Search results for: NPO dielectric material

Authors: Z. H. Safari, M. Anbia, G. H. Kouzegari, R. Amirkhani

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Toluene and Nitro derivatives are widely used in industry particularly in various defense applications. Tri-nitro-toluene derivative is a powerful basic explosive material that is a basis upon which to compare equivalent explosive power of similar materials. The aim of this paper is to measure the explosive power of these hazardous substances in fuels having different shelf-life and therefore optimizing their storage and maintenance. The methodology involves measuring the amounts of di- nitro- toluene and tri-nitro-toluene in the aged samples at 90 ° C by gas chromatography. Results show no significant difference in the concentration of the TNT compound over a given time while there was a significant difference in DNT compound over the same period. The underlying reason is attributed to the simultaneous production of the material with destruction of stabilizer.

Keywords: dinitrotoluene, trinitrotoluene, double-base solid propellants, artificial aging

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Authors: Bensacia Nabila, Hadj-Ziane Amel, Sefah Karima

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Carbon nanocomposites have received more attention in the last years in view of their special properties such as low density, high specific surface area, and thermal and mechanical stability. Taking into account the importance of these materials, many studies aimed at improving the synthesis process have been conducted. However, the presence of impurities could affect significantly the properties of these materials, and the characterization of these compounds is an important challenge to assure the quality of the new carbon nanocomposites. The present study aims to develop a new recyclable decontaminating material for dyes removal. This new material consists of an active element based on carbon nanotubes wrapped in a microcapsule of iron oxide. The adsorbent is characterized by Transmission electron microscopy, X-ray diffraction and the surface area was measured by the BET method.

Keywords: carbon nanocomposite, chitozen, elimination, dyes

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Authors: Najah Majouri, Mohamed El Mankibi, Jalila Sghaier

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This study examined the geotechnical, mineralogical, thermal and physical characterization of clays in south-west Tunisia. Its aims are to elaborate an insulator material based on the clay used in the field of building materials. The geotechnical study showed that the clay studied is characterized by a high degree of plasticity of 30.83%. High mineralogical findings showed that the sample consisted mainly of kaonolite and other clay minerals. The thermal and physical properties of the different samples are obtained by mixing clays, which indicates a promising future for the use of this type of clays in the production of insulating building materials.

Keywords: clay, energy-saving, insulator material, and South-West Tunisia.

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Authors: Manal Bouasria, Mohammed-Hichem Benzaama, Valérie Pralong, Yassine El Mendili

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Reducing the quantity of cement in cementitious composites can help to reduce the environmental effect of construction materials. By-products such as ferronickel slags (FNS), fly ash (FA), and Crepidula fornicata (CR) are promising options for cement replacement. In this work, we investigated the relevance of substituting cement with FNS-CR and FA-CR on the mechanical properties of mortar and on the thermal properties of concrete. Foraging intervals ranging from 2 to 28 days, the mechanical properties are obtained by 3-point bending and compression tests. The chosen mix is used to construct a prototype in order to study the material’s hygrothermal performance. The data collected by the sensors placed on the prototype was utilized to build an artificial neural network.

Keywords: artificial neural network, cement, circular economy, concrete, by products

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Authors: Hubert Feiglstorfer

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Due to its location in a transition zone from the Pannonian to the pre-Alpine region, the east of Austria shows a small-scale diversity in the regional development of certain vernacular building techniques. In this article the relationship between natural building material resources, topography and climate will be examined. Besides environmental preconditions, social and economic historical factors have developed different construction techniques within certain regions in the Weinviertel and Burgenland, the two eastern federal states of Austria. But even within these regions, varying building techniques were found, due to the locally different use of raw materials like wood, stone, clay, lime, or organic fibres. Within these small-scale regions, building traditions were adapted over the course of time due to changes in the use of the building material, for example from wood to brick or from wood to earth. The processing of the raw materials varies from region to region, for example as rammed earth, cob, log, or brick construction. Environmental preconditions cross national borders. For that reason, developments in the neighbouring countries, the Czech Republic, Slovakia, Hungary and Slovenia are included in this analysis. As an outcome of this research a map was drawn which shows the interrelation between locally available building materials, topography, climate and local building techniques? As a result of this study, which covers the last 300 years, one can see how the local population used natural resources very sensitively adapted to local environmental preconditions. In the case of clay, for example, changes of proportions of lime and particular minerals cause structural changes that differ from region to region. Based on material analyses in the field of clay mineralogy, on ethnographic research, literature and archive research, explanations for certain local structural developments will be given for the first time over the region of East Austria.

Keywords: European crafts, material culture, architectural history, earthen architecture, earth building history

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Authors: Wu Peiqin

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Flexible thermoelectric devices are light and flexible, which can be in close contact with any shape of heat source surfaces to minimize heat loss and achieve efficient energy conversion. Among the wide application fields, energy harvesting via flexible thermoelectric generators can adapt to a variety of curved heat sources (such as human body, circular tubes, and surfaces of different shapes) and can drive low-power electronic devices, exhibiting one of the most promising technologies in self-powered systems. The heat flux along the cross-section of the flexible thin-film generator is limited by the thickness, so the temperature difference decreases during the generation process, and the output power is low. At present, most of the heat flow directions of the thin film thermoelectric generator are along the thin-film plane; however, this method is not suitable for attaching to the human body surface to generate electricity. In order to make the film generator more suitable for thermoelectric generation, it is necessary to apply a flexible heatsink on the air sides with the film to maintain the temperature difference. In this paper, Bismuth telluride thermoelectric paste was deposited on polyimide flexible substrate by a screen printing method, and the flexible thermoelectric film was formed after drying. There are ten pairs of thermoelectric legs. The size of the thermoelectric leg is 20 x 2 x 0.1 mm, and adjacent thermoelectric legs are spaced 2 mm apart. A phase change material-based flexible heatsink was designed and fabricated. The flexible heatsink consists of n-octadecane, polystyrene, and expanded graphite. N-octadecane was used as the thermal storage material, polystyrene as the supporting material, and expanded graphite as the thermally conductive additive. The thickness of the flexible phase change material-based heatsink is 2mm. A thermoelectric performance testing platform was built, and its output performance was tested. The results show that the system can generate an open-circuit output voltage of 3.89 mV at a temperature difference of 10K, which is higher than the generator without a heatsink. Therefore, the flexible heatsink can increase the temperature difference between the two ends of the film and improve the output performance of the flexible film generator. This result promotes the application of the film thermoelectric generator in collecting human heat for power generation.

Keywords: flexible thermoelectric generator, screen printing, PCM, flexible heatsink

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Authors: Pedram Khazaie, Sajjad Moein

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In the conventional hot forging of Tongue, which is a fitting for polymer insulator, the material wasted to flash accounts for 20-30% of workpiece. In order to reduce the cost of forged products, this waste material must be minimized. In this study, a flashless forging die is designed and simulated using the finite element method (FEM). A solution to avoid overloading the die with a simple preform is also presented. Moreover, since in flashless forging, burr is formed on the edge of workpiece, a controlled flash forging method is proposed to solve this problem. The simulation results have been validated by experiments; achieving close agreement between simulated and experimental data. It was shown that numerical modeling is helpful in reducing cost and time in the manufacturing process.

Keywords: burr formation, die design, finite element method, flashless forging

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Authors: Nixon Kuruvila, H. V. Ravindra

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Wire-cut Electro Discharge Machining (WEDM) is a special form of conventional EDM process in which electrode is a continuously moving conductive wire. The present study aims at determining parametric influence and optimum process parameters of Wire-EDM using Taguchi’s Technique and Genetic algorithm. The variation of the performance parameters with machining parameters was mathematically modeled by Regression analysis method. The objective functions are Dimensional Accuracy (DA) and Material Removal Rate (MRR). Experiments were designed as per Taguchi’s L16 Orthogonal Array (OA) where in Pulse-on duration, Pulse-off duration, Current, Bed-speed and Flushing rate have been considered as the important input parameters. The matrix experiments were conducted for the material Oil Hardened Non Shrinking Steel (OHNS) having the thickness of 40 mm. The results of the study reveals that among the machining parameters it is preferable to go in for lower pulse-off duration for achieving over all good performance. Regarding MRR, OHNS is to be eroded with medium pulse-off duration and higher flush rate. Finally, the validation exercise performed with the optimum levels of the process parameters. The results confirm the efficiency of the approach employed for optimization of process parameters in this study.

Keywords: dimensional accuracy (DA), regression analysis (RA), Taguchi method (TM), volumetric material removal rate (VMRR)

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Authors: Jalal M. Abdallah

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This paper presents experimental studies carried out on a three phase transformer to investigate and develop the transformer models, which help in testing procedures, describing and evaluating the transformer dielectric conditions process and methods such as: the partial discharge (PD) localization in windings. The measurements are based on the transfer function methods in transformer windings by frequency response analysis (FRA). Numbers of tests conditions were applied to obtain the sensitivity frequency responses of a transformer for different type of faults simulated in a particular phase. The frequency responses were analyzed for the sensitivity of different test conditions to detect and identify the starting of small faults, which are sources of PD. In more detail, the aim is to explain applicability and sensitivity of advanced PD measurements for small short circuits and its localization. The experimental results presented in the paper will help in understanding the sensitivity of FRA measurements in detecting various types of internal winding short circuits in the transformer.

Keywords: frequency response analysis (FRA), measurements, transfer function, transformer

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Authors: M. Rashid Hussain, Shady S. Refaat

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The high voltage power transformer is the most essential part of the electrical power utilities. Reliability on the transformers is the utmost concern, and any failure of the transformers can lead to catastrophic losses in electric power utility. The causes of transformer failure include insulation failure by partial discharge, core and tank failure, cooling unit failure, current transformer failure, etc. For the study of power transformer defects, finite element analysis (FEA) can provide valuable information on the severity of defects. FEA provides a more accurate representation of complex geometries because they consider thermal, electrical, and environmental influences on the insulation models to obtain basic characteristics of the insulation system during normal and partial discharge conditions. The purpose of this paper is the time domain analysis of defects 3D model of high voltage power transformer using FEA to study the electric field distribution at different points on the defects.

Keywords: power transformer, finite element analysis, dielectric response, partial discharge, insulation

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Authors: Ina Dajci

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Biologic Materials presents groundbreaking transdisciplinary research aimed at fostering new collaborative models across the Built Environment, Forestry, and Agriculture sectors. This initiative seeks to establish innovative paradigms for local and global material flows by developing a biocompatible, regenerative material economy. The project focuses on creating materials derived from biowaste and silvicultural practices, ensuring the preservation of endangered indigenous and vernacular techniques through the integration of emerging biosciences. By utilizing biomaterials sourced from agricultural waste and forest byproducts, the initiative incorporates fabrication methods recognized by UNESCO as ‘intangible cultural heritage of humanity,’ which are currently at risk. The structural, mechanical, and environmental properties of these materials are enhanced through advanced CAD-CAM fabrication, along with energy-efficient biochemical and bacterial processes that promote healthy indigo coloration. Furthermore, the integration of AI technologies in species selection facilitates a novel partnership model, enabling designers to collaborate effectively with forest managers and silviculture practitioners. This collaborative approach not only optimizes the use of plant-based materials but also enhances biodiversity and climate resilience in regional ecosystems. Overall, this project embodies a holistic strategy for addressing environmental challenges while revitalizing traditional practices and fostering sustainable innovation.

Keywords: material, architecture, culture, heritage, ecology, environment

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Authors: Meriem Harmel, Houari Khachai

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We have investigated the structural, electronic and optical properties of a compound perovskite CsSrF3 using the full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, both the local density approximation (LDA) and the generalized gradient approximation (GGA) were used for exchange-correlation potential calculation. The ground state properties such as lattice parameter, bulk modulus and its pressure derivative were calculated and the results are compared whit experimental and theoretical data. Electronic and bonding properties are discussed from the calculations of band structure, density of states and electron charge density, where the fundamental energy gap is direct under ambient conditions. The contribution of the different bands was analyzed from the total and partial density of states curves. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 35.0 eV. This is the first quantitative theoretical prediction of the optical properties for the investigated compound and still awaits experimental confirmations.

Keywords: DFT, fluoroperovskite, electronic structure, optical properties

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Authors: O. F. Elkommos

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Teaching English as a Second Language (TESL) has become a very rich area of research. Practitioners or teachers of English as a foreign or a second language are now promoting both collaborative learning and collaborative teaching. Students learning a language collaboratively and cooperatively are learning in a better environment of team work where they learn from each other. Further, teaching English collaboratively also creates an enriching environment that is also very enriching to students’ and teachers’ experiences of learning and teaching. Moreover, action research stems from actual teacher concerns and students’ needs. Reflection in turn, on the experience of the material taught and the delivery of material is becoming an integral part of the teaching and learning experience self- evaluation and self-development. In this case, the concern of the research field in the area of TESL will be the development of teaching delivery, material and quality of learning. In the present research, the TESL module taught to year two students in the Faculty of Arts and Humanities, British University in Egypt (BUE) will be evaluated reflexively by the students and teachers. The module was taught to students in two different specialisms. It was taught and delivered through collaborative teaching and was evaluated by both teachers and students as very successful and enjoyable. The reflections of both teachers and students as well as student results confirm that it was a success.

Keywords: action research, addressing differentiation, collaborative teaching, reflective teaching and learning, reflexive learning, reflexive teaching, self-development, self-evaluation, TESL

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Authors: Lucas Wilman Crispim, Patrícia Hallack, Maikel Ballester

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This work aims at modeling electric discharges in gas mixtures. The mathematical model mimics the ignition process in a commercial spark-plug when a high voltage is applied to the plug terminals. A longitudinal unidimensional Cartesian domain is chosen for the simulation region. Energy and mass transfer are considered for a macroscopic fluid representation, while energy transfer in molecular collisions and chemical reactions are contemplated at microscopic level. The macroscopic model is represented by a set of uncoupled partial differential equations. Microscopic effects are studied within a discrete model for electronic and molecular collisions in the frame of ZDPlasKin, a plasma modeling numerical tool. The BOLSIG+ solver is employed in solving the electronic Boltzmann equation. An operator splitting technique is used to separate microscopic and macroscopic models. The simulation gas is a mixture of atomic Argon neutral, excited and ionized. Spatial and temporal evolution of such species and temperature are presented and discussed.

Keywords: CFD, electronic discharge, ignition, spark plug

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Authors: Mohammed Mohsin Ali H., Mohamed Haneef

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The connecting rod transmits the piston load to the crank causing the latter to turn, thus converting the reciprocating motion of the piston into a rotary motion of the crankshaft. Connecting rods are subjected to forces generated by mass and fuel combustion. This study investigates and compares the fatigue behavior of forged steel, powder forged and ASTM a 514 steel cold quenched connecting rods. The objective is to suggest for a new material with reduced weight and cost with the increased fatigue life. This has entailed performing a detailed load analysis. Therefore, this study has dealt with two subjects: first, dynamic load and stress analysis of the connecting rod, and second, optimization for material, weight and cost. In the first part of the study, the loads acting on the connecting rod as a function of time were obtained. Based on the observations of the dynamic FEA, static FEA, and the load analysis results, the load for the optimization study was selected. It is the conclusion of this study that the connecting rod can be designed and optimized under a load range comprising tensile load and compressive load. Tensile load corresponds to 360^o crank angle at the maximum engine speed. The compressive load is corresponding to the peak gas pressure. Furthermore, the existing connecting rod can be replaced with a new connecting rod made of ASTM a 514 steel cold quenched that is 12% lighter and 28% cheaper.

Keywords: connecting rod, ASTM a514 cold quenched material, static analysis, fatigue analysis, stress life approach

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Authors: Edison A. Bonifaz

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In this work, a numerical procedure is proposed to design dense multi-material structures using the Directed Energy Deposition (DED) process. A thermo-mechanical finite element model to predict thermal cycles and residual stresses is presented. A numerical layer build-up procedure coupled with a moving heat flux was constructed to minimize strains and residual stresses that result in the multi-layer deposition of an AISI 316 austenitic steel on an AISI 304 austenitic steel substrate. To simulate the DED process, the automated interface of the ABAQUS AM module was used to define element activation and heat input event data as a function of time and position. Of this manner, the construction of ABAQUS user-defined subroutines was not necessary. Thermal cycles and thermally induced stresses created during the multi-layer deposition metal AM pool crystallization were predicted and validated. Results were analyzed in three independent metal layers of three different experiments. The one-way heat and material deposition toolpath used in the analysis was created with a MatLab path script. An optimal combination of feedstock and heat input printing parameters suitable for fabricating multi-material dense structures in the directed energy deposition metal AM process was established. At constant power, it can be concluded that the lower the heat input, the lower the peak temperatures and residual stresses. It means that from a design point of view, the one-way heat and material deposition processing toolpath with the higher welding speed should be selected.

Keywords: event series, thermal cycles, residual stresses, multi-pass welding, abaqus am modeler

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Authors: Adinda Syifa Azhari, Eleonora Agustine, Dini Fitriani

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This measurement has been done to analyze the impact of industrial pollution on the environment. Our research is to indicate the soil which has contained some pollution by industrial activity around the area, especially in Sumedang, West Java. The parameter phsyics such as total dissolved solid, volumetric water content, electrical conductivity bulk and FD have shown that the soil has polluted and measured by Decagon EM 50. Decagon EM 50 is one of the geophysical environment instrumentation that is used to interpret the soil condition. This experiment has given a result of these parameter physics, these are: Volumetric water content (m³/m³) = 0,154 – 0,384; Electrical Conductivity Bulk (dS/m) = 0,29 – 1,11 ; Dielectric Permittivity (DP) = 77,636 – 78, 339.Based on these data, we have got the conclusion that the area has, in fact, been contaminated by dangerous materials. VWC is parameter physics that has shown water in soil. The data show the pollution of the soil at the place, of which the specifications are PH, Total Dissolved Solid (TDS), Electrical Conductivity (EC) bigger (>>) and Frequency Dependent (FD) smaller (<<); that means the soil is alkali with big grain and has high salt concentration.

Keywords: Decagon EM 50, electrical conductivity, industrial textiles, land, pollution

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Authors: Mnasri Faiza, El Ganaoui Mohammed, Khelifa Mourad, Gabsi Slimane

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The main objective of this paper is to describe the hydrothermal behavior through porous material of construction due to temperature gradient. The construction proposed a bi-layer structure which composed of two different materials. The first is a bio-sourced panel named IBS-AKU (inertia system building), the second is the Neopor material. This system (IBS-AKU Neopor) is developed by a Belgium company (Isohabitat). The study suggests a multi-layer structure of the IBS-AKU panel in one dimension. A numerical method was proposed afterwards, by using the finite element method and a refined mesh area to strong gradients. The evolution of temperature fields and the moisture content has been processed.

Keywords: heat transfer, moisture diffusion, porous media, composite IBS-AKU, simulation

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Authors: Alejandra Betancur Sánchez, Carmen Elena Zapata Sánchez, Juan Bautista López Ortiz

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Adverse effects and increased air pollution has raised concerns about regulatory policies and has fostered the development of new air quality standards; this is due to the complexity of the composition and the poorly understood reactions in the atmospheric environment. Toxic compounds act as environmental agents having various effects, from irritation to death of cells and tissues. A toxic agent is defined an adverse response in a biological system. There is a particular class that produces some kind of alteration in the genetic material or associated components, so they are recognized as genotoxic agents. Within cells, they interact directly or indirectly with DNA, causing mutations or interfere with some enzymatic repair processes or in the genesis or polymerization of proteinaceous material involved in chromosome segregation. An air pollutant may cause or contribute to increased mortality or serious illness and even pose a potential danger to human health. The aim of this study was to evaluate the effect on the viability and the genotoxic potential on the cell lines CHO-K1 and Jurkat and peripheral blood of particulate matter PM T lymphocytes 2.5 obtained from filters collected three monitoring stations network air quality Aburrá Valley. Tests, reduction of MTT, trypan blue, NRU, comet assay, sister chromatid exchange (SCE) and chromosomal aberrations allowed evidence reduction in cell viability in cell lines CHO-K1 and Jurkat and damage to the DNA from cell line CHOK1, however, no significant effects were observed in the number of SCEs and chromosomal aberrations. The results suggest that PM2.5 material has genotoxic potential and can induce cancer development, as has been suggested in other studies.

Keywords: PM2.5, cell line Jurkat, cell line CHO-K1, cytotoxicity, genotoxicity

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Authors: Ouaaz Oum Essaad, Melbouci Bachir

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The experimental study conducted has a dual purpose: to valorize the clay material in the road domain and improve the lift of the shape layers by strengthening with plastic waste (in the form of aggregates). To do this, six mixtures of Clay and sand of different percentages were studied: 100% Clay, 95% Clay + 05% Sand, 90% Clay + 10% Sand, 85% Clay + 15% Sand, 80% Clay + 20% Sand, 75% Clay + 25% Sand. Proctor compaction and simple compression tests have been carried out on mixtures (sand + clay + plastic waste). The results obtained show a clear evolution of the characteristics of the Proctor test and the compressive strength of the mixtures according to the different types and percentages of the recycled plastic Plasticity and consistency index are important parameters that play a role in the toughness of plastic soil.

Keywords: valorization, recycling, soil mixture, mechanical tests

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Authors: Z. Funda Türkmenoğlu, Mehmet Türkmenoglu, Demet Yavuz,

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In this study, the effects of waste marbles as aggregate material on workability and hardened concrete characteristics of self compacting lightweight concrete are investigated. For this purpose, self compacting light weight concrete are produced by waste marble aggregates are replaced with fine aggregate at 5%, 7.5%, and 10% ratios. Fresh concrete properties, slump flow, T₅₀ time, V funnel, compressive strength and ultrasonic pulse velocity of self compacting lightweight concrete are determined. It is concluded from the test results that using waste marbles as aggregate material by replacement with fine aggregate slightly affects fresh and hardened concrete characteristics of self compacting lightweight concretes.

Keywords: hardened concrete characteristics, self compacting lightweight concrete, waste marble, workability

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Authors: Concetta Busacca, Leone Frusteri, Orazio Di Blasi, Alessandra Di Blasi

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The large-scale extension of renewable energy led, recently, to the development of efficient and low-cost electrochemical energy storage (EES) systems such as batteries. Although lithium-ion battery (LIB) technology is relatively mature, several issues regarding safety, cyclability, and high costs must be overcome. Thanks to the availability and low cost of sodium, sodium-ion batteries (NIB) have the potential to meet the energy storage needs of the large-scale grid, becoming a valid alternative to LIB in some energy sectors, such as the stationary one. However, important challenges such as low specific energy and short cyclic life due to the large radius of Na+ must be faced to introduce this technology into the market. As an important component of SIBs, cathode materials have a significant effect on the electrochemical performance of SIBs. Recently, sodium layer transition metal oxides, phosphates, and organic compounds have been investigated as cathode materials for SIBs. In particular, phosphate-based compounds such as NaₓMPO₄ (M= Fe, Co, Mn) have been extensively studied as cathodic polyanion materials due to their long cycle stability and appropriate operating voltage. Among these, an interesting cathode material is the NaMnPO₄ based one, thanks to the stability and the high redox potential of the Mn²⁺/Mn³⁺ ion pair (3÷4 V vs. Na+/Na), which allows reaching a high energy density. This work concerns with the synthesis of a composite material based on NaMnPO₄ and carbon nanofibers (NaMnPO₄-CNF) characterized by a mixed crystalline structure between the maricite and olivine phases and a self-standing manufacture obtained by electrospinning technique. The material was tested in a Na-ion battery coin cell in half cell configuration, and showed outstanding electrocatalytic performances with a specific discharge capacity of 125 mAhg⁻¹ and 101 mAhg⁻¹ at 0.3C and 0.6C, respectively, and a retention capacity of about 80% a 0.6C after 100 cycles.

Keywords: electrospinning, self standing materials, Na ion battery, cathode materials

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Authors: Riki H. Patel, Arpan Desai, Trushit Upadhyaya, Shobhit K. Patel

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The micro strip antennas area has seen some inventive work in recent years and is now one of the most dynamic fields of antenna theory. A novel and simple printed wideband monopole antenna is presented. Printed on a single dielectric substrate and easily fed by using a 50 ohm microstip line, low-profile antenna structure with two parallel S-shaped meandered line of same size. In this research, S–form micro strip patch antenna is designed from measuring the prototypes of the proposed antenna one available bands with 10db return loss bandwidths of about GPS application (GPS L2 1490 MHz) and covering the 1400 to 1580 MHz frequency band at 1.5 GHz The simulated results for main parameters such as return loss, impedance bandwidth, radiation patterns and gains are also discussed herein. The modeling study shows that such antennas, in simplicity design and supply, and can satisfy GPS application. Two parallel slots are incorporated to disturb the surface flow path, introducing local inductive effect. This antenna is fed by a coaxial feeding tube.

Keywords: bandwidth, electrically small antenna, microstrip, patch antenna, GPS

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Authors: M. S. Agha, A. M. Eshahiry, S. A. Aldabbar, Z. M. Alshahri

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The propagation of microwave is affected by rain and dust particles causing signal attenuation and de-polarization. Computations of these effects require knowledge of the propagation characteristics of microwave and millimeter wave energy in the climate conditions of the studied region. This paper presents effect of wind and humidity on wireless communication such as microwave links in the North West region of Libya (Al-Khoms). The experimental procedure is done on three selected antennae towers (Nagaza station, Al-Khoms center station, Al-Khoms gateway station) for determining the attenuation loss per unit length and cross-polarization discrimination (XPD) change. Dust particles are collected along the region of the study, to measure the particle size distribution (PSD), calculate the concentration, and chemically analyze the contents, then the dielectric constant can be calculated. The results show that humidity and dust, antenna height and the visibility affect both attenuation and phase shift; in which, a few considerations must be taken into account in the communication power budget.

Keywords: : Attenuation, scattering, transmission loss.

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Authors: Sandeep Kumar, Naveen Gupta

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Terahertz (THz) generation has been investigated by beating two cosh-Gaussian laser beams of the same amplitude but different wavenumbers and frequencies through rippled collisionless plasma. The ponderomotive force is operative which is induced due to the intensity gradient of the laser beam over the cross-section area of the wavefront. The electrons evacuate towards a low-intensity regime, which modifies the dielectric function of the medium and results in cross focusing of cosh-Gaussian laser beams. The evolution of spot size of laser beams has been studied by solving nonlinear Schrodinger wave equation (NLSE) with variational technique. The laser beams impart oscillations to electrons which are enhanced with ripple density. The nonlinear oscillatory motion of electrons gives rise to a nonlinear current density driving THz radiation. It has been observed that the periodicity of the ripple density helps to enhance the THz radiation.

Keywords: rippled collisionless plasma, cosh-gaussian laser beam, ponderomotive force, variational technique, nonlinear current density

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Authors: Joanne M. Emmens

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This paper makes use of the case notes of a single psychoanalytically informed psychotherapy of a now 72-year-old man over a four-year period to explore the potential of qualitative data to be incorporated into a research methodology that can contribute theory and knowledge to the wider professional community involved in mental health care. The clinical material arising out of any psychoanalysis provides a potentially rich source of clinical data that could contribute valuably to our historical understanding of both individual and societal traumata. As psychoanalysis is primarily an investigation, it is argued that clinical case material is a rich source of qualitative data which has relevance for sociological and historical understandings and that it can potentially aluminate important ‘gaps’ and collective blind spots that manifest unconsciously and are a contributing factor in the transmission of trauma, silently across generations. By attending to this case material the hope is to illustrate the value of using a psychoanalytic centred methodology. It is argued that the study of individual defences and the manner in which they come into consciousness, allows an insight into group defences and the unconscious forces that contribute to the silencing or un-noticing of important sources (or originators) of mental suffering.

Keywords: dream furniture (Bion) and psychotic functioning, reverie, screen memories, selected fact

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Authors: A. Aboubakr, E. Fehling, S. A. Mourad, M. Omar

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Wind energy is one of the most effective renewable sources especially offshore wind energy although offshore wind technology is more costly to produce. It is well known that offshore wind energy can potentially be very cheap once infrastructure and researches improve. Laterally, the trend is to construct offshore wind energy to generate the electricity form wind. This leads to intensive research in order to improve the infrastructures. Offshore wind energy is the construction of wind farms in bodies of water to generate electricity from wind. The most important part in offshore wind turbine structure is the foundation and its connection with the wind tower. This is the main difference between onshore and offshore structures. Grouted connection between the foundation and the wind tower is the most important part of the building process when constructing wind offshore turbines. Most attention should be paid to the actual grout connection as this transfers the loads safely from tower to foundations and the soil also. In this paper, finite element analyses have been carried out for studying the behaviour of offshore grouted connection for wind turbine structures. ATENA program have been used for non-linear analysis simulation of the real structural behavior thus demonstrating the crushing, cracking, contact between the two materials and steel yielding. A calibration of the material used in the simulation has been carried out assuring an accurate model of the used material by ATENA program. This calibration was performed by comparing the results from the ATENA program with experimental results to validate the material properties used in ATENA program. Three simple patch test models with different properties have been performed. The research is concluded with a result that the calibration showing a good agreement between the ATENA program material behaviors and the experimental results.

Keywords: grouted connection, 3D modeling, finite element analysis, offshore wind energy turbines, stresses

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Authors: Michael Ruiz

Abstract:

Many scholars view the French Revolution as the origins of ‘modern nationalism,’ citing the unprecedented rhetorical power of ‘the nation’ and the emergence of a centralized, modern nation-state during this time. They have also stressed the role of public education in promoting a national language and creating a sense of shared national identity among the masses. Yet as many cultural historians have shown, revolutionary leaders undertook an unprecedented campaign to overhaul French culture in the 1790s in order to cultivate these national ideals and inspire Republican virtues, in what has been called ‘political pedagogy.’ In contrast to scholars of nationalism, who emphasize formal education, revolutionaries attempted to translate abstract ideas of equality and liberty into palpable representations that would inundate everyday life, thereby serving as pedagogical tools. Material culture and everyday life became state apparatuses not just for winning over citizens’ hearts and minds, but for influencing the very formation of the citizen and their innermost ‘self.’ This paper argues that nationalism began in 1789, when ‘the self’ became a political concern and its formation a state project for cultivating political legitimacy. By broadening the meaning of ‘political pedagogy,’ this study brings together scholarship on nationalism with cultural history, thereby highlighting nations and nationalism as banal, palpable, quotidian phenomena and historicizing the complex emergence of ‘modern nationalism.’ Moreover, because the contemporary view of material culture and pedagogy was highly gendered, this study shows the role of culture in the development of a homosocial, male-dominated public sphere in the 19th century. The legacy of the French Revolution’s concern with culture thus persists as much in our vocabulary for political expression as it does in the material world, remaining deeply embedded in everyday day life as a crucial, nearly-invisible, component of nationalism.

Keywords: French Revolution, nationalism, political culture, material culture

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Authors: I. Benyamina, B. Benalioua, M. Mansour, A. Bentouami

Abstract:

The aim of this study is to use a synthetic of the layered double hydroxide as a method of doping of zinc by transition metal. The choice of dopant metal being bismuth. The material has been heat treated at different temperatures then tested on the Photo discoloration of indigo carmine under visible irradiation. In contrast, the diffuse reflectance spectroscopic analysis of the UV-visible heat treated material exhibits an absorbance in the visible unlike ZnO and TiO2 P25. This property let the photocatalytic activity of Bi-ZnO under visible irradiation. Indeed, the photocatalytic effectiveness of Bi-ZnO in a visible light was proved by the total discoloration of indigo carmine solution with intial concentration of 16 mg/L after 90 minutes, whereas the TiO2 P25 and ZnO their discolorations are obtained after 120 minutes.

Keywords: photo-catalysis, doping, AOP, ZnO

Procedia PDF Downloads 370

Authors: Tugba Gurler, Irfan Kurtbas

Abstract:

Roof influences considerably energy demand of buildings. In order to reduce this energy demand, various solutions have been proposed, such as roofs with variable thermal insulation, cool roofs, green roofs, heat exchangers and ventilated roofs, and phase change material (PCM) layered roofs. PCMs suffer from relatively low thermal conductivity despite of their promise of the energy-efficiency initiatives for thermal energy storage (TES). This study not only presents the thermal performance of the concrete roof with PCM layers but also evaluates the products with different design configurations and thicknesses under Central Anatolia Region, Turkey and Nottinghamshire, UK weather conditions. System design limitations and proposed prediction models are discussed in this study. A two-dimensional numerical model has been developed, and governing equations have been solved at each time step. Upper surfaces of the roofs have been modelled with heat flux conditions, while lower surfaces of the roofs with boundary conditions. In addition, suitable roofs have been modeled under symmetry boundary conditions. The results of the designed concrete roofs with PCM layers have been compared with common concrete roofs in Turkey. The UK and the numerical modeling results have been validated with the data given in the literature.

Keywords: phase change material, regional energy demand, roof layers, thermal energy storage

Procedia PDF Downloads 102