scholarly journals Fouling Reduction Via Air Backpulsing in Dairy Wastewater Microfiltration

2021 ◽  
Author(s):  
Mahsa Ashtari
Keyword(s):  
Membrane Fouling ◽  
High Pressures ◽  
Skim Milk ◽  
Dairy Wastewater ◽  
Very High Frequency ◽  
Filtration Process ◽  
Flat Sheet Membrane ◽  
The One ◽  
Very High Frequencies ◽  
Very High

Membrane fouling mitigation in dairy wastewater microfiltration was investigated through air back pulsing. Flat sheet membrane module with pore size of 0.1 mm was used. The model dairy wastewater was prepared by skim milk diluted with distilled water (milk:water = 1:2). The effect of three parameters, including air back pulsing pressure (pb), back pulsing frequency (f), and back pulsing duration (d) on fouling control was investigated. It was found that high pressures of air in short durations of back pulsing can improve the filtration process and result in higher amounts of permeate. However, it is anticipated that beyond the region of study, very high frequency would not be helpful. Very high frequencies mean short back pulsing durations, and this might result in loss of positive effect of back pulsing. The maximum permeate amount obtained using back pulsing assisted filtration process was 83% higher than the one obtained without back pulsing.

scholarly journals Fouling Reduction Via Air Backpulsing in Dairy Wastewater Microfiltration

2021 ◽  
Author(s):  
Mahsa Ashtari
Keyword(s):  
Membrane Fouling ◽  
High Pressures ◽  
Skim Milk ◽  
Dairy Wastewater ◽  
Very High Frequency ◽  
Filtration Process ◽  
Flat Sheet Membrane ◽  
The One ◽  
Very High Frequencies ◽  
Very High

Membrane fouling mitigation in dairy wastewater microfiltration was investigated through air back pulsing. Flat sheet membrane module with pore size of 0.1 mm was used. The model dairy wastewater was prepared by skim milk diluted with distilled water (milk:water = 1:2). The effect of three parameters, including air back pulsing pressure (pb), back pulsing frequency (f), and back pulsing duration (d) on fouling control was investigated. It was found that high pressures of air in short durations of back pulsing can improve the filtration process and result in higher amounts of permeate. However, it is anticipated that beyond the region of study, very high frequency would not be helpful. Very high frequencies mean short back pulsing durations, and this might result in loss of positive effect of back pulsing. The maximum permeate amount obtained using back pulsing assisted filtration process was 83% higher than the one obtained without back pulsing.

scholarly journals Parametric Fault Diagnosis of Very High-Frequency Circuits Containing Distributed Parameter Transmission Lines

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 550
Author(s):  
Michał Tadeusiewicz ◽  
Stanisław Hałgas
Keyword(s):  
Fault Diagnosis ◽  
Transmission Lines ◽  
High Frequency ◽  
Diagnostic Method ◽  
Distributed Parameter ◽  
Very High Frequency ◽  
Parametric Fault ◽  
The One ◽  
Very High ◽  
Parameter Transmission

Parametric fault diagnosis of analog very high-frequency circuits consisting of a distributed parameter transmission line (DPTL) terminated at both ends by lumped one-ports is considered in this paper. The one-ports may include linear passive and active components. The DPTL is a uniform two-conductor line immersed in a homogenous medium, specified by the per-unit-length (p-u-l) parameters. The proposed method encompasses all aspects of parametric fault diagnosis: detection of the faulty area, location of the fault inside this area, and estimation of its value. It is assumed that only one fault can occur in the circuit. The diagnostic method is based on a measurement test arranged in the AC state. Different approaches are proposed depending on whether the faulty is DPTL or one of the one-ports. An iterative method is modified to solve various systems of nonlinear equations that arise in the course of the diagnostic process. The diagnostic method can be extended to a broader class of circuits containing several transmission lines. Three numerical examples reveal that the proposed diagnostic method is fast and gives quite accurate findings.

A-Si:H Solar Cells Deposited Using VHF–PECVD

1996 ◽  
Vol 420 ◽  
Author(s):  
W. G. J. H. M. Van Sark ◽  
J. Bezemer ◽  
R. Van Der Heijden ◽  
W. F. Van Der Weg
Keyword(s):  
Solar Cells ◽  
Chemical Vapour ◽  
Clear Correlation ◽  
Rf Power ◽  
Material Quality ◽  
High Frequencies ◽  
Cell Parameters ◽  
The One ◽  
Very High Frequencies ◽  
Very High

AbstractA-Si:H p+-i-n+ solar cells have been made employing plasma enhanced chemical vapour deposition at frequencies between 30–80 MHz. Here, only the i-layer was fabricated at these very high frequencies (VHF). Both the p+- and n+-layer were made using 13.56 MHz. A previous study has shown the material quality to depend on mainly the applied rf-power, and only slightly on the frequency. It should be noted that for homogeneity reasons a certain optimized pressure is required for each frequency. There is a clear correlation between material quality and solar cell parameters. An initial efficiency of 10 % has been obtained for cells deposited at 65 MHz using a low power density, while the deposition rate still is 2–3 times higher than the one at 13.56 MHz. Light-soaking reveals stabilisation at 6 % for the best cell, which compares well to conventional 13.56 MHz cells.

scholarly journals Gd3+–Gd3+ distances exceeding 3 nm determined by very high frequency continuous wave electron paramagnetic resonance

2017 ◽  
Vol 19 (7) ◽  
pp. 5127-5136 ◽  
Author(s):  
Jessica A. Clayton ◽  
Mian Qi ◽  
Adelheid Godt ◽  
Daniella Goldfarb ◽  
Songi Han ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Very High Frequency ◽  
Fundamental Study ◽  
Paramagnetic Resonance ◽  
High Frequencies ◽  
Biologically Relevant ◽  
Lineshape Analysis ◽  
Very High Frequencies ◽  
Electron Paramagnetic ◽  
Very High

We present a fundamental study of a CW EPR lineshape analysis-based approach to determining Gd–Gd distances at very high frequencies (240 GHz). The approach is demonstrated from cryogenic to biologically-relevant temperatures.

scholarly journals Are Humans Constantly but Subconsciously Smelling Themselves?

2020 ◽  
Author(s):  
Ofer Perl ◽  
Eva Mishor ◽  
Aharon Ravia ◽  
Inbal Ravreby ◽  
Noam Sobel
Keyword(s):  
High Frequency ◽  
Self Report ◽  
Very High Frequency ◽  
Psychological Literature ◽  
Nasal Inhalation ◽  
The One ◽  
Very High ◽  
Functional Purpose

All primates, including humans, engage in self-face-touching at very high frequency. The functional purpose or antecedents of this behaviour remain unclear. In this hybrid review we put forth the hypothesis that self-face-touching subserves self-smelling. We first review data implying that humans touch their own face at very high frequency. We then detail evidence from the one study that implicated an olfactory origin for this behaviour: This evidence consists of significantly increased nasal inhalation concurrent with self-face-touching, and predictable increases or decreases in self-face-touching as a function of subliminal odourant tainting. Although we speculate that self-smelling through self-face-touching is largely an unconscious act, we note that in addition, humans also consciously smell themselves at high frequency. To verify this added statement, we administered an online self-report questionnaire. Upon being asked, ~94% of ~400 respondents acknowledged engaging in smelling themselves. Paradoxically, we observe that although this very prevalent behaviour of self-smelling is of concern to individuals, especially to parents of children overtly exhibiting self-smelling, the behaviour has nearly no traction in the medical or psychological literature. We suggest psychological and cultural explanations for this paradox, and end in suggesting that human self-smelling become a formal topic of investigation in the study of human social olfaction.

scholarly journals Resistance of the Montgomery Ladder Against Simple SCA: Theory and Practice

2021 ◽  
Author(s):  
Ievgen Kabin ◽  
Zoya Dyka ◽  
Dan Klann ◽  
Marcin Aftowicz ◽  
Peter Langendoerfer
Keyword(s):  
Elliptic Curve ◽  
Power Analysis ◽  
Theory And Practice ◽  
High Frequencies ◽  
Montgomery Ladder ◽  
Wide Range ◽  
The One ◽  
Very High Frequencies ◽  
Vhdl Code ◽  
Very High

AbstractThe Montgomery kP algorithm i.e. the Montgomery ladder is reported in literature as resistant against simple SCA due to the fact that the processing of each key bit value of the scalar k is done using the same sequence of operations. We implemented the Montgomery kP algorithm using Lopez-Dahab projective coordinates for the NIST elliptic curve B-233. We instantiated the same VHDL code for a wide range of clock frequencies for the same target FPGA and using the same compiler options. We measured electromagnetic traces of the kP executions using the same input data, i.e. scalar k and elliptic curve point P, and measurement setup. Additionally, we synthesized the same VHDL code for two IHP CMOS technologies, for a broad spectrum of frequencies. We simulated the power consumption of each synthesized design during an execution of the kP operation, always using the same scalar k and elliptic curve point P as inputs. Our experiments clearly show that the success of simple electromagnetic analysis attacks against FPGA implementations as well as the one of simple power analysis attacks against synthesized ASIC designs depends on the target frequency for which the design was implemented and at which it is executed significantly. In our experiments the scalar k was successfully revealed via simple visual inspection of the electromagnetic traces of the FPGA for frequencies from 40 to 100 MHz when standard compile options were used as well as from 50 MHz up to 240 MHz when performance optimizing compile options were used. We obtained similar results attacking the power traces simulated for the ASIC. Despite the significant differences of the here investigated technologies the designs’ resistance against the attacks performed is similar: only a few points in the traces represent strong leakage sources allowing to reveal the key at very low and very high frequencies. For the “middle” frequencies the number of points which allow to successfully reveal the key increases when increasing the frequency.

scholarly journals Are humans constantly but subconsciously smelling themselves?

2020 ◽  
Vol 375 (1800) ◽  
pp. 20190372 ◽  
Author(s):  
Ofer Perl ◽  
Eva Mishor ◽  
Aharon Ravia ◽  
Inbal Ravreby ◽  
Noam Sobel
Keyword(s):  
High Frequency ◽  
Self Report ◽  
Olfactory Communication ◽  
Very High Frequency ◽  
Psychological Literature ◽  
Nasal Inhalation ◽  
The One ◽  
Very High ◽  
Functional Purpose

All primates, including humans, engage in self-face-touching at very high frequency. The functional purpose or antecedents of this behaviour remain unclear. In this hybrid review , we put forth the hypothesis that self-face-touching subserves self-smelling. We first review data implying that humans touch their faces at very high frequency. We then detail evidence from the one study that implicated an olfactory origin for this behaviour: This evidence consists of significantly increased nasal inhalation concurrent with self-face-touching, and predictable increases or decreases in self-face-touching as a function of subliminal odourant tainting. Although we speculate that self-smelling through self-face-touching is largely an unconscious act, we note that in addition, humans also consciously smell themselves at high frequency. To verify this added statement, we administered an online self-report questionnaire. Upon being asked, approximately 94% of approximately 400 respondents acknowledged engaging in smelling themselves. Paradoxically, we observe that although this very prevalent behaviour of self-smelling is of concern to individuals, especially to parents of children overtly exhibiting self-smelling, the behaviour has nearly no traction in the medical or psychological literature. We suggest psychological and cultural explanations for this paradox, and end in suggesting that human self-smelling become a formal topic of investigation in the study of human social olfaction. This article is part of the Theo Murphy meeting issue ‘Olfactory communication in humans’.

Studies on Fouling and its Prevention in MBRs

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
B. Siembida ◽  
P. Cornel ◽  
S. Krause ◽  
B. Zimmermann
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Bioreactors ◽  
High Flux ◽  
Chemical Cleaning ◽  
Sustainable Operation ◽  
The One ◽  
The Impact ◽  
Very High ◽  
Mechanical Cleaning

Investigations of fouling alleviation and permeability decline in membrane bioreactors (MBR) were carried out at two pilot plants. On the one hand, the minimization of membrane fouling via adding abrasive granulates into activated sludge (submerged operated membrane) was tested. On the other hand, the impact of truly soluble compounds released into the liquid phase of activated sludge on fouling behavior was investigated. The first research into the impact of mechanical cleaning via adding granulates showed the unwanted formation of fouling layers was reduced as a result of abrasion processes. With this method continuous sustainable operation was achieved, without chemical cleaning and, at the same time, reaching very high flux levels up to 40 L/(m2·h) over more than 500 days (>16 months). The investigation of the effect of truly soluble compounds on membrane fouling showed that the permeability decline during 145 days of operation resulted predominantly from wastewater or activated sludge matter larger than 0.04 μm.

scholarly journals Joint radio and optical observations of the most radio-powerful intracloud lightning discharges

2013 ◽  
Vol 31 (3) ◽  
pp. 563-580 ◽  
Author(s):  
A. R. Jacobson ◽  
T. E. L. Light ◽  
T. Hamlin ◽  
R. Nemzek
Keyword(s):  
Optical Observations ◽  
Discharge Process ◽  
Very High Frequency ◽  
Radio Emissions ◽  
Lightning Discharges ◽  
Usual Behavior ◽  
The One ◽  
Intracloud Discharges ◽  
Intense Radio ◽  
Very High

Abstract. The most radio-powerful intracloud lightning emissions are associated with a phenomenon variously called "narrow bipolar events" or "compact intracloud discharges". This article examines in detail the coincidence and timing relationship between, on the one hand, the most radio-powerful intracloud lightning events and, on the other hand, optical outputs (or lack thereof) of the same discharge process. This is done, first, using coordinated very high frequency (VHF) and optical observations from the FORTE satellite and, second, using coordinated sferic and all-sky optical observations from the Los Alamos Sferic Array. In both cases, it is found that the sought coincidences are exceedingly rare. Moreover, in the handful of coincidences between optical and intense radio emissions that have been identified, the radio emissions differ from their usual behavior, by being accompanied by approximately simultaneous "conventional" lightning radio emissions. It is implied that the most radio-powerful intracloud emission process essentially differs from ordinary incandescent lightning.

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