Search results for: Construction materials

Authors: L. Sasikala, Bhaarathi Dhurai

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Increase in antibiotic resistance bacteria leads to the development of active wound dressings, which absorb any bodily fluid, evaporation of moisture at a certain rate and can be easily removed after healing. Natural materials like chitosan, herbs, and honey have number of active materials present in them to accelerate wound healing and to arrest wound in infections. Hence with the advantages of biomaterials, a film was prepared using chitosan and honey. There are a lot of practical considerations with respect to honey. Honey exerts many beneficial actions on the wound surface only when it remains. The attempts to hold honey on the surface of the wound remain a question because honey becomes a very runny liquid when it comes to body temperature. Hence, this research was focused on development of a new form of wound dressing, by holding honey on the wound surface in different form and also which has a combined effect of manuka (Leptospermum scoparium) honey and chitosan. Chitosan-honey film was prepared using casting technique. Films were prepared in different variations; with acetic acid and with lactic acid; with and without honey. In summary, the film produced from 2% chitosan- 1% lactic acid as a solvent, with 10% honey shows optimum inclined values in all the tests, like thickness, folding endurance, weight, water vapor transmission, tensile strength, swelling ratio and antimicrobial activity, with specific reference to wound dressings. The film has water vapor transmission of 1680 g/m²/day, water absorption of 225%, tensile strength of 39.1N/mm² and elongation of 50.3%. There is a notable inhibition zone of 29 mm against S. aureus and 24 mm against E. coli in the case of chitosan-lactic acid-honey film. The film also arrests, microbes transmitting from the outside environment to wound bed, which can be used as an effective wound dressing material.

Keywords: casting technique, chitosan, honey, film, wound dressings

Procedia PDF Downloads 251

Authors: Hamid Fazlollahi, Behzad Rafezy, Hassan Afshin

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There masonry infill increases the stiffness of reinforced concrete frames, thus increasing the force of the earthquake also the interaction between the frame and infill, which can have devastating effects on structures. In contrast presence of infill to increase the structural strength and stability. What is seen in the construction and design of structures has largely ignored the effects of infill and regardless infill structure and its positive and negative effects analyzes and designs, that it is not economically justified and the positive effects of positive infill to be increased and almost all of the useful capacity of moment frames used for infill. In this paper, by using ABAQUS software, reinforced concrete frame with masonry infill will be modeled, then add a mechanical rubber element to modify the interaction between the frame and infill and thus reduce the losses caused by the presence of infill explains. Finally, by comparing the analytical curves, benefits of this approach we will study and to present the results of the interaction between the frame and infill masonry needs modification and methods it will provide.

Keywords: masonry infill, mechanical rubber, reinforced concrete frame, interaction, ductility

Procedia PDF Downloads 457

Authors: Zhuoqun Sun, Francisco Sierra, A. Booth

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With BIM rapidly implemented in the design and construction stage of a project, researchers begin to focus on improving the operation and maintenance stage with the aid of BIM. Since the increasing amount of electronic equipment installed in the building, building management system becomes mainstream for controlling a building, especially in higher education institutions that can play an important role in terms of reducing carbon emission and improving energy efficiency. Currently, an approach to integrate BIM and BMS to improve HEIs facility management has not been established yet. Thus, this paper aims to analyse the benefits, issues, and trends of BIM and BMS integration and their application in HEIs. A systematic literature review was carried out on SCOPUS by applying the PRISMA methodology. 73 articles have been chosen based on keywords, abstracts, and the full content of the articles. The benefit and existed issues from the articles are analysed. The review shows the need to develop a tool to improve facility management through BIM BMS integration.

Keywords: BIM, BMS, HEIs, review

Procedia PDF Downloads 165

Authors: Hsiu Hua Hu

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Digital transformation has widely affected various industries. It provides technological innovation, process redesign, new business model construction, and talent value creation. This transformation not only allows organizations to obtain and deploy specific technologies and methods suitable for organizational reengineering but also is an important way to solve management problems in human resource (HR) reengineering, business efficiency, and process redesign. In this study, we present the results of a qualitative study that offers insight into a series of key feature of reengineering related to the digital transformation and how to create talent value when the companies successfully perform digital transformation and human resource reengineering, which is led by business digitalization strategies including talent planning, talent acquisition, talent adjustment, and talent development. Drawing from the qualitative investigation findings, we built an inductive model of HR reengineering, which aims to provide research and practical references on future digital transformation and management inquiry.

Keywords: talent value creation, digital transformation, HR reengineering, qualitative study

Procedia PDF Downloads 161

Authors: Anna Veres

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People’s ability to adapt to a constantly changing environment is essential. Career adaptability is central to Career Construction Theory, where proper adaptation to new situations, changing environments, and jobs require adequate career development. Based on current career theories and the possibilities offered by digital technology, the primary goal of this study is to develop career adaptability through an online tool. Its secondary goal is to apply for an online career intervention program and explore its developmental possibilities. A total of 132 university students from the bachelor program took part in the study, from which 65 students received a four-week online career intervention, while 67 participants formed the control group. Based on the results, it can state that career adaptability can be developed, and there is a great demand and interest from university students to use career-related programs on online platforms. Career interventions should be performed online as well if there is suitable software and a well-constructed program. Limitations and further implications are discussed.

Keywords: career adaptability, career development, online career intervention, university students

Procedia PDF Downloads 144

Authors: Zohreh Derikvand

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Nanoreactors Zr-MCM-41were prepared via the reaction of ZrOCl2, Fumed silica, sodium hydroxide and cethyltrimethyl ammonium bromide under hydrothermal condition. The prepared nanoreactors were characterized by FT-IR spectroscopy, X-ray diffraction (XRD), Scanning electron micrographs (SEM) and nitrogen adsorption-desorption. The XRD pattern of Zr-MCM-41 exhibits a high-intensity (100) and two low-intensity reflections (110 and 200) which are characteristic of hexagonal structure, exhibiting the long-range order and good textural uniformity of mesoporous structure. Based on the green chemistry approach, we report an efficient and environmentally benign protocol to study the catalytic activity of Zr-MCM-41 in the Biginelli type reactions initially. Nanoreactors Zr-MCM-41 were used as highly recoverable and reusable catalyst for synthesis of 3,4-dihydropyrimidin-2(1H)-one, octahydroquinazolinone, benzimidazolo-quinazolineone and 4,6-diarylpyrimidin-2(1H)-one. The methodology offers several advantages such as short reaction time, high yields and simple operation. The catalyst was active up to three cycles.

Keywords: Zr-MCM-41 nanoreactors, Biginelli like reactions, 3, 4-dihydropyrimidin-2(1H)-ones, ctahydroquinazolinones

Procedia PDF Downloads 209

Authors: Shidokht Rashiddadash, Mojtaba Sadighi, Soheil Dariushi

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Since sandwich structures are used in many areas ranging from ships, trains, automobiles, aircrafts, bridge and building, connecting sandwich structures is necessary almost in all industries. So application of metallic joints between sandwich panels is increasing. Various joining methods are available such as mechanically fastened joints (riveting or bolting) or adhesively bonded joints and choosing one of them depends on the application. In this research, sandwich specimens were fabricated with two different types of metallic connections with dissimilar geometries. These specimens included beams and plates and were manufactured using glass-epoxy skins and aluminum honeycomb core. After construction of the specimens, bending and low velocity impact tests were executed on them and the behaviors of specimens were discussed. Numerical models were developed using LS-DYNA software and validated with test results. Finally, parametric studies were performed on the thicknesses and lengths of two connections by employing the numerical models.

Keywords: connection, honeycomb, low velocity impact, sandwich panel, static test

Procedia PDF Downloads 62

Authors: Osama Hidayat, Yoshitaka Kajiat

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Kabul is a city that is highly representative of Afghanistan’s rapid urbanization process. As the city rapidly expands, there are enormous challenges to the sustainable use of land resources. This paper evaluates land use change and urban spatial expansion, from 1950 to 2016, in Kabul the capital of Afghanistan, using satellite images, field observation, and socio-economic data. The discussion covers the reduction in rural-to-urban land conversion, the delineation of urban growth boundaries, arable land reclamation and the establishment of farmland protection areas, urban upgrading, and the investigation and prosecution of illegal construction. This paper considers the aspects of urbanization and land management systems in Afghanistan. Efficient frames are outlined in Kabul for the following elements: governmental self-restraint and policy modification. The paper concludes that Kabul’s sustainable land use practices can provide a reference for other cities in Afghanistan.

Keywords: urban land expansion, urbanization, land use policy, sustainable development

Procedia PDF Downloads 170

Authors: Shengwei Zhu, Alireza Afshani, Hirokazu Akagi

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Ground surface settlement induced by shield tunneling is addressing increasing attention as shield tunneling becomes a popular construction technique for tunnels in urban areas. This paper discusses a 2D longitudinal FEM simulation of a tunneling case study in Japan (Tokyo Metro Yurakucho Line). Tunneling-induced field data was already collected and is used here for comparison and evaluating purposes. In this model, earth pressure, face pressure, backfilling grouting, elastic tunnel lining, and Mohr-Coulomb failure criterion for soil elements are considered. A method called ‘stress relaxation’ is also exploited to simulate the gradual tunneling excavation. Ground surface settlements obtained from numerical results using the introduced method are then compared with the measurement data.

Keywords: 2D longitudinal FEM model, tunneling case study, stress relaxation, shield tunneling excavation

Procedia PDF Downloads 335

Authors: Amelia Frickey, Timothy (TJ) Sheridan, Angelica Rossi, Bahar Aliakbarian

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The growth of large food supply chains demanded improved end-to-end traceability of food products, which has led to companies being increasingly interested in using smart technologies such as Radio Frequency Identification (RFID)-enabled packaging to track items. As technology is being widely used, there are several technological or economic issues that should be overcome to facilitate the adoption of this track-and-trace technology. One of the technological challenges of RFID technology is its sensitivity to different environmental form factors, including packaging materials and the content of the packaging. Although researchers have assessed the performance loss due to the proximity of water and aqueous solutions, there is still the need to further investigate the impacts of food products on the reading range of RFID tags. However, to the best of our knowledge, there are not enough studies to determine the correlation between RFID tag performance and food beverages properties. The goal of this project was to investigate the effect of the solution properties (pH and conductivity) and different packaging materials filled with food-like water-based solutions on the performance of an RFID tag. Three commercially available ultra high-frequency RFID tags were placed on three different bottles and filled with different concentrations of water-based solutions, including sodium chloride, citric acid, sucrose, and ethanol. Transparent glass, Polyethylneterephtalate (PET), and Tetrapak® were used as the packaging materials commonly used in the beverage industries. Tag readability (Theoretical Read Range, TRR) and sensitivity (Power on Tag Forward, PoF) were determined using an anechoic chamber. First, the best place to attach the tag for each packaging material was investigated using empty and water-filled bottles. Then, the bottles were filled with the food-like solutions and tested with the three different tags and the PoF and TRR at the fixed frequency of 915MHz. In parallel, the pH and conductivity of solutions were measured. The best-performing tag was then selected to test the bottles filled with wine, orange, and apple juice. Despite various solutions altering the performance of each tag, the change in tag performance had no correlation with the pH or conductivity of the solution. Additionally, packaging material played a significant role in tag performance. Each tag tested performed optimally under different conditions. This study is the first part of comprehensive research to determine the regression model for the prediction of tag performance behavior based on the packaging material and the content. More investigations, including more tags and food products, are needed to be able to develop a robust regression model. The results of this study can be used by RFID tag manufacturers to design suitable tags for specific products with similar properties.

Keywords: smart food packaging, supply chain management, food waste, radio frequency identification

Procedia PDF Downloads 118

Authors: L. Mentar, O. Baka, M. R. Khelladi, A. Azizi

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Zinc oxide (ZnO), as a transparent semiconductor with a wide band gap of 3.4 eV and a large exciton binding energy of 60 meV at room temperature, is one of the most promising materials for a wide range of modern applications. With the development of film growth technologies and intense recent interest in nanotechnology, several varieties of ZnO nanostructured materials have been synthesized almost exclusively by thermal evaporation methods, particularly chemical vapor deposition (CVD), which generally require a high growth temperature above 550 °C. In contrast, wet chemistry techniques such as hydrothermal synthesis and electro-deposition are promising alternatives to synthesize ZnO nanostructures, especially at a significantly lower temperature (below 200°C). In this study, the electro-deposition method was used to produce zinc oxide (ZnO) nanostructures on fluorine-doped tin oxide (FTO)-coated conducting glass substrate from chloride bath. We present the influence of KCl concentrations on the electro-deposition process, morphological, structural and optical properties of ZnO nanostructures. The potentials of electro-deposition of ZnO were determined using the cyclic voltammetry. From the Mott-Schottky measurements, the flat-band potential and the donor density for the ZnO nanostructure are determined. Field emission scanning electron microscopy (FESEM) images showed different sizes and morphologies of the nanostructures which depends on the concentrations of Cl-. Very netted hexagonal grains are observed for the nanostructures deposited at 0.1M of KCl. X-ray diffraction (XRD) study confirms the Wurtzite phase of the ZnO nanostructures with a preferred oriented along (002) plane normal to the substrate surface. UV-Visible spectra showed a significant optical transmission (~80%), which decreased with low Cl-1 concentrations. The energy band gap values have been estimated to be between 3.52 and 3.80 eV.

Keywords: Cl-, electro-deposition, FESEM, Mott-Schottky, XRD, ZnO

Procedia PDF Downloads 291

Authors: HoYoung Son, DongHoon Shin, WooYoung Jung

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This study presented the seismic fragility framework of concrete weir structure subjected to strong seismic ground motions and in particular, concrete aging condition of the weir structure was taken into account in this study. In order to understand the influence of concrete aging on the weir structure, by using probabilistic risk assessment, the analytical seismic fragility of the weir structure was derived for pre- and post-deterioration of concrete. The performance of concrete weir structure after five years was assumed for the concrete aging or deterioration, and according to after five years’ condition, the elastic modulus was simply reduced about one–tenth compared with initial condition of weir structures. A 2D nonlinear finite element analysis was performed considering the deterioration of concrete in weir structures using ABAQUS platform, a commercial structural analysis program. Simplified concrete degradation was resulted in the increase of almost 45% of the probability of failure at Limit State 3, in comparison to initial construction stage, by analyzing the seismic fragility.

Keywords: weir, FEM, concrete, fragility, aging

Procedia PDF Downloads 487

Authors: Dejan Metodijeski, Elizabeta Mitreva, Nako Taskov, Oliver Filiposki

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Tourism development strategies are an important link in the tourism policy that is used to make its management better and easier. A public-public partnership (PUP) is a partnership between two or more public authorities or between a public authority and any non-profit organization with the goal of providing services and facilities or transferring technical skills. The paper presents this kind of partnership between two public authorities in Macedonia, the Municipality of Gazi Baba on one hand, and the University of Goce Delcev on the other. The main idea of this partnership is the development of a tourism strategy for the Municipality of Gazi Baba by the University on one side, and on the other, the construction of a mini park in the court of the University by the Municipality. This paper presents the causes and analyzes the procedures relating to this partnership and the methodology of the tourism development strategy. It contains a relevant literature review related to PUPs and tourism development strategy. The results and benefits of this partnership are presented with figures.

Keywords: public-public partnership, tourism development strategy, municipality of Gazi Baba, Macedonia

Procedia PDF Downloads 368

Authors: Nkiru I. Ibeakuzie, Paul D. J. Watson, John F. Pescatore

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In roadway construction, the cost of soil-cement stabilization per unit area is significantly influenced by the binder content, hence the need to optimise cement usage. This research work will characterize the influence of soil fractal geometry on properties of cement-stabilized soil, and strive to determine a correlation between mechanical proprieties of cement-stabilized soil and the mass fractal dimension Dₘ indicated by particle size distribution (PSD) of aggregate mixtures. Since strength development in cemented soil relies not only on cement content but also on soil PSD, this study will investigate the possibility of reducing cement content by changing the PSD of soil, without compromising on strength, reduced permeability, and compressibility. A series of soil aggregate mixes will be prepared in the laboratory. The mass fractal dimension Dₘ of each mix will be determined from sieve analysis data prior to stabilization with cement. Stabilized soil samples will be tested for strength, permeability, and compressibility.

Keywords: fractal dimension, particle size distribution, cement stabilization, cement content

Procedia PDF Downloads 225

Authors: Safiah Ahmed Madkhali

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The grammatical relation object has not attracted the same attention in the literature as subject has. Where there is a clearly monotransitive verb such as kick, the criteria for identifying the grammatical relation may converge. However, the term object is also used to refer to phenomena that do not subsume all, or even most, of the recognized properties of the canonical object. Instances of such phenomena include non-canonical objects such as the ones in the so-called double-object construction i.e. the indirect object and the direct object as in (He bought his dog a new collar). In this paper, it is demonstrated how criteria of identifying the grammatical relation object that are found in the theoretical and typological literature can be applied to Arabic. Also, further language-specific criteria are here derived from the regularities of the canonical object in the language. The criteria established in this way are then applied to the non-canonical objects to demonstrate how far they conform to, or diverge from, the canonical object. Contrary to the claim that the direct object is more similar to the canonical object than is the indirect object, it was found that it is, in fact, the indirect object rather than the direct object that shares most of the aspects of the canonical object in monotransitive clauses.

Keywords: canonical objects, double-object constructions, cognate object constructions, non-canonical objects

Procedia PDF Downloads 235

Authors: Guram Adamashvili

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Surface plasmon polariton is a surface optical wave which undergoes a strong enhancement and spatial confinement of its wave amplitude near an interface of two-dimensional layered structures. Phosphorene (single-layer black phosphorus) and other two-dimensional anisotropic phosphorene-like materials are recognized as promising materials for potential future applications of surface plasmon polariton. A theory of an optical breather of self-induced transparency for surface plasmon polariton propagating in monolayer or few-layer phosphorene is developed. A theory of an optical soliton of self-induced transparency for surface plasmon polariton propagating in monolayer or few-layer phosphorene have been investigated earlier Starting from the optical nonlinear wave equation for surface TM-modes interacting with a two-dimensional layer of atomic systems or semiconductor quantum dots and a phosphorene monolayer (or other two-dimensional anisotropic material), we have obtained the evolution equations for the electric field of the breather. In this case, one finds that the evolution of these pulses become described by the damped Bloch-Maxwell equations. For surface plasmon polariton fields, breathers are found to occur. Explicit relations of the dependence of breathers on the local media, phosphorene anisotropic conductivity, transition layer properties and transverse structures of the SPP, are obtained and will be given. It is shown that the phosphorene conductivity reduces exponentially the amplitude of the surface breather of SIT in the process of propagation. The direction of propagation corresponding to the maximum and minimum damping of the amplitude are assigned along the armchair and zigzag directions of black phosphorus nano-film, respectively. The most rapid damping of the intensity occurs when the polarization of breather is along the armchair direction.

Keywords: breathers, nonlinear waves, solitons, surface plasmon polaritons

Procedia PDF Downloads 152

Authors: Rahul Jarariya

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The textile industry uses various types of dyes and discharges a lot of highly coloured wastewater. It impacts the environment like allergic reaction, respiratory, skin problems, irritation to a mucous membrane, the upper respiratory tract has to the fore, Intoxicated dye discharges 40 to 50,000 tons with great concern. Spinel ferrites gained a lot of attention due to their wide application area from biomedical to wastewater treatment. Generally, spinel ferrite is known as M-Fe2O4. Spinel type nanoparticles possess high suspension stability. The synthesis method of Microwave solution combustion (MC) method is effective for nanoscale materials, including oxides, metals, alloys, and sulfides, works as fast and energy-efficient during the process. The review focuses on controlling, nanostructure and doping. The influence of the fuel concentration and the post-treatment temperature on the structural and magnetic properties. The effects of amounts of fuel and phase changes, particle size and shape, and magnetic properties can be characterized by various techniques. Urea is the most commonly used fuel. Ethanol or n-butanol is apt for removing impurities. As a result of the materials gives fine purity. Photocatalysis phenomena act with catalyst dosage to degrade dye from wastewater. Visible light responsive produces a large amount of hydroxyl (•OH) radical made the degradation efficiency of Rh21 type dye. It develops a narrow bandgap to make it suitable for enhanced photocatalytic activity.

Keywords: microwave solution combustion method, normal spinel, doped spinels, magnetic property, Rb21

Procedia PDF Downloads 190

Authors: C. Salis, D. Zedda, M. F. Wilson

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The IDEA project was conceived for teachers who are interested in enhancing their capacity to effectively implement the use of specific technologies in their teaching practice. Participating teachers are coached and supported as they explore technologies applied to the educational context. They access tools such as the technological platform developed by our team. Among the platform functionalities, teachers access an instructional systems design (ISD) tool (learning designer) that was adapted to the needs of our project. The tool is accessible from computers or mobile devices and used in association with other technologies to create new, meaningful learning environments. The objective of an instructional systems design is to guarantee the quality and effectiveness of education and to enhance learning. This goal involves both teachers who want to become more efficient in transferring knowledge or skills and students as the final recipient of their teaching. The use of Blooms’s taxonomy enables teachers to classify the learning objectives into levels of complexity and specificity, thus making it possible to highlight the kind of knowledge teachers would like their students to reach. The fact that the instructional design features can be visualized through the IDEA platform is a guarantee for those who are looking for specific educational materials to be used in their lessons. Despite the benefits offered, a number of teachers are reluctant to use ISD because the preparatory work of having to thoroughly analyze the teaching/learning objectives, the planning of learning material, assessment activities, etc., is long and felt to be time-consuming. This drawback is minimized using a learning designer, as the tool facilitates to reuse of the didactic contents having a clear view of the processes of analysis, planning, and production of educational or testing materials uploaded on our platform. In this paper, we shall present the feedback of the teachers who used our tool in their didactic.

Keywords: educational benefits, educational quality, educational technology, ISD tool

Procedia PDF Downloads 192

Authors: Buse T. Aydın, Enver Ozdemir

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In this study, a double layer authentication scheme between the aircraft and the Air Traffic Control (ATC) tower is designed to prevent any unauthorized aircraft from introducing themselves as friends. The method is a combination of classical cryptographic methods and new generation physical layers. The first layer has employed the embedded key of the aircraft. The embedded key is assumed to installed during the construction of the utility. The other layer is a physical attribute (flight path, distance, etc.) between the aircraft and the ATC tower. We create a mathematical model so that two layers’ information is employed and an aircraft is authenticated as a friend or foe according to the accuracy of the results of the model. The results of the aircraft are compared with the results of the ATC tower and if the values found by the aircraft and ATC tower match within a certain error margin, we mark the aircraft as a friend. In this method, even if embedded key is captured by the enemy aircraft, without the information of the second layer, the enemy can easily be determined. Overall, in this work, we present a more reliable system by adding a physical layer in the authentication process.

Keywords: ADS-B, communication with physical layer security, cryptography, identification friend or foe

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Authors: Khaled Al-Badani, James Ren, Lisa Li, David Allanson

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Droplet formation is an important process in many engineering systems and manufacturing procedures, which includes welding, biotechnologies, 3D printing, biochemical, biomedical fields and many more. The volume and the characteristics of droplet formation are generally depended on various material properties, microfluidics and fluid mechanics considerations. Hence, a detailed investigation of this process, with the aid of numerical computational tools, are essential for future design optimization and process controls of many engineering systems. This will also improve the understanding of changes in the properties and the structures of materials, during the formation of the droplet, which is important for new material developments to achieve different functions, pending the requirements of the application. For example, the shape of the formed droplet is critical for the function of some final products, such as the welding nugget during Capacitor Discharge Welding process, or PLA 3D printing, etc. Although, most academic journals on droplet formation, focused on issued with material transfer rate, surface tension and residual stresses, the general emphasis on the characteristics of droplet shape has been overlooked. The proposed work for this project will examine theoretical methodologies, experimental techniques, and numerical modelling, using ANSYS FLUENT, to critically analyse and highlight optimization methods regarding the formation of pendant droplet. The project will also compare results from published data with experimental and numerical work, concerning the effects of key material parameters on the droplet shape. These effects include changes in heating/cooling rates, solidification/melting progression and separation/break-up times. From these tests, a set of objectives is prepared, with an intention of improving quality, stability and productivity in modelling metal welding and 3D printing.

Keywords: computer modelling, droplet formation, material distortion, materials forming, welding

Procedia PDF Downloads 289

Authors: Faroojan Khajeek Sisak Siakian, Aayda Dikran Abdulahad

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The Peris Mountain is one of the main mountains in the Iraqi Kurdistan Region, it forms one of the long anticlines trending almost East – West. The exposed formations on the top of the mountain are Bekhme, and Shiranish, with carbonate rocks of different types and thicknesses. We selected the site for sampling to be relevant for a quarry taking into consideration the thickness of the exposed rocks, no overburden, favorable quarrying faces, hardness of the rocks, bedding nature, good extension of the outcrops, and a favorable place for construction of a cement plant. We sampled the exposed rocks on the top of the mountain where a road crosses the mountain, and a total of 15 samples were collected. The distance between sampling intervals was 5 m, and each sample was collected to represent the sampling interval. The samples were subjected to X-ray fluorescence spectroscopy (XRF) to indicate the main oxides percentages in each sample. The acquired results showed the studied rocks can be used in the cement industry.

Keywords: limestone, quarry, CaO, MgO, overburden

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Authors: Eugene Stepanov, Arcady Ponosov

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To model gene regulatory networks one uses ordinary differential equations with switching nonlinearities, where the initial value problem is known to be well-posed if the trajectories cross the discontinuities transversally. Otherwise, the initial value problem is usually ill-posed, which lead to theoretical and numerical complications. In the presentation, it is proposed to apply the theory of hybrid dynamical systems, rather than switched ones, to regularize the problem. 'Hybridization' of the switched system means that one attaches a dynamic discrete component ('automaton'), which follows the trajectories of the original system and governs its dynamics at the points of ill-posedness of the initial value problem making it well-posed. The construction of the automaton is based on the classification of the attractors of the specially designed adjoint dynamical system. Several examples are provided in the presentation, which support the suggested analysis. The method can also be of interest in other applied fields, where differential equations contain switchings, e.g. in neural field models.

Keywords: hybrid dynamical systems, ill-posed problems, singular perturbation analysis, switching nonlinearities

Procedia PDF Downloads 191

Authors: Ibrahim Naeimifar, Omid Naeemifar

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Evaluation of the excavation-induced ground movements is an important design aspect of support systems in urban areas. Geological and geotechnical conditions of an excavation area have significant effects on excavation-induced ground movements and the related damage. This paper is aimed at studying the performance of excavation walls supported by nails in jointed rock medium. The performance of nailed walls is investigated based on evaluating the excavation-induced ground movements. For this purpose, a set of calibrated 2D finite element models is developed by taking into account the nail-rock-structure interactions, the anisotropic properties of jointed rock, and the staged construction process. The results of this paper highlight effects of different parameters such as joint inclinations, the anisotropy of rocks and nail inclinations on deformation parameters of excavation wall supported by nails.

Keywords: finite element, jointed rock, nailing, performance

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Authors: Ashkan Shafee, Masoud Ghodrati, Ahmad Fahimifar

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Pervious concrete combines considerable permeability with adequate strength, which makes it very beneficial in pavement construction and also in ground improvement projects. In this paper, a single pervious concrete pile subjected to vertical and lateral loading is analysed using a verified three dimensional finite element code. A parametric study was carried out in order to investigate load bearing capacity of a single unreinforced pervious concrete pile in saturated soft soil and also gain insight into the failure mechanism of this rather new soil improvement technique. The results show that concrete damaged plasticity constitutive model can perfectly simulate the highly brittle nature of the pervious concrete material and considering the computed vertical and horizontal load bearing capacities, some suggestions have been made for ground improvement projects.

Keywords: concrete damaged plasticity, ground improvement, load-bearing capacity, pervious concrete pile

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Authors: Byeong-Sam Kim, Kyeongwoo Park

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In this study, induced structural optimization is performed to compare the trade-off between wing weight and induced drag for wing panel extensions, construction of wing panel and winglets. The aerostructural optimization problem consists of parameters with strength condition, and two maneuver conditions using residual stresses in panel production. The results of kinematic motion analysis presented a homogenization based theory for 3D beams and 3D shells for wing panel. This theory uses a kinematic description of the beam based on normalized displacement moments. The displacement of the wing is a significant design consideration as large deflections lead to large stresses and increased fatigue of components cause residual stresses. The stresses in the wing panel are small compared to the yield stress of aluminum alloy. This study describes the implementation of a large wing panel, aerostructural analysis and structural parameters optimization framework that couples a three-dimensional panel method.

Keywords: wing panel, aerostructural optimization, FEM, structural analysis

Procedia PDF Downloads 596

Authors: Lewis J. Woollin, Robert I. Davidson, Paul Watson, Philip J. Hyde

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Introduction: In-vitro testing of arthroplasty materials is of paramount importance when ensuring that they can withstand the performance requirements encountered in-vivo. One common machine used for in-vitro testing is a pin-on-plate tribometer, an early stage screening device that generates data on the wear characteristics of arthroplasty bearing materials. These devices test vertically loaded rotating cylindrical pins acting against reciprocating plates, representing the bearing surfaces. In this study, a pin-on-plate machine has been developed that provides several improvements over current technology, thereby progressing arthroplasty bearing research. Historically, pin-on-plate tribometers have been used to investigate the performance of arthroplasty bearing materials under conditions commonly encountered during a standard gait cycle; nominal operating pressures of 2-6 MPa and an operating frequency of 1 Hz are typical. There has been increased interest in using pin-on-plate machines to test more representative in-vivo conditions, due to the drive to test 'beyond compliance', as well as their testing speed and economic advantages over hip simulators. Current pin-on-plate machines do not accommodate the increased performance requirements associated with more extreme kinematic conditions, therefore a next-generation pin-on-plate tribometer has been developed to bridge the gap between current technology and future research requirements. Methodology: The design was driven by several physiologically relevant requirements. Firstly, an increased loading capacity was essential to replicate the peak pressures that occur in the natural hip joint during running and chair-rising, as well as increasing the understanding of wear rates in obese patients. Secondly, the introduction of mid-cycle load variation was of paramount importance, as this allows for an approximation of the loads present in a gait cycle to be applied and to test the fatigue properties of materials. Finally, the rig must be validated against previous-generation pin-on-plate and arthroplasty wear data. Results: The resulting machine is a twelve station device that is split into three sets of four stations, providing an increased testing capacity compared to most current pin-on-plate tribometers. The loading of the pins is generated using a pneumatic system, which can produce contact pressures of up to 201 MPa on a 3.2 mm² round pin face. This greatly exceeds currently achievable contact pressures in literature and opens new research avenues such as testing rim wear of mal-positioned hip implants. Additionally, the contact pressure of each set can be changed independently of the others, allowing multiple loading conditions to be tested simultaneously. Using pneumatics also allows the applied pressure to be switched ON/OFF mid-cycle, another feature not currently reported elsewhere, which allows for investigation into intermittent loading and material fatigue. The device is currently undergoing a series of validation tests using Ultra-High-Molecular-Weight-Polyethylene pins and 316L Stainless Steel Plates (polished to a Ra < 0.05 µm). The operating pressures will be between 2-6 MPa, operating at 1 Hz, allowing for validation of the machine against results reported previously in the literature. The successful production of this next-generation pin-on-plate tribometer will, following its validation, unlock multiple previously unavailable research avenues.

Keywords: arthroplasty, mechanical design, pin-on-plate, total joint replacement, wear testing

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Authors: Mohammed Aljoma

Abstract:

In this paper, a developed prototype for the scheduling of repetitive activities in height-rise buildings was presented. The activities that describe the behavior of the most of activities in multi-storey buildings are scheduled using the developed approach. The prototype combines three methods to attain the optimized planning. The methods include Critical Path Method (CPM), Gantt and Line of Balance (LOB). The developed prototype; POTER is used to schedule repetitive and non-repetitive activities with respect to all constraints that can be automatically generated using a generic database. The prototype uses the method of genetic algorithms for optimizing the planning process. As a result, this approach enables contracting organizations to evaluate various planning solutions that are calculated, tested and classified by POTER to attain an optimal time-cost equilibrium according to their own criteria of time or coast.

Keywords: planning scheduling, genetic algorithms, repetitive activity, construction management, planning, scheduling, risk management, project duration

Procedia PDF Downloads 311

Authors: Peyman Amini Motlagh, Ali Pak

Abstract:

Seismic retrofitting of important structures is essential in seismological active zones. The importance is doubled when it comes to some buildings like schools, hospitals, bridges etc. because they are required to continue their serviceability even after a major earthquake. Generally, seismic retrofitting codes have paid little attention to retrofitting of foundations due to its construction complexity. In this paper different methods for seismic retrofitting of tall buildings’ foundations will be discussed and evaluated. Foundations are considered in three different categories. First, foundations those are in danger of liquefaction of their underlying soil. Second, foundations located on slopes in seismological active regions. Third, foundations designed according to former design codes and may show structural defects under earthquake loads. After describing different methods used in different countries for retrofitting of the existing foundations in seismological active regions, comprehensive comparison between these methods with regard to the above mentioned categories is carried out. This paper gives some guidelines to choose the best method for seismic retrofitting of tall buildings’ foundations in retrofitting projects.

Keywords: existing foundation, landslide, liquefaction, seismic retrofitting

Procedia PDF Downloads 395

Authors: Jana Stepanovska, Roman Matejka, Jozef Rosina, Marta Vandrovcova, Lucie Bacakova

Abstract:

The aim of this study was to develop a system for mechanical and also electrical stimulation controlling in vitro osteogenesis under conditions more similar to the in vivo bone microenvironment than traditional static cultivation, which would achieve good adhesion, growth and other specific behaviors of osteogenic cells in cultures. An engineered culture system for mechanical stimulation of the mesenchymal stem cells on the charged surface was designed. The bioreactor allows efficient mechanical loading inducing an electrical response and perfusion of the culture chamber with seeded cells. The mesenchymal stem cells were seeded to specific charged materials, like polarized hydroxyapatite (Hap) or other materials with piezoelectric and ferroelectric features, to create electrical potentials for stimulating of the cells. The material of the matrix was TiNb alloy designed for these purposes, and it was covered by BaTiO3 film, like a kind of piezoelectric material. The process of mechanical stimulation inducing electrical response is controlled by measuring electrical potential in the chamber. It was performed a series of experiments, where the cells were seeded, perfused and stimulated up to 48 hours under different conditions, especially pressure and perfusion. The analysis of the proteins expression was done, which demonstrated the effective mechanical and electrical stimulation. The experiments demonstrated effective stimulation of the cells in comparison with the static culture. This work was supported by the Ministry of Health, grant No. 15-29153A and the Grant Agency of the Czech Republic grant No. GA15-01558S.

Keywords: charged surface, dynamic cultivation, electrical stimulation, ferroelectric layers, mechanical stimulation, piezoelectric layers

Procedia PDF Downloads 304

Authors: Vanessa Do, Lauren Smith, Leslie Carver

Abstract:

It is widely known that individuals with autism spectrum disorder (ASD) may exhibit sensitivity to stimuli. Even at a young age, they tend to display stimuli-related discomfort in their behavior during play. Play serves a crucial role in a child’s early years as it helps support healthy brain development, socio-emotional skills, and adaptation to their environment There is research dedicated to studying infant preferences for toys, especially in regard to: gender preferences, the advantages of promoting play, and the caregiver’s role in their child’s play routines. However, there is a disproportionate amount of literature examining how play patterns may differ in children with sensory sensitivity, such as children diagnosed with ASD. Prior literature has studied and found supporting evidence that individuals with ASD have deficits in social communication and have increased presence of repetitive behaviors and/or restricted interests, which also display in early childhood play patterns. This study aims to examine potential differences in toy preference between infants with (FH+) and without (FH-) a familial history of ASD ages 6. 9, and 12 months old. More specifically, this study will address the question, “do FH+ infants tend to play more with toys that require less social engagement compared to FH- infants?” Infants and their caregivers were recruited and asked to engage in a free-play session in their homes that lasted approximately 5 minutes. The sessions were recorded and later coded offline for engagement behaviors categorized by toy; each toy that the infants interacted with was coded as belonging to one of 6 categories: sensory (designed to stimulate one or more senses such as light-up toys or musical toys) , construction (e.g., building blocks, rubber suction cups), vehicles (e.g., toy cars), instructional (require steps to accomplish a goal such as flip phones or books), imaginative (e.g., dolls, stuffed animals), and miscellaneous (toys that do not fit into these categories). Toy engagement was defined as the infant looking and touching the toy (ILT) or looking at the toy while their caregiver was holding it (IL-CT). Results reported include/will include the proportion of time the infant was actively engaged with the toy out of the total usable video time per subject — distractions observed during the session were excluded from analysis. Data collection is still ongoing; however, the prediction is that FH+ infants will have higher engagement with sensory and construction toys as they require the least amount of social effort. Furthermore, FH+ infants will have the least engagement with the imaginative toys as prior literature has supported the claim that individuals with ASD have a decreased likelihood to engage in play that requires pretend play and other social skills. Looking at what toys are more or less engaging to FH+ infants is important as it provides significant contributions to their healthy cognitive, social, and emotional development. As play is one of the first ways for a child to understand the complexities of the larger world, the findings of this study may help guide further research into encouraging play with toys that are more engaging and sensory-sensitive for children with ASD.

Keywords: autism engagement, children’s play, early development, free-play, infants, toy

Procedia PDF Downloads 223