Search results for "Discharge"
showing 10 items of 424 documents
A dense polarized 3He target based on compression of optically pumped gas
1992
Abstract 3 He-gas is spin polarized by the method of optical pumping of metastables and metastability exchange in a low pressure gas discharge. At a pressure of p ≈ 1.5 Torr a volume of 1 l is polarized within about 30 s to a degree of 50% with 300 mW of incident light from an argon-ion laser pumped LNA laser, tuned to the λ = 1.083 μm resonance line. The polarized gas is compressed by a Toepler pump into a target cell of 120 cm 3 volume. In a first attempt a steady state polarization of 30% has been achieved in the target at a pressure of 685 Torr. The paper analyses the essential parameters governing this technique and pilotes its experimental realization.
Building Partial Discharge Signal Wireless Probes
2014
This chapter focuses on the evaluation of the performances of different antenna sensors suitable for Partial Discharge (PD) measurements. Monopole, triangular and spherical antennas were simulated by means of the surface method of moments. The transmitting system is modeled by a power electronic device with a fault current between two metal plates. The shape of the simulated, transmitted and received signals, has been compared to verify the sensor that provides the best fidelity among the three. The auto-correlation function and the Pearson correlation index are adopted here for the comparison. A discussion on the dynamic characteristic of the different antenna probes and their use in diffe…
Entropic approach to estimate the mean flow velocity: experimental investigation in laboratory flumes
2015
The paper deals with the linear entropic relationship between the maximum velocity, u max , and the mean flow velocity, u m , through a dimensionless parameter Φ(M), in open-channel flow. The analysis is conducted with the aid of experimental data collected in straight laboratory flumes under different bed and side-walls roughness conditions. In particular, rough/vegetated beds and smooth/rough side-walls conditions have been investigated. The results show that, in the investigated conditions (with exception of low-submergence vegetated bed—h/k v < 2), Φ(M) can be assumed equal to a value that is very close to that found in natural channels. This demonstrates that Φ(M) is able to implicitl…
Plasma Polymer Membranes for Immobilising Metalloporphyrins
2013
Atmospheric pressure dielectric barrier discharge formation of organosilicon thin films loaded with zinc 5,10,15,20-tetraphenylporphyrin (Zn(TPP)) was investigated for different deposition conditions. UV–visible spectroscopy and scanning electron microscopy revealed the effects of the metalloporpyhrins injection parameters and the plasma polymerisation conditions can affect the dispersion of the metalloporphyrins and the morphology of the coatings. The stability of the embedded Zn(TPP) molecules was investigated by orbitrap mass spectrometry.
The effect of Transient over Voltages on the Partial Discharges activity in HVDC joints
2021
Rapid growth of HVDC cable line installations is expected in the coming years. Several research groups have investigated dielectric phenomena that occur in the insulation of HVDC cables and accessories that accelerate aging and reduce the reliability of this technology over time. Unlike in HVAC cables, under HVDC stress, the distribution of the electric field inside the insulation layer depends not only on the applied voltage but also on the temperature distribution and on other factors related to manufacturing such as the presence of impurities. Reaching local and transient electric field peaks can enhance the onset of Partial Discharges (PDs) which can lead to premature aging of the insul…
Sociodemographic factors associated with time to discharge for hospitalised patients with asthma and asthma exacerbation using the Ghana Health Servi…
2021
ObjectiveData on asthma hospitalisations are a useful source of patient morbidity information. In Ghana, the length of stay (LoS) and sociodemographic factors of patients hospitalised for asthma and its exacerbation are understudied. We aimed to investigate the time to discharge and assessed factors associated with length of hospital stays of asthmatics in Ghana.MethodsRetrospective analysis of hospitalised patient with asthma records between 2012 and 2017 from the nationwide Ghana Health Service District Health Information Management System 2 database. We calculated the cumulative incidence function for discharge stratified by age group and sex. Multivariable Cox regression was used to inv…
Survival and quality of life after early discharge in low-risk pulmonary embolism.
2020
IntroductionEarly discharge of patients with acute low-risk pulmonary embolism requires validation by prospective trials with clinical and quality-of-life outcomes.MethodsThe multinational Home Treatment of Patients with Low-Risk Pulmonary Embolism with the Oral Factor Xa Inhibitor Rivaroxaban (HoT-PE) single-arm management trial investigated early discharge followed by ambulatory treatment with rivaroxaban. The study was stopped for efficacy after the positive results of the predefined interim analysis at 50% of the planned population. The present analysis includes the entire trial population (576 patients). In addition to 3-month recurrence (primary outcome) and 1-year overall mortality, …
Investigation of Hg resonance 184.9nm line profile in a low-pressure mercury–argon discharge
2007
Abstract The line profiles of 184.9 nm Hg resonance line emitted from a Hg low-pressure high-frequency electrodeless discharge lamp, containing Hg 198 isotope, have been measured by means of a Zeeman scanning spectrometer at the mercury cold spot temperature values in the range of 0–23 °C. Two different methods were used to determine the real spectral line profile and to separate the instrument function: (i) solving the ill-posed inverse problem by means of the Tikhonov's regularization method; and (ii) the mathematical modelling by means of a non-linear multi-parameter chi-square fit. The real Hg 184.9 nm spectral line profiles, determined by both methods, are compared. Influence of instru…
A new off-line ion source facility at IGISOL
2019
An off-line ion source station has been commissioned at the IGISOL (Ion Guide Isotope Separator On-Line) facility. It offers the infrastructure needed to produce stable ion beams from three off-line ion sources in parallel with the radioactive ion beams produced from the IGISOL target chamber. This has resulted in improved feasibility for new experiments by offering reference ions for Penning-trap mass measurements, laser spectroscopy and atom trap experiments.
UV LED Photo Electron Ionisation for MS and IMS
2009
AbstractA new MEMS ionisation source for spectrometry is presented on the basis of photo electron emission in silicon MEMS. Lanthanum hexaboride ceramic sample and thin nanolayer proved their suitability for photo electron emission in the desired photon energy range of 3.1eV to 3.9eV which correspond to industrially available UV LED. This ionisation source alternative to a Photoionisationdetector (PID) is inspected of its gas ionisation behaviour using gases with an ionisation potential over and under an energy of 10,6eV. To enable the ionisation of the gases the emitted electrons were accelerated to a well-defined energy. The results of these investigations are comparable to the UV dischar…