Journal of the Korea Organic Resources Recycling Association
/
v.3
no.2
/
pp.103-114
/
1995
Since autoheated thermophilic aerobic digestion (ATAD) process has various advantages for the treatment of high-strength organic wastewater, active research and field application has been applied in U.S.A. and Canada, recently and the interest in ATAD process has been elevated for treating high-strength organic wastewater efficiently in Korea. Therefore, various experiments were carried out to evaluate the feasibility of ATAD process for the treatment of pig manure wastewater. The results of this study showed possibility to reuse pig manure wastewater as wet fodder or liquid compost, since ATAD process led excellent stabilization on the basis of odor and putrefaction. However. digested sludge can not be provided as wet fodder to most of hog farms without changing dry feeder system into wet system and as liquid compost to hog farms not having their own grass land. Since the results showed that the increase of temperature in reactor was resulted not from energy by biological activity. but from mechanical mixing energy. the reactor investigated in this study was against the principle of ATAD process. Therefore. if pig manure wastewater treated by ATAD can not be utilized as wet fodder. it is not economical to adopt ATAD process only for the treatment of wastewater.
Journal of the Korean association of regional geographers
/
v.5
no.1
/
pp.151-162
/
1999
This study is a comparative analysis of sea level and 500hPa surfaces between dry year and wet year, which are selected by variability of precipitation and standardized anomalies in Korea in early autumn. While the amount of precipitation of early autumn decreases, the variability of precipitation increases rapidly reflecting the strength and weakness of Kaul Changma front and the occurrences of the typhoonic precipitation. The regional distribution of the variability of precipitation shows west-high, east-low pattern in which the east coast and the southeastern coast shows low, but high in the southwestern coast. In the anomalies distribution of sea-level and 500hPa surfaces, during dry year, the northern part of Siberia and the core area of North Pacific high shows negative anomalies, on the contrary, there were positive anomalies in wet year at the same areas. In addition, at the 500hPa level, while the Korean peninsula was located at the west of deep trough with low zonal index in dry year, the peninsula was influenced by weak trough with high zonal index showing strong zonal flow in wet year. During dry year the height of 500hPa surface is low at the north of $40^{\circ}N$, but high in wet year. In consequences, this study identified that the occurrences of dry year and wet year were influenced by the seasonal variations of the strength and the weakness of North Pacific high and Siberian high.
Felekoglu, Kamile Tosun;Felekoglu, Burcu;Tasan, A. Serdar;Felekoglu, Burak
Computers and Concrete
/
v.12
no.5
/
pp.651-668
/
2013
Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.
The effect of silane coupling agents on the water stability of HAC/PVA based MDF cement composites which were modified with urethane and epoxy resin were studied as a function of the functional groups and addition amount of silane coupling agent. According to the composition of polymer matrix the silanes with different functional groups showed the different effectiveness. In case of the only PVA matrix the silane with vinyl functional group was more effective than other silanes. When the epoxy resin was added the silane of epoxy-methodxy group enhanced the flexural strength of dry and wet state more than other. In case of urethane-added MDF cement the silane of diamine group was effective and enhanced the water sta-bility fo MDF cement composite more and more as the addition amount of silane increased, Especially in case of warm-presed composite the effect of silane was enhanced By addition of 2wt% of silane with 야-amine group the flexural strength of urethane-added composites were enhanced by 20% more in dry state 40-70% in wet state in accord with the porosity analysis. The flexural strength of the poxy resin-added MDF cement composite was increased by addition of 1wt% and 2wt% silane of epoxy-methoxy group However the addition of 4wt% of silane decreased the flexural strength of dry and wet state by formation of closed pore in the polymer matrix.
This study was carried out to discuss feasibility of high density polyethylene(HDPE) as a new substitute for the conventional adhesives in plywood manufacture. Plywood was composed of radiata pine(Pinus radiata) and Malas(Homallium feotidium) veneers and bonded by HDPE. Adhesion characteristics and anatomical scanning has been examined through tensile-shear strength test and scanning electron microscopy(SEM). The results are as follows; 1. Optimum loading quantity was 15g/$(30.3{\times}30.3)cm^2$, and tensile-shear strength increased with the increase of loading quantity. 2. Even at the hot pressing time of 1 minute, tensile-shear strength met the value of KS(over the 7.5kgf/$cm^2$), and tensile-shear strength increased with the increase of hot pressing time. 3. Plywood composed of veneer at moisture content of 19.6% showed similar tensile-shear strength to that at air conditioned moisture content of 11.4%. 4. Under the same condition of hot pressing time, tensile-shear strength of plywood bonded by HDPE met the KS value of boil and wet test and proved the same group as phenol formaldehyde adhesive. 5. HDPE films showed mechanical adhesion through penetration into the lathe check and ray of veneer.
Proceedings of the Korean Institute of Building Construction Conference
/
2008.11a
/
pp.49-52
/
2008
The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire-resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire-resistant boards. 1. Improved PF board was prepared by adding inorganic fiber to existing board and using aggregate with grain size of 3mm or less. Molding was done at temperature higher than that for existing PF board molding. While wet curing is used for existing PF boards, this study used dry curing in order to enhance heat insulation performance. 2. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116℃ in 15mm, 103.8℃ in 20mm, and 94℃ in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3-hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.
Proceedings of the Korean Institute of Building Construction Conference
/
2008.05a
/
pp.103-107
/
2008
This study was to execute the experiment for analyzing the quality characteristics of mortar by type of recycled sand by using the recycled sand produced by the manufacturing system by wet gravity separation in order to develop the removal device of impurities for the production of high-quality recycled sand. As a result, this study has sown that the mortar using the high-quality recycled sand through the manufacturing system by wet gravity separation in the fluidity property, strength property, and shrinkage property largely, compared with the mortar using low-quality recycled sand that not passed the device of sand flux. There was a tendency similar to the plane mortar. In conclusion, it was considered as various quality performances of the recycled sand were improved through the production stage of prototype.
Statement of problem. Soft lining materials, also referred to as tissue conditioning materials, tissue heating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. Purpose. The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. Material and Methods. This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the Relation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL.,USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint desist which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the $20{\times}20mm$ transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/ TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. Conclusion. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.
Journal of the Korea institute for structural maintenance and inspection
/
v.28
no.1
/
pp.53-60
/
2024
Compressive strength in concrete has many affecting parameters and varies with exposure conditions. Although the concrete has same mix proportions, its properties are different with exposure conditions, and sea-environment can be classified into three groups such as tidal, atmospheric, and sea submerged region particularly. In this study, compressive strength was evaluated on 7-year-cured concrete and the results from previous equations (KDS, ACI, CEB, and JSCE) were compared with them. Furthermore the strength and carbonation progress were evaluated on concrete cured for 7 years exposed to three different sea environment. Three levels of w/c (water to cement) ratio (0.37, 0.42, and 0.47) and three different exposure conditions (tidal, atmospheric, and submerged) were considered. The results from wet-cured condition are all higher than those from the previously proposed equations, and the results from different sea exposure conditions (tidal, atmospheric, and submerged region) were lower than those from wet-cured condition. A reduction of strength was evaluated with increasing w/c ratio and the minimum strength was evaluated in the sea-submerged conditions. Several experimental constants applicable to the previous equations were obtained from regression analysis since the strength change with w/c ratios were not considered in those equations. Regarding carbonation depth with different exposure conditions, higher carbonation depth clearly was observed with increasing w/c ratios, and evaluated in the order of atmospheric, submerged, and tidal region. Considerable carbonation depth was observed in submerged and tidal region due to sulfate ion and dissloved carbon dioxide as well.
Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
/
2001.11a
/
pp.183-199
/
2001
Alternative way of shaping fibers suitable for papermaking was introduced. Impact refining, which was done simply by hitting wet fibers with a metal weight vertically, was intended to keep the fibers from shortening and to cause mostly internal fibrillation. Virgin chemical pulp, its recycled one and OCC were used in the experiment. It was noticed from the experiment that impact refining on virgin chemical pulp kept the fiber length and Increased bonding properties greatly, However, in the recycled fibers from the chemical pulp, fiber length and bonding properties were decreased. In OCC, which seems to contain fractions of semi-chemical pulp and mechanical pulp (GP), and which is recycled pulp from corrugated boxes, fiber length and bonding properties were decreased disastrously. We believe recycled cellulosic fibers (recycled chemical pulp and OCC in this case), which went through hornification, were less resistant to the mechanical impact than virgin chemical pulp. For virgin chemical pulp, impact refining allowed no significant fiber length shortening, high WRV, and high mechanical strength.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.