101 research outputs found

    Methods of measuring residual stresses in components

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    Residual stresses occur in many manufactured structures and components. Large number of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these components. Over the years, different methods have been developed to measure residual stress for different types of components in order to obtain reliable assessment. The various specific methods have evolved over several decades and their practical applications have greatly benefited from the development of complementary technologies, notably in material cutting, full-field deformation measurement techniques, numerical methods and computing power. These complementary technologies have stimulated advances not only in measurement accuracy and reliability, but also in range of application; much greater detail in residual stresses measurement is now available. This paper aims to classify the different residual stresses measurement methods and to provide an overview of some of the recent advances in this area to help researchers on selecting their techniques among destructive, semi destructive and non destructive techniques depends on their application and the availabilities of those techniques. For each method scope, physical limitation, advantages and disadvantages are summarized. In the end this paper indicates some promising directions for future developments

    Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment

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    In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved

    Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target

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    The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011 muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27±0.07) × 1011 protons on target was recorded. This amounts to approximatively 1% of a SHiP spill

    The Methodological Development of the Confucian Philosophy in the Pre-Chin Period

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    TesisEsta tesis estudia la relación entre desgaste de mantos y parámetros críticos de funcionamiento del chancador primario marca Traylor, tipo o modelo NT (60”x113”) de la Minera Chinalco Perú. Los mantos son forros internos del chancador que se desgastan con frecuencia debido a la capacidad de producción de 120 000 toneladas de mineral por día; y poseen una vida útil normal de 6 meses o 4400 horas. En el estudio, se aplicó la siguiente metodología: Método de matematización, tipo de investigación básica, nivel de investigación descriptivo y diseño descriptivo simple. La secuencia para realizar la investigación fue la siguiente: 1) Listado de principales parámetros de funcionamiento. 2) Análisis de criticidad de parámetros donde se encontró que la velocidad angular del eje principal, temperatura de los mantos, dureza del mineral ingresado y la eficiencia del chancador; son los parámetros críticos. 3) Toma de datos de los parámetros críticos. 4) Planteamiento de hipótesis alternas e hipótesis nulas. 5) Proceso estadístico para encontrar la relación entre el desgaste de mantos y los parámetros críticos calculando la correlación de Pearson (“rxy”), y la “t” de Student para determinar la significación de la correlación. Para la correlación de Pearson (“rxy”) se encontraron los siguientes resultados: “rxy” desgaste del manto vs velocidad angular del eje principal 0.998. Desgaste del manto vs temperatura de los mantos 0.999. Desgaste del manto vs dureza del mineral ingresado 0.999 y desgaste vs eficiencia del chancador 0.998. Para determinar la significación de la correlación mediante la prueba “t” de Student se encontró lo siguiente: “t” calculado para desgaste del manto vs velocidad angular del eje principal 74.05. Desgaste del manto vs temperatura de los mantos 104.81. Desgaste del manto vs dureza del mineral ingresado 104.81 y desgaste del manto vs eficiencia del chancador 74.05. “t” de Student por tabla para los cuatro parámetros críticos 1.72. Como la “t” se Student calculado resultó mayor que la “t” de Student por tabla se rechaza las hipótesis nulas y se validan las hipótesis alternas. Por tanto, existe alta relación entre los parámetros críticos y el desgaste de mantos

    The Problem of Rhizomata in the Pre-socratic Period

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    Unlike the problems of Arche the Pre-socratic philosophers discussed the elements of the material world in the rhizomata questions. This article is divided into three main parts. The first part deals with the historical development of the problems of rhizomata proceeding in the order of pluralism, mechanism and teleology. In the second part we investigate the essential contents of rhizomata operating from Empedocles, Democritus and Anaxagoras. The causal principle took place in the transcendental and immanental sophistication, and at the same time the materialistic and the idealistic Weltanschauung have had their origin and their na?ve forms. Finally, in the third part, the contemporary significance is discussed in the light of Aristotle’s metaphysical point of view. The author tries here to raise some questions about the foundations of the oppositional atmosphere of the Materialism and the Idealism today, which seems to have their origin from the Pre-socratic period

    西漢社會哲學之研究

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