• Title/Summary/Keyword: Environmental performance

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A Job Stress Model of Workers in Fashion and Textile Industries (섬유패션기업 종사자의 직무스트레스 모델)

  • Park, Kwang-Hee;Yoo, Hwa-Sook
    • Fashion & Textile Research Journal
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    • v.7 no.1
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    • pp.33-40
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    • 2005
  • This study is to develope the job stress model for workers in fashion and textile industries and to investigate the effect of job stressors on stress symptom and its effect on job performance. The structural equation model analysis was performed for examining the relationship among job stressors, stress symptom and job performance. Environmental factors, task factors, role factors and organizational climate factors were identified as job stressors. Task characteristics and role characteristics were positively related to job stress symptom. Environmental factors and organizational climate factors were negatively related to job stress symptom. Also, job stress symptom was negatively related to job performance. The findings suggest some implications on how to improve job performance or to reduce job stress.

Use of SMA bars to enhance the seismic performance of SMA braced RC frames

  • Meshaly, Mohamed E.;Youssef, Maged A.;Abou Elfath, Hamdy M.
    • Earthquakes and Structures
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    • v.6 no.3
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    • pp.267-280
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    • 2014
  • Shape Memory Alloy (SMA) braces can be used to reduce seismic residual deformations observed in steel braced Reinforced Concrete (RC) frames. To further enhance the seismic performance of these frames, the use of SMA bars to reinforce their beams is investigated in this paper. Three-story and nine-story SMA-braced RC frames are designed utilizing regular steel reinforcing bars. Their seismic performance is examined using twenty seismic ground motions. The frames are then re-designed using SMA reinforcing bars. Different design alternatives representing different locations for the SMA reinforcing bars are considered. The optimum locations for the SMA bars are identified after analysing the design alternatives. The seismic performance of these frames has indicated better deformability when SMA bars are used in the beams.

Construction quality issues in performance-based wind engineering: effect of missing fasteners

  • van de Lindt, John W.;Dao, Thang Nguyen
    • Wind and Structures
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    • v.13 no.3
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    • pp.221-234
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    • 2010
  • In light-frame wood construction, missing roof-sheathing fasteners can be a relatively common occurrence. This type of construction makes up the vast majority of the residential building stock in North America and thus their performance in high winds, including hurricanes, is of concern due to their sheer number. Construction quality issues are common in these types of structures primarily because the majority are conventionally constructed and unlike steel and reinforced concrete structures, inspection is minimal except in certain areas of the country. The concept of performance-based wind engineering (PBWE), a relatively new paradigm, relies on the assumption that building performance under wind loads can be accurately modeled. However, the discrepancy between what is designed (and modeled) and what is built (the as-built) may make application of PBWE to light-frame wood buildings quite difficult. It can be concluded from this study that construction quality must be controlled for realistic application of PBWE to light-frame wood buildings.

A Study on the Environmental Degradation Factors and the Required Performance of the Waterproofing Materials Applied to Underground Structures in Residential Apartment Buildings- Survey Centered- (공동주택 지하구조물에 적용되는 방수재의 환경적 열화요인과 부위별 필요성능에 관한 연구-설문조사를 중심으로-)

  • An, Ki-Won;Kang, Hyo-Jin;Oh, Kyu Hwan;Kim, Soo-Yeon;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.213-214
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    • 2017
  • In this study, a survey was conducted to investigate the environmental degradation factors of specific areas in residential apartment underground structures an'd the required performance attributes for waterproofing material. Based on the survey, it was concluded that joint displacement of concrete is the highest cause for problems, and the required performance was determined to high wet surface adhesion performance for waterproofing materials.

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The Effect of Exhaust System Components on the Sl Engine Performance (배기구성요소가 SI기관의 성능에 미치는 영향)

  • Park Kyoungsuk;Park Sejong;Son Sungman
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.6 s.171
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    • pp.192-198
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    • 2005
  • Recently, Automobile manufacturers regarding stability, economic environmental-friendly problems by the development of automobile. This reason is increasingly strict environmental regulations to lower fuel consumption and reduce emission. Designing more efficient and low emission control exhaust system results in more efficient Performance, reduced back Pressure and higher convert efficiency. Also to reduce the noise and the vibration of the automobile. According to develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption rate, higher conversion efficiency demand information of pressure fraction and heat characteristics. To be able to determine these factor fur we experiment on each case of exhaust system unit. In this study, how back pressure is distributed in flow-through in exhaust system and how to design exhaust system flexibleness, efficiency, lower back pressure and optimal performance. This study furnish basic data for engineers, technicians.

Performance Analysis of Bridge using Structural Health Monitoring: Seong-Su Bridge Case-study

  • Kaloop, Mosbeh R.;Ban, Woo Hyun;Hu, Jong Wan
    • Journal of Urban Science
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    • v.8 no.1
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    • pp.1-6
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    • 2019
  • The performance evaluation of existing structures is important to study the safety of those structures with changing the loads over the lifetime of structures. Therefore, this study aims at evaluating the Seong-Su bridge, Seoul, Korea, using structural health monitoring (SHM) system. The static and dynamic tests are used to assess the behavior of the bridge. The statistical and wavelet analyses are used to demonstrate the behavior of the bridge in the time and frequency domains. The previous SHM results are used to assess the bridge performance. The results of this study show that the bridge performance under static and dynamic loads is safe in time and frequency domains.

Modification of EPDM Rubbers for Enhancement of Environmental Durability of Aerator Membrane (산기관용 멤브레인 고무판의 환경내구성 향상을 위한 EPDM 고무의 개질)

  • Ahn, Won-Sool
    • Journal of Environmental Science International
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    • v.17 no.1
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    • pp.107-112
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    • 2008
  • A study on the enhancement of environmental durability of EPDM rubber materials for the aerator membrane was performed using a butyl rubber as a modifier. A conventional EPDM rubber formulation was evaluated as having about 26.0 wt% or more oil content from the chloroform immersion test. These oils would be gradually and continuously deleted from the aerator membrane when directly exposed to a waste-water or chemically corrosive fluids, making the membrane less flexible and the performance worse. To improve this, a butyl rubber (IIR) was utilized as the modifier for a low-ENB type of EPDM rubber formulation with low-oil content. The environmental durability of the IIR-modified EPDM rubber material was expected to be greatly enhanced compared to the conventional one. However, the mechanical and performance properties such as elongation, tensile strength, and air bubble size, etc. were still maintained as good as in the conventional one. Furthermore, TGA analysis of the IIR-modified EPDM material showed that there would be partially compatible between IIR and EPDM. It also showed that the initial degradation temperature of the IIR-modified EPDM could be somewhat increased, exhibiting the enhanced compatibility among the components and, thereby, more enhanced environmental durability.

Treatment of cutting-oily wastewater by electrocoagulation-flotation (ECF) process: Modeling approach

  • Chawaloesphosiya, Nattawin;Mongkolnauwarat, Jittrapa;Prommajun, Chayanin;Wongwailikhit, Kritchart;Painmanakul, Pisut
    • Environmental Engineering Research
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    • v.20 no.4
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    • pp.392-396
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    • 2015
  • This work aims to investigate the oily wastewater treatment by the electrocoagulation-flotation (ECF) and propose a mathematical model for the efficiency prediction. Cutting oil was used to prepare the synthetic oily wastewater with submicron droplet sizes. The chemical coagulation by aluminium sulfate was firstly tested following by the electrocoagulation-flotation with aluminium electrodes. Both processes gave the effective treatment performance with the efficiencies higher than 90%. However, the ECF consumed less aluminium dosage as well as produced less sludge, which were its advantage on the chemical coagulation. The performance of the ECF was found to be affected by the current density, oil concentration, and reaction time according to the analysis by the design of experiment (DOE). Finally, the prediction model was proposed by two approaches, including linear and logarithm function. The latter model gave more accuracy prediction results in terms of treatment efficiency and duration in the lag and stable stages.

Comparative Sustainability Analysis of Two Asian Cities: A Multidimensional Assessment of Taipei and Almaty

  • Shmelev, Stanislav E.;Sagiyeva, Rimma K.;Kadyrkhanova, Zhanar M.;Chzhan, Yelena Y.;Shmeleva, Irina A.
    • The Journal of Asian Finance, Economics and Business
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    • v.5 no.3
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    • pp.143-155
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    • 2018
  • The article compares economic and environmental performance of Taipei and Almaty from the point of view of "green" economy, which is able to act as a key tool to ensure sustainable development of the region. As the comparison of the parameters of ecological and economic development of the Taipei and Almaty cities shows, they are similar in population size, but demonstrate completely different trends of sustainable development. Economic performance of the Taipei city is achieved with a decrease in the consumption of natural resources and the production of pollution, while the situation in Almaty is the opposite. Almaty maintains a high level of air pollution due to the use of coal in electricity production, as well as increased traffic and density of construction, including the southern part of the city, which is a zone for the transit of mountain air flows. The article discusses the activities jointly conducted by the Government of Taiwan and non-governmental organizations on environmental issues, as well as environmental NGOs, which resulted in significant improvements in the environmental field. Measures to stimulate the development and implementation of environmental innovations applied in the field of sustainable development in the city of Taipei can be adapted for the city of Almaty, where the environmental situation deteriorates year by year.

Comparison Analysis of Machine Learning for Concrete Crack Depths Prediction Using Thermal Image and Environmental Parameters (열화상 이미지와 환경변수를 이용한 콘크리트 균열 깊이 예측 머신 러닝 분석)

  • Kim, Jihyung;Jang, Arum;Park, Min Jae;Ju, Young K.
    • Journal of Korean Association for Spatial Structures
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    • v.21 no.2
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    • pp.99-110
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    • 2021
  • This study presents the estimation of crack depth by analyzing temperatures extracted from thermal images and environmental parameters such as air temperature, air humidity, illumination. The statistics of all acquired features and the correlation coefficient among thermal images and environmental parameters are presented. The concrete crack depths were predicted by four different machine learning models: Multi-Layer Perceptron (MLP), Random Forest (RF), Gradient Boosting (GB), and AdaBoost (AB). The machine learning algorithms are validated by the coefficient of determination, accuracy, and Mean Absolute Percentage Error (MAPE). The AB model had a great performance among the four models due to the non-linearity of features and weak learner aggregation with weights on misclassified data. The maximum depth 11 of the base estimator in the AB model is efficient with high performance with 97.6% of accuracy and 0.07% of MAPE. Feature importances, permutation importance, and partial dependence are analyzed in the AB model. The results show that the marginal effect of air humidity, crack depth, and crack temperature in order is higher than that of the others.