CERES :: Browsing by Author "Ladyman, Melissa K."

Browsing by Author "Ladyman, Melissa K."

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Open Access
Adsorption behaviour of 1,3,5-trinitroperhydro-1,3,5-triazine, 2,4-dinitroanisole and 3-nitro-1,2,4-triazol-5-one on commercial activated carbons
(Elsevier, 2020-04-30) Fawcett-Hirst, William; Temple, Tracey J.; Ladyman, Melissa K.; Coulon, Frederic
Insensitive high explosives are increasingly being used to replace more sensitive formulations, however large quantities of environmentally hazardous wastewater are generated from loading, assembling and packing processes. Currently, there is limited literature regarding the treatment of wastewater contaminated with these hazardous insensitive high explosive materials such as 1,3,5-trinitroperhydro- 1,3,5-triazine (RDX), 2,4-dinitoranisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO). The preferred method of explosive wastewater treatment is adsorption by activated carbon, usually through treatment columns or fluidised beds that are simple to operate and cost effective. The aim of this research was to assess whether commercially available activated carbons would be suitable and economically viable to treat explosive wastewater containing RDX, DNAN and NTO. Bottle point tests were used to determine adsorption capacity and adsorption kinetics for the individual insensitive high explosives with three different activated carbons. Equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherms to determine the mechanisms of adsorption. Six hour bottle point tests for a mixture of the three insensitive high explosive constituents were used to consider possible preferential adsorption. As expected, RDX and DNAN were adsorbed at concentrations up to 40 mg.L-1 and 150 mg.L-1 respectively by the activated carbons tested, demonstrating the viability of treatment by adsorption. However, at the high concentrations of NTO expected in wastewater (1400 mg.L-1) activated carbons were rapidly saturated, suggesting that treatment of NTO contaminated wastewater would require prohibitively large quantities of activated carbon compared to RDX and DNAN.
Open Access
Assessing the performance of environmental management in academic research laboratories
(Elsevier, 2022-03-23) Ladyman, Melissa K.; Gutierrez Carazo, Encina; Persico, Federica; Temple, Tracey J.; Coulon, Frederic
Managing environmental risk is essential to ensure organisations minimise their impact on the environment, comply with environmental legislation and maintain their reputation in an increasingly environmentally aware society. Organisations frequently use management systems to plan and execute routine environmental assessments, however environmental impacts may still arise from routine activities or accidents that could be avoided by effective environmental management. Currently there is no method for an organisation to assess the level of awareness their employees have of activities that may lead to an environmental impact, or the level of uptake of environmental management processes. Therefore, the Environmental Management Performance Assessment (EMPA) process was developed to enable organisations to self-assess existing environmental management processes by survey of their employees. The EMPA process was aligned to key phases of the Deming Cycle and involves development and distribution of a survey to organisation employees. The responses are then used to recognise areas for improvement by progression through a bespoke flow chart integrated with the initial survey. This enables demonstration of how particular hazards arise from insufficient awareness at different stages in the Deming Cycle and how these hazards can have wider, reputational, economic, and legislative consequences. The process was trialled by surveying academic researchers on the environmental management processes in their laboratories as a sample set.
Open Access
Decision framework for the environmental management of explosive contaminated land
(Elsevier, 2019-07-04) Ladyman, Melissa K.; Temple, Tracey J.; Piperakis, Michael; Fawcett-Hirst, William; Gutierrez-Carazo, Encina; Coulon, Frederic
The environmental risks from explosive manufacturing and testing activities are usually evaluated using a qualitative process such as environmental impact prioritisation as recommended by legislation and guidance. However, standard environmental management system (EMS) guidance rarely provides detailed information on how to objectively assess the significance of the environmental impacts based on a rational scientific evidence. Quantitative exposure and eco-toxicity assessments are frequently used in combination with environmental threshold limit guidelines, but these omit important environmental impacts such as physical damage to land, nuisance and contribution to climate change. These impacts are particularly relevant to the explosives industry where noise nuisance and physical damage are given high priority. In addition, contamination from explosive compositions may comprise mixtures of multiple legacy and new generation explosives such as 1,3,5-trinitro-1,3,5-triazinane (RDX), 2,4,6-trinitrotoluene (TNT), 5-nitro-1,2,4-triazol-3-one (NTO), 2,4-dinitroanisole (DNAN) and nitroguandine (NQ), which may have combined impacts not captured by conventional eco-toxicity assessments. Further, threshold limits for energetic materials in soil and water have not been established for most nations. Additionally, in the explosive industry wider concerns such as legislative compliance and stakeholder concerns may help to provide a more broadly applicable assessment of environmental impact. Therefore in this study a novel decision framework was developed to integrate empirical data with business risks to enable rational decision making for the environmental management of explosive manufacturing facilities. The application of the framework was illustrated using three case studies from the explosive manufacturing industry to demonstrate how the framework can be used to justify environmental management decision making. By linking the environmental impacts to business risks, we demonstrate that manufacturers are able to assess a wide spectrum of issues that might not be identified in the initial environmental assessment such as non-toxic pollution incidents, breaches in legislation and stakeholder perceptions.
Open Access
The effect of soil type on the extraction of insensitive high explosive constituents using four conventional methods
(Elsevier, 2019-03-01) Temple, Tracey J.; Cipullo, S.; Galante, Erick; Ladyman, Melissa K.; Mai, Nathalie; Parry, T.
Explosive contamination is commonly found at military and manufacturing sites (Hewitt et al., 2005; Clausen et al., 2004; Walsh et al., 2013). Under current environmental legislation the extent of the contamination must be characterized by soil sampling and subsequent separation of the explosive contaminants from the soil matrix by extraction to enable chemical analysis and quantification (Dean, 2009). It is essential that the extraction method can consistently recover explosive residue from a variety of soil types i.e. all materials that have not degraded or irreversibly bound to the matrix, so that any resultant risk is not underestimated. In this study, five different soil types with a range of organic content, particle size and pH, were spiked with a mixture of RDX, DNAN, NQ and NTO at 50 mg/kg and were extracted using one of four one-step extraction methods: stirring, shaking, sonication, and accelerated solvent extraction (ASE). Analysis of the extraction efficiencies of the four methods found that they were broadly successful for the extraction of all IHE constituents from all five soils (an average of 84% ± 14% recovery across 80 extractions). However, soils with high organic content (Total Organic Content (TOC) ≥ 2%) were found to significantly affect extraction efficiency and reproducibility. NTO and DNAN were the least consistent in extraction efficiency with poorest recovery of NTO as low as 37% ± 2%. Of the four tested methods shaking was found to be the most reproducible, though less efficient than stirring (64%–91%). ASE was found to have the most variable results for extraction of IHE constituents suggesting that ASE was the most affected by the different soil types. Therefore, it is recommended that the efficiency and reproducibility of the selected extraction method should be validated by extracting known concentrations of the IHE from the soil of interest and that any required correction factors are reported.
Open Access
Evaluation of small-scale combustion of an insensitive high explosive formulation containing 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)
(Taylor and Francis, 2020-05-25) Galante, Erick B. F.; Mai, Nathalie; Ladyman, Melissa K.; Gill, Philip P.; Temple, Tracey J.; Coulon, Frederic
Energetic materials are often disposed by open-burning or open-detonation as it is a cost-effective and efficient means of destroying explosive material, and often minimizes the need to transport hazardous explosives to treatment facilities. This practice is often scrutinized for the negative environmental impact of the odorous and unsightly toxic gaseous emissions as well as the resulting deposition residues, which often contain unburned energetic materials. With the increasing use of Insensitive High Explosive compositions in munitions, it is essential that the potential environmental impact of their disposal is assessed before their extensive use to prevent the kind of contamination incidents experienced with legacy explosives. Therefore, the aim of this work was to develop a controlled laboratory experiment to identify the gaseous emissions and the energetic material residues that are generated through the combustion of the IHE components 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). A sealed vial containing small (mg) quantities of energetic material was heated until the energetic material combusted. Gas chromatography/mass spectrometry (GCMS) was used to calculate the oxygen consumption and to identify the gases that were generated. The solid residues were analyzed by high-performance liquid chromatography (HPLC) to quantify unburned energetic material. Results showed that DNAN was the most resistant to burning, thus leaving significant quantities of unreacted starting material in the vial. An interesting observation for the IHE formulation was that DNAN also inhibited the combustion of NTO and RDX. The gases emitted during the open burning of IHE components and mixtures included CO, CO2, and N2O as expected, but the proportions differed when the components and mixture were compared, reflecting the influence of DNAN on the burning behavior. From our data, we concluded that open-burning DNAN-based formulations is an environmentally unfavorable waste-management practice for the disposal of IHEs mainly due to generation of solid residues as well as unburnt DNAN.
Open Access
Fluorescent formazans and tetrazolium salts – towards fluorescent cytotoxicity assays
(2016-07-11) Ladyman, Melissa K.; Walton, J. G. A.; Lillenkampf, A.; Bradley, M.
Formazan-based colorimetric cytotoxicity assays, such as the MTT assay, are typically used to assess cell viability with only metabolically active cells reducing tetrazolium salts into the formazans, which is then quantified by absorbance. Fluorescence offers several advantages compared to colorimetric assays and would enable techniques such as flow cytometry and confocal microscopy to be used for analysis. Here, fluorescent formazans 10, 11 and 12, and their corresponding tetrazolium salts 13, 16 and 24, respectively, were synthesised by incorporation of a known fluorophore backbone (coumarin, fluorescein and rhodol) with disruption of the conjugated system preventing or reducing fluorescence of the tetrazolium salts. The tetrazolium moiety was able to quench the fluorescence of the incorporated fluorescein and O-methyl rhodol, whereas with the coumarin-based tetrazolium salt the fluorescence was only quenched under acidic conditions. These tetrazolium salts were successfully reduced to the fluorescent formazans with cells and offer a step forward in the development of fluorescent cytotoxicity assays.
Open Access
Investigation into the environmental fate of the combined Insensitive High Explosive constituents 2, 4-dinitroanisole (DNAN), 1-nitroguanidine (NQ) and nitrotriazolone (NTO) in soil
(Elsevier, 2018-01-12) Temple, Tracey J.; Ladyman, Melissa K.; Mai, Nathalie; Galante, Erick; Ricamora, M; Shirazi, R; Coulon, Frederic
Contamination of military ranges by the use of explosives can lead to irreversible environmental damage, specifically to soil and groundwater. The fate and effects of traditional explosive residues are well understood, while less is known about the impact of Insensitive High Explosives (IHEs) that are currently being brought into military service. Current research has focussed on the investigation of individual constituents of IHE formulations, which may not be representative of real-world scenarios when explosive residues will be deposited together. Therefore, this study investigated the fate and transport of the combined IHE constituents 2,4-dinitroanisole (DNAN), 1-nitroguanidine (NQ) and 3-nitro-1,2,4-triazol-5-one (NTO) in two UK soil types. Static experiments ran for 9 weeks to determine the fate of the combined explosive constituents in soil by monitoring the rate of degradation. Transport was examined by running soil column experiments for 5 weeks, with a watering regime equivalent to the average yearly UK rainfall. Both static and soil column experiments confirmed that DNAN and NTO started to degrade within twenty-four hours in soil with high organic content, and were both completely degraded within sixty days. NQ was more stable, with 80% of the original material recovered after sixty days. The major degradation product of DNAN in the test soils was 2-amino-4-nitroanisole (2-ANAN), with trace amounts of 4-amino-2-nitroanisole. NTO was rapidly degraded in soil with high organic content, although no degradation products were identified. Results supported work from literature on the individual constituents DNAN, NQ and NTO suggesting that the three explosives in combination did not interact with each other when in soil. This study should provide a useful insight into the behaviour of three combined Insensitive High Explosive constituents for the predication of soil and water contamination during military training.
Open Access
Investigation of energetic particle distribution from high-order detonations of munitions
(Wiley - VCH Verlag, 2017-06-08) Walsh, M. R.; Temple, Tracey J.; Big, M. F.; Tshabalala, S. F.; Mai, N.; Ladyman, Melissa K.
Military training with munitions containing explosives will result in the deposition of energetic materials on ranges. These residues contain compounds that may result in human health impacts when off-range migration occurs. Models exist that predict the spatial and mass distribution of particles, but they have proven to be difficult to apply to detonating munitions. We have conducted a series of tests to determine if modelling results can be directly applied to simple detonation scenarios. We also command detonated several rounds to obtain an initial indication of high-order detonation particle distributional heterogeneity. The detonation tests indicate that particle distributions will be quite heterogeneous and that the model used did not adequately describe the distribution of detonation residues. This research will need to be expanded to build an empirical database sufficient to enable the refinement of existing models and improve their predictions. Research on low-order detonations should be conducted as low-order detonations will result in higher mass deposition than high-order detonations. Distribution models verified with empirical data may then be incorporated into range management models.
Open Access
Optimised accelerated solvent extraction of hexahydro‐1, 3, 5‐trinitro‐1, 3, 5 triazine (RDX) from polymer bonded explosives
(Wiley, 2018-10-16) Temple, Tracey J.; Goodwin, Catherine; Ladyman, Melissa K.; Mai, Nathalie; Coulon, Frederic
An Accelerated Solvent Extraction (ASE) method was developed and optimised to extract hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX) from a polyurethane matrix. The ASE method development was benchmarked against Soxhlet extraction with a view to improving extraction efficiency in terms of time and solvent volume. Key parameters for the ASE method development involved selecting the most appropriate solvent, optimising static time, ensuring a safe oven temperature for explosives, determination of a sufficient number of rinse cycles and effective sample preparation. To achieve optimal extraction, cutting the PBX samples to maximise solvent exposure was essential. The use of acetone with a static time of 10 minutes at 100 °C with three rinse cycles achieved 97 %±10 % extraction of RDX from PBX in 40 minutes using 72 mL solvent. Extraction time was reduced from 48 hours and solvent use by half compared to the standard Soxhlet extraction. To validate the developed ASE method, two other PBX samples containing different quantities of explosive were also fully extracted using the same parameters. Overall, ASE efficiency was comparable to Soxhlet, which places the ASE as a good alternative and shows potential for implementation as a standard method for other polymer based explosives.
Open Access
Primary alkyl phosphine-borane polymers: Synthesis, low glass transition temperature, and a predictive capability thereof
(American Chemical Society, 2017-11-30) Cavaye, H.; Clegg, F.; Gould, P. J.; Ladyman, Melissa K.; Temple, Tracey J.; Dossi, E.
With a multitude of potential applications, poly(phosphine-borane)s are an interesting class of polymer comprising main-group elements within the inorganic polymer backbone. A new family of primary alkyl phosphine-borane polymers was synthesised by a solvent-free rhodium catalysed dehydrocoupling reaction and characterised by conventional chemico-physical techniques. The thermal stability of the polymers is strongly affected by the size and shape of the alkyl side chain with longer substituents imparting greater stability. The polymers show substantial stability towards UV illumination and immersion in water however they undergo a loss of alkyl phosphine units during thermal degradation. The polymers exhibit glass transition temperatures (Tg) as low as -70 °C. A group interaction model (GIM) framework was developed to allow the semi-quantitative prediction of Tg values and the properties of the materials in this study were used to validate the model.
Open Access
Quantitative environmental assessment of explosive residues from the detonation of Insensitive High Explosive filled 155 mm artillery shell
(Wiley, 2022-01-11) Persico, Federica; Temple, Tracey J.; Ladyman, Melissa K.; Gilroy-Hirst, William; Guiterrez-Carazo, Encina; Coulon, Frederic
Insensitive High-Explosive (IHE) typically comprises up to five constituents including 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), which are mixed in various ratios to achieve desired performance and increase insensitivity. Insensitive munitions, which are designed to detonate on command and not accidentally, are currently in use in military operations and training areas around the world. However, there is minimal literature available on the physiochemical behavior of these materials in the environment, therefore the actual consequence of residues being deposited post-detonation is still an unexplored area of research. Three 155 mm artillery shells filled with an IHE mixture of 53 % NTO, 32 % DNAN, and 15 % RDX were detonated in an inert sand arena to collect and quantify residues. Post detonation, approximately 0.02 % NTO, and 0.07 % DNAN were deposited in the environment which may rapidly accumulate dependent on the number of rounds fired. This is of concern due to the toxicity of DNAN and its degradation products, and the potential for increased acidity of soil and discoloration of watercourses from NTO contamination.
Open Access
Release of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) from polymer-bonded explosives (PBXN 109) into water by artificial weathering
(Elsevier, 2016-11-28) Kumar, M.; Ladyman, Melissa K.; Mai, N.; Temple, Tracey J.; Coulon, Frederic
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.
Open Access
A review of treatment methods for insensitive high explosive contaminated wastewater
(Elsevier, 2021-07-01) Fawcett-Hirst, William; Temple, Tracey J.; Ladyman, Melissa K.; Coulon, Frederic
Insensitive high explosive materials (IHE) such as 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) are increasingly being used in formulations of insensitive munitions alongside 1,3,5-trinitroperhydro1,3,5-triazine (RDX). Load, assembly and packing (LAP) facilities that process munitions produce wastewater contaminated with IHE which must be treated before discharge. Some facilities can produce as much as 90,000 L of contaminated wastewater per day. In this review, methods of wastewater treatment are assessed in terms of their strengths, weaknesses, opportunities and threats for their use in production of IHE munitions including their limitations and how they could be applied to industrial scale LAP facilities. Adsorption is identified as a suitable treatment method, however the high solubility of NTO, up to 16.6 g.L which is 180 times higher that of TNT, has the potential to exceed the adsorptive capacity of carbon adsorption systems. The key properties of the adsorptive materials along the selection of adsorption models are highlighted and recommendations on how the limitations of carbon adsorption systems for IHE wastewater can be overcome are offered, including the modification of carbons to increase adsorptive capacity or reduce costs.
Open Access
The UK Ministry of Defence Project Orientated Environmental Management System (POEMS)
(Wiley, 2016-10) Ladyman, Melissa K.; Temple, Tracey J.; Gill, Philip P.; Galante, E.
The Project Orientated Environmental Management System (POEMS) is the UK Ministry of Defence (MoD) bespoke environmental management system for the acquisition and use of equipment. The full implementation of a site-specific environmental management system is challenging for the MoD because there are many permanent MoD sites with transient populations, frequently changing site activities and diverse types of equipment. Nevertheless, MoD policy requires that all sites are covered by an environmental management system. POEMS is based on international standards ISO14001 and ISO14040, which focus on environmental management systems and life cycle assessment, respectively. The primary aim of POEMS is to identify and manage any environmental aspects (causes) and impacts (effects) by scrutinising MoD equipment and activities during acquisition, operation and disposal. This is achieved by drawing up a priority list of activities associated with the equipment based on anticipated environmental impact scores, resulting in an environmental management plan that spans the life cycle of the equipment and any corresponding activities. This article describes the POEMS procedure for both experts and non-experts, and demonstrates the implementation of POEMS using a 105-mm artillery round as a theoretical case study. The results anticipated at each stage of the POEMS procedure are discussed in detail, and the documentation necessary to verify the correct application of POEMS is demonstrated.
Open Access
The use of a predictive threat analysis to propose revisions to existing risk assessments for precursor chemicals used in the manufacture of home-made explosives (HME)
(Elsevier, 2021-11-11) Collett, Gareth; Ladyman, Melissa K.; Hazael, Rachael; Temple, Tracey J.
Improvised explosive devices (IEDs) have generated over 137,000 civilian casualties in the past decade, more than any other explosive weapon system in the same period with a far-reaching impact on personal security freedoms across 50 affected countries. The aim of this paper is to consolidate existing risk management processes to control the availability of chemical precursors used in the manufacture of home-made explosives (HME) and to recommend global standards for market regulations in their composition, sale and use. This will be achieved by assessing the current regional regulations for three common chemical precursors (hydrogen peroxide, ammonium nitrate and potassium chlorate), and proposing a risk management process to identify key precursor chemicals that require greater control.

Browsing by Author "Ladyman, Melissa K."

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