587 research outputs found

    Dark matter and stable bound states of primordial black holes

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    We present three reasons for the formation of gravitational bound states of primordial black holes,called holeums,in the early universe.Using Newtonian gravity and nonrelativistic quantum mechanics we find a purely quantum mechanical mass-dependant exclusion property for the nonoverlap of the constituent black holes in a holeum.This ensures that the holeum occupies space just like ordinary matter.A holeum emits only gravitational radiation whose spectrum is an exact analogue of that of a hydrogen atom. A part of this spectrum lies in the region accessible to the detectors being built.The holeums would form haloes around the galaxies and would be an important component of the dark matter in the universe today.They may also be the constituents of the invisible domain walls in the universe.Comment: 13 pages,2tables,for wider circulation,PD

    Development and evaluation of plastic based solar still for production of distilled water

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    Solar still was developed and evaluated at Department of Renewable Energy Engineering, College of Agricultural Engineering and Technology, Dediapada. The average yield of distilled water in developed solar still varied from 1055-1498 ml/m 2 -day during winter and summer where as in already developed still varied 1350 to 1550 ml /m 2 day . Thermal efficiency of developed solar still was found as 20 per cent .The physicochemical analysis was carried out to examine the effect of distillation on tap water. A drastic reduction in the TDS, Chlorides, Calcium hardness and magnesium hardness, dissolved silica was observed through solar distillation. The payback period of the unit was only 6 months and after that period the unit produced net profit. The manufacturing cost of this developed solar still was only Rs. 1640/- which was totally manufactured in plastic material so no any corrosive material came in contact for changing the property of distilled water as output. Cleaning of solar still could be easily carried out by just removing the w shape dome of developed device which cannot be possible in available solar still in market

    Design, development and demonstration of a Shallow solar tunnel dryer for non-electrified areas

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    This paper presents the design, construction and performance evaluation of a shallow solar tunnel dryer for agro and industrial products. In the shallow solar tunnel dryer, there are three separate units viz.: an air heating unit, drying unit and air diversion unit. Total area of the solar tunnel dryer was 21 m². The heated air from a separate solar air heating zone is passed through a product bed, and at the same time, the drying tunnel bed absorbs solar energy directly through the transparent UV stabilized plastic sheet used as covering material. This dryer was not required any external sources of the power to operate the electrical fan. The system was designed to operate at a temperature of 50 to 60oC. The system was installed at the institute and initial testing was conducted. After that the system was also demonstrated at the actual potential user’s site. The results obtained during the test period revealed that the temperatures inside the tunnel drying zone and solar air heating zone were much higher than the ambient air temperature during most hours of the day-light. The temperature rise inside the drying tunnel was up to 67.4°C at peak hour’s period (noon). The drying rat e and thermal efficiency of the collector were 1.73 kg/h and 26.0% respectively. The high outlet temperature indicated the scope of loading the dryer further

    Random matrix ensemble with random two-body interactions in presence of a mean-field for spin one boson systems

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    For mm number of bosons, carrying spin (SS=1) degree of freedom, in Ω\Omega number of single particle orbitals, each triply degenerate, we introduce and analyze embedded Gaussian orthogonal ensemble of random matrices generated by random two-body interactions that are spin (S) scalar [BEGOE(2)-S1S1]. The embedding algebra is U(3)⊃G⊃G1⊗SO(3)U(3) \supset G \supset G1 \otimes SO(3) with SO(3) generating spin SS. A method for constructing the ensembles in fixed-(mm, SS) space has been developed. Numerical calculations show that the form of the fixed-(mm, SS) density of states is close to Gaussian and level fluctuations follow GOE. Propagation formulas for the fixed-(mm, SS) space energy centroids and spectral variances are derived for a general one plus two-body Hamiltonian preserving spin. In addition to these, we also introduce two different pairing symmetry algebras in the space defined by BEGOE(2)-S1S1 and the structure of ground states is studied for each paring symmetry.Comment: 22 pages, 6 figure

    Accelerator Magnet Development Based on COMB Technology with STAR Wires

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    This paper reports progress in the development of COMB magnet technology with STAR wires. A two-layer dipole magnet with 60 mm clear bore has been recently fabricated and tested in liquid nitrogen. The purpose of the test was to determine what kind of critical current degradation occurs in the process of winding the STAR wire into the COMB structure.Comment: CEC/ICMC2

    Very high frequency gravitational wave background in the universe

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    Astrophysical sources of high frequency gravitational radiation are considered in association with a new interest to very sensitive HFGW receivers required for the laboratory GW Hertz experiment. A special attention is paid to the phenomenon of primordial black holes evaporation. They act like black body to all kinds of radiation, including gravitons, and, therefore, emit an equilibrium spectrum of gravitons during its evaporation. Limit on the density of high frequency gravitons in the Universe is obtained, and possibilities of their detection are briefly discussed.Comment: 14 page

    Expression of Regulatory Platelet MicroRNAs in Patients with Sickle Cell Disease

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    Background: Increased platelet activation in sickle cell disease (SCD) contributes to a state of hypercoagulability and confers a risk of thromboembolic complications. The role for post-transcriptional regulation of the platelet transcriptome by microRNAs (miRNAs) in SCD has not been previously explored. This is the first study to determine whether platelets from SCD exhibit an altered miRNA expression profile. Methods and Findings: We analyzed the expression of miRNAs isolated from platelets from a primary cohort (SCD = 19, controls = 10) and a validation cohort (SCD = 7, controls = 7) by hybridizing to the Agilent miRNA microarrays. A dramatic difference in miRNA expression profiles between patients and controls was noted in both cohorts separately. A total of 40 differentially expressed platelet miRNAs were identified as common in both cohorts (p-value 0.05, fold change>2) with 24 miRNAs downregulated. Interestingly, 14 of the 24 downregulated miRNAs were members of three families - miR-329, miR-376 and miR-154 - which localized to the epigenetically regulated, maternally imprinted chromosome 14q32 region. We validated the downregulated miRNAs, miR-376a and miR-409-3p, and an upregulated miR-1225-3p using qRT-PCR. Over-expression of the miR-1225-3p in the Meg01 cells was followed by mRNA expression profiling to identify mRNA targets. This resulted in significant transcriptional repression of 1605 transcripts. A combinatorial approach using Meg01 mRNA expression profiles following miR-1225-3p overexpression, a computational prediction analysis of miRNA target sequences and a previously published set of differentially expressed platelet transcripts from SCD patients, identified three novel platelet mRNA targets: PBXIP1, PLAGL2 and PHF20L1. Conclusions: We have identified significant differences in functionally active platelet miRNAs in patients with SCD as compared to controls. These data provide an important inventory of differentially expressed miRNAs in SCD patients and an experimental framework for future studies of miRNAs as regulators of biological pathways in platelets. Š 2013 Jain et al

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Standalone vertex nding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011
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