• International Journal of Korean Welding Society
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• 제4권1호
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• pp.53-60
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• 2004

Adhesive-bonded joints are widely used in the industry. Recently, applications of adhesive bonding joints have been increased extensively in automobile and aircraft industry. The strength of adhesive joints is influenced by the surface roughness, adhesive shape, stress distribution, and etc. However, the magnitude of the influence has not yet been clarified because of the complexity of the phenomena. In this study, as the fundamental research of adhesive bonding joints, the effects of adhesive shape and loading speed on bonding strength properties and durability of aluminum to polycarbonate single-lap joints were studied. To evaluate the effect of adhesive shape, several modified shapes were used, and loading speeds were varied from 0.05 to 5mm/min. As a result, the load distribution showed a brittle fracture tendency. The trigonal edged single lap and bevelled lap joints showed the higher strength than the plain single lap, trigonal single lap, joggle lap and double lap joints in same adhesive area. The fractures of trigonal single lap and trigonal edged single lap joints that had the higher strength level were shown as the mixture type of the cohesive and interfacial-failure, mostly joggle lap joints that had the lower strength level were shown as the adhesive-failure.

• 대한기계학회논문집A
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• 제28권6호
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• pp.783-790
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• 2004

Adhesive-bonded joints are widely used in the industry. Recently, applications of adhesive bonding joints have been increased extensively in automobile and aircraft industry. The strength of adhesive joints is influenced by the surface roughness, adhesive shape, stress distribution, and etc. However, the magnitude of the influence has not yet been clarified because of the complexity of the phenomena. In this study, as the fundamental research of adhesive bonding joints, the effects of adhesive shape and loading speed on bonding strength properties and durability of aluminum to polycarbonate single-lap joints were studied. To evaluate the effect of adhesive shape, several modified shapes were used, and loading speeds were varied from 0.05 to 5 mm/min. As a result, the load-displacement distribution was shown a brittle fracture tendency. The trigonal edged single lap and bevelled lap joints showed the higher strength than the plain single lap, trigonal single lap, joggle lap and double lap joints in same adhesive area. The fractures of trigonal single lap and trigonal edged single lap joints that had the higher strength level were shown as the mixture type of the cohesive and interfacial-failure, mostly joggle lap joints that had the lower strength level were shown as the adhesive-failure.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1264-1276
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• 2000

Light-off catalyst has been used for minimization of cold-start emissions. Improved cold-start performance of light-off catalyst needs the optimal design in terms of flow distribution, geometric surface area, precious metal loading, cell density and space velocity. In this study, these influential factors are numerically investigated using integrated numerical technique by considering not only 3-D fluid flow but also heat and mass transfer with chemical reactions. The present results indicate that uneven catalyst loading of depositing high active catalyst at upstream of monolith is beneficial during warm-up period but its effect is severely deteriorated when the space velocity is above 100,000 $hr^{-1}$ To maximize light-off performance, this study suggests that 1) a light-off catalyst be designed double substrate type; 2) the substrate with high GSA and high PM loading at face be placed at the front monolith; and 3) the cell density of the rear monolith be lower to reduce the pressure drop.

• 구강회복응용과학지
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• 제23권1호
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• pp.69-78
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• 2007

This study was performed to compare the stress distribution pattern in the crestal cortical bone and cancellous bone using 3-dimensional finite element stress analysis when 2 different Young's modulus(high modulus, model 1; low modulus, model 2) of cancellous bone was assumed. For the analysis, a finite element model was designed to have two square-threaded implants fused together and located at first and second molar area. Stress distribution was observed when vertical load of 200N was applied at several points on the occlusal surfaces of the implants, including central fossa, points 1.5mm, 2mm, 3mm and 3.5mm buccally away from central fossa. The results were as follows; 1. In both model, the maximum Von-Mises stress in the crestal cortical bone was greater when the load was applied at the central point, points 1.5mm and 2mm buccally away from central fossa than other cases. 2. In the cortical bone around first and second molar, model 2 showed greater Von-Mises stress than model 1. It is concluded that when the occlusal contact is afforded, the distribution of stress varies depending on the density of cancellous bone and the location of loading. More favorable stress distribution is expected when the contact load is applied within the diameter of fixtures.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 1부
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• pp.318-322
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• 2010

NaZSM 5 was synthesized in an alkaline medium and impregnated with cerium oxide by wet method using cerium nitrate as the source for cerium. There TGA results shows decomposition of nitrate at $200^{\circ}C$. The ceria impregnated ZSM 5 materials were designated as NaZSM 5 (X) where X is the percent ceria impregnated (3, 5, 7, 11, 19%). They were characterized by XRD, SEM, EDAX, BET techniques. XRD analysis showed decrease in intensity of the patterns with the increase in the ceria loading but crystallization of ceria to larger size is evident for 11 and 19% loading. The surface area and pore volume decreased with increase in ceria loading. The maximum adsorption capacity of NaZSM 5 (5%) is 100.2 mg/g of sorbent. The ceria impregnated NaZSM 5's were found to be regenerable, selective and recyclable.

• 펄프종이기술
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• 제31권5호
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• pp.57-72
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• 1999

Traditional theories of the tensile failure of paper have assumed that uniform strain progresses throughout the sheet until an imperfection within the structure causes a catastrophic break. The resistance to tensile elongation is assumed to be elastic , at first, throughout the structure, followed by an overall plastic yield. However, linear image strain analysis (LISA) has demonstrated that the yield in tensile loading of paper is quite non-uniform throughout the structure, Traditional theories have failed to define the flaws that trigger catastrophic failure. It was assumed that a shive or perhaps a low basis weight area filled that role. Studies of the fracture mechanics of paper have typically utilized a well-defined flaw around which yield and failure could be examined . The flaw was a simple razor cut normal to the direction of tensile loading. Such testing is labeled mode I analysis. The included fla in the paper was always normal to the tensile loading direction, never at another orientation . However, shives or low basis weight zones are likely to be at random angular orientations in the sheet. The effects of angular flaws within the tensile test were examined. The strain energy density theory and experimental work demonstrate the change in crack propagation from mode I to mode IIas the initial flaw angle of crack propagation as a function of the initial flaw angle is predicted and experimentally demonstrated.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.592-598
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• 2005

The port, differently from general working places, is a closed area required for security, customs, and quarantine procedures. The loading and unloading is being done differently by ports, cargoes, and ships. To do loading and unloading, a lot of equipment and different types of labor are required, which flow is complicated and safe management is essential. As above mentioned the port is very unique and very deteriorated working place in its working environment. The purpose of this study is to propose ways to reduce and prevent from port accidents. As first step to do this, we have collected 923 accidents happened at Incheon Port during the period of 1994 to 2003. We have thoroughly analyzed characteristics, harmfulness, and risk of the loading/unloading they have done, as well as the accident frequency and relationship between the accidents. As second step to further analyze, We have employed DMAIC technology, an advanced process of 6 sigma presently in spotlight as the best program for management innovation. This analysis results in recognition of important accident characteristics, causes and effects analysis, critical causes of accident, and suggestions to decrease accidents.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.29-33
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• 1999

The present study examined annual runoff loading of nitrogen and phosphorus in the paddy field from 1 May, 1997 to 30 April, 1998. In the investigated area, the amount of rainfall was 1,095.6 mm and 414.6 mm during cropping season and non-cropping season. The annual rainfall was 1,510.2 mm. The total amount of runoff water was 1,043.2 mm and 281.0mm during cropping season and non-cropping season, and the added total amount of runoff water during two seasons was 1,324.2 mm. The runoff loading of nutrients caused by runoff water was measured as follows. The total-N was 149.23 and $8.67kg\;ha^{-1}$ (total amount=$157.90kg^{-1}ha^{-1}yr^{-1}$), the ammonia-N 102.98 and $4.44kg\;ha^{-1}$ ($107.42kg^{-1}ha^{-1}yr^{-1}$), the nitrate-N 28.45 and $1.23kg\;ha^{-1}$ ($29.68kg^{-1}ha^{-1}yr^{-1}$), the total-P 4.16 and $0.38kg\;ha^{-1}$ ($4.54kg^{-1}ha^{-1}yr^{-1}$) during cropping and non-cropping season respectively. When the loss ratio was calculated based on amounts of chemical fertilizer, about 68.6% of nitrogen and 16.7% of phosphorus was lost by runoff from applied fertilizer amount.

• 한국공간구조학회논문집
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• 제20권3호
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• pp.27-34
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• 2020

This paper examines the seismic performance and structural design of the ceiling bracket-type modular connection. The bracket-type system reduces the cross-sectional area loss of members and combines units using fitting steel plate, and it has been developed to be fit for medium-story and higher-story buildings. In particular, this study conducted the cyclic loading test for the performance of the C-type and L-type brackets, and compared the results. The test results were also compared with the commercial FEA program. In addition, the structural design process for the bracket-type modular connection was presented. The two connections, proposed as a result of the test results, were all found to secure the seismic performance level of the special moment steel frame. In the case of initial stiffness, the L-type bracket connection was found to be great, but in the case of the maximum moment or fully plastic moment, it was different depending on the loading direction.

• 한국해양공학회지
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• 제24권1호
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• pp.153-160
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• 2010

This paper deals with the topology optimized design of the riser support structures for floating production storage and offloading units (FPSOs) under global and local loading conditions. For a preliminary study and validation of the numerical approach, a simplified plate under static loading is first evaluated with the representative topology optimization methods, the Homogenization Design Method (HDM) and Density Method (DM) or Simple Isotropic Material with Penalization (SIMP). In the context of the corresponding riser support structures, the design problem is formulated such that structure shapes based on design domain variables are determined by minimizing the compliance subject to a mass target, considering the stress criterion. An initial design model is generated based on an actual FPSO riser support configuration. The topology optimization results present improved design performances under various loading conditions, while staying within the allowable limit of the offshore area.