398 research outputs found

    L-MOMENTS AND THEIR USE IN MAXIMUM DISCHARGES’ ANALYSIS IN CURVATURE CARPATHIANS REGION

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    This paper aims to present L-moments statistics and their application in analysis of annual maximum discharges series in Curvature Carpathians region, in order: 1) to determine the discordance measure and 2) to identify the regional theoretical distributions most appropriate to the data series in the studied region. The analysis performed allowed: 1) to determine two gauging stations (Mirceşti on Putna River and Moara Domnească on Teleajen River), whose data are discordant comparing with those from the other 41 analyzed stations and 2) to identify three theoretical distributions best fitting maximum annual discharges series: exponential, generalised Pareto and Pearson type 3 distributions

    Mineral waters in Brașov County. Characteristics and use

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    The sources of mineral water are spread all over Braşov County, but most of them have been identified and mapped in the central part of the county, namely at the contact between Transylvanian Depression with the western part of the Eastern Carpathians. Based on the analysis of the mineral water sources identified in the field during 2011 – 2016 period , three major types of mineral waters have been identified: chlorosodic, carbonated and hypothermal waters. Clorosodic waters are present within or close to areas of salt massives (the eastern and south-eastern edge of the Transylvanian Depression), some of these having high salty concentration (more than 70 g/l at Mercheaşa and Racoş). Carbonated mineral waters appear in the southern part of the neogen eruptive, respectively in the unit of the internal Carpathian flysch, on the Zizin-Tărlungeni-Săcele line. Hypothermal waters emerge on the Măieruş-Codlea line, having a constant temperature (23,4ºC at Măieruş and 18,4ºC at Codlea). Some locations with mineral water sources in the Brașov county used to be permanent or seasonal resorts of regional or local importance, many of them being currently abandoned or in an advanced degree of degradation (e.g. Băile Homorod, Băile Zizin, Băile Veneţia de Jos etc.), excepting Băile Rodbav and Băile Perşani which are still active

    LINVIEW: Incremental View Maintenance for Complex Analytical Queries

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    Many analytics tasks and machine learning problems can be naturally expressed by iterative linear algebra programs. In this paper, we study the incremental view maintenance problem for such complex analytical queries. We develop a framework, called LINVIEW, for capturing deltas of linear algebra programs and understanding their computational cost. Linear algebra operations tend to cause an avalanche effect where even very local changes to the input matrices spread out and infect all of the intermediate results and the final view, causing incremental view maintenance to lose its performance benefit over re-evaluation. We develop techniques based on matrix factorizations to contain such epidemics of change. As a consequence, our techniques make incremental view maintenance of linear algebra practical and usually substantially cheaper than re-evaluation. We show, both analytically and experimentally, the usefulness of these techniques when applied to standard analytics tasks. Our evaluation demonstrates the efficiency of LINVIEW in generating parallel incremental programs that outperform re-evaluation techniques by more than an order of magnitude.Comment: 14 pages, SIGMO

    Climate changes and effects on river flow in the Romanian Carpathians

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    The paper highlights some relevant changes detected in Romania, namely in the Carpathian area, and related impacts on streamflow. It focuses on Valea Cerbului River catchment, a small mountainous watershed (extended over 26 km2, in the eastern extremity of the Southern Carpathians), where observed and projected changes of the river flow were presented based on frequency and trend analysis of recorded discharges and on hydrological modeling. As observed changes (between 1950-2010), general upward significant trends in the variability of the average discharge were detected, for both annual and monthly discharges (mostly in October, January and July). The projected changes were estimated by the WaSiM-Eth hydrological model for 2035-2065 period, compared to the reference period 1961-1991 (using climatic data on the A1B scenario obtained within the project ENSEMBLE). The results showed the increase of high flows in the cold season (December − April) and a significant decrease in discharges during the warm season (June − November, mainly in August − September)

    AHTR Mechanical, Structural, and Neutronic Preconceptual Design

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    This report provides an overview of the mechanical, structural, and neutronic aspects of the Advanced High Temperature Reactor (AHTR) design concept. The AHTR is a design concept for a large output Fluoride salt cooled High-temperature Reactor (FHR) that is being developed to enable evaluation of the technology hurdles remaining to be overcome prior to FHRs becoming a commercial reactor class. This report documents the incremental AHTR design maturation performed over the past year and is focused on advancing the design concept to a level of a functional, self-consistent system. The AHTR employs plate type coated particle fuel assemblies with rapid, off-line refueling. Neutronic analysis of the core has confirmed the viability of a 6-month 2-batch cycle with 9 weight-percent enriched uranium fuel. Refueling is intended to be performed automatically under visual guidance using dedicated robotic manipulators. The present design intent is for used fuel to be stored inside of containment for at least 6 months and then transferred to local dry wells for intermediate term, on-site storage. The mechanical and structural concept development effort has included an emphasis on transportation and constructability to minimize construction costs and schedule. The design intent is that all components be factory fabricated into rail transportable modules that are assembled into subsystems at an on-site workshop prior to being lifted into position using a heavy-lift crane in an open-top style construction. While detailed accident identification and response sequence analysis has yet to be performed, the design concept incorporates multiple levels of radioactive material containment including fully passive responses to all identified design basis or non-very-low frequency beyond design basis accidents. Key building design elements include: 1) below grade siting to minimize vulnerability to aircraft impact, 2) multiple natural circulation decay heat rejection chimneys, 3) seismic base isolation, and 4) decay heat powered back-up electricity generation. The report provides a preconceptual design of the manipulators, the fuel transfer system, and the salt transfer loops. The mechanical handling of the fuel and how it is accomplished without instrumentation inside the salt is described within the report. All drives for the manipulators reside outside the reactor top flange. The design has also taken into account the transportability of major components and how they will be assembled on sit
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