Filtrate Quality Research Articles

Experimental Study of Filtration Materials Used in the Car Air Intake.

Traditional cellulose filter media used for air filtration in vehicle engines are characterized by 99.9% filtration efficiency and accuracy above 2–5 µm. The highest engine component wear is caused by dust grains above 1 µm. Filter media with nanofiber additions provide greater filtration efficiency of dust grains below 5 µm. Filter material selection for vehicle engine air filter is a problem because their manufacturers mainly provide only the structure parameters: pore size, air permeability, and thickness. There is no information about material filtration properties using polydisperse test dust. The manuscript presents methodology and experimental test results of five samples A, B, C, D and E, filter materials differing in their chemical composition and structure parameters. In the first stage, efficiency characteristics φw, filtration accuracy dzmax and the flow resistance Δpw depending on the dust absorption coefficient km of three filter cartridges of each material, A, B, C, D and E, were determined. Then, from each material characteristics of one piece was selected in order to compare their initial and initial period efficiencies as well as changes in the flow resistance depending on the dust absorption coefficient km. Obtained results showed that the filter materials differ significantly in efficiency and accuracy values in the initial filtration period. Initial period duration is also different, i.e., filtration efficiency increasing time to a certain value, which for materials with a nanofiber layer is much shorter, which minimizes engine component wear. For materials with nanofibers, flow resistance increase intensity is greater, which results from surface filtration. Filtration efficiency of each filter material sample A, B, C, D and E was assessed with the filtration quality coefficient including the efficiency and flow resistance. In the available literature, the problem of increasing filtration efficiency in the initial period is known, but there are no results for specific filter materials. Research shows that filter material characteristics are closely related. Each increase in efficiency and accuracy of intake air filtration reduces engine components wear, but it is related to flow resistance increase in the engine intake system, which reduces its power, and increases need for more frequent filter servicing.

ПАРАМЕТРЫ ФИЛЬТРАЦИИ ЛАПЛАСИАНОМ-ГАУССИАНОМ МИКРОСКОПИЧЕСКИХ ИЗОБРАЖЕНИЙ МОКРОТЫ, ОКРАШЕННОЙ ПО МЕТОДУ ЦИЛЯ – НИЛЬСЕНА

Автоматизация задач медицинской диагностики влечет за собой подбор методов предобработки и классификации, оптимальных для построения соответствующей информационной системы. В статье рассмотрена задача улучшения операции фильтрации изображений микроскопии мокроты, окрашенной по методу Циля – Нильсена, без потерь регионов интереса, содержащих микобактерии туберкулеза. Автор предлагает использовать операцию свертки с дискретной маской лапласиана-гауссиана. В статье показан процесс получения дискретного фильтра с использованием эффекта повышения высоких частот для его улучшения. Предложен критерий нормализованной цветоразности с погрешностью для автоматического определения качества фильтрации.

COVID-19: In the Absence of Vaccination – ‘Mask the Nation’

COVID-19: In the Absence of Vaccination – ‘Mask the Nation’

Thermal Hydrolysis of Municipal sludge: Finding the Temperature Sweet Spot: A Review

The increasing demand for a Thermal Hydrolysis Process (THP) to pretreat municipal sludge upstream Anaerobic Digestion (AD) opens the opportunity to further develop and optimise this technology. The optimal THP temperature remains unclear due to the production of refractory compounds at high temperature. A compilation of literature data was conducted to investigate the existence of a temperature sweet spot for the THP applied to municipal sludge. All related reports (n = 43) were included. The THP temperature range impact was assessed in the range of 100 °C–200 °C on four AD and dewatering performance indicators (CH4 production, Volatile Solid Reduction (VSR), Dewaterability (DW) and filtrate quality). Other parameters potentially affecting the performance indicators were also considered. These parameters include the type of sewage sludge and operational conditions related to THP and AD. The impact of all parameters on performance indicators was evaluated with a Kruskal–Wallis statistical test. For THP temperature optimisation, a pairwise comparison, using a Wilcoxon test, was made. A temperature optimum in the [140–160] °C range was proposed. It seemed to minimize the production of refractory compounds, while maximising AD and dewatering performances. It is noteworthy that above 160 °C, the concentration in refractory compounds and soluble COD increases sharply, thus leading to a potential deterioration of WWTP effluent quality. Optimal THP temperature range for an optimal outcome on both sludge and wastewater treatment lines.

Microchannel filter for air purification

AbstractIn this study, we propose a new design for a microchannel filter. The closed indoor environments with which we interact daily are sources of diseases for the respiratory system of human beings. Recommendations for the design of microchannel filters for indoor air purification are proposed, implementing low-cost microequipment technology (MET) for the manufacture of the elements that constitute a microfiltration system. For the microchannel filter production, we proposed to use MET, which is a miniaturization technology and can reduce manufacturing costs. The microchannel filter was 3.75 cm in radius with a thickness of 3 mm. It had a triangular profile and a helical trajectory. It was designed, manufactured, and tested for two profile dimensions. The main purpose was to reduce the pressure drop of the air flow through the filter. We described the air flow simulation for the microchannel filter using SolidWorks. A prototype microchannel filter was constructed, which underwent manufacturing tests. It is possible to clean the microchannel using water flow, which allows us to maintain the filtration quality within an optimum range of contaminant removal.

Therapeutic approaches to the Rational Use of trip-le combination therapy with a fixed combination of amlodipine, indapamide and perindopril arginine (TRIPLE COMBINATION) in patients with hypertension who do not control blood pressure on conventional treatment. (Description and main results of the TRIO program)

Aim To study tactics of outpatient physicians in choosing the treatment when the previous double antihypertensive therapy (AHT) fails and to analyze the effectivity of an amlodipine/indapamide/perindopril arginine triple combination (TC).Material and methods The program included 1252 patients with arterial hypertension (AH); the TC group consisted of 992 (79.23 %) patients (38.3 % males; age, 61.6 [55.0; 67.9]); the control group included 260 (20.77 %) patients (37.7 % males; age, 60.6 [53.3; 67.4]). The main inclusion criteria were essential AH, age 18-79 years, insufficient response to previous AHT (clinical systolic blood pressure (SBP) >140-179 mm Hg). The study duration was three months. The following parameters were evaluated: dynamics of clinical and ambulatory BP (BP self-monitoring (BPSM); frequency of achieving the first goal of <140 / 90 mm Hg and the goal of <130 / 80 mm Hg); and changes in glomerular filtration rate (GFR) and quality of life (QoL). Responses to TC were analyzed in groups with different ranges of increased baseline SBP in patients with AH and diabetes mellitus (DM)/impaired glucose tolerance (IGT), overweight or obesity, and chronic kidney disease (CKD, reduced estimated GFR (eGFR <60 ml/min/1.73 m2). Safety was evaluated based on records of adverse events (AEs).Results The TC group had a more severe condition at baseline by clinical parameters and history and had higher baseline BP, which made difficult the intergroup comparison. Nevertheless at three months, the decrease in clinical SBP was more pronounced in the TC group (from 162.1 to 126.8 mm Hg, Δ=35.7 mm Hg) than in the control group (from 157.8 to 128.4 mm Hg, Δ=29.4 mm Hg). 87.8% of patients in the TC group and 81.9 % (р=0.012) in the control group achieved the first BP goal of <140 / 90 mm Hg; 34.3% and 28.2% of patients, respectively, achieved the BP goal of <130 / 80 mm Hg (р=0.055). The more effective SBP control in the TC group was associated with a pronounced BP decrease with higher BP values at baseline, which was also confirmed by an analysis in subgroups with SBP 140-160, 160-180, and >180 mm Hg. The TC treatment was associated with a pronounced antihypertensive effect with respect of BPSM values, improved QoL, and renal function. Significant decreases in BP and achievement of BP goals by a vast majority of patients receiving TC were also observed in subgroups with DM or IGT, overweight and/or obesity, and CKD. AEs were observed during the treatment only in 8 patients (0.64 %), which confirmed good tolerability and high safety of the therapy.Conclusion The study results demonstrated a therapeutic effect of the amlodipine/indapamide/perindopril arginine fixed-dose combination (Triplixam®). This effect was evident as control of clinical BP with any baseline BP level, including different ranges of increased SBP, in AH combined with DM, IGT, obesity, and CKD, which offers advantages over a subjective choice of AHT. TC improved BPSM values, QoL indexes, provided nephroprotection, and was well tolerated.

Performance of composite polyester filter with magnetic NdFeB particles on filtering welding fume particles

Welding fume particles can pose serious health risks because of its nanoscaled size and pulmonary toxicity. The main components of welding fume particles are iron oxides, most of which are easily magnetized in a magnetic field and subject to magnetic attraction. According to this characteristic, we developed a magnetic composite filter composed of a polyester filter and neodymium iron boron (NdFeB) particles to improve the filtering effect on fume particles. The performance parameters of magnetic filter were studied experimentally. At 5 cm/s face velocity, the filtration efficiency and quality factor of magnetic filter #4 were 2.09 times and 1.55 times of those of filter #0 (no NdFeB particles coated), respectively. In the loading process, the particles accumulation did not weaken the magnetic attraction effect. The filtration efficiencies of magnetic and nonmagnetic filters for 600 nm particles increased by 10.53% at 14.65 g/m2 and 8.17% at 14.33 g/m2, respectively.

The Effect of Alum as Filter Conditioner on the Performance of Conventional Rapid Sand Filter

Filtration is a one of the most important and critical unit process followed worldwide which removes dirt particles from water. As the water quality standards are changing and becoming more stringent, the improvement in the performance of existing rapid sand filters is unavoidable. The use of filter conditioning to improve filter performance is a relatively recent development in drinking water treatment. Different advantages claimed by such use of filter aid includes lessening ripening period, superior turbidity removal and relatively stable filtrate quality. It also has limitations like reduction in filter run and comparatively higher back washing requirement. To assess the suitability of such method,under the existing conditions is of enormous importance.12 Current research explains the impact of filter media conditioning on the overall performance of conventional rapid sand filter. The study was carried out by installing a pilot plant at Ichalkaranji municipal water treatment plant. Different doses of alum as filter conditioner were tested and the comparison was made with the performance of conventional filter without filter aid. The parameters for evaluation were turbidity removal, filter run and backwash requirements. The dose of alum as filter conditioner was given as slug dose. The effect of zeta (ζ) potential change was observed to be one of the major reasons of the performance improvement, accelerating the surface removal since initial phase.

Zeolitic Imidazolate Framework-8/Polypropylene-Polycarbonate Barklike Meltblown Fibrous Membranes by a Facile in Situ Growth Method for Efficient PM2.5 Capture.

Environmental pollution, especially air pollution, seriously endangers public health globally. Due to severe air pollution, air filters still face many challenges, especially in terms of filtration performance and filtration stability. Herein, a zeolitic imidazolate framework-8/polypropylene-polycarbonate barklike meltblown fibrous membrane (PPC/ZIF-8) was designed through meltblown and an in situ growth method, achieving efficient PM2.5 capture and high filtration stability under a harsh environment. After in situ growth, the PPC/ZIF-8 membrane could dramatically enhance the PM2.5 filtration efficiency without increasing the pressure drop; the PM2.5 filtration efficiency and quality factor were up to 32.83 and 116.86% higher than those of the pure PPC membrane, respectively. Moreover, through five filtration-wash-dry cycles, the PM2.5 filtration performance is still at a high level. This PPC/ZIF-8 membrane provides a new strategy for the preparation of an air filter with excellent comprehensive filtration performance.

Electrospinning of ABS nanofibers and their high filtration performance

Acrylonitrile–butadiene–styrene (ABS) is a commercial polymer for widely industrial applications due to its good mechanical and physical properties. However, there are only countable reports regarding its fibers from electrospinning. Comprehensive investigation on its optimized electrospinning parameters is missing. Herein, ABS fibers with different fiber diameters were produced by electrospinning. The electrospinning conditions, including the solvents, solution concentrations and amounts of different salt additives, have been comprehensively investigated. The morphologies of electrospun ABS fibers are studied by scanning electron microscopy and Raman spectroscopy. Different fiber diameters and coating densities are applied for filtration applications, which showed excellent filtration performance. The filtration efficiency of up to 99%, low pressure drop of < 30 Pa, and high filtration quality factor of up to 0.477 are achieved from the electrospun ABS fibers coated on microfibrous polypropylene substrates. In addition, the electrospun ABS fibers also shows good thermal stability and other applications such as oil/water separation.

3D structure design and simulation for efficient particles capture: The influence of nanofiber diameter and distribution

Software simulation is a convenient and efficient way to design and check different air filter structures with high efficiency and low pressure drop. In this work, nanofiber filters of different diameters ranging from 100 to 900 nm were designed to check their influence on filtration efficiency, pressure drop and quality factor (QF). Slip-flow effect of air molecules was considered on the surface of single fiber. Then, filters with different diameter distributions were constructed to study the filtration efficiency discrepancy when the filter thickness and porosity were kept equal. With a rotation of the filters composed of nanofibers of 500 nm in diameter in the computational domain, the filtration efficiency and QF increased steadily. The simulation results were partially verified by electrospun cellulose acetate nanofiber filter, and meanwhile provide with new insights into the filter structure design of high filtration efficiency with low pressure drop.

Characterisation of the impact of dissolved organic matter on iron, manganese, and arsenic mobilisation during bank filtration

Bank filtration (BF) has been used for many years as an economical technique for providing high-quality drinking water. However, under anaerobic conditions, the aquifer release of undesirable metal(loid)s, such as iron manganese, and arsenic, reduces the bank filtrate quality and thus restricts the application of this technique. This study investigates the impact of the organic-matter composition of source water on the mobilisation of Fe, Mn, and As during the anaerobic BF process. A laboratory-scale column study was conducted at a controlled-temperature (30 ± 2 °C) using different feed water sources. The organic matter characteristics of the feed water were elucidated using excitation-emission spectroscopy techniques integrated with parallel factor framework clustering analysis (PFFCA) model. The experiment was performed at redox conditions between 66 mv and −185 mv. Moreover, batch studies were implemented to study the effect of natural organic matter type (humic, fulvic and tyrosine) and concentration on the mobilisation of the selected metal(loids). The laboratory experiments demonstrated that the mobilisation of Fe, Mn and As during the BF are varied with the organic water concentration and composition of the source water. The fluorescence results revealed that terrestrial and condensed structure humic compounds are more capable to release Fe into the filtrate water. In contrast, Mn exhibited an equal tendency of mobilisation towards all the humic compounds regardless of its origin and structure. However, at a humic concentration higher than 5 mg-C/L, Mn showed more affinity towards lower molecular weight humic compounds. Arsenic was found to be the least impacted by the alteration in the source water organic matter composition; its mobilisation was highly correlated with iron releasing process. On the other hand, the biodegradable organic matter at high concentration (>10 mg-C/L) was found to be highly effective to turn the infiltration area into Fe-reducing environment and thereby elevating Fe and As concentrations in the pumped water. In conclusion, this study revealed that the DOM composition and concentration of the raw water could play an important role in the mobilisation of metal(loids) during the BF processes.

The Method and Analysis of Pore Size Distribution of Gas Separation Membrane by Gas Adsorption Equipment

In the membrane industrial field, from improving the quality of filtration for water treatment, separation technology of medical field, performance improvement of the electrode and separator of the battery, and dust filter, the pore size distribution is very important to maintain its quality. In recent years, research and development of gas separation membrane has been actively researched. For the analysis of ultra–micro pores of Angstrom order, Anton–Paar can offer a more accurate pore size distribution by new analysis technology NLDFT and QSDFT that simulates the behavior of fluid in the pores. The pore size analysis technology and our product line–up that are related to the membrane are introduced in this Journal.

Optimization of water use in a rapid filtration system: A case study

The objective of this research was to reduce water use during the operation of anthracite-sand filters used for treating drinking water. The variables that affect the saturation of the filter bed were evaluated, using procedures proposed by the Pan American Center for Sanitary Engineering and Environmental Sciences (CEPIS). The following were evaluated: filtration velocity, initial filtration quality, filtration runs duration, filter bed expansion, duration of the washing process, washing velocity, granulometry, and mud balls. The results obtained were compared with the design parameters recommended by CEPIS. Maximum turbidity of 0.5 NTU was obtained. Filtration runs were in the lower limit of the range indicated by CEPIS. The filter medium expansion in five of the eight filters was lower than recommended by CEPIS. The optimal washing time was 18 min. The washing velocity was low producing little filter bed expansion. The granulometric result indicated that the effective size and the anthracite uniformity coefficient were different between filters. The results also presented significant improvements in the filtration process and the amount of water saved once the filter washing process was optimized. The results also demonstrated that measuring filters performance could improve the filtration system efficiency and ensure the drinking water quality.

Test Process and Results of Potential Masking of Sterilizing-Grade Filters.

Pre-use/post-sterilization integrity testing (PUPSIT) has been a widely debated topic for the last several years. To a large extent, the debate is because of the fact that scientific data were not available to provide additional clarity that could inform appropriate risk-based judgements and commensurate actions. To gain clarity, the Parenteral Drug Association (PDA) and BioPhorum Organizations Group (BioPhorum) formed the Sterile Filtration Quality Risk Management (SFQRM) consortium in late 2017. The consortium goals have been to fill existing gaps in scientific data as adequately as possible with studies and industry guidance that would provide professionals and license holders with the ability to make informed decisions about appropriate risk-management strategies. This paper is one in a series of publications that are the result of the collaboration, and these should be considered together and viewed holistically in order to determine the best course of action with regard to PUPSIT. In total, the four papers cover the following areas: (1) data mining to determine the influence of fluid properties on integrity test values, (2) filter masking studies and results (this publication), (3) risk assessment and management from filter production to end use, and (4) points to consider in the best practice of the use of PUPSIT. In total, 25 manufacturers and filter suppliers have contributed to the work of the Consortium, deploying their filtration experts and pooling their collective knowledge and applied science experience to address these questions. This effort has also been supported by many independent experts currently available who have contributed to and driven the Filtration Interest Group in the PDA for many years. Both PDA and BioPhorum have prioritized this program and combined their approaches to deliver this comprehensive body of work. We hope that collectively the publications aid decision making and create greater certainty and confidence and above all alignment between suppliers, manufacturers, and regulators alike on these important questions.

Anthropic and Meteorological Controls on the Origin and Quality of Water at a Bank Filtration Site in Canada

At many bank filtration (BF) sites, mixing ratios between the contributing sources of water are typically regarded as values with no temporal variation, even though hydraulic conditions and pumping regimes can be transient. This study illustrates how anthropic and meteorological forcings influence the origin of the water of a BF system that interacts with two lakes (named A and B). The development of a time-varying binary mixing model based on electrical conductivity (EC) allowed the estimation of mixing ratios over a year. A sensitivity analysis quantified the importance of considering the temporal variability of the end-members for reliable results. The model revealed that the contribution from Lake A may vary from 0% to 100%. At the wells that were operated continuously at &gt;1000 m3/day, the contribution from Lake A stabilized between 54% and 78%. On the other hand, intermittent and occasional pumping regimes caused the mixing ratios to be controlled by indirect anthropic and/or meteorological forcing. The flow conditions have implications for the quality of the bank filtrate, as highlighted via the spatiotemporal variability of total Fe and Mn concentrations. We therefore propose guidelines for rapid decision-making regarding the origin and quality of the pumped drinking water.

Effect of different sediment dewatering techniques on subsequent particle sizes in industrial derived effluent

A paucity of literature has compared geotextile dewatering methods to more conventional dewatering methods (i.e., centrifuge, sedimentation) in the context of how geotextile dewatering performs at reducing particulate matter in dewatering effluent. Particulate matter is the primary source of inorganic and organic contaminants (i.e., dioxins and furans) in an unconsolidated sediment (estimated 577 000 m3) that has accumulated in a wastewater stabilization basin in Nova Scotia, Canada. Physical and chemical properties of contaminated sediment were initially characterized, and subsequent laboratory experiments were carried out for three common dewatering methods: sedimentation, centrifugation, and geotextile filtration. Filtrate quality of suspended solids (number, particle size distribution of particles) was examined for differences based on three dewatering techniques assessed. All three methods provided effective removal of particulate matter during dewatering, but geotextile dewatering could be a more cost-effective and practical solution for dewatering of these sediments.

Experimental Evaluation of Multiple Channel SDR Signal Receivers Effectiveness

Introduction. The SDR technology makes it possible to build multichannel signal receivers for replacing single-channel devices. In this the amount of real time calculations grows considerably. For these calculations it is expedient to apply parallel computations based on the multi-core central and graphic processors. The theoretical efficiency evaluation of the such receivers ignores many factors. The purpose of the article is an experimental efficiency evaluation of the SDR multichannel signal receivers’ construction.Modeling, analysis and testing. The multichannel research firmware receiver consisted of an SDR receiver, a USB controller and a computer. On a computer in a single server shell worked functionally completed software signal processingmodules.They provided reception of IQ-samples from the SDR receiver, their transfer to zero frequency, low-frequency filtration with decimation of the received samples. The experimental dependences of the maximum number of receiving channels from the decimation coefficient are obtained. At a decimation coefficient from 20 to 100 dependencies are hyperbolic, and from 100 to 10000 dependencies are directly proportional. The obtained dependences on the direct proportional section are approximated by the method of least squares. For a selected hardware platform, the proportionality coefficient is 6,1 for filters from 61 to 1001 order and 0,8 for filters from 1001 to 3901 order.Conclusions. It’s possible to increase the number of receiving channels by: increasing the decimation coefficient. The group signal and receiving channel spectrum bandwidth are the source data. Therefore, there is no possibility to increase the number of receiving channels by the decimation coefficient; decreasing filter order. The signal filtering quality depends from the filter order. Therefore, the choice of the filter order requires a compromise. The adequacy of the selected filter order to ensure a qualitative filtration with a given decimation coefficient is experimentally evaluated by the ratio of the given filtration band to the received. The obtained dependencies confirm the theoretical data: to ensure a high-quality filter with the increase of the decimation coefficient the order of the filter should be increased. With a fixed decimation coefficient, in order to achieve qualitative filtration, the order of the filter should be increased. It’s will reduce the number of receiving channels. To increase the number of receiving channels it’s necessary to reduce the order of the filter, which will lead to deterioration of the filtration quality.

Fabrication of Multifunctional Filters via Online Incorporating Nano‐TiO2 into Spun‐Bonded/Melt‐Blown Nonwovens for Air Filtration and Toluene Degradation

AbstractMultifunctional air filters with high filtration efficiency for aerosol and good degradation for toluene and bacteria are fabricated via online incorporation of TiO2/Ag nanoparticles into the composite nonwovens with spun‐bonded/melt‐blown (SM) hierarchical structure. Today, severe environmental pollution attributed to atmospheric pollutants, mainly including particulate materials, and gaseous volatile organic compounds, as well as bacterial and viral contaminants, has drawn worldwide attention. In this work, a novel online incorporation technique to fabricate a multifunctional air filter with hierarchical structure of SM nonwovens and TiO2 based nanoparticles is proposed. The in situ incorporation technique not only enables the SM nonwovens filters with four orders increment on toluene degradation rate, but also increases filtration quality factor Qf of the SM filters to 0.2251 Pa−1. This research shows promising applications of the multifunctional TiO2/SM nonwoven filters for indoor air remediation. In addition, this scale‐up fabrication method of fiber‐based filters will potentially promote engineering of macromolecular fiber materials.

Grid-Connected Shunt Active LCL Control via Continuous Sliding Modes

An LCL grid-connected three-phase and three-wire shunt active filter (SAF) is studied and controlled. It is known that SAFs generate distortive components caused by the high switching frequency of a voltage source inverter (VSI). In order to prevent the spread of these distortive components to the grid, the LCL filter (usually controlled by a linear control feedback) is used; while a parasitic phase shift/lag between the reference and injected currents emerges and severely deteriorates the filtration quality. In this study, the inherently robust sliding mode controller (SMC) is used in the SAF, for reducing the phase-shift effects over the broad bandwidth, while improving robustness to system's disturbances. Furthermore, in order to prevent very high frequency switching of the SMC that can severely hurt the switching elements, two different continuous SMCs are employed and studied. In the first solution, a signum function used in discontinuous SMC is replaced by a continuous sigmoid function. The second proposed solution uses an artificial increase of input-output relative degree that allows designing the SMC in terms of the control derivative, while the actual SMC function becomes continuous by integrating the discontinuous SMC. The output of the continuous SMC is pulse width modulated (PWM) in order to provide a fixed given frequency of control switching, required for the VSI safe operation. The proposed approach was validated on a mathematically modeled conventional nonlinear load and a real textile factory (Aleppo, Syria) via simulation based on real measurements coming from power quality analyzers. A new modeling approach of nonlinear loads is proposed and the efficacy of the proposed controllers for SAF/ LCL filter, even under unbalanced conditions, is validated via simulations.