101 research outputs found

    Numerical investigations on the performance and emissions of a turbocharged engine using an ethanol-gasoline blend

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    Due to a scarcity of fossil fuel supplies and concerns about pollution, the use of ethanol in gasoline has become a priority in the automobile industry. This paper aims to investigate the effect of different ethanol-gasoline fuel blend ratios, namely E20 (% ethanol + % gasoline), E50 (% ethanol + % gasoline), and E75 (75% ethanol + 25% gasoline) on a 1.6 L turbocharged, 4-cylinder, 2017 Proton Preve Premium CFE CVT engine, where E0 (pure gasoline) is taken as reference fuel. In addition, different speed intervals, which include 1000 RPM, 2000 RPM, and 5000 RPM, are employed for each fuel blend. The production of four major emissions, NOx, CO, CO2, and HC, and performance parameters such as thermal efficiency, volumetric efficiency, and brake-specific fuel consumption, are evaluated using SolidWorks for CAD modelling. This then is transferred to ANSYS for emission and performance analysis. According to the findings, increasing ethanol concentration and engine speed increases volumetric efficiency and brake-specific fuel consumption by up to 12.89% and 6.59%, respectively. It was also discovered that ethanol and increasing engine speed had an 11.39% reduction in thermal efficiency. Furthermore, the addition of ethanol occurs, along with an increase in speed, exhaust gas emissions are reduced by up to 21.74% compared to pure gasoline

    One-Year Results of Simultaneous Topography-Guided Photorefractive Keratectomy and Corneal Collagen Cross-Linking in Keratoconus Utilizing a Modern Ablation Software

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    Purpose. To evaluate effectiveness of simultaneous topography-guided photorefractive keratectomy and corneal collagen cross-linking in mild and moderate keratoconus. Methods. Prospective nonrandomized interventional study including 20 eyes of 14 patients with grade 1-2 keratoconus that underwent topography-guided PRK using a Custom Ablation Transition Zone (CATz) profile with 0.02% MMC application immediately followed by standard 3 mw/cm2 UVA collagen cross-linking. Maximum ablation depth did not exceed 58 μm. Follow-up period: 12 months. Results. Progressive statistically significant improvement of UCVA from 0.83±0.37 logMAR preoperative, reaching 0.25±0.26 logMAR at 12 months (P<0.001). Preoperative BCVA (0.27±0.31 logMAR) showed a progressive improvement reaching 0.08±0.12 logMAR at 12 months (P=0.02). Mean Kmax reduced from 48.9±2.8 to 45.4±3.1 D at 12 months (P<0.001), mean Kmin reduced from 45.9±2.8 D to 44.1±3.2 D at 12 months (P<0.003), mean keratometric asymmetry reduced from 3.01±2.03 D to 1.25±1.2 D at 12 months (P<0.001). The safety index was 1.39 at 12 months and efficacy index 0.97 at 12 months. Conclusion. Combined topography-guided PRK and corneal collagen cross-linking are a safe and effective option in the management of mild and moderate keratoconus. Precis. To our knowledge, this is the first published study on the use of the CATz ablation system on the Nidek Quest excimer laser platform combined with conventional cross-linking in the management of mild keratoconus

    Towards Wind Energy-based Charging Stations: A Review of Optimization Methods

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    Due to the growing importance of renewable sources in sustainable energy systems, the strategic deployment of robust optimization techniques plays a crucial role in the design of Electric Vehicle Charging Stations (EVCSs). These stations need to smoothly incorporate renewable sources, ensuring optimal energy utilization. This study provides a comprehensive overview of the methodologies and approaches employed in the enhancement of wind energy based EVCSs. The aim is to discern the most efficacious techniques for optimizing charging stations. Researchers engage diverse strategies and methodologies in the realm of sizing and optimization, encompassing a spectrum of algorithmic implementations and software solutions. Evidently, each algorithm or software application bears distinctive merits and demerits. Singular reliance on a solitary algorithm or software for charging utility optimization is discerned to be potentially limiting. The investigation reveals that achieving better results in Electric Vehicle Charging Station (EVCS) optimization is facilitated by the collaborative use of multiple algorithms like GA, PSO, and ACO, among others, or software tools like Homer or RETScreen

    Review: Current trends in coral transplantation – an approach to preserve biodiversity

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    Ammar MSA,El-Gammal F, Nassar M, Belal A, Farag W, El-Mesiry G, El-Haddad K, Orabi A, Abdelreheem A, Shaaban A. 2013. Review: Current trends in coral transplantation – an approach to preserve biodiversity. Biodiversitas 14: 43-53. The increasing rates of coral mortality associated with the rise in stress factors and the lack of adequate recovery worldwide have urged recent calls for actions by the scientific, conservation, and reef management communities. This work reviews the current trends in coral transplantation. Transplantation of coral colonies or fragments, whether from aqua-, mariculture or harvesting from a healthy colony, has been the most frequently recommended action for increasing coral abundance on damaged or degraded reefs and for conserving listed or “at-risk” species. Phytoplanktons are important for providing transplanted corals with complex organic compounds through photosynthesis. Artificial surfaces like concrete blocks, wrecks or other purpose-designed structures can be introduced for larval settlement. New surfaces can also be created through electrolysis. Molecular biological tools can be used to select sites for rehabilitation by asexual recruits. Surface chemistry and possible inputs of toxic leachate from artificial substrates are considered as important factors affecting natural recruitment. Transplants should be carefully maintained , revisited and reattached at least weekly in the first month and at least fortnightly in the next three months. Studies on survivorship and the reproductive ability of transplanted coral fragments are important for coral reef restoration. A coral nursery may be considered as a pool for local species that supplies reef-managers with unlimited coral colonies for sustainable management. Transplanting corals for making artificial reefs can be useful for increasing biodiversity, providing tourist diving, fishing and surfing; creating new artisanal and commercial fishing opportunities, colonizing structures by fishes and invertebrates), saving large corals during the construction of a Liquified Natural Gas Plant

    Evaluation of baseline cleanliness of food contact surfaces in Basrah Governorate restaurants using ATP-bioluminescence to assess the effectiveness of HACCP application in Iraq

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    The Hazard Analysis and Critical Control Points (HACCP) system prevents and manages physical, chemical and biological risks at places where foods and beverages are processed, packaged, distributed and consumed. The present study (1) assessed the level of microbial contamination of food contact surfaces using adenosine triphosphate (ATP)-bioluminescence in Iraq restaurants; (2) investigated the level of microbial contamination of food contact surfaces; and (3) evaluated the efficiency of sanitizers in removing biological hazards from food contact surfaces. The ATP-bioluminescence discovered the presence of Escherichia coli and Staphylococcus aureus on surfaces and tools. Results also showed that the HACCP application was very effective in the amelioration of food quality

    Techno-economic analysis of a wind-energy-based charging station for electric vehicles in high-rise buildings in Malaysia

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    Renewable energy sources have become necessary for long-term energy sustainability due to the increased demand for electric cars and worrisome rises in carbon dioxide emissions from traditional energy sources. Furthermore, transportation is one of the sectors that uses the most energy on the planet, accounting for 24% of overall consumption. Fossil fuels are still the dominant energy source for balancing global demand/supply dynamics. Supporting laws and regulations have enhanced the first phase of environmentally friendly energy-resource consumption. This has spurred the development of new solutions that cut greenhouse-gas emissions and reduce the air pollution produced by internal combustion engines that are fuelled by fossil fuels. Wind energy is one of the clean energy sources that may be utilised for this purpose. Wind energy has been used to power electric-car-charging infrastructure, generally in a hybrid mode with another renewable source. This research examines the possibility of using wind energy as a standalone energy source to support electric-vehicle-charging infrastructure. Using data from Malacca, Malaysia, and HOMER software, the project will build and optimise a standalone wind-powered charging station. An RC-5K-A wind turbine coupled to a battery and converter is the appropriate choice for the system. The findings demonstrate that the turbine can produce 214,272 kWh per year at the cost of USD 0.081/kWh, confirming wind’s future feasibility as an energy-infrastructure support source

    The effect of value innovation in the superior performance and sustainable growth of telecommunications sector : Mediation effect of customer satisfaction and loyalty

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    The telecommunications industry has recognized innovation as the key to growth and survival. Globalization, liberalization, and privatization, the terms most commonly associated with this sector, have resulted in fierce competition, making it more difficult for telecommunications firms to increase their market share and, as a result, their customer base, sales volume, and, ultimately, profits. The new success strategy is differentiation through innovation, with the aim of breaking out of the competition and creating an uncontested market. This can be accomplished by providing high-value, innovative services that result in customer satisfaction and promote customer loyalty. The primary goal of this study was to create and validate a conceptual model of value innovation and its impact on firm performance and long-term growth by examining the mediation effect of customer satisfaction and loyalty. The empirical analysis results were based on 304 respondents who completed a paper-based survey provided to employees of Yemeni mobile service providers using a convenience non-probability sampling technique. SmartPLS 3 was used to test the hypothesized relationships using partial least squares structural equation modeling (PLS-PM). As a result, the findings empirically validated the theoretical research model, confirming the importance of the value innovation approach to achieving company performance and long-term growth by promoting customer satisfaction and loyalty. Finally, we have provided a discussion of the study’s theoretical contributions, managerial implications, and future research directions

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Effects of home confinement on mental health and lifestyle behaviours during the COVID-19 outbreak:insights from the ECLB-COVID19 multicentre study

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    Although recognised as effective measures to curb the spread of the COVID-19 outbreak, social distancing and self-isolation have been suggested to generate a burden throughout the population. To provide scientific data to help identify risk factors for the psychosocial strain during the COVID-19 outbreak, an international cross-disciplinary online survey was circulated in April 2020. This report outlines the mental, emotional and behavioural consequences of COVID-19 home confinement. The ECLB-COVID19 electronic survey was designed by a steering group of multidisciplinary scientists, following a structured review of the literature. The survey was uploaded and shared on the Google online survey platform and was promoted by thirty-five research organizations from Europe, North Africa, Western Asia and the Americas. Questions were presented in a differential format with questions related to responses “before” and “during” the confinement period. 1047 replies (54% women) from Western Asia (36%), North Africa (40%), Europe (21%) and other continents (3%) were analysed. The COVID-19 home confinement evoked a negative effect on mental wellbeing and emotional status (P < 0.001; 0.43 ≤ d ≤ 0.65) with a greater proportion of individuals experiencing psychosocial and emotional disorders (+10% to +16.5%). These psychosocial tolls were associated with unhealthy lifestyle behaviours with a greater proportion of individuals experiencing (i) physical (+15.2%) and social (+71.2%) inactivity, (ii) poor sleep quality (+12.8%), (iii) unhealthy diet behaviours (+10%), and (iv) unemployment (6%). Conversely, participants demonstrated a greater use (+15%) of technology during the confinement period. These findings elucidate the risk of psychosocial strain during the COVID-19 home confinement period and provide a clear remit for the urgent implementation of technology-based intervention to foster an Active and Healthy Confinement Lifestyle AHCL)
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