• Structural Engineering and Mechanics
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• 제76권5호
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• pp.561-578
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• 2020

The present work addresses the surface integrity and chip morphology in finish hard turning of AISI D3 steel under nanofluid assisted minimum quantity lubrication (NFMQL) condition. The surface integrity aspects include microhardness, residual stress, white layer formation, machined surface morphology, and surface roughness. This experimental investigation aims to explore the feasibility of low-cost multilayer (TiCN/Al2O3/TiN) coated carbide tool in hard machining applications and to assess the propitious role of minimum quantity lubrication using graphene nanoparticles enriched eco-friendly radiator coolant based nano-cutting fluid for machinability improvement of hardened steel. Combined approach of central composite design (CCD) - analysis of variance (ANOVA), desirability function analysis, and response surface methodology (RSM) have been subsequently employed for experimental investigation, predictive modelling and optimization of surface roughness. With a motivational philosophy of "Go Green-Think Green-Act Green", the work also deals with economic analysis, and sustainability assessment under environmental-friendly NFMQL condition. Results showed that machining with nanofluid-MQL provided an effective cooling-lubrication strategy, safer and cleaner production, environmental friendliness and assisted to improve sustainability.

• 디지털산업정보학회논문지
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• 제14권2호
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• pp.117-131
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• 2018

This study analyzed the personal characteristics of the SW industry workers and investigated how these individual characteristics affect the satisfaction of job satisfaction. In addition, we examined how satisfaction with these jobs varies according to satisfaction with internal control and external compensation. This study surveyed the employees of SW industry in Seoul and Daegu from September 15 to October 15, 2017. The results of this study are as follows. First, personal characteristics have a significant effect on job satisfaction. Second, extroversion, openness, friendliness and integrity have a significant effect on job satisfaction. This is consistent with the previous study (Park and Song, 2005), which suggests that people with extroversion are more likely to feel positive emotions such as joy. In addition, it is believed that open empathy has a tendency to share with others in work, and positive emotions in work have a significant influence because they show high achievement in work. A friendly person places great importance on a comfortable and harmonious relationship with others, so he builds and maintains good relationships with the members of the organization by trusting others in the organization. Third, nervousness showed no significant effect on job satisfaction. This is consistent with the previous study (Yoo, 1987) in which the more nervousness is, the more unpleasant emotions work and the more negative emotions and negative experiences occur. Fourth, personal characteristics have positive effects on job satisfaction in the moderating effects of intrinsic compensation and external compensation. There is a difference in job satisfaction due to intrinsic compensation and external compensation.

• 한국공간구조학회논문집
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• 제23권2호
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• pp.19-28
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• 2023

Timber structures are susceptible to moisture, contamination, and pest infestation, which can compromise their integrity and pose a significant fire hazard. Despite these drawbacks, timber's lightweight properties, eco-friendliness, and alignment with current architectural trends emphasizing sustainability make it an attractive option for construction. Moreover, timber structures offer economic benefits and provide a natural aesthetic that regulates building temperature and humidity. In recent years, timber domes have gained popularity due to their high recyclability, lightness, and improved fire resistance. Researchers are exploring hybrid timber and steel domes to enhance stability and rigidity. However, shallow dome structures still face challenges related to structural instability. This study investigates stability problems associated with timber domes, the behavior of timber and steel hybrid domes, and the impact of timber member positioning on dome stability and critical load levels. The paper analyzes unstable buckling in single-layer lattice domes using an incremental analysis method. The critical buckling load of the domes is examined based on the arrangement of timber members in the inclined and horizontal directions. The analysis shows that nodal snapping is observed in the case of a concentrated load, whereas snap-back is also observed in the case of a uniform load. Furthermore, the use of inclined timber and horizontal steel members in the lattice dome design provides adequate stability.

• 치위생과학회지
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• 제10권4호
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• pp.211-218
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• 2010

부산지역 치과를 포함하는 종합병원에 근무하는 병원종사자 228명을 대상으로 치과위생사의 주된 업무, 선호하는 내적인 이미지, 선호하는 외적이미지, 사회적 수준 등에 대하여 조사한 본 연구의 결론은 다음과 같다. 1. 치과위생사의 주된 업무는 1순위는 치의사의 진료보조 28.2%, 2순위 치석제거 23.2%, 3순위 예방업무 20.6%로 나타났다. 2. 선호하는 이미지는 밝은 표정이 61.4%로 가장 많았으며, 단정함 32.9%, 세련됨 3.5%, 지적 임 2.2% 순으로 나타났다. 기혼에서 밝은 표정을 많이 선호하였으며 유의미한 차이를 보였다(${\chi}^2=8.11$, p<.05). 3. 유니폼은 투피스 바지 형을 76.3%로 가장 선호하였으며, 여자에서 투피스 바지 형을 많이 선호하는 유의미한 차이를 보였다(${\chi}^2=41.09$, p<.001). 4. 치과위생사가 갖추어야 할 중요한 자질은 전문적 지식이 49.1%로 가장 많았으며, 성실함과 책임감 23.2%, 친절성 22.4%, 인격과 교양 5.3% 순으로 나타났다. 40세 이상인 종사자가 성 실함과 책임감으로 인식하는 경우가 많았으며 유의미한 차이를 보였다(${\chi}^2=20.62$, p<.01) 5. 사회적 수준이 높다고 인식할수록 치과위생사의 외형적 모습이 신뢰감 또는 안정감에 영향 을 줄 수 있으며 유의미한 차이를 보였다(F=9.98, p<.001) 6. 사회적 수준이 높다고 인식하는 경우 밝은 표정을 선호하였으며(${\chi}^2=31.54$, p<.001), 사회적 수준이 낮다고 인식할수록 경우 친절성 및 성실함과 책임감이라고 인식하였으며, 유의미한 차이를 보였다(${\chi}^2=14.03$, p<.05). 이상의 연구결과를 볼 때 치과위생사의 사회적 수준과 이미지 향상을 위해서는 치과위생사에게 적합한 업무를 수행할 수 있는 실무능력향상 프로그램 마련되어야 할 것으로 사료된다.