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Sensitivity (explosives)
In explosives engineering, sensitivity refers to the degree to which an explosive can be initiated by impact, heat, or friction. Current in-use standard methods of mechanical (impact and friction) senstivity determination differ by the sample preparation (constant mass or volume is usually used; pile or pressed pellet), sample arrangement (confined/unconfined sample etc), instrument type, go/not go criteria, and the statistical analysis of results. Sensitivity, stability and brisance are three of the most significant properties of explosives that affect their use and application. All explosive compounds have a certain amount of energy required to initiate. If an explosive is too sensitive, it may go off accidentally. A safer explosive is less sensitive and will not explode if accidentally dropped or mishandled. However, such explosives are more difficult to initiate intentionally. Explosive train Less sensitive explosives can be initiated by smaller quantities of more sensitiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosives Engineering
Explosives engineering is the field of science and engineering which is related to examining the behavior and usage of explosive materials. Topics Some of the topics that explosives engineers study, research, and work on include: * Development and characterization of new explosive materials in various forms * Analysis of the physical process of detonation * Explosive generated shock waves and their effects on materials * Safety testing of explosives * Analysis and engineering of rock blasting for mining * Design and analysis of shaped charges and reactive armor * Design and analysis of military explosives such as shells, aerial bombs, missile warheads, etc. * Bomb disposal *Drilling and Blasting *Explosive Manufacturing *Explosives Safety Education and Certification *Drilling Safety Education and Certification *Blasting Safety Education and Certification Organizations Listed in Alphabetical Order: * Explosives Academy * International Society of Explosives Engineers (I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Materials
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or BLEVE * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock (mechanics)
A mechanical or physical shock is a sudden acceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation. Shock describes matter subject to extreme rates of force with respect to time. Shock is a vector that has units of an acceleration (rate of change of velocity). The unit ''g'' (or g) represents multiples of the acceleration of gravity and is conventionally used. A shock pulse can be characterised by its peak acceleration, the duration, and the shape of the shock pulse (half sine, triangular, trapezoidal, etc.). The shock response spectrum is a method for further evaluating a mechanical shock. Shock measurement Shock measurement is of interest in several fields such as *Propagation of heel shock through a runner's body *Measure the magnitude of a shock need to cause damage to an item: fragility. *Measure shock attenuation through athletic flooring *Measuring the effectiveness of a shock absorber *Measuring the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or BLEVE * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Expl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Explosives
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or BLEVE * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firing Train
Dismissal (also called firing) is the termination of employment by an employer against the will of the employee. Though such a decision can be made by an employer for a variety of reasons, ranging from an economic downturn to performance-related problems on the part of the employee, being fired has a strong stigma in some cultures. To be dismissed, as opposed to quitting voluntarily (or being laid off), is often perceived as being the employee's fault. Finding new employment may often be difficult after being fired, particularly if there is a history of being terminated from a previous job, if the reason for firing is for some serious infraction, or the employee did not keep the job very long. Job seekers will often not mention jobs that they were fired from on their resumes; accordingly, unexplained gaps in employment are often regarded as a red flag. Usage While the main formal term for ending someone's employment is "dismissal", there are a number of colloquial or euphemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initiation Sequence
Initiation is a rite of passage marking entrance or acceptance into a group or society. It could also be a formal admission to adulthood in a community or one of its formal components. In an extended sense, it can also signify a transformation in which the initiate is 'reborn' into a new role. Examples of initiation ceremonies might include Christian baptism or confirmation, Jewish bar or bat mitzvah, acceptance into a fraternal organization, secret society or religious order, or graduation from school or recruit training. A person taking the initiation ceremony in traditional rites, such as those depicted in these pictures, is called an ''initiate''. See also rite of passage. Characteristics William Ian Miller notes the role of ritual humiliation in comic ordering and testing. Mircea Eliade discussed initiation as a principal religious act by classical or traditional societies. He defined initiation as "a basic change in existential condition", which liberates man from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Train
A triggering sequence, also called an explosive train or a firing train, is a sequence of events that culminates in the detonation of explosives. For safety reasons, most widely used high explosives are difficult to detonate. A primary explosive of higher sensitivity is used to trigger a uniform and predictable detonation of the main body of the explosive. Although the primary explosive itself is generally a more sensitive and expensive compound, it is only used in small quantities and in relatively safely packaged forms. By design there are low explosives and high explosives made such that the low explosives are highly sensitive (i.e. their Figure of Insensitivity is low) and high explosives are comparatively insensitive. This not only affords inherent safety to the usage of explosives during handling and transport, but also necessitates an explosive triggering sequence or explosive train. The explosive triggering sequence or the explosive train essentially consists of an 'initia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Reaction
A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that systems which are not in thermodynamic equilibrium can release energy or increase entropy in order to reach a state of higher entropy. For example, a system may not be able to reach a lower energy state by releasing energy into the environment, because it is hindered or prevented in some way from taking the path that will result in the energy release. If a reaction results in a small energy release making way for more energy releases in an expanding chain, then the system will typically collapse explosively until much or all of the stored energy has been released. A macroscopic metaphor for chain reactions is thus a snowball causing a larger snowball until finally an avalanche results (" snowball effect"). This is a result of stored gravitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blasting Cap
A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electrical detonators or the capped fuse which is a length of safety fuse to which an ordinary detonator has been joined. Many detonators' primary explosive is a material called ASA compound. This compound is formed from lead azide, lead styphnate and aluminium and is pressed into place above the base charge, usually TNT or tetryl in military detonators and PETN in commercial detonators. Other materials such as DDNP (diazo dinitro phenol) are also used as the primary charge to reduce the amount of lead emitted into the atmosphere by mining and quarrying operations. Old detonators used mercury fulminate as the primary, often mixed with potassium chlorate to yield better performance. A blasting cap is a small sensitive primary explosive devi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material, which may either be composed solely of one ingredient or be a mixture containing at least two substances. The potential energy stored in an explosive material may, for example, be * chemical energy, such as nitroglycerin or grain dust * pressurized gas, such as a gas cylinder, aerosol can, or BLEVE * nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239 Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detonator
A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electrical detonators or the capped fuse which is a length of safety fuse to which an ordinary detonator has been joined. Many detonators' primary explosive is a material called ASA compound. This compound is formed from lead azide, lead styphnate and aluminium and is pressed into place above the base charge, usually TNT or tetryl in military detonators and PETN in commercial detonators. Other materials such as DDNP (diazo dinitro phenol) are also used as the primary charge to reduce the amount of lead emitted into the atmosphere by mining and quarrying operations. Old detonators used mercury fulminate as the primary, often mixed with potassium chlorate to yield better performance. A blasting cap is a small sensitive primary explosive dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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