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Bond strength of the interface between concrete substrate and overlay concrete containing fly ash exposed to high temperature
No full textYesBond between substrate and overlay concretes is a key factor for the success of the repair method and significantly influences the structural performance of the repaired element. This study investigated the effect of fly ash and the surface preparation method on the bond strength of repaired concrete after exposure to high temperatures, that has not been comprehensively studied in the literature. For this purpose, overlay concretes containing 0, 5, 10, 15, and 20% fly ash as a replacement by weight of cement were cast on the original concrete surface prepared by four methods namely, as-cast, wire brushed, grooved and grooved-wire brushed. The bond strength of the interface between concrete substrate and overlay concrete was evaluated after exposure to 23, 200, 400, and 600oC temperatures for 1 hour. The results showed that partial replacement of cement by fly ash in the overlay concrete increased the bond strength of repaired concrete by up to 71%, depending on the amount of fly ash used, surface preparation method, and the temperature to which the sample was exposed. The maximum increase of bond strength was recorded for concrete containing 20% fly ash when the wire brushed preparation method was adopted at temperature of 200oC. However, surface preparation was the most influential parameter, achieving a bond strength gradual increase in order from as-cast, wire brushed, grooved to grooved-wire brushed methods. The results also showed that for most of the samples having similar surface preparation and the same percentage of fly ash, bond strength decreased with the increase of exposure to temperature; for example, for overlay concretes without fly ash, in as-cast and wire brushed surface preparation methods at temperatures of 400 and 600 oC, the bond strength has reached zero. On the other hand, for grooved and grooved-wire brushed surface preparation methods, the bond strength reduction was about 63%, when temperature increased from 23 to 600oC
A dynamic performance evaluation of distress prediction models
Get PDFYesSo far, the dominant comparative studies of competing distress prediction models (DPMs) have been restricted to the use of static evaluation frameworks and as such overlooked their performance over time. This study fills this gap by proposing a Malmquist Data Envelopment Analysis (DEA)-based multi-period performance evaluation framework for assessing competing static and dynamic statistical DPMs and using it to address a variety of research questions. Our findings suggest that (1) dynamic models developed under duration-dependent frameworks outperform both dynamic models developed under duration-independent frameworks and static models; (2) models fed with financial accounting (FA), market variables (MV), and macroeconomic information (MI) features outperform those fed with either MVMI or FA, regardless of the frameworks under which they are developed; (3) shorter training horizons seem to enhance the aggregate performance of both static and dynamic models
How privacy practices affect customer commitment in the sharing economy: A study of Airbnb through an institutional perspective
Get PDFYesPrivacy is an emerging issue for home-sharing platforms such as Airbnb. Home-sharing providers (business
customers) are subject to both digital privacy risks (e.g., data breaches and unauthorized data access) and
physical privacy risks (e.g., property damage and invasion of their personal space). Therefore, platforms need to
strengthen their institutions of privacy management to protect the interests of providers and maintain their
commitment. By applying the micro-level psychological aspect of institutional theory, our research investigates
how providers decide their level of commitment to a platform by evaluating the institutions of the platform’s
privacy management. Our survey recruited 380 Airbnb providers from the Prolific panel. Structural equation
modeling analysis shows that both physical and digital privacy practices strengthen providers’ legitimacy
judgment of the platform’s privacy management and subsequently increase their commitment to the platform.
Our theoretical contribution lies in revealing the effects of physical and digital privacy practices on B2B relationships from an institutional perspective. Our research is among the first to provide an integrative framework
illustrating providers’ psychological process of legitimacy judgement. It also has practical implications for
sharing economy platforms to manage privacy.The authors gratefully acknowledge the Seed Corn Funding from University of Bradford and the Research Productivity Support Scheme from Macquarie University
Kinship practices in Early Iron Age southeast Europe: genetic and isotopic analysis of burials from the Dolge njive barrow cemetery, Dolenjska, Slovenia
Get PDFYesDNA analysis demonstrates that all seven individuals buried in an Early Iron Age barrow at Dolge njive, southeast Slovenia, are close biological relatives. Although group composition does not suggest strict adherence to a patrilineal or matrilineal kinship system, the funerary tradition appears highly gendered, with family links through both the male and female line being important in structuring communities. We explore the implications for our understandings of kinship and funerary practices in Early Iron Age southeast Europe.European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 291827; HERA Joint Research Programme which is co-funded by AHRC, AKA, BMBF via PT-DLR, DASTI, ETAG, FCT, FNR, FNRS, FWF, FWO, HAZU, IRC, LMT, MHEST, NWO, NCN, RANNÍS, RCN, VR and The European Community FP7 2007-2013, under the Socioeconomic Sciences and Humanities programme; European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 834087 (COMMIOS). NIH grant GM100233, John Templeton Foundation grant 61220, the Howard Hughes Medical Institute, and the Allen Discovery Center program, a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation
Healthcare workers' perceptions on diabetic foot ulcers (DFU) and foot care in Fiji: a qualitative study
Get PDFYesTo explore the perception of healthcare workers (HCWs) on diabetic foot ulcers (DFU) and foot care in Rotuma, Fiji.
Using a qualitative study design, two focus group discussions (FGDs) were conducted among HCWs. A semistructured open-ended questionnaire was used to guide the discussion session. Each FGD was audiorecorded and was transcribed. The transcriptions were then manually analysed using thematic analysis.
Rotuma hospital, Fiji.
HCWs who were working in Rotuma hospital for at least a year and were involved in clinical foot care of type 2 diabetes mellitus patients were included.
There were five main themes, namely, depth of knowledge, quality of care in practice, factors of influence on practice, lack of resources and capacity building. Participants had superficial knowledge that showed lack of in-depth scientific knowledge. A lack of staffing in the clinics affected the delivery of service. Additionally, patients defaulting clinics, late presentations with DFU and traditional medicine also affected the quality of healthcare service in clinics. There was also a need for a multidisciplinary team to prevent and manage DFU. HCWs mostly advised on glycaemic control and ignored offering foot care advice in clinics due mainly to the lack of sound knowledge on foot care. There was also a lack of resources, infrastructure, space and professional development opportunities, which negatively impacted how HCWs deliver foot care services to patients.
HCWs lack significant in-depth knowledge on DFU and foot care. In addition, these are the availability of traditional medicine that delays presentations to hospital, further reducing the quality of services. HCWs need to keep their knowledge and skills updated through regular in-service training on foot care. Resources, infrastructure and supply chains need to be maintained by those in power to ensure HCWs deliver quality foot care services
Knowledge for a warmer world: A patent analysis of climate change adaptation technologies
Get PDFYesTechnologies can help strengthen the resilience of our economy against existential climate-risks. We investigate
climate change adaptation technologies (CCATs) in US patents to understand (1) historical patterns and possible
drivers of innovation; (2) scientific and technological requirements to develop and use CCATs; and (3) CCATs’
potential technological synergies with mitigation. First, in contrast to mitigation, innovation in CCATs only
slowly takes off, indicating a relatively low awareness of investors for solutions to cope with climate risks.
We discuss how historical trends in environmental regulation, energy prices, and public support may have
contributed to patenting in CCATs. Second, CCATs form two main clusters: science-intensive ones in agriculture,
health, and monitoring technologies; and engineering-intensive ones in coastal, water, and infrastructure
technologies. Analyses of technology-specific scientific and technological knowledge bases inform directions
for how to facilitate advancement, transfer and use of CCATs. Lastly, CCATs show strong technological
complementarities with mitigation as more than 25% of CCATs bear mitigation benefits. While not judging
about the complementarity of mitigation and adaptation in general, our results suggest how policymakers can
harness these technological synergies to achieve both goals simultaneously
Why do small businesses have difficulty in accessing bank financing?
Get PDFYesThis study investigates bank financing to small and medium-size enterprises (SMEs) and evaluates whether the difficulties of SMEs in accessing bank financing during a period of financial crisis are due to a reduction in the supply of credit, or to a decrease in the demand for credit. The results show that the macroeconomic setting matters: demand effects are unlikely to drive the decline in the stock of bank loans, while the supply of credit causes SMEs difficulties in accessing bank credit. During a crisis period, in particular, an increase in the risk of lenders leads to the reduced supply of credit and credit rationing (i.e. the bank lending channel). In a post-crisis period, SMEs with increased risk and decreased profits have great difficulties in securing bank loans (i.e. the borrower balance sheet channel). Taken together, these results suggest that supply effects initially emerge through the bank-lending channel and then shift to the borrower balance sheet channel over a period of financial crisis
Model-based generation of manufacturing process plans through incremental topology formation
No full textYesIn advanced manufacturing systems, the production of complex and highly customisable products requires the preparation of many different product specifications and associated manufacturing process plans. The creation of these plans involves the search for the production resources (e.g. robots, machine tools, inspection devices) that are needed to implement the product specifications and how to orchestrate them. We present a model-based approach to the automatic generation of manufacturing process plans from the models of the target products and available resources. The modelling language is based on labelled transition systems, which are useful to represent sequences of operations that can be executed in parallel by multiple production resources. Some preliminary experimental results demonstrate the feasibility of the presented approach
Fabrication of AA6061/316 composites via a double pin FSP tool
Get PDFYesIn this study, a new double pin tool was utilized for the development of AA6061/316 stainless steel reinforced composite by employing the friction stir processing technique for the first time. The microstructure, hardness, tensile, tribological, and corrosion behaviors of the fabricated composites were investigated and comparative assessments were made with the results obtained from the single-pin tool. The results showed that particle-matrix reaction did not occur in the composites irrespective of the nature of the tool profile. The double-pin tool outstandingly boosted the grain refinement (7.01-5.78 μm), particle fragmentation, and distribution within the Al matrix due to the additional pin-assisted plastic deformation, high straining, dynamic recrystallization, and Zener pinning effects. The double-pin tool improved the microhardness (127-141 HV), tensile strength (162-233 MPa), and corrosion resistance of the composite with respect to the single-pin tool counterparts. The replacement of the single pin tool with a double pin tool diminished the specific wear rate (0.38-0.22 mm3/Nm) of the composite. The double-pin tool has a favourable impact on the structure, mechanical, and corrosion behaviours of the AA6061/316 stainless steel reinforced composite. It is thus recommended for composite development
Evaluation of solar energy powered seawater desalination pro-cesses: A review
Get PDFYesSolar energy, amongst all renewable energies, has attracted inexhaustible attention all over the world as a supplier of sustainable energy. The energy requirement of major seawater desalination processes such as multistage flash (MSF), multi-effect distillation (MED) and reverse osmosis (RO) are fulfilled by burning fossil fuels, which impact the environment significantly due to the emission of greenhouse gases. The integration of solar energy systems into seawater desalination processes is an attractive and alternative solution to fossil fuels. This study aims to (i) assess the progress of solar energy systems including concentrated solar power (CSP) and photovoltaic (PV) to power both thermal and membrane seawater desalination processes including MSF, MED, and RO and (ii) evaluate the economic considerations and associated challenges with recommendations for further improvements. Thus, several studies on a different combination of seawater desalination processes of solar energy systems are reviewed and analysed concerning specific energy consumption and freshwater production cost. It is observed that although solar energy systems have the potential of reducing carbon footprint significantly, the cost of water production still favours the use of fossil fuels. Further research and development on solar energy systems are required to make their use in desalination economically viable. Alternatively, the carbon tax on the use of fossil fuels may persuade desalination industries to adopt renewable energy such as solar.Solar energy, amongst all renewable energies, has attracted inexhaustible attention all over the world as a supplier of sustainable energy. The energy requirement of major seawater desalination processes such as multistage flash (MSF), multi-effect distillation (MED) and reverse osmosis (RO) are fulfilled by burning fossil fuels, which impact the environment significantly due to the emission of greenhouse gases. The integration of solar energy systems into seawater desalination processes is an attractive and alternative solution to fossil fuels. This study aims to (i) assess the progress of solar energy systems including concentrated solar power (CSP) and photovoltaic (PV) to power both thermal and membrane seawater desalination processes including MSF, MED, and RO and (ii) evaluate the economic considerations and associated challenges with recommendations for further improvements. Thus, several studies on a different combination of seawater desalination processes of solar energy systems are reviewed and analysed concerning specific energy consumption and freshwater production cost. It is observed that although solar energy systems have the potential of reducing carbon footprint significantly, the cost of water production still favours the use of fossil fuels. Further research and development on solar energy systems are required to make their use in desalination economically viable. Alternatively, the carbon tax on the use of fossil fuels may persuade desalination industries to adopt renewable energy such as solar