This research has been conducted to design upright parts of hand-made vehicles with the purpose of reducing material and machining cost while ensuring structural safety. Aluminum knuckles were modelled with three parts in order to enhance design flexibility as well as to reduce CNC machining cost. A vehicle model was constructed in CAD program and simulated in ADAMS View in order to estimate joint forces developing during 20 degree step steering condition at 60km/h. The joint forces obtained in the vehicle dynamics simulation were used for the structural analysis in ANSYS and dimensions of knuckle parts were adjusted until the lowest safety factor reached 2.0. The weight of knuckle decreased by 50% compared to the previous version that was designed without the structural analysis. The overall manufacturing cost decreased by 33% due to the reduction in the material as well as the CNC machining effort.
An experiment was conducted to study effects of abomasal infusions of casein, glucose or starch on milk production and blood metabolites in dairy cows. Four lactating cows (559±41.9kg) fitted with 100 mm ruminal cannulas were used in a 4 × 4 Latin square experiment. The cows were given access ad libitum to grass silage and received 6.2 kg dry matter (DM) of a mixture of rapeseed meal (5.3kg/d DM) and barley grain (0.9kg/d DM) as a basal diet (CON), the basal diet plus intra-abomasal infusions of 270 g sodium caseinate (CAS), 300 g of glucose (GLU) or 243 g of starch (STA) starting at 09:00 h each day. Abomasal infusion of different nutrients did not affect (p>0.05) grass silage intake and rumen fermentation parameters (rumen pH, ammonia N and volatile fatty acids). As unexpected, milk yield and composition data did not differ between CON and the treated groups (p>0.05). Most of plasma amino acids were not significantly (p>0.05) affected by the abomasal infusions of CAS, GLU or STA except for histidine, tryptophan and glycine. Although histidine, known as the first limiting amino acid in dairy cows fed grass silage based diets, was significantly (p=0.003) increased by CAS, we failed to result in a clear increase in milk yield and protein yield. This discrepancy between plasma AA profiles and milk production could be presumably explained by relatively high concentration of total amino acids in the present study (2,039μmol/l).
Recently, national attention on the regulations for carbon dioxide emission has risen. Thus, diverse attempts are being actively carried out to reduce the resistance of ships and to develop a new propelling system that reduces the emission of carbon dioxide. This study presents to induce a way to utilize the generated wind power for the electrical energy source of a ship’s lighting, air conditioning and heating by installing a compact wind power facility on the experiment target; a small size high-speed vessel. The vessel targeted for application is a 30ft high-speed leisure boat made of aluminum alloy. The wind power facility installed on the hull and the batteries that will be charged by the electric energy generated by the wind power system were considered at the designing stage of the boat. A new presumption equation for air resistance of wind turbines and efficient measures for management are suggested based on a model test that verifies the basic performance of the wind-powered leisure boat.
The demand of energy is increasing around the world due to the high dependency of our society on energy. So the worldwide recognition of the limited supply of fuels has led to a large scale effort in search of alternative energy sources. Biodiesel has been considered as an alternative fuel to the petroleum diesel in compression ignition engines and is receiving more and more attention. Biodiesel can be obtained by the transesterification of methanol with triglycerides, with glycerin as by- product. This paper introduces the transesterification reaction of lard oil with methanol in the presence of hexane as solvent and potassium hydroxides as catalyst. Different from other researches, a new method to analyze the reaction process in this research was developed by starting with the by-product, crude glycerin. This new method was verified and the effects of various parameters such as solvent, molar ratio of methanol to oil (3:1-12:1), catalyst concentration (0.5-4 wt%) on the traneseterification process were investigated. Molar ratio of methanol to oil was optimized and identified to be 8:1, catalyst concentration of 2 wt% with hexane as solvent and at a temperature of 57℃ were found to be optimum for the reactions. Under this condition for 4 hours, the production yield can be 96.95%.
화학적 안정성이 양호하고, 제막조건이 온화한 재료인 poly(vinylidene fluoride) (PVDF)를 주재료로 사용하여 용매, 첨가제, 혼합고분자 및 제막조건의 변화에 따른 고강도 친수성 정밀여파(microfiltration, MF) 중공사 분리막의 실험에 의해 고찰하였다. 제조된 MF 중공사막의 막성능은 평균 공경 0.3 μm, 인장강도 42kgf/㎠, 순수 투과유량은 600 LMH을 얻었다. 제막과정에서 다양한 첨가제의 막성능을 검토한 결과는 순수투과유량과 제거율에 상당한 영향을 미치고 있음을 알 수 있었다. MF막의 친수성을 개선하기 위해 소수성 PVDF와 상호 용해성 이 좋은 친수성 poly(methyl methacrylate) (PMMA)를 혼합하여 투과성능과 제거율을 개선한 우수한 친수성 MF막을 제조할 수 있었다.
A survey project of TRAO with the fifteen beam array receiver system is presented. A multibeam array receiver system has been purchased from FCRAO, and is being installed on TRAO 14m telescope. The target region of the survey is from ι=120° ~137°, b=-1°~+1°, and velocity resolution would be 1 km/sec after smoothing from the original resolution of 0.64km s-1in the transition of J = 1-0 of 13CO The survey region is a part of the 12CO Outer Galaxy Survey(OGS), and would be an extension of the Bell Laboratories 13CO Galactic Plane Survey. By combining with the existing 12CO database of the Outer Galaxy Survey, we will derive physical properties of identified molecular clouds and will conduct and statistical analysis of the Outer Galalxy molecular clouds. Reduction process and analysis methods will be introduced.