• Journal of Powder Materials
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• v.13 no.1 s.54
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• pp.52-56
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• 2006

The aim of this work was to establish an optimal condition for determination of apparent density and flow rate for warm compacting powder. For this purpose it was evaluated uncertainty on them according to ISO Guide to the Expression of Uncertainty in Measurement. This evaluation example would be useful even in powder fluidity measurement at room temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.80-81
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• 2015

Thermal deformation behavior of high-strength concrete (HSC) exposed to fire is different from that of normal strength concrete (NSC). In case of ultra-high-strength concrete (UHSC), it is well known that thermal deformation behavior is greater than HSC. With increasing research of UHSC in buildings, it is necessary to understand the performance of UHSC at elevated temperatures considering loading condition. Therefore, evaluation on properties of thermal strain behavior properties of ultra high strength concrete by loading and high temperature was conducted.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.139-145
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• 2007

This paper presents the low cycle thermal fatigue of the engine exhaust manifold subject to thermomechanical cyclic loadings. The analysis includes the FE model of the exhaust system, temperature dependent material properties, and thermal loadings. The result shows that at an elevated temperature, large compressive plastic deformations are generated, and at a cold condition, tensile stresses are remained in several critical zones of the exhaust manifold. From the repetitions of thermal shock cycles, plastic strain ranges could be estimated by the stabilized stress-strain hysteresis loops. The method was applied to assess the low cycle thermal fatigue for the engine exhaust manifold. It shows a good agreement between numerical and experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.12 no.1
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• pp.1-10
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• 1999

In this paper, we have investigated the effects of the environmental factors on Low Molecular Weight (LMW) silicone fluid contents existing in high temperature vulcanized (HTV) silicone rubber sample, using dipping method and contact angle, current measurement. Artificial treatments such as immersion in water, elevated temperature, UV irradiation and dry band arcing under salt-fog condition are selected as the environmental factors. This results will be helpful to investigate the degradation with time and to expect a life time, because the LMW silicone content, which is important to recovery the hydrophobicity of silicone rubber surface, show different results by each environmental factors.

• Annals of Clinical Neurophysiology
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• v.21 no.1
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• pp.1-6
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• 2019

Anhidrosis refers to the condition in which the body does not respond appropriately to thermal stimuli by sweating. Sweating plays an important role in maintaining the body temperature, and its absence should not be overlooked since an elevated body temperature can cause various symptoms, even leading to death when uncontrolled. The various neurological disorders that can induce anhidrosis make a detailed neurological evaluation essential. The medication history of the patient should also be checked because anhidrosis can be caused by various drugs. The tests available for evaluating sweating include the quantitative sudomotor axon reflex sweat test, thermoregulatory sweat test, sympathetic skin response, and electrochemical skin conductance. Pathological findings can also be checked directly in a skin biopsy. This review discusses the differential diagnosis and evaluation of anhidrosis.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.157-165
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• 1997

The strength level of welded joint in room temperature and elevated temperature up to $600^{\circ}C$ was investigated in 250 and 300 grade 18% Ni maraging steel sheet welded with electron beam. The results obtained in this study are as follows; 1. Optimum welding heat input was 600J/cm in 1.0mm thickness and the room temperature tensile strength, joint efficiency of welded joint treated with optimum aging condition were found to be about 166kg/$mm^2$, 95% in 250 grade, 189kg/$mm^2$, 92% in 300 grade maraging steel sheet, respectively. 2. Tensile strength of welded joint in room temperature increased slightly by aging after repeated solution heat treatment, but the fracture mode showed a shear. 3. Joint efficiency at a temperature between $540^{\circ}C$and $600^{\circ}C$ found to be about 72% to 55%, but the joint efficiency exceeded about 90% below $300^{\circ}C$. 4. The fracture occurred in most weld metal, and the fracture surface showed a shallow dimple.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.1
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• pp.68-78
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• 1995

A study of expanding tobacco includes the steps of adjusting the moisture content of cut tobacco, without the use of exogenous impregnants by contacting the filler with a high velocity gaseous medium at elevated temperature such that heat is rapidly and substantially uniformly transferred from the medium to the filler for a total contact time sufficient to expand the tobacco leaves. Study is disclosed for drying and expanding cut tobacco by introducing the tobacco into an elongated tubular shaped conduit through which steam high temperature 150-35$0^{\circ}C$ and high velocity above the 18m1sec, super steam is recycled. moisture content of shreded tobacco leaves, immediately before treatment within the range of from 10% to 24% and, most preferably, within the range of from 18% to 21%. Expanding rate showed 70% in NC -82(B.3) and 42% in Burley -21(B.1) which is produced in 1993 under this condition. When expanding tobacco expanded tobacco did not change significally, but they were decreased at 27$0^{\circ}C$ very largely. The curtailment of cost price and physical and chemical properties of various items were improved in cigarettes. Key words : Expanding tobacco, Super steam tobacco expansion, Fast drying tobacco, High temperature treat tobacco, Puffing tobacco.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.2
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• pp.74-87
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• 2016

Potato phenology, growth, and yield are projected to be highly affected by global warming in the future. The objective of this study was to examine the responses of potato growth and yield to environmental elements like temperature, solar radiation, and daylength. Planting date experiments under open field condition were conducted using three cultivars differing in maturity group (Irish Cobbler and Superior as early; Atlantic as mid-late maturing) at eight different planting dates. In addition, elevated temperature experiment was conducted in four plastic houses controlled to target temperatures of ambient temperature (AT), $AT+1.5^{\circ}C$, $AT+3^{\circ}C$, and $AT+5^{\circ}C$ using cv. Superior. Tuber initiation onset was found to be hastened curve-linearly with increasing temperature, showing optimum temperature around $22-24^{\circ}C$, while delayed by longer photoperiod and lower solar radiation in Superior and Atlantic. In the planting date experiments where the average temperature is near optimal and solar radiation, rainfall, pest, and disease are not limiting factor for tuber yield, the most important determinant was growth duration, which is limited by the beginning of rainy season in summer and frost in the late fall. Yield tended to increase along with delayed tuber initiation. Within the optimum temperature range ($17^{\circ}-22^{\circ}C$), larger diurnal range of temperature increased the tuber yield. In an elevated temperature treatment of $AT+5.0^{\circ}C$, plants failed to form tubers as affected by high temperature, low irradiance, and long daylength. Tuber number at early growth stage was reduced by higher temperature, resulting in the decrease of assimilates allocated to tuber and the reduction of average tuber weight. Stem growth was enhanced by elevated temperature at the expense of tuber growth. Consequently, tuber yield decreased with elevated temperature above ambient and drop to almost nil at $AT+5.0^{\circ}C$.

• Journal of Powder Materials
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• v.11 no.4
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• pp.294-300
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• 2004

This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

• Design & Manufacturing
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• v.10 no.1
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• pp.12-18
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• 2016

Although magnesium alloy has received much attention to date for its lightweight and high specific strength, their applications are impeded by the low formability which is caused by the hexagonal crystal structure at room temperature. In general, equal-channel angular extrusion(ECAE) is recognized as one of the attractive severe plastic deformation techniques where the processed bulk metals generally achieve ultrafine-grained microstructure leading to improved physical characteristics and mechanical properties. ECAE process has several parameters such as angle of die, process temperature, process route and speed. During ECAE process of Mg alloy, these parameters has great influence on the extrudability and the mechanical properties of alloy. The aim of this study is to estimate the influences of process conditions on the formability of AZ31 and AZ31-CaO alloys. Mg alloys are processed through ECAE at elevated temperatures using three types of die with channel angle of $90^{\circ}$, $110^{\circ}$, $135^{\circ}$ using route $B_c$, respectively. This study discusses the feasibility of using ECAE to improve both formability and strength on magnesium alloys by comparative analyzing the mechanical properties and microstructural evolution in each condition.