Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten ...Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten steel were investigated through steel casting tests.The results show that on the basis of surviving the thermal shock of molten steel,both filters can significantly reduce the number of non-metallic inclusions and total oxygen content of steel,thereby improving the cleanliness of the molten steel.After the thermal shock of molten steel,cracks were found in the microstructure of pure magnesia filter.Via the diffusion of non-metallic inclusions from steel into MgO grains of the filter to form solid solution,the inclusions were adsorbed to the internal and external surfaces of the pure magnesia filter.The number of inclusions was reduced by 62.5%,and the total oxygen content decreased from 0.892 to 0.265 wt.%after filtration,achieving a filtration efficiency of 70.3%.Compared with the pure magnesia filter,no cracks were found in the microstructure of the periclase-spinel filter.The mass transfer rate was accelerated due to the diffusion of inclusions from steel into MgO and MgAl2O4 grains of the filter,as well as the higher high-temperature liquid content and smaller pore structure of the filter.More non-metallic inclusions were able to enter the interior of the filter,which made the periclase-spinel filter more capable of adsorbing inclusions from steel and reducing total oxygen content.The periclase-spinel filter reduced the number of inclusions in steel by 84.4%and decreased the total oxygen content of the steel from 0.892 to 0.119 wt.%,with a filtration efficiency of 86.7%,demonstrating excellent comprehensive performance.展开更多
Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid was...Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid waste green synthesis characteristics.However,traditional manufacturing processes face challenges in pore structure control for mullite ceramics and obtaining desirable mechanical properties,which limits their application.Recently,ceramic 3D-printing technology has emerged as a research hotspot,and its effectiveness for manufacturing complex 3D porous ceramic structures and controlling their mechanical properties has been demonstrated.This paper provides a detailed overview of the precursor system and toughening mechanisms of mullite,3D-printing technology for mullite ceramics,3D porous structure design for filters,and the melt purification mechanisms of these filters.The objective of this study was to use 3D-printing technology to efficiently manufacture mullite ceramic filter elements with customized structures,controllable pore characteristics,and desirable mechanical properties.展开更多
Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of s...Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of steady filtration for wall-flow diesel particulate filter were developed and verified by experiments as well as numerically solved. Furthermore, the effects of the macroand micro-structural parameters of filtering wall and exhaust-flow characteristic parameters on trapping efficiency were also analyzed and researched. The results show that: 1) The two developed mathematical models are consistent with the prediction of variation of particulate size; the influence of various factors on the steady trapping efficiency is exactly the same. Compared to model 2, model 1 is more suitable for describing the steady filtration process of wall-flow diesel particulate filter; 2)The major influencing factors on steady trapping efficiency of wall-flow diesel particulate filter are the macro-and micro-structural parameters of filtering wall; and the secondary influencing factors are the exhaust-flow characteristic parameters and macro-structural parameters of filter; 3)The steady trapping efficiency will be improved by increasing filter body volume, pore density as well as wall thickness and by decreasing exhaust-flow, but effects will be weakened when particulate size exceeds a certain critical value; 4) The steady trapping efficiency will be significantly improved by increasing exhaust-flow temperature and filtering wall thickness, but effects will be also weakened when particulate size exceeds a certain critical value; 5) The steady trapping efficiency will approximately linearly increase with reducing porosity, micropore aperture and pore width.展开更多
This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（C...This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（CDPF）. Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number（SPN） was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration.展开更多
Circulating tumor cells （CTCs） arise from primary or secondary tumors and enter the bloodstream by active or passive intravasation. Given the low number of CTCs, enrichment is necessary for detection. Filtration met...Circulating tumor cells （CTCs） arise from primary or secondary tumors and enter the bloodstream by active or passive intravasation. Given the low number of CTCs, enrichment is necessary for detection. Filtration methods are based on selection of CTCs by size using a filter with 6.5 to 8 pm pores. After coloration, collected CTCs are evaluated according to morphological criteria. Immunophenotyping and fluorescence in situ hybridization techniques may be used. Selected CTCs can also be cultivated in vitro to provide more material. Analysis of genomic mutations is difficult because it requires adapted techniques due to limited DNA materials. Filtration-selected CTCs have shown prognostic value in many studies but multicentric validating trials are mandatory to strengthen this assessment. Other clinical applications are promising such as follow-up, therapy response prediction and diagnosis. Microfluidic emerging systems could optimize filtration-selected CTCs by increasing selection accuracy.展开更多
The wetting behavior between liquid aluminium and substrates made from industrial Al2O3 and SiC based ceramic foam filters （CFF） was investigated. The same CFF filters were also tested in plant scale filtration expe...The wetting behavior between liquid aluminium and substrates made from industrial Al2O3 and SiC based ceramic foam filters （CFF） was investigated. The same CFF filters were also tested in plant scale filtration experiments. The wetting experiment results show that the SiC based filter material is better wetted by liquid aluminium than the Al2O3 based filter material. This indicates that the improved wetting of aluminium on a filter material is an advantage for molten metal to infiltrate the filter during priming. Also, better wetting of Al-filter might increase the removal efficiency of inclusions during filtration due to better contact between filter and metal. Non-wetted inclusions are easier to be removed.展开更多
Aiming at disclosing the quantitative e ects of Coulomb forces on the ltration e ciency of aerosol particles, a three- dimensional random ber model was established to describe the microstructure of brous lters. Then, ...Aiming at disclosing the quantitative e ects of Coulomb forces on the ltration e ciency of aerosol particles, a three- dimensional random ber model was established to describe the microstructure of brous lters. Then, computational mod- els including the ow model, particle model, and electric eld model were constructed to estimate the ltration e ciency using the Fluent custom user-de ned function program, neglecting the non-uniformity of the ber potential and the particle charge distribution. The simulation results using the established models agreed with the data in the literature. In particular, the electric eld force was found to be one of the important factors required to improve the ltration e ciency estimation accuracy for the ultra ne particles. Moreover, the variation tendencies of the ltration e ciency and the pressure drop of brous lters were studied based on the in uence factors of the ber potential, particle charge-to-mass ratio, solid volume fraction, ber diameter, and face velocity. The established models and estimated results will provide important guidance on the design of high-e ciency particulate air lters for aerosol particles.展开更多
AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. O...AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. One eye of each rabbit was chosen randomly as antibody group and received subconjunctival injection of 0.1mL CTGF antibody (50mg/L) immediately after GFS applied and on the 5 th day after GFS. The other eye of each rabbit as control group was received subconjunctival injection of 0.1mL PBS at the same time as antibody group. On postoperative days 1, 3, 5, 7, 10, and 14, the appearance of filtrating blebs was observed under slit lamp, the area and the intraocular pressure (IOP) were measured with micrometer and applanation tonometer, respectively. RESULTS: On postoperative days 1, 3, 5, 7, 10, and 14, areas of filtrating blebs in antibody group were all larger comparing with the control group (P<0.05) and IOPs of antibody group were lower than the control group(P<0.05). CONCLUSION: Subconjunctival injection of CTGF antibody can maintain larger bleb area and lower IOP after GFS in rabbit.展开更多
BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization r...BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization rates increase in elderly patients due to a decline in glomerular filtration rate(GFR).AIM To investigate the connection between GFR and comorbidity and reasons for hospitalization in elderly patients.METHODS We analyzed patients aged 75 years and over who were admitted to the internal medicine clinic of a tertiary hospital in Eskisehir.At admission,we calculated GFR values using the Modification of Diet in Renal Disease study formula and classified them into six categories:G1,G2,G3a,G3b,G4,and G5.We analyzed associations with hospitalization diagnoses and comorbidity factors.RESULTS The average age of the patients was 80.8 years(±4.5 years).GFR was 57.287±29.5 mL/kg/1.73 m2 in women and 61.3±31.5 mL/kg/1.73 m2 in men(P=0.106).Most patients were admitted to the hospital at G2 stage(32.8%).The main reasons for hospitalization were anemia(34.4%and 28.6%)and malnutrition(20.9%and 20.8%)in women and men,respectively(P=0.078).The most frequent comor-bidity leading to hospitalization was arterial hypertension(n=168,28%),fo-llowed by diabetes(n=166,27.7%)(P=0.001).CONCLUSION When evaluating geriatric patients,low GFR alone does not provide sufficient information.Patients’comorbid factors should also be taken into account.There is no association between low GFR during hospitalization and hospitalization-Hamarat H.Aging and GFR related diagnoses.Knowing the GFR value before hospitalization will be more informative in such studies.展开更多
The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwa...The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.展开更多
The penetration and deposit of particles within the medium is thought to be one reason that the residual pressure drop of the rigid ceramic filter increase with cycle number.In this study,the change in the microstruct...The penetration and deposit of particles within the medium is thought to be one reason that the residual pressure drop of the rigid ceramic filter increase with cycle number.In this study,the change in the microstructure of a single layer ceramic filter candle during filtration-cleaning cycle was observed by scanning electron microscope(SEM) and the resistance property of the filter was monitored accordingly.The experimental results show that there exists a serious dust deposit within the filter medium,especially at the surface region.This should be responsible for the decrease of the filter permeability.The deposit law of dust in the filter medium during filtration-cleaning cycle was then studied by measuring the deposit depth,the deposit amount,the particles distribution within the medium,the size distribution of deposited particles,and so on.Particles migration and fine particles penetration were found to be the main reasons,for which dust deposit within the filter medium became aggravated with cycle number.Based on a differential form of Ergun equation,an expression for the pressure drop of a used ceramic filter was developed with a good agreement with experimental results.Then,the effect of dust deposit on the residual pressure drop was studied at the different face velocities and dust sizes.It was found that face velocity and dust size significantly influence dust deposit within filter medium,and then the operation performance of the filter.展开更多
In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and ...In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquidsystems, filtration at different flow rates, specitic cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, .and can be used as a reference for similar filtration applications.展开更多
Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental gover...Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via onestep electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901%(equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m^2) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.展开更多
AIM: To investigate the anti-scarring effect of sodium hyaluronate(HA) at filtration pathway after filtering surgery in a rabbit model.METHODS: Fifteen healthy adult New Zealand white rabbits were selected for trabecu...AIM: To investigate the anti-scarring effect of sodium hyaluronate(HA) at filtration pathway after filtering surgery in a rabbit model.METHODS: Fifteen healthy adult New Zealand white rabbits were selected for trabeculectomy in both eyes. The right eyes were used as HA group with 0.1 m L HA injected into the anterior chamber at the end of the operation;the left eyes were used with 0.1 m L sodium lactate Ringer’s solution(RS) injected into the anterior chamber as RS group. Intraocular pressure(IOP), filtering blebs morphology, inflammatory reaction and complications were observed at the 7, 60, and 90 d after surgery.RESULTS: One day after surgery, the IOP of HA and RS groups were 12.75±1.92 and 10.50±1.59 mm Hg(P=0.005). At the 7;day postoperative, the filtering blebs of each group were functional type and TGF-β expression was significantly difference in both groups(0.10±0.01 vs 0.14±0.02, P=0.024). After 60 d of the operation, all filtering blebs were scarring and alpha-smooth muscle actin(α-SMA) expression was significantly difference in both groups(0.40±0.04 vs 0.35±0.02, P=0.032). α-SMA positive cells were mainly distributed in the junction of conjunctiva and sclera and around the blood vessels. The collagen volume fraction(CVF) of HA and RS group was(75.49±7.01)% and(79.93±5.35)%(P=0.044). On the 90;day after the operation, CVF was(82.57±5.19)% and(88.08±1.75)% in HA and RS groups(P=0.036). There was no α-SMA positive cell in HA group, while a few positive cells were observed in RS group(P=0.000).CONCLUSION: HA has effect of anti-scar and antiinflammation on filtration pathway after filtering surgery within 3 mo by inhibiting fibroblast proliferation and collagen deposition.展开更多
Conventional Ceramic Foam Filter(CFF)technology has some difficulties in removing fine particulates(e.g.<20 μm)from liquid aluminium.In the present work the filtration behaviour of 30,50 and 80 ppi CFF filters hav...Conventional Ceramic Foam Filter(CFF)technology has some difficulties in removing fine particulates(e.g.<20 μm)from liquid aluminium.In the present work the filtration behaviour of 30,50 and 80 ppi CFF filters have been studied in the presence of magnetic fields in the range of 0.06-0.2T,produced by induction coils operated at 50 Hz. A feed recipe containing 90 wt.%of the aluminium alloy A356 doped with 10 wt.%A356 composite,containing 15 wt% SiC particles with a particle size ranging from 13 to 23 μm,was used.When the results obtained for the experiments conducted under the influence of a magnetic field where compared with similar reference gravity filtration experiments profound changes were observed in the distribution of particulates within,over and below the filter.Significant improvements in the wetting behaviour of the liquid metal to the CFF surface were also observed.It is believed that a successful change in filtration mechanisms is obtained as a result of the presence of the Lorentz forces and the metal recirculation produced by the magnetic field.The magnitude of the Lorentz forces,i.e.the magnetic pressure,are in the present work discussed in relation to the filtration results,and quantified based on experimental data and validated 2D axial symmetric Finite Element Modelling(FEM).展开更多
Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb rema...Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb remains the primary impediment to successful GFS outcomes.Perioperative utilization of antimitotics,while frontline in combating fibrosis and modulating the wound healing process,carries the risk of vision-threatening complications.Given the complexity of the wound healing cascade and the potential insufficiency of targeting a single molecule,there is an imperative to expand therapeutic modalities through combination therapies.This review offers a comprehensive elucidation of the fibrogenesis post-GFS,a synthesis unprecedented in the available literature,and aims to inform the broadening of therapeutic strategies for GFS.展开更多
Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltrat...Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltration,ultrafiltration,nanofiltration,and reverse osmosis.The present study focuses on the preparation of a novel porous CaCO_(3)microfiltration membrane,which is based on the microbial-induced calcium carbonate precipitation(MICP)biomineralization process.Initially,CaCO_(3) crystal particles with urease activity are prepared by controlling the MICP mineralization process.Secondary microbial mineralization is used to cement the loose calcium carbonate particles,forming a continuous porous solid CaCO_(3)membrane with certain mechanical strength.Filtration tests on bacterial cells,extracellular proteins,and polysaccharides show that the MICP-driven porous CaCO_(3) membrane effectively removes Escherichia coli,Brachybacterium sp.,and activated sludge,with removal rates of 99.998%,99.983%,and 99.996%,respectively.Compared to conventional filter paper,this porous CaCO_(3) membrane demonstrates superior capability in removing extracellular polymers(EPS).Furthermore,the CaCO_(3) microfiltration membrane prepared using the MICP process also exhibits ideal pore space,non-blocking characteristics,and high permeability.展开更多
Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor depositio...Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.展开更多
In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some import...In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b) .In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.展开更多
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.U21A2058 and U1860205)the Natural Science Funds of Hubei Province for Distinguished Young Scholars(Grant No.2020CFA088).
文摘Pure magnesia filter and periclase-spinel filter were prepared using porous MgO powder and Al2O3 micro-powder as raw materials.The filtration efficiency and purification mechanism of the two sets of filters on molten steel were investigated through steel casting tests.The results show that on the basis of surviving the thermal shock of molten steel,both filters can significantly reduce the number of non-metallic inclusions and total oxygen content of steel,thereby improving the cleanliness of the molten steel.After the thermal shock of molten steel,cracks were found in the microstructure of pure magnesia filter.Via the diffusion of non-metallic inclusions from steel into MgO grains of the filter to form solid solution,the inclusions were adsorbed to the internal and external surfaces of the pure magnesia filter.The number of inclusions was reduced by 62.5%,and the total oxygen content decreased from 0.892 to 0.265 wt.%after filtration,achieving a filtration efficiency of 70.3%.Compared with the pure magnesia filter,no cracks were found in the microstructure of the periclase-spinel filter.The mass transfer rate was accelerated due to the diffusion of inclusions from steel into MgO and MgAl2O4 grains of the filter,as well as the higher high-temperature liquid content and smaller pore structure of the filter.More non-metallic inclusions were able to enter the interior of the filter,which made the periclase-spinel filter more capable of adsorbing inclusions from steel and reducing total oxygen content.The periclase-spinel filter reduced the number of inclusions in steel by 84.4%and decreased the total oxygen content of the steel from 0.892 to 0.119 wt.%,with a filtration efficiency of 86.7%,demonstrating excellent comprehensive performance.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB4601400).
文摘Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid waste green synthesis characteristics.However,traditional manufacturing processes face challenges in pore structure control for mullite ceramics and obtaining desirable mechanical properties,which limits their application.Recently,ceramic 3D-printing technology has emerged as a research hotspot,and its effectiveness for manufacturing complex 3D porous ceramic structures and controlling their mechanical properties has been demonstrated.This paper provides a detailed overview of the precursor system and toughening mechanisms of mullite,3D-printing technology for mullite ceramics,3D porous structure design for filters,and the melt purification mechanisms of these filters.The objective of this study was to use 3D-printing technology to efficiently manufacture mullite ceramic filter elements with customized structures,controllable pore characteristics,and desirable mechanical properties.
基金Projects(5117604551276056)supported by the National Natural Science Foundation of China+1 种基金Projects(201208430262201306130031)supported by the National Studying Abroad Foundation of the China Scholarship Council
文摘Taking wall-flow diesel particulate filter(DPF) as the research objective and separately assuming its filtering wall to be composed of numerous spherical or cylindrical elements, two different mathematical models of steady filtration for wall-flow diesel particulate filter were developed and verified by experiments as well as numerically solved. Furthermore, the effects of the macroand micro-structural parameters of filtering wall and exhaust-flow characteristic parameters on trapping efficiency were also analyzed and researched. The results show that: 1) The two developed mathematical models are consistent with the prediction of variation of particulate size; the influence of various factors on the steady trapping efficiency is exactly the same. Compared to model 2, model 1 is more suitable for describing the steady filtration process of wall-flow diesel particulate filter; 2)The major influencing factors on steady trapping efficiency of wall-flow diesel particulate filter are the macro-and micro-structural parameters of filtering wall; and the secondary influencing factors are the exhaust-flow characteristic parameters and macro-structural parameters of filter; 3)The steady trapping efficiency will be improved by increasing filter body volume, pore density as well as wall thickness and by decreasing exhaust-flow, but effects will be weakened when particulate size exceeds a certain critical value; 4) The steady trapping efficiency will be significantly improved by increasing exhaust-flow temperature and filtering wall thickness, but effects will be also weakened when particulate size exceeds a certain critical value; 5) The steady trapping efficiency will approximately linearly increase with reducing porosity, micropore aperture and pore width.
基金supported by the National High Technology Research and Development Program of China(863)(No.2013AA065304)
文摘This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（CDPF）. Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number（SPN） was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration.
文摘Circulating tumor cells （CTCs） arise from primary or secondary tumors and enter the bloodstream by active or passive intravasation. Given the low number of CTCs, enrichment is necessary for detection. Filtration methods are based on selection of CTCs by size using a filter with 6.5 to 8 pm pores. After coloration, collected CTCs are evaluated according to morphological criteria. Immunophenotyping and fluorescence in situ hybridization techniques may be used. Selected CTCs can also be cultivated in vitro to provide more material. Analysis of genomic mutations is difficult because it requires adapted techniques due to limited DNA materials. Filtration-selected CTCs have shown prognostic value in many studies but multicentric validating trials are mandatory to strengthen this assessment. Other clinical applications are promising such as follow-up, therapy response prediction and diagnosis. Microfluidic emerging systems could optimize filtration-selected CTCs by increasing selection accuracy.
基金the Research Council of Norway (RCN) funded BIP Project No. 179947/I40 and BIA Project No. 219940/O30the partners: Alcoa Norway ANS, SAPA Heat Transfer AB, Hydro Aluminium AS, SINTEF MK Trondheim, and NTNUFunding by the industrial partners and RCN
文摘The wetting behavior between liquid aluminium and substrates made from industrial Al2O3 and SiC based ceramic foam filters （CFF） was investigated. The same CFF filters were also tested in plant scale filtration experiments. The wetting experiment results show that the SiC based filter material is better wetted by liquid aluminium than the Al2O3 based filter material. This indicates that the improved wetting of aluminium on a filter material is an advantage for molten metal to infiltrate the filter during priming. Also, better wetting of Al-filter might increase the removal efficiency of inclusions during filtration due to better contact between filter and metal. Non-wetted inclusions are easier to be removed.
基金supported by the National Key Research and Development Program (No. 2016YFC1201503)Natural Science Foundation of China (No. 21576206)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R46)
文摘Aiming at disclosing the quantitative e ects of Coulomb forces on the ltration e ciency of aerosol particles, a three- dimensional random ber model was established to describe the microstructure of brous lters. Then, computational mod- els including the ow model, particle model, and electric eld model were constructed to estimate the ltration e ciency using the Fluent custom user-de ned function program, neglecting the non-uniformity of the ber potential and the particle charge distribution. The simulation results using the established models agreed with the data in the literature. In particular, the electric eld force was found to be one of the important factors required to improve the ltration e ciency estimation accuracy for the ultra ne particles. Moreover, the variation tendencies of the ltration e ciency and the pressure drop of brous lters were studied based on the in uence factors of the ber potential, particle charge-to-mass ratio, solid volume fraction, ber diameter, and face velocity. The established models and estimated results will provide important guidance on the design of high-e ciency particulate air lters for aerosol particles.
基金Natural Science Foundation of Shaanxi Province,China(No.2001SM66)
文摘AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. One eye of each rabbit was chosen randomly as antibody group and received subconjunctival injection of 0.1mL CTGF antibody (50mg/L) immediately after GFS applied and on the 5 th day after GFS. The other eye of each rabbit as control group was received subconjunctival injection of 0.1mL PBS at the same time as antibody group. On postoperative days 1, 3, 5, 7, 10, and 14, the appearance of filtrating blebs was observed under slit lamp, the area and the intraocular pressure (IOP) were measured with micrometer and applanation tonometer, respectively. RESULTS: On postoperative days 1, 3, 5, 7, 10, and 14, areas of filtrating blebs in antibody group were all larger comparing with the control group (P<0.05) and IOPs of antibody group were lower than the control group(P<0.05). CONCLUSION: Subconjunctival injection of CTGF antibody can maintain larger bleb area and lower IOP after GFS in rabbit.
文摘BACKGROUND With an increase in the elderly population,the frequency of hospitalizations in recent years has also risen at a rapid pace.This,in turn,has resulted in poor outcomes and costly treatments.Hospitalization rates increase in elderly patients due to a decline in glomerular filtration rate(GFR).AIM To investigate the connection between GFR and comorbidity and reasons for hospitalization in elderly patients.METHODS We analyzed patients aged 75 years and over who were admitted to the internal medicine clinic of a tertiary hospital in Eskisehir.At admission,we calculated GFR values using the Modification of Diet in Renal Disease study formula and classified them into six categories:G1,G2,G3a,G3b,G4,and G5.We analyzed associations with hospitalization diagnoses and comorbidity factors.RESULTS The average age of the patients was 80.8 years(±4.5 years).GFR was 57.287±29.5 mL/kg/1.73 m2 in women and 61.3±31.5 mL/kg/1.73 m2 in men(P=0.106).Most patients were admitted to the hospital at G2 stage(32.8%).The main reasons for hospitalization were anemia(34.4%and 28.6%)and malnutrition(20.9%and 20.8%)in women and men,respectively(P=0.078).The most frequent comor-bidity leading to hospitalization was arterial hypertension(n=168,28%),fo-llowed by diabetes(n=166,27.7%)(P=0.001).CONCLUSION When evaluating geriatric patients,low GFR alone does not provide sufficient information.Patients’comorbid factors should also be taken into account.There is no association between low GFR during hospitalization and hospitalization-Hamarat H.Aging and GFR related diagnoses.Knowing the GFR value before hospitalization will be more informative in such studies.
基金The financial support from the National Natural Science Foundation of China(22127812,22278433,22178379)the National Key Research and Development Program of China(2021YFC2800902)are gratefully acknowledged。
文摘The mechanism of hydrate-based desalination is that water molecules would transfer to the hydrate phase during gas hydrate formation process,while the salt ions would be conversely concentrated in the unreacted saltwater.However,the salt concentration of hydrate decomposed water and the desalination degree of hydrate phase are still unclear.The biggest challenge is how to effectively separate the hydrate phase and the remaining unreacted salt water,and then decompose the hydrate phase to measure the salt concentration of hydrate melt water.This work developed an apparatus and pressure-driven filtration method to efficiently separate the hydrate phase and the remaining unreacted saltwater.On this basis,the single hydrate phase was obtained,then it was dissociated and the salt concentration of hydrate melt water was measured.The experimental results demonstrate that when the initial salt mass concentration is 0.3% to 8.0%,the salt removal efficiency for NaCl solution is 15.9% to 29.8%by forming CO_(2) hydrate,while for CaCl_(2) solution is 28.9%to 45.5%.The solute CaCl_(2) is easier to be removed than solute NaCl.In addition,the salt removal efficiency for forming CO_(2) hydrate is higher than that for forming methane hydrate.The multi-stage desalination can continuously decrease the salt concentration of hydrate dissociated water,and the salt removal efficiency per stage is around 20%.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20040425007)
文摘The penetration and deposit of particles within the medium is thought to be one reason that the residual pressure drop of the rigid ceramic filter increase with cycle number.In this study,the change in the microstructure of a single layer ceramic filter candle during filtration-cleaning cycle was observed by scanning electron microscope(SEM) and the resistance property of the filter was monitored accordingly.The experimental results show that there exists a serious dust deposit within the filter medium,especially at the surface region.This should be responsible for the decrease of the filter permeability.The deposit law of dust in the filter medium during filtration-cleaning cycle was then studied by measuring the deposit depth,the deposit amount,the particles distribution within the medium,the size distribution of deposited particles,and so on.Particles migration and fine particles penetration were found to be the main reasons,for which dust deposit within the filter medium became aggravated with cycle number.Based on a differential form of Ergun equation,an expression for the pressure drop of a used ceramic filter was developed with a good agreement with experimental results.Then,the effect of dust deposit on the residual pressure drop was studied at the different face velocities and dust sizes.It was found that face velocity and dust size significantly influence dust deposit within filter medium,and then the operation performance of the filter.
文摘In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquidsystems, filtration at different flow rates, specitic cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, .and can be used as a reference for similar filtration applications.
基金supported by the Science and Technology Project of Chaoyang District, Beijing, China (CYGX1709)the National Key R & D Program of China (2017YFE0101500)
文摘Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via onestep electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901%(equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m^2) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.
基金Supported by National Natural Science Fundation of China(No.81974132No.81770927)+1 种基金National Key R&D Program of China(No.2021YFA1101202)Hunan Provincial Health Commission(No.202207022839)。
文摘AIM: To investigate the anti-scarring effect of sodium hyaluronate(HA) at filtration pathway after filtering surgery in a rabbit model.METHODS: Fifteen healthy adult New Zealand white rabbits were selected for trabeculectomy in both eyes. The right eyes were used as HA group with 0.1 m L HA injected into the anterior chamber at the end of the operation;the left eyes were used with 0.1 m L sodium lactate Ringer’s solution(RS) injected into the anterior chamber as RS group. Intraocular pressure(IOP), filtering blebs morphology, inflammatory reaction and complications were observed at the 7, 60, and 90 d after surgery.RESULTS: One day after surgery, the IOP of HA and RS groups were 12.75±1.92 and 10.50±1.59 mm Hg(P=0.005). At the 7;day postoperative, the filtering blebs of each group were functional type and TGF-β expression was significantly difference in both groups(0.10±0.01 vs 0.14±0.02, P=0.024). After 60 d of the operation, all filtering blebs were scarring and alpha-smooth muscle actin(α-SMA) expression was significantly difference in both groups(0.40±0.04 vs 0.35±0.02, P=0.032). α-SMA positive cells were mainly distributed in the junction of conjunctiva and sclera and around the blood vessels. The collagen volume fraction(CVF) of HA and RS group was(75.49±7.01)% and(79.93±5.35)%(P=0.044). On the 90;day after the operation, CVF was(82.57±5.19)% and(88.08±1.75)% in HA and RS groups(P=0.036). There was no α-SMA positive cell in HA group, while a few positive cells were observed in RS group(P=0.000).CONCLUSION: HA has effect of anti-scar and antiinflammation on filtration pathway after filtering surgery within 3 mo by inhibiting fibroblast proliferation and collagen deposition.
基金Item Sponsored by RIRA (Remelting and Inclusion Refining of Aluminium) Project Funded by the Norwegian Research Council (NRC) -BIP Project No.179947/I40
文摘Conventional Ceramic Foam Filter(CFF)technology has some difficulties in removing fine particulates(e.g.<20 μm)from liquid aluminium.In the present work the filtration behaviour of 30,50 and 80 ppi CFF filters have been studied in the presence of magnetic fields in the range of 0.06-0.2T,produced by induction coils operated at 50 Hz. A feed recipe containing 90 wt.%of the aluminium alloy A356 doped with 10 wt.%A356 composite,containing 15 wt% SiC particles with a particle size ranging from 13 to 23 μm,was used.When the results obtained for the experiments conducted under the influence of a magnetic field where compared with similar reference gravity filtration experiments profound changes were observed in the distribution of particulates within,over and below the filter.Significant improvements in the wetting behaviour of the liquid metal to the CFF surface were also observed.It is believed that a successful change in filtration mechanisms is obtained as a result of the presence of the Lorentz forces and the metal recirculation produced by the magnetic field.The magnitude of the Lorentz forces,i.e.the magnetic pressure,are in the present work discussed in relation to the filtration results,and quantified based on experimental data and validated 2D axial symmetric Finite Element Modelling(FEM).
基金Supported by Hospital Level Project of the Eye Hospital of China Academy of Chinese Medical Sciences(No.GSP5-40)Internal Project of the Eye Hospital of China Academy of Chinese Medical Sciences(No.1011632).
文摘Glaucoma filtration surgery(GFS)stands as the most effective intervention for reducing intraocular pressure,a critical component in glaucoma management.Despite its pivotal role,the scarring of the filtration bleb remains the primary impediment to successful GFS outcomes.Perioperative utilization of antimitotics,while frontline in combating fibrosis and modulating the wound healing process,carries the risk of vision-threatening complications.Given the complexity of the wound healing cascade and the potential insufficiency of targeting a single molecule,there is an imperative to expand therapeutic modalities through combination therapies.This review offers a comprehensive elucidation of the fibrogenesis post-GFS,a synthesis unprecedented in the available literature,and aims to inform the broadening of therapeutic strategies for GFS.
基金Jiangsu Province Key Project of Research and Development Plan(No.BE2020676)Nantong Science and Technology Project(No.MS22021006)。
文摘Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltration,ultrafiltration,nanofiltration,and reverse osmosis.The present study focuses on the preparation of a novel porous CaCO_(3)microfiltration membrane,which is based on the microbial-induced calcium carbonate precipitation(MICP)biomineralization process.Initially,CaCO_(3) crystal particles with urease activity are prepared by controlling the MICP mineralization process.Secondary microbial mineralization is used to cement the loose calcium carbonate particles,forming a continuous porous solid CaCO_(3)membrane with certain mechanical strength.Filtration tests on bacterial cells,extracellular proteins,and polysaccharides show that the MICP-driven porous CaCO_(3) membrane effectively removes Escherichia coli,Brachybacterium sp.,and activated sludge,with removal rates of 99.998%,99.983%,and 99.996%,respectively.Compared to conventional filter paper,this porous CaCO_(3) membrane demonstrates superior capability in removing extracellular polymers(EPS).Furthermore,the CaCO_(3) microfiltration membrane prepared using the MICP process also exhibits ideal pore space,non-blocking characteristics,and high permeability.
基金The National Natural Science Foundation of China(No.51576043)
文摘Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.
文摘In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b) .In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.
