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CFRP strengthening of steel columns subjected to eccentric compression loading

  • Keykha, Amir Hamzeh
    • Steel and Composite Structures
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    • v.23 no.1
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    • pp.87-94
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    • 2017
  • Steel structures often require strengthening due to the increasing life loads, or repair caused by corrosion or fatigue cracking. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials used to strengthen steel structures. Most studies on strengthening steel structures have been carried out on steel beams and steel columns under centric compression load. No independent article, to the author's knowledge, has studied the effect of CFRP strengthening on steel columns under eccentric compression load, and it seems that there is a lack of understanding on behavior of CFRP strengthening on steel columns under eccentric compression load. However, this study explored the use of adhesively bonded CFRP flexible sheets on retrofitting square hollow section (SHS) steel columns under the eccentric compression load, using numerical investigations. Finite Element Method (FEM) was employed for modeling. To determine ultimate load of SHS steel columns, eight specimens with two types of section (Type A and B), strengthened using CFRP sheets, were analyzed under different coverage lengths, the number of layers, and the location of CFRP composites. Two specimens were analyzed without strengthening (control) to determine the increasing rate of the ultimate load in strengthened steel columns. ANSYS was used to analyze the SHS steel columns. The results showed that the CFRP composite had no similar effect on the slender and stocky SHS steel columns. The results also showed that the coverage length, the number of layers, and the location of CFRP composites were effective in increasing the ultimate load of the SHS steel columns.

The applicability of FRP material for tunnel support (터널보강재로서 FRP재료의 적용성 검토)

  • Choi, Yong-Ki;Kwon, Oh-Youb;Bae, Gyu-Jin;Cho, Mahn-Sup
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.3 no.1
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    • pp.11-19
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    • 2001
  • The purpose of this study is to improve the problems in Umbrella Arch Method, such as the oxidation, the difficulties in installation and cutting of the steel pipe. The applicability of the high strength FRP (Fiber-Reinforced-Plastic) materials composed of glass fiber as a substitute of steel pipe was investigated in this study. The results of this study show that FRP material is better than steel pipe in work performance and the durability of material except for its price. From the numerical analysis with various types of FRP, it was evaluated that the equiangular curve type is more efficient than the flat type developed abroad, and the supporting effect of FRP-grout mixture is similar to that of steel-grout mixture in results of bending strength test.

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Complementary Alternative Medicine Use Amongst Breast Cancer Patients in the Northern Region of Peninsular Malaysia

  • Knight, Aishah;Hwa, Yen Siew;Hashim, Hasnah
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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    • pp.3125-3130
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    • 2015
  • Background: Breast cancer is a common cancer affecting women in Malaysia and the use of complementary/alternative medicine (CAM) has been associated with delays in getting treatment. The aim of the study was to explore the use of CAM and the influencing factors in the Northern region of Peninsular Malaysia. Materials and Methods: This was a cross-sectional descriptive study on a convenience sample of 100 Malaysian breast cancer survivors. Findings: The reported use of CAM among the breast cancer survivors was lower than in other studies but the types of CAM used had a similar pattern with nutrition supplements/vitamins being the most common. The factors that positively influenced the use of complimentary/traditional therapy were income and getting information from television or radio. Survivors with access to internet/blogs appear to have lower odds of using complimentary/traditional therapy compared to the respondents who reported no such access. Conclusions: Information transmitted via television and radio appears to have a positive influence on CAM use by breast cancer patients compared to other information sources and it is important to ensure that such information is accurate and impartial.

Parotid Gland Tumours in Turkish Population: Analysis of 165 Patients

  • Derin, Serhan;Erdogan, Selvet;Almac, Ahmet;Ulubil, Arif;Iseri, Mete;Aydin, Omer;Keskin, I Gurkan;Oran, Abdulkadir;Kuru, Fatma Demir
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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    • pp.3539-3542
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    • 2015
  • Background: Retrospective data on 165 patients who presented with a parotid mass and underwent surgery in our clinics during 2000-2009 were examined. The obtained data (demographic data, surgical procedures, histopathological diagnoses) were compared to similar studies to make contributions to the literature. Materials and Methods: Patients were classified according to their histopathological diagnosis. Surgical procedures and patient follow-up were clarified. The results are presented as means and standard deviations. Results: Of the 165 masses, 134 (81.3%) were benign and 31 (18.7%) were malignant. Pleomorphic adenoma was the most common benign tumour (79 patients, 59%). Lymphoma and adenoid cystic carcinoma were equally common and were the most common malignant parotid gland tumours (both 6 patients, 19.3%). The most frequent surgical procedure was superficial parotidectomy (92 patients, 55.7%), and the most commonly encountered surgical complication was facial paralysis (12 patients, 7.2%). Conclusions: Our data are generally in line with the literature but lymphoma was more common than in most previous reports. Although the number of cases was low, the high incidence of parotid gland lymphoma was remarkable.

Trace Metals in Airborne Particulates Collected at Cheju Island, Korea (제주도 대기 분진 중 미량금속의 농도 특성)

  • 최만식;박은주
    • Journal of Korean Society for Atmospheric Environment
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    • v.15 no.6
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    • pp.727-738
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    • 1999
  • Total 76 aerosol samples were collected at Sungsan in Cheju Inland by high volume air sample for 1 year, from May 1995 to April 1996, and were analyzed for major elements(Na, Mg, Ca, Al, Fe) and trace elements(Mn, Co, Ni, Zn, Cd, Pb, U) by ICP/AES and ICP/MS. This study aims to determine the concentrations of trace metals and their seasonal variations in the atmosphere of Cheju Island, where is the remote area from pollution sources and also is the midway of transport of Asian continental materials into the western North Pacific. The concentrations of Na and Mg contributed by sea-salt aerosols were similar to those in the western part of Cheju island(Kosan) and in the western coast of Korea(Mallipo). They showed the highest value in summer and the lowest in spring and winter. Crustal metals(Al, Fe, Ca, Mn, Co, U) were 2~3 times lower than those of Mallipo. These metals showed the lowest values in summer and the highest in spring. Pollution-derived metals (Zn, Cd and Pb) were 2~4 times lower than those in Malipo. Some elemental ratios in aerosols grouped by three wind directions(north-northwest, east, and south-southwest) such as Fe/Al and Pb/Zn are presented as useful tracers indicating source areas, and their differentiation may be explained by geology and fuel types of source areas.

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MICROBIAL COLONIZATION AND DIGESTION OF FEED MATERIALS IN CATTLE AND BUFFALOES II. RICE STRAW AND PALM PRESS FIBRE

  • Abdullah, N.;Ho, Y.W.;Jalaludin, S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.5 no.2
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    • pp.329-335
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    • 1992
  • Degradation of rice straw was observed to be higher (p<0.01) in the buffaloes than in cattle. At 48 h, the dry matter (DM) loss of straw for buffaloes was 53.6 0.8% and that for cattle was 48.7 2.6%. Palm press fibre (PPF) was poorly degraded in the rumen of both animal species. A loss of about 21% DM was observed in both cattle and buffaloes after 48 h of incubation in the rumen. The pattern of bacterial and fungal colonization of straw and PPF seemed to be similar in both cattle and buffaloes. Microbial colonization was restricted by plant structures like the silica crystals in both straw and PPF. The predominant bacteria colonizing both straw and PPF fragments were the rods. Eroded zones and digestion pits were pronounced in straw fragments after 1 h of incubation. The PPF fragments appeared undegraded even after 6 h of incubation. Fungal colonization of straw was rapid and extensive in both cattle and buffaloes. The sporangia observed in straw were mainly spherical or oval in shape, but fusiform sporangia with acuminate tip were predominantly seen in PPF fragments.

Comparison of p16INK4a Immunocytochemistry with the HPV Polymerase Chain Reaction in Predicting High Grade Cervical Squamous Intraepithelial Lesions

  • Indarti, Junita;Fernando, Darrell
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.9
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    • pp.4989-4992
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    • 2013
  • Aim: To compare p16INK4a immunocytochemistry with the HPV polymerase chain reaction in predicting high grade cervical squamous intraepithelial lesions. Materials and Methods: This diagnostic case-control study was conducted from January 2010 until December 2010. We obtained 30 samples, classified according to the degree of cervical intraepithelial neoplasia (CIN): 11 samples for CIN 1, 9 samples for CIN 2, and 10 samples for CIN 3. HPV PCR, p16INK4a immunocytochemistry, and histopathological examination were performed on all samples. Statistical analysis was conducted using SPSS 20.0. Results: In predicting CIN 2-3, we found p16INK4a to have similar specificity and positive predictive value as HPV PCR (95%, 97.2% vs 96.7%), but better sensitivity (87.5% vs 72.5%) and negative predictive value (82.1% vs 67.6%). The most prevalent types of high-risk HPV in our study were HPV 33, 35, 58, 52, and 16. Conclusions: p16INK4a has better diagnostic values than HPV PCR and may be incorporated in the triage of ASCUS and LSIL to replace HPV PCR. Genotype distribution of HPV differs in each region, providing a challenge to develop HPV vaccines based on the epidemiology of HPV in that particular region.

A Study on the Sleeve Cap Ease of Leather Garment (피혁 의류의 Sleeve Cap Ease 분량에 관한 연구)

  • 최보람;서미아
    • The Research Journal of the Costume Culture
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    • v.9 no.1
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    • pp.33-43
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    • 2001
  • In this study, both kinds of materials, that is, leather and woolen fabrics, which have similar thickness, have been adopted. To determine proper length of ease, not only sleeve cap height but also sleeve width has been adjusted mainly based on 5cm length of the ease, which follows maximum sleeve cap height, and then different length of ease, for example, 4cm, 3cm, 2cm and 1cm of ease, have been made. As a result, eighteen kinds in total of sleeves have been made: In other words, each nine kinds of both leather and woolen fabrics have different ease lengths. In addition, each sleeve has been inspected visually and functionally. Following conclusion has been gotten based on outcome of the study: 1. Proper ease length for manufacture of leather garment is said to be 1∼2 cm. As a result, ease length with higher sleeve cap height shall be 1∼2cm, while the length with lower sleeve cap height shall be 1cm or less. 2. Wider sleeve width has better function. Considering relations with sleeve cap height, sleeve width shall exceed +4cm of bicep line. 3. to satisfy a variety of those conditions while manufacturing leather garment, sleeve cap height, which is used for the manufacture of full dress and street wear garment, To lessen the ease length, body A.H shall be relatively loose under the arms, or pad shall be supplemented on the shoulder, so that the difference had better be lessened to solve such problems.

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Luminescence Study of Eu3+ Ions Doped BaMoO4 Nanoparticles

  • Bharat, L. Krishna;Lee, Soo Hyun;Yu, Jae Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.415.2-415.2
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    • 2014
  • Cost-effective, robust devices for solid-state lighting industry that converts electricity to light revolutionize the current lighting industry. Phosphor materials used in these devices should be synthesized in a low-cost and effective method for use in WLEDs. In this presentation, the synthesis of Eu3+ ions doped BaMoO4 phosphor samples by a facile synthesis process for red component of WLEDs will be shown. The tetragonal phase of the host lattice was substantiated by the X-ray diffraction patterns. The morphological studies were carried out by using a field-emission scanning electron microscope and transmission electron microscope. These confirmed the formation of a shuttle like particles with perpendicular protrusions in the middle of the particle. The photoluminescence (PL) properties exhibited good emission with a high asymmetry ratio when excited with ultraviolet B wavelengths (~ 280-315 nm). The cathodoluminescence (CL) spectra showed similar results to the PL spectra, indicating the rich red emission. The results suggest that this phosphor is a good material as red region component in the development of tri-band UV excitation based WLEDs.

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Development of Design Support System to Optimize the Temporary Work (강교량 설치 가설공사의 최적화설계 지원시스템 개발)

  • Cho, Hun-Hee;Park, Jae-Woo;Cho, Moon-Young;Kim, Jung-Yeol
    • Korean Journal of Construction Engineering and Management
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    • v.6 no.6 s.28
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    • pp.115-123
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    • 2005
  • Design of steel $bridge^{\circ}AEs$ temporary works has conducted relying on the experiences of engineers based on the previous similar projects. Consequently, there have been arguments against over-design of temporary bents to be required at the actual construction sites, and unnecessary design changes have been issued at the construction stage. In this study, we have developed an optimum design support system for temporary works of the steel bridge construction through establishing the database for the materials to be needed for implementation of temporary works. We've also improved the accuracy and efficiency of the works through the design optimization for temporary works, and contributed to reduce design changes as well as to utilize the design informations at the construction stage.