Metal to ceramic joining for high temperature applications

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The phenomenal growth rate for the use of engineering ceramics is attributed to successful scientific responses to industrial demand. These materials are replacing metal and its alloys in diverse applications from cutting tools and heat engine components to integrated circuits. Joining technology plays a vital role in this changing and evolving technology as success and failure comes with breaking new barriers. It is important to improve existing techniques and to develop new techniques that reliably join simple shape components to form complex assemblies or join dissimilar materials such as metal to ceramic. Joining of ceramics is not simple due to their high chemical stability and low coefficient of thermal expansion (CTE). Joining between metal and ceramic is usually carried out at elevated temperatures and upon cooling thermal residual stresses are induced that lead to joint failure or poor strength. Most metal-ceramic joints cannot be used over 500°C primarily due to the low melting temperature of the interlayer. This investigation was concerned with the successful joining for higher temperature applications (above 500°C) of two dissimilar high temperature oxidation and corrosion resistant materials, Fecralloy and silicon nitride. The primary focus was on the effects of process conditions upon the microstructure and mechanical properties of the joint and to also study/identify the joining mechanism. Two novel techniques were employed to join successfully the metal to ceramic. The first was by use of a thin Cu foil that did not remain after joining. Joining occurs by a process that results in partial melting of the Fecralloy interface, where Fe, Cr, Al and Cu reactively infiltrate into the silicon nitride. This liquid mixture causes partial dissolution of the silicon nitride interface, where Si and N diffuse into the Fecralloy. A thin reaction product layer was formed at the silicon nitride interface and our results suggested that this was AIN. The free surface Si and porosity of the silicon nitride along with the eutectic temperatures above 1100°C are all vital for this joining process. The highest average shear strength of a Fecralloy-silicon nitride joint produced by the method was 67.5 MPa. The second route was that of a powder metallurgy one, where cold pressed Ni-Al (1:1 molar) compacts were used to join successfully the Fecralloy to silicon nitride. The formation of NiAl from its constituents is highly exothermic and this is initiated between 500-650°C. The high temperature reached causes partial melting of the Fecralloy interface and dissolution/reactive wetting at the silicon nitride interface. Mostly Fe infiltrates the NiAl improving room temperature ductility, fracture toughness and yield strength. Molten Al from the interlayer reacts and wets the silicon nitride interface with small amount of infiltration and no reaction product forming. The reaction synthesis of NiAl was studied using DTA and TGA, where the effects of Ni particle size and heating rate were investigated. This joining process is highly dependant upon process conditions, the most important of which are applied pressure, heating rate and Ni/A1 particle size. The highest average shear strength attained was 94.30 MPa and this is attributed to good interfacial bonding, high pressure, moderate process temperature and dwell time. The exothermic formation of the NiAl interlayer that is densified and monophase was paramount for this joining process. The Bansal-Doremus kinetic model for evaluating the kinetic parameters from non-isothermal DTA data was shown to be valid. The results obtained were identical to those by other authors who used a different model and approach

How do Project Teams impact on project success, A case of Heathrow Terminal 2

2013 dissertation for MSc in Project Management. Selected by academic staff as a good example of a masters level dissertation. TPurpose – The purpose of the research was to determine how do project teams impact on project success. Although, there exists a plethora of organisational and project management literature on soft side of project management, but there is still need for more in-depth examination of those critical success factors which either drive the project towards successful completion or otherwise failure to attain desired outcome(s) of project(s). Design/Methodology/Approach – To find out how do project teams impact on project success. This research study used structured questionnaire surveys to collect the responses from project teams currently, working on the Heathrow Terminal 2 project. Findings – The findings of the study revealed that some of the variables predicted from other literatures (clear goals, leadership and senior management support, communication and motivation) were significantly linked to the outcomes of the project. However, some key success factors or some key drivers were not paid sufficient consideration. Research Limitations/Implications – Limitations of the study included, for this research the data from 23 respondents from the project teams working on Heathrow Terminal 2 project was collected and analysed. This research can further be expanded to increase the size of data and diversity of participants. Further to this, the analysed factors for the study which significantly impacts project outcome(s) can vary from project to project; organisation to organisation and level of leadership. Practical implications – The findings of the study suggest that effective management of personnel (project teams) can drive the project towards either successful completion or otherwise failure to attain goals/objectives of the project. Originality/value – This research determines by exploring whether the effectively and efficiently managing the team practices are generic and impacts the project outputs positively or vice-versa

078— Bone Fracture Repair: Testing Porous Properties of Calcium Phosphate Bioactive Cement and How it Compares to Pig Bone

Autografting is the most effective method used for supplementing and replacing bone. Autografting is a risky procedure because of its invasive nature. When performing the procedure of autografting, one needs to remove small sections of bone to use as a stimulant at the fracture site. This study is made to design an alternative method to replace autografting. In our study, we used pig fibula as a model to compare the properties of our novel cement which is Calcium Phosphate based. Calcium Phosphate Cement (CPC) is ideal because it is a biocompatible bone substitute composed of hydroxyapatite (HA), which constitutes a major component of human bone. The hydroxyapatite will serve as the base ingredient for the cement. The cement allows for the successful osseointegration and the initiation of bone growth. We focus our efforts into understanding and finding a consistent porosity size between the bone and the cement. This will be done by using different concentrations of chitosan and sodium bicarbonate. Results of the experiment show that the sample most similar to the bone sample was the chitosan

Ownership Concentration and Firm Performance: Evidence from Pakistan

The current study aims to investigate the relationship between ownership concentration and firm performance. The study conducted the analysis on 262 non-financial listed firms on the Karachi stock exchange (KSE) for a time period of six years (2006-2011). The ownership concentration was measured through the percentage of shareholding by largest shareholder, five largest shareholders and ten largest shareholders, whereas firm performance was measured through market base performance parameters (Tobin’s Q) and accounting base performance parameter (ROA and ROE). The study employed multiple regression models to examine the relationship between ownership concentration and firm performance. The results revealed that ownership concentration has positive impact on firm performance for both accounting and market base performance parameters. The understanding of relationship dynamics of ownership concentration and firm performance helps investors and policy makers to better utilize the corporate governance internal control mechanisms for achieving the firm’s value maximization objective. Key Words: Ownership Concentration, Firm Performance, and Emerging Markets

Evaluation of Drinking Water Quality in Erbil City Kurdistan, Region-Iraq

This study is based on an analysis of drinking water characteristics in Erbil in Kurdistan. For water quality analysis Erbil is divided into four parts (Ifraz l, Ifraz ll, Ifraz lll and Bakhtari and Ainkawa wells). Several samples were collected which include three samples from source, five samples from wells, and 32 samples from houses. The physiochemical parameters of  , turbidity, conductivity, total hardness, and total alkalinity were analyzed. Cations potassium, calcium and sodium were also analyzed. In addition, anions chloride, nitrate and sulphate were analyzed. Further, the biological parameters of total coliform (thermo tolerant (faecal) coliform and faecal (streptococci)) were analyzed. There was no bacteria in the drinking water. All the parameters were in permissible limits. The range of pH (7.1-7.9), conductivity (282-850µ/s), turbidity (0.2-9.9mg/L), total hardness (188-407mg/L), total dissolved solids (141-360mg/L), and alkalinity was (121-378mg/L). Cations concentration range of calcium (50-102ppm), sodium (4.5-79ppm), potassium (1-5.2ppm). Anions concentration range of chloride (2.1-50ppm), sulphate (5-112ppm), nitrate 1.2-84ppm. While in ground water samples biological contamination has been found. The results indicate that the drinking water quality of Erbil is suitable. Keywords Evaluation, drinking water, physiochemical, biological, Erbil

Risk Factors of Intracerebral Hemorrhage – A Cross Sectional Study

ABSTRACT Background and Objective: Stroke is the major cause of disability and one of the top causes of death in the globe. Though the rate is decreasing in the West, it is most likely growing in Asia. In Pakistan, the burden of stroke risk factors is substantial. Although data on the incidence and prevalence of stroke in Pakistan is limited, there are several published case studies demonstrating major disparities in stroke epidemiology, risk factors, kinds, and patterns. This study aims to identify risk factors of intracerebral hemorrhage among patients presenting to a teaching hospital. Methods: From August 2019 to February 2020, 103 patients from DHQ Teaching Hospital Abbottabad\u27s medical units participated in this prospective cross-sectional research. A CT scan of the brain was performed in all patients to identify intra cerebral hemorrhage and was used to diagnose cerebrovascular events. In patients with intracerebral hemorrhage, detailed histories and medical records were thoroughly examined in order to identify risk factors such as uncontrolled hypertension. To detect poorly managed diabetes and hyperlipidemia, fasting blood glucose, fasting serum cholesterol, and fasting triglycerides were measured. SPSS 20 was used to evaluate the data obtained on a standardized proforma. Results: The majority of the patients (n=41) were over 70 years old, with 71 (68.93%) males and 32 (31.07%) females. Intracerebral hemorrhage was reported in 8.74 percent (n=9) of patients with acute cerebrovascular accidents, with 66.67 percent (n=6) having uncontrolled hypertension, 44.44 percent (n=4) having diabetes, and 33.33 percent (n=3) having hyperlipidemia. Conclusion: Intracerebral hemorrhage is prevalent in individuals who have had a cerebrovascular accident, and hypertension is the most common risk factor for this consequenc

ECONOMIC VALUE ADDITION IMPLICATIONS: A STUDY OF THE PAKISTANI BANKING INDUSTRY

Human beings are mostly concerned about value additionin almost every aspect of life. Does this reality prove accurate insecondary markets investment? This empirical study deals with theEconomic Value Addition of major seventeen banks of Pakistanincluding national and public limited banks. In this research, ROE,ROCE, and OCF are taken as parameters of profitability whilemarketability parameters are PE and MB ratio. Two sample t-testsshow that a new banks value creation is more in comparison withold banks in the context of EVA. Private and Government bank arenot significantly different in EVA. Fixed effect modeling and Clusterestimation infer that Profitability parameters positively impact EVA.Marketability parameter MB positively impacts EVA while PE ratiois statistically insignificant. Correlation analysis shows thatinvestors of the banking sector in Pakistan do not pay specialattention to EVA in their investment decisions

Individual Investments Biased by the Size of a Foreign Investor: An Experimental Study

The field of behavioral finance has actively researched behavioral elements influencing the choices of individual investors. This study also contributes to the behavioral finance and examines the effect of an increase in a foreign firm’s partial ownership in a domestic firm on the local individual investments in that domestic firm. Specifically, using a controlled lab experiment the study examines the investments of Pakistani individual investors between a purely Pakistani firm and a Pakistani firm with three different levels of Chinese ownership (portfolio, minority, majority). The experimental results show that with reference to Chinese minority ownership in a Pakistani firm, the potential investors are 47% (61%) less likely to invest in a Pakistani firm with Chinese portfolio (majority) ownership than in a purely Pakistani firm. The study uncovers an important non-monetary factor in the form of a foreign firm’s partial ownership that can significantly influence the choices of individual investors. It also makes an important contribution to the growing literature on the Chinese foreign investments specifically in Pakistan by exploring how potential individual Pakistani investors are likely to react to an increase in Chinese investments in Pakistani firms

Oil Recovery from Petroleum Sludge by Solvent Extraction Method

Industries developed during the last decades and the importance of oil is increasing. Petroleum is one of the most valuable non-renewable sources and it also, has the biggest effects on the environments after coal. Crude oil became the goal of many countries in order to increase their economies income, despite the outcome that has towards the environment. The crude oil that passes through the refinery process produces a large amount of waste, which is call petroleum sludge. The sludge has countless disadvantage that cause environmental hazards due to its remediation effects. In addition, it is very valuable energy and it can be recovered. So the companies used several methods in order to use this source and get benefit from it. One of the methods is the solvent extraction method and overall, this method can decrease the effect of the petroleum sludge on the environment but not that much. However, it can recover the waste and turn it to useful energy. The recovery can be done by different steps. The first step is making chemical compositions before using the instruments. Second step is to use the centrifuge machine which will separate the sludge and recover it into oil, sludge sediment and water. The third part is to use the residual carbon machine which will measure the solidcontent inside the sludge and it will help us to find the violate and non-violate hydrocarbons. Finally using the GC which is gas chromatography that checks the quality of the petrol and also the composition substance.