A review of the mallet impact test for small scale explosive formulations

Presented at 19th Seminar on New Trends of Energetic Materials (NTREM 2016); 20-22/04/2016, Pardubice Czech RepublicDevelopment of new explosive formulations begins with the generation of only a few milligrams of material which is investigated using a number of small scale tests such as DSC, TGA, response to flame, mallet impact (mallet friction either glancing or direct blow) to determine whether the formulation is safe to scale up to 10 g. The latter of these tests, mallet impact, can be particularly subjective as the result is directly influenced by the operator carrying out the assessment. Not only can there be a change from one operator to another but there can also be a change in the force applied during each strike potentially leading to inconsistent results. This study highlights this encountered variation and assesses the load applied by a variety of operators with varying levels of explosive experience. This paper also proposes the use of a small scale laboratory based impact test which would provide improved confidence in the assessment of impact sensitiveness of explosive formulations and assist in justifying whether a formulation can be taken to the next scale. A small scale version of the BAM impact test (EMTAP Test 43) has been devised that allows the comparison of the sensitiveness of small scale formulations relative to RDX (8.7 J, EMTAP Test 43B) whilst also ensuring a reproducible result

Thermodynamics and mechanism of protonated cysteine decomposition: a guided ion beam and computational study

pre-printA quantitative molecular description of the decomposition of protonated cysteine, H+Cys, is provided by studying the kinetic energy dependence of threshold collision-induced dissociation (CID) with Xe using a guided ion beam tandem mass spectrometer (GIBMS). Primary dissociation channels are deamidation (yielding both NH3 loss and NH4 + formation) and (H2O + CO) loss reactions, followed by an additional six subsequent decompositions. Analysis of the kinetic energy-dependent CID cross sections provides the 0 K barriers for six different reactions after accounting for unimolecular decay rates, internal energy of reactant ions, multiple ion-molecule collisions, and competition among the decay channels. To identify the mechanisms associated with these reactions, quantum chemical calculations performed at the B3LYP/6-311+G(d,p) level were used to locate the transition states (TSs) and intermediates for these processes. Single point energies of the reactants, products, and key optimized TSs and intermediates are calculated at B3LYP, B3P86, and MP2(full) levels using a 6-311+G(2d,2p) basis set. The computational characterization of the elementary steps of these reactions including the structures of the final products is validated by quantitative agreement with the experimental energetics. In agreement with previous work, deamidation is facilitated by anchimeric assistance of the thio group, which also leads to an interesting rearrangement of the intact amino acid identified computationally

Mid-adolescent ethnic variations in overweight prevalence in the UK Millennium Cohort Study

BACKGROUND: There are stark ethnic inequalities in the prevalence of UK childhood obesity. However, data on adolescent overweight in different ethnic groups are limited. This study assessed ethnic inequalities in overweight prevalence during mid-adolescence using body mass index (BMI) and explored the contribution of socioeconomic and behavioural factors. METHODS: We analyzed data from 10 500 adolescents aged between 13 and 15 years who participated in sweep six of the Millennium Cohort Study. Ethnic inequalities in overweight and mean BMI were assessed using multiple regression models. Results were stratified by sex and adjusted for socioeconomic and behavioural factors. RESULTS: Black Caribbean males had significantly higher BMI than White males after full adjustment [excess BMI 2.94, 95% confidence interval (CI) 0.70-5.19] and were over three times more likely to be overweight [odds ratio (OR): 3.32, 95% CI 1.95-5.66]. Black Africans females had significantly higher BMI compared with White females (excess BMI 1.86, 95% CI 0.89-2.83; OR for overweight 2.74, 95% CI 1.64-4.56), while Indian females had significantly lower BMI compared with White females (reduced BMI -0.73, 95% CI -1.37 to -0.09). Socioeconomic and behavioural factors often considered to be associated with overweight were more prevalent in some ethnic minority groups (lower socioeconomic position, lack of breakfast consumption, low fruit and vegetable intake, high sugar-sweetened beverage and fast-food consumption, and infrequent physical activity), but adjustment for these factors did not fully explain ethnic differences in overweight/BMI. CONCLUSION: Ethnic inequalities in overweight prevalence are evident in mid-adolescence and vary according to sex. Differences in overweight/BMI between ethnic groups were not fully accounted for by socioeconomic or behavioural factors

Informal Caregivers’ Experiences of Caring for Older Adults Diagnosed with Urinary Tract Infections

Informal caregivers’ experiences of caring for older adults diagnosed with a urinary tract infection (UTI) is a prevalent issue that affects adults as they age. The purpose of this generic qualitative study was to understand informal caregivers’ experiences observing and reporting to doctors observable changes of behavior in older adults that were later linked to unconventional symptoms of potential UTIs. Attribution theory was used as the theoretical framework for this study. This qualitative study addressed the research question of informal caregivers’ experiences observing and reporting to doctors observed changes in older adults associated with unconventional UTI symptoms. Data were collected from six African American women over the age of 18 years old with experience as informal caregivers through semi-structured, audio-recorded phone and face-to-face interviews. The data were analyzed using Moustakas’s method to determine the themes. Findings revealed that the participants were people who cared and advocated for their patients. Findings also revealed key thematic response categories, such as key symptoms of UTIs observed and reported by caregivers and experiences communicating with medical professionals. This study serves as a call for more research to be conducted related to informal caregivers’ experience caring for older adults diagnosed with UTIs. This study’s implications for positive social change include the potential use by human services professionals, social workers, and advocates to advocate for educational seminars and awareness campaigns that educate informal caregivers on some of the atypical or unconventional symptoms of UTIs

Solution composition and particle size effects on the dissolution and solubility of a ThO2 microstructural analogue for UO2 matrix of nuclear fuel

The objective of this study was to investigate the dissolution rate of ThO2 which was synthesised to approximate, as closely as possible, the microstructure of UO2 in a nuclear fuel matrix. The optimal sintering temperature for ThO2 pellets was found to be 1750 ℃, which produced pellets with a microstructure similar to UO2 nuclear fuel pellets, with randomly oriented grains ranging in size from 10 to 30 μm. Dissolution was conducted using ThO2 particles of different size fractions (80 to 160 μm and 2 to 4 mm) in the presence and absence of carbonate, in solutions with pH from 2 to 8 and at 80 ℃. Dissolution rates were calculated from Th released from the solid phase to solution. Particles of ThO2 were also leached with 1 M HNO3 at 80 ℃ in order to investigate the morphological changes at the particle surfaces. The concentration of Th was found to be ≥ 10–9 mol/L at pH ≤ 4, lower than the theoretical solubility of crystalline ThO2. At higher pH values, from 4 to 8, the measured concentrations (10−10 to 10–12 mol/L) were between the theoretical solubility of ThO2 and Th(OH)4. Grain boundaries were shown to exert an influence on the dissolution of ThO2 particles. Using high resolution aqueous solution analysis, these data presented here extend the current understanding of Th solubility in solutio

The meaning of exercise and physical activity in community dwelling people with multiple sclerosis

Copyright © 2018 The Author(s). Purpose This study explored the meanings community dwelling people with Multiple Sclerosis ascribe to exercise and physical activity. Method Using a qualitative approach, 16 face-to-face, semi-structured interviews were conducted. Data were analysed using Framework Analysis and emerging themes developed. Results Five themes were identified: “A Type of Movement”, “The Impact of Exercise and Physical Activity”, “It Changes”, “Sense of Loss” and “Coping with Multiple Sclerosis”. The findings demonstrated that people with multiple sclerosis held a multidimensional and complex view about exercise and physical activity. Conclusion The meanings people with multiple sclerosis ascribe to exercise and physical activity extended beyond movement, reflecting how they lived with a variable neurological condition. Personal and contextual factors were dominant influences

A Qualitative exploration of physiotherapists' perceptions about exercise and physical activity: Reflections on the results from a Delphi Study

Purpose: This study explored physiotherapists’ interpretation of exercise and physical activity, examined physiotherapists’ views and opinions about the prioritised physical activity practices of people with multiple sclerosis and its implication for clinical practice. Method: Fourteen physiotherapists (12 females, 2 males) with experience of working with people with multiple sclerosis in the community participated in three focus groups. Physiotherapists commented on the results of a previous Delphi study which highlighted the prioritised exercise and physical activity practices and reasons people with multiple sclerosis engage in exercise and physical activity. The focus groups were audio recorded and transcribed verbatim. Data were analysed using framework analysis. Results: Four themes were developed from the analysis namely, Blurred terminologies, Influencing factors for the meaning of exercise and physical activity, When professional expertise meets experiential expertise and The resolve: resolving professional and experiential tensions. Conclusion: Physiotherapists described exercise and physical activity as movement with a focus on the physiological attributes. Nonetheless they valued and use exercise and physical activity as strategies to manage the symptoms associated with multiple sclerosis. Physiotherapists are strategically placed in the community to initiate discussions, assess, and create opportunities to enhance the physical activity practices of people with multiple sclerosis. However, there is greater scope for the application of physical activity to be embedded in routine clinical practice in the management of multiple sclerosis in the community. Implications for rehabilitation Physiotherapists should design flexible physical activity programmes which are meaningful, engaging and foster the necessary environment to sustain physical activity participation in people with multiple sclerosis. Health professionals should be aware of and understand the individuals’ priorities as these are key drivers to engaging and sustaining physical activity in community dwelling people with multiple sclerosis. Physiotherapists should be aware of their own beliefs and theoretical principles that guide designs and treatment programmes as these might either enhance or restrict physical activity in people with multiple sclerosis

Synthesis and characterization of iodovanadinite using PdI2, an iodine source for the immobilisation of radioiodine

The synthesis of a palladium-containing iodovanadinite derivative, hypothetically “PdPb9(VO4)6I2”, was attempted using PdI2 as a source of iodine in searching for a novel waste form for radioiodine. Stoichiometric amounts of Pb3(VO4)2 and PdI2 were batched and reacted at elevated temperatures in sealed vessels. Batched material was also subjected to high-energy ball-milling (HEBM) in order to reduce reaction time and the potential for iodine volatilization during subsequent reaction at 200–500 °C. The resulting products were characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, IR spectroscopy, thermal analysis and Pd K XANES. Results showed that PdI2 can function as a sacrificial iodine source for the formation of iodovanadinite, prototypically Pb10(VO4)6I2, however, the incorporation of Pd into this phase was not definitively observed. The sacrificial reaction mechanism involved the decomposition of PdI2 to Pd metal and nascent I2, with the latter incorporated into the iodovanadinite Pb10(VO4)6I2 phase. In comparison to processing using standard solid state reaction techniques, the use of HEBM prior to high temperature reaction generates a more homogeneous end-product with better iodine retention for this system. Overall, the key novelty and importance of this work is in demonstrating a method for direct immobilisation of undissolved PdI2 from nuclear fuel reprocessing, in a composite wasteform in which I-129 is immobilised within a durable iodovandinite ceramic, encapsulating Pd metal

Evolution of phase assemblage of blended magnesium potassium phosphate cement binders at 200 degrees and 1000 degrees C

The fire performance of magnesium potassium phosphate cement (MKPC) binders blended with fly ash (FA) and ground granulated blast furnace slag (GBFS) was investigated up to 1000°C using X-ray diffraction, thermogravimetric analysis and SEM techniques. The FA/MKPC and GBFS/MKPC binders dehydrate above 200°C to form amorphous KMgPO4, concurrent with volumetric and mass changes. Above 1000°C, additional crystalline phases were formed and microstructural changes occurred, although no cracking or spalling of the samples was observed. These results indicate that FA/MKPC and GBFS/MKPC binders are expected to have satisfactory fire performance under the fire scenario conditions relevant to the operation of a UK or other geological disposal facility

A preliminary investigation of the molten salt mediated synthesis of Gd2TiO5 ‘stuffed’ pyrochlore

Refractory ‘stuffed’ pyrochlores such as Gd2TiO5 are of interest for nuclear applications, including as matrices for actinide disposition and as neutron absorbers in control rods. Here, we report the results of a preliminary comparative investigation of the synthesis of Gd2TiO5 by molten salt and conventional solid-state synthesis. We show that synthesis of Gd2TiO5 proceeds from the pyrochlore phase Gd2Ti2O7 which is first formed as a kinetic product. Molten salt synthesis afforded single phase Gd2TiO5 at 1300 °C in 2 h, via a template growth mechanism, and is effective for the synthesis of these refractory materials. This work demonstrates molten salt mediated synthesis of ‘stuffed’ pyrochlore for the first time