Search results for: recycling foundry aluminium alloy

Authors: Georgi Vendramin, Aurea Lúcia, Yamamoto, Carlos Itsuo, Camargo Nogueira, Carlos Eduardo, Lenz, Anderson Miguel, Souza Melegari, Samuel N.

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The thermal performance of a solar water heating with 1.00 m2 flat plate collectors in Cascavel-PR, is which presented in this article, paper presents the solution to leverage the marketing of solar heating systems through detailed constituent materials of the solar collector studies, these abundant materials in construction, such as expanded polyethylene, PVC, aluminum and glass tubes, mixing them with new materials to minimize loss of efficiency while decreasing its cost. The system was tested during months and the collector obtained maximum recorded temperature of outlet fluid of 55 °C, while the maximum temperature of the water at the bottom of the hot water tank was 35 °C. The average daily energy collected was 19 6 MJ/d; the energy supplied by the solar plate was 16.2 MJ/d; the loss in the feed pipe was 3.2 MJ/d; the solar fraction was 32.2%, the efficiency of the collector was 45.6% and the efficiency of the system was 37.8%.

Keywords: recycling materials, energy efficiency, solar collector, solar water heating system

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Authors: Soroor Ghaziof, Wei Gao

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Zn alloy and composite coatings are widely used in buildings and structures, automobile and fasteners industries to protect steel component from corrosion. In this paper, Zn-Ni-Al2O3 nano-composite coatings were electrodeposited on mild steel using a novel sol enhanced electroplating method. In this method, transparent Al2O3 sol was added into the acidic Zn-Ni bath to produced Zn-Ni-Al2O3 nano-composite coatings. The effect of alumina sol on the electrodeposition process, and coating properties was investigated using cyclic voltammetry, XRD, ESEM and Tafel test. Results from XRD tests showed that the structure of all coatings was single γ-Ni5Zn21 phase. Cyclic voltammetry results showed that the electrodeposition overpotential was lower in the presence of alumina sol in the bath, and caused the reduction potential of Zn-Ni to shift to more positive values. Zn-Ni-Al2O3 nano composite coatings produced more uniform and compact deposits, with fine grained microstructure when compared to Zn-Ni coatings. The corrosion resistance of Zn-Ni coatings was improved significantly by incorporation of alumina nano particles into the coatings.

Keywords: Zn-Ni-Al2O3 composite coatings, steel, sol-enhanced electroplating, corrosion resistance

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Authors: Maziar Ramezani, Thomas Neitzert, Timotius Pasang

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This paper aims at experimental and numerical investigation of springback behavior of sheet metals during L-bending process with emphasis on Stribeck-type friction modeling. The coefficient of friction in Stribeck curve depends on sliding velocity and contact pressure. The springback behavior of mild steel and aluminum alloy 6022-T4 sheets was studied experimentally and using numerical simulations with ABAQUS software with two types of friction model: Coulomb friction and Stribeck friction. The influence of forming speed on springback behavior was studied experimentally and numerically. The results showed that Stribeck-type friction model has better results in predicting springback in sheet metal forming. The FE prediction error for mild steel and 6022-T4 AA is 23.8%, 25.5% respectively, using Coulomb friction model and 11%, 13% respectively, using Stribeck friction model. These results show that Stribeck model is suitable for simulation of sheet metal forming especially at higher forming speed.

Keywords: friction, L-bending, springback, Stribeck curves

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Authors: Nauman A. Siddiqui

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High performance requirement of aircrafts and marines industry demands to cater major industrial problems like wetting, high-speed efficiency, and corrosion resistance. These problems can be resolved by producing the hydrophobic surfaces on the metal substrate. By anodization process, the surface of AA 7075 has been modified and achieved a rough surface with a porous aluminum oxide (Al2O3) structure at nano-level. This surface modification process reduces the surface contact energy and increases the liquid contact angle which ultimately enhances the anti-icing properties. Later the Silane and Polyurethane (PU) coatings on the anodized surface have produced a contact angle of 130°. The results showed a good water repellency and self-cleaning properties. Using SEM analysis, micrographs revealed the round nano-porous oxide structure on the substrate. Therefore this technique can help in increasing the speed efficiency by reducing the friction with the outer interaction and can also be declared as a green technique since it is user-friendly.

Keywords: AA 7075, hydrophobicity, silanes, polyurethane, anodization

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Authors: Yasser M. Abd-elrhman, Mohamed A. Gepreel, Kiochi Nakamura, Ahmed Abd El-Moneim, Sengo Kobayashi, Mervat M. Ibrahim

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Titanium alloys are known as highly bio compatible metallic materials due to their high strength, low elastic modulus, and high corrosion resistance in biological media. Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biological and chemical bio compatibility of metallic materials that produce undesirable reactions in implant-adjacent and/or more distant tissues. Electrochemical corrosion behaviors of novel beta titanium alloys, Ti-4.7Mo-4.5Fe, Ti-3Mo-0.5Fe, and Ti-2Mo-0.5Fe were characterized in naturally aerated Ringer’s solution at room temperature compared with common used biomedical titanium alloy, Ti-6Al-4V. The corrosion resistance of titanium alloys were investigated through open circuit potential (OCP), potentiodynamic polarization measurements and optical microscope (OM). A high corrosion resistance was obtained for all alloys due to the stable passive film formed on their surfaces. The new present alloys are promising metallic biomaterials for the future, owing to their very low elastic modulus and good corrosion resistance capabilities.

Keywords: titanium alloys, corrosion resistance, Ringer’s solution, electrochemical corrosion

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Authors: Sandeep Singh Sandhua, Karanvir Singh Ghuman, Arun Kumar

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Stellite 21 is cobalt based super alloy used in improving the wear performance of stainless steel engineering components subjected to harsh environmental conditions. This piece of research focuses on the wear analysis of satellite 21 cladded on AISI 304 L substrate using SMAW process. Bead on plate experiments were carried out by varying current and electrode manipulation techniques to optimize the dilution and microhardness. 80 Amp current and weaving technique was found to be optimum set of parameters for overlaying which were further used for multipass multilayer cladding of AISI 304 L substrate. The wear performance was examined on pin on dics wear testing machine under room temperature conditions. The results from this study show that Stellite 21 overlays show a significant improvement in the frictional wear resistance after TIG remelting. It is also established that low dilution procedures are important in controlling the metallurgical composition of these overlays which has a consequent effect in enhancing hardness and wear resistance of these overlays.

Keywords: surfacing, stellite 21, dilution, SMAW, frictional wear, micro-hardness

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Authors: Jaroslav Fiala, Jaroslav Kaiser, Pavel Zlabek, Vaclav Mentl

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The X-ray diffraction technique was recognized as a useful tool for the assessment of material degradation degree after a long-time service. In many industrial applications materials are subjected to degradation of mechanical properties as a result of real service conditions. The assessment of the remnant lifetime of components and structures is commonly based on correlated procedures including numerous destructive, non-destructive and mathematical techniques that should guarantee reasonable precise assessment of the current damage extent of materials in question and the remnant lifetime assessment. This paper summarizes results of an experimental programme concentrated on mechanical properties degradation of welded components. Steel an Al-alloy test specimens of base metal, containing welds and simple weldments were fatigue loaded at room temperature to obtain Woehler S-N curve. X-ray diffraction technique was applied to assess the degradation degree of material as a result of cyclic loading.

Keywords: fatigue loading, material degradation, steels, AL-alloys, X-ray diffraction

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Authors: Sanaz Mosadeghsedghi, Mathew Hudder, Mohammad Ali Baghbanzadeh, Charbel Atallah, Seyedeh Laleh Dashtban Kenari, Konstantin Volchek

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Lithium has recently been extensively used in lithium-ion batteries (LIBs) for electric vehicles and portable electronic devices. The conventional evaporative approach to recover and concentrate lithium is extremely slow and may take 10-24 months to concentrate lithium from dilute sources, such as geothermal brines. To response to the increasing industrial lithium demand, alternative extraction and concentration technologies should be developed to recover lithium from brines with low concentrations. In this study, a combination of electrocoagulation (EC) and electrodialysis (ED) was evaluated for the recovery of lithium from geothermal brines. The brine samples in this study, collected in Western Canada, had lithium concentrations of 50-75 mg/L on a background of much higher (over 10,000 times) concentrations of sodium. This very high sodium-to-lithium ratio poses challenges to the conventional direct-lithium extraction processes which employ lithium-selective adsorbents. EC was used to co-precipitate lithium using a sacrificial aluminium electrode. The precipitate was then dissolved, and the leachate was treated using ED to separate and concentrate lithium from other ions. The focus of this paper is on the study of ED, including a two-step ED process that included a mono-valent selective stage to separate lithium from multi-valent cations followed by a bipolar ED stage to convert lithium chloride (LiCl) to LiOH product. Eventually, the ED cell was reconfigured using mono-valent cation exchange with the bipolar membranes to combine the two ED steps in one. Using this process at optimum conditions, over 95% of the co-existing cations were removed and the purity of lithium increased to over 90% in the final product.

Keywords: electrochemical separation, electrocoagulation, electrodialysis, lithium extraction

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Authors: Josue Javier Martinez Flores, Jaime Alvarez Quintana

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A thermal rectifier consists of a device which can load a different heat flow which depends on the direction of that flow. That device is a thermal diode. It is well known that heat transfer in solids basically depends on the electrical, magnetic and crystalline nature of materials via electrons, magnons and phonons as thermal energy carriers respectively. In the present research, we have synthesized polycrystalline Ni-Cu alloys and identified the Curie temperatures; and we have observed that by way of secondary phase transitions, it is possible manipulate the heat conduction in solid state thermal diodes via transition temperature. In this sense, we have succeeded in developing solid state thermal diodes with a control gate through the Curie temperature via the activation and deactivation of magnons in Ni-Cu ferromagnetic alloys at room temperature. Results show thermal diodes with thermal rectification factors up to 1.5. Besides, the performance of the electrical rectifiers can be controlled by way of alloy Cu content; hence, lower Cu content alloys present enhanced thermal rectifications factors than higher ones.

Keywords: thermal rectification, Curie temperature, ferromagnetic alloys, magnons

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Authors: Gifty Kumadey, Albert Tchey Agbenyegah

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This study explores the role of stakeholders in developing a sustainable supply chain policy framework in Ghana's pharmaceutical industry. It employs a qualitative research design to analyze policy documents, academic articles, and reports, shedding light on stakeholder involvement. The findings highlight the contributions of government agencies, regulatory bodies, pharmaceutical companies, suppliers, and civil society organizations. Key policies such as green procurement, waste management, and recycling initiatives are identified. However, challenges such as limited transparency, supplier engagement, and regulatory complexity impede implementation. The study recommends strengthening collaboration and promoting transparency to overcome these challenges. The findings provide valuable insights for policymakers, industry stakeholders, and researchers seeking to advance sustainable supply chain practices in Ghana's pharmaceutical industry.

Keywords: stakeholders, sustainable supply chain, policy framework, pharmaceutical industry

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Authors: B. Käfer, V. K. Bheemineni, H. Lammer, M. Kotnik, F. O. Riemelmoser

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Axial compression tests are performed on circular tubes made of Aluminum EN AW 6060 (AlMgSi0.5 alloy) in T66 state. All the received tubes have the uniform outer diameter of 40mm and thickness of 1.5mm. Two different lengths 100mm and 200mm are used in the analysis. After performing compression tests on the uniform tube, important crashworthy parameters like peak force, average force, crush efficiency and energy absorption are measured. The present paper has given importance to increase the percentage of crush efficiency without decreasing the value energy absorption of a tube, so a circumferential notch was introduced on the top section of the tube. The effects of position and cut-out lengths of a circumferential notch on the crush efficiency are well explained with relative deformation modes and force-displacement curves. The numerical simulations were carried on the software tool ANSYS/LS-DYNA. It is seen that the numerical results are reasonably good in agreement with the experimental results. 

Keywords: crash box, Notch triggering, energy absorption, FEM simulation

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Authors: Florian Kleber, Martin Kampel

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The increasing demand of gallium, indium and rare-earth elements for the production of electronics, e.g. solid state-lighting, photovoltaics, integrated circuits, and liquid crystal displays, will exceed the world-wide supply according to current forecasts. Recycling systems to reclaim these materials are not yet in place, which challenges the sustainability of these technologies. This paper proposes a multispectral imaging system as a basis for a vision based recognition system for valuable components of electronics waste. Multispectral images intend to enhance the contrast of images of printed circuit boards (single components, as well as labels) for further analysis, such as optical character recognition and entire printed circuit board recognition. The results show that a higher contrast is achieved in the near infrared compared to ultraviolet and visible light.

Keywords: electronics waste, multispectral imaging, printed circuit boards, rare-earth elements

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Authors: Ryu Wonjin, Choi Hyeok, Park Joonhong

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Overlay welding for improving surface properties is a method of the surface treatments which improve surface properties of material by welding materials of alloy having corrosion resistance on the basic material surface. Overlay welding affects contents of chemical components and weld hardness from different parts by dilution of the lamination layer thickness, and it determines surface properties. Therefore, overlay welding has to take into account thickness of the lamination layers with the process. As a result in this study examined contents of Fe, weldability of the base metal and monel materials, hardness and surface flatness from different parts according to each the lamination layer parameters by overlay welding monel materials with corrosion resources to the base material of carbon steel. Through this, evaluated effect by the lamination layer parameters of welding and presented decision methods of the lamination layer parameters of the overlay welding by the purpose of use.

Keywords: clad pipe, lamination layer parameters, monel, overlay welding

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Authors: Zoltán Weltsch, József Hlinka, Eszter Kókai

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The temperature dependence of wettability (wetting angle, Θ (T)) for Ag-based melts on graphite and Al2O3 substrates is compared. Typical alloying effects are found, as the Ag host metal is gradually replaced by various metallic elements. The essence of alloying lies in the change of the electron/atom (e/a) ratio. This ratio is also manifested in the shift of wetting angles on the same substrate. Nevertheless, the effects are partially smeared by other (metallurgical) factors, like the interaction between the oxygen-alloying elements and by the graphite substrate-oxygen interaction. In contrast, such effects are not pronounced in the case of Al2O3 substrates. As a consequence, Θ(T) exhibits an opposite trend in the case of two substrates. Crossovers of the Θ(T) curves were often found. The positions of crossovers depend on the chemical character and concentration of solute atoms. Segregation and epitaxial texture formation after solidification were also observed in certain alloy drops, especially in high concentration range. This phenomenon is not yet explained in every detail.

Keywords: contact angle, graphite, silver, soldering, solid solubility, substrate, temperature dependence, wetting

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Authors: Mahsa Namvari, Kari Ullakko

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It is well-known that the Co-doping of ferromagnetic shape memory alloys (FSMAs) is a crucial tool to control their multifunctional properties. The present work investigates the use of small quantities of Co to fine-tune the transformation, structure, microstructure, mechanical and magnetic properties of the polycrystalline Ni₄₉.₈Mn₂₈.₅Ga₂₁.₇ (at.%) alloy, At Co concentrations of 1-1.5 at.%, a microstructure with an average grain size of about 2.00 mm was formed with a twin structure, enabling the experimental observation of magnetic-field-induced twin variant rearrangement. At higher levels of Co-doping, the grain size was essentially reduced, and the crystal structure of the martensitic phase became 2M martensite. The decreasing grain size and changing crystal structure are attributed to the progress of γ-phase precipitates. Alongside the academic aspect, the results of the present work point to the commercial advantage of fabricating 10M Co-doped Ni-Mn-Ga actuating elements made from large grains of polycrystalline ingots obtained by a standard melting facility instead of grown single crystals.

Keywords: Ni-Mn-Ga, ferromagnetic shape memory, martensitic phase transformation, grain growth

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Authors: Anusha Chanda, Reenu Singh

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Packaging is one of the major contributors to global waste. While efforts are being made to switch to more sustainable types of packaging, such as switching from single use plastics to paper, not all polluting materials, have been rethought in terms of recycling. Minimalism in packaging design can help reduce the amount of waste produced greatly. While online companies have shifted to using cardboard boxes for packages, a large amount of waste in still generated from other materials affiliated with cardboard packaging, such as tape, bubble wrap, plastic wrap, among others. Minimalism also works by reducing extra packaging and increasing the reusability of the material. This paper looks at research related to minimalism in packaging design, minimalism, and sustainability. A survey was conducted in order to find out the different ways in which minimalism can be implemented in packaging design. Information gathered from the research and responses from the survey was used to ideate product design alternatives for sustainable substitutes for bubble wrap in packaging. This would help greatly reduce the amount of packaging waste and improve environmental quality.

Keywords: environment, minimalism, packaging, product design, sustainable

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Authors: Lemoussi Somia, Ouali Mohammed, Zemirline Adel

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In precision engineering, including precision positioning, micro-manipulation, robotic systems... a majority of these applications actuated by piezo stack used the compliant amplifier mechanism to amplifying motion and guiding it as needed utilize the flexibility of their components, in this paper, we present a novel approach introducing a symmetric structure comprising three stages, featuring rectangular flexure hinges with a compact size of 77mm×42mm×10mm. This design provides the capability for rotation, translation or a combination of both movements in both directions. The system allows for a displacement of 2107.5 μm when the input displacement of PZT is 50 μm while considering the material constraints of the aluminum alloy (7075 T6) which has a maximum admissible stress of 500 MPa However, our proposed design imposes additional constraints to ensure the stress remains below 361 MPa for optimal performance. These findings were obtained through finite element simulations conducted using ANSYS Workbench. Furthermore, our module facilitates precise control of various components within robotic systems, allowing for adjustable speeds based on specific requirements or desired outcomes.

Keywords: robotic, piezoelectric, compliant mechanism, flexure hinge

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Authors: Joon-Suk Kim, Hae-Woo Lee

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This study discusses the effect of welding heat input on intergranular corrosion of the weld metal of Inconel 625 alloy. A specimen of Inconel 625 with a weld metal that controlled welding heat input was manufactured, and aging heat treatment was conducted to investigate sensitization by chromium carbides. The electrochemical SL and DL EPR experiments, together with the chemical ferric sulfate-sulfuric acid and nitric acid tests, were conducted to determine intergranular corrosion susceptibility between the specimens. In the SL and DL EPR experiments, specimens were stabilized in the weld metal, and therefore intergranular corrosion susceptibility could not be determined. However, in the ferric sulfate-sulfuric acid and nitric acid tests, the corrosion speed increased as heat input increased. This was because the amount of diluted Fe increased as the welding heat input increased, leading to microsegregation between the dendrites, which had a negative effect on the corrosion resistance.

Keywords: Inconel 625, weling, overlay, heat input, intergranular corrosion

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Authors: Yee-Ting Lee, Jyun-Rong Zhuang, Wen-Hsin Hsieh, An-Shik Yang

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Additive manufacturing (AM) is increasingly crucial in biomedical and aerospace industries. As a recently developed AM technique, selective laser melting (SLM) has become a commercial method for various manufacturing processes. However, the molten pool configuration during SLM of metal powders is a decisive issue for the product quality. It is very important to investigate the heat transfer characteristics during the laser heating process. In this work, the finite element method (FEM) software ANSYS^® (work bench module 16.0) was used to predict the unsteady temperature distribution for resolving molten pool dimensions with consideration of temperature-dependent thermal physical properties of TiAl6V4 at different laser powers and scanning speeds. The simulated results of the temperature distributions illustrated that the ratio of laser power to scanning speed can greatly influence the size of molten pool of titanium alloy powder for SLM development.

Keywords: additive manufacturing, finite element method, molten pool dimensions, selective laser melting

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Authors: Gavin Gengan, Hsein Kew

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Glass from varying recycling processes is considered a material that can be used as aggregate. Waste glass is available from different sources and has been used in the construction industry over the last decades. This current study aims to use recycled glass as a partial replacement for conventional aggregate materials. The experimental programme was designed to optimise the mechanical properties of structural concrete made with recycled glass aggregates (GA). NA (natural aggregates) was partially substituted by GA in a mix design of concrete of 30N/mm2 in proportions of 10%, 20%, and 25% 30%, 40%, and 50%. It was found that with an increasing proportion of GA, there is a decline in compressive strength. The optimum percentage replacement of NA by GA is 25%. The heat of hydration was also investigated with thermocouples placed in the concrete. This revealed an early acceleration of hydration heat in glass concrete, resulting from the thermal properties of glass. The gain in the heat of hydration and the better bonding of glass aggregates together with the pozzolanic activity of the finest glass particles caused the concrete to develop early age and long-term strength higher than that of control concrete

Keywords: concrete, compressive strength, glass aggregates, heat of hydration, pozzolanic

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Authors: Sara Blanc, José V. Benlloch-Dualde, Laura Grindei, Ana C. Torres, Angélica Monteiro

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This paper presents a study that leads a new experience by introducing digital learning applied to a case study focused on primary and secondary school garden-based education. The approach represents an example of interaction among different education and research agents at different countries and levels, such as universities, public and private research, and schools, to get involved in the implementation of education for sustainable development that will make students become more sensible to natural environment, more responsible for their consumption, more aware about waste reduction and recycling, more conscious of the sustainable use of natural resources and, at the same time, more ‘digitally competent’. The experience was designed attending to the European digital education context and OECD directives in transversal skills education. The paper presents the methodology carried out in the study as well as outcomes obtained from experience.

Keywords: school gardens, primary education, secondary education, science technology and innovation in education, digital learning, sustainable development goals, university, knowledge transference

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Authors: Taher El-Bitar, Maha El-Meligy, Eman El-Shenawy, Almosilhy Almosilhy, Nader Dawood

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The steel contains 0.3% C and 0.004% B, beside Mn, Cr, Mo, and Ni. The alloy was processed by using 20-ton capacity electric arc furnace (EAF), and then refined by ladle furnace (LF). Liquid steel was cast as rectangular ingots. Dilatation test showed the critical transformation temperatures Ac₁, Ac₃, M_s and M_f as 716, 835, 356, and 218 °C. The ingots were austenitized and soaked and then rough rolled to thin slabs with 80 mm thickness. The thin slabs were then reheated and soaked for finish rolling to 6.0 mm thickness plates. During the rough rolling, the roll force increases as a result of rolling at temperatures less than recrystallization temperature. However, during finish rolling, the steel reflects initially continuous static recrystallization after which it shows strain hardening due to fall of temperature. It was concluded that, the steel plates were successfully heat treated by quenching-tempering at 250 ºC for 20 min.

Keywords: armor steel, austenitizing, critical transformation temperatures (CTTs), dilatation curve, martensite, quenching, rough and finish rolling processes, soaking, tempering, thermo-mechanical processing

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Authors: Juliane P. De Oliveira, Carlos H. Dos Santos, Marcia Shoji, Maria E. C. Ferreira, Natalia U. Yamaguchi

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The construction sector is considered a major generator of environmental impacts due to the high consumption of natural resources and waste generation. Thus, this article aims to evaluate the performance of a concrete produced by the partial and total replacement of natural coarse aggregate by recycled coarse aggregate, derived from the concrete residue of buildings and demolitions. The study was made by comparing the compressive strength and absorption of three different concrete traces, keeping the water/cement factor of 0.60 and changing only the proportions of recycled coarse aggregate between 0%, 50% and 100%. Traces 50% and 100% obtained good results by comparing the actual specific mass, because the material used is lighter to the natural coarse aggregate. It was concluded that the concrete produced with recycled aggregates, even with inferior results, can be used where it is not needed a structural function, giving an adequate destination to the construction and demolition waste and consequently reducing the extraction and consumption of natural resources.

Keywords: green concrete, recycled aggregate, recycling, sustainable development

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Authors: Adejo Andrew Ojonugwa, Jomboh Jeff Kator, Garkida Adele Dzikwi

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This study investigates the behaviour of textured glass coat to chemical reactions upon application. Samples of textured glass coat developed from mixed post consumer glass were subjected to pH test (ASTM D5464), Chemical resistance test (ASTM D3260 and D1308), Adhesion test (ASTM D3359), and Abrasion test (ASTM D4060). Results shows a pH of 8.50, Chemical resistance of 5% flick rate when reacted with Sodium hydroxide (NaOH), a 3%, 5%, 10%, and 15% discolouration when reacted with Magnesium hydroxide (Mg(OH)2), Hydrogen fluoride (HF), Potassium hydroxide (KOH) and NaOH respectively, an adhesion of 4A and abrasion of 0.2g. The results confirm that the developed textured glass coat is in line with the standard pH range of 8-9, resistant to acid and base except for HF, NaOH, and Mg(OH)₂, good adhesion and abrasion properties, thereby making the coat resistant to chemical degradation and a good engineering material.

Keywords: chemical durability, glass-coat, building, recycling

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Authors: Theena Thayalan, K. N. Ramesh Babu

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Machining induced residual stress (RS) is one of the most important surface integrity parameters that characterize the near surface layer of a mechanical component, which plays a crucial role in controlling the performance, especially its fatigue life. Since experimental determination of RS is expensive and time consuming, it would be of great benefit if they could be predicted. In such case, it would be possible to select the cutting parameters required to produce a favorable RS profile. In the present study, an effort has been made to develop a 'two dimensional finite element model (FEM)' to simulate orthogonal cutting process and to predict surface and sub-surface RS using the commercial FEA software DEFORM-2D. The developed finite element model has been validated through experimental investigation of RS. In the experimentation, the orthogonal cutting tests were carried out on AISI 4340 by varying the cutting speed (VC) and uncut chip thickness (f) at three levels and the surface & sub-surface RS has been measured using XRD and Electro polishing techniques. The comparison showed that the RS obtained using developed numerical model is in reasonable agreement with that of experimental data.

Keywords: FEM, machining, residual stress, XRF

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Authors: G. Farkas, K. Mathis, J. Pilch, P. Minarik

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Deformation mechanisms in an Mg-Al-Ca alloy reinforced with short alumina fibres were studied by acoustic emission and in-situ neutron diffraction method. The fibres plane orientation with respect to the loading axis was found to be a key parameter, which influences the acting deformation processes, such as twinning or dislocation slip. In-situ neutron diffraction tests were measured at different temperatures from room temperature (RT) to 200°C. The measurement shows the lattice strain changes in the matrix and also in the reinforcement phase depending on macroscopic compressive deformation and stress. In case of parallel fibre plane orientation, the increment of compressive lattice strain is lower in the matrix and higher in the fibres in comparison to perpendicular fibre orientation. Furthermore, acoustic emission results indicate a larger twinning activity and more frequent fibre cracking in sample with perpendicular fibre plane orientation. Both types of mechanisms are more dominant at elevated temperatures.

Keywords: neutron diffraction, acoustic emission, magnesium based composite, deformation mechanisms

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Authors: Reza Mokhtari Malekabadi, Leila Jalalabadi, Zahra Kiyani Ghaleh No

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Today, systems of management and urban planning, attempt to reach more sustainable development through monitoring developments, urban development and development plans. Monitoring of changes in the urban places and sustainable urban development accounted a base for the realization of worthy goals urban sustainable development. The importance of women in environmental protection programs is high enough that in 21 agenda has been requested from all countries to allocate more shares to women in their policies. On the other hand, urban waste landfill has become one of the environmental concerns in modern cities. This research assumes that the impact of women on recycling, reduction and proper waste landfill is much more than men. For this reason, three districts; Yousef Abad, Heshmatieh and Nezam Abad are gauged through questionnaire and using the analytical research hypothesis model. This research will be categorized as functional research. The results have shown that noticing the power of women, their participation towards realization of the development objectives and programs can be used in solving their problems.

Keywords: citizens, urban, environmental, sustainability, solid waste, Tehran

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Authors: Maria Santana, Jose Estaire

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Even though recycling strategies are becoming more important in recent years, there is still a huge amount of industrial by-products that are the disposal of at landfills. Due to the size, possible dangerous composition, and heterogeneity, most of the wastes are located at landfills without a basic geotechnical characterization. This lack of information may have an important influence on the correct stability calculations. This paper presents the results of geotechnical characterization of some industrial wastes disposed at one landfill. The shear strength parameters were calculated based on direct shear test results carried out in a large shear box owned by CEDEX, which has a shear plane of 1 x 1 m. These parameters were also compared with the results obtained in a 30 x 30 cm shear box. The paper includes a sensitive analysis of the global safety factor of the landfill's overall stability as a function of shear strength variation. The stability calculations were assessed for various hydrological scenarios to simulate the design and performance of the leachate drainage system. The characterization was completed with leachate tests to study the potential impact on the environment.

Keywords: industrial wastes, landfill, leachate tests, stability

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Authors: Mohammad S. Rouhi, Magdalena Juntikka

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Processing of polymer fiber composites has a remarkable influence on their mechanical performance. These mechanical properties are even more influenced when using recycled reinforcement. Therefore, we place particular attention on the evaluation of micromechanical models to estimate the mechanical properties and compare them against the experimental results of the manufactured composites. For the manufacturing process, an epoxy matrix and carbon fiber production cut-offs as reinforcing material are incorporated using a vacuum infusion process. In addition, continuous textile reinforcement in combination with the epoxy matrix is used as reference material to evaluate the kick-down in mechanical performance of the recycled composite. The experimental results show less degradation of the composite stiffness compared to the strength properties. Observations from the modeling also show the same trend as the error between the theoretical and experimental results is lower for stiffness comparisons than the strength calculations. Yet still, good mechanical performance for specific applications can be expected from these materials.

Keywords: composite recycling, carbon fibers, mechanical properties, micromechanics

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Authors: O. Crisan, A. D. Crisan, I. Mercioniu, R. Nicula, F. Vasiliu

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FePt-based systems are currently under scrutiny for their possible use as future materials for perpendicular magnetic recording. Another possible application is in the field of permanent magnets without rare-earths, magnets that are capable to operate at higher temperatures than the classic Nd-Fe-B magnets. Within this work, FeCoPt alloys prepared by rapid solidification from the melt are structurally and magnetically characterized. Extended transmission electron microscopy analysis shows the high degree of L10 ordering. X-ray diffraction is used to characterize the phase structure and to obtain the structural parameters of interest for L10 ordering. Co-existence of hard CoFePt and CoPt L10 phases with the soft fcc FePt phase is obtained within a refined microstructure made of alternatively disposed grains of around 5 to 20 nm in size. Magnetic measurements show increased remanence close to the parent L10 FePt phase and not so high coercivity due to the significant presence of the soft magnetic constituent phase. A Curie temperature of about 820K is reported for the FeCoPt alloy.

Keywords: melt-spinning, FeCoPt alloys, high-resolution electron microscopy (HREM), ordered L10 structure

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