Alignment and resolution studies of a MARS CT scanner

This paper describes a procedure of alignment of MARS CT scanner with cone beam geometry. The position of the xray source relative to the detector, the tilt of the detector are measured during alignment. The mechanical precision of gantry movement is determined. Significant improvement in the quality of image reconstruction has been achieved as a result of the calibration. Spatial resolution (PTF) of the scanner is confirmed to be about 30 μm

Spectroscopic studies of defects in gamma- and neutron-irradiated magnesium aluminates spinel ceramics

The spectroscopic investigations of defects in optical spinel ceramics irradiated with gamma-rays from ⁶⁰Co source and mixed neutron-gamma field in WWR reactor to neutron fluences of 1·10¹³ and 5·10¹³ n/cm² were provided. The obtained data on the dose dependence of intensity of absorption bands in the visible range allow to identify the origin of optical centers formed under irradiation. Absorption in IR range indicates on the presence in ceramics carbon-related complexes that become active after irradiation. The registered EPR signal of g = (2.0174±0.0005) and width of (46.1±1.5) G which corresponds to HO₂⁻ or O₃⁻ radicals. The dependences of the investigated centers on annealing temperature of the irradiated spinel ceramics show unusual increase in intensity of absorption and steady-state radio-luminescence in the temperature range of 200…400 °C. The role of complexes of defects including anti-site defects in formation and healing of defects in different temperature ranges are analyzed taking into account different mobility of cations and anions and specific mechanism of radio-luminescence.Проведені спектроскопічні дослідження в оптичній кераміці шпінелі, опроміненій гамма-променями джерела ⁶⁰Co та змішаним гамма-нейтронним потоком у ВВР реакторі при потоках нейтронів 1·10¹³ та 5·10¹³ нейтр./см². Одержані дані із залежності інтенсивності смуг поглинання у видимій області дозволили ідентифікувати природу оптичних центрів, створених опромінюванням. Поглинання світла в інфрачервоній області вказує на присутність у кераміці комплексів, що містять вуглець та стають оптично активними після опромінення. Зареєстрований сигнал ЕПР з g = (2.0174 ±0.0005) і шириною (46.1±1.5) Гс, що відповідає HO₂⁻ - або O₃⁻ -радикалам. Залежність досліджених центрів від температури відпалу в опроміненій кераміці шпінелі демонструє незвичайне збільшення інтенсивності поглинання та стаціонарної люмінесценції в інтервалі температур 200…400 °C. Проаналізована роль комплексів дефектів, які включають дефекти антиструктури в створенні та відпалу дефектів у різних температурних областях з урахуванням різної рухливості катіонів та аніонів, а також специфіки механізму рентегнолюмінесценції.Проведены спектроскопические исследования оптической керамики шпинели, облученной гамма-квантами источника ⁶⁰Co и смешанным гамма-нейтронным потоком в реакторе ВВР при потоках нейтронов 1·10¹³ и 5·10¹³ нейтр./см². Полученные данные из зависимости интенсивности полос поглощения в видимой области позволили определить природу оптических центров, созданных облучением. Поглощение света в инфракрасной области указывает на присутствие в керамике углеродсодержащих комплексов, которые становятся оптически активными после облучения. Зарегистрированный сигнал ЭПР с g = (2.0174 ±0.0005) и шириной (46.1±1.5) Гс, соответствующий HO₂⁻ - или O₃⁻ -радикалам. Зависимость концентраций исследованных центров от температуры отжига в облученной керамике шпинели демонстрирует необычный рост интенсивности поглощения и стационарной люминесценции в интервале температур 200…400 °C. Проанализирована роль комплексов дефектов, которые включают дефекты антиструктуры в образовании и отжиге дефектов в различных температурных областях с учетом различной подвижности катионов и анионов, а также специфики механизма рентгенолюминесценции

The place of millet in food globalization during Late Prehistory as evidenced by new bioarchaeological data from the Caucasus

Two millets, Panicum miliaceum and Setaria italica, were domesticated in northern China, around 6000 BC. Although its oldest evidence is in Asia, possible independent domestication of these species in the Caucasus has often been proposed. To verify this hypothesis, a multiproxy research program (Orimil) was designed to detect the first evidence of millet in this region. It included a critical review of the occurrence of archaeological millet in the Caucasus, up to Antiquity; isotopic analyses of human and animal bones and charred grains; and radiocarbon dating of millet grains from archaeological contexts dated from the Early Bronze Age (3500–2500 BC) to the 1st Century BC. The results show that these two cereals were cultivated during the Middle Bronze Age (MBA), around 2000–1800 BC, especially Setaria italica which is the most ancient millet found in Georgia. Isotopic analyses also show a significant enrichment in 13C in human and animal tissues, indicating an increasing C4 plants consumption at the same period. More broadly, our results assert that millet was not present in the Caucasus in the Neolithic period. Its arrival in the region, based on existing data in Eurasia, was from the south, without excluding a possible local domestication of Setaria italica

Production And Study Of Bio Gazolines

Combustible ethanol was obtained from agricultural waste. Test samplesE0 (petrolgazoline) and E5, E10 and E20 (epanpl/gazoline blend) were prepared and their physical, chemical and technical characteristics were studied. The effect of bioethanol on the ecological compatibility of the automobile engine has been studied. The objects of research were Regular, Premium and Super of Petrol gasoline Samples, as well as a of 10%, 20% and 30%. bioethanol/gazoline blends. The study of the ecological properties of the test additive was carried out at the stand of automobile engines SAK-670 (Germany), on which the engine of a BMW-316 car with coupling sleeve and a transmission assembly is installed. The stand is equipped with brakes and torque sensors, as well as with crankshaft speed and fuel consumption measuring instruments. The test mixtures during an idle running of engine cause a decrease in the CO content in the exhaust gases by 10-16%, and this taking into account their low cost, indicate the prospect of expanding the use of fuel ethanol

Study of tribotechnical and ecological efficiency of motor car transmission oil “Kolkheti–2” prepared with nanotechnology

The paper refers to the research results of influence of motor car transmission oil prepared with nanotechnology on pitting resistance of friction knots and engine fuel consumption. herewith the advantage of test oils compared to corresponding oils of famous firms is shown

Diluted Magnetic Semiconductor Investigations in Ukraine. Nature of Some Additional Lines in QW Optical Spectra

The general review of the history and present-day situation of diluted magnetic semiconductor investigation in Ukraine is given by S. Ryabchenko. Some noteworthy results of diluted magnetic semiconductor investigation obtained in Ukraine are pointed out. The main features of the present day situation are mentioned also. As an example of last diluted magnetic semiconductor investigations, the new result obtained by Abramishvili, Komarov, Ryabchenko, Semenov, Kyrychenko and Dubowski for Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te quantum well structures grown by laser ablation method are presented. A weak additional line was observed in the reflectivity spectra of a 27 Å wide quantum well with x= 0.11 in the barrier. Such additional line has not been observed in spectra of similar molecular beam epitaxy grown structures. Based on the theoretical computations of the energies and the relation of intensities of the main and additional lines we conclude that this line might be associated with hh2 → e1 transitions, which ceases to be forbidden in the presence of technologically caused asymmetry of quantum well potential profile

Study of tribological efficiency of new type additive to oils

2-s2.0-84905815557 - ScopusHigh tribological efficiency of amorphous finely dispersed carbon (AFDC) received in the form of waste during methane pyrolysis (CMP) has been shown earlier. The multifunctional mechanism of its action is based on the new phenomenon, which consists in AFDC ability to form in the process of friction secondary surface structures, containing phases of nano-dispersed diamond, graphite, AFDC and providing high functional properties of oils containing CMP. By means of studies carried out in the mentioned aspect a new high effective multifunctional additive to oils is revealed, which represents synthesized amorphous nano-dispersed carbon doped by ironVytauto Didžiojo universitetasŽemės ūkio akademij