• Geomechanics and Engineering
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• 제16권5호
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• pp.483-493
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• 2018

Experimental study of the deterioration of high-temperature rock subjected to rapid cooling is essential for thermal engineering applications. To evaluate the influence of thermal shock on heated granite with different temperatures, laboratory tests were conducted to record the changes in the physical properties of granite specimens and the dynamic mechanical characteristics of granite after rapid cooling were experimentally investigated by using a split Hopkinson pressure bar (SHPB). The results indicate that there are threshold temperatures ($500-600^{\circ}C$) for variations in density, porosity, and P-wave velocity of granite with increasing treatment temperature. The stress-strain curves of $500-1000^{\circ}C$ show the brittle-plastic transition of tested granite specimens. It was also found that in the temperature range of $200-400^{\circ}C$, the through-cracks induced by rapid cooling have a decisive influence on the failure pattern of rock specimens under dynamic load. Moreover, the increase of crack density due to higher treatment temperature will result in the dilution of thermal shock effect for the rocks at temperatures above $500^{\circ}C$. Eventually, a fitting formula was established to relate the dynamic peak strength of pretreated granite to the crack density, which is the exponential function.

• Asian-Australasian Journal of Animal Sciences
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• 제29권6호
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• pp.855-864
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• 2016

The objective of this study was to compare the physicochemical and nutritional properties of breast and thigh meat from commercial Chinese crossbred chickens (817 Crossbred chicken, 817C), imported commercial broilers (Arbor Acres broiler, AAB), and commercial spent hens (Hyline Brown, HLB). The crossbred chickens, commercial broilers and spent hens were slaughtered at their typical market ages of 45 d, 40 d, and 560 d, respectively. The results revealed that several different characteristic features for the three breeds. The meat of the 817C was darker than that of the other two genotypes. The 817C were also characterized by higher protein, lower intramuscular fat, and better texture attributes (cooking loss, pressing loss and Warner-Bratzler shear force [WBSF]) compared with AAB and HLB. The meat of the spent hens (i.e. HLB) was higher in WBSF and total collagen content than meat of the crossbred chickens and imported broilers. Furthermore, correlation analysis and principal component analysis revealed that there was a clear relationship among physicochemical properties of chicken meats. With regard to nutritional properties, it was found that 817C and HLB exhibited higher contents of essential amino acids and essential/non-essential amino acid ratios. In addition, 817C were noted to have highest content of microelements whereas AAB have highest content of potassium. Besides, 817C birds had particularly higher proportions of desirable fatty acids, essential fatty acids, polyunsaturated/saturated and (18:0+18:1)/16:0 ratios. The present study also revealed that there were significant differences on breast meat and thigh meat for the physicochemical and nutritional properties, regardless of chicken breeds. In conclusion, meat of crossbred chickens has some unique features and exhibited more advantages over commercial broilers and spent hens. Therefore, the current investigation would provide valuable information for the chicken meat product processing, and influence the consumption of different chicken meat.

• 한국안전학회지
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• 제19권3호
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• pp.40-44
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• 2004

To the removal of hardness materials, we've test the absorptive capacity of main material $Mg^{2+},\;Ca^{2+}$ on the using the activated carbon powder saturated in 0.1M Nitrilotriacetic acid by experimental methods. The absorptive properties of $Ca^{2+}\;and\;Mg^{2+}$ were measured with absorbent quantity and contact time., and investigated the physical properties of overall rate constant and adsorption constant adsorption isotherm, and Langmuir and Freundlich constant. In case of k' adsorption rate constants of $Ca^{2+},\;Mg^{2+}$, was 0.00299, 0.00529 by Bhattahary and Venkobachar equation. $k_{aa}$ was 0.00373, 0.00640 according with adsorption rate constants of Lagergren.

• 자동차안전학회지
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• 제5권1호
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• pp.25-30
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• 2013

The main purpose of this research is to predict dynamic behavior of door locking system for side impact safety and the design process to avoid door opening is introduced. The equations of motion that represent the system are obtained from the energy equation. From them, the motion of door handle is predicted by using Runge-Kutta $4^{th}$ order method and the simulation result is compared with the real crash data. Also, the design guide to define the properties of door locking system from the standpoint of avoiding door opening phenomenon is introduced.

• 한국안전학회지
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• 제18권3호
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• pp.94-100
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• 2003

Gel-like compounds containing flammable solvents were prepared to use fur cleaning agents in field of innovative industries and general purposes. And experiments were conducted to improve the defects of liquified flammable solvents from the view point of safety and health hazards. Flammable solvents used in this study were several single component flammable solvents(turpentine oil, N-methyl-2-pyrrolidone(NMP), d-limonene) and multi component flammable solvent(gasoline and ethanol). For gelation of flammable solvents, commercially Known as Aerosil(equation omitted) 200 fumed silica and triethanolamine(TEA) were used as gelation agent dispersant. The analyses on properties of gel-like compounds was studied by gelation and viscosity test pH test, volatility test and differential scanning calorimetry(DSC) measurement. The experimental results indicate that gel-like compounds containing flammable solvents have pH stability, high viscosity, volatile organic compounds(VOC) control by the decrease of volatility and odor component generation, fluidity control etc. From the experimental values, it can be predicted that the safety in the working place is improved by manufacturing flammable solvents into gel-like compounds.

• 한국위험물학회지
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• 제6권2호
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• pp.23-29
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• 2018

The fire and explosion properties necessary for waste, safe storage, transport, process design and operation of handling flammable substances are lower explosion limits(LEL), upper explosion limits(UEL), flash point, AIT( minimum autoignition temperature or spontaneous ignition temperature), fire point etc., An accurate knowledge of the combustion properties is important in developing appropriate prevention and control measures fire and explosion protection in chemical plants. In order to know the accuracy of data in MSDSs(material safety data sheets), the flash point of phenol was measured by Setaflash, Pensky-Martens, Tag, and Cleveland testers. And the AIT of phenol was measured by ASTM 659E apparatus. The explosion limits of phenol was investigated in the reference data. The flash point of phenol by using Setaflash and Pensky-Martens closed-cup testers were experimented at $75^{\circ}C$ and $81^{\circ}C$, respectively. The flash points of phenol by Tag and Cleveland open cup testers were experimented at $82^{\circ}C$ and $89^{\circ}C$, respectively. The AIT of phenol was experimented at $589^{\circ}C$. The LEL and UEL calculated by using Setaflash lower and upper flash point value were calculated as 1.36vol% and 8.67vol%, respectively. By using the relationship between the spontaneous ignition temperature and the ignition delay time proposed, it is possible to predict the ignition delay time at different temperatures in the handling process of phenol.

• Computers and Concrete
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• 제30권4호
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• pp.257-267
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• 2022

Two different types of rubber aggregates (40 mesh rubber powder and 1-4 mm rubber particles respectively) were devised to substitute fine aggregates at 10%, 15%, 20% and 30% by volume in self-compacting concrete to investigate their basic mechanical properties. The results show that with the increase of rubber content, the reduction of compressive strength, splitting tensile strength and static modulus of elasticity gradually increase, and energy dissipation performance gradually increase. The rubber addition significantly reduces brittleness and decelerates damaged process. Whilst, the effect of rubber particles is greater when they are finer. Considering the mechanical properties, the optimal rubber content is 10%. It is recommended that the rubber volume content in rubberized concrete (RC) should not be higher than 20%. In addition, a constitutive model under uniaxial compression was proposed basing on the strain equivalent principle of Lemaitre and the damage theory, which was in good agreement with the test curves.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2000년도 춘계학술대회
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• pp.443-448
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• 2000

• 한국기계가공학회지
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• 제17권3호
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• pp.39-44
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• 2018

The automotive headrest is intended to provide comfort, safety, convenience and durability to a vehicle's passengers and driver. In this study, impact and fatigue analyses were carried out for three headrest shape models-A, B and C. These models have the same material properties and the same force was applied to them. Impact and fatigue analyses demonstrated that all of the models obtained almost the exact same result values. This study found that all models had similar equivalent stress, deformation, fatigue life and main damage parts due to the fact that the shared same material properties. Better safety and fatigue life can be anticipated by changing the material of the headrest in order to secure more stable safety. An automotive headrest optimized for safety and durability is thought to have been developed through the impact and fatigue analyses of this study.

• 한국안전학회지
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• 제31권4호
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• pp.42-47
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• 2016

The combustible properties(flash point, explosion limit and autoignition temperature) are the important safety items which are considered in the typical MSDS(material safety data sheet). In this study, for the safe handling of n-butyl methacrylate(n-BMA) being used in various ways in the chemical industry, the flash point and the autoignition temperature(AIT) of n-butyl methacrylate was experimented. And, the lower explosion limit of n-butyl methacrylate was calculated by using the lower flash point obtained in the experiment. The flash points of n-butyl methacrylate by using the Setaflash and Pensky-Martens closed-cup testers measured $44^{\circ}C$ and $51^{\circ}C$, respectively. The flash points of n-butyl methacrylate by using the Tag and Cleveland open cup testers are measured $53^{\circ}C$. The AIT of n-butyl methacrylate by ASTM 659E tester was measured as $295^{\circ}C$. The lower explosion limit by the measured flash point $44^{\circ}C$ was calculated as 0.85 vol.%. It was possible to predict lower explosion limit by using the experimental flash point or flash point in the literature.