Performance Of Filter Research Articles

Effect of inlet velocity on the hydraulic and filtering performance of a Y‐type screen filter

AbstractUneven sediment distribution affected by inlet velocity, particle size distribution and flow field characteristics leads to local clogging in a Y‐type screen filter. This study revealed the detailed flow field characteristics and distribution of sediments on the screen via computational fluid dynamics combined with the discrete element method (CFD–DEM) simulations and experimental tests. The results showed that the distribution of the flow rate on the filter screen was extremely uneven, with the maximum flow rate being 11.72 times greater than the minimum rate. The flow rate was distributed symmetrically on the two sides along the outlet centreline, as shown by the unfolded drawing of the filter core. Numerical simulation and experimental tests using sandy water showed that the number and average particle diameter on the screen decreased, and the number and average particle diameter in the plug increased, with increasing inlet velocity. The sediments on the screen were distributed intensively, and the plugging extent coefficient and the anti‐clogging performance improved. However, this process was more likely to cause local clogging and worsen the filtration performance. Therefore, low‐speed filtering should be applied if the filtering effect is needed, and high‐speed filtering should be applied if the filtering efficiency is favourable but the flushing frequency increases.

Filtration of dust particulates with a granular bed filter in a novel coupled separator

In this study, the filtration performance of the built-in granular bed in a cyclone-granular bed coupled separator is investigated. Cyclone is used to recover catalyst particles from the regenerated flue gas in the Fluid catalytic cracking by centrifugal force. While the granular bed captures fine dust particles smaller than 10 μm. Catalyst loss problem can be addressed by coupling different separation mechanisms in the coupled separator. To clarify the separation process, the necessity to elucidate the filtration performance is shown The investigation has been performed for the velocity distribution measuring and the bed dust deposition, and the filtration efficiency in the coupled separator under varying operating parameters. Experimental results indicate that the radial velocity component is a main influencing factor on the granular bed filtration efficiency. The outer-layer bed collector particles exhibit superior dust collection capabilities. Based on the intrusive dust sampling, a diagram is presented to clearly illustrate the primary mechanisms that govern dust movement in the bed. Furthermore, two parameters named by the local filtration efficiency (LFE) and the filtration efficiency across radius (FEAR) are proposed for analyzing the granular bed filter performance. The LFE exhibits a declining trend as the inlet air velocity increases. The dust size distribution analysis highlights the capacity of the bed to capture fine dust particles (<5 μm) which tended to accumulate at the inner layer. The FEAR, ranging from 91 % to 97 %, offers a comprehensive assessment of the coupled separator performance and structural optimization.

WAF and WMF to improve the performance of average and median filters

Salt and spice noise is considered one of the most common types of noise that affect grayscale and color digital images, as it affects them negatively, and this negative effect increases with an increase in the noise ratio. Many digital filters are used to mitigate the negative effects of salt and pepper noise, and the most widely used of these filters are the average filter and the median filter. The average and median filters work on processing all pixels in the image, whether these pixels are intact from the noise or infected with it, and accordingly, mitigating this noise, especially if it has a high noise ratio, is ineffective. In this research paper, new window average and window median filters will be proposed to enhance the performance of standard average and median filters. The proposed filter will treat the infected pixels, leaving the clean pixels as they were. For a noisy pixel, a special window will be created and the pixel value will equal the mean (or average) of the cleaned pixels in the window (excluding the noisy pixels). To simplify the window processing an index window will be used, this window will point to the noisy and cleaned pixels in the selected pixel window. Several images with various values of noise ratios will be tested; several windows with different sizes will be examined to get the most suitable window size. The selected window size will be used to filter various noisy images, the obtained results will be compared with average and median filter results to show the improvements provided by the proposed method.

Measurement of mechanical and thermal performance of cigarette filter fibres/eggshell particles reinforced polymer composite using integrated CRITIC-TODIM approach

The study investigates the development of polyvinyl ester (VE) composites reinforced with day-by-day litter discarded cigarette filter fibre (CFF), utilizing a compression moulding process. Carbonized chicken eggshell powder (ESP) is incorporated as a filler material in the matrix phase, varying in weight percentages (0 %, 3 %, and 5 %). To optimize mechanical properties, a multi-criteria decision-making (MCDM) approach, employing Criteria Importance through Inter-criteria Correlation (CRITIC) integrated with the TODIM (TOmada de Decisao Interativa Multicriterio) methodology, is utilized. Process control factors include CFF (40–60 wt%), fibre length (10–20 mm), and filler (0–5 wt%) at different levels. The CRITIC-TODIM optimization results highlight the significant impact of ESP filler on enhancing tensile, impact, and flexural properties in the fabricated composites. The integrated approach identifies that a combination of CFF at 60 wt%, fibre length of 20 mm, and ESP at 3 wt% yields optimal mechanical characteristics. Furthermore, thermo-gravimetric analysis indicates that the composite developed under these optimal conditions exhibits superior thermal stability compared to the composite without ESP filler.

Filtering Swamp Water into Clean Water Using Carbon Charcoal and Silica Sand Filter Media

Water filtration is an essential need in ensuring the quality of a safe water supply for the community around Meritai Raya Village Rt 027, Sungai Pinang Village, Rambutan District, Banyuasin Regency, South Sumatra Province. The method used was a completely randomized design (CRD) using activated carbon charcoal, silica sand, coir, gravel and filter cotton as media. The aim of the research is to determine the efficiency of the performance of swamp water processing filters in removing water quality parameters in the form of pH (Potential of Hydrogen) and TDS (Total Dissolved Solid). Design a which has 3 tubes uses filter media in the form of sand (12 cm), coir (15 cm), and cotton (3 cm) in tube 1, coir (20 cm), gravel (8 cm), and cotton (3 cm) in tube 2, carbon charcoal (8 cm) and cotton (10 cm) in tube 3. And design b which has 2 tubes in the form of gravel (6 cm), silica sand (12 cm), 8cm coir, and cotton (4 cm.) in tube 1. carbon charcoal (7 cm), coir (10 cm), and cotton (10 cm) in tube 2. The research results show that filtration is effective in reducing water pH and TDS in water, namely up to pH 7.6 and TDS 92 ppm in design A and pH 8.3 and TDS 104 ppm in design B even though it does not meet the clean water quality standards of Minister of Health Regulation No. 32 of 2017. The two filtration designs have performance effectiveness that is not much different in treating swamp water. However, overall filtration with the 3 tube variation has better performance.

Investigating the Performance of Gammatone Filters and Their Applicability to Design Cochlear Implant Processing System

Commercially available cochlear implants are designed to aid profoundly deaf people in understanding speech and environmental sounds. A typical cochlear implant uses a bank of bandpass filters to decompose an audio signal into a set of dynamic signals. These filters’ critical center frequencies f0 imitate the human cochlea’s vibration patterns caused by audio signals. Gammatone filters (GTFs), with two unique characteristics: (a) an appropriate “pseudo resonant” frequency transfer function, mimicking the human cochlea, and (b) realizing efficient hardware implementation, could demonstrate them as unique candidates for cochlear implant design. Although GTFs have recently attracted considerable attention from researchers, a comprehensive exposition of GTFs is still absent in the literature. This paper starts by enumerating the impulse response of GTFs. Then, the magnitude spectrum, |H(f)|, and bandwidth, more specifically, the equivalent rectangular bandwidth (ERB) of GTFs, are derived. The simulation results suggested that optimally chosen filter parameters, e.g., critical center frequencies,f0; temporal decay parameter, b; and order of the filter, n, can minimize the interference of the filter bank frequencies and very likely model the filter bandwidth (ERB), independent of f0b. Finally, these optimized filters are applied to delineate a filter bank for a cochlear implant design based on the Clarion processor model.

Adaptive Predictive Deadbeat Current Control of Single-Phase Multi-Tuned Shunt Hybrid Active Power Filters

This paper suggests an adaptive predictive deadbeat current control method for single-phase multi-tuned shunt hybrid active power filters (HAPFs) to improve the power quality of single-phase and three-phase four-wire utility grids. The HAPF structure eliminates the resonance between the passive power filter and the grid impedance. Furthermore, it can be integrated into passive filters to enhance their filtering performance. In this paper, a digital algorithm is proposed for managing the performance of each converter leg accurately. To do so, an exact model of the high-order system is developed, and the transfer function of the plant is calculated in continuous and discrete time domains. Then, a predictive deadbeat technique for HAPF current control is presented, which benefits from high accuracy, fast dynamics, and low sensitivity to system parameter mismatches. Extensive simulation and experimental tests are conducted and the results match well to confirm the success and appropriate performance of the overall system. Also, performance comparison with conventional solutions demonstrates the superiority of the suggested filtering technique.

Fouling Mitigation by Surface‐Patterned Polymeric Membranes in Water Treatment: A Review of Recent Advancements in Fabrication Techniques

AbstractThe world is constantly challenged regarding managing environmental and ecological contamination due to human and industrial activities. This is because of the constant threat posed by pollution. Nowadays, membrane‐based technology is a growing field, making practically all the separation of foulant from wastewater possible. The membrane fouling resulting from the interaction between the foulant and the membrane surface presents a challenge for the technology in maintaining performance over extended periods of operation. As a result, there is a rising interest in research focusing mainly on creating patterned membrane surfaces that reduce fouling and effectively enhance the surface area. This article comprehensively overviews the most recent and cutting‐edge techniques that can be applied to modify and construct high‐performance patterned membranes suitable for ultrafiltration, microfiltration, nanofiltration, and reverse osmosis (UF, MF, NF, and RO) water purification processes. In this study, recent developments in membrane material are dissected, focusing on methods for improving surface chemistry, structure, and hydrodynamics, as well as the consequences of these characteristics on filtering performance.

Shape optimization using the adjoint solver in computational fluid dynamics for additive manufacturing of a pollen filter

Pollen filters play an essential role in protecting people from airborne allergens and ensuring indoor air quality. Allergic reactions to pollen can lead to discomfort, reduced productivity, and increased healthcare costs. A low pressure drop of these pollen filters not only enhances the comfort of individuals using the filters but also contributes to energy savings in ventilation systems, thereby promoting environmental sustainability. This research focuses on the shape optimization of pollen filters using the adjoint solver in computational fluid dynamics, aiming to enhance both human health and environmental sustainability. In a previous study, an approach using the adjoint solver was developed to optimize both the separation efficiency and the pressure drop. In the current work, a methodology is presented that exploits these findings and allows the design of initial structures, subsequent optimization, and detailed experimental and numerical comparisons with a reference filter using the example of a pollen filter. To validate the effectiveness of the optimized filter, the initial geometry and the optimized geometry were fabricated and tested on a test bench. Compared to a reference filter, our filter disk was able to separate 2.9% more particles of size 6 μm and the pressure drop was lower by 34.2%. This research work demonstrates that the developed method can effectively be used to improve the performance of pollen filters. The results obtained from the validation suggest that the optimized geometry of the filter exhibits higher separation efficiency while keeping the pressure drop low compared to state-of-the-art pollen filters.

Filter Cleaning System Modification to Improve Dust Colletor

The filter cleaning system is part of the dust collector which functions as a filter between dirty air and clean air. Blockage of the dust collector is due to a lack of maintenance to control the performance of filter cleaning components such as valves, jetspray tubes and bagcloth. Another cause is the less than optimal air pressure from the jetspray to dislodge the dust adhering to the bagcloth. So it is necessary to recondition both the layout of the filter cleaning components and the optimization of jet spray pressure. Determination of the capacity of the jetspray tube is adjusted to the specifications of the compressor and uses the ASME VIII Div I (Pressure Vessel) standard with dimensions of 1400mm x 8inch SCH20. The feasibility test of the jetspray tube is carried out by calculating the allowable thickness and the factor of safety based on the pressure operated on the jetspray tube. Determining the location of the filter cleaning components is based on aspects that make it easier for the operator to carry out the maintenance so that the performance of the filter cleaning components can be controlled properly. Based on the stress simulation using solidworks 2020 for the SCH20 pipe which has a thickness of 6.35mm operated with a pressure of 7 bar it is categorized as safe to use.

Effect of air humidity on the pulse-jet cleaning performance of cartridge filter for collecting hygroscopic adhesive dusts

Pulse-jet cartridge filters are widely used in industrial dust removal. However, the accumulation of highly sticky dust can cause irreversible blockage of cartridges. This is primarily due to the humidity of the air on the cleaning performance of the filter cartridge. Therefore, this article proposed a new method to solve it by changing the injection air source (nitrogen, compressed air after suction dryer treatment and compressed air after cold dryer treatment), the influence of humidity on system strength and dust residues was assessed. We define absolute humidity above 10 g m−3 as a high humidity condition and vice versa as a low humidity condition. The conclusions are that the injection effect only considers the water content of the injection air source: nitrogen > compressed air after suction dryer treatment > compressed air after cold dryer treatment. In low humidity conditions, the injection air source is the main influence factor, plus the water content of the injection air source, the greater the resistance of the system and the dust residues. In high humidity conditions, the humidity of the air is the most important influence. When the gas-solid concentration and filtration wind speed are constant, the system strength and dust residues increase with the increase in humidity. This study provides new ideas and reliable data sources for the industrial collection of adhesive dust.

Trans-reflective tunable color filter using electro-optic material

This research presents designing a tunable trans-reflective color filter utilizing Barium Titanate (BTO) and optimizing its performance by applying an artificial intelligence (AI) based inverse design model. The AI-based color filter design process is efficient and minimizes design challenges. The AI model comprising two sub-blocks is trained using a dataset that correlates geometrical parameters, refractive index, and input voltage variations with desired color outputs to precisely control the color filter's performance. The first is the parametric optimization block (POB), which employs two deep neural networks (DNNs) in the forward and inverse directions to achieve the optimized geometry of the proposed meta-atoms. Once the optimal parameters are completed, the next block, i.e., voltage tuning block (VTB), is employed to map specific colors onto the refractive index and the applied voltage of the BTO layer. In this way, by changing the voltage of the BTO layer, we can leverage BTO's tunable optical properties, which allow for a broad range of vibrant and customizable colors. The optimized color filter demonstrates enhanced tunability and efficiency, opening up new possibilities for applications in displays and imaging devices.

Continuous–discrete derivative-free extended Kalman filter based on Euler–Maruyama and Itô–Taylor discretizations: Conventional and square-root implementations

In this paper, we continue to study the derivative-free extended Kalman filtering (DF-EKF) framework for state estimation of continuous–discrete nonlinear stochastic systems. Having considered the Euler–Maruyama and Itô–Taylor discretization schemes for solving stochastic differential equations, we derive the related filters’ moment equations based on the derivative-free EKF principal. In contrast to the recently derived MATLAB-based continuous–discrete DF-EKF techniques, the novel DF-EKF methods preserve an information about the underlying stochastic process and provide the estimation procedure for a fixed number of iterates at the propagation steps. Additionally, the DF-EKF approach is particularly effective for working with stochastic systems with highly nonlinear and/or nondifferentiable drift and observation functions, but the price to be paid is its degraded numerical stability (to roundoff) compared to the standard EKF framework. To eliminate the mentioned pitfall of the derivative-free EKF methodology, we develop the conventional algorithms together with their stable square-root implementation methods. In contrast to the published DF-EKF results, the new square-root techniques are derived within both the Cholesky and singular value decompositions. A performance of the novel filters is demonstrated on a number of numerical tests including well- and ill-conditioned scenarios.

Simulation study of a planar quadrupole mass filter for MEMS mass spectrometer

Micro-electro-mechanical system (MEMS) based mass spectrometry, MEMS mass spectrometry, emerges a new technique branch of miniature mass spectrometry. One of the main challenges hindering the development of MEMS mass spectrometry is the poor compatibility between the complex electrode structure of traditional ion optics and MEMS processes. This paper proposed a planar quadrupole mass filter utilizing a highly simplified stacked-layer structure and film electrodes, which is easy to fabricate with high precision by MEMS surface micromachining. The ion trajectory simulation model of the MEMS mass spectrometry chip involving all necessary ion optics was elaborated for investigating the preliminary performance of the planar quadrupole mass filter. By optimizing the crucial parameters such as the frequency of radio frequency voltage, the ratio of direct current voltage and radio frequency voltage, pre-pole length, main-pole length, and injection kinetic energy, the preliminary simulation result of planar quadrupole mass filter achieved a 1–2 Da peak width (at 50% of peak height) and 20–80% ion transmission efficiency. Importantly, the planar quadrupole mass filter demonstrated a maximum working pressure of 0.1 Pa (using air as the buffer gas), 100 times higher than that of conventional quadrupole mass filters, while maintaining a 0.7–1.8 Da peak width and ∼5% ion transmission efficiency. Additionally, to modify the theoretical formulas for the non-ideal quadrupolar field of planar quadrupole mass filter, a novel approach based on stability diagrams obtained by simulation was also introduced. The pretty good linearity (R2=1) between ion masses in the range of 10 to 100 Da and the corresponding radio frequency voltages was verified through the simulated mass spectra. Notably, the proportional coefficient of ion mass and radio frequency voltage exhibited a minimal 4% deviation between the simulated value (4.7132 V0P/Da) and the calculated value (4.9036 V0P/Da) through the modified formula. In conclusion, the preliminary simulation results demonstrated that the planar quadrupole mass filter possessed moderate performance, high-pressure tolerance, and excellent theoretical consistency, which proved it a promising technology of MEMS mass spectrometry. It can find applications in the fields of gas detection, including the rapid response to hazardous gas emissions and in situ detection of dissolved gases in the deep sea.

Improving process discovery by filtering noises based on event dependency

Process discovery techniques analyze process logs to extract models that characterize the behavior of business processes. In real-life logs, however, noises exist and adversely affect the extraction and thus decrease the understandability of discovered models. In this paper, we propose a novel double granularity filtering method, executed on both the event and trace levels, to detect noises by analyzing the directly-following and parallel relations between events. Based on the probability of an event occurring in a sequence, the infrequent behaviors and redundant events in the logs can be filtered out. In addition, the missing events in parallel blocks are detected to further improve the performance of filtering. Experiments on synthetic logs and five real-life datasets demonstrate that our method significantly outperforms other state-of-the-art methods.

Fuzzy based self-similarity weight estimation in non-local means for gray-scale image de-noising

Image de-noising in imaging systems is one of the most demanding issues that have been addressed in this work. Non-local mean filtering is gaining traction as a convincing method for image de-noising. Nevertheless, the performance of the traditional non-local mean filter is diminished by the computational expense of its weighted averaging process. In the proposed method, the similarity between the two patches of the image subspace is used to find the best weight for each pixel using a fuzzy inference algorithm. By using the similarity of non-local neighborhood pixels as an input antecedent in the input fuzzy set and the degree of weights as a consequent in the output fuzzy set, the fuzzy inference system which consists of IF-THEN rules, implication, and aggregation is employed. Eventually, de-fuzzification helps to measure how similar the pixels are to their non-local neighborhoods and estimates the fuzzy degrees of weight. Experiments on a variety of speckled noisy gray-scale images from standard and real public datasets demonstrate the improved performance of this fuzzy-based self-similar weight approximation in non-local mean filtering when compared to state-of-the-art image de-noising methods and sophisticated non-local mean methods in terms of standard evaluation metrics. Additionally, the suggested technique works satisfactorily when tested on actual speckled synthetic aperture radar images.

Realization of a Wide Stopband Filter Using the Weakest Electric Field Method and Electromagnetic Hybrid Coupling Method

To enhance filter performance in terms of stopband, we propose a wide-stopband substrate-integrated waveguide filter based on the rejection of higher-order modes. The filter establishes the inner and outer coupling windows at the mode’s weakest electric field to achieve mode suppression. Simultaneously, we employ the electromagnetic hybrid coupling theory to analyze the electromagnetic distribution of the particular modes and determine the dimensions of the coupling circular apertures and slits based on the extracted coupling coefficients to attain suppression of the specific modes. The filter successfully suppresses all higher-order modes having resonant frequencies below that of the TE150 mode, as demonstrated by simulation results. We conducted measurements and found that the filter has a center frequency of 4.78 GHz, a bandwidth of 100 MHz with a -3 dB attenuation, and a stopband of -25 dB that extends up to 16.62 GHz (i.e., 3.48 times the center frequency). Simulation and measurement results demonstrate a good correlation. This method, compared to other SIW filters, is easy to design, has a wider stopband range, can be readily applied to practical microwave communication systems, and has potential applications.

Improved Kalman Filter Based Inverter Control for Reduction of Low Order Current Harmonics due to Isolation Transformers in Renewable Energy Sources

This paper is focused on the analysis of a Kalman filter performance when introduced in the current control loop of a distributed generation connection inverter. The idea is to use this kind of filter to reduce the harmonic content of the currents injected in the point of common coupling. The study has been performed by means of simulation using Matlab-Simulink and clearly demonstrates that this kind of control system can improve the response produced by the inverters. The elimination of certain well-known noisy harmonics introduced by an element such as the isolation low voltage transformer has been accomplished.

A Control Strategy for Combined Series-Parallel Active Filter System under Non-Periodic Conditions

In this study, generalized non-active power theory based control strategy is proposed for a 3-phase 4-wire Combined Series-Parallel Active Filter (CSPAF) system using a Three-Dimensional (3D) Space Vector Pulse Width Modulation (SVPWM). The CSPAF system consists of a Series Active Filter (SAF) and a Parallel Active Filter (PAF) combination connected a common Direct Current (DC) link for simultaneous compensating the source voltage and the load current. The generalized non-active power theory was applied in previous studies for the PAF control, in this study the theory is used for the CSPAF system control under non-sinusoidal and nonperiodic current and voltage conditions. The closed loop control algorithm for the proposed CSPAF system has been described to direct control of filtering performance by measuring source currents and load voltages for the PAF and the SAF, respectively. The proposed control strategy has been verified by simulating the CSPAF system in Matlab/Simulink environment.

Realization of nth Order Wave Active Low-Pass Filter Using Differential Difference Current Conveyor

A wave active filter (WAF) based on a differential difference current conveyor (DDCC) is presented in this paper. An active filter formation depends entirely on wave quantity processing. The wave method is demonstrated for the basic wave active elements (WAEs) of active filters such as a series inductor and a shunt capacitor. The novelty of the proposed work is that the mathematical operations required to implement the wave active components, such as lossy integration-subtraction; subtraction; summation and inverter, are performed using the DDCC as an analog building block (ABB). Designing WAFs of lower to higher-order is extremely challenging, i.e., great motivation to propose a WFA using a CMOS-based DDCC for lower and higher-order low-pass Butterworth filter topologies. Additionally, the filter performances are verified through noise analysis, percentage total harmonic distortion (%THD) and Monte Carlo analysis. The proposed WFA is theoretically verified for [Formula: see text]th order low-pass Butterworth filter designs ([Formula: see text]) using DDCC-based WAEs and validated using SPICE simulations with [Formula: see text]m TSMC CMOS technology parameters for DDCC, operating on [Formula: see text][Formula: see text]V.