Full Text Theses - STA (2022 onwards)
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Item Furfural Hydrogenation Using Bimetallic Supported Nanocatalysts(2022) Mark, Nakisha, PatriciaIn a drive towards sustainable chemicals and fuels many biomass upgrading strategies have emerged, with furfural being an important platform chemical. Commercial application of furfural derived bio-fuels has been hindered by challenges with catalyst activity and stability in the liquid phase. The interplay between the nature of the support and nanoparticles has been explored, but the exploration of the catalyst synthesis methods in this area is not common. Therefore, catalysts synthesised using a conventional method- incipient wetness impregnation (IWI) and less- conventional methods- chemical vapour impregnation (CVI), solvothermal (S) and hybrid (H) techniques were employed in the hydrogenation of furfural to fuel precursors under mild aqueous conditions (403K, 3MPa). These materials, containing low weight percent of precious and non- precious metal active sites were structurally characterised using several techniques (ICP, BET, TEM, XRD and XPS), which showed variation in morphology according to the synthesis method. It was demonstrated that the cooperation between non-precious and precious metals can determine which pathway dominates in the reaction, for example the RuCu-IWI catalyst yield 69% 1,5pentanediol (1,5PDIOL) whilst the Ru-IWI catalyst yield 75% 1,4 pentanediol (1,4PDIOL). The effects of support variation showed changes in the product profiles such as the RuFe-CVI catalyst yield 50% tetrahydrofurfuryl alcohol (THFA) whilst the RuFe-H catalyst yield 99% furfuryl alcohol (FOL). The impact each synthesis method has on furfural hydrogenation was observed, for instance the CuFe catalysts were selective towards FOL but its yield differs in each method, IWI- 54%, CVI- 35%, S- 73% and H- 99%. The recyclability of the less-conventional catalysts was examined through reusability and regeneration, and it was observed that the CVI catalysts had the most potential of being recyclable. Through the thoughtful catalyst design this research edges commercial furfural hydrogenation under green conditions ever closer to reality.Item The Implementation of the Caribbean Vocational Qualification (CVQ) in Secondary Schools of Selected CARICOM States(2022) Whiteman, PaulineThe study explored stakeholders’ perceptions about the CVQ to determine its impact on the delivery and assessment for the CVQ level 1 among secondary schools in six CARICOM states. Stakeholders’ experiences in the delivery and assessment for the CVQ were also investigated to determine the extent to which approaches employed in the delivery and assessment for the CVQ were in accordance with Competency-based Education and Training (CBET). The study employed a mixed methodology where the dominant qualitative phase explored perceptions and experiences of students, teachers, Heads of Departments/internal verifiers and principals/administrators about the CVQ level 1 programme by conducting focus group sessions and interviews. The quantitative phase surveyed students, teachers and internal verifiers to determine if approaches employed in the delivery and assessment of the CVQ were in accordance with CBET. Findings of the study were consistent with those found in the literature such as the existence of a negative perception of TVET and by extension the CVQ and challenges in timetabling and resourcing the delivery and assessment for the CVQ. The results of the study unearthed some good practices for cushioning the impact of limited resources such as implementation of the Self-Sufficient TVET School and resource sharing practices. In general, from the perspectives of students, teachers and internal verifiers, delivery and assessment approaches were consistent with CBET. While there were no statistically significant differences among teachers and internal verifiers regarding resources to support CBET, curriculum delivery and assessment practices, there were significant differences among students in all three variables. Recommendations were proposed for policy, practice and future research with a view to bolster the CVQ system for a more coherent, efficient and effective CVQ level 1 programme. Recommendations for policy focused on uptake of the CVQ level 1, clear delineation of roles and responsibilities of stakeholders, and resourcing for the CVQ level 1. Given the findings in this study, future research should focus on how CVQ level 1 can be implemented in a more economical manner, the feasibility of preparing students for the pursuit of the CVQ level 1 by implementing foundation vocational programmes in the lower forms, the potential for diverse teamteaching/ networking across institutions/industry/regions using available ICT infrastructure, the viability of e-Assessments for the CVQ and the effectiveness and cost-effectiveness of the CVQ level 1 programme.Item Prevalence and characteristics of Salmonella spp. isolated during broiler production, processing and sale in Trinidad and Tobago using the ‘farm to fork’ approach(2023) Khan, Anisa, SarahGlobally, Salmonella spp. is an important pathogen associated with foodborne diseases but there is a dearth on information on the occurrence and characteristics of Salmonella spp. in the country. The farm-to-fork investigation, using cross-sectional studies, determined the prevalence and characteristics of Salmonella in imported fertile hatching eggs, day-old chicks at hatcheries, broilers on farms, processing plants and chicken sold at retail outlets, using phenotypic methods and whole genome sequencing (WGS). At the level of broiler production, the prevalence of Salmonella was 0.0%, 7.6% and 2.8% for imported fertile eggs, hatcheries, and farms, respectively (p=0.006). The highest frequency of isolation of Salmonella was 28.0% and 2.2% in stillborn chicks and cloacal swabs, respectively, and the predominant serovars isolated were Kentucky (83.3%) and Infantis (62.5%). At the processing plants, the overall prevalence of Salmonella was 27.0%. S. Enteritidis, Javiana and Infantis were the predominant serotypes isolated, accounting for 20.8%, 16.7% and 12.5%, respectively, of the serotypes. The prevalence of Salmonella spp. in chicken carcasses sampled from cottage poultry processors and supermarkets was 20.5% and 8.3% respectively (p<0.001); the predominant serotypes isolated were Kentucky (30.9%) and Javiana (22.7%). Overall, all isolates exhibited resistance to one or more of the 16 antimicrobial agents tested. Whole genome sequencing (WGS) of 146 isolates that originated from the three levels of the industry was conducted. Antimicrobial resistance genes conferring resistance to aminoglycosides, cephalosporins, peptides, sulfonamides and antiseptics were detected. Overall, virulence factors associated with secretion system and fimbrial adherence determinants accounted for 69.3% and 29.2% of the counts, respectively. Analysis of the core genome phylogenies revealed reliable clustering among isolates of serovars detected within and between sampling levels. The use of WGS confirmed the genetic relatedness and transmission of Salmonella serovars contaminating chickens in broiler processing and retailing in the country, with zoonotic and food safety implications.Item Exploring Educators’ Perceptions about Necessary Supports for Inclusive Practice: Development and Assessment of a Conceptual Model(2023) Ramoutar, Amanda, MichelleThis study addresses an area of research that has not been well described within inclusive education. In the ethic march towards inclusion in schools in the CARICOM region, educators have been left feeling less than confident in their ability to fulfill their responsibilities in meeting students’ needs due to the lack of facilitating conditions. The purpose of this two-phase, exploratory sequential mixed-methods study was to explore participant views about the provision of supports and to use this information to develop and test a model of necessary supports for educators’ inclusive practice. The first phase was a qualitative exploration of which supports are deemed essential to improve inclusive practice, in which individual and focus group interview data were collected from a sample of 10 education directors. Since there are no existing instruments to assess the provision of supports for inclusive practice, the themes from the qualitative findings were used to develop an instrument so that a series of hypotheses could be tested that relate to educators’ views about the key categories of supports necessary, and the relationship between supports and inclusive practice. Quantitative data collection for the second phase of the study was from a larger sample group of educators consisting of education directors, principals, and classroom teachers. Survey data were analyzed using basic and inferential statistical methods. The study found that five categories of supports are necessary for inclusive practice: an administrative plan of action, an educator efficacy mechanism, a coordinated response to student functionality, ecological infrastructure, and sensitization and advocacy. Further, the study revealed that these all impact educators’ inclusive practice.Item A Finite Element Study of Steel Rafter to Concrete Ring Beam Connections Used in Trinidad and Tobago(2022) Daniel, AldenRafter to ring beam connections are the most critical connections in a roof as their failure can result in dislodgement of the entire roof along with its framing and covering. The aim of this study was to conduct a finite element analysis study on the performance of some of the non-coded steel rafter to concrete ring beam connections used in Trinidad and Tobago. The most popular of these connections involve using steel rebars that are cast into the ring beam and subsequently welded to the rafter. Nine versions of this connection were identified and categorized as Type 2 & Type 3. The Type 2 Connections are those in which the rebars are welded to the top flange of the rafter and the Type 3 Connections are those in which the rebars are welded to the bottom flange of the rafter. The Type 2 and Type 3 connections consisted of several variations including mechanically anchoring the rebar to the rafter without welds, using one and two rebars, varying of the rebar embedment depth and using 90 degree and straight rebars. A Type 1 standard, code-compliant, bolted-endplate connection was used as the control for the investigation. The connections were analysed using “ABAQUS” and the maximum load resistances were compared with computed category 1 hurricane loads for this region. The load capacities of all the connections were found to be lower than the control connection but were still adequate for hurricane category 1 loads, with the exception of the connection in which the rebars were mechanically anchored to the rafter without welds. The Type 2 connections were less stiff, experienced larger rafter displacements, inflicted less damage on the concrete ring beam, and required less rebar embedment to prevent pull-out failure than the Type 3 connectionsItem Design and development of an integrated land management model in GuyanaAli, Mohamed, Irfaan