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For aerospace vehicles, notably missiles or satellites for attitude and divert control, impulsive thrusters are most desirable if they are quantized as exact instantaneous pulses available over and after extended periods of inactive storage. These thrusters operate for a few milliseconds (ms), typically between 10 ms to 100 ms duration. Compared to its liquid or gaseous counterpart, an impulsive thruster powered by solid propellants is a simple, and reliable solution. Therefore, they are suitable as reaction control systems and divert thrusters for satellite and unmanned aerial vehicle applications.A typical solid propellant would need an extremely thin web thickness for port burning arrangement due to its brief burn duration, which makes propellant manufacturing and its structural anchoring in motor challenging. A high burn rate and high-density propellant based on ammonium perchlorate, aluminum, and Teflon is processed to enable end-burning configuration thus solving the problems, simplifying propellant manufacturing, structural design and integration. It also permits stacking propellants for multi-pulse applications. The high burn rate (40 mm/s at 120 bar pressure) propellant is formulated and tested for ballistic performance evaluation in proof motor configuration, and evaluation of its advantages over conventional propellant. A case of identical design requirements with both double base propellant and high burn rate pressed propellant is compared, tested and evaluated to compare the relative performance merits. The volumetric load is increased from 47% to 82% due to the development and adoption of high burn rate propellant. The overall weight of the thruster is also reduced by 20%.

In order to study the combustion characteristics and reaction mechanism of luminescent pyrotechnics under sub-atmospheric pressure conditions, low-pressure combustion tests and thermal analysis were performed for magnesium/sodium nitrate pyrotechnics with zero oxygen equilibrium in the pressure range of 1 kPa~101 kPa. The results reveal that when the pressure drops, the flame height rises, and the flame transitions from a steady-state convergent to a turbulent evanescent flame. Reduced oxygen concentration at low pressure reduces the flame's high temperature response zone, as well as burning speed and luminous intensity. Furthermore, both the light intensity and the burning rate comply with Vier's law. The weight loss increased from 16.3% to 36.7% when the pressure was reduced from atmospheric pressure to 1 kPa, the enthalpy change of reaction decreased from 6.75 kJ/g to 2.45 kJ/g, and the characteristic peak of magnesium oxide at 500 nm in the flame spectrum disappeared at 1 kPa, indicating that the reduction of pressure would affect the degree of reaction of pyrotechnics, leading to the decrease of magnesium oxide content and the decrease of heat release. These scientific findings provide useful insights into the low-pressure combustion behavior of pyrotechnics and support the growing demands for military and civilian applications. [ABSTRACT FROM AUTHOR]

The burning of fireworks damages air quality by causing elevated concentrations of particulate matter (PM2.5 and PM10) in short periods of time. In this context, the research aimed to compare airborne concentrations of PM2.5 and PM10 from fireworks with the National Ambient Air Quality Standards (NAAQS) and the World Health Organization (WHO) guideline. The applied methodology involved the use of the PRISMA 2020 statement. The literature review was conducted on digital databases such as Scopus, ScienceDirect, Taylor & Francis, Wiley, and Ebsco. Annual growth in scientific production was calculated using a digital tool (Calcuvio), and data analysis was performed using Microsoft Office Excel and VOSviewer. The annual growth in production (1999 to 2022) was 18.74%. The highest scientific production per year was concentrated in 2019 and 2020, with China being the leading country. The festivities where sound pressure levels were predominantly measured were during the Spring Festival and Diwali. The most frequently mentioned keywords were "fireworks" and "PM2.5". In conclusion, the percentage of studies that exceeded the NAAQS for PM2.5 and PM10 was 2% and 15%, respectively, while for the WHO guideline, it was only 1% for PM10. [ABSTRACT FROM AUTHOR]

Firework noise, generated in short bursts, poses health risks. The objective of the research was to compare the sound pressure levels generated by fireworks with the World Health Organization's (WHO) noise guidelines. The methodology employed was the 2020 PRISMA statement. The bibliographic review was conducted using digital databases such as Scopus, ScienceDirect, Taylor & Francis, Wiley, and EBSCO. To determine the annual growth of scientific production, a digital tool was utilized, and data analysis was performed with Microsoft Office Excel and VOS viewer. The annual growth of scientific production between 1975 and 2022 was 6.47%. The geographical distribution of studies by year and country was concentrated in 2013 and in India, with 3 and 13 publications, respectively. The festival where the most sound pressure levels were measured was Diwali, with 8 studies. The author with the highest number of citations was Overall K., with 161 citations, and the keyword with the highest number of occurrences was "fireworks" (18 instances). It is concluded that 100% (19) of the studies exceeded the WHO's desirable upper limit value for outdoor noise. This finding is concerning because it directly affects people's health. Consequently, governments should implement strategies to minimize the negative impacts generated by fireworks. [ABSTRACT FROM AUTHOR]

In times of peace and except for terrorist attacks, fatalities by explosions are rare. Fireworks have deadly potential, especially self-made or illegally acquired devices. The use of professional pyrotechnics by untrained persons poses a life-threatening hazard. We present a case of devastating blunt force and blast injuries to the head and chest of a young man. After ignition of a display shell (syn. a real shell or mortar shell) without the use of a launching pipe, the device hit the man's face, nearly simultaneously followed by the explosion of the burst charge. The autopsy revealed injuries to the face and forehead as well as extensive tissue structure damage and a massive contusion with a bloody edema of the lungs. Autopsy results are supplemented with CT imaging and 3D reconstruction of the fractured mid face, as well as histological and toxicological examinations. This case of a misused display shell demonstrates both its devastating destructive potential and the corresponding and rarely observed injury pattern. [ABSTRACT FROM AUTHOR]

Pyrotechnic‐based firefighting systems have been found to be effective in a wide variety of firefighting applications. Binders in pyrotechnic mixtures play a significant role as they consolidate the ingredients, provide excellent mechanical strength and increase the storage life. The rise in health and environmental safety concerns in recent years has directed our research towards natural binder systems of biological origins. Therefore, in this work, galactomannan, also called guar gum, was comparatively investigated against four different types of conventional binders, phenol–formaldehyde resin, ethyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose sodium salt, which are being used in aerosol‐forming pyrotechnic mixtures for firefighting application. It was found that the nature of the binder in an amount of 3% by weight significantly influences the combustion behaviour, fire suppression performance, mechanical and thermal characteristics of gallic acid–KNO3–KClO3 tertiary aerosol‐forming pyrotechnic mixture for fire fighting application. The safety and performance characteristics of these formulations were evaluated by conducting analyses specific to pyrotechnic formulations, that is, burn rate measurement, heat of combustion, TGA/DSC thermal analysis, hygroscopic study, compression test and n‐heptane pool fire suppression test. It can be inferred from the values obtained from these analyses that guar gum is a preferred binder to the other four‐binder systems for the gallic acid–KNO3–KClO3 pyrotechnic mixture. [ABSTRACT FROM AUTHOR]

Pyrotechnics are a unique set of materials because they can be formulated to control combustion behavior to elicit desired effects such as light emission, smoke formation, and noise. The ability to enhance and control light emission is particularly desirable for entertainment purposes, as well as military applications. Designing such materials for high color purity at a specific wavelength requires an understanding of the different factors that affect their performance. This review will cover the various aspects of color production, including light emission mechanisms, components of a color composition, and key parameters that determine the optical wavelength band for these compositions. Additionally, because conventional pyrotechnic formulations are known to produce toxic emissions, less hazardous and sustainably formulated pyrotechnics for color production will also be reviewed. Finally, a short perspective is presented on the possible extension of pyrotechnic applications beyond conventional, civilian, and military purposes. [ABSTRACT FROM AUTHOR]

Fireworks that are used in our day-to-day life are also becoming a part of greenhouse emission in the environment. Hence, it becomes the need of the hour to act immediately to reduce environmental pollution so that the future becomes safer. The objective of the current research work focuses on the reduction of pollution caused due to the emission from burning fireworks and this work is intended to reduce the sulphur emissions from crackers. One of the important ingredients used in pyrotechnics is flash powder. The traditional flash powder composition contains aluminium powder as fuel, potassium nitrate as an oxidizer and sulphur as an igniter at defined levels. To reduce the impact of sulphur emissions in flash powder, an organic compound like Sargassum wightii brown seaweed powder is used as a replacement at prescribed levels and the experimentation is carried out. It is found that the sulphur weightage in the flash powder composition can be replaced up to 50% with the Sargassum wightii brown seaweed powder without affecting the traditional performance of the flash powder. To study the emissions taking place in the flash powder composition, a specially designed flash powder emission testing chamber has been developed. Three different compositions of flash powder compositions were made and they are named SP (no seaweed powder), SP5 (5% seaweed powder) and SP10 (10% seaweed powder) respectively as per the use of Sargassum wightii seaweed powder in the traditional flash powder composition. During testing, it has been found that the emission of sulphur has been reduced up to a maximum of 17% in SP% and 24% in SP10 flash powder composition. It is also evident that the flash powder composition with Sargassum wightii can result in a reduction in toxic sulphur emission by up to 21% on the modified flash powder. Furthermore, it has been found that the auto-ignition temperature of the existing and modified flash powder compositions was in the range of 353–359 °C, 357–363 °C and 361–365 °C for SP, SP5 and SP10 compositions respectively. FTIR analysis proved the presence of carbon, sulphur and nitro compounds in the Sargassum wightii seaweed powder. [ABSTRACT FROM AUTHOR]

Efficiency in the control operation of the boilers for coal and coal with biomass can be further improved if the flue gas temperature distribution can be better characterized. This is very difficult in these harsh environmental systems, where spatially resolved measurements are nearly impossible with solid‐state sensors. In this work, we evaluate the development of pyrotechnic compounds that would serve as the basis for a novel optical mapping of the temperature inside coal boilers. For this purpose, various green‐colour‐emitting pyrotechnics using BaCl2 · 2H2O and Ba(NO3)2 as the green light source were prepared, as this colour offers a distinct signal from the combustion‐based background in the boiler. These pyrotechnics were characterized using thermogravimetric analysis (TGA) and X‐ray diffraction (XRD) and tested using a flat‐flame burner. Furthermore, the composition was varied to evaluate the effect of different metal fuels such as Sn, Co, and Mg, as well as various binders such as ethylcellulose, shellac, parlon, and PVC on green light emission. The emission intensity and the apparent ignition temperature were strongly dependent on the metal type, with Mg showing higher intensities. On the other hand, the effect of the binder showed that the ignition behaviour, emission intensity, and spectral purity were influenced by the nature and exothermicity of the binder. The addition of other potential green light‐producing materials, such as boric acid, increased the intensity of emission by 17% for a BaCl2 · 2H2O‐based composition. This study identified prospective compositions with intense and bright green‐colour emissions that have high spectral purities. [ABSTRACT FROM AUTHOR]

To improve the combustion behavior of potassium perchlorate-based pyrotechnics, this study successfully prepared perovskite LaFeO3 with nitrates as raw materials using the co-precipitation method and characterized perovskite LaFeO3 through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). Moreover, it investigated the catalytic effect of LaFeO3 on the thermal decomposition of potassium perchlorate (KP) through the differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) and explored the thermal reaction behavior of pyrotechnics composed of KP and lactose. The results show that the thermal decomposition temperature of KP was 552 ​°C by adding LaFeO3, reduced by 58 ​°C. The temperature of catalytic decomposition was exactly the extrapolated onset temperature of the endothermic melting peak of KP. The addition of LaFeO3 caused the premature decomposition of the KP not yet molten, thus generating more heat in its thermal decomposition. Moreover, the addition of LaFeO3 reduced the thermal reaction peak temperature of pyrotechnics by 7 ​°C and increased the burning rate to more than two times.

A series of pyrotechnic compositions based on aromatic compounds and/or their salts in combination with pyrotechnic oxidizers possess a distinct feature: when being pressed into a tube and ignited, they burn, emitting a loud whistling noise. Such pyrotechnic effects have been known for over 100 years and are widely used for military and civil applications. The presented paper includes variable examples of pyrotechnic whistle compositions, their properties, and application examples. Additional information is provided on historical facts associated with the invention of the pyrotechnic whistles and the current state of knowledge of the whistling mechanism from both chemical and physical standpoints. [ABSTRACT FROM AUTHOR]

Smoke dyes are complex molecular systems that have the potential to form many molecular derivatives and fragments when deployed. The chemical analysis of smoke samples is challenging due to the adiabatic temperature of the pyrotechnic combustion and the molecular complexity of the physically dispersed reaction products. Presented here is the characterization of the reaction byproducts of a simulant Mk124 smoke signal on a multigram scale, which contain the dye disperse red 9 (1‐(methylamino)anthraquinone), by ambient ionization mass spectrometry. Our previous work has examined the thermal decomposition of a simplified smoke system consisting of disperse red 9, potassium chlorate, and sucrose by anaerobic pyrolysis gas chromatography mass spectrometry performed at the laboratory milligram scale. The results from the lab scale test were compared with a fully functioned Mk124 in the field. To achieve this, Mk124 smokes were functioned in the presence of sampling swabs that collected byproduct residues from the smoke plume in the ambient environment. These swabs were then analyzed using ambient ionization mass spectrometry to identify the expended pyrotechnic residues, with particular interest in halogenated species. Previous work determined the toxicity of unforeseen byproducts identified on the laboratory scale, which were also detected in the field demonstrating the correlation of the laboratory testing to the fielded systems. By understanding the chemical composition of smokes and their reaction products, potential toxicity effects can be easily assessed, leading to safer formulations with improved performance. These results can help assess how smoke byproducts may impact Warfighter performance, personnel health, and the environment. [ABSTRACT FROM AUTHOR]

As an essential component of ammunition, pyrotechnics can control ignition with high reliability. However, due to limits of fabrication technology, traditional pyrotechnics are bulky. To achieve both functionality and miniaturization, MEMS pyrotechnics integrate initiator, safety-and-arming (S&A) device and lead charge and keep all components within a small size. MEMS S&A devices, as the core component to ensure system safety, are difficult to achieve active and rapid response to control signals with high safety and reliability. In order to overcome the difficulty, we propose the design and characterization of a MEMS pyrotechnic with a double-layer barrier S&A device. The MEMS pyrotechnic is a high-integrated device with an overall size of 13.4 × 8.5 × 5.2 mm3. The initiator is a NiCr bridge foil covered with an Al/CuO energetic film, which can generate flame when ignited by an excitation voltage. To match the flame energy, lead styphnate is chosen in this study as the lead charge. The S&A device contains four semi-circular barriers, which are directly driven by V-shape electro-thermal actuators to gain active control of the pyrotechnics' ignition condition with rapid response. To improve the system's reliability, the four barriers are axisymmetrically placed in two layers, two barriers for each layer, to constitute a double-layer structure with a thickness of 100 μm. The ignition test results show that the S&A device can prevent the initiator from detonating the lead charge in safety condition. In arming condition, the lead charge will be detonated.

In this study, based on a closed bomb test combined with computational fluid dynamics, a structural finite element method, and an acoustic boundary element method, a fluid-solid acoustic one-way coupling calculation model is established for the combustion process of energetic materials in a closed bomb, and the effectiveness of the model is verified by experiments. It is found that the maximum peak sound pressure increases exponentially with an increase in loading doses or gas pressure. However, a change in the combustion coefficient of the energetic materials has little effect on the noise generated during the combustion process in the closed bomb. When the combustion coefficient is reduced by a multiple of 16, the maximum transient sound pressure is reduced by 1.79 dB, and the sound pressure level in the frequency band is reduced by 1.75 dB. With an increase in shell thickness, the combustion noise of the energetic materials in the closed bomb decreases, and the reduction range of the combustion noise increases with the increase in shell thickness.

To improve the combustion behavior of potassium perchlorate-based pyrotechnics, this study successfully prepared perovskite LaFeO3 with nitrates as raw materials using the co-precipitation method and characterized perovskite LaFeO3 through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). Moreover, it investigated the catalytic effect of LaFeO3 on the thermal decomposition of potassium perchlorate (KP) through the differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) and explored the thermal reaction behavior of pyrotechnics composed of KP and lactose. The results show that the thermal decomposition temperature of KP was 552 °C by adding LaFeO3, reduced by 58 °C. The temperature of catalytic decomposition was exactly the extrapolated onset temperature of the endothermic melting peak of KP. The addition of LaFeO3 caused the premature decomposition of the KP not yet molten, thus generating more heat in its thermal decomposition. Moreover, the addition of LaFeO3 reduced the thermal reaction peak temperature of pyrotechnics by 7 °C and increased the burning rate to more than two times. [ABSTRACT FROM AUTHOR]

To improve the infrared radiation performance of the Mg4Al3/PTFE/Viton agents (MATV), three higher energy magnesium thermite, Mg-Fe2O3, Mg-MnO2 and Mg-MoO3, were selected and added to the MATV. Thermal analysis and X-ray diffraction were used to explore the agents’ reaction processes, and infrared thermography was used to examine their combustion radiation characteristics. The results demonstrate that the thermite reaction starts after the MATV reaction and the reaction region is in the aerobic zone. All three thermites can accelerate the burning rate of MATV, and the effect is Mg-Fe2O3> Mg-MoO3> Mg-MnO2. Mg-Fe2O3 increased the infrared radiation intensity of MATV agents by 43.5% in the 2 ~ 5.5 μm band and 45.1% in the 8 ~ 14 μm band at 40% content. The effect of Mg-MoO3 on radiation area enhancement is significant, with a 107% expansion of radiation area at 70% content. The addition of thermite improves the combustion performance and radiation performance of MATV, which offers good application prospects. [ABSTRACT FROM AUTHOR]

Strong hygroscopicity will pose a huge challenge to the safety of pyrotechnic agents. In this paper, surface modification of potassium nitrate was carried out by dry modification process to prepare a new type of pyrotechnic powder with low hygroscopicity and high safety. The effect of coated potassium nitrate on pyrotechnic powder was studied: a constant temperature and humidity box was used to test the hygroscopicity, the differential thermal analysis (DTA) curve was used to estimate the ignition temperature of the sample, and drop mass and friction sensitivity tester were used to test the mechanical sensitivity of the sample. The test results suggest that the hygroscopicity of pyrotechnics is significantly reduced up to 47%, the safety is greatly improved, the pyrotechnic effect can meet the requirements for use, and other safety is improved to a certain extent. The new coating technology greatly reduces the hygroscopicity of the medicament, thereby improving the safety of pyrotechnic powder. [ABSTRACT FROM AUTHOR]

The most commonly used fast-burning composites of various compositions are reviewed. The review is based on fast-burning systems, which mainly include the compositions for retardant and special pyrautomatic devices and initiation lines, as well as nanothermites. The problem of developing gas-free (low-gas) fast-burning pyrotechnic compositions on a nanothermite basis is considered. [ABSTRACT FROM AUTHOR]

Nitrocellulose (NC) has been used since the late 1800ʹs in numerous energetic formulations; however, the effect of processing agents (solvents, etc.) on performance has not been thoroughly detailed. For illuminate applications, this is critical as spectral purity and dominant wavelength must meet specifications. In this effort, six processing agents (water, ethanol (EtOH), isopropyl alcohol (IPA), ethyl acetate (EtAc), acetone, and tetrahydrofuran (THF)) are evaluated and the effect they have on the NC fibers and subsequent performance is detailed. XRD and FTIR analysis indicates that the choice of processing agent directly affects the molecular integrity of the NC fibers due to the inhibition of NO2 bonds as well as freeing of hydrogen bonds between polymer chains during solubilization. Time-step FTIR analysis indicated that the weak nitrate ester bond (RCH2-ONO2) is targeted when processed in tetrahydrofuran, ethyl acetate, or acetone, and if heavy solvent interaction occurs, can lead to the autocatalytic decomposition of NC, when heat treated at 110°C. Spectral performance is detrimentally impacted as a result of such interactions. While all six processing agents for red-light illuminant formulations met the military requirements (i.e., spectral purity and wavelength), only ethanol and isopropyl alcohol processed formulations met the military required wavelength of 540 ± 20 nm for green-light illuminants. The IPA processed formulations exhibited the best results with spectral purity values of 69.0% and 94.8% for green and red-light illuminants, respectively. [ABSTRACT FROM AUTHOR]

Pyrotechnic-separation devices are widely used in the separation mission of satellites and projectiles. The pyroshock generated by the pyrotechnic-separation device can cause serious damage to surrounding electronic equipment owing to its high-frequency characteristics, which leads to mission failure. Therefore, solving the pyroshock problem is necessary. Typically, attenuation of the pyroshock propagation based on the understanding of the shock-propagation characteristics of a structure is possible. However, as pyrotechnics (or explosives) cannot be used for every pyroshock-propagation experiment due to the high cost and risk, a device for simulating a pyroshock environment that does not use pyrotechnics is required. In this study, a pyroshock simulator was developed, which could generate the desired shock environment by controlling shock environment-generation variables and be tested for any test structure. For this purpose, a resonator attached to the test structure and a pneumatic launch device was designed and fabricated. A resonator that generates a desired shock environment was designed by predicting the shock generation through impact analysis. A pyroshock simulator that generates a shock like an actual pyroshock was developed through comparison with the shock-response spectrum of a pyrotechnic initiator. The repeatability was verified, and the frequency and magnitude of the shock generated by the pyroshock simulator could be controlled by adjusting the collision velocity of the steel ball and the thickness of the resonator disk. [ABSTRACT FROM AUTHOR]

Considering the safety of ammunition, safety and arming (S&A) devices are usually designed in pyrotechnics to control energy transfer through a movable barrier mechanism. To achieve both intelligence and miniaturization, electrothermal actuators are used in MEMS S&A devices, which can drive the barrier to an arming position actively. However, only when the actuators' energy input is continuous can the barrier be stably kept in the arming position to wait for ignition. Here, we propose the design and characterization of a double-layer electrothermal MEMS S&A Device with a bistable mechanism. The S&A device has a double-layer structure and four groups of bistable mechanisms. Each bistable mechanism consists of two V-shape electrothermal actuators to drive a semi-circular barrier and a pawl, respectively, and control their engagement according to a specific operation sequence. Then, the barrier can be kept in the safety or the arming position without energy input. To improve the device's reliability, the four groups of bistable mechanisms are axisymmetrically placed in two layers to constitute a double-layer barrier structure. The test results show that the S&A device can use constant-voltage driving or the capacitor–discharge driving to drive the double-layer barrier to the safety or the arming position and keep it on the position passively by the bistable mechanism. [ABSTRACT FROM AUTHOR]

Sparklers offer a variety of topics for chemistry education. Redox chemistry and oxidizing agents can be found in nearly all chemistry curricula worldwide. Furthermore, environmental aspects can be shown and an insight into current research topics of pyrotechnics can be provided. The focus of the unit is the production of sparklers as a school student experiment. In addition, the effects of sparklers products on living organisms are tested in a model experiment. Finally, the conditions of producing sparklers as a school student experiment are discussed. The sparkler mixtures passed several sensitivity tests. For this reason, school students can produce the sparklers according to the current German safety guidelines in education. [ABSTRACT FROM AUTHOR]

Presented herein is an experimental study on the combustion of B4C/KNO3 binary pyrotechnic system. Combustion products were tested using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). According to the results of tests and CEA calculation, the combustion reaction equation was established. The flames and burning rates were recorded by a high speed camera and a spectrophotometer. The effect of B4C particle size on the thermal sensitivity of B4C/KNO3 was investigated by differential scanning calorimetry (DSC) techniques. In addition, a reliable method for calculating the flame temperature was proposed. Based on the results of experiments, the combustion reaction mechanism was briefly analyzed. The burning rate, flame temperature and thermal sensitivity of B4C/KNO3 increase with the decrease of B4C particle size. The mass ratio of B4C/KNO3 has a great effect on combustion properties. Oxidizer-rich compositions have low flame temperatures, low burning rates, and provide green light emission. The combustion reactions of fuel-rich compositions are vigorous, and the B4C/KNO3 with mass ratio of 25:75 has the highest burning rate and the highest flame temperature.

• The radiance and burning properties of KBF 4 was studied. • A qualitative combustion model of KBF 4 with B and KNO 3 was established. • The infrared radiation peak of B F bonds around 9 μm is of great value for spectrum regulation of spectrum-matched decoys. • The infrared absorption peak or ranges of common boron-containing substances in 1–14 μm was summarized. Increasing the selective radiation of boron-based spectral matched pyrolant in the far infrared band (8–14 μm) can make the radiation spectrum of the infrared decoy agent close to the real target. In this study, by designing B F bonds to be generated the spectral efficiency in 8–14 μm of boron-based spectrum-matched infrared decoy was improved. Potassium tetrafluoroborate (KBF 4) was used as a fluorine oxidizer in this experiment. The results show that different proportions of KBF 4 /B/KNO 3 produce characteristic radiation peaks at 5 μm and 9 μm, which are provided by boron-containing compositions. And the near, middle and far infrared color ratio of the pyrotechnic composition is about 1.4/1/0.4. By comparing with the radiation spectrum of boron-based pyrotechnics containing polytetrafluoroethylene (PTFE), it is confirmed that B F bonds can be provided from KBF 4 and emit characteristic radiation at 9 μm. Combined with TG-DTA, SEM-EDS analysis and REAL theoretical calculation results, a qualitative combustion model of KBF 4 /B/KNO 3 system, which provides infrared radiation characteristics substances (FBO, BF 3 , etc.), was established. This paper explores the potential of KBF 4 to introduce pyrotechnics as a key component of spectrum-matched infrared decoy. [ABSTRACT FROM AUTHOR]

It is very difficult to produce an intense blue colored flame using traditional fuels and blue colorants in fireworks. A new formulation of firework composition for producing an intense blue colored flame was designed in the research. In the composition, an organocopper compound was used not only as a fuel, but also as a blue colorant. Four organocopper compounds, such as copper(II) acetylacetonate, copper(II) gluconate, copper(II) benzoate, and copper(II) citrate, were chosen and tested as the candidates for fuel or blue colorant. Visible spectra of flames formed by burning the composition containing organocopper compound were measured and the hue of the flame was evaluated using the spectra. The experimental results show that the new composition consisted of the organocopper compound used as a fuel and ammonium perchlorate used as an oxidizer can produce intense blue colored flame. Especially an intense blue colored flame with approximately 60 % chromatic purity can be produced by using copper(II) acetylacetonate. The color purity is higher than that of traditional composition. The relationship between the flame behaviors and the emission spectra of the flame from burning of the new composition are examined in the study. [ABSTRACT FROM AUTHOR]

Pyrotechnic strobes have been known for over 100 years and have a wide range of uses, from the fireworks industry to military applications. On combustion, they emit bright flashes of white or colored light at regular intervals. A wide variety of fuels and oxidants can be used to create strobe compositions, but all known variants were discovered by trial and error and the mechanisms involved remain unclear. This review presents and discusses the range of known pyrotechnic strobes, together with some historical facts associated with their discovery, and comments on the current state of knowledge of the strobe mechanism. [ABSTRACT FROM AUTHOR]

When the patron saint festivities of Azkoitia, the Andramaris, were cancelled in 2020, several people asked me whether anything similar had ever happened. In this article, I describe the events that occurred during the cholera outbreak in Azkoitia in 1855 and the way in which it affected the festivities. No events took place, except for the odd religious celebration to ask for protection from San Roque. At the end of the pandemic, a Te Deum was sung at the Parish Church of Santa María La Real. The Asian morbid cholera claimed the lives of 69 residents in Azkoitia and 272 in Azpeitia. The work carried out by the town doctor of Azkoitia, Dionisio Ortiz Arrieta, and the barber or bleeder, Francisco Ignacio Sarriegui, is particularly interesting. I also discuss the publication by Doctor Juan Antonio Monedero that describes how the epidemic unfolded in Gipuzkoa. To end, I include a brief anecdote about the pyrotechnics of the time, citing the famous character of Canuto Aguirre from Vitoria. [ABSTRACT FROM AUTHOR]

Aim: The objective of the paper was to identify and analyse relevant requirements regarding the safety of storage and usage of pyrotechnic materials, intended for civil use. The review was based on binding applicable Polish and European legal acts. The results of the review pointed to the ambiguity of the provisions regulating the issues of safe usage and storage of pyrotechnical materials. Introduction: Some pyrotechnic articles, when triggered by a proper impulse, can lead to a violent reaction resulting in the release of a large amount of heat, and the creation of a blast wave. The effects of this reaction have a destructive impact on buildings situated nearby and pose a hazard to human life. Use and storage of pyrotechnic articles against the set rules is associated with the risk of fire or explosion, therefore a number of requirements have been introduced in this area. Methodology: In Poland there are many legal acts applicable to explosives. One of the most important one is the Act of 21 June 2002 on explosives designated for civil use, which presents pyrotechnic materials with respect to the safety of their usage and storage. Several key requirements have also been specified in agreements ratified in Poland and in other international acts, such as for example: the European Agreement concerning the International Carriage of Dangerous Goods by Road(ADR), and the Directive of the European Parliament and of the Council 2013/29/EU of 12 June 2013 on the harmonisation of laws of the Member States relating to the making available on the market of pyrotechnic articles. Results: It was established that there is a need of adopting a legal solution for storing pyrotechnical products for temporary sales in containers located near commercial facilities (and serving as back-up facilities). Although the regulations are not clear-cut, such a solution is used in practice, thus it would be advisable to determine by means of legal acts whether it is permissible and what requirements should be fulfilled, for example by a container, in which pyrotechnic articles are temporarily stored. Conclusions: The specification presented in the article allows to see the need to minimize the hazards associated with the marketing of pyrotechnical materials and justifies the necessity of adopting a particularly diligent classification and use of nomenclature for these products. In case of storing pyrotechnical materials, it is erroneous to adopt the determination of class “G” for two variable of net mass values of the explosive (when determining safe distances for explosive storage facilities, including among others class 1, sub-classes 1.3, 1.4). The same applies to the hexogen equivalent of an explosive load (when determining safe distances for explosive storage facilities including class 1, sub-classes 1.1, 1.5 and 4.1). Such provisions are misleading and may cause erroneous interpretations of regulations.

This article offers a micro-level examination of the firework makers in the 1675 imperial festival which took place in Edirne during the reign of Mehmed IV (r. 1648–1687). It presents a critical approach to the festival, focusing on the firework displays. This study examines overlooked dimensions of the firework displays, such as daily wages and food provisions of the firework makers, their accommodations, and inventories of the materials they used to engineer firework devices. Using eyewitness accounts, festival books, and archvial sources, it reveals previously unexamined aspects of Ottoman pyrotechnics and firework making. [ABSTRACT FROM AUTHOR]

An ammonium perchlorate (AP) and copper(II) benzoate pyrotechnic blue-flame composition was gradually "diluted" by adding an experimental perchlorate-free blue-flame composition based on aminoguanidinium nitrate (AGN), malachite, PVC powder and shellac resin. Flame's luminous intensity and specific luminous intensity were recorded and analyzed. A copper-aminoguanidinium (CuAG) complex was also synthesized and tested as an energetic additive in perchlorate-free blue-flame composition. Green-flame color was observed when testing chlorine-free energetic compositions with CuAG. [ABSTRACT FROM AUTHOR]

It is a valuable issue to explore whether a flame can radiate microwaves, in spite of the electric field formed in the flame. Presented herein is an experimental study on a series of flames with millimeter-wave radiation in the combustion of pyrotechnic films. The pyrotechnic films were composed of ultra-fine red phosphorus (P), sodium nitrate (NaNO3), Polyvinyl Alcohol (PVA) and some additives such as chopped carbon fibers (CFs) and aluminized glass fibers (GFs). The combustion temperatures and millimeter-wave radiation signals of the flames were measured, the millimeter-wave emissivity and spectral radiant exitance were calculated to describe the millimeter-wave radiation intensity. The results demonstrate that the flame of the pyrotechnic films based on P/NaNO3/CFs can radiate millimeter waves, and different materials and their proportion have a great effect on the millimeter-wave radiation intensity.

Green‐light emitting illuminant and green pearls that are currently being used for pyrotechnics are mainly composed of barium carbonate and polyvinyl chloride (PVC), which lead inevitably to the substantial generation of abundant harmful products for environmental pollution. There is thus considerable scope for the development of a novel emitting illuminant with an improved "green" composition instead of compositions incorporating barium based oxidants and polyvinyl chloride for environmental protection. For this purpose, a new composition composed of boron carbide, potassium perchlorate, and guanidine nitrate with a suitable burning rate of 5∼15 mm/s required for fireworks, the high luminous intensity of 34665 Cd and spectral purity of 67.1 % at a primary wavelength of 562 nm was developed. Notably, PM10 data demonstrated that the new composition generated less than half the amount of the smoke relative to the original one. More importantly, all of the safety parameters of this new formulation meet well with the standards' requirements, i. e., a remarkable low sensitivity to friction (0 %) and impact (8 %), relative stability to electric discharge (374.4 mJ), flame (14.0 cm) and heating (unburned, unexploded at 75 °C for 48 h), as well as a high ignition temperature of 504.0 °C and a low moisture absorption rate (0.66 %). Taken together, the new emitting illuminant developed herein showed great potential to be used for fireworks and signal flare in both military and civilian applications. [ABSTRACT FROM AUTHOR]

Tannic acid is a natural binder that was comparatively investigated against four different types of conventional synthetic binders phenol‐formaldehyde resin, carboxymethyl cellulose sodium salt, ethylcellulose, and hydroxyethylcellulose which are being used in aerosol forming pyrotechnic formulations for firefighting application. It has been found that the nature of the binder in an amount of 3 % significantly influences the fire suppression performance, thermal and mechanical characteristics of gallic acid‐based aerosol‐forming pyrotechnic mixture. The safety and performance characteristics of these formulations were evaluated by conducting analysis specific to pyrotechnic formulations, i. e., calorimetric analysis, linear solid strand burn rate measurement, TGA/DSC thermal analysis, compression test, moisture content, and fire suppression test. These formulations were designed to discharge fire extinguishing aerosol and it can be inferred from the values obtained from these analyses that tannic acid is a preferred binder to the other four binder systems for the Gallic acid‐KNO3‐KClO3 pyrotechnic mixture. [ABSTRACT FROM AUTHOR]

Pyrotechnics, which include magnesium powder, produce bright flames, but magnesium is easily aged by water. To prevent the aging problem, which decreases the burning performance and increases the risk of spontaneous combustion, it is necessary to use a stabiliser. In this study, we observed the stabilisation effect of surfactants on the aging of magnesium with ammonium perchlorate and water. The effect of sodium stearate, a straight-chain carboxylate, on the aging of magnesium with ammonium perchlorate and water, was analysed. The results showed an increase in the apparent activation energy of the exothermic reaction of magnesium when sodium stearate was used as a stabiliser. Furthermore, our experiments revealed the stabilising capability of sodium laurate, sodium behenate, and sodium dodecylbenzenesulfonate. But sodium propionate did not exhibit a pronounced stabilisation capability. The experimental results revealed that the stabilisation effect of straight-chain carboxylates increased with increasing length of their hydrocarbon chains. The relationship between the stabilisation effect and the hydrophilic-lipophilic balance was evaluated and revealed that the stabilisation effect of the surfactant on the aging of magnesium with ammonium perchlorate and water depends on its hydrophilicity. [ABSTRACT FROM AUTHOR]

Considering the safety of ammunition, safety and arming (S&A) devices are usually designed in pyrotechnics to control energy transfer through a movable barrier mechanism. To achieve both intelligence and miniaturization, electrothermal actuators are used in MEMS S&A devices, which can drive the barrier to an arming position actively. However, only when the actuators’ energy input is continuous can the barrier be stably kept in the arming position to wait for ignition. Here, we propose the design and characterization of a double-layer electrothermal MEMS S&A Device with a bistable mechanism. The S&A device has a double-layer structure and four groups of bistable mechanisms. Each bistable mechanism consists of two V-shape electrothermal actuators to drive a semi-circular barrier and a pawl, respectively, and control their engagement according to a specific operation sequence. Then, the barrier can be kept in the safety or the arming position without energy input. To improve the device’s reliability, the four groups of bistable mechanisms are axisymmetrically placed in two layers to constitute a double-layer barrier structure. The test results show that the S&A device can use constant-voltage driving or the capacitor–discharge driving to drive the double-layer barrier to the safety or the arming position and keep it on the position passively by the bistable mechanism.

Pyrotechnic-separation devices are widely used in the separation mission of satellites and projectiles. The pyroshock generated by the pyrotechnic-separation device can cause serious damage to surrounding electronic equipment owing to its high-frequency characteristics, which leads to mission failure. Therefore, solving the pyroshock problem is necessary. Typically, attenuation of the pyroshock propagation based on the understanding of the shock-propagation characteristics of a structure is possible. However, as pyrotechnics (or explosives) cannot be used for every pyroshock-propagation experiment due to the high cost and risk, a device for simulating a pyroshock environment that does not use pyrotechnics is required. In this study, a pyroshock simulator was developed, which could generate the desired shock environment by controlling shock environment-generation variables and be tested for any test structure. For this purpose, a resonator attached to the test structure and a pneumatic launch device was designed and fabricated. A resonator that generates a desired shock environment was designed by predicting the shock generation through impact analysis. A pyroshock simulator that generates a shock like an actual pyroshock was developed through comparison with the shock-response spectrum of a pyrotechnic initiator. The repeatability was verified, and the frequency and magnitude of the shock generated by the pyroshock simulator could be controlled by adjusting the collision velocity of the steel ball and the thickness of the resonator disk.

The measurement of particulate matter (TSP, PM10, and PM2.5) emitted by pyrotechnic articles is described. For this purpose, pyrotechnic articles for entertainment purposes of category F2 (i. e. consumer fireworks according to European legislation) are examined exemplarily. The aim was to determine reliable emission factors (EF). Different types of pyrotechnic articles were used to obtain a more representative database. Commonly used analytical methods, like impactor technology, are accompanied by scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy to obtain a better insight into the nature of the emissions. Specific emission factors are determined for each pyrotechnic article. In the absence of activity rates, an average specific emission factor can be used to assess emission inventories. The average emission factors for investigated articles are 253 g PM10 per kg net explosive content (NEC) and 200 g PM2.5 per kg NEC. The highest emission is found for a battery of shot tubes, the lowest emission of particulate matter is found for a fountain‐like pyrotechnic article. Furthermore, the hypothesis is assessed whether it makes a difference to determine emission data based on pyrotechnic mixtures or pyrotechnic articles. It is demonstrated that the combustion of pyrotechnic articles generates a higher amount of particulate matter than the combustion of pyrotechnic mixtures. [ABSTRACT FROM AUTHOR]

This article summarises the development of chemical composition of European fireworks mixtures in the seventeenth, eighteenth and in the beginning of the nineteenth century. The attention is especially paid to individual colouring agents which were used to colour the flame of a fireworks mixture. For the colouring agents, physical-chemical principles responsible for the resulting colour of the flame were explained on the basis of the knowledge of modern chemistry and pyrotechnics. [ABSTRACT FROM AUTHOR]

Creating next-generation pyrotechnic emitters capable of dynamically controllable light output requires a paradigm shift away from emission control via formulation. This work demonstrates the ability to modulate light emission intensity of a pyrotechnic flame with 2.46 GHz microwave energy within a multimodal cavity. Stoichiometric mixtures of three pyrotechnic systems are investigated: magnesium fuel with oxidizers of NaNO 3 , KNO 3 , or CsNO 3. Using time-resolved visible and infrared emission spectroscopy and high-speed color videography, microwave illumination of flames is found to produce enhanced atomic photo emission from the alkali species. Emission increases of up to ~120% are demonstrated, which are predominantly in the visible and near-infrared wavelengths and have little effect on flame emission chromaticity. At near- and mid-IR wavelengths, gray body continuum enhancement is observed with moderate enhanced emission from CO 2 and H 2 O bands. Sustained light emission from microwave illumination of combustion products long after pyrotechnic extinguishment was also demonstrated. A simplified model of microwave-enhanced visible and near-IR emission is presented and shown to be consistent with the observed trend of elevated emission enhancement for lower wavelength alkali transitions. Sensitivity analysis is performed which suggests a lower equilibrium population of electronically excited alkali atoms is primarily responsible for maximizing the degree of light emission enhancement of applied microwave fields, especially in extinguished low-temperature pyrotechnic plumes. These findings suggest microwave illumination of alkali-containing pyrotechnic flames may be a useful strategy to achieve dynamic control of light emission intensity. [ABSTRACT FROM AUTHOR]