Search results for: internal heat sources

Authors: Saul A. Torres Z., Eduardo Liceaga C., Alfredo Arias M.

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Agriculture in the world falls within the main sources of economic and global needs, so care of crop is extremely important for owners and workers; one of the major causes of loss of product is the pest infection of different types of organisms. We seek to develop a UAV for agricultural spraying at a maximum altitude of 5000 meters above sea level, with a payload of 100 liters of fumigant. For the developing the aerodynamic design of the aircraft is using computational tools such as the "Vortex Lattice Athena" software, "MATLAB"," ANSYS FLUENT"," XFoil " package among others. Also methods are being used structured programming, exhaustive analysis of optimization methods and search. The results have a very low margin of error, and the multi- objective problems can be helpful for future developments. The program has 10 functions developed in MATLAB, these functions are related to each other to enable the development of design, and all these functions are controlled by the principal code "Master.m".

Keywords: aerodynamics design, optimization, algorithm genetic, multi-objective problem, stability, vortex

Procedia PDF Downloads 532

Authors: Natalia Muratova, Dmitry Klimov, Rafail Isemin, Sergey Kuzmin, Aleksandr Mikhalev, Oleg Milovanov

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We investigated the processing of poultry litter into biochar using dry torrefaction methods (DT) in a fixed and fluidized bed of quartz sand blown with nitrogen, as well as wet torrefaction (WT) in a fluidized bed in a medium of water steam at a temperature of 300 °C. Torrefaction technology affects the duration of the heat treatment process and the characteristics of the biochar: the process of separating CO₂, CO, H₂ and CH₄ from a portion of fresh poultry litter during torrefaction in a fixed bed is completed after 2400 seconds, but in a fluidized bed — after 480 seconds. During WT in a fluidized bed of quartz sand, this process ends in 840 seconds after loading a portion of fresh litter, but in a fluidized bed of litter particles previously subjected to torrefaction, the process ends in 350 - 450 seconds. In terms of the ratio between (H/C) and (O/C), the litter obtained after DT and WT treatment corresponds to lignite. WT in a fluidized bed allows one to obtain biochar, in which the specific pore area is two times larger than the specific pore area of biochar obtained after DT in a fluidized bed. Biochar, obtained as a result of the poultry litter treatment in a fluidized bed using DT or WT method, is recommended to be used not only as a biofuel but also as an adsorbent or the soil fertilizer.

Keywords: biochar, poultry litter, dry and wet torrefaction, fixed bed, fluidized bed

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Authors: Farid Arya, Trevor Hyde, Paul Henshall, Phillip Eames, Roger Moss, Stan Shire

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Vacuum flat plate solar thermal collectors offer several advantages over other collectors namely the excellent optical and thermal characteristics they exhibit due to a combination of their wide surface area and high vacuum thermal insulation. These characteristics can offer a variety of applications for industrial process heat as well as for building integration as they are much thinner than conventional collectors making installation possible in limited spaces. However, many technical challenges which need to be addressed to enable wide scale adoption of the technology still remain. This paper will discuss the challenges, expectations and requirements for the flat-plate vacuum solar collector development. In addition, it will provide an overview of work undertaken in Ulster University, Loughborough University, and the University of Warwick on flat-plate vacuum solar thermal collectors. Finally, this paper will present a detailed experimental investigation on the development of a vacuum panel with a novel sealing method which will be used to accommodate a novel slim hydroformed solar absorber.

Keywords: hot box calorimeter, infrared thermography, solar thermal collector, vacuum insulation

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Authors: Jui-Chen Huang, Shou-Hsiung Cheng

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This study examined their willingness to use telecare for people who have had experience falling in the last three months in Taiwan. This study adopted convenience sampling and a structural questionnaire to collect data. It was based on the definition and the constructs related to the Health Belief Model (HBM). HBM is comprised of seven constructs: perceived benefits (PBs), perceived disease threat (PDT), perceived barriers of taking action (PBTA), external cues to action (ECUE), internal cues to action (ICUE), attitude toward using (ATT), and behavioral intention to use (BI). This study adopted Fuzzy Neural Network (FNN) to put forward an effective method. It shows the dependence of ATT on PB, PDT, PBTA, ECUE, and ICUE. The training and testing data RMSE (root mean square error) are 0.028 and 0.166 in the FNN, respectively. The training and testing data RMSE are 0.828 and 0.578 in the regression model, respectively. On the other hand, as to the dependence of ATT on BI, as presented in the FNN, the training and testing data RMSE are 0.050 and 0.109, respectively. The training and testing data RMSE are 0.529 and 0.571 in the regression model, respectively. The results show that the FNN method is better than the regression analysis. It is an effective and viable good way.

Keywords: fall, fuzzy neural network, health belief model, telecare, willingness

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Authors: Cecilia Kunseh Betek

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Managing rural water supply systems effectively and efficiently is a challenge in the O R Tambo District Municipality due to the long distances between consumers and municipal centres. This is a couple with the low income of most residents and the government's policy of free basic water which is making rural water provision very difficult. With regard to cartage, the results reveal that the majority (84.4%) of the population covers distances of about 1kilometre to fetch water, and 15.6% travel up kilometer to access water facilities. This means that the water sources are located very far from households, outside the officially legislated array of 200metres. These are many reasons to account for this situation. Firstly, this implies that there are inadequate stand pipes to cater for all the homesteads scattered across the rugged terrain of OR Tambo District municipality. Secondly, and following from the first explanation, it would be seen that funding that is made available is not adequate, or is not efficiently spent on the targeted projects. The situation in the rural areas of South Africa is fraught with cumbersome complexity when it comes to service delivery.

Keywords: water, management, government, rural

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Authors: Hanbey Hazar, Hakan Gul, Ugur Ozturk

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In order to decrease the hazardous emissions of the internal combustion engines and to improve the combustion and thermal efficiency, thermal barrier coatings are applied. In this experimental study, cylinder, piston, exhaust, and inlet valves which are combustion chamber components have been coated with a ceramic material, and this earned the engine LHR feature. Cylinder, exhaust and inlet valves of the diesel engine used in the tests were coated with ekabor-2 commercial powder, which is a ceramic material, to a thickness of 50 µm, by using the boriding method. The piston of a diesel engine was coated in 300 µm thickness with bor-based powder by using plasma coating method. Pumpkin seeds oil methyl ester (PSME) was produced by the transesterification method. In addition, dimethoxymethane additive materials were used to improve the properties of diesel fuel, pumpkin seeds oil methyl ester (PSME) and its mixture. Dimethoxymethane was blended with test fuels, which was used as a pilot fuel, at the volumetric ratios of 4% and 8%. Due to thermal barrier coating, the diesel engine's CO, HC, and smoke density values decreased; but, NOx and exhaust gas temperature (EGT) increased.

Keywords: boriding, diesel engine, exhaust emission, thermal barrier coating

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Authors: Abdulmagid A. Khattabi, Ahmed A. Hablus, Osama Ab. M. Shafah

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The goal of this work is to understand how the thermal influence of combustion chamber deposits can be utilized to expand the operating range of HCCI combustion. In order to do this, two main objectives must first be met; tracking deposit formation trends in an HCCI engine and determining the sensitivity of HCCI combustion to CCD. This requires testing that demonstrates the differences in combustion between a clean engine and one with deposits coating the chamber. This will involve a long-term test that tracks the effects of CCD on combustion. The test will start with a clean engine. One baseline HCCI operating point is maintained for the duration of the test during which gradual combustion chamber deposit formation will occur. Combustion parameters, including heat release rates and emissions will be tracked for the duration and compared to the case of a clean engine. This work will begin by detailing the specifics of the test procedure and measurements taken throughout the test. Then a review of the effects of the gradual formation of deposits in the engine will be given.

Keywords: fuels, fuel atomization, pattern factor, alternate fuels combustion, efficiency gas turbine combustion, lean blow out, exhaust and liner wall temperature

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Authors: Yogesh Shukla

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Many attempts have been made to study temperature distribution problem in human tissues under normal environmental and physiological conditions at constant arterial blood temperature. But very few attempts have been made to investigate temperature distribution in human tissues under different arterial blood temperature. In view of above, a finite element model has been developed to unsteady temperature distribution in dermal region in human body. The model has been developed for one dimension unsteady state case. The variation in parameters like thermal conductivity, blood mass flow and metabolic activity with respect to position and time has been incorporated in the model. Appropriate boundary conditions have been framed. The central difference approach has been used in space variable and trapezoidal rule has been employed a long time variable. Numerical results have been obtained to study relationship among temperature and time.

Keywords: rate of metabolism, blood mass flow rate, thermal conductivity, heat generation, finite element method

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Authors: M. Safiqul Islam, Md Arafat Hossain Sarkar

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Brachytherapy is one of the most important cancer treatment management systems in radiotherapy department. Brachytherapy treatment is moved into High Dose Rate (HDR) after loader from Low Dose Rate (LDR) after loader due to radiation protection advantage. HDR Brachytherapy is a highly multipurpose system for enhancing cure and achieving palliation in many common cancers disease of developing countries. High-dose rate (HDR) Brachytherapy is a type of internal radiation therapy that delivers radiation from implants placed close to or inside, the tumor(s) in the body. This procedure is very effective at providing localized radiation to the tumor site while minimizing the patient’s whole body dose. Brachytherapy has proven to be a highly successful treatment for cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck, as well as soft tissue sarcomas and several other types of cancer. For the time being in our country we have 10 new HDR Remote after loading Brachytherapy. Right now 4 HDR Brachytherapy is already installed and running for patient’s treatment out of 10 HDR Brachytherapy. Ir-192 source is more comfortable than Co-60. In that case people or expert personnel prefer Ir-192 source for different kind of cancer patients. Ir-192 are economically, more flexible and familiar in our country.

Keywords: Ir-192, brachytherapy, cancer treatment, prostate, cervix, endometrium, breast, skin, bronchus, esophagus, soft tissue sarcomas

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Authors: Dimitra Sygkridou, Andreas Rapsomanikis, Elias Stathatos, Polycarpos Falaras, Evangelos Vitoratos

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At the present work highly transparent strip type quasi-solid state dye-sensitized solar cells (DSSCs) were fabricated through inkjet printing using nanocomposite TiO2 inks as raw materials and tested under outdoor illumination conditions. The cells, which can be considered as the structural units of large area modules, were fully characterized electrically and electrochemically and after the evaluation of the received results a large area DSSC module was manufactured. The module design was a sandwich Z-interconnection where the working electrode is deposited on one conductive glass and the counter electrode on a second glass. Silver current collective fingers were printed on the conductive glasses to make the internal electrical connections and the adjacent cells were connected in series and finally insulated using a UV curing resin to protect them from the corrosive (I-/I3-) redox couple of the electrolyte. Finally, outdoor tests were carried out to the fabricated dye-sensitized solar module and its performance data were collected and assessed.

Keywords: dye-sensitized solar devices, inkjet printing, quasi-solid state electrolyte, transparency, up-scaling

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Authors: Aroonsri Priprem, Sucharat Limsitthichaikoon, Suttasinee Thappasarapong

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Anthocyanins are natural pigments with effective UV protection but their topical use could be limited due to their physicochemical characteristics. An attempt to overcome such limitations by complexation of 2 major anthocyanin-rich sources, C. ternatea, and Z. mays, for investigation on potential use as topical anti-inflammatory. Cell studies indicate no cytotoxicity of the anthocyanin complex (AC) up to 1 mg/ml tested in HaCaT and human forehead fibroblasts by MTT. Croton oil-induced ear edema in Wistar rats suggests an effective dose of 5 mg/cm2 of AC as a topical anti-inflammatory in comparison to 0.5 mg/cm2 of fluocinolone acetonide. Niosomal encapsulation of the AC significantly prolonged the anti-inflammatory activity particularly at 8 h after topical application (p = 0.0001). The AC was not cytotoxic and its anti-inflammatory and activity was dose-dependent and prolonged by niosomal encapsulation. It has also shown to promote collagen type 1 production in cell culture. Thus, AC could be a potential candidate for topical anti-inflammatory agent from natural resources.

Keywords: anthocyanin complex, ear edema, inflammation, niosomes, skin

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Authors: Jesus Ruano, Asensi Oliva

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The hydrodynamic field generated by a jet expansion is computed via three dimensional compressible Large Eddy Simulation (LES). Finite Volume Method (FVM) will be the discretization used during this simulation as well as hybrid schemes based on Kinetic Energy Preserving (KEP) schemes and up-winding Godunov based schemes with instabilities detectors. Velocity and pressure fields will be stored at different surfaces near the jet, but far enough to enclose all the fluctuations, in order to use them as input for the acoustic solver. The acoustic field is obtained in the far-field region at several locations by means of a hybrid method based on Ffowcs-Williams and Hawkings (FWH) equation. This equation will be formulated in the spectral domain, via Fourier Transform of the acoustic sources, which are modeled from the results of the initial simulation. The obtained results will allow the study of the broadband noise generated as well as sound directivities.

Keywords: far-field noise, Ffowcs-Williams and Hawkings, finite volume method, large eddy simulation, jet noise

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Authors: Vishant Gahlaut, A Mercy Latha, Sanjay Kumar Ghosh

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Multi-stage depressed collectors (MDC) are used as an efficiency enhancement technique in traveling wave tubes the high-energy electron beam, after its interaction with the RF signal, gets velocity sorted and collected at various depressed electrodes of the MDC. The ultimate goal is to identify an optimum thermal management scheme (cooling mechanism) that could extract the heat efficiently from the electrodes. Careful thermal analysis, incorporating the cooling mechanism is required to ensure that the maximum temperature does not exceed the safe limits. A simple analytical model for quick prediction of the thermal has been developed. The model has been developed for the worst-case un-modulated DC condition, where all the thermal power is dissipated in the last electrode (typically, fourth electrode in the case of the four-stage depressed collector). It considers the thermal contact resistances at various braze joints accounting for the practical non-uniformities. Analytical results obtained from the model have been validated with simulated and experimental results.

Keywords: multi-stage depressed collector, TWTs, thermal contact resistance, thermal management

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Authors: Akram Sadouki

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Urbanization is one of the most significant drivers of biodiversity loss and ecosystem degradation. This study aims to evaluate the impact of urban expansion on local biodiversity and ecosystem functioning in Algiers, Algeria. Using a combination of field surveys, remote sensing data, and GIS analysis, we quantified changes in land use and land cover over the past three decades. Our results indicate a substantial reduction in green spaces and natural habitats, leading to a decline in native species diversity and abundance. Furthermore, we observed alterations in ecosystem services, including reduced air and water quality, increased urban heat island effects, and diminished carbon sequestration capabilities. This paper highlights the urgent need for sustainable urban planning and conservation strategies to mitigate the adverse effects of urbanization on biodiversity. We propose several policy recommendations, such as the creation of urban green belts, restoration of degraded areas, and incorporation of biodiversity considerations into city planning processes. By adopting these measures, Algiers can enhance its resilience to environmental changes and ensure the well-being of its inhabitants.

Keywords: biodiversity, ecosystem functioning, Algiers, urbanization

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Authors: Valeria Piccioni, Matthias Leschok, Ina Cheibas, Illias Hischier, Benjamin Dillenburger, Arno Schlueter, Matthias Kohler, Fabio Gramazio

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The decarbonisation of the building sector requires the development of building components that provide energy efficiency while producing minimal environmental impact. Recent advancements in large-scale 3D printing have shown that it is possible to fabricate components with embedded performances that can be tuned for their specific application. We investigate the potential of polymer 3D printing for the fabrication of translucent facade components. In this study, we explore the effect of geometry on thermal insulation of printed cavity structures following a Hot Box test method. The experimental results are used to calibrate a finite-element simulation model which can support the informed design of 3D printed insulation structures. We show that it is possible to fabricate components providing thermal insulation ranging from 1.7 to 0.95 W/m2K only by changing the internal cavity distribution and size. Moreover, we identify design guidelines that can be used to fabricate components for different climatic conditions and thermal insulation requirements. The research conducted provides the first insights into the thermal behaviour of polymer 3DP facades on a large scale. These can be used as design guidelines for further research toward performant and low-embodied energy 3D printed facade components.

Keywords: 3D printing, thermal performance, polymers, facade components, hot-box method

Procedia PDF Downloads 181

Authors: Oloniyo Kemisola Eunice, Odere Oladunni Oluwafeyikemi

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Technological change and globalization have created a new global economy with Information and Communication Technology (ICT) occupying a complex position in relation to globalization. The emergence of this new global economy has serious implications on the nature and purpose of educational institutions. The paper is basically a theoretical discourse. Data for analysis were obtained from secondary sources. The paper found that significant challenges confront the integration of ICTs in education in the areas of educational policy and planning, infrastructure, language and content, capacity building and financing in Nigeria. The paper concluded that business education needs to be well equipped to anticipate and respond to opportunities created by ICTs in order to participate productively and equitably in an increasingly technology-rich and knowledge-driven world. The paper recommended, among others, that the investments in ICTs should be used to promote the development of basic skills, problem-solving and communication skills and the professional development of teachers.

Keywords: information, communication, technology, business, education

Procedia PDF Downloads 378

Authors: M. R. Phadatare, J. V. Meshram, S. H. Pawar

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Conversion of electromagnetic energy into heat by nanoparticles (NPs) has the potential to be a powerful, non-invasive technique for biomedical applications such as magnetic fluid hyperthermia, drug release, disease treatment and remote control of single cell functions, but poor conversion efficiencies have hindered practical applications so far. In this paper, an attempt has been made to increase the efficiency of magnetic, thermal induction by NPs. To increase the efficiency of magnetic, thermal induction by NPs, one can take advantage of the exchange coupling between a magnetically hard core and magnetically soft shell to tune the magnetic properties of the NP and maximize the specific absorption rate, which is the gauge of conversion efficiency. In order to examine the tunability of magnetocrystalline anisotropy and its magnetic heating power, a representative magnetically hard material (CoFe₂O₄) has been coupled to a soft material (Ni₀.₅Zn₀.₅Fe₂O₄). The synthesized NPs show specific absorption rates that are of an order of magnitude larger than the conventional one.

Keywords: magnetic nanoparticles, surface functionalization of magnetic nanoparticles, magnetic fluid hyperthermia, specific absorption rate

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Authors: Tzu-Ping Lin, Shing-Ru Yang

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Climate change has a significant impact on human living environment, while the traditional settlement may suffer extreme thermal stress due to its specific building type and living behavior. This study selected Lutaoyang, which is the largest settlement in mountainous areas of Tainan County, for the investigation area. The microclimate parameters, such as air temperature, relative humidity, wind speed, and mean radiant temperature. The micro climate parameters were also simulated by the ENVI-met model. The results showed the banyan tree area providing good thermal comfort condition due to the shading. On the contrary, the courtyard (traditionally for the crops drying) surrounded by low rise building and consisted of artificial pavement contributing heat stress especially in summer noon. In the climate change simulations, the courtyard will become very hot and are not suitable for residents activities. These analytical results will shed light on the sustainability related to thermal environment in traditional settlements and develop adaptive measure towards sustainable development under the climate change challenges.

Keywords: thermal environment, traditional settlement, ENVI-met, Taiwan

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Authors: Kunle Oparinde, Rachel Matteau-Matsha, Felix Awung

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In recent times, the issue of gender-based violence against women in South Africa is prevalent in headlines due to the high rate of attacks directed towards women. Ranging from teenagers to adults, women are continuously targeted indiscriminately in what is seemingly becoming a prolonged cycle in the country. To this end, human rights activists, organisations, and political leaders have managed to somewhat verbally condemn the atrocious acts. Further, interested people in South Africa, through walks and protests, have continued to speak against the swinging violence against women in the country. The thrust in this study is to explore and analyse how discourse (language) has been employed as a resounding voice against gender violence in the country. Through a purposive sampling of materials employed during walks and protests, collected from online sources, we examine how language is being used to combat and confront the issue of gender violence viz-a-viz how it continues to serve as a crucial tool in repelling gender violence.

Keywords: gender, violence, language, discourse, resistance

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Authors: Maszlee Malik

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If the contemporary notion of welfare arises from the horizontal material needs and to be structured by the vertical framework of the state, Islamic societal-based welfare is to be shaped by moral based and faith inspired ihsan (benevolence) culture in producing the ‘Ihsani’ version of the enhancement of the political participation, democratic culture, good governance and self-realisation, which eventually culminating towards the bigger picture of ‘development’. This paper will analytically investigate on how the over-arching principle of ‘ihsan’ could be an essential tool in harmonizing the social-based welfare instrument as another conceptual framework to formulate a conceptual approach towards development and poverty elevation beyond the state. Essentially, this research will employ the inductive method of exploration on Islamic epistemological sources and historical evidence, to formulate the discursive concept of non-state societal-based welfare based on the ‘ihsani’ framework.

Keywords: benevolent society, development, Hisbah, HomoIslamicus, Ihsani, islamic epistemology, state, social capital, societal-based welfare, zakat

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Authors: Fakieh Alrabai

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This study investigated the effects on learner anxiety of anxiety-reducing strategies utilized by English as foreign language teachers in Saudi Arabia. The study was conducted in two stages. In the first stage, sources of foreign language anxiety for Saudi learners of English (N = 596) were identified using The Foreign Language Classroom Anxiety Scale (FLCAS). In the second stage, 465 learners who were divided almost equally into two groups (experimental vs. control) and 12 teachers were recruited. Anxiety-reducing strategies were implemented exclusively in the treatment group for approximately eight weeks. FLCAS was used to assess learners’ FL anxiety levels before and after treatment. Statistical analyses (e.g. ANOVA and ANCOVA) were used to evaluate the study findings. These findings revealed that the intervention led to significantly decreased levels of FL anxiety for learners in the experimental group compared with increased levels of anxiety for those in the control group.

Keywords: communication apprehension, EFL teaching/learning, fear of negative evaluation, foreign language anxiety

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Authors: Özgür Emi̇nağaoğlu, Hayal Akyildirim Beğen, Şevval Sali̇oğlu, Emrah Yüksel

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This study was carried out in order to determine the scientific name, common name, local names, location, botanical characteristics, used parts, intended use, local usage patterns, usage in the literature of plant species used for medicinal and aromatic purposes in Ardanuç (Artvin, Türkiye) between 2020-2023 years. The research area is located in the A9 square according to Davis’s grid system and is phytogeographically located in the colchic subsection of the Euxine part of the Euro-Siberian flora area of the Holarctic region. As a result of the studies, it has been determined that 167 plant species belonging to 79 families are used for medicinal and aromatic purposes. The families that contain the most taxa in the research area are, respectively, Rosaceae (19 taxa), Asterecaeae (15 taxa), and Lamiaceae (14 taxa). It has been determined that the medicinal, aromatic plants of the Ardanuç region are mostly used in the treatment of diseases (59%), and the plants are mostly used in the treatment of diabetes (37%). It was determined that the most applied method in the internal use of plants was decoction (48%). As a result of the research, the most commonly used plants in different diseases are Sambucus nigra, Plantago lanceolata, Satureja hortensis, Hypericum perforatum, Juniperus communis. These plants are used in the treatment of many diseases, such as colds, cancer, anemia and diabetes.

Keywords: Ardanuç, Artvin, Medicinal and Aromatic plant, Türkiye

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Authors: Ali Akbar

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The main purpose of this essay is to examine whether or not the earthly punishments in regards to apostates that are often found in classical Islamic sources are applicable in the present context. The paper indeed addresses how Muslims should understand the question of apostasy in the contemporary context. To do so, the paper first argues that an accurate understanding of the way the Quranic verses and prophetic hadiths deal with the concept of apostasy could help us rethink and re-examine the classical Islamic laws on apostasy in the present context. In addition, building on Abdolkarim Soroush’s theory of contraction and expansion of religious knowledge, this article argues that approaches to apostasy in the present context can move away from what prescribed by classical Islamic laws. Finally, it argues that instances of persecution of apostates in the early days of Islam during the Medinan period of Muhammad’s prophetic mission should be interpreted in their own socio-historical context. Rereading these reports within our modern context supports the mutability of the traditional corporal punishments of apostasy.

Keywords: apostasy, Islam, Quran, hadith, Abdolkarim Soroush, contextualization

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Authors: O. M. Omar, A. M. Heniegal, G. D. Abd Elhameed, H. A. Mohamadien

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Local steel slag is produced as a by-product during the oxidation of steel pellets in an electric arc furnace. Using local steel slag waste as a hundred substitute of crushed stone in construction materials would resolve the environmental problems caused by the large-scale depletion of the natural sources of dolomite. This paper reports the experimental study to investigate the influence of a hundred replacement of dolomite as a coarse aggregate with local steel slag, on the fresh and hardened geopolymer concrete properties. The investigation includes traditional testing of hardening concrete, for selected mixes of cement and geopolymer concrete. It was found that local steel slag as a coarse aggregate enhanced the slump test of the fresh state of cement and geopolymer concretes. Nevertheless the unit weight of concretes was affected. Meanwhile, the good performance was observed when fly ash used as geopolymer concrete based.

Keywords: geopolymer, molarity, steel slag, sodium hydroxide, sodium silicate

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Authors: Zhuo Cheng, Gaohang Cui, Yang Zheng, Zhiqiang-Pan

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To explore the effect of freeze-thaw cycles on saline soil mechanical properties of fly ash, this study examined the influence of different numbers of freezing and thawing cycles, fly ash content, and moisture content of saline soil in unconfined compression tests and triaxial shear tests. With increased fly ash content, the internal friction angle, cohesion, unconfined compressive strength, and shear strength of the improved soil increased at first and then decreased. Using the Desk-Expert 8.0 software and based on significance analysis theory, the number of freeze-thaw cycles, fly ash content, water content, and the interactions between various factors on the mechanical properties of saline soil were studied. The results showed that the number of freeze-thaw cycles had a significant effect on the mechanical properties of saline soil, while the fly ash content had a weakly significant effect. At the same time, interaction between the number of freeze-thaw cycles and the water content had a significant effect on the unconfined compressive strength and the cohesion of saline soil, and the interaction between fly ash content and the number of freeze-thaw cycles only had a significant effect on the unconfined compressive strength.

Keywords: fly ash, saline soil, seasonally frozen area, significance analysis, qualitative analysis

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Authors: Said Lamghari, Abdelkader Outzourhit, Hassan Hamdi, Mohamed Krarouch, Fatima Ait Nouh, Mickael Benhaim, Mehdi Khaldoun

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Traditional Hammams are big consumers of water and wood-energy. Any approach to reduce this consumption will contribute to the preservation of these two resources that are more and more stressed in Morocco. In the InnoTherm/InnoBiomass 2014 project HYBRIDBATH, funded by the Research Institute for Solar Energy and New Energy (IRESEN), we will use a hybrid system consisting of a micro-CSP system and a biomass boiler for water and space heating of a Hammam. This will overcome the problem of intermittency of solar energy, and will ensure continuous supply of hot water and heat. We propose to use local agricultural residues (olive pomace, shells of walnuts, almonds, Argan ...). Underfloor heating using either copper or PEX tubing will perform the space heating. This work focuses on the description of the system and the activities carried out so far: The installation of the system, the principle operation of the system and some preliminary test results.

Keywords: biomass boiler, hot water, hybrid systems, micro-CSP, parabolic sensor, solar energy, solar fraction, traditional hammam, underfloor heating

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Authors: Maha Mourad, Rania Samir

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This paper seeks to explain the adoption of technological innovations in a business to consumer context. Specifically, the use of web based technology (WEBCT/blackboard) in the delivery of educational material and communication with students at universities in Egypt is the focus of this study. The analysis draws on existing research in a B2C context which highlights the importance of internal organization characteristics, perceived attributes of the innovation as well as consumer based factors as the main drivers of adoption. A distinctive B2C model is developed drawing on Roger’s innovation adoption model, as well as theoretical and empirical foundations in previous innovation adoption literature to study the adoption of technological innovations in higher education in Egypt. The model proposes that the adoption decision is dependent on a combination of perceived attributes of the innovation, inter-organization factors and consumer factors. The model is testified drawing on the results of empirical work in the form of a large survey conducted on students in three different universities in Egypt (one public, one private and one international). In addition to the attributes of the innovation, specific organization factors (such as university resources) as well as consumer factors were identified as likely to have an important influence on the adoption of technological innovations in higher education.

Keywords: innovation, WEBCT, higher education, adoption, Egypt

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Authors: Ife Elegbeleye, Nnditshedzeni Eric, Regina Maphanga, Femi Elegbeleye, Femi Agunbiade

Abstract:

The global potential of other renewable energy sources such as wind, hydroelectric, bio-mass, and geothermal is estimated to be approximately 13 %, with hydroelectricity constituting a larger percentage. Sunlight provides by far the largest of all carbon-neutral energy sources. More energy from the sunlight strikes the Earth in one hour (4.3 × 1020 J) than all the energy consumed on the planet in a year (4.1 × 1020 J), hence, solar energy remains the most abundant clean, renewable energy resources for mankind. Photovoltaic (PV) devices such as silicon solar cells, dye sensitized solar cells are utilized for harnessing solar energy. Polyene-diphenylaniline organic molecules are important sets of molecules that has stirred many research interest as photosensitizers in TiO₂ semiconductor-based dye sensitized solar cells (DSSCs). The advantages of organic dye molecule over metal-based complexes are higher extinction coefficient, moderate cost, good environmental compatibility, and electrochemical properties. The polyene-diphenylaniline organic dyes with basic configuration of donor-π-acceptor are affordable, easy to synthesize and possess chemical structures that can easily be modified to optimize their photocatalytic and spectral properties. The enormous interest in polyene-diphenylaniline dyes as photosensitizers is due to their fascinating spectral properties which include visible light to near infra-red-light absorption. In this work, density functional theory approach via GPAW software, Avogadro and ASE were employed to study the effect of methoxy functionalized group on the spectral properties of polyene-diphenylaniline dyes and their photons absorbing characteristics in the visible region to near infrared region of the solar spectrum. Our results showed that the two-phenyl based complexes D5 and D7 exhibits maximum absorption peaks at 750 nm and 850 nm, while D9 and D11 with methoxy group shows maximum absorption peak at 800 nm and 900 nm respectively. The highest absorption wavelength is notable for D9 and D11 containing additional polyene and methoxy groups. Also, D9 and D11 chromophores with the methoxy group shows lower energy gap of 0.98 and 0.85 respectively than the corresponding D5 and D7 dyes complexes with energy gap of 1.32 and 1.08. The analysis of their electron injection kinetics ∆Ginject into the band gap of TiO₂ shows that D9 and D11 with the methoxy group has higher electron injection kinetics of -2.070 and -2.030 than the corresponding polyene-diphenylaniline complexes without the addition of polyene group with ∆Ginject values of -2.820 and -2.130 respectively. Our findings suggest that the addition of functionalized group as an extension of the organic complexes results in higher light harvesting efficiencies and bathochromic shift of the absorption spectra to higher wavelength which suggest higher current densities and open circuit voltage in DSSCs. The study suggests that the photocatalytic properties of organic chromophores/complexes with donor-π-acceptor configuration can be enhanced by the addition of functionalized groups.

Keywords: renewable energy resource, solar energy, dye sensitized solar cells, polyene-diphenylaniline organic chromophores

Procedia PDF Downloads 111

Authors: Erika Mattio , Edoardo Casolo

Abstract:

This project studies in a complete and innovative way the lesser known southern roman border: the limes africanus. In this work, thanks to the comparison of archaeological, historical and epigraphic sources, the evolution and changes that occurred in the cities and areas around the limes were analysed. As of now, there are many studies relative to the roman imperial period, however there are not that many analysing the evolution of the limes from the Islamic conquest to the modern day, comparing the ancient, byzantine, islamic and contemporary periods, understanding the significance of the limes, it s role and the cities and commerce that were defined by it in north Africa. Using modern methods of remote sensing and landscape archaeology, a georeferencing of the area documented in the thirties of the last century by French military aviation colonel Jean Baradez was created, showing that the limes africanus had survived the fall of the roman empire and continued to be important also for the Islamic dynasties that came later, even until the italo-turkish war and the Italian conquest of Libya. With this research we wish to demonstrate the continuation through time of the limes africanus and whether today it exists still or not.

Keywords: Limes Tripolitanus, Muslim, North Africa, Romans

Procedia PDF Downloads 202

Authors: Chetan Mahawar, Sarath Chandran, Sridhar Panigrahi, V. P. Shaji

Abstract:

The ever-growing advancement in space exploration has led to an alarming concern for space debris removal as it restricts further launch operations and adventurous space missions; hence numerous studies have come up with technologies for re-entry predictions and material selection processes for mitigating space debris. The selection of material and operating conditions is determined with the objective of lightweight structure and ability to demise faster subject to spacecraft survivability during its mission. Since the demisability of spacecraft depends on evolving thermal material properties such as emissivity, specific heat capacity, thermal conductivity, radiation intensity, etc. Therefore, this paper presents the analysis of evolving thermal material properties of spacecraft, which affect the demisability process and thus estimate demise time using the demisability model by incorporating evolving thermal properties for sensible heating followed by the complete or partial break-up of spacecraft. The demisability analysis thus concludes the best suitable spacecraft material is based on the least estimated demise time, which fulfills the criteria of design-for-survivability and as well as of design-for-demisability.

Keywords: demisability, emissivity, lightweight, re-entry, survivability

Procedia PDF Downloads 116