Search results for: allowable load capacity

Authors: A. M. Al-Sabagh, M. A. Deyab, M. N. Kroush

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The present study focused on critical and detailed approach for using aluminum electrode as impressed current anode for cathodic protection of X65 steel tank containing fresh water. The impressed current design calculation showed 0.6 A of current demand and voltage of 0.33 V required to adequately protect the X65 steel tank with internal surface area of 421 m². We used here one transformer rectifier with current and voltage output of 25 A and 25 V, respectively. The data showed that the potentials ranged from -0.474 to -0.509 V (vs. Cu/CuSO₄), prior to the application of cathodic protection. When the potential was measured 1 h after the application of cathodic protection, the potential values showed considerable shift within protection range (-0.950 V vs. Cu/CuSO₄). The results confirmed that aluminum anode can be used in freshwater applications with high efficiency (current capacity) and low consumption rate.

Keywords: cathodic protection, aluminum, steel, fresh water

Procedia PDF Downloads 158

Authors: Mohamed A. Safan, Walid Khalil, Amro Fathalla

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Advances in concrete technology and implementation of new materials made it possible to produce special types of concrete for different structural applications. In this research, granite and galena were incorporated in different concrete mixes to obtain high performance concrete for shielding against gamma radiations in nuclear facilities. Chemically prepared industrial galena was used to replace different volume fractions of the fine aggregate. The test specimens were exposed to different conditions of heating cycles and irradiation. The exposed specimens and counterpart unexposed specimens were tested to evaluate the density, the compressive strength and the attenuation coefficient. The proposed mixes incorporating galena showed better performance in terms of compressive strength and gamma attenuation capacity, especially after the exposure to different heating cycles.

Keywords: concrete, galena, shielding, attenuation, radiation

Procedia PDF Downloads 464

Authors: Ahmad Abubakar Sadiq, Nwohu Ndubuka Mark, Jacob Tsado, Ahmad Adam Asharaf, Agbachi E. Okenna, Enesi E. Yahaya, Ambafi James Garba

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Transmission system performance analysis is vital to proper planning and operations of power systems in the presence of deregulation. Key performance indicators (KPIs) are often used as measure of degree of performance. This paper gives a novel method to determine the transmission efficiency by evaluating the ratio of real power losses incurred from a specified transfer direction. Available Transmission Transfer Efficiency (ATTE) expresses the percentage of real power received resulting from inter-area available power transfer. The Tie line (Rated system path) performance is seen to differ from system wide (Network response) performance and ATTE values obtained are transfer direction specific. The required sending end quantities with specified receiving end ATC and the receiving end power circle diagram are obtained for the tie line analysis. The amount of real power loss load relative to the available transfer capability gives a measure of the transmission grid efficiency.

Keywords: performance, transmission system, real power efficiency, available transfer capability

Procedia PDF Downloads 654

Authors: M. Khaled Abduesslam, Mohammed Ali, Basher H. Alsdai, Muhammad Nizam Inayati

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This paper presents the voltage problem location classification using performance of Least Squares Support Vector Machine (LS-SVM) and Learning Vector Quantization (LVQ) in electrical power system for proper voltage problem location implemented by IEEE 39 bus New-England. The data was collected from the time domain simulation by using Power System Analysis Toolbox (PSAT). Outputs from simulation data such as voltage, phase angle, real power and reactive power were taken as input to estimate voltage stability at particular buses based on Power Transfer Stability Index (PTSI).The simulation data was carried out on the IEEE 39 bus test system by considering load bus increased on the system. To verify of the proposed LS-SVM its performance was compared to Learning Vector Quantization (LVQ). The results showed that LS-SVM is faster and better as compared to LVQ. The results also demonstrated that the LS-SVM was estimated by 0% misclassification whereas LVQ had 7.69% misclassification.

Keywords: IEEE 39 bus, least squares support vector machine, learning vector quantization, voltage collapse

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Authors: L. Rozumová, J. Seidlerová

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The aim of this paper was to study the sorption properties of a blast furnace sludge used as the sorbent. The sorbent was utilized for reduction of content of lead and zinc ions. Sorbent utilized in this work was obtained from metallurgical industry from process of wet gas treatment in iron production. The blast furnace sludge was characterized by X-Ray diffraction, scanning electron microscopy, and XRFS spectroscopy. Sorption experiments were conducted in batch mode. The sorption of metal ions in the sludge was determined by correlation of adsorption isotherm models. The adsorption of lead and zinc ions was best fitted with Langmuir adsorption isotherms. The adsorption capacity of lead and zinc ions was 53.8 mg.g^-1 and 10.7 mg.g^-1, respectively. The results indicated that blast furnace sludge could be effectively used as secondary material and could be also employed as a low-cost alternative for the removal of heavy metals ions from wastewater.

Keywords: blast furnace sludge, lead, zinc, sorption

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Authors: Veronika Pivkina, Alla Kim, Khon Nataliya

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Actuality of the present study is defined first of all the role of subjective well-being problem in modern psychology and the comprehending of subjective well-being by current students. Purpose of this research is to educe peculiarities of comprehending of subjective well-being by students with various levels of emotional intelligent. Methods of research are adapted Russian-Language questionnaire of K. Riff 'The scales of psychological well-being'; emotional intelligent questionnaire of D. V. Lusin. The research involved 72 student from different universities and disciplines aged between 18 and 24. Analyzing the results of the studies, it can be concluded that the understanding of happiness in different groups of students with high and low levels of overall emotional intelligence is different, as well as differentiated by gender. Students with higher level of happiness possess more capacity and higher need to control their emotions, to cause and maintain the desired emotions and control something undesirable.

Keywords: subjective well-being, emotional intelligent, psychology of comprehending, students

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Authors: Marcela dos P. G. Baltazar, Louise H. Gracioso, Luciana J. Gimenes, Bruno Karolski, Ingrid Avanzi, Elen A. Perpetuo

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In this work, bacterial strains were isolated from environmental samples from a copper mine and three of them presented potential for bioremediation of copper. All the strains were identified by mass spectrometry (MALDI-TOF-Biotyper) and grown in three diferent media supplemented with 100 ppm of copper chloride in flasks of 500mL and it was incubated at 28 °C and 180 rpm. Periodically, samples were taken and monitored for cellular growth and copper biosorption by spectrophotometer UV-Vis (600 nm) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), respectively. At the end of exponential phase of cellular growth, the biomass was utilized to construct a correlation curve between absorbance and dry mass of the cells. Among the three isolates with potential for biorremediation, 1 strain exhibit capacity the most for bioremediation of effluents contaminated by copper being identified as Rhodococcus erythropolis.

Keywords: bioprocess, bioremediation, biosorption, copper

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Authors: Simiso Fisokuhle Nyandeni

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Climate change has turned out to be a pandemic that has drawn the attention of many countries’ households around the globe, especially those whose livelihood and economic status depend on agricultural productivity. Hence, the agricultural sector is regarded as the sector that is most dependent on climate conditions for its productivity/harvest, yet in recent years this sector has been experiencing drought. However, adaptation seems to be a tool that every farmer looks upon as a solution to their challenges as their productivity keeps on being vulnerable to climate effects. Thus, exposure/access to the market seems to be a major challenge that faces especially small-scale farmers. We, therefore, examine the small-scale farmers’ constraints or challenges towards getting access to the market for them to get proper sales of their farming products. As a result, the adaptation capacity of every farm household varies on the financial status.

Keywords: climate change, small-scale farming, agriculture sector, adaptation

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Authors: Chinazo Onyeka Eziuzo

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This work presents the simulation and control of the flywheel system in the rotor of a wind turbine using Simulink and OpenFAST for assessing the effect on the mechanical loads. This concept allows the flywheel system to serve two main tasks: supporting the power system and mitigating the mechanical loads in the wind turbine. These tasks are grouped into four control scenarios; scenario 1 represents steadying the power infeed in the Flywheel, scenario 2 represents steadying power with FW and grid loss, scenario 3 represents mitigating excitations from gravity, and scenario 4 represents damping in-plane blade vibrations. The s-function of the OpenFAST model was used to substitute the given 1st Eigen mode model of the WT. After that, the simulations were run for the above-listed scenarios. Additionally, the effects of the control options on the mechanical loads were assessed, and it was established that the FW system assists in steadying infeed power and mechanical load mitigation.

Keywords: simulation, control, wind turbine, OpenFAST

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Authors: Albert T. Akume, Ankama G. Rosecana, Micheal Solomon

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Every citizen has rights that must be respected by others in the community. Ironically however, women in most communities are not accorded some of those rights as the male folks. This has not only facilitated their disempowerment but inhibited them from being treated with equal dignity that they deserve as their male counterpart; despite their valuable contribution to the society. Those forces against women empowerment are not limited to socio-cultural practices alone, but the character and nature of the state in Nigeria point to indicators of systemic and structural exclusion embedded in its framework. The consequence of this is that the vital contributions of women to sustainable community development have eluded many communities in Nigeria with adverse tell-tell signs on the environment. It is for this reason that the objective of this study is not only to highlight the causes and challenges associated with women disempowerment, but also to draw attention to the need to correct those anomaly against women in order to genuinely empower them to contribute to sustainable community development in Nigeria.

Keywords: capacity development, community, social sustainability, sustainable development, women empowerment

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Authors: Md Abu Saieed

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Crafting and implementing public policy is one of the indispensable works in any form of state and government. But the policy objectives, methods of formulation and tools of implementation might be different based on the ideological nature, historical legacy, structure and capacity of administration and management and other push and factors. Public policy in Islamic economic system needs to be based on the key guidelines of divine scriptures along with other sources of sharia’h. As a representative of Allah (SWT), the governor and other apparatus of the state will formulate and implement public policies which will enable to establish a true welfare state based on justice, equity and equality. The whole life of Prophet Muhammad (pbuh) and his policy in operating state of affairs in Madina is the practical guidelines for the policy actors and professionals in Islamic system of economics. Moreover, policy makers need to be more meticulous in formulating Islamic public policy which meets the needs and demands of contemporary worlds as well.

Keywords: formulation, Islam, public policy, policy factors, Sharia’h

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Authors: Hilary Rutto, Mbali Chiliza, Tumisang Seodigeng

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The study on reactivity of calcined calcium-based material is very important in dry flue gas desulphurisation (FGD) process, so as to produce absorbent with high sulphur dioxide capture capacity during the hydration process. The effect of calcining temperature and time on the reactivity of calcined limestone material were investigated. In this study, the reactivity was measured using a pH stat apparatus and also confirming the result by performing citric acid reactivity test. The reactivity was calculated using the shrinking core model. Based on the experiments, a mathematical model is developed to correlate the effect of time and temperature to the reactivity of absorbent. The calcination process variables were temperature (700 -1000°C) and time (1-6 hrs). It was found that reactivity increases with an increase in time and temperature.

Keywords: reactivity, citric acid, calcination, time

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Authors: Ali Vaezi, Jyotirmoy Dalal, Manish Verma

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The railroad is one of the primary transportation modes for hazardous materials (hazmat) shipments in North America. Installing an emergency response network capable of providing a commensurate response is one of the primary levers to contain (or mitigate) the adverse consequences from rail hazmat incidents. To this end, we propose a two-stage stochastic program to determine the location of and equipment packages to be stockpiled at each response facility. The raw input data collected from publicly available reports were processed, fed into the proposed optimization program, and then tested on a realistic railroad network in Ontario (Canada). From the resulting analyses, we conclude that the decisions based only on empirical datasets would undermine the effectiveness of the resulting network; coverage can be improved by redistributing equipment in the network, purchasing equipment with higher containment capacity, and making use of a disutility multiplier factor.

Keywords: hazmat, rail network, stochastic programming, emergency response

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Authors: Shahriar Shahbazpanahi, Alaleh Kamgar

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So far, the conventional experimental and theoretical analysis in fracture mechanics have been applied to study concrete flexural- cracked beams, which are strengthened using fiber reinforced polymer (FRP) composite sheets. However, there is still little knowledge about the shear capacity of a side face FRP- strengthened shear-cracked beam. A numerical analysis is herein presented to model the fracture mechanics of a four-point RC beam, with two inclined initial notch on the supports, which is strengthened with side face FRP sheets. In the present study, the shear crack is forced to conduct by using an initial notch in supports. The ABAQUS software is used to model crack propagation by conventional cohesive elements. It is observed that the FRP sheets play important roles in preventing the propagation of shear cracks.

Keywords: crack, FRP, shear, strengthening

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Authors: Alessandro Marzucchini, Yie Sue Chua, Andrew Lian, Richard Shonn Mills

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A unique, fast and easy installed inter-module connection named Candle-Loc was developed and applied in several high-rise steel and reinforced concrete modular buildings in Singapore and Hong Kong, China. However, its effect on the global behaviour of modular buildings in high seismic zones was not studied. Therefore, the design concept and the structural performance of each component in this connection was investigated through analytical approach. Response spectrum, linear time-history, and nonlinear time-history analyses were conducted to investigate the effects of the different joint models of the Candle-Loc in the global analysis of high-rise buildings under high seismic loads. It is found that it is important to assess the level of plasticity developed in the inter-module connection under high seismic loads. The ductility of the lateral force resisting system influences the amount of load taken by the inter-module connections.

Keywords: high-rise, inter-module connection, nonlinear, seismic, time-history analysis

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Authors: Yasar Pala, Safa Senaysoy, Emre Calis

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In this paper, structural behavior and improvement of buckling behavior of cold formed steel uprights with open cross-section used storage rack system are studied. As a first step, in the case of a stiffener having an inclined part on the flange, experimental and nonlinear finite element analysis are carried out for three different upright lengths. In the uprights with long length, global buckling is observed while distortional buckling and local buckling are observed in the uprights with medium length and those with short length, respectively. After this point, the study is divided into two groups. One of these groups is the case where the stiffener on the flange is folded at 90°. For this case, four different distances of the stiffener from the web are taken into account. In the other group, the case where different depth of stiffener on the web is considered. Combining experimental and finite element results, the cross-section giving the ultimate critical buckling load is selected.

Keywords: steel, upright, buckling, modes, nonlinear finite element analysis, optimization

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Authors: Yekini N. Asafe, Haastrup A. Victor, Lawal N. Olawale, Okikiola F. Mercy

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Recent increase in access to personal computer and networking systems have made it feasible to perform much of cumbersome and costly paper-based administration in all organization. Desktop computers, networking systems, high capacity storage devices and telecommunications system is currently allowing the transfer of various format of data to be processed, stored and dissemination for the purpose of decision making. Going paperless is more of benefits compare to full paper-based office. This paper proposed a model for design and implementation of e-administration system (paperless campus) for an institution of learning. If this model is design and implemented it will reduced cost and complexity of educational administration also eliminate menaces and environmental hazards attributed to paper-based administration within schools and colleges.

Keywords: e-administration, educational administration, paperless campus, paper-based administration

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Authors: Kimia Khoshdel Vajari, Saber Saffar

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Reducing the residual stresses caused by welding is desirable for the industry. The effect of welding sequence, as well as the effect of yield stress on the number of residual stresses generated in Inconel X750 superalloy sheets and beams, have been investigated. The finite element model used in this research is a three-dimensional thermal and mechanical model, and the type of analysis is indirect coupling. This analysis is done in two stages. First, thermal analysis is performed, and then the thermal changes of the first analysis are used as the applied load in the second analysis. ABAQUS has been used for modeling, and the Dflux subroutine has been used in the Fortran programming environment to move the arc and the molten pool. The results of this study show that the amount of tensile residual stress in symmetric, discontinuous, and symmetric-discontinuous welds is reduced to a maximum of 27%, 54%, and 37% compared to direct welding, respectively. The results also show that the amount of residual stresses created by welding increases linearly with increasing yield stress with a slope of 40%.

Keywords: residual stress, X750 superalloy, finite element, welding, thermal analysis

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Authors: Mohammad Reza Esmaili

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After the occurrence of blackouts, the most important subject is how fast the electric service is restored. Power system restoration is an immensely complex issue and there should be a plan to be executed within the shortest time period. This plan has three main stages of black start, network reconfiguration and load restoration. In the black start stage, operators and experts may face several problems, for instance, the unsuccessful connection of the long high-voltage transmission line connected to the electrical source. In this situation, the generator may be tripped because of the unsuitable setting of its line charging mode or high absorbed reactive power. In order to solve this problem, the line charging process is defined as a nonlinear programming problem, and it is optimized by using GAMS software in this paper. The optimized process is performed on a grid that includes a 250 MW hydroelectric unit and a 400 KV transmission system. Simulations and field test results show the effectiveness of optimal planning.

Keywords: power system restoration, black start, line charging mode, nonlinear programming

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Authors: Sandip Mitra

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Studies on Governance and Accountability has often stressed the need to release Data in public domain to increase transparency ,which otherwise act as an evidence of performance. However, inefficient handling, lack of capacity and the dynamics of transfers (especially fund transfers) are important issues which need appropriate attention. E-Governance alone can not serve as a measure of transparency as long as a comprehensive planning is instituted. Studies on Governance and public exposure has often triggered public opinion in favour or against any government. The root of the problem (especially in local governments) lies in the management of the governance. The participation of the people in the local government functioning, the networks within and outside the locality, synergy with various layers of Government are crucial in understanding the activities of any government. Unfortunately, data on such issues are not released in the public domain .If they are at all released , the extraction of information is often hindered for complicated designs. A Study has been undertaken with a few local Governments in India. The data has been analysed to substantiate the views.

Keywords: accountability, e-governance, transparency, local government

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Authors: H. Masaeli, R. Ziaei, F. Khoshnoudian

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Shock response analysis of the soil–structure systems induced by near–fault pulses is investigated. Vibration transmissibility of the soil–structure systems is evaluated by Shock Response Spectra (SRS). Medium–to–high rise buildings with different aspect ratios located on different soil types as well as different foundations with respect to vertical load bearing safety factors are studied. Two types of mathematical near–fault pulses, i.e. forward directivity and fling step, with different pulse periods as well as pulse amplitudes are selected as incident ground shock. Linear versus nonlinear Soil–Structure Interaction (SSI) condition are considered alternatively and the corresponding results are compared. The results show that nonlinear SSI is likely to amplify the acceleration responses when subjected to long–period incident pulses with normalized period exceeding a threshold. It is also shown that this threshold correlates with soil type, so that increased shear–wave velocity of the underlying soil makes the threshold period decrease.

Keywords: nonlinear soil–structure interaction, shock response spectrum, near–fault ground shock, rocking isolation

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Authors: Esther Van Andel, Stefanie C. Lange, Maarten M. J. Smulders, Han Zuilhof

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False outcomes of diagnostic tests are a major concern in medical health care. To improve the reliability of surface-based diagnostic tests, it is of crucial importance to diminish background signals that arise from the non-specific binding of biomolecules, a process called fouling. The aim is to create surfaces that repel all biomolecules except the molecule of interest. This can be achieved by incorporating antifouling protein repellent coatings in between the sensor surface and it’s recognition elements (e.g. antibodies, sugars, aptamers). Zwitterionic polymer brushes are considered excellent antifouling materials, however, to be able to bind the molecule of interest, the polymer brushes have to be functionalized and so far this was only achieved at the expense of either antifouling or binding capacity. To overcome this limitation, we combined both features into one single monomer: a zwitterionic sulfobetaine, ensuring antifouling capabilities, equipped with a clickable azide moiety which allows for further functionalization. By copolymerizing this monomer together with a standard sulfobetaine, the number of azides (and with that the number of recognition elements) can be tuned depending on the application. First, the clickable azido-monomer was synthesized and characterized, followed by copolymerizing this monomer to yield functionalizable antifouling brushes. The brushes were fully characterized using surface characterization techniques like XPS, contact angle measurements, G-ATR-FTIR and XRR. As a proof of principle, the brushes were subsequently functionalized with biotin via strain-promoted alkyne azide click reactions, which yielded a fully zwitterionic biotin-containing 3D-functionalized coating. The sensing capacity was evaluated by reflectometry using avidin and fibrinogen containing protein solutions. The surfaces showed excellent antifouling properties as illustrated by the complete absence of non-specific fibrinogen binding, while at the same time clear responses were seen for the specific binding of avidin. A great increase in signal-to-noise ratio was observed, even when the amount of functional groups was lowered to 1%, compared to traditional modification of sulfobetaine brushes that rely on a 2D-approach in which only the top-layer can be functionalized. This study was performed on stoichiometric silicon nitride surfaces for future microring resonator based assays, however, this methodology can be transferred to other biosensor platforms which are currently being investigated. The approach presented herein enables a highly efficient strategy for selective binding with retained antifouling properties for improved signal-to-noise ratios in binding assays. The number of recognition units can be adjusted to a specific need, e.g. depending on the size of the analyte to be bound, widening the scope of these functionalizable surface coatings.

Keywords: antifouling, signal-to-noise ratio, surface functionalization, zwitterionic polymer brushes

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Authors: M. Arun, A. Kannan

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Textile industries cater to varied customer preferences and contribute substantially to the economy. However, these textile industries also produce a considerable amount of effluents. Prominent among these are the azo dyes which impart considerable color and toxicity even at low concentrations. Azo dyes are also used as coloring agents in food and pharmaceutical industry. Despite their applications, azo dyes are also notorious pollutants and carcinogens. Popular techniques like photo-degradation, biodegradation and the use of oxidizing agents are not applicable for all kinds of dyes, as most of them are stable to these techniques. Chemical coagulation produces a large amount of toxic sludge which is undesirable and is also ineffective towards a number of dyes. Most of the azo dyes are stable to UV-visible light irradiation and may even resist aerobic degradation. Adsorption has been the most preferred technique owing to its less cost, high capacity and process efficiency and the possibility of regenerating and recycling the adsorbent. Adsorption is also most preferred because it may produce high quality of the treated effluent and it is able to remove different kinds of dyes. However, the adsorption process is influenced by many variables whose inter-dependence makes it difficult to identify optimum conditions. The variables include stirring speed, temperature, initial concentration and adsorbent dosage. Further, the internal diffusional resistance inside the adsorbent particle leads to slow uptake of the solute within the adsorbent. Hence, it is necessary to identify optimum conditions that lead to high capacity and uptake rate of these pollutants. In this work, commercially available activated carbon was chosen as the adsorbent owing to its high surface area. A typical azo dye found in textile effluent waters, viz. the monoazo Acid Orange 10 dye (CAS: 1936-15-8) has been chosen as the representative pollutant. Adsorption studies were mainly focused at obtaining equilibrium and kinetic data for the batch adsorption process at different process conditions. Studies were conducted at different stirring speed, temperature, adsorbent dosage and initial dye concentration settings. The Full Factorial Design was the chosen statistical design framework for carrying out the experiments and identifying the important factors and their interactions. The optimum conditions identified from the experimental model were validated with actual experiments at the recommended settings. The equilibrium and kinetic data obtained were fitted to different models and the model parameters were estimated. This gives more details about the nature of adsorption taking place. Critical data required to design batch adsorption systems for removal of Acid Orange 10 dye and identification of factors that critically influence the separation efficiency are the key outcomes from this research.

Keywords: acid orange 10, activated carbon, optimum adsorption conditions, statistical design

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Authors: Erika T. Fajardo-Ariza, Luis A. Castillo-Sanabria, Andrea Nieto-Veloza, Carlos M. Zuluaga-Domínguez

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The growing emphasis on sustainable food production and preservation has driven the development of innovative solutions to minimize postharvest losses and improve market access for small-scale farmers. This project focuses on designing, constructing, and selecting materials for solar dryers in certain regions of Colombia where inadequate infrastructure limits access to major commercial hubs. Postharvest losses pose a significant challenge, impacting food security and farmer income. Addressing these losses is crucial for enhancing the value of agricultural products and supporting local economies. A comprehensive survey of local farmers revealed substantial challenges, including limited market access, inefficient transportation, and significant postharvest losses. For crops such as coffee, bananas, and citrus fruits, losses range from 0% to 50%, driven by factors like labor shortages, adverse climatic conditions, and transportation difficulties. To address these issues, the project prioritized selecting effective materials for the solar dryer. Various materials, recovered acrylic, original acrylic, glass, and polystyrene, were tested for their performance. The tests showed that recovered acrylic and glass were most effective in increasing the temperature difference between the interior and the external environment. The solar dryer was designed using Fusion 360® software (Autodesk, USA) and adhered to architectural guidelines from Architectural Graphic Standards. It features up to sixteen aluminum trays, each with a maximum load capacity of 3.5 kg, arranged in two levels to optimize drying efficiency. The constructed dryer was then tested with two locally available plant materials: green plantains (Musa paradisiaca L.) and snack bananas (Musa AA Simonds). To monitor performance, Thermo hygrometers and an Arduino system recorded internal and external temperature and humidity at one-minute intervals. Despite challenges such as adverse weather conditions and delays in local government funding, the active involvement of local producers was a significant advantage, fostering ownership and understanding of the project. The solar dryer operated under conditions of 31°C dry bulb temperature (Tbs), 55% relative humidity, and 21°C wet bulb temperature (Tbh). The drying curves showed a consistent drying period with critical moisture content observed between 200 and 300 minutes, followed by a sharp decrease in moisture loss, reaching an equilibrium point after 3,400 minutes. Although the solar dryer requires more time and is highly dependent on atmospheric conditions, it can approach the efficiency of an electric dryer when properly optimized. The successful design and construction of solar dryer systems in difficult-to-access areas represent a significant advancement in agricultural sustainability and postharvest loss reduction. By choosing effective materials such as recovered acrylic and implementing a carefully planned design, the project provides a valuable tool for local farmers. The initiative not only improves the quality and marketability of agricultural products but also offers broader environmental benefits, such as reduced reliance on fossil fuels and decreased waste. Additionally, it supports economic growth by enhancing the value of crops and potentially increasing farmer income. The successful implementation and testing of the dryer, combined with the engagement of local stakeholders, highlight its potential for replication and positive impact in similar contexts.

Keywords: drying technology, postharvest loss reduction, solar dryers, sustainable agriculture

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Authors: Danlei Yang, Luofeng Huang

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The integration of digital twin technology with renewable energy systems offers an innovative approach to predicting and optimising performance throughout the entire lifecycle. A digital twin is a continuously updated virtual replica of a real-world entity, synchronised with data from its physical counterpart and environment. Many digital twin companies today claim to have mature digital twin products, but their focus is primarily on equipment visualisation. However, the core of a digital twin should be its model, which can mirror, shadow, and thread with the real-world entity, which is still underdeveloped. For a floating solar energy system, a digital twin model can be defined in three aspects: (a) the physical floating solar energy system along with environmental factors such as solar irradiance and wave dynamics, (b) a digital model powered by artificial intelligence (AI) algorithms, and (c) the integration of real system data with the AI-driven model and a user interface. The experimental setup for the floating solar energy system, is designed to replicate real-ocean conditions of floating solar installations within a controlled laboratory environment. The system consists of a water tank that simulates an aquatic surface, where a floating catamaran structure supports a solar panel. The solar simulator is set up in three positions: one directly above and two inclined at a 45° angle in front and behind the solar panel. This arrangement allows the simulation of different sun angles, such as sunrise, midday, and sunset. The solar simulator is positioned 400 mm away from the solar panel to maintain consistent solar irradiance on its surface. Stability for the floating structure is achieved through ropes attached to anchors at the bottom of the tank, which simulates the mooring systems used in real-world floating solar applications. The floating solar energy system's sensor setup includes various devices to monitor environmental and operational parameters. An irradiance sensor measures solar irradiance on the photovoltaic (PV) panel. Temperature sensors monitor ambient air and water temperatures, as well as the PV panel temperature. Wave gauges measure wave height, while load cells capture mooring force. Inclinometers and ultrasonic sensors record heave and pitch amplitudes of the floating system’s motions. An electric load measures the voltage and current output from the solar panel. All sensors collect data simultaneously. Artificial neural network (ANN) algorithms are central to developing the digital model, which processes historical and real-time data, identifies patterns, and predicts the system’s performance in real time. The data collected from various sensors are partly used to train the digital model, with the remaining data reserved for validation and testing. The digital twin model combines the experimental setup with the ANN model, enabling monitoring, analysis, and prediction of the floating solar energy system's operation. The digital model mirrors the functionality of the physical setup, running in sync with the experiment to provide real-time insights and predictions. It provides useful industrial benefits, such as informing maintenance plans as well as design and control strategies for optimal energy efficiency. In long term, this digital twin will help improve overall solar energy yield whilst minimising the operational costs and risks.

Keywords: digital twin, floating solar energy system, experiment setup, artificial intelligence

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Authors: Elmabruk Laias

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IEEE Standard 802.16 provides QoS (Quality of Service) for the applications such as Voice over IP, video streaming and high bandwidth file transfer. With the ability of broadband wireless access of an IEEE 802.16 system, a WiMAX TDD frame contains one downlink subframe and one uplink subframe. The capacity allocated to each subframe is a system parameter that should be determined based on the expected traffic conditions. a proper resource allocation scheme for packet transmissions is imperatively needed. In this paper, we present a new resource allocation scheme, called additional bandwidth yielding (ABY), to improve transmission efficiency of an IEEE 802.16-based network. Our proposed scheme can be adopted along with the existing scheduling algorithms and the multi-priority scheme without any change. The experimental results show that by using our ABY, the packet queuing delay could be significantly improved, especially for the service flows of higher-priority classes.

Keywords: IEEE 802.16, WiMAX, OFDMA, resource allocation, uplink-downlink mapping

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Authors: Cheila Cristina Leonardo Oliveira Gaioli, Fernanda Ludmilla Rossi Rocha, Sandra Cristina Pillon

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Resilience is a psychological process that facilitates the maintenance of health, developed in response to numerous existing stressors in daily life. Furthermore, resilience can be described as the ability which allows an individual or group to hold up well before unfavorable situations. This study aimed to identify nursing workers’ resilience at a psychiatric hospital in Brazil. This is an exploratory research with quantitative data approach. The sample consisted of 56 workers, using the Resilience Scale. Of the 56 subjects, 45 (80.4%) were women; 22 (39.2%) were 20- to 40-years-old and 30 (53.6%) were 41- to 60-years-old; 11 (19.6%) were nurses and 45 (80.4%) were technicians or nursing assistants. The results also showed that 50% of subjects showed a high resilience degree and 42.9% an average resilience degree. Thus, it was found that workers seek to develop protective factors in coping with a work environment that does not value the individual subjectivity and does not allow professional development, discouraging workers.

Keywords: health promotion, nursing, occupational health, resilience

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Authors: S. Beekrum, B. Odhav, R. Lalloo, E. O. Amonsou

Abstract:

Marine microalgae are rich sources of the novel and biologically active metabolites; therefore, they may be used in the food industry as natural food ingredients and functional foods. They have several biological applications related with health benefits, among others. In the past decades, food scientists have been searching for natural alternatives to replace synthetic antioxidants. The use of synthetic antioxidants has decreased due to their suspected activity as promoters of carcinogenesis, as well as consumer rejection of synthetic food additives. The aim of the study focused on screening of phytochemicals from Cymbella biomass extracts, and to examine the in vitro antioxidant and antimicrobial potential. Cymbella biomass was obtained from CSIR (South Africa), and four different solvents namely methanol, acetone, n-hexane and water were used for extraction. To take into account different antioxidant mechanisms, seven different antioxidant assays were carried out. These include free radical scavenging (DPPH assay), Trolox equivalent antioxidant capacity (TEAC assay), radical cation (ABTS assay), superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The total content of phenol and flavonoid in extracts were determined as gallic acid equivalent, and as rutin equivalent, respectively. The in vitro antimicrobial effect of extracts were tested against some pathogens (Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis, Salmonella enteritidis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans), using the disc diffusion assay. Qualitative analyses of phytochemicals were conducted by chemical tests to screen for the presence of tannins, flavonoids, terpenoids, phenols, steroids, saponins, glycosides and alkaloids. The present investigation revealed that all extracts showed relatively strong antibacterial activity against most of the tested bacteria. The methanolic extract of the biomass contained a significantly high phenolic content of 111.46 mg GAE/g, and the hexane extract contained 65.279 mg GAE/g. Results of the DPPH assay showed that the biomass contained strong antioxidant capacity, 79% in the methanolic extract and 85% in the hexane extract. Extracts have displayed effective reducing power and superoxide anion radical scavenging. Results of this study have highlighted potential antioxidant activity in the methanol and hexane extracts. The obtained results of the phytochemical screening showed the presence of terpenoids, flavonoids, phenols and saponins. The use of Cymbella as a natural antioxidant source and a potential source of antibacterial compounds and phytochemicals in the food industry appears promising and should be investigated further.

Keywords: antioxidants, antimicrobial, Cymbella, microalgae, phytochemicals

Procedia PDF Downloads 459

Authors: Abdelrahman Alghazali, Youssef Kassem, Hüseyin Çamur, Ozan Erenay

Abstract:

Savonius is a drag type vertical axis wind turbine. Savonius wind turbines have a low cut-in speed and can operate at low wind speed. This makes it suitable for electricity or mechanical generation in low-power applications such as individual domestic installations. Therefore, the primary purpose of this work was to investigate the relationship between the type of Savonius rotor and the torque and mechanical power generated. And it was to illustrate how the type of rotor might play an important role in the prediction of mechanical power of wind turbine powered car. The main purpose of this paper is to predict and investigate the aerodynamic effects by means of velocity analysis on the performance of a wind turbine powered car by converting the wind energy into mechanical energy to overcome load that rotates the main shaft. The predicted results based on theoretical analysis were compared with experimental results obtained from literature. The percentage of error between the two was approximately around 20%. Prediction of the torque was done at a wind speed of 4 m/s, and an angular velocity of 130 RPM according to meteorological statistics in Northern Cyprus.

Keywords: mechanical power, torque, Savonius rotor, wind car

Procedia PDF Downloads 340

Authors: Mehmet Alpaslan Köroğlu, Musa Hakan Arslan, Muslu Kazım Körez

Abstract:

Basic objective of this study is to create a regression analysis method that can estimate the length of a plastic hinge which is an important design parameter, by making use of the outcomes of (lateral load-lateral displacement hysteretic curves) the experimental studies conducted for the reinforced square concrete columns. For this aim, 170 different square reinforced concrete column tests results have been collected from the existing literature. The parameters which are thought affecting the plastic hinge length such as cross-section properties, features of material used, axial loading level, confinement of the column, longitudinal reinforcement bars in the columns etc. have been obtained from these 170 different square reinforced concrete column tests. In the study, when determining the length of plastic hinge, using the experimental test results, a regression analysis have been separately tested and compared with each other. In addition, the outcome of mentioned methods on determination of plastic hinge length of the reinforced concrete columns has been compared to other methods available in the literature.

Keywords: columns, plastic hinge length, regression analysis, reinforced concrete

Procedia PDF Downloads 482