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Duplex functionally graded and multilayered thermal barrier coatings based on 8 % yttria stabilized zirconia and pyrochlores
Thermal Barrier Coatings (TBCs) protect gas turbine engine metal components while they serve in a high temperature environment (upto 1200?). 8% Yttria- Stabilized Zirconia (8YSZ) is the current state of the art material for TBCs. Typically, 250 to 500 ?m (upto 2 mm) thick TBCs can lower the metal temperature by upto 150C than the service temperature and thereby enhance life to the components. 8YSZ TBCs however, suffer from (a) increased sinterability, (b) phase de-stabilization and (c) poor adhesion with time in service at high temperature. In order to facilitate longer engine running time, research is being directed towards finding (i) newer materials that do not possess these deficiencies or (ii) configurations that can overcome them. In order to further improve the performance efficiency of the engines, TBC materials with extended thermal fatigue life at higher than current service temperatures (>1100?) are also being actively investigated. In the same area of research, this thesis presents the findings of work on air plasma sprayed (i) duplex, (ii) functionally graded and (iii) multilayered configurations of TBCs synthesized from commercial 8YSZ and lab synthesized pyrochlore (lanthanum zirconate, lanthanum cerate and lanthanum cerium zirconate) compositions with NiCrAlY bond coat. Duplex i.e., 2-layered TBCs, synthesized by depositing commercial 8YSZ ceramic topcoat (METCO 204 NS) and NiCrAlY bond coat (AMDRY 962) plasma spray powders on Inconel 718 and/or stainless-steel substrates were used for benchmarking purpose (designated as conventional 8YSZ TBC). Next, TBCs were prepared by using these two powders in blended form (8YSZ+NiCrAlY) to serve as a third intermediate layer between the duplex TBC layers in functionally graded material (FGM) configurations. The role of he third intermediate layer is to minimize the thermal expansion mismatch between the ceramic and bond coat layers at elevated temperatures. 8YSZ FGM TBCs were prepared from three different blends of plasma spray powders of NiCrAlY and 8YSZ (i .e., 25%NiCrAlY +75%8YSZ, 50% NiCrAlY + 50% 8YSZ and 60% NiCrAlY + 40% 8YSZ). The development of newer ceramic TBC materials and configurations was achieved by the synthesis of novel pyrochlores and FGM TBCs from them. The Rare-earth pyrochlores and Rare-earth zirconate pyrochlores studied were (i) Lanthanum Zirconate (La2Zr2O7), (ii) Lanthanum Cerium Zirconate (La2 (Zr0.7Ce0.3)2O7 and (iii) Lanthanum Cerate (La2Ce2O7). Plasma sprayable powders of these compositions were synthesized in the laboratory via a solid-state method. They were spray-coated by Atmospheric Plasma Spray (APS) method in duplex layers by using three different spray parameters on NiCrAlY bond coated substrates. The spray parameter that provided the best TBC for each composition was identified based on preliminary thermal fatigue tests. FGM TBCs with (50% NiCrAlY+ 50% 8YSZ) blend as intermediary layer exhibited significantly improved thermal fatigue resistance (life) over conventional 8YSZ TBC (up to 1400?). Hence, in the FGM pyrochlore system too, further studies were restricted to TBCs with (50%NiCrAlY+50% pyrochlore) blend layers to serve as the intermediate FGM layers. Further studies involved the synthesis of multilayered TBCs: two types of systems have been experimented (a) FGM with commercial 8YSZ integrated with the pyrochlores - here the intermediary blend layer was (50% NiCrAlY+ 50% 8YSZ), and lab synthesized pyrochlores were the topcoats and (b) 8YSZ as an intermediary layer and pyrochlores as the topcoats. Identical (to the extent possible) characterization methods were employed to study and evaluate all TBCs synthesized in this research work. They were (1) thermal fatigue tests between high temperature & ambient by using (a) gas flame (1200? & 1400?) and (b) furnace (1150C) (2) oxidation stability tests (at 800?,1000? and 1150?) (3) structural phase analysis (XRD) and (4) microstructure with chemical composition analysis (SEM/EDS). The work was aided by studies on adhesion strength test (ASTM C633 standard), residual stress analysis and assessment of thermal barrier effect (temperature drop across TBC) in chosen few TBCs. TBCs fabricated from three pyrochlores exhibited significant improvements in terms of thermal fatigue resistance at 1200? and 1400?. In duplex, Multilayer (ML) FGM and Multilayer (ML) configurations, La2Ce2O7 (LC) TBC performance was exemplary in all configurations studied in this research work. XRD analysis of pyrochlores in duplex, ML-FGM and ML configurations TBCs evaluated for thermal fatigue at 1200? and 1400? (gas flame heating) exhibited no phase destabilization in the failed specimen, confirming the thermal stability of the TBC system within the coated layers. The trend of improved thermal fatigue resistance of lanthanum cerate TBCs continued when studied via high-temperature furnace heating at 1150? as well. The experimental research work with details of TBC systems, processing, characterizations, and discussion based on findings and published literature to explore the prospective TBC material system and configuration with the potential to serve as an alternative to conventional 8YSZ TBC, in terms of life and thermal fatigue resistance, comprise the main contents of this thesis. -
Duplex functionally graded and multilayered thermal barrier coatings based on 8% yttria stabilized zirconia and pyrochlores
Thermal Barrier Coatings (TBCs) protect gas turbine engine metal components while they serve in a high temperature environment (upto 1200℃). 8% YttriaStabilized Zirconia (8YSZ) is the current state of the art material for TBCs. Typically, 250 to 500 μm (upto 2 mm) thick TBCs can lower the metal temperature by upto 150°C than the service temperature and thereby enhance life to the components. 8YSZ TBCs however, suffer from (a) increased sinterability, (b) phase de-stabilization and (c) poor adhesion with time in service at high temperature. In order to facilitate longer engine running time, research is being directed towards finding (i) newer materials that do not possess these deficiencies or (ii) configurations that can overcome them. In order to further improve the performance efficiency of the engines, TBC materials with extended thermal fatigue life at higher than current service temperatures (>1100℃) are also being actively investigated. In the same area of research, this thesis presents the findings of work on air plasma sprayed (i) duplex, (ii) functionally graded and (iii) multilayered configurations of TBCs synthesized from commercial 8YSZ and lab synthesized pyrochlore (lanthanum zirconate, lanthanum cerate and lanthanum cerium zirconate) compositions with NiCrAlY bond coat.
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Dynamic Offloading Technique for Latency Sensitive Iot Applications Using Fog Computing
The Internet of Things (IoT) has evolved as one of the most popular technological newlineinnovations that offers processing power to different types of entities connected to it. IoT has made traditional applications smarter and easier to use. IoT offers reliable service to different sectors such as healthcare, industrial control, agriculture, autonomous vehicles, traffic management etc. IoT nodes are generally energy-constrained and hence depend on cloud platforms for storage and analytics of generated data. The cloud provides required services for the newlineconnected applications based on pay per use policy. But cloud datacenter being at remote location fails to accommodate the time requirements of delay-sensitive IoT newlineapplications. Edge/fog computing was designed to address the demands of timesensitive IoT applications. The IoT-Fog-Cloud architecture reduces the delay and response time incurred by the IoT-Cloud model. The fog layer in the three-tier architecture is distributed in nature. Hence the latency depends on how well the underlying offloading algorithms distribute the tasks among available fog nodes. Different offloading policies are mentioned in the literature to address this issue. This work initially tries to solve the offloading problem using one of the novel newlineoffloading approaches Flamingo Search Algorithm (FSA). Later, the results obtained from FSA are fine-tuned using another metaheuristic algorithm, the Honey Badger Algorithm (HBA). Finally, both FSA and HBA are hybridized to generate the HB-FS algorithm which effectively solves the task offloading problem. The performance evaluation of the proposed approach is done with different existing metaheuristic algorithms and the evaluations show that the newlineproposed work outperforms the existing algorithms in terms of latency, average newlineresponse time and execution time. The methodology also offers a lesser degree of newlineimbalance and standard deviation than the compared approaches. -
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Dynamics of Newtonian Fluids and Nanofluids in Various Geometries
In this thesis, the boundary-layer flows of Newtonian fluids in different geometries newlineprimarily, a horizontal surface and a vertical surface. To account for the imperfections arising in realistic scenarios, we have considered a horizontal surface with undulations and a vertical surface with a non-uniform temperature distribution. Additionally, it is wellknown that to meet the cooling rate requirements in the industry, the thermal performance of ordinary heat transfer fluids is not suitable. The concept of insertion of nanometresized metallic particles in the fluid leads to an increase in the thermal conductivity of the newlineordinary base liquids. Therefore, to fully comprehend the affect of these nanoparticles on the onset of convection and fluid motions and to assess how the enhanced thermophysical newlineproperties may affect the heat transfer is another key objective of this research. newlineA Comparative Study of Thermo-convective Flows of a Newtonian Fluid over Three newlineHorizontal Undulated Surfaces in a Porous Medium In the first problem of this thesis, elaborated in Chapter 5, a comparison has been presented between the results of three thermoconvective flows of a Newtonian fluid over uniformly heated, undulated horizontal surfaces in a porous medium against the background of the results of a flat plate. The undulations are assumed to have sinusoidal, sawtooth, and triangular waveforms. At large surface amplitudes, secondary flow is observed in the cases newlineof sinusoidal and triangular waveforms, but not in the cases of a sawtooth surface and a newlineflat plate. The variation of the mean Nusselt number and mean skin friction with surface newlineamplitude and the Rayleigh number indicate that heat transfer and viscous friction at the boundary increase with individual and collective increases in the values of the amplitude and the Rayleigh number. The heat transfer and skin friction by the flat surface are much less than that of all three undulated surfaces. -
East West Interface In 20Th Century India: Analysis Of Western Women???S Responses
In the twenty-first century, the Western world is seeking a greater understanding of the people and nations of Asia, India in particular. The thesis, ???East West Interface in 20th century India: Analysis of Western women???s responses??? is an attempt to illuminate at least an aspect of that interface during a given period of the past, so as to help shed some light on the present day Western approach to India. Throughout the colonial period, Western women got attracted to India. However, during the 20th century, arrival of four eminent Western women from diverse backgrounds, with different intentions had far-reaching impact for India. Katherine Mayo, Margaret Elizabeth Noble, Annie Besant and Madeline Slade, not only got actively involved with the Indian society but in their own ways contributed towards transforming the Indian society. They left an overwhelming impact on the Indian political fabric. The thesis aims to analyze the contribution of these four outstanding Western women and attempts to understand how Indian socio-political and cultural structure got influenced by and drew inspirations from them. This work also attempts to add to the process of evolution of understanding the East by the West. -
East west interfaces in 20th century india:
In the twenty-first century, the Western world is seeking a greater understanding of the people and nations of Asia, India in particular. The thesis, East West Interface in 20th century India: Analysis of Western women s responses is an attempt to illuminate at least an aspect of that interface during a given period of the past, so as to help shed some light on the newlinepresent day Western approach to India. Throughout the colonial period, Western women got attracted to India. However, during the 20th century, arrival of four eminent Western women from diverse backgrounds, with different intentions had far-reaching impact for India. Katherine Mayo, Margaret Elizabeth Noble, Annie Besant and Madeline Slade, not only got actively involved with the Indian society but in their own ways contributed towards newlinetransforming the Indian society. newlineThey left an overwhelming impact on the Indian political fabric. The thesis aims to analyze the contribution of these four outstanding Western women and attempts to understand how Indian socio-political and cultural structure got influenced by and drew inspirations from them. This work also attempts to add to the process of evolution newlineof understanding the East by the West. newline -
Echo mapping of active galactic nuclei
Active galactic nuclei (AGN) are the persistent high luminosity sources powered by accretion of matter onto super massive black holes (SMBHs) at their centres. They are known to show flux variation and this property can be used as an effective tool to map the extent of the broad line region (BLR) and the dusty torus that surrounds the central SMBH. Though the mass of the SMBH (MBH) can be directly measured using the dynamics
of stars that are close to the SMBH, this method is limited to objects in the low redshift Universe (z < 0.1). On the other hand, the technique of reverberation mapping (RM) can provide MBH estimate over a range of redshifts. RM is based on the light travel time delayed response of the line emitting gas as well as the re-processed torus emission to changes in the continuum emission from the accretion disk. As of now, MBH measurements are available for more than 100 sources based on RM. The obtained
BLR sizes (RBLR) are found to be correlated with the optical luminosity (L5100) at wavelength 5100 Å. This relationship is obtained based on measurements of AGN available over a limited range of luminosity. Moreover, many of these measurements also have larger error bars. Therefore, there
is an urgent need to increase RM measurements with small errors on more AGN covering a wide range of redshifts to better constrain the RBLR − L5100 relation. -
Echo mapping of active galacticn nuclei
Active galactic nuclei (AGN) are the persistent high luminosity sources powered by accretion of matter onto super massive black holes (SMBHs) at their centres. They are known to show flux variation and this property can be used as an effective tool to map the extent of the broad line region (BLR) and the dusty torus that surrounds the central SMBH. Though the mass of the SMBH (MBH) can be directly measured using the dynamics of stars that are close to the SMBH, this method is limited to objects in the low redshift Universe (z < 0.1). On the other hand, the technique of reverberation mapping (RM) can provide MBH estimate over a range of redshifts. RM is based on the light travel time delayed response of the line emitting gas as well as the re-processed torus emission to changes in the continuum emission from the accretion disk. As of now, MBH measure-ments are available for more than 100 sources based on RM. The obtained BLR sizes (RBLR) are found to be correlated with the optical luminosity (L5100) at wavelength 5100 This relationship is obtained based on mea-surements of AGN available over a limited range of luminosity. Moreover, many of these measurements also have larger error bars. Therefore, there is an urgent need to increase RM measurements with small errors on more AGN covering a wide range of redshifts to better constrain the RBLR ? L5100 relation. We have carried out photometric reverberation observa- tions on the AGN Mrk 590. Using both broad band (that overlaps with the continuum) and narrow band (that overlaps with the H? emission line) observations, we found the BLR size to be 21.44+1.49 ?2.11 days, which is equiv- alent to 0.018+0.001 ?0.002 pc. Using this measured BLR size and the full width at half maximum of the H? line measured from the newly acquired Subaru spectrum we found a black hole mass of 1.96+0.15 ?0.21 108 M , using virial relationship and adopting a scale factor of 1.12. Similar to BLR reverberation mapping, the extent of the dusty torus in AGN can also be measured using dust reverberation mapping (DRM) based on the delayed response of the near infrared (NIR) flux from the torus to the ionizing UV/optical continuum coming from the accretion disk. From these observations too, a strong correlation is known to exist between the torus size (Rdust) and the optical luminosity (LV). Based on the Rdust ?LV relation, it is also possible to use AGN as standard candle to con- strain the Hubble constant (H0) and other cosmological parameters. But for that, a large number of DRM observations are needed at different red- shifts. As of today, very few NIR interferometric observations are avail-able, but measurements of the torus size via such direct imaging observa-tions are again limited to very near and bright AGN. Moreover, there is a large discrepancy in the size of the torus obtained via the direct imaging method through interferometry and that obtained from DRM. From long term monitoring in the optical and infra-red, we found the inner edge of the dust torus in H0507+164 and Z229?15 to lie at a distance of 0.029+0.010 ?0.008 pc and 0.017+0.005 ?0.005 pc, respectively, from the central optical continuum source. These two new measurements are also found to lie closely on the known Rdust ? LV relation line. Also, by modeling the available BLR RM data in the literature, it is possible to constrain the size, structure and kinemat-ics of the BLR using Bayesian approach. This approach is adopted several times to study the BLR morphology by different ways but is not applied to a large number of sources in an homogeneous manner. From an analysis of the RM data for a total of 57 sources following a Bayesian approach, we could constrain the structure of the BLR in them as well as derive other properties of BLR. -
Economic Burden and Productivity Loss of Employees with Lifestyle Diseases in Sedentary Occupations During Pandemic
Over the past few decades, the prevalence of Lifestyle Diseases or Non-Communicable Diseases (NCDs) have increased. There has been an increasing concern about these lifestyle diseases, with hypertension acting as the most prevalent lifestyle disease in the populace. It further exaggerates the issue as its prevalence increases exposure to other lifestyle diseases such as Diabetes and Cardiovascular Diseases (CVD). With health being an important component of human capital, the presence of lifestyle diseases has an economic impact on the individual and the organisation. The presence of an illness reduces the productivity level delivered by the individual to work, resulting in productivity loss. Apart from impacting an employee's productivity, the prevalence of lifestyle diseases incurs a significant monetary expense in the form of healthcare required to manage them. This monetary expense is called an economic burden or out-of-pocket expenditure. On these grounds, the current study examines the economic burden and impact on the productivity of employees suffering from lifestyle diseases (Hypertension, Diabetes and CVD) working in sedentary occupations. With lifestyle diseases majorly influenced by the lifestyle patterns of an individual, employees working in a sedentary occupation are at greater exposure to lifestyle diseases and hence were selected as the target population. A cross-sectional study was conducted among 426 employees of sedentary occupations in the Delhi-NCR region. The economic burden has been measured as a sum of the direct and indirect costs of the diseases incurred in a year. Using the estimates of economic burden, Catastrophic Healthcare Expenditure (CHE) was measured at different threshold levels. The study has also evaluated productivity loss through presenteeism and absenteeism approaches. An attempt was made to examine the relationship between the economic burden 7 and productivity loss through presenteeism and absenteeism approaches. The result of the study shows a significant share of the economic burden for lifestyle diseases and their comorbidities. CHE was highest at the 40% threshold level. The level of disparity in catastrophe among lower and high-income individuals was also highest at the 40% threshold level. Further statistical results show a high cost of absenteeism due to lifestyle diseases compared to presenteeism and found that economic burden has a strong positive relationship with absenteeism and presenteeism. Overall, the study concludes that lifestyle disease incurs a substantial economic burden and CHE for employees working in sedentary occupations. The estimate for the same increases if multiple lifestyle diseases are present. Further, the impact of catastrophe is more for low-income than high-income individuals due to the limited availability of resources to manage the health issue. Apart from causing monetary expense, the presence of lifestyle diseases also causes a high cost of absenteeism and presenteeism, increasing the economic cost of managing lifestyle diseases. -
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EDUCATION AND SKILL REQUIREMENTS: A STUDY OF INFORMATION TECHNOLOGY INDUSTRY IN BANGALORE
India is passing through the crucial phase of demographic transition wherein a majority of its population is in the working age, giving India a never before opportunity to cash in on a huge demographic dividend. This brings spotlight on the human capital benefits that can accrue as a result of this phase with 54% of Indias 1.2 billion population under the age of 25. It is highly imperative for India to cash in on this critical phase through the creation and capitalization of knowledge, competency and the skill base of its people or the Human Capital and pave the way for faster economic growth and development of its economy. The study takes in to consideration the Information Technology industry, wherein Indias prowess has been widely celebrated with Indian software engineers doing exceedingly well and there has been an apparent unstoppable outflow of jobs to India from U.S and Europe. India has become the undisputed global hub for outsourcing and technology mediated work. This has been possible primarily because of the rich pool of technically proficient English speaking workforce with superior logical and reasoning skills. One of the prime reasons for this has been the vast network of academic infrastructure in India churning out more than 500,000 technical graduates annually (NASSCOM, 2012). But multiple surveys by NASSCOM and CII have shown severe gap between employment and employability of technical graduates with only 25% of technical graduates suitable for employment, the rest lacking in skills which the industry wants. In order to solve this paradox, the study was initiated to examine the skill requirements of new recruits in the IT sector. It aims at bringing about the differences, if any between the perception of academia and the industry on the importance of specific skill sets for new IT recruits. The study also explores if there is any disconnect between what the industry perceives to be the available skill sets among the new IT recruits and what the academia perceives to have imparted in terms of those skill sets to their students. In order to capture the perception of the academia and the industry, the study takes in to account their responses on a five-point likert scale on the desired level and actual level of proficiency of new IT recruits on technical, business, interpersonal and management skills. The study found that there were significant differences in the perception of IT Managers and Academicians on the desired level of proficiency of new IT recruits in 4 out of 7 skill sets analyzed, which were Interpersonal and Management Skills, Emerging Technologies Skills, IT Infrastructure Skills and Critical Thinking and Problem Solving Skills. IT Managers and Academicians differed in their views on the actual level of proficiency of new IT recruits too, as significant differences were found in their responses to 5 out of the 7 skill sets which were Interpersonal and Management Skills, Emerging Technologies Skills, Technical Management Skills, IT Infrastructure Skills and Critical Thinking and Problem Solving Skills. It surely does call for an active and productive partnership between the industry and the academia through meaningful communication, coordination and rigorous steps to bridge the gap and eventually to sustain and strengthen the inherent advantage that India has in the field of Information Technology. -
Educational Achievement of Socially and Economically Disadvantaged Children from Urban Slums of Bengaluru City
In the Indian context, marginalized and oppressed individuals often reside in slums newlineand on the streets, facing poor living conditions and inadequate facilities. While newlineurban areas boast elite lifestyles characterized by high levels of educational newlineattainment, access to the latest technologies, and substantial incomes, marginalized groups experience a significant lack of basic living standards and encounter limited access to essential services such as education, healthcare, and employment newlineopportunities. Education, in particular, poses one of the greatest challenges in slum newlineareas. Various factors, including socio-economic background, family characteristics, newlineand educational opportunities, can influence the academic performance of slum children. Additionally, teachers perceptions and classroom practices play crucial roles. The current study aims to explore how family characteristics, socio-economic background, educational opportunities, and teachers perceptions impact the educational achievements of slum children in Bengaluru city. To investigate educators perspectives on socially and economically disadvantaged children, a questionnaire was administered to teachers. The study utilized a mixed-method newlineresearch design to address its research questions. Quantitative data were collected newlinefrom 100 slum children and 100 non-slum children aged 6 to 14 years. During semistructured interviews, the researcher used an open-ended questionnaire to gather newlineresponses from principals and teachers. Thirty-six teachers working with various newlineschool boards in the Byrasandra and Siddapura areas were included in this study. newlineAdditionally, class observations were conducted to assess classroom interactions, the rapport between teachers and students, and levels of student involvement. A newlinepurposive random sampling technique was employed to select participants from the newlinestudy population. Data were meticulously collected and analyzed. -
EFFECT OF RADIATIVE TRANSFER ON RAYLEIGH-B??NARD CONVECTION IN A COUPLE-STRESS FLUID
The problem of Rayleigh-Benard convection in a couple-stress fluid with thermal radiation is studied within the framework of linear stability analysis. Only infinitesimal disturbances are considered. The linear stability analysis is based on the normal mode technique. The fluid between the boundaries absorbs and emits thermal radiation. The boundaries are treated as black bodies. The absorption coefficient of the fluid is assumed to be the same at all wavelengths and to be independent of the physical state. The principle of exchange of stabilities is valid and the existence of oscillatory instability is ruled out. The expression for the stationary Rayleigh number is obtained as a function of the governing parameters, viz., the wave number, the couple-stress parameter, the conduction-radiation parameter and the absorptivity parameter. The Galerkin method is used to determine the eigenvalues. The effect of various parameters on the stability of the fluid layer is discussed through figures and tables. -
EFFECT OF TEMPERATURE MODULATION ON RAYLEIGH-B??NARD CONVECTION IN A ROTATING LAYER OF A FERROMAGNETIC FLUID
The stability of a rotating horizontal layer of ferromagnetic fluid heated from below is examined when, in addition to a steady temperature difference between the walls of the layer, a time-dependent sinusoidal perturbation is applied to the wall temperatures. Only infinitesimal disturbances are considered. The effects of the oscillating temperature field are treated by a perturbation expansion in powers of the amplitude of the applied field. The onset criterion is derived when the condition for the principle of exchange of stabilities is valid. The shift in the critical Rayleigh number is calculated as a function of the frequency of modulation, magnetic parameters, Taylor number and Prandtl number. The effect of various parameters is found to be significant for moderate values of the frequency of modulation. It is shown that, when the thermal excitation is symmetric, supercritical motion is more pronounced for low Prandtl number ferro fluids. Further, for the case in which only the bottom wall temperature is modulated, the effect of rotation is to stabilize the system at low frequencies and the opposite is true for moderately large frequencies. The problem throws light on external means of controlling convection in ferromagnetic fluid applications. -
Effect of Animal Assisted Therapy among Children with Autism
Animal Assisted Therapy (AAT) is still at a very infancy stage of growth as a therapy mode in India. People are slowly getting to know of this and its positive effects for different populations like special kids, people in their old age, and terminally ill patients amongst the many others. Hence the choice to experience this is now gradually increasing in cities that provide AAT. In this present study the aim was to assess the effectiveness of AAT among children with autism. Specifically the focus was to see if AAT does affect the dimensions of communication, social and motor skills in children with autism. To do the same, a case study method was employed in order to derive an in-depth knowledge of the changes and improvements in the child. A multiple technique of data collection was employed wherein data was obtained via semi-structured interviews, observation and medical reports. The data obtained were transcribed and coded and put through a case analysis. The results obtained state that there have been improvements in the dimension of communication and social skills in the autistic children who were a part of this study. Motor skills however have not been significantly enhanced in almost all of them or rather the changes have not been very substantial. In view of the people providing information, the positive shift in these areas could be attributed to AAT but not solely as there could be other therapies and techniques that could have played a role in it. Key Words: Animal Assisted Therapy, Autism, Communication Skills, Social Skills, Motor Skills. -
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Effect Of Cooperative Learning Strategies on Self-Directed Learning and Reflective Thinking of Pre-Service Teachers
Cooperative learning (CL) research demonstrates its robustness. While acknowledging the empirical benefits, there is room for improvement in implementing CL in teacher education classrooms. Teacher educators often resist adopting CL, favouring the frontal teaching method. The cultivation of self-directed learning and reflective newlinethinking is crucial for pre-service teachers (PSTs) to evolve into lifelong learners, newlinemeeting the demands of 21st-century classrooms. Online cooperative learning (OCL) newlineplays a vital role in enhancing essential skill sets such as collaboration, digital newlineproficiency, communication, and interaction among pre-service teachers. This study newlineunfolded in two phases. The initial pilot study, utilizing a concurrent triangulation newlinemixed-method research design, delved into perceived challenges faced by teacher newlineeducators in India regarding cooperative learning implementation. The subsequent newlineexperimental stage employed a quasi-experimental non-equivalent control group newlinedesign to investigate the impact of OCL strategies on self-directed learning (SDL) and reflective thinking (RT) among Indian pre-service teachers. Following the newlineintervention with OCL modules, the researcher also assessed pre-service teachers newlinesatisfaction and perceptions towards OCL, utilizing a mixed-method research approach with concurrent triangulation. The sample for experimental stage encompassed 130 pre-service teachers from two teacher education colleges affiliated with Mangalore University, Karnataka, India. The researcher constructed OCL intervention modules for the study and experts validated it. The researcher adopted standardized instrument for measuring SDL by Acar et al. (2016), and standardised instrument for measuring RT by Kember et al. (2000). The pilot study revealed that teacher educators perceived challenges at an average rate of 63% due to teacher challenges, learner challenges, curriculum syllabus, and administrative challenges.