5,548 research outputs found

    Hidden Extra U(1) at the Electroweak/TeV Scale

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    We propose a simple extension of the Standard Model (SM) by adding an extra U(1) symmetry which is hidden from the SM sector. Such a hidden U(1) has not been considered before, and its existence at the TeV scale can be explored at the LHC. This hidden U(1) does not couple directly to the SM particles, and couples only to new SU(2)_L singlet exotic quarks and singlet Higgs bosons, and is broken at the TeV scale. The dominant signals at the high energy hadron colliders are multi lepton and multi b-jet final states with or without missing energy. We calculate the signal rates as well as the corresponding Standard Model background for these final states. A very distinctive signal is 6 high p_T b-jets in the final state with no missing energy. For a wide range of the exotic quarks masses the signals are observable above the background at the LHC.Comment: 19 pages, 5 figure

    An Outbreak of Malaria in a Surgical Ward : Possibility of Mechanical Transmission

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    Penularan malaria pada umumnya terjadi melalui vektor yakni nyamuk Anopheles. Cara penularan lain adalah melalui transfusi darah atau secara congenital pada bayi yang baru lahir. Penularan secara me­kanis misalnya melalui alat suntik sangat jarang dijumpai. Berikut ini disajikan laporan penelitian terhadap 26 penderita malaria Plasmodium falciparum yang terjadi antara periode November 1981 sampai dengan Maret 1982 di bangsal bedah pria Rumah Sa­kit Umum Hasan Sadikin, Bandung. Hipotesa penularan melalui alat suntik/semprit ditegakkan sesudah diadakan penyelidikan epidemiologik dan entomologik. Ternyata disposable syringe di bangsal perawat­an tersebut digunakan untuk lebih dari satu penderita. Hipotesa diperkuat dengan tidak timbulnya lagi penderita setelah alat suntik hanya dipergunakan untuk satu orang penderita yang dirawat

    A Note on the Elementary Theory of Thermal Diffusion

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    A comparative study of a bio fuel cell with two different proton exchange membrane for the production of electricity from waste water

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    In the present study, electricity generation with waste water as substrate was investigated in a two compartment biofuel cell with two different combinations of electrodes and membrane. Two proton exchange membranes namely nafion and agar salt bridge and aluminum as electrode were used in the biofuel cell. It was found that biofuel cells operated with nafion produce maximum voltage 0.504 V with a current density of 0.1 A/m2 whereas in case of agar salt bridge maximum voltage of 0.145 V with a current density of 0.05 A/m2 was obtained. The more voltage produced in case of nafion is attributed to its low resistance for hydrogen ion transport

    Removal of hexavalent chromium Cr (VI) using activated carbon prepared from mango kernel activated with H3PO4

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    The present work reported the adsorption of Cr (VI) from aqueous solutions on activated carbon prepared from mango kernel, a seasonal waste from mango fruits. Kernels from dried mango fruit shells were taken out and pulverized in a micro-pulverizing mill. The powder thus obtained was activated with 40% H3PO4 and carbonized at 600 °C for 1 hour in an inert atmosphere. Physico-chemical characteristics such as elemental composition, surface area, functional groups and surface morphology of the activated carbon were analyzed using elemental analyzer, BET surface area analyzer, FTIR spectroscopy and SEM analysis respectively. Batch adsorption experiments were performed to investigate the effects of Cr (VI) concentration, carbon dose, pH, rate of agitation, time and temperature. The maximum adsorption capacity of Cr(VI) was found to be 7.8 mg g−1 at pH 2 and temperature 35 °C. The Langmuir adsorption isotherm best represented the equilibrium data and a pseudo-second order relation represented the adsorption kinetics
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