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An investigation on shell-side thermal–hydraulic performance of helically coiled tube heat exchanger for deep underground space
Get PDFHelically coiled tube heat exchanger (HCHE) was extensively used to enhance the thermal environment of deep underground space. The inefficiency of heat transfer in the mine cooling system results in increased operational energy consumption. To enhance heat utilization, this study examines the impact of air temperature, air velocity, coil diameter, pitch, and elliptical tube aspect ratio on the shell-side thermal performance of HCHE through experimental and numerical analysis. The performance evaluation criterion (PEC) and field synergy are introduced to provide a comprehensive assessment of performance. Results suggest that the air velocity can more significantly affect the thermal performance of HCHE than air temperature. Augmenting the coil diameter from 30 − 40 mm and coil pitch from 7.5 − 9.0 mm led to an increase in the Nu number by 16.5 % and 6.7 %, as well as an increase in friction factor f by 575.2 % and 147.1 %, while a reduction in PEC by 38.4 % and 21.1 % when the air velocity is 5 m/s, respectively. For the helically coiled elliptical-tube heat exchanger (HCHE-E), the thermal performance is significantly dependent on the long axis's direction and its aspect ratio. When the air velocity is 3 m/s, the increase in aspect ratio from 1.0 to 1.8 resulted in a decrease and increase in Nu by 14.7 % and 14.6 %, an increase and decrease in PEC by 24.5 % and 28.4 %, as well as a reduction and increase in f by 31.5 % and 48.1 % for the long axle in the horizontal and vertical directions, respectively. The PEC for HCHE is not significantly dependent on the air velocity. The increase in air velocity can result in the augment in PEC of HCHE-E regardless of long axis's direction. The variation of synergy angle is consistent with the change of Nu. These findings offer valuable insights for optimizing the design parameters of HCHE in deep underground spaces
Students preferences for teaching and exam delivery modes in accounting education post COVID 19 pandemic
Get PDFThe COVID-19 pandemic has sparked a revolution in the delivery of modules in higher education. This paper aims to answer the research question: What are the preferences of undergraduate accounting and finance students regarding teaching delivery and exam modes following the COVID-19 pandemic lockdown? Specifically, we focus on campus, online synchronous, and hybrid synchronous teaching delivery and exam modes. To address this research question, we conducted an online questionnaire surveying students at a U. K. university. Our data show that modules involving calculations, such as financial accounting, are preferred to be taught on campus, whereas theoretical modules like business law are preferred to be taught online. Additionally, the data reveal reasons for these preferences, including community learning, isolation, concentration, and access to recordings. This research contributes valuable insights into optimising accounting education. We advocate for flexibility in both teaching and exam delivery within accounting education, recognising the diverse needs of students
Understanding the effect of saturated gases on catalytic performance of graphitic‐carbon nitride (g‐C<sub>3</sub>N<sub>4</sub>) for H<sub>2</sub>O<sub>2</sub> generation and dye degradation in the presence of ultrasound
Get PDFThis paper examines the effect of saturated gases on H2O2 generation and dye degradation using graphitic‐carbon nitride (g‐C3N4) as a piezoelectric catalyst. A detailed catalytic evaluation was carried out using a double‐bath sono‐reactor, where the performance of g‐C3N4 for H2O2 production and degradation of rhodamine B and indigo carmine dyes was evaluated for a range of catalyst dosage levels and saturated gases. Specific gases were selected to understand their role in the sonochemical production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and to elucidate the potential catalytic mechanism. The use of an Ar‐O2 gas mixture led to the highest yield for H2O2 production and dye degradation due to the positive effect of argon and oxygen in the generation of H2O2 and reactive oxygen species, respectively. The presence of nitrogen in both air and in an Ar‐air mixture increased H2O2 generation since reactive nitrogen species improved the conversion of •OH into H2O2. In contrast, air and Ar‐air negatively influenced the generation of ROS, which resulted in a low rate of dye degradation. This work provides new insights of the mechanisms of sonochemical and piezocatalytic processes in the use of graphitic‐carbon nitride in catalytic applications.This article is protected by copyright. All rights reserved
Evaluating the variation characteristics of ecological resilience along expressways in developing countries: the case of the Phnom Penh-Sihanoukville Expressway in Cambodia
Get PDFExpressway construction has caused a significant threat to the ecological environment in developing countries, and therefore the variation characteristics of ecological resilience along the expressway in developing countries are of major importance. This empirical study focuses on a typical area within a 2-km range of the Phnom Penh-Sihanoukville Expressway in Cambodia and uses remote sensing and geographic information systems (GIS) technology to analyze the variation characteristics of ecological resilience along the expressway. The results of the study reveal that due to the construction of expressways, the land use types transferred into or out of the land use types increase and furthermore the land use types show a trend of decreasing natural attributes and increasing human attributes. It is found that expressway construction has an observed effect on the transfer rate of the center of gravity of land use type, and the direction of the center of gravity shifts in the direction of expressway construction. The impact of construction on the ecological resilience of the western region with higher vegetation coverage was higher than that of the eastern region with higher urbanization. The research develops a theoretical evaluation model based on land use type of the variation characteristics of ecological resilience along the expressway, which can be used to enable the sustainability of expressway construction and maintain the regional ecological environment
Unobservable Costly Effort in Security Design
Get PDFI introduce unobservable costly effort into the canonical signalling model of security design. The choice of effort determines the quality of the security and creates an additional optimisation problem the firm must solve. My main result is that both optimal effort and optimal profits are decreasing in the firm’s preference for liquidity. I also show that optimal effort is greater under symmetric information. My approach provides a theoretical explanation for empirical results that cannot be obtained within the standard signalling framework. In addition, I extend existing methods to solve signalling models with endogenous private information
Troubling French Feminist Diplomacy with the National Context
Get PDFFeminist Foreign Policy is increasingly a strategic tool for states to (re)brand themselves as ‘feminist’ actors and norm-setters on the international stage. In the FFP story, states claim the intellectual foundation of feminism and construct themselves as bastions of gender equality. Yet, by imagining feminism and gender equality to be ‘homed’ in these states, FFP obscures real and potential gendered tensions that occur at the domestic level. This chapter illustrates this problem with ‘French feminist diplomacy’, a priority in Macron’s presidency since 2018, and draws on a narrative conceptual framework to trouble the narrative that France is entirely and unequivocally a feminist state. I focus on four domestic issues which reveal France’s internal struggles with gender and feminism: the ‘modèle Républicain’, the democratisation of sexual politics, the racialisation of gender equality, and the rise of (state-sponsored) anti-genderism since the 2000s. By shedding light on a complex politics of gender in the French national context, this chapter constitutes a contribution to postcolonial scholarship on Feminist Foreign Policy, a growing body of literature that challenges the idea that feminism and gender equality belongs to the Global North
Architectural blueprint for heterogeneity-resilient federated learning
Get PDFThis paper proposes a novel three-tier architecture for federated learning to optimize edge computing environments. The proposed architecture addresses the challenges associated with client data heterogeneity and computational constraints. It introduces a scalable, privacy-preserving framework that enhances the efficiency of distributed machine learning. Through experimentation, the paper demonstrates the architecture’s capability to manage non-IID data sets more effectively than traditional federated learning models. Additionally, the paper highlights the potential of this innovative approach to significantly improve model accuracy, reduce communication overhead, and facilitate broader adoption of federated learning technologies
A–Z of prescribing for children: L – Legal considerations
Get PDFThis series focuses on aspects of prescribing for neonates, children and young people, from A–Z. Aspects of pharmacokinetics will be considered, alongside legal considerations, consent and medications in schools
A–Z of prescribing for children: G – Gillick competence
Get PDFThis series focuses on aspects of prescribing for neonates, children and young people, from A–Z. Aspects of pharmacokinetics will be considered, alongside legal considerations, consent and medications in school
Moving beyond myths and realities: impact of the 5C’s strategies on the internationalization of higher education in the context of COVID-19
Get PDFThe COVID-19 pandemic impacted almost all areas of our lives, including the internationalization of higher education. Therefore, enabling the internationalization of higher education is one of the biggest challenges for academic institutions, and in this context, there is a need to move beyond myths and realities. Owing to the scarcity of research in the domain, this study aims to identify various critical strategies and empirically examine their impact on the internationalization of higher education. For this purpose, a comprehensive literature review was conducted to explore strategies and develop a theoretical framework. To test research hypotheses, this study employed an explanatory research design utilizing a survey instrument methodology to collect data from 253 respondents from both the public and private sector universities in Pakistan. The measures of the internationalization of higher education were adopted from earlier studies while an instrument was developed to measure strategies on a 5-point Likert scale. The reliability and validity of data were ensured, and correlation and regression analyses were utilized to test hypotheses, in addition to validation of hypotheses through AMOS and PLS-SEM. Findings revealed a significant and positive impact of communicating, cooperating, coordinating, collaborating, and continuing strategies (5C’s) in enhancing the internationalization of higher education. Also, the finding implies that an integrated policy through the adoption of the 5C’s strategies needs to be implemented by academic institutions to overcome the challenges of the internationalization of higher education