scholarly journals Issues related to an attempt to recreate the geometry of a non-standard spur gear

2021 ◽  
Vol 1199 (1) ◽  
pp. 012105
Author(s):  
K Konecki ◽  
D Wojtkowiak ◽  
K Talaśka ◽  
A Kołodziej ◽  
G Domek
Keyword(s):  
Reverse Engineering ◽  
Test Object ◽  
Spur Gear ◽  
Spare Parts ◽  
Geometric Parameters ◽  
Design And Technology ◽  
Involute Gear ◽  
Modern Machine ◽  
Selection Of ◽  
Made In

Abstract Modern machine manufacturers are making the design and technology of their products more and more complicated. This is to protect against a frequently used practice at customers, i.e. making extra parts on your own. This is because entrepreneurs often cannot afford to order expensive original spare parts and - using reverse engineering - prepare working drawings and commission the components to be made in their own machine park or externally from local suppliers. However, the matter is more complex in the case of gears, which so far have been designed on the basis of the selection of standard geometric parameters. A small modification of one or more of these parameters is enough and it becomes very difficult to recreate the geometry of such a gear. This paper presents the issues related to the reverse engineering of a spur involute gear with very non-standard parameters m = 4.98, α = 26.325 °, x = 0.0695, y = 0.795, c* = 0.383. Further metrological steps were proposed that should be taken to correctly identify at least the fact that the test object is not a part produced by standard modular tools (Fellows cutter, Maag rack cutter, worm cutter, etc.). The work also includes short graphical analyzes of the recreated geometry.

scholarly journals Alternative methods of verifying the reconstructed outline of a non-standard spur gear

2021 ◽  
Vol 1199 (1) ◽  
pp. 012001
Author(s):  
K Konecki ◽  
R Pytliński ◽  
A Kołodziej ◽  
G Domek
Keyword(s):  
Reverse Engineering ◽  
Gear Tooth ◽  
Tolerance Analysis ◽  
Spur Gear ◽  
Geometric Parameters ◽  
Alternative Methods ◽  
Industrial Practice ◽  
Involute Gear

Abstract Common methods of checking a gear that have been designed in reverse engineering are, for example, measurement with a modular caliper or disc micrometer. However, although these methods are among the most accurate, they allow only one or a few of the selected geometric parameters to be measured. The paper presents alternative methods of verification of the reconstructed outline of a very non-standard involute gear with the parameters m = 4.98, α = 26.325 °, x = 0.0695, y = 0.795, c* = 0.383. These methods are less accurate than the classic ones, but they allow for a comprehensive check of the entire outline of the reconstructed tooth. They are often used in industrial practice. However, here, in addition to the methodology, a short tolerance analysis was also carried out, which may to some extent compensate for the aforementioned measurement inaccuracy. The method consists in using the potential of a spreadsheet and CAD technique to generate an involute outline of a gear tooth whose geometry is recreated.

WINTER WHEAT DEVELOPED BY THE UDMURT RESEARCH INSTITUTE OF AGRICULTURE IN COMPETITIVE VARIETY TESTING

2020 ◽  
pp. 5-16
Author(s):  
I.V. TORBINA ◽  
◽  
I.R. FARDEYEVA ◽  
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Biological Characteristics ◽  
Commercial Use ◽  
Breeding Material ◽  
Rotation Pattern ◽  
Selection Of ◽  
Variety Testing ◽  
Made In ◽  
Research Institute

The paper assesses the promising varieties of winter wheat in a competitive variety test by the main economic and biological characteristics that determine the suitability of the variety for commercial use. The object of research was the authors’ own breeding material. The experiments on the selection of winter wheat were made in the experimental crop rotation pattern of the Institute.

Evidence-based Assessment

2010 ◽  
pp. 76-98
Author(s):  
John Hunsley ◽  
Eric J. Mash
Keyword(s):  
Decision Making ◽  
Clinical Assessment ◽  
Assessment Process ◽  
Evidence Based ◽  
The Past ◽  
Specific Assessment ◽  
The Many ◽  
Selection Of ◽  
Made In

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.

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 Clinical Study to Correlate the Facial Form and Maxillary Central Incisor Tooth Form in Males and Females of Davangere Population

2016 ◽  
Vol 04 (03) ◽  
pp. 156-164
Author(s):  
Deepak Bansal ◽  
Shruti Sharma ◽  
Manjit Kumar ◽  
Amrit Khosla
Keyword(s):  
Facial Appearance ◽  
Central Incisor ◽  
Incisor Tooth ◽  
Maxillary Central Incisor ◽  
Anterior Teeth ◽  
The Face ◽  
Tooth Form ◽  
Males And Females ◽  
Selection Of ◽  
Made In

AbstractAn altered facial appearance is more difficult to face, than problems related to ill-fitting denture or eating. The selection of maxillary anterior teeth for complete denture has long posed problem in clinical practice and a controversy about the best method to employ still exists. An attempt is made in the present study to clinically correlate the face form with maxillary central incisor tooth form in males and females of Davangere population. In 1914, Leon William's projected the “the form method” where he classified facial forms as square, tapering, and ovoid. Maxillary central incisors were selected according to the facial forms.Of total 100 subjects four different tooth forms and face forms were evaluated. They are: square, ovoid, square-tapered, tapered. No significant correlation existed between face form in male and females. Females exhibited greater correlation between face forms and inverted tooth form but that correlation is not sufficient to serve as a guide for selection of anterior teeth.

New Development in High Efficiency Deep Grinding

2012 ◽  
Author(s):  
Andre D. L. Batako ◽  
Valery V. Kuzin ◽  
Brian Rowe
Keyword(s):  
Machine Tool ◽  
High Efficiency ◽  
Machining Process ◽  
Depth Of Cut ◽  
Removal Rates ◽  
Workpiece Surface ◽  
New Development ◽  
Cutting Processes ◽  
Selection Of ◽  
Made In

High Efficiency Deep Grinding (HEDG) has been known to secure high removal rates in grinding processes at high wheel speed, relatively large depth of cut and moderately high work speed. High removal rates in HEDG are associated with very efficient grinding and secure very low specific energy comparable to conventional cutting processes. Though there exist HEDG-enabled machine tools, the wide spread of HEDG has been very limited due to the requirement for the machine tool and process design to ensure workpiece surface integrity. HEDG is an aggressive machining process that requires an adequate selection of grinding parameters in order to be successful within a given machine tool and workpiece configuration. This paper presents progress made in the development of a specialised HEDG machine. Results of HEDG processes obtained from the designed machine tool are presented to illustrate achievable high specific removal rates. Specific grinding energies are shown alongside with measured contact arc temperatures. An enhanced single-pole thermocouple technique was used to measure the actual contact temperatures in deep cutting. The performance of conventional wheels is depicted together with the performance of a CBN wheel obtained from actual industrial tests.

scholarly journals Recent advances in the electrochemical construction of heterocycles

2014 ◽  
Vol 10 ◽  
pp. 2858-2873 ◽  
Author(s):  
Robert Francke
Keyword(s):  
Heterocyclic Compounds ◽  
Elevated Temperatures ◽  
Ring Formation ◽  
Environmentally Benign ◽  
Heterocyclic Chemistry ◽  
Ambient Conditions ◽  
Recent Developments ◽  
Strong Acids ◽  
Selection Of ◽  
Made In

Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.

Maintenance and Parts Fabrication by Reverse Engineering

1999 ◽  
Author(s):  
Sayed M. Metwalli ◽  
M. Alaa E. Radwan ◽  
Osama Abdel-Wehab ◽  
Owaise Shalaby ◽  
Youssria A. Moussa ◽  
...  
Keyword(s):  
Reverse Engineering ◽  
Spare Parts ◽  
Geometrical Configuration ◽  
Proof Of Concept ◽  
Industrial Plants ◽  
Industrial Base ◽  
Skilled Manpower ◽  
Casting Industry ◽  
Major Industry ◽  
Re Methods

Abstract With the collapse of the Eastern block, once Egypt’s major industry supplier for machinery and spare parts, and the lack of skilled manpower, the Egyptian industry is finding it difficult to maintain its machinery and industrial base and to compete with the much more sophisticated and coordinated industries abroad. The cutoff of supply of maintenance parts from the Eastern Block, prompt the use of modern reverse engineering (RE) methods in the capturing the geometrical configuration and fabrication of rare maintenance parts, in support of the Egyptian Industry. This paper demonstrates, as a proof of concept, the use of the technology of RE in the fabrication of parts. The success of the experiment initiated a much wider application to the technology, that of patterns making in support of the casting industry. This will provide an accurate and expeditious means to properly maintain industrial plants and produce compatible spare pails urgently needed.

An analytical model of an I-cored coil located above a conductive material with a hole

2018 ◽  
Vol 82 (2) ◽  
pp. 21001
Author(s):  
Grzegorz Tytko ◽  
Leszek Dziczkowski
Keyword(s):  
Test Object ◽  
Middle Layer ◽  
Axially Symmetric ◽  
The Finite Element Method ◽  
Cylindrical Coordinate ◽  
Air Space ◽  
Through Hole ◽  
Tree Method ◽  
Good Agreement ◽  
Made In

The paper examines the problem of an axially symmetric I-cored coil located above a three-layered plate with a hole in the middle layer. A cylindrical coordinate system was applied, wherein the solution domain was truncated in the radial direction. The employment of the truncated region eigenfunction expansion (TREE) method resulted in deriving the final formulas for the change of the coil impedance with regard to the air space, and also pertaining to the test object without a flaw. Formulas for various configurations of the test object, among others for a surface hole, a subsurface hole and a through hole, have been presented. For the purpose of defectoscopy, the influence of the hole in the plate on the impedance components was investigated. The calculations were made in Matlab for frequencies from 100 Hz to 50 kHz. The obtained results were verified using the finite element method (FEM) in Comsol Multiphysics package. A very good agreement was observed in the case of both the resistance and reactance.

Book Reviews

2000 ◽  
Vol 38 (1) ◽  
pp. 115-165 ◽  
Keyword(s):  
English Language ◽  
Value Added ◽  
General Purpose ◽  
Original Research ◽  
Book Selection ◽  
Economic Association ◽  
Single Well ◽  
Selection Of ◽  
Made In

Editor's Note: Guidelines for Selecting Books to Review Occasionally, we receive questions regarding the selection of books reviewed in the Journal of Economic Literature. A statement of our guidelines for book selection might be useful, therefore. The general purpose of our book reviews is to help keep members of the American Economic Association informed of significant English-language publications in economics research. Annotations are published of all books received. However, we receive many more books than we are able to review so choices must be made in selecting books for review. We try to identify for review scholarly, well-researched books that embody serious and original research on a particular topic. We do not review textbooks. Other things equal, we avoid volumes of collected papers such as festschriften and conference volumes. Often such volumes pose difficult problems for the reviewer who may find himself having to describe and evaluate many different contributions. Among such volumes, we prefer those on a single, well-defined theme that a typical reviewer may develop in his review. A volume that collects together papers from a wide assortment of different topics is not preferred to one devoted exclusively to one topic. We avoid volumes that collect previously published papers unless there is some material value added from bringing the papers together. Also, we refrain from reviewing second or revised editions unless the revisions of the original edition are really substantial. Our policy is not to accept offers to review (and unsolicited reviews of) particular books. We have examined the consequences of an alternative policy and have determined that we lack the resources to deal appropriately with unsolicited reviews. Coauthorship of reviews is not forbidden but discouraged and we ask our invited reviewers to discuss with us first any changes in the authorship or assigned length of a review. [Reprinted from JEL, March 1992, 30(1), p. vi.]

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