Search results for: efficiency coefficient

Authors: Rabitah Zakaria, Chan M. Luan, Nor Hakimah Ramly

Abstract:

The extraction of vegetable oil using aqueous extraction process assisted by ionic extended surfactant has been investigated as an alternative to hexane extraction. However, the ionic extended surfactant has not been commercialised and its safety with respect to food processing is uncertain. Hence, food-grade non-ionic surfactants (Tween 20, Span 20, and Span 80) were proposed for the extraction of residual oil from palm-pressed mesocarp fibre. Palm-pressed mesocarp fibre contains a significant amount of residual oil ( 5-10 wt %) and its recovery is beneficial as the oil contains much higher content of vitamin E, carotenoids, and sterols compared to crude palm oil. In this study, the formulation of food-grade surfactants using a combination of high hydrophilic-lipophilic balance (HLB) surfactants and low HLB surfactants to produce micro-emulsion with very low interfacial tension (IFT) was investigated. The suitable surfactant formulation was used in the oil extraction process and the efficiency of the extraction was correlated with the IFT, droplet size and viscosity. It was found that a ternary surfactant mixture with a HLB value of 15 (82% Tween 20, 12% Span 20 and 6% Span 80) was able to produce micro-emulsion with very low IFT compared to other HLB combinations. Results suggested that the IFT and droplet size highly affect the oil recovery efficiency. Finally, optimization of the operating parameters shows that the highest extraction efficiency of 78% was achieved at 1:31 solid to liquid ratio, 2 wt % surfactant solution, temperature of 50˚C, and 50 minutes contact time.

Keywords: food-grade surfactants, aqueous extraction of residual oil, palm-pressed mesocarp fibre, interfacial tension

Procedia PDF Downloads 390

Authors: A. F. Huseynov, N. T. Mardanov, J. Y. Nakhchivanski

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This practical research is aimed to improve the management quality and efficiency of public administration agencies providing e-services. The monitoring system developed will provide continuous review of the websites compliance with the selected indicators, their evaluation based on the selected indicators and ranking of services according to the quality criteria. The responsible departments in the government agencies were surveyed; the questionnaire includes issues of management and feedback, e-services provided, and the application of information systems. By analyzing the main affecting factors and barriers, the recommendations will be given that lead to the relevant decisions to strengthen the state agencies competencies for the management and the provision of their services. Component 1. E-services monitoring system. Three separate monitoring activities are proposed to be executed in parallel: Continuous tracing of e-government sites using built-in web-monitoring program; this program generates several quantitative values which are basically related to the technical characteristics and the performance of websites. The expert assessment of e-government sites in accordance with the two general criteria. Criterion 1. Technical quality of the site. Criterion 2. Usability/accessibility (load, see, use). Each high-level criterion is in turn subdivided into several sub-criteria, such as: the fonts and the color of the background (Is it readable?), W3C coding standards, availability of the Robots.txt and the site map, the search engine, the feedback/contact and the security mechanisms. The on-line survey of the users/citizens – a small group of questions embedded in the e-service websites. The questionnaires comprise of the information concerning navigation, users’ experience with the website (whether it was positive or negative), etc. Automated monitoring of web-sites by its own could not capture the whole evaluation process, and should therefore be seen as a complement to expert’s manual web evaluations. All of the separate results were integrated to provide the complete evaluation picture. Component 2. Assessment of the agencies/departments efficiency in providing e-government services. - the relevant indicators to evaluate the efficiency and the effectiveness of e-services were identified; - the survey was conducted in all the governmental organizations (ministries, committees and agencies) that provide electronic services for the citizens or the businesses; - the quantitative and qualitative measures are covering the following sections of activities: e-governance, e-services, the feedback from the users, the information systems at the agencies’ disposal. Main results: 1. The software program and the set of indicators for internet sites evaluation has been developed and the results of pilot monitoring have been presented. 2. The evaluation of the (internal) efficiency of the e-government agencies based on the survey results with the practical recommendations related to the human potential, the information systems used and e-services provided.

Keywords: e-government, web-sites monitoring, survey, internal efficiency

Procedia PDF Downloads 304

Authors: Abhishek Priyam, Prabha Chand

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A theoretical investigation on the effect of collector aspect ratio on the thermal performance of wavy finned absorber solar air heaters has been performed. For the constant collector area, the various performance parameters have been calculated for plane and wavy finned solar air heaters. It has been found that the performance of wavy finned solar air heater improved with the increase in the collector aspect ratio. The performance of wavy finned solar air heater has been found 30 percent higher than those of plane solar air heater. The obtained results for wavy fin solar air heaters are compared with the available experimental data of most common type solar air heaters.

Keywords: wavy fin, aspect ratio, solar air heater, thermal efficiency, collector efficiency factor, temperature rise

Procedia PDF Downloads 329

Authors: Shima Naderi, Abbas Abbaszadeh Shahri

Abstract:

Energy resources are reachable and affordable in Iran, thus surplus access to fossil fuels besides high level of economic growth leads to serious environmental critical such as pollutants and greenhouse gases in the atmosphere, increase in average degrease and lack of water sources specially in Tehran as a capital city of Iran. As building sector consumes a huge portion of energy, taking actions towards alternative sources of energy as well as conserving non-renewable energy resources and architectural energy saving methods are the fundamental basis for achieving sustainability`s goals. This study tries to explore implantation of both high technologies and traditional issues for reduction of energy demands in buildings of Tehran and introduce some factors and instructions for achieving this purpose. Green and energy efficient buildings such as ZEBs make it possible to preserve natural resources for the next generations by reducing pollution and increasing ecosystem self-recovery. However ZEB is not widely spread in Iran because of its low economic efficiency, it is not viable for a private entrepreneur without the governmental supports. Therefore executing of Architectural Energy Efficiency can be a better option. It is necessary to experience a substructure expansion with respect to traditional residential building style. Renewable energies and passive design which are the substantial part of the history of architecture in Iran can be regenerated and employed as an essential part of designing energy efficient buildings.

Keywords: architectural energy efficiency, passive design, renewable energies, zero energy buildings

Procedia PDF Downloads 360

Authors: A. Ersan, A. S. Kipcak, M. Yildirim, A. M. Erayvaz, E. M. Derun, S. Piskin, N. Tugrul

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Zinc borates are used as a multi-functional flame retardant additive for its high dehydration temperature. In this study, a new method of ultrasonic mixing was used in the synthesis of zinc borates. The reactants of zinc oxide (ZnO) and boric acid (H3BO3) were used at the constant reaction parameters of 90°C reaction temperature and 55 min of reaction time. Several molar ratios of ZnO:H3BO3 (1:1, 1:2, 1:3, 1:4, and 1:5) were conducted for the determination of the optimum reaction ratio. Prior to the synthesis, the characterization of the synthesized zinc borates were made by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). From the results Zinc Oxide Borate Hydrate [Zn3B6O12.3.5H2O], were synthesized optimum at the molar ratio of 1:3, with a reaction efficiency of 95.2%.

Keywords: zinc borates, ultrasonic mixing, XRD, FT-IR, reaction efficiency

Procedia PDF Downloads 350

Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

Abstract:

With reference to Energy Roadmap 2050, the minimization of greenhouse gas emissions and the enhancement of energy efficiency are the two key factors that could facilitate a radical change in the world's energy infrastructure. However, the energy demands of electronic devices skyrocketed with the advent of the digital age. Currently, the two-phase cooling technique based on phase change pool boiling heat transfer has received a lot of attention because of its potential to fully utilize the latent heat of the fluid and produce a highly effective heat dissipation capacity while keeping the equipment's operating temperature within an acceptable range. There are numerous strategies available for the alteration of heating surfaces, but finding the best, simplest, and most dependable one remains a challenge. Lately, surface texturing via laser ablation has been used in a variety of investigations, demonstrating its significant potential for enhancing the pool boiling heat transfer performance. In this research, the nucleate pool boiling heat transfer performance of laser-structured copper surfaces of different patterns was investigated. The bare copper surface serves as a reference to compare the performance of laser-structured surfaces. It was observed that the heat transfer coefficients were increased with the increase of surface area ratio and the ratio of the peak-to-valley height of the microstructure. Laser machined grain structure produced extra nucleation sites, which ultimately caused the improved pool boiling performance. Due to an increase in nucleation site density and surface area, the enhanced nucleate boiling served as the primary heat transfer mechanism. The pool boiling performance of the laser-structured copper surfaces is superior to the bare copper surface in all aspects.

Keywords: heat transfer coefficient, laser structuring, micro structured surface, pool boiling

Procedia PDF Downloads 83

Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

Abstract:

With reference to Energy Roadmap 2050, the minimization of greenhouse gas emissions, and the enhancement of energy efficiency are the two key factors that could facilitate a radical change in the world's energy infrastructure. However, the energy demands of electronic devices skyrocketed with the advent of the digital age. Currently, the two-phase cooling technique based on phase change pool boiling heat transfer has received a lot of attention because of its potential to fully utilize the latent heat of the fluid and produce a highly effective heat dissipation capacity while keeping the equipment's operating temperature within an acceptable range. There are numerous strategies available for the alteration of heating surfaces, but to find the best, simplest, and most dependable one remains a challenge. Lately, surface texturing via laser ablation has been used in a variety of investigations, demonstrating its significant potential for enhancing the pool boiling heat transfer performance. In this research, the nucleate pool boiling heat transfer performance of laser-structured copper surfaces of different patterns was investigated. The bare copper surface serves as a reference to compare the performance of laser-structured surfaces. It was observed that the heat transfer coefficients were increased with the increase of surface area ratio and the ratio of the peak-to-valley height of the microstructure. Laser machined grain structure produced extra nucleation sites, which ultimately caused the improved pool boiling performance. Due to an increase in nucleation site density and surface area, the enhanced nucleate boiling served as the primary heat transfer mechanism. The pool boiling performance of the laser-structured copper surfaces is superior to the bare copper surface in all aspects.

Keywords: heat transfer coefficient, laser structuring, micro structured surface, pool boiling

Procedia PDF Downloads 81

Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md. Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

Abstract:

With reference to Energy Roadmap 2050, the minimization of greenhouse gas emissions and the enhancement of energy efficiency are the two key factors that could facilitate a radical change in the world's energy infrastructure. However, the energy demands of electronic devices skyrocketed with the advent of the digital age. Currently, the two-phase cooling technique based on phase change pool boiling heat transfer has received a lot of attention because of its potential to fully utilize the latent heat of the fluid and produce a highly effective heat dissipation capacity while keeping the equipment's operating temperature within an acceptable range. There are numerous strategies available for the alteration of heating surfaces, but to find the best, simplest, and most dependable one remains a challenge. Lately, surface texturing via laser ablation has been used in a variety of investigations, demonstrating its significant potential for enhancing the pool boiling heat transfer performance. In this research, the nucleate pool boiling heat transfer performance of laser-structured copper surfaces of different patterns was investigated. The bare copper surface serves as a reference to compare the performance of laser-structured surfaces. It was observed that the heat transfer coefficients were increased with the increase of surface area ratio and the ratio of the peak-to-valley height of the microstructure. Laser-machined grain structure produced extra nucleation sites, which ultimately caused the improved pool boiling performance. Due to an increase in nucleation site density and surface area, the enhanced nucleate boiling served as the primary heat transfer mechanism. The pool boiling performance of the laser-structured copper surfaces is superior to the bare copper surface in all aspects.

Keywords: heat transfer coefficient, laser structuring, micro structured surface, pool boiling

Procedia PDF Downloads 84

Authors: Omar Alhamad, Waleed Eid

Abstract:

Reinforced concrete is a concrete lined with steel so that the materials work together in the resistance forces. Reinforcement rods or mesh are used for tensile, shear, and sometimes intense pressure in a concrete structure. Reinforced concrete is subject to many natural problems or industrial errors. The result of these problems is that it reduces the efficiency of the reinforced concrete or its usefulness. Some of these problems are cracks, earthquakes, high temperatures or fires, as well as corrosion of reinforced iron inside reinforced concrete. There are also factors of ancient buildings or monuments that require some techniques to preserve them. This research presents some general information about reinforced concrete, the pros and cons of reinforced concrete, and then presents a series of literary studies of some of the late published researches on the subject of reinforced concrete and how to preserve it, propose solutions or treatments for the treatment of reinforced concrete problems, raise efficiency and quality for a longer period. These studies have provided advanced and modern methods and techniques in the field of reinforced concrete.

Keywords: reinforced concrete, treatment, concrete, corrosion, seismic, cracks

Procedia PDF Downloads 152

Authors: Guannan Ren, Thomas Mazzuchi, Shahram Sarkani

Abstract:

Electric vehicle battery recycling has emerged as a critical process in the transition toward sustainable transportation. As the demand for electric vehicles continues to rise, so does the need to address the end-of-life management of their batteries. Electric vehicle battery recycling benefits resource recovery and supply chain stability by reclaiming valuable metals like lithium, cobalt, nickel, and graphite. The reclaimed materials can then be reintroduced into the battery manufacturing process, reducing the reliance on raw material extraction and the environmental impacts of waste. Current battery recycling rates are insufficient to meet the growing demands for raw materials. While significant progress has been made in electric vehicle battery recycling, many areas can still improve. Standardization of battery designs, increased collection and recycling infrastructures, and improved efficiency in recycling processes are essential for scaling up recycling efforts and maximizing material recovery. This work delves into key factors, such as regulatory frameworks, economic incentives, and technological processes, that influence the cost-effectiveness and efficiency of battery recycling systems. A system dynamics model that considers variables such as battery production rates, demand and price fluctuations, recycling infrastructure capacity, and the effectiveness of recycling processes is created to study how these variables are interconnected, forming feedback loops that affect the overall supply chain efficiency. Such a model can also help simulate the effects of stricter regulations on battery disposal, incentives for recycling, or investments in research and development for battery designs and advanced recycling technologies. By using the developed model, policymakers, industry stakeholders, and researchers may gain insights into the effects of applying different policies or process updates on electric vehicle battery recycling rates.

Keywords: environmental engineering, modeling and simulation, circular economy, sustainability, transportation science, policy

Procedia PDF Downloads 92

Authors: Michael Gidey Gebru

Abstract:

Most of Data Envelopment Analysis models operate in a static environment with input and output parameters that are chosen by deterministic data. However, due to ambiguity brought on shifting market conditions, input and output data are not always precisely gathered in real-world scenarios. Fuzzy numbers can be used to address this kind of ambiguity in input and output data. Therefore, this work aims to expand crisp Data Envelopment Analysis into Data Envelopment Analysis with fuzzy environment. In this study, the input and output data are regarded as fuzzy triangular numbers. Then, the Data Envelopment Analysis model with fuzzy environment is solved using a multi-objective method to gauge the Decision Making Units' efficiency. Finally, the developed Data Envelopment Analysis model is illustrated with an application on real data 50 educational institutions.

Keywords: efficiency, Data Envelopment Analysis, fuzzy, higher education, input, output

Procedia PDF Downloads 57

Authors: Majid Yazdandoust

Abstract:

This study, tries to suggest a design method based on displacement using finite difference numerical modeling in reinforcing soil retaining wall with steel strip. In this case, dynamic loading characteristics such as duration, frequency, peak ground acceleration, geometrical characteristics of reinforced soil structure and type of the site are considered to correct the pseudo static method and finally introduce the pseudo static coefficient as a function of seismic performance level and peak ground acceleration. For this purpose, the influence of dynamic loading characteristics, reinforcement length, height of reinforced system and type of the site are investigated on seismic behavior of reinforcing soil retaining wall with steel strip. Numerical results illustrate that the seismic response of this type of wall is highly dependent to cumulative absolute velocity, maximum acceleration, and height and reinforcement length so that the reinforcement length can be introduced as the main factor in shape of failure. Considering the loading parameters, mechanically stabilized earth wall parameters and type of the site showed that the used method in this study leads to most efficient designs in comparison with other methods which are generally suggested in cods that are usually based on limit-equilibrium concept. The outputs show the over-estimation of equilibrium design methods in comparison with proposed displacement based methods here.

Keywords: pseudo static coefficient, seismic performance design, numerical modeling, steel strip reinforcement, retaining walls, cumulative absolute velocity, failure shape

Procedia PDF Downloads 485

Authors: Mahmoud Y. Shokry, Rami M. El-Sherbiny

Abstract:

This paper aims to highlight the role of some parameters that may be of a noticeable impact on numerical analysis/design of embankments. It presents the results of a three-dimensional (3-D) finite element analysis of a monitored earth embankment that was constructed on soft clay formation stabilized by cast in-situ piles using software PLAXIS 3D. A comparison between the predicted and the monitored responses is presented to assess the adequacy of the adopted numerical model. The model was used in the targeted parametric study. Moreover, a comparison was performed between the results of the 3-D analyses and the analytical solutions. This paper concluded that the effect of using mono pile caps led to decrease both the total and differential settlement and increased the efficiency of the piled embankment system. The study of using geogrids revealed that it can contribute in decreasing the settlement and maximizing the part of the embankment load transferred to piles. Moreover, it was found that increasing the stiffness of the geogrids provides higher values of tensile forces and hence has more effective influence on embankment load carried by piles rather than using multi-number of layers with low values of geogrid stiffness. The efficiency of the piled embankments system was also found to be greater when higher embankments are used rather than the low height embankments. The comparison between the numerical 3-D model and the theoretical design methods revealed that many analytical solutions are conservative and non-accurate rather than the 3-D finite element numerical models.

Keywords: efficiency, embankment, geogrids, soft clay

Procedia PDF Downloads 323

Authors: Tunahan Sapmaz, Harun Etçi, İbrahim Şenol, Yasemin Öner

Abstract:

Rotor bar dimensions have a great influence on the air-gap magnetic flux density. Therefore, poor selection of this parameter during the machine design phase causes the air-gap magnetic flux density to be distorted. Thus, it causes noise, torque fluctuation, and losses in the induction motor. On the other hand, the change in rotor bar dimensions will change the resistance of the conductor, so the current will be affected. Therefore, the increase and decrease of rotor bar current affect operation, starting torque, and efficiency. The aim of this study is to examine the effect of rotor bar dimensions on the electromagnetic performance criteria of the induction motor. Modeling of the induction motor is done by the finite element method (FEM), which is a very powerful tool. In FEM, the results generally focus on performance criteria such as torque, torque fluctuation, efficiency, and current.

Keywords: induction motor, finite element method, optimization, rotor bar

Procedia PDF Downloads 126

Authors: Guillaume Schuchardt, Solenn Berson, Gerard Perrier

Abstract:

Multi-junction solar cell configurations, where two sub-cells with complementary absorption are stacked and connected in series, offer an exciting approach to tackle the single junction limitations of organic solar cells and improve their power conversion efficiency. However, the augmentation of the number of layers has, as a consequence, to increase the risk of reducing the lifetime of the cell due to the ageing phenomena present at the interfaces. In this work, we study the intrinsic degradation mechanisms, under continuous illumination AM1.5G, inert atmosphere and room temperature, in single and tandem organic solar cells using Impedance Spectroscopy, IV Curves, External Quantum Efficiency, Steady-State Photocarrier Grating, Scanning Kelvin Probe and UV-Visible light.

Keywords: single and tandem organic solar cells, intrinsic degradation mechanisms, characterization: SKP, EQE, SSPG, UV-Visible, Impedance Spectroscopy, optical simulation

Procedia PDF Downloads 362

Authors: Enes Yasa, Guven Fidan

Abstract:

Building Simulation tools need to better evaluate convective heat exchanges between external air and wall surfaces. Previous analysis demonstrated the significant effects of convective heat transfer coefficient values on the room energy balance. Some authors have pointed out that large discrepancies observed between widely used building thermal models can be attributed to the different correlations used to calculate or impose the value of the convective heat transfer coefficients. Moreover, numerous researchers have made sensitivity calculations and proved that the choice of Convective Heat Transfer Coefficient values can lead to differences from 20% to 40% of energy demands. The thermal losses to the ambient from a building surface or a roof mounted solar collector represent an important portion of the overall energy balance and depend heavily on the wind induced convection. In an effort to help designers make better use of the available correlations in the literature for the external convection coefficients due to the wind, a critical discussion and a suitable tabulation is presented, on the basis of algebraic form of the coefficients and their dependence upon characteristic length and wind direction, in addition to wind speed. Many research works have been conducted since early eighties focused on the convection heat transfer problems inside buildings. In this context, a Computational Fluid Dynamics (CFD) program has been used to predict external convective heat transfer coefficients at external building surfaces. For the building facades model, effects of wind speed and temperature differences between the surfaces and the external air have been analyzed, showing different heat transfer conditions and coefficients. In order to provide further information on external convective heat transfer coefficients, a numerical work is presented in this paper, using a Computational Fluid Dynamics (CFD) commercial package (CFX) to predict convective heat transfer coefficients at external building surface.

Keywords: CFD in buildings, external convective heat transfer coefficients, building facades, thermal modelling

Procedia PDF Downloads 421

Authors: Román Rodríguez Echegoyen, Fernando Carlos López Hernández, José Manuel López Ujaque

Abstract:

Interactive management of energy certification ratings has remained on the sidelines of the evolution of virtual reality (VR) despite related advances in architecture in other areas such as BIM and real-time working programs. This research studies to what extent VR software can help the stakeholders to better understand energy efficiency parameters in order to obtain reliable ratings assigned to the parts of the building. To evaluate this hypothesis, the methodology has included the construction of a software prototype. Current energy certification systems do not follow an intuitive data entry system; neither do they provide a simple or visual verification of the technical values included in the certification by manufacturers or other users. This software, by means of real-time visualization and a graphical user interface, proposes different improvements to the current energy certification systems that ease the understanding of how the certification parameters work in a building. Furthermore, the difficulty of using current interfaces, which are not friendly or intuitive for the user, means that untrained users usually get a poor idea of the grounds for certification and how the program works. In addition, the proposed software allows users to add further information, such as financial and CO₂ savings, energy efficiency, and an explanatory analysis of results for the least efficient areas of the building through a new visual mode. The software also helps the user to evaluate whether or not an investment to improve the materials of an installation is worth the cost of the different energy certification parameters. The evaluated prototype (named VEE-IS) shows promising results when it comes to representing in a more intuitive and simple manner the energy rating of the different elements of the building. Users can also personalize all the inputs necessary to create a correct certification, such as floor materials, walls, installations, or other important parameters. Working in real-time through VR allows for efficiently comparing, analyzing, and improving the rated elements, as well as the parameters that we must enter to calculate the final certification. The prototype also allows for visualizing the building in efficiency mode, which lets us move over the building to analyze thermal bridges or other energy efficiency data. This research also finds that the visual representation of energy efficiency certifications makes it easy for the stakeholders to examine improvements progressively, which adds value to the different phases of design and sale.

Keywords: energetic certification, virtual reality, augmented reality, sustainability

Procedia PDF Downloads 186

Authors: Yasser M. Saad, Heba El-Sebaie Abd El-Sadek

Abstract:

Some Metapenaeus monoceros cox1 gene fragments were isolated, purified, sequenced, and comparatively analyzed with some other Crustacean Cox1 gene sequences (obtained from National Center for Biotechnology Information). This work was designed for testing the efficiency of this system in reconstruction of phylogenetic relations among some Crustacean species belonging to four genera (Metapenaeus, Artemia, Daphnia and Calanus). The single nucleotide polymorphism and haplotype diversity were calculated for all estimated mt-DNA fragments. The genetic distance values were 0.292, 0.015, 0.151, and 0.09 within Metapenaeus species, Calanus species, Artemia species, and Daphnia species, respectively. The reconstructed phylogenetic tree is clustered into some unique clades. Cytochrome oxidase subunit 1 gene (cox1) was a powerful system in reconstruction of phylogenetic relations among evaluated crustacean species.

Keywords: crustaceans, genetics, Cox1, phylogeny

Procedia PDF Downloads 362

Authors: Waratthaya Maneerattana, Piyarat Dornbundit

Abstract:

The study aimed to develop flipped classroom in Chemistry on ‘acid-base’ for high school students and study efficiency of students on academic achievement and problem-solving skills. The evaluating result from the experts showed that developed flipped classroom was ranked in high score level. The flipped classroom efficiency E1/E2 was higher than the criteria of 70/70. The flipped classroom was used by 24 students in grade 11 in the second semester of the academic year 2016 at Bodindecha (Sing Singhaseni) School. Sampling group was chosen using a purposive sampling approach. The results revealed that academic achievement and problem solving skills of students after studying flipped classroom was significantly higher at .05 level.

Keywords: flipped classroom, acid-base, academic achievement, problem solving skill

Procedia PDF Downloads 314

Authors: Funda Buyuk Mazari, Adnan Mazari, Antonin Havelka, Jakub Wiener, Jawad Naeem

Abstract:

The use of super absorbent polymers (SAP) for moisture absorption and comfort is still unexplored. In this research the efficiency of different SAP fibrous webs are determined under different moisture percentage to examine the sorption and desorption efficiency. The SAP fibrous web with low thickness and high moisture absorption are tested with multilayer sandwich structure of car seat cover to determine the moisture absorption through cover material. Sweating guarded hot plate (SGHP) from company Atlas is used to determine the moisture permeability of different car seat cover with superabsorbent layer closed with impermeable polyurethane foam. It is observed that the SAP fibrous layers are very effective in absorbing and desorbing water vapor under extreme high and low moisture percentages respectively. In extreme humid condition (95 %RH) the 20g of SAP layer absorbs nearly 3g of water vapor per hour and reaches the maximum absorption capacity in 6 hours.

Keywords: car seat, comfort, SAF, superabsorbent

Procedia PDF Downloads 475

Authors: Yoftahe Nigussie

Abstract:

This research explores the implementation of a vapor absorption refrigeration system (VARS) in mini-bus cars to enhance air conditioning efficiency. The conventional vapor compression refrigeration system (VCRS) in vehicles relies on mechanical work from the engine, leading to increased fuel consumption. The proposed VARS aims to utilize waste heat and exhaust gas from the internal combustion engine to cool the mini-bus cabin, thereby reducing fuel consumption and atmospheric pollution. The project involves two models: Model 1, a two-fluid vapor absorption system (VAS), and Model 2, a three-fluid VAS. Model 1 uses ammonia (NH₃) and water (H₂O) as refrigerants, where water absorbs ammonia rapidly, producing a cooling effect. The absorption cycle operates on the principle that absorbing ammonia in water decreases vapor pressure. The ammonia-water solution undergoes cycles of desorption, condensation, expansion, and absorption, facilitated by a generator, condenser, expansion valve, and absorber. The objectives of this research include reducing atmospheric pollution, minimizing air conditioning maintenance costs, lowering capital costs, enhancing fuel economy, and eliminating the need for a compressor. The comparison between vapor absorption and compression systems reveals advantages such as smoother operation, fewer moving parts, and the ability to work at lower evaporator pressures without affecting the Coefficient of Performance (COP). The proposed VARS demonstrates potential benefits for mini-bus air conditioning systems, providing a sustainable and energy-efficient alternative. By utilizing waste heat and exhaust gas, this system contributes to environmental preservation while addressing economic considerations for vehicle owners. Further research and development in this area could lead to the widespread adoption of vapor absorption technology in automotive air conditioning systems.

Keywords: room, zone, space, thermal resistance

Procedia PDF Downloads 70

Authors: Natalya G. Filimonova, Mariya G. Ozerova, Irina N. Ermakova

Abstract:

The long-term strategy of the economic development of Russia up to 2030 is based on the concept of sustainable growth. The determining factor of such development is complex changes in the economic system which may be achieved by making progressive changes in its structure. The structural changes determine the character and the direction of economic development, as well as they include all elements of this system without exception, and their regulated character ensures the most rapid aim achievement. This article has discussed the industrial structure of the agriculture in Russia. With the use of the system of indexes, the article has determined the directions, intensity, and speed of structural shifts. The influence of structural changes on agricultural production development has been found out. It is noticed that the changes in the industrial structure are synchronized with the changes in the organisation and economic structure. Efficiency assessment of structural changes allowed to trace the efficiency of structural changes and elaborate the main directions for agricultural policy improvement.

Keywords: Russian agricultural sectors, sectoral structure, organizational and economic structure, structural changes

Procedia PDF Downloads 170

Authors: Nasrin Hosseinzad, Ramin Ghasemi Shayan

Abstract:

Chemotherapy is the most common procedure in the treatment of advanced cancers but is justsoberlyoperativeand toxic. Nevertheless, the efficiency of chemotherapy is restrictedowing to multiple drug resistance(MDR). Lately, plentiful preclinical experiments have revealedthatPaclitaxel-Curcumin could be an ultimateapproach to converse MDR and synergistically increase their efficiency. The connotationsamongst B-cell-lymphoma2(BCL-2) and multi-drug-resistance-associated-P-glycoprotein(MDR1) consequence of patients forecast the efficiency of paclitaxel-built chemoradiotherapy. There are evidences of the efficacy of paclitaxel in the treatment of surface-transmission of bladder-cell-carcinoma by manipulating bio-adhesive microspheres accomplishedthroughout measured release of drug at urine epithelium. In Genetically-Modified method, muco-adhesive oily constructionoftricaprylin, Tween 80, and paclitaxel group showed slighter toxicity than control in therapeutic dose. Postoperative chemotherapy-Paclitaxel might be more advantageous for survival than adjuvant chemo-radio-therapy, and coulddiminish postoperative complications in cervical cancer patients underwent a radical hysterectomy.HA-Se-PTX(Hyaluronic acid, Selenium, Paclitaxel) nanoparticles could observablyconstrain the proliferation, transmission, and invasion of metastatic cells and apoptosis. Furthermore, they exhibitedvast in vivo anti-tumor effect. Additionally, HA-Se-PTX displayedminor toxicity on mice-chef-organs. Briefly, HA-Se-PTX mightprogress into a respectednano-scale agentinrespiratory cancers. To sum up, Paclitaxel is considered a profitable anti-cancer drug in the treatment and anti-progress symptoms in malignant cancers.

Keywords: cancer, paclitaxel, chemotherapy, tumor

Procedia PDF Downloads 132

Authors: A. D. Parekh, P. R. Tailor

Abstract:

The Montreal protocol and Kyoto protocol underlined the need of substitution of CFC’s and HCFC’s due to their adverse impact on atmospheric ozone layer which protects earth from U.V rays. The CFCs have been entirely ruled out since 1995 and a long-term basis HCFCs must be replaced by 2020. All this events motivated HFC refrigerants which are harmless to ozone layer. In this paper thermodynamic analysis of cascade refrigeration system has been done using three different refrigerant pairs R13-R12, R290-R23, and R404A-R23. Effect of various operating parameters i.e evaporator temperature, condenser temperature, temperature difference in cascade condenser and low temperature cycle condenser temperature on performance parameters viz. COP, exergetic efficiency and refrigerant mass flow ratio have been studied. Thermodynamic analysis shows that out of three refrigerant pairs R12-R13, R290-R23 and R404A-R23 the COP of R290-R23 refrigerant pair is highest.

Keywords: thermodynamic analysis, cascade refrigeration system, COP, exergetic efficiency

Procedia PDF Downloads 297

Authors: Rituparna Pal, Faiz Ahmed

Abstract:

Neighbourhood energy efficiency is a newly emerged term to address the quality of urban strata of built environment in terms of various covariates of sustainability. The concept of sustainability paradigm in developed nations has encouraged the policymakers for developing urban scale cities to envision plans under the aegis of urban scale sustainability. The concept of neighbourhood energy efficiency is realized a lot lately just when the cities, towns and other areas comprising this massive global urban strata have started facing a strong blow from climate change, energy crisis, cost hike and an alarming shortfall in the justice which the urban areas required. So this step of urban sustainability can be easily referred more as a ‘Retrofit Action’ which is to cover up the already affected urban structure. So even if we start energy efficiency for existing cities and urban areas the initial layer remains, for which a complete model of urban sustainability still lacks definition. Urban sustainability is a broadly spoken off word with end number of parameters and policies through which the loop can be met. Out of which neighbourhood energy efficiency can be an integral part where the concept and index of neighbourhood scale indicators, block level indicators and building physics parameters can be understood, analyzed and concluded to help emerge guidelines for urban scale sustainability. The future of neighbourhood energy efficiency not only lies in energy efficiency but also important parameters like quality of life, access to green, access to daylight, outdoor comfort, natural ventilation etc. So apart from designing less energy-hungry buildings, it is required to create a built environment which will create less stress on buildings to consume more energy. A lot of literary analysis has been done in the Western countries prominently in Spain, Paris and also Hong Kong, leaving a distinct gap in the Indian scenario in exploring the sustainability at the urban strata. The site for the study has been selected in the upcoming capital city of Amaravati which can be replicated with similar neighbourhood typologies in the area. The paper suggests a methodical intent to quantify energy and sustainability indices in detail taking by involving several macro, meso and micro level covariates and parameters. Several iterations have been made both at macro and micro level and have been subjected to simulation, computation and mathematical models and finally to comparative analysis. Parameters at all levels are analyzed to suggest the best case scenarios which in turn is extrapolated to the macro level finally coming out with a proposal model for energy efficient neighbourhood and worked out guidelines with significance and correlations derived.

Keywords: energy quantification, macro scale parameters, meso scale parameters, micro scale parameters

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Authors: Gagik Ayvazyan, Levon Hakhoyan, Surik Khudaverdyan, Laura Lakhoyan

Abstract:

Black Si (b-Si) is a nano-structured Si surface formed by a self-organized, maskless process with needle-like surfaces discernible by their black color. The combination of low reflectivity and the semi-conductive properties of Si found in b-Si make it a prime candidate for application in solar cells as an antireflection surface. However, surface recombination losses significantly reduce the efficiency of b-Si solar cells. Surface passivation using suitable dielectric films can minimize these losses. Nowadays some works have demonstrated that excellent passivation of b-Si nanostructures can be reached using Al₂O₃ films. However, the negative fixed charge present in Al₂O₃ films should provide good field effect passivation only for p- and p+-type Si surfaces. HfO2 thin films have not been practically tested for passivation of b-Si. HfO₂ could provide an alternative for n- and n+- type Si surface passivation since it has been shown to exhibit positive fixed charge. Using optical simulation by Finite-Difference Time Domain (FDTD) method, the possibility of b-Si passivation by HfO2 films has been analyzed. The FDTD modeling revealed that b-Si layers with HfO₂ films effectively suppress reflection in the wavelength range 400–1000 nm and across a wide range of incidence angles. The light-trapping performance primarily depends on geometry of the needles and film thickness. With the decrease of periodicity and increase of height of the needles, the reflectance decrease significantly, and the absorption increases significantly. Increase in thickness results in an even greater decrease in the calculated reflection coefficient of model structures and, consequently, to an improvement in the antireflection characteristics in the visible range. The excellent surface passivation and low reflectance results prove the potential of using the combination of the b-Si surface and the HfO₂ film for solar cells applications.

Keywords: antireflection, black silicon, HfO₂, passivation, simulation, solar cell

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Authors: Zeynep Aytaç, Nuri Yücel

Abstract:

Today, as the need for high efficiency and fuel-efficient engines have increased, centrifugal compressor designs are expected to be high-efficient and have high-pressure ratios than ever. The present study represents a design methodology of centrifugal compressor placed in a mini jet engine for the design and off-design points with the utilization of computational fluid dynamics (CFD) and compares the performance characteristics at the mentioned two points. Although the compressor is expected to provide the required specifications at the design point, it is known that it is important for the design to deliver the required parameters at the off-design point also as it will not operate at the design point always. It was observed that the obtained mass flow rate, pressure ratio, and efficiency values are within the limits of the design specifications for the design and off-design points. Despite having different design inputs for the mentioned two points, they reveal similar flow characteristics in the general frame.

Keywords: centrifugal compressor, computational fluid dynamics, design point, off-design point

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Authors: Eugene Rybin

Abstract:

Reduction of nutrient losses when using mineral fertilizers is a very important and urgent challenge, which is of both economic and environmental significance. This paper shows the production of slow- and controlled release fertilizers through application of inorganic coatings, which make the released nutrients plant-available. The method of production of coated fertilizers with inorganic cover material is an alternative to other methods where polymer coatings are used. The method is based on spraying an aqueous slurry onto the surface of granules with simultaneous drying in drums under certain conditions and subsequent cooling of granules. This method of production of slow- and controlled-release fertilizers is more ecofriendly compared with others because inorganic materials are used to create a membrane. That is why the coating material is definitely biodegradable. There is also shown the effect of these coatings on the properties of fertilizers, as well as on the agrochemical efficiency and nutrient efficiency/ availability to the plants. The agrochemical tests have proved the increase of nutrient efficiency for every nutrient in compound fertilizers (NPK, NPS) for 3 consecutive years by 10-20 % and by 25-28% for urea, as well as an increase in crop yield, by 10-15% in general, and its quality. Moreover, the decrease in caking by almost 70% was proven as well as slowing down the release rate of nutrients from fertilizers. Control of the release rate was achieved by regulation of thickness and contents of coating materials. All of those characteristics were researched according to the standard-used methods. The performed research has developed the fertilizer technology of slow- and controlled release of nutrients through applying of plant-available inorganic coatings. It leads to a better synchronization of nutrient release rate and plants needs, as well as reduces the harmful effects on the environment from the fertilizers applied.

Keywords: controlled release, fertilizers, nutrients, plant-available coatings

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Authors: Rizwan Ahmad, Soomin Chang, Daeun Kwon, Jeonghwan Kim

Abstract:

Interests in an inorganic membrane are growing rapidly for industrial wastewater treatment due to its excellent chemical and thermal stability over polymeric membrane. Nevertheless, understanding of the membrane rejection and fouling rate caused by the deposit of contaminants on membrane surface and within membrane pores through inorganic porous membranes still requires much attention. Microfiltration alumina membranes were developed and applied for the industrial wastewater treatment to investigate rejection efficiency of organic contaminant and membrane fouling at various operational conditions. In this study, organic rejection and membrane fouling were investigated by using the alumina flat-tubular membrane developed for the treatment of industrial wastewaters. The flat-tubular alumina membranes were immersed in a fluidized membrane reactor added with granular activated carbon (GAC) particles. Fluidization was driven by recirculating a bulk industrial wastewater along membrane surface through the reactor. In the absence of GAC particles, for hazardous anionic dye contaminants, functional group characterized by the organic contaminant was found as one of the main factors affecting both membrane rejection and fouling rate. More fouling on the membrane surface led to the existence of dipolar characterizations and this was more pronounced at lower solution pH, thereby improving membrane rejection accordingly. Similar result was observed with a real metal-plating wastewater. Strong correlation was found that higher fouling rate resulted in higher organic rejection efficiency. Hydrophilicity exhibited by alumina membrane improved the organic rejection efficiency of the membrane due to the formation of hydrophilic fouling layer deposited on it. In addition, less surface roughness of alumina membrane resulted in less fouling rate. Regardless of the operational conditions applied in this study, fluidizing the GAC particles along the surface of alumina membrane was very effective to enhance organic removal efficiency higher than 95% and provide an excellent tool to reduce membrane fouling. Less than 0.1 bar as suction pressure was maintained with the alumina membrane at 25 L/m²hr of permeate set-point flux during the whole operational periods without performing any backwashing and chemical enhanced cleaning for the membrane.

Keywords: alumina membrane, fluidized membrane reactor, industrial wastewater, membrane fouling, rejection

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Authors: Yu-Jen Shih, Yao-Hui Hunag

Abstract:

Electrocoagulation (EC) using metallic nickel foam as anode and cathode for the removal of boron from solution was studied. The electrolytic parameters included pH, current density, and initial boron concentration for optimizing the EC process. Experimental results showed that removal efficiency was increased by elevating pH from 4.0 to 8.0, and then decreased at higher pH. The electrolytic efficacy was not affected by current density. In respect of energy consumption, 1.25 mA/cm2 of current density was acceptable for an effective EC of boron, while increasing boric acid from 10 to 100 ppm-B did not impair removal efficiency too much. Cyclic voltammetry indicated that the oxide film, Ni(OH)2 and NiOOH, at specific overpotentials would result in less weight loss of anode than that predicted by the Faraday’s law. The optimal conditions under which 99.2% of boron was removed and less than 1 ppm-B remained in the electrolyte would be pH 8, four pairs of electrodes, and 1.25 mA/cm2 in 120 min as treating wastewaters containing 10 ppm-B. XRD and SEM characterization suggested that the granular crystallites of hydroxide precipitates was composed of theophrastite.

Keywords: borohydrides, hydrogen generation, NiOOH, electrocoagulation, cyclic voltammetry, boron removal

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