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1 – 10 of over 4000Wujiu Pan, Xianmu Li, Lele Sun, Hongxing Song and Minghai Wang
The purpose is to predict the distribution of the residual pretightening force of the bolt group under the action of any initial pretightening force, and to achieve the final…
Abstract
Purpose
The purpose is to predict the distribution of the residual pretightening force of the bolt group under the action of any initial pretightening force, and to achieve the final residual pretightening force as the target to solve the initial pretightening force value to be applied.
Design/methodology/approach
Based on the finite element method and the elastic interaction theory between bolt group, this paper establishes a prediction model for the residual pretightening force distribution of bolt group for one-step pretightening and multi-step pretightening of gasketless flange connection systems. In addition, using the general modeling method given in this paper, the prediction model of residual pretightening force of long plate bolt connection system is established, and compared with reference, which fully proves the effectiveness and universality of the general prediction model of residual pretightening force of bolt group.
Findings
The appropriate pretightening sequence, increasing the number of pretightening steps and variable amplitude loading can effectively reduce the influence of elastic interaction and improve the uniformity of residual pretightening force of the bolt group. And the selection of material, number of bolts and connected thickness of bolt connection system also has a great influence on the distribution of residual pretightening force of bolt groups.
Originality/value
The general prediction model for the residual pretightening force of bolt group of connecting structural components considering elastic interaction given in this paper can provide a reference for the design and optimization of the bolt assembly process of the rotor system and the casing system in aero-engine and the prediction of the performance of the connecting system.
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The study is carried out to analytically reconnoiter geotechnical index properties of subgrade soils as key variables that shape the cost profile of road infrastructure projects…
Abstract
Purpose
The study is carried out to analytically reconnoiter geotechnical index properties of subgrade soils as key variables that shape the cost profile of road infrastructure projects in a tropical geographic setting with starkly heterogenous ground conditions.
Design/methodology/approach
Using the Niger Delta region, as a point of reference, data on geotechnical index properties of subgrade soils at spatially dispersed locations for 61 completed highway projects are collated. Exploratory statistical tests were carried out to infer significant associations with final project costs before regression analysis. Regression analysis is principally deployed as an explanatory analytical tool, relevant to quantify the sensitivity of highway project costs to the individual and collective impact of geotechnical variables.
Findings
Several parameters of expansivity and compressibility exhibited significantly strong associations with the final costs recorded on the highway projects. The statistical analysis further established a cause-effect relationship, whereby small changes in the geotechnical properties of sub-grade soils at project locations, would result in disproportionately large changes in the cost of road construction.
Practical implications
The study findings provide insight into the sensitivity of road construction costs to geotechnical variables, which can serve as a useful input in financial risk analysis for development appraisal and the generation of location adjustment factors.
Originality/value
The study statistically demonstrates location-induced construction cost profiles, triggered in response to the spatial geotechnical variability and occurrence of problem subgrade soils in the humid tropics, which may be different from those traditionally established in studies of cold and temperate climate soils.
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Ruben B.O. Acevedo, Klaudia Kantarowska, Edson Costa Santos and Marcio C. Fredel
This paper aims to generate a review of available techniques to measure Residual Stress (RS) in Ti6Al4V components made by Ti6Al4V.
Abstract
Purpose
This paper aims to generate a review of available techniques to measure Residual Stress (RS) in Ti6Al4V components made by Ti6Al4V.
Design/methodology/approach
State of the art; literature review in the field of Residual Stress measurement of Ti6Al4V parts made by selective laser melting (SLM).
Findings
Different Residual Stress measurement techniques were detailed, regarding its concept, advantages and limitations. Regarding all researched references, hole drilling (semi destructive) and X-ray diffraction (nondestructive) were the most cited techniques for Residual Stress measurement of Ti6Al4V parts made by SLM.
Originality/value
An extensive analysis of RS measurement techniques for Ti6Al4V parts made by SLM.
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Seyfe Nigussie Adamu, Temesgen Wondimu Aure and Tesfaye Alemu Mohammed
From the factors that affect shear strength of reinforced concrete (RC) beams, the study examines the effect of controversial parameters, width-to-depth (b/d) and effective…
Abstract
Purpose
From the factors that affect shear strength of reinforced concrete (RC) beams, the study examines the effect of controversial parameters, width-to-depth (b/d) and effective length-to-depth (leff/d) ratio on shear strength of RC slender beams.
Design/methodology/approach
The researchers utilized a database of 676 experimental test results from ACI-DAfStb database, Conducted regression analysis to examine relationship between b/d and leff/d ratios and shear strength, compare and analyze sensitivity to changes in b/d and leff/d ratios for the selected 12 shear models for RC beams.
Findings
Increasing b/d ratio enhanced shear strength until b/d ˜ 3, but further increases had limited impact and increasing leff/d ratio resulted in decreased shear strength. From comparative analysis, the models provided by various design standards were found to be safe, with EC-2 and JSCE models being conservative. From considered research models, Campione and Arslan models were conservative, while Kim and White model were observed to be unsafe. Sensitivity analysis indicated ACI318-19, JSCE, CEB-FIP-90 and Arslan models were sensitive to changes in b/d and leff/d ratios. National code models generally captured shear strength characteristics well. Certain models suggested a constant/decreasing b/d effect despite observed shear strength enhancement. Most models indicated improved shear strength with an increasing leff/d ratio, contrary to experimental findings while TS500 and Hwang models aligned with experimental results.
Research limitations/implications
The study's limitations include the dependence on the available database, which may not encompass all possible experimental scenarios. Further research should aim to expand the database and investigate additional parameters that may influence shear strength in RC beams.
Practical implications
The findings of this study have practical implications for the design and analysis of RC beams by suggesting that the width-to-depth and length-to-depth ratios should be carefully considered to optimize shear strength. The identified models can assist engineers in selecting appropriate shear strength prediction models based on specific design scenarios.
Social implications
The study contributes to the advancement of knowledge in the field of reinforced concrete beam design, which has implications for the safety and reliability of structural systems. By understanding the factors influencing shear strength, engineers can design more efficient and robust structures, ensuring the safety of buildings and infrastructure.
Originality/value
This study provides valuable insights into the influence of the width-to-depth and effective length-to-depth ratios on shear strength in reinforced concrete beams. It contributes to the understanding of these factors and their impact on shear strength, addressing the lack of consensus among researchers. The comparative analysis of shear models and the sensitivity analyses add value by identifying the models that align better with experimental observations. The study emphasizes the need for accurate models that account for these factors and highlights the importance of further research to refine and develop improved predictive models.
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The aim of this study is to examine the trend over time of the demand for .it domain names.This study first assesses whether there is a phase of growth and expansion or at a point…
Abstract
Purpose
The aim of this study is to examine the trend over time of the demand for .it domain names.This study first assesses whether there is a phase of growth and expansion or at a point of saturation. Second, this research can be useful also to compare researches that have considered other internet metrics and other models.
Design/methodology/approach
This paper describes the forecasting methods used to analyze the internet diffusion in Italy. The domain names under the country code top-level domain “.it” have used as metrics. To predict domain names .it the seasonal auto regressive integrated moving average (SARIMA) model and the Holt-Winters (H-W) methods have been used.
Findings
The results show that, to predict domain names .it the SARIMA model is better than the H-W methods. According to the findings, notwithstanding the forecast of a growth in domain names, the increase is however limited (about 3%), tending to reach a phase of saturation of the market of domain names .it.
Originality/value
In general many authors have studied internet diffusion applying statistical models that follow an S-shaped behavior. On the other hand, the more used diffusion models that follow an S-shape not always provide an adequate description of the Internet growth pattern. To achieve this goal, this paper demonstrates how the time series models, in particular SARIMA model and H-W models, fit well in explaining the spread of the internet.
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Pablo Contreras-Contreras, Pedro Cuesta-Valiño and Pablo Gutiérrez-Rodríguez
This study aims to analyze the relationship between expectations of change after a crisis, such as that generated by COVID-19, people's levels of happiness and the propensity for…
Abstract
Purpose
This study aims to analyze the relationship between expectations of change after a crisis, such as that generated by COVID-19, people's levels of happiness and the propensity for pro-sustainable behavior.
Design/methodology/approach
Surveys were conducted using 1,130 observations. The aim was to measure expectations of change during the pandemic. Furthermore, the relationship between these expectations, happiness levels, and attitudes towards sustainability was analyzed for various elements of daily life. Statistical techniques such as principal component analysis (PCA), cluster analysis, variance analysis and correlation analysis were utilized to explore the underlying patterns and relationships.
Findings
Optimistic expectations for post-pandemic change are associated with a greater likelihood of engaging in environmentally beneficial behaviors, leading to higher levels of life satisfaction. This correlation is particularly significant when individuals envision broader transformations in the collective behavior of humanity. These findings suggest a strong link between beliefs in positive societal transformations and both pro-environmental actions and personal well-being.
Research limitations/implications
The unique circumstances of the pandemic, characterized by heightened media consumption, likely influenced the expectations of individuals, particularly fostering pessimistic outlooks in critical situations. Clear and solid variables were utilized despite not employing validated scales to measure expectations. However, it has been proven that there is a clear link between change expectations, happiness, and the propensity for a more sustainable daily life.
Practical implications
This study identifies guidelines that strengthen brands' communication strategies based on individuals' sustainability profiles and visions of the future.
Social implications
There is a need to target skeptical, change-resistant segments of the population with a more convincing and solid discourse to promote sustainable consumption and behavior.
Originality/value
This is the first study to simultaneously address the relationship between individuals' expectations of change following traumatic events such as the pandemic, their engagement in sustainable behavior, and their increased levels of happiness.
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The purpose of this study is to compare the competition and productivity of the US freight rail transportation industry for the past 41 years (1980 ∼ 2020), which consists of the…
Abstract
Purpose
The purpose of this study is to compare the competition and productivity of the US freight rail transportation industry for the past 41 years (1980 ∼ 2020), which consists of the two periods, before and after the abolishment of the Interstate Commerce Commission (ICC) in 1995.
Design/methodology/approach
This study investigates any relationships between the market concentration index values and labor productivity values in the separate two periods, and how the existence of a regulatory body in the freight transportation market impacted the productivity of the freight rail transportation industry by using a Cobb–Douglas production function on annual financial statement data from the US stock exchange market.
Findings
This study found that, after the abolishment of the ICC: (1) the rail industry became less competitive, (2) even if the rail industry had an increasing labor productivity trend, there was a strong negative correlation between the market concentration index and labor productivity and (3) the rail industry’s total factor productivity was decreased.
Originality/value
This study is to find empirical evidence of the effect of the ICC abolishment on the competition and productivity levels in the US freight rail transportation industry using a continuous data set of 41-year financial statements, which is unique compared to previous studies.
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Xuebing Dong, Hong Liu, Nannan Xi, Junyun Liao and Zhi Yang
This study explores whether and how four main factors of short-branded video content (content matching, information relevance, storytelling and emotionality) facilitate consumer…
Abstract
Purpose
This study explores whether and how four main factors of short-branded video content (content matching, information relevance, storytelling and emotionality) facilitate consumer engagement (likes, comments and shares), as well as the moderating effect of the release time (morning, afternoon and evening) in such relationships.
Design/methodology/approach
This study uses Python to write programs to crawl relevant data information, such as consumer engagement and short video release time. It combines coding methods to empirically analyze the impact of short-branded video content characteristics on consumer engagement. A total of 10,240 Weibo short videos (total duration: 238.645 h) from 122 well-known brands are utilized as research objects.
Findings
Empirical results show that the content characteristics of short videos significantly affected consumer engagement. Furthermore, the release time of videos significantly moderated the relationship between the emotionality of short videos and consumer engagement. Content released in the morning enhanced the positive impact of warmth, excitement and joy on consumer engagement, compared to that released in the afternoon.
Practical implications
The findings provide new insights for the dissemination of products and brand culture through short videos. The authors suggest that enterprises that use brand videos consider content matching, information relevance, storytelling and emotionality in their design.
Originality/value
From a broader perspective, this study constructs a new method for comprehensively evaluating short-branded video content, based on four dimensions (content matching, information relevance, storytelling and emotionality) and explores the value of these dimensions for creating social media marketing success, such as via consumer engagement.
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Lakshman Sondhi, Rakesh Kumar Sahu, Shubhankar Bhowmick and Royal Madan
The purpose of this study was to perform thermo-mechanical deformation and stress analysis in a functionally graded (FG) hollow cylinder considering steady-state temperature…
Abstract
Purpose
The purpose of this study was to perform thermo-mechanical deformation and stress analysis in a functionally graded (FG) hollow cylinder considering steady-state temperature distribution under the effect of rotation, gravity and constant heat generation.
Design/methodology/approach
Navier's equation was used to solve the problem, and the obtained results were validated with benchmarks found to be in excellent agreement. The variation of temperature and other material properties such as Young's modulus, density, thermal expansion coefficient and thermal conductivity varied radially as per power-law variation.
Findings
The effect of rotation was found to be vital compared to gravity and heat generation when compared individually and in combination. The results of displacement and stresses were presented for varying grading indices.
Practical implications
FG cylinders have huge industrial applications as it opens the possibility of developing structures with a high strength/weight ratio. The present study will benefit industries in identifying the effective grading index that can be used by industries for fabricating FG structures.
Originality/value
The effect of rotation, body force and heat generation on a cylindrical body has not been studied before. Furthermore, the combined effect of rotation, body force and heat generation has been studied to understand the behaviour of cylinders operating under similar conditions.
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Nahid Izadpanah Mehrkish and Susan B. Grant
Researchers have long been interested in how the psychology of senior managers affects their behaviours. This paper aims to present the results of a questionnaire into how…
Abstract
Purpose
Researchers have long been interested in how the psychology of senior managers affects their behaviours. This paper aims to present the results of a questionnaire into how positive self-image influences how well senior managers in UK manufacturing organisations support the implementation of management information system (MIS). This study developed two scales, one to measure senior managers’ attitudes and the other to measure support of MIS implementation. It also sought to investigate the impact of senior managers’ positive self-image on their support of MIS implementation in UK manufacturing organisations.
Design/methodology/approach
The authors tested the hypotheses on a data set of 400 senior managers from UK manufacturing organisations. Two unidimensional scales to measure senior managers’ attitude and support level towards MIS implementation were developed. Exploratory factor analysis (EFA) was used to validate the scales. The study also examined the impact of senior managers’ positive self-image on their attitude and support from the perspective of UK manufacturing organisations by using structural equation modelling.
Findings
The study found that senior managers’ positive self-image is a significant contributing factor to their attitude. Also, senior managers’ attitude has a strong positive impact on their support in the MIS implementation process. A strong mediating relationship was found to exist between senior managers’ positive self-image and support through their attitude towards MIS implementation.
Originality/value
Although past literature has examined the importance of senior managers’ attitude and support in successful MIS implementation, there has been no specific scale around management support and attitude towards MIS implementation developed to date. Thus, a contribution of this study is its development of two new scales based on a survey of senior managers of UK manufacturing organisations. The scales can be used to evaluate senior managers’ perception towards MIS implementation and the support they are willing to give whilst implementing MIS. Another contribution of this study is the analysis of positive self-image via item-parcelling which improves model efficiency and provides more stable estimates of the construct.
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