This ranearch is focused on the, develonment of a simnle design model of the submerged catalysis/membrane filtration （catalysis/MF） system for phenol hydroxylation over TS-1 based on the material balance of the phen...This ranearch is focused on the, develonment of a simnle design model of the submerged catalysis/membrane filtration （catalysis/MF） system for phenol hydroxylation over TS-1 based on the material balance of the phenol under steady state and the reported kinetic studies. Based on the developed model, the theoretical phenol Conversions at steady state could be calculated using the kinetic parameters obtained from the previous batch experiments. The theoretical conversions are in good agreement with the experimental data obtained in the submerged catalysis/MF system within relative error of ±5%. The model can be used to determine the optimal experimental conditions to carry out the phenol hydroxylation over TS-1 in the submerged catalysis/MF system.展开更多
Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined acti...Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.展开更多
The conventional fixed-bed biofilm process has disadvantages of easily blocked,high headloss and short operation cycle.For overcoming these disadvantages,a multi-stage biofilm reactor(MSBFR),in which the lightweight f...The conventional fixed-bed biofilm process has disadvantages of easily blocked,high headloss and short operation cycle.For overcoming these disadvantages,a multi-stage biofilm reactor(MSBFR),in which the lightweight floating filter was dominant,was set up and operated.For detail investigation of the system when treating municipal wastewater,the succession characteristic of microbial community was analyzed by polymerase chain reaction(PCR)-Denaturing Gradient Gel Electrophoresis(DGGE)method.The results showed that the process had high efficiency to removal COD,SS and NH4+-N.The concentration of COD,SS and NH4-N in effluent were maintained lower than 40 mg/L,5 mg/L and 2 mg/L even though the concentration of COD,SS and NH4+-N in influent were 232-663 mg/L,105-245 mg/L and 23.7-62.7 mg/L,respectively,and the empty bed retention time was 3 h.Furthermore,biofilm samples taken from the column 2nd in height were analyzed by PCR-DGGE.The result of PCR-DGGE analysis showed that the microbial community had a little change in height and the dominant groups were Paracoccus sp.,Lactobacillus delbrueckii,Pseudomonas sp.and Bacteroidetes bacterium.展开更多
Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortage...Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortages, unmanaged stormwater, and increasing river water pollution. To supplement the need for non-potable water and address stormwater runoff pollution, we constructed a low cost stormwater filtration system. The filtration system is comprised of a sedimentation area followed by three gravel grain sizes arranged horizontally from coarse to medium to fine filter media. We compared the quality of pretreatment water with post-treatment water by measuring physicochemical parameters, heavy metals and nutrients. We found that the filtration system reduced turbidity by 87%, TSS by 80%, Cu by 87% and Zn by 90%. Further, it positively increased the concentration of DO by 42%. However, the filtration system did not remove nitrates and nitrites. Implementing this system at outfalls in the rapidly expanding condominium housing areas can increase residents’ supply of non-potable water and reduce the amount of polluted stormwater entering nearby streams and rivers.展开更多
A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated durin...A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated during the study.The experimental results show that for aperture diameters of 0.4,0.6,or 0.8 mm smaller apertures provide more complete filtration.Rotations of 12,20,28,or 40 r/min show that higher speeds give more efficient filtration.Suspended solids decreased in both particle size and concentration after the filtration.The separated slime can be directly reused as a fuel.Efficient filtration pretreatment systems for coal mine drainage were investigated and the economic feasibility is analyzed in this article.展开更多
The righteous book of Al-Quran mentions that the basic need of the living thing in this world is water. Resident of rural areas such as indigenous people will tap the highland aquatic resources as the main foundation ...The righteous book of Al-Quran mentions that the basic need of the living thing in this world is water. Resident of rural areas such as indigenous people will tap the highland aquatic resources as the main foundation for water. The reservoir is built on the top of hilly area to collect water before it discharges through a pipe system that uses the force of gravity to go down to the settlements. However, the filtration system frequently clogs and requires the occupants to climb up the reservoir hill for cleaning process. A lot of energy and time are required to manage the irrigation systems. Thus, an innovation system has been conducted as the filters will be cleaned automatically using solar energy supply. The designs of the filters are specially designed as the filter is equipped with electric motors, washer rods, power supply units, and automatic control box. The advantages of this project are the product will filtered the water as remain as natural highland watering resources while using the solar energy to accomplished green technology application.展开更多
Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of p...Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of photocatalysts or membrane materials to improve their catalytic and filtration performance,the complex structures and interface mechanisms,as well as insufficient light utilization,are still often overlooked,limiting the overall performance improvement of photocatalytic membranes.This work provides an overview of enhancement strategies involving restricted area effects,external fields,such as mechanical,magnetic,thermal,and electrical fields,as well as coupling techniques with advanced oxidation processes(e.g.,O_(3),Fenton,and persulfate oxidation)for dual enhancement of photocatalysts and membranes.In addition,the synthesis method of photocatalytic membranes and the influence of factors,such as light source type,frequency,and relative position on photocatalytic membrane performance were also studied.Finally,economic feasibility and pollutant removal performance were further evaluated to determine the promising enhancement strategies,paving the way for more efficient and scalable applications of photocatalytic membranes.展开更多
AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mes...AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.展开更多
Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfal...Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration(BF).Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.This study investigated year-long variations of DOM concentrations and compositions in a surface water of a circulated outdoor pond(research facility)connected to a BF passage.DOM was dominated by humic substances and a changing pattern of DOM in surface water was observed throughout the year.A significant increase of DOM(~38%)in surface water was noted in August compared to November.The fluorescent DOM showed that DOM in summer was enriched with the degradable fraction whilst non-degradable fraction was dominated in winter.A constant(1.7±0.1 mg/L)effluent DOM was recirculated in the system throughout the year.DOM removal through BF varied between 4%to 39%and was achieved within a few meters after infiltration and significantly correlated with influent DOM concentration(R^(2)=0.82,p<0.05).However,no significant(p>0.05)change in the removal of DOM was observed in two subsurface layers(upper and lower).This study highlights the presence of a constant non-degradable DOM in the bank filtrate,which was not affected by temperature,redox conditions and UV radiations.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
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
The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering perfor...The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.展开更多
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
BACKGROUND Type 2 diabetes(T2D),as well as obesity,are risk factors for chronic kidney disease(CKD)and end-stage renal disease.The renal impacts of glucose-lowering and weight-lowering drugs and their potential benefi...BACKGROUND Type 2 diabetes(T2D),as well as obesity,are risk factors for chronic kidney disease(CKD)and end-stage renal disease.The renal impacts of glucose-lowering and weight-lowering drugs and their potential benefits in preventing CKD often guide clinicians in choosing them appropriately.Only limited data based on randomized controlled trials(RCTs)is currently available on the renal effects and safety profile of tirzepatide.AIM To explore the renal benefits and safety of tirzepatide vs controls.METHODS RCTs involving patients receiving tirzepatide for any indication in the intervention arm and placebo or active comparator in the control arm were searched through multiple electronic databases.The co-primary outcomes were percent change from baseline(CFB)in urine albumin-to-creatinine ratio(UACR)and absolute CFB in estimated glomerular filtration rate(eGFR;in mL/min/1.73 m^(2));the secondary outcome was tirzepatide’s renal safety profile.RevMan web was used to conduct meta-analysis using random-effects models.Outcomes were presented as mean differences(MD)or risk ratios with 95%confidence intervals.RESULTS Fifteen RCTs(n=14471)with mostly low risk of bias(RoB)were included.Over 26-72 weeks,tirzepatide 10 mg[MD-26.95%(-40.13,-13.76),P<0.0001]and 15 mg[MD-18.03%(-28.58,-7.47),P=0.0008]were superior to placebo in percent reductions of UACR.Tirzepatide,at all doses,outperformed insulin in percent reductions of UACR.Compared to the placebo,the percent UACR reduction was greater in subjects with T2D than those with obesity but without T2D(MD-33.25%vs-7.93%;P=0.001).The CFB in eGFR with all doses of tirzepatide was comparable[5 mg:MD 0.36(-1.41,2.14);10 mg:MD 1.17(-0.22,2.56);15 mg:MD 1.42(-0.04,2.88)];P>0.05 for all vs insulin.Tirzepatide(pooled and separate doses)did not increase the risks of adverse renal events,urinary tract infection,nephrolithiasis,acute kidney injury,and renal cancer compared to the placebo,insulin,and glucagon-like peptide-1 receptor agonists.CONCLUSION Short-term data from RCTs with low RoB suggests that tirzepatide positively impacts UACR without detrimental effects on eGFR in subjects with T2D and obesity without T2D,with a reassuring renal safety profile.Larger RCTs are warranted to prove the longer-term renal benefits of tirzepatide,which might also prevent eGFR decline and worsening of CKD.展开更多
For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another....For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.展开更多
In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with ...In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with N≥1,m>0,p>1,such that m(p-1)>1.We give a clear classification of the self-similar solutions of the form u(x,t)=(βt)^(-α/β)((βt)^(-1/β)|x|)withα∈R andβ=α[m(p-1)-1]+p,regular or singular at the origin point.The existence and uniqueness of some solutions are established by the phase plane analysis method,and the asymptotic properties of the solutions near the origin and the infinity are also described.This paper extends the classical results of self-similar solutions for degeneratep-Laplace heat equation by Bidaut-Véron[Proc Royal Soc Edinburgh,2009,139:1-43]to the doubly nonlinear degenerate diffusion equations.展开更多
Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regard...Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regarding the best methods to estimate glomerular filtration rate(eGFR)in older adults.Several studies suggest the use of an age-adjusted definition to improve accuracy and avoid overdiagnosis.In contrast,some researchers argue that such changes could complicate the classification of chronic kidney disease(CKD).Several formulas,including the Modification of Diet in Renal Disease,CKD-Epidemiology Collaboration,and Cockcroft-Gault equations,are used to estimate eGFR.However,each of these formulas has significant limitations when applied to older adults,primarily due to sarcopenia and malnutrition,which greatly affect both muscle mass and creatinine levels.Alternative formulas,such as the Berlin Initiative Study and the Full Age Spectrum equations,provide more accurate estimates of values for older adults by accounting for age-related physiological changes.In frail older adults,the use of cystatin C leads to better eGFR calculations to assess renal function.Accurate eGFR measurements improve the health of older patients by enabling better medication dosing.A thorough approach that includes multiple calibrated diagnostic methods and a detailed geriatric assessment is necessary for the effective management of kidney disease and other age-related conditions in older adults.展开更多
BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the long...BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the longitudinal changes in measured glomerular filtration rate(mGFR)in patients with autosomal dominant polycystic kidney disease(ADPKD).METHODS Analysis of an ambispective data base conducted on consecutive patients diagnosed with ADPKD.The mGFR was assessed by iohexol clearance;while eGFR was calculated by three different formulas:(1)The chronic kidney disease epidemiology collaboration(CKD-EPI);(2)Modification of diet in renal disease(MDRD);and(3)The 24-hour urine creatinine clearance(CrCl).The primary end-points were the mean change in mGFR between the baseline and final visit,as well as the comparison of the mean change in mGFR with the change estimated by the different formulas.RESULTS Thirty-seven patients were included in the study.As compared to baseline,month-6 mGFR was significantly decrease by-4.4 mL/minute±10.3 mL/minute(P=0.0132).However,the CKD-EPI,MDRD,and CrCl formulas underestimated this change by 48.3%,89.0%,and 45.8%respectively,though none of these differences reached statistical significance(P=0.3647;P=0.0505;and P=0.736,respectively).The discrepancies between measured and estimated glomerular filtration rate values,as evaluated by CKD-EPI(r=0.29,P=0.086);MDRD(r=0.19,P=0.272);and CrCl(r=0.09,P=0.683),were not correlated with baseline mGFR values.CONCLUSION This study indicated that eGFR inaccurately reflects the decline in mGFR and cannot reliably track changes over time.This poses significant challenges for clinical decision-making,particularly in treatment strategies.展开更多
The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to over...The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to overcome the disadvantages of two traditional air filtration system,electrostatic assisted air filtration system(combining HEPA and ESP)has been proven to achieve high filtration efficiency and low energy consumption simultaneously.Predicting of V-I characteristics of electrostatic filtration system with configuration of“pin to filter medium to grounded device”is very essential and challenging due to the back corona phenomenon.This study utilized the back-corona based current model to predict the V-I characteristics of electrostatic system with different filter medium types and“pin-to-filter”distances.Experiments are conducted to provide data for model validation by changing filter types and locations of discharge pin.The results indicated that both of the predicted values of total discharge current and back-corona induced current agreed well with the experimentally measured data.This validated mathematical model could be used for preliminary design of electrostatic assisted filtration system with configuration of“pin to filter to grounded device”.Based on the V-I characteristics predicted by the semi-empirical model,the electrostatic filtration efficiency could be estimated.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
基金Supported by the National-Basic Research Program of China （2009CB623406）, the National High Technology Research and Development Program of China （2007AA06A402） and the National Natural Science Foundation of China （20636020）.
文摘This ranearch is focused on the, develonment of a simnle design model of the submerged catalysis/membrane filtration （catalysis/MF） system for phenol hydroxylation over TS-1 based on the material balance of the phenol under steady state and the reported kinetic studies. Based on the developed model, the theoretical phenol Conversions at steady state could be calculated using the kinetic parameters obtained from the previous batch experiments. The theoretical conversions are in good agreement with the experimental data obtained in the submerged catalysis/MF system within relative error of ±5%. The model can be used to determine the optimal experimental conditions to carry out the phenol hydroxylation over TS-1 in the submerged catalysis/MF system.
基金supported by the Universiti Kebangsaan Malaysia Grant(Grant No.GUP-2014-077)
文摘Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.
基金Sponsored by the Research Funds of the Guangxi Key Laboratory of Environmental Engineering,Protection and Assessment(Grant No.0804K001)the Development Program for Outstanding Young Teachers in Harbin Institute of Technology(Grant No.HITQNJS.2008.044)
文摘The conventional fixed-bed biofilm process has disadvantages of easily blocked,high headloss and short operation cycle.For overcoming these disadvantages,a multi-stage biofilm reactor(MSBFR),in which the lightweight floating filter was dominant,was set up and operated.For detail investigation of the system when treating municipal wastewater,the succession characteristic of microbial community was analyzed by polymerase chain reaction(PCR)-Denaturing Gradient Gel Electrophoresis(DGGE)method.The results showed that the process had high efficiency to removal COD,SS and NH4+-N.The concentration of COD,SS and NH4-N in effluent were maintained lower than 40 mg/L,5 mg/L and 2 mg/L even though the concentration of COD,SS and NH4+-N in influent were 232-663 mg/L,105-245 mg/L and 23.7-62.7 mg/L,respectively,and the empty bed retention time was 3 h.Furthermore,biofilm samples taken from the column 2nd in height were analyzed by PCR-DGGE.The result of PCR-DGGE analysis showed that the microbial community had a little change in height and the dominant groups were Paracoccus sp.,Lactobacillus delbrueckii,Pseudomonas sp.and Bacteroidetes bacterium.
文摘Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortages, unmanaged stormwater, and increasing river water pollution. To supplement the need for non-potable water and address stormwater runoff pollution, we constructed a low cost stormwater filtration system. The filtration system is comprised of a sedimentation area followed by three gravel grain sizes arranged horizontally from coarse to medium to fine filter media. We compared the quality of pretreatment water with post-treatment water by measuring physicochemical parameters, heavy metals and nutrients. We found that the filtration system reduced turbidity by 87%, TSS by 80%, Cu by 87% and Zn by 90%. Further, it positively increased the concentration of DO by 42%. However, the filtration system did not remove nitrates and nitrites. Implementing this system at outfalls in the rapidly expanding condominium housing areas can increase residents’ supply of non-potable water and reduce the amount of polluted stormwater entering nearby streams and rivers.
基金support through Special Basic Research Fund of China Central University(No.2011QH01)Innovative Experiment Projects for Undergraduates
文摘A filtration system used without chemical agents for the pretreatment of turbid coal mine drainage is described in this paper.The influence of different aperture sizes and different motor speeds was investigated during the study.The experimental results show that for aperture diameters of 0.4,0.6,or 0.8 mm smaller apertures provide more complete filtration.Rotations of 12,20,28,or 40 r/min show that higher speeds give more efficient filtration.Suspended solids decreased in both particle size and concentration after the filtration.The separated slime can be directly reused as a fuel.Efficient filtration pretreatment systems for coal mine drainage were investigated and the economic feasibility is analyzed in this article.
文摘The righteous book of Al-Quran mentions that the basic need of the living thing in this world is water. Resident of rural areas such as indigenous people will tap the highland aquatic resources as the main foundation for water. The reservoir is built on the top of hilly area to collect water before it discharges through a pipe system that uses the force of gravity to go down to the settlements. However, the filtration system frequently clogs and requires the occupants to climb up the reservoir hill for cleaning process. A lot of energy and time are required to manage the irrigation systems. Thus, an innovation system has been conducted as the filters will be cleaned automatically using solar energy supply. The designs of the filters are specially designed as the filter is equipped with electric motors, washer rods, power supply units, and automatic control box. The advantages of this project are the product will filtered the water as remain as natural highland watering resources while using the solar energy to accomplished green technology application.
基金supported by the BRICS STI Framework Programme(No.52261145703)the Higher Education Discipline Innovation Project(National 111 Project,No.B16016)the Guangxi Key Research and Development Plan Project(AB24010117).
文摘Photocatalytic membranes hold significant potential for promoting pollutant degradation and reducing membrane fouling in filtration systems.Although extensive research has been conducted on the independent design of photocatalysts or membrane materials to improve their catalytic and filtration performance,the complex structures and interface mechanisms,as well as insufficient light utilization,are still often overlooked,limiting the overall performance improvement of photocatalytic membranes.This work provides an overview of enhancement strategies involving restricted area effects,external fields,such as mechanical,magnetic,thermal,and electrical fields,as well as coupling techniques with advanced oxidation processes(e.g.,O_(3),Fenton,and persulfate oxidation)for dual enhancement of photocatalysts and membranes.In addition,the synthesis method of photocatalytic membranes and the influence of factors,such as light source type,frequency,and relative position on photocatalytic membrane performance were also studied.Finally,economic feasibility and pollutant removal performance were further evaluated to determine the promising enhancement strategies,paving the way for more efficient and scalable applications of photocatalytic membranes.
基金Supported by the National Natural Science Foundation of China(No.82301211)Beijing Natural Science Foundation(No.J230028).
文摘AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.
基金supported by the German Academic Exchange Service (DAAD)and Higher Education Commission (HEC),Pakistan。
文摘Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration(BF).Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.This study investigated year-long variations of DOM concentrations and compositions in a surface water of a circulated outdoor pond(research facility)connected to a BF passage.DOM was dominated by humic substances and a changing pattern of DOM in surface water was observed throughout the year.A significant increase of DOM(~38%)in surface water was noted in August compared to November.The fluorescent DOM showed that DOM in summer was enriched with the degradable fraction whilst non-degradable fraction was dominated in winter.A constant(1.7±0.1 mg/L)effluent DOM was recirculated in the system throughout the year.DOM removal through BF varied between 4%to 39%and was achieved within a few meters after infiltration and significantly correlated with influent DOM concentration(R^(2)=0.82,p<0.05).However,no significant(p>0.05)change in the removal of DOM was observed in two subsurface layers(upper and lower).This study highlights the presence of a constant non-degradable DOM in the bank filtrate,which was not affected by temperature,redox conditions and UV radiations.
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funded by the Universiti Teknologi Malaysia(UTM)through research Grant Number:06E05.
文摘The increasing severity of air pollution necessitates more effective and sustained air filtration technology.Concurrently,the desire for more environmentally friendly,sustainable materials with better filtering performance and less environmental impact drives the move away from conventional synthetic membranes.This review presents lignocellulosic biocomposite(LigBioComp)membranes as an alternative to traditional synthetic membranes.It focuses on their materials,fabrication,and functionalization techniques while exploring challenges and proposing methods for resourceful utilization.Renowned for their abundance and renewable nature,lignocellulosic materials consist of cellulose,hemicellulose,and lignin.Various applications can benefit from their antibacterial properties,large surface area,and remarkable mechanical strength.LigBioComp membranes are fabricated through casting,electrospinning,and freeze-drying,with advancements in fabrication techniques enhancing their performance and applicability.It is suggested to use solvent-free or low-solvent techniques such as Layer-by-Layer assembly to minimize environmental impact.Freeze-drying and electrospinning with green solvents can be used for achieving specific membrane properties,though energy consumption should be considered.Apply dry-wet spinning and solvent casting processes selectively.Functional groups,including carboxyl,hydroxyl,or amino groups,can significantly improve the membrane’s capacity to capture particulate matter.Chemical etching or the precise deposition of nanoparticles can further optimize pore size and distribution.The choice of chemicals and methods is critical in functionalization,with silane coupling agents,polyethyleneimine,and polydopamine.Future research should prioritize refining fabrication methods,advancing functionalization strategies,and conducting performance and recyclability assessments on hybrid and composite materials.This will enhance integrated systems and contribute to the development of smart filters.
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.
文摘BACKGROUND Type 2 diabetes(T2D),as well as obesity,are risk factors for chronic kidney disease(CKD)and end-stage renal disease.The renal impacts of glucose-lowering and weight-lowering drugs and their potential benefits in preventing CKD often guide clinicians in choosing them appropriately.Only limited data based on randomized controlled trials(RCTs)is currently available on the renal effects and safety profile of tirzepatide.AIM To explore the renal benefits and safety of tirzepatide vs controls.METHODS RCTs involving patients receiving tirzepatide for any indication in the intervention arm and placebo or active comparator in the control arm were searched through multiple electronic databases.The co-primary outcomes were percent change from baseline(CFB)in urine albumin-to-creatinine ratio(UACR)and absolute CFB in estimated glomerular filtration rate(eGFR;in mL/min/1.73 m^(2));the secondary outcome was tirzepatide’s renal safety profile.RevMan web was used to conduct meta-analysis using random-effects models.Outcomes were presented as mean differences(MD)or risk ratios with 95%confidence intervals.RESULTS Fifteen RCTs(n=14471)with mostly low risk of bias(RoB)were included.Over 26-72 weeks,tirzepatide 10 mg[MD-26.95%(-40.13,-13.76),P<0.0001]and 15 mg[MD-18.03%(-28.58,-7.47),P=0.0008]were superior to placebo in percent reductions of UACR.Tirzepatide,at all doses,outperformed insulin in percent reductions of UACR.Compared to the placebo,the percent UACR reduction was greater in subjects with T2D than those with obesity but without T2D(MD-33.25%vs-7.93%;P=0.001).The CFB in eGFR with all doses of tirzepatide was comparable[5 mg:MD 0.36(-1.41,2.14);10 mg:MD 1.17(-0.22,2.56);15 mg:MD 1.42(-0.04,2.88)];P>0.05 for all vs insulin.Tirzepatide(pooled and separate doses)did not increase the risks of adverse renal events,urinary tract infection,nephrolithiasis,acute kidney injury,and renal cancer compared to the placebo,insulin,and glucagon-like peptide-1 receptor agonists.CONCLUSION Short-term data from RCTs with low RoB suggests that tirzepatide positively impacts UACR without detrimental effects on eGFR in subjects with T2D and obesity without T2D,with a reassuring renal safety profile.Larger RCTs are warranted to prove the longer-term renal benefits of tirzepatide,which might also prevent eGFR decline and worsening of CKD.
文摘For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.
基金supported by the NSFC(12271178,12171166)the Guangzhou Basic and Applied Basic Research Foundation(2024A04J2022)the TCL Young Scholar(2024-2027).
文摘In this paper,we study the self-similar solutions of the degenerate diffusion equation ut-div(|▽u^(m)|^(p-2)▽u^(m))=0 of polytropic filtration diffusion in R^(N)×(0,±∞)or(R^(N)/{0})×(0,±∞)with N≥1,m>0,p>1,such that m(p-1)>1.We give a clear classification of the self-similar solutions of the form u(x,t)=(βt)^(-α/β)((βt)^(-1/β)|x|)withα∈R andβ=α[m(p-1)-1]+p,regular or singular at the origin point.The existence and uniqueness of some solutions are established by the phase plane analysis method,and the asymptotic properties of the solutions near the origin and the infinity are also described.This paper extends the classical results of self-similar solutions for degeneratep-Laplace heat equation by Bidaut-Véron[Proc Royal Soc Edinburgh,2009,139:1-43]to the doubly nonlinear degenerate diffusion equations.
文摘Aging is an inevitable process that is usually measured by chronological age,with people aged 65 and over being defined as"older individuals".There is disagreement in the current scientific literature regarding the best methods to estimate glomerular filtration rate(eGFR)in older adults.Several studies suggest the use of an age-adjusted definition to improve accuracy and avoid overdiagnosis.In contrast,some researchers argue that such changes could complicate the classification of chronic kidney disease(CKD).Several formulas,including the Modification of Diet in Renal Disease,CKD-Epidemiology Collaboration,and Cockcroft-Gault equations,are used to estimate eGFR.However,each of these formulas has significant limitations when applied to older adults,primarily due to sarcopenia and malnutrition,which greatly affect both muscle mass and creatinine levels.Alternative formulas,such as the Berlin Initiative Study and the Full Age Spectrum equations,provide more accurate estimates of values for older adults by accounting for age-related physiological changes.In frail older adults,the use of cystatin C leads to better eGFR calculations to assess renal function.Accurate eGFR measurements improve the health of older patients by enabling better medication dosing.A thorough approach that includes multiple calibrated diagnostic methods and a detailed geriatric assessment is necessary for the effective management of kidney disease and other age-related conditions in older adults.
文摘BACKGROUND Equations for estimation glomerular filtration rate(eGFR)have been associated with poor clinical performance and their clinical accuracy and reliability have been called into question.AIM To assess the longitudinal changes in measured glomerular filtration rate(mGFR)in patients with autosomal dominant polycystic kidney disease(ADPKD).METHODS Analysis of an ambispective data base conducted on consecutive patients diagnosed with ADPKD.The mGFR was assessed by iohexol clearance;while eGFR was calculated by three different formulas:(1)The chronic kidney disease epidemiology collaboration(CKD-EPI);(2)Modification of diet in renal disease(MDRD);and(3)The 24-hour urine creatinine clearance(CrCl).The primary end-points were the mean change in mGFR between the baseline and final visit,as well as the comparison of the mean change in mGFR with the change estimated by the different formulas.RESULTS Thirty-seven patients were included in the study.As compared to baseline,month-6 mGFR was significantly decrease by-4.4 mL/minute±10.3 mL/minute(P=0.0132).However,the CKD-EPI,MDRD,and CrCl formulas underestimated this change by 48.3%,89.0%,and 45.8%respectively,though none of these differences reached statistical significance(P=0.3647;P=0.0505;and P=0.736,respectively).The discrepancies between measured and estimated glomerular filtration rate values,as evaluated by CKD-EPI(r=0.29,P=0.086);MDRD(r=0.19,P=0.272);and CrCl(r=0.09,P=0.683),were not correlated with baseline mGFR values.CONCLUSION This study indicated that eGFR inaccurately reflects the decline in mGFR and cannot reliably track changes over time.This poses significant challenges for clinical decision-making,particularly in treatment strategies.
基金The authors would like to acknowledge the coordinated support from Natural Science Foundation of China(Grant No.51808138,51778385,51878442).
文摘The widely utilized high efficient particulate air filters(HEPA)and electrostatic precipitator(ESP)respectively has the shortcomings of relatively high energy consumption and low filtration efficiency.In order to overcome the disadvantages of two traditional air filtration system,electrostatic assisted air filtration system(combining HEPA and ESP)has been proven to achieve high filtration efficiency and low energy consumption simultaneously.Predicting of V-I characteristics of electrostatic filtration system with configuration of“pin to filter medium to grounded device”is very essential and challenging due to the back corona phenomenon.This study utilized the back-corona based current model to predict the V-I characteristics of electrostatic system with different filter medium types and“pin-to-filter”distances.Experiments are conducted to provide data for model validation by changing filter types and locations of discharge pin.The results indicated that both of the predicted values of total discharge current and back-corona induced current agreed well with the experimentally measured data.This validated mathematical model could be used for preliminary design of electrostatic assisted filtration system with configuration of“pin to filter to grounded device”.Based on the V-I characteristics predicted by the semi-empirical model,the electrostatic filtration efficiency could be estimated.
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.
