Now showing items 577-596 of 626

• #### Torsion units in the integral group ring of PSL(3,4)

We investigate the Zassenhaus Conjecture for the integral group ring of the simple group PSL(3,4).
• #### Total war and its effects on the live music industry in Cheshire and North Wales

Given the profound effect which World War II had on the economy of the UK as a whole, it would be surprising if specific areas of that economy – such as live music in the provinces – were not affected as well. How did ‘total war’ affect the live music industry on a local level? Evidence I have collected for a study of musicians active in and around Chester during the period suggests that the large number of military bases in the area, combined with the effects of other wartime factors such as conscription, rationing and the need to maintain both military and civilian morale, did indeed affect the size and nature of the market for live dance music locally. For instance, the large US Air Force base at Burtonwood was a source of work for local musicians, as well as an opportunity to mix with American musicians and music fans. As well as presenting information obtained through interviews with musicians and their relatives, I will also look briefly at what happened to the musicians and the bands after the war, when economic and social conditions changed again, at the same time as advances occurred in music-related technology.
• #### Towards Cyber-User Awareness: Design and Evaluation

Human reliance on interconnected devices has given rise to a massive increase in cyber activities. There are about 17 billion interconnected devices in our World of about 8 billion people. Like the physical world, the cyber world is not void of entities whose activities, malicious or not, could be detrimental to other users who remain vulnerable as a result of their existence within cyberspace. Developments such as the introduction of 5G networks which advances communication speed among interconnected devices, undoubtedly proffer solutions for human living as well as adversely impacting systems. Vulnerabilities in applications embedded in devices, hardware deficiencies, user errors, are some of the loopholes that are exploited. Studies have revealed humans as weakest links in the cyber-chain, submitting that consistent implementation of cyber awareness programs would largely impact cybersecurity. Cyber-active systems have goals that compete with the implementation of cyber awareness programs, within limited resources. It is desirable to have cyber awareness systems that can be tailored around specific needs and considerations for important factors. This paper presents a system that aims to promote user awareness through a flexible, accessible, and cost-effective design. The system implements steps in a user awareness cycle, that considers human-factor (HF) and HF related root causes of cyber-attacks. We introduce a new user testing tool, adaptable for administering cybersecurity test questions for varying levels and categories of users. The tool was implemented experimentally by engaging cyber users within UK. Schemes and online documentations by UK Cybersecurity organisations were harnessed for assessing and providing relevant recommendations to participants. Results provided us with values representing each participants’ notional level of awareness which were subjected to a paired-T test for comparison with values derived in an automated assessment. This pilot study provides valuable details for projecting the efficacy of the system towards improving human influence in cybersecurity.
• #### Towards Organisational Learning Enhancement: Assessing Software Engineering Practice

• Purpose – Issues surrounding knowledge management, knowledge transfer and learning within organisations challenge continuity and resilience in the face of changing environments. While initiatives are principally applied within large organisations, there is scope to assess how the processes are handled within small and medium enterprises (SMEs) and to consider how they might be enhanced. This paper presents an evaluation of practice within an evolving software development unit to determine what has been learned and how the knowledge acquired has been utilised to further organisational development. These results provide the basis for the design and implementation of a proposed support tool to enhance professional practice. • Design/methodology/approach – A small software development unit, which has successfully delivered bespoke systems since its establishment a number of years ago, was selected for analysis. The unit operates as a team whose actions and behaviours were identified and validated by the following means: in-depth interviews were carried out with each member of the team to elicit an understanding of individual and collective development. Interview data were recorded and transcribed and subjected to qualitative analysis to identify key themes underpinning knowledge acquisition and utilisation. Samples of project documentation were scrutinised to corroborate interview data. After analysing the data, a focus-group meeting was held to validate the results and to generate further insights into learning within the team. • Findings - Qualitative analysis of the data revealed key changes in thinking and practice within the team as well as insight into the development of individual and collective contextual knowledge, tacit understanding and learning. This analysis informed the proposal of a bespoke, lightweight, web-based system to support knowledge capture and organisational learning (OL). This approach has the potential to promote resilience and to enhance practice in similar small or start-up enterprises. • Research limitations/implications – Purposeful sampling was used in selecting a small software development team. This enabled in-depth interviewing of all members of the team. This offered a rich environment from which to derive awareness and understanding of individual and collective knowledge acquisition and learning. Focusing on a single small enterprise limits the extent to which the findings can be generalised. However, the research provides evidence of effective practice and learning and has identified themes for the development of a support tool. This approach can be extended to similar domains to advance research into learning and development. • Practical implications – Results of the work undertaken so far have generated promising foundations for the proposed support tool. This offers software developers a system within which they can reflect upon, and record, key learning events affecting technical, managerial and professional practice. • Originality/value – Small enterprises have limited resources to support OL. The qualitative research undertaken so far has yielded valuable insight into the successful development of a single software development team. The construction of a support tool to enhance knowledge acquisition and learning has the capacity to consolidate valuable, and potentially scarce, expertise. It also has the potential to facilitate further research to determine how the prototype might be extended or revised to improve its contribution to the team’s development.
• #### Towards sustainable methanol from industrial CO2 sources

This chapter discusses the opportunity of using CO2 from industrial sources to produce sustainable methanol. Some important industrial sectors that could be seen as potential sources of CO2 are reviewed: ammonia, steel, ethanol, ethylene, natural gas, cement and power industries. In most cases, despite a promising potential for CO2 re-use, only few projects have been identified and methanol production from CO2 is still marginal. A model for the CO2-to-methanol process is presented based on CO2-rich gas coming from ammonia production process. This model takes into account the different steps from the CO2 capture to the methanol purification, and heat integration is performed in order to determine the reduction of heat consumption achievable for the global process. Even if the economic relevance of the CO2 re-use into methanol still has to be qualified, it offers an estimation of the process efficiency.
• #### Training Powered Wheelchair Manoeuvres in Mixed Reality

We describe a mixed reality environment that has been designed as an aid for training driving skills for a powered wheelchair. Our motivation is to provide an improvement on a previous virtual reality wheelchair driving simulator, with a particular aim to remove any cybersickness effects. The results of a validation test are presented that involved 35 able bodied volunteers divided into three groups: mixed reality trained, virtual reality trained, and a control group. No significant differences in improvement was found between the groups but there is a notable trend that both the mixed reality and virtual reality groups improved more than the control group. Whereas the virtual reality group experienced discomfort (as measured using a simulator sickness questionnaire), the mixed reality group experienced no side effects.
• #### Translational Medicine: Challenges and new orthopaedic vision (Mediouni-Model)

Background: In North America and three European countries Translational Medicine (TM) funding has taken center stage as the National Institutes of Health (NIH), for example, has come to recognize that delays are common place in completing clinical trials based upon benchside advancements. Recently, there are several illustrative examples whereby the translation of research had untoward outcomes requiring immediate action. Methods: Focus more on three-dimensional (3D) simulation, biomarkers, and Artificial Intelligence may allow orthopaedic surgeons to predict the ideal practices before orthopaedic surgery. Using the best medical imaging techniques may improve the accuracy and precision of tumor resections. Results: This article is directed at the young surgeon scientist and in particular orthopaedic residents and all other junior physicians in training to help them better understand TM and position themselves in career paths and hospital systems that strive for optimal TM. It serves to hasten the movement of knowledge garnered from the benchside and move it quickly to the bedside. Conclusions: Communication is ongoing in a bidirectional format. It is anticipated that more and more medical Centers and institutions will adopt TM models of healthcare delivery.
• #### Traversing social networks in the virtual dance hall: visualizing history in VR

Digital recreations of historical sites and events are important tools both for academic researchers and for public interpretation. Current 3D visualization and VR technologies enable these recreations to be increasingly immersive and engaging. This poster describes a case study based on a mid-twentieth century Chester dance hall, examining the possibilities and limitations of 3D VR for recreating a public music venue which no longer physically exists, and also for visualizing and analyzing the professional network of musicians who played there, and at many other local venues.
• #### Treating wastewater by indigenous microalgae strain in pilot platform located inside a municipal wastewater treatment plant

Various resources from a municipal wastewater treatment plant (MWTP) are available for microalgae cultivation plants, suggesting that a combination of these technologies can be used to produce microalgae biomass and remove contaminants at a low cost. In this study, the growth performance and nutrient removal efficiency of an indigenous Scenedesmus sp. in various wastewater media with different exchange patterns were investigated firstly, then transferred to a pilot-scale photobioreactor (located inside a MWTP) for bioremediation use. The temperature and pH of the platform were maintained at 15–30°C and 7.6, respectively. The NH+4− N, NO−3− N, and PO3−4− P of the wastewater could be reduced to below 0.05, 0.40, and 0.175 mg L–1, respectively. Our results indicate that microalgae cultivation using the resources of a MWTP can achieve high algal biomass productivity and nutrient removal rate. Our study also suggests that efficient technology for controlling zooplankton needs to be developed.
• #### Trion formation in a two-dimensional hole-doped electron gas

The interaction between a single hole and a two-dimensional, paramagnetic, homogeneous electron gas is studied using diffusion quantum Monte Carlo simulations. Electron-hole relaxation energies, pair-correlation functions, and electron-hole center-of-mass momentum densities are reported for a range of electron-hole mass ratios and electron densities. We find numerical evidence of a crossover from a collective excitonic state to a trion-dominated state in a density range in agreement with that found in recent experiments on quantum-well heterostructures.
• #### Twenty-Eight Orders of Parametric Resonance in a Microelectromechanical Device for Multi-band Vibration Energy Harvesting

This paper contends to be the first to report the experimental observation of up to 28 orders of parametric resonance, which has thus far only been envisioned in the theoretical realm. While theory has long predicted the onset of n orders of parametric resonance, previously reported experimental observations have been limited up to about the first 5 orders. This is due to the rapid narrowing nature of the frequency bandwidth of the higher instability intervals, making practical accessibility increasingly more difficult. Here, the authors have experimentally confirmed up to 28 orders of parametric resonance in a micromachined membrane resonator when electrically undamped. While the implication of this finding spans across the vibration dynamics and transducer application spectrum, the particular significance of this work is to broaden the accumulative operational frequency bandwidth of vibration energy harvesting for enabling self-powered microsystems. Up to 5 orders were recorded when driven at 1.0g of acceleration across a matched load of 70kΩ. With a natural frequency of 980Hz, the fundamental mode direct resonance had a −3dB bandwidth of 55Hz, in contrast to the 314Hz for the first order parametric resonance; furthermore, the half power bands of all 5 orders accumulated to 478Hz.
• #### Two high-order time discretization schemes for subdiffusion problems with nonsmooth data

Two new high-order time discretization schemes for solving subdiffusion problems with nonsmooth data are developed based on the corrections of the existing time discretization schemes in literature. Without the corrections, the schemes have only a first order of accuracy for both smooth and nonsmooth data. After correcting some starting steps and some weights of the schemes, the optimal convergence orders $O(k^{3- \alpha})$ and $O(k^{4- \alpha})$ with $0< \alpha <1$ can be restored for any fixed time $t$ for both smooth and nonsmooth data, respectively. The error estimates for these two new high-order schemes are proved by using Laplace transform method for both homogeneous and inhomogeneous problem. Numerical examples are given to show that the numerical results are consistent with the theoretical results.
• #### A two-channel, Thermal Dissociation Cavity-Ringdown Spectrometer for the detection of ambient NO2, RO2NO2 and RONO2

We describe a thermal dissociation cavity ring-down spectrometer (TD-CRDS) for measurement of ambient NO2, total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs). The spectrometer has two separate cavities operating at  ∼  405.2 and 408.5 nm. One cavity (reference) samples NO2 continuously from an inlet at ambient temperature, the other samples sequentially from an inlet at 473 K in which PNs are converted to NO2 or from an inlet at 723 K in which both PNs and ANs are converted to NO2, difference signals being used to derive mixing ratios of ΣPNs and ΣANs. We describe an extensive set of laboratory experiments and numerical simulations to characterise the fate of organic radicals in the hot inlets and cavity and derive correction factors to account for the bias resulting from the interaction of peroxy radicals with ambient NO and NO2. Finally, we present the first measurements and comparison with other instruments during a field campaign, outline the limitations of the present instrument and provide an outlook for future improvements.
• #### Ultrafast Electric Field-induced Phase Transition in Bulk Bi0.5Na0.5TiO3 under High Intensity Terahertz Irradiation

Ultrafast polarization switching is being considered for the next generation of ferroelectric based devices. Recently, the dynamics of the field-induced transitions associated with this switching have been difficult to explore, due to technological limitations. The advent of terahertz (THz) technology has now allowed for the study of these dynamic processes on the picosecond (ps) scale. In this paper, intense terahertz (THz) pulses were used as a high-frequency electric field to investigate ultrafast switching in the relaxor ferroelectric, Bi0.5Na0.5TiO3. Transient atomic-scale responses, which were evident as changes in reflectivity, were captured by THz probing. The high energy THz pulses induce an increase in reflectivity, associated with an ultrafast field-induced phase transition from a weakly polar phase (Cc) to a strongly polar phase (R3c) within 20 ps at 200 K. This phase transition was confirmed using X-ray powder diffraction and by electrical measurements which showed a decrease in the frequency dispersion of relative permittivity at low frequencies.
• #### Understanding the impact of cavitation on hydrocarbons in the middle distillate range

Hydrocarbons in the middle distillate range (C8 - C26) have been treated with ultrasound at 20 kHz - a frequency sufficient to drive acoustic cavitation. The high temperatures experienced as a result of the implosion of fuel vapour bubbles are sufficient to produce pyrolytic degradation and dehydrogenation, as well as a growth mechanism that results in the formation of small particles that have similarities with the primary soot particles produced during diesel combustion. These nanosized particles agglomerate as a result of kinetically driven collisions during cavitation to form a dispersion of micron sized particles in the treated hydrocarbon. The particles are carbonaceous in character, being a mixture of amorphous and graphitic-like carbon. The mass of material produced increases with the C/H atomic ratio of the hydrocarbon undergoing cavitation and is decreased through the addition (1 - 3 %v/v) of low boiling paraffinic hydrocarbons, possibly as a result of lowering the temperature developed inside imploding cavities. Dispersions of microparticles contain equilibrated levels of nanoparticles. If sufficiently high numbers of these smaller primary particles are present they agglomerate due to thermally driven collisions during post-cavitation storage. When this happened a sharp rise in the number of 1 - 2 µm particles was seen after only a few days. Some evidence is presented for the behaviour of ultrasonically treated hydrocarbons being related to the degradation of diesel fuel exposed to hydrodynamic cavitation in the fuel systems of modern common rail direct injection diesel engines.
• #### Understanding the relationship between ignition delay and burn duration in a constant volume vessel at diesel engine conditions

Experiments were performed in a constant volume vessel, with fuel sprays injected into the vessel at various different pressure and temperature conditions chosen to represent diesel engine operation at various loads. A range of diesel primary reference fuels (i.e. mixtures of cetane and heptamethylnonane) of varying cetane number (CN) were tested, and as expected lower CN fuels have longer ignition delays. Burn period was plotted against ignition delay and two distinct trends can be seen: “mainly diffusion” diesel combustion in which burn period decreases with ignition delay and “mainly pre-mixed” diesel combustion in which burn period increases with ignition delay. There is typically a minimum in plots of burn period versus ignition delay which represents the transition between the two types of combustion mode. Higher CN, higher engine load and higher boost pressure would seem to favour “mainly diffusion” combustion whilst lower CN, lower loads and non boosted conditions favour “mainly pre-mixed” combustion.
• #### Underwhelming the immune response: Effect of slow virus growth on CD8+-T-lymphocyte responses

The speed of virus replication has typically been seen as an advantage for a virus in overcoming the ability of the immune system to control its population growth. Under some circumstances, the converse may also be true: more slowly replicating viruses may evoke weaker cellular immune responses and therefore enhance their likelihood of persistence. Using the model of lymphocytic choriomeningitis virus (LCMV) infection in mice, we provide evidence that slowly replicating strains induce weaker cytotoxic-T-lymphocyte (CTL) responses than a more rapidly replicating strain. Conceptually, we show a "bell-shaped" relationship between the LCMV growth rate and the peak CTL response. Quantitative analysis of human hepatitis C virus infections suggests that a reduction in virus growth rate between patients during the incubation period is associated with a spectrum of disease outcomes, from fulminant hepatitis at the highest rate of viral replication through acute resolving to chronic persistence at the lowest rate. A mathematical model for virus-CTL population dynamics (analogous to predator [CTL]-prey [virus] interactions) is applied in the clinical data-driven analysis of acute hepatitis B virus infection. The speed of viral replication, through its stimulus of host CTL responses, represents an important factor influencing the pathogenesis and duration of virus persistence within the human host. Viruses with lower growth rates may persist in the host because they "sneak through" immune surveillance.
• #### The United Kingdom Ministry of Defence and the European Union's electrical and electronic equipment directives

The growth of the generation of Electrical and Electronic Equipment (EEE), and the use of hazardous substances in the production of these items, has required legislation to minimise the harm to the environment that their existing use, ultimate disposal and continued growth of the sector may pose. The European Union (EU) started to tackle this problem with the passing of two Directives in 2002, which focused on restricting the use of hazardous substances (RoHS - 2002/95/EC) and organising the recycling or disposal of discarded electronic and electrical equipment (WEEE - 2002/96/EC). These Directives have been recently recast and their scope widened; however, one exception to them remains items specifically designed for defence and military purposes. This paper looks at how and why these European Directives were passed, the impact they have had on defence in the United Kingdom (UK) up to the present moment, what impact the further extension of those directives might have on UK defence policy and how the UK Ministry of Defence (MOD) has begun to prepare for any extension, including the use of alternative products from the commercial market, and substituting less harmful materials. The paper reviews the information available to carry out future decision making and what level of decision making it can support. Where the data is insufficient, it makes recommendations on actions to take for improvement.
• #### Units of the group algebra of the group $C_n\times D_6$ over any finite field of characteristic $3$

In this paper, we establish the structure of the unit group of the group algebra ${\FF}_{3^t}(C_n\times D_6)$ for $n \geq 1$.
• #### The Use of Stereoscopy in a Neurosurgery Training Virtual Environment

We have previously investigated the effectiveness of a custom built virtual environment in assisting training of a ventriculostomy procedure, which is a commonly performed procedure by a neurosurgeon and a core task for trainee surgeons. The training tool (called VCath) was initially developed as a low fidelity app for a tablet platform to provide easy access and availability to trainees. Subsequently we have developed a high fidelity version of VCath that uses a stereoscopic display to immerse the trainee in the virtual environment. This paper reports on two studies that have been carried out to compare the low and high fidelity versions of VCath, particularly to assess the value of stereoscopy. Study 1 was conducted at the second annual boot camp organized for all year one trainees in neurosurgery in the UK. Study 2 was performed on lay people, with no surgical experience. Our hypothesis was that using stereoscopy in the training task would be beneficial. Results from Study 1 demonstrated that performance improved for both the control group and the group trained with the tablet version of VCath. The group trained on the high fidelity version of VCath with a stereoscopic display showed no performance improvement. The indication is that our hypothesis is false. In Study 2, six different conditions were investigated that covered the use of training with VCath on a tablet, a mono display at two different sizes, a stereo display at two different sizes, and a control group who received no training. Results from this study with lay people show that stereoscopy can make a significant improvement to the accuracy of needle placement. The possible reasons for these results and the apparent contradiction between the two studies are discussed.