International Conference on Multimedia Information Networking and Security 

About: International Conference on Multimedia Information Networking and Security is an academic conference. The conference publishes majorly in the area(s): Ground-penetrating radar & Radar. Over the lifetime, 5268 publications have been published by the conference receiving 32589 citations.

Structure response and damage produced by ground vibration from surface mine blasting.

Abstract: Direct measurements were made of ground-vibration-produced structure responses and damage in 76 homes for 219 production blasts. These results were combined with damage data from nine other blasting studies, including the three analyzed previously for Bureau of Mines Bulletin 656. Safe levels of ground vibration from blasting range from 0.5 to 2.0 in/sec peak particle velocity for residential-type structures. The damage threshold values are functions of the frequencies of the vibration transmitted into the residences and the types of construction. Particularly serious are the low-frequency vibrations that exist in soft foundation materials and/or result from long blast-to-residence distances. These vibrations produce not only structure resonances but also excessive levels of displacement and strain. Threshold damage was defined as the occurrence of cosmetic damage; that is, the most superficial interior cracking of the type that develops in all homes independent of blasting. Homes with plastered interior walls are more susceptible to blast-produced cracking than gypsum wallboard. Structure response amplification factors were measured. Typical values were 1.5 for structures as a whole (racking) and 4 for midwalls, at their respective resonance frequencies. For blast vibrations above 40 Hz, all amplification factors for frame residential structures were less than unity. The human responsemore » and annoyance problem from ground vibration is aggravated by wall rattling, secondary noises, and the presence of airblast. Approximately 5 to 10% of the neighbors will judge peak particle velocity levels of 0.5 to 0.75 in/sec as less than acceptable (i.e., unacceptable) based on direct reactions to the vibration. Even lower levels cause psychological response problems, and thus social, economic, and public relations factors become critical for continued blasting.« less

A quoi tient le succès des innovations ? 1 : L'art de l'intéressement; 2 : Le choix des porte-parole

Abstract: Les ressorts de l'intrigue sont connus. D'un cote l'invention, c'est-a-dire les idees, les projets, les plans mais aussi les prototypes et les usines pilotes : en un mot tout ce qui precede la premiere et incertaine rencontre avec le client et le jugement qu'il rendra. De l'autre cote, l'innovation proprement dite, c'est-a-dire la premiere transaction commerciale reussie ou plus generalement la sanction positive de l'utilisateur. Entre les deux, un destin qui se joue selon un scenario mysterieux. Des firmes qui periclitent ou au contraire prosperent, des nations qui declinent ou, a l'inverse, deviennent hegemoniques. Un projet juge prometteur par tous les specialistes et qui s'effondre soudainement tandis qu'un autre, auquel personne ne croyait plus, se transforme brusquement en succes commercial. Et toujours les memes questions. Comment expliquer ces succes et ces echecs imprevisibles ? Comment rendre compte de ces retournements inattendus, de ces resistances qui se transforment en adhesion ou de ces enthousiasmes qui se muent en scepticisme puis en rejet ?

On the Nature of Reservoir-induced Seismicity

Abstract: In most cases of reservoir-induced seismicity, seismicity follows the impoundment, large lake-level changes, or filling at a later time above the highest water level achieved until then. We classify this as initial seismicity. This “initial seismicity” is ascribable to the coupled poroelastic response of the reservoir to initial filling or water level changes. It is characterized by an increase in seismicity above preimpoundment levels, large event(s), general stabilization and (usually) a lack of seismicity beneath the deepest part of the reservoir, widespread seismicity on the periphery, migrating outwards in one or more directions. With time, there is a decrease in both the number and magnitudes of earthquakes, with the seismicity returning to preimpoundment levels. However, after several years some reservoirs continue to be active; whereas, there is no seismicity at others. Preliminary results of two-dimensional (similar to those by Roeloffs, 1988) calculations suggest that, this “protracted seismicity” depends on the frequency and amplitude of lake-level changes, reservoir dimensions and hydromechanical properties of the substratum. Strength changes show delays with respect to lake-level changes. Longer period water level changes (~ 1 year) are more likely to cause deeper and larger earthquakes than short period water level changes. Earthquakes occur at reservoirs where the lake-level changes are comparable or a large fraction of the least depth of water. The seismicity is likely to be more widespread and deeper for a larger reservoir than for a smaller one. The induced seismicity is observed both beneath the deepest part of the reservoir and in the surrounding areas. The location of the seismicity is governed by the nature of faulting below and near the reservoir.

Theoretical Energy Release of Thermites, Intermetallics, and Combustible Metals

Abstract: Thermite mixtures, intermetallic reactants, and metal fuels have long been used in pyrotechnic applications. Advantages of these systems typically include high energy density, high combustion temperature, and a wide range of gas production. They generally exhibit high temperature stability and possess insensitive ignition properties. For the specific applications of humanitarian demining and disposal of unexploded ordnance, these pyrotechnic formulations offer additional benefits. The combination of high thermal input with low brisance can be used to neutralize the energetic materials in mines and other ordnance without the "explosive" high-blast-pressure events that can cause extensive collateral damage to personnel, facilities, and the environment. In this paper, we review the applications, benefits, and characteristics of thermite mixtures, intermetallic reactants, and metal fuels. Calculated values for reactant density, heat of reaction (per unit mass and per unit volume), and reaction temperature (without and with consideration of phase changes and the variation of specific heat values) are tabulated. These data are ranked in several ways, according to density, heat of reaction, reaction temperature, and gas production.