The mechanical and wear behaviour of B(SiC) fibre-reinforced composite materials

The mechanical properties and wear behaviour of B(SiC) fibre-reinforced metal matrix composites (MMCs) and aluminium alloy (2014) produced by metal infiltration technique were determined. Tensile tests were peliormed at different conditions on both the alloy matrix and its composite, and the tensile fracture surfaces were also examined by Scanning Electron Microscopy (SEM). Dry wear of the composite materials sliding on hardened steel was studied using a pin-on-disc type machine. The effect of fibre orientation on wear rate was studied to provide wear resistance engineering data on the MMCs. Tests were carried out with the wear surface sliding direction set normal, parallel and anti-parallel to the fibre axis. Experiments were perfonned for sliding speeds of 0.6, 1.0 and 1.6 m/s for a load range from 12 N to 60 N. A number of sensitive techniques were used to examine worn surface and debris, i.e: Scanning Electron Microscopy (SEM), Backscattered Electron Microscopy (BSEM) and X-ray Photoelectron Spectroscopy (XPS). Finally, the effect of fibre orientation on the wear rate of the Borsic-reinforced plastic matrix composites (PMCs) produced by hot pressing technique was also investigated under identical test conditions. It was found that the composite had a markedly increased tensile strength compared with the matrix. The wear results also showed that the composite exhibited extremely low wear rates compared to the matrix material and the wear rate increased with increasing sliding speed and normal load. The effect of fibre orientation was marked, the lowest wear rates were obtained by arranging the fibre perpendicular to the sliding surface, while the highest wear was obtained for the parallel orientation. The coefficient of friction was found to be lowest in the parallel orientation than the others. Wear of PMCs were influenced to the greatest extent by these test parameters although similar findings were obtained for both composites. Based on the results of analyses using SEM, BSED and XPS, possible wear mechanisms are suggested to explain the wear of these materials.

Basisdiskothek Rock und Pop:Essential collection rock and pop

Was darf in einem gutsortierten Plattenschrank aus den Bereichen Rock und Pop nicht fehlen? Uwe Schütte beantwortet diese drängende Frage. Inzwischen hat er seine erfolgreiche Empfehlungsliste überarbeitet und den Band um fünf Klassiker sowie Entdeckungen in neuen Einzelartikeln ergänzt: von Abba über Burial, Death Cab For Cutie und Tocotronic bis hin zu Wilco. Register der Platten und Gruppen erleichtern die Orientierung in diesem für den Musikfan unentbehrlichen Band. What may be missing in a well-stocked record collection from the fields of rock and pop not? Uwe Schütte answers this pressing question. Since then he has revised his successful referral list and the band around five classics and new discoveries, supplemented in individual articles: Abba on Burial, Death Cab For Cutie and Plumb to Wilco. Register of the panels and groups to facilitate the orientation in this indispensable volume for the music lover.

An online assessment and development tool for business incubators:optimising business-incubation management practice, performance and impact, Project Report

This project is focused on exchanging knowledge between ABS, UKBI and managers of business incubators in the UK. The project relates to exploitation of extant knowledge-base on assessing and improving business incubation management practice and performance and builds on two earlier studies. It addresses a pressing need for assessing and benchmarking business incubation input, process and outcome performance and highlighting best practice. The overarching aim of this project was to obtain proof-of-concept for a business incubation performance assessment and benchmarking online tool, fine-tune it and put it in use by nurturing a community of business incubation management practice, aligned by the resultant tool. The purpose was to offer an appropriate set of measures, in areas identified by relevant research on business incubation performance management and impact as critical, against which: 1.The input and process performance of business incubation management practice can be assessed and benchmarked within the auspices of a community of incubator managers concerned with best practice 2.The outcome performance and impact of business incubators can be assessed longitudinally. As such, the developed online assessment framework is geared towards the needs of researchers, policy makers and practitioners concerned with business incubation performance, added value and impact.

Fracture toughness of some high density PM steels

Tensile strengths, impact energies, and fracture toughness data are presented for pure Fe-0.5 C, Astaloy A with 0.2 and 0.6%C, and for Distaloy AB-0.6%C at relative densities of about 0.9, achieved by conventional pressing and sintering, and at close to 1.0, achieved by powder forging. At low relative density, properties are controlled by sizes of sinter necks; it is postulated that toughness scales as (x/a)4, x/a being the ratio of neck diameter to particle diameter. At high relative density, microvoid coalescence and good toughness is observed for low strength microstructures whereas cleavage and poor toughness is a concomitant of high strength.

Hierarchical porous catalysts tailored for biodiesel production

There is a pressing need for sustainable transportation fuels to combat both climate change and dwindling fossil fuel reserves. Biodiesel, synthesised from non-food plant (e.g., Jatropha curcas) or algal crops is one possible solution, but its energy efficient production requires design of new solid catalysts optimized for the bulky triglyceride and fatty acid feedstocks. Here we report on the synthesis of hierarchical macroporous-mesoporous silica and alumina architectures, and their subsequent functionalization by propylsulfonic acid groups or alkaline earth oxides to generate novel solid acid and base catalysts. These materials possess high surface areas and well-defined, interconnected macro-mesopore networks with respective narrow pore size distributions tuneable around 300 nm and 5 nm. Their high conductivity and improved mass transport characteristics enhance activity towards transesterification of bulky tricaprylin and palmitic acid esterification, over mesoporous analogues. This opens the way to the wider application of hierarchical catalysts in biofuel synthesis and biomass conversion.

An actor-network theory study of public sector inter-organisational collaboration

EMBARGOED The literature on inter-organisational collaboration, although wide-ranging, offers little guidance on collaboration as process. It focuses in the main on human attributes like leadership, trust and agency, but gives little consideration to the role of objects in the development of inter-organisational collaborations. A central aim of this thesis is to understand the interaction of objects and humans in the development of a particular health and social care partnership in the North East of England. This socio-material perspective was achieved through actor-network theory (ANT) as a methodology, in which the researcher is equally sensitised to the role of human and non-human entities in the development of a network. The case study is that of the North East Lincolnshire Care Trust Plus (CTP). This was a unique health and social care collaboration arrangement between North East Lincolnshire Council and North East Lincolnshire Primary Care Trust, setup to address heath inequalities in the region. The CTP was conceived and developed at a local level by the respective organisation’s decision makers in the face of considerable opposition from regional policy makers and national regulators. However, despite this opposition, the directors eventually achieved their goal and the CTP became operational on 1st September 2007. This study seeks to understand how the CTP was conceived and developed, in the face of this opposition. The thesis makes a number of original contributions. Firstly, it adds to the current body of literature on collaboration by identifying how objects can help problematize issues and cement inter-organisational collaborations. Secondly it provides a novel account describing how two public sector organisations created a unique collaboration, despite pressing resistance from the regulatory authorities; and thirdly it extends Callon’s (1996) notion of problematization to examine how, what is rather vaguely described as ‘context’ in the literature, becomes enmeshed in decisions to collaborate. UNTIL 03/02/2016 THIS THESIS IS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY WITH PRIOR ARRANGEMENT

Source localization methods

One of the most pressing demands on electrophysiology applied to the diagnosis of epilepsy is the non-invasive localization of the neuronal generators responsible for brain electrical and magnetic fields (the so-called inverse problem). These neuronal generators produce primary currents in the brain, which together with passive currents give rise to the EEG signal. Unfortunately, the signal we measure on the scalp surface doesn't directly indicate the location of the active neuronal assemblies. This is the expression of the ambiguity of the underlying static electromagnetic inverse problem, partly due to the relatively limited number of independent measures available. A given electric potential distribution recorded at the scalp can be explained by the activity of infinite different configurations of intracranial sources. In contrast, the forward problem, which consists of computing the potential field at the scalp from known source locations and strengths with known geometry and conductivity properties of the brain and its layers (CSF/meninges, skin and skull), i.e. the head model, has a unique solution. The head models vary from the computationally simpler spherical models (three or four concentric spheres) to the realistic models based on the segmentation of anatomical images obtained using magnetic resonance imaging (MRI). Realistic models – computationally intensive and difficult to implement – can separate different tissues of the head and account for the convoluted geometry of the brain and the significant inter-individual variability. In real-life applications, if the assumptions of the statistical, anatomical or functional properties of the signal and the volume in which it is generated are meaningful, a true three-dimensional tomographic representation of sources of brain electrical activity is possible in spite of the ‘ill-posed’ nature of the inverse problem (Michel et al., 2004). The techniques used to achieve this are now referred to as electrical source imaging (ESI) or magnetic source imaging (MSI). The first issue to influence reconstruction accuracy is spatial sampling, i.e. the number of EEG electrodes. It has been shown that this relationship is not linear, reaching a plateau at about 128 electrodes, provided spatial distribution is uniform. The second factor is related to the different properties of the source localization strategies used with respect to the hypothesized source configuration.

Perspective work on optical fibre sensors

Optical fibre based sensors are transforming industry by permitting monitoring in hitherto inaccessible environments or measurement approaches that cannot be reproduced using conventional electronic sensors. A multitude of techniques have been developed to render the fibres sensitive to a wide range of parameters including: temperature, strain, pressure (static and dynamic), acceleration, rotation, gas type, and specific biochemical species. Constructed entirely of glass or polymer material, optical fibre devices like fibre gratings offer the properties: low loss, dielectric construction, small size, multiplexing, and so on [1-3]. In this paper, the authors will show the latest developing industrial applications, using polymer optical fibre (POF) devices, and comparing their performance with silica optical fibre devices. The authors address two pressing commercial requirements. The first concerns the monitoring of fuel level in civil aircraft. There is a strong motivation in the aerospace industry to move away from electrical sensors, especially in the fuel system. This is driven by the need to eliminate potential ignition hazards, the desire to reduce cabling weight and the need to mitigate the effects of lightning strikes in aircraft where the conventional metallic skin is increasingly being replaced by composite materials. In this case, the authors have developed pressure sensors based on a diaphragm in which a polymer fibre Bragg grating (POFBG) has been embedded [3]. These devices provide high pressure sensitivity enabling level measurement in the mm range. Also, it has developed an approach incorporating several such sensors which can compensate for temperature drifts and is insensitive to fluid density. Compared with silica fibre-based sensors, their performance is highly enhanced. Initial results have attracted the interest of Airbus from UK, who is keen to explore the potential of optical technology in commercial aircraft. The second concerns the monitoring of acoustic signals and vibration in the subsea environment, for applications in geophysical surveying and security (detection of unwanted craft or personnel). There is strong motivation to move away from electrical sensors due to the bulk of the sensor and associated cabling and the impossibility of monitoring over large distances without electrical amplification. Optical approaches like optical hydrophones [5] offer a means of overcoming these difficulties. In collaboration with Kongsberg from Norway, the authors will exploit the sensitivity improvements possible by using POF instead of silica fibre. These improvements will arise as a result of the much more compliant nature of POF compared to silica fibre (3 GPa vs 72 GPa, respectively). Essentially, and despite the strain sensitivity of silica and POFBGs being very similar, this renders the POF much more sensitive to the applied stress resulting from acoustic signals or vibration. An alternative way of viewing this is that the POF is better impedance-matched to the surrounding environment (water for the intended applications), because although its impedance is higher than that of water, it is nearly an order of magnitude smaller than that of silica. Finally, other future industrial applications will be presented and discussed, showing the vast range of the optical fiber devices in sensing applications.

Large-scale data for multiple-view stereopsis

The seminal multiple-view stereo benchmark evaluations from Middlebury and by Strecha et al. have played a major role in propelling the development of multi-view stereopsis (MVS) methodology. The somewhat small size and variability of these data sets, however, limit their scope and the conclusions that can be derived from them. To facilitate further development within MVS, we here present a new and varied data set consisting of 80 scenes, seen from 49 or 64 accurate camera positions. This is accompanied by accurate structured light scans for reference and evaluation. In addition all images are taken under seven different lighting conditions. As a benchmark and to validate the use of our data set for obtaining reasonable and statistically significant findings about MVS, we have applied the three state-of-the-art MVS algorithms by Campbell et al., Furukawa et al., and Tola et al. to the data set. To do this we have extended the evaluation protocol from the Middlebury evaluation, necessitated by the more complex geometry of some of our scenes. The data set and accompanying evaluation framework are made freely available online. Based on this evaluation, we are able to observe several characteristics of state-of-the-art MVS, e.g. that there is a tradeoff between the quality of the reconstructed 3D points (accuracy) and how much of an object’s surface is captured (completeness). Also, several issues that we hypothesized would challenge MVS, such as specularities and changing lighting conditions did not pose serious problems. Our study finds that the two most pressing issues for MVS are lack of texture and meshing (forming 3D points into closed triangulated surfaces).

Expanding the biomass resource:sustainable oil production via fast pyrolysis of low input high diversity biomass and the potential integration of thermochemical and biological conversion routes

Waste biomass is generated during the conservation management of semi-natural habitats, and represents an unused resource and potential bioenergy feedstock that does not compete with food production. Thermogravimetric analysis was used to characterise a representative range of biomass generated during conservation management in Wales. Of the biomass types assessed, those dominated by rush (Juncus effuses) and bracken (Pteridium aquilinum) exhibited the highest and lowest volatile compositions respectively and were selected for bench scale conversion via fast pyrolysis. Each biomass type was ensiled and a sub-sample of silage was washed and pressed. Demineralization of conservation biomass through washing and pressing was associated with higher oil yields following fast pyrolysis. The oil yields were within the published range established for the dedicated energy crops miscanthus and willow. In order to examine the potential a multiple output energy system was developed with gross power production estimates following valorisation of the press fluid, char and oil. If used in multi fuel industrial burners the char and oil alone would displace 3.9 × 105 tonnes per year of No. 2 light oil using Welsh biomass from conservation management. Bioenergy and product development using these feedstocks could simultaneously support biodiversity management and displace fossil fuels, thereby reducing GHG emissions. Gross power generation predictions show good potential.

Europe’s Growth Emergency

Highlights: • The European Union growth agenda has become even more pressing because growth is needed to support public and private sector deleveraging, reduce the fragility of the banking sector, counter the falling behind of southern European countries and prove that Europe is still a worthwhile place to invest. • The crisis has had a similar impact on most European countries and the US: a persistent drop in output level and a growth slowdown. This contrasts sharply with the experience of the emerging countries of Asia and Latin America. • Productivity improvement was immediate in the US, but Europe hoarded labour and productivity improvements were in general delayed. Southern European countries have hardly adjusted so far. • There is a negative feedback loop between the crisis and growth, and without effective solutions to deal with the crisis, growth is unlikely to resume. National and EU-level policies should aim to foster reforms and adjustment and should not risk medium-term objectives under the pressure of events. A more hands-on approach, including industrial policies, should be considered.

Patterns of diagnostic comorbidity in children and adolescents with anxiety

Comorbidity is defined as the co-occurrence of two or more psychological disorders and has been identified as one of the most pressing issues facing child psychologists today. Unfortunately, research on comorbidity in anxious children is rare. The purpose of this research was to examine how specific comorbid patterns in children and adolescents referred with anxiety disorders affected clinical presentation. In addition, the effects of gender, age and total number of diagnoses were also examined.^ Three hundred fifty-five children and adolescents (145 girls and 210 boys, hereafter referred to as "children") aged 6 to 17 who presented to the Child Anxiety and Phobia Program during the years 1987 through 1996 were assessed through a structured clinical interview administered to both the children and their families. Based on information from both children and parents, children were assigned up to five DSM diagnoses. Global ratings of severity were also obtained. While children were interviewed, parents completed a number of questionnaires pertaining to their child's overall functioning, anxiety, thoughts and behaviors. Similarly, while parents were interviewed, children completed a number of self-report questionnaires concerning their own thoughts, feelings and behaviors.^ In general, children with only anxiety disorders were rated as severe as children who met criteria for both anxiety and externalizing disorders. Children with both anxiety and externalizing disorders were mostly young (i.e. age 6 through 11) and mostly male. These children tended to rate themselves (and be rated by their parents) equally as anxious as children with only anxiety disorders. Global ratings of severity tended to be associated with the type of comorbid pattern versus the number of diagnoses assigned to a child. The theoretical, development and clinical implications of these findings will be discussed. ^

The effect of group counseling on the self-esteem, attendance, and counselor utilization of immigrant Hispanic secondary limited English proficient students

As the population of the United States becomes more diverse and the immigrant Hispanic, limited English proficient (LEP) school age population continues to grow, understanding and addressing the needs of these students becomes a pressing question. The purpose of this study was to investigate the effects of group counseling, by a bilingual counselor, on the self-esteem, attendance and counselor utilization of Hispanic LEP high school students. The design for this study was a quasi-experimental design. The experimental and control groups consisted of one class from each of the four levels of English for Speakers of Other Languages (ESOL), I-IV. The counseling intervention, the independent variable, was delivered by a bilingual counselor once a week, for fifteen weeks.^ A total of 112 immigrant Hispanic LEP students selected from the total ESOL student population participated in the study. The experimental and control groups were administered the Culture Free Self Esteem Inventory (CFSEI) Form AD as a pretest and posttest. The Background Information Questionnaire (BIQ) was utilized to gather information on counselor utilization and demographic data. Attendance data were obtained from the students' computer records. At the conclusion of the study the differences between the experimental and control groups on the three dependent variables were compared.^ Statistical analyses of the data were done using SPSS statistical software. A multivariate analysis of variance (MANOVA) was utilized to determine if there were significant differences in the self-esteem scores, attendance and counselor utilization. Correlational analyses was utilized to determine if there was a relationship between English language proficiency and self-esteem and between acculturation level and self-esteem.^ The study results indicate that there were no significant differences in the self-esteem scores and attendance of the subjects in the experimental group at the completion of the group counseling treatment. Counselor utilization was statistically significant for the targeted population. A relationship was found between English language proficiency level and self-esteem scores for students in ESOL levels II, III and IV. No significant correlation was found between acculturation and self-esteem.^ Research on the dropout rates of LEP coupled with the results of this study show that students at the intermediate and advanced levels of ESOL (III and IV) exhibit more positive self-esteem and achieve higher graduation rates that levels I and II. LEP students at levels I and II, once they became familiar with the role and function of school counselors through group counseling, utilized their services. ^

Norms and Greek foreign policy: 1981--2000

From the end of WWII to the end of the Cold War Greek foreign policy was shaped by the dynamics of the Cold War. The major issues facing Greek foreign policy decision makers in the post-cold war era are its relations with its Northern neighbors, Albania, The Former Yugoslav Republic of Macedonia (FYROM), and Bulgaria, its relations with Turkey, and Greece's future in the European Union. Although the three issues overlap there is consensus among the Greek political elite that the relationship with Turkey is the most pressing since Turkey poses the most immediate security threat. In the last twenty-five years the two countries came to the verge of war three times over the continental shelf in the Aegean and Cyprus. The latest crisis was in 1996. Since then Greek policy makers have embarked on a conciliatory road towards Turkey that has gained momentum in the last three years. The purpose of this dissertation is to describe the process of the recent change in Greek foreign policy vis-à-vis Turkey, as reflected in the words and deeds (speeches, interviews, statements, policies) of the Greek policy makers. In addition, the study seeks to understand how this change is related to rules existing at the global, regional, and domestic levels. The central question to be asked is: how do rules existing at these levels regulate and constitute the foreign policy process of the Greek government. I utilize the theoretical insights and concepts provided by constructivism in order to carry out my research. The analysis establishes the relationship between the agents (Greek foreign policy makers) and the various rules and explores this relationship as an ongoing process by ascertaining the social context within which this process is unfolding. ^

Actionable pattern analysis in computing and business intelligence systems

With advances in science and technology, computing and business intelligence (BI) systems are steadily becoming more complex with an increasing variety of heterogeneous software and hardware components. They are thus becoming progressively more difficult to monitor, manage and maintain. Traditional approaches to system management have largely relied on domain experts through a knowledge acquisition process that translates domain knowledge into operating rules and policies. It is widely acknowledged as a cumbersome, labor intensive, and error prone process, besides being difficult to keep up with the rapidly changing environments. In addition, many traditional business systems deliver primarily pre-defined historic metrics for a long-term strategic or mid-term tactical analysis, and lack the necessary flexibility to support evolving metrics or data collection for real-time operational analysis. There is thus a pressing need for automatic and efficient approaches to monitor and manage complex computing and BI systems. To realize the goal of autonomic management and enable self-management capabilities, we propose to mine system historical log data generated by computing and BI systems, and automatically extract actionable patterns from this data. This dissertation focuses on the development of different data mining techniques to extract actionable patterns from various types of log data in computing and BI systems. Four key problems—Log data categorization and event summarization, Leading indicator identification , Pattern prioritization by exploring the link structures , and Tensor model for three-way log data are studied. Case studies and comprehensive experiments on real application scenarios and datasets are conducted to show the effectiveness of our proposed approaches.