Staff publications (CDS)

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Open Access
The M2/E2 30-06 round
(The European Cartridge Research Association (E.C.R.A.), 2024-09-01) Beedham, Richard
Open Access
Why the Afghan and Iraqi armies collapsed: an allied perspective
(United States Army War College Press, 2024-08-29) Robinson, Colin D.
Rather than military factors, American and Western liberal ideas (ideological views) and politics explain many of the obstacles faced in rebuilding the Afghan and Iraqi Armies. Liberal ideas largely determined what options the coalition would use. Ideological factors help explain democratization and reconstruction challenges, partner leaders with divergent aims, military-cultural factors and the Western combat focus, politicization, corruption, and nepotism. This article reviews the differences between Western liberal democracies and partner states, the politics of counterinsurgency, and army accounts. This article will assist US practitioners in security cooperation, institutional capacity building, and security assistance.
Open Access
Rapid climate change, integrated human–environment–historical records and societal resilience in Georgia
(MDPI AG, 2024-08-19) Loveluck, Christopher P; Tielidze, Levan G; Elashvili, Mikheil; Kurbatov, Andrei V; Gadrani, Lela; Erb-Satullo, Nathaniel; von Suchodoletz, Hans; Dan, Anca; Laermanns, Hannes; Brückner, Helmut; Schlotzhauer, Udo; Sulava, Nino; Chagelishvili, Rusudan
In the midlatitudes of the planet, we are facing the imminent disappearance of one of our best high-resolution (pre)historic climate and anthropogenic pollution archives, namely the loss of glacial ice, through accelerated global warming. To capture these records and interpret these vanishing archives, it is imperative that we extract ice-cores from midlatitude regions where glaciers still survive and analyse them within frameworks of inter-disciplinary research. In this paper, we focus on Georgia, part of the Greater Caucasus. Results of ice-core analyses from the region have never, to date, been integrated with its other abundant palaeo-environmental, archaeological and historical sources. We review the results of international projects on palaeo-environmental/geoarchaeological sediment archives, the archaeology of metal economies and preliminary ice-core data in Georgia. Collectively, we show that the different strands need to be integrated to fully explore relationships between climate/landscape change and human societal transformations. We then introduce an inclusive interdisciplinary framework for ongoing research on these themes, with an ultimate future goal of using data from the past to inform societal resilience strategies in the present.
Open Access
A two-stage classification method for improved positioning using low-cost inertial sensors
(IEEE, 2024-08-08) Maton, Dariusz; Economou, John; Galvao Wall, David; Khan, Irfan; Cooper, Robert; Ward, David; Trythall, Simon
The two-stage subtractive clustering Takagi-Sugeno (2SC-TS) method is proposed which completely replaces the established method of inertial navigation with classification models. The classifiers are designed by the subtractive clustering algorithm, an unsupervised learning method. The accuracy of the trajectories is compared against three competitive data-driven methods on three independent experimental datasets. The results show how 2SC-TS generates trajectories with approximately 20% lower positional error compared with the single-stage version (SC-TS), and halves the error produced by competitive deep learning methods. The proposed method may help improve the positioning of people and robots carrying low-cost inertial sensors.
Open Access
Design of super wide band 3‐way power divider/combiner
(Institution of Engineering and Technology (IET), 2024-08-21) Mungara, Nagarakshith; Ray, Kamla Prasan
A 1:3‐way power divider/combiner has been proposed for much improved bandwidth and isolation between output ports. The matching network for the super wide bandwidth frequency range is designed using a combination of the Klopfenstein taper and the triangular taper. The proposed design yields bandwidth from 1.5 to 20 GHz (18.5 GHz) for return loss better than 15 dB and isolation better than 20 dB. The insertion loss for the entire frequency band is 0.8 dB which is only 0.34 dB for the ultra‐wide bandwidth (3.1–10.6 GHz). The maximum phase imbalance of 3.32° and amplitude imbalance of 0.199 dB between all the output ports have been achieved over the entire bandwidth. The simulated results have been validated experimentally.
Open Access
Genetic dissection of minerals and phytate content in pearl millet germplasm panel using genome‐wide association study
(Wiley, 2024-07) Singh, Satbeer; Manwaring, Hanna Rose; Naveen, Aavula; Hegarty, Matthew; Yadav, Rattan S
Billions of people around the world suffer from malnutrition, leading to severe adverse health effects. Pearl millet (Pennisetum glaucum) is a multifaceted versatile crop with excellent nutritional profile which can help to combat nutritional disorders and climate change. In this study, we evaluated the global pearl millet germplasm panel known as PMiGAP for natural variation and genetic maker trait associations for important minerals, that is, iron, zinc, calcium, magnesium, potassium and sodium along with phytate. The genotypes IP‐15947, IP‐5121, IP‐4020, IP‐12768, IP‐5695, IP‐8786 and IP‐11310 were found to be superior for majority of minerals examined but had lower phytate‐to‐zinc ratio. Phytate/mineral molar ratios are typically used to predict the bioavailability of iron and calcium contents in grains, and surprisingly none of the PMiGAP genotypes showed such ratios below threshold indicating PMiGAP entries studied in this study seriously suffer from bioavailability issues of these minerals. On the other hand, 73 genotypes had lower zinc/phytate ratio than the threshold in the germplasm panel. Iron and zinc content had significant positive association among them but phytate content in general was not significantly correlated with minerals except for magnesium and potassium. A genome‐wide association study using 456 K SNPs identified 74 significant marker–trait associations and 59 candidate genes around 50 Kb distance near the significant SNPs. Ten significant SNPs were found within the candidate genes. The associated markers and the candidate genes provide new insights into the genetic architecture of the mineral traits studied and will facilitate marker‐assisted selection to accelerate breeding of such minerals in future varieties to combat rising malnutrition problem via diet.
Open Access
Modular ballistic pendulum for measurement of impulse from tamped explosives
(OneMine.Org, 2023-02-06) Alford, Roland; Hazael, Rachael; Critchley, Richard
The ballistic pendulum is a well-established piece of test equipment originally developed for estimating the velocity of bullets and projectiles. When trying to understand the effects of different tamping methods on explosive performance, the ballistic pendulum is an excellent tool allowing calculation of explosive charge impulse. Most ballistic pendula for this application are limited to narrow impulse ranges as the pendulum mass determines the angle of swing; and a mass capable of being moved by a small charge would be far too small for a larger charge. This paper describes a modular design (the Alford Modular Ballistic Pendulum) which overcomes this problem.
Open Access
Advances in the characterisation and identification of mastic (Pistacia sp.) resin in archaeological samples by GC-QToF-MS
(Royal Society of Chemistry (RSC), 2024-01-02) Tamburini, Diego; Fulcher, Kate; Briggs, Lisa; von Aderkas, Nelly; Pulak, Cemal; Stacey, Rebecca
The optimisation and application of an analytical method based on gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QToF-MS) is proposed for the first time for the characterisation and identification of mastic (Pistacia sp.) resin in archaeological samples. The GC-QToF-MS method demonstrated higher sensitivity compared to single quadrupole GC-MS and enabled enhanced structural elucidation power to be exploited, particularly due to the high mass resolution and accuracy, the possibility to use standard and low ionisation energies as well as its tandem MS capabilities. The heat-induced degradation of the resin was also studied in open air conditions, showing that 28-norolean-17-en-3-one forms upon heating, but then progressively degrades. This makes it a reliable marker for heating of Pistacia resin; however, the lack of detection does not imply that the resin was not heated. These observations were used to interpret the results of a large number of archaeological samples containing Pistacia resin in different formulations, from various archaeological contexts and exposed to different environmental conditions. Lumps of relatively pure resin found in marine waterlogged conditions (Uluburun shipwreck, Turkey), residues on ceramics from Sai Island (Nubia, Sudan) as well as varnish and coating layers on Egyptian coffins from the collections of the British Museum (London, UK) and Fitzwilliam Museum (Cambridge, UK) were analysed to understand what the molecular profiles reveal about the use of the resin. The results showed that the resin was often mixed with a drying or semi-drying oil in ancient varnish formulations, thus suggesting that oil was used as a medium to dissolve the resin, which would have been impossible to apply as a layer using simple heat. These new observations significantly add to our understanding of ancient Egyptian technology and provide museum scientists and conservators with key information to accurately identify Pistacia resin and preserve objects containing it.
Open Access
Understanding and comparing digital traces
(Taylor and Francis, 2024-07-25) Horsman, Graeme
Digital forensic practitioners will encounter digital traces during their examinations which they must take steps to understand. This may involve trying to attribute an ‘activity’ to a trace (what created it) or determine where it came from (its ‘source’) – Trace-to-Activity/Source interpretation. Alternatively, they may need to determine if an activity has taken place on a system by identifying traces denoting it – Activity-to-Trace interpretation. In both instances, practitioners may need to conduct tests and/or identify research which will help them understand a trace, and compare any results of their testing/research to the traces in their casework. This work describes both the Trace-to-Activity/Source and Activity-to-Trace interpretive journeys, as well as the steps contained in both. In addition, six ‘trace comparison criteria’ are proposed and discussed to help those carrying out a trace comparison, notably: ‘trace location’, ‘trace structure’, ‘trace examination method’, ‘trace metadata’, ‘trace content’, and ‘trace context’.
Open Access
Vitacrystallography: structural biomarkers of breast cancer obtained by X-ray scattering
(MDPI, 2024-07-09) Denisov, Sergey; Blinchevsky, Benjamin; Friedman, Jonathan; Gerbelli, Barbara; Ajeer, Ash; Adams, Lois; Greenwood, Charlene; Rogers, Keith; Mourokh, Lev; Lazarev, Pavel
Simple Summary Breast cancer ranks as the most prevalent cancer among women. Current screening includes regular mammography and subsequent biopsy if the mammography results are abnormal. These procedures are costly and uncomfortable. We propose an alternative non-invasive method based on X-ray scattering. Using a machine learning approach, we have examined almost 3000 measurements of cancerous and non-cancerous samples belonging to 110 patients and shown excellent results on cancer/non-cancer separation. This can lead to patient-friendly, fast, and economical solutions for breast cancer screening to complement mammography and reduce biopsy. It should be emphasized that this approach can be readily extended to other types of cancer and even other diseases. Abstract With breast cancer being one of the most widespread causes of death for women, there is an unmet need for its early detection. For this purpose, we propose a non-invasive approach based on X-ray scattering. We measured samples from 107 unique patients provided by the Breast Cancer Now Tissue Biobank, with the total dataset containing 2958 entries. Two different sample-to-detector distances, 2 and 16 cm, were used to access various structural biomarkers at distinct ranges of momentum transfer values. The biomarkers related to lipid metabolism are consistent with those of previous studies. Machine learning analysis based on the Random Forest Classifier demonstrates excellent performance metrics for cancer/non-cancer binary decisions. The best sensitivity and specificity values are 80% and 92%, respectively, for the sample-to-detector distance of 2 cm and 86% and 83% for the sample-to-detector distance of 16 cm.
Open Access
Design of a stacked circularly polarized slot-patch antenna for X-band applications
(IEEE, 2024-07-19) Pascarella, Francesca; Mugnaini, Sara; Balleri, Alessio; Scarselli, Chiara; Brizi, Danilo; Monorchio, Agostino
This paper introduces a numerically investigation of a compact stacked Circularly Polarized (CP) slot-patch antenna designed to operate in X-band (8 -12 GHz). The proposed solution features a coaxially fed circular radiating patch etched on a dielectric substrate, which includes two sector notches positioned on opposite sides at a 45° inclination to achieve circular polarization. Two additional dielectric substrates are placed on the top of the radiating patch, with a parasitic passive patch positioned on each, with the aim of enlarging the overall operating bandwidth. The numerical results demonstrated that the configuration is able to cover a 2.2 GHz band, achieving a minimal Axial Ratio (AR) of 1.2 dB and a gain of 7.4 dB at 10 GHz.
Open Access
Understanding the explosion risk presented by ammonium nitrate and aluminium home-made explosives detonated as surface charges in hexahedral main charge containers
(Springer, 2024-07-15) Collett, Gareth; Akhavan, Jacqueline; Critchley, Richard
Ammonium nitrate and aluminium (AN–Al) has been used as a typical homemade explosive (HME) by non-state actors since the turn of the century. Despite the regulation applied to ammonium nitrate above 16% nitrogen content and an aluminium particle size below 200 µm, their use has been widespread in Afghanistan, Columbia, Iraq, Syria and Yemen. Containers used to utilise AN–Al as a man-portable improvised explosive device (IED) are typically hexahedral in shape, not the spherical or hemispherical geometries used to theorise risk mitigation. This is particularly important in post-blast investigation where explosives of a non-ideal nature are often used in non-spherical containers. Given the breadth of HME available to criminals, the explosion performance of forty hexahedral containers filled with AN–Al of unknown manufacture is examined. Performance of the AN–Al is determined through the surface detonation of these containers on alluvial soil, with apparent crater volume compared to theoretical calculations for spherical charges of TNT detonated in that same medium. A conversion factor for hexahedral main charges to spherical charges is then established to achieve more accurate predictions of the explosion risk using Kingery-Bulmash and Bowen curves. The paper provides worked examples for practical application and a methodology by which predictions of charge mass in other mediums such as asphalt can be determined.
Open Access
An experimental method of determining explosive equivalency when scaled distance approaches zero
(International Society of Explosives Engineers, 2024-01-01) Alford, Roland; Hazael, Rachael; Critchley, Richard
The ability to compare explosives is fundamental. Numerous methods are used and while simple conversion factors are often used, the use of TNT Equivalency (TNTe) is not a simple subject as explosives exhibit very different equivalencies depending on whether the pressure or impulse are being considered as well as other conditions. The scaled distance has been found to have a significant effect on the TNTe but due to the difficulty of taking measurements at very close ranges, no TNTe have been quoted for charges in direct contact (Z=0). This paper describes the use of a ballistic pendulum to measure the impulse from contact charges and presents some surprising results that require a two-stage propulsion, as originally described by Backofen, to be explained.
Open Access
The Lake Paravani archive – a contribution to the late Quaternary landscape evolution of the Lesser Caucasus (Georgia)
(Wiley, 2024-07-01) Gademann, Daniel; Ustiashvili, Nino; Adikashvili, Luka; Navrozashvili, Levan; Erb-Satullo, Nathaniel L.; van der Meij, W. Marijn; Kirkitadze, Giorgi; Koff, Tiiu; Elashvili, Mikheil; Brückner, Helmut; Laermanns, Hannes
Lake Paravani, located on the volcanic Javakheti Plateau in the central part of the Lesser Caucasus at 2073 m a.s.l., forms a unique geo-bio-archive for palaeoenvironmental reconstructions in this remote region. Based on sediment cores from the southwestern part of the lake we expand the existing palynological and sedimentological records beyond the Last Glacial Maximum (LGM). For the first time, it is possible to reconstruct the palaeoenvironment in this part of the Lesser Caucasus back to c. 28 cal. ka BP. Our study shows that until 16 cal. ka BP glacial conditions dominated (Phase I) in the region; there is, however, proof that the lake already existed during the LGM. In the following transitional Phase II from 16 until 6 cal. ka BP, cold and arid conditions with sparse steppe vegetation and a lowered lake level prevailed. Around 10 cal. ka BP, tree pollen started to expand while herbaceous pollen, especially Chenopodiaceae, declined. In Phase III, since 6 cal. ka BP, mixed forest probably represented the Holocene climatic optimum. Fluctuating lake levels indicate shifting climatic conditions. The minor changes of arboreal pollen hin the uppermost part of Phase II may be an indication of human activity. The more humid, vegetation-rich environment and mild climate around 4.5–2 cal. ka BP correlate with the expansion of the Late Bronze Age settlements in this area (from ~3.5 cal. ka BP/~1.5 ka BC). The proliferation of sites on the plateau, along with even higher-altitude sites possibly dating to the same period, may indicate that this climate amelioration played an important role in enabling more sustained human occupation. The results extend the record on Lake Paravani by several millennia beyond the LGM and complement the palaeo-lake reconstructions of the wider region, e.g. at Lake Van (Türkiye) or Lake Sevan (Armenia).
Open Access
CCS0025: Written evidence for the Environmental Audit Committee of the UK Parliament in relation to climate change and security
(UK Parliament. House of Commons Select Committee. Environmental Audit Committee, 2024-05-15) Wilkinson, Edith; Morrell, Kevin
Open Access
Resolving full-wave through-wall transmission effects in multi-static synthetic aperture radar
(IOP Publishing, 2024-07-09) Watson, Francis; Andre, Daniel; Lionheart, W. R. B.
Through-wall synthetic aperture radar (SAR) imaging is of significant interest for security purposes, in particular when using multi-static SAR systems consisting of multiple distributed radar transmitters and receivers to improve resolution and the ability to recognise objects. Yet there is a significant challenge in forming focused, useful images due to multiple scattering effects through walls, whereas standard SAR imaging has an inherent single scattering assumption. This may be exacerbated with multi-static collections, since different scattering events will be observed from each angle and the data may not coherently combine well in a naive manner. To overcome this, we propose an image formation method which resolves full-wave effects through an approximately known wall or other arbitrary obstacle, which itself has some unknown 'nuisance' parameters that are determined as part of the reconstruction to provide well focused images. The method is more flexible and realistic than existing methods which treat a single wall as a flat layered medium, whilst being significantly computationally cheaper than full-wave methods, strongly motivated by practical considerations for through-wall SAR.
Embargo
Characterisation and fragmentation of brass and copper pipe bombs when using different initiation locations
(DEStech Publications, 2023-12-31) Plagge, Nina; Harris, Mike; Painter, Jonathan
The fragmentation characteristics of pipe bombs made from copper and brass, filled with a single base propellant, and initiated with an electric match positioned either at the end or halfway along the pipe were studied. A rig was devised to negate any variation from the effectiveness of end caps. Fragments were captured in strawboard packs and recovered to enable imaging and Fragment Weight Distribution Mapping (FWDM) graphs. The position of the initiator had a measurable effect on the fragmentation of the copper pipe, with the middle-initiated pipes having a higher relative power. In contrast, no such clear link was evident for the brass pipes. This likely indicates that the initiator location has less of an effect in stronger materials which are able to confine the propellant prior to rupturing.
Open Access
Modified Arrhenius kinetics for double base propellant decomposition: effect of water
(Elsevier, 2024-05-31) Romero Jabalquinto, Alonso; Mai, Nathalie; Belghiche, Samira; Gill, Philip P.
Numerous studies have been conducted on the decomposition mechanisms of cellulose nitrate (NC), a polymer employed in double base (DB) rocket propellants. It is well known that storage temperature affects the lifetime of these energetic formulations. However, less studies have been published on the influence of water. This research examined the role of water on the stabiliser consumption rate during accelerated ageing of a DB rocket propellant, as well as the impact on the shelf life prediction of the energetic formulation. Different volumes of water (0.8, 1.6, 2 and 4 µl/g) were added to the propellant in sealed vials, which were then isothermally aged (70, 80, 90, 100 °C). Analyses of the stabiliser consumption showed a faster decomposition kinetics in presence of water which is indirectly linked to the shortening of the storage life of the NC based propellant by 35 %. For the conditions, an activation energy of 133 ± 4 kJ/mol was reported for the water catalytic decomposition mechanism. A numerical model that included water as a variable was reported to reduce the uncertainty in the determination of the service life of NC based propellant. International standards such as Allied Ordnance Publication 48 should not overlook the effect of water/moisture on the safety of ammunition containing NC and should implement a modified Arrhenius equation.
Open Access
Guest editorial: Climate Neutral Supply Chains
(IEEE, 2024-04-30) Mukandwal, Prabhjot; Guntuka, Laharish; Aktas, Emel
Open Access
Combined intensity and coherent change detection with four classes for laboratory multistatic polarimetric synthetic aperture radar
(Institution of Engineering and Technology (IET), 2024-06-14) Hagelberg, Alexander; Andre, Daniel; Finnis, Mark
Satellites and drone swarms can be used to collect multistatic Synthetic Aperture Radar (SAR) images. Synthetic Aperture Radar images can be used for Intelligence Surveillance and Reconnaissance. One method is to use Coherent Change Detection (CCD) to identify changes such as objects or tracks in the scene. This paper investigates a two-stage change detector, formed using intensity change and CCD images, extended to laboratory measured multistatic SAR data. A variety of performance metrics are used to quantitatively assess the results. Bistatic results are compared to a variety of multistatic and fully polarimetric results. The improvement in performance of multistatic and fully polarimetric images over bistatic images is shown. Additionally challenges and limitations of using multistatic datasets are highlighted.