• Composites Research
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• v.36 no.4
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• pp.270-274
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• 2023

The stacking configuration of fiber-reinforced polymer (FRP) composites, achieved via the filament winding process, exhibits distinct variations compared to conventional FRP composite stacking arrangements. Consequently, it becomes challenging to ascertain the influence of mechanical properties based on the typical stacking structures. Thus, it becomes imperative to enhance the mechanical behavior and optimize the interleaved structures to improve overall performance. Therefore, this study aims to investigate the impact of incorporating amorphous halloysite nanotubes (A-HNTs) within different layers of five unique layer arrangements on the low-velocity impact properties of interleaved carbon fiber-reinforced polymer (CFRP) structures. The low-velocity impact characteristics of the laminate were validated using a drop weight impact test, wherein the resulting impact damage modes and extent of damage were compared and evaluated under microscopic analysis. Each interleaved structure laminate according to whether nanoparticles are added was compared at impact energies of 10 J and 15 J. In the case of 10 J, the absorption energy showed a similar tendency in each structure. However, at 15 J, the absorption energy varies from structure to structure. Among them, a structure in which nanoparticles are not added exhibits the highest absorption energy. Additionally, various impact fracture modes were observed in each structure through optical microscopy.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.130-137
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• 2023

This study analyzed the effect of mixing order on the flowability, compressive strength, and flexural strength of cement composites reinforced with polyvinyl alcohol(PVA) fibers and multi-walled carbon nanotubes(MWCNTs). The experimental results showed that the addition of CNTs significantly reduced the flowability, and the flowability was considerably affected by the mixing order when CNTs were added. The compressive strength was most effectively improved when water and CNTs solution were mixed first before adding PVA fibers, and the flexural strength was highest when water and CNTs solution were mixed with PVA fibers after dry mixing. However, there was no clear correlation between the flexural toughness and the mixing order. In addition, scanning electron microscopy(SEM) image analysis was conducted to analyze the microstructure. The SEM images showed that CNTs were randomly dispersed through the specimens and contributed to the strength improvement, but the effect of the mixing order was not clearly observed. The main results of this study are expected to be useful for evaluations of workability and material performance of PVA fiber-reinforced cement composites with CNTs.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.180-190
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• 2016

This prospective pilot clinical trial mainly focuses on developing dual chamber-based assistive cups which are suitable for stroke patients who have struggled with using there affected arms. It is unable to provide motor and sensory enhancement during drinking activities and to examine the feasibility of the devices for acute phase, even for chronic stroke survivors. The stroke patients(n=16; male=8, female=8), in this trial, were provided informed consent to the investigation. All the individuals participated in 1 weeks of training for using cups, randomized over dedicated dual chamber based assistive cups(DC) or placebo-cups(PC) training. All the participants were assessed within 1 week before and after the intervention period. 3-dimensional motion analysis, sEMG(surface electromyography) and 3-dimensional trunk movement were assessed. The result presents DC data group compared with PC showed, they needed lesser ROM(range of motion) at the phase of drinking in shoulder movements and lesser muscle activities on upper trapezius, deltoid middle fiber and triceps brachii muscles, lesser tilting movement on front and back side in drinking phase, the differences were statistically significant(p<.05). Dual chamber-based assistive cup could be one of efficient way to complete ADLs(activities of daily living), especially drinking tasks, and these evidence data may contribute to determine certain rehabilitation policies related to assistive devise usage.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1575-1589
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• 2017

Objective: This study was conducted to determine molecular structures related to carbohydrates and lipid in alfalfa hay cut at early bud, late bud and early flower and in the afternoon and next morning using Fourier transform infrared spectroscopy (FT/IR) and to determine their relationship with alfalfa hay nutrient profile and availability in ruminants. Methods: Chemical composition analysis, carbohydrate fractionation, in situ ruminal degradability, and DVE/OEB model were used to measure nutrient profile and availability of alfalfa hay. Univariate analysis, hierarchical cluster analysis (CLA) and principal components analysis (PCA) were conducted to identify FT/IR spectra differences. Results: The FT/IR non-structural carbohydrate (NSCHO) to total carbohydrates and NSCHO to structural carbohydrate ratios decreased (p<0.05), while lignin to NSCHO and lipid CH3 symmetric to CH2 symmetric ratios increased with advancing maturity (p<0.05). The FT/IR spectra related to structural carbohydrates, lignin and lipids were distinguished for alfalfa hay at three maturities by PCA and CLA, while FT/IR molecular structures related to carbohydrates and lipids were similar between alfalfa hay cut in the morning and afternoon when analyzed by PCA and CLA analysis. Positive correlations were found for FT/IR NSCHO to total carbohydrate and NSCHO to structural carbohydrate ratios with non-fiber carbohydrate (by wet chemistry), ruminal fast and intermediately degradable carbohydrate fractions and total ruminal degradability of carbohydrates and predicted intestinal nutrient availability in dairy cows ($r{\geq}0.60$; p<0.05) whereas FT/IR lignin to NSCHO and CH3 to CH2 symmetric stretching ratio had negative correlation with predicted ruminal and intestinal nutrient availability of alfalfa hay in dairy cows ($r{\geq}-0.60$; p<0.05). Conclusion: FT/IR carbohydrate and lipid molecular structures in alfalfa hay changed with advancing maturity from early bud to early flower, but not during the day, and these molecular structures correlated with predicted nutrient supply of alfalfa hay in ruminants.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.91-99
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• 2017

The purpose of this paper is to evaluate the flexural performance of reinforced concrete (RC) beams repaired with polymer mortar. The repaired and non-repaired 13th beams which was fabricated by considering repair position, repair depth, and curing age of polymer mortar as test variables were tested under three point loading. All specimens repaired in compressive and tensile zone did not fail due to interfacial failure between polymer mortar and concrete but failed when the strain of repaired mortar exceeded the ultimate tensile strain of polymer mortar. Maximum load of specimens repaired in compressive zone was similar to that of non-repaired specimen, reference specimen. Additionally, their ductility index was higher than that of reference specimen. On the other hand, specimens repaired in tensile zone failed very brittlely and have a lower ductility index than reference specimen. Nonlinear analysis by using OpenSees was performed to predict the behavior of RC beam repaired with polymer mortar. Two dimension frame element was used to simplify an analysis model and fiber model was applied to consider the material non-linearity. It was confirmed from the analysis results that nonlinear analysis properly predicts the behavior of specimens repaired in compressive zone and overestimates the behavior of specimens repaired in tensile zone.

• The Research Journal of the Costume Culture
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• v.3 no.2
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• pp.241-260
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• 1995

The Maori's traditional clothing materials, basic forms of dress, and the pattern and technique of tatoo were examined in the present study in order to deepen the appreciation of the cultural heritage of the Maori. The research method employed was the analysis of written materials. And a fild-trip was also made for the study. The study was limitted to the traditional culture of body adornment of the Maori including the clothing which is preserved and practicing by them at the present day, and the origin and the process of the historical development of those are not included in the scope of the present study. Followings are the results of the study: (1) By far the most widely used fiber for Maori clothing is abtained from what is commonly called New Zealand Flax. The fiber of kiekie(Freycinetia baueriana) and cabbage trees(Cordyline spp.) may also be used. The strong, long-lasting fiber of toi(cordyline indivisa) is used for a prestige warrior's cloak. Flat strips of ti kauka(Cordyline australi) are also used as thatch on rain cloaks. (2) Regardless of technique used, Maori weaving is always worked horizontally from left to right. Traditionally the work was suspended between two upright turuturu or weaving sticks. As the work progressed a second pair of uprights was used to keep the work off the ground. These uprights were moved forward as required. Because the weaver sat on the ground, the working edge was kept at a height that was comfortable to reach. No weaving tools are used, the wefts(aho) being manipulated by the fingers. The two main Maori weaving techniques are whatu aho patahi(single-pair twining) and whatu aho rua(double-pair twining). (3) The Maori wore two basic garments - a waist met and a cloak. The cloth of commoners were of plain manufacture, while those of people of rank were superior, sometimes being decorated with feather or dyed tags and decorated borders. Children ran more-or-less naked until puberty, being dressed only for special events. Some working dress consisted of nothing more than belts with leaves thrust under them. Chiefs and commoners usually went barefoot, using rough sandals on journeys over rough country (4) The adornment of men and women of rank was an important matter of tribal concern as it was in chiefly persons that prestige of the group was centred, The durable items of Maori persons adornment were either worn or carried. Ornaments of various kinds were draped about the neck or suspended from pierced earlobes. Combs decorated the head. Personal decorations not only enhanced the appearance of men and women, but many had protective magical function. The most evident personal ornament was the hei-tiki made of jade or other material. Maori weapons were treasured by their owners. They served on bottle and were also personal regalia. A man of rank was not fully dressed without a weapon in hand. Also weapons were essential to effective oratory. (5) No man or woman of rank went without some tattoo adornment except in extremely rare instances when a person was too sacred to have any blood shed. The untattooed were marked as beeing commoners of no social standing. This indelible mark of rank was begun, with appropriate rite and ritual, at puberty. And tattoo marked the person as being of a marriageable age. Maori tattoo was unlike most traditional tattoo in that its main line were 'engraved' on the face with deep cuts made by miniature bone chisels. The fill-in areas were not tattooed with cuts but with the multiple pricks of small bone 'combs' that only lightly penetrated the skin surface. The instrument of tattoo consisted of small pots of pumice or wood into which was placed a wetted black pigment made from burnt kauri gum, burnt vegetable caterpillars or other sooty materials. A bird bone chisel or comb set at right angles on a short wooden handle was dipped into the gigment, that a rod or stick was used to tap head of this miniature adze, causing penetration of the skin surface. Black pigment lodged under the skin took on a bluish tinge. A full made facial tattoo consisted of major spirals with smaller spirals on each side of the nose and sweeping curved lines radiating out from between the brows over the forehead and from the nose to the chin. The major patterns were cut deep, while the secondary koru patterns were lightly pricked into the skin.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.27-35
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• 2014

The headspace solid-phase microextraction (HS-SPME) followed by gas chromatography/mass spectrometry procedure has been developed for the simultaneous determination of petroleum aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) and polycyclic aromatic hydrocarbons (PAHs) in seawater. The advantages of SPME compared to traditional methods of sample preparation are ease of operation, reuse of fiber, portable system, minimal contamination and loss of the sample during transport and storage. SPME fiber, extraction time, temperature, stirring speed, and GC desorption time were key extraction parameters considered in this study. Among three kinds of SPME fibers, i.e., PDMS ($100{\mu}m$), CAR/PDMS ($75{\mu}m$), and PDMS/DVB ($65{\mu}m$), a $65{\mu}m$ PDMS/DVB fiber showed the most optimal extraction efficiencies covering molecular weight ranging from 78 to 202. Other extraction parameters were set up using $65{\mu}m$ PDMS/DVB. The final optimized extraction conditions were extraction time (60 min), extraction temperature (50), stirring speed (750 rpm) and GC desorption time (3 min). When applied to artificially contaminated seawater like water accommodated fraction, our optimized HS-SPME-GC/MS showed comparable performances with other conventional method. The proposed protocol can be an attractive alternative to analysis of BTEX and PAHs in seawater.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.453-462
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• 2018

This study was carried out to investigate the utilization value of legume crops collected in tropical and subtropical areas. We examined agronomic traits to assess domestic adaptability and evaluated useful components of foreign legumes. We used a total of 201 genetic resources of three legumes, consisting of 68 lentils, 72 chickpeas and 61 guars. The average number of days to flowering of the three legumes ranged from 56.7 to 60.8 days; the shortest in guar and longest in chickpea. The average number of days to growth of the three legumes ranged from the shortest 86.8 days in lentil, to the longest 163.9 days in guar. The maturation period of the three legumes lasted from the end of May until mid-September, based on sowing in March. However, the average yield of lentil was very low, ranging from 0.5 g to 30.6 g, with an average 16.4 g based on 10 plants per accession. The average 100 seed weight of the three legumes was 2.2 g for lentil, 22.9 g for chickpea, and 3.8 g for guar. The crude protein content ranged from 14.1% to 32.4% with an average of 20.4%, the highest for guar and the lowest for chickpea. The average crude oil content in the three legume crops was generally low, ranging from 0.8% in lentil, to 4.3% in chickpea. The average dietary fiber content in the three legume crops varied from 15.7% to 50.7%. Guar was the highest source of fiber, followed by chickpea (19.3%) and lentil (15.7%). From the agricultural traits analysis, chickpea and guar could grow domestically. However, lentil was difficult to flower and fruit normally during the warmer season after May. Therefore, lentil should be considered for late summer cropping during the cool season. The physicochemical properties of the three legumes seem to be useful as they are similar to, or better than, those of the control common bean.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.4
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• pp.215-221
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• 2022

This study was carried out to investigate the growth characteristics, yield and chemical compositions of rye according to mixing ratio of chemical fertilize r(CF) and liquid swine manure (LSM) in paddy field cultivation. The experimental design was arranged in a randomized block design with three replications. The manure fertilizer ratio of five treatments were CF 100% + LSM 0% (C), CF 70% + LSM 30% (T1), CF 50% + LSM 50% (T2), CF 30% + LSM 70% (T3), and CF 0% + LSM 100% (T4) of rye. At this time, the application of liquid swine manure was based solely on nitrogen. Plant length did not show significant differences among treatments. Ear length, leaf length and leaf width were the longest in C, T3, and T2, respectively (p<0.05). The stem diameter showed in the order of T4 > T3 > T2 > T1 > C, which was thicker as the LSM application rate increased (p<0.05). Fresh, dry matter and total digestible nutrient (TDN) yield were the highest in T4 (p<0.05), whereas the lowest in C treatment. Crude protein, neutral detergent fiber (NDF), acid detergent fiber (ADF) and crude fiber content were did not show significant difference among treatments. However, compared to C, crude fat and crude ash were significantly higher in T2 and T3, respectively (p<0.05). Total mineral content decreased significantly as the LSM application rate increased (p<0.05). Total free sugar showed high in T3 and T4 with a high LSM ratio, but showed significantly lower in chemical fertilizer treatment (C) and low LSM treatment (T1) (p<0.05). The analysis of all the above results suggests that the application of LSM is very effective, considering the dry matter yield and the contents of free sugar. In addition, LSM may be possible to grow rye without chemical fertilizer.

• Journal of Animal Science and Technology
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• v.59 no.7
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• pp.19.1-19.10
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• 2017

Background: To reduce use of main feed ingredient like corn, soy bean meal (SBM) and wheat, alternative ingredients has been studied like copra meal (CM). Production amount of CM which has been high makes CM to be an alternative feed stuff. However, low digestibility on AA and low energy content by high fiber content can be an obstacle for using CM. This experiment was conducted to evaluate the effects of CM supplementation with ${\beta}$-mannanase on growth performance, blood profile, nutrient digestibility, pork quality and economic analysis in growing-finishing pigs. Methods: A total of 100 growing pigs ([Yorkshire ${\times}$ Landrace] ${\times}$ Duroc) averaging $31.22{\pm}2.04kg$ body weight were allotted to 5 different treatments by weight and sex in a randomized complete block (RCB) design in 5 replicate with 4 pigs per pen. Treatments were 1) Control (corn-SBM based diet + 0.1% of ${\beta}$-mannanase (800 IU)), 2) CM10 (10% copra meal + 0.1% ${\beta}$-mannanase (800 IU)), 3) CM15 (15% copra meal + 0.1% ${\beta}$-mannanase (800 IU)), 4) CM20 (20% copra meal + 0.1% ${\beta}$-mannanase (800 IU)) and 5) CM25 (25% copra meal + 0.1% ${\beta}$-mannanase (800 IU)). Four phase feeding program was used: growing I (week 1-3), growing II (week 4-6), finishing I (week 7-9) and finishing II (week 10-12). Results: In growth performance, there was no significant difference among treatments during whole experimental period. In growingI phase, G:F ratio tended to increase when CM was increased (P = 0.05), but ADG and ADFI tended to decrease in finishingII phase (linear, P = 0.08). Also, increasing CM reduced ADG (linear, P = 0.02) and feed efficiency (linear, P = 0.08) during the whole finishing period. In blood profiles, BUN was linearly increased as CM increased (linear, P = 0.02) at growingII period. In digestibility trial, there was no significant difference in dry matter, crude fat, crude ash and nitrogen digestibility. However, crude protein digestibility was decreased linearly (linear, P = 0.02). In economic analysis, feed cost per weight gain and total feed cost per pig were reduced in overall period when CM was provided by 25% (linear, P = 0.02). Conclusion: CM with 0.1% of ${\beta}$-mannanase (800 IU) could be supplemented instead of corn and SBM up to 25% without detrimental effects on growth performance and pork quality of growing-finishing pigs.