38 research outputs found

    Исследование влияния ионизирующего излучения высокоэнергетических ионов гелия на процессы формирования протон-проводящих свойств полимерных фторсодержащих функциональных трековых мембран

    Get PDF
    Объект исследования-полимерная пленка ПВДФ и прививаемый мономер–стирол, обладающий сшивающими свойствами при модификации. Цель работы–синтез протон-проводящих мембран путем модифицирования пленок ПВДФ сульфированным полистиролом и установление влияния наполнителей на их транспортные и физико-химические свойства. В процессе проводились теоретические и экспериментальные работы по радиационно-химической полимеризации стирола в матрицу ПВДФ с последующим сульфированием полимерного композита, по определению обменной емкости и протонной проводимости мембран. В результате получена ППМ путем матричной полимеризации ПВДФ ионизующимся мономером. Результаты представляют интерес для понимания процессов матричной полимеризации ионизующихся мономеров и могут являться основой для создания полимерных сисThe object of study-polymer film PVDF and grafting monomer is styrene, having crosslinking properties when enchanted. Purpose–synthesis of proton-conducting membranes by the modification of the PVDF films of sulfonated polystyrene and evaluation of the influence of fillers on the transport and their physico-chemical properties. The process was carried out work on radiation-chemical polymerization of styrene in a matrix of PVDF with subsequent by sulfonation polymer composite, by definition, exchange capacity and proton conductivity of the membranes. The result is PCM by matrix polymerization of PVDF ionizable monomer. The results are of interest for understanding the processes matrix polymerization of ionizable monomers and may be the basis for the creation of polymer systems

    Automated computer-based detection of encounter behaviours in groups of honeybees.

    Get PDF
    Honeybees form societies in which thousands of members integrate their behaviours to act as a single functional unit. We have little knowledge on how the collaborative features are regulated by workers' activities because we lack methods that enable collection of simultaneous and continuous behavioural information for each worker bee. In this study, we introduce the Bee Behavioral Annotation System (BBAS), which enables the automated detection of bees' behaviours in small observation hives. Continuous information on position and orientation were obtained by marking worker bees with 2D barcodes in a small observation hive. We computed behavioural and social features from the tracking information to train a behaviour classifier for encounter behaviours (interaction of workers via antennation) using a machine learning-based system. The classifier correctly detected 93% of the encounter behaviours in a group of bees, whereas 13% of the falsely classified behaviours were unrelated to encounter behaviours. The possibility of building accurate classifiers for automatically annotating behaviours may allow for the examination of individual behaviours of worker bees in the social environments of small observation hives. We envisage that BBAS will be a powerful tool for detecting the effects of experimental manipulation of social attributes and sub-lethal effects of pesticides on behaviour

    Neutron-induced background in the CONUS experiment

    Full text link
    CONUS is a novel experiment aiming at detecting elastic neutrino nucleus scattering in the fully coherent regime using high-purity Germanium (Ge) detectors and a reactor as antineutrino (νˉ\bar\nu) source. The detector setup is installed at the commercial nuclear power plant in Brokdorf, Germany, at a very small distance to the reactor core in order to guarantee a high flux of more than 1013νˉ^{13}\bar\nu/(s\cdotcm2^2). For the experiment, a good understanding of neutron-induced background events is required, as the neutron recoil signals can mimic the predicted neutrino interactions. Especially neutron-induced events correlated with the thermal power generation are troublesome for CONUS. On-site measurements revealed the presence of a thermal power correlated, highly thermalized neutron field with a fluence rate of (745±\pm30)cm2^{-2}d1^{-1}. These neutrons that are produced by nuclear fission inside the reactor core, are reduced by a factor of \sim1020^{20} on their way to the CONUS shield. With a high-purity Ge detector without shield the γ\gamma-ray background was examined including highly thermal power correlated 16^{16}N decay products as well as γ\gamma-lines from neutron capture. Using the measured neutron spectrum as input, it was shown, with the help of Monte Carlo simulations, that the thermal power correlated field is successfully mitigated by the installed CONUS shield. The reactor-induced background contribution in the region of interest is exceeded by the expected signal by at least one order of magnitude assuming a realistic ionization quenching factor of 0.2.Comment: 28 pages, 28 figure

    Constraints on elastic neutrino nucleus scattering in the fully coherent regime from the CONUS experiment

    Get PDF
    We report the best limit on coherent elastic scattering of electron antineutrinos emitted from a nuclear reactor off germanium nuclei. The measurement was performed with the CONUS detectors positioned at 17.1m from the 3.9GWth reactor core of the nuclear power plant in Brokdorf, Germany. The antineutrino energies of less than 10 MeV assure interactions in the fully coherent regime. The analyzed dataset includes 248.7 kgd with the reactor turned on and background data of 58.8 kgd with the reactor off. With a quenching parameter of k = 0.18 for germanium, we determined an upper limit on the number of neutrino events of 85 in the region of interest at 90% confidence level. This new CONUS dataset disfavors quenching parameters above k = 0.27, under the assumption of standard-model-like coherent scattering of the reactor antineutrinos

    Систематизация основ продления сроков использования котлов различной паро производительности

    Get PDF
    Выпускная квалификационная работа 85 страниц, 9 рисунков, 9 таблиц, 34 источника, 1 приложений. Объектом исследования являются паровые котлы выработавшие расчетный срок службы. Цель работы – определить наиболее целесообразный способ замены котлов отработавшего свой срок службы. В процессе исследования проводилась серии исследовательских работ по сбору и систематизации данных, проведение прочностных расчетов. В результате исследования был определен наиболее целесообразный способ использования котлов после окончания срока службы. В данной работе были рассмотрены энергетические котлы ТЭЦ города Северска и ТЭЦ-2 города Барнаула, рассмотренный их параметры, результаты технических диагностирования расчетов на прочность, а так же варианты их модернизация. Проведена экономическая оценка разных ваFinal qualifying work 99 pages, 9 figures, 9 tables, 34 source 1 application. The object of the study are to develop steam boilers design life. Objective - to determine the most appropriate method of replacing spent his life boilers. The study was carried out a series of research works in the collection and organization of data, carrying out strength calculations. The study was determined the most appropriate way to use the boiler after the end of its life. In this work were considered power boilers and CHP city of Seversk СHP-2 of Barnaul, considered their options, the results of technical diagnostics strength calculations, as well as options for their modernization. Spend the economic evaluation of various upgrade options

    First upper limits on neutrino electromagnetic properties from the CONUS experiment

    Get PDF
    We report first constraints on neutrino electromagnetic properties from neutrino-electron scattering using data obtained from the CONUS germanium detectors, i.e. an upper limit on the effective neutrino magnetic moment and an upper limit on the effective neutrino millicharge. The electron antineutrinos are emitted from the 3.9 GWth_\mathrm{th} reactor core of the Brokdorf nuclear power plant in Germany. The CONUS low background detectors are positioned at 17.1 m distance from the reactor core center. The analyzed data set includes 689.1 kg\cdotd collected during reactor ON periods and 131.0 kg\cdotd collected during reactor OFF periods in the energy range of 2 to 8 keV. With the current statistics, we are able to determine an upper limit on the effective neutrino magnetic moment μν<7.51011μB\mu_\nu < 7.5\cdot10^{-11}\,\mu_B at 90% confidence level. From this first magnetic moment limit we can derive an upper bound on the neutrino millicharge of \vertqν<3.31012e0_{\nu}\vert < 3.3\cdot10^{-12}\,e_0

    Full background decomposition of the CONUS experiment

    Get PDF
    The CONUS experiment is searching for coherent elastic neutrino nucleus scattering of reactor anti-neutrinos with four low energy threshold point-contact high-purity germanium spectrometers. An excellent background suppression within the region of interest below 1keV (ionization energy) is absolutely necessary to enable a signal detection. The collected data also make it possible to set limits on various models regarding beyond the standard model physics. These analyses benefit as well from the low background level of ~10d1^{-1}kg1^{-1}below 1keV and at higher energies. The low background level is achieved by employing a compact shell-like shield, that was adapted to the most relevant background sources at the shallow depth location of the experiment: environmental gamma-radiation and muon-induced secondaries. Overall, the compact CONUS shield including the active anti-coincidence muon-veto reduces the background by more than four orders of magnitude. The remaining background is described with validated Monte Carlo simulations which include the detector response. It is the first time that a full background decomposition in germanium operated at reactor-site has been achieved. Next to remaining muon-induced background, 210^{210}Pb within the shield and cryostat end caps, cosmogenic activation and air-borne radon are the most relevant background sources. The reactor-correlated background is negligible within the shield. The validated background model together with the parameterization of the noise are used as input to the likelihood analyses of the various physics cases

    Large-size sub-keV sensitive germanium detectors for the CONUS experiment

    Get PDF
    Intense fluxes of reactor antineutrinos offer a unique possibility to probe the fully coherent character of elastic neutrino scattering off atomic nuclei. In this regard, detectors face the challenge to register tiny recoil energies of a few keV at the maximum. The CONUS experiment was installed in 17.1 m distance from the reactor core of the nuclear power plant in Brokdorf, Germany, and was designed to detect this neutrino interaction channel by using four 1 kg-sized point contact germanium detectors with sub-keV energy thresholds. This report describes the unique specifications addressed to the design, the research and development, and the final production of these detectors. It demonstrates their excellent electronic performance obtained during commissioning under laboratory conditions as well as during the first two years of operation at the reactor site which started on April 1, 2018. It highlights the long-term stability of different detector parameters and the achieved background levels of the germanium detectors inside the CONUS shield setup.Comment: (18 pages, 12 figures
    corecore