1,168 research outputs found

    Potential for cogeneration of heat and electricity in California industry, phase 2

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    The nontechnical issues of industrial cogeneration for 12 California firms were analyzed under three categories of institutional settings: (1) industrial ownership without firm sales of power; (2) industrial ownership with firm sales of power; and (3) utility or third party ownership. Institutional issues were analyzed from the independent viewpoints of the primary parties of interest: the industrial firms, the electric utilities and the California Public utilities Commission. Air quality regulations and the agencies responsible for their promulgation were examined, and a life cycle costing model was used to evaluate the economic merits of representative conceptual cogeneration systems at these sites. Specific recommendations were made for mitigating measures and regulatory action relevant to industrial cogeneration in California

    Nonlinear dynamics of self-centring rocking steel frames using finite element models

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    Rocking post-tensioned steel frames capitalise on the use of rocking joints, and unbonded post-tensioning strands to provide self-centring action. Investigations on the complex and unconventional nonlinear dy- namics of tied rocking steel frames, exclusive of supplemental damping methods, are presently limited. Increasing levels of energy-dissipation reduce the probability of observing nonlinear dynamic phenomena such as co-existing (high/low) amplitude responses at and around the system’s nonlinear resonance. To this end, a finite element (FE) modelling framework is presented, validated and extended to multi-storey steel buildings. It is shown that the simulation strategies proposed enable an accurate representation of the complex nonlinear dynamics of self-centring structures, over a wide range of excitation frequencies and amplitudes. The methodology, applied to multi-storey steel frames, captures the presence of sub-harmonic resonances and higher-modes. It is also demonstrated that the additional demands observed in the rocking columns are the consequence of the asymmetry of the member boundary conditions

    Music and anxiety in hospitalized children

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    Purpose: Music is a method of stress reduction and could be used as a non-invasive therapeutic tool to relieve the pain and anxiety of patient. This study is designed to evaluate the role of music therapy on the level of anxiety in children aged 912 yearsold, in an academic hospital in Gorgan, northeast of Iran. Methods: Sixty hospitalized children were categorized into the intervention (case=30) and the control groups (N=30) by using a simple randomized method. The data gathering instruments were questionnaires which included demographic information and a trait anxiety inventory for children, the Spielberger test (STAIC). For the intervention group, for 2 days, 20 minutes (3 am-6 pm), the soothing rhythmic music of Johann Sebastian Bach was released through a tape recorder which was equipped with a headphone and then, the Spielberger questionnaires were refilled by each patient. The control group did not receive any intervention. Results: The results showed that the anxiety scores between the control and the intervention groups had no significant difference before the application of the music. The mean anxiety after the application of music in the control group was 49.4±7.2 and in the intervention group, it was 30.7±7.5. The results showed a significant difference between the mean anxiety in the control and the intervention groups (p<0.05). Conclusions: Our results showed that in hospitalized children, music therapy reduced the anxiety level

    The Omega deformed B-model for rigid N=2 theories

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    We give an interpretation of the Omega deformed B-model that leads naturally to the generalized holomorphic anomaly equations. Direct integration of the latter calculates topological amplitudes of four dimensional rigid N=2 theories explicitly in general Omega-backgrounds in terms of modular forms. These amplitudes encode the refined BPS spectrum as well as new gravitational couplings in the effective action of N=2 supersymmetric theories. The rigid N=2 field theories we focus on are the conformal rank one N=2 Seiberg-Witten theories. The failure of holomorphicity is milder in the conformal cases, but fixing the holomorphic ambiguity is only possible upon mass deformation. Our formalism applies irrespectively of whether a Lagrangian formulation exists. In the class of rigid N=2 theories arising from compactifications on local Calabi-Yau manifolds, we consider the theory of local P2. We calculate motivic Donaldson-Thomas invariants for this geometry and make predictions for generalized Gromov-Witten invariants at the orbifold point.Comment: 73 pages, no figures, references added and typos correcte

    Counting fermionic zero modes on M5 with fluxes

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    We study the Dirac equation on an M5 brane wrapped on a divisor in a Calabi--Yau fourfold in the presence of background flux. We reduce the computation of the normal bundle U(1) anomaly to counting the solutions of a finite--dimensional linear system on cohomology. This system depends on the choice of flux. In an example, we find that the presence of flux changes the anomaly and allows instanton corrections to the superpotential which would otherwise be absent.Comment: 14 pages. v2: reference added, typos corrected, few change

    Towards reduction of type II theories on SU(3) structure manifolds

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    We revisit the reduction of type II supergravity on SU(3) structure manifolds, conjectured to lead to gauged N=2 supergravity in 4 dimensions. The reduction proceeds by expanding the invariant 2- and 3-forms of the SU(3) structure as well as the gauge potentials of the type II theory in the same set of forms, the analogues of harmonic forms in the case of Calabi-Yau reductions. By focussing on the metric sector, we arrive at a list of constraints these expansion forms should satisfy to yield a base point independent reduction. Identifying these constraints is a first step towards a first-principles reduction of type II on SU(3) structure manifolds.Comment: 20 pages; v2: condition (2.13old) on expansion forms weakened, replaced by (2.13new), (2.14new

    Bioconjugated technetium carbonyls by transmetalation reaction with zinc derivatives

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    Altres ajuts: Acord transformatiu CRUE-CSICThe transmetalation reaction between zinc dithiocarbamates functionalized with organic groups and the cation fac-[Tc(HO)(CO)] has been studied as a new strategy to bind biomolecules to this radionuclide for preparing radiopharmaceuticals with high molar activity. All complexes were obtained in high yields by heating at moderate temperatures and without subsequent purification. The chemical identity was ascertained by HPLC comparison with the homologous rhenium complexes. Stability studies in cysteine solution and serum have shown a good stability of the coordination set fac-[Tc(CO)(SS)(P)]. Preliminary biological studies of the radiocomplex functionalized with D-(+)-glucosamine with carcinoma cells have been performed

    No-scale supersymmetry breaking vacua and soft terms with torsion

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    We analyze the conditions to have no-scale supersymmetry breaking solutions of type IIA and IIB supergravity compactified on manifolds of SU(3)-structure. The supersymmetry is spontaneously broken by the intrinsic torsion of the internal space. For type IIB orientifolds with O9 and O5-planes the mass of the gravitino is governed by the torsion class W_1, and the breaking is mediated through F-terms associated to descendants of the original N=2 hypermultiplets. For type IIA orientifolds with O6-planes we find two families of solutions, depending on whether the breaking is mediated exclusively by hypermultiplets or by a mixture of hypermultiplets and vector multiplets, the latter case corresponding to a class of Scherk-Schwarz compactifications not dual to any geometric IIB setup. We compute the geometrically induced mu-terms for D5, D6 and D9-branes on twisted tori, and discuss the patterns of soft-terms which arise for pure moduli mediation in each type of breaking. As for D3 and D7-branes in presence of 3-form fluxes, the effective scalar potential turns out to possess interesting phenomenological properties.Comment: 44 pages; several minor corrections and added reference
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