Wyniki wyszukiwania - BazTech

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Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity

Peng Q., Cao W., Zhou W., He Z., Jiang W., Chen W.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 3

755--769

EN

The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.

2

Crash safety of a typical bay table in a railway vehicle

Matsika E., Peng Q.

Transport Problems

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2015

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T. 10, z. spec.

97--110

EN

Increasingly, urban and high speed trains are incorporating tables (workstations) as common railway vehicle interior furniture because passengers prefer seating by bay tables. Among table design characteristics, the most challenging is meeting crashworthiness requirements. Past accident data and sled test results have shown that in the event of railway vehicle frontal impact, occupants located in the bay seating are exposed to chest and abdominal injuries upon contact with tables resulting from secondary collision. In some cases tables have tended to be structurally weak; they easily detach from the side walls and/or floor mounting. Subsequently these become unguided missiles that strike occupants, resulting in injuries. This paper presents an analysis of the crash performance of a typical bay table. The results provide some understanding of the table’s crash safety, giving an indication of its impact aggression. Table materials are characterised using quasi-static compressive tests. In addition, experimental dynamic (impact) tests are conducted using a pendulum representing a body block (mass). The results provide information about the possible loading of the table on the occupant in the event of a crash. Contact forces are compared with chest and abdominal injury tolerance thresholds to infer the collision injury potential. Recommendations are then made on design of bay tables to meet the “functional-strength-and-safety balance”.

PL

Coraz częściej zarówno w pociągach miejskich, jak i pociągach dużych prędkości wprowadza się do wyposażenia stoły. Wynika to z wymagań pasażerów, którzy to preferują siedzenie przy stołach. Wśród cech konstrukcyjnych stołów, największym wyzwaniem jest spełnienie wymagań wytrzymałości zderzeniowej. Wcześniejsze informacje dotyczące wypadków i wyniki badań wykazały, że w przypadku czołowego zderzenia pojazdów kolejowych pasażerowie, znajdujący się w sąsiedztwie stołów, są narażeni na urazy klatki piersiowej i brzucha na skutek wtórnej kolizji. W niektórych przypadkach stoły miały słabą strukturę; w prosty sposób można je było odłączyć od ścian bocznych i/lub podłogi, do których były przymocowane. W następstwie stawały się one niekontrolowanymi pociskami, które uderzały pasażerów i powodowały ich obrażenia. W artykule przedstawiono analizę wyników wypadku dla typowego stołu. Wyniki dostarczają wiedzę o bezpieczeństwie w razie zaistnienia 98 E. Matsika, Q. Peng wypadku z udziałem stołu, podają informacje o skutkach. Materiały stosowane na stoły zostały zbadane za pomocą quasi-statycznych testów ściskających. Ponadto, przeprowadzono eksperymentalne dynamiczne testy wykorzystujące wahadło. Wyniki dostarczają informacji na temat potencjalnego oddziaływania stołu na pasażera w momencie zderzenia. Siły kontaktowe są porównywalne z progami tolerancji, odpowiadającym klatce piersiowej i jamie brzusznej, w wyniku czego można przewidzieć skutki kolizji. W związku z tym zaleca się wykonanie stołów z zachowaniem „równowagi funkcjonalności, wytrzymałości i bezpieczeństwa”.

3

HPLC determination of enantiomeric thiazolidine-2-carboxylic acid on chiral stationary phase with pre-column derivatization

Zhang Y., Peng Q., Zeng H., Yao S, Zhang Y., Song H.

Acta Chromatographica

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2013

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Vol. 25, no. 2

287--296

EN

A new high-performance liquid chromatography (HPLC) method has been developed and validated for determination of enantiomeric purity of thiazolidine-2-carboxylic acid within a short run time of less than 10 min. The method was based on pre-column derivatization of thiazolidine-2-carboxylic acid with aniline, and complete separation of enantiomers has been achieved on a Chiralcel OD-H analytical column (250 × 4.6 mm) using n-hexane-isopropanol (85:15 v/v) as mobile phase at a flow rate of 1.0 mL min-1 under UV and optical rotation (OR) detection. Detection wavelength was set at 254 nm. Then the effects of mobile phase and temperature on enantioselectivity were further evaluated. The method was validated with respect to precision, accuracy, linearity, limit of detection (LOD), limit of quantification (LOQ), and robustness. The recoveries were between 98.5 and 101.3% with percentage relative standard deviation less than 1.16%. The LOD and LOQ for the aniline derivatives of (+)-thiazolidine-2-carboxylic acid were 4.9 and 16.4 μg mL-1 and for the aniline derivatives (−)-thiazolidine-2-carboxylic acid were 5.1 and 17.2 μg mL-1, respectively.

4

Nearly Monodisperse Nanoparticles of Prussian Blue Analogue Ni3[Fe(CN)6]2×H2O

Li C. H., Wang J. T., Peng Q.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 2

345-348

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The effect of electromagnetic stirring on the microstructure and corrosion of mischmetal modified AZ91D magnesium alloy

Jin Y. X., Hua L., Xu X., Peng Q.

Materials Science Poland

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2009

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Vol. 27, No. 1

171--185

EN

The microstructure and corrosion behaviour of mischmetal modified AZ91D magnesium alloy in the presence or absence of a rotating electromagnetic field have been investigated. The study suggests that the size and volume fraction of the ? (Mg17Al12) phase in the alloy decreases as magnetic field intensity increases. The immersion test results show that the mass loss for the alloy solidified in the absence of a magnetic filed is always larger than that for the alloy solidified under magnetic field. The electrochemical corrosion experiments indicate that the corrosion potential of the alloys increases from -1.56 to -1.51 V, while the corrosion current density decreases from 6.31 to 1.58 mAocm-2, and the charge transfer resistance increases from 3.17 to 11.32 k?ocm2 as the excitation voltage increases from 0 to 120 V. The enhancement of the corrosion resistance is attributed to the grain refinement, and to the volume fraction reduction of the ? (Mg17Al12) phase under a rotating electromagnetic field.