• 대한조선학회논문집
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• 제54권6호
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• pp.522-529
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• 2017

Air gun shock system is used as an alternative energy source as part of the attempt to overcome the restrictions of economical expense and environmental damage, etc., due to the use of explosives for the UNDerwater EXplosion (UNDEX) shock test. The objectivity of this study is to develop the simulation technique of air gun shock test for the design of model-scale one for the near field non-explosive UNDEX test through its verification with full-scale SERCEL shock test result. Underwater blasting response analysis of full-scale air gun shock test was carried out using highly advanced M&S (Modeling & Simulation) system of FSI (Fluid-Structure Interaction) analysis technique of LS-DYNA code, and was verified by comparing its shock characteristics and behaviors with the results of air gun shock test.

• 한국환경과학회지
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• 제3권3호
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• pp.285-296
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• 1994

The objective of this study was to examine and compare to transient response to quantitative and hydraulic shocks which produce equal changes in mass rate of organic feed in aerobic fixed-film process. The general experimental approach was to operate the system at several growth rates under steady-state(pre-shock) conditions, then to apply step changes during day 3 in dilution rate(hydraulic shock) , or feed concentration(Quantitative shock) at the same organic mass loading rate. Performance was assessed in both the transient state and the new steady-state (post- shock). Shock load of different type did not produced equivalent disruptions of effluent quality for equal increases in mass loading rate. Based on effluent concentrations, a hydraulic and a Quantitative shock at the same mass loading caused equal increase in total effluent COD, but the increase was primarily a result of suspended solids the hydraulic shock and COD in the quantitative shock. The time which effluent COD came to peak values were about 32~48 hours at the low organic loads and 52 ~ 72 hours at the high organic loads, respectively A quantitative shock produced a much greater increase in effluent COD than did a hydraulic shock at the same mass loading. Mean and peak values of effluent concentration weve increased in 2.8~4.2 times at low organic loading rate, 5.2~6.6 times at the high organic loading rate, respectively. Key words : Aerobic fixed-film reactor, Quantitative shock, hydraulic shock, mass loading rate.

• 상하수도학회지
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• 제11권3호
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• pp.67-78
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• 1997

The objective of study was to examine to transient response of hydraulic shock loading in activated sludge process for treatment of municipal sewage. The general experiment approach was to operate the system under steady-state(pre-shock), then to apply step changes during 24hours in fourfold hydraulic shock loading at the same organic loading. Performance was assessed in both the transient state and the new steady-state(post-shock). Three bench scale activated sludge reactors were operated to investigate the effect of fourfold hydraulic shock loading on TSS and COD removal efficiency. In activated sludge reactors operated with 13hours and 7hours of HRT, effluent quality of all reactors was not changed for few effects, and also showed no foaming and no sludge bulking. Those results are the same as sludge withdrawn reactors. The effect of fourfold hydraulic shock loading on the activated sludge reactors operated with 3hours of HRT was most severe. The effluent quality was deteriorated significantly and generate foaming in reactors. Less than 24hours after the fourfold shock loading applied, the activated sludge system seemed to attain a new steady-state condition as show by effluent.

• 한국군사과학기술학회지
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• 제24권5호
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• pp.503-510
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• 2021

This paper presents a system that measures the acceleration of the shock caused by the explosion of the precursor warhead for the tandem projectile. The proposed system, which is implemented based on the MIL-STD-810G, Method 517.1, consists of a miniaturized shock measurement device, a cable, accelerometers, and a trigger circuit. The shock measurement device has a size of ¢102 × 171 mm and cable has a length of 3 m. The operational confirmation test is conducted by implementing the measurement system. The Analysis of shock data(accelerometer output data) is carried out using Shock Response Spectrum(SRS), pseudo velocity and plot of acceleration time transient. Through measurement analysis, one can predict the damage of electronics in projectile when precursor warhead is exploded.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.761-765
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• 2001

Shock responses of the MIL-S-901D standard floating shock platform("SFSP") subject to underwater explosions(UNDEX) are analyzed by using the LS-DYNA/USA. For the analysis, surrounding fluids as well as the SFSP are included in a 3D FE model to consider the cavitation effects of the UNDEX shock wave. The calculated results are compared with the existing test results and it is confirmed that the analysis results predict accurately the shock behaviors of the SFSP.

• BMB Reports
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• 제42권10호
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• pp.631-635
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• 2009

The heat shock transcription factor (HSF) family consists of at least three members in mammals and regulates expression of heat shock proteins in response to heat shock and proteotoxic stresses. Especially, HSF1 is indispensable for this response. Members of this family are also involved in development of some tissues such as the brain and reproductive organs. However, we did not know the molecular mechanisms that regulate developmental processes. Involvement of HSFs in the sensory development was implicated by the finding that human hereditary cataract is associated with mutations of the HSF4 gene. Analysis of gene-disrupted mice showed that HSF4 and HSF1 are required for the lens and the olfactory epithelium, respectively. Furthermore, a common molecular mechanism that regulates developmental processes was revealed by analyzing roles of HSFs in the two developmentally-related organs.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.173-176
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• 2004

Nowadays, mobile devices are very common equipments such as mobile phone, PDA, etc. These equipments need information storage devices. Optical storage devices have more advantages than other storage devices, but it is not free from shock situation like dropping by user's mistakes. A complete model of a Small Form Factor Optical(SFFO) disk drive subject to shock loads is developed to investigate the response of the pickup/disk interface. With this model, we can simulate the drop test and consider the matters of shock simulation using commercial software(Ansys/LS-Dyna).

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.892-898
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• 2009

In this paper, a cause of a shock of an industrial chop saw is identified by experimental method and the shock is reduced by structural modifications. For the shock identification, vibration signals are measured by an accelerometer when the chop saw operates. Through some experiments, it is found that the shock is occurred by a slip between a spindle and a wheelwasher of the chop saw. To reduce the shock, One method is to lower the mass moment of inertia of the wheelwasher and the angular rotating acceleration of it. Another method is to broaden a contact area between the wheelwasher and the spindle. After designing and analyzing the wheelwasher and the spindle mechanically, a prototype of them is built. With the manufactured prototype, the performances and design requirements of them are experimentally verified by the response measurements.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.215-216
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• 2005

Nowadays, mobility as well as basic performances has been the important performance index of hard disk drive, It makes a system unstable to satisfy mobility, huge storage capacity and high transfer rate. Shock and vibration analysis has been important because hard disk drive could be exposed by external shock and vibration. The probability of this situation has been increasing. In this research, each component and the whole system of 2.5in HDD are made to a finite element model. Results of finite element analysis are compared with the results of experimental modal analysis. Shock analysis is executed for 2.5in hard disk drive.

• 대한기계학회논문집A
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• 제31권2호
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• pp.145-151
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• 2007

Impulsive excitation on vehicle produces shock-type vibration on the seat, which has major frequencies and damping ratios dependent on the characteristics of the suspension, the tire, the seat cushion and so on. The response of single degree of freedom model to a half-sine force input was considered as simple shock-type vibration signal. Quasi-apparent-mass for fifteen subjects was measured with the shock-type vibration generated on a rigid seat mounted on the simulator, so its nonlinearity was apparently found over 6.3 Hz according to the difference of magnitude of the shock.