3,235 research outputs found
Gluino Stransverse Mass
We introduce a new observable, 'gluino stransverse mass', which is an
application of the Cambridge variable to the process where gluinos are
pair produced in proton-proton collision and each gluino subsequently decays
into two quarks and one LSP, $i.e. \tilde{g}\tilde{g} \to qq\tilde\chi_1^0\
qq\tilde\chi_1^0$. We show that the gluino stransverse mass can be utilized to
measure the gluino and the lightest neutralino masses separately, and also the
(1st and 2nd generation) squark masses if lighter than the gluino mass, thereby
providing a good first look at the pattern of sparticle masses experimentally.Comment: Typos corrected, Some discussions and one reference adde
M_T2-assisted on-shell reconstruction of missing momenta and its application to spin measurement at the LHC
We propose a scheme to assign a 4-momentum to each WIMP in new physics event
producing a pair of mother particles each of which decays to an invisible
weakly interacting massive particle (WIMP) plus some visible particle(s). The
transverse components are given by the value that determines the event variable
M_T2, while the longitudinal component is determined by the on-shell condition
on the mother particle. Although it does not give the true WIMP momentum in
general, this M_T2-assisted on-shell reconstruction of missing momenta provides
kinematic variables well correlated to the true WIMP momentum, and thus can be
useful for an experimental determination of new particle properties. We apply
this scheme to some processes to measure the mother particle spin, and find
that spin determination is possible even without a good knowledge of the new
particle masses.Comment: 11 pages, 10 figures, typos are corrected, figures are replace
Multi-frequency based location search algorithm of small electromagnetic inhomogeneities embedded in two-layered medium
In this paper, we consider a problem for finding the locations of
electromagnetic inhomogeneities completely embedded in homogeneous two layered
medium. For this purpose, we present a filter function operated at several
frequencies and design an algorithm for finding the locations of such
inhomogeneities. It is based on the fact that the collected Multi-Static
Response (MSR) matrix can be modeled via a rigorous asymptotic expansion
formula of the scattering amplitude due to the presence of such
inhomogeneities. In order to show the effectiveness, we compare the proposed
algorithm with traditional MUltiple SIgnal Classification (MUSIC) algorithm and
Kirchhoff migration. Various numerical results demonstrate that the proposed
algorithm is robust with respect to random noise and yields more accurate
location than the MUSIC algorithm and Kirchhoff migration.Comment: 21 pages, 25 figure
A Study of Pyrolysis of Charring Materials and its Application to Fire Safety and Biomass Utilization.
A theoretical and experimental study of pyrolysis of charring material applicable to fire safety and biomass utilization is presented in this thesis. This work is divided into three parts.
In the first part, thermal decomposition and pressure generation in charring solids undergoing opposed-flow flame spread is numerically studied with a detailed physics-based model. The result indicates that the char density and product yields are functions of depth due to an insulating char layer. The characteristics of various simplifying model assumptions such as global reaction, infinite rate kinetics and no convective gas transport were examined.
In the second part, a method of determining the pyrolysis temperature by enforcing mass and energy balance is proposed and validated by comparison with the decomposition kinetics model and the experiments. This pyrolysis temperature has the form of pyrolysis rate weighted average temperature for the entire charring process. Heat flux, sample size, heat of pyrolysis and kinetic parameters are the most important for determining an appropriate pyrolysis temperature. A non-dimensional correlation to determine an appropriate T_p was proposed. Excellent agreement between the pyrolysis front model using the correlation and experimental data of wood cylinder pyrolysis was achieved.
Finally, pyrolysis of wood sphere is studied both experimentally and theoretically. Weight loss and temperatures of the sample were measured during the experiments. Center temperature showed two distinct thermal behaviors with endothermic and exothermic reactions. The numerical study revealed the following findings: (i) Contribution of secondary tar decomposition and lignin decomposition to the temperature peak are small. (ii) Exothermic intermediate solid decomposition is responsible for the temperature peak. (iii) The temperature plateau is caused by endothermic cellulose decomposition. Based on the experimental and numerical results, a novel wood pyrolysis model is proposed. The model consists of three endothermic parallel reactions producing tar, gas and intermediate solid, followed by exothermic intermediate solid conversion to char and exothermic tar decomposition to char and gas.
A three-dimensional pyrolysis model for arbitrary geometry charring material was developed using front tracking method. The model was applied for wood sphere pyrolysis analysis and validated by comparison with the one-dimensional model.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/60757/1/wochpark_1.pd
Measuring the top quark mass with m_T2 at the LHC
We investigate the possibility to measure the top quark mass using the
collider variable at the LHC experiment. Monte Carlo studies of
are performed with the events corresponding to the dilepton decays of
produced at the LHC with 10 integrated luminosity. Our
analysis suggests that the top quark mass can be determined by the
variable alone with a good precision at the level of 1 GeV.Comment: 10 pages, 4 figure
Malignancies in Korean Patients with Inflammatory Myopathy
The aim of this study was to assess the prevalence and the common type of malignancies in Korean patients with polymyositis (PM) and dermatomyositis (DM) and to evaluate the differences of clinical and laboratory findings between patients with malignancy and those without malignancy. Forty-one Korean patients, who were diagnosed as PM or DM, were enrolled in this study. They fulfilled the Bohan and Peter's criteria for a definite diagnosis of PM and DM. Patients with PM were 25 and those with DM were 16. Eleven out of 41 patients (26.8%) had malignancies. The malignancy was diagnosed simultaneously or later in 81.8% of patients with inflammatory myopathy (IM). The breast cancer was the most common malignancy. In this study, forty three years old as a screening age for malignancy had 88.9% sensitivity and 50.2% specificity. The serum levels of creatine kinase (CK) were significantly lower in patients with malignancy than those without malignancy
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