4,223 research outputs found

    Coherent Topological Charge Structure in CPN1CP^{N-1} Models and QCD

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    In an effort to clarify the significance of the recent observation of long-range topological charge coherence in QCD gauge configurations, we study the local topological charge distributions in two-dimensional CPN1CP^{N-1} sigma models, using the overlap Dirac operator to construct the lattice topological charge. We find long-range sign coherence of topological charge along extended one-dimensional structures in two-dimensional spacetime. We discuss the connection between the long range topological structure found in CPN1CP^{N-1} and the observed sign coherence along three-dimensional sheets in four-dimensional QCD gauge configurations. In both cases, coherent regions of topological charge form along membrane-like surfaces of codimension one. We show that the Monte Carlo results, for both two-dimensional and four-dimensional gauge theory, support a view of topological charge fluctuations suggested by Luscher and Witten. In this framework, the observed membranes are associated with boundaries between ``k-vacua,'' characterized by an effective local value of θ\theta which jumps by ±2π\pm 2\pi across the boundary.Comment: 26 page

    B(E2) value of even-even 108-112Pd isotopes by interacting boson model-1*

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    This work studies the systematic reduced transition probabilities B(E2), intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N= 62 to 66. The downward reduced transition probabilities B(E2) from gamma transition 8+ to 6+, 6+ to 4+, 4+ to 2+ and 2+ to 0+ states of even-even 108-112Pd isotopes were calculated by the Interacting Boson Model (IBM-1) and compared with the available previous experimental results. The ratio of the excitation energies of the first 4+ and the first 2+ excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The 108-112Pd isotopes show the O(6) symmetry

    Health and Safety Concerns: Quantitative Studies of Leaching of Metals from Glazed Surfaces of Traditional Ceramic Potteries

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    Traditional ceramic wares have been known as a source of heavy metals poisoning. Traditional ceramic potteries may be improperly glazed, and the glaze used to make the pottery may contain over amounts of heavy metals. These over glazed ceramic wares can release deadly metal into foodstuff and constitute health hazards. In this work, Quantitative studies were done according to ASTM C 738.81 (1982) leaching standard test methods for the determination of trace amount of selected metals from glazed surfaces of traditional ceramic potteries by 4% acetic and 2% citric acid standard solutions at different temperatures. Finally, leaching potential has been done using ICP-MS analysis. The capacity of each ceramic tableware sample ranged between 250 and 350ml. The ceramic wares selected randomly from products available in the local markets at Doha (Qatar), Cairo (Egypt) and Gharyan (Libya)

    Energy-momentum Density of Gravitational Waves

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    In this paper, we elaborate the problem of energy-momentum in general relativity by energy-momentum prescriptions theory. Our aim is to calculate energy and momentum densities for the general form of gravitational waves. In this connection, we have extended the previous works by using the prescriptions of Bergmann and Tolman. It is shown that they are finite and reasonable. In addition, using Tolman prescription, exactly, leads to same results that have been obtained by Einstein and Papapetrou prescriptions.Comment: LaTeX, 9 pages, 1 table: added reference

    Optimization of the Agar-gel Method for Isolation of Migrating Ascaris suum Larvae From the Liver and Lungs of Pigs

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    Experiments on use of an agar-gel method for recovery of migrating Ascaris suum larvae from the liver and lungs of pigs were conducted to obtain fast standardized methods. Subsamples of blended tissues of pig liver and lungs were mixed with agar to a final concentration of 1% agar and the larvae allowed to migrate out of the agar-gel into 0.9% NaCl at 38°C. The results showed that within 3 h more than 88% of the recoverable larvae migrated out of the liver agar-gel and more than 83% of the obtained larvae migrated out of the lung agar-gel. The larvae were subsequently available in a very clean suspension which reduced the sample counting time. Blending the liver for 60 sec in a commercial blender showed significantly higher larvae recovery than blending for 30 sec. Addition of gentamycin to reduce bacterial growth during incubation, glucose to increase larval motility during migration or ice to increase sedimentation of migrated larvae did not influence larvae recovery significantly

    Extending Shelf Life of Guava Fruits by Mint oil and UVC Treatments

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    A lot of quarantine methods have been developed to replace fumigants in the control of arthropods and microorganisms in post–harvest management of fruits and vegetables. That is, guava fruit is infested in Sudan by a number of hexapods which include Ceratitis capitata Weid., Ceratitis quinaria (Bez.), Certatitis cosyra WLK., Bactrocera invadens Drew, Trusta & White and Bactrocera zonata (Saunders).This study aims at using some uncommonly used treatments in improving the storability of guava fruits in Sudan. That is, UVC (ultraviolet rays type C) and coating with mint oil were used to disinfest guava from fruit flies at ambient temperature. The results, after 9 days bench storage, showed an infestation percentage of 20, 33 and 38% for mint, UVC and the control, respectively. The corresponding data for the range of infestation were 18, 20 and 48 and for the mean number of insects in infested fruits were 8.3, 8.8 and 15.2. The quality indexes studied reflected 9.5, 20.5 and 22.6% weight loss, for the mint oil, UVC and the control lots, respectively. The corresponding data for marketable retention (%) were 100, 10 and 13; the fruit firmness, 1.6, 0.3, and 0.1; acidity (%), 0.2 for all; ascorbic acid (mg/ 100 g pulp), 196, 190, and 194; reducing sugar (g/ 100g), 8.2, 7.6, and 7.6; sensory quality includes appearance (%), 84, 42, and 30; taste (%), 79, 41, and 34; flavor (%), 88, 42, and 40, respectively. These results revealed the edge of mint oil coating over UVC and the untreated lots

    Fast pyrolysis of halogenated plastics recovered from waste computers

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    The disposal of waste computers is an issue that is gaining increasing interest around the world. In this paper, results from the fast pyrolysis in a fluidized bed reactor of three different waste computer monitor casings composed of mainly acrylonitrile-butadiene-styrene (ABS) copolymer and two different waste computer body casings composed of mostly poly(vinyl chloride) (PVC) type polymers are presented. Preliminary characterization of the waste plastics was investigated using coupled thermogravimetric analysis-Fourier transform infrared spectrometry (TGA-FT-IR). The results showed that the plastics decomposed in two stages. For the ABS-containing monitor casings, aromatic and aliphatic material were released in the first and second stages. The PVC-containing computer body casing samples showed a first-stage evolution of HCl and a second stage evolution of aromatic and aliphatic material and further HCl. In addition, each of the five plastics was fast-pyrolyzed in a laboratory-scale fluidized bed reactor at 500 °C. The fluidized bed pyrolysis led to the conversion of most of the plastics to pyrolysis oil, although the two PVC computer body cases produced large quantities of HCl. The pyrolysis oils were characterized by GC-MS and it was found that they were chemically very heterogeneous and contained a wide range of aliphatic, aromatic, halogenated, oxygenated, and nitrogenated compounds
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