THE ACCURACY OF AN ACCELERATED METHOD FOR THE EVALUATION OF LIFE OF CYLINDRICAL GEARS WITH PROFILE CORRECTION

This paper presents an accelerated method for the evaluation of life of cylindrical gears with profile correction. Compared to a more accurate solution based on the generalized method for evaluating the wear and life of cylindrical involute gears, the new method enables accelerating this process by over 16000 times. The method was used to estimate the life of a cylindrical spur gear depending on different ranges of blocks describing gear teeth meshing conditions (i.e. the number of gear revolu-tions). The accuracy of the results obtained thereby was examined, too. It has been found that when the range of a block is increased by 3000 times, the deviations of the numerical solution are below 0.5%

Reliability and Validity of Measurement Tools for Residual Limb Volume in People With Limb Amputations: A Systematic Review

Background Measurements of residual limb volume often guide decisions on the type and timing of prosthetic prescription. To help inform these decisions, it is important that clinicians use measurement tools that are reliable and valid. Purpose The aim of this systematic review was to investigate the reliability and validity of measurement tools for residual limb volume in people with limb amputations. Data Sources A comprehensive search on MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science was performed on July 11, 2016. Study Selection Studies were included if they examined the reliability or validity of measurement tools for residual limb volume, were conducted on humans, and were published in English. Data Extraction Data were extracted from 11 reliability and 4 validity studies and included study characteristics, volumetric estimates, and reliability and validity estimates. The quality of the studies was also rated. Data Synthesis Data from 2 studies (38 participants) indicated good to excellent intrarater (intraclass correlation coefficient [ICC] ≥0.88) and interrater (ICC ≥0.88) reliability and high between-session reliability (coefficient of variation [CV] = 10%) for water displacement volumetry. One study (28 participants) reported excellent intrarater and interrater reliability (ICC ≥0.93) for the circumferential method, and data from 2 studies (19 participants) indicated high between-session reliability for the optical surface scanner (CV ≤9.8%). Three studies (26 participants) indicated good to excellent between-session reliability results for computed tomography (CV = 9.2%–10.9%). One study (7 participants) showed moderate within-session reliability (CV = 50%). Using water displacement volumetry as the gold standard, 2 studies (79 participants) indicated excellent validity for the circumferential method ( r ≥0.92; ICC ≥0.92). All studies reporting measures of reliability or validity were performed with people who had transtibial amputations. Limitations Only studies published in English and in which water displacement volumetry was used as the gold standard were included in this review. The reliability and validity of the quality rating scale used in this review have not been tested. Conclusions On the basis of a limited number of moderate- to high-quality studies with small sample sizes, circumferential and water displacement methods were found to be reliable, and the circumferential method was found to be valid in people with transtibial amputations. There are inadequate data for drawing conclusions about volume measurement methods in people with other types of limb amputations

Oncology Section EDGE Task Force on Urogenital Cancer Outcomes: Clinical Measures of Lymphedema—A Systematic Review

Background: Valid and reliable tools to assess lymphedema are necessary to accurately evaluate status and to objectively document and measure the results of interventions. Understanding the advantages and disadvantages of each measure can inform the clinician\u27s choice of the appropriate tool to be used in the clinic or research setting. Purpose: To identify reliable and valid measurement techniques that are sensitive to change for assessing edema volume or soft tissue change in the lower extremities or genital region of patients with lymphedema. Methods: A systematic review of the literature was conducted to assess the published psychometric properties and clinical feasibility of each method identified. Task Force members independently reviewed each measure using the Cancer EDGE Rating Form. Results: Both water displacement and circumferential measurement methods by tape measure were rated as Highly Recommended to quantify lower-extremity limb volume. Water displacement was determined to be the criterion standard by which all other assessments of volume are benchmarked. Both optoelectric volumetry and bioelectric impedance analysis were rated as Recommended, and ultrasound was rated Not Recommended. Conclusion: The Urogenital Cancer EDGE Task Force highly recommends water displacement and circumferential tape measurement for use as reliable methods for assessment and documentation of change of limb volume in this patient population. Early detection of subclinical lower-extremity lymphedema in this patient population remains challenging, as there is no “index” limb that can be proven to be uninvolved in a patient population with documented pelvic node dissection/irradiation. No articles were found to support valid and reliable genital lymphedema volume measurement

Influence estimation of sliding bearing details ovality on the longevity according to generalized cumulative wear model

Przedstawiono wyniki rozwiązania zagadnienia stykowego z zużyciem dla łożyska ślizgowego w przypadku owalności tulei i wału z wykorzystaniem metody ekspresowej procesu obliczeń. Zostały przebadane jednoobszarowy oraz mieszany schematy współdziałania w łożysku. Ustalono prawidłowości wpływu wielkości bloku stałych warunków kontaktu oraz zakresu dyskretyzacji zarysu wału z owalnością na trwałość łożyska. Oprócz tego został przebadany wpływ luzu promieniowego na trwałość łożyska.The solution results of contact problem and wear for sliding bearing under the existence of bush and shaft ovality are given using the express-method of calculations. Single-area and mixed schemes of interaction in the bearing are researched. The legitimacies of the influence of block size with constant contact conditions and discretization interval of shaft contour with ovality on the bearing longevity are determined. Besides, the influence of radial clearance on the bearing longevity is also researched

Research of tribocontact interaction mechanics in cylindrical conjunctions with inside hertz contact

Na podstawie metody autorskiej badania mechaniki styku w połączeniu cylindrycznym oraz kinetyki jego zużywania przy tarciu ślizgowym przeprowadzono analizę numeryczną obszaru zastosowania klasycznego wzoru Hertza dla określenia nacisków stykowych. Zmodyfikowano wzory Hertza celem oszacowania maksymalnych nacisków stykowych oraz kąta styku przy zużyciu wskazanych układów tribologicznych. Wyniki numerycznej oceny według obu metod wstępnych nacisków stykowych oraz ich zmiany w wyniku zużycia podano w postaci graficznej. Został przebadany wpływ obciążenia oraz luzu promieniowego w połączeniu na jego trwałość.On the basis of the author's research method of cylindrical conjunction contact mechanics and wear kinetics during sliding friction, numeral analysis of classical Hertz formula using sphere for contact pressures has been made. Hertz formulas for the valuation of tribocontact pressures and angles during appointed tribosystems wear have been modified. The results of numerical valuation, according to both methods of contact and tribocontact pressures, are presented graphically. Additionally, the influence of loading and rational clearance on its longevity has been investigated

The wear influence assessment method on contact strength and durability of worm gear with Archimedean worm

Przedstawiono zmodyfikowaną metodę na oszacowanie wpływu zużycia zębów przekładni ślimakowej ze ślimakiem Archimedesa na wytrzymałość stykową oraz trwałość. Ustalono prawidłowość wpływu zużywania na badane parametry.The modified wear influence assessment method of worm gears with Archimedean worm on contact strength and durability has been filed. The regularities of wear influence on the investigated parameters have been established

Computer Simulation of the Impact of Optimization of Width in the Helical Cylindrical Gear on Bearing and Durability. Part 1. Height Correction of the Gear Profile

Based on the elaborated calculation method he authors method for determining the wear and durability of gears was employed to measure the maximum contact pressures, linear wear of teeth and durability of the gear with height correction of the profile. The optimal condition width in involute helical gears is indicated ensuring constant length of the line of contact between the meshing gears. As a result, it was possible to determine variations in the parameters for the optimized gear describing the meshing gears at different values of the profile correction coefficients

Ewolucja podatku od spadków i darowizn z punktu widzenia celów ekonomicznych

Evolution of donation and inheritance taxes in the aspect of economic targetsThe article describes economic role of donation and inheritance taxes. In the first part of the article the author presents evolution of these taxes, from ancient times to present, and also considers functioning of these taxes in Poland from times of the First Republic of Poland. The role of these taxes in Poland from the 90’s to present is thoroughly analysed. In conclusion the author states that donation and inheritance taxes do not play the fundamental role in realization of economic aims and do not have a significant influence on economic development.Evolution of donation and inheritance taxes in the aspect of economic targetsThe article describes economic role of donation and inheritance taxes. In the first part of the article the author presents evolution of these taxes, from ancient times to present, and also considers functioning of these taxes in Poland from times of the First Republic of Poland. The role of these taxes in Poland from the 90’s to present is thoroughly analysed. In conclusion the author states that donation and inheritance taxes do not play the fundamental role in realization of economic aims and do not have a significant influence on economic development

Accelerated methods for estimating the durability of plain bearings

The paper presents methods for determining the durability of slide bearings. The developed methods enhance the calculation process by even 100000 times, compared to the accurate solution obtained with the generalized cumulative model of wear. The paper determines the accuracy of results for estimating the durability of bearings depending on the size of blocks of constant conditions of contact interaction between the shaft with small out-of-roundedness and the bush with a circular contour. The paper gives an approximate dependence for determining accurate durability using either a more accurate or an additional method