• Geomechanics and Engineering
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• 제18권4호
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• pp.427-437
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• 2019

Waste materials are being produced in huge quantities globally, and the usual practice is to dump them into legal or illegal landfills. Recycled tiles (RT) are being used in soil stabilisation which is considered as sustainable solution to reduce the amount of waste and solve the geotechnical problems. Although the stabilisation of soil using RT improved the soil properties, it could not achieve the standard values required for construction. Thus, this study uses 20% RT together with low cement content (2%) to stabilise soft soil. Series of consolidated undrained triaxial compression tests were conducted on untreated and RT-cement treated samples. Each test was performed at 7, 14, and 28 days curing period and 50, 100, and 200 kPa confining pressures. The results revealed an improvement in the undrained shear strength parameters (cohesion and internal frication angle) of treated specimens compared to the untreated ones. The cohesion and friction angle of the treated samples were increased with the increase in curing time and confining pressure. The peak deviator stress of treated samples increases with the increment of either the effective confining pressures or the curing period. Microstructural and chemical tests were performed on both untreated and RT-cement treated samples, which included field emission scanning electron microscopic (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX). The results indicated the formation of cementation compounds such as calcium aluminium hydrate (C-A-H) within the treated samples. Consequently, the newly formed compounds were responsible for the improvement observed in the results of the triaxial tests. This research promotes the utilisation of RT to reduce the amount of cement used in soil stabilisation for cleaner planet and sustainable environment.

• Composites Research
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• 제27권4호
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• pp.168-173
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• 2014

2개 이상의 에폭시 기지재의 배합비를 이용하여 최적의 에폭시 복합재료를 제조하였다. 이 실험에서 노볼락계 에폭시 및 아이소시아네이트계 에폭시를 기지재로 사용하였다. 그에 따라 화학적 조성의 변화를 이용하여 다양한 실험을 통한 최적의 에폭시 배합비를 유추하였고, 에폭시의 내열성 및 계면을 파악하기 위하여 열중량측정기를 이용하여 유리전이온도의 변화를 파악하였고 정적 접촉각을 측정하였다. 기계적 물성을 파악하기 위하여 에폭시 배합비에 따른 유리섬유/에폭시 복합재료의 인장, 압축, 굴곡강도를 상온에서 및 노화시간에 따라 파악하였다. 에폭시와 유리섬유간 계면을 개념도로 나타냈다. 시험 결과 에폭시 배합비에 따른 적외선 피크 및 유리전이온도 변화를 확인하였다. 서로 다른 에폭시의 배합비가 1:1일 때 기계적물성이 상대적으로 좋은 것을 확인하였다.

• 한국재료학회지
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• 제28권4호
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• pp.254-259
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• 2018

General D-glass(Dielectric glass) fibers are adaptable to PCBs(Printed circuit boards) because they have a low dielectric constant of about 3.5~4.5. However, very few papers have appeared on the physical characteristics of D-glass fibers. D-glass fibers were fabricated via continuous spinning process using bulk D-glass. In order to fabricate the D-glass, raw materials were put into a Pt crucible, melted at $1650^{\circ}C$ for 2 hrs, and then annealed at $521{\pm}10^{\circ}C$ for 2 hrs. We obtained transparent clear glass. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of $1368^{\circ}C$ to $1460^{\circ}C$, while the winder speed was between 100 rpm and 200 rpm. We investigated the physical properties of the D-glass fibers. The average diameters of the glass fibers were measured by optical microscope and FE-SEM. The average diameters of the D-glass fibers were 21.36 um at 100 rpm and 34.06 um at 200 rpm. The mechanical properties of the fibers were confirmed using a UTM(Universal materials testing machine). The average tensile strengths of the D-glass fibers were 467.03 MPa at 100 rpm and 522.60 MPa at 200 rpm.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1293-1297
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• 2016

Cholangiocarcinoma (CCA) is a serious problem in Thailand, particularly in the northeastern and northern regions. Database of population at risk are need required for monitoring, surveillance, home health care, and home visit. Therefore, this study aimed to develop a geographic information system (GIS) database and Google map of the population at risk of CCA in Mueang Yang district, Nakhon Ratchasima province, northeastern Thailand during June to October 2015. Populations at risk were screened using the Korat CCA verbal screening test (KCVST). Software included Microsoft Excel, ArcGIS, and Google Maps. The secondary data included the point of villages, sub-district boundaries, district boundaries, point of hospital in Mueang Yang district, used for created the spatial databese. The populations at risk for CCA and opisthorchiasis were used to create an arttribute database. Data were tranfered to WGS84 UTM ZONE 48. After the conversion, all of the data were imported into Google Earth using online web pages www.earthpoint.us. Some 222 from a 4,800 population at risk for CCA constituted a high risk group. Geo-visual display available at following www.google.com/maps/d/u/0/edit?mid=zPxtcHv_iDLo.kvPpxl5mAs90&hl=th. Geo-visual display 5 layers including: layer 1, village location and number of the population at risk for CCA; layer 2, sub-district health promotion hospital in Mueang Yang district and number of opisthorchiasis; layer 3, sub-district district and the number of population at risk for CCA; layer 4, district hospital and the number of population at risk for CCA and number of opisthorchiasis; and layer 5, district and the number of population at risk for CCA and number of opisthorchiasis. This GIS database and Google map production process is suitable for further monitoring, surveillance, and home health care for CCA sufferers.

• 한국염색가공학회지
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• 제28권1호
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• pp.48-56
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• 2016

Improvement of heat sink technology related to the continuous implementation performance and extension of device-life in circumstance of easy heating and more compact space has been becoming more important issue as multi-functional integration and miniaturization trend of electronic gadgets and products has been generalized. In this study, it purposed to minimize of decline of the heat diffusivity by gluing polymer through compounding of inorganic particles which have thermal conductive properties. We used NH-9300 as base resin and used inorganic fillers such as silicon carbide(SiC), aluminum nitride(AlN), and boron nitride(BN) to improve heat diffusivity. After making film which was made from 100 part of acrylic resin mixed hardener(1.0 part more or less) with inorganic particles. The film was matured at $80^{\circ}C$ for 24h. Diffusivity were tested according to sorts of particles and density of particles as well as size and structure of particle to improve the effect of heat sink in view of morphology assessing diffusivity by LFA(Netzsch/LFA 447 Nano Flash) and adhesion strength by UTM(Universal Testing Machine). The correlation between diffusivity of pure inorganic particles and composite as well as the relation between density and morphology of inorganic particles has been studied. The study related morphology showed that globular type had superior diffusivity at low density of 25% but on the contarary globular type was inferior to non-globular type at high density of 80%.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.461-468
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• 2001

Impact between fruits and other materials is a major cause of product damage in harvesting and handling systems. The oriental pears are more susceptible to bruising than other fruits such as European pears and apples, and are required more careful handling. The interest in the handling of the pears for the processing systems has raised the question of the allowable drop height to which pears can be dropped without causing objectionable damage. Drop tests on pears were conducted using an impact device developed by authors to estimate the allowable drop height without bruising. The impact device was constructed to hold in a selected orientation and to release a fruit by vacuum for dropping on to a force transducer. The drop height was adjustable for zero to 60 cm to achieve the desired distance between the bottom of the fruits and the top of the impact force transducer. The transducer was secured to 150 kg$\sub$f/ concrete block. The transducer signal was sampled every 0.17 ms with a strain gage measurement board in the micro computer where it was digitaly stored for later analysis. The selected sample fruit was Niitaka cultivar of pears which is one of the most promising fruit for export in Korea. The pears were harvested during the 1998 harvest season from an orchard in Daejeon. The sample fruit was selected from two groups which were stored for 3 months and 5 months respectively by the method of current commercial practice. The pears were allowed to stabilize at environmental condition(18$^{\circ}C$, 65% rh) of the experimental room. One hundred fifty six pears were tested from the heights of 5, 7.5. 10 and 12.5 cm while measurement were made of impact peak force, contact time, time to peak force, dwell time, pear diameter and mass. The bioyield strength and modulus of elasticity were measured using UTM immediately after each drop test. The allowable drop height was estimated on the base of bioyield strength of the pears in two ways. One was assumed the peak force during impact test increasing linearly with time, and the other was based on the actual drop test results. The computer program was developed for measuring the impact characteristics of the pears and analyzing the data obtained in the study. The peak force increased while contact times decreased with increasing drop height and contact times of the sample from the hard tissue group. The allowable drop height increased with increasing bioyield strength and contact times, and also varied with Poisson\`s ratio, mass and equilibrium radius of the pears. The allowable drop height calculated by a theoretical method was in the range from 1 to 4 cm, meanwhile, the estimated drop height considering the result of the impact test was in the range from 1 to 6 cm. Since the physical properties of fruits affected significantly the allowable drop height, the physical properties of the fruits should be considered when estimating the allowable drop height.

• 한국식품과학회지
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• 제22권4호
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• pp.380-385
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• 1990

대체염을 사용한 저염식품의 이용가능성을 제시해 보고자 대체염의 상대염도를 조사하고, 혼합염 용액의 관능적 특성 및 혼합염으로 제조한 깍뚜기의 품질 특성을 조사한 결과는 다음과 같이 요약된다. 0.5% NaCl 용액에 대한 $MgCl_2$ 용액과 $K_{2}SO_4$ 용액의 상대염도는 각각 $0.11{\sim}0.12$와 $0.08{\sim}0.09$에 해당하였고 0.5%, 1.0%, 1.5및 2.0% NaCl 용액에 대한 KCI용액의 상대염도는 각각 0.52, $0.55{\sim}0.58$, 0.76 및 0.76에 해당하였다. 혼합염 용액의 관능적 특성을 평가한 결과 KCI의 대체수준이 증가함에 따라 쓴맛, 금속성 향미, 떫은 느낌의 강도가 증가하였다. NaCl의 일부 또는 전부를 KCI로 대체하여 제조한 깍뚜기는 경도, 쓴맛, 신맛, 짠맛, 불쾌한 향미 및 적합성의 모든 관능적 특성에서 유의적인 차이를 나타내었다. pH와 산도는 KCI 대체수준에 따라 유의적인 차이가 없었으며 UTM에 의한 경도측정 결과도 차이를 나타내지 않았다. 이상의 결과로 KCI에 의한 대체율이 50% 이하인 깍뚜기는 NaCl만을 첨가한 깍뚜기와 비교할 때 경도 신맛 및 짠맛에서 큰 차이가 없고 쓴맛과 불쾌한 향미는 비교적 적어서 그 사용 가능성이 크다고 보여지며 앞으로 저염섭취를 위한 방안을 모색하기 위하여 다른 여러 가지 식품에서도 대체염이 이용될 수 있도록 계속적인 연구가 이루어져야 할 것으로 본다.

• Journal of Biosystems Engineering
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• 제27권4호
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• pp.283-292
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• 2002

Mechanical and physical properties of various parts of jujube (Zizyphus jojoba Miller) such as fruits, leaves, secondary branches, and leafy stems were measured and analyzed. The physical dimensions of the fruits were measured using a digital caliper, and the detachment force of the fruit and leafy stems was measured using a force gauge. The physical characteristics of the secondary branches such as the modulus of elasticity and the torsional rigidity were tested using a universal testing machine (UTM). The physical characteristics of leafy stems such as length and weight were also measured using a digital caliper and a digital scale, respectively. The detachment force of leafy stems and the area of the leaf also measured. The terminal velocities of the jujube fruits, leaves, and leafy stems were measured using a custom made terminal velocity experiment system. Diameter of the major and minor axis of the jujube fruit, weight of the fruit, and detachment force of the fruit stem was average of 32.02 mm, 23.92 mm. 10.0 ${\times}$ 10$\^$6/ ㎥, 8.99 g, and 5.43 N. respectively. The detachment forces of the jujube fruits increased and the force-to-weight ratio of the jujube fruits decreased as the weight of the jujube fruits increased. The modulus of elasticity of the secondary branches of the jujube was average of 7.01 ${\times}$ 10$\^$8/ N/㎡ and decreased as diameter of the secondary branches increased. The average torsional rigidity of the secondary jujube branches was 5.2 ${\times}$ 10$\^$-/ N/㎡, and the torsional rigidity decreased as the secondary branch diameter increased. The distribution of the torsional rigidity data associated with the diameter of the branches, however. widely scattered and it was difficult to find any relationship between the diameter of the branches and the torsional rigidity of tile branches. The weight of the leafy stems, number of loaves attached to the leafy stems, diameter of the stem side of the leafy stems, diameter of the leafy stem end was average or 0.7 g, 6.6 ea, 12.2 cm, 4.5 mm, and 2.7 mm, respectively. The major and minor axis of the .jujube loaves, area of leaves, weight of the leaves. and detachment force of the leaves was average of 5.7 cm, 3.3 cm, 12.98 cm$^2$, 0.20 g, and 4.39 N, respectively. The terminal velocity of the .jujube fruits increased as the weight of the fruits increased. The terminal velocity of the leafy stems, however, did not show a relationship with the weight of the leafy stems and the number of leaves attached to the leafy stem. The terminal velocity, however, slightly increased as the length of the leafy stems increased.

• 공업화학
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• 제19권5호
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• pp.471-476
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• 2008

본 연구에서는, 에폭시(DGEBA)/폴리아미드/DDS/2E4MZ-CNS 반응성 블렌드의 폴리아미드 함량에 따른 블렌드계의 열적, 형태학적 특징 및 기계적 물성에 대해 고찰하였다. 본 블렌드계의 경화거동은 DSC, 기계적 강도는 UTM, 형태학적 특징 변화는 SEM, 동적열기계특성은 DMTA를 사용하여 관찰하였다. 폴리아미드의 함량은 각각 10, 20, 30 phr, 경화촉진제인 2E4MZ-CNS의 함량은 2 phr이었으며 반응온도는 $180^{\circ}C$에서 30 min간 유지하였다. 에폭시/폴리아미드/DDS/2E4MZ-CNS 블렌드계는 경화촉진제의 첨가에 의해서 반응 시작 온도가 현저히 낮아지면서 폴리아미드 분산상의 경계면 구분이 어려워지고 co-continuous한 분산상이 관찰된다. 그러나, 경화촉진제가 없을 경우에는 분산상의 경계면이 선명하게 나타난다. 에폭시/폴리아미드/DDS/2E4MZ-CNS 블렌드계는 경화촉진제의 도입에 의해서 반응 온도와 형태학적 특징의 조절이 가능하여 경화촉진제를 사용하지 않는 경우보다 약 20% 높은 기계적 강도를 얻을 수 있었다. 결과적으로, 경화촉진제 도입에 의해서 에폭시와 폴리아미드 분산상 계면에서의 강한 결합력을 기대할 수 있었다.

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.449-455
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• 2011

본 연구에서는 폴리비닐알코올(Polyvinyl alcohol : PVA)와 메틸셀룰로오스(Methyl cellulose: MC)를 사용하여 항균성을 갖는 필름을 제조하였다. 메틸셀룰로오스와 폴리비닐알코올 필름에 항균성을 부여하기 위해 ampicillin(0.025~1wt%)과 streptomycin(0.1~1.0 wt%)을 첨가하여 함량에 따른 기계적인 물성과 항균활성을 확인하였다. 중합도와 검화도에 따른 PVA 필름의 기계적인 물성을 보면 중합도와 검화정도에 따라 필름의 인장강도가 20.2~51.5 $N/mm^2$이었고, 메틸셀룰로오스 필름의 경우 점도에 따라 15.44~21.70 $N/mm^2$이었다. 사용한 균주와 항균제의 함량정도에 따라 그 기계적인 물성과 항균활성에 차이를 보였지만 함량이 늘어날수록 전체적으로 기계적인 물성은 약간 저하되는 경향을 보였지만 항균필름의 항균활성은 우수하였다. Ampicillin과 streptomycin을 사용하여 제조한 항균필름의 항균활성은 포도상 구균과 대장균을 disc diffusion test로 확인하였다. 메틸셀룰로오스와 폴리비닐알코올 필름 모두 streptomycin보다 ampicillin을 함유할 때 항균활성이 우수한 경향을 보였다.