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Numerical Investigation of Heat Transfer Performance in Cylindrical Pipes using Wall Grooves and Nanofluids
No full textOptimising heat exchangers by enhancing heat transfer, reducing heat transfer time, and improving fluid thermal properties is essential for maximising energy efficiency. While grooves and nanofluids are promising solutions, their combined effects introduce challenges, such as increased pumping power requirements and inconsistent numerical modelling results. This study addresses these issues by numerically analysing a single-tube heat exchanger under turbulent forced convection by incorporating grooves and nanofluids. This numerical investigation uses single and multiphase models alongside the Realizable k-ε and SST k-ω turbulence models to capture the thermal and hydrodynamic behaviour of the single-tube heat exchanger. Initial validation with experimental data for a smooth tube and a smooth tube with circular grooves using water at Re = 10,000 to 60,000 with an average error of less than 8% confirmed the reliability of the models.
This study assessed different groove shapes such as circular, triangular, rectangular, trapezoidal, and hybrid combinations to enhance heat transfer in corrugated tubes. The trapezoidal grooves achieved the highest Nusselt number, with a 37.92% improvement compared to a smooth tube, for Reynolds numbers ranging from 10 × 10³ to 60 × 10³ . However, triangular grooves exhibited the maximum thermal performance factor (PEC) due to the lower pressure drop compared to other groove shapes and hybrid combinations. Additionally, optimising rectangular grooves by adding curvature reduced pressure drop by 10.76% and improved the heat transfer coefficient of the single-tube heat exchanger by 13.4%, although triangular grooves remained superior.
This study evaluated the impact of turbulent models on nanofluid simulations, revealing significant variations in the Nusselt number, friction factor, turbulent kinetic energy, and wall shear stress. The single-phase model with the Realizable k-ε turbulence model showed an average error under 5% in predicting the Nusselt number and was closer to experimental data, outperforming the two-phase models (Eulerian and Mixture). In addition, the Al₂O₃-based hybrid nanofluids demonstrated up to 83.8% enhancement in heat transfer compared to pure water in a smooth tube at Re = 60,000. Finally, the combination of efficient triangular grooves with a 1% Al₂O₃-CuO/Water-EG hybrid nanofluid enhanced heat transfer rates by a factor of 2.14 in PEC values
Perceptions of diabetic retinopathy patients on the management of diabetic retinopathy (DR) in South Tarawa, Kiribati: A qualitative study
No full textDiabetic Retinopathy (DR) is one of the most common causes of legal blindness in developing countries, particularly between the ages of 20 to 65 years. Kiribati is currently facing the burden of DR where more than 5% of diabetes patients had experienced negative impacts of DR. This study aimed to explore the perceptions of DR patients on DR management in South Tarawa, Kiribati. This qualitative study was carried out at the Eye clinic in Tarawa Central Hospital from the 29 th of August to 23 rd of September, 2022. Patients diagnosed with DR of both sexes aged ≥ 18 years were purposively selected to participate in this study. 27 DR patients were recruited and interviewed using a semi-structured open-ended questionnaire. Manual thematic analysis was applied to observe the similarities and differences in answers obtained from interview transcripts. A total of 27 DR patients were enrolled in this study. The majority of patients were between the age of 50–59 (37%) and were males (62%). The findings highlighted a lack of knowledge and awareness of DR management among patients with diabetes in Kiribati. Poor health education, in-availability and lack of access to eye care services, patient belief, and healthcare system issues were identified as the most crucial contributing barriers. These data characterized the need for more communication campaigns including specific messaging on DR and its management to increase diabetes patients’ awareness of the importance of DR treatments
Green Building Practices: Fuzzy Synthetic Evaluation of the Drivers of Deforestation and Forest Degradation in a Developing Economy
No full textSince 1990, approximately 420 million hectares of forest have been lost worldwide due to land conversion for various uses, including agriculture, infrastructure development, urbanization, and other human activities. This study aims to investigate the critical drivers contributing to deforestation and forest degradation (DFD) in Ondo State, Nigeria, thereby identifying areas where REDD+ (Reducing Emissions from Deforestation and Forest Degradation) interventions could be most effective in reducing greenhouse gas emissions, particularly carbon dioxide (CO2), which is released through forest loss and degradation. A questionnaire survey was used to obtain data from construction professionals such as architects, engineers, builders, quantity surveyors, and project managers. Collected data were analyzed using frequencies and percentages to report the background information of professionals, Mean Item Scores (MIS) to rank critical drivers of DFD, and Fuzzy Synthetic Evaluation (FSE) to identify the most critical drivers. FSE analysis revealed that DFD is primarily motivated by agricultural expansion (including cattle ranching and shifting cultivation) and infrastructure extension (particularly transportation networks and market and service infrastructure) among the proximate drivers. The analysis also identified demographic, economic, and policy and institutional factors as the most significant underlying drivers. The emphasis on agricultural expansion and infrastructure extension suggests that targeted interventions in these areas could significantly mitigate DFD in the study site under consideration. This may involve implementing stricter regulations and incentives to promote sustainable land use practices among farmers and landowners. Additionally, integrating environmental impact assessments into infrastructure projects can help minimize forest loss associated with road construction and urban expansion. This study introduces an innovative approach by applying the Geist and Lambin conceptual framework of ‘proximate causes and underlying driving forces’. It is among the pioneering studies conducted in the study area to comprehensively analyze the drivers contributing to DFD using these frameworks. Although conducted in Ondo State, Nigeria, the findings can be extrapolated to similar regions facing similar challenges of DFD worldwide
A Systemic Digital Transformation for Smart Net-Zero Cities: A State-of-the-Art Review
No full textThis paper presents a state-of-the-art review of digital transformation for developing smart net-zero cities, highlighting the significance of systems thinking and the key components of digital transformation including people, data, technology and process. Urban areas are experiencing increasing challenges from rapid growth and climate issues, making digital transformation a crucial strategy for enhancing sustainability and efficiency. In this context, systems thinking is essential, as it provides a holistic perspective that acknowledges the interdependence of urban sectors which can facilitate a more comprehensive, adaptable, and strategically integrated approach. This review examines findings from 22 sources and proposes a framework to investigate and represent the necessity of a digital transformation approach that effectively balances these elements and promotes a systems thinking approach. Also, by examining the findings from a systems thinking perspective, this research analyses the potential of effective digital transformation to support the complex needs of smart net-zero city developments. The findings indicate a widespread recognition of the digital transformation potential as a practical implementation strategy. It is imperative to formulate digital transformation strategies that are practical and comprehensively incorporate all elements: people, technology, processes, and data. Additionally, the review highlights the critical role of systems thinking in the development of these digital transformations as it facilitates the integration of interdependent urban sectors, including energy, transformation, and building, to achieve a holistic and integrated transformation
A Systematic Literature Review on Empathy-led Measure of Readiness for Digital Adoption Towards a Sustainable and Happy Workforce
No full textThe paper aims to review the transdisciplinary literature to understand and benchmark how differentdisciplines measure individuals' emotions and perceptions of technology use and usefulness in the preadoptionstages of digitalisation. The systematic review combines literature from multiple disciplines todetermine how individuals' psychological and emotional responses indicate their readiness to adopt digitaltechnology before it is introduced (pre-adoption stage).The findings are from a systematic literature review that identified the psychological, emotional, andintrinsic variables in individuals that influence people's readiness to adopt digital technology. These variablesare grouped and selected to articulate the perception of the usefulness of technology and the feeling usersattach to that technology in the pre-adoption stage. The paper concludes with the dependent, independent,mediating and moderating variables influencing people’s perception of new technology and their adoption of it,which could hinder or facilitate the transformation towards a ‘happy and sustainable workforce’.The review supported the need to have a more empathy-led transdisciplinary methodology to extract andunderstand emotions and intrinsic factors that defined readiness in individuals in pre-adoption stages. Thisconcluded in the creation of a methodology which combined Psychology, design, and engineering methods toextract and measure emotions in individuals.The paper aims to review the transdisciplinary literature to understand and benchmark how differentdisciplines measure individuals' emotions and perceptions of technology use and usefulness in the preadoptionstages of digitalisation. The systematic review combines literature from multiple disciplines todetermine how individuals' psychological and emotional responses indicate their readiness to adopt digitaltechnology before it is introduced (pre-adoption stage).The findings are from a systematic literature review that identified the psychological, emotional, andintrinsic variables in individuals that influence people's readiness to adopt digital technology. These variablesare grouped and selected to articulate the perception of the usefulness of technology and the feeling usersattach to that technology in the pre-adoption stage. The paper concludes with the dependent, independent,mediating and moderating variables influencing people’s perception of new technology and their adoption of it,which could hinder or facilitate the transformation towards a ‘happy and sustainable workforce’.The review supported the need to have a more empathy-led transdisciplinary methodology to extract andunderstand emotions and intrinsic factors that defined readiness in individuals in pre-adoption stages. Thisconcluded in the creation of a methodology which combined Psychology, design, and engineering methods toextract and measure emotions in individuals
Diabetes Therapeutics of Prebiotic Soluble Dietary Fibre and Antioxidant Anthocyanin Supplement in Patients with Type 2 Diabetes: Randomised Placebo-Controlled Clinical Trial
No full textBackground: Antioxidants and prebiotics are popular functional foods known for their distinct physiological ameliorating benefits on type 2 diabetes mellitus (T2DM). Whether and how a combined antioxidant-prebiotic supplement affects primary and secondary T2DM outcomes is not known. Objectives: We investigated the therapeutic effects of an antioxidant (anthocyanin from riceberry rice) combined with prebiotics (dietary fibre from rice bran and Jerusalem artichoke) on glucose control, lipid profile, oxidative stress, inflammation, and cardiorespiratory fitness in T2DM patients. Methods: A total of 60 T2DM patients were randomly assigned to receive antioxidant/prebiotic (supplement group, SG) or maltodextrin (control group, CG), (two capsules (350 mg)/meal after three meals and before bedtime, 2.8 g/day), for 60 days. Venous blood samples were collected at baseline and after 60 days intervention to assess blood metabolic variables (glucose, insulin, and lipid profiles, renal and liver functions, oxidative stress, inflammation). Nutrition status, anthropometry, body composition (DEXA) and cardiorespiratory fitness were also measured. Results: Analysis of co-variance showed superior effects on T2DM’s glucose and lipid profiles in the SG compared with the CG including reduced fasting blood glucose (p = 0.01 within-group effects, p = 0.03 interaction effects), reduced glycated haemoglobin (p = 0.004 within-group effects, p = 0.002 interaction), and reduced low density lipoprotein (p = 0.006 within-group effects, p = 0.02 interaction effects). No significant change was found within the CG for any of these parameters. Kidney function’s glomerular filtration rate was also improved in the SG (p = 0.01 within-group effects), but not in the placebo CG. Intermediatory biomarkers of oxidative stress, inflammation, and cardiorespiratory fitness were not significantly affected in either group with no interaction effects. No adverse effects were detected following the 60-day supplementation intervention. Conclusions: The findings suggest that a combined anthocyanin-fibre may be promoted as an adjacent therapy in patients with T2DM, but the intermediary mechanisms of action require further research
The impact of alcohol sales on perceptions of security amongst Brazilian football fans
No full textIn 2003, the Estatuto de Defesa do Torcedor (Fans’ Bill of Rights Act) was introduced in an effort to curb fan violence, resulting in the prohibition of alcohol sales in Brazilian sports stadiums. This study uses Santos FC as a case study to explore football fans’ perceptions of the link between alcohol and violence, and investigate how introducing alcohol sales may potentially impact future attendance. Exploratory Factor Analysis and Ordinal Logistic Regression Models based on an online survey (n = 562) are used to identify factors influencing Santos fans’ decisions about whether to attend football matches where alcohol is sold. The main driver for a change in attendance is the perception of the link between alcohol consumption and violence. This relationship is mitigated by individual fans’ attitudes to alcohol and their likelihood of avoiding matches if violence increases
Lean implementation case study for manual order picking and packing in warehousing operations
No full textPurpose
This study aims to analyse the application of lean thinking in warehousing operations’ picking and packing processes.
Design/methodology/approach
The research design used is a conceptual framework based on the literature for lean practitioners’ guidance.
Findings
The results of the empirical study reveal an increase in efficiency of 30% in picking and packing operations when analysing and decreasing the non-value-added processes in this case study
Research limitations/implications
The proposed framework has not been implemented in a wide range of operations. The findings are limited due to the focused feature of the case study. Additional cost–benefit analysis can be investigated.
Practical implications
This study can guide warehousing logistics practitioners towards achieving excellence in manual picking and packing operations through lean thinking implementation.
Originality/value
This study overcomes the lack of a structured framework for lean manual order picking and packing and evaluates the potential of a set of lean and process analysis tools to increase the efficiency of order picking and packing
Design and testing of a test rig for tubular joints hot-spot stress determination
No full textCircular hollow section (CHS) members are widely used in structural applications due to their high stiffness, low drag, uniform response under various loading directions, and aesthetically pleasing appearance. However, the complex stress and strain behaviour at the intersections of CHS members, known as tubular joints, is challenging to approximate analytically, necessitating numerical methods for analysis. Experimental validation of these models is essential but often requires sophisticated and costly setups that are not readily available. Although extensive research has been conducted on CHS joints, including validation of numerical and empirical models for determining stress concentration factors (SCFs), gaps remain in understanding SCF behaviour under complex loading scenarios. This study introduces a simplified test rig for investigating hot-spot stress and SCF behaviour in CHS joints for mono-, bi-, and tri-planar loading conditions. Loads are applied using dead weights, and responses are measured with strain gauges. The proposed setup has been validated against finite element analysis results. It accommodates joints made of various materials, such as steel, aluminium, or acrylic, and supports the investigation of SCFs under different combinations of axial, in-plane, and out-of-plane bending loads
The influence of new public management on the police first-line manager: exploring the challenges faced by practitioner managers
No full textSince the introduction of New Public Management (NPM), police sergeants have experienced significant role expansion, increasingly required to deliver organizational strategies, implement managerial policies, and facilitate organizational change. A study of police sergeants identified a conflict between management and operational responsibilities. Participants described policing as a mechanistic organization heavily weighted towards middle and upper management, impeding their autonomy. Yet, aired strong support for the retention of hierarchy. Participants expressed frustration at being excluded from critical decisions, negatively affecting their ability to facilitate change. This provides important insight into the impact of NPM on policing