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TEC

About: TEC is a research topic. Over the lifetime, 5119 publications have been published within this topic receiving 84696 citations.


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Journal ArticleDOI
TL;DR: In this article, the authors estimate the vertical and horizontal mean speeds of the seismic and tsunami waves using the time and distance of the TEC perturbation, and then, taking into account those determined speeds, trace back to the epicenter and the tsunami origin by applying a 3-dimensional spherical model.
Abstract: The global positioning system (GPS) can be used to monitor the seismic perturbation induced by the 2011 off the Pacific coast of Tohoku Earthquake (magnitude 9.0), Japan, on March 11, 2011, and to trace the tsunami across the Pacific Ocean by measuring the changes in the ionospheric total electron content (TEC). We estimate the vertical and horizontal mean speeds of the seismic and tsunami waves using the time and distance of the TEC perturbation, and then, taking into account those determined speeds, trace back to the epicenter and the tsunami origin by applying a 3-dimensional spherical model. The results show that both the tracked epicenter and the tsunami origin are quite close to the epicenter reported by the USGS, with a mean horizontal propagation speed of 2.3 km/s after the earthquake and about 210 m/s after the tsunami. This consistency confirms that the perturbation sources in the ionosphere are due to the earthquake. This implies that the GPS-TEC measurements have the potential to be part of a lower cost, ground-based, tsunami monitoring system.

31 citations

Journal ArticleDOI
TL;DR: In this article, a gravity-assisted heat pipe (GAHP) was proposed to attach on the TEC hot side to improve the cooling performance of TEC cooling performance, and a mathematical model was established to analyze the effect of refrigerant filling ratio, temperature and air flow rate.

31 citations

Journal ArticleDOI
TL;DR: In this article, a method for obtaining the ionospheric total electron content (TEC) variations from GPS permanent station data, in a very precise manner and with high temporal and spatial resolution, is proposed.
Abstract: In this paper we propose a new and simple method for obtaining the ionospheric Total Electron Content (TEC) variations from GPS permanent station data, in a very precise manner and with high temporal and spatial resolution. The key idea is to use of the resonant period of 1 sidereal day between the Earth's rotation and the GPS satellite orbit periods, in order to obtain one TEC variation estimate directly from each ionospheric observation. This new strategy can be applied on both global and local scales, for instance to one single station. Its capabilities are shown in the application performed with the data gathered on 17, 18 and 19 October 1995 from 95 GPS permanent stations and 9 and 10 January 1997 (180 stations), coinciding with two major geomagnetic storms.

31 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of the season of the year and the sunspot number on the frequency of scintillation at a low-latitude GPS receiver and found that the scintillations mostly occur during the post-sunset to midnight hours peaking around 21:00 hr local time.
Abstract: Amplitude scintillations recorded at 1.5 GHz frequency during the high (1998–1999) and low (2004–2005) sunspot activity periods over a low latitude station, Waltair (17.7°N, 83.3°E) revealed that the L-band scintillations mostly occur during the post-sunset to midnight hours peaking around 21:00 hr local time with maximum occurrence during equinoxes, moderate during winter and minimum during the summer months. The occurrence, as well as the intensity of scintillations, is found to be strongly dependant on both the season of the year and the sunspot number. Strong (S4-index >0.45) and fast fading scintillations (fading rates >40 fads/min) observed during the post-sunset hours of equinoxes and winter months manifest as several short duration patches at both VHF (244 MHz) and L-band (1.5 GHz) frequencies and are found to be always associated with the range or total Spread-F on ionograms and bubbles/depletions in the Total Electron Content (TEC) measured from a colocated dual frequency GPS receiver, suggesting that these scintillations are of the Plasma Bubble Induced (PBI) type. On the other hand, relatively weak and slow fading scintillations (fading rates 3 hr) at 244 MHz signal (with practically no scintillation activity at the L-band frequencies) are often found to be associated with frequency Spread-F on ionograms with no depletions in TEC. Further, the presence of Fresnel oscillations observed in the spectrum of 244 MHz suggests that the long-duration scintillations observed are due to the presence of a thin layer of irregularities in the bottom side F-region which are generally known as Bottom Side Sinusoidal (BSS) irregularities. Further, the PBI-type scintillations at L-band frequencies are often found to exceed 10 dB power levels (S4 > 0.45) even during the low sunspot activity period of 2004–2005, and cause Loss of Lock in the GPS receivers resulting in a total interruption in the received signals.

31 citations

Journal ArticleDOI
TL;DR: The electrochemical degradation of tetracycline hydrochloride was comparatively investigated in artificial urine and chloride-containing media using a one-compartment filter-press flow cell composed of a Ti/Ru0.3Ti0.7O2 dimensionally stable anode and it is possible that TeC oxidation leads to intermediate compounds.
Abstract: The electrochemical degradation of tetracycline hydrochloride (TeC) was comparatively investigated in artificial urine and chloride-containing media using a one-compartment filter-press flow cell composed of a Ti/Ru0.3Ti0.7O2 dimensionally stable anode. The effect of the current density (10–40 mA cm−2) on the removal levels attained for TeC and total organic carbon (TOC) (in both media), as well as for urea and creatinine in artificial urine medium, was assessed. The TeC removal rate in the artificial urine medium was much lower than in chloride-containing medium, probably due to the higher consumption of the electrogenerated active chlorine species by the urea and creatinine in the artificial urine medium. Moreover, the obtained removal levels for the urea and creatinine were negligible at current densities lower than 30 mA cm−2. As TOC abatement was also very small, it is possible that TeC oxidation leads to intermediate compounds. Thus, if current densities less than 20 mA cm−2 are applied, TeC can be selectively removed.

31 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023303
2022578
2021284
2020321
2019293
2018272