• Title/Summary/Keyword: Single impact

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Development and Evaluation of Fall Impact Protection Pad (낙상충격 보호패드의 개발 및 평가)

  • Park, Jung Hyun;Lee, Jin Suk;Lee, Jeong Ran
    • Fashion & Textile Research Journal
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    • v.20 no.4
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    • pp.422-428
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    • 2018
  • In this study, we developed honeycomb pads using foam and polymer gel and verified the impact protection performance of pads for the development of a fall protection pants for elderly women aged 65 and over who have a high risk of fracture due to falls. The results are as follows; In the first experiment, the impact protection performance was evaluated for four honeycomb pad samples (CR foam, EPDM foam, hardness 15 polymer gel, and hardness 30 polymer gel) manufactured to a thickness of 5 mm using a single material. When the force of about 10757N was applied to the specimens, all four pads reduced the impact force to 3100N or less. Polymer gels showed better protection than foam materials. In the second experiment, the thickness of the protective pad was set to 8 mm in order to improve the shock absorbing performance of the protective pad. As a result of evaluating the impact protection performance of the foam single pad and foam gel composite pad, the impact absorbing performance of the foam single pad was better. Finally, four kinds of protection pads were made by assigning the foam single pad and the foam gel composite pad to pants type and underwear type respectively. The pad thickness of the main protection area was set to 8 mm to enhance the protection, and gradually decreased to 5mm and 3mm toward the edge to improve the appearance and fit.

Analysis of Consumption Preference for HMR According to Single-person Household (1인 가구의 간편식 소비 선호도 분석 연구)

  • Woo, Won-Seok;Hwang, Jae-Hyun
    • Korean Journal of Organic Agriculture
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    • v.28 no.3
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    • pp.347-365
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    • 2020
  • In South Korea, social, the number of single-person households has rapidly increased because of financial factors. Since single-person households have characteristics differentiated from general households, many enterprises pay attention to them that appear as important consumers. This study conducted a survey with consumers in their 20s to 50s in single-person households, nationwide who had an experience of purchasing HMR. The results of this study can be summarized as follows: First, of the benefits pursued in dietary life, the pursuit of nutrition a negative (-) impact on RTH type and did not have any impacts on the RTE and RTC types. The pursuit of taste had a positive (+) impact only on the RTE type while it did not have any impact on the RTH and RTC types. The pursuit of convenience had positive (+) impacts on all RTH, RTE and RTC types, while the pursuit of price sought did not have any impact on all types. Second, of the preferences by each HMR type, preferences for the RTH and RTC types had positive (+) impacts on purchase intention while preference for the RTE type did not have any impact on purchase intention. Third, of the benefits pursued in dietary life, the pursuits of taste and convenience had positive (+) impacts on purchase intention while the pursuits of nutrition and price did not have any significant impacts on purchase intention. In addition, of the benefits pursued in dietary life, the pursuit of convenience had a significant impact on purchase intention mediated by preference by each HMR type. As a result, taste of HMR and the aspects of convenience act as factors inducing purchases, and products in the various forms of taste and convenience in order to appeal consumers who pursue taste and convenience.

The Effects of Boundary Condition in Cone Crack Formation of Soda-lime Glass by Ball Impact (볼 충격을 받는 유리의 콘크랙형성에 대한 경계조건의 영향)

  • Kim, Moon-Saeng;Heo, Jin;Lee, Hyeon-Chul;Kim, Ho-Jong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.6
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    • pp.981-986
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    • 2003
  • In order to investigate the possibility of processing of brittle material by ball impact, the effects of boundary conditions about impact damage of soda-lime glass by small spheres were evaluated experimentally. It was investigated that crack appearance developed in soda-lime glass with boundary conditions of without sealing, single-sealing and double-sealing by impact velocity. The double-sealing was most effective in the development of perfect cone than other boundary condition. In case of double-sealing condition, PVC and Polyurethane sealing were more effective in producing a perfect cone formation than other sealing materials. The impact velocity range over which perfect cones were formed was influenced by both the contact area and diameter of impact particle.

Evaluation of the Impact Force on the Single Spray and Overlap Region of Twin Spray in Full Cone Type Swirl Nozzle (Full Cone Type 스월노즐에서 단일분무와 이중분무의 중첩영역에 대한 충격력 평가)

  • Kim, T.H.;Sung,, Y.M.;Jeong, H.C.;Kim, D.J.;Choi, G.M.
    • Journal of ILASS-Korea
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    • v.16 no.1
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    • pp.27-36
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    • 2011
  • The impact force on the single and overlap region of twin spray was experimentally evaluated using visualization method in full cone type swirl nozzle spray. Visualization of spray was conducted to obtain the spray angle and breakup process. The photography/imaging technique, based on Particle Image Velocimetry (PIV) using high-speed camera, was adopted for the direct observation of droplet motion and axial velocity measurement, respectively. Droplet size was measured by Particle Motion Analyze System (PMAS). The purpose of this study is to provide fundamental information of spray characteristics, such as impact force, for higher etching factor in the practical wet etching system. It was found that the spray angle, axial velocity and impact force were increased with increasing the nozzle pressure while droplet size decreased with increasing the nozzle pressure. Droplet size increased as the distance from nozzle tip was decreased. The impact force of twin spray in the overlap region was about 63.29, 67.02, 52.41% higher than that of single spray at 40, 50 and 60 mm of nozzle pitch, respectively. Also, the nozzle pitch was one of the important factors in the twin spray characteristics.

The Cost Impact of Information Delay in a Supply Chain

  • Kim Heung-Kyu
    • Management Science and Financial Engineering
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    • v.12 no.1
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    • pp.1-34
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    • 2006
  • In this paper, the impact of information sharing, possibly with some delay, on costs in a simple supply chain in which there are two participants, a single retailer and a single manufacturer, is considered. When participants in the supply chain do not use fully integrated EDI, some delay associated with information sharing is inevitable. A mathematical model that allows us to quantify the cost incurred by the manufacturer in the supply chain under information sharing, possibly with some delay, vs. no information sharing is presented. From this model, some managerial implications are gleaned.

Impact of LDD Structure on Single-Poly EEPROM Characteristics

  • Na, Kee-Yeol;Park, Mun-Woo;Kim, Kyung-Hoon;Kim, Nan-Soo;Kim, Yeong-Seuk
    • Journal of Electrical Engineering and information Science
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    • v.3 no.3
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    • pp.391-395
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    • 1998
  • The impact of LDD structure on the single-poly EEPROMs is investigated in this paper. The single-poly EEPROMs are fabricated using the 0.8$\mu\textrm{m}$ CMOS ASIC process. The single-poly EEPROMs with LDD structure have slower program and erase speeds, but the drain and gate stresses and the endurance characteristics of these devices are much better than those of the single-poly EEPROMs with single-drain structure. The single-poly EEPROMs with LDD structure do not require the process modifications and need no additional masks, hence can be used for microprocessors and logic circuits with low-density and low-cost embedded EEPROMs.

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An Impact Analysis of Adhesively-Bonded Single Lap Joint (단면 겹치기 접착 조인트의 충돌해석)

  • Lee, Ju-Won;Na, Won-Bae
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.172-177
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    • 2010
  • This study presents an explicit dynamic analysis of an adhesively bonded single-lap joint under an impact load. The finite element software, ANSYS LS-DYNA, was used for the analysis and Von Mises stresses were obtained from the analysis. To model the adherents, solid elements were used and a rigid body was assumed for impactor modeling. Three impact heights (1 m, 5 m, and 10 m) were applied to consider different impact conditions and infinite boundary conditions were applied to the end-area of each adherent to save computational time in the analysis. In addition to investigating the stresses in the normal state, we also investigated the stresses in a damaged state (elasticity deterioration), simulated by a change in Young's modulus for 36 of the 3600 elements in the upper layer of the adhesive. The results showed that the location of damage is critical to the stress state of each layer (upper, middle, and lower).

Comparison of Impact Sound Insulation Performances of Apartment Floors Against Heavy-weight Impact Sources via Field Measurement Data (공동주택 현장 측정자료를 활용한 중량충격원의 바닥충격음 차단성능 비교)

  • Yun, Chang-Yeon;Yeon, Jun-Oh;Kim, Myung-Jun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.8
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    • pp.651-658
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    • 2014
  • Notification 2013-611 of MOLIT has come into effect. It relates primarily to new standard impact source. In this study, an in-depth experimental analysis of the difference between a bang machine and an impact ball was performed via field testing of shear wall and flat plate structure at 51 sites. This paper focuses on the difference in single number quantities between a bang machine and an impact ball. At wall thicknesses of 180 and 210 mm in shear wall structure, the single number quantities exhibited differences of 3.1 and 4.5 dB, respectively, and at thicknesses exceeding 250 mm in flat plate structure, the difference was constant at 4.6 dB. With regard to flat plate structures, the single-index difference increased up to 11 dB as the thickness of the floor slab increased. In general, the highest level of contribution for the bang machine was 63 Hz, irrespective of thickness determining bandwidth. The highest level for the impact ball were 63 Hz and 125 Hz. In future research, when reviewing additional field performance measurement data, it will be necessary to consider a detailed examination instead of the current method of uniformly adding 3 dB for all thicknesses and types of structures.

The impact analysis of interface crack in dissimilar materials using the 2-D laplace transformed BEM (2차원 Laplace 변환 경계요소법에 의한 이종재료 접합면 균열의 충격해석)

  • 김태규;조상봉;최선호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.5
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    • pp.1158-1168
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    • 1994
  • For BEM analyses of the impact problems of dissimilar materials, the connected multi-region method using perfect bonded conditions on the interface boundaries was added to two-dimensional Laplace transformed-domain BEM program for a single region analysis. It was confirmed that the BEM results of impact problems of a single-region and multi-regions for a homogeneous isotropic material are agreed well. The two-dimensional Laplace transformed-domain BEM program combined with connected multi-region method was applied to analyse several impact problems of dissimilar materials. Also the feasibility of BEM impact analyses was investigated for dissimilar materials by the analysis of the BEM results for impact problems of dissimilar materials in terms of physical aspects. As for an application, the two-dimensional Laplace transformed BEM concerning impact problems of cracks at the interface of dissimilar materials and the determinating process of the dynamic stress intensity factors by extrapolation method are presented in this paper.

Determination of Impact Source Location Using a Single Transducer and Time Reversal Technique (단일센서와 시간역전법을 이용한 판에서의 충격위치 결정에 관한 연구)

  • Jeong, Hyun-Jo;Cho, Sung-Jong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.1
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    • pp.47-55
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    • 2012
  • A structural health monitoring technique for locating impact position in a plate structure is presented in this paper. The method employs a single sensor and spatial focusing of time reversal (TR) acoustics. We first examine the TR focusing effect at the impact position and its surroundings through simulation and experiment. The imaging results of impact points show that the impact source location can be accurately estimated in any position of the plate. Compared to existing techniques for locating impact or acoustic emission source, the proposed method has the benefits of using a single sensor and not requiring material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in other ultrasonic testings of plate-like structures.