Search results for "DEFECTS"
showing 10 items of 339 documents
Visual defects in subjects with Down’s syndrome
1995
Because the incidence of other visual defects is much higher in cases of Down’s syndrome than in individuals with other forms of retardation (Gardiner, 1967; Aitchison et al., 1990), we tested the color vision of a population of Down’s syndrome patients, using Ishihara plates and the Davico anomaloscope. The Down’s syndrome group had a significantly higher proportion of color deficiencies than either normal controls or a matched mentally retarded population. Refractive errors were corrected with static retinoscopy, and spatial contrast sensitivity was measured with the Vistech test.
Deep traps in InGaN/GaN single quantum well structures grown with and without InGaN underlayers
2020
The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the high temperature GaN buffer and the QW region. Capacitance-voltage profiling with monochromatic illumination showed that in the InGaN underlayer (UL), the density of deep traps with optical threshold near 1.5 eV was much higher than in the QW and higher than for structures without InGaN. Irradiation with 5 MeV electrons strongly increased the concentration of these 1.5 eV traps in the QWs, with the increase more pronounced for samples witho…
SIRM–SIC appropriateness criteria for the use of Cardiac Computed Tomography. Part 1: Congenital heart diseases, primary prevention, risk assessment …
2021
AbstractIn the past 20 years, Cardiac Computed Tomography (CCT) has become a pivotal technique for the noninvasive diagnostic work-up of coronary and cardiac diseases. Continuous technical and methodological improvements, combined with fast growing scientific evidence, have progressively expanded the clinical role of CCT. Recent large multicenter randomized clinical trials documented the high prognostic value of CCT and its capability to increase the cost-effectiveness of the management of patients with suspected CAD. In the meantime, CCT, initially perceived as a simple non-invasive technique for studying coronary anatomy, has transformed into a multiparametric “one-stop-shop” approach abl…
A Comparison between the Latest Models of Li-Ion Batteries and Petrol Chainsaws Assessing Noise and Vibration Exposure in Cross-Cutting
2023
Chainsaw operators are exposed to many hazards that can lead to health problems. The two most frequently documented ergonomics threats in the use of chainsaws are noise and vibration exposure. Since the use of battery chainsaws is increasing due to the growing improvements in battery life and power, the study aims to compare the difference in terms of noise emission and vibration levels of the following two new models of chainsaws: the battery-powered Stihl MSA 300 and the petrol-powered Stihl MS 261 C-M. Black pine and European beech logs were cross-cut in order to evaluate both noise and vibration exposure. The results show that the use of battery-powered chainsaws, in comparison to the p…
Wpływ składu chemicznego i mikrostruktury na odporność stali na niszczenie wodorowe
2014
W pracy przedstawiono podsumowanie dotychczasowych wyników badań i poglądów dotyczących czynników wywierających wpływ na odporność stali na niszczenie wodorowe. O degradacji stali eksploatowanych w warunkach oddziaływania wodoru w głównej mierze decyduje ich stan, a w szczególności mikrostruktura,technologia wytwarzania oraz defekty występujące w ich strukturze.
PCB-Based Planar Inductive Loops for Partial Discharges Detection in Power Cables
2022
Partial discharge (PD) diagnosis tests, including detecting, locating, and identifying, are used to trace defects or faults and assess the degree of aging in order to monitor the insulation condition of medium- and high-voltage power cables. In this context, an experimental evaluation of three different printed circuit board (PCB)-based inductive sensor topologies, with spiral, non-spiral, and meander shapes, is performed. The aim is to assess their capabilities for PD detection along a transmission power cable. First, simulation and experimental characterization are carried out to determine the equivalent electrical circuit and the quality factor of the three sensors. PD activity was studi…
Influence of Ge doping level on the EPR signal of Ge(1), Ge(2) and E'Ge defects in Ge-doped silica
2011
Abstract We present an experimental investigation on the Ge doping level dependence of the Electron Paramagnetic Resonance (EPR) signal spectral features of the Ge(1), Ge(2) and E'Ge defects induced in Ge doped silica. We have studied samples produced by sol–gel or PCVD techniques and doped with different amounts of Ge up to 20% by weight. The samples were gamma or beta ray irradiated and successively they were thermally treated to isolate the EPR signals of the different point defects. The data show that the EPR line shapes of the Ge(1) and the Ge(2) centers are progressively modified for doping level higher than 1%, whereas the line shape of the E'Ge defect appears independent from the do…
Dependence of the emission properties of the germanium lone pair center on Ge doping of silica
2011
We present an experimental investigation regarding the changes induced by the Ge doping level on the emission profile of the germanium lone pair center (GLPC) in Ge doped silica. The investigated samples have been produced by the sol-gel method and by plasma-activated chemical vapor deposition and have doping levels up to 20% by weight. The recorded photoluminescence spectra show that the GLPC emission profile is the same when the Ge content is lower than ∼ 1% by weight, whereas it changes for higher doping levels. We have also performed Raman scattering measurements that show the decrease of the D1 Raman band at 490 cm( - 1) when the Ge content is higher than 1% by weight. The data suggest…
CLINICAL STUDY OF TRANSVERSAL AUGMENTATION IN BONE DEFECTS OF THE MAXILLARY AESTETHIC AREA
2015
Scope: To outline the importance of autogenic bone graft addition for correcting bone defects in the frontal and lateral maxillary area, and for achieving outstanding esthetic results in cases of large bone defects. Materials and method: A total number of 478 argumentations has been performed in the implantology and dental clinic of the Emergency Military Hospital Sibiu between 2009 and 2013. Results and discussion: The transversal rehabilitation techniques of frontal maxillary ridges, representing 57.2% of all addressed cases, were the most frequent ones, justifying the fact that the frontal maxillary area, aesthetically sensitive, is of special attention for both patients and specialists.…
FMEA - BASIC CONCEPT IN PRODUCT QUALITY
2018
Failure modes and effects analysis (FMEA) is a systematic procedure for analyzing a system (the entire system or just an assembly, subassembly or component) to identify potential failure modes, causes and effects of each failure on system operation. A somewhat different definition was formulated by Goddard Space Flight Center (USA) : FMEA is a procedure whereby every credible way of defeating each item from the lower decomposition level to the highest level is analyzed to determine effects on the system and classify each potential way of failure according to the severity of its effect.