scholarly journals Modern Displacement Measuring Systems Used in Geotechnical Laboratories: Advantages and Disadvantages

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4139
Author(s):  
Małgorzata Jastrzębska

The paper presents the contemporary displacement measurement systems used in geotechnical laboratories during the determination of soil precise mechanical parameters, e.g., the shear modules G: initial and in the range of small and very small strains. In the laboratory, researchers use standard sensors for measuring deformation, pressure, and force as well as modern measuring systems such as linear variable differential transformers (LVDT), proximity transducers (PT), magnetic encoder sensors with fiber Bragg grating (FBG), or methods based on laser or X-ray measurement. None of the measurements are universal and their use depends on the type of soil (cohesive, non-cohesive), its condition (loose or dense, stiff or very soft), and its characteristic properties (e.g., organic soil, swelling soil). This study points out the interesting equipment solutions and presents the guidelines for selecting appropriate methods of deformation measurement.

2005 ◽  
Vol 38 (4) ◽  
pp. 678-684 ◽  
Author(s):  
Balder Ortner

A method for the X-ray determination of lattice-plane distances is given. Similar to Bond's method, it is based on the measurement of rocking curves, with some advantages and disadvantages compared with the former method. The new method is especially designed for single-crystal stress measurement. Its usefulness is demonstrated in two examples of lattice-constant and stress measurement.


This work reviews measurement systems applied for static and dynamic detection of object coordinates as well as acquiring information of their position at various distances. The market of measurement systems based on video cameras has been analyzed. Their classification is presented, fields of application are described, advantages and disadvantages are summarized for each type of measurement systems. In addition, it has been revealed that the frequency and extent of measurement errors depend not only on the quality on system components but also on numerous other factors, such as light flare, microvibrations, thermal expansion, etc. The review of measurement systems is necessary for determination of the most efficient method of conversion of video surveillance system into measurement system.


2017 ◽  
Vol 9 (4) ◽  
pp. 33
Author(s):  
Joao Antonio Santos Dias Fonseca ◽  
Antonio Baptista ◽  
Ma Joao Martins ◽  
Joao Paulo N. Torres

Optical measuring systems came to offer new ways to determine distances, deformations or vibrations through more accurate and greater range methods. Technological progress has allowed a significant improvement of several components, including the optical ones. Thus, the development of essential measurement methods is crucial to keep up with technological advances.In this paper, the three basic methods of measurement are studied – triangulation, telemetry and interferometry, covering their main applications, advantages and disadvantages, and theoretically substantiating each of the methods. The results of simulation routines for each method are shown along this work. For the triangulation method we made two experiments which demonstrate the functioning of the method in measuring distances and surfaces.For the telemetry method, experimental setups were studied to apply the method of pulse telemetry and phase comparison telemetry to measure distances,Thus, it is intended to set up the basis for the future development of more complex methods.


2020 ◽  
Vol 6 (1) ◽  
pp. 5-14
Author(s):  
Timur A. Raianov

In recent years, modern torque measurement systems have become very popular. they are used in road, rail, aviation and ship transport, as well as in the pulp, paper, and metallurgical industries. These metrological systems provide accurate torque measurement in difficult operating conditions as well as in aggressive environments. Thanks to the introduction of microprocessors in these devices, it became possible to increase the speed, it became possible to connect automatic torque tracking systems via a network interface to a single automatic control center and to perform remote control of torque sensors. With the use of modern software increases communication automatic torque measurement systems. Various software models are being developed for automatic torque measurement systems that have the ability to either partially simulate this system or work as an assistant device adapting automatic measurement systems to various uncertainties such as ambient temperature and properties of ferromagnetic materials. Safety of operation of transport systems, load-lifting devices and production facilities is increased. The purpose of this article is to review and analyze new types of torque sensors well-known manufacturers. The design and composition of modern measuring systems are considered and their advantages and disadvantages are analyzed. The technical description for each of the torque converters is given.


Author(s):  
Gilbert G. Ahlstrand ◽  
Richard J. Zeyen

Numerous plant pathological investigations have been published where pathologists determined elemental differences between diseased and healthy plant tissue using unfractured bulk specimens and energy dispersive x-ray microanalysis (EDX). In these studies effects of specimen preparation procedures were largely ignored (1). Our objective was to compare bulk specimen preparation procedures using healthy leaf epidermal (surface) cells of barley, Hordeum vulgare, (Fig. 1) to determine advantages and disadvantages of each procedure for reference to future pathological work using EDX. Three preparation procedures were compared: 1) Frozen-hydrated (FH) specimens to maintain soluble and insoluble elements in situ; 2) Freeze-dried (FD) specimens to maintain total soluble and insoluble elements and allow deeper beam penetration than does FH, and; 3) Formalin/acetic acid/ethanol (FAA) fixed specimens, dehydrated in ethanol, and critical point dried (CD) using CO2, for determination of elemental loss in liquid fixatives (2,3).Aluminum specimen stubs were colloidal graphite coated (leaf segments attached to graphite areas) leaving clean Al margins for calibration.


1968 ◽  
Vol 22 (5) ◽  
pp. 415-419 ◽  
Author(s):  
Ursula M. Cowgill

A method is described, employing as the sample bottom mud from Linsley Pond, North Branford, Connecticut, for the determination of all detectable exchangeable cations lying between lithium and uranium on the periodic table. Dried (48 h 110°C) and ground (200 mesh) lake mud samples are leached successively with IN, pH 6.9 ammonium acetate. Another set of similarly prepared samples are leached with doubly distilled deionized water. The leachate is made up to 100 ml. This volume is then added to a beaker containing two grams of terephthalic acid. The liquid is evaporated on to the water-insoluble terephthalic acid. The dried material is ground and pressed into a pellet. Another set of samples is treated in a similar fashion except that methyl cellulose is used as a substrate. The advantages and disadvantages of the two substrates are discussed. The pressed pellets containing the absorbed detectable exchangeable cations are examined with a G. E. x-ray emission spectroscope for those elements present between fluorine and uranium, and the lighter elements are examined by use of optical emission. The method in both cases is described.


2012 ◽  
Vol 323-325 ◽  
pp. 61-67 ◽  
Author(s):  
Raynald Gauvin ◽  
Nicolas Brodusch ◽  
Pierre Michaud

This paper present the determination of concentration profiles of an Mg Al diffusion couple that was obtained with a high resolution field emission scanning electron microscope, the Hitachi SU-8000 equipped with a SDD EDS detector. From these concentration profiles, the inter-diffusion coefficient is determined with the Boltzmann-Matano technique. The advantages and disadvantages of working at high and low beam energy for quantitative x-ray microanalysis are highlighted. The f ratio method is used in this work to convert the x-ray intensities into composition.


1957 ◽  
Vol 1 ◽  
pp. 367-386 ◽  
Author(s):  
Farrell W. Lytle ◽  
James I. Botsford ◽  
Henry A. Heller

AbstractAn X-ray emission spectrographic method of analysis is presented for the determination, of rare earth elements in fractions obtained from bastnaesite ore. The method includes the determination of yttrium, thorium, lanthanum., and the rare earth elements in various complex mixtures. The analysis technique is based upon comparing the samples to synthetic standards approximating the composition of the samples. Working curves are plotted on an absolute intensity basis, with, no correction for background. Examples of working curves and the analyses of typical rare earth concentrates are included. The selection of spectral lines for the various sample matrices is discussed. A special technique is used for samples in which rapid hydration and carbonation occurred.By analyzing synthetic samples of known composition, the accuracy of the method was determined. The error of analysis was about 3 per cent of the amount present in the range from 5 to 100 per cent and about 7 per cent in the 0.2 to 5 per cent range. A maximum of about 40 samples per day may be analyzed for 7 elements each. The advantages and disadvantages of the method are discussed.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Huali Wang ◽  
Feng Cao ◽  
Jiaqi Yang ◽  
Yongjuan Wu ◽  
Lin Wang

Imaging methods for gastrointestinal diseases were based on X-ray imaging until the 1970s, but the development of fiberoptic endoscopy in the 1980s has replaced X-ray imaging. Endoscopy can directly observe the location, size, scope, and color of lesions and obtain pathological results through biopsy, while ligation and other treatments can be performed on polyps and other lesions. Studies have shown that multilayer spiral computed tomography (CT) examination after standardized gastrointestinal preparation and full use of the advantages of various 3D postprocessing reconstruction techniques are of great clinical value in the detection of gastrointestinal diseases, determination of the nature of lesions, localization of lesions, and staging of gastrointestinal malignancies and can make up for the shortcomings of fiberoptic endoscopy, and various 3D postprocessing reconstruction modes have their own advantages and disadvantages. Among them, conventional CT cross-sectional images are the basic images for the diagnosis of various gastric testicular lesions. Axial images, especially thin-layer axial images, can detect the absolute majority of lesions, but there are limitations in observing the anatomical position of lesions, invasion of surrounding tissues, lymph node metastasis, vascularity, and determination of the stage of malignant tumors.


Author(s):  
H.J. Dudek

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S


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