Vectors for Beginners

1921 ◽  
Vol 14 (7) ◽  
pp. 355-361
Author(s):  
Joseph B. Reynolds

The vector idea is so common in the study of science and the vector method so easy and effectual in application that students in preparatory schools should acquire an understanding of the subject. Its importance is emphasized when we recall that displacement, velocity, acceleration, force, electric cnrrent, stresses, strains and many other physical quantities can be correctly represented by vectors.

2020 ◽  
Vol 500 (3) ◽  
pp. 4110-4125
Author(s):  
Elliot M Lynch ◽  
Gordon I Ogilvie

ABSTRACT Whether tidal disruption events circularize or accrete directly as highly eccentric discs is the subject of current research and appears to depend sensitively on the disc thermodynamics. One aspect of this problem that has not received much attention is that a highly eccentric disc must have a strong, non-hydrostatic variation of the disc scale height around each orbit. As a complement to numerical simulations carried out by other groups, we investigate the dynamical structure of TDE discs using the non-linear theory of eccentric accretion discs. In particular, we study the variation of physical quantities around each elliptical orbit, taking into account the dynamical vertical structure, as well as viscous dissipation and radiative cooling. The solutions include a structure similar to the nozzle-like structure seen in simulations. We find evidence for the existence of the thermal instability in highly eccentric discs dominated by radiation pressure. For thermally stable solutions many of our models indicate a failure of the α-prescription for turbulent stresses. We discuss the consequences of our results for the structure of eccentric TDE discs.


2017 ◽  
Vol 84 (s1) ◽  
Author(s):  
Laura Mignanelli ◽  
Ilham Nashawati ◽  
Georg Bauer ◽  
Christian Rembe ◽  
Horst Krüsemann ◽  
...  

AbstractThe DMT (Deutschen Motorik Tests) investigate the current motor abilities, which are related to health and athletic physical activity, of children and youths. The aim of this work is the development of a suitable computer-controlled measuring station, which allows a simple and objective data collection of the performance of the kinesiology task of the balancing backward of the DMT. In this task, the child has to balance backward on three beams with different widths (6 cm, 4.5 cm and 3 cm) and a length of 3 m. The test starts on a board in front of the beam. The number of steps has to be counted till the subject touches the floor. The automated recording of measured values was investigated by various measuring methods, for example, acceleration, force sensors and gyroscopes . We propose a solution using the Kinect for Windows V2 for the data acquisition, which reduces personnel and time expenditure. We developed an algorithm to count the steps and to detect the floor contact, which leads to the end of the test.


1932 ◽  
Vol 25 (4) ◽  
pp. 212-214
Author(s):  
J. F. Phillipi

Having had in my classes in college algebra hundreds of students coming from a variety of preparatory schools, I have come to the conclusion that the subject of irrationals or radicals is a somewhat difficult subject and that any suggestion as to its presentation to students might be welcomed.


2017 ◽  
Vol 28 (17) ◽  
pp. 2317-2330 ◽  
Author(s):  
Carmine S Clemente ◽  
Abdelmomen Mahgoub ◽  
Daniele Davino ◽  
Ciro Visone

Kinetic energy harvesting devices based on magnetostrictive materials are composed of several parts, for dealing with multiphysics, including mechanical, magnetic, and electric quantities. An effective method to simulate the effects of different working conditions is important to fully exploit such devices. The aim of this paper is to present an equivalent circuit that can be identified with standard measurements on the device and simulated with a standard circuit simulator, such as Spice. The circuit is a nonlinear three-port circuit, related to the mechanical, magnetic, and electrical parts of the device. Unlike many of the published papers on the subject, the magneto-mechanical modeling is quite realistic and exploits nonlinear functions and the full coupling among the involved physical quantities of the employed magnetostrictive material. The nonlinear equivalent circuit is preliminarily validated on a concept device with permanent magnets biasing on a Stress Annealed Galfenol rod. Experimental data with different resistive loads and magnetic biasing are considered and compared with simulation outputs, in terms of the RMS voltage and harvested power.


2021 ◽  
Vol 4 ◽  
pp. 38-46
Author(s):  
Sergey Borisov ◽  

It should be noted that the current situation in Russia with regard to the socio-psychological adaptation of young people (age 17—25) to the changing digital environment does not find a proper theoretical and practical solution. Therefore, representatives of the socio-humanitarian sciences need their own methodology for measuring the adaptability of young people as the basis of their creative life. We believe that the key strategic line in the development of adaptability is to support of a young person formation as a subject of his own life. Despite the challenges of the times, the problem of adaptation in the aspect of subjectivity is limited to the spread of “myths” about the digital society and the declarative statements arising from them without a proper strategic and tactical scientific program. In this regard, the fundamental scientific result of our project will be developing, testing and evaluating the effectiveness of the methodology for measuring the socio-psychological adaptation of young people, developed on the basis of digital anthropology and metrology, which can be used as an interdisciplinary model of socio-humanitarian examination of subjectivity and adaptability. The assessment scale can be based on the idea of a standard (value, meaning), which form subjectivity, are formulated by the subject, determine the direction of his activity, his abilities, the project of his being. The model of this complex non-physical quantity can be represented through the concept of supervenience. Supervenience enables us to explain reductively through functional analysis. By explaining how functions are performed, we will explain the phenomenon. The cognitive model of subjectivity is such an abstractly causally organized system, the mechanisms of which are sufficient for implementing the corresponding functions. Then this model becomes logically possible, and, therefore, empirically confirmed (or refuted). Thus, it becomes possible to theoretically substantiate and experimentally prove that subjectivity is the basis of adaptability (strong option) or adaptability is closely related to subjectivity (weak option) and that for each type of adaptive activity the basis is a certain type of subjectivity. On the basis of this, an interdisciplinary model of socio-humanitarian examination of subjectivity and adaptability will be developed.


2011 ◽  
Vol 160 (2) ◽  
pp. 20-37
Author(s):  
Henryk ŁUKASIEWICZ

The use of sensors is the subject of research and heated discussions not only in our country. Through the creation of network centric warfare - NCW, the intensity of research about the use of sensors for military applications are on the increase. The use of sensors and sensor networks for the military forces must meet several requirements, which are not only related to their costs. These requirements are primarily associated with the reconnaissance possibilities of sensors, resistance to electromagnetic interference or with maintaining security of data transmission. This publication is the first from series of publications about sensors and sensors networks for military applications. Its purpose is to familiarize the reader with issues related to the construction of sensors as well as with the physical quantities measured by them.


PMLA ◽  
1965 ◽  
Vol 80 (3) ◽  
pp. 199-209 ◽  
Author(s):  
Hugh J. Luke

On 8 December 1824 Robert Southey sent to the editor of the Courier a long letter containing a final, post-mortem installment in his feud with Lord Byron. Reacting to some allusions to himself in Medwin's recently published Conversations of Lord Byron, Southey characteristically joined truculent self-defense with bitter and abusive attack:It was because Lord Byron had brought a stigma upon English literature [Southey explained] that I accused him; because he had perverted great talents to the worst purposes; because he had set up for pander-general to the youth of Great Britain as long as his writings should endure; because he had committed a high crime and misdemeanour against society, by sending forth a work in which mockery was mingled with horrors, filth with impiety, profligacy with sedition and slander. . . .Here I dismiss the subject. It might have been thought that Lord Byron had attained the last degree of disgrace when his head was set up for a sign at one of those preparatory schools for the brothel and the gallows, where obscenity, sedition, and blasphemy are retailed in drams for the vulgar. There remained one further shame,-there remained this exposure of his private conversations, which has compelled his lordship's friends ... to compare his oral declarations with his written words.


P.M. Harman, The scientific letters and papers of James Clerk Maxwell. Volume 1. 1846-1862 . Cambridge University Press, 1990. Pp. xxvii + 748, £125.00. ISBN 0-521-25625-9 James Clerk Maxwell (1831-1879) was arguably the most important British physicist in the latter half of the last century; a period in which there was some stiff competition from, for example, William Thomson (Lord Kelvin) and G.G. Stokes. With Darwin and Faraday he is among the men of science of the 19th century most widely admired by modern scientists. The reasons for this are not hard to find. His work had a lasting impact on physics and he pursued the subject both experimentally and mathematically in ways very similar to the methods of modern science: especially in the mathematical representation of physical quantities. Maxwell has been the subject of much scholarly study in recent years, but no scholarly biography of him has appeared or, so far as I am aware, is in progress. Furthermore, his immediate followers, the Maxwellians, have also been studied extensively. The lack of biography and concentration on followers might be taken to be a little curious except for the fact that a surprisingly small quantity of manuscript material has survived, for someone of his eminence. One of the reasons for this is obvious. His house, Glenlair, was destroyed by fire and it seems likely that much of his archive was consumed in the flames. However, the manuscript writings of any individual fall into two groups, those that are kept by the writer and those that are sent as letters to friends and colleagues. Here the fate of Maxwell’s manuscripts becomes more problematic. Of course those letters he wrote to his father and wife would most likely have been destroyed in the fire. But many of his letters to, for example, Stokes and Thomson, which should be in their archives, have simply disappeared, leaving no trace. Furthermore, much of his incoming correspondence has not survived, presumably because it too was destroyed in the fire.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1518
Author(s):  
Eulalia Balestrieri ◽  
Pasquale Daponte ◽  
Luca De Vito ◽  
Francesco Lamonaca

The advance of technology has enabled the development of unmanned systems/vehicles used in the air, on the ground or on/in the water. The application range for these systems is continuously increasing, and unmanned platforms continue to be the subject of numerous studies and research contributions. This paper deals with the role of sensors and measurements in ensuring that unmanned systems work properly, meet the requirements of the target application, provide and increase their navigation capabilities, and suitably monitor and gain information on several physical quantities in the environment around them. Unmanned system types and the critical environmental factors affecting their performance are discussed. The measurements that these kinds of vehicles can carry out are presented and discussed, while also describing the most frequently used on-board sensor technologies, as well as their advantages and limitations. The paper provides some examples of sensor specifications related to some current applications, as well as describing the recent research contributions in the field.


PMLA ◽  
1935 ◽  
Vol 50 (4) ◽  
pp. 1320-1327
Author(s):  
Colbert Searles

THE germ of that which follows came into being many years ago in the days of my youth as a university instructor and assistant professor. It was generated by the then quite outspoken attitude of colleagues in the “exact sciences”; the sciences of which the subject-matter can be exactly weighed and measured and the force of its movements mathematically demonstrated. They assured us that the study of languages and literature had little or nothing scientific about it because: “It had no domain of concrete fact in which to work.” Ergo, the scientific spirit was theirs by a stroke of “efficacious grace” as it were. Ours was at best only a kind of “sufficient grace,” pleasant and even necessary to have, but which could, by no means ensure a reception among the elected.


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