2,355 research outputs found

    Mapping of noise pollution by different interpolation methods in recovery section of Ghandi telecommunication Cables Company

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    Background: Noise pollution and workers\u27 noise exposure are common in industrial factories in Iran. In order to reduce this noise pollution, evaluation and investigation of noise emission are both necessary. In this study, different noise mapping methodsare used for determining the distribution of noise. Materials and Methods: In the present study, for preparing a noise map in a hall of an industrial factory, sampling was carried out in 6×6 m grid. After data normalization the variogram was developed. For interpolation of mentioned parameter, kriging and Inverse Distance Weighting methods were used. The best model for interpolation was selected by cross validation and error evaluation methods, such as Route Mean Square Error(RMSE). Results: The results showed that kriging method is better than other methods for prediction of noise property. The noise map was prepared, using the best interpolation method in Geographical Information System environment. Conclusion: Workers in this industrial hall were exposed to noise which is mainly induced by noisy machines. Noise maps which were produced in this study showed the distribution of noise and, also revealed that workers suffer from serious noise pollution

    Long-range interactions between an atom in its ground S state and an open-shell linear molecule

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    Theory of long-range interactions between an atom in its ground S state and a linear molecule in a degenerate state with a non-zero projection of the electronic orbital angular momentum is presented. It is shown how the long-range coefficients can be related to the first and second-order molecular properties. The expressions for the long-range coefficients are written in terms of all components of the static and dynamic multipole polarizability tensor, including the nonadiagonal terms connecting states with the opposite projection of the electronic orbital angular momentum. It is also shown that for the interactions of molecules in excited states that are connected to the ground state by multipolar transition moments additional terms in the long-range induction energy appear. All these theoretical developments are illustrated with the numerical results for systems of interest for the sympathetic cooling experiments: interactions of the ground state Rb(2^2S) atom with CO(3Π^3\Pi), OH(2Π^2\Pi), NH(1Δ^1\Delta), and CH(2Π^2\Pi) and of the ground state Li(2^2S) atom with CH(2Π^2\Pi).Comment: 30 pages, 3 figure

    Dirac particle in a spherical scalar potential well

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    In this paper we investigate a solution of the Dirac equation for a spin-12\frac{1}2 particle in a scalar potential well with full spherical symmetry. The energy eigenvalues for the quark particle in s1/2s_{1/2} states (with κ=−1\kappa=-1) and p1/2p_{1/2} states (with κ=1\kappa=1) are calculated. We also study the continuous Dirac wave function for a quark in such a potential, which is not necessarily infinite. Our results, at infinite limit, are in good agreement with the MIT bag model. We make some remarks about the sharpness value of the wave function on the wall. This model, for finite values of potential, also could serve as an effective model for the nucleus where U(r)U(r) is the effective single particle potential.Comment: 9 pages, 8 figures, revtex4, version to appear in PR

    Overlapping Resonances Interference-induced Transparency: The S0→S2/S1S_0 \to S_2/S_1 Photoexcitation Spectrum of Pyrazine

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    The phenomenon of "overlapping resonances interference-induced transparency" (ORIT) is introduced and studied in detail for the S0→S2/S1S_0 \to S_2/S_1 photoexcitation of cold pyrazine (C4_4H4_4N2_2). In ORIT a molecule becomes transparent at specific wavelengths due to interferences between envelopes of spectral lines displaying overlapping resonances. An example is the S2↔S1S_2\leftrightarrow S_1 internal conversion in pyrazine where destructive interference between overlapping resonances causes the S0→S2/S1S_0 \to S_2/S_1 light absorption to disappear at certain wavelengths. ORIT may be of practical importance in multi-component mixtures where it would allow for the selective excitation of some molecules in preference to others. Interference induced cross section enhancement is also shown.Comment: 13 pages, 7 figure

    Antioxidant and antihemolytic activities of methanol extract of Hyssopus angustifolius

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    This study was designed to evaluate antioxidant and antihemolytic activities of Hyssopus angustifolius flower, stem and leaf methanol extracts by employing various in vitro assays. The leaf extract showed the best activity in DPPH (63.2 ± 2.3 μg mL-1) and H2O2  (55.6 ± 2.6 μg mL-1) models compared to the other extracts. However, flower extract exhibited the highest Fe2+ chelating activity (131.4 ± 4.4 μg mL-1). The extracts exhibited good antioxidant activity in linoleic acid peroxidation and reducing power assays, but were not comparable to vitamin C. The stem (23.58 ± 0.7 μg mL-1) and leaf (26.21 ± 1 μg mL-1) extracts showed highest level of antihemolytic activity than the flower extract

    How to Measure the Quantum State of Collective Atomic Spin Excitation

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    The spin state of an atomic ensemble can be viewed as two bosonic modes, i.e., a quantum signal mode and a cc-numbered ``local oscillator'' mode when large numbers of spin-1/2 atoms are spin-polarized along a certain axis and collectively manipulated within the vicinity of the axis. We present a concrete procedure which determines the spin-excitation-number distribution, i.e., the diagonal elements of the density matrix in the Dicke basis for the collective spin state. By seeing the collective spin state as a statistical mixture of the inherently-entangled Dicke states, the physical picture of its multi-particle entanglement is made clear.Comment: 6 pages, to appear in Phys. Rev.
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