• 한국토양비료학회지
• /
• 제41권4호
• /
• pp.239-246
• /
• 2008

제올라이트는 높은 양이온교환능력(CEC)으로 인해 토양개량제의 사용이 고려되어 왔으나, 이에 관한 연구들의 대부분이 제올라이트를 합성하거나 천연제올라이트의 CEC를 증가시키는데 국한되어왔다. 실제로 제올라이트를 토양개량제로 사용하기 위해서는 유실되는 것을 방지하기 위한 과립화 (granulation or pelletizing)가 요구된다. 본 연구는 제올라이트를 토양개량제로 활용하기 위해 이를 포함하는 소성점토의 과립 (calcined clay granule)을 제조하고, 제올라이트의 특성을 최대로 활용할 수 있는 과립의 제조조건을 찾으려 하였다. 천연제올라이트, 고령토, 규석을 재료로 하여, pan granulator와 high shear mixer granulator의 두가지 과립기를 사용하여 과립을 제조하였다. 재료의 혼합비와 과립기의 회전속도 등을 조절하여 과립을 제조하였으며, 이를 $400\sim700^{\circ}C$범위에서 $100^{\circ}C$단위로 소성한 후 파쇄강도 (crushing strength), 기공분포 (pore distribution), CEC를 측정하였다. 토양개량제로 사용할 과립은 취급시에 요구되는 기본적인 강도뿐만 아니라 토양과 혼합된 후 답압(踏壓)에 견디기 위한 강도 또한 요구된다. 본 연구에서는 과립의 답압에 관한 저항성 평가방법을 마련하고, 마른 상태와 젖은 상태에서 과립의 저항성을 측정하였다. 과립기의 회전속도와 가열온도에 비례하여 답압에 대한 저항성은 증가하나 CEC는 감소하였다. Pan granulator는 $700^{\circ}C$이하의 가열에서 적절한 강도를 갖는 과립을 제조할 수 없었으나, high shear mixer granulator는 $500^{\circ}C$이상의 가열에 의해 답압에 저항성을 갖는 과립을 제조할 수 있었다.

• 대한가정학회지
• /
• 제46권1호
• /
• pp.47-61
• /
• 2008

The purpose of this study is to provide information about domestic living of Korean immigrants in Australia and Canada who have the same cultural background for comparative study. For this, usage of domestic space and living style in housing of 52 Korean households in Melbourne of Australia and 32 Korean households in the region of Waterloo of Canada were analyzed. Ethnographic research with questionnaire were used. Results of the research were as follows. 1. Korean immigrants in each countries were living in houses which was built by company of Australia and Canada. 44.2% of Korean immigrants in Australia were using L+D K and 53.1% of Korean immigrants in Canada were using L D K. 2. Laundry was indispensable for Korean immigrants in both countries and they all wanted to use the laundry as a utility room which could dry, ironing and so on. 3. Drain hole on the floor of the bathroom was not indispensable for most Korean immigrants in both countries for hygienic reason. 4. Korean immigrants in both countries were ironing in master bedroom and they all wanted to separate it from there through renovation and extension and so on. 5. Korean immigrants in Canada were more active to use the formal lounge which has been planned as a traditional element of western house. 6. The seating style of Korean immigrants in both countries belong to chair-seating style mostly. But it was clear that they were making Kimchi with floor seating style in both countries. 7. A level of satisfaction about using carpet was not high for Korean immigrants in both countries cause of uneasiness to clean and it was considered to relate to the floor seating style of them. 8. Almost Korean immigrants were took off the shoes inside of the house and they had shoes cabinet beside the entrance or basement usually. 9. The most popular heating system was ducted heating in both countries. The level of satisfaction about this was different for Korean immigrants in Australia and Canada but most desirable heating system was Ondol for them in both countries commonly.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 C
• /
• pp.1778-1780
• /
• 2004

Microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the reliability of operation in the beginning of plasma formation and non-inductive current drive for long time steady state operation with maintaining MHD stability, respectively. LHCD demands 5 GHz of frequency and consists of c-band waveguide, 4-port circuitor, dry dummy load, dual directional coupler, E-bend, arc detector. Our system is a lineup type pulse modulator that has 45 kV of output pulse voltage, 90 A of pulse current, 4 us of pulse width. 1:4 step-up pulse transformer, 7 stages of PFN and thyratron tube (E2V, CX1191D) are used in this modulator. The purpose of this paper is to show the modulator design and experimental result.

• 한국대기환경학회지
• /
• 제26권3호
• /
• pp.286-297
• /
• 2010

This study deals with the effect of pretreatment on the $CO_2$ adsorption capacity of zeolitic adsorbents including a commercial A-type zeolite and cation exchanged adsorbents. The pre-heating could change the intrinsic properties such as specific surface area and adsorption capacity of the adsorbent. As a result of the experiment, the moisture previously filled inside might affect the potential adsorption capacity of the adsorbent, and could be disappeared throughout the heat treatment. An optimum pretreatment temperature for the test adsorbent was found to be $400^{\circ}C$, at which temperature enabled more than 90% refreshment. Precise examination through the TPD test showed that the TSA (Temperature Swing Adsorption) process would be desirable in dry adsorption of $CO_2$.

• 한국산업융합학회 논문집
• /
• 제5권1호
• /
• pp.81-89
• /
• 2002

The objective of this paper is to clarify the combined effect of heat conduction, air temperature and thermal radiation on the person seated on the floor under operation of floor heating system. Experiments were conducted for summer seasons under 8 kinds of condition: combinations of air temperature $20^{\circ}C$, $22.5^{\circ}C$ and floor temperature $20^{\circ}C$, $22.5^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$ and $40^{\circ}C$ under still air. Japanese and Koreans were adopted as subjects. To evaluate the effect of conduction operative temperature modified by heat conduction was derived from the human heat balance equation. New weighting coefficients were estimated from the modified operative temperature and modified mean skin temperature. As for thermal sensation the modified operative temperature more significantly correlated to that sensation each heat transfer processes. As the floor temperature is higher, the human conduction heat gain from floor increase and the dry heat from the human body decrease.

• 한국식품조리과학회지
• /
• 제27권6호
• /
• pp.745-754
• /
• 2011

To improve the textural properties of gluten free rice flour based products, the physicochemical and pasting properties of extruded non-waxy rice flours using extruder were investigated. The high yielding Tongil type rice variety, Hanarum was used. Hanarum rice flour was prepared by dry milling from soaked and dried rice grain. The operation conditions of twin screw extruder were 250 rpm of screw speed, $160^{\circ}C$ of barrel temperature, and 24, 27, and 30% of moisture content. Hanarum extruded rice flour (HERF) were lower in crude lipid and ash contents, but higher in crude protein than Hanarum rice flour (HRF). The color values of HERF showed significantly different (p<0.05) with different moisture contents. Water binding capacities, apparent amylose contents, and damaged starch of HERF were higher than those of HRF. Moisture contents affected water binding capacities of HERF. Solubility increased with increasing heating temperature and solubilities of HERF differed significantly (p<0.05). X-ray crystallinity was changed after extrusion cooking and that of HERF showed sharp peaks at $2{\theta}=18-20^{\circ}$. The pasting viscosities of HERF kept lower values (~ 10 RVU) constantly.

• Asian-Australasian Journal of Animal Sciences
• /
• 제5권4호
• /
• pp.593-600
• /
• 1992

Animal welfare is often neglected by livestock productionists when considering the utilization of animal wastes for livestock feeds. The present review has been carried out to examine the nutritive value of poultry wastes for ruminants, the health risks involved with feeding it, the treatment and feeding methods and the production responses of animals fed on it. It was found that mineral, crude protein, crude fibre and metabolisable energy concentrations are influenced by the system of poultry production, the storage of the waste and the treatment method. Heating at $60^{\circ}C$ kills all pathogens apart from Clostidium botulinum whereas proper ensiling kills all. Apart from the kidney fat and the liver, animal tissues have not shown residues of drugs or heavy metals from poultry wastes. Palatability is affected when the moisture is more than 200 g/kg. Production responses are satisfactory when poultry wastes replace portions of concentrates. It was concluded that poultry litter generally has higher metabolisable energy contents than poultry manure, but research is needed to classify poultry litters on their energy values. The adverse effects of toxic minerals and drug residues are negligible in balanced poultry waste feeding systems.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제15권1호
• /
• pp.34-45
• /
• 2007

In order to reduce the compression power and to use the overall energy contained in LNG effectively, a combined cycle is devised and simulated. The combined cycle is composed of two cycles; one is an open cycle of liquid/solid carbon dioxide production cycle utilizing LNG cold energy in $CO_2$ condenser and the other is a closed cycle gas turbine which supplies power to the $CO_2$ cycle, utilizes LNG cold energy for lowering the compressor inlet temperature, and uses the heating value of LNG at the burner. The power consumed for the $CO_2$ cycle is investigated in terms of a solid $CO_2$ production ratio. The present study shows that much reduction in both $CO_2$ compression power (only 35% of the power used in conventional dry ice production cycle) and $CO_2$ condenser pressure could be achieved by utilizing LNG cold energy and that high cycle efficiency (55.3% at maximum power condition) in the gas turbine could be accomplished with the adoption of compressor inlet cooling and regenerator. Exergy analysis shows that irreversibility in the combined cycle increases linearly as a solid $CO_2$ production ratio increases and most of the irreversibility occurs in the condenser and the heat exchanger for compressor inlet cooling. Hence, incoming LNG cold energy to the above components should be used more effectively.

• 대한가정학회지
• /
• 제41권2호
• /
• pp.107-121
• /
• 2003

This study was discussed the dyeing of wool and nylon fabrics with Chinese Scholar Tree extract. The extracts of Chinese Scholar Tree was prepared in the condition of heating at $95{\pm}5C$, for 1 hour and cooling to 40C. And then the extracts of color matter treate with vacuum concentration at $60{\pm}2^{\circ}C$, 30mmHg and dried with spray dryer. The dyeing of wool and nylon fabric in this experiment was also employed the mordant dyeing method such as pre-mordant, post-mordant and simultaneous mordant method. The mordanting agents used in this study were as followings ; aluminium potassium sulfate, copper(II) acetate monohydrate, chromium potassium sulfate$.$$7H_2O$, Tin(II) chloride dihydrate, iron(II)sulfate $7H_2O$. For an evaluation of the dyeing property of the mordanting agents, the pre-mordant method, the repeat dyeing and the fastness of the light, dry cleaning, washing and rubbing measured respectively. From the results of the dye absorption, the optimum dyeing condition of the wool and nylon fabrics with Chinese Scholar Tree extract is at 80C dyeing temperature for 60 minutes. The optimum concentration of mordanting agent is Al, Cr, Sn 1%, Fe, Cu 2% solution. In general, the fastness property of the dyed wool and nylon fabrics had a comparatively high grade.

• Tribology and Lubricants
• /
• 제22권3호
• /
• pp.137-143
• /
• 2006

The sliding contact interface of machine components such as bearings, gears frequently operates in lubrication at the inception of sliding failure under high loads, speed and slip. The surface temperature at the interface of bodies in a sliding contact is one of the most important factors influencing the behavior of machine components. Most surface failure in sliding contact region result from frictional heat generation. However, it is difficult to measure temperature rise experimentally. So the calculation of the surface temperature at a sliding contact interface has long been an interesting and important subject for tribologist. The surface temperature rise is related in contact pressure, sliding speed, material properties and lubrication thickness. Though roughness, load, ect all of the condition, are same, film thickness varies with velocity. In this study, surface temperature rise due to frictional heating in lubrication is calculated with various velocities. Surface film shearing and dry solid asperity contact are used to simulate the change of frictional heat in lubricated contact