共查询到20条相似文献,搜索用时 15 毫秒
1.
The application of single-particle aerosol mass spectrometry (SPAMS) to the real-time detection of micrometer-sized single particles of high explosives is described. Dual-polarity time-of-flight mass spectra from 1000 single particles each of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN), as well as those of complex explosives, Composition B, Semtex 1A, and Semtex 1H, were obtained over a range of desorption/ionization laser fluences between 0.50 and 8.01 nJ/microm2. Mass spectral variability with laser fluence for each explosive is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle ( approximately 1 pg) without the need for consumables is demonstrated. 相似文献
2.
The identification of explosives and their degradation products is important in forensic and environmental applications. Complete separation of these structurally similar compounds using reversed-phase liquid chromatography has proven to be a challenge. Here we present a demonstration of the use of capillary electrochromatography on the separation of a series of 14 nitroaromatic and nitramine explosive compounds. A separation with baseline resolution is achieved for all of the compounds in under 7 min, featuring efficiencies of over 500?000 theoretical plates/m. Using more aggressive running conditions, 13 of the 14 compounds are separated in under 2 min. 相似文献
3.
Due to the large number and distribution of asteroids and comets in the solar system, there is the distinct possibility of one of them striking Earth just as comet Shoemaker-Levy 9 struck Jupiter. A debate is ongoing in the scientific community as to how best to divert such a threat. In 2005 NASA was directed by Congress to provide a report on the detection of near-Earth objects (NEOs) and their mitigation if determined to be a threat. The report was delivered in March 2007; as input to that report, the work reported here provided information on conventional methods to divert a potentially hazardous object (PHO) including conventional explosives and direct impact with a rocket. Other slow push conventional approaches include propulsion systems attached to the asteroid or comet and the recently proposed gravitational tractor. Advantages of conventional explosives are that they can be delivered in small packages so that the asteroid or comet is in no danger of being broken up and it is possible to accurately compute the momentum transferred to the asteroid or comet through modern validated numerical techniques. This work demonstrates that conventional explosives can be an efficient conventional method to divert an asteroid or comet and computes the amounts of explosives needed. 相似文献
4.
Keshavarz MH 《Journal of hazardous materials》2006,137(3):1303-1308
A new scheme is introduced for calculating detonation temperature of different classes of high explosives. The ratio of oxygen to carbon and hydrogen to oxygen as well as specific structural parameters are the fundamental factors in the new method. An empirical new correlation is used to calculate detonation temperature of energetic compounds without considering heat contents of explosives and detonation products. Calculated detonation temperatures for both pure and explosive formulations show good agreement with respect to measured detonation temperatures and complicated computer code using BKWR and BKWS equations of state. Predicted detonation temperatures have root-mean-square (rms) percent deviation of 4.6, 14.2 and 4.6 from measured values for new method, BKWR and BKWS equations of state, respectively. 相似文献
5.
Richard A. Hildner 《Journal of hazardous materials》1977,2(2):183-187
Samples of high explosives for environmental testing have been successfully enclosed in all-welded assemblies. Proper container design, fixturing, welding power supply, and welding parameters ensure the safe, timely completion of the task. 相似文献
6.
Journal of Materials Science - 相似文献
7.
8.
为了提高含能射孔弹综合性能,降低致密油气储层的开采难度,对装填RL-F含铝炸药射孔弹的性能进行了研究。首先以RL-F含铝炸药为研究对象,对RL-F含铝炸药进行了机械感度、静电火花感度、5 s延滞期爆发点和DSC热分解测试;其次分别将RL-F含铝炸药和JH-16炸药装填在89型射孔弹中,进行了地面模拟装枪穿钢靶和穿柱状混凝土靶试验。结果显示:RL-F含铝炸药具有合适的机械感度,耐热性良好,适用于射孔弹压装工艺;与装填JH-16炸药的89型射孔弹穿深性能相比,装填RL-F含铝炸药的89型射孔弹地面侵彻钢靶和地面侵彻柱状混凝土靶穿深分别降低了10.6%和27.5%,而装填RL-F炸药在侵彻混凝土靶时射流孔道干净清晰、无杵堵,孔道无压实带。 相似文献
9.
10.
M. L. Sandoval M. H. Talou A. G. Tomba Martinez M. A. Camerucci 《Journal of Materials Science》2010,45(18):5109-5117
In this study, the high temperature mechanical behavior of cordierite porous disks prepared by the starch consolidation forming
method was evaluated. In this method, due to the swelling and gelatinization properties of starch in aqueous suspension at
a temperature between 55 and 85 °C, the starch granules perform as both consolidator/binder of the green body and pore former
at high temperature. Aqueous suspensions (29.6 vol.%) of a cordierite precursor mixture (talc, kaolin, and alumina) with the
addition of potato or cassava starches (11.5 vol.%) were prepared by intensive mechanical mixing, homogenization, and vacuum
degasification. Green disks were formed by thermogelling of the aqueous suspensions at 85 °C for 4 h followed by additional
drying at 50 °C for 24 h. They were characterized by bulk density and apparent porosity measurements, and microstructural
analysis by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Porous cordierite materials
were obtained by calcination at 650 °C for 2 h and reaction-sintering at 1330 °C for 4 h, employing specific, controlled heating
schedules in both treatments. Cordierite disks were characterized by bulk density and apparent porosity measurements, and
microstructural analysis by SEM. Mechanical behavior was evaluated in diametral compression using a servohydraulic testing
machine at room temperature (RT), 800, 1000, and 1100 °C. Apparent stress–strain relationships were obtained from load–displacement curves, and mechanical
parameters, such as fracture strength (σF), apparent Young modulus (E
a), and yield stress (σY), were determined. Moreover, crack patterns were also evaluated. The obtained results were analyzed in function of the developed
microstructures, considering the presence of a silicate glassy phase and a complex porosity, and the testing temperature. 相似文献
11.
12.
We present a Raman spectroscopic method for the noninvasive detection of liquid explosives within bottles, and other packaging, of substantially higher sensitivity and wider applicability than that currently available via conventional Raman spectroscopy. The approach uses a modification of the spatially offset Raman spectroscopy (SORS) concept, which permits the interrogation of a wide range of containers, including transparent, colored, and diffusely scattering plastic and glass beverage, medicine, and cosmetic bottles, with no change in experimental geometry. The enhanced sensitivity is achieved by the technique's inherent ability to effectively suppress fluorescence and Raman contributions originating from the wall of the container. The application is demonstrated on the noninvasive detection of hydrogen peroxide solution, a critical component of a number of liquid explosives. In contrast to conventional Raman spectroscopy, the modified SORS concept enables the detection of concealed hydrogen peroxide solution in all the studied cases. 相似文献
13.
Bauer F 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(6):1448-1454
Ferroelectric polymers (PVDF) with well-defined and precisely known electrical properties are now routinely available from commercial sources. Electrical processing with the Bauer cyclic poling method can produce individual films with well-defined remanent polarization up to 9 /spl mu/C/cm/sup 2/. These polymers provide an unusual opportunity to study the structure and physical properties of materials subjected to shock loading. The behavior of PVDF has been studied over a wide range of pressures using high-pressure shock loading and has yielded well-behaved, reproducible data up to 25 GPa in inert materials. The application of PVDF gauges for recording shock waves induced in polar materials such as Kel-F, PMMA, or in reactive materials is hampered by observations of anomalous responses due to shock-induced polarization or an electrical charge released inside a shock-compressed explosive. A solution using an appropriate electrical shielding has been identified and applied to PVDF for shock measurement studies of Kel-F, and for Hugoniot measurements of high explosives (PH). Furthermore, shock pressure profiles obtained with in situ PVDF gauges in porous HE (Formex) in a detonation regime have been achieved. Typical results of shock pressure profile versus time show a fast superpressure of a few nanoseconds followed by a pressure release down to a plateau level and then by a pressure decay. More accurate measurements are reported with electrically improved PVDF gauges as well as with 0.25 mm/sup 2/ active area PVDF gauges. 相似文献
14.
15.
Roscioli KM Davis E Siems WF Mariano A Su W Guharay SK Hill HH 《Analytical chemistry》2011,83(15):5965-5971
Ion mobility spectrometry (IMS) has become the most widely used technology for trace explosives detection. A key task in designing IMS systems is to balance the explosives detection performance with size, weight, cost, and safety of the instrument. Commercial instruments are, by and large, equipped with radioactive (63)Ni ionization sources which pose inherent problems for transportation, safety, and waste disposal regulation. An alternative to a radioactive source is a corona discharge ionization source, which offers the benefits of simplicity, stability, and sensitivity without the regulatory problems. An IMS system was designed and built based on modeling and simulation with the goal to achieve a lightweight modular design that offered high performance for the detection of trace explosives using a corona ionization source. Modeling and simulations were used to investigate design alternatives and optimize parameters. Simulated spectra were obtained for 2,4,6-trinitrotoluene (TNT) and cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) and showed good agreement with experimentally measured spectra using a corona ionization source. The reduced mobilities for TNT and RDX obtained with corona ionization were 1.53 and 1.46 cm(2)/(V s), respectively, and this agreed well with literature values. 相似文献
16.
Saikku-Bäckström A Tulamo RM Pohjonen T Törmälä P Räihä JE Rokkanen P 《Journal of materials science. Materials in medicine》1999,10(1):1-8
A study was carried out to investigate changes in mechanical properties and degradation of self-reinforced fibrillated poly-96L/4D-lactide (SR-PLA96) rods in vitro and in vivo. The viscosity-average molecular weight, Mv, of the intact sterile (gamma irradiated) rods was around 50 000 g mol-1. The SR-PLA96 rods of diameter 1.1 mm by 30 mm and diameter 4.5 mm by 50 mm were immersed in phosphate-buffered saline or implanted in the dorsal subcutis of rabbits. Bending, shear and torsion strength and bending modulus, together with the changes of viscosity and crystallinity, were measured up to 24 wk. The strength values showed only a slight decrease during the follow-up period with the exception of torsion strength, that decreased to 52% of the initial value during 24 wk. There were no statistically significant differences in the strength retention between in vitro and in vivo groups. Crystallinity increased over time, being 46–49% at 24 wk. The Mv of the rods decreased over 50% by 24 wk. These promising results motivated us to continue the studies with the fixation of experimental cortical bone osteotomies with SR-PLA96 intramedullary rods. © 1999 Kluwer Academic Publishers 相似文献
17.
18.
19.