• Title/Summary/Keyword: F/A-18E/F

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Study on the Physical and Mechanical Properties of Particleboard and Oriented Strandboard Manufactured by Tulliptree (Liriodendron tulipifera L.) (백합나무를 이용하여 제조한 3층 파티클보드와 배향성 스트랜드보드(OSB)의 물성에 관한 연구)

  • Seo, Jun won;Gang, Gil woo;Jo, Gun hee;Park, Heon
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.1
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    • pp.67-72
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    • 2018
  • This study was conducted to investigate a potential of Yellow poplar (Liriodendron tulipifera L.) as a raw material for the manufacturing of particleboard (PB) and oriented strandboard (OSB). PB panels were prepared at the parameters of $0.7g/cm^3$ density, 15 mm thickness, three-layer, $E_1$ grade urea-formaldehyde (UF) resin, emulsion wax, and hardener. OSB panels were manufactured with a density of $0.65g/cm^3$, thickness of 10 mm, and $E_1$ grade of UF resin. Particle size of the face layer of PB was 20~80 mesh with 7~9% moisture content (MC), while that of core-layer was 3~20 mesh with 3~5% MC, which was similar to the production condition of commercial PB. As a result, the manufactured PB panels with 15.8 mm thickness, $0.7g/cm^3$ density, and 5.8% MC satisfied the requirement of bending strength of 15 type PB of Korean Industrial Standard (KS F 3104). Both internal bonding (IB) strength and surface screw withdrawal resistance also satisfied the requirement of 18 type PB of the standard. But, the edge screw withdrawal resistance satisfied the requirement of 15 type PB of the standard. These differences in properties could be due to the slenderness ratio of raw particles. In case of OSB panels with 10.7 mm thickness, $0.68g/cm^3$ density, and 5.8% MC satisfied all the requirements of bending strength, screw withdrawal resistance, and IB strength of 18 type PB of the standard. These results suggest that Yellow poplar wood has a good potential as a raw material for the production of PB and OSB.

Interaction-based Collaborative Recommendation: A Personalized Learning Environment (PLE) Perspective

  • Ali, Syed Mubarak;Ghani, Imran;Latiff, Muhammad Shafie Abd
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.1
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    • pp.446-465
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    • 2015
  • In this modern era of technology and information, e-learning approach has become an integral part of teaching and learning using modern technologies. There are different variations or classification of e-learning approaches. One of notable approaches is Personal Learning Environment (PLE). In a PLE system, the contents are presented to the user in a personalized manner (according to the user's needs and wants). The problem arises when a new user enters the system, and due to the lack of information about the new user's needs and wants, the system fails to recommend him/her the personalized e-learning contents accurately. This phenomenon is known as cold-start problem. In order to address this issue, existing researches propose different approaches for recommendation such as preference profile, user ratings and tagging recommendations. In this research paper, the implementation of a novel interaction-based approach is presented. The interaction-based approach improves the recommendation accuracy for the new-user cold-start problem by integrating preferences profile and tagging recommendation and utilizing the interaction among users and system. This research work takes leverage of the interaction of a new user with the PLE system and generates recommendation for the new user, both implicitly and explicitly, thus solving new-user cold-start problem. The result shows the improvement of 31.57% in Precision, 18.29% in Recall and 8.8% in F1-measure.

Direct-fed Enterococcus faecium plus bacteriophages as substitutes for pharmacological zinc oxide in weanling pigs: effects on diarrheal score and growth

  • Oh, Sang-Hyon;Jang, Jae-Cheol;Lee, Chul Young;Han, Jeong Hee;Park, Byung-Chul
    • Animal Bioscience
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    • v.35 no.11
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    • pp.1752-1759
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    • 2022
  • Objective: Effects of direct-fed Enterococcus faecium plus bacteriophages (EF-BP) were investigated as potential substitutes for pharmacological ZnO for weanling pigs. Methods: Dietary treatments were supplementations to a basal diet with none (NC), 3,000-ppm ZnO (PC), 1×1010 colony-forming units of E. faecium plus 1×108 plaque-forming units (PFU) of anti-Salmonella typhimurium bacteriophages (ST) or 1×106 PFU of each of anti-enterotoxigenic Escherichia coli K88 (F4)-, K99 (F5)-, and F18-type bacteriophages (EC) per kg diet. In Exp 1, twenty-eight 21-day-old crossbred weanling pigs were individually fed one of the experimental diets for 14 days and euthanized for histological examination on intestinal mucosal morphology. In Exp 2, 128 crossbred weanling pigs aged 24 days were group-fed the same experimental diets in 16 pens of 8 piglets on a farm with a high incidence of post-weaning diarrhea. Results: None of the diarrheal score or fecal consistency score (FCS), average daily gain (ADG), gain: feed ratio, structural variables of the intestinal villus, and goblet cell density, differed between the EF-BP (ST+EC) and NC groups, between EF-BP and PC, or between ST and EC, with the exception of greater gain: feed for EF-BP than for PC (p<0.05) during days 7 to 14 (Exp 1). In Exp 2, ADG was less for EF-BP vs PC during days 0 to 7 and greater for EF-BP vs NC during days 7 to 14. FCS peaked on day 7 and declined by day 14. Moreover, FCS was less for EF-BP vs NC, did not differ between EF-BP and PC, and tended to be greater for ST vs EC (p = 0.099). Collectively, EF-BP was comparable to or slightly less effective than PC in alleviating diarrhea and growth check of the weanling pigs, with ST almost as effective as PC, when they were group-fed. Conclusion: The E. faecium-bacteriophage recipe, especially E. faecium-anti-S. typhimurium, is promising as a potential substitute for pharmacological ZnO.

A Study of Indonesian Online Marketplace: Information Processing Theory Paradigm

  • TEOFILUS, Teofilus;SUTRISNO, Timotius F.C.W.;HONGDIYANTO, Charly;WANANDA, Veronica
    • Journal of Distribution Science
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    • v.18 no.8
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    • pp.75-87
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    • 2020
  • Purpose: This study uses the protection motivation theory and information processing theory to discuss the high number of fraud phenomenon in Indonesia which causes worries to the internet users. The second problem is the large amount of information transparency in e-commerce which actually hinders the users in making decisions so it causes a negative behavior pattern, namely discontinue usage intention. Design/methodology: Therefore, this research hopes to provide insight to the online or e-commerce business community, especially for Tokopedia, to develop its business from understanding the factors influencing consumer attitude when shopping online. The sample are students from Universitas Indonesia, Institut Teknologi Bandung, Institut Pertanian Bogor, Universitas Gadjah Mada and Institut Teknologi Surabaya, with total 900 respondents. Result: The results of this research indicate that ubiquitous connectivity (UC) variable significantly affects variables such as the privacy concern (PC), information transparency (IT) and information overload (IO). PC and IO variables also significantly affect Discontinue Usage Intention (DUI). Conclusion: This study gives a new perspective that despite the phenomenon, the millennial generation especially are not entirely concerned about the privacy concern, however, this study clearly shows that the privacy issue in the digital word continues to be something that needs to be cared for.

A Study on the Properties of Electric Arc-Furnace Steelmaking Dusts for Stabilization Processing (안정화 처리를 위한 전기로 제강분진의 물성)

  • 현종영;조동성
    • Resources Recycling
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    • v.7 no.5
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    • pp.13-18
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    • 1998
  • This study was carried out to understand the properties of the E.A.F. steel-making dusts for stabilization processing. The properties are related to mincral composition, shape, particle size, magnetism, density, porosity and leaching characteristic. the dust particles, the size of which ranges from sub-micron to tens-micron, were mainly spherical like balls that were agglomerated each other: the large particles were generally Fe-rich and the small particles were spherical like balls that were agglomerated each other: the large particles were franklinite (ZnFe$_{2}O_{4}$), magnetite (Fe$_{3}O_{4}$) and zincite (ZnO) by XRD analysis. When the dusts were sieved by a wet process, the particle fraction over 200 mesh had 1.5 wt.% with magnetite and quartz. The particles in the size range of 200-500 mesh consisted of magnetite, franklinite. The 82 wt.% of the steel-making dusts were occupied by the particles finer than 500 mesh and contained franklinite and zincite as main mineralogical compositions. When the dusts of around 78% porosity compressed under the load of approximately 1 KPa, the porosity decreased to 68% and to 535 under around 13 KPa. When the E.A.F. dusts were leached according to the Korea standard leaching procedure on the waster, the heavy metals exceeding the leaching criteria were cadmium, lead and mercury.

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Complement Activation by Tobacco Infusion (담배가 가토(家兎) 보체(補體) 활성(活性)에 미치는 효과(效果))

  • Chung, Hyung-Ho;Kim, Doo-Hie;Chung, Tae-Ho
    • Journal of Preventive Medicine and Public Health
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    • v.18 no.1
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    • pp.91-97
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    • 1985
  • The capacity of tobacco infusions of Korean cigarettes to activate the complement pathway was investigated in vitro by hemolytic assay. Complement activity was studied using samples of normal rabbit serum incubated at $37^{\circ}C$ with tobacco infusions. In all mixtures containing tobacco infusion A, B, C, D, E, F, G, H and I at a concentration of 0.1 : 1, total hemolytic complement showed a progressive decrease of 55.92%, 48.62%, 42.89%, 49.12%, 42.26%, 52.26%, 71.96%, 60.90%, and 61.14% respectively, after 60min of incubation. This study suggests that all tobacco infusions of Korean cigarettes are activators of complement.

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Optimum Design of an Indoor Package Air-Conditioner's Flow Path by Taguchi Method (다구찌 방법에 의한 PAC 실내기 유로의 최적설계)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Journal of Power System Engineering
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    • v.18 no.1
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    • pp.32-37
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    • 2014
  • In this study, the optimum design process of an indoor package air-conditioner (PAC) was implemented by Taguchi method. The goal of this study is to obtain the best set condition of each control factor composing of an indoor PAC. The number of revolution of a double inlet sirocco fan installed in an indoor PAC was measured by the orthogonal array of $L_{18}(2^3{\times}3^4)$ and analysed by using the-smaller- the-better characteristic among the static characteristic analyses. As a result, the optimum condition of an indoor PAC was found as a set of when the cost of production, assembling and working conditions were considered. Moreover, the number of revolution of a double-inlet sirocco fan used for an optimum condition was reduced about 8.5% more than that of a standard condition for the target flowrate of $18.5m^3/min$.

The Crystallographic and Magnetic Properties of $Fe_{0.8}Co_{0.18}(BN_{0.02}$ Synthesized by Heat Treatment and Plastic Deformation ($Fe_{0.8}Co_{0.18}(BN_{0.02}$의 열처리 및 소성변형에 의한 결정구조와 자기적 성질)

  • 김정기;한경훈;이상문;정재윤;김예니;신경호
    • Journal of the Korean Magnetics Society
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    • v.10 no.5
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    • pp.225-231
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    • 2000
  • The crystallographic and magnetic properties of the sample F $e_{0.8}$ $Co_{0.18}$(BN)$_{0.02}$ synthesized by microwave arc-melting with the maximum power of 3.5 kW have been studied by the methods of an X-ray diffraction and the measurement of the magnetic hysteresis using the vibrating sample magnetometer at room temperature. The samples were prepared in a form of pellet pressed under the pressure of 9,000 N/c $m^2$, rolled coldly, and treated with the different temperatures. The X-ray diffraction pattern of pelleted sample shows that the crystal structure of the sample is bcc as same as that of Fe with a good uniformity. The X-ray diffraction pattern shows that a residual stress, which exists in the sample, is eliminated by final 90$0^{\circ}C$ annealing. As rolling rate and heat treatment temperature increases, the saturation magnetization and the remanence of the samples increase whereas the coercivity of the samples shows decrease. Also the saturation magnetization and the remanence of the samples were affected by rolling rate and rolling direction than heat treatment temperature, but the coercivity of the samples was affected by rolling rate and direction as well as heat treatment temperature. This means that a domain wall motion is easy due to elimination of a residual stress and an inclusion which exists in the sample by rolling and heat treatment and a local induced-magnetization easy axis was also formed to parallel to the rolling direction due to creation of the like-atom pairs across the slip plane by rolling......

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Analysis of Quantitative Trait Loci (QTLs) for Unsaturated Fatty Acid Contents in Soybean Seed Using Recombinant Inbred Lines (콩에서 microsatellite marker를 이용한 불포화지방산 함량의 양적형질 유전자좌의 분석)

  • Kim, Hyeun-Kyeung;Im, Moo-Hyeog;Choung, Myoung-Gun
    • Journal of Life Science
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    • v.18 no.12
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    • pp.1665-1670
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    • 2008
  • Soybean oil is an important source of vegetable oil for human food and nonfood applications and accounts for approximately 22% of the world's total edible oil production. Improvement of the quality and quantity of soybean seed oil constituents is one of the most important objectives in soybean breeding. The objective of this study was to identify quantitative trait loci (QTLs) that control oleic, linoleic, and linolenic acid contents in soybean. The 117 $F_{2:10}$ recombinant inbred lines (RIL) developed from a cross of 'Keunolkong' and 'Shinpaldalkong' were used. Narrow-sense heritability estimates based on a plot mean on seed weight, protein and oil content were 0.85, 0.82 and 0.81, respectively. Eight independent QTLs for oleic acid content were identified from linkage group (LG) A2, C1, D2, F, G, L, and O. Seven QTLs for linoleic acid content were located on LG D1b, E, H, I and L. Oil content was related with five QTLs located on LG C1, H, J, K, and L. Oleic, linoleic, and linolenic acid have two common QTLs on LG C1 and L. Thus, we identified major loci improving soybean oil quality.

Characteristic Behavior of High-Strength Concrete Columns under Simulated Seismic Loading

  • Hwang, Sun-Kyoung
    • International Journal of Concrete Structures and Materials
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    • v.18 no.2E
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    • pp.79-87
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    • 2006
  • The main objective of this research is to examine the behavior of high-strength concrete(HSC) columns. Eight test columns in one-third scale were tested under the conditions of cyclic lateral force and a constant axial load equal to 30% of the column axial load capacity. The $200{\times}200mm$ square columns were reinforced with eight DB bars constituting a longitudinal steel ratio of 2.54% of the column cross-sectional area. The main experimental parameters were volumetric ratio of transverse reinforcement(${\rho}_s$=1.58, 2.25 percent), tie configuration(Type H, Type C, Type D) and tie yield strength($f_{yh}$=548.8 and 779.1 MPa). It was found that the hysteretic behaviour and ultimate deformability of HSC columns were influenced by the amount and details of transverse reinforcement in the potential plastic hinge regions. Columns of transverse reinforcement in the amount 42 percent higher than that required by seismic provisions of ACI 318-02 showed ductile behavior. At 30% of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 548.8 MPa. Correlations between the calculated damage index and the damage progress are proposed.