Series Of Filters Research Articles

Upgrade filter elements have enhanced performance and reduce energy costs

US-based filtration, separation and purification technology company Pall Corp has introduced a direct upgrade to its Coralon, Ultipor and Red 1000 series filters.

Quantification of the Thoracic Aorta and Detection of Aneurysm at CT: Development and Validation of a Fully Automatic Methodology.

To develop and validate a deep learning-based system that predicts the largest ascending and descending aortic diameters at chest CT through automatic thoracic aortic segmentation and identifies aneurysms in each segment. In this retrospective study conducted from July 2019 to February 2021, a U-Net and a postprocessing algorithm for thoracic aortic segmentation and measurement were developed by using a dataset (dataset A) that included 315 CT studies split into training, hyperparameter-tuning, and testing sets. The U-Net and postprocessing algorithm were associated with a Digital Imaging and Communications in Medicine series filter and visualization interface and were further validated by using a dataset (dataset B) that included 1400 routine CT studies. In dataset B, system-predicted measurements were compared with annotations made by two independent readers as well as radiology reports to evaluate system performance. In dataset B, the mean absolute error between the automatic and reader-measured diameters was equal to or less than 0.27 cm for both the ascending aorta and the descending aorta. The intraclass correlation coefficients (ICCs) were greater than 0.80 for the ascending aorta and equal to or greater than 0.70 for the descending aorta, and the ICCs between readers were 0.91 (95% CI: 0.90, 0.92) and 0.82 (95% CI: 0.80, 0.84), respectively. Aneurysm detection accuracy was 88% (95% CI: 86, 90) and 81% (95% CI: 79, 83) compared with reader 1 and 90% (95% CI: 88, 91) and 82% (95% CI: 80, 84) compared with reader 2 for the ascending aorta and descending aorta, respectively. Thoracic aortic aneurysms were accurately predicted at CT by using deep learning.Keywords: Aorta, Convolutional Neural Network, Machine Learning, CT, Thorax, AneurysmsSupplemental material is available for this article.© RSNA, 2022.

A Unified Power Quality Conditioner for Feeder Reconfiguration and Setting to Minimize the Power Loss and Improve Voltage Profile

Using devices such as unified power quality conditioners (UPQCs) in distribution networks seems essential for higher electricity quality. Moreover, distribution network reconfiguration is a suitable model for improving network characteristics, including loss reduction and voltage increase for distribution networks, and is widely used in this era. Here, the study discusses the rechanging of distribution networks for UPQC via proposing an appropriate model for it. In addition to the optimum structure of distribution networks, the most appropriate branch where UPQC must be located and the most appropriate reactive power size with which series and shunt filters must be injected into the grid are determined. The simulations have been applied on two 69‐ and 84‐standard‐bus networks. The results of the simulations indicate much power loss reduction and much voltage increase in the presence of UPQC compensators.

Measurements, Gas/Particle Partitioning, and Sources of Nonpolar Organic Molecular Markers at a Suburban Site in the West Yangtze River Delta, China

AbstractThis study seeks to understand the ambient levels, gas/particle partitioning, and sources of nonpolar organic molecular makers (OMMs) at a suburban site in Nanjing, China. Particle‐ and gas‐phase OMMs were collected using a medium volume sampler equipped with two quartz filters in series and a polyurethane foam (PUF)/XAD‐4/PUF (PXP) adsorbent sandwich. More than 100 pairs of filter and PXP samples were collected diurnally from September 2018 to September 2019. The concentration profiles of total n‐alkanes and polycyclic aromatic hydrocarbons were peaking at n‐C12–n‐C17 homologs (9.98 ± 5.43–38.4 ± 17.7 ng m−3) and naphthalene (92.5 ± 56.7 ng m−3), respectively, followed by decreasing concentrations with further increases in molecular weight. Three artifact correction methods with different pre‐assumptions on relative contributions of evaporation loss to backup filter measurements were used to separate particle‐ and gas‐phase OMMs. The resulting particle‐phase fractions showed significant differences for OMMs with vapor pressure <10−9 atm at 298.15 K. Absorptive gas/particle partitioning coefficients of OMMs were empirically calculated based on measurements and theoretically predicted for comparison. The results obtained under the three artifact correction methods suggested growing importance of evaporation loss with decreased vapor pressure. Positive matrix factorization (PMF) was performed for source apportionment using total (PMFtotal) and particle‐phase (PMFparticle) OMMs data, respectively. Besides eliminating the influence of gas/particle partitioning, the involvements of more volatile species and gaseous OMMs data improved the identification of specific emission sources, supporting the usage of total OMMs data over a wide vapor pressure range for PMF source apportionment.

Harmonic reduction in IEEE-3-bus using hybrid power filters

The development of industrial applications and the comprehensive uses of power systems has led to the emergence of harmonics, that non-linear loads are the cause of it. A hybrid power filters (HPFs) is an ideal solution in compensating reactive power and mitigating harmonic current. In this paper, the IEEE-3-bus system companied with the hybrid power filter is performed to reduce current harmonics and improved performance under many operation conditions. The system tested with two types of power filters: firstly, a shunt passive power filer and secondly, a shunt hybrid power filter: which consists of a passive power filter in series with an active power filter. Hybrid power filters simulation results with control strategy have the effectiveness in the reduction of current harmonics from (29.85%) to (0.78%) comparing with other types.

ATP Bioluminescence for Rapid and Selective Detection of Bacteria and Yeasts in Wine

Microbial contamination may represent a loss of money for wine producers as several defects can arise due to a microorganism’s growth during storage. The aim of this study was to implement a bioluminescence assay protocol to rapidly and simultaneously detect bacteria and yeasts in wines. Different wines samples were deliberately contaminated with bacteria and yeasts at different concentrations and filtered through two serial filters with decreasing mesh to separate bacteria and yeasts. These were resuscitated over 24 h on selective liquid media and analyzed by bioluminescence assay. ATP measurements discriminated the presence of yeasts and bacteria in artificially contaminated wine samples down to 50 CFU/L of yeasts and 1000 CFU/L of bacteria. The developed protocol allowed to detect, rapidly (24 h) and simultaneously, bacteria and yeasts in different types of wines. This would be of great interest for industries, for which an early detection and discrimination of microbial contaminants would help in the decision-making process.

Adaptive Response Behavior in the Pursuit of Unpredictably Moving Sounds.

Although moving sound-sources abound in natural auditory scenes, it is not clear how the human brain processes auditory motion. Previous studies have indicated that, although ocular localization responses to stationary sounds are quite accurate, ocular smooth pursuit of moving sounds is very poor. We here demonstrate that human subjects faithfully track a sound’s unpredictable movements in the horizontal plane with smooth-pursuit responses of the head. Our analysis revealed that the stimulus–response relation was well described by an under-damped passive, second-order low-pass filter in series with an idiosyncratic, fixed, pure delay. The model contained only two free parameters: the system’s damping coefficient, and its central (resonance) frequency. We found that the latter remained constant at ∼0.6 Hz throughout the experiment for all subjects. Interestingly, the damping coefficient systematically increased with trial number, suggesting the presence of an adaptive mechanism in the auditory pursuit system (APS). This mechanism functions even for unpredictable sound-motion trajectories endowed with fixed, but covert, frequency characteristics in open-loop tracking conditions. We conjecture that the APS optimizes a trade-off between response speed and effort. Taken together, our data support the existence of a pursuit system for auditory head-tracking, which would suggest the presence of a neural representation of a spatial auditory fovea (AF).

Impacts of sedimentation on rainwater quality: case study at Ikorodu of Lagos, Nigeria

Abstract This study investigated the impact of sedimentation on rainwater storage system using a case study at the Ikorodu area of Lagos state, a rural area in Nigeria. In this investigation, the proportions of Escherichia coli (E. coli) that were settleable (due to sedimentation) and those that were at the free phase have been studied. Water samples were collected from different depths in the inspected rainwater storage tank at two different periods (i.e. rainy and dry periods) for 20 days. The samples collected from these periods have been analysed for physical and microbial measures before passing it through the serial filters with pore sizes of 500 μm, 100 μm, 10 μm and 1.5 μm to measure the retained particle mass. From the results, it was observed that: (1) the water quality at the free-phase zone was better than that at the tank's bottom; (2) the settleable bacteria rapidly sank to bottom; (3) the correlation of turbidity, E. coli and total suspended solids (TSS) for all the rain events showed a relatively high Pearson's coefficient of 0.9 to one another; and (4) over 70% of settling TSS occurred within first 36 h. Finally, it has been found that the physical sedimentation process can significantly reduce the microbial measures.

Design of a continuously and linearly controlled VSI-based STATCOM for load current balancing purposes

In this paper, load current balancing are reviewed in both three-wire and 4-wire systems taking into account linearity, harmonics injection, and control schemes. A linearized static compensator (STATCOM) based on H-bridge voltage source inverter (VSI). The proposed STATCOM is controlled in closed loop mode via equipping it with a new current controller. The DC capacitor voltage of the STATCOM is kept constant without using external energy injection or storage devices via shunting the DC capacitor with a suitable series filter. The simulation results of the current responses of the 220V, 50Hz STATCOM reveal continuous and linear performance during responding to reactive current demands from 123A inductive current to 227A capacitive current. The transition time required for the proposed STATCOM during treatment of a sudden change in reactive current demand from maximum inductive current to maximum capacitive current is less than 40ms. The steady state portions of the STATCOM current responses show pure sinusoids, thus the proposed STATCOM can be promoted as harmonic free static Var compensator. The closed loop continuous mode control and the considerable linearity of the proposed STATCOM promot it as a bipolar susceptance (capacitive and inductive) in applications of load current balancing systems in both three and four wire power systems.

Experimental validation of solar PV sustained ZSI based unified active power filter for enrichment of power quality

The deployment of power electronic devices has become a big concern for power quality in these days. The voltage stabilization of power distribution networks interconnected with Photo Voltaic (PV) is very critical in promoting the smooth operation of all linked devices in the distribution system. Voltage profile maintenance is one of the challenges in PV integration into the grid. Conventional devices such as passive filters, series and shunt filters, synchronous condensers, etc. are insufficient to alleviate numerous problems of power quality. The series compensator is used for voltage quality and the shunt compensator is used for current quality. Also, if these two problems of power quality are simultaneously mitigated, the device is used in the distribution system known as Unified Active Power Filter (UAPF). The shunt and series compensator of UAPF is equipped with a Z-source inverter(ZSI). This paper addresses voltage and current associated existing power quality concerns which including voltage sag, voltage swell, voltage and current distortion and simulates the UAPF device to alleviate these problems. The Unit Vector Template Generation (UVTG) with Improved Second Order Generalized Integrator (ISOGI) based Phase Locked Loop (PLL) is utilized for UAPF controller simulation and experimental results validated the proposed work.

Investigation of a selectable multi-passband microwave photonic filter based on cascaded optical comb filters

A multi-passband microwave photonic filter (MPF) with selectable passband frequency, spanning 0–20 GHz frequency range, is proposed, and experimentally demonstrated, in which passband frequency can be flexibly selected within a maximum passband number to four. The scheme is based on the generation of tunable optical comb lines using a broadband optical source sliced by cascaded optical comb filters, achieved by connecting an in-line birefringence fiber filter and a reconfigurable Lyot filter in series, such that various filter tap spacing and spectral combinations are obtained for the configuration of the MPF. The proposed MPF can operate with four different passband states, namely, single-, dual-, triple-, and quadruple-passband, only by adjusting polarization states of the cascaded optical comb filters. All these passbands are with a 3-dB bandwidth varying from 200 to 460 MHz and more than 20-dB sidelobe suppression.

PID Control With Higher Order Derivative Degrees for IPDT Plant Models

In this paper, we discuss the main features of the generalized higher-order proportional-integrative-derivative control (HO-PID) based on the integral-plus-dead-time (IPDT) plant models. It was developed by extending the traditional PI-control to include $m$ th-order derivatives and $n\geq m$ th-order binomial series filters. The HO-PID control provides two additional degrees of freedom, which allow to appropriately modify the speed of the transients and the attenuation of the measurement noise, together with the closed-loop robustness. In this way, it pursues similar goals as an alternative fractional-order PID control. A broad family of the HO-PID controllers with the included low-pass filters is employed to solve a number of new problems. Their integrated suboptimal tuning, based on explicit formulas derived by the multiple real dominant pole (MRDP) method and evaluated by a novel approach that relates the speed of transients to the excessive input and output increments, has been simplified by introducing two integrated tuning procedures (ITPs). The main new finding is that HO-PID control enables faster transients by simultaneously reducing the negative effects of measurement noise and increasing the closed-loop robustness. A brief experimental evaluation using new sensitivity measures fully confirms the excellent HO-PID characteristics and shows that commissioning remains almost as simple as with the filtered PI-control.

Grid integration of Photovoltaic System Interfaced with Artificial Intelligence based Modified Universal Power Quality conditioning system

Unified Power Quality Compensators (UPQC) in load side utility system is not able to fully suppress harmonies in power grid and distortion in the interface system. To enhance the operation of the UPQC, a Fuzzy based Modified Universal power quality conditioning system (Fuzzy-MUPQCS) is developed. Modified Universal power quality conditioning system (MUPQCS) is a combination of two active filters in series and one active filter in shunt. A 3φ voltage source inverter is also used to maintain a common DC link capacitor voltage through Photo voltaic (PV) system connected to a utility grid. Highest Power Point Tracking (HPPT) algorithm is mainly used to pull out the maximum amount of power in the PV system. In this paper, Proportional integral controller based MUPQCS (PI- MUPQCS) and Fuzzy-MUPQCS are used to analyse the load voltage and load current distortion, THD analysis, power factor measurement, grid voltage and grid current distortion in the three phase system under nonlinear load conditions. The execution of the MUPQCS based 3φ system and the controllers are simulated using Matlab /Simulink model.

Volatilization of Standalone Dicamba and Dicamba Plus Glyphosate as Function of Volatility Reducer and Different Surfaces

Dicamba is a herbicide with a moderate volatility profile. Such volatility behavior can be significantly diminished with formulation technology and volatilization reducers. The objective of this study was to quantify the volatility potential of dicamba diglycolamine salt (DGA) in a standalone application or in tank mixture with glyphosate (potassium salt) (GK), with and without volatilization reducer (acetic acid—VaporGrip®) from different surfaces. The combination of these products was applied on four different surfaces (glass slides, corn straw, and dry and moist sandy soil) with three replications, and the experiment was duplicated. The application was performed indoors with an automated sprayer. After application, targets were positioned in cartridges containing two filters in series. Cartridges were placed in a vapor collection system that consisted of a chromatographic oven with constant temperature of 40 °C attached to a vacuum pump for 24 h. After this period, liquid samples were obtained from an extraction procedure of filters and surfaces, which corresponded to the volatilized and deposited portions of the herbicides, respectively. The samples were analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS). The use of this method provided a rapid and consistent evaluation, in which the treated surface exerts a direct influence on the amount of volatilized dicamba. The mixture of dicamba and glyphosate solutions exhibited different volatility profiles as a function of the treated surfaces. The DGA applied alone had the largest level of volatility when applied on moist soil and the lowest level of volatility in dry soil and straw. The DGA with GK had volatilities similar in dry soil, wet soil and straw. The volatility reducer in the tank mixture was effective in reducing DGA dicamba volatilization, regardless of the sprayed surface and the tank mixture, making the application of dicamba safer from the volatilization standpoint.

Assessment of low-cost cartridge filters for implementation in household drinking water treatment systems

In regions where houses are sparsely located, traditional centralized water treatment plants are not economically feasible, with household water treatment (HWT) systems commonly used to provide potable water for a range of household activities. Filtration prior to disinfection is essential, and due to their ease of use and small footprint, cartridge filters are commonly employed. In this work, readily available commercial filter types (spun, wound and pleated) of different micron ratings (10, 5 and 1) were tested for the removal of turbidity either alone or in series via simulated large volume pilot trials. Water with an initial turbidity of 40 ± 10 NTU was prepared using fine test dust (ISO 12103-1, A2) with the turbidity removal efficiency, pressure drop, total capacity and lifespan of the filters evaluated.To increase useable filter lifetime upon reaching the 1 bar pressure limit, a series of washing steps were employed to regenerate the filters. Whilst pleated filters could be efficiently cleaned, spun and wound filters could not, and were discarded after single use. In pilot trials, the volume of turbid water filtered varied from 0.85 m3 with a 1 micron wound filter to 6 m3, with 5 and 1 micron pleated filters in series, which following regeneration could be used for three filtration cycles. For pleated filters, turbidity removal efficiency improved over time as a cake built up resulting in the effluent turbidity reaching acceptable quality (<5 NTU). This criterion continued to be achieved with repeated cycles of washed pleated filters, thereby significantly reducing the cost and improving sustainability of the HWT system. Field trials were carried out with a similar HWT system (5 and 1 micron spun filters) installed in households of rural communities in Curiti, Colombia. Turbidity was effectively removed from natural water (reduction to <1.2 NTU) with improved efficacy in comparison to synthetic water samples due to the large particle size distribution observed in the natural water.

Mitigation of power quality issues using UPQC

Abstract Power quality has become major concern these days due to application of power electronic devices. Conventional equipment like passive filter, segregate series and shunt filters and synchronous condenser etc. have become inadequate to mitigate different power quality problems. Since, power quality mainly concerned with voltage quality and the current quality in the system. For voltage quality, series compensator is used and for current quality, shunt compensator is used. Further, when these two power quality problems are mitigated simultaneously, the device, which is used, called unified power quality conditioner (UPQC), in power distribution system. In this paper voltage related power quality problems such as (voltage sag, voltage swell, voltage and current distortion) are discussed and UPQC controller is simulated to mitigate these problems. There are different control techniques available for UPQC. Here one of them i.e., unit vector template generation (UVTG) is used to simulate UPQC controller. The considered system efficiently regulated the DC link voltage using properly tuned PI parameters. The proposed work is also validated using experimental results.

Reliable Real-Time Output Gap Estimates Based on a Modified Hamilton Filter

We propose a simple modification of Hamilton’s time series filter that yields reliable and economically meaningful real-time output gap estimates. The original filter relies on 8 quarter ahead forecast errors of a simple autoregression of real GDP. While this approach yields a cyclical component that is hardly revised with new incoming data due to the one-sided filtering approach, it does not cover typical business cycle frequencies evenly, but mutes short and amplifies medium length cycles. Further, as the estimated trend contains high-frequency noise, it can hardly be interpreted as potential GDP. A simple modification based on the mean of 4 to 12 quarter ahead forecast errors shares the favorable real-time properties of the Hamilton filter, but leads to a much better coverage of typical business cycle frequencies and a smooth estimated trend. Based on output growth and inflation forecasts and a comparison to revised output gap estimates from policy institutions, we find that real-time output gaps based on the modified and the original Hamilton filter are economically much more meaningful measures of the business cycle than those based on other simple statistical trend-cycle decomposition techniques, such as the HP or bandpass filter, and should thus be used preferably.

Application of horizontal series filtration in greywater treatment: a semi-industrial study

ABSTRACT One of the important alternative water sources for non-potable purposes is greywater, but needs to remove contaminants. The aim of this study was to investigate the performance of a horizontal series filter (HSF) consists of sand, zeolite (Z), pumice (P), and granular activated carbon (GAC) to analyse the chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total dissolved solids (TDS), turbidity, and pH in greywater samples from Fasa University Student Hostel, Iran. Recycling treatment was performed by passing the greywater through filters. After the last filter, treated greywater was returned into the main tank. The system was run at filtration rate of 2.94 m3 day−1. The analysis of the data from the filtration tests showed that GAC is the best adsorbent for removing COD, BOD5, and TDS from greywater, followed by zeolite. Whereas, pumice is more advisable to remove turbidity. However, due to the different mass of adsorbents in the filters, pumice showed a higher adsorption capacity than zeolite. Generally, the triple combination of GAC+Z + P represented the best performance in the reduction of COD, BOD5, TDS, turbidity up to 90.42%, 91.43%, 82.95%, and 90.27%, respectively. Therefore, the studied system can be implemented in public places to greywater treatment and reuse.

Adaptive Fuzzy Logic Control of Hybrid, Active Power Filters, for Harmonic Mitigation

In industrial applications which include power systems, it notices that, harmonics which generated due to nonlinear load (power electronic switches) cause issues for the power quality. Generally, the rectifiers accounted as one of the main elements which produce currents harmonics, where these harmonics will transmit through power system and the generated harmonic distortion will be led to enormous issue and damage for the equipment’s. This study deals with hybrid active filter that consist of shunt active power filter(APF) and passive power filter(PPF) in series with grid based on the instantaneous active and reactive current component (id–iq) control strategy to calculate the reference signal of compensation current which is needed to cancelled the non-linear load current. Furthermore, this new technique method handles with adaptive fuzzy logic control with proportional integral control(PI) to obtain perfect controllable dc input of the inverter across capacitor. Therefore, ac output voltage of active power filter with assist of passive power filter is the desirable value in magnitude and frequency, this led to achieve a perfect attenuation of harmonics, where both harmonics and reactive power are compensating. The simulation results show that, the new control method is very effective to reduce harmonic and improve power quality.

General rational approximation of Gaussian wavelet series and continuous‐timegm‐C filter implementation

SummaryA general method of rational approximation for Gaussian wavelet series and Gaussian wavelet filter circuit design with simplegm‐C integrators is presented in this work. Firstly, the multiorder derivatives of Gaussian function are analyzed and proved as wavelet base functions. Then a high‐accuracy general approximation model of Gaussian wavelet series is constructed, and the transfer function of first‐order derivative of Gaussian wavelet filter is obtained using quantum differential evolution (QDE) algorithm. Thirdly, as an example, a fifth‐order continuous‐time analog first‐order derivative of Gaussian wavelet filter circuit is designed based on multiple loop feedback structure with a simplegm‐C integrator as the basic blocks. Finally, simulation results demonstrate that the proposed method is an excellent way for the wavelet transform implementation. The designed first‐order derivative of Gaussian wavelet filter circuit operates from a 0.53‐V supply voltage and a bias current 2.5 nA. The power dissipation of the wavelet filter circuit at the basic scale is 41.1 nW. Moreover, the high‐accuracy QRS detection based on the designed wavelet filter has been validated in application analysis.