scholarly journals Impacts of Material Orthotropy on Mechanical Behaviors of Asphalt Pavements

2021 ◽  
Vol 11 (12) ◽  
pp. 5481
Author(s):  
Miao Lin ◽  
Changbin Hu ◽  
Hongxin Guan ◽  
Said M. Easa ◽  
Zhenliang Jiang

Material anisotropy significantly impacts the mechanical behaviors of asphalt pavements. However, most current asphalt pavement design methods treat the material properties only as isotropic, which could significantly skew the mechanical behaviors. There is a need to evaluate the impact of material anisotropy on pavement mechanical behaviors. In this study, we first developed a new and efficient 3-dimensional finite element (FE) model of anisotropic material. Then, the feasibility of the proposed FE model was verified using field data collected with a falling weight deflectometer. Finally, using this model, the contributions of each layer anisotropy to the mechanical properties were determined. The results showed that the mechanical behaviors were more sensitive to the orthotropy than to the transverse isotropy of the material. The all-layer orthotropy was the most unfavorable combination. In addition, the subgrade orthotropy showed the most significant effect on increasing the surface deflection and compressive strain of the subgrade top (by about 10%). Based on the study results, we recommend that the homogeneity degree of the filling subgrade should be strictly controlled to ensure adequate pavement capacity and anti-rutting performance during construction.

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Alvan H. Wordu ◽  
Kong Fah Tee ◽  
Mahmood Shafiee

Abstract Corrosion damage is reported to be one of the leading causes of steel pipeline failure causing significant financial losses to operators and damage to the surrounding environment. As part of a rising confrontation to pipeline integrity management, researchers are continuously seeking better ways to assist on how to identify, assess, and prevent such incidents. Thus, there is a crucial need to establish a connection between assessment of pipeline condition and its structural stability. To achieve this, a three-dimensional finite element (FE) model is developed. The effects of geometry parameters such as defect thickness and spread angle are considered. Results show that thicker pipelines with corrosion groove perform better structurally than slender equivalents. The impact of corrosion damage is assessed to be significant on pipe stability with pipelines experiencing higher displacement and wall stresses with increasing defect depth and spread angle. A protective measure has been proposed using the buried pipes bedding system. The most critical spread angle is at 60 deg for unprotected pipe sections and 90 deg for bedded protected sections.


Author(s):  
Sang Nguyen Minh

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.


2020 ◽  
Vol 18 (6) ◽  
pp. 1063-1078
Author(s):  
T.N. Skorobogatova ◽  
I.Yu. Marakhovskaya

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.


1995 ◽  
Vol 32 (9-10) ◽  
pp. 197-204
Author(s):  
G. C. Christodoulou ◽  
I. Ioakeim ◽  
K. Ioannou

The paper presents a numerical modeling study aimed at a preliminary assessment of the impact of the planned sea outfall of the city of Limassol, Cyprus, on the waters of Akrotiri bay. First the local meteorological and oceanographic conditions as well as the loading characteristics are briefly reviewed. Two-dimensional finite element hydrodynamic and dispersion models are subsequently applied to the study area. The results of the former show an eastbound flow pattern under the prevailing westerly winds, in general agreement with available field observations. The spread of BOD and N under continuous loading is then examined for eastward as well as for westward flow as an indicator for the extent of pollution to be expected. The computed concentrations are generally low and confined to the shallower parts of the bay.


Author(s):  
Mohinder C. Dhiman ◽  
Abhishek Ghai

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.


2020 ◽  
pp. 003464462097393
Author(s):  
Colin Cannonier ◽  
Monica Galloway Burke ◽  
Ed Mitchell

In this article, we explore the impact of a reentry and aftercare service program on the likelihood of returning to prison by ex-offenders. Using administrative data within a difference-in-differences design, we find that this social program is associated with a reduction in recidivism rates. Benchmark estimates show that the program was associated with estimated reductions in the probability of recidivating of 6.0 to 8.7 percentage points. The estimate appears to be economically significant as it implies an estimated treated effect in the 15.8% to 19.2% range. We consider the heterogeneous effects of the program on reducing recidivism according to race, age group, and program type. The program helped to reduce recidivism among Whites but not Blacks; older participants were the main beneficiaries while the effectiveness of the program was observed among older participants. Back-of-the-envelope cost-savings analysis is incorporated to estimate the potential savings to the state arising from the reduction in recidivism rates likely attributable to the program. The findings are robust to sample selection bias, alternative specifications, and estimation techniques. Our results offer some implications for the role of faith-based social programs within the context of criminal justice reform to combat reentry of former inmates. They also provide a cautionary tale about the need to evaluate programs not just based on their overall effect.


2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich

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.


2020 ◽  
Vol 4 (1) ◽  
pp. 50-58
Author(s):  
Matthias  Tietsch ◽  
Amir Muaremi ◽  
Ieuan Clay ◽  
Felix Kluge ◽  
Holger Hoefling ◽  
...  

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.


2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
A Fernández Candela ◽  
L Sánchez-Guillén ◽  
L García Catalá ◽  
C Curtis Martínez ◽  
M Bosch Ramírez ◽  
...  

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.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
David Hope ◽  
David Kluth ◽  
Matthew Homer ◽  
Avril Dewar ◽  
Richard Fuller ◽  
...  

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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