Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiay...Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiayuan—New Countryside Distripark CDM project in Wuchuan County was taken as an example for developing an interval linear programming (ILP) model to optimize the crops planting scheme and cows breeding scheme by using interval optimal method. The case showed that the optimized crops planting scheme and cows breeding scheme obtained from the optimal model was reasonable with relatively preferable overall performance. In the context of meeting economic benefits and fertilizer, electricity demand, [231 287.8, 273 312.7] t of CO2 could be absorbed and fixed, which had increased by [12.94, 33.46]% compared with the feasibility scheme of case project and provided technical support for making the decision in CDM project.展开更多
The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9O...The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions (Nt/m), molar ratio of ammonia to La and Zr metal ions (Na/m), hydrothermal temperature (Thydro), and hy‐drothermal time (thydro). The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42?/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42?/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42?/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.展开更多
Since the production cost of biodiesel is now the main hurdle limiting their applicability in some areas, catalytic cracking reactions represent an alternative route to utilization of vegetable oils and animal fats. H...Since the production cost of biodiesel is now the main hurdle limiting their applicability in some areas, catalytic cracking reactions represent an alternative route to utilization of vegetable oils and animal fats. Hence, catalytic transformation of oils and fats was carried out in a laboratory-scale two-stage riser fluid catalytic cracking (TSRFCC) unit in this work. The results show that oils and fats can be used as FCC feed singly or co-feeding with vacuum gas oil (VGO), which can give high yield (by mass)of liquefied petroleum gas (LPG), C2-C4 oletms, tor example 45% LPG, 47% C2-C4 olefins, and 77.6% total liquid yield produced with palm oil cracking. Co-feeding with VGO gives a high yield of LPG (39.1%) and propylene (18.1%). And oxygen element content is very low (about 0.5%) in liquid products, hence, oxygen is removed in the form of H2O, CO and CO2. At the same time, high concentration of aromatics (C7-C9 aromatics predominantly) in the gasoline fraction is obtained after TSRFCC reaction of palm oil, as a result of large amount of hydrogen-transfer, cyclization and aromatization reactions, Additionally, most of properties of produced gasoline and diesel oil fuel meet the requirements of national standards, containing little sulfur. So TSRFCC technology is thought to be an alternative processing technology leading to production of clean fuels and light olefins.展开更多
The experimental study was carried out to optimize the nozzle shape and dimension for the pulse cleaning of a ceramic filter candle. A bench scale unit of ceramic filter consisting of four commercial filter elements w...The experimental study was carried out to optimize the nozzle shape and dimension for the pulse cleaning of a ceramic filter candle. A bench scale unit of ceramic filter consisting of four commercial filter elements was used to measure the traces of the transient pressure around the nozzle and the overpressure in the filter cavity during the pulse-jet injection of pulse gas. Overpressure in the filter cavity is related to the pulse cleaning force. Nozzle design is concerned to increase the overpressure at the open end of filter element of pulse cleaning inlet, as well as to minimize the consumption of pulse gas. Convergent nozzle induces more secondary flow and generates higher pulse cleaning effect than straight nozzle. Nozzles of different convergent ratio (ratio of outlet to inlet diameter of nozzle) by changing the convergent angle and height were tested. The outlet diameter of convergent nozzle seriously influences the cleaning effect. The optimum convergent ratio increases with the increase of pulse gas pressure The nozzle position (distance of nozzle tip from the open end of filter inlet) is also important to decide the nozzle dimension. Nozzle of large outlet diameter accepts high pressure of pulse gas to provide large overpressure in the filter cavity of top position by applying long distance.展开更多
A superhydrophobic Zn−Fe alloy coating was prepared on the surface of a reactive magnesium alloy using a simple,low-cost,eco-friendly method.Firstly,the Zn−Fe coating was obtained in a neutral glycerol Zn−Fe plating s...A superhydrophobic Zn−Fe alloy coating was prepared on the surface of a reactive magnesium alloy using a simple,low-cost,eco-friendly method.Firstly,the Zn−Fe coating was obtained in a neutral glycerol Zn−Fe plating solution,which is green,compositionally stable,and non-corrosive to the equipment.And then the superhydrophobic surface with a flower-like microstructure was obtained by grafting myristic acid onto the Zn−Fe coating via a chelation reaction.The water contact angle was>150°and the rolling angle was 3°−4°.The corrosion rate of the two groups of superhydrophobic magnesium alloy samples with electrodeposition time of 30 and 50 min,respectively,was reduced by about 87%compared to that of the bare magnesium alloy.The prepared superhydrophobic coatings exhibit high performance in self-cleaning,abrasion resistance,and corrosion resistance.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
A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite ...A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite catalysts for alkenylation of p‐xylene with phenylacetylene was investigated.Various characterization techniques,including X‐ray diffraction,X‐ray fluorescence,nitrogen adsorption‐desorption,and NH3temperature‐programmed desorption,were used to examine the structure‐performance relationships.Our results show that the optimized ceria‐modified hierarchical Hβzeolite catalyst demonstrated higher catalytic activity,selectivity,and stability for alkenylation of p‐xylene with phenylacetylene than those of pristine Hβzeolite.This performance was attributed to more acidic sites and improved accessibility to active sites through larger pores,together with a higher mesoporous surface area and volume resulting from the hierarchical pore architecture and ceria modification.Thus,our5wt%CeO2‐Hβ‐B0.2A0.2catalyst shows great potential for producing alkenyl aromatics through solid acid catalyzed alkenylation.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved展开更多
This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization...This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization of process conditions, selection of equipment, and experiment of recycle of waste acid are carried out. The process design is realized in consideration of several aspects such as operation, material, equipment design and safety. An industrialized process flowsheet is developed according to experiment. A pilot testing is carried out to confirm the lab results. Process design of chlorine dioxide production based on hydrogen peroxide is realized.展开更多
Coal is the dominant primary energy source in China and the major source of greenhouse gases and air pollutants. To facilitate the use of coal in an environmentally satisfactory and economically viable way, clean coal...Coal is the dominant primary energy source in China and the major source of greenhouse gases and air pollutants. To facilitate the use of coal in an environmentally satisfactory and economically viable way, clean coal technologies (CCTs) are necessary. This paper presents a review of recent research and development of four kinds of CCTs: coal power generation; coal conversion; pollution control; and carbon capture, utilization, and storage. It also outlines future perspectives on directions for technology re search and development (R&D). This review shows that China has made remarkable progress in the R&D of CCTs, and that a number of CCTs have now entered into the commercialization stage.展开更多
The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. ...The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. Moreover, fuel consumption and the work intensity of divers will be reduced. In this paper, the current situation and the latest technology in China and abroad were analyzed;meanwhile, the typical characteristics of the underwater cleaning robot were introduced. According to the work principle of the underwater cleaning robot, the emphasis was put on the analysis and study of permanent-magnetic absorption, magnetic wheel, airproof and anticorrosion, underwater cleaning equipment and control system. The robot is easy in rotation and simple in control.展开更多
As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natura...As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifier by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore, the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.展开更多
To investigated characteristics, diagnosis, bowel-cleansing preparation, sedation, and colonoscope length and diameter in Japanese pediatric patients receiving total colonoscopy. METHODSThe present study evaluated con...To investigated characteristics, diagnosis, bowel-cleansing preparation, sedation, and colonoscope length and diameter in Japanese pediatric patients receiving total colonoscopy. METHODSThe present study evaluated consecutive patients aged ≤ 15 years who had undergone their first colonoscopy in Kurume University between January 2007 and February 2015. Data were retrospectively analyzed. We identified 110 pediatric patients who had undergone colonoscopy that had reached the cecum, allowing the observation of the total colon. RESULTSHematochezia, abdominal pain, and diarrhea were the most common symptoms. For bowel-cleansing preparation, pediatric patients aged ≤ 12 years were treated with magnesium citrate, and patients aged 13-15 years were treated with polyethylene glycol 4000. For sedation, thiamylal with pentazocine, which has an analgesic effect, was used in patients aged ≤ 6 years, and midazolam with pentazocine was used in patients aged ≥ 7 years. Regarding the choice of endoscope, short and thin endoscopes were selected for younger patients, particularly patients aged ≤ 3 years. Positive diagnoses were made in 78 patients (70.9%). Inflammatory bowel disease (n = 49, 44.5%), including ulcerative colitis (n = 37, 33.6%) and Crohn’s disease (n = 12, 10.9%), was the most common diagnosis. CONCLUSIONColonoscopy offers a high diagnostic capability for pediatric patients with gastrointestinal symptoms. The selection of appropriate management the performance of colonoscopy is important in pediatric patients.展开更多
Environmental concerns have highlighted the need of cleaner technologies. A cleaner, convenient and selective technology has been developed for the preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol (...Environmental concerns have highlighted the need of cleaner technologies. A cleaner, convenient and selective technology has been developed for the preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol (DPMP) from 2-methyl-benzene-1,3-diol in water as solvent. The isolated yield of DPMP is up to 86% in good selectivity. The product structure was characterized by conventional methods, H-NMR and MS. This technology belongs to the modern concept of 1 environmentally friendly low wastes or non-wastes technology (LWNWT).展开更多
More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. Howeve...More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.展开更多
Introduced a new gravity and flotation separator with double-tailing dtsctaarge tor nne coat~, u,u ,,,~,.~ cation and cyclone scavenging with flotation in an original way. The beneficiation performance of it was good....Introduced a new gravity and flotation separator with double-tailing dtsctaarge tor nne coat~, u,u ,,,~,.~ cation and cyclone scavenging with flotation in an original way. The beneficiation performance of it was good. The results show that the gravity and flotation separator with double-tailing discharge can produce high-quality clean coal of 10.46% ash from free coal of 35.56% ash. It can discharge the fine and coarse tailings separately.展开更多
Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the ...Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.展开更多
A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain p...A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.展开更多
A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray di...A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray diffraction,energydispersive X-ray spectroscopy,and Fourier-transform infrared spectroscopy were employed to investigate the morphology and chemical composition.The results showed that the SAP surface had three-dimensional micro-nano structures and exhibited a maximum water contact angle of 160.0°,oil contact angle of 151.6°,a minimum water slide angle of 0°and oil slide angle of 9°.The mechanical strength and chemical stability of the SAP surface were tested further.The experimental results showed that the SAP surface presented excellent resistance to wear,prominent acid-resistance and alkali-resistance,self-cleaning and anti-fouling properties.展开更多
A detailed mechanism analysis of cellulose pyrolysis was carried out according to the previous experimental results. On the basis of the Brodio-Shafizadeh model, a modified two-stage model was proposed to simulate the...A detailed mechanism analysis of cellulose pyrolysis was carried out according to the previous experimental results. On the basis of the Brodio-Shafizadeh model, a modified two-stage model was proposed to simulate the formation and decomposition of active cellulose (AC) and several main organic compounds, such as levoglucosan (LG), hydroxyl-acetaldehyde (HAA), acetol and furfural etc. During pryolysis, the temperature rise of cellulose can be divided into three stages. In the second stage, cellulose undergoes a main decomposition process in which the reaction temperature remains rather low because of the endothermic cracking of glucosidic bond of AC during the formation of LG. The components density of bio-oil, including LG and other competitive compounds, increased rapidly with the increase of temperature during the first stage. However, in the main decomposition process, LG density in bio-oil had an obvious decrease, while the competitive products appeared to increase gradually, which means the ring-opening and reforming reaction of pyranoid ring are superior to LG formation in high temperature.The secondary reaction of volatile components occurs largely in gaseous phase rather than in the solid phase. Short residence time of volatile materials in high temperature region will be advantageous to a high production of LG,which may otherwise decompose quickly under high temperature. An optimum yield of LG could be obtained when radiant source temperature is in the range of 730---920K and gas residence time is less than 1 s. In addition, the reaction temperature has a stronger effect than gas residence time on the formation of HAA, acetol, formaldehyde and furfural etc.展开更多
文摘Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiayuan—New Countryside Distripark CDM project in Wuchuan County was taken as an example for developing an interval linear programming (ILP) model to optimize the crops planting scheme and cows breeding scheme by using interval optimal method. The case showed that the optimized crops planting scheme and cows breeding scheme obtained from the optimal model was reasonable with relatively preferable overall performance. In the context of meeting economic benefits and fertilizer, electricity demand, [231 287.8, 273 312.7] t of CO2 could be absorbed and fixed, which had increased by [12.94, 33.46]% compared with the feasibility scheme of case project and provided technical support for making the decision in CDM project.
基金financially supported by the National Natural Science Foundation of China (21276041)the Program for New Century Excellent Talents in University of Ministry of Education (NCET-12-0079)+1 种基金the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)~~
文摘The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids (SO42?/meso‐La0.1Zr0.9Oδ) were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions (Nt/m), molar ratio of ammonia to La and Zr metal ions (Na/m), hydrothermal temperature (Thydro), and hy‐drothermal time (thydro). The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42?/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42?/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42?/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.
基金the Major Research Plan of PetroChina Company Limited (07-03D-01-01-02-02)
文摘Since the production cost of biodiesel is now the main hurdle limiting their applicability in some areas, catalytic cracking reactions represent an alternative route to utilization of vegetable oils and animal fats. Hence, catalytic transformation of oils and fats was carried out in a laboratory-scale two-stage riser fluid catalytic cracking (TSRFCC) unit in this work. The results show that oils and fats can be used as FCC feed singly or co-feeding with vacuum gas oil (VGO), which can give high yield (by mass)of liquefied petroleum gas (LPG), C2-C4 oletms, tor example 45% LPG, 47% C2-C4 olefins, and 77.6% total liquid yield produced with palm oil cracking. Co-feeding with VGO gives a high yield of LPG (39.1%) and propylene (18.1%). And oxygen element content is very low (about 0.5%) in liquid products, hence, oxygen is removed in the form of H2O, CO and CO2. At the same time, high concentration of aromatics (C7-C9 aromatics predominantly) in the gasoline fraction is obtained after TSRFCC reaction of palm oil, as a result of large amount of hydrogen-transfer, cyclization and aromatization reactions, Additionally, most of properties of produced gasoline and diesel oil fuel meet the requirements of national standards, containing little sulfur. So TSRFCC technology is thought to be an alternative processing technology leading to production of clean fuels and light olefins.
基金Supported by the National Natural Science Foundation of China (50411140527) and Korea Science and Engineering Foundation.
文摘The experimental study was carried out to optimize the nozzle shape and dimension for the pulse cleaning of a ceramic filter candle. A bench scale unit of ceramic filter consisting of four commercial filter elements was used to measure the traces of the transient pressure around the nozzle and the overpressure in the filter cavity during the pulse-jet injection of pulse gas. Overpressure in the filter cavity is related to the pulse cleaning force. Nozzle design is concerned to increase the overpressure at the open end of filter element of pulse cleaning inlet, as well as to minimize the consumption of pulse gas. Convergent nozzle induces more secondary flow and generates higher pulse cleaning effect than straight nozzle. Nozzles of different convergent ratio (ratio of outlet to inlet diameter of nozzle) by changing the convergent angle and height were tested. The outlet diameter of convergent nozzle seriously influences the cleaning effect. The optimum convergent ratio increases with the increase of pulse gas pressure The nozzle position (distance of nozzle tip from the open end of filter inlet) is also important to decide the nozzle dimension. Nozzle of large outlet diameter accepts high pressure of pulse gas to provide large overpressure in the filter cavity of top position by applying long distance.
基金supports from the National Natural Science Foundation of China(No.22178242).
文摘A superhydrophobic Zn−Fe alloy coating was prepared on the surface of a reactive magnesium alloy using a simple,low-cost,eco-friendly method.Firstly,the Zn−Fe coating was obtained in a neutral glycerol Zn−Fe plating solution,which is green,compositionally stable,and non-corrosive to the equipment.And then the superhydrophobic surface with a flower-like microstructure was obtained by grafting myristic acid onto the Zn−Fe coating via a chelation reaction.The water contact angle was>150°and the rolling angle was 3°−4°.The corrosion rate of the two groups of superhydrophobic magnesium alloy samples with electrodeposition time of 30 and 50 min,respectively,was reduced by about 87%compared to that of the bare magnesium alloy.The prepared superhydrophobic coatings exhibit high performance in self-cleaning,abrasion resistance,and corrosion resistance.
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supported by the National Natural Science Foundation of China(21276041,U1610104)the Chinese Ministry of Education via the Program for New Century Excellent Talents in University(NCET-12-0079)~~
文摘A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite catalysts for alkenylation of p‐xylene with phenylacetylene was investigated.Various characterization techniques,including X‐ray diffraction,X‐ray fluorescence,nitrogen adsorption‐desorption,and NH3temperature‐programmed desorption,were used to examine the structure‐performance relationships.Our results show that the optimized ceria‐modified hierarchical Hβzeolite catalyst demonstrated higher catalytic activity,selectivity,and stability for alkenylation of p‐xylene with phenylacetylene than those of pristine Hβzeolite.This performance was attributed to more acidic sites and improved accessibility to active sites through larger pores,together with a higher mesoporous surface area and volume resulting from the hierarchical pore architecture and ceria modification.Thus,our5wt%CeO2‐Hβ‐B0.2A0.2catalyst shows great potential for producing alkenyl aromatics through solid acid catalyzed alkenylation.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved
基金Supported by the Excellent Young Scientist Award of NSFC (20225620) the National Natural Science Foundation of China (No. 20376025) the Ministry of Education of China, the Bureau of Education of Guangdong Province.
文摘This paper presents a process development and design of chlorine dioxide production based on hydrogen peroxide. The process is characterized by cleaner production, high efficiency, and waste minimization. Optimization of process conditions, selection of equipment, and experiment of recycle of waste acid are carried out. The process design is realized in consideration of several aspects such as operation, material, equipment design and safety. An industrialized process flowsheet is developed according to experiment. A pilot testing is carried out to confirm the lab results. Process design of chlorine dioxide production based on hydrogen peroxide is realized.
基金Acknowledgements The authors gratefully acknowledge the funding support from the National Key Basic Research Program of China (2013CB228500), the National Natural Science Foundation of Chi- na (71203119), and the Advanced Coal Technology Consortium of CERC (2016YFE0102500).
文摘Coal is the dominant primary energy source in China and the major source of greenhouse gases and air pollutants. To facilitate the use of coal in an environmentally satisfactory and economically viable way, clean coal technologies (CCTs) are necessary. This paper presents a review of recent research and development of four kinds of CCTs: coal power generation; coal conversion; pollution control; and carbon capture, utilization, and storage. It also outlines future perspectives on directions for technology re search and development (R&D). This review shows that China has made remarkable progress in the R&D of CCTs, and that a number of CCTs have now entered into the commercialization stage.
基金Key Project funded by Department of Science & Technology of Heilongjiang Province (GB03A507)
文摘The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. Moreover, fuel consumption and the work intensity of divers will be reduced. In this paper, the current situation and the latest technology in China and abroad were analyzed;meanwhile, the typical characteristics of the underwater cleaning robot were introduced. According to the work principle of the underwater cleaning robot, the emphasis was put on the analysis and study of permanent-magnetic absorption, magnetic wheel, airproof and anticorrosion, underwater cleaning equipment and control system. The robot is easy in rotation and simple in control.
文摘As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, co gasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifier by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore, the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.
文摘To investigated characteristics, diagnosis, bowel-cleansing preparation, sedation, and colonoscope length and diameter in Japanese pediatric patients receiving total colonoscopy. METHODSThe present study evaluated consecutive patients aged ≤ 15 years who had undergone their first colonoscopy in Kurume University between January 2007 and February 2015. Data were retrospectively analyzed. We identified 110 pediatric patients who had undergone colonoscopy that had reached the cecum, allowing the observation of the total colon. RESULTSHematochezia, abdominal pain, and diarrhea were the most common symptoms. For bowel-cleansing preparation, pediatric patients aged ≤ 12 years were treated with magnesium citrate, and patients aged 13-15 years were treated with polyethylene glycol 4000. For sedation, thiamylal with pentazocine, which has an analgesic effect, was used in patients aged ≤ 6 years, and midazolam with pentazocine was used in patients aged ≥ 7 years. Regarding the choice of endoscope, short and thin endoscopes were selected for younger patients, particularly patients aged ≤ 3 years. Positive diagnoses were made in 78 patients (70.9%). Inflammatory bowel disease (n = 49, 44.5%), including ulcerative colitis (n = 37, 33.6%) and Crohn’s disease (n = 12, 10.9%), was the most common diagnosis. CONCLUSIONColonoscopy offers a high diagnostic capability for pediatric patients with gastrointestinal symptoms. The selection of appropriate management the performance of colonoscopy is important in pediatric patients.
文摘Environmental concerns have highlighted the need of cleaner technologies. A cleaner, convenient and selective technology has been developed for the preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol (DPMP) from 2-methyl-benzene-1,3-diol in water as solvent. The isolated yield of DPMP is up to 86% in good selectivity. The product structure was characterized by conventional methods, H-NMR and MS. This technology belongs to the modern concept of 1 environmentally friendly low wastes or non-wastes technology (LWNWT).
文摘More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.
基金Supported by the Natural Science Foundation of China (50974094) the National High-tech R & D Program of China (863 Program) (2007AA05Z317)
文摘Introduced a new gravity and flotation separator with double-tailing dtsctaarge tor nne coat~, u,u ,,,~,.~ cation and cyclone scavenging with flotation in an original way. The beneficiation performance of it was good. The results show that the gravity and flotation separator with double-tailing discharge can produce high-quality clean coal of 10.46% ash from free coal of 35.56% ash. It can discharge the fine and coarse tailings separately.
基金Supported by the National Natural Science Foundation of China (No. 50376042)Doctoral Program Foundation of Institute of Higher Education of China (20040425007).
文摘Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.
文摘A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.
基金supported by Science and Technology Department of Sichuan Province(2017JZ0021,2017SZ0039)Education Department of Sichuan Province(17ZA0298)Innovative Training Program for College Students of Sichuan Province(No.201810626118)。
文摘A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray diffraction,energydispersive X-ray spectroscopy,and Fourier-transform infrared spectroscopy were employed to investigate the morphology and chemical composition.The results showed that the SAP surface had three-dimensional micro-nano structures and exhibited a maximum water contact angle of 160.0°,oil contact angle of 151.6°,a minimum water slide angle of 0°and oil slide angle of 9°.The mechanical strength and chemical stability of the SAP surface were tested further.The experimental results showed that the SAP surface presented excellent resistance to wear,prominent acid-resistance and alkali-resistance,self-cleaning and anti-fouling properties.
基金Supported by the National Natural Science Foundation of China (No. 50176046)Guangdong Government Natural Science Foundation (No. 003045)The experiments in the paper were finished in Zhejiang University.
文摘A detailed mechanism analysis of cellulose pyrolysis was carried out according to the previous experimental results. On the basis of the Brodio-Shafizadeh model, a modified two-stage model was proposed to simulate the formation and decomposition of active cellulose (AC) and several main organic compounds, such as levoglucosan (LG), hydroxyl-acetaldehyde (HAA), acetol and furfural etc. During pryolysis, the temperature rise of cellulose can be divided into three stages. In the second stage, cellulose undergoes a main decomposition process in which the reaction temperature remains rather low because of the endothermic cracking of glucosidic bond of AC during the formation of LG. The components density of bio-oil, including LG and other competitive compounds, increased rapidly with the increase of temperature during the first stage. However, in the main decomposition process, LG density in bio-oil had an obvious decrease, while the competitive products appeared to increase gradually, which means the ring-opening and reforming reaction of pyranoid ring are superior to LG formation in high temperature.The secondary reaction of volatile components occurs largely in gaseous phase rather than in the solid phase. Short residence time of volatile materials in high temperature region will be advantageous to a high production of LG,which may otherwise decompose quickly under high temperature. An optimum yield of LG could be obtained when radiant source temperature is in the range of 730---920K and gas residence time is less than 1 s. In addition, the reaction temperature has a stronger effect than gas residence time on the formation of HAA, acetol, formaldehyde and furfural etc.