• 한국농공학회논문집
• /
• 제47권3호
• /
• pp.29-37
• /
• 2005

This study was carried out to file up structural design data for optimizing Pleurotus eryngii growing houses. Design data are including current farm status of Pleurotus eryngii growing houses in the aspect of structural configuration as well as environmental conditions to be controlled and maintained inside. A structural analysis was performed for the on-farm structures as well as some structures modified and suggested through field survey and analysis. The results are summarized as follows. According to the results of status analysis, Pleurotus eryngii growing houses were categorized as arch-roofed simple type and sandwich panel type. Though the size of Pleurotus eryngii cultivation facilities were considerably diverse, the basic dimensions of Pleurotus eryngii cultivation facilities showed relatively similar pattern: more or less of 20m of length, $6.6\~7.0m$ of width, $4.6\~5.0m$ of peak height, $1.2\~1.6m$ of bed width, and 4 layers of bed. In the aspect of spatial use of cultivation facilities, suggested models were shown to be mostly reasonable in the aspect of heating and cooling, micro-meteorological stability, land use efficiency per unit floor area, etc.. Especially, the standard models suggested so far were thought to be not efficient in its surface area and spatial volume per unit floor area as well as its uneffective structural design in the area around ceiling. In the results of structural analysis for the models suggested through this study by using those section frames to be found on farms, the panel type structures of both single span and double span were estimated to be over designed, whereas arch-roofed pipe houses were mostly found to be under-designed.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.696-700
• /
• 2007

In case of dome-typed gymnastics training floor, since its form takes shape of the focus of sound, in the occasion when the finishing-material was used with the sandwich panel that prominent in reflexibility, and because the reverberation of sound in indoor is too loud, a smooth practice and teaching is very difficult. As this indoor gymnastics training floor, standing at its character, is required simultaneously the idea communication between the player and the coach, and the acoustic capability regarding to the clearness of music, besides the sport activity, the method to minimize the acoustic defect should be urgently contrived from the stages of design and beginning of construction. On this viewpoint, after investigation on the confidence of the surveyed value and the estimated value using acoustic simulation, and use of the changed finish-material, this thesis intends to design the dome-typed gymnastics training floor that secured the optimized acoustic condition. It is also considered that such result of the study could be utilized as the useful data that enables to improve the retrenchment effect of the construction cost as well as the acoustic performance, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2011년도 제37회 추계학술대회논문집
• /
• pp.938-941
• /
• 2011

이 논문은 에그-박스 코어의 등간 전단 탄성계수에 대해 다루고 있다. 코어의 등가 전단 탄성계수를 얻는 방법으로 유한요소해석, 수치 해석, 실험이 있다. 이번 연구에서는 에그-박스 코어의 등가 전단 탄성계수를 평가하기 위하여 3점 굽힘 시험을 수행하였으며, 그 결과로부터 상온에서의 에그-박스 코어의 등가 전단 탄성계수를 획득하였다. 이 결과를 유한요소해석으로부터 얻어진 결과와 비교하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.447-448
• /
• 2009

본 논문에서는 과산화수소($H_2O_2$) 분해 반응을 이용, 이산화망간($MnO_2$) 및 탄산수소나트륨($NaHCO_3$)을 촉매제로 사용하여 콘크리트 기포발생 유도를 극대화 하였다. 또한 기포콘크리트 초경량화를 이루기 위한 최적배합 도출 및 소요강도 확보 등의 다양한 실험을 통해 경량기포콘크리트의 물리적 역학적 특성을 알아보았다. 실험결과 전반적으로 KS F 4039 및 KS F 2459규정에 있는 품질기준에 충분히 만족하는 결과를 보였다.

• 한국소음진동공학회논문집
• /
• 제25권6호
• /
• pp.432-439
• /
• 2015

In order to reduce the structure borne noise of the equipment sufficiently, its exciting force should be restricted and additional anti-vibration devices such as resilient mount and bellows should be applied. Since the structure borne noise is dependent on the design of the base for the equipment, it is very important to design the base with low vibration. Therefore, in this research, various types of the base design for the shipboard equipment are investigated to reduce the structure borne noise. In order to design the base with low vibration, the exciting force at the center of the gravity of the equipment is firstly defined through the experiment. Using the exciting force identified by experiments, various types of base designs for the typical turbo machine are evaluated by FEM(finite element method) analysis.

• 한국산업융합학회 논문집
• /
• 제10권2호
• /
• pp.73-80
• /
• 2007

The preparation of oil absorbent using waste polyurethane was studied. And the effects of shape, size, and contents of waste polyurethane foam was investigated. The waste foam was treated in shape of powder, cube and bar type generated from rigid sandwich panel process. The tests for flexural strength, combustibility, and water absorptivity were carried out to investigate the mechanical and physical properties of the recycled foams. And the cell microstructure was evaluated through Scanning Electron Micrograph. The recycled foam containing powder-shaped underfilled and showed poor properties that was generated through reactivity of the resins and increasing of slurry viscosity. For the recycled foam with the cube and bar-shaped, the underfilling was caused by interference between the waste PUFs and increasing surface areas of PUF. Low cell density, non-uniformity of cell shape and size, and low adhesion of the boundary surface (new/recycled) was showed as a result of the poor properties. Considering underfilling and the properties of PUF (new/recycled), maximum recycle contents were less than 20 wt% for the powder and above 40 wt% for the cube and bar.

• 복합신소재구조학회 논문집
• /
• 제2권3호
• /
• pp.12-17
• /
• 2011

본 논문은 노후교량바닥판 대체용으로서 하이브리드 GFRP-강재 바닥판의 휨거동을 구조적 거동특성을 기술하고 있다. 하이브리드 GFRP-강재 바닥판의 구조적 특성을 조사하기 위해 정적하중의 실험적 연구를 수행하였다. 하이브리드 바닥판의 파괴모드는 초기항복을 지나서 연성거동을 나타내었다. 결과는 유한요소프로그램 ANSYS의 값과 비교하였다. 제안된 하이브리드 바닥판이 교량적용에 유용함을 확인하였다. 하이브리드 바닥판의 두께는 유사한 휨 강성을 갖는 완전복합신소재 바닥판께와 비교하였을 때 감소될 수 있었다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권8호
• /
• pp.95-102
• /
• 2020

The purpose of this study is to test both the alignment theory and entertainment theory on family firms listed on the Pakistan Stock Exchange. To achieve these goals, we collected secondary data from 164 non-financial family firms in various sectors during 2014-18. These family firms are classified into two categories: family control firms and family owned firms. We take the audit fee and the audit quality as dependent variables while family control firms, family-owned firms, and family CEOs as independent variables. In addition, the study uses leverage, profit and export as control variables. To test the effect of the explanatory variables on the output variables, we use two econometric models, Ordinary Least Square and the Probit regression model. In addition, Huber Sandwich test is used to check the non-normality and heteroscedasticity of panel data. Contrary to the alignment effect, the study supports the entrenchment effect and advocates that family-controlled firms as well as family-owned firms are not conscientious regarding the selection of external auditors during their contracts with audit firms. They are less likely to pay high audit fees for good quality audit in Pakistan. Furthermore, the study shows a statistically significant and positive relationship between audit quality and audit fees.

• 대한기계학회논문집A
• /
• 제31권2호
• /
• pp.245-252
• /
• 2007

Since the new millennium, truss PCMs(Periodic Cellular Metals) have drawn attention because of their superior specific stiffness, strength and multi-functionality. Prior studies have focused on the structural design and optimization. Kagome truss PCM has been proved to have the higher resistance to plastic buckling, more plastic deformation energy and lower anisotropy than other truss PCMs. In this study, we introduce a new idea to fabricate multi-layered Kagome truss PCM from continuous wires which can gain high strength as in piano wires and can be controlled to be defect free owing to drawing process. The relative density, the stiffness and the strength under bending and compressive load are estimated through elementary mechanics and compared with the results from experiments and FEA. The failure mechanisms are analyzed, and also mechanical performance and production are discussed.

• 콘크리트학회논문집
• /
• 제25권4호
• /
• pp.381-388
• /
• 2013

이 연구는 플레이트의 추가가 중단열 외벽 시스템과 같은 얇은 콘크리트 패널에 설치되는 단일 앵커 콘크리트의 파괴 강도에 미치는 영향을 평가하였다. 탄성론 기반의 단순화된 해석모델을 이용하여 CCD(concrete capacity design)이론을 통해 나타난 콘크리트 파괴 강도에 대한 플레이트의 휨 응력을 예측하였으며, 실험을 통해 나타난 플레이트의 휨 응력과 비교하였다. 앵커의 콘크리트 파괴 강도에 대한 실험은 100 mm의 얇은 패널을 대상으로 수행되었으며, 플레이트의 크기는 플레이트의 휨 응력과 항복 응력이 가장 근사값을 갖는 $PL130{\times}9mm$를 기준으로 계획되었다. 실험 결과를 통해, 플레이트의 너비 또는 두께 증가에 의해 콘크리트 파괴 강도는 향상되는 것으로 나타났지만, 콘크리트 파괴 강도의 향상 수준은 지속적으로 감소하는 것으로 나타났다. 또한, 탄성론 기반의 단순화된 탄성해석모델을 이용하여 해석과 실험 결과를 비교했을 때, 콘크리트 파괴 강도에 대한 플레이트의 영향을 비교적 잘 부합하는 것으로 나타났다.