• Title/Summary/Keyword: Critical length

Search Result 1,158, Processing Time 0.03 seconds

Buckling Analysis using Fictitious Axial Forces and Its Application to Cable-Stayed Bridges with HSB800 Steel (가상축력을 이용한 좌굴해석 및 HSB800 강재를 적용한 사장교에 대한 적용성 분석)

  • Choi, Dong Ho;Yoo, Hoon;Gwon, Sun Gil;Lim, Ji Hoon
    • Journal of Korean Society of Steel Construction
    • /
    • v.29 no.1
    • /
    • pp.13-24
    • /
    • 2017
  • System buckling analysis is usually used to determine the critical buckling load in the buckling design of cable-stayed bridges. However, system buckling analysis may yield unexpectedly large effective lengths of the members subjected to a relatively small axial force. This paper proposes a new method to determine reasonable effective lengths of girder and tower members in steel cable-stayed bridges using fictitious axial forces. An improved inelastic buckling analysis with modified tangent modulus is also presented. The effective lengths of members in example bridges calculated using the proposed method are compared with those obtained using the conventional buckling analysis method. The proposed method provides much more resonable effective lengths of the members. When girder and tower members are built with HSB800 steel instead of conventional steel, the effective lengths of the members under a small axial force slightly decreases in the inelastic buckling analysis without fictitious axial forces, while the proposed method that considers fictitious axial forces provides almost no changes in such lengths.

A LysM Domain-Containing Protein LtLysM1 Is Important for Vegetative Growth and Pathogenesis in Woody Plant Pathogen Lasiodiplodia theobromae

  • Harishchandra, Dulanjalee Lakmali;Zhang, Wei;Li, Xinghong;Chethana, Kandawatte Wedaralalage Thilini;Hyde, Kevin David;Brooks, Siraprapa;Yan, Jiye;Peng, Junbo
    • The Plant Pathology Journal
    • /
    • v.36 no.4
    • /
    • pp.323-334
    • /
    • 2020
  • Lysin motif (LysM) proteins are reported to be necessary for the virulence and immune response suppression in many herbaceous plant pathogens, while far less is documented in woody plant pathogens. In this study, we preliminarily characterized the molecular function of a LysM protein LtLysM1 in woody plant pathogen Lasiodiplodia theobromae. Transcriptional profiles revealed that LtLysM1 is highly expressed at infectious stages, especially at 36 and 48 hours post inoculation. Amino acid sequence analyses revealed that LtLysM1 was a putative glycoprotein with 10 predicted N-glycosylation sites and one LysM domain. Pathogenicity tests showed that overexpressed transformants of LtLysM1 displayed increased virulence on grapevine shoots in comparison with that of wild type CSS-01s, and RNAi transformants of LtLysM1 exhibited significantly decreased lesion length when compared with that of wild type CSS-01s. Moreover, LtLysM1 was confirmed to be a secreted protein by a yeast signal peptide trap assay. Transient expression in Nicotiana benthamiana together with protein immunoblotting confirmed that LtLysM1 was an N-glycosylated protein. In contrast to previously reported LysM protein Slp1 and OsCEBiP, LtLysM1 molecule did not interact with itself based on yeast two hybrid and co-immunoprecipitation assays. These results indicate that LtLysM1 is a secreted protein and functions as a critical virulence factor during the disease symptom development in woody plants.

Signal Level Analysis of a Camera System for Satellite Application

  • Kong, Jong-Pil;Kim, Bo-Gwan
    • Proceedings of the KSRS Conference
    • /
    • 2008.10a
    • /
    • pp.220-223
    • /
    • 2008
  • A camera system for the satellite application performs the mission of observation by measuring radiated light energy from the target on the earth. As a development stage of the system, the signal level analysis by estimating the number of electron collected in a pixel of an applied CCD is a basic tool for the performance analysis like SNR as well as the data path design of focal plane electronic. In this paper, two methods are presented for the calculation of the number of electrons for signal level analysis. One method is a quantitative assessment based on the CCD characteristics and design parameters of optical module of the system itself in which optical module works for concentrating the light energy onto the focal plane where CCD is located to convert light energy into electrical signal. The other method compares the design\ parameters of the system such as quantum efficiency, focal length and the aperture size of the optics in comparison with existing camera system in orbit. By this way, relative count of electrons to the existing camera system is estimated. The number of electrons, as signal level of the camera system, calculated by described methods is used to design input circuits of AD converter for interfacing the image signal coming from the CCD module in the focal plane electronics. This number is also used for the analysis of the signal level of the CCD output which is critical parameter to design data path between CCD and A/D converter. The FPE(Focal Plane Electronics) designer should decide whether the dividing-circuit is necessary or not between them from the analysis. If it is necessary, the optimized dividing factor of the level should be implemented. This paper describes the analysis of the electron count of a camera system for a satellite application and then of the signal level for the interface design between CCD and A/D converter using two methods. One is a quantitative assessment based on the design parameters of the camera system, the other method compares the design parameters in comparison with those of the existing camera system in orbit for relative counting of the electrons and the signal level estimation. Chapter 2 describes the radiometry of the camera system of a satellite application to show equations for electron counting, Chapter 3 describes a camera system briefly to explain the data flow of imagery information from CCD and Chapter 4 explains the two methods for the analysis of the number of electrons and the signal level. Then conclusion is made in chapter 5.

  • PDF

Literature Review Nursing Intervention for Developmental Support on Preterm Infants (미숙아의 발달지지를 위한 간호중재에 관한 문헌연구)

  • Kim, Tae-Im;Sim, Mi-Kyung
    • Korean Parent-Child Health Journal
    • /
    • v.4 no.1
    • /
    • pp.35-55
    • /
    • 2001
  • Recently attention has been focused on the effects of early intervention, or its lack, on both normal and preterm infants. Particularly numerous studies suggest that premature infants are not necessarily understimulated but instead are subjected to inappropriate stimulation. Developmental support and sensory stimulation have become clinical opportunities in which nursing practice can impact on the neurobehavioral outcome of premature infants. Developmental care has been widely accepted and implemented in neonatal intensive care units across the country. Increasingly, attention and concern in caring for low-birth-weight infants and premature infants has led clinicians in the field to explore the effects of a complex of interventions designed to create and maintain a developmentally supportive environment; to provide age-appropriate sensory input; and to protect the infant from inappropriate, excessive and stressful stimulation. The components of developmental care include modifications of the macro-environment to reduce NICU light and sound levels, care clustering, nonnutritive sucking, and containment strategies, such as flexed positioning or swaddling. Sensory stimulation of the premature infants is presented to standardize the modification of a developmental intervention based on physiologic and behavioral cues. The most appropriate type of stimuli are those that are sensitive to infant cues. Evaluation of infant physiological and behavioral responds to specific intervention stimuli may help to identify more appropriate interventions based on infants' cues. A critical question confronting the clinician is that of determining when the evidence supporting a change in practice is sufficient to justify making that change. There are acknowledged limitations in the current studies. Many of the studies examined had small sample sizes; used nonprobability sampling; and used a phase lag design, which introduces the possibility of threats to internal validity and limits the generalizability of the results. Although many issues regarding the effects of developmental interventions remain unresolved, the available research base documents significant benefits of developmental care for LBW infants in consistent outcomes, without significant adverse effects. Particularly, although the individual studies vary somewhat in the definition of specific outcomes measured, instrumentation used, time and method of data collection, and preparaion of the care providers, in all studies, infants receiving the full protocol of individualized developmentally supportive care had improvements in some aspect of four areas of infant functioning: level of respiratory or oxygen support, the establishment of oral feeding; length of hospital stay, and infant behavioral regulation. In summary, based on the available literature, individualized developmental intervention should be incorporated into standard practice in neonatal intensive care. And this implementation needs to be coupled with ongoing research to evaluate the impact of an individualized developmental care programs on the short- and long-tenn health outcomes of LBW infants.

  • PDF

Degenerative Changes of Myocytes Induced by Restriction of Flight in Doves (비행운동 제한에 따른 비둘기 심근세포의 퇴행성 변화)

  • 문혜정;이용덕;박원학
    • Biomedical Science Letters
    • /
    • v.6 no.4
    • /
    • pp.269-279
    • /
    • 2000
  • This present study was investigated to elucidate degenerative changes according to the change of habitual environment on the myocytes of doves by restricting them from flight that is instinct behavior of this animal and strong exercise. To restrict doves from flight, they were confined in the cage (1 $m^3$) for 2 months. After this period, the myocardium of the experimental group was compared to that of wild doves in the ultrastructural and cytochemical ways. In addition, stereological changes were also examined. The results were as followings: 1. The body weight of the confined experimental groups was higher than that of the wild doves, but the ratios of the pectoral muscle/body weight (p<0.05) and the heart/body weight were lower. 2. At the ultrastructural level, the myocardium of confined doves appeared as wavy fibers in the smaller area than in the myocardium of wild doves. Also, the length of sarcomeres was longer in the confined doves. The number of sarcoplasmic reticulum and capillary was smaller in the myocardium of confined doves. 3. Cytochemical examinations showed that the activities of cytochrome oxidase were lowered in the confined doves. 4. Stereological analysis revealed that the density of myofibrils was greater in the confined doves. In contrast the volume density of sarcoplasmic reticulum (p<0.05) and the surface density of mitochondrial inner membrane (p<0.05) was lower in the confined doves, while the numerical density of mitochondrial inner membrane was higher (p<0.05). These results suggest that even the short period of restricted exercise can induce negative effects on the functions of myocytes of doves that are adapted for the strong exercise such as flight. Therefore, the maintenance of prolonged exercise seems to be one of the important factors that are critical to retain the functions of myocardium.

  • PDF

Methane Production and T-RFLP Patterns of Methanogenic Bacteria Dependent on Agricultural Methods (농법에 따른 메탄생성과 메탄생성 세균의 T-RFLP 패턴)

  • Kim, Hun-Soo;Cho, Ju-Sik;Park, Kyeong-Ryang
    • Korean Journal of Microbiology
    • /
    • v.45 no.1
    • /
    • pp.17-25
    • /
    • 2009
  • We studied soil components, methane production, the number of methanogens, and T-RFLP patterns dependent on agricultural methods with the change of seasons. There is no regular increase or decrease tendency of the most soil components followed by sampling period. And the water content in soil was higher in October than May. Also a lot of methanogens existed in soil, and acetotrophs were relatively of smaller number than hydogenotrophs and formate utilizing methanogens using MPN (most probable number) enumeration. In the experiment using the formate, it was used from the first week, and only a minute amount was detecte after four weeks. However in the acetate, it was increased until the third week, and after that was consumed. And there was higher methane production for all soil samples which administered with the hydrogen spike. The activity of methanogens was higher in the organic and low-agrichemical agricultural method samples, and the organic agricultural method had high methanogen activity among the other samples. A result of T-RFLP pattern of mcrA gene digested with Sau96I, methanogen community have a little relation with agricultural methods and seasons. This results also agreed to no critical difference the soil components dependent on agricultural methods, but some analytical data have a positive relationship with a agricultural methods. Therefor we could concluded that the comparison study of community for soil bacteria sufficiently could be useful for the microbiological indicator.

On the Seasonal Migration of Arzentine Hake, Merluccius hubbsi Marini (알젠틴 대구의 계절적 회유에 관하여)

  • CHUNG Sang-Chul;TANAKA Syoiti
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.18 no.6
    • /
    • pp.571-580
    • /
    • 1985
  • Based on the data collected by R/V "Shinkai Maru" of the Japan Marine Fishery Resources Research Center during the period from April 1978 to April 1979, seasonal migration of Merluccius hubbsi was studied using the catch per fishing effort (tons/30 min. haul) and gonad maturity index (gonad weight /body weight X $10^3$). Merlurccius hubbsi are found in the area between $36^{\circ}S\;and\;54^{\circ}S$ along the coast of Arzentine and are abundant especially above the 100 fathoms in northern offshore of $48^{\circ}S$. It was observed that critical maturity body lengths (spawning minimum body length) in terms of gonad maturity index are 40 cm and 30cm in female and male respectively, while spawning seasons are from December to January and from November to December for female and male respectively. It was assumed that while the group which distrbutes in the north ($36^{\circ}S{\sim}39^{\circ}S$) in spring moves down south to $42^{\circ}{\sim}46^{\circ}S$ for spawning in summer (from December to January), the group which does not move or a part of this group which comes back to the north spawn in the area north of $42^{\circ}S$ throughout the long period except winter time (from July to August). Southern group as well might move north and spawn after mixing together with northern group at $42^{\circ}{\sim}46^{\circ}S$ area around the period of December to January,

  • PDF

Test on the Structural Performance of the TOX Deck plate - Evaluation of Structural Safety during Construction Stage - (무용접 압접 데크플레이트의 구조성능에 관한 실험 - 시공단계에서의 구조안전성 평가 -)

  • Oh, Sang Hoon;Kim, Young Ju;Yoon, Myung Ho
    • Journal of Korean Society of Steel Construction
    • /
    • v.20 no.6
    • /
    • pp.701-709
    • /
    • 2008
  • Owing to the decreased work term and the convenience of construction work in Korea, the steel deck plate system has been widely used in the construction field. Most of all, due to its good stiffness and economic consideration, the steel-wire-integrated deck plate system (or truss deck plate system) has become very popular in recent years. But although it has many advantages, the truss deck plate system has a critical defect: it gets rusty in the welding joints between the lattice steel wire and the deck plate, resulting in the cracking of such welding joints and water leakage. To address these problems, a new type of truss deck plate system, which need not be welded and does not rust, was proposed herein: the TOX deck plate system. In this study, tests were conducted on 15 specimens to evaluate the structural safety of the proposed deck plate system during the construction stage. The test parameters were as follows: the depth of the slab the length of the span the diameters of the top, bottom, and lattice steel wire and the material properties of the zinc-coated steel sheets. The test results show that the TOX deck plate system can guarantee structural safety owing to its deflection and strength.

Development of Gate Choice Model of Subway Station (지하철 역사에서의 출구선택 모형 개발)

  • Park, Ji-Hun;Lee, Seung-Jae;Kim, Ju-Yeong
    • Journal of Korean Society of Transportation
    • /
    • v.28 no.1
    • /
    • pp.15-24
    • /
    • 2010
  • Until now, the location and the size of gate are designed by only experience and intuitive use judgement. However there are no studies that investigated how many people will be using each subway gate depending on the location of gates. Therefore, the purpose of this study is to develop a gate choice model of subway station. The most critical element of a gate choice in subway station is the location of pedestrian's destinations. In this study, the development of the regression model is constructed from data of land use characteristic of station vicinity and the number of bus route and the space structure of station vicinity(Depth concept by Space Syntax analysis and total road length of station vicinity) by using the real data of 30 subway station in Seoul. This study found that subway pedestrian flow are mainly determined by three factors; the total floor space of commercial buildings, Total Depth(space structure index of station vicinity), and the number of bus route. The verification of a proposed model is done by using the real gate pedestrian data of two subway station in Seoul; Gang-nam and Yang-jae. The additional study of how to define the gate impact area is analysed. Therefore, this study will provide the theoretical bases in decision of gate location and size when a new subway station is opened in future.

Behavior of Hybrid Stud under Compressive Load (복합스터드의 압축 좌굴 거동)

  • Lee, Sang Sup;Bae, Kyu Woong
    • Journal of Korean Society of Steel Construction
    • /
    • v.16 no.5 s.72
    • /
    • pp.609-619
    • /
    • 2004
  • An investigation was conducted on the activities around Europe in order to solve the problem of the thermal bridging of steel studs, which had caused a significant disadvantage. This study included the following: diminishing the contact area between the studs and the sheathing, lengthening the heat transfer route, replacing the steel web with a less conductive material, and placing foam insulation in locations where the thermal shorts are most critical. Although energy efficiency is usually the focus of such foreign cases because their stud application is mostly limited to low-rise residential buildings, both structural and thermal performance are taken into consideration in this study because these target middle-story buildings. A hybrid stud composed of steel and polymer was also developed. This hybrid stud, which is 150 SL in size, is made of a galvanized steel sheet (SGC58) and a glass fiber reinforced polymer (GFRP) withepoxy bonding. A total of 32 specimens were manufactured. Its parameters comprise two types of connection detail,s: the thickness of steel (1.0mm and 1.2mm) and of the GFRP (4mm-4ply and 6mm-6ply), and the ratio of the length to the depth (L/D = 3, 6, 9, 12). Steel stud specimens with the same conditions were compared to the hybrid stud. The test revealed that in the case of the steel specimen with a thickness of 1.0mm, the maximum load of hybrid studs increased an average of 1.62 times comparedto that of the steel stud. In the case of the steel specimen with a thickness of 1.2mm, on the other hand, the average increase was 1.46times. All specimens showed full composite action until the collapse.