Equal Arm Balance Research Articles

An Evaluation of a Bronze Pan with the Inscription BANNAF in the Pera Museum

The Collection of Anatolian Weights and Measures of the Suna and İnan Kıraç Foundation Pera Museum has an extensive selection of objects that provides information about the economic, social, and cultural life in Anatolia, Mesopotamia, and the Mediterranean regions. Part of the collection consists of equal arm balance scales and equipment of these scales. In this article, a bronze object from the collection, a scale pan dating back to the Roman period, is evaluated. This previously unpublished object is compared to other known examples of similar pans to determine its function, date the object, and examine the stamp on the pan. Since this object is the only known example of pans with BANNAF inscriptions in Turkish museums, it will greatly contribute to the understanding of pans with BANNAF inscriptions that will appear in future archaeological studies and museum research in Türkiye.

Measurement of the Sensitivity for Diving-bell Manometer

Diving-bell manometers are devices mainly used for low-gauge measurements, with a variety of industrial and medical applications. At the Colombian <em>Instituto Nacional de Metrología</em>, a Junkalor Dessau TMG 25/1104 diving-bell manometer was subjected to sensitivity verification, with 200 mg as the discrimination threshold. Considering that this manometer works analogously to an equal arm balance, sensitivity is defined as the weight change on the balance that is needed to produce a movement larger that the smallest estimable fraction of a scale interval determined by visual interpolation component (resolution on the indicator element). Three set data points were evaluated: the first, with 20 g placed on each plate; the second, with 19.7 g on the left plate and 20 g placed on the right plate; and the third, with 20.3 g on the left plate and 20 g on the right plate. Recommendations for use of the diving bell are made and the resolution for the device was determined.

Mass metrology-after 4000 years, a change is coming

The basics of mass metrology have their roots in prehistory. Evidence can be seen in a set of typical Bronze Age weights from the Indus Valley in the collection of the Museum of Fine Arts in Boston, MA (Fig. 1). The civilization flourished until about 1900 B.C.E. The weights are well-crafted stone cubes. The smallest unit is about 0.86 g. Besides being well made, the sizes of many of the weights are in a binary series. Perhaps one of the weights designated “16” was taken to be the standard. Other “16” weights could then be manufactured to be the same by comparing them on an equal-arm balance. A “32” weight could be made equal to two “16” weights. Two “8” weights would be made equal to each other, and their sum equal to a “16” weight—again calling on the services of an equal-arm balance. Exactly the same principle was still used millennia later in much of Europe in the form of nested cups (Fig. 2). When all elements are nested together, the mass in this example is one Spanish pound, or sixteen ounces. Such weight sets were still in use two centuries ago. The most famous weights of this type were manufactured in Nuremburg; and prior to 1799, the primary mass standard of France had the form of nested weights. For thousands of years, the game has been to improve balance design, improve the objects used as mass standards, and, much more recently, to understand mass metrology in a wider context of physical measurements.

Calibration: A Conceptual Framework Applied to Scientific Practices Which Investigate Natural Phenomena by Means of Standardized Instruments

This paper deals with calibration in scientific practices which investigate relatively well-understood natural phenomena by means of already standardized instrumental devices. Calibration is a crucial topic, since it conditions the reliability of instrumental procedures in science. Yet although important, calibration is a relatively neglected topic. We think more attention should be devoted to calibration. The paper attempts to take a step in this direction. The aims are two-fold: (1) to characterize calibration in a relatively simple kind of scientific practices; (2) to provide conceptual and taxonomic tools of broader scope that help to get a better understanding of calibration in more complex cases and other kinds of scientific practices. For this purpose, we first provide indications for why a conceptual framework is needed. Second, a bibliographic survey of works dealing with calibration is attempted. Third, we introduce different tools to enable a better understanding of calibration. Fourth, we turn to the elaboration of what we call a “simple exemplar” of calibration, illustrated through the case of the calibration of an equal-arm balance. Fifth, the tools previously introduced, and the framework of the simple exemplar, are applied to a more complex case of calibration: calibration procedures in X-ray experiments. This serves to show the work accomplished by the simple exemplar and to emphasize features of more complex cases of calibration. Eventually, we revisit and specify the nature, status, scope and value of the proposed framework.

Automating Data Acquisition on a Mechanical Equal-Arm Balance Used in Large Mass Calibrations

This paper focuses on efforts by the Mass and Force Group at the National Institute of Standards and Technology (NIST) to enhance the data taking operations of an approximately 40 year-old mechanic...

The Science of Weights in Ancient Sri Lanka: A Study based on Equal Arm Balance from Alahana Pirivena, Polonnaruwa.

"ENGINEER", established in 1973 by The Institution of Engineers, is a Journal for dissemination of Engineering knowledge, published quarterly.If you are interested in contributing an Original Technical Paper based on research by the author(s) (intended for Section I) or an Original Article of Professional or Technical interest related to Engineering. (Section II) to this journal please go through the publication checklist which can be downloaded from here.Cover DescriptionCover images show a few views of 5000 DWT Misje Vita built by Colombo Dockyard PLC.

A NEW SCHEME TO REALIZE THE MEASUREMENT STANDARD OF MICROFORCE

To increase the accuracy of mechanical characterizations of microstructures and nanomaterials on the molecular- and nano-scale, the measurement standard of microforce ranging from 10-6 N to 10-9 N must be realized for calibrating the testing and measuring instruments. In this paper, a new scheme based on the equal-arm torsion balance is proposed. This precision torsion balance detects accurately the gravitational force between two mass standards, and links the small force measurement to the International System of Units and Newtonian gravitational constant G. Such a balance might serve as a force standard machine operating in the regime below 10-6 N with an accuracy of 0.1%.

Basic features in primary-standard equal-arm balances

Basic features in primary-standard equal-arm balances

A high precision method for comparing large masses using load cells

Describes a method of comparing large masses using commercial load cells. The results were recorded and analyzed using a microcomputer. The tests described show that deadweight machine masses of 2 tonnes can be compared with an uncertainty of 1 PPM using equipment generally available in a force standards laboratory. Further tests using an overhead gantry crane show that large masses can be compared with an uncertainty better than 5 PPM under less ideal conditions. The results indicate that the method would be useful for the verification of large masses and provide an alternative to the use of either equal arm balances, or mass comparators based on the use of load cells under constant load.

A 1 kg Mass Comparator Using Flexure-Strip Suspensions: Preliminary Results

This paper describes the design and construction of a novel form of equal-arm balance. The balance has been designed to study the performance of flexure strips for use as pivots in a 1 kg mass comparator working at the highest accuracy. The beam of the balance is servo controlled using optical detection of angular position and electromagnetic control. Small mass differences are measured in terms of the differences in the servo currents required to reproduce the same position of the beam. Preliminary results using this prototype balance indicate that an accuracy in mass comparison of about 5 parts in 1010 can be achieved.

Measuring mass with the equal-arm balance

First Page

New method for testing and adjusting equal-arm balances by the period of their oscillations

The suggested technique serves to evaluate the distance from the center of gravity of the beam to its oscillation axis and the gap between the knife-edge bearings for a given load on the beam by measuring two oscillation periods of the beam and one oscillation period of the balance for a given load and determining the moment of inertia of the beam with respect to its oscillation axis. Having determined the gaps between the bearings for several loads, it is possible to evaluate the deformations of the beam and of the knife edges under the load. The sought for values of I, c, and m are determined, in this method of investigating equal-arm balances, by means of elementary calculations from simple formulas which do not require a large expenditure of labor or time, or the participation of highly-qualified operators.

Double knife-edge (single-arm) balances

The testing of the type OVM balance experimental models has shown that their technical characteristics correspond to those of similar balances produced by foreign firms, including the Mettler Company. The type OVM balances have better metrological characteristics than equal-arm balances (for the same maximum loads), and they are at the same time more efficient and convenient to use and, therefore, there can be no doubt that they will be widely used in various fields of science and technology, and, above all, in chemistry for precision analyses and other precision weighing. These balances can also be used for certifying and testing weights of the second and third classes and reference weights of the second and third grades either by means of the calibration method or direct comparison. Moreover, the grade 3 and class 3 reference weights can be tested against the weights incorporated in the balance by taking their nominal mass values.

Experimental Deduction of the Law of Centripetal Force

A simple laboratory experiment using a pendulum suspended from an equal-arm balance is capable of furnishing data from which the form of the equation for centripetal force may be deduced.

On various versions of the defective coin problem

The problem of ascertaining the minimum number of weighings which suffice to determine the defective coin in a set of N coins of the same appearance, given an equal arm balance and the information that there is precisely one defective coin present, is well known. A large number of ingenious solutions exist, some based upon sequential procedures and some not. The problem in the case where there are known to be two or more defective coins is far more complex because we cannot draw any simple definite conclusions at the end of a single test. We shall analyze this in detail in the following paper. The purpose of this paper is to indicate a systematic way in which the theory of dynamic programming can be used to provide a computational solution to the determination of optimal and suboptimal testing policies. We shall illustrate this by means of some numerical results obtained using a digital computer.

Inertial Equal Arm Balance with Thyristor Indicator Circuit

First Page

Effect of specific load on the variation in reading of an equal-arm balance

Effect of specific load on the variation in reading of an equal-arm balance

The Equal Arm Balance

The Equal Arm Balance