482,682 research outputs found

    Effect of Static Extraction TIME on Extraction Efficiencies Using On-line Supercritical Fluid Extraction-High Performance Liquid Chromatography for Lipoquinone Analysis in Activated Sludge

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    Analysis of microbial community is important for monitoring the performance of biological processes. One of the most simple, quantitative and high reproducible method for analysis of the microbial community is lipoquinone profile method. Lipoquinone is constituent of bacterial plasma membrane that is essential for electron transporter. Lipoquinone could be used as a biomarker to analyze the microbial community because in general one species or genus of bacteria has one dominant type of lipoquinone, thus any changes in the lipoquinone profile would reflect the changes in the microbial community. The method for lipoquinone determination in environmental sample is direct extraction using organic solvent and analysis using chromatography system. Since the method is tedious and uses a large amount of organic solvent, the on-line supercritical fluid extraction-high performance liquid chromatography (on-line SFE-HPLC) has been developed to simplify the method, and was successful determine lipoquinone compounds in activated sludges. The effect of static extraction time on extraction efficiencies of the lipoquinone was investigated in order to eliminate the water pump and methanol pump in the previous system. The CO2 was used as an extraction solvent. The 0.1 g of freeze dried activated sludge was placed into a 1 mL stainless steel extraction vessel and methanol was spiked into the sludge as a modifier. The SFE was connected to HPLC by using trapping column as an interface for collecting lipoquinone extracted from the sludge. The static extraction time was conducted by allowed the matrix to immersed in CO2 and methanol. When the static extraction time finished, the dynamic extraction time was carried out. The extracted and trapped lipoquinone then directly transferred to HPLC system for determination. In this study, the effect of static, dynamic extraction time and volume of spiked methanol were optimized using simplified on-line SFEHPLC for lipoquinone analysis. The best results in terms of extraction yield were obtained at 25 MPa, 45°C, 10 min static extraction time with 500 ”L methanol spiked, and 25 min dynamic extraction time with 0.9 mL min-1 CO2 flow rate. It was concluded that the developed method could simplify the online SFE-HPLC system of lipoquinone determination which is useful for a rapid and routine analysis of microbial community in activated sludge

    Laboratory Physics and Cosmology

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    We find five fundamental reasons demanding that any gravitational mass m, and the speed of light c, vary with cosmological time such that mc remains constant. This is required by the universal condition of conservation of momentum in a Universe with spatial homogeneity. We prove that this is consistent with Einstein's Theory of General Relativity. We call this effect a "MASS BOOM". At the LAB system no such time variations can be detected, unless we make comparisons with cosmological observations. We have to stress that the physical conditions implied by a time varying mass, together with a time varying speed of light, preserving the constancy of momentum, are compatible with Einstein's field equations. We then integrate his cosmological equations and find the solution for the cosmological scale factor a(t) proportional to the square of time, implying an apparent accelerated expansion for the Universe, as seen from the LAB frame. This is the interpretation given to recent observations obtained from the Supernova Type Ia. This determination of the scale factor a(t) is based upon a LAB interpretation and therefore is an apparent effect. On the other hand we note that the product ct being a constant determines the real Universe as a static one, of constant size. The observed red shift at the LAB system is due to a real shrinkage of the quantum world, due to the decrease in size of the quantum particles determined by a decreasing Planck's "constant".Comment: Accepted for publication in Physics Essays 200

    A low-energy determination of αs\alpha_s at three loops

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    We review one of the most accurate low-energy determinations of αs\alpha_s. Comparing at short distances the QCD static energy at three loops and resummation of the next-to-next-to leading logarithms with its determination in 2+1-flavor lattice QCD, we obtain αs(1.5 GeV)=0.336−0.008+0.012\alpha_s(1.5~{\rm GeV})=0.336^{+0.012}_{-0.008}, which corresponds to αs(MZ)=0.1166−0.0008+0.0012\alpha_s(M_Z)=0.1166^{+0.0012}_{-0.0008}. We discuss future perspectives.Comment: 9 pages, 8 figures, 4th International Conference on New Frontiers in Physics, Crete, August 2015 and XLV International Symposium on Multiparticle Dynamics, Wildbad Kreuth, October 201

    Assessment of the Overall Efficiency in WPT Stations for Electric Vehicles

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    The on-site assessment of the efficiency of a charging station is not a trivial process and is a topic of discussion for professionals. The efficiency of electric Vehicle Supply Equipment (EVSE), is an important parameter for both the user and the EVSE operator. This paper deals with a particular type of EVSE, using static wireless power transfer (WPT). This paper proposes a clear method to account for the parameters which can affect the correct determination of efficiency, such as in particular the accuracy of the meters and the effect of temperature. This work proposes a method to define the accuracy of the power and efficiency on-site assessment, and is aimed at clarifying that despite distorted waveforms at the charging stations, it is possible to reach a good accuracy in a wide temperature span (expanded uncertainty <0.5% between 5∘C and 40∘C). Analysis initiated from the measurement conditions and the actual waveforms recorded at two WPT EVSEs with differently rated power. This paper paves the way for the possibility of verifying class 0.5 meters on-site, desirable for this type of application. The paper also clarifies that despite the evident presence of voltage and current ripple at the batteries, the weight of the ripple power on the total power is nevertheless lower than 0.1%. Finally, the paper highlights how, for the correct measurement of the ripple, it would be advisable to calibrate the instrumentation in DC and in AC, at a frequency double that of the working frequency of the EVSE coil

    Concrete Static Stress Estimation Using Computer Vision-Based Digital Image Processing

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    Department of Urban and Environmental Engineering (Urban Infrastructure Engineering)As increasing interests about structural safety due to occasionally occurring collapse of structures and social infrastructures, efforts to identify and monitor the current state of structure are also increasing. Recently, most structures have been built of concrete, so identification of safety level of concrete structures becomes a critical issue. One of such techniques is to evaluate the current stress state in concrete. This technique is essential in various fields involved in an investigation of tensile stress of tendons in pre- and post-tensioned structures, building remodeling which needs to remove bearing walls and adds other foundations, and identification of load distribution in enlarged concrete structures. In other words, current stress level in concrete is an important factor to check the safety level of the structures in service. Although it is obvious that a technique for estimating the static stress level of concrete is essential, the method to identify the stress state of the currently used concrete structure is definitely limited. Several efforts for estimating the current stress state have been developed in previous research, including a stress-strain relationship based on elastic theory and a stress relaxation method (SRM) for concrete. These methods in the previous researches have made a certain contribution in this field but practical use in real structures is still inadequate. Therefore, an objective of this study is to develop a static stress estimation technique which can be applied to real concrete structures. This study proposes a method that can measure the static stress level of concrete by incorporating SRM and computer vision-based image processing. Applying a small damage to concrete specimen can release the current stress state and induce stress field change inside concrete around the damage. Computer vision-based measurement can measure the deformation due to this stress field change. This deformation measurement is used in the static stress estimation algorithm developed in this study. The proposed method is validated using several concrete specimens and consequently demonstrates the performance.clos

    String Breaking as a Mixing Phenomenon in the SU(2) Higgs Model

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    We study the potential of a static quark anti-quark pair in the confinement ``phase'' of the SU(2) Higgs model. Around separation r_b, the confining string of the gauge field breaks by formation of a dynamical pair of light quarks. The ground state and first excited state static potentials are determined by a variational technique from a matrix correlation in which suitably smeared gauge and Higgs fields enter. Our results at beta=2.4 clearly show string breaking (r_b ~ 1.9r_0). The investigation of properly defined overlaps confirms the interpretation of string breaking as a level crossing phenomenon between string-type and meson-type states. We study the scaling properties of the static potentials along a line of constant physics, varying the lattice spacing by a factor of 2. Our results show compatibility with scaling within tiny errors.Comment: 21 pages, 9 figure

    Resistance of Liposomal Sunscreen Formulations against Plain Water as well as Salt Water Exposure and Perspiration

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    The present in vivo investigation using a total of 30 healthy adult volunteers with Fitzpatrick skin type II examines the persistent efficacy of sunscreens using liposomal suspensions as the vehicle. Based on the COLIPA guidelines, the protective effect of a single application of 4 different liposomal sunscreen formulations (sun protection factors, SPFs: 50+, 30,25 and 15) against sunburn at the recommended amount of 2 mg/cm(2) was determined after exposure of the skin to plain water and salt water and after profuse perspiration. Under the influence of plain water, salt water and sweating, the SPF values of sunscreen 1 (labeled SPF of 50+) were reduced only marginally to 97, 96 and 99%, respectively, those of sunscreen 2 (labeled SPF of 30) to 97, 96 and 99%, respectively, those of sunscreen 3 (labeled SPE of 25) to 90, 83 and 91%, respectively, and those of sunscreen 4 (labeled SPF of 15) to 96, 96 and 95%, respectively. This set of data shows that despite plain water and salt water immersion or profuse sweating, the liposomal sunscreen formulation may deliver a long-lasting protective effect in everyday situations encountered by outdoor workers or during leisure activities. Copyright (C) 2010 S. Karger AG, Base

    Equal-time two-point correlation functions in Coulomb gauge Yang-Mills theory

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    We apply a functional perturbative approach to the calculation of the equal-time two-point correlation functions and the potential between static color charges to one-loop order in Coulomb gauge Yang-Mills theory. The functional approach proceeds through a solution of the Schroedinger equation for the vacuum wave functional to order g^2 and derives the equal-time correlation functions from a functional integral representation via new diagrammatic rules. We show that the results coincide with those obtained from the usual Lagrangian functional integral approach, extract the beta function, and determine the anomalous dimensions of the equal-time gluon and ghost two-point functions and the static potential under the assumption of multiplicative renormalizability to all orders.Comment: 33 pages, 7 figures with Feyman diagrams generated with pstricks; revised version with additional references and comments on possible applications added in the conclusions; accepted for publication in Nucl. Phys.
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