Optimum design of gripper jaws for tapered components

Robotica ◽  
1990 ◽  
Vol 8 (3) ◽  
pp. 223-230 ◽  
Author(s):  
D.T. Pham ◽  
M.J. Nategh
Keyword(s):  
Optimum Design ◽  
Three Dimensional ◽  
Taper Angle ◽  
Planar Curves ◽  
Optimum Selection ◽  
Wide Range ◽  
Different Diameters ◽  
Selection Of

SUMMARYFor ease of manufacture, axisymmetric components produced by processes such as forging, casting and moulding are often designed with a taper angle. This paper presents a family of devices for handling such components by their tapered portion. The devices are essentially finger tips, or jaws, to be fitted to standard scissor-type robot grippers. The jaws possess a three-dimensional profile constructed as a stack of v-shaped planar curves. The special jaw profile enables components of different diameters and taper angles to be gripped concentrically without calling for complex movements to reposition the gripper. The equations describing two categories of profile are derived and the optimum selection of profile parameters to yield compact jaws to grip components of a wide range of dimensions is discussed in the paper.

Model studies of electrical leak detection surveys in geomembrane‐lined impoundments

Geophysics ◽  
1988 ◽  
Vol 53 (11) ◽  
pp. 1453-1458 ◽  
Author(s):  
J. O. Parra ◽  
T. E. Owen
Keyword(s):  
Field Survey ◽  
Electrical Potential ◽  
Three Dimensional ◽  
Liquid Waste ◽  
Finite Size ◽  
Leak Detection ◽  
Electrode Spacing ◽  
Model Studies ◽  
Optimum Selection ◽  
Selection Of

Pole‐dipole array electrical potential distributions are calculated for a geomembrane‐lined liquid impoundment having single or multiple leaks. A three‐dimensional numerical model is employed to represent a small circular leak in the highly resistive plastic liner. The liquid waste material, the liner, and the soil under the impoundment are simulated by infinite horizontal layers, with approximate corrections for the finite size of the impoundment. Parametric curves for a single leak show that with optimum selection of electrode spacing and positioning and other field survey parameters, leaks can be detected effectively. To identify and resolve the presence of a cluster of leaks, the potential measurements must be made close to the liner and the detector dipole spacing must be smaller than the separation of the leaks. The results also indicate that the survey speed may be increased when portable leak detection equipment employing a vertical dipole detector is used.

scholarly journals An experimental study of the motion of a viscous liquid contained between two coaxial cylinders

1928 ◽  
Vol 117 (777) ◽  
pp. 388-407 ◽  
Keyword(s):  
Viscous Liquid ◽  
Three Dimensional ◽  
Critical Value ◽  
Limited Range ◽  
Axial Plane ◽  
Stream Line ◽  
Coaxial Cylinders ◽  
Wide Range ◽  
The Stability ◽  
Different Diameters

The stability of a viscous liquid contained between two coaxial cylinders which are capable of independent rotation has been investigated by G. I. Taylor. At low speeds of rotation the motion of the liquid is two-dimensional, each particle of liquid rotating in a circle concentric with the cylinders. This type of motion is possible whether the cylinders rotate in the same or in opposite directions, and is stable for velocities of the inner cylinder not exceeding a certain critical value. At the critical speed the laminar motion is succeeded by a three-dimensional motion, such that the circulation of the liquid is confined to a scries of annular compartments, one above the other. When both cylinders rotate in the same direction, the height of each compartment equals the distance between the cylinders, and the motion in an axial plane appears to consist of a series of vortices in square compartments, adjacent vortices rotating in opposite directions. For cylinders rotating in opposite directions there are, at a given horizontal level, two annular compartments side by side and concentric with the cylinders. In this case, the circulation in an axial plane appears to consist of two series of vortices, adjacent vortices both vertically and horizontally rotating in opposite directions. By using coloured liquid filaments to follow the motion, Taylor verified experimentally, within a limited range, the expression for the critical velocity at which the stream-line motion becomes unstable and certain other points. The apparatus used was large and robust, the length of the cylinders being 90 cm., and it was unsuitable for investigating the motion under varying conditions, such as with inner cylinders of different diameters and with liquids giving a wide range in viscosity.

scholarly journals Methodological support for the training of UAV designers and operators

2021 ◽  
Vol 20 (1) ◽  
pp. 14-28
Author(s):  
O. E. Lukyanov ◽  
D. V. Zolotov
Keyword(s):  
Geometric Model ◽  
Three Dimensional ◽  
Calculated Data ◽  
Mutual Effect ◽  
Blade Element Theory ◽  
Wide Range ◽  
Initial Control ◽  
Training And Research ◽  
Aircraft Type ◽  
Selection Of

In this paper, we presented the developed concept for end-to-end training of designers and operators of UAVs on the basis of the use of specialized aircraft-type trainers. The educational possibilities of the concept in terms of various training programs are discussed. A methodology for the selection of the main parameters of UAV taking into account the mutual effect of aerodynamics and weight was developed. It provided a wide range of specific requirements for UAVs for acquiring initial control skills in manual and automatic modes. The developed methodology is based on the takeoff-weight buildup equation modified with regard to the specific requirements for small-sized vehicles. This methodology also includes the process of choosing the most advantageous combination of geometric and kinematic parameters of an aircraft propeller using the isolated blade element theory. The methodology is implemented in PascalABC.NET language. A demonstrative example of selecting the main parameters of a training UAV for specific requirements is presented. The obtained basic technical characteristics of the UAV are given. A three-dimensional geometric model of the UAV was developed on the basis of the calculated data, and a prototype was manufactured. The flight parameters recorded through a series of test flights of the prototype are presented. The ways of using the described methodology for the development of training-and-research UAVs are discussed.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

Synthesis, Characterization and Antiproliferative Activity Assessment of a Novel 1H-5-mercapto-1,2,4 Triazole Derivative

2017 ◽  
Vol 68 (4) ◽  
pp. 745-747 ◽  
Author(s):  
Marius Mioc ◽  
Sorin Avram ◽  
Vasile Bercean ◽  
Mihaela Balan Porcarasu ◽  
Codruta Soica ◽  
...  
Keyword(s):  
Antiproliferative Activity ◽  
Biological Activities ◽  
Cancer Cell Line ◽  
Vascular Endothelial ◽  
Triazole Derivative ◽  
Activity Assessment ◽  
Wide Range ◽  
Specific Receptors ◽  
Endothelial Growth Factor ◽  
Selection Of

Angiogenesis plays an important function in tumor proliferation, one of the main angiogenic promoters being the vascular endothelial growth factor (VEGF) which activates specific receptors, particularly VEGFR-2. Thus, VEGFR-2 has become an essential therapeutic target in the development of new antitumor drugs. 1,2,4-triazoles show a wide range of biological activities, including antitumor effect, which was documented by numerous reports. In the current study the selection of 5-mercapto-1,2,4-triazole structure (1H-3-styryl-5-benzylidenehydrazino-carbonyl-methylsulfanil-1,2,4-triazole, Tz3a.7) was conducted based on molecular docking that emphasized it as suitable ligand for VEGFR-2 and EGFR1 receptors. Compound Tz3a.7 was synthesized and physicochemically and biologically evaluated thus revealing a moderate antiproliferative activity against breast cancer cell line MDA-MB-231.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

scholarly journals A Virtual Telescope for the Open University Science Foundation Course

1998 ◽  
Vol 162 ◽  
pp. 100-105
Author(s):  
Andrew J. Norton ◽  
Mark H. Jones
Keyword(s):  
Social Science ◽  
Open University ◽  
Distance Teaching ◽  
The Arts ◽  
Wide Range ◽  
University Science ◽  
First Time ◽  
Degree Level ◽  
Selection Of

The Open University is the UK's foremost distance teaching university. For over twenty five years we have been presenting courses to students spanning a wide range of degree level and vocational subjects. Since we have no pre-requisites for entry, a major component of our course profile is a selection of foundation courses comprising one each in the Arts, Social Science, Mathematics, Technology and Science faculties. The Science Faculty's foundation course is currently undergoing a substantial revision. The new course, entitled “S103: Discovering Science”, will be presented to students for the first time in 1998.

scholarly journals Organelle Genetics in Plants

2021 ◽  
Vol 22 (4) ◽  
pp. 2104
Author(s):  
Pedro Robles ◽  
Víctor Quesada
Keyword(s):  
Rna Editing ◽  
Posttranscriptional Regulation ◽  
Genome Engineering ◽  
Plant Mitochondria ◽  
Plastid Dna ◽  
Chloroplast Genomes ◽  
Wide Range ◽  
Organelle Genetics ◽  
Selection Of

Eleven published articles (4 reviews, 7 research papers) are collected in the Special Issue entitled “Organelle Genetics in Plants.” This selection of papers covers a wide range of topics related to chloroplasts and plant mitochondria research: (i) organellar gene expression (OGE) and, more specifically, chloroplast RNA editing in soybean, mitochondria RNA editing, and intron splicing in soybean during nodulation, as well as the study of the roles of transcriptional and posttranscriptional regulation of OGE in plant adaptation to environmental stress; (ii) analysis of the nuclear integrants of mitochondrial DNA (NUMTs) or plastid DNA (NUPTs); (iii) sequencing and characterization of mitochondrial and chloroplast genomes; (iv) recent advances in plastid genome engineering. Here we summarize the main findings of these works, which represent the latest research on the genetics, genomics, and biotechnology of chloroplasts and mitochondria.

scholarly journals BonMOLière: Small-Sized Libraries of Readily Purchasable Compounds, Optimized to Produce Genuine Hits in Biological Screens across the Protein Space

2021 ◽  
Vol 22 (15) ◽  
pp. 7773
Author(s):  
Neann Mathai ◽  
Conrad Stork ◽  
Johannes Kirchmair
Keyword(s):  
Large Scale ◽  
Computational Approach ◽  
Large Sets ◽  
Compound Libraries ◽  
Wide Range ◽  
Protein Space ◽  
High Chance ◽  
Large Scale Screening ◽  
Early Drug ◽  
Selection Of

Experimental screening of large sets of compounds against macromolecular targets is a key strategy to identify novel bioactivities. However, large-scale screening requires substantial experimental resources and is time-consuming and challenging. Therefore, small to medium-sized compound libraries with a high chance of producing genuine hits on an arbitrary protein of interest would be of great value to fields related to early drug discovery, in particular biochemical and cell research. Here, we present a computational approach that incorporates drug-likeness, predicted bioactivities, biological space coverage, and target novelty, to generate optimized compound libraries with maximized chances of producing genuine hits for a wide range of proteins. The computational approach evaluates drug-likeness with a set of established rules, predicts bioactivities with a validated, similarity-based approach, and optimizes the composition of small sets of compounds towards maximum target coverage and novelty. We found that, in comparison to the random selection of compounds for a library, our approach generates substantially improved compound sets. Quantified as the “fitness” of compound libraries, the calculated improvements ranged from +60% (for a library of 15,000 compounds) to +184% (for a library of 1000 compounds). The best of the optimized compound libraries prepared in this work are available for download as a dataset bundle (“BonMOLière”).

scholarly journals What Do Meditators Do When They Meditate? Proposing a Novel Basis for Future Meditation Research

Mindfulness ◽  
2021 ◽  
Author(s):  
Karin Matko ◽  
Ulrich Ott ◽  
Peter Sedlmeier
Keyword(s):  
Qualitative Study ◽  
Quantitative Study ◽  
Literature Search ◽  
Comprehensive Overview ◽  
Contemplative Practices ◽  
Comprehensive List ◽  
Scientific Investigations ◽  
Wide Range ◽  
Vast Range ◽  
Selection Of

Abstract Objectives Meditation is an umbrella term for a vast range of contemplative practices. Former proposals have struggled to do justice to this variety. To our knowledge, there is to date no comprehensive overview of meditation techniques spanning all major traditions. The present studies aimed at providing such a comprehensive list of meditation techniques. Methods In a qualitative study, we compiled a collection of 309 meditation techniques through a literature search and interviews with 20 expert meditators. Then, we reduced this collection to 50 basic meditation techniques. In a second, quantitative study, 635 experienced meditators from a wide range of meditative backgrounds indicated how much experience they had with each of these 50 meditation techniques. Results Meditators’ responses indicated that our choice of techniques had been adequate and only two techniques had to be added. Our additional statistical and cluster analyses illustrated preferences for specific techniques across and within diverse traditions as well as sets of techniques commonly practiced together. Body-centered techniques stood out in being of exceptional importance to all meditators. Conclusions In conclusion, we found an amazing variety of meditation techniques, which considerably surpasses previous collections. Our selection of basic meditation techniques might be of value for future scientific investigations and we encourage researchers to use this set.

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