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نتیجه جستجو - مواد منفجره

تعداد مقالات یافته شده: 8
ردیف عنوان نوع
1 Identification and differentiation of commercial and military explosives via high performance liquid chromatography – high resolution mass spectrometry (HPLC-HRMS), X-ray diffractometry (XRD) and X-ray fluorescence spectroscopy (XRF): Towards a forensic substance database on explosives
شناسایی و تمایز مواد منفجره تجاری و نظامی از طریق کروماتوگرافی مایع با کارایی بالا - طیف سنجی جرمی با وضوح بالا (HPLC-HRMS) ، پراش سنجی اشعه ایکس (XRD) و طیف سنجی فلورسانس اشعه ایکس (XRF): به سمت پایگاه داده مواد پزشکی قانونی در مورد مواد منفجره-2020
The identification of confiscated commercial and military explosives is a crucial step not only in the uncovering of distribution pathways, but it also aids investigating officers in criminal casework. Even though commercial and military explosives mainly rely on a small number of high-energy compounds, a great variety of additives and synthesis by-products can be found that can differ depending on the brand, manufacturer and application. This makes the identification of commercial and military explosives based on their overall composition a promising approach that can be used to establish a pan-European Forensic Substance Database on Explosives. In this work, three analytical techniques were employed to analyze 36 samples of commercial and military explosives from Germany and Switzerland. An HPLC-HRMS method was developed, using 27 analytes of interest that encompass high-energy compounds, synthesis by-products and additives. HPLCHRMS and XRD were used to gather and confirm molecular information on each sample and XRF analyses were carried out to gain insight on the elemental composition. Combining the results from all three techniques, 41 different additives could be identified as being diagnostic analytes and all samples showed a unique analytical fingerprint, which allows for a differentiation of the samples. Therefore, this work presents a set of methods that can be used as a foundation for the creation and population of a database on explosives that enables the assigning of specific formulations to certain brands, manufacturers and countries of origin.
Keywords: HPLC-HRMS | Powder XRD | XRF | Explosives | Commercial explosives | Military explosives
مقاله انگلیسی
2 A pressure- or velocity-dependent acceleration rate law for the shock-to-detonation transition process in PBX 9502 high explosive
قانون میزان شتاب فشار یا وابسته به سرعت برای روند انتقال شوک به انفجار در مواد منفجره PBX 9502-2020
Shock-to-detonation transition profiles of PBX 9502 explosive are analyzed to develop a rate law for shock acceleration. The shock motion profiles are seen to follow a common trend in the shock acceleration–velocity frame, aside from an early time transient that is dependent on the initiating shock strength. The duration of the early time transient is seen to correlate with the initial shock strength. The com- mon shock acceleration profile is seen to be Arrhenius-like with respect to the local particle velocity or pressure. A dual-rate pressure-dependent Arrhenius-type rate law is developed with the duration of the early rate set by the initial shock strength. The rate law is able to predict the shock motion for all tests well in both particle velocity and pressure space. In addition to directly measuring commonalities in the acceleration profiles of the experimental shock motion, this work provides insight into the functional form of the reaction rate laws for this TATB-based high explosive. The rate law also supports the concept that shock-driven reaction in heterogenous high explosives is driven by localized ignition and growth of hotspots.
Keywords: Detonation | Shock-to-detonation | transition SDT | Detonation reaction rate | High explosive
مقاله انگلیسی
3 Light trapping induced flexible wrinkled nanocone SERS substrate for highly sensitive explosive detection
بستر SERS nanocone چین خورده انعطاف پذیر ناشی از به دام انداختن نور برای تشخیص مواد منفجره بسیار حساس-2020
We reported an ultrasensitive TNT detection method via a novel light trapping induced wrinkled nanocone flexible SERS substrate, which was fabricated by colloidal lithography and oxygen plasma etching on transparent PET film. Especially, a set of nanowrinkles with 50−60 nm was found on the sidewall of nanocone after etching. By coating 30 nm gold film, this flexible SERS substrate provided uniform hot spots, which demonstrated high reproducibility and sensitivity. 4-ATP molecules based Meisenheimer complex, which is a well-known chargetransfer interaction between electron-poor TNT and electron-rich amino group, was taken to detect ultra-low concentration of TNT explosive. The Raman signal of TNT was significantly enhanced by charge-transfer, light trapping effect and coupled electromagnetic field. The detection sensitivity of TNT molecules was as low as 10−13mol/L, and show a good linear response in the range from 10−8 to 10−13mol/L. Consequently, by brushing this flexible SERS substrate onto a cloth bag, trace amount of TNT residues with concentration as low as 10-10mol/L can be easily analyzed. It is believed that the proposed highly sensitive and uniform flexible substrate provides a significant solution for trace analysis of TNT residue in criminal forensic, military and security check.
Keywords: Nanocone | Nanowrinkle | Flexible materials | Light trapping | SERS
مقاله انگلیسی
4 Analysis of samples of explosives excavated from the Baltic Sea floor
تجزیه و تحلیل نمونه های مواد منفجره کشف شده از کف دریای بالتیک-2020
After World War II, conventional and chemical ammunition containing mainly secondary and primary explosives was dumped in the sea. Explosives have medium toxicity to aquatic organisms, earthworms and indigenous soil microorganisms. Therefore, environmental monitoring is required, especially for dumped munitions. The main aspect of this work was to analyse the samples of lumps and sediments taken from the Baltic seabed. These samples were potentially explosives. The main goal of the study was to identify the type and composition of studied materials. In order to determine the chemical composition of samples of explosives, we used as follows: GC–MS/MS, LC-HRMS and NMR. Additionally, to determine the energetic properties we performed microcalorimetric-thermogravimetric analysis. Based on the obtained results, the composition of this explosive was TNT (41%), RDX (53%), aluminium powder (5%), and degradation products (below 1%). The resulting composition indicates that the analysed material can be classified in the ‘‘torpex” family, widely used during World War II. Regarding the results of the microcalorimetric analysis, we can conclude that excavated fragments of explosives are in very good condition and they still can detonate after being initiated. Therefore, there is a threat that they could be used for criminal or terrorist purposes.
Keywords: Environmental samples | Explosives and their degradation products | Chromatographic analysis | Mass spectrometry | Nuclear magnetic resonance spectroscopy
مقاله انگلیسی
5 Design of fluorescent sensors based on azaheterocyclic push-pull systems towards nitroaromatic explosives and related compounds: A review
طراحی سنسورهای فلورسنت مبتنی بر سیستمهای فشار کششی azaheterocyclic به سمت مواد منفجره نیتروارماتیک و ترکیبات مرتبط: بررسی-2020
Highly sensitive and selective detection of nitro containing high energy organic compounds such as picric acid (PA), 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) has become a challenging task due to concerns over national security, criminal investigations and environment protections. Among various known detection methods, fluorescence sensors have gained special attention in recent time. The family of fluorescent sensors based on push-pull systems that incorporate nitrogen heterocycles as an electron-withdrawing group have a growing interest due to their high sensitivity, selectivity and easy tuning. The fluorescent sensors discussed in this review are classified and organized according to used azaheterocyclic scaffold, their functionality and their ability to detect of nitroaromatics by fluorescence quenching.
Keywords: Nitroaromatic explosives | Fluorescence quenching | Pyridines | Pyrimidines | Pyrazines | Triazines
مقاله انگلیسی
6 Study on the propagation law of gas explosion in the space based on the goaf characteristic of coal mine
مطالعه قانون انتشار انفجار گاز در فضا براساس ویژگی گواف معدن ذغال سنگ-2020
Gas explosions causing heavy casualties in the goaf of coal mine occasionally occurred in China. The goaf in the coal mine is a multi-scale complex medium with pores in remaining coal, the gaps among rock blocks that don’t meet the characteristics of the porous medium. The propagation of flames and shock waves induced by the gas explosion in the goaf is very complicated. Based on the spatial structure characteristics of the goaf, the numerical model of a gas explosion is established by using the OpenFOAM open-source CFD source code. The flame and shock wave propagation characteristics induced by the gas explosion are analyzed under the conditions of different arrangements for gradient diameter rocks. The results reveal that the initial flame propagation speed, shock wave and the pressure rise speed all increases firstly, while the values show a decreasing trend when the diameter of the rocks increases in the gradient rocks diameter model. The research results will be of great guiding significance for the prevention and control of gas explosions in the goaf, and the investigation of gas explosion accidents.
Keywords: OpenFOAM | The goaf in the coal mine | Gas explosive | Shock wave
مقاله انگلیسی
7 Effects of ignition energy on fire and explosion characteristics of dilute hybrid fuel in ventilation air methane
اثر انرژی اشتعال در آتش سوزی و ویژگی های انفجار سوخت ترکیبی رقیق در تهویه متان هوا-2016
Deflagration explosions of coal dust clouds and flammable gases are a major safety concern in coal mining industry. Accidental fire and explosion caused by coal dust cloud can impose substantial losses and damages to people and properties in underground coal mines. Hybrid mixtures of methane and coal dust have the potential to reduce the minimum activation energy of a combustion reaction. In this study the Minimum Explosion Concentration (MEC), Over Pressure Rise (OPR), deflagration index for gas and dust hybrid mixtures (Kst) and explosive region of hybrid fuel mixtures present in Ventilation Air Methane (VAM) were investigated. Experiments were carried out according to the ASTM E1226-12 guideline utilising a 20 L spherical shape apparatus specifically designed for this purpose.Results: obtained from this study have shown that the presence of methane significantly affects explo- sion characteristics of coal dust clouds. Dilute concentrations of methane, 0.75e1.25%, resulted in coal dust clouds OPR increasing from 0.3 bar to 2.2 bar and boosting the Kst value from 10 bar m s—1 to 25 bar m s—1. The explosion characteristics were also affected by the ignitors’ energy; for instance, for a coal dust cloud concentration of 50 g m—3 the OPR recorded was 0.09 bar when a 1 kJ chemical ignitor was used, while, 0.75 bar (OPR) was recorded when a 10 kJ chemical ignitor was used.For the first time, new explosion regions were identified for diluted methane-coal dust cloud mixtures when using 1, 5 and 10 kJ ignitors. Finally, the Le-Chatelier mixing rule was modified to predict the lower explosion limit of methane-coal dust cloud hybrid mixtures considering the energy of the ignitors.© 2015 Elsevier Ltd. All rights reserved.
Keywords: Hybrid mixture | Deflagration index | Pressure rise | Explosion characteristics | ASTM E2021 | Coal dust | Methane | Explosion | Dust cloud
مقاله انگلیسی
8 نفوذ مکرر و انفجار در اعماق مختلف بتن با عملکرد فوق العاده قوی
سال انتشار: 2015 - تعداد صفحات فایل pdf انگلیسی: 12 - تعداد صفحات فایل doc فارسی: 32
بتن با عملکرد فوق العاده قوی (UHPC) تهیه شده و رفتار دینامیکی آن تحت نفوذ مکرر و انفجارهای عمقی مختلف با استفاده از گلوله های 14.5 میلیمتری و مواد منفجره TNT مورد بررسی و تحقیق قرار گرفت. عمق نفوذ UHPC در تعداد نفوذهای مختلفی اندازه گیری شد. آسیب UHPC با روش سرعت موج فراصوت اندازه گیری شد و فرآیند نفوذ UHPC با دوربین پرسرعت مورد مشاهده قرار گرفت. آسیب انفجاری UHPC با مواد منفجره TNT مدفون شده در اعماق مختلف اندازه گیری شد و فرآیند انفجار با روش المان محدود شبیه سازی گردید. نتایج نشان می دهند که مقاومت بتن UHPC در برابر نفود مکرر و انفجارهای عمقی مختلف به وسیله آرماتورگذاری ترکیبی فولاد و الیافت بازالت بطور چشمگیری بهبود می یابد. عمق نفوذ ثانویه این بتن با مصالح درشت دانه بازالت کاهش می یابد و آسیب بتن با مصالح درشت دانه بازالت بیشتر از آسیب این بتن بدون مصالح درشت دانه بازالت است. جرم و عمق جاگذاری مواد منفجره اثرات مهمی بر آسیب بتن UHPC دارد.
کلمات کلیدی: بتن با عملکرد فوق العاده بالا | نفوذ | انفجار | خسارت | المان محدود
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