1,824 research outputs found

    Characterization 410 Stainless Steel by Vacuum Tempering Process

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    It has been reported that low-temperature vacuum tempering of 410 stainless steel hard layer improving wear resistance and hardness. Grade 410 stainless steel being a hardened material were modified by low temperature tempering process. By the process of tempering, brittleness on the stainless steel material will be reduced and ductility will be promoted. The microstructure, surface hardness and erosion-corrosion resistance were systematically evaluated. Vacuum tempering is done at low temperature of 430℃ can form a hardened layer, and with the treated time prolong, the thickness of the layer increased. The stainless specimens were vacuum tempered for 30 minutes, 60 minutes and 120 minutes. Wear tests were conducted with the help of pin on disc apparatus. The output results were determined with various metallographic tests like scanning electron microscope and optical microscope results

    The Stability of the Gauge Hierarchy in SU(5)×SU(5)SU(5) \times SU(5)

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    It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for doublet-triplet splitting can be implemented in SU(5)×SU(5)SU(5) \times SU(5) models, which requires no adjoint Higgs fields. This is an advantage from the point of view of string theory construction. Here the stability of the gauge hierarchy is examined in detail, and it is shown that it can be guaranteed much more simply than in SO(10)SO(10). In fact a Z2Z_2 symmetry ensures the stability of the DW form of the expectation values to all orders in GUT-scale VEVs. It is also shown that models based on SO(10)×SU(5)SO(10) \times SU(5) have the advantages of SU(5)×SU(5)SU(5) \times SU(5) while permitting complete quark-lepton unification as in SO(10)SO(10).Comment: 13 pages, LaTe

    Constraining Proton Lifetime in SO(10) with Stabilized Doublet-Triplet Splitting

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    We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos--Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The \mu term of order TeV is found to be naturally induced. A Z_2-assisted anomalous U(1)_A gauge symmetry plays a crucial role in achieving these results. The threshold corrections to alpha_3(M_Z), somewhat surprisingly, are found to be controlled by only a few effective parameters. This leads to a very predictive scenario for proton decay. As a novel feature, we find an interesting correlation between the d=6 (p\to e^+\pi^0) and d=5 (p\to \nu-bar K+) decay amplitudes which allows us to derive a constrained upper limit on the inverse rate of the e^+\pi^0 mode. Our results show that both modes should be observed with an improvement in the current sensitivity by about a factor of five to ten.Comment: 21 pages LaTeX, 2 figures, Few explanatory sentences and three new references added, minor typos corrected

    Bflier's: A Novel Butterfly Inspired Multi-robotic Model in Search of Signal Sources

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    The diversified ecology in nature had various forms of swarm behaviors in many species. The butterfly species is one of the prominent and a bit insightful in their random flights and converting that into an artificial metaphor would lead to enormous possibilities. This paper considers one such metaphor known as Butterfly Mating Optimization (BMO). In BMO, the Bfly follows the patrolling mating phenomena and simultaneously captures all the local optima of multimodal functions. To imitate this algorithm, a mobile robot (Bflybot) was designed to meet the features of the Bfly in the BMO algorithm. Also, the multi-Bflybot swarm is designed to act like butterflies in nature and follow the algorithm's rules. The real-time experiments were performed on the BMO algorithm in the multi-robotic arena and considered the signal source as the light source. The experimental results show that the BMO algorithm is applicable to detect multiple signal sources with significant variations in their movements i.e., static and dynamic. In the case of static signal sources, with varying initial locations of Bflybots, the convergence is affected in terms of time and smoothness. Whereas the experiments with varying step-size leads to their variation in the execution time and speed of the bots. In this work, experiments were performed in a dynamic environment where the movement of the signal source in both maneuvering and non-maneuvering scenarios. The Bflybot swarm is able to detect the single and multi-signal sources, moving linearly in between two fixed points, in circular, up and down movements.To evaluate the BMO phenomenon, various ongoing and prospective works such as mid-sea ship detection, aerial search applications, and earthquake prediction were discussed.Comment: 12 pages, 17 figure

    SU(16) grandunification: breaking scales, proton decay and neutrino magnetic moment

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    We give a detailed renormalization group analysis for the SU(16) grandunified group with general breaking chains in which quarks and leptons transform separately at intermediate energies. Our analysis includes the effects of Higgs bosons. We show that the grandunification scale could be as low as 108.5\sim 10^{8.5} GeV and give examples where new physics could exist at relatively low energy (250\sim 250 GeV). We consider proton decay in this model and show that it is consistent with a low grandunification scale. We also discuss the possible generation of a neutrino magnetic moment in the range of 101110^{-11} to 1010μB10^{-10}\mu_B with a very small mass by the breaking of the embedded SU(2)ν_\nu symmetry at a low energy.Comment: (16 pages in REVTEX + 6 figures not included) OITS-49

    Primary Adenosquamous Carcinoma of Ascending Colon – A Rare Entity

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    Colorectal cancers (CRC) are on the rise globally with increased incidence rate 5.7/100000 cases in developing countries like India. 1 Majority (90%) of CRC are adenocarcinoma. The primary adenosquamous carcinoma (ASC) of the colon is exceedingly rare variant of adenocarcinoma with incidence of 0.025% and accounts for 0.1% of colonic epithelial malignancies. 2 The squamous differentiation accounts for its aggressiveness and poor prognosis. Here we report a rare case of primary ASC in 80year old male who presented with large bowel obstruction and peritonitis. A 80-year-old male brought to causality with history of fever, vomiting, pain in abdomen, altered sensorium since three days. The clinical examination revealed intestinal obstruction and peritonitis. Patient was immediately subjected for radiological and hematology investigations which showed signs of bowel obstruction and perforation. On emergency exploratory laparotomy, colonic perforation was identified along with an ulcer proliferative mass in ascending colon. Gross examination of right hemicolectomy revealed 9x6x3cm ulcero proliferative mass in ascending colon. The microscopic examination showed an infiltrating tumor composed of adenocarcinoma component and areas of squamous differentiation (60%) noted. Tumor was invading through muscularis propria and serosa. Final diagnosis of primary ASC was made. Colonic ASC is rare and associated with poorer prognosis. The squamous cell differentiation has greater metastatic potential than adenocarcinoma. Compared to adenocarcinoma, ASC is more likely to manifest with advanced disease and complications. Keywords: Adenosquamous, Carcinoma, Colo

    Supersymmetric SO(10) Simplified

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    In the context of supersymmetric SO(10)SO(10) grand unified models, it is shown that the gauge symmetry breaking as well as a natural doublet--triplet splitting can be achieved with a minimal Higgs system consisting of a single adjoint and a pair of vector and spinor multiplets. Such a Higgs spectrum has been shown to arise in the free fermionic formulation of superstrings. Since the symmetry breaking mechanism relies on non--renormalizable operators, some of the Higgs particles of the model turn out to have masses somewhat below the GUT scale. As a consequence, the unification scale is raised to about 2×1017 GeV2 \times 10^{17}~GeV and sin2θW^2\theta_W is predicted to be slightly larger than the minimal SUSY--SU(5)SU(5) value. Including threshold uncertainties, which turn out to be surprisingly small in the model, we show that sin2θW^2\theta_W prediction is consistent with experiments.Comment: 23 pages, BA-94-4

    b-physics signals of the lightest CP-odd Higgs in the NMSSM at large tan beta

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    We investigate the low energy phenomenology of the lighter pseudoscalar A10A_1^0 in the NMSSM. The A10A_1^0 mass can naturally be small due to a global U(1)RU(1)_R symmetry of the Higgs potential, which is only broken by trilinear soft terms. The A10A_1^0 mass is further protected from renormalization group effects in the large tanβ\tan \beta limit. We calculate the bsA10b \to s A_1^0 amplitude at leading order in tanβ\tan \beta and work out the contributions to rare KK, BB and radiative Υ\Upsilon-decays and BBˉB -\bar B mixing. We obtain constraints on the A10A_1^0 mass and couplings and show that masses down to O(10){\cal{O}}(10) MeV are allowed. The bb-physics phenomenology of the NMSSM differs from the MSSM in the appearance of sizeable renormalization effects from neutral Higgses to the photon and gluon dipole operators and the breakdown of the MSSM correlation between the Bsμ+μB_s \to \mu^+ \mu^- branching ratio and BsBˉsB_s - \bar B_s mixing. For A10A_1^0 masses above the tau threshold the A10A_1^0 can be searched for in bsτ+τb \to s \tau^+ \tau^- processes with branching ratios \lsim 10^{-3}.Comment: 18 pages, 3 figures; references adde
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