1,721,273 research outputs found
EMP coupling to coaxial shielded cables
No full textA method for determining the effects induced within shielded cables by a high-altitude nuclear electromagnetic pulse (EMP), represented as a plane wave, is presented. The cable is regarded as a multiconductor line in which the EMP sources are impressed on the shield. An efficient matrix procedure permits simultaneous calculation of transient voltages and currents at any point on each conductor. This procedure, which is based on transmission-line theory, involves modal propagation and reflection matrix operators. The method of analysis permits fast calculation of voltage and current in the shield and inner conductor, whatever the terminal impedance may be. Comparison of the results obtained by applying the single and the multiconductor approaches reveals a few significant differences in the case of the braided-shield cables which become more important as lengths increase, as well as in given closing conditions
Induced fast transients in multiconductor shielded cables
No full textThe coupling of fast transient electromagnetic fields to lossy multiconductor shielded cables is considered. Calculation of the transient responses calls for the development of models simulating the cable, the incident field and the impressed sources. Accurate models are developed to simulate a multiconductor cable with a multilayer braided-shield and multiple parallel inner conductors or twisted-wire pairs. The incident field is the sum of the primary field, represented as a plane wave, and the wave reflected from the ground. The cable response is obtained in the frequency domain by means of an efficient matrix procedure, based on the transmission-line theory, which involves Thevenin-equivalent representation. The transient waveforms for any terminal load condition are computed by an inverse discrete Fourier transformation. The theoretical procedure is applied for evaluating transient voltages and currents induced by an EMP source on a bifilar twisted-wire line, with and without shield, above an aluminium or a ground plane
Conformational behavior and magnetic properties of a nitroxide amino acid derivative in vacuo and in aqueous solution
No full textThe conformational behavior and magnetic properties of the R-acetylamino, N′-methylamide derivative of
TOAC(4-amino-2,2,6.6-tetramethylpiperidine-1-oxyl-4-carboxylic acid) have been investigated in vacuo and
in aqueous solution by an integrated computational approach including density functional, post-Hartree
Fock, and continuum solvent models. According to our computations, piperidine rings with an equatorial
placement of the nitroxide moiety are more stable by about 1 kcal/mol than their axial counterparts both in
vacuo and in aqueous solution. With respect to natural residues, TOAC shows a marked preference for helical
conformers, which is further enhanced by polar solvents. A comparison with other CR-tetrasubstituted residues
points out the difference between cyclic and open-chain substituents. The nitrogen isotropic hyperfine coupling
constants (AN) of folded TOAC conformers are similar to those of other nitroxides involving six-membered
rings and are well reproduced by a composite QM/QM/PCM model. The AN values of extended TOAC
conformers are significantly lower because of the constrained nearly planar structure of the piperidine ring
Microonde e prodotti agro-alimentari
Full text linkI trattamenti assistiti da microonde dei prodotti agro-alimentari,
possono costituire un valido strumento per migliorare le performance delle operazioni unitarie tradizionali tipiche dell’industria alimentare, per ottenere cibi con un elevato profilo
nutrizionale oltre che sanitizzati, edibili e conservabili
Onset of Instability in Sheared Gas Fluidized Beds.
No full textThe idea behind this work is to use the stabilizing effect of shear to homogenize bubbling gas fluidized beds. Essentially, we argue that, by increasing the shear, we increase the particle diffusivity, therefore enhancing the tendency of the particles to distribute uniformly in the bed. Although similar effects are known to play important roles in the diffusion of particles suspended in viscous liquids at very low Reynolds number, in this work we present the first evidence that this effect might be relevant also when the suspending fluid is a gas
Adverse events in rheumatoid arthritis patient with etanercept therapy: The appearance of osteomalacia
No full textRheumatoid arthritis (RA) is a systemic autoimmune disease of unknown origin that predominantly involves synovial tissue. RA affects 0.5-1% of the global population, with females affected more frequently than males. Patients receiving standard care for RA have significantly better status in 2000 than in 1985, associated with aggressive treatment strategies, prior to the introduction of biologic agents. Disease-modifying antirheumatic drugs (DMARDs) decrease clinical signs and symptoms in RA. Methotrexate, leflunomide and biological agents are analyzed. Glucocorticoids have long been recognized to have beneficial effects in RA. Rickets and osteomalacia are metabolic bone diseases due to a mineralization defect as principal pathophysiology. The Autors present a case report on a female patient with RA in treatment con etanercept and with osteomalacia (secondary?)
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