Measurement Techniques

7 Key excerpts on "Measurement Techniques"

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  eBook - ePub

  System and Measurements

  • Yong Sang(Author)
  • 2020(Publication Date)
  • De Gruyter

    (Publisher)

  1  Introduction to measurement technology

  System and measurements is an important technological course in mechanical engineering education, which provides students with basic concepts and the fundamental principles of measurement such as experimental methods, calibration techniques, signal conditioning methods, real-time acquisition and processing of field data, selected sensors for mechanical engineering and display of data results. After learning this course, students will acquire the following abilities:

  1. An ability to grasp the methods of data acquisition and data processing
  2. An ability to analyze instruments with different input conditions (zeroth-order system, first-order system and second-order system)
  3. An ability to apply the sampling and signal conditioning principles learned in the classroom to measuring instruments
  4. An ability to use software and hardware for data acquisition
  5. An ability to synthesize an individual data acquisition project
  6. An ability to select the suitable sensors for temperature, displacement, force, acceleration, pressure and flow and the corresponding instrumentations
  7. An ability to describe experimental facilities and experimental procedures, collect data, write reports, analyze data and represent field data
  8. An ability to complete group work and share results with others

  In this chapter, students will know the history of measurement technology, basic concepts of measurement technology, applications of measurement technology, new trends of measurement technology and world’s famous manufacturers in the measurement field.

  1.1  History of measurement technology

  The emergence of measurement technology can be traced back to the distant ancient times, and the development of barter trade promoted the measurement of weight and the emergence of scale. Original measurement technologies are also used in other areas, such as measuring buildings and land, measuring calendar time and measuring astronomical geography. In ancient times, people can accurately measure the angle of refraction of light and determine the meridian arc of the earth. In the sixteenth and eighteenth centuries, the rapid development of physics greatly facilitated the advancement of measurement technology. Physics based on experiments relies entirely on measurement technologies, and has invented some advanced measuring devices such as microscopes, barometers and thermometers. At the turn of the seventeenth century, measurement accuracy was further improved, using an accurate astronomical measurement device that enabled Johannes Kepler to determine the rotation of the planet in an elliptical orbit. Great scientists such as Galileo Galilei and Isaac Newton pioneered measurement theory and developed many instruments based on physical phenomena.

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  Test and Measurement: Know It All

  • Jon S. Wilson, Stuart Ball, Creed Huddleston, Edward Ramsden, Dogan Ibrahim(Authors)
  • 2008(Publication Date)
  • Newnes

    (Publisher)

  Part I. Measurement Technology and Techniques

  Passage contains an image

  Chapter 1. Fundamentals of Measurement

  1.1. Introduction

  Metrology, or the science of measurement, is a discipline that plays an important role in sustaining modern societies. It deals not only with the measurements that we make in day-to-day living, such as at the shop or the petrol station, but also in industry, science, and technology. The technological advancement of the present-day world would not have been possible if not for the contribution made by metrologists all over the world to maintain accurate measurement systems.

  The earliest metrological activity has been traced back to prehistoric times. For example, a beam balance dated to 5000 bc has been found in a tomb in Nagada in Egypt. It is well known that Sumerians and Babylonians had well-developed systems of numbers. The very high level of astronomy and advanced status of time measurement in these early Mesopotamian cultures contributed much to the development of science in later periods in the rest of the world. The colossal stupas (large hemispherical domes) of Anuradhapura and Polonnaruwa and the great tanks and canals of the hydraulic civilization bear ample testimony to the advanced system of linear and volume measurement that existed in ancient Sri Lanka.

  There is evidence that well-established measurement systems existed in the Indus Valley and Mohenjo-Daro civilizations. In fact the number system we use today, known as the Indo-Arabic numbers, with positional notation for the symbols 1–9 and the concept of zero, was introduced into western societies by an English monk who translated the books of the Arab writer Al-Khawanizmi into Latin in the 12th century.

  In the modern world metrology plays a vital role to protect the consumer and to ensure that manufactured products conform to prescribed dimensional and quality standards. In many countries the implementation of a metrological system is carried out under three distinct headings or services, namely, scientific, industrial, and legal metrology.

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  Theory and Design for Mechanical Measurements

  • Richard S. Figliola, Donald E. Beasley(Authors)
  • 2019(Publication Date)
  • Wiley

    (Publisher)

  1 Basic Concepts of Measurement Methods 1.1 Introduction We take measurements every day. We routinely read the temperature of an outdoor thermometer to choose appropriate clothing for the day. We add exactly 5.3 gallons (about 20 liters) of fuel to our car fuel tank. We use a tire gauge to set the correct car tire pressures. We monitor our body weight. And we put little thought into the selection of instruments for these measurements. After all, the instruments and techniques are routine or provided, the direct use of the information is clear to us, and the measured values are assumed to be good enough. But as the importance and complexity increases, the selection of equipment and techniques and the quality of the results can demand considerable attention. Just contemplate the various types of measurements and tests needed to certify that an engine meets its stated design specifications. The objective in any measurement is to assign numbers to variables so as to answer a question. The information acquired is based on the output of some measurement device or system. We might use that information to ensure that a manufacturing process is executing correctly, to diagnose a defective part, to provide values needed for a calculation or a decision, or to adjust a process variable. There are important issues to be addressed to ensure that the output of the measurement device is a reliable indication of the true value of the measured variable. In addition, we must address some important questions: 1. How can a measurement or test plan be devised so that the measurement provides the unambiguous information we seek? 2. How can a measurement system be used so that the engineer can easily interpret the measured data and be confident in their meaning? There are procedures that address these measurement questions. At the onset, we want to stress that the subject of this text is real-life–oriented.

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  Theory and Design for Mechanical Measurements

  • Richard S. Figliola, Donald E. Beasley(Authors)
  • 2015(Publication Date)
  • Wiley

    (Publisher)

  Chapter 1 Basic Concepts of Measurement Methods 1.1 INTRODUCTION We make measurements every day. Consider the common measurements illustrated in Figure 1.1. We routinely read the temperature of an outdoor thermometer to choose appropriate clothing for the day. We expect to have exactly 10 gallons or liters of fuel added to our tank when that volume is indicated on a fuel pump. And we expect measuring cups to yield correct quantities of ingredients in cooking. We put little thought into the selection of instruments for these routine measurements. After all, the direct use of the data is clear to us, the type of instruments and techniques are familiar to us, and the outcome of these measurements is not important enough to merit much attention to features like improved accuracy or alternative methods. But when the stakes become greater, the selection of measurement equipment and techniques and the interpre- tation of the measured data can demand considerable attention. Just contemplate how you might verify that a new engine is built as designed and meets the power and emissions performance specifications required. But first things first. The objective in any measurement is to answer a question. So we take measurements to establish the value or the tendency of some variable, the results of which are specifically targeted to answer our question. The information acquired is based on the output of the measurement device or system. There are important issues to be addressed to ensure that the output of the measurement device is a reliable indication of the true value of the measured variable. In addition, we must address the following important questions: 1. How can a measurement or test plan be devised so that the measurement provides the unambiguous information we seek? 2. How can a measurement system be used so that the engineer can easily interpret the measured data and be confident in their meaning? There are procedures that address these measurement questions.

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  Quality Assurance of Chemical Measurements

  • John K. Taylor(Author)
  • 2018(Publication Date)
  • Routledge

    (Publisher)

  CHAPTER 9

  Principles of Measurement

  Measurements usually are made because a quantitative value for some substance or constituent thereof is needed for some purpose. Ordinarily, one speaks of measurement or determination of the parameter of interest, but this is seldom the case. Rather, one must be content with measuring some property for which there is an instrument response that can be related to the concentration or amount of the substance of interest in a sample of the material or in some other material (e.g., a solution) prepared from the sample. Furthermore, a suitable system should be available to make the desired measurement, and the system should be maintained in a state of statistical control throughout the measurement process [46]. A further requirement is that the measurement system can be and is calibrated with respect to the substance of interest.

  Terminology

  The nomenclature of methodology often is loosely used, so a short discussion of this topic may be in order at this point. The hierarchy of methodology, proceeding from the general to the specific, may be considered as technique → method → procedure → protocol. These terms may be defined as follows:

  Technique	– A scientific principle that has been found useful for providing compositional information.
  Method	– An adaptation of a technique to a specific measurement problem.
  Procedure	– The written directions considered to be necessary to utilize a method.
  Protocol	– A set of definitive instructions that must be followed, without exception, if the analytical results are to be accepted for a specific purpose.

  In addition to these, several other terms are used when describing methodology or measurement data. Some of them are:

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  Measurement and Instrumentation Principles

  • Alan S. Morris(Author)
  • 2001(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  Part 1 Principles of Measurement . This Page Intentionally Left Blank 1 Introduction to measurement Measurement Techniques have been of immense importance ever since the start of human civilization, when measurements were first needed to regulate the transfer of goods in barter trade to ensure that exchanges were fair. The industrial revolution during the nineteenth century brought about a rapid development of new instruments and Measurement Techniques to satisfy the needs of industrialized production tech-niques. Since that time, there has been a large and rapid growth in new industrial technology. This has been particularly evident during the last part of the twentieth century, encouraged by developments in electronics in general and computers in partic-ular. This, in turn, has required a parallel growth in new instruments and Measurement Techniques. The massive growth in the application of computers to industrial process control and monitoring tasks has spawned a parallel growth in the requirement for instruments to measure, record and control process variables. As modern production techniques dictate working to tighter and tighter accuracy limits, and as economic forces limiting production costs become more severe, so the requirement for instruments to be both accurate and cheap becomes ever harder to satisfy. This latter problem is at the focal point of the research and development efforts of all instrument manufacturers. In the past few years, the most cost-effective means of improving instrument accuracy has been found in many cases to be the inclusion of digital computing power within instruments themselves. These intelligent instruments therefore feature prominently in current instrument manufacturers’ catalogues. 1.1 Measurement units The very first measurement units were those used in barter trade to quantify the amounts being exchanged and to establish clear rules about the relative values of different commodities.

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  Micromachining of Engineering Materials

  • J.A. McGeough(Author)
  • 2001(Publication Date)
  • CRC Press

    (Publisher)

  2 Measurement Techniques in Micromachining Mohammad A. Younes Alexandria University, Alexandria, Egypt INTRODUCTION The last two decades have shown an ever-increasing interest in higher precision and miniaturization in a wide range of manufacturing activities. These growing trends have led to new requirements in machining, positioning control, and me-trology down to nanometer tolerances. Recent developments in silicon micromachining have made possible the fabrication of micromechanical elements of sizes typically ranging from 0.1 to 100 ,um [1-4]. Slots and apertures for some applications such as color TV, electron gun masks, and jet-engine turbines are made as small as 5 pm. Microcircuit elements of 0.5 to 1 pm are commonly manufactured using X-ray or electron-beam 15 16 Younes lithography [5]. In order to assess and control the quality of micromachined parts it has been necessary to develop new measuring techniques, capable of effectively and accurately measuring the dimensions, geometry, profile, and surface roughness of microholes, slots, very thin films, microspheres, steps, and grooves of different configurations in micromach- ined parts. These parts and features can be either checked for configuration and completeness, or measured to determine ac-tual sizes. Inspection and measurement of these features raise the demand for special equipment some of which depends on entirely new principles. 2.1 CLASSIFICATION OF MEASURING SYSTEMS In addition to high-resolution calipers and coordinate m easur-ing machines, equipment used for measurement of micro-machined parts includes high resolution microscopes, laser- based surface followers, scanning electron microscopes (SEM), interferometers, profilometers and scanning probes (e.g., scan-ning tunneling microscopes STM), and scanning force micro-scopes (SFM). The practical use of almost all these methods depends on the development of high-precision scanning tables as well as high-resolution linear transducers.

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