The Kinematic Synthesis of Toggle Clamps

1998 ◽  
Vol 120 (3) ◽  
pp. 648-655 ◽  
Author(s):  
Pei-Lum Tso
Keyword(s):  
Quadratic Equation ◽  
Function System ◽  
Implicit Function ◽  
Kinematic Synthesis ◽  
Mechanical Advantage ◽  
Function Generation ◽  
Different Types ◽  
Almost All ◽  
Generation Problem

The toggle clamp is one of the most common forms of clamps used throughout industry. They are commercially available in different types and models satisfying almost all ordinary fixture clamping requirements. Based on the theorem of implicit function system existence and the concept of solution plane, computers have been employed to generate planar four-bar mechanisms for three position function generation problem at the toggle positions. A quadratic equation which defines the locus can be plotted in the plane of solutions which have toggle at first, second, or third positions. Additionally this approach offers control over the mechanical advantage at clamping position, and defect free solutions. A vertical acting toggle clamp has been worked for illustrative purposes. This methodology has also been applied to generate slider-crank at toggle position for push-pull type toggle clamps.

Kinematic Synthesis of Geared Spherical Five Bar Mechanisms for Function Generation

1975 ◽  
Vol 97 (2) ◽  
pp. 723-730 ◽  
Author(s):  
D. L. Riddle ◽  
D. Tesar ◽  
J. Duffy
Keyword(s):  
Gear Train ◽  
Kinematic Synthesis ◽  
Design Procedures ◽  
Function Generation ◽  
Complete Formulation ◽  
Generation Problem

The synthesis of geared spherical five-bar mechanisms with application to the function generation problem is considered for multiply separated position specifications. Special gear train values reduce the geared five-bar to the elementary spherical four-bar. The planar four- and five-bar become a design subset to the spherical five-bar. Design procedures with complete formulation are outlined in detail.

Types of refractive errors and methods for their diagnosis

2020 ◽  
pp. 30-36
Author(s):  
Olga Lemzyakova
Keyword(s):  
Optical System ◽  
Contact Lenses ◽  
Vision Impairment ◽  
Refractive Errors ◽  
Vision Correction ◽  
Light Rays ◽  
Different Types ◽  
Almost All ◽  
Degrees Of Severity ◽  
The Brain

Refraction of the eye means its ability to bend (refract) light in its own optical system. In a normal state, which is called emmetropia, light rays passing through the optical system of the eye focus on the retina, from where the impulse is transmitted to the visual cortex of the brain and is analyzed there. A person sees equally well both in the distance and near in this situation. However, very often, refractive errors develop as a result of various types of influences. Myopia, or short-sightedness, occurs when the light rays are focused in front of the retina as a result of passing through the optical system of the eye. In this case, a person will clearly distinguish close objects and have difficulties in seeing distant objects. On the opposite side is development of farsightedness (hypermetropia), in which the focusing of light rays occurs behind the retina — such a person sees distant objects clearly, but outlines of closer objects are out of focus. Near vision impairment in old age is a natural process called presbyopia, it develops due to the lens thickening. Both myopia and hypermetropia can have different degrees of severity. The variant, when different refractive errors are observed in different eyes, is called anisometropia. In the same case, if different types of refraction are observed in the same eye, it is astigmatism, and most often it is a congenital pathology. Almost all of the above mentioned refractive errors require correction with spectacles or use of contact lenses. Recently, people are increasingly resorting to the methods of surgical vision correction.

XXVI.—The Field of the Essay

PMLA ◽  
1921 ◽  
Vol 36 (4) ◽  
pp. 551-564 ◽  
Author(s):  
Charles E. Whitmore
Keyword(s):  
Subject Matter ◽  
Actual Practice ◽  
Different Types ◽  
Almost All ◽  
Moderate Length

Of all the literary terms in common use, the word “essay” has perhaps the widest field and the most indeterminate content. Since the form to which it applies has taken on a fresh character in the hands of almost all its chief exponents, it has become in practice the designation for any piece of prose of moderate length, and has consequently embraced a bewilderingly various subject-matter. Moreover, the essayists themselves are by no means all of a piece. Bacon and Lamb, for instance, have little in common; and the type of ‘essayist’ represented by Macaulay and Carlyle has little in common with either. As a result of this wide extension, studies of the essay either include so much as to be very indefinite, or else are based on partial views, the upshot, in either case, becoming sufficiently vague. At the same time, the word “essay” goes on being used, and collections, of curiously assorted content, go on being made; and it therefore seems worth while to pass in review the different types represented in actual practice, in order to see just how much continuity is discernible among them.

Chromosomal instability in different species of agricultural animals (review)

2021 ◽  
pp. 19-26
Author(s):  
V. A. Andreeva
Keyword(s):  
Chromosomal Instability ◽  
Animal Species ◽  
Western Siberia ◽  
Reproductive Function ◽  
Farm Animals ◽  
Chromosomal Disorders ◽  
Important Indicator ◽  
Karyotypic Analysis ◽  
Different Types ◽  
Almost All

The purpose of the work was to analyze the frequency of chromosomal instability in different species of agricultural animals in Western Siberia on the basis of literature data. The analysis of the literature on the topic of somatic chromosomal instability in agricultural animals has been carried out. Despite the stability of the chromosome set, deviations from it are quite common. It is noteworthy that chromosomal instability is characteristic of almost all individuals in the population and serves as an important indicator for assessing the natural mutability of chromosomes. It has been found if an aberration appeared in one tissue, it is very likely to occur in others. It has been noted that somatic chromosomal instability occurs in animals with reduced reproductive function, as well as those suffering from any pathology. For example, in calves with parakeratosis the increase in the frequency of chromatid and isochromatid breaks has been found. Analysis of the frequency of aberrations in sires, which differ in the level of perinatal mortality of offspring revealed the increased percentage of offspring mortality in fathers with the large number of chromosomal disorders. Therefore, low fertilization, spontaneous abortions and stillbirths may be indications for karyotypic analysis. It has been revealed that the lability of the karyotype is inherent in all animal species, regardless of the species, sex and age, as well as the morphofunctional state. The data on some types of somatic chromosomal instability in different types of farm animals in Western Siberia has been presented. Such indicators as the frequency of polyploidy, the number of cells with fragments of chromosomes, as well as single and paired fragments of chromosomes has been given. Different types of chromosomal instability varied depending on the animal species and climate zone. The presented data can be accepted as a physiological norm and used in veterinary medicine and animal science.

Research Notes: Binary Test-Suites Using Covering Arrays

2018 ◽  
Vol 28 (09) ◽  
pp. 1321-1337 ◽  
Author(s):  
Jose Torres-Jimenez ◽  
Himer Avila-George ◽  
Ezra Federico Parra-González
Keyword(s):  
Software Testing ◽  
Test Generation ◽  
Software Systems ◽  
Combinatorial Testing ◽  
Covering Array ◽  
Covering Arrays ◽  
Almost All ◽  
Generation Problem ◽  
Test Suites

Software testing is an essential activity to ensure the quality of software systems. Combinatorial testing is a method that facilitates the software testing process; it is based on an empirical evidence where almost all faults in a software component are due to the interaction of very few parameters. The test generation problem for combinatorial testing can be represented as the construction of a matrix that has certain properties; typically this matrix is a covering array. Covering arrays have a small number of tests, in comparison with an exhaustive approach, and provide a level of interaction coverage among the parameters involved. This paper presents a repository that contains binary covering arrays involving many levels of interaction. Also, it discusses the importance of covering array repositories in the construction of better covering arrays. In most of the cases, the size of the covering arrays included in the repository reported here are the best upper bounds known, moreover, the files containing the matrices of these covering arrays are available to be downloaded. The final purpose of our Binary Covering Arrays Repository (BCAR) is to provide software testing practitioners the best-known binary test-suites.

scholarly journals DIFFERENT APPROACHES OF CLIENTS AND CONSULTANTS TO CONTRACTORS’ QUALIFICATION AND SELECTION

2005 ◽  
Vol 11 (4) ◽  
pp. 267-276 ◽  
Author(s):  
Mehmedali Egemen ◽  
Abdulrezak N. Mohamed
Keyword(s):  
Construction Industry ◽  
Selection Processes ◽  
Significant Difference ◽  
Different Types ◽  
Almost All ◽  
High Willingness

Nowadays, clients are the dominant groups in almost all types of industries. However, the construction industry is unique and consultants, as representatives of clients, are very important figures in this industry as well. By presenting survey findings of 91 clients and 50 consultants, this study reveals clients’ and consultants’ differing expectations of contracting organisations during contractor qualification and selection. The study has clearly confirmed the fact that consultants’ perspectives are rather different and their contractors’ expectations of their clients vary very significantly from the clients themselves. Furthermore, significantly different results were found even among different types of consultants and different categories of clients. Moreover, this study showed that both clients and consultants had high willingness to continue working with the same contractor in possible future works assuming they are satisfied with the previous works. The criteria, which contribute to achieving full client and/or consultant satisfaction and hence lead to possible repetitive works are identified and the results showed the existence of significant difference between clients and consultants perspectives regarding this issue as well. The framework presented within this paper aims to help the contracting organisations to compare and recognise the different approaches and perceptions of both clients and consultants during contractor qualification and selection processes. The contracting organisations in the related sectors will be able to use the framework provided within this study to recognise the overall demand in a more complete and better manner and hence formulate or modify strategies accordingly.

scholarly journals Evaluation of Possible Genotoxic Activity of Dirithromycin in Cultured Human Lymphocytes

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ahmet Kayraldız ◽  
Lale Dönbak ◽  
Ayşe Yavuz Kocaman ◽  
Esra Köker ◽  
Şule Gökçe
Keyword(s):  
Bacterial Infections ◽  
Human Lymphocytes ◽  
Sister Chromatid Exchanges ◽  
Mutagenic Action ◽  
Replication Index ◽  
Different Types ◽  
Nuclear Division Index ◽  
Almost All ◽  
Chromatid Exchanges

Dirithromycin antibiotic is a 14-membered lactone ring macrolide and is widely used in medicine to treat many different types of bacterial infections. In the present study, the possible genotoxicity of dirithromycin was evaluated in cultured human lymphocytes by using sister chromatid exchanges (SCEs), chromosome aberration (CA), and micronucleus (MN) tests and also cell proliferation kinetics such as mitotic index (MI), replication index (RI), and nuclear division index (NDI) were analyzed for cytotoxicity. Cell cultures were treated with four different concentrations of dirithromycin (37.75, 67.50, 125, and 250 µg/mL) for 24 and 48 h periods. Dirithromycin significantly induced SCE and MN frequency at all concentrations in both 24 and 48 h treated cells. In addition, CA level has been markedly increased in the cells treated with almost all concentrations of dirithromycin for 24 (except 37.75 µg/mL) and 48 h treatment periods as compared to control. However, MI, RI, and NDI values were not affected by the dirithromycin treatment (p> 0.05). The results of this study indicated that dirithromycin treatment caused genetic damage by increasing the level of cytogenetic endpoints, suggesting its genotoxic and mutagenic action on human lymphocytesin vitro.

Multiply Separated Synthesis of Six-Link Mechanisms Using Parallel Homotopy With M-Homogenization

1998 ◽  
Author(s):  
A. K. Dhingra ◽  
M. Zhang
Keyword(s):  
Group Theory ◽  
Matrix Method ◽  
Parallel Implementation ◽  
Homotopy Methods ◽  
Numerical Work ◽  
Function Generation ◽  
Connection Machine ◽  
The Matrix ◽  
Generation Problem ◽  
Complete Solutions

Abstract This paper presents complete solutions to the function generation problem of six-link Watt and Stephenson mechanisms, with multiply separated precision positions (PP), using homotopy methods with m-homogenization. It is seen that using the matrix method for synthesis, applying m-homogeneous group theory and by defining auxiliary equations in addition to the synthesis equations, the number of homotopy paths to be tracked in obtaining all possible solutions to the synthesis problem can be drastically reduced. Numerical work dealing with the synthesis of Watt and Stephenson mechanisms for 6 and 9 multiply separated precision points is presented. For both mechanisms, it is seen that complete solutions for 6 and 9 precision points can be obtained by tracking 640 and 286,720 paths, respectively. A parallel implementation of homotopy methods on the Connection Machine on which several thousand homotopy paths can be tracked concurrently is also discussed.

scholarly journals Comparing the host galaxies of different type supernovae

2015 ◽  
Vol 11 (S319) ◽  
pp. 139-139
Author(s):  
Y. C. Liang ◽  
X. Shao ◽  
M. Dennefeld ◽  
X. Y. Chen ◽  
L. Zhou ◽  
...  
Keyword(s):  
Stellar Mass ◽  
Significant Fraction ◽  
Host Galaxies ◽  
Global Properties ◽  
Different Types ◽  
Type Ia ◽  
Total Light ◽  
Stellar Masses ◽  
Almost All ◽  
Cross Matching

AbstractWe compare the host galaxies of 902 supernovae, including Type Ia, II and Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the SDSS DR7. We further selected 213 galaxies by requiring the light fraction of spectral observations > 15%, which could represent well the global properties of the galaxies. The diagrams related to Dn(4000), HδA, stellar masses, SFRs and specific SFRs for the SNe hosts show that almost all SNe II and most of SNe Ibc occur in SF galaxies. A significant fraction of SNe Ia occurs in AGNs and Absorp galaxies. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures < 15% of the total light. These comparison galaxies appear biased towards higher 12+log(O/H) (~0.1dex) at a given stellar mass, suggesting the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

Most Speculative Attacks Do Not Succeed: Currency Crises and Currency Crashes

2018 ◽  
Vol 09 (01n02) ◽  
pp. 1850001 ◽  
Author(s):  
Hassan Almahmood ◽  
Munif Al Munyif ◽  
Thomas D. Willett
Keyword(s):  
Exchange Rates ◽  
Interest Rates ◽  
Currency Crises ◽  
Emerging Market ◽  
Exchange Market ◽  
Speculative Attacks ◽  
Considerable Research ◽  
Different Types ◽  
Almost All ◽  
Market Pressure

While there has been considerable research on currency crises, relatively little attention has been given to whether they are successful or not. We investigate this question for a set of 32 emerging market economies for the period 1980–2014. In the literature, many different measures of currency crises have been used, but almost all use some variants of exchange market pressure indices that look at changes in exchange rates, international reserves, and often also interest rates. These vary mainly in their specific specifications such as how to weigh the different variables. Therefore, to check the robustness of our results we use six different specifications. A second type of measure is also sometimes used. These focus only on large depreciations of exchange rates. While often called measures of currency crises they are really only measures of currency crashes. We thus take this approach as a measure of successful attacks. Using a wider range of thresholds than studies such as Lavean and Valencia’s, a well-known dataset of different types of financial crises, we still find that the vast majority of speculative attacks are not successful.

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