• Journal of the Korean Wood Science and Technology
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• 제21권4호
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• pp.64-72
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• 1993

Mechanical properties of 15 mm thick, three-layer particleboard were studied by varying resin content, specific gravity, mat moisture content, pressing time and pressing temperature. Based on the results of the study, Multiple regression models were developed to estimate the mechanical properties of three-layer particleboard. The results of this study showed the mechanical properties of particleboard were highly related with resin content. specific gravity and mat moisture content in decending order. The mechanical properties were able to estimated as the linear function of resin content and specific gravity. However, the effects of change in mat moisture content on the mechanical properties showed a non-linear pattern. The mechanical properties curves over mat moisture content reached peaks at 15 %, and then decreased at 18 % and 21 % of mat moisture contents. On the other hand, the effects of pressing time and pressing temperature on the mechanical properties of particleboard were not significant.

• Journal of the Korean Wood Science and Technology
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• 제10권3호
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• pp.189-189
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• 1982

This study was carried out to determine the possibility of making fiberboard through the dry forming process, utilizing the tannin-like material of the Asplund pulp from the silk worm oak as a binder. The fiberboard was made through paraformaldehyde treatment, spray of NaOH solution and adjustment of mat moisture content, by hot-pressing at $220^{\circ}C$, and 50-6-50kg/$cm^2$ pressure with 6-min. (0.6-1.8-3.6) three-stage pressing cycle. The results are summarized as follows: 1. The modulus of rupture value of fiberboard treated with NaOH solution was greater than that of untreated. The value was increased in proportion to the paraformaldehyde content from I to 5%, but there was no increasing between 5 and 7% paraformaldehyde content. The value became higher along with the increase of mat moisture content from 15% to 25%. 2. The water adsorption of fiberboard treated with NaOH solution was lower than that of untreated. The value was de"creased in proportion to the paraformaldehyde content from 1 to 5%, but there was no decreasing between 5 and 7% paraformaldehyde content.. 3. A good quality fiberboard (modulus of rupture value of about 250kg/$cm^2$) was made through 5% paraformaidehyde treatment and 3% treatment of 10% NaOH solution, when the mat moisture content was 25%. was 25%.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.48-57
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• 1979

In order to obtain a standard reference for designing an adequate power rice transplanter, the cutting forces depending upon variety of seedling, sowing density, seedling age and soil moisture content of mat-type seedling were measured by the rice transplanter installed with force measuring device of dynamic strain gage system in the laboratory. The result of this study are summarized as follows : 1. Cutting velocity and acceleration transplanting hoe obtained from jinematic analysis of planting mechanism was 1.32m/sec and 81.5m/$sec^2$ when planting crank-shaft rpm was 160. 2. Little difference between cutting forces on 30-days old seelings of japonica and Indica type was observed, as the cutting forces determined were 2.0kg per hill for Japonica type and 2.1kg per hill for Indica type. 3. Cutting forces determined on 40-days old seedlings were 2.5kg, 2.3kg, 3.1kg and 2.9kg per hill for Milyang No.15, Tongil, Akibare and Milyang No.23 compared to the other varieties. 4. The cutting force was not greatly affected by the sowing densities , only five percent of differences were observed epending upon the sowing densities. 5. Cutting forces were 2.7kg and 2.0kg per hill on 40-days old seedlings and 30-days old seedlings respectively. About 38 percent of more forces was required in cutting 40-days old seedling than in cutting 30-days old seedlings. 6. More cutting forces were required as soil moisture content of mat-type seedling was decreased. 7. Root length after cutting by the planting hoe and their relationships with soil moisture content on 30-days old seedlings, are as follows ; $y=4.147-11.384x+ 28.854x^2$ where , $y$=root length after cutting. (cm) , $x$=soil ture content of mat type seedlings.(%, d.b.) 8. Cutting forces were varied with the width of cuttings ; those on 40-days old mat type seedlings were 2.7kg and 2.2kg per hill when cutting with 14 mm and 10mm of width respectively, about 32 percent of more forces was required when cuting with 14mm of width compared to 10mm of width.

• Journal of the Korean Wood Science and Technology
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• 제23권4호
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• pp.85-90
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• 1995

목질보드 제조에 있어 매트의 최종함수율은 에너지가 필요한 목질 엘리먼트의 초기 건조공정이나 열압싸이클공정, 목질보드의 균질정합성, 목질재료의 물리 기계적 성질 및 치수안정에 지대한 영향을 주기 때문에 대단히 중요하다. 지금까지 PB에 대한 최종매트의 함수율에 대한 연구는 많이 보고되어 있으나 요소수지로 제조되는 MDF에 대한 연구보고는 없으며 미국과 한국을 위시한 각국이 MDF의 최종함수율을 PB에 준하여 8~11%로 조정하여 MDF를 제조하고 있다. 따라서 본 연구는 미국산 침엽수 혼합수종으로부터 제조된 가압 해섬섬유와 요소수지로 제조된 MDF의 물리 기계적 성질에 관련된 적정 최종매트 함수율을 규명하고자 실시하여 다음과 같은 결론을 얻었다. 1. 혼합 침엽수 원료로부터 제조된 요소수지제조 MDF의 적정 최종 매트 함수율은 13% 부근으로서 현재 MDF공장에서 적용되고 있는 8~11%보다 높았다. 2 평판이 시작되는 최종매트 함수율은 15.4%였다.

• Journal of the Korean Wood Science and Technology
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• 제25권2호
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• pp.33-44
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• 1997

This study was executed to examine the effects of polypropylene fiber length and process variables of the composites made from wood fiber and nonwood fiber mixed formulations. As a nonwood fiber the polypropylene with 3 denier thickness of tow condition was selected and cut into each length of 0.5, 1.0, 1.5, 2.0 and 2.5cm to mix with wood fiber. And also western hemlock wood fiber for medium density fiberboard was prepared. First, to decide an adequate polypropylene mixing fiber length, the composites of 1.0g/$cm^3$ density were made from 10% polypropylene fiber by each of five lengths and 90% western hemlock fiber mixed formulations. Thereafter as the experiments of process variable, the composites applied with adequate polypropylene fiber length(1.5cm) were made from 4 density levels (0.6, 0.8, 1.0, 1.2g/$cm^3$). 3 mixed formulations of wood fiber to polypropylene fiber(95 : 5, 90 : 10, 85 : 15), and 3 mat moisture contents(5, 10, 20%). According to the results and discussions it was concluded as follows ; The physical and mechanical properties were shown improved tendency. as polypropylene fiber length was increased in the range from 0.5 to 1.5cm, but shown decreasing tendency from 2.0 to 2.5 cm. Accordingly, it was shown that polypropylene fiber length is limited to 1.5cm or less length in mixing wood fiber and polypropylene fiber by turbulent air mixing process. As the densities of wood fiber-polypropylene fiber composites were increased, the physical and mechanical properties were clearly improved. Also they were shown significantly increasement statistically between densities respectively. In the mixed formulations, physical and mechanical properties were shown only slightly improvement, as they changed from 95 : 5 to 85 : 15 in wood fiber to polypropylene fiber. Despite of increasement of mat moisture content, mechanical properties were not improved significantly but physical properties were improved somewhat in wood fiber-polypropylene fiber composites.

• Journal of the Korean Wood Science and Technology
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• 제33권3호통권131호
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• pp.22-29
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• 2005

이 연구는 숯파티클 크기에 따른 최종 매트 함수율에 관한 백탄보드의 적정제조조건을 규명할 뿐 아니라 백탄보드가 새집증후군에 대한 친환경적 재료로서 백탄의 유익한 성질을 그대로 유지하도록 하기 위하여 수행되었다. 우수한 기능성을 갖는 백탄보드는 최종매트함수율이 20~25%와 36~60%의 2개 그룹에서 생산되었다. 최종매트함수율이 높은 후자는 훨씬 우수한 결과를 나타내었고 비포름알데히드계 접착제[MDI(M), poly vinyl acetate emulsion(P)]와 30-10-$3kgf/cm^2$ (1분-1.5분-6분)의 3단계 열압공정으로 제조된 #40~60형-P15%, M5%, FMC60%와 혼합형-P15%, 5%, FMC36%의 2 종류였다. 숯파티클이 큰 쪽은 최종매트함수율이 적게 필요하였고 #6이상-M15%, FMC25%와 혼합형-M25%, FMC20%의 2 종류가 전자에 속하였다. 백탄보드는 치수안정성, 가스흡착 그리고 원적외선방사율에서 우수한 결과를 나타내었다.

• 한국가구학회지
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• 제21권3호
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• pp.237-247
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• 2010

This research was carried out to examine the properties of black charcoal board, in order to find the proper manufacturing condition for the black charcoal-board made of the charcoal. The charcoal in this study was distillated from domestic wood waste, and it were also the purpose of this study to see if the black charcoal-board has the advantageous properties of charcoal as a well-being building material against the sick house problem. Domestic wood waste was consisted of MDF 40%, PB 30%, plywood 15% and wood 15%, respectively. Black charcoal board was produced by hot pressing with following conditions; temperature $170^{\circ}C$, three stage pressing cycle of $40-10-40\;kgf/cm^2$(1min.-2.5min.-5min.) and non formaldehyde adhesives [P15%+M5%:MDI(M), poly vinyl acetate emulsion(P). Fine mixed particle size [#6-12(16.9%), #12-18(16.7%), #12-40(47.2%), #40-60(9.5%), #60-100(5.9%), less than #100(3.8%)] gave better results than larger particle size [over #6(33.8%), #12-18(17.7%), #12-40(37.7%), #40-60(6.4%), #60-100(2.6%), less than #100(1.8%)]. Final moisture content of the mat was best at 36%. Black charcoal-board showed less MOR and IB(internal bond), more WA(water absorption) than that of white charcoal-board. Black charcoal board showed not only the same gas adsorption and dimensional stability as white charcoal board but also good cutting, nailing and drilling for indoor environment systems.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.734-738
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• 2002

We present spectral characteristics of tidal flat sediments and algal mat that were tested in the Gomso and Saemangum tidal flats, Korea. The objective of this study is to investigate the spectral reflectance and the radar scattering modeling in the tidal flats. Ground truth data obtained in the tidal flats include grain size, soil moisture content and its variation with time, surface roughness, chlorophyll, ground leveling, and field spectral reflectance measurement. The concept of an effective exposed area (EEA) is introduced to accommodate the effect of remnant surface water, and it seriously affects the reflection of short wavelength infrared and microwave. The nin size of 0.0625 mm has been normally used as a critical size of mud and sand discrimination. But we propose here that 0.25 mm is more practical grain size criterion to discriminate by remote sensing. Algal mat is the primary product in tidal flats, and it is found to be very important to understand spectral characteristics for tidal flat remote sensing. We have also conducted radar scattering modeling, and showed L-band HV-polarization would be the most effective combination.

• Journal of the Korean Wood Science and Technology
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• 제26권1호
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• pp.76-86
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• 1998

Effects of processing variables and MAPP (maleic anhydride polypropylene) coupling agent on the properties of composite were discussed for turbulent-air-mixed woodfiber-polypropylenefiber composites. In this research, density, composition ratio, and mat moisture content were established as processing variables, and emulsified MAPP prepared by direct pressure method was incorporated as the coupling agent. And the turbulent air mixer, which was improved in function through alteration of our previous fiber mixer, was used to mix wood fibers and polypropylene fibers. At the addition level of 1% MAPP, based on oven-dried wood fiber weight, woodfiber-polypropylenefiber composites generally showed enhanced the physical and mechanical properties. And composites with low to medium densities of 0.6 to 0.8g/$cm^3$ greatly increased in these property values than with high densities of 1.0g/$cm^3$ or more by adding 1 % MAPP. Thus, MAPP addition was thought to be an effective way of enhancing properties for nonwoven web composites. At the mat moisture contents of 5 to 20%, however, the physical and mechanical properties were not enhanced by adding 1% MAPP. In the composites containing 15% polypropylene fibers, the lowest thickness swelling and water absorption values were observed at the 1% MAPP level. The addition of more than 1% MAPP had the adverse effect on the physical and mechanical properties of composites.

• 한국산림과학회지
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• 제13권1호
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• pp.67-78
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• 1971

우리나라에서 황폐산지(荒廢山地)를 복구녹화(復舊綠化)하기 위하여 시행(施行)되고 있는 산복공중(山腹工中)에서 가장 Weight를 많이 찾이 하고 있는 산복공작물(山腹工作物)은 입지공(立芝工)인데, 입지공(立芝工)은 상하계단(上下階段) 간사면라지(間斜面裸地)를 식피조성(植被造成)하지 못하는 시공자체(施工自體)의 취약점(脆弱點)을 가지고 있다. 입지공(立芝工)이 가진 이러한 단점(短點)을 보완해결(補完解決)하며, 나아가서 급경사(急傾斜)의 황폐침식(荒廢浸蝕)된 산복(山腹)에 속성식피조성(速成植被造成)을 기(期)할 수 있는 효과적(効果的)인 산복녹화공법(山腹綠化工法)을 개발(開發)하고저, 급경사(急傾斜)의 점토질(粘土質) 토양사면(土壤斜面) (사면장(斜面長) 1.6m)에 특별(特別)히 조립(組立)한 볏짚거적 (피복율(被覆率) 약(約) 70%)을 피복(被覆)하고 볏짚거적덮기공이 지표토양유실량(地表土壤流失量) 및 토양수분함유량(土壤水分含有量)과 식피조성(植被造成)에 미치는 효과(効果)를 측정(測定)(측정기간(測定期間) 5~9월(月))한바 그 결과(結果)는 대체로 다음과 같이 요약(要約)될 수 있다. 1. 볏짚거적덮이공이 지표토양유실방지(地表土壤流失防止)에 미치는 효과(効果): 일(一) 각처리별(各處理別) 지표토양유실량(地表土壤流失量)의 합계량(合計量) (표(表) 3참조)은 파종후무피복구(播種後無被覆區)$T_1$에서 4,651 g/$1.6m^2$, 파종후피복구(播種後被覆區)$T_2$에서 163 g/$1.6m^2$, 그리고 피복후파종구(被覆後播種區)$T_3$에서 2, 891 g/$1.6m^2$로 측정(測定)되어, $T_2$는 $T_1$의 약(約)28.5배(倍), $T_3$의 17.7배(倍), 또 $T_3$는 $T_1$의 약(約) 1.6배(倍)의 지표토양유실방지효과(地表土壤流失防止効果)가 인정(認定)되었다. (표(表) 2, 3 및 4참조) 2. 볏짚거적덮기공이 사면토양수분함유량(斜面土壤水分含有量)에 미치는 효과(効果): 일처리별(一處理別) 지표면평균토양수분함유량(地表面平均土壤水分含有量)은 $T_1$=21.60%, $T_2$=23.04%, $T_3$=22.21%, 또 지표하(地表下)에서의 그것은 $T_1$=23.81%, $T_2$=26.16% 및 $T_3$=24.81%로 측정(測定)되어, 볏짚거적덮기공이 사면토양수분함유량(斜面土壤水分含有量)에 미치는 효과(効果)에 있어서 고도(高度)의 유의성(有意性)이 인정(認定)되었다. (표(表) 7, 8 및 9 참조) 3. 볏짚거적덮기공이 사면식피조성(斜面植被造成)에 미치는 효과(効果): 일(一) 처리별(處理別) 평균발아본수(平均發芽本數)는 $T_1$=237본(本), $T_2$=246본(本) 및 $T_3$=262본(本)으로 조사(調査)되었으며, 식피율(植被率)(무성기(茂盛期))은 각처리(各處理) 모두 90% 정도(程度)로써 볏짚거적덮기공이 사면식피조성(斜面植被造成)에 미치는 효과(効果)에 있어서는 유의성(有意性)이 인정(認定)되지 아니하였다. 4. 이상(以上)의 결과(結果)를 종합(綜合)해 볼 때에 볏짚거적덮기공은 황폐침식(荒廢浸蝕)된 산복사방공법(山腹砂防工法)으로써 뿐만 아니라 붕양지(崩壤地)와 절개지(切開地)의 사면방호공법(斜面防護工法)으로써 유효(有効)하게 적용(適用)할수 있을것이며, 특(特)히 황폐산지유역(荒廢山地流域)으로부터의 지표토사유실방지상(地表土砂流失防止上) 중요(重要)한 사면녹화공법(斜面綠化工法)이 될 것이다. 5. 본인(本人)은 본(本) 공종(工種)을 새로운 사면녹화공(斜面綠化工)으로써 "볏짚거적덮기공"이라고 호칭(呼稱)하고저 한다.