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Electrically exploded wires find uses throughout high-energy physics. For example, they are commonly used as high-temperature sources, X-ray generators, and in precision timing detonators. However, the detailed and complete physics that occurs is complex and still poorly understood. A full mechanistic description of these complex phenomena is beyond the scope of a single paper. Instead, we focus on the formation of metal vapor and its transition to plasma. This single transition is commonly assumed to comprise “bridge-burst”. We use a suite of diagnostics including a novel, fiber-based, high-speed, optical pyrometer to better characterize this transition. The primary finding from this project is that peak light output from an exploding wire does not temporally match the peak temperature. Additionally, it is found that peak light does not align with peak bridge-burst voltage and that the peak temperature is not voltage-dependent. These findings are non-intuitive and will allow for the correction of false assumptions previously made about this topic.

A prototype of WiFi based wireless blasting system aimed to achieve simple and easy detonation techniques. Since the invention of explosives world has used various detonation techniques, this prototype is developed to further simplify the detonation techniques. The speciality of this detonator is that it can trigger most forms of explosives and can also ignite a controlled fire without any explosive.

Everybody knows TNT, the most widely used explosive material and a universal measure of the destructiveness of explosions. A long history of use and extensive manufacture of toxic TNT leads to the accumulation of these materials in soil and groundwater, which is a significant concern for environmental safety and sustainability. Reliable and cost-efficient technologies for removing or detoxifying TNT from the environment are lacking. Despite the extreme urgency, this remains an outstanding challenge that often goes unnoticed. We report here that highly controlled energy release from explosive molecules can be accomplished rather easily by preparing TNT–perovskite mixtures with a tailored perovskite surface morphology at ambient conditions. These results offer new insight into understanding the sensitivity of high explosives to detonation initiation and enable many novel applications, such as new concepts in harvesting and converting chemical energy, the design of new, improved energetics with tunable characteristics, the development of powerful fuels and miniaturized detonators, and new ways for eliminating toxins from land and water.

In China, mining blasting vibration has seriously threatened the safety and stability of high and steep rock slopes. In this paper, taking the east mining area of Jianshan Phosphorus Mine as the research background, combined with field survey, field blasting test, numerical simulation and theoretical analysis, we systematically studied the adjacent high-steep rock slope and the layered blasting technology of complex ore. Based on wide hole spacing blasting numerical simulation and field tests, the use of 8 × 4 m hole network parameters, oblique line hole-by-hole initiation method, detonator delay using 35 ms between holes, 65 ms between rows and 500 ms within the holes, the rock mass rate was reduced and the drilling workload was decreased. In addition, regression analysis was carried out on a large amount of vibration test data, and the attenuation law and propagation law of blasting vibration of adjacent high and steep slopes were predicted, which provided a reference for mine production blasting. By establishing a mathematical model of cumulative damage of rock mass blasting, it shows that the depth of impact of mining blasting on the slope of Jianshan open-pit was 0–3.6m, but the blasting did not cause overall damage to the adjacent high and steep slopes. In the future, this model can be used to predict rock damage caused by subsequent blasting.

In this paper, the effect of grain size and micromorphology of Cu foil on the velocity of the flyer of an exploding foil detonator was studied. A Cu foil with different grain sizes and micromorphologies was prepared by the physical vapor deposition sputtering method. The flyer velocity of the Cu foil was measured by the photon Doppler technique (PDT). The influence of the grain size and micromorphology of the Cu foil (which was the core transducer of the exploding foil detonator) on the flyer velocity and reacted morphology was discussed. The results show that the grain size and micromorphology of the Cu film can greatly affect the velocity and morphology of the flyer. The grain size of the Cu film is more uniform, and the stimulus response in the middle area of the bridge foil is more concentrated. In addition, the current density becomes more uniform, resulting in a better explosion performance. Consequently, the speed of the formed flyer becomes higher, leading to a smoother flyer surface, which is more conductive to energy conversion.

Deep-hole blasting and chamber blasting technology are widely used in mining and large-scale earth-rock excavation or landfill projects, due to their advantages of high efficiency and low cost. However, their use is often accompanied by misfire accidents, and generally misfire is relatively hidden, as well as difficult to quickly detect and identify, making misfire the greatest potential safety hazard in blasting construction. This paper presents a method and system of frequency division multiple access (FDMA) detection and recognition for blasting misfire, based on electromagnetic wave propagation theory and radio frequency identification technology. Next, the feasibility of frequency division multiple access (FDMA) misfire detection method is analyzed by means of theoretical deduction. Combining field and laboratory tests, it is concluded that the existence of underground misfire with a linear distance of 225 m can be detected. In addition, the detection frequency range is 975-5025 Hz, and the recognition accuracy of multi-frequency signal can reach 2 Hz. The stability of the electric detonator in an electromagnetic environment is discussed, and the danger criterion of the electric detonator in the electromagnetic environment is obtained. When the power of the signal transmitter is less than 120 W and the induction area of the electric detonation network is less than 0.5 m2, then the electric detonator is safe. The misfire detection and recognition system has been successfully applied in a deep-hole blasting of an open-pit quarry. It is observed that when the distance between millisecond blasting holes is equal to greater than 5 m, the detection signals between holes will not interfere with each other. This paper provides a reliable, systematic and complete research method for remote wireless detection and identification of misfire, and also provides a basis for the safety of blasting construction and misfire detection in related projects.

The major technical challenge facing the detection of individual mine lies on having the ability to discriminate landmines from metal debris, natural clutters, and other objects without the need for vegetation cutting. Future efforts to improve detection should focus on providing discrimination capabilities that includes the fusion of information coming from multi heterogeneous and/or homogenous sensors, and the incorporation of advanced signal processing techniques to support real-time processing and decision making. For the purpose of mine clearance, there is an urgent need to have cost-effective and efficient clearance techniques and technologies to clear landmines in different types of terrain and under different climate variations. This should be associated with neutralization of mines, in which there is a need to develop safe, reliable, and effective methods to eliminate the threat of individual mines without moving them while minimizing environmental and ecological effects. Working in a minefield is not an easy task for a robot. Hostile environmental conditions and strict requirements dictated by demining procedures make development of demining robot a challenge. Demining robots and intelligent mechanisms offer a challenging opportunity for applying original concepts of robotic design and control schemes, and in parallel to this there is urgent need to develop new mine detection techniques and approaches for sensor integration, data fusion, and information processing. Difficulties can be recognized in achieving a robot or other mechanical solutions with specifications that can fulfill the stated requirements for humanitarian demining. A lot of demining tasks cannot yet be carried out by the available robots because of their poor locomotive mechanism and mobility in different type of terrains. This is because there is still lack of well-adopted locomotion concepts for both outdoor and off-road locomotion. Hence

Lead(II) azide is an initiating explosive, even a small amount can trigger an explosion caused by simple external stimuli, such as sparks, flames, friction or pinpricks, and is able to initiate the explosive reaction of rock-crushing explosives. Due to the fact that this initiating explosive triggers further reactions, the effect of priming detonators depends on the properties of its material. Its sensitivity is associated with the size of its crystals. For instance, it is used for mining detonators in the form of fine crystals. The quality of the crystals is also correlated to the safety of the production process, i.e., the crystals should be round-shaped rather than needle-like since breaking it would inevitably trigger an explosion. The process of lead(II) azide production on an industrial scale is based on the reaction of lead(II) nitrate with sodium azide with the presence of dextrin, which determines the desired shape of the crystals. The reaction pH affects the number of sediment particles formed in a periodical reactor. Changing the pH from 6.5 to 7.5 leads to the rapid growth of crystal particles.

In order to effectively reduce the disturbance of the precrack blasting vibration on slope rock mass, except paying attention to the damping effect of the precrack, it is also necessary to optimize the blasting parameters and initiation mode of the precrack itself. Based on the blasting theory and empirical formula, the parameters of presplitting blasting such as the hole diameter, hole spacing, charge decoupling coefficient, and line charge density were determined, and field tests of conventional pre-splitting blasting and presplitting blasting with precise delay and hole-by-hole initiation were carried out on the west slope of Buzhaoba. Regression analysis was carried out on the vibration monitoring data, and the blasting vibration attenuation regularity of slope particles was obtained. By comparing the monitored vibration velocity of the two presplitting blasting tests and the forecast results of theoretical calculation, the average reduction rate of the conventional same row blasting vibration is 26.40%, while that of the hole-by-hole blasting vibration can reach 41.45% with a half hole rate of 80.7% and an irregularity of about 130 mm. Results show that the effect of precise delay initiation between preholes based on the digital electronic detonator is better than that of the simultaneous initiation of preholes. Therefore, it is suggested that the hole-by-hole presplitting blasting technology should be applied in the excavation of boundary slope and the treatment of high and steep slope.

In order to study the damage characteristics of polymer plates under the impact of the underwater explosion, the underwater contact and near-field explosion tests of polymer plates were conducted using different explosive quantities. In this paper, eight polymer plates with the size of 500 mm × 500 mm × 60 mm were made, and eight groups of explosion tests were carried out by using the rock emulsion explosive and nonconductive detonators. The damage modes and spatial distribution characteristics of the polymer plate generated by the underwater contact and near-field explosion impact with different explosive quantities are compared and analyzed. In addition, the characteristics of the shock wave propagation in the plates are investigated. It can be observed that the main damage mode of polymer plate is overall damage under the contact underwater explosion. For the near-field explosion, the main damage mode changes to overall failure, and the damage of contact explosion to polymer plate is greater than that of underwater near-field explosion. The polymer plate can reduce and delay the shock wave effectively, but the effect decreases with the increase of explosive quantity in the underwater contact explosion.

This study analyzes the main causes of accidents in the period of coal mine shaft construction and the shortage of the existing safety monitoring technology, puts forward the intelligent safety monitoring robot technology based on shaft construction, and deeply investigates the functions that the safety monitoring robot should have. Besides, the research objective of intelligent safety monitoring robot for shaft construction is pointed out, and the research is carried out from such aspects as the robot body structure, walking mechanism, adsorption mechanism, control, communication, intelligent sensing, hazard source recognition, recognition of explosive detonators, and software platform development. As well, this study designs the technical device of intelligent safety monitoring robot for shaft construction, defines the characteristics of this technology, expounds the important significance of studying this technology, and indicates the development trend of this technology.

To improve the productivity and efficient of modern large-scale open-cut mines, a number of technologies are developed and trialed, including new blasting equipment, larger blasting holes, high benches, air spacing, and short-delay blasting within holes. However, the relative blasting parameters need field calibration and further investigation of theories on these techniques are required. This paper studied the open-cut bench blasting at Barun Eboxi Mine of Baotou Iron and Steel Group via theoretical analysis on shock wave, numerical simulation, and field test. According to the technical conditions of the site, three sets of vertical boreholes at 310 mm diameter were drilled on 24 m high batter; and three sets of air-spaced charges were set up. The digital electronic detonator was used to initiate at millisecond intervals. The study found that under the condition of 24 m high bench, the use of intermediate air interval is beneficial to the rock fragmentation. The delay time within the hole is 3-8 ms. The bottom of the lower explosives and the top of the upper explosives were devised for initiation to optimize the initiation location. The peak effective stress points are 63.6%, 52.2%, and 8.9% higher, respectively. The field test of high-bench intrahole millisecond blasting in Barun Eboxi mine shows that the intrahole millisecond blasting parameters proposed in this study are feasible.

An electronic fuze is a one-shot system that has a long storage life and high mission criticality. Fuzes are designed, developed, and tested for high reliability (over 99%) with a confidence level of more than 95%. The electronic circuit of a fuze is embedded in the fuze assembly, and thus is not visible. Go/NoGo fuze assembly mission critical testing does not provide prognostic information about electrical and electronic circuits and subtle causes of failure. Longer storage times and harsh conditions cause degradation at the component level. In order to calculate accrued damage due to storage and operational stresses, it is necessary to perform sample-based accelerated life testing after a certain time and estimate the remaining useful life of mission critical parts. Reliability studies of mechanical parts of such systems using nondestructive testing (NDT) have been performed, but a thorough investigation is missing with regards to the electronic parts. The objective of this study is to identify weak links and estimate the reliability and remaining useful life of electronic and detonating parts. Three critical components are identified in an electronic fuze circuit (1) a diode, (2) a capacitor, and (3) a squib or detonator. The accelerated test results reveal that after ten years of storage life, there is no significant degradation in active components while passive components need to be replaced. The squib has a remaining useful life (RUL) of more than ten years with reliability over 99%.

Pentaerythritol tetranitrate (PETN) is a commonly used high explosive (HE) in detonators. Often, surrogate or &ldquo, mock&rdquo, materials are used in place of HE for mechanical tests, proofing out equipment, or developing new diagnostics. However, there is no commonly accepted mock for PETN. A good mock should match at least one physical property of the target material, and ideally mimic multiple thermal and mechanical properties. Here, we investigate several molecular crystals to evaluate their efficacy in mocking PETN density, melting point, elastic modulus, hardness, plastic deformation, and fracture behavior. Materials were tested with a combination of calorimetry and nanoindentation. Two materials, 2,4,6-trifluorobenzoic acid (246 TFBA) and mesoerythritol, were downselected for detailed indentation study after the initial round of screening experiments, both were found to mimic PETN mechanical behavior quite well, 246 TFBA closer to PETN in most properties (hardness, modulus, and density) than erythritol, but erythritol having advantages in relative cost and matching the onset of yield. Depending on the desired implementation of the mock, one material may be preferred over the other, but both have potential as generic mocks for PETN. Nanoindentation is demonstrated as a versatile tool to provide rapid screening of these materials&rsquo, mechanical properties.

To ensure the safe and efficient excavation of ultradeep foundation pits in a complex urban environment, the ultradeep foundation pit excavation project of Liuguangmen Urban Complex in Guiyang City was taken as the study point. A high-efficiency blasting method was proposed for the excavation of vibration-isolating slot and electronic detonators, and a three-dimensional spatial calculation model of the foundation pit structure was established. In addition, the field test and numerical simulation of the blasting vibration were developed. The feasibility of the high-efficiency blasting method was demonstrated, and the propagation law of the dynamic response characteristic parameters of the structure was explored using an electronic detonator and vibration-isolating slot. The results show that the electronic detonator carried out peak shaving within the group, unloading waves between the groups, and the blocking effect of the vibration-isolating slot, and all these effectively reduced the peak stress and peak particle vibration velocity, evenly distributed the vibration velocity, and guaranteed the safety of the surrounding existing buildings, proving the feasibility of the efficient blasting method. There is a “wall effect” at the supporting pile, whose propagation velocity is lower than that inside the rock mass, and the PPV is radial X > tangential Y > vertical Z. The peak values of stress, strain, and PPV all decrease with increasing supporting pile height, and there is an inflection point at 20 m. The internal nodes of the pile reciprocate without sharp change and failure in displacement. The peak displacement of different nodes is in the order X > Y > Z with increasing pile height, and the maximum peak value is 0.08 mm.

The outcome of bench blasting significantly affects the downstream operations in mining. In bench blasting, the explosives charged in blastholes are generally cylindrically shaped and fired by the in-hole detonator. As the detonator determines the propagation of the detonation wave in the cylindrical charge, the effect of detonator location can never be ignored. In this paper, the mathematics and mechanics of the effect of detonator location was analyzed from the view of the distribution of explosion energy and blast stress field of a cylindrical charge. Then, a field blasting experiment and two numerical simulations were conducted to further display its effect on blasting outcomes. At last, the appearance of oversize boulders and rock toes in bench blasting was discussed, and an improved scheme of the detonator location was proposed to cope with these problems. Results indicate that the in-hole detonator has the capacity of adjusting the spatial distribution of explosion energy and blast stress field in the surrounding rock mass. The traditional recommendation of the bottom detonator is not always right. The optimized detonator location in bench blasting is available by properly combining the merits of traditional detonator locations. This study is of interest to improve the efficiency and reduce the cost of mining.

The delay-time of detonators in hole-by-hole blasting is generally calculated accurately considering they have great influence on the blasting effect, such as blasting vibration and blasting slungshot. The high-precision nonel detonator and digital electronic detonator are been commonly used because of their accuracy of delay-time. However, each detonator has an allowable error range of delay-time due to the difference in manufacturing process. In the initiation network, the errors of delay-time often accumulate gradually as the number of detonators increases. Therefore, theoretical delay-time and actual delay-time with error in the detonating network were discussed based on the delay-time errors of detonators. The single-factor variable method was used to carry out the comparative test in deep hole blasting. The results showed that the particle peak vibration velocity (PPV) was 13.1783 cm/s and 3.4856 cm/s with a drop of 73.55% in comparison with a nonel detonator and digital electronic detonator, which proved that hole-by-hole blasting in the high-precision nonel detonator network was not achieved due to the delay error of detonators. Furthermore, the location distribution map of holes where the same section of detonators might occur was obtained. Finally, the probability of blasting in the same section changes with the number of blast holes was discovered by theoretical analysis, which provided a basis for accurate hole-by-hole blasting.

An introduction to exploding bridge-wire (EBW) detonators is given followed by an extensive critical review of open source literature pertaining to these devices. The aim is to better establish the mechanism of operation. Some authors state that the key mechanism is shock-to-detonation while others maintain it is more thermal in nature, or a complex combination of both. In addition to EBW detonators, arc detonators and direct optical initiation detonators are also reviewed, and it is demonstrated that in this manner the usually coupled effects from both shock and deflagration can be somewhat decoupled. As a result, it is hypothesized that the mechanism of operation in all three detonators is in fact the same: the formation of a hot plasma with a power of ≈1 MW and emission in the ultraviolet drives a thermal explosion process.

The purpose is to study the effect of microstructure defects of initiating explosives on the process of initiating detonation by a laser monopulse. The results of experimental studies and physico-mathematical modeling of the effect of microstructural defects in crystals of photosensitive initiating explosives under the action of a single laser pulse are given. The paper covers a brief analysis of the history of the issue being studied and physico-mathematical modeling using the theory of elastic scattering, i.e. Gustav Mie theory. The technique for determining the absorption cross section of laser radiation by micro-sized inclusions of explosive has been developed and tested. In experiments on explosives ignition using a laser monopulse, the laser monopulse shape was recorded, the energy distribution over the laser beam radius and the explosive ignition delay time were controlled. The basis is the proposed method of calculating the absorption cross section and intensity in terms of the laser radiation wavelength by the inclusion of an explosive with using the theory of elastic scattering of optical radiation on particles in micrometer size range. It is shown that the absorption properties of the particle essentially depend on the properties of the particle medium and the wavelength of radiation. For smoke particle within PETN the absorption for wavelength of laser radiation of 1.06 μm is stronger than for that of 0.69 μm. A different absorption occurs if a lead particle is within a lead azide: absorption for wavelength of 0.69 μm is twice as strong as for wavelength of 1.06 μm. During the manufacture of explosives the additional defects in the explosives microstructure are desired to be created to increase the efficiency of laser initiation. Findings are used in the development of technical specifications for the design of optical detonators for laser initiation systems.

The topicality of the present work lies in justification of the means of increasing safety during mass explosions in opencasts. The solution to this problem is possible due to the orientation of downholes in the array, taking into account the angle of incidence and extension of the strata, high-quality stemming and initiation of downhole charges by delay detonators with a minimal deviation from nominal values of their firing time. The most promising way to increase the safety and efficiency of blasting is an integrated approach, including drilling downholes, normal to the strata, and using the design of the downhole charge, rationally distributing the explosion energy in the space of the rock mass due to the use of stemming of a variable density, low-density gap between the parts of the explosive charge and the bottom a downhole compensator based on foam gel and the use of hybrid electronic detonator Iskra-T.