Variation of Methods in Small‐Scale Safety and Thermal Testing of Improvised Explosives

One of the first steps in establishing safe handling procedures for explosives is small‐scale safety and thermal (SSST) testing. To better understand the response of homemade or improvised explosives (HMEs) to SSST testing, 16 HME materials were compared to three standard military explosives in a proficiency‐type round robin study among five laboratories, two U.S. Department of Defense and three U.S. Department of Energy, sponsored by the Department of Homeland Security, Science & Technology Directorate, Explosives Division. The testing included impact, friction, electrostatic discharge (ESD) and thermal. The testing matrix was designed to address problems encountered with improvised materials: powder mixtures, liquid suspensions, partially wetted solids, immiscible liquids, and reactive materials. All testing materials and/or precursors came from the same batch distributed to each of the participants and were handled, pretreated, and mixed by standardized procedures. For this proficiency test, the participants had similar equipment, usually differing by vintage. This allowed for a direct comparison of the results from each participant to the average of the results from all the participants. Some general trends observed for each series of tests were: (1) Drop hammer – LLNL usually found the materials less sensitive than the average with materials that have high sensitivity to impact and LANL usually found the materials less sensitive than the average with materials that have high sensitivity to impact; (2) friction – LLNL found the materials less sensitive than the average; (3) and ESD – IHD usually found the materials less sensitive than the average. In this report, the proficiency test data from all the participants is compared and contrasted for impact, selected friction, and ESD testing. Other friction and thermal data will be addressed elsewhere as well as the statistical analysis of several repeated measurements on the proficiency test standards.     

爱立信3G视线系列二移动营销的兴起

在日本,移动数据业务推出后,消费行业迅速地开发其应用,然而即使采用了各种改善方法,许多日本商人经常在问这样一个问题:“我怎样才能利用移动数据的蓬勃发展来改进我的生意?”目前,手机和移动运营商的网络已经能够被用来作为直接向消费者传播营销和宣传材料的渠道。起初,随意向手机发送营销资料的现象比较严重,垃圾信息大量涌现,这是一个令人十分讨厌的现象。后来,人们逐渐意识到经过许可的营销才更有效,如一个用户也许会有一种特别的爱好(如音乐)并为此签订了相关业务,如果有相关新产品发布,他将能够获得一定的折扣。各种形式的移动营销对…     

The residual lifetime of creepdeformed material: Microstructural changes occurring during creep of a 12%CrMoVW steel

The microstructure of specimens of a 12%CrMoVW steel which were creep tested at 500—650°C for 8000—43 000 h has been investigated. The basic microstructure consisted of tempered martensite and about 1% of δ-ferrite. The fine precipitates ( <0.1 J,Lm) found in both phases coarsened only slowly with increasing ageing temperature and time. Coarser carbides (> 0.2 μ,Lm) in the tempered martensite grew up to five times their original size during ageing. The precipitates are probably mainly M₂₃C₆. The size of these carbides, as well as those in the previous austenite grain boundaries, could be related to the Larson—Miller temperature—time parameter corresponding to the ageing.     

Creep damage in welded joints of 0.5CrMoV steel

The creep damage in two components along a main steam pipe in a fossil-fired power plant has been investigated using plastic replicas. Extensive damage in the weldedjoints was found in both components including several macrocracks. Out of eight analysedjoints, five showed significant damage. All stages of damage from single cavities to macrocracks were present. At a number of positions around thejoints damage was observed in the weld metal, the heat affected zone and the parent metal. For comparison cavitation was also examined in crossweld specimens from creep tests. Characteristic features of the cavitation in power plant were reproduced. In the heat affected zone adjacent to the parent metal a high density of separate cavities was observed. In the coarse grained part of the heat affected zone rows ofcavities were present in some grain boundaries.     

Estradiol modulation of the speed of an internal clock.

Estradiol significantly influences dopamine (DA) activity in the striatum (e.g., J. B. Becker, 1990b), and researchers have strongly implicated striatal DA in the regulation of temporal integration in the seconds-to-minutes range (e.g., W. H. Meck, 1996). In the current experiment, the author examines the effect of acute estradiol administered prior to testing on a peak-interval (PI) timing task. The administration of 5 μg of estradiol 30 min prior to testing resulted in an immediate and proportional leftward shift in the timing functions relative to the PI functions obtained following the administration of the oil vehicle. The precision of the response functions was increased in a manner commensurate with the scalar property of interval timing without significant alteration of peak response rates. When timing behavior was assessed 3 days following estradiol or oil administration, no differences were found in the peak time of responding or in the precision of responding between estradiol- and oil-treated rats, indicating that the effects of estradiol on these measures of interval timing are short lived. Together, these findings indicate that estradiol selectively increases the speed of an internal clock, perhaps through facilitating striatal DA activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Statistical Analysis of an Inter‐Laboratory Comparison of Small‐Scale Safety and Thermal Testing of RDX

The Integrated Data Collection Analysis (IDCA) program has conducted a proficiency test for small‐scale safety and thermal (SSST) testing of homemade explosives (HMEs). Described here are statistical analyses of the results from this test for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of the RDX Class 5 Type II standard. The material was tested as a well‐characterized standard several times during the proficiency test to assess differences among participants and the range of results that may arise for well‐behaved explosive materials. The analyses show there are detectable differences among the results from IDCA participants. While these differences are statistically significant, most of them can be justified for comparison purposes to assess potential variability when laboratories attempt to measure identical samples using methods assumed to be nominally the same. The results presented in this report include the average sensitivity results from the IDCA participants and the ranges of values obtained. The ranges represent variation about the mean values of the tests of between 26 % and 42 %. The magnitude of this variation is attributed to differences in operator, method, and environment as well as the use of different instruments that are also of varying age. The results appear to be a good representation of results generated by the broader safety testing community based on the range of methods, instruments, and environments included in the IDCA proficiency test.     

Process–Structure Map for Diamond‐Like Carbon Fibers from Ethene at Hyperbaric Pressures

High‐pressure laser chemical vapor deposition (HP‐LCVD) is a powerful tool for growing complex microstructures at rapid rates. Not only is it possible to deposit functionally graded materials, but new metastable phases, alloys, and composite materials may be realized. In this paper, the diversity of microstructures that may be obtained through HP‐LCVD is demonstrated, including the growth of metastable materials, e.g., diamond‐like carbon (DLC). For the first time, a pressure–temperature (P–T) phase diagram has been created for HP‐LCVD, identifying nine distinct material phases of carbon from ethene. Regions of high sp³ content are identified via Raman spectroscopy. The kinetics, rate limitations, and thermodynamics of the process are also characterized at hyperbaric pressures, creating a first‐ever process‐rate map—covering the entire useful pressure range for ethene. Thermodynamically enhanced growth is also documented for the first time, where the contribution of the heat of reaction is much greater than the incident laser power—demonstrating a quasi‐self‐sustaining reaction. Finally, sufficient information is provided to reconstruct specific fiber geometries, structures, and growth rates for potential industrial production of carbon fibers from the gas phase.     

Study of Ti in solvent-refined coal by X-ray absorption spectroscopy

The chemical environment of titanium in solvent-refined coal (SRC-I and SRC-II) has been studied using X-ray absorption spectroscopy. Evidence that organic complexes of Ti are produced in the liquefaction process from mineral forms of Ti present in the feed coal is presented, based on the pre-edge structure of the X-ray absorption spectra.