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.

scholarly journals The Three-Dimensional Locating of VHF Broadband Lightning Interferometers

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 317 ◽  
Author(s):  
Hengyi Liu ◽  
Shi Qiu ◽  
Wansheng Dong
Keyword(s):  
Time Resolution ◽  
High Frequency ◽  
Three Dimensional ◽  
High Time Resolution ◽  
Very High Frequency ◽  
Time Difference Of Arrival ◽  
Lightning Discharges ◽  
Total Lightning ◽  
Locating Information ◽  
Very High

VHF (Very High Frequency) lightning interferometers can locate and observe lightning discharges with a high time resolution. Especially the appearance of continuous interferometers makes the 2-D location of interferometers further improve in time resolution and completeness. However, there is uncertainty in the conclusion obtained by simply analyzing the 2-D locating information. Without the support of other 3-D total lightning locating networks, the 2-station interferometer becomes an option to obtain 3-D information. This paper introduces a 3-D lightning location method of a 2-station broadband interferometer, which uses the theodolite wind measurement method for reference, and gives the simulation results of the location accuracy. Finally, using the multi-baseline continuous 2-D locating method and the 3-D locating method, the locating results of one intra-cloud flash and the statistical results of the initiation heights of 61 cloud-to-ground flashes and 80 intra-cloud flashes are given. The results show that the two-station interferometer has high observation accuracy on both sides of the connection between the two sites. The locating accuracy will deteriorate as the distance between the radiation source and the two stations increases or the height decreases. The actual locating results are similar to those of the existing VHF TDOA (Time Difference of Arrival) lightning locating network.

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.

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.

Very High Frequency Radio Emissions Associated With the Production of Terrestrial Gamma-Ray Flashes

2018 ◽  
Vol 45 (4) ◽  
pp. 2097-2105 ◽  
Author(s):  
Fanchao Lyu ◽  
Steven A. Cummer ◽  
Paul R. Krehbiel ◽  
William Rison ◽  
Michael S. Briggs ◽  
...  
Keyword(s):  
High Frequency ◽  
Gamma Ray ◽  
Very High Frequency ◽  
Radio Emissions ◽  
Very High

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’.

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 Observations of multi-microsecond VHF pulsetrains in energetic intracloud lightning discharges

2011 ◽  
Vol 29 (9) ◽  
pp. 1587-1604 ◽  
Author(s):  
A. R. Jacobson ◽  
R. H. Holzworth ◽  
X.-M. Shao
Keyword(s):  
Radio Emission ◽  
Amplitude Distribution ◽  
The Other ◽  
Radio Noise ◽  
Statistical Measures ◽  
Lower Hemisphere ◽  
Propagation Effects ◽  
Lightning Discharges ◽  
Intracloud Discharges ◽  
Intense Radio

Abstract. Certain intracloud lightning discharges emit energetic, multi-microsecond pulsetrains of radio noise. Observations of this distinctive form of lightning date from 1980 and have involved both ground-based and satellite-based radio recording systems. The underlying intracloud lightning discharges have been referred to as "Narrow Bipolar Pulses", "Narrow Bipolar Events", and "Compact Intracloud Discharges". An important discriminant for this species of radio emission is that, in the range above ~30 MHz, it consists of several microseconds of intense radio noise. When the intracloud emission is viewed from a satellite, each radio pulsetrain is received both from a direct lightning-to-satellite path, and after some delay, from a path via ground. Thus one recording of the radio emission, if of sufficient length, contains the "view" of the intracloud emission from two different angles. One view is of radiation exiting the emitter into the upper hemisphere, the other for radiation exiting into the lower hemisphere. However, the propagation conditions are similar, except that one path includes a ground reflection, while the other does not. One would normally expect a stereoscopic double view of the "same" emission process to provide two almost congruent time series, one delayed from the other, and also differing due to the different propagation effects along the two signal paths, namely, the ground reflection. We present somewhat unexpected results on this matter, using recordings from the FORTE satellite at a passband 118–141 MHz, with simultaneous data at 26–49 MHz. We find that the 118–141 MHz pulsetrain's detailed time-dependence is completely uncorrelated between the two views of the process. We examine statistics of the 118–141 MHz pulsetrain's integrated power and show that the power emitted into the lower hemisphere, on average, exceeds the power emitted into the upper hemisphere. Finally, we examine statistical measures of the amplitude distribution and show that the 118–141 MHz signal emitted downward is slightly more dominated by discrete, temporally-narrow impulses than is the signal emitted upward.

Comparison of Narrow Bipolar Events with Ordinary Lightning as Proxies for Severe Convection

2005 ◽  
Vol 133 (5) ◽  
pp. 1144-1154 ◽  
Author(s):  
Abram R. Jacobson ◽  
Mathew J. Heavner
Keyword(s):  
Remote Sensing ◽  
Low Frequency ◽  
Cosmic Ray ◽  
Detailed Comparison ◽  
Discharge Process ◽  
Very High Frequency ◽  
Radio Emissions ◽  
Severe Convection ◽  
Relationship Of ◽  
The Relationship

Abstract Narrow bipolar events (NBEs) are a recently studied intracloud electrical-discharge process. It is speculated that an NBE is instigated by the extensive atmospheric shower of an energetic cosmic ray. NBEs cause significant relaxation of the charge separation within the electrified cloud in a short time, on the order of 10 μs. The current flow causes radiation of a distinctive “bipolar” low-frequency/very low frequency signal that can be recorded at locations on earth up to thousands of kilometers from the source. NBEs are preceded/accompanied by the most powerful very high frequency radio emissions seen in any kind of lightning. These intense pulsed radio emissions have been routinely detected with satellite-borne radio receivers in space. Owing to their easy detection and recognition, NBEs might be a useful remote sensing proxy for space-based global, near–real time remote sensing. However, in order for that potential to be realized, NBEs must be shown to be associated, as is ordinary lightning, with severe tropospheric convection, rather than to be just a curiosity of cosmic-ray–atmosphere interactions. This question is addressed with a detailed comparison of NBEs and ordinary lightning using a ground-based lightning-transient research facility that records signals from both ordinary lightning and NBEs, the Los Alamos Sferic-waveform Array (LASA), based in Florida. First, the data from LASA are internally compared to examine the relationship of NBEs and ordinary lightning in both position and time. Second, the relationship of both NBEs and ordinary lightning to simultaneous infrared cloud imagery is examined [from the Geostationary Operational Environmental Satellite-East (GOES-East)] in order to infer the relative affinities of NBEs and ordinary lightning for cloud signatures that are consistent with severe convection.

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