scholarly journals Free oscillations of steel beams prestressed by wall stretching

2020 ◽  
Vol 17 (6) ◽  
pp. 97-103
Author(s):  
V. A. Kravchuk ◽  
Keyword(s):  
Free Oscillation ◽  
Forced Oscillations ◽  
Steel Beams ◽  
Load Bearing Capacity ◽  
Study Results ◽  
Oscillation Process ◽  
Circular Frequency ◽  
The Impact ◽  
Resistance Forces ◽  
Prestressed Beams

The article presents the study results of the impact of steel beam prestressing by wall stretching on changes in the circular frequency, frequency, period, and number of oscillations per minute for free oscillation, and for oscillation taking into account the resistance forces. The forced oscillations of the beam under impulse loading are investigated. There has been carried out a comparative analysis of the dynamic parameters of prestressed beams and conventional beams of equal cross-section with the same load-bearing capacity parameters. The analysis results of the influence of resistance forces on the oscillation process in prestressed beams and conventional beams are submitted. There has been established the time of oscillations damping in the compared beams at free oscillation, taking into account the resistance forces.

TEXTILE SYNTHETIC SHEETS AND THEIR IMPACT ON THE LOAD BEARING CAPACITY OF CONCRETE-FILLED TEXTILE FLOOR-MATS

2017 ◽  
Vol 7 (3) ◽  
pp. 57-62
Author(s):  
Andrey A. MIKHASEK ◽  
Maxim V. RODIONOV ◽  
Margarita G. LITVINOVA
Keyword(s):  
Bearing Capacity ◽  
Laboratory Study ◽  
Concrete Slabs ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Study Results ◽  
Mat Thickness ◽  
The Impact

The calculation of the strength of concrete slabs load bearing capacity does not take into account synthetic sheets impact while calculating concrete-fi lled textile fl oor-mats. Further studies are proposed to assess the impact of sheets in laboratory environments. The authors base their study on the properties of concrete-fi lled textile fl oor-mats as fl exible beams and on synthetic sheets impact on strength indicators. The paper presents a laboratory study results obtained under diff erent conditions of textile synthetic sheets impact on concrete-fi lled textile fl oor-mats load bearing capacity. It provides a function to determine a mat thickness from the condition of its strength.

scholarly journals INVESTIGATION INTO THE IMPACT OF SUSPENSION PARAMETERS OF FREIGHT WAGONS ON RUNNING SMOOTHNESS / PREKINIŲ VAGONŲ PAKABOS PARAMETRŲ ĮTAKOS VAŽIAVIMO TOLYGUMUI TYRIMAS

2014 ◽  
Vol 6 (5) ◽  
pp. 538-545
Author(s):  
Vytautas Balevičius ◽  
Stasys Steišiūnas ◽  
Gintautas Bureika
Keyword(s):  
Software Package ◽  
The Body ◽  
Forced Oscillations ◽  
Rolling Stock ◽  
Suspension Parameters ◽  
Oscillation Process ◽  
The Impact ◽  
The Given ◽  
Universal Mechanism ◽  
Track Irregularities

The paper analyses the running smoothness of the rolling-stock as the main feature of wagon dynamics. The running smoothness of the freight wagon is evaluated considering the parameters of vibrations and the oscillation process. During the process of wagon running on the track, the forced oscillations of the elements of the body, chassis and suspension are excited. Four-axle freight wagon movement down the track taking into account the given vertical and lateral irregularities has been simulated using software package “Universal Mechanism”. The dependencies of the oscillation amplitudes of the wagon body on track irregularities and vertical and lateral suspension settings have been defined. The dependencies of wagon suspension settings and derailment stability on changes in the wagon mass have been examined in the paper. Finally, basic conclusions have been given. Straipsnyje nagrinėjama viena pagrindinių vagono dinamikos savybių – važiavimo tolygumas. Riedmenų važiavimo tolygumas vertinamas jų masių svyravimo proceso ir kėbulo vibracijų parametrais. Vagonui važiuojant bėgių kelio nelygumais, sužadinami priverstiniai kėbulo, pakabos ir važiuoklės elementų svyravimai. Programiniu paketu „Universal Mechanism“ sumodeliuotas prekinio keturašio vagono važiavimas keliu, kuriame yra bėgių vertikalių ir skersinių nelygumų. Nustatyta vagono kėbulo svyravimų amplitudžių priklausomybė nuo bėgių kelio nelygumų bei vertikaliųjų ir skersinių pakabos parametrų. Straipsnyje nagrinėjama vagono pakabos parametrų ir stabilumo nuriedėjimui nuo bėgių atveju priklausomybė, kintant vagono masei. Pabaigoje pateiktos išvados.

scholarly journals Influence of shear on plastic bending strength of I cross-sections steel beams

2021 ◽  
Vol 1203 (2) ◽  
pp. 022009
Author(s):  
Pavol Juhás ◽  
Ingrid Juhásová Šenitková
Keyword(s):  
Flexural Strength ◽  
Cross Sections ◽  
Bending Strength ◽  
Steel Structures ◽  
Steel Beams ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Load Bearing Capacity ◽  
Shear Effects ◽  
The Impact

Abstract In general, steel beams are stressed by bending and shear. Due to the loading a normal stresses σ and shear stresses τ arise in individual cross-sections of steel beams. But they are usually stressed mainly by bending. This follows both from several theoretical analyzes and especially from the corresponding experiments. Therefore, current standards for the design of steel structures allow the impact of shear to be neglected to a certain level of shear stress of the most stressed - decisive cross-sections of beams (EN 1993-1-1, respectively CSN EN 1993-1-1 and others). However, in the case of shorter beams, especially in places of support and in places of application of concentrated forces, the shear effects of the load can also be significant. In the case of more significant shear effects of the load, the plastic flexural strength of the decisive cross-sections and also the overall load-bearing capacity of the steel beams must be adequately reduced. However, the degree of flexural strength reduction with a significant effect of shear in the case of I cross-sections is still unambiguous. It is therefore important to experimentally investigate steel beams in the area of significant shear effects. The presented article contains selected results of experimental investigation of the significant effect of shear on the flexural strength of steel beams I cross-sections.

Income Diversification and Bank Efficiency in Vietnam

2017 ◽  
pp. 52-67
Author(s):  
Sang Nguyen Minh
Keyword(s):  
Regression Model ◽  
Commercial Banks ◽  
Banking System ◽  
Operational Efficiency ◽  
Commercial Banking ◽  
Tobit Regression ◽  
Income Diversification ◽  
Positive Effects ◽  
Study Results ◽  
The Impact

This study uses the DEA (Data Envelopment Analysis) method to estimate the technical efficiency index of 34 Vietnamese commercial banks in the period 2007-2015, and then it analyzes the impact of income diversification on the operational efficiency of Vietnamese commercial banks through a censored regression model - the Tobit regression model. Research results indicate that income diversification has positive effects on the operational efficiency of Vietnamese commercial banks in the research period. Based on study results, in this research some recommendations forpolicy are given to enhance the operational efficiency of Vietnam’s commercial banking system.

Some reflections on social structure: Theoretical and practical aspects

2020 ◽  
Vol 18 (6) ◽  
pp. 1063-1078
Author(s):  
T.N. Skorobogatova ◽  
I.Yu. Marakhovskaya
Keyword(s):  
Service Industry ◽  
External Factors ◽  
Infrastructure Development ◽  
Social Infrastructure ◽  
Social Sphere ◽  
The Social ◽  
Study Results ◽  
The Republic ◽  
Internal And External Factors ◽  
The Impact

Subject. This article discusses the role of social infrastructure in the national economy and analyzes the relationship between the notions of Infrastructure, Service Industry and Non-Productive Sphere. Objectives. The article aims to outline a methodology for development of the social infrastructure of Russia's regions. Methods. For the study, we used the methods of statistical and comparative analyses. The Republic of Crimea and Rostov Oblast's social infrastructure development was considered as a case study. Results. The article finds that the level of social infrastructure is determined by a number of internal and external factors. By analyzing and assessing such factors, it is possible to develop promising areas for the social sphere advancement. Conclusions. Assessment and analysis of internal factors largely determined by the region's characteristics, as well as a comprehensive consideration of the impact of external factors will help ensure the competitiveness of the region's economy.

The Impact of Bar Service Operation Practices on Organizational Performance in Indian Hotel Industry

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohinder C. Dhiman ◽  
Abhishek Ghai
Keyword(s):  
Organizational Performance ◽  
Hotel Industry ◽  
Demographic Variables ◽  
Study Results ◽  
Service Operation ◽  
Managerial Implications ◽  
Overall Performance ◽  
The Impact ◽  
The Relationship ◽  
Bivariate Test

The paper has a two fold purpose - examine the impact of bar service operation practices (BSOP) on organizational performance (OP) and study the relationship between organizational performance and demographic variables. Based on a survey of 362 bar managers perceptions on the impact of bar service operation practices on organizational performance were assessed by 59 practices and 6 demographic variables. Bivariate test and ANOVA were employed to test the working hypothesis in the study. Results indicated that there is a positive relationship between the bar service operation practices and organizational performance. Further, the results indicate some practical and managerial implications to improve organizational overall performance.

scholarly journals Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich
Keyword(s):  
Life Cycle ◽  
Lithium Ion Batteries ◽  
Electric Vehicles ◽  
Energy Demand ◽  
Lithium Ion ◽  
Life Cycles ◽  
Future Research ◽  
Research Areas ◽  
Study Results ◽  
The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

scholarly journals Robust Step Detection from Different Waist-Worn Sensor Positions: Implications for Clinical Studies

2020 ◽  
Vol 4 (1) ◽  
pp. 50-58
Author(s):  
Matthias  Tietsch ◽  
Amir Muaremi ◽  
Ieuan Clay ◽  
Felix Kluge ◽  
Holger Hoefling ◽  
...  
Keyword(s):  
Clinical Study ◽  
Clinical Studies ◽  
Neurological Diseases ◽  
Human Gait ◽  
Robust Solution ◽  
Step Detection ◽  
Study Protocols ◽  
Study Results ◽  
Wide Range ◽  
The Impact

Analyzing human gait with inertial sensors provides valuable insights into a wide range of health impairments, including many musculoskeletal and neurological diseases. A representative and reliable assessment of gait requires continuous monitoring over long periods and ideally takes place in the subjects’ habitual environment (real-world). An inconsistent sensor wearing position can affect gait characterization and influence clinical study results, thus clinical study protocols are typically highly proscriptive, instructing all participants to wear the sensor in a uniform manner. This restrictive approach improves data quality but reduces overall adherence. In this work, we analyze the impact of altering the sensor wearing position around the waist on sensor signal and step detection. We demonstrate that an asymmetrically worn sensor leads to additional odd-harmonic frequency components in the frequency spectrum. We propose a robust solution for step detection based on autocorrelation to overcome sensor position variation (sensitivity = 0.99, precision = 0.99). The proposed solution reduces the impact of inconsistent sensor positioning on gait characterization in clinical studies, thus providing more flexibility to protocol implementation and more freedom to participants to wear the sensor in the position most comfortable to them. This work is a first step towards truly position-agnostic gait assessment in clinical settings.

scholarly journals IMPACT OF LAPAROSCOPIC COLORECTAL SURGERY ON BODY IMAGE

2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
A Fernández Candela ◽  
L Sánchez-Guillén ◽  
L García Catalá ◽  
C Curtis Martínez ◽  
M Bosch Ramírez ◽  
...  
Keyword(s):  
Body Image ◽  
Colorectal Surgery ◽  
Laparoscopic Colorectal Surgery ◽  
Wound Complication ◽  
Descriptive Study ◽  
Surgical Quality ◽  
Body Image Scale ◽  
Study Results ◽  
The Impact ◽  
Observational Descriptive Study

Abstract INTRODUCTION The aim of this study is to evaluate the impact of laparoscopic colorectal surgery (LCS) on body image using the validated Body Image Scale (BIS) as a parameter of surgical quality. MATERIAL AND METHODS We conducted an observational descriptive study. Patients who underwent scheduled LCS between June 2015 and December 2019 by a General Hospital Coloproctology Unit were included. RESULTS The sample included 180 patients, 115 men (63.9%) and 65 women (36.1%) with a median age of 67 years. Right hemicolectomies (31.7%) and sigmoidectomies (28.3%) were the main procedures performed. In most patients, a suprapubic (69.4%) or transverse (19.4%) incision was made. 21.9% suffered some type of postoperative complication (13.9% wound complication, 10.6% incisional hernia). The general result of the BIS questionnaire was satisfactory, with a median of 0 in the responses (no alteration of body image). We found that 46.2% of the women had some alteration in body image, compared to 28.7% of the men (p = 0.018) and low and ultra-low anterior resection were the surgeries that obtained worst scores, with 13,5% and 12,5% respectively of patients with a BIS score above 5 (p = 0.044). Patients with a stoma also obtained worst punctuation (25% above 5 vs 6,1%, p = 0.001). No statistically significant differences were found regarding type of incision, presence of complications and anxiety or depression. CONCLUSION Study results show, in general, good post-surgical body image after LCS. However, patients with stoma and women were more dissatisfied. Interestingly, there is no worse body image due to type of incision, so we recommend the least iatrogenic one.

scholarly journals Variation in performance on common content items at UK medical schools

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
David Hope ◽  
David Kluth ◽  
Matthew Homer ◽  
Avril Dewar ◽  
Richard Fuller ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Standard Setting ◽  
Medical Schools ◽  
Cross Sectional Study ◽  
Pass Rates ◽  
Cross Sectional ◽  
Study Results ◽  
Institutional Differences ◽  
Common Content ◽  
The Impact

Abstract Background Due to differing assessment systems across UK medical schools, making meaningful cross-school comparisons on undergraduate students’ performance in knowledge tests is difficult. Ahead of the introduction of a national licensing assessment in the UK, we evaluate schools’ performances on a shared pool of “common content” knowledge test items to compare candidates at different schools and evaluate whether they would pass under different standard setting regimes. Such information can then help develop a cross-school consensus on standard setting shared content. Methods We undertook a cross-sectional study in the academic sessions 2016-17 and 2017-18. Sixty “best of five” multiple choice ‘common content’ items were delivered each year, with five used in both years. In 2016-17 30 (of 31 eligible) medical schools undertook a mean of 52.6 items with 7,177 participants. In 2017-18 the same 30 medical schools undertook a mean of 52.8 items with 7,165 participants, creating a full sample of 14,342 medical students sitting common content prior to graduation. Using mean scores, we compared performance across items and carried out a “like-for-like” comparison of schools who used the same set of items then modelled the impact of different passing standards on these schools. Results Schools varied substantially on candidate total score. Schools differed in their performance with large (Cohen’s d around 1) effects. A passing standard that would see 5 % of candidates at high scoring schools fail left low-scoring schools with fail rates of up to 40 %, whereas a passing standard that would see 5 % of candidates at low scoring schools fail would see virtually no candidates from high scoring schools fail. Conclusions Candidates at different schools exhibited significant differences in scores in two separate sittings. Performance varied by enough that standards that produce realistic fail rates in one medical school may produce substantially different pass rates in other medical schools – despite identical content and the candidates being governed by the same regulator. Regardless of which hypothetical standards are “correct” as judged by experts, large institutional differences in pass rates must be explored and understood by medical educators before shared standards are applied. The study results can assist cross-school groups in developing a consensus on standard setting future licensing assessment.

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