• 한국농공학회지
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• 제17권1호
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• pp.3685-3701
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• 1975

This study was conducted to investigate the strength of soil cements for varied molding water content and cement content(3,6,9,12%) in four cementstabilized soils(KY: sand, MH: sad, SS: sandy loam, JJ: loam). The eoperimental results obtainedfrom unconfined compressive strength tests are asfollows: 1. The optimum moisture content increased in accordance with the increase of the cement while maximum dry density didn't change uniformly. 2. The moisture content for maximum strength was higher than the optimum moisture content in the higher cement content. Moisture-density curves showed a dull peak in the higher cement contents, on the other hand, a sharp peak in the lower cement contents. 3. In molding the specimen with the approximate optimum moisture content, the maximum strength showed at the wet side of the optimum moisture content. 4. SS and JJ maybe used as cement-stabilized base of road to require 300PSI of compressive strength cured seven days, but MH and KY may be not adequate. 5. In soil cement, the better the grain size distribution was, the stronger the compressive strength was itn general. 6. The relation between 28-day strengh and 7-day strength in the cementstabilized four soils may be expressed as follows: q28=1.55q7+1.5 in which q28:28-day strength. q7:7-day strength.

• 한국농공학회논문집
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• 제49권4호
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• pp.63-70
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• 2007

The soil samples used in this study were prepared with the residual granite soils passed through the #4 sieve and obtained from Pocheon in Gyeonggi-Ki do. Specifically, five types of samples were prepared. Sample A which is a natural state soil was classified as SM according to the uses. Samples of B, C, D, and E were prepared by mixing Sample A with bentonite and were classified as SC according to the uses. The plasticity indexes of samples B, C, D, and E were 15, 25, 30, and 40, respectively. The specimens, whose dimensions are 100mm by 127.5mm, were prepared by A method of ASTM D 698 with the Proctor mold. In experiments, the loading with the 1%/min was applied. Four different disk diameters, 13mm, 26mm, 38mm, and 52mm were used in the Improved Unconfined Penetration (IUP) tests. To compare the tensile strengths, the split tensile tests were also conducted on the same specimens used for the IUP tests. To find out the effects of moisture contents, plasticity Index of specimens on the tensile strength, six different water contents were used for making a specimen.

• 한국안전학회지
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• 제12권1호
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• pp.71-76
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• 1997

In this paper, it was described results of study on curing safety of molding meterial, about the variation of phenol resin contents, wood flour contents and moisture of wood flour, under the same condition. The experimental results are summarized as follows ; 1) When the curing temperature was high, the curing time was short in the case of 4～8wt% moisture of wood flour, but in the case of more than l2wt% moisture of wood flour, the curing time was long. 2) The curing time for curing temperature was more short when 6wt% moisture of wood flour than 4wt% moisture of wood flour. 3) The more wood flour content and moisture of wood flour content, the longer curing time and the more mineral filler content, the shorter curing time. 4) When the phenol resin content of main matrix increase, the curing time was short.

• 한국농공학회지
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• 제20권1호
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• pp.4575-4591
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• 1978

In order to investigate the effects of grain size distribution, cement content, and molding pressure on the strength and durability of soil-cement mixtures, a laboratory test of soil cement mixtures was performed at four levels of cement content, five levels of molding pressure, and four levels of normal curing periods. The results are summarized as follows: 1. Optimum moisture contents in loam soil and maximum dry density in sand soil increased with the increase of cement content, but in others, both optimum moisture contents and maximum dry density were changed ununiformly. 2. When the specimens were molded with molding pressure, 50kg/$\textrm{cm}^2$, strength of soil cement mixture with cement content, 2 and 4 per cent, was lower than the strength of soil cement mixture without cement content by more than 40 to 50 per cent. 3. The strength of soil-cement molded with molding pressure, 100kg/$\textrm{cm}^2$, was higher than the strength of soil-cement molded with M.D.D. obtained from standard compaction test more than 40 per cent in sand loam cement and 50 per cent in loamy cement. 4. There was highly significant positive correlation among molding pressure, cement content and unconfined compressive strentgh and so the following multiple regression equations were obtained. Loam: fc=1.9693C+0.197P-0.84 Sandy loam: fc=2.9065C+0.235P-0.77 5. When the specimens were molded with molding pressure, 20 to 100kg/$\textrm{cm}^2$, the regression equation between the 28-day and 7-day strenght was obtained as follows. Loam : q28=1.1050q7+7.59(r=0.9147) Sandy loam : q28=1.3905q7+3.17 (r=0.9801) 6. At the cement contents of above 50 per cent, the weight losses by freeeze-thaw test were negligible. At the cement content of below 8 per cent the weight losses were singnificantly high under low molding pressure and remarkably decreased with the increase of molding pressure up to 80kg/$\textrm{cm}^2$. 7. Resistance to damage from water and to absorption of water were not improved by molding pressure alone, but when the soil was mixtured with cement above 6 per cent, damage seldoms occurred and absorbed less than 5 per cent of water. 8. There was highly significant inverse-corelationship between the compressive strength of soil cement mixtures and their freeze-thaw loss as well as water absorption. By the regression equation methods, the relationships between them were expessed as followed fc=-7.3206Wa+115.6(r=0.9871) log fc=-0.0174L+1.59(r=0.7709) where fc=unconfined compressive stregth after 28-days curing. kg/$\textrm{cm}^2$ Wa=water absorption, % L : freeze-thaw loss rate, %

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.342-348
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• 2018

이 연구의 목적은 폐필름 포장재 재활용 성형재의 압축, 인장 및 휨 강도와 변형 특성을 생산 공장에 따라 측정하여 건설 2차제품의 적용 타당성을 평가하는 것이다. 재활용 성형재의 역학적 성능은 저밀도 폴리에틸렌 및 고밀도 폴리에틸렌의 일반적 값 수준으로 있지만 성능의 편차를 줄이고 품질의 안정화를 위해서는 1) 구성재료들의 혼합비율에 따른 재료 성능 평가; 2) 이물질 및 수분 함유량에 따른 재료성능 평가; 3) 다양한 제조 조건(제조공정, 가력 압력 및 폐필름 수거지역과 시기)에 대한 재료성능의 데이터베이스 관리 등의 현장 관리 체계마련이 요구되었다.

• Journal of Welding and Joining
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• 제18권4호
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• pp.64-69
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• 2000

Reliability of PBGA(Plastic Ball Grid Array) package is very weak compared with normal plastic packages. The reliability are the lower resistance to popcorn cracking, which is reduced by moisture absorption in PCB(Printed Circuit Board). This paper adapts plasma treatment process and analyzes their effect. The contents of C and Cl decrease after plasma treatment but O, Ca and N relatively increase. The Plasma treatment to improve the adhesion between EMC(Epoxy Molding Compound) and PCB(solder mask). The degree of improvement was over 100% Max., which is depend on the properties of EMC. Ar+H$_2$as plasma gas show good result. There is a little difference in RF power and treatment time.

• 한국전기전자재료학회논문지
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• 제13권10호
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• pp.805-811
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• 2000

Reliability of PBGA(plastic ball grid array) package is weak compared with normal plastic packages. The low reliability is caused by low resistance to the popcorn cracking, which is generated by moisture absorption in PCB(prited circuit board). In this paper, plasma treatment process was used and we analyzed its effects to interface adhesion. The contents of C and Cl decrease after plasma treatment but those of O, Ca, N relatively increase. The plasma treatment improves the adhesion between EMC(epoxy molding compound) and PCB(solder mask). The grade of improvement was over 100% Max, which depends on the properties of EMC. The RMS(root mean square) roughness value of the solder mask surface increases to plasma treatment. There is little difference of adhesion in RF power and treatment time.

• 펄프종이기술
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• 제41권4호
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• pp.43-51
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• 2009

Paper mill sludges are discharged around 870,000 M/T annually. Only 30% of the paper mill sludge have been recycled and the rest has been disposed by land fill, incineration, ocean abandonment and other ways. Because of overall prohibition of sludge disposal by London Dumping Convention in 2012, a urgent counter measure for paper mill sludge must be provided. In this paper, some basic experiments were carried out to develop a tray cell pot using paper mill sludge for increasing the recycling potential of the wasted sludge. To establish the manufacturing parameters, the tray cell pots were made with three types of materials including virgin pulp, old news paper and corrugated board mixed in a blend tank of a molding machine. The bending force and moisture content of the produced tray cell pots was measured to confirm the application capability. The tray cell pot could be manufactured under the condition of over 20% of virgin pulp, 40% of old news paper added. However, the corrugated board could not be used because of the glutinous substance included. The produced tray cell pot absorbed water very easily and the bending force decreased rapidly. The waterproof material must be used to applicate the produced tray cell pot in plant growing fields.

• 한국식품조리과학회지
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• 제24권5호
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• pp.652-664
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• 2008

In this study, a Hazard Analysis Critical Control Point (HACCP) plan was developed for the sanitary mass production of commercial Korean rice cake products (Gaepidduk, Injulmi, and Julpyon). The microbiological properties of manufacturing flow were evaluated in order to develop the HACCP Plan. The moisture contents of the rice cakes ranged between 36.2${\sim}$55.3%, whereas the water activity of all samples ranged between 0.954${\sim}$1.0. Microorganisms testing was conducted during various phases of the product flow of Korean rice cake preparation, and included assessments of food equipment, work environment, and cooking employees on a small scale. During the manufacture of Injulmi, Julpyon and Gaepidduk, CCPs were purchasing & storage, steaming and cooling, molding, and holding in the A and B manufactories. At the critical limit of CCPs, storage was conducted below at $5^{\circ}C$ in soybean powder, oil, and paste with redbeans. The steaming process was conducted above at $99^{\circ}C$ for 40 min. Cooling and holding processes were conducted for 2 hours below at $15^{\circ}C$. The molding process included sanitary education for foodhandlers and training for operators. Thus, certain prerequisite programs had to be implemented prior to the implementation of the HACCP system. High levels of bacterial contamination were detected in the aprons worn to work by some employees. Additionally, periodic sanitary education for foodhandlers and training for operators or managers was required. Cross contamination by materials was expected at the place where materials were processed or stored.

• 한국수산과학회지
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• 제49권6호
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• pp.766-771
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• 2016

The pacific oyster Crassostrea gigas has a desirable taste and flavor that differs from those of other fish and shellfish. In order to develop a high value-added product from individually quick-frozen oyster extract (IQFOE), we prepared an oyster granular flavor seasoning (OGS) from IQFOE and characterized its qualities. The OGS was prepared by granular molding and fluidized bed drying with inosine monophosphate (IMP, 0.1%), yeast extract powder (1.4%), tangle extract powder (0.6%), monosodium glutamate (MSG, 5.0%), microcrystalline cellulose (0.6%), lactose (27.5%), salt (33.0%), spray-dried IQFOE (22.5%) as a powdered materials, and IQFOE ($Brix\;25^{\circ}$, 7.0%), soy sauce (0.4%) and water (1.7%) as a liquid materials. The moisture, crude protein, pH and salinity of the OGS were 3.4%, 12.5%, 6.50 and 32.0%, respectively. Especially, the OGS revealed very higher amino-N content (1,856.0 mg/100 g) than that (1,291.2-1,610.2 mg/100 g) of other commercial flavor seasonings. In taste-active compounds, free amino acid contents was 1,359.0 mg/100 g, and major ones were glutamic acid, taurine, hydroxyproline, glycine, lysine, phosphoserine, proline in order. And OGS showed good organoleptic qualities for taste, odor and general preference compared with commercial flavor seasonings on a local market.