Spiral Power Springs. Part 2—Design

1971 ◽  
Vol 93 (2) ◽  
pp. 676-682 ◽  
Author(s):  
C. A. Queener ◽  
G. E. Wood
Keyword(s):  
Theoretical Model ◽  
Shape Factor ◽  
Empirical Equation ◽  
Logarithmic Spiral ◽  
Companion Paper ◽  
Theoretical Equation ◽  
Extended Model ◽  
Practical Application ◽  
Good Accord ◽  
Frictional Hysteresis

The theoretical model developed in a preceding companion paper for predicting the torque-turn behavior of a spiral power spring is extended in an effort to improve the practical applicability. A theoretical equation based on springback theory is developed for computing the shape factor in the logarithmic spiral and an empirical equation for calculating the magnitude of frictional hysteresis is obtained. The extended model is tested with two springs and the experimental and calculated results are in good accord. The computation procedure involved in practical application of the extended model for spring design is discussed.

scholarly journals The viscosity of strong electrolytes measured by a differential method

1934 ◽  
Vol 145 (855) ◽  
pp. 475-488 ◽  
Keyword(s):  
Dielectric Constant ◽  
Empirical Equation ◽  
Relative Viscosity ◽  
Absolute Temperature ◽  
Differential Method ◽  
Theoretical Equation ◽  
Electronic Charge ◽  
Accurate Data ◽  
Avogadro’S Number ◽  
Strong Electrolytes

Until quite recently no satisfactory equation had been obtained for the representation of the viscosity of dilute solutions of strong electrolytes. An empirical equation was recently proposed by Jones and Dole to fit the only accurate data then available. Their equation may be represented thus : η = 1 + A √ c + B c , η = relative viscosity of the solution c = concentration in moles per litre A and B are constants. Jones and Dole realized that the coefficient A is due to interionic forces and in a series of later publications Falkenhagen, Dole and Vernon have deduced a theoretical equation giving values of A in terms of well-known physical constants. Their complete equation may be written η = 1 + ε √N v 1 z 1 /30η 0 √1000D k T ( z 1 + z 2 ) 4 π × [¼ μ 1 z 2 + μ 2 z 1 / μ 1 μ 2 - z 1 z 2 (μ 1 - μ 2 ) 2 /μ 1 μ 2 (√μ 1 z 1 + μ 2 z 2 + √(μ 1 + μ 2 ) ( z 1 + z 2 ) ) 2 ]√ c , where N = Avogadro's number v 1 , v 2 = numbers of ions z 1 , z 2 = valencies of ions μ 1 , μ 2 = absolute mobilities of ions D = dielectric constant of solvent k = Boltzmann's constant ε = electronic charge η 0 = viscosity of solvent T = absolute temperature.

THEORETICAL DEFINITIONS FOR AUXILIARY CONCEPTS OF VARIOUS LEVELS OF ABSTRACTION

2020 ◽  
pp. 28-31
Author(s):  
Valentin Karpovich
Keyword(s):  
Theoretical Model ◽  
Subject Area ◽  
Theoretical Concept ◽  
Theoretical Knowledge ◽  
Practical Application ◽  
Levels Of Abstraction ◽  
Theoretical Concepts ◽  
The Subject ◽  
Logical Constraints

Theoretical knowledge may contain various levels of abstraction represented by logical constructions from the observed characteristics of objects from the subject area of the theory. The degree of abstractness can be de-scribed by the complexity of the structures obtained from the initial observational terms. Such auxiliary construc-tions are characterized as explicit or implicitdefinitions of theoretical concepts in terms of observational. One of the techniques for constructing such definitions is the operationalization of abstractions by a system of reduction sentences. In this case a theoretical concept is characterized as “open” and plays a role of logical and methodo-logical constraints for expanding the possible connections of the theoretical model with the help of concepts from the domain of intended practical application.

Assessment and Meta-Assessment

2019 ◽  
pp. 233-255 ◽  
Author(s):  
Nina Birnaz ◽  
Valeria Botezatu
Keyword(s):  
Higher Education ◽  
Theoretical Model ◽  
Formative Assessment ◽  
Training Program ◽  
Learning Process ◽  
Classical Model ◽  
Research Problem ◽  
Extended Model ◽  
Measurement Feedback ◽  
Assessment In Higher Education

This chapter describes the theoretical model of ecodesign of formative assessment in higher education. In this context, the formative assessment is the technology of measurement, feedback, and appreciation that guides the training of teachers' professional competences throughout their lives. The basic idea reflected in the chapter starts from the assumption that the teacher, the student, and the content are co-participants in the learning process, the maintenance of the process being assured by communication with feedback. The chapter consists of three sections. The first section describes the differences between the classical model and the extended model of formative assessment, the latest definitions of formative assessment, meta-assessment, and ecodesign. In the second section are presented the contradictions on the basis of which the research problem is established. The chapter ends with the theoretical model of the ecosystem of the formative assessment based on the instructional dynamic and flexible strategy and also with the training program of formative assessment competence.

Achieving a Working Balance Between Technology and Personal Contact Within a Classroom Environment

2011 ◽  
pp. 212-226
Author(s):  
Stephen Springer
Keyword(s):  
Distance Learning ◽  
Theoretical Model ◽  
Faculty Member ◽  
Classroom Environment ◽  
Faculty Members ◽  
Personal Contact ◽  
Practical Application ◽  
Human Relations ◽  
Exchange Of Information ◽  
Counseling Theory

This chapter addresses the author’s model to assist faculty members in gaining a closer relationship with distance learning students. The model that will be discussed consists of a greeting, message, reminder, and conclusion (GMRC). The GMRC will provide concrete recommendations designed to lead the faculty through the four steps. Using these steps in writing and responding to electronic messages demonstrates to the distance learning student that in fact the faculty member is concerned with each learner and the learner’s specific questions and needs. It is a practical application of human relations theory and is based on ideas generated by counseling theory. In addition, the chapter will take the reader through issues and examples that will arise during the duration of discussions and exchange of information using electronic messages. It is the intent of the author to provide not simply a theoretical model, but a model that can be learned and applied immediately upon completion of reviewing the article.

scholarly journals Growth and distribution endogenously determined: a theoretical model and empirical evidence

2019 ◽  
Vol 39 (2) ◽  
pp. 344-361
Author(s):  
HERNÁN BORRERO ◽  
NESTOR GARZA
Keyword(s):  
Theoretical Model ◽  
Latin American ◽  
Empirical Literature ◽  
Growth Theory ◽  
Extended Model ◽  
Aggregate Production ◽  
Long Run ◽  
Aggregate Production Function ◽  
Asset Distribution ◽  
Latin American Countries

ABSTRACT We build upon an already known but scarcely developed feature of growth theory: the importance of asset distribution in an aggregate production function. We elaborate on a simple model of two individuals, and then generalize its deductions to an extended model of n agents, concluding that perfectly distributed productive capital leads to positive and optimum long-run “endogenous” growth. Recent and classical empirical literature on the topic suggests this interpretation. In addition, we find exploratory panel data evidence that supports our theory of growth and distribution in a set of Latin American countries.

THE VISCOSITY OF VINYL ACETATE

1937 ◽  
Vol 15b (1) ◽  
pp. 7-12 ◽  
Author(s):  
D. O. White ◽  
A. C. Cuthbertson
Keyword(s):  
Vinyl Acetate ◽  
Latent Heat ◽  
Characteristic Frequency ◽  
Empirical Equation ◽  
Theoretical Equation ◽  
Heat Of Evaporation

The viscosity of monomeric vinyl acetate has been measured over a range of temperatures from 0° to 60 °C. Two equations were obtained which represent the results. The empirical equation is [Formula: see text], and a theoretical equation is given as [Formula: see text]. The characteristic frequency has been obtained from the relation [Formula: see text], where μ is the ratio between the latent heat of evaporation and the heat of cohesion, v was found to be 2.17 × 1012.

scholarly journals Perfecting the Advanced 2D Multi-electrode Electrical Exploration method

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Minh Vũ
Keyword(s):  
Theoretical Model ◽  
Practical Application ◽  
Array Data ◽  
Data Collecting ◽  
Electrical Sounding

The Advanced Multi-electrode Electrical Sounding method (AMES) proposed by us was introduced at VNU. Journal of Mathematics-Physics, No. 31 (3), 2015. However, the published results are mostly focused on the symmetric MC array and tested on a theoretical model. In this paper, the authors continue systematically presenting and supplementing the results obtained after the study, namely the finalization and renaming of the AMES method into the Advanced 2D Multi-electrode Electrical Exploration (AMEE) method, including MC array, data collecting and processing, and testing on theoretical model and practical application  to confirm the superiority of this method.

scholarly journals A Microfluidic Rotational Motor Driven by Circular Vibrations

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 809 ◽  
Author(s):  
Suzana Uran ◽  
Božidar Bratina ◽  
Riko Šafarič
Keyword(s):  
Theoretical Model ◽  
Piezoelectric Actuator ◽  
Rotational Speed ◽  
Water Droplet ◽  
Low Frequency ◽  
Piezoelectric Actuators ◽  
Frequency Region ◽  
Practical Application ◽  
3D Printed ◽  
Electro Wetting

Constructing micro-sized machines always involves the problem of how to bring the energy (electric, magnetic, light, electro wetting, vibrational, etc.) source to the device to produce mechanical movements. The paper presents a rotational micro-sized motor (the diameter of the rotor is 350 µm) driven by low frequency (200–700 Hz) circular vibrations, made by two piezoelectric actuators, through the medium of a water droplet with diameter of 1 mm (volume 3.6 µL). The theoretical model presents how to produce the circular streaming (rotation) of the liquid around an infinitely long pillar with micro-sized diameter. The practical application has been focused to make a time-stable circular stream of the medium around the finite long vibrated pillar with diameter of 80 µm in the presence of disturbances produced by the vibrated plate where the pillar is placed. Only the time-stable circular stream in the water droplet around the pillar produces enough energy to rotate the micro-sized rotor. The rotational speed of the rotor is controlled in both directions from −20 rad/s to +26 rad/s. 3D printed mechanical amplifiers of vibrations, driven by piezoelectric actuators, amplify the amplitude of the piezoelectric actuator up to 20 µm in the frequency region of 200 to 700 Hz.

Analysis of Tire Performance on Sand

1995 ◽  
Vol 23 (1) ◽  
pp. 52-67 ◽  
Author(s):  
H. Ataka ◽  
F. Yamashita
Keyword(s):  
Empirical Equation ◽  
Theoretical Equation ◽  
Shearing Stress ◽  
Propulsive Force ◽  
Breaking Force ◽  
Measuring Techniques ◽  
The World ◽  
Precise Prediction ◽  
The Difference

Abstract Recently, vehicles on sand have been operated at higher speeds with diversified usage, and requests for the development of radial tires, applicable to both pavements and sandy areas have emerged. Although a large number of studies and analyses of tire performance on paved surfaces have been reported, few reports are available for tire performance on sandy surfaces. This study deals with the behavior of radial tires on the sand. A simple theoretical equation was derived in which the sand traction performance could be expressed as the difference between the propulsive force and the driving resistance on sand. The theoretical equation was found to be highly related to the empirical equation derived from previous work. Sand samples from typical deserts were used for analyses of shearing stress and compressive breaking force of sand through unique measuring techniques, resulting in modification of the theoretical equation to give more precise prediction of the tire performance on sand for most areas in the world.

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