In this study, the structural integrity of the composite rocket motor case of a space launch vehicle was evaluated by conducting compression and bending tests. Two composite rocket motor case specimens with different stacking patterns were prepared for each test, and a dedicated jig was designed and manufactured. The test procedure was developed and applied separately for compression and bending tests. By performing these tests, the composite rocket motor case structural safety was assessed.

Numerous studies have attempted to predict the energy output of solar-powered vehicles based on different parameters such as road conditions, driver characteristics, and weather. However, since these studies were conducted on stationary vehicles, they are limited in their accuracy when applied to driving vehicles. This study aimed to improve the accuracy of electric power prediction for a solar-powered bus by applying a technique that improves energy efficiency without affecting driving performance. A comparative analysis of power generation and solar irradiance data was conducted for the bus driven on different roads to forecast its power generation, and a high-accuracy power generation prediction equation was derived. A comparison with actual test results revealed that a power generation forecast accuracy of at least 90% was achieved, validating the equation used for forecasting. With this power generation prediction process, it is possible to forecast the amount of energy generated in advance when a solar bus is operated in a specific area.

In this paper, the mechanical properties according to the rCF weight percent(10, 20, 30, 40, 50wt%) of the rCFRP specimen were evaluated and analyzed. First, to prepare rCFRP specimens, pellets were prepared according to the type of weight percent, and rCFRP tensile specimens according to ASTM D638 were prepared using an injection molding machine. Tensile tests were performed on each of 10 specimens according to weight percent conditions, and tensile strength and modulus of elasticity were calculated. For a detailed analysis of the correlation between the internal structure of the specimen and the mechanical properties, the weight percent to the constituent materials of the rCFRP specimen was calculated using mCT and used for the analysis of mechanical properties. For a more detailed analysis, a detailed analysis of the mechanical properties of rCFRP was performed through the fracture surface analysis of the specimen using FE-SEM.

There are differences of Cadmium (Cd) urinary concentration which is considered as indicator of renal tubular dysfunction in other countries, so we have reviewed domestic epidemiological data and suggested Korean health based guidance value (HBGV) for Cd to improve an efficiency of risk management. We decided to apply the WHO calculation model which considered the relationship between dietary intake and Cd concentration in urine sample. It is determined that Cd concentration 2.5 ug/g creatinine in urine as the prevalence of renal tubular dysfunction based on epidemiological data, because there is no renal tubular dysfunction and injury/lesion such as proteinuria at the concentration of 11.63 ug/g creatinine which is the highest Cd concentration in urine from the domestic epidemiological data. It is identified that the ratio between the Cd dietary consumption (8.3~10.4 ug/day) and Cd urinary concentration (0.38 ug/g creatinine) in Korean adult who predicting never been exposed to Cd are 21.8~27.3 and then it is applied to the corresponding model suggested by WHO. Also it is applied that 10% of bioavailability and 50% of excretion rate of absorbed to body (the ratio is 24) were assumed. The estimate of daily Cd consumption level which begins tubular dysfunction is 1 ug/kg bw/day, so we suggest the Korean provisional tolerable weekly intake (PTWI) as 7 ug/kg bw/week.

The purpose of this study was to introduce the toxicological study review to evaluate the safety of PDMS on the 69th JECFA meeting. Polydimethylsiloxane is a polymer and its ADI was established at 23rd JECFA meeting in 1979. The ADI was maintained although the specification was expanded at its 26th, 29 th, 37 th meetings. Recently, it was reported that PDMS with low molecular weight and viscosity has high absorption rate and different toxicity, so it was submitted at 69th meeting. Toxicological studies of PDMS were submitted from the sponsor and additional information is collected from a document searching. The toxicological studies were reviewed in accordance with the 'Guidelines for the preparation of toxicological working papers for the Joint FAO/WHO Expert Committee on Food Additives'. In the available acute, sub-chronic and chronic toxicity studies on PDMS, dose-related increases in incidence and severity of ocular lesions(corneal crystal, inflammation of the corneal epithelium etc.) were consistently observed after oral dosing. It seems to be a local irritant effect, but the mechanism by which the ocular lesions arose is unclear, although the lack of absorption of PDMS indicates that it is unlikely to be a direct systemic effect. Consequently, the relevance of the ocular lesions for food use of PDMS could not be determined. The ADI of PDMS was re-established from 0-1.5 mg/kg bw/day to 0-0.8 mg/kg bw/day by applying additional safety factor 2 based on its ocular toxicity. The result of 0-0.8 mg/kg bw/day is a temporary ADI until further data are provided to 2010.