Search results for: solar gains

Authors: Che Hsiu Chen, Kuo Wei Tseng, Zih Jian Huang, Hon Wen Cheng

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A typical warm-up contains both stretching exercises and jogging. The static stretching prior to training or competition may cause detrimental effects to athletic performance. However, it is unclear whether different types of dynamic stretching exercises had different acute effects on knee flexors stiffness, flexibility, and strength. The purpose of this study was to analyze the knee flexors stiffness, flexibility, and strength gains after dynamic straight leg raise (DSLR) and dynamic modified toe-touch (MTT) stretching. Sixteen healthy university active men (height 176.27 ± 4.03 cm; weight 72.27 ± 8.90 kg; age 22.09 ± 2.31 years). After 5 minutes (8km/h) of running subjects performed 2 randomly ordered stretching protocols: DSLR and MTT stretching protocols. There were a total of six, 30 seconds bouts of dynamic stretching (15 repetitions) with 30seconds rest between bouts. The outcome measures were maximal voluntary isokinetic concentric hamstring strength (60°/s), muscle flexibility test by passive straight leg raise (PSLR), active straight leg raise (ASLR), and muscle stiffness using ultrasound Acoustic Radiation Forced Impulse (ARFI) elastography before and immediately after stretching. The muscle stiffness and concentric strength decreased significantly (p < .05), the flexibility no significant change after DSLR protocol (p > .05). The concentric strength decreased significantly (p < .05), the flexibility and muscle stiffness no significant change after MTT protocol (p > .05), whereas no significant differences were found for the DSLR and MTT. Our findings suggest that dynamic stretching (30s x 6 bouts) resulted in change in muscle stiffness or may be induced slack in the musculotendinous unit thereby, reducing force production. Therefore, 30s x 6 bouts of dynamic stretching adversely affects efforts of hamstring muscle maximal concentric strength.

Keywords: sport injury, ultrasound, eccentric exercise, performance

Procedia PDF Downloads 267

Authors: Asegid Belay Kebede, Getachew Biru Worku

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The Earth and its inhabitants have faced an existential threat as a result of severe manmade actions. Global warming and climate change have been the most apparent manifestations of this threat throughout the world, with increasingly intense heat waves, temperature rises, flooding, sea-level rise, ice sheet melting, and so on. One of the major contributors to this disaster is the ever-increasing production and consumption of energy, which is still primarily fossil-based and emits billions of tons of hazardous GHG. The transportation industry is recognized as the biggest actor in terms of emissions, accounting for 24% of direct CO2 emissions and being one of the few worldwide sectors where CO2 emissions are still growing. Rail transportation, which includes all from light rail transit to high-speed rail services, is regarded as one of the most efficient modes of transportation, accounting for 9% of total passenger travel and 7% of total freight transit. Nonetheless, there is still room for improvement in the transportation sector, which might be done by incorporating alternative and/or renewable energy sources. As a result of these rapidly changing global energy situations and rapidly dwindling fossil fuel supplies, we were driven to analyze the possibility of renewable energy sources for traction applications. Even a small achievement in energy conservation or harnessing might significantly influence the total railway system and have the potential to transform the railway sector like never before. As a result, the paper begins by assessing the potential for photovoltaic (PV) power generation on train rooftops and existing infrastructure such as railway depots, passenger stations, traction substation rooftops, and accessible land along rail lines. As a result, a method based on a Google Earth system (using Helioscopes software) is developed to assess the PV potential along rail lines and on train station roofs. As an example, the Addis Ababa light rail transit system (AA-LRTS) is utilized. The case study examines the electricity-generating potential and economic performance of photovoltaics installed on AALRTS. As a consequence, the overall capacity of solar systems on all stations, including train rooftops, reaches 72.6 MWh per day, with an annual power output of 10.6 GWh. Throughout a 25-year lifespan, the overall CO2 emission reduction and total profit from PV-AA-LRTS can reach 180,000 tons and 892 million Ethiopian birrs, respectively. The PV-AA-LRTS has a 200% return on investment. All PV stations have a payback time of less than 13 years, and the price of solar-generated power is less than $0.08/kWh, which can compete with the benchmark price of coal-fired electricity. Our findings indicate that PV-AA-LRTS has tremendous potential, with both energy and economic advantages.

Keywords: sustainable development, global warming, energy crisis, photovoltaic energy conversion, techno-economic analysis, transportation system, light rail transit

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Authors: Ramesh P., Aby Joseph

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Micro Inverters provide Module Embedded Solution for harvesting energy from small-scale solar photovoltaic (PV) panels. In addition to higher modularity & reliability (25 years of life), the MicroInverter has inherent advantages such as avoidance of long DC cables, eliminates module mismatch losses, minimizes partial shading effect, improves safety and flexibility in installations etc. Due to the above-stated benefits, the renewable energy technology with Solar Photovoltaic (PV) Micro Inverter becomes more widespread in Village Nano Grid application ensuring grid independence for rural communities and areas without access to electricity. While the primary objective of this paper is to discuss the problems related to rural electrification, this concept can also be extended to urban installation with grid connectivity. This work presents a comprehensive analysis of the power circuit design, control methodologies and prototyping of 300Wₚ Single Phase PV Micro Inverter. This paper investigates two different topologies for PV Micro Inverters, based on the first hand on Single Stage Flyback/ Forward PV Micro-Inverter configuration and the other hand on the Double stage configuration including DC-DC converter, H bridge DC-AC Inverter. This work covers Power Decoupling techniques to reduce the input filter capacitor size to buffer double line (100 Hz) ripple energy and eliminates the use of electrolytic capacitors. The propagation of the double line oscillation reflected back to PV module will affect the Maximum Power Point Tracking (MPPT) performance. Also, the grid current will be distorted. To mitigate this issue, an independent MPPT control algorithm is developed in this work to reject the propagation of this double line ripple oscillation to PV side to improve the MPPT performance and grid side to improve current quality. Here, the power hardware topology accepts wide input voltage variation and consists of suitably rated MOSFET switches, Galvanically Isolated gate drivers, high-frequency magnetics and Film capacitors with a long lifespan. The digital controller hardware platform inbuilt with the external peripheral interface is developed using floating point microcontroller TMS320F2806x from Texas Instruments. The firmware governing the operation of the PV Micro Inverter is written in C language and was developed using code composer studio Integrated Development Environment (IDE). In this work, the prototype hardware for the Single Phase Photovoltaic Micro Inverter with Double stage configuration was developed and the comparative analysis between the above mentioned configurations with experimental results will be presented.

Keywords: double line oscillation, micro inverter, MPPT, nano grid, power decoupling

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Authors: M. A. Amezcua-Allieri, E. Torres, J. A. Zermeño Eguía-Lis, M. Magdaleno, L. A. Melgarejo, E. Palmerín, A. Rosas, D. López, J. Aburto

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The use of biomass to produce renewable energy is one of the forms that can be used to reduce the impact of energy production. Like any other energy resource, there are limitations for biomass use, and it must compete not only with fossil fuels but also with other renewable energy sources such as solar or wind energy. Combustion is currently the most efficient and widely used waste-to-energy process, in the areas where direct use of biomass is possible, without the need to make large transfers of raw material. Many industrial facilities can use agricultural or forestry waste, straw, chips, bagasse, etc. in their thermal systems without making major transformations or adjustments in the feeding to the ovens, making this waste an attractive and cost-effective option in terms of availability, access, and costs. In spite of the facilities and benefits, the environmental reasons (emission of gases and particulate material) are decisive for its use for energy purpose. This paper describes a valorization of residues from forest industry to generate energy, using a case study.

Keywords: bioenergy, forest waste, life-cycle assessment, waste-to-energy, electricity

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Authors: Same Noel Ngando, Yakub Abdulfatai Olatunji

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Renewable energy micro-grids, such as those powered by solar or wind energy, are often intermittent in nature. This means that the amount of energy generated by these systems can vary depending on weather conditions or other factors, which can make it difficult to ensure a steady supply of power. To address this issue, energy storage systems have been developed to increase the reliability of renewable energy micro-grids. Battery systems have been the dominant energy storage technology for renewable energy micro-grids. Batteries can store large amounts of energy in a relatively small and compact package, making them easy to install and maintain in a micro-grid setting. Additionally, batteries can be quickly charged and discharged, allowing them to respond quickly to changes in energy demand. However, the process involved in recycling batteries is quite costly and difficult. An alternative energy storage system that is gaining popularity is hydrogen storage. Hydrogen is a versatile energy carrier that can be produced from renewable energy sources such as solar or wind. It can be stored in large quantities at low cost, making it suitable for long-distance mass storage. Unlike batteries, hydrogen does not degrade over time, so it can be stored for extended periods without the need for frequent maintenance or replacement, allowing it to be used as a backup power source when the micro-grid is not generating enough energy to meet demand. When hydrogen is needed, it can be converted back into electricity through a fuel cell. Energy consumption data is got from a particular residential area in Daegu, South Korea, and the data is processed and analyzed. From the analysis, the total energy demand is calculated, and different hybrid energy system configurations are designed using HOMER Pro (Hybrid Optimization for Multiple Energy Resources) and MATLAB software. A techno-economic and environmental comparison and life cycle assessment (LCA) of the different configurations using battery and hydrogen as storage systems are carried out. The various scenarios included PV-hydrogen-grid system, PV-hydrogen-grid-wind, PV-hydrogen-grid-biomass, PV-hydrogen-wind, PV-hydrogen-biomass, biomass-hydrogen, wind-hydrogen, PV-battery-grid-wind, PV- battery -grid-biomass, PV- battery -wind, PV- battery -biomass, and biomass- battery. From the analysis, the least cost system for the location was the PV-hydrogen-grid system, with a net present cost of about USD 9,529,161. Even though all scenarios were environmentally friendly, taking into account the recycling cost and pollution involved in battery systems, all systems with hydrogen as a storage system produced better results. In conclusion, hydrogen is becoming a very prominent energy storage solution for renewable energy micro-grids. It is easier to store compared with electric power, so it is suitable for long-distance mass storage. Hydrogen storage systems have several advantages over battery systems, including flexibility, long-term stability, and low environmental impact. The cost of hydrogen storage is still relatively high, but it is expected to decrease as more hydrogen production, and storage infrastructure is built. With the growing focus on renewable energy and the need to reduce greenhouse gas emissions, hydrogen is expected to play an increasingly important role in the energy storage landscape.

Keywords: renewable energy systems, microgrid, hydrogen production, energy storage systems

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Authors: H. M. Farghally, N. M. Ahmed, H. T. El-Madany, D. M. Atia, F. H. Fahmy

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Energy is required in almost every aspect of human activities and development of any nation in this world. Increasing fossil fuel price, energy security and climate change have important bearings on sustainable development of any nation. The renewable energy technology is considered one of the drastic approaches taken over the world to reduce the energy problem. The preservation of vegetables by freezing is one of the most important methods of retaining quality in agricultural products over long-term storage periods. Freezing factories show high demand of energy for both heat and electricity; the hybrid Photovoltaic/Thermal (PV/T) systems could be used in order to meet this requirement. This paper presents PV/T system design for freezing factory. Also, the complete mathematical modeling and Matlab Simulink of PV/T collector is introduced. The sensitivity analysis for the manufacturing parameters of PV/T collector is carried out to study their effect on the thermal and electrical efficiency.

Keywords: renewable energy, hybrid PV/T system, sensitivity analysis, ecological sciences

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Authors: Hussain Ali Bekhet, Nor Hamisham Harun

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The main objective of this paper is to give a comprehensive review of non-renewable energy and renewable energy utilization in Malaysia, including hydropower, solar photovoltaic, biomass and biogas technologies. Malaysia mainly depends on non-renewable energy (natural gas, coal and crude oil) for electricity generation. Therefore, this paper provides a comprehensive review of the energy sector and discusses diversification of electricity generation as a strategy for providing sustainable energy in Malaysia. Energy policies and strategies to protect the non-renewable energy utilization also are highlighted, focusing in the different sources of energy available for high and sustained economic growth. Emphasis is also placed on a discussion of the role of renewable energy as an alternative source for the increase of electricity supply security. It is now evident that to achieve sustainable development through renewable energy, energy policies and strategies have to be well designed and supported by the government, industries (firms), and individual or community participation. The hope is to create a positive impact on sustainable development through renewable sources for current and future generations.

Keywords: Malaysia, non-renewable energy, renewable energy, sustainable energy

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Authors: Aid Asma, Dahdouh Nadjib, Amokrane Samira, Ladjali Samir, Nibou Djamel

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The present work has for main objective the elimination of the textile dye Maxilon Red (MR) by two processes, adsorption on activated clay followed by photocatalysis in presence of ZnO as a photocatalyst. The influence of the physical parameters like the initial pH, adsorbent dose of the activated clay, the MR concentration and temperature has been studied. The best adsorption yield occurs at neutral pH ~ 7 within 60 min with an uptake percentage of 97% for a concentration of 25 mg L⁻¹ and a dose of 0.5 g L⁻¹. The adsorption data were suitably fitted by the Langmuir model with a maximum capacity of 176 mg g⁻¹. The MR adsorption is well described by the pseudo second order kinetic. The second part of this work was dedicated to the photocatalytic degradation onto ZnO under solar irradiation of the residual MR concentration, remained after adsorption. The effect of ZnO dose and MR concentration has also been investigated. The parametric study showed that the elimination is very effective by this process, based essentially on the in situ generation of free radicals *OH which are non-selective and very reactive. The photodegradation process follows a first order kinetic model according to the Langmuir-Hinshelwood model.

Keywords: maxilon red, adsorption, photodegradation, ZnO, coupling

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Authors: Saleh Komies, Mona Alharbi, Razan Alhayyani, Mozah Almulhim, Roseanne Khawaja, Ahmed Alradhi

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One of the proposed solutions that faces some challenges is encouraging sustainable energy consumption across Saudi Arabia through crowdfunding platforms. To address these challenges, we need to determine the level of awareness of crowdfunding and green projects, as well as the preferences and willingness of Saudis to utilize crowdfunding as an alternative funding source for green projects in Saudi Arabia. In this study, we aim to determine the influence of environmental awareness and concern on the propensity to crowdfund green projects. The survey is being conducted as part of environmental initiatives to assess public perceptions and opinions on crowdfunding green projects in Saudi Arabia. A total of 450 responses to an online questionnaire distributed via convenience and snowball sampling were utilized for data analysis. The survey reveals that Saudis have a low understanding of crowdfunding concepts and a relatively high understanding of implementing green projects. The public is interested in crowdfunding green projects if there is a return on investment.

Keywords: crowdfunding, green projects, awareness, Saudi Arabia, energy, solar, wind

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Authors: M. Mortada, A. Seleem, M. El-Morsi, M. Younan

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The present study introduces the folding technology to be utilized for the first time in vertical diffusion stills. This work represents a model of the distillation process by utilizing chevron pattern of folded structure. An experimental setup has been constructed, to investigate the performance of the folded sheets in the vertical effect diffusion still for a specific range of operating conditions. An experimental comparison between the folded type and the flat type sheets has been carried out. The folded pattern showed a higher performance and there is an increase in the condensate to feed ratio that ranges from 20-30 % through the operating hot plate temperature that ranges through 60-90°C. In addition, a parametric analysis of the system using Design of Experiments statistical technique, has been developed using the experimental results to determine the effect of operating conditions on the system's performance and the best operating conditions of the system has been evaluated.

Keywords: chevron pattern, fold structure, solar distillation, vertical diffusion still

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Authors: Pakhil Singh, Rahul Singh, Mohammad Saad Alam, Yasser Rafat

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The battery management system is an essential package/system which ensures optimum performance and safety of a battery by monitoring the key essential parameters of the battery like the voltage, current, temperature, state of charge, state of health during charging and discharging. This can be accomplished using outputs of various sensors employed to serve the purpose. The increasing demand for electricity generation from renewable energy sources requires proper storage and hence a proper monitoring system as well. A battery management system is required in wide applications ranging from renewable energy storage systems, off-grid solar PV applications to electric vehicles. The aim of this paper is to study the parameters used in monitoring various battery operating conditions and proposes the usage of the internet of things (IoT) to implement a reliable battery management system.

Keywords: electric vehicles, internet of things, sensors, state of charge, state of health

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Authors: Maria Albuquerque, Miguel Matias, Ângelo Sá, Juliana Sousa, Maria Manuel Mouzinho

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Obesity is a frequent disease in Portugal. The surgical treatment is very effective and has an indication when there is a failure of the medical treatment. Although massive weight loss is associated with considerable health gains, these patients are characterized by a variable degree of dermolipodistrophy. In some cases, there is even the development of physical symptoms such as intertriginous, and some degree of psychological distress is present. In almost all cases, a desire for a better body contour, which inhibits some aspects of social life, is a fact. A prospective study was made to access the impact of body contouring surgery in the quality of life of patients who underwent a massive weight lost correction surgical procedure at Centro Hospitalar de Lisboa Central between January 2020 and December 2021. The patients were submitted to the Body Q subjective questionnaire adapted for the Portuguese language and accessed for the following categories: Anguish with Appearance, Contempt with Body Image, Satisfaction with the Abdomen, and Overall Satisfaction with the Body. The questionnaire was repeated at the 6 months mark. A total of 80 patients were sampled. The sex distribution was 79 female and 1 male. The median BMI index before surgery was inferior to 28%. The pre operatory questionnaire showed high scores for Anguish with Appearance and low scores for the body image self-evaluation. Overall, there was an improvement of at least 50% in all the evaluated scores. Additionally, a correlation was found between abdominoplasty and the contempt with body image and satisfaction with the abdomen (p-value <0.05). Massive weight loss is associated with important body deformities that have a significant impact on the patient’s personal and social life. Body contouring surgery is then vital for these patients as it implicates major aesthetic and functional benefits.

Keywords: abdominoplasty, cruroplasty, obesity, massive weight loss

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Authors: P. C. Okafor, A. J. Ekpunobi

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Mn doped copper sulphide (CuS:Mn) nano-films were deposited on indiums coated tin oxide (ITO) glass substrates using electrodeposition method. Electrodeposition was carried out using bath of PH = 3 at room temperature. Other depositions parameters such as deposition time (DT) are kept constant while Mn doping was varied from 3% to 23%. Absorption spectra of CuS:Mn films was obtained by using JENWAY 6405 UV-VIS -spectrophotometer. Optical band gap (E_g ), optical conductivity (σo) and electrical conductivity (σe) of CuS:Mn films were determined using absorption spectra and appropriate formula. The effect of Mn doping % on these properties were investigated. Results show that film thickness (t) for the 13.27 nm to 18.49 nm; absorption coefficient (α) from 0.90 x 1011 to 1.50 x 1011 optical band gap from 2.29eV to 2.35 eV; optical conductivity from 1.70 x 1013 and electrical conductivity from 160 millions to 154 millions. Possible applications of such films for solar cells fabrication and optoelectronic devices applications were also discussed.

Keywords: copper sulphide (CuS), Manganese (Mn) doping, electrodeposition, optical band gap, optical conductivity, electrical conductivity

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Authors: Zair Mohammed El Amine, Chemouri Hafida, Derbal Habak Hassina

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Organic photovoltaic cells are electronic devices that convert sunlight into electricity. To this end, the number of studies on organic photovoltaic cells (OVCs) is growing, and this trend is expected to continue. Computational studies are still needed to verify and prove the capability of CVOs, specifically the nanometer molecule PCBM, based on successful experimental results. In this paper, we present a theoretical and computational investigation of PCBM and PC71BM derivatives using the DFT method. On this basis, we employ independent and time-dependent density theories. HOMO, LUMO and GAPH-L energies, ionization potentials and electronic affinity are determined and found to be in agreement with experiments. Using DFT theory based on B3LYP and M062X methods with bases 6-31G (d,p) and 6-311G (d), calculations show that the most efficient acceptors are presented in the group of PC71BM derivatives and are in substantial agreement with experiments. The geometries of the structures are optimized by Gaussian 09.

Keywords: PCBM, P3HT, organic cell solar, DFT, TD-DFT

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Authors: M. Johnson, R. Faggian, V. Sposito

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A participatory and engaged approach is key in connecting agricultural managers to sustainable agricultural systems to support and optimize production in Victoria’s food bowl. A sustainable intensification (SI) approach is well documented globally, but participation rates amongst Victorian farmers is fragmentary, and key outcomes and implementation strategies are poorly understood. Improvement in decision-support management tools and a greater understanding of the productivity gains available upon implementation of SI is necessary. This paper reviews the current understanding and uptake of SI practices amongst farmers in one of Victoria’s premier food producing regions, the Goulburn Broken; and it spatially analyses the potential for this region to adapt to climate change and optimize food production. A Geographical Information Systems (GIS) approach is taken to develop an interactive decision-support tool that can be accessible to on-ground agricultural managers. The tool encompasses multiple criteria analysis (MCA) that identifies factors during the construction phase of the tool, using expert witnesses and regional knowledge, framed within an Analytical Hierarchy Process. Given the complexities of the interrelations between each of the key outcomes, this participatory approach, in which local realities and factors inform the key outcomes and help to strategies for a particular region, results in a robust strategy for sustainably intensifying production in key food producing regions. The creation of an interactive, locally embedded, decision-support management and education tool can help to close the gap between farmer knowledge and production, increase on-farm adoption of sustainable farming strategies and techniques, and optimize farm productivity.

Keywords: agriculture, decision-support management tool, Geographic Information System, GIS, sustainable intensification

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Authors: Nirali Shukla, Neel Shah

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The World Bank Institute (WBI) is undertaking a review of government interventions aimed at facilitating sustainable investment in public private partnerships (PPPs) in various under developed countries. The study presents best practice for applying financial model to make PPPs financially viable. The lessons presented here, if properly implemented, can help countries use limited funds to attract more private investment, get more infrastructure built and, as a result, achieve greater economic growth. The four countries Brazil, Colombia, Mexico, and India in total develop an average of nearly US$50 billion in PPPs per year. There are a range of policies and institutional arrangements governments use to provide subsidies to PPPs. For example, some countries have created dedicated agencies, or ‘funds’, capitalized with money from the national budget to manage and allocate subsidies. Other countries have established well-defined policies for appropriating subsidies on an ad hoc basis through an annual budget process. In this context, subsidies are direct fiscal contributions or grants paid by the government to a project when revenues from user fees are insufficient to cover all capital and operating costs while still providing private investors with a reasonable rate of return. Without subsidies, some infrastructure projects that would provide economic or social gains, but are not financially viable, would go undeveloped. But the Financial model of BOLT (PPP) model described in this study suggests that it is most feasible option rather than going for subsidy schemes for making infrastructure projects financially viable. The major advantage for implementing this model is the government money is saved and can be used for other projects as well as the private investors are getting better rate of return than subsidized schemes.

Keywords: PPP, BOLT, subsidy schemes, financial model

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Authors: Syakirin O. Yong, Nasrudin A. Rahim, Bilal M. Eid, Buray Tankut

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The aim of this paper is to develop an ultra-fast gate driver for Silicon Carbide (SiC) based switching device applications such as AC/DC DC/AC converters. Wide bandgap semiconductors such as SiC switches are growing rapidly nowadays due to their numerous capabilities such as faster switching, higher power density and higher voltage level. Wide band-gap switches can work properly on high frequencies such 50-250 kHz which is very useful for many power electronic applications such as solar inverters. Increasing the frequency minimizes the output filter size and system complexity however, this causes huge spike between MOSFET’s drain and source leg which leads to the failure of MOSFET if the voltage rating is exceeded. This paper investigates and concludes the optimum design for a gate drive board for SiC MOSFET switches without causing spikes and noises.

Keywords: PV system, lithium-ion, charger, constant current, constant voltage, renewable energy

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Authors: Camille Lacan, Pierre Desmet

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In the crowdfunding model, a campaign succeeds by collecting the funds required over a predefined duration. The success of a CF campaign depends both on the capacity to attract members of the online communities concerned, and on the community members’ involvement in online word-of-mouth recommendations. To maximize the campaign's success probability, project creators (i.e., an organization appealing for financial resources) send messages to contributors to ask them to issue word of mouth. Internet users relay information about projects through Word of Mouth which is defined as “a critical tool for facilitating information diffusion throughout online communities”. The effectiveness of these messages depends on the message framing and the time at which they are sent to contributors (i.e., at the start of the campaign or close to the deadline). This article addresses the following question: What are the effect of message framing and temporal distance on the willingness to share word of mouth? Drawing on Perspectives Theory and Construal Level Theory, this study examines the interplay between message framing (Gains vs. Losses) and temporal distance (message while the deadline is coming vs. far) on intention to share word of mouth. A between-subject experimental design is conducted to test the research model. Results show significant differences between a loss-framed message (lack of benefits if the campaign fails) associated with a short deadline (ending tomorrow) compared to a gain-framed message (benefits if the campaign succeeds) associated with a distant deadline (ending in three months). However, this effect is moderated by the anticipated regret of a campaign failure and the temporal orientation. These moderating effects contribute to specifying the boundary condition of the framing effect. Handling the message framing and the temporal distance are thus the key decisions to influence the willingness to share word of mouth.

Keywords: construal levels, crowdfunding, message framing, word of mouth

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Authors: Tedros Asefaw Gebremeskel, Xaoyi Yang

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The potential of solar energy in Eritrea is relatively high, based on this truth, there are a number of isolated and remote villages situated far away from the electrical national grid which don’t get access to electricity. The core objective of this work is to design a most favorable and cost-effective power by means of standalone PV system for the electrification of a single housing in the inaccessible area of Eritrea. The sizing of the recommended PV system is achieved, such as radiation data and electrical load for the typical household of the selected site is also well thought-out in the design steps. Finally, the life cycle cost (LCC) analysis is conducted to evaluate the economic viability of the system. The outcome of the study promote the use of PV system for a residential building and show that PV system is a reasonable option to provide electricity for household applications in the rural area of Eritrea.

Keywords: electrification, inaccessible area, life cycle cost, residential building, stand-alone PV system

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Authors: A. Seleem, M. Mortada, M. El-Morsi, M. Younan

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Diffusion stills have been effective in water desalination. The present work represents a model of the distillation process by using vertical single-effect diffusion stills. A semi-analytical model has been developed to model the process. A software computer code using Engineering Equation Solver EES software has been developed to solve the equations of the developed model. An experimental setup has been constructed, and used for the validation of the model. The model is also validated against former literature results. The results obtained from the present experimental test rig, and the data from the literature, have been compared with the results of the code to find its best range of validity. In addition, a parametric analysis of the system has been developed using the model to determine the effect of operating conditions on the system's performance. The dominant parameters that affect the productivity of the still are the hot plate temperature that ranges from (55-90 °C) and feed flow rate in range of (0.00694-0.0211 kg/m2-s).

Keywords: analytical model, solar distillation, sustainable water systems, vertical diffusion still

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Authors: Draou Azeddine, Mazin Alahmadi, Abdulrahmane Alkassem, Alamri Abdullah

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The demand for electric power in Saudi Arabia is steadily increasing with economic growth. More power plants should be installed to increase generation capacity and meet demand. Electricity in Saudi Arabia is mainly dependent on fossil fuels, which are a major problem as they deplete natural resources and increase CO₂ emissions. In this research work, performance and techno-economic analyzes are conducted to evaluate a microgrid system based on hybrid PV/wind diesel power sources as a stand-alone system for rural electrification in Saudi Arabia. The total power flow, maximum power point tracking (MPPT) efficiency, effectiveness of the proposed control strategy, and total harmonic distortion (THD) are analyzed in MATLAB/Simulink environment. Various simulation studies have been carried out under different irradiation conditions. The sizing, optimization, and economic feasibility analysis were performed using Homer energy software.

Keywords: WIND, solar, microgrid, energy

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Authors: Hassam Muazzam

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This paper devises an autonomous self-driven vehicle that is capable of taking a disabled person to his/her desired location using three different power sources (gasoline, solar, electric) without any control from the user, avoiding the obstacles in the way. The GPS co-ordinates of the desired location are sent to the main processing board via a GSM module. After the GPS co-ordinates are sent, the path to be followed by the vehicle is devised by Pythagoras theorem. The distance and angle between the present location and the desired location is calculated and then the vehicle starts moving in the desired direction. Meanwhile real-time data from ultrasonic sensors is fed to the board for obstacle avoidance mechanism. Ultrasonic sensors are used to quantify the distance of the vehicle from the object. The distance and position of the object is then used to make decisions regarding the direction of vehicle in order to avoid the obstacles using artificial neural network which is implemented using ATmega1280. Also the vehicle provides the feedback location at remote location.

Keywords: autonomous self-driven vehicle, obstacle avoidance, desired location, pythagoras theorem, neural network, remote location

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Authors: Andrés Durán, Brian Castellanos, Marta Quicazán, Carlos Zuluaga-Domínguez

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Bee-pollen is an apicultural-derived food product, with a growing appreciation among consumers given the remarkable nutritional and functional composition, in particular, protein (24%), dietary fiber (15%), phenols (15 – 20 GAE/g) and carotenoids (600 – 900 µg/g). These properties are given by the geographical and climatic characteristics of the region where it is collected. There are several countries recognized by their pollen production, e.g. China, United States, Japan, Spain, among others. Beekeepers use traps in the entrance of the hive where bee-pollen is collected. After the removal of foreign particles and drying, this product is ready to be marketed. However, in countries located along the equator, the absence of seasons and a constant tropical climate throughout the year favors a more rapid spoilage condition for foods with elevated water activity. The climatic conditions also trigger the proliferation of microorganisms and insects. This, added to the factor that beekeepers usually do not have adequate processing systems for bee-pollen, leads to deficiencies in the quality and safety of the product. In contrast, the Andean region of South America, lying on equator, typically has a high production of bee-pollen of up to 36 kg/year/hive, being four times higher than in countries with marked seasons. This region is also located in altitudes superior to 2500 meters above sea level, having extremes sun ultraviolet radiation all year long. As a mechanism of defense of radiation, plants produce more secondary metabolites acting as antioxidant agents, hence, plant products such as bee-pollen contain remarkable more phenolics and carotenoids than collected in other places. Considering this, the improvement of bee-pollen processing facilities by technical modifications and the implementation of an integrated cleaning and drying system for the product in an apiary in the area was proposed. The beehives were modified through the installation of alternative bee-pollen traps to avoid sources of contamination. The processing facility was modified according to considerations of Good Manufacturing Practices, implementing the combined use of a cabin dryer with temperature control and forced airflow and a greenhouse-type solar drying system. Additionally, for the separation of impurities, a cyclone type system was implemented, complementary to a screening equipment. With these modifications, a decrease in the content of impurities and the microbiological load of bee-pollen was seen from the first stages, principally with a reduction of the presence of molds and yeasts and in the number of foreign animal origin impurities. The use of the greenhouse solar dryer integrated to the cabin dryer allowed the processing of larger quantities of product with shorter waiting times in storage, reaching a moisture content of about 6% and a water activity lower than 0.6, being appropriate for the conservation of bee-pollen. Additionally, the contents of functional or nutritional compounds were not affected, even observing an increase of up to 25% in phenols content and a non-significant decrease in carotenoids content and antioxidant activity.

Keywords: beekeeping, drying, food processing, food safety

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Authors: Martin Botz, Michael Kraus, Geralt Siebert

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The use of laminated glass gains increasing importance in structural engineering. For safety reasons, at least two glass panes are laminated together with a polymeric interlayer. In case of breakage of one or all of the glass panes, the glass fragments are still connected to the interlayer due to adhesion forces and a certain residual load-bearing capacity is left in the system. Polymer interlayers used in the laminated glass show a viscoelastic material behavior, e.g. stresses and strains in the interlayer are dependent on load duration and temperature. In the intact stage only small strains appear in the interlayer, thus the material can be described in a linear way. In the broken stage, large strains can appear and a non-linear viscoelasticity material theory is necessary. Relaxation tests on two different types of polymeric interlayers are performed at different temperatures and strain amplitudes to determine the border to the non-linear material regime. Based on the small-scale specimen results further tests on broken laminated glass panes are conducted. So-called ‘through-crack-bending’ (TCB) tests are performed, in which the laminated glass has a defined crack pattern. The test set-up is realized in a way that one glass layer is still able to transfer compressive stresses but tensile stresses have to be transferred by the interlayer solely. The TCB-tests are also conducted under different temperatures but constant force (creep test). Aims of these experiments are to elaborate if the results of small-scale tests on the interlayer are transferable to a laminated glass system in the broken stage. In this study, limits of the applicability of linear-viscoelasticity are established in the context of two commercially available polymer-interlayers. Furthermore, it is shown that the results of small-scale tests agree to a certain degree to the results of the TCB large-scale experiments. In a future step, the results can be used to develop material models for the post breakage performance of laminated glass.

Keywords: glass breakage, laminated glass, relaxation test, viscoelasticity

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Authors: Ahmad Almaududy Amri

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Southeast Asia is considered as an area which is important in terms of piratical studies. There are several reasons to this argument: firstly, it has the second highest figure of piracy attacks in the world from 2008 to 2012. Only the African Region transcends the number of piracies that were committed in Southeast Asia. Secondly, the geographical location of the region is very important to world trade. There are several sea lanes and straits which are normally used for international navigation mainly for trade purposes. In fact, there are six out of 25 busiest ports all over the world located in Southeast Asia. In ancient times, the main drivers of piracy were raiding for plunder and capture of slaves; however, in modern times, developments in politics, economics and even military technology have drastically altered the universal crime of piracy. There are a variety of motives behind modern day piracy including economic gains from receiving ransoms from government or ship companies, political and even terrorist reasons. However, it cannot be denied that piratical attacks persist and continue. States have taken measures both at the international and regional level in order to eradicate piratical attacks. The United Nations Convention on the Law of the Sea and the Convention on the Suppression of Unlawful Act against the Safety of Navigation served as the two main international legal frameworks in combating piracy. At the regional level, Regional Cooperation Agreement against Piracy and Armed Robbery and ASEAN measures are regard as prominent in addressing the piracy problem. This paper will elaborate the problems of piracy in Southeast Asia and examine the adequacy of legal frameworks at both the international and regional levels in order address the current legal measures in combating piracy. Furthermore, it will discuss current challenges in the implementation of anti-piracy measures at the international and regional levels as well as the way forward in addressing the issue.

Keywords: piracy, Southeast Asia, maritime security, legal frameworks

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Authors: Carolina L. Cerdeira, Julia V. F. Cortes, Maria E. V. Amarante, Gersika B. Santos

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Skin cancer is the most common cancer in several parts of the world; in a tropical country like Brazil, the situation isn’t different. The Brazilian population is exposed to high levels of solar radiation, increasing the risk of developing cutaneous carcinoma. Aimed at encouraging prevention measures and the early diagnosis of these tumors, a study was carried out that analyzed data on cutaneous melanomas, basal cell, and epidermoid carcinomas, using as primary data source the medical records of 161 patients registered in one pathology service, which performs skin biopsies in a city of Minas Gerais, Brazil. All patients diagnosed with skin cancer at this service from January 2015 to December 2019 were included. The incidence of skin carcinoma cases was correlated with the identification of histological type, sex, age group, and topographic location. Correlation between variables was verified by Fisher's exact test at a nominal significance level of 5%, with statistical analysis performed by R® software. A significant association was observed between age group and type of cancer (p=0.0085); age group and sex (0.0298); and type of cancer and body region affected (p < 0.01). Those 161 cases analyzed comprised 93 basal cell carcinomas, 66 epidermoid carcinomas, and only two cutaneous melanomas. In the group aged 19 to 30 years, the epidermoid form was most prevalent; from 31 to 45 and from 46 to 59 years, the basal cell prevailed; in 60-year-olds or over, both types had higher frequencies. Associating age group and sex, in groups aged 18 to 30 and 46 to 59 years, women were most affected. In the 31-to 45-year-old group, men predominated. There was a gender balance in the age group 60-year-olds or over. As for topography, there was a high prevalence in the head and neck, followed by upper limbs. Relating histological type and topography, there was a prevalence of basal cell and epidermoid carcinomas in the head and neck. In the chest, the basal cell form was most prevalent; in upper limbs, the epidermoid form prevailed. Cutaneous melanoma affected only the chest and upper limbs. About 82% of patients 60-year-olds or over had head and neck cancer; from 46 to 59 and 60-year-olds or over, the head and neck region and upper limbs were predominantly affected; the distribution was balanced in the 31-to 45-year-old group. In conclusion, basal cell carcinoma was predominant, whereas cutaneous melanoma was the rarest among the types analyzed. Patients 60-year-olds or over were most affected, showing gender balance. In young adults, there was a prevalence of the epidermoid form; in middle-aged patients, basal cell carcinoma was predominant; in the elderly, both forms presented with higher frequencies. There was a higher incidence of head and neck cancers, followed by malignancies affecting the upper limbs. The epidermoid type manifested significantly in the upper limbs. Body regions such as the thorax and lower limbs were less affected, which is justified by the lower exposure of these areas to incident solar radiation.

Keywords: basal cell carcinoma, cutaneous melanoma, skin cancer, squamous cell carcinoma, topographic location

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Authors: Yehya Abdellatif, Iyad M. Muslih, Azzah Alkhalailah, Abdallah Muslih

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Hybrid Optimization Model for Electric Renewable (HOMER) software was utilized to find the optimum design of a hybrid off-Grid system, by choosing the optimal solution depending on the cost analysis of energy based on different capacity shortage percentages. A complete study for the site conditions and load profile was done to optimize the design and implementation of a hybrid off-grid power station. In addition, the solution takes into consecration the ambient temperature effect on the efficiency of the power generation and the economical aspects of selection depending on real market price. From the analysis of the HOMER model results, the optimum hybrid power station was suggested, based on wind speed, and solar conditions. The optimization function objective is to minimize the Net Price Cost (NPC) and the Cost of Energy (COE) with zero and 10 percentage of capacity shortage.

Keywords: energy modeling, HOMER, off-grid system, optimization

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Authors: Nkrumak Micheal Atta Ofori

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The Vocational System is a decentralized Studies System implemented in Ghana as vocation studies strategy for grassroot that focuses on providing individuals with the specific skills, knowledge, and training necessary for a particular trade, craft, profession, or occupation. This article asks how devolution of vocational studies to local level authorities produces responsive and accountable representation and sustainable vocational learning under the vocational Studies System. It focuses on two case studies: Asokore Mampong and Atwima kwanwoma Municipal. Then, the paper asks how senior high school are developing new material and social practices around the vocational studies System to rebuild their livelihoods and socio-economic wellbeing. Here, the article focusses on Kumasi District, drawing lessons for the two other cases. The article shows how the creation of representative groups under the Vocational Studies System provides the democratic space necessary for effective representation of community aspirations. However, due to elite capture, the interests of privilege few people are promoted. The state vocational training fails to devolve relevant and discretionary resources to local teachers and do not follow the prescribed policy processes of the Vocational Studies System. Hence, local teachers are unable to promote responsive and accountable representation. Rural communities continue to show great interest in the Vocational Studies System, but the interest is bias towards gaining access to vocational training schools for advancing studies. There is no active engagement of the locals in vocational training, and hence, the Vocational Studies System exists only to promote individual interest of communities. This article shows how ‘failed’ interventions can gain popular support for rhetoric and individual gains.

Keywords: vocational studies system, devolution of vocational studies, local-level authorities, senior high schools and vocational learning, community aspirations and representation

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Authors: Lin Wenli, Fu Linchun, Zhang Yi, Wu Ming

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To meet the demands of long-life and high-intelligence for satellites, the electrical power system should be provided with self-health condition evaluation capability. Any over-stress events in operations should be recorded. Based on Linear stresses accumulation damage theory, accumulative damage analysis was performed on thermal-mechanical-electrical united stresses for three components including the solar array, the batteries and the power conditioning unit. Then an overall health percentage evaluation model for satellite electrical power system was built. To obtain the accurate quantity for system health percentage, an automatic feedback closed-loop correction method for all coefficients in the evaluation model was present. The evaluation outputs could be referred as taking earlier fault-forecast and interventions for Ground Control Center or Satellites self.

Keywords: satellite electrical power system, health percentage, linear stresses accumulation damage, evaluation model

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Authors: Ahmad Alduweesh

Abstract:

Self-cleaning surfaces have become essential in various applications. For instance, in photovoltaics, they provide an easy-cost effecting way to keep the solar cells clean. Titanium dioxide (TiO₂) nanoparticles were fabricated at different thicknesses to study the effect of different thicknesses on the hydrophilicity behavior of TiO₂, eventually leading to customizing hydrophilicity levels to desired values under natural light. As a result, a remarkable increase was noticed in surface hydrophilicity after applying thermal annealing on the as-deposited TiO₂ thin-films, with contact angle dropping from around 85.4ᵒ for as-deposited thin-films down to 5.1ᵒ for one of the annealed samples. The produced thin films were exposed to the outside environment to observe the effect of dust. The transmittance of light using UV-VIS spectroscopy will be conducted on the lowest and highest thicknesses (5-40 nm); this will show whether the Titania has successfully enabled more sunlight to penetrate the glass or not. Surface characterizations, including AFM and contact angle, have been included in this test.

Keywords: physical vapor deposition, TiO₂, nano-thin films, hydrophobicity, hydrophilicity, self-cleaning surfaces

Procedia PDF Downloads 100