176 research outputs found

    Simulation and Efficiency Studies of Optical Photon Transportation and Detection with Plastic Antineutrino Detector Modules

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    In this work, the simulation of optical photons is carried out in an antineutrino detector module consisting of a plastic scintillator connected to light guides and photomultipliers on both ends, which is considered to be used for remote reactor monitoring in the field of nuclear safety. Using Monte Carlo (MC) based GEANT4 simulation, numerous parameters influencing the light collection and thereby the energy resolution of the antineutrino detector module are studied: e.g., degrees of scintillator surface roughness, reflector type, and its ap- plying method onto scintillator and light guide surface, the reflectivity of the reflector, light guide geometries and diameter of the photocathode. The impact of each parameter is inves- tigated by looking at the detected spectrum, i.e. the number photoelectrons per depositing energy. In addition, the average light collection efficiency of the detector module and its spatial variation are calculated for each simulation setup. According to the simulation re- sults, it is found that photocathode size, light guide shape, reflectivity of reflecting material and wrapping method show a significant impact on the light collection efficiency while scin- tillator surface polishing level and the choose of reflector type show relatively less impact. This study demonstrates that these parameters are very important in the design of plastic scintillator included antineutrino detectors to improve the energy resolution efficiency

    Comparison of Plastic Antineutrino Detector Designs in the Context of Near Field Reactor Monitoring

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    We compare existing segmented plastic antineutrino detectors with our new geometrically improved design for antineutrino detection and light collection efficiency. The purpose of this study is to determine the most suitable design style for remote reactor monitoring in the context of nuclear safeguards. Using Monte Carlo based GEANT4 simulation package, we perform detector simulation based on two prominent experiments: Plastic antineutrino detector array (Panda) and Core monitoring by reactor antineutrino detector (Cormorad). In addition to these two well-known designs, another concept, the Panda2, can be obtained by making a small variation of Panda detector, is also considered in the simulation. The results show that the light collection efficiency of the Cormorad is substantially less with respect to the other two detectors while the highest antineutrino detection efficiency is achieved with the Cormorad and Panda2. Furthermore, as an alternative to these design choices, which are composed of an array of identical rectangular-shaped modules, we propose to combine regular hexagonal-shaped modules which minimizes the surface area of the whole detector and consequently reduces the number of optical readout channels considerably. With this approach, it is possible to obtain a detector configuration with a slightly higher detection efficiency with respect to the Panda design and a better energy resolution detector compared to the Cormorad design

    SOLVABILITY OF BOUNDARY VALUE PROBLEMS WITH TRANSMISSION CONDITIONS FOR DISCONTINUOUS ELLIPTIC DIFFERENTIAL OPERATOR EQUATIONS

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    We consider nonlocal boundary value problems which includes discontinuous coefficients elliptic differential operator equations of the second order and nonlocal boundary conditions together with boundary-transmission conditions. We prove coerciveness and Fredholmness for these nonlocal boundary value problems

    Real effects of inflation uncertainty in the US

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    We empirically investigate the effects of inflation uncertainty on output growth for the US using both monthly and quarterly data over 1985-2009. Employing a Markov regime switching approach to model output dynamics, we show that inflation uncertainty obtained from a Markov regime switching GARCH model exerts a negative and regime dependant impact on output growth. In particular, we show that the negative impact of inflation uncertainty on output growth is almost 4.5 times higher during the low growth regime than that during the high growth regime. We verify the robustness of our findings using quarterly dataGrowth, inflation uncertainty, Markov-switching modeling, Markov-switching GARCH

    Malathion Kaynakl─▒ Mide Toksisitesinde Rutinin Koruyucu Etkisi: Oksidatif Stres, Enflamasyon ve Apoptozun De─čerlendirilmesi

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    Malathion (MLT) is widely used as an insecticide in agricultural, veterinary, medicinal, and public health applications. MLT is taken up by the body through the skin, respiratory, and gastrointestinal systems. Rutin (RUT) is a powerful, naturally occurring antioxidant molecule isolated from citrus fruits with low toxicity and powerful anti-oxidant capabilities. The aim of this study was to investigate the protective effects of RUT against MLT-induced gastric toxicity. For this purpose, rats were randomly divided into 5 groups, with 7 animals in each group. Rats were administered orally 100 mg/kg MLT and 50 mg/kg and 100 mg/kg RUT for 28 days. According to the results obtained, while MLT caused lipid peroxidation by increasing malondialdehyde (MDA) levels, it also suppressed antioxidant capacity by decreasing superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) enzyme activities and lowering glutathione (GSH) levels. RUT application decreased the severity of lipid peroxidation and tried to increase antioxidant capacity. In addition, in rats administered MLT, it was determined that inflammation was caused by the increase in nuclear factor kappa B (NF-╬║B), tumor necrosis factor-alpha (TNF╬▒), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) mRNA transcript levels, and that the severity of inflammation decreased in a dose-dependent manner with RUT application. When apoptosis, another measured panel, was evaluated, it was determined that the Bax level increased while Bcl-2 decreased as a result of toxicity induced by MLT. However, with the RUT application, it was determined that these parameters had the opposite effect and approached the control group values. When all the results are evaluated, it can be said that RUT application has protective effects on MLT-induced gastric toxicity.Malathion (MLT), tar─▒m, veterinerlik, t─▒p ve halk sa─čl─▒─č─▒ uygulamalar─▒nda insektisit olarak yayg─▒n ┼čekilde kullan─▒lmaktad─▒r. MLT cilt, solunum ve gastrointestinal sistem yoluyla v├╝cut taraf─▒ndan al─▒n─▒r. Rutin (RUT), d├╝┼č├╝k toksisiteye ve antioksidan ├Âzelliklere sahip, narenciye meyvelerinden izole edilen g├╝├žl├╝, do─čal olarak olu┼čan bir antioksidan molek├╝ld├╝r. Bu ├žal─▒┼čman─▒n amac─▒ MLT ile olu┼čturulan mide toksisitesinde RUTÔÇÖun koruyucu etkilerini ara┼čt─▒rmakt─▒r. Bu ama├žla ratlar her grupta 7 hayvan olacak ┼čekilde rastgele 5 gruba ayr─▒ld─▒. Ratlar 28 g├╝n boyunca oral olarak 100 mg/kg dozda MLT ve 50 mg/kg ve 100 mg/kg dozda RUT uyguland─▒. Elde edilen sonu├žlara g├Âre MLT, malondialdehit (MDA) seviyesini art─▒rarak lipid peroksidasyona neden olurken ayn─▒ zamanda s├╝peroksit dismutaz (SOD), katalaz (KAT) ve glutatyon peroksidaz (GPx) enzim aktivitelerini azaltarak ve glutatyon (GSH) d├╝zeylerini d├╝┼č├╝rerek antioksidan kapasiteyi bask─▒lad─▒. RUT uygulamas─▒ ise lipid peroksidasyonun ┼čiddetini azaltt─▒ ve antioksidan kapasitenin y├╝kselmesine dene oldu. Buna ek olarak, MLT uygulanan ratlarda nuclear factor kappa B (NF-╬║B), tumor necrosis factor-alpha (TNF╬▒), cyclooxygenase-2 (COX-2) ve inducible nitric oxide synthase (iNOS) mRNA transkript seviyeleri artmas─▒yla inflamasyonun ┼čekillendi─či, RUT uygulamas─▒ ile doza ba─č─▒ml─▒ olarak inflamasyonun ┼čiddetinin azald─▒─č─▒ tespit edildi. ├ľl├ž├╝len panellerden bir di─čeri olan apoptoz de─čerlendirildi─činde, MLT ile ind├╝klenen mide toksisitesi sonucunda Bax seviyesi artarken Bcl-2ÔÇÖnin azald─▒─č─▒ belirlendi. Bunula beraber RUT uygulamas─▒ ile bu parametrelerin ters etki g├Âstererek kontrol grubu de─čerlerine yakla┼čt─▒─č─▒ tespit edildi. T├╝m sonu├žlar de─čerlendirildi─činde RUT uygulamas─▒n─▒n MLTÔÇÖnin neden oldu─ču mide toksisitesi ├╝zerine koruyucu etkileri oldu─ču s├Âylenebilir

    A reactor antineutrino detector based on hexagonal scintillator bars

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    This study presents a new concept of segmented antineutrino detector based on hexagonal plastic scintillator bars for detecting antineutrinos from a nuclear reactor core. The choice of hexagonal scintillator bars is original and provides compactness. The proposed detector detects antineutrinos via inverse beta decay (IBD) with the prompt-delayed double coincidence. Owing to its segmented structure, the background, which satisfies the delayed coincidence condition can be eliminated by applying proper event selection cuts. In this manner, the main focus is to determine proper selection criteria to precisely tag the true IBD events. Monte-Carlo simulation is carried out to understand the characteristic of the IBD interaction in the proposed detector by using Geant4 toolkit. A set of event selection criteria is established based on the simulated data. It is found that a detection efficiency of 10 % can be achieved with the selection condition applied. It is also shown that fast neutrons, which constitute the main background source for above-ground detection, can be effectively eliminated with these selection criteria. The motivation for this study is to install this compact detector at a short distance (<100 m) from the Akkuyu Nuclear Power Plant, which is expected to start operation in 2023.Comment: 17 pages,13 figure

    Dynamic model and control of a new quadrotor unmanned aerial vehicle with tilt-wing mechanism

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    In this work a dynamic model of a new quadrotor aerial vehicle that is equipped with a tilt-wing mechanism is presented. The vehicle has the capabilities of vertical take-off/landing (VTOL) like a helicopter and flying horizontal like an airplane. Dynamic model of the vehicle is derived both for vertical and horizontal flight modes using Newton-Euler formulation. An LQR controller for the vertical flight mode has also been developed and its performance has been tested with several simulations

    Modeling and position control of a new quad-rotor unmanned aerial vehicle with tilt-wing mechanism

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    In this work a dynamic model of a new quadrotor aerial vehicle that is equipped with a tilt-wing mechanism is presented. The vehicle has the capabilities of vertical take-off/landing (VTOL) like a helicopter and flying horizontal like an airplane. Dynamic model of the vehicle is derived both for vertical and horizontal flight modes using Newton-Euler formulation. An LQR controller for the vertical flight mode has also been developed and its performance has been tested with several simulations

    A New Perspective On Soft Topology

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    In this paper, we approach the concept of soft topology with a different perspective. We define a soft topological space over given initial topological universe as a parameterization of subspaces of a topological space. In addition to this, we define some basic topological concepts such as Hausdorffness, compactness, connectedness for soft topological spaces and study their some properties. We give some results for relations between a topological space and a soft topological space that is defined on it

    Mathematical modeling and vertical flight control of a tilt-wing UAV

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    This paper presents a mathematical model and vertical flight control algorithms for a new tilt-wing unmanned aerial vehicle (UAV). The vehicle is capable of vertical take-off and landing (VTOL). Due to its tilt-wing structure, it can also fly horizontally. The mathematical model of the vehicle is obtained using Newton-Euler formulation. A gravity compensated PID controller is designed for altitude control, and three PID controllers are designed for attitude stabilization of the vehicle. Performances of these controllers are found to be quite satisfactory as demonstrated by indoor and outdoor flight experiments
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