Structural, Field Emission and Ammonia Gas Sensing Properties of Multiwalled Carbon Nanotube-Graphene Like Hybrid Films Deposited by Microwave Plasma Enhanced Chemical Vapor Deposition Technique

This paper reports the direct deposition of multiwalled carbon nanotube (MWCNT)-graphene like hybrid films on nickel substrate using a 2.45 GHz microwave plasma enhanced chemical vapor deposition (MW PECVD) system in the temperature range of 500-700 degrees C at 20 Torr pressure. The films have been characterized by Raman spectra, high resolution transmission electron microscope (HRTEM), scanning electron microscope, high resolution X-ray diffraction and contact angle measurement. Raman spectroscopy and HRTEM reveal the formation of MWCNT and graphene like hybrid carbon sheet structures. The effect of processing temperature on the field emission properties of MWCNT-graphene like hybrid films has been investigated. Field emission measurement reveals that the turn-on field decrease and the emission current density increase with the increase of deposition temperature. The rambutan structure of MWCNT formed at 700 degrees C is responsible for the improvement in the field emission properties. The film deposited at 700 degrees C shows fast response and recovery time of 40 and 96 s, respectively, for ammonia gas sensing due to the high surface area of the film. It has also been found that the hydrophobic surface of the film helps to perform the gas sensing in the humid environment

A Portfolio of Academic, Therapeutic Practice and Research Work Including An Investigation of the Narratives of Adults Bereaved by Parental Suicide in Childhood.

This portfolio is comprised of three dossiers which reflect the academic, clinical and research work that form part of the Practitioner Doctorate (PsychD) in Psychotherapeutic and Counselling Psychology. The academic dossier is made up of three essays. The first essay explores the concept of countertransference in psychodynamic play therapy with children. The second essay examines the use of the psychodynamic concept of countertransference in Cognitive Behavioural Therapy. The third essay critically discusses the diagnostic category of Gender Identity Disorder and considers the implications for therapy. The therapeutic practice dossier includes a description of my clinical placements over my four years of training. It also contains a piece entitled 'My final clinical paper' which gives an account of my personal and professional development and emerging identity as a counselling psychologist. The final dossier holds three pieces of research all of which explore the experience of parental suicide and its relevance to therapeutic practice. The first piece is a literature review which investigates the nature of grief for children bereaved by parental suicide and the potential impact on identity. The second is an empirical piece which explores the narratives of adults bereaved by parental suicide in childhood. Five participants were interviewed and the method of narrative analysis was employed to analyse the data. Clinical implications and recommendations for future research were also discussed. The third and final research paper investigated the experience of parenthood for adults bereaved by parental suicide in childhood. Semistructured interviews were conducted with four individuals and the data subjected to Interpretative Phenomenological Analysis

Models for continuous improvement of productivity and quality

During the last decade there has been a tremendous revolution in quality management practices. These changes have come as a result of the necessity to change in a globally competitive environment rather as a result of any major breakthrough in science or technology. This dissertation focuses on problems that will assist the firm in increasing its productivity and improving the quality of the product. We first consider the problem of optimal allocation of work in an assembly system, we examine a PUSH system. The problem corresponds to moving work between feeder stations and the assembly station to achieve the optimal workload that will maximize expected throughput. For this configuration, earlier studies showed that optimal expected throughput decreased as the number of feeder stations increased for exponential and log-normal processing times. However, the pattern was not similar for uniform processing times, where, the optimal throughput initially decreased and then increased as the number of components increased. We provide insights as to the causes of this seemingly anomalous behavior described for the uniform processing time distribution. We also investigate the impact of unbalancing on the variability of interdeparture time (reciprocal of throughput) and observe that the variability of interdeparture time decreases due to unbalancing. Further, we investigate a more realistic case that considers the assembly time as a function of the number of components. Next, we consider a manufacturing environment where process improvement activities require use of the productive capacity of the firm in addition to other investments. Thus, the firm must allocate its productive capacity between production activities and improvement activities. The output of production activities is used to meet customer demand. Process improvement activities improve the quality of the output, which in turn leads to lower quality related costs (both internal and external) and possibly lower per-unit production cost. A continuous time, finite horizon, profit maximization, resource allocation model is developed to find an optimal time path for process improvement activities and production activities. Lastly, we consider acceptance sampling plans using Bayesian techniques and subject to measurement error. Prior work has shown that Taguchi\u27s quadratic loss function is superior to the step-loss function and Bayesian sampling plans are more appropriate. Impact of measurement error is significant and the assumption of no measurement error should be reconsidered. In this section, we develop two Bayesian lot-by-lot variable acceptance sampling plans, subject to measurement error, using the Taguchi loss function for measuring the loss due to imperfect quality. We conduct a sensitivity analysis of the models with respect to the cost of rejection or rework, the quadratic cost of quality, the correlation between the observed deviation and the actual deviation of the performance variable, and the measurement error, and obtain some interesting counterintuitive results. These models incorporate the concept of continuous improvement of productivity and quality through learning

A Portfolio of Academic, Therapeutic Practice and Research Work Including An Investigation of the Narratives of Adults Bereaved by Parental Suicide in Childhood.

This portfolio is comprised of three dossiers which reflect the academic, clinical and research work that form part of the Practitioner Doctorate (PsychD) in Psychotherapeutic and Counselling Psychology. The academic dossier is made up of three essays. The first essay explores the concept of countertransference in psychodynamic play therapy with children. The second essay examines the use of the psychodynamic concept of countertransference in Cognitive Behavioural Therapy. The third essay critically discusses the diagnostic category of Gender Identity Disorder and considers the implications for therapy. The therapeutic practice dossier includes a description of my clinical placements over my four years of training. It also contains a piece entitled 'My final clinical paper' which gives an account of my personal and professional development and emerging identity as a counselling psychologist. The final dossier holds three pieces of research all of which explore the experience of parental suicide and its relevance to therapeutic practice. The first piece is a literature review which investigates the nature of grief for children bereaved by parental suicide and the potential impact on identity. The second is an empirical piece which explores the narratives of adults bereaved by parental suicide in childhood. Five participants were interviewed and the method of narrative analysis was employed to analyse the data. Clinical implications and recommendations for future research were also discussed. The third and final research paper investigated the experience of parenthood for adults bereaved by parental suicide in childhood. Semistructured interviews were conducted with four individuals and the data subjected to Interpretative Phenomenological Analysis

Easy synthesis of organic-inorganic hybrid nanomaterials: study of DC conduction mechanism for light dependent resistors

A surfactant assisted chemical oxidation method has been employed for facial synthesis of polypyrrole/tin oxide (PPy/SnO2) hybrid nanoneedles. The charge transport properties of the prepared hybrid nanomaterials have been analyzed under different conduction mechanisms for their possible application for light dependent resistors (LDRs). The scanning electron microscopy studies revealed that the increased concentration of additive SnO2 quantum dots alters the surface morphology from nanowall-like to nanoneedle-like and the formation of PPy/SnO2 nanocomposites is confirmed X-ray diffraction studies. The strong coupling between the PPy and SnO2 results in the transformation of PPy from highly oxidized states to oxidized states and is confirmed through Raman analysis. The simple band conduction model and Kivelson's power law based conduction mechanism could not be applied to explain the conduction mechanism due to different reasons. The log sigma(dc) curves for all samples were well fitted for gamma = 1/4, suggesting the applicability of Mott's three dimensional variable range hopping VRH model for charge transport. The room temperature dark conductivity of the samples was found to decrease with an increase in SnO2 concentration. The formation of p-n junctions between p-type PPy and n-type SnO2 changes the bandgap of PPy and the work function. This modifies the electronic structure of PPy which brings a synergistic effect in the photosensitivity of the PPy/SnO2 nanocomposites. The room temperature photoresponse of the PPy/SnO2 samples was found to increase from 2.85 to 6.25% at 100 mW cm(-2) illumination intensity with an increase in the SnO2 doping concentration from 0 to 20%

Influence of consumed power on structural and nano-mechanical properties of nano-structured diamond-like carbon thin films

Mixed Ar-C2H2 plasma was characterized by VI probe for estimating the actual consumed power (CP) in the plasma and its effect on diamond-like carbon (DLC) thin films deposited at different CPs in the range 1685 W. The structural properties of the films were examined using variety of spectroscopic and microscopic techniques, such as Fourier Transform Infrared spectroscopy, X-ray Photoelectron Spectroscopy, Micro-Raman Spectroscopy and Atomic Force Microscopy. The film deposited at 36 W CP showed the formation of nano-structure, creation of optimum sp(3)/sp(2) bonding ratio and excellent nano-mechanical properties with the maximum hardness of similar to 28.2 GPa. However, the nano-mechanical properties of the films got altered with the variation of CP, which is attributed to the changes seen in the structural properties. These findings show that high quality DLC films with higher hardness can be deposited by monitoring and controlling the process parameters of the plasma

Effect of high substrate bias and hydrogen and nitrogen incorporation on density of states and field-emission threshold in tetrahedral amorphous carbon films

This article reports the influence of substrate bias during growth and of hydrogen and nitrogen incorporation on density of states [N (EF)] and field-emission threshold (Eturn-on) in tetrahedral amorphous carbon (ta-C) films, deposited using an S-bend filtered cathodic vacuum arc process. The variation in negative substrate bias from −20 to −200 V was found to initially lead to a small decrease in N (EF) and Eturn-on, and a small increase in the emission current density (J) at 12.5 V/μm in the case of as-grown ta-C films; beyond −200 V substrate bias there is a reversal in the trend. The values of N (EF) = 1.3×1017 cm−3 eV−1, Eturn-on = 8.3 V/μm, and J = 6.19 mA/cm2 were observed at −200 V substrate bias. However at −300 V the properties were not very different from those at −200 V substrate bias and so with a view to use the higher energy, hydrogen and nitrogen incorporation studies were carried out in this condition. It was observed that there was further enhancement in properties with hydrogen and nitrogen incorporation. The best properties measured with in the range of hydrogen and nitrogen incorporation in the present study were N (EF) = 8.0×1016 cm−3 eV−1, Eturn-on = 7.6 V/μm, and J = 23.7 mA/cm2, respectively

Effect of ambient gaseous environment on the properties of amorphous carbon thin films

Amorphous carbon films have been deposited by filtered cathodic jet carbon arc technique under different gaseous environments. Scanning electron microscope and atomic force microscope studies have been performed on the deposited films for the surface morphological studies. The morphology of the deposited film changes with the change in gas environment. X-ray photoelectron spectroscopic (XPS) and Raman studies have been carried out on the deposited samples for the evaluation of the chemical bonding of carbon atoms with the ambient gas atoms. The sp3 and sp2 contents have been evaluated from the XPS studies and found to be dependent on the gaseous environment. The film deposited under hydrogen environment has the highest value of the sp3 content (54.6 at.%) whereas the film deposited under helium environment has the lowest value of sp3 content (37 at.%). For the evaluation of the electrical and mechanical properties of the deposited films, the electrical conductivity and nanoindentation measurements have been performed on the deposited films. It has been observed that the film deposited under helium environment has the highest electrical conductivity and the lowest hardness (∼15 GPa) value whereas film deposited under hydrogen environment has the highest hardness (∼21 GPa) and the lowest conductivity