Search results for: structural dynamics

Authors: Henry Munoz, Muhammad Mohsan, Takashi Kiyota

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Strength and deformability characteristics of a liquefiable sand deposit including the development of earthquake-induced shear stress and shear strain as well as soil softening via the progressive degradation of shear modulus were studied via shaking table experiments. To do so, a model of a liquefiable sand deposit was constructed and densely instrumented where accelerations, pressures, and displacements at different locations were continuously monitored. Furthermore, the confinement effects on the strength and deformation characteristics of the liquefiable sand deposit due to an external surcharge by placing a heavy concrete slab (i.e. the model of an actual structural rigid pavement) on the ground surface were examined. The results indicate that as the number of seismic-loading cycles increases, the sand deposit softens progressively as large shear strains take place in different sand elements. Liquefaction state is reached after the combined effects of the progressive degradation of the initial shear modulus associated with the continuous decrease in the mean principal stress, and the buildup of the excess of pore pressure takes place in the sand deposit. Finally, the confinement effects given by a concrete slab placed on the surface of the sand deposit resulted in a favorable increasing in the initial shear modulus, an increase in the mean principal stress and a decrease in the softening rate (i.e. the decreasing rate in shear modulus) of the sand, thus making the onset of liquefaction to take place at a later stage. This is, only after the sand deposit having a concrete slab experienced a higher number of seismic loading cycles liquefaction took place, in contrast to an ordinary sand deposit having no concrete slab.

Keywords: liquefaction, shear modulus degradation, shaking table, earthquake

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Authors: M. Hanif Irsyada, Rifaldy, Arif Lutfi Namury, Syahreza S. Angkasa, Khalid Rizky, Ricky Aryanto, M. Alfiyan Bagus, Excobar Arman, Fahri Septianto, Firman Najib Wibisana

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Galunggung Mountain is an active volcano in Indonesia, precisely on the island of Java. This area is included in the Sunda Sunda arc formed by the tendency of the Australian oceanic plate to Eurasian continental plate. This research was conducted to determine the characteristics and document the mineralogical composition of the Galunggung eruption of the second phase 1982-1983. In fragment samples, petrographic analysis is carried out under a qualitative and quantitative polarizing microscope. This sample was obtained from the second phase eruption in the Cibanjanj formation. Based on the analysis results obtained filter texture characteristics, olivine parallel growth, lamellar structure, glass inclusion, plagioclase zonation and obtained special texture in the gabbroic cummulate. The mineral composition consists of phenocryst plagioclase (41vol%), pyroxene (26vol%), olivin (4vol%) and mineral opaque (29vol%). Microlite minerals consist of plagioclase (31.95vol%), pyroxene (12.09vol%), opaque minerals (55.96vol%). This research is expected to be developed by further researchers to be able to explain in more detail related to Galunggung mountain with 3 phases of eruption that are so intense. Also, it is expected to explain the structural characteristics and mineralogical composition that can be used to determine the origin of all the results of the Galunggung eruption 1982-1983.

Keywords: Galunggung eruption, mineralogical composition, texture characterization, gabbroic cumulate

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Authors: Thuy Phuong Nhat Tran, Ashutosh Thakur, Toshiaki Taniike

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Recently, covalently linked graphene oxide frameworks (GOFs) have attracted considerable attention in gas absorbance and water purification as well-defined microporous materials. In spite of their potential advantages such as a controllable pore dimension, adjustable hydrophobicity, and structural stability, these materials have been scarcely employed in heterogeneous catalysis. Here we demonstrate a novel and facile method to synthesize Pd nanoparticles (NPs) confined in a GOF (Pd@GOF). The GOF with uniform interlayer space was obtained by the intercalation of diboronic acid between graphene oxide layers. It was found that Pd NPs were generated inside the graphitic gallery spaces of the GOF, and thus, formed Pd NPs were well-dispersed with a narrow particle size distribution. The synthesized Pd@GOF emerged as an efficient nanocatalyst based on its superior performance (product yield and recyclability) toward Suzuki-Miyaura cross-coupling reaction in both polar and apolar solvents, which has been hardly observed for previously reported graphene-based Pd nanocatalysts. Furthermore, the rational comparison of the catalytic performance between two kinds of Pd@GOF (Pd NPs encapsulated in a diboronic ester-intercalated GOF and in a monoboronic ester-intercalated GOF) firmly confirmed the essential role of a rigid framework design in the stabilization of Pd NPs. Based on these results, the covalently assembled GOF was proposed as a promising scaffold for hosting noble metal NPs to construct desired metal@GOF nanocatalysts with improved activity and durability.

Keywords: graphene oxide framework, palladium nanocatalyst, pore confinement, Suzuki-Miyaura cross-coupling reaction

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Authors: Sina Modares Ahmadi, Mohamad Reza Ghazavi, Mandana Sheikhzad

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Squeeze film damper systems (SFD) are often used in machines with high rotational speed to reduce non-periodic behavior by creating external damping. These types of systems are frequently used in aircraft gas turbine engines. There are some structural parameters which are of great importance in designing these kinds of systems, such as oil film thickness, C, and outer race mass, mo. Moreover, there is a crucial parameter associated with manufacturing process, under the title of waviness. Geometric imperfections are often called waviness if its wavelength is much longer than Hertzian contact width which is a considerable source of vibration in ball bearings. In this paper, a system of a flexible rotor and two ball bearings with floating ring squeeze film dampers and consideration of waviness has been modeled and solved by a numerical integration method, namely Runge-Kutta method to investigate the dynamic response of the system. The results show that by increasing the number of wave lobes, which is due to inappropriate manufacturing, non- periodic and chaotic behavior increases. This result reveals the importance of manufacturing accuracy. Moreover, as long as C< 1.5×10-4 m, by increasing the oil film thickness, unwanted vibrations and non-periodic behavior of the system have been reduced, On the other hand, when C>1.5×10-4 m, increasing the outer oil film thickness results in the increasing chaotic and non-periodic responses. This result shows that although the presence of oil film results in reduction the non-periodic and chaotic behaviors, but the oil film has an optimal thickness. In addition, with increasing mo, the disc displacement amplitude increases. This result reveals the importance of utilizing light materials in manufacturing the squeeze film dampers.

Keywords: squeeze-film damper, waviness, ball bearing, bifurcation

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Authors: Sijuade A. A., Oguntoye J. P., Awodoye O. O., Adedapo O. A., Wahab W. B., Okediran O. O., Omidiora E. O., Olabiyisi S. O.

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Electronic voting systems have been introduced to improve the efficiency, accuracy, and transparency of the election process in many countries around the world, including Nigeria. However, concerns have been raised about the security and integrity of these systems. One way to address these concerns is through the implementation of electronic forensic election audit systems. This study aims to evaluate voters' intention to the adoption of electronic forensic election audit systems using the Unified Theory of Acceptance and Use of Technology (UTAUT) model. In the study, the UTAUT model which is a widely used model in the field of information systems to explain the factors that influence individuals' intention to use a technology by integrating performance expectancy, effort expectancy, social influence, facilitating conditions, cost factor and privacy factor to voters’ behavioural intention was proposed. A total of 294 sample data were collected from a selected population of electorates who had at one time or the other participated in at least an electioneering process in Nigeria. The data was then analyzed statistically using Partial Least Square Structural Equation Modeling (PLS-SEM). The results obtained show that all variables have a significant effect on the electorates’ behavioral intention to adopt the development and implementation of an electronic forensic election audit system in Nigeria.

Keywords: election Audi, voters, UTAUT, performance expectancy, effort expectancy, social influence, facilitating condition social influence, facilitating conditions, cost factor, privacy factor, behavioural intention

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Authors: M. Abdoos, A. Amadeh, M. Adabi

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In recent decades, the use of titanium and its alloys due to their high mechanical properties, light weight and their corrosion resistance has increased in military and industry applications. However, the poor surface properties can limit their widely usage. Many researches were carried out to improve their surface properties. The most effective technique is based on solid-state diffusion of elements that can form intermetallic compounds with the substrate. In the present work, inter-diffusion of nickel and titanium and formation of Ni-Ti intermetallic compounds in nickel-coated Ti-6Al-4V alloy have been studied. Initially, nickel was electrodeposited on the alloy using Watts bath at a current density of 20 mA/cm2 for 1 hour. The coated specimens were then heat treated in a tubular furnace under argon atmosphere at different temperatures near Ti β-transus to maximize the diffusion rate for various durations in order to improve the surface properties of the Ti-6Al-4V alloy. The effect of temperature and time on the thickness of diffusion layer and characteristics of intermetallic phases was studied by means of scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS) and microhardness test. The results showed that a multilayer structure was formed after heat treatment: an outer layer of remaining nickel, an area of intermetallic layers with different compositions and solid solution of Ni-Ti. Three intermetallic layers was detected by EDS analysis, namely an outer layer with about 75 at.% Ni (Ni3Ti), an intermediate layer with 50 at.% Ni (NiTi) and finally an inner layer with 36 at.% Ni (NiTi2). It was also observed that the increase in time or temperature led to the formation of thicker intermetallic layers. Meanwhile, the microhardness of heat treated samples increased with formation of Ni-Ti intermetallics; however, its value depended on heat treatment parameters.

Keywords: heat treatment, microhardness, Ni coating, Ti-6Al-4V

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Authors: Xiaolin Li, Terence Turney, John Forsythe, Bryce Feltis, Paul Wright, Vinh Truong, Will Gates

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Clay-hydrogel nanocomposites have attracted great attention recently, mainly because of their enhanced mechanical properties and ease of fabrication. Moreover, the unique platelet structure of clay nanoparticles enables the incorporation of bioactive molecules, such as proteins or drugs, through ion exchange, adsorption or intercalation. This study seeks to improve the mechanical and rheological properties of a novel hydrogel system, copolymerized from a tetrapodal polyethylene glycol (PEG) thiol and a linear, triblock PEG-PPG-PEG (PPG: polypropylene glycol) α,ω-bispropynoate polymer, with the simultaneous incorporation of various amounts of Na-saturated, montmorillonite clay (MMT) platelets (av. lateral dimension = 200 nm), to form a bioactive three-dimensional network. Although the parent hydrogel has controlled swelling ability and its PEG groups have good affinity for the clay platelets, it suffers from poor mechanical stability and is currently unsuitable for potential applications. Nanocomposite hydrogels containing 4wt% MMT showed a twelve-fold enhancement in compressive strength, reaching 0.75MPa, and also a three-fold acceleration in gelation time, when compared with the parent hydrogel. Interestingly, clay nanoplatelet incorporation into the hydrogel slowed down the rate of its dehydration in air. Preliminary results showed that protein binding by the MMT varied with the nature of the protein, as horseradish peroxidase (HRP) was more strongly bound than bovine serum albumin. The HRP was no longer active when bound, presumably as a result of extensive structural refolding. Further work is being undertaken to assess protein binding behaviour within the nanocomposite hydrogel for potential diabetic wound healing applications.

Keywords: hydrogel, nanocomposite, small molecule, wound healing

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Authors: P. Abachi, T. W. Coyle, P. S. Musavi Gharavi

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By applying coating onto a structural component, the corrosion and/or wear resistance requirements of the surface can be fulfilled. Since the layer adhesion of the coating influences the mechanical integrity of the coat/substrate interface during the service time, it should be examined accurately. At the present work, the tensile bonding strength of the 316 stainless steel plasma sprayed coating on aluminum substrate was determined by using tensile adhesion test, TAT, specimen. The interfacial fracture toughness was specified using four-point bend specimen containing a saw notch and modified chevron-notched short-bar (SB) specimen. The coating microstructure and fractured specimen surface were examined by using scanning electron- and optical-microscopy. The investigation of coated surface after tensile adhesion test indicates that the failure mechanism is mostly cohesive and rarely adhesive type. The calculated value of critical strain energy release rate proposes relatively good interface status. It seems that four-point bending test offers a potentially more sensitive means for evaluation of mechanical integrity of coating/substrate interfaces than is possible with the tensile test. The fracture toughness value reported for the modified chevron-notched short-bar specimen testing cannot be taken as absolute value because its calculation is based on the minimum stress intensity coefficient value which has been suggested for the fracture toughness determination of homogeneous parts in the ASTM E1304-97 standard. 

Keywords: bonding strength, four-point bend test, interfacial fracture toughness, modified chevron-notched short-bar specimen, plasma sprayed coating, tensile adhesion test

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Authors: Gaurav Prabhudesai, Gaetan Brill

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The sun's energy source comes from a hydrogen-to-helium thermonuclear reaction, generating a temperature of about 5760 K on its outer layer. On account of this high temperature, energy is radiated by the sun, a part of which reaches the earth. This sunlight, even after losing part of its energy en-route to scattering and absorption, provides a time and space averaged solar flux of 174.7 W/m^2 striking the earth’s surface. According to one study, the solar energy striking earth’s surface in one and a half hour is more than the energy consumption that was recorded in the year 2001 from all sources combined. Thus, technology for extraction of solar energy holds much promise for solving energy crisis. Of the many technologies developed in this regard, Concentrating Solar Power (CSP) plants with central solar tower and receiver system are very impressive because of their capability to provide a renewable energy that can be stored in the form of heat. One design of central receiver towers is an open cavity where sunlight is concentrated into by using mirrors (also called heliostats). This concentrated solar flux produces high temperature inside the cavity which can be utilized in an energy conversion process. The amount of energy captured is reduced by losses occurring at the cavity through all three modes viz., radiation to the atmosphere, conduction to the adjoining structure and convection. This study investigates the natural convection losses to the environment from the receiver. Computational fluid dynamics were used to simulate the fluid flow and heat transfer of the receiver; since no analytical solution can be obtained and no empirical correlations exist for the given geometry. The results provide guide lines for predicting natural convection losses for hexagonal and circular shaped open cavities. Additionally, correlations are given for various inclination angles and aspect ratios. These results provide methods to minimize natural convection through careful design of receiver geometry and modification of the inclination angle, and aspect ratio of the cavity.

Keywords: concentrated solar power (CSP), central receivers, natural convection, CFD, open cavities

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Authors: Mona K. Fehling, Jakob Unger, Dietmar J. Hecker, Bernhard Schick, Joerg Lohscheller

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Voice disorders origin from disturbances of the vibration patterns of the two vocal folds located within the human larynx. Consequently, the visual examination of vocal fold vibrations is an integral part within the clinical diagnostic process. For an objective analysis of the vocal fold vibration patterns, the two-dimensional vocal fold dynamics are captured during sustained phonation using an endoscopic high-speed camera. In this work, we present an approach allowing a fully automatic analysis of the high-speed video data including a computerized classification of healthy and pathological voices. The approach bases on a wavelet-based analysis of so-called phonovibrograms (PVG), which are extracted from the high-speed videos and comprise the entire two-dimensional vibration pattern of each vocal fold individually. Using a principal component analysis (PCA) strategy a low-dimensional feature set is computed from each phonovibrogram. From the PCA-space clinically relevant measures can be derived that quantify objectively vibration abnormalities. In the first part of the work it will be shown that, using a machine learning approach, the derived measures are suitable to distinguish automatically between healthy and pathological voices. Within the approach the formation of the PCA-space and consequently the extracted quantitative measures depend on the clinical data, which were used to compute the principle components. Therefore, in the second part of the work we proposed a strategy to achieve a normalization of the PCA-space by registering the PCA-space to a coordinate system using a set of synthetically generated vibration patterns. The results show that owing to the normalization step potential ambiguousness of the parameter space can be eliminated. The normalization further allows a direct comparison of research results, which bases on PCA-spaces obtained from different clinical subjects.

Keywords: Wavelet-based analysis, Multiscale product, normalization, computer assisted classification, high-speed laryngoscopy, vocal fold analysis, phonovibrogram

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Authors: Savvas Varitis, Panagiotis Kavouras, George Vourlias, Eleni Pavlidou, Theodoros Karakostas, Philomela Komninou

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A chromium-loaded ash originating from incineration of tannery sludge under anoxic conditions was mixed with low grade soda-lime glass powder coming from commercial glass bottles. The relative weight proportions of ash over glass powder tested were 30/70, 40/60 and 50/50. The solid mixtures, formed in green state compacts, were sintered at the temperature range of 800oC up to 1200oC. The resulting products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDXS) and micro-indentation. The above methods were employed to characterize the various phases, microstructure and hardness of the produced materials. Thermal treatment at 800oC and 1000oC produced opaque ceramic products composed of a variety of chromium-containing and chromium-free crystalline phases. Thermal treatment at 1200oC gave rise to composite products, where only chromium-containing crystalline phases were detected. Hardness results suggest that specific products are serious candidates for structural applications. Acknowledgement: This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: THALES “WasteVal”: Reinforcement of the interdisciplinary and/or inter-institutional research and innovation.

Keywords: chromium-rich tannery residues, glass-ceramic materials, mechanical properties, microstructure

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Authors: Percy Galvez, Anatoly Petukhin, Paul Somerville, Ken Miyakoshi, Kojiro Irikura, Daniel Peter

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Physics-based dynamic rupture modelling is necessary for estimating parameters such as rupture velocity and slip rate function that are important for ground motion simulation, but poorly resolved by observations, e.g. by seismic source inversion. In order to generate a large number of physically self-consistent rupture models, whose rupture process is consistent with the spatio-temporal heterogeneity of past earthquakes, we use multicycle simulations under the heterogeneous rate-and-state (RS) friction law for a 45deg dip-slip fault. We performed a parametrization study by fully dynamic rupture modeling, and then, a set of spontaneous source models was generated in a large magnitude range (Mw > 7.0). In order to validate rupture models, we compare the source scaling relations vs. seismic moment Mo for the modeled rupture area S, as well as average slip Dave and the slip asperity area Sa, with similar scaling relations from the source inversions. Ground motions were also computed from our models. Their peak ground velocities (PGV) agree well with the GMPE values. We obtained good agreement of the permanent surface offset values with empirical relations. From the heterogeneous rupture models, we analyzed parameters, which are critical for ground motion simulations, i.e. distributions of slip, slip rate, rupture initiation points, rupture velocities, and source time functions. We studied cross-correlations between them and with the friction weakening distance Dc value, the only initial heterogeneity parameter in our modeling. The main findings are: (1) high slip-rate areas coincide with or are located on an outer edge of the large slip areas, (2) ruptures have a tendency to initiate in small Dc areas, and (3) high slip-rate areas correlate with areas of small Dc, large rupture velocity and short rise-time.

Keywords: earthquake dynamics, strong ground motion prediction, seismic engineering, source characterization

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Authors: Justine Cyril E. Nunag, Nestor B. Sabado Jr., Jienne Chester M. Tolosa

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Concrete has high compressive strength but a low-tension strength. The small tensile strength of concrete is regarded as its primary weakness, which is why it is typically reinforced with steel, a material that is resistant to tension. Even with steel, however, cracking can occur. In strengthening concrete, only a few researchers have modified the water to be used in a concrete mix. This study aims to compare the split tensile strength of normal structural concrete to concrete prepared with magnetic water and a quick setting admixture. In this context, magnetic water is defined as tap water that has undergone a magnetic process to become magnetized water. To test the hypothesis that magnetized concrete leads to higher split tensile strength, twenty concrete specimens were made. There were five groups, each with five samples, that were differentiated by the number of cycles (0, 50, 100, and 150). The data from the Universal Testing Machine's split tensile strength were then analyzed using various statistical models and tests to determine the significant effect of magnetized water. The result showed a moderate (+0.579) but still significant degree of correlation. The researchers also discovered that using magnetic water for 50 cycles did not result in a significant increase in the concrete's split tensile strength, which influenced the analysis of variance. These results suggest that a concrete mix containing magnetic water and a quick-setting admixture alters the typical split tensile strength of normal concrete. Magnetic water has a significant impact on concrete tensile strength. The hardness property of magnetic water influenced the split tensile strength of concrete. In addition, a higher number of cycles results in a strong water magnetism. The laboratory test results show that a higher cycle translates to a higher tensile strength.

Keywords: hardness property, magnetic water, quick-setting admixture, split tensile strength, universal testing machine

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Authors: Raviteja Chintala

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Water shortage in many areas of the world have predominantly increased the demand for efficient methods involved in the production of drinking water, So purification of water invoking cost effective and efficient methods is a challenging field of research. In this regard, Reverse osmosis membrane desalination of both seawater and inland brackish water is currently being deployed in various locations around the world. In the present work an attempt is made to integrate these existing technologies with novel method, Wherein carbon nanotubes at the lab scale are prepared which further replace activated carbon tubes being used traditionally. This has proven to enhance the efficiency of the water filter, Effectively neutralising most of the organic impurities. Furthermore, This ensures the reduction in TDS. Carbon nanotubes have wide range in scope of applications such as composite reinforcements, Field emitters, Sensors, Energy storage and energy conversion devices and catalysts support phases, Because of their unusual mechanical, Electrical, Thermal and structural properties. In particular, The large specific surface area, as well as the high chemical and thermal stability, Makes carbon nanotube an attractive adsorbent in waste water treatment. Carbon nanotubes are effective in eliminating these harmful media from water as an adsorbent. In this work, Candle soot method has been incorporated for the preparation of carbon nanotubes and mixed with activated charcoal in different compositions. The effect of composition change is monitored by using TDS measuring meter. As the composition of Nano carbon increases, The TDS of the water gradually decreases. In order to enhance the life time for carbon filter, Nano tubes are provided with larger surface area.

Keywords: TDS (Total Dissolved Solids), carbon nanotubes, water, candle soot

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Authors: Merve Sagiroglu

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The earthquake-resistant steel structure design is required taking into account the behavior of beam-column connections besides the basic properties of the structure such as material and geometry. Beam-column connections play an important role in the behavior of frame systems. Taking into account the behaviour of connection in analysis and design of steel frames is important due to presenting the actual behavior of frames. So, the behavior of the connections should be well known. The most important force which transmitted by connections in the structural system is the moment. The rotational deformation is customarily expressed as a function of the moment in the connection. So, the moment-rotation curves are the best expression of behaviour of the beam-to-column connections. The designed connections form various moment-rotation curves according to the elements of connection and the shape of placement. The only way to achieve this curve is with real-scale experiments. The experiments of some connections have been carried out partially and are formed in the databank. It has been formed the models using this databank to express the behavior of connection. In this study, theoretical studies have been carried out to model a real behavior of the top and seat angles connections with angles. Two stiffeners in the top and seat angle to increase the stiffness of the connection, and two stiffeners in the beam web to prevent local buckling are used in this beam-to-column connection. Mathematical models have been performed using the database of the beam-to-column connection experiments previously by authors. Using the data of the tests, it has been aimed that analytical expressions have been developed to obtain the moment-rotation curve for the connection details whose test data are not available. The connection has been dimensioned in various shapes and the effect of the dimensions of the connection elements on the behavior has been examined.

Keywords: top and seat angle connection, stiffener, moment-rotation curves, analytical study

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Authors: Edoardo Lomi

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A problem of central interest in anthropology concerns the ethnographic displacement of modernity’s conceptual sovereignty over that of native collectives worldwide. Part of this critical project has been the association of Western modernity with a dualist, naturalist ontology. Despite its demonstrated value for comparative work, this association often comes at the cost of reproducing ideas that lack an empirical ethnographic basis. This paper proposes a way forward by bringing to bear some of the results produced by an ethnographic study of a village in Wiltshire, South England. Due to its picturesque qualities, this village has served for decades as a ready-made set for fantasy movies and a backdrop to fictional stories. These forms of mediation have in turn generated some apparent paradoxes, such as fictitious characters that affect actual material changes, films that become more real than history, and animated stories that, while requiring material grounds to unfold, inhabit a time and space in other respects distinct from that of material processes. Drawing on ongoing fieldwork and interviews with locals and tourists, this paper considers the ways villagers engage with fiction as part of their everyday lives. The resulting image is one of convergence, in the same landscape, of people and things having different ontological status. This study invites reflection on the implications of this image for diversifying our imagery of Western lifeworlds. To this end, the notion of ‘real fictions’ is put forth, connecting the ethnographic blurring of modernist distinctions–such as sign and signified, mind and matter, materiality and immateriality–with discussions on anthropology’s own reliance on fictions for critical comparative work.

Keywords: England, ethnography, landscape, modernity, mediation, ontology, post-structural theory

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Authors: Annamária Käferné Rácz, Bence Jáger, Balázs Kövesdi, László Dunai

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Due to the numerous advantages of steel corrugated web girders, its application field is growing for bridges as well as for buildings. The global stability behavior of such girders is significantly larger than those of conventional I-girders with flat web, thus the application of the structural steel material can be significantly reduced. Design codes and specifications do not provide clear and complete rules or recommendations for the determination of the lateral torsional buckling (LTB) resistance of corrugated web girders. Therefore, the authors made a thorough investigation regarding the LTB resistance of the corrugated web girders. Finite element (FE) simulations have been performed to develop new design formulas for the determination of the LTB resistance of trapezoidally corrugated web girders. FE model is developed considering geometrical and material nonlinear analysis using equivalent geometric imperfections (GMNI analysis). The equivalent geometric imperfections involve the initial geometric imperfections and residual stresses coming from rolling, welding and flame cutting. Imperfection sensitivity analysis was performed to determine the necessary magnitudes regarding only the first eigenmodes shape imperfections. By the help of the validated FE model, an extended parametric study is carried out to investigate the LTB resistance for different trapezoidal corrugation profiles. First, the critical moment of a specific girder was calculated by FE model. The critical moments from the FE calculations are compared to the previous analytical calculation proposals. Then, nonlinear analysis was carried out to determine the ultimate resistance. Due to the numerical investigations, new proposals are developed for the determination of the LTB resistance of trapezoidally corrugated web girders through a modification factor on the design method related to the conventional flat web girders.

Keywords: corrugated web, lateral torsional buckling, critical moment, FE modeling

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Authors: Saidasanov Saidazal Shokhmurodovich, Topolnickiy Orest Zinovyevich, Afaunova Olga Arturovna

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Relevance: Bilateral congenital cleft is one of the most complex forms of all clefts, which makes it difficult to choose a surgical method of treatment. During primary operations to close the hard and soft palate, there is a shortage of soft tissues and their lack during standard uranoplasty, and these factors aggravate the period of rehabilitation of patients. Materials and methods: The results of surgical treatment of children with bilateral cleft, who underwent uranoplasty using a flap from the tongue, were analyzed. The study used methods: clinical and statistical, which allowed us to solve the tasks, based on the principles of evidence-based medicine. Results and discussion: in our study, 15 patients were studied, who underwent surgical treatment in the following volume: uranoplasty using a flap from the tongue in two stages. Of these, 9 boys and 6 girls aged 2.5 to 6 years. The first stage was surgical treatment in the volume: veloplasty. The second stage was a surgical intervention in volume: uranoplasty using a flap from the tongue. In all patients, the width of the cleft ranged from 1.6-2.8 cm. All patients in this group were orthodontically prepared. Using this method, the surgeon can achieve the following results: maximum narrowing of the palatopharyngeal ring, long soft palate, complete closure of the hard palate, alveolar process, and the mucous membrane of the nasal cavity is also sutured, which creates good conditions for the next stage of osteoplastic surgery. Based on the result obtained, patients have positive results of working with a speech therapist. In all patients, the dynamics were positive without complications. Conclusions: Based on our observation, tongue flap uranoplasty is one of the effective techniques for patients with wide clefts of the hard and soft palate. The use of a flap from the tongue makes it possible to reduce the number of repeated reoperations and improve the quality of social adaptation of this group of patients, which is one of the important stages of rehabilitation. Upon completion of the stages of rehabilitation, all patients had the maximum improvement in functional, anatomical and social indicators.

Keywords: congenital cleft lips and palate, bilateral cleft, child surgery, maxillofacial surgery

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Authors: Neeta Khurana, Ritu Sharma

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This paper is an impact assessment study of the rehabilitation work done for Chhara women in the rural precincts of Ahmedabad. The Chharas constitute a denotified tribe and live in abject poverty. The women of this community are infamous absconders of law and active bootleggers of locally made liquor. As part of a psychological study with a local NGO, the authors headed a training program aimed at rehabilitating and providing these women alternate modes of employment, thereby driving them away from a life of crime. The paper centers on the idea of women entrepreneurship and women empowerment. It notes the importance of handholding in a conflict situation. Most of the research on Chharas is either focused on victimising them for state-sponsored violence or mostly makes a plea on reconditioning them in the mainstream. Going against this trend, this paper which documents the study argues that making these poor women self-dependent is a panacea for their sluggish development. The alienation caused due to the demonisation of the community has made them abandon traditional modes of employment. This has further led the community astray into making illegal country liquor causing further damage to their reputation. Women are at the centre of this vicious circle facing much repression and ostracisation. The study conducted by the PDPU team was an attempt to change this dogmatic alienation of these poor women. It was found that with consistent support and reformist approach towards law, it is possible to drive these women away from a life of penury repression and crime. The aforementioned study uses empirical tools to verify this claim. Placed at the confluence of the sociology of gender and psychology, this paper is a good way to argue that law enforcement cannot be effective without sensitisation to the ground realities of conflict. The study conducted from which the paper borrows was a scientific survey focused on markers of gender and caste realities of the Chharas. The paper mentions various dynamics involved in the training program that paved the way for the successful employment of the women. In an attempt to explain its uniqueness, the paper also has a section on comparing similar social experiments.

Keywords: employment, gender, handholding, rehabilitation

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Authors: Wedad Albalawi

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The mathematical inequalities have been the core of mathematical study and used in almost all branches of mathematics as well in various areas of science and engineering. The inequalities by Hardy, Littlewood and Polya were the first significant composition of several science. This work presents fundamental ideas, results and techniques and it has had much influence on research in various branches of analysis. Since 1934, various inequalities have been produced and studied in the literature. Furthermore, some inequalities have been formulated by some operators; in 1989, weighted Hardy inequalities have been obtained for integration operators. Then, they obtained weighted estimates for Steklov operators that were used in the solution of the Cauchy problem for the wave equation. They were improved upon in 2011 to include the boundedness of integral operators from the weighted Sobolev space to the weighted Lebesgue space. Some inequalities have been demonstrated and improved using the Hardy–Steklov operator. Recently, a lot of integral inequalities have been improved by differential operators. Hardy inequality has been one of the tools that is used to consider integrity solutions of differential equations. Then dynamic inequalities of Hardy and Coposon have been extended and improved by various integral operators. These inequalities would be interesting to apply in different fields of mathematics (functional spaces, partial differential equations, mathematical modeling). Some inequalities have been appeared involving Copson and Hardy inequalities on time scales to obtain new special version of them. A time scale is defined as a closed subset contains real numbers. Then the inequalities of time scales version have received a lot of attention and has had a major field in both pure and applied mathematics. There are many applications of dynamic equations on time scales to quantum mechanics, electrical engineering, neural networks, heat transfer, combinatorics, and population dynamics. This study focuses on double integrals to obtain new time-scale inequalities of Copson driven by Steklov operator. They will be applied in the solution of the Cauchy problem for the wave equation. The proof can be done by introducing restriction on the operator in several cases. In addition, the obtained inequalities done by using some concepts in time scale version such as time scales calculus, theorem of Fubini and the inequality of H¨older.

Keywords: time scales, inequality of Hardy, inequality of Coposon, Steklov operator

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Authors: Maryam Jabeen

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In recent times, there has been a notable surge in attention towards diverse literacy concepts such as media literacy, information literacy, and digital literacy. These concepts have garnered escalating interest, spurring the emergence of novel approaches, particularly in the aftermath of the Covid-19 crisis. However, amidst discussions of crises, the domain of crisis literacy remains largely uncharted within academic exploration. Crisis literacy, also referred to as disaster literacy, denotes an individual's aptitude to not only comprehend but also effectively apply information, enabling well-informed decision-making and adherence to instructions about disaster mitigation, preparedness, response, and recovery. This theoretical and descriptive study seeks to transcend foundational literacy concepts, underscoring the urgency for an in-depth exploration of crisis literacy and its interplay with the realm of media communication. Given the profound impact of the pandemic experience and the looming uncertainty of potential future crises, there arises a pressing need to elevate crisis literacy, or disaster literacy, towards heightened autonomy and active involvement within the spheres of critical disaster preparedness, recovery initiatives, and media communication domains. This research paper is part of my ongoing Ph.D. research study, which explores on a broader level the Encoding and decoding of media communications in relation to crisis literacy. The primary objective of this research paper is to expound upon a descriptive, theoretical research endeavor delving into this domain. The emphasis lies in highlighting the paramount significance of media communications in literacy of crisis, coupled with an accentuated focus on its role in providing information to marginalized populations amidst crises. In conclusion, this research bridges the gap in crisis literacy correlation to media communications exploration, advocating for a comprehensive understanding of its dynamics and its symbiotic relationship with media communications. It intends to foster a heightened sense of crisis literacy, particularly within marginalized communities, catalyzing proactive participation in disaster preparedness, recovery processes, and adept media interactions.

Keywords: covid-19, crisis literacy, crisis, marginalized, media and communications, pandemic, vulnerable people

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Authors: E. P. Bhowmik, R. Singh

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Certain materials casually thrown away as by-product household waste, such as used tea leaves, used coffee remnants, eggshells, peanut husks, coconut coir, unwanted paper, and pencil shavings- have scope in the hidden properties that they offer as recyclable raw ingredients. This paper aims to explore and experiment with the sustainable potential of such disposed wastes, obtained from domestic and commercial backgrounds, that could otherwise contribute to the field of interior design if mass-collected and repurposed. Research has been conducted on available recorded methods of mass-collection, storage, and processing of such materials by certain brands, designers, and researchers, as well as the various application and angles possible with regards to re-usage. A questionnaire survey was carried out to understand the willingness of the demographics for efforts of the mass collection and their openness to such unconventional materials for interiors. An experiment was also conducted where the selected waste ingredients were used to create small samples that could be used as decorative panels. Comparisons were made for properties like color, smell, texture, relative durability, and weight- and accordingly, applications were suggested. The experiment, therefore, helped to propose to recycle of the common household as a potential surface finish for floors, walls, and ceilings, and even founding material for furniture and decor accessories such as pottery and lamp shades; for non-structural application in both residential and commercial interiors. Common by-product wastes often see their ends at landfills- laymen unaware of their sustainable possibilities dispose of them. However, processing these waste materials and repurposing them by incorporating them into interiors would serve as a sustainable alternative to ethical dilemmas in the construction of interior design/architecture elements.

Keywords: interior materials, mass-collection, sustainable, waste recycle

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Authors: Sateesh Kumar Pisini, Swetha Priya Darshini, Sanjay Kumar Shukla

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This paper seeks to present a research study on sustainability in construction of retaining wall using geosynthetics. Sustainable construction is a way for the building and infrastructure industry to move towards achieving sustainable development, taking into account environmental, socioeconomic and cultural issues. Geotechnical engineering, being very resource intensive, warrants an environmental sustainability study, but a quantitative framework for assessing the sustainability of geotechnical practices, particularly at the planning and design stages, does not exist. In geotechnical projects, major economic issues to be addressed are in the design and construction of stable slopes and retaining structures within space constraints. In this paper, quantitative indicators for assessing the environmental sustainability of retaining wall with geosynthetics are compared with conventional concrete retaining wall through life cycle assessment (LCA). Geosynthetics can make a real difference in sustainable construction techniques and contribute to development in developing countries in particular. Their imaginative application can result in considerable cost savings over the use of conventional designs and materials. The acceptance of geosynthetics in reinforced retaining wall construction has been triggered by a number of factors, including aesthetics, reliability, simple construction techniques, good seismic performance, and the ability to tolerate large deformations without structural distress. Reinforced retaining wall with geosynthetics is the best cost-effective and eco-friendly solution as compared with traditional concrete retaining wall construction. This paper presents an analysis of the theme of sustainability applied to the design and construction of traditional concrete retaining wall and presenting a cost-effective and environmental solution using geosynthetics.

Keywords: sustainability, retaining wall, geosynthetics, life cycle assessment

Procedia PDF Downloads 2019

Authors: P. Acosta-Santamaría, A. Ibatá-Soto, A. López-Vásquez

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Organic compounds in wastewaters coming from textile and pharmaceutical industry generated multiple harmful effects on the environment and the human health. One of them is the methyl orange (MeO), an azoic dye considered to be a recalcitrant compound. The heterogeneous photocatalysis emerges as an alternative for treating this type of hazardous compounds, through the generation of OH radicals using radiation and a semiconductor oxide. According to the author’s knowledge, catalysts such as TiO₂ doped with metals show high efficiency in degrading MeO; however, this presents economic limitations on industrial scale. Black sand can be considered as a naturally doped catalyst because in its structure is common to find compounds such as titanium, iron and aluminum oxides, also elements such as zircon, cadmium, manganese, etc. This study reports the photocatalytic activity of the mineral black sand used as semiconductor in the discoloration of MeO by oxidation and reduction photocatalytic techniques. For this, magnetic composites from the mineral were prepared (RM, M1, M2 and NM) and their activity were tested through MeO discoloration while TiO₂ was used as reference. For the fractions, chemical, morphological and structural characterizations were performed using Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis. M2 fraction showed higher MeO discoloration (93%) in oxidation conditions at pH 2 and it could be due to the presence of ferric oxides. However, the best result to reduction process was using M1 fraction (20%) at pH 2, which contains a higher titanium percentage. In the first process, hydrogen peroxide (H₂O₂) was used as electron donor agent. According to the results, black sand mineral can be used as natural semiconductor in photocatalytic process. It could be considered as a photocatalyst precursor in such processes, due to its low cost and easy access.

Keywords: black sand mineral, methyl orange, oxidation, photocatalysis, reduction

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Authors: Richard Draper

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A supercomputer can be constructed from identical building blocks which are small parallel processors connected by a network referred to as the local network. The routers have unused ports which are used to interconnect the building blocks. These connections are referred to as the global network. The address space has a global and a local component (g, l). The conventional way to connect the building blocks is to connect (g, l) to (g’,l). If there are K blocks, this requires K global ports in each router. If a block is of size M, the result is a machine with KM routers having diameter two. To increase the size of the machine to 2K blocks, each router connects to only half of the other blocks. The result is a larger machine but also one with greater diameter. This is a crude description of how the network of the CRAY XC® is designed. In this paper, a family of interconnection networks using routers with K global and M local ports is defined. Coordinates are (c,d, p) and the global connections are (c,d,p)↔(c’,p,d) which swaps p and d. The network is denoted D3(K,M) and is called a Swapped Dragonfly. D3(K,M) has KM2 routers and has diameter three, regardless of the size of K. To produce a network of size KM2 conventionally, diameter would be an increasing function of K. The family of Swapped Dragonflies has other desirable properties: 1) D3(K,M) scales linearly in K and quadratically in M. 2) If L < K, D3(K,M) contains many copies of D3(L,M). 3) If L < M, D3(K,M) contains many copies of D3(K,L). 4) D3(K,M) can perform an all-to-all exchange in KM2+KM time which is only slightly more than the time to do a one-to-all. This paper makes several contributions. It is the first time that a swap has been used to define a linearly scalable family of networks. Structural properties of this new family of networks are thoroughly examined. A synchronizing packet header is introduced. It specifies the path to be followed and it makes it possible to define highly parallel communication algorithm on the network. Among these is an all-to-all exchange in time KM2+KM. To demonstrate the effectiveness of the swap properties of the network of the CRAY XC® and D3(K,16) are compared.

Keywords: all-to-all exchange, CRAY XC®, Dragonfly, interconnection network, packet switching, swapped network, topology

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Authors: Mara Gabrielli, Jordi Pamies Rovira

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From a theoretical and interdisciplinary approach to visual ethnography and visual anthropology, this small scale, in-depth study explores the potential of photography as a participatory ethnographic method for a deep-understanding of the socio-educational integration of young refugees and asylum-seekers in the host society as regards their daily experiences, their needs, desires, expectations, and future goals. Qualitative data is collected by the author by observing 12 young participants in the age group 12-24 years per week for 12 months. The data consists of field notes, participatory observation, in-depth interviews with professionals, and the use of visual participatory ethnographic methods. Therefore, the young participants build their stories through the implementation of two participatory photographic methods - the 'photo-diary' and the 'photo-elicitation' - that permit them to analyse and narrate their social and educational experiences from their perspectives, thus collaborating in the construction of knowledge during the different stages of the research. Preliminary findings show the high resilience and social adaptability of young refugees and asylum-seekers to achieve their goals and overcome structural and socio-cultural barriers. However, the uncertainty of their administrative situation during the asylum submission and the lack of specific resources might impact negatively on their educational pathways and the transition to the labour market. Finally, this study also highlights the benefits of participatory photographic methods in ethnographic research, which impacts positively the well-being of these young people, helps them to develop critical thinking, and it also allows them to access information more respectfully when narrating painful experiences.

Keywords: photo-diary, photo-elicitation, resilience, strategies, visual methodologies, young refugees and asylum seekers

Procedia PDF Downloads 100

Authors: Mohammed Agbali, Claudia Trillo, Yusuf Arayici, Terrence Fernando

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The wide-spread adoption of the Smart City concept has introduced a new era of computing paradigm with opportunities for city administrators and stakeholders in various sectors to re-think the concept of urbanization and development of healthy cities. With the world population rapidly becoming urban-centric especially amongst the emerging economies, social innovation will assist greatly in deploying emerging technologies to address the development challenges in core sectors of the future cities. In this context, sustainable health-care delivery and improved quality of life of the people is considered at the heart of the healthy city agenda. This paper examines the Boston innovation landscape from the perspective of smart services and innovation ecosystem for sustainable development, especially in transportation and healthcare. It investigates the policy implementation process of the Healthy City agenda and eHealth economy innovation based on the experience of Massachusetts’s City of Boston initiatives. For this purpose, three emerging areas are emphasized, namely the eHealth concept, the innovation hubs, and the emerging technologies that drive innovation. This was carried out through empirical analysis on results of public sector and industry-wide interviews/survey about Boston’s current initiatives and the enabling environment. The paper highlights few potential research directions for service integration and social innovation for deploying emerging technologies in the healthy city agenda. The study therefore suggests the need to prioritize social innovation as an overarching strategy to build sustainable Smart Cities in order to avoid technology lock-in. Finally, it concludes that the Boston example of innovation economy is unique in view of the existing platforms for innovation and proper understanding of its dynamics, which is imperative in building smart and healthy cities where quality of life of the citizenry can be improved.

Keywords: computing paradigm, emerging technologies, equitable healthcare, healthy cities, open data, smart city, social innovation

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Authors: Alireza Arab, Morteza Elsa, Amirhossein Moghanian

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In this study, experiments were carried out to achieve a promising multifunctional and modified silicate based bioactive glass (BG). The main aim of the study was investigating the effect of lithium (Li) and magnesium (Mg) substitution, on in vitro bioactivity of substituted-58S BG. Moreover, it is noteworthy to state that modified BGs were synthesized in 60SiO₂–(36-x)CaO–4P₂O₅–(x)Li₂O and 60SiO₂–(36-x)CaO–4P₂O₅–(x)MgO (where x = 0, 5, 10 mol.%) quaternary systems, by sol-gel method. Their performance was investigated through different aspects such as biocompatibility, antibacterial activity as well as their effect on alkaline phosphatase (ALP) activity, and proliferation of MC3T3 cells. The antibacterial efficiency was evaluated against methicillin-resistant Staphylococcus aureus bacteria. To do so, CaO was substituted with Li₂O and MgO up to 10 mol % in 58S-BGs and then samples were immersed in simulated body fluid up to 14 days and then, characterized by X-ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma atomic emission spectrometry, and scanning electron microscopy. Results indicated that this modification led to a retarding effect on in vitro hydroxyapatite (HA) formation due to the lower supersaturation degree for nucleation of HA compared with 58s-BG. Meanwhile, magnesium revealed further pronounced effect. The 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) and ALP analysis illustrated that substitutions of both Li₂O and MgO, up to 5 mol %, had increasing effect on biocompatibility and stimulating proliferation of the pre-osteoblast MC3T3 cells in comparison to the control specimen. Regarding to bactericidal efficiency, the substitution of either Li or Mg for Ca in the 58s BG composition led to statistically significant difference in antibacterial behaviors of substituted-BGs. Meanwhile, the sample containing 5 mol % CaO/Li₂O substitution (BG-5L) was selected as a multifunctional biomaterial in bone repair/regeneration due to the improved biocompatibility, enhanced ALP activity and antibacterial efficiency among all of the synthesized L-BGs and M-BGs.

Keywords: alkaline, alkaline earth, bioactivity, biomedical applications, sol-gel processes

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Authors: Ayan Handulle, Memory J. Tembo-Pankuku

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The social work profession utilizes Western and Eurocentric perspectives on social structures, culture, history, belief systems, and education. This affects social work practice with indigenous groups as well as other minorities who have different perspectives. Some of the challenges that characterize social work with families, especially immigrants in western countries, are a result of different world views on child-rearing practices in the global north and the global south. A shift towards cultural sensitivity and the promotion of cultural competence has been a move towards addressing some of the challenges in child welfare practice with immigrants. However, emphasis on cultural differences presents other challenges of stereotyping and discrimination, which call for the examination of current practices to fit other groups of people. In this paper, we introduce the need for emancipatory social work in child welfare practice with immigrant parents. Emancipatory social work is directed at heightening awareness of external sources of oppression and/or privilege that hold the possibility of increasing self-esteem and courage to confront structural sources of marginalization, oppression, and exclusion. This paper draws on two research projects, respectively, “Immigrant parents’ perceptions and experiences of the welfare system” and “Norwegian- Somali parents’ fears of the Norwegian Child welfare service. The first data set comprises 15 in-depth interviews with 18 nonWestern immigrant parents, representing 10 families. The second data set consists of nine months of ethnography, seven months in Oslo, and two months in Somalia among returnees from Norway. Based on these data sets, we explore how immigrant parents’ child-rearing practices might be perceived through a racialized lens.

Keywords: child welfare, immigrants, racialization, social work

Procedia PDF Downloads 46

Authors: R. Bhattu Babajee, Marie Sandrine Estelle Benoit

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The past decades have witnessed a considerable institutional shift towards Central Bank Independence across economies of the world. The motivation behind such a change is the acceptance that increased central bank autonomy has the power of alleviating inflation bias. Hence, studying whether Central Bank Independence acts as a significant factor behind the price stability in the African economies or whether this macroeconomic aim in these countries result from other economic, political or social factors is a pertinent issue. The main research objective of this paper is to assess the relationship between central bank autonomy and inflation in African economies where inflation has proved to be a serious problem. In this optic, we shall measure the degree of CBI in Africa by computing the turnover rates of central banks governors thereby studying whether decisions made by African central banks are affected by external forces. The purpose of this study is to investigate empirically the association between Central Bank Independence (CBI) and inflation for 10 African economies over a period of 17 years, from 1995 to 2012. The sample includes Botswana, Egypt, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Nigeria, South Africa, and Uganda. In contrast to empirical research, we have not been using the usual static panel model for it is associated with potential mis specification arising from the absence of dynamics. To this issue a dynamic panel data model which integrates several control variables has been used. Firstly, the analysis includes dynamic terms to explain the tenacity of inflation. Given the confirmation of inflation inertia, that is very likely in African countries there exists the need for including lagged inflation in the empirical model. Secondly, due to known reverse causality between Central Bank Independence and inflation, the system generalized method of moments (GMM) is employed. With GMM estimators, the presence of unknown forms of heteroskedasticity is admissible as well as auto correlation in the error term. Thirdly, control variables have been used to enhance the efficiency of the model. The main finding of this paper is that central bank independence is negatively associated with inflation even after including control variables.

Keywords: central bank independence, inflation, macroeconomic variables, price stability

Procedia PDF Downloads 345