• Explosives and Blasting
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• v.35 no.4
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• pp.19-26
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• 2017

The most widely used method for determining the blast effects of explosives is the Trauzl lead block test. This test is used to measure the explosive power (strength) of a substance by determining volume increase, which is produced by the detonation of a test explosive charged in the cavity of a lead block with defined quantity and size. In this paper, Trazul lead block test and AUTODYN numerical analysis were conducted to evaluate the coupling medium effect of blast hole. The effects of coupling materials can be expressed as the expansion of the cavity in a standard lead block through explosion of the explosives. The tests were conducted with emulsion explosives. The coupling mediums used as the filling material around a explosive charge were air, sand, water and gelatine. Results of test and numerical analysis showed that expansion of lead block were much more affected by water&gel than by sand and air. The water and gel showed similar results. As expected, the transmitted pressure and dynamic strain was higher in water and gelatine coupled blast hole than in air and sand.

• Explosives and Blasting
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• v.36 no.4
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• pp.35-47
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• 2018

In this study, several concrete-block blast tests and AUTODYN numerical analyses were conducted to analyze the effects of different stemming and coupling materials on explosion results. Air, sand, and polymer gel were used as both the stemming and coupling materials. The stemming and coupling effects of these materials were compared with those of the full-charge condition. Soil-covered or buried concrete blocks were used for field crater tests. It was found from the concrete block tests and numerical analyses that both the crater size and the peak pressure around the blast hole were higher when the polymer gel was used than when the sand and the decoupling condition were used. The numerical analyses revealed the same trend as those of the field tests. Pressure peaks in concrete block models were calculated to be 37, 30, and 16 MPa, respectively, for the cases of the polymer gel, sand, and no stemming and decoupling condition. The pressure peak was 52 MPa in the case of full-charge condition, which was the highest pressure. But the damage area for the case was smaller than that obtained from the use of polymer gel. Full-charge was also used as a reference test.

• Explosives and Blasting
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• v.34 no.4
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• pp.40-45
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• 2016

Sites, where explosives are used, are constantly under constraint of vibration and noise levels. If a sensitive area is located nearby the sites, mechanical excavation has been preferred rather than blasting. Recently, however, blasting using electronic detonators is applicable in the areas, where previously should be excavated by mechanical methods. $HiTRONIC^{TM}$ is a fourth-generation detonator that utilizes Hanwha Corporation's advanced electronic technology. The detonator contains IC-Chip, which allows delay times between 0~15,000ms with 1ms interval. Furthermore, the product can provide high accuracy(0.01%) for accurate-blasting. Electronic detonator is widely used in highway and railway construction sites, large limestone quarries, and other works. In this paper, several sites, in which HiTRONIC was used, are introduced in order to enhance understanding of electronic detonator.

• Journal of Korean Medical classics
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• v.19 no.2 s.33
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• pp.163-178
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• 2006

향의약학영향료직접효력적의약정책급위료관철적양정책입적의약조직기구화각충의약사병제도등(向?約學影向了直接效歷的?約政策及危了關鐵的洋政策立的?約組織紀柩和各忠?約事?制度等), 도시현대의정관리화약정관리체계적구성부분(都是現代?政管理和約政管理?系的柩成部分). 의정관리화약정관리도보건복지적중요구성부분(?政管理和約政管理都保健福祉的重要柩成部分). 의정화약정책명사개념자동근현대개시사용적(?政和約政策名?槪念自洞近現代開始使用的), 불과본논문상언급적개념도시왕조사회적내용(不過本?文上言及的槪念都是王朝社會的內容). 진관왕조사회몰용의정화약정저명사개념(進管王朝社會沒用?政和約政這名?槪念). 단시여현대적의정화약정개념차불다일양(但是?現代的?政和約政槪念差不多一洋). 유이본논문상용현대적‘의정’개념개전연구(由而本?文上用現代的‘?政’槪念開展硏究), 관우재왕조사회상의정병기영향의학발전(?于在王朝社會上?政幷基影響?學發展). 논자최근화중국양준교수합작병진행관우자종진한시대도청조적의정사공동연구(?者最近和中國梁畯敎授合作幷進行?于自種秦漢時代到淸朝的?政史共同硏究), 파타당작기근향후한의학유관적아국정책급교육(把?當作基根向后韓?學有?的我國政策及敎育), 보건행정등방면상(保健行政等方面上), 반망활용이참고자료(盼望活用以參考資料). 본몬문시저반연구작업제일두서(本論文是疽般硏究作業第一斗緖), 지우자종형성중국최초통일국가적진조도한조적의정사(至于自種形成中國最初統一國家的秦朝到漢朝的?政史), 진한적정책개요(秦漢的政策槪要), 진한의약정책(秦漢?約政策), 관우의정기구진한의관제도적작용(?于?政肌柩秦漢?官制度的作用), 진한의약정책화의약발전관계(秦漢?約政策和?約發展?系), 진한의정평가화형성원인등분성오개방면후(秦漢?政?伽和形成原因等分成五介方面后), 진행연구병정리보고기결과(進行硏究幷整理報告基結果).

• Explosives and Blasting
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• v.20 no.4
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• pp.17-28
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• 2002

Safety concern is one of the most important parameters in the design of building demolition by explosive blasting, Accidents were sometimes reported due to the flying chips of fragmented materials In building demolition work in urban area. Laboratory experiments were performed to investigate the failure behavior of reinforced concrete pillars under blast loading and to develop an effective protection technique. Sixteen reinforced concrete pillars were constructed. The failure behavior and the flying chip velocities were observed by means of a high-speed camera. Protection scheme was designed and the effects of several protection materials were investigated. Two kinds of non-woven fabrics and wire net were tested as protection materials. The results showed that reinforcing bar was one of the important factors to determine specific charges, and that mesh size of wire net and tied-up method affected the protection of flying chips. Control of gas effects is also a key to the control of flying chips. It was recommended to use both wire net and non-woven fabrics as primary and secondary protection materials. Such protection scheme was successfully applied to the explosive demolition of apartment buildings.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.3
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• pp.25-31
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• 2016

This research investigated the manufacturing process and characteristics analysis of ZPP(Zirconium Potassium Perchlorate) as pyrotechnic are commonly found in the aerospace, defense, and automotive industries. A solid pyrotechnic mixture is composed of an oxidizing agent, fuel, and binder. Precipitation process was used to uniformly mix the raw material. Through the analysis of the material characteristics and thermal response is designed optimum ratio by NASA CEA program. It was compared by performing the evaluation of these size, shape and calorimetry characteristics.

• Explosives and Blasting
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• v.23 no.2
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• pp.23-35
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• 2005

Excavation of an opening in a saturated porous rock may lead to the development of pore pressure around the opening due to the redistribution of initial rock stresses. The built-up of pore pressure, in turn, may affect the mechanical behavior of rock mass and give the different pattern of stress distribution around the opening from that of the case where the coupling is neglected. In this study, the short time response of an opening excavated in saturated ground under anisotropic initial stress conditions was investigated numerically. Not on the wall of opening but at a short distance from the wall, the tangential stresses were peak during the short period after excavation when the hydro-mechanical coupling is considered.

• Explosives and Blasting
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• v.22 no.2
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• pp.1-11
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• 2004

일반적으로 국내 석회석 광산에서의 발파는 20ms나 25ms 시차를 가지는 지발발파로 시행되어지고 있다. 국외에서는 전자뇌관을 사용하여 암반의 지질학적인 특성에 따라 지발 시차를 사용자의 현장에 따라 선정하여, 주변 보안 물건에 따른 진동 및 소음을 경감하면서, 1회 발파의 생산량을 증대할 수 있으며, 2차 파쇄 비용 및 적재비용을 절감하는 최적의 시차를 적용하여 발파 규모를 줄이지 않는 발파패턴을 적용하고 있다. 본 연구는 해외에서 사용되고 있는 전자뇌관을 국내 현장 석회석 광산(단양)에 적용함으로 최적지연시차를 찾아내는 방법과 초시의 오차에 따른 문제점과 향후 국내 적용성을 판단하고자 하였다. 대규모 석회석 광산을 대상으로 최적시차를 판단하고자 동일 패턴에서 시차를 6ms ~ 30ms로 시험발파를 시행하여 4가지 요소 발파진동속도, 주 주파수특성, 파쇄입도, 암석 이동 및 버력의 상태를 분석하여 각 시차에 따른 배점을 두어, 당 현장에 요구되는 개별 가중치를 선정하여 분석하였다. 분석 결과 당 현장에서의 발파결과에 따른 요소별 가중치를 발파진동속도(20), 주 주파수 특성(20), 파쇄입도(40), 암석 이동(10) 및 버력의 상태(10)로 하여 분석한 결과 15ms가 최적시차로 나타냈다. 향후 각 현장에 적합한 요소별 가중치를 선정하여 현장별 최적시차를 도출한다면 최적의 발파효과를 있을 것으로 판단된다.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.80-84
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• 2015

This paper suggested an error detection process based on multimedia computer supported cooperative works (CSCW) for industry safety environment. This system is suitable for detecting software fault for multimedia CSCW. It is necessary of detecting an error for the system to be protected by reactivity of media service instance instead of breaking process of session. This paper describes a performance analysis of an error detecting system of function comparison of proposed method with other method based multimedia CSCW for explosives as an example of industry safety environment.

• Explosives and Blasting
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• v.31 no.1
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• pp.49-54
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• 2013

External charges with four different kinds of tamping materials are tested to determine the effect of tamping on the blasting of steel components and concrete blocks. The tamping materials used are tamping cap, urethane foam, sand bag and mud. As a result, the tamping cap, urethane foam, and sand bag show no significant effect of tamping. But the mud tamping shows that the charge amount can be reduced by more than 20% in completely cutting the structural components. In addition, it is found from the test that the standard equation for calculating the proper charge is rather conservative, which means the equation overestimates the necessary charge for the blasting.