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70-504: The CRV7 was an offshoot of late 1950s research at CARDE (now DRDC Valcartier) into high-performance solid fuel rockets, research performed as a part of a general program studying anti-ballistic missiles . With Aerojet 's assistance, CARDE and Bristol developed the "Propulsion Test Vehicle" to test new fuel and engine designs. This program led to the development of the Black Brant sounding rocket , which first flew in 1960 and has had

140-420: A chemically pure compound, such as nitroglycerin , or a mixture of a fuel and an oxidizer , such as black powder or grain dust and air. Some chemical compounds are unstable in that, when shocked, they react, possibly to the point of detonation. Each molecule of the compound dissociates into two or more new molecules (generally gases) with the release of energy. The above compositions may describe most of

210-634: A degree of water resistance. Explosives based on ammonium nitrate have little or no water resistance as ammonium nitrate is highly soluble in water and is hygroscopic. Many explosives are toxic to some extent. Manufacturing inputs can also be organic compounds or hazardous materials that require special handling due to risks (such as carcinogens ). The decomposition products, residual solids, or gases of some explosives can be toxic, whereas others are harmless, such as carbon dioxide and water. Examples of harmful by-products are: "Green explosives" seek to reduce environment and health impacts. An example of such

280-477: A distance of 10,000 feet (3,000 m). It was also found to be a useful warhead for use against medium and light armoured vehicles. Further development led to the WDU-500X/B "General Purpose Flechette" which releases 80 tungsten flechettes that can penetrate 1.5 inches (38 mm) of roll-hardened armor for use against personnel, some light armour, thin-skinned vehicles, and helicopters. Bristol also re-sells

350-564: A long and successful career since then. Engineer Jose Tharayil from Bristol Aerospace is considered the driving force behind the CRV7's development and production. In the early 1970s, CARDE and Bristol decided to use the same propellant and engine design for a new 2.75-inch rocket to equip the Canadair CF-104 Starfighter . The resulting RLU-5001/B (C-14) engine was first delivered by Bristol in production form in 1973. It had

420-455: A new version of the CRV7, the CRV7-PG . The weapon was introduced at Eurosatory 2006. Bristol's current owners, Magellan Aerospace , offered it for sale starting in 2007. The PG version, for "precision guided", adds a seeker developed by Kongsberg Defence & Aerospace to the front of any version of an otherwise unmodified CRV7. The seeker uses a simple inertial guidance system through

490-433: A number of more exotic explosive materials, and exotic methods of causing explosions. Examples include nuclear explosives , and abruptly heating a substance to a plasma state with a high-intensity laser or electric arc . Laser- and arc-heating are used in laser detonators, exploding-bridgewire detonators , and exploding foil initiators , where a shock wave and then detonation in conventional chemical explosive material

560-739: A nylon fairing, and later introduced a similar version with a hardened steel rod, the WTU-5001A/B. These rounds matched the ballistics of the M151 for training purposes and were widely used during the development and introduction of the weapon to the Canadian Forces. Bristol followed this with the 16 lb (7.3 kg) WDU-50001/B "Anti-Bunkerette" round, a semi-armor-piercing high-explosive incendiary (SAPHEI/HEISAP) warhead designed for use against reinforced concrete buildings, specifically hardened aircraft shelters. Its heavy steel shell allows

630-685: A practical measure, primary explosives are sufficiently sensitive that they can be reliably initiated with a blow from a hammer; however, PETN can also usually be initiated in this manner, so this is only a very broad guideline. Additionally, several compounds, such as nitrogen triiodide , are so sensitive that they cannot even be handled without detonating. Nitrogen triiodide is so sensitive that it can be reliably detonated by exposure to alpha radiation . Primary explosives are often used in detonators or to trigger larger charges of less sensitive secondary explosives . Primary explosives are commonly used in blasting caps and percussion caps to translate

700-494: A re-alignment from pure research to smaller projects directly requested by the Armed Forces took place, along with a change of name to Defence Research Establishment Valcartier ( DREV ) and a general downsizing of the station and its budgets. Since then DREV has undertaken numerous projects in the field of battlefield command and control, detection and monitoring, and various battlefield decoy systems. On April 1, 2000, DREV

770-399: A reaction to be classified as a detonation as opposed to just a deflagration, the propagation of the reaction shockwave through the material being tested must be faster than the speed of sound through that material. The speed of sound through a liquid or solid material is usually orders of magnitude faster than the speed of sound through air or other gases. Traditional explosives mechanics

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840-735: A smaller number are manufactured specifically for the purpose of being used as explosives. The remainder are too dangerous, sensitive, toxic, expensive, unstable, or prone to decomposition or degradation over short time spans. In contrast, some materials are merely combustible or flammable if they burn without exploding. The distinction, however, is not very clear. Certain materials—dusts, powders, gases, or volatile organic liquids—may be simply combustible or flammable under ordinary conditions, but become explosive in specific situations or forms, such as dispersed airborne clouds , or confinement or sudden release . Early thermal weapons , such as Greek fire , have existed since ancient times. At its roots,

910-506: A tail-mounted igniter that was ejected by the rocket when it was fired. In some cases the igniter would hit the aircraft, causing minor damage. To address this, the RLU-5002A/B (HEPI) was introduced, with a "Head-End Permanent Igniter" that is not ejected on launch. The latest C-17 and C-18 engines for helicopter use offer somewhat lower impulse at 1,905 lbf·s (8.5 kN·s), but with almost no smoke at all. The primary warhead for

980-478: A test vehicle that would later become the Black Brant sounding rocket . Due to this research CARDE was later involved in the design of a US-Canada-Mexico meteorological sounding rocket, the Metroc . The ABM research eventually wound down with no working system in place, however the solid fuels developed during the program were widely used for rocketry in various western military systems. CARDE then looked into using

1050-618: A thermodynamically favorable process in addition to one that propagates very rapidly. Thus, explosives are substances that contain a large amount of energy stored in chemical bonds . The energetic stability of the gaseous products and hence their generation comes from the formation of strongly bonded species like carbon monoxide, carbon dioxide, and nitrogen gas, which contain strong double and triple bonds having bond strengths of nearly 1 MJ/mole. Consequently, most commercial explosives are organic compounds containing –NO 2 , –ONO 2 and –NHNO 2 groups that, when detonated, release gases like

1120-427: A total impulse of 2,320 lbf·s (10.3 kN·s) and a burn time of 2.2 seconds. The empty weight of the rocket is 6.6 kg, and it is normally equipped with a 10 lb (4.5 kg) high-explosive warhead taken from U.S. rockets. Compared to the U.S. Mk 40 FFAR Mighty Mouse rockets the CRV7 replaced, the higher energy fuel and newer fuselage design led to a longer and much flatter trajectory, with twice

1190-709: Is mining . Whether the mine is on the surface or is buried underground, the detonation or deflagration of either a high or low explosive in a confined space can be used to liberate a fairly specific sub-volume of a brittle material (rock) in a much larger volume of the same or similar material. The mining industry tends to use nitrate-based explosives such as emulsions of fuel oil and ammonium nitrate solutions, mixtures of ammonium nitrate prills (fertilizer pellets) and fuel oil ( ANFO ) and gelatinous suspensions or slurries of ammonium nitrate and combustible fuels. In materials science and engineering, explosives are used in cladding ( explosion welding ). A thin plate of some material

1260-427: Is a pure substance ( molecule ) that in a chemical reaction can contribute some atoms of one or more oxidizing elements, in which the fuel component of the explosive burns. On the simplest level, the oxidizer may itself be an oxidizing element , such as gaseous or liquid oxygen . The availability and cost of explosives are determined by the availability of the raw materials and the cost, complexity, and safety of

1330-402: Is an important consideration in selecting an explosive for a particular purpose. The explosive in an armor-piercing projectile must be relatively insensitive, or the shock of impact would cause it to detonate before it penetrated to the point desired. The explosive lenses around nuclear charges are also designed to be highly insensitive, to minimize the risk of accidental detonation. The index of

1400-440: Is an important element influencing the yield of the energy transmitted for both atmospheric over-pressure and ground acceleration. By definition, a "low explosive", such as black powder, or smokeless gunpowder has a burn rate of 171–631 m/s. In contrast, a "high explosive", whether a primary, such as detonating cord , or a secondary, such as TNT or C-4, has a significantly higher burn rate about 6900–8092 m/s. Stability

1470-520: Is based on the shock-sensitive rapid oxidation of carbon and hydrogen to carbon dioxide, carbon monoxide and water in the form of steam. Nitrates typically provide the required oxygen to burn the carbon and hydrogen fuel. High explosives tend to have the oxygen, carbon and hydrogen contained in one organic molecule, and less sensitive explosives like ANFO are combinations of fuel (carbon and hydrogen fuel oil) and ammonium nitrate . A sensitizer such as powdered aluminum may be added to an explosive to increase

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1540-443: Is created by laser- or electric-arc heating. Laser and electric energy are not currently used in practice to generate most of the required energy, but only to initiate reactions. To determine the suitability of an explosive substance for a particular use, its physical properties must first be known. The usefulness of an explosive can only be appreciated when the properties and the factors affecting them are fully understood. Some of

1610-452: Is evaluated by a tailored series of tests to assess the material for its intended use. Of the tests listed below, cylinder expansion and air-blast tests are common to most testing programs, and the others support specific applications. In addition to strength, explosives display a second characteristic, which is their shattering effect or brisance (from the French meaning to "break"). Brisance

1680-430: Is imparted by small fins at the rear of the rocket body that flip out into the airstream once the rocket leaves its launch tube. The fins take a short time to open and more time to start the rocket spinning. During this period, the rockets can drift significantly from their original aim point. The CRV7 solved this problem by adding small vanes projecting into the rocket exhaust to start the rocket spinning even before it left

1750-472: Is important in determining the effectiveness of an explosion in fragmenting shells, bomb casings, and grenades . The rapidity with which an explosive reaches its peak pressure ( power ) is a measure of its brisance. Brisance values are primarily employed in France and Russia. The sand crush test is commonly employed to determine the relative brisance in comparison to TNT. No test is capable of directly comparing

1820-400: Is placed atop a thick layer of a different material, both layers typically of metal. Atop the thin layer is placed an explosive. At one end of the layer of explosive, the explosion is initiated. The two metallic layers are forced together at high speed and with great force. The explosion spreads from the initiation site throughout the explosive. Ideally, this produces a metallurgical bond between

1890-422: Is rated at 8 milliradians, while the much larger and considerably heavier 30mm GAU-8 Avenger is rated at 5 milliradians. The CRV7 had just been introduced into Royal Canadian Air Force service when it was entered as a part of a general competition in France. One part of the competition required the contestants to hit a tower with unarmed rockets. The Canadian pilot hit it on his first try, but aimed as if firing

1960-473: Is the ability of an explosive to be stored without deterioration . The following factors affect the stability of an explosive: The term power or performance as applied to an explosive refers to its ability to do work. In practice it is defined as the explosive's ability to accomplish what is intended in the way of energy delivery (i.e., fragment projection, air blast, high-velocity jet, underwater shock and bubble energy, etc.). Explosive power or performance

2030-411: Is the lead-free primary explosive copper(I) 5-nitrotetrazolate, an alternative to lead azide . Explosive material may be incorporated in the explosive train of a device or system. An example is a pyrotechnic lead igniting a booster, which causes the main charge to detonate. The most widely used explosives are condensed liquids or solids converted to gaseous products by explosive chemical reactions and

2100-407: Is used to describe an explosive phenomenon whereby the decomposition is propagated by a shock wave traversing the explosive material at speeds greater than the speed of sound within the substance. The shock front is capable of passing through the high explosive material at supersonic speeds   —   typically thousands of metres per second. In addition to chemical explosives, there are

2170-541: The AGM-114 Hellfire . A version of the CRV7-PG was also developed for special forces use, fired from a single tube mounted on a 6 x 6 vehicle. CARDE DRDC Valcartier is a major Canadian military research station at Canadian Forces Base Valcartier , Quebec , one of nine centres making up Defence Research and Development Canada (DRDC). Originally formed at the end of World War II in 1945 as

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2240-734: The Canadian Armament Research and Development Establishment ( CARDE ), the intent was to keep the research teams built up during the war in Canada, as opposed to moving to the United States. Starting in 1951 CARDE implemented a major missile development program, eventually delivering two combat systems, the Velvet Glove air-to-air missile and the Heller anti-tank rocket. Neither was accepted for production, but

2310-581: The C-14 engine generated considerable amounts of smoke. While suitable for high-speed aircraft that quickly clear the plume, it is not suitable for slower aircraft and helicopters which would be flying in the smoke for some period of time. This problem led to the development of the RLU-5002/B (C-15) engine, which did not include aluminium and produced considerably less smoke, with a slightly lower impulse of 2,185 lbf·s (9.7 kN·s). The original C-15 used

2380-581: The RA-79 from Raufoss Ammunisjonsfabrikker, a semi-armor-piercing round designed to attack shipping. The CRV7 Multi-Purpose Sub Munition (MPSM) contained nine M73 submunitions in each rocket. It could therefore be classified as a cluster bomb . Britain destroyed the last of its CRV7 MPSMs in July 2009 in accordance with its interpretation of the Convention on Cluster Munitions . In 2006 Bristol started testing

2450-413: The aforementioned (e.g., nitroglycerin , TNT , HMX , PETN , nitrocellulose ). An explosive is classified as a low or high explosive according to its rate of combustion : low explosives burn rapidly (or deflagrate ), while high explosives detonate . While these definitions are distinct, the problem of precisely measuring rapid decomposition makes practical classification of explosives difficult. For

2520-406: The basic research was used with local defence contractors to build up familiarity with the new technologies. Starting in 1955 a serious effort to equip Canada with a useful anti–ballistic missile system was undertaken, along with research into the problems of detection and tracking, hypersonic flight, and fuels suitable for use in an interceptor missile. As part of this project a lengthy study of

2590-479: The capacity of an explosive to be initiated into detonation in a sustained manner. It is defined by the power of the detonator which is certain to prime the explosive to a sustained and continuous detonation. Reference is made to the Sellier-Bellot scale that consists of a series of 10 detonators, from n. 1 to n. 10 , each of which corresponds to an increasing charge weight. In practice, most of

2660-486: 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 also be categorized by their sensitivity . Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary or tertiary explosives . A wide variety of chemicals can explode;

2730-425: The choice being determined by the characteristics of the explosive. Dependent upon the method employed, an average density of the loaded charge can be obtained that is within 80–99% of the theoretical maximum density of the explosive. High load density can reduce sensitivity by making the mass more resistant to internal friction . However, if density is increased to the extent that individual crystals are crushed,

2800-488: The development of a dedicated antitank warhead that replaced the steel rod in the practice warhead with a tungsten rod. This new antitank warhead could penetrate a Soviet T-72 main battle tank armour from any attack angle. Further study into this effect led to the WDU-5002/B FAT warhead, Flechette Anti-Tank , containing five tungsten -reinforced steel flechettes that could penetrate a T-72's side and top armour at

2870-421: The development of pressure within rounds of ammunition and separation of mixtures into their constituents. Volatility affects the chemical composition of the explosive such that a marked reduction in stability may occur, which results in an increase in the danger of handling. The introduction of water into an explosive is highly undesirable since it reduces the sensitivity, strength, and velocity of detonation of

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2940-498: The energy of the detonation. Once detonated, the nitrogen portion of the explosive formulation emerges as nitrogen gas and toxic nitric oxides . The chemical decomposition of an explosive may take years, days, hours, or a fraction of a second. The slower processes of decomposition take place in storage and are of interest only from a stability standpoint. Of more interest are the other two rapid forms besides decomposition: deflagration and detonation. In deflagration, decomposition of

3010-492: The energy on impact. Its maximum effective range is over 4,000 m, allowing launch from beyond the envelope of most short-range anti-aircraft weapons. In comparison, the Mighty Mouse or Hydra 70 requires launches from much shorter ranges, potentially placing the launch aircraft within the range of ground-based weapons arranged around the target. Unguided rockets are normally spin stabilized like rifle bullets. The spin

3080-604: The energy released by those reactions. The gaseous products of complete reaction are typically carbon dioxide , steam , and nitrogen . Gaseous volumes computed by the ideal gas law tend to be too large at high pressures characteristic of explosions. Ultimate volume expansion may be estimated at three orders of magnitude, or one liter per gram of explosive. Explosives with an oxygen deficit will generate soot or gases like carbon monoxide and hydrogen , which may react with surrounding materials such as atmospheric oxygen . Attempts to obtain more precise volume estimates must consider

3150-445: The explosive material is propagated by a flame front which moves relatively slowly through the explosive material, i.e. at speeds less than the speed of sound within the substance (which is usually still higher than 340 m/s or 1,220 km/h in most liquid or solid materials) in contrast to detonation, which occurs at speeds greater than the speed of sound. Deflagration is a characteristic of low explosive material. This term

3220-651: The explosive material, but a practical explosive will often include small percentages of other substances. For example, dynamite is a mixture of highly sensitive nitroglycerin with sawdust , powdered silica , or most commonly diatomaceous earth , which act as stabilizers. Plastics and polymers may be added to bind powders of explosive compounds; waxes may be incorporated to make them safer to handle; aluminium powder may be introduced to increase total energy and blast effects. Explosive compounds are also often "alloyed": HMX or RDX powders may be mixed (typically by melt-casting) with TNT to form Octol or Cyclotol . An oxidizer

3290-442: The explosive may become more sensitive. Increased load density also permits the use of more explosive, thereby increasing the power of the warhead . It is possible to compress an explosive beyond a point of sensitivity, known also as dead-pressing , in which the material is no longer capable of being reliably initiated, if at all. Volatility is the readiness with which a substance vaporizes . Excessive volatility often results in

3360-414: The explosive properties of two or more compounds; it is important to examine the data from several such tests (sand crush, trauzl , and so forth) in order to gauge relative brisance. True values for comparison require field experiments. Density of loading refers to the mass of an explosive per unit volume. Several methods of loading are available, including pellet loading, cast loading, and press loading,

3430-409: The explosive. Hygroscopicity is a measure of a material's moisture-absorbing tendencies. Moisture affects explosives adversely by acting as an inert material that absorbs heat when vaporized, and by acting as a solvent medium that can cause undesired chemical reactions. Sensitivity, strength, and velocity of detonation are reduced by inert materials that reduce the continuity of the explosive mass. When

3500-429: The explosives on the market today are sensitive to an n. 8 detonator, where the charge corresponds to 2 grams of mercury fulminate . The velocity with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1,800 m/s to 8,000 m/s. Today, velocity of detonation can be measured with accuracy. Together with density it

3570-413: The first time in warfare. The Chinese would incorporate explosives fired from bamboo or bronze tubes known as bamboo firecrackers. The Chinese also inserted live rats inside the bamboo firecrackers; when fired toward the enemy, the flaming rats created great psychological ramifications—scaring enemy soldiers away and causing cavalry units to go wild. The first useful explosive stronger than black powder

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3640-532: The history of chemical explosives lies in the history of gunpowder . During the Tang dynasty in the 9th century, Taoist Chinese alchemists were eagerly trying to find the elixir of immortality. In the process, they stumbled upon the explosive invention of black powder made from coal, saltpeter, and sulfur in 1044. Gunpowder was the first form of chemical explosives and by 1161, the Chinese were using explosives for

3710-509: The launch tube, greatly increasing accuracy. A salvo of CRV7's will impact the target area in one-third the footprint of older designs. The weapon was originally quoted to have a dispersion of 4 milliradians , but testing with the McDonnell Douglas CF-18 Hornet demonstrated it was even lower, at 3 milliradians. This is considerably better than the autocannon that arm most aircraft; the widely used 20mm M61 Vulcan

3780-450: The manufacturing operations. A primary explosive is an explosive that is extremely sensitive to stimuli such as impact , friction , heat , static electricity , or electromagnetic radiation . Some primary explosives are also known as contact explosives . A relatively small amount of energy is required for initiation . As a very general rule, primary explosives are considered to be those compounds that are more sensitive than PETN . As

3850-453: The midcourse and homes during the terminal approach using a laser designator . Other versions offer anti-radiation seeking or GPS guidance. The precision guided kit includes the addition of tail fins and an in-flight control system. Combining the laser seeker with the FAT warhead produces a capable long-range anti-tank missile that is faster and much less expensive than traditional platforms like

3920-436: The moisture content evaporates during detonation, cooling occurs, which reduces the temperature of reaction. Stability is also affected by the presence of moisture since moisture promotes decomposition of the explosive and, in addition, causes corrosion of the explosive's metal container. Explosives considerably differ from one another as to their behavior in the presence of water. Gelatin dynamites containing nitroglycerine have

3990-443: The molecule is said to have a zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed. The sensitivity, strength , and brisance of an explosive are all somewhat dependent upon oxygen balance and tend to approach their maxima as oxygen balance approaches zero. A chemical explosive may consist of either

4060-457: The more important characteristics are listed below: Sensitivity refers to the ease with which an explosive can be ignited or detonated, i.e., the amount and intensity of shock , friction , or heat that is required. When the term sensitivity is used, care must be taken to clarify what kind of sensitivity is under discussion. The relative sensitivity of a given explosive to impact may vary greatly from its sensitivity to friction or heat. Some of

4130-425: The much lower-powered Mk 40 and was therefore close enough that the rocket motor was still firing. The remaining unburned propellant shattered, allowing more surface area of the rocket motor to burn, in turn increasing the pressure and rate of combustion until it became a deflagration that destroyed the tower. The pilot was disqualified because the judges refused to believe it was unarmed. The aluminium -based fuel in

4200-569: The new propellant as the basis for a new motor for existing 2.75-inch air-to-ground rockets. The result was the CRV-7 rocket, which had roughly twice the speed of the existing US design, and with enough energy to be able to puncture Warsaw Pact aircraft hangars. Production started at Bristol Aerospace in 1974, and the CRV-7 has been used by the Canadian and other air forces since that time. In 1969

4270-491: The original CRV7 was the U.S. M151 High Explosive Point Detonating (HEPD) round, a simple impact-fired 10 lb (4.5 kg) high-explosive shell. Like the U.S. 2.75-inch (70 mm) weapons, the CRV7 could also be equipped with the M156 Smoke or M257/278 Illumination ( flare ) rounds. Bristol also introduced their own WTU-5001/B Practice round, consisting of an 8 lb (3.6 kg) flat-ended soft steel rod encased in

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4340-410: The possibility of such side reactions, condensation of steam, and aqueous solubility of gases like carbon dioxide. Oxygen balance is an expression that is used to indicate the degree to which an explosive can be oxidized. If an explosive molecule contains just enough oxygen to convert all of its carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide with no excess,

4410-426: 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: Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of

4480-461: The round to penetrate the hangar wall before the 75 g incendiary warhead is ignited. The round can penetrate 13 ft (4.0 m) of earth, 3 ft (91 cm) of concrete, and 1 in (25 mm) of steel, in series. The CRV7's kinetic energy was so high that testers were surprised to find that practice rounds fitted with an 8-inch (20.3 cm) steel rod were penetrating outdated Centurion tanks used for target practice. This resulted in

4550-492: The sum of the masses of the two initial layers. There are applications where a shock wave, and electrostatics, can result in high velocity projectiles such as in an electrostatic particle accelerator . An explosion is a type of spontaneous chemical reaction that, once initiated, is driven by both a large exothermic change (great release of heat) and a large positive entropy change (great quantities of gases are released) in going from reactants to products, thereby constituting

4620-499: The test methods used to determine sensitivity relate to: Specific explosives (usually but not always highly sensitive on one or more of the three above axes) may be idiosyncratically sensitive to such factors as pressure drop, acceleration, the presence of sharp edges or rough surfaces, incompatible materials, or even —  in rare cases —  nuclear or electromagnetic radiation. These factors present special hazards that may rule out any practical utility. Sensitivity

4690-425: The two layers. As the length of time the shock wave spends at any point is small, we can see mixing of the two metals and their surface chemistries, through some fraction of the depth, and they tend to be mixed in some way. It is possible that some fraction of the surface material from either layer eventually gets ejected when the end of material is reached. Hence, the mass of the now "welded" bilayer, may be less than

4760-534: The upper atmosphere was undertaken from instrumented balloons. Another development from this era was the use of gun-fired models for high-speed testing, instead of using a wind tunnel . Led by Gerald Bull , the sabot –based system would go on to be used in Project HARP during the early 1960s. The early portions of the 1960s was taken up developing a series of increasingly powerful high-acceleration solid rocket propellants, and to test them they designed and built

4830-799: Was nitroglycerin , developed in 1847. Since nitroglycerin is a liquid and highly unstable, it was replaced by nitrocellulose , trinitrotoluene ( TNT ) in 1863, smokeless powder , dynamite in 1867 and gelignite (the latter two being sophisticated stabilized preparations of nitroglycerin rather than chemical alternatives, both invented by Alfred Nobel ). World War I saw the adoption of TNT in artillery shells. World War II saw extensive use of new explosives (see: List of explosives used during World War II ) . In turn, these have largely been replaced by more powerful explosives such as C-4 and PETN . However, C-4 and PETN react with metal and catch fire easily, yet unlike TNT, C-4 and PETN are waterproof and malleable. The largest commercial application of explosives

4900-521: Was renamed " Defence R&D Canada – Valcartier " when the overseeing organisation became the Defence Research and Development Canada agency. Other DRDC locations in Canada : High-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

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