• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.9
• /
• pp.765-774
• /
• 2009

Fiber Dyeing and Finishing facility has been recognized as an important pollution source due to its consumption of large volumes of water and chemicals. Unit mass discharge for the conventional water quality parameters such as flowrate, SS, $BOD_5,\;COD_{Mn},\;COD_{Cr}$, TN, TP were estimated. To represent the respective industries, three companies were carefully selected based on its manufacturing goods, flowrate and location at various unit operations and processes. More than 90% of decrease in unit mass estimation between influent and effluent of BOD was observed. But the values themselves were similar to those of Fiber Manufacturing facility due to the high loadings of organic matter. Biodegradability of influent was almost three times higher than that of effluent. Unit mass discharge estimations of unit process (estimated in this study) based on space, products and raw material were similar to those of composite process (estimated by National Institute of Environmental Research), while big difference was observed in the other factors. Unit mass discharge factors calculated in this study can be used as the reference for the estimation of water pollution loading costs in Nakdong river basin. For the effective water pollution control and management, it is essential to characterize the various types of water quality parameters from the effluents of individual industrial wastewater treatment plants.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5A
• /
• pp.317-325
• /
• 2012

In this study, to evaluate the shrinkage behavior of ultra high performance fiber reinforced concrete (UHPFRC) under restrained condition, restrained shrinkage test was performed according to ring-test mostly used at home and abroad. Ring-test was performed with the various thicknesses and radii of inner steel ring to give different degree of restraint. Free shrinkage and tensile tests were carried out simultaneously to estimate the degree of restraint, stress relaxation, and shrinkage cracking potential. Test results indicated that the average steel strain and residual tensile stress were reduced as the thicker inner steel ring was used, whereas degree of restraint was increased. The steel strain, residual tensile stress and degree of restraint were hardly affected by the size of radius of inner ring. In the case of all ring specimens, shrinkage crack did not occur because the residual tensile stress was lower than the tensile strength. About 39~65% of the elastic shrinkage stress was relaxed by the sustained interface pressure, and the maximum relaxed stress was increased as the thicker inner ring was applied. Finally, the degree of restraint with age was predicted by performing non-linear regression analysis, and it was in good agreement with the test results.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.6
• /
• pp.516-521
• /
• 2004

The straw of thirty one rice varieties were evaluated for their feed value and related agronomic traits. The rice straw were hand-harvested, dried to constant weight at $75^{\circ}C$ and ground through a 20 mesh seive in a Wiley mill, analyzed with crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF). Relative feed value (RFV) was calculated from NDF and ADF. The sum of standardized score was estimated by dry weight of rice straw, content of CP, ADF and NDF. The straw yield of Daeanbyeo was 725.9 kg/10a, showed heighest value among the varieties and remainder was in the order of Keumnambyeo, Donginbyeo #1 and Chucheongbyeo. Crude protein (CP) content in a Dasanbyeo was higher than those in other varieties. The content of ADF in a Junghwabyeo and NDF in a Sobaegbyeo were $34.3\%$ and $63.8\%$, respectively, showed lowest value among the varieties. The rice straw of Dunnaebyeo, Obongbyeo, Seoanbyeo, Keumobyeo, Hwaseongbyeo, Noganbyeo and Gyehwabyeo belonged to the high feed value varieties by estimation of cluster analysis, sum of standardized score and RFV. The content of CP was found to be positively related with dry weight of leaf and grain, but negatively related with heading days after seeding, culm length, specific leaf weight (SLW) and dry weight of stem. ADF and NDF were found to be positively related with heading days after seeding, culm length, SLW and dry weight of leaf, but negatively related with dry weight of stem. The sum of standardized score and RFV were the only positive relationship with dry weight of stem and negative relationship with other traits.

• Science of Emotion and Sensibility
• /
• v.14 no.2
• /
• pp.207-220
• /
• 2011

The purpose of this study is to investigate sensibility words related with eco-friendly in the two media fashion magazines and internet newspapers and to analysis their appearance frequency and changes by the year through 1999~2010. Most frequently used words are 'nature, eco, cotton, natural fiber, health, fresh, clear, preservation, harmony, com fiber, and Lohas'. The words are divided in 4 groups: 'Nature/Environment, Material/Fiber, Human, and Adjectives/Micell'. A point of appearing time is analyzed: 'ecology, memory-shape material, organic, spa' were used before 2000, 'nature environment, eco-friendly, stretch material, wellbeing, substitute, recycling' were in 2000-2001, 'smart material, eco material, green' in 2002-2003, 'coolbiz, Lohas, natural dye' in 2004-2005, 'herb medicine, sustainable, warmbiz' in 2006-2007, 'greensumer, greenlife, solar energy, forest bath' in 2008-2009. Looking into their changes, in early 2000, the words of eco-friendly emotion and sensibility had appeared frequently relatively, but later on they decreased, and again recently increased showing highest appearing frequency. 'Nature/Environment' words have appeared recently very much, while 'Human' sensibility words have not changed much or decreased a little. 'Adjective/Micell' words has increased little bit recently. 'Material/Fiber' words showed decrease at fashion magazine, while they increased at the pages of internet news.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.6
• /
• pp.78-86
• /
• 2014

In this paper, a novel intensity-based fiber optic vibration sensor using a mass-spring structure, which consists of four serpentine flexure springs and a rectangular aperture within a proof mass, is proposed and its feasibility test is given by the simulation and experiment. An optical collimator is used to broaden the beam which is modulated by the displacement of the rectangular aperture within the proof mass. The proposed fiber optic vibration sensor has been analyzed and designed in terms of the optical and mechanical parts. A mechanical structure has been designed using theoretical analysis, mathematical modeling, and 3D FEM (Finite Element Method) simulation. The relative aperture displacement according to the base vibration is given using FEM simulation, while the output beam power according to the relative displacement is measured by experiment. The simulated sensor sensitivity of $15.731{\mu}W/G$ and detection range of ${\pm}6.087G$ are given. By using reference signal, the output signal with 0.75% relative error shows a good stability. The proposed vibration sensor structure has the advantages of a simple structure, low cost, and multi-point sensing characteristic. It also has the potential to be made by MEMS (Micro-Electro-Mechanical System) technology.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.88-91
• /
• 2002

The two dimensional size effect of specimen gauge section (length x width) was investigated on the compressive behavior of a T300/924 [45/-45/0/90]3s, carbon fiber-epoxy laminate. A modified ICSTM compression test fixture was used together with an anti-buckling device to test 3mm thick specimens with a 30$\times$30, 50$\times$50, 70$\times$70, and 90mm$\times$90mm gauge length by width section. In all cases failure was sudden and occurred mainly within the gauge length. Post failure examination suggests that $0^{\circ}$ fiber microbuckling is the critical damage mechanism that causes final failure. This is the matrix dominated failure mode and its triggering depends very much on initial fiber waviness. It is suggested that manufacturing process and quality may play a significant role in determining the compressive strength. When the anti-buckling device was used on specimens, it was showed that the compressive strength with the device was slightly greater than that without the device due to surface friction between the specimen and the device by pretoque in bolts of the device. In the analysis result on influence of the anti-buckling device using the finite element method, it was found that the compressive strength with the anti-buckling device by loaded bolts was about 7% higher than actual compressive strength. Additionally, compressive tests on specimen with an open hole were performed. The local stress concentration arising from the hole dominates the strength of the laminate rather than the stresses in the bulk of the material. It is observed that the remote failure stress decreases with increasing hole size and specimen width but is generally well above the value one might predict from the elastic stress concentration factor. This suggests that the material is not ideally brittle and some stress relief occurs around the hole. X-ray radiography reveals that damage in the form of fiber microbuckling and delamination initiates at the edge of the hole at approximately 80% of the failure load and extends stably under increasing load before becoming unstable at a critical length of 2-3mm (depends on specimen geometry). This damage growth and failure are analysed by a linear cohesive zone model. Using the independently measured laminate parameters of unnotched compressive strength and in-plane fracture toughness the model predicts successfully the notched strength as a function of hole size and width.

• Composites Research
• /
• v.29 no.2
• /
• pp.45-52
• /
• 2016

An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

• Applied Microscopy
• /
• v.25 no.4
• /
• pp.26-51
• /
• 1995

The present study was designed to examine effect of long term weight-training on aging atrophy in the rat skeletal muscle. Male rats of 8, 15, and 24 month old were used. Each age groups included control and weight-training for 5 months by using body press apparatus. The histo- and cytochemical, ultrastructural and stereological changes in aging skeletal muscles of the rat were observed in the present study. During the training period the body weight and muscular weight in all groups except the rectus femoris and the gastrocnemius in young age groups remained constant, but muscular weights were increased in the rectus femoris and the gastrocnemius muscles in young age groups. In trained rat, the volume density of muscle fiber type IIA and IIB were increased, but those of type IIC was decreased. Type I remained constant in 8 and 15 month old age groups, but reduced in the tibialis anterior and the gastrocnemius muscles in the 24 month old groups. Some histotological and ultrastructural changes associated with age were found: numerical increase of cytiplasmic vacuoles, lysosomes, lipofuscins, and irregularity of myofibrils. At 24 month old groups some unusual formation of contraction band and muscle splitting were observed. After weight-training, ultrastructural degenerative changes occured in the type I muscle fiber, such as splitting of muscle fiber, disorganization of myofilaments, swelling of mitochondria, accumulation of many lipid droplets, appearance of many lysosomes and residual bodies and necrotic fibers, in the old age groups. But, in the type II muscle fibers hypertrophy of muscle fiber appeared without any noticible damage as the type I. The activities of $Mg^{++}$ -ATPase decreased with age and this enzyme activities in the trained rat were significantly decreased with age. Activities of the acid phosphatase were increased with age and significantly in the trained rat. In stereological analysis, volume density of the myofibrils and the tubular system were increased, on the other hand there mitochondrial capacity was decreased. These experimental results suggested that old rats are not susceptible to be affected by weight-training as young rats, and that physical capacity of the rats must be considered when old rats are exercised for training.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.6
• /
• pp.807-817
• /
• 2008

Steers with ad libitum access to rice straw were assigned to four diets to evaluate the effects of maize or soybean hull supplementation on intake, in vivo digestibility, ruminal pH, VFA, ammonia-nitrogen ($NH_3-N$) and in situ ruminal disappearance of feed nutrients by cattle consuming rice straw. Supplement treatments were: no supplement (RS); soybean meal at 0.127% BW (SBM); cracked maize at 0.415% BW plus 0.044% BW soybean meal (MAIZE); or soybean hulls at 0.415% BW plus 0.044% BW soybean meal (HULLS). The MAIZE and HULLS diets were formulated to provide approximately 4 MJ of $NE_m$ per kg of diet. Rice straw DMI was not affected (p = 0.34) by supplement. Apparent dry matter (DM) digestibility was greater (p<0.001) for MAIZE and HULLS (56.6 and 60.0%, respectively) than for steers consuming SBM or RS (51.8 and 44.4%, respectively). Apparent NDF digestibility was greater (p<0.0004) for HULLS than MAIZE (61.7 vs. 58.0%, respectively) and apparent ADF digestibility was greater (p<0.0008) for HULLS than MAIZE (61.1 vs. 49.2%, respectively). There was no difference in apparent hemicellulose digestibility (p = 0.43). Analysis of ruminal fluid collected 0, 2, 4, 6, and 8 h post-feeding revealed ammonia-nitrogen was greatest (p<0.05) for steers on SBM and HULLS diets at 2 h (24.08 and 22.57 mg/dl, respectively) and total volatile fatty acids was greatest (p<0.05) for HULLS at 4 h (230 mM/L). In situ disappearance, measured at 0, 2, 4, 6, 8, 16 and 24 h, indicated that SBM, MAIZE and HULLS tended to enhance the digestibility of DM and fiber components of rice straw. In situ disappearance of rice straw DM was greatest for SBM and/or HULLS from 4 to 24 h (p = 0.03). Rice straw NDF and ADF disappearance was enhanced by supplementation from 16 to 24 h (p<0.02). Rice straw DM, NDF and ADF disappearances at 24 h were similar for MAIZE and HULLS treatments. When feeding cattle rice straw diets, energy and protein-based supplements are essential. This study showed that fiber-based supplements are just as, if not more, effective as starch-based supplements in rice straw utilization. This study shows that soybean hulls, in spite of their high fiber content, are as efficient as maize for supplementing rice straw primarily because fiber in soybean hulls is highly digestible as shown by in vivo digestibility and in situ disappearance.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.1
• /
• pp.45-52
• /
• 2015

Fiber-reinforced polymer (FRP) has been generally accepted by civil engineers as an alternative for steel reinforcing bars (rebar) due to its advantageous specific tensile strength and non-corrosiveness. Even though some glass fiber reinforced polymer (GFRP) rebars are available on a market, GFRP is still somewhat uncompetitive over steel rebar due to their high cost and relatively low elastic modulus, and brittle failure characteristic. If the price of component materials of GFRP rebar is not reduced, it would be another solution to increase the performance of each material to the highest degree. The tensile strength generally decreases with increasing diameter of FRP rebar. One of the reasons is that only fibers except for fibers in center resist the external force due to the lack of force transfer and the deformation of only outer fibers by gripping system. Eliminating fibers in the center, which do not play an aimed role fully, are helpful to reduce the price and finally FRP rebar would be optimized over the price. In this study, the effect of the hollow section in a cross-section of a GFRP rebar was investigated. A GFRP rebar with 19 mm diameter was selected and an analysis was performed for the tensile test results. Parameter was the ratio of hollow section over solid cross-section. Four kinds of hollow sections were planned. A total of 27 specimens, six specimens for each hollow section and three specimens with a solid cross-section were manufactured and tested. The change by the ratio of hollow section over solid cross-section was analyzed and an optimized cross-section design was proposed.