1,873 research outputs found

    Surface Oxide Formation during Rapid Heating of Zn-coated Press Hardening Steel

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    During the conventional die-quenching processing of a galvanized PHS steel, a thick ZnO layer is formed at the surface. When the heating rate is increased, the oxide at the surface is a thin Al2O3 layer. This remarkable change in surface oxide during rapid heating is due to the partial melting of the coating instead of the solidification of the coating and the formation of Fe-Zn intermetallics. In the present study, the characterization of the surface oxide formation at different heating rates is presented.X1184Ysciescopu

    The stransverse mass, MT2, in special cases

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    This document describes some special cases in which the stransverse mass, MT2, may be calculated by non-iterative algorithms. The most notable special case is that in which the visible particles and the hypothesised invisible particles are massless -- a situation relevant to its current usage in the Large Hadron Collider as a discovery variable, and a situation for which no analytic answer was previously known. We also derive an expression for MT2 in another set of new (though arguably less interesting) special cases in which the missing transverse momentum must point parallel or anti parallel to the visible momentum sum. In addition, we find new derivations for already known MT2 solutions in a manner that maintains manifest contralinear boost invariance throughout, providing new insights into old results. Along the way, we stumble across some unexpected results and make conjectures relating to geometric forms of M_eff and H_T and their relationship to MT2.Comment: 11 pages, no figures. v2 corrects minor typos. v3 corrects an incorrect statement in footnote 8 and inserts a missing term in eq (3.9). v4 and v5 correct minor typos spotted by reader

    Supersymmetric particle mass measurement with the boost-corrected contransverse mass

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    A modification to the contransverse mass (MCT) technique for measuring the masses of pair-produced semi-invisibly decaying heavy particles is proposed in which MCT is corrected for non-zero boosts of the centre-of-momentum (CoM) frame of the heavy states in the laboratory transverse plane. Lack of knowledge of the mass of the CoM frame prevents exact correction for this boost, however it is shown that a conservative correction can nevertheless be derived which always generates an MCT value which is less than or equal to the true value of MCT in the CoM frame. The new technique is demonstrated with case studies of mass measurement with fully leptonic ttbar events and with SUSY events possessing a similar final state.Comment: 33 pages, 33 .eps figures, JHEP3 styl

    Application of Quenching and Partitioning Processing to Medium Mn Steel

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    The present work analyzes the application of quenching and partitioning processing to medium Mn steel to obtain a new type of ultra-high-strength multiphase medium Mn steel. The selection of the quench temperature makes it possible to vary the ultimate tensile strength within a range of 500 MPa. The processing leads to low-carbon lath martensite matrix with a controlled volume fraction of retained austenite.open112731sciescopu

    Spin Discrimination in Three-Body Decays

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    The identification of the correct model for physics beyond the Standard Model requires the determination of the spin of new particles. We investigate to which extent the spin of a new particle XX can be identified in scenarios where it decays dominantly in three-body decays XffˉYX\to f\bar{f} Y. Here we assume that YY is a candidate for dark matter and escapes direct detection at a high energy collider such as the LHC. We show that in the case that all intermediate particles are heavy, one can get information on the spins of XX and YY at the LHC by exploiting the invariant mass distribution of the two standard model fermions. We develop a model-independent strategy to determine the spins without prior knowledge of the unknown couplings and test it in a series of Monte Carlo studies.Comment: 31+1 pages, 4 figures, 8 tables, JHEP.cls include

    Biomedical Scientists' Perceptions of Ethical and Social Implications: Is There a Role for Research Ethics Consultation?

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    Research ethics consultation programs are being established with a goal of addressing the ethical, societal, and policy considerations associated with biomedical research. A number of these programs are modelled after clinical ethics consultation services that began to be institutionalized in the 1980s. Our objective was to determine biomedical science researchers' perceived need for and utility of research ethics consultation, through examination of their perceptions of whether they and their institutions faced ethical, social or policy issues (outside those mandated by regulation) and examination of willingness to seek advice in addressing these issues. We conducted telephone interviews and focus groups in 2006 with researchers from Stanford University and a mailed survey in December 2006 to 7 research universities in the U.S.A total of 16 researchers were interviewed (75% response rate), 29 participated in focus groups, and 856 responded to the survey (50% response rate). Approximately half of researchers surveyed (51%) reported that they would find a research ethics consultation service at their institution moderately, very or extremely useful, while over a third (36%) reported that such a service would be useful to them personally. Respondents conducting human subjects research were more likely to find such a service very to extremely useful to them personally than respondents not conducting human subjects research (20% vs 10%; chi(2) p<0.001).Our findings indicate that biomedical researchers do encounter and anticipate encountering ethical and societal questions and concerns and a substantial proportion, especially clinical researchers, would likely use a consultation service if they were aware of it. These findings provide data to inform the development of such consultation programs in general

    Congenital absence of inferior vena cava and thrombosis: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>A congenitally absent Inferior Vena Cava (IVC) is a rare anomaly that is recognised to be associated with idiopathic Deep Venous Thrombosis (DVT), particularly in the young. It may not be apparent until later in life. Retrospectively, as discussed in this case, there can be clues indicating the presence of such an anomaly from a young age. However, it is not clear whether early recognition of this condition would affect the prognosis and treatment.</p> <p>Case presentation</p> <p>A 54 year old gentleman was admitted with 3 weeks of abdominal pain and localised swelling over the right flank. Examination revealed palpable 'snake-like' tortuous, tender lumps on the abdominal wall. Past history revealed chronic non-healing venous leg ulcers, and varicose veins necessitating varicose vein ligation at a very young age. The ulcers eventually needed skin grafting.</p> <p>During this, current admission he was investigated and diagnosed with Deep Vein Thrombosis (DVT). CT scan, performed to search for intra-abdominal cancer, revealed absence of the Inferior Vena Cava with extensive thrombosed collaterals of the superficial abdominal and azygous veins and a congenitally atrophic left kidney.</p> <p>Conclusion</p> <p>This is a case of one of the oldest patient described in the literature to be diagnosed with absence of the IVC. It is thought that IVC anomalies are under-diagnosed, and may be commoner than once believed. However there were vital clues in his previous medical history suspicious for an underlying venous anomaly. Idiopathic DVT in a relatively young person with a past history of chronic leg ulceration or varicose veins should be investigated for congenital anomalies of the IVC. This is best achieved by CT scan of the abdomen.</p

    Measuring Invisible Particle Masses Using a Single Short Decay Chain

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    We consider the mass measurement at hadron colliders for a decay chain of two steps, which ends with a missing particle. Such a topology appears as a subprocess of signal events of many new physics models which contain a dark matter candidate. From the two visible particles coming from the decay chain, only one invariant mass combination can be formed and hence it is na\"ively expected that the masses of the three invisible particles in the decay chain cannot be determined from a single end point of the invariant mass distribution. We show that the event distribution in the log(E1T/E2T)\log(E_{1T}/E_{2T}) vs. invariant mass-squared plane, where E1TE_{1T}, E2TE_{2T} are the transverse energies of the two visible particles, contains the information of all three invisible particle masses and allows them to be extracted individually. The experimental smearing and combinatorial issues pose challenges to the mass measurements. However, in many cases the three invisible particle masses in the decay chain can be determined with reasonable accuracies.Comment: 45 pages, 32 figure

    Kahler Independence of the G2-MSSM

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    The G2-MSSM is a model of particle physics coupled to moduli fields with interesting phenomenology both for colliders and astrophysical experiments. In this paper we consider a more general model - whose moduli Kahler potential is a completely arbitrary G2-holonomy Kahler potential and whose matter Kahler potential is also more general. We prove that the vacuum structure and spectrum of BSM particles is largely unchanged in this much more general class of theories. In particular, gaugino masses are still supressed relative to the gravitino mass and moduli masses. We also consider the effects of higher order corrections to the matter Kahler potential and find a connection between the nature of the LSP and flavor effects.Comment: Final version, matches the version published in JHE
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