6,365 research outputs found

    Transverse energy analysis of Au+Au collisions at 7.7, 11.5, 19.6, 27, and 39 GeV through the use of identified particles spectra

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    This thesis presents an analysis of the transverse energy resulting from the collisions of gold nuclei at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory. The transverse momentum distributions available from the STAR detector corresponding to nine different centralities for eight different identified particles, π± [pions, anti-pions], K± [kaons, anti-kaons], Λ± [lambdas, anti-lambdas], p [protons], and p̅ [anti-protons], resulting from the collisions at five different center-of-mass energies per nucleon -- 7.7, 11.5, 19.6, 27, and 39 GeV -- are used in the calculations of the corresponding transverse energies. The results, when compared with the calorimetric transverse energy measurement from the PHENIX detector, show discrepancies of up to 2.83 σ [standard deviations]

    Global nonlinear optimization for the estimation of static shift and interpretation of 1-D magnetotelluric sounding data

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    In the presence of conducting inhomogeneities in near-surface structures, apparent resistivity data in magnetotelluric sounding can be severely distorted. This is due to electric fields generated from boundary charges on surficial inhomogeneities. Such distortion persists throughout the entire recording range and is known as static shift in magnetotellurics. Frequencyindependent static shifts manifest as vertical, parallel shifts that occur in plots of the dual logarithmic scale of apparent resistivity versus time period. The phase of magnetotelluric sounding data remains unaffected by the static shift and can be used to remove the static shift to some extent. However, individual inversion of phase data yields highly nonunique results, and alone it will not work to correctly remove the static shift. Inversions of uncorrected magnetotelluric data yield erroneous and unreliable estimations, while static-shift-corrected magnetotelluric data provide better and reliable estimations of the resistivities and thicknesses of subsurface structures. In the present study, static shift (a frequencyindependent real constant) is also considered as one of the model parameters and is optimized together with other model parameters(resistivity and thickness) using the very fast simulated annealing global inversion technique. This implies that model parameters are determined simultaneously with the estimate of the static shift in the data. Synthetic and noisy data generated for a number of models are interpreted, to demonstrate the efficacy of the approach to yield reliable estimates of subsurface structures when the apparent resistivity data are affected by static shift. Individual inversions of static-shift-affected apparent resistivity data and phase data yield unreliable estimations of the model parameters. Furthermore, the estimated model parameters after individual data inversions do not show any systematic correlations with the amount of static shift in the data. The present study shows that only joint inversion of the apparent resistivity and phase data, without or with optimizing of the static shift, yields models that show good fits between the observed and the model data. Joint inversion results also reveal a systematic relationship between the estimated model parameters and the static shift in the data. The proposed approach also shows that estimated resistivities are ‘S’ (the static shift parameter) times the actual resistivities, and that estimated thicknesses are √S times the actual thicknesses without optimization of the static shift. This result is in good agreement with the existing relationship in the literature. Therefore, the global optimization procedure developed can be effectively used to optimize the static shifts in data, to obtain reliable estimations of model parameters. Subsequently, joint inversion of the apparent resistivity and phase data, with optimization of the static shift, is performed, which yields accurate estimates of subsurface structures. It is demonstrated that this approach can also be used when the data is not affected by the static shift. In such cases, the estimated static shift parameter ‘S’ will be close to unity. The efficacy of the approach is demonstrated with a field example from Singhbhum craton, eastern India, by providing an accurate estimation of the craton thickness and the conducting structure that lies below the craton

    Architecture of Automated Database Tuning Using SGA Parameters

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    Business Data always growth from kilo byte, mega byte, giga byte, tera byte, peta byte, and so far. There is no way to avoid this increasing rate of data till business still running. Because of this issue, database tuning be critical part of a information system. Tuning a database in a cost-effective manner is a growing challenge. The total cost of ownership (TCO) of information technology needs to be significantly reduced by minimizing people costs. In fact, mistakes in operations and administration of information systems are the single most reasons for system outage and unacceptable performance [3]. One way of addressing the challenge of total cost of ownership is by making information systems more self-managing. A particularly difficult piece of the ambitious vision of making database systems self-managing is the automation of database performance tuning. In this paper, we will explain the progress made thus far on this important problem. Specifically, we will propose the architecture and Algorithm for this problem

    PL/SQL and Bind Variable: the two ways to increase the efficiency of Network Databases

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    Modern data analysis applications are driven by the Network databases. They are pushing traditional database and data warehousing technologies beyond their limits due to their massively increasing data volumes and demands for low latency. There are three major challenges in working with network databases: interoperability due to heterogeneous data repositories, proactively due to autonomy of data sources and high efficiency to meet the application demand. This paper provides the two ways to meet the third challenge of network databases. This goal can be achieved by network database administrator with the usage of PL/SQL blocks and bind variable. The paper will explain the effect of PL/SQL block and bind variable on Network database efficiency to meet the modern data analysis application demand

    A PROSPECTIVE COMPARATIVE STUDY ON LOCALLY ADVANCED RECTAL CARCINOMA TREATED WITH PRE-OPERATIVE SHORT-COURSE RADIOTHERAPY VERSUS LONG-COURSE RADIOTHERAPY WITH CONCOMITANT CHEMOTHERAPY

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    Objective: In locally advanced non-metastatic rectal carcinoma, pre-operative radiotherapy is an acceptable alternative over post-operative radiation to improve locoregional control after radical surgery. There are two regimens of pre-operative radiotherapy – short-course radiotherapy (25 Gy/5 fractions/1 week) and long-course chemoradiotherapy (CRT) (50.4 Gy/28 fractions/5.5 weeks). Our study aimed to compare the pathological response, margin negative surgery rates, and treatment-related acute toxicities between these two approaches. Methods: Patients with histologically proven locally advanced, non-metastatic rectal adenocarcinoma were randomized into study group and control group – the study group received short-course radiotherapy (25 Gy/5 fractions/1 week) followed by surgery after 7–10 days of completion of radiotherapy and the control group received long-course radiotherapy (50.4 Gy/28 fractions/5.5 weeks) with concurrent capecitabine followed by surgery after 4–6 weeks of completion of radiotherapy. Histopathology reports were studied in both groups for the determination of pathological response of tumor and surgical margin status. All patients received adjuvant chemotherapy for 6 months with oxaliplatin and capecitabine. For the assessment of treatment-related acute toxicities, patients were examined during the entire course of treatment. Results: Overall pathological response (complete response+partial response) was 81.25% in the study arm and 86.66% in the control arm. Complete response rate was 15% in the study arm and 25% in the control arm. Margin negative surgery rates were higher in long-course CRT than short-course radiotherapy (90% vs. 82%), but it was statistically insignificant. Radiation-induced acute skin reactions (less than Grade 2) were significantly higher in long-course CRT arm (p=0.003). Conclusion: There is no significant difference between pre-operative short-course radiotherapy and long-course concomitant CRT in terms of efficacy and acute toxicity profile. Thus, with our limited resources and huge patient load, short-course radiotherapy can be used as an acceptable alternative to long-course CRT

    Numerical simulation of bubble growth in film boiling using a coupled level-set and volume-of-fluid method

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    A coupled level-set and volume-of-fluid method is presented for modeling incompressible two-phase flows with surface tension. The coupled algorithm conserves mass and captures the complicated interfaces very accurately. A planar simulation of bubble growth is performed in water at near critical pressure for different degrees of superheat. The effect of superheat on the frequency of bubble formation has been analyzed. In addition, simulation of film boiling and bubble formation is performed in refrigerant R134a at near critical and far critical pressures. The effect of saturation pressure on the frequency of bubble formation has also been studied. A deviation from the periodic bubble release is observed in the case of superheat beyond 15 K in water. The effect of heat flux on the instability has also been analyzed. It is found that for water at near critical condition, a decrease in superheat from 15 to 10 K leads to oscillations with subharmonics influencing the time period of the ebullition cycle

    Produção, estudo e caracterização de biocombustíveis a partir de macroalgas (Azolla pinnata)

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    The demands for energy and the scarcity in fossil fuel are constantly increasing. This has resulted in the search for sustainable, renewable, and low cost biofuel that has triggered the search for potential bioenergy crops. Aquatic plants that can grow rapidly with minimum resources and can produce biomass in bulk amounts are driving the attention of scientists and researchers throughout the world. The production of biofuels from such organic materials and waste components can result in developing of sustainable alternative that will not only be beneficial to the environment but also to public health. In this study, one such aquatic macro algae Azolla pinnata proved to be potential source for biofuel production. The evaluation of its growth was done and trans-esterification of Azolla pinnata lipid was carried out to produce biofuel. The species have a unique combination of physical, chemical and nutrients composition that makes it a boon to mankind. This macro algae was subjected to series of laboratory testing and evaluation for its characterization such as acid value test, trans-esterification, fatty acid methyl esters (FAMEs) test, gas chromatography which showed the feasibility of algal based biofuel. The comparison of properties of extracted biofuel (physicochemical) from Azollla pinnta was done with standardized ASTM D6751 values. The outcome of produced biofuel was very close to conventional fuel.La demanda de energía y la escasez de combustibles fósiles aumentan constantemente. Esto resultó en la búsqueda de biocombustibles sostenibles, renovables y de bajo costo, lo que desencadenó la búsqueda de cultivos bioenergéticos potenciales. Las plantas acuáticas que pueden crecer rápidamente con recursos mínimos y pueden producir biomasa en grandes cantidades están atrayendo la atención de científicos e investigadores de todo el mundo. La producción de biocombustibles a partir de tales materiales orgánicos y componentes de desecho puede resultar en el desarrollo de alternativas sostenibles que serán beneficiosas no solo para el medio ambiente sino también para la salud pública. En este estudio, una de estas macroalgas acuáticas, Azolla pinnata, demostró ser una fuente potencial para la producción de biocombustibles. Se realizó la evaluación de su crecimiento y se realizó la transesterificación del lípido Azolla pinnata para la producción de biocombustible. Las especies tienen una combinación única de composición física, química y de nutrientes que las hace beneficiosas para la humanidad. Esta macroalga fue sometida a una serie de pruebas y evaluaciones de laboratorio para su caracterización, como prueba de índice de acidez, transesterificación, prueba de ésteres metílicos de ácidos grasos (FAMEs), cromatografía de gases que mostró la viabilidad del biocombustible a base de algas. La comparación de las propiedades del biocombustible extraído (físico-químico) de Azollla pinnta se realizó con valores estandarizados de la norma ASTM D6751. El resultado del biocombustible producido fue muy cercano al del combustible convencional.As demandas por energia e a escassez de combustível fóssil estão aumentando constantemente. Isso resultou na busca por biocombustíveis sustentáveis, renováveis e de baixo custo, o que desencadeou a busca por potenciais cultivos bioenergéticos. Plantas aquáticas que podem crescer rapidamente com recursos mínimos e podem produzir biomassa em grandes quantidades estão atraindo a atenção de cientistas e pesquisadores em todo o mundo. A produção de biocombustíveis a partir de tais materiais orgânicos e componentes de resíduos pode resultar no desenvolvimento de alternativas sustentáveis que serão benéficas não apenas para o meio ambiente, mas também para a saúde pública. Neste estudo, uma dessas macroalgas aquáticas Azolla pinnata provou ser uma fonte potencial para a produção de biocombustíveis. A avaliação de seu crescimento foi feita e a transesterificação do lipídio Azolla pinnata foi realizada para a produção de biocombustível. As espécies têm uma combinação única de composição física, química e de nutrientes que a torna um benefício para a humanidade. Esta macroalga foi submetida a uma série de testes laboratoriais e avaliações para sua caracterização, como teste de valor ácido, transesterificação, teste de ésteres metílicos de ácidos graxos (FAMEs), cromatografia gasosa que mostrou a viabilidade de biocombustível à base de algas. A comparação das propriedades do biocombustível extraído (físico-químico) de Azollla pinnta foi feita com valores padronizados ASTM D6751. O resultado do biocombustível produzido foi muito próximo ao do combustível convencional

    Shared-Constraint Range Reporting

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    Orthogonal range reporting is one of the classic and most fundamental data structure problems. (2,1,1) query is a 3 dimensional query with two-sided constraint on the first dimension and one sided constraint on each of the 2nd and 3rd dimension. Given a set of N points in three dimension, a particular formulation of such a (2,1,1) query (known as four-sided range reporting in three-dimension) asks to report all those K points within a query region [a, b]X(-infinity, c]X[d, infinity). These queries have overall 4 constraints. In Word-RAM model, the best known structure capable of answering such queries with optimal query time takes O(N log^{epsilon} N) space, where epsilon>0 is any positive constant. It has been shown that any external memory structure in optimal I/Os must use Omega(N log N/ log log_B N) space (in words), where B is the block size [Arge et al., PODS 1999]. In this paper, we study a special type of (2,1,1) queries, where the query parameters a and c are the same i.e., a=c. Even though the query is still four-sided, the number of independent constraints is only three. In other words, one constraint is shared. We call this as a Shared-Constraint Range Reporting (SCRR) problem. We study this problem in both internal as well as external memory models. In RAM model where coordinates can only be compared, we achieve linear-space and O(log N+K) query time solution, matching the best-known three dimensional dominance query bound. Whereas in external memory, we present a linear space structure with O(log_B N + log log N + K/B) query I/Os. We also present an I/O-optimal (i.e., O(log_B N+K/B) I/Os) data structure which occupies O(N log log N)-word space. We achieve these results by employing a novel divide and conquer approach. SCRR finds application in database queries containing sharing among the constraints. We also show that SCRR queries naturally arise in many well known problems such as top-k color reporting, range skyline reporting and ranked document retrieval
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