85000 research outputs found
Sort by
A nanofluid-based hybrid photovoltaic-thermal -thermoelectric generator system for combined heat and power applications
No full texthis study investigates the use of nanofluid-cooled Thermoelectric Generators (TEGs) integrated with a Photovoltaic (PV) panel to enhance the overall energy efficiency of the system. Three cooling fluids — Water (W), CuO/W single Nanofluid (NF), and CuO-Fe/W hybrid NF — are examined at various flow rates for cooling the PV panel. The research studies the PVT-TEG-NF system considering both normal and concentrated solar irradiation in a 3D parallelly-cooled heat sink setup and comparing its electrical and thermal performance, which has not been previously addressed in the literature. The results demonstrate that by utilizing CuO-Fe/W, the PV temperature at irradiation of 935 W/m2 in the summer can be maintained at 31.7 °C, which is 8.8 % and 13 % lower than those achieved by using CuO/W and water, respectively. For 0.08 m/s of CuO-Fe/W inlet velocity, the total output power PV-TEG is about 9.5 W, with a heat removal rate of ∼37.2 W. Additionally, by utilizing the CuO-Fe/W compared to water, the combined efficiency of the system (the ratio of electrical and thermal power output to solar input) increases from 66.7 % to 76.7 %. In the second part, the study introduces a new approach to maintain a steady PV efficiency while increasing solar concentration by adjusting the cooling fluid flow rate. By increasing solar concentration from 1.5 suns to 2.5 suns, the PV temperatures could be maintained at 44.5 °C and 51.5 °C using CuO-Fe/W and water with 0.12 m/s of inlet velocity, respectively. This made it possible to enhance the power output of the PV and TEGs by 65.9 % and 187 %, respectively, by using CuO-Fe/W as coolant, while the temperature of the panel could be maintained at a safe level
Crushing performance of bioinspired hierarchical tapered structures
No full textThis paper introduces a new type of energy-absorbing hierarchical tapered structure, mimicking the hierarchical architecture of barnacle. The proposed structures are designed by iteratively incorporating sub-tapered tubes at the junctions of primary ribs aiming to enhance the crashworthiness performance. The finite element models of the proposed structures are constructed in Abaqus software and validated using experimental testing. The effects of the geometrical parameters including the number of substructures and the external-to-internal wall thickness ratio on the energy absorption characteristics of the proposed structures are investigated. The results demonstrate that as the number of substructures increases, the specific energy absorption (SEA) and mean crushing force of the proposed design show a significant improvement. Specially, the SEA of the proposed structures with four substructures can reach 32.78 kJ/kg, which is 85.8 % higher than the conventional tapered tube. Additionally, decreasing the ratio of external to internal wall thickness leads to enhanced performance. After optimizing the wall thickness ratio, the maximum SEA can reach 40.87 kJ/kg, which is 26.0 % higher than that before optimization. To complement the findings, a theoretical study is presented, which exhibits excellent agreement with the numerical results, further validating the effectiveness of the proposed design. This study highlights the potential of incorporating hierarchical and tapered features into tapered structures, offering promising prospects for advancements in energy absorption technology across diverse industries
TLR9 Monotherapy in Immune-Competent Mice Suppresses Orthotopic Prostate Tumor Development
No full textProstate cancer is ranked second in the world for cancer-related deaths in men, highlighting the lack of effective therapies for advanced-stage disease. Toll-like receptors (TLRs) and immunity have a direct role in prostate cancer pathogenesis, but TLR9 has been reported to contribute to both the progression and inhibition of prostate tumorigenesis. To further understand this apparent disparity, we have investigated the effect of TLR9 stimulation on prostate cancer progression in an immune-competent, syngeneic orthotopic mouse model of prostate cancer. Here, we utilized the class B synthetic agonist CPG-1668 to provoke a TLR9-mediated systemic immune response and demonstrate a significant impairment of prostate tumorigenesis. Untreated tumors contained a high abundance of immune-cell infiltrates. However, pharmacological activation of TLR9 resulted in smaller tumors containing significantly fewer M1 macrophages and T cells. TLR9 stimulation of tumor cells in vitro had no effect on cell viability or its downstream transcriptional targets, whereas stimulation in macrophages suppressed cancer cell growth via type I IFN. This suggests that the antitumorigenic effects of CPG-1668 were predominantly mediated by an antitumor immune response. This study demonstrated that systemic TLR9 stimulation negatively regulates prostate cancer tumorigenesis and highlights TLR9 agonists as a useful therapeutic for the treatment of prostate cancer
Thermally reversible prototype adhesive via the furan–maleimide Diels–Alder reaction
No full textThe development of structural epoxy adhesives with the capacity to bond and de-bond on-demand would open many opportunities for the assembly, inspection, repair, and end of life disposal of structural bonded assemblies. Herein, a reversible cross-linking mechanism enabling bonding and debonding of an epoxy adhesive based on Diels–Alder (DA) chemistry is investigated and demonstrated. The Diels–Alder incorporated multifunctional diamine cross-linker was initially synthesised, followed by forming a covalently cross-linked network with DGEBA epoxy at low temperature (80 °C) that breaks via cleavage of DA adducts at elevated temperature (150 °C). Upon cooling the covalent cross-links reform enabling the epoxy to retain adhesive properties, and the bonding/de-bonding effect was performed over two complete cycles advancing a thermally reversible adhesive based on the retro-DA mechanism. The viscoelastic properties of the prototype adhesive including viscosity, storage and loss modulus were retained after bonding and de-bonding cycles, affirming retro-DA reaction occurs at about 150 °C upon heating cycle and DA reaction upon cooling cycle. Mechanical testing demonstrates maximum of 39.5% reduction in bond strength in debonding cycle, followed by maximum of 100% bond strength in re-bonding cycle with no additional application of the prototype adhesive, revealing excellent adhesive performance
Orthorexia nervosa versus healthy orthorexia: Anxiety, perfectionism, and mindfulness as risk and preventative factors of distress
No full textBackground: Orthorexia nervosa is a recently conceptualised pathological entity presenting as an obsessive focus on healthy eating with associated psychosocial impairment. Aims: The present study investigated the differential associations between orthorexia nervosa and healthy orthorexia with distress and impairment. Materials & Methods: With a community sample (N = 268) multiple measures of orthorexia nervosa and health orthorexia were compared as explanatory variables in mediation structural equation modelling (SEM). Outcome variables assessed and investigated were psychological distress while demographic variables were controlled. The mediating roles of perfectionism and health anxiety on orthorexia nervosa were examined with further preventative mediation role of mindfulness on distress. Results: Distinctive to other eating disorders, gender showed no significant effects on orthorexia nervosa and healthy orthorexia. Signalling measurement issues for this disorder, the different measures of orthorexia nervosa resulted in mixed findings regarding body mass index and age. Findings supported perfectionism and health anxiety as risk factors, as well as mindfulness acceptance as a preventative factor in both orthorexia nervosa and healthy orthorexia. Orthorexia nervosa and healthy orthorexia assessed by most measures, contrary to the expectations, had significant positive associations with psychological distress indicated by stress, anxiety, and depression. Discussion & Conclusion: The complexity in differentiating orthorexia nervosa from healthy orthorexia calls for further investigation. This research effort should serve to substantiate the status of orthorexia nervosa as a distinct clinical disorder
Renal-protective effects of Chinese medicinal herbs and compounds for diabetic kidney disease in animal models: protocol for systematic review and meta-analysis
No full textBackground: Diabetic kidney disease (DKD) is a common and severe complication of diabetes that can lead to end-stage renal disease with no cure. The first-line drugs recommended by clinical guidelines fail to achieve satisfactory effects for people with DKD. A Chinese herbal medicine Tangshen Qushi Formula (TQF) shows preliminary efficacy and safety in preserving renal function for people with DKD, but the effects on comprehensive renal outcomes remain unclear. We will conduct a systematic review and meta-analysis to evaluate the effects of TQF herbs and their compounds identified from ultra-high performance liquid chromatography-MS/MS in diabetic animal models with renal outcomes. Methods: This protocol complies with the guideline Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. We will include studies investigating the effects of TQF herbs and compounds on diabetic rats or mice with renal outcomes. Six electronic databases will be searched from their inception to February 2023. Quality assessment will be conducted using SYRCLE’s risk of bias tool. Standardized or weighted mean differences will be estimated for renal outcomes (creatinine, urea, proteinuria, histological changes, oxidative stress, inflammation, and kidney fibrosis). Data will be pooled using random-effects models. Heterogeneity across studies will be expressed as I 2. Sensitivity analyses will explore treatment effects in adjusted models and within subgroups. Funnel plots and Egger’s test will be used to explore publication bias. Discussion: The results of this review will provide valuable insights into the potential effects of TQF in managing DKD. The limitation is that the included studies will be animal studies from specific databases, and the interpretation of the findings must be cautious. Systematic review registration: PROSPERO CRD42023432895. Registered on 19 July 2023 (https://www.crd.york.ac.uk/PROSPERO/#recordDetails)
Load distribution factors for quick design and assessment in typical Australian bridges
No full textThe increase in freight productivity in Australia is pressuring Australian bridge infrastructure. Bridge assessment is crucial to ensure the safety of bridges to accommodate heavier vehicles. Load distribution factor (LDF) has been widely used for bridge design and evaluation in the preliminary stage, but it is not specified in the Australian standard code. This study aims to develop the LDFs for typical Australian bridges with the most adverse load effects of single- and two-lane loads. Later, the LDFs were compared with the LDF equations in the different standards, including National Association of Australian State Road Authorities (National Association of Australian State Road Authorities, 1976), American Association of Highway and Transportation Officials: Load and Resistance Factor Design (AASHTO (2017), Henry’s and modified Henry’s methods. It can be concluded that the AASHTO (2017) LDF equations provide very good correlations with typical Australian bridges. It is possible to use the AASHTO LRFD LDF equations for assessing and designing in Australian concrete I-girder and Super-T girder bridges. However, most AASHTO LFRD provides conservative results of LDFs compared with LDFs of Australian bridges. It is recommended that LDFs of Australian bridges should be developed for bridge design and assessment
Corporate social responsibility and dividend payout policy in extraordinary time: Empirical study of South Africa
No full textCorporate social responsibility (CSR) is a strategic tool that firms use to gain competitive advantage and enhance profitability in the long run, yet its effect on dividend payout in extraordinary times is limited. Grounded in stakeholder and dual responsibility theories, this study examines the effect of CSR on the relationship between COVID-19 and dividend payout. Data from the period 2015–2021 were obtained from 114 non-financial listed firms on the Johannesburg Stock Exchange, South Africa, and analyzed by multivariate and logit regression techniques. COVID-19 has a negative effect on the amount and likelihood of dividend payment, while CSR performance has a positive effect on the likelihood and amount of dividend payment. However, the result of the negative effect of COVID-19 on dividend payment does not differ between high and low CSR performing firms. Conversely, the impact of COVID-19 and CSR on dividend payment differ between high and low financial constraint firms. Shareholders should learn to manage their expectations of dividends payment during times of crisis like COVID-19, as firms tend to focus more on addressing the needs of stakeholders through CSR initiatives, which will enhance profit in the long term, rather than paying out dividend to shareholders
Active Transport
No full textThis chapter examines regulatory options to maximise the contribution that active transport modes of cycling and walking can make towards deep decarbonisation in Australia. While not identified as an issue for the Deep Decarbonisation Pathways Project, active transport plays a pivotal role in deep decarbonisation by providing a modal shift for the short trips currently carried out by passenger vehicles and displacing some of the greenhouse gas emissions that arise from Australia’s transport sector annually, by greatly increasing energy efficiency and replacing fossil fuel transport modes with bio energy and renewables.
11.2 The chapter outlines several legal issues that contribute to the regulatory barriers in law, design and road safety, that together impede better uptake of cycling and walking as a mode of transport for short trips. Regulations that address the appropriate design of bicycles as vehicles, and road user behaviour and road design for bicycles and scooters, across disciplines of law, design, and road safety provide both scope and opportunity to create a more effective legal pathway to maximise the contribution that active transport can make to deep decarbonisation in Australia
Disasters and Recovery: Postcolonializing Economic Geography
No full textIn this chapter, I argue that postcolonial theory will enable economic geographers to reinterpret and reimagine disaster recovery as a process that is not the sole responsibility of the state, and which cannot be gauged by statistically measuring the health of the economy. A postcolonial methodology offers a solid historicization of disaster contexts and how the need to adapt and be resilient among marginalized people across the world has its origins in their placation, exploitation and colonization. Postcolonial thinking can provide economic geographers with the methodology to unearth how anti-colonial and normative forms of societal and economic organization may rupture from disasters at the grassroots level. Therefore, adopting a postcolonial methodology in disaster contexts is not merely about trying to understand how a society recovers or moving beyond simple statistical measurements of the economy. It is also about exposing and thinking critically about alternative futures that take seek to address the structures that (re)produce the vulnerabilities that predicate disasters