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Engagement climate in service settings
Get PDFThis study explores the issue of drivers of service employee behaviour and performance, as antecedents of customer experiences that constitute key strategic outputs for service organizations. A proposed new construct, Engagement Climate, was developed and put forth as the "behavioural foundation" that the Service Climate model needs in the prediction of service employee behaviour and performance. The construct stems from the interpretation of engagement as an affect-based motivational process, and from the conceptualization of its antecedents as a specific type of psychological climate. Engagement Climate comprises a set of affectively charged psychological perceptions of the work environment, or engagement climate dimensions, which are conducive to the experience of engagement, a motivational state that triggers the investment of personal resources into the job role. Engagement Climate, as a latent social psychological construct, should virtually transcend the context of any one organisation or sector. However, given the nature of service work, Engagement Climate may most readily be observed (and fostered) in the context of services, in particular among front-line employees.The empirical study, consisting of a cross-sectional statistical survey, aimed to develop and pilot-test a questionnaire measure of Engagement Climate and to investigate its factor structure within a service organization. Data were collected from a total of 544 travel agents from a leading travel group in Spain. The factorial validity of the model comprising ten dimensions, namely Autonomy, Supervisor support, Clarity, Cohesion, Fairness, Trust, Challenge, Recognition, Self-expression, and Overload, was demonstrated using confirmatory factor analyses (CFA). The scale and subscales comprising the measurement model all showed good internal consistency and reliability values. Also, the hypothesized direct effects of engagement climate on personal engagement, as well as the relatively weaker effect of engagement climate on job satisfaction, were both confirmed using structural equation modelling (SEM).This study explores the issue of drivers of service employee behaviour and performance, as antecedents of customer experiences that constitute key strategic outputs for service organizations. A proposed new construct, Engagement Climate, was developed and put forth as the "behavioural foundation" that the Service Climate model needs in the prediction of service employee behaviour and performance. The construct stems from the interpretation of engagement as an affect-based motivational process, and from the conceptualization of its antecedents as a specific type of psychological climate. Engagement Climate comprises a set of affectively charged psychological perceptions of the work environment, or engagement climate dimensions, which are conducive to the experience of engagement, a motivational state that triggers the investment of personal resources into the job role. Engagement Climate, as a latent social psychological construct, should virtually transcend the context of any one organisation or sector. However, given the nature of service work, Engagement Climate may most readily be observed (and fostered) in the context of services, in particular among front-line employees.The empirical study, consisting of a cross-sectional statistical survey, aimed to develop and pilot-test a questionnaire measure of Engagement Climate and to investigate its factor structure within a service organization. Data were collected from a total of 544 travel agents from a leading travel group in Spain. The factorial validity of the model comprising ten dimensions, namely Autonomy, Supervisor support, Clarity, Cohesion, Fairness, Trust, Challenge, Recognition, Self-expression, and Overload, was demonstrated using confirmatory factor analyses (CFA). The scale and subscales comprising the measurement model all showed good internal consistency and reliability values. Also, the hypothesized direct effects of engagement climate on personal engagement, as well as the relatively weaker effect of engagement climate on job satisfaction, were both confirmed using structural equation modelling (SEM)
Atmospheric non-thermal plasma discharges for cleaning and bio-decontamination
Get PDFIt has been shown that non-thermal plasma has great potential for chemical oxidation and bacterial inactivation. However, the mechanism of plasma-induced oxidation and bactericidal effects is not fully understood, and optimisation of the non-thermal plasma treatment is required to improve the efficiency of this technology. This research presents an investigation into the oxidation and bio-decontamination capabilities of steady-state corona discharges and impulsive transient plasma discharges in atmospheric air. Degree of decolorisation of blue dye by plasma discharges was obtained and used for evaluation of the oxidation efficiency of these discharges. The Gram-positive and Gram-negative bacteria, Staphylococcus aureus and Escherichia coli, respectively, were used for investigation of the bio-decontamination capability of the plasma discharges. It has been shown that conditions such as air humidity, electrode topology, and voltage levels may affect the efficiency of plasma treatment.;The obtained results show that the oxidation and inactivation effects depend on the amount of charge delivered by the plasma. The charge-dependent decolorisation and inactivation rates of plasma discharge treatment, which indicate the oxidation efficiency and inactivation efficiency, were obtained and analysed. Different decolorisation and inactivation rates were achieved with various electrode topologies and energisation polarities. This study also investigated the production of reactive species by atmospheric plasma discharges. Ozone concentration was measured during the decolorisation and inactivation tests. The production of OH radicals by the plasma discharges have also been obtained in this study using terephthalic acid as the chemical probe.;The obtained results confirm that the reactive oxygen species play a major role in the plasma discharge treatment. In addition, an attempt of using TiO2 as a catalyst to enhance oxidation and bio-decontamination effects of the plasma discharge treatment has been made. TiO2 was revealed to have the potential to improve the oxidation efficiency of atmospheric plasma discharges. The results obtained and presented in this thesis will help in optimisation of non-thermal plasma systems for chemical and biological decontamination.It has been shown that non-thermal plasma has great potential for chemical oxidation and bacterial inactivation. However, the mechanism of plasma-induced oxidation and bactericidal effects is not fully understood, and optimisation of the non-thermal plasma treatment is required to improve the efficiency of this technology. This research presents an investigation into the oxidation and bio-decontamination capabilities of steady-state corona discharges and impulsive transient plasma discharges in atmospheric air. Degree of decolorisation of blue dye by plasma discharges was obtained and used for evaluation of the oxidation efficiency of these discharges. The Gram-positive and Gram-negative bacteria, Staphylococcus aureus and Escherichia coli, respectively, were used for investigation of the bio-decontamination capability of the plasma discharges. It has been shown that conditions such as air humidity, electrode topology, and voltage levels may affect the efficiency of plasma treatment.;The obtained results show that the oxidation and inactivation effects depend on the amount of charge delivered by the plasma. The charge-dependent decolorisation and inactivation rates of plasma discharge treatment, which indicate the oxidation efficiency and inactivation efficiency, were obtained and analysed. Different decolorisation and inactivation rates were achieved with various electrode topologies and energisation polarities. This study also investigated the production of reactive species by atmospheric plasma discharges. Ozone concentration was measured during the decolorisation and inactivation tests. The production of OH radicals by the plasma discharges have also been obtained in this study using terephthalic acid as the chemical probe.;The obtained results confirm that the reactive oxygen species play a major role in the plasma discharge treatment. In addition, an attempt of using TiO2 as a catalyst to enhance oxidation and bio-decontamination effects of the plasma discharge treatment has been made. TiO2 was revealed to have the potential to improve the oxidation efficiency of atmospheric plasma discharges. The results obtained and presented in this thesis will help in optimisation of non-thermal plasma systems for chemical and biological decontamination
An empirical feasibility assessment for incremental sheet forming
Get PDFMany sheet forming processes such [sic] hammering and spinning, have been used in the manufacturing industry for decades and consequently have strengths and weakness that are well known. In contrast, Incremental Sheet Forming (ISF) is an emerging type of forming process whose capabilities are not yet fully understood. So while it is clear that ISF processes have several advantages, such as low cost and good surface finish [sic]. It has proved difficult to define the limits of the process in terms of macro-parameters such as deformation and sheet thickness. So whereas the capabilities of many sheet metal manufacturing processes are effectively characterized by forming limit curves this has not been possible with ISF. In other words, there is a lack of methodologies for assessing the feasibility of using ISF for particular components. This thesis investigates several aspects of the ISF process and develops a quantitative methodology that allows a first approximation of the feasibility of component manufacturing using the ISF process in terms of deflection and thickness reduction. It was found that thickness reduction can be accurately modeled in terms of analytical model developed for sheet metal forming. The predictions of the method are assessed and found to give a good correspondence with measured data for the range of wall angles, materials and geometries assessed. The parameters of the proposed methodology have been determined by experimental studies of commercially pure Titanium Grade 4 (CpTi), Aluminium alloys (AA1050-H-14, AA2024-O and AA7075-O) and Stainless Steel (SS304-L) to understand the process of incremental sheet forming and its impact on the final properties of the sheet metal. The proposed method called "ISF-FCheck" uses two charts to quantify maximum strain in relation to the depth and thickness reduction. Discussion of these results has also supported the development of a more detailed understanding of the interaction of the process parameters and lead to a new theoretical and graphical representation of the ISF process.Many sheet forming processes such [sic] hammering and spinning, have been used in the manufacturing industry for decades and consequently have strengths and weakness that are well known. In contrast, Incremental Sheet Forming (ISF) is an emerging type of forming process whose capabilities are not yet fully understood. So while it is clear that ISF processes have several advantages, such as low cost and good surface finish [sic]. It has proved difficult to define the limits of the process in terms of macro-parameters such as deformation and sheet thickness. So whereas the capabilities of many sheet metal manufacturing processes are effectively characterized by forming limit curves this has not been possible with ISF. In other words, there is a lack of methodologies for assessing the feasibility of using ISF for particular components. This thesis investigates several aspects of the ISF process and develops a quantitative methodology that allows a first approximation of the feasibility of component manufacturing using the ISF process in terms of deflection and thickness reduction. It was found that thickness reduction can be accurately modeled in terms of analytical model developed for sheet metal forming. The predictions of the method are assessed and found to give a good correspondence with measured data for the range of wall angles, materials and geometries assessed. The parameters of the proposed methodology have been determined by experimental studies of commercially pure Titanium Grade 4 (CpTi), Aluminium alloys (AA1050-H-14, AA2024-O and AA7075-O) and Stainless Steel (SS304-L) to understand the process of incremental sheet forming and its impact on the final properties of the sheet metal. The proposed method called "ISF-FCheck" uses two charts to quantify maximum strain in relation to the depth and thickness reduction. Discussion of these results has also supported the development of a more detailed understanding of the interaction of the process parameters and lead to a new theoretical and graphical representation of the ISF process
New algorithms for ultrasonic non-destructive evaluation
Get PDFThe push for more efficient operation of power generation stations has led to the development of advanced alloys designed to cope with the stresses of running at elevated temperatures. The micro-structure of these new alloys makes the inspection process difficult due to large grains that scatter ultrasonic energy. Aerospace components such as aircraft engine turbine blades are made from similar materials and pose the same difficulties for inspection. In addition, the complex geometries of many of these parts hinder the use of existing advanced imaging methodologies. The current inspection process involves using both individual transducers and phased arrays to collect pulse-echo data from structures.This process is not sufficient for such difficult materials and a new process must be devised, tested and deployed. This thesis presents an investigation of new practical techniques to process ultrasonic array data collected via a Full Matrix Capture.Two novel signal processing techniques are presented, evaluated and compared to the Total Focusing Method, which is currently considered as the gold standard in ultrasonic array processing. A study into efficient imaging has also been completed, which involved development of an algorithm to focus upon any point through an arbitrary refracting interface. This algorithm was implemented on a commercially available graphics card and is able to account for a curved interface in real time with no prior knowledge of the surface profile.Spatially Averaged Sub-Aperture Correlation Imaging splits the full matrix of data into a set of sub-apertures which are imaged independently from each other. These images are then combined into two sets and are input to a two-dimensional cross-correlation algorithm that outputs a weighting matrix that can be applied to the sum of all images. Signals that are from legitimate reectors are highly correlated while less-correlated indications are the result of noise from scattering and multi-path propagation. SASACI has been shown to perform well experimentally through inspection of defects within multiple highly scattering welds at a frequency of 5 MHz.Correlation for Adaptively Focused Imaging aims to correct for anisotropy within difficult materials. The longitudinal velocity within a difficult material can vary with position and using an average velocity does not guarantee a well-focused image. For each pixel in an image,CAFI calculates which samples will be used to calculate the amplitude of the pixel before cross-correlating the signals from adjacent array elements and shifting the delay to the point of maximum focus. This methodology is effective when a small area with a known reflector is being imaged, and for this reason the algorithm is suited to characterisation of reflectors. This technique was experimentally validated on a block of Inconel 625 with a number of side-drilled holes.The push for more efficient operation of power generation stations has led to the development of advanced alloys designed to cope with the stresses of running at elevated temperatures. The micro-structure of these new alloys makes the inspection process difficult due to large grains that scatter ultrasonic energy. Aerospace components such as aircraft engine turbine blades are made from similar materials and pose the same difficulties for inspection. In addition, the complex geometries of many of these parts hinder the use of existing advanced imaging methodologies. The current inspection process involves using both individual transducers and phased arrays to collect pulse-echo data from structures.This process is not sufficient for such difficult materials and a new process must be devised, tested and deployed. This thesis presents an investigation of new practical techniques to process ultrasonic array data collected via a Full Matrix Capture.Two novel signal processing techniques are presented, evaluated and compared to the Total Focusing Method, which is currently considered as the gold standard in ultrasonic array processing. A study into efficient imaging has also been completed, which involved development of an algorithm to focus upon any point through an arbitrary refracting interface. This algorithm was implemented on a commercially available graphics card and is able to account for a curved interface in real time with no prior knowledge of the surface profile.Spatially Averaged Sub-Aperture Correlation Imaging splits the full matrix of data into a set of sub-apertures which are imaged independently from each other. These images are then combined into two sets and are input to a two-dimensional cross-correlation algorithm that outputs a weighting matrix that can be applied to the sum of all images. Signals that are from legitimate reectors are highly correlated while less-correlated indications are the result of noise from scattering and multi-path propagation. SASACI has been shown to perform well experimentally through inspection of defects within multiple highly scattering welds at a frequency of 5 MHz.Correlation for Adaptively Focused Imaging aims to correct for anisotropy within difficult materials. The longitudinal velocity within a difficult material can vary with position and using an average velocity does not guarantee a well-focused image. For each pixel in an image,CAFI calculates which samples will be used to calculate the amplitude of the pixel before cross-correlating the signals from adjacent array elements and shifting the delay to the point of maximum focus. This methodology is effective when a small area with a known reflector is being imaged, and for this reason the algorithm is suited to characterisation of reflectors. This technique was experimentally validated on a block of Inconel 625 with a number of side-drilled holes
Development of new catalytic processes for organic chemistry
No full textChapter 1 - Brønsted Acid-catalysed Enantioselective Conjugate Addition to Vinyl NHeterocycles This chapter details work towards the development of a new catalytic and enantioselective carbon-carbon and carbon-heteroatom bond forming method to enable access to desirable heterocyclic motifs containing functionalised stereocentres. Chiral Brønsted acid-catalysed conjugate addition to vinyl N-heterocycles was predicted to facilitate enantiocontrolled access to heterocycles containing a chiral benzylic and/or homobenzylic functionality (Scheme 1). Scheme 1. Brønsted acid-catalysed conjugate addition to substituted vinyl N-heterocycles [see thesis for details] From initial investigations, it became apparent that the most competent nucleophile was aniline which was selected as the nucleophile for optimisation studies. Vinyl pyridine systems displayed poor reactivity towards the conjugate addition, whereas a vinyl quinoline compound was found to be significantly more reactive and was chosen as a more competent Michael acceptor (Scheme 2).Scheme 2. Reactivity of vinyl quinoline system compared to vinyl pyridine system [see thesis for details] Optimisation of the process showed high selectivity could be achieved at the expense of conversion (33% conversion, 80% ee) and, conversely, high conversion could be achieved at the expense of selectivity (72% conversion, 64% ee). The rate of proton transfer in asymmetric protonations is an important factor in their success and controlling this will be key to developing the current methodology towards high selectivity at an appropriate degree of reactivity. Efforts to reconcile these have, so far, proved unsuccessful and work towards doing so will be undertaken within the group in the future.Chapter 2 - One-pot Formal Homologation of Boronic Acids: A Platform for Diversity-oriented Synthesis This chapter details methodology in which chemoselective formal homologation of boronic acids has been developed. Chemoselective Suzuki-Miyaura cross-coupling between a boronic acid and a haloaryl MIDA boronate (BMIDA) followed by controlled BMIDA hydrolysis reveals the formally homologated boronic acid product (Scheme 3). The chemoselectivity in this process arises from the selective cross-coupling of the haloarene with one boron species preferentially over the other. Scheme 3. Chemoselective formal homologation of boronic acids [see thesis for details] The process was immediately validated and efficiently optimised through the careful control of the reaction media (Scheme 4). Scheme 4. Validation and optimisation of homologation reaction [see thesis for details] Once optimised, the process was applied to a wide range of substrates which were successfully delivered in good to excellent yields (46-95%), a significant proportion of which are novel boronic acids (Scheme 5). Scheme 5. Scope of the developed boronic acid homologation reaction [see thesis for details] With the reaction scope firmly established, the next step would be to utilise the proven ability of the reaction to tolerate a range of substrates to synthesise a boronic acid which could act as a valuable precursor to a biologically relevant molecule. This boronic acid would then act as the platform for diversification in a display of the value of the methodology towards drug discovery programmes. Application of this procedure was successfully achieved in the synthesis of a range of bromodomain binding inhibitors (Scheme 6).Scheme 6. Application of the methodology towards diversity oriented synthesis [see thesis for details]Chapter 1 - Brønsted Acid-catalysed Enantioselective Conjugate Addition to Vinyl NHeterocycles This chapter details work towards the development of a new catalytic and enantioselective carbon-carbon and carbon-heteroatom bond forming method to enable access to desirable heterocyclic motifs containing functionalised stereocentres. Chiral Brønsted acid-catalysed conjugate addition to vinyl N-heterocycles was predicted to facilitate enantiocontrolled access to heterocycles containing a chiral benzylic and/or homobenzylic functionality (Scheme 1). Scheme 1. Brønsted acid-catalysed conjugate addition to substituted vinyl N-heterocycles [see thesis for details] From initial investigations, it became apparent that the most competent nucleophile was aniline which was selected as the nucleophile for optimisation studies. Vinyl pyridine systems displayed poor reactivity towards the conjugate addition, whereas a vinyl quinoline compound was found to be significantly more reactive and was chosen as a more competent Michael acceptor (Scheme 2).Scheme 2. Reactivity of vinyl quinoline system compared to vinyl pyridine system [see thesis for details] Optimisation of the process showed high selectivity could be achieved at the expense of conversion (33% conversion, 80% ee) and, conversely, high conversion could be achieved at the expense of selectivity (72% conversion, 64% ee). The rate of proton transfer in asymmetric protonations is an important factor in their success and controlling this will be key to developing the current methodology towards high selectivity at an appropriate degree of reactivity. Efforts to reconcile these have, so far, proved unsuccessful and work towards doing so will be undertaken within the group in the future.Chapter 2 - One-pot Formal Homologation of Boronic Acids: A Platform for Diversity-oriented Synthesis This chapter details methodology in which chemoselective formal homologation of boronic acids has been developed. Chemoselective Suzuki-Miyaura cross-coupling between a boronic acid and a haloaryl MIDA boronate (BMIDA) followed by controlled BMIDA hydrolysis reveals the formally homologated boronic acid product (Scheme 3). The chemoselectivity in this process arises from the selective cross-coupling of the haloarene with one boron species preferentially over the other. Scheme 3. Chemoselective formal homologation of boronic acids [see thesis for details] The process was immediately validated and efficiently optimised through the careful control of the reaction media (Scheme 4). Scheme 4. Validation and optimisation of homologation reaction [see thesis for details] Once optimised, the process was applied to a wide range of substrates which were successfully delivered in good to excellent yields (46-95%), a significant proportion of which are novel boronic acids (Scheme 5). Scheme 5. Scope of the developed boronic acid homologation reaction [see thesis for details] With the reaction scope firmly established, the next step would be to utilise the proven ability of the reaction to tolerate a range of substrates to synthesise a boronic acid which could act as a valuable precursor to a biologically relevant molecule. This boronic acid would then act as the platform for diversification in a display of the value of the methodology towards drug discovery programmes. Application of this procedure was successfully achieved in the synthesis of a range of bromodomain binding inhibitors (Scheme 6).Scheme 6. Application of the methodology towards diversity oriented synthesis [see thesis for details
Advances in tunable diode laser spectroscopy for aero engine research
Get PDFTunable diode laser spectroscopy (TDLS) is a widely used technique for the measurement of gas species and offers in-situ operation, accuracy and faster response time compared to other optical and non-optical gas sensing techniques.The work in this thesis focusses on the measurement of CO2 in the harsh environment of a gas turbine engine (GTE). The work is part of a much larger initiative called Fibre Laser Imaging of gas Turbine Exhaust Species (FLITES) aimed at obtaining concentration distributions of gas species such as CO2 and NO, unburnt hydrocarbons, and soot in a gas turbine exhaust plume using optical tomography. In the FLITES system, a thulium doped fibre amplifier (TDFA) is used to boost the optical power output from a 2 mW, 1997 nm, multi-quantum well distributed feedback (DFB-MQW) laser to feed 126 measurement channels arranged in dodecagon geometry for optical tomography. Hence, agile TDLS techniques need to be developed which can be scaled up to the multi-channel measurement system.Attributed by the interference from noise in the measurement environment of a GTE, phase sensitive detection using a lock-in amplifier (LIA) has to be employed where an additional current modulation is applied to the DFB laser, creating an instantaneous intensity modulated output and a delayed wavelength modulation (WM) output. This technique falls under a metrology branch known as wavelength modulation spectroscopy (WMS).The unknown measurement conditions expected in a GTE engine necessitates the use of calibration-free WMS techniques for the simultaneous measurement of gas concentration and temperature. Calibration-free techniques in WMS have been developed at the Centre for Microsystems and Photonics (CMP) of Strathclyde University. These are known as the phasor decomposition method (PDM) and the residual amplitude modulation (RAM) technique. They employ the signals obtained using the first harmonic demodulation of the WMS signals, followed by post processing to recover the gas absorption line shape. It was known in the CMP group that the accuracy of these techniques was limited by the variation in the laser modulation parameters such as the phase of the wavelength modulation relative to the intensity modulation (WM-IM phase lag) and the wavelength modulation amplitude across the laser current scan.The solutions to two problems are addressed in this thesis, viz. the implementation of correction procedures to account for the variation in the laser modulation parameters across the current scan and the need for a calibration-free technique for the measurement of CO2 in a GTE exhaust plume scalable to a multi-channel measurement system.Accurate measurements of the wavelength modulation parameters were made across the current scan and correction algorithms were implemented to compensate for its effects on the recovered gas absorption line shape.The gas spectral parameters were measured in the lab for the R48 absorption line of CO2 near 1997.2 nm at the higher temperatures (up to 500°C) expected in a GTE exhaust plume, using a heated gas cell. A Fourier expansion model was developed for the WMS signals which employ the measured laser modulation and gas spectral parameters. 1f normalised 2f WMS technique was chosen as the calibration-free measurement approach due to the advantages of cancellation of the transmission fluctuations as well as signal normalisation. The 2f/1f measurement technique was validated in the lab at higher temperatures for the simultaneous recovery of the CO2 concentration and temperature with an accuracy of 3.39 % and 3.72 %, respectively. Subsequently, field campaigns were conducted at the Rolls-Royce test facility at East Kilbride, yielding concentration and temperature values having good correlation to the engine operating conditions such as the throttle and core temperature.Multi-channel tomographic measurements were conducted on the test phantoms at INTA, Madrid, using TFLAS-WMS (tunable fibre laser absorption spectroscopy). Accurate concentration images could be recovered using tomographic reconstruction algorithms.Tunable diode laser spectroscopy (TDLS) is a widely used technique for the measurement of gas species and offers in-situ operation, accuracy and faster response time compared to other optical and non-optical gas sensing techniques.The work in this thesis focusses on the measurement of CO2 in the harsh environment of a gas turbine engine (GTE). The work is part of a much larger initiative called Fibre Laser Imaging of gas Turbine Exhaust Species (FLITES) aimed at obtaining concentration distributions of gas species such as CO2 and NO, unburnt hydrocarbons, and soot in a gas turbine exhaust plume using optical tomography. In the FLITES system, a thulium doped fibre amplifier (TDFA) is used to boost the optical power output from a 2 mW, 1997 nm, multi-quantum well distributed feedback (DFB-MQW) laser to feed 126 measurement channels arranged in dodecagon geometry for optical tomography. Hence, agile TDLS techniques need to be developed which can be scaled up to the multi-channel measurement system.Attributed by the interference from noise in the measurement environment of a GTE, phase sensitive detection using a lock-in amplifier (LIA) has to be employed where an additional current modulation is applied to the DFB laser, creating an instantaneous intensity modulated output and a delayed wavelength modulation (WM) output. This technique falls under a metrology branch known as wavelength modulation spectroscopy (WMS).The unknown measurement conditions expected in a GTE engine necessitates the use of calibration-free WMS techniques for the simultaneous measurement of gas concentration and temperature. Calibration-free techniques in WMS have been developed at the Centre for Microsystems and Photonics (CMP) of Strathclyde University. These are known as the phasor decomposition method (PDM) and the residual amplitude modulation (RAM) technique. They employ the signals obtained using the first harmonic demodulation of the WMS signals, followed by post processing to recover the gas absorption line shape. It was known in the CMP group that the accuracy of these techniques was limited by the variation in the laser modulation parameters such as the phase of the wavelength modulation relative to the intensity modulation (WM-IM phase lag) and the wavelength modulation amplitude across the laser current scan.The solutions to two problems are addressed in this thesis, viz. the implementation of correction procedures to account for the variation in the laser modulation parameters across the current scan and the need for a calibration-free technique for the measurement of CO2 in a GTE exhaust plume scalable to a multi-channel measurement system.Accurate measurements of the wavelength modulation parameters were made across the current scan and correction algorithms were implemented to compensate for its effects on the recovered gas absorption line shape.The gas spectral parameters were measured in the lab for the R48 absorption line of CO2 near 1997.2 nm at the higher temperatures (up to 500°C) expected in a GTE exhaust plume, using a heated gas cell. A Fourier expansion model was developed for the WMS signals which employ the measured laser modulation and gas spectral parameters. 1f normalised 2f WMS technique was chosen as the calibration-free measurement approach due to the advantages of cancellation of the transmission fluctuations as well as signal normalisation. The 2f/1f measurement technique was validated in the lab at higher temperatures for the simultaneous recovery of the CO2 concentration and temperature with an accuracy of 3.39 % and 3.72 %, respectively. Subsequently, field campaigns were conducted at the Rolls-Royce test facility at East Kilbride, yielding concentration and temperature values having good correlation to the engine operating conditions such as the throttle and core temperature.Multi-channel tomographic measurements were conducted on the test phantoms at INTA, Madrid, using TFLAS-WMS (tunable fibre laser absorption spectroscopy). Accurate concentration images could be recovered using tomographic reconstruction algorithms
Process analytical technology in tablet manufacturing
Get PDFProcess Analytical Technology (PAT) is the important tools to understand the process, obtaining critical process parameters and used as process monitoring following by quality by design (QbD) concept. It has been applied to the pharmaceutical manufacturing especially in every step of tablet production until final product in order to ensure the product quality. Otherwise, it would be an essential part of a scientific-based pharmaceutical quality assessment due to the food and drug administration announcement.The purpose of this research is to show the application of PAT tools through tablet manufacturing process; blending by cube mixer, granulation by twin-screw extruder and including finished product properties. Critical process parameters were identified through design of experiments (DoE), and then data of each step was recorded by widely accepted PAT approaches (e.g. near-infrared spectroscopy, particle size analysers) before initiation of downstream process to strengthen scientific data of design space. Moreover, multivariate analysis software (SIMCA), was involved in order to extract multivariate spectroscopic data to be comparable form such as Principal component analysis (PCA). This formulation contained two active pharmaceutical ingredients (API), Paracetamol and Caffeine, while others studies contain one which was challenging of this study. Nevertheless, this formulation based on high shear wet granulation method, however it was successful to be granulated with twin screw extruder. However, more studies with screw configuration are still required to improve shapes on granules.Blending uniformity was firstly studied by ATR-IR spectroscopy and PCA showed similarity of data after 10 min of blending in all 3 batches. Therefore, DoE was employed to optimize three critical process parameters; solid feeding rate, liquid feeding rate and extruder speed. EYECON and QICPIC were utilized for obtaining particle size distribution during experiments; consequently, one configuration which provided the best unimodular-shaped PSD was selected and full batch granulation was performed. Near Infrared spectroscopy (NIR) was equipped in order to monitor the product content uniformity along batch granulating. Spectrum were analysed to be Hotelling T² plot against time and used as process signature for the future batches and scale enlargement. Finally, after tablet compression, ingredient mapping on the tablet surface was illustrated by Raman Microscope to ensure the uniformity of 2 active pharmaceutical ingredients on the tablet. Maps showed uniformly spreading of each API on the table surface.This studies were demonstrated that PAT tools can be involved along the process development, obtain data of attributes and be a part of decision tools. It could be a sample for involvement of PAT tools in the whole manufacturing process and could be further applied for an industrial production which corresponded to QbD concept to make better strategy for drug quality assurance for the next recent years.Process Analytical Technology (PAT) is the important tools to understand the process, obtaining critical process parameters and used as process monitoring following by quality by design (QbD) concept. It has been applied to the pharmaceutical manufacturing especially in every step of tablet production until final product in order to ensure the product quality. Otherwise, it would be an essential part of a scientific-based pharmaceutical quality assessment due to the food and drug administration announcement.The purpose of this research is to show the application of PAT tools through tablet manufacturing process; blending by cube mixer, granulation by twin-screw extruder and including finished product properties. Critical process parameters were identified through design of experiments (DoE), and then data of each step was recorded by widely accepted PAT approaches (e.g. near-infrared spectroscopy, particle size analysers) before initiation of downstream process to strengthen scientific data of design space. Moreover, multivariate analysis software (SIMCA), was involved in order to extract multivariate spectroscopic data to be comparable form such as Principal component analysis (PCA). This formulation contained two active pharmaceutical ingredients (API), Paracetamol and Caffeine, while others studies contain one which was challenging of this study. Nevertheless, this formulation based on high shear wet granulation method, however it was successful to be granulated with twin screw extruder. However, more studies with screw configuration are still required to improve shapes on granules.Blending uniformity was firstly studied by ATR-IR spectroscopy and PCA showed similarity of data after 10 min of blending in all 3 batches. Therefore, DoE was employed to optimize three critical process parameters; solid feeding rate, liquid feeding rate and extruder speed. EYECON and QICPIC were utilized for obtaining particle size distribution during experiments; consequently, one configuration which provided the best unimodular-shaped PSD was selected and full batch granulation was performed. Near Infrared spectroscopy (NIR) was equipped in order to monitor the product content uniformity along batch granulating. Spectrum were analysed to be Hotelling T² plot against time and used as process signature for the future batches and scale enlargement. Finally, after tablet compression, ingredient mapping on the tablet surface was illustrated by Raman Microscope to ensure the uniformity of 2 active pharmaceutical ingredients on the tablet. Maps showed uniformly spreading of each API on the table surface.This studies were demonstrated that PAT tools can be involved along the process development, obtain data of attributes and be a part of decision tools. It could be a sample for involvement of PAT tools in the whole manufacturing process and could be further applied for an industrial production which corresponded to QbD concept to make better strategy for drug quality assurance for the next recent years
Exploring leaders' strategies for managing negative emotions of sales people
Get PDFThe aim of this thesis is to explore the practice of leader strategies to manage and influence employees' emotions and its implications. Emotion has emerged as a key field in organisational behaviour, particularly pertaining to leadership. Managing followers' emotions is critical for leaders since employees' emotions are directly related to job performance. Most studies focus on measuring the high level relationship between the constructs of emotions and leadership and there is little research on how leaders deliberately manage the emotions of their followers.This qualitative study explores sales leaders' practices for managing followers' negative emotions through a case study method using semi-structured interviews and critical incident technique. 32 sales leaders are interviewed from one of the top logistics companies; 89 critical incidents are identified where these leaders were challenged with managing their followers' emotions.The findings of this research show that leaders consider changing employees' negative emotions a key function of leadership. The critical incidents demonstrate that leaders face both business and personal problems. Dealing with business situations requires strategies that involve more changing the problem or its meaning, while personal situations require strategies for reducing the intensity of the emotions.The findings also demonstrate that the existing models of emotion regulation do not cover all of the strategies that leaders use to effectively manage followers' emotions. Therefore, a proposed comprehensive set of strategies that leaders can use is presented together with contextual factors that leaders should consider when managing followers' negative emotions, including the use of short-intermediate strategies and person focused strategies.This study is among the first to qualitatively explore how leaders actually manage followers' negative emotions. A recommended set of strategies is presented to help leaders regulate and deal with negative or dysfunctional emotions. The findings provide clarification on what strategies leaders can use and how this practice can be improved.The aim of this thesis is to explore the practice of leader strategies to manage and influence employees' emotions and its implications. Emotion has emerged as a key field in organisational behaviour, particularly pertaining to leadership. Managing followers' emotions is critical for leaders since employees' emotions are directly related to job performance. Most studies focus on measuring the high level relationship between the constructs of emotions and leadership and there is little research on how leaders deliberately manage the emotions of their followers.This qualitative study explores sales leaders' practices for managing followers' negative emotions through a case study method using semi-structured interviews and critical incident technique. 32 sales leaders are interviewed from one of the top logistics companies; 89 critical incidents are identified where these leaders were challenged with managing their followers' emotions.The findings of this research show that leaders consider changing employees' negative emotions a key function of leadership. The critical incidents demonstrate that leaders face both business and personal problems. Dealing with business situations requires strategies that involve more changing the problem or its meaning, while personal situations require strategies for reducing the intensity of the emotions.The findings also demonstrate that the existing models of emotion regulation do not cover all of the strategies that leaders use to effectively manage followers' emotions. Therefore, a proposed comprehensive set of strategies that leaders can use is presented together with contextual factors that leaders should consider when managing followers' negative emotions, including the use of short-intermediate strategies and person focused strategies.This study is among the first to qualitatively explore how leaders actually manage followers' negative emotions. A recommended set of strategies is presented to help leaders regulate and deal with negative or dysfunctional emotions. The findings provide clarification on what strategies leaders can use and how this practice can be improved
Chip-scale atomic magnetometer
Get PDFThis thesis was previously held under moratorium from 1st December 2016 until 1st June 2020This thesis describes the physics and technology adopted to implement a Bell-Bloom type atomic magnetometer at Strathclyde University. We show that the device is a functional experimental prototype, useful as the primary reference for future chip-scale miniaturization. The sensor head and core of the device is a small (approximatively 20 mm3) cubic cell derived from a silicon wafer structure and filled with a caesium azide (CsN3) compound. When the wafer is exposed to UV light, the azide is dissociated in its components; in this way the cells are filled with caesium atoms in the vapour form, which constitute the magnetically sensitive elements of the device, and nitrogen gas, used to optimize the performances of the sensor head. We are able to characterize a whole wafer in a relatively short period of time, in terms of caesium vapour and nitrogen gas pressures, and for this purpose, we developed a data analysis tool based on caesium spectroscopy. In the Bell-Bloom scheme the magnetic resonance is not excited by RF coils but by optical modulation of the input laser light: the laser could be modulated in frequency, amplitude (i.e. intensity) or polarization but we adopted the amplitude modulation scheme because it requires the use of only one beam and an overall simpler set-up; it also allows the possibility of directly detecting Larmor oscillations. In the basic experimental set-up, a light beam from a diode laser, tuned to the D1 line of the caesium spectrum, is elliptically polarized and amplitude modulated; the light is then focused in and out the cell, through its opposite glass apertures, and the transmitted light is detected. The sensor head is enclosed inside a magnetic shield where the desired (lownoise and spatially uniform) magnetic field is generated by two orthogonal pairs of Helmholtz coils. The cell is heated to reach the desired caesium vapour density with a non-magnetic resistor: its current is switched on and off and the signal is detected only during the off part to avoid undesired magnetic noise. The laser intensity is cycled from a short and intense impulse, called "pump", to a longer and weaker beam, named "probe". The first is used to align the spins of the caesium atoms, so that the macroscopic magnetization precess around the magnetic field, while the second detects this so-called Larmor precession. The two orthogonal polarization components of this oscillation are found to be almost out of phase which justifies the use of a polarimeter to separately analyse their properties and investigate the possibility of signal subtraction to improve the signal-to-noise ratio. In order to describe and optimize the experiment, the main experimental parameters (polarization, pump and probe intensities, sensor head temperature, laser frequency, magnetic field intensity and direction) have been analysed extensively in their effect on the oscillating signals. We observed that the Larmor oscillations are damped and a pseudo magnetic field is generated by the laser, and that both are proportional to the probe intensity. This research also presents a model that successfully explains the main experimental observations and extends the common representation in current literature by further predicting the best laser frequency and input polarization and the out of phase phenomena previously described. The model uses the multi-pole expansion of the density matrix, truncated to its first order, and gives a satisfactory vectorial representation of the relationships between the main experimental parameters. Finally, we have reached a complete noise characterization of the apparatus in the frequency domain. A data analysis tool is able to fully describe the performances of the magnetometer in terms of its sensitivity relatively quickly. A sensitivity lower then 5 pT/ p Hz at 850 Hz has been achieved which, if reproduced on a miniaturised level, will allow the device to compete with the current chip-scale atomic magnetometers.This thesis describes the physics and technology adopted to implement a Bell-Bloom type atomic magnetometer at Strathclyde University. We show that the device is a functional experimental prototype, useful as the primary reference for future chip-scale miniaturization. The sensor head and core of the device is a small (approximatively 20 mm3) cubic cell derived from a silicon wafer structure and filled with a caesium azide (CsN3) compound. When the wafer is exposed to UV light, the azide is dissociated in its components; in this way the cells are filled with caesium atoms in the vapour form, which constitute the magnetically sensitive elements of the device, and nitrogen gas, used to optimize the performances of the sensor head. We are able to characterize a whole wafer in a relatively short period of time, in terms of caesium vapour and nitrogen gas pressures, and for this purpose, we developed a data analysis tool based on caesium spectroscopy. In the Bell-Bloom scheme the magnetic resonance is not excited by RF coils but by optical modulation of the input laser light: the laser could be modulated in frequency, amplitude (i.e. intensity) or polarization but we adopted the amplitude modulation scheme because it requires the use of only one beam and an overall simpler set-up; it also allows the possibility of directly detecting Larmor oscillations. In the basic experimental set-up, a light beam from a diode laser, tuned to the D1 line of the caesium spectrum, is elliptically polarized and amplitude modulated; the light is then focused in and out the cell, through its opposite glass apertures, and the transmitted light is detected. The sensor head is enclosed inside a magnetic shield where the desired (lownoise and spatially uniform) magnetic field is generated by two orthogonal pairs of Helmholtz coils. The cell is heated to reach the desired caesium vapour density with a non-magnetic resistor: its current is switched on and off and the signal is detected only during the off part to avoid undesired magnetic noise. The laser intensity is cycled from a short and intense impulse, called "pump", to a longer and weaker beam, named "probe". The first is used to align the spins of the caesium atoms, so that the macroscopic magnetization precess around the magnetic field, while the second detects this so-called Larmor precession. The two orthogonal polarization components of this oscillation are found to be almost out of phase which justifies the use of a polarimeter to separately analyse their properties and investigate the possibility of signal subtraction to improve the signal-to-noise ratio. In order to describe and optimize the experiment, the main experimental parameters (polarization, pump and probe intensities, sensor head temperature, laser frequency, magnetic field intensity and direction) have been analysed extensively in their effect on the oscillating signals. We observed that the Larmor oscillations are damped and a pseudo magnetic field is generated by the laser, and that both are proportional to the probe intensity. This research also presents a model that successfully explains the main experimental observations and extends the common representation in current literature by further predicting the best laser frequency and input polarization and the out of phase phenomena previously described. The model uses the multi-pole expansion of the density matrix, truncated to its first order, and gives a satisfactory vectorial representation of the relationships between the main experimental parameters. Finally, we have reached a complete noise characterization of the apparatus in the frequency domain. A data analysis tool is able to fully describe the performances of the magnetometer in terms of its sensitivity relatively quickly. A sensitivity lower then 5 pT/ p Hz at 850 Hz has been achieved which, if reproduced on a miniaturised level, will allow the device to compete with the current chip-scale atomic magnetometers
Assessment of coronal mechanical alignment with applied varus and valgus force through the range of flexion using non-invasive navigation
Get PDFOsteoarthritis of the knee is a highly prevalent disease, with total knee arthroplasty (TKA) a proven means of alleviating symptoms. In image-free navigation, infra-red markers are attached to bony landmarks to provide kinematic data during the TKA procedure, with the aim of improving the precision of the implant placement. In non-invasive navigation, infra-red markers are attached to the skin surface; recent evidence suggests that this can give reliable measurements of lower limb mechanical alignment. The aim of this thesis was to evaluate the use of a non-invasive navigation system in the assessment of mechanical alignment with applied coronal force through the range of flexion. A previously validated non-invasive system (Physiopilot) was tested on 23 volunteers with healthy knees. 2 users performed 2 registrations of the software workflow on each participant's right and left knees. A force was manually applied to the end-point of varus and valgus knee laxity and the measured change in mechanical alignment was recorded. Force was applied with the knee positioned in increments of flexion from 0˚-90˚. In keeping with previous studies, satisfactory values of CR (Coefficient of Repeatability) of 1.55 and 1.33 were found for intra-observer repeatability in measurement of supine Mechanical Femoro-tibial Angle (MFTA) in extension, with a good inter-observer correlation of ICC (intraclass Correlation Coefficient) 0.72. However, when flexion was introduced, intra-observer and inter-observer reliability fell outwith acceptable limits. The trial therefore did not support the Physiopilot system as a measure of MFTA when flexion is introduced. It was felt that learning-curve, soft tissue artefacts and lack of force standardisation equipment may have accounted for significant levels of error, with further studies required to address these issues.Osteoarthritis of the knee is a highly prevalent disease, with total knee arthroplasty (TKA) a proven means of alleviating symptoms. In image-free navigation, infra-red markers are attached to bony landmarks to provide kinematic data during the TKA procedure, with the aim of improving the precision of the implant placement. In non-invasive navigation, infra-red markers are attached to the skin surface; recent evidence suggests that this can give reliable measurements of lower limb mechanical alignment. The aim of this thesis was to evaluate the use of a non-invasive navigation system in the assessment of mechanical alignment with applied coronal force through the range of flexion. A previously validated non-invasive system (Physiopilot) was tested on 23 volunteers with healthy knees. 2 users performed 2 registrations of the software workflow on each participant's right and left knees. A force was manually applied to the end-point of varus and valgus knee laxity and the measured change in mechanical alignment was recorded. Force was applied with the knee positioned in increments of flexion from 0˚-90˚. In keeping with previous studies, satisfactory values of CR (Coefficient of Repeatability) of 1.55 and 1.33 were found for intra-observer repeatability in measurement of supine Mechanical Femoro-tibial Angle (MFTA) in extension, with a good inter-observer correlation of ICC (intraclass Correlation Coefficient) 0.72. However, when flexion was introduced, intra-observer and inter-observer reliability fell outwith acceptable limits. The trial therefore did not support the Physiopilot system as a measure of MFTA when flexion is introduced. It was felt that learning-curve, soft tissue artefacts and lack of force standardisation equipment may have accounted for significant levels of error, with further studies required to address these issues
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