220 research outputs found

    Non-invasive screening: The probability of events

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    Congenital anomalies are the cause of 20.0-25.0% of cases of perinatal death, while 3.0% of children are born with malformations of varying size. We examined the predictive values and defined the credibility ratio of the combined test results. Sensitivity of the test is 94.0%, and specificity is 99.0%. The positive likelihood ratio [likelihood ratio test (LR+)] is 94.00; a negative likelihood ratio [likelihood ratio test (LR-)] is 0.06. The pretest probability that pregnant women carry a fetus with chromosomal abnormality is 1:250. Posttest odds after the combined test to discover this abnormality are 0.3760, and probability of the same case is 0.2732 if it happens that the test result is positive. The result of our study confirms the justification of combined test usage in routine clinical practice, since the posttest odds rate in the case of a positive screening increases several times over (almost 90 times); the probability of detecting a chromosomal abnormality was about 70 times

    Planar photonic crystal

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    We present results of guiding light in a single-line-defect planar photonic crystal (PPC) waveguide with 90° and 60° bends. The wave guiding is obtained by total internal reflection perpendicular to the plane of propagation and by the photonic band gap for the 2D photonic crystal in the plane. The results for photonic waveguiding are shown and demonstrated at 1.5 µm wavelength

    Simulation and Measurement of Pressure Rise in GIS 145 kV due to nternal Arcing

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    Internal arc testing of metal-enclosed, SF6 gas insulated switchgear (GIS) is defined by IEC 62271-203 and is not a part of mandatory type tests. However, due to the increasing demands on the safety of personnel, more often the implementation of this test is required in the tender documentation. According to IEC, the duration of the electric arc is related to the performance of the protective system determined by the first and second stage of protection. For the rated short-circuit current equal or higher than 40 kA, during the first stage of protection (0.1 s), no external effects on enclosure other than the operation of pressure relief device is permitted. During the second stage of protection (≤0.3 s) no fragmentation is permitted, but burn-through is acceptable. The test should be carried out on the GIS compartment with the smallest volume at nominal gas pressure. Since a newly developed GIS 145 kV is designed as a three-phase encapsulated, arc initiation is achieved by short connecting of all three phase conductors in the vicinity of a partition by means of a thin metal wire. This ensures that two electric arcs burn simultaneously commutating between the phases, so the possibility of enclosure burn-through in this type of GIS is minimized. In order to prevent the release of SF6 gas in the atmosphere during the testing, a test enclosure should be placed in a protective gastight enclosure filled with air or more often SF6 gas at pressure of 0.1 MPa. This test object configuration significantly complicates the pressure rise calculation and increases the testing cost. In order to prevent enclosure fragmentation, the pressure difference between the test enclosure and the protective enclosure during the test should always be less than the bursting pressure of test enclosure. Also, the protective enclosure should be designed to withstand the maximum pressure rise that may occur after pressure relief device opens. In order to assess the likelihood of passing the upcoming type test for newly developed GIS, a computer program for calculation of pressure and temperature in the test enclosure and protective enclosure was developed. The mathematical model is based on the paper of the working group CIGRE A3.24, published in 2014. The basic model shown in the paper is enhanced by the real properties of the SF6 gas/plasma, evaporation of the electrode material and the insulator ablation. The contribution of exothermic/endothermic reactions between the gas and the electrode material on the pressure and temperature rise was also considered. At the same time, the measurements of pressure rise in GIS enclosure and protective enclosure were carried out in Končar High Power Laboratory. The experiments performed on a copper and aluminum electrodes in SF6 gas confirmed significantly higher contribution of aluminum electrodes to the pressure and temperature rise compared to the copper electrodes. The computer program is verified by measurement results

    Single Color Centers Implanted in Diamond Nanostructures

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    The development of materials processing techniques for optical diamond nanostructures containing a single color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20nm) to generate Nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal. Individual NV centers are then isolated mechanically by dry etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1\mu m) implantation of individual NV centers into pre-fabricated diamond nanowire. The high single photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allows us to sustain strong photon anti-bunching even at high pump powers.Comment: 20 pages, 7 figure

    Influence of working fluid on ORC with low temperature geothermal source – Case study geothermal power plant “Babina Greda”

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    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In 1998 the Energy Institute “Hrvoje Požar” prepared a Program of Geothermal Energy Usage in the Republic of Croatia, which shows that in the Republic of Croatia there are some low/medium temperature geothermal sources (geothermal water) in the range from 100 to 170 ºC, by means of which it is possible to produce electricity in binary plants, either with the Organic Rankine Cycle (ORC) or with the Kalina cycle. However concrete initiatives for the construction of geothermal power plants have only recently been started. In accordance with this authors in previous papers have presented result of an energy-exergy analysis of geothermal resources Velika Ciglena (175 ºC), Lunjkovec-Kutnjak (140 ºC), Babina Greda (125 ºC) and Rečica (120 ºC), in order to determine which cycle is better for the conditions in Croatia. The analysis results have shown that the ORC with isopentane as working fluid is thermodynamically better from the Kalina cycle for temperatures of all cited geothermal sources and cooling air, and considering the problems that all the new technologies as Kalina cycle encounter in their early phase of application, authors propose the application of binary plants using ORC cycle for all low/medium temperature geothermal sources in the Republic of Croatia. Researches related to the application of the ORC generally deals with the selection of the working fluid, optimization of the ORC unit and the whole plant and analysis of possible modifications with aim to increase its thermodynamic efficiency or net mechanical power output. Although in the available literature, there are a large number of published research results on the selection of the working fluid, however, every geothermal source is a case for itself with respect to the temperature of geothermal water and the cooling fluid on location (water or air). Therefore, in this paper will be presented the results of analysis of the working fluid influence on both thermodynamic efficiency and useful work and others plant characteristics for the case of Geothermal Power Plant “Babina Greda” with lower temperature of geothermal water - 125 ºC. As the working fluid the next refrigerants and hydrocarbons will be analyzed: R236fa, toluene, R365mfc, R236ea, C5F12, hexane, R123, R245ca, R245fa, R21, R114, R113, R12, R11, R152a, R142b, R141b, R600a, R600, R601a and R601.dc201

    Alcoholism and Depression

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    Alcoholism and depression are entangled in many ways and appear in many combinations. In spite of this fact, to this problem is rarely given sufficient attention which results in poor diagnostic and inadequate therapeutic approach with all the consequences this engenders. The frequency of depression in alcoholics is investigated here with the object of finding out to what extent it can be successfully diagnosed and medically treated. The research was carried out in the Psychiatric Clinic of the Clinical Hospital »Split« and the sample of examinees included the patients treated in the stationary part of the Clinic and in the daily hospital

    Integrated TiO2 resonators for visible photonics

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    We demonstrate waveguide-coupled titanium dioxide (TiO2) racetrack resonators with loaded quality factors of 2x10^4 for the visible wavelengths. The structures were fabricated in sputtered TiO2 thin films on oxidized silicon substrates using standard top-down nanofabrication techniques, and passively probed in transmission measurements using a tunable red laser. Devices based on this material could serve as integrated optical elements as well as passive platforms for coupling to visible quantum emitters.Comment: 4 pages, 3 figure

    EFFECT OF SEASON ON VARIATION IN SOMATIC CELL COUNT IN MILK

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    Broj somatskih stanica u mlijeku pokazatelj je higijenske kvalitete mlijeka i opći indikator zdravlja vimena. Njihov povećan broj je pouzdan znak poremećaja zdravlja krava ili higijensko-sanitarnih uvjeta proizvodnje. U cilju povećanja proizvodnje mlijeka te s obzirom na čitav niz čimbenika koji mogu utjecati na variranje broja somatskih stanica vrlo je važno poznavanje njihovog utjecaja u našim proizvodnim uvjetima. U ovom radu su prikazani rezultati analiza broja somatskih stanica od 395.299 uzoraka mlijeka u razdoblju od 2000. do 2008. godine. Testiran je utjecaj sezone (godišnje doba) na broj somatskih stanica u mlijeku. Rezultati istraživanja pokazuju značajno variranje broja somatskih stanica tijekom razdoblja 2000.-2008. godine. S izuzetkom 2003. i 2004. godine može se uočiti trend postepenog smanjenja broja somatskih stanica, koji je najvjerojatnije posljedica donošenja zakonskih propisa koji uređuju to područje (Pravilnika o kakvoći svježeg sirovog mlijeka i Uredbe o ciljnoj cijeni svježeg sirovog mlijeka) odnosno utjecaja broja somatskih stanica na formiranje otkupne cijene mlijeka. Nadalje, utvrđeno je da sezona (godišnje doba) ima značajnog utjecaja na variranje broja somatskih stanica u mlijeku. U našim klimatskim uvjetima povećan broj somatskih stanica uočen je u ljetnim i jesenskim mjesecima, a niži u proljetnim i zimskim mjesecima što je najvjerojatnije posljedica visokih temperatura i vlage u tim razdobljima godine.The number of somatic cells in milk is an indicator of hygienic quality of milk and a general indicator of udder health. The increase in their number is a reliable sign of impaired health or cow health and sanitary conditions of production. In order to increase milk production and with regard to a number of factors that can affect the variation of somatic cells is very important to know their impact in terms of our production conditions. This paper presents the results of the analysis of somatic cell count of 395,299 milk samples in the period from 2000 – 2008. It was tested the effect of season on the number of somatic cells in milk. The study results show a significant variation of somatic cells during period 2000th-2008th year. With the exception of the year 2003 and 2004 the trend can be seen a gradual reduction in the number of somatic cells, which is probably the result of the adoption of legislation governing this area (Ordinance on the quality of fresh raw milk and the Regulation on the target price of the fresh raw milk) and the impact of somatic cells in the formation of the price of milk. Furthermore, it was found that the season has a significant effect on the variation of the number of somatic cells in milk. In our climatic conditions, increased number of somatic cells was observed in the summer and autumn and lower in the spring and winter, it is most likely a result of high temperatures and humidity in those periods of the year
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