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    Mathematical modelling of couple stress fluid flow around a semi-permeable sphere enclosing a solid core

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    The focus of this article is to study theoretically the steady-axisymmetric creeping flow dynamics of a couple stress fluid external to a semi-permeable sphere containing a solid core. This problem is motivated by emulsion hydrodynamics in chemical engineering where rheological behaviour often arises in addition to porous media effects. The non-Newtonian Stokes' couple stress fluid model features couple stresses and body couples that are absent in the classical Navier-Stokes viscous model. It provides a robust framework for simulating emulsions, complex suspensions and other liquids which possess microstructure. The physical regime is delineated into two zones-the interior of the semi-permeable zone (region II) which engulfs the solid core and the external couple stress fluid zone (region I). The model is formulated using a spherical polar coordinate system in terms of the stream function ψ. The Brinkman-extended Darcy model is deployed for the porous medium hydrodynamics and isotropic permeability is considered. Analytical expressions are derived for dimensionless pressure, tangential stress and the couple stress components using the method of separation of variables and Gegenbauer functions of the first kind. The integration constants are evaluated with appropriate boundary conditions on the inner and outer boundary of the semi-permeable zone with the aid of Mathematica symbolic software. Solutions for the drag force exerted by the couple stress fluid on the semi-permeable sphere and volumetric flow rate are also derived with corresponding expressions for the drag coefficient and non-dimensional volumetric flow rate. The influence of permeability (k), separation parameter (l), couple stress viscosity coefficient (), couple stress inverse length dependent parameter (= (/)) and couple stress viscosity ratio ( = / /) on all key variables is studied graphically. Additionally streamline contours are computed for a range of parameters including inverse permeability parameter (=1/k). The computations show that increasing couple stress inverse length dependent parameter () greatly reduces the dimensionless volumetric flow rate in particular at high values of separation parameter (l). Flow rate is however markedly enhanced with permeability (k) and also couple stress viscosity parameter (). In the presence of the solid core a much greater drag coefficient is observed at all values of couple stress inverse length dependent parameter () relative to the case without a solid core. A significant distortion in streamlines is computed with increasing separation parameter (l) with a dual vortex structure emanating. With greater couple stress viscosity parameter () no tangible modification is observed in the streamline contours. The present work generalizes the earlier study of Krishnan and Shukla (2021) to consider a semi-permeable (porous medium) outer sphere and furthermore presents detailed streamline visualizations of the creeping flow for a range of emerging parameters of relevance to non-Newtonian chemical engineering processes including emulsion droplet dynamics in porous materials

    Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration

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    Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole‐ecosystem fragmentation experiment in the Brazilian Amazon over a 2‐year period, across 33 sites, comprising continuous old‐growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior‐edge‐matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species‐level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species‐specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species‐level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old‐growth forest

    Modern welfare in the United Kingdom is a universal (dis)credit to Beveridge. Is it time for a basic income?

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    Universal Credit signalled a revolution in the delivery and costs of welfare provisioning. UC aimed to reduce spending on welfare, but in doing so now threatens the stability of a functioning and cohesive society. Over recent years, and most notably during the COVID‐19 pandemic, it has become ever clearer that adequate social security is vital to the functioning of society, as well as to the health and well‐being of the population. Yet this period has also served to highlight the fragility and insufficiency of welfare in the United Kingdom. This article explores how the current welfare crisis, is associated with UC. In this article, we also consider the uncertainty that UC has created in most recipients. We argue that there are other ways to support the most vulnerable in society, and that we are now at that critical juncture in needing to make significant change. Universal Basic Income (UBI) offers one such alternative by offering stable, individual, non‐means tested, and unconditional money transfers, to all citizens. Over the last decade, there have been multiple experiments around the world trialling basic income, each of which has a specific focus, or target population, as different elements of a UBI were scrutinised. In this article, we reflect upon what we consider to be the potential shortcomings of the current welfare system in the United Kingdom as a move away from its origin, arguing that the United Kingdom is now primed for UBI to be considered a fair and legitimate way to provide social security

    Flipping Failure: A case study on building resilience and confidence through 'Failureship Strategies' in theory and practice at the University of Salford.

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    This paper presents the Flipping Failure project, which aims to challenge the negative perception of failure and promote its benefits for building resilience, insight, and action. The project involved students and staff who participated in failure-focused events that explored different aspects of failure in various contexts. We discuss the theory and practice of flipping failure to present it more positively and provide a practical toolkit with resources to help others adopt failure as a transferable skill-set. In sharing the outcomes and insights of the project, and its further development at The Festival of Learning and Teaching, we suggest ways to enhance and extend this work in the future

    Circular Economy in Construction - A Stakeholder Perspective

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    Natural resources are finite, therefore, their efficient use is necessary for a sustainable future in the construction industry. Making better use of the materials at our disposal is paramount for resource efficiency and environmental impact reduction. Additionally, global energyrelated carbon emissions from buildings equates to 39%, with 11% of this accounting for materials and construction of buildings. There is an immediate need to decarbonize the construction sector, and the implementation of circular economy can help to that. But theapplication is currently in its infancy. Successful adoption and implementation, therefore, remains an enormous global challenge. There is a need for businesses to develop effective strategies to overcome the significant barriers to ensure the circularity of materials.This paper aims to advance understanding of the needs and barriers associated with the implementation of a circular economy to aid in the decarbonization of the construction industry. A semi structured interview process was used to identify barriers and needs within the construction industry, with participants from different companies providing insights from their roles within construction and material use. The results of this study provide barriers to circular economy in construction and strategies required to overcome these barriers

    Application of autochthonous extremophilic Bacillus xiamenensis in remediation of groundwater- A sorption-based metal cleaning approach

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    Surface water and groundwater used for drinking and agricultural purposes are contaminated due to anthropogenic and geogenic activities. Escalated metal concentrations, xenobiotic pollutants, competitive ions, and reusability issues are hindrances to decontamination. Moreover, the expensive purification technology brings obstacles to the underdeveloped community from availing clean water. In this context, the present work offers a sustainable cost-effective approach by providing an effective and sustainable sorption-based purification method by novel polyextremophilic bacteria Bacillus xiamenensis ISIGRM16 isolated from metal-rich industrial waste, red mud. Batch adsorption study revealed that the bacterium can remove Cd2+(>99%), Ni2+(>85%), and Cr6+(>40%) from aqueous solution. The optimum parametric conditions for the removal of Cd2+ and Ni2+ were observed at a temperature of 30 °C and a pH of 6, while for Cr6+ removal, the optimal conditions were a temperature of 45 °C and a pH of 2. The adsorption process of Cd2+ was best explained by Freundlich isotherm (R2 ≥ 0.95), revealing multilayer adsorption. Ni2+ and Cr6+ followed the Langmuir isotherm, indicated adsorption onto the monolayer surface. The interaction mechanism was determined to be 2nd order kinetics, with both exothermic (Cd2+, Ni2+) and endothermic (Cr6+) characteristics. The maximum adsorption capacities were found to be 31.42, 29.30, and 15.21 mg g−1 for Cd2+, Ni2+, and Cr6+ respectively. In the ternary system, the adsorption capacity followed the order Ni2+ > Cd2+ > Cr6+, as confirmed by both their relative adsorption capacity and from analysis visual MINTEQ. Microscopic and spectroscopic analyses revealed, altered cell morphology, metal deposition on the bacterial cell surface, and the involvement of hydroxyl, carboxyl, and amide groups in the elimination of Cd2+, Ni2+, and Cr6+. Further the sequential adsorption-desorption study confirmed a significantly preserved removal efficacy (p < 0.05), indicating the advantageous use of the bacterium as a biosorbent

    Proposed New SD-WAN Architecture to Facilitate Dynamic Load Balancing

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    SD-WAN (Software Defined Wide Area Networking) is widely regarded as the future of networking as it integrates programmable features into its architecture. However, there is currently no all-encompassing solution for traffic monitoring policies in the control plane that accounts for the dynamic behaviour of applications transported in the SD-WAN architecture. In a traditional SD-WAN controller configuration, load balancing is distributed across different WANs according to predefined policies. Furthermore, existing SD-WAN controllers do not account for the effect of load balancing on end-to-end protocol performance and vice versa. To address this gap, this study proposes a new logical SD-WAN architecture to facilitate dynamic load balancing of end-to-end protocol operations in the SD-WAN architecture for improved resource utilisation. This is achieved through interaction between the Enhanced SD-WAN controller's traffic management decisions system and end-to-end protocol performance, which requires deep packet inspection of network data flows to detect signs of congestion. The solution involves developing a traffic monitor function which is responsible for analysing, classifying, and managing traffic. Additionally, an enhanced SD-WAN controller called “En-SDWAN controller” focuses on sending route updates to edge routers to change the route of traffic flows that are experiencing congestion is implemented. The performance of the developed Enhanced SD-WAN architecture was assessed in reference to the traditional SD-WAN across various scenarios, including regular traffic, link failure, and when network congestion is experienced. In the normal traffic conditions, the performance of Enhanced SD-WAN closely resembles that of traditional SD-WAN, owing to the absence of congestion within the network architecture. The average throughput performance of Enhanced SD-WAN stands at 50.07%, while traditional SD-WAN operates at 49.93%. However, during network link failures, Enhanced SD-WAN demonstrates quicker convergence and better throughput performance compared to traditional SD-WAN by 1.46%. Similarly, during instances of network congestion, Enhanced SD-WAN exhibits an average throughput of 11.21Mbps, surpassing traditional SD-WAN's average throughput of 7.02Mbps. The implementation of both the GNS3 and Python applications validates the results and design, demonstrating consistency throughout. This outcome underscores the improved flow control of packets facilitated by route updates and dynamic load sharing implemented within the Enhanced SD-WAN controller. The implementation of a new logical architecture has enhanced the performance and efficiency of traditional SD-WAN systems by adapting to the evolving nature of applications and offering better control over network traffic

    Additive manufacturing technology adoption in the upstream supply chain of the Nigerian oil and gas industry

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    Additive Manufacturing (AM) has grown in popularity and advancement in academic research and industrial application, and benefits to supply chain are well documented, yet the technology appears relatively new to Oil and Gas (O&G) sectors, especially in Nigeria. Dwindling price of oil and volatility, high cost of operation, high competition, environmental pollution, complexity of drilling and production processes are current challenges faced by the upstream sector of O&G industries for which AM adoption could add value to its operations and mitigate some of these challenges. However, AM has received little or no empirical research attention in Nigeria. This study explored AM technology adoption in the Nigerian Oil and Gas (O&G) industry upstream chain adopting a case study research strategy using four cases consisting of upstream supplier O&G companies. Data collection via semi-structured interviews and review of documents were analysed using qualitative content analysis. Cross-case analysis improved the transparency and consistency of themes emerging across the four case companies regarding AM adoption process found to be at an early stage in Nigeria with third-party adoption, and centralised mode at the international headquarters. Major findings were technological, organisational, and environmental enablers and barriers to adoption in O&G industries in Nigeria and perceived benefits of the adoption of AM technology were shortening the supply chain and reduction in inventory and logistics. Research design shaped development of a conceptual Model for Adoption of AM Technology in Nigerian O&G Industry supply chain extending theories and models and contributing to the body of scientific research. This study contributes knowledge to inform the adoption and practice of AM technology adoption in the O&G sector in Nigeria by reporting process and approaches and informing decision making. Exposition of the wide-ranging factors (technological, organisational, and environmental) facilitating and inhibiting AM adoption point to the need for collaborative approach in AM adoption for effective AM adoption in O&G upstream supply chain in Nigeria. The proposed model of adoption of AM technology in the O&G industry has implications for the creation of new areas in supply chain management as well as expansion in the engineering sector

    HLB Disease Detection in Omani Lime Trees Using Hyperspectral Imaging Based Techniques

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    In the recent years omani acid lime cultivation and production has been affected by Citrus greening or Huanglongbing (HLB) disease. HLB disease is one of the most destructive diseases for citrus with no remedies or countermeasures to stop the disease. Currently used Polymerase chain reaction (PCR) and Enzyme-linked immunosorbent assay (ELISA) HLB detection tests require lengthy and labor-intensive laboratory procedures. Furthermore, the equipment and staff needed to carry out the laboratory procedures are specialized hence making them a less optimal solution for the detection of the disease. The current research uses hyperspectral imaging technology for automatic detection of citrus trees with HLB disease. Omani citrus tree leaf images were captured through portable Specim IQ hyperspectral camera. The research considered healthy, nutrition deficient and HLB infected leaf samples based on the Polymerase chain reaction (PCR) test. The high-resolution image samples were sliced to into sub cubes. The sub cubes were further processed to obtain RGB images with spatial features. Similarly, RGB spectral slices were obtained through a moving window on the wavelength. The resized spectral-spatial RGB images were given to Convolution Neural Network for deep feature extraction. The current research was able to classify a given sample to the appropriate class with 92.86% accuracy indicating the effectiveness of the proposed techniques. The significant bands with a difference in three types of leaves are found to be 560 nm, 678 nm, 726 nm and 750 nm. This research offers a promising and effective approach utilizing cutting-edge technology to address the critical challenge of HLB disease in Omani citrus trees, providing a potential pathway for more efficient disease identification and management in the citrus industry


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