Search results for "Measurements"

New Theoretical Solution of Stage-Discharge Relationship for Slit Weirs

2018

In this paper, the flow-process of a slit weir was analyzed on the basis of a theorem of dimensional analysis and incomplete selfsimilarity theory. The theoretically deduced stage-discharge formula then was calibrated using experimental data obtained for a ratio between the weir and the channel width, ranging from 0.05 to 0.25. The deduced stage-discharge relationship allowed measuring discharge values characterized by errors that, for 98% of the measured values, were less than or equal to 5%. The performance of the proposed theoreticalstage-discharge formula also was improved by introducing the Reynolds number (for 98.5% of the measured values the error was less than or equal to 5%, and th…

Time Evolution of Partial Discharges in a Dielectric Subjected to the DC Periodic Voltage

2022

Partial discharge (PD) detection can be considered one of the most useful tools for assessing the insulation conditions of the power apparatus in high-voltage systems. Under AC conditions, this analysis is widely employed in online and offline tests, such as type tests or commissioning, and can be carried out by applying the phase-resolved PD (PRPD) method, since the patterns can give information about the defect classification. Under DC voltages, the classic pattern recognition method cannot be performed, and the measurements show complexities related to the nature of the phenomena. For this reason, to date, a standard for PD measurements under DC does not exist. In previous papers, a new …

Intraoperative microvascular Doppler monitoring of blood flow within a spinal dural arteriovenous fistula: a precious surgical tool. Case report.

2001

The authors describe a case of spinal arteriovenous fistula (AVF) treated by a microvauscular Doppler–assisted surgical interruption of the arterialized vein. Microvascular Doppler monitoring represents a valid, widely available, non-invasive tool that enables identification, through flow spectrum analysis, of components of this type of vascular malformation. In this case because the location of the fistula was identified prior to opening the dura only minimally invasive surgery was required. Direct recordings of the arterialized draining vein and the nidus of the fistula demonstrated a pathological spectrum caused by the arterial supply and the disturbed venous outflow in which a high-resi…

Trace gas composition in the Asian summer monsoon anticyclone: a case study based on aircraft observations and model simulations

2017

We present in situ measurements of the trace gas composition of the upper tropospheric (UT) Asian summer monsoon anticyclone (ASMA) performed with the High Altitude and Long Range Research Aircraft (HALO) in the frame of the Earth System Model Validation (ESMVal) campaign. Air masses with enhanced O3 mixing ratios were encountered after entering the ASMA at its southern edge at about 150 hPa on 18 September 2012. This is in contrast to the presumption that the anticyclone's interior is dominated by recently uplifted air with low O3 in the monsoon season. We also observed enhanced CO and HCl in the ASMA, which are tracers for boundary layer pollution and tropopause layer (TL) air or stratosp…

Toxicity assessment of pesticides using the microtox test: application to environmental samples.

1997

A Novel Technique for Deembeding the Unloaded Resonance Frequency from Measurements of Microwave Cavities

2006

[EN] A novel technique to extract the influence of coupling networks on the resonant frequency of cavities in one-port measurements is presented. The determination of the unloaded resonant frequency is performed directly from measurements without either the need to obtain the electromagnetic fields in the resonator or to deembed the delay of transmission lines from the measuring equipment to the resonator. The importance of the Foster's form on the modeling of the frequency detuning of the resonators is also discussed and a criterion for the choice of the appropriate Foster's form is suggested. The procedure is validated with simulations and experimental measurements of manufactured cavities

Photosensitivity of SiO2–Al and SiO2–Na glasses under ArF (193 nm) laser

2009

Abstract Photosensitivity of SiO 2 –Al and SiO 2 –Na glass samples was probed by means of the induced optical absorption and luminescence as well as by electron spin-resonance (ESR) after irradiation with excimer-laser photons (ArF, 193 nm). Permanent visible darkening in the case of SiO 2 –Al and transient, life time about one hour, visible darkening in the case of SiO 2 –Na was found under irradiation at 290 K. No darkening was observed at 80 K for either kind of material. This investigation is dedicated to revealing the electronic processes responsible for photosensitivity at 290 and 80 K. The photosensitivity of both materials is related to impurity defects excited directly in the case …

Ultra-fast direct growth of metallic micro- and nano-structures by focused ion beam irradiation

2019

An ultra-fast method to directly grow metallic micro- and nano-structures is introduced. It relies on a Focused Ion Beam (FIB) and a condensed layer of suitable precursor material formed on the substrate under cryogenic conditions. The technique implies cooling the substrate below the condensation temperature of the gaseous precursor material, subsequently irradiating with ions according to the wanted pattern, and posteriorly heating the substrate above the condensation temperature. Here, using W(CO)6 as the precursor material, a Ga+ FIB, and a substrate temperature of -100 °C, W-C metallic layers and nanowires with resolution down to 38 nm have been grown by Cryogenic Focused Ion Beam Indu…

Dielectrophoretic trapping of multilayer DNA origami nanostructures and DNA origami-induced local destruction of silicon dioxide

2015

DNA origami is a widely used method for fabrication of custom-shaped nanostructures. However, to utilize such structures, one needs to controllably position them on nanoscale. Here we demonstrate how different types of 3D scaffolded multilayer origamis can be accurately anchored to lithographically fabricated nanoelectrodes on a silicon dioxide substrate by DEP. Straight brick-like origami structures, constructed both in square (SQL) and honeycomb lattices, as well as curved "C"-shaped and angular "L"-shaped origamis were trapped with nanoscale precision and single-structure accuracy. We show that the positioning and immobilization of all these structures can be realized with or without thi…

Koblācija un radiofrekvences ķirurģija otolaringoloģijā. Literatūras apskats un salīdzinoši eksperimenti in vitro

2016

Radiofrekvences un radiofrekvences koblācijas metodes aizvien vairāk tiek pielietotas kā rīkles, tā deguna gliemežnīcu ķirurģijā, tomēr dati par šo procedūru laikā sasniegtajām temperatūrām audos ir skopi. Eksperimentālā pētījuma pirmajā daļā in vitro tika iegūti dati par sasniegtajām temperatūrām koblācijas laikā, kā arī veikta paraugu, ņemtu instrumenta pieskaršanās zonā, histoloģiskā analīze. Cūkas muskuļaudos tika sasniegta 370°C, kamēr submandibulārā dziedzera audos – 320°C temperatūra. Eksperimentālā pētījuma otrajā daļā cūkas deguna gliemežnīcās koblācija tika salīdzināta ar divām citām bipolārām radiofrekvences metodēm, tika iegūti dati par sasniegtajām temperatūrām šo metožu pielie…