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Evaluation of Physical and Mechanical Properties of Non-certificated Laminated Veneer Lumber (LVL) Circulated in Domestic Lumber Market

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.39 no.5
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    • pp.429-436
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    • 2011
  • The selected physical and mechanical properties of non-certificated LVL circulated in domestic lumber market were investigated and compared to relevant standards. The tested LVL passed the moisture content and the soaking delamination rate limit as per domestic (KS) and Japanese standard (JAS). The evaluated mechanical properties were flatwise/edgewise bending strength, modulus of elasticity (MOE), horizontal shear and compressive strength. The 30 mm-thick LVL showed significantly higher bending strength than that of the 25 mm-thick LVL. The modulus of elasticity (MOE) showed same tendency in the results of bending strength. The edgewise bending strength and MOE were higher than that of flatwise bending strength and MOE. The horizontal shear strength values were also showed similar results to bending strength values. The tested results were compared each other and each products were graded according to JAS 701 grade specification. The failure mode of LVL in bending test showed the similar failure mode of solidwood that failed in a simple tension manner (splintery tension). The glue line failure was severe in 25 mm-thick specimens due to concentration of shear stress in layer discontinuity containing small voids and starved glue lines. In horizontal shear strength test, failure mode of LVL showed the typical horizontal shear failure. Compressive specimens failed with fiber crushing in company with apparent delamination that splitted along the length of the specimens. From the results, the complete bonding between lamination and consistency in thin veneer layer were considered as a critical factor in the mechanical properties of LVL. Moreover, the standard test procedure and specification for non-certificated LVL should be required to check the performance of uncertificated materials.

Correlation between Analytic and Experimental Results on Inelastic Behavior of Reinforced Concrete Frame

  • Lee, Han-Seon;Kim, Sang-Dae;Park, Cheol-Yong;Ko, Dong-Woo
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.173-181
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    • 2006
  • The objectives of this study are to evaluate the reliability of an existing nonlinear analysis program for predicting the inelastic behavior of reinforced concrete frame with seismic details and to observe the redistribution of the internal forces, which can not be easily measured by an experiment. In order to carry out this task, the nonlinear analysis program of IDARC 2D(3) was run on a 2-bay, 2-story moment-resisting reinforced concrete plane frame with seismic details. (1) The effort to obtain the results of the analysis similar to those of experiment was made by determining the appropriate values of model parameters. The comparison of the analysis results with those of experiment and the observation of the distribution of internal forces obtained through nonlinear analysis points to the following conclusions. (1) The overall relationship between lateral load and lateral displacement given by the analysis is similar to that of experiment. However, the values of initial stiffness and the amount of energy dissipation in the initial displacement steps given by the analysis show larger values than those of experiment. (2) The analysis provided detailed information on the distribution and redistribution of internal forces and proved useful in elucidating the crack pattern, the sequence of the occurrence of plastic hinges, and the failure or yielding mechanism for the whole structure. (3) In spite of the similarity in overall behavior of analysis and experiment, there exists a significant discrepancy in some local behaviors. Furthermore, the hysteresis in the relationship between moment and curvature in some column ends have shown sudden deteriorations in strength, which can not be interpreted satisfactorily at the present time. Therefore, it is necessary to develop a better analytical model to fill this knowledge gap.

Local ridge augmentation using a composite of bone substitute and collagen membrane at peri-implant dehiscence defects: a clinical, radiographic and histological analyses. (성견에서 차단막/골이식재 복합체를 이용한 임플란트 주위 골유도재생 효과: 임상적, 방사선학적, 조직학적 평가)

  • Song, Young Woo;Yoon, So-Ra;Cha, Jae-Kook;Lee, Jung-Seok;Choi, Seong-Ho;Jung, Ui-Won
    • The Journal of the Korean dental association
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    • v.55 no.10
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    • pp.676-687
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    • 2017
  • Objectives : The aim of this study was to evaluate the effects of a composite of bone substitute and collagen barrier membrane (bone patch) for local ridge augmentation at peri-implant dehiscence defects on the clinical efficacy and positional stability in dogs. Materials and methods : Implant placement and ridge augmentation procedure were performed at surgically created peri-implant dehiscence defects in canine mandible (n=6). Four treatment modalities were randomly applied: i) bone patch group, ii) Guided bone regeneration (GBR) without pin fixation group (bone graft and collagen membrane), iii) GBR with pin fixation group, and iv) negative control group. After 12 weeks, clinical, micro-CT and histological analyses were performed. Results : Histologic analysis showed that bone patch group had similar results to GBR group and GBR with fixation group in terms of new bone formation. Micro-CT analysis revealed similar results to histologic analysis in terms of total volume maintenance. Operating time was shorter in bone patch group compared to GBR group and GBR with fixation groups. Conclusions : GBR using bone patch could simplify the ridge augmentation procedure with reduced operating time and equivalent biological performance compared to the conventional procedure.

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Analysis of Dress Style and Patterns for the Reproduction of Empire Style Dress (엠파이어 시대의 드레스 재현을 위한 형태분석 및 패턴연구)

  • Lee, Jeong-Ran;Jung, Jae-Min;Cho, Youn-Joo
    • Fashion & Textile Research Journal
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    • v.8 no.6
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    • pp.687-696
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    • 2006
  • This study aims at analyzing the silhouette, dress patterns and detail of Empire Era(1789-1825), and making use of this results for the modern stage costume construction. The dresses of Empire era were divided into X and H style. The results revealed that the bust girth of X style group was bigger than that of H style group. Such patterns as high waistline, puff sleeve, train, etc. which appeared during the peak time of Empire style period were more remarkable for H style group. This obviously indicated that more epical characteristics were observed for H style group than for X style group. Similarly to silhouette analysis, based on the results from cluster analysis conducted to put similar groups together, two groups were formed - a visually differentiated and complex group and a simple group in the absence of detail. Most dress details from Empire period had simple embellishments. Comparison of the average size of the patterns between two groups indicated that waist front length of H style was shorter than that of X style. Front interscye was even greater than back width for both groups. Such trend was quite different from today's pattern in which back width is larger than front width based on body measurements. Preference for big breast during the period was reflected on dress patterns and the side length of front side goes across the back much further for bodice patterns. Two representatives were selected and reproduced using materials similar to those of real dresses of Empire style, following two times fit test.

Beyond Limitations: Practical Strategies for Improving Cancer Care in Nigeria

  • Eguzo, Kelechi;Camazine, Brian
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.5
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    • pp.3363-3368
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    • 2013
  • Background: The burden due to cancers is an emerging public health concern especially in resource-limited countries like Nigeria. The WHO estimates that cancer kills more people than tuberculosis, HIV/AIDS and malaria combined. As people in Nigeria and other developing countries are beginning to survive infectious diseases, there is an observed epidemiologic transition to chronic diseases, such as cancers. In 2008, 75 out of 1,000 Nigerians died of cancer. Despite the rising incidence and public health importance, Nigeria lacks an organized and comprehensive strategy to deal with cancers. Materials and Methods: This article reviewed 30 peer-reviewed manuscripts on cancer care in four countries. It highlights the limitations to cancer care in Nigeria; due to lack of awareness, low health literacy, absence of organized screening programs, inadequate manpower (in terms of quality and quantity) as well as limited treatment options. Results: This review led to the formulation of a proposal for Nigerian National Cancer Policy, mainly drawn from effective strategies used in Canada, Brazil and Kenya. This is a vertical cancer program that is patient-centered with an emphasis on tobacco control and cancer disease screening (similar to Canada and Brazil). Additionally, it emphasizes primary cancer prevention (similar to Kenya). Its horizontal integration with other disease programs like HIV/AIDS will improve affordability in a poor resourced country like Nigeria. Capacity building for health professionals, hub-and-spoke implementation of screening services, as well as investment in effective treatment options and increased research in cancer care are essential. International 'twinning collaborations' between institutions in richer countries and Nigeria will enhance effective knowledge translation and improve the quality of patient care. Conclusions: A national cancer policy must be developed and implemented in Nigeria in order to overcome the present limitations which help contribute to the observed increases in cancer morbidity and mortality rates. Cancer control is feasible in Nigeria if the nation was to consider and employ some of the cost-effective strategies proposed here.

Characterization of Large-sized Jar-coffins from Youngsan River by the Elemental Analysis (영산강유역 대형옹관의 태토 특성에 의한 분류)

  • Lee, Han-Hyoung;Hong, Jong-Ouk;Hwang, Jin-Ju;Park, Ji-Hee;Moon, Eun-Jung;Kim, Soo-Kyung;Chung, Yong-Sam;Moon, Jong-Hwa
    • 보존과학연구
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    • s.30
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    • pp.103-124
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    • 2009
  • Major and trace elements and cross section textures of the large-sized jar-coffins excavated in the Young San river area have been analyzed for categorization according to geochemical characteristics of the raw materials. As results, we have found out that the jar-coffins of the Oryang-dong and Ungok-dong have very similar characteristics, and those of Songwol-dong and Jangdeung show distinguishable characteristics from the others. In addition, similar characteristics have been detected in some U-shape jar-coffins from several sites such as Oryang-dong, Ungok-dong, Sinchon-ri, Mansu-ri and Yeon-ri posess on trace elements and cross section texture. These results indicate that there was active physical migration although the detail route of the physical migration is unclear at current stage.

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A Study for Conservation for the Wooden Coffin - Artificial Deterioration Using Fenton's Reagent - (녹나무목관 보존처리에 관한 연구 - Fenton 산화를 이용한 생재의 인공열화 연구 -)

  • Yang, Suk-Ja;Yang, Seok-Jin;Jeong, Ah-Reum
    • 보존과학연구
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    • s.30
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    • pp.203-215
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    • 2009
  • In the conservation treatment of wood remains, polymers, treatment methods, and treatment period can be varied, depending on the percentage of moisture content and species of trees. Thus, in order to apply the appropriate conservation treatment, a lot of information from the wood remains are required. Despite the information from the wood remains, testing a part of the wood remains is necessary to get information about the polymers. When the wooden coffin made of camphor trees was excavated, it was cracked in the section of radiation, and there were hairlines cracks. Therefore, without any conservation treatment, it is impossible to restore it. This experiment is for the conservation treatment of the wooden coffin excavated from Songhyun-dong tombs No 7, Changnyeong. For this experiment, I used camphor trees from Jejudo. The purpose of this experiment is to asses the possibility of preliminary testing materials before the conservation treatment on the wooden coffin. After the camphor trees from Jejudo are artificially aged by Fenton's reagent, they are As a result of oxidation by Fenton, the degree of oxidation is high in proportion to the amount of peroxide and iron sulfate. Among several samples, the sample 'na' made the most similar result to the wooden coffin from Songhyun-dong. If I use this condition to make the sample in polymer tests, it is very helpful to find the most suitable polymer for the conservation treatment of wooden coffin. After the same species of trees are oxidized by Fenton and they become the similar condition, we are able to find suitable methods of conservation treatment. The suitable methods reduce the demage of the remains and make us to get more information. Thus, we are able to carry out conservation treatment more exactly.

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Therapeutic Effects of Extract of Uncariae Ramulis and Testudinis Plastrum on Cochlear Morphologic Change Induced by Salicylate Ototoxicity (귀판 합 조구등 추출액이 살리실산 나트륨으로 유발된 와우의 형태학적 변화에 미치는 영향)

  • Ha Mi-Kyung;Ku Young-Hui;Choi In-Hwa
    • The Journal of Korean Medicine
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    • v.25 no.3
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    • pp.160-168
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    • 2004
  • Background and Objectives: Tinnitus is on the increase due to the increase in the elderly population, industrial pollution and noise pollution. This symptom is especially marked in patients with a hearing problem and the relationship between cause, mechanism and treatment is poorly understood. The characteristics of tinnitus and other hearing problems are well brought out using an animal model with salicylate ototoxicity. Therapeutic effects of Uncariae Ramulis and Testudinis Plastrum were expected in tinnitus and hearing problems; therefore we experimented on an animal model with salicylate ototoxicity. Salicylate is one of the most commonly prescribed drugs, although it has been recognized that salicylate induces hearing loss and tinnitus reversibly. The purpose of this study was to find the therapeutic effects of this by the morphologic study using salicylate ototoxicity. Materials and Methods : Twelve healthy Sprague-Dawley rats were divided into three groups: normal, control and sample. The sample group was treated with the extract of Uncariae Ramulis and Testudinis Plastrum (1cc/100g, once a day for 6 days). Then, to induce the salicylate ototoxicity in the control and sample groups, rats were injected intraperitoneally with sodium salicylate (500mg/kg). We observed the morphologic changes in the cochlea of the rats every 2, 3, 4 and 5 hours after injection. Results : The outer hair cells showed marked changes. Vacuolization formed in the cuticular plate and the endoplasm of the control group. The endoplasm and the cuticular plates of the sample group after 2 hours were similar to the control group, but the cuticular plates of the sample group observed after 3, 4 and 5 hours were not similar. Conclusions : The results suggest that an extract of Uncariae Ramulis and Testudinis Plastrum has therapeutic effects on an animal model with salicylate ototoxicity.

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Inhibition Effects of Frankincense Oil on Skin Aging (II): Focussed on Histological Observation (프랑킨센스 오일의 피부노화 억제 효과 (II) - 조직학적 관찰을 중심으로 -)

  • Choi, Oi-Sook;Kwon, Mi-Hwa;Kong, Min-Kyu;Lee, Soon-Hee;Gang, Sung-Rye;Kim, Pil-Sun;Kim, Young-Chul
    • Environmental Analysis Health and Toxicology
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    • v.23 no.2
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    • pp.129-138
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    • 2008
  • The purpose of this study was to investigate the effects of frankincense oil in skin aging animal model. Skin aging was induced by both the irradiation of UVB and the application of squalene monohydroperoxide (Sq-OOH) to the back of experimental animals for 4 weeks. And at the same time experimental materials were applied topically. Six to seven weeks female SHR-1 hairless mice were divided into five groups including normal (N: saline), control (C: UVB+Sq-OOH+saline), vehicle control (VC: UVB+Sq-OOH+jojoba oil), positive control (PC: UVB+Sq-OOH+0.01% retinoic acid) and experimental (E: UVB+Sq-OOH+3% Frankincense oil) groups, five animals each group. Lipid lamella and lipid content in stratum corneum of the E group were almost intact with a regular arrangement which were similar to the N group. Collagen fibers in dermis of the E group were almost intact with a regular arrangement which were similar to the N group. Relatively much less number of mast cells and inflammatory cells were found in the E group compared to the C group. The activities of XO, SOD and CAT were no significant difference between the E and N groups. In conclusion, the application of frankincense oil to the skin aging animal model reduced both the generation of free radicals and the damage of skin tissues. Therefore, frankincense oil can be used practically for the prevention or improvement of skin aging in terms of health promotion and beauty for the people.

A Study on the Physical Properties and Subjective Evaluation of the PTT[Poly(trimethylene terephthalate)] Fabric (PTT[Poly(trimethylene terephthalate)] 직물(織物)의 물리적(物理的) 특성(特性)및 주관적(主觀的) 평가(評價)에 관(關)한 연구(硏究))

  • Seo, Hyo-Jeong;Kim, Jong-Jun;Jeon, Dong-Won
    • Journal of Fashion Business
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    • v.7 no.4
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    • pp.121-128
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    • 2003
  • A new textile material, poly(trimethylene terephthalate) polymer, has been introduced to the textile industry. The structure of PTT is similar to the PET, while the tensile deformation and subsequent recovery property is better than that of PET. In this study, the physical and mechanical properties of textile woven fabrics made of PTT, PET, and nylon 6 yarns as the filling yarn were determined using the Kawabata Evaluation System (KES), including tensile, bending, shearing, compression, and surface related parameters. On top of these measurements, the subjective ratings by evaluators were performed on the fabric samples. From the examination of the stress-strain behavior of the yarn specimens focused on the recovery mode, it was evident that the PTT specimen developed lower stress at 3% elongation. The subsequent recovery curve showed that the PTT has less stress-decay rate than the other specimens, implying that the recovery behavior of the PTT is recommendable for the end-uses including stretchable textile materials, sports wears, etc. The KES bending rigidity(B) value of the PTT sample fabric was lower than that of the PET sample fabric. Subjective evaluation of the fabric samples by the evaluators on the descriptive word pair "soft - not soft" showed similar tendency with the KES B determination of the fabric samples.