Sample records for mg rdx kg-1

  1. Rapacuronium 2.0 or 2.5 mg kg(-1) for rapid-sequence induction : comparison with succinylcholine 1.0 mg kg(-1)

    Blobner, M; Mirakhur, RK; Wierda, JMKH; Wright, PMC; Olkkola, KT; Debaene, B; Pendeville, P; Engbaek, J; Rietbergen, H; Sparr, HJ


    The purpose of this nine-centre study in 602 patients was to show that the frequency of acceptable intubating conditions after rapacuronium 2.0 or 2.5 mg kg(-1) is not more than 10% lower than the frequency after succinylcholine 1.0 mg kg(-1) during rapid-sequence induction of anaesthesia with fenta

  2. Sugammadex 4.0 mg kg-1 reversal of deep rocuronium-induced neuromuscular blockade

    Yu, Buwei; Wang, Xiangrui; Hansen, Søren Helbo


    Objective: Maintenance of deep Neuro Muscular Blockade (NMB) until the end of surgery may be beneficial in some surgical procedures. The selective relaxant binding agent sugammadex rapidly reverses deep levels of rocuronium-induced NMB. The purpose of this study was to evaluate the efficacy...... and safety of sugammadex 4.0 mg kg-1 for reversal of deep rocuronium-induced NMB in Chinese and Caucasian patients. Methods: This was an open-label, multicenter, prospective Phase III efficacy study in adult American Society of Anesthesiologists Class 1-3 patients scheduled for surgery under general...... anesthesia and requiring deep NMB. All patients received intravenous propofol and opioids for induction and maintenance of anesthesia, and a single intubation dose of rocuronium 0.6 mg/kg, with maintenance doses of 0.1-0.2 mg/kg as required. Sugammadex 4.0 mg/kg was administered after the last dose...

  3. Efficacy, safety and pharmacokinetics of sugammadex 4 mg kg-1 for reversal of deep neuromuscular blockade in patients with severe renal impairment.

    Panhuizen, I F; Gold, S J A; Buerkle, C; Snoeck, M M J; Harper, N J N; Kaspers, M J G H; van den Heuvel, M W; Hollmann, M W


    This study evaluated efficacy and safety of sugammadex 4 mg kg(-1) for deep neuromuscular blockade (NMB) reversal in patients with severe renal impairment (creatinine clearance [CLCR] Sugammadex 4 mg kg(-1) was administered at 1-2 post-tetanic counts for reversal of rocuronium NMB. Primary efficacy variable was time from sugammadex to recovery to train-of-four (T4/T1) ratio 0.9. Equivalence between groups was demonstrated if two-sided 95% CI for difference in recovery times was within -1 to +1 min interval. Pharmacokinetics of rocuronium and overall safety were assessed. The intent-to-treat group comprised 67 patients (renal n=35; control n=32). Median (95% CI) time from sugammadex to recovery to T4/T1 ratio 0.9 was 3.1 (2.4-4.6) and 1.9 (1.6-2.8) min for renal patients vs controls. Estimated median (95% CI) difference between groups was 1.3 (0.6-2.4) min; thus equivalence bounds were not met. One control patient experienced acceleromyography-determined NMB recurrence, possibly as a result of premature sugammadex (4 mg kg(-1)) administration, with no clinical evidence of NMB recurrence observed. Rocuronium, encapsulated by Sugammadex, was detectable in plasma at day 7 in 6 patients. Bioanalytical data for sugammadex were collected but could not be used for pharmacokinetics. Sugammadex 4 mg kg(-1) provided rapid reversal of deep rocuronium-induced NMB in renal and control patients. However, considering the prolonged sugammadex-rocuronium complex exposure in patients with severe renal impairment, current safety experience is insufficient to support recommended use of sugammadex in this population. NCT00702715. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  4. Postoperative impairment of motor function at train-of-four ratio ≥0.9 cannot be improved by sugammadex (1 mg kg-1).

    Baumüller, E; Schaller, S J; Chiquito Lama, Y; Frick, C G; Bauhofer, T; Eikermann, M; Fink, H; Blobner, M


    A train-of-four ratio (TOFR) ≥0.9 measured by quantitative neuromuscular monitoring is accepted as an indication of sufficient neuromuscular recovery for extubation, even though many postsynaptic acetylcholine receptors may still be inhibited. We investigated whether antagonism with sugammadex after spontaneous recovery to TOFR≥0.9 further improves muscle function or subjective well-being. Following recovery to TOFR≥0.9 and emergence from anaesthesia, 300 patients randomly received either sugammadex 1.0 mg kg(-1) or placebo. Fine motor function (Purdue Pegboard Test) and maximal voluntary grip strength were measured before and after surgery (before and after test drug administration). At discharge from the postanaesthesia care unit, well-being was assessed with numerical analogue scales and the Quality-of-Recovery Score 40 (QoR-40). Patients' fine motor function [6 (sd 4) vs 15 (3) pegs (30 s)(-1), Psugammadex or placebo, motor function was significantly improved in both groups but did not reach the preoperative level. There was no difference between groups at any time. Global well-being was unaffected (QoR-40: placebo, 174 vs 185; sugammadex, 175 vs 186, P>0.05). Antagonizing rocuronium at TOF≥0.9 with sugammadex 1.0 mg kg(-) (1) did not improve patients' motor function or well-being when compared with placebo. Our data support the view that TOFR≥0.9 measured by electromyography signifies sufficient recovery of neuromuscular function. The trial is registered at (NCT01101139). © The Author 2014. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  5. Children and parental anxiolysis in paediatric ambulatory surgery: a randomized controlled study comparing 0.3 mg kg-1 midazolam to tablet computer based interactive distraction.

    Marechal, C; Berthiller, J; Tosetti, S; Cogniat, B; Desombres, H; Bouvet, L; Kassai, B; Chassard, D; de Queiroz Siqueira, M


    The operating theatre, anaesthesia induction and separation from parents create fear and anxiety in children. Anxiety leads to adverse behavioral changes appearing and sometimes persisting during the postoperative period. Our aim was to compare the effects of midazolam (0.3 mg kg(-)(1): MDZ) for premedication with age-appropriate tablet game apps (TAB) on children anxiety during and after ambulatory surgery. A randomized controlled trial was conducted from May 16th, 2013 to March 25th, 2014 at the Children Hospital of Lyon. The primary outcome of this study was the change in m-YPAS score at the time of anaesthetic mask induction. Anxiety was also assessed in the waiting surgical area, at the time of separation with parents and when back in the ambulatory surgery ward. One hundred and eighteen patients aged four-11 yr were recruited, 60 in the TAB Group and 58 in the MDZ Group. Main endpoint was missing for three patients from the MDZ Group. At the time of mask induction, there was no significant difference between MDZ and TAB Group for the m-YPAS score (40.5 (18.6) vs 41.8 (20.7), P = 0.99). There was no significant correlation between m-YPAS score and its evolution over the four period of time between subjects. We were not able to show whether TAB is superior to MDZ to blunt anxiety in children undergoing ambulatory surgery. TAB is a non-pharmacological tool which has the capacity in reducing perioperative stress without any sedative effect in this population. NCT 02192710. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email:

  6. Growth changes of eighteen herbaceous angiosperms induced by Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in soil.

    Hagan, Frank L; Koeser, Andrew K; Dawson, Jeffrey O


    Study objectives were to describe and quantify growth responses (tolerance as shoot and root biomass accumulation) to soil-applied Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) treatments of eighteen terrestrial, herbaceous, angiospermous species and also; to determine how much of RDX, RDX transformation products, total N and RDX-derived N accumulated in the foliage. RDX altered growth of eighteen plant species or cultivars at levels of 100, 500, and 1,000 mg kg(-1)dry soil in a 75-d greenhouse study. Sixteen species or cultivars exhibited growth inhibition while two were stimulated in growth by RDX. A maximum amount of foliar RDX in a subset of three plant species was 36.0 mg per plant in Coronilla varia. Foliar concentrations of transformation products of RDX were low relative to RDX in the subset of three species. The proportion of RDX-N with respect to total N was constant, suggesting that foliar RDX transformation did not explain differences in tolerance. There was a δ (15)N shift towards that of synthetic RDX in foliage of the three species at a level of 1,000 mg kg(-1) RDX, proportional in magnitude to uptake of N from RDX and tolerance ranking.Reddened leaf margins for treated Sida spinosa indicate the potential of this species as a biosensor for RDX.

  7. First-principles investigation of decomposition and adsorption properties of RDX on the surface of MgH2

    Rao, Guo-Ning; Yao, Miao; Peng, Jin-Hua


    Surface adsorption and decomposition mechanisms of cyclotrimethylenetrinitramine (RDX) molecules on the MgH2 (1 1 0) crystal face are investigated in this paper by employing the First-Principles. With the N-NO2 bond of RDX molecules as a reference, 12 adsorption sites are considered that are vertical (V1-V6) and parallel (P1-P6) to the MgH2 (1 1 0) surface. Results show that these 12 types of adsorption of RDX molecules on the MgH2 (1 1 0) crystal face are all chemical adsorption with high heat release, where the vertical Mg-top position (V1) is the most stable adsorption configuration. In all the 12 types of chemical adsorption, RDX molecules are decomposed, through 4 mechanisms including bis-nitro mono-N-O bond rupture, mono-nitro mono-N-O bond rupture, mono-nitro bis-N-O bond rupture and mono-N-O2 bond rupture, where the V-type adsorption is due to N-O bond rupture and the P-type adsorption is due to N-NO2 bond rupture, resulting in RDX decomposition. Secondly, in proximity to the Fermi level, the density of states of the RDX molecule highly coincides with that of the MgH2 (1 1 0) crystal face, which is prone to cause orbital hybridization and RDX decomposition. Also, the density of states in proximity to the Fermi level is mainly contributed by nitro O atoms and ring N atoms of RDX, as well as Mg atoms of the MgH2 (1 1 0) crystal face, and these 3 types of atoms are also active centers for chemical adsorption and decomposition reaction. Finally, an obvious phenomenon of charge transfer is present between Mg atoms in the first layer of the MgH2 (1 1 0) crystal face and O atoms in the nitro group of RDX. Also, the charge change in O and Mg atoms in the V configuration is greater than that in the P configuration, indicating that the V configuration has stronger interaction between RDX and the MgH2 (1 1 0) crystal face, and thus RDX in the V configuration is more prone to decomposition and the V configuration represents a better adsorption mode.

  8. Toxicity and bioconcentration evaluation of RDX and HMX using sheepshead minnows in water exposures.

    Lotufo, Guilherme R; Gibson, Alfreda B; Yoo, J Leslie


    Lethal effects of the explosives RDX and HMX were assessed using ten-day water exposures to juvenile sheepshead minnows (Cyprinodon variegatus). For RDX, maximum mortality occurred during the first two days of exposure with a 10-d median lethal concentration (LC50) of 9.9 mg L(-1). The RDX 10-d median lethal residue (LR50) was 9.6 mg kg(-1) (34.9 μmol kg(-1)) wet weight (ww), the first RDX critical body residue reported for fish. Previous investigations reported that RDX body residues in marine amphipods up to 96 μmol kg(-1) ww and in marine mussels up to 86 μmol kg(-1) ww failed to result in significant mortality. The highest HMX concentration tested, corresponding to its apparent solubility limit in seawater (2.0 mg L(-1)), and the associated mean body residue (3 mg kg(-1) or 14 μmol kg(-1) ww) resulted in no significant mortality for exposed minnows. The mean 10-d bioconcentration factors for RDX (0.6-0.9 L kg(-1)) and HMX (0.3-1.6 L kg(-1)) were typically lower than 1, reflecting the low bioaccumulative potential for these compounds. Published by Elsevier Inc.

  9. Mg(BH4)2和MgH2对RDX热分解特性的影响%Effect of Mg(BH4) 2 and MgH2 on Thermal Decomposition Performance of RDX

    姚淼; 陈利平; 堵平; 彭金华


    在黑索今(RDX)中加入具有高热值的金属氢化物(Mg(BH4)2和MgH2)有望提高RDX的爆炸性能,但同时给RDX的安全使用带来挑战.为了探索RDX与这2种金属氢化物的相容性与安定性,采用差示扫描量热法(DSC)研究Mg(BH4)2和MgH2对RDX热分解性能的影响,并由DSC得到的数据计算动力学参数,参照GJB770B——2005的方法分析这2种金属氢化物与RDX的相容性和安定性.结果表明,加入Mg(BH4)2使RDX的表观活化能从159.22 kJ/mol增加至180.27 kJ/mol,加入MgH2使RDX的表观活化能降低至133.69 kJ/mol; Mg(BH4)2与RDX的相容性为1级,MgH2与RDX的相容性为3级,加入Mg(BH4)2使RDX的安定性有所提高,加入MgH2降低了RDX的安定性.因此,在将MgH2作为RDX的高能添加剂以前,必须首先提高其与RDX的相容性以保证试验和存储过程的安全.%Metal hydrides ( Mg ( BH4) 2 and MgH2 ) with high heat values are expected to improve the explosion properties of RDX. However, they bring safety problems at the same time. In order to explore the consistencies between RDX and these two kinds of metal hydrides, the DSC was used to study the thermal decomposition characteristics of RDX influenced by the addition of Mg( BH4) 2 and MgH2. The consistencies between RDX and two kinds of metal hydrides were calculated and compared though the standard GJB770B - 2005 respectively. In addition, the stabilities of the mixtures were obtained, too. The results show that the addition of Mg(BH4)2 increases the apparent activation energy from 159. 22 kj/mol to 182.27 kj/mol and the addition of MgH2 decreases the apparent activation energy of RDX to 133. 69 kj/mol. The consistency grade of Mg( BH4 )2/RDX is 1 and the consistency grade of MgH2/RDX is 3 besides, the addition of Mg(BH4)2 is benefit to the stability of RDX and the addition of MgH2 lower the stability of RDX. So, how to enhance the consistency between RDX and MgH2 is the principal problem when adding MgH2 to RDX.

  10. Dynamic and equilibrium studies of the RDX removal from soil using CMC-coated zerovalent iron nanoparticles.

    Naja, Ghinwa; Apiratikul, Ronbanchob; Pavasant, Prasert; Volesky, Bohumil; Hawari, Jalal


    Rapid chemical degradation of toxic RDX explosive in soil can be accomplished using zerovalent nanoiron suspension stabilized in dilute carboxymethyl cellulose solution (CMC-ZVINs). The effect of operating conditions (redox-potential, Fe/RDX molar ratio) was studied on batchwise removal of RDX in contaminated soil. While anaerobic conditions resulted in 98% RDX removal in 3 h, only slightly over 60% RDX removal could be attained under aerobic conditions. The molar ratio did not have any influence on the intermediate and final RDX degradation products (methylenedinitramine, nitroso derivative, N(2), N(2)O, NO(2)(-)), however, their distribution changed. Dynamic studies were conducted using a flow-through short column packed with RDX-contaminated soil and fed with CMC-ZVINs. The column was operated at two interstitial velocities (2.2 and 1.6 cm min(-1)), resulting in the 76.6% and 95% removal of the initial RDX soil contamination load (60 mg kg(-1)), respectively. While the column operating conditions could be further optimized, 95% of the RDX initially present in the contaminated soil packed in the column was degraded when flushed with a CMC-ZVINs suspension in this work.

  11. Neurotoxicology of Cyclotrimethylenetrinitramine (RDX).


    experiments showed that RDX produced a multitude of behavioral effects. More specifically, when compared to vehicle-treated (2U carboxymethylcellulose in...Users of Laboratory Animals," prepared by the Committee on the Care and Use of Laboratory Animals of the Institute of Laboratory Animal Resources...behavioral effects. More specifically, when compared to vehicle-treated (2% carboxymethylcellulose in water) rats, RDX (12.5-50 mg/kg), p.o., 2-hr

  12. Concentration-dependent RDX uptake and remediation by crop plants.

    Chen, Diejun; Liu, Z Lewis; Banwart, Wanye


    The potential RDX contamination of food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species maize (Zea mays), sorghum (Sorghum sudanese), wheat (Triticum aestivum), and soybean (Glycine max) were capable of RDX uptake with more in aerial parts than roots. The accumulation of RDX in the plant tissue is concentration-dependent up to 21 mg RDX/L solution or 100 mg RDX/kg soil but not proportionally at higher RDX levels from 220 to 903 mg/kg soil. While wheat plant tissue harbored the highest RDX concentration of 2,800 μg per gram dry biomass, maize was able to remove a maximum of 3,267 μg RDX from soil per pot by five 4-week plants at 100 mg/kg of soil. Although RDX is toxic to plants, maize, sorghum, and wheat showed reasonable growth in the presence of the chemical, whereas soybeans were more sensitive to RDX. Results of this study facilitate assessment of the potential invasion of food chain by RDX-contaminated soils.

  13. Oral bioavailability of cyclotrimethylenetrinitramine (RDX) from contaminated site soils in rats.

    Crouse, Lee C B; Michie, Mark W; Major, Michael A; Leach, Glenn J; Reddy, Gunda


    Cyclotrimethylenetrinitramine (RDX), a commonly used military explosive, was detected as a contaminant of soil and water at Army facilities and ranges. This study was conducted to determine the relative oral bioavailability of RDX in contaminated soil and to develop a method to derive bioavailability adjustments for risk assessments using rodents. Adult male Sprague-Dawley rats preimplanted with femoral artery catheters were dosed orally with gelatin capsules containing either pure RDX or an equivalent amount of RDX in contaminated soils from Louisiana Army Ammunition Plant (LAAP) (2300 microg/g of soil) or Fort Meade (FM) (670 microg/g of soil). After dosing rats, blood samples were collected from catheters at 2-h intervals (2, 4, 6, 8, 10, and 12) and at 24 and 48 h. RDX levels in the blood were determined by gas chromatography. The results show that the peak absorption of RDX in blood was 6 h for neat RDX (1.24 mg/kg) and for RDX from contaminated soil (1.24 mg/kg) of LAAP. Rats dosed with RDX-contaminated FM soil (0.2 mg/kg) showed peak levels of RDX in blood at 6 h, whereas their counterparts that received an identical dose (0.2 mg/kg) of neat RDX showed peak absorption at 4 h. The blood levels of absorbed RDX from LAAP soil were about 25% less than for neat RDX, whereas the bioavailability of RDX from FM soils was about 15% less than that seen in rats treated with neat RDX (0.2 mg/kg). The oral bioavailability in rats fed RDX in LAAP soil and the FM soil was reduced with the neat compound but decrease in bioavailability varied with the soil type.

  14. Merits of RDX

    H. K. Acharya


    Full Text Available The explosive properties of RDX have been compared in details with those of other high explosives, such as, picric acid, TNT, CE and PETN, in respect of (i Rate of detonation, (ii Brisance,(iii Blasting power, (ivSensitivity, (v Stability and (vi Fragmentation. It has been pointed out that RDX is superior to all other modern high explosives hitherto used for blasting, shattering and fragmentation purposes.

  15. Effect of Nano-Magnesium Hydride on the Thermal Decomposition Behaviors of RDX

    Miao Yao


    Full Text Available In order to improve the detonation performance of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX explosive, addictives with high heat values were used, and magnesium hydride (MgH2 is one of the candidates. However, it is important to see whether MgH2 is a safe addictive. In this paper, the thermal and kinetic properties of RDX and mixture of RDX/MgH2 were investigated by differential scanning calorimeter (DSC and accelerating rate calorimeter (ARC, respectively. The apparent activation energy (E and frequency factor (A of thermal explosion were calculated based on the data of DSC experiments using the Kissinger and Ozawa approaches. The results show that the addition of MgH2 decreases both E and A of RDX, which means that the mixture of RDX/MgH2 has a lower thermal stability than RDX, and the calculation results obtained from the ARC experiments data support this too. Besides, the most probable mechanism functions about the decomposition of RDX and RDX/MgH2 were given in this paper which confirmed the change of the decomposition mechanism.

  16. Isolation and characterization of RDX-degrading Rhodococcus species from a contaminated aquifer.

    Bernstein, Anat; Adar, Eilon; Nejidat, Ali; Ronen, Zeev


    Groundwater contamination by the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a global problem. Israel's coastal aquifer was contaminated with RDX. This aquifer is mostly aerobic and we therefore sought aerobic bacteria that might be involved in natural attenuation of the compound in the aquifer. RDX-degrading bacteria were captured by passively sampling the indigenous bacteria onto sterile sediments placed within sampling boreholes. Aerobic RDX biodegradation potential was detected in the sediments sampled from different locations along the plume. RDX degradation with the native sampled consortium was accompanied by 4-nitro-2,4-diazabutanal formation. Two bacterial strains of the genus Rhodococcus were isolated from the sediments and identified as aerobic RDX degraders. The xplA gene encoding the cytochrome P450 enzyme was partially (~500 bp) sequenced from both isolates. The obtained DNA sequences had 99% identity with corresponding gene fragments of previously isolated RDX-degrading Rhodococcus strains. RDX degradation by both strains was prevented by 200 μM of the cytochrome P450 inhibitor metyrapone, suggesting that cytochrome P450 indeed mediates the initial step in RDX degradation. RDX biodegradation activity by the T7 isolate was inhibited in the presence of nitrate or ammonium concentrations above 1.6 and 5.5 mM, respectively (100 mg l(-1)) while the T9N isolate's activity was retarded only by ammonium concentrations above 5.5 mM. This study shows that bacteria from the genus Rhodococcus, potentially degrade RDX in the saturated zone as well, following the same aerobic degradation pathway defined for other Rhodococcus species. RDX-degrading activity by the Rhodococcus species isolate T9N may have important implications for the bioremediation of nitrate-rich RDX-contaminated aquifers.

  17. Microaerophilic degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by three Rhodococcus strains.

    Fuller, M E; Perreault, N; Hawari, J


    The goal of this study was to compare the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by three Rhodococcus strains under anaerobic, microaerophilic (RDX as the sole nitrogen source. RDX and RDX metabolite concentrations were measured over time. Under microaerophilic conditions, the bacteria degraded RDX, albeit about 60-fold slower than under fully aerobic conditions. Only the breakdown product, 4-nitro-2,4-diazabutanal (NDAB) accumulated to measurable concentrations under microaerophilic conditions. RDX degraded quickly under both aerated and static aerobic conditions (DO allowed to drop below 1 mg l(-1)) with the accumulation of both NDAB and methylenedinitramine (MEDINA). No RDX degradation was observed under strict anaerobic conditions. The Rhodococcus strains did not degrade RDX under strict anaerobic conditions, while slow degradation was observed under microaerophilic conditions. The RDX metabolite NDAB was detected under both microaerophilic and aerobic conditions, while MEDINA was detected only under aerobic conditions. IMPACT AND SIGNIFICANCE OF THE STUDY: This work confirmed the production of MEDINA under aerobic conditions, which has not been previously associated with aerobic RDX degradation by these organisms. More importantly, it demonstrated that aerobic rhodococci are able to degrade RDX under a broader range of oxygen concentrations than previously reported.

  18. Role of soil organic carbon and colloids in sorption and transport of TNT, RDX and HMX in training range soils.

    Sharma, Prasesh; Mayes, Melanie A; Tang, Guoping


    Contamination of soils and groundwater by munitions compounds (MCs) is of significant concern at many U.S. Department of Defense sites. Soils were collected from operational training ranges in Maryland (APG), Massachusetts (MMR-B and MMR-E) and Washington (JBLM) and sorption and transport studies were conducted to investigate the effects of soil organic carbon (OC) and textural clay content on fate of dissolved MCs (TNT, RDX, HMX). Sorption experiments showed higher distribution coefficients [TNT:42-68 L kg(-1), RDX:6.9-8.7 L kg(-1) and HMX:2.6-3.1 L kg(-1)] in OC rich soils (JBLM, MMR-E) compared to clay rich soils (MMR-B and APG) [TNT:19-21 L kg(-1), RDX:2.5-3.4 L kg(-1), HMX:0.9-1.2 L kg(-1)]. In column experiments, breakthrough of MCs was faster in MMR-B and APG compared to MMR-E and JBLM soils. Among TNT, RDX and HMX, breakthrough was fastest for RDX followed by HMX and TNT for all columns. Defining the colloidal fraction as the difference between unfiltered samples and samples filtered with a 3 kDa filter, ~36%, ~15% and ~9% of TNT, RDX and HMX were found in the colloidal fraction in the solutions from sorption experiments, and around 20% of TNT in the effluent from the transport experiments. Results demonstrate that OC rich soils may enhance sorption and delay transport of TNT, RDX and HMX compared to clay-rich soils. Further, transport of TNT may be associated with soil colloid mobilization.

  19. Effect of Nano-Magnesium Hydride on the Thermal Decomposition Behaviors of RDX

    Miao Yao; Liping Chen; Guoning Rao; Jianxin Zou; Xiaoqin Zeng; Jinhua Peng


    In order to improve the detonation performance of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) explosive, addictives with high heat values were used, and magnesium hydride (MgH2) is one of the candidates. However, it is important to see whether MgH2 is a safe addictive. In this paper, the thermal and kinetic properties of RDX and mixture of RDX/MgH2 were investigated by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. The apparent activation ener...

  20. Absorption, Distribution, Metabolism, and Excretion of 14C-RDX Following Oral Administration to Minipigs


    RDX. On the day of dosing, 30.086 mg of 14C-RDX and 4,218.6 mg of RDX were combined with 450 mL of 0.5% carboxymethylcellulose in water. The dose...switching valve. Negative Ion LC/MS/MS Analyses Selective multiple reaction monitoring (MRM) was used as survey scan to activate product ion scans...MS2) through preset information dependent acquisition (IDA) criteria. Q1 full scan, precursor scan (prec) of specific product ions at m/z 61 and 46

  1. Detonation Heat of Boron-contained Explosive Based on RDX%黑索今基含硼炸药的爆热性能

    黄亚峰; 王晓峰; 冯晓军


    为了研究黑索今(RDX)基含硼(B)炸药的能量特性,采用GJB772A - 1997方法701.1对7种含硼粉的RD×炸药:RDX/B/EVA(乙烯-醋酸乙烯共聚物)-90/8/2、RDX/B/EVA-88/10/2、RDX/B/EVA-86/12/2、RDX/B/EVA-83/15/2、RDX/B/EVA-78/20/2、RDX/B/EVA-75/23/2、RDX/B/EVA-68/30/2的爆热进行了测试并进行了理论计算.结果表明,硼粉含量为8%~20%时,混合炸药的爆热与硼粉含量之间存在线性关系,硼粉能够提高混合炸药的爆热.测量和计算的最大爆热值分别是7162 kJ·kg-1和8967 kJ·kg-1,分别对应为B/O比为0.87的组分为RDX/B/EVA-78/20/2的含硼炸药和B/O比为0.61的组分为RDX/B/EVA-83/15/2的含硼炸药.当爆热值达到最大后,随硼粉含量的增加,爆热值减小.%In order to investigate the energy characteristics of RDX based boron-contained explosive,the heats of detonation ( Qdet) of seven explosives; RDX/B/EVA-90/8/2.RDX/B/EVA-88/10/2 .RDX/B/EVA-86/12/2 , RDX/B/EVA-83/15/2, RDX/B/EVA-78/20/2 , RDX/B/EVA-75/23/2 .RDX/B/EVA-68/30/2 mixtures were measured by standard method of GJB772A -97 -701.1 ,and theoretical calculation of Qdet was performed. The results show that there is a linear relationship between the heats of detonation of explosive mixtures and the boron content in the range of 8% to 20% .indicating that boron powder makes the value of Qdet of RDX increase. The measured and calculated maximum heats of detonation are 7162 kj · Kg-1 for RDX/B/EVA-78/20/2 mixture with B/O ratio of 0.87 and 8967 kj · Kg-1 for RDX/B/EVA-83/15/2 mixture with B/O ratio of 0.61 respectively. After maximum values of Qdet, with increasing the boron content,the value of Qdel decreases.

  2. Laboratory evaluation of bioaugmentation for aerobic treatment of RDX in groundwater.

    Fuller, Mark E; Hatzinger, Paul B; Condee, Charles W; Andaya, Christina; Vainberg, Simon; Michalsen, Mandy M; Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Eaton, Hillary; Istok, Jonathan D


    The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km+. All three strains were transported through the columns and eluted ahead of the conservative bromide tracer, although the total breakthrough varied by strain. The introduced cells responded to biostimulation with fructose (18 mg L(-1), 0.1 mM) by degrading dissolved RDX (0.5 mg L(-1), 2.3 µM). The strains retained RDX-degrading activity for at least 6 months following periods of starvation when no fructose was supplied to the column. Post-experiment analysis of the soil indicated that the residual cells were distributed along the length of the column. When the strains were grown to densities relevant for field-scale application, the cells remained viable and able to degrade RDX for at least 3 months when stored at 4 °C. These results indicate that bioaugmentation may be a viable option for treating RDX in large dilute aerobic plumes.

  3. RDX/Sylgard extrudable explosive development

    Osborn, A.G.; Schmitz, G.T.; Stallings, T.L.; West, G.T.; Ashcraft, R.W.


    Formulation procedures for X-0208, an 80 percent RDX/20 percent Sylgard extrudable, have been developed. The extrudable explosive, made from a mixture of micronized RDX and Class E RDX, will sustain detonation in a 1.65 mm channel and can be mechanically extruded into ribbon-type configurations.

  4. RDX degradation in bioaugmented model aquifer columns under aerobic and low oxygen conditions.

    Fuller, Mark E; Hatzinger, Paul B; Condee, Charles W; Andaya, Christina; Rezes, Rachel; Michalsen, Mandy M; Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Alon Blakeney, G; Istok, Jonathan D; Hammett, Steven A


    Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation. Replicate columns were then bioaugmented with either Gordonia sp. KTR9, Pseudomonas fluorescens I-C (Ps I-C), or both strains. Under aerobic conditions (influent dissolved oxygen (DO) >6 mg/L), RDX was degraded following the addition of fructose, and to a lesser extent with lactate, in columns bioaugmented with KTR9. No degradation was observed in columns bioaugmented with only Ps I-C under aerobic conditions, consistent with the known anaerobic RDX degradation pathway for this strain. When influent DO was reduced to RDX degradation was observed in the KTR9-bioaugmented column, and some degradation was also observed in the Ps I-C-bioaugmented column. After DO levels were kept below 1 mg/L for more than a month, columns bioaugmented with KTR9 became unresponsive to fructose addition, while RDX degradation was still observed in the Ps I-C-bioaugmented columns. These results indicate that bioaugmentation with the aerobic RDX degrader KTR9 could be effective at sites where site geology or geochemistry allow higher DO levels to be maintained. Further, inclusion of strains capable of anoxic RDX degradation such as Ps I-C may facilitate bimodal RDX removal when DO levels decrease.

  5. Investigations of transcript expression in fathead minnow (Pimephales promelas) brain tissue reveal toxicological impacts of RDX exposure.

    Gust, Kurt A; Wilbanks, Mitchell S; Guan, Xin; Pirooznia, Mehdi; Habib, Tanwir; Yoo, Leslie; Wintz, Henri; Vulpe, Chris D; Perkins, Edward J


    Production, usage and disposal of the munitions constituent (MC) cyclotrimethylenetrinitramine (RDX) has led to environmental releases on military facilities. The chemical attributes of RDX are conducive for leaching to surface water which may put aquatic organisms at risk of exposure. Because RDX has been observed to cause aberrant neuromuscular effects across a wide range of animal phyla, we assessed the effects of RDX on central nervous system (CNS) functions in the representative aquatic ecotoxicological model species, fathead minnow (Pimephales promelas). We developed a fathead minnow brain-tissue cDNA library enriched for transcripts differentially expressed in response to RDX and trinitrotoluene (TNT) exposure. All 4,128 cDNAs were sequenced, quality filtered and assembled yielding 2230 unique sequences and 945 significant blastx matches (E ≤10(-5)). The cDNA library was leveraged to create custom-spotted microarrays for use in transcript expression assays. The impact of RDX on transcript expression in brain tissue was examined in fathead minnows exposed to RDX at 0.625, 2.5, 5, 10mg/L or an acetone-spike control for 10 days. Overt toxicity of RDX in fathead minnow occurred only at the highest exposure concentration resulting in 50% mortality and weight loss. Conversely, Bayesian analysis of microarray data indicated significant changes in transcript expression at concentrations as low as 0.625 mg/L. In total, 154 cDNAs representing 44 unique transcripts were differentially expressed in RDX exposures, the majority of which were validated by reverse transcriptase-quantitative PCR (RT-qPCR). Investigation of molecular pathways, gene ontology (GO) and individual gene functions affected by RDX exposures indicated changes in metabolic processes involved in: oxygen transport, neurological function, calcium binding/signaling, energy metabolism, cell growth/division, oxidative stress and ubiquitination. In total, our study indicated that RDX exposure affected

  6. Single doses of ivermectin 400 micrograms/kg-1: the most effective dosage in bancroftian filariasis.

    Moulia-Pelat, J P; Glaziou, P; Nguyen, L N; Cartel, J L


    Forty-three Wuchereria bancrofti carriers were given four successive semi-annual single doses of ivermectin 100 (IVER 100). The geometric mean microfilaremia (mf) recurrence percentage as compared to the pre-initial treatment mf level was 35%, 21%, 17% and 17% at 6, 12, 18 and 24 months, respectively. However, the recurrence of mf 6 months after the fourth treatment remained high in several individuals: 15 have been considered as 'bad responders' and 28 as 'good responders' individuals. At month 24 (M 24), they were randomly allocated into 2 groups. A first group was treated with a fifty and a sixth dose of IVER 100, at M24 and M30, respectively; the second one was treated, at the same time, with single doses of IVER 400 (IVER 400). At M 36, the mf recurrence percentage (mf M36/mf M0) was significantly higher in patients treated with IVER 100 than IVER 400 (11% vs 1%, p < 10(-4). From the group IVER 100, 6 out of the 8 'bad responders' remained 'bad responders' whereas there were none of the 7 in the group IVER 400. Moreover, there were only 2 more patients in the group IVER 100 showing sustained complete zero mf, whereas they were 13 in the group IVER 400. Single doses of IVER 400 were effective on 'bad responders'; IVER 400 must be recommended for semi-annual mass treatment in bancroftian filariasis.

  7. Effects of the combination of decitabine and homoharringtonine in SKM-1 and Kg-1a cells.

    Geng, Suxia; Yao, Han; Weng, Jianyu; Tong, Jiaqi; Huang, Xin; Wu, Ping; Deng, Chengxin; Li, Minming; Lu, Zesheng; Du, Xin


    The methylation inhibitor decitabine (DAC) has great therapeutic value for myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, DAC monotherapy is associated with relatively low rates of overall response and complete remission. Previous studies have shown promising results for combination treatment regimens including DAC. Homoharringtonine (HHT), an alkaloid from Chinese natural plants and Cephalotaxus, has demonstrated potential for leukemia treatment. Our studies have suggested that the combination of DAC and HHT has synergistic effects for inhibiting the viability of SKM-1 and Kg-1a cells. This combination leads to enhanced inhibition of colony formation and apoptosis induction compared with DAC alone in SKM-1 but not Kg-1a cells. Only high-dose DAC and HHT significantly up-regulate caspase-3 and caspase-9 and inhibit BCL-XL in the SKM-1 cell line. The combined effects of DAC plus HHT on apoptosis may not only depend on regulation of the apoptosis-related genes we examined but others as well. HHT had no demethylation effects, and HHT in combination with DAC had no enhanced effects on hypomethylation and DNMT1, DNMT3A and DNMT3B mRNA expression in SKM-1 cells. Overall, these results suggest that DAC used in combination with HHT may have clinical potential for MDS treatment.

  8. A systems toxicology approach to elucidate the mechanisms involved in RDX species-specific sensitivity.

    Warner, Christopher M; Gust, Kurt A; Stanley, Jacob K; Habib, Tanwir; Wilbanks, Mitchell S; Garcia-Reyero, Natàlia; Perkins, Edward J


    Interspecies uncertainty factors in ecological risk assessment provide conservative estimates of risk where limited or no toxicity data is available. We quantitatively examined the validity of interspecies uncertainty factors by comparing the responses of zebrafish (Danio rerio) and fathead minnow (Pimephales promelas) to the energetic compound 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), a known neurotoxicant. Relative toxicity was measured through transcriptional, morphological, and behavioral end points in zebrafish and fathead minnow fry exposed for 96 h to RDX concentrations ranging from 0.9 to 27.7 mg/L. Spinal deformities and lethality occurred at 1.8 and 3.5 mg/L RDX respectively for fathead minnow and at 13.8 and 27.7 mg/L for zebrafish, indicating that zebrafish have an 8-fold greater tolerance for RDX than fathead minnow fry. The number and magnitude of differentially expressed transcripts increased with increasing RDX concentration for both species. Differentially expressed genes were enriched in functions related to neurological disease, oxidative-stress, acute-phase response, vitamin/mineral metabolism and skeletal/muscular disorders. Decreased expression of collagen-coding transcripts were associated with spinal deformity and likely involved in sensitivity to RDX. Our work provides a mechanistic explanation for species-specific sensitivity to RDX where zebrafish responded at lower concentrations with greater numbers of functions related to RDX tolerance than fathead minnow. While the 10-fold interspecies uncertainty factor does provide a reasonable cross-species estimate of toxicity in the present study, the observation that the responses between ZF and FHM are markedly different does initiate a call for concern regarding establishment of broad ecotoxicological conclusions based on model species such as zebrafish.

  9. Degradation of TATP, TNT, and RDX using mechanically alloyed metals

    Clausen, Christian (Inventor); Geiger, Cherie (Inventor); Sigman, Michael (Inventor); Fidler, Rebecca (Inventor)


    Bimetallic alloys prepared in a ball milling process, such as iron nickel (FeNi), iron palladium (FePd), and magnesium palladium (MgPd) provide in situ catalyst system for remediating and degrading nitro explosive compounds. Specifically, munitions, such as, 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), nitrocellulose and nitroglycerine that have become contaminants in groundwater, soil, and other structures are treated on site to remediate explosive contamination.

  10. Transcriptomic analysis of RDX and TNT interactive sublethal effects in the earthworm Eisenia fetida

    Gong, Ping; Guan, Xin; Inouye, Laura S; Deng, Youping; Pirooznia, Mehdi; Perkins, Edward J


    Background Explosive compounds such as TNT and RDX are recalcitrant contaminants often found co-existing in the environment. In order to understand the joint effects of TNT and RDX on earthworms, an important ecological and bioindicator species at the molecular level, we sampled worms (Eisenia fetida) exposed singly or jointly to TNT (50 mg/kg soil) and RDX (30 mg/kg soil) for 28 days and profiled gene expression in an interwoven loop designed microarray experiment using a 4k-cDNA array. Lethality, growth and reproductive endpoints were measured. Results Sublethal doses of TNT and RDX had no significant effects on the survival and growth of earthworms, but significantly reduced cocoon and juvenile counts. The mixture exhibited more pronounced reproductive toxicity than each single compound, suggesting an additive interaction between the two compounds. In comparison with the controls, we identified 321 differentially expressed transcripts in TNT treated worms, 32 in RDX treated worms, and only 6 in mixture treated worms. Of the 329 unique differentially expressed transcripts, 294 were affected only by TNT, 24 were common to both TNT and RDX treatments, and 3 were common to all treatments. The reduced effects on gene expression in the mixture exposure suggest that RDX might interact in an antagonistic manner with TNT at the gene expression level. The disagreement between gene expression and reproduction results may be attributed to sampling time, absence of known reproduction-related genes, and lack of functional information for many differentially expressed transcripts. A gene potentially related to reproduction (echinonectin) was significantly depressed in TNT or RDX exposed worms and may be linked to reduced fecundity. Conclusions Sublethal doses of TNT and RDX affected many biological pathways from innate immune response to oogenesis, leading to reduced reproduction without affecting survival and growth. A complex interaction between mixtures of RDX and TNT was

  11. 白藜芦醇增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用%Resveratrol enhances cytotoxicity of TRAIL to human promyloblastic leukemia KG-1a cells

    胡亮杉; 孙茂本; 曾雅丽; 李玉华; 邓兰; 郭坤元


    目的:观察白藜芦醇作用前后TRAIL对人髓系白血病KG-1a细胞的细胞毒作用的变化.方法:流式细胞仪检测KG-1a细胞表面CD34 和CD38的表达,二甲氧唑黄(XTT)细胞增殖及细胞毒性检测试剂盒检测白藜芦醇作用前后TRAIL对KG-1a细胞增殖的影响,AnnexinV-FITC/PI染色流式细胞仪检测细胞凋亡变化.流式细胞仪检测白藜芦醇作用前后KG-1a细胞表面TRAIL死亡受体表达变化.结果:人髓系白血病KG-1a细胞 CD34+CD38-占(58.67±2.87)%,10~1 000 ng/ml 的TRAIL对KG-1a细胞增殖无明显影响,但对白藜芦醇作用后的KG-1a细胞的增殖有明显抑制作用,白藜芦醇能促进TRAIL诱导KG-1a细胞凋亡,并能上调KG-1a细胞表面TRAIL死亡受体DR5的表达.结论:白藜芦醇能增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用,其机制可能与白藜芦醇上调KG-1a细胞表面TRAIL死亡受体DR5的表达有关.%Objective :To explore the cytotoxicity of TRAIL to human acute promyeloblastic leukemia KG-1a cells treated with resvera trol .Methods :The expression of CD34 and CD38 on the Surface of KG-1 cells was detected by flow cytometry ;The effects of various concentration TRAIL on proliferation of KG-1a cells treated with or without resveratrol were analyzed by XTT cell proliferation and cytotoxicity assay kit ;The changes of apoptosis in KG-1a cells treated with or without resveratrol induced by TRAIL were detected by flow cytometry through the staining of AnnexinV-FITC /PI ;The effects of resveratrol on the expression of DR4/5 on the surface of KG-1a cells were detected by flow cytometry .Results :The CD34+ CD38- percent age of KG-1a cells was (58 .67±2 .87 )% ;10-1 000 ng/ml of TRAIL had no effects on the proliferation of KG-1a cells ,while could inhibit the proliferation of KG-1a cells treated with resveratrol ;Moreover ,resveratrol could enhance the apoptosis of KG-1a cells induced by TRAIL and up-regulate the expression of TIRAIL death receptors DR5

  12. Mechanism of RDX-Induced Seizures in Rats


    37.5 mg/ml in 1% methylcellulose, 0.1% Tween 80 in distilled water (vehicle). Control animals were dosed with the vehicle exclusively. Dosing...methylcelluose/0.2% Tween 80 ; this dose induced seizure in all animals with an average time to seizure onset of 11 min. For the present mechanistic study...animals were pair-dosed by oral gavage with either vehicle (1% methylcelluose/0.2% Tween 80 , 2 ml/kg, n=8) or RDX at 75 mg/kg (37.5 mg/ml, 2 ml/kg) in 1

  13. Terahertz interferometric imaging of RDX

    Sinyukov, Alexander M.; Barat, Robert B.; Gary, Dale E.; Michalopoulou, Zoi-Heleni; Zorych, Ivan; Zimdars, David; Federici, John F.


    Experimental results of homodyne terahertz interferometric 2-D imaging of RDX are presented. Continuous waves at 0.25-0.6 THz are used to obtain images of a C-4 sample at several THz frequencies. The performance of an N element detector array is imitated by only one detector placed at N positions. The distance between the C-4 sample and the detector array is ~30 cm. By taking interferometric images at several THz frequencies RDX can be recognized by the spectral peak at 0.82 THz. Simulations of interferometric images of two point sources of spherical waves are presented. The terahertz interferometric imaging method can be used in defense and security applications to detect concealed weapons, explosives as well as chemical and biological agents.

  14. Genomic investigation of year-long and multigenerational exposures of fathead minnow to the munitions compound RDX.

    Gust, Kurt A; Brasfield, Sandra M; Stanley, Jacob K; Wilbanks, Mitchell S; Chappell, Pornsawan; Perkins, Edward J; Lotufo, Guilherme R; Lance, Richard F


    We assessed the impacts of exposure to an environmentally representative concentration (0.83 mg/L) of the explosive cyclotrimethylenetrinitramine (RDX) on fathead minnows (Pimephales promelas) in one-year and multigenerational bioassays. In the one-year bioassay, impacts were assessed by statistical comparisons of females from breeding groups reared in control or RDX-exposure conditions. The RDX had no significant effect on gonadosomatic index or condition factor assayed at 1 d and at one, three, six, nine, and 12 months. The liver-somatic index was significantly increased versus controls only at the 12-month timepoint. RDX had no significant effect on live-prey capture rates, egg production, or fertilization. RDX caused minimal differential-transcript expression with no consistent discernable effect on gene-functional categories for either brain or liver tissues in the one-year exposure. In the multigenerational assay, the effects of acute (96 h) exposure to RDX were compared in fish reared to the F(2) generation in either control or RDX-exposure conditions. Enrichment of gene functions including neuroexcitatory glutamate metabolism, sensory signaling, and neurological development were observed comparing control-reared and RDX-reared fish. Our results indicated that exposure to RDX at a concentration representing the highest levels observed in the environment (0.83 mg/L) had limited impacts on genomic, individual, and population-level endpoints in fathead minnows in a one-year exposure. However, multigenerational exposures altered transcript expression related to neural development and function. Environ. Copyright © 2011 SETAC.

  15. Concentration-dependent RDX uptake and remediation

    The potential hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contamination of the food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species inc...

  16. Treatment of Wastewater Containing RDX by Fenton's Reagent

    XU Hang; ZHANG Dong-xiang; XU Wen-guo


    Fenton's reagent was employed to treat the wastewater containing RDX. The effects of FeSO4 concentration, H2O2 concentration, pH value, reaction time, temperature and initial COD of wastewater on residual COD of wastewater were investigated. The results show that the optimum FeSO4 concentration and pH are 700mg/L and 2.5, respectively, and the residual COD of wastewater decreases with the rise in H2O2 concentration, but increases with the rise in temperature. After Fenton's reagent treatment, the initial COD of less than 874 mg/L wastewater can meet effluent standard. Under conditions of 100 mg/L H2O2, 437 mg/L initial COD and 15 ℃ temperature, the lowest residual COD is obtained at 83.80 mg/L in 5 min.

  17. Treatment of HMX and RDX contamination

    Card, R.E. Jr.; Autenrieth, R. [Texas A& M Univ., College Station, TX (United States)


    HMX and RDX are often found in the soil, groundwater, and surface waters at facilities where they are manufactured as the result of negligent disposal methods. The toxicity of these compounds and their degradation products has led to concern about their fate in the environment and the potential for human exposure. HMX and RDX are recalcitrant in the environment with low rates of biodegradation and photolysis. Several methods of treating contaminated soils and waters have been developed and studied. Many of these technologies (i.e., carbon adsorption, oxidation, and chemical treatment) have been developed to treat munition plant wastewaters that are contaminated with explosives. These methods need to be adapted to remediate contaminated water. Other technologies such as bioremediation and composting are being developed as methods of remediating HMX and RDX contamination in a solid matrix. This report describes and evaluates each of these technologies. This report also describes the processes which affect HMX and RDX in the environment. The major transformation processes of RDX and HMX in the environment are biodegradation and photolysis. A major factor affecting the transport and treatment of RDX and HMX in soil-water environments is their sorption and desorption to soil particles. Finally, this report draws conclusions as to which treatment methods are currently most suitable for the remediation of contaminated soils and waters.

  18. TGF-β1对白血病KG-1细胞株Gli1表达的影响%Effect of TGF-β1 on Gli1 expression in KG-1 cell line

    李哲; 潘静


    Objective To prove that there was cross talk between Hh signaling pathway and TGF-β signaling pathway in KG-1 cells line. Methods (1) KG-1 cells were treated with 0. 1 ng/mL,l ng/mL,and 10 ng/mL TGF-β1 for 6 h,12 h,and 24 h respectively. Cells were collected after stimulation. Total mRNA was extracted. Glil expression was detected by real-time PCR. (2) KG-1 cells were treated with 5 ng/mL TGFβ1 and 5 ng/mL TGF-β1 +5 μmol SIS3 respectively for 24h. Cells were collected after stimulation. Total mRNA was extracted. Glil expression was detected. Results (1) When 1- 10 ng/mL TGF-β1 acted on the KG-1 cells respectively for 6 h, 12 h and 24 h, significant reduction of Glil mRNA in response to TGF-β1 was observed in KG-1 cells, emerging at 12 h and lasting at least 24 h,lower than that of the control group. (2) When 5 ng/mL TGF-β1 and 5 ng/mL TGF-β1 +5 μmol SIS3 acted on the KG-1 cells respectively for 24 h respectively,Glil expression of mRNA of control group was higher than that of TGF-β1 group, while much lower than that of TGF-β1 +SIS3 group. Conclusion TGF-β1significantly decreased Glil expression in KG-1 cells. Glil induction in KG-1 cells by TGF-β1 was a Smad3-dependent manner. This effect was independent from the Ptch/Smo axis.%目的 证明在白血病KG-1细胞株中存在TGF-β信号通路对Gli的调控作用.方法 (1)用0.1、1、10 ng/mL TGF-β1分别作用于KG-1细胞,时间分别为6、12、24 h.处理结束后收集细胞,提取mRNA,检测Gli1的表达.(2)5 ng/mL TGF-β1、5 ng/mL TGF-β1联合5 μmol SIS3分别作用于KG-1细胞24 h.处理结束后收集细胞,提取mRNA,检测Gli1的表达.结果 (1)1~10 ng/mL TGF-β1分别作用于KG-1细胞6、12、24 h,从12 h起并至少持续至24 h,其Gli1的mRNA表达较对照组明显减少;(2)5 ng/mL TGF-β1、5ng/mL TGF-β1联合5 μmol SIS3分别作用于KG-1细胞24 h,其Gli1的mRNA表达与对照组比较:5 ng/mL TGF-β1组较对照组降低,而5 ng/mL TGF-β1联合5 μmol SIS3组较

  19. Elevated root retention of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in coniferous trees.

    Schoenmuth, Bernd; Mueller, Jakob O; Scharnhorst, Tanja; Schenke, Detlef; Büttner, Carmen; Pestemer, Wilfried


    For decades, the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) has been used for military and industrial applications. Residues of RDX pollute soils in large areas globally and the persistence and high soil mobility of these residues can lead to leaching into groundwater. Dendroremediation, i.e. the long-term use of trees to clean up polluted soils, is gaining acceptance as a green and sustainable strategy. Although the coniferous tree species Norway spruce and Scots pine cover large areas of military land in Central Europe, the potential of any coniferous tree for dendroremediation of RDX is still unknown. In this study, uptake experiments with a (14)C-labelled RDX solution (30 mg L(-1)) revealed that RDX was predominantly retained in the roots of 6-year-old coniferous trees. Only 23 % (pine) to 34 % (spruce) of RDX equivalents (RDXeq) taken up by the roots were translocated to aboveground tree compartments. This finding contrasts with the high aerial accumulation of RDXeq (up to 95 %) in the mass balances of all other plant species. Belowground retention of RDXeq is relatively stable in fine root fractions, since water leaching from tissue homogenates was less than 5 %. However, remobilisation from milled coarse roots and tree stubs reached up to 53 %. Leaching from homogenised aerial tree material was found to reach 64 % for needles, 58 % for stems and twigs and 40 % for spring sprouts. Leaching of RDX by precipitation increases the risk for undesired re-entry into the soil. However, it also opens the opportunity for microbial mineralisation in the litter layer or in the rhizosphere of coniferous forests and offers a chance for repeated uptake of RDX by the tree roots.

  20. Neurotoxicogenomic investigations to assess mechanisms of action of the munitions constituents RDX and 2,6-DNT in Northern bobwhite (Colinus virginianus).

    Gust, Kurt A; Pirooznia, Mehdi; Quinn, Michael J; Johnson, Mark S; Escalon, Lynn; Indest, Karl J; Guan, Xin; Clarke, Joan; Deng, Youping; Gong, Ping; Perkins, Edward J


    Munitions constituents (MCs) including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), and TNT derivatives are recognized to elicit aberrant neuromuscular responses in many species. The onset of seizures resulting in death was observed in the avian model Northern bobwhite after oral dosing with RDX beginning at 8 mg/kg/day in subacute (14 days) exposures, whereas affective doses of the TNT derivative, 2,6-dinitrotoluene (2,6-DNT), caused gastrointestinal impacts, lethargy, and emaciation in subacute and subchronic (60 days) exposures. To assess and contrast the potential neurotoxicogenomic effects of these MCs, a Northern bobwhite microarray was developed consisting of 4119 complementary DNA (cDNA) features enriched for differentially-expressed brain transcripts from exposures to RDX and 2,6-DNT. RDX affected hundreds of genes in brain tissue, whereas 2,6-DNT affected few (RDX. Birds exhibiting RDX-induced seizures accumulated over 20x more RDX in brain tissues in comparison to non-seizing birds even within a common dose. In parallel, expression patterns were unrelated among seizing and non-seizing birds exposed to equivalent RDX doses. In birds experiencing seizures, genes related to neuronal electrophysiology and signal transduction were significantly affected. Comparative toxicology revealed strong similarity in acute exposure effects between RDX and the organochlorine insecticide dichlorodiphenyltrichloroethane (DDT) regarding both molecular mechanisms and putative mode of action. In a manner similar to DDT, we hypothesize that RDX elicits seizures by inhibition of neuronal cell repolarization postaction potential leading to heightened neuronal excitability and seizures facilitated by multiple molecular mechanisms.

  1. Global gene expression in rat brain and liver after oral exposure to the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Bannon, Desmond I; Dillman, James F; Hable, Michael A; Phillips, Christopher S; Perkins, Edward J


    RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) is a synthetic, high-impact, relatively stable explosive that has been in use since WWII. Exposure to RDX can occur in occupational settings (e.g., during manufacture) or through the inadvertent ingestion of contaminated environmental media such as groundwater. The toxicology of RDX is dominated by acute clonic-tonic seizures at high doses, which remit when exposure is removed and internal RDX levels decrease. Subchronic studies have revealed few other measurable toxic effects. The objective of this study was to examine the acute effects of RDX on the mammalian brain and liver using global gene expression analysis based on a predetermined maximum internal dose. Male Sprague-Dawley rats were given a single, oral, nonseizure-inducing dose of either 3 or 18 mg/kg RDX in a gel capsule. Effects on gene expression in the cerebral cortex and liver were assessed using Affymetrix Rat Genome 230 2.0 whole genome arrays at 0, 3.5, 24, and 48 h postexposure. RDX blood and brain tissue concentrations rapidly increased between 0 and 3.5 h, followed by decreases at 24 h to below the detection limit at 48 h. Pairwise comparison of high and low doses at each time point showed dramatic differential changes in gene expression at 3.5 h, the time of peak RDX in brain and blood. Using Gene Ontology, biological processes that affected neurotransmission were shown to be primarily down-regulated in the brain, the target organ of toxicity, while those that affected metabolism were up-regulated in the liver, the site of metabolism. Overall, these results demonstrate that a single oral dose of RDX is quickly absorbed and transported into the brain where processes related to neurotransmission are negatively affected, consistent with a potential excitotoxic response, whereas in the liver there was a positive effect on biological processes potentially associated with RDX metabolism.

  2. Sorption kinetics of TNT and RDX in anaerobic freshwater and marine sediments: Batch studies.

    Ariyarathna, Thivanka; Vlahos, Penny; Tobias, Craig; Smith, Richard


    Examination of the partitioning of explosives onto sediment in marine environments is critical to predict the toxicological impacts of worldwide explosive-contaminated sites adjacent to estuaries, wetlands, and the coastal ocean. Marine sediments have been identified as sites of enhanced munitions removal, yet most studies addressing these interactions focus on soils and freshwater sediments. The present study measured the kinetics of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) sorption onto 2 marine sediments of varying grain sizes (silt vs sand) and organic carbon (OC) content. Abiotic sediment sorption tests were performed at 23 °C, 15 °C, and 4 °C by spiking TNT and RDX solutions directly into anaerobic sediment slurries. Marine sediments showed significantly higher compound uptake rates (0.30-0.80 h(-1) ) than freshwater silt (0.0046-0.0065 h(-1) ) for both compounds, probably because of lower compound solubilities and a higher pH in marine systems. Equilibrium partition constants are on the same order of magnitude for marine silt (1.1-2.0 L kg(-1) sediment) and freshwater silt (1.4-3.1 L kg(-1) sediment) but lower for marine sand (0.72-0.92 L kg(-1) sediment). Total organic carbon content in marine sediments varied linearly with equilibrium partition constants for TNT and was moderately linear for RDX. Uptake rates and equilibrium constants of explosives are inversely correlated to temperature regardless of sediment type because of kinetic barriers associated with low temperatures. © 2015 SETAC.

  3. RDX induces aberrant expression of microRNAs in mouse brain and liver.

    Zhang, Baohong; Pan, Xiaoping


    Although microRNAs (miRNAs) have been found to play an important role in many biological and metabolic processes, their functions in animal response to environmental toxicant exposure are largely unknown. We used hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a common environmental contaminant, as a toxicant stressor to investigate toxicant-induced changes in miRNA expression in B6C3F1 mice and the potential mechanism of RDX-induced toxic action. B6C3F1 mice were fed diets with or without 5 mg/kg RDX for 28 days. After the feeding trials, we isolated RNAs from both brain and liver tissues and analyzed the expression profiles of 567 known mouse miRNAs using microarray and quantitative real-time polymerase chain reaction technologies. RDX exposure induced significant changes in miRNA expression profiles. A total of 113 miRNAs, belonging to 75 families, showed significantly altered expression patterns after RDX exposure. Of the 113 miRNAs, 10 were significantly up-regulated and 3 were significantly down-regulated (p RDX exposure. Specifically, expression of seven miRNAs was up-regulated in the brain but down-regulated in the liver or up-regulated in the liver but down-regulated in the brain (p < 0.01). Many aberrantly expressed miRNAs were related to various cancers, toxicant-metabolizing enzymes, and neurotoxicity. We found a significant up-regulation of oncogenic miRNAs and a significant down-regulation of tumor-suppressing miRNAs, which included let-7, miR-17-92, miR-10b, miR-15, miR-16, miR-26, and miR-181. Environmental toxicant exposure alters the expression of a suite of miRNAs.

  4. Magnetic gold nanoparticles: synthesis, characterization and its application in the delivery of FITC into KG-1 cells.

    Hao, Yuzhi; Song, Steven; Yang, Xiaoyan; Xing, James; Chen, Jie


    In this article, we report a new method-a sonication method to disperse iron oxide nanoparticles into smaller nanoparticles and make gold ions absorb onto the surface or trapped in the micropores of the iron oxide nanoparticles using sonication action. By using quick reduction of ascorbic acid and post-HCI solution treatment, gold covered magnetic nanoparticles (mGNPs) with spherical morphology and uniform size were synthesized in a water solution. The size of the mGNPs was found to be 20-30 nm. Some ideal mGNPs possessed a core-shell structure. The mGNPs were non-cytotoxic and mGNP-fluorescein isothiocyanate (FITC) can enter KG-1 cells when driven by an external magnetic force, which was confirmed by confocal imaging. The confocal image also showed the FITC inside the KG-1 cells was near the nucleus. The fluorescein isothiocyanate (FITC) delivery efficiency is about 100% according to the flow cytometry results.

  5. Molecular dynamics simulations of RDX and RDX-based plastic-bonded explosives.

    Zhu, Wei; Xiao, Jijun; Zhu, Weihua; Xiao, Heming


    Molecular dynamics simulations have been performed to investigate well-known energetic material cyclotrimethylene trinitramine (RDX) crystal and RDX-based plastic-bonded explosives (PBXs) with four typical fluorine-polymers, polyvinylidenedifluoride (PVDF), polychlorotri-fluoroethylene (PCTFE), fluorine rubber (F(2311)), and fluorine resin (F(2314)). The elastic coefficients, mechanical properties, binding energies, and detonation performances are obtained for the RDX crystal and RDX-based PBXs. The results indicate that the mechanical properties of RDX can be effectively improved by blending with a small amount of fluorine polymers and the overall effect of fluorine polymers on the mechanical properties of the PBXs along three crystalline surfaces is (001)>(010) approximately (100) and PVDF is regarded to best improve the mechanical properties of the PBXs on three surfaces. The order of the improvement in the ductibility made by the fluorine polymers on different surfaces is (001) approximately (010)>(100). The average binding energies between different RDX crystalline surfaces and different polymer binders are obtained, and the sequence of the binding energies of the PBXs with the four fluorine polymers on the three different surfaces is varied. Among the polymer binders, PVDF is considered as best one for RDX-based PBXs. The detonation performances of the PBXs decrease in comparison with the pure crystal but are superior to those of TNT.

  6. RDX-Aluminum Interaction-A DFT Study

    Lemi Türker


    Within the constraints of density functional theory (UB3LYP/6‐311+ +G(d ,p)) ,RDX/Al and RDX/2Al composites are investigated ,considering various multiplicity states (singlet and triplet states) .Depending on the localization of Al atom(s) in space and multiplicity of the composite systems ,the structure of RDX undergoes various degrees of perturbations .It has been shown that the presence of Al atoms affects the bond lengths ,electron population as well as the HOMO and LUMO energies and the inter frontier molecular orbital energy gap of RDX .All these perturbations are thought to affect ballistic properties of the ex‐plosive molecule RDX .

  7. Sub-Nanogram Detection of RDX Explosive by Monoclonal Antibodies.

    Ulaeto, David O; Hutchinson, Alistair P; Nicklin, Stephen


    Polyclonal and monoclonal antibodies were raised to protein carrier molecules haptenized with RDX, a major component of many plastic explosives including Semtex. Sera from immunized mice detected RDX protein conjugates in standard ELISA. Clonally purified monoclonal antibodies had detection limits in the sub-ng/mL range for underivatized RDX in competition ELISA. The monoclonal antibodies are not dependent on the presence of taggants added during the manufacturing process, and are likely to have utility in the detection of any explosive containing RDX, or RDX contamination of environmental sites.

  8. Preparation and Characterization of Cyclotrimethylenetrinitramine (RDX) with Reduced Sensitivity.

    Wang, Yuqiao; Li, Xin; Chen, Shusen; Ma, Xiao; Yu, Ziyang; Jin, Shaohua; Li, Lijie; Chen, Yu


    The internal defects and shape of cyclotrimethylenetrinitramine (RDX) crystal are critical parameters for the preparation of reduced sensitivity RDX (RS-RDX). In the current study, RDX was re-crystallized and spheroidized to form the high-quality RDX that was further characterized by purity, apparent density, size distribution, specific surface area, impact sensitivity, and shock sensitivity. The effects of re-crystallization solvent on the growth morphology of RDX crystal were investigated by both theoretical simulation and experiment test, and consistent results were obtained. The high-quality RDX exhibited a high purity (≥99.90%), high apparent density (≥1.811 g/cm³), spherical shape, and relatively low impact sensitivity (6%). Its specific surface area was reduced more than 30%. Compared with conventional RDXs, the high-quality RDX reduced the shock sensitivities of PBXN-109 and PBXW-115 by more than 30%, indicating that it was a RS-RDX. The reduced sensitivity and good processability of the high-quality RDX would be significant in improving the performances of RDX-based PBXs.

  9. Polymorphic Phase Control of RDX-Based Explosives.

    Brady, John J; Argirakis, Brittney L; Gordon, Alexander D; Lareau, Richard T; Smith, Barry T


    The polymorphic phase of 1,3,5-trinitro-1,3,5-triazine (RDX) was examined as a function of mass loading, solvent, and sample deposition technique. When RDX was deposited at a high mass loading, the vibrational modes in the obtained Raman spectra were indicative of concomitant polymorphism as both the α-RDX and β-RDX phases were present. At low mass loadings, only β-RDX was observed regardless of solvent when using the drop cast crystallization method. However, α-RDX (the thermodynamically stable polymorphic phase observed with visible quantities of the explosive) was observed when RDX deposits were dry transferred. Observation of α-RDX was independent of the initial mass loading or the initial deposition solvent when using the dry transfer methodology. These data indicate that the use of the dry transfer preparation method can be used to successfully prepare RDX-based test articles with the α-RDX phase regardless of the solvent used to initially dissolve the RDX, the initial deposition technique, or the mass loading.

  10. Electrolytic redox and electrochemical generated alkaline hydrolysis of hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) in sand columns.

    Gent, David B; Wani, Altaf H; Davis, Jeffrey L; Alshawabkeh, Akram


    Sand-packed horizontal flow columns (5 cm i.d. x 65 cm)l were used in laboratory experiments to simulate in situ electrolytic and alkaline hybrid treatment zone for aqueous phase decomposition of RDX. An upgradient cathode and downgradient anode, spaced 35 cm apart were used to create alkaline reducing conditions followed by oxic, acidic conditions to degrade RDX by combination of alkaline hydrolysis and direct electrolysis. A preliminary experiment (25 mg/L RDX influent) with seepage velocity of 30.5 cm/day and current density of 9.9 A/m2 was used to determine the treatment feasibility and the aqueous products of RDX decomposition. Three additional column experiments (0.5 mg/L RDX influent) under the same conditions as the preliminary column were used to observe the treatment process repeatability and the alkaline treatment zone development. The results demonstrated approximately 95% decomposition of RDX in the column with an applied current density of 9.9 A/m2. Aqueous end-products formate, nitrite, and nitrate were detected in the effluent. Approximately 75% of the RDX was destroyed near the cathode, presumably by electrolysis, with 23% decomposed downstream of the cathode by alkaline hydrolysis. The preliminary column pseudo first order alkaline hydrolysis rate coefficient of 10.7 x 10(-3) min(-1) was used to estimate a treatment zone length less than 100 cm for RDX treatment below the EPA drinking water lifetime health advisory of 0.002 mg/L.

  11. Cancer mode of action, weight of evidence, and proposed cancer reference value for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Sweeney, Lisa M; Okolica, Michelle R; Gut, Chester P; Gargas, Michael L


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, CAS No. 121-82-4) is a component of munitions formulations, and has been detected in groundwater samples collected at various US military sites. Clean up target levels for RDX may be derived based on consideration of acceptable cumulative human exposure as expressed in toxicity reference values. Evaluations of the cancer weight of evidence and possible modes of action (MOA) for RDX-induced cancer were conducted. It was concluded that the available data provide suggestive evidence of human carcinogenic potential for RDX. While a mutagenic/genotoxic MOA for RDX is unlikely, no alterative MOA is strongly supported by the available data. A nonlinear (threshold) approach to the assessment of human cancer risk was recommended, and a recommended chronic cancer reference dose of 0.08mg/kg/day was derived. For comparison only, computations using a linear approach were also conducted, yielding a cancer risk specific dose of 0.000235mg/kg/day for 1 in 10(5) risk; this value is 2.6-fold higher the current US EPA risk specific dose for 1 in 10(5) risk. Thus, cleanup standards based on human health risk from RDX exposure could potentially depend on the willingness of risk managers to accept a nonlinear MOA and nonlinear toxicity risk value derivation. Published by Elsevier Inc.

  12. Properties of RDX-CMDB Propellants Containing Guanidinium Azotetrazolate(GZT)%含偶氮四唑胍的改性双基推进剂性能

    王琼; 刘小刚; 姬月萍; 樊学忠; 蔚红建; 王晗; 张林军


    RDX-CMDB propellants containing guanidinium azotetrazolate(GZT) were prepared by standard cast technique.Properties including energy,combustion,thermal security and the thermal behaviors of RDX-CMDB propellants were studied through theoretical calculations and experimentations.Results indicate that the specific impulse( I5p ),explosion heat(Q) and adiabatic combustion temperature of RDX-CMDB propellants decrease with the replacement of RDX by GZT,and gas volume increases.Replacement of RDX with 15% GZT makes the specific impulse,explosion heat and adiabatic combustion temperature decrease 29.2 s,1248 kJ · kg-1 and 800 K,respectively,and gas output increase 10.73 mol · kg-1.GZT makes RDX-CMDB propellants detonate and deflagrate more easily at high temperature above 200 ℃,but has no obvious influence on thermal security of RDX-CMDB propellants below 100 ℃,For RDX-CMDB propellants without the catalysts( lead and copper composite organic salts),GZT could increase the burning rates and decrease the pressure exponents of propellants,15% replacement of RDX by GZT results in the increase of burning rate by 1 mm · s-1 under 7 MPa and the decrease of pressure exponent from 0.86 to 0.70 under pressure 7 -10 MPa.For RDX-CMDB propellants with the catalyst,GZT decreases the burning rates and increases the pressure exponents of propellants,15% replacement of RDX by GZT increases the pressure exponent from 0.47 to 0.69 under pressure 7 -10 MPa and decrease the burning rate by 3 mm · s-1.The TG experiments of RDX-CMDB propellants containing GZT indicate that a mass loss process corresponding to decomposition of GZT appears in the TG curve.%采用浇铸工艺制备了含偶氮四唑胍盐(GZT)的RDX-CMDB推进剂,系统地研究了含GZT的RDX-CMDB推进剂的能量性能、燃烧性能和热安全性能等.理论计算和实验研究结果表明:RDX-CMDB推进剂的比冲、爆热和燃温随GZT含量的增加而降低,15%的GZT使推进剂的比冲降低了29.2 s

  13. Sustainable Range Management of RDX and TNT by Phytoremediation with Engineered Plants


    tissue was also analyzed. 100 mg plant tissue were collected and freeze-dried, using a Fast Prep 24 (MP Biomedicals, LLC., Solon, USA). Powdered... Prep machine. 1 ml methanol was added per tube, and the tubes vortexed. The tubes were shaken at 100 rpm overnight and centrifuged at 15000 g for 10...with xplA-xplB-nfsI, decreased rapidly to zero . Analysis of the RDX concentrations in the leaves showed that there was no significant reduction in the

  14. Characterization of Cyclohexanone Inclusions in Class 1 RDX


    Characterization of Cyclohexanone Inclusions in Class 1 RDX by Rose A. Pesce-Rodriguez and Stephanie M. Piraino ARL-TR-6962 June 2014...TR-6962 June 2014 Characterization of Cyclohexanone Inclusions in Class 1 RDX Rose A. Pesce-Rodriguez and Stephanie M. Piraino Weapons...3. DATES COVERED (From - To) 12/2012 to 6/2013 4. TITLE AND SUBTITLE Characterization of Cyclohexanone Inclusions in Class 1 RDX 5a. CONTRACT

  15. Studies of thermal dissolution of RDX in TNT melt

    Suvorova, N. A.; Hamilton, V. T.; Oschwald, D. M.; Balakirev, F. F.; Smilowitz, L. B.; Henson, B. F.


    The thermal response of energetic materials is studied due to its importance in issues of material safety and surety. Secondary high explosives which melt before they thermally decompose present challenging systems to model due to the addition of material flow. Composition B is a particularly challenging system due to its multiphase nature with a low melt component (TNT) and a high melt component (RDX). The dissolution of RDX crystals in molten TNT at the temperature below RDX melting point has been investigated using hot stage microscopy. In this paper, we present data on the dissolution rate of RDX crystals in molten TNT as a function of temperature above the TNT melt.

  16. Toxicity of the conventional energetics TNT and RDX relative to new insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

    Stanley, Jacob K; Lotufo, Guilherme R; Biedenbach, James M; Chappell, Pornsawan; Gust, Kurt A


    An initiative within the US military is targeting the replacement of traditional munitions constituents with insensitive munitions to reduce risk of accidental detonation. The purpose of the present study was to comparatively assess toxicity of the traditional munitions constituents 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) with the new insensitive munitions constituents 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO). The following exposure durations were performed with Rana pipiens (leopard frog) tadpoles: TNT and DNAN, 96 h and 28 d; RDX, 10 d and 28 d; NTO, 28 d. The 96-h 50% lethal concentration (LC50) values and 95% confidence intervals for TNT and DNAN were 4.4 mg/L (4.2 mg/L, 4. 7 mg/L) and 24.3 mg/L (21.3 mg/L, 27.6 mg/L), respectively. No significant impacts on survival were observed in the 10-d exposure to RDX up to 25.3 mg/L. Effects on tadpole swimming distance were observed with a lowest-observed-effect concentration (LOEC) of 5.9 mg/L RDX. In the 28-d exposures, the LOECs for survival for TNT, DNAN, and NTO were 0.003 mg/L, 2.4 mg/L, and 5.0 mg/L, respectively. No significant mortality was observed in the RDX chronic 28-d exposure up to the highest treatment level tested of 28.0 mg/L. Neither tadpole developmental stage nor growth was significantly affected in any of the 28-d exposures. Rana pipiens were very sensitive to chronic TNT exposure, with an LOEC 3 orders of magnitude lower than those for insensitive munitions constituents DNAN and NTO.

  17. The Preparation and Properties of RDX-Composition A


    accordingly RDX particles adhere to wax globules and re- tain them in the slurry. The RDX is neither capable of acting as an efficient powder- emulsifier for...prepared by the addition of extra wax and aluminum, plus lecithin , to a rollod Composition A. "ith a total of 12fr wax, such a mixture can be poured, but

  18. Microscopic characterization of defect structure in RDX crystals

    Bouma, R.H.B.; Duvalois, W.; Heijden, A.E.D.M. van der


    Three batches of the commercial energetic material RDX, as received from various production locations and differing in sensitivity towards shock initiation, have been characterized with different microscopic techniques in order to visualize the defect content in these crystals. The RDX crystals are

  19. Preparation and characterization of GA/RDX nanostructured energetic composites



    Graphene aerogel (GA) with nano-porous structure was assembled through the formation of physical cross-links between graphene sheets by a facile sol–gel method and supercritical CO$_2$ drying process. Thenhexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was added and trapped in the nano-porous three-dimensional networks of GA to obtain a novel GA/RDX nanostructured energetic composite. The composition, morphology andstructure of the obtained GA/RDX nanostructured energetic composite were characterized by elemental analysis, scanning electron microscopy, nitrogen sorption tests and X-ray diffraction. Moreover, the thermal decompositioncharacteristic was investigated by thermogravimetry and differential scanning calorimetry. The results showed that GA could be a perfect aerogel matrix for the fabrication of GA/RDX nanostructured energetic composite due to itsunique nano-porous structure and attributes. It was also demonstrated that RDX homogeneously disperses in the asprepared GA/RDX nanostructured energetic composite at nanometric scale. GA showed promising catalytic effects for the thermal decomposition of RDX. After incorporating with GA, the decomposition of RDX was obviously accelerated.

  20. Behavioral and physiological effects of RDX on adult zebrafish.

    Williams, Larry R; Wong, Keith; Stewart, Adam; Suciu, Christopher; Gaikwad, Siddharth; Wu, Nadine; Dileo, John; Grossman, Leah; Cachat, Jonathan; Hart, Peter; Kalueff, Allan V


    1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) is a nitroamine explosive, with common toxic effects including seizures. Here, we explore the behavioral effects of acute RDX exposure in adult zebrafish Danio rerio, a rapidly developing model in neuroscience and neurotoxicology research. Overall, a 30-min exposure to RDX low dose of 0.1 mM evoked behavioral activation in zebrafish, while a higher dose of 1 mM markedly reduced exploration, increased freezing and evoked seizure-like responses (i.e., bouts of hyperactivity, spasms, and corkscrew swimming). Likewise, whole-body cortisol levels were also significantly elevated in fish exposed to 1 mM (but not 0.1 mM) RDX. In line with clinical and animal data, our study demonstrates the dose-dependent behavioral activation and pro-convulsant effects of RDX in zebrafish-based models. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Molecular dynamic simulations on TKX-50/RDX cocrystal.

    Xiong, Shuling; Chen, Shusen; Jin, Shaohua


    Dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) is a newly synthesized energetic material with excellent comprehensive properties. Cyclotrimethylenetrinitramine (RDX) is currently one of the most widely used energetic materials in the world. TKX-50 and RDX supercell models and TKX-50/RDX cocrystal model were constructed based on their crystal cell parameters and the formation mechanism of cocrystal, respectively, then they were simulated by molecular dynamics (MD) simulations. The maximum trigger bond (NNO2) length(Lmax), binding energy (Ebind), radial distribution function (RDF), cohesive energy density(CED) and mechanical properties were simulated at different temperatures based on the simulated equilibrium structures of the models. The simulated results indicate that hydrogen bond and van der Waals force interactions exist in the cocrystal system and the hydrogen bonds are mainly derived from the hydrogen atom of TKX-50 with the oxygen or nitrogen atom of RDX. Moreover, TKX-50/RDX cocrystal structure significantly reduces the sensitivity and improves the thermodynamic stability of RDX, and it also shows better mechanical properties than pure TKX-50 and RDX, indicating that it will vastly expand the application scope of the single compound explosives. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Study on Low Pressure Combustion Characteristic of RDX-CMDB Propellants%RDX-CMDB推进剂低压燃烧性能研究

    田长华; 王琳; 齐晓飞; 刘鹏


    用燃速测试研究了燃烧催化剂(铅盐、铅盐/铜盐、铅盐/铜盐/炭黑)、燃烧稳定剂(CaCO3、TiO2、MgO及A12O3)以及RDX粒径(7μm、21 μm和45 μm)对RDX-CMDB推进剂在低压下[(1~5)MPa]燃烧性能的影响.结果表明,复配体系的燃烧催化剂可有效提高RDX-CMDB推进剂的燃速并降低其压强指数,推进剂燃速随RDX粒径增大而提高,CaCO3可提高推进剂燃速,TiO2、MgO和Al2 O3会导致推进剂燃速降低.

  3. Delayed myelosuppression with acute exposure to hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and environmental degradation product hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) in rats.

    Jaligama, Sridhar; Kale, Vijay M; Wilbanks, Mitchell S; Perkins, Edward J; Meyer, Sharon A


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a widely used munitions compound, and hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), its N-nitroso product of anaerobic microbial nitroreduction, are contaminants of military sites. Previous studies have shown MNX to be the most acutely toxic among the nitroreduced degradation products of RDX and to cause mild anemia at high dose. The present study compares hematotoxicity with acute oral exposure to MNX with parent RDX. Both RDX and MNX caused a modest decrease in blood hemoglobin and ~50% loss of granulocytes (NOAELs=47 mg/kg) in female Sprague-Dawley rats observed 14 days post-exposure. We explored the possibility that blood cell loss observed after 14 days was delayed in onset because of toxicity to bone marrow (BM) progenitors. RDX and MNX decreased granulocyte/macrophage-colony forming cells (GM-CFCs) at 14, but not 7, days (NOAELs=24 mg/kg). The earliest observed time at which MNX decreased GM-CFCs was 10 days post-exposure. RDX and MNX likewise decreased BM burst-forming units-erythroid (BFU-Es) at 14, but not 7, days. Granulocyte-erythrocyte-monocyte-megakaryocyte (GEMM)-CFCs were unaffected by RDX and MNX at 7 days suggesting precursor depletion did not account for GM-CFC and BFU-E loss. MNX added to the culture media was without effect on GM-CFC formation indicating no direct inhibition. Flow cytometry showed no differential loss of BM multilineage progenitors (Thy1.1(+)) or erythroid (CD71(+)) precursors with MNX suggesting myeloid and erythroid lineages were comparably affected. Collectively, these data indicate that acute exposure to both RDX and MNX caused delayed suppression of myelo- and erythropoiesis with subsequent decrease of peripheral granulocytes and erythrocytes. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

    Fuchs, Dominik [Research Group Molecular Neuro-Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Daniel, Volker; Sadeghi, Mahmoud; Opelz, Gerhard [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Naujokat, Cord, E-mail: [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany)


    Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.

  5. Synthesis of Keto-RDX and its Characterizations Calculation%Keto-RDX的合成及性能计算

    Arash Shokrollahi; Abbas Zali; Hamid Reza Pouretedal; Mohammad Hossein Keshavarz


    Keto-RDX was obtained by one-step method with a certain amount of RDX as by-product. The effects of various parameters on high yield were studied. A simple analytical method was also introduced to determine simultaneously Keto-RDX/RDX mole ratio. Some important theoretical characterizations of Keto-RDX such as detonation performance at maximum nominal density and shock sensitivity were determined by new methods and compared with RDX.

  6. Laser-Induced Plasma Chemistry of the Explosive RDX with Various Metals


    UNCLASSIFIED discrimination RDX residue on various metals Effects of substrate on discrimination Motivation Investigated formation of carbon in aluminized -RDX...included: . , . , (99.98%), tin (99.998%) and titanium (99.998%) • numerous metal alloys including brass, lead and steel Differences in the...b. NiCu C 1248 ste,el1761 - steel C 1296 <l Ti 641 o Zn 625 Lead C2417 + RDX ead C2418 + RDX NiCu C1248 + RDX steel 1761 + RDX steel C1296

  7. The Dilution/Crystallization Kinetics of RDX and HMX


    Three thermokinetic equations describing the crystal growth process and two relationships between the parameters and the constants of the kinetic equations are derived. The thermokinetic data of crystal growth processes of RDX and HMX are treated based on the derived equations and relationships. The results show that the exothermic dilution / crystallization processes of RDX and HMX are the first order reaction and accord with the dislocation theory.

  8. Bioaugmentation for Aerobic Bioremediation of RDX Contaminated Groundwater


    columns [8]. Also, aerobic RDX degradation by these Rhodococcus sp. does not produce toxic nitroso end-products. Several other aerobic actinomycete ...degrading activity amont Actinomycete bacteria. Journal of Applied Microbiology, 2011. 110: p. 1449-1459. 16. Fuller, M.E., et al., Transformation of RDX... Marine Ecology Progress Series, 1999. 190: p. 141-153. 27. Weiss, T.H., et al., Effect of bacterial cell shape on transport of bacteria in porous media

  9. Bioaugmentation for Aerobic Bioremediation of RDX-Contaminated Groundwater


    Rhodococcus sp. does not produce toxic nitroso end-products. Several other aerobic actinomycete bacteria [9-13] transform RDX by the cytochrome P450, Horizontal gene transfer (HGT) as a mechanism of disseminating RDX-degrading activity amont Actinomycete bacteria. Journal of Applied...physiological status of bacteria on their transport into permeable sediments. Marine Ecology Progress Series, 1999. 190: p. 141-153. 27. Weiss, T.H

  10. Bioconcentration of TNT and RDX in coastal marine biota.

    Ballentine, Mark; Tobias, Craig; Vlahos, Penny; Smith, Richard; Cooper, Christopher


    The bioconcentration factor (BCF) was measured for 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in seven different marine species of varying trophic levels. Time series and concentration gradient treatments were used for water column and tissue concentrations of TNT, RDX, and their environmentally important derivatives 2-amino-4,6-dintrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). BCF values ranged from 0.0031 to 484.5 mL g(-1) for TNT and 0.023 to 54.83 mL g(-1) for RDX. The use of log K ow value as an indicator was evaluated by adding marine data from this study to previously published data. For the munitions in this study, log K ow value was a good indicator in the marine environment. The initial uptake and elimination rates of TNT and RDX for Fucus vesiculosus were 1.79 and 0.24 h(-1) for TNT and 0.50 and 0.0035 h(-1) for RDX respectively. Biotransformation was observed in all biota for both TNT and RDX. Biotransformation of TNT favored 4-ADNT over 2-ADNT at ratios of 2:1 for F. vesiculosus and 3:1 for Mytilus edulis. Although RDX derivatives were measureable, the ratios of RDX derivatives were variable with no detectable trend. Previous approaches for measuring BCF in freshwater systems compare favorably with these experiments with marine biota, yet significant gaps on the ultimate fate of munitions within the biota exist that may be overcome with the use stable isotope-labeled munitions substrates.

  11. Treatment of RDX and/or HMX Using Mulch Biowalls


    Biodegradation pathways of hexahydro-1,3,5-trinitro-1,3,5- triazine (RDX) by Clostridium acetobutylicum cell-free extract. Chemosphere, 2002. 50: p. 665-671... Fermentative Metabolism, and Reductive Transformation of RDX. ........................... 5 Figure 3. Plan View Schematic of Mulch Wall... fermentative one. This results in the production of a substantial amount of reducing power in the system. The reducing power is “dissipated” by the

  12. An evaluation of the environmental fate and behavior of munitions material (TNT, RDX) in soil and plant systems: Environmental fate and behavior of RDX

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.


    The objective of the present investigation was to elucidate the environmental behavior and fate of hexahydro-1,3,5-trinitro-1,3,5- triazine (RDX), particularly as related to its transport and chemical form in the food chain. To meet this goal, we needed to adapt and develop suitable analytical methodology to fractionate and characterize both RDX and RDX-derived residues in soil and plant matrices. Using the methodology that we developed, we assessed the chemical and physical fate of RDX in soils and plants. In general, the plant availability and plant mobility of RDX is substantially greater than that previously reported for TNT. 30 refs., 27 figs., 26 tabs.

  13. An evaluation of the environmental fate and behavior of munitions material (TNT, RDX) in soil and plant systems: Environmental fate and behavior of RDX

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.


    The objective of the present investigation was to elucidate the environmental behavior and fate of hexahydro-1,3,5-trinitro-1,3,5- triazine (RDX), particularly as related to its transport and chemical form in the food chain. To meet this goal, we needed to adapt and develop suitable analytical methodology to fractionate and characterize both RDX and RDX-derived residues in soil and plant matrices. Using the methodology that we developed, we assessed the chemical and physical fate of RDX in soils and plants. In general, the plant availability and plant mobility of RDX is substantially greater than that previously reported for TNT. 30 refs., 27 figs., 26 tabs.

  14. Electrostaticspray preparation and properties of RDX/DOS composites

    Jian Yao


    Full Text Available A composite explosive based on 1, 3, 5-trinitro-1, 3, 5-triazinane (RDX was prepared by electrostaticspray method with dioctyl sebacate (DOS as desensitizer. After preparation, the particle size and crystal structure were characterized and chemical features, such as chemical bonds, functional groups, thermal decomposition parameters and mechanical sensitivity were investigated as well. In terms of the morphologies of the composites, the particle sizes were in the range of 1–3 μm. Compared with RDX, the crystal types, chemical bonds and functional groups of the RDX/DOS composites were unchanged. The activation energy of the composites was lower than that of raw RDX, and the 3wt % DOS composites had the lowest activation energy. The impact sensitivity and friction sensitivity of the RDX/DOS composites were lower than those of raw RDX, and the 10wt% DOS composites had the highest H50 (125.9 cm and the lowest friction sensitivity (8%.

  15. A method to control the polymorphic phase for RDX-based trace standards

    Brady, John J.; Argirakis, Brittney L.; Gordon, Alexander D.; Lareau, Richard T.; Smith, Barry T.


    The polymorphic phase of 1,3,5-trinitro-1,3,5-triazine (RDX) was examined as a function of mass loading, solvent and sample deposition technique. When RDX was deposited at a high mass loading, the vibrational modes in the obtained Raman spectra were indicative of concomitant polymorphism as both the α and β-RDX phases were present. At low mass loadings, only β-RDX was observed regardless of solvent or mass loading. However, only the bulk phase (i.e., α- RDX) was observed when RDX deposits were dry transferred. Observation of the bulk phase was independent of the initial mass loading or the initial deposition solvent when using the dry transfer methodology. This data demonstrates that the use of the dry transfer preparation method can be used to successfully prepare RDX-based standards with the bulk phase regardless of the solvent used to initially dissolve the RDX, the initial deposition technique, or the mass loading.

  16. Delayed myelosuppression with acute exposure to hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and environmental degradation product hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) in rats

    Jaligama, Sridhar; Kale, Vijay M.; Wilbanks, Mitchell S. [Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209 (United States); Perkins, Edward J. [US Army Engineer Research and Development Center, Vicksburg, MS 39180 (United States); Meyer, Sharon A., E-mail: [Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209 (United States)


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a widely used munitions compound, and hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), its N-nitroso product of anaerobic microbial nitroreduction, are contaminants of military sites. Previous studies have shown MNX to be the most acutely toxic among the nitroreduced degradation products of RDX and to cause mild anemia at high dose. The present study compares hematotoxicity with acute oral exposure to MNX with parent RDX. Both RDX and MNX caused a modest decrease in blood hemoglobin and ∼ 50% loss of granulocytes (NOAELs = 47 mg/kg) in female Sprague–Dawley rats observed 14 days post-exposure. We explored the possibility that blood cell loss observed after 14 days was delayed in onset because of toxicity to bone marrow (BM) progenitors. RDX and MNX decreased granulocyte/macrophage-colony forming cells (GM-CFCs) at 14, but not 7, days (NOAELs = 24 mg/kg). The earliest observed time at which MNX decreased GM-CFCs was 10 days post-exposure. RDX and MNX likewise decreased BM burst-forming units-erythroid (BFU-Es) at 14, but not 7, days. Granulocyte–erythrocyte–monocyte–megakaryocyte (GEMM)-CFCs were unaffected by RDX and MNX at 7 days suggesting precursor depletion did not account for GM-CFC and BFU-E loss. MNX added to the culture media was without effect on GM-CFC formation indicating no direct inhibition. Flow cytometry showed no differential loss of BM multilineage progenitors (Thy1.1{sup +}) or erythroid (CD71{sup +}) precursors with MNX suggesting myeloid and erythroid lineages were comparably affected. Collectively, these data indicate that acute exposure to both RDX and MNX caused delayed suppression of myelo- and erythropoiesis with subsequent decrease of peripheral granulocytes and erythrocytes. Highlights: ► Acute oral exposure to munitions RDX causes myelosuppression. ► Environmental degradation product MNX is comparable in effect. ► RDX and MNX are cytotoxic to both myeloid and erythroid

  17. Long-term efficacy of single-dose treatment with 400 of ivermectin in bancroftian filariasis: results at one year.

    Moulia-Pelat, J P; Glaziou, P; Nguyen, L N; Chanteau, S; Martin, P M; Cartel, J L


    In April 1992, a safety trial was performed with a single dose of ivermectin 400 (IVER 400). In 37 bancroftian filariasis carriers, 6 and 12 months after IVER 400 treatment, the microfilaremia recurrences were 3.2% and 13.5%, respectively. As compared to results from other studies with diethylcarbamazine and IVER at different dosages and periodicities, the dosage of IVER 400 seems the most effective; but a yearly intake might not be sufficient.

  18. NQR Characteristics of an RDX Plastic Explosives Simulant.

    Turecek, J; Schwitter, B; Miljak, D; Stancl, M


    For reliable detection of explosives, a combination of methods integrated within a single measurement platform may increase detection performance. However, the efficient field testing of such measurement platforms requires the use of inexplosive simulants that are detectable by a wide range of methods. Physical parameters such as simulant density, elemental composition and crystalline structure must closely match those of the target explosive. The highly discriminating bulk detection characteristics of nuclear quadrupole resonance (NQR) especially constrain simulant design. This paper describes the development of an inexplosive RDX simulant suited to a wide range of measurement methods, including NQR. Measurements are presented that confirm an RDX NQR response from the simulant. The potential use of the simulant for field testing a prototype handheld NQR-based RDX detector is analyzed. Only modest changes in prototype operation during field testing would be required to account for the use of simulant rather than real explosive.

  19. RDX Binds to the GABAA Receptor–Convulsant Site and Blocks GABAA Receptor–Mediated Currents in the Amygdala: A Mechanism for RDX-Induced Seizures

    Williams, Larry R.; Aroniadou-Anderjaska, Vassiliki; Qashu, Felicia; Finne, Huckelberry; Pidoplichko, Volodymyr; Bannon, Desmond I.; Braga, Maria F. M.


    Background Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a high-energy, trinitrated cyclic compound that has been used worldwide since World War II as an explosive in both military and civilian applications. RDX can be released in the environment by way of waste streams generated during the manufacture, use, and disposal of RDX-containing munitions and can leach into groundwater from unexploded munitions found on training ranges. For > 60 years, it has been known that exposure to high doses of RDX causes generalized seizures, but the mechanism has remained unknown. Objective We investigated the mechanism by which RDX induces seizures. Methods and results By screening the affinity of RDX for a number of neurotransmitter receptors, we found that RDX binds exclusively to the picrotoxin convulsant site of the γ-aminobutyric acid type A (GABAA) ionophore. Whole-cell in vitro recordings in the rat basolateral amygdala (BLA) showed that RDX reduces the frequency and amplitude of spontaneous GABAA receptor–mediated inhibitory postsynaptic currents and the amplitude of GABA-evoked postsynaptic currents. In extracellular field recordings from the BLA, RDX induced prolonged, seizure-like neuronal discharges. Conclusions These results suggest that binding to the GABAA receptor convulsant site is the primary mechanism of seizure induction by RDX and that reduction of GABAergic inhibitory transmission in the amygdala is involved in the generation of RDX-induced seizures. Knowledge of the molecular site and the mechanism of RDX action with respect to seizure induction can guide therapeutic strategies, allow more accurate development of safe thresholds for exposures, and help prevent the development of new explosives or other munitions that could pose similar health risks. PMID:21362589

  20. Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation.

    Cho, Kun-Ching; Fuller, Mark E; Hatzinger, Paul B; Chu, Kung-Hui


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled (15)N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the (15)N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via (13)C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Mineralization of RDX-derived nitrogen to N2 via denitrification in coastal marine sediments.

    Smith, Richard W; Tobias, Craig; Vlahos, Penny; Cooper, Christopher; Ballentine, Mark; Ariyarathna, Thivanka; Fallis, Stephen; Groshens, Thomas J


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common constituent of military explosives. Despite RDX contamination at numerous U.S. military facilities and its mobility to aquatic systems, the fate of RDX in marine systems remains largely unknown. Here, we provide RDX mineralization pathways and rates in seawater and sediments, highlighting for the first time the importance of the denitrification pathway in determining the fate of RDX-derived N. (15)N nitro group labeled RDX ((15)N-[RDX], 50 atom %) was spiked into a mesocosm simulating shallow marine conditions of coastal Long Island Sound, and the (15)N enrichment of N2 (δ(15)N2) was monitored via gas bench isotope ratio mass spectrometry (GB-IRMS) for 21 days. The (15)N tracer data were used to model RDX mineralization within the context of the broader coastal marine N cycle using a multicompartment time-stepping model. Estimates of RDX mineralization rates based on the production and gas transfer of (15)N2O and (15)N2 ranged from 0.8 to 10.3 μmol d(-1). After 22 days, 11% of the added RDX had undergone mineralization, and 29% of the total removed RDX-N was identified as N2. These results demonstrate the important consideration of sediment microbial communities in management strategies addressing cleanup of contaminated coastal sites by military explosives.

  2. Application of (13)C-stable isotope probing to identify RDX-degrading microorganisms in groundwater.

    Cho, Kun-Ching; Lee, Do Gyun; Roh, Hyungkeun; Fuller, Mark E; Hatzinger, Paul B; Chu, Kung-Hui


    We employed stable isotope probing (SIP) with (13)C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving (13)C-labeled RDX, suggesting the presence of microorganisms able to incorporate carbon from RDX or its breakdown products. The clones, residing in Bacteroidia, Clostridia, α-, β- and δ-Proteobacteria, and Spirochaetes, were different from previously described RDX degraders. A parallel set of microcosms was amended with cheese whey and RDX to evaluate the influence of this co-substrate on the RDX-degrading microbial community. Cheese whey stimulated RDX biotransformation, altered the types of RDX-degrading bacteria, and decreased microbial community diversity. Results of this study suggest that RDX-degrading microorganisms in groundwater are more phylogenetically diverse than what has been inferred from studies with RDX-degrading isolates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. 蝎毒多肽对白血病细胞株KG1a干细胞活性的影响%Study on the effects of PESV on the viability of leukemia stem cells line KG1a

    杨向东; 李红玉; 李德冠; 史哲新; 杨文华; 颜田赅; 闫理想; 王兴丽



  4. Bioaccumulation kinetics of the conventional energetics TNT and RDX relative to insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

    Lotufo, Guilherme R; Biedenbach, James M; Sims, Jerre G; Chappell, Pornsawan; Stanley, Jacob K; Gust, Kurt A


    The manufacturing of explosives and their loading, assembling, and packing into munitions for use in testing on training sites or battlefields has resulted in contamination of terrestrial and aquatic sites that may pose risk to populations of sensitive species. The bioaccumulative potential of the conventional explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and of the insensitive munitions (i.e., less shock sensitive) compound 2,4-dinitroanisole (DNAN) were assessed using the Northern leopard frog, Rana pipiens. Trinitrotoluene entering the organism was readily biotransformed to aminodinitrotoluenes, whereas no transformation products were measured for RDX or DNAN. Uptake clearance rates were relatively slow and similar among compounds (1.32-2.19 L kg(-1) h(-1) ). Upon transfer to uncontaminated water, elimination rate was very fast, resulting in the prediction of fast time to approach steady state (5 h or less) and short elimination half-lives (1.2 h or less). A preliminary bioconcentration factor of 0.25 L kg(-1) was determined for the insensitive munitions compound 3-nitro-1,2,4-trizole-5-one (NTO) indicating negligible bioaccumulative potential. Because of the rapid elimination rate for explosives, tadpoles inhabiting contaminated areas are expected to experience harmful effects only if under constant exposure conditions given that body burdens can rapidly depurate preventing tissue concentrations from persisting at levels that may cause detrimental biological effects.

  5. Resistance of Leukemia KG1 a Cells with Positive N-cadherin in Phase G0Against Killing Activity of VP16%N-cadherin阳性白血病KG1a细胞系在G0期抵抗VP16杀伤的作用

    何侃; 于沛; 邢海燕; 李艳; 田征; 王敏; 唐克晶; 饶青


    抗药性是白血病干细胞的重要特征,为探索N-cadherin阳性的白血病细胞耐受化疗药物VP16杀伤作用的机制,本研究以白血病细胞系KGla为研究模型,利用流式细胞术测定N-cadherin阳性和N-cadherin阴性细胞在G0期比例的差异,利用G-CSF诱导KG1a细胞进入细胞周期,观察G0期细胞比例的变化,并测定诱导后KG1a细胞对VP16的敏感性;再利用EGTA抑制N-cadherin介导的细胞间黏附后,观察KG1a细胞耐药性的变化.结果 显示,N-cadherin阳性的KG1a细胞G0期比例高于N-cadherin阴性的细胞;诱导KG1a细胞进入细胞周期后G0期细胞比例明显下降,KG1a细胞对VP16的敏感性显著升高;利用EGTA处理KG1a细胞24小时抑制N-cadherin的作用后,KG1a细胞在G0期比例降低,KG1a细胞对VP16的药物敏感性显著升高.结论:N-cadherin通过介导白血病细胞之间的黏附作用,使白血病细胞处于G0期的静息状态,从而耐受VP16的杀伤作用.%This study was aimed to investigate the methylation status of WTI gene in leukemia cell lines and its relation with expression of WTI gene. The WTI gene was silenced by DNA methylation or histone deacetylation, and the expression of WTI gene was induced by using HDAC inhibitor and/or demethylation agent of DNA. Some leukemia cell lines (U937, HL-60, K562, KG1) were detected by RT-PCR, MS-PCR, restriction analysis, and DNA sequencing. U937 leukemic cells without WTI mRNA expression were incubated with HDAC inhibitor Trichostatin A (TSA) and/or demethylation agent decitabine. The results showed that the U937 cells did not express WTI gene, but HL-60, K562 and KG1 cells hyghly expressed WTI gene; WTI gene was unmethylated in HL-60 cells, but methylated in K562 and U937 cells. WTI expression could be reactivated by co-incubation with TSA and decitabine, but not was observed by using single drug. It is concluded that WTI promoter is methylated in some leukemia cells, however, the methylation can not affect

  6. Development of Biomarkers for Assessing In Situ RDX Biodegradation Potential


    for their financial support. Also, thanks to Dr. Andrea Leeson and the SERDP In Progress Review panel for their annual guidance and advice. Thanks to...digester in Cornwall , Canada (Zhao et al. 2003). In contrast, the RDX degrading Clostridium acetobutylicum (ATCC 824) is a ubiquitous bacteria in

  7. 76 FR 53906 - Availability of Final Toxicological Profile for RDX


    ... profile for public review and comment was published in the Federal Register on August 26, 2010, (75 FR... Service (NTIS), 5285 Port Royal Road, Springfield, Virginia 22161, telephone 1- 800-553-6847. There is a charge for this profile as determined by NTIS. Hazardous substance NTIS Order No. CAS Number RDX...

  8. Development of Biomarkers for Assessing In Situ RDX Biodegradation Potential


    restriction fragment patterns (TRFPs), a rapid, PCR-based method for the comparison of complex bacterial communities. Journal of Microbiological Methods 31,135...chain reaction method for monitoring RDX-degrading bacteria based on the xplA functional gene. Journal of Microbiological Methods 68,267-274

  9. A study of the solvent effect on the morphology of RDX crystal by molecular modeling method.

    Chen, Gang; Xia, Mingzhu; Lei, Wu; Wang, Fengyun; Gong, Xuedong


    Molecular dynamics simulations have been performed to investigate the effect of acetone solvent on the crystal morphology of RDX. The results show that the growth morphology of RDX crystal in vacuum is dominated by the (111), (020), (200), (002), and (210) faces using the BFDH laws, and (111) face is morphologically the most important. The analysis of surface structures of RDX crystal indicates that (020) face is non-polar, while (210), (111), (002), and (200) faces are polar among which (210) face has the strongest polarity. The interaction between acetone solvent and each RDX crystal face is different, and the order of binding energy on these surfaces is (210) > (111) > (002) > (200) > (020). The analysis of interactions among RDX and acetone molecules reveal that the system nonbond interactions are primary strong van der Waals and electrostatic interactions containing π-hole interactions, the weak hydrogen bond interactions are also existent. The effect of acetone on the growth of RDX crystal can be evaluated by comparing the binding energies of RDX crystalline faces. It can be predicted that compared to that in vacuum, in the process of RDX crystallization from acetone, the morphological importance of (210) face is increased more and (111) face is not the most important among RDX polar surfaces, while the non-polar (020) face probably disappears. The experimentally obtained RDX morphology grown from acetone is in agreement with the theoretical prediction.

  10. Study on the Functional Expression of P2X7 Receptor in Human Leukemic Cell Line KG1a%人白血病细胞系KG1a中P2X7受体的表达和功能研究

    张秀军; 孟丽君



  11. Shock tube propellant reactions: Ignition of M-9 and catalysis of RDX

    Cohen, A.; Decker, L. J.


    The preliminary results of shock tube experiments to study RDX catalysis are presented. It is shown that using N2 as the test gas (P approximately equal to 90 KPa, T bar approximately equal to 650K), the replacement of RDX powder with NaBH4 (20% by weight) leads to a large increase in the amount of RDX reacting and a small decrease in ignition delays T sub i. It is further shown that higher temperatures due to exothermic pyrolysis reactions of NaBH4 are not responsible for these effects. Replacement of N2 by NO2 (10% by volume) in the environment of RDX powders (T bar approximately equal to 650K, P = 90-400 KPa) leads to an increase in T sub i and T sub i is directly proportional to NO2 pressure. Inhibition appears to be initiated by reactions between NO2 and either RDX or the RDX decomposition products.

  12. Biotransformation of RDX and HMX by Anaerobic Granular Sludge with Enriched Sulfate and Nitrate.

    An, Chunjiang; Shi, Yarong; He, Yanling; Huang, Guohe; Liu, Yonghong; Yang, Shucheng


    RDX and HMX are widely used energetic materials and they are recognized as environmental contaminants at numerous locations. The present study investigated the biotransformation of RDX and HMX by anaerobic granular sludge under sulfate- and nitrate-enriched conditions. The results showed that RDX and HMX could be transformed by anaerobic granular sludge when nitrate was present. However, the biotransformation of RDX and HMX was negatively influenced, especially with high nitrate concentrations. Sulfate-enriched conditions were more favorable for the removal of ammunition compounds by anaerobic granular sludge than nitrate-enriched conditions. The removal of RDX and HMX under both nitrate- and sulfate-enriched conditions was facilitated by the use of glucose as additional substrate. This knowledge may help identify factors required for rapid removal of RDX and HMX in high-rate bioreactors. These results can also be applied to devise an appropriate and practical biological treatment strategy for explosive contaminated wastewater.

  13. Shock tube propellant reactions: Ignition of M-9 and catalysis of RDX

    Cohen, A.; Decker, L. J.


    The preliminary results of shock tube experiments to study RDX catalysis are presented. It is shown that using N2 as the test gas (P approximately equal to 90 KPa, T bar approximately equal to 650K), the replacement of RDX powder with NaBH4 (20% by weight) leads to a large increase in the amount of RDX reacting and a small decrease in ignition delays T sub i. It is further shown that higher temperatures due to exothermic pyrolysis reactions of NaBH4 are not responsible for these effects. Replacement of N2 by NO2 (10% by volume) in the environment of RDX powders (T bar approximately equal to 650K, P = 90-400 KPa) leads to an increase in T sub i and T sub i is directly proportional to NO2 pressure. Inhibition appears to be initiated by reactions between NO2 and either RDX or the RDX decomposition products.

  14. Evaluation of functionalized isoreticular metal organic frameworks (IRMOFs) as smart nanoporous preconcentrators of RDX

    Xiong, Ruichang [University of Tennessee, Knoxville (UTK); Odbadrakh, Khorgolkhuu [ORNL; Michalkova, Andrea [Jackson State University; Luna, Johnathan P. [University of Tennessee, Knoxville (UTK); Petrova, Tetyana [Jackson State University; Keffer, David J. [University of Tennessee, Knoxville (UTK); Nicholson, Don M [ORNL; Fuentes-Cabrera, Miguel A [ORNL; Lewis, James [West Virginia University; Leszczynski, Jerzy [Computational Center for Molecular Structure and Interactions, Jackson, MS


    Classical molecular dynamics (MD) and Grand Canonical Monte Carlo (GCMC) simulations were used to generate self-diffusivities, adsorption isotherms and density distributions for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in five isoreticular metal-organic frameworks (IRMOFs), which varied in the cage size and in the presence and location of amine groups. These simulations were performed at room temperature (300 K) and low pressures (up to 1 ppm RDX). The atomic charges required for MD and GCMC simulations were calculated from quantum mechanical (QM) calculations using two different charge generation methods - Loewdin Population Analysis and Natural Bond Orbital Analysis. Both charge sets show that the presence of amine groups increases the amount of RDX adsorbed. The cage size and the location of amine groups also affect the loading of RDX. The amount of RDX adsorbed is correlated with the energy of adsorption. The activation energy for diffusion of RDX is not positively correlated with the energy of adsorption. The density distributions identify the location of the adsorption sites of RDX-exclusively in the big cage around the metal complex vertices and between benzene rings. In the absence of amine groups on the framework, one of nitro groups on RDX interacts closely with the metal complex. In the IRMOFs functionalized with amine groups, a second nitro group of the RDX interacts with an amine group, enhancing adsorption. With regard to the application as a smart nanoporous preconcentrator, these IRMOFs are found to concentrate RDX up to 3000 times compared to the gas phase, on a volumetric basis. From a simple Langmuir estimation, the selectivity of RDX over butane is up to 5000. The diffusion of RDX is sufficiently high for real time sensor applications. These results indicate IRMOFs can be tailored with functional groups to be highly selective nanoporous preconcentrators.

  15. The Effect of RDX Crystal Defect Structure on Mechanical Response of a Polymer-Bonded Explosive


    deformation [a] R. H. B. Bouma Department Process Instrumentation and Design TNO, Organisation for Applied Scientific Research P.O. Box 6012 2600 JA, Delft, The...DOI: 10.1002/prep.201500222 The Effect of RDX Crystal Defect Structure on Mechanical Response of a Polymer-Bonded Explosive Richard H. B. Bouma[a...systematically varied by using three different qualities of Class I RDX. The effect of internal defect structure of the RDX crystal on the shock

  16. MicroRNA and messenger RNA profiling reveals new biomarkers and mechanisms for RDX induced neurotoxicity.

    Deng, Youping; Ai, Junmei; Guan, Xin; Wang, Zhaohui; Yan, Bin; Zhang, Daqin; Liu, Chang; Wilbanks, Mitch S; Escalon, Barbara Lynn; Meyers, Sharon A; Yang, Mary Qu; Perkins, Edward J


    RDX is a well-known pollutant to induce neurotoxicity. MicroRNAs (miRNA) and messenger RNA (mRNA) profiles are useful tools for toxicogenomics studies. It is worthy to integrate MiRNA and mRNA expression data to understand RDX-induced neurotoxicity. Rats were treated with or without RDX for 48 h. Both miRNA and mRNA profiles were conducted using brain tissues. Nine miRNAs were significantly regulated by RDX. Of these, 6 and 3 miRNAs were up- and down-regulated respectively. The putative target genes of RDX-regulated miRNAs were highly nervous system function genes and pathways enriched. Fifteen differentially genes altered by RDX from mRNA profiles were the putative targets of regulated miRNAs. The induction of miR-71, miR-27ab, miR-98, and miR-135a expression by RDX, could reduce the expression of the genes POLE4, C5ORF13, SULF1 and ROCK2, and eventually induce neurotoxicity. Over-expression of miR-27ab, or reduction of the expression of unknown miRNAs by RDX, could up-regulate HMGCR expression and contribute to neurotoxicity. RDX regulated immune and inflammation response miRNAs and genes could contribute to RDX- induced neurotoxicity and other toxicities as well as animal defending reaction response to RDX exposure. Our results demonstrate that integrating miRNA and mRNA profiles is valuable to indentify novel biomarkers and molecular mechanisms for RDX-induced neurological disorder and neurotoxicity.

  17. A comparative study of microbial communities in four soil slurries capable of RDX degradation using illumina sequencing.

    Jayamani, Indumathy; Cupples, Alison M


    The nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has contaminated many military sites. Recently, attempts to remediate these sites have focused on biostimulation to promote RDX biodegradation. Although many RDX degrading isolates have been obtained in the laboratory, little is known about the potential of microorganisms to degrade this chemical while existing in a soil community. The current study examined and compared the RDX degrading communities in four soil slurries to elucidate the potential of natural systems to degrade this chemical. These soils were selected as they had no previous exposure to RDX, therefore their microbial communities offered an excellent baseline to determine changes following RDX degradation. High throughput sequencing was used to determine which phylotypes experienced an increase in relative abundance following RDX degradation. For this, total genomic DNA was sequenced from (1) the initial soil, (2) soil slurry microcosms following RDX degradation and (3) control soil slurry microcosms without RDX addition. The sequencing data provided valuable information on which phylotypes increased in abundance following RDX degradation compared to control microcosms. The most notable trend was the increase in abundance of Brevundimonas and/or unclassified Bacillaceae 1 in the four soils studied. Although isolates of the family Bacillaceae 1 have previously been linked to RDX degradation, isolates of the genus Brevundimonas have not been previously associated with RDX degradation. Overall, the data suggest these two phylotypes have key roles in RDX degradation in soil communities.

  18. Laser Ignition Characteristics of RDX-CMDB Propellants%RDX-CMDB推进剂激光点火特性

    郝海霞; 裴庆; 南宝江; 张衡; 肖立柏; 赵凤起


    采用CO2激光点火的方法研究了双基推进剂SQ-2和RDX-CMDB推进剂在不同热流密度作用下的点火特性,探讨了RDX含量、Al粉和燃烧催化剂对RDX-CMDB推进剂点火性能的影响.实验结果表明,SQ-2和RDX-CMDB推进剂(含Al粉的配方除外)的点火延迟时间随热流密度增加而递减,且热流密度较高时,点火延迟时间变化趋缓.RDX-CMDB推进剂中RDX含量、Al粉和催化剂对其点火延迟时间的影响与热流密度大小有关.在较低热流密度(51.5 W·cm-2)时,除Al粉使推进剂的点火延迟时间变长以外,其他组分对点火延迟时间的影响则不大;在较高热流密度(102 W·cm-2和153 W·cm-2)时,试样的点火延迟时间随着RDX含量的增加而变长,Al粉和催化剂的加入对点火过程和点火延迟时间均有较大影响.%Laser ignition characteristics of double-based (DB) propellant SQ-2 and RDX-CMDB propellants were studied by CO2 laser ignition at different laser fluxes.The effects of content of RDX,Al powder and burning catalysts on ignition characteristics of RDXCMDB were discussed.Results show that the laser ignition delay time of DB propellant SQ-2 and RDX-CMDB propellants except the sample containing Al powder becomes shorter with the heat fluxes increasing, and its change slows down.The influence of the content of RDX,the additives of Al powder and the burning catalysts on the ignition delay time was related with the laser fluxes.The content of other components had little effect on the laser ignition delay time of propellants.Al powder could prolong the delay time at lower heat fluxes,and the delay time increased with increasing of the content of RDX,and Al powder and the catalysts in the propellant had both great influence on the laser ignition process and the delay time of the propellants at the higher heat fluxes.

  19. Riboflavin-mediated RDX transformation in the presence of Shewanella putrefaciens CN32 and lepidocrocite.

    Bae, Sungjun; Lee, Yoonhwa; Kwon, Man Jae; Lee, Woojin


    The potential of riboflavin for the reductive degradation of a cyclic nitramine, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), was investigated in the presence of lepidocrocite and/or Shewanella putrefaciens CN32. RDX reduction by CN32 alone or CN32 with lepidocrocite was insignificant, while 110 μM RDX was completely reduced by CN32 with riboflavin in 78 h. The transformation products identified included nitroso metabolites, formaldehyde, and ammonium, indicating the ring cleavage of RDX. UV and visible light analysis revealed that riboflavin was microbially reduced by CN32, and that the reduced riboflavin was linked to the complete degradation of RDX. In the presence of both CN32 and lepidocrocite (γ-FeOOH), 100 μM-riboflavin increased the rate and extent of Fe(II) production as well as RDX reduction. An abiotic study also showed that Fe(II)-riboflavin complex, and Fe(II) adsorbed on lepidocrocite, reduced RDX by 48% and 21%, respectively. The findings in this study suggest that riboflavin-mediated RDX degradation pathways in subsurface environments are diverse and complex. However, riboflavin, either from bacteria or exogenous sources, can significantly increase RDX degradation. This will provide a sustainable clean-up option for explosive-contaminated subsurface environments. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Molecular dynamics study of the structures and properties of RDX/GAP propellant.

    Li, Miaomiao; Li, Fengsheng; Shen, Ruiqi; Guo, Xiaode


    Molecular dynamics simulations have been performed to investigate well-known energetic material cyclotrimethylene trinitramine (RDX) crystal, glycidyl azide polymer (GAP) and RDX/GAP propellant. The results show that the binding energies on different crystalline surface of RDX change in the order of (0 1 0) > (1 0 0) > (0 0 1). The interactions between RDX and GAP have been analyzed by means of pair correlation functions. The mechanical properties of RDX/GAP propellant, i.e., elastic coefficients, modulus, Cauchy pressure, and Poisson's ratio, etc., have been obtained. It is found that mechanical properties are effectively improved by adding some amounts of GAP polymer, and the overall effect of GAP on three crystalline surfaces of RDX changes in the order of (1 0 0) > (0 1 0) > (0 0 1). The energetic properties of RDX/GAP propellant have also been calculated and the results show that compared with the pure RDX crystal, the standard theoretical specific impulse (I(sp)) of RDX/GAP propellant decrease, but they are still superior to those of double base propellant. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Identification of high explosive RDX using terahertz imaging and spectral fingerprints

    Liu, Jia; Fan, Wen-Hui; Chen, Xu; Xie, Jun


    We experimentally investigated the spectral fingerprints of high explosive cyclo-1,3,5- trimethylene-2,4,6-trinitramine (RDX) in terahertz frequency region. A home-made terahertz time-domain spectroscopy ranging from 0.2 THz∼ 3.4 THz was deployed. Furthermore, two sample pellets (RDX pellet and polyethylene pellet), which were concealed in an opaque envelop, could be identified by using terahertz pulse imaging system. For the purpose of distinguishing the RDX between two pellets, we further calculated the THz frequency -domain map using its spectral fingerprints. It is demonstrated that the high explosive RDX could similarly be identified using terahertz frequency-domain imaging.

  2. Ultra dispersed mixture of PETN and RDX for explosive welding

    Ten, K. A.; Pruuel, E. R.; Kashkarov, A. O.; Rubtsov, I. A.; Spirin, I. A.; Mikhailov, A. L.; Shekhtman, L. I.; Zhulanov, V. V.; Deribas, A. A.


    Mixed formulations of ultrafine PETN+soda and RDX+soda have low detonation velocity and small critical diameters, which makes them attractive for application to new technological processes, such as welding explosion [1]. The above properties of these formulations are due to the use of nanopowders of PETN and RDX along with a phlegmatizing agent of sodium bicarbonate. The detonation parameters of these mixtures were studied using synchrotron radiation from the VEPP-3 accelerator (Budker Institute of Nuclear Physics). Techniques we developed were applied to the measurement of density distribution in the detonation front and the width of the reaction zone, as well as volume distribution of pressure, density and spread velocities in detonation of cylindrical charges.

  3. RDX-based nanocomposite microparticles for significantly reduced shock sensitivity

    Qiu Hongwei, E-mail: [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Stepanov, Victor; Di Stasio, Anthony R. [U.S. Army - Armament Research, Development, and Engineering Center, Picatinny, NJ 07806 (United States); Chou, Tsengming; Lee, Woo Y. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)


    Cyclotrimethylenetrinitramine (RDX)-based nanocomposite microparticles were produced by a simple, yet novel spray drying method. The microparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and high performance liquid chromatography (HPLC), which shows that they consist of small RDX crystals ({approx}0.1-1 {mu}m) uniformly and discretely dispersed in a binder. The microparticles were subsequently pressed to produce dense energetic materials which exhibited a markedly lower shock sensitivity. The low sensitivity was attributed to small crystal size as well as small void size ({approx}250 nm). The method developed in this work may be suitable for the preparation of a wide range of insensitive explosive compositions.

  4. Photocatalysis for the destruction of aqueous TNT, RDX, and HMX

    Showalter, S.K.; Prairie, M.R.; Stange, B.M.; Rodacy, P.J.; Leslie, P.K.


    The photo-destruction of the high explosives HMX, RDX and TNT was investigated using two systems (ozone versus titanium dioxide), two reactors (pot vs annular reactor), and two types of lamps (1000 Watt Hg-Xe vs 25 Watt LP Hg). A mass balance was performed on reactions executed under pseudo-solar conditions, and relative reaction rates and products were compared for ozone and titanium dioxide based processes. The ratios of relative product formation is also discussed. Results show that there was little difference in the reactions performed in the annular reactor when either ozone or titanium oxide were used. The chemistry of RDX and HMX are very similar, as expected. Future work involving the mechanism is also discussed.

  5. Electronic excitation energies in crystals of PETN, RDX and HMX

    Mukhanov, A. E.


    The key role in the model of detonation based on metallization of an explosive plays a fundamental band gap of a molecular crystal. For determining it in a shocked crystal prerequisite calculation for perfect PETN, RDX, and HMX is performed at 0K. Densities of states for these explosives are obtained and fundamental gaps are determined. Calculations are done within the framework of the Density Functional Theory and its planewave and pseudopotential implementation in the ABINIT package.

  6. Synthesis of RDX by nitrolysis of hexamethylenetetramine in fluorous media.

    Yi, Wen-Bin; Cai, Chun


    Perfluorooctanesulfonic acid (CF(3)(CF(2))(7)SO(3)H, PfOS) catalyses the highly efficient nitrolysis of hexamethylenetetramine in fluorous media, affording high yield of explosive RDX. The reaction can be carried out at room temperature in the absence of acetic anhydride and produces smaller amounts of waste acid and nitrate than in traditional process. The fluorous phase containing catalyst could be easily and efficiently recovered for reuse by simple phase separation.

  7. Binding of RDX to Cell Wall Components of Pinus sylvestris and Picea glauca and Three-Year Mineralisation Study of Tissue-Associated RDX Residues.

    Schoenmuth, Bernd; Schenke, Detlef; Scharnhorst, Tanja; Combrinck, Sandra; McCrindle, Robert I; Mueller, Jakob O; Büttner, Carmen; Pestemer, Wilfried


    Contamination of soils with the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, Research Department Explosive) as a result of military applications is a large-area problem globally. Since coniferous trees dominate the vegetation of large areas of military land in Central Europe, particularly in Germany, the long-term fate of (14)C-RDX in the conifers Scots pine and Dwarf Alberta spruce was studied. Acetic acid was the most effective solvent for the removal of extractable RDX residues from homogenates of RDX-laden tree material (85%, 80-90% and 64-80% for roots, wood and needles, respectively). On average, only a fifth of RDX-derived (14)C was bound in non-extractable residues (NER). Within the main cell wall compartments, lignin was the dominant binding site for NER (needles: 32-62%; roots: 38-42%). Hemicellulose (needles: 11-18%; roots: 6-11%) and cellulose (needles: 12-24%; roots: 1-2%) were less involved in binding and a considerable proportion of NER (needles: 15-24%; roots: 59-51%) was indigestible. After three-year incubation in rot chambers, mineralisation of tree-associated (14)C-RDX to (14)CO2 clearly dominated the mass balance in both tree species with 48-83%. 13-33% of (14)C-RDX-derived radioactivity remained in an unleachable form and the remobilisation by water leaching was negligible (< 2%).

  8. Electron shuttle-stimulated RDX mineralization and biological production of 4-nitro-2,4-diazabutanal (NDAB) in RDX-contaminated aquifer material.

    Kwon, Man Jae; Finneran, Kevin T


    The potential for extracellular electron shuttles to stimulate RDX biodegradation was investigated with RDX-contaminated aquifer material. Electron shuttling compounds including anthraquinone-2,6-disulfonate (AQDS) and soluble humic substances stimulated RDX mineralization in aquifer sediment. RDX mass-loss was similar in electron shuttle amended and donor-alone treatments; however, the concentrations of nitroso metabolites, in particular TNX, and ring cleavage products (e.g., HCHO, MEDINA, NDAB, and NH(4) (+)) were different in shuttle-amended incubations. Nitroso metabolites accumulated in the absence of electron shuttles (i.e., acetate alone). Most notably, 40-50% of [(14)C]-RDX was mineralized to (14)CO(2) in shuttle-amended incubations. Mineralization in acetate amended or unamended incubations was less than 12% within the same time frame. The primary differences in the presence of electron shuttles were the increased production of NDAB and formaldehyde. NDAB did not further degrade, but formaldehyde was not present at final time points, suggesting that it was the mineralization precursor for Fe(III)-reducing microorganisms. RDX was reduced concurrently with Fe(III) reduction rather than nitrate or sulfate reduction. Amplified 16S rDNA restriction analysis (ARDRA) indicated that unique Fe(III)-reducing microbial communities (β- and γ-proteobacteria) predominated in shuttle-amended incubations. These results demonstrate that indigenous Fe(III)-reducing microorganisms in RDX-contaminated environments utilize extracellular electron shuttles to enhance RDX mineralization. Electron shuttle-mediated RDX mineralization may become an effective in situ option for contaminated environments.

  9. Metagenomic insights into the RDX-degrading potential of the ovine rumen microbiome.

    Robert W Li

    Full Text Available The manufacturing processes of royal demolition explosive (RDX, or hexahydro-1,3,5-trinitro-1,3,5-triazine, have resulted in serious water contamination. As a potential carcinogen, RDX can cause a broad range of harmful effects to humans and animals. The ovine rumen is capable of rapid degradation of nitroaromatic compounds, including RDX. While ruminal RDX-degrading bacteria have been identified, the genes and pathways responsible for RDX degradation in the rumen have yet to be characterized. In this study, we characterized the metabolic potential of the ovine rumen using metagenomic approaches. Sequences homologous to at least five RDX-degrading genes cloned from environmental samples (diaA, xenA, xenB, xplA, and xplB were present in the ovine rumen microbiome. Among them, diaA was the most abundant, likely reflective of the predominance of the genus Clostridium in the ovine rumen. At least ten genera known to harbor RDX-degrading microorganisms were detectable. Metagenomic sequences were also annotated using public databases, such as Pfam, COG, and KEGG. Five of the six Pfam protein families known to be responsible for RDX degradation in environmental samples were identified in the ovine rumen. However, increased substrate availability did not appear to enhance the proliferation of RDX-degrading bacteria and alter the microbial composition of the ovine rumen. This implies that the RDX-degrading capacity of the ovine rumen microbiome is likely regulated at the transcription level. Our results provide metagenomic insights into the RDX-degrading potential of the ovine rumen, and they will facilitate the development of novel and economic bioremediation strategies.

  10. Metagenomic insights into the RDX-degrading potential of the ovine rumen microbiome.

    Li, Robert W; Giarrizzo, Juan Gabriel; Wu, Sitao; Li, Weizhong; Duringer, Jennifer M; Craig, A Morrie


    The manufacturing processes of royal demolition explosive (RDX), or hexahydro-1,3,5-trinitro-1,3,5-triazine, have resulted in serious water contamination. As a potential carcinogen, RDX can cause a broad range of harmful effects to humans and animals. The ovine rumen is capable of rapid degradation of nitroaromatic compounds, including RDX. While ruminal RDX-degrading bacteria have been identified, the genes and pathways responsible for RDX degradation in the rumen have yet to be characterized. In this study, we characterized the metabolic potential of the ovine rumen using metagenomic approaches. Sequences homologous to at least five RDX-degrading genes cloned from environmental samples (diaA, xenA, xenB, xplA, and xplB) were present in the ovine rumen microbiome. Among them, diaA was the most abundant, likely reflective of the predominance of the genus Clostridium in the ovine rumen. At least ten genera known to harbor RDX-degrading microorganisms were detectable. Metagenomic sequences were also annotated using public databases, such as Pfam, COG, and KEGG. Five of the six Pfam protein families known to be responsible for RDX degradation in environmental samples were identified in the ovine rumen. However, increased substrate availability did not appear to enhance the proliferation of RDX-degrading bacteria and alter the microbial composition of the ovine rumen. This implies that the RDX-degrading capacity of the ovine rumen microbiome is likely regulated at the transcription level. Our results provide metagenomic insights into the RDX-degrading potential of the ovine rumen, and they will facilitate the development of novel and economic bioremediation strategies.

  11. Study on the thermal decomposition behavior of RDX/AP/HTPB propellant%RDX/AP/HTPB推进剂热分解特性研究

    陈沛; 赵凤起; 阴翠梅



  12. Zero-valent iron pretreatment for enhancing the biodegradability of RDX.

    Oh, Seok-Young; Chiu, Pei C; Kim, Byung J; Cha, Daniel K


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (C3H6N3(NO2)3, royal demolition explosive or RDX) is a common nitramine explosive and one of the major constituents in wastewaters from ammunitions plants. The objective of this study is to investigate zero-valent iron (Fe0) pretreatment for enhancing the biodegradability of recalcitrant RDX. It was hypothesized that iron pretreatment can reductively transform RDX to products that are more amenable to biological treatment processes such as activated sludge. Results of batch and column experiments showed rapid and complete removal of RDX by Fe0 regardless of the buffering capacity. Formaldehyde (HCHO), a major reduction product of RDX, was readily biodegraded by a mixed culture. Respirometric data indicate that iron-treated RDX solution exerted substantially higher biochemical oxygen demand (BOD) than untreated RDX solution. We propose that an integrated iron reduction-activated sludge process may be a feasible option for treating RDX-laden wastewater.

  13. On the reliability of sensitivity test methods for submicrometer-sized RDX and HMX particles

    Radacsi, N.; Bouma, R.H.B.; Krabbendam-La Haye, E.L.M.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der


    Submicrometer-sized RDX and HMX crystals were produced by electrospray crystallization and submicrometer-sized RDX crystals were produced by plasma-assisted crystallization. Impact and friction sensitivity tests and ballistic impact chamber tests were performed to determine the product sensitivity.

  14. Study on the effect of RDX content on the properties of nitramine propellant

    Fen ZHANG


    Full Text Available Four kinds of nitroamine propellants with different RDX contents (10%, 20%, 30% and 40% were prepared to study the effect of RDX content on the mechanical properties and combustion properties of nitroamine propellant. The mechanical properties and combustion properties of nitroamine propellant at the normal temperature (20 °C and low temperature (−40 °C were test by using impact testing machine, drop hammer impact test machine and closed bomb vessel. The test results show that the impact strength of 30% RDX-contained nitramine propellant is maximum, but 40% RDX-contained nitramine propellant has the minimum impact strength. And the crushing height of propellant with 20% RDX-contained was the highest, but the crushing height of propellant with 40% RDX-contained the lowest. With the increase in RDX content in nitramine propellant, the energy of nitramine propellant increases and its burning rate reduces, but 40% RDX-contained nitramine propellant did not meet this trend at the low temperature because of its poor mechanical properties.

  15. Regional Exchanges of Information through Intermediate Linkages Affiliated with SEAs: The Research and Development Exchange (RDx).

    Kronkosky, Preston C.

    The Research and Development Exchange (RDx) is a network of eight regional educational laboratories, one university-based research and development center, and a consortium of seven state education agencies working to support state and local school improvement efforts. The RDx has four goals, designed to support dissemination and school improvement…

  16. Confocal scanning laser microscopic study of the RDX defect structure in deformed polymer-bonded explosives

    Heijden, A.E.D.M. van der; Bouma, R.H.B.


    The influence of an explosion-driven deformation on the defect structure in RDX crystals embedded in a polymer-bonded explosive was investigated by means of confocal scanning laser microscopy. The images were compared to the defect structure in the as-received RDX grades, embedded

  17. The effect of RDX crystal defect structure on mechanical response of a polymer-bonded explosive

    Bouma, R.H.B.; Heijden, A.E.D.M. van der


    An explosive composition, derived from AFX-757, was systematically varied by using three different qualities of Class I RDX. The effect of internal defect structure of the RDX crystal on the shock sensitivity of a polymer bonded explosive is generally accepted (Doherty and Watt, 2008). Here the

  18. Metagenomic insights into RDX-degrading potential of the ovine rumen microbiome

    The ovine rumen is capable of rapid degradation of nitroaromatic compounds, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). While ruminal RDX-degrading bacteria have been identified, genes and biological pathways responsible for the biochemical processes in the rumen have yet to be character...

  19. On the reliability of sensitivity test methods for submicrometer-sized RDX and HMX particles

    Radacsi, N.; Bouma, R.H.B.; Krabbendam-La Haye, E.L.M.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der


    Submicrometer-sized RDX and HMX crystals were produced by electrospray crystallization and submicrometer-sized RDX crystals were produced by plasma-assisted crystallization. Impact and friction sensitivity tests and ballistic impact chamber tests were performed to determine the product sensitivity.

  20. Toxicities of TNT and RDX to the Earthworm Eisenia fetida in Five Soils with Contrasting Characteristics


    Monteil-Rivera et al., 2009). Abiotic reactions include alkaline hydrolysis, photolysis, and reduction by iron. Degradation of TNT by soil ...2 TOXICITIES OF TNT AND RDX TO THE EARTHWORM EISENIA FETIDA IN FIVE SOILS ...3. DATES COVERED (From - To) Apr 2001 – Nov 2004 4. TITLE AND SUBTITLE Toxicities of TNT and RDX to the Earthworm Eisenia fetida in Five Soils

  1. Carbon and nitrogen isotope ratios of factory-produced RDX and HMX.

    Howa, John D; Lott, Michael J; Chesson, Lesley A; Ehleringer, James R


    RDX and HMX are explosive compounds commonly used by the military and also occasionally associated with acts of terrorism. The isotopic characterization of an explosive can be a powerful approach to link evidence to an event or an explosives cache. We sampled explosive products and their reactants from commercial RDX manufacturers that used the direct nitration and/or the Bachmann synthesis process, and then analyzed these materials for carbon and nitrogen isotope ratios. For manufacturers using the Bachmann process, RDX (13)C enrichment relative to the hexamine substrate was small (+0.9‰) compared to RDX produced using the direct nitration process (+8.2‰ to +12.0‰). RDX (15)N depletion relative to the nitrogen-containing substrates (-3.6‰) was smaller in the Bachmann process than in the direct nitration process (-12.6‰ to -10.6‰). The sign and scale of these differences agree with theorized mechanisms of mass-dependent fractionation. We also examined the isotopic relationship between RDX and HMX isolated from explosive samples. The δ(13)C and δ(15)N values of RDX generally matched those of the HMX with few exceptions, most notably from a manufacturer known to make RDX using two different synthesis processes. The range in δ(13)C values of RDX in a survey of 100 samples from 12 manufacturers spanned 33‰ while the range spanned by δ(15)N values was 26‰; these ranges were much greater than any previously published observations. Understanding the relationship between products and reactants further explains the observed variation in industrially manufactured RDX and can be used as a diagnostic tool to analyze explosives found at a crime scene. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Addition of RDX/HMX on the Ignition Behaviour of Boron-Potassium Nitrate Pyrotechnic Charge

    K.R. Rani Krishnan


    Full Text Available Boron-potassium nitrate (B-KNO3 (25/75 is a well-known pyrotechnic composition whichfinds application as energy-release system for small-calibre rockets and pyrogen igniters forlarger motors. The decomposition of the oxidiser in this composition is endothermic which canbe activated by the addition of high explosives, which decompose exothermically. This paperdescribes the influence of two nitramine explosives, RDX and HMX, on the ignition characteristicsof B-KNO3 composition using thermogravimetry, differential scanning calorimetry, heat andpressure output measurements. Different compositions were prepared by varying the amount ofRDX/HMX from 10 per cent to 50 per cent. Thermal studies on the B-KNO3/high explosivemixtures reveal that these undergo two-stage decomposition. The first stage corresponds to thedecomposition of high explosive and the second stage corresponds to that of the reaction betweenB and KNO3. Kinetic parameters were calculated for both the stages of TG curves using Coats-Redfern and Mac Callum-Tanner methods. Ignition temperature of B-KNO3 decreases on theaddition of RDX/HMX while the onset of RDX or HMX decomposition is not significantly affectedby B-KNO3. The pressure output of B-KNO3 increases on adding RDX/HMX. The heat outputof B-KNO3 is not much affected by the addition of RDX or HMX, even though the heat ofexplosion of RDX and HMX are low. This is due to the reaction between the combustion productsof RDX/HMX and reaction products of B-KNO3 to form more exothermic products like B2O3,releasing extra heat. The flame temperature of the charge increases while the average molecularweight of the products of combustion decreases as the RDX/HMX content increases. Thus, thecharge, on addition of RDX or HMX, produces higher pressure output, maintaining the heatoutput at comparable levels.

  3. Theoretical studies on the thermodynamic properties and detonation properties of cyclotrimethylene trinitramine (RDX with aluminum and boron metals.

    Nilgün Şen


    Full Text Available The B3LYP/6-311++G(2df,2p density functional theory (DFT method was used to investigate molecular geometry and thermodynamic properties of RDX and RDX derivatives containing Al and B metals. The detonation velocity (D and detonation pressure (P, estimated by using Kamlet–Jacobs and in literature equations, respectively. Total energies (Et, frontier orbital energy (EHOMO, ELOMO, energy gap (ΔELUMO–HOMO and theoretical molecular density (ρ were calculated with Spartan 14 software package program. It was shown that the presence of aluminum and boron atoms affects the good thermal stabilities. The results show that the composite RDX-Al, RDX-B derivatives have higher detonation performance and higher density than RDX. RDX-Al derivatives appeared to be superior to RDX-B mixtures in terms of these parameters. These results provide information on the moleculer design of new energetic materials.

  4. Biostimulation and microbial community profiling reveal insights on RDX transformation in groundwater.

    Wang, Dongping; Boukhalfa, Hakim; Marina, Oana; Ware, Doug S; Goering, Tim J; Sun, Fengjie; Daligault, Hajnalka E; Lo, Chien-Chi; Vuyisich, Momchilo; Starkenburg, Shawn R


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a high explosive released to the environment as a result of weapons manufacturing and testing worldwide. At Los Alamos National Laboratory, the Technical Area (TA) 16 260 Outfall discharged high-explosives-bearing water from a high-explosives-machining facility to Cañon de Valle during 1951 through 1996. These discharges served as a primary source of high-explosives and inorganic-element contamination in the area. Data indicate that springs, surface water, alluvial groundwater, and perched-intermediate groundwater contain explosive compounds, including RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine); HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine); and TNT (2,4,6-trinitrotoluene). RDX has been detected in the regional aquifer in several wells, and a corrective measures evaluation is planned to identify remedial alternatives to protect the regional aquifer. Perched-intermediate groundwater at Technical Area 16 is present at depths from 650 ft to 1200 ft bgs. In this study, we examined the microbial diversity in a monitoring well completed in perched-intermediate groundwater contaminated by RDX, and examined the response of the microbial population to biostimulation under varying geochemical conditions. Results show that the groundwater microbiome was dominated by Actinobacteria and Proteobacteria. A total of 1,605 operational taxonomic units (OTUs) in 96 bacterial genera were identified. Rhodococcus was the most abundant genus (30.6%) and a total of 46 OTUs were annotated as Rhodococcus. One OTU comprising 25.2% of total sequences was closely related to a RDX -degrading strain R. erythropolis HS4. A less abundant OTU from the Pseudomonas family closely related to RDX-degrading strain P. putida II-B was also present. Biostimulation significantly enriched Proteobacteria but decreased/eliminated the population of Actinobacteria. Consistent with RDX degradation, the OTU closely related to the RDX-degrading P

  5. Modeling the anisotropic shock response of single-crystal RDX

    Luscher, Darby

    Explosives initiate under impacts whose energy, if distributed homogeneously throughout the material, translates to temperature increases that are insufficient to drive the rapid chemistry observed. Heterogeneous thermomechanical interactions at the meso-scale (i.e. between single-crystal and macroscale) leads to the formation of localized hot spots. Direct numerical simulations of mesoscale response can contribute to our understanding of hot spots if they include the relevant deformation mechanisms that are essential to the nonlinear thermomechanical response of explosive molecular crystals. We have developed a single-crystal model for the finite deformation thermomechanical response of cyclotrimethylene trinitramine (RDX). Because of the low symmetry of RDX, a complete description of nonlinear thermoelasticity requires a careful decomposition of free energy into components that represent the pressure-volume-temperature (PVT) response and the coupling between isochoric deformation and both deviatoric and hydrostatic stresses. An equation-of-state (EOS) based on Debye theory that defines the PVT response was constructed using experimental data and density functional theory calculations. This EOS replicates the equilibrium states of phase transformation from alpha to gamma polymorphs observed in static high-pressure experiments. Lattice thermoelastic parameters defining the coupled isochoric free energy were obtained from molecular dynamics calculations and previous experimental data. Anisotropic crystal plasticity is modeled using Orowan's expression relating slip rate to dislocation density and velocity. Details of the theory will be presented followed by discussion of simulations of flyer plate impact experiments, including recent experiments diagnosed with in situ X-ray diffraction at the Advanced Photon Source. Impact conditions explored within the experimental effort have spanned shock pressures ranging from 1-10 GPa for several crystallographic orientations

  6. CTMAB改性膨润土处理黑索今废水的研究%Research on the Treatment of RDX Wastewater with Bentonite modified by CTMAB

    边阔; 周勇; 戴秋洪; 卫双果


    In this paper, the bentonite modified by CTMAB was employed to dispose RDX wastewater. The efficiency was affected by factors such as the dosage of bentonite modified by CTMAB, the pH value, the oscillation frequency, the oscillation time and the activation temperature. The test results showed that the bentonite modified by CTMAB could effectively dispose the RDX wastewater. Under the condition of that the oscillation frequency was 120 r/min, the concentration of RDX was 120 mg/L, the dosage of bentonite modified by CTMAB was 1.2 g, the pH value was 7, the activation temperature was 60 ℃ and the oscillation time was 80 min. The removal efficiency of RDX reached 94.8% and the removal efficiency of CODCr come up to 82.5%.%为了处理黑索今(RDX)废水,研究了十六烷基三甲基溴化铵(CTMAB)改性膨润土的用量、pH值、振荡频率、振荡时间、活化温度对C1、MAB改性膨润土处理RDX废水效果的影响。CTMAB改性膨润土对RDX废水有较好的处理效果,在振荡频率为100r/min下,RDX废水初始浓度120mg/L、CTMAB改性膨润土的用量为1.2g、pH为7、活化温度60℃、振荡时间80min时,RDX去除率达到94.8%,CODCr去除率为82.5%。

  7. DDT Behavior of Waxed Mixtures of RDX, HMX, and Tetryl


    NSWC/WOL TR 77-96 O DDT BEHAVIOR OF WAXED MIXTURES OF " RDX, HMX, AND TETRYL BY DONNA PRICE and RICHARD R. BERNECKER RESEARCH AND TECHNOLOGY...50.95 mm OD) with heavy end closures was used. A B/ KNO3 ignitor (1) was used to ignite one end of the 295.4 mm explosive column. Charge loading, reduction are also as in reference 1 with the modification for strain gages given in reference 2. I. R. R. Bernecker and D. Price , "Transition

  8. The Dynamic Behaviors of Single Crystal RDX Under Ramp Wave Loading to 15GPa

    Wang, Guiji; Cai, Jintao; Zhao, Jianheng; Zhao, Feng; Wu, Gang; Tan, Fuli; Sun, Chengwei

    Based on high pulsed power generator CQ-4, the single crystal RDX explosive was researched along different crystal orientations under ramp wave loadings up to 15 GPa. The typical three-wave structures were obtained by means of laser interferometry PDV, which show the elastic-plastic transition and α to γ phase transition. The ramp elastic limit (REL) and yield strength of RDX along 210 and 100 crystal orientations were respectively calculated and the resuts show obvious effects of crystal orientaions for RDX. The ramp elastic limit σIEL of RDX along 210 orientation is 0.688-0.758GPa, and the σIEL of RDX along 100 is 1.039 -1.110 GPa. The α to γ phase transformation characteristics were also analyzed based on the experimental data. The initial phase transition pressure for the two crystal orientation of RDX are about 3.5 to 4 GPa, which agree well with the data of about 4-5GPa given by MD simulation. The data directly validate the results given by Raman Spectrum under shock compression and static high pressure, which couldn't be observed by wave profiles. The experimental data can be used to verify and validate the new models of RDX under dynamic loading. Supported by NSFC of China under Contract No.11327803 and 11176002

  9. Frictional properties of single crystals HMX, RDX and PETN explosives.

    Wu, Y Q; Huang, F L


    The frictional properties of single crystals of cyclotetramethylene tetranitramine (HMX), cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN) secondary explosives are examined using a sensitive friction machine. The explosive crystals used for the measurements are at least 3.5 mm wide. The friction coefficients between crystals of the same explosive (i.e., HMX on HMX, etc.), crystals of different explosives (i.e., HMX on RDX, etc.), and each explosive and a well-polished gauge steel surface are determined. The frictional surfaces are also studied under an environmental scanning electron microscope (ESEM) to analyze surface microstructural changes under increasing loading forces. The friction coefficients vary considerably with increasing normal loading forces and are particularly sensitive to slider shapes, crystal roughness and the mechanical properties of both the slider and the sample. With increasing loading forces, most friction experiments show surface damage, consisting of grooves, debris, and nano-particles, on both the slider and sample. In some cases, a strong evidence of a localized molten state is found in the central region of the friction track. Possible mechanisms that affect the friction coefficient are discussed based on microscopic observations. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Particle characteristics of trace high explosives: RDX and PETN.

    Verkouteren, Jennifer R


    The sizes of explosives particles in fingerprint residues produced from C-4 and Semtex-1A were investigated with respect to a fragmentation model. Particles produced by crushing crystals of RDX and PETN were sized by using scanning electron microscopy, combined with image analysis, and polarized light microscopy was used for imaging and identifying explosive particles in fingerprint residues. Crystals of RDX and PETN fragment in a manner that concentrates mass in the largest particles of the population, which is common for a fragmentation process. Based on the fingerprints studied, the particle size to target for improving mass detection in fingerprint residues by ion mobility spectrometry (IMS) is > or = 10 microm in diameter. Although particles smaller than 10 microm in diameter have a higher frequency, they constitute < 20% of the total mass. Efforts to improve collection efficiency of explosives particles for detection by IMS, or other techniques, must take into consideration that the mass may be concentrated in a relatively few particles that may not be homogeneously distributed over the fingerprint area. These results are based on plastic-bonded explosives such as C-4 that contain relatively large crystals of explosive, where fragmentation is the main process leading to the presence of particles in the fingerprint residues.

  11. Critical analysis of nitramine decomposition data: Activation energies and frequency factors for HMX and RDX decomposition

    Schroeder, M. A.


    A summary of a literature review on thermal decomposition of HMX and RDX is presented. The decomposition apparently fits first order kinetics. Recommended values for Arrhenius parameters for HMX and RDX decomposition in the gaseous and liquid phases and for decomposition of RDX in solution in TNT are given. The apparent importance of autocatalysis is pointed out, as are some possible complications that may be encountered in interpreting extending or extrapolating kinetic data for these compounds from measurements carried out below their melting points to the higher temperatures and pressure characteristic of combustion.

  12. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong


    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation in aquifer sediments under manganese-reducing conditions

    Bradley, Paul M.; Dinicola, Richard S.


    A shallow, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)–contaminated aquifer at Naval Submarine Base Bangor has been characterized as predominantly manganese-reducing, anoxic with local pockets of oxic conditions. The potential contribution of microbial RDX degradation to localized decreases observed in aquifer RDX concentrations was assessed in sediment microcosms amended with [U-14C] RDX. Greater than 85% mineralization of 14C-RDX to 14CO2 was observed in aquifer sediment microcosms under native, manganese-reducing, anoxic conditions. Significant increases in the mineralization of 14C-RDX to 14CO2 were observed in anoxic microcosms under NO3-amended or Mn(IV)-amended conditions. No evidence of 14C-RDX biodegradation was observed under oxic conditions. These results indicate that microbial degradation of RDX may contribute to natural attenuation of RDX in manganese-reducing aquifer systems.

  14. Effects of Hexachlorocyclotriphosphazene on Performance of RDX-CMDB Propellant%六氯环三磷腈对RDX-CMDB推进剂性能的影响

    刘所恩; 张国辉; 王月丽; 刘玉存; 王建中; 吴瑞强; 任晓斌


    In order to investigate the effects of hexachlorocyclotriphosphazene (HCCT) as reducing rate agent on the burning rate, chemical stability, heat of detonation, mechanical sensitivity and mechanical properties of RDX-CMDB propellant, the compatibility of HCCT with the main components of RDX-CMDB propellant was tested and the performances of three kinds of RDX-CMDB propellants with different contents of HCCT were measured by target line method, methyl violet test, adiabatic method, etc. The results show that HCCT has good compatibility with the main components NC+NG and RDX of RDX-CMDB propellant, the addition of HCCT makes the burning rate of the propellant at the pressure of 2-6MPa decrease and the burning rate pressure exponent increase, the heat of detonation, fraction sensitivity and impact sensitivity all decrease, the tensile strength and elongation rate remain basically unchanged,and it has no effect on the chemical stability of the propellant.%为考察六氯环三磷腈(HCCT)作为降速剂对RDX-CMDB推进剂燃速、安定性、爆热、机械感度、力学性能的影响,测试了HCCT与RDX-CMDB主要组分的相容性,并采用靶线法、甲基紫法、绝热法等测试了3种不同HCCT含量的RDX-CMDB推进剂的性能.结果表明, HCCT与RDX-CMDB推进剂主要组分NC+NG及RDX的相容性较好,HCCT的加入使推进剂在2~6MPa压强下燃速降低,燃速压强指数升高,爆热降低,摩擦感度和撞击感度降低,抗拉强度及延伸率基本不变,对推进剂的化学安定性没有影响.

  15. Slow release of PCB, TNT, and RDX from soils and sediments: final report

    Brannon, James M


    .... This phenomenon gratly complicates the prediction of leaching and microbial degradation rates. This study explored the adsroption/desorption of PBC, TNT, and RDX onto activated carbona dn soils over time and the implications for contaminant mobility...

  16. Characterization of defects and role of molecular flexibility in cyclotrimethyelenetrinitramine (RDX)

    Pal, Anirban

    Molecular crystals typically comprise irregularly shaped molecules packed in low symmetry crystalline configurations. The anisotropic nature of bonding and low cohesive energies are responsible for their complex and novel mechanical, electronic, vibrational, and optical properties. Owing to their importance in pharmaceutical, electronic, energetic and food materials, this class of crystals has fostered myriad investigations over the last century. This dissertation focuses on a specific molecular crystal, alpha-cyclotrimethylene trinitramine (alpha-RDX), which is a commonly used energetic material. There are three investigation tracks in this work. First, a type of point defect that is specific to molecular crystals, called orientational defect , is presented and studied for alpha-RDX. Secondly, since this molecular crystal comprises flexible molecules, the influence of such flexibility on elastic-plastic properties of alpha-RDX is quantified. Thirdly, the Peierls free energy barriers for the motion of dislocations in alpha-RDX is estimated using a novel umbrella sampling based technique.

  17. RDX binds to the GABA(A) receptor-convulsant site and blocks GABA(A) receptor-mediated currents in the amygdala: a mechanism for RDX-induced seizures.

    Williams, Larry R; Aroniadou-Anderjaska, Vassiliki; Qashu, Felicia; Finne, Huckelberry; Pidoplichko, Volodymyr; Bannon, Desmond I; Braga, Maria F M


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a high-energy, trinitrated cyclic compound that has been used worldwide since World War II as an explosive in both military and civilian applications. RDX can be released in the environment by way of waste streams generated during the manufacture, use, and disposal of RDX-containing munitions and can leach into groundwater from unexploded munitions found on training ranges. For > 60 years, it has been known that exposure to high doses of RDX causes generalized seizures, but the mechanism has remained unknown. We investigated the mechanism by which RDX induces seizures. By screening the affinity of RDX for a number of neurotransmitter receptors, we found that RDX binds exclusively to the picrotoxin convulsant site of the γ-aminobutyric acid type A (GABA(A)) ionophore. Whole-cell in vitro recordings in the rat basolateral amygdala (BLA) showed that RDX reduces the frequency and amplitude of spontaneous GABA(A) receptor-mediated inhibitory postsynaptic currents and the amplitude of GABA-evoked postsynaptic currents. In extracellular field recordings from the BLA, RDX induced prolonged, seizure-like neuronal discharges. These results suggest that binding to the GABA(A) receptor convulsant site is the primary mechanism of seizure induction by RDX and that reduction of GABAergic inhibitory transmission in the amygdala is involved in the generation of RDX-induced seizures. Knowledge of the molecular site and the mechanism of RDX action with respect to seizure induction can guide therapeutic strategies, allow more accurate development of safe thresholds for exposures, and help prevent the development of new explosives or other munitions that could pose similar health risks.

  18. Plastic explosive RDX: Cyclotrimethylenetrinitramine. (Latest citations from the NTIS bibliographic database). Published Search



    The bibliography contains citations concerning the properties and handling of plastics explosive RDX. Production, decomposition, toxicology studies, and desensitizing techniques are discussed. RDX detection in munitions plant wastewater and air samples is described along with methods of eliminating this explosive from the effluent. Molecular dynamics, sensitivity to shock and heat, burning behavior, and explosion velocity are presented. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. Cost and Performance Report: Bioaugmentation for Aerobic Bioremediation of RDX-Contaminated Groundwater


    water standards (Maximum Contaminant Level) for RDX; however, the U.S. Environmental Protection Agency (USEPA) has listed RDX on the Drinking Water ...diazabutanal O&M Operation and maintenance O2 dissolved oxygen OD Optical density ORP Oxidation reduction potential OSU Oregon State University P&T...anaerobic biostimulation, and aerobic biostimulation without bioaugmentation. 2 1.3 REGULATORY DRIVERS There are currently no Federal drinking

  20. Role of Myelofibrosis in Hematotoxicity of Munition RDX Environmental Degradation Product MNX


    marrow toxicity including fibrosis. In addition, effects of parent RDX on selected endpoints will be assessed to provide structure -activity information...Fig. 2). Peripheral granulocytes are comprised of neutrophils, basophils , eosinophils and monocytes. Although the CELL-DYNE blood analyzer...colleagues (MacMillan, Denise, et al.) on disposition and metabolism of RDX and MNX is currently undergoing internal review and will be submitted for

  1. RDX-Polyethylene Wax Formulations as Potential Replacements for Tetryl in Fuze Leads, Boosters and Magazines


    prepared by the solvent cut method, PBX-9407, are listed for comparison with RDX and Tetryl in Table 2. The substantial decrease in impact sensitivity...earliest MRL studies dealt with RDX grade ~ 1 1 % polyethylene wax as a potential replacement for beeswax in Comp. B RD~/~~~/ beeswax 60:40:1 [6,71. Some... solvent or toxic vapours, and all major ingredients are of low toxicity. The polyethylene wax is readily available through local suppliers and the

  2. Quasi-static response and texture evolution of α- and γ-RDX: a comparative study

    Josyula, Kartik; Rahul; De, Suvranu


    In this paper, we undertake a comparative study of the stress-strain response and slip activity of α- and γ-polymorph of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under pressure loading using a rate-dependent single-crystal plasticity model. Texture evolution studies are performed to further understand the effects of the dominant slip systems. The simulations indicate that the difference in elastic moduli and lattice parameters for α- and γ-RDX lead to different elastic-plastic constitutive response in the two polymorphs. γ-RDX exhibits more plastic slip compared to α-RDX for loading on (1 1 1) plane and the two polymorphs have different sets of dominant slip systems. We observe that the high-pressure slip system (0 0 1)[0 1 0] that is determined using molecular dynamics simulations is the most dominant slip system for this orientation. Whereas, for loading on (2 1 0) plane, α-RDX has marginally higher plastic slip than γ-RDX, though the same slip system is dominant for both the polymorphs. The texture evolution for loading on (1 1 1) and (2 1 0) planes follow the path towards the most dominant slip systems for both the polymorphs. We predict that the larger plastic slip in γ-RDX for loading on (1 1 1) plane might play an important role in understanding the reduced sensitivity for shock loading on (1 1 1) plane, when compared to (2 1 0) for which γ-RDX has lesser plastic slip, and (1 0 0) which is purely elastic.

  3. Transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by permanganate.

    Chokejaroenrat, Chanat; Comfort, Steve D; Harris, Clifford E; Snow, Daniel D; Cassada, David; Sakulthaew, Chainarong; Satapanajaru, Tunlawit


    The chemical oxidant permanganate (MnO(4)(-)) has been shown to effectively transform hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) at both the laboratory and field scales. We treated RDX with MnO(4)(-) with the objective of quantifying the effects of pH and temperature on destruction kinetics and determining reaction rates. A nitrogen mass balance and the distribution of reaction products were used to provide insight into reaction mechanisms. Kinetic experiments (at pH ∼ 7, 25 °C) verified that RDX-MnO(4)(-) reaction was first-order with respect to MnO(4)(-) and initial RDX concentration (second-order rate: 4.2 × 10(-5) M(-1) s(-1)). Batch experiments showed that choice of quenching agents (MnSO(4), MnCO(3), and H(2)O(2)) influenced sample pH and product distribution. When MnCO(3) was used as a quenching agent, the pH of the RDX-MnO(4)(-) solution was relatively unchanged and N(2)O and NO(3)(-) constituted 94% of the N-containing products after 80% of the RDX was transformed. On the basis of the preponderance of N(2)O produced under neutral pH (molar ratio N(2)O/NO(3) ∼ 5:1), no strong pH effect on RDX-MnO(4)(-) reaction rates, a lower activation energy than the hydrolysis pathway, and previous literature on MnO(4)(-) oxidation of amines, we propose that RDX-MnO(4)(-) reaction involves direct oxidation of the methylene group (hydride abstraction), followed by hydrolysis of the resulting imides, and decarboxylation of the resulting carboxylic acids to form N(2)O, CO(2), and H(2)O.

  4. Effects of Copper Salts on Combustion Characteristics of RDX-CMDB Propellant%铜盐对RDX-CMDB推进剂燃烧性能的影响

    范军管; 付小龙; 蔚红建; 张晓宏; 樊学忠


    研究了6种铜盐(DBC、CNI、NT-Cu、B-Cu、S-Cu、A-Cu)以及铜盐/炭黑复配体系对RDX-CMDB推进剂燃烧性能的影响,用扫描电镜和元素分析测试了推进剂的熄火表面.结果表明,铜盐可降低RDX-CMDB推进剂在16~22 MPa的压强指数;在10~22 MPa,铜盐和铜/炭黑混合物对RDX-CMDB推进剂燃烧特性的影响不显著.铜盐催化剂以及铜盐和炭黑复配催化剂对推进剂的燃烧反应有一定的促进作用.

  5. Experimental investigation into the detonation characteristics of hybrid RDX-ethylene-air mixtures

    Yang, L.; Yao, J.; Yang, Z.; Xie, L.; Peng, J.; Rao, G.


    An experimental study is conducted to determine the detonation characteristics of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) particles dispersed in a gaseous fuel air mixture in a vertical detonation tube with an inner diameter of 200 mm and a height of 5400 mm. Experiments are performed in both ethylene-air mixtures and RDX-ethylene-air hybrid mixtures. The detonation front pressure and velocity are measured with six pressure transducers along the detonation tube. The results show that the addition of RDX assists 4.0 vol.% ethylene-air mixtures in achieving detonation. The detonation front pressure increases noticeably with dust concentration up to 474 g/m3 in the RDX-ethylene-air hybrid mixtures, but the velocity only increases slightly. The cellular structures of RDX-ethylene-air hybrid mixtures and ethylene-air mixtures were obtained with the use of smoked foils and exhibit irregular structures. It is found that the measured cell size has a U-shaped curve with respect to RDX concentration.

  6. Optimizing detection of RDX vapors using designed experiments for remote sensing

    Ewing, Robert G.; Heredia-Langner, Alejandro; Warner, Marvin G.


    Abstract: This paper presents results of experiments performed to study the effect of four factors on the detection of RDX vapors from desorption into an atmospheric flow tube mass spectrometer (AFT-MS). The experiments initially included four independent factors: gas flow rate, desorption current, solvent evaporation time and RDX mass. The values of three detection responses, peak height, peak width, and peak area were recorded but only the peak height response was analyzed. Results from the first block of experiments indicated that solvent evaporation time was not statistically significant. A second round of experiments was performed using flow rate, current, and RDX mass as factors and the results were used to create a model to predict conditions resulting in maximum peak height. Those conditions were confirmed experimentally and used to obtain data for a calibration model. The calibration model represented RDX amounts ranging from 1 to 25 pg desorbed into an air flow of 7 L/min. Air samples from a shipping container that held 2 closed explosive storage magazines were collected on metal filaments for varying amounts for time ranging from 5 to 90 minutes. RDX was detected from all of the filaments sampled by desorption into the AFT-MS. From the calibration model, RDX vapor concentrations within the shipping container were calculated to be in the range of 1 to 50 parts-per-quadrillion from data collected on 2 separate days.

  7. Anaerobic treatment of army ammunition production wastewater containing perchlorate and RDX.

    Atikovic, Emina; Suidan, Makram T; Maloney, Stephen W


    Perchlorate is an oxidizer that has been routinely used in solid rocket motors by the Department of Defense and National Aeronautics and Space Administration. Royal Demolition Explosive (RDX) is a major component of military high explosives and is used in a wide variety of munitions. Perchlorate bearing wastewater typically results from production of solid rocket motors, while RDX is transferred to Army industrial wastewaters during load, assemble and pack operations for new munitions, and hot water or steam washout for disposal and deactivation of old munitions (commonly referred to as demilitarization, or simply demil). Biological degradation in Anaerobic Fluidized Bed Reactors (AFBR), has been shown to be an effective method for the removal of both perchlorate and RDX in contaminated wastewater. The focus of this study was to determine the effectiveness of removal of perchlorate and RDX, individually and when co-mingled, using ethanol as an electron donor under steady state conditions. Three AFBRs were used to assess the effectiveness of this process in treating the wastewater. The performance of the bioreactors was monitored relative to perchlorate, RDX, and chemical oxygen demand removal effectiveness. The experimental results demonstrated that the biodegradation of perchlorate and RDX was more effective in bioreactors receiving the single contaminant than in the bioreactor where both contaminants were fed.

  8. Stable isotope probing reveals the importance of Comamonas and Pseudomonadaceae in RDX degradation in samples from a Navy detonation site.

    Jayamani, Indumathy; Cupples, Alison M


    This study investigated the microorganisms involved in hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation from a detonation area at a Navy base. Using Illumina sequencing, microbial communities were compared between the initial sample, samples following RDX degradation, and controls not amended with RDX to determine which phylotypes increased in abundance following RDX degradation. The effect of glucose on these communities was also examined. In addition, stable isotope probing (SIP) using labeled ((13)C3, (15)N3-ring) RDX was performed. Illumina sequencing revealed that several phylotypes were more abundant following RDX degradation compared to the initial soil and the no-RDX controls. For the glucose-amended samples, this trend was strong for an unclassified Pseudomonadaceae phylotype and for Comamonas. Without glucose, Acinetobacter exhibited the greatest increase following RDX degradation compared to the initial soil and no-RDX controls. Rhodococcus, a known RDX degrader, also increased in abundance following RDX degradation. For the SIP study, unclassified Pseudomonadaceae was the most abundant phylotype in the heavy fractions in both the presence and absence of glucose. In the glucose-amended heavy fractions, the 16S ribosomal RNA (rRNA) genes of Comamonas and Anaeromxyobacter were also present. Without glucose, the heavy fractions also contained the 16S rRNA genes of Azohydromonas and Rhodococcus. However, all four phylotypes were present at a much lower level compared to unclassified Pseudomonadaceae. Overall, these data indicate that unclassified Pseudomonadaceae was primarily responsible for label uptake in both treatments. This study indicates, for the first time, the importance of Comamonas for RDX removal.

  9. 镍粉对RDX-CMDB推进剂燃烧性能的影响%Effects of Nickel Powder on the Combustion Performance of RDX- CMDB Propellant

    马亮; 陈俊波; 郑伟; 张超


    The influences of particle size and content of nickel powder on combustion performance of RDX-CMDB propellant were investigated. The results showed that nickel powder could improve the burning rate of RDX -CMDB propellant significantly. The burning rate was the highest when adding the amount of 1.5% nickel powder with3μmunder 1~10MPa. The combustion flame areas increased greatly when adding nickel powder, meanwhile, the thickness of dark area was decreased. The combustion wave temperature distribution were studied under 1MPa, the results revealed that combustion surface temperatureTs did not change obviously, however the adiabatic flame temperature increased substantially as adding nickel powder.%研究了不同粒径(1μm、3μm、5μm)与含量的镍粉对RDX-CMDB推进剂燃烧性能的影响。燃速测试结果表明:镍粉能有效提高RDX-CMDB推进剂的燃速。1~10MPa下,添加1.5%的3μm镍粉的RDX-CMDB推进剂燃速最高。火焰结构照片显示RDX-CMDB推进剂体系中加入镍粉,燃烧火焰面积大大增加,且降低了暗区厚度。1MPa下的燃烧波温度分布曲线结果显示镍粉的加入对推进剂的燃面温度无较大影响,但是绝热火焰温度大幅度地提高。

  10. RDX 基含硼炸药的能量特性%Energy Characteristics of RDX-based Boron-contained Explosive

    黄亚峰; 王晓峰; 赵东奎


    To investigate the energy characteristics of RDX-based boron-contained explosive,the heat of detonation and work capacity of the RDX-based explosive with various boron content were measured by means of the specification of standardization methods GJB772A-97-701.1 and GJB772A-97-705.1,respectively.The underwater energy of the RDX-based explosive was calculated through the relation curves of overpressure and time measured by the sensor.The results show that the heat of detonation,underwater energy and work capacity of the explosive can be improved by adding boron powder into RDX.When the mass fraction of boron content is 20%,the heat of detonation reaches the maximum value of 7 162 kJ/kg.When the mass fraction of boron content is lower than 20%, the underwater total energy is of linear correlation with boron content.When the mass fraction of boron content is 10%,the work capacity reaches the maximum,which is 1.649 times of TNT equivalence.%为了研究 RDX 基含硼炸药的能量特性,按照 GJB772A-1997701.1方法和705.1方法分别测试了不同硼含量的 RDX 基含硼炸药的爆热和作功能力,通过传感器测得 RDX 基含硼炸药超压和时间的关系曲线,并计算了水下能量。结果表明,在 RDX 中添加硼粉可以提高炸药的爆热、水下能量和作功能力。当硼的质量分数为20%时,爆热达到最大值7162 kJ/kg;当硼的质量分数低于20%时,水下总能量与硼含量呈线性相关。当硼的质量分数为10%时,作功能力达到最大,为1.649倍 TNT 当量。

  11. Interspecific effects of 4A-DNT (4-amino-2,6-dinitrotoluene) and RDX (1,3,5-trinitro-1,3,5-triazine) in Japanese quail, Northern bobwhite, and Zebra finch.

    Quinn, Michael J; Hanna, Terry L; Shiflett, Alicia A; McFarland, Craig A; Cook, Michelle E; Johnson, Mark S; Gust, Kurt A; Perkins, Edward J


    The purpose of this study was to assess the toxicological effects of two munition compounds, 4-amino-2,6-dinitrotoluene (4A-DNT) and 1,3,5-trinitro-1,3,5-triazine (RDX), on three different bird species: two common toxicological model species-the Northern Bobwhite (Colinus virginianus) and the Japanese Quail (Coturnix japonica), and a representative passerine-the Zebra Finch (Taeniopygia guttata). Bobwhite were exposed to 4A-DNT at 0, 8, 15, 30, 60, or 150 mg/kg body weight (bw) d by oral gavage for seven days; because the high dose of 4A-DNT was lethal to bobwhite, the maximum dose was changed to 100 mg/kg bw d for Japanese quail and finches to ensure tissue could be used for future toxicogenomic work. RDX was similarly administered at 0, 0.5, 1.5, 3, 6, or 12 mg/kg bw d. Blood was drawn prior to euthanasia for blood cellularity and chemistry analyses. Finches were clearly least affected by 4A-DNT as evidenced by a lack of observable effects. Bobwhite appeared to be the most sensitive species to 4A-DNT as observed through changes in blood cellularity and plasma chemistry effects. Bobwhite appeared to be more sensitive to RDX than Japanese Quail due to increased effects on measures of plasma chemistries. Finches exhibited the greatest sensitivity to RDX through increased mortality and seizure activity. This study suggests that sensitivity among species is chemical-specific and provides data that could be used to refine current avian sensitivity models used in ecological risk assessments.

  12. Anaerobic bioremediation of RDX by ovine whole rumen fluid and pure culture isolates.

    Eaton, H L; Duringer, J M; Murty, L D; Craig, A M


    The ability of ruminal microbes to degrade the explosive compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in ovine whole rumen fluid (WRF) and as 24 bacterial isolates was examined under anaerobic conditions. Compound degradation was monitored by high-performance liquid chromatography analysis, followed by liquid chromatography-tandem mass spectrometry identification of metabolites. Organisms in WRF microcosms degraded 180 μM RDX within 4 h. Nitroso-intermediates hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) were present as early as 0.25 h and were detected throughout the 24-h incubation period, representing one reductive pathway of ring cleavage. Following reduction to MNX, peaks consistent with m/z 193 and 174 were also produced, which were unstable and resulted in rapid ring cleavage to a common metabolite consistent with an m/z of 149. These represent two additional reductive pathways for RDX degradation in ovine WRF, which have not been previously reported. The 24 ruminal isolates degraded RDX with varying efficiencies (0-96 %) over 120 h. Of the most efficient degraders identified, Clostridium polysaccharolyticum and Desulfovibrio desulfuricans subsp. desulfuricans degraded RDX when medium was supplemented with both nitrogen and carbon, while Anaerovibrio lipolyticus, Prevotella ruminicola, and Streptococcus bovis IFO utilized RDX as a sole source of nitrogen. This study showed that organisms in whole rumen fluid, as well as several ruminal isolates, have the ability to degrade RDX in vitro and, for the first time, delineated the metabolic pathway for its biodegradation.

  13. Biodegradation of RDX nitroso products MNX and TNX by cytochrome P450 XplA.

    Halasz, Annamaria; Manno, Dominic; Perreault, Nancy N; Sabbadin, Federico; Bruce, Neil C; Hawari, Jalal


    Anaerobic transformation of the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) by microorganisms involves sequential reduction of N-NO(2) to the corresponding N-NO groups resulting in the initial formation of MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine). MNX is further reduced to the dinitroso (DNX) and trinitroso (TNX) derivatives. In this paper, we describe the degradation of MNX and TNX by the unusual cytochrome P450 XplA that mediates metabolism of RDX in Rhodococcus rhodochrous strain 11Y. XplA is known to degrade RDX under aerobic and anaerobic conditions, and, in the present study, was found able to degrade MNX to give similar products distribution including NO(2)(-), NO(3)(-), N(2)O, and HCHO but with varying stoichiometric ratio, that is, 2.06, 0.33, 0.33, 1.18, and 1.52, 0.15, 1.04, 2.06, respectively. In addition, the ring cleavage product 4-nitro-2,4,-diazabutanal (NDAB) and a trace amount of another intermediate with a [M-H](-) at 102 Da, identified as ONNHCH(2)NHCHO (NO-NDAB), were detected mostly under aerobic conditions. Interestingly, degradation of TNX was observed only under anaerobic conditions in the presence of RDX and/or MNX. When we incubated RDX and its nitroso derivatives with XplA, we found that successive replacement of N-NO(2) by N-NO slowed the removal rate of the chemicals with degradation rates in the order RDX > MNX > DNX, suggesting that denitration was mainly responsible for initiating cyclic nitroamines degradation by XplA. This study revealed that XplA preferentially cleaved the N-NO(2) over the N-NO linkages, but could nevertheless degrade all three nitroso derivatives, demonstrating the potential for complete RDX removal in explosives-contaminated sites.

  14. Horizontal gene transfer (HGT) as a mechanism of disseminating RDX-degrading activity among Actinomycete bacteria.

    Jung, C M; Crocker, F H; Eberly, J O; Indest, K J


    Hexahydro-1,3,5-trinitro-1,3,5,-triazine (RDX) is a cyclic nitramine explosive that is a major component in many high-explosive formulations and has been found as a contaminant of soil and groundwater. The RDX-degrading gene locus xplAB, located on pGKT2 in Gordonia sp. KTR9, is highly conserved among isolates from disparate geographical locations suggesting a horizontal gene transfer (HGT) event. It was our goal to determine whether Gordonia sp. KTR9 is capable of transferring pGKT2 and the associated RDX degradation ability to other bacteria. We demonstrate the successful conjugal transfer of pGKT2 from Gordonia sp. KTR9 to Gordonia polyisoprenivorans, Rhodococcus jostii RHA1 and Nocardia sp. TW2. Through growth and RDX degradation studies, it was demonstrated that pGKT2 conferred to transconjugants the ability to degrade and utilize RDX as a nitrogen source. The inhibitory effect of exogenous inorganic nitrogen sources on RDX degradation in transconjugant strains was found to be strain specific. Plasmid pGKT2 can be transferred by conjugation, along with the ability to degrade RDX, to related bacteria, providing evidence of at least one mechanism for the dissemination and persistence of xplAB in the environment. These results provide evidence of one mechanism for the environmental dissemination of xplAB and provide a framework for future field relevant bioremediation practices. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology. No claim to US Government works.

  15. Resonance Raman spectra of TNT and RDX using vibronic theory, excited-state gradient, and complex polarizability approximations.

    Al-Saidi, W A; Asher, Sanford A; Norman, Patrick


    Geometries, UV absorption bands, and resonance Raman (RR) cross sections of TNT and RDX are investigated using density functional theory (DFT) in conjunction with the Coulomb attenuated B3LYP exchange-correlation functional. The absorption and RR spectra are determined with use of vibronic (VB) theory, excited-state gradient, and complex polarizability (CPP) approximations. We examined low-energy isomers (two for TNT and four for RDX) whose energies differ by less than 1 kcal/mol, such that they would appreciably be populated at room temperature. The two TNT isomers differ by an internal rotation of the methyl group, while the four conformers of RDX differ by the arrangements of the nitro group relative to the ring. Our theoretical optical properties of the TNT and RDX isomers are in excellent agreement with experimental and recent CCSD-EOM results, respectively. For the two TNT isomers, the ultraviolet RR (UVRR) spectra are similar and in good agreement with recently measured experimental results. Additionally, the UVRR spectra computed using the excited-state and CPP approaches compare favorably with the VB theory results. On the other hand, the RR spectra of the RDX conformers differ from one another, reflecting the importance of the positioning of the NO2 groups with respect to the ring. In the gas phase or in solution, RDX would give a spectrum associated with a conformationally averaged structure. It is encouraging that the computed spectra of the conformers show similarities to recent measured RDX spectra in acetonitrile solution, and reproduce the 10-fold decrease in the absolute Raman cross sections of RDX compared to TNT for the observed 229 nm excitation. We show that in TNT and RDX vibrational bands that couple to NO2 or the ring are particularly resonance enhanced. Finally, the computed RDX spectra of the conformers present a benchmark for understanding the RR spectra of the solid-phase polymorphs of RDX.

  16. Investigations of the intermolecular forces between RDX and polyethylene by force-distance spectroscopy and molecular dynamics simulations.

    Taylor, D E; Strawhecker, K E; Shanholtz, E R; Sorescu, D C; Sausa, R C


    The development of novel nanoenergetic materials with enhanced bulk properties requires an understanding of the intermolecular interactions occurring between molecular components. We investigate the surface interactions between 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and polyethylene (PE) crystals on the basis of combined use of molecular dynamics (MD) simulations and force-distance spectroscopy, in conjunction with Lifshitz macroscopic theory of van der Waals forces between continuous materials. The binding energy in the RDX-PE system depends both on the degree of PE crystallinity and on the RDX crystal face. Our MD simulations yield binding energies of approximately 132 and 120 mJ/m(2) for 100% amorphous and 100% crystalline PE on RDX (210), respectively. The average value is about 36% greater than our experimental value of 81 ± 15 mJ/m(2) for PE (∼48% amorphous) on RDX (210). By comparison, Liftshitz theory predicts a value of about 79 mJ/m(2) for PE interacting with RDX. Our MD simulations also predict larger binding energies for both amorphous and crystalline PE on RDX (210) compared to the RDX (001) surface. Analysis of the interaction potential indicates that about 60% of the binding energy in the PE-RDX system is due to attractive interactions between HPE-ORDX and CPE-NRDX pairs of atoms. Further, amorphous PE shows a much longer interaction distance than crystalline PE with the (210) and (001) RDX surfaces due to the possibility of larger polymer elongations in the case of amorphous PE as strain is applied. Also, we report estimates of the binding energies of energetic materials RDX and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) with PE, propylene, polystyrene, and several fluorine-containing polymers using Lifshitz theory and compare these with reported MD calculations.

  17. CdS/Cu纳米光催化剂降解废水中的HMX和RDX试验研究%Photocatalytic Degradation of HMX and RDX Wastewater with CdS/Cu Nanophotocatalyst

    Hamid Reza Pouretedal; Mohammad Hossien Keshavarz; Mohammad Hasan Yosefi; Arash Shokrollahi; Abbas Zali


    The wastewater with HMX and RDX was treated by photodegradation process in the presence of cadmium sulfide doped with copper as photocatalyst under UV and Vis irradiations. The influence on the degration of Cu% as dopant in CdS/Cu nanoparticles, pH of solution, dosage of photocatalyst and concentration of explosives were studied. The XRD patterns and UV-Vis spectra were used to characterize the nanoparticle. Results show that the degradation efficiency for HMX and RDX wastewater reaches 85%-88% in the presence of Cd0.95Cu0.05S under 180 min UV irradiation. The dosage of 160.0 mg·L-1 of photocatalyst and the pH of 7 are the optimum. A gradual decrease in degradation at the first two cycles is seen.

  18. Phylogenetic and Metabolic Diversity of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming Bacteria in Strictly Anaerobic Mixed Cultures Enriched on RDX as Nitrogen Source


    the Enterobacteriaceae family ( Klebsiella pneumoniae, Serratia marcescens, Morganella morganii, Citrobacter freundii, and Escherichia coli) [10,11... wastewater to methane (70% of the total gas released). The following compounds were added to the basic salts and vitamins medium to enrich bacteria using RDX...RDX biodegradation by a methanogenic enrichment culture obtained from an explosives man- ufacturing wastewater treatment plant. Technical report, pp. 99

  19. Recovery of RDX and AlPowderin Discarded or Obsolete TNT/RDX/Al Explosive by Solvent Extraction%溶剂萃取法回收废旧梯黑铝炸药中的RDX和铝粉

    吴翼; 丁玉奎; 刘国庆; 王海丹; 姬文苏


    According to different solubility of TNT and RDX in solvent in the mixed explosive,TNT in discarded or obsolete TNT/RDX/Al explosive was extracted first with toluene as solvent and then acetone and DMSO were chosen as the extraction solvents of RDX,and RDX was obtained by filtration through cooling and crystallizing the RDX solution.The morphology characteristics and thermal analysis of reclaimed RDX were performed by SEM and DSC. Phase analysis of reclaimed Al powder was carried out by XRD.The results show that the purities of RDX recrystal-ized from acetone and DMSO are 98.4% and 97.8%,respectively.The crystal quality of RDX recrystalized from acetone is better than that of RDX recrystalized from DMSO.The impact sensitivities of RDX recrystalized from acetone and DMSO are 76% and 84%,respectively.The characteristic temperatures of raw material RDX and reclaimed RDX were basically the same and the thermal stability of reclaimed RDX is good.Reclaimed Al powder does not contain explosives and has no obvious oxidation.%利用混合炸药中TNT和RDX在溶剂中溶解度的差异,首先用甲苯萃取出梯黑铝炸药中的TNT,然后分别以丙酮和二甲基亚砜为溶剂,经萃取、冷却结晶,过滤得到RDX。用SEM和DSC对回收RDX进行形貌表征和热分析,用XRD对回收铝粉进行物相分析。结果表明,丙酮和二甲基亚砜中重结晶回收 RDX 的纯度分别为98.4%和97.8%,撞击感度分别为76%和84%,丙酮重结晶回收RDX晶体质量优于二甲基亚砜重结晶回收的RDX。回收RDX与原料RDX的特征温度基本相同,热安定性良好;回收的铝粉不含炸药,无明显氧化。

  20. Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments.

    Ariyarathna, Thivanka; Vlahos, Penny; Smith, Richard W; Fallis, Stephen; Groshens, Thomas; Tobias, Craig


    The lack of knowledge on the fate of explosive compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), particularly in marine ecosystems, constrains the application of bioremediation techniques in explosive-contaminated coastal sites. The authors present a comparative study on anaerobic biodegradation and mineralization of (15) N-nitro group isotopically labeled TNT and RDX in organic carbon-rich, fine-grained marine sediment with native microbial assemblages. Separate sediment slurry experiments were carried out for TNT and RDX at 23°C for 16 d. Dissolved and sediment-sorbed fractions of parent and transformation products, isotopic compositions of sediment, and mineralization products of the dissolved inorganic N pool ((15) NH4(+) ,(15) NO3(-) ,(15) NO2(-) , and (15) N2 ) were measured. The rate of TNT removal from the aqueous phase was faster (0.75 h(-1) ) than that of RDX (0.37 h(-1) ), and (15) N accumulation in sediment was higher in the TNT (13%) than the RDX (2%) microcosms. Mono-amino-dinitrotoluenes were identified as intermediate biodegradation products of TNT. Two percent of the total spiked TNT-N is mineralized to dissolved inorganic N through 2 different pathways: denitration as well as deamination and formation of NH4(+) , facilitated by iron and sulfate reducing bacteria in the sediments. The majority of the spiked TNT-N (85%) is in unidentified pools by day 16. Hexahydro-1,3,5-trinitro-1,3,5-triazine (10%) biodegrades to nitroso derivatives, whereas 13% of RDX-N in nitro groups is mineralized to dissolved inorganic N anaerobically by the end of the experiment. The primary identified mineralization end product of RDX (40%) is NH4(+) , generated through either deamination or mono-denitration, followed by ring breakdown. A reasonable production of N2 gas (13%) was seen in the RDX system but not in the TNT system. Sixty-eight percent of the total spiked RDX-N is in an unidentified pool by day 16 and may include

  1. Absorption spectroscopy of RDX monopropellant flames: CN and NH concentrations

    Homan, B. E.; Vanderhoff, John A.


    UV-visible multi-channel absorption spectroscopy has been used to probe the self-sustained combustion of pressed RDX, a main energetic ingredient found in modern day propellants and explosives. The two dimensional feature of an intensified CCD detector allowed simultaneous recording of multiple, spatially distinct absorption spectra. Between 10 and 12 equally spaced absorption spectra with spatial resolution as small as 0.163 mm have been obtained during 1 ms exposure. The number of absorption spectra and the spatial resolution can easily be set by the detector software, size of the excitation sheet and the focal length of the collection lens. Temporal resolution in the UV region has been increased to 1 ms by pulsing the light source. A 0.54 joule pulse with a duration of 0.75 ms was added to a simmering Xenon arc lamp for the measurement of combustion species. The increase in light intensity of 30 and 70 times the non-pulsed output provided the necessary light flux to achieve single pulse, multiple absorption spectra. To increase the species concentration sensitivity of the experiment, a triple pass optical arrangement was adopted. Partially silvered windows were installed at an angle to the beam providing for three passes across the samples. The corresponding path length was increased by a factor of 2.8 times the sample diameter. Least squares analysis of absorption spectra provide mole fraction profiles for OH, CN and NH along with temperature. Profiles for NC and HN have been determined for self-sustained combustion of RDX in 1.0, 1.5 and 2.0 atm air. Peak CN mole fractions of about 200 ppm are observed at 1 atm pressure and the NH mole fraction is about a factor of two lower. As the pressure is increased the reactive CN and HN species peak closer to the combusting surface and reside over a smaller spatial extent. Peak concentrations drop for these higher pressures, but may be due, at least in part, to limitations of the spatial resolution of the absorption

  2. PDADN-RDX-CMDB推进剂催化燃烧特性研究%Catalysis combustion property and mechanism of PDADN-RDX-CMDB propellant

    李疏芬; 王进; 赵凤起; 王瑛; 许煜; 李上文


    采用热分析、微热电偶技术、燃速测试、熄火表面的扫描电镜观测等实验方法,研究了不同类型的复合催化剂对PDADN-RDX-CMDB推进剂燃烧特性的影响。结果发现,邻苯二甲酸铅/雷索辛酸铜/炭黑与雷索辛酸铅铜/炭黑两类复合催化剂可较好地改善PDADN-RDX-CMDB推进剂的燃烧特性,明显降低其压强指数且同时提高燃速,基于实验现象的观测结果分析,提出了"气泡-凝聚相反应"理论,解释了该类推进剂在中低压区发生的"超速燃烧"现象。%In order to study effects of several kinds of composite catalysts on the combustion behavior of PDADN-RDX-CMDB propellant,different means such as thermogravimetric loss,microthermo couple,burning-rate experiment and SEM of quenched sample surface were adopted.The results show that two kinds of composite catalysts,which are ΦPb-βCu-CB and βPbCu-CB,can obviously improve the combustion behavior of PDADN-RDX-CMDB propellant,combustion pressure exponent are decreased and burning-rate are increased.The "bubble-condensation reaction" theory are proposed to explain "super rate combustion" phenomenon of PDADN-RDX-CMDB with composite catalysts propellant.

  3. Phylogenetic and metabolic diversity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-transforming bacteria in strictly anaerobic mixed cultures enriched on RDX as nitrogen source.

    Zhao, Jian-Shen; Spain, Jim; Hawari, Jalal


    Five obligate anaerobes that were most closely related to Clostridium bifermentans, Clostridium celerecrescens, Clostridium saccharolyticum, Clostridium butyricum and Desulfovibrio desulfuricans by their 16S rRNA genes sequences were isolated from enrichment cultures using hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as a nitrogen source. The above isolates transformed RDX at rates of 24.0, 5.4, 6.2, 2.5, 5.5 mumol h(-1) g (dry weight) of cells(-1), respectively, to nitrite, formaldehyde, methanol, and nitrous oxide. The present results indicate that clostridia are major strains responsible for RDX removal, and all isolates seemed to mainly transform RDX via its initial reduction to MNX and subsequent denitration. Since clostridia are commonly present in soil, we suggest that they may contribute to the removal of RDX in the subsurface (anoxic) soil.

  4. Synthesis and Characterization of High Energy Sheet Materials Based on HMX / RDX and Hydroxyl Terminated Polybutadiene

    Elsharkawy, Karim; Guo, Lin; Taha, Elhussein; Fouda, Hany


    In this paper three types of thin sheets of highly energetic materials were prepared and characterized. The first based on 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). The second type based on 1,3,5-trinitro-1,3,5-triazinane (RDX). Both types contain polyurethane (PU), formulated by hydroxyl terminated polybutadiene (HTPB) and Isophorondiisocyanate (IPDI). The third type based on (RDX) and polyisoprene (PI) as high elastomeric material. The first and second types of thin sheets were prepared by applying the casting technique while the third type was prepared by slurry technique then followed by rolling of the prepared beads of the RDX coated by PI. These high energy sheet materials were cured in oven at 60°C. The measured explosive properties of the prepared sheets were discussed and showed that the sensitivity to impact and friction of the prepared sheets explosives materials were markedly decreased when compared to pure HMX or pure RDX, but the sensitivity to heat was close to that of pure RDX. In spite of the markedly decrease in the sensitivity of these sheets, the explosive characteristics were nearly not affected the sheets have very good stress-strain values.

  5. Sublimation kinetics and diffusion coefficients of TNT, PETN, and RDX in air by thermogravimetry.

    Hikal, Walid M; Weeks, Brandon L


    The diffusion coefficients of explosives are crucial in their trace detection and lifetime estimation. We report on the experimental values of diffusion coefficients of three of the most important explosives in both military and industry: TNT, PETN, and RDX. Thermogravimetric analysis (TGA) was used to determine the sublimation rates of TNT, PETN, and RDX powders in the form of cylindrical billets. The TGA was calibrated using ferrocene as a standard material of well-characterized sublimation rates and vapor pressures to determine the vapor pressures of TNT, PETN, and RDX. The determined sublimation rates and vapor pressures were used to indirectly determine the diffusion coefficients of TNT, PETN, and RDX for the first time. A linear log-log dependence of the diffusion coefficients on temperature is observed for the three materials. The diffusion coefficients of TNT, PETN, and RDX at 273 K were determined to be 5.76×10(-6)m(2)/sec, 4.94×10(-6)m(2)/s, and 5.89×10(-6)m(2)/s, respectively. Values are in excellent agreement with the theoretical values in literature. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Autosomal Recessive Nonsyndromic Hearing Impairment due to a Novel Deletion in the RDX Gene

    Kwanghyuk Lee


    Full Text Available The RDX gene anchors cytoskeletal actin of stereocilia to hair cell transmembrane and is responsible for autosomal recessive nonsyndromic hearing impairment (ARNSHI due to DFNB24. A genome scan was performed using DNA samples from a consanguineous Pakistani family with ARNSHI. A significant maximum two-point LOD score of 4.5 (θ=0 and multipoint LOD score of 5.8 were achieved at marker D11S1998 (chr11 : 117.20 Mb. The region of homozygosity is bounded by markers D11S2000 (105.06 Mb and D11S4464 (123.13 Mb and contains the NSHI genes TECTA and RDX. Although no potentially causal variants were identified in the TECTA gene, within the RDX gene a novel deletion c.1076_1079delTTAA (p.Ile359Lysfs*6 was identified. The RDX deletion segregates with ARNSHI within the family and was not observed in 500 control chromosomes. It is predicted to cause premature truncation of radixin at the α-helical domain and to result in nonfunctional transcripts within the cochlea. RDX isoforms which encode the coiled-coil region of the α-helical domain are deemed necessary for proper function of hair cell stereocilia.

  7. Involvement of cytochrome c CymA in the anaerobic metabolism of RDX by Shewanella oneidensis MR-1.

    Perreault, Nancy N; Crocker, Fiona H; Indest, Karl J; Hawari, Jalal


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a cyclic nitramine explosive commonly used for military applications that is responsible for severe soil and groundwater contamination. In this study, Shewanella oneidensis MR-1 was shown to efficiently degrade RDX anaerobically (3.5 µmol·h(-1)·(g protein)(-1)) via two initial routes: (1) sequential N-NO(2) reductions to the corresponding nitroso (N-NO) derivatives (94% of initial RDX degradation) and (2) denitration followed by ring cleavage. To identify genes involved in the anaerobic metabolism of RDX, a library of ~2500 mutants of MR-1 was constructed by random transposon mutagenesis and screened for mutants with a reduced ability to degrade RDX compared with the wild type. An RDX-defective mutant (C9) was isolated that had the transposon inserted in the c-type cytochrome gene cymA. C9 transformed RDX at ~10% of the wild-type rate, with degradation occurring mostly via early ring cleavage caused by initial denitration leading to the formation of methylenedinitramine, 4-nitro-2,4-diazabutanal, formaldehyde, nitrous oxide, and ammonia. Genetic complementation of mutant C9 restored the wild-type phenotype, providing evidence that electron transport components have a role in the anaerobic reduction of RDX by MR-1.

  8. Ultraviolet Laser-induced ignition of RDX single crystal

    Yan, Zhonghua; Zhang, Chuanchao; Liu, Wei; Li, Jinshan; Huang, Ming; Wang, Xuming; Zhou, Guorui; Tan, Bisheng; Yang, Zongwei; Li, Zhijie; Li, Li; Yan, Hongwei; Yuan, Xiaodong; Zu, Xiaotao


    The RDX single crystals are ignited by ultraviolet laser (355 nm, 6.4 ns) pulses. The laser-induced damage morphology consisted of two distinct regions: a core region of layered fracture and a peripheral region of stripped material surrounding the core. As laser fluence increases, the area of the whole crack region increases all the way, while both the area and depth of the core region increase firstly, and then stay stable over the laser fluence of 12 J/cm2. The experimental details indicate the dynamics during laser ignition process. Plasma fireball of high temperature and pressure occurs firstly, followed by the micro-explosions on the (210) surface, and finally shock waves propagate through the materials to further strip materials outside and yield in-depth cracks in larger surrounding region. The plasma fireball evolves from isotropic to anisotropic under higher laser fluence resulting in the damage expansion only in lateral direction while maintaining the fixed depth. The primary insights into the interaction dynamics between laser and energetic materials can help developing the superior laser ignition technique.

  9. Effects of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in zebrafish: General and reproductive toxicity

    Mukhi, S.; Patino, R.


    Mixed-sex populations of young adult zebrafish (???2-month-old) were exposed to measured RDX concentrations of 0, 1 or 9.6 ppm for up to 12 weeks followed by a 15-day rearing period in untreated water. RDX caused high mortality at 9.6 ppm, with most deaths occurring within the first 8 weeks of exposure. RDX at 9.6 ppm caused lower body weights at 4 and 8 weeks of exposure; and at 1 ppm, lower body weight was observed only at 4 weeks. Fish length was not affected by treatment at any time during the exposure period. The bioconcentration factor for RDX seemed to be influenced by time of exposure but not by water RDX concentration; its overall values were 1.01 ?? 0.13, 0.91 ?? 0.06 and 2.23 ?? 0.04 at 4, 8 weeks and 12 weeks, respectively. RDX was not detected in fish collected after the 15-day recovery period. In a separate experiment, adult females and males were separately exposed to RDX at measured concentrations of 0, 0.5 and 3.2 ppm for a period of 6 weeks. Reproductive performance was evaluated by biweekly breeding of the fish and measuring packed-egg volume (PEV) as index of fecundity. At 0.5 ppm, RDX caused elevated PEV levels relative to the control value at 2 weeks but not at 4 or 6 weeks, whereas no significant effects were noted at 3.2 ppm. Egg fertilization and embryo hatching rates were not affected by RDX at any of the concentrations tested. In conclusion, RDX at sublethal concentrations causes short-term negative effects on growth and, at 0.5 ppm, positive effects on fecundity. ?? 2008 Elsevier Ltd.

  10. Biochemical and microbial analysis of ovine rumen fluid incubated with 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX).

    Perumbakkam, Sudeep; Craig, A Morrie


    In this study, the rumen was assessed for its potential to detoxify RDX using molecular microbial ecology as well as analytical chemistry techniques. Results indicated significant loss (P RDX in RDX (M-O + HCOO) and methylenedinitramine metabolites. A total of 1106 16S rRNA-V3 clones were sequenced, and most sequences associated with either the phyla Bacteroidetes or Firmicutes. A LibCompare analysis for the RDX treatment showed an enrichment (P RDX, and the members of the genus Prevotella are linked to this detoxification.

  11. A coarse-grain force field for RDX: Density dependent and energy conserving

    Moore, Joshua D.; Barnes, Brian C.; Izvekov, Sergei; Lísal, Martin; Sellers, Michael S.; Taylor, DeCarlos E.; Brennan, John K.


    We describe the development of a density-dependent transferable coarse-grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one-site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions.

  12. Bioremediation of RDX in the vadose zone beneath the Pantex Plant

    Shull, T.L.; Speitel, G.E. Jr.; McKinney, D.C. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering


    The presence of dissolved high explosives (HE), in particular RDX and HMX, is well documented in the perched aquifer beneath the Pantex Plant, but the distribution of HE in the vadose zone has not yet been well defined. Although current remediation activities focus on the contamination in the perched aquifer, eventually regulatory concern is likely to turn to the residual contamination in the vadose zone. Sources of HE include the infiltration of past wastewater discharges from several HE-processing facilities through the ditch drainage system and leachate from former Landfill 3. With limited existing data on the HE distribution in the vadose zone and without preventive action, it must be assumed that residual HE could be leached into infiltrating water, providing a continuing supply of contamination to the perched aquifer. The purpose of this project was to more closely examine the fate and transport of HE in the vadose zone through mathematical modeling and laboratory experimentation. In particular, this report focuses on biodegradation as one possible fate of HE. Biodegradation of RDX in the vadose zone was studied because it is both present in highest concentration and is likely to be of the greatest regulatory concern. This study had several objectives: determine if indigenous soil organisms are capable of RDX biodegradation; determine the impact of electron acceptor availability and nutrient addition on RDX biodegradation; determine the extent of RDX mineralization (i.e., conversion to inorganic carbon) during biodegradation; and estimate the kinetics of RDX biodegradation to provide information for mathematical modeling of fate and transport.

  13. Uptake of munitions materiels (TNT, RDX) by crop plants and potential interactions of nitrogen nutrition

    Fellows, R.J.; Harvey, S.D.; Cataldo, D.A. [Pacific Northwest Lab., Richland, WA (United States); Mitchell, W. [USABRDL, Ft. Detrick, MD (United States)


    Munitions materiel such as trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and their combustion/decomposition products can accumulate/cycle in terrestrial environs. High soil organic matter and fertility have been previously shown to negatively correlate with both TNT or RDX uptake in plants such as grass, wheat, and bean. The present study was therefore conducted using low fertility soil to assess uptake and distribution patterns of C-radiolabelled TNT and RDX (15 and 30 {micro}g/g) within corn (Zea mays), spinach (Spinacea oleraceae), carrot (Daucus carota), and alfalfa (Medicago sativa) grown to maturity in growth chambers. Uptake by the plants at maturity (90- to 120-days) ranged from 1.8 to 2.7% of total amended {sup 14}C-TNT for carrots and corn respectively and 17 to 33% of total amended {sup 14}C-RDX for corn and carrots respectively. Distribution patterns of total radiolabel indicate that the TNT-derived label was primarily retained within the roots (60 to 85%) while the RDX-derived label was distributed to the shoots (85 to 97%). Less than 0.01 {micro}g/g dry wt. TNT was found in all analyzed shoot tissues with > 90% of the TNT-derived radiolabel in the form of polar metabolites. Concentrations of RDX in shoot tissues of corn exceeded 180 {micro}g/g dry wt. Alfalfa grown in unfertilized, fertilized (NO{sub 3}), or unfertilized-inoculated (Rhizobia) soil exhibited a 70 to 100% increase in dry wt. after 45 days in the TNT-amended (15 {micro}g/g) fertilized and unfertilized-inoculated plants versus the controls. A potential TNT/nitrogen interaction will be discussed.

  14. Field demonstration of on-site analytical methods for TNT and RDX in ground water

    Craig, H. [Environmental Protection Agency Region 10, Portland, OR (United States); Ferguson, G.; Markos, A. [Black and Veatch Special Projects Corp., Tacoma, WA (United States); Kusterbeck, A.; Shriver-Lake, L. [Naval Research Lab., Washington, DC (United States). Center for Bio/Molecular Science and Engineering; Jenkins, T.; Thorne, P. [Army Corps of Engineers, Hanover, NH (United States). Cold Regions Research and Engineering Lab.


    A field demonstration was conducted to assess the performance of eight commercially-available and emerging colorimetric, immunoassay, and biosensor on-site analytical methods for explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in ground water and leachate at the Umatilla Army Depot Activity, Hermiston, Oregon and US Naval Submarine Base, Bangor, Washington, Superfund sites. Ground water samples were analyzed by each of the on-site methods and results compared to laboratory analysis using high performance liquid chromatography (HPLC) with EPA SW-846 Method 8330. The commercial methods evaluated include the EnSys, Inc., TNT and RDX colorimetric test kits (EPA SW-846 Methods 8515 and 8510) with a solid phase extraction (SPE) step, the DTECH/EM Science TNT and RDX immunoassay test kits (EPA SW-846 Methods 4050 and 4051), and the Ohmicron TNT immunoassay test kit. The emerging methods tested include the antibody-based Naval Research Laboratory (NRL) Continuous Flow Immunosensor (CFI) for TNT and RDX, and the Fiber Optic Biosensor (FOB) for TNT. Accuracy of the on-site methods were evaluated using linear regression analysis and relative percent difference (RPD) comparison criteria. Over the range of conditions tested, the colorimetric methods for TNT and RDX showed the highest accuracy of the emerging methods for TNT and RDX. The colorimetric method was selected for routine ground water monitoring at the Umatilla site, and further field testing on the NRL CFI and FOB biosensors will continue at both Superfund sites.

  15. Integrated Data Collection Analysis (IDCA) Program - RDX Standard Data Set 2

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Phillips, Jason J. [Air Force Research Lab. (AFRL), Tyndall Air Force Base, FL (United States); Shelley, Timothy J. [Applied Research Associates, Tyndall Air Force Base, FL (United States); Reyes, Jose A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of the RDX Type II Class 5 standard, from testing the second time in the Proficiency Test. This RDX testing (Set 2) compared to the first (Set 1) was found to have about the same impact sensitivity, have more BAM friction sensitivity, less ABL friction sensitivity, similar ESD sensitivity, and same DSC sensitivity.

  16. Critical Analysis of Nitramine Decomposition Data: Product Distributions from HMX and RDX Decomposition


    unimolecular ring cleavage. It should be 106H.L. Pugh, L.P. Davis, J.S. Wllkes, W.R. Carper , and R.C. Dorey, "Thermal Decomposition of RDX Below the...603, 1933. 105 106. H.L. Pugh, L.P. Davis, J.S. Wilkes, W.R. Carper , and R.C. Dorey, "Thermal Decomposition of RDX Below the Melting Point...Los Alamos, NM 87545 University of California, Santa Barbara Quantum Institute ATTN: K. Schofield M. Steinberg Santa Barbara , CA 93106

  17. Nonadiabatic decomposition of gas-phase RDX through conical intersections: an ONIOM-CASSCF study.

    Bhattacharya, A; Bernstein, E R


    Topographical exploration of nonadiabatically coupled ground- and excited-electronic-state potential energy surfaces (PESs) of the isolated RDX molecule was performed using the ONIOM methodology: Computational results were compared and contrasted with the previous experimental results for the decomposition of this nitramine energetic material following electronic excitation. One of the N-NO(2) moieties of the RDX molecule was considered to be an active site. Electronic excitation of RDX was assumed to be localized in the active site, which was treated with the CASSCF algorithm. The influence of the remainder of the molecule on the chosen active site was calculated by either a UFF MM or RHF QM method. Nitro-nitrite isomerization was predicted to be a major excited-electronic-state decomposition channel for the RDX molecule. This prediction directly corroborates previous experimental results obtained through photofragmentation-fragment detection techniques. Nitro-nitrite isomerization of RDX was found to occur through a series of conical intersections (CIs) and was finally predicted to produce rotationally cold but vibrationally hot distributions of NO products, also in good agreement with the experimental observation of rovibrational distributions of the NO product. The ONIOM (CASSCF:UFF) methodology predicts that the final step in the RDX dissociation occurs on its S(0) ground-electronic-state potential energy surface (PES). Thus, the present work clearly indicates that the ONIOM method, coupled with a suitable CASSCF method for the active site of the molecule, at which electronic excitation is assumed to be localized, can predict hitherto unexplored excited-electronic-state PESs of large energetic molecules such as RDX, HMX, and CL-20. A comparison of the decomposition mechanism for excited-electronic-state dimethylnitramine (DMNA), a simple analogue molecule of nitramine energetic materials, with that for RDX, an energetic material, was also performed. CASSCF

  18. Identification of microbial populations assimilating nitrogen from RDX in munitions contaminated military training range soils by high sensitivity stable isotope probing.

    Andeer, Peter; Stahl, David A; Lillis, Lorraine; Strand, Stuart E


    The leaching of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) from particulates deposited in live-fire military training range soils contributes to significant pollution of groundwater. In situ microbial degradation has been proposed as a viable method for onsite containment of RDX. However, there is only a single report of RDX degradation in training range soils and the soil microbial communities involved in RDX degradation were not identified. Here we demonstrate aerobic RDX degradation in soils taken from a target area of an Eglin Air Force Base bombing range, C52N Cat's Eye, (Eglin, Florida U.S.A.). RDX-degradation activity was spatially heterogeneous (found in less than 30% of initial target area field samples) and dependent upon the addition of exogenous carbon sources to the soils. Therefore, biostimulation (with exogenous carbon sources) and bioaugmentation may be necessary to sustain timely and effective in situ microbial biodegradation of RDX. High sensitivity stable isotope probing analysis of extracted soils incubated with fully labeled (15)N-RDX revealed several organisms with (15)N-labeled DNA during RDX-degradation, including xplA-bearing organisms. Rhodococcus was the most prominent genus in the RDX-degrading soil slurries and was completely labeled with (15)N-nitrogen from the RDX. Rhodococcus and Williamsia species isolated from these soils were capable of using RDX as a sole nitrogen source and possessed the genes xplB and xplA associated with RDX-degradation, indicating these genes may be suitable genetic biomarkers for assessing RDX degradation potential in soils. Other highly labeled species were primarily Proteobacteria, including: Mesorhizobium sp., Variovorax sp., and Rhizobium sp.

  19. Research on Combustion Mechanism of RDX-CMDB Propellants with or without Catalysts%含催化剂RDX-CMDB推进剂燃烧机理研究

    赵凤起; 李丽; 李上文; 阴翠梅; 王瑛



  20. Ovine ruminal microbes are capable of biotransforming hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Eaton, H L; De Lorme, M; Chaney, R L; Craig, A M


    Bioremediation is of great interest in the detoxification of soil contaminated with residues from explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Although there are numerous forms of in situ and ex situ bioremediation, ruminants would provide the option of an in situ bioreactor that could be transported to the site of contamination. Bovine rumen fluid has been previously shown to transform 2,4,6-trinitrotoluene (TNT), a similar compound, in 4 h. In this study, RDX incubated in whole ovine rumen fluid was nearly eliminated within 4 h. Whole ovine rumen fluid was then inoculated into five different types of media to select for archaeal and bacterial organisms capable of RDX biotransformation. Cultures containing 30 μg mL(-1) RDX were transferred each time the RDX concentration decreased to 5 μg mL(-1) or less. Time point samples were analyzed for RDX biotransformation by HPLC. The two fastest transforming enrichments were in methanogenic and low nitrogen basal media. After 21 days, DNA was extracted from all enrichments able to partially or completely transform RDX in 7 days or less. To understand microbial diversity, 16S rRNA-gene-targeted denaturing gradient gel electrophoresis (DGGE) fingerprinting was conducted. Cloning and sequencing of partial 16S rRNA fragments were performed on both low nitrogen basal and methanogenic media enrichments. Phylogenetic analysis revealed similar homologies to eight different bacterial and one archaeal genera classified under the phyla Firmicutes, Actinobacteria, and Euryarchaeota. After continuing enrichment for RDX degraders for 1 year, two consortia remained: one that transformed RDX in 4 days and one which had slowed after 2 months of transfers without RDX. DGGE comparison of the slower transforming consortium to the faster one showed identical banding patterns except one band. Homology matches to clones from the two consortia identified the same uncultured Clostridia genus in both; Sporanaerobacter

  1. Detection and Analysis of Cyclotrimethylenetrinitramine (RDX) in Environmental Samples by Surface-Enhanced Raman Spectroscopy


    concentration represents the standard deviation determined using the method by Skoog et al.[47] Our results represent the first use of SERS to detect RDX in a...Wiley & Sons, Ltd. 1 1 3 6 N. A. Hatab et al. [46] W. A. MacCrehan, Anal. Chem. 2009, 81, 7189. [47] D. A. Skoog , D

  2. Calculation of the vibrational spectra of α-rdx using the grimme DFT potential

    Perger, Warren; Slough, William J.; Valenzano, Loredana; Flurchick, K. M.


    The density-functional theory (DFT) potential by Grimme has been proposed for describing longrange dispersion corrections. This potential has been implemented into the CRYSTAL09 program and used to calculate the vibrational spectra in α-RDX at equilibrium. The frequencies and intensities are reported and compared with prior theory and experiment where possible.

  3. Evaluation of microbial transport during aerobic bioaugmentation of an RDX-contaminated aquifer.

    Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Hancock, Dawn E; Fuller, Mark E; Hatzinger, Paul B; Vainberg, Simon; Istok, Jonathan D; Wilson, Edward; Michalsen, Mandy M


    In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp. KTR9 (xplA (+); i.e. wild-type) were conducted at UMCD. Groundwater monitoring evaluated cell viability and migration in the injection well and downgradient monitoring wells. Enhanced degradation of RDX was not evaluated in these demonstrations. Quantitative PCR analysis of xplA, the kanamycin resistance gene (aph), and xenB indicated that the mixed culture was transported at least 3 m within 2 h of injection. During a subsequent field injection of bioaugmented groundwater, strain KTR9 (wild-type) migrated up to 23-m downgradient of the injection well within 3 days. Thus, the three RDX-degrading strains were effectively introduced and transported within the UMCD aquifer. This demonstration represents an innovative application of bioaugmentation to potentially enhance RDX biodegradation in aerobic aquifers.

  4. The influence of a solvent on the crystal morphology of RDX

    Horst, J.H. ter; Geertman, R.M.; Heijden, A.E.D.M. van der; Rosmalen, G.M. van


    A solvent can have a large influence on the crystal morphology. A molecular modeling technique based on the adsorption of solvent molecules on a crystal surface has been used to predict the influence of a solvent on the morphology of RDX. The predicted morphology has been compared with the

  5. Characterization of granular and polymer-embedded RDX grades: Floret tests

    Heijden, A.E.D.M. van der; Bouma, R.H.B.


    In an attempt to further contribute to the characterization of explosive compositions, small scale Floret tests were performed using four RDX grades, differing in product quality. A Floret test provides a measure – by indentation of a copper block – of detonation spreading or the initiability and


    Soil and water contamination by the military munitions explosives TNT (2,4.6-trinitrotoluene)and RDX (1,3,5-hexahydro-1,3,5-trinitrotriazine)and their degradation products have raised many public health and environmental concerns. Phytoremediation techniques could provide a potential cost-effective...

  7. The influence of a solvent on the crystal morphology of RDX

    Horst, J.H. ter; Geertman, R.M.; Heijden, A.E.D.M. van der; Rosmalen, G.M. van


    A solvent can have a large influence on the crystal morphology. A molecular modeling technique based on the adsorption of solvent molecules on a crystal surface has been used to predict the influence of a solvent on the morphology of RDX. The predicted morphology has been compared with the experimen

  8. The mutation of the rdxA gene in metronidazole-resistant Helicobacter pylori clinical isolates

    Nasrin Mirzaei


    Conclusion: An interesting finding in metronidazole-resistant strains in our study was the detection of one mutation not previously described in the literature in the rdxA gene and this W(209R substitution presumably plays a role in inducing metronidazole resistance.

  9. DNTF/RDX-CMDB推进剂低温力学性能%Mechanical Properties for DNTF/RDX-CMDB Propellants at Low Temperature

    肖玮; 李亮亮; 王江宁; 苏健军; 王世英; 董树南; 屈可朋


    用单轴抗拉实验、动态力学分析仪和简支梁抗冲实验研究了不同3,4-二硝基呋咱基氧化呋咱( DNTF)/ RDX 配比对DNTF/RDX改性双基( CMDB)推进剂( DNTF/RDX-CMDB,DFR推进剂)力学性能的影响。获得了-40℃下 DFR 推进剂的抗拉强度(σm )、断裂延伸率(εm )及抗冲强度( aK )。根据“时间-温度”等效原理的 WLF方程获得了 DFR推进剂β松弛阶段的动态特征量黏弹系数(Cg1)。分析了组分含量对各力学性能的影响和σm、εm 的变化规律。结果表明:低温下的σm、εm 和 aK 均与增塑剂含量间存在相关性。增塑剂含量减小,粘弹系数增加,NC分子侧基的“自由体积”下降,导致抗拉强度、断裂延伸率等力学性能降低。%Influence of different ratios of 1,3,5-trinitrohexahydrotriazine(RDX)to 3,4-bisnitrofurazan-furoxan(DNTF)on the me-chanical properties of DNTF/RDX composite modified double-base( CMDB)propellant( DNTF/RDX-CMDB,DFR propellant) was studied by uniaxial tensile test,charpy impact test and dynamic mechanical analyzer. The tensile strength(σm ),elongation at the maximum stress(εm )and impact strength( aK )of DFR propellant at -40 ℃ were obtained. The dynamical characteristics (viscoelastic coefficients Cg1)of β-relaxation was acquired by WLF equation according to the“Time-Temperature”equivalence principle. The effect of plasticizer content on the various mechanical properties and change rule of σm and εm were analyzed, showing that a good correlation between σm ,εm ,aK at low temperature and plasticizer content. The plasticizer content reducing, Cg1 increasing,“free volume of side group of NC molecule”decreasing make the mechanical performances(σm and εm )worsen.

  10. Molecular simulations of adsorption of RDX and TATP on IRMOF-1(Be).

    Scott, Andrea Michalkova; Petrova, Tetyana; Odbadrakh, Khorgolkhuu; Nicholson, Donald M; Fuentes-Cabrera, Miguel; Lewis, James P; Hill, Frances C; Leszczynski, Jerzy


    The influence of different sorption sites of isoreticular metal-organic frameworks (IRMOFs) on interactions with explosive molecules is investigated. Different connector effects are taken into account by choosing IRMOF-1(Be) (IRMOF-1 with Zn replaced by Be), and two high explosive molecules: 1,3,5-trinitro-s-triazine (RDX) and triacetone triperoxide (TATP). The key interaction features (structural, electronic and energetic) of selected contaminants were analyzed by means of density functional calculations. The interaction of RDX and TATP with different IRMOF-1(Be) fragments is studied. The results show that physisorption is favored and occurs due to hydrogen bonding, which involves the C-H groups of both molecules and the carbonyl oxygen atoms of IRMOF-1(Be). Additional stabilization of RDX and TATP arises from weak electrostatic interactions. Interaction with IRMOF-1(Be) fragments leads to polarization of the target molecules. Of the molecular configurations we have studied, the Be-O-C cluster connected with six benzene linkers (1,4-benzenedicarboxylate, BDC), possesses the highest binding energy for the studied explosives (-16.4 kcal mol(-1) for RDX and -12.9 kcal mol(-1) for TATP). The main difference was discovered to be in the preferable adsorption site for adsorbates (RDX above the small and TATP placed above the big cage). Based on these results, IRMOF-1 can be suggested as an effective material for storage and also for separation of similar explosives. Hydration destabilizes most of the studied adsorption systems by 1-3 kcal mol(-1) but it leads to the same trend in the binding strength as found for the non-hydrated complexes.

  11. Spectrophotometric analyses of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in water.

    Shi, Cong; Xu, Zhonghou; Smolinski, Benjamin L; Arienti, Per M; O'Connor, Gregory; Meng, Xiaoguang


    A simple and accurate spectrophotometric method for on-site analysis of royal demolition explosive (RDX) in water samples was developed based on the Berthelot reaction. The sensitivity and accuracy of an existing spectrophotometric method was improved by: replacing toxic chemicals with more stable and safer reagents; optimizing the reagent dose and reaction time; improving color stability; and eliminating the interference from inorganic nitrogen compounds in water samples. Cation and anion exchange resin cartridges were developed and used for sample pretreatment to eliminate the effect of ammonia and nitrate on RDX analyses. The detection limit of the method was determined to be 100 μg/L. The method was used successfully for analysis of RDX in untreated industrial wastewater samples. It can be used for on-site monitoring of RDX in wastewater for early detection of chemical spills and failure of wastewater treatment systems. Copyright © 2015. Published by Elsevier B.V.

  12. Photobiological transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using Rhodobacter sphaeroides.

    Millerick, Kayleigh A; Johnston, Juliet T; Finneran, Kevin T


    Pump-and-treat strategies for groundwater containing explosives may be necessary when the contaminated water approaches sensitive receptors. This project investigated bacterial photosynthesis as a strategy for ex situ treatment, using light as the primary energy source to facilitate RDX transformation. The objective was to characterize the ability of photosynthetic Rhodobacter sphaeroides (strain ATCC(®) 17023 ™) to transform the high-energy explosive RDX. R. sphaeroides transformed 30 μM RDX within 40 h under light conditions; RDX was not fully transformed in the dark (non-photosynthetic conditions), suggesting that photosynthetic electron transfer was the primary mechanism. Experiments with RDX demonstrated that succinate and malate were the most effective electron donors for photosynthesis, but glycerol was also utilized as a photosynthetic electron donor. RDX was transformed irrespective of the presence of carbon dioxide. The electron shuttling compound anthraquinone-2,6-disulfonate (AQDS) increased transformation kinetics in the absence of CO2, when the cells had excess NADPH that needed to be re-oxidized because there was limited CO2 for carbon fixation. When CO2 was added, the cells generated more biomass, and AQDS had no stimulatory effect. End products indicated that RDX carbon became CO2, biomass, and a soluble, uncharacterized aqueous metabolite, determined using (14)C-labeled RDX. These data are the first to suggest that photobiological explosives transformation is possible and will provide a framework for which phototrophy can be used in environmental restoration of explosives contaminated water. Copyright © 2016. Published by Elsevier Ltd.

  13. Development of a Relative Source Contribution Factor for Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)


    literature search was initiated and completed in mid-2007 for scientific articles related to RDX. Computerized searches for peer-reviewed literature...According to these authors, a Pathology Working Group (PWG) reviewed the reevaluation and arrived at a consensus classification of each lesion . Based on...representative fruits and vegetables ranged from 0.06–79 for food crops grown on RDX- contaminated soil (see Appendix C). Since the range covers several orders of

  14. Role of Nitrogen Limitation in Transformation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Gordonia sp. Strain KTR9

    Hancock, Dawn E.; Jung, Carina M.; Eberly, Jed O.; Mohn, William W.; Eltis, Lindsay D.; Crocker, Fiona H.


    The transcriptome of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)-degrading strain Gordonia sp. strain KTR9 and its glnR mutant were studied as a function of nitrogen availability to further investigate the observed ammonium-mediated inhibition of RDX degradation. The results indicate that nitrogen availability is a major determinant of RDX degradation and xplA gene expression in KTR9. PMID:23275513

  15. Cosubstrate independent mineralization of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a Desulfovibrio species under anaerobic conditions.

    Arnett, Clint M; Adrian, Neal R


    Past handling practices associated with the manufacturing and processing of the high explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has resulted in extensive environmental contamination. In-situ biodegradation is a promising technology for remediating RDX contaminated sites but often relies on the addition of a cosubstrate. A sulfate-reducing bacterium isolated from an RDX-degrading enrichment culture was studied for its ability to grow on RDX as a sole source of carbon and nitrogen and for its ability to mineralize RDX in the absence of a cosubstrate. The results showed the isolate degraded 140 muM RDX in 63 days when grown on RDX as a carbon source. Biomass within the carbon limited culture increased 9-fold compared to the RDX unamended controls. When the isolate was incubated with RDX as sole source of nitrogen it degraded 160 muM RDX in 41 days and exhibited a 4-fold increase in biomass compared to RDX unamended controls. Radiolabeled studies under carbon limiting conditions with (14)C-hexahydro-1,3,5-trinitro-1,3,5-triazine confirmed mineralization of the cyclic nitramine. After 60 days incubation 26% of the radiolabel was recovered as (14)CO(2), while in the control bottles less than 1% of the radiolabel was recovered as (14)CO(2). Additionally, approximately 2% of the radiolabeled carbon was found to be associated with the biomass. The 16S rDNA gene was sequenced and identified the isolate as a novel species of Desulfovibrio, having a 95.1% sequence similarity to Desulfovibrio desulfuricans. This is the first known anaerobic bacterium capable of mineralizing RDX when using it as a carbon and energy source for growth.

  16. Optical Properties of β-RDX Thin Films Deposited on Gold and Stainless Steel Substrates Calculated from Reflection-Absorption Infrared Spectra.

    Ruiz-Caballero, José L; Aparicio-Bolaño, Joaquín A; Figueroa-Navedo, Amanda M; Pacheco-Londoño, Leonardo C; Hernandez-Rivera, Samuel P


    The optical properties for crystalline films of the highly energetic material (HEM) hexahydro-1,3,5-trinitro-s-triazine, which is also known as RDX, deposited on gold (Au) and stainless steel (SS) substrates are presented. RDX has two important stable conformational polymorphs at room temperature: α-RDX and β-RDX. The optical properties obtained in the present work correspond to thin film samples of predominantly β-RDX polymorph. The infrared spectroscopic intensities measured showed significant differences in the β-RDX crystalline films deposited on the two substrates with respect to the calculated real part of refractive index. The β-RDX/Au crystalline films have a high dynamic response, which is characterized by the asymmetric stretching mode of the axial nitro groups, whereas for the β-RDX/SS crystalline films, the dynamic response was mediated by the -N-NO2 symmetric stretch mode. This result provides an idea of how the electric field vector propagates through the β-RDX crystalline films deposited on the two substrates.

  17. Reflection terahertz time-domain spectroscopy of RDX and HMX explosives

    Choi, Kyujin; Hong, Taeyoon; Ik Sim, Kyung; Ha, Taewoo; Cheol Park, Byung; Hyuk Chung, Jin; Gyeong Cho, Soo; Hoon Kim, Jae


    We report on our study of RDX and HMX, two of the most commonly used explosive materials, in bulk pellets with reflection terahertz time-domain spectroscopy in the frequency range of 0.3-3 THz. The maximum entropy method was utilized to correct our raw reflection data against the phase error due to the relative displacement between the sample and the reference. Both the refractive index n and the extinction coefficient k in the terahertz region were acquired for these two explosives without a Kramers-Kronig analysis. Both RDX and HMX exhibit a series of distinct peaks not quite detectable in the more conventional transmission-type measurements due to their high terahertz absorptivity. Our results are compared with the literature data on powder samples.

  18. Integrated Data Collection Analysis (IDCA) Program — RDX Standard Data Sets

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Phillips, Jason J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelley, Timothy J. [Bureau of Alcohol, Tobacco and Firearms, Huntsville, AL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of the RDX Type II Class 5 standard, for a third and fourth time in the Proficiency Test and averaged with the analysis results from the first and second time. The results, from averaging all four sets (1, 2, 3 and 4) of data suggest a material to have slightly more impact sensitivity, more BAM friction sensitivity, less ABL friction sensitivity, similar ESD sensitivity, and same DSC sensitivity, compared to the results from Set 1, which was used previously as the values for the RDX standard in IDCA Analysis Reports.

  19. Evaluation of the metabolic fate of munitions material (TNT & RDX) in plant systems and initial assessment of material interaction with plant genetic material. Validation of the metabolic fate of munitions materials (TNT, RDX) in mature crops

    Fellows, R.J.; Harvey, S.D.; Cataldo, D.A.


    The goals of this effort were to confirm and expand data related to the behavior and impacts of munitions residues upon human food chain components. Plant species employed included corn (Zea mays), alfalfa (Medicago sativa). spinach (Spinacea oleraceae), and carrot (Daucus carota). Plants were grown from seed to maturity (70 to 120 days) in a low-fertility soil (Burbank) amended with either {sup 14}C-TNT or {sup 14}C-RDX at which time they were harvested and analyzed for munitions uptake, partitioning, and chemical form of the munition or munition-metabolite. All four of the plant species used in this study accumulated the {sup 14}C-TNT- and RDX-derived label. The carrot, alfalfa, and corn demonstrated a higher percentage of label retained in the roots (62, 73, and 83% respectively). The spinach contained less activity in its root (36%) but also contained the highest TNT specific activity observed (>4600 jig TNT equivalents/g dry wt.). The specific uptake values of RDX for the spinach and alfalfa were comparable to those previously reported for wheat and bean (314 to 590 {mu}g RDX-equivalents/g dry wt. respectively). An exception to this may be the carrot where the specific activity was found to exceed 4200 {mu}g RDX-equivalents/g dry wt. in the shoot. The total accumulation of TNT by the plants ranged from 1.24% for the spinach to 2.34% for the carrot. The RDX plants ranging from 15% for the spinach to 37% for the carrot. There was no identifiable TNT or amino dinitrotoluene (ADNT) isomers present in the plants however, the parent RDX compound was found at significant levels in the shoot of alfalfa (> 1 80 {mu}g/g) and corn (>18 {mu}g/g).

  20. Toxicities of TNT and RDX to Terrestrial Plants in Five Soils with Contrasting Characteristics


    soils because the majority of plant dry matter consists of assimilates (i.e., carbohydrates , proteins , and lipids ) that are synthesized during...trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) for terrestrial plants. The physical and chemical properties of different soils may... Physical and Chemical Characteristics of Five Field Soils (n = 3) Soil Property TSL Soil SSL Soil KCL Soil RCL Soil WCL Soil Sand (%) 65 (1.0

  1. Computational Study of the Structure and Mechanical Properties of the Molecular Crystal RDX


    Thompson, D. L. Intermolecular Potential for the Hexahydro- 1,3,5-trinitro-1,3,5-s-triazine Crystal (RDX): A Crystal Packing, Monte Carlo, and...Molecular Dynamics Study. The Journal of Physical Chemistry B 1997, 101, 798–808. 40. Sewell, T. D.; Bennett, C. M. Monte Carlo Calculations of the...PDF INFORMATION CTR only) DTIC OCA 8725 JOHN J KINGMAN RD STE 0944 FORT BELVOIR VA 22060-6218 1 DIRECTOR US ARMY RESEARCH LAB

  2. New Approaches to Evaluate the Biological Degradation of RDX in Groundwater


    groundwater samples and groundwater microcosms derived from the same contaminated aquifer. Zhang and Hughes reported that Clostridium acetobutylicum ATCC 824...Wisconsin (9); Clostridium acetobutylicum ATCC 824 (75), American Type Culture Collection; Desulfovibrio sp. EFX-DES, Dr. Clint Arnett, U.S. Army Corps...RDX. The final three strains, Shewanella oneidensis MR-1, Clostridium acetobutylicum ATCC 824,and Clostridium bifermentans HAW-1were selected

  3. Role of Myelofibrosis in Hematotoxicity of Munition RDX Environmental Degradation Product MNX


    consequence of anemia in the absence of sufficient regeneration from bone marrow erythroid precursors is recruitment of extramedullatory sites of...Another event associated with a successful regeneration of an anemic episode is increased reticulocytes in the peripheral blood. We quantitated...planned. Statistics: Effects of MNX and RDX on endpoints with normally distributed data ( EPO , BUN, liver weights) were determined by ANOVA with post

  4. Reactant ion chemistry for detection of TNT, RDX, and PETN using an ion mobility spectrometer

    Klassen, S.E.; Rodacy, P.; Silva, R.


    This report describes the responses of three energetic materials (TNT, RDX, and PETN) to varying reactant ion chemistries and IMS cell temperatures. The following reactant ion chemistries were evaluated; air-dry; air-wet; methylene chloride-dry; methylene chloride-wet; methylene bromide-dry; nitrogen dioxide-wet; sulfur dioxide-wet. The temperature was varied between 160 - 220{degrees}C.

  5. Terahertz Spectra of Molecular Clusters of RDX, PETN, and TNT Calculated by Density Functional Theory


    to crystallographic structure conditions that would be associated with bulk material. In particular, the crystal structure of € α −RDX, whose CCDC ...PETN, whose CCDC reference code is PEYTN01, has been investigated by H. H. Cady, A. C. Larson (1975) [21]. The space group for this crystal structure...of TNT, whose CCDC reference code is ZZZMUC05, has been investigated by N. I. Golovina, A. N. Raevskii, L. O. Atovmyan (1994) [22]. The space group

  6. Critical Analysis of Nitramine Decomposition Data: Activation Energies and Frequency Factors for HMX and RDX Decomposition


    Condensed Phase Kinetics Constants," Thermochimica Acta , Vol. 9, p.444, 1974. 13 I. DSC curve of decomposing RDX. The gas-.phase material disappears...Smith, "Application of Scanning Calorimetry to the Study of Chemical Kinetics," Thermochimica Acta , Vol. I, p. 1, 1970. 2 1H. E. Kissinger, "Reaction...34Temperature Coefficient of Reaction," Thermochimica Acta , Vol. 28, p. 185, 1977. / 7 / 18 ...- .. ! / temperature dependence of a complex process

  7. Photolysis of RDX and nitroglycerin in the context of military training ranges.

    Bordeleau, Geneviève; Martel, Richard; Ampleman, Guy; Thiboutot, Sonia


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and nitroglycerin (NG) are two energetic materials commonly found in the environment on military training ranges. They are deposited on the ground in the form of solid particles, which can then dissolve in infiltration water or in surface water bodies. The objective of this study was to evaluate whether photolysis by sunlight can significantly contribute to the natural attenuation of RDX and NG (as solid particles or dissolved in surface water) at mid-northern latitudes, where training ranges of Canada and many European countries are located. Experiments conducted at 46.9°N show that both compounds are degraded by sunlight when dissolved in water, with half-lives between 1 and 120d, depending on the compound and time of year. Numerical models may be useful in predicting such photolysis rates, but the models should take into account current ozone levels, as older radiation datasets, collected before the ozone depletion observed since the late 1970s, underestimate the RDX/NG photolysis rate. For solid RDX or NG-bearing particles, photolysis is slower (half-lives of 2-4months), but the degradation rate is still rapid enough to make this process significant in a natural attenuation context. However, photolysis of NG embedded within solid propellant particles cannot proceed to completion, due to the stable nitrocellulose matrix of the propellant. Nonetheless, photolysis clearly constitutes an important attenuation mechanism that should be considered in conceptual models and included in numerical modeling efforts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Lon protease affects the RdxA nitroreductase activity and metronidazole susceptibility in Helicobacter pylori.

    Tu, I-Fan; Liao, Jiahn-Haur; Yang, Feng-Ling; Lin, Nien-Tsung; Chan, Hong-Lin; Wu, Shih-Hsiung


    The lon gene of Helicobacter pylori strains is constitutively expressed during growth. However, virtually nothing is understood concerning the role of Lon in H. pylori. This study examined the function and physiological role of Lon in H. pylori (HpLon) using a trapping approach to identify putative Lon binding partners in the bacterium. Protease-deficient Lon was expressed and served as the bait in trapping approach to capture the interacting partners in H. pylori. The antibiotic susceptibility of wild-type and lon derivative mutants was determined by the E test trips and the disc diffusion assay. The effect of HpLon on RdxA activity was detected the change in NADPH oxidation and metronidazole reduction by spectrophotometer. Lon in Helicobacter pylori (HpLon) interacting partners are mostly associated with metronidazole activation. lon mutant presents more susceptible to metronidazole than that of the wild type, and this phenotype is recovered by complementation of the wild-type Lon. We found that the ATPases associated with a variety of cellular activities (AAA(+) ) module of HpLon causes a decrease in both NADPH oxidase and Mtz reductase activity in RdxA, a major Mtz-activating enzyme in H. pylori. Metronidazole resistance of H. pylori causes the serious medical problem worldwide. In this study, HpLon is involved in metronidazole susceptibility among H. pylori strains. We provide the evidence that HpLon alters RdxA activity in vitro. The decrease in metronidazole activation caused by HpLon is possibly prior to accumulate mutation in rdxA gene before the metronidazole-resistant strains to be occurred. © 2014 John Wiley & Sons Ltd.

  9. Characterization of the Morphology of RDX Particles Formed by Laser Ablation


    laser-ablated particle sizes. ...................4 Figure 3. SEM images of laser-ablated M43 propellant grain at (a) 150× magnification and (b) 500...Experimental Method 2.1 Materials The energetic materials studied included an M43 propellant grain that consists of ~76% RDX, 12% cellulose acetate...butyrate (CAB), 8% plasticizer, and 4% nitrocellulose (NC) (26). Class-1 ( m) and class-5 (ឝ m) military-grade and research-grade (i.e

  10. Evaluation of Uncertainty in Constituent Input Parameters for Modeling the Fate of RDX


    accurately estimated, such as solubility, while others — such as degradation rates — are often far more uncertain . Prior to using improved methods this purpose, a previous application of TREECS™ was used to evaluate parameter sensitivity and the effects of highly uncertain inputs for...than others. One of the most uncertain inputs in this application is the loading rate (grams/year) of unexploded RDX residue. A value of 1.5 kg/yr was

  11. Phase-field modeling of shock-induced α- γ phase transformation of RDX

    Rahul, -; de, Suvranu


    A thermodynamically consistent continuum phase field model has been developed to investigate the role of shock-induced α- γ phase transition in the sensitivity of RDX. Dislocations and phase transformations are distinguished and modeled within a crystal plasticity framework. The Landau potential is derived for the finite elastic deformation analysis. The response of the shock loaded RDX crystal is obtained by solving the continuum momentum equation along with phase evolution equation using a Helmholtz free energy functional, which consists of elastic potential energy and local interfacial energy that follows from the Cahn-Hilliard formalism. We observe that the orientations for which there is a resolved shear stress along the slip direction, the material absorbs large shear strain through plastic deformation, allowing it to be less sensitive as less mechanical work is available for temperature rise. Therefore, plastic slip should be associated with greater shear relaxation and, hence, decreased sensitivity. For elastic orientations, large shear stress arises from steric hindrance that may provides much more mechanical work to increase the temperature and hence more sensitive to detonation. Our simulations suggest that the α- γ phase transformation in RDX may be associated with the increased temperature rise and hence the shock sensitivity. The authors gratefully acknowledge the support of this work through Office of Naval Research (ONR) Grants N000140810462 and N000141210527 with Dr. Clifford Bedford as the cognizant Program Manager.

  12. Trace Detection of RDX, HMX and PETN Explosives Using a Fluorescence Spot Sensor

    Wang, Chen; Huang, Helin; Bunes, Benjamin R.; Wu, Na; Xu, Miao; Yang, Xiaomei; Yu, Li; Zang, Ling


    1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and pentaerythritol tetranitrate (PETN), the major components in plastic explosives, pose a significant threat to public safety. A quick, sensitive, and low-cost detection method for these non-volatile explosives is eagerly demanded. Here we present a fluo-spot approach, which can be employed for in situ detection of trace amount of explosives. The sensor molecule is a charge-transfer fluorophore, DCM, which is strongly fluorescent in its pristine state, but non-fluorescent after the quick reaction with NO2· (or NO2+) generated from the UV photolysis of RDX, HMX (or PETN). When fabricated within silica gel TLC plate, the fluo-spot sensor features high sensitivity owing to the large surface area and porous structure of the substrate. The sensor reaction mechanism was verified by various experimental characterizations, including chromatography, UV-Vis absorption and fluorescence spectroscopy, MS and 1H NMR spectrometry. The fluo-spot also demonstrated high selectivity towards RDX, HMX and PETN, as no significant fluorescence quenching was observed for other chemical compounds including common nitro-aromatic explosives and inorganic oxidative compounds. The DCM sensor can also be used as an economical spray kit to directly spot the explosives by naked eyes, implying great potential for quick, low-cost trace explosives detection.


    SI H. LEE


    Full Text Available Demilitarization requires the recovery and disposal of obsolete ammunition and explosives. Since open burning/detonation of hazardous waste has caused serious environmental and safety problems, thermal decomposition has emerged as one of the most feasible methods. RDX is widely used as a military explosive due to its high melting temperature and detonation power. In this work, the feasible conditions under which explosives can be safely incinerated have been investigated via a rotary kiln simulation. To solve this problem, phase change along with the reactions of RDX has been incisively analyzed. A global reaction mechanism consisting of condensed phase and gas phase reactions are used in Computational Fluid Dynamics simulation. User Defined Functions in FLUENT is utilized in this study to inculcate the reactions and phase change into the simulation. The results divulge the effect of temperature and the varying amounts of gas produced in the rotary kiln during the thermal decomposition of RDX. The result leads to the prospect of demilitarizing waste explosives to avoid the possibility of detonation.

  14. The mutation of the rdxA gene in metronidazole-resistant Helicobacter pylori clinical isolates.

    Mirzaei, Nasrin; Poursina, Farkhondeh; Moghim, Sharareh; Rahimi, Ebrahim; Safaei, Hajieh Ghasemian


    Antibiotic resistance is an increasing problem throughout the developed world, and knowledge about different resistance mechanisms is consequential for efficient treatment of bacterial infections. Although metronidazole has been frequently used in treatment regimens for H. pylori infection, but antibiotic resistance is now a major contributing factor in treatment failure. Nevertheless metronidazole has been greatly used as a critical component of combination therapies for H. pylori infection. This study is trying to describe the mutational mechanisms of metronidazole resistance in H. pylori in our clinical isolates in Isfahanian patients, Iran and compare with the findings of previous studies in world. MIC values of metronidazole for H. pylori strains were determined by E- test. Both rdxA and glmM genes used for confirmation of isolates as H. pylori and then amplification of another rdxA oligonucleotide pair was done. Finally, the six resistant strains were sent to sequencing for other processing and further analysis was done by software. The result of six clinical isolates in comparison with 26695, J99 and 69A as a sensitive and resistant reference strains showed plenty of mutations. No frame shift and nonsense mutation was seen in our clinical isolates. An interesting finding in metronidazole-resistant strains in our study was the detection of one mutation not previously described in the literature in the rdxA gene and this W(209)R substitution presumably plays a role in inducing metronidazole resistance.

  15. Phase transition, thermodynamics properties and IR spectrum of α- and γ-RDX: First principles and MD studies

    Yuan, Jiaonan; Ji, Guangfu; Chen, Xiangrong; Wei, Dongqing; Zhao, Feng; Wu, Qiang


    In present letter, based on density functional theory plus dispersion (DFT-D) and a self-consistent charge density-functional tight-binding (SCC-DFTB) method, the structural and electronic properties are reported, and the phase transition are investigated by analyzing its thermodynamics properties and IR spectrum of RDX. The anisotropy of α- and γ-RDX were discussed at 0⿿10 GPa. By fitting the third-order Birch⿿Murnaghan equation of states, the bulk modulus and its pressure derivative of RDX were determined. The α-RDX phase is found stable at ambient condition, however, under pressures, both the values of lattice constants a, b, c and the οEvdw at around 4 GPa show abrupt changes which indicate a structural transition occurred. By analyzing the linear compressibility of a, b, c axes at 0⿿8 GPa, one clearly see that the molecules in α-RDX phase underwent rotations and translational motion to their position in the γ-RDX phase at about 4 GPa, which validates the α⿿γ phase transition. The IR spectra of α-form and γ-form RDX was calculated by analyzing the trajectory of molecules motion, which also show the phase transition from the spectra changes. Employing the quasi-harmonic Debye model, the enthalpy and specific heat were investigated at various pressures of both phases. The condition of equal enthalpies in both phases also indicates the phase transition of α-form to γ-form at around 4 GPa. The variation of specific heat with temperature approaches to the classical Dulong⿿Petit's law at high temperature, while at low-temperature it obeys the Debye's T3 law.

  16. Geochemical and microbiological processes contributing to the transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in contaminated aquifer material.

    Kwon, Man Jae; O'Loughlin, Edward J; Antonopoulos, Dionysios A; Finneran, Kevin T


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a potential human carcinogen, and its contamination of subsurface environments is a significant threat to public health. This study investigated abiotic and biological degradation of RDX in contaminated aquifer material. Anoxic batch systems were started with and without pre-aeration of aquifer material to distinguish initial biological RDX reduction from abiotic RDX reduction. Aerating the sediment eliminated chemical reductants in the native aquifer sediment, primarily Fe(II) sorbed to mineral surfaces. RDX (50 μM) was completely reduced and transformed to ring cleavage products when excess concentrations (2mM) of acetate or lactate were provided as the electron donor for aerated sediment. RDX was reduced concurrently with Fe(III) when acetate was provided, while RDX, Fe(III), and sulfate were reduced simultaneously with lactate amendment. Betaproteobacteria were the dominant microorganisms associated with RDX and Fe(III)/sulfate reduction. In particular, Rhodoferax spp. increased from 21% to 35% and from 28% to 60% after biostimulation by acetate and lactate, respectively. Rarefaction analyses demonstrated that microbial diversity decreased in electron-donor-amended systems with active RDX degradation. Although significant amounts of Fe(III) and/or sulfate were reduced after biostimulation, solid-phase reactive minerals such as magnetite or ferrous sulfides were not observed, suggesting that RDX reduction in the aquifer sediment is due to Fe(II) adsorbed to solid surfaces as a result of Fe(III)-reducing microbial activity. These results suggest that both biotic and abiotic processes play an important role in RDX reduction under in situ conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Ab Initio Calculations of the N-N Bond Dissociation for the Gas-phase RDX and HMX

    Liu, Lin-Lin; Liu, Pei-Jin; Hu, Song-Qi; He, Guo-Qiang


    NO2 fission is a vital factor for 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) decomposition. In this study, the geometry of the gas-phase RDX and HMX molecules was optimized, and the bond order and the bond dissociation energy of the N-N bonds were examined. Moreover, the rate constants of the gas-phase RDX and HMX conformers, concerning the N-N bond dissociation, were evaluated using the microcanonical variational transition state theory (μVT). The calculation results have shown that HMX is more stable than RDX in terms of the N-N bond dissociation, and the conformers stability parameters were as follows: RDXaaa HMX I HMX II. In addition, for the RDX conformers, the N-N bond of the pseudo-equatorial positioning of the nitro group was more stable than the N-N bond of the axial positioning of the nitro group, while the results were opposite in the case of the HMX conformers. Moreover, it has been shown that the dissociation rate constant of the N-N bond is influenced by the temperature significantly, thus the rate constants were much lower (<10-10 s-1) when the temperature was less than 1000 K.

  18. Insight on RDX degradation mechanism by Rhodococcus strains using 13C and 15N kinetic isotope effects.

    Bernstein, Anat; Ronen, Zeev; Gelman, Faina


    The explosive Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is known to be degraded aerobically by various isolates of the Rhodococcus species, with denitration being the key step, mediated by Cytochrome P450. Our study aimed at gaining insight into the RDX degradation mechanism by Rhodococcus species and comparing isotope effects associated with RDX degradation by distinct Rhodococcus strains. For these purposes, enrichment in (13)C and (15)N isotopes throughout RDX denitration was studied for three distinct Rhodococcus strains, isolated from soil and groundwater in an RDX-contaminated site. The observable (15)N enrichment throughout the reaction, together with minor (13)C enrichment, suggests that N-N bond cleavage is likely to be the key rate-limiting step in the reaction. The similarity in the kinetic (15)N isotope effect between the three tested strains suggests that either isotope-masking effects are negligible, or are of a similar extent for all tested strains. The lack of variability in the kinetic (15)N isotope effect allows the interpretation of environmental studies with greater confidence.

  19. The effect of polymer matrices on the thermal hazard properties of RDX-based PBXs by using model-free and combined kinetic analysis.

    Yan, Qi-Long; Zeman, Svatopluk; Sánchez Jiménez, P E; Zhao, Feng-Qi; Pérez-Maqueda, L A; Málek, Jiří


    In this paper, the decomposition reaction models and thermal hazard properties of 1,3,5-trinitro-1,3,5-triazinane (RDX) and its PBXs bonded by Formex P1, Semtex 1A, C4, Viton A and Fluorel polymer matrices have been investigated based on isoconversional and combined kinetic analysis methods. The established kinetic triplets are used to predict the constant decomposition rate temperature profiles, the critical radius for thermal explosion and isothermal behavior at a temperature of 82°C. It has been found that the effect of the polymer matrices on the decomposition mechanism of RDX is significant resulting in very different reaction models. The Formex P1, Semtex and C4 could make decomposition process of RDX follow a phase boundary controlled reaction mechanism, whereas the Viton A and Fluorel make its reaction model shifts to a two dimensional Avrami-Erofeev nucleation and growth model. According to isothermal simulations, the threshold cook-off time until loss of functionality at 82°C for RDX-C4 and RDX-FM is less than 500 days, while it is more than 700 days for the others. Unlike simulated isothermal curves, when considering the charge properties and heat of decomposition, RDX-FM and RDX-C4 are better than RDX-SE in storage safety at arbitrary surrounding temperature. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Subacute Toxicity of RDX and TNT in Monkeys


    SRed Blood Cells* 10-12 Negative SEithelinel Cells* Few Frequent ’ Bacteri a* Small Moderate - Anow7hnus Crystals* Moderate iPeavy Negative Negative...Negative Albuiin 30 mg Negative Ketone Negative Negative r Bile Negative Negative Occult Blood Negative :,fgative r, lhitIn "locJ Cells* 2-4 2-3 SRed

  1. 包覆改性RDX及其在CMDB推进剂中的应用❋%Coating of RDX and Its Application in CMDB Propellant

    杨雪芹; 常双君; 赵芦奎; 刘爱传; 高玉猛


    选用键合剂LBA-1和热塑性弹性体( TPE)对RDX进行表面包覆改性,并应用于CMDB推进剂中。采用扫描电子显微镜( SEM)表征了RDX包覆前后颗粒表面的变化情况,同时,分别测试了RDX包覆前后和制备的CMDB推进剂的摩擦感度和撞击感度,并且对含包覆RDX的CMDB推进剂的力学性能和燃烧性能进行了表征。结果表明,经包覆改性后降感效果均明显,其中键合剂包覆的RDX,摩擦感度降低了68%,对应的CMDB推进剂,摩擦感度降低了37.5%。两种材料包覆改性RDX对推进剂的力学性能均有明显的改善,其中经热塑性弹性体包覆改性后,RDX-CMDB推进剂的抗拉强度提高了4.72 MPa,延伸率提高了19.67%;对推进剂的燃烧性能有一定的影响。%RDX was surface coated and modified with bonding agent LBA-1and thermoplastic elastomer(TPE), and then was applied in the CMDB propellant. Scanning Electron Microscopy ( SEM) was used to characterize the particle sur-face of RDX before and after coating. The friction and impact sensitivities of the RDX before and after coating and RDX-CMDB propellant were studied. Furthermore, the combustion and mechanical properties of the RDX-CMDB propellant were characterized. The results show that, compared with the uncoated RDX, the friction sensitivity of the coated RDX with bonding agent and corresponding RDX-CMDB reduce by 68% and 37. 5%, respectively. What��s more, surface coated RDX had a significant effect on the mechanical properties of the propellant. For example, the tensile strength and elongation of the RDX-CMDB were increased by 4. 72 MPa and 19. 67%, respectively, after coating of RDX with thermoplastic elasto-mer;and RDX coated with these two materials also exhibited a certain effect on the combustion properties of the propellant.

  2. Al-RDX-CMDB推进剂燃烧催化机理和模型的研究%Study of Mechanism and Model for Catalyzed Combustion of Al-RDX-CMDB Propellant

    宋洪昌; 王祎; 白华萍



  3. 燃烧稳定剂对RDX-CMDB推进剂不稳定燃烧的抑制规律%Inhibiting Rule of Combustion Stabilizers on the Unstable Combustion of RDX-CMDB Propellant

    陈雪莉; 王瑛; 张佩


    用压力可控T形燃烧器研究了6种燃烧稳定剂ZrO2、WC、Al2O3、ZrB2、SiC和BN对RDX-CMDB推进剂不稳定燃烧的抑制规律,获得了压力耦合响应函数;讨论了不同压力及不同固有频率时燃烧稳定剂对推进剂燃烧稳定性的影响.结果表明,固有频率1700 Hz和800 Hz下,6种燃烧稳定剂对RDX-CMDB推进剂不稳定燃烧的抑制作用具有显著差异.固有频率800Hz时,ZrO2能够完全消除RDX-CMDB推进剂的不稳定燃烧;Al2O3仅在1.3 MPa左右出现压力振荡;WC、SiC对RDX-CMDB推进剂的不稳定燃烧抑制作用随含量不同抑振区间不同;ZrB2对RDX-CMDB推进剂的不稳定燃烧抑制效果不明显;而BN则在1.5 MPa有高的燃烧响应.固有频率1700 Hz时,6种燃烧稳定剂均降低了RDX-CMDB推进剂的压力耦合响应函数,但降幅不同,其中SiC的降幅最大,ZrB2降幅最小.

  4. Uptake and fate of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in coastal marine biota determined using a stable isotopic tracer, (15)N - [RDX].

    Ballentine, Mark L; Ariyarathna, Thivanka; Smith, Richard W; Cooper, Christopher; Vlahos, Penny; Fallis, Stephen; Groshens, Thomas J; Tobias, Craig


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is globally one of the most commonly used military explosives and environmental contaminant. (15)N labeled RDX was added into a mesocosm containing 9 different coastal marine species in a time series experiment to quantify the uptake of RDX and assess the RDX derived (15)N retention into biota tissue. The (15)N attributed to munitions compounds reached steady state concentrations ranging from 0.04 to 0.67 μg (15)N g dw(-1), the bulk (15)N tissue concentration for all species was 1-2 orders of magnitude higher suggesting a common mechanism or pathway of RDX biotransformation and retention of (15)N. A toxicokinetic model was created that described the (15)N uptake, elimination, and transformation rates. While modeled uptake rates were within previous published values, elimination rates were several orders of magnitude smaller than previous studies ranging from 0.05 to 0.7 days(-1). These small elimination rates were offset by high rates of retention of (15)N previously not measured. Bioconcentration factors and related aqueous:organism ratios of compounds and tracer calculated using different tracer and non-tracer methods yielded a broad range of values (0.35-101.6 mL g(-1)) that were largely method dependent. Despite the method-derived variability, all values were generally low and consistent with little bioaccumulation potential. The use of (15)N labeled RDX in this study indicates four possible explanations for the observed distribution of compounds and tracer; each with unique potential implications for possible toxicological impacts in the coastal marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Time-resolved spectroscopic measurements of shock-wave induced decomposition in cyclotrimethylene trinitramine (RDX) crystals: anisotropic response.

    Dang, Nhan C; Dreger, Zbigniew A; Gupta, Yogendra M; Hooks, Daniel E


    Plate impact experiments on the (210), (100), and (111) planes were performed to examine the role of crystalline anisotropy on the shock-induced decomposition of cyclotrimethylenetrinitramine (RDX) crystals. Time-resolved emission spectroscopy was used to probe the decomposition of single crystals shocked to peak stresses ranging between 7 and 20 GPa. Emission produced by decomposition intermediates was analyzed in terms of induction time to emission, emission intensity, and the emission spectra shapes as a function of stress and time. Utilizing these features, we found that the shock-induced decomposition of RDX crystals exhibits considerable anisotropy. Crystals shocked on the (210) and (100) planes were more sensitive to decomposition than crystals shocked on the (111) plane. The possible sources of the observed anisotropy are discussed with regard to the inelastic deformation mechanisms of shocked RDX. Our results suggest that, despite the anisotropy observed for shock initiation, decomposition pathways for all three orientations are similar.

  6. Dietary Exposure of Fathead Minnows to the Explosives TNT and RDX and to the Pesticide DDT using Contaminated Invertebrates

    Guilherme R. Lotufo


    Full Text Available Explosive compounds have been released into the environment during manufacturing, handling, and usage procedures. These compounds have been found to persist in the environment and potentially promote detrimental biological effects. The lack of research on bioaccumulation and bioconcentration and especially dietary transfer on aquatic life has resulted in challenges in assessing ecological risks. The objective of this study was to investigate the potential trophic transfer of the explosive compounds 2,4,6-trinitrotoluene (TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX using a realistic freshwater prey/predator model and using dichlorodiphenyltrichloroethane (DDT, a highly bioaccumulative compound, to establish relative dietary uptake potential. The oligochaete worm Lumbriculus variegatus was exposed to 14C-labeled TNT, RDX or DDT for 5 hours in water, frozen in meal-size packages and subsequently fed to individual juvenile fathead minnows (Pimephales promelas. Fish were sampled for body residue determination on days 1, 2, 3, 4, 7, and 14 following an 8-hour gut purging period. Extensive metabolism of the parent compound in worms occurred for TNT but not for RDX and DDT. Fish body residue remained relatively unchanged over time for TNT and RDX, but did not approach steady-state concentration for DDT during the exposure period. The bioaccumulation factor (concentration in fish relative to concentration in worms was 0.018, 0.010, and 0.422 g/g for TNT, RDX and DDT, respectively, confirming the expected relatively low bioaccumulative potential for TNT and RDX through the dietary route. The experimental design was deemed successful in determining the potential for trophic transfer of organic contaminants via a realistic predator/prey exposure scenario.

  7. TNT and RDX degradation and extraction from contaminated soil using subcritical water.

    Islam, Mohammad Nazrul; Shin, Moon-Su; Jo, Young-Tae; Park, Jeong-Hun


    The use of explosives either for industrial or military operations have resulted in the environmental pollution, poses ecological and health hazard. In this work, a subcritical water extraction (SCWE) process at laboratory scale was used at varying water temperature (100-175 °C) and flow rate (0.5-1.5 mL min(-1)), to treat 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soil, to reveal information with respect to the explosives removal (based on the analyses of soil residue after extraction), and degradation performance (based on the analyses of water extracts) of this process. Continuous flow subcritical water has been considered on removal of explosives to avoid the repartitioning of non-degraded compounds to the soil upon cooling which usually occurs in the batch system. In the SCWE experiments, near complete degradation of both TNT and RDX was observed at 175 °C based on analysis of water extracts and soil. Test results also indicated that TNT removal of >99% and a complete RDX removal were achieved by this process, when the operating conditions were 1 mL min(-1), and treatment time of 20 min, after the temperature reached 175 °C. HPLC-UV and ion chromatography analysis confirmed that the explosives underwent for degradation. The low concentration of explosives found in the process wastewater indicates that water recycling may be viable, to treat additional soil. Our results have shown in the remediation of explosives contaminated soil, the effectiveness of the continuous flow SCWE process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Monte Carlo calculations of the physical properties of RDX, {beta}-HMX, and TATB

    Sewell, T.D.


    Atomistic Monte Carlo simulations in the NpT ensemble are used to calculate the physical properties of crystalline RDX, {beta}-HMX, and TATB. Among the issues being considered are the effects of various treatments of the intermolecular potential, inclusion of intramolecular flexibility, and simulation size dependence of the results. Calculations of the density, lattice energy, and lattice parameters are made over a wide range of pressures; thereby allowing for predictions of the bulk and linear coefficients of isothermal expansion of the crystals. Comparison with experiment is made where possible.

  9. Conserved toxic responses across divergent phylogenetic lineages: a meta-analysis of the neurotoxic effects of RDX among multiple species using toxicogenomics.

    Garcia-Reyero, Natàlia; Habib, Tanwir; Pirooznia, Mehdi; Gust, Kurt A; Gong, Ping; Warner, Chris; Wilbanks, Mitchell; Perkins, Edward


    At military training sites, a variety of pollutants such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), may contaminate the area originating from used munitions. Studies investigating the mechanism of toxicity of RDX have shown that it affects the central nervous system causing seizures in humans and animals. Environmental pollutants such as RDX have the potential to affect many different species, therefore it is important to establish how phylogenetically distant species may respond to these types of emerging pollutants. In this paper, we have used a transcriptional network approach to compare and contrast the neurotoxic effects of RDX among five phylogenetically disparate species: rat (Sprague-Dawley), Northern bobwhite quail (Colinus virginianus), fathead minnow (Pimephales promelas), earthworm (Eisenia fetida), and coral (Acropora formosa). Pathway enrichment analysis indicated a conservation of RDX impacts on pathways related to neuronal function in rat, Northern bobwhite quail, fathead minnows and earthworm, but not in coral. As evolutionary distance increased common responses decreased with impacts on energy and metabolism dominating effects in coral. A neurotransmission related transcriptional network based on whole rat brain responses to RDX exposure was used to identify functionally related modules of genes, components of which were conserved across species depending upon evolutionary distance. Overall, the meta-analysis using genomic data of the effects of RDX on several species suggested a common and conserved mode of action of the chemical throughout phylogenetically remote organisms. © Springer Science+Business Media, LLC (outside the USA) 2011

  10. Fate of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in soil and bioaccumulation in bush bean hydroponic plants

    Harvey, S.D.; Fellows, R.J.; Cataldo, D.A.; Bean, R.M. (Pacific Northwest Lab., Richland, WA (United States))


    Soils amended with [[sup 14]C]hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were sampled over 60 d and subjected to exhaustive Soxhlet extraction followed by HPLC analysis. RDX was the only radiolabeled compound observed in soil extracts. Emission of volatile organics and [sup 14]CO[sub 2] from soil accounted for only 0.31 % of the amended radiolabel. Mass balance for RDX-amended soil was better than 84% throughout the two-month study. The analytical method developed for plants involved acid hydrolysis, solvent extraction, fractionation on Florisil adsorbent and separation by HPLC. The described methodology allowed for RDX recovery of 86 [+-] 3% from fortified bush bean leaf tissue. Further experiments were conducted with bush bean plants maintained on RDX-containing hydroponic solutions. Hydroponic plants did not emit detectable amounts of [sup 14]CO[sub 2] or radiolabeled volatile organics. Analysis of the plant tissue indicated bioaccumulation of RDX in the aerial tissues of hydroponic plants exposed for either 1 or 7 d. Metabolism of RDX to polar metabolites was observed in plants exposed for 7 d.

  11. Metabolism of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a contaminated vadose zone.

    Ronen, Zeev; Yanovich, Yuval; Goldin, Regina; Adar, Eilon


    The aim of this study was to explore biodegradation potential of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a deep contaminated unsaturated zone over Israel's coastal aquifer. While anaerobic biodegradation potential was observed throughout the profile down to the water table at a depth of 45 m, aerobic biodegradation was limited to the surface of the unsaturated zone. Traces of nitroso-RDX intermediates were detected in the soil samples, indicating possible in situ activity. Polymerase chain reaction and denaturing gradient gel electrophoresis analysis revealed that the microbial population in the soil consisted of protobacteria, but no known RDX degraders were detected. However, a 16S rRNA gene sequence most similar to Sphingomonas sp. was detected at all depths. Biodegradation rates were faster in the surface (0 and 1m) versus deeper soil samples (22 and 45 m) and were not affected under anaerobic conditions by the presence of nitrate, indicating a concurrent reduction of both compounds. RDX half-life in the surface soil was mostly dependent on carbon content and to lesser extent on soil moisture. Biomineralization of RDX to CO(2) was confirmed by incubating surface soil with (14)C-labeled RDX. An aerobic RDX-degrading bacterium, identified as Gordonia sp., was isolated from the soil: it degraded RDX aerobically and produced 4-nitro-2,4-diazabutanal. This study, the first to explore RDX biodegradation in the deep vadoze zone, indicates biodegradation potential throughout the profile, which is likely to support natural attenuation.

  12. Ag nanocluster/DNA hybrids: functional modules for the detection of nitroaromatic and RDX explosives.

    Enkin, Natalie; Sharon, Etery; Golub, Eyal; Willner, Itamar


    Luminescent Ag nanoclusters (NCs) stabilized by nucleic acids are implemented as optical labels for the detection of the explosives picric acid, trinitrotoluene (TNT), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The sensing modules consist of two parts, a nucleic acid with the nucleic acid-stabilized Ag NCs and a nucleic acid functionalized with electron-donating units, including L-DOPA, L-tyrosine and 6-hydroxy-L-DOPA, self-assembled on a nucleic acid scaffold. The formation of donor-acceptor complexes between the nitro-substituted explosives, exhibiting electron-acceptor properties, and the electron-donating sites, associated with the sensing modules, concentrates the explosives in close proximity to the Ag NCs. This leads to the electron-transfer quenching of the luminescence of the Ag NCs by the explosive molecule. The quenching of the luminescence of the Ag NCs provides a readout signal for the sensing process. The sensitivities of the analytical platforms are controlled by the electron-donating properties of the donor substituents, and 6-hydroxy-L-DOPA was found to be the most sensitive donor. Picric acid, TNT, and RDX are analyzed with detection limits corresponding to 5.2 × 10(-12) M, 1.0 × 10(-12) M, and 3.0 × 10(-12) M, respectively, using the 6-hydroxy-L-DOPA-modified Ag NCs sensing module.

  13. Pilot-scale in situ bioremediation of HMX and RDX in soil pore water in Hawaii.

    Payne, Zachary M; Lamichhane, Krishna M; Babcock, Roger W; Turnbull, Stephen J


    A nine-month in situ bioremediation study was conducted in Makua Military Reservation (MMR) in Oahu, Hawaii (USA) to evaluate the potential of molasses to enhance biodegradation of royal demolition explosive (RDX) and high-melting explosive (HMX) contaminated soil below the root zone. MMR has been in operation since the 1940's resulting in subsurface contamination that in some locations exceeds USEPA preliminary remediation goals for these chemicals. A molasses-water mixture (1 : 40 dilution) was applied to a treatment plot and clean water was applied to a control plot via seven flood irrigation events. Pore water samples were collected from 12 lysimeters installed at different depths in 3 boreholes in each test plot. The difference in mean concentrations of RDX in pore water samples from the two test plots was very highly significant (p nitrogen concentrations also differed significantly with treatment (p sensor (31 ft) within 5 days of application. Most of the molasses was consumed by soil microorganisms by about 13.5 feet below ground surface and treatment of deeper depths may require greater molasses concentrations and/or more frequent flood irrigation. Use of the bioremediation method described herein could allow the sustainable use of live fire training ranges by enhancing biodegradation of explosives in situ and preventing them from migrating to through the vadose zone to underlying ground water and off-site.

  14. Numerical analysis of thermal decomposition for RDX, TNT, and Composition B.

    Kim, Shin Hyuk; Nyande, Baggie W; Kim, Hyoun Soo; Park, Jung Su; Lee, Woo Jin; Oh, Min


    Demilitarization of waste explosives on a commercial scale has become an important issue in many countries, and this has created a need for research in this area. TNT, RDX and Composition B have been used as military explosives, and they are very sensitive to thermal shock. For the safe waste treatment of these high-energy and highly sensitive explosives, the most plausible candidate suggested has been thermal decomposition in a rotary kiln. This research examines the safe treatment of waste TNT, RDX and Composition B in a rotary kiln type incinerator with regard to suitable operating conditions. Thermal decomposition in this study includes melting, 3 condensed phase reactions in the liquid phase and 263 gas phase reactions. Rigorous mathematical modeling and dynamic simulation for thermal decomposition were carried out for analysis of dynamic behavior in the reactor. The results showed time transient changes of the temperature, components and mass of the explosives and comparisons were made for the 3 explosives. It was concluded that waste explosives subject to heat supplied by hot air at 523.15K were incinerated safely without any thermal detonation.

  15. Mirrored continuum and molecular scale simulations of the ignition of high-pressure phases of RDX

    Lee, Kibaek; Joshi, Kaushik; Chaudhuri, Santanu; Stewart, D. Scott


    We present a mirrored atomistic and continuum framework that is used to describe the ignition of energetic materials, and a high-pressure phase of RDX in particular. The continuum formulation uses meaningful averages of thermodynamic properties obtained from the atomistic simulation and a simplification of enormously complex reaction kinetics. In particular, components are identified based on molecular weight bin averages and our methodology assumes that both the averaged atomistic and continuum simulations are represented on the same time and length scales. The atomistic simulations of thermally initiated ignition of RDX are performed using reactive molecular dynamics (RMD). The continuum model is based on multi-component thermodynamics and uses a kinetics scheme that describes observed chemical changes of the averaged atomistic simulations. Thus the mirrored continuum simulations mimic the rapid change in pressure, temperature, and average molecular weight of species in the reactive mixture. This mirroring enables a new technique to simplify the chemistry obtained from reactive MD simulations while retaining the observed features and spatial and temporal scales from both the RMD and continuum model. The primary benefit of this approach is a potentially powerful, but familiar way to interpret the atomistic simulations and understand the chemical events and reaction rates. The approach is quite general and thus can provide a way to model chemistry based on atomistic simulations and extend the reach of those simulations.

  16. Numerical analysis of thermal decomposition for RDX, TNT, and Composition B

    Kim, Shin Hyuk; Nyande, Baggie W. [Department of Chemical Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 305-719 (Korea, Republic of); Kim, Hyoun Soo; Park, Jung Su [Agency for Defence Development, 462 Jochiwon-gil, Yuseong-gu, Daejeon 305-150 (Korea, Republic of); Lee, Woo Jin [Hanwha corporation, 117 Yeosusandan 3-ro, Yeosu-si, Jeollanam-do (Korea, Republic of); Oh, Min, E-mail: [Department of Chemical Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 305-719 (Korea, Republic of)


    Highlights: • Reaction mechanism of thermal decomposition of military explosives is investigated. • Mathematical modeling of thermal decomposition are executed. • Commercial scale reactor is employed for demilitarization of waste explosives. • Dynamic response of thermal decomposition is examined in a reactor. - Abstract: Demilitarization of waste explosives on a commercial scale has become an important issue in many countries, and this has created a need for research in this area. TNT, RDX and Composition B have been used as military explosives, and they are very sensitive to thermal shock. For the safe waste treatment of these high-energy and highly sensitive explosives, the most plausible candidate suggested has been thermal decomposition in a rotary kiln. This research examines the safe treatment of waste TNT, RDX and Composition B in a rotary kiln type incinerator with regard to suitable operating conditions. Thermal decomposition in this study includes melting, 3 condensed phase reactions in the liquid phase and 263 gas phase reactions. Rigorous mathematical modeling and dynamic simulation for thermal decomposition were carried out for analysis of dynamic behavior in the reactor. The results showed time transient changes of the temperature, components and mass of the explosives and comparisons were made for the 3 explosives. It was concluded that waste explosives subject to heat supplied by hot air at 523.15 K were incinerated safely without any thermal detonation.

  17. Determination of the HMX and RDX content in synthesized energetic material by HPLC, FT-MIR, and FT-NIR spectroscopies

    Mattos Elizabeth C.


    Full Text Available A new method has been developed for determining the content of mixtures of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, the HMX/RDX ratio, in explosive compositions by Fourier transform infrared spectroscopy (FT-IR, in the regions MIR (mid infrared and NIR (near infrared with reference values obtained by chromatographic analysis (HPLC. Plots of relative MIR (A917 / A783 or NIR absorbance values (A4412 / A4317 versus HMX/RDX ratio determined by HPLC analysis revealed good linear relationships.

  18. IRIS Toxicological Review of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) (Preliminary Assessment Materials)

    In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for RDX to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in c...

  19. IRIS Toxicological Review of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (Rdx) (Public Comment Draft)

    EPA is developing an Integrated Risk Information System (IRIS) assessment of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and has released the draft assessment for public comment. When final, the assessment will appear on the IRIS database.

  20. RDX binds to the convulsant site of the GABAA receptor and increases spontaneous firing rates of cortical neurons in vitro

    RDX (hexahydro-1 ,3,5-trinitro-1 ,3,5-triazine, hexogen, Royal Demolition eXplosive) is an explosive widely used by the military and has been found in soil and ground water in and surrounding training ranges, creating potential hazards to the environment and human health. Oral RD...

  1. Shock simulations of a single-site coarse-grain RDX model using the dissipative particle dynamics method with reactivity

    Sellers, Michael S.; Lísal, Martin; Schweigert, Igor; Larentzos, James P.; Brennan, John K.


    In discrete particle simulations, when an atomistic model is coarse-grained, a tradeoff is made: a boost in computational speed for a reduction in accuracy. The Dissipative Particle Dynamics (DPD) methods help to recover lost accuracy of the viscous and thermal properties, while giving back a relatively small amount of computational speed. Since its initial development for polymers, one of the most notable extensions of DPD has been the introduction of chemical reactivity, called DPD-RX. In 2007, Maillet, Soulard, and Stoltz introduced implicit chemical reactivity in DPD through the concept of particle reactors and simulated the decomposition of liquid nitromethane. We present an extended and generalized version of the DPD-RX method, and have applied it to solid hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Demonstration simulations of reacting RDX are performed under shock conditions using a recently developed single-site coarse-grain model and a reduced RDX decomposition mechanism. A description of the methods used to simulate RDX and its transition to hot product gases within DPD-RX is presented. Additionally, we discuss several examples of the effect of shock speed and microstructure on the corresponding material chemistry.

  2. IRIS Toxicological Review of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (Rdx) (External Review Draft)

    The IRIS Toxicological Review of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was released for external peer review in September 2016. The EPA’s Science Advisory Board’s (SAB) Chemical Assessment Advisory Committee (CAAC) will conduct a peer review of the scientific basis suppor...

  3. Identification of ovine ruminal microbes capable of biotransforming hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    Bioremediation is of great interest in the detoxification of soil contaminated with residues from explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Although there are numerous forms of in situ and ex situ bioremediation, ruminants would provide the option of an in situ bioreactor tha...

  4. Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) Simulations of the Molecular Crystal alphaRDX


    mass position. The black lines oriented in the [100] direction indicate the [100] interplanar thickness, d100 . Two separate layers, labeled b1 and b2...direction indicate the [100] interplanar thickness, d100 . Two separate layers, labeled b1 and b2, can be formed for αRDX as indicated in a) and shown

  5. Influence of carbon and metal oxide nanomaterials on aqueous concentrations of the munition constituents cyclotrimethylenetrinitramine (RDX) and tungsten.

    Brame, Jonathon A; Kennedy, Alan J; Lounds, Christopher D; Bednar, Anthony J; Alvarez, Pedro J J; Scott, Andrea M; Stanley, Jacob K


    There is an increasing likelihood of interactions between nanomaterials and munitions constituents in the environment resulting from the use of nanomaterials as additives to energetic formulations and potential contact in waste streams from production facilities and runoff from training ranges. The purpose of the present research was to determine the ability of nano-aluminum oxide (Al(2)O(3)) and multiwalled carbon nanotubes (MWCNTs) to adsorb the munitions constituents cyclotrimethylenetrinitramine (RDX) and tungsten (W) from aqueous solution as a first step in determining the long-term exposure, transport, and bioavailability implications of such interactions. The results indicate significant adsorption of RDX by MWCNTs and of W by nano-Al(2)O(3) (but not between W and MWCNT or RDX and nano-Al(2)O(3)). Kinetic sorption and desorption investigations indicated that the most sorption occurs nearly instantaneously (<5 min), with a relatively slower, secondary binding leading to statistically significant but relatively smaller increases in adsorption over 30 d. The RDX sorption that occurred during the initial interaction was irreversible, with long-term, reversible sorption likely the result of a secondary interaction; as interaction time increased, however, the portion of W irreversibly sorbed onto nano-Al(2)O(3) also increased. The present study shows that strong interactions between some munitions constituents and nanomaterials following environmental release are likely. Time-dependent binding has implications for the bioavailability, migration, transport, and fate of munitions constituents in the environment.

  6. Transformation of RDX and other energetic compounds by xenobiotic reductases XenA and XenB

    McClay, Kevin; Hawari, Jalal; Paquet, Louise; Malone, Thomas E.; Fox, Brian G.; Steffan, Robert J.


    The transformation of explosives, including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), by xenobiotic reductases XenA and XenB (and the bacterial strains harboring these enzymes) under both aerobic and anaerobic conditions was assessed. Under anaerobic conditions, Pseudomonas fluorescens I-C (XenB) degraded RDX faster than Pseudomonas putida II-B (XenA), and transformation occurred when the cells were supplied with sources of both carbon (succinate) and nitrogen (NH4+), but not when only carbon was supplied. Transformation was always faster under anaerobic conditions compared to aerobic conditions, with both enzymes exhibiting a O2 concentration-dependent inhibition of RDX transformation. The primary degradation pathway for RDX was conversion to methylenedinitramine and then to formaldehyde, but a minor pathway that produced 4-nitro-2,4-diazabutanal (NDAB) also appeared to be active during transformation by whole cells of P. putida II-B and purified XenA. Both XenA and XenB also degraded the related nitramine explosives octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane. Purified XenB was found to have a broader substrate range than XenA, degrading more of the explosive compounds examined in this study. The results show that these two xenobiotic reductases (and their respective bacterial strains) have the capacity to transform RDX as well as a wide variety of explosive compounds, especially under low oxygen concentrations. PMID:19455327

  7. RDX/AP-CMDB Propellants Containing Fullerenes and Carbon Black Additives

    X. Han


    Full Text Available The influence of fullerene additives on the combustion behaviour of cyclotrimethylene trinitramine/ammonium perchlorate composite modified double-base (RDX/AP-CMDB propellants are investigated by thermogravimetricdifferential thermogravimetric (TG-DTG analysis, burning rate tests, and scanning electron microscopy observations. The difference between lead salicylate (F-Pb and bismuth citrate acid (CP-Bi as combustion modifiers has also been examined. TG-DTG investigations show that the addition of all additives advanced and accelerated the evaporation of nitroglycerin (NG. The addition of Extracted Fullerene Soot (EFS, C60 and carbon black (CB additives obviously accelerated the liquid  phase decomposition of NG. Also, the solid phasedecomposition of nitrocellulose (NC and the liquid phase  decomposition of RDX were accelerated by 0.5 per cent Fullerene Soot (FS/2.5 per cent CP-Bi/0.5 per cent copper adipic acid (J-Cu composite catalyst. The addition of all composite catalysts promoted the decomposition of ammonium perchlorate (AP except 0.5 per cent EFS/2.5 per cent CP-Bi/0.5 per cent J-Cu composite catalysts. It is well known that there exists dark zone in the flame structure of RDX-CMDB propellant, but in our observation, the dark zone vanished with the addition of 10 per cent AP to the forenamed propellant. The burning rates were increased at low pressure but reduced at high pressure by all catalysts except 0.5 per cent EFS/2.5 per cent CP-Bi/0.5 per cent J-Cu and 0.5 per cent C60/2.5 per cent CP-Bi/0.5 per cent J-Cu which reduced the burning rates at every tested pressure. The pressure exponents of tested propellants were reduced by 0.5 per cent FS/2.5 per cent CP-Bi/0.5 per cent J-Cu with a factor of 17 per cent . The quenched surface observations significantly differed with the additions of diverse composite catalysts, which were consistent with the burning rate results.Defence Science Journal, 2009, 59(3, pp.284-293,

  8. Tandem mass spectrometry and density functional theory of RDX fragmentation pathways: Role of ion-molecule complexes in loss of NO3 and lack of molecular ion peak.

    Jeilani, Yassin A; Duncan, Kameron A; Newallo, Domnique S; Thompson, Albert N; Bose, Nripendra K


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is an explosive compound that finds a wide range of military and civilian applications. RDX has been a target in environmental matrices by gas chromatography/tandem mass spectrometry (GC/MS/MS). MS/MS in negative chemical ionization (NCI) mode of RDX provides important fragmentation patterns that are useful for structural elucidation. The fragmentation patterns are needed for proper identification of precursor and product ions in analytical methods that depend on MS/MS approaches for a reliable identification of RDX. This study focuses on the MS fragmentation mechanisms of RDX in NCI mode using both MS/MS and density functional theory (DFT). The DFT studies were performed at the B3LYP/6-311G(d,p) level of theory. The DFT results showed that NCI of RDX leads to the formation of an anion-molecule complex that was energetically more stable than the RDX anion. The fragmentation proceeds through two pathways, leading to the loss of NO(2) and NO(3). The loss of NO(3) takes place in an anion-molecule complex leading to the formation of characteristic nitroso group fragment ions. Using the fragmentation schemes, important ion structures are proposed including structures for m/z 160, 129, 102, and 86. The results demonstrate the importance of both charge-induced and charge-remote dissociations in RDX pathways. The ion structures identified along the pathways could be used as targets in analytical methods for reliable identification purposes. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Validation of a novel extraction method for studying hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) biodegradation by ruminal microbiota.

    Giarrizzo, J G; Murty, L; Tanaree, D; Walker, K; Craig, A M


    A simple, fast liquid-liquid extraction method was developed for studying hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) biodegradation using small sample volumes. The method was tested in vitro with anaerobic incubations of RDX with whole rumen fluid (WRF) and a commercial Sporanaerobacter acetigenes strain in methanogenic media for RDX. Additionally, validation experiments were conducted in deionized water in order to show applicability toward various aqueous matrices. Conditions for extraction were as follows: 300 μL of sample were mixed with an equal volume of a 0.34 M ammonium hydroxide solution to reach a basic pH, extracted with a hexane/ethyl acetate 1:1 (v/v) solution (1 mL) and shaken vigorously for 10 s. The resulting organic phase was transferred, then dried under a constant flow of N2 and reconstituted with acetonitrile (300 μL) for HPLC-UV and LC-MS/MS analysis. Percent recovery values were obtained (83-101%) in all matrices for RDX. In WRF (n=3 animals), RDX degradation was observed with almost 100% elimination of RDX after 4 h. The five nitroso and ring cleavage metabolites were observed by mass spectrometry. Liquid cultures of S. acetigenes did not show significant RDX biodegradation activity. RDX extractions from deionized water samples indicated acceptable recoveries with low variability, suggesting suitability of the method for aqueous matrices. Overall, the new method demonstrated acceptable efficiency and reproducibility across three matrices, providing an advantageous alternative for studies where complex matrices and small volume samples are in use. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Laboratory Studies and Preliminary Evaluation of Destructive Technologies for the Removal of RDX from the Water Waste Stream of Holston Army Ammunition Plan


    successfully demonstrated at the field scale as an in situ groundwater treatment (Wani et al. 2007) and as a water treatment system in upflow fluidized ... bed reactors (Atikovic et al. 2008). Iron and ferrous minerals have been demonstrated to degrade RDX in biologically active systems (Shrout et of both 200 W and 450 W (Ace Glass, Vineland, NJ). RDX-laden water circulated between the photochemical reactor and a 1-L mixed reservoir

  11. Effect of RDX and Al Contents on the Heat Explosion Temperature for RDX-based Aluminized Explosives%RDX和铝含量对RDX基含铝炸药热爆发温度的影响

    郑亚峰; 常海; 刘子如; 邵颖惠; 岳璞; 刘文亮


    The explosion temperatures Tb of 5 s delay for aluminized explosives of different RDX contents were determined by heat explosion test, and the effects of RDX and aluminum powder contents on explosion temperatures were studied. The results show that the Tb values first fall down and then rise with the increasing of RDX contents. A linear empiric equation, in which Tb is correlated with RDX and aluminum powder contents, was obtained. It is considered that the energies necessary to heat explosion under the test conditions are obtained from two ways, I. E. From thermal decomposition for energetic materials and from heating medium. The former is related to energetic reactant content, while the later is related to the heat conduction of the system. is proposed that the thermal conductivity of RDX-based aluminized explosives is related to aluminum powder content. Based on above view,a linear relation, which is in agreement with experiment results and can represent the correlation of Tb with RDX and aluminum powder contents,is educed in theory.%通过热爆发延滞期试验测定了含铝炸药的5s延滞期热爆发温度Tb,研究了RDX和铝粉含量对热爆发温度的影响.结果表明,随着RDX含量的增加,Tb先下降后升高,获得了描述Tb与RDX和铝粉含量关系的线性经验方程.认为在热爆发试验中体系是从含能材料热分解和加热介质两个途径获得能量(热量),前者与含能反应物的含量有关,后者与体系的热传导有关,同时认为该含铝炸药的导热系数与铝含量有关,基于这种观点,从理论上导出了符合实验结果的描述爆发温度Tb与RDX和铝粉含量关系的线性关系式.

  12. Role of black carbon electrical conductivity in mediating hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) transformation on carbon surfaces by sulfides.

    Xu, Wenqing; Pignatello, Joseph J; Mitch, William A


    Recent research has demonstrated that black carbons catalyze the transformation of a range of nitrated explosives sorbed to the carbon surfaces in the presence of sulfides. Although surface oxygenated functional groups, particularly quinones, and electrical conductivity have both been hypothesized to promote these reactions, the importance of these properties has not been tested. In this work, the importance of electrical conductivity was addressed by producing chars of increasing electrical conductivity via pyrolysis of wood shavings at increasing temperature. The reactivity of chars with respect to transformation of the explosive RDX in the presence of sulfides correlated with electrical conductivity. Oxygenated functional groups were apparently not involved, as demonstrated by the elimination of reactivity of an activated carbon after ozone treatment or sorption of model quinones to the activated carbon surface. Although RDX transformation correlated with char electrical conductivity, no RDX transformation was observed when RDX was physically separated from sulfides but electrically connected through an electrochemical cell. RDX transformation occurred in the presence of a surface-associated sulfur species. The correlation with char electrical conductivity suggests that sulfides are oxidized on carbon surfaces to products that serve as potent nucleophiles promoting RDX transformation.

  13. Biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a prospective consortium and its most effective isolate Serratia marcescens

    Young, D.M.; Ogden, K.L. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Chemical and Environmental Engineering; Unkefer, P.J. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.


    The biotransformation of hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) has been observed in liquid culture by a consortium of bacteria found in horse manure. Five types of bacteria were found to predominate in the consortium and were isolated. The most effective of these isolates at transforming RDX was Serratia marcescens. The biotransformation of RDX by all of these bacteria was found to occur only in the anoxic stationary phase. The process of bacterial growth and RDX biotransformation was quantified for the purpose of developing a predictive type model. Cell growth was assumed to follow Monod kinetics. All of the aerobic and anoxid growth parameters were determined: {mu}{sub max}, K{sub s}, and Y{sub x/s}. RDX was found to competitively inhibit cell growth in both atmospheres. Degradation of RDX by Serratia marcescens was found to proceed through the stepwise reduction of the three nitro groups to nitroso groups. Each of these reductions was found to be first order in both component and cell concentrations. The degradation rate constant for the first step in this reduction process by the consortium was 0.022 L/g cells {center_dot} h compared to 0.033 L/g cells {center_dot} h for the most efficient isolate.

  14. Mirrored continuum and molecular scale simulations of the ignition of gamma phase RDX

    Stewart, D. Scott; Chaudhuri, Santanu; Joshi, Kaushik; Lee, Kibaek


    We describe the ignition of an explosive crystal of gamma-phase RDX due to a thermal hot spot with reactive molecular dynamics (RMD), with first-principles trained, reactive force field based molecular potentials that represents an extremely complex reaction network. The RMD simulation is analyzed by sorting molecular product fragments into high and low molecular weight groups, to represent identifiable components that can be interpreted by a continuum model. A continuum model based on a Gibbs formulation has a single temperature and stress state for the mixture. The continuum simulation that mirrors the atomistic simulation allows us to study the atomistic simulation in the familiar physical chemistry framework and provides an essential, continuum/atomistic link.

  15. Studies of free field and confined explosions of aluminium enriched RDX compositions

    Trzcinski, Waldemar A.; Cudzilo, Stanislaw; Paszula, Jozef [Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)


    Research on the effect of aluminium contents and its particle size on free field and confined explosions characteristics of RDX-based compositions containing 15-60% aluminium was carried out. Parameters of blast waves produced by charges of the investigated explosives detonating in an open space were measured by the use of piezoelectric gauges. Simultaneously, photodiode set-ups were used to measure light output of the detonating charges. Quasi-static pressure measurements were conducted in steel chambers of 0.15 and 7 m{sup 3} volume filled with air. Moreover, the heat of detonation was measured with a calorimetric set in a 5.6 dm{sup 3} bomb filled with argon. The results of QSP and detonation heat measurements were compared with those obtained from thermochemical calculations. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  16. Integrated Data Collection Analysis (IDCA) Program - RDX Type II Class 5 Standard, Data Set 1

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorenson, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Moran, Jesse S. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Shelley, Timothy J. [Air Force Research Lab. (AFRL), Tyndall AFB, FL (United States); Reyes, Jose A. [Applied Research Associates, Inc., Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Whipple, Richard E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    This document describes the results of the first reference sample material—RDX Type II Class 5—examined in the proficiency study for small-scale safety and thermal (SSST) testing of explosive materials for the Integrated Data Collection Analysis (IDCA) Program. The IDCA program is conducting proficiency testing on homemade explosives (HMEs). The reference sample materials are being studied to establish the accuracy of traditional explosives safety testing for each performing laboratory. These results will be used for comparison to results from testing HMEs. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The results of the study will add SSST testing results for a broad suite of different HMEs to the literature, potentially suggest new guidelines and methods for HME testing, and possibly establish what are the needed accuracies in SSST testing to develop safe handling practices. Described here are the results for impact, friction, electrostatic discharge, and scanning calorimetry analysis of a reference sample of RDX Type II Class 5. The results from each participating testing laboratory are compared using identical test material and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. These results are then compared to historical data from various sources. The performers involved are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Air Force Research Laboratory/ RXQL (AFRL), Indian Head Division, Naval Surface Warfare Center, (IHD-NSWC), and Sandia National Laboratories (SNL). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to understand how to compare results when test protocols are not identical.

  17. Uptake, bioaccumulation, and biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its reduced metabolites (MNX and TNX) by the earthworm (Eisenia fetida).

    Zhang, Baohong; Pan, Xiaoping; Cobb, George P; Anderson, Todd A


    Uptake and accumulation kinetics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its two major N-nitroso metabolites, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), in earthworms was investigated. Results indicated that RDX and its N-nitroso metabolites were rapidly absorbed into earthworms (Eisenia fetida), reaching the highest concentrations within a few days. Accumulation of RDX was greater than its N-nitroso metabolites, as evidenced by a higher bioconcentration factor (BCF); BCFs were 1.86, 0.39, and 0.05 for RDX, MNX, and TNX, respectively. RDX and its N-nitroso metabolites were also rapidly eliminated from the earthworm and/or transformed to other metabolites, as evidenced by the rapid decrease of test compounds in earthworms after reaching their highest concentrations. The uptake of MNX and TNX increased as exposure concentration increased. Although these earthworms might (anaerobically) degrade RDX to MNX and MNX to TNX, it is hypothesized that this process would be slow. Other biotransformation pathways may be involved in biodegradation of RDX and its N-nitroso metabolites due to the fact that concentrations of tested compounds decreased in both soil and earthworms. It is hoped that these data can be used to refine environmental management strategies for RDX and for performing specific risk assessments of RDX and its N-nitroso metabolites.

  18. 燃烧稳定剂对RDX-CMDB推进剂热分解特性的影响%Influence of Combustion Stabilizers on the Thermal Decomposition Characteristics of RDX-CMDB Propellant

    陈雪莉; 王瑛; 张佩; 程丽萍; 李猛; 张丽涵


    用高压DSC和Ⅱ型钨铼微热电偶实验研究了5种燃烧稳定剂(Al2O3、ZrB2、ZrO2、SiC、WC)对RDX-CMDB推进剂的热分解特性及燃烧波温度分布的影响.结果表明,随着压力的升高,RDX-CMDB推进剂的两个特征分解峰温降低,分解热增加.相同压力下,5种燃烧稳定剂对两个特征峰温的影响不大,但对分解热影响显著,其影响程度为ZrO2和WC最大(甚至能将5MPa下的分解热提高28%以上),Al2O3次之,ZrB2、SiC最小;不同燃烧稳定剂对RDX-CMDB推进剂燃烧的作用区间不同,ZrO2和WC主要作用于固相反应区及嘶嘶区,Al2O3则作用于气相区,使作用区域的放热量及温度梯度明显提高.%The effects of five combustion stabilizers including Al2O3, ZrB2 , ZrO , SiC and WC on the thermal decomposition characteristics and the combustion wave temperatures of RDX-CMDB propellant were studied by PDSC and Ⅱ mode miniature W/Rt thermocouples. The results show that as pressure increasing, the two decomposition peak temperatures in RDX-CMDB propellant decrease and the decomposition heat increases. Under the same pressure, the influence of the five combustion stabilizers on the two decomposition peak temperatures is inconspicuous, and the influence on the decomposition heal is obvious. The influence of ZrO2 and WC is the most obviously, and the decomposition heat can be enhanced more than 28 percent at the pressure of 5 MPa. The influence of Al2O3 is slightly apparent and the influence of ZrB2 and SiC is unapparent. The combustion positions of the five combustion stabilizers acting on the RDX-CMDB propellant are different. The ZrO2 and WC stabilizers mainly act on the condense phase reaction zone and fizz zone of RDX-CMDB propellant, while the Al2O3 stabilizer acts on the gas phase zone of RDX-CMDB propellants.

  19. RDX-CMDB推进剂的催化热分解及其与燃速的相关性%Catalytic Decomposition of RDX-CMDB and its Correlation With Burning Rate

    刘子如; 刘艳; 赵凤起; 张腊莹; 衡淑云



  20. 含咪唑类铅盐催化剂的RDX-CMDB推进剂燃烧性能%Combustion Performances of RDX-CMDB Propellant with Imidazoles Lead Salt Catalyst

    张超; 杨立波; 陈俊波; 袁志锋


    研究了咪唑类含能铅盐(E-Pb)催化剂含量及与炭黑复配时对RDX-CMDB推进剂的燃速、压强指数及燃烧火焰结构等燃烧性能的影响.分析了含能催化剂和惰性催化剂影响RDX-CMDB推进剂燃烧行为的原因.结果表明,含有含能催化剂的RDX-CMDB推进剂的燃烧性能优于含惰性催化剂的RDX-CMDB推进剂的燃烧性能.10 MPa下的燃速由不含催化剂的推进剂的11.74 mm· s-1提高至含E-Pb的推进剂的25.36 mm·s-1,且随E-Pb含量的增加该推进剂的燃速增加.当含能铅盐与炭黑复配时催化效果更佳,炭黑与含能铅盐质量比为1.5∶0.25时,在4~17 MPa较宽区间出现平台燃烧,压强指数n<0.25.表明,含能铅盐对推进剂的燃烧火焰结构、暗区厚度、燃面上的亮点数目等的影响有一定规律性.

  1. Application of {sup 13}C and {sup 15}N stable isotope probing to characterize RDX degrading microbial communities under different electron-accepting conditions

    Cho, Kun-Ching; Lee, Do Gyun [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States); Fuller, Mark E.; Hatzinger, Paul B.; Condee, Charles W. [CB& I Federal Services, Lawrenceville, NJ (United States); Chu, Kung-Hui, E-mail: [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States)


    Highlights: • SIP characterized RDX-degrading communities under different e-accepting conditions. • Dominant RDX degradation pathways differed under different e-accepting conditions. • More complete detoxification of RDX occurred under methanogenic and sulfate-reducing conditions than under manganese(IV) and iron(III)-reducing conditions. - Abstract: This study identified microorganisms capable of using the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) or its metabolites as carbon and/or nitrogen sources under different electron-accepting conditions using {sup 13}C and {sup 15}N stable isotope probing (SIP). Mesocosms were constructed using groundwater and aquifer solids from an RDX-contaminated aquifer. The mesocosms received succinate as a carbon source and one of four electron acceptors (nitrate, manganese(IV), iron(III), or sulfate) or no additional electron acceptor (to stimulate methanogenesis). When RDX degradation was observed, subsamples from each mesocosm were removed and amended with {sup 13}C{sub 3}- or ring-{sup 15}N{sub 3}-, nitro-{sup 15}N{sub 3}-, or fully-labeled {sup 15}N{sub 6}-RDX, followed by additional incubation and isolation of labeled nucleic acids. A total of fifteen 16S rRNA sequences, clustering in α- and γ-Proteobacteria, Clostridia, and Actinobacteria, were detected in the {sup 13}C-DNA fractions. A total of twenty seven sequences were derived from different {sup 15}N-DNA fractions, with the sequences clustered in α- and γ-Proteobacteria, and Clostridia. Interestingly, sequences identified as Desulfosporosinus sp. (in the Clostridia) were not only observed to incorporate the labeled {sup 13}C or {sup 15}N from labeled RDX, but also were detected under each of the different electron-accepting conditions. The data suggest that {sup 13}C- and {sup 15}N-SIP can be used to characterize microbial communities involved in RDX biodegradation, and that the dominant pathway of RDX biodegradation may differ under different

  2. Al-RDX-CMDB推进剂燃烧催化机理和模型的研究%Study of Mechanism and Model for Catalyzed Combustion of Al-RDX-CMDB Propellant

    宋洪昌; 王祎; 白华萍



  3. The longstanding challenge of the nanocrystallization of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX

    Florent Pessina


    Full Text Available Research efforts for realizing safer and higher performance energetic materials are continuing unabated all over the globe. While the thermites – pyrotechnic compositions of an oxide and a metal – have been finely tailored thanks to progress in other sectors, organic high explosives are still stagnating. The most symptomatic example is the longstanding challenge of the nanocrystallization of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX. Recent advances in crystallization processes and milling technology mark the beginning of a new area which will hopefully lead the pyroelectric industry to finally embrace nanotechnology. This work reviews the previous and current techniques used to crystallize RDX at a submicrometer scale or smaller. Several key points are highlighted then discussed, such as the smallest particle size and its morphology, and the scale-up capacity and the versatility of the process.

  4. Lateral Transfer of Genes for Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) Degradation▿ †

    Andeer, Peter F.; Stahl, David A.; Bruce, Neil C.; Strand, Stuart E.


    Recent studies demonstrated that degradation of the military explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by species of Rhodococcus, Gordonia, and Williamsia is mediated by a novel cytochrome P450 with a fused flavodoxin reductase domain (XplA) in conjunction with a flavodoxin reductase (XplB). Pulse field gel analysis was used to localize xplA to extrachromosomal elements in a Rhodococcus sp. and distantly related Microbacterium sp. strain MA1. Comparison of Rhodococcus rhodochrous 11Y and Microbacterium plasmid sequences in the vicinity of xplB and xplA showed near identity (6,710 of 6,721 bp). Sequencing of the associated 52.2-kb region of the Microbacterium plasmid pMA1 revealed flanking insertion sequence elements and additional genes implicated in RDX uptake and degradation. PMID:19270122

  5. The longstanding challenge of the nanocrystallization of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)

    Spitzer, Denis


    Research efforts for realizing safer and higher performance energetic materials are continuing unabated all over the globe. While the thermites – pyrotechnic compositions of an oxide and a metal – have been finely tailored thanks to progress in other sectors, organic high explosives are still stagnating. The most symptomatic example is the longstanding challenge of the nanocrystallization of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). Recent advances in crystallization processes and milling technology mark the beginning of a new area which will hopefully lead the pyroelectric industry to finally embrace nanotechnology. This work reviews the previous and current techniques used to crystallize RDX at a submicrometer scale or smaller. Several key points are highlighted then discussed, such as the smallest particle size and its morphology, and the scale-up capacity and the versatility of the process. PMID:28326236

  6. Biodegradation of RDX and MNX with Rhodococcus sp. Strain DN22: New Insights into the Degradation Pathway


    ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 44, NO. 24, 2010 10.1021/es1023724  2010 American Chemical Society Published on Web 11/24/2010 Report...exclusively; how- FIGURE 1. Time course of aerobic biodegradation of RDX with Rhodococcus sp. DN22 VOL. 44, NO. 24, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9...water (H216O) (C) or H218O (D). 9332 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 44, NO. 24, 2010 Degradation of MNX with Rhodococcus sp. strain

  7. Calculation of the vibrational spectra of RDX as a function of pressure using the Grimme DFT potential

    Perger, Warren; Flurchick, K. M.; Slough, Wil; Valenzano, Loredana


    The density-functional theory (DFT) potential by Grimme has been proposed for describing long-range dispersion corrections. This potential has been implemented into the CRYSTAL09 program and used to calculate the vibrational spectra in RDX at equilibrium and as a function of pressure. The intensities, Born charge tensor, and high-frequency dielectric constant are reported and compared with prior theory and experiment where possible. Supported by ONR-MURI grant N00014-06-1-0459.

  8. The minimum detection limits of RDX and TNT deposited on various surfaces as determined by ion mobility spectroscopy

    Rodacy, P.


    An Ion Mobility Spectrometer (IMS) was used to determine the detection limits of RDX and TNT on six different substrates. The preparation of the explosive deposits on the surfaces is examined as well as effects due to the size, uniformity, method of application, and time that a deposit has been on a surface. Sampling methods are discussed along with effects of the surface topology. The transfer of explosives from a hand to a surface, and methods to reduce the detection limits are presented.

  9. Quantifying the degradation of TNT and RDX in a saline environment with and without UV-exposure.

    Sisco, Edward; Najarro, Marcela; Bridge, Candice; Aranda, Roman


    Terrorist attacks in a maritime setting, such as the bombing of the USS Cole in 2000, or the detection of underwater mines, require the development of proper protocols to collect and analyse explosive material from a marine environment. In addition to proper analysis of the explosive material, protocols must also consider the exposure of the material to potentially deleterious elements, such as UV light and salinity, time spent in the environment, and time between storage and analysis. To understand how traditional explosives would be affected by such conditions, saline solutions of explosives were exposed to natural and artificial sunlight. Degradation of the explosives over time was then quantified using negative chemical ionization gas chromatography mass spectrometry (GC/NCI-MS). Two explosives, trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX), were exposed to different aqueous environments and light exposures with salinities ranging from freshwater to twice the salinity of ocean water. Solutions were then aged for up to 6 months to simulate different conditions the explosives may be recovered from. Salinity was found to have a negligible impact on the degradation of both RDX and TNT. RDX was stable in solutions of all salinities while TNT solutions degraded regardless of salinity. Solutions of varying salinities were also exposed to UV light, where accelerated degradation was seen for both explosives. Potential degradation products of TNT were identified using electrospray ionization mass spectrometry (ESI-MS), and correspond to proposed degradation products discussed in previously published works [1].

  10. AI-RDX-CMDB推进剂燃烧催化机理和模型的研究

    宋洪昌; 王祎; 白华萍



  11. Shock Simulations of Single-Site Coarse-Grain RDX using the Dissipative Particle Dynamics Method with Reactivity

    Sellers, Michael; Lisal, Martin; Schweigert, Igor; Larentzos, James; Brennan, John


    In discrete particle simulations, when an atomistic model is coarse-grained, a trade-off is made: a boost in computational speed for a reduction in accuracy. Dissipative Particle Dynamics (DPD) methods help to recover accuracy in viscous and thermal properties, while giving back a small amount of computational speed. One of the most notable extensions of DPD has been the introduction of chemical reactivity, called DPD-RX. Today, pairing the current evolution of DPD-RX with a coarse-grained potential and its chemical decomposition reactions allows for the simulation of the shock behavior of energetic materials at a timescale faster than an atomistic counterpart. In 2007, Maillet et al. introduced implicit chemical reactivity in DPD through the concept of particle reactors and simulated the decomposition of liquid nitromethane. We have recently extended the DPD-RX method and have applied it to solid hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under shock conditions using a recently developed single-site coarse-grain model and a reduced RDX decomposition mechanism. A description of the methods used to simulate RDX and its tranition to hot product gases within DPD-RX will be presented. Additionally, examples of the effect of microstructure on shock behavior will be shown. Approved for public release. Distribution is unlimited.

  12. Vibrational spectra of an RDX film over an aluminum substrate from molecular dynamics simulations and density functional theory.

    Martínez de la Hoz, Julibeth M; Balbuena, Perla B


    We report calculated vibrational spectra in the range of 0-3,500 cm(-1) of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) molecules adsorbed on a model aluminum surface. A molecular film was modeled using two approaches: (1) density functional theory (DFT) was used to optimize a single RDX molecule interacting with its periodic images, and (2) a group of nine molecules extracted from the crystal structure was deposited on the surface and interacted with its periodic images via molecular dynamics (MD) simulations. In both cases, the molecule was initialized in the AAA conformer geometry having the three nitro groups in axial positions, and kept that conformation in the DFT examination, but some molecules were found to change to the AAE conformer (two nitro groups in axial and one in equatorial position) in the MD analysis. The vibrational spectra obtained from both methods are similar to each other, except in the regions where collective RDX intermolecular interactions (captured by MD simulations) are important, and compare fairly well with experimental findings.

  13. Analysis of the key intermediates of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) in groundwater: occurrence, stability and preservation.

    Paquet, Louise; Monteil-Rivera, Fanny; Hatzinger, Paul B; Fuller, Mark E; Hawari, Jalal


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a widely used explosive that is present in soils at a number of military sites, including training and testing ranges. Because of its relatively weak adsorption to soil, RDX frequently migrates through the unsaturated zone and causes groundwater contamination. In the environment, RDX can transform to produce mono-, di-, and tri-nitroso derivatives (MNX, DNX, and TNX) and the ring cleavage products methylenedinitramine (MEDINA) and 4-nitro-2,4-diazabutanal (NDAB). The present study was undertaken to analyze RDX and its products in groundwater samples taken from various US military sites. The stability of some of the common transformation intermediates of RDX, including the nitroso derivatives, NDAB and MEDINA, under typical conditions in a groundwater aquifer is not well understood, and appropriate preservation methods for these compounds have not been established. Therefore, we studied the inherent stability of these compounds in deionized water and in groundwater, and evaluated various preservation techniques, including adjustment of pH, temperature, and salinity. NDAB and nitroso derivatives were stable under typical ambient environmental conditions, but MEDINA was highly unstable. The addition of sea salts (10% w/v) was found to stabilize MEDINA when the samples were stored at 4 °C. Using appropriate preservation techniques, we detected nitroso derivatives and NDAB, but no MEDINA, at some of the sites investigated. Stabilizing RDX intermediate products in field samples to allow detection is important because the presence of any of these chemicals can indicate past contamination by RDX and provide insight into the occurrence of in situ natural attenuation.

  14. Dissolution and sorption of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) residues from detonated mineral surfaces.

    Jaramillo, Ashley M; Douglas, Thomas A; Walsh, Marianne E; Trainor, Thomas P


    Composition B (Comp B) is a commonly used military formulation composed of the toxic explosive compounds 2,4,6-trinitrotoluene (TNT), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Numerous studies of the temporal fate of explosive compounds in soils, surface water and laboratory batch reactors have been conducted. However, most of these investigations relied on the application of explosive compounds to the media via aqueous addition and thus these studies do not provide information on the real world loading of explosive residues during detonation events. To address this we investigated the dissolution and sorption of TNT and RDX from Comp B residues loaded to pure mineral phases through controlled detonation. Mineral phases included nontronite, vermiculite, biotite and Ottawa sand (quartz with minor calcite). High Performance Liquid Chromatography and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy were used to investigate the dissolution and sorption of TNT and RDX residues loaded onto the mineral surfaces. Detonation resulted in heterogeneous loading of TNT and RDX onto the mineral surfaces. Explosive compound residues dissolved rapidly (within 9 h) in all samples but maximum concentrations for TNT and RDX were not consistent over time due to precipitation from solution, sorption onto mineral surfaces, and/or chemical reactions between explosive compounds and mineral surfaces. We provide a conceptual model of the physical and chemical processes governing the fate of explosive compound residues in soil minerals controlled by sorption-desorption processes. Published by Elsevier Ltd.

  15. The essential role of nitrogen limitation in expression of xplA and degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in Gordonia sp. strain KTR9.

    Zhu, Song-Hua; Reuther, Jens; Liu, Jie; Crocker, Fiona H; Indest, Karl J; Eltis, Lindsay D; Mohn, William W


    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a widely used explosive and a major soil and groundwater contaminant. Organisms such as Gordonia sp. KTR9, capable of degrading RDX and using it as an N source, may prove useful for bioremediation of contaminated sites. XplA is a cytochrome P450 monooxygenase responsible for RDX degradation. Expression of xplA in KTR9 was not induced by RDX but was strongly induced (50-fold) during N-limited growth. When glnR, encoding a regulatory protein affecting N assimilation in diverse Actinobacteria, was deleted from KTR9, the bacterium lost the ability to use nitrate, nitrite, and RDX as N sources. Deletion of glnR also abolished the inhibition of xplA expression by nitrite. Our results confirm the essential role of GlnR in regulating assimilation of nitrite, but there was no evidence for a direct role of GlnR in regulating XplA expression. Rather, the general availability of nitrogen repressed XplA expression. We conclude that the inability of the glnR mutant to use RDX as an N source was due to its inability to assimilate nitrite, an intermediate in the assimilation of nitrogen from RDX. Regulation of XplA does not seem adaptive for KTR9, but it is important for RDX bioremediation with KTR9 or similar bacteria.

  16. Experiment and Reactive-Burn Modeling in the RDX Based Explosive XTX 8004

    Johnson, Carl; Murphy, Mike; Gustavsen, Rick; Jackson, Scott; Vincent, Samuel


    XTX 8004 consists of 80 wt. % cyclotrimethylenetrinitramine (RDX), and 20 wt. % Sylgard 182, a silicone rubber used as a binder. Nominal density is 1.5 g/cm3. Uncured XTX 8004 is putty like and can be molded or extruded. The XTX 8004 detonation product Hugoniot calibration was obtained from cylinder tests using a genetic algorithm approach to parameterize a Jones-Wilkins-Lee (JWL) equation of state. Additionally, we conducted four gas-gun experiments that were instrumented with embedded electromagnetic particle velocity gauges. These provided wave profiles to which we calibrated an Ignition and Growth reactive burn (IGRB) model in ALE3D for 1-D shock to detonation transitions. Further, acceptor and donor XTX 8004 were extruded into opposite sides of a monolithic polymethylmethacrylate (PMMA) block with a known thickness of PMMA forming the attenuator plate, the so-called monolithic gap test (MGT). Detonation and initiation in the XTX 8004 was recorded using multiple ultra-high-speed images of the position of the shock front in the PMMA. Input to the acceptor charge was estimated from stress wave profiles photographed inside the attenuator as well as with photonic Doppler velocimetry (PDV) measurements of the free surface velocity beneath the attenuator plate. Results were simulated using IGRB in ALE3D. Parameterization of IGRB to 1-D vs. 2-D experiments will be discussed.

  17. High Density, Insensitive Oxidizer With RDX Performance Final Report CRADA No. TC02178.0

    Pagoria, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Preda, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Physical Sciences, Inc. (PSI), to develop a synthesis and evaluate a novel high density, insensitive oxidizer with RDX performance. This CRADA resulted from the award of a Phase I STTR ("STTR") from DOD. In recent years, the synthesis of new energetic heterocyclic compounds to replace the energetic materials currently in the stockpile has received a great amount of attention. The Office of the Secretary of Defense has identified that there is a need to incorporate new energetic materials in current and future weapon systems in an effort to increase performance and decrease sensitivity. For many of the future weapon systems, incorporation of energetic compounds currently in the stockpile will not provide the desired performance and sensitivity goals. The success of this CRADA may lead to a Phase I option STTR from DOD and to a Phase II STTR from DOD. The goal of this CRADA was to produce and test a novel oxidizer, 2,5,8-trinitroheptazine (TNH).

  18. Integrated Data Collection Analysis (IDCA) Program - Statistical Analysis of RDX Standard Data Sets

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Phillips, Jason J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelley, Timothy J. [Air Force Research Lab. (AFRL), Tyndall AFB, FL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The Integrated Data Collection Analysis (IDCA) program is conducting a Proficiency Test for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are statistical analyses of the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of the RDX Type II Class 5 standard. The material was tested as a well-characterized standard several times during the proficiency study to assess differences among participants and the range of results that may arise for well-behaved explosive materials. The analyses show that there are detectable differences among the results from IDCA participants. While these differences are statistically significant, most of them can be disregarded 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 for 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 the broader safety testing community based on the range of methods, instruments, and environments included in the IDCA Proficiency Test.

  19. Fate and transport of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its degradation products in sedimentary and volcanic rocks, Los Alamos, New Mexico.

    Heerspink, Brent Porter; Pandey, Sachin; Boukhalfa, Hakim; Ware, Doug S; Marina, Oana; Perkins, George; Vesselinov, Velimir V; WoldeGabriel, Giday


    High-explosive compounds including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were used extensively in weapons research and testing at Los Alamos National Laboratory (LANL). Liquid effluents containing RDX were released to an outfall pond that flowed to Cañon de Valle at LANL's Technical Area 16 (TA-16), resulting in the contamination of the alluvial, intermediate and regional groundwater bodies. Monitoring of groundwater within Cañon de Valle has shown persistent RDX in the intermediate perched zone located between 225 and 311 m below ground surface. Monitoring data also show detectable levels of RDX putative anaerobic degradation products. Batch and column experiments were conducted to determine the extent of adsorption-desorption and transport of RDX and its degradation products (MNX, DNX, and TNX) in major rock types that are within the RDX plume. All experiments were performed in the dark using water obtained from a well located at the center of the plume, which is fairly oxic and has a neutral pH of 7.5. Retardation factors and partitioning coefficient (Kd) values for RDX were calculated from batch experiments. Additionally, retardation factors and Kd values for RDX and its degradation products were calibrated from column experiments using a one-dimensional transport model with equilibrium sorption (linear isotherm). Results from the column and batch experiments showed little to no sorption of RDX to the aquifer materials tested, with retardation factors ranging from 1.0 to 1.8 and Kd values varying from 0 to 0.70 L/kg. Results also showed no measurable differences between the transport properties of RDX and its degradation products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Use of an algD promoter-driven expression system for the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Pseudomonas sp. HK-6.

    Lee, Bheong-Uk; Baek, Hyun; Oh, Kye-Heon


    Pseudomonas sp. HK-6 is able to utilize hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as a sole nitrogen source. The HK-6 strain was stimulated to produce an exopolymer, mainly alginate, as a stress response when grown in LB broth containing RDX, synthesizing ~230 μg/mL after 48 h. The algA mRNA levels in HK-6 increased by 7-8-fold after 2-6 h of exposure to 0.1 mM RDX, as measured by RT-qPCR. HK-6 was able to degrade ~25 % of 0.1 mM RDX after 20 days and 60 % after 50 days, whereas the pnrB null mutant only degraded less than 1 % after 50 days. The introduction of an algD promoter-pnrB gene fusion into the pnrB mutant fully restored RDX-degradation capability. To facilitate a study of PnrB action on RDX, a His6-PnrB fusion protein was heterologously expressed in E. coli BL21 cells, and the enzymatic activity on RDX was assayed by measuring the decrease in absorbance at 340 nm due to NADH oxidation. At the fixed condition of 0.1 mM RDX, 0.2 mM NADH, and 1 μg His6-PnrB, the absorbance at 340 nM gradually decreased and reached to its minimum value after 30 min. However, calculating the V max and K m values of PnrB for RDX was challenging due to extremely low solubility of RDX in water. The results clearly indicate the potential use of the algD promoter in studies of some genes in Pseudomonas species.

  1. Microbial community characterization and functional gene quantification in RDX-degrading microcosms derived from sediment and groundwater at two naval sites.

    Wilson, Fernanda Paes; Cupples, Alison M


    The explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has long been recognized as a problematic environmental pollutant, and efforts to remediate contaminated soils, sediments, and groundwater have been going on for decades. In recent years, much interest has focused on using bioremediation to clean up these sites. The current study investigated the microorganisms (16S rRNA genes, Illumina) and functional genes (xenA, xenB, and xplA) linked to RDX biodegradation in microcosms composed of sediment or groundwater from two Navy sites. For this, experiments included sediment samples from three depths (5 to 30 ft) from two wells located in one Navy site. In addition, the groundwater upstream and downstream of an emulsified oil biobarrier was examined from another Navy site. Further, for the groundwater experiments, the effect of glucose addition was explored. For the sediment experiments, the most enriched phylotypes during RDX degradation varied over time, by depth and well locations. However, several trends were noted, including the enrichment of Pseudomonas, Rhodococcus, Arthrobacter, and Sporolactobacillus in the sediment microcosms. For the groundwater-based experiments, Pseudomonas, unclassified Rhodocyclaceae, Sphingomonas, and Rhodococcus were also highly abundant during RDX degradation. The abundance of both xplA and xenA significantly increased during RDX degradation compared to the control microcosms for many treatments (both groundwater and sediment microcosms). In a limited number of microcosms, the copy number of the xenB gene increased. Phylotype data were correlated with functional gene data to highlight potentially important biomarkers for RDX biodegradation at these two Navy sites.

  2. Genome Shuffling of Stenotrophomonas maltophilia OK-5 for Improving the Degradation of Explosive RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine).

    Lee, Bheong-Uk; Choi, Moon-Seop; Kim, Dong-Min; Oh, Kye-Heon


    A genome-shuffled Stenotrophomonas maltophilia strain showing the enhanced ability of RDX degradation was constructed, and its characteristics were compared with those of the wild-type one. The shuffled strain was able to completely degrade 25, 50, and 75 µM RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) within 10, 30, and 50 days, respectively. However, it took 30 and 70 days for the wild-type strain to degrade 25 and 50 µM RDX, respectively, and at day 70, the strain degraded only 67% of 75 µM RDX. The shuffled strain reached its maximum growth at 50-60 days and exhibited approximately 1.5-fold increased cell numbers. SEM revealed more severe damage on the surface of the wild-type cells compared to the genome-shuffled cells. The mRNA levels of dnaK and groEL encoding the heat shock proteins were increased by 2.5-fold and fourfold, and DnaK and GroEL proteins were more highly produced in the shuffled cells. In addition, the mRNA levels of pnrB encoding a TNT nitroreductase, and algA involved in exopolymer biosynthesis, were slightly higher in the shuffled strain, but not as high as those of dnaK and groEL. These results indicate that the genome shuffling rendered the shuffled cells more resistant to RDX stress. A proteomic comparison revealed changes in the production levels of certain proteins including nitrate and cell protection, particularly those involved in metabolism. These proteomic analyses provide clues for understanding the improved RDX degradation by the genome-shuffled S. maltophilia strain.

  3. In Vitro Study of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) Metabolism in Human Liver


    Casarett & Doull ’s Toxicology: The Basic Science of Poisons (2001) by Curtis D. Klaassen 6111 Edition, Chapter 13, The McGraw-Hill Companies, lnc. e. Lev...Rhodococcus sp. Strain DN22, Applied and Environ. Micro. 69(3): 1347-51. c. Helena M. B. Seth-Smith (2002): MICROBIAL DEGRADATION OF RDX, Ph.D. thesis...Li of In Vitro ADMET Laboratories, LLC, Rockville, MD )> Dr. David Kwok of Biopharmaceutical Research Inc, Canada )> Oliver Curtis and Michael Hable of Directorate of Laboratory Sciences, US Army CHPPM 17

  4. Simulating thermal explosion of RDX-based explosives: Model comparison with experiment

    Yoh, J J; McClelland, M A; Maienschein, J L; Wardell, J F; Tarver, C M


    We compare two-dimensional model results with measurements for the thermal, chemical and mechanical behavior in a thermal explosion experiment. Confined high explosives are heated at a rate of 1 C per hour until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydro time scale. During the pre-ignition phase, quasi-static mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydro dynamic calculation is performed as a burn front propagates through the HE. Two RDX-based explosives, C-4 and PBXN-109, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in large scale thermal explosion tests. The explosion temperatures for both HE's are predicted to within 5 C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase. During the heating phase, simulated wall strains provide only an approximate representation of measured values indicating a better numerical treatment is needed to provide accurate results. The results also show that more numerical accuracy is needed for vessels with lesser confinement strength. For PBXN-109, the measured wall strains during the explosion are well represented by the ALE3D calculations.

  5. 偶氮四唑胍对含催化剂的RDX-CMDB推进剂燃烧性能的影响研究%Study on the influences of guanidinium azotetrazolate on combustion characteristics of RDX-CMDB propellants containing catalysts

    蔚红建; 王琼; 陈春林


    采用浇注工艺制备了GZT部分取代RDX的系列含催化剂的RDX-CMDB推进剂样品.研究了GZT对含催化剂的RDX-CMDB推进剂的燃速、压强指数及燃烧火焰结构等燃烧性能的影响,对比分析了GZT对含催化剂和不舍催化剂的RDX-CMDB推进剂燃烧行为影响不同的原因,并采用DSC实验初步研究了含GZT和催化剂的RDX-CMDB推进剂的热行为.结果发现,GZT对推进剂的火焰温度、火焰的暗区厚度、燃面上的亮点数目、燃烧表面对凝聚相的温度梯度等都呈现一定规律性的影响;在1~10 MPa内,GZT使含催化剂的RDX-CMDB推进剂燃速降低,压强指数升高;热行为研究表明,含催化剂的GZT-RDX-CMDB推进剂的DSC曲线上出现了GZT单独分解峰,且DSC的第一分解峰温随GZT的加入而减小.%Samples of RDX-CMDB propellents containing catalysts with RDX replaced by guanidinium azotetrazolate ( GZT) were prepared using slurry casting technique. The influences of GZT on combustion behaviors of RDX-CMDB propellants including burning rates, pressure exponents and flame structure were studied, and the reasons for the difference of combustion behaviors between propellants with catalysts and without catalysts were analyzed. The thermal behaviors of propellants were analyzed through the difference scanning calorimeter( DSC). Results indicate that GZT has great effects on flame temperature, width of dark zone, numbers of lighting point on the combustion surfaces and temperature gradient of combustion surface to condensed phase. The burning rates of propellants decrease with the increase in GZT content under pressure ranging from 1 Mpa to 10 Mpa,while pressure exponents increase. In the DSC curve of propellants containing GZT and catalysts, a new independent decomposition peak corresponding to decomposition of GZT appears, and the first decomposition peak temperature decreases with addition of GZT into propellant.

  6. A theoretical study of the relaxation of a phenyl group chemisorbed to an RDX freestanding thin film

    Pereverzev, Andrey; Sewell, Thomas D.


    Energy relaxation from an excited phenyl group chemisorbed to the surface of a crystalline thin film of α-1,3,5-trinitro-1,3,5-triazacyclohexane (α-RDX) at 298 K and 1 atm is simulated using molecular dynamics. Two schemes are used to excite the phenyl group. In the first scheme, the excitation energy is added instantaneously as kinetic energy by rescaling momenta of the 11 atoms in the phenyl group. In the second scheme, the phenyl group is equilibrated at a higher temperature in the presence of static RDX geometries representative of the 298 K thin film. An analytical model based on ballistic phonon transport that requires only the harmonic part of the total Hamiltonian and includes no adjustable parameters is shown to predict, essentially quantitatively, the short-time dynamics of the kinetic energy relaxation (˜200 fs). The dynamics of the phenyl group for times longer than about 6 ps follows exponential decay and agrees qualitatively with the dynamics described by a master equation. Long-time heat propagation within the bulk of the crystal film is consistent with the heat equation.

  7. The stability of TNT, RDX and PETN in simulated post-explosion soils: Implications of sample preparation for analysis.

    Yu, H A; DeTata, D A; Lewis, S W; Nic Daeid, N


    Explosives residues in soils may be a useful source of evidence following the detonation of an improvised explosive device (IED), such as a vehicle-borne IED. Soil samples collected from the vicinity of an explosion scene will often be stored for some time prior to analysis, yet explosives residues in soil samples are susceptible to rapid degradation or transformation. Although some research has assessed the use of different storage temperatures with a view to reducing explosives' degradation over time, further research examining the degradation of explosives in soil when stored under a variety of storage conditions is crucial to determine the optimal sample collection and storage procedures for soil containing explosives residues. In this work, three different soils were spiked with solutions of TNT, RDX and PETN and stored either at room temperature, refrigerated or frozen. Samples were extracted over 6 weeks, with additional samples gamma-irradiated or nitrogen purged prior to storage. Experimental results indicate that TNT underwent very rapid degradation at room temperature, attributed to microbial action, whereas PETN and RDX proved to be more stable. Gamma irradiation and nitrogen purging proved of some benefit for mitigating TNT degradation, with lower storage temperatures ultimately proving the most effective method of mitigating degradation. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Influence of molecular structure on the laser-induced plasma emission of the explosive RDX and organic polymers.

    De Lucia, Frank C; Gottfried, Jennifer L


    A series of organic polymers and the military explosive cyclotrimethylenetrinitramine (RDX) were studied using the light emission from a femtosecond laser-induced plasma under an argon atmosphere. The relationship between the molecular structure and plasma emission was established by using the percentages of the atomic species (C, H, N, O) and bond types (C-C, C═C, C-N, and C≡N) in combination with the atomic/molecular emission intensities and decay rates. In contrast to previous studies of organic explosives in which C2 was primarily formed by recombination, for the organic materials in this study the percentage of C-C (and C═C) bonds was strongly correlated to the molecular C2 emission. Time-resolved emission spectra were collected to determine the lifetimes of the atomic and molecular species in the plasma. Observed differences in decay rates were attributed to the differences in both the molecular structure of the organic polymers or RDX and the chemical reactions that occur within the plasma. These differences could potentially be exploited to improve the discrimination of explosive residues on organic substrates with laser-induced breakdown spectroscopy.

  9. Synthesis of Waterborne Polyurethane Modiifed by Nano-SiO2 Silicone and Properties of the WPU Coated RDX

    Li Yang; Zhao Tianbo; Qu Xiaoling; Ding Hongjing; Li Fengyan


    A series of nano silica/silicone modiifed waterborne polyurethane (WPU) have been synthesized from polytet-ramethylene glycol and isophorone diisocyanate, dihydroxymethyl propionic acid and triethylamine, ethylenediamine, trimethylolpropane, nano-SiO2 and the silane coupling agent KH550. The effect of the dosage of nano-SiO2 on the WPU-Si membrane and the coated RDX (cyclotrimethylenetrinitramine) particles have been studied in terms of their surface prop-erties, mechanical properties, and thermal stability. The results showed that with the increase of Si content, the stability of the emulsion reduced gradually. The material with more Si content displayed an increased thermodynamic stability, an increased high temperature resistance, an increased tensile strength and a decreased elongation at break. With the increase of Si content, the surface tension of the material decreased, the bibulous rate reduced, and the contact angle increased gradually, so that the surface tension of the polyurethane and RDX are close to each other which could improve the performance of coating.

  10. Characterization and proteomic analysis of the Pseudomonas sp. HK-6 xenB knockout mutant under RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) stress.

    Lee, Bheong-Uk; Choi, Moon-Seop; Oh, Kye-Heon


    Pseudomonas sp. HK-6 is able to utilize RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) as its sole nitrogen source. The role of the xenB gene, encoding xenobiotic reductase B, was investigated using HK-6 xenB knockout mutants. The xenB mutant degraded RDX to a level that was 10-fold less than that obtained with the wild-type HK-6 strain. After 60 days of culture with 25 or 50 μM RDX, no residual RDX was detected in the supernatants of the wild-type aerobically grown cultures, whereas approximately 90 % of the RDX remained in the xenB mutant cultures. The xenB mutant bacteria exhibited a 10(2)-10(4)-fold decrease in survival rate compared to the wild-type. The expression of DnaK and GroEL proteins, two typical stress shock proteins (SSPs), in the xenB mutant increased after immediate exposure to RDX, yet dramatically decreased after 4 h of exposure. In addition, DnaK and GroEL were more highly expressed in the cultures with 25 μM RDX in the medium but showed low expression in the cultures with 50 or 75 μM RDX. The expression levels of the dnaK and groEL genes measured by RT-qPCR were also much lower in the xenB genetic background. Analyses of the proteomes of the HK-6 and xenB mutant cells grown under conditions of RDX stress showed increased induction of several proteins, such as Alg8, alginate biosynthesis sensor histidine kinase, and OprH in the xenB mutants when compared to wild-type. However, many proteins, including two SSPs (DnaK and GroEL) and proteins involved in metabolism, exhibited lower expression levels in the xenB mutant than in the wild-type HK-6 strain. The xenB knockout mutation leads to reduced RDX degradation ability, which renders the mutant more sensitive to RDX stress and results in a lower survival rate and an altered proteomic profile under RDX stress.


    Phytoremediation is currently being explored for its potential to clean-up of the large number of military sites that have been contaminated by explosives such as 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Although some of the enzymes responsi...

  12. Release of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) from polymer-bonded explosives (PBXN-109) into water by artificial weathering.

    Kumar, M; Ladyman, M K; Mai, N; Temple, T; Coulon, F


    Polymer-bonded explosives (PBX) fulfil the need for insensitive munitions. However, the environmental impacts of PBX are unclear, even though it is likely that PBX residues from low-order detonations and unexploded ordnance are deposited on military training ranges. The release of high explosives from the polymer matrix into the environment has not been studied in detail, although as polymers degrade slowly in the environment we anticipate high explosives to be released into the environment. In this study, PBXN-109 (nominally 64% RDX) samples were exposed to variable UK climatic conditions reproduced in the laboratory to determine the effects of temperature, UV irradiation and rainfall on the release of RDX from the polymer binder. The most extreme conditions for spring, summer and winter in the UK were artificially reproduced. We found that up to 0.03% of RDX was consistently released from PBXN-109. The rate of RDX release was highest in samples exposed to the summer simulation, which had the lowest rainfall, but the highest temperatures and longest UV exposure. This was confirmed by additional experiments simulating an extreme summer month with consistently high temperatures and long periods of sunlight. These results probably reflect the combination of polymer swelling and degradation when samples are exposed to higher temperatures and prolonged UV irradiation. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.


    Phytoremediation is currently being explored for its potential to clean-up of the large number of military sites that have been contaminated by explosives such as 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Although some of the enzymes responsi...

  14. In silico kinetics of alkaline hydrolysis of 1,3,5-trinitro-1,3,5-triazinane (RDX): M06-2X investigation.

    Sviatenko, L K; Gorb, L; Leszczynska, D; Okovytyy, S I; Shukla, M K; Leszczynski, J


    Alkaline hydrolysis of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), as one of the most promising methods for nitrocompound remediation, was investigated computationally at the PCM(Pauling)/M06-2X/6-311++G(d,p) level of theory. Computational simulation shows that RDX hydrolysis is a highly exothermic multistep process involving initial deprotonation and nitrite elimination, cycle cleavage, further transformation of cycle-opened intermediates to end products caused by a series of C-N bond ruptures, hydroxide attachments, and proton transfers. Computationally predicted products of RDX hydrolysis such as nitrite, nitrous oxide, formaldehyde, formate, and ammonia correspond to experimentally observed ones. Accounting of specific hydration of hydroxide is critical to create an accurate kinetic model for alkaline hydrolysis. Simulated kinetics of the hydrolysis are in good agreement with available experimental data. A period of one month is necessary for 99% RDX decomposition at pH 10. Computations predict significant increases of the reaction rate of hydrolysis at pH 11, pH 12, and pH 13.

  15. Investigating differences in the ability of XplA/B-containing bacteria to degrade the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Sabir, Dana Khdr; Grosjean, Nicolas; Rylott, Elizabeth L; Bruce, Neil C


    The xenobiotic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a toxic explosive and environmental pollutant. This study examines three bacterial species that degrade RDX, using it as a sole source of nitrogen for growth. Although isolated from diverse geographical locations, the species contain near identical copies of genes encoding the RDX-metabolising cytochrome P450, XplA and accompanying reductase, XplB. Sequence analysis indicates a single evolutionary origin for xplA and xplB as part of a genomic island, which has been distributed around the world via horizontal gene transfer. Despite the fact that xplA and xplB are highly conserved between species, Gordonia sp. KTR9 and Microbacterium sp. MA1 degrade RDX more slowly than Rhodococcus rhodochrous 11Y. Both Gordonia sp. KTR9 and Microbacterium sp. MA1 were found to contain single base-pair mutations in xplB which, following expression and purification, were found to encode inactive XplB protein. Additionally, the Gordonia sp. KTR9 XplB was fused to glutamine synthetase, which would be likely to sterically inhibit XplB activity. Although the glutamine synthetase is fused to XplB and truncated by 71 residues, it was found to be active. Glutamine synthetase has been implicated in the regulation of nitrogen levels; controlling nitrogen availability will be important for effective bioremediation of RDX. © FEMS 2017. All rights reserved. For permissions, please e-mail:

  16. Effect of 2,4-Dihydroxybenzoate Lead/Cupric on Combustion Properties of Al/RDX-CMDB Propellants%2,4-二羟基苯甲酸铅铜盐对Al/RDX-CMDB推进剂燃烧性能的影响

    袁志锋; 赵凤起; 焦建设; 张教强; 杨立波; 郑晓东; 张超; 谢波


    为了研究2,4-二羟基苯甲酸铅铜盐(Pb/Cu-SDHB)单独或与其它催化剂复合后对含Al粉和黑索今(RDX)改性双基(Al/RDX-CMDB)推进剂燃烧性能的影响,采用吸收-压延方法制备了推进剂样品,用靶线法测试了推进剂燃速。结果表明:Pb/Cu-SDHB能有效调节推进剂燃烧性能,显著提高了Al/RDX-CMDB推进剂的燃速,并明显降低了压强指数;3.0%Pb/Cu-SDHB与0.65%炭黑复合后使Al/RDX-CMDB推进剂在10~15MPa的压强指数降低至-0.1,10MPa下燃速超过20mm/s。%In order to investigate the effects of lead/cupric salt of 2,4-dihydroxybenzoate(Pb/Cu-SDHB)itself, or composite with other catalysts on the combustion properties of Al/RDX-CMDB propellant, the propellant samples were prepared through a solventless extrusion technique, as well as the burning rate of propellants were measured by stand burner method .The results showed that Pb/Cu-SDHB could increase the burning rate and reduce the pressure exponent of Al/RDX-CMDB propellant notably. When 3.0%Pb/Cu-SDHB composited with 0.65%carbon, the pressure exponent of Al/RDX-CMDB propellant reduced to-0.1 under 10~15MPa, and the burning rate at 10MPa would exceed 20mm/s.

  17. Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

    Miller, C. J.; Yoder, T. S.


    Explosive trace detection equipment has been deployed to airports for more than a decade. During this time, the need for standardized procedures and calibrated trace amounts for ensuring that the systems are operating properly and detecting the correct explosive has been apparent but a standard representative of a fingerprint has been elusive. Standards are also necessary to evaluate instrumentation in the laboratories during development and prior to deployment to determine sample throughput, probability of detection, false positive/negative rates, ease of use by operator, mechanical and/or software problems that may be encountered, and other pertinent parameters that would result in the equipment being unusable during field operations. Since many laboratories do not have access to nor are allowed to handle explosives, the equipment is tested using techniques aimed at simulating the actual explosives fingerprint. This laboratory study focused on examining the similarities and differences in three different surface contamination techniques that are used to performance test explosive trace detection equipment in an attempt to determine how effective the techniques are at replicating actual field samples and to offer scenarios where each contamination technique is applicable. The three techniques used were dry transfer deposition of standard solutions using the Transportation Security Laboratory’s (TSL) patented dry transfer techniques (US patent 6470730), direct deposition of explosive standards onto substrates, and fingerprinting of actual explosives onto substrates. RDX was deposited on the surface of one of five substrates using one of the three different deposition techniques. The process was repeated for each substrate type using each contamination technique. The substrate types used were: 50% cotton/50% polyester as found in T-shirts, 100% cotton with a smooth surface such as that found in a cotton dress shirt, 100% cotton on a rough surface such as that

  18. The Effect of Nano-Aluminumpowder on the Characteristic of RDX based Aluminized Explosives Underwater Close-Filed Explosion

    Junting Yin


    Full Text Available In order to investigate the effect of nano-aluminum powder on the characteristic of RDX based aluminized explosives underwater closed-filed explosions, the scanning photographs along the radial of the charges were gained by a high speed scanning camera. The photographs of two different aluminized explosives underwater explosion have been analyzed, the shock wave curves and expand curves of detonation products were obtained, furthermore the change rules of shock waves propagation velocity, shock front pressure and expansion of detonation products of two aluminized explosives were investigated, and also the parameters of two aluminized explosives were contrasted. The results show that the aluminized explosive which with nano-aluminum whose initial shock waves pressure propagation velocity, shock front pressure are smaller than the aluminized explosive without nano-aluminum and has lower decrease rate attenuation of energy.

  19. Hierarchical Multiscale Framework for Materials Modeling: Advances in Scale-Bridging Applied to a Taylor Anvil Impact Test of RDX

    Barnes, Brian; Leiter, Kenneth; Becker, Richard; Knap, Jaroslaw; Brennan, John

    As part of a multiscale modeling effort, we present progress on a challenge in continuum-scale modeling: the direct incorporation of complex molecular-level processes in the constitutive evaluation. In this initial phase of the research we use a concurrent scale-bridging approach, with a hierarchical multiscale framework running in parallel to couple a particle-based model (the ''lower scale'') computing the equation of state (EOS) to the constitutive response in a finite-element multi-physics simulation (the ''upper scale''). The lower scale simulations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) use a force-matched coarse-grain model and dissipative particle dynamics methods, and the upper scale simulation is of a Taylor anvil impact experiment. Results emphasize use of adaptive sampling (via dynamic kriging) that accelerates time to solution, and its comparison to fully ''on the fly'' runs. Work towards inclusion of a fully reactive EOS is also discussed.

  20. Discrimination and identification of RDX/PETN explosives by chemometrics applied to terahertz time-domain spectral imaging

    Bou-Sleiman, J.; Perraud, J.-B.; Bousquet, B.; Guillet, J.-P.; Palka, N.; Mounaix, P.


    Detection of explosives has always been a priority for homeland security. Jointly, terahertz spectroscopy and imaging are emerging and promising candidates as contactless and safe systems. In this work, we treated data resulting from hyperspectral imaging obtained by THz-time domain spectroscopy, with chemometric tools. We found efficient identification and sorting of targeted explosives in the case of pure and mixture samples. In this aim, we applied to images Principal Component Analysis (PCA) to discriminate between RDX, PETN and mixtures of the two materials, using the absorbance as the key-parameter. Then we applied Partial Least Squares-Discriminant Analysis (PLS-DA) to each pixel of the hyperspectral images to sort the explosives into different classes. The results clearly show successful identification and categorization of the explosives under study.

  1. Negative-ion formation in the explosives RDX, PETN, and TNT by using the reversal electron attachment detection technique

    Boumsellek, S.; Alajajian, S. H.; Chutjian, A.


    First results of a beam-beam, single-collision study of negative-ion mass spectra produced by attachment of zero-energy electrons to the molecules of the explosives RDX, PETN, and TNT are presented. The technique used is reversal electron attachment detection (READ) wherein the zero-energy electrons are produced by focusing an intense electron beam into a shaped electrostatic field which reverses the trajectory of electrons. The target beam is introduced at the reversal point, and attachment occurs because the electrons have essentially zero longitudinal and radial velocity. The READ technique is used to obtain the 'signature' of molecular ion formation and/or fragmentation for each explosive. Present data are compared with results from atmospheric-pressure ionization and negative-ion chemical ionization methods.

  2. Nonisothermal Crystallization Kinetics of DNAN in RDX%DNAN在RDX中的非等温结晶动力学

    王红星; 蒋芳芳; 王浩; 罗一鸣; 高杰


    The non-isothermal crystallization of 2 ,4-Dinitroanisole (DNAN) in RDX was studies by differential scanning calorimetry. Several kinetics models were used to investigate the crystallization behavior of DNAN. The results show that RDX can reduce the super-cooling degree of DNAN and eliminate self-heating of DNAN crystallization. The crystallization kinetics exponent obtained by Avrami equation is 2.34. The mechanism function g{α) was determined. Ozawa exponent of non-isothermal crystallization (m) is 0.77 from Avrami-Ozawa equations. Activation energy ( Ea) of DNAN non-isthermal crystallization is 214.99 kj · mol-1 with Hu-Zhao-Cao-Zhao equation.%采用差示扫描量热仪研究了2,4-二硝基苯甲醚(DNAN)在RDX中的非等温结晶行为,运用多种数学模型对DNAN的结晶动力学进行数据处理.结果表明,RDX能够降低过冷度,消除自加热.由Avrami方程计算得到了DNAN结晶动力学的Avrami 指数为2.34,确定了结晶过程的机理函数g(α).由Avrami-Ozawa方程获得了Ozawa指数为0.77.由Hu-Zhao-Gao-Zhao方程获得了结晶动力学参数活化能为214.99 kJ·mol-1.

  3. Effects of Organic Copper Salts on Combustion Characteristics and Thermal Decomposition at High Pressure of RDX-CMDB Propellants%有机铜盐对RDX-CMDB推进剂的燃烧性能和高压热分解的影响

    付小龙; 李吉祯; 樊学忠; 王琼; 蔚红建; 张腊莹


    研究了三种有机铜盐燃烧催化剂β-雷索辛酸铜(β-Cu)、3-硝基-1,2,4三唑-5-酮铜盐(NTO-Cu)和2,4-二硝基咪唑铜(NI-Cu)对RDX-CMDB推进剂不同压强下的燃烧性能和热分解的影响.结果表明,三种有机铜盐燃烧催化剂对RDX-CMDB推进剂的燃烧性能和差示扫描量热法(DSC)特征量有一定影响; β-Cu、NTO-Cu和NI-Cu三种有机铜盐可使RDX-CMDB推进剂热分解的第一个分解峰温Tp1提前1~4 ℃,并将第二个分解峰温Tp2提前5~11 ℃; RDX-CMDB推进剂的燃速和DSC特征量随压强的升高而增大,在1~10 MPa压强下该类推进剂的燃速与DSC特征量呈线性相关.

  4. Ab initio study of coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) explosive

    Mohammed, Abdelsalam; Ågren, Hans; Thorvaldsen, Andreas J.; Ruud, Kenneth


    Coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) C 3H 6N 6O 6 molecule is studied by ab initio methods. The results are compared to available experimental observations and against calculations and experimental observations of the conventional non-resonant Raman spectrum for RDX. It is found that all intense bands in the observed CARS spectrum and all Raman differential cross sections are well reproduced by the calculations. The features of the resonant CARS signal vary strongly from the corresponding Raman signal, and are obtained with a considerably larger cross section, a fact that could further facilitate the use of CARS spectroscopy in applications of stand-off detection of gaseous samples at ultra-low concentrations.

  5. Geochemical Trends and Natural Attenuation of RDX, Nitrate, and Perchlorate in the Hazardous Test Area Fractured-Granite Aquifer, White Sands Missile Range, New Mexico, 1996-2006

    Langman, Jeff B.; Robertson, Andrew J.; Bynum, Jamar; Gebhardt, Fredrick E.


    A fractured-granite aquifer at White Sands Missile Range is contaminated with the explosive compound RDX, nitrate, and perchlorate (oxidizer associated with rocket propellant) from the previous use of the Open Burn/Open Detonation site at the Hazardous Test Area. RDX, nitrate, and perchlorate ground-water concentrations were analyzed to examine source characteristics, spatial and temporal variability, and the influence of the natural attenuation processes of dilution and degradation in the Hazardous Test Area fractured-granite aquifer. Two transects of ground-water wells from the existing monitoring-site network - one perpendicular to ground-water flow (transect A-A') and another parallel to ground-water flow (transect B-B') - were selected to examine source characteristics and the spatial and temporal variability of the contaminant concentrations. Ground-water samples collected in 2005 from a larger sampling of monitoring sites than the two transects were analyzed for various tracers including major ions, trace elements, RDX degradates, dissolved gases, water isotopes, nitrate isotopes, and sulfate isotopes to examine the natural attenuation processes of dilution and degradation. Recharge entrains contaminants at the site and transports them downgradient towards the Tularosa Basin floor through a poorly connected fracture system(s). From 1996 to 2006, RDX, nitrate, and perchlorate concentrations in ground water downgradient from the Open Burn/Open Detonation site have been relatively stable. RDX, nitrate, and perchlorate in ground water from wells near the site indicate dispersed contaminant sources in and near the Open Burn/Open Detonation pits. The sources of RDX and nitrate in the pit area have shifted with time, and the shift correlates with the regrading of the south and east berms of each pit in 2002 and 2003 following closure of the site. The largest RDX concentrations were in ground water about 0.1 mile downgradient from the pits, the largest perchlorate

  6. Tertiary Treatment of Effluent from Holston AAP (Army Ammunition Plant) Industrial Liquid Waste Treatment Facility. 4. Ultraviolet Radiation and Hydrogen Peroxide Studies: TNT, RDX, HMX, TAX, and SEX


    AAP Technical Report INDUSTRIAL LIQUID WASTE TREATMENT FACILITY Feb 1983 - Aug 1983 IV. ULTRAVIOLET RADIATION AND HYDROGEN PEROXIDE 1. PERPnRUINe ORO ...ultraviolet light. The production of nitrate-nitrogen and loss of total organic carbon was reportedly indicative of the mineralization of TNT. 5...Treatment of Effluent from Holston AAP Industrial Liquid Waste Treatment Facility. II. Corona Oxidation Studies: TNT, RDX, HMX, TAX, and SEX. Technical

  7. Dietary Supplementation of Magnesium Oxide (MgO) Nanoparticles for Better Survival and Growth of the Freshwater Prawn Macrobrachium rosenbergii Post-larvae.

    Srinivasan, Veeran; Bhavan, Periyakali Saravana; Rajkumar, Gopalan; Satgurunathan, Thangavelu; Muralisankar, Thirunavukkarasu


    This study was performed to assess the growth-promoting potential of dietary magnesium oxide nanoparticles (MgO NPs) in Macrobrachium rosenbergii post-larvae (PL). MgO NPs were supplemented at 0, 100, 200, 300, 400 and 500 mg kg(-1) with the basal diet (containing 0.95 g Mg kg(-1)); the concentrations of Mg in MgO NP-supplemented diets were increased correspondingly (1.07, 1.15, 1.24, 1.37 and 1.46 g Mg kg(-1) respectively). MgO NP-supplemented diets were fed to M. rosenbergii PL (initial weight 0.11 ± 0.04 g) for a period of 90 days. In the carcasses of experimental prawns, the content of Mg was found to be elevated significantly with respect to the individual diet (102.14, 183.29, 205.46, 221.03, 237.10 and 254.36 μg Mg g(-1) respectively) when compared with that of the control. The contents of Cu, Zn, Fe, Ca, Na and K levels were also found to be elevated in the carcasses of experimental prawns. Significant (P MgO NP-supplemented-feed-fed PL. There were no significant elevations recorded in activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)], lipid peroxidation (LPO) and metabolic enzymes [glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT)] recorded in any of the MgO NP-supplemented-feed-fed PL when compared with the control. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed increases in the staining intensity of polypeptide bands resolved in 500 mg kg(-1) MgO NP-supplemented-feed-fed PL when compared with the control. Based on the gradual improvement in attaining survival, growth, FCR, biochemical constituents and haemocyte population, this study recommends MgO NP supplementation of 500 mg kg(-1) for sustainable maintenance of M. rosenbergii PL. As the studied highest concentration of MgO NPs showed the best performance, it is necessary to study with beyond 500 mg kg(-1) of MgO NPs to optimize the actual concentration.

  8. Theoretical insights into effects of molar ratios on stabilities, mechanical properties and detonation performance of CL-20/RDX cocrystal explosives by molecular dynamics simulation

    Hang, Gui-yun; Yu, Wen-li; Wang, Tao; Wang, Jin-tao; Li, Zhen


    The CL-20/RDX cocrystal models with different molar ratios were established by substitution method and molecular dynamics (MD) simulation method was applied to investigate the influences of molar ratios on mechanical properties, stabilities and detonation performance of cocrystal explosives. The crystal parameters, structures, binding energies, mechanical properties and some detonation parameters of different cocrystal explosives were got and compared. The results illustrate that the molar ratio has a direct influence on properties of cocrystal explosive and each of the cocrystal model holds different mechanical properties, binding energies and detonation parameters. The mechanical properties of CL-20/RDX cocrystal explosive can be effectively improved and the cocrystal model with molar ratio in 1:1 has the best mechanical properties. Besides, it has the highest binding energy, so the stability and compatibility is the best. The detonation parameters show that the cocrystal explosive has better detonation performance than RDX. In a word, the cocrystal explosive with molar ratio in 1:1 has the best mechanical properties, highest binding energy and excellent energy density and detonation performance, it is quite promising and can satisfy the requirements of high energy density compounds (HEDC). This paper could offer some theoretical instructions and novel insights for the CL-20 cocrystal explosive designing.

  9. Multivariate functions for predicting the sorption of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-tricyclohexane (RDX) among taxonomically distinct soils.

    Katseanes, Chelsea K; Chappell, Mark A; Hopkins, Bryan G; Durham, Brian D; Price, Cynthia L; Porter, Beth E; Miller, Lesley F


    After nearly a century of use in numerous munition platforms, TNT and RDX contamination has turned up largely in the environment due to ammunition manufacturing or as part of releases from low-order detonations during training activities. Although the basic knowledge governing the environmental fate of TNT and RDX are known, accurate predictions of TNT and RDX persistence in soil remain elusive, particularly given the universal heterogeneity of pedomorphic soil types. In this work, we proposed a new solution for modeling the sorption and persistence of these munition constituents as multivariate mathematical functions correlating soil attribute data over a variety of taxonomically distinct soil types to contaminant behavior, instead of a single constant or parameter of a specific absolute value. To test this idea, we conducted experiments measuring the sorption of TNT and RDX on taxonomically different soil types that were extensively physical and chemically characterized. Statistical decomposition of the log-transformed, and auto-scaled soil characterization data using the dimension-reduction technique PCA (principal component analysis) revealed a strong latent structure based in the multiple pairwise correlations among the soil properties. TNT and RDX sorption partitioning coefficients (KD-TNT and KD-RDX) were regressed against this latent structure using partial least squares regression (PLSR), generating a 3-factor, multivariate linear functions. Here, PLSR models predicted KD-TNT and KD-RDX values based on attributes contributing to endogenous alkaline/calcareous and soil fertility criteria, respectively, exhibited among the different soil types: We hypothesized that the latent structure arising from the strong covariance of full multivariate geochemical matrix describing taxonomically distinguished soil types may provide the means for potentially predicting complex phenomena in soils. The development of predictive multivariate models tuned to a local soil

  10. Experimental Research on Temperature Sensitivity Coefficient of Burning Rate for RDX-CMDB Propellant%RDX-CMDB 推进剂燃速温度敏感系数的实验研究

    裴庆; 赵凤起; 郝海霞; 徐司雨; 张衡


    为了揭示RDX‐CMDB推进剂中各常见组分对其燃速温度敏感系数的影响规律,制备了一系列含RDX、铝粉及燃烧催化剂的CMDB推进剂样品。采用氮气靶线法测得其在2~14MPa下的燃速温度敏感系数(σp)。讨论了RDX含量、铝粉、燃烧催化剂对RDX‐CMDB推进剂燃速温度敏感系数的影响。结果表明,提高工作压强、增加RDX含量、添加燃烧催化剂均有助于降低RDX‐CMDB推进剂在一定初始条件下的燃速温度敏感系数。配方中引入铝粉后可降低中低压下RDX‐CMDB推进剂的燃速温度敏感系数,且燃速温度敏感系数几乎不随压强变化而变化。选用含邻苯二甲酸铅和没食子酸铋锆作燃烧催化剂,均可在2~10MPa下降低RDX‐CMDB推进剂的燃速压强指数,同时降低燃速温度敏感系数。%In order to reveal the effects of the commonly used component on temperature sensitivity coefficient of burning rate for RDX‐CMDB propellant ,a series of propellant samples containing RDX ,aluminium powder and combustion catalyst were prepared .Their temperature sensitivity coefficients of burning rate σP were determined at the pressure of 2MPa to 14MPa by using nitrogen strand burner method .The influences of RDX content ,aluminium powder and combustion cata‐lysts on the temperature sensitivity coefficient of burning rate were discussed .The results show that the increase of working pressure and RDX content and the addition of combustion catalyst are healpful to reduce the temperature sensitivity coeffi‐cient of burning rate of RDX‐CMDB propellant under certain initial conditions .After introducing aluminium powder into the formulation ,the temperature sensitivity coefficient of burning rate of RDX‐CMDB propellant at middle and low pressures can be reduced and is almost not changed with the pressure .Using lead phthalate and bismuth/zirconium gallate as combus‐tion catalyst may reduce pressure exponent of

  11. Novel self-assembled bimetallic structure of Bi/Fe(0): the oxidative and reductive degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Gong, Jianyu; Lee, Chung-Seop; Chang, Yoon-Young; Chang, Yoon-Seok


    A novel self-assembled bimetallic zero-valent bismuth/iron (Bi/Fe(0)) composite was synthesized, characterized, and used successfully to remove hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from wastewater. To assess the oxidative and reductive reactivities of Bi/Fe(0) nanoparticles (NPs), RDX degradation experiments were conducted in either ambient or anaerobic conditions, respectively. The best RDX degradation was achieved using 4%-Bi/Fe(0) (atomic ratio) NPs. In ambient conditions, concentrations of Fe(2+) ions and H2O2 were lower in the Bi/Fe(0) solution than in the Fe(0) solution; this difference indicates that most Fe(2+) ions and H2O2 reacted to produce hydroxyl radicals (*OH) and superoxide radical anions (O2(*-)), thereby resulting in the remarkable degradation of RDX. In anaerobic conditions, the presence of Bi increased the electron generation rate from the surfaces of the Bi/Fe(0) NPs. This increase was responsible for the excellent reductive degradation of RDX. Based on Density Functional Theory (DFT) calculations, the adsorption of water was endothermic on Fe(0) NPs and exothermic on Bi/Fe(0) NPs. Therefore, only the dissociation reactions of H2O in the Bi/Fe(0) system were spontaneous, and these reactions resulted in the prominent reactivity of the Bi/Fe(0) NPs. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Studies on Physico-Mechanical and Explosive Characteristics of RDX/HMX-Based Castable Plastic-Bonded Explosives

    J. S. Gharia


    Full Text Available Conventional cast explosives (RDX/TNT have major drawbacks of poor mechanical properties,shrinkages and higher sensitivity .These properties can be improved by applying plastic bindersystems. The plastic-bonded explosive (PBX is a composite material in which solid explosive particles are dispersed in a polymer matrix. The present paper describes the development of anitramine/hydroxy-terminated polybutadiene (HTPB-based castable PBX. The PBXs were processed as per standard procedures. Bimodal/trimodal particle size system was selected to reach asolid loading of 88 wt per cent. High solid loading was made possible through proper combination ofcoarse/fine ratio of solid ingredients, which was based on a number of tap density experiments.Processability of the binder system was studied by using various wetting agents as well as by selectingbinder/plasticizer ratios. Mechanical properties of the PBXs were enhanced by different crosslinkingagents. The explosive properties ofPBXs including detonation velocity , processability and sensitivityto different types of stimuli, were studied. The results show that PBXs can be manufactured withdetonation properties better than those of composition B/octol with the added advantages of superiorthermal and sensitivity characteristics.

  13. Molecular Design and Property Prediction for a Series of Novel Dicyclic Cyclotrimethylene Trinitramines (RDX) Derivatized as High Energy Density Materials.

    Shen, Cheng; Wang, Pengcheng; Lu, Ming


    Quantum chemistry calculations and thermodynamics methods were carried out to screen out novel high energy density materials (HEDMs) from several new derivatives with dicyclic structures of Cyclotrimethylene trinitramine (RDX). Their volumes, densities, heats of formation, detonation properties and impact sensitivities have been calculated with thermodynamics methods under DFT B3LYP 6-31++g (d, p) level and all of these compounds exhibit good performance as HEDMs. Especially, R4 has given outstanding values as a potential HEDM. Its crystal density (2.07 g/cm(3)), heat of detonation (1.67 kJ/g), detonation velocity (10051m/s), and detonation pressure (48.5 GPa) are even higher than those of CL-20 while its impact sensitivity (h50, 16 cm) remains a relative safety value. The results indicate that the derivative work in common explosives is a good strategy which can design novel HEDMs with high energetic properties and low sensitivity. And furthermore, some mature processes can be used to synthesize them.

  14. Quantitative calibration of vapor levels of TNT, RDX, and PETN using a diffusion generator with gravimetry and ion mobility spectrometry.

    Eiceman, G A; Preston, D; Tiano, G; Rodriguez, J; Parmeter, J E


    A prototype generator for creating a continuous stream of explosive vapor was referenced quantitatively both to a standard weight from the National Institute of Standards and Technology (NIST) and to the response of an ion mobility spectrometer. Vapors from solid explosive, in a precision bore glass tube at constant temperature, diffuse into an inert gas flow. Mass output rates were determined by (1) sample temperature, and (2) sample tube dimensions (length and cross-sectional area). A reference to NIST was achieved gravimetrically though a microbalance calibrated with a reference weight; mass output rates were obtained for 2,4,6-trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX) and pentaerythritol tetranitrate (PETN) at three or more oven temperatures between 79 degrees C and 150 degrees C. The mass output rate was stable over hundreds of hours of continuous operation and the output was adjustable from a few picograms per second to several nanograms per second through variation of the oven temperature. An independent calibration of the vapor generator for TNT at 79 degrees C using an ion mobility spectrometer matched exactly the gravimetric-based findings. In most instances, measured mass output rates compared favorably with theoretically calculated mass output rates, with discrepancies in a few cases resulting primarily from uncertainties in terms (vapor pressures and diffusion coefficients) used to perform the calculations. Agreement is generally not good for PETN, where molecular decomposition contributed to higher than expected measured mass outputs.

  15. Hierarchical multiscale framework for materials modeling: Equation of state implementation and application to a Taylor anvil impact test of RDX

    Barnes, Brian C.; Spear, Carrie E.; Leiter, Ken W.; Becker, Richard; Knap, Jaroslaw; Lísal, Martin; Brennan, John K.


    In order to progress towards a materials-by-design capability, we present work on a challenge in continuum-scale modeling: the direct incorporation of complex physical processes in the constitutive evaluation. In this work, we use an adaptive scale-bridging computational framework executing in parallel in a heterogeneous computational environment to couple a fine-scale, particle-based model computing the equation of state (EOS) to the constitutive response in a finite-element multi-physics simulation. The EOS is obtained from high fidelity materials simulations performed via dissipative particle dynamics (DPD) methods. This scale-bridging framework is progress towards an innovation infrastructure that will be of great utility for systems in which essential aspects of material response are too complex to capture by closed form material models. The design, implementation, and performance of the scale-bridging framework are discussed. Also presented is a proof-of-concept Taylor anvil impact test of non-reacting 1,3,5-trinitrohexahydro-s-triazine (RDX).

  16. Effects of the aluminum content on the shock wave pressure and the acceleration ability of RDX-based aluminized explosives

    Zhou, Z. Q.; Nie, J. X.; Ou, Z. C.; Qin, J. F.; Jiao, Q. J.


    To better understand the influence of the aluminum content on the performance of aluminized explosives, experiments in concrete and cylinder tests were performed. Three types of RDX-based aluminized explosives, in which the mass ratio of aluminum content was 0%, 15%, and 30% were considered in this paper. The shock wave pressures of the aluminized explosives in the affected concrete bodies were measured using manganin pressure sensors. The acceleration ability was obtained using a high-speed camera and a rotating mirror streak camera. The peak pressure attenuation characteristics of the explosives with various aluminum contents indicated that a higher aluminum content is associated with a slower peak pressure attenuation of the shock wave. In addition, the results of the cylinder tests and the metal-rod acceleration tests revealed the influence of the aluminum content on the acceleration ability of explosives in three different time periods. The test data presented in this paper verified the relationship between the aluminum content and explosive performance, which is of great significance for optimizing the properties of aluminized explosives.

  17. High-Temperature CO2 Sorption on Hydrotalcite Having a High Mg/Al Molar Ratio.

    Kim, Suji; Jeon, Sang Goo; Lee, Ki Bong


    Hydrotalcites having a Mg/Al molar ratio between 3 and 30 have been synthesized as promising high-temperature CO2 sorbents. The existence of NaNO3 in the hydrotalcite structure, which originates from excess magnesium nitrate in the precursor, markedly increases CO2 sorption uptake by hydrotalcite up to the record high value of 9.27 mol kg(-1) at 240 °C and 1 atm CO2.

  18. Hyperaccumulation of metals by Thlaspi caerulescens as affected by root development and Cd-Zn/Ca-Mg interactions.

    Saison, Carine; Schwartz, Christophe; Morel, Jean-Louis


    The aim of this work was to study, in a rhizobox experiment, the phytoextraction of metals by the hyperaccumulator plant Thlaspi caerulescens in relation to the heterogeneity of metal pollution. Six treatments were designed with soils containing various levels of metals. Homogeneous soils and inclusions of soils in other soil matrices were prepared in order to vary metal concentration and localization. Growth parameters of the plant (rosette diameter and shoot biomass) and localization of roots and shoot uptake of Zn, Cd, Ca, and Mg were determined after 10 weeks of growth. The plants grown on the polluted industrial soils provided a larger biomass and had lower mortality rates than those grown on the agricultural soil. Moreover, these plants accumulated more Zn and Cd (up to 17,516 and 375 mg kg(-1) DM, respectively) than plants grown on the agricultural soil (up to 7300 mg Zn kg(-1) and 83 mg Cd kg(-1) DM). The roots preferentially explored metal-contaminated areas. The exploration of polluted soil inclusions by the roots was associated with a higher extraction of metals. Zinc and Cd in the shoots of Thlaspi caerulescens were negatively correlated with Ca and Mg concentrations; however, the soil supply for these two elements was identical. This suggests that there is competition for the uptake of these elements and that Zn is preferentially accumulated.

  19. Experimental and TD-DFT study of optical absorption of six explosive molecules: RDX, HMX, PETN, TNT, TATP, and HMTD.

    Cooper, Jason K; Grant, Christian D; Zhang, Jin Z


    Time dependent density function theory (TD-DFT) has been utilized to calculate the excitation energies and oscillator strengths of six common explosives: RDX (1,3,5-trinitroperhydro-1,3,5-triazine), β-HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), TATP (triacetone triperoxide), HMTD (hexamethylene triperoxide diamine), TNT (2,4,6-trinitrotoluene), and PETN (pentaerythritol tetranitrate). The results were compared to experimental UV-vis absorption spectra collected in acetonitrile. Four computational methods were tested including: B3LYP, CAM-B3LYP, ωB97XD, and PBE0. PBE0 outperforms the other methods tested. Basis set effects on the electronic energies and oscillator strengths were evaluated with 6-31G(d), 6-31+G(d), 6-31+G(d,p), and 6-311+G(d,p). The minimal basis set required was 6-31+G(d); however, additional calculations were performed with 6-311+G(d,p). For each molecule studied, the natural transition orbitals (NTOs) were reported for the most prominent singlet excitations. The TD-DFT results have been combined with the IPv calculated by CBS-QB3 to construct energy level diagrams for the six compounds. The results suggest optimization approaches for fluorescence based detection methods for these explosives by guiding materials selections for optimal band alignment between fluorescent probe and explosive analyte. Also, the role of the TNT Meisenheimer complex formation and the resulting electronic structure thereof on of the quenching mechanism of II-VI semiconductors is discussed.

  20. Molecular dynamics simulations of hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) using a combined Sorescu-Rice-Thompson AMBER force field.

    Agrawal, Paras M; Rice, Betsy M; Zheng, Lianqing; Thompson, Donald L


    We present the results of molecular dynamics simulations of crystalline hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) using the SRT-AMBER force field (P. M. Agrawal et al., J. Phys. Chem. B 2006, 110, 5721), which combines the rigid-molecule force field developed by Sorescu-Rice-Thompson (D. C. Sorescu, B. M. Rice, and D. L. Thompson, J. Phys. Chem. B 1997, 101, 798) with the intramolecular interactions obtained from the Generalized AMBER Force Field (Wang et al., J. Comput. Chem. 2004, 25, 1157). The calculated crystal density at room conditions is about 10% lower than the measured value, while the lattice parameters and thermodynamic melting point are within about 5% at ambient pressure. The chair and inverted chair conformation, bond lengths, and bond angles of the RDX molecule are accurately predicted; however, there are some inaccuracies in the calculated orientations of the NO2 groups. The SRT-AMBER force field predicts overall reasonable results, but modifications, probably in the torsional parameters, are needed for a more accurate force field.

  1. 含氟介质中乌洛托品硝解制RDX研究%Preparation of RDX by Nitrolysis of Hexamethylenetetramine in Fluorous Media

    易文斌; 蔡春


    以全氟辛基磺酸(C8F17SO3H,PfOS)和全氟萘烷(C10F18,顺式与反式的混合物)分别为催化剂和氟溶剂,用硝酸硝解乌洛托品制备黑索今(RDX).过程比传统方法产生更少的废酸和硝酸盐.考察了硝酸、催化剂和硝酸铵用量,反应温度,反应时间,以及氟-水两相相比对反应的影响.研究表明,当硝酸和硝酸铵摩尔用量分别为底物的10倍和0.5倍时,用摩尔分数为10%的PfOS作催化剂,乌洛托品在20 ℃下反应6 h后得到RDX,得率为129.4%(以1 mol乌洛托品生成1 mol RDX计算).含有催化剂的氟相通过简单的相分离,就可回收利用,氟相重复使用5次,其催化活性减少不大.

  2. Relationship between Drop Energy and Heat Explosion Parameters of RDX-based Aluminized Explosives%RDX基含铝炸药的特性落高能与热爆发参数的关系

    郑亚峰; 常海; 张修博; 刘子如; 陆洪林; 任晓宁; 王晓红


    The thermal explosion temperature (Tb) was determined by heat explosion test and the drop height ( H50) was obtained by impact sensitivity test for 12 types of RDX-based aluminized explosives with different contents of RDX and aluminum powder respectively. The heat explosion parameters decreased to the lowest when RDX content reaches 89% ( Tb, heat explosion activation energy(Eb) and logarithm of pre-expontential factor(InA)), and drop energies ( Edr) were calculated with experiment data. The results show that the drop height ( H50) first fall down and then rise with the increasing of RDX contents. Additionally, it is found that a linear relationship exists between the drop energies ( Edr) and heat explosion parameters ( Tb, fb and In/A).%分别采用热爆发延滞期试验和撞击感度试验测定了12种不同RDX和铝粉含量的含铝炸药的5 s爆发点(Tb)和特性落高(H50),并根据实验数据计算出热爆发参数(Eb和InA)和特性落高能(Edr).结果表明:随着RDX含量的增加,特性落高先减小后逐渐升高,特性落高能(Edr)与热爆发参数(Tb、Eb和InA)之间存在线性关联关系.

  3. Comparison of rizatriptan 5 mg and 10 mg tablets and sumatriptan 25 mg and 50 mg tablets.

    Kolodny, A; Polis, A; Battisti, W P; Johnson-Pratt, L; Skobieranda, F


    This randomized, double-blind, two-attack, placebo-controlled, crossover study explored the efficacy and tolerability of rizatriptan 10 mg compared with sumatriptan 50 mg as well as rizatriptan 5 mg compared with sumatriptan 25 mg in the acute treatment of migraine. Following randomization to one of six possible treatment sequences, patients (n = 1447) treated two sequential attacks, of moderate or severe intensity, separated by at least 5 days. Patients assessed pain severity, migraine-associated symptoms, and functional disability at 0.5, 1, 1.5, and 2 h post treatment. Compared with placebo, all treatments were effective. On the primary endpoint of time to pain relief, rizatriptan 10 mg was not statistically different from sumatriptan 50 mg [odds ratio (OR) 1.10, P = 0.161], and rizatriptan 5 mg was statistically superior to sumatriptan 25 mg (OR 1.22, P = 0.007). In general, rizatriptan 10 mg and 5 mg treatment resulted in improvement compared with the corresponding doses of sumatriptan on measures of pain severity, migraine symptoms, and functional disability and the 5-mg dose reached statistical significance on almost all measures. All treatments were generally well tolerated.

  4. Multivariate soil fertility relationships for predicting the environmental persistence of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-tricyclohexane (RDX) among taxonomically distinct soils.

    Katseanes, Chelsea K; Chappell, Mark A; Hopkins, Bryan G; Durham, Brian D; Price, Cynthia L; Porter, Beth E; Miller, Lesley F


    After nearly a century of use in numerous munition platforms, TNT and RDX contamination has turned up largely in the environment due to ammunition manufacturing or as part of releases from low-order detonations during training activities. Although the basic knowledge governing the environmental fate of TNT and RDX are known, accurate predictions of TNT and RDX persistence in soil remain elusive, particularly given the universal heterogeneity of pedomorphic soil types. In this work, we proposed overcoming this problem by considering the environmental persistence of these munition constituents (MC) as multivariate mathematical functions over a variety of taxonomically distinct soil types, instead of a single constant or parameter of a specific absolute value. To test this idea, we conducted experiments where the disappearance kinetics of TNT and RDX were measured over a >300 h period in taxonomically distinct soils. Classical fertility-based soil measurements were log-transformed, statistically decomposed, and correlated to TNT and RDX disappearance rates (k-TNTand k-RDX) using multivariate dimension-reduction and correlation techniques. From these efforts, we generated multivariate linear functions for k parameters across different soil types based on a statistically reduced set of their chemical and physical properties: Calculations showed that the soil properties exhibited strong covariance, with a prominent latent structure emerging as the basis for relative comparisons of the samples in reduced space. Loadings describing TNT degradation were largely driven by properties associated with alkaline/calcareous soil characteristics, while the degradation of RDX was attributed to the soil organic matter content - reflective of an important soil fertility characteristic. In spite of the differing responses to the munitions, batch data suggested that the overall nutrient dynamics were consistent for each soil type, as well as readily distinguishable from the other soil

  5. Substitution of Mn for Mg in MgB_2*

    Fitzpatrick, Michael D.; Johnston, David C.; Miller, Lance L.; Hill, Julienne M.


    The study of solid solutions in which the Mg in MgB2 is partially replaced by magnetic 3d or 4f atoms can potentially reveal important information on the superconducting state of MgB_2. As an end-member of the hypothetical Mg_1-xMn_xB2 system, MnB2 is isostructural with MgB2 and is an antiferromagnet below TN = 760 K which becomes canted at 157 K. A previous study by Moritomo et al.[1] examined the structure and properties of multi-phase samples with 0.01J. Phys. Soc. Japan b70, 1889 (2001).; “Effects of transition metal doping in MgB2 superconductor", Y. Moritomo at al. arXiv:cond-mat/0104568.

  6. Mesoporous carbon stabilized MgO nanoparticles synthesized by pyrolysis of MgCl2 preloaded waste biomass for highly efficient CO2 capture.

    Liu, Wu-Jun; Jiang, Hong; Tian, Ke; Ding, Yan-Wei; Yu, Han-Qing


    Anthropogenic CO2 emission makes significant contribution to global climate change and CO2 capture and storage is a currently a preferred technology to change the trajectory toward irreversible global warming. In this work, we reported a new strategy that the inexhaustible MgCl2 in seawater and the abundantly available biomass waste can be utilized to prepare mesoporous carbon stabilized MgO nanoparticles (mPC-MgO) for CO2 capture. The mPC-MgO showed excellent performance in the CO2 capture process with the maximum capacity of 5.45 mol kg(-1), much higher than many other MgO based CO2 trappers. The CO2 capture capacity of the mPC-MgO material kept almost unchanged in 19-run cyclic reuse, and can be regenerated at low temperature. The mechanism for the CO2 capture by the mPC-MgO was investigated by FTIR and XPS, and the results indicated that the high CO2 capture capacity and the favorable selectivity of the as-prepared materials were mainly attributed to their special structure (i.e., surface area, functional groups, and the MgO NPs). This work would open up a new pathway to slow down global warming as well as resolve the pollution of waste biomass.

  7. Avaliação de contaminação por mercúrio em Descoberto, MG Evaluation of mercury contamination in Descoberto, MG

    Ana Amélia Paulino Tinôco


    Full Text Available O mercúrio, elemento químico considerado não essencial a qualquer processo metabólico, é facilmente acumulado na maioria dos organismos. Ocorre naturalmente em formas orgânicas e inorgânicas, nos estados sólido, dissolvido e gasoso. Seu ciclo biogeoquímico envolve processos que ocorrem no solo, na água e na atmosfera. Em 2002, descobriu-se mercúrio elementar na zona rural do município de Descoberto, Minas Gerais, onde moram cerca de 70 famílias, e sua origem parece estar associada à exploração de ouro, que existiu na região no século 19. Neste trabalho, foram escolhidas três áreas para identificar possível contaminação da água, solo, sedimento e peixes por mercúrio, bem como para estabelecer valores de referência local e contraprova de resultados obtidos anteriormente. Verificaram-se elevadas concentrações no solo (0,26 a 0,55, sedimentos (0,13 a 0,61 e água (Mercury is a chemical element considered unessential to any metabolic process; however, it is easily accumulated in most organisms. It is naturally found in both organic and inorganic forms in solid, liquid and vapor states. Its biogeochemical cycle involves processes occurring in the soil, water and the atmosphere. In 2002, elementary mercury was found in the city of Descoberto, Minas Gerais, Brazil, where 70 families live, and its origin may be related to gold exploration that happened in this region in the 19th century. In this work, three areas were chosen to identify a possible mercury contamination of water, soil, sediment and fish samples and to establish local reference values and counter-evidence of the data previously obtained. Based on the results, high mercury concentrations in soil (0.26 to 0.55, sediments (0.13 to 0.61 and water (< 0.2 to 2,10 µg.L-1 were verified.

  8. Negative-ion formation in the explosives RDX, PETN, and TNT using the Reversal Electron Attachment Detection (READ) technique

    Chutijian, Ara; Boumsellek, S.; Alajajian, S. H.


    reversing their direction with electrostatic fields. At this turning point the electrons have zero or near-zero energy. A beam of target molecules is introduced, and the resultant negative ions extracted. This basic idea has been recently improved to allow for better reversal geometry, higher electron currents, lower backgrounds, and increased negative-ion extraction efficiency. We present herein application of the so-called reversal electron attachment detector (READ) to the study of negative-ion formation in the explosives molecules RDX, PETN, and TNT under single-collision conditions.

  9. Influence of Ultrasound on the Washing Effect of RDX Containing Crystal Acid%超声波对RDX晶体酸清洗效果的影响

    张幺玄; 胡秀娟; 陈厚和


    采用超声空化阈值理论计算并结合超声波清洗技术,研究了超声波对RDX晶体酸清洗效果的影响.结果表明,超声波阈值声压、阈值声强随着空化泡初始半径的增大和流体温度的升高而减少.小的初始半径和更高的温度易产生超声空化.随着温度的增加,RDX晶体酸值逐渐降低,RDX晶体酸清洗效果越来越好,但是当温度升高到一定值时,酸值变化不是很明显.超声频率低的清洗效果要优于频率高的清洗效果.增大超声功率,RDX晶体酸值先降低后略有升高,表明适当增加超声功率会降低RDX酸值,但过度提高超声功率反而使酸值增加,影响清洗效果.%The influence of ultrasound on the washing effect of RDX containing acid was investigated by the theoretical calculation of cavitation threshold of ultrasound and an ultrasound cleaning technology.The results indicated that the threshold of ultrasonic pressure and threshold of ultrasonic intensity decreased with the increase in the original radius and the temperature of the fluid used for washing.Smaller original radius and higher temperature were propitious to ultrasound cavitation.As the temperature increasing,acid value of RDX decreased gradually,implying that washing effect was getting better,but when the temperature was up to a certain value,the variation of acid value was not obvious.The cleaning effect at low frequencies of ultrasound was superior to that at high frequencies.When increasing the ultrasonic power,the acid value of the water-RDX-acid system went down firstly,then up slightly,showing that appropriate increase in ultrasonic power would reduce the acid value,on the contrary,the excessive increase in ultrasonic power would increase acid value,weakening the washing effect.

  10. Application of RDX extraction techniques from waste NC-based propellants%从NC基推进剂中提取RDX等有效成分的设计

    贾林; 张林军; 张冬梅; 杜姣姣; 王琼; 杨彩宁; 王明


    In order to recycle and utilize useful component cyclotrimethylenetrinitramine ( RDX) in waste nitrocellulose( NC)⁃based propellant, the extraction methods of ultra sound⁃assisted extraction ( UAE ) , open⁃focus⁃microwave⁃assisted extraction (MAE), pressurized liquid extraction (PLE), soxlet's extraction (SE) and organic⁃solvent⁃dissolve⁃water⁃precipitation (SDWP) were studied in lab. The results, which were characterized by HPLC and IR, show that the method of PLE, in which CH2 Cl2 is used as extractant is efficient and time⁃saving compared with the other methods. In the method of PLE, the high pressure can pre⁃vent the volatilzation and decomposition of nitroglycerin (NG).The completely different dissolving performance of RDX and NC in CH2Cl2 is beneficial to seperation of them. PLE is expected to be practically applied to recycle and utilization of useful component RDX from a lot of waste NC based propellant.%为了对退役硝化棉( NC)基固体推进剂中黑索今( RDX)等有效成分进行回收再利用,研究了实验室级别的现代超声辅助提取法( UAE)、开放式聚焦微波辅助提取法( MAE)、加压加热提取法( PLE)及传统的索式提取法( SE)、溶剂溶解水析出法(SDWP),用液相色谱法、红外光谱法对提取效果进行表征。结果表明,PLE的高压可防止硝化甘油(NG)的挥发和分解,用CH2 Cl2作提取剂,能很好溶解RDX等待测物、完全不溶解NC,使得提取物和NC容易分离,提取效率高、时间短,优于其他方法,有望实际应用于大量的退役NC基推进剂中RDX等有效组分的回收利用。

  11. Understanding and Predicting the Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Experimental Measurements of Material Properties and Reaction Violence

    Maienschein, J L; Wardell, J F; Weese, R K; Cunningham, B J; Tran, T D


    The violence of thermal explosions with energetic materials is affected by many material properties, including mechanical and thermal properties, thermal ignition kinetics, and deflagration behavior. These properties must be characterized for heated samples as well as pristine materials. We present available data for these properties for two HMX-based formulations--LX-04 and PBX-9501, and two RDX-based formulations--Composition B and PBXN-109. We draw upon separately published data on the thermal explosion violence with these materials to compare the material properties with the observed violence. We have the most extensive data on deflagration behavior of these four formulations, and we discuss the correlation of the deflagration data with the violence results. The data reported here may also be used to develop models for application in simulation codes such as ALE3D to calculate and Dredict thermal explosion violence.

  12. Novel self-assembled bimetallic structure of Bi/Fe{sup 0}: The oxidative and reductive degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    Gong, Jianyu; Lee, Chung-Seop [School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Chang, Yoon-Young [Department of Environmental Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Chang, Yoon-Seok, E-mail: [School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)


    Highlights: • A novel bimetallic nanoparticle of Bi-nZVI was successfully synthesized. • The highest degradation rate of RDX obtained on 4% Bi-nZVI. • Bi-nZVI shows much higher reactivity than other noble-metal modified ZVI. • The concentration of ·OH generated by Bi-nZVI is much higher than that of nZVI. • The adsorption processes of water on Bi/Fe (1 1 0) were exothermic process. - Abstract: A novel self-assembled bimetallic zero-valent bismuth/iron (Bi/Fe{sup 0}) composite was synthesized, characterized, and used successfully to remove hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from wastewater. To assess the oxidative and reductive reactivities of Bi/Fe{sup 0} nanoparticles (NPs), RDX degradation experiments were conducted in either ambient or anaerobic conditions, respectively. The best RDX degradation was achieved using 4%-Bi/Fe{sup 0} (atomic ratio) NPs. In ambient conditions, concentrations of Fe{sup 2+} ions and H{sub 2}O{sub 2} were lower in the Bi/Fe{sup 0} solution than in the Fe{sup 0} solution; this difference indicates that most Fe{sup 2+} ions and H{sub 2}O{sub 2} reacted to produce hydroxyl radicals (·OH) and superoxide radical anions (O{sub 2}·{sup −}), thereby resulting in the remarkable degradation of RDX. In anaerobic conditions, the presence of Bi increased the electron generation rate from the surfaces of the Bi/Fe{sup 0} NPs. This increase was responsible for the excellent reductive degradation of RDX. Based on Density Functional Theory (DFT) calculations, the adsorption of water was endothermic on Fe{sup 0} NPs and exothermic on Bi/Fe{sup 0} NPs. Therefore, only the dissociation reactions of H{sub 2}O in the Bi/Fe{sup 0} system were spontaneous, and these reactions resulted in the prominent reactivity of the Bi/Fe{sup 0} NPs.

  13. P2X7 Receptor Mediated Growth-Inhibitory Effect in KG1 a Cell Line

    Xiujun Zhang; Lijun Meng


    This study was conducted to investigate ATP-induced growth inhibition in human leukemic cells KGla.METHoDS ATP inhibited cell growth was analyzed by MTSassay.Extemalization of phosphatidylserine could be detected byAnnexin-V-FITC apoptosis staining after activation of the P2X7 re-ceptor.P2X7 mediated pore formation was detected in KGla cellsby Yo-Pro-1 uptake assay.RESUlTS ATP inhibited cell growth in a dose-dependent man-ner.The cytotoxic effect could be blocked by P2X7 antagonists,oxidized ATP(OATP)and KN62.Externalization of phosphatidyl-serine could be detected in a time-dependent manner.P2X7 medi-ated pore forigation could be detected in KGla cells.These effectscould not be observed in P2X7 null Ramos cells.CONCLUSIoN The results and our previously reports thatmRNA,protein expression and calcium response of the P2X7receptor in KGla cells,suggested that extracellular ATP effectivelyinduces growth inhibition through apoptosis in KGla cells byactivation of P2X7 receptor,and that may be mediated by extracel-lular Ca2+ineux and pore formation.

  14. 联合检测幽门螺杆菌CagA、VacA、Ure、Hsp60及RdxA的临床价值%Clinical value of combined detection of CagA, VacA, Ure,Hsp60 and RdxA in Helicobacter pylori

    陈海潮; 单平囡; 许德顺


    目的 探讨联合检测幽门螺杆菌细胞毒素相关蛋白(CagA)、空泡毒素相关蛋白(VacA)、尿素酶(Ure)、热休克蛋白60(Hsp60)和氮素还原酶(RdxA)在胃、十二指肠疾病中的临床价值.方法 对486例患者以免疫斑点试验(蛋白芯片)检测幽门螺杆菌CagA、VacA、Ure、Hsp60及RdxA抗体,对照组106例为健康体检人员.结果 患者组中CagA、VacA、Ure、Hsp60的总阳性率分别为65.02%、52.67%、71.40%、11.74%,均明显高于对照组(P<0.01);CagA、VacA和Ure检测对萎缩性胃炎、胃癌的阳性率为80.00%~90.00%,对胃、十二指肠溃疡的阳性率为70.00%~78.00%,其余的阳性率均<74.00%,但VacA、Ure、Hsp60检测对胃癌的阳性率均为89.47%.结论 5种Hp抗体检测对表浅性胃炎、萎缩性胃炎、胃,十二指肠溃疡及胃癌诊治有较高参考价值.%OBJECTIVE To study the clinical value of combined detection of CagA, VacA, Ure, Hsp60 ,and RdxA in Helicobacter pylori in the diagnosis and treatment of the gaster-duodenum disease. METHODS The antibodies of CagA, VacA, Ure, Hsp60 and RdxA of H. pylori for 486 patients and 106 personnel of health-examination were detected by the immunospot test (protein array). RESULTS The total positive rates of CagA, VacA, Ure, Hsp60 and RdxA (65.02%. 52.67%, 71.40%, 11. 73% .respectively ) in the patient group were significantly higher than those in the control group(P<0. 001) ; the positive rates of CagA, VacA, and Ure for the detection of atrophic gastritis and gastric cancer varied from 80. 00% to 90. 00%, gaster-duodenum ulcer varied from 70.00% to 78. 00% ,others less than 74. 00% , but the positive rates of VacA, Ure and Hsp60 for the detection of gastric cancer were 89. 47% all. CONCLUSION The detection of 5 Hp antibodies has significant value in diagnosis and treatment of superficial gastritis, atrophic gastritis, gaster-duodenum ulcer, and gastric cancer.

  15. Mg spin affects adenosinetriphosphate activity

    Tulub, Alexander A


    The Schlegel-Frisch ab initio molecular dynamics (ADMP) (DFT:B3LYP), T = 310 K, is used to study complexation between adenosinetriphosphate (ATP), ATP subsystem, and magnesium cofactor [Mg(H2O)6]2+, Mg subsystem, in a water pool, modeled with 78 water molecules, in singlet (S) and triplet (T) states. The computations prove that the way of ATP cleavage is governed by the electron spin of Mg. In the S state Mg prefers chelation of \\gamma-\\beta-phosphate oxygens (O1-O2), whereas in the T state it chelates \\beta-\\alpha-phosphate oxygens (O2-O3) or produces a single-bonded intermediate. Unlike the chelates, which initiate ionic reaction paths, the single-bonded intermediate starts off a free-radical path of ATP cleavage, yielding a highly reactive adenosinemonophosphate ion-radical, .AMP-, earlier observed in the CIDNP (Chemically Induced Dynamic Nuclear Polarization) experiment (A.A. Tulub, 2006). The free-radical path is highly sensitive to Mg nuclear spin, which through a hyperfine interaction favors the produc...


    邵颖惠; 任晓宁; 刘子如; 王晓红; 张皋


    The Non-isothermal crystallization of DNAN in RDX and AP was studied by Differential Scanning Calorimetry ( DSC). The results showed that the super-cooling degree and eliminate heating-self of DNAN could be reduced effect by adding AP. DNAN and its non-isothermal crystallization in RDX and AP could be described by Avrami equation, the Avrami exponent n showed that the mechanism function of DNAN in RDX and in AP was different from each other, the crystallization activation energies Ea. Of pure DNAN had graeter value compared with that in RDX and in AP, and the reduced value of Ea was relation to its nucleus mechanism.%采用低温差示扫描量热技术(DSC)研究了2,4-二硝基苯甲醚(DNAN)熔体及其分别在RDX和AP介质中的非等温结晶行为.结果表明,AP能够有效降低DNAN结晶过冷度,消除自加热.DNAN及其在RDX和AP介质中的非等温结晶过程可以用Avrami方程描述,获得的Avrami指数n表明DNAN在RDX和AP两种介质的结晶机理发生了不同变化,DNAN纯熔体的结晶过程具有较高的表观活化能Ea,在RDX和AP介质中Ea值有不同程度的下降,这与它的成核机理有关.

  17. Clostridium geopurificans strain MJ1 sp. nov., a strictly anaerobic bacterium that grows via fermentation and reduces the cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    Kwon, Man Jae; Wei, Na; Millerick, Kayleigh; Popovic, Jovan; Finneran, Kevin


    A fermentative, non-spore forming, motile, rod-shaped bacterium, designated strain MJ1(T), was isolated from an RDX contaminated aquifer at a live-fire training site in Northwest NJ, United States. On the basis of 16S rRNA gene sequencing and DNA base composition, strain MJ1(T) was assigned to the Firmicutes. The DNA G+C content was 42.8 mol%. Fermentative growth was supported by glucose and citrate in a defined basal medium. The bacterium is a strict anaerobe that grows between at pH 6.0 and pH 8.0 and 18 and 37 °C. The culture did not grow with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as the electron acceptor or mineralize RDX under these conditions. However, MJ1(T) transformed RDX into MNX, methylenedinitramine, formaldehyde, formate, ammonium, nitrous oxide, and nitrate. The nearest phylogenetic relative with a validly published name was Desulfotomaculum guttoideum (95 % similarity). However, MJ1(T) was also related to Clostridium celerecrescens DSM 5628 (95 %), Clostridium indolis DSM 755 (94 %), and Clostridium sphenoides DSM 632 (94 %). DNA:DNA hybridization with these strains was between 6.7 and 58.7 percent. The dominant cellular fatty acids (greater than 5 % of the total, which was 99.0 % recovery) were 16:0 fatty acid methyl ester (FAME) (32.12 %), 18:1cis 11 dimethyl acetal (DMA) (16.47 %), 16:1cis 9 DMA (10.28 %), 16:1cis 9 FAME (8.10 %), and 18:1cis 9 DMA (5.36 %). On the basis of morphological, physiological, and phylogenetic data, Clostridium geopurificans is proposed as a new species in genus Clostridium, with strain MJ1(T) as the type strain.

  18. Soil properties affect the toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the enchytraeid worm Enchytraeus crypticus.

    Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Phillips, Carlton T; Kolakowski, Jan E; Lanno, Roman


    The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific. © 2013 SETAC.

  19. Use of pressurized liquid extraction (PLE)/gas chromatography-electron capture detection (GC-ECD) for the determination of biodegradation intermediates of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in soils.

    Zhang, Baohong; Pan, Xiaoping; Cobb, George P; Anderson, Todd A


    A rapid, sensitive, and reproducible method was developed for quantitative determination of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its biodegradation intermediates, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in soils. RDX, MNX, DNX, or TNX was extracted from soil by pressurized liquid extraction (PLE), followed by cleanup using florisil. Instrumental analysis was performed using gas chromatography with electron capture detection (GC-ECD), which was highly sensitive to the parent explosive and its metabolites. The method detection limits (MDLs) were 0.243, 0.095, 0.138, and 0.057 ng/g for RDX, MNX, DNX, and TNX, respectively. The method gave high recovery (98-102%), good precision (0.22-5.14%), and reproducibility, and proved to be suitable for real world sample analysis.

  20. A comparative study of 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) and Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under high pressures using Raman spectroscopy and DFT calculations

    Zeng, Yangyang; Song, Yunfei; Yu, Guoyang; Zheng, Xianxu; Guo, Wencan; Zhao, Jun; Yang, Yanqiang


    High pressure Raman experiment was performed to compare RDX and HMX crystals. Ab initio calculations using B3LYP Density Functional Theory method with Sadlej's medium-sized polarized basis set (SadlejpVTZ) were carried out for Caae RDX and 1,5-diaxial-3,7-diequatorial chair HMX molecules. Our calculations and measured Raman vibrational spectra reveal both molecules have similarities on bonding and vibrational properties at ambient pressure. However, high pressure responses for both molecules aren't the same. For RDX, at pressure near 4 GPa, a number of changes become apparent in the Raman spectra, such as modes splitting, intensity modification, and discontinuity of pressure-dependence of frequency shifts, which are consistent with previous experiment and believed to associate with α-γ phase transition. For HMX, only slight conformational deformation involving NO2 group was observed, and was considered as an onset of β-ε phase transition. It is proposed that the markedly different behavior under high pressure for these two molecules results from different molecular packing in unit cell.

  1. CsMgPO4

    Nikolay S. Slobodyanik


    Full Text Available Caesium magnesium orthophosphate is built up from MgO4 and PO4 tetrahedra (both with . m. symmetry linked together by corners, forming a three-dimensional framework. The Cs atoms have .m. site symmetry and are located in hexagonal channels running along the a- and b-axis directions.

  2. PNI 对 RDX/Al-CMDB 推进剂燃烧性能的影响%Effect of PNI on the Combustion Properties of RDX/Al-CMDB Propellant

    袁志锋; 赵凤起; 杨立波; 郑晓东; 张超; 田军


    The RDX/Al-CMDB propellants containing 4-initroimidazole lead salt (PNI)were prepared by an absorp-tion/rolling method.The burning rates of propellants were measured by a target line method.The effect of PNI/carbon,PNI/carbon/stabilizer,PNI/Pb salts on the combustion properties of RDX/Al-CMDB propellants were studied.The results show that PNI is an effective energetic burning catalyst.The combination of PNI with carbon black orβ-Pb salt makes the mesa effect or plateau of CMDB propellant appear.When the mass fraction of PNI is 4. 0%,it makes the pressure exponent of propellant decrease to 0.07.The combination of 1 .0% PNI and 2.5% β-Pb salt makes the pressure exponent of propellant decrease to -0.13.The burning rate of RDX/Al-CMDB propellants containing PNI is adjustable and can appear the plateau or mesa effect.%采用吸收-压延方法制备了含4-硝基咪唑铅盐(PNI)的 RDX/Al-CMDB 推进剂样品,用靶线法测试了其燃速,研究了 PNI 与炭黑组成的二组元催化剂,PNI、炭黑和安定剂组成的三组元催化剂,PNI 与不同种类铅盐组成的多组元催化剂对 RDX/Al-CMDB 推进剂燃烧性能的影响。结果表明,PNI 是一种有效的含能燃烧催化剂;PNI 与炭黑或β铅盐的混合物可使推进剂出现平台或麦撒燃烧;当 PNI 的质量分数为4.0%时,推进剂的压强指数降至0.07;1.0%PNI 和2.5%β-Pb 的混合物使推进剂的压强指数降至-0.13。含 PNI 改性双基推进剂的燃速可调,出现平台或麦撒区间。

  3. PKCη/Rdx-driven phosphorylation of PDK1: a novel mechanism promoting cancer cell survival and permissiveness for parvovirus-induced lysis.

    Séverine Bär


    Full Text Available The intrinsic oncotropism and oncosuppressive activities of rodent protoparvoviruses (PVs are opening new prospects for cancer virotherapy. Virus propagation, cytolytic activity, and spread are tightly connected to activation of the PDK1 signaling cascade, which delays stress-induced cell death and sustains functioning of the parvoviral protein NS1 through PKC(η-driven modifications. Here we reveal a new PV-induced intracellular loop-back mechanism whereby PKCη/Rdx phosphorylates mouse PDK1:S138 and activates it independently of PI3-kinase signaling. The corresponding human PDK1phosphoS135 appears as a hallmark of highly aggressive brain tumors and may contribute to the very effective targeting of human gliomas by H-1PV. Strikingly, although H-1PV does not trigger PDK1 activation in normal human cells, such cells show enhanced viral DNA amplification and NS1-induced death upon expression of a constitutively active PDK1 mimicking PDK1phosphoS135. This modification thus appears as a marker of human glioma malignant progression and sensitivity to H-1PV-induced tumor cell killing.

  4. PETN, RDX, HMX, TATB: band gap dependence on pressure under hydrostatic compression from DFT with GW and vdW corrections

    Mukhanov, Andrei; Yanilkin, Alexei


    In the middle of 1990s Gilman (Gilman J. J. 1995 Phil. Mag. B, 71:6, 1057) proposed the idea that explosives transit from insulator to conductor state with following adiabatic expansion of free electrons in shockwave. One of the reasons of such a behavior of electrons is narrowing or disappearing of the fundamental band gap in explosive single crystal. It is well known that similar behavior can be simulated by DFT. But there is a severe problem of lowering the value of gap by DFT. So for quantitative prediction of narrowing of gap under pressure it is necessary to use more complicated methods like GW. From first principle calculations we determined elastic moduli for ideal crystals of PETN, RDX, HMX, and TATB. Accounting for those moduli we simulated the 0 K isotherms for hydrostatic compression of single crystal. Due to the essential role of van der Waals interaction in such materials the vdW corrections to DFT in Grimme's form was used. We obtained the dependencies for band gap on pressure under hydrostatic compression. Our preliminary results on GW calculations show that for TATB at initial uncompressed volume we have the value of gap twice a bigger in GW than in DFT.

  5. Free-energy calculations using classical molecular simulation: application to the determination of the melting point and chemical potential of a flexible RDX model.

    Sellers, Michael S; Lísal, Martin; Brennan, John K


    We present an extension of various free-energy methodologies to determine the chemical potential of the solid and liquid phases of a fully-flexible molecule using classical simulation. The methods are applied to the Smith-Bharadwaj atomistic potential representation of cyclotrimethylene trinitramine (RDX), a well-studied energetic material, to accurately determine the solid and liquid phase Gibbs free energies, and the melting point (Tm). We outline an efficient technique to find the absolute chemical potential and melting point of a fully-flexible molecule using one set of simulations to compute the solid absolute chemical potential and one set of simulations to compute the solid-liquid free energy difference. With this combination, only a handful of simulations are needed, whereby the absolute quantities of the chemical potentials are obtained, for use in other property calculations, such as the characterization of crystal polymorphs or the determination of the entropy. Using the LAMMPS molecular simulator, the Frenkel and Ladd and pseudo-supercritical path techniques are adapted to generate 3rd order fits of the solid and liquid chemical potentials. Results yield the thermodynamic melting point Tm = 488.75 K at 1.0 atm. We also validate these calculations and compare this melting point to one obtained from a typical superheated simulation technique.

  6. Formation of Mg2Ni with enhanced kinetics: Using MgH2 instead of Mg as a starting material

    Zhao, Bin; Fang, Fang; Sun, Dalin; Zhang, Qingan; Wei, Shiqiang; Cao, Fenglei; Sun, Huai; Ouyang, Liuzhang; Zhu, Min


    At a temperature over the decomposition point (375 °C) of MgH2, the formation of Mg2Ni is greatly enhanced from the 2MgH2+Ni system, as compared to the 2Mg+Ni system. In support of this finding, in-situ observation of X-ray absorption fine structure of the two systems indicates that MgNi bonds form faster in the 2MgH2+Ni system than in the 2Mg+Ni system. Furthermore, theoretical modeling also shows that Mg atoms are readily released from MgH2 using much less energy and thus are more available to react with Ni once the dehydrogenation of MgH2 occurs, as compared to normal Mg.

  7. Thirteen Week Oral (Diet) Toxicity Study of Trinitrotoluene (TNT), Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) and TNT/RDX Mixtures in the Fischer 344 Rat


    lesions graded as minimal to mild were characterized by a diminution of spermatozoa , spermatids, and spermato- cytes as a result of degeneration and...revealed dose-dependent degeneration of the germinal epithelium of the seminiferous tubules with little or no mature spermatozoa present. At the TNT 300 mg...a a N- to NR N - N t * ga N Ifl to .4 r4 aý an a IC40 N x e W. H 0% t tO (l C4 P c- N Il WH4 En N% t Q QL Zn ta n to NQ in ei Io 4. . >4l 𔃾i 0 -4 e

  8. Thermodynamic modeling of the La-Mg-Y system and Mg-based alloys database

    DU Zhenmin; GUO Cuiping; LI Changrong; ZHANG Weijing


    As an example of the La-Mg-Y system, the method how to set up the thermodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases (liquid, body-centered cubic,face-centered cubic, hexagonal close-packed and double hexagonal close-packed) were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41La5, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae (Mg, Y)2(La,Mg, Y), Mg24(La,Mg, Y)4Y, Mg12(La, Y), Mg17(La, Y)2,Mg41(La,Y)5, Mg3(La,Mg,Y) and Mg2(La,Y), respectively. A model (La,Mg,Y)0.5(La,Mg,Y)0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution (A2) and MgM with CsCl-type structure (B2) in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.

  9. Lipid peroxidation in the kidney of rats treated with V and/or Mg in drinking water.

    Scibior, Agnieszka; Zaporowska, Halina; Niedźwiecka, Irmina


    LPO induced by in vitro treatment of kidney supernatants with exogenous Fe or V or Mg (600, 800 and 1000 microm) were a consequence of independent action of those metals and they also resulted from the interactions between exogenous Fe (Fe(exog)) and endogenous V (V(end)) and between V(end) and exogenous V (V(exog)). In conclusion, V (as NaVO(3)) consumed by the rats with drinking water at a dose of 12.9 mg V kg(-1) b.w. per 24 h for 12 weeks increased the basal LPO and markedly enhanced TAS in the renal tissue. Its pro-oxidant potential was also found in in vitro conditions. The Mg dose (6 mg Mg kg(-1) b.w. per 24 h) ingested by the rats together with V (12.7 mg V kg(-1) b.w. per 24 h) neither reduced nor intensified the spontaneous LPO, compared with V-only intoxicated animals; however, the stimulating effect of Mg on LPO was revealed in in vitro conditions.

  10. Solubility of RDX in Melting DNAN/MNA%RDX在2,4-二硝基苯甲醚(DNAN)低共熔体系中的溶解度

    罗观; 黄辉; 张帅; 王平胜; 蔡忠展; 张勇


    采用液相色谱法,在87 ~95.3℃温度范围内,测定了RDX在2,4-二硝基苯甲醚(DNAN)与N-甲基-4-硝基苯胺(MNA)低共熔体系中的溶解度.优化了色谱分离条件:流动相甲醇/水=6/4(V/V),流速为1.0 mL·min-1;检测波长254 nm,进样量5.D μL.实验考察了不同粒径的RDX、平衡时间以及温度对溶解度的影响,在低共熔物体系DNAN/MNA中,建立了RDX溶解度-温度关系曲线.结果表明,RDX在共熔体系中溶解度范围为9.39~10.28 g,并随着体系温度的升高而增大.%High performance liquid chromatography (HPLC) was employed to analysis the solubility of RDX in melting DNAN/MNA at the range of 87 ℃ to 95.3 °C. The optimal chromatography conditions were as following: mobile phase is methanol/water =6/4 ( V/V) , and flow rate I.0 mL-min-1, and wavelength of detector 254 nm, and injection volume 5.0 ΜL. The influence of particle size, equilibration time and temperature programming on solubility was studied. Under the optimum condition, the curve of the solubility of RDX in DNAN/MNA as a function of temperature was built. Results show that the solubility of RDX increases with increasing of the temperature.

  11. 直接法制备黑索今的工艺优化及安全实验%Process optimization and safety tests of RDX preparation by direct nitration

    李静; 陈丽珍; 王建龙; 兰贯超; 侯欢; 李满


    The impacts of nitrification temperature and mature temperature to RDX preparation by direct nitration were discussed.Within the scope of economy and security,the results showed that nitrification temperature at 0 ℃ and mature temperature at 30 ℃ that the average yield of RDX reached 79.01%through stability experiments under this optimum condition was the highest.Through the study of the sta-bility of RDX synthesis,it indicated that mature temperature at 30 ℃ for the nitration process was safe and reliable beyond that the nitrification liquid of low temperature entered into high temperature was sta-ble during the modified process.%主要探讨了硝化温度与成熟温度对直接法硝解乌洛托品制备黑索今的影响。在经济安全的考察范围内,结果表明,硝化温度在0℃,成熟温度在30℃时,黑索今的得率最高,为79.01%。通过对黑索今制备工艺过程的安定性实验考察,表明成熟期温度在30℃,对于硝化工序是安全可靠的,在工艺改进过程中低温硝化进入高温成熟是安定的。

  12. 近红外在线检测硝胺推进剂主要固体组分含量%Real-time detection of the main solid components concentration in RDX-CMDB with NIR spectral analysis

    邹权; 邓国栋; 郭效德; 姜炜; 宋丹; 李凤生


    This study focuses on the feasibility of real-time detecting the main solid components concentration of composite modified double base propellant containing RDX (RDX-CMDB). A batch of liquid mixtures including RDX,NC and water were prepared at laboratory, which were scanned directly with a fiber-optical probe of FT-NIR spectrophotometer on condition of stirring constantly. Two quantitative calibration models were constructed based on partial least squares regression for RDX and NC. Their correlation coefficient (R) is 0.997 1 and 0.989 5,and root mean square error of predicted (RMSEP) is 0.096 8 and 0. 1ll 0 respectively, which proves that the calibration models is accurate. It only took less than 30 seconds from scanning samples to obtaining result when calibration models have been generated. The results show that it is feasible to apply NIR analysis to on-line detection of the main solid constituents in CMDB.%研究了近红外方法对硝胺推进剂主要固体组分含量进行在线检测的可行性.参照吸收药制备过程的搅拌分散条件,配制黑索金、硝化棉和水的混合体系并用光纤探头直接采集近红外光谱,以偏最小二乘法分别对黑索金、硝化棉建立定量校正模型,模型相关系数R分别为0.9971、0.9895;预测标准偏差RMSEP分别为0.0968、0.1110.运用上述模型对单个样品进行检测,从光谱采集到得出结果耗时小于30 s.实验表明,近红外方法快速、准确,具备在线检测硝胺推进剂主要固体组分含量的可行性.

  13. Preparation and Hydrogen Storage Properties of Mg-Rich Mg-Ni Ultrafine Particles

    Jianxin Zou


    Full Text Available In the present work, Mg-rich Mg-Ni ultrafine powders were prepared through an arc plasma method. The phase components, microstructure, and hydrogen storage properties of the powders were carefully investigated. It is found that Mg2Ni and MgNi2 could be obtained directly from the vapor state reactions between Mg and Ni, depending on the local vapor content in the reaction chamber. A nanostructured MgH2 + Mg2NiH4 hydrogen storage composite could be generated after hydrogenation of the Mg-Ni ultrafine powders. After dehydrogenation, MgH2 and Mg2NiH4 decomposed into nanograined Mg and Mg2Ni, respectively. Thermogravimetry/differential scanning calorimetry (TG/DSC analyses showed that Mg2NiH4 phase may play a catalytic role in the dehydriding process of the hydrogenated Mg ultrafine particles.

  14. Ab initio Quantum Chemical Reaction Kinetics: Recent Applications in Combustion Chemistry (Briefing Charts)


    HMX RDX  Recent Works  See Geith et al...Propellants, Explosives, Pyrotechnics, 29, 3 (2004)  ∆Hcomb(DNB) = (5195 ± 300) kJ kg-1 (bomb calorimetry and MP2/cc-pVTZ ∆Hf) cf HMX 9435 & RDX 9560  Vd = 8660 ms-1, cf HMX 9100 & RDX 8750 ms-1  See Geith et al., Combust and Flame, 139, 358 (2004)  Recent synthesis (known since 1898 by

  15. Highly (100) oriented MgO growth on thin Mg layer in MTJ structure

    Jimbo, K [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1-S3-42 O-okayama, Meguro, Tokyo 152-8552 (Japan); Nakagawa, S, E-mail:


    In order to apply Stress Assisted Magnetization Reversal (SAMR) method to perpendicular magnetoresistive random access memory (p-MRAM) with magnetic tunnel junction (MTJ) using MgO (001) oriented barrier layer, multilayer of Ta/ Terfenol-D/ Mg/ MgO and Ta/ Terfenol-D/ MgO were prepared. While the MgO layer, deposited directly on the Terfenol-D layer, did not show (100) orientatin, very thin metallic Mg layer, deposited prior to the MgO deposition, was effective to attain MgO (100) orientation. The crystalline orientation was very weak without Mg, however, the multilayer with Mg showed very strong MgO(100) peak and the MgO orientation was shifted depending on the Mg thickness.

  16. Fabrication and superconducting properties of internal Mg diffusion processed MgB2 wires using MgB4 precursors

    Xu, Da; Wang, Dongliang; Yao, Chao; Zhang, Xianping; Ma, Yanwei; Oguro, Hidetoshi; Awaji, Satoshi; Watanabe, Kazuo


    Monofilament MgB2/Nb/Monel wires were fabricated using three different MgB4 precursors by an internal Mg diffusion (IMD) process. The wire geometry and heat-treatment conditions were optimized in order to improve the critical current density (J c) of the MgB2 wire. The influences of the quality of MgB4 powders, such as the particle size and MgO impurity, on the microstructure and superconducting properties of the wires were discussed. Although there were small amounts of voids, unreacted MgB4 particles and MgO impurity existed in the superconducting layers, and the transport layer J c of the wire with the MgB4 precursor reached 3.0 × 104 A cm-2 at 4.2 K and 10 T, which was comparable to that of IMD-processed wires fabricated using boron precursors. Both the non-barrier J c and engineering J c of MgB2 wire made using a MgB4 precursor were enhanced due to the improved grain connectivity and the enlarged fill factor.

  17. Determination of the 36Mg(n ,γ )37Mg reaction rate from Coulomb dissociation of 37Mg

    Shubhchintak; Chatterjee, R.; Shyam, R.


    We use the Coulomb dissociation (CD) method to calculate the rate of the 36Mg(n ,γ )37Mg radiative capture reaction. The CD cross sections of the 37Mg nucleus on a 208Pb target at the beam energy of 244 MeV/nucleon, for which new experimental data have recently become available, were calculated within the framework of a finite-range distorted-wave Born approximation theory that is extended to include the projectile deformation effects. Invoking the principle of detailed balance, these cross sections are used to determine the excitation function and subsequently the rate of the 36Mg(n ,γ )37Mg reaction. We compare these rates to those of the 36Mg(α ,n )39Si reaction calculated within a Hauser-Feshbach model. We find that for T9 as large as up to 1.0 (in units of 109 K) the 36Mg(n ,γ )37Mg reaction is much faster than the 36Mg(α ,n )39Si one. The inclusion of the effects of 37Mg projectile deformation in the breakup calculations enhances the (n ,γ ) reaction rate even further. Therefore, it is highly unlikely that the (n ,γ )β -decay r -process flow will be broken at the 36Mg isotope by the α process.

  18. The coordination of Mg in foraminiferal calcite

    Branson, Oscar; Redfern, Simon A. T.; Tyliszczak, Tolek; Sadekov, Aleksey; Langer, Gerald; Kimoto, Katsunori; Elderfield, Henry


    The Mg/Ca ratio of foraminiferal calcite is a widely accepted and applied empirical proxy for ocean temperature. The analysis of foraminifera preserved in ocean sediments has been instrumental in developing our understanding of global climate, but the mechanisms behind the proxy are largely unknown. Analogies have been drawn to the inorganic precipitation of calcite, where the endothermic substitution of Mg for Ca is favoured at higher temperatures. However, evidence suggests that foraminiferal Mg incorporation may be more complex: foraminiferal magnesium is highly heterogeneous at the sub-micron scale, and high Mg areas coincide with elevated concentrations of organic molecules, Na, S and other trace elements. Fundamentally, the incorporation mode of Mg in foraminifera is unknown. Here we show that Mg is uniformly substituted for Ca within the calcite mineral lattice. The consistency of Mg-specific X-ray spectra gathered from nano-scale regions across the shell (‘test’) reveals that the coordination of Mg is uniform. The similarity of these spectra to that produced by dolomite shows that Mg is present in an octahedral coordination, ideally substituted for Ca in a calcite crystal structure. This demonstrates that Mg is heterogeneous in concentration, but not in structure. The degree of this uniformity implies the action of a continuous Mg incorporation mechanism, and therefore calcification mechanism, across these compositional bands in foraminifera. This constitutes a fundamental step towards a mechanistic understanding of foraminiferal calcification processes and the incorporation of calcite-bound palaeoenvironment proxies, such as Mg.

  19. Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

    Tang, Jia-Jun; Yang, Xiao-Bao; Chen, Li-Juan; Zhao, Yu-Jun


    We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg(10bar 10)/MgH2(210), Mg(0001)/MgH2(101) and Mg(10bar 10)/MgH2(101), and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001)/MgH2(101) which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

  20. Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

    Jia-Jun Tang


    Full Text Available We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg(101¯0/MgH2(210, Mg(0001/MgH2(101 and Mg(101¯0/MgH2(101, and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001/MgH2(101 which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

  1. Mechanical Reinforcement on the Melt-cast Explosive of RDX/TNT by Chopped Fibers%短切纤维对RDX/TNT熔铸炸药的力学改性

    郑保辉; 王平胜; 罗观; 黄勇


    Using glass,polyester, aluminum and carbon fiber as the mechanical modifier of melt-cast explosive RDX/TNT 65/35, the influence of type, content and length on its mechanical property was studied through compressive and tensile experiments. Results show that, the modified effect on compressive strength with polyester fiber is the best, and the compressive strength of the explosive with 0.4% increases to 27.94 MPa.The tensile strength and tensile elongation decreases obviously with decrease of aluminum fiber.The tensile and compressive mechanical properties are degraded when using 0.2% glass fiber than that without fiber.The compressive mechanical performance of RDX/TNT 65/35 increase with the additive amount of glass fiber increase. With 0.01%and 0.05%carbon fiber separately, the tensile mechanical property with 3 mm carbon fiber is better than that with 6 mm carbon fiber, and tensile mechanical properties reach maximum using 0.05%3 mm carbon fiber.%采用玻璃纤维、聚酯纤维、铝纤维、碳纤维4种短切纤维作熔铸炸药力学性能改性剂,研究了压缩、拉伸力学实验中短切纤维的种类、添加量和长度对RDX/TNT 65/35熔铸炸药力学性能的影响。结果表明,聚酯纤维对压缩强度的改善效果最佳,添加量为0.4%时压缩强度达27.94 MPa。铝纤维会显著降低炸药的拉伸强度和拉伸延伸率。玻璃纤维添加量为0.2%时拉伸、压缩力学性能均低于不掺杂纤维材料的RDX/TNT 65/35熔铸炸药。添加量在0.2%~1.0%时,65/35-RDX/TNT的压缩力学性能随玻璃纤维用量的增加而升高。添加量分别为0.01%和0.05%时,使用3 mm碳纤维的炸药拉伸力学性能好于使用6 mm碳纤维,掺杂0.05%3 mm碳纤维的炸药各项拉伸力学性能最好。

  2. 含RDX的叠氮硝胺发射药热分解与燃烧性能%Thermal Decomposition and Combustion Performance of Azidonitramine Gun Propellant Containing RDX

    杨建兴; 贾永杰; 刘毅; 李乃勤; 白微; 张步允


    The thermal decomposition and combustion performance of homogeneous azidonitramine gun propellant composed of nitrocellulose,azidonitramine and nitroglycerine( DA3), azidonitramine gun propellant composed of 85 mass % of DA3 and 15 mass % of RDX( DAR15) and azidonitramine gun propellant composed of 75 mass % of DA3 and 25 mass % of RDX( DAR25) were studied by high-pressure DSC (PDSC) and a closed-bomb. The results show that the DSC curves of DAR15 and DAR2S consist of two exothermic peaks, whereas DA3 gives only one exothermic peak. The first exothermic peaks at 210 t is due to the thermal decomposition of DA3. The second exothermic peaks at 236 t is caused by the decomposition of RDX. With increasing the RDX content, the first exothermic quantity decreases, and the second exothermic quantity increases. In comparison with DA3 , the burning rate pressure exponent of DAR15 and DAR25 increases over the pressure range from 40 Mpa to 120 Mpa and decreases over the pressure range from 120 Mpa to the pressure corresponding with maximum dp/dt (pdpm). RDX makes the initial burning rate and combustion gas generation brisance of DAR15 and DAR25 decrease, and their burning progressivity increases.%用高压差示扫描量热法(DSC)与密闭爆发器实验,对比研究了均质叠氮硝胺发射药(DA3),和含DA3、RDX质量分数分别为85%、15%的DAR15发射药及含DA3、RDX质量分数分别为75%、25%的DAR25发射药的热分解及燃烧性能.结果表明,DAR15及DAR25发射药的DSC有两个放热峰,峰值温度约为210℃第一个放热峰由DA3分解所致,峰值温度约为236℃的第二个放热峰由RDX的分解引起,而DA3仅呈现一个放热峰.随着RDX含量增加,第一个峰的放热量减少,第二个峰的放热量增加.与DA3相比,DAR15及DAR25在40~120 MPa压力范围内燃速压力指数变大,在120 MPa~Pd.m(压力陡度的最大值所对应压力)压力范围内燃速压力指数降低.RDX的引入使DAR15及DAR25发射药的起

  3. Análise de crescimento em Heteranthera reniformis, sob diferentes teores de Ca, Mg e S Growth analysis in Heteranthera reniformis under different contents of Ca, Mg and S

    Vanessa David Domingos


    Full Text Available O objetivo deste trabalho foi estudar o crescimento, alocação de biomassa e teores de nutrientes em Heteranthera reniformis Ruiz & Pav., sob o efeito de diferentes concentrações de Ca, Mg e S. As plantas foram cultivadas em vasos plásticos preenchidos com pedra rolada, em soluções nutritivas a 80% da concentração original de Sarruge, correspondente à solução-base. O experimento foi desenvolvido em delineamento experimental inteiramente casualizado, com quatro teores (0%, 25%, 50% e 75% da solução base de 80% avaliados em Ca, Mg e S, além da testemunha (solução-base, com quatro repetições no período de 35 dias em casa de vegetação. O aumento dos teores de Ca na solução propiciou uma redução significativa na área foliar. As maiores áreas foliares ocorreram em soluções a 25% de Ca e 50% de Mg e S. A maior proporção de biomassa seca está no caule, exceto a 25% de Ca (40 mg L-1 que propiciou maior área foliar e área foliar específica. Entre os teores de Mg na solução, as maiores biomassas foram observadas a 50% de Mg (19,2 mg.L-1 e, para o S, não houve diferenças significativas, exceto a 0%. A solução com 160 mg L-1 de Ca propiciou maior concentração de Ca na folha (56,6 g kg-1. Os teores de Ca, Mg e S em solução corresponderam a um aumento proporcional na planta. Os teores de enxofre nas folhas e nos caules aumentaram com a concentração de S na solução, enquanto o teor nas raízes reduziu nas concentrações entre 12,8 e 38,4 mg.L-1.The objective was to study the growth, biomass allocation and concentration of nutrients in Heteranthera reniformis Ruiz & Pav. under the effect of different concentrations of Ca, Mg and S. The plants were cultivated in plastic pots fulfilled with rolled stone, in nutrient solutions of 80% of the original concentration of Sarruge. The experiment was carried out in a complete randomized design, with 4 contents (0, 25, 50 and 75% of the base solution evaluated in Ca, Mg and

  4. Corrosion behavior of Mg and Mg-Zn alloys in simulated body fluid

    GAO Jia-cheng; WU Sha; QIAO Li-ying; WANG Yong


    The corrosion behavior of Mg and Mg-Zn in simulated body fluid was studied.The mass loss of pure Mg,Mg-Zn-Zr and Mg-Zn-Zr-Y in simulated body fluid was measured using photovoltaic scale meter.Corrosion rate was determined through electrochemical tests.Finally,the corrosion mechanism was tbermodynamically studied.The results show that the corrosion rate decreases with the lapse of time for both pure Mg and Mg alloys.The purer the alloy,the borer the corrosion resistance exhibits.The corrosion behavior of Mg alloy is improved by the addition of trace Y.

  5. Non-resonant microwave absorption studies of superconducting MgB2 and MgB2 + MgO

    Janhavi P Joshi; Subhasis Sarangi; A K Sood; Dilip Pal; S V Bhat


    Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing ∼ 10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field c1 is observed indicating a non- wave superconductivity. However, the phase reversal of the NRMA signal which could suggest wave symmetry is also not observed. In the MgB2 + MgO sample, much larger low field dependent absorption is observed indicating the presence of intergranular weak links. The hysteretic behavior of NRMA is compared and contrasted in the two samples. In the pure MgB2 sample, a large hysteresis is observed between the forward and the reverse scans of the magnetic field indicating strong pinning of flux lines. This hysteresis saturates a few degrees below c while in the MgB2 + MgO sample, a much slower increase of hysteresis with decreasing temperature is observed, a signature of weaker pinning.

  6. The conduction bands of MgO, MgS and HfO2

    Boer, P.K. de; Groot, R.A. de


    Electronic structure calculations for MgO, MgS and HfO2 are reported. It is shown that the conduction bands of MgO and MgS have predominantly anion character, contrary to the common picture of the conduction band being derived from cation states. In transition metal oxides, unoccupied anion states a

  7. TRPM6 forms the Mg2+ influx channel involved in intestinal and renal Mg2+ absorption.

    Voets, T.; Nilius, B.; Hoefs, S.J.G.; Kemp, J.W.C.M. van der; Droogmans, G.; Bindels, R.J.M.; Hoenderop, J.G.J.


    Mg2+ is an essential ion involved in a multitude of physiological and biochemical processes and a major constituent of bone tissue. Mg2+ homeostasis in mammals depends on the equilibrium between intestinal Mg2+ absorption and renal Mg2+ excretion, but little is known about the molecular nature of

  8. Hydrogen storage systems from waste Mg alloys

    Pistidda, C.; Bergemann, N.; Wurr, J.; Rzeszutek, A.; Møller, K. T.; Hansen, B. R. S.; Garroni, S.; Horstmann, C.; Milanese, C.; Girella, A.; Metz, O.; Taube, K.; Jensen, T. R.; Thomas, D.; Liermann, H. P.; Klassen, T.; Dornheim, M.


    The production cost of materials for hydrogen storage is one of the major issues to be addressed in order to consider them suitable for large scale applications. In the last decades several authors reported on the hydrogen sorption properties of Mg and Mg-based systems. In this work magnesium industrial wastes of AZ91 alloy and Mg-10 wt.% Gd alloy are used for the production of hydrogen storage materials. The hydrogen sorption properties of the alloys were investigated by means of volumetric technique, in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and calorimetric methods. The measured reversible hydrogen storage capacity for the alloys AZ91 and Mg-10 wt.% Gd are 4.2 and 5.8 wt.%, respectively. For the Mg-10 wt.% Gd alloy, the hydrogenated product was also successfully used as starting reactant for the synthesis of Mg(NH2)2 and as MgH2 substitute in the Reactive Hydride Composite (RHC) 2LiBH4 + MgH2. The results of this work demonstrate the concrete possibility to use Mg alloy wastes for hydrogen storage purposes.

  9. Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg2Si/MgB2 nanocomposites

    Ueno, Katsuya; Nagashima, Yukihito; Seto, Yusuke; Matsumoto, Megumi; Sakurai, Takahiro; Ohta, Hitoshi; Takahashi, Kazuyuki; Uchino, Takashi


    Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg2Si)/superconductor(MgB2) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg2Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB2 nanograins surrounded by the MgO/Mg2Si matrix. This transition is followed by the intergrain phase-lock transition at ˜24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a simple process to fabricate dense nanocomposites with high-quality interfaces, but also enables to investigate the electric and magnetic properties of embedded superconducting nanograins with good intergrain coupling.

  10. The Coordination of Mg in Foraminiferal Calcite

    Branson, O.; Redfern, S. A.; Tyliszczak, T.; Sadekov, A.; Langer, G.; Elderfield, H.


    The Mg/Ca ratio in calcite shells ('tests') of foraminifera is an empirical ocean temperature proxy widely used to interpret palaeoclimates. We explore the distribution and local environment of Mg in foram tests using STXM and NEXAFS spectroscopy to test the fundamental assumptions behind the proxy, and shed light on the mechanisms underpinning this vital oceanographic tool. Throughout the development of the Mg/Ca proxy, it has been assumed that Mg in foraminifera tests substitutes directly into the calcite lattice (1). This assumption is based on XRD analyses of various high-Mg biogenic carbonates, where Mg concentrations are manifest in the shifted position of diffraction peaks (2, 3). The extrapolation of this trend to foraminiferal calcite links the proxy to inorganic precipitation experiments, and provides a theoretical mechanistic framework to understand the link between Mg/Ca and temperature: the substitution of Mg is endothermic, and favoured at higher temperatures. However, the concentration of Mg in most foraminifera (0-10 mmol/mol Mg/Ca) is below the detection limit of XRD methods, and the analogy to inorganic systems has not been explicitly tested. Electron microprobe (4-6), LA-ICP-MS (7) and high-resolution nanoSIMS mapping (Sadekov, unpub.) of foraminifera tests have revealed the presence of high 'trace element' bands running in plane with the test surface, enriched in Mg, Sr, S, organic molecules and other trace elements. This emphasises a key question highlighted by Dodd (1) when the proxy was still in its infancy: how is Mg incorporated into mineral skeletons? By direct substitution into the calcite lattice, interstitially in a separate distinct mineral phase, or associated with organic compounds? We address this fundamental question using scanning transmission X-ray microscopy (STXM) and X-ray absorption spectroscopy at ALS beamline 11.0.2 to examine the distribution and local atomic environment of Mg in two contrasting species of foraminifera

  11. Existing form and effect of zirconium in pure Mg, Mg-Yb, and Mg-Zn-Yb alloys

    YU Wenbin; HE Hong; LI Chunmei; LI Qing; LIU Zhiyi; QIN Bing


    The existing form and grain refining effects of small zirconium addition in pure Mg, Mg-Yb and Mg-Zn binary alloys, and Mg-Zn-Yb ternary alloy (ZK60-Yb) were investigated. The results show that Zr element exists mainly in single and cluster particles of pure α-Zr or Zn-Zr compounds inside grains and at grain boundaries. Only the particles located in the interior of grains can act as the nucleus for α-Mg growth and effectively promote the formation of Fine equiaxed grains. The broken and dispersed Zr-rich particles produced during the hot extrusion process can form nebulous banded structure in which these free particles may act as obstacles to dislocation motion in wrought magnesium alloys.

  12. Melatonin administration in diabetes: regulation of plasma Cr, V, and Mg in young male Zucker diabetic fatty rats.

    Navarro-Alarcon, Miguel; Ruiz-Ojeda, Francisco J; Blanca-Herrera, Rosa M; Kaki, Abdullah; Adem, Abdu; Agil, Ahmad


    The use of melatonin, a neurohormone present in plants, represents an exciting approach for the maintenance of optimum health conditions. Melatonin administration ameliorates glucose homeostasis in Zucker diabetic fatty (ZDF) rats. The objective of this study was to investigate the effects of melatonin in diabetes in relation to the levels and regulation of plasma chromium (Cr), vanadium (V), and magnesium (Mg) in Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats. At the age of 6 weeks, ZDF (n = 30) and ZL (n = 30) groups were each subdivided into three groups: control (C) (n = 10), vehicle-treated (V') (n = 10) and melatonin-treated (M) (10 mg kg(-1) per day; n = 10) groups for a 6 week period. After treatment, plasma mineral concentrations were measured by flame (Mg) and electrothermal (Cr and V) atomic absorption spectrometry. No significant differences were found between the C and V' groups (p > 0.05). Plasma Mg levels were significantly lower in C-ZDF vs. C-ZL rats, demonstrating the presence of hypomagnesemia in this diabetes mellitus model. Plasma V and Cr levels were significantly higher in M-ZDF vs. C-ZDF rats. Plasma Mg levels in ZDF rats were not affected by melatonin treatment (p > 0.05). Melatonin administration ameliorates the diabetic status of ZDF rats by enhancing plasma Cr and V concentrations. This appears to be the first report of a beneficial effect of melatonin treatment on plasma Cr and V regulation in ZDF rats.

  13. Theoretical simulation of CO2 capture by an \\text{A}{{\\text{l}}_{11}}\\text{Mg}_{3}^{-} cluster

    Jiang, Yuanyuan; Xie, Xuefang; Hamid, Ilyar; Chen, Chu; Duan, Haiming


    In order to have an impact on carbon emissions, new stable materials for carbon capture should be able to adsorb CO2 from a mixture of other gases efficiently. Based on density functional theory calculations, we showed that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster has an excellent capture capacity of CO2 and high CO2 selectivity under ambient conditions. \\text{A}{{\\text{l}}11}\\text{Mg}3- has an O2-resist property because this cluster is similar to \\text{Al}13- which contains 40 electrons with a larger energy gap. The \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster prefers to adsorb CO2 compared with CH4, H2 and N2, and the CO2 molecule can be chemically adsorbed on the cluster by overcoming a lower barrier, which originates from the introduction of the Mg atom. When seven CO2 molecules are chemically adsorbed on the cluster, the capture capacity of CO2 can reach up to 18.99 mol kg-1 this means that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster can be viewed as a potential candidate material for CO2 capture.

  14. UHV and Ambient Pressure XPS: Potentials for Mg, MgO, and Mg(OH)2 Surface Analysis

    Head, Ashley R.; Schnadt, Joachim


    The surface sensitivity of x-ray photoelectron spectroscopy (XPS) has positioned the technique as a routine analysis tool for chemical and electronic structure information. Samples ranging from ideal model systems to industrial materials can be analyzed. Instrumentational developments in the past two decades have popularized ambient pressure XPS, with pressures in the tens of mbar now commonplace. Here, we briefly review the technique, including a discussion of developments that allow data collection at higher pressures. We illustrate the information XPS can provide by using examples from the literature, including MgO studies. We hope to illustrate the possibilities of ambient pressure XPS to Mg, MgO, and Mg(OH)2 systems, both in fundamental and applied studies.

  15. Diffusion of Ca and Mg in Calcite

    Cygan, R.T.; Fisler, D.K.


    The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process.

  16. Treatment of patients with essential hypertension: amlodipine 5 mg/benazepril 20 mg compared with amlodipine 5 mg, benazepril 20 mg, and placebo.

    Kuschnir, E; Acuña, E; Sevilla, D; Vasquez, J; Bendersky, M; Resk, J; Glazer, R


    This multicenter, double-masked, randomized, parallel-group study compared the efficacy, tolerability, and safety of amlodipine 5 mg/benazepril 20 mg, amlodipine 5 mg, benazepril 20 mg, and placebo in patients with essential hypertension. After a placebo run-in period, 308 patients (all white) were randomized to treatment groups and took medication once daily for 8 weeks. Blood pressure was measured after 4 and 8 weeks of treatment in the 23- to 26-hour period after dosing. Patients wore a noninvasive blood pressure monitor for 24 hours before randomization and before the final visit. Investigators recorded adverse experiences at randomization and at study weeks 4 and 8, and obtained specimens for laboratory testing at randomization and at study week 8. Three hundred seven patients were evaluated for efficacy, and 308 for tolerability and safety. At end point (the last postrandomization measurement for each patient), the reduction in mean sitting diastolic blood pressure with the amlodipine 5 mg/benazepril 20 mg treatment was statistically significantly greater than with any comparative therapy. The results of 24-hour monitoring showed that the amlodipine/benazepril treatment, unlike monotherapy, maintained the hourly mean diastolic blood pressure at amlodipine 5 mg/benazepril 20 mg versus 67.5%, 53.3%, and 15.8% with amlodipine, benazepril, and placebo, respectively. This difference between the amlodipine/benazepril treatment group and each comparative single-agent treatment group was statistically significant. Drug-related adverse events occurred in 15.6% of patients in the amlodipine/benazepril group and in 24.7%, 6.5%, and 11.7% of patients in the amlodipine, benazepril, and placebo groups, respectively. Edema occurred less often in the amlodipine/benazepril group than in the amlodipine group. Overall, once-daily therapy with amlodipine 5 mg/benazepril 20 mg provided an antihypertensive effect that was statistically and clinically superior to amlodipine 5 mg

  17. Solvation of Mg in Helium-4: Are there Meta-stable Mg Dimers ?

    Krotscheck, Eckhard


    Experiments on the formation of magnesium complexes in $^4$He nanodroplets were interpreted as the observation of the formation of weakly bound magnesium complexes. We present results for single Mg and Mg dimer solvation using the hypernetted chain / Euler-Lagrange method as well as path integral Monte Carlo simulations. We find that the phonon-mediated, indirect Mg-Mg interaction adds an oscillatory component to the direct Mg-Mg interaction. We undertake a step-by-step examination of the ingredients of the calculation of the phonon-induced interaction, comparing the results of semi-analytic HNC-EL calculations for bulk and single impurity results with experiments as well as Monte Carlo data. We do not find evidence for a sufficiently strong secondary minimum in the effective Mg-Mg interaction to support a metastable state.

  18. The role of MgO content in ex situ MgB2 wires

    Kovac, P.; Hugek, I.; Meligek, T.;


    An experimental study of the effect of MgO content in the MgB2 powder used for ex situ made composite wires was carried out. Two single-core MgB2/Fe/Cu wires were made using commercial MgB2 powders from Alfa Aesar containing different fraction of MgO. Critical temperature and critical currents...... of as-deformed and heat-treated wires were measured. The differences between the wires are discussed and correlated with the MgO content. It was found that by increasing the amount of MgO, the inter-grain connectivity worsens, but well distributed and low size MgO particles improve flux pinning....

  19. Aging Behavior of Mg-Y-Zr and Mg-Nd-Zr Cast Alloys


    Aging behavior of Mg-3.6Y-0.5Zr and Mg-2.7Nd-0.5Zr alloys was investigated by microhardness measurement and transmission electron microscopy. In the case of Mg-Y-Zr alloy, the presence of β″ phase, a major strengthener, having base centered orthorhombic structure with its lattice constants of aβ″=0.64 nm, bβ″=2.22 nm,and cβ″=0.52 nm was identified. In the case of Mg-Nd-Zr alloy aged at 250℃, the presence ofβ″ and β′phases was identified. The crystal structure ofβ″ phase was found to be DO19 and its orientation relationships with Mg matrix were [0001]β″//[0001]Mg and [01-10]β″//[0110]Mg. The β′ phase had face centered cubicstructure and its orientation relationships with Mg matrix were [011]β′//[0001]Mg and [-11-1]β′//[-2110]Mg.The Mg-2.7Nd-0.5Zr alloy showed higher hardness compared with Mg-3.6Y-0.5Zr alloy.

  20. In vitro and in vivo comparison of binary Mg alloys and pure Mg.

    Myrissa, Anastasia; Agha, Nezha Ahmad; Lu, Yiyi; Martinelli, Elisabeth; Eichler, Johannes; Szakács, Gábor; Kleinhans, Claudia; Willumeit-Römer, Regine; Schäfer, Ute; Weinberg, Annelie-Martina


    Biodegradable materials are under investigation due to their promising properties for biomedical applications as implant material. In the present study, two binary magnesium (Mg) alloys (Mg2Ag and Mg10Gd) and pure Mg (99.99%) were used in order to compare the degradation performance of the materials in in vitro to in vivo conditions. In vitro analysis of cell distribution and viability was performed on discs of pure Mg, Mg2Ag and Mg10Gd. The results verified viable pre-osteoblast cells on all three alloys and no obvious toxic effect within the first two weeks. The degradation rates in in vitro and in vivo conditions (Sprague-Dawley® rats) showed that the degradation rates differ especially in the 1st week of the experiments. While in vitro Mg2Ag displayed the fastest degradation rate, in vivo, Mg10Gd revealed the highest degradation rate. After four weeks of in vitro immersion tests, the degradation rate of Mg2Ag was significantly reduced and approached the values of pure Mg and Mg10Gd. Interestingly, after 4 weeks the estimated in vitro degradation rates approximate in vivo values. Our systematic experiment indicates that a correlation between in vitro and in vivo observations still has some limitations that have to be considered in order to perform representative in vitro experiments that display the in vivo situation.

  1. The Mg impurity in nitride alloys

    Zvanut, M. E.; Willoughby, W. R.; Sunay, U. R. [Department of Physics, University of Alabama at Birmingham, Birmingham AL (United States); Koleske, D. D.; Allerman, A. A. [Sandia National Laboratory, Albuquerque NM (United States); Wang, Ke; Araki, Tsutomu [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga (Japan); Nanishi, Yasushi [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga, Japan and WCU Program, Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)


    Although several magnetic resonance studies address the Mg acceptor in GaN, there are few reports on Mg doping in the alloys, where hole production depends strongly on the Al or In content. Our electron paramagnetic resonance (EPR) measurements of the p-type alloys suggest that the Mg impurity retains the axial symmetry, characteristic of a p-type dopant in both alloys; however, In and Al produce additional, different characteristics of the acceptor. In InGaN, the behavior is consistent with a lowering of the acceptor level and increasing hole density as In concentration increases. For AlGaN, the amount of neutral Mg decreases with increasing Al content, which is attributed to different kinetics of hydrogen diffusion thought to occur in samples with higher Al mole fraction.

  2. Thermodynamic optimization of Mg-Nd system

    MENG Fan-gui; LIU Hua-shan; LIU Li-bin; JIN Zhan-peng


    Based on the reported experimental data, the phase diagram of Mg-Nd binary system was optimized using the CALPHAD approach. Gibbs energies of the disordered BCC_A2 and ordered BCC_B2 phases were modeled with a single expression based on a 2-sublattice model. Liquid and terminal solutions, such as dHCP and HCP, were modeled as substitutional solutions. Intermediate phases Mg2Nd, Mg3Nd and Mg41Nd5 were treated as stoichiometric compounds. The optimization was carried out in the Thermo-Calc package. A set of thermodynamic parameters is obtained. Calculated phase diagram, enthalpies of formation and Gibbs energies of formation are in reasonable agreement with the experimental data.

  3. MgH{sub 2} as dopant for improved activation of commercial Mg ingot

    Jain, P., E-mail: [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada); Lang, J. [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada); Skryabina, N.Y. [Department of Physics, Perm State University, 15, Bukireva, 614990 Perm (Russian Federation); Fruchart, D. [Institut Néel, BP 166, 38042 Grenoble Cedex 9 (France); Santos, S.F [CECS, Federal University of ABC, Rua Santa Adélia 166, Santo André, SP 09210-170 (Brazil); Binder, K.; Klassen, T. [Institute of Materials Technology, Helmut-Schmidt-University, University of the Federal Armed Forces, Holstenhofweg 85, 22043 Hamburg (Germany); Huot, J., E-mail: [Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-Rivières, Québec G9A 5H7 (Canada)


    Highlights: •We propose a simple method to reduce production cost of light weight materials for hydrogen storage applications. •Cheaper Mg ingot rather than expensive MgH{sub 2} is used as starting material. •Effect of MgH{sub 2} as catalytic powder for improved activation behavior of Mg is demonstrated. -- Abstract: In this paper, we propose a method to decrease the activation time (first hydrogenation) of commercial Mg. This new alternative processing route uses a combination of cold rolling and short time ball milling to obtain full hydrogen capacity quickly in the first hydrogenation. As ball milling of ductile materials leads to particle agglomeration, brittle Mg plates produced by repetitive cold rolling were used as starting material. These rolled plates were then ball milled for 30 min with and without the addition of 5 wt% Mg or MgH{sub 2} powders. All the synthesized samples were investigated for hydrogen storage, absorption–desorption behavior and microstructure using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and pressure-composition temperature (PCT) methods. Results showed slow activation behavior for cold rolled Mg plates, which was slightly improved after milling. Further improvement was obtained by adding 5 wt% of Mg powder during ball milling. In contrast, when the plates were ball milled with 5 wt% of MgH{sub 2} powder a drastic improvement in activation behavior was observed with hydrogen capacity reaching up to 6.2 wt% in comparison to 2.74 wt% for undoped and 3.57 wt% for Mg doped samples. These results reveal that ball milling with ductile Mg powder deforms only the surface of Mg plates while brittle MgH{sub 2} powders causes fracturing and cracks, increasing the surface area and generating heterogeneous nucleation sites within the bulk material.

  4. The influence of Mg-Zr master alloy microstructure on the corrosion of Mg

    Gandel, D. S.; Easton, M. A.; Gibson, M. A.; Abbott, T.; Birbilis, N.

    In this study, sixteen Mg-Zr alloys were produced to investigate the role of Zr on corrosion of Mg. Alloys were produced using two different commercial Mg-Zr master alloys commonly used for grain refining Mg, but which contain different Zr particle size distributions. It is seen that the master alloy with a smaller Zr particle size leads to an alloy containing more Zr in solid solution. The ratio of Zr in solid solution and in particle form was observed to have a marked effect on the corrosion of Mg.

  5. Features of Mg2Si Layer Growth in Si/Mg2Si Multilayers

    L.E. Konotopskyi


    Full Text Available Features of magnesium siliced layer growth in Si/Mg2Si multilayers in initial state and after thermal annealing were studied by methods of transmission electron microscopy and X-Ray scattering. As-deposited magnesium silicide layers are amorphous with nanocrystal inclusions of metastable h-Mg2Si. Formation of Mg2Si in hexagonal modification occurs under the influence of stress produced by silicon layers. At T = 723 К Mg2Si layers finished crystallizes in hexagonal modification, with some coarsening of grains. That is accompanied with 7.3 % reduction in period of the Si/Mg2Si multilayer.

  6. Influence of Mg Content on Deformability of AlMg Alloys during Extrusion

    Leśniak D.


    Full Text Available In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy’s border solidus and liquidus temperatures were also determined.

  7. Mammalian Toxicological Evaluation of RDX


    glucose, sodium, potassium and calcium electrolytes, blood urea nitrogen (BUN), and alkaline phosphatase. Clinical chemistries parameters were...were stored in 1% KOH for two days then stained with alizarin red. 5 After differential decolorization, the skeletons were examined by experi- enced...feeding dams commercially aged diphenylamine containing DPA- derived impurities. 1 2 Histologic study of the thymus revealed subtle changes in two and a

  8. Elevated temperature properties of Mg- 12Li-Al-MgO composites

    WEI Xiao-wei; HUANG Qing-min


    The compressive creep of Mg-12Li-Al-MgO particulate composites was investigated, which were produced by the reaction of reinforcement materials (B2O3) with Mg-12Li-Al alloy melt in the temperature range of 100-190 ℃ and under different compressive stress in the range of 40-70 MPa with special apparatus. The content of MgO particulates is about 0, 5%, 10%,15%(volume fraction) in Mg-12Li-Al alloy respectively. The results reveal that the creep resistance of the particulate composites is increased with increasing the content of MgO particulates and considerable improvementin creep resistance is observed in Mg-12Li-Al-MgO composites. However, over all range of temperatures and stresses, the creep data for these composites can be correlated using an empirical equation εs =Aσnexp(-Q/RT), where n is 4.93 and Q is about 78.1 kJ/mol for Mg-14Li-Al alloy and n is between 7.48 and 9.47 and Q is 111.2-137.3 kJ/mol for Mg-12Li-Al-MgO composites. The different compressive creep behavior of the composites is associated with the different material constant A. The compressive creep rate is controlled by the lattice diffusion of Li and dislocation climb.

  9. Ultrafast Synthesis and Related Phase Evolution of Mg2Si and Mg2Sn Compounds

    Zhang, Qiang; Lu, Qiangbing; Yan, Yonggao; Su, Xianli; Tang, Xinfeng


    Both Mg2Si and Mg2Sn compounds were synthesized by an ultra-fast self-propagating high-temperature synthesis (SHS) method. The data regarding SHS were obtained via theoretical calculation combined with experiments, showing that the adiabatic temperature T ad and ignition temperature T ig of Mg2Si are a little higher than those of Mg2Sn. The mechanism of phase evolution and the concomitant microstructure evolution during the synthesis process of Mg2Si and Mg2Sn compounds were investigated by adopting SHS technique coupled with a sudden quenching treatment. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and x-ray powder diffraction (XRD) results indicate that Mg2Si compound can be directly synthesized through the reaction of Mg and Si elements at around 850 K. Correspondingly, the formation of Mg2Sn needs to undergo melting of Sn and the subsequent feeble reaction between Mg and Sn elements before the large scale transformation at 730 K. As the groundwork, this research embodies great significance for future study on the ultrafast SHS process of the ternary Mg2Si1-x Sn x solid solutions.

  10. Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

    Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.


    An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

  11. Melting relations in the MgO-MgSiO3 system up to 70 GPa

    Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru


    Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).

  12. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

    Bonarowska, Magdalena; Wojciechowska, Maria; Zieliński, Maciej; Kiderys, Angelika; Zieliński, Michał; Winiarek, Piotr; Karpiński, Zbigniew


    Pd/MgO, Pd/MgF₂ and Pd/MgO-MgF₂ catalysts were investigated in the reaction of CCl₄ hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF₂-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C₂-C₅ hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF₂ is beneficial for shaping high activity of palladium catalysts. The MgO-MgF₂ support characterized by stronger Lewis acidity than MgF₂ contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  13. N2 O5/HNO3硝解乌洛托品制备 RDX 的机理%The Mechanism for the Preparation of RDX from the Nitrolysis of Hexamethylenetetramine with N2 O5/HNO3

    王志鑫; 杨红伟; 伍波; 吕春绪; 程广斌


    The reaction mechanism for the nitrolysis of hexamethylenetetramine (HA)in the nitrating system of N2 O5/HNO3 and N2 O5/HNO3/CH2 Cl2 was monitored by using 13 C NMR spectroscopy.Based on the analytical result of the 13 C NMR spectrum,and combined the result of calculated 13 C NMR of the possible intermediates and by-products in the nitrolysis reaction process of HA,the structures of the possible intermediates and by-products in the nitrolysis reaction process of HA were presented.A possible mechanism for the nitrolysis of HA in the nitrating system of N2 O5/HNO3 was speculated.In the first step,hexamethylenetetramine dinitrate (HADN)was formed via one molecular HA and two molecular HNO3 .And then,HADN gradually degrades to RDX via cyclotrimethylen enitramine matrix.%利用13 C NMR 谱监测了乌洛托品(HA)在 N2 O5/HNO3和 N2 O5/HNO3/CH2 Cl2硝化体系中硝解反应的历程,根据实验13 C NMR 谱和计算13 C NMR 谱的解析结果,并结合 HA 硝解反应过程中可能存在中间体和副产物的13 CNMR 理论计算结果,提出了硝解历程中可能存在的中间体与副产物的结构,推测了 HA 在 N2 O5/HNO3体系中的硝解历程为:HA 首先与两分子 HNO3结合生成乌洛托品二硝酸盐(HADN);HADN 再经环三亚甲基硝胺母体逐步降解为黑索今(RDX)。

  14. Preparation of Metallic Isotope 26Mg

    WuXiaolei; ZhangFuming; GanZaiguo; GuoJunsheng; QinZhi


    Some special isotope material is usually used in nuclear experiments. It can be served as ion beam or target. When new superheavy nuclide 265Bh (Z=107) is synthesized, a reaction of 243Am target with 26Mg ion beamis selected to produce new isotope 265Bh. The preparation and production of this rare and extremely expensive isotope 26 Mg used for ion beam substance will be a key problem in synthesizing experiment of 265Bh. Theavailable chemical form of isotope 26Mg in commercial product usually is oxide or other compound, which are not required in our experiment. They need to be transformed to metal form as a proper working substance in ion source.

  15. Hydrogenation properties of Mg-Al alloys

    Andreasen, Anders


    In this paper the properties of Mg-Al alloys in relation to hydrogen storage are reviewed. The main topics of this paper are materials preparation, hydrogen capacity, thermodynamics of hydride formation, and the kinetics of hydride formation and decomposition. Hydrogenation of Mg-Al leads...... to disproportionation with the formation of magnesium hydride and metallic aluminum as the final product. Experimental evidence renders this process reversible. It is observed that the enthalpy of hydride formation of magnesium is lowered upon alloying with Al due to a slightly endothermic disproportionation reaction....... Further, it is found that the kinetics of hydrogenation, as well dehydrogenation, may be significantly improved by alloying compared to pure Mg. The expense of these improvements of the hydrogenation/dehydrogenation properties is a lower gravimetric hydrogen density in the hydrogenated product, (C) 2008...

  16. High Spin States in ^24Mg

    Schwartz, J.; Lister, C. J.; Wuosmaa, A.; Betts, R. R.; Blumenthal, D.; Carpenter, M. P.; Davids, C. N.; Fischer, S. M.; Hackman, G.; Janssens, R. V. F.


    The ^12C(^16O,α)^24Mg reaction was used at 51.5MeV to populate high angular momentum states in ^24Mg. Gamma-rays de-exciting high spin states were detected in a 20 detector spectrometer (the AYE-ball) triggered by the ANL Fragment Mass Analyser (FMA). Channel selection, through detection of ^24Mg nuclei with the appropriate time of flight, was excellent. All the known decays from high spin states were seen in a few hours, with the exception of the 5.04 MeV γ-decay of the J^π=9^- state at 16.904 MeV footnote A.E.Smith et al., Phys. Lett. \\underlineB176, (1986)292. which could not be confirmed. The potential of the technique for studying the radiative decay of states with very high spin in light nuclei will be discussed.

  17. Phase equilibrium in Mg-Cu-Y

    Mezbahul-Islam, Mohammad; Medraj, Mamoun


    Magnesium-based bulk metallic glasses (BMG) have potential in applications ranging from biomedical to sports equipment and the Mg-Cu-Y system offers some of the most promising alloys. Phase relations and ternary solubility of the binary and ternary compounds of this system have been experimentally investigated. The Isothermal section of Mg-Cu-Y system at 673 K for the entire composition range has been constructed. Phase relations in the Cu-rich (>66 at.% Cu) region of the Mg-Cu-Y system has been determined for the first time. The homogeneity range of three ternary compounds has been determined. Solidifications behavior of several key alloys have been discussed based on the differential scanning calorimetry (DSC) experiments and thermodynamic calculations. Extensive analysis of the DSC curves has been carried out to relate them to the corresponding phase transformation reactions and temperatures. Some of the most promising metallic glass forming regions have been analyzed using thermodynamic calculations.

  18. Superconductivity in MgB2


    In January of 2001 the superconductivity of the compound MgB2 with a critical temperature Tc of up to 39 K was discovered. This Tc is the highest in all intermetallic compound and alloy superconductors. MgB2 has a simple structure and its manufacturing capital cost is lower, therefore it could become a practical superconductor in the future. The recent progress is reviewed here which covers the progress in electronic structure, high Tc mechanism, superconducting parameters (Debye temperature, specific heat coefficient of electron, critical fields, coherent length, penetration depth, energy gap, critical current and relaxation rate of flux). Moreover the issue on power transmission is discussed.

  19. Electron microscopy observations of MgB 2 wire prepared by an internal Mg diffusion method

    Shimada, Y.; Kubota, Y.; Hata, S.; Ikeda, K.; Nakashima, H.; Matsumoto, A.; Togano, K.; Kumakura, H.


    Microstructure in a high-density MgB2 wire fabricated by an internal Mg diffusion (IMD) process has been investigated by electron microscopy imaging and analysis at different scales. In the IMD process, a pure Mg rod was used as Mg source, and nanosized SiC powders were mixed with amorphous B powders. In the case of a heat treatment at 640 °C for 1 h carried out after rolling and drawing processes, the wire has two microstructural features that degrade critical current density: uncrystallized zones composed mainly of unreacted B and SiC powders, and cracks partly filled with course Mg2Si crystals. Those cracks were formed in the uncrystallized zones as well as in crystallized MgB2 zones. It indicate that the cracks formed by the mechanical milling and drawing remain after the heat treatment.

  20. Vitamin K prophylaxis for premature infants: 1 mg versus 0.5 mg.

    Costakos, Dennis T; Greer, Frank R; Love, Laureen A; Dahlen, Lynn R; Suttie, John W


    We studied babies (22 to 32 weeks gestational age) of mothers wishing to breast-feed. Group 1 received 1 mg of vitamin K and Group 2 received 0.5 mg of vitamin K. The Day 2 plasma levels of vitamin K were 1900 to 2600 times higher on average, and the Day 10 vitamin K levels 550 to 600 times higher on average, relative to normal adult plasma values, whether an initial prophylaxis dose of 0.5 mg or 1 mg was used. We conclude that 0.5 mg as the initial dose of vitamin K intramuscularly or intravenously would likely be more than adequate to prevent hemorrhagic disease of the newborn, and that 0.3 mg/per kg may be used for babies with birth weights below 1000 g. To decrease vitamin K intakes in this population, new preparations of total parenteral nutrition multivitamins are needed.

  1. Efficient hydrogen storage with the combination of lightweight Mg/MgH2 and nanostructures.

    Cheng, Fangyi; Tao, Zhanliang; Liang, Jing; Chen, Jun


    Efficient hydrogen storage plays a key role in realizing the incoming hydrogen economy. However, it still remains a great challenge to develop hydrogen storage media with high capacity, favourable thermodynamics, fast kinetics, controllable reversibility, long cycle life, low cost and high safety. To achieve this goal, the combination of lightweight materials and nanostructures should offer great opportunities. In this article, we review recent advances in the field of chemical hydrogen storage that couples lightweight materials and nanostructures, focusing on Mg/MgH(2)-based systems. Selective theoretical and experimental studies on Mg/MgH(2) nanostructures are overviewed, with the emphasis on illustrating the influences of nanostructures on the hydrogenation/dehydrogenation mechanisms and hydrogen storage properties such as capacity, thermodynamics and kinetics. In particular, theoretical studies have shown that the thermodynamics of Mg/MgH(2) clusters below 2 nm change more prominently as particle size decreases.

  2. Mifepristone 5 mg versus 10 mg for emergency contraception: double-blind randomized clinical trial

    Carbonell JL


    Full Text Available Josep Lluis Carbonell,1 Ramon Garcia,2 Adriana Gonzalez,2 Andres Breto,2 Carlos Sanchez2 1Mediterranea Medica Clinic, Valencia, Spain; 2Eusebio Hernandez Gynecology and Obstetrics Teaching Hospital, Havana, Cuba Purpose: To estimate the efficacy and safety of 5 mg and 10 mg mifepristone for emergency contraception up to 144 hours after unprotected coitus. Methods: This double-blind randomized clinical trial was carried out at Eusebio Hernandez Hospital (Havana, Cuba. A total of 2,418 women who requested emergency contraception after unprotected coitus received either 5 mg or 10 mg mifepristone. The variables for assessing efficacy were the pregnancies that occurred and the fraction of pregnancies that were prevented. Other variables assessed were the side effects of mifepristone, vaginal bleeding, and changes in the date of the following menstruation. Results: There were 15/1,206 (1.2% and 9/1,212 (0.7% pregnancies in the 5 mg and 10 mg group, respectively (P=0.107. There were 88% and 93% prevented pregnancies in the 5 mg and 10 mg group, respectively. The side effect profiles were similar in both groups. Delayed menstruation ≥7 days was experienced by 4.9% and 11.0% of subjects in the 5 mg and 10 mg group, respectively (P=0.001. There was a significant high failure rate for women weighing >75 kg in the 5 mg group. Conclusion: It would be advisable to use the 10 mg dose of mifepristone for emergency contraception as there was a trend suggesting that the failure rate of the larger dose was lower. Keywords: mifepristone, emergency contraception

  3. The reactive Mg-liquid infiltration to obtain long superconducting MgB$_{2}$ cables

    Giunchi, G


    An alternative “in situ” process to the MgB2 wire manufacturing is represented by the Reactive Mg-Liquid Infiltration (Mg-RLI) process [1], in which the precursor wire is constituted by a metallic sheath encasing a central Mg rod, surrounded by the B powders. We demonstrated that this peculiar “internal Mg” assembly is able to produce very dense superconducting material of high critical current density, with an acceptable fill factor, up to 0.28. Furthermore the Mg-RLI allows also to easily dope the MgBB2 material either by carbon or nanoSiC powders. In order to realize long cables with this technique, two different approaches may be applied. The first one relies on the assembly of thin wires, fine enough that the liquid Mg cannot freely percolate along the wire during the reaction, and the second one relies on the assembly of thick hollow wires, reacted with a continuous supply of Mg to avoid deficiency of Mg in some part of the precursor wire. Both techniques have been demonstrated feasible and the ...

  4. The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions.

    See, Kimberly A; Chapman, Karena W; Zhu, Lingyang; Wiaderek, Kamila M; Borkiewicz, Olaf J; Barile, Christopher J; Chupas, Peter J; Gewirth, Andrew A


    Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, (27)Al and (35)Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore the active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ-Cl)3·6THF](+) complex that is observed in the solid state structure. Additionally, conditioning creates free Cl(-) in the electrolyte solution, and we suggest the free Cl(-) adsorbs at the electrode surface to enhance Mg electrodeposition.

  5. Effect of Ni on Mg based hydrogen storage alloy Mg3Nd

    TONG Yanqing; OUYANG Liuzhang; ZHU Min


    Magnesium-neodymium based alloys were prepared by induction melting in an alumina crucible under protection of pure argon atmosphere. XRD patterns show that the as-melted Mg-Nd and Mg3NdNi 0.1 diffraction peaks can be excellently indexed with D03 structure (BiF3 type, space group Fm3m ). The lattice constant of Mg3Nd phase is 0.7390 nm, which is determined by XRD analysis using Cohen's extrapolation method. The reversible hydrogen storage capacity reaches 1.95wt.% for Mg3Nd and 2.68wt.% for Mg3NdNi0.1 . The desorption of hydrogen takes place at 291 ℃ for Mg3Nd and at 250 ℃ for Mg3NdNi 0.1 . The alloys could absorb hydrogen at room temperature with rapid hydriding and dehydriding kinetics after only one cycle. The enthalpy (ΔH ) and entropy (ΔS ) of Mg3Nd-H dehydriding reaction were -68.2 kJ·mol-1 H2 and -0.121 kJ·(K·mol)-1 H2 determined by using van't Hoff plot according to the pressure-composition-isotherms (P-C-I) curve measured at different temperatures. Hydrogen absorption kinetic property of Mg3NdNi 0.1 alloy was also measured at room temperature.

  6. Comparing Doping Methodologies in Mg2Si/AgMg System

    Polymeris, G. S.; Theodorakakos, A.; Mars, K.; Godlewska, E.; Lioutas, Ch. B.; Hatzikraniotis, E.; Paraskevopoulos, K. M.


    Morphological and optical characterizations for the Mg2Si samples doped with Ag are presented. Two different doping methodologies with silver, namely in situ and ex situ doping, were studied for the case of Mg2Si of self-propagating high-temperature synthesis. Electron microscopy measurements in both scanning and transmission configurations verified the presence of AgMg precipitates embedded in the Mg2Si matrix and similar results were also yielded by FTIR spectroscopy. Finally, the dependence of silver content in both forms of dopant and inter-metallic constituent is studied upon doping technology.

  7. Confinement of Mg-MgH2 systems into carbon nanotubes changes hydrogen sorption energetics.

    Liang, Jian-jie; Kung, W-C Paul


    The density functional theory (DFT) method was used to study the effect of nanoconfinement on the energetics of Mg-MgH2 systems. Varying levels of loading of the Mg/MgH2 particles into a (10,10) carbon nanotube were examined, and the corresponding energetics were computed. A clear trend was observed that, as the level of loading increases (increasing confinement), the net energy change in the hydrogen sorption/desorption processes decreases to a significant level when the loading approaches the maximum. The confinement was found not to depend on the tube length of the confining nanotubes.

  8. Effect of Mg-Nb oxides addition on hydrogen sorption in MgH{sub 2}

    Rahman, M.W.; Castellero, A. [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy); Enzo, S. [Dipartimento di Chimica, Universita di Sassari, 07100 Sassari (Italy); Livraghi, S.; Giamello, E. [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy); Baricco, M., E-mail: [Dipartimento di Chimica IFM, NIS Centre of Excellence, Universita di Torino, Via Pietro Giuria 9, 10125 Torino (Italy)


    Highlights: > H{sub 2} sorption reactions in MgH{sub 2} with 1 mol% MgNb{sub 2}O{sub 6}, Mg{sub 4}Nb{sub 2}O{sub 9} and Mg{sub 3}Nb{sub 6}O{sub 11} have been investigated. > Ball-milled samples showed the presence of a mixture of {beta} and {gamma} allotropes of MgH{sub 2}. > The presence of Mg-Nb oxides significantly accelerates the hydrogen absorption and desorption processes. > Experimental results are discussed on the basis of thermodynamic and kinetic arguments. - Abstract: H{sub 2} absorption and desorption reactions in MgH{sub 2} promoted by ball-milling with 1 mol% MgNb{sub 2}O{sub 6}, Mg{sub 4}Nb{sub 2}O{sub 9} and Mg{sub 3}Nb{sub 6}O{sub 11} have been investigated. MgH{sub 2} was milled with the bare oxides for 12 h under a high purity Ar atmosphere. Absorption and desorption reactions in the ball-milled samples were studied by in situ X-ray diffraction (XRD) in isothermal conditions with Anton Paar XRK 900 reaction chamber. XRD patterns for absorption were recorded at 573 K under hydrogen pressure of 0.9 MPa and for desorption at 623 K in vacuum. Experimental data were analysed according to the Rietveld method. Ball-milled samples showed the presence of a mixture of {beta} and {gamma} allotropes of MgH{sub 2}, with significantly broadened diffraction peaks due to reduced crystallite size and strain, together with bare additives. The presence of Mg-Nb oxides significantly accelerates the hydrogen absorption and desorption processes. The amount of hydrogen absorbed in the presence of Mg-Nb-O phases is lower than the maximum stoichiometric capacity, because of the presence of a non-reactive MgO layer on the surface of the powders or at the grain boundaries. Experimental results are discussed on the basis of thermodynamic and kinetic arguments.

  9. Preparation of an additive-free sample with a MgH2 phase by planetary ball milling of Mg with10 wt% MgH2

    Hong, Seong-Hyeon; Song, Myoung Youp


    In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named Mg-10MgH2) was milled under hydrogen atmosphere in a planetary ball mill for different durations (2 h, 5 h, and 10 h). The hydrogen absorption and release properties of the prepared samples were investigated and compared with those of purchased pure MgH2 samples. Mg-10MgH2 milled for 5 h had the largest quantity of hydrogen released at 648 K for 100 min of 5.96 wt%. Mg-10MgH2 milled for 5 h released 0.11 wt% H for 10 min, 4.85 wt% H for 30 min, and 5.83 wt% H for 60 min at 648 K at the first cycle. Mg-10MgH2 milled for 5 h absorbed 5.39 wt% H for 5 min and 5.92 wt% H for 60 min at 648 K at the second cycle. Dehydriding curves were also obtained at the first cycle of Mg-10MgH2 samples milled for 5 h using Mg powder with or without sieving (200 mesh). The dehydriding curve at 648 K of a Mg-10MgH2 sample milled for 5 h in the planetary ball mill was compared with that of the sample milled for 24 h in a horizontal ball mill.

  10. Destabilization of Mg Hydride by Self-Organized Nanoclusters in the Immiscible Mg-Ti System

    Asano, Kohta; Westerwaal, Ruud J.; Anastasopol, Anca; Mooij, Lennard P A; Boelsma, Christiaan; Ngene, Peter; Schreuders, Herman; Eijt, Stephan W H; Dam, Bernard


    Mg is an attractive hydrogen storage material not only because of its high gravimetric and volumetric hydrogen capacities but also because of it low material costs. However, the hydride of MgH2 is too stable to release hydrogen under moderate conditions. We demonstrate that the formation of

  11. Energy Bands and Fermi Surface for beta-MgMh and beta-MgTl

    Skriver, Hans Lomholt


    The energy bands of ordered β′-MgHg and β′-MgTl have been calculated by the relativistic linear-muffintin-orbital method. We show how the gross features of the energy bands may be estimated from Wigner-Seitz rules. The densities of states are calculated and the heat capacities derived. The Fermi...

  12. Destabilization of Mg Hydride by Self-Organized Nanoclusters in the Immiscible Mg-Ti System

    Asano, Kohta; Westerwaal, Ruud J.; Anastasopol, Anca; Mooij, Lennard P A; Boelsma, Christiaan; Ngene, Peter; Schreuders, Herman; Eijt, Stephan W H; Dam, Bernard


    Mg is an attractive hydrogen storage material not only because of its high gravimetric and volumetric hydrogen capacities but also because of it low material costs. However, the hydride of MgH2 is too stable to release hydrogen under moderate conditions. We demonstrate that the formation of nanomete

  13. Demonstration of Mg2FeH6 as heat storage material at temperatures up to 550 °C

    Urbanczyk, R.; Meggouh, M.; Moury, R.; Peinecke, K.; Peil, S.; Felderhoff, M.


    The storage of heat at high temperatures, which can be used to generate electricity after sunset in concentrating solar power plants, is one of the most challenging technologies. The use of metal hydride could be one possibility to solve the problem. During the endothermic heat storage process, the metal hydride is decomposed releasing hydrogen, which then can be stored. During the exothermic reaction of the metal with the hydrogen gas, the stored heat is then released. Previous research had shown that Mg and Fe powders can be used at temperatures up to 550 °C for heat storage and shows excellent cycle stability over hundreds of cycles without any degradation. Here, we describe the results of testing of a tube storage tank that contained 211 g of Mg and Fe powders in 2:1 ratio. Twenty-three dehydrogenations (storage) and 23 hydrogenations (heat release) in the temperature range between of 395 and 515 °C and pressure range between 1.5 and 8.6 MPa were done. During the dehydrogenation, 0.41-0.42 kWhth kg-1 of heat based on material 2 Mg/Fe can be stored in the tank. After testing, mainly Mg2FeH6 was observed and small amounts of MgH2 and Fe metal can be detected in the hydride samples. This means that the heat storage capacity of the system could be further increased if only Mg2FeH6 is produced during subsequent cycles.

  14. Modification effect of lanthanum on primary phase Mg2Si in Mg-Si alloys

    WANG Liping; GUO Erjun; MA Baoxia


    The modifying effect of La addition on primary phase Mg2Si in Mg-5Si alloys was investigated. The results showed that a proper amount of La could effectively modify the primary phase Mg2Si. Based on the present experiment, the optimal modification effect was obtained with an addition of about 0.5 wt.% La. The size of the primary phase Mg2Si was considerably reduced to 25 μm or less and the morphology was modified from a coarse dendritic shape to a polyhedral shape. However, when the addition of La increased to 0.8 wt.% or higher, the primary Mg2Si grew into a coarse dendritic morphology again. Moreover, it was found that some LaSi2 compounds were formed during solidification and the amount of the compounds appeared to increase gradually with increasing La content.

  15. Microstructure and hardness of Mg-based composites reinforced with Mg2Si particles

    Mustafa Aydin; Cem Ozgür; Osman San


    Magnesium powders were mechanically alloyed with SiO2 powder particles having different particle sizes using high-energy ball milling techniques under Ar atmosphere for 1 h. The powders were consolidated with cold pressing under 560 Mpa. They were then sintered at 550℃ for 45 min under Ar atmosphere. The composites obtained on the Mg-SiO2 system were investigated using the Archimedes principle, a differential scanning calorimeter, X-ray diffraction, optic microscopy, and scanning electron microscopy. For the mechanically alloyed powders, the solid-state reaction of the synthesis of Mg2Si and MgO progressed further during sintering of the materials. The results showed that the strengthening mechanisms were dependent on dispersion hardening of fine Mg2Si and MgO particulates dispersed homogeneously in the matrix.

  16. Growth of MgO on multi-layered graphene and Mg in PVA matrix

    Marka, Sandeep K.; Mohiddon, Md. Ahamad; Prasad, Muvva D.; Srikanth, Vadali V. S. S.


    An easy and low temperature in-situ growth of MgO micro-rods on multi-layered graphene (MLG) in poly vinyl alcohol (PVA) matrix is elucidated. MLG decked with nanosized fragments of MgO and PVA are used as the starting materials to form MgO micro-rods (width = ∼1 μm and length = ∼4 μm) and MLG filled PVA composite film. Simple solution mixing, spin coating and simple drying processes are used to obtain the PVA composite. The growth mechanism of MgO micro-rods and the role of PVA in the growth of MgO micro-rods are explained on the basis of the observed morphological, structural and phase characteristics and a further controlled synthesis experiment, respectively.

  17. Mg based alloys obtained by mechanical alloying

    Ordonez, S. [Univ. de Santiago de Chile (Chile). Fac. de Ingenieria; Garcia, G.; Serafini, D.; San Martin, A.


    In the present work, we studied the production of magnesium alloys, of stoichiometry 2Mg + Ni, by mechanical alloying (MA) and the behavior of the alloys under hydrogen in a Sievert`s type apparatus. The elemental powders were milled under argon atmosphere in a Spex 8000 high energy ball mill. The milled materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Only minimum amounts of the Mg{sub 2}Ni intermetallic compound was obtained after 22 h of milling time. Most of the material was sticked to the inner surface of the container as well as to the milling balls. Powders milled only for 12 hours transforms to the intermetallic at around 433 K. Effects of the MA on the hydrogen absorption kinetics were also studied. (orig.) 10 refs.

  18. Bulk amorphous Mg-based alloys

    Pryds, Nini


    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio...... and a low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state...... are discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  19. Novel alginate based coatings on Mg alloys

    Sangeetha, K.; Roy, Abhijit [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Singh, Satish [Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261 (United States)


    Coatings on yttrium doped magnesium (Mg4Y) alloy substrates were prepared using alginate hydrogels by dip coating method to improve the surface bioactive properties of the substrate. Furthermore, composite coatings containing nano-sized calcium phosphate corresponding to hydroxyapatite (HA) phase entrapped within alginate hydrogel were also synthesized on the Mg4Y substrates. Surface characteristics of these coated substrates have been investigated using FTIR-ATR, SEM and EDS. The results show that the coatings with alginate alone are not stable in vitro; however, incorporation of NanoCaPs slightly improves the stability of these coatings. In addition, these composite coatings showed cell attachments with fibronectin incorporation. These results indicate that alginate hydrogels have the potential to be used as bioactive coating materials for different biofunctional applications.

  20. Electronic structure of MgB2

    P Modak; R S Rao; B K Godwal; S K Sikka


    Results of ab initio electronic structure calculations on the compound MgB2 using the FPLAPW method employing GGA for the exchange-correlation energy are presented. Total energy minimization enables us to estimate the equilibrium volume, / ratio and the bulk modulus, all of which are in excellent agreement with experiment. We obtain the mass enhancement parameter by using our calculated (F) and the experimental specific heat data. The c is found to be 24.7 K.

  1. Orientation relationships between icosahedral clusters in hexagonal MgZn2 and monoclinic Mg4Zn7 phases in Mg-Zn(-Y) alloys

    Rosalie, Julian M.; Somekawa, Hidetoshi; Singh, Alok; Mukai, Toshiji


    Intermetallic precipitates formed in heat-treated and aged Mg-Zn and Mg-Zn-Y alloys have been investigated via electron microscopy. Coarse spheroidal precipitates formed on deformation twin boundaries contained domains belonging to either the MgZn2 hexagonal Laves phase or the monoclinic Mg4Zn7 phase. Both phases are structurally related to the quasi-crystalline phase formed in Mg-Zn-Y alloys, containing icosahedrally coordinated zinc atoms arranged as a series of broad rhombohedral units. This rhombohedral arrangement was also visible in intragranular precipitates where local regions with the structures of hexagonal MgZn2 and Mg4Zn7 were found. The orientation adopted by the MgZn2 and Mg4Zn7 phases in twin-boundary and intragranular precipitates was such that the icosahedral clusters were aligned similarly. These results highlight the close structural similarities between the precipitates of the Mg-Zn-Y alloy system.

  2. Interstitial Fe in MgO

    Mølholt, T E; Gunnlaugsson, H P; Svane, A; Masenda, H; Naidoo, D; Bharuth-Ram, K; Fanciulli, M; Gislason, H P; Johnston, K; Langouche, G; Ólafsson, S; Sielemann, R; Weyer, G


    Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

  3. Comparison of hydrogen storage properties of pure Mg and milled pure Mg

    Myoung Youp Song; Young Jun Kwak; Seong Ho Lee; Hye Ryoung Park


    Hydrogen storage properties of pure Mg were studied at 593 K under 12 bar H2. In order to increase the hydriding and dehydriding rates, pure Mg was ground under hydrogen atmosphere (reactive mechanical grinding, RMG) and its hydrogen storage properties were subsequently investigated. Pure Mg absorbed hydrogen very slowly. At the number of cycles () of 1, pure Mg absorbed 0.05 wt% H for 5 min, 0.08 wt% H for 10 min and 0.29 wt% H for 60 min at 593 K under 12 bar H2. Activation was completed at the fifth cycle. At = 6, pure Mg absorbed 1.76 wt% H for 5 min, 2.17 wt% H for 10 min and 3.40 wt% H for 60 min. The activation of pure Mg after RMG was completed at the sixth cycle. At = 7, pure Mg after RMG absorbed 2.57 wt% H for 5 min, 3.21 wt% H for 10 min and 4.15 wt% H for 60 min.

  4. Midazolam 12 mg is moderately counteracted by 250 mg caffeine in man.

    Mattila, M J; Vainio, P; Nurminen, M L; Vanakoski, J; Seppälä, T


    Caffeine (Caf) counteracts various effects of benzodiazepines (BZDs). Since the effects of zolpidem, a short-acting atypical GABA(A)-BZD agonist, were not antagonized by Caf, we studied an interaction between Caf and midazolam (Mid) in healthy volunteers. In Study 1, 108 healthy students divided to 6 parallel groups were given Mid 12 mg (capsule) and Caf 125 and 250 mg (in decaffeinated coffee), alone and in combinations in the double-blind placebo-controlled manner. Objective and subjective tests were done before and at 45 and 90 min after intake. Ranked delta-values (changes from baseline) were analyzed by one-way contrast ANOVA and Scheffe's tests. In Study 2, six healthy subjects took Mid 15 mg (tablet) with and without Caf 300 mg. The dynamic effects were analyzed as in Study 1 and the plasma concentrations were assayed. In Study 1, learn effects after placebo (ad + 15%) were seen for letter cancellation and digit symbol substitution tests. Midazolam alone significantly (p 0.05). In conclusion, in a parallel group study, sedative effects of Mid 12 mg were only moderately antagonized by Caf 250 mg but not by Caf 125 mg. In a cross-over study, a weak interaction was found subjectively but not in objective measures.

  5. Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man.

    Mattila, M J; Nurminen, M L; Vainio, P; Vanakoski, J


    Caffeine counteracts various effects of traditional benzodiazepines (BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist, we investigated when caffeine would counteract the effects of zolpidem as well. In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg (in decaffeinated coffee) were given, alone and in combinations, to parallel groups (n = 15-17) of healthy students in double-blind and placebo-controlled manner. Objective and subjective tests were done before and 45 min and 90 min after intake. Ranked delta values (changes from baseline) were analysed by one-way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or (at -45 min) erythromycin 750 mg. Objective and subjective effects were measured and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min after zolpidem intake. In study I, practice effects after placebo (ad + 30%) were seen for letter cancellation and digit symbol substitution but not for flicker fusion tests. Zolpidem alone significantly impaired (P effects of zolpidem and either dose of caffeine matched those measured after zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem + caffeine 150 mg in impairing immediate memory and causing subjective sedation. In study II, zolpidem caused objective and subjective sedation; neither caffeine nor erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations. The sedative effects of 10 mg of zolpidem are not antagonized by 150-300 mg of caffeine in pharmacodynamic or pharmacokinetic terms.

  6. Electronic structure of ferromagnet-insulator interfaces: Fe/MgO and Co/MgO

    Mueller, M.


    In this thesis the electronic structure of Fe/MgO{sub x} and Co/MgO{sub x} ferromagnet-insulator interfaces, representing material systems which are widely used in magnetic tunnel junctions, is studied by means of spin- and angle-resolved photoemission spectroscopy. The photoemission studies focus particularly on the response of the ferromagnetic electronic system in contact with MgO of varying stoichiometries, as this reflects the mechanisms of metal-oxide bonding at real ferromagnet-insulator interfaces. The correlation between chemical bonding and electronic structure formation is analyzed by combining information from core- and valence-band photoemission spectroscopy. The spectral features are compared to band structure calculations, which are performed using the SPR-KKR method. The Fe/MgO and Co/MgO systems are prepared by molecular beam epitaxy under ultrahigh vacuum conditions on well-defined (4 x 6) GaAs(001) substrates. A structural analysis by means of low-energy electron diffraction (LEED) reveals their body-centered cubic crystalline structure, whereas the chemical characterization by Auger electron spectroscopy is used to quantify the chemical environment at the sample surfaces. The magnetic analysis, using the magneto-optical Kerr effect, reveals the uniaxial anisotropy of the ferromagnetic layers. A crucial parameter is given by the MgO degree of oxidation, which is addressed by means of core-level spectroscopy and quantified by suitable fitting procedures of the Mg 2p core level. The results of the photoemission experiments show, that the electronic structure of the Fe/MgO and Co/MgO ferromagnet/insulator interfaces and, consequently, the interfacial spin polarization are sensitively controlled by the interface chemistry. In particular, three distinct scenarios are identified: the nearly stoichiometric, the oxygen-deficient and the over-oxidized ferromagnet/MgO interface. Each case is defined by innate characteristics of the electronic structure at

  7. FeII/MgII, [Fe/Mg] Ratios and High-z Quasars

    Korista, K; Corbin, M R; Freudling, W; Korista, Kirk; Kodituwakku, Nalaka; Corbin, Michael; Freudling, Wolfram


    It has been suggested in the literature that the (Fe/alpha) abundance ratio may be used as a chronometer, due to a delay in this ratio reaching its solar value as predicted by galactic chemical evolution models. Using grids of photoionization models along a sequence of the (Fe/Mg) abundance ratio vs.\\ metallicity with time in a giant elliptical starburst scenario, we investigate the relationship between the (Fe/Mg) abundance ratio and the FeII/MgII emission line flux ratio under the assumption that these lines originate in photoionized clouds within the broad emission line regions of quasars.

  8. Lipid peroxidation in the liver of rats treated with V and/or Mg in drinking water.

    Scibior, Agnieszka; Zaporowska, Halina; Niedźwiecka, Irmina


    revealed that the changes in LPO induced by in vitro treatment of liver supernatants with exogenous Fe or V or Mg (600, 800 and 1000 microm) were a consequence of independent action of those metals and they also resulted from the interactions between Fe(exog) and V(end) and between V(end) and V(exog). In conclusion, V consumed by the rats with drinking water at a dose of 12 mg V kg(-1) body weight per 24 h for 12 weeks decreased TAS and enhanced spontaneous LPO in the hepatic tissue, which confirms its pro-oxidant potential, was also found in in vitro conditions with regard to LPO. Mg administered to rats in combination with V, at the concentration used, neither reduced nor intensified the basal LPO, compared with V-only treated animals; however, its stimulating effect on LPO was revealed in in vitro conditions, which requires further study.

  9. A first-principles study of the thermodynamic and electronic properties of Mg and MgH2 nanowires.

    Wu, Xinxing; Zhang, Ruiqi; Yang, Jinlong


    In this article, we studied the thermodynamic and electronic properties of Mg and MgH2 nanowires with different diameters, and elucidated why MgH2 nanowires are good hydrogen storage materials through first-principles calculations. Previous experiments have shown that the orientation relationship between Mg and MgH2 nanowires is the Mg[0001] direction parallel to the MgH2[110] direction. In our calculations, Mg nanowires oriented along the [0001] direction and MgH2 nanowires oriented along the [110] direction were built from bulk Mg and MgH2 crystals, respectively. We found that as the diameters of Mg and MgH2 nanowires decrease, Mg and MgH2 nanowires become more unstable, and the hydrogen desorption energies and temperatures of MgH2 nanowires decrease. That is, the thinner the MgH2 nanowires get, the more dramatically hydrogen desorption temperatures (Td) will decrease. Meanwhile, we also found that when the diameters of MgH2 nanowires are larger than 1.94 nm, the Td almost maintain the same value at about 440 K, only about 40 K lower than that of bulk MgH2 crystal; if the diameters are less than 1.94 nm, the Td reduce very quickly. In particular, compared with bulk MgH2 crystal, the Td of the thinnest MgH2 nanowire with a diameter of 0.63 nm can be reduced by 164 K. In addition, the electronic structure calculations showed that Mg nanowires are metals, while MgH2 nanowires are semiconductors. In particular, our results showed that the electronic structures of MgH2 nanowires are influenced by the surface effect and quantum size effect. That is to say, the band gaps of MgH2 nanowires are controlled by surface electronic states and the size of MgH2 nanowires.

  10. Microstructural evolution of Mg-7Al-2Sn Mg alloy during multi-directional impact forging

    M.G. Jiang


    Full Text Available Multi-directional impact forging (MDIF was applied to a Mg-7Al-2Sn (wt.% Mg alloy to investigate its effect on the microstructural evolution. MDIF process exhibited high grain refinement efficiency. After MDIF 200 passes, the grain size drastically decreased to 20 µm from the initial coarse grains of ~500 µm due to dynamic recrystallization (DRX. Meanwhile, original grain boundaries remained during MDIF and large numbers of fine spherical β-Mg17Al12 particles dynamically precipitated along the original grain boundaries with high Al concentration, acting as effective pinning obstacles for the suppression of DRXed grain growth. Besides, micro-cracks nucleated during MDIF and propagated along the interface between the remained globular or cubic Al-Mn particles and Mg matrix.

  11. Proton resonance elastic scattering of $^{30}$Mg for single particle structure of $^{31}$Mg

    The single particle structure of $^{31}$Mg, which is located in the so-called “island of inversion”, will be studied through measuring Isobaric Analog Resonances (IARs) of bound states of $^{31}$Mg. They are located in the high excitation energy of $^{31}$Al. We are going to determine the spectroscopic factors and angular momenta of the parent states by measuring the excitation function of the proton resonance elastic scattering around 0 degrees in the laboratory frame with around 3 MeV/nucleon $^{30}$Mg beam. The present study will reveal the shell evolution around $^{32}$Mg. In addition, the spectroscopic factor of the (7/2)$^{−}$ state which was not yet determined experimentally, may allow one to study the shape coexistence in this nucleus.

  12. Thermodynamic Property Study of Nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H Systems by High Pressure DSC Method

    Huaiyu Shao


    Full Text Available Mg, Ni, and Cu nanoparticles were synthesized by hydrogen plasma metal reaction method. Preparation of Mg2Ni and Mg2Cu alloys from these Mg, Ni, and Cu nanoparticles has been successfully achieved in convenient conditions. High pressure differential scanning calorimetry (DSC technique in hydrogen atmosphere was applied to study the synthesis and thermodynamic properties of the hydrogen absorption/desorption processes of nanostructured Mg-H, Mg-Ni-H, and Mg-Cu-H systems. Van’t Hoff equation of Mg-Ni-H system as well as formation enthalpy and entropy of Mg2NiH4 was obtained by high pressure DSC method. The results agree with the ones by pressure-composition isotherm (PCT methods in our previous work and the ones in literature.

  13. Magnesium homeostasis in cardiac myocytes of Mg-deficient rats.

    Michiko Tashiro

    Full Text Available To study possible modulation of Mg(2+ transport in low Mg(2+ conditions, we fed either a Mg-deficient diet or a Mg-containing diet (control to Wistar rats for 1-6 weeks. Total Mg concentrations in serum and cardiac ventricular tissues were measured by atomic absorption spectroscopy. Intracellular free Mg(2+ concentration ([Mg(2+]i of ventricular myocytes was measured with the fluorescent indicator furaptra. Mg(2+ transport rates, rates of Mg(2+ influx and Mg(2+ efflux, were estimated from the rates of change in [Mg(2+]i during Mg loading/depletion and recovery procedures. In Mg-deficient rats, the serum total Mg concentration (0.29±0.026 mM was significantly lower than in control rats (0.86±0.072 mM after 4-6 weeks of Mg deficiency. However, neither total Mg concentration in ventricular tissues nor [Mg(2+]i of ventricular myocytes was significantly different between Mg-deficient rats and control rats. The rates of Mg(2+ influx and efflux were not significantly different in both groups. In addition, quantitative RT-PCR revealed that Mg deficiency did not substantially change mRNA expression levels of known Mg(2+ channels/transporters (TRPM6, TRPM7, MagT1, SLC41A1 and ACDP2 in heart and kidney tissues. These results suggest that [Mg(2+]i as well as the total Mg content of cardiac myocytes, was well maintained even under chronic hypomagnesemia without persistent modulation in function and expression of major Mg(2+ channels/transporters in the heart.

  14. Synthesis, characterization and thermolysis studies on 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT): A key precursor in the synthesis of most powerful benchmark energetic materials (RDX/HMX) of today.

    Radhakrishnan, S; Talawar, M B; Venugopalan, S; Narasimhan, V L


    This paper reports studies undertaken on 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT). The synthesis of DPT was carried out by the nitration of hexamine based on the lines of reported method with minor modification. DPT was characterized by elemental analysis, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and (1)H nuclear magnetic resonance (NMR) techniques. Thermal stability of DPT was studied using thermogravimetry (TG) and differential scanning calorimetry (DSC). The thermal analysis studies revealed that DPT undergoes decomposition at 211 degrees C. Decomposition of DPT using TG-FTIR indicated the evolution of carbon dioxide, water and oxides of nitrogen as main gaseous products. The electrochemical behavior of DPT was studied using cyclic voltammetric (CV) studies. The experimentally determined sensitivity parameters indicated the insensitive nature of DPT towards external stimuli. The performance parameters of DPT, RDX and HMX have been computed using Linear Output Thermodynamic User Friendly Software for Energetic Systems (LOTUSES) code. The predicted properties of DPT are interesting and important from the point of process technology and/or safety. The work reported in this paper enriches the existing scanty research and development data on one of the key precursor used for synthesis of important high energy materials (HEMs).

  15. Porous Ceramic Composite ZrO2(MgO)-MgO for Osteoimplantology

    Buyakov, A. S.; Kulkov, S. N.


    Pore and crystalline structure, biocompatibility of ceramic composite ZrO2(MgO)-MgO were studied. The main mechanical characteristics were determined and it has been shown that compression strength directly depends on microstresses obtained from X-ray data. In-vitro studies of mesenchymal stromal stem cells (MMSC), cultivated on material surface are shown that cell proliferation and differentiation of MMSC goes throw osteogenic type.

  16. Flunarizine in migraine prophylaxis: efficacy and tolerability of 5 mg and 10 mg dose levels.

    Centonze, V; Magrone, D; Vino, M; Caporaletti, P; Attolini, E; Campanale, G; Albano, O


    The use of flunarizine, a drug which has proven its efficacy in migraine, is often associated with important side effects. The aim of this paper has been to check their incidence at different dose levels (5 mg vs 10 mg). Our data confirm the occurrence of important side effects (in particular weight gain); on the other hand, they emphasize the dose-dependency of the side effects.

  17. Laser cooling of MgCl and MgBr in theoretical approach

    Wan, Mingjie; Shao, Juxiang; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou, E-mail: [Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007 (China); Gao, Yufeng [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)


    Ab initio calculations for three low-lying electronic states (X{sup 2}Σ{sup +}, A{sup 2}Π, and 2{sup 2}Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas–Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f{sub 00} for A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) states for rapid laser cooling are also obtained. The proposed laser drives A{sup 2}Π{sub 3/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transition by using three wavelengths (main pump laser λ{sub 00}; two repumping lasers λ{sub 10} and λ{sub 21}). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  18. Fabrication of all-MgB Josephson junctions using MgO insulator layer

    Oba, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Goto, S. [Lightom, 95-2 Sugo, Takizawa 020-0173 (Japan); Sasaki, S.; Nakanishi, Y.; Fujino, T. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Harada, Y. [JST Satellite Iwate, Japan Science and Technology Agency, 3-35-2 Iiokashinden, Morioka, Iwate 020-0852 (Japan); Nakamura, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan); Saito, A. [Department of Electrical Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, Yamagata 992-8510 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka 020-8551 (Japan)], E-mail:


    We report on the fabrication and properties of all-MgB{sub 2} tunnel junctions with an MgO barrier. Superconductor-insulator-superconductor (SIS) junctions were fabricated on C-plane sapphire substrates. MgB{sub 2} films were grown in an ultra-high vacuum in the 10{sup -9} Torr range. The MgO insulating layer was evaporated using an electron-beam gun. SIS junctions of 30 {mu}m in diameter were fabricated by standard photolithography and Ar ion milling techniques. The critical temperature (T{sub C}) of the lower MgB{sub 2} layer after the SIS junction fabrication process was 36.7 K, which remained the same as that of the bare MgB{sub 2} film. We observed tunneling behavior in the current-voltage (I-V) characteristics of the present junctions. A superconducting gap was clearly observed at around 2.7 mV (=2{delta})

  19. Preference for rizatriptan 10-mg wafer vs. eletriptan 40-mg tablet for acute treatment of migraine.

    Láinez, M J A; Evers, S; Kinge, E; Allais, G; Allen, C; Rao, N A; Massaad, R; Lis, K


    Preference is a composite, patient-oriented endpoint incorporating efficacy, tolerability, formulation, and convenience of medications. The objective of this study was to compare patient preference for rizatriptan 10-mg wafer vs. eletriptan 40-mg tablet for acute treatment of migraine. In this multicentre, open-label, two-period, crossover study, out-patients were randomly assigned to treat the first of two moderate to severe migraines with rizatriptan or eletriptan and the second with the alternate therapy. Patients completed diary assessments at baseline and up to 24 h after taking study medication. At the last visit, patients completed a psychometrically validated preference questionnaire. A total of 372 patients (mean age 38 years, 85% female) treated two migraine attacks, and 342 patients (92%) expressed a preference for treatment. Significantly more (P rizatriptan 10-mg wafer [61.1%; 95% confidence interval (CI) 55.7, 66.3] to eletriptan 40-mg tablet (38.9%; 95% CI 33.7, 44.3). The most common reason given for preference of either treatment was speed of headache relief. At 2 h, 80% and 69% of patients reported that rizatriptan and eletriptan, respectively, was convenient or very convenient to take (mean convenience score 1.99 vs. 2.31, respectively; P rizatriptan 10-mg wafer to the eletriptan 40-mg tablet for acute treatment of migraine. The single most important reason for preference was speed of relief, consistent with results from previous preference studies.

  20. Laser cooling of MgCl and MgBr in theoretical approach.

    Wan, Mingjie; Shao, Juxiang; Gao, Yufeng; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou


    Ab initio calculations for three low-lying electronic states (X(2)Σ(+), A(2)Π, and 2(2)Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas-Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f00 for A(2)Π3/2,1/2 (υ' = 0) → X(2)Σ(+) 1/2 (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A(2)Π3/2,1/2 (υ' = 0) states for rapid laser cooling are also obtained. The proposed laser drives A(2)Π3/2 (υ' = 0) → X(2)Σ(+) 1/2 (υ″ = 0) transition by using three wavelengths (main pump laser λ00; two repumping lasers λ10 and λ21). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  1. Raman scattering study of α-MgH2 and γ-MgH2

    Kuzovnikov, M. A.; Efimchenko, V. S.; Filatov, E. V.; Maksimov, A. A.; Tartakovskii, I. I.; Ramirez-Cuesta, A. J.


    Two modifications of MgH2 have been studied by Raman spectroscopy: α-MgH2 with the P42/mnm space group and γ-MgH2 with the Pbcn space group. The latter was prepared from α-MgH2 by exposing it to a pressure of 5.6 GPa at 470 °C for 1.5 h. A comparison of the experimental spectra with ab-initio calculations allowed identification of a few phonon modes. A broad feature in the Raman spectrum of α-MgH2 in the range 1470-1790 cm-1 was identified as the B2g phonon mode. A Raman spectrum of γ-MgH2 consists of five discernible peaks at 186 cm-1, 313 cm-1, 509 cm-1, 660 cm-1, 706 cm-1 and of three broad features in the regions 890-980 cm-1, 1010-1220 cm-1 and 1240-1430 cm-1. The peaks are identified as the 1Ag (186 cm-1), 3B3g (509 cm-1), 2Ag (660 cm-1) and 3B1g (706 cm-1) phonon modes.

  2. Dehydrogenation kinetics of air-exposed MgH2/Mg2Cu and MgH2/MgCu2 studied with in situ X-ray powder diffraction

    Andreasen, A.; Sørensen, M.B.; Burkarl, R.


    The dehydrogenation kinetics of air exposed samples of MgH2/Mg2Cu and MgH2/MgCu2 have been studied with in situ time resolved X-ray powder diffraction. The X-ray setup enabled the recording of full diffraction patterns within 150 s, thereby allowing the study of structural changes combined...... sample was found to be 108 kJ/mol and 160 kJ/mol, respectively. Furthermore, substantially improved dehydrogenation kinetics of MgH2 and resistance towards oxidation of Mg due to the presence of Mg2Cu/MgCu2 are discussed in relation to previous work....

  3. Two Proton Knockout from ^32Mg

    Fallon, P.; Rodriguez-Vieitez, E.; Macchiavelli, A. O.; Clark, R. M.; Lee, I.-Y.; Wiedeking, M.; Gade, A.; Adrich, P.; Bazin, D.; Bowen, M.; Campbell, C. M.; Cook, J. M.; Dinca, D. C.; Glasmacher, T.; McDaniel, S.; Mueller, W. F.; Ratiewicz, A. F.; Siwek, K.; Terry, J. R.; Wiesshaar, D.; Yoneda, K.; Brown, B. A.; Otsuka, T.; Tostevin, J. A.; Utsuno, Y.


    We present data and calculations on the near-dripline nucleus ^30Ne. Gamma-ray decays from excited states as well as inclusive and exclusive cross-sections were measured in the ^9Be(^32Mg,^30Ne γ)X two-proton knockout reaction at incident beam energies of 99.7 and 86.7 MeV/A. The measured inclusive cross section sigma = 0.22(4)mb is suppressed compared to calculation and is indicative of a reduced overlap of initial and final state wavefunctions. We interpret this reduction as a result of large 4p4h intruder components present in ^30Ne, but not ^32Mg. Large 4p4h amplitudes are predicted to generate increased T=1 paring strengths and to help stabilize the heavier fluorine isotopes against neutron decay. A new gamma-ray transition at 1443 keV is assigned to the decay of the 4^+ state based on the spin dependent sigma for 2 proton knockout from the (d5/2)^4 configuration.

  4. Materials science of Mg-Ni-based new hydrides

    Orimo, S.; Fujii, H. [Hiroshima Univ. (Japan). Faculty of Integrated Arts and Sciences


    One of the advantageous functional properties of Mg alloys (or compounds) is to exhibit the reversible hydriding reaction. In this paper, we present our systematic studies regarding the relationship between nanometer- or atomistic-scale structures and the specific hydriding properties of the Mg-Ni binary system, such as(1) nanostructured (n)-Mg{sub 2}Ni, (2) a mixture of n-Mg{sub 2}Ni and amorphous (a)-MgNi,(3) pure a-MgNi, and(4) n-MgNi{sub 2}. Further studies on(5) an a-MgNi-based system for clarifying the effect of the short-range ordering on the structural and hydriding properties and(6) a MgNi{sub 2}-based system for synthesizing the new Laves phase structure are also presented. The materials science of Mg-Ni-based new hydrides will provide indispensable knowledge for practically developing the Mg alloys as hydrogen-storage materials. (orig.)

  5. Factors Influencing MgO Content of RE-Mg Nodularizing Alloy%REMg球化剂中MgO含量的影响因素

    杨宇鹏; 肖勇


    The effect of Mg in nodularizing alloy was introduced.When the total content of Mg was constant,the formation of MgO reduced the content of the effective Mg that would influence the nodularizing capability of the nodualrizing alloy.The source of MgO in nodularizing alloy was analyzed as follows:the MgO formed during the melting process of the nodularizing alloy and the MgO formed during the analysis sample preparing process.It was pointed out after analyzing two cases:(1) the MgO content of nodularizing alloy is the main factor influencing its nodularzing capability,therefore the MgO content should be reduced by improving its melting process; (2)In order to ensure the veracity of MgO content test it's necessary to use correct sample preparing method.%介绍了Mg在球化剂中的作用.当w(Mg总)一定时,MgO的生成降低了w(Mg有效)的含量,影响到球化剂的球化能力.分析了球化剂中MgO的来源:球化剂熔炼过程中产生MgO、在制取分析样品过程中产生MgO.通过2个案例的分析,指出:(1)球化剂中MgO含量的高低是影响其球化能力的主要因素,应通过改进熔炼工艺来降低w(MgO)量;(2)为确保球化剂中w(MgO)量检测的准确性,应采用正确的样品制备方法.

  6. Effect of Mg and C contents in MgCNi3, and structure and superconductivity of MgCNi3-xCox


    The effect of Mg and C contents on TC in MgCNi3, and structure and superconductivity of MgCNi3-xCox were studied. It is found that the excess of Mg and C in initial material mixture is favorable to improvement in TC and helps to obtain single_phase samples. For preparing MgCNi3 superconductor, the optimum composition of starting materials is MgC1.45Ni3 with excess of Mg (20 wt.%) of the stoichiometric composition. In MgCNi3-xCox system, a continuous solid solution is formed, lattice parameter decreases slightly and TC decreases obviously with increasing x. A suppression of superconductivity is observed due to the substitution of Co (Mn) for Ni. The suppression effect is smaller for the substitution of Co than that of Mn.

  7. Electrochemical formation of Mg-Li-Ca alloys by codeposition of Mg, Li and Ca from LiCl-KCl-MgCl2-CaCl2 melts.

    Yan, Yong De; Zhang, Mi Lin; Xue, Yun; Han, Wei; Cao, Dian Xue; Jing, Xiao Yan; He, Li Yi; Yuan, Yi


    This work presents electrochemical formation of Mg-Li-Ca alloys via codeposition of Mg, Li and Ca on a molybdenum electrode in KCl-LiCl-MgCl(2)-CaCl(2) melts at 943 K. Cyclic voltammograms (CVs) showed that the underpotential deposition (UPD) of calcium on pre-deposited magnesium leads to the formation of a liquid Mg-Ca alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Ca alloy leads to the formation of a liquid Mg-Li-Ca solution. Chronopotentiometric measurements indicated that the codepositon of Mg, Li and Ca occurs at current densities more negative than -0.31 A cm(-2) in LiCl-KCl-MgCl(2) (5 wt%) melts containing 1 wt% CaCl(2). Chronoamperograms demonstrated that the onset potential for the codeposition of Mg, Li and Ca is -2.200 V, and the codeposition of Mg, Li and Ca is formed when the applied potentials are more negative than -2.200 V. X-Ray diffraction (XRD) indicated that Mg-Li-Ca alloys with different phases were formed via galvanostatic electrolysis. The microstructures of typical alpha and beta phases of Mg-Li-Ca alloys were characterized by optical microscope (OM) and scanning electron microscopy (SEM). The analysis of energy dispersive spectrometry (EDS) showed that the element Ca mainly distributes along grain boundary in Mg-Li-Ca alloys. The results of inductively coupled plasma analysis determined that the chemical compositions of Mg-Li-Ca alloys correspond with the phase structures of XRD patterns, and the lithium and calcium contents of Mg-Li-Ca alloys depend on the concentrations of MgCl(2) and CaCl(2).

  8. Decay of a narrow and high spin {sup 24}Mg + {sup 24}Mg resonance

    Salsac, M.-D. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France)], E-mail:; Haas, F.; Courtin, S. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Algora, A. [INR, Debrecen (Hungary); Beck, C. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Beghini, S. [Universita di Padova and INFN, Padova (Italy); Behera, B.R. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Chapman, R. [University of the West of Scotland, Paisley (United Kingdom); Corradi, L. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Dombradi, Z. [INR, Debrecen (Hungary); Farnea, E. [Universita di Padova and INFN, Padova (Italy); Fioretto, E.; Gadea, A. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Jenkins, D.G. [University of York, York (United Kingdom); Latina, A. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Lebhertz, D. [IPHC, Universite Louis Pasteur, CNRS-IN2P3, Strasbourg (France); Lenzi, S. [Universita di Padova and INFN, Padova (Italy); Liang, X. [University of the West of Scotland, Paisley (United Kingdom); Marginean, N. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Montagnoli, G. [Universita di Padova and INFN, Padova (Italy)] (and others)


    The {sup 24}Mg + {sup 24}Mg reaction has been studied at the Legnaro Tandem at a CM bombarding energy of 45.7 MeV where a narrow and high spin resonance has been reported previously. The decay of the resonance into the inelastic and fusion-evaporation channels has been investigated. The ON and OFF resonance decay yields have been measured using, for the inelastic channels, the fragment spectrometer PRISMA and the {gamma} array CLARA, and, for the fusion-evaporation channels, the Si array EUCLIDES and the {gamma} array GASP. Strong resonant effects have been observed in the inelastic channels involving the 2{sub 1}{sup +} and 4{sub 1}{sup +} states of the {sup 24}Mg ground state band. Weaker effects are also seen in certain fusion-evaporation channels. The properties of the studied resonance are in agreement with molecular model predictions. It is also proposed that the narrow and high spin {sup 24}Mg + {sup 24}Mg resonance corresponds to the formation of a fast rotating and highly prolate deformed {sup 48}Cr after a Jacobi shape transition and just before fission.

  9. Mechanical Properties of Mg-Gd and Mg-Y Solid Solutions

    Kula, Anna; Jia, Xiaohui; Mishra, Raj K.; Niewczas, Marek


    The mechanical properties of Mg-Gd and Mg-Y solid solutions have been studied under uniaxial tension and compression between 4 K and 298 K (-269 °C and 25 °C). The results reveal that Mg-Gd alloys exhibit higher strength and ductility under tension and compression attributed to the more effective solid solution strengthening and grain-boundary strengthening effects. Profuse twinning has been observed under compression, resulting in a material texture with strong dominance of basal component parallel to compression axis. Under tension, twining is less active and the texture evolution is controlled mostly by slip. The alloys exhibit pronounced yield stress asymmetry and significantly different work-hardening behavior under tension and compression. Increasing of Gd and/or Y concentration leads to the reduction of the tension-compression asymmetry due to the weakening of the recrystallization texture and more balanced twinning and slip activity during plastic deformation. The results suggest that under compression of Mg-Y alloys slip is more active than twinning in comparison to Mg-Gd alloys.

  10. Refinements in an Mg/MgH2/H2O-Based Hydrogen Generator

    Kindler, Andrew; Huang, Yuhong


    Some refinements have been conceived for a proposed apparatus that would generate hydrogen (for use in a fuel cell) by means of chemical reactions among magnesium, magnesium hydride, and steam. The refinements lie in tailoring spatial and temporal distributions of steam and liquid water so as to obtain greater overall energy-storage or energy-generation efficiency than would otherwise be possible. A description of the prior art is prerequisite to a meaningful description of the present refinements. The hydrogen-generating apparatus in question is one of two versions of what was called the "advanced hydrogen generator" in "Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators" (NPO-43554), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 52. To recapitulate: The apparatus would include a reactor vessel that would be initially charged with magnesium hydride. The apparatus would exploit two reactions: The endothermic decomposition reaction MgH2-->Mg + H2, which occurs at a temperature greater than or equal to 300 C, and The exothermic oxidation reaction MgH2 + H2O MgO + 2H2, which occurs at a temperature greater than or equal to 330 C.

  11. Formation and Stability of Hollow MgO Nanoshells

    Krishnan, G.; Palasantzas, G.; Kooi, B.J.


    High temperature annealing of gas phase synthesized Mg nanoparticles surrounded by an MgO shell leads to formation of hollow MgO nanoshells due to the evaporation assisted Kirkendall effect. Under electron beam exposure in TEM, the (220) MgO facets reduce their high surface energy by forming cube fa

  12. cDNA library Table: mg [KAIKOcDNA[Archive

    Full Text Available mg NA mg-- p50 midgut fifth instar larval stage D3 mixed pBluescript SK- EcoR1 for ...5' Xho1for 3' sequenced from T3 primer (5' -> 3') AU001868-AU002476,BY916287-BY916543 mg[number],mg[number]_1 ...

  13. The three shapes of 32Mg

    Poves A.


    Full Text Available The N=20 and N=28 “islands of inversion” are described by large scale shell model calculations which mix configurations with different Nħω or equivalently with different number of particles promoted from the sd-shell to the pf -shell. We pay particular attention to the properties of the states at fix Nħω which turn out to be the real protagonists of the physics at N=20. In particular we study the appearance of spherical, deformed and superdeformed structures in 32Mg at fixed 0p-0h, 2p-2h and 4p-4h configurations. Finally we submit that the islands of deformation at N=20 and N=28 merge in the Magnesium isotopes

  14. Simultaneous polymerization of Mg and Zr alkoxides

    Mendez-Vivar, J.; Lara, V.H. [Univ. Autonoma Metropolitana-Iztapalapa, Depto. de Quimica, Mexico, D. F. (Mexico); Mendoza-Serna, R.; Ayala-Morales, A. [Facultad de Estudios Superiores Zaragoza, UNAM, Carrera de Ingenieria Quimica, Mexico, D. F. (Mexico); Bosch, P. [Inst. de Investigaciones en Materiales, UNAM Circuito Exterior, Mexico, D. F. (Mexico)


    The preparation of homogeneous MgO-ZrO{sub 2} ceramics by the sol-gel process is of interest because of its potential technological applications as dielectric materials in thin films and membranes. In this work we used magnesium methoxide and zirconium n-propoxide as precursors. The simultaneous polymerization of the alkoxides was performed via the sol-gel process, using acetylacetone (acacH) and isoeugenol (isoH) separately as the chelating agents, in order to control the hydrolysis and condensation steps. Spectroscopic studies have been performed on the sols, gels, xerogels and oxides, including Fourier transform infrared (FTIR) spectroscopy and small Angle X-ray Scattering (SAXS). (orig.)

  15. Mg II Absorbing Galaxies: Morphologies and Kinematics

    Churchill, C; Kacprzak, G G; Churchill, Chris; Steidel, Chuck; Kacprzak, Glenn


    In this contribution, we review our current knowledge of the properties of galaxies, and their extended halos, selected by MgII absorption in the spectra of background quasars. We then describe recent efforts to quantify the morphologies and orientations of galaxies and explore how these relate to the gas kinematics. In a sample of 26 galaxies, we find no clear connection between the orientation of the quasar line of sight through the galaxy and the velocity spread of the gas. However, it appears that the quantity of gas "stirred up" in the halo may be correlated to asymmetry in the galaxy morphology. Since the galaxies have fairly normal morphologies, this connection may suggest that galaxies with extended halos experienced an interaction or merging event a few dynamical times prior to the epoch of observation.

  16. Multiaxial magnetic ordering in NdMg

    Deldem, M; Galera, R M; Morin, P; Schmitt, D; Ouladdiaf, B


    NdMg is a cubic compound (CsCl-type) which orders antiferromagnetically at T sub N =61 K. The magnetization measurements show a second transition at T sub R =35 K. Over the whole order range, the powder neutron diffraction pattern can be indexed on the hypothesis of a collinear structure, the magnetic moments being parallel to the wave vector. The neutron diffraction experiments on a single crystal, under an applied magnetic field, establish that the transition at T sub R corresponds to a change from a collinear structure to a multiaxial one. The magnetic moments successively point along a fourfold axis, in the collinear structure, and along twofold axes in the multiaxial one. This sequence of magnetic structures is consistent with the coexistence of ferroquadrupolar gamma-couplings and antiferroquadrupolar epsilon-couplings. (author)

  17. Preparation of Mg-MgH2 flakes by planetary ball milling with stearic acid and their hydrogen storage properties

    Hong, Seong-Hyeon; Song, Myoung Youp


    Many studies preparing magnesium hydride using catalyst addition were performed, resulting in the preparation of additive-containing magnesium hydride. Preparation of a sample with a MgH2 phase without additives requires high pressure and high temperature and is time-demanding. In order to prepare an additive-free sample with a MgH2 phase, 90 wt% Mg+10 wt% MgH2 (named 90Mg+10MgH2) was milled under a hydrogen atmosphere with 6 wt% stearic acid as a process-controlling agent, which led to a formation of Mg-MgH2 flakes. The hydrogen storing and releasing properties of the prepared flakes were investigated and compared with those of purchased MgH2. A sample with a majority fraction of MgH2 phase was prepared by planetary ball milling of 90 Mg+10 MgH2 with 6 wt% stearic acid. The resultant particles of 90 Mg+10 MgH2 obtained after hydridingdehydriding cycling were much smaller and had significantly more cracks and defects than those of MgH2 after hydriding-dehydriding cycling. 90 Mg+10 MgH2 released 0.12 wt% hydrogen for 4 min, 3.70 wt% for 20 min, and 5.30 wt% for 60 min at 648 K at the first cycle.

  18. Estabilidad de tabletas de Rifampicina 300 mg

    Lisette Martínez Miranda


    Full Text Available Se realizó el estudio de estabilidad de las tabletas de rifampicina 300 mg. Se utilizó para la cuantificación del principio activo un método analítico desarrollado y validado por cromatografía líquida de alta resolución en fase reversa y detección ultravioleta. El estudio de estabilidad de las tabletas se efectuó mediante los métodos de vida útil y acelerado en condiciones isotérmicas; no se obtuvo una variación notable de la concentración en el tiempo de estudio y se demostró así la estabilidad química y térmica del principio activo, por lo que se proponen 2 años como fecha de vencimiento. La humedad relativa de 75, 84 y 92 % tuvo influencia en la estabilidad de la formulación en el período analizado.The stability study of rifampicin 300 mg was conducted. An analytical method developed and validated by high pressure liquid chromatography in reverse phase and ultraviolet detection was used for the quantification of the actives principle. The stability study of the tablets was conducted by the method of useful life and the accelerated method under isothermic conditions. There was no significant variation of the concentration during the time of study and, thus, the chemical and thermal stability of the active principle was proved. A period of 2 years was proposed as expiration date. A relative humidity of 75, 84 and 92% influenced on the stability of the formulation in the analyzed period.

  19. Evidence for beta -delayed neutron emission from /sup 31/Mg and /sup 32/Mg

    Zaidins, C S; De Saint-Simon, M; Détraz, C; Epherre-Rey-Campagnolle, Marcelle; Guillemaud, D; Klapisch, Robert; Langevin, M; Naulin, F; Thibault, C; Touchard, F


    Investigates the time spectrum of beta -delayed neutron emission from /sup 30-34/Na and their descendants using beta -neutron coincidence detection. The authors have been able to assign an upper limit of 0,4% to the probability of beta -delayed neutron emission, p/sub n/, from the /sup 30/Na daugher isotope /sup 30/Mg. In fitting the time spectra of beta -delayed neutrons from /sup 31/Na and /sup 32/Na, we find a definitive component from subsequent daughter decay as well. This provides evidence for beta -delayed neutron emission from /sup 31/Mg and /sup 32/Mg with P/sub n/ values of the order of 2% for each. (7 refs).

  20. Ageing processes in Al-Cu-Mg alloys with different Cu/Mg ratios

    Macchi, C. [IFIMAT, UNCentro and CONICET, Pinto, Tandil (Argentina); Somoza, A. [IFIMAT, UNCentro and CICPBA, Pinto, Tandil (Argentina); Ferragut, R.; Dupasquier, A. [LNESS and CNISM, Politecnico di Milano, Como (Italy); Polmear, I.J. [Emeritus Professor, Department of Materials Engineering, Monash University, Melbourne, Vic. (Australia)


    Three age-hardenable Al-Cu-Mg alloys with different Cu/Mg ratios were studied by means of positron annihilation lifetime spectroscopy and Vickers hardness as a function of the artificial ageing time at 175 C. Complementary information on the decomposition sequence was obtained by means of differential scanning calorimetry. The results are discussed in terms of the different structures that are formed during the precipitation sequence of the supersaturated solid solution. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)



    The objective of the present work is to study the casting characteristics of various Al-Li alloys, which include fluidity and strengths of the alloys and their interaction with cast molds. Materials investigated are Al-Li-Mg and Al-Li-Cu-Mg alloys with Li content of 2.5 wt%. The results show that sand molds with resin binders are good for Al-Li casting. Ceramic coatings can further reduce the metal-mold interactions. However, the permeability is also reduced by coating. The fluidity of Li-bea...

  2. Porous composite materials ZrO{sub 2}(MgO)-MgO for osteoimplantology

    Buyakov, Ales, E-mail: [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Litvinova, Larisa, E-mail:; Shupletsova, Valeria, E-mail: [Immanuel Kant Baltic Federal University, Kaliningrad (Russian Federation); Kulbakin, Denis, E-mail: [Tomsk Cancer Research Institute, Tomsk, 634050 (Russian Federation); Kulkov, Sergey, E-mail: [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)


    The pore structure and phase composition of ceramic composite material ZrO{sub 2}(Mg)-MgO at different sintering temperatures were studied. The main mechanical characteristics of the material were determined and it was shown that they are close to the characteristics of natural bone tissues. It was shown that material structure has a positive effect on the pre-osteoblast cells proliferation. In-vitro studies of pre-osteoblast cells, cultivation on material surface showed a good cell adhesion, proliferation and differentiation of MMSC by osteogenic type.

  3. Phase transition and optoelectronic properties of MgH2

    Nayak, Vikas; Verma, U. P.


    In this article, structural and electronic properties of MgH2 have been studied. The aim behind this study was to find out the ground state crystal structure of MgH2. For the purpose, density functional theory (DFT)-based full-potential linearized augmented plane wave (FP-LAPW) calculations have been performed in three different space groups: P42/mnm (α-MgH2), Pa3 (β-MgH2) and Pbcn (γ-MgH2). It has been found that the ground state structure of MgH2 is α-MgH2. The present study shows that α-MgH2 transforms into γ-MgH2 at a pressure of 0.41 GPa. After further increase in pressure, γ-MgH2 transforms into β-MgH2 at a pressure of 3.67 GPa. The obtained results are in good agreement with previously reported experimental data. In all the studied phases, the behavior of MgH2 is insulating and its optical conductivity is around 6.0 eV. The α-MgH2 and γ-MgH2 are anisotropic materials while β-MgH2 is isotropic in nature.

  4. The Influence of MgH2 on the Assessment of Electrochemical Data to Predict the Degradation Rate of Mg and Mg Alloys

    Wolf-Dieter Mueller


    Full Text Available Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys.

  5. The influence of MgH2 on the assessment of electrochemical data to predict the degradation rate of Mg and Mg alloys.

    Mueller, Wolf-Dieter; Hornberger, Helga


    Mg and Mg alloys are becoming more and more of interest for several applications. In the case of biomaterial applications, a special interest exists due to the fact that a predictable degradation should be given. Various investigations were made to characterize and predict the corrosion behavior in vitro and in vivo. Mostly, the simple oxidation of Mg to Mg2+ ions connected with adequate hydrogen development is assumed, and the negative difference effect (NDE) is attributed to various mechanisms and electrochemical results. The aim of this paper is to compare the different views on the corrosion pathway of Mg or Mg alloys and to present a neglected pathway based on thermodynamic data as a guideline for possible reactions combined with experimental observations of a delay of visible hydrogen evolution during cyclic voltammetry. Various reaction pathways are considered and discussed to explain these results, like the stability of the Mg+ intermediate state, the stability of MgH2 and the role of hydrogen overpotential. Finally, the impact of MgH2 formation is shown as an appropriate base for the prediction of the degradation behavior and calculation of the corrosion rate of Mg and Mg alloys.

  6. Heavy Metals (Mg, Mn, Ni and Sn contamination in Soil Samples of Ahvaz II Industrial Estate of Iran in 2013

    Soheil l Sobhanardakani


    Full Text Available Background & Aims of the Study: Due to the rapid industrial development in Khuzestan province of Iran during recent years, this study was performed to analyze the variation of metals concentrations (Mg, Mn, Ni, and Sn in soil samples of Ahvaz II Industrial estate during the spring season of 2013. Materials & Methods: In this experimental study, 27 topsoil samples were collected from nine stations. The intensity of the soil contamination was evaluated, using a contamination factor (Cf and geo-accumulation index (I-geo. Results:  The mean soil concentrations (in mg kg-1 (dry weight were in ranged within 870-1144 (Mg, 188-300 (Mn, 93-199 (Ni and 9-15 (Sn. The data indicated that the I-geo value for all metals falls in class ‘1’. Also the Cf value for Mg and Mn falls in class ‘0’, the Cf value for Sn falls in class ‘1’ and the Cf value for Ni falls in the classes of ‘1’ and ‘2’. The result of the Pearson correlation showed that there were significant positive associations between all metals. Conclusions: According to the results which were achieved by a cluster analysis, there were significant positive associations among all metals based on Pearson correlation coefficient, especially between Ni and Sn; also both of them with Mn. Because the Ni originates from oil sources it can be resulted that Mn and Sn originate from oil sources, too. Therefore, industrial activities and exploitation of oil reservoirs are the main cause of pollution in that area. Also, it can be concluded that, with increasing the distance from the source of pollution, the accumulation of contaminants in the soil samples decreased.

  7. Calibration of the DH6500-MG02 and DH6500-MG03 antennas

    Nielsen, Jeppe Majlund; Pivnenko, Sergey

    frequencies. For the DH6500-MG03 horn the measurement comprises on-axis gain, and on-axis polarization at 601 frequencies. For both horns, the input reection coecient was measured at 601 frequencies. The measurement was carried out at the DTU-ESA Spherical Near-Field Antenna Test Facility in April 2013...

  8. Mechanical and Corrosive Properties of Two Magnesium Wires: Mg4Gd and Mg6Ag

    Maier, Petra; Szakács, Gabor; Wala, Marcin; Hort, Norbert

    The mechanical and corrosive properties of two Magnesium wires are studied in the field of microhardness, tension-, compression-and 3-point-bending tests, corrosion and its influence on the mechanical properties. Due to recrystallization during their complex forming processes (casting, extrusion, wire drawing), both wires show a fine grained microstructure resulting in high strength and ductility. However, the ductility is mostly evaluated by 3-point bending and compression; due to the notch effect in the clamp area, the maximum tensile strength and elongation under tension cannot be measured. Both alloys show a tensile-compressive yield asymmetry. Even RE-elements are known to reduce this asymmetry, the Mg-Gd alloy shows 100 MPa higher strength in tension than compression. The asymmetry of the Mg-Ag wire is similar. Overall the wires show very high strength and hardness, Mg6Ag slightly higher compared to Mg4Gd. Strong pitting corrosion is found and reduces strongly the tensile and bending strength.

  9. Nanometric MgFe2O4: Synthesis, characterization and its application towards supercapacitor and electrochemical uric acid sensor

    Majumder, S.; Kumar, S.; Banerjee, S.


    In this paper, we have synthesized nanocrystalline MgFe2O4 (S1) by auto-combustion assisted sol-gel method. The structure and morphology and elemental study of S1 are examined by powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FESEM) and energy dispersive X-ray spectroscopic (EDS) techniques. The FESEM images reveal that the morphology of the sample is rough and average particle size is 50 nm. The PXRD study indicates that the samples are well crystalline and single phase in nature. Moreover, we have performed supercapacitor study by electrochemical galvanostatic charge-discharge (GCD) measurement, which shows pseudo capacitive behavior. S1 contains a high specific capacitance of 428.9 Fg-1 at the current density 0.0625 Ag-1 and can deliver high energy and power density of 18.01 Wh kg-1 and 21468 Wkg-1 respectively. Moreover, uric acid (UA) sensing study has also been performed by cyclic voltmetry (CV) and electrochemical impedance spectroscopy measurement (EIS) of S1. We can use nanocrystalline MgFe2O4 as supercapacitor and UA sensor applications purpose.


    Sikander A . K


    Full Text Available Macular edema is a frequent manifestation of diabetic retinopathy and animportant cause of visual disturbance in diabetic patients. AIM: To compare the efficacy and safety of 1mg and 4mg intravitreal triamcinolone acetonide (IVTA in the management of diabetic macular edema. SETTING: Sarojini Devi Eye Hospital, Hyderabad. MATERIAL AND METHODS: 42 eyes of 42 patients with diabetic macular edema were randomly assigned torecei ve either 1 - mg or 4 - mg dose of Intravitreal triamcinolone acetonide (IVTA. Each patient underwent a complete comprehensive eye examination at baseline andat each visit.Fundus fluorescein angiography and optical coherence angiographywas done at baseline an d at 1, 3 and 6 months.BCVA, lens status, IOP wererecorded at each follow up visit. Each patient’s BCVA was measured in snellen’s lines and converted into logarithm of minimum angle of resolution (log MAR scale for analysis. STATISTICAL ANALYSIS USED : The data were statistically evaluated using the Wilcoxon signedrank test, Mann - Whitney test and t tests wherever applicable. A p value of lessthan . 05 was considered significant. RESULTS: There was no statistically significant difference in the mean foveal thickness measurement at baseline (p=.723 or at 3 rd month (p=.878 between the sub - groups. BCVA significantly improved from baseline to subsequent visits in both the groups, but there was no statistically significant difference observed in the mean baseli ne BCVA between the two sub - groups (p=.754. There was no statistically significant difference observed in IOP between the two sub - groups at any follow up visit. CONCLUSIONS: The results of our study suggest that 1 - mg dose of IVTA is as effective as 4 - mgdo se of IVTA in improving the functional and anatomical outcome in macularedema associated with diabetic retinopathy.

  11. Comparison of initial loading doses of 5 mg and 10 mg for warfarin therapy

    Sidnei Lastória


    Full Text Available CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil. OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment. METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3. This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range. RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days, were on lower doses at discharge and had better therapeutic indicators at the first return appointment. CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.

  12. Pressure-induced structural transitions in MgH2.

    Vajeeston, P; Ravindran, P; Kjekshus, A; Fjellvåg, H


    The stability of MgH2 has been studied up to 20 GPa using density-functional total-energy calculations. At ambient pressure alpha-MgH2 takes a TiO2-rutile-type structure. alpha-MgH2 is predicted to transform into gamma-MgH2 at 0.39 GPa. The calculated structural data for alpha- and gamma-MgH2 are in very good agreement with experimental values. At equilibrium the energy difference between these modifications is very small, and as a result both phases coexist in a certain volume and pressure field. Above 3.84 GPa gamma-MgH2 transforms into beta-MgH2, consistent with experimental findings. Two further transformations have been identified at still higher pressure: (i) beta- to delta-MgH2 at 6.73 GPa and (ii) delta- to epsilon-MgH2 at 10.26 GPa.

  13. Magnetocaloric phenomena in Mg-ferrite nanoparticles

    Burianova, S; Holec, P; Plocek, J [Charles University, Faculty of Science, Department of Inorganic chemistry, Prague (Czech Republic); Poltierova-Vejpravova, J, E-mail: burianovasimona@email.c, E-mail: jana@mag.mff.cuni.c


    A comparative study of magnetocaloric effect (MCE) in superparamagnetic (SPM) regime is reported in two different types of magnesium ferrite nanostructures. The samples were prepared either by microemulsion method as MgFe{sub 2}O{sub 4} nanoparticles encapsulated in amorphous SiO{sub 2}, or as matrix-less nanoparticles using hydrothermal synthesis in supercritical water conditions. The particle diameter in all prepared samples was obtained from XRD measurements and TEM analysis. All samples show a SPM behavior above the blocking temperature, T{sub B}. The entropy change, {Delta}S was finally derived from the measurements of magnetization, M(H,T) curves at defined temperature intervals. We observed, that all samples show a broad peak of {Delta}S in the temperature range that is fairly above the T{sub B}. The values of the {Delta}S also depend on the particle size, and they are of about two orders lower than those reported in the famous giant magnetocaloric materials.

  14. Three new energetic complexes with N,N-bis(1H-tetrazole-5-yl)-amine as high energy density materials: syntheses, structures, characterization and effects on the thermal decomposition of RDX.

    Yang, Qi; Song, Xiaxia; Zhang, Wendou; Hou, Lei; Gong, Qibing; Xie, Gang; Wei, Qing; Chen, Sanping; Gao, Shengli


    Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods. Based on the constant-volume combustion energies measured by a precise rotating-bomb calorimeter, the standard molar enthalpies of formation of 1 and 2 were determined. The calculation of the detonation properties of 1 and 2 and the impact sensitivity tests of 1, 2 and 3 were carried out. In addition, 1, 2 and 3 were explored as combustion promoters to accelerate the thermal decompositions of RDX (1,3,5-trinitro-1,3,5-triazine) by differential scanning calorimetry. Experimental results showed that 1, 2 and 3 can be used as HEDMs in the field of combustion promoters and insensitive 2 can be regarded as a safer form for mass storage and transportation than sensitive 3.

  15. Study on kinetics of drawing Al from high explosive of TNT/RDX/Al%梯黑铝混合装药提取铝的反应动力学研究

    姬文苏; 丁玉奎; 李金明; 龚华雄


    The reaction kinetic of drawing Al from high explosive of TNT/RDX/Al was approached using shrinking unreacted core model. The effect of temperature,concentration and size of explosive on reaction speed was investigated. The results show that the leaching process of drawing Al meets kinetic equation g(x) = 1 - (1-x )1/3 =kt. The leaching kinetic is controlled by chemical reaction,and activation energy is 42. 392 kJ/mol. Regression analysis was applied based on theory model, finding that apparent reaction speed i8 linear with regards to the concentration of H2SO4 ( Co) and the size of explosive( 1/r02).%采用"颗粒不变收缩芯模型"研究了梯黑铝装药中Al的酸解反应动力学行为,考察了反应温度、硫酸浓度及炸药粒度对反应速率的影响.结果表明,Al的酸浸过程符合动力学方程g(x)=1-(1-x)1/3=kt,为化学反应控制类型,表观活化能为42.392KJ/mol.在此基础上,经线性回归分析,发现表观反应速率常数k与硫酸初始浓度C0及炸药粒径1/r02成正比例关系.

  16. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    Najafi, Sarvenaz; Jalali, Mohsen


    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints.

  17. Structural relationships among MgZn2 and Mg4Zn7 phases and transition structures in Mg-Zn-Y alloys

    Rosalie, Julian M.; Somekawa, Hidetoshi; Singh, Alok; Mukai, Toshiji


    Isothermal ageing of plastically deformed Mg-Zn-Y alloys resulted in precipitation along ? twin boundaries. The bulky precipitates so formed had structures similar to those recently reported for the rod-like ? precipitates, but afforded a more detailed study by high-resolution TEM due to their larger size. The core of the precipitates often had the structure of the monoclinic Mg4Zn7 phase, and had the orientation ? ; ? with either the matrix or the twin. On this Mg4Zn7 phase, the hexagonal MgZn2 phase grew in two orientations, both with ? . One of these orientations formed a known orientation relationship ? ; ? with the matrix. The part of the precipitate with the MgZn2 structure was usually in direct contact with the twin boundary. Both the Mg4Zn7 and MgZn2 phases have layered structures that can be described with similar building blocks of icosahedrally coordinated atoms. The atomic positions of zinc atoms comprise the vertices of these icosahedra and form 'thick' rhombic tiles. The orientations of these rhombuses remain unchanged across the interfaces between the two phases. Near the interface with MgZn2, transition structures formed in the Mg4Zn7 phase, with the Zn:Mg atom ratio between those of the Mg4Zn7 and MgZn2 phases. In these transition structures, the unit cell of the Mg4Zn7 phase is extended along [100] or [001] by half a unit cell length by continuation of the rhombic tiling. Structures of these extended unit cells are proposed.

  18. Effects of Ca additions on some Mg-alloy hydrides

    Lupu, D.; Biris, A.; Indrea, E.; Bucur, R.V.


    The hydrogenation of the alloy of composition CaMg/sub 1/ /sub 8/Ni/sub 0/ /sub 5/ containing CaMg/sub 2/ and MgNi/sub 2/ shows fast activation kinetics. The Mg/sub 2/Ni phase is observed in the dehydrided samples. The three plateaus on the hydrogen desorption isotherms correspond to the most stable magnesium hydrides observed up to now in Mg-alloy ( H = 20 to 24 kcal/mol H/sub 2/). The effects of Ca additions on the hydrogen storage capacity and desorption rates of some Mg-rich alloys have been studied. 16 references, 3 figures, 1 table.

  19. Pressureless sintering of translucent MgO ceramics

    Chen Dianying [Department of Chemical, Materials and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Jordan, Eric H. [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States)], E-mail:; Gell, Maurice [Department of Chemical, Materials and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States)


    MgO nanocrystalline powders were synthesized via a wet precipitation process. X-ray diffraction analysis of the heat-treated precursor powders shows that a crystalline MgO phase forms at {approx}500 deg. C. Translucent MgO ceramics were prepared by pressureless sintering the nanocrystalline MgO powders at 1400 deg. C for 2 h under ambient atmosphere. The as-sintered MgO ceramics have a relative density of 98.1% with an average hardness of 6.8 GPa. Scanning electron microscope characterization revealed that the translucent MgO ceramics have an average grain size of {approx}6 {mu}m.

  20. Phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350℃

    LI Hongxiao; REN Yuping; HUANG Mingli; CHEN Qin; HAO Shiming


    The phase equilibria in the Mg-rich corner of the Mg-Zn-La system at 350℃ have been investigated by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. It has been shown that the linear compound (Mg,Zn)17La2 existed in the Mg-Zn-La system at 350℃. The linear compound (so-called T phase) was with the C-centred orthorhombic crystal structure induced by the solution of significant quantities of the third element. The three-phase region α(Mg) + MgZn(La) + T and the two-phase region composed of the α(Mg) and the linear-compound T phase existed in the Mg-rich corner of the Mg-Zn-La system at 350℃.

  1. Structural and electronic properties of Mg and Mg-Nb co-doped TiO2 (101) anatase surface

    Sasani, Alireza; Baktash, Ardeshir; Mirabbaszadeh, Kavoos; Khoshnevisan, Bahram


    In this paper, by using density functional theory, Mg and Nb-Mg co-doping of TiO2 anatase (101) surfaces are studied. By studying the formation energy of the defects and the bond length distribution of the surface, it is shown that Mg defects tend to stay as far as possible to induce least possible lattice distortion while Nb and Mg defects stay close to each other to cause less stress to the surface. By investigating band structure of the surface and changes stemmed from the defects, potential effects of Mg and Mg-Nb co-doping of TiO2 surface on dye-sensitized solar cells are investigated. In this study, it is shown that the Nb-Mg co-doping could increase JSC of the surface while slightly decreasing VOC compared to Mg doped surface, which might result in an increase in efficiency of the DSSCs compared to Nb or Mg doped surfaces.

  2. Synthesis kinetics of Mg_2Sn in Mg-Sn powder mixture using non-isothermal differential scanning calorimetry

    WU Yu-feng; DU Wen-bo; ZUO Tie-yong


    The non-isothermal heating process of Mg-Sn powder mixture was studied by differential scanning calorimetry(DSC) technique and the synthesis kinetics of Mg_2Sn was evaluated by the model-free and model-fitting methods. The activation energy and conversion function of Mg_2Sn synthesis reaction are calculated to be 281.7 kJ/mol and g(α)=[-ln(1-α)]~(1/4), respectively. The reaction mechanism of 2Mg+Sn→Mg_2Sn under non-isothermal condition is regarded as "nucleation and growth". During the non-isothermal heating process, the phase transformation occurred in the Mg-Sn powder mixture was analyzed by XRD and the microstructure evolution of Mg_2Sn was observed by optical microscopy, which is in good agreement with the reaction mechanism of 2Mg+Sn→Mg_2Sn deduced from the kinetic evaluation.

  3. Performance of Mg-14Li-1Al-0.1Ce as anode for Mg-air battery

    Ma, Yibin; Li, Deyu [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Li, Ning [School of Chemical Engineering and Technology, Harbin Institute of Technology, West Street No. 92, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China); Zhang, Milin; Huang, Xiaomei [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001 (China)


    In this research, a new Mg-air battery based on Mg-14Li-1Al-0.1Ce was prepared and the battery performance was investigated by constant current discharge test. The corrosion behavior of Mg, AZ31 and Mg-Li-Al-Ce were studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The characteristics of Mg-Li-Al-Ce after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that Mg-Li-Al-Ce is more active than Mg and AZ31. The self-corrosion rate is found to be in the order: Mg-Li-Al-Ce < Mg < AZ31. It has been observed that the Mg-air battery based on Mg-Li-Al-Ce offers higher operating voltage, anodic efficiency and capacity than those with Mg and AZ31. SEM and EIS results show that the discharge product of Mg-Li-Al-Ce is loosely adhered to the alloy surface, and thus Mg-Li-Al-Ce could keep high discharge activity during discharge. (author)

  4. Understanding and Enhancing Hydrogen Diffusion in MgH2 and NaMgH3

    Sholl, David; Hao, Shiqiang


    The transport properties of hydrogen in metal hydrides are crucial to the kinetics of H2 storage in these materials. We use first-principles calculations to identify the defects that are relevant for H transport in MgH2 and NaMgH3. In both materials, the physically relevant defects are charged and H diffusion is dominated by mobility of negatively charged interstitial H. Interestingly, the diffusion of these species occurs via concerted mechanisms with low energy barriers. To improve the charged interstitial H diffusivity, a series of transition-metal additives are screened to lower the formation energy of mobile defects. Our results provide a practical way to examine and alter H diffusion in light metal hydrides.

  5. Secondary ageing in an Al-Cu-Mg alloy with high Cu/Mg ratio

    Dupasquier, A.; Folegati, P. [Politecnico di Milano (Italy). Ist. di Fisica della Materia; Ferragut, R. [Politecnico di Milano (Italy). Ist. di Fisica della Materia; IFIMAT, Univ. Nacional del Centro de la Provincia de Buenos Aires and CICPBA, Tandil (Argentina); Massazza, M.; Riontino, G. [Ist. Nazionale di Fisica della Materia, Dipt. di Chimica I.F.M., Univ. di Torino (Italy); Somoza, A. [IFIMAT, Univ. Nacional del Centro de la Provincia de Buenos Aires and CICPBA, Tandil (Argentina)


    The mechanisms governing secondary ageing (structural transformations occurring at low temperature after a heat treatment at higher temperature) were investigated by combined measurements of positron lifetimes, Vickers microhardness measurements and differential scanning calorimetry (DSC) on a laboratory alloy (Al-4.5 wt.% Cu-0.56 wt.% Mg). The results show that hardening occurs at a much slower rate than in case of primary ageing at RT. The positron lifetime data suggest that the hardening rate is controlled by slow release of vacancies from Cu-rich clusters formed during the initial high temperature treatment. The hardening stage is concomitant with an increase of the positron lifetime, and has probably the same origin, which is the formation of solute clusters containing vacancies and Mg as essential components. The formation at low temperature of new structures is also demonstrated by DSC. (orig.)

  6. Room-temperature perpendicular magnetic anisotropy of MgO/Fe/MgO ultrathin films

    Kozioł-Rachwał, A.; Ślęzak, T.; Przewoźnik, J. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Skowroński, W.; Stobiecki, T. [Department of Electronics, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Wilgocka-Ślęzak, D. [Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland); Qin, Q. H.; Dijken, S. van [NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Korecki, J. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków (Poland); Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland)


    We used the anomalous Hall effect to study the magnetic properties of MgO/Fe(t)/MgO(001) structures in which the Fe thickness t ranged from 4 Å to 14 Å. For the iron deposited at 140 K, we obtained perpendicular magnetization at room temperature below the critical thickness of t{sub c} = (9 ± 1) Å. In the vicinity of t{sub c}, the easy magnetization axis switched from an out-of-plane orientation to an in-plane orientation, and the observed spin-reorientation transition was considered in terms of the competition among different anisotropies. The perpendicular magnetization direction was attributed to magnetoelastic anisotropy. Finally, the temperature-dependent spin-reorientation transition was analyzed for Fe thicknesses close to t{sub c}.

  7. Transition of interface oxide layer from porous Mg(OH)2 to dense MgO induced by polyaniline and corrosion resistance of Mg alloy therefrom

    Luo, Yizhong; Sun, Yang; Lv, Jinlong; Wang, Xianhong; Li, Ji; Wang, Fosong


    The feasibility of polyaniline emeraldine base (EB) for enhancing long-term corrosion resistance of magnesium alloy (AZ91D Mg alloy) was confirmed, since the complex impedance of Mg alloy protected by EB/epoxy resin (ER) composite coating with 10 wt% EB loading maintained around 2 GΩ cm2 even after 80 day exposure in 0.5 M NaCl solution, while that of pure ER coated analogue decreased to 0.17 MΩ cm2 only after 31 days. The improvement in corrosion resistance was attributed to the transition of interface layer from porous Mg(OH)2 dominated one underneath pure ER coating to dense MgO dominated one underneath EB/ER coating, induced by the redox interaction of EB with Mg alloy. When the EB loading in EB/ER coating increased from 0 to 10 wt%, the relative XPS peak area ratio of MgO to Mg(OH)2 increased from 0.78 to 1.18, indicating that EB behaved as effective corrosion inhibitor causing the transformation of oxide layer from porous Mg(OH)2 to dense MgO.

  8. [Fluconazole 1200mg or 800mg for cryptococcal meningitis treatment in Ivory Coast].

    Kouakou, G A; Ello, N F; Kassi, N A; Keita, M; Doumbia, A; Mossou, C; Kassi, F K; Tanon, A; Ehui, E; Eholié, S P


    Assessing the use of high-dose fluconazol monotherapy (1200mg or 800mg) in the treatment and prognosis of HIV-associated cryptococcal meningitis in Ivory Coast. A retrospective study carried out from August 2008 to August 2011 based on patients charts suffering from CM in the Abidjan Tropicals and Infectious Disease Unit. Mortality rate and associated factors were analyzed. Forty-six cases of cryptococcal meningitis (2.5% of hospitalizations) were included. The sex-ratio was of 1.2. The median age was 40.5 [35-47] years. The symptomatology was subacute (93.5%). The main clinical symptoms were syndrome of pure meningeal irritation (65%), fever (100%); 35% of patients had encephalomeningits. Twenty-one (45.7%) was ART-naïve patients. Fluconazole 1200mg was prescribed to 29 (63%) patients. Therapeutic lumbar punctures were performed in 42 (91.3) patients. The mortality rate was 50%. Significant predictors of mortality were encephalomeningitis and therapeutic lumbar puncture. Cryptococcal meningitis associated mortality remains high despite the use of high-dose fluconazole monotherapy. Therapeutic lumbar punctures help to improving the prognosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Combinatorial search for hydrogen storage alloys: Mg-Ni and Mg-Ni-Ti

    Oelmez, Rabia; Cakmak, Guelhan; Oeztuerk, Tayfur [Dept. of Metallurgical and Materials Engineering, Middle East Technical University, 06531 Ankara (Turkey)


    A combinatorial study was carried out for hydrogen storage alloys involving processes similar to those normally used in their fabrication. The study utilized a single sample of combined elemental (or compound) powders which were milled and consolidated into a bulk form and subsequently deformed to heavy strains. The mixture was then subjected to a post annealing treatment, which brings about solid state reactions between the powders, yielding equilibrium phases in the respective alloy system. A sample, comprising the equilibrium phases, was then pulverized and screened for hydrogen storage compositions. X-ray diffraction was used as a screening tool, the sample having been examined both in the as processed and the hydrogenated state. The method was successfully applied to Mg-Ni and Mg-Ni-Ti yielding the well known Mg{sub 2}Ni as the storage composition. It is concluded that a partitioning of the alloy system into regions of similar solidus temperature would be required to encompass the full spectrum of equilibrium phases. (author)

  10. Preparation of 24Mg-Fe-Cu Target

    FAN; Qi-wen; DU; Ying-hui; ZHANG; Rong


    <正>The three-layer-sandwich targets of 24Mg-Fe-Cu needed to be prepared in the physics experiment. The middle layers are thin ferromagnetic Fe layers of about 3.2 mg/cm2. The recoil stopper layers are thick crystallized and defect-free Cu layers of about 15 mg/cm2. The thickness of the 24Mg target layers is about 300 μg/cm2, and the uniformity should be better than 90%.

  11. A Fast Liquid Chromatography Tandem Mass Spectrometric Analysis of PETN (Pentaerythritol Tetranitrate), RDX (3,5-Trinitro-1,3,5-triazacyclohexane) and HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) in Soil, Utilizing a Simple Ultrasonic-Assisted Extraction with Minimum Solvent.

    Anilanmert, Beril; Aydin, Muhammet; Apak, Resat; Avci, Gülfidan Yenel; Cengiz, Salih


    Direct analyses of explosives in soil using liquid chromatography tandem mass spectrometry (LC-MS/MS) methods are very limited in the literature and require complex procedures or relatively high amount of solvent. A simple and rapid method was developed for the determination of pentaerythritol tetranitrate (PETN), 3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), which are among the explosives used in terrorist attacks. A one-step extraction method for 1.00 g soil with 2.00 mL acetonitrile, and a 8-min LC-MS/MS method was developed. The detection limits for PETN, RDX and HMX were 5.2, 8.5 and 3.4 ng/g and quantitation limits were 10.0, 24.5, 6.0 ng/g. The intermediate precisions and Horwitz Ratio's were between 4.10 - 13.26% and 0.24 - 0.98, in order. This method was applied to a model post-blast debris collected from an artificial explosion and real samples collected after a terrorist attack in Istanbul. The method is easy and fast and requires less solvent use than other methods.

  12. Synthesis of {sup 14}C-labelled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), nitrocellulose (NC) and glycidyl azide polymer (GAP) for use in assessing the biodegradation potential of these energetic compounds

    Ampleman, G.; Thiboutot, S.; Lavigne, J.; Marois, A. [Defence Research Establishment Valcartier, Courcelette, PQ (Canada); Hawari, J.; Jones, A.M.; Rho, D. [National Research Council of Canada, Ottawa, ON (Canada)


    Within the framework of an R and D project on bioremediation of soils contaminated with energetic compounds, the biodegradation of energetic products such as hexogen (RDX), trinitrotoluene (TNT), nitrocellulose (NC) and glycidyl azide polymer (GAP) is under study. Microcosm assays must be performed with radioactive carbon-14 labelled products in order to follow the biodegradation process. {sup 14}C-RDX was prepared by nitration of hexamethylenetetramine (HMTA) according to the Hale process. {sup 14}C-ring and methyl labelled TNTs synthesized according to the Dorey and Carper procedure. {sup 14}C-cellulose was synthesized from {sup 14}C-glucose by Acetobacter xylinum. Nitration of the {sup 14}C-cellulose yielded {sup 14}C-nitrocellulose. {sup 14}C-glycidyl azide polymer was obtained by polymerization and azidation of {sup 14}C-epichlorohydrin (ECH) which was synthesized from {sup 14}C-glycerol. Hydrochlorination of {sup 14}C-glycerol and epoxidation of the resulting {sup 14}C-1,3-dichloro 2-propanol yielded {sup 14}C-ECH. The syntheses of these {sup 14}C-labelled explosives are described in this paper. (Author).

  13. MgB2 tunnel junctions and SQUIDs

    Brinkman, A.; Rowell, J.M.


    Recent advances in the realization and understanding of MgB2 tunnel junctions and SQUIDs are surveyed. High quality MgB2 junctions with suitable tunnel barriers have been realized based on both oriented and epitaxial thin MgB2 films. Multiband transport properties, such as the existence of two energ

  14. Hydrogen absorption and desorption in rapidly solidified Mg- Al alloys

    Urgnani, J.; Di Chio, M.; Palumbo, M.; Feuerbacher, M.; Fernandez, J. F.; Leardini, F.; Baricco, M.


    The addition of Al to Mg has been indicated as a suitable way to destabilise the hydride phase, in order to bring the absorption and desorption reactions close to reasonable temperatures and pressure values for hydrogen storage. Rapid solidification is known to refine the microstructure of Mg-Al alloys and it might improve the H2 absorption/desorption kinetics. In this paper, the interaction of H2 with rapidly solidified Mg-Al alloys have been studied for three different composition: Mg38.5Al61.5, Mg69Al31 and Mg72Al28. For Mg72Al28, no significant changes in the microstructure have been obtained by rapid solidification. In Mg69Al31, a significant grain refinement has been observed, whereas, for Mg38.5Al61.5, the formation of a metastable hexagonal phase has been found. In all cases, a disproportionation reaction has been observed after H2 absorption, leading to MgH2. After heating up to 430 °C the hydrogenated samples, a main desorption reaction from MgH2 has been observed, which brings again to the starting phases. Experimental results have been discussed on the basis of a thermodynamic assessment of the Mg-Al-H system.

  15. Thermodynamic assessment of the Bi-Mg binary system

    Chunju NIU; Changrong LI; Zhenmin DU; Cuiping GUO; Yongjuan JING


    The Bi-Mg binary system had been assessed by adopting the ionic melt and the modified quasi-chemical models to describe the liquid phase with short range ordering behavior.In general considerations of the development of the thermodynamic database of the multi-component Mg-based alloys and the consistency of the thermodynamic models of the related phases,the Gibbs energy descriptions of all the phases in the Bi-Mg binary system were reasonably re-modeled and critically re-assessed in the present work.Especially for the liquid phase,the associate model was used with the constituent species Bi,Mg and Bi2Mg3.The Mg-rich terminal phase hcp_A3 was modeled as a substitutional solution following Redlich-Kister equation and the Bi-rich terminal phase Rhombohedral_A7 was treated as a pure Bi substance since the extremely small solubility of Mg in Bi. The low and high temperature nonstoichiometric compounds β-Bi2Mg3 and α-Bi2Mg3 were described by the sublattice models (Bi,Va)2Mg3 and (Bi)1 (Bi,Va)aMg6 respectively based on their structure features.A set of self-consistent thermodynamic parameters of the Bi-Mg system was obtained and the experimental thermodynamic and phase equilibrium data were well reproduced by the optimized thermodynamic data.

  16. Hydrogen absorption and desorption in rapidly solidified Mg- Al alloys

    Urgnani, J; Di Chio, M; Palumbo, M; Baricco, M [Dipartimento di Chimica I.F.M. and NIS, Universita di Torino, via P. Giuria, 10125, Torino (Italy); Feuerbacher, M [Institut fuer Mikrostrukturforschung, Forschungszentrum Juelich GmbH, Leo-Brand- Strasse, 52428 Juelich (Germany); Fernandez, J F; Leardini, F, E-mail: jacopo.urgnani@unito.i [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Cantoblanco, 28049, Madrid (Spain)


    The addition of Al to Mg has been indicated as a suitable way to destabilise the hydride phase, in order to bring the absorption and desorption reactions close to reasonable temperatures and pressure values for hydrogen storage. Rapid solidification is known to refine the microstructure of Mg-Al alloys and it might improve the H{sub 2} absorption/desorption kinetics. In this paper, the interaction of H{sub 2} with rapidly solidified Mg-Al alloys have been studied for three different composition: Mg{sub 38.5}Al{sub 61.5}, Mg{sub 69}Al{sub 31} and Mg{sub 72}Al{sub 28}. For Mg{sub 72}Al{sub 28}, no significant changes in the microstructure have been obtained by rapid solidification. In Mg{sub 69}Al{sub 31}, a significant grain refinement has been observed, whereas, for Mg{sub 38.5}Al{sub 61.5}, the formation of a metastable hexagonal phase has been found. In all cases, a disproportionation reaction has been observed after H{sub 2} absorption, leading to MgH{sub 2}. After heating up to 430 deg. C the hydrogenated samples, a main desorption reaction from MgH{sub 2} has been observed, which brings again to the starting phases. Experimental results have been discussed on the basis of a thermodynamic assessment of the Mg-Al-H system.

  17. Cardiovascular effect of dental anesthesia with articaine (40 mg with epinefrine 0,5 mg % and 40 mg with epinefrine 1 mg%) versus mepivacaine (30 mg and 20 mg with epinefrine 1 mg%) in medically compromised cardiac patients: a cross-over, randomized, single blinded study.

    Torres-Lagares, Daniel; Serrera-Figallo, María-Ángeles; Machuca-Portillo, Guillermo; Corcuera-Flores, José-Ramón; Machuca-Portillo, Carmen; Castillo-Oyagüe, Raquel; Gutiérrez-Pérez, José-Luis


    The aim of the present study is to compare cardiovascular safety profiles of two dental anesthetics: articaine versus two standard mepivacaine solutions used during etiological periodontal treatment in cardiovascular patients. Using a cross-over study design, ten cardiovascular patients were randomly assigned to dental treatment with 1.8 mL of a local anesthetic injected on each quadrant of the mouth: Articaine (40 mg with Epinephrine 0.5 mg % and 40 mg with Epinephrine 1mg %) or Mepivacaine (30 mg and 20 mg with Epinephrine 1mg %). A computer programme enabled continuous longitudinal data collection: O2 saturation, blood pressure (BP) and heart rate (HR). No severe clinical side effects were observed. During the treatment period, we observed statistically significant differences as regards HR between injections with and without adrenalin (p< 0.039) and as regards systolic (p< 0.046) and diastolic (p < 0.046) blood pressure during the stabilization period. In both cases, the parameters under study increase. Age, gender, jaw treated, treatment duration and the rest of cardiovascular variables did not affect the results. None of the patients underwent ischemic alterations or any other complication derived from the treatment or the anesthesia. According to the results of our study, dental anesthetics with standard concentrations of Epinephrine seem to alter HR and BP. Although no cardiac ischemic alterations or any other cardiovascular complications have been observed, we must be cautious with the administration of anesthetics containing vasoconstrictors in patients with cardiovascular diseases.

  18. Corrosion Resistance of the Superhydrophobic Mg(OH)2/Mg-Al Layered Double Hydroxide Coatings on Magnesium Alloys

    Zhang, Fen; Zhang, Changlei; Zeng, Rongchang; Song, Liang; Guo, Lian; Huang, Xiaowen


      Coatings of the Mg(OH)2/Mg-Al layered double hydroxide (LDH) composite were formed by a combined co-precipitation method and hydrothermal process on the AZ31 alloy substrate in alkaline condition...

  19. Fabrication of Mg-doped ZnO thin films by laser ablation of Zn:Mg target

    Kim, Tae Hyun; Park, Jin Jae; Nam, Sang Hwan; Park, Hye Sun; Cheong, Nu Ri [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of); Song, Jae Kyu [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of)], E-mail:; Park, Seung Min [Department of Chemistry, Kyunghee University, Seoul 130-701 (Korea, Republic of)], E-mail:


    Mg-doped ZnO thin films were fabricated by laser ablation of Zn:Mg targets consisting of Mg metallic strips and Zn disk in oxygen atmosphere with a goal to facilitate convenient control of Mg contents in the films. The characteristics of the deposited films were examined by analyzing their photoluminescence (PL), X-ray diffraction and X-ray photoelectron spectroscopy (XPS) spectra. Mg contents as analyzed by XPS indicate that the target composition is fairly transferred to the deposited films. The wurtzite structure of ZnO was conserved even for the highly doped ZnO films and there was no Mg- or MgO-related XRD peaks. With increase in the Mg content, the bandgap and PL peak energy shifted to blue and the Stokes shift became larger.

  20. Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg{sub 2}Si/MgB{sub 2} nanocomposites

    Ueno, Katsuya; Takahashi, Kazuyuki; Uchino, Takashi, E-mail: [Department of Chemistry, Graduate School of Science, Kobe University, Nada, Kobe 657-8501 (Japan); Nagashima, Yukihito [Nippon Sheet Glass Co., Ltd., Konoike, Itami 664-8520 (Japan); Seto, Yusuke [Department of Planetology, Graduate School of Science, Kobe University, Nada, Kobe 657-8501 (Japan); Matsumoto, Megumi; Sakurai, Takahiro [Center for Support to Research and Education Activities, Kobe University, Nada, Kobe 657-8501 (Japan); Ohta, Hitoshi [Molecular Photoscience Research Center, Kobe University, Nada, Kobe 657-8501 (Japan)


    Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg{sub 2}Si)/superconductor(MgB{sub 2}) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg{sub 2}Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB{sub 2} nanograins surrounded by the MgO/Mg{sub 2}Si matrix. This transition is followed by the intergrain phase-lock transition at ∼24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a simple process to fabricate dense nanocomposites with high-quality interfaces, but also enables to investigate the electric and magnetic properties of embedded superconducting nanograins with good intergrain coupling.