducing surface residue,and can help to maintain the uniformity of seed spacing and seeding depth.The newly designed row cleaner generally performed better at forward speed of 6 km/h,based on the distribution of seeds along rows and seeding depth uniformity.
基金This study was jointly funded by the National Key Research and Development Program of China(No.2016YFC0700500)the Opening Fund of Key Laboratory of Plateau Green Building and Ecological Community in Qinghai Province(No.KLKF-2020-005).
文摘Natural ventilation(NV)has been considered a simple and effective method of ventilation.However,the intro-duction of NV does not achieve better indoor air quality(IAQ)when the outdoor atmospheric environment is polluted.Therefore,portable air cleaners(PACs)are increasing in use in recent years,but their effectiveness is highly dependent on the residents’habits.A typical residence in Xi’an,China was selected to examine the effects of the use of NV alone and the use of NV and PACs together on IAQ in the three occupant states,i.e.,unoc-cupied,sleeping and leisure.Parameters,such as temperature,relative humidity,CO_(2),and PM_(2.5)concentration were measured when changing the window opening and the position of the PAC.The results showed that in the unoccupied state,opening the inner door can promote a more uniform thermal and humid environment.In the sleeping state,the I/O ratio of the PM_(2.5)concentration was the lowest when the window opening of the bedroom was 1/2 or 3/4,with a mean value of 0.3.In the leisure state,only using NV,when the purification rate reaches 90%,the mean purification time of each window opening in the living room is 87.5 min.The mean purification time was reduced to 25 min when both NV and PAC were used.The on-site purification efficiencies were 91.0%and 94.5%,when the window opening was 1/2(i.e.,the PAC was placed in the center of the room)and 3/4(i.e.,the PAC was placed away from the outer window),respectively.
文摘One of the cleaning methods for agricultural materials is based on aerodynamic properties.Pneumatic cleaners are developed on this method.The purpose of this study is to predict the parameters such as fan angle,air velocity,and tunnel length,which are used in the design of pneumatic cleaners,through the multivariate adaptive regression splines(MARS)method.Some parameters have been estimated using the MARS method in order to use pneumatic cleaners under optimum conditions and adapt them to automation systems.The cleaners have a collection box which was installed at the outlet of the storage.Two different product collection boxes of 400 mm(defined as the first box)and 800 mm(defined as the second box)from the storage outlet section were used.From the results obtained,it was observed that the first box R2 was higher.When looking at the cross validation,it was observed that the results of the first box were more acceptable.With this study,MARS equations were used to obtain dependent variables at desired values.Using these equations,independent variables have been demonstrated to be identifiable.In the application results obtained,cleaning efficiency values were obtained in a wide range.While cleaning efficiency values reached up to 100%,the loss rate was found to be very high.Independent variables have been made identifiable to reduce the loss rate.The highest and feasible of these values were determined by MARS as 41°fan angle and 15 m/s air velocity in order to be able to apply at 97%CE and 1%LR determined for the first box.The MARS method allows for the use of more dependent and independent variables.Usable equations were obtained as a result of statistical analysis.More precise values can be obtained with these equations.It will contribute to the design of the parameters of the machine manufactured,such as speed,angle,and feeding amount.
基金Project supported by the National Key R&D Program of China(2022YFC2905800,2021YFC2901000)the National Natural Science Foundation of China(52174242,52130406).
文摘Rare earth elements(REEs)are irreplaceable materials supporting low-carbon technology and equip-ment,and their commercial demand and strategic position are becoming increasingly prominent.With the continuous depletion of rare earth(RE)resources,developing high-efficiency beneficiation and eco-friendly metallurgical processes has attracted widespread attention.This paper reviews the major minerals exploited for RE production and their deposits,as well as the beneficiation and metallurgical processes of RE minerals.Bastnaesite,monazite,mixed RE ores,and ion-adsorption clays are the main raw materials in the world to date.RE-bearing ores(except ion-adsorption minerals)are generally beneficiated by flotation,gravity and magnetic separation techniques.The mainstream metallurgical processes for bastnaesite,monazite and mixed RE concentrates are oxidation roasting-HCl leaching,caustic soda decomposition and high-temperature concentrated sulfuric acid roasting,respectively.Ion-adsorption clays are directly processed by in situ leaching-precipitation/solvent extraction.To achieve the sustainable development of RE resources,it is essential to further explore innovative techniques to achievecomprehensive utilization and cleaner production.
文摘The clothing industry is considered one of the most polluting industries on the planet due to the high consumption of water,energy,chemicals/dyes,and high generation of solid waste and effluents.Faced with environmental concerns,the textile ennoblement sector is the most critical of the textile production chain,especially the traditional dyeing processes.As an alternative to current problems,dyeing with supercritical CO_(2)(scCO_(2))has been presented as a clean and efficient process for a sustainable textile future.Supercritical fluid dyeing(SFD)has shown a growing interest due to its significant impact on environmental preservation and social,economic,and financial gains.The main SFD benefits include economy and reuse of non-adsorbed dyes;reduction of process time and energy expenditure;capture of atmospheric CO_(2)(greenhouse gas);use and recycling of CO_(2)in SFD;generation of carbon credits;water-free process;effluent-free process;reduction of CO_(2)emission and auxiliary chemicals.Despite being still a non-scalable and evolving technology,SFD is the future of dyeing.This review presented a comprehensive overview of the environmental impacts caused by traditional processes and confronted the advantages of SFD.The SFD technique was introduced,along with its latest advances and future perspectives.Financial and environmental gains were also discussed.
基金supported by Agencia Nacional de Investigación y Desarrollo de Chile(ANID)Anillo-Grant ANID/ACT210027,Fondecyt 1211498,and ANID/AFB230001+1 种基金the ANID scholarship Grant 21210801partially performed by Luis Cisternas during the visit to the Universitédu Québec,supported by MINEDUC-UA project,code ANT1999.
文摘An in-process technology approach is proposed to identify the source of acid mine drainage(AMD)generation and prevent its formation in a porphyry copper waste rock(WR).Adopting actions before stockpiling the WR enables the establishment of potential contaminants and predicts the more convenient method for AMD prevention.A WR sample was separated into size fractions,and the WR’s net acidgenerating potential was quantified using chemical and mineralogical characterization.The diameter of physical locking of sulfides(DPLS)was determined,and the fractions below the DPLS were desulfurized using flotation.Finally,the WR fractions and tailing from the flotation test were submitted to acid-base accounting and weathering tests to evaluate their acid-generating potential.Results show that the WR’s main sulfide mineral is pyrite,and the DPLS was defined as 850μm.A sulfide recovery of 91%was achieved using a combination of HydroFloat^(®)and Denver cells for a size fraction lower than DPLS.No grinding was conducted.The results show that size fractions greater than DPLS and the desulfurized WR are unlikely to produce AMD.The outcomes show that in-processing technology can be a more proactive approach and an effective tool for avoiding AMD in a porphyry copper WR.
