• Advances in concrete construction
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• v.7 no.3
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• pp.191-201
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• 2019

Bamboo concrete bond behaviour is investigated through pullout test in this work. The bamboo strip to be used as reinforcement inside concrete is first treated with chemical adhesive to make the bamboo surface impermeable. Various surface coatings are explored to understand their water repellant properties. The chemical action at the bamboo concrete interface is studied through different chemical coatings, sand blasting, and steel wire wrapping treatment. Whereas mechanical action at the bamboo concrete interface is studied by developing mechanical interlock. The result of pullout tests revealed a unique combination of surface treatment and grooved bamboo profile. This combination of surface treatment and a grooved bamboo profile together enhances the strength of bond. Performance of a newly developed grooved bamboo strip is verified against equivalent plain rectangular bamboo strip. The test results show that the proposed grooved bamboo reinforcement, when treated, shows highest bond strength compared to treated plain, untreated plain and untreated grooved bamboo reinforcement. Also, it is observed that bond strength is majorly influenced by the type of surface treatment, size and spacing of groove. The changes in bamboo-concrete bond behavior are observed during the experimentation.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.4
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• pp.225-235
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• 2015

Treatments for asthma are largely pharmaceutical, with some therapies also utilising alternative breathing techniques. The objective of both medical and alternative methods is to relax contracted airway smooth muscle (ASM). In normal subjects, tidal breathing- and deep inspiration-oscillations are believed to have a bronchodilatory effect. Similarly, application of length oscillations to isolated, contracted ASM also elicits muscle relaxation. As a means of investigating more-effective alternative treatment methods for contracted airways, we analyse the combined effects of bronchodilators and length oscillations on isolated, contracted ASM. The contractile state of the muscle tissue prior to treatment is of primary interest. Thereafter, the effect of applying a combination of small superimposed length oscillations with tidal breathing-like oscillations to ASM is studied alone and in combination with a common bronchodilator, isoproterenol (ISO). This work suggests that relaxation of isolated, contracted ASM following application of combined oscillations and ISO is larger than treatments of either combined oscillations or ISO alone. Further, the observed oscillation-associated relaxation is found to be amplitude- rather than frequency-dependent. This study gives additional insight into the role of oscillations and bronchodilators on contracted airways.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.656-663
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• 1990

To investigate the optimum design conditions of Stirling Engines at the preliminary design stage, comparative study between adoabatoc analysis based on an approximate analytical solution to the Ideal Adiabatic Model and the existing isothermal analysis has been carried out. The optimum phase angle obtained from adiabatic analysis to achieve the maximum work with given combination of design parameters is greater than that from isothermal analysis, while the optimum swept volume ratio is smaller. Effect of variation in the temperature ratio on the work parameter is proved to be stronger in adiabatic analysis. On the contrary, the work parameter by adiabatic analysis is less sensitive to a change in the dead volume ratio. Especially in adiabatic analysis there exists the optimum dead volume ratio maximizing the work parameter, which may provide a lower limit of it. Considering that the adiabatic model is more reasonable, signifiant differences between two methods lead to the conclusion that adiabatic analysis is preferable to isothermal one for the preliminary design of Stirling Engines.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1179-1182
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• 2011

In the present work, successful implementation of ultrasound irradiations for the rapid synthesis of 1,5-benzodiazepine derivatives under solvent-free conditions is demonstrated. Use of a novel catalyst i.e. camphor sulphonic acid in combination with ultrasound technique is reported for the first time. Comparative study for the synthesis of 1,5-benzodiazepines using conventional as well as ultrasonication method is discussed.

• Journal of Korean Academy of Nursing
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• v.34 no.7
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• pp.1307-1314
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• 2004

Purpose: The purpose of this study was to identify the factors influencing Symptoms of Stress among hospital staff nurses. Method: Data was collected by questionnaires from 249 hospital staff nurses in three General Hospital. The data were analyzed using descriptive statistics, pearson correlation coefficients, and stepwise multiple regression. Results: The score of the symptoms of stress showed a significantly positive correlation with the score of work stress(r=.22, p=.00). The symptoms of stress showed a significantly negative correlation with the score of social support(r=-.28, p=.00), self efficacy(r=-.31, p=.00), and hardiness(r=-.24, p=.00). The most powerful predictor of symptoms of stress was social support and the variance explained was $16\%$. A combination of social support, ways of coping, and work stress account for $32\%$ of the variance in symptoms of stress among hospital staff nurses. Conclusion: This study suggests that social support, ways of coping, self efficacy, hardiness, and work stress are significantly influencing factors on symptoms of stress among hospital staff nurses.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.247-250
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• 2009

Awareness of resource conservation and pollution prevention has been continually increasing. The proven benefits from CFRP's unique combination of light weight and high strength compare to conventional material is well suited for minimizing fuel consumption during vehicle in particular rail operation. Responding the awareness, this work intends to study CFRP's recycling method that is not only technical performance but also environmental view point. According to prior work of technical performance test, this work aims at quantifying the footprint of energy and GHG derived from the two appreciated performance of pyrolysis and acids recycling methods. The streamline LCA is the concept for systematic assessment. The boundary is scoped at the recycling activity, consequently, the data in and out from the specific target activity are obtained under the gate to gate data collection. Its function is recovery carbon fiber. To count and compare function, functional unit is set at 60% of recycling rate. Korea database is mainly source for acquiring the footprint of both. The numerical results presented that the energy footprint of acids and pyrolysis is 164.95 and 1,199.88 MJ-eq., respectively. Meantime, the GHG footprint of is 1,196.22 and 5,916.08 g CO2 eq. for acids and pyrolysis. In summary, the acids recycling method is, in regarding the environmental performance, better than pyrolysis recycling method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.271-272
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• 2021

The maintenance and repair work of sidewalk block pavement is a construction that requires a large amount of budget to be invested every year. It is important to establish an appropriate standards for estimating construction cost to ensure proper budgeting and quality. In this study, the standards for estimating the cost of maintenance and construction work for sidewalk blocks that can be applied to the construction volume classified according to the site conditions, construction type, and equipment use differentiated from new construction was established. As a result, the daily construction volume was presented by reflecting excavator and truck as equipment in the combination of paver and common worker. The re-installation was applied by separating the construction volume of sections with general blocks and induction/raised blocks based on the installation of sidewalk blocks after demolition. Generally if block cutting is necessary, the precision construction conditions using a cutting machine were taken into consideration to secure the construction quality. In addition, it has been revised to apply classified construction volume into A and B-Type depending on the park and site conditions.

• KIEAE Journal
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• v.12 no.6
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• pp.77-84
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• 2012

The current architectural design of unit modular has been based on 2D of CAD program, so unit modular character which needs unit information management, as a dried-member system, has no effect on design process. The purpose of this study is We have developed a suitable BIM design process, according to various works of construction, then tried to contribute to supply and activation of the urban-life-housing based on unit modular. The BIM modeling process based on unit modular has been in order of unit combination with preparing manual classification, and, it has been constructed, at construction site, from housing foundation to roof finish by Bottom-up method. At a manufacturing factory, it has been produced in order of 1) grouping materials and parts, 2) fabricating unit boxes, and 3) interference examination of unit boxes, and each order has been classified as housing structure, architecture, plumbing process separately. At a construction site, the fabrication has been done in order of, like as a real housing construction scenario, 1) RC foundation work 2) unit module job-site-fabrication work, 3) roof truss work, 4) plumbing and HVAC work, and 5) housing interior finish work. After modeling process, the interference examination on each work of construction has finally completed modeling. The Unit modular utilizing BIM modeling can make easy housing maintenance through systematic control with preparing manual of unit module information, and securing accurate and speedy construction information. And it will promote design credibility and create maximum effect of unit modular construction method, such as construction period reduction and upgrade of construction quality, etc., through the computer simulation as real as construction environment in cyber space, and with the interfering examination.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.459-467
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• 2013

Objective: The aim of this study is to review the studies on job rotation with various points of view and to classify the studies considering the approach methods. Background: Various work interventions were carried in order to prevent the work-related musculoskeletal disorders(WMSDs) and job rotation was considered as one of the simple and effective methods. Method: Previous studies were systematically collected with the combination of keywords such as job, task, rotation, allocation, line balancing, etc. Collected studies were classified into three categories: field study, laboratory study and optimization approach study. Results: Field studies showed that most studies focused on the evaluation of the factors causing the musculoskeletal disorder. Moreover, the effect of job rotation could be hard to identify because it required a long-period close observation. Laboratory studies covered only simple aspects of tasks or movements. Optimization approach studies showed the systematic approach to establish the job rotation scheme though many limitation and assumptions were adopted. Conclusion: This study collected and classified the previous studies on job rotation and presented the different approaches across various research areas. Application: The results of this study could help the practitioner and ergonomist how to establish the job rotation scheme.

• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.554-560
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• 2006

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.