• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.263-267
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• 2008

This study was performed to compare the efficacy of carboxymethylchitosan fabric (CMCF) with that of the combination of CMCF and low molecular weight heparin (LMWH) for the prevention of postoperative uterine adhesion in rats. Adhesions were induced by suturing both the uterine serosa and peritoneum abrased until petechial bleeding occurred. Fourteen days later, adhesions were evaluated clinically and histopathologically. The mean tensile strength was significantly decreased in the CMCF and CMCF+LMWH groups compared to that of control group, and the CMCF+LMWH group had the lowest tensile strength. The distance of adhesion site was highest in the CMCF group and slightly decreased in the CMCF+LMWH group comparing to that of control group. The inflammatory cell infiltration and neovascularization of the CMCF group were significantly lower than those of the control group. It was observed that the damage at intestinal serosa was significantly decreased in the CMCF+LMWH group comparing to that of control group. Therefore, it was concluded that CMCF and LMWH may be useful to prevent postoperative uterine adhesion in rats.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.141-144
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• 2005

Sensing and interfacial evaluation of Ni nanowire strands/polymer composites were investigated using Electro-micromechanical technique. Electro-micromechanical techniques can be used as sensing method for micro damage, loading, temperature of interfacial properties. Using Ni nanowire strands/silicone composites with different content, load sensing response of electrical contact resistivity was investigated under tensile and compression condition. The mechanical properties of Ni nanowire strands with different type/epoxy composites were measured using uniformed cyclic loading and tensile test. Ni nanowire strands/epoxy composites showed humidity and temperature sensing within limited ranges, 20 vol% reinforcement. Some new information on temperature and humidity sensing plus loading sensing of Ni nanowire strands/polymer composites could be obtained from the electrical resistance measurement as a new concept of the nondestructive interfacial evaluation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.1
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• pp.26-32
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• 2007

This study was carried out fusion-welded butt joints in SWS 490A high strength steel subjected to tensile test that load-deflection curve. The windowed or short-time Fourier transform(WFT or STFT) makes possible for the analysis of non-stationary or transient signals into a joint time-frequency domain and the wavelet transform(WT) is used to decompose the acoustic emission(AE) signal into various discrete series of sequences over different frequency bands. In this paper, for acoustic emission signal analysis to use a continuous wavelet transform, in which the Gabor wavelet base on a Gaussian window function is applied to the time-frequency domain. A wavelet transform is demonstrated and the plots are very powerful in the recognition of the acoustic emission features. As a result, the technique of acoustic emission is ideally suited to study variables which control time and stress dependent fracture or damage process in metallic materials.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1032-1042
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• 1998

The purpose of this study is to measure, compare, and investigate the physical properties of rayon/cotton blend fabrics treated with cellulase and cellulase & specific degeneration silicon and to present basic data which is in development a value-added fabric. The results are as follows. The condition for the treatment of cellulase was at 55$^{\circ}C$, pH 4 and the weight loss increased as the concentration of cellulase and the treated time increased. On treatment with cellulase, the crossectional view & longitudinal view of fiber noticed remarkable crack as weight loss increased and tensile strength and elongation decreased, and pilling was enhanced remarkably. KOSHI was increased, NUMERI and FUKURAMI were decreased as weight loss increased. In the basic characteristic value of clothing wearning, shape stability and drapability were decreased, but air content was improved. On treatment with cellulase & silicon, the degree of damage in the crossectional view & longitudinal view of the fiber reduced. Tensile strength, elongation, moisture regain improved. KOSHI and FUKURAMI were reduced, NUMERI was improved rather than when it was treated with cellulase. Therefore handle was improved. In the basic characteristic value of the clothing wearing, shape stability, air content, drapability were improved.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.45-50
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• 2014

PURPOSES : The objective of this study is to analyze the performance of anti-stripping agent depending on its type and content to reduce pothole, an increasing pavement distress due to abnormal climate intensity. METHODS : In the past years, U.S and many countries in Europe use hydrated lime and liquid anti-stripping agent in asphalt mixtures. Hydrated lime or liquid anti-stripping agent is substituted for filler and binder, respectively, to improve the anti-stripping property of asphalt mixtures. To investigate this, indirect tensile strength test was performed and TSR values were compared for different content of hydrated lime and types of liquid anti-stripping agent in asphalt mixture. RESULTS : Test results indicate that hydrated lime remarkably increased the asphalt mixture performance on anti-stripping denoted by the increased in TSR values from 55% to 100%. Liquid anti-stripping agent also increased the value of TSR but not significant. In addition, depending on the types of aggregate, TSR values and effect of liquid anti-stripping were different. CONCLUSIONS : Using anti-stripping agents improve the anti-stripping property of asphalt mixture especially hydrated lime; however, more experiments should be conducted to improve the reliability about the effect of liquid anti-stripping agent.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.31-39
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• 1997

This research is to evaluate the effect of sunshine treatment on the strength in the Al 6061/AFRP hybrid composite(APAL). APAL specimens were processed by autoclave curing system under the constant condition of curing temperature, time and aluminum surface pertreatment. Aramid patched aluminum alloy can be widely used for the repair of the damage part of the aircraft. The tensile strength of the sunshine treated APAL 2P and 6P composite is 14%, 22% smaller than that of the non-treated material. The interlaminar shear strength of the APAL specimens for the adhesive length of 5mm is 24% higher than that of the APAL for the adhesive length of 10mm. In the case of APAL DS 1P material, interlaminar shear strength of the specimen which was sunshine treated for 200 hours is 21% smaller than that of the non-treated material while interlaminar shear strength of the specimen which was immersed in a 70.deg. C fresh water for 1200 hours decreases by 75.7%.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.40-48
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• 2004

The object of this study is to investigate the effect of joinability by using acoustic emission (AE) signals and doing a pattern recognition for weld heat affected zone (HAZ) in tensile testing. This study was carried out an SWS 490A high tension steel for electric shielded metal arc welding (SMAW), $CO_2$ gas arc welding and TIG welding. And correspondingly, the root openings are 3, 4 and 2.8mm. The results of the tensile test of weld HAZ come out electric shield arc welding > $CO_2$ gas arc welding > TIG welding in case of single welding. It is believed that this is a phenomenon where difference of its root opening or base metal thickness. Also, the technique of AE is ideally suited to study variables which control time and stress dependent fracture or damage process in metallic materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.474-481
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• 2009

Fracture models and criteria of adhesive with two parameters, namely $G_C$ and ${\sigma}_{max}$, have been developed to describe the fracture process of adhesive joints. Cohesive zone model(CZM) is a representative two parameter failure criteria approach. In CZM, ${\sigma}_{max}$ is a critical, limiting maximum value of the stress in the damage zone ahead of the crack and is assumed to have some physical significance in adhesive failure. Based on CZM and finite element analysis method, the relationship between fracture load and adhesive properties, as $G_{IC)$ and $({\sigma}_{max})_I$, was investigated in adhesively bonded joint tensile test and T-peel test. The two parameters in tensile mode loading were evaluated by using the relationship. The value of $G_{\IC}$ evaluated by proposed method showed close agreement with analytical solution for tapered double cantilever beam(TDCB) test which proposed in an ASTM standard.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.105-114
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• 1989

This study was carried out to measure the mechanical properties and the acoustic emission (AE) characteristics of the carbon fiber reinforced composites of several types of the stacking sequence. AE signals were detected during the tensile tests. The number of ringdown counts, total ringdown counts were plotted together with the load-displacement curves. The tensile load-displacement behavior of specimen is compared and discussed based on the measured AE properties in relation to the failure mechanism. With the increase of load, AE signals increased. This showed that failure had being propagated by matrix deformation and cracking, delamination, fiber debonding and breakage. Felicity ratio has been obtained by observation of ;the Kaiser effect according to the variation of load ratio. The reloading tests showed that the felicity ratio decreased obviously when the load ratio or damage increased. These AE characteristics are hopeful to be employed as the criteria to evaluate the failure processes of composites.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1331-1346
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• 2016

Historical masonry structures have an important value for cultures and it is essential for every society to strengthen them and confidently transfer to the future. For this reason, determination of the seismic earthquake response, which is the most affecting factor to cause the damage at these structures, gain more importance. In this paper, the seismic earthquake behaviour of Kaya Çelebi Mosque, which is located in Turkey and the restoration process has still continued after 2011 Van earthquake, is determined. Firstly the dynamic modal analysis and subsequently the seismic spectral analysis are performed using the finite element model of the mosque constructed with restoration drawings in SAP2000 program. Maximum displacements, tensile, compressive and shear stresses are obtained and presented with contours diagrams. Turkish Earthquake Code and its general technical specifications are considered to evaluate the structural responses. After the analyses, it is seen that the displacements and compressive/shear stresses within the code limits. However, tension stresses exceeded the maximum values at some local regions. For this mosque, this is in tolerance limits considering the whole structure. But, it can be said that the tension stresses is very important for this type of the structures, especially between the stone and mortar. So, some additional strengthening solutions considering the originality of historical structures may be applicable on maximum tensile regions.