Zeitschriftenartikel: „Voltage filtration“

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Szymański, Jerzy Ryszard, und Marta Żurek-Mortka. „Ground Leakage Current Caused by Common-Mode Voltage of PWM inverter“. Journal of Civil Engineering and Transport 1, Nr. 1 (31.01.2020): 15–25. http://dx.doi.org/10.24136/tren.2019.002.

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In railway tractive vehicles, three-phase PWM (Pulse Width Modulation) inverters generate parasitic Differential-Mode Voltages (DMV) and Common-Mode Voltages (CMV). Parasitic voltages are a side effect of using the width modulation to shape the phase-to-phase inverter’s voltage. In this article, the authors present a mathematical description of the DM and CM voltages and carry out their spectral analysis. Based on the spectral harmonics analysis, the authors present a method for filtration of harmonics of DM and CM voltages aimed at limiting the capacitance parasitic currents: due to DM voltage – phase-to-phase parasitic current and CM voltage – ground parasitic currents. As the final result of the tests, almost complete elimination of leakage parasitic current form PE shock protection system was achieved.

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Abouelatta, Mohamed Anwar, und Abdelhadi R. Salama. „An Equivalent Electrode System for Efficient Charging of Filtration Media“. Indonesian Journal of Electrical Engineering and Computer Science 3, Nr. 3 (01.09.2016): 646. http://dx.doi.org/10.11591/ijeecs.v3.i3.pp646-654.

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This paper concerns the influence of moving an auxiliary limiting cylinder in X-Y directions on the electrostatic field and corona onset voltage of the dual electrode system employed in the electrostatic filtration process resulting in a “Tri-electrode” system. The Tri-electrode system is applied in order to control the field around the ionized wire and on the ground plate. Accurate calculation of the electrostatic field is obtained using the charge simulation method coupled with genetic algorithms. The calculated field values are utilized in computing the corona onset voltage of the ionized electrode. Laboratory measurements of the onset voltage of the ionized electrode are applied. It is found that the limiting cylinder controls the onset voltage of the ionized wire such that the ionized wire may be in ionized or non-ionized state without changing the position of the ionized wire itself. The numerical onset voltage values agreed satisfactorily with those measured experimentally.

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Zhao, Jin Yu, Zhao Lin Liu und Ju Chuan Shan. „Tunable Fabrication of Electrospun Polyvinyl Alcohol Nanofibrous Membrances for Effective Air Filtration“. Key Engineering Materials 748 (August 2017): 423–27. http://dx.doi.org/10.4028/www.scientific.net/kem.748.423.

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Polyvinyl alcohol (PVA) nanofibrous membrances for effective air filtration were fabricated by electrospinning. Tunable fiber morphologies can be formed by facilely regulating the solution concentration and the applied voltage, and their effect on filtration performance of the PVA membrances were also investigeted. Results show that the PVA membrance exhibits high filtration efficiency of 97.1% and low pressure drop of 113 Pa when the PVA concentration is 8 wt% and the applied voltage is 15 kV with a tip-to-collector distance of 15 cm and a feed rate of 1 ml/h.

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Jiang, Ting Ting, Wei Min Kang und Bo Wen Cheng. „Preparation and Characterization of Electrospun CPVC Nanofiber Nonwovens“. Advanced Materials Research 557-559 (Juli 2012): 456–59. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.456.

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In this paper, the chlorinated poly (vinyl-chloride) (CPVC) nanofiber were successfully prepared via electrospinning of the proper spinning solution, which was obtained by dissolving CPVC granules in N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) mixture. The results indicates that the morphology of the fibers is influenced by solution concentration and applied voltage. The finer and uniform nanofiber is electrospun from total solid content of the spinning solutions at 16wt.% and the spinning voltage at 26kV. The surface potential of CPVC nanofiber nonwovens increases with the spinning voltage and the filtration efficiency increases firstly and then decreases. In spinning voltage of 26 kV, filtration efficiency reaches a maximum of 99.925%.

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Ahne, Joerg, Qinghai Li, Eric Croiset und Zhongchao Tan. „Electrospun cellulose acetate nanofibers for airborne nanoparticle filtration“. Textile Research Journal 89, Nr. 15 (28.10.2018): 3137–49. http://dx.doi.org/10.1177/0040517518807440.

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Reported in this paper are the effects of tip-to-collector distance, voltage, deposition time and solution concentration on the fiber size distribution and filter quality factor of electrospun cellulose acetate (CA)-based nanofibers. Nanofibrous filter samples were produced by electrospinning in a laboratory setting. The CA solutions were prepared by diluting various concentrations of CA in a 2:1 (w:w) ratio of N,N-dimethylacetamide (concentration 10–20 wt.%). The electrospinning voltages ranged from 8–12 kV, with distances from 10–15 cm and deposition times of up to 30 minutes. The produced nanofibrous filter samples were then analyzed in terms of fiber size distribution and filter quality factor using nanosized sodium chloride particles ranging from 4–240 nm in diameter. The maximum filtration efficiency measured was 99.8% for filter samples obtained with an overall deposition time of 30 minutes. The maximum filter quality factor was 0.14 Pa−1 for a CA concentration of 20 wt.% and a tip-to-collector distance of 15 cm. The average fiber diameters of the fibers were between 175 and 890 nm, and CA concentrations below 15% led to the formation of beads.

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Wei, Liang, Hongnan Zhang und Xiaohong Qin. „Fabricated narrow diameter distribution nanofiber for an air filtration membrane using a double rings slit spinneret“. Textile Research Journal 89, Nr. 6 (21.02.2018): 936–47. http://dx.doi.org/10.1177/0040517518758009.

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A needleless electrospinning setup called “Needleless Double Rings Slit Electrospinning” was proposed for the first time. The control pump transports solution to the double rings slits through an insulated infusion tube. High voltage is applied to the metal ring and electric force exceeds the surface tension and viscosity, and multiple jets are spontaneously formed on the top of solution surface. Different spinning process parameters, including solution concentration, applied voltage, collection distance and spinning time, have an influence on nanofiber diameter distribution. The morphology of nanofibers has been observed using scanning electron microscopy. It is worth noting that narrow diameter distribution nanofibers have been fabricated using a novel double rings slit spinneret. Nanofiber diameter distribution has determined the mean pore diameter, pore diameter distribution, filtration efficiency and filtration resistance. The final results show that the pore size and filtration property for nanofiber membranes are significantly related with nanofiber diameter distribution. Narrow diameter nanofibers have contributed to the improvement of filtration properties for nanofiber membranes.

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Singh, Alka. „Performance Analysis of a Shunt Compensator Controlled Using Modified Synchronous Reference Theory“. Advances in Electrical Engineering 2014 (07.08.2014): 1–10. http://dx.doi.org/10.1155/2014/392187.

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This paper deals with the control of distribution energy resource (DER) connected to a grid connected system feeding nonlinear loads. The DER is controlled to provide power quality improvement capabilities, namely, power factor correction, harmonic reduction, and load balancing. The developed controller is based on modification of synchronous reference theory. It possesses unique features such as filtration and fundamental voltage extraction from the polluted grid voltages to eliminate harmonics and unbalance. Additionally, the control is implemented over the square of DC link voltage. The distributed generation source is realized as a voltage source converter. Both simulation and experimental results prove the effectiveness of control algorithm with nonlinear loads. The control algorithm works well for power factor correction, harmonic reduction, and operation under unbalanced load condition. The dynamics of the system under load change and load unbalancing are well depicted.

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Aliabadi, Majid. „Effect of electrospinning parameters on the air filtration performance using electrospun polyamide-6 nanofibers“. Chemical Industry and Chemical Engineering Quarterly 23, Nr. 4 (2017): 441–46. http://dx.doi.org/10.2298/ciceq160509059a.

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Due to their high filtration efficiency and low basis weight nanofibrous filters are suitable for filtration applications. The objective of this study was to investigate the effect of electrospinning parameters including polymer solution concentration (10-15 wt.%), applied voltage (15-25 kV) and tip-collector distance (7.5-12.5 cm) on the filtration efficiency of polyamide (PA) nanofibers. The morphology of the PA nanofibers was characterized using scanning electron microscope (SEM) analysis. The SEM image results indicated that the average fiber diameter of PA nanofibers was 220 nm at PA solution concentration of 12.5 wt.%, applied voltage of 20 kV, tip-collector distance of 10 cm, flow rate of 0.5 mL h-1, temperature of 25 ?C and humidity of 40%. The obtained results showed that the highest quality factor and efficiency of 7.02?10-2 Pa-1 and 96% were optimal parameters for nanofibrous filters during 30 and 240 min of electrospinning time, respectively. The presented study showed that the morphology optimization of nanofibers is an effective method for improvement of filtration performance.

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Xin, Baomin, und Milton L. Lee. „Voltage programming in capillary electrochromatography“. Journal of Microcolumn Separations 11, Nr. 4 (1999): 271–75. http://dx.doi.org/10.1002/(sici)1520-667x(1999)11:4<271::aid-mcs4>3.0.co;2-#.

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Abukhanafer, Ghassan, Alaa H. Al-Fatlawi und Hassan H. Joni. „Effect of Pulse Electric Field on Water Characteristics as a Disinfection Function in Filtration Unit“. Engineering and Technology Journal 39, Nr. 1A (25.01.2021): 116–22. http://dx.doi.org/10.30684/etj.v39i1a.1632.

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This paper studied the impact of the addition of pulse electric-filed low voltage (PEF-LV) in the filtration process by designing, constructing, and operating a pilot-scale. The Disinfectant process (DP) demonstrated several benefits in terms of efficiency and ease of application, without the use of any chemical additive. This system contains two pairs of silver mesh electrodes inside the filtration column test with a low pulse voltage for killing microorganisms. The parametric effects of DP performance, such as alternating current pulse frequency and the voltage applied were investigated. The effect of PEF-LV on the biological, physical, and chemical characteristic of water was studied. The transmission electron microscopy (TEM) was used to examine the change of the cell wall morphology of Escherichia coli, Staphylococcus aureus cells for influent, and treated water. The results show the removal efficiency of E. coli and S. aureus 96 % at 30 V and 0.5 Hz.

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Feng, Qiao Ling, und Hua Zhang. „Design of an Electronic Voltage Transformer Suitable for Digital Transformer Substation“. Applied Mechanics and Materials 182-183 (Juni 2012): 665–69. http://dx.doi.org/10.4028/www.scientific.net/amm.182-183.665.

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In this paper an electronic voltage-current voltage transformer (EVCVT) scheme has been proposed based on voltage-current transformation, using the voltage - current transformation technology and weak current detection technology to achieve the accurate measurement of the grid voltage. It transforms the high voltage into low current by high voltage thick film resistor, then the current sensor transforms the low current signal into a standard analog voltage signal, thus an AD converter collects the voltage signal, and the value be imported into the microprocessor for filtration, calibration, coding. After filtering the data would be transmitted to the upper computer or relay protection devices of the digital substation. This paper focused on the design of hardware circuit of digital voltage transformer, developed the software package and produced a prototype control board. Initial experiments show that the scheme is valuable for digital substation.

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Schreuder-Gibson, Heidi L., Phil Gibson und Peter Tsai. „Cooperative Charging Effects of Fibers from Electrospinning of Electrically Dissimilar Polymers“. International Nonwovens Journal os-13, Nr. 4 (Dezember 2004): 1558925004os—13. http://dx.doi.org/10.1177/1558925004os-1300406.

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Electrical charging and residual charge decay of electro-spun nonwoven webs comprised of two electrically dissimilar polymers were studied in an effort to investigate their filtration properties. Polystyrene (PS) and polyacrylonitrile (PAN) were electrospun separately, in a layer-by-layer configuration and simultaneously in a side-by-side bi-component apparatus into thin webs on a polypropylene spunbond substrate. During electrospinning of the PS and PAN polymer solutions, the fibers became positively charged when positive voltage was applied to the solution-filled spinning nozzle and became negatively charged when negative voltage was applied. This study was undertaken to examine the effect of cooperative charging from electrospinning of the two polymers, the effect of the three types of web constructions on charge retention, and filtration properties of the fibers. It was found that single, multilayered, and bi-component webs retained surface charges in the thousands of volts that diminished very little over a 20-hour period, but eventually bled off while resting for three months. Filtration properties were found to be exceptionally high for some, but not all, electrospun samples; filtration was found to have a weak dependence on both surface charge and web geometrical factors, particularly the fiber diameter, that influence pressure drop of the aerosol test.

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Lou, Ching-Wen, Ying-Huei Shih, Chen-Hung Huang, Shu-An Lee, Yueh-Sheng Chen und Jia-Horng Lin. „Filtration Efficiency of Electret Air Filters Reinforced by Titanium Dioxide“. Applied Sciences 10, Nr. 8 (13.04.2020): 2686. http://dx.doi.org/10.3390/app10082686.

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In this study, titanium dioxide (TiO2), a mineral with a potential and supercapacitor, is used as the reinforcing material to improve the filtration efficacy of electret melt-blown fabrics. Next, the electret melt-blown fabrics are evaluated in terms of surface voltage and filtration efficiency, thereby examining the influences of the TiO2 ratio and electric field intensity. The test results indicate that the filtration efficiency is proportional to the ratio of TiO2 and electric field intensity. In particular, with a TiO2 ratio of 3 wt% and an electric field intensity of 2.5 kV/cm, the electret melt-blown fabrics demonstrate a maximal filtration efficiency of 96.32%, a lowest pressure drop of 40 Pa, and an optimal quality factor of 0.083 Pa−1.

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Artemenko, M. Yu, Y. V. Kutafin, V. M. Mykhalskyi, S. Y. Polishchuk, V. V. Chopyk und I. A. Shapoval. „SHUNT ACTIVE FILTER CONTROL OF A THREE-PHASE THREE-WIRE NETWORK IN THE COORDINATE SYSTEM OF THE TWO WATTMETERS METHOD“. Tekhnichna Elektrodynamika 2021, Nr. 5 (16.08.2021): 11–20. http://dx.doi.org/10.15407/techned2021.05.011.

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A combined control system for a shunt active filter in the coordinate system of the two-wattmeters method has been proposed, which, depending on the conditions of use, implements one of the four active filtration strategies, optimal according to a certain quality indicator. The most promising is the proposed integral strategy for active filtration control with the reference vector of line voltages of direct sequence, which provides symmetric sinusoidal currents of the network and the minimum pulsation of power consumption for the almost identical energy-saving effect as the concept of S. Fryze. New formulas for calculating the energy-saving effect and pulsations of the instantaneous power in a three-phase system of power in the case of the formation of an active current in the transmission line in the conditions of asymmetry of loading voltage and linear asymmetric load have been developed. Simulation studies have confirmed the adequacy of the proposed strategies and calculations. References 15, figures 5, tables 2.

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STOCKAND, JAMES D., und STEVEN C. SANSOM. „Glomerular Mesangial Cells: Electrophysiology and Regulation of Contraction“. Physiological Reviews 78, Nr. 3 (07.01.1998): 723–44. http://dx.doi.org/10.1152/physrev.1998.78.3.723.

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Stockand, James D., and Steven C. Sansom. Glomerular Mesangial Cells: Electrophysiology and Regulation of Contraction. Physiol. Rev. 78: 723–744, 1998. — Mesangial cells are smooth muscle-like pericytes that abut and surround the filtration capillaries within the glomerulus. Studies of the fine ultrastructure of the glomerulus show that the mesangial cell and the capillary basement membrane form a biomechanical unit capable of regulating filtration surface area as well as intraglomerular blood volume. Structural and functional studies suggest that mesangial cells regulate filtration rate in both a static and dynamic fashion. Mesangial excitability enables a homeostatic intraglomerular stretch reflex that integrates an increase in filtration pressure with a reduction in capillary surface area. In addition, mesangial tone is regulated by diverse vasoactive hormones. Agonists, such as angiotensin II, contract mesangial cells through a signal transduction pathway that releases intracellular stores of Ca2+, which subsequently activate nonselective cation channels and Cl− channels to depolarize the plasma membrane. The change in membrane potential activates voltage-gated Ca2+ channels, allowing Ca2+ cell entry and further activation of depolarizing conductances. Contraction and entry of cell Ca2+ are inhibited only when Ca2+-activated K+ channels (BKCa) are activated and the membrane is hyperpolarized toward the K+ equilibrium potential. The mesangial BKCa is a weak regulator of contraction in unstimulated cells; however, the gain of the feedback is increased by atrial natriuretic peptide, nitric oxide, and the second messenger cGMP, which activates protein kinase G and decreases both the voltage and Ca2+ activation thresholds of BKCa independent of sensitivity. This enables BKCa to more effectively counter membrane depolarization and voltage-gated Ca2+ influx. After hyperpolarizing the membrane, BKCa rapidly inactivates because of dephosphorylation by protein phosphatase 2A. Regulation of ion channels has been linked casually to hyperfiltration during early stages of diabetes mellitus. Determining the signaling pathways controlling the electrophysiology of glomerular mesangial cells is important for understanding how glomerular filtration rate is regulated in health and disease.

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Jiang, Yingchang, Zeyi Wu, Le Jiang, Zhichang Pan, Peiyu Yang, Wenchao Tian und Linfeng Hu. „Freestanding CoSeO3·H2O nanoribbon/carbon nanotube composite paper for 2.4 V high-voltage, flexible, solid-state supercapacitors“. Nanoscale 10, Nr. 25 (2018): 12003–10. http://dx.doi.org/10.1039/c8nr02924e.

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Freestanding paper consisting of ultrathin CoSeO₃·H₂O nanoribbons and carbon nanotubes fabricated by a vacuum-assisted filtration strategy exhibits 2.4 V high-voltage, high energy density and excellent flexibility for solid-state supercapacitors.

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Tarasiuk, Tomasz. „Simple methods of voltage dip tracking– case study“. ACTA IMEKO 6, Nr. 4 (28.12.2017): 80. http://dx.doi.org/10.21014/acta_imeko.v6i4.316.

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The paper presents results of an experimental study of two methods of voltage dip tracking. The first is based on half cycle absolute peak value monitoring, whereas the second is based on low-pass filtration of squares of voltage samples. Both methods are devised for application in low-cost integrated circuits, dedicated to power quality monitoring. The two real voltage dips have been considered for the aim. The results are compared with the reference method recommended in IEC Std. 61000-4-30, based on calculation of the r.m.s. voltage refreshed each half cycle. Further, the application of the low-pass method for assessment small voltage variations is considered, both short term (r.m.s. voltage refreshed each half cycle) and long term (r.m.s. voltage calculated over 10 cycles of voltage fundamental component). The research confirmed sufficient accuracy of the method based on low-pass filtering for the class A of measurement.

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Kitagawa, Shinya, und Takao Tsuda. „Pulsed voltage induced injection for capillary liquid chromatography“. Journal of Microcolumn Separations 12, Nr. 5 (2000): 285–91. http://dx.doi.org/10.1002/(sici)1520-667x(2000)12:5<285::aid-mcs2>3.0.co;2-s.

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Alam, Iftaykhairul, Linda M. Guiney, Mark C. Hersam und Indranil Chowdhury. „Application of external voltage for fouling mitigation from graphene oxide, reduced graphene oxide and molybdenum disulfide functionalized surfaces“. Environmental Science: Nano 6, Nr. 3 (2019): 925–36. http://dx.doi.org/10.1039/c8en01222a.

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Pullano, Salvatore A., Antonino S. Fiorillo, Gianluca Barile, Vincenzo Stornelli und Giuseppe Ferri. „A Second-Generation Voltage-Conveyor-Based Interface for Ultrasonic PVDF Sensors“. Micromachines 12, Nr. 2 (20.01.2021): 99. http://dx.doi.org/10.3390/mi12020099.

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Exploiting the transmission and reception of low frequency ultrasounds in air is often associated with the innate echolocating abilities of some mammals, later emulated with sophisticated electronic systems, to obtain information about unstructured environments. Here, we present a novel approach for the reception of ultrasounds in air, which exploits a piezopolymer broadband sensor and an electronic interface based on a second-generation voltage conveyor (VCII). Taking advantage of its capability to manipulate both voltage and current signals, in this paper, we propose an extremely simple interface that presents a sensitivity level of about −100 dB, which is in line with commercially available references. The presented results are obtained without any filtration stage. The second-generation voltage conveyor active device is implemented through a commercially available AD844, with a supply voltage of ±15 V.

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Loginov, M., N. Lebovka, O. Larue, M. Shynkaryk, M. Nonus, J. L. Lanoisellé und E. Vorobiev. „Effect of high voltage electrical discharges on filtration properties of Saccharomyces cerevisiae yeast suspensions“. Journal of Membrane Science 346, Nr. 2 (Januar 2010): 288–95. http://dx.doi.org/10.1016/j.memsci.2009.09.048.

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Su, Weiyin, Lanfeng Hui, Xiaoyan Ma, Qian Yang und Wanhong Sun. „Filtration efficiency improvement of air filter paper for fine particles by electrospinning technology“. BioResources 16, Nr. 3 (01.06.2021): 5220–33. http://dx.doi.org/10.15376/biores.16.3.5220-5233.

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Due to great advantages, such as simple operation, high porosity, and good fiber continuity, the working principle and research progress of electrospinning technology was studied and polyvinyl alcohol (PVOH) nanofibers were prepared via this process. Air filter paper was used as the receiving substrate to prepare electrospun nano air filter paper (NAFP). The PVOH concentration, static voltage, and receiving distance, were tested to explore the influence of spinning parameters on the filtration performance. Further, the microfiber morphology of the electrospun NAFP was observed. The performance of filter paper, including air permeability, pore size, initial resistance, filtration efficiency, and dust retention, were tested. The results showed that the electrospun NAFP had better filtration performance compared to the air filter paper, and simultaneously they had lower initial resistance and higher precision filtration efficiency. The nanofiber influenced the surface of the air filter paper, as it sharply reduced the pore size. When the spinning condition was 10%, 21 kV, and 15 cm, the pore size decreased approximately 0.6 times of the original, which meant the electrospun NAFP could capture particles ≥ 0.2 μm in size. Finally, after three repeated uses, the good filtration performance was maintained.

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McCarthy, Dean, und Patrick Kenny. „Extended detail contrasts for TO.10 use on flat panel detector fluoroscopy systems“. British Journal of Radiology 94, Nr. 1122 (01.06.2021): 20201422. http://dx.doi.org/10.1259/bjr.20201422.

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Objectives: Leeds Test Object Ten (TO.10) is routinely used to subjectively estimate Threshold Contrast Detail Detectability (TCDD) as a measure of image quality in fluoroscopy. However, manufacturer guidance provides calibrated contrasts for only limited peak voltage and copper filtration thickness combinations. Prescribed testing conditions are often difficult to attain as modern flat panel fluoroscopic systems independently determine voltage and copper filtration thickness settings. This work aims to extend the range of TO.10 contrasts available for routine testing at peak voltage and copper thickness settings likely to be encountered. Methods: Two methods are described for generalising the calculation of target contrasts: a three-dimensional interpolation/extrapolation model in MATLAB®, and a multivariate log-polynomial function. Both methods utilise the available calibrated contrasts to estimate contrasts at voltage and copper thickness combinations routinely encountered. Results: Results are presented as Threshold Detection Index [Formula: see text] curves fit by a second-order polynomial of log [Formula: see text] to log [Formula: see text] . Results are found to be more accurate at unprescribed conditions while also reproducible for relatively consistent input air kerma rate (IAKR) expected from automatic dose rate controls (ADRC). Conclusions: The calculation of TO.10 contrasts at non-standard conditions aids in the determination of an absolute estimate of image quality in fluoroscopy with greater accuracy, reproducibility and efficiency. Advances in knowledge: TO.10 detail contrasts for TCDD testing of fluoroscopy units have been significantly extended beyond those previously available. The described methods will aid the clinical physicist in absolute assessments of fluoroscopic image quality and facilitate inter system comparisons.

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CRISTINA, BANCIU, BĂRA ADELA, CHIȚANU ELENA, MARINESCU VIRGIL, SBÂRCEA GABRIELA und ION IOANA. „The effect of process parameters on the electrospun polystyrene fibers“. Industria Textila 69, Nr. 04 (01.09.2018): 263–69. http://dx.doi.org/10.35530/it.069.04.1481.

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Electrospinning is one of the methods for obtaining nano/microfibers, using polymeric solutions. These nanofibrous membranes are highly porous with interconnected pores, having high specific surface area and small pore size, making them a suitable candidate for filtration applications. The properties of electrospun fibers are influenced by polymer solution, solvent, solution concentration, viscosity, electrical conductivity, electrical voltage, spinneret to collector distance etc. Expanded polystyrene is a polymeric product that is usually used for insulation and packaging. Recycling expanded polystyrene into nanofibers with applications in filtration could be useful from an economic point of view. The purpose of this study was to investigate the influence of expanded polystyrene polymer solution characteristics (concentration, viscosity) and the process parameters (applied voltage, distance between the tip and the collector plate, flow rate of the polymer solution) on the morphology and the properties of the obtained electrospun fibers. Therefore, three EPS solutions with 10, 15 and 20% wt. concentration were prepared and were electrospun under processing conditions with an applied voltage of 12, 15 and 18 kV, a spinneret-to-collector distance of 20 cm, a flow rate of solution of 1.5 and 2 mL/hour, a spinneret diameter of 0.8 mm and stationary copper substrate. The morphology of the electrospun fibers was observed by scanning electron microscopy. The mechanical properties were evaluated by tensile strength and elongation tests.

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Dibona, Gerald F., und Linda L. Sawin. „Functional significance of the pattern of renal sympathetic nerve activation“. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 277, Nr. 2 (01.08.1999): R346—R353. http://dx.doi.org/10.1152/ajpregu.1999.277.2.r346.

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To assess the renal functional significance of the pattern of renal sympathetic nerve activation, computer-generated stimulus patterns (delivered at constant integrated voltage) were applied to the decentralized renal sympathetic nerve bundle and renal hemodynamic and excretory responses determined in anesthetized rats. When delivered at the same integrated voltage, stimulus patterns resembling those observed in in vivo multifiber recordings of renal sympathetic nerve activity (diamond-wave patterns) produced greater renal vasoconstrictor responses than conventional square-wave patterns. Within diamond-wave patterns, increasing integrated voltage by increasing amplitude produced twofold greater renal vasoconstrictor responses than by increasing duration. With similar integrated voltages that were subthreshold for renal vasoconstriction, neither diamond- nor square-wave pattern altered glomerular filtration rate, whereas diamond- but not square-wave pattern reversibly decreased urinary sodium excretion by 25 ± 3%. At the same number of pulses per second, intermittent stimulation produced faster and greater renal vasoconstriction than continuous stimulation. At the same number of pulses per second, increases in rest period during intermittent stimulation proportionally augmented the renal vasoconstrictor response compared with that observed with continuous stimulation; the maximum augmentation of 55% occurred at a rest period of 500 ms. These results indicate that the pattern of renal sympathetic nerve stimulation (activity) significantly influences the rapidity, magnitude, and selectivity of the renal vascular and tubular responses.

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Ahn, Young Chull, Jae Ik Cho, Si Eun Kim, Ah Hee Jeong und Gil Tae Kim. „Development and Evaluation of Nano Electret Filters for Household Water Treatment“. Applied Mechanics and Materials 493 (Januar 2014): 767–72. http://dx.doi.org/10.4028/www.scientific.net/amm.493.767.

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Korea is expected to one of countries with water shortages, and thus must secure high-quality water resources and strictly maintain them. However, water is frequently polluted and there is still a lack of water treatment technologies and facilities to provide safe water. To remove pollutants, membrane-based methods are being widely used for water treatment. It needs high pressure and energy to capture the pollutants by pore size. In this study, electrostatic force is used to increase the efficiency of filtration and decrease pressure loss. By electro spinning, nanoelectret filter is made with 100 nm in diameter and positive charge potential. Surface potential is measured by electrostatic voltmeter system with nanoelectret filter by three conditions of applied voltage. For the filtration performance, filtration efficiency is measured by filter test system with 0.5 and 1.0 PSL. Also pressure loss of nanoelectret filter is measured by comparing PC membrane.

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Söderman, M., B. Hansson und B. Axelsson. „Radiation Dose and Image Quality in Neuroangiography: Effects of Increased Tube Voltage, Added X-Ray Filtration and Antiscatter Grid Removal“. Interventional Neuroradiology 4, Nr. 3 (September 1998): 199–207. http://dx.doi.org/10.1177/159101999800400304.

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During endovascular treatment the patient may be subject to fluoroscopy for long periods as well as multiple x-ray exposures. The radiation dose to the patient can be considerable, and cause local deterministic effects such as alopecia or even skin burn. The potential carcinogenic effects should also be noted, being especially important in the paediatric population. We measured radiation doses to patients and personnel during neuroendovascular procedures and diagnostic neuroangiography. We also tried to reduce the radiation dose to the patient utilising increased tube voltage, additional primary X-ray filtration and by removing the antiscatter grid in front of the image intensifier, employing air gap technique. We investigated radiation doses to patient and personnel during neuroangiographic procedures and optimized the examination technique with regard to radiation dose with maintained image quality. Radiation exposure to patients and personnel was measured with thermoluminescent dosimeters and permanently mounted KermaDose-Area-Product meters in front of the X-ray tubes during 13 cerebral angiographies and six neuroendovascular procedures. We performed experiments with radiation dose measurements and evaluation of image quality with 80 and 90 kV tube voltage during image acquisition and 75 and 85 kV during fluoroscopy, as well as with different primary X-ray filtration. Images from patient studies acquired with the original grid in front of the image intensifier were compared with images from patient studies acquired with the grid removed and air gap technique (30 cm). Images from patient studies acquired with the original examination technique were compared to images from patient studies acquired with increased x-ray tube voltage, increased x-ray filtering and with the antiscatter grid removed using an airgap as scatter reduction method. Radiation exposure to personnel was very low using standard protective devices. Measurable doses were recorded only on the hands and forehead of the neuroradiologist. Maximum entrance skin dose was about 1 Gy on the side of the patientspatient's forehead during an endovascular procedure. Increasing the tube voltage from 75 to 85 – 85 and 90 kV, exchanging the original 0.5 mm aluminium primary filtration for 0.2 mm copper and removing the antiscatter grid allowed us to reduce entrance skin dose to the patient by 70% with unchanged or slightly improved image quality.

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Kus, Vaclav, Bohumil Skala und Pavel Drabek. „Complex Design Method of Filtration Station Considering Harmonic Components“. Energies 14, Nr. 18 (16.09.2021): 5872. http://dx.doi.org/10.3390/en14185872.

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The paper deals with a new methodology for calculating the filter parameters. The basis is respect for the fact that the real filter current consists of other harmonic components, which filter is tuned. The proposed methodology was used to design filters for traction substation 25 kV/50 Hz. The operation of the locomotives in the AC supply systems of 25 kV/50 Hz leads to a rising of higher order harmonic currents. Due to the 1-phase supply system, these are mainly the 3rd and 5th harmonics. By simulation and subsequent measurement of the proposed traction power station filters the proposed methodology was verified. Thus, the filter design can also be used for filter compensating stations of the standard 3-phase distribution network. The described method presents an optimal filter design without unnecessary oversizing. This fact reduces the size and cost of the filter. It is shown that it is possible to design a filter that meets the requirements for power quality under extreme load and to minimise distortion of line voltage.

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Pervianenak, R. E., und A. L. Sitsko. „Phase synchronization in the system of supply voltage parameters correction by the adaptive filtration method“. Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 66, Nr. 2 (16.07.2021): 212–19. http://dx.doi.org/10.29235/1561-8358-2021-66-2-212-219.

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An adaptive phase-locked loop is considered, which makes it possible to improve the stability of synchronous active filters, to achieve compensation for high-quality harmonic components of the current consumed by autonomous objects. Therefore, the use of such an active filter will improve the power quality and the normal trouble-free operation of the equipment in general. A control system with an adaptive phase-locked loop often has the advantages of a reliable and efficient control system. It makes it possible to quickly respond to dynamic changes in the load, which is typical for the operation of functional equipment of autonomous objects. The control system becomes more flexible, reliable, efficient and provides an instantaneous value of the compensation current from the measured values of the load current curve. Calculations can be carried out in real time. LMS, NLMS, RLS algorithms are considered as adjusting the weighted adaptive phase-locked loop in the system for correcting the supply voltage parameters. Based on the simulation of algorithms carried out in the MATLAB environment, a comparative analysis of their effectiveness is made. It is shown that the NLMS algorithm has the highest suppression quality and minimum transient time. The NLMS algorithm works in real time and is recommended for use in the supply voltage correction system.

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Lin, Shiang-Chi, Yu-Lung Sung, Chien-Chung Peng, Yi-Chung Tung und Chih-Ting Lin. „An in-situ filtering pump for particle-sample filtration based on low-voltage electrokinetic mechanism“. Sensors and Actuators B: Chemical 238 (Januar 2017): 809–16. http://dx.doi.org/10.1016/j.snb.2016.07.147.

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31

Shao, Zungui, Jiaxin Jiang, Xiang Wang, Wenwang Li, Liang Fang und Gaofeng Zheng. „Self-Powered Electrospun Composite Nanofiber Membrane for Highly Efficient Air Filtration“. Nanomaterials 10, Nr. 9 (29.08.2020): 1706. http://dx.doi.org/10.3390/nano10091706.

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Highly efficient air filtration with low pressure drop is the key to air purification. In this work, a self-powered electrospun nanofiber membrane with an electrostatic adsorption effect was prepared to improve the filtration efficiency of micro/nano particles. The composite membrane was comprised of polyvinyl chloride (PVC) nanofibers and polyamide-6 (PA6) nanofibers. The triboelectric effect between the two adjacent nanofiber membranes generated electrostatic charges under the action of air vibration, by which the electrostatic adsorption with the same pressure drop was enhanced. The electrostatic voltage on the self-powered nanofiber membrane was 257.1 mV when the flow velocity was 0.1 m/s. For sodium chloride (NaCl) aerosol particles with a diameter of 0.3 μm, the removal efficiency of the self-powered composite nanofiber membrane was 98.75% and the pressure drop was 67.5 Pa, which showed a higher quality factor than the membrane without electrostatic charges. This work provides an effective way to improve the filtration performance of air filter membranes.

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Sabat, M. B., N. G. Maltseva, M. Y. Oliinyk und V. G. Fedishin. „CALCULATION OF CURRENT LOADING OF THREE-PHASE BRIDGE RADIATION IN NON-SUPERMEAL MODES UNDER THE FILTRATION AVAILABILITY“. METHODS AND DEVICES OF QUALITY CONTROL, Nr. 1(42) (27.06.2019): 65–69. http://dx.doi.org/10.31471/1993-9981-2019-1(42)-65-69.

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The curves of the rectified voltage of the non-ventilated modes of the three-phase bridge rectifier circuit have in their composition a number of non-canonical higher harmonics, which results in significant pulsations of the load current. Hence the problem of choosing the optimal composition of filters in order to prove the load current pulsation coefficient to allowable values. The analysis of the current state of the problem is carried out by studying the latest publications. The analytical expressions and forms of load current curves are obtained based on the results of mathematical modeling of the resonant and inductive filters higher harmonics influence on the outputs and rectifier loads, respectively, on the leads and in the rectifier load cell. The value of the current ripple coefficient in the load cell for the individual cases of the non-ventilated mode of the three-phase bridge rectifier is calculated. The curves of the currents given in this article are valid for those forms of rectified voltage that arises in non-blunt modes of the three-phase bridge rectifier scheme, and can be obtained under the condition of a known composition of higher harmonics of the output voltage of the rectifier. It is shown that the establishment of a resonance filter at the frequency of the largest harmonic significantly reduces the current pulsation coefficient in the load cell. In the case of a real resonance filter at the output of the rectifier in the current of the load circuit there will be a harmonic, which will proceed under the action of a voltage drop on the active resistance of the filter. However, its effect will be negligible, since the active resistance of the filters is usually small. The level of harmonic components in the load current will also diminish somewhat as a result of the branching of a certain value of these currents through the branches of the resonant filters. The proposed method allows to calculate the current in the recirculation load cell in non-ventilated modes, taking into account a certain composition of resonant parallel and inductive serial filters to achieve the desired level of current pulsations.

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Lee, Y., und S. W. Oa. „High speed municipal sewage treatment in microbial fuel cell integrated with anaerobic membrane filtration system“. Water Science and Technology 69, Nr. 12 (12.04.2014): 2548–53. http://dx.doi.org/10.2166/wst.2014.179.

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A cylindrical two chambered microbial fuel cell (MFC) integrated with an anaerobic membrane filter was designed and constructed to evaluate bioelectricity generation and removal efficiency of organic substrate (glucose or domestic wastewater) depending on organic loading rates (OLRs). The MFC was continuously operated with OLRs 3.75, 5.0, 6.25, and 9.38 kg chemical oxygen demand (COD)/(m3·d) using glucose as a substrate, and the cathode chamber was maintained at 5–7 mg/L of dissolved oxygen. The optimal OLR was found to be 6.25 kgCOD/(m3·d) (hydraulic retention time (HRT) 1.9 h), and the corresponding voltage and power density averaged during the operation were 0.15 V and 13.6 mW/m3. With OLR 6.25 kgCOD/(m3·d) using domestic wastewater as a substrate, the voltage and power reached to 0.13 V and 91 mW/m3 in the air cathode system. Even though a relatively short HRT of 1.9 h was applied, stable effluent could be obtained by the membrane filtration system and the following air purging. In addition, the short HRT would provide economic benefit in terms of reduction of construction and operating costs compared with a conventional aerobic treatment process.

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Yin, Danfen, Xiaoling Zhang, Xianwei Han, Jun Yang und Ning Hu. „Multi-Stage Particle Separation based on Microstructure Filtration and Dielectrophoresis“. Micromachines 10, Nr. 2 (31.01.2019): 103. http://dx.doi.org/10.3390/mi10020103.

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Particle separation is important in chemical and biomedical analysis. Among all particle separation approaches, microstructure filtration which based particles size difference has turned into one of the most commonly methods. By controlling the movement of particles, dielectrophoresis has also been widely adopted in particle separation. This work presents a microfluidic device which combines the advantages of microfilters and dielectrophoresis to separate micro-particles and cells. A three-dimensional (3D) model was developed to calculate the distributions of the electric field gradient at the two filter stages. Polystyrene particles with three different sizes were separated by micropillar array structure by applying a 35-Vpp AC voltage at 10 KHz. The blocked particles were pushed off the filters under the negative dielectrophoretic force and drag force. A mixture of Haematococcus pluvialis cells and Bracteacoccus engadinensis cells with different sizes were also successfully separated by this device, which proved that the device can separate both biological samples and polystyrene particles.

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Dadić, Martin, Petar Mostarac, Roman Malarić und Jure Konjevod. „Digital Compensation of a Resistive Voltage Divider for Power Measurement“. Electronics 10, Nr. 6 (16.03.2021): 696. http://dx.doi.org/10.3390/electronics10060696.

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The paper presents a method for digital compensation of the ratio and phase angle errors of a resistive voltage divider. The system consists of a separate electrical circuit of a resistive divider, and a digital compensation system based on National Instruments (NI) PCI eXtension for Instrumentation (PXI) PXI-5922 digital acquisition cards (DAQ). A novel approach to the real-time compensation is presented, using digital signal processing. The algorithm is based on Wiener filtering and finite-impulse-response (FIR) filters. The proposed digital compensation, using FIR digital filtration and NI PXI DAQs, gives maximum magnitude error below 400 ppm and the phase angle error below 4500 μrad, in the frequency band 50 Hz–100 kHz. The algorithm allows the fine-tuning of the compensation to adjust to the possible change in the original transfer function due to the aging of the components.

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Matulevicius, Jonas, Linas Kliucininkas, Dainius Martuzevicius, Edvinas Krugly, Martynas Tichonovas und Jonas Baltrusaitis. „Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications“. Journal of Nanomaterials 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/859656.

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Electrospun polyamide 6 (PA 6) and polyamide 6/6 (PA 6/6) nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats) were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol) solutions with the smallest fiber diameters (62–66 nm) had the highest filtration efficiency (PA6/6_30 = 84.9–90.9%) and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1).

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Du, Chunhui, Min Zhang, Qiuyue Huang, Shengdong Zhang und Yang Chai. „Ultralow-voltage all-carbon low-dimensional-material flexible transistors integrated by room-temperature photolithography incorporated filtration“. Nanoscale 11, Nr. 32 (2019): 15029–36. http://dx.doi.org/10.1039/c9nr02511a.

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Low dimensional materials (LDMs) have drawn world-wide attention as potential candidates applied in flexible and wearable electronics. However, integrating all-LDMs to realize independent-operation flexible devices are pretty challenging.

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Xu, Xiaotong, Hanmin Zhang, Tianyu Gao und Jiaheng Teng. „Impacts of applied voltage on forward osmosis process harvesting microalgae: Filtration behaviors and lipid extraction efficiency“. Science of The Total Environment 773 (Juni 2021): 145678. http://dx.doi.org/10.1016/j.scitotenv.2021.145678.

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Hassan, Fatiheea F. „Assessment of X-Ray Tube Technical Factors: Tube Voltage and Exposure Time in Erbil Medical Imaging Centers“. Disease and Diagnosis 9, Nr. 4 (30.12.2020): 144–47. http://dx.doi.org/10.34172/ddj.2020.03.

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Background: An evaluation of certain radiographic factors affecting patient exposure during medical imaging was carried out. Factors considered included selection of tube kilovoltage and time exposure combination. An increase in X-ray tube voltage increases the amount of radiation coming out of the X-ray tube, as well as the amount of skin dose in the image. This study aimed to assess the possibility of reducing the voltage and exposure time in medical imaging centers. The study indeed intended to protect patients from the risk of developing cancer with excessive radiation dose. Materials and Methods: This study was performed in Erbil hospitals, Iraq. NOMEX multimeter (Finland, PTW) was used to measure radiation dose (mGy), total voltage, current (mA), exposure time (s), and total filtration in 150 patients undergoing different X-ray examinations. Results: The results showed that the highest output was obtained in the age group of 42-70 years (dose range: 52.43–19.46 mGy), followed by the age group of 50-70 years (dose range: 39.9–25.63 mGy) and the age group of 10–40 years (dose range: 30.35–10.55 mGy). Conclusion: The high voltage (kVp) and high exposure time to be important factors to increase patient doses via increasing the exposure dose. Thus, optimization of exposure time and voltage is recommended for all cancer patients undergoing medical imaging with high voltage and long exposure time.

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Thayumanavan, Menaka, Andy Srinivasan und Senthil Arumugam. „Correlation model for fiber diameter of electro-spun membrane using KGM (1,N) model for nano-filtration“. Thermal Science, Nr. 00 (2021): 268. http://dx.doi.org/10.2298/tsci210702268t.

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Nanofiltration is an important application for electro-spun fiber as it is well characterized by fine fiber diameter, huge density, high penetrability and flexibility. In this paper, the Poly-acrylonitrile (PAN) fiber diameter is determined experimentally by varying four factors such as voltage, flow rate, the distance between spinneret and collector, and mass fraction in the electrospinning process. The fiber diameter is measured through SEM analysis. A highly accurate kernel-based nonlinear multivariable grey model, KGM (1, 1) model is used for the prediction of nanofiber diameter for filtering particulate less than 500 nm. This is proved to be better when compared to the Grey Model First Order One Variable and Multivariable grey model. Based on simulated outcomes, filtration membranes are prepared and tested for filtration efficiency for the airborne particles relating its air permeability, porosity and quality factor.

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Pan, Yi Jun, Wei Sheng Chuang, Chao Yu Lin und Chun Hua Chu. „Composited Silver-Contained PA 6 Electrospun Fibers with Spunbond Nonwovens for Filtration Applications“. Advanced Materials Research 287-290 (Juli 2011): 2626–29. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.2626.

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By using electrospinning method, polyamide 6 (PA 6) nanofibers containing 1 wt% of AgNo3 were spun from different concentrations solutions (15-25 wt%) for use as composite filter media. The silver ions in PA 6 nanofibers were reduced by ascorbic acid solution to silver particles offering antibacterial properties to the final filter after electrospinning. The results show, fibers with mean diameters less than 160 nm were prepared for use as filter media by electrospinning. The diameter of electrospun fiber was proportioned to the viscosity of PA 6 solution but was inversed to the applied electrical voltage. The viscosities of PA 6 solution were decreased by adding of AgNo3 from which brought more irregular formation of electrospun fibers. The filtration efficiency of spunbond nonwoven would improve greatly by compositing the electrospun PA6 web with or without silver.

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Apfaltrer, Georg, Moritz H. Albrecht, U. Joseph Schoepf, Taylor M. Duguay, Carlo N. De Cecco, John W. Nance, Domenico De Santis et al. „High-pitch low-voltage CT coronary artery calcium scoring with tin filtration: accuracy and radiation dose reduction“. European Radiology 28, Nr. 7 (05.02.2018): 3097–104. http://dx.doi.org/10.1007/s00330-017-5249-2.

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Wang, Qiannan, Farzana Khan, Liang Wei, Henggen Shen, Chuyang Zhang, Qiuran Jiang und Yiping Qiu. „Filtration properties of carbon woven fabric filters supplied with high voltage for removal of PM 1.0 particles“. Separation and Purification Technology 177 (April 2017): 40–48. http://dx.doi.org/10.1016/j.seppur.2016.11.054.

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Tesche, Christian, Carlo N. De Cecco, Rozemarijn Vliegenthart, Moritz H. Albrecht, Akos Varga-Szemes, Taylor M. Duguay, Ullrich Ebersberger et al. „Accuracy and Radiation Dose Reduction Using Low-Voltage Computed Tomography Coronary Artery Calcium Scoring With Tin Filtration“. American Journal of Cardiology 119, Nr. 4 (Februar 2017): 675–80. http://dx.doi.org/10.1016/j.amjcard.2016.10.051.

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Iwański, Grzegorz, Paweł Maciejewski und Tomasz Łuszczyk. „Non-Cartesian Frame Transformation-Based Control of a Three-Phase Power Converter During Unbalanced Voltage Dip – Part I: Transformation Principles“. Power Electronics and Drives 4, Nr. 1 (01.06.2019): 47–61. http://dx.doi.org/10.2478/pead-2019-0013.

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Abstract One of the currently investigated problems in power electronics-based electrical energy conversion is proper operation of electronic converters during grid voltage imbalance and harmonics. In classic control methods, it introduces oscillations of variables, resulting in the necessity to improve control systems with signals filtration and usually by application of resonant terms as part of current controllers. The paper presents a new approach to grid-connected inverter control based on transformation to a non-Cartesian frame, the parameters of which are correlated with grid voltage asymmetry. The proposed method results in resignation from resonant terms used as controllers and their replacement with proportional–integral terms for which anti-wind-up structures are significantly simpler than for oscillatory terms. The paper presents new transformation principles, features and some simulation results showing the waveforms of signals transformed to the new non-Cartesian frame.

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Hernández-Gómez, Ángel, Victor Ramirez, Damien Guilbert und Belem Saldivar. „Self-Discharge of a Proton Exchange Membrane Electrolyzer: Investigation for Modeling Purposes“. Membranes 11, Nr. 6 (22.05.2021): 379. http://dx.doi.org/10.3390/membranes11060379.

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The self-discharge phenomenon results in a decrease of the open-circuit voltage (OCV), which occurs when an electrochemical device is disconnected from the power source. Although the self-discharge phenomenon has widely been investigated for energy storage devices such as batteries and supercapacitors, no previous works have been reported in the literature about this phenomenon for electrolyzers. For this reason, this work is mainly focused on investigating the self-discharge voltage that occurs in a proton exchange membrane (PEM) electrolyzer. To investigate this voltage drop for modeling purposes, experiments have been performed on a commercial PEM electrolyzer to analyze the decrease in the OCV. One model was developed based on different tests carried out on a commercial-400 W PEM electrolyzer for the self-discharge voltage. The proposed model has been compared with the experimental data to assess its effectiveness in modeling the self-discharge phenomenon. Thus, by taking into account this voltage drop in the modeling, simulations with a higher degree of reliability were obtained when predicting the behavior of PEM electrolyzers.

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Makasheva, Svetlana, Pavel Pinchukov, Aleksandr Mamaev und Sergey Terleckiy. „ESTIMATE OF VOLTAGE QUALITY ON TRACTION SUBSTATION BUSES OF 27.5 kV WITH LONGITUDINAL CAPACITIVE COMPENSATION DEVICE“. Bulletin of Bryansk state technical university 2020, Nr. 3 (05.03.2020): 11–20. http://dx.doi.org/10.30987/1999-8775-2020-3-11-20.

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The paper is dedicated to the investigation of electric energy quality in AC traction network. The object of investigations is voltage in the AC traction network on buses of 27.5 kV in the AC functioning substation. The probabilistic-statistical value of the voltage level and values of electric energy quality according to voltage non-sinusoidality is under fulfillment. There are shown numerical characteristics and histograms of the distribution density of values under analysis for two operation modes of the AC traction substation – switching on and off of the longitudinal capacitive compensation device formed on the basis of natural measurements. The probabilistic-statistical processing of natural measurements results in power supply arms of the functioning traction substation located in the Far-East of the Russian Federation is carried out. The analysis results are shown as distribution density histograms of random values according to the standard law and in a table form. The longitudinal compensation device impact upon quality values of electric power according to the voltage is under consideration. The calculated indices of electric power quality at the traction substation are compared with the requirements of GOST 32144-2013 in force. It is mentioned that upon buses of 27.5 kV of the traction substation both in the mode of UPK switching on, and in the mode of its switching off the electric power quality by the factor of voltage harmonic components does not satisfy the requirements of GOST 32144-2013 in a number of harmonics. On the basis of the complex estimate of voltage parameters there is drawn a conclusion of the positive impact of longitudinal capacitive compensation devices upon voltage level and the absence of a distinct effect upon a harmonic structure of voltage in a traction network at longitudinal compensation switching on. The conclusion is drawn about filtration expediency of voltage highest harmonic components in power supply arms of the traction substation to bring quality indices on voltage non-sinusoidality to the requirements of the standard in force.

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Bayar, Secil, Ahmet Karagunduz und Bulent Keskinler. „Influences of electroosmosis and electrophoresis on permeate flux and membrane fouling in submerged membrane bioreactors (SMBRs)“. Water Science and Technology 74, Nr. 3 (08.06.2016): 766–76. http://dx.doi.org/10.2166/wst.2016.280.

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The objective of this study was to investigate the influences of electroosmosis (EO) and electrophoresis (EP) on the permeate flux in submerged membrane bioreactors. When a polymeric membrane is placed in between an anode and a cathode, both EO and EP occur simultaneously, causing enhancement in flux. Results showed that after 150 min of filtration, the permeate fluxes were 60, 115, 175 and 260 L/m2/h at 0, 30, 40 and 50 V, respectively. It was shown that the EO was linearly changing with increasing voltage, reaching up to 54 L/m2/h at 50 V. EP was found to be a significant process in removing soluble microbial products from the membrane surface, resulting in an increase in permeate flux as the filtration progressed. About 20-fold of smaller protein and carbohydrate concentrations were found in the cake layer when the electrical field (EF) was applied. However, the EF application promoted pore fouling, because of the calcium and magnesium scaling.

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Opoku-Duah, Stephen, und Dennis Johnson. „Removal of Perfluorooctanoic Acid and Microcystins from Drinking Water by Electrocoagulation“. Journal of Chemistry 2020 (19.08.2020): 1–10. http://dx.doi.org/10.1155/2020/1836264.

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Perfluorooctanoic acid (PFOA) and microcystins are some of the well-known chemical contaminants in drinking water in the USA. Despite the availability of filtration technologies like ion-exchange resins, activated-carbon, and high-pressure membrane filters, these contaminants still remain widespread in the environment. In the present study, two innovative aspects of electrocoagulation techniques were tested, (a) cheap and easy-to-operate field-unit instead of hi-tech electrocoagulation and (b) reverse-polarity instead of conventional polarity, and applied to remove PFOA and microcystins from drinking water sources. The method presented here outperformed commercial activated-carbon filtration by nearly 40%. When the efficiency of electrocoagulation was examined in terms of voltage discharge, pH, and reverse-polarity, the results averaged 80% decontamination for individual treatment, while their combined effects produced 100% detoxification in 10–40 minutes, exceeding recently published results. The method shows great economic promise for water and wastewater treatment and chemical recycling.

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Kwon, Joon Yub, Seo Bong Chang, Yong Oh Jang, Mohamed Dawod und Doo Soo Chung. „Highly sensitive analysis of catecholamines by counter-flow electrokinetic supercharging in the constant voltage mode“. Journal of Separation Science 36, Nr. 12 (20.05.2013): 1973–79. http://dx.doi.org/10.1002/jssc.201201154.

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