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Experimental Investigation for Flexural Stiffness of Paperboard-stacked Structure

  • Lee, Myung-Hoon;Park, Jong-Min
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.7 no.1
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    • pp.9-15
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    • 2001
  • Top-to-bottom compression strength of corrugated fiberboard boxes is partly dependent on the load-carrying ability of the central panel areas. The ability of these central areas to resist bending under load will increase the stacking strength of the box. The difference of box compression strengths, among boxes which are made with identical dimensions and fabricated with same components but different flute sizes, is primarily due to difference of the flexural stiffness of the box panels. Top-to-bottom compression strength of a box is accurately predicted by flexural stiffness measurements and the edge crush test of the combined boards. This study was carried out to analyze the flexural stiffness, maximum bending force and maximum deflection for various corrugated fiberboards by experimental investigation. There were significant differences between the machine direction (MD) and the cross-machine direction (CD) of corrugated fiberboards tested. It was about 50% in SW and DW, and $62%{\sim}74%$ in dual-medium corrugated fiberboards(e.g. DM, DMA and DMB), respectively. There were no significant differences of maximum deflection in machine direction among the tested fiberboards but, in cross direction, DM showed the highest value and followed by SW, DMA, DMB and DW in order. For the corrugated fiberboards tested, flexural stiffness in machine direction is about $29%{\sim}48%$ larger than cross direction, and difference of flexural stiffness between the two direction is the lowest in DMA and DMB.

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DEAD/DExH-Box RNA Helicases in Selected Human Parasites

  • Marchat, Laurence A.;Arzola-Rodriguez, Silvia I.;Cruz, Olga Hernandez-de la;Lopez-Rosas, Itzel;Lopez-Camarillo, Cesar
    • Parasites, Hosts and Diseases
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    • v.53 no.5
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    • pp.583-595
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    • 2015
  • DEAD/DExH-box RNA helicases catalyze the folding and remodeling of RNA molecules in prokaryotic and eukaryotic cells, as well as in many viruses. They are characterized by the presence of the helicase domain with conserved motifs that are essential for ATP binding and hydrolysis, RNA interaction, and unwinding activities. Large families of DEAD/DExH-box proteins have been described in different organisms, and their role in all molecular processes involving RNA, from transcriptional regulation to mRNA decay, have been described. This review aims to summarize the current knowledge about DEAD/DExH-box proteins in selected protozoan and nematode parasites of medical importance worldwide, such as Plasmodium falciparum, Leishmania spp., Trypanosoma spp., Giardia lamblia, Entamoeba histolytica, and Brugia malayi. We discuss the functional characterization of several proteins in an attempt to understand better the molecular mechanisms involving RNA in these pathogens. The current data also highlight that DEAD/DExH-box RNA helicases might represent feasible drug targets due to their vital role in parasite growth and development.

Surface Inspection Algorighm using Oriented Bounding Box (회전 윤곽 상자를 이용한 표면 검사 알고리즘)

  • Hwang, Myun Joong;Chung, Seong Youb
    • Journal of Institute of Convergence Technology
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    • v.6 no.1
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    • pp.23-26
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    • 2016
  • DC motor shafts have several defects such as double cut, deep scratch on surface, and defects in diameter and length. The deep scratches are due to collision among the other shafts. So the scratches are long and thin but their orientations are random. If the smallest enclosing box, i.e. oriented bounding box for a detective point group is found, then the size of the corresponding defect can be modeled as its diagonal length. This paper proposes an suface inspection algorithm for the DC motor shaft using the oriented bounding box. To evaluate the proposed algorithm, a test bed is made with a line scan CCD camera (4096 pixels/line) and two rollers mechanism to rotate the shaft. The experimental result on a pre-processed image with contrast streching algorithm, shows that the proposed algorithm sucessfully finds 150 surface defects and its computation time (0.291 msec) is enough fast for the requirement (4 seconds).

An Experimental Study on the Condensation Characteristics of Sea Water in the Tilted Box with Solar Radiation (태양열을 받는 경사진 육면체 내 해수의 응축특성에 관한 실험적 연구)

  • Kim, Beom-Han;Kim, Byung-Chul
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.27-33
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    • 2011
  • To find effective way of the production of distilled water for drought and flood with solar radiation, three boxes were made same base each 1000mm ${\times} $1000mm and tops are 45 degree. Individual boxes contained the sea water, rain water and surface water were placed at the same location and same time. Condensation of each box has been compared. On clear day production of distilled water in the box with sea water was 36% and 32% less than boxes with rain water and surface water. The maximum condensation reached when the temperature of the top and bottom parts are equal. As concentration of sea water increased production of distilled water was decreased. In the box with sea water, the surface temperature was lower than 3cm below the surface. Optimum collector area for producing distilled water 2000ml of these three boxes were $3.75m^2$

Steel Box Girder Bridge Models of Light Rail Transit with HR Plate (HR Plate의 경량전철 강박스거더교 적용모델)

  • Lee, Seong-Haeng;Yim, Chae-Sun;Hwang, Nak-Yuen;Jung, Kyoung-Sup
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.554-562
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    • 2007
  • To increase the demand of HR Plate with thickness up to 22mm, it is necessary that HR Plate is applicable to full member in steel bridge including main girder. In this study, availabilities of the narrow steel box girder of light railway transit with HR Plate width as a main member are discussed. Computational analysis is performed in 15 bridge models of light railway transit with beam element and plate element. As an analysis results, three models in tight railway transit are presented. In conclusion, it is validated that HR Plate can be applying to narrow steel box girder in the light railway transit.

Shear-lag behavior of prestressed concrete box-girder bridges during balanced cantilever construction

  • Zhong, Xingu;Zhang, Tianyu;Shu, Xiaojuan;Xu, Hongliang
    • Advances in concrete construction
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    • v.5 no.5
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    • pp.469-479
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    • 2017
  • Balanced cantilever construction is extensively used in the construction of prestressed concrete (PSC) box-girder bridges. Shear-lag effect is usually considered in finished bridges, while the cumulative shear-lag effect in bridges during balanced cantilever construction is considered only rarely. In this paper, based on the balanced cantilever construction sequences of large-span PSC box-girder bridges, the difference method is employed to analyze the cumulative shear-lag effect of box girders with varying depth under the concrete segments' own weight. During cantilever construction, no negative shear-lag effect is generated, and the cumulative shear-lag effect under the balanced construction procedure is greater than the instantaneous shear-lag effect in which the full dead weight is applied to the entire cantilever. Three cross-sections of Jianjiang Bridge were chosen for the experimental observation of shear-lag effect, and the experimental results are in keeping with the theoretical results of cumulative shear-lag effect. The research indicates that only calculating the instantaneous shear-lag effect is not sufficiently safe for practical engineering purposes.

An Efficient Implementation of AES Encryption Algorithm for CCTV Image Security (CCTV 영상보안 위한 AES 암호 알고리듬의 효율적인 구현)

  • Kang, Min-Sup
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.21 no.2
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    • pp.1-6
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    • 2021
  • In this paper, an efficient implementation of AES encryption algorithm is presented for CCTV image security using C# language. In this approach, an efficient S-Box is first designed for reducing the computation time which is required in each round process of AES algorithm, and then an CCTV image security system is implemented on the basis of this algorithm on a composite field GF(((22)2)2). In addition, the shared S-Box structure is designed for realizing the minimized memory space, which is used in each round transformation and key scheduling processes. Through performance evaluation, it was confirmed that the proposed method is more efficient than the existing method. The proposed CCTV system in C# language using Visual studio 2010.

Computation of design forces and deflection in skew-curved box-girder bridges

  • Agarwal, Preeti;Pal, Priyaranjan;Mehta, Pradeep Kumar
    • Structural Engineering and Mechanics
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    • v.78 no.3
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    • pp.255-267
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    • 2021
  • The analysis of simply supported single-cell skew-curved reinforced concrete (RC) box-girder bridges is carried out using a finite element based CsiBridge software. The behaviour of skew-curved box-girder bridges can not be anticipated simply by superimposing the individual effects of skewness and curvature, so it becomes important to examine the behaviour of such bridges considering the combined effects of skewness and curvature. A comprehensive parametric study is performed wherein the combined influence of the skew and curve angles is considered to determine the maximum bending moment, maximum shear force, maximum torsional moment and maximum vertical deflection of the bridge girders. The skew angle is varied from 0° to 60° at an interval of 10°, and the curve angle is varied from 0° to 60° at an interval of 12°. The scantly available literature on such bridges focuses mainly on the analysis of skew-curved bridges under dead and point loads. But, the effects of actual loadings may be different, thus, it is considered in the present study. It is found that the performance of these bridges having more curvature can be improved by introducing the skewness. Finally, several equations are deduced in the non-dimensional form for estimating the forces and deflection in the girders of simply supported skew-curved RC box-girder bridges, based upon the results of the straight one. The developed equations may be helpful to the designers in proportioning, analysing, and designing such bridges, as the correlation coefficient is about 0.99.

Flutter performance of box girders with different wind fairings at large angles of attack

  • Tang, Haojun;Zhang, Hang;Mo, Wei;Li, Yongle
    • Wind and Structures
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    • v.32 no.5
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    • pp.509-520
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    • 2021
  • The streamlined box is a common type of girders for long-span suspension bridges. Spanning deep canyons, long-span bridges are frequently attacked by strong winds with large angles of attack. In this situation, the flow field around the streamlined box changes significantly, leading to reduction of the flutter performance. The wind fairings have different effects on the flutter performance. Therefore, this study examines the flutter performance of box girders with different wind fairings at large angles of attack. Computational fluid dynamics (CFD) simulations were carried out to extract the flutter derivatives, and the critical flutter state of a long-span bridge was determined. Further comparisons of the wind fairings were investigated by a rapid method which is related to the input energy by the aerodynamic force. The results show that a reasonable type of wind fairings could improve the flutter performance of long-span bridges at large angles of attack. For the torsional flutter instability, the wind fairings weaken the adverse effect of the vortex attaching to the girder, and a sharper one could achieve a better result. According to the input energies on the girder with different wind fairings, the symmetrical wind fairings are more beneficial to the flutter performance

Thermal Analysis of a Cold Box for a Hydrogen Liquefaction Pilot Plant with 0.5 TPD Capacity (0.5 TPD 급 수소액화 파일럿 플랜트의 콜드박스 열해석)

  • KIM, HYOBONG;HONG, YONG-JU;YEOM, HANKIL;PARK, JIHO;KO, JUNSEOK;PARK, SEONG-JE;IN, SEHWAN
    • Journal of Hydrogen and New Energy
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    • v.31 no.6
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    • pp.571-577
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    • 2020
  • Thermal analysis was performed for a cold box of a hydrogen liquefaction pilot plant with 0.5 ton/day capacity. The pilot plant has adopted a hydrogen liquefaction process using two-stage helium Brayton cycle with precooling of liquid nitrogen. The cold box for hydrogen liquefaction has generally vacuum insulation but inevitable heat invasion by conduction and radiation exists. The heat loads were calculated for cold box internals according to multilayer insulation emissivity. Total heat load of 181.7 W is estimated for emissivity of 0.03 considered in field condition.