A Selective Separation Method for Slower‐Growing Bacteria from Marine Soils

Abstract

Egg lecithin greatly reduced the antibacterial activities of chlorhexidine gluconate (CHG). By using this antagonistic action, slower‐growing bacteria, for which a longer incubation time was needed for its growth, were isolated from marine soils. The growth of relatively faster‐growing bacteria, which formed visible colonies during a 3 day incubating period, was significantly inhibited by treatment with 8 µg of CHG per mL for 10 min, whereas the addition of egg lecithin to a final concentration of 2%, after the treatment, had no significant effect on the viability of slower‐growing bacteria.     

An algebraic–analytic framework for measurement theory

The goal of this paper is to present an algebraic–analytic framework for (static and dynamic) deterministic measurement theory, which we find to be fully adequate in engineering and natural science applications. The starting point of this paradigm is the notion of a quantity algebra of a measured system and that of a measuring instrument, underlying the causal linkages in classical ‘system + instrument’ interactions. This approach is then further enriched by providing a superimposed data lattice of measurement outcomes, intended to handle the information flow from the measured system to its measurand’s instrument. The original motivation for this algebraic–analytic setting for measurement was the authors’ earlier work (including Batitsky (1998) [1], Domotor (1992) [10], Domotor and Batitsky (2008) [11]), in which they express various concerns about the foundational adequacy of the well-known representational theory of measurement, henceforth acronymed RTM for short. There is a growing body of arguments and evidence, showing that, by and large, real-world measurements in the natural sciences and technology do not conform to the philosophical and mathematical assumptions of RTM. To make precise what we mean by all this, we begin by recalling the gist of our previous discussions of the philosophical rights and wrongs of the representational view of measurement. Then we move on to present an alternative algebraic–analytic measurement theory which, we believe, offers a natural account of classical deterministic measurement.     

An in-beam-line low-level system for nuclear reaction γ-rays

The applicability of nuclear γ-ray reactions to the impurity analysis of solids is generally limited by background radiation. In order to significantly improve the sensitivity of this method, low-level counting techniques have to be adopted. To this end a multiple shield system has been integrated into the beam line of the EN tandem accelerator. In this way, the background level as seen by a 10″×10″ NaI detector has effectively been reduced by a factor of about 100 over the energy region of 0.5–20 MeV. Thus, the detection limit for the ¹⁵N reaction with ¹H has been improved from about 0.1–1 at.% to about 10–100 at.ppm for normal and low-level operating conditions, respectively. A number of applications will be discussed and first results will be presented.     

An Elastic–Plastic Model for Single Shot-Peening Impacts

A model was developed for impacts of elastic perfectly plastic spherical particles with impact velocities up to 250 m/s. The model is based on the two master curves, for normalized pressure $\bar{H}$ and projected contact area c ², which both are functions of the representative strain Λ at maximum impact. The model and its parameters were fitted to finite element results for elastic perfectly plastic and strain rate-independent materials. It was applied to a wide range of materials with different ratio between yield stress and elastic properties, different ball sizes and impact velocities. The impact model predicted the results from finite element method for contact radius, maximum impact depth in both target and ball as well as remaining impact depth in target and ball. The remaining impact depth was determined from elastic spring back with Hertzian and quadratic pressure at maximum impact. The rebound velocity was also estimated by following the load-deformation path during spring back. If the strain rate-compensated yield stress was used for the master curve parameters, then the model predicted the impact results also for the investigated strain rate-dependent materials.     

An elastic–plastic asperity interaction model for sliding friction

A finite-element model of the interaction of an elastic–plastic asperity junction based on cylindrical or spherical asperities is used to predict sliding friction coefficients. The modelling differs from previous work by permitting greater asperity overlaps, enforcing an interface adhesional shear strength, and allowing material failure. The results of the modelling were also used to predict friction coefficients for a stochastic rough surface. The asperities were based on the titanium alloy Ti-6Al-4V, and the magnitudes of the predicted friction coefficients were generally representative of experimental measurements of sliding friction. The results suggest that friction arises from both plasticity and tangential interface adhesion.     

A New Method and Apparatus for High-Resolution γ-Radiographic Introscopy of Bulk Heavy-Metal Products and Blanks. First Application Results

Russian Journal of Nondestructive Testing - A $$\gamma $$-introscopy method and an installation using “electronic focusing” of $$\gamma $$-quanta transmitted through the studied object...     

An Automatic Data-Processing Technique for the High-Pressure Xenon γ-Ray Spectrometer

We describe an algorithm for radionuclide detection and identification by the -ray spectra recorded with a high-pressure xenon -ray spectrometer. The algorithm is based on the comparison of the measured spectra with the tabulated radionuclide data. The fitting criteria were formulated. The software package, implementing the algorithm and providing the execution of a complete cycle of -ray spectrum processing, was developed. The algorithm usability and efficiency were demonstrated by testing it with actual spectra.     

An experimental setup for studying specular reflection of hard γ quanta

An experimental setup is described on which the fact of specular reflection of hard γ quanta (E _γ ≤ 5 MeV) from a smooth amorphous surface has been experimentally established. Specular reflection is observed at sliding incidence of γ quanta onto a reflecting surface at angles of a few thousandths of a degree. The setup is composed of a microtron, a system of electron transportation to a bremsstrahlung target, the bremsstrahlung target generating an intense directed flux of electron bremsstrahlung γ quanta), a guiding system forming a ribbon beam of γ radiation with a width of ～1 cm and a thickness of ≈20 μm, a reflector (a liquid mercury surface or a glass plate), and a detection system containing the counting and spectrometric detectors located at a distance of 120 m from the bremsstrahlung target. Some experimental results are presented.     

Energy-Efficient Separation of Water–Petroleum Emulsion

Russian Engineering Research - Systems are considered for the dehydration of petroleum so as to separate water–petroleum emulsions. In particular, the low-temperature microwave (UHF)...     

An efficient technique for the indirect BEM for multi-frequency acoustic analysis using Green’s function approximation

We present an efficient technique for multi-frequency acoustic analysis by the variational indirect boundary element method. The system coefficient matrix of the boundary element method is frequency dependent and requires cumbersome computation in multifrequency acoustic analysis. To eliminate the frequency dependency of a system coefficient matrix of the boundary element method, the free space Green’s function is approximated using Taylor series. Unlike the existing Taylor series expansion method, the present technique deals with the approximated series of the Green’s function using matrix decomposition and multiplication. For multi-frequency acoustic analysis, the coefficient matrix of the frequency independent system is calculated only at the first frequency; from the remaining frequencies, it is calculated as the product of the wave number matrix and the frequency independent coefficient matrix at the first frequency. The efficiency of the present technique is demonstrated through numerical examples. The results are compared with those of the conventional indirect method and the existing series expansion method by Wang.     

An improved tool–holder model for RCSA tool-point frequency response prediction

In addition to the precise kinematic motions of the machine tools and spindles, machining accurate parts necessitates controlling the dynamic behavior of the tool tip with respect to the workpiece. High-fidelity models of tool-tip dynamics can be used to select operating parameters that improve the accuracy by reducing the effect of vibrations. To effectively model the tool-tip dynamics for arbitrary tool-and-holder combinations using the receptance coupling substructure analysis (RCSA) technique, highly accurate and numerically efficient models of the tool–holder dynamics are needed. In this paper, we present a tool–holder model that incorporates a spectral-Tchebychev technique with the Timoshenko beam equation to obtain a completely parameterized solution. Comparison of the tool–holder model to a three-dimensional finite elements solution shows that the dynamic behavior is captured with sufficient accuracy. The tool–holder model is then coupled with the experimentally determined spindle–machine dynamics through RCSA to realize a model of the tool-tip dynamics. The coupled model is validated through experiments for three different tool overhang lengths. The presented technique can be used to predict the tool-tip dynamics for different tool-and-holder combinations and for optimization studies without the need for extensive experimentation.     

An improved algorithm for McDowell’s analytical model of residual stress

The analytical model for two-dimensional elastoplastic rolling/sliding contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volumeconstancy of plastic deformation, an improved algorithm for McDowell’s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell’s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell’s model under the same simulation conditions.     

基于Marching Cubes与Ray Casting的医学图像三维重建

本文研究了医学图像三维面绘制和体绘制的典型算法 Marching Cube 和 Ray Casting 的原理和三维可视化工具包VTK的实现机制,在VC 6.0平台下,利用VTK分别实现了基于上述算法的DICOM格式的CT序列图像三维重建,并给出了关键算法和3D可视化结果.     

基于Ray Casting的医学体数据场绘制算法

在医学体可视化中,Ray Casting算法由于具有高的计算需求、模糊的绘制质量和复杂的分类等缺陷,限制了该算法的进一步应用。为此,本文定义了一种多种因素相结合的光学属性赋值方法,该方法将物体距离视点的距离与物体距离光源的距离有效结合起来。在此基础上提出了一种高效精确的医学体绘制算法,该算法首先将医学体数据场进行分类,对于前景体素集采用LOD(Layer of Detail)技术进行重采样,进而将采样点用上述定义进行赋值;最后将背景体素采用基于空间跳跃的加速技术进行显示。实验结果表明对于512×512×482×2 Byte大小的体数据,在普通微机上能够达到2.5 fps的绘制速度;而且组织器官显示清晰,符合人的视觉特征。     

An ion pulse ionization chamber for spectrometric measurements of low surface α activities

The design of a pulse ionization chamber for measuring the surface αactivity of various samples is described. When used together with the appropriate methods for recording and processing the signals, a low-background spectrometer based on this chamber is able to ensure a high sensitivity in direct measurements of ultralow surface α activities. This approach offers a solution to the problem of controlling superpure materials used in detectors for studying rare nuclear processes with a broken equilibrium in the decay chains of the uranium and thorium series. A procedure for modeling the shape of the current pulses according to the orientation of α-particle tracks and their location inside the chamber is described. Results obtained with an α source, as well as with copper and VM2000 light-reflecting film samples, are presented.