• Title/Summary/Keyword: stiff system

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Soft-$golf^{TM}$ Shaft Kick Point and Stiffness due to the Difference in Performance Analysis (소프트 골프 샤프트의 킥 포인트와 강성의 차이에 따른 성능 분석)

  • Oh, H.Y.;Yu, M.;Kim, S.H.;Jang, J.H.;Kim, N.G.;Kim, D.W.
    • Journal of Biomedical Engineering Research
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    • v.31 no.3
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    • pp.227-233
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    • 2010
  • This study analyzed performance according to kick point and stiffness of Soft-$golf^{TM}$ shaft. This research team developed soft-$golf^{TM}$ as a new fusion sports with similar motions with golf and it can be learned safely for all age groups in 2002. The head of Soft-$golf^{TM}$ club is made of zinc alloy and has a mesh or a grid structure, and shaft uses carbon graphite to reduce the total weight of the club. To improve carry distance and to assure consistency of a ball during Soft-$golf^{TM}$ swing, this study manufactured shaft with various kick points (low, middle and high) and stiffness (stiff, regular, lady, morelady) and analyzed a swing motion with characteristics of each shaft presented in a dynamic condition such as a ball's speed, a head's torsion angle and a ball's deviation with ProAnalyst program through a high-speed camera taking pictures using a swing machine robot system(Robo-7). From all of the results, this study determined an appropriate shaft of Soft-$golf^{TM}$.

Human-Induced Vibrations in Buildings

  • Wesolowsky, Michael J.;Irwin, Peter A.;Galsworthy, Jon K.;Bell, Andrew K.
    • International Journal of High-Rise Buildings
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    • v.1 no.1
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    • pp.15-19
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    • 2012
  • Occupant footfalls are often the most critical source of floor vibration on upper floors of buildings. Floor motions can degrade the performance of imaging equipment, disrupt sensitive research equipment, and cause discomfort for the occupants. It is essential that low-vibration environments be provided for functionality of sensitive spaces on floors above grade. This requires a sufficiently stiff and massive floor structure that effectively resists the forces exerted from user traffic. Over the past 25 years, generic vibration limits have been developed, which provide frequency dependent sensitivities for wide classes of equipment, and are used extensively in lab design for healthcare and research facilities. The same basis for these curves can be used to quantify acceptable limits of vibration for human comfort, depending on the intended occupancy of the space. When available, manufacturer's vibration criteria for sensitive equipment are expressed in units of acceleration, velocity or displacement and can be specified as zero-to-peak, peak-to-peak, or root-mean-square (rms) with varying frequency ranges and resolutions. Several approaches to prediction of floor vibrations are currently applied in practice. Each method is traceable to fundamental structural dynamics, differing only in the level of complexity assumed for the system response, and the required information for use as model inputs. Three commonly used models are described, as well as key features they possess that make them attractive to use for various applications. A case study is presented of a tall building which has fitness areas on two of the upper floors. The analysis predicted that the motions experienced would be within the given criteria, but showed that if the floor had been more flexible, the potential exists for a locked-in resonance response which could have been felt over large portions of the building.

Self-differentiation of University Students and their Responses to Kinetic House-Tree-Person Drawings (대학생의 자아분화와 동적 집-나무-사람 그림 반응특성 연구)

  • 정윤정;최외선
    • Journal of Families and Better Life
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    • v.22 no.4
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    • pp.43-61
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    • 2004
  • The purpose of this study was to verify the usefulness of kinetic House- Tree- Person drawing as a diagnostic measure for the degree of self-differentiation, which is an essential part of college students' development. Participants for the study were four hundred thirty five(272 male and 163 female) university freshmen enrolled in 4-year colleges located in Pusan. The Participants completed a scale of self-differentiation and a Kinetic House- Tree-Person drawings test. The evaluation system for kinetic House-Tree-Person drawings was established based on the indexes of Buck(1948) and Bums(1972) and used exiting literatures as reference. The data were analyzed using means, standard deviations, t-test, one-way ANOVA, and Scheffe's test. The results obtained from the study are as follows: First, the mean level of college students' self-differentiation was 2.81, which is about average. Some significant gender differences were found in the areas of self-intergration, family projection, and emotional separation. Male students scored higher on self-intergration, whereas female students score higher on family projection and emotional separation. Second. self-differentiation was higher when the student drew a house with smoke coming out of the chimney, a single-story house with flat roof, or with detailed description of curtains, roof and roof tiles. Third, self-differentiation seemed to be higher when branches and fruits were included, when there was no expression of roots, when large crowns and branch openings were presented, and when no slant lines or base lines appeared. Forth, self-differentiation showed ㅁ higher level when the portrait shows eyes, mouth and neck without omission, when it included the whole body instead of face only, and when there was no person with just a profile, a back, or with a stiff posture, and when there was no weak and thin lines. Individuality also marked higher if a person was in motion and than one person was added. Finally, self-differentiation showed significant difference according to the overall harmony of the drawing, ordering of contents, hand pressure, the kind and shape of tree, and presence of other persons. The more harmonious the picture was, and the more family members are added, the higher the level of self-differentiation was.

Tactility and Mechanical Properties of Marketing Towel (타월용 시판소재의 촉감과 역학적 특성)

  • Jung, Ha-Kyung;Kim, Sun-Kyung;Cho, Hyo-Sook;Kim, Joo-Yong
    • Journal of the Korean Home Economics Association
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    • v.44 no.10
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    • pp.57-66
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    • 2006
  • The purpose of this study was to evaluate the relationship between the tactile sensation and mechanical properties of towel. Six kinds of towels with different surface structure and fiber composition were used for this study. To evaluate the tactility of towel, 36 adjectives were collected and then 11 adjectives were selected. The subjective evaluation was examined by one to one comparative method and by blind test for estimating the only the sense of touch of the towels. Kawabata's Evaluation system for fabrics was used to measure the mechanical properties which are tensile, bending, shear, compression, surface, weight, and thickness of six towels. The results are as follows; First, surface structure of the towels had an effect on estimation the sense of touch. Pile surface was evaluated thicker, compacter, more cushiony, and more elastic. Waffle surface was evaluated knottier and rougher, and microfiber suede surface was evaluated softer and denser. Second, the highest value of the mechanical properties measured were G, 2HG, B, and SMD of 100% cotton 100% pile, WC, T, and W of elban loop pile, WT, 2HB, and LC of 100% cotton cut pile, RT and MIU of microfiber suede, and RC of microfiber waffle. Third, the 11 adjectives were correlated with more than one mechanical property. 'Knotty' and 'rough' were correlated with MMD and SMD, 'soft' were correlated with B, 2HB, MMD, and SMD. 'Thick', 'heavy', 'compact', and 'elastic' were correlated with WC, T, and W, 'cushiony' was correlated with WC. 'Stiff' was correlated with B and 2HB, 'dry out' was correlated with RT, WC, MIU, and T. 'Dense' was correlated with RT and SMD.

A study on the analysis of bearing reaction forces and hull deflections affecting shaft alignment using strain gauges for a 50,000 DWT oil/chemical tanker (스트레인 게이지를 이용한 5만 DWT급 석유화학제품운반선의 베어링 반력 및 선체변형량 분석에 관한 연구)

  • Lee, Jae-Ung
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.4
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    • pp.288-294
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    • 2016
  • In modern ships, the shafting system often becomes stiff owing to the high engine power, whereas the hull structure becomes more flexible owing to optimization using high-tensile-strength thick steel plates; therefore, more sophisticated shaft alignments are required. In this study, strain gauge-based measurement was conducted under five vessel operating conditions and bearing reaction forces and hull deflections affecting shaft alignment were analyzed for a 50,000 dead weight tonnage oil/chemical tanker that has gained repute as an eco-friendly vessel in recent years. Furthermore, the analytical results from each technique-theoretical calculation, jacking ups, and strain gauges-were cross-checked against each other in order to enhance the degree of accuracy and reliability of the calculation.

Improved capacity spectrum method with inelastic displacement ratio considering higher mode effects

  • Han, Sang Whan;Ha, Sung Jin;Moon, Ki Hoon;Shin, Myoungsu
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.587-607
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    • 2014
  • Progressive collapse, which is referred to as the collapse of the entire building under local damages, is a common failure mode happened by earthquakes. The collapse process highly depends on the whole structural system. Since, asymmetry of the building plan leads to the local damage concentration; it may intensify the progressive collapse mechanism of asymmetric buildings. In this research the progressive collapse of regular and irregular 6-story RC ordinary moment resisting frame buildings are studied in the presence of the earthquake loads. Collapse process and collapse propagation are investigated using nonlinear time history analyses (NLTHA) in buildings with 5%, 15% and 25% mass asymmetry with respect to the number of collapsed hinges and story drifts criteria. Results show that increasing the value of mass eccentricity makes the asymmetric buildings become unstable earlier and in the early stages with lower number of the collapsed hinges. So, with increasing the mass eccentricity in building, instability and collapse of the entire building occurs earlier, with lower potential of the progressive collapse. It is also demonstrated that with increasing the mass asymmetry the decreasing trend of the number of collapsed beam and column hinges is approximately similar to the decreasing trend in the average story drifts of the mass centers and stiff edges. So, as an alternative to a much difficult-to-calculate local response parameter of the number of collapsed hinges, the story drift, as a global response parameter, measures the potential of progressive collapse more easily.

Operative Treatment of Unstable Fracture of the Proximal Humerus (상완골 근위부 불안정성 골절의 수술적 치료)

  • Kim Young-Kyu;Jang Young-Hun;Kim Keon-Beom
    • Clinics in Shoulder and Elbow
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    • v.1 no.2
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    • pp.198-204
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    • 1998
  • Unstable fractures of the proximal humerus continue to be difficult problems for orthopaedic surgeons. The optimum treatment of these fractures has remained a matter of controversy. We analyzed the clinical results of open reduction and plate fixation underwent for patients of unstable fractures of proximal humerus after minimum 12 months follow up. The purpose of this study is to evaluate the efficacy of open reduction and rigid plate fixation. Twenty-two patients were managed with open reduction and plate fixation. Mean follow up duration was 20.6 months(range, 12 to 28 mon.). Because the age of patient as a maker of degree of osteoporosis was considered the key factor in the success of anatomic reconstruction, we divided into two groups according to age. Group A was comprised of 12 cases with younger than 50 yrs of age. Ten cases of older than 50 yrs of age were Group B. According to Neer's classification, five cases(22%) were two part fracture, 12 cases(64%) were three part fracture, and three cases(14%) were four part fracture. We used the Neer rating system for evaluating the results. In Group A, overall scores were 79.1. In Group B, overall scores were 76.8. Overall scores in two part fracture were 85, overall scores in three part fracture 78.4 and overall scores in three part fracture 68.3. We achieved excellent or good results in nine cases(75%) of Group A and seven cases(70%) of Group B. Also, we obtained excellent or good results in all cases of two part fracture, ten cases(71%) of three fracture and one case(33%) of four part fracture. The complications were three metal loosening, one avascular necrosis of humeral head, one severe stiff shoulder, one superficial wound infection and one ectopic ossification. The results were excellent or good in 16 cases(73%) out of 22 cases. In conclusion, rigid fixation and supervised early exercise would be a good option for unstable fracture of the proximal humerus.

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Dynamic Analysis of A High Mobility Tracked Vehicle Using Compliant Track Link Model (유연성 궤도 모델을 사용한 고기동성 궤도차량의 동역학 해석)

  • 백운경;최진환;배대성
    • Journal of KSNVE
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    • v.9 no.6
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    • pp.1259-1266
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    • 1999
  • The objective of this investigation is to develop a compliant track link model and apply this model to the multi-body dynamic analysis of high mobility tracked vehicles. Two major difficulties encountered in developing the compliant track models. The first one is that the integration step size must be kept small in order to maintain the numerical stability of the solution. This solution deals with high oscillatory signals resulting from the impulsive contact forces and stiff compliant elements to represent the joints between the track links. The second difficulty is due to the large number of the system equations of motion of the three dimensional multibody tracked vehicle model. This problem was sloved by decoupling the equations of motion of the chassis subsystem and the track subsystems. Recursive methods are used to obtain a minimum set of equations for the chassis subsystem. Several simulation scenarios were tested for the high mobility tracked vehicle including accelaeration, high speed cruising, braking, and turning motion in order to demonstrate the effectiveness and validity of the methods proposed in this investigation.

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A Study on the Physical Properties of Silk Fabrics - Bending and Luster Properties - (견직물(絹織物)의 물리적(物理的) 특성(特性) 변화(變化)에 대(對)한 연구(硏究) - 굽힘 및 광택(光澤) 특성(特性)-)

  • Park, Shin-Jung;Kim, Jong-Jun;Jeon, Dong-Won
    • Journal of Fashion Business
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    • v.8 no.5
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    • pp.31-40
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    • 2004
  • The purpose of this study is to investigate the change of the physical properties, bending and luster properties, which are related to the touch and appearance of silk fabrics modified by the degumming process. The silk has long been known as one of the most elegant and soft textile materials. The raw silk yarn, or cocoon bave, spun from the spinneret, is rather stiff due to the sericin covering the two fibroins together. The sericin can be removed during a degumming process. The removal of the sericin would result in remarkable change in the physical properties of the raw silk fabrics, including luster of the fabrics, which process parameters could possibly be utilized to adequately control the silk fabric properties. The KES(Kawabata Evaluation System) is a testing methodology that has been used with considerable success for predicting the hand and tailorability of apparel fabrics. This study uses one of the KES, bending tester, to measure the bending properties of the silk fabrics degummed for specified period to change the physical/mechanical properties of the fabric. The KES bending measurement revealed that the bending rigidity decreased for both the warp and weft direction of the silk fabrics with the increase of the degumming period. It has been shown in this study that the some of the hand-related physical properties, including the bending rigidity, drapability, and luster, could be modified with the change in the degumming period.

The Effect of Persimmon Juice Treatment on Hand Values of the Silk Organza (감즙처리가 견직물의 태에 미치는 영향)

  • Yoo Hye-Ja;Lee Hye-Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.5 s.153
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    • pp.772-778
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    • 2006
  • Silk organza can make the silhouette of clothes bulky and rich, owing to its stiffness. And silk organza in the gum has better dyeability so can be dyed more bright and deeper color than scoured silk because silk organza has sericin gum that has better dyeability than fibroin. So, silk organza came into the most broad use as the material for Hanbok, especially in summer. But the silk organza has poor color fastness. Sericin is removed from organza when silk organza go through scouring. The purpose of this research is to find out the optimum conditions that the scoured silk fabrics can get stiffness by persimmon juice treatment. For experiments, non scoured, partially scoured and fully scoured silk fabrics were prepared by alkali treatments. Then 3 kinds of silk fabrics were treated with the concentration of 1, 5, 10, 50 and 100% of persimmon Juice. The change of fiber surface of the various silk fabrics were observed By SEM. The hand values of those fabric samples also were measured hand values by Kawabata Evaluation System and stiffness by Cantilaver method. By scouring, the silk organza got more flexibility and less cohesiveness between their fibers. And it can be a little more bulky by removing gum. Namely, silk organza lost its unique stiff and crisp handle. By the persimmon juice treatment, tannin component could be coated on the fiber surface. so that the stiffness of the fabrics were improved.