TPC tracking and particle identification in high-density environment

Track finding and fitting algorithm in the ALICE Time projection chamber (TPC) based on Kalman-filtering is presented. Implementation of particle identification (PID) using d$E$/d$x$ measurement is discussed. Filtering and PID algorithm is able to cope with non-Gaussian noise as well as with ambiguous measurements in a high-density environment. The occupancy can reach up to 40% and due to the overlaps, often the points along the track are lost and others are significantly displaced. In the present algorithm, first, clusters are found and the space points are reconstructed. The shape of a cluster provides information about overlap factor. Fast spline unfolding algorithm is applied for points with distorted shapes. Then, the expected space point error is estimated using information about the cluster shape and track parameters. Furthermore, available information about local track overlap is used. Tests are performed on simulation data sets to validate the analysis and to gain practical experience with the algorithm.Comment: 9 pages, 5 figure

An Achromatic Focal Plane Mask for High-Performance Broadband Coronagraphy

Developments in coronagraph technology are close to achieving the technical requirements necessary to observe the faint signal of an Earth-like exoplanet in monochromatic light. An important remaining technological challenge is to achieve high contrast in broadband light. Coronagraph bandwidth is largely limited by chromaticity of the focal plane mask, which is responsible for blocking the stellar PSF. The size of a stellar PSF scales linearly with wavelength; ideally, the size of the focal plane mask would also scale with wavelength. A conventional hard-edge focal plane mask has a fixed size, normally sized for the longest wavelength in the observational band to avoid starlight leakage. The conventional mask is oversized for shorter wavelengths and blocks useful discovery space. We present a new focal plane mask which operates conceptually as an opaque disk occulter, but uses a phase mask technique to improve performance and solve the "size chromaticity" problem. This achromatic focal plane mask would maximize the potential planet detection space without allowing starlight leakage to degrade the system contrast. Compared with a conventional opaque disk focal plane mask, the achromatic mask allows coronagraph operation over a broader range of wavelengths and allows the detection of exoplanets closer to their host star. We present the generalized design for the achromatic focal plane mask, implementation within the Subaru Coronagraph Extreme Adaptive Optics instrument, and laboratory results which demonstrate the size-scaling property of the mask

Speckle Control with a remapped-pupil PIAA-coronagraph

The PIAA is a now well demonstrated high contrast technique that uses an intermediate remapping of the pupil for high contrast coronagraphy (apodization), before restoring it to recover classical imaging capabilities. This paper presents the first demonstration of complete speckle control loop with one such PIAA coronagraph. We show the presence of a complete set of remapping optics (the so-called PIAA and matching inverse PIAA) is transparent to the wavefront control algorithm. Simple focal plane based wavefront control algorithms can thus be employed, without the need to model remapping effects. Using the Subaru Coronagraphic Extreme AO (SCExAO) instrument built for the Subaru Telescope, we show that a complete PIAA-coronagraph is compatible with a simple implementation of a speckle nulling technique, and demonstrate the benefit of the PIAA for high contrast imaging at small angular separation.Comment: 6 figures, submitted to PAS

Large XCH 4 anomaly in summer 2013 over northeast Asia observed by GOSAT

Extremely high levels of column-averaged dry-air mole fractions of atmospheric methane (XCH4) were detected in August and September 2013 over northeast Asia (∼  20 ppb above the averaged summertime XCH4 over 2009–2012, after removing a long-term trend), as being retrieved from the Short-Wavelength InfraRed (SWIR) spectral data observed with the Thermal And Near-infrared Sensor for carbon Observation – Fourier Transform Spectrometer (TANSO-FTS) onboard Greenhouse Gases Observing Satellite (GOSAT). Similar enhancements of XCH4 were also observed by the ground-based measurements at two Total Carbon Column Observing Network (TCCON) sites in Japan

Polarization of Tau Leptons Produced in Quasielastic Neutrino--Nucleon Scattering

A numerical analysis of the polarization vector of tau leptons produced through quasielastic neutrino and antineutrino interactions with free nucleons is given with two models for vector electromagnetic form factors of proton and neutron. The impact of G parity violating axial and vector second-class currents is investigated by applying a simple heuristic model for the induced scalar and tensor form factors.Comment: Thesis of a talk given at the 8th Scientific Conference (SCYSS-04), Dubna, Russia, 2 - 6 Feb 2004. 11 pages, 6 figures; added references, figures and discussion; conclusions unchange

Experimental study of module of the thermal hydraulic actuator

Проведено експериментальне дослідження роботи модуля теплового гідроприводу при підведенні теплового потоку постійної потужності. Отримано експериментальні характеристики зміни температур у крайніх точках осьового перерізу камери розширення і експериментальну характеристику ходу штовхача (сильфону) в період підведення теплової енергії до модуля та в період вільного охолодження. Виконано аналіз результатів експериментального дослідження, встановлено особливості модуля теплового гідроприводу.Purpose. The characteristics of the module during the supply of heat and time return the module to its original state was studied. Design/methodology/approach. We investigated the characteristics of the thermal hydraulic module. The experimental characteristics of the temperature change at the extremal points for axial section of the expansion chamber at the period of receiving the constant power heat flow and for the cooling period was obtained. The pusher’s displacement characteristics for the same conditions were obtained too. Some of the features for thermal hydraulic module were seted. Findings. The агтсешщтштп of the module are strongly influenced by the exploitative conditions. Also updated accounting of certain processes in the module. Originality/value. The experimental characteristics of the module, which can be used to verify and refine the mathematical model were analized. It allows to take into account the influence of the environment on the characteristics of the thermal hydraulic actuator at the design stage.Проведено экспериментальное исследование работы модуля теплового гидропривода при подведении теплового потока постоянной мощности. Получены экспериментальные характеристики изменения температур в крайних точках осевого сечения камеры расширения, а также экспериментальные характеристики хода толкателя (сильфона) в период подведения тепловой энергии к модулю и в период его охлаждения. Выполнен анализ результатов экспериментального исследования, установлены особенности модуля теплового гидропривода

Academic Librarians Examination of University Students’ and Faculty’s Perceptions of Open Educational Resources

A survey of 2,574 students and 1,157 faculty members across ten institutions of postsecondary education in the state of Utah was conducted by the Utah Academic Libraries Consortium. Survey items were created to understand the influence of textbook costs on student academic behavior and the viability of faculty adopting open educational resources (OER) as a solution to the cost of textbooks and the possible need for librarian support of OER. Two-year and four-year institutions were compared to identify differences that might exist between them. Most students felt that their academic success was negatively impacted by textbook cost, particularly at two-year institutions where students registered for fewer courses because of associated textbook costs. Faculty survey findings showed that adjunct professors were more likely to require a traditionally copyright-restricted textbook. Approximately 90% of participants indicated they would be willing to use suitable OER for their course, and almost half of survey participants expressed a desire for help finding these resources

Тепловой гидравлический привод

Розглянуто типові конструктивні схеми гідравлічних приводів обертання. Розглянуті конструкції модулів теплового гідроприводу. Визначені основні конструктивні параметри, що впливають на вихідні характеристики та роботу приводу. Розглянуто ряд рідин, які можуть бути використані в якості робочого тіла для теплового гідроприводу. Розглянуто процеси, що відбуваються в тепловому гідроприводі на прикладі одного модуля. Проведено експерименти для дослідження величини теплового розширення робочої рідини. На основі отриманих даних проведено розрахунок параметрів холостого ходу модуля.Purpose. Justification of the possibility of using the thermal hydraulic actuator as tracker in solar power systems, design of the rational construction of actuator and development of mathematical tools for prediction its characteristics. Design/methodology/approach. The design and principle of known trackers of solar power systems were considered. The overview of design and principle of thermal actuators carried out. Ability of fluids to expand by influence of temperatures was chosen as principle for the thermal hydraulic actuator. The working fluid of the module of the thermal hydraulic actuator to produce necessary pusher’s displacement was selected. The expansion of the working fluid depends of its temperature was investigated by experimental research. There is theoretical calculation based on experimental data for prediction parameters of idling of the module of the thermal hydraulic actuator were performed. Findings. It is found that there are possibilities of using the thermal hydraulic actuator that based on the thermal volumetric expansion of the working fluid as tracker for the solar power systems. Originality/value. Using of the thermal hydraulic actuator in the solar power system makes possible positioning of receiver without consuming of electrical energy. It leads to more efficiency work of the solar power system.Рассмотрены типовые конструктивные схемы гидравлических приводов вращения. Рассмотрены конструкции модулей теплового гидропривода. Определены основные конструктивные параметры, влияющие на выходные характеристики и работу привода. Рассмотрен ряд жидкостей, которые могут быть использованы в качестве рабочего тела для модулей теплового гидропривода. Рассмотрены процессы, которые происходят в тепловом гидроприводе на примере работы одного модуля. Проведены эксперименты по исследованию величины теплового расширения рабочей жидкости. Проведен расчет параметров холостого хода для модуля