WorldWideScience

Sample records for blast effects

  1. Blast effects of external explosions

    OpenAIRE

    Sochet, Isabelle

    2010-01-01

    International audience Security considerations for industrial production and storage require characterization of the mechanical effects caused by blast waves resulting from a detonation or deflagration. This paper evaluates current analytical methods to determine the characteristic parameters of a blast wave with respect to the pressure, impulse and duration of the positive phase of the blast. In the case of a detonation, the trinitrotoluene (TNT) equivalent-based method determines the mas...

  2. Influence Mechanism of Lamella Joints on Tunnel Blasting Effect

    OpenAIRE

    Shiwei Shen; Lei Nie; Shulin Dai; Yan Xu

    2013-01-01

    In this study, we have a research of the influence mechanism of lamella joints on tunnel blasting effect. During the process of the tunnel blasting construction, primary structural planes make an important role for the effect of smooth blasting. Especially, it is difficult to attain the perfect blasting effect when the lamella joints intersect with the designed contour line. Coupled effect of the explosive stress waves and the explosive gas is deemed to the basic theory, analysis the blasting...

  3. Effectiveness of eye armor during blast loading.

    Science.gov (United States)

    Bailoor, Shantanu; Bhardwaj, Rajneesh; Nguyen, Thao D

    2015-11-01

    Ocular trauma is one of the most common types of combat injuries resulting from the interaction of military personnel with improvised explosive devices. Ocular blast injury mechanisms are complex, and trauma may occur through various injury mechanisms. However, primary blast injuries (PBI) are an important cause of ocular trauma that may go unnoticed and result in significant damage to internal ocular tissues and visual impairment. Further, the effectiveness of commonly employed eye armor, designed for ballistic and laser protection, in lessening the severity of adverse blast overpressures (BOP) is unknown. In this paper, we employed a three-dimensional (3D) fluid-structure interaction computational model for assessing effectiveness of the eye armor during blast loading on human eyes and validated results against free field blast measurements by Bentz and Grimm (2013). Numerical simulations show that the blast waves focused on the ocular region because of reflections from surrounding facial features and resulted in considerable increase in BOP. We evaluated the effectiveness of spectacles and goggles in mitigating the pressure loading using the computational model. Our results corroborate experimental measurements showing that the goggles were more effective than spectacles in mitigating BOP loading on the eye. Numerical results confirmed that the goggles significantly reduced blast wave penetration in the space between the armor and the eyes and provided larger clearance space for blast wave expansion after penetration than the spectacles. The spectacles as well as the goggles were more effective in reducing reflected BOP at higher charge mass because of the larger decrease in dynamic pressures after the impact. The goggles provided greater benefit of reducing the peak pressure than the spectacles for lower charge mass. However, the goggles resulted in moderate, sustained elevated pressure loading on the eye, that became 50-100% larger than the pressure loading

  4. Effects of grit blasting on surface properties of steel substrates

    International Nuclear Information System (INIS)

    Low carbon steel substrates have been grit blasted using alumina grits of various sizes under varying pressure, time, angle and standoff distances and the corresponding effect on surface roughness and surface residual stress has been studied. The mechanism of material removal in grit blasting has been analyzed. The effect of blasting process parameters on substrate surface residual stress has been studied using a statistically designed experiment. For this purpose the Barkhausen noise analysis (BNA) of the blasted surface has been undertaken. Then the BNA results have been calibrated against and complemented using the residual stress values measured using X-ray diffraction. The correlation between BN signal and the measured residual stress has been studied. The material removal in blasting takes place by microcutting, indentation or by a mixed mode depending on the blasting angle. During blasting the alumina grits themselves also undergo erosion. The analysis of the experimental results shows that the surface roughness increases with grit size, blasting pressure and to an extent with blasting time and blasting angle as well. The compressive residual stress of the surface and subsurface hardness increases with blasting pressure and blasting angle. The Barkhausen noise signal has a strong correlation with the magnitude of the compressive residual stress on the blasted surface.

  5. Seismic effects on the environmental related to blasting series

    OpenAIRE

    Dambov, Risto; Dambov, Ilija; Nikolic, Miroslav; Cacarov, Vladimir

    2015-01-01

    Blasted series performed on surface and underground mines, cause different effects on the environment in terms of intensity of the shocks, air shocks and pieces of blasted rock mass. These negative effects can cause harmful effects on humans and buildings. For protection from the harmful effects introduced standards, criteria and restrictions on the intensity of these effects, especially the allowable intensity of tremors on the ground to some distance from the blasting series. ...

  6. Gas cloud explosions and resulting blast effects

    International Nuclear Information System (INIS)

    The design of nuclear power plant structures to resist blast effects due to chemical explosions requires the determination of load-time functions of possible blast waves. Results of recent investigations show that in a free cloud with deflagrative ignition (flame,heat wire, sparks) the occurrence of a gas detonation can practically be excluded. Apparently, free gas clouds can only be induced to detonate by a sufficiently strong detonative initiation. Independently of the initiating event in the practice of damage analysis, it has become customary to describe the consequences of an explosion by means of the so-called TNT equivalent. Therefore, it is attempted to specify this equivalent for hydrocarbons by means of energetic considerations including the propagation functions for the case of spherically symmetric detonations. Analogous to the safety distances required in the handling and storage of high explosives, a mass-distance relation of the form R = k(L)sup(1/3) could be considered where L is the mass of spontaneously released hydrocarbon and k varies only with the structural shape of the blast loaded buildings. With the inclusion of an empirical relation which relates the quasi-static design pressure for a building with the normally reflected blast pressure of a blast wave, it is further attempted to establish a relation between the structural capacity of a building - i.e. the pressure resistance of a building structure for detonative dynamic loading and for quasi-static loading - and the unit-mass distance R/L 1/3. (Auth.)

  7. Analysis of the blasting effect on the electric shove loading efficiency of the open pit

    Institute of Scientific and Technical Information of China (English)

    FU Tian-guang; SUN Ying

    2008-01-01

    The connection between blasting cost and comprehensive cost is the main concern. Some blasting effect factors (such as unit explosive consumption, uniformity of blockness, shape and porosity of blasting heap), which had an influence on electric shove loading efficiency, were analyzed. In the end a project to properly increase in blasting cost to decrease the comprehensive cost was put forward. At the same time, the hole-by-hole blasting is effective technology to improve blasting effect.

  8. Assessment of Blasting Operations Effects During Highway Tunnel Construction

    Directory of Open Access Journals (Sweden)

    Valašková Veronika

    2015-12-01

    Full Text Available Blasting operations are one of the fundamental parts of daily civil engineering. Drilling and blasting still remain the only possible ways of tunnelling in very adverse geological conditions. However, this method is a source of various disadvantages, the main one being tremors propagating through the geological environment which not only affect buildings, but also disturb the comfort of living in the vicinity of the source. Designing this procedure is mostly done using standardized empirical relations. This article shows the possibility of using a FEM technique in predicting blast effects. This approach is demonstrated in a simple case study on the impact of blasting operations on steel pipes.

  9. Gas cloud explosions and resulting blast effects

    International Nuclear Information System (INIS)

    The design of nuclear power plant structures to resist blast effects due to chemical explosions requires the determination of load-time functions of possible blast waves. Whether the explosion of a hydrocarbon gas in the atmosphere will occur in the form of a deflagration or a detonation is largely depending on the type of the flame acceleration process which is closely related to the rate of energy release. Flame propagations at normal flame velocities in a free explosible gas cloud will certainly not lead to a detonation. With sufficiently large clouds, however, the flame acceleration could become so high that an initial deflagration changes into a detonative process. Results of recent investigations, which will be discussed in detail, show that in a free cloud with deflagrative ignition (flame, heated wire, sparks) the occurrence of a gas detonation can practically be excluded. Apparently, free gas clouds can only be induced to detonate by a sufficiently strong detonative initiation. Independently from the initiating event (deflagration, detonation) in the practice of damage analysis it has become customary to describe the consequences of an explosion event by means of the so-called TNT-equivalent. Therefore, it is attempted to specify this equivalent for hydrocarbons by means of energetic considerations including the propagation functions for the case of spherically symmetric detonations. In correspondence with U.S. recommendations it follows that with regard to the effects, 1 kg of hydrocarbon could be equated to about 1 kg TNT. In analogous manner to the safety distances required in the handling and storage of high-explosives a mass-distance relation of the form R = k x Lsup(1/3) could be considered, where L is the mass of spontaneously released hydrocarbon and k varies only with the structural shape of the blast loaded buildings. (orig./HP)

  10. Evaluation of blast-induced vibration effects on structures 1

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Rim; Jeon, Gyu Shick; Lee, Dae Soo; Joo, Kwang Ho; Lee, Woong Keon [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of); Ryu, Chang Ha; Chung, So Keul; Lee, Kyung Won; Shin, Hee Soon; Chun, Sun Woo; Park, Yeon Jun; Synn, Joong Ho; Choi, Byung Hee [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-31

    Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants to maintain the safety of structures and facilities in power plants. Our own standard for safety level of blast vibration is not prepared yet, and foreign standards have been generally employed without theoretical and experimental verification. Safety-related structures of power plants and facilities have to be protected against the effects of possible hazards due to blast vibration. Earthquakes have been considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibration are not. In order to ensure the safety, rational safe criterion should be established and blast design should be satisfy it, which requires the development of a model for prediction of vibration level through more systematic measurement and analysis. The main objectives of the study are : to provide background data for establishing the rational safe vibration limits, to develop models for prediction of blast vibration level, to establish safe blast design criterion, and to accumulate techniques for field measurements, data acquisition and analysis (author). 80 refs., 347 figs.

  11. Analysis of the blasting effect on the electric shove loading efficiency of the open pit

    Institute of Scientific and Technical Information of China (English)

    FU Tian-guang; SUN Ying

    2008-01-01

    The connection between blasting cost and comprehensive cost is the main concern.Some blasting effect factors (such as unit explosive consumption,uniformity of blockness,shape and porosity of blasting heap),which had an influence on electric shove loading efficiency,were analyzed.In the end a project to properly increase in blasting cost to decrease the comprehensive cost was put forward.At the same time,the hole-by-hole blasting is effective technology to improve blasting effect.

  12. Mitigation of Blast Effects on Aluminum Foam Protected Masonry Walls

    Institute of Scientific and Technical Information of China (English)

    SU Yu; WU Chengqing; GRIFFITH Mike

    2008-01-01

    Terrorist attacks using improvised explosive devices (lED) can result in unreinforced masonry (URM) wall collapse.Protecting URM wall from lED attack is very complicated.An effective solution to mitigate blast effects on URM wall is to retrofit URM walls with metallic foam sheets to absorb blast energy.However,mitigation of blast effects on metallic foam protected URM walls is currently in their infancy in the world.In this palaer,numerical models are used to simulate the performance of aluminum foam protected URM walls subjected to blast loads.A distinctive model,in which mortar and brick units of masonry are discritized individually,is used to model the performance of masonry and the contact between the masonry and steel face-sheet of aluminum foam is modelled using the interface element model.The aluminum foam is modelled by a nonlinear elastoplastic material model.The material models for masonry,aluminum foam and interface are then coded into a finite element program LS-DYNA3D to perform the numerical calculations of response and damage of aluminum foam protected URM walls under airblast loads.Discussion is made on the effectiveness of the aluminum foam protected system for URM wall against blast loads.

  13. Modelling Blast Effects on a Reinforced Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Markellos Andreou

    2016-01-01

    Full Text Available The detailed investigation of blast phenomena and their catastrophic effects on existing structures are the main objectives of the present paper. It is well known that blast phenomena may be characterized by significant complexity, often involving complicated wave propagation effects as well as distinguishable material behaviors. Considering the above and in an attempt to provide a simplified modelling approach for the simulation of blast effects, a novel procedure is presented herein based on well-established methodologies and common engineering practices. In the above framework, firstly, the “predominant” deformation shape of the structure is estimated based on elastic finite element simulations under blast loads and then the structural response of the system is evaluated as a result of common computational beam-element tools such as displacement-based pushover analysis. The proposed methodology provides an immediate first estimation of the structural behavior under blast loads, based on familiar engineering procedures. A two-span reinforced concrete bridge was thoroughly investigated and the results provide insightful information regarding the damage patterns and localization.

  14. Effect of the Location of the Detonation Initiation Point for Bench Blasting

    OpenAIRE

    Liang Liu; Ming Chen; Wenbo Lu; Yingguo Hu; Zhendong Leng

    2015-01-01

    Uneven floor and fragmentation play an important role in blasting operations due to the direct effects on the efficiency of hauling and loading. This paper focuses on the influences of initiation position on bench blasting in order to improve blasting effects. The numerical simulations of bench blasting at different initiation points (top, middle, and bottom) are implemented based on secondary development of LS-DYNA with a tensile-compressive damage model. The damage spatial distribution char...

  15. Strain Rate Effects in CFRP Used For Blast Mitigation

    Directory of Open Access Journals (Sweden)

    Sarah. L. Orton

    2014-04-01

    Full Text Available The purpose of this research is to gain a better understanding of strain rate effects in carbon fiber reinforced polymer (CFRP laminates exposed to blast loading. The use of CFRP offers an attractive option for mitigating structures exposed to blasts. However, the effect of high strain rates in CFRP composites commonly used in the civil industry is unknown. This research conducted tensile tests of 21 CFRP coupons using a hydraulically powered dynamic loader. The strain rates ranged from 0.0015 s−1 to 7.86 s−1 and are representative of strain rates that CFRP may see in a blast when used to strengthen reinforced concrete structures. The results of the testing showed no increase in the tensile strength or stiffness of the CFRP at the higher strain rates. In addition, the results showed significant scatter in the tensile strengths possibly due to the rate of loading or manufacture of the coupon.

  16. Effect Of Sand Blasting On Soda Lime Glass Properties

    OpenAIRE

    Bousbaa, C.; Madjoubi, M. A.; Hamidouche, Z; N. BOUAOUADJA

    2003-01-01

    The present work is based on a simulation in laboratory of the erosion of a soda lime glass caused by sand blasting during sandstorms. It deals with the effects of sand blasting duration (from 0 to 60 min) and impact angle (from 0 to 90°) on the material and its properties. The principal erosion characteristics and properties of the material studied are the mass loss, the erosion rate, the surface roughness, the optical transmission and the mechanical strength. The influence of the optical tr...

  17. Underground shelters for protection against blast and radiation effects

    International Nuclear Information System (INIS)

    Underground shelters are generally designed and developed for the protection of personnel, arms and ammunitions, equipment and other materials against direct effects of nuclear explosion like blast, nuclear radiation, thermal radiation etc. Lightweight underground shelters made of thin mild steel corrugated sheets in cylindrical and hairpin shapes are developed for the protection of civil population and defence purpose. Each part of these shelters can be easily carried by man and can be assembled in short period by special fasteners. These shelters are designed for 1.5 m of earth pressure, peak blast overpressure and nuclear radiations produced by a nuclear blast. These shelters are analysed using a finite element package called ANSYS. The effect of soil -structure interaction is considered by using four values of modulus of sub-grade reaction. These shelters are analysed for static and transient loading, modal and buckling analyses. Maximum stresses and deflections, natural frequencies, mode shapes, buckling load factors and buckled mode shapes are found out and are presented in this paper. Limited simulated trials are also conducted to find out the suitability of these shelters against the blast and nuclear radiation effects in the field conditions and their results are also presented in this paper. (author)

  18. Measurements of near-field blast effects using kinetic plates

    International Nuclear Information System (INIS)

    Few tests have been designed to measure the near-field blast impulse of ideal and non-ideal explosives, mostly because of the inherent experimental difficulties due to non-transparent fireballs and thermal effects on gauges. In order to measure blast impulse in the near-field, a new test has been developed by firing spherical charges at 152 mm (6 in) from steel plates and probing acceleration using laser velocimetry. Tests measure the velocity imparted to the steel plate in the 50 – 300 μs timeframe, and are compared with free-field overpressure measurements at 1.52 m (5 ft) and ms timescales using piezoelectric pencil gauges. Specifically, tests have been performed with C4 to probe the contributions of ideal explosives and charge size effects. Non-ideal aluminized explosive formulations have been studied to explore the role of aluminum in near-field blast effects and far-field pressure, and are compared with formulations using LiF as an inert surrogate replacement for Al. The results are compared with other near-field blast tests and cylinder tests, and the validity of this test is explored with modeling and basic theory.

  19. Effect of Foam Cladding for Blast Mitigation: Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    MA Guowei; YE Ziqing; ZHANG Xingui

    2006-01-01

    Two numerical simulations were performed to investigate the protective effect of the foam cladding.One simulation is based on a previous experimental study,which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading.The other model is a steel beam with and without a foam cladding under blast loading.The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian (ALE)coupling model.The first approach is relatively simple and widely used.The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid.Itis found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum.However,the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding.It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure.

  20. Effect of casing yield stress on bomb blast impulse

    Directory of Open Access Journals (Sweden)

    Hutchinson M.D.

    2012-08-01

    Full Text Available An equation to predict blast effects from cased charges was first proposed by U. Fano in 1944 and revised by E.M. Fisher in 1953 [1]. Fisher’s revision provides much better matches to available blast impulse data, but still requires empirical parameter adjustments. A new derivation [2], based on the work of R.W. Gurney [3] and G.I. Taylor [4], has resulted in an equation which nearly matches experimental data. This new analytical model is also capable of being extended, through the incorporation of additional physics, such as the effects of early case fracture, finite casing thickness, casing metal strain energy dissipation, explosive gas escape through casing fractures and the comparative dynamics of blast wave and metal fragment impacts. This paper will focus on the choice of relevant case fracture strain criterion, as it will be shown that this allows the explicit inclusion of the dynamic properties of the explosive and casing metal. It will include a review and critique of the most significant earlier work on this topic, contained in a paper by Hoggatt and Recht [5]. Using this extended analytical model, good matches can readily be made to available free-field blast impulse data, without any empirical adjustments being needed. Further work will be required to apply this model to aluminised and other highly oxygen-deficient explosives.

  1. Detailed Comparison of Blast Effects in Air and Vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Tringe, J W; Molitoris, J D; Garza, R G; Andreski, H G; Batteux, J D; Lauderbach, L M; Vincent, E R; Wong, B M

    2007-07-26

    Although blast mitigation is most often achieved with solid shielding, ambient gas pressure can also affect the coupling of shock waves to solid targets. In this work the role of air as an energy transfer medium was examined experimentally by subjecting identical large-area rectangular witness plates to short-range blast effects in air and vacuum ({approx}50 mtorr) at 25 C. The expanding reactant front of 3 kg C4 charges was observed by fast camera to be cylindrically symmetric in both air and vacuum. The horizontal component of the reactant cloud velocity (perpendicular to the witness plates) was constant in both cases, with values of 3.0 and 5.9 km/s for air and vacuum, respectively. As a result of the blast, witness plates were plastically deformed into a shallow dish geometry, with local maxima 30 and 20 mm deep for air and vacuum, respectively. The average plate deflection from the air blast was 11 mm, {approx}10% deeper than the average vacuum plate deflection. Shock pressure estimates were made with a simple impedance-matching model, and indicate peak values in the 30-50 MPa range are consistent with the reactant cloud density and velocity. However, more detailed analysis is necessary to definitely establish the mechanisms by which air couples shock energy to the plates.

  2. Effects of scale on internal blast measurements

    International Nuclear Information System (INIS)

    This paper presents a comparative study between large and small-scale internal blast experiments with the goal of using the small-scale analog for energetic performance evaluation. In the small-scale experiment, highly confined explosive samples <0.5 g were subjected to the output from a PETN detonator while enclosed in a 3-liter chamber. Large-scale tests up to 23 kg were unconfined and released in a chamber with a factor of 60,000 increase in volume. The comparative metric in these experiments is peak quasi-static overpressure, with the explosive sample expressed as sample energy/chamber volume, which normalizes measured pressures across scale. Small-scale measured pressures were always lower than the large-scale measurements, because of heat-loss to the high confinement inherent in the small-scale apparatus. This heat-loss can be quantified and used to correct the small-scale pressure measurements. In some cases the heat-loss was large enough to quench reaction of lower energy samples. These results suggest that small-scale internal blast tests do correlate with their large-scale counterparts, provided that heat-loss to confinement can be measured, and that less reactive or lower energy samples are not quenched by heat-loss.

  3. A Review of Current Researches on Blast Load Effects on Building Structures in China

    Institute of Scientific and Technical Information of China (English)

    LI Zhongxian; DU Hao; BAO Chunxiao

    2006-01-01

    The damages of building structures subjected to multifarious explosions cause huge losses of lives and property.It is the reason why the blast resistance and explosion protection of building structures become an important research topic in the civil engineering field all over the world.This paper provides an overview of the research work in China on blast loads effect on building structures.It includes modeling blast shock wave propagation and their effects,the dynamic responses of various building structures under blast loads and the measures to strengthen the building structures against blast loads.The paper also discusses the achievements and further work that needs be done for a better understanding of the blast loads' effects on building structures,and for deriving effective and economic techniques to design new or to strengthen existing structures.

  4. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2014-01-01

    Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

  5. Effect of coke strength on blast furnace performance

    Energy Technology Data Exchange (ETDEWEB)

    Belyshov, V.N.; Emushintsev, V.V.; Minikes, E.E.; Tsymbal, G.L.; Vakulin, V.N.

    1985-09-01

    The authors report on results of a study, conducted from 1979 to 1982, analyzing the effect of the strength of commercially produced coke on furnace performance, for furnaces of different volumes. The effect of coke strength on blast-furnace performance was analyzed in two directions: determination of the dependence of coke loss from fragmentation on coke strength indices; evaluation of the effect of the coke strength on melting indices. It is found that high-strength coke is needed for large-volume furnaces and that reduction in coke strength helps cause tuyere burning.

  6. Effects of Controllable Blasting Variables on Number of Boulders Generated after Blasting in Ratcon and NSCE Quarries, Ibadan, Oyo State, Nigeria

    OpenAIRE

    Abiodun Ismail LAWAL; Akande Jide Muili

    2013-01-01

    The research work examines the effects of controllable blasting variables on number of boulders generated after blasting. The objective of the research was achieved through collection of data related to blasting which are drill hole depth, drill hole diameter, burden, spacing, average charge per hole, and specific charge. The collected data were analysed statistically using both Microsoft Excel Software and SPSS Software. The result of the analysis reveals that all the input controllable blas...

  7. Effects of low-level blast exposure on the nervous system: Is there really a controversy?

    Directory of Open Access Journals (Sweden)

    Gregory A Elder

    2014-12-01

    Full Text Available High-pressure blast waves can cause extensive CNS injury in humans. However, in combat settings such as Iraq and Afghanistan, lower level exposures associated with mild TBI (mTBI or subclinical exposure have been much more common. Yet controversy exists concerning what traits can be attributed to low-level blast, in large part due to the difficulty of distinguishing blast-related mTBI from post-traumatic stress disorder (PTSD. We describe how TBI is defined in humans and the problems posed in using current definitions to recognize blast-related mTBI. We next consider the problem of applying definitions of human mTBI to animal models, in particular that TBI severity in humans is defined in relation to alteration of consciousness at the time of injury, which typically cannot be assessed in animals. However, based on outcome assessments a condition of low-level blast exposure can be defined in animals that likely approximates human mTBI or subclinical exposure. We review blast injury modeling in animals noting that inconsistencies in experimental approach have contributed to uncertainty over the effects of low-level blast. Yet animal studies show that low-level blast pressure waves are transmitted to the brain. In brain low-level blast exposures cause behavioral, biochemical, pathological and physiological effects on the nervous system including the induction of PTSD-related behavioral traits in the absence of a psychological stressor. We review the relationship of blast exposure to chronic neurodegenerative diseases noting the paradoxical lowering of Abeta by blast, which along with other observations suggest that blast-related TBI is pathophysiologically distinct from non-blast TBI. Human neuroimaging studies show that blast-related mTBI is associated with a variety of chronic effects that are unlikely to be explained by co-morbid PTSD. We conclude that abundant evidence supports low-level blast as having long-term effects on the nervous system.

  8. Effect of the Location of the Detonation Initiation Point for Bench Blasting

    Directory of Open Access Journals (Sweden)

    Liang Liu

    2015-01-01

    Full Text Available Uneven floor and fragmentation play an important role in blasting operations due to the direct effects on the efficiency of hauling and loading. This paper focuses on the influences of initiation position on bench blasting in order to improve blasting effects. The numerical simulations of bench blasting at different initiation points (top, middle, and bottom are implemented based on secondary development of LS-DYNA with a tensile-compressive damage model. The damage spatial distribution characteristics of different initiation points are compared. The outlines of rock foundation and boulder areas are analyzed with the damage threshold of critical breakage that is ascertained by acoustic characteristic of damage rock mass. Results of the numerical simulations demonstrate that different initiation points make a great influence on the stress and energy distribution in blasting process and induce different blasting effects. Middle initiation turns out to be the best initiation to increase the flatness of the floor and decrease the oversize boulder ratio simultaneously, which will increase the damage areas of the bottom and top regions and give a better blasting effect. Field experiment in Baihetan Station was carried out to validate conclusions of numerical simulation. Research could provide a good reference for the improvement of rock blasting.

  9. Effects of repetitive low-pressure explosive blast on primary neurons and mixed cultures.

    Science.gov (United States)

    Zander, Nicole E; Piehler, Thuvan; Banton, Rohan; Benjamin, Richard

    2016-09-01

    Repetitive mild traumatic brain injury represents a considerable health concern, particularly for athletes and military personnel. For blast-induced brain injury, threshold shock-impulse levels required to induce such injuries and cumulative effects with single and/or multiple exposures are not well characterized. Currently, there is no established in vitro experimental model with blast pressure waves generated by live explosives. This study presents results of primary neurons and mixed cultures subjected to our unique in vitro indoor experimental platform that uses real military explosive charges to probe the effects of primary explosive blast at the cellular level. The effects of the blast on membrane permeability, generation of reactive oxygen species (ROS), uptake of sodium ions, intracellular calcium, and release of glutamate were probed 2 and 24 hr postblast. Significant changes in membrane permeability and sodium uptake among the sham, single-blast-injured, and triple-blast-injured samples were observed. A significant increase in ROS and glutamate release was observed for the triple-blast-injured samples compared with the sham. Changes in intracellular calcium were not significant. These results suggest that blast exposure disrupts the integrity of the plasma membrane, leading to the upset of ion homeostasis, formation of ROS, and glutamate release. Published 2016. †This article is a U.S. Government work and is in the public domain in the USA. PMID:27317559

  10. Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement

    Institute of Scientific and Technical Information of China (English)

    YAN Chang-bin

    2007-01-01

    The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation (0.8-1.2 m) was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, but the damage degree (D) increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers.

  11. EFFECTS OF BLAST-FURNACE SLAG ON NATURAL POZZOLAN-BASED GEOPOLYMER CEMENT

    OpenAIRE

    MAHSHAD YAZDANIPOUR; EBRAHIM NAJAFI KANI; ALI ALLAHVERDI

    2011-01-01

    A number of geopolymer cement mixes were designed and produced by alkali-activation of a pumice-type natural pozzolan. Effects of blast-furnace slag on basic engineering properties of the mixes were studied. Different engineering properties of the mixes such as setting times and 28-day compressive strength were studied at different amounts of blast-furnace slag, sodium oxide content, and water-to-cement ratio. The mix comprising of 5 wt.% blast-furnace slag and 8 wt.% Na2O with a water-to-dry...

  12. Literature survey of blast and fire effects of nuclear weapons on urban areas

    International Nuclear Information System (INIS)

    The American literature of the past 30 years on fire and blast effects of nuclear weapons on urban areas has been surveyed. The relevant work is briefly sketched and areas where information is apparently lacking are noted. This report is intended to provide the basis for suggesting research priorities in the fire and blast effects area for the Federal Emergency Management Agency. It is also intended to provide entry into the literature for researchers. over 850 references are given

  13. Literature survey of blast and fire effects of nuclear weapons on urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Reitter, T.A.; McCallen, D.B.; Kang, S.W.

    1982-06-01

    The American literature of the past 30 years on fire and blast effects of nuclear weapons on urban areas has been surveyed. The relevant work is briefly sketched and areas where information is apparently lacking are noted. This report is intended to provide the basis for suggesting research priorities in the fire and blast effects area for the Federal Emergency Management Agency. It is also intended to provide entry into the literature for researchers. over 850 references are given.

  14. Simplified method for the assessment of the blast effects on buildings

    OpenAIRE

    Pajntar, Tomaž

    2011-01-01

    Abstract: Improvised explosive devices are the most common terroristic weapons used nowadays in terroristic attacks. Human casualties are the main goals of terrorist attacks, and buildings where the people are gathering represent their primary goal. Blast in the vicinity of any structure may represent catastrophic event for any building by destroying its outer envelope and load bearing structural elements. Due to secondary effects such are debris, fire and smoke, risk due to blast effects ...

  15. Effects of Primary Blast Overpressure on Retina and Optic Tract in Rats

    Science.gov (United States)

    DeMar, James; Sharrow, Keith; Hill, Miya; Berman, Jonathan; Oliver, Thomas; Long, Joseph

    2016-01-01

    Blast has been the leading cause of injury, particularly traumatic brain injury and visual system injury, in combat operations in Iraq and Afghanistan. We determined the effect of shock tube-generated primary blast on retinal electrophysiology and on retinal and brain optic tract histopathology in a rat model. The amplitude of a- and b-waves on the electroretinogram (ERG) for both right and left eyes were measured prior to a battlefield simulation Friedlander-type blast wave and on 1, 7, and 14 days thereafter. Histopathologic findings of the right and left retina and the right and left optic tracts (2.8 mm postoptic chiasm) were evaluated 14 days after the blast. For two experiments in which the right eye was oriented to the blast, the amplitude of ERG a- and b-waves at 7 days post blast on the right side but not on the left side was diminished compared to that of sham animals (P = 0.005–0.01) Histopathologic injury scores at 14 days post blast for the right retina but not the left retina were higher than for sham animals (P = 0.01), and histopathologic injury scores at 14 days for both optic tracts were markedly higher than for shams (P blast wave, comparable to that causing human injury, produced injury to the retina as determined by ERG and histopathology, and to both postchiasmatic optic tracts as determined by histopathology. This model may be useful for analyzing the effect of therapeutic interventions on retinal damage due to primary blast waves. PMID:27199884

  16. Effects Of Primary Blast Overpressure On Retina And Optic Tract In Rats

    Directory of Open Access Journals (Sweden)

    James eDemar

    2016-04-01

    Full Text Available Blast has been the leading cause of injury, particularly traumatic brain injury and visual system injury, in combat operations in Iraq and Afghanistan. We determined the effect of shock tube-generated primary blast on retinal electrophysiology and on retinal and brain optic tract histopathology in a rat model.The amplitude of a- and b- waves on the electroretinogram (ERG for both right and left eyes were measured prior to a battlefield-simulation Friedlander-type blast wave and on 1, 7, and 14 days thereafter. Histopathologic findings of the right and left retina and the right and left optic tracts (2.8 mm post-optic chiasm were evaluated 14 days after the blast.For two experiments in which the right eye was oriented to the blast, the amplitude of ERG a- and b-waves at 7 days post-blast on the right side but not on the left side was diminished compared to that of sham animals (P=0.005-0.01 Histopathologic injury scores at 14 days post-blast for the right retina but not the left retina were higher than for sham animals (P=0.01, and histopathologic injury scores at 14 days for both optic tracts were markedly higher than for shams (P < 0.0001. Exposure of one eye to a blast wave, comparable to that causing human injury, produced injury to the retina as determined by ERG and histopathology, and to both post-chiasmatic optic tracts as determined by histopathology. This model may be useful for analyzing the effect of therapeutic interventions on retinal damage due to primary blast waves.

  17. Mesh Size Effect in Numerical Simulation of Blast Wave Propagation and Interaction with Structures

    Institute of Scientific and Technical Information of China (English)

    SHI Yanchao; LI Zhongxian; HAO Hong

    2008-01-01

    Numerical method is popular in analysing the blast wave propagation and interaction with structures.However, because of the extremely short duration of blast wave and energy transmission between different grids, the numerical results are sensitive to the finite element mesh size.Previous numerical simulations show that a mesh size acceptable to one blast scenario might not be proper for another case, even though the difference between the two scenarios is very small,indicating a simple numerical mesh size convergence test might not be enough to guarantee accurate numerical results.Therefore, both coarse mesh and fine mesh were used in different blast scenarios to investigate the mesh size effect on numerical results of blast wave propagation and interaction with structures.Based on the numerical results and their comparison with field test results and the design charts in TM5-1300, a numerical modification method was proposed to correct the influence of the mesh size on the simulated results.It can be easily used to improve the accuracy of the numerical results of blast wave propagation and blast loads on structures.

  18. Simultaneous investigation of blast induced ground vibration and airblast effects on safety level of structures and human in surface blasting

    Institute of Scientific and Technical Information of China (English)

    Faramarzi Farhad⇑; Ebrahimi Farsangi Mohammad Ali; Mansouri Hamid

    2014-01-01

    The significance of studying, monitoring and predicting blast induced vibration and noise level in mining and civil activities is justified in the capability of imposing damages, sense of uncertainty due to negative psychological impacts on involved personnel and also judicial complaints of local inhabitants in the nearby area. This paper presents achieved results during an investigation carried out at Sungun Copper Mine, Iran. Besides, the research also studied the significance of blast induced ground vibration and air-blast on safety aspects of nearby structures, potential risks, frequency analysis, and human response. According to the United States Bureau of Mines (USBM) standard, the attenuation equations were devel-oped using field records. A general frequency analysis and risk evaluation revealed that:94%of generated frequencies are less than 14 Hz which is within the natural frequency of structures that increases risk of damage. At the end, studies of human response showed destructive effects of the phenomena by ranging between 2.54 and 25.40 mm/s for ground vibrations and by the average value of 110 dB for noise levels which could increase sense of uncertainty among involved employees.

  19. Effects of Cultivar, Planting Period, and Fungicide Usage on Rice Blast Infection Levels and Crop Yield

    OpenAIRE

    Nasruddin, Andi

    2008-01-01

    Studies were separately conducted to determine the effects of cultivar, planting date, and fungicide usage on rice blast disease, caused by Pyricularia grisea (Cooke) Sacc. [= Magnaporthe grisea (Hebert) Barr] in Kecamatan Manggala, South Sulawesi Indonesia. The four rice varieties were IR-66, Cisantana, Cigeulis, and Filipin. The results showed that IR-66 was moderately resistant to leaf and neck blast, with the lowest percentage unfilled grains per panicle. Cisantana reacted mod...

  20. Effects of Cultivar, Planting Period, and Fungicide Usage on Rice Blast Infection Levels and Crop Yield

    OpenAIRE

    Andi, Nasruddin; Nur, Amin

    2013-01-01

    Studies were separately conducted to determine the effects of cultivar, planting date, and fungicide usage on rice blast disease, caused by Pyricularia grisea (Cooke) Sacc. [= Magnaporthe grisea (Hebert) Barr] in Kecamatan Manggala, South Sulawesi Indonesia. The four rice varieties were IR-66, Cisantana, Cigeulis, and Filipin. The results showed that IR-66 was moderately resistant to leaf and neck blast, with the lowest percentage unfilled grains per panicle. Cisantana reacted mod...

  1. Effect of shot peening and grit blasting on surface integrity: Influence on residual stresses

    Institute of Scientific and Technical Information of China (English)

    K.TOSHA; LU Jian

    2006-01-01

    The influences of factors such as particle size (0.55-2.2 mm), particle velocity (15-35 m/s) and thickness of work material on the surface integrity were investigated. The residual stresses induced by shot peening or grit blasting were examined. In order to clarify the influences of those factors on residual stress included in the surface integrity, a medium carbon steel (w(C)= 0.45%, 180 HV) was peened by a centrifugal type peening machine using cast steel particles (650-800 HV). The results show that the compressive residual stresses on the peened surface are larger than those of grit blasting; the critical thickness of shot peening is about 50% thicker than that of grit blasting; the high compressive stresses induced by blasting are owing to the wrought or peening effect.

  2. Assessment of blast effect open pit,”Ranci’’ of shock waves on constructed facilities and environment

    OpenAIRE

    Trajkovik, Slobodan; Lutovac, Suzana; Ravilik, Marija; Doneva, Nikolinka

    2013-01-01

    The blast effect problem of shock waves is growing in the area surrounding blasting activities. In addition to damage shock waves may cause on buildings and mining site facilities, they also impact badly human force there, namely the environment. Lately considerable research in the world has been dedicated to the examination and numeric modelling of this phenomenon. Specific standards have been established defining the blast effect margin level of shock waves on facilities and human force th...

  3. Assessment of Blasting Operations Effects During Highway Tunnel Construction

    OpenAIRE

    Valašková Veronika; Papán Daniel; Drusa Marián

    2015-01-01

    Blasting operations are one of the fundamental parts of daily civil engineering. Drilling and blasting still remain the only possible ways of tunnelling in very adverse geological conditions. However, this method is a source of various disadvantages, the main one being tremors propagating through the geological environment which not only affect buildings, but also disturb the comfort of living in the vicinity of the source. Designing this procedure is mostly done using standardized empirical ...

  4. Numerical study of water mitigation effects on blast wave

    Science.gov (United States)

    Cheng, M.; Hung, K. C.; Chong, O. Y.

    2005-11-01

    The mitigating effect of a water wall on the generation and propagation of blast waves of a nearby explosive has been investigated using a numerical approach. A multimaterial Eulerian finite element technique is used to study the influence of the design parameters, such as the water-to-explosive weight ratio, the water wall thickness, the air-gap and the cover area ratio of water on the effectiveness of the water mitigation concept. In the computational model, the detonation gases are modelled with the standard Jones Wilkins Lee (JWL) equation of state. Water, on the other hand, is treated as a compressible fluid with the Mie Gruneisen equation of state model. The validity of the computational model is checked against a limited amount of available experimental data, and the influence of mesh sizes on the convergence of results is also discussed. From the results of the extensive numerical experiments, it is deduced that firstly, the presence of an air-gap reduces the effectiveness of the water mitigator. Secondly, the higher the water-to-explosive weight ratio, the more significant is the reduction in peak pressure of the explosion. Typically, water-to-explosive weight ratios in the range of 1 3 are found to be most practical.

  5. Effects of Controllable Blasting Variables on Number of Boulders Generated after Blasting in Ratcon and NSCE Quarries, Ibadan, Oyo State, Nigeria

    Directory of Open Access Journals (Sweden)

    Abiodun Ismail LAWAL

    2013-03-01

    Full Text Available The research work examines the effects of controllable blasting variables on number of boulders generated after blasting. The objective of the research was achieved through collection of data related to blasting which are drill hole depth, drill hole diameter, burden, spacing, average charge per hole, and specific charge. The collected data were analysed statistically using both Microsoft Excel Software and SPSS Software. The result of the analysis reveals that all the input controllable blasting variables which are drill hole diameter (X1, drill hole depth (X2, hole spacing (X3, burden (X4, average charge per hole (X5, specific charge(X6 that participated as independent variables in the models are found to be significant and the R2 values obtained from the graph show a very strong correlation between the number of boulders generated after blasting and the input variables except that of drill hole diameter which shows a very weak correlation. The equation generated using the SPSS could be used to determine number of boulders generated after blasting.

  6. Modeling and Simulating Blast Effects on Electric Substations

    Energy Technology Data Exchange (ETDEWEB)

    Lyle G. Roybal; Robert F. Jeffers; Kent E. McGillivary; Tony D. Paul; Ryan Jacobson

    2009-05-01

    A software simulation tool was developed at the Idaho National Laboratory to estimate the fragility of electric substation components subject to an explosive blast. Damage caused by explosively driven fragments on a generic electric substation was estimated by using a ray-tracing technique to track and tabulate fragment impacts and penetrations of substation components. This technique is based on methods used for assessing vulnerability of military aircraft and ground vehicles to explosive blasts. An open-source rendering and ray-trace engine was used for geometric modeling and interactions between fragments and substation components. Semi-empirical material interactions models were used to calculate blast parameters and simulate high-velocity material interactions between explosively driven fragments and substation components. Finally, a Monte Carlo simulation was added to model the random nature of fragment generation allowing a skilled analyst to predict failure probabilities of substation components.

  7. Blasting Effects in Relation With Costs and Type of Exposives

    OpenAIRE

    Dambov, Risto; Stefanov, Mile; Dambov, Ilija

    2011-01-01

    Blasting is the basic operation in open pit mines in obtaining hard rock masses and has an important influence on the costs in the obtaining useful mineral raw material. The costs vary widely depending on the capacity of the open pit operation, the organisation, the machinery used as well as the professional support. The major goal of every professional man deployed in the process of blasting is to bring costs down to a minimum or to set and define parameters. The paper offers ana...

  8. U.S. regulatory requirements for blast effects from accidental explosions

    International Nuclear Information System (INIS)

    This paper is limited to accidental explosions external to nuclear power plants. Procedures for deciding if the risk of damage due to an accidental explosion is sufficiently high to warrant detailed study and methods for assessing structural capability when detailed study is needed are described. The dynamic blast load effect may be estimated by a simplified static procedure. The regulatory staff permits use of a dynamic load factor of 2 applied to the overpressure or reflected pressure, as appropriate, and the assumption that structures and structural elements will deform dynamically as though the loads were applied statically. This assumption allows the designer to compute stresses, moments and shears without reference to the distribution of inertial forces within the structure. Blast pressure should be considered to act both inward and outward to account for dynamic stress reversal. Overturning and sliding stability as well as the ability of supporting structures to carry loads transmitted from the directly loaded exterior surfaces must be assessed. A detailed dynamic analysis in which force-time histories and the stiffness and mass properties of the structures are employed is also acceptable. Damping is not important for air blast effects. The regulatory staff requires that blast effects be resisted elastically. This is consistent with regulatory philosophy that global loading situations should not be permitted to cause global damage. Appendix C to ACI-349, 'Code Requirements for Nuclear Safety Related Concrete Structures', in conflict with regulatory requirements, permits a ductility of 3 for blast loadings

  9. Assessment of the Effect of Blast Hole Diameter on the Number of Oversize Boulders Using ANN Model

    Science.gov (United States)

    Dhekne, Prakash; Pradhan, Manoj; Jade, Ravi Krishnarao

    2016-04-01

    Now-a-days, blasts are planned using large diameter blast holes. The loading density (kg/m) and subsequently the energy available for the breakage of the rockmass increase with the diameter. The in-hole velocity of detonation (VoD) of non-ideal explosive also boosts up with the increase in diameter till the optimum diameter is reached. The increase in the energy content and in-hole VoD cause a sizable effect on the rock fragmentation. The effect can be assessed by counting the number of oversize boulders. This paper explains as to how the technique of artificial neural network modeling was used to predict the number of oversize boulders resulting from ANFO and SME blasts with blast holes of different diameters. The results from ANFO blasts indicated that there was no significant variation in the number of oversize boulders with the diameter whereas a perceptible variation was noticed in case of SME blasts with the change in the diameter. The change in the number of oversize boulders in ANFO blasts was negligible because mean energy factor remained almost same even when the diameter of the blast holes was altered. The decrease in the number of oversize boulders in SME blasts was on account of increase in mean energy factor when the blast hole diameter was increased. The increase in the in-hole VoD due to increase in the diameter of the hole was not found to have an effect on the generation of oversize boulders as this increase was not substantial both in SME and ANFO blasts.

  10. Numerical simulations of near-field blast effects using kinetic plates

    International Nuclear Information System (INIS)

    Numerical simulations using two hydrocodes were compared to near-field measurements of blast impulse associated with ideal and non-ideal explosives to gain insight into testing results and predict untested configurations. The recently developed kinetic plate test was designed to measure blast impulse in the near-field by firing spherical charges in close range from steel plates and probing plate acceleration using laser velocimetry. Plate velocities for ideal, non-ideal and aluminized explosives tests were modeled using a three dimensional hydrocode. The effects of inert additives in the explosive formulation were modeled using a 1-D hydrocode with multiphase flow capability using Lagrangian particles. The relative effect of particle impact on the plate compared to the blast wave impulse is determined and modeling is compared to free field pressure results.

  11. EFFECTS OF BLAST-FURNACE SLAG ON NATURAL POZZOLAN-BASED GEOPOLYMER CEMENT

    Directory of Open Access Journals (Sweden)

    MAHSHAD YAZDANIPOUR

    2011-03-01

    Full Text Available A number of geopolymer cement mixes were designed and produced by alkali-activation of a pumice-type natural pozzolan. Effects of blast-furnace slag on basic engineering properties of the mixes were studied. Different engineering properties of the mixes such as setting times and 28-day compressive strength were studied at different amounts of blast-furnace slag, sodium oxide content, and water-to-cement ratio. The mix comprising of 5 wt.% blast-furnace slag and 8 wt.% Na2O with a water-to-dry binder ratio of 0.30 exhibits the highest 28-day compressive strength, i.e. 36 MPa. Mixes containing 5 wt.% of ground granulated blast furnace slag showed the least efflorescence or best soundness. Laboratory techniques of X-ray diffractometry (XRD, fourier transform infrared spectroscopy (FTIR, and scanning electron microscopy (SEM were utilized for characterizing a number of mixes and studying their molecular and micro-structure. Investigations done by scanning electron microscopy confirm that smaller blast-furnace slag particles react totally while the larger ones react partially with alkaline activators and contribute to the formation of a composite microstructure.

  12. Brittleness and Packing Density Effects on Blast-hole Cuttings Yield of Selected Rocks

    Directory of Open Access Journals (Sweden)

    B. Adebayo

    2016-06-01

    Full Text Available This paper evaluates brittleness and packing density to analysis their effects on blast-hole cutting yield for three selected rocks in Nigeria. Brittleness test (S20 was carried out in accordance with Norwegian Soil and Rock Engineering and the Brittleness Index (BI for the selected rocks were estimated. The packing density determined from the photomicrograph of the rock samples. The grain size of 45 blast-holes drill cuttings collected from three selected while drilling of these rocks were determined using standard method of America Society for Testing and Materials (ASTM D 2487. The brittleness values are 50%, 44% and 42% for micro granite, porphyritic granite and medium biotite granite respectively. The result of BI varied from 10.32 – 11.59 and they are rated as moderately brittle rocks. The values of packing density varied from 92.20 – 94.55%, 91.00 -92.96% and 92.92 – 94.96% for all the rocks. The maximum weights of blast-hole particle size retained at 75 µm are 106.00g, 103.28 g and 99.76 g for medium biotite granite, micro granite and porhyritic granite respectively. Packing density values have correlation to some extent with (S20 values hence, this influence the yield of blast-hole cuttings as drilling progresses. The minimum weight of blast-hole cuttings particle size retained at 150 µm agrees with brittleness index classification for micro granite.

  13. Effect Blasting Excavation of Yujiapeng Tunnel on Stability of Nearby Giant Dangerous Rock Masses (DRM)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of the interpretation of engineering geology of the tunnel and of its adjacent dangerous rock masses (DRM), this paper presents the energy and vibration parameters of the explosion that propagates in different blasting modes according to the experimental formulas now usually employed. Then the stability checking computation of T8-T12 area, the most dangerous area of DRM, is conducted under the limited blasting condition and with the limited equilibrium method. The result shows that the effect on the stability is only 5.5 % and that this area also contains certain safety reserves.

  14. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects.

    Science.gov (United States)

    Courtney, Amy C; Andrusiv, Lubov P; Courtney, Michael W

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile. PMID:22559580

  15. Tuyere development as an effective measure for high PC rate operation of blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Tagawa, T.; Kasai, A.; Nozawa, K.; Shibata, K. [Kobe Steel Ltd., Kakogawa Works, Hyogo (Japan). Ironmaking Dept.

    2008-07-01

    Kobe Steel has developed technologies to reduce coke consumption in its blast furnaces by injecting coal at a high rate. This paper described a newly developed tuyere and its contribution to improving permeability under high pulverized coal (PC) rate conditions at the blast furnaces at Kakogawa Works. Reducing the coke rate while increasing the coal injection rate results in higher ore/coke at the center region of the furnace, resulting in excessive peripheral gas and inducing gas channeling. Central coke charging (CCC) helps attain a stable gas flow inside the furnace by forming a vertical gas passage in the coke column. It enables furnace operators to directly control or enhance the central gas flow and improves gas and liquid permeability in the furnace bottom. In a conventional tuyere, the PC is introduced in or before the converged blast flow inside the tuyere where coal fines begin to decompose and interact with hot blasts. This newly developed convergent and divergent (CD) type tuyere was instrumental in safely reducing the pressure drop and its variation to a tolerable level even under ultra-high PCR conditions over 250 kg/thm. This paper described the effects of tuyere structure on raceway shapes using 3 types of tuyeres in a coke packed test furnace. It was concluded that the CD tuyere reduces pressure drop at the tuyere. An increase in PC rate offers benefits in terms of furnace stability. The CD tuyere also reduces coke deterioration in the raceway. 7 refs., 8 figs.

  16. Effect of Blast-Induced Vibration from New Railway Tunnel on Existing Adjacent Railway Tunnel in Xinjiang, China

    Science.gov (United States)

    Liang, Qingguo; Li, Jie; Li, Dewu; Ou, Erfeng

    2013-01-01

    The vibrations of existing service tunnels induced by blast-excavation of adjacent tunnels have attracted much attention from both academics and engineers during recent decades in China. The blasting vibration velocity (BVV) is the most widely used controlling index for in situ monitoring and safety assessment of existing lining structures. Although numerous in situ tests and simulations had been carried out to investigate blast-induced vibrations of existing tunnels due to excavation of new tunnels (mostly by bench excavation method), research on the overall dynamical response of existing service tunnels in terms of not only BVV but also stress/strain seemed limited for new tunnels excavated by the full-section blasting method. In this paper, the impacts of blast-induced vibrations from a new tunnel on an existing railway tunnel in Xinjiang, China were comprehensively investigated by using laboratory tests, in situ monitoring and numerical simulations. The measured data from laboratory tests and in situ monitoring were used to determine the parameters needed for numerical simulations, and were compared with the calculated results. Based on the results from in situ monitoring and numerical simulations, which were consistent with each other, the original blasting design and corresponding parameters were adjusted to reduce the maximum BVV, which proved to be effective and safe. The effect of both the static stress before blasting vibrations and the dynamic stress induced by blasting on the total stresses in the existing tunnel lining is also discussed. The methods and related results presented could be applied in projects with similar ground and distance between old and new tunnels if the new tunnel is to be excavated by the full-section blasting method.

  17. Blast-Induced Damage on Millisecond Blasting Model Test with Multicircle Vertical Blastholes

    OpenAIRE

    Qin-yong Ma; Pu Yuan; Jing-shuang Zhang; Rui-qiu Ma; Bo Han

    2015-01-01

    To investigate the blast-induced damage effect on surrounding rock in vertical shaft excavation, 4 kinds of millisecond blasting model tests with three-circle blastholes were designed and carried out with excavation blasting in vertical shaft as the background. The longitudinal wave velocity on the side of concrete model was also measured before and after blasting. Then blast damage factor was then calculated by measuring longitudinal wave velocity before and after blasting. The test results ...

  18. Effect of N level on rice yield, nitrogen accumulation and rice blast occurrence under rice intercropping system

    OpenAIRE

    Tang, Li; Lu, Guoli; Cu, Yiou; Zhang, Chaochun; Zhang, Fusuo; Zheng, Yi

    2009-01-01

    Abstract: Plant N nutrition plays an important role on plant metabolisms and crop diseases resistance. Intercropping can increase grain yields greatly and provide an ecological approach to disease control. Field trails of using two rice varieties with different resistance to rice blast, Huangkenuo (HKN) and Hexi-41(HX41), was carried out to investigate the effect of nitrogen fertilizer rate on rice yield, nitrogen accumulation and rice blast occurrence under rice mono-cropping and intercroppi...

  19. The integrated blast effects sensor suite: a rapidly developed, complex, system of systems.

    Science.gov (United States)

    Liu, Brian; Medda, Alessio; Woods, Douglas; Phelps, Shean; Fain, Walter

    2015-03-01

    Spurned by the increasing concern and consciousness of traumatic brain injuries in deployed U.S. service members, the U.S. Army Rapid Equipping Force sought help from the Georgia Tech Research Institute to rapidly develop and deploy a system capable of gathering relevant soldier-centric data-the Integrated Blast Effects Sensor Suite. To meet aggressive program milestones and requirements, Georgia Tech Research Institute engaged in rapid systems engineering efforts focused on leveraging iterative development and test methodologies. Ultimately, an integrated system of systems composed of vehicle systems, soldier-worn headset and torso systems, and data retrieval systems was deployed to troops in Afghanistan for an operational assessment. The Integrated Blast Effects Sensor Suite development process and parallel efforts investigating injury dosimetry methodologies have yielded unique findings and lessons learned, which should be incorporated into future evolutions of similar systems. PMID:25747653

  20. Calculation of wing response to gusts and blast waves with vortex lift effect

    Science.gov (United States)

    Chao, D. C.; Lan, C. E.

    1983-01-01

    A numerical study of the response of aircraft wings to atmospheric gusts and to nuclear explosions when flying at subsonic speeds is presented. The method is based upon unsteady quasi-vortex-lattice method, unsteady suction analogy, and Pade approximate. The calculated results, showing vortex lag effect, yield reasonable agreement with experimental data for incremental lift on wings in gust penetration and due to nuclear blast waves.

  1. THE EFFECT OF FISSURES IN DOLOMITE ROCK MASS ON BLASTING PROJECTS

    Directory of Open Access Journals (Sweden)

    Branko Božić

    1989-12-01

    Full Text Available Rock fractures in the form of fissures are one of more important geological features of a tectonic system. They have an effect on mechanical behaviour of rook masses exposed to the actions of surface forces. For exploitation in dolomite quarries carried out by blasting of deep shot holes it is important to know the system of fissures within a rock mass for the rock brakes along already weakened planes (the paper is published in Croatian.

  2. Influence of Strain-rate Effects on the Analysis of Steel Sections under Blast Loads

    OpenAIRE

    KARLOS VASILEIOS; SOLOMOS George

    2014-01-01

    The response of structural steel components under explosive loading is numerically investigated. First the procedure for determining the pressure loads to be applied on a structure after an explosion is briefly described. The importance of the material model and its capability of including the high strain-rate effects in the numerical analysis is studied by comparing simulations by the FEM code EUROPLEXUS with published data of real blast experiments. These comparisons are made with respect t...

  3. Rock fragmentation control in opencast blasting

    OpenAIRE

    Singh, P.K.; M P Roy; R.K. Paswan; Md. Sarim; Suraj Kumar; Rakesh Ranjan Jha

    2016-01-01

    The blasting operation plays a pivotal role in the overall economics of opencast mines. The blasting sub-system affects all the other associated sub-systems, i.e. loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity are the challenging tasks for practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, varying initiation practice in blast design and its effec...

  4. Research into the effect of surface mine blasting on buildings: long term monitoring projects

    Energy Technology Data Exchange (ETDEWEB)

    Farnfield, R.A.; White, T.J. (Leeds University, Leeds (United Kingdom). Blasting Research Group)

    1993-05-01

    The Blasting Research Group in the Department of Mining and Mineral Engineering at Leeds University is funded by British Coal Opencast to carry out research into various aspects of surface mine blasting. As part of this work the Group is investigating the possible effects of the approach of surface mining operations on various buildings. This paper describes the structural monitoring procedures, equipment and techniques employed. The wide range of parameters being monitored fall into three groups. (i) Parameters monitored every twenty minutes. (ii) Those monitored during or after each seismic event. (iii) Those monitored every four weeks. Each parameter is illustrated with data from Phase 1 of the research, where the mining operations are still remote from the buildings. 7 refs., 7 figs., 1 tab.

  5. Elastomeric Polymers for Retrofitting of Reinforced Concrete Structures against the Explosive Effects of Blast

    Directory of Open Access Journals (Sweden)

    S. N. Raman

    2012-01-01

    Full Text Available The main distinction of blast load from other types of dynamic loadings is its impulsive nature, where the loads usually act for a very short duration but transmit very high impulsive pressures. This paper presents an overview of the present retrofitting techniques in use to enhance the capacity of structural elements to withstand the effects of blast loads, and introduces an alternative retrofitting approach by utilizing polymer coatings. The authors have demonstrated the positive effects of this approach by conducting a numerical investigation on the behavior of an unretrofitted reinforced concrete panel subjected to the blast load from a 2 kg charge at 1.6 m stand-off distance, and subsequently comparing its performance with several polymer coated panels. The analysis was performed by using an explicit nonlinear finite element (FE code. The results demonstrate the contributions of this technique in terms of panel displacement control and energy dissipation. Considering that the polymer coating can also act as a protective layer in improving the durability of structural materials, this technique can also be optimized favorably to enhance the overall sustainability of structures.

  6. 30 CFR 780.13 - Operation plan: Blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Operation plan: Blasting. 780.13 Section 780.13... Operation plan: Blasting. (a) Blasting plan. Each application shall contain a blasting plan for the proposed... methods to be applied in controlling the adverse effects of blasting operations. (b) Monitoring...

  7. Effects of repetitive low-level blast exposure on visual systems and ocular structures

    Directory of Open Access Journals (Sweden)

    José E. Capó-Aponte, OD, PhD

    2015-06-01

    Full Text Available The purpose of this study was to determine whether repetitive exposure to low-level blasts during military breacher training produces acute and cumulative damage to the ocular tissues or visual system. The effects of low-level blast exposure on high-contrast visual acuity, contrast sensitivity, oculomotor function, color vision, visual field (VF, pupillary light reflex, corneal endothelial cell density (ECD, macular thickness, retinal nerve fiber layer thickness, and cup-to-disc ratio were assessed using a battery of standard clinical ophthalmic tests administered 10 times over a 2-year period. Data from nine male breacher instructors (Cadre were compared with data from four male breacher engineers (Control. The Cadre group showed higher vertical deviation at near than the Control group over time. The VF mean deviation on the left eye tended to be worse in the Cadre group throughout the study, suggesting a decrease in VF sensitivity (Cadre: –0.20 +/– 0.15 dB; Control: 1.05 +/– 0.15 dB; p = 0.03. The Cadre group had a reduced ECD (right eye: Cadre 2,478 cells/mm2 vs Control 2,808 cells/mm2, p = 0.02; left eye: Cadre 2,562 cells/mm2 vs Control 2,892 cells/mm2, p = 0.03. These results suggest that even low-level primary blast has the potential to produce occult eye injury.

  8. The effect of controlled microrobotized blasting on implant surface texturing and early osseointegration.

    Science.gov (United States)

    Gil, Luiz F; Marin, Charles; Teixeira, Hellen; Marão, Heloisa F; Tovar, Nick; Khan, Rehan; Bonfante, Estevam A; Janal, Malvin; Coelho, Paulo G

    2016-02-01

    Surface topography modifications have become a key strategy for hastening the host-to-implant response to implantable materials. The present study evaluated the effect of three different carefully controlled surface texture patterns achieved through microrobotized blasting (controlled to high, medium and low roughness) relative to a larger scale blasting procedure (control) in early osseointegration in a canine model. Four commercially pure grade 2 titanium alloy implants (one of each surface) were bilaterally placed in the radii of six beagle dogs and allowed end points of 1 and 6 weeks in vivo. Following sacrifice, implants in bone were non-decalcified processed for bone morphologic and histometric (bone-to-implant contact; bone area fraction occupancy) evaluation. Surface topography was characterized by scanning electron microscopy and optical interferometry. Results showed initial osteogenic tissue interaction at one week and new bone in intimate contact with all implant surfaces at 6 weeks. At 1 and 6 weeks in vivo, higher bone-to-implant and bone area fraction occupancy were observed for the high texture pattern microrobotized blasted surface relative to others. PMID:26508287

  9. Measurement of effective blast energy for direct initiation of spherical gaseous detonations from high-voltage spark discharge

    Science.gov (United States)

    Zhang, B.; Ng, H. D.; Lee, J. H. S.

    2012-01-01

    In this study, effective energy from spark discharge for direct blast initiation of spherical gaseous detonations is investigated. In the experiment, direct initiation of detonation is achieved via a spark discharge from a high-voltage and low-inductance capacitor bank and the spark energy is estimated from the analysis of the current output. To determine the blast wave energy from the powerful spark, the time-of-arrival of the blast wave in air is measured at different radii using a piezoelectric pressure transducer. Good agreement is found in the scaled blast trajectories, i.e., scaled time c o· t/ R o where c o is the ambient sound speed, as a function of blast radius R s/ R o between the numerical simulation of a spherical blast wave from a point energy source and the experimental results where the explosion length scale R o is computed using the equivalent spark energy from the first 1/4 current discharge cycle. Alternatively, by fitting the experimental trajectories data, the blast energy estimated from the numerical simulation appears also in good agreement with that obtained experimentally using the 1/4 cycle criterion. Using the 1/4 cycle of spark discharge for the effective energy, direct initiation experiments of spherical gaseous detonations are carried out to determine the critical initiation energy in C2H2-2.5O2 mixtures with 70 and 0% argon dilution. The experimental results obtained from the 1/4 cycle of spark discharge agree well with the prediction from two initiation models, namely, the Lee's surface energy model and a simplified work done model. The main source of discrepancy in the comparison can be explained by the uncertainty of cell size measurement which is needed for both the semi-empirical models.

  10. Effect of alkaline elements on the reactivity, strength and structural properties of blast furnace cokes

    Directory of Open Access Journals (Sweden)

    A. Bhattacharyya

    2015-07-01

    Full Text Available The present study concerns itself on the adverse effects of alkaline elements like sodium and potassium on blast furnace cokes. To achieve a deeper insight on the effects of alkaline elements on coke reactivity and strength, industrial coke samples impregnated with different alkaline species in various amounts have been tested under standard conditions to find out their Coke Reactivity Index (CRI and Coke Strength after Reaction (CSR values. Scanning electron microscopy, petrographic and Raman Spectrometric investigations demonstrate the change of structural properties. The mechanism of catalysis has been postulated.

  11. The effect of blast furnace coke quality on the possibility of its use

    OpenAIRE

    Konstanciak, A.

    2013-01-01

    In the paper behavior of the blast-furnace coke in the high temperature was presented. Comparative analysis of the chemical composition of the blast-furnace coke and the heat treatment of it were done. Coefficients M10 and M40 with the thermo-abrasiveness for chosen cokes were compared. The influence of ash content of the coke on the blast-furnace bed permeability was defined. Usefulness of the coke to blast-furnace process was also defined.

  12. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    OpenAIRE

    Hakan Yalciner

    2014-01-01

    Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single...

  13. A novel model for cost performance evaluation of pulverized coal injected into blast furnace based on effective calorific value

    Institute of Scientific and Technical Information of China (English)

    徐润生; 张建良; 左海滨; 李克江; 宋腾飞; 邵久刚

    2015-01-01

    The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.

  14. REDUCTION OF SEISMIC EFFECTS FROM BLASTING IN OPEN PIT COAL-MINES BANOVIĆI

    OpenAIRE

    Josip Krsnik; Zvonimir Ester; Vladimir Štimac

    1989-01-01

    The ground motions of higher intensities are generated by deep-hole blasting of overburden. The most appropriate type of explosive as well as the optimum parameters of blasting was chosen. The minor part of the blasting energy is being transformed into the kinetic energy of seismic waves of smaller intensity (the paper is published in Croatian).

  15. DYNAMIC LOAD ANALYSIS OF UNDERGROUND STRUCTURE UNDER EFFECT OF BLAST WAVE

    Institute of Scientific and Technical Information of China (English)

    REN Yun-yan; ZHANG Li; HAN Feng

    2006-01-01

    A semi-analytical method of solving the problem of dynamic stress concentration of arbitrary underground structure under the effect of blast waves was introduced.Using the Fourier transform theory, the shock waves (in the forms of SH-waves) can be converted into frequency bands. After employing complex functions and conformal mapping, the admittance functions of various underground structures were obtained. Then,the problem of the time domain dynamic stress response of underground structure can be easily solved through the Fourier inverse transform. At last, the results and curves of the dynamic stress for the square, triangle and horseshoe cavity were presented.

  16. Blast Valve Design and Related Studies : A Review

    OpenAIRE

    Sharma, P. K.; Patel, B. P.; Harbans Lal

    2016-01-01

    The protective structures required for performing critical operations are vulnerable to the blast and shock loads of advanced weapons. A blast valve is an important component of such structures for ventilation during normal conditions and for protection from blast/ shock during explosion. In this paper, various aspects of blast valve design and related studies are briefly reviewed. The concept and effects of blast wave, blast impact, numerical modelling and deformation of circular plate (one ...

  17. CONTROL OF FRAGMENTATION BY BLASTING

    Directory of Open Access Journals (Sweden)

    Branko Božić

    1998-12-01

    Full Text Available The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the quantity of explosive and its distribution within the rock mass. Over the last decade there have been considerable advances in our ability to measure and analyze blasting performance. These can now be combined with the continuing growth in computing power to develop a more effective description of rock fragmentation for use by future blasting practitioners. The paper describes a view of the fragmentation problem by blasting and the need for a new generation of engineering tools to guide the design and implementation of blasting operations.

  18. Effectiveness analysis of methane-drainage by deep-hole controlled pre-splitting blasting for preventing coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    CAO Shu-gang; LI Yong; LIU Yan-bao; ZHANG Li-qiang; XU A-meng

    2009-01-01

    In the study of the application effectiveness of deep-hole controlled pre-splitting blasting technology, it was found through laboratory micro test and field study on a mine in south China that under the technology, coal masses produce many irreversible cracks. Af-ter blasting, the nearer the distance from blasting hole, the larger the BET surface area and volume ratio of the infiltration pore are; they increased by 11.47% and 5.73%, respec-tively. The coefficient of air permeability is increased 4 times. After 3 months, the gas drainage rate was increased by 66%. In the first 15 days, the cumulative pumped gas was 1.93 times of blasting before. The average absolute gas emission decreased by 63.46%. Experimental results show that deep-hole controlled pre-splitting blasting not only prevents coal and gas outburst, but also gives good economic results.

  19. Thermal oxidation of medical Ti6Al4V blasted with ceramic particles: Effects on the microstructure, residual stresses and mechanical properties.

    Science.gov (United States)

    Lieblich, M; Barriuso, S; Multigner, M; González-Doncel, G; González-Carrasco, J L

    2016-02-01

    Roughening of Ti6Al4V by blasting with alumina or zirconia particles improves the mechanical fixation of implants by increasing the surface area available for bone/implant apposition. Additional thermal oxidation treatments of the blasted alloy have already shown to be a complementary low-cost solution to enhancing the in vitro biocompatibility and corrosion resistance of the alloy. In this work, the effects of oxidation treatment on a grit blasted Ti6Al4V biomedical alloy have been analysed in order to understand the net effect of the combined treatments on the alloy fatigue properties. Synchrotron radiation diffraction experiments have been performed to measure residual stresses before and after the treatments and microstructural and hardness changes have been determined. Although blasting of Ti6Al4V with small spherical zirconia particles increases the alloy fatigue resistance with respect to unblasted specimens, fatigue strength after oxidation decreases below the unblasted value, irrespective of the type of particle used for blasting. Moreover, at 700°C the as-blasted compressive residual stresses (700MPa) are not only fully relaxed but even moderate tensile residual stresses, of about 120MPa, are found beneath the blasted surfaces. Contrary to expectations, a moderate increase in hardness occurs towards the blasted surface after oxidation treatments. This can be attributed to the fact that grit blasting modifies the crystallographic texture of the Ti6Al4V shifting it to a random texture, which affects the hardness values as shown by additional experiments on cold rolled samples. The results indicate that the oxidation treatment performed to improve biocompatibility and corrosion resistance of grit blasted Ti6Al4V should be carried out with caution since the alloy fatigue strength can be critically diminished below the value required for high load-bearing components. PMID:26458115

  20. Effect of Shock Wave on Fabricated Anti-Blast Wall and Distribution Law Around the Wall Under Near Surface Explosion

    Institute of Scientific and Technical Information of China (English)

    WU Jun; LIU Jingbo; YAN Qiushi

    2008-01-01

    The loads of shock wave effect on fabricated anti-blast wall and distribution law around the wall were investigated by using near surface explosion test method and FEM.The pressure-time histories and variety law on the foreside and backside of the anti-blast wall were adopted in the tests of variety of different explosion distances and dynamites,as well as in the comparison between the test and numerical calculation.The test results show that the loads of shock wave effect on the anti-blast wall were essen-tially consistent with calculation results using criterion under surface explosion when explosion distances exceed 2 m,the distribution of overpressure behind wall was gained according to variety law based on small-large-small.It is also demonstrated that the peak overpressure behind wall had commonly appeared in wall height by 1.5--2.5 multiples,and the peak overpressures of protective building behind wall could be reduced effectively by using the fabricated anti-blast wall.

  1. Distance safety in blasting

    OpenAIRE

    Dambov, Risto; Karanakova Stefanovska, Radmila; Dambov, Ilija

    2015-01-01

    In blasting performance for any purpose and in any location to implement these safeguards is necessary first to determine (calculated) safety distances in terms of the effect of the explosion from some explosive quantity. Calculation of distance safety in blasting performance are refers to: calculation of safety distances from the influence of air - shock waves, calculation of safety distances (zones) of spraying pieces (fragments action) and calculation of safety distances in action of seis...

  2. The effect of blast furnace coke quality on the possibility of its use

    Directory of Open Access Journals (Sweden)

    A. Konstanciak

    2013-04-01

    Full Text Available In the paper behavior of the blast-furnace coke in the high temperature was presented. Comparative analysis of the chemical composition of the blast-furnace coke and the heat treatment of it were done. Coefficients M10 and M40 with the thermo-abrasiveness for chosen cokes were compared. The influence of ash content of the coke on the blast-furnace bed permeability was defined. Usefulness of the coke to blast-furnace process was also defined.

  3. Untangling the Effect of Head Acceleration on Brain Responses to Blast Waves.

    Science.gov (United States)

    Mao, Haojie; Unnikrishnan, Ginu; Rakesh, Vineet; Reifman, Jaques

    2015-12-01

    Multiple injury-causing mechanisms, such as wave propagation, skull flexure, cavitation, and head acceleration, have been proposed to explain blast-induced traumatic brain injury (bTBI). An accurate, quantitative description of the individual contribution of each of these mechanisms may be necessary to develop preventive strategies against bTBI. However, to date, despite numerous experimental and computational studies of bTBI, this question remains elusive. In this study, using a two-dimensional (2D) rat head model, we quantified the contribution of head acceleration to the biomechanical response of brain tissues when exposed to blast waves in a shock tube. We compared brain pressure at the coup, middle, and contre-coup regions between a 2D rat head model capable of simulating all mechanisms (i.e., the all-effects model) and an acceleration-only model. From our simulations, we determined that head acceleration contributed 36-45% of the maximum brain pressure at the coup region, had a negligible effect on the pressure at the middle region, and was responsible for the low pressure at the contre-coup region. Our findings also demonstrate that the current practice of measuring rat brain pressures close to the center of the brain would record only two-thirds of the maximum pressure observed at the coup region. Therefore, to accurately capture the effects of acceleration in experiments, we recommend placing a pressure sensor near the coup region, especially when investigating the acceleration mechanism using different experimental setups. PMID:26458125

  4. Chloroplast-Expressed MSI-99 in Tobacco Improves Disease Resistance and Displays Inhibitory Effect against Rice Blast Fungus

    Directory of Open Access Journals (Sweden)

    Yun-Peng Wang

    2015-03-01

    Full Text Available Rice blast is a major destructive fungal disease that poses a serious threat to rice production and the improvement of blast resistance is critical to rice breeding. The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. Transformed plants were obtained and verified to be homoplastomic by PCR and Southern hybridization. In planta assays demonstrated that the transgenic tobacco plants displayed an enhanced resistance to the fungal disease. The evaluation of the antimicrobial activity revealed that the crude protein extracts from the transgenic plants manifested an antimicrobial activity against E. coli, even after incubation at 120 °C for 20 min, indicating significant heat stability of MSI-99. More importantly, the MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

  5. Simulation of Blast Waves with Headwind

    Science.gov (United States)

    Olsen, Michael E.; Lawrence, Scott W.; Klopfer, Goetz H.; Mathias, Dovan; Onufer, Jeff T.

    2005-01-01

    The blast wave resulting from an explosion was simulated to provide guidance for models estimating risks for human spacecraft flight. Simulations included effects of headwind on blast propagation, Blasts were modelled as an initial value problem with a uniform high energy sphere expanding into an ambient field. Both still air and cases with headwind were calculated.

  6. BLEVE blast by expansion-controlled evaporation

    NARCIS (Netherlands)

    Berg, A.C. van den; Voort, M.M. van der; Weerheijm, J.; Versloot, N.H.A.

    2006-01-01

    This report presents a new method to calculate the blast effects originating from an exploding vessel of liquefied gas. Adequate blast calculation requires full knowledge of the blast source characteristics, that is, the release and subsequent evaporation rate of the flashing liquid. Because the con

  7. Blast furnace operation analysis by thermic exergy

    International Nuclear Information System (INIS)

    In order to know the blast furnace thermic state, the thermic exergy can be used, which considers the temperatures level of the process. The magnitude analysis of thermic exergy for blast furnace operation using pulverized coal, natural gas and oxygen injection by tuyeres, shows that natural gas injection is less effective than pulverized coal and enriched blast with oxygen simultaneous injection. (Author) 6 refs

  8. Effect of phase separation structure on cementitious reactivity of blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    LI Yu; SUN HengHu; LIU XiaoMing; CUI ZengDi

    2009-01-01

    Blast furnace slag samples with phase separation structure were prepared by re-melting and then water quenching process. By use of XRD, DTA and SEM technologies in combination with mechanical prop-erty experiment, the structure characteristics of samples were determined and their effects on cemen-titious reactivity were investigated. The results show that the samples with phase separation have better cementitious reactivity than sample with homogenous glass and sample with crystalline phases, which mainly contributes to its grass structure with coexistence of Ca-O rich phase and Si-O rich phase. Moreover, the amorphous samples possess hydrability which is affected by their formation process, since phase separation extends the range of possible Ca-rich crystalline phases.

  9. Effect of phase separation structure on cementitious reactivity of blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Blast furnace slag samples with phase separation structure were prepared by re-melting and then water quenching process. By use of XRD,DTA and SEM technologies in combination with mechanical property experiment,the structure characteristics of samples were determined and their effects on cementitious reactivity were investigated. The results show that the samples with phase separation have better cementitious reactivity than sample with homogenous glass and sample with crystalline phases,which mainly contributes to its glass structure with coexistence of Ca-O rich phase and Si-O rich phase. Moreover,the amorphous samples possess hydrability which is affected by their formation process,since phase separation extends the range of possible Ca-rich crystalline phases.

  10. Condition for Contur Blasting use on Openpit Mines

    OpenAIRE

    Krsmanovic, I; Dambov, Risto

    2010-01-01

    For purpose of obtaining a stable final slope in open pit mines practice, the most common approach is the contour blasting method and investigation of possible applications of various primary blasting methods for purpose of gaining the optimal techno-economical effects. This paper presents one of the contour blasting methods, drilling and blasting parameters, construction of explosive charges and method of initiation.

  11. Rock fragmentation control in opencast blasting

    Directory of Open Access Journals (Sweden)

    P.K. Singh

    2016-04-01

    Full Text Available The blasting operation plays a pivotal role in the overall economics of opencast mines. The blasting sub-system affects all the other associated sub-systems, i.e. loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity are the challenging tasks for practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, varying initiation practice in blast design and its effect on explosive energy release characteristic. This paper describes the result of a systematic study on the impact of blast design parameters on rock fragmentation at three mines in India. The mines use draglines and shovel–dumper combination for removal of overburden. Despite its pivotal role in controlling the overall economics of a mining operation, the expected blasting performance is often judged almost exclusively on the basis of poorly defined parameters such as powder factor and is often qualitative which results in very subjective assessment of blasting performance. Such an approach is very poor substitutes for accurate assessment of explosive and blasting performance. Ninety one blasts were conducted with varying blast designs and charging patterns, and their impacts on the rock fragmentation were documented. A high-speed camera was deployed to record the detonation sequences of the blasts. The efficiency of the loading machines was also correlated with the mean fragment size obtained from the fragmentation analyses.

  12. Assessment of blast loading effects - Types of explosion and loading effects

    International Nuclear Information System (INIS)

    There has been a great deal of work undertaken on the modelling and protection of the structure of buildings to explosive blast, fragment and missile penetration. Buildings and tunnels present interesting challenges because of the different energy release characteristics of modern explosives and gaseous mixtures. The paper describes how by combining modelling capabilities in blast-structure interaction with vulnerability models a capability is formed that has a wide range of potential uses, which links the many stages of response planning to an attack or more general emergency. From designing survivable infrastructures and planning protective measures, through training of staff and responders to handling of actual events, the concept provides a comprehensive approach to the whole spectrum of building and infrastructure survivability assessment issues for a wide range of environments. The paper describes its application to buildings and other related infrastructure.

  13. Blast-Induced Damage on Millisecond Blasting Model Test with Multicircle Vertical Blastholes

    Directory of Open Access Journals (Sweden)

    Qin-yong Ma

    2015-01-01

    Full Text Available To investigate the blast-induced damage effect on surrounding rock in vertical shaft excavation, 4 kinds of millisecond blasting model tests with three-circle blastholes were designed and carried out with excavation blasting in vertical shaft as the background. The longitudinal wave velocity on the side of concrete model was also measured before and after blasting. Then blast damage factor was then calculated by measuring longitudinal wave velocity before and after blasting. The test results show that the blast-induced damage factor attenuated gradually with the centre of three-circle blastholes as centre. With the threshold value of 0.19 for blast-induced damage factor, blast-induced damage zones for 4 kinds of model tests are described and there is an inverted cone blast-induced damage zone in concrete model. And analyses of cutting effect and blast-induced damage zone indicate that in order to minimize the blast-induced damage effect and ensure the cutting effect the reasonable blasting scheme for three-circle blastholes is the inner two-circle blastholes initiated simultaneously and the outer third circle blastholes initiated in a 25 ms delay.

  14. Synergic Effect of Shot Blasting and Deposit RE on Corrosion Behavior of TP304H steel in SO2-O2 at 923K

    Institute of Scientific and Technical Information of China (English)

    LI Xin-geng; FU Min; HE Ja-wen

    2004-01-01

    The corrosion behavior of TP304H steel with combined treatment of shot blasting and electrophoresis deposited RE coating in 1%SO2+14%O2+85%Ar mixture gaseous has been studied at 923K for 150 hours. The results show that both RE coating and shot blasting can improve the corrosion resistance of TP304H steel, and combined treatment has the best effect. Combined treatment reduces 50% mass gain, enhances the continuous and compactness of scale and changes the scale phase forms from Fe2O3/Fe1-xS/Ni1-x/S to Cr2O3/FeCr2S4/Ni3-xS2. The synergistic effects of combined treatment on corrosion resistance and the effect of shot blasting on corrosion kinetics are discussed. Shot blasting increases the outward diffusion and surface concentration of Cr, Ce coating promotes the selective oxidation of Cr.

  15. Synergic Effect of Shot Blasting and Deposit RE on Corrosion Behavior of TP304H steel in SO2-O2 at 923K

    Institute of Scientific and Technical Information of China (English)

    LIXin-geng; FUMin; HEJa-wen

    2004-01-01

    The corrosion behavior of TP304H steel with combined treatment of shot blasting and electrophoresis deposited RE coating in 1%SO2+14%O2+85%Ar mixture gaseous has been studied at 923K for 150 hours. The results show that both RE coating and shot blasting can improve the corrosion resistance of TP304H steel, and combined treatment has the best effect. Combined treatment reduces 50% mass gain, enhances the continuous and compactness of scale and changes the scale phase forms from Fe2O3/Fe1-xS/Ni1-x/S to Cr2O3/FeCr2Sn/Ni3-xS2. The synergistic effects of combined treatment on corrosion resistance and the effect of shot blasting on corrosion kinetics are discussed. Shot blasting increases the outward diffusion and surface concentration of Cr, Ce coating promotes the selective oxidation of Cr.

  16. Effect of blasts on subject-specific computational models of skin and bone sections at various locations on the human body

    Directory of Open Access Journals (Sweden)

    Arnab Chanda

    2015-11-01

    Full Text Available Blast injuries are very common among soldiers deployed in politically unstable regions such as Afghanistan and Iraq, and also in a battle field anywhere in the world. Understanding the mechanics of interaction of blasts with the skin and bone at various parts of the human body is the key to designing effective personal protective equipment (PPE's which can mitigate blast impacts. In the current work, subject-specific 3D computational models of the skin (with the three layers namely the epidermis, dermis and the hypodermis (muscles and bone sections from various parts of the human body (such as the elbow, finger, wrist, cheek bone, forehead, shin etc. have been developed to study the effect of blast loading. Non-linear material properties have been adopted for the skin and stress impulses at the different skin layers and bone sections are estimated. To date, such an extensive study on the effect of blast loading on the human skin and bone has not been attempted. The results of this study would be indispensable for medical practitioners to understand the effect of blast trauma and plan effective post-traumatic surgical strategies, and also for developing better PPE designs for the military in the future.

  17. Blast wave parameters at diminished ambient pressure

    Science.gov (United States)

    Silnikov, M. V.; Chernyshov, M. V.; Mikhaylin, A. I.

    2015-04-01

    Relation between blast wave parameters resulted from a condensed high explosive (HE) charge detonation and a surrounding gas (air) pressure has been studied. Blast wave pressure and impulse differences at compression and rarefaction phases, which traditionally determine damage explosive effect, has been analyzed. An initial pressure effect on a post-explosion quasi-static component of the blast load has been investigated. The analysis is based on empirical relations between blast parameters and non-dimensional similarity criteria. The results can be directly applied to flying vehicle (aircraft or spacecraft) blast safety analysis.

  18. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors

    OpenAIRE

    Feddema, Rick Thomas

    2013-01-01

    Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas...

  19. Effect of Na3PO4 on the Hydration Process of Alkali-Activated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Lukáš Kalina

    2016-05-01

    Full Text Available In recent years, the utilization of different non-traditional cements and composites has been increasing. Alkali-activated cementitious materials, especially those based on the alkali activation of blast furnace slag, have considerable potential for utilization in the building industry. However, alkali-slag cements exhibit very rapid setting times, which are too short in some circumstances, and these materials cannot be used for some applications. Therefore, it is necessary to find a suitable retarding admixture. It was shown that the sodium phosphate additive has a strong effect on the heat evolution during alkali activation and effectively retards the hydration reaction of alkali-activated blast furnace slag. The aim of the work is the suggestion of a reaction mechanism of retardation mainly based on Raman and X‑ray photoelectron spectroscopy.

  20. Device for Underwater Laboratory Simulation of Unconfined Blast Waves

    OpenAIRE

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-01-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast press...

  1. Blasting side effects - investigations in an opencast coal mine in India

    International Nuclear Information System (INIS)

    Field investigations were conducted in a potential opencast coal mine in India in order to optimise blast patterns for controlling ground vibration, sound pressure level and fly rock within safe and tolerable limits. Blasting was performed in all operating benches (alluvium, sandstone, shale coal) and blast vibrations were monitored on the alluvial soil present in the vicinity of the mine. It was observed that in all the blasting rounds, low frequency ground vibrations were generated. Further investigations were carried out by recording structural response to ground vibration on single and double storied buildings. It was found that the ground vibrations were amplified by structures themselves, as much as 2.0 to 5.6. times. 2 refs., 4 figs., 5 tabs

  2. INFLUENCE OF SEISMIC BLASTING EFFECT ON NEIGHBOURING STRUCTURES (A COMPARATIVE ANALYSIS)

    OpenAIRE

    Stjepan Strelec; Ivan Baturić; Branko Božić

    1993-01-01

    The article gives a comparative analysis of allowed explosive quantities at blasting in the limestone quarry »Špica« (Ljubeščica, Hrvatsko Zagorje) executed were precise measurings after mass blasting. The measurings were performed at two observation spots, with three-component geophones and a comparative analysis, considering the criteria in the world are described (the paper is published in Croatian).

  3. Adenovirus-mediated human β-nerve growth factor gene transfer has a protective effect on cochlear spiral ganglion after blast exposure

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective: To study whether adenovirus-mediated human β-nerve growth factor (Ad-hNGFβ) gene has any protective effect on blast hearing impairment. Methods:Deafness was induced by blast exposure (172. 0 dB) in 30 healthy guinea pigs. On day 7 of blast exposure, Ad-hNGFβ was infused into the perilymphatic space of 20 animals as the study group (hNGFβ group), and artificial perilymph fluid (APF) was infused into the perilymphatic space of the other 10 animals as the control group. At weeks 1, 4 and 8 after blast exposure, the animals were sacrificed and the cochleae were removed for immunohis-tochemical and HE stainings. Results: Expression of Ad-hNGFβ protein was detected in each turn of the cochlea at the 1st week, with almost equal intensity in all turns. At the 4th week, the reactive intensity of the expression of Ad-hNGFβ protein decreased. At the 8th week, no expression was detectable. The results of HE staining showed that the amount of spiral ganglions in hNGFβ group was significantly greater than that of the control group at week 4 (F<0. 01). Conclusion: Ad-hNGFβ can be expressed at a high level and for a relatively long period in the blast impaired cochlea, suggesting that Ad-hNGFβ has a protective effect on cochlear spiral ganglion cells after blast exposure and the efficient gene transfer into cochlea had been achieved without toxicity.

  4. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

    CERN Document Server

    Courtney, Michael

    2011-01-01

    Instrumentation is needed to produce realistic blast waves in a laboratory setting. This paper describes the development and characterization of oxy-acetylene driven, laboratory scale shock tubes for use in studying blast injury, candidate armor materials, and material properties at blast loading rates. The pressure-time profiles show a true shock front and exponential decay characteristic of blast waves and have relevant durations. The modular design includes shock tube diameters of 27 mm and 41 mm, and a selection of peak pressures from 204 kPa to 920 kPa can be produced by selection of the driver section diameter and placement of the test sample. Characterization studies of several driver/driven section combinations showed consistent results, with peak pressures having 0.8 - 6.9 percent uncertainty in the mean. This shock tube design provides a more realistic blast profile than current air-driven shock tubes. In addition, operation does not require specialized personnel or facilities like most blast-driven...

  5. Effect of blast furnace slag on self-healing of microcracks in cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haoliang, E-mail: haoliang.huang@tudelft.nl [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Ye, Guang [Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology (Netherlands); Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University (Belgium); Damidot, Denis [Université Lille Nord de France (France); EM Douai, LGCgE-MPE-GCE, Douai (France)

    2014-06-01

    The physico-chemical process of self-healing in blast furnace slag cement paste was investigated in this paper. With a high slag content i.e., 66% in cement paste and saturated Ca(OH)₂ solution as activator, it was found that the reaction products formed in cracks are composed of C-S-H, ettringite, hydrogarnet and OH–hydrotalcite. The fraction of C-S-H in the reaction products is much larger than the other minerals. Large amount of ettringite formed in cracks indicates the leaching of SO₄⁻² ions from the bulk paste and consequently the recrystallization. Self-healing proceeds fast within 50 h and then slows down. According to thermodynamic modeling, when the newly formed reaction products are carbonated, the filling fraction of crack increases first and then decreases. Low soluble minerals such as silica gel, gibbsite and calcite are formed. Compared to Portland cement paste, the potential of self-healing in slag cement paste is higher when the percentage of slag is high. Highlights: • Self-healing reaction products in slag cement paste were characterized. • Self-healing reaction products formed in time were quantified with image analysis. • Self-healing in slag cement paste was simulated with a reactive transport model. • Effect of carbonation on self-healing was investigated by thermodynamic modeling. • Effect of slag on self-healing was discussed based on experiments and simulation.

  6. Numerical simulation of the effect of blast and penetration on reinforced concrete structures

    Science.gov (United States)

    Mencarelli, Andrea

    as well as unconfined, confined, hydrostatic, and triaxial compression behavior. LDPM will be calibrated and validated simulating a group of experimental tests both in compression and tension. Regarding compression: uniaxial confined and unconfined, biaxial, triaxial, and hydrostatic tests will be simulated, considering also cases of cyclic loads. Regarding tension: three point bending and splitting tests will be simulated. In every test stress-strain or force-displacement results and failure modes will be compared, with very good agreement, with the experimental results. LDPM will be extended to simulate rate effect, and a group of experimental test simulations will be presented. Uniaxial unconfined compression and Hopkinson Bar in tension will be simulated to calibrate and validate the dynamic parameters. LDPM dynamic implementation will be used to investigate brick fragmentation, projectile impact on reinforced concrete walls, and wall subjected to blast. Finally, conclusions will be discussed: model capabilities will be summarized, and future works will be listed.

  7. The Study of the Grit-blasting Parameters and Their Effects on the Adhesive Strength of the Plasma Sprayed Coatings

    Institute of Scientific and Technical Information of China (English)

    M; Heydarzadeh; Sohi; M; Frooghieh; Sh; Khameneh; Asl

    2002-01-01

    Surface Preparation is very important in adhesive b on ding of spray coatings to the surface of a work piece. The common practice is gr it-blasting of the surface before subjecting it to the spray coating process. In this study, grit-blasting of an AISI 4130 steel (of different heat treatmen ts) with Al 2O 3 particles was studied. Various grit-blasting parameters such as blasting particle size, the distance between blasting nozzle and the work pi ece (25, 30 and 40 cm.), blasting pressure (3,4,5,6 and ...

  8. Assessment of the Effects of Acute and Repeated Exposure to Blast Overpressure in Rodents: Towards a Greater Understanding of Blast and the Potential Ramifications for Injury in Humans Exposed to Blast

    Directory of Open Access Journals (Sweden)

    Stephen Thomas Ahlers

    2012-03-01

    Full Text Available Mild traumatic brain injury (mTBI resulting from exposure to improvised explosive devices (IEDs has fueled a requirement to develop animals models that mirror this condition using exposure to blast overpressure (BOP. En route to developing a model of repeated exposure to BOP we sought to initially characterize the effects of acute BOP exposure in rodents, focusing specifically on the levels of BOP exposure that produced clinical mTBI symptoms. We first measured BOP effects on gross motor function on a balance beam. Separate groups of unanesthetized rats were exposed (in different orientations to 40 kPa, 75 kPa and 120 kPa BOP exposure inside a pneumatically driven shock tube. Results demonstrated that rats exposed to 120 kPa demonstrated transient alterations or loss of consciousness indicated by a transient loss of righting and by increased latencies on the balance beam. The 120 kPa exposure was the threshold for overt pathology for acute BOP exposure with approximately 30% of rats presenting with evidence of subdural hemorrhage and cortical contusions. All animals exposed to 120 kPa BOP manifested evidence of significant pulmonary hemorrhage. Anterograde memory deficits were observed in rats exposed to 75 kPa facing the BOP wave and rats exposed to 120 kPa in the lateral (side orientation. We next assessed repeated exposure to either lateral or frontal 40 kPa BOP in anesthetized rats, once per day for 12 days. Results showed that repeated exposure in the frontal, but not side, orientation to the BOP wave produced a transitory learning deficit on a Morris water maze (MWM task as shown by significantly longer latencies to reach the submerged platform in the second and third blocks of a four block session. Implications of these data are discussed in relation to the manifestation of mTBI in military personnel exposed to IEDs. Finally, we suggest that there are multiple types of brain injury from blast.

  9. Blasting Vibration Generated by Breaking-Blasting Large Barriers with EBBLB

    Directory of Open Access Journals (Sweden)

    Wang Zhen-xiong

    2016-01-01

    Full Text Available Equipment for breaking and blasting large barriers (EBBLB is new break-blast equipment, which inevitably induces ground vibration and may cause substantial damage to rock mass and nearby structures as well as human beings. The ground vibration induced by break-blast is one of the inevitable outcomes. By monitoring vibration at measuring points at different distances from blasting center, time history curve of vibrating velocity can be obtained; it can be drawn that blasting seismic waves are generated mainly from the explosion of the precharge. Furthermore, different approaches have been adopted to fit relationship between particle peak velocity (PPV and distance from blasting center, comparative analysis of which provides the most appropriate relation expression to predict attenuation of PPV of vibration with distance from blasting center. The relation between vibration frequency and distance from blasting center is obtained by Fourier transform. And the research decomposes vibrating signals in vertical direction of different distances from blasting center with Hilbert-Huang Transform (HHT, extracting information of empirical mode components of blasting vibration signals; thus vibrating signals are contracted by spectrum information and energy information, three-dimensional energy, and energy attenuation of vibration with different distances from blasting center. The study can predict ground vibration generated by EBBLB and assess its damaging effects of blasting vibration for security and protection.

  10. Blast Valve Design and Related Studies : A Review

    Directory of Open Access Journals (Sweden)

    P. K. Sharma

    2016-04-01

    Full Text Available The protective structures required for performing critical operations are vulnerable to the blast and shock loads of advanced weapons. A blast valve is an important component of such structures for ventilation during normal conditions and for protection from blast/ shock during explosion. In this paper, various aspects of blast valve design and related studies are briefly reviewed. The concept and effects of blast wave, blast impact, numerical modelling and deformation of circular plate (one of the critical components of blast valve have been discussed. The merits and demerits of sensing mechanisms viz. remote and direct sensing are discussed. The leakage of blast pressure during finite closing period of the valve (one of the critical problems and the shock tube as a major experimental facility for testing of blast valves are briefly discussed.

  11. Effects of internal heat transfer on the structure of self-similar blast waves

    Science.gov (United States)

    Ghoniem, A. F.; Berger, S. A.; Oppenheim, A. K.; Kamel, M. M.

    1982-01-01

    An analysis of the problem of self-similar, nonadiabatic blast waves, where both conduction and radiation are allowed to take place, show the problem to be reducible to the integration of a system of six coupled nonlinear ordinary differential equations. Consideration of these equations shows that although radiation tends to produce uniform fields through temperature gradient attenuation, all the energy carried by radiation is deposited on the front and the bounding shock becomes increasingly overdriven. When conduction is taken into account, the distribution of gasdynamic parameters in blast waves in the case of Rosseland diffusion radiation is more uniform than in the case of the Planck emission radiation.

  12. Effect of shot blasting on processoxidised stainless steel – morphology,chemistry and pickling performance

    OpenAIRE

    Myrsell, Johan

    2014-01-01

    The oxide scale created during manufacturing of stainless steel is often removed by a chemical pickling with mixed acid. Various pre-treatments to pickling are also applied to increase the efficiency of the oxide scale removal. Shot blasting is one such pre-treatment, which operates to remove a certain amount of oxide and also to generate cracks and openings for the subsequent pickling. In this work, three materials, AISI 2205, 430 and 304 have been blasted and later exposed to mixed acid. Th...

  13. CONTROL OF FRAGMENTATION BY BLASTING

    OpenAIRE

    1998-01-01

    The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the q...

  14. Blast Waves

    CERN Document Server

    Needham, Charles E

    2010-01-01

    The primary purpose of this text is to document many of the lessons that have been learned during the author’s more than forty years in the field of blast and shock. The writing therefore takes on an historical perspective, in some sense, because it follows the author’s experience. The book deals with blast waves propagating in fluids or materials that can be treated as fluids. It begins by distinguishing between blast waves and the more general category of shock waves. It then examines several ways of generating blast waves, considering the propagation of blast waves in one, two and three dimensions as well as through the real atmosphere. One section treats the propagation of shocks in layered gases in a more detailed manner. The book also details the interaction of shock waves with structures in particular reflections, progressing from simple to complex geometries, including planar structures, two-dimensional structures such as ramps or wedges, reflections from heights of burst, and three-dimensional st...

  15. Effect of Surface Contaminants Remained on the Blasted Surface on Epoxy Coating Performance and Corrosion Resistance

    International Nuclear Information System (INIS)

    One of the critical issues in the coating specification is the allowable limit of surface contaminant(s) - such as soluble salt(s), grit dust, and rust - after grit blasting. Yet, there is no universally accepted data supporting the relationship between the long-term coating performance and the amount of various surface contaminants allowed after grit blasting. In this study, it was attempted to prepare epoxy coatings applied on grit-blasted steel substrate dosed with controlled amount of surface contaminants - such as soluble salt(s), grit dust, and rust. Then, coating samples were subjected to 4,200 hours of cyclic test(NORSOK M-501), which were then evaluated in terms of resistance to rust creepage, blistering, chalking, rusting, cracking and adhesion strength. Additional investigations on the possible damage at the paint/steel interface were carried out using an Electrochemical Impedance Spectroscopy(EIS) and observations of under-film-corrosion. Test results suggested that the current industrial specifications were well matched with the allowable degree of rust, whereas the allowable amount of soluble salt and grit dust after grit blasting showed a certain deviation from the specifications currently employed for fabrication of marine vessels and offshore facilities

  16. Effect of root and leaf applications of soluble silicon on blast development in rice

    Directory of Open Access Journals (Sweden)

    Isaias Severino Cacique

    2013-01-01

    Full Text Available Blast, caused by Pyricularia oryzae, is the most important fungal disease of rice worldwide. This study aimed to compare root and foliar supply of soluble silicon (Si on rice resistance to blast. The application of soluble Si to the roots increased Si concentration in leaf tissues as compare to plants grown in soil amended with calcium silicate. There was no increase in leaf Si concentration after soluble Si spray, regardless if the leaves were washed or not before analysis. X-ray microanalysis revealed that Si deposition was very similar on the leaf epidermis of plants sprayed with soluble Si, root amended with soluble Si or grown in soil amended with calcium silicate. The lesion size, the number of lesions per cm² of leaf and the area under blast progress curve were reduced for rice plants grown in soil that received the application of soluble Si or was amended with calcium silicate. The results of this study showed that the supply of soluble Si to the roots or its spray onto to the rice leaves can decrease blast symptoms.

  17. Effect of nut coke on the performance of the ironmaking blast furnace

    NARCIS (Netherlands)

    Song, Q.

    2013-01-01

    The blast furnace consumes a large amount of high quality metallurgy coke (size 35-80 mm) in addition to ore in the form of pellets and sinter. This coke is the coarse fraction, derived from the coke plant. The fine fraction (8 -35 mm), arise after sieving, named nut coke, can’t be directly used in

  18. Study of mass attenuation coefficients and effective atomic numbers of bismuth-ground granulated blast furnace slag concretes

    Science.gov (United States)

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    Five samples of Bismuth-Ground granulated blast furnace slag (Bi-GGBFS) concretes were prepared using composition (0.6 cement + x Bi2O3 + (0.4-x) GGBFS, x = 0.05, 0.10, 0.15, 0.20 and 0.25) by keeping constant water (W) cement (C) ratio. Mass attenuation coefficients (μm) of these prepared samples were calculated using a computer program winXCOM at different gamma ray energies, whereas effective atomic numbers (Zeff) is calculated using mathematical formulas. The radiation shielding properties of Bi-GGBFS concrete has been compared with standard radiation shielding concretes.

  19. The Effect of Initial Conditions on the Nonlinear Evolution of Perturbed Interfaces Driven by Strong Blast Waves

    Energy Technology Data Exchange (ETDEWEB)

    Miles, A

    2004-04-27

    In core-collapse supernovae, strong blast waves drive interfaces susceptible to Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH) instabilities. In addition, perturbation growth can result from material expansion in large-scale velocity gradients behind the shock front. Laser-driven experiments are designed to produce a strongly shocked interface whose evolution is a scaled version of the unstable hydrogen-helium interface in core-collapse supernovae such as SN 1987A. The ultimate goal of this research is to develop an understanding of the effect of hydrodynamic instabilities and the resulting transition to turbulence on supernovae observables that remain as yet unexplained. In this dissertation, we present a computational study of unstable systems driven by high Mach number shock and blast waves. Using multi-physics radiation hydrodynamics codes and theoretical models, we consider the late nonlinear instability evolution of single mode, few mode, and multimode interfaces. We rely primarily on 2D calculations but present recent 3D results as well. For planar multimode systems, we show that compressibility effects preclude the emergence of a regime of self-similar instability growth independent of the initial conditions (IC's) by allowing for memory of the initial conditions to be retained in the mix-width at all times. The loss of transverse spectral information is demonstrated, however, along with the existence of a quasi-self-similar regime over short time intervals. Aspects of the IC's are shown to have a strong effect on the time to transition to the quasi-self-similar regime. With higher-dimensional blast waves, divergence restores the properties necessary for establishment of the self-similar state, but achieving it requires very high initial characteristic mode number and high Mach number for the incident blast wave. We point to recent stellar calculations that predict IC's we find incompatible with self-similarity, and

  20. The effect of blast furnace slag on the self-compactability of pumice aggregate lightweight concrete

    Indian Academy of Sciences (India)

    Murat Kurt; Türkay Kotan; Muhammed Said Gül; Rüstem Gül; Abdulkadir Cüneyt Aydin

    2016-02-01

    This paper presents the results of an experimental study of the effects of blast furnace slag, different water/(cement+mineral additive) ratios and pumice aggregates on some physical and mechanical properties of self-compacting lightweight aggregate concrete. In this study, pumice was used as lightweight aggregate. Several properties of self-compacting pumice aggregate lightweight concretes, such as unit weight, flow diameter, T50 time, flow diameter after an hour, V-funnel time, and L-box tests, 7, 28, 90 and 180-day compressive strength, 28-day splitting tensile strength, dry unit weight, water absorption, thermal conductivity and ultrasonic pulse velocity tests, were conducted. For this purpose, 18 series of concrete samples were prepared in two groups. In the first group, pumice aggregate at 100% replacement of natural aggregate was used in the production of self-compacting lightweight aggregate concrete with constant w/(c+m) ratios as 0.35, 0.40, and 0.45 by weight. Furthermore, as a second group, pumice aggregate was used as a replacement of natural aggregate, at the levels of 0, 20, 40, 60, 80, and 100% by volume. Flow diameters, T50 times, paste volumes, 28-day compressive strengths, dry unit weights, thermal conductivities and ultrasonic pulse velocity of self-compacting lightweight aggregate concrete were obtained over the range of 600–770 mm, 3–9 s, 435–540 l/m3, 10.6–65.0 MPa, 845–2278 kg/m3, 0.363–1.694 W/mK and 2617–4770 m/s respectively, which satisfies not only the strength requirement of semistructural lightweight concrete but also the flowing ability requirements and thermal conductivity requirements of self-compacting lightweight aggregate concrete.

  1. Time-dependent and radiation field effects on collisional-radiative simulations of radiative properties of blast waves launched in clusters of xenon

    Science.gov (United States)

    Rodriguez, R.; Espinosa, G.; Gil, J. M.; Rubiano, J. G.; Mendoza, M. A.; Martel, P.; Minguez, E.; Symes, D. R.; Hohenberger, M.; Smith, R. A.

    2015-12-01

    Radiative shock waves are ubiquitous throughout the universe and play a crucial role in the transport of energy into the interstellar medium. This fact has led to many efforts to scale the astrophysical phenomena to accessible conditions. In some laboratory experiments radiative blast waves are launched in clusters of gases by means of the direct deposition of the laser energy. In this work, by using a collisional-radiative model, we perform an analysis of the plasma level populations and radiative properties of a blast wave launched in a xenon cluster. In particular, for both the shocked and unshocked material, we study the influence of different effects such as LTE, steady-state or time-dependent NLTE simulations, plasma self-absorption or external radiation field in the determination of those properties and also in the diagnosis of the electron temperature of the blast wave.

  2. Nonlinear growth of dynamical overstabilities in blast waves. [effects on supernova remnants

    Science.gov (United States)

    Mac Low, Mordecai-Mark; Norman, Michael L.

    1993-01-01

    The numerical gasdynamics code ZEUS-2D is used to directly model the dynamical overstabilities in blast waves. The linear analysis is confirmed by perturbing a blast wave with a low-amplitude eigenfunction of the overstability. The amplitude of the perturbations is increased in order to determine the nonlinear behavior of the overstabilities. The overstability is found to saturate due to weak transverse shocks in the shell. Transverse velocities in the dense shell reach the postshock sound speed, and high-density regions with sizes of the order of the shell thickness form. Transverse oscillations continue even after saturation. This confirms and explains the damping of the overstability experimentally discovered by Grun et al. (1991).

  3. A blast absorber test: measurement and model results

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Berg, F. van den; Hof, J. van 't; Arkel, E. van

    2006-01-01

    A blast absorber test was conducted at the Aberdeen Test Centre from 13 to 17 June 2005. The test was set up to determine the absorbing and shielding effect of a gravel pile, of 1.5 meters high and 15 by 15 meters wide, on blasts from large weapons: e.g. armor, artillery or demolition. The blast was

  4. Analysis and Numerical Simulation on the Reduction Effect of Stress Waves Caused by Water Jet Slotting Near Blasting Source

    Directory of Open Access Journals (Sweden)

    Dengfeng Su

    2016-01-01

    Full Text Available As one of the most serious “side effects” of blast excavation, blast-induced vibration must be controlled for existing buildings and human beings. This paper proposes a method for blast-induced vibration reduction with water jet assistance according to the cutting characters of low-noised, environment-friendly water jet. The mechanism of vibration-isolation with water jet assistance was analyzed, and the stress wave energy attenuation models were established based on blasting theory and stress wave theory. Influence law on shock wave attenuation by vibration-isolation slot was studied by numerical simulation. Simulation results agree with the theoretical analysis roughly. The results of this study put forward a method for blast-induced vibration near blasting source and provide a certain theoretical basis.

  5. Simulation of blast-induced, early-time intracranial wave physics leading to traumatic brain injury.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul Allen; Ford, Corey C. (University of New Mexico, Albuquerque, NM)

    2008-04-01

    U.S. soldiers are surviving blast and impacts due to effective body armor, trauma evacuation and care. Blast injuries are the leading cause of traumatic brain injury (TBI) in military personnel returning from combat. Understanding of Primary Blast Injury may be needed to develop better means of blast mitigation strategies. The objective of this paper is to investigate the effects of blast direction and strength on the resulting mechanical stress and wave energy distributions generated in the brain.

  6. Comparative study on effects of burn-blast combined injury and burn-firearm combined injury complicated with seawater immersion on vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; LAI Xi-nan; GE Heng-jiang

    2005-01-01

    Objective: To comparatively study the effects and mechanisms of burn-blast combined injury and burn-firearm combined injury complicated with seawater immersion on vascular endothelial cells. Methods: A total of 40 healthy adult hybrid dogs of both sexes, weighing 12-15 kg, were used in this study. Randomly-selected 20 dogs were established as models of burn-blast combined injury (the burn-blast injury group) and the other 20 dogs as models of burn-firearm combined injury (the burn-firearm injury group). Then the wounds of all the dogs were immediately immersed in seawater for 4 hours, and then they were taken out from the seawater. Blood samples were withdrawn from the central vein of the dogs before injury, and at 4, 7, 10, 20, and 28 hours after injury to measure the circulating endothelial cells and the von Willebrand factor. Results: Circulating endothelial cells increased significantly at 4 hours after injury in all the dogs. But they reached peak at 7 hours after injury in the burn-blast injury group and at 28 hours after injury in the burn-firearm injury group. The changes of circulating endothelial cells in the burn-blast injury group were significantly different from those in the burn-firearm injury group at 4, 7, 20, and 28 hours after injury (P<0.01). The von Willebrand factor reached peak at 4 hours after injury in the burn-blast injury group and at 28 hours in the burn-firearm injury group. The changes of von Willebrand factor in the burn-blast injury group were significantly different from those in the burn-firearm injury group at 4, 20, and 28 hours after injury (P<0.01).Conclusions: In burn-blast injury combined with seawater immersion, the vascular endothelial cells changed most significantly at 4 hours or 7 hours after injury, while burn-firearm injury combined with seawater immersion have the same at 20 hours or 28 hours after injury.

  7. STUDY ON BLASTING DESCALING IN THE SOOT-DELIVERY PIPE

    Institute of Scientific and Technical Information of China (English)

    杨仁树; 田运生; 商厚胜; 杨永琦; 齐郁周

    1997-01-01

    An experiment model, scaled 1:1, designed for studying a blasting method to clear away soot in a soot-delivery pipe in coal-burning power plant is described. By mixing RDX and Nitramon on a particular scale and sticking the explosive cartridge on the outwall surface of the pipe, the experimental result makes clear that the controlled blasting method can get rid of the soot effectively. Under the action of the blasting compression wave and reflectance tension wave, the soot is destroyed effectively in the region of-60°~60° around the blasting site, that creates a condition for the second blasting in the surplus soot.

  8. Effects of 5-azacytidine on natural killer cell activating receptor expression in patients with refractory anemia with excess of blasts

    Directory of Open Access Journals (Sweden)

    Régis T. Costello

    2015-01-01

    Full Text Available Epigenetic drugs modify DNA methylation and are used in refractory anemia with excess of blasts (RAEB. These drugs may reactivate anti-oncogene expression and restore a normal phenotype instead of inducing antitumor toxicity, although they also have immunosuppressive effects on T-lymphocytes [1] In RAEB and acute myeloid leukemia, a defect in natural killer (NK cell cytotoxicity has been shown, which relies on abnormal expression of activating receptors. Previous study has shown that 5-azacytidine impaired mRNA synthesis and induced apoptosis in NK cells [2]. In this study we investigated the effect of the demethylating drug 5-azacytidine (Vidaza® on NK receptors with the hypothesis that demethylation of the promoters of activating NK receptor genes induces gene reactivation and thus may increase their expression.

  9. Effects of 5-azacytidine on natural killer cell activating receptor expression in patients with refractory anemia with excess of blasts

    Science.gov (United States)

    Costello, Régis T.; Leclercq, Amélie; Treut, Thérèse Le; Sanchez, Carole; Mercier, Delphine; Sébahoun, Gérard

    2015-01-01

    Epigenetic drugs modify DNA methylation and are used in refractory anemia with excess of blasts (RAEB). These drugs may reactivate anti-oncogene expression and restore a normal phenotype instead of inducing antitumor toxicity, although they also have immunosuppressive effects on T-lymphocytes [1] In RAEB and acute myeloid leukemia, a defect in natural killer (NK) cell cytotoxicity has been shown, which relies on abnormal expression of activating receptors. Previous study has shown that 5-azacytidine impaired mRNA synthesis and induced apoptosis in NK cells [2]. In this study we investigated the effect of the demethylating drug 5-azacytidine (Vidaza®) on NK receptors with the hypothesis that demethylation of the promoters of activating NK receptor genes induces gene reactivation and thus may increase their expression. PMID:25709892

  10. Effects of 5-azacytidine on natural killer cell activating receptor expression in patients with refractory anemia with excess of blasts.

    Science.gov (United States)

    Costello, Régis T; Leclercq, Amélie; Treut, Thérèse Le; Sanchez, Carole; Mercier, Delphine; Sébahoun, Gérard

    2015-01-01

    Epigenetic drugs modify DNA methylation and are used in refractory anemia with excess of blasts (RAEB). These drugs may reactivate anti-oncogene expression and restore a normal phenotype instead of inducing antitumor toxicity, although they also have immunosuppressive effects on T-lymphocytes [1] In RAEB and acute myeloid leukemia, a defect in natural killer (NK) cell cytotoxicity has been shown, which relies on abnormal expression of activating receptors. Previous study has shown that 5-azacytidine impaired mRNA synthesis and induced apoptosis in NK cells [2]. In this study we investigated the effect of the demethylating drug 5-azacytidine (Vidaza(®)) on NK receptors with the hypothesis that demethylation of the promoters of activating NK receptor genes induces gene reactivation and thus may increase their expression. PMID:25709892

  11. Effect of sand blasting on structural, thermal, and mechanical properties of Zr{sub 58.3}Cu{sub 18.8}Al{sub 14.6}Ni{sub 8.3} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Tariq, Naeem ul Haq; Awais, Hasan Bin; Naeem, Muhammad; Shahid, Rub Nawaz [Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan). Dept. of Metallurgy and Materials Engineering; Akhter, Javaid Iqbal [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Physics Div.

    2012-07-15

    In the present work sand-blasting-induced structural, thermal, and mechanical effects were studied in Zr{sub 58.3}Cu{sub 18.8}Al{sub 14.6}Ni{sub 8.3} bulk metallic glass. It was observed that sand blasting favors disordering of the atomic configuration, formation of free volume and evolution of multiple intersecting shear bands. As a result, considerable compressive plasticity was achieved in sand-blasted samples. It was also observed that in order to superimpose the effect of prestraining and extra free volume for improving compressive plasticity, there exists a limit to both parameters. (orig.)

  12. Effect of grit blasting on the thermal cycling behavior of diffusion aluminide/YSZ TBCs

    International Nuclear Information System (INIS)

    Highlights: • TBCs including of CVD NiAl bond coat and EB-PVD YSZ ceramic coating with and without grit blasting process. • Grain boundary ridges are the sites for spallation damage initiation in aluminide/YSZ TBCs. • Ridges are removed, and no cavity formation and this damage initiation mode are suppressed. • Damage initiation and progression occurs at the bond coat to TGO interface leading to a buckling failure behavior. -- Abstract: Thermal barrier coating system (TBCs) including of chemical vapor deposited NiAl bond coat and electron beam physical vapor deposited Y2O3–stabilized-ZrO2 (YSZ) ceramic coating with and without grit blasting process were investigated. The phase structures, surface and cross-sectional morphologies, cyclic oxidation behaviors of these coatings were studied in detail. Grain boundary ridges form on the surface of aluminide bond coat prior to the deposition of the ceramic coating by EB-PVD, which are shown to be the sites for spallation damage initiation in aluminide/YSZ TBCs. When these ridges are removed, there is no cavity formation and this damage initiation mode is suppressed. Damage initiation and progression occurs at the bond coat to TGO interface leading to a buckling failure behavior. A buckle failure once started may be arrested when it runs into a region of high bond coat to TGO interface toughness. Thus, complete failure requires further loss in toughness of the bond coat to TGO interface with additional cycling. From the result of thermal cycling, an averaged four folds lifetime improvement can be achieved with samples after grit blasting of bond coat surface as compared with those samples existence in ridges on the bond coats’ surface

  13. The Effect of Blasting in Layered Soils, Example from Finneidfjord, Norway

    OpenAIRE

    Woldeselassie, Bruck Haile

    2012-01-01

    A case study on the role of blast vibration on the 1996 Finneidfjord landslide was carried out. This catastrophic landslide which claimed four lives has been under investigation during the past decade. The study area has been developed as natural laboratory and different field and lab investigation have been carried out in the process of understanding the event bed. The mechanically weak layer that the landslide used as a slip surface is found 2.8-3.1m below the sea bed and is composed of loo...

  14. Simulating geometrically complex blast scenarios

    Directory of Open Access Journals (Sweden)

    Ian G. Cullis

    2016-04-01

    Full Text Available The effects of blast waves generated by energetic and non-energetic sources are of continuing interest to the ballistics research community. Modern conflicts are increasingly characterised by asymmetric urban warfare, with improvised explosive devices (IEDs often playing a dominant role on the one hand and an armed forces requirement for minimal collateral effects from their weapons on the other. These problems are characterised by disparate length- and time-scales and may also be governed by complex physics. There is thus an increasing need to be able to rapidly assess and accurately predict the effects of energetic blast in topologically complex scenarios. To this end, this paper presents a new QinetiQ-developed advanced computational package called EAGLE-Blast, which is capable of accurately resolving the generation, propagation and interaction of blast waves around geometrically complex shapes such as vehicles and buildings. After a brief description of the numerical methodology, various blast scenario simulations are described and the results compared with experimental data to demonstrate the validation of the scheme and its ability to describe these complex scenarios accurately and efficiently. The paper concludes with a brief discussion on the use of the code in supporting the development of algorithms for fast running engineering models.

  15. Simulating geometrically complex blast scenarios

    Institute of Scientific and Technical Information of China (English)

    Ian G. CULLIS; Nikos NIKIFORAKIS; Peter FRANKL; Philip BLAKELY; Paul BENNETT; Paul GREENWOOD

    2016-01-01

    The effects of blast waves generated by energetic and non-energetic sources are of continuing interest to the ballistics research community. Modern conflicts are increasingly characterised by asymmetric urban warfare, with improvised explosive devices (IEDs) often playing a dominant role on the one hand and an armed forces requirement for minimal collateral effects from their weapons on the other. These problems are characterised by disparate length-and time-scales and may also be governed by complex physics. There is thus an increasing need to be able to rapidly assess and accurately predict the effects of energetic blast in topologically complex scenarios. To this end, this paper presents a new QinetiQ-developed advanced computational package called EAGLE-Blast, which is capable of accurately resolving the generation, propagation and interaction of blast waves around geometrically complex shapes such as vehicles and buildings. After a brief description of the numerical methodology, various blast scenario simulations are described and the results compared with experimental data to demonstrate the validation of the scheme and its ability to describe these complex scenarios accurately and efficiently. The paper concludes with a brief discussion on the use of the code in supporting the development of algorithms for fast running engineering models.

  16. Effect of recycling blast furnace flue dust as pellets on the sintering performance

    Directory of Open Access Journals (Sweden)

    El-Hussiny N.A.

    2010-01-01

    Full Text Available The Egyptian Iron and Steel Company generates a great amount of blast furnace flue dust. The recovery of metals and carbon from this flue dust becomes a very important demand due to the increase of the price of coke breeze and the decrease of the primary source of metals. At the same time, it make the environment more safe by decreasing pollution. Introducing these dust fines in the sintering process proves to be very harmful for different operating parameters. Thus, this study aims at investigating the production of pellets resulting from these fines, using molasses as organic binder and its application in sintering of iron ore. The sintering experiments were performed using flue dust as pellets as a substitute of coke breeze. The results revealed that, sintering properties such as inter strength increases with using the flue dust pellets, while productivity of both the sinter machine and sinter machine at blast furnace yard decreases. Also the vertical velocity of the sinter machine and the weight loss during the reduction of produced the sinter by hydrogen decrease.

  17. Vibration velocity and frequency of underwater short-hole blasting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the measuring data of underwater blasting vibrationand the regression analysis results of these data, two formulae usually used of blasting vibration velocity were compared. Factors that canaffect blasting vibration and frequency were summarized and analyzed.It is thought that the effect of the number of freedom face and burden direction on blasting vibration should be considered during blastingdesign. Based on the relevant research results and the regression results of these data, a formula to calculate under water blasting frequency was put forward.

  18. Effects of mechanical cleaning by manual brushing and abrasive blasting on lime render coatings on Architectural Heritage

    Directory of Open Access Journals (Sweden)

    Iglesias-Campos, M. A.

    2014-12-01

    Full Text Available This research studies the effects of mechanical cleaning by brushing and by abrasive blasting on the lime render coating of a façade. After analysing the properties of the material, the deposits to be removed and their possible influence on the treatment, different cleaning tests were made by manual brushing and by blasting with three varieties of abrasives at 45° and 75° angles, keeping the other parameters constant. Taking the restorer’s perspective as a starting point, and in order to fulfil the practical requirements of an intervention, tests were evaluated with macro-photography, USB digital microscope and stereomicroscope with 3D visualization and measurement. From the results can be concluded that abrasives with low friability and greater grain size than the space between mortar aggregates blasted at a 75° angle reduce the differential erosion compared to other abrasives; although manual brushing has less impact on the surface.En este trabajo se estudian los efectos de las limpiezas mecánicas con cepillado y con proyección de abrasivos sobre un revestimiento exterior de cal. Tras documentar las propiedades del material, de los depósitos superficiales y de su posible influencia en el tratamiento, se realizaron diferentes catas de limpieza con cepillado manual y con proyección de tres abrasivos con ángulos de 45° y 75° manteniendo constantes el resto de parámetros. Partiendo de la visión del conservador-restaurador y de un carácter práctico según las necesidades reales de intervención, los ensayos se evaluaron con macrofotografía, microscopio digital USB y microscopio estereoscópico con visualización y medición en 3D. De los resultados se determina que los abrasivos de baja friabilidad y granulometría mayor que el espacio entre los áridos del mortero proyectados con un ángulo de 75° reducen la erosión diferencial en comparación a otros abrasivos, aunque el cepillado manual altera menos la superficie.

  19. Modeling coupled blast/structure interaction with Zapotec, benchmark calculations for the Conventional Weapon Effects Backfill (CONWEB) tests.

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Gregory Carl

    2004-09-01

    Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a

  20. Assessing the Vulnerability of Large Critical Infrastructure Using Fully-Coupled Blast Effects Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McMichael, L D; Noble, C R; Margraf, J D; Glascoe, L G

    2009-03-26

    Structural failures, such as the MacArthur Maze I-880 overpass in Oakland, California and the I-35 bridge in Minneapolis, Minnesota, are recent examples of our national infrastructure's fragility and serve as an important reminder of such infrastructure in our everyday lives. These two failures, as well as the World Trade Center's collapse and the levee failures in New Orleans, highlight the national importance of protecting our infrastructure as much as possible against acts of terrorism and natural hazards. This paper describes a process for evaluating the vulnerability of critical infrastructure to large blast loads using a fully-coupled finite element approach. A description of the finite element software and modeling technique is discussed along with the experimental validation of the numerical tools. We discuss how such an approach can be used for specific problems such as modeling the progressive collapse of a building.

  1. Calculation of driling and blasting parameters in blasting performance

    OpenAIRE

    Dambov, Risto; Karanakova Stefanovska, Radmila; Dambov, Ilija

    2015-01-01

    In all mining technology drilling and blasting parameters and works are one of the main production processes at each mine. The parameters of drilling and blasting and explosives consumption per ton of blasting mass are define economic indicators of any blasting no matter for what purpose and where mining is performed. The calculation of rock blasting should always have in mind that the methodology of calculation of all drilling and blasting parameters in blasting performance are performed for...

  2. Modelling of blast loading on aboveground structures - II. Internal blast and ground shock

    Science.gov (United States)

    Beshara, F. B. A.

    1994-06-01

    Recent studies of the nature and structural effects of confined explosions, contact blast and explosion-induced ground shock are presented. High explosive blast is distinguished from that due to a gaseous deflagration. The effects of confinement and venting are considered in the evaluation of dynamic loads. Maxima for the initial internal blast pressure can be estimated from the scaled blast data or theoretical analyses of normal blast wave reflection from a rigid wall. Semi-empirical relations and prediction methods for gas pressures for many types of internal explosions including high explosives, gas mixtures and dust suspensions are given on the basis of pseudo-static character. The loading of a contact explosion and the associated effects on a concrete target are determined as functions of charge weight, concrete strength and member thickness. In the final part, the evaluation of both airblast-induced ground shock and directly transmitted motion are included in simple form without considering the soil-structure interaction.

  3. Features of energy distribution for blast vibration signals based on wavelet packet decomposition

    Institute of Scientific and Technical Information of China (English)

    LING Tong-hua; LI Xi-bing; DAI Ta-gen; PENG Zhen-bin

    2005-01-01

    Blast vibration analysis constitutes the foundation for studying the control of blasting vibration damage and provides the precondition of controlling blasting vibration. Based on the characteristics of short-time nonstationary random signal, the laws of energy distribution are investigated for blasting vibration signals in different blasting conditions by means of the wavelet packet analysis technique. The characteristics of wavelet transform and wavelet packet analysis are introduced. Then, blasting vibration signals of different blasting conditions are analysed by the wavelet packet analysis technique using MATLAB; energy distribution for different frequency bands is obtained. It is concluded that the energy distribution of blasting vibration signals varies with maximum decking charge,millisecond delay time and distances between explosion and the measuring point. The results show that the wavelet packet analysis method is an effective means for studying blasting seismic effect in its entirety, especially for constituting velocity-frequency criteria.

  4. 高瓦斯低透气煤层松动爆破有效影响范围确定%Determination on Standing Blasting Effective Scope of High Gassy and Low Permeability Seam

    Institute of Scientific and Technical Information of China (English)

    徐伟

    2011-01-01

    利用ANSYS/LS-DYNA软件对松动爆破有效影响范围进行了计算机数值模拟,分别建立了爆破孔间距为5、6、7 m的爆破数值计算模型。通过对模拟结果分析得出:爆破应力波以爆源为中心向四周传播;应力波强度会随着传播距离的增加而不断衰减;在应力波传播的过程中,会发生应力叠加现象;爆破孔间距越大,叠加后应力强度在传播过程的衰减幅度就越小;通过数值模拟和现场检验,最终得出爆破孔间距为6 m时爆破效果最佳。%The ANSYS/LS-DYNA software was applied to the computer numerical simulation on the standing blasting effective scope.The blasting numerical calculation models with the blasting borehole spacing of 5,6 and 7 m were individually established.The analysis on the simulation results showed that the blasting stress wave would be spread to all around based on the blasting source as the center.The stress wave strength would be steadily reduced with the spreading distance increased.During the stress wave spreading process,the stress superposition phenomenon would be occurred.The longer of the blasting borehole spacing,the lower of the attenuation range would be stress strength after the superposition during the spreading process.With the numerical simulation and the site inspection,when the blasting borehole spacing was 6 m,the blasting effect would be best.

  5. Effect of grit blasting surface plastic deformation on structure and hardness of near surface layers of VT3-1 and VT-22 alloys

    International Nuclear Information System (INIS)

    The effect of different grit blasting surface plastic deformation (SPD) conditions on structure and hardness of the VT3-1 and VT-22 titanium alloys are studied by means of metallographic, X-ray diffraction, electron-microscopy, and durometric methods. The alloy cold working layer depth is shown to increase both with the growth of a diameter of balls used during the SPD and pressure on the grit blasting unit nozzle. A correlation between a microhardness change and X-ray diffraction line width as a function of ball diameter is established. It is shown that the highest alloy surface hardening takes place after a grit balsting cold working with balls 0.4x10-3 m in diameter at a pressure of 3x105 Pa

  6. Effect of γ-irradiation on the electrical conductivity of some soda lime silicate glass containing blast furnace slag

    International Nuclear Information System (INIS)

    The effect of electric field strength on conduction in soda lime silicate glass doped with blast furnace slag with different concentration was studied and the value of jump distance was calculated. The structure and the mixed anion effect in the conductivity have been examined by measuring the electrical conductivity of glass samples at temperature ranging between 20 and 250 deg. C. The results showed that the electrical conductivity of the examined glasses are divided into three ranges depending on the temperature range. The first is from room temperature to about 49.5 deg. C, the second is at a temperature range of 60.3-104 deg. C where the glass shows a decrease in its conductivity with the increase in temperature. This was followed by another increase in the electrical conductivity with the increase in temperature. The results also showed that the glass becomes more insulating as the slag content increased. The effect of irradiation was also studied by exposing glass samples to two different irradiation doses. It can be noticed that irradiation causes an increase in the electrical conductivity, especially at high temperature. The results were discussed and correlated according to the molecular structure of the prepared glass

  7. Experimental study of blast mitigating devices based on combined construction

    Science.gov (United States)

    Takayama, K.; Silnikov, M. V.; Chernyshov, M. V.

    2016-09-01

    A robust blast inhibiting bin is the most often used device for damage blast effects suppression. In particular, a top open cylindrical bin significantly reduces a fragmentation effect resulted from a detonation of an explosive device placed inside the bin. However, reduction of blast wave overpressure and impulse by such cylindrical bins is not sufficient [1]. A reasonable alternative to endless increase of height and thickness of robust blast inhibiting bins is a development of destructible inhibitors having no solid elements in their structure and, therefore, excluding secondary fragmentation. So, the family of "Fountain" inhibitors [2,3] localizes and suppresses damaging blast effects due to multiphase working system. The present study is analyzing data obtained in testing of prototypes of new combined inhibitors. Their structure combines robust elements (bottoms, side surfaces) with elements responsible for blast loads reduction due to multi-phase working system (top and low transverse embeddings) and fairings impeding wave propagation in undesirable directions.

  8. Blast Overpressure Waves Induce Transient Anxiety and Regional Changes in Cerebral Glucose Metabolism and Delayed Hyperarousal in Rats

    OpenAIRE

    Awwad, Hibah O.; Gonzalez, Larry P.; Tompkins, Paul; Lerner, Megan; Brackett, Daniel J.; Awasthi, Vibhudutta; Standifer, Kelly M.

    2015-01-01

    Physiological alterations, anxiety, and cognitive disorders are strongly associated with blast-induced traumatic brain injury (blast TBI), and are common symptoms in service personnel exposed to blasts. Since 2006, 25,000–30,000 new TBI cases are diagnosed annually in U.S. Service members; increasing evidence confirms that primary blast exposure causes diffuse axonal injury and is often accompanied by altered behavioral outcomes. Behavioral and acute metabolic effects resulting from blast to ...

  9. Blast overpressure waves induce transient anxiety and regional changes in cerebral glucose metabolism and delayed hyperarousal in rats

    Directory of Open Access Journals (Sweden)

    Hibah Omar Awwad

    2015-06-01

    Full Text Available Physiological alterations, anxiety and cognitive disorders are strongly associated with blast-induced traumatic brain injury (blast TBI and are common symptoms in service personnel exposed to blasts. Since 2006, 25-30,000 new TBI cases are diagnosed annually in U.S. Service members; increasing evidence confirms that primary blast exposure causes diffuse axonal injury and is often accompanied by altered behavioral outcomes. Behavioral and acute metabolic effects resulting from blast to the head in the absence of thoracic contributions from the periphery were examined following a single blast wave directed to the head of male Sprague-Dawley rats protected by a lead shield over the torso. An 80 psi head blast produced cognitive deficits that were detected in working memory. Blast TBI rats displayed increased anxiety as determined by elevated plus maze at day 9 post-blast compared to sham rats; blast TBI rats spent significantly more time than the sham controls in the closed arms (p<0.05; n=8-11. Interestingly, anxiety symptoms were absent at days 22 and 48 post-blast. Instead, blast TBI rats displayed hyperactivity and increased rearing behavior at day 48 post-blast compared to sham rats. Blast TBI rats also exhibited suppressed acoustic startle responses, but similar pre-pulse inhibition at day 15 post-blast compared to sham rats. Acute physiological alterations in cerebral glucose metabolism were determined by positron emission tomography 1 and 9 days post-blast using F-18-fluorodeoxyglucose. Global glucose uptake in blast TBI rat brains increased at day 1 post-blast (p<0.05; n=4-6 and returned to sham levels by day 9. Our results indicate a transient increase in cerebral metabolism following a blast injury. Markers for reactive astrogliosis and neuronal damage were noted by immunoblotting motor cortex tissue from day 10 post-blast in blast TBI rats compared to sham controls (p<0.05; n=5-6.

  10. Blast Overpressure Waves Induce Transient Anxiety and Regional Changes in Cerebral Glucose Metabolism and Delayed Hyperarousal in Rats.

    Science.gov (United States)

    Awwad, Hibah O; Gonzalez, Larry P; Tompkins, Paul; Lerner, Megan; Brackett, Daniel J; Awasthi, Vibhudutta; Standifer, Kelly M

    2015-01-01

    Physiological alterations, anxiety, and cognitive disorders are strongly associated with blast-induced traumatic brain injury (blast TBI), and are common symptoms in service personnel exposed to blasts. Since 2006, 25,000-30,000 new TBI cases are diagnosed annually in U.S. Service members; increasing evidence confirms that primary blast exposure causes diffuse axonal injury and is often accompanied by altered behavioral outcomes. Behavioral and acute metabolic effects resulting from blast to the head in the absence of thoracic contributions from the periphery were examined, following a single blast wave directed to the head of male Sprague-Dawley rats protected by a lead shield over the torso. An 80 psi head blast produced cognitive deficits that were detected in working memory. Blast TBI rats displayed increased anxiety as determined by elevated plus maze at day 9 post-blast compared to sham rats; blast TBI rats spent significantly more time than the sham controls in the closed arms (p blast. Instead, blast TBI rats displayed increased rearing behavior at day 48 post-blast compared to sham rats. Blast TBI rats also exhibited suppressed acoustic startle responses, but similar pre-pulse inhibition at day 15 post-blast compared to sham rats. Acute physiological alterations in cerebral glucose metabolism were determined by positron emission tomography 1 and 9 days post-blast using (18)F-fluorodeoxyglucose ((18)F-FDG). Global glucose uptake in blast TBI rat brains increased at day 1 post-blast (p blast injury. Markers for reactive astrogliosis and neuronal damage were noted by immunoblotting motor cortex tissue from day 10 post-blast in blast TBI rats compared to sham controls (p < 0.05; n = 5-6). PMID:26136722

  11. Material Systems for Blast-Energy Dissipation

    Energy Technology Data Exchange (ETDEWEB)

    James Schondel; Henry S. Chu

    2010-10-01

    Lightweight panels have been designed to protect buildings and vehicles from blast pressures by activating energy dissipation mechanisms under the influence of blast loading. Panels were fabricated which featured a variety of granular materials and hydraulic dissipative deformation mechanisms and the test articles were subjected to full-scale blast loading. The force time-histories transmitted by each technology were measured by a novel method that utilized inexpensive custom-designed force sensors. The array of tests revealed that granular materials can effectively dissipate blast energy if they are employed in a way that they easily crush and rearrange. Similarly, hydraulic dissipation can effectively dissipate energy if the panel features a high fraction of porosity and the panel encasement features low compressive stiffness.

  12. Mechanical and Histological Effects of Resorbable Blasting Media Surface Treatment on the Initial Stability of Orthodontic Mini-Implants.

    Science.gov (United States)

    Gansukh, Odontuya; Jeong, Jong-Wha; Kim, Jong-Wan; Lee, Jong-Ho; Kim, Tae-Woo

    2016-01-01

    Introduction. This study aimed to evaluate the effects of resorbable blasting media (RBM) treatment on early stability of orthodontic mini-implants by mechanical, histomorphometric, and histological analyses. Methods. Ninety-six (64 for mechanical study and 32 for histological study and histomorphometric analysis) titanium orthodontic mini-implants (OMIs) with machined (machined group) or RBM-treated (CaP) surface (RBM group) were implanted in the tibiae of 24 rabbits. Maximum initial torque (MIT) was measured during insertion, and maximum removal torque (MRT) and removal angular momentum (RAM) were measured at 2 and 4 weeks after implantation. Bone-to-implant contact (BIC) and bone area (BA) were analyzed at 4 weeks after implantation. Results. RBM group exhibited significantly lower MIT and significantly higher MRT and RAM at 2 weeks than machined group. No significant difference in MRT, RAM, and BIC between the two groups was noted at 4 weeks, although BA was significantly higher in RBM group than in machined group. RBM group showed little bone resorption, whereas machined group showed new bone formation after bone resorption. Conclusions. RBM surface treatment can provide early stability of OMIs around 2 weeks after insertion, whereas stability of machined surface OMIs may decrease in early stages because of bone resorption, although it can subsequently recover by new bone apposition. PMID:26942200

  13. EXPERIMENTAL STUDIES OF MITIGATION MATERIALS FOR BLAST INDUCED TBI

    OpenAIRE

    Young, Laurence Retman; Goel, Rahul; Christou, George Alexander; Son, S. F.; Alley, M. D.

    2009-01-01

    The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the given material to reduce the damage caused by the blast. Several methods of energy transfer in blast wave flows are known or expected including: material interfaces with impedance mismatches, density changes in a given material, internal shearing, and particle fracture. The theory applied to this research is that the greatest energy transfer withi...

  14. 基于 AG-AHP和云物元模型的台阶爆破效果评估研究%Evaluation of bench blasting effect based on GA-AHP and cloud matter element model

    Institute of Scientific and Technical Information of China (English)

    王训洪; 郑明贵

    2015-01-01

    In order to evaluate the bench blasting effect, considering the blasting safety, quality, technology and economy, this study chooses 12 factors to act as the evaluation indexes, such as the blasting flying rocks, boulder yield, blasting efficiency, etc. The weights of evaluation index are determined by applying GA-AHP and an evaluation model of the bench blasting effect which is based on the GA-AHP and matter element model is built. Then the established model is applied to the blasting assessment of four stopes in an open pit mine. Besides, the correlation and overall connection degree of blasting effect are calculated by using Matlab software programming. The result shows that the evaluation results are comparatively consistent with the practice.%为了对台阶爆破效果进行评估,从爆破安全、爆破质量和爆破技术经济三个方面出发,选取了爆破飞石、大块率和爆破效率等12 个影响因素作为评估指标,并利用遗传层次分析法确定了评估指标的权重, 建立了基于AG-AHP和云物元模型的台阶爆破效果评估模型. 将所建立的模型应用于某露天铁矿4个采场爆破评估中,采用Matlab软件编程计算了爆破效果的关联度和综合关联度,研究结果表明:评估效果与实际相吻合.

  15. Localized coating removal using plastic media blasting

    Science.gov (United States)

    Novak, Howard L.; Wyckoff, Michael G.; Zook, Lee M.

    1988-01-01

    Steps taken to qualify the use of plastic media blasting for safely and effectively removing paint and other coatings from solid rocket booster aluminum structures are described. As a result of the effort, an improvement was made in the design of surface finishing equipment for processing flight hardware, in addition to a potentially patentable idea on improved plastic media composition. The general arrangement of the blast equipment and the nozzle configuration are presented.

  16. Analysis on rebound effect of blast door under negative phase pressures%冲击波负压对防护门反弹效应的影响分析

    Institute of Scientific and Technical Information of China (English)

    郭东; 刘晶波; 闫秋实

    2011-01-01

    The rebound effect of blast door was studied under the negative phase of blast loading. The reasonably approximated blast pulse shape was adopted to obtain the exact analytical formulas for rebound force of blast door, taking into account the negative phase effect. The negative phase effect of blast waves on blast door was assessed. It is demonstorated that with the increase of scaled distance, the peak value of negative pressure, relatively to the peak value of positive pressure, increases gradually and in the meantime, negative pressure shows the increasing effects on the rebound of blast door. But the response of this type may emerge only under small overpressure. Due to the small peak values of both positive and negative pressures, the blast door seems to be relatively stiff enough and the blast door would not be damaged by the increased rebound effect. So, the effect of negative pressure might be ignored in the design of protective structures.%对冲击波负压作用下防护门的反弹效应进行了研究,采用合理的荷载假定形式,推导了考虑负压影响的防护门反弹力的精确解析公式,评价了负压对防护门反弹效应的影响规律:即随着比例爆距的增大,负压峰值相对于正压峰值逐渐增大,反弹增大效应也较明显,但这样一个响应可能仅对比较小的超压值才出现,由于正压、负压峰值都较小,防护门刚度较大,故增大的反弹力不足以对防护门造成破坏,设计中可以不考虑负压的影响.

  17. Note: Device for underwater laboratory simulation of unconfined blast waves.

    Science.gov (United States)

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-06-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast pressures of about 1860 kPa. Shot-to-shot consistency was fair, with an average standard deviation near 150 kPa. Results suggest that peak blast pressures from 460 kPa to 1860 kPa are available by adjusting the distance from the source. PMID:26133878

  18. Note: Device for underwater laboratory simulation of unconfined blast waves

    Science.gov (United States)

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-06-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast pressures of about 1860 kPa. Shot-to-shot consistency was fair, with an average standard deviation near 150 kPa. Results suggest that peak blast pressures from 460 kPa to 1860 kPa are available by adjusting the distance from the source.

  19. Device for Underwater Laboratory Simulation of Unconfined Blast Waves

    CERN Document Server

    Courtney, Elijah; Courtney, Michael

    2015-01-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast pressures of about 1860 kPa. Shot-to-shot consistency was fair, with an average standard deviation near 150 kPa. Results suggest peak blast pressures from 460 kPa to 1860 kPa are available by adjusting the distance from the source.

  20. Comparative observation of protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure

    Institute of Scientific and Technical Information of China (English)

    LI Chao-jun; ZHU Pei-fang; LIU Zhao-hua; WANG Zheng-guo; YANG Cheng; CHEN Hai-bin; NING Xin; ZHOU Ji-hong; Chen Jian

    2006-01-01

    Objective: To explore the protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure (BUP).Methods: The hearing thresholds of the guinea pigs were assessed with auditory brainstem responses (ABR).The traumatic levels of tympanic membrane and ossicular chain were observed under stereo-microscope. The rate of outer hair cells (OHCs) loss was analyzed using a light microscope. The changes of guinea pigs protected with barrel and earplug were compared with those of the control group without any protection.Results: An important ABR threshold shift of the guinea pigs without any protection was detected from 8h to 14d after being exposed to BUP with a peak ranging from -64.5kPa to -69.3kPa (P<0.01). The rate of perforation of tympanic membrane reached 87.5 % and that of total OHCs loss was 19.46% + 5.38% at 14d after exposure. The guinea pigs protected with barrel and earplug had lower ABR threshold and total OHCs loss rate compared with the animals without any protection (P < 0.01 ). All of the tympanic membrane and ossicular chain of the protected animals maintained their integrities.Meanwhile, the guinea pigs protected with the barrel had lower ABR threshold and total OHCs loss rate than those with earplug (P<0.01).Conclusions: The earplug and barrel have protective effects against BUP-induced trauma on auditory organs of the guinea pigs and the protective effects of barrel are better than those of earplug.

  1. Blasting in underground mining

    OpenAIRE

    Doneva, Nikolinka; Despodov, Zoran; Mirakovski, Dejan; Hadzi-Nikolova, Marija; Mijalkovski, Stojance

    2015-01-01

    The long history of underground facilities gives us a lot of cognitions that we use in the choice of appropriate drilling and blasting parameters to obtain satisfactory results in underground facility constructions. In this paper are represent parts of those cognitions. Selection of an appropriate blast hole pattern, hole cut type, total quantity of explosives, initiation sequence and to the amount of explosive detonated per delay are crucial for successfully blasting in underground facilitie...

  2. Micro Shot Blasting of Machine Tools for Improving Surface Finish and Reducing Cutting Forces in Manufacturing

    OpenAIRE

    Vahey, James, (Thesis); Kennedy, David

    2005-01-01

    Micro blasting of cutting tips and tools is a very effective and reliable method of advancing the life of tools under the action of turning, milling, drilling, punching and cutting. This paper outlines the ways in which micro blasted tools, both coated and un coated have benefited from shot blasting and resulted in greater productivity, lower cutting forces, improved surface finish of the work pieces and less machine downtime. The process of micro blasting is discussed in the paper. Its effec...

  3. ORGANISATIONAL-TECHNOLOGICAL CHARACTERISTICS OF BLASTING WORKS ON THE GRIČ TUNNEL

    OpenAIRE

    2005-01-01

    The paper describes organisational-technological characteristics of blasting works during the excavation of the Grič Tunnel. The significance of blasting works during the excavation of the tunnel is shown through adjustment of blasting parameters taking into consideration the dynamics of the works, cost-effectiveness and influence of geological circumstances. Successfulness of blasting directly influences the subsequent tunnel excavation cycle both in terms of duration as well as eventually i...

  4. Experimental and Theoretical Study on Influence of Different Charging Structures on Blasting Vibration Energy

    OpenAIRE

    Wenbin Gu; Zhenxiong Wang; Jianghai Chen; Jianqing Liu; Ming Lu

    2015-01-01

    As an important parameter in blasting design, charging structure directly influences blasting effect. Due to complex conditions of this blasting and excavating engineering in Jiangsu, China, the authors carried out comparative researches with coupling structure, air-decoupling structure, and water-decoupling structure. After collecting, comparing, and analyzing produced signals on blasting vibration, the authors summarized that when proportional distances are the same, water-decoupling struct...

  5. Study on Damping Effect of Natural Cracks in Potential Unstable Rock Clear Blasting%天然裂缝在危岩体清除爆破中的减振效果研究

    Institute of Scientific and Technical Information of China (English)

    王胜波; 周传波; 袁红; 平雯

    2012-01-01

    分析巫山望霞危岩体削方爆破振动监测结果,发现爆破振动速度与常规经验公式计算得到的结果相差较大,利用ANSYS-AUTODYN数值模拟软件进行分析得知,危岩体的裂缝对爆破振动速度的减振效果达到33.9%,随着裂缝数目的增加,其减振效果也提高.该结果对同类危岩体治理工程的爆破参数设计提供了优化依据.%Data from blasting vibration monitoring of unstable rock mass at Wushan shows that the blasting vibration velocity is greatly different from the calculated vibration velocity with empirical formula. The software ANSYS— AUTODYN is used to simulate the blasting vibration. The simulated data shows that the blasting vibration is reduce 33.9% due to the cracks effect in the unstable rock mass. With the increasing of number of cracks, the vibration damping effect also increases. Results from this study provides optimized basis for blast parameters design in similar rock management.

  6. New gunpowder blasting

    International Nuclear Information System (INIS)

    This book introduces gunpowder blasting, which consists of ten chapters. It deals with conception of gunpowder on the history of gunpowder, difference between gunpowder and general materials and classification of gunpowder, reaction of gunpowder, shock wave and detonation, on properties, material velocity and structure, test method on gunpowder and an article processed with heat, gunpowder such as igniter charge, carlit and slurry gunpowder, propellant and an article processed with heat, blasting on basics and Bench cut, blasting operations and security blasting construction and using of gunpowder.

  7. Effects of Grit Blasting and Annealing on the High-Temperature Oxidation Behavior of Austenitic and Ferritic Fe-Cr Alloys

    Science.gov (United States)

    Proy, M.; Utrilla, M. V.; Otero, E.; Bouchaud, B.; Pedraza, F.

    2014-08-01

    Grit blasting (corundum) of an austenitic AISI 304 stainless steel (18Cr-8Ni) and of a low-alloy SA213 T22 ferritic steel (2.25Cr-1Mo) followed by annealing in argon resulted in enhanced outward diffusion of Cr, Mn, and Fe. Whereas 3 bar of blasting pressure allowed to grow more Cr2O3 and Mn x Cr3- x O4 spinel-rich scales, higher pressures gave rise to Fe2O3-enriched layers and were therefore disregarded. The effect of annealing pre-oxidation treatment on the isothermal oxidation resistance was subsequently evaluated for 48 h for both steels and the results were compared with their polished counterparts. The change of oxidation kinetics of the pre-oxidized 18Cr-8Ni samples at 850 °C was ascribed to the growth of a duplex Cr2O3/Mn x Cr3- x O4 scale that remained adherent to the substrate. Such a positive effect was less marked when considering the oxidation kinetics of the 2.25Cr-1Mo steel but a more compact and thinner Fe x Cr3- x O4 subscale grew at 650 °C compared to that of the polished samples. It appeared that the beneficial effect is very sensitive to the experimental blasting conditions. The input of Raman micro-spectroscopy was shown to be of ground importance in the precise identification of multiple oxide phases grown under the different conditions investigated in this study.

  8. Modelling Rock Blasting Considering Explosion Gas Penetration Using Discontinuous Deformation Analysis

    Science.gov (United States)

    Ning, Youjun; Yang, Jun; Ma, Guowei; Chen, Pengwan

    2011-07-01

    Explosion gas plays an important role in rock mass fragmentation and cast in rock blasting. In this technical note, the discontinuous deformation analysis method is extended for bench rock blasting by coupling the rock mass failure process and the penetration effect of the explosion gas based on a generalized artificial joint concept to model rock mass fracturing. By tracking the blast chamber evolution dynamically, instant explosion gas pressure is derived from the blast chamber volume using a simple polytropic gas pressure equation of state and loaded on the blast chamber wall. A bench blasting example is carried out. The blast chamber volume and pressure time histories are obtained. The rock failure and movement process in bench rock blasting is reproduced and analysed.

  9. The effect of nilotinib plus arsenic trioxide on the proliferation and differentiation of primary leukemic cells from patients with chronic myoloid leukemia in blast crisis

    OpenAIRE

    Wang, Wei; Lv, Fei-fei; DU, YAN; Li, Nannan; Chen, Yaling; Chen, Lihong

    2015-01-01

    Aim To determine the effects of arsenic trioxide (ATO) and nilotinib (AMN107, Tasigna) alone or in combination on the proliferation and differentiation of primary leukemic cells from patients with chronic myeloid leukemia in the blast crisis phase (CML-BC). Methods Cells were isolated from the bone marrow of CML-BC patients and were treated with 1 μM ATO and 5 nM nilotinib, either alone or in combination. Cell proliferation was evaluated using a MTT assay. Cell morphology and the content of h...

  10. Conceptual design and simulation analysis of thermal behaviors of TGR blast furnace and oxygen blast furnace

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Extensive use of carbon based fuel is the main inducement for global warming and more extreme weather.Reducing carbon dioxide emission and enhancing energy use is a common subject in steel industry.In the integrated steel plant,decreasing carbon dioxide emission must consider energy balance in the whole iron and steel works,and secondary energy must be actively utilized.As promising blast-furnaces,top gas recovery blast furnace(TGR-BF) and oxygen blast furnace have been investigated.In this paper,conceptual TGR blast furnace and oxygen blast furnace are proposed.Base on the idea of blast furnace gas de-CO2 circulating as reducing agent and the idea of pure oxygen blast decreasing the thermal reserve zone temperature,process modeling is conducted with ASPEN Plus.It is shown that the developed model reasonably describes the energy balance and mass balance feature of the furnace,and provides basic thermodynamic condition for furnaces.The effects of changes in different operation conditions are studied by sensitivity analysis and reference data from simulation.

  11. Analysis of key technologies and development of integrated digital processing system for cast blasting design

    Institute of Scientific and Technical Information of China (English)

    丁小华; 李克民; 肖双双; 狐为民

    2015-01-01

    Casting blast can greatly reduce the stripping cost and improve the production capacity of opencast coal mines. Key technologies including high bench blasting, inclined hole, millisecond blasting, pre-splitting blasting and casting blast parameters determination which have influence on the effect of casting blast have been researched with the combination of the ballistic theory and experience in mines. The integrated digital processing system of casting blast was developed in order to simplify the design process of casting blast, improve working efficiency and veracity of design result and comprehensively adopt the software programming method and the theory of casting blast. This system has achieved five functions, namely, the 3D visualization graphics management, the intelligent management of geological information, the intelligent design of casting blast, the analysis and prediction of the blasting effect and the automatic output of the design results. Long-term application in opencast coal mines has shown that research results can not only reduce the specific explosive consumption and improve the blasting effect, but also have high value of popularization and application.

  12. 毫秒延时爆破振动叠加作用的数值模拟研究%NUMERICAL SIMULATION RESEARCH ON VIBRATION SUPERPOSITION EFFECTS IN THE MILLISECOND DELAY BLASTING

    Institute of Scientific and Technical Information of China (English)

    苏波; 高可帅; 宋瑞富

    2012-01-01

    首先进行了单孔爆破地震波数值模拟,其波形变化规律与相关研究相吻合.在此基础上进行了两孔延时间隔为0~25ms的爆破振动波形叠加作用的数值模拟,并讨论了两种不同延时间隔理论的可行性和实用性.研究表明,即使延时间隔不足1/5倍主震周期,毫秒延时爆破的振速也低于齐发爆破的振速;当延时间隔约为1/2倍主震周期时,存在部分测点振速低于单孔爆破振速的现象,但由于爆破振动周期不规则变化,其降振的可靠性不高;当延时间隔大于地震波持续时间时,可避免前后地震波主震段叠加,从而将多孔毫秒延时爆破振速降低至单孔爆破的振速.%First of all, the single-hole blasting seismic wave was analyzed by numerical simulation method, the change law of its wave shape corresponded with the relative researches. Based on the single-hole blasting vibration analysis, milliseccnd blasting vibration wave-shape superposition effects were simulated with delay time intervals between 0 and 25 milliseconds, the feasibility and practicality of two different delay time interval theory were discussed. The results showed that vibration velocity caused by millisecond delay blasting was lower than that caused by simultaneous blasting, even though the delay time interval ,was less than 1/5 of main quake period, vibration velocities of partial measuring points caused by millisecond delay blasting were lower than those caused by single-hole blasting when the delay time interval was nearby 1/2 of main quake period, the reliability of decreasing vibration was not high because of the irregular vibration period; and the superposition of main quake segments was avoided when the delay time interval was longer than the duration of seismic wave so as to make vibration velocity caused by holes millisecond delay blasting reduce to the vibration velocity caused by the single-hole blasting.

  13. Experimental Studies of Mitigation Materials for Blast Induced Tbi

    Science.gov (United States)

    Alley, M. D.; Son, S. F.; Christou, G.; Goel, R.; Young, L.

    2009-12-01

    The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the material to reduce the damage caused by the blast. Several methods of energy transfer in blast wave flows are expected including: material interfaces with impedance mismatches, density changes in a given material, internal shearing, and particle fracture. Our hypothesis is that the greatest energy transfer within the obstructing material will yield the greatest mitigation effects to the blast. Sample configurations of foam were varied to introduce material interfaces and filler materials with varying densities and impedances (liquids and powders). The samples were dynamically loaded using a small scale blast produced by an explosive driven shock tube housing gram-scale explosive charges. The transmitted blast profiles were analyzed for variations in impulse characteristics and frequency components as compared to standard free field profiles. The results showed a rounding effect of the transmitted blast profile for all samples with the effects of the high density fillers surpassing all others tested. These results lead to a conclusion that low porosity, high density materials offer superior attenuation by reducing air blast features and spatially distributing the transmitted wave.

  14. Dry ice blasting for the conservation cleaning of metals

    NARCIS (Netherlands)

    R. van der Molen; I. Joosten; T. Beentjes; L. Megens

    2010-01-01

    This research was carried out to assess the feasibility of dry ice blasting as a replacement for solvent cleaning for the removal of organic layers from metal cultural heritage objects. The effects of dry ice blasting on test samples of aluminium, bronze and weathering steel were studied along with

  15. 爆破冲击波的生物影响效应研究进展%Research Progress of the Effect of Biological on Blasting Shock-wave

    Institute of Scientific and Technical Information of China (English)

    彭蜀君

    2012-01-01

    As the development of recent social, blasting method have widely applied in economic construc- tion, and people paid more and more attention to the follow-up question of blasting. Now Reviewing the effect of biological on blasting shock-wave, and proposing the relevant safety precautions.%随着现代社会的发展,爆破手段已广泛应用于经济建设中,人们对爆破产生的后续问题也越来越重视。综述了爆破产生的冲击波对周围生物的影响效应,并提出了相应的安全防护措施。

  16. β-氨基丁酸诱导水稻稻瘟病抗性对活性氧代谢的影响%Effects of β-Amino Butyric Acid Induced Rice Blast Resistance on Reactive Oxygen Metabolism

    Institute of Scientific and Technical Information of China (English)

    李莉; 郭晓丽; 刘晓梅; 温嘉伟; 张秀容; 孙辉; 赵宇; 任金平

    2009-01-01

    [Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly susceptible to disease as experimental material, the changes of catalase(CAT), and superoxide dismutase(SOD) and MDA activities in rice treated by BABA were investigated. [Result] In rice plants treated by BABA, the activities of CAT and SOD increased, meanwhile the MDA content also rose to some extent, resulting in the disease resistance to rice blast. [Conclusion] By influencing reactive oxygen metabolism, BABA endows rice plants with resistance to rice blast. BABA is safe to environment and has highly resistance-inducing capacity, it could be generalized in production.

  17. 基于未确知测度的爆破效果综合评价研究%STUDY ON COMPREHENSIVE EVALUATION OF THE BLASTING EFFECT BASED ON UNASCERTAINED MEASURE

    Institute of Scientific and Technical Information of China (English)

    陶铁军; 汪艮忠

    2012-01-01

    针对实际工程中评价爆破效果的因素指标不确定性问题,通过引入未确知测度理论,建立了基于未确知测度的爆破效果综合评价模型,并结合某露天铁矿深孔台阶爆破的实际情况,对爆破效果进行了基于未确知测度理论的综合评价.评价结果表明:基于未确知测度的爆破效果综合评价模型在各评价指标权重和识别准则的确定上,分别采用了信息熵和置信度识别准则,避免了模糊数学、层次分析法以及灰色关联理论等评判方法在这些方面的不足,使评价结果更具客观性;其评价指标可根据实际情况灵活选取,评价模型计算简单,评价结果能够为爆破工作者根据现场实际情况,适时调整爆破方案,为实现最优的爆破施工与管理提供决策依据.%In order to resolve the uncertainty problem of factor indicators of blasting effect evaluation for the actual project, the unascertained measure theory was introduced, and the comprehensive evaluation model of blasting effect based on the unascertained measure was built, then this model was used to evaluate the blasting effect of deep hole bench blasting in one open opit iron mine. The evaluation results show that the information entropy and confidence identifying criterion are respectively used to ascertain the evaluation index weight and identifying criterion in comprehensive evaluation model of the blasting effect based on unascertained measure, which avoided the shortcoming in other evaluation methods such as fuzzy mathematics, analytic hierarchy process as well as grey correlation and made the evaluation results more objective; and the evaluation index of the evaluation model can be selected flexibly according to actual situation and its calculation is simple, so the evaluation results can offer decision basis for blasting workers to adjust timely of blasting scheme according to the actual situation so as to achieve the optimal blasting working and

  18. Blast wave energy diagnostic.

    Science.gov (United States)

    Tierney, Thomas E; Tierney, Heidi E; Idzorek, George C; Watt, Robert G; Peterson, Robert R; Peterson, Darrell L; Fryer, Christopher L; Lopez, Mike R; Jones, Michael C; Sinars, Daniel; Rochau, Gregory A; Bailey, James E

    2008-10-01

    The distance radiation waves that supersonically propagate in optically thick, diffusive media are energy sensitive. A blast wave can form in a material when the initially diffusive, supersonic radiation wave becomes transonic. Under specific conditions, the blast wave is visible with radiography as a density perturbation. [Peterson et al., Phys. Plasmas 13, 056901 (2006)] showed that the time-integrated drive energy can be measured using blast wave positions with uncertainties less than 10% at the Z Facility. In some cases, direct measurements of energy loss through diagnostic holes are not possible with bolometric and x-ray radiometric diagnostics. Thus, radiography of high compression blast waves can serve as a complementary technique that provides time-integrated energy loss through apertures. In this paper, we use blast waves to characterize the energy emerging through a 2.4 mm aperture and show experimental results in comparison to simulations. PMID:19044574

  19. Relationship between orientation to a blast and pressure wave propagation inside the rat brain.

    Science.gov (United States)

    Chavko, Mikulas; Watanabe, Tomas; Adeeb, Saleena; Lankasky, Jason; Ahlers, Stephen T; McCarron, Richard M

    2011-01-30

    Exposure to a blast wave generated during an explosion may result in brain damage and related neurological impairments. Several mechanisms by which the primary blast wave can damage the brain have been proposed, including: (1) a direct effect of the shock wave on the brain causing tissue damage by skull flexure and propagation of stress and shear forces; and (2) an indirect transfer of kinetic energy from the blast, through large blood vessels and cerebrospinal fluid (CSF), to the central nervous system. To address a basic question related to the mechanisms of blast brain injury, pressure was measured inside the brains of rats exposed to a low level of blast (~35kPa), while positioned in three different orientations with respect to the primary blast wave; head facing blast, right side exposed to blast and head facing away from blast. Data show different patterns and durations of the pressure traces inside the brain, depending on the rat orientation to blast. Frontal exposures (head facing blast) resulted in pressure traces of higher amplitude and longer duration, suggesting direct transmission and reflection of the pressure inside the brain (dynamic pressure transfer). The pattern of the pressure wave inside the brain in the head facing away from blast exposures assumes contribution of the static pressure, similar to hydrodynamic pressure to the pressure wave inside the brain. PMID:21129403

  20. From blast wave to observation

    CERN Document Server

    van Eerten, H J

    2009-01-01

    Gamma-ray burst (GRB) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the GRB progenitor. We introduce a code to reconstruct spectra and light curves from arbitrary fluid configurations, making it especially suited to study the effects of fluid flows beyond those that can be described using analytical approximations. As a check and first application of our code we use it to fit the scaling coefficients of theoretical models of afterglow spectra. We extend earlier results of other authors to general circumburst density profiles. We rederive the physical parameters of GRB 970508 and compare with other authors. We also show the light curves resulting from a relativistic blast wave encountering a wind termination shock. From high resolution calculations we find that the observed transition from a stellar wind type light curve to an interstellar medium type light curve is smooth and without short-time trans...

  1. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    International Nuclear Information System (INIS)

    The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites

  2. Effect of the sand-blasting of edge peeling tools on the cutting forces and wear resistance

    OpenAIRE

    Labidi, Chafik; DENAUD, Louis; Nouveau, Corinne; Collet, Robert; Henry, Laurent

    2007-01-01

    International audience One of the major problems concerning tools of wood industry is nicks occurrence on the cutting edge. This phenomenon is accentuated by the small tool angle of most of the wood machining tools. The aim of this present study is to look if the geometry modifications of the cutting edge permit to decrease the weakness of the tools, especially in peeling process. For this, different sand-blasted tools were tested in laboratory peeling of beech. In addition, the adhesion o...

  3. Impact of complex blast waves on the human head: a computational study.

    Science.gov (United States)

    Tan, Long Bin; Chew, Fatt Siong; Tse, Kwong Ming; Chye Tan, Vincent Beng; Lee, Heow Pueh

    2014-12-01

    Head injuries due to complex blasts are not well examined because of limited published articles on the subject. Previous studies have analyzed head injuries due to impact from a single planar blast wave. Complex or concomitant blasts refer to impacts usually caused by more than a single blast source, whereby the blast waves may impact the head simultaneously or consecutively, depending on the locations and distances of the blast sources from the subject, their blast intensities, the sequence of detonations, as well as the effect of blast wave reflections from rigid walls. It is expected that such scenarios will result in more serious head injuries as compared to impact from a single blast wave due to the larger effective duration of the blast. In this paper, the utilization of a head-helmet model for blast impact analyses in Abaqus(TM) (Dassault Systemes, Singapore) is demonstrated. The model is validated against studies published in the literature. Results show that the skull is capable of transmitting the blast impact to cause high intracranial pressures (ICPs). In addition, the pressure wave from a frontal blast may enter through the sides of the helmet and wrap around the head to result in a second impact at the rear. This study recommended better protection at the sides and rear of the helmet through the use of foam pads so as to reduce wave entry into the helmet. The consecutive frontal blasts scenario resulted in higher ICPs compared with impact from a single frontal blast. This implied that blast impingement from an immediate subsequent pressure wave would increase severity of brain injury. For the unhelmeted head case, a peak ICP of 330 kPa is registered at the parietal lobe which exceeds the 235 kPa threshold for serious head injuries. The concurrent front and side blasts scenario yielded lower ICPs and skull stresses than the consecutive frontal blasts case. It is also revealed that the additional side blast would only significantly affect ICPs at

  4. SURFACE PREPARATION OF STEEL SUBSTRATES USING GRIT-BLASTING

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; D. J. Varacalle, Jr.; D. Deason; W. Rhodaberger; E. Sampson

    2005-05-01

    The primary purpose of grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents statistically designed experiments that were accomplished to investigate the effect of abrasives on roughness for A36/1020 steel. The experiments were conducted using a Box statistical design of experiment (SDE) approach. Three grit blasting parameters and their effect on the resultant substrate roughness were investigated. These include blast media, blast pressure, and working distance. The substrates were characterized for roughness using surface profilometry. These attributes were correlated with the changes in operating parameters. Twin-Wire Electric Arc (TWEA) coatings of aluminum and zinc/aluminum were deposited on the grit-blasted substrates. These coatings were then tested for bond strength. Bond strength studies were conducted utilizing a portable adhesion tester following ASTM standard D4541.

  5. Influence of millisecond time, charge length and detonation velocity on blasting vibration

    Institute of Scientific and Technical Information of China (English)

    陈士海; 吴建; 张子华

    2015-01-01

    The law of blasting vibration caused by blasting in rock is very complex. Traditional numerical methods cannot well characterize all the influencing factors in the blasting process. The effects of millisecond time, charge length and detonation velocity on the blasting vibration are discussed by analyzing the characteristics of vibration wave generated by finite length cylindrical charge. It is found that in multi-hole millisecond blasting, blasting vibration superimpositions will occur several times within a certain distance from the explosion source due to the propagation velocity difference of P-wave and S-wave generated by a short column charge. These superimpositions will locally enlarge the peak velocity of blasting vibration particle. The magnitude and scope of the enlargement are closely related to the millisecond time. Meanwhile, the particle vibration displacement characteristics of rock under long cylindrical charge is analyzed. The results show that blasting vibration effect would no longer increase when the charge length increases to a certain extent. This indicates that the traditional simple calculation method using the maximum charge weight per delay interval to predict the effect of blasting vibration is unreasonable. Besides, the effect of detonation velocity on blasting vibration is only limited in a certain velocity range. When detonation velocity is greater than a certain value, the detonation velocity almost makes no impact on blasting vibration.

  6. Proceedings: 17th Asilomar conference on fire and blast effects of nuclear weapons

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, R.G.; Meier, C.A. (eds.)

    1983-01-01

    The objective of the 1983 conference was to provide for the technical exchange of ideas relating to the science and technology of the immediate effects of nuclear weapon explosions. Separate abstracts were prepared for 39 of the papers.

  7. The effect of span length to height ratio of reinforced concrete slabs on pressure-impulse diagram with multiple failure modes under blast loading

    Directory of Open Access Journals (Sweden)

    Wang S.C.

    2012-08-01

    Full Text Available In this paper, two loosely coupled single degree of freedom (SDOF systems are used to generate pressure-impulse diagrams (P-I with the flexural and direct shear responses of one-way reinforced concrete slabs subjected to blast loading. The effect of span length to height ratio in P-I diagrams is investigated. The numerical calculation results indicate that a slab tends to fail in a direct shear mode if the blast load amplitude is high but of short duration. It tends to fail in flexural failure mode if load amplitude is relatively low and duration is relatively long. And the failure of the slab might be a combination of shear and flexural damage in the dynamic loading region. Based on numerical results, different failure modes are got with different the span length to height ratio on the P-I diagrams. Results indicate that there is only shear failure mode in the P-I diagrams when L/h 24.89, there are two damage mode in the P-I diagrams with flexure failure mode and flexure-shear failure mode. When 10.9 < L/h < 24.89, there are three damage modes in the P-I diagrams: shear failure mode, flexure failure mode and flexure-shear failure mode.

  8. Blast densification trials for oilsands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Port, A. [Klohn Crippen Berger Ltd., Vancouver, BC (Canada); Martens, S. [Klohn Crippen Berger Ltd., Calgary, AB (Canada); Eaton, T. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    The Shell Canada Muskeg River Mine External Tailings Facility (ETF) is an upstream constructed tailings facility located near Fort McMurray, Alberta. Raises have incrementally stepped out over the beach since construction of the starter dam and deposition within standing water has left some parts of the beach in a loose state. In order to assess the effectiveness of blast densification, a blast densification trial program that was conducted in 2006 at the ETF. The primary purpose of the test program was to determine the effectiveness of blast densification in tailings containing layers and zones of bitumen. The paper described the site characterization and explosive compaction trial program, with particular reference to test layout; drilling methodology; and blasting and timing sequence. The paper also described the instrumentation, including the seismographs; high pressure electric piezometers; low pressure electric piezometers; vibrating wire piezometers; inclinometers; settlement gauges; and surveys. Trial observations and post-trial observations were also presented. It was concluded that controlled blasting techniques could be used to safely induce liquefaction in localized areas within the tailings deposit, with a resulting increase in the tailings density. 5 refs., 1 tab., 14 figs.

  9. Laboratory blast wave driven instabilities

    Science.gov (United States)

    Kuranz, Carolyn

    2008-11-01

    This presentation discusses experiments involving the evolution of hydrodynamic instabilities in the laboratory under high-energy-density (HED) conditions. These instabilities are driven by blast waves, which occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. Instabilities evolving under HED conditions are relevant to astrophysics. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 μm plastic layer that is followed by a low-density foam layer. A blast wave structure similar to those in supernovae is created in the plastic layer. The blast wave crosses an interface having a 2D or 3D sinusoidal structure that serves as a seed perturbation for hydrodynamic instabilities. This produces unstable growth dominated by the Rayleigh-Taylor (RT) instability in the nonlinear regime. We have detected the interface structure under these conditions using x-ray backlighting. Recent advances in our diagnostic techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed or predicted by current simulations. The observed effect is potentially of great importance as a source of mass transport to places not anticipated by current theory and simulation. I will discuss the amount of mass in these spike extensions, the associated uncertainties, and hypotheses regarding their origin We also plan to show comparisons of experiments using single mode and multimode as well as 2D and 3D initial conditions. This work is sponsored by DOE/NNSA Research Grants DE-FG52-07NA28058 (Stewardship Sciences Academic Alliances) and DE-FG52-04NA00064 (National Laser User

  10. Methodology of Testing Shot Blasting Machines in Industrial Conditions

    Directory of Open Access Journals (Sweden)

    R. Wrona

    2012-04-01

    Full Text Available Shot blasting machines are widely used for automated surface treatment and finishing of castings. In shot blasting processes the stream of shots is generated and shaped by blasting turbines, making up a kinetic and dynamic system comprising a separating rotor, an adapting sleeve and a propelling rotor provided with blades. The shot blasting performance- i.e. the quality of shot treated surfaces depends on the actual design and operational parameters of the unit whilst the values of relevant parameters are associated with the geometry of turbine components and the level of its integration with the separator system. The circulation of the blasting medium becomes the integrating factor of the process line, starting from the hopper, through the propeller turbine, casting treatment, separation of contaminated abrasive mixture, to its recycling and reuse.Inferior quality of the abrasive agent (shot and insufficient purity of the abrasive mixture are responsible for low effectiveness of shot blasting. However, most practitioners fail to fully recognise the importance of proper diagnostics of the shot blasting process in industrial conditions. The wearing of major machine components and of the blasting agent and quality of shot treated surfaces are often misinterpreted, hence the need to take into account all factors involved in the process within the frame of a comprehensive methodology.This paper is an attempt to formulate and apply the available testing methods to the engineering practice in industrial conditions.

  11. Note: A table-top blast driven shock tube

    Science.gov (United States)

    Courtney, Michael W.; Courtney, Amy C.

    2010-12-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer that explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  12. A Table-top Blast Driven Shock Tube

    CERN Document Server

    Courtney, Michael; 10.1063/1.3518970

    2011-01-01

    The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer which explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

  13. Fracture analysis for controlled blasting demolition of reinforced concrete structures

    International Nuclear Information System (INIS)

    Toward establishing a design method for controlled blasting demolition used for the designed dismantling of large reinforced concrete (RC) structures, this study is intended to prove the overall suitability and efficiency of this method. The previous paper (Controlled Blasting for Demolition of Biological Shield Concrete Wall: Part 2) described an application of controlled blasting demolition to an inner part of the radioactive RC biological shield in the JPDR (Japan Power Demonstration Reactor). Through this experience, it was confirmed that the partial demolition of the structure was carried out safely and rationally using this method. In order to clarify the characteristics of blasting effect, an RC cylinder blasting test was performed and the results of this test were compared with analytical simulation of this test using the discrete element method (DEM) and the finite element method (FEM). This paper outlines the test, the analyses and the comparison. (author)

  14. Field experiment for blasting crater

    Institute of Scientific and Technical Information of China (English)

    YE Tu-qiang

    2008-01-01

    A series of single hole blasting crater experiments and a variable distance multi-hole simultaneous blasting experiment was carded in the Yunfu Troilite Mine, according to the Livingston blasting crater theory. We introduce in detail, our methodology of data collection and processing from our experiments. Based on the burying depth of the explosives, the blasting crater volume was fitted by the method of least squares and the characteristic curve of the blasting crater was obtained using the MATLAB software. From this third degree polynomial, we have derived the optimal burying depth, the critical burying depth and the optimal explosive specific charge of the blasting crater.

  15. Blast Diffusion by Different Shapes of Domes

    Directory of Open Access Journals (Sweden)

    Ram Ranjan Sahu

    2015-03-01

    Full Text Available Domes have been used since ancient times in constructions. These are effective structures in supporting loads for large span. Dome has an added advantage of having good looking in structural applications. Many shapes of domes are being used nowadays for residential, commercial, and industrial purposes. Specific purpose domes are also used for nuclear containment. Main threats to structures are from the bomb blast. Hence, domes too are to be designed to withstand effectively the pressure energy generated by the blast. A comparative theoretical study is proposed on the different shapes of domes having same weight and thickness. Various responses are estimated through numerical method after simulating blast and comparing their intensities.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.77-82, DOI:http://dx.doi.org/10.14429/dsj.65.6908

  16. Surface mine blasting near pressurized transmission pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Siskind, D.E.; Stagg, M.S.; Wiegand, J.E.; Schultz, D.L.

    1994-12-31

    The US Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17- to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pcts of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

  17. OsGF14e positively regulates panicle blast resistance in rice.

    Science.gov (United States)

    Liu, Qing; Yang, Jianyuan; Zhang, Shaohong; Zhao, Junliang; Feng, Aiqing; Yang, Tifeng; Wang, Xiaofei; Mao, Xingxue; Dong, Jingfang; Zhu, Xiaoyuan; Leung, Hei; Leach, Jan E; Liu, Bin

    2016-02-26

    Though GF14e has been reported to negatively regulate bacterial blight and sheath blight resistance in rice, its effect on panicle blast, the most destructive disease in rice is still unknown. In the present study, we identified that GF14e was highly expressed in panicles and was induced in panicles infected by blast pathogen. Overexpression of GF14e enhances resistance to panicle blast whereas silencing GF14e results in increased susceptibility to panicle blast, suggesting that GF14e plays a positive role in quantitative panicle blast resistance in rice. Our results also demonstrate that GF14e is regulated by WRKY71 and GF14e-mediated panicle blast resistance is related to activation of SA-dependent pathway and suppression of JA-dependent pathway. The functional confirmation of GF14e in panicle blast resistance makes it to be a promising target in molecular rice breeding. PMID:26851365

  18. Numerical Analysis of Dynamic Behavior of RC Slabs Under Blast Loading

    Institute of Scientific and Technical Information of China (English)

    DU Hao; LI Zhongxian

    2009-01-01

    In Order to reduce economic and life losses due to terrorism or accidental explosion threats,reinforced concrete(RC)slabs of buildings need to be designed or retrofitted to resist blast loading.In this paper the dynamic behavior Of RC slabs under blast loading and its influencing factors are studied.The numerical model of an RC slab subjected to blast loading is established using the explicit dynamic analysis software.Both the strain rate effect and the damage accumulation are taken into account in the material model.The dynamic responses of the RC slab subiected to blast loading are analyzed,and the influence of concrete strength,thickness and reinforcement ratio on the behavior of the RC slab under blast loading iS numerically investigated.Based on the numerical results.some principles for blast-resistant design and retrofitting are proposed to improve the behavior of the RC slab subjected to blast loading.

  19. 基于岩体爆破累积损伤效应的Hoek-Brown准则修正公式%Amended expressions of Hoek-Brown criterion based on blasting cumulative damage effects of rock mass

    Institute of Scientific and Technical Information of China (English)

    闫长斌; 李国权; 陈东亮; 刘振红; 刘建磊

    2011-01-01

    The disturbance and damage induced by excavation and blasting, especial blasting cumulative damage effects resulted from frequent blasting, will play down the integrity of rock mass, weaken the mechanical parameters of rock.mass and threaten the stability of rock engineering surely. Considered the blasting cumulative damage effects of rock mass, the shortages of Hoek-Brown criterion and its modified expressions were pointed out. The methods of obtaining the value of mb and s which could reflect the blasting cumulative damage effects, blasting disturbed state and the lowering degree of its mechanical parameters, were found by introducing integrity coefficient Kv and damage factor D. The cumulative expanded models of rock mass blasting damage were found with the baseline of rock mass sound velocity reducing ratio η and the models were used in the amended expressions of Hoek-Brown criterion, based on the relationship between sound velocity variation and blasting cumulative damage effects. The analysis of the amended expressions was carried out based on the simulative blasting tests in-situ and the data of sonic measurement. The research results show that the amended expressions of Hoek-Brown criterion taken blasting cumulative damage effects of rock mass into account are reasonable.%爆破开挖作业引起的扰动与损伤,特别是频繁爆破产生的累积损伤效应,必然导致岩体完整性降低,岩体力学参数弱化,从而威胁岩体工程稳定性.考虑岩体爆破损伤及其累积效应,指出了Hoek-Brown(赫克-布朗)准则及其改进公式的不足,引入完整性系数Kv和损伤因子D,建立了可以表征岩体爆破累积损伤效应、岩体爆破扰动状态及其力学参数弱化程度的mb和s的取值方法.基于声速变化与爆破累积损伤效应之间的联系,建立了以岩体声速降低率η为基准量的岩体爆破累积损伤扩展模型,并将该模型成功应用于提出的Hoek-Brown准则修正公式中.根据

  20. Technology for Geophysical Prospecting of Blasting and Grouting Effects of Bed Rocks%基岩爆破和注浆处理效果的物探检验技术研究

    Institute of Scientific and Technical Information of China (English)

    党如姣

    2012-01-01

    Bed rocks intrude into the seope of a shield-bored running tunnel of Shenzhen Metro. Blasting and grouting are carried out so as to ensure the successful driving of the shield. Geophysical prospecting, including high density resis- tivity method and Rayleigh wave method, is made to detect the effect of the blasting and grouting. In the paper, study is made on the mentioned geophysical prospecting methods. Conclusions drawn are as follows: 1 ) Quantitative analysis is achieved to some extent and the effects of the blasting and grouting are reflected by the resistivity and the transverse wave velocity. 2) Continuous monitoring and final evaluation of the effects of blasting and grouting are realized, which can provide reference for the blasting and grouting.%为了保证土压平衡盾构区间基岩经爆破处理和封闭注浆后的地层的气密性,采用高密度电阻率法与面波地震法相结合的方法,对隧道范围内的基岩爆破和注浆处理效果的物探检验技术进行研究。主要研究成果如下:1)在一定程度上实现了定量分析,将爆破和注浆施工质量具体地反映在电阻率值和横波速度数值上。2)实现了对爆破和注浆施工质量的连续监测和最终检验评价,对爆破和注浆施工有一定的指导作用。

  1. 75 FR 23589 - Safety Zones; Blasting Operations and Movement of Explosives, St. Marys River, Sault Sainte Marie...

    Science.gov (United States)

    2010-05-04

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zones; Blasting Operations and Movement of... ensure the safety of the maritime community during blasting and dredging operations. DATES: Effective... action is needed to ensure the public's safety during blasting and dredging operations. Delaying...

  2. Suppressive effects of mycoviral proteins encoded by Magnaporthe oryzae chrysovirus 1 strain A on conidial germination of the rice blast fungus.

    Science.gov (United States)

    Urayama, Syun-Ichi; Kimura, Yuri; Katoh, Yu; Ohta, Tomoko; Onozuka, Nobuya; Fukuhara, Toshiyuki; Arie, Tsutomu; Teraoka, Tohru; Komatsu, Ken; Moriyama, Hiromitsu

    2016-09-01

    Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is the causal agent of growth repression and attenuated virulence (hypovirulence) of the rice blast fungus, Magnaporthe oryzae. We previously revealed that heterologous expression of the MoCV1-A ORF4 protein resulted in cytological damage to the yeasts Saccharomyces cerevisiae and Cryptococcus neoformans. Since the ORF4 protein is one of the components of viral particles, we evaluated the inhibitory effects of the purified virus particle against the conidial germination of M. oryzae, and confirmed its suppressive effects. Recombinant MoCV1-A ORF4 protein produced in Pichia pastoris was also effective for suppression of conidial germination of M. oryzae. MoCV1-A ORF4 protein sequence showed significant similarity to 6 related mycoviral proteins; Botrysphaeria dothidea chrysovirus 1, two Fusarium graminearum viruses, Fusarium oxysporum f. sp. dianthi mycovirus 1, Penicillium janczewski chrysovirus and Agaricus bisporus virus 1 in the Chrysoviridae family. Multiple alignments of the ORF4-related protein sequences showed that their central regions (210-591 aa in MoCV1-A ORF4) are relatively conserved. Indeed, yeast transformants expressing the conserved central region of MoCV1-A ORF4 protein (325-575 aa) showed similar impaired growth phenotypes as those observed in yeasts expressing the full-length MoCV1-A ORF4 protein. These data suggest that the mycovirus itself and its encoded viral protein can be useful as anti-fungal proteins to control rice blast disease caused by M. oryzae and other pathogenic fungi. PMID:27329666

  3. Curved characteristics behind blast waves.

    Science.gov (United States)

    Laporte, O.; Chang, T. S.

    1972-01-01

    The behavior of nonisentropic flow behind a propagating blast wave is theoretically studied. Exact solutions, expressed in closed form in terms of elementary functions, are presented for three sets of curved characteristicseind a self-similar, strong blast wave.

  4. Mitigation of blast loadings on structures by an anti-blast plastic water wall

    Institute of Scientific and Technical Information of China (English)

    张力; 陈力; 方秦; 张亚栋

    2016-01-01

    Seven in-situ tests were carried out in far field to study the blast mitigation effect of a kind of water filled plastic wall. Test results show that the mitigation effect of water filled plastic wall is remarkable. The maximum reduction of peak reflected overpressure reaches up to 94.53%, as well as 36.3% of the minimum peak reflected overpressure reduction in the scaled distance ranging from 1.71 m/kg1/3 to 3.42 m/kg1/3. Parametric studies were also carried out. The effects of the scaled gauge height, water/charge scaled distance (the distance between the explosive charge and the water wall), water wall scaled height and water/structure scaled distance (the distance between the water wall and the structure) were systematically investigated and compared with the usual rigid anti-blast wall. It is concluded that these parameters affect the mitigation effects of plastic water wall on blast loadings significantly, which is basically consistent to the trend of usual rigid anti-blast wall. Some formulae are also derived based on the numerical and test results, providing a simple but reliable prediction model to evaluate the peak overpressure of mitigated blast loadings on the structures.

  5. Investigation of Ultrafast Laser-Driven Radiative Blast Waves

    International Nuclear Information System (INIS)

    We have examined the evolution of cylindrically symmetric blast waves produced by the deposition of femtosecond laser pulses in gas jets. In high-Z gases radiative effects become important. We observe the production of an ionization precursor ahead of the shock front and deceleration parameters below the adiabatic value of 1/2 (for a cylinder), an effect expected when the blast wave loses energy by radiative cooling. Despite significant radiative cooling, the blast waves do not appear to develop thin shell instabilities expected for strongly radiative waves. This is believed to be due to the stabilizing effect of a relatively thick blast wave shell resulting in part from electron thermal conduction effects

  6. Blast Loaded Aluminium Plates : Experiments and numerical simulations

    OpenAIRE

    Melby, Emil Arne; Eide, Hilde Olaug Stakvik

    2013-01-01

    Light and flexible protective constructions in aluminium could be subjected to a blast load. In this thesis the effect of blast loading on aluminium plates of the type 1050A ? H14 was studied through experiments and numerical simulations. The effect of fragmentation was idealized with predrilled holes. The thesis was written at the Structural Impact Laboratory (SIMLab) at NTNU in collaboration with the Norwegian Defence Estates Agency (NDEA).Tensile tests revealed a clearly anisotropic behavi...

  7. Powder blasting for three-dimensional microstructuring of glass

    OpenAIRE

    Belloy, E.; Sayah, A.; Gijs, M. A. M.

    2000-01-01

    We report on powder blasting as a promising technology for the three-dimensional structuring of brittle materials. We investigate the basic parameters of this process, which is based on the erosion of a masked substrate by a high-velocity eroding powder beam, using glass substrates. We study the effect of various parameters on the etching rate, like the powder velocity and the mask feature size, which induces geometrical effects to the erosion process. We introduce oblique powder blasting and...

  8. 立井直眼微差爆破模型试验振动测试与分析%Blasting vibration measurement and analyses of millisecond blasting models for vertical shaft blasting

    Institute of Scientific and Technical Information of China (English)

    马芹永; 袁璞; 张经双; 韩博

    2015-01-01

    为降低立井爆破施工的振动效应,以立井爆破中两圈直眼为原型,实施三种不同起爆延期的直眼微差爆破模型试验,并用UBOX-5016型爆破振动智能监测仪测试混凝土模型的爆破振动效应。实测爆破振动波表明,微差爆破可减少单段起爆药量、明显降低爆破振动效应;起爆延期25 ms时I段、Ⅱ段爆破振动波形彼此叠加,测点形成干扰降振效应,爆破峰值振动速度较小;起爆延期为50 ms时I段、Ⅲ段爆破振动波形彼此独立,峰值振动速度由单段起爆药量决定。竖向爆破振动波形频谱分析表明,微差爆破振动幅值明显低于齐发爆破,且波形复杂。微差爆破能显著降低爆破振动效应,主振频率较高。%Taking two-circle vertical blast holes in vertical shaft blasting as prototype,tests for three millisecond blasting models with two-circle vertical blast holes were conducted to investigate the way to reduce the blasting vibration effect of vertical shaft blasting construction.The blasting vibration effects of a concrete model was monitored with a blasting vibration intelligent monitor UBOX-5016.The actual blasting vibration indicated that blasting vibration effect is reduced significantly by millisecond blasting through reducing the maximum charge;when the detonation time delay is 25 ms,two blasting vibration waves of segment I and segment Ⅱ overlap each other and the actual peak blasting vibration velocity is smaller due to interference effect of vibration reduction;when the detonation time delay is 50 ms,two blasting vibration waves of segment I and segment Ⅲ are almost independent and the actual peak blasting vibration velocity depends on the maximum charge.Spectral analyses were implemented for verticals blasting vibrations of three millisecond blasting models.It was shown that the amplitude of millisecond blasting is much lower than that of simultaneous blasting and the waveform of

  9. Research on the influence of denotation at the end of the hole on bench blasting effect%孔底起爆对台阶爆破效果影响研究

    Institute of Scientific and Technical Information of China (English)

    于灯凯; 陈庆凯; 雷高; 柏奎杰; 张邵鹏; 李东东

    2015-01-01

    Theoretical analysis of the influence of explosive package placement on blasting effect is conducted and the mechanism of the improvement denotation from the end of the hole makes for blasting effect is elucidated .Field tests in mines are analyzed for the comparison of the schemes of denotation in the middle and at the end of the hole , and high speed cameras are used to collect data of the open-pit bench blasting process .After the processing of data by MAS,the curve of the displacement ,casting speed and casting direction of rock blocks from different sections of the bench slope varying with time variables is obtained ,revealing the influence regularities of denotation locations have on rock casting speed and direction and proving the advantage denotation at the end of the hole has in bench blasting .The loading efficiency is increased by 17 %at the bottom of blasted scraps by denotation at the end of the hole ,it being a solution to the insufficient looseness at the bottom of blasted scraps and loading efficiency .%通过起爆药包位置对爆破效果影响理论分析,说明孔底起爆提高爆破效果的作用机理。通过矿山现场试验,对中部起爆方案和孔底起爆方案进行分析,利用高速摄像机对露天台阶爆破过程进行数据采集;MAS软件对数据进行处理后,从台阶坡面最先移动位置,台阶坡面运动轮廓,测点速度随时间变化情况,得到了台阶坡面不同位置的岩块位移、抛掷速度和抛掷方向随时间的变化曲线,揭示了起爆点位置对岩石抛掷速度和方向的影响规律,证明了孔底起爆在台阶爆破中的优越性。孔底起爆使矿山爆堆底部的铲装效率增加了17%,解决了矿山爆堆底部松散性不足,铲装效率低的问题。

  10. Evaluation of efficiency of working time of equipment in blast furnace department

    OpenAIRE

    E. Kardas

    2012-01-01

    Purpose: The main aim of the paper is the evaluation of efficiency of working time of equipment in blast furnace department with the use of Overall Equipment Effectiveness (OEE) and PAMCO method.Design/methodology/approach: The investigation was made for blast furnace department in Polish steel plant. Two methods: OEE and PAMCO was used. The analysis covers the period of 7 years. The analysis was made based on different data: different types of time connected whit work of blast furnaces, inte...

  11. Vascular and inflammatory factors in the pathophysiology of blast-induced brain injury

    Directory of Open Access Journals (Sweden)

    Gregory A Elder

    2015-03-01

    Full Text Available Blast-related traumatic brain injury (TBI has received much recent attention because of its frequency in the conflicts in Iraq and Afghanistan. This renewed interest has led to a rapid expansion of clinical and animal studies related to blast. In humans, high-level blast exposure is associated with a prominent hemorrhagic component. In animal models, blast exerts a variety of effects on the nervous system including vascular and inflammatory effects that can be seen with even low-level blast exposures which produce minimal or no neuronal pathology. Acutely, blast exposure in animals causes prominent vasospasm and decreased cerebral blood flow along with blood-brain barrier breakdown and increased vascular permeability. Besides direct effects on the CNS, evidence supports a role for a thoracically mediated effect of blast whereby pressure waves transmitted through the systemic circulation damage the brain. Chronically, a vascular pathology has been observed that is associated with alterations of the vascular extracellular matrix. Sustained microglial and astroglial reactions occur after blast exposure. Markers of a central and peripheral inflammatory response are found for sustained periods after blast injury and include elevation of inflammatory cytokines and other inflammatory mediators. At low levels of blast exposure, a microvascular pathology has been observed in the presence of an otherwise normal brain parenchyma, suggesting that the vasculature may be selectively vulnerable to blast injury. Chronic immune activation in brain following vascular injury may lead to neurobehavioral changes in the absence of direct neuronal pathology. Strategies aimed at preventing or reversing vascular damage or modulating the immune response may improve the chronic neuropsychiatric symptoms associated with blast-related TBI.

  12. Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology

    OpenAIRE

    Yun Chen; Wei Huang; Shlomi Constantini

    2012-01-01

    A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the ope...

  13. Blasting Vibration Monitoring of Undercrossing Railway Tunnel Using Wireless Sensor Network

    OpenAIRE

    2015-01-01

    The construction blasting in a new tunnel will undoubtedly influence the structure of existing tunnel. In order to monitor the effect of the blast-induced vibration on the structure of existing tunnel, a wireless sensor network (WSN) was established, which included the blast vibration monitoring system and the wireless remote data acquisition system. An existing railway tunnel was monitored during the construction of a new tunnel in Shaanxi, China. Concrete strain and peak particle velocity (...

  14. Effect of bulk microstructure of commercially pure titanium on surface characteristics and fatigue properties after surface modification by sand blasting and acid-etching.

    Science.gov (United States)

    Medvedev, A E; Ng, H P; Lapovok, R; Estrin, Y; Lowe, T C; Anumalasetty, V N

    2016-04-01

    Surface modification techniques are widely used to enhance the biological response to the implant materials. These techniques generally create a roughened surface, effectively increasing the surface area thus promoting cell adhesion. However, a negative side effect is a higher susceptibility of a roughened surface to failure due to the presence of multiple stress concentrators. The purpose of the study reported here was to examine the effects of surface modification by sand blasting and acid-etching (SLA) on the microstructure and fatigue performance of coarse-grained and ultrafine-grained (UFG) commercially pure titanium. Finer grain sizes, produced by equal channel angular pressing, resulted in lower values of surface roughness in SLA-processed material. This effect was associated with greater resistance of the UFG structure to plastic deformation. The fatigue properties of UFG Ti were found to be superior to those of coarse-grained Ti and conventional Ti-6Al-4V, both before and after SLA-treatment. PMID:26703365

  15. Effect of surface finishing such as sand-blasting and CrAlN hard coatings on the cutting edge’s peeling tools’ wear resistance

    OpenAIRE

    Nouveau, Corinne; Labidi, Chafik; Collet, Robert; Benlatreche, Yacine; DJOUADI, Mohamed Abdou

    2009-01-01

    The authors would like to thank IonBond (Chassieu-France) who made the sand-blasting treatments and the Regional Council of Burgundy and CTBA (Wood and Furniture Technical Centre) for their financial support.

  16. The introduction of powder blasting for sensor and microsystem applications

    OpenAIRE

    Belloy, E.; Thurre, S.; Walckiers, E.; Sayah, A.; Gijs, M. A. M.

    2000-01-01

    We introduce powder blasting using a pressurised nozzle and a metallic mask as a new promising technology for microsystem fabrication. We study basic parameters of this powder blasting erosion process as well as mask-geometry effects on the erosion rate. We demonstrate the application potential of this technique in three important fields of microsystems research: (i) the realisation of microfluidic chips for biochemical separations, (ii) the micropatterning of composite hard magnetic layers f...

  17. Investigation on seismic signals for blasting in quarries

    OpenAIRE

    B. Pandula; J. Kondela; K. Holub

    2012-01-01

    Blasting operations generate seismic waves with different maximum velocity amplitudes and wide spectrum of frequencies. The intensity of seismic waves’ vibrations is proportional to the weight of the applied explosive. If the vibrations are sufficient in energy, surrounding buildings can be damaged or destroyed. Evaluating the negative effects of the blasting operations and quantification of the seismic safety is nowadays very actual and a challenging problem. The article presents the res...

  18. Blasting Effect Comparison of Different Spatial Position Relationship between Rock Strata Dip and Bench Slop%不同岩层倾向与台阶坡面位置关系下的爆破效果

    Institute of Scientific and Technical Information of China (English)

    丁一鸣; 池恩安; 张修玉; 潘玉忠

    2012-01-01

    In the open pit soil-rock blasting process,the blasting effect will have a direct impact on the project construction period,economic benefit and other processes. And various factors such as the structural surface of rock,bedding-joint ,air face,hole nets parameters restrict the blasting effect. Effect comparison and blasting experiment on different relationship of spatial position between rock strata dip and bench slop obtain the best position relationship between rock strata dip and bench slop,the hole parameter designs at each position,and the construction working points.%在露天土石方爆破作业中,爆破效果的好坏直接影响工程的工期、经济效益和其他工序的进行,而岩体的结构面、层理、临空面、孔网参数等多种因素制约着爆破效果.通过对某个平场工程爆破岩层倾向与台阶坡面不同空间位置关系所产生的不同爆破效果进行试验与对比,得出对层状岩体进行平场施工时岩层倾向与台阶坡面的最佳位置关系以及各个位置关系的孔网参数设计和施工作业要点.

  19. Blast wave mitigation by dry aqueous foams

    Science.gov (United States)

    Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

    2013-02-01

    This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

  20. Tests and Analyses of the Effect of Underwater Controlled Blasting Projects in Complex Environments%复杂环境水下控制爆破工程影响效应测试分析

    Institute of Scientific and Technical Information of China (English)

    刘更宁; 汤连生; 戚玉亮; 桑海涛

    2015-01-01

    As the effects of blasting vibrations from underwater construction blasting have increas-ingly gained attention,it is particularly important to conduct research to examine the behavior of underwater blasting vibrations.This paper combines the major foundation trench excavation pro-jects of the immersed tube section in immersed tunnel engineering with indoor and outdoor tes-ting of the bedrock,field tests of the dynamic blasting effects,theoretical analysis,and other comprehensive means to explore the effect of dynamic characteristics of underwater explosion shocks on adjacent land buildings and riverside embankments.The results show that (1 )com-pared with the peak pressure value of a seismic wave,shock wave pressures of drilling blasting in water are small under the shallow water conditions and their propagation speeds are not faster than seismic waves,and therefore,when considering the stability of the embankment and shore buildings,the effects of water shock waves can be ignored under certain circumstances;and (2) concerning blasting constructions in different regions,the maximum blast should be the mini-mum of each of the allowed maximum doses based on the distances from the blasting point to the protected objects.The above results will provide an important reference for similar projects.%结合某沉管隧道沉管段基槽开挖工程,采用爆破动态效应的现场测试、理论分析等综合手段,探索水下爆破水中冲击波和爆破地震波动对邻近建筑物的动态效应特性。研究表明:(1)与地震波的峰值压力值相比,浅水条件下钻孔爆破水中冲击波压力值较小,传播速度也没有地震波快,特定情况下,在考量岸边堤岸及岸边建筑物的稳定性时可以忽略水冲击波的影响;(2)对于不同区域爆破施工来说,应根据其距离被保护对象的远近,选择各允许最大药量中的最小值作为最大爆破控制药量。研究成果对类似工程具有一定的借鉴意义。

  1. Evaluation of space radius formed by blasting pressure with linear charges

    Institute of Scientific and Technical Information of China (English)

    LIN Da-neng; CHEN Shou-ru; XIE Sheng-quan

    2005-01-01

    Based on the mechanism analysis of space form caused by blasting with linear charges, elastic-plastic model of space form caused by blasting was established in this paper. In terms of state equation of blasting and the balance of quality, evaluation formula based on elastic-plastic to estimate space diameter caused by blasting with linear charges was given. The procedure structure of evaluation was introduced. We did 18 experiments on situ and compared experiments results with evaluation ones. They are correspondent very well. Then a new method of evaluating underground space diameters caused by blasting with linear charges was given. The method has more great guidance significance to the optimism plan of the new blasting technology that utilizes the explosion effect of the explosive to compact the soil to form the underground space.

  2. Interactions between Blast Waves and V-Shaped and Cone-Shaped Structures

    Science.gov (United States)

    Peng, W.; Zhang, Z. Y.; Gogos, G.; Gazonas, G.

    2011-09-01

    A 2-D numerical model of interactions between a blast wave and a V-shaped or a cone-shaped structure is developed. The model simulates the blast wave reflection from a V-shaped or a cone-shaped structure, the movement of the structure due to the blast impact and the induced shock wave behind the structure. Elliptic grid generation and coordinate transformation are utilized to solve the flow fields in the irregular physical domain. Different types of blast wave reflections, such as normal reflection, oblique reflection and Mach stem reflection, are captured by the numerical model. It is found that the reflected pressure and impulse transmitted to the structure decrease with the increase of incident angle. On the other hand, with the increase of incident angle, the effects of fluid structure interactions (FSI) in reducing the blast loads decreases. The FSI coupled with oblique or Mach stem reflection improves the blast wave mitigation.

  3. Control technology for crystalline silica exposures in construction: wet abrasive blasting.

    Science.gov (United States)

    Golla, Vijay; Heitbrink, William

    2004-03-01

    This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying aggregate. In this process a wet sand mix comprised of 80% dry sand and 20% water was used. Sampling and analysis revealed that the geometric mean respirable quartz concentration was 0.2 mg/m(3) for workers conducting abrasive blasting and 0.06 mg/m(3) for helpers. When abrasive blasting was conducted in areas that apparently had reduced natural ventilation, dust exposures appeared to increase. When compared with other published data, this case study suggests that wet abrasive blasting causes less exposure to crystalline silica than dry abrasive blasting. PMID:15204868

  4. Abrasive blasting technology for decontamination of the inner surface of steam generator tubes

    International Nuclear Information System (INIS)

    The inner surfaces of bundled inconel tubes from steam generators in South Korean nuclear power plants are contaminated with cobalt and abrasive blasting equipment has been developed to efficiently remove the cobalt. The principal parameters related to the efficient removal using this equipment are the type of abrasive, the distance from the nozzle, and the blasting time. Preliminary tests were performed using oxidized inconel samples which enabled the simulation of cobalt removal from the radioactive inconel samples. The oxygen in the oxidized samples and the cobalt in the radioactive inconel were removed more effectively using the blasting distance, blasting time, and a silicon carbide abrasive. Using the developed abrasive blasting equipment, the optimum decontamination conditions for radioactive inconel samples were blasting for more than 6 minutes using silicon carbides under 5 atmospheric pressures

  5. Blast Load Response of Steel Sandwich Panels with Liquid Encasement

    Energy Technology Data Exchange (ETDEWEB)

    Dale Karr; Marc Perlin; Benjamin Langhorst; Henry Chu

    2009-10-01

    We describe an experimental investigation of the response of hybrid blast panels for protection from explosive and impact forces. The fundamental notion is to dissipate, absorb, and redirect energy through plastic collapse, viscous dissipation, and inter-particle forces of liquid placed in sub-structural compartments. The panels are designed to absorb energy from an impact or air blast by elastic-plastic collapse of the panel substructure that includes fluid-filled cavities. The fluid contributes to blast effects mitigation by providing increased initial mass and resistance, by dissipation of energy through viscosity and fluid flow, and by redirecting the momentum that is imparted to the system from the impact and blast impulse pressures. Failure and deformation mechanisms of the panels are described.

  6. The Control of the Underwater Blasting Vibration Effect in Complex Environment%复杂环境下水下爆破振动效应控制技术

    Institute of Scientific and Technical Information of China (English)

    王洪刚; 王洪强; 陈郁华; 刘昌邦

    2012-01-01

    混凝土浇筑施工期间,对爆破振动安全要求较高.在莆田LNG码头施工过程中,为了减少爆破振动对周边建筑物以及新浇筑混凝土罐体的影响,采取了减振孔、改变装药结构等减振措施.通过水下爆破实际应用,证明减振孔、改变装药结构等能够有效地减少爆破对新浇筑混凝土罐体的影响.%During the construction of concrete pouring, the requirement is high to vibration safety. In Putian LNG-container pier, shock absorption holes and changing charge structure were used to decrease the effect of the blasting vibration to the surrounding buildings and the new pouring concrete. Through the practical application in the underwater blasting, shock absorption holes and changing charge structure can effectively decrease the influence of blasting.

  7. Influence of wind effects on collapsing process of a chimney in blasting%爆破拆除烟囱倒塌过程中风效应影响研究

    Institute of Scientific and Technical Information of China (English)

    张宪堂; 王兆东; 王洪立; 王来

    2013-01-01

    在烟囱爆破拆除倒塌过程中,不同形式的风可使烟囱产生顺风向效应及横风向效应.横风向效应又包括横风向旋涡脱落及共振效应、横风向空气动力失稳.烟囱在风的长期作用下会发生失稳倾斜.揭示了爆破拆除过程中烟囱由于风振影响而发生倾斜、失稳的机理,分析了不同风向的三类风效应对爆破拆除时烟囱倒塌方向发生偏移的影响.根据分析计算结果可得,纵向风振影响最为显著,静力风效应影响相对较小,横向风振产生影响随机性较强.同时作者得出了爆破拆除烟囱时考虑风效应影响需采取的相应技术手段和措施.%In blasting demolition process of a chimney,along wind effect and across wind one are produced on the chimney under wind loads.The effect of across wind includes horizontal wind direction swirl,resonance effect and air dynamic destabilizing in horizontal wind direction.The long time action of wind load on a chimney during blasting demolition leads to sloping and destabilizing.The mechanism of sloping and destabilizing of a chimney due to windinduced vibration in its blasting demolition process was presented,and the deviations of the chimney collapsing direction during blasting demolition as results of three kinds of wind effect in different directions were analyzed.It was shown from the calculation results that the influence of along wind resonance is significant,the static wind effect is relatively small,and the influence of across wind resonance has a little stronger randomness.Also,the relevant technological measures needed considering the effect of wind in blasting demolition process of a chimney were obtained.

  8. A discrete particle approach to simulate the combined effect of blast and sand impact loading of steel plates

    Science.gov (United States)

    Børvik, T.; Olovsson, L.; Hanssen, A. G.; Dharmasena, K. P.; Hansson, H.; Wadley, H. N. G.

    2011-05-01

    The structural response of a stainless steel plate subjected to the combined blast and sand impact loading from a buried charge has been investigated using a fully coupled approach in which a discrete particle method is used to determine the load due to the high explosive detonation products, the air shock and the sand, and a finite element method predicts the plate deflection. The discrete particle method is based on rigid, spherical particles that transfer forces between each other during collisions. This method, which is based on a Lagrangian formulation, has several advantages over coupled Lagrangian-Eulerian approaches as both advection errors and severe contact problems are avoided. The method has been validated against experimental tests where spherical 150 g C-4 charges were detonated at various stand-off distances from square, edge-clamped 3.4 mm thick AL-6XN stainless steel plates. The experiments were carried out for a bare charge, a charge enclosed in dry sand and a charge enclosed in fully saturated wet sand. The particle-based method is able to describe the physical interactions between the explosive reaction products and soil particles leading to a realistic prediction of the sand ejecta speed and momentum. Good quantitative agreement between the experimental and predicted deformation response of the plates is also obtained.

  9. EVALUATION OF THE THIXOTROPY OF OIL-WELL CEMENTS USED FOR CEMENTING LOST CIRCULATION ZONES: EFFECT OF PLASTER AND BLAST FURNACE SLAG

    Directory of Open Access Journals (Sweden)

    T. Bouziani

    2015-08-01

    Full Text Available Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped.Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement with the plaster, using a viscometer with coaxial cylinder (couette type. Moreover, the effect of blast furnace slag (LHF on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally can produce mixes with higher and more stable thixotropy than the class G cement (from importation, which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster.

  10. The enhancement effect of pre-reduction using zero-valent iron on the solidification of chromite ore processing residue by blast furnace slag and calcium hydroxide.

    Science.gov (United States)

    Li, Jinchunzi; Chen, Zhonglin; Shen, Jimin; Wang, Binyuan; Fan, Leitao

    2015-09-01

    A bench scale study was performed to assess the effectiveness of the solidification of chromite ore processing residue (COPR) by blast furnace slag and calcium hydroxide, and investigate the enhancement effect of pre-reduction using zero-valent iron (ZVI) on the solidification treatment. The degree of Cr immobilization was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) as well as the solid waste-extraction procedure for leaching toxicity-sulfuric acid & nitric acid method (Chinese standard HJ/T299-2007). Strength tests and semi-dynamic leaching tests were implemented to investigate the potential for reusing the final treatment product as a readily available construction material. The experimental results showed that the performance of pre-reduction/solidification (S/S) was superior to that of solidification alone. After pre-reduction, all of the S/S treated COPR samples met the TCLP limit for total Cr (5 mg L(-1)), whereas the samples with a COPR content below 40% met the pollution control limit of bricks and building block products (Chinese standard HJ/T 301-2007) produced with COPR for total Cr (0.3 mg L(-1)). At the same time, all of the S/S treated specimens tested were suitable for utilization at certain levels. PMID:25929874

  11. Programmable Grit-Blasting System

    Science.gov (United States)

    Burley, Richard K.

    1988-01-01

    In programmable grit-blasting system undergoing design, controller moves blasting head to precise positions to shape or remove welding defects from parts. Controller holds head in position for preset dwell time and moves head to new position along predetermined path. Position of articulated head established by pair of servomotors according to programmed signals from controller. Head similar to video borescope. Used to remove welding defects in blind holes. Suited for repetitive production operations in grit-blast box.

  12. Blasting of broken marble zones

    OpenAIRE

    Dambov, Risto; Stojceski, Igor; Dambov, Ilija

    2015-01-01

    On receipt of marble blocks appear deformed zones with presence of cracks and other deformities and very small cracks with different azimuth in the rocky massif. The fastest and economical way to bring this zone are removed by applying the methods of blasting. Before blasting, these tables - zones are limited by the block, making the cuts with diamond wire because explosive action may cause of surrounding quality marble blocks. Keywords: blasting, crashed zones, cracks, marble ...

  13. Development and Application of Blast Casting Technique in Large-Scale Surface Mines: A Case Study of Heidaigou Surface Coal Mine in China

    OpenAIRE

    Li Ma; Kemin Li; Xiaohua Ding; Hongge Peng; Shuangshuang Xiao

    2016-01-01

    Blast casting is a high-efficiency technique applied in surface mines for overburden removal and results in stripping cost savings. According to ballistic theory and center-of-mass frame basic movement principles, key factors influencing blast casting effect were analyzed, which include bench height and mining panel width, inclined angle of blast holes, explosive unit consumption (EUC), delay-time interval, presplitting, and blast hole pattern parameters. An intelligent design software was de...

  14. 岩质边坡爆破振动速度的高程放大效应研究%ELEVATION AMPLIFICATION EFFECT OF BLASTING VIBRATION VELOCITY IN ROCK SLOPE

    Institute of Scientific and Technical Information of China (English)

    陈明; 卢文波; 李鹏; 刘美山; 周创兵; 赵根

    2011-01-01

    岩质边坡爆破振动的高程放大效应是边坡上振动速度传播规律的重要研究内容之一.基于岩质边坡爆破振动高程响应机制的理论分析以及边坡开挖爆破振动的数值模拟与实例分析,研究边坡爆破振动速度的高程放大效应.结果表明,边坡爆破振动速度的高程放大效应是在一定的条件下产生的,受爆破振动荷载特性及边坡坡形等因素的影响.爆破振动荷载作用下,边坡坡面不同高程台阶岩体结构的自振主频率处于爆破振动荷载主频带范围内,台阶部位岩体结构的振动响应会产生"鞭梢效应",导致台阶部位岩体振动速度放大.在边坡坡形骤变、坡度增大时,边坡上一级台阶岩体的振动速度可大于下一级台阶岩体的振动速度,产生显著的振动速度高程放大效应.坡形相近的条件下,台阶坡脚处的振动速度随高程的增加逐渐减小,不出现振动速度高程放大效应."鞭梢效应"影响下,边坡台阶边沿的振动速度较大,但应力、应变较同高程台阶坡脚处的小,边沿部位的振动速度不适宜评价边坡的稳定性.%Elevation amplification effect of blasting vibration is an important study content of vibration propagation law on rock slope. Based on the theoretical analysis of elevation response mechanism on rock slope, numerical simulation of blasting vibration induced by slope excavation and measured data analysis, the blasting vibration elevation amplification effect has been studied. The results indicate that the blasting vibration elevation amplification effect occurs under some conditions and it is affected by factors such as the property of blasting vibration and the slope form. Under the blasting load, when the natural frequencies of different slope benches correspond with the main frequency band of blast load, the"whiplash effects" are caused in rock structures of the slope benches and the vibrations are amplified. While slope form

  15. DISCUSSION ABOUT EFFECT OF ORGANIZATION AND COORDINATION ON SAFETY SUPERVISION OF BLASTING ENGINEERING%浅谈组织协调在爆破安全监理中的作用

    Institute of Scientific and Technical Information of China (English)

    张道振; 屠欢根; 李运喜; 高啸

    2011-01-01

    Based on the definition of organization and coordination. the specific characteristics of blasting engineering and the risk of safe supervision were analyzed. The basic principles, processes, specific methods and techniques of organization and coordination were discussed by theory of organizational behavior and views of project management. How supervision engineers use effective measures of organization and coordination to develop blasting safety supervision was analyzed, which provide reference for the workers who are engaged in blasting safety supervision.%从组织协调的定义出发,分析爆破工程项目特点、安全监理的风险责任.文中运用组织行为学的理论及项目管理学观点,论述了组织协调的基本原理、过程、特定的方法和技巧等.对监理工程师如何采用组织协调的有效手段开展爆破安全监理工作进行深入分析,为从事爆破安全监理的工作者提供参考.

  16. Electromagnetic emissions during rock blasting

    Science.gov (United States)

    O'Keefe, S. G.; Thiel, D. V.

    1991-05-01

    Radio emissions during quarry blasting have been recorded in the audio frequency band. Three distinct mechanisms are suggested to explain the observed results; rock fracture at the time of the explosion, charged rocks discharging on impact with the pit floor and micro-fracture of the remaining rock wall due to pressure adjustment of the bench behind the blast. The last mechanism was evident by a train of discrete impulses recorded for up to one minute after the blast. It is assumed that during this time the rock behind the blast was subjected to a significant change in pressure. This may be related to ELF observations during earthquakes.

  17. 切缝药包不耦合装药爆破爆生裂纹动态断裂效应的试验研究%EXPERIMENTAL STUDY OF DYNAMIC FRACTURE EFFECT OF BLASTING CRACK IN SLOTTED CARTRIDGE DECOUPLING CHARGE BLASTING

    Institute of Scientific and Technical Information of China (English)

    杨仁树; 王雁冰

    2013-01-01

      利用爆炸加载数字激光动态焦散线试验系统,对不同装药结构爆破爆生裂纹动态断裂效应进行分析,研究切缝药包的定向断裂控制爆破机制,比较爆生主裂纹和次裂纹动态能量释放率的差异。结果表明:不耦合系数α1=1.67时,切缝药包爆破效果最理想;爆生主裂纹的扩展速度、动态应力强度因子随时间总体呈振荡下降的趋势,在扩展过程的中后期达到一个较小的峰值;橡皮泥介质作为炸药爆炸产物与炮孔壁间的缓冲层,传能效果良好;次裂纹尖端的动态能量释放率数值整体上小于2条主裂纹。%  Explosion load test system of digital laser dynamic caustics is used to analyze the dynamic fracture effect of blasting crack with different charging structures. Mechanism of directional fracture blasting with slotted cartridge is studied and the difference of dynamic energy release rate between principal crack and secondary crack is compared. The results show that the blasting effect is best when the decoupling coefficient α1 = 1.67. The propagation velocity and dynamic stress intensity factor of principal crack show a downward trend in the mass, and is up to a smaller peak in the mid- and late-expansion processes. As the buffer layer between explosive product and blasting hole wall,the plasticine medium transfers energy well. The dynamic energy release rate values of secondary crack as a whole is less than that of two principal cracks.

  18. Summary of the Mechanism of Directional Fracture Controlled Blasting%定向断裂控制爆破机理综述

    Institute of Scientific and Technical Information of China (English)

    张志呈

    2000-01-01

    作者从理论上将光面爆破、预裂爆破,切槽爆破、切缝药包爆破,聚能药包爆破等常用控制爆破统称为定向断裂控制爆破。综述了爆破破裂过程中爆生气体作用和应力波作用,重点分析了圆形炮孔爆破的成缝机理。%The author refers smooth blast,presplitting blast,cutting blast,cracking charge blast and cumulative charge blast to as directional fracture controlled blast in theory.The effects of explosion gas and stress wave in fracture process of blasting are described with emphasis on the analysis of cracking mechanism of hole blasting.

  19. Blasting Impact by the Construction of an Underground Research Tunnel in KAERI

    International Nuclear Information System (INIS)

    The underground research tunnel, which is under construction in KAERI for the validation of HLW disposal system, is excavated by drill and blasting method using high-explosives. In order not to disturb the operation at the research facilities such as HANARO reactor, it is critical to develop a blasting design , which will not influence on the facilities, even though several tens of explosives are detonated almost simultaneously. To develop a reasonable blasting design, a test blasting at the site should be performed. A preliminary analysis for predicting the expected vibration and noise by the blasting for the construction of the underground research tunnel was performed using a typical empirical equation. From the study, a blasting design could be developed not to influence on the major research facilities in KAERI. For the validation of the blasting design, a test blasting was carried out at the site and the parameters of vibration equation could be determined using the measured data during the test blasting. Using the equation, it was possible to predict the vibration at different locations at KAERI and to conclude that the blasting design would meet the design criteria at the major facilities in KAERI. The study would verify the applicability of blasting method for the construction of a research tunnel in a rock mass and that would help the design and construction of large scale underground research laboratory, which might be carried out in the future. It is also meaningful to accumulate technical experience for enhancing the reliability and effectiveness of the design and construction of the HLW disposal repository, which will be constructed in deep underground by drill and blasting technique

  20. Effect of TiO2 Content on the Crystallization Behavior of Titanium-Bearing Blast Furnace Slag

    Science.gov (United States)

    Hu, Meilong; Wei, Ruirui; Yin, Fangqing; Liu, Lu; Deng, Qingyu

    2016-09-01

    The content of TiO2 has an important influence on both the basic structure and the crystallization behavior of titanium-bearing blast furnace (BF) slag. The results of thermodynamic calculations show that, when the mass content of TiO2 is smaller than 25%, CaTiO3 increases as the content of TiO2 increases. However, when the TiO2 content is more than 25%, the CaTiO3 content decreases and TiO2 gradually increases. The results of a confocal laser scanning microscopy (CLSM) experiment show that, when the TiO2 mass content is 10%, Ca2MgSi2O7 and Ca2Al2SiO7 are the main crystallized phases resulting from the molten slag. Furthermore, when the TiO2 mass content is 20%, CaMgSi2O6, Ca(Ti,Mg,Al)(Si,Al)2O7 and dendrite CaTiO3 are the crystallized phases, while when the TiO2 mass content increases to 30%, CaTiO3 is the sole phase. The discrepancy between the CLSM results and the thermodynamic calculations occurs mainly due to the high melting point of the titanium-bearing BF slag. During the cooling process for the molten slag, CaTiO3 is crystallized first, due to its high crystallization temperature. Furthermore, the molten slag is solidified in its entirety before the other phases crystallize.

  1. Effect of Al2O3 Addition on the Precipitated Phase Transformation in Ti-Bearing Blast Furnace Slags

    Science.gov (United States)

    Li, Zhongmin; Li, Jinfu; Sun, Yongqi; Seetharaman, Seshadri; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2016-04-01

    The present paper aims to provide a fundamental understanding on phase change of Ti-enriched crystalline phase induced by Al2O3 addition in Ti-bearing blast furnace slags with different basicities using Single Hot Thermocouple Technique and X-ray Diffraction. The results showed that an increase in the Al2O3 content led to phase change from rutile or perovskite to Mg3Al4Ti8O25 and prompted crystallization of the slags with basicity of 0.60 and 0.75, whereas only CaTiO3 was precipitated at a basicity of 0.95. Both thermodynamic and kinetic analyses were conducted to study the slag crystallization, which would throw light on phase change and enhanced crystallization. To further reveal the relationship with Al2O3 addition on slag structure and crystallization, Fourier transform infrared spectroscopy and magic angle spinning-nuclear magnetic resonance were adopted, with AlO4 tetrahedra and AlO6 octahedra observed in the slag. For slags with the basicity of 0.60 and 0.75, AlO6 octahedron, which was suggested to induce the phase change from TiO2 or CaTiO3 to Mg3Al4Ti8O25, was detected at high Al2O3 content. On the other hand, in slags with the basicity of 0.95, abundant Ca2+ may be connected to TiO6 octahedra, resulting in CaTiO3 formation.

  2. Characterization of viscoelastic materials for low-magnitude blast mitigation

    Science.gov (United States)

    Bartyczak, S.; Mock, W.

    2014-05-01

    Recent research indicates that exposure to low amplitude blast waves, such as IED detonation or multiple firings of a weapon, causes damage to brain tissue resulting in Traumatic Brain Injury (TBI) and Post Traumatic Stress Disorder (PTSD). Current combat helmets are not sufficiently protecting warfighters from this danger and the effects are debilitating, costly, and long-lasting. The objective of the present work is to evaluate the blast mitigating behavior of current helmet materials and new materials designed for blast mitigation using a test fixture recently developed at the Naval Surface Warfare Center Dahlgren Division for use with an existing gas gun. The 40-mm-bore gas gun was used as a shock tube to generate blast waves (ranging from 0.5 to 2 bar) in the test fixture mounted on the gun muzzle. A fast opening valve was used to release helium gas from the breech which formed into a blast wave and impacted instrumented targets in the test fixture. Blast attenuation of selected materials was determined through the measurement of stress data in front of and behind the target. Materials evaluated in this research include polyurethane foam from currently fielded US Army and Marine Corps helmets, polyurea 1000, and three hardnesses of Sorbothane (48, 58, and 70 durometer, Shore 00). Polyurea 1000 and 6061-T6 aluminum were used to calibrate the stress gauges.

  3. Comprehensive Numerical Modeling of the Blast Furnace Ironmaking Process

    Science.gov (United States)

    Zhou, Chenn; Tang, Guangwu; Wang, Jichao; Fu, Dong; Okosun, Tyamo; Silaen, Armin; Wu, Bin

    2016-05-01

    Blast furnaces are counter-current chemical reactors, widely utilized in the ironmaking industry. Hot reduction gases injected from lower regions of the furnace ascend, reacting with the descending burden. Through this reaction process, iron ore is reduced into liquid iron that is tapped from the furnace hearth. Due to the extremely harsh environment inside the blast furnace, it is difficult to measure or observe internal phenomena during operation. Through the collaboration between steel companies and the Center for Innovation through Visualization and Simulation, multiple computational fluid dynamics (CFD) models have been developed to simulate the complex multiphase reacting flow in the three regions of the furnace, the shaft, the raceway, and the hearth. The models have been used effectively to troubleshoot and optimize blast furnace operations. In addition, the CFD models have been integrated with virtual reality. An interactive virtual blast furnace has been developed for training purpose. This paper summarizes the developments and applications of blast furnace CFD models and the virtual blast furnace.

  4. Control of blast overpressure and vibrations at the Underground Research Laboratory

    International Nuclear Information System (INIS)

    AECL Research (AECL) has constructed an Underground Research Laboratory (URL) as a facility for research and development in the Canadian Nuclear Fuel Waste Management Program. The objectives of the program are to develop and evaluate the technology to ensure safe, permanent disposal of Canada's nuclear fuel waste. Several multidisciplinary experiments and engineering demonstrations are planned for the URL over the next ten years. In 1989, AECL excavated a test room for the Buffer/Container Experiment at the 240 Level. The blasts were designed to limit vibration and overpressure damage because the excavation was located close to existing furnishings and services that were very susceptible to blast-induced vibration and overpressure. An experimental room, which contained sensitive instrumentation, was located within 30 m of the initial blasts. A concrete floor slab, timber curtains and a bulkhead were installed to protect furnishings and services from fly-rock and overpressure. Five of the initial blasts were monitored. This paper describes the results of the monitoring program and the effectiveness of the blast design, floor slab and timber curtains and bulkhead in reducing blast overpressure and vibrations at the blast site. It is shown that greater than a 20-fold reduction in both blast vibrations and air overpressures can be achieved with specific combinations of blast design, installation of timber curtains and construction of a concrete floor slab

  5. Trend analysis and comparison of basic parameters for tunnel blast design models

    Institute of Scientific and Technical Information of China (English)

    Khalili Soroush; Yavary Mehdi; Ebrahimabadi Arash

    2015-01-01

    One of the most important factors influencing on a tunnel blast efficiency is the proper design of blasting pattern. Among blasting parameters, blasthole diameter and tunnel face area are more significant so that any change in these parameters could finally affect on specific charge and specific drilling. There are mainly two groups of methods for tunnel blast design categorized based on the parallel cuts and angular cuts. In this research, a software for tunnel blast design was developed to analyze the effect and sensi-tiveness of blasthole diameter and the tunnel face area on blasting results in different blast design mod-els. Using the software, it is quickly possible to determine specific charge, specific drilling and number of blastholes for each blast design model. The relations between both of blasthole diameters and the tunnel face area with the above parameters in different blast design models were then investigated to yield a set of equations with the highest correlations to compare the methods. The results showed that angular method requires more blasthole numbers than parallel method in similar condition (blasthole diameter and tunnel face area). Moreover, the specific charge values yielded by the two methods are approximately the same and very close together.

  6. Inhibition Effect of Antagonistic Fungal Strain BOS-013 against the Pathogen of Rice Blast ( Pyricularia oryzae)%拮抗真菌菌株BOS-013对稻瘟病菌的抑制作用

    Institute of Scientific and Technical Information of China (English)

    吕跃东; 王勇; 张文革; 谢程程; 宫立晶; 王雪

    2011-01-01

    [目的]为寻找对水稻稻瘟病的有防治作用的有益微生物及其代谢产物,研究放线菌BOS-013菌株发酵液对水稻稻瘟病菌的抑制作用.[方法]以水稻稻瘟病菌作为目标指示菌,采用杯碟法和滤纸片法测定BOS-13菌株发酵液及其不同溶剂提取物的抑菌活性.[结果]研究结果表明,含菌量为4×10cfu/ml的BOS-13菌株发酵液对水稻稻瘟病菌的抑制率为92.O%±0.5%;该发酵液经高温、高压灭活后对水稻稻瘟病菌仍有抑制作用,抑制率为60.0%±0.5%.发酵液经非极性CAD-5型大孔吸附树脂吸附、60%乙醇溶液洗脱后,其抑菌活性很高,抑菌圈直径达33.0 mm.[结论]BOS-13菌株发酵液水稻稻瘟病菌有显著的抑制作用;该研究结果为进一步明确BOS-13菌株发酵液时水稻稻瘟病菌的抑制作用机理及其实际应用奠定了基础.%[ Objective ] To search for the beneficial microorganisms and their metabolic products with control effect against rice blast, the paper studied the inhibition effect of the fermentation broth of actinomycetes BOS-013 strain against the pathogen of rice blast (Pyricularia oryzae). [ Method] With the pathogen of rice blast as the target indicator fungus, the inhibition effect of the fermentation broth of BOS-013 strain and its extracts from different solvents against the pathogen were determined using cylinder plate method and filter paper method. [ Resuit] The results showed that the inhibition rate of the fermentation broth of BOS-013 strain with fungus amount of 4 × l08 cfu/ml against the pathogen of rice blast was 92.0% ± 0.5%; the fermentation broth still had inhibition effect against the pathogen of rice blast after inactivation under high temperature and high pressure, and the inhibition rate was 60.0% ± 0.5%. After absorbed by non-polar CAD-45 type macroporous adsorption resin and eluted by 60% ethanol, the antifungal activity of the fermentation broth was still high, and the diameter of

  7. 30 CFR 57.6803 - Blasting lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting lines. 57.6803 Section 57.6803 Mineral... and Underground § 57.6803 Blasting lines. Permanent blasting lines shall be properly supported. All blasting lines shall be insulated and kept in good repair. General Requirements—Surface and Underground...

  8. 30 CFR 56.6312 - Secondary blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Secondary blasting. 56.6312 Section 56.6312... Secondary blasting. Secondary blasts fired at the same time in the same work area shall be initiated from one source. Electric Blasting...

  9. 30 CFR 56.6803 - Blasting lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting lines. 56.6803 Section 56.6803 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Blasting lines. Permanent blasting lines shall be properly supported. All blasting lines shall be...

  10. 29 CFR 1926.912 - Underwater blasting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Underwater blasting. 1926.912 Section 1926.912 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.912 Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired...

  11. 30 CFR 75.1323 - Blasting circuits.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting circuits. 75.1323 Section 75.1323... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...

  12. Performance of blasting caps

    Science.gov (United States)

    Bement, Laurence J. (Inventor); Schimmel, Morry L. (Inventor); Perry, Ronnie B. (Inventor)

    1993-01-01

    Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.

  13. 30 CFR 57.22601 - Blasting from the surface (I-A mines).

    Science.gov (United States)

    2010-07-01

    ... shall be approved by MSHA under the applicable requirements of 30 CFR parts 18 through 36. Effective... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting from the surface (I-A mines). 57.22601... Standards for Methane in Metal and Nonmetal Mines Explosives § 57.22601 Blasting from the surface (I-A...

  14. Boundary-layer theory for blast waves

    Science.gov (United States)

    Kim, K. B.; Berger, S. A.; Kamel, M. M.; Korobeinikov, V. P.; Oppenheim, A. K.

    1975-01-01

    It is profitable to consider the blast wave as a flow field consisting of two regions: the outer, which retains the properties of the inviscid solution, and the inner, which is governed by flow equations including terms expressing the effects of heat transfer and, concomitantly, viscosity. The latter region thus plays the role of a boundary layer. Reported here is an analytical method developed for the study of such layers, based on the matched asymptotic expansion technique combined with patched solutions.

  15. Numerical simulation of muzzle blast

    NARCIS (Netherlands)

    Tyler-Street, M.

    2014-01-01

    Structural design methods for naval ships include environmental, operational and military load cases. One of the operational loads acting on a typical naval vessel is the muzzle blast from a gun. Simulating the muzzle blast load acting on a ship structure with CFD and ALE methods leads to large nume

  16. DAMAGE EFFECTS TO ROCK AND ENGINEERING APPLICATIONS OF DIRECTIONAL PRESSURE RELIEF VIBRATION ISOLATION BLASTING%定向卸压隔振爆破对岩石的损伤破坏效应及其工程应用

    Institute of Scientific and Technical Information of China (English)

    张志呈; 廖涛; 陈晓玲

    2015-01-01

    To reduce the destruction damage of conventional blasting on reserved rock,a new blasting method, namely,directional pressure relief vibration isolation blasting,is proposed and its technical principles are introduced. The test results of hopkinson bar,ultra-dynamic,dynamic caustics,dynamic photoelasticity,level one light gas gun and other tests results show that:this method would make explosion pressure reduced by 30% to 60% on the isolation material side;blasting vibration peak decreased by 32% to 67%;detonation wave would be blocked 46.95% and sound velocity reduced 13.48% on the isolation material side. The primary shear stress of the free surface side is 3.5 times of that on the isolation material side;stress intensity factors are 1 to 2.12 times of that on isolation material side. Engineering practices show that it brings a large number of energy together in free surface,geting a good blasting effect,meanwhile it can reduce the cost of the open pit slope excavation and overexcavation in drifting.%为降低常规爆破对保留岩体的破坏损伤,提出了定向卸压隔振爆破方法,并介绍了其技术原理。霍普金森杆、超动态、动焦散、动光弹和一级轻气炮等试验结果表明:采用定向卸压隔振爆破隔振材料一侧爆炸初始压力降低了30%~60%,爆破振动峰值下降了32%~67%;作用于隔振材料一侧爆轰波能量被阻隔46.95%,隔振材料一侧保留岩石的声速降低13.48%;临空面一侧的主剪应力是隔振材料一侧的3.5倍,应力强度因子是隔振材料一侧的1~2.12倍。实践表明,临空面方向汇集了大量能量,获得了好的爆破效果,同时可以减少露天边坡的开挖费用和平巷掘进超欠挖量。

  17. Structural safety criteria for blasting vibration based on wavelet packet energy spectra

    Institute of Scientific and Technical Information of China (English)

    Zhong Guosheng; Li Jiang; Zhao Kui

    2011-01-01

    Given multi-resolution decomposition of wavelet packet transforms, wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals. Our deduction reflects the total effect of all three key elements (intensity, frequency and duration of vibration) of blasting vibration.We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration. Frequency band response coefficients for controlled structures by blasting vibration have been obtained. We established multi-factor blasting vibration safety criteria, referred to as response energy criteria. These criteria reflect the total effect of intensity,frequency and duration of vibration and the inherent characteristics (natural frequency and damping ratio) of dynamic responses from controlled structures themselves. Feasibility and reliability of the criteria are validated by an example.

  18. A preliminary study on the effect of agro-meteorological factors on molecular mechanism of rice blast occurrence%农业气象因素影响稻瘟病发生分子机制初探

    Institute of Scientific and Technical Information of China (English)

    刘天华; 白姣姣; 吕东平

    2016-01-01

    Rice is an important food crop in China. Rice blast, a disease caused by ascomycetes (Magnaporthe oryzae), is one of most limiting factors of rice production in the country, which results in huge economic losses to the rice production each year. With the completion of whole genome sequencing of rice and M. oryzae, the interaction mechanism of rice and M. oryzae has become much clearer. Resistance to rice blast fungus can effectively prevent the invasion of pathogenic bacteria through the natural immune system of rice. Also pathogens can cause diseases in susceptible rice varieties by inhibiting innate immune system of rice. Outbreaks of rice blast and popular occur under three necessary conditions — susceptible rice variety, pathogenic bacteria and pathogenic meteorological factors. Thus the meteorological factors for the outbreak and epidemics of rice blast play an important role. Based on research achievements in recent years, this paper summarized the interaction mechanism of rice and M. oryzae from the pointing of pathogenic process of M. oryzae and rice resistance, discussed the effects of temperature, illumination, humidity and other meteorological factors on the pathogenesis of M. oryzae and disease resistance of rice. The paper further explored the molecular mechanism of invasion of rice blast epidemic caused by the factors, expecting to find the best ways for preventing and controlling rice blast. Finally, the paper provided theoretical evidences in support of proper prevention and treatment methods of rice blast.%水稻是我国重要的粮食作物,由子囊菌(Magnaporthe oryzae)所引起的稻瘟病是水稻生产活动中的重要限制因子之一,每年给水稻生产造成巨大的经济损失。随着水稻及稻瘟菌全基因组测序工作的完成,水稻和稻瘟菌间的互作机制已日渐明朗。水稻对稻瘟菌的抗性主要来自于自身体内天然免疫机制对病原菌入侵的有效阻止,同时病原菌能够通过

  19. An RES-Based Model for Risk Assessment and Prediction of Backbreak in Bench Blasting

    Science.gov (United States)

    Faramarzi, F.; Ebrahimi Farsangi, M. A.; Mansouri, H.

    2013-07-01

    Most blasting operations are associated with various forms of energy loss, emerging as environmental side effects of rock blasting, such as flyrock, vibration, airblast, and backbreak. Backbreak is an adverse phenomenon in rock blasting operations, which imposes risk and increases operation expenses because of safety reduction due to the instability of walls, poor fragmentation, and uneven burden in subsequent blasts. In this paper, based on the basic concepts of a rock engineering systems (RES) approach, a new model for the prediction of backbreak and the risk associated with a blast is presented. The newly suggested model involves 16 effective parameters on backbreak due to blasting, while retaining simplicity as well. The data for 30 blasts, carried out at Sungun copper mine, western Iran, were used to predict backbreak and the level of risk corresponding to each blast by the RES-based model. The results obtained were compared with the backbreak measured for each blast, which showed that the level of risk achieved is in consistence with the backbreak measured. The maximum level of risk [vulnerability index (VI) = 60] was associated with blast No. 2, for which the corresponding average backbreak was the highest achieved (9.25 m). Also, for blasts with levels of risk under 40, the minimum average backbreaks (<4 m) were observed. Furthermore, to evaluate the model performance for backbreak prediction, the coefficient of correlation ( R 2) and root mean square error (RMSE) of the model were calculated ( R 2 = 0.8; RMSE = 1.07), indicating the good performance of the model.

  20. Thermodynamic modeling of lead blast furnace

    Institute of Scientific and Technical Information of China (English)

    TAN Peng-fu

    2005-01-01

    A thermodynamic model was developed to predict the distribution behavior of Cu,Fe,S,O,Pb,Zn,As,and the heat balance in a lead blast furnace.The modeling results are validated by the plant data of a lead smelter in Kazakhstan.The model can be used to predict any set of controllable process parameters such as feed composition,smelting temperature,degree of oxygen enrichment and volume of oxygen-enriched air.The effects of the blast air,industrial oxygen,and coke charge on the distribution of Cu,Fe,S,O,Pb,Zn,As,the heat balance,and the lead loss in slag,were presented and discussed.

  1. Aquaporin 9, a promising predictor for the cytocidal effects of arsenic trioxide in acute promyelocytic leukemia cell lines and primary blasts.

    Science.gov (United States)

    Iriyama, Noriyoshi; Yuan, Bo; Yoshino, Yuta; Hatta, Yoshihiro; Horikoshi, Akira; Aizawa, Shin; Takeuchi, Jin; Toyoda, Hiroo

    2013-06-01

    A close correlation between the cytocidal effects of arsenic trioxide (ATO) and aquaporin-9 (AQP9) expression levels has been proposed, yet detailed studies are still needed to confirm this association. Thus, in the present study, the correlation between the expression levels of AQP9 and sensitivity to ATO was investigated using two acute promyelocytic leukemia (APL) cell lines, NB4 and HT93A, as well as primary APL cells from newly diagnosed and relapsed APL patients. A substantially higher sensitivity to ATO-mediated induction of apoptosis was observed in the NB4 cells when compared to that in the HT93A cells. In addition, markedly higher expression levels of AQP9, as assessed using flow cytometry, along with more intracellular arsenic accumulation, were observed in the NB4 cells. More importantly, similar to APL cell lines, the trend of expression levels of AQP9 correlated closely with the differential sensitivity to ATO-mediated induction of apoptosis in primary APL cells. In contrast, no correlation was observed between ATO sensitivity associated with AQP9 expression levels and the expression profiles of cell surface markers as well as chromosomal alterations. These results provide direct evidence that the expression levels of AQP9, rather than other biomarkers such as cell surface markers and chromosomal alterations, correlate closely with the sensitivity to ATO in both APL cell lines and primary blasts. These findings suggest that the AQP9 expression status of APL patients is a predictive marker for the successful outcome of ATO treatment, since AQP9 plays a pivotal role in various arsenite-mediated biological effects on normal and cancer cells. Moreover, flow cytometry may be a new convenient and valuable tool for analyzing the AQP9 status of APL patients compared to current methods such as western blotting.

  2. Predicting the Impact of Rock Blasting on Building Structures at Awunakrom in the Ahanta West District of Ghana

    Directory of Open Access Journals (Sweden)

    K.J. Bansah

    2014-07-01

    Full Text Available Blasting is an important process after drilling is completed in hard rock mining. It involves placing explosives in drill holes and detonating them to cause explosion. The energy released during this process fragments the rocks into sizes for desired end use. The detonation of these explosives may produce undesirable effects such as ground vibration which is capable of causing damage to building structures. It is therefore, necessary to conduct blast impact studies to determine potential impact of blast induced ground vibration prior to mining and establish remediation techniques. Blast impact study was conducted at Awunakrom in the Ahanta West District of Ghana. Building structures within the study area were mapped and characterized. A blast impact prediction model was also generated. Blast induced vibrations that may propagate from the Father Brown pit of Golden Star Wassa Limited using various instantaneous charges were determined. It was found that bench blasting at the Father Brown pit has a potential of causing damage to building structures within the Awunakrom community if the maximum instantaneous charge adopted at the southernmost periphery of the pit exceeds 30 kg. It was therefore, recommended that all bench blast conducted at the southern periphery of the Father Brown pit should adopt a maximum instantaneous charge of 30 kg to avert any potential blast damage. However, variable instantaneous charges of more than 30 kg can be adopted as the blast location moves towards the northern periphery.

  3. High-low-blasting technology and its application in methane dynamic disaster prevention

    Institute of Scientific and Technical Information of China (English)

    LI Xian-zhong; LIN Bai-quan; YANG Wei; NI Guan-hua; LI Quan-gui

    2011-01-01

    The gas cooperative control model combined local pressure-relief with regional pressure-relief was established,based on the theory of multi-parameters cooperative.For the status of high gas contents,high in-situ stress and low-permeability of Ji-15 seam of No.12 coal mine in Pingmei Group.The law of detonation wave propagation and ground-stress change distribution were simulated by means of the finite element analysis software.The technology of high-low-blasting,composed of high blasting(deep crossing hole controlled hydraulic blasting) and low blasting (special roadway deep hole controlled blasting) were developed.The research shows that around control hole produce maximum tension fracture failure,and result in directional and controlled blasting,when the distance between control hole and blasting hole is 1.2 m.The theory makes blasting force and hydraulic force advantage superimpose,which raises the effect of pressure relief and permeability enhancements compared with general blasting.High blasting influence radius and low blasting influence radius superimposed with each other,that prevents methane dynamic disaster.The result of type approval test shows that the technology can increase gas permeability as high as 22.7~36.2 ratio,decrease gas pressure from 2.85 MPa to 0.30 MPa,increase drilling influence radius to about 9 m.The technology realizes regional overall permeability improvement,that provides a new technical measure for methane dynamic disaster prevention.

  4. Abrasive Blasting Unit (ABU) - 16270

    International Nuclear Information System (INIS)

    NUKEM Technologies was contracted to supply a dry, automated drum belt (tumbling) Abrasive Blasting Unit (ABU) to the Joint Research Centre of the European Commission in Ispra, Italy. The ABU was installed in the centralised radioactive waste management area of the JRC-Ispra site in Italy. The unit is to be employed for the decontamination to clearance levels of slightly contaminated metal components and, where practical, concrete or heavy concrete (density ∼3200 kg/m3) blocks arising from the dismantling of nuclear facilities. The presentation is based on the successful construction and installation of the ABU at the JRC Ispra site. Among the several possibilities of adapting conventional abrasive units to nuclear applications, an automatic tumbling machine was preferred, due to the larger output and (mainly) for the ease of operation, with minimum direct handling of contaminated material by operators, thus satisfying the ALARA principle. Consideration was also given to Belgoprocess' successful experience with a predecessor, similar unit. After adequate size reduction batches of up to about 800 kg of material to be decontaminated are automatically introduced into the blasting chamber. Pieces between 100 mm and 800 mm long, between 100 mm and 500 mm wide and between 5 mm and 300 mm high can be effectively treated in the unit, the maximum weight of a single piece being limited to 100 kg. Short lengths of pipe may be included; the final dimensions of pipe to be decontaminated will be established during the nuclear commissioning tests. Other components with hard-to-reach surfaces may also be included. The content of the chamber is tumbled by two bladed drums, while sharp steel grit is sprayed onto the contaminated components, thus removing the surface layer including any contamination. From experience, 30 minutes of treatment is sufficient to remove contamination to levels below expected clearance levels for most materials. The decontaminated components are removed

  5. A Modified Surface on Titanium Deposited by a Blasting Process

    Directory of Open Access Journals (Sweden)

    Caroline O’Sullivan

    2011-09-01

    Full Text Available Hydroxyapatite (HA coating of hard tissue implants is widely employed for its biocompatible and osteoconductive properties as well as its improved mechanical properties. Plasma technology is the principal deposition process for coating HA on bioactive metals for this application. However, thermal decomposition of HA can occur during the plasma deposition process, resulting in coating variability in terms of purity, uniformity and crystallinity, which can lead to implant failure caused by aseptic loosening. In this study, CoBlastTM, a novel blasting process has been used to successfully modify a titanium (V substrate with a HA treatment using a dopant/abrasive regime. The impact of a series of apatitic abrasives under the trade name MCD, was investigated to determine the effect of abrasive particle size on the surface properties of both microblast (abrasive only and CoBlast (HA/abrasive treatments. The resultant HA treated substrates were compared to substrates treated with abrasive only (microblasted and an untreated Ti. The HA powder, apatitic abrasives and the treated substrates were characterized for chemical composition, coating coverage, crystallinity and topography including surface roughness. The results show that the surface roughness of the HA blasted modification was affected by the particle size of the apatitic abrasives used. The CoBlast process did not alter the chemistry of the crystalline HA during deposition. Cell proliferation on the HA surface was also assessed, which demonstrated enhanced osteo-viability compared to the microblast and blank Ti. This study demonstrates the ability of the CoBlast process to deposit HA coatings with a range of surface properties onto Ti substrates. The ability of the CoBlast technology to offer diversity in modifying surface topography offers exciting new prospects in tailoring the properties of medical devices for applications ranging from dental to orthopedic settings.

  6. OPTIMAL PARAMETERS OF BLASTING IN TUNNELS USING PATRONED AND PUMPED EXPLOSIVES WITH ELECTRIC AND NON-ELECTRIC INITIATION

    OpenAIRE

    2003-01-01

    The parameters of drilling and blasting procedures during excavation of Grič and mala Kapela Tunnels are presented in this work. The tunnels are being constructed according to NATM (New Austrian Tunneling Method) in two parallel tubes. By Comparison of blasting with patroned and pumped explosives and electric and non-electric mode of initiation, optimal technological parameters have been defined concerning duration of blasting working cycle, progress, tunnel category and seismic effects of bl...

  7. An Experimental Study on the Fabrication of Glass-based Acceleration Sensor Body Using Micro Powder Blasting Method

    OpenAIRE

    Park, Dong-Sam; Yun, Dae-Jin; Cho, Myeong-Woo; Shin, Bong-Cheol

    2007-01-01

    This study investigated the feasibility of the micro powder blasting technique for the micro fabrication of sensor structures using the Pyrex glass to replace the existing silicon-based acceleration sensor fabrication processes. As the preliminary experiments, the effects of the blasting pressure, the mass flow rate of abrasive and the number of nozzle scanning times on erosion depth of the Pyrex and the soda lime glasses were examined. From the experimental results, optimal blasting conditio...

  8. 高程放大效应对露天采场爆破震动衰减的影响研究%Research on the influence of elevation amplification effect on open-pit blasting vibration attenuation

    Institute of Scientific and Technical Information of China (English)

    胡光球; 璩世杰; 梁新民

    2015-01-01

    露天采场边坡对爆源不高于坡脚处的爆破震动存在放大作用。通过对露天采场高程放大效应机理分析,认为萨道夫斯基公式难以准确描述采场内爆破震动衰减规律;通过引入高程因素对萨道夫斯基公式进行修正,运用最小二乘法原理进行多元线性回归分析,建立震动衰减模型。对司家营铁矿Ⅱ采场中深孔爆破进行现场监测,验证了高程放大效应的存在。回归计算结果表明,修正的萨道夫斯基公式更具科学性。%The open pit slope can amplify blasting vibration whose explosion source is not higher than the toe of slope.Based on the analysis of the mechanism of elevation amplification effect in open pit,the paper considers that Sa-dove formula has difficulty in accurately describing blasting vibration attenuation law in stope.So a modified Sadove formula with the introduction of the elevation factors and a multiple linear regression analysis performed by the princi-ple of least square method combine to establish the attenuation model.The existence of elevation amplification effect is verified by monitoring medium-long hole blasting in No.Ⅱ stope of Sijiaying Iron Mine.The regression calculation re-sults prove the modified Sadove formula to be more scientific.

  9. Spalling of concrete walls under blast load

    International Nuclear Information System (INIS)

    A common effect of the detonation of explosives in close proximity of concrete shield walls is the spalling (scabbing) of the back face of the wall. For explosions close-in to the wall, where the reflected blast wave pressures are sufficiently high, multiple spall layers are formed. Successive spall layers are of increasing thickness, at the same time the spall velocities decrease. For a given wall configuration and peak blast wave pressure the spall thickness scales directly with the cube root of the charge weight. The spall velocities on the other hand, which are proportional to the impulse trapped in the spall layer, vary only slightly with charge weight due to minor differences of shock attenuation in the wall. For a given charge weight, the spall thickness increases with stand-off distance from the wall and the spall velocity decreases. For fixed charge stand-off distance the spall thicknesses decrease as the charge weight is increased, at the same time spall velocities increase. This is caused by the steeper pressure decay associated with higher blast wave pressures. Fixing the charge parameters, spall thicknesses increase slightly as the wall thickness is increased. The opposite holds for the spalling velocities. As the angle of incidence for the blast wave increases the spall thicknesses increase also. Again the corresponding spall velocities decrease. Assuming elastic concrete behavior, no spalling will occur for angles of shock wave incidence greater than 450. A phase reversal of the reflection coefficient occurs at this point, thus the longitudinal wave reflected at the free surface becomes a compression wave

  10. A Study on the Vibration Frequency of Blasting Excavation in Highly Stressed Rock Masses

    Science.gov (United States)

    Yang, Jianhua; Lu, Wenbo; Jiang, Qinghui; Yao, Chi; Jiang, Shuihua; Tian, Lin

    2016-07-01

    During blasting excavation in deep-buried tunnels and mines characterized by high in situ stress, the rock vibration is attributed not only to blast loading, but also to dynamic unloading caused by transient release of the in situ stress on excavation faces in the process of rock fragmentation by blasting. Understanding the vibration frequency characteristics under these two excitation sources is of important signification to determine appropriate vibration threshold limits for structure damage in deep-buried opening excavations. With a theoretical model developed for a deep-buried circular tunnel excavation by the millisecond delay blasting sequence, frequency characteristics and their influence factors are investigated and discussed for the vibrations induced by the blast loading, the dynamic unloading and the combined effects, respectively. The results show that the rising time of blast loading, the duration of dynamic unloading and the dimension of excavation boundaries are the main factors that affect the vibration frequency of blasting excavation in highly stressed rock masses. It is found that, the blast loading with a much shorter rising time accentuates higher vibration frequency than the dynamic unloading with a long duration, and it causes the blast loading vibration to be more readily attenuated as the propagation distance increases. Thus, the unloading vibration may become the main vibration component at far distances where its low-frequency vibration may exceed the vibration limits. The vibration induced by the combined effects has two distinctly dominant frequency bands corresponding to the two vibration excitation sources. The frequency analyses of the vibration records from two underground projects excavated by blasting are presented to demonstrate this finding. The findings of this study also clearly reveal that, reducing the dimension of excavation boundaries is one of the most effective means to prevent the vibrational damage to structures as it

  11. Comparative Study of Response of Structures Subjected To Blast and Earthquake Loading

    Directory of Open Access Journals (Sweden)

    Aditya C. Bhatt

    2016-05-01

    Full Text Available The increase in the number of terrorist attacks especially in the last few years has shown that the effect of blast load on building is a serious challenge that should be taken in to consideration for designing of structures. This type of loading damages the structures, externally as well as internally. Hence the blast load should be considered with same importance as earthquake load. The present study includes the comparative performance of G+3 storey building subjected to blast and earthquake loading using ETABS. For four storey building using different input parameters like charge explosive, stand-off distance and layout of building the blast pressure are conducted and linear time history analysis is carried out. Comparative study for blast and earthquake loading is carried out for different parameters like maximum storey displacement, storey drift and quantity of materials. Safe charge explosive and safe stand-off distance are obtained for the RCC structure with the sections of structural elements same as per the requirement for earthquake resistance. Displacement is higher for the blast loading as compared to earthquake loading and very high for the storey at which blast load is applied. Quantity of concrete is 40 percentages higher for blast resistant building than the earthquake resistant building.

  12. Blast/fire interaction scaling

    International Nuclear Information System (INIS)

    Hypotheses are formulated of the process of interaction between an airblast and fires supported by liquid fuels and wood cribs. A map of blast weakness versus fire strength is conceived on which the regime of fire extinction by the blast can be delineated from the regime where the fire will sustain the blast. The fire strength is described for liquid fuels primarily by the heat of combustion; and for wood, it is mainly described by the preburn time. The concept is substantiated by the SRI shocktube data

  13. Proceedings of the ninth annual symposium on explosives and blasting research

    International Nuclear Information System (INIS)

    This edition of the proceedings of the Annual Symposium on Explosives and Blasting Research is ninth in a series published by the International Society of Explosive Engineers and made available as part of a collection known as the Blasters Library. As a focal point of the explosives industry, the Society serves as a repository of information, promotes the exchange of ideas between nations, conducts forum identifying issues of concern to the industry and fosters interaction between the explosives engineering community and other segments of society. The papers in this edition cover a wide variety of topics on blasting technology and research: performance optimization of explosives, mechanics of explosions, blast design for a variety of applications, blast monitoring techniques, blast effects and their mitigation, and detonator design. Twenty-seven papers were selected for inclusion in the Energy Data Base

  14. Working toward exposure thresholds for blast-induced traumatic brain injury: thoracic and acceleration mechanisms

    CERN Document Server

    Courtney, Michael; 10.1016/j.neuroimage.2010.05.025

    2011-01-01

    Research in blast-induced lung injury resulted in exposure thresholds that are useful in understanding and protecting humans from such injury. Because traumatic brain injury (TBI) due to blast exposure has become a prominent medical and military problem, similar thresholds should be identified that can put available research results in context and guide future research toward protecting warfighters as well as diagnosis and treatment. At least three mechanical mechanisms by which the blast wave may result in brain injury have been proposed - a thoracic mechanism, head acceleration and direct cranial transmission. These mechanisms need not be mutually exclusive. In this study, likely regions of interest for the first two mechanisms based on blast characteristics (positive pulse duration and peak effective overpressure) are developed using available data from blast experiments and related studies, including behind-armor blunt trauma and ballistic pressure wave studies. These related studies are appropriate to in...

  15. PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE

    Directory of Open Access Journals (Sweden)

    CHANG-SU SHIM

    2013-06-01

    Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.

  16. Application of coupled analysis methods for prediction of blast-induced dominant vibration frequency

    Science.gov (United States)

    Li, Haibo; Li, Xiaofeng; Li, Jianchun; Xia, Xiang; Wang, Xiaowei

    2016-03-01

    Blast-induced dominant vibration frequency (DVF) involves a complex, nonlinear and small sample system considering rock properties, blasting parameters and topography. In this study, a combination of grey relational analysis and dimensional analysis procedures for prediction of dominant vibration frequency are presented. Six factors are selected from extensive effect factor sequences based on grey relational analysis, and then a novel blast-induced dominant vibration frequency prediction is obtained by dimensional analysis. In addition, the prediction is simplified by sensitivity analysis with 195 experimental blast records. Validation is carried out for the proposed formula based on the site test database of the firstperiod blasting excavation in the Guangdong Lufeng Nuclear Power Plant (GLNPP). The results show the proposed approach has a higher fitting degree and smaller mean error when compared with traditional predictions.

  17. A study on impulsive sound attenuation for a high-pressure blast flow field

    International Nuclear Information System (INIS)

    The present work addresses a numerical study on impulsive sound attenuation for a complex high-pressure blast flow field; these characteristics are generated by a supersonic propellant gas flow through a shock tube into an ambient environment. A numerical solver for analyzing the high pressure blast flow field is developed in this study. From numerical simulations, wave dynamic processes (which include a first precursor shock wave, a second main propellant shock wave, and interactions in the muzzle blasts) are simulated and discussed. The pressure variation of the blast flow field is analyzed to evaluate the effect of a silencer. A live firing test is also performed to evaluate four different silencers. The results of this study will be helpful in understanding blast wave and in designing silencers

  18. Correcting BLAST e-values for low-complexity segments.

    Science.gov (United States)

    Sharon, Itai; Birkland, Aaron; Chang, Kuan; El-Yaniv, Ran; Yona, Golan

    2005-09-01

    The statistical estimates of BLAST and PSI-BLAST are of extreme importance to determine the biological relevance of sequence matches. While being very effective in evaluating most matches, these estimates usually overestimate the significance of matches in the presence of low complexity segments. In this paper, we present a model, based on divergence measures and statistics of the alignment structure, that corrects BLAST e-values for low complexity sequences without filtering or excluding them and generates scores that are more effective in distinguishing true similarities from chance similarities. We evaluate our method and compare it to other known methods using the Gene Ontology (GO) knowledge resource as a benchmark. Various performance measures, including ROC analysis, indicate that the new model improves upon the state of the art. The program is available at biozon.org/ftp/ and www.cs.technion.ac.il/ approximately itaish/lowcomp/.

  19. The importance of systemic response in the pathobiology of blast-induced neurotrauma

    Directory of Open Access Journals (Sweden)

    Ibolja eCernak

    2010-12-01

    Full Text Available Due to complex injurious environment where multiple blast effects interact with the body, parallel blast-induced neurotrauma is a unique clinical entity induced by systemic, local, and cerebral responses. Activation of autonomous nervous system; sudden pressure-increase in vital organs such as lungs and liver; and activation of neuroendocrine-immune system are among the most important mechanisms that contribute significantly to molecular changes and cascading injury mechanisms in the brain. It has been hypothesized that vagally mediated cerebral effects play a vital role in the early response to blast: this assumption has been supported by experiments where bilateral vagotomy mitigated bradycardia, hypotension, and apnea, and also prevented excessive metabolic alterations in the brain of animals exposed to blast. Clinical experience suggests specific blast-body-nervous system interactions such as 1 direct interaction with the head either through direct passage of the blast wave through the skull or by causing acceleration and/or rotation of the head; and 2 via hydraulic interaction, when the blast overpressure compresses the abdomen and chest, and transfers its kinetic energy to the body’s fluid phase, initiating oscillating waves that traverse the body and reach the brain. Accumulating evidence suggests that inflammation plays important role in the pathogenesis of long-term neurological deficits due to blast. These include memory decline, motor function and balance impairments, and behavioral alterations, among others. Experiments using rigid body- or head protection in animals subjected to blast showed that head protection failed to prevent inflammation in the brain or reduce neurological deficits, whereas body protection was successful in alleviating the blast-induced functional and morphological impairments in the brain.

  20. Centrifugal shot blast system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997.

  1. Centrifugal shot blast system

    International Nuclear Information System (INIS)

    This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997

  2. Source model for blasting vibration

    Institute of Scientific and Technical Information of China (English)

    DING; Hua(丁桦); ZHENG; Zhemin(郑哲敏)

    2002-01-01

    By analyzing and comparing the experimental data, the point source moment theory and the cavity theory, it is concluded that the vibrating signals away from the blasting explosive come mainly from the natural vibrations of the geological structures near the broken blasting area. The source impulses are not spread mainly by the inelastic properties (such as through media damping, as believed to be the case by many researchers) of the medium in the propagation pass, but by this structure. Then an equivalent source model for the blasting vibrations of a fragmenting blasting is proposed, which shows the important role of the impulse of the source's time function under certain conditions. For the purpose of numerical simulation, the model is realized in FEM, The finite element results are in good agreement with the experimental data.

  3. Explosive Blast Neuropathology and Seizures

    Directory of Open Access Journals (Sweden)

    S. Krisztian eKovacs

    2014-04-01

    Full Text Available Traumatic brain injury (TBI due to explosive blast exposure is a leading combat casualty. It is also implicated as a key contributor to war related mental health diseases. A clinically important consequence of all types of TBI is a high risk for development of seizures and epilepsy. Seizures have been reported in patients who have suffered blast injuries in the Global War on Terror but the exact prevalence is unknown. The occurrence of seizures supports the contention that explosive blast leads to both cellular and structural brain pathology. Unfortunately, the exact mechanism by which explosions cause brain injury is unclear, which complicates development of meaningful therapies and mitigation strategies. To help improve understanding, detailed neuropathological analysis is needed. For this, histopathological techniques are extremely valuable and indispensable. In the following we will review the pathological results, including those from immunohistochemical and special staining approaches, from recent preclinical explosive blast studies.

  4. Design of Blast Resistant Structure

    Directory of Open Access Journals (Sweden)

    C. K. Gautam

    1997-04-01

    Full Text Available A shock blast resistant structure designed, developed and experimentally evaluated by the authors is described. We structure, capable of with standing dynamic loading (12 psi and a static pressure of 1.5 m earth cover due to blast or any other explosion, also gives protection against radiation, chemical and thermal hazards. Some results and details of analysis and experimentation are presented.

  5. Stability of Relativistic Blast Waves

    OpenAIRE

    OGURA, Jun; Kojima, Yasufumi

    2000-01-01

    A spherical blast wave with relativistic velocity can be described by a similarity solution, that is used for theoretical models of gamma-ray bursts. We consider the linear stability of such a relativistic blast wave propagating into a medium with density gradient. The perturbation can also be expressed by a self-similar form. We show that the shock front is unstable in general, and we evaluate the growth rate.

  6. Blast waves with cosmic rays

    Science.gov (United States)

    Arbutina, B.

    2015-04-01

    Blast waves appear in many astrophysical phenomena, such as supernovae. In this paper we discuss blast waves with cosmic rays, i.e., with a component with a power-law number density distribution function N( p) ∝ p -Γ that may be particulary important in describing the evolution of supernova remnants. We confirm some previous findings that a significant amount of cosmic ray energy is deposited towards the center of a remnant.

  7. Numerical analysis of prestressed reinforced concrete beam subjected to blast loading

    International Nuclear Information System (INIS)

    Highlights: • Numerical study of prestressed RC beam against blast loadings by using LS-DYNA. • Numerical model is calibrated with testing results available. • The prestress is pre-applied on the RC beam in an analytical approach. • Parametric studies on prestress, concrete compressive strength and blast load. • Blast resistance performance of prestressed beam is identified. - Abstract: Prestressing technique has been widely used in civilian and military constructions. The prestressed reinforced concrete (RC) structural components such as beams and columns usually outperform the non-prestressed RC components because prestressing not only increases the structural stiffness and load carrying capacity, but also has higher crack resistance than non-prestressed component. As a result, it usually leads to light structures. The investigation of non-prestressed RC components subjected to blast loadings has been reported in the literature. However, the study on the blast-resistant capacity of prestressed RC components is very limited. In this study, the dynamic response of a simply-supported prestressed RC beam with rectangular section under blast loadings is numerically investigated by using finite element codes LS-DYNA. The prestress is pre-applied on the RC beam in an analytical approach. The reliability of the numerical model is calibrated with testing results available in the literature. With the calibrated model, numerical simulations on four groups of prestressed RC beams to blast loadings are carried out to investigate the influences of prestressing level and concreted compressive strength on beam blast loading resistance capacity. The structural responses such as mid-span maximum deflection, residual deflection, cracking, stress of rebars and shear stress of concrete near the supports are extracted from the numerical results. The effectiveness of prestressing on blast-resistant capacity of RC beam is demonstrated through comparing the results with the

  8. Analysis of blasting damage in adjacent mining excavations

    Directory of Open Access Journals (Sweden)

    Nick Yugo

    2015-06-01

    Full Text Available Following a small-scale wedge failure at Yukon Zinc's Wolverine Mine in Yukon, Canada, a vibration monitoring program was added to the existing rockbolt pull testing regime. The failure in the 1150 drift occurred after numerous successive blasts in an adjacent tunnel had loosened friction bolts passing through an unmapped fault. Analysis of blasting vibration revealed that support integrity is not compromised unless there is a geological structure to act as a failure plane. The peak particle velocity (PPV rarely exceeded 250 mm/s with a frequency larger than 50 Hz. As expected, blasting more competent rock resulted in higher PPVs. In such cases, reducing the round length from 3.5 m to 2.0 m was an effective means of limiting potential rock mass and support damage.

  9. Blast impact behaviour of concrete with different fibre reinforcement

    Science.gov (United States)

    Drdlová, Martina; Čechmánek, René; Řídký, Radek

    2015-09-01

    The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer) of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concrete prism specimens have been subjected to the determination of mechanical parameters (compressive and flexural strength at quasi-static load). The blast tests were conducted on the slab specimens prepared from selected mixtures. The material characteristics and explosion test data have been used for numerical investigation, which defined the optimal wall composition and dimensions of the concrete element which should resist the explosion defined by type, size, weight and placement of the blast. In the next step the test elements resistance was verified by real explosion test.

  10. REINFORCED CONCRETE SILO DEMOLITION BY BLASTING

    OpenAIRE

    Josip Krsnik; Zvonimir Ester; Marin Petrov

    1993-01-01

    This paper represents the demolition of reinforced concrete silo by blasting. The loadbearing structure was blasted so that the weight of the silo itself done most of the felling (the paper is published in Croatian).

  11. Prospects for studying how high-intensity compression waves cause damage in human blast injuries

    Science.gov (United States)

    Brown, Katherine; Bo, Chiara; Ramaswamy, Arul; Masouros, Spiros; Newell, Nicolas; Hill, Adam; Clasper, Jon; Bull, Anthony; Proud, William

    2011-06-01

    Blast injuries arising from improvised explosive devices are often complex leading to long-term disability in survivors. There is an urgent need to mitigate against the effects of blast that lead to these injuries, and to also improve post-traumatic therapeutic treatments related to problems associated with damage and healing processes and infections. We have initiated multidisciplinary studies to develop experimental facilities and strategies for analyzing the effects blast waves upon the human body, from cellular through to skeletal functions. This work is supported by the Atomic Weapons Establishment and the Defence Science and Technology Laboratory, UK.

  12. Numerical Simulation of Fluid Flow in Blast Furnace Hearth

    Institute of Scientific and Technical Information of China (English)

    ZHAO Min-ge; SUN Tian-liang; CHENG Su-sen; GAO Zheng-kai

    2005-01-01

    The liquid flow in blast furnace hearth can result in the erosion of hearth. To prolong the campaign life of blast furnace, the effects of coke bed structure, coke porosity and deepness of taphole on liquid flow in hearth were studied by κ-ε model under different conditions. The results show that with the decrease of coke porosity, the peripheral flow is enhanced. Moreover, the existence of narrow coke free zone and the deepness reduction of taphole can increase the flowability on the bottom of hearth.

  13. Wavelet basis construction method based on separation blast vibration signal

    Institute of Scientific and Technical Information of China (English)

    凌同华; 张胜; 陈倩倩; 李洁

    2015-01-01

    As wavelet basis in wavelet analysis is neither arbitrary nor unique, the same signal dealing with different wavelet bases will generate different results. Therefore, how to construct a wavelet basis suitable for the characteristics of the analyzed signal and solve its algorithm and realization is a fundamental problem which perplexed many researchers. To solve these problems, in accordance with the basic features of the measured millisecond blast vibration signal, a new wavelet basis construction method based on the separation blast vibration signal is proposed, and the feasibility of this method is verified by comparing the practical effect of the newly constructed wavelet with other known wavelets in signal processing.

  14. Asymmetric propagation of airblast from bench blasting

    OpenAIRE

    Segarra Catasús, Pablo; Sanchidrián Blanco, José Angel; López Sánchez, Lina María; Domingo, Jesús Felix

    2011-01-01

    This paper investigates the propagation of airblast from quarry blasting. Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and polar coordinates of the point of interest (distance to the blast and azimuth with respect to the free face of the blast). The model is in the form of the product of a classical scaled distance attenuation law times a directional correction factor. The...

  15. Service robot for hull-blasting

    OpenAIRE

    Ortiz Zaragoza, Francisco José; Iborra García, Andrés José; Álvarez Torres, María Bárbara; Marín García, Fulgencio; Fernández Meroño, José María

    2001-01-01

    Present grit blasting technology for hull cleaning is very pollutant, environmentally unaffordable, and it is progressively forbidden in the most environmental countries (mainly north of Europe). At the time being, the above methodology has been partially substituted by ultra highpressure water blasting, however they do not show as good performance as the grit blasting systems. This paper describes a service robot for hull blasting. The technology we developed consists of the cleanin...

  16. Towards a fast-running method for blast-wave mitigation by a prismatic blast wall

    Science.gov (United States)

    Éveillard, Sébastien; Lardjane, Nicolas; Vinçont, Jean-Yves; Sochet, Isabelle

    A procedure aimed at developing a fast-running method for blast-wave effects characterization behind a protection barrier is presented. Small-scale experiments of a hemispherical gaseous charge (stoichiometric propane-oxygen mixture) without and with a prismatic protective barrier are used to validate the use of an in-house CFD code for gaseous detonation. From numerical experiments, pressure loss of a blast wave at a corner is quantified. These fits, in conjunction with TM5-1300 reflection charts, are used to estimate the maximum overpressure around a protective barrier through geometrical and empirical laws. The results show good agreement with numerical and experimental data from the ANR-BARPPRO research project.

  17. Effect of Neighborhood Tunnel Blasting Construction on Existing Tunnel%超小净距隧道爆破施工对既有隧道的影响研究

    Institute of Scientific and Technical Information of China (English)

    林金耐

    2013-01-01

    Based on Beihuan tunnel of Lanzhou pivotal project up-traversing Hongshanding tunnel, numerical simulation is performed to obtain effects of neighborhood tunnel blasting construction on existing tunnel. The results show that the existing tunnel has been less affected with excavation of bench cut method, and blasting construction, vibration velocity and stress of secondary lining have fulfilled security in existing tunnel, so the newly-built tunnel could across over the existing tunnel safely.%以兰州枢纽工程北环隧道上穿既有红山顶铁路隧道为研究对象,通过数值模拟,研究了超小净距隧道爆破施工对既有隧道的影响.结果表明:新建隧道台阶法爆破施工,下方既有铁路隧道受到的影响较小,既有隧道二次衬砌振动速度及衬砌应力能够满足安全性要求,新建隧道可安全通过.

  18. 30 CFR 57.6312 - Secondary blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Secondary blasting. 57.6312 Section 57.6312... Transportation-Surface and Underground § 57.6312 Secondary blasting. Secondary blasts fired at the same time in the same work area shall be initiated from one source. Electric Blasting—Surface and Underground...

  19. 30 CFR 72.610 - Abrasive blasting.

    Science.gov (United States)

    2010-07-01

    ... respirators approved for abrasive blasting by NIOSH under 42 CFR part 84, or the operation shall be performed... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abrasive blasting. 72.610 Section 72.610... HEALTH STANDARDS FOR COAL MINES Miscellaneous § 72.610 Abrasive blasting. (a) Surface and...

  20. Toxicology of blast overpressure.

    Science.gov (United States)

    Elsayed, N M

    1997-07-25

    Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that are occurring worldwide with greater frequency. Exposure to incident BOP waves can cause auditory and non-auditory damage. The primary targets for BOP damage are the hollow organs, ear, lung and gastrointestinal tract. In addition, solid organs such as heart, spleen and brain can also be injured upon exposure. However, the lung is more sensitive to damage and its injury can lead to death. The pathophysiological responses, and mortality have been extensively studied, but little attention, was given to the biochemical manifestations, and molecular mechanism(s) of injury. The injury from BOP has been, generally, attributed to its external physical impact on the body causing internal mechanical damage. However, a new hypothesis has been proposed based on experiments conducted in the Department of Respiratory Research, Walter Reed Army Institute of Research, and later in the Department of Occupational Health, University of Pittsburgh. This hypothesis suggests that subtle biochemical changes namely, free radical-mediated oxidative stress occur and contribute to BOP-induced injury. Understanding the etiology of these changes may shed new light on the molecular mechanism(s) of injury, and can potentially offer new strategies for treatment. In this symposium. BOP research involving auditory, non-auditory, physiological, pathological, behavioral, and biochemical manifestations as well as predictive modeling and current treatment modalities of BOP-induced injury are discussed.

  1. Blast-Associated Shock Waves Result in Increased Brain Vascular Leakage and Elevated ROS Levels in a Rat Model of Traumatic Brain Injury.

    Directory of Open Access Journals (Sweden)

    Shushi Kabu

    Full Text Available Blast-associated shock wave-induced traumatic brain injury (bTBI remains a persistent risk for armed forces worldwide, yet its detailed pathophysiology remains to be fully investigated. In this study, we have designed and characterized a laboratory-scale shock tube to develop a rodent model of bTBI. Our blast tube, driven by a mixture of oxygen and acetylene, effectively generates blast overpressures of 20-130 psi, with pressure-time profiles similar to those of free-field blast waves. We tested our shock tube for brain injury response to various blast wave conditions in rats. The results show that blast waves cause diffuse vascular brain damage, as determined using a sensitive optical imaging method based on the fluorescence signal of Evans Blue dye extravasation developed in our laboratory. Vascular leakage increased with increasing blast overpressures and mapping of the brain slices for optical signal intensity indicated nonhomogeneous damage to the cerebral vasculature. We confirmed vascular leakage due to disruption in the blood-brain barrier (BBB integrity following blast exposure. Reactive oxygen species (ROS levels in the brain also increased with increasing blast pressures and with time post-blast wave exposure. Immunohistochemical analysis of the brain sections analyzed at different time points post blast exposure demonstrated astrocytosis and cell apoptosis, confirming sustained neuronal injury response. The main advantages of our shock-tube design are minimal jet effect and no requirement for specialized equipment or facilities, and effectively generate blast-associated shock waves that are relevant to battle-field conditions. Overall data suggest that increased oxidative stress and BBB disruption could be the crucial factors in the propagation and spread of neuronal degeneration following blast injury. Further studies are required to determine the interplay between increased ROS activity and BBB disruption to develop effective

  2. Blast-Associated Shock Waves Result in Increased Brain Vascular Leakage and Elevated ROS Levels in a Rat Model of Traumatic Brain Injury.

    Science.gov (United States)

    Kabu, Shushi; Jaffer, Hayder; Petro, Marianne; Dudzinski, Dave; Stewart, Desiree; Courtney, Amy; Courtney, Michael; Labhasetwar, Vinod

    2015-01-01

    Blast-associated shock wave-induced traumatic brain injury (bTBI) remains a persistent risk for armed forces worldwide, yet its detailed pathophysiology remains to be fully investigated. In this study, we have designed and characterized a laboratory-scale shock tube to develop a rodent model of bTBI. Our blast tube, driven by a mixture of oxygen and acetylene, effectively generates blast overpressures of 20-130 psi, with pressure-time profiles similar to those of free-field blast waves. We tested our shock tube for brain injury response to various blast wave conditions in rats. The results show that blast waves cause diffuse vascular brain damage, as determined using a sensitive optical imaging method based on the fluorescence signal of Evans Blue dye extravasation developed in our laboratory. Vascular leakage increased with increasing blast overpressures and mapping of the brain slices for optical signal intensity indicated nonhomogeneous damage to the cerebral vasculature. We confirmed vascular leakage due to disruption in the blood-brain barrier (BBB) integrity following blast exposure. Reactive oxygen species (ROS) levels in the brain also increased with increasing blast pressures and with time post-blast wave exposure. Immunohistochemical analysis of the brain sections analyzed at different time points post blast exposure demonstrated astrocytosis and cell apoptosis, confirming sustained neuronal injury response. The main advantages of our shock-tube design are minimal jet effect and no requirement for specialized equipment or facilities, and effectively generate blast-associated shock waves that are relevant to battle-field conditions. Overall data suggest that increased oxidative stress and BBB disruption could be the crucial factors in the propagation and spread of neuronal degeneration following blast injury. Further studies are required to determine the interplay between increased ROS activity and BBB disruption to develop effective therapeutic strategies

  3. Destabilization analysis of overlapping underground chambers induced by blasting vibration with catastrophe theory

    Institute of Scientific and Technical Information of China (English)

    YAN Chang-bin; XU Guo-yuan; ZUO Yu-jun

    2006-01-01

    According to the main characters of overlapping underground chambers, the roof (floor) of two adjacent underground chambers is simplified to the mechanical model that is the beam with build-in ends. And vibration load due to blasting is simplified to harmonic wave. The catastrophic model of double cusp for underground chambers destabilization induced by blasting vibration has been established under the circumstances of considering deadweight of the beam, and the condition of destabilization has been worked out. The critical safety thickness of the roof (floor) of underground chambers has been confirmed according to the destabilization condition. The influence of amplitude and frequency of blasting vibration load on the critical safety thickness has been analyzed, and the quantitative relation between velocity, frequency of blasting vibration and critical safety thickness has been determined. Research results show that the destabilization of underground chambers is not only dependent on the amplitude and frequency of blasting vibration load, but also related to deadweight load and intrinsic attribute. It is accordant to testing results and some related latest research results of blasting seismic effect. With increasing amplitude, the critical safety thickness of underground chambers decreases gradually. And the possibility of underground chambers destabilization increases. When the frequency of blasting vibration is equal to or very close to the frequency of beam, resonance effect will take place in the system. Then the critical safety thickness will turn to zero, underground chambers will be damaged severely, and its loading capacity will lose on the whole.

  4. Determination of blast-induced ground vibration equations for rocks using mechanical and geological properties

    Institute of Scientific and Technical Information of China (English)

    Ranjan Kumar; Deepankar Choudhury; Kapilesh Bhargava

    2016-01-01

    In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity (PPV) and peak particle displacement (PPD) are commonly used for estimation of blast loads in design. However, these relation-ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation (RQD), geological strength index (GSI), and uniaxial compressive strength (UCS). The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases.

  5. A Thoracic Mechanism of Mild Traumatic Brain Injury Due to Blast Pressure Waves

    CERN Document Server

    Courtney, Amy; 10.1016/j.mehy.2008.08.015

    2008-01-01

    The mechanisms by which blast pressure waves cause mild to moderate traumatic brain injury (mTBI) are an open question. Possibilities include acceleration of the head, direct passage of the blast wave via the cranium, and propagation of the blast wave to the brain via a thoracic mechanism. The hypothesis that the blast pressure wave reaches the brain via a thoracic mechanism is considered in light of ballistic and blast pressure wave research. Ballistic pressure waves, caused by penetrating ballistic projectiles or ballistic impacts to body armor, can only reach the brain via an internal mechanism and have been shown to cause cerebral effects. Similar effects have been documented when a blast pressure wave has been applied to the whole body or focused on the thorax in animal models. While vagotomy reduces apnea and bradycardia due to ballistic or blast pressure waves, it does not eliminate neural damage in the brain, suggesting that the pressure wave directly affects the brain cells via a thoracic mechanism. ...

  6. Analogue experimental study on centrifugal-air blast granulation for molten slag

    International Nuclear Information System (INIS)

    Blast furnace slag is a by-product in iron and steel production process which has a high yield with extremely high discharge temperature. Aiming at energy and water saving as well as emission reduction, dry granulation technique appears to be a good application for the treatment of blast furnace slag. In this study, a granulation technique combining a high-speed rotating cup with air blast is proposed. The performance of this design was investigated by adopting a mixture of rosin and paraffin wax as the analogue of blast furnace slag. The effects of rotating speed of the atomizer, liquid flow rate and blast air flow rate on particle size, particle mass distribution and fiber mass fraction were studied. The effect of the function of air blast on the granulation performance was particularly discussed. The results showed that at a higher rotating speed and a smaller liquid flow rate, smaller particles can be easily obtained, yet the fiber mass fraction also increases. However, the increasing blast air leads to the increase of particle size and fiber mass fraction. For the operating conditions tested in this study, over 60% of total mass of particles fall within the size range of 0.5–1 mm, which means that the present system has a good performance in centrifugal granulation

  7. Understanding yield reduction in rice due to leaf blast.

    NARCIS (Netherlands)

    Bastiaans, L.

    1993-01-01

    The study described in this thesis focuses on a quantitative understanding of the effect of leaf blast on growth and production of a rice crop, based on insight in the physiological processes underlying damage. For this purpose, experimental research was conducted at two levels of integration: plant

  8. Domain enhanced lookup time accelerated BLAST

    Directory of Open Access Journals (Sweden)

    Boratyn Grzegorz M

    2012-04-01

    Full Text Available Abstract Background BLAST is a commonly-used software package for comparing a query sequence to a database of known sequences; in this study, we focus on protein sequences. Position-specific-iterated BLAST (PSI-BLAST iteratively searches a protein sequence database, using the matches in round i to construct a position-specific score matrix (PSSM for searching the database in round i + 1. Biegert and Söding developed Context-sensitive BLAST (CS-BLAST, which combines information from searching the sequence database with information derived from a library of short protein profiles to achieve better homology detection than PSI-BLAST, which builds its PSSMs from scratch. Results We describe a new method, called domain enhanced lookup time accelerated BLAST (DELTA-BLAST, which searches a database of pre-constructed PSSMs before searching a protein-sequence database, to yield better homology detection. For its PSSMs, DELTA-BLAST employs a subset of NCBI’s Conserved Domain Database (CDD. On a test set derived from ASTRAL, with one round of searching, DELTA-BLAST achieves a ROC5000 of 0.270 vs. 0.116 for CS-BLAST. The performance advantage diminishes in iterated searches, but DELTA-BLAST continues to achieve better ROC scores than CS-BLAST. Conclusions DELTA-BLAST is a useful program for the detection of remote protein homologs. It is available under the “Protein BLAST” link at http://blast.ncbi.nlm.nih.gov. Reviewers This article was reviewed by Arcady Mushegian, Nick V. Grishin, and Frank Eisenhaber.

  9. 30 CFR 75.1326 - Examination after blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Examination after blasting. 75.1326 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1326 Examination after blasting. (a) After blasting, the blasting area shall not be entered until it is clear of...

  10. 30 CFR 77.1300 - Explosives and blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and blasting. 77.1300 Section 77... Explosives and Blasting § 77.1300 Explosives and blasting. (a) No explosives, blasting agent, detonator, or any other related blasting device or material shall be stored, transported, carried, handled,...

  11. Appraise a combination of fungicides against blast and sheath blight diseases of paddy (Oryza sativa L.)

    OpenAIRE

    Prasanna Kumar M K; Veerabhadraswamy A L

    2014-01-01

    In present study various fungicides were screened against blast (leaf and neck) and sheath blight disease of rice. Among them, Conika 50% WP (Kasugamycin 5% + Copper Oxychloride 45% WP), Dhanucop Team (Tricyclazole 75% WP) and RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG) were found effective against blast diseases. While, the seed treatment fungicide Isotianil SC 200 and its combination with Trifloxystrobin 500 SC were found least effective against leaf and neck bla...

  12. 冲击爆炸作用对核电站安全壳毁伤效应研究的进展%State of Arts of Impact and Blast Effects on the NPPC

    Institute of Scientific and Technical Information of China (English)

    吴昊; 方秦; 龚自明; 赵建魁

    2012-01-01

    For the disastrous results of the released reactive fuel after the damage to the nuclear power plants (NPP), the NPP containment (NPPC) is one of the most potential targets in both military strikes and terroristic activities. In this paper, the state of arts of key scientific problems, which are related to the impact and blast effects of the projectiles and airplanes striking on the NPPC are concluded. It is pointed out that the main focuses in the research of the protective performance of NPPC are: Firstly, the damage effect of double layered reinforced concrete shields and steel liner composite target under the high-speed penetration (perforation) and blast effects of projectile; Secondly, the fine numerical simulations of the dynamic responses of NPPC under the impact of large commercial airplanes, with the consideration of the double-layered structure, concrete model, mass and rigidity distribution of the airplane, impact velocity and location, loading area and etc. ; Thirdly, the damage mechanism of reinforced concrete under coupling effects of impact & blast and fire.%核电站破坏后放射性燃料泄露带来的灾难性后果,使得核电站特别是核反应堆成为军事打击和恐怖袭击的重要目标之一.本文分析总结了核反应堆安全壳因弹体和飞机的冲(撞)击爆炸导致受损所涉及的关键科学问题的国内外研究进展,指出核安全壳体防护效能的研究重点主要在于:弹体“侵彻(贯穿)+爆炸”作用对双层钢筋混凝土和内衬钢板复合核安全壳结构的毁伤效应;综合考虑安全壳体结构、混凝土材料模型、飞机质量与刚度分布、撞击速度和位置、加载面积等因素影响的大型商用飞机撞击核安全壳全过程的精细化数值模拟;冲击爆炸与火荷载多灾场耦合作用下钢筋混凝土核安全壳的损伤破坏机理.

  13. Blast shock wave mitigation using the hydraulic energy redirection and release technology.

    Science.gov (United States)

    Chen, Yun; Huang, Wei; Constantini, Shlomi

    2012-01-01

    A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel.

  14. Blast shock wave mitigation using the hydraulic energy redirection and release technology.

    Directory of Open Access Journals (Sweden)

    Yun Chen

    Full Text Available A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel.

  15. Blast shock wave mitigation using the hydraulic energy redirection and release technology.

    Science.gov (United States)

    Chen, Yun; Huang, Wei; Constantini, Shlomi

    2012-01-01

    A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel. PMID:22745740

  16. A coupling of empirical explosive blast loads to ALE air domains in LS-DYNA (registered)

    International Nuclear Information System (INIS)

    A coupling method recently implemented in LS-DYNA (registered) allows empirical explosive blast loads to be applied to air domains treated with the multi-material arbitrary Lagrangian-Eulerian (ALE) formulation. Previously, when simulating structures subjected to blast loads, two methods of analysis were available: a purely Lagrangian approach or one involving the ALE and Lagrangian formulations coupled with a fluid-structure interaction (FSI) algorithm. In the former, air blast pressure is computed with empirical equations and directly applied to Lagrangian elements of the structure. In the latter approach, the explosive as well as the air are explicitly modeled and the blast wave propagating through the ALE air domain impinges on the Lagrangian structure through FSI. Since the purely Lagrangian approach avoids modeling the air between the explosive and structure, a significant computational cost savings can be realized - especially so when large standoff distances are considered. The shortcoming of the empirical blast equations is their inability to account for focusing or shadowing of the blast waves due to their interaction with structures which may intervene between the explosive and primary structure of interest. The new method presented here obviates modeling the explosive and air leading up the structure. Instead, only the air immediately surrounding the Lagrangian structures need be modeled with ALE, while effects of the far-field blast are applied to the outer face of that ALE air domain with the empirical blast equations; thus, focusing and shadowing effects can be accommodated yet computational costs are kept to a minimum. Comparison of the efficiency and accuracy of this new method with other approaches shows that the ability of LS-DYNA (registered) to model a variety of new blast scenarios has been greatly extended.

  17. Effect of Rheological Behavior of Particle-Water Suspensions on Properties of Gunned Refractory for Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; MENG Qing-min; LONG Shi-gang; SUN Jia-lin; HONG Yan-ruo

    2006-01-01

    Study on rheological properties of gunned refractory is an effective way to optimize the quality of repaired layer and gunning operation. The fluidity of refractory was quantitatively evaluated as well as the rheological behavior of refractory particle-water suspensions. The relationship between the fluidity of refractory particle-water suspension and that of gunned refractory, and the relationship between the fluidity and adhesion ability of gunned refractory were studied. The experiments were carried out with a special rheometer and gunning machine. The results show that there is strong influence of some parameters on the rheological behavior of gunned refractory and gunning process. Interactions between particles and water that lead to the formation of gelatinous structures in this suspension are discussed.

  18. A blast of gas in the latest Paleocene: simulating first-order effects of massive dissociation of oceanic methane hydrate

    Science.gov (United States)

    Dickens, G. R.; Castillo, M. M.; Walker, J. C.

    1997-01-01

    Carbonate and organic matter deposited during the latest Paleocene thermal maximum is characterized by a remarkable -2.5% excursion in delta 13C that occurred over approximately 10(4) yr and returned to near initial values in an exponential pattern over approximately 2 x 10(5) yr. It has been hypothesized that this excursion signifies transfer of 1.4 to 2.8 x 10(18) g of CH4 from oceanic hydrates to the combined ocean-atmosphere inorganic carbon reservoir. A scenario with 1.12 x 10(18) g of CH4 is numerically simulated here within the framework of the present-day global carbon cycle to test the plausibility of the hypothesis. We find that (1) the delta 13C of the deep ocean, shallow ocean, and atmosphere decreases by -2.3% over 10(4) yr and returns to initial values in an exponential pattern over approximately 2 x 10(5) yr; (2) the depth of the lysocline shoals by up to 400 m over 10(4) yr, and this rise is most pronounced in one ocean region; and (3) global surface temperature increases by approximately 2 degrees C over 10(4) yr and returns to initial values over approximately 2 x 10(6) yr. The first effect is quantitatively consistent with the geologic record; the latter two effects are qualitatively consistent with observations. Thus, significant CH4 release from oceanic hydrates is a plausible explanation for observed carbon cycle perturbations during the thermal maximum. This conclusion is of broad interest because the flux of CH4 invoked during the maximum is of similar magnitude to that released to the atmosphere from present-day anthropogenic CH4 sources.

  19. Innovative design tool for the optimization of blast-enhanced facade systems

    Directory of Open Access Journals (Sweden)

    Guido Lori

    2015-06-01

    Full Text Available In current blast enhancement design strategies, to resist the effects of an accidental explosion, a facade system is commonly designed to behave in-elastically and undergo large deformations. The large deformation of the facade system leads to high blast energy dissipation, subsequently reducing the blast energy transferred to the main structure. In addition to the blast resistance of the facade system, human injuries due to glass fragmentation within the vicinity of the facade system should also be minimized in order to meet the required safety levels. Overall building safety can be optimized by balancing blast energy dissipation and glass fragmentation. Recently, Permasteelisa Group has developed an innovative design tool to optimize blast-enhanced facades using an equivalent MDOF approach. A novel fragmentation tool has been proposed to assist this design procedure. This paper presents various critical parameters considered in blast-enhanced facade analysis, the experimental validation of these parameters and their influence in the design optimization process.  

  20. Prediction of environmental impacts of quarry blasting operation using fuzzy logic.

    Science.gov (United States)

    Fişne, Abdullah; Kuzu, Cengiz; Hüdaverdi, Türker

    2011-03-01

    Blast-induced ground vibration is one of the most important environmental impacts of blasting operations because it may cause severe damage to structures and plants in nearby environment. Estimation of ground vibration levels induced by blasting has vital importance for restricting the environmental effects of blasting operations. Several predictor equations have been proposed by various researchers to predict ground vibration prior to blasting, but these are site specific and not generally applicable beyond the specific conditions. In this study, an attempt has been made to predict the peak particle velocity (PPV) with the help of fuzzy logic approach using parameters of distance from blast face to vibration monitoring point and charge weight per delay. The PPV and charge weight per delay were recorded for 33 blast events at various distances and used for the validation of the proposed fuzzy model. The results of the fuzzy model were also compared with the values obtained from classical regression analysis. The root mean square error estimated for fuzzy-based model was 5.31, whereas it was 11.32 for classical regression-based model. Finally, the relationship between the measured and predicted values of PPV showed that the correlation coefficient for fuzzy model (0.96) is higher than that for regression model (0.82).

  1. Viscoelastic Materials Study for the Mitigation of Blast-Related Brain Injury

    Science.gov (United States)

    Bartyczak, Susan; Mock, Willis, Jr.

    2011-06-01

    Recent preliminary research into the causes of blast-related brain injury indicates that exposure to blast pressures, such as from IED detonation or multiple firings of a weapon, causes damage to brain tissue resulting in Traumatic Brain Injury (TBI) and Post Traumatic Stress Disorder (PTSD). Current combat helmets are not sufficient to protect the warfighter from this danger and the effects are debilitating, costly, and long-lasting. Commercially available viscoelastic materials, designed to dampen vibration caused by shock waves, might be useful as helmet liners to dampen blast waves. The objective of this research is to develop an experimental technique to test these commercially available materials when subject to blast waves and evaluate their blast mitigating behavior. A 40-mm-bore gas gun is being used as a shock tube to generate blast waves (ranging from 1 to 500 psi) in a test fixture at the gun muzzle. A fast opening valve is used to release nitrogen gas from the breech to impact instrumented targets. The targets consist of aluminum/ viscoelastic polymer/ aluminum materials. Blast attenuation is determined through the measurement of pressure and accelerometer data in front of and behind the target. The experimental technique, calibration and checkout procedures, and results will be presented.

  2. Blast neurotrauma impairs working memory and disrupts prefrontal myo-inositol levels in rats.

    Science.gov (United States)

    Sajja, Venkata Siva Sai Sujith; Perrine, Shane A; Ghoddoussi, Farhad; Hall, Christina S; Galloway, Matthew P; VandeVord, Pamela J

    2014-03-01

    Working memory, which is dependent on higher-order executive function in the prefrontal cortex, is often disrupted in patients exposed to blast overpressure. In this study, we evaluated working memory and medial prefrontal neurochemical status in a rat model of blast neurotrauma. Adult male Sprague-Dawley rats were anesthetized with 3% isoflurane and exposed to calibrated blast overpressure (17 psi, 117 kPa) while sham animals received only anesthesia. Early neurochemical effects in the prefrontal cortex included a significant decrease in betaine (trimethylglycine) and an increase in GABA at 24 h, and significant increases in glycerophosphorylcholine, phosphorylethanolamine, as well as glutamate/creatine and lactate/creatine ratios at 48 h. Seven days after blast, only myo-inositol levels were altered showing a 15% increase. Compared to controls, short-term memory in the novel object recognition task was significantly impaired in animals exposed to blast overpressure. Working memory in control animals was negatively correlated with myo-inositol levels (r=-.759, p<0.05), an association that was absent in blast exposed animals. Increased myo-inositol may represent tardive glial scarring in the prefrontal cortex, a notion supported by GFAP changes in this region after blast overexposure as well as clinical reports of increased myo-inositol in disorders of memory. PMID:24534010

  3. Mild blast events alter anxiety, memory, and neural activity patterns in the anterior cingulate cortex.

    Directory of Open Access Journals (Sweden)

    Kun Xie

    Full Text Available There is a general interest in understanding of whether and how exposure to emotionally traumatizing events can alter memory function and anxiety behaviors. Here we have developed a novel laboratory-version of mild blast exposure comprised of high decibel bomb explosion sound coupled with strong air blast to mice. This model allows us to isolate the effects of emotionally fearful components from those of traumatic brain injury or bodily injury typical associated with bomb blasts. We demonstrate that this mild blast exposure is capable of impairing object recognition memory, increasing anxiety in elevated O-maze test, and resulting contextual generalization. Our in vivo neural ensemble recording reveal that such mild blast exposures produced diverse firing changes in the anterior cingulate cortex, a region processing emotional memory and inhibitory control. Moreover, we show that these real-time neural ensemble patterns underwent post-event reverberations, indicating rapid consolidation of those fearful experiences. Identification of blast-induced neural activity changes in the frontal brain may allow us to better understand how mild blast experiences result in abnormal changes in memory functions and excessive fear generalization related to post-traumatic stress disorder.

  4. Surface mine blasting near pressurized transmission pipelines. Report of investigations/1994

    Energy Technology Data Exchange (ETDEWEB)

    Siskind, D.E.; Stagg, M.S.; Wiegand, J.E.; Schulz, D.L.

    1994-12-31

    The mining industry and regulatory agencies have requested guidance on blasting near buried transmission pipelines and safe vibration levels. The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Company and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN for testing to failure. Four 17- to 51-cm diameter welded steel pipes and one 20-cm PVC water pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the pipeline field. In contrast to previous studies of small-scale close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blast-holes. Analyses found low responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120-250 mm/s produced worst case strains of about 25 pct of those resulting from pipeline operations and calculated stresses of only about 10-18 pct of the ultimate tensile strength.

  5. Time-frequency characteristics of blasting vibration signals measured in milliseconds

    Institute of Scientific and Technical Information of China (English)

    Zhao Mingsheng; Zhang Jianhua; Yi Changping

    2011-01-01

    In order to study the time-frequency characteristics of blasting vibration signals,measured in milliseconds,we carried out site blasting vibration tests at an open pit of the Jinduicheng Mine.Based on recorded field data and applying a combination of RSPWVD and wavelet,.we analyzed the time-frequency characteristics of recorded field data.summarized the time-frequency characteristics of blasting vibration signals in different frequency bands and present detailed information of blasting vibration signals in milliseconds of high time-frequency resolutions.Because RSPWVD can be seen as of definite physical significance to signal energy distribution in time and frequency domains,we studied the energy distribution of blasting vibration signals for various milliseconds intervals from a perspective of energy distribution.The results indicate that the effect of milliseconds intervals on time-frequency characteristics of blasting vibration signals is significant:the length of delay time directly affects the energy distribution of blasting vibration signals as well as the duration of energy in frequency bands.

  6. Experimental studies on intake headloss of a blasted lake tap

    International Nuclear Information System (INIS)

    In existing reservoirs, construction of an intake is sometimes achieved by so-called lake tapping, a submerged tunnel piercing by blasting out the rock plug at the intake. The blasting process involves phases of rock, water, air and gas released from the explosive charge; the resulting entrance profile often differs from design assumptions. The intake headloss is a factor of concern for power generation. For a vertical intake formed by lake tapping, experiments have been carried out in a 1:30 physical model to examine the effect of entrance shapes on intake headlosses. The purpose is that, if there is potential to reduce the headlosses, the originally blasted intake shape would be modified. In the model, five alternative shapes are evaluated. The test results show that to enlarge the vertical shaft area is the most effective way to reduce the intake headloss; to further blast out a narrow channel upstream does not give much effect. Bearing in mind the risk of free-surface vortex at the intake, the influence of the intake modifications on vortex is also checked

  7. An analysis of the heap construction by long hole blasting for in-situ leaching of blasted ore

    International Nuclear Information System (INIS)

    The author establishes specific requirements for heap construction by blasting on the basis of the mechanism for in situ leaching of blasted ore, analyses the feasibility of heap construction by long hole blasting, selection of the blast plan and the relevant technological problems, and gives a case of heap construction by long hole blasting in Renhua uranium mine

  8. The effect of Er:YAG laser irradiation on hydroxyapatite-coated implants and fluoride-modified TiO2-blasted implant surfaces: a microstructural analysis.

    Science.gov (United States)

    Shin, Seung-Il; Lee, Eun-Kwon; Kim, Jeong-Hyun; Lee, Ji-Hun; Kim, Sun-Hee; Kwon, Young-Hyuk; Herr, Yeek; Chung, Jong-Hyuk

    2013-05-01

    The purpose of this study was to evaluate the microscopic changes and surface roughness on hydroxyapatite (HA)-coated implants following exposure to different powers and durations of Er:YAG laser irradiation in order to determine the proper pulse energy level and irradiation time. Ten HA-coated implants and ten fluoride-modified TiO2 implants were used. The implants were divided into a control (one implant) and test group (nine implants) for each implant type. Implants in the test groups were sub-divided into three groups (three implants per group) based on the applied laser pulse energy and irradiation time. The measurement of surface roughness was performed on all implants in the test groups using a white light interferometer before and after laser irradiation. R a values were recorded and compared in order to evaluate changes in surface roughness. For HA-coated implants, the R a values increased in all test groups after laser irradiation. However, mean R a values in the fluoride-modified TiO2-blasted implant test group were decreased after irradiation. There was no statistical difference. Scanning electron microscope analysis revealed surface alterations in both the HA-coated and fluoridated TiO2-blasted implants irradiated for 1.5 min at 100 mJ/pulse, 10 Hz. When the pulse energy and irradiation time increased, greater surface alterations, including surface flattening and microfractures, were observed. In conclusion, the results of the current study suggest that no changes could be observed in both HA-coated implants and fluoride-modified TiO2-blasted implants after irradiation at an intensity of 100 mJ/pulse, 10 Hz for 1 min performed to achieve surface detoxification.

  9. Improved BLAST for wireless communications

    Institute of Scientific and Technical Information of China (English)

    Li Yongzhao; Liao Guisheng; Wang Feng

    2006-01-01

    Bell layered space-time architecture (BLAST) is a multi-antenna communication structure with high spectrum efficiency, and it has found wide applications in LANs and WLANs. However, its performance is much poorer than those of other space-time coding approaches. In order to improve its performance, an improved BLAST based on RAKE receiving is investigated. The new system introduces orthogonal spreading sequences (OSS) into the transmitter while retains the basic structure of BLAST. The proposed receiver suppresses interferences from other antennas by the orthogonality contained in the received signals, and extracts information from each receiving antenna by using RAKE receiving principle to construct efficient statistic decision. Simulation results show that the improved system performs well over both frequency-flat and frequency-selective fading channels.

  10. Surface assessment and modification of concrete using abrasive blasting

    Science.gov (United States)

    Millman, Lauren R.

    Composite systems are applied to concrete substrates to strengthen and extend the service life. Successful restoration or rehabilitation requires surface preparation prior to the application of the overlay. Surface coatings, waterproofing systems, and other external surface applications also require surface preparation prior to application. Abrasive blast media is often used to clean and uniformly roughen the substrate. The appropriate surface roughness is necessary to facilitate a strong bond between the existing substrate and overlay. Thus, surface modification using abrasive blast media (sand and dry ice), their respective environmental effects, surface roughness characterization prior to and after blasting, and the adhesion between the substrate and overlay are the focus of this dissertation. This dissertation is comprised of an introduction, a literature review, and four chapters, the first of which addresses the environmental effects due to abrasive blasting using sand, water, and dry ice. The assessment considered four response variables: carbon dioxide (CO2) emissions, fuel and energy consumption, and project duration. The results indicated that for sand blasting and water jetting, the primary factor contributing to environmental detriment was CO22 emissions from vehicular traffic near the construction site. The second chapter is an analysis of the International Concrete Repair Institute's (ICRI) concrete surface profiles (CSPs) using 3-D optical profilometry. The primary objective was to evaluate the suitability of approximating the 3-D surface (areal) parameters with those extracted from 2-D (linear) profiles. Four profile directions were considered: two diagonals, and lines parallel and transverse to the longitudinal direction of the mold. For any CSP mold, the estimation of the 3-D surface roughness using a 2-D linear profile resulted in underestimation and overestimation errors exceeding 50%, demonstrating the inadequacy of 2-D linear profiles to

  11. Large scale germplasm screening for identification of novel rice blast resistance sources

    Directory of Open Access Journals (Sweden)

    Kumar eVasudevan

    2014-10-01

    Full Text Available Rice is a major cereal crop that contributes significantly to global food security. Biotic stresses, including the rice blast fungus, cause severe yield losses that significantly impair rice production worldwide. The rapid genetic evolution of the fungus often overcomes the resistance conferred by major genes after a few years of intensive agricultural use. Therefore, resistance breeding requires continuous efforts of enriching the reservoir of resistance genes/alleles to effectively tackle the disease. Seed banks represent a rich stock of genetic diversity, however, they are still under-explored for identifying novel genes and/or their functional alleles. We conducted a large-scale screen for new rice blast resistance sources in 4246 geographically diverse rice accessions originating from 13 major rice-growing countries. The accessions were selected from a total collection of over 120’000 accessions based on their annotated rice blast resistance information in the International Rice Genebank. A two-step resistance screening protocol was used involving natural infection in a rice uniform blast nursery and subsequent artificial infections with five single rice blast isolates. The nursery-resistant accessions showed varied disease responses when infected with single isolates, suggesting the presence of diverse resistance genes/alleles in this accession collection. In addition, 289 accessions showed broad-spectrum resistance against all five single rice blast isolates. The selected resistant accessions were genotyped for the presence of the Pi2 resistance gene, thereby identifying potential accessions for isolation of allelic variants of this blast resistance gene. Together, the accession collection with broad spectrum and isolate specific blast resistance represent the core material for isolation of previously unknown blast resistance genes and/or their allelic variants that can be deployed in rice breeding programs.

  12. Main agronomic traits and resistance to rice blast of space-induced mutant lines of Zhong-er-ruan-zhan

    International Nuclear Information System (INIS)

    The main agronomic traits and resistance to rice blast of 34 space-induced lines from an elite rice cultivar, Zhong-er-ruan-zhan were evaluated at their SP4. The resistance to blast of the mutant lines had been tested by two blast isolates previously. It was found that the mutant lines showed significant difference in plant height, effective panicles, panicle length and grains per panicle etc. from their parent. The range of variation in 1000-grain weight the largest, followed by the seed-setting rate, and that of effective panicles was the least among all the traits. Except for the line Z34, 33 mutant lines had broader resistance spectra than the wild-type based on the test with 38 different blast isolates, and all the 33 lines were also resistant to the panicle blast in the field. The result confirmed that selection for resistant to blast in lower generations was reliable. Taking account of agronomic traits and blast resistance, promising lines with resistance to blast and good agronomic characters could be selected from those mutant lines. Therefore, the elite rice germplasm with enhanced disease resistance can be produced. (authors)

  13. The Use of Rice Varietal Diversity for Rice Blast Control

    Institute of Scientific and Technical Information of China (English)

    ZHU You-yong; LI Zuo-shen; LU Bao-rong; CHEN Hai-ru; FAN Jing-hua; WANG Yun-yue; LI Yan; FAN Jin-xiang; YANG Shi-sheng; MA Guan-liang; CHEN Jian-bin

    2003-01-01

    Field experiments of mixed- (intercropping) and pure-planting (monoculture) of four rice vari-eties, representing improved hybrid varieties (Shanyou63 and Shanyou22) and high-quality traditional varie-ties (Huangkenuo and Zigu) from Yunnan Province, were conducted based on their differences in genetic back-ground and agro-economical characteristics. The results demonstrated that the mixed-planting of the hybridrice and high-quality traditional rice varieties had a significantly greater effect on controlling rice blast diseasethan the monocuiture of these varieties, particularly the traditional ones. It is evident for the highly suscepti-ble traditional varieties in mixed-planting to achieve disease control, with significant decreases in blast inci-dences and severity indexes. The blast control efficiency reached up to 83 - 98 % under such planting model.This suggests that an appropriate mixed-planting of rice varieties with diverse genetic background and agro-e-conomical characteristics is an effective approach for rice blast control. In addition, resistance of the tradi-tional rice varieties to lodging was considerably increased in the plots with mixed-planting, compared with theplots with monoculture. The average rate of grain-yield increase ranged from 6.5 to 9.7 % in the plots withmixed-planting.

  14. Experimental Investigation on the Basic Law of the Fracture Spatial Morphology for Water Pressure Blasting in a Drillhole Under True Triaxial Stress

    Science.gov (United States)

    Huang, Bingxiang; Li, Pengfeng

    2015-07-01

    zones: the blasting shock zone, the axial extension zone, and the orifice influence zone. The explosion shock zone is the range that is directly impacted by the explosive shock waves. The axial extension zone is the axial crack area with uniform width, which is formed when the blasting fracture in the edge of the explosion shock zone extends along the drillhole wall. The extension of the orifice influence zone is very large because the explosion stress waves reflect at the free face and generate tensile stress waves. In the water pressure blasting of the drillhole, the sealing section should be lengthened to allow the drillhole blasting cracks to extend sufficiently under the long-time effect of the blasting stress field of quasi-hydrostatic pressure.

  15. Study on ore stacking after blasting for stope leaching uranium

    International Nuclear Information System (INIS)

    Geology of ore deposits, technical conditions, mining methods and blasting parameters of in-situ leaching uranium after blasting for an outcrop ore body are introduced. Long hole blast is beneficial technique and can bring better economic benefits

  16. 30 CFR 57.20031 - Blasting underground in hazardous areas.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting underground in hazardous areas. 57... MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In underground areas where... removed to safe places before blasting....

  17. Blast Wave Characteristics and Equivalency

    OpenAIRE

    Sochet, Isabelle; Schneider, Helmut

    2010-01-01

    The characteristics of blast waves generated by detonation of gas clouds are studies theoretically and validated by both small-scale and large-scale experiments with ethylene-air mixtures of different equivalence ratio. The mixtures were confined in hemispherical or spherical balloons made from thin polyethylene foils of 0.75 m³ and 15 m³ in volume. The detonation of gas mixtures was initiated by a solid explosive. The characteristics of the blast wave in terms of overpressure, impulse and du...

  18. Blast waves in rotating media.

    Science.gov (United States)

    Rossner, L. F.

    1972-01-01

    The model investigated involves a cylindrically symmetric blast wave generated by an infinitely long line explosion in a cold and homogeneous gas rotating rigidly in its self-gravitational field. It is found that within the context of rotation in a gravitational field a blast wave will not adopt the one-zone form familiar from similarity solutions but, rather, a two-zone form. The inner compression zone arises as a response to the presence of the restoring force, which drives a rarefaction wave into the outer compression zone.

  19. Numerical study of rock blasting

    Science.gov (United States)

    Stefanov, Yu. P.; Bakeev, R. A.; Yudin, A. S.; Kuznetsova, N. S.

    2015-10-01

    The paper presents numerical simulation results on fracture of a concrete block due to dynamic explosive loads applied to the walls of a blast hole. Considered in the study is the influence of the pulse shape and rock properties on the pattern of irreversible deformation and cracking. It is found that a fractured zone bounded by a plastically deformed contour always arises around the explosion site. Comparison of elastoplastic deformation and fracture induced in the concrete block by explosion pulses of different durations and amplitudes shows that shorter pulses with higher amplitudes and steeper rise times provide a higher blasting efficiency.

  20. Optimization of Wet or Dry Micro-blasting on PVD Films by Various Al2O3 Grain Sizes for Improving the Coated Tools' Cutting Performance

    OpenAIRE

    K.-D. Bouzakis; Tsouknidas, A.; G. Skordaris; E. Bouzakis; Makrimallakis, S.; S. Gerardis; G. Katirtzoglou

    2011-01-01

    Micro-blasting on PVD coated tools is an effective technology for improving their cutting performance. Through micro-blasting, compressive stresses are induced into the film, thus increasing the coating hardness, but its brittleness too. Simultaneously, abrasion phenomena are activated, which may lead to roughness augmentation, film thickness decrease and substrate revelation. In this way, for a successful process conduct, it is pivotal to adapt, among others, the applied micro-blasting pres...

  1. Multiple Dissipative Devices for Blast-Resisting Cable-Supported Glazing Façades

    OpenAIRE

    Claudio Amadio; Chiara Bedon

    2013-01-01

    The paper analyzes the structural response of a high-level air blast loaded cable-supported façade. Since the glass panels and the cables present a typical brittle behavior and are subjected to elevated tensile stresses when a high-level explosion occurs, multiple dissipative devices are simultaneously introduced in the conventional glazing system to mitigate the maximum effects of the design blast wave. Dynamic analyses are performed using a sophisticated FE-model to describe accurately the ...

  2. Blast loading of masonry infills: testing and simulation

    OpenAIRE

    Pereira, João Miguel; Campos, José; Lourenço, Paulo B.

    2015-01-01

    This work intends to present a newly developed test setup for dynamic out-of-plane loading using underWater Blast Wave Generators (WBWG) as loading source. Underwater blasting operations have been, during the last decades, subject of research and development of maritime blasting operations (including torpedo studies), aquarium tests for the measurement of blasting energy of industrial explosives and confined underwater blast wave generators. WBWG allow a wide range for the produced blast impu...

  3. Combat Helmets and Blast Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Duncan Wallace

    2012-01-01

    Full Text Available Background: The conflicts in Iraq and Afghanistan and the prominence of traumatic brain injury (TBI, mostly from improvised explosive devices, have focused attention on the effectiveness of combat helmets. Purpose: This paper examines the importance of TBI, the role and history of the development of combat helmets, current helmet designs and effectiveness, helmet design methodology, helmet sensors, future research and recommendations. Method: A literature review was conducted using search terms – combat helmets, traumatic brain injury, concussion, Iraq, Afghanistan and helmet sensors, searching PubMed, MEDLINE, ProQuest and Google Scholar. Conclusions: At present, no existing helmet is able to fully protect against all threats faced on the battlefield. The prominence of traumatic brain injury from improvised explosive devices in the current conflicts in Iraq and Afghanistan has highlighted the limitations in knowledge about blast and how to provide protection from it. As a result, considerable research is currently occurring in how to protect the head from blast over-pressure. Helmet sensors may provide valuable data. Some new combat helmets may be able to protect against rifle rounds, but may result in injuries occurring behind body armour. Optimal combat helmet design requires a balance between the need for protection from trauma and the comfort and practicality of the helmet for the user to ensure the best outcomes.

  4. Comparative genomics and association mapping approaches for blast resistant genes in finger millet using SSRs.

    Directory of Open Access Journals (Sweden)

    B Kalyana Babu

    Full Text Available The major limiting factor for production and productivity of finger millet crop is blast disease caused by Magnaporthe grisea. Since, the genome sequence information available in finger millet crop is scarce, comparative genomics plays a very important role in identification of genes/QTLs linked to the blast resistance genes using SSR markers. In the present study, a total of 58 genic SSRs were developed for use in genetic analysis of a global collection of 190 finger millet genotypes. The 58 SSRs yielded ninety five scorable alleles and the polymorphism information content varied from 0.186 to 0.677 at an average of 0.385. The gene diversity was in the range of 0.208 to 0.726 with an average of 0.487. Association mapping for blast resistance was done using 104 SSR markers which identified four QTLs for finger blast and one QTL for neck blast resistance. The genomic marker RM262 and genic marker FMBLEST32 were linked to finger blast disease at a P value of 0.007 and explained phenotypic variance (R² of 10% and 8% respectively. The genomic marker UGEP81 was associated to finger blast at a P value of 0.009 and explained 7.5% of R². The QTLs for neck blast was associated with the genomic SSR marker UGEP18 at a P value of 0.01, which explained 11% of R². Three QTLs for blast resistance were found common by using both GLM and MLM approaches. The resistant alleles were found to be present mostly in the exotic genotypes. Among the genotypes of NW Himalayan region of India, VHC3997, VHC3996 and VHC3930 were found highly resistant, which may be effectively used as parents for developing blast resistant cultivars in the NW Himalayan region of India. The markers linked to the QTLs for blast resistance in the present study can be further used for cloning of the full length gene, fine mapping and their further use in the marker assisted breeding programmes for introgression of blast resistant alleles into locally adapted cultivars.

  5. A systematic exposition of the conservation equations for blast waves.

    Science.gov (United States)

    Oppenheim, A. K.; Lundstrom, E. A.; Kuhl, A. L.; Kamel, M. M.

    1971-01-01

    In order to provide a rational background for the analysis of experimental observations of blast wave phenomena, the conservation equations governing their nonsteady flow field are formulated in a general manner, without the usual restrictions imposed by an equation of state, and with proper account taken, by means of source terms, of other effects which, besides the inertial terms that conventionally dominate these equations, can affect the flow. Taking advantage of the fact that a blast wave can be generally considered as a spatially one-dimensional flow field whose nonsteady behavior can be regarded, consequently, as a function of just two independent variables, two generalized blast wave coordinates are introduced, one associated with the front of the blast wave and the other with its flow field. The conservation equations are accordingly transformed into this coordinate system, acquiring thereby a comprehensive character, in that they refer then to any frame of reference, being applicable, in particular, to problems involving either space or time profiles of the gas-dynamic parameters in the Eulerian system, or time profiles in the Lagrangian system.

  6. Numerical simulation of armored vehicles subjected to undercarriage landmine blasts

    Science.gov (United States)

    Erdik, A.; Kilic, S. A.; Kilic, N.; Bedir, S.

    2015-05-01

    Landmine threats play a crucial role in the design of armored personnel carriers. Therefore, a reliable blast simulation methodology is valuable to the vehicle design development process. The first part of this study presents a parametric approach for the quantification of the important factors such as the incident overpressure, the reflected overpressure, the incident impulse, and the reflected impulse for the blast simulations that employ the Arbitrary Lagrangian-Eulerian formulation. The effects of mesh resolution, mesh topology, and fluid-structure interaction (FSI) parameters are discussed. The simulation results are compared with the calculations of the more established CONventional WEaPons (CONWEP ) approach based on the available experimental data. The initial findings show that the spherical topology provides advantages over the Cartesian mesh domains. Furthermore, the FSI parameters play an important role when coarse Lagrangian finite elements are coupled with fine Eulerian elements at the interface. The optimum mesh topology and the mesh resolution of the parametric study are then used in the landmine blast simulation. The second part of the study presents the experimental blast response of an armored vehicle subjected to a landmine explosion under the front left wheel in accordance with the NATO AEP-55 Standard. The results of the simulations show good agreement with the experimental measurements.

  7. Assessment, development, and testing of glass for blast environments.

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Sarah Jill

    2003-06-01

    Glass can have lethal effects including fatalities and injuries when it breaks and then flies through the air under blast loading (''the glass problem''). One goal of this program was to assess the glass problem and solutions being pursued to mitigate it. One solution to the problem is the development of new glass technology that allows the strength and fragmentation to be controlled or selected depending on the blast performance specifications. For example the glass could be weak and fail, or it could be strong and survive, but it must perform reliably. Also, once it fails it should produce fragments of a controlled size. Under certain circumstances it may be beneficial to have very small fragments, in others it may be beneficial to have large fragments that stay together. The second goal of this program was to evaluate the performance (strength, reliability, and fragmentation) of Engineered Stress Profile (ESP) glass under different loading conditions. These included pseudo-static strength and pressure tests and free-field blast tests. The ultimate goal was to provide engineers and architects with a glass whose behavior under blast loading is less lethal. A near-term benefit is a new approach for improving the reliability of glass and modifying its fracture behavior.

  8. Blast wave propagation and the influence of obstacles

    International Nuclear Information System (INIS)

    Pressure characteristics of blast waves simulating unconfined gas explosions are investigated through a series of laboratory-scale experiments and larger scale field tests. Initially, the distance attenuation and the degree of rotational symmetry close to the source was investigated for the gas filled latex balloons used in these experiments, and for the field tests, the influence of different atmospheric condtions has primarily been established by using high-explosives detonators. The interaction between the blast wave and different boundaries and obstacles have been investigated in both laboratory-scale and field tests, and it is shown, that the influence is a very localized effect, leaving the blast wave unaffected at larger distances. The interaction with groups of building-like structures has been investigated in laboratory-scale tests, and it is shown that the pressures measured on the obstacle surfaces apparently are affected by both reflection and diffraction of the incoming blast wave. Pressure distribution and reflection factors for a single wall has been determined in the field tests, and relatively large reflected pressures have been measured. Correspondingly large pressures have been measured at certain locations at a group of buildings. (author)

  9. Injection of heavy fuel oil into the blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Paloposki, T. [Helsinki Univ. of Technology, Otaniemi (Finland); Hakala, J.; Mannila, P.; Laukkanen, J. [Oulu Univ. (Finland)

    1996-12-31

    This study deals with the injection and combustion of heavy fuel oil in blast furnaces. The injection of the oil was studied experimentally in a small-scale test rig. The combustion of the oil was analysed with a commercial computer program for flow and combustion simulations. Results from computer simulations show that the combustion of the oil can be improved by decreasing the size of the oil drops and by enhancing the mixing between the oil drops and the hot blast. The devolatilization rate of the oil mainly depends on the size of the oil drops. The combustion rate of the volatiles mainly depends on the effectiveness of turbulent mixing with combustion air. Methods to decrease the size of the oil drops were sought in the experimental part of the study. Experimental results show that the size of the oil drops increases with increasing mass flow rate of the oil and decreases with increasing velocity of the hot blast. Methods to improve the mixing between the oil drops and the hot blast are suggested but have not yet been experimentally tested. (author) (4 refs.)

  10. Mechanical assessment of grit blasting surface treatments of dental implants.

    Science.gov (United States)

    Shemtov-Yona, K; Rittel, D; Dorogoy, A

    2014-11-01

    This paper investigates the influence of surface preparation treatments of dental implants on their potential (mechanical) fatigue failure, with emphasis on grit-blasting. The investigation includes limited fatigue testing of implants, showing the relationship between fatigue life and surface damage condition. Those observations are corroborated by a detailed failure analysis of retrieved fracture dental implants. In both cases, the negative effect of embedded alumina particles related to the grit-blasting process is identified. The study also comprises a numerical simulation part of the grit blasting process that reveals, for a given implant material and particle size, the existence of a velocity threshold, below which the rough surface is obtained without damage, and beyond which the creation of significant surface damage will severely reduce the fatigue life, thus increasing fracture probability. The main outcome of this work is that the overall performance of dental implants comprises, in addition to the biological considerations, mechanical reliability aspects. Fatigue fracture is a central issue, and this study shows that uncontrolled surface roughening grit-blasting treatments can induce significant surface damage which accelerate fatigue fracture under certain conditions, even if those treatments are beneficial to the osseointegration process. PMID:25173238

  11. New mathematical model for blast furnace burden distribution; Nuevo modelo matematico para la distribucion de carga en el horno alto

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, J.; Mochon, J.; Formoso, A.; Bueno, F. [Centro Nacional de Investigaciones Metalurgicas. CENIM. Madrid (Spain); Fernandez, B.; Sainz de Ayala, J. [ACERALIA. Gijon. (Spain)

    1998-10-01

    A mathematical model for burden distribution in the blast furnace, has been developed. A set of operational variables related with the charging system (Paul Wurth) plus other parameters related with the burden itself, such as ore and coke repose angles, weights discharged and the effect of the uprising gas, have been taken into account. These data are processed by modern computer tools. As a result, the burden distribution inside the blast furnaces is obtained. Every time that a charge is added to the blast furnace, the model updates the burden distribution. The approach employed is based on considering each burden layer described by a set of interrelated polynomials. It has been tested comparing its results with burden layers obtained in a physical model of the blast furnace (scale 1/10). After installation in Aceralia blast furnace B control computers, the model is currently being employed as a tool for process control. (Author) 3 refs.

  12. Blast dynamics at Mount St Helens on 18 May 1980

    Science.gov (United States)

    Kieffer, S.W.

    1981-01-01

    At 8.32 a.m. on 18 May 1980, failure of the upper part of the north slope of Mount St Helens triggered a lateral eruption ('the blast') that devastated the conifer forests in a sector covering ???500 km2 north of the volcano. I present here a steady flow model for the blast dynamics and propose that through much of the devastated area the blast was a supersonic flow of a complex multiphase (solid, liquid, vapour) mixture. The shape of the blast zone; pressure, temperature, velocity (Mach number) and density distributions within the flow; positions of weak and strong internal shocks; and mass flux, energy flux, and total energy are calculated. The shape of blast zone was determined by the initial areal expansion from the reservoir, by internal expansion and compression waves (including shocks), and by the density of the expanding mixture. The pressure within the flow dropped rapidly away from the source of the blast until, at a distance of ???11 km, the flow became underpressured relative to the surrounding atmosphere. Weak shocks within the flow subparallel to the east and west margins coalesced at about this distance into a strong Mach disk shock, across which the flow velocities would have dropped from supersonic to subsonic as the pressure rose back towards ambient. The positions of the shocks may be reflected in differences in the patterns of felled trees. At the limits of the devastated area, the temperature had dropped only 20% from the reservoir temperature because the entrained solids thermally buffered the flow (the dynamic and thermodynamic effects of the admixture of the surrounding atmosphere and the uprooted forest and soils into the flow are not considered). The density of the flow decreased with distance until, at the limits of the blast zone, 20-25 km from the volcano, the density became comparable with that of the surrounding (dirty) atmosphere and the flow became buoyant and ramped up into the atmosphere. According to the model, the mass flux per

  13. On Blasting Design of Quarrying in Yueshan for Exploiting Stone%月山采石场石料开采爆破设计

    Institute of Scientific and Technical Information of China (English)

    李发亮

    2012-01-01

    In this paper, the blasting design of quarrying in Yueshan for exploiting Stone is inU'oduced. Through the selecting design parameters of blasting and due to using presplit blasting, deep hole blasting, millisecond blasting outside hole, delayed blasting inside hole and overburden stripping for once in Yueshan Quarry, the good construction effect is obtained.%文中介绍了月山采石场石料开采爆破设计,通过对爆破设计参数的选择。采用周边预裂爆破及深孔爆破,应用孔外微差孔内延时爆破技术在月山采石场石料开采爆破开挖中采用了保护层一次性开挖。取得了良好的施工效果。

  14. MEASUREMENT IN BLAST HOLE STEM AND INFLUENCE OF STEMING MATERIAL ON BLASTING QUALITY

    OpenAIRE

    Mario Dobrilović; Zvonimir Ester; Branimir Janković

    2005-01-01

    Paper presents results of blast hole stem materials, that were conducted to assert best stem materials for surface blasting in quarry of technical / construction stone. Blasting has been performed with equal explosives and test-minefield parameters (length of the stem, volume of the explosive charge, mine-drill depth, and angle) on various sites / quarry. Results are guidelines in materials to be chosen in surface blasting of quarry works, adding to quality of mining works and reduction of co...

  15. Application of blasting vibration measurement to underground deep-hole blasting of a uranium deposit

    International Nuclear Information System (INIS)

    Aimed at the potential vibration damage to residents' houses on surface after underground deep-hole blasting of a uranium deposit in stope leaching, two real-time blasting vibration measurements were made. The safe distance and safety criterion of maximum charge weight on millisecond delay explosive in large-scale blasting of the uranium deposit were summed up. These data can provide the design basis for future large scale ore stacking by blasting. (authors)

  16. Mitigation of exploding-wire-generated blast-waves by aqueous foam

    Science.gov (United States)

    Liverts, M.; Ram, O.; Sadot, O.; Apazidis, N.; Ben-Dor, G.

    2015-07-01

    In this work, we implement an exploding wire technique to generate small-scale cylindrical blast waves in aqueous foam. The exploding wire system offers an easy to operate and effective tool for studying blast-wave/foam interaction related phenomena in real explosion scenarios. The mitigation of blast waves as a function of the thickness of the foam barrier is discussed and quantified. A fluid mixture pseudo-gas based numerical approach with the aid of the point explosion theory is used to separate the mitigation mechanisms into the near- and the far-field related groups and to analyze the contribution of each group to the overall losses of the blast wave energy.

  17. Skull Flexure from Blast Waves: A New Mechanism for Brain Injury with Implications for Helmet Design

    CERN Document Server

    Moss, William C; Blackman, Eric G

    2008-01-01

    Traumatic brain injury [TBI] has become the signature injury of current military conflicts. The debilitating effects of TBI on society are long-lasting and costly. Although the mechanisms by which impacts cause TBI have been well researched, the mechanisms by which blasts cause TBI are not understood. Various mechanisms, including impacts caused by the blast, have been investigated, but blast-induced deformation of the skull has been neglected. Through the use of hydrodynamical numerical simulations, we have discovered that non-lethal blasts can induce sufficient flexure of the skull to generate potentially damaging loads in the brain, even if no impact occurs. This mechanism has implications for the diagnosis of TBI in soldiers and the design of protective equipment such as helmets.

  18. The Mechanism and Application of Deep-Hole Precracking Blasting on Rockburst Prevention

    Directory of Open Access Journals (Sweden)

    Zhenhua Ouyang

    2015-01-01

    Full Text Available The mechanism of preventing rockburst through deep-hole precracking blasting was studied based on experimental test, numerical simulation, and field testing. The study results indicate that the deep-hole precracking could change the bursting proneness and stress state of coal-rock mass, thereby preventing the occurrence of rockburst. The bursting proneness of the whole composite structure could be weakened by the deep-hole precracking blasting. The change of stress state in the process of precracking blasting is achieved in two ways: (1 artificially break the roof apart, thus weakening the continuity of the roof strata, effectively inducing the roof caving while reducing its impact strength; and (2 the dynamic shattering and air pressure generated by the blasting can structurally change the properties of the coal-rock mass by mitigating the high stress generation and high elastic energy accumulation, thus breaking the conditions of energy transfer and rock burst occurrence.

  19. Blast furnace operation with pulverized coal injection at different technological conditions

    International Nuclear Information System (INIS)

    Efficiency of pulverized coal injection (PCI) at two blast furnaces (BFs) in Spain and Ukraine which operate at different burden and blast conditions has been analyzed using statistical methods, calculation of material and heat balances and mathematical model. Effect of PCI on the parameters of blast furnace operation, pig iron quality and also on interactions between process parameters has been studied. At high-grade burden and high parameters of the combined blast, dependence of coke consumption rate on PC amounts is linear up to a high rate of PCI. At unfavorable burden and technological conditions dependence of the main furnace operating parameters on PC rate has extreme character. High efficiency of PC use can be achieved at the different conditions due to optimization of the technological regime. (Author) 31 refs

  20. Teknologi Pembuatan Material Shot Blast untuk Mendukung Industri Pengecoran Logam Nasional

    Directory of Open Access Journals (Sweden)

    Fajar Nurjaman

    2009-01-01

    Full Text Available Shot blast material is a supporting material in foundry which is used at surface finishing process of metal casting. Recently, there is no one of national industry that produce shot blast material, in consequence, the purpose of this research is to lessen the dependence of using shot blast material import by making a shot blast material which improve its hardness exceed the shot blast material import. This research use the raw material from scrap iron with the following composition: C (3.2%, Si (1.18%, Mn (6.1%, Cu (0.35%, Fe (88.7%. The scrap is melted in induction furnace untill melt (hot metal, then the hot metal (1200 oC is tilted into a runner which is connected with pan crucible, which is consisted of 107 holes with diameter of each holes is 10 mm. Hot metal that is leave from the holes, is injected by pressurized water 1.1 atm with the velocity 0.8 m/s, untill obtained grains of shot blast material, then these grains goes into the water tank which it has temperature 40oC. From thermodynamic study, to avoid the happening of the explosion that is arising out because the effect of high temperature difference at injection process beetween water and hot metal, hence the comparison value beetween the mass of water and hot metal equal to 1:4.6. From this research is obtained shot blast material Ø0.8-3.2 mm with the metallography structure with martensite domination and dispersion of cementite and a little austenit. The hardness value of this material is 54.8 HRC, where this value is larger than shot blast material import (45-50 HRC. Abstract in Bahasa Indonesia: Material shot blast merupakan material pendukung pengecoran logam yang digunakan pada proses surface finishing benda cor logam. Saat ini belum ada satupun industri nasional yang memproduksi material shot blast, karena itu tujuan penelitian ini untuk mengurangi ketergantungan penggunaan material shot blast impor dengan membuat material shot blast yang nilai kekerasannya melebihi material

  1. From blast wave to observation

    NARCIS (Netherlands)

    H.J. van Eerten; R.A.M.J. Wijers

    2008-01-01

    Gamma-ray burst (GRB) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the GRB progenitor. We introduce a code to reconstruct spectra and light curves from arbitrary fluid configurations, maki

  2. Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiuhua; DUAN Zhongdong; ZHANG Chunwei

    2008-01-01

    The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA.The multi-material Eulerian and Lagrangian coupling algorithm was adopted.A fluid-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground,multiple ALE element for simulating air and TNT explosive material.Numerical simulations of the blast pressure wave propagation,structural dynamic responses and deformation,and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed.The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure.The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation.The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic deformation subjected to intensive blast waves,and columns lost carrying capacity,subsequently leading to the collapse of the whole structure.The approach coupling influence between structural deformation and fluid load well simulated the progressive collapse process of structures,and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.

  3. A Study on Nuclear Blast Overpressure on Buildings and other infrastructures using Geospatial Technology

    Directory of Open Access Journals (Sweden)

    D. Thirumalaivasan

    2012-01-01

    Full Text Available An Improvised Nuclear Device or nuclear bomb of yield 10 kiloton to 20 kiloton explodes in any major city due to terrorism or any other reason can cause catastrophic damages on the building's and other infrastructures and also shutting down of critical life-safety systems.. The explosion may produce blast overpressure, thermal radiation and harmful instant and delayed nuclear radiations. The buildings and other Civil Engineering structures may be highly vulnerabke due to the blast overpressure from the explosion and thermal radiation. In this present study Remote Sensing and Geographical Information System is effectively utilized to model the blast affected zone from the ground Zero of the study area. This study also introduces different emperical methods to estimate blast loads and structural response. The purpose is to describe the blast effects of a nuclear explosion, thereby informing people of the real dangers posed by nuclear weapons. Therefore, as a case study, we consider a hypothetical City as a target for detonation. Due to security reasons the data for existing City is not used for this study purpose. The study area is hypothetically detonated with a 15 kiloton yield nuclear explosion as surface blast and wind spped is assumed as 5 meters per second.

  4. Study of blast event propagation in different media using a novel ultrafast miniature optical pressure sensor

    Science.gov (United States)

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Zhang, Hongtao; Niezrecki, Christopher; Wang, Xingwei

    2011-06-01

    Traumatic brain injury (TBI, also called intracranial injury) is a high potential threat to our soldiers. A helmet structural health monitoring system can be effectively used to study the effects of ballistic/blast events on the helmet and human skull to prevent soldiers from TBI. However, one of the biggest challenges lies in that the pressure sensor installed inside the helmet system must be fast enough to capture the blast wave during the transient period. In this paper, an ultrafast optical fiber sensor is presented to measure the blast signal. The sensor is based on a Fabry-Pérot (FP) interferometeric principle. An FP cavity is built between the endface of an etched optical fiber tip and the silica thin diaphragm attached on the end of a multimode optical fiber. The sensor is small enough to be installed in different locations of a helmet to measure blast pressure simultaneously. Several groups of tests regarding multi-layer blast events were conducted to evaluate the sensors' performance. The sensors were mounted in different segments of a shock tube side by side with the reference sensors, to measure a rapidly increasing pressure. The segments of the shock tube were filled with different media. The results demonstrated that our sensors' responses agreed well with those from the electrical reference sensors. In addition, the home-made shock tube could provide a good resource to study the propagation of blast event in different media.

  5. Model experiment of rock blasting with single borehole and double free-surface

    Institute of Scientific and Technical Information of China (English)

    TIAN Jian-sheng; QU Fan-fei

    2009-01-01

    In order to improve the quality of laneways and tunnel excavation by drilling and blasting and by making effective use of explosive energy, a model experiment of rock blasting with a single borehole and a double free-surface was performed with the objective of studying the effect of parameters such as charge structure, free-surface and rock compressive strength on rock blasting. The model experiments indicate that: 1) the smaller the rock compressive strength and density, the more distinctive the cavity expanding action by blasting; 2) the powder factor in an air-decoupling charge structure is larger than that in a coupling charge structure, i.e., the explosive energy in an air-decoupling charge structure transferred to the rocks is less than that in a coupling charge structure; 3) a free-surface improves the utilizations of explosive energy; 4) an air-decoupling charge structure helps to maintain the integrity and stability of wall rock in controlled perimeter blasting, such as in roadways and tunnel excavation by drilling and blasting.

  6. Disability evaluation in acoustic blast trauma

    OpenAIRE

    Ganesan Raju

    2015-01-01

    Introduction: Acoustic blast trauma is different from Noise induced hearing loss. Blast trauma can damage the tympanic membrane, ossicles and cochlea singly or in combination. It produces immediate severe hearing loss and may be associated with tinnitus and vestibular symptoms. Hearing loss recovers spontaneously in many cases but may be permanent in 30-55% cases. Thirteen patients working in an explosive manufacturing unit in Andhra Pradesh were exposed to blast trauma at work place. All the...

  7. An Abridged Review of Blast Wave Parameters

    OpenAIRE

    Manmohan Dass Goel; Vasant A. Matsagar; Gupta, Anil K.; Steffen Marburg

    2012-01-01

    In case of blast loading on structures, analysis is carried out in two stages, first the blast loading on a particular structure is determined and second, an evaluation is made for the response of the structure to this loading. In this paper, a review of the first part is presented which includes various empirical relations available for computation of blast load in the form of pressure-time function resulting from the explosion in the air. Different empirical techniques available in th...

  8. PROGRESS IN THERMO-ABRASIVE BLASTING SYSTEMS

    OpenAIRE

    I.A. Gorlach

    2012-01-01

    ENGLISH ABSTRACT: Quality of surface preparation of components and structures for further painting and/or coating is important in many fields of engineering. One of the most widely used methods of surface preparation is abrasive blasting. In the last few years, a new method for surface preparation has evolved, namely thermo-abrasive blasting. This technique utilises a high enthalpy thermal jet, generated by the thermo-abrasive blasting gun, to propel abrasive particles. Thermo-abrasi...

  9. Alkaline carbonates in blast furnace process

    Directory of Open Access Journals (Sweden)

    P. Besta

    2014-10-01

    Full Text Available The production of iron in blast furnaces is a complex of physical, chemical and mechanical processes. The input raw materials contain not only metallic components, but also a number of negative elements. The most important negative elements include alkaline carbonates. They can significantly affect the course of the blast furnace process and thus the overall performance of the furnace. As a result of that, it is essential to accurately monitor the alkali content in the blast furnace raw materials. The article analyzes the alkali content in input and output raw materials and their impact on the blast furnace process.

  10. 干冰微粒喷射工艺对等离子喷涂金属涂层结构和性能的影响%Effect of Dry-ice Blasting on the Microstructure and Properties of Plasma-sprayed Metallic Coatings

    Institute of Scientific and Technical Information of China (English)

    董淑娟; 宋波; Bernard Hansz; 廖汉林; Christian Coddet

    2012-01-01

    干冰微粒喷射法被应用到大气等离子喷涂中以改善涂层的性能.文中采用等离子喷涂和干冰微粒喷射工艺在不锈钢基体表面制备了钢涂层,并研究了涂层的微观结构、孔隙率、温度、氧化、表面粗糙度和结合强度等性能.结果表明,由于干冰微粒喷射具有较高的冷却效率,加之干冰微粒撞击所产生的机械作用,等离子喷涂制备的钢涂层呈现出更致密的结构特征.相比于空气冷却制备的涂层,干冰微粒冷却制备的涂层含有更少的氧化物.另外,干冰微粒喷射工艺对基体的预处理使得涂层的结合强度提高了将近14%,这是由于干冰微粒喷射工艺对基体上吸附的有机物质具有清洁作用,主要基于干冰颗粒的热、机械和膨胀的综合效应.%Dry-ice blasting was applied to the atmospheric plasma spraying process for improving coating's properties. In this paper, the steel coating was plasma-sprayed combined with dry-ice blasting on the stainless substrate, and the properties of the coating including microstructure, porosity, temperature, oxidation, surface roughness, and adhesion strength were studied in detail. Results show that plasma-sprayed steel coating displays a denser structure because dry-ice blasting has better cooling efficiency and mechanical effect arising from the impact of dry ice pellets. Compared with the coating deposited by air cooling, the coating prepared by dry-ice blasting has less oxide. Additionally, the adhesion strength increases up to 14% after the pretreatment of dry-ice blasting. This result from the cleaning effect of dry-ice blasting on organic substances adsorbed on the substrate surface is a combination of thermal, mechanical and sublimating effect.

  11. Ritonavir and disulfiram have potential to inhibit caspase-1 mediated inflammation and reduce neurological sequelae after minor blast exposure.

    Science.gov (United States)

    Foley, Kevin; Kast, Richard E; Altschuler, Eric L

    2009-02-01

    Caspase-1 triggers cytokine release following acceleration-induced concussive head injury. Minor blast injury in which no physical tissue injury occurs, results in the release of cytokines in a similar fashion. Ritonavir, a generically available protease inhibitor with a benign short-term side-effect profile, has been shown to inhibit expression of caspase-1. We review the relevant literature and propose that ritonavir may be of benefit in reducing adverse neuropsychiatric outcomes and hastening recovery following mild blast injury. Further research in animal models of blast injury followed by clinical studies would determine whether this therapy is effective.

  12. Simultaneous imaging of two-dimensional electron density and air-flow distribution over air-blast decaying arc

    International Nuclear Information System (INIS)

    Sensitive Shack–Hartmann type laser wavefront sensors were applied to simultaneous imaging of two-dimensional electron density and air-flow distributions over decaying arc channels under air blasting with several pressures. Our experimental results showed that higher blasting pressures facilitated the rapid reduction of arc diameters and an increase in the electron densities around the gap centre due not only to the thermal pinch effect but also to air-flow disturbances, although there were no significant effects of the air blasting on the arc conductance. (paper)

  13. Discrete fiber-reinforced polyurea systems for infrastructure strengthening and blast mitigation

    Science.gov (United States)

    Carey, Natalia L.

    The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation. The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon tensile testing. The addition of glass fiber to a polymer coating provided improved stiffness and strength to the composite system while the polyurea base material provided ductility. The second paper evaluated the behavior of hybrid, plain, and steel fiber-reinforced concrete panels coated with various polyurea and DFRP systems under blast loading. Hybrid panels demonstrated higher blast mitigation performance compared to plain and steel fiber-reinforced concrete panels due to sacrificial hybrid layer. The addition of plain polyurea or DFRP systems on the tension side improved panel performance by containing fragmentation during a blast event. The third paper presents an analytical investigation conducted using the explicit finite element program LS-DYNA to model panel and coating response under blast loading. Several modeling solutions were undertaken and compared for concrete formulation. Modeling results were analyzed and compared to the experimental work to validate the conclusions. The final paper describes an internal equilibrium mechanics based model developed to predict the flexural capacity of reinforced concrete beams strengthened with various DFRP systems. The developed model was validated using

  14. Pyramiding blast, bacterial blight and brown planthopper resistance genes in rice restorer lines

    Institute of Scientific and Technical Information of China (English)

    JI Zhi-juan; Yang Shu-dong; ZENG Yu-xiang; LIANG Yan; YANG Chang-deng; QIAN Qian

    2016-01-01

    Rice blast, bacterial blight (BB) and brown planthopper (BPH) are the three main pests of rice. This study investigated pyr-amiding genes resistant to blast, BB and BPH to develop restorer lines. Ten new lines with blast, BB and/or BPH resistance genes were developed using marker-assisted selection (MAS) technique and agronomic trait selection (ATS) method. Only HR13 with resistance genes to blast, BB and BPH was obtained. In addition to blast and BB resistance, four lines (HR39, HR41, HR42, HR43) demonstrated moderate resistance to BPH, but MAS for BPH resistance genes were not conducted in developing these four lines. These data suggested that there were unknown elite BPH resistance genes in the Zhongzu 14 donor parent. A more effective defense was demonstrated in the lines withPi1 andPi2 genes although the weather in 2012 was favorable to disease incidence. Blast resistance of the lines with a single resistance gene,Pita, was easily inlfuenced by the weather. Overal, the information obtained through pyramiding multiple resistance genes on developing the restorer lines is helpful for rice resistance breeding.

  15. Blast furnace operating conditions manipulation for reducing coke consumption and CO{sub 2} emission

    Energy Technology Data Exchange (ETDEWEB)

    Bahgat, Mohamed; Abdel Halim, Khaled S.; El-Kelesh, Heba Ali; Nasr, Mahmoud I. [Central Metallurgical Research and Development Institute (CMRDI), Cairo (Egypt)

    2012-07-15

    A comparative reduction behavior of wuestite samples prepared from iron ore sinter was investigated to find the optimum way for reducing coke consumption and CO{sub 2} emission in blast furnace technology. A series of wuestite reduction experiments was carried out using different gas mixtures. A correlation between the experimental results and real data of blast furnaces at Egyptian Iron and Steel Company (EISCO) was demonstrated in order to optimize the coke consumption inside blast furnaces. Different theoretical models were applied on real data of blast furnaces to calculate the effect of operation parameters on the coke consumption. It was found that the wuestite reducibility can be controlled and enhanced using certain ratio of H{sub 2} and CO gases. Such kind of enhancement decreases the remaining quantity of unreduced wuestite which descends to the high temperature region of blast furnace. The theoretical analysis of real data using certain values of H{sub 2} and CO shows that increasing the amount of natural gas injection in blast furnace of EISCO will decrease the degree of direct reduction of iron oxide and consequently will decrease the amount of coke consumption. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. A Small-Group Activity Introducing the Use and Interpretation of BLAST

    Directory of Open Access Journals (Sweden)

    Peter D. Newell

    2013-08-01

    Full Text Available As biological sequence data are generated at an ever increasing rate, the role of bioinformatics in biological research also grows. Students must be trained to complete and interpret bioinformatic searches to enable them to effectively utilize the trove of sequence data available. A key bioinformatic tool for sequence comparison and genome database searching is BLAST (Basic Local Alignment Search Tool. BLAST identifies sequences in a database that are similar to the entered query sequence, and ranks them based on the length and quality of the alignment. Our goal was to introduce sophomore and junior level undergraduate students to the basic functions and uses of BLAST with a small group activity lasting a single class period. The activity provides students an opportunity to perform a BLAST search, interpret the data output, and use the data to make inferences about bacterial cell envelope structure. The activity consists of two parts. Part 1 is a handout to be completed prior to class, complete with video tutorial, that reviews cell envelope structure, introduces key terms, and allows students to familiarize themselves with the mechanics of a BLAST search. Part 2 consists of a hands-on, web-based small group activity to be completed during the class period. Evaluation of the activity through student performance assessments suggests that students who complete the activity can better interpret the BLAST output parameters % query coverage and % max identity. While the topic of the activity is bacterial cell wall structure, it could be adapted to address other biological concepts.

  17. Numerical Analysis of Blast Furnace Performance Under Charging Iron-Bearing Burdens With High Reducibility

    Institute of Scientific and Technical Information of China (English)

    CHU Man-sheng; GUO Xian-zhen; SHEN Feng-man; YAGI Jun-ichiro; NOGAMI Hiroshi

    2007-01-01

    The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply high-reducibility sinter and carbon composite agglomerates for practical application at a blast furnace.

  18. A parametric approach to shape field-relevant blast wave profiles in compressed-gas-driven shock tube.

    Science.gov (United States)

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1-3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68-1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is compared

  19. Silicon and manganese on rice resistance to blast

    Directory of Open Access Journals (Sweden)

    Isaías Severino Cacique

    2012-01-01

    Full Text Available Blast, caused by the fungus Pyricularia oryzae, is the most important fungal disease of rice. The effect of silicon (Si and manganese (Mn, and their interaction, on rice resistance to blast was investigated. Rice plants (cultivar "Metica 1" were grown in hydroponic solution with 0 or 2 mmol L-1 of Si and with 0.5, 2.5, and 10 mmol L-1 of Mn. Sixty-day-old plants were inoculated with a conidial suspension of P. oryzae and the incubation period (IP, the number of lesions (NL per cm² of leaf area, the lesion size (LS, and blast severity were evaluated. Blast severity was scored at 48, 72, 96, and 144 hours after inoculation and data were used to obtain the area under blast progress curve (AUBPC. Silicon concentration was significantly higher in leaf tissues of plants supplied with this element than on its absence, regardless of Mn rates. There was no significant difference in Si concentration among the Mn rates for both - Si and +Si treatments. The Mn concentration was significantly higher in the tissues of plants from the - Si treatment as compared to plants of the +Si treatment, but only at the rate of 10 mmol L-1 of Mn. There was a significant increase in Mn concentration as the rates of this micronutrient increased from 0.5 to 10 mmol L-1 regardless of the Si treatments. The IP significantly increased in the +Si treatment. The Mn rates had no effect on the IP regardless of the Si treatments. The NL was significantly lower in the presence of Si regardless of the Mn rates. The Mn rates had no effect on NL regardless of the Si treatments. The addition of Si to the nutrient solution significantly reduced both LS and AUBPC regardless of Mn rates. However, in the absence of Si, the values for LS and AUBPC were significantly lower at the Mn rate of 10 µmol L-1 as compared to the rate of 0.5 µmol L-1. Overall, the results from this study showed the potential of Si to decrease blast development on rice regardless of the foliar concentration of Mn.

  20. 30 CFR 56.6306 - Loading, blasting, and security.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Loading, blasting, and security. 56.6306... § 56.6306 Loading, blasting, and security. (a) When explosive materials or initiating systems are... persons or vehicles. (g) Work shall not resume in the blast area until a post-blast examination...

  1. Numerical simulation of stress for the blasting of foundation pit

    Institute of Scientific and Technical Information of China (English)

    FEI Hong-lu; ZHAO Xin-pu

    2008-01-01

    Through the simulation of explicit dynamic analysis software LS-DYNA,made an analysis to the particle velocity and the stress distribution of surrounding rock when the explosives blasting.Explicated the mechanical character of surrounding rock in the foundation pit blasting,provided a basis to set of blasting parameters and optimized the blasting construction.

  2. 30 CFR 75.1320 - Multiple-shot blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Multiple-shot blasting. 75.1320 Section 75.1320... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1320 Multiple-shot blasting... periods of 1,000 milliseconds or less shall be used. (d) When blasting in anthracite mines, each...

  3. 30 CFR 56.6605 - Isolation of blasting circuits.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Isolation of blasting circuits. 56.6605 Section... Extraneous Electricity § 56.6605 Isolation of blasting circuits. Lead wires and blasting lines shall be... sources of stray or static electricity. Blasting circuits shall be protected from any contact...

  4. 30 CFR 77.1304 - Blasting agents; special provisions.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting agents; special provisions. 77.1304... COAL MINES Explosives and Blasting § 77.1304 Blasting agents; special provisions. (a) Sensitized ammonium nitrate blasting agents, and the components thereof prior to mixing, shall be mixed and stored...

  5. 29 CFR 1926.909 - Firing the blast.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.909 Firing the blast. (a) A code of blasting signals equivalent to Table U-1, shall be posted on one or more... to stop traffic during blasting operations. (d) It shall be the duty of the blaster to fix the...

  6. 30 CFR 77.1910 - Explosives and blasting; general.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and blasting; general. 77.1910... COAL MINES Slope and Shaft Sinking § 77.1910 Explosives and blasting; general. (a) Light and power circuits shall be disconnected or removed from the blasting area before charging and blasting. (b)...

  7. On the Propagation and Interaction of Spherical Blast Waves

    Science.gov (United States)

    Kandula, Max; Freeman, Robert

    2007-01-01

    The characteristics and the scaling laws of isolated spherical blast waves have been briefly reviewed. Both self-similar solutions and numerical solutions of isolated blast waves are discussed. Blast profiles in the near-field (strong shock region) and the far-field (weak shock region) are examined. Particular attention is directed at the blast overpressure and shock propagating speed. Consideration is also given to the interaction of spherical blast waves. Test data for the propagation and interaction of spherical blast waves emanating from explosives placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure.

  8. Blast impact behaviour of concrete with different fibre reinforcement

    OpenAIRE

    Drdlová Martina; Čechmánek René; Řídký Radek

    2015-01-01

    The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer) of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concre...

  9. Design validation experiments for the key worker blast shelter

    International Nuclear Information System (INIS)

    Design calculations for the blast shelter included the effects of soil arching. In the past, soil arching has been ignored for dynamic loads at shallow burial depths; however, recent test data indicate structural loading is significantly reduced by arching, even at very shallow burial depths. The result is a more efficient structural design. Experiments to be conducted on 1/4-scale structural elements during June through October 1983 will provide loading and response design

  10. Detonation safety of blasting caps

    Institute of Scientific and Technical Information of China (English)

    谢兴华; 彭小圣

    2002-01-01

    By means of researching into sympathetic detonation of blasting detonators in air, the regular patterns are concluded from blasting detonators interaction with the shock loading. The aerial distribution of initiating ability of detonators looks like a butterfly. The initiating ability mainly consists of shock wave, explosive gases and fliers. But fundamental questions remain. When does shock wave take the leading role? When and how does the explosive gases or the fliers take function? For those questions, there is less quantitative research. Through the theoretic deduction of the overpressure, the energy calculation of fliers and the experiment of sympathetic detonation of detonators, we can learn the sympathetic detonation distances of several kinds of detonators and make an inquiry into the lateral initiating regulations of detonators. So, we can provide the base data for the research into no sympathetic detonation of herd blasting detonators and then control the detonation between them. Then we can make full use of detonators and reduce the frequency of accidents caused by detonators.

  11. The Next Generation BLAST Experiment

    CERN Document Server

    Galitzki, Nicholas; Angilè, Francesco E; Ashton, Peter; Beall, James A; Becker, Dan; Bradford, Kristi J; Che, George; Cho, Hsiao-Mei; Devlin, Mark J; Dober, Bradley J; Fissel, Laura M; Fukui, Yasuo; Gao, Jiansong; Groppi, Christopher E; Hillbrand, Seth; Hilton, Gene C; Hubmayr, Johannes; Irwin, Kent D; Klein, Jeffrey; Van Lanen, Jeff; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P; Mani, Hamdi; Martin, Peter G; Mauskopf, Philip; Nakamura, Fumitaka; Novak, Giles; Pappas, David P; Pascale, Enzo; Pisano, Giampaolo; Santos, Fabio P; Savini, Giorgio; Scott, Douglas; Stanchfield, Sara; Tucker, Carole; Ullom, Joel N; Underhill, Matthew; Vissers, Michael R; Ward-Thompson, Derek

    2014-01-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5 m carbon fiber mirror that is 40% wider than the BLASTPol mirror and ~3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 microns. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn coupled submillimeter detector arrays. The liquid he...

  12. Refractory Pellet for Hot Blast Stove

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Peng Xigao

    2011-01-01

    1 Scope This standard specifies the term,definition,classification,specification,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of refractory pellet for hot blast stove.This standard is applicable to refractory pellet for hot blast stove.

  13. Blast mitigation experimental and numerical studies

    CERN Document Server

    2013-01-01

    Presents experimental methods of material and structural response to dynamic blast loads Includes computational analysis of material and structural response to dynamic blast loads Offers mitigation measures for structures in various environments Relates lab experiments to larger field tests Features more than 150 illustrations

  14. The use of blast furnace slag

    Directory of Open Access Journals (Sweden)

    V. Václavík

    2012-10-01

    Full Text Available The paper presents the results of experimental research that dealt with the substitution of finely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on finely ground blast furnace slag were observed.

  15. Swift GRBs and the blast wave model

    NARCIS (Netherlands)

    P.A. Curran; A.J. van der Horst; R.L.C. Starling; R.A.M.J. Wijers

    2008-01-01

    The complex structure of the light curves of Swift GRBs has made their interpretation and that of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to constrain the blast wave parameters: electron energy distribution, p, density profile of the circumburst medium, k

  16. 30 CFR 58.610 - Abrasive blasting.

    Science.gov (United States)

    2010-07-01

    ... miners shall use in accordance with 30 CFR 56.5005 or 57.5005 respirators approved for abrasive blasting by NIOSH under 42 CFR part 84, or the operation shall be performed in a totally enclosed device with... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abrasive blasting. 58.610 Section...

  17. BLAST RESPONSE OF INCLINED RIGID WALLS%刚性防爆墙迎爆面荷载计算方法研究

    Institute of Scientific and Technical Information of China (English)

    洪武; 范华林; 金丰年; 徐迎

    2012-01-01

    防爆墙作为一种有效的防护措施在国内外重要工程中得到了广泛应用,研究防爆墙迎爆面荷载计算方法有助于防爆墙的科学设计和合理使用。该文采用数值模拟的方法,对不同倾斜角度刚性墙迎爆面压力荷载的计算方法及不同倾角墙体的抗爆效能进行了研究。分析了冲击波在垂直墙体、迎向以及背向炸药倾斜墙体上的反射、绕流以及荷载分布规律,总结出了不同工况时墙体荷载计算方法。研究发现背向炸药倾斜的墙体与垂直墙体以及迎向炸药倾斜的墙体具有几乎相同的防护效果,但墙体所承受的荷载要低于其他两者,合理的解释了工程中存在的防爆墙后倾现象的力学机制。%To effectively prevent the blast damage of buildings and structural elements through blast walls, an accurate prediction of the blast loads in terms of the peak pressures on blast walls is necessary. Numerical simulations were adopted to study the blast loads on blast walls with inclinations varying from 5°to 30°and their corresponding blast attenuation effects. Reflections and refractions of the blast wave from blast walls with inclinations were analyzed. The distribution and prediction equations of the blast loads on the blast walls were explored from the numerical analysis. It is concluded that the blast wave attenuation effects are similar for blast walls with different inclinations. When the blast wall is anticlockwise inclined, the maximum moment on the wall is much smaller, which reveals the mechanism of the anticlockwise inclined blast wails widely adopted in engineering.

  18. Study on the Mechanism of Adhesion Improvement Using Dry-Ice Blasting for Plasma-Sprayed Al2O3 Coatings

    Science.gov (United States)

    Dong, Shujuan; Song, Bo; Hansz, Bernard; Liao, Hanlin; Coddet, Christian

    2013-03-01

    The mechanisms of adhesion improvement of plasma-sprayed Al2O3 coatings using dry-ice blasting were investigated. In this study, the change of substrate surface characteristics in both the topography and the wettability due to the treatment of dry-ice blasting was mainly studied. The effect of dry-ice blasting on Al2O3 splat morphology with different treatment durations was also examined. The residual stress of plasma-sprayed Al2O3 coatings using dry-ice blasting was measured by curvature method and compared to that of coatings deposited with conventional air cooling. Based on these numerous assessment tests, it could be concluded that the adhesion improvement of Al2O3 coatings could be attributed to the cleaning effect of dry-ice blasting on different organic substances adsorbed on the substrates and the peening effect.

  19. A new non-uniform blast load model for SDOF method of one-way reinforced concrete slab

    OpenAIRE

    Wang S.-C.; Lu F; Zhang D; Wang W.; Tang F

    2012-01-01

    A new effective model for calculation of the equivalent uniform blast load for non-uniform blast load such as close-in explosion of a one-way square and rectangle reinforced concrete slab is proposed in this paper. The model is then validated using single degree of freedom (SDOF) system with the experiments and blast tests for square slabs and rectangle slabs. Test results showed that the model is accurate in predicting the explosive charge weight and stand-off distance to impose a given dama...

  20. Power Tillers for Demining: Blast Test

    Directory of Open Access Journals (Sweden)

    Emanuela Elisa Cepolina

    2008-11-01

    Full Text Available Power tillers are very simple and versatile machines with large scale diffusion in developing countries, where they are commonly used both for agriculture and for transportation purposes. A new integrated participatory approach that makes use of and improves local end-users knowledge has been used to design a new robotic system for humanitarian demining applications in Sri Lanka, using power tiller as core module. A demining machine composed by a tractor unit, a ground processing tool and a vegetation cutting tool is here presented together with results obtained from the first blast test on the preliminary version of tractor unit armouring. Different breakable connections between wheels and axle have been designed to cause physical detachment and interrupt the transmission of the shock wave released by the explosion of a mine under one wheel. Effects of explosions on different types of wheels and on the chassis have been recorded and commented.

  1. A study of combined particle and blast wave loading of structures

    Science.gov (United States)

    Elgy, I. D.; Pope, D. J.; Pickup, I. M.

    2006-08-01

    In structural dynamics there are many instances where an appreciation of the combined effect of particulate and air blast loading are essential if an accurate prediction of structural response is to be attained. Examples include: the loading of structures via the detonation of cased munitions; the interaction of blast waves and secondary fragmentation with internal building components after an external contact explosion and the loading of vehicle bellies via the detonation of mines buried in soil. As an analytical simplification, engineers often incorporate the effect of particulate loading by applying a load factor to calculations of the blast component alone. In some cases the fragmentation, can indeed be considered as merely incidental but in others, analysis and experiments have indicated that the presence of inert matter within or in close proximity to a detonated explosive can alter the magnitude, spatial distribution and duration of loading applied to a structure. This paper describes a series of numerical simulations, conducted using the AUTODYN hydrocode, in which the effect of detonating an explosive within a matrix of particles, and the subsequent blast and particulate interaction with a target, was simulated. The total momentum transferred to a target and the spatial momentum distribution is evaluated for both mines buried under soil and confined air blasts. The momentum transferred is investigated as a function of the technique used to model particulation and detonation proximity. These comparisons offer an insight into the mechanisms by which buried blast mines load structures and lead to explanations of differences observed in thin plates deforming under simulated mine blast attacks.

  2. Transcriptomic analyses of space-induced rice mutants with enhanced susceptibility to rice blast

    Science.gov (United States)

    Cheng, Zhenlong; Liu, Ming; Zhang, Meng; Hang, Xiaoming; Lei, Cailin; Sun, Yeqing

    Mutagenic factors of the space environment influence organisms in different aspects. To elucidate the transcriptomic effects of space flight, a space flight-induced rice mutant, 972-4, and its on-ground control, 972ck, were inoculated with rice blast pathogens. Compared to the control, the mutant exhibited reduced resistance to the rice blast pathogen CH45. Microarray technique was employed to analyze affected genes and revealed that 481 genes were expressed at higher levels in the mutant strain and 188 genes were expressed at higher levels in the control strain under normal growth conditions, indicating that transcriptomic changes of rice seeds are induced by the space environment. After inoculation with the rice blast pathogen CH45, however, 2680 genes were differentially expressed in 972ck and 1863 genes were differentially expressed in 972-4. In addition, disease evaluation indicated that the control strain 972ck is more resistant to the rice blast pathogen CH45 than mutant strain 972-4. In addition, genes in both strains that were co-regulated after blast inoculation account for only 36.8% and 53.3% of the genes expressed in 972ck and 972-4, respectively. A large percentage of blast-regulated genes were not consistently expressed in 972-4 and 972ck, and the mutant and control strains exhibit different gene expression patterns after blast inoculation. Interestingly, 84 genes constitutively expressed higher in 972ck were up-regulated by blast inoculation, and 105 genes that were expressed at constitutively higher levels in 972-4 were down-regulated by blast inoculation. Of the differentially expressed, 7 encoded genes associated with pathogen resistance. Taken together, our results suggest that gene expression patterns are different between a space flight-induced rice mutant and its on-ground control, and the differential expression of resistance genes may be a potential mechanism that modulates the resistance of 972-4 to rice blast. Our results also suggest

  3. Energy absorption capabilities of composite sandwich panels under blast loads

    Science.gov (United States)

    Sankar Ray, Tirtha

    , ET) was suggested to compare energy absorption capabilities of the structures under blast loading. In addition, AEweb/ET (where AEweb is the energy absorbed by the middle core) was also employed to evaluate the energy absorption contribution from the web. Taking advantage of FEA and the simplified analytical model, the influences of material properties as well as core architectures and geometries on energy absorption capabilities (quantified by AET/ ET and AEweb/E T) were investigated through parametric studies. Results from the material property investigation indicated that density of the front face sheet and strength were most influential on the energy absorption capability of the composite sandwich panels under blast loading. The study to investigate the potential effectiveness of energy absorbed via inelastic deformation compared to energy absorbed via progressive failure indicated that for practical applications (where the position of bomb is usually unknown and the panel is designed to be the same anywhere), the energy absorption via inelastic deformation is the more efficient approach. Regarding the geometric optimization, it was found that a core architecture consisting of vertically-oriented webs was ideal. The optimum values for these parameters can be generally described as those which cause the most inelasticity, but not failure, of the face sheets and webs.

  4. Effects of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag

    Science.gov (United States)

    Zhang, Li; Zhang, Wu; Zhang, Ju-hua; Li, Guang-qiang

    2016-09-01

    The influences of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag were investigated. After oxidation, most of the Ti component in the slag was enriched into the perovskite phase, which served as the Ti-rich phase during the crystallization process. The phase transformation, occurrence state, and the interface of the Ti component were observed to be affected by the addition of different types of agents. During the oxidation process, titanaugite and Ti-rich diopside phases gradually transformed into non-Ti phases (anorthite: CaMgSi2O6 and CaAl2Si2O8) in the form of dendrites or columns, which were observed to be distributed at the surface of the perovskite phase. Several more cracks appeared along the grain boundaries of the perovskite phase after the addition of P2O5, facilitating the liberation of the perovskite phase. Composite additives combining both an acid and a base, such as CaO + CaF2 or P2O5 + CaF2, were used. We observed that the disadvantages of using single additives were successfully overcome.

  5. Amorphous and crystalline blast furnace slag

    International Nuclear Information System (INIS)

    Full text: One of the by-products of iron production from a blast furnace is the slag, Generally 250-300 kg of slag is produced per ton of iron. Liquid blast furnace slag can either be cooled quickly by quenching in a granulator or more slowly in air. The air-cooled product is crushed and sized for use as an aggregate in concrete. The granulated slag is ground to form ground granulated slag, which is a cost-effective supplementary cementitious material. Blends of ground granulated slag and Portland cement produce a cementitious paste that is more resistant to chloride penetration than pastes made from the Portland cement alone. In this study neutron diffraction techniques were used to examine samples of air-cooled and granulated slags from Australian Steel Mill Services stock piles at Port Kembla. Sourced from the same blast furnace, the materials should be expected to posses similar elemental chemistry. The mineral compositions would be different due to the rate of cooling each slag was subjected to. Samples, 15 grams in mass, were mounted in a vanadium can and diffraction patterns were measured using the SLAD instrument on the Reactor R-2 at the Studvik Neutron Research Laboratory in Sweden. The diffraction patterns were transformed into radial distribution functions using the reverse Monte Carlo program, MCGR. The granulated slag showed no diffraction peaks while the air cooled slag showed a crystalline product that can be identified by x-ray diffraction. The radial distribution functions showed differences that were consistent with the granulated slag being amorphous and the air-cooled slag crystalline. Both slag samples showed peaks in the radial distribution function at 1.8 Angstroms and 2.8 Angstroms. The greatest anomaly was a feature about 2.5 Angstroms found only in the radial distribution function for the granulated slag. This demonstration showed that there are differences in the short range bonding between the two compounds. We are currently

  6. Preliminary report on the rice blast resistance of space-induced mutants derived from rice cultivar 'Taihang-68'

    International Nuclear Information System (INIS)

    To screen the blast resistance mutants, the resistance of SP1 progenies derived from rice variety Taihang-68 were evaluated after satellite flight by representative blast isolate GD0193 which had a broad pathogenic spectra, and then primary genetic analysis of resistant mutants and mapping of resistance gene, as well as resistance spectra at seedling and neck blast resistance at maturity were performed. The results showed that space-mutation was effective method to change the blast resistance of Taihang-68. The screened resistant mutants TH1 and TH2 showed that resistance to isolate GD0193 no disjunction and separation respectively, and the resistance separation ratio of TH2 indicated that its resistance was controlled by one pair of major genes, which was preliminary mapped on the long arm of chromosome 11. In blast resistance spectra and neck blast resistance, TH1 and TH2 were both enhanced remarkable compared with the wild-type at seedling and maturity, and their resistance could be inherited, the blast resistance of these two mutants were also increased comparing with several main cultivars in South China. (authors)

  7. Analysis of Blast Wave Propagation Inside Tunnel

    Institute of Scientific and Technical Information of China (English)

    LIU Jingbo; YAN Qiushi; WU Jun

    2008-01-01

    The explosion inside tunnel would generate blast wave which transmits through the longi tudinal tunnel.Because of the close-in effects of the tunnel and the reflection by the confining tunnel structure,blast wave propagation inside tunnel is distinguished from that in air.When the explosion happens inside tunnel,the overpressure peak is higher than that of explosion happening in air.The continuance time of the biast wave also becomes longer.With the help of the numerical simu lation finite element software LS-DYNA.a three-dimensional nonlinear dynamic simulation analysis for an explosion experiment inside tunnel was carried out.LS-DYNA is a fully integrated analysis program specifically designed for nonlinear dynamics and large strain problems.Compared with the experimental results.the simulation results have made the material parameters of numerical simulation model available.By using the model and the same material parameters,many results were adopted by calculating the model under different TNT explosion dynamites.Then the method of dimensional analysis was Used for the Simulation resufts.AS Overpressures of the explosion biast wave are the governing factor in fhe tunnel responses.a formula for the explosion biast wave overpressure at a certain distance from the detonation center point inside the tunnel was de rived by using the dimensional analysis theory.By cornparing the results computed by the fromula with experimental results which were obtained before.the formula was proved to be very applicable at some instance.The research may be helpful to estimate rapidly the effect of internal explosion of tunnel on the structure.

  8. Simulation of the Reflected Blast Wave froma C-4 Charge

    Energy Technology Data Exchange (ETDEWEB)

    Howard, W M; Kuhl, A L; Tringe, J W

    2011-08-01

    The reflection of a blast wave from a C4 charge detonated above a planar surface is simulated with our ALE3D code. We used a finely-resolved, fixed Eulerian 2-D mesh (167 {micro}m per cell) to capture the detonation of the charge, the blast wave propagation in nitrogen, and its reflection from the surface. The thermodynamic properties of the detonation products and nitrogen were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. Computed pressure histories are compared with pressures measured by Kistler 603B piezoelectric gauges at 8 ranges (GR = 0, 2, 4, 8, 10, and 12 inches) along the reflecting surface. Computed and measured waveforms and positive-phase impulses were similar, except at close-in ranges (GR < 2 inches), which were dominated by jetting effects.

  9. Thermal Spray Coatings for Blast Furnace Tuyere Application

    Science.gov (United States)

    Pathak, A.; Sivakumar, G.; Prusty, D.; Shalini, J.; Dutta, M.; Joshi, S. V.

    2015-12-01

    The components in an integrated steel plant are invariably exposed to harsh working environments involving exposure to high temperatures, corrosive gases, and erosion/wear conditions. One such critical component in the blast furnace is the tuyere, which is prone to thermal damage by splashing of molten metal/slag, erosive damage by falling burden material, and corrosion from the ensuing gases. All the above, collectively or independently, accelerate tuyere failure, which presents a potential explosion hazard in a blast furnace. Recently, thermal spray coatings have emerged as an effective solution to mitigate such severe operational challenges. In the present work, five different coatings deposited using detonation spray and air plasma spray techniques were comprehensively characterized. Performance evaluation involving thermal cycling, hot corrosion, and erosion tests was also carried out. Based on the studies, a coating system was suggested for possible tuyere applications and found to yield substantial improvement in service life during actual field trials.

  10. Damage Assessment for Buried Structures Against Internal Blast Load

    Institute of Scientific and Technical Information of China (English)

    MA Guowei; HUANG Xin; LI Jianchun

    2008-01-01

    The soil-structure interaction(SSI)decoupling is applied to simplify buried structure against internal blast lpad as spring effect.Shear failure.bending failure and Combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element.The critical equations for shear and bending failure are derived respectively.Pressure impulse diagrams are accordingly developed to assess damage of the buried structures against internal blast lpad.Cornparison is done to show influences of soil-structure interaction and shear to-bending strength ratio of a structural element.A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure.

  11. Role of mini-blast furnaces in South East Asia

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmanan, V.K.; Pfeifer, H.C. [Tata Korf Engineering Services, Calcutta (India)

    1997-12-31

    Mini blast furnaces (MBFs) are a small, economic, proven iron production technology. They are widely used in mini integrated steel plants and are likely to be yet more widely used. MBFs are described, contrasting them with direct reduction technology and with conventional blast furnaces. Besides their economic advantages they also cause few adverse environmental effects. These features have made MBF plant popular in Brazil and India in recent years, and plants are also planned in Indonesia. MBF-EOF (Energy optimising furnace) plants are also gaining popularity. They are useful where power is scarce and expensive. MBF-EOF plants are under construction in India and Indonesia. The future use of MBF plants in Asia is discussed. 9 refs., 2 figs., 5 tabs.

  12. Alkali-activated blast furnace slag-zeolite cements and concretes

    International Nuclear Information System (INIS)

    The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

  13. Electrochemical and morphological analyses on the titanium surface modified by shot blasting and anodic oxidation processes

    International Nuclear Information System (INIS)

    In recent years, many surface modification processes have been developed in order to induce the osseointegration on titanium surface and thus to improve the implants' biocompatibility. In this work, Ti surface has been modified by shot blasting followed by anodic oxidation process in order to associate the good surface characteristics of both processes to obtain a rough and porous surface able to promote the titanium surface bioactivity. Commercially pure titanium (grade 2) plates were used on the surface treatments that were as follows: Shot blasting (SB) performed using alumina (Al2O3) particles, and anodic oxidation (AO) using NaOH electrolyte. The morphology, structural changes and the open-circuit potentials (OCP) of the surfaces were analyzed. It can be observed that an increase on the roughness of the blasted surface and a rough and porous surface happens after the AO process. The anodic film produced is thin and followed the blasted surface topography. It can be observed that there are small pores with regular shape covering the entire surface. X-ray diffraction results showed the presence of the anatase and rutile phases on the blasted and anodized surface after heat treatment at 600 °C/1 h. Concerning electrochemical measurements, when the different samples were submitted to open-circuit conditions in a physiological electrolyte, the protective effect increases with the oxidation process due to the oxide layer. When the surface was blasted, the OCP was more negative when compared with the Ti surface without surface treatments. - Highlights: ► A combination of shot blasting and anodic oxidation surface treatments is proposed. ► Both processes produced an increase in roughness compared to the polished surface. ► The combination of processes produced a rough and porous surface. ► Open circuit results show that the protective effect increases with oxidation process. ► The combination of processes presents the better results in this work

  14. Coke Reactivity in Simulated Blast Furnace Shaft Conditions

    Science.gov (United States)

    Haapakangas, Juho; Suopajärvi, Hannu; Iljana, Mikko; Kemppainen, Antti; Mattila, Olli; Heikkinen, Eetu-Pekka; Samuelsson, Caisa; Fabritius, Timo

    2016-08-01

    Despite the fact that H2 and H2O are always present in the gas atmosphere of a blast furnace shaft, their role in the solution-loss reactions of coke has not been thoroughly examined. This study focuses on how H2 and H2O affect the reaction behavior and whether a strong correlation can be found between reactivity in the conditions of the CRI test (Coke Reactivity Index) and various simulated blast furnace shaft gas atmospheres. Partial replacement of CO/CO2 with H2/H2O was found to significantly increase the reactivity of all seven coke grades at 1373 K (1100 °C). H2 and H2O, however, did not have a significant effect on the threshold temperature of gasification. The reactivity increasing effect was found to be temperature dependent and clearly at its highest at 1373 K (1100 °C). Mathematical models were used to calculate activation energies for the gasification, which were notably lower for H2O gasification compared to CO2 indicating the higher reactivity of H2O. The reactivity results in gas atmospheres with CO2 as the sole gasifying component did not directly correlate with reactivity results in gases also including H2O, which suggests that the widely used CRI test is not entirely accurate for estimating coke reactivity in the blast furnace.

  15. FACILITIES PLANNING WORKSHOP FOR BLASTING SUPPORT THE ACTIVITY OF DEVELOPMENT AND REPAIR SHIP IN PT. JASA MARINA INDAH UNIT II

    Directory of Open Access Journals (Sweden)

    Samuel Samuel

    2012-07-01

    Full Text Available Blasting in the process of planning the workshop production of new building and ship repair to play a role in providing blasting and paint on the block that will be of erection. As a result of blasting workshop facilities that do not have resulted in low production capacity that can be achieved by this workshop, namely three block ships per month. Capacity blasting and paint shop in this low resulted in low productivity process stage (stage the previous workshops which of course result in a decrease in vessel productivity in general.                 In penelitiaan aims to plan for blasting and paint shop facility which has been adjusted to the planned production capacity of PT. JASA MARINA INDAH II units.                 In this study it - thing to note is to understand the data - the data field for research conducted in terms of both technical and economic terms, with the blasting and paint shop facilities on the construction or repair of ships that have been planned, then the effectiveness of the work and production flow at. Jasa Marina Indah II units can be known.                 Based on the analysis and calculation of both technical and economical it can be identified by the workshop on the process of blasting Blasting efficiency is obtained for 2.55 hours, at 10.16 hours during the painting process, while economical in terms of labor costs can be reduced blasting cost is Rp.930000    for          paint       and         Rp.1.23million

  16. BARYON LOADED RELATIVISTIC BLAST WAVES IN SUPERNOVAE

    International Nuclear Information System (INIS)

    We provide a new analytic blast wave solution which generalizes the Blandford-McKee solution to arbitrary ejecta masses and Lorentz factors. Until recently relativistic supernovae have been discovered only through their association with long-duration gamma-ray bursts (GRBs). The blast waves of such explosions are well described by the Blandford-McKee (in the ultra-relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows, as the ejecta mass is negligible in comparison to the swept-up mass. The recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, opens up the possibility of highly baryon loaded, mildly relativistic outflows which remains in nearly free-expansion phase during the radio afterglow. In this work, we consider a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating adiabatically due to its collision with the pre-explosion circumstellar wind profile of the progenitor. We compute the synchrotron emission from relativistic electrons in the shock amplified magnetic field. This models the radio emission from the circumstellar interaction of a CEDEX. We show that this model explains the observed radio evolution of the prototypical SN 2009bb and demonstrate that SN 2009bb had a highly baryon loaded, mildly relativistic outflow. We discuss the effect of baryon loading on the dynamics and observational manifestations of a CEDEX. In particular, our predicted angular size of SN 2009bb is consistent with very long baseline interferometric (VLBI) upper limits on day 85, but is presently resolvable on VLBI angular scales, since the relativistic ejecta is still in the nearly free-expansion phase.

  17. Appraise a combination of fungicides against blast and sheath blight diseases of paddy (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar M K

    2014-02-01

    Full Text Available In present study various fungicides were screened against blast (leaf and neck and sheath blight disease of rice. Among them, Conika 50% WP (Kasugamycin 5% + Copper Oxychloride 45% WP, Dhanucop Team (Tricyclazole 75% WP and RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG were found effective against blast diseases. While, the seed treatment fungicide Isotianil SC 200 and its combination with Trifloxystrobin 500 SC were found least effective against leaf and neck blast diseases. However, in case of sheath blight, Thifluzamide 24% SC, RIL-068/F1 48 WG (Kresoxim methyl 40% + Hexaconazole 8% WG, Propiconazole 25% EC (Tilt, Tricyclazole 75% WP (Beam and a new combination fungicide, Fluxapyroxad 62.5 g/l + Epoxiconazlle 62.5 g/l EC (Adexar w/v EC were found effective.

  18. Evaluation of efficiency of working time of equipment in blast furnace department

    Directory of Open Access Journals (Sweden)

    E. Kardas

    2012-12-01

    Full Text Available Purpose: The main aim of the paper is the evaluation of efficiency of working time of equipment in blast furnace department with the use of Overall Equipment Effectiveness (OEE and PAMCO method.Design/methodology/approach: The investigation was made for blast furnace department in Polish steel plant. Two methods: OEE and PAMCO was used. The analysis covers the period of 7 years. The analysis was made based on different data: different types of time connected whit work of blast furnaces, interruption in blast furnace work, level of pig iron production, unit production time and quantity of non-conformance production.Findings: Performed research made it possible to determine the level of efficiency of blast furnace department. It can be concluded that working time in this department is used efficient. Factors that reduce efficiency are usually not-dependent on the company: mainly are connected with the situation on the steel market.Research limitations/implications: It is necessary to continue the research in order to assess individual blast furnaces. That analysis may enable to show if these units has the same level of efficiency and if they are affected by the same factors in the same way.Practical implications: Optimal utilization of capacity and working time of machines and equipment are important for the reduction of production costs. Use of OEE and PAMCO methods helps to assess the level of efficiency of working time and allow to find factors that has great importance for level of efficiency.Originality/value: Results of this analysis can be taken into consideration by blast furnace department under study. Analysis can help to assess the level of efficiency and find factors that influence on it.

  19. Experimental animal models for studies on the mechanisms of blast induced neurotrauma

    Directory of Open Access Journals (Sweden)

    Mårten eRisling

    2012-04-01

    Full Text Available A blast injury is a complex type of physical trauma resulting from the detonation of explosive compounds and has become an important issue due to the use of improvised explosive devices (IED in current military conflicts. Blast induced neurotrauma (BINT is a major concern in contemporary military medicine and includes a variety of injuries that range from mild to lethal. BINT is characterized by extreme forces and their complex propagation. Modern body protection and the development of armored military vehicles can be assumed to have changed the outcome of BINT. Primary blast injuries are caused by overpressure waves whereas secondary, tertiary and quaternary blast injuries can have more varied origins such as the impact of fragments, abnormal movements or heat. The characteristics of the blast wave can be assumed to be significantly different in open field detonations compared to explosions in a confined space, such an armored vehicle. Important parameters include peak pressure, duration and shape of the pulse. Reflections from walls and armor can make the prediction of effects in individual cases very complex. Epidemiological data do not contain information of the relative importance of the different blast mechanisms. It is therefore important to generate data in carefully designed animal models. Such models can be selective reproductions of a primary blast, penetrating injuries from fragments, acceleration movements or combinations of such mechanisms. It is of crucial importance that the physical parameters of the employed models are well characterized so that the experiments can be reproduced in different laboratory settings. Ideally, pressure recordings should be calibrated by using the same equipment in several laboratories. With carefully designed models and thoroughly evaluated animal data it should be possible to achieve a translation of data between animal and clinical data. Imaging and computer simulation represent a possible link

  20. Genetic structure and virulence diversity of Pyricularia grisea in breeding for rice blast resistance

    International Nuclear Information System (INIS)

    Rice blast caused by Pyricularia grisea Sacc. is the main production constraint in rice worldwide. Development of resistant cultivars has been the preferred means of controlling this disease; however, resistance is defeated by the pathogen shortly after cultivar release. The blast pathogen population in Colombia's rice growing areas has been grouped into six genetically different families named SRL-1 to SRL-6 using DNA fingerprinting. The spectrum of virulence of isolates within each family is highly similar, differing mainly in signel virulences. Although the six genetic families of the fungus share a high number of virulence factors, high specific interaction between some avirulence/virulence factors in the pathogen and resistance genes in the host has been observed. This specific interaction is the basis for selecting the progenitors to be included in a breeding programme aimed at obtaining more durable blast resistance. Combinations of genes showing complementary resistance to different genetic families of the fungus should exclude any compatible interaction with a blast isolate. Identification of complementary resistance genes is based on detecting those virulence factors whose combinations in individual isolates within the pathogen population have a frequency near zero. It is assumed that certain virulence combinations in the blast pathogen may confer a low fitness or have a deleterious effect on the fungus, reducing its frequency in nature. The frequency of the virulence factors to the resistance genes Pi-1 and Pi-2 present independently in two different near isogenic lines is high in the blast fungus population of genetic families SRL-5 and SRL-1, respectively. The two genes show complementary resistance that excludes all the genetic families of the fungus, and no isolate with a combination of the two virulence genes infecting both isogenic lines has been detected. Induced mutations can be a useful technique for producing rice lines with specific resistance

  1. Assessment of the Effect of Fungicide and Seed Rate on the Incidence of Leaf Blast (Magnaphorthe Grisea, On the Growth of Foxtail Millet (Setaria Italica (L. P. BEAUV in North-eastern Nigeria

    Directory of Open Access Journals (Sweden)

    Z. G. S. Turaki

    2014-02-01

    Full Text Available In 2007 a multilocational trial was conducted in a split-plot using randomized complete block University of Maiduguri and Gashua Farm station to assess the effects of fungicide and seed rate on the incidence of leaf blast (Magnaphorte grisea, on the growth and yield of foxtail millet in the Northeastern Nigeria. The results showed that the lowest disease incidence of 20.8% and 0.4% were recorded from 100% recorded significantly (P < 0.05 the highest disease incidence of 80.0% and 64.3% at Maiduguri and Gashua respectively. The highest plant height and panicle length were recorded from plants grown at fungicide seed treatment ranging from 80-100% at seed rate of 5.0kg/ha. The lowest plant height and panicle length were obtained from plants grown from the untreated seed tate of 12.5kg/ha and while the lowest grain yields were recorded from untreated seed rate of 5.0kg/h at Maiduguri and Gashua respectively.

  2. EFEITO DE FUNGICIDAS NO CONTROLE DE BRUSONE (Pyricularia oryzae E MANCHA PARDA (Helminthosporium oryzae NO ARROZ EFFECT OF FUNGICIDES IN THE CONTROL OF RICE BLAST Pyricularia oryzae AND Helminthosporium oryzae

    Directory of Open Access Journals (Sweden)

    Wilson Ferreira de Oliveira

    2007-09-01

    Full Text Available

    Foi avaliado, a nível de campo, o efeito dos fungicidas ethiltrianol e edifienphos no controle de brusone (Pyricularia oryzae Cav. e Helminthosporium oryzae Breda de Haan na cultura do arroz, variedade IAC - 47. Os fungicidas foram pulverizados uma ou duas vezes, em diferentes concentrações a partir da emissão das panículas. Os resultados apurados indicaram que quanto a lesões nas panículas, nos grãos e produtividade, não houve diferença significativa entre os tratamentos. Com relação ao parâmetro lesões nas folhas bandeiras houve diferença entre todos os tratamentos com fungicidas e a testemunha.

    The effect of the fungicides ethiltrianol and edifenphos was evaluated, on level of field, aiming control rice blast (Pyricularia oryzae and Helminthosporium oryzae in variety IAC - 47. The fungicides were pulverized one or two times in different concentrations in the stage of panicles emission. The results showed that, as to infection level in the panicles, grain lesions and productivity there was no significant statistical difference between treatments. Refering to infection level in the banner leaves, there was significant statistical difference between treatments and the control.

  3. Predicting the Impact of Rock Blasting on Building Structures at Awunakrom in the Ahanta West District of Ghana

    OpenAIRE

    K.J. Bansah; E. Assan; G. Galecki

    2014-01-01

    Blasting is an important process after drilling is completed in hard rock mining. It involves placing explosives in drill holes and detonating them to cause explosion. The energy released during this process fragments the rocks into sizes for desired end use. The detonation of these explosives may produce undesirable effects such as ground vibration which is capable of causing damage to building structures. It is therefore, necessary to conduct blast impact studies to determine potential impa...

  4. Analysis of post-blasting source mechanisms of mining-induced seismic events in Rudna copper mine, Poland

    OpenAIRE

    Caputa Alicja; Talaga Adam; Rudziński Łukasz

    2015-01-01

    The exploitation of georesources by underground mining can be responsible for seismic activity in areas considered aseismic. Since strong seismic events are connected with rockburst hazard, it is a continuous requirement to reduce seismic risk. One of the most effective methods to do so is blasting in potentially hazardous mining panels. In this way, small to moderate tremors are provoked and stress accumulation is substantially reduced. In this paper we present an analysis of post-blasting e...

  5. Blast Desing With Optimal Delaying Intervals for use of Commercial Cartriigs Explosives at Banjani Mines –Skopje

    OpenAIRE

    Stefanov, Mile; Dambov, Risto; Dambov, Ilija

    2011-01-01

    In this paper are presented some blasting series which are prepare with commercial explosives form Detonit - Trayal corporation. We give some characteristics of this explosives, ways of use and effects form this blasting series. For use as a comercial explosive was prepare vocational expertise has been carried out for drilling parameters, hole charging mode and ignition pattern as well. Using of commercial explosives is in a marbleized limestone media which are heterogeneous an...

  6. Blast Injuries: From Improvised Explosive Device Blasts to the Boston Marathon Bombing.

    Science.gov (United States)

    Singh, Ajay K; Ditkofsky, Noah G; York, John D; Abujudeh, Hani H; Avery, Laura A; Brunner, John F; Sodickson, Aaron D; Lev, Michael H

    2016-01-01

    Although most trauma centers have experience with the imaging and management of gunshot wounds, in most regions blast wounds such as the ones encountered in terrorist attacks with the use of improvised explosive devices (IEDs) are infrequently encountered outside the battlefield. As global terrorism becomes a greater concern, it is important that radiologists, particularly those working in urban trauma centers, be aware of the mechanisms of injury and the spectrum of primary, secondary, tertiary, and quaternary blast injury patterns. Primary blast injuries are caused by barotrauma from the initial increased pressure of the explosive detonation and the rarefaction of the atmosphere immediately afterward. Secondary blast injuries are caused by debris carried by the blast wind and most often result in penetrating trauma from small shrapnel. Tertiary blast injuries are caused by the physical displacement of the victim and the wide variety of blunt or penetrating trauma sustained as a result of the patient impacting immovable objects such as surrounding cars, walls, or fences. Quaternary blast injuries include all other injuries, such as burns, crush injuries, and inhalational injuries. Radiography is considered the initial imaging modality for assessment of shrapnel and fractures. Computed tomography is the optimal test to assess penetrating chest, abdominal, and head trauma. The mechanism of blast injuries and the imaging experience of the victims of the Boston Marathon bombing are detailed, as well as musculoskeletal, neurologic, gastrointestinal, and pulmonary injury patterns from blast injuries.

  7. Explosive signatures: Pre & post blast

    Science.gov (United States)

    Bernier, Evan Thomas

    Manuscripts 1 and 2 of this dissertation both involve the pre-blast detection of trace explosive material. The first manuscript explores the analysis of human hair as an indicator of exposure to explosives. Field analysis of hair for trace explosives is quick and non-invasive, and could prove to be a powerful linkage to physical evidence in the form of bulk explosive material. Individuals tested were involved in studies which required handling or close proximity to bulk high explosives such as TNT, PETN, and RDX. The second manuscript reports the results of research in the design and application of canine training aids for non-traditional, peroxide-based explosives. Organic peroxides such as triacetonetriperoxide (TATP) and hexamethylenetriperoxidediamine (HMTD) can be synthesized relatively easily with store-bought ingredients and have become popular improvised explosives with many terrorist groups. Due to the hazards of handling such sensitive compounds, this research established methods for preparing training aids which contained safe quantities of TATP and HMTD for use in imprinting canines with their characteristic odor. Manuscripts 3 and 4 of this dissertation focus on research conducted to characterize pipe bombs during and after an explosion (post-blast). Pipe bombs represent a large percentage of domestic devices encountered by law enforcement. The current project has involved the preparation and controlled explosion of over 90 pipe bombs of different configurations in order to obtain data on fragmentation patterns, fragment velocity, blast overpressure, and fragmentation distance. Physical data recorded from the collected fragments, such as mass, size, and thickness, was correlated with the relative power of the initial device. Manuscript 4 explores the microstructural analysis of select pipe bomb fragments. Shock-loading of the pipe steel led to plastic deformation and work hardening in the steel grain structure as evidenced by optical microscopy and

  8. Soil Stabilisation Using Ground Granulated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Pathak

    2014-05-01

    Full Text Available Stabilisation is a broad sense for the various methods employed and modifying the properties of a soil to improve its engineering performance and used for a variety of engineering works. In today‟s day soil stabilisation is the major problem for civil engineers, either for construction of road and also for increasing the strength or stability of soil and reduces the construction cost. In this thesis the soil are stabilised by ground granulated blast furnace slag (GGBS and this material is obtained from the blast furnace of cement plant, which is the byproduct of iron (from ACC plant, sindri. It is generally obtained in three shaped one is air cooled, foamed shaped and another is in granulated shaped. The use of by-product materials for stabilisation has environmental and economic benefits. Ground granulated blast furnace slag (GGBS material is used in the current work to stabilise soil (clay. The main objectives of this research were to investigate the effect of GGBS on the engineering property (optimum moisture content and maximum dry density, plastic limit, liquid limit, compaction, unconfined compressive strength, triaxial and California bearing ratio test of the soil and determine the engineering properties of the stabilised.

  9. Self-similar relativistic blast waves with energy injection

    Science.gov (United States)

    van Eerten, Hendrik

    2014-08-01

    A sufficiently powerful astrophysical source with power-law luminosity in time will give rise to a self-similar relativistic blast wave with a reverse shock travelling into the ejecta and a forward shock moving into the surrounding medium. Once energy injection ceases and the last energy is delivered to the shock front, the blast wave will transit into another self-similar stage depending only on the total amount of energy injected. I describe the effect of limited duration energy injection into environments with density depending on radius as a power law, emphasizing optical/X-ray Gamma-ray Burst afterglows as applications. The blast wave during injection is treated analytically, the transition following last energy injection with one-dimensional simulations. Flux equations for synchrotron emission from the forward and reverse shock regions are provided. The reverse shock emission can easily dominate, especially with different magnetizations for both regions. Reverse shock emission is shown to support both the reported X-ray and optical correlations between afterglow plateau duration and end time flux, independently of the luminosity power-law slope. The model is demonstrated by application to bursts 120521A and 090515, and can accommodate their steep post-plateau light-curve slopes.

  10. Blast impact behaviour of concrete with different fibre reinforcement

    Directory of Open Access Journals (Sweden)

    Drdlová Martina

    2015-01-01

    Full Text Available The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concrete prism specimens have been subjected to the determination of mechanical parameters (compressive and flexural strength at quasi-static load. The blast tests were conducted on the slab specimens prepared from selected mixtures. The material characteristics and explosion test data have been used for numerical investigation, which defined the optimal wall composition and dimensions of the concrete element which should resist the explosion defined by type, size, weight and placement of the blast. In the next step the test elements resistance was verified by real explosion test.

  11. Partnering and the WCI blast furnace reline

    Energy Technology Data Exchange (ETDEWEB)

    Musolf, D.W. [WCI Steel, Inc., Warren, OH (United States)

    1997-11-01

    In 1993, WCI Steel entered into a partnership agreement to perform a blast furnace reline. The reline included a complete rebrick from the tuyere breast to the furnace top including the tapholes. Also included was the replacement of the Paul Wurth top equipment from the receiving hoppers through the gearbox and distribution chute, a skip incline replacement, and installation of tilting runners and a casthouse roof. The bustle pipe and hot blast main were repaired. One stove was also replaced. The reline was accomplished in 36 days, wind to wind, which allowed for 29 days of construction inside the blast furnace proper.

  12. Flyrock risk prevention in open pit blasting

    OpenAIRE

    Slopnicki, Jakub Patryk

    2013-01-01

    Norcem limestone quarry at Bjørntvedt has neighbours and infrastructure close to the quarry. Elimination of the risk of flyrock from blasting is thus of great importance to the operation. For drill hole dimension 3,5? ? as used at Bjørntvedt -the risk zone of flyrock is considered to be between 600 and 700 m from the blast. It is recommended to cover the blast if there are sensitive installations or people inside this radius. If no cover is used, adequate alternative preventive meas...

  13. Rice Blast Control and Polyvarietal Planting in the Philippines: A Study in Genotype by Environment Biogeography

    Directory of Open Access Journals (Sweden)

    Daniel J. Falvo

    2001-06-01

    Full Text Available Current approaches to biogeography are based on organismic biology. Certain biogeographical phenomena, however, cannot be fully understood using organismic approaches to biogeography. I employed an approach based on molecular biology and biochemistry that I call genotype by environment biogeography in order to provide a more complete understanding of why the dispersal of rice blast disease is less efficient in fields planted with mixtures of rice varieties. In a case study of an upland ricefield in the Philippines, I found that planting varietal mixtures results in a form of effective blast control that I call intrafield gene deployment. I suggest that intrafield gene deployment be used to design more effective methods of blast control in intensive rice agriculture.

  14. Macro-mechanical modelling of blast wave mitigation in foams. Part I: review of available experiments and models

    Science.gov (United States)

    Britan, A.; Shapiro, H.; Liverts, M.; Ben-Dor, G.; Chinnayya, A.; Hadjadj, A.

    2013-02-01

    Multiphase flows, which involve compressible or incompressible fluids with linear or nonlinear dynamics, are found in all areas of technology at all length scales and flow regimes. In this contribution, we discuss application of aqueous-foam barriers against blast wave impact. The first experiments demonstrating this behaviour were conducted in the early 1980s in free-field tests. Based on structural requirements, various foams with different blast energy contents were tested with the aim of characterizing the time history of the blast pressure reduction. A number of consistent methodologies for calculating this pressure reduction in foam are based on the effective gas flow model. For estimating the uncertainties of these methodologies, we briefly demonstrate their comparison with existing experimental data. Thereafter, we present various modifications of modelling approaches and their comparison with new results of blast wave experiments.

  15. A new non-uniform blast load model for SDOF method of one-way reinforced concrete slab

    Directory of Open Access Journals (Sweden)

    Wang S.-C.

    2012-08-01

    Full Text Available A new effective model for calculation of the equivalent uniform blast load for non-uniform blast load such as close-in explosion of a one-way square and rectangle reinforced concrete slab is proposed in this paper. The model is then validated using single degree of freedom (SDOF system with the experiments and blast tests for square slabs and rectangle slabs. Test results showed that the model is accurate in predicting the explosive charge weight and stand-off distance to impose a given damage level on the tested RC slabs especially for close-in blast load. It is shown that the new model is more accurate than the conventional SDOF analysis and is running faster than the FE analysis.

  16. Chronic caffeine exposure attenuates blast-induced memory deficit in mice

    Institute of Scientific and Technical Information of China (English)

    Ya-Lei Ning; Nan Yang; Xing Chen; Zi-Ai Zhao; Xiu-Zhu Zhang; Xing-Yun Chen; Ping Li

    2015-01-01

    Objective:To investigate the effects of three different ways of chronic caffeine administration on blastinduced memory dysfunction and to explore the underlying mechanisms.Methods:Adult male C57BL/6 mice were used and randomly divided into five groups:control:without blast exposure,con-water:administrated with water continuously before and after blast-induced traumatic brain injury (bTBI),con-caffeine:administrated with caffeine continuously for 1 month before and after bTBI,pre-caffeine:chronically administrated with caffeine for 1 month before bTBI and withdrawal after bTBI,post-caffeine:chronically administrated with caffeine after bTBI.After being subjected to moderate intensity of blast injury,mice were recorded for learning and memory performance using Morris water maze (MWM) paradigms at 1,4,and 8 weeks post-blast injury.Neurological deficit scoring,glutamate concentration,proinflammatory cytokines production,and neuropathological changes at 24 h,1,4,and 8 weeks post-bTBI were examined to evaluate the brain injury in early and prolonged stages.Adenosine A1 receptor expression was detected using qPCR.Results:All of the three ways of chronic caffeine exposure ameliorated blast-induced memory deficit,which is correlated with the neuroprotective effects against excitotoxicity,inflammation,astrogliosis and neuronal loss at different stages of injury.Continuous caffeine treatment played positive roles in both early and prolonged stages of bTBI;pre-bTBl and post-bTBl treatment of caffeine tended to exert neuroprotective effects at early and prolonged stages of bTBI respectively.Up-regulation of adenosine A1 receptor expression might contribute to the favorable effects of chronic caffeine consumption.Conclusion:Since caffeinated beverages are widely consumed in both civilian and military personnel and are convenient to get,the results may provide a promising prophylactic strategy for blast-induced neurotrauma and the consequent cognitive impairment.

  17. Gene interactions and genetics of blast resistance and yield attributes in rice (Oryza sativa L.).

    Science.gov (United States)

    Divya, B; Biswas, A; Robin, S; Rabindran, R; Joel, A John

    2014-08-01

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. The epistatic interaction model was found adequate to explain the gene action in most of the traits. The interaction was complementary for number of productive tillers, economic yield, lesion number, infected leaf area and potential disease incidence but duplicate epistasis was observed for the remaining traits. Among the genotypes tested under epiphytotic conditions, gene pyramided lines were highly resistant to blast compared to individuals with single genes indicating that the nonallelic genes have a complementary effect when present together. The information on genetics of various contributing traits of resistance will further aid plant breeders in choosing appropriate breeding strategy for blast resistance and yield enhancement in rice. PMID:25189236

  18. Nucleotide Base Variation of Blast Disease Resistance Gene Pi33 in Rice Selected Broad Genetic Background

    Directory of Open Access Journals (Sweden)

    DWINITA WIKAN UTAMI

    2011-09-01

    Full Text Available Rice is one of the most important crops for human beings, thus increasing productivity are continually persecuted. Blast disease can reduce the rate of productivity of rice cultivation. Therefore, the program of blast disease-resistant varieties needs to do effectively. One of broad-spectrum blast disease-resistant gene is Pi33. This study was aimed to identify the variation in the sequence of nucleotide bases of Pi33 gene in five interspesific lines which derived from Bio46 (IR64/Oryza rufipogon and CT13432 crossing. DNA of five rice lines were amplified using the spesific primer for Pi33, G1010. Amplification results purified through Exonuclease 1 and Shrimp Alkaline Phosphatase protocols. Labelling using fluorescent dyes done before sequencing nucleotide base using CEQ8000 instrument. The results showed that lines number 28 showed introgesion of the three control parent genome (subspecies of Indica, subspecies of Japonica, and O. rufipogon while the Lines number 79, 136, and 143 were identical to Indica genome. Strain number 195 was identical to Japonica genome. These broad genetic background lines promise as durable performance to attack the expansion of the dynamic nature of the pathogen to blast. The result of ortholog sequence analysis found conserved nucleotide base sequence (CAGCAGCC which involved in heterotrimeric G-protein group. This protein has role as plant receptor for recognizing pathogen elicitor in interaction of rice and blast pathogen.

  19. Waste plastics as supplemental fuel in the blast furnace process: improving combustion efficiencies.

    Science.gov (United States)

    Kim, Dongsu; Shin, Sunghye; Sohn, Seungman; Choi, Jinshik; Ban, Bongchan

    2002-10-14

    The possibility of using waste plastics as a source of secondary fuel in a blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. For instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in a blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with a decrease in particle size, the combustibility of waste polyethylene could be improved at a given distance from the tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at a longer distance from the tuyere. PMID:12220825

  20. NK cell-mediated killing of AML blasts. Role of histamine, monocytes and reactive oxygen metabolites

    International Nuclear Information System (INIS)

    Blasts recovered from patients with acute myelogenous leukaemia (AML) were lysed by heterologeous natural killer (NK) cells treated with NK cell-activating cytokine-induced killing of AML blasts was inhibited by monocytes, recovered from peripheral blood by counterflow centrifugal elutriation. Histamine, at concentrations exceeding 0.1 μM, abrogated the monocyte-induced inhibition of NK cells; thereby, histamine and IL-2 or histamine and IFN-α synergistically induced NK cell-mediated destruction of AML blasts. The effect of histamine was completely blocked by the histamine H2-receptor (H2R) antagonist ranitidine but not by its chemical control AH20399AA. Catalase, a scavenger of reactive oxygen metabolites (ROM), reversed the monocyte-induced inhibition of NK cell-mediated killing of blast cells, indicating that the inhibitory signal was mediated by products of the respiratory burst of monocytes. It is concluded that (i) monocytes inhibit anti-leukemic properties of NK cells, (ii) the inhibition is conveyed by monocyte-derived ROM, and (iii) histamine reverses the inhibitory signal and, thereby, synergizes with NK cell-activating cytokines to induce killing of AML blasts. (au) 19 refs

  1. A Feasibility Study for Recycling Used Automotive Oil Filters In A Blast Furnace; FINAL

    International Nuclear Information System (INIS)

    This feasibility study has indicated that of the approximately 120,000 tons of steel available to be recycled from used oil filters (UOF's), a maximum blast furnace charge of 2% of the burden may be anticipated for short term use of a few months. The oil contained in the most readily processed UOF's being properly hot drained and crushed is approximately 12% to 14% by weight. This oil will be pyrolized at a rate of 98% resulting in additional fuel gas of 68% and a condensable hydrocarbon fraction of 30%, with the remaining 2% resulting as carbon being added into the burden. Based upon the writer's collected information and assessment, there appears to be no operational problems relating to the recycling of UOF's to the blast furnace. One steel plant in the US has been routinely charging UOF's at about 100 tons to 200 tons per month for many years. Extensive analysis and calculations appear to indicate no toxic consideration as a result of the pyrolysis of the small contained oil ( in the 'prepared' UOFs) within the blast furnace. However, a hydrocarbon condensate in the ''gasoline'' fraction will condense in the blast furnace scrubber water and may require additional processing the water treatment system to remove benzene and toluene from the condensate. Used oil filters represent an additional source of high quality iron units that may be effectively added to the charge of a blast furnace for beneficial value to the operator and to the removal of this resource from landfills

  2. Gene interactions and genetics of blast resistance and yield attributes in rice (Oryza sativa L.)

    Indian Academy of Sciences (India)

    B. Divya; A. Biswas; S. Robin; R. Rabindran; A. John Joel

    2014-08-01

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. The epistatic interaction model was found adequate to explain the gene action in most of the traits. The interaction was complementary for number of productive tillers, economic yield, lesion number, infected leaf area and potential disease incidence but duplicate epistasis was observed for the remaining traits. Among the genotypes tested under epiphytotic conditions, gene pyramided lines were highly resistant to blast compared to individuals with single genes indicating that the nonallelic genes have a complementary effect when present together. The information on genetics of various contributing traits of resistance will further aid plant breeders in choosing appropriate breeding strategy for blast resistance and yield enhancement in rice.

  3. 城市复杂环境下场地平整控制爆破设计及实施%Design and Implement of Ground Leveling Control Blasting in Complex Urban Environment

    Institute of Scientific and Technical Information of China (English)

    李金铸; 吴立; 李波; 袁青

    2014-01-01

    为研究城市复杂环境下场地平整控制爆破相关理论及实践,以某场地平整土石方爆破为工程背景,设计了采用浅孔台阶爆破、二次爆破及桩孔爆破相结合的控制爆破设计方案。通过对爆破施工现场进行多次试爆,设计了该复杂环境下的控制爆破参数。采用TC-4850爆破测振仪对爆破地震波作用下的岩土体振动进行跟踪监测,对实测峰值合振速通过最小二乘法展开回归分析,得到该场地的爆破地震波衰减规律,爆破过程取得了安全高效的施工效果。%In order to study the theory and practice of ground leveling control blasting in complex urban environ-ment,a shallow rock blasting scheme was performed. The controlled blasting scheme was designed with shallow bench blasting,secondary blasting and pile blasting methods. The control blasting parameters were designed in complicated environment through blasting construction site test. The TC-4850 blasting vibration was used to track and monitor the vibration of rock under the action of blast seismic waves. The measured peak velocity was analyzed through least square method and the blasting seismic wave attenuation rule of the field was obtained. Finally,the safe and effective blasting effects were obtained.

  4. 3-D reconstruction and analysis of X-ray micro-CT images by using VoxBlast software. The effect of raloxifene on the lumbar vertebrae in ovariectomized mice

    International Nuclear Information System (INIS)

    To evaluate the skeletal efficacy of raloxifene on the osteoporosis in ovariectomized mice model, the sixth lumbar vertebrae was scanned by X-ray micro-CT, and these resulting 8-bit gray-scale images were analyzed by using commercial three-dimensional (3-D) reconstruction software (VoxBlastTM Mac, VayTek, Inc., USA). In this paper, it is described how to use VoxBlast software practically for processing sequential datasets from CT scanners. Furthermore, we demonstrate in 3-D visualization that new trabecular bones build compact bridge constructions in the lumbar vertebrae after the treatment with raloxifene. (author)

  5. BLAST-EXPLORER helps you building datasets for phylogenetic analysis

    Directory of Open Access Journals (Sweden)

    Claverie Jean-Michel

    2010-01-01

    Full Text Available Abstract Background The right sampling of homologous sequences for phylogenetic or molecular evolution analyses is a crucial step, the quality of which can have a significant impact on the final interpretation of the study. There is no single way for constructing datasets suitable for phylogenetic analysis, because this task intimately depends on the scientific question we want to address, Moreover, database mining softwares such as BLAST which are routinely used for searching homologous sequences are not specifically optimized for this task. Results To fill this gap, we designed BLAST-Explorer, an original and friendly web-based application that combines a BLAST search with a suite of tools that allows interactive, phylogenetic-oriented exploration of the BLAST results and flexible selection of homologous sequences among the BLAST hits. Once the selection of the BLAST hits is done using BLAST-Explorer, the corresponding sequence can be imported locally for external analysis or passed to the phylogenetic tree reconstruction pipelines available on the Phylogeny.fr platform. Conclusions BLAST-Explorer provides a simple, intuitive and interactive graphical representation of the BLAST results and allows selection and retrieving of the BLAST hit sequences based a wide range of criterions. Although BLAST-Explorer primarily aims at helping the construction of sequence datasets for further phylogenetic study, it can also be used as a standard BLAST server with enriched output. BLAST-Explorer is available at http://www.phylogeny.fr

  6. Basic Local Alignment Search Tool (BLAST)

    Data.gov (United States)

    U.S. Department of Health & Human Services — BLAST finds regions of similarity between biological sequences. The program compares nucleotide or protein sequences to sequence databases and calculates the...

  7. Silica Brick for Hot Blast Stove

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 1 Scope This standard specifies the glossary and definition, marking, shape and dimension, technical requirements, test method, quality appraisal procedure, packing, label, transportation, storage and quality certification of silica brick for hot blast stove.

  8. Anhydrous Taphole Mix for Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan

    2010-01-01

    @@ 1 Scope This standard specifies the term,definition,brand,label,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of anhydrous taphole mix for blast furnace.

  9. Kaolinite Refractory Bricks for Blast Furnaces

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ This standard is suitable to the fireclay bricks for blast furnace. 1 Classification, Shape and Dimension 1 According to physical and chemical indexes, the brick can be divided into two trademarks: ZGN-42 and GN-42.

  10. BLAST FURNACE GRANULAR COAL INJECTION SYSTEM; FINAL

    International Nuclear Information System (INIS)

    Bethlehem Steel Corporation (BSC) requested financial assistance from the Department of Energy (DOE), for the design, construction and operation of a 2,800-ton-per-day blast furnace granulated coal injection (BFGCI) system for two existing iron-making blast furnaces. The blast furnaces are located at BSC's facilities in Burns Harbor, Indiana. The demonstration project proposal was selected by the DOE and awarded to Bethlehem in November 1990. The design of the project was completed in December 1993 and construction was completed in January 1995. The equipment startup period continued to November 1995 at which time the operating and testing program began. The blast furnace test program with different injected coals was completed in December 1998

  11. Disruption of caudate working memory activation in chronic blast-related traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Mary R. Newsome

    2015-01-01

    Full Text Available Mild to moderate traumatic brain injury (TBI due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes. Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate. Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results

  12. Detecting Residues On Grit-Blasted Surfaces

    Science.gov (United States)

    Novak, H. L.; Zook, L. M.

    1989-01-01

    Addition of fluorescent or iridescent material to plastic grit particles proposed for detection of grit residues after grit-blast cleaning. Residual films visible by observing grit-blasted surfaces under infrared or ultraviolet light. Plastic grit contains fluorescent or iridescent additive in core and coating. Wherever grit material becomes embedded, additive makes it visible under infrared or ultraviolet light. Applicable to other grit materials, for example fluorescent or iridescent materials added to particles of glass, silicon carbide, aluminum oxide, or zirconium silicate.

  13. The use of blast furnace slag

    OpenAIRE

    Václavík, Vojtěch; Dirner, Vojtech; Dvorský, Tomáš; Daxner, J.

    2012-01-01

    The paper presents the results of experimental research that dealt with the substitution of fi nely ground blast furnace slag for Portland cement in the course of simple concrete manufacturing. Physical and mechanical properties of experimental concrete mixtures based on fi nely ground blast furnace slag were observed. Rad predstavlja rezultate eksperimentalnog istraživanja koja se bave mogućnostima primjene fi nozrnate troske iz visoke peći za Portland cement u jednostavnoj proiz...

  14. Fabrication of microstructures by powder blasting

    OpenAIRE

    Wensink, Hendrik

    2002-01-01

    This thesis deals with the use of powder blasting as a micromachining technique to create micro systems. Powder blasting is a technology in which small particles, accelerated by an air jet, are directed towards a brittle target for mechanical material removal. It is especially useful for glass machining due to the limitations of other glass micromachining techniques. Particle jets have been used for many years to test the wear resistance of materials. Chapter 2 gives a literature overview of ...

  15. Coals characterization for blast furnace tuyeres injection

    International Nuclear Information System (INIS)

    The efficiency of blast furnace operation with pulverized coal injection (PCI) by tuyeres is determined by the composition and properties of the used coals and by the quality of the ferrous burden and coke. A study in thermo balance of coals to be injected by tuyeres is carried out, and the softening and melting temperatures of coals ash are determined. The coal performance and its influence in the blast furnace operation is estimated. (Author) 7 refs

  16. Energy spectrum analysis of blast waves based on an improved Hilbert-Huang transform

    Science.gov (United States)

    Li, L.; Wang, F.; Shang, F.; Jia, Y.; Zhao, C.; Kong, D.

    2016-07-01

    Using the improved Hilbert-Huang transform (HHT), this paper investigates the problems of analysis and interpretation of the energy spectrum of a blast wave. It has been previously established that the energy spectrum is an effective feature by which to characterize a blast wave. In fact, the higher the energy spectra in a frequency band of a blast wave, the greater the damage to a target in the same frequency band. However, most current research focuses on analyzing wave signals in the time domain or frequency domain rather than considering the energy spectrum. We propose here an improved HHT method combined with a wavelet packet to extract the energy spectrum feature of a blast wave. When applying the HHT, the signal is first roughly decomposed into a series of intrinsic mode functions (IMFs) by empirical mode decomposition. The wavelet packet method is then performed on each IMF to eliminate noise on the energy spectrum. Second, a coefficient is introduced to remove unrelated IMFs. The energy of each instantaneous frequency can be derived through the Hilbert transform. The energy spectrum can then be obtained by adding up all the components after the wavelet packet filters and screens them through a coefficient to obtain the effective IMFs. The effectiveness of the proposed method is demonstrated by 12 groups of experimental data, and an energy attenuation model is established based on the experimental data. The improved HHT is a precise method for blast wave signal analysis. For other shock wave signals from blasting experiments, an energy frequency time distribution and energy spectrum can also be obtained through this method, allowing for more practical applications.

  17. Information modeling system for blast furnace control

    Science.gov (United States)

    Spirin, N. A.; Gileva, L. Y.; Lavrov, V. V.

    2016-09-01

    Modern Iron & Steel Works as a rule are equipped with powerful distributed control systems (DCS) and databases. Implementation of DSC system solves the problem of storage, control, protection, entry, editing and retrieving of information as well as generation of required reporting data. The most advanced and promising approach is to use decision support information technologies based on a complex of mathematical models. The model decision support system for control of blast furnace smelting is designed and operated. The basis of the model system is a complex of mathematical models created using the principle of natural mathematical modeling. This principle provides for construction of mathematical models of two levels. The first level model is a basic state model which makes it possible to assess the vector of system parameters using field data and blast furnace operation results. It is also used to calculate the adjustment (adaptation) coefficients of the predictive block of the system. The second-level model is a predictive model designed to assess the design parameters of the blast furnace process when there are changes in melting conditions relative to its current state. Tasks for which software is developed are described. Characteristics of the main subsystems of the blast furnace process as an object of modeling and control - thermal state of the furnace, blast, gas dynamic and slag conditions of blast furnace smelting - are presented.

  18. An Abridged Review of Blast Wave Parameters

    Directory of Open Access Journals (Sweden)

    Manmohan Dass Goel

    2012-09-01

    Full Text Available In case of blast loading on structures, analysis is carried out in two stages, first the blast loading on a particular structure is determined and second, an evaluation is made for the response of the structure to this loading. In this paper, a review of the first part is presented which includes various empirical relations available for computation of blast load in the form of pressure-time function resulting from the explosion in the air. Different empirical techniques available in the form of charts and equations are reviewed first and then the various blast wave parameters are computed using these equations. This paper is providing various blast computation equations, charts, and references in a concise form at a single place and to serve as base for researchers and designers to understand, compare, and then compute the blast wave parameters. Recommendations are presented to choose the best suitable technique from the available methods to compute the pressure-time function for obtaining structural response.Defence Science Journal, 2012, 62(5, pp.300-306, DOI:http://dx.doi.org/10.14429/dsj.62.1149

  19. Underwater blast injury: a review of standards.

    Science.gov (United States)

    Lance, Rachel M; Bass, Cameron R

    2015-09-01

    The first cases of underwater blast injury appeared in the scientific literature in 1917, and thousands of service members and civilians were injured or killed by underwater blast during WWII. The prevalence of underwater blast injuries and occupational blasting needs led to the development of many safety standards to prevent injury or death. Most of these standards were not supported by experimental data or testing. In this review, we describe existing standards, discuss their origins, and we comprehensively compare their prescriptions across standards. Surprisingly, we found that most safety standards had little or no scientific basis, and prescriptions across standards often varied by at least an order of magnitude. Many published standards traced back to a US Navy 500 psi guideline, which was intended to provide a peak pressure at which injuries were likely to occur. This standard itself seems to have been based upon a completely unfounded assertion that has propagated throughout the literature in subsequent years. Based on the limitations of the standards discussed, we outline future directions for underwater blast injury research, such as the compilation of epidemiological data to examine actual injury risk by human beings subjected to underwater blasts. PMID:26415071

  20. Blast Load Input Estimation of the Medium Girder Bridgeusing Inverse Method

    Directory of Open Access Journals (Sweden)

    Ming-Hui Lee

    2008-01-01

    Full Text Available Innovative adaptive weighted input estimation inverse methodology for estimating theunknown time-varying blast loads on the truss structure system is presented. This method isbased on the Kalman filter and the recursive least square estimator (RLSE. The filter models thesystem dynamics in a linear set of state equations. The state equations of the truss structureare constructed using the finite element method. The input blast loads of the truss structuresystem are inverse estimated from the system responses measured at two distinct nodes. Thiswork presents an efficient weighting factor  applied in the RLSE, which is capable of providinga reasonable estimation results. The results obtained from the simulations show that the methodis effective in estimating input blast loads, so has great stability and precision.Defence Science Journal, 2008, 58(1, pp.46-56, DOI:http://dx.doi.org/10.14429/dsj.58.1622

  1. Blast furnace granular coal injection at Bethlehem Steel's Burns Harbor Plant

    Energy Technology Data Exchange (ETDEWEB)

    D. Gregory Hill; Leo I.E. Makovsky; Thomas A. Sarkus; Howard G. McIlvried [Bethlehem Steel Corporation, Chesterton, IN (USA)

    2004-03-01

    The paper discusses the demonstration of the British Steel/CPC-Macawber Blast Furnace Granular Coal Injection (BFGCI) technology that was installed on the blast furnaces at Bethlehem Steel's Burns Harbor Plant in Indiana as a highly successful Clean Coal Technology project, cofunded by the U.S. Department of Energy. In the BFGCI process, granular coal (10%-30% through a 200-mesh screen) is injected into a blast furnace as a fuel supplement to decrease coke requirements, thus reducing costs. Tests run to determine the effect of process variables on furnace operations showed that granular coal works as well as pulverized coal and is easier to handle and cheaper to produce because of reduced grinding costs.

  2. An Investigation of The Reticulated Foam - Perforated Steel Sheet Sandwich Structure As A Blast Mitigation Media

    Science.gov (United States)

    Nguyen, Thuy-Tien Ngoc; Proud, William; Institute of Shock Physics, Imperial College London Collaboration; Royal British Legion CentreBlast Injury Studies at Imperial College London Collaboration

    2015-06-01

    Explosions have always been the main cause of injuries during battles and conflicts, with improvised explosive devices (IEDs) becoming more and more common nowadays. In this paper, the interaction between blast waves and sandwich structures of reticulated foam and perforated sheets, with varying thickness and configuration, is studied using an air-driven shock tube apparatus. The mitigation effects for primary blast injuries of these structures are discussed in terms of pulse shape, pressure magnitude as well as shock impulse. Schlieren photography together with other high-speed imaging was also used to visually investigate the matter. The results show that lower open area of perforated sheet and increased thickness of foam offer best protection. However, below a threshold thickness, no mitigation is seen. The Institute of Shock Physics acknowledges the support of AWE, Aldermaston, UK and Imperial College London. The Centre for Blast Injury Studies acknowledges the support of the Royal British Legion and Imperial College London.

  3. Skull flexure from blast waves: a mechanism for brain injury with implications for helmet design

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2009-04-14

    Traumatic brain injury [TBI] has become a signature injury of current military conflicts. The debilitating effects of TBI are long-lasting and costly. Although the mechanisms by which impacts cause TBI have been well researched, the mechanisms by which blasts cause TBI are not understood. Various possibilities have been investigated, but blast-induced deformation of the skull has been neglected. From numerical hydrodynamic simulations, we have discovered that nonlethal blasts can induce sufficient flexure of the skull to generate potentially damaging loads in the brain, even if no impact occurs. The possibility that this mechanism may contribute to TBI has implications for the diagnosis of soldiers and the design of protective equipment such as helmets.

  4. Abrasive blast cleaning method for the renewal of worn-out acceleration tubes

    International Nuclear Information System (INIS)

    The degradation of the electrical properties of acceleration tubes emerging with performance time is known to be assigned mainly to impurities and surface breakdown tracks appearing on the inner surface of the insulators. Consequently, a radical treatment for removing the surface layer may result in a renewal of the tube. An abrasive blast cleaning procedure has been used on a set of worn-out acceleration tube units. The cleaned tube exhibited its original electrical characteristics and it has been used for more than 4000 h of operation up to the maximum rated voltage of our 5 MV electrostatic accelerator without any observable degradation. XRF and PIXE analytical measurements performed on used and blast-treated insulators as well as on electrode and pump oil samples reveal the contribution of elementary processes in the acceleration tube to the ageing of the tube and indicate the effectness of the blasting process used for the re-establishment of clean surface conditions. (orig.)

  5. Design and commissioning of a semi-confined blast chamber

    Institute of Scientific and Technical Information of China (English)

    I.M. SNYMAN; F.J. MOSTERT; W. GRUNDLING

    2016-01-01

    This paper presents the design, test and analysis of a scaled cylindrical blast chamber. The blast chamber is a one-fifth dimensional size replica of the full-scale blast chamber (Emily). The blast chamber is semi-confined as one end is open. The scaled blast chamber is used to test concepts for closing the open end and allows the gas to vent at the same time. ANSYS AUTODYN calculated the pressure time histories for different closure scenarios. Comparing the results suggested a viable scenario, namely a structure consisting of a circular disc and a frame positioned at the open end of the blast chamber. The structure and cylindrical blast chamber were subjected to scaled blast tests and the pressure results are presented and discussed.

  6. Comparison of Some Blast Vibration Predictors for Blasting in Underground Drifts and Some Observations

    Science.gov (United States)

    Bhagwat, Vaibhab Pramod; Dey, Kaushik

    2016-04-01

    Drilling and blasting are the most economical excavation techniques in underground drifts driven through hard rock formation. Burn cut is the most popular drill pattern, used in this case, to achieve longer advance per blast round. The ground vibration generated due to the propagation of blast waves on the detonation of explosive during blasting is the principal cause for structural and rock damage. Thus, ground vibration is a point of concern for the blasting engineers. The ground vibration from a blast is measured using a seismograph placed at the blast monitoring station. The measured vibrations, in terms of peak particle velocity, are related to the maximum charge detonated at one instant and the distance of seismograph from the blast point. The ground vibrations from a number of blast rounds of varying charge/delay and distances are monitored. A number of scaling factors of these dependencies (viz. Distance and maximum charge/delay) have been proposed by different researchers, namely, square root, cube root, CMRI, Langefors and Kihlstrom, Ghosh-Daemon, Indian standard etc. Scaling factors of desired type are computed for all the measured blast rounds. Regression analysis is carried out between the scaling factors and peak particle velocities to establish the coefficients of the vibration predictor equation. Then, the developed predictor equation is used for designing the blast henceforth. Director General of Mine Safety, India, specified that ground vibrations from eight to ten blast rounds of varying charge/delay and distances should be monitored to develop a predictor equation; however, there is no guideline about the type of scaling factor to be used. Further to this, from the statistical point of view, a regression analysis on a small sample population cannot be accepted without the testing of hypothesis. To show the importance of the above, in this paper, seven scaling factors are considered for blast data set of a hard-rock underground drift using burn

  7. A Blast Shock Isolation System with MRFD and Its Semi-Active Control Analysis

    Institute of Scientific and Technical Information of China (English)

    LIU Jingbo; WANG Libin; DU Yixin; WANG Yan

    2006-01-01

    To effectively reduce the damage to people and devices in civil defense engineering subjected to blast shock,a blast shock isolation system with magnetorheological fluid dampers (MRFD) is proposed.MRFD can provide continuously adjustable Coulomb friction and has many advantages for semi-active control.Numerical simulation of this isolation system is finished using Matlab simulink toolbox.General semi-active control algorithms are consided based on instantaneous optimal active control algorithm.And the results indicate that the shock isolation system can work efficiently,decreasing about 93% of the peak acceleration of the isolation floor.

  8. Skull Flexure from Blast Waves: A Mechanism for Brain Injury with Implications for Helmet Design

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2009-04-30

    Traumatic brain injury [TBI] has become a signature injury of current military conflicts, with debilitating, costly, and long-lasting effects. Although mechanisms by which head impacts cause TBI have been well-researched, the mechanisms by which blasts cause TBI are not understood. From numerical hydrodynamic simulations, we have discovered that non-lethal blasts can induce sufficient skull flexure to generate potentially damaging loads in the brain, even without a head impact. The possibility that this mechanism may contribute to TBI has implications for injury diagnosis and armor design.

  9. Brain Response to Primary Blast Wave Using Validated Finite Element Models of Human Head and Advanced Combat Helmet

    Science.gov (United States)

    Zhang, Liying; Makwana, Rahul; Sharma, Sumit

    2013-01-01

    Blast-induced traumatic brain injury has emerged as a “signature injury” in combat casualty care. Present combat helmets are designed primarily to protect against ballistic and blunt impacts, but the current issue with helmets is protection concerning blasts. In order to delineate the blast wave attenuating capability of the Advanced Combat Helmet (ACH), a finite element (FE) study was undertaken to evaluate the head response against blast loadings with and without helmet using a partially validated FE model of the human head and ACH. Four levels of overpressures (0.27–0.66 MPa) from the Bowen’s lung iso-damage threshold curves were used to simulate blast insults. Effectiveness of the helmet with respect to head orientation was also investigated. The resulting biomechanical responses of the brain to blast threats were compared for human head with and without the helmet. For all Bowen’s cases, the peak intracranial pressures (ICP) in the head ranged from 0.68 to 1.8 MPa in the coup cortical region. ACH was found to mitigate ICP in the head by 10–35%. Helmeted head resulted in 30% lower average peak brain strains and product of strain and strain rate. Among three blast loading directions with ACH, highest reduction in peak ICP (44%) was due to backward blasts whereas the lowest reduction in peak ICP and brain strains was due to forward blast (27%). The biomechanical responses of a human head to primary blast insult exhibited directional sensitivity owing to the different geometry contours and coverage of the helmet construction and asymmetric anatomy of the head. Thus, direction-specific tolerances are needed in helmet design in order to offer omni-directional protection for the human head. The blasts of varying peak overpressures and durations that are believed to produce the same level of lung injury produce different levels of mechanical responses in the brain, and hence “iso-damage” curves for brain injury are likely different than the Bowen

  10. Cygnus Loop Supernova Blast Wave

    Science.gov (United States)

    1993-01-01

    This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to

  11. Methodology of Testing Shot Blasting Machines in Industrial Conditions

    OpenAIRE

    R. Wrona; P. Zyzak; E. Ziółkowski; M. Brzeziński

    2012-01-01

    Shot blasting machines are widely used for automated surface treatment and finishing of castings. In shot blasting processes the stream of shots is generated and shaped by blasting turbines, making up a kinetic and dynamic system comprising a separating rotor, an adapting sleeve and a propelling rotor provided with blades. The shot blasting performance- i.e. the quality of shot treated surfaces depends on the actual design and operational parameters of the unit whilst the values of relevant p...

  12. Cloning of novel rice blast resistance genes from two rapidly evolving NBS-LRR gene families in rice.

    Science.gov (United States)

    Guo, Changjiang; Sun, Xiaoguang; Chen, Xiao; Yang, Sihai; Li, Jing; Wang, Long; Zhang, Xiaohui

    2016-01-01

    Most rice blast resistance genes (R-genes) encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. Our previous study has shown that more rice blast R-genes can be cloned in rapidly evolving NBS-LRR gene families. In the present study, two rapidly evolving R-gene families in rice were selected for cloning a subset of genes from their paralogs in three resistant rice lines. A total of eight functional blast R-genes were identified among nine NBS-LRR genes, and some of these showed resistance to three or more blast strains. Evolutionary analysis indicated that high nucleotide diversity of coding regions served as important parameters in the determination of gene resistance. We also observed that amino-acid variants (nonsynonymous mutations, insertions, or deletions) in essential motifs of the NBS domain contribute to the blast resistance capacity of NBS-LRR genes. These results suggested that the NBS regions might also play an important role in resistance specificity determination. On the other hand, different splicing patterns of introns were commonly observed in R-genes. The results of the present study contribute to improving the effectiveness of R-gene identification by using evolutionary analysis method and acquisition of novel blast resistance genes.

  13. The complexity of biomechanics causing primary blast-induced traumatic brain injury: a review of potential mechanisms.

    Directory of Open Access Journals (Sweden)

    Amy eCourtney

    2015-10-01

    Full Text Available Primary blast induced traumatic brain injury (bTBI is a prevalent battlefield injury in recent conflicts, yet biomechanical mechanisms of bTBI remain unclear. Elucidating specific biomechanical mechanisms is essential to developing animal models for testing candidate therapies and for improving protective equipment. Three hypothetical mechanisms of primary bTBI have received the most attention. Because translational and rotational head accelerations are primary contributors to TBI from non-penetrating blunt force head trauma, the acceleration hypothesis suggests that blast-induced head accelerations may cause bTBI. The hypothesis of direct cranial transmission suggests that a pressure transient traverses the skull into the brain and directly injures brain tissue. The thoracic hypothesis of bTBI suggests that some combination of a pressure transient reaching the brain via the thorax and a vagally mediated reflex result in bTBI. These three mechanisms may not be mutually exclusive, and quantifying exposure thresholds (for blasts of a given duration is essential for determining which mechanisms may be contributing for a level of blast exposure. Progress has been hindered by experimental designs which do not effectively expose animal models to a single mechanism and by over-reliance on poorly validated computational models. The path forward should be predictive validation of computational models by quantitative confirmation with blast experiments in animal models, human cadavers, and biofidelic human surrogates over a range of relevant blast magnitudes and durations coupled with experimental designs which isolate a single injury mechanism.

  14. The development of a rat model to investigate the formation of blast-related post-traumatic heterotopic ossification.

    Science.gov (United States)

    Polfer, E M; Hope, D N; Elster, E A; Qureshi, A T; Davis, T A; Golden, D; Potter, B K; Forsberg, J A

    2015-04-01

    Currently, there is no animal model in which to evaluate the underlying physiological processes leading to the heterotopic ossification (HO) which forms in most combat-related and blast wounds. We sought to reproduce the ossification that forms under these circumstances in a rat by emulating patterns of injury seen in patients with severe injuries resulting from blasts. We investigated whether exposure to blast overpressure increased the prevalence of HO after transfemoral amputation performed within the zone of injury. We exposed rats to a blast overpressure alone (BOP-CTL), crush injury and femoral fracture followed by amputation through the zone of injury (AMP-CTL) or a combination of these (BOP-AMP). The presence of HO was evaluated using radiographs, micro-CT and histology. HO developed in none of nine BOP-CTL, six of nine AMP-CTL, and in all 20 BOP-AMP rats. Exposure to blast overpressure increased the prevalence of HO. This model may thus be used to elucidate cellular and molecular pathways of HO, the effect of varying intensities of blast overpressure, and to evaluate new means of prophylaxis and treatment of heterotopic ossification. PMID:25820900

  15. Race Specificity of Major Rice Blast Resistance Genes to Magnaporthe grisea Isolates Collected from indica Rice in Guangdong, China

    Institute of Scientific and Technical Information of China (English)

    YANG Jian-yuan; CHEN Shen; ZENG Lie-xian; LI Yi-long; CHEN Zhen; LI Chuan-ying; ZHO Xiao-yuan

    2008-01-01

    Race-specific resistance and field resistance of 30 rice blast resistance monogenic lines dedved from different resources were evaluated. The spectra of resistance to 163 Magnaporthe grisea isolates collected from indica rice in Guangdong Province, China ranged from 0.6% to 89.6%. Most of the monogenic lines showed a narrow resistance spectrum and high susceptibility in rice blast area, whereas the lines with Pikh and Pi1(t) had the broad resistance spectra of 89.6% and 82.2% respectively, showing a high and stable blast resistance in fields. According to the cluster analysis of specific resistance to 163 blast isolates tested, the 30 monogenic lines were divided into 15 groups, and based on the principal factor analysis, nine kinds of race-specific resistance were identified. Pik, Piz5, Pi9 and Pish can be used as candidate resistance genes for rice breeding since their specific resistance differed from those of the backbone parents in Guangdong, China. Gene pyramiding of Pikh [or Pi1(t)], Pi9 (or Piz5) and Pish (or Pita2) will be effective to obtain broad-spectrum blast resistance in rice breeding program in Guangdong, China. The strategies for studying and application of rice blast resistance genes were discussed.

  16. CFD modeling of multiphase reacting flow in blast furnace shaft with layered burden

    International Nuclear Information System (INIS)

    The ironmaking blast furnace is a counter-current chemical reactor which includes the ascending gas flow and the counter-current descending porous bed (burden). A Computational Fluid Dynamics (CFD) model has been developed to simulate the multiphase reacting flow in blast furnace shaft. The gas flow dynamics, burden movement, chemical reactions, heat and mass transfer between the gas phase and burden phase are included in the CFD model. The blast furnace burden consists of alternative layers of iron ore and coke. A novel methodology is proposed to efficiently model the effects of alternative burden layer structure on gas flow, heat transfer, mass transfer and chemical reactions. Different reactions and heat transfer characteristics are applied for difference types of layer. In addition, the layered CFD model accurately predicts the Cohesive Zone (CZ) shape where the melting of solid burden taking place. The shape and location of the CZ are determined by an iterative method based on the ore temperature distribution. The theoretical formation and the methodology of the CFD model are presented and the model is applied to simulate industry blast furnaces. The proposed method can be applied to investigate the blast furnace shaft process and other moving bed system with periodic burden structure configuration. - Highlights: •A novel methodology is proposed to efficiently model the blast furnace shaft with layered burden. •The effects of layered burden on flow, heat transfer, and chemical reactions are considered in the model. •The shape and location of the cohesive zone is determined by an iterative method

  17. Alkahest NuclearBLAST : a user-friendly BLAST management and analysis system

    Directory of Open Access Journals (Sweden)

    Burke Mark

    2005-06-01

    Full Text Available Abstract Background - Sequencing of EST and BAC end datasets is no longer limited to large research groups. Drops in per-base pricing have made high throughput sequencing accessible to individual investigators. However, there are few options available which provide a free and user-friendly solution to the BLAST result storage and data mining needs of biologists. Results - Here we describe NuclearBLAST, a batch BLAST analysis, storage and management system designed for the biologist. It is a wrapper for NCBI BLAST which provides a user-friendly web interface which includes a request wizard and the ability to view and mine the results. All BLAST results are stored in a MySQL database which allows for more advanced data-mining through supplied command-line utilities or direct database access. NuclearBLAST can be installed on a single machine or clustered amongst a number of machines to improve analysis throughput. NuclearBLAST provides a platform which eases data-mining of multiple BLAST results. With the supplied scripts, the program can export data into a spreadsheet-friendly format, automatically assign Gene Ontology terms to sequences and provide bi-directional best hits between two datasets. Users with SQL experience can use the database to ask even more complex questions and extract any subset of data they require. Conclusion - This tool provides a user-friendly interface for requesting, viewing and mining of BLAST results which makes the management and data-mining of large sets of BLAST analyses tractable to biologists.

  18. 30 CFR 75.1316 - Preparation before blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Preparation before blasting. 75.1316 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1316 Preparation before blasting. (a)(1) All nonbattery-powered electric equipment, including cables, located within...

  19. 30 CFR 57.22607 - Blasting on shift (III mines).

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting on shift (III mines). 57.22607 Section... Standards for Methane in Metal and Nonmetal Mines Explosives § 57.22607 Blasting on shift (III mines). When blasting on shift, tests for methane shall be made in the mine atmosphere by a competent person...

  20. 30 CFR 75.1310 - Explosives and blasting equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and blasting equipment. 75.1310... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only permissible explosives, approved sheathed explosive units,...

  1. 30 CFR 57.6306 - Loading, blasting, and security.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Loading, blasting, and security. 57.6306... Transportation-Surface and Underground § 57.6306 Loading, blasting, and security. (a) When explosive materials or... blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of...

  2. 30 CFR 56.6300 - Control of blasting operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of blasting operations. 56.6300 Section... § 56.6300 Control of blasting operations. (a) Only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and related activities. (b) Trainees...

  3. 30 CFR 57.6605 - Isolation of blasting circuits.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Isolation of blasting circuits. 57.6605 Section... Extraneous Electricity-Surface and Underground § 57.6605 Isolation of blasting circuits. Lead wires and blasting lines shall be isolated and insulated from power conductors, pipelines, and railroad tracks,...

  4. 30 CFR 816.64 - Use of explosives: Blasting schedule.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Use of explosives: Blasting schedule. 816.64... ACTIVITIES § 816.64 Use of explosives: Blasting schedule. (a) General requirements. (1) The operator shall conduct blasting operations at times approved by the regulatory authority and announced in the...

  5. 30 CFR 57.6300 - Control of blasting operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of blasting operations. 57.6300 Section... Transportation-Surface and Underground § 57.6300 Control of blasting operations. (a) Only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and...

  6. BLAST Autonomous Daytime Star Cameras

    CERN Document Server

    Rex, M; Devlin, M J; Gundersen, J; Klein, J; Pascale, E; Wiebe, D; Rex, Marie; Chapin, Edward; Devlin, Mark J.; Gundersen, Joshua; Klein, Jeff; Pascale, Enzo; Wiebe, Donald

    2006-01-01

    We have developed two redundant daytime star cameras to provide the fine pointing solution for the balloon-borne submillimeter telescope, BLAST. The cameras are capable of providing a reconstructed pointing solution with an absolute accuracy < 5 arcseconds. They are sensitive to stars down to magnitudes ~ 9 in daytime float conditions. Each camera combines a 1 megapixel CCD with a 200 mm f/2 lens to image a 2 degree x 2.5 degree field of the sky. The instruments are autonomous. An internal computer controls the temperature, adjusts the focus, and determines a real-time pointing solution at 1 Hz. The mechanical details and flight performance of these instruments are presented.

  7. Neuro-Glial and Systemic Mechanisms of Pathological Responses in Rat Models of Primary Blast Overpressure Compared to “Composite” Blast

    OpenAIRE

    Svetlov, Stanislav I.; Prima, Victor; Glushakova, Olena; Svetlov, Artem; Kirk, Daniel R.; Gutierrez, Hector; Serebruany, Victor L.; Curley, Kenneth C.; Wang, Kevin K. W.; Hayes, Ronald L.

    2012-01-01

    A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position toward blast generated by an external shock tube. In this study, we further characterized blast producing moderate traumatic brain injury and defined “composite” blast and ...

  8. Microrobotized blasting improves the bone-to-textured implant response. A preclinical in vivo biomechanical study.

    Science.gov (United States)

    Coelho, Paulo G; Gil, Luiz F; Neiva, Rodrigo; Jimbo, Ryo; Tovar, Nick; Lilin, Thomas; Bonfante, Estevam A

    2016-03-01

    This study evaluated the effect of microrobotized blasting of titanium endosteal implants relative to their manually blasted counterparts. Two different implant systems were utilized presenting two different implant surfaces. Control surfaces (Manual) were fabricated by manually grit blasting the implant surfaces while experimental surfaces (Microblasted) were fabricated through a microrobotized system that provided a one pass grit blasting routine. Both surfaces were created with the same ~50µm average particle size alumina powder at ~310KPa. Surfaces were then etched with 37% HCl for 20min, washed, and packaged through standard industry procedures. The surfaces were characterized through scanning electron microscopy (SEM) and optical interferometry, and were then placed in a beagle dog radius model remaining in vivo for 3 and 6 weeks. The implant removal torque was recorded and statistical analysis evaluated implant system and surface type torque levels as a function of time in vivo. Histologic sections were qualitatively evaluated for tissue response. Electron microscopy depicted textured surfaces for both manual and microblasted surfaces. Optical interferometry showed significantly higher Sa, Sq, values for the microblasted surface and no significant difference for Sds and Sdr values between surfaces. In vivo results depicted that statistically significant gains in biomechanical fixation were obtained for both implant systems tested at 6 weeks in vivo, while only one system presented significant biomechanical gain at 3 weeks. Histologic sections showed qualitative higher amounts of new bone forming around microblasted implants relative to the manually blasted group. Microrobotized blasting resulted in higher biomechanical fixation of endosteal dental implants and should be considered as an alternative for impant surface manufacturing. PMID:26703231

  9. Release of elicitors from rice blast spores under the action of reactive oxygen species

    Science.gov (United States)

    The effects of reactive oxygen species (ROS) on secretion of hypothesized elicitors from spores of rice blast causal fungus Magnaporthe grisea were studied. For spore exposure to exogenous ROS, they were germinated for 5 h in 50 µM H2O2 followed by addition of catalase E.C. 1.11.1.6 (to decompose pe...

  10. Detecting Sequence Homology at the Gene Cluster Level with MultiGeneBlast

    NARCIS (Netherlands)

    Medema, Marnix H.; Takano, Eriko; Breitling, Rainer; Nowick, Katja

    2013-01-01

    The genes encoding many biomolecular systems and pathways are genomically organized in operons or gene clusters. With MultiGeneBlast, we provide a user-friendly and effective tool to perform homology searches with operons or gene clusters as basic units, instead of single genes. The contextualizatio

  11. Statistical inference of selection and divergence of rice blast resistance gene Pi-ta

    Science.gov (United States)

    The resistance gene Pi-ta has been effectively used to control rice blast disease worldwide. A few recent studies have described the possible evolution of Pi-ta in cultivated and weedy rice. However, evolutionary statistics used for the studies are too limited to precisely understand selection and d...

  12. Modeling of a self-healing process in blast furnace slag cement exposed to accelerated carbonation

    NARCIS (Netherlands)

    Zemskov, S.V.; Ahmad, B.; Copuroglu, O.; Vermolen, F.J.

    2013-01-01

    In the current research, a mathematical model for the post-damage improvement of the carbonated blast furnace slag cement (BFSC) exposed to accelerated carbonation is constructed. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, whi

  13. Effect of Portable Vacuum Sealing Drainage Device in Blast Inj ury Wounds Drainage%便携式封闭负压引流装置对家猪爆炸伤模型创面的引流效果

    Institute of Scientific and Technical Information of China (English)

    杏玲芝; 张华; 王东红; 焦耿军; 王云

    2014-01-01

    目的:评估自制的便携式封闭负压引流(vacuum sealing drainage,VSD)装置对家猪爆炸伤模型创面的引流效果。方法遴选市售健康5~6个月龄家猪4头,雌雄各半,体质量35~40 kg,将雷管植入双侧后肢肌肉组织发达处,制造8个爆炸创面,配对分成观察组和对照组。在室外暴露创面4 h后进行清创,观察组给予彻底清创,VSD装置处理;对照组彻底清创后,无菌纱布覆盖。分别于暴露创面4h,治疗3、7d后对伤口大体判断疗效,观察白细胞、表皮生长因子的变化。结果爆炸4h后,两组实验对象白细胞、表皮生长因子的变化差异无统计学意义(P>0.05);治疗3、7 d后,观察组白细胞、表皮生长因子明显高于对照组,差异有统计学意义(P<0.05)。观察组伤口大体判断疗效观察较对照组创面清洁、无异味,触之易出血,创面有大量的颗粒状肉芽组织,创面周缘无明显的水肿和继发性坏死组织。结论自制便携式封闭负压引流装置在家猪爆炸创面愈合方面效果显著,且装置体积小、携带方便,可进一步应用于临床护理实践验证。%Objective To evaluate the effect of new patent of self-made portable vacuum sealing drainage device in animal experiment blast inj ury wounds drainage.Methods 4 pigs with two male and two female, body weight 35~40 kg were selected and implant the detonator in the developed muscle tissue of hind limbs,and made 8 blast inj ury wound,and paring into observation group and control group.The wounds were exposed outdoor and debride the wounds after 4 h.The observation group was given thorough debridement with VSD treatment;the control group was treated with sterile gauze covered after thorough debridement.The wounds healing situation and the change of white blood cells,epidermal growth factor were observed respectively at 4h after wounds exposed,3d and 7d after treatment

  14. FastBLAST: homology relationships for millions of proteins.

    Directory of Open Access Journals (Sweden)

    Morgan N Price

    Full Text Available BACKGROUND: All-versus-all BLAST, which searches for homologous pairs of sequences in a database of proteins, is used to identify potential orthologs, to find new protein families, and to provide rapid access to these homology relationships. As DNA sequencing accelerates and data sets grow, all-versus-all BLAST has become computationally demanding. METHODOLOGY/PRINCIPAL FINDINGS: We present FastBLAST, a heuristic replacement for all-versus-all BLAST that relies on alignments of proteins to known families, obtained from tools such as PSI-BLAST and HMMer. FastBLAST avoids most of the work of all-versus-all BLAST by taking advantage of these alignments and by clustering similar sequences. FastBLAST runs in two stages: the first stage identifies additional families and aligns them, and the second stage quickly identifies the homologs of a query sequence, based on the alignments of the families, before generating pairwise alignments. On 6.53 million proteins from the non-redundant Genbank database ("NR", FastBLAST identifies new families 25 times faster than all-versus-all BLAST. Once the first stage is completed, FastBLAST identifies homologs for the average query in less than 5 seconds (8.6 times faster than BLAST and gives nearly identical results. For hits above 70 bits, FastBLAST identifies 98% of the top 3,250 hits per query. CONCLUSIONS/SIGNIFICANCE: FastBLAST enables research groups that do not have supercomputers to analyze large protein sequence data sets. FastBLAST is open source software and is available at http://microbesonline.org/fastblast.

  15. Numerical Simulation of Rock Mass Damage Evolution During Deep-Buried Tunnel Excavation by Drill and Blast

    Science.gov (United States)

    Yang, Jianhua; Lu, Wenbo; Hu, Yingguo; Chen, Ming; Yan, Peng

    2015-09-01

    Presence of an excavation damage zone (EDZ) around a tunnel perimeter is of significant concern with regard to safety, stability, costs and overall performance of the tunnel. For deep-buried tunnel excavation by drill and blast, it is generally accepted that a combination of effects of stress redistribution and blasting is mainly responsible for development of the EDZ. However, few open literatures can be found to use numerical methods to investigate the behavior of rock damage induced by the combined effects, and it is still far from full understanding how, when and to what degree the blasting affects the behavior of the EDZ during excavation. By implementing a statistical damage evolution law based on stress criterion into the commercial software LS-DYNA through its user-subroutines, this paper presents a 3D numerical simulation of the rock damage evolution of a deep-buried tunnel excavation, with a special emphasis on the combined effects of the stress redistribution of surrounding rock masses and the blasting-induced damage. Influence of repeated blast loadings on the damage extension for practical millisecond delay blasting is investigated in the present analysis. Accompanying explosive detonation and secession of rock fragments from their initial locations, in situ stress in the immediate vicinity of the excavation face is suddenly released. The transient characteristics of the in situ stress release and induced dynamic responses in the surrounding rock masses are also highlighted. From the simulation results, some instructive conclusions are drawn with respect to the rock damage mechanism and evolution during deep-buried tunnel excavation by drill and blast.

  16. Simulation Assisted Risk Assessment: Blast Overpressure Modeling

    Science.gov (United States)

    Lawrence, Scott L.; Gee, Ken; Mathias, Donovan; Olsen, Michael

    2006-01-01

    A probabilistic risk assessment (PRA) approach has been developed and applied to the risk analysis of capsule abort during ascent. The PRA is used to assist in the identification of modeling and simulation applications that can significantly impact the understanding of crew risk during this potentially dangerous maneuver. The PRA approach is also being used to identify the appropriate level of fidelity for the modeling of those critical failure modes. The Apollo launch escape system (LES) was chosen as a test problem for application of this approach. Failure modes that have been modeled and/or simulated to date include explosive overpressure-based failure, explosive fragment-based failure, land landing failures (range limits exceeded either near launch or Mode III trajectories ending on the African continent), capsule-booster re-contact during separation, and failure due to plume-induced instability. These failure modes have been investigated using analysis tools in a variety of technical disciplines at various levels of fidelity. The current paper focuses on the development and application of a blast overpressure model for the prediction of structural failure due to overpressure, including the application of high-fidelity analysis to predict near-field and headwinds effects.

  17. Acid slag injection into the blast furnace tuyere zone

    Energy Technology Data Exchange (ETDEWEB)

    Haerkki, J.; Tervola, K. [Oulu Univ. (Finland). Dept. of Process Engineering

    1996-12-31

    The possibility of acid slag injection and its effect on the slag formation and on the melting behaviour of the charge materials are studied in the present work. The work is partly based on the literature evaluating the slag formation, slag properties and the basic slag injection. The possibility of acid slag injection is first examined by studying changes in the composition of the primary slag if the share of the acid slag component (Kostamus pellet/RR) of the charge material is lowered. Phase diagrams and viscosity charts are used to evaluate the viscosity, and solidus/liquidus temperature in the slag phase. The share of the slag phase of the pellet is evaluated by calculating the amount of the acid slag injection. The injection rate of some injectants is also examined. The primary slag formed of the sinter and the coke ash is in liquid form and its viscosity is close to the viscosity of the blast furnace slag. It is possible that the liquid slag phase can be formed in the blast furnace without the presence of the acid pellet because the melting point and the viscosity of the slag is lowered by alkalies, sulfur and the dissolved ironoxide of the slag. If high SiO{sub 2} content materials alone are used for injection there is a risk that the slag phase of the tuyere zone becomes too viscous. Olivine and some iron containing components such as fayalite are possible injection material. More information is needed to evaluate the effect of acid slag injection on the operation of the blast furnace. (orig.) SULA 2 Research Programme; 2 refs.

  18. Attachment and proliferation of human oral fibroblasts to titanium surfaces blasted with TiO2 particles. A scanning electron microscopic and histomorphometric analysis.

    Science.gov (United States)

    Mustafa, K; Silva Lopez, B; Hultenby, K; Wennerberg, A; Arvidson, K

    1998-06-01

    The purpose of this study was to determine the effect of c.p. titanium surfaces blasted with TiO2 particles on the biological responses of human gingival fibroblasts (HGF). Fibroblast morphology and attachment were investigated on turned (control) titanium surfaces and those blasted with 45 microns (standard), 45-63 microns, and 63-90 microns TiO2 particles. The specimens were analyzed using a confocal laser scanner and SEM. The cell profile areas were measured using a semiautomatic interactive image analyser. The figures were expressed as percent of attachment. The turned samples had the smoothest surfaces and the roughest were those blasted with 63-90 microns. All TiO2 blasted specimens had homogeneous surfaces. Cells appeared to flatten, spread and form cellular bridges with the adjacent cells. Fibroblasts on the turned titanium surfaces appeared to follow the direction of the fine irregularities on the surface but tended to spread haphazardly on the blasted surfaces. The attachment assays showed no significant difference in the percentage of fibroblast cell attachment on the standard surfaces compared to the turned surfaces. Both surfaces blasted with 45-63 microns or 63-90 microns had significantly (P texture influences the attachment and growth of HGF: surfaces blasted with 45 microns TiO2 do not inhibit fibroblast attachment and smooth or finely grooved surfaces could be conducive to cellular attachment. PMID:10530134

  19. Surface modification with alumina blasting and H2SO4-HCl etching for bonding two resin-composite veneers to titanium.

    Science.gov (United States)

    Taira, Yohsuke; Egoshi, Takafumi; Kamada, Kohji; Sawase, Takashi

    2014-02-01

    The purpose of this study was to investigate the effect of an experimental surface treatment with alumina blasting and acid etching on the bond strengths between each of two resin composites and commercially pure titanium. The titanium surface was blasted with alumina and then etched with 45wt% H2SO4 and 15wt% HCl (H2SO4-HCl). A light- and heat-curing resin composite (Estenia) and a light-curing resin composite (Ceramage) were used with adjunctive metal primers. Veneered specimens were subjected to thermal cycling between 4 and 60°C for 50,000 cycles, and the shear bond strengths were determined. The highest bond strengths were obtained for Blasting/H2SO4-HCl/Estenia (30.2 ± 4.5 MPa) and Blasting/Etching/Ceramage (26.0 ± 4.5 MPa), the values of which were not statistically different, followed by Blasting/No etching/Estenia (20.4 ± 2.4 MPa) and Blasting/No etching/Ceramage (0.8 ± 0.3 MPa). Scanning electron microscopy observations revealed that alumina blasting and H2SO4-HCl etching creates a number of micro- and nanoscale cavities on the titanium surface, which contribute to adhesive bonding.

  20. Stochastic Modeling Approach for the Evaluation of Backbreak due to Blasting Operations in Open Pit Mines

    Science.gov (United States)

    Sari, Mehmet; Ghasemi, Ebrahim; Ataei, Mohammad

    2014-03-01

    Backbreak is an undesirable side effect of bench blasting operations in open pit mines. A large number of parameters affect backbreak, including controllable parameters (such as blast design parameters and explosive characteristics) and uncontrollable parameters (such as rock and discontinuities properties). The complexity of the backbreak phenomenon and the uncertainty in terms of the impact of various parameters makes its prediction very difficult. The aim of this paper is to determine the suitability of the stochastic modeling approach for the prediction of backbreak and to assess the influence of controllable parameters on the phenomenon. To achieve this, a database containing actual measured backbreak occurrences and the major effective controllable parameters on backbreak (i.e., burden, spacing, stemming length, powder factor, and geometric stiffness ratio) was created from 175 blasting events in the Sungun copper mine, Iran. From this database, first, a new site-specific empirical equation for predicting backbreak was developed using multiple regression analysis. Then, the backbreak phenomenon was simulated by the Monte Carlo (MC) method. The results reveal that stochastic modeling is a good means of modeling and evaluating the effects of the variability of blasting parameters on backbreak. Thus, the developed model is suitable for practical use in the Sungun copper mine. Finally, a sensitivity analysis showed that stemming length is the most important parameter in controlling backbreak.