Search results for: geometry of aquifers
871 Hamilton-Jacobi Treatment of Damped Motion
Authors: Khaled I. Nawafleh
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In this work, we apply the method of Hamilton-Jacobi to obtain solutions of Hamiltonian systems in classical mechanics with two certain structures: the first structure plays a central role in the theory of time-dependent Hamiltonians, whilst the second is used to treat classical Hamiltonians, including dissipation terms. It is proved that the generalization of problems from the calculus of variation methods in the nonstationary case can be obtained naturally in Hamilton-Jacobi formalism. Then, another expression of geometry of the Hamilton Jacobi equation is retrieved for Hamiltonians with time-dependent and frictional terms. Both approaches shall be applied to many physical examples.Keywords: Hamilton-Jacobi, time dependent lagrangians, dissipative systems, variational principle
Procedia PDF Downloads 165870 Particle Size Distribution Estimation of a Mixture of Regular and Irregular Sized Particles Using Acoustic Emissions
Authors: Ejay Nsugbe, Andrew Starr, Ian Jennions, Cristobal Ruiz-Carcel
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This works investigates the possibility of using Acoustic Emissions (AE) to estimate the Particle Size Distribution (PSD) of a mixture of particles that comprise of particles of different densities and geometry. The experiments carried out involved the mixture of a set of glass and polyethylene particles that ranged from 150-212 microns and 150-250 microns respectively and an experimental rig that allowed the free fall of a continuous stream of particles on a target plate which the AE sensor was placed. By using a time domain based multiple threshold method, it was observed that the PSD of the particles in the mixture could be estimated.Keywords: acoustic emissions, particle sizing, process monitoring, signal processing
Procedia PDF Downloads 343869 Thermal Analysis of a Graphite Calorimeter for the Measurement of Absorbed Dose for Therapeutic X-Ray Beam
Authors: I.J. Kim, B.C. Kim, J.H. Kim, C.-Y. Yi
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Heat transfer in a graphite calorimeter is analyzed by using the finite elements method. The calorimeter is modeled in 3D geometry. Quasi-adiabatic mode operation is realized in the simulation and the temperature rise by different sources of the ionizing radiation and electric heaters is compared, directly. The temperature distribution caused by the electric power was much different from that by the ionizing radiation because of its point-like localized heating. However, the temperature rise which was finally read by sensing thermistors agreed well to each other within 0.02 %.Keywords: graphite calorimeter, finite element analysis, heat transfer, quasi-adiabatic mode
Procedia PDF Downloads 426868 Universality and Synchronization in Complex Quadratic Networks
Authors: Anca Radulescu, Danae Evans
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The relationship between a network’s hardwiring and its emergent dynamics are central to neuroscience. We study the principles of this correspondence in a canonical setup (in which network nodes exhibit well-studied complex quadratic dynamics), then test their universality in biological networks. By extending methods from discrete dynamics, we study the effects of network connectivity on temporal patterns, encapsulating long-term behavior into the rich topology of network Mandelbrot sets. Then elements of fractal geometry can be used to predict and classify network behavior.Keywords: canonical model, complex dynamics, dynamic networks, fractals, Mandelbrot set, network connectivity
Procedia PDF Downloads 301867 Comparison for Some Elastic and Mechanical Properties of Plutonium Dioxide
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We report some elastic parameters of cubic fluorite type neptunium dioxide (NpO2) with a recent EAM type interatomic potential through geometry optimization calculations. Typical cubic elastic constants, bulk modulus, shear modulus, young modulus and other relevant elastic parameters were also calculated during research. After calculations, we have compared our results with the available theoretical data. Our results agree well with the previous theoretical findings of the considered quantities of NpO2.Keywords: NpO2, elastic properties, bulk modulus, mechanical properties
Procedia PDF Downloads 332866 Simulation 2D of Flare Steel Tubes
Authors: B. Daheche, M. T. Hannachi, H. Djebaili
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In this approach, we tried to describe the flare test tubes welded by high frequency induction HF, and its experimental application. The test is carried out ENTTPP (National company of pipe mill and processing of flat products). Usually, the final products (tube) undergo a series of destructive testing (CD) in order to see the efficiency of welding. This test performed on sections of pipe with a length defined in the notice is made under a determined effort (pressure), which depends on its share of other parameters namely mechanical (fracture resistance) and geometry (thickness tube, outside diameter), the variation of this effort is well researched and recorded.Keywords: flare, destructive testing, pressure, drafts tube, tube finished
Procedia PDF Downloads 312865 Spin Resolved Electronic Behavior of Zno Nanoribbons
Authors: Serkan Caliskan
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The aim of this study is to understand the spin-resolved properties of ZnO armchair and zigzag nanoribbons. The spin polarization can be induced by either geometry of the nanoribbons or ferromagnetic electrodes. Hence, spin-dependent behavior is revealed in these nanostructures in the absence of external magnetic field. Both electronic structure and magnetic properties of the nanoribbons are analyzed, employing first-principles calculations through Density Functional Theory. The relevant properties using the spin-dependent band structure, conductance, transmission, density of states and magnetic moment are elucidated. These results can be utilized to describe the nanoscale structures and stimulate the experimental works.Keywords: first principles, spin polarized transport, ZnO device, ZnO nanoribbons
Procedia PDF Downloads 184864 Optimization of the Aerodynamic Performances of an Unmanned Aerial Vehicle
Authors: Fares Senouci, Bachir Imine
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This document provides numerical and experimental optimization of the aerodynamic performance of a drone equipped with three types of horizontal stabilizer. To build this optimal configuration, an experimental and numerical study was conducted on three parameters: the geometry of the stabilizer (horizontal form or reverse V form), the position of the horizontal stabilizer (up or down), and the landing gear position (closed or open). The results show that up-stabilizer position with respect to the horizontal plane of the fuselage provides better aerodynamic performance, and that the landing gear increases the lift in the zone of stability, that is to say where the flow is not separated.Keywords: aerodynamics, drag, lift, turbulence model, wind tunnel
Procedia PDF Downloads 247863 Temperature Distribution Simulation of Divergent Fluid Flow with Helical Arrangement
Authors: Ehan Sabah Shukri, Wirachman Wisnoe
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Numerical study is performed to investigate the temperature distribution in an annular diffuser fitted with helical tape hub. Different pitches (Y = 20 mm, and Y = 30 mm) for the helical tape are studied with different heights (H = 20 mm, 22 mm, and 24 mm) to be compared. The geometry of the annular diffuser and the inlet condition for both hub arrangements are kept constant. The result obtains that using helical tape insert with different pitches and different heights will force the temperature to distribute in a helical direction; however the use of helical tape hub with height (H = 22 mm) for both pitches enhance the temperature distribution in a good manner.Keywords: helical tape, divergent fluid flow, temperature distribution, swirl flow, CFD
Procedia PDF Downloads 443862 An Approximation Method for Exact Boundary Controllability of Euler-Bernoulli
Authors: A. Khernane, N. Khelil, L. Djerou
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The aim of this work is to study the numerical implementation of the Hilbert uniqueness method for the exact boundary controllability of Euler-Bernoulli beam equation. This study may be difficult. This will depend on the problem under consideration (geometry, control, and dimension) and the numerical method used. Knowledge of the asymptotic behaviour of the control governing the system at time T may be useful for its calculation. This idea will be developed in this study. We have characterized as a first step the solution by a minimization principle and proposed secondly a method for its resolution to approximate the control steering the considered system to rest at time T.Keywords: boundary control, exact controllability, finite difference methods, functional optimization
Procedia PDF Downloads 340861 Numerical Study of Two Mechanical Stirring Systems for Yield Stress Fluid
Authors: Amine Benmoussa, Mebrouk Rebhi, Rahmani Lakhdar
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Mechanically agitated vessels are commonly used for various operations within a wide range process in chemical, pharmaceutical, polymer, biochemical, mineral, petroleum industries. Depending on the purpose of the operation carried out in mixer, the best choice for geometry of the tank and agitator type can vary widely. In this paper, the laminar 2D agitation flow and power consumption of viscoplastic fluids with straight and circular gate impellers in a stirring tank is studied by using computational fluid dynamics (CFD), where the velocity profile, the velocity fields and power consumption was analyzed.Keywords: CFD, mechanical stirring, power consumption, yield stress fluid
Procedia PDF Downloads 345860 Two Houses in the Arabian Desert: Assessing the Built Work of RCR Architects in the UAE
Authors: Igor Peraza Curiel, Suzanne Strum
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Today, when many foreign architects are receiving commissions in the United Arab Emirates, it is essential to analyze how their designs are influenced by the region's culture, environment, and building traditions. This study examines the approach to siting, geometry, construction methods, and material choices in two private homes for a family in Dubai, a project being constructed on adjacent sites by the acclaimed Spanish team of RCR Architects. Their third project in Dubai, the houses mark a turning point in their design approach to the desert. The Pritzker Prize-winning architects of RCR gained renown for building works deeply responsive to the history, landscape, and customs of their hometown in a volcanic area of the Catalonia region of Spain. Key formative projects and their entry to practice in UAE will be analyzed according to the concepts of place identity, the poetics of construction, and material imagination. The poetics of construction, a theoretical position with a long practical tradition, was revived by the British critic Kenneth Frampton. The idea of architecture as a constructional craft is related to the concepts of material imagination and place identity--phenomenological concerns with the creative engagement with local matter and topography that are at the very essence of RCR's way of designing, detailing, and making. Our study situates RCR within the challenges of building in the region, where western forms and means have largely replaced the ingenious responsiveness of indigenous architecture to the climate and material scarcity. The dwellings, iterations of the same steel and concrete vaulting system, highlight the conceptual framework of RCR's design approach to offer a study in contemporary critical regionalism. The Kama House evokes Bedouin tents, while the Alwah House takes the form of desert dunes in response to the temporality of the winds. Metal mesh screens designed to capture the shifting sands will complete the forms. The original research draws on interviews with the architects and unique documentation provided by them and collected by the authors during on-site visits. By examining the two houses in-depth, this paper foregrounds a series of timely questions: 1) What is the impact of the local climatic, cultural, and material conditions on their project in the UAE? 2) How does this work further their experiences in the region? 3) How has RCR adapted their construction techniques as their work expands beyond familiar settings? The investigation seeks to understand how the design methodology developed for more than 20 years and enmeshed in the regional milieu of their hometown can transform as the architects encounter unique characteristics and values in the Middle East. By focusing on the contemporary interpretation of Arabic geometry and elements, the houses reveal the role of geometry, tectonics, and material specificity in the realization from conceptual sketches to built form. In emphasizing the importance of regional responsiveness, the dynamics of international construction practice, and detailing this study highlights essential issues for professionals and students looking to practice in an increasingly global market.Keywords: material imagination, regional responsiveness, place identity, poetics of construction
Procedia PDF Downloads 129859 Error Estimation for the Reconstruction Algorithm with Fan Beam Geometry
Authors: Nirmal Yadav, Tanuja Srivastava
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Shannon theory is an exact method to recover a band limited signals from its sampled values in discrete implementation, using sinc interpolators. But sinc based results are not much satisfactory for band-limited calculations so that convolution with window function, having compact support, has been introduced. Convolution Backprojection algorithm with window function is an approximation algorithm. In this paper, the error has been calculated, arises due to this approximation nature of reconstruction algorithm. This result will be defined for fan beam projection data which is more faster than parallel beam projection.Keywords: computed tomography, convolution backprojection, radon transform, fan beam
Procedia PDF Downloads 481858 Numerical Simulation for Self-Loosening Phenomenon Analysis of Bolt Joint under Vibration
Authors: Long Kim Vu, Ban Dang Nguyen
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In this paper, the finite element method (FEM) is utilized to simulate the comprehensive process including tightening, releasing and self-loosening of a bolt joint under transverse vibration. Following to the accurate geometry of helical threads, an absolutely hexahedral meshing is implemented. The accuracy of simulation process is verified and validated by comparison with the experimental results on clamping force-vibration relationship, which shows the sufficient correlation. Further analysis with different amplitude and frequency of transverse vibration is done to determine the dominant factor inducing the failure.Keywords: bolt self-loosening, contact state, finite element method, FEM, helical thread modeling
Procedia PDF Downloads 195857 Geoelectical Resistivity Method in Aquifer Characterization at Opic Estate, Isheri-Osun River Basin, South Western Nigeria
Authors: B. R. Faleye, M. I. Titocan, M. P. Ibitola
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Investigation was carried out at Opic Estate in Isheri-Osun River Basin environment using Electrical Resistivity method to study saltwater intrusion into a fresh water aquifer system from the proximal estuarine water body. The investigation is aimed at aquifer characterisation using electrical resistivity method in order to provide the depth to which fresh water fit for both domestic and industrial consumption. The 2D Electrical Resistivity and Vertical Electrical Resistivity techniques alongside Laboratory analysis of water samples obtained from the boreholes were adopted. Three traverses were investigated using Wenner and Pole-Dipole array with multi-electrode system consisting of 84 electrodes and a spread of 581 m, 664 m and 830 m were attained on the traverses. The main lithologies represented in the study area are Sand, Clay and Clayey Sand of which Sand constitutes the aquifer in the study area. Vertical Electrical Sounding data obtained at different lateral distance on the traverses have indicated that the water in the aquifer in the subsurface is brackish. Brackish water is represented by lowelectrical resistivity value signature while fresh water is characterized by relatively high electrical resistivity and in some regionfresh water is existent at depth greater than 200 m. Results of laboratory analysis of samples showed that the pH, Salinity, Total Dissolved Solid and Conductivity indicated existence of water with poor quality, indicating that salinity, TDS and Conductivity is higher in the Northern part of the study area. The 2D electrical resistivity and Vertical Electrical Sounding methods indicate that fresh water region is at ≥200m depth. Aquifers not fit for domestic use in the study area occur downwards to about 200 m in depth. In conclusion, it is recommended that wells should be sunkbeyond 220 m for the possible procurement of portable fresh water.Keywords: 2D electrical resistivity, aquifer, brackish water, lithologies
Procedia PDF Downloads 425856 Metaphysics of the Unified Field of the Universe
Authors: Santosh Kaware, Dnyandeo Patil, Moninder Modgil, Hemant Bhoir, Debendra Behera
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The Unified Field Theory has been an area of intensive research since many decades. This paper focuses on philosophy and metaphysics of unified field theory at Planck scale - and its relationship with super string theory and Quantum Vacuum Dynamic Physics. We examined the epistemology of questions such as - (1) what is the Unified Field of universe? (2) can it actually - (a) permeate the complete universe - or (b) be localized in bound regions of the universe - or, (c) extend into the extra dimensions? - -or (d) live only in extra dimensions? (3) What should be the emergent ontological properties of Unified field? (4) How the universe is manifesting through its Quantum Vacuum energies? (5) How is the space time metric coupled to the Unified field? We present a number of ansatz - which we outline below. It is proposed that the unified field possesses consciousness as well as a memory - a recording of past history - analogous to ‘Consistent Histories’ interpretation of quantum mechanics. We proposed Planck scale geometry of Unified Field with circle like topology and having 32 energy points on its periphery which are the connected to each other by 10 dimensional meta-strings which are sources for manifestation of different fundamentals forces and particles of universe through its Quantum Vacuum energies. It is also proposed that the sub energy levels of ‘Conscious Unified Field’ are used for the process of creation, preservation and rejuvenation of the universe over a period of time by means of negentropy. These epochs can be for the complete universe, or for localized regions such as galaxies or cluster of galaxies. It is proposed that Unified field operates through geometric patterns of its Quantum Vacuum energies - manifesting as various elementary particles by giving spins to zero point energy elements. Epistemological relationship between unified field theory and super-string theories is examined. Properties of ‘consciousness’ and 'memory' cascades from universe, into macroscopic objects - and further onto the elementary particles - via a fractal pattern. Other properties of fundamental particles - such as mass, charge, spin, iso-spin also spill out of such a cascade. The manifestations of the unified field can reach into the parallel universes or the ‘multi-verse’ and essentially have an existence independent of the space-time. It is proposed that mass, length, time scales of the unified theory are less than even the Planck scale - and can be called at a level which we call that of 'Super Quantum Gravity (SQG)'.Keywords: super string theory, Planck scale geometry, negentropy, super quantum gravity
Procedia PDF Downloads 265855 Nano-Enhanced In-Situ and Field Up-Gradation of Heavy Oil
Authors: Devesh Motwani, Ranjana S. Baruah
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The prime incentive behind up gradation of heavy oil is to increase its API gravity for ease of transportation to refineries, thus expanding the market access of bitumen-based crude to the refineries. There has always been a demand for an integrated approach that aims at simplifying the upgrading scheme, making it adaptable to the production site in terms of economics, environment, and personnel safety. Recent advances in nanotechnology have facilitated the development of two lines of heavy oil upgrading processes that make use of nano-catalysts for producing upgraded oil: In Situ Upgrading and Field Upgrading. The In-Situ upgrading scheme makes use of Hot Fluid Injection (HFI) technique where heavy fractions separated from produced oil are injected into the formations to reintroduce heat into the reservoir along with suspended nano-catalysts and hydrogen. In the presence of hydrogen, catalytic exothermic hydro-processing reactions occur that produce light gases and volatile hydrocarbons which contribute to increased oil detachment from the rock resulting in enhanced recovery. In this way the process is a combination of enhanced heavy oil recovery along with up gradation that effectively handles the heat load within the reservoirs, reduces hydrocarbon waste generation and minimizes the need for diluents. By eliminating most of the residual oil, the Synthetic Crude Oil (SCO) is much easier to transport and more amenable for processing in refineries. For heavy oil reservoirs seriously impacted by the presence of aquifers, the nano-catalytic technology can still be implemented on field though with some additional investments and reduced synergies; however still significantly serving the purpose of production of transportable oil with substantial benefits with respect to both large scale upgrading, and known commercial field upgrading technologies currently on the market. The paper aims to delve deeper into the technology discussed, and the future compatibility.Keywords: upgrading, synthetic crude oil, nano-catalytic technology, compatibility
Procedia PDF Downloads 398854 Fatigue Crack Initiation of Al-Alloys: Effect of Heat Treatment Condition
Authors: M. Benachour, N. Benachour, M. Benguediab
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In this investigation an empirical study was made on fatigue crack initiation on 7075 T6 and 7075 T71 al-alloys under constant amplitude loading. At initiation stage, local strain approach at the notch was applied. Single Edge Notch Tensile specimen with semi circular notch is used. Based on experimental results, effect of mean stress, is highlights on fatigue initiation life. Results show that fatigue life initiation is affected by notch geometry and mean stress.Keywords: fatigue crack initiation, al-alloy, mean stress, heat treatment state
Procedia PDF Downloads 228853 Detailed Observations on Numerically Invariant Signatures
Authors: Reza Aghayan
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Numerically invariant signatures were introduced as a new paradigm of the invariant recognition for visual objects modulo a certain group of transformations. This paper shows that the current formulation suffers from noise and indeterminacy in the resulting joint group-signatures and applies the n-difference technique and the m-mean signature method to minimize their effects. In our experimental results of applying the proposed numerical scheme to generate joint group-invariant signatures, the sensitivity of some parameters such as regularity and mesh resolution used in the algorithm will also be examined. Finally, several interesting observations are made.Keywords: Euclidean and affine geometry, differential invariant G-signature curves, numerically invariant joint G-signatures, object recognition, noise, indeterminacy
Procedia PDF Downloads 392852 Monitoring and Management of Aquatic Macroinvertebrates for Determining the Level of Water Pollution Catchment Basin of Debed River, Armenia
Authors: Inga Badasyan
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Every year we do monitoring of water pollution of catchment basin of Debed River. Next, the Ministry of Nature Protection does modeling programme. Finely, we are managing the impact of water pollution in Debed river. Ecosystem technologies efficiency performance were estimated based on the physical, chemical, and macrobiological analyses of water on regular base between 2012 to 2015. Algae community composition was determined to assess the ecological status of Debed river, while vegetation was determined to assess biodiversity. Last time, experts werespeaking about global warming, which is having bad impact on the surface water, freshwater, etc. As, we know that global warming is caused by the current high levels of carbon dioxide in the water. Geochemical modelling is increasingly playing an important role in various areas of hydro sciences and earth sciences. Geochemical modelling of highly concentrated aqueous solutions represents an important topic in the study of many environments such as evaporation ponds, groundwater and soils in arid and semi-arid zones, costal aquifers, etc. The sampling time is important for benthic macroinvertebrates, for that reason we have chosen in the spring (abundant flow of the river, the beginning of the vegetation season) and autumn (the flow of river is scarce). The macroinvertebrates are good indicator for a chromic pollution and aquatic ecosystems. Results of our earlier investigations in the Debed river reservoirs clearly show that management problem of ecosystem reservoirs is topical. Research results can be applied to studies of monitoring water quality in the rivers and allow for rate changes and to predict possible future changes in the nature of the lake.Keywords: ecohydrological monitoring, flood risk management, global warming, aquatic macroinvertebrates
Procedia PDF Downloads 280851 3D Numerical Simulation on Annular Diffuser Temperature Distribution Enhancement by Different Twist Arrangement
Authors: Ehan Sabah Shukri, Wirachman Wisnoe
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The influence of twist arrangement on the temperature distribution in an annular diffuser fitted with twisted rectangular hub is investigated. Different pitches (Y = 120 mm, 100 mm, 80 mm, and 60 mm) for the twist arrangements are simulated to be compared. The geometry of the annular diffuser and the inlet condition for the hub arrangements are kept constant. The result reveals that using twisted rectangular hub insert with different pitches will force the temperature to distribute in a circular direction. However, temperature distribution will be enhanced with the length pitch increases.Keywords: numerical simulation, twist arrangement, annular diffuser, temperature distribution, swirl flow, pitches
Procedia PDF Downloads 405850 A Benchmark for Some Elastic and Mechanical Properties of Uranium Dioxide
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We present some elastic parameters of cubic fluorite type uranium dioxide (UO2) with a recent EAM type interatomic potential through geometry optimization calculations. Typical cubic elastic constants, bulk modulus, shear modulus, young modulus and other related elastic parameters were calculated during research. After calculations, we compared our results not only with the available theoretical data but also with previous experimental results. Our results are consistent with experiments and compare well the former theoretical results of the considered parameters of UO2.Keywords: UO2, elastic constants, bulk modulus, mechanical properties
Procedia PDF Downloads 405849 A Comparison for Some Elastic and Mechanical Properties of Neptunium Dioxide
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We report some elastic quantities of cubic fluorite type plutonium dioxide (PuO2) with a recent EAM type interatomic potential through geometry optimization calculations. Typical cubic elastic constants, bulk modulus, shear modulus, young modulus and other related elastic quantities were calculated during present research. After present calculations, we have compared our results with the existing theoretical data of literature. Our results are consistent with previous theoretical findings of the considered parameters of PuO2.Keywords: PuO2, elastic properties, bulk modulus, mechanical properties
Procedia PDF Downloads 305848 Numerical Study on the Hazards of Gravitational Forces on Cerebral Aneurysms
Authors: Hashem M. Alargha, Mohammad O. Hamdan, Waseem H. Aziz
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Aerobatic and military pilots are subjected to high gravitational forces that could cause blackout, physical injuries or death. A CFD simulation using fluid-solid interactions scheme has been conducted to investigate the gravitational effects and hazards inside cerebral aneurysms. Medical data have been used to derive the size and geometry of a simple aneurysm on a T-shaped bifurcation. The results show that gravitational force has no effect on maximum Wall Shear Stress (WSS); hence, it will not cause aneurysm initiation/formation. However, gravitational force cause causes hypertension which could contribute to aneurysm rupture.Keywords: aneurysm, cfd, wall shear stress, gravity, fluid dynamics, bifurcation artery
Procedia PDF Downloads 363847 Chebyshev Wavelets and Applications
Authors: Emanuel Guariglia
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In this paper we deal with Chebyshev wavelets. We analyze their properties computing their Fourier transform. Moreover, we discuss the differential properties of Chebyshev wavelets due the connection coefficients. The differential properties of Chebyshev wavelets, expressed by the connection coefficients (also called refinable integrals), are given by finite series in terms of the Kronecker delta. Moreover, we treat the p-order derivative of Chebyshev wavelets and compute its Fourier transform. Finally, we expand the mother wavelet in Taylor series with an application both in fractional calculus and fractal geometry.Keywords: Chebyshev wavelets, Fourier transform, connection coefficients, Taylor series, local fractional derivative, Cantor set
Procedia PDF Downloads 116846 Marine Propeller Cavitation Analysis Using BEM
Authors: Ehsan Yari
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In this paper, a numerical study of sheet cavitation has been performed on DTMB4119 and E779A marine propellers with the boundary element method. In propeller design, various parameters of geometry and fluid are incorporated. So a program is needed to solve the flow taking the whole parameters changing into account. The capability of analyzing the wetted and cavitation flow around propellers in steady, unsteady, uniform, and non-uniform conditions while decreasing computational time compared to numerical finite volume methods with acceptable precision are the characteristic features of the present method. Moreover, modifying the position of the detachment point and its corresponding potential value has been considered. Numerical results have been validated with experimental data, showing a good conformation.Keywords: cavitation, BEM, DTMB4119, E779A
Procedia PDF Downloads 64845 Structural Optimization, Design, and Fabrication of Dissolvable Microneedle Arrays
Authors: Choupani Andisheh, Temucin Elif Sevval, Bediz Bekir
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Due to their various advantages compared to many other drug delivery systems such as hypodermic injections and oral medications, microneedle arrays (MNAs) are a promising drug delivery system. To achieve enhanced performance of the MN, it is crucial to develop numerical models, optimization methods, and simulations. Accordingly, in this work, the optimized design of dissolvable MNAs, as well as their manufacturing, is investigated. For this purpose, a mechanical model of a single MN, having the geometry of an obelisk, is developed using commercial finite element software. The model considers the condition in which the MN is under pressure at the tip caused by the reaction force when penetrating the skin. Then, a multi-objective optimization based on non-dominated sorting genetic algorithm II (NSGA-II) is performed to obtain geometrical properties such as needle width, tip (apex) angle, and base fillet radius. The objective of the optimization study is to reach a painless and effortless penetration into the skin along with minimizing its mechanical failures caused by the maximum stress occurring throughout the structure. Based on the obtained optimal design parameters, master (male) molds are then fabricated from PMMA using a mechanical micromachining process. This fabrication method is selected mainly due to the geometry capability, production speed, production cost, and the variety of materials that can be used. Then to remove any chip residues, the master molds are cleaned using ultrasonic cleaning. These fabricated master molds can then be used repeatedly to fabricate Polydimethylsiloxane (PDMS) production (female) molds through a micro-molding approach. Finally, Polyvinylpyrrolidone (PVP) as a dissolvable polymer is cast into the production molds under vacuum to produce the dissolvable MNAs. This fabrication methodology can also be used to fabricate MNAs that include bioactive cargo. To characterize and demonstrate the performance of the fabricated needles, (i) scanning electron microscope images are taken to show the accuracy of the fabricated geometries, and (ii) in-vitro piercing tests are performed on artificial skin. It is shown that optimized MN geometries can be precisely fabricated using the presented fabrication methodology and the fabricated MNAs effectively pierce the skin without failure.Keywords: microneedle, microneedle array fabrication, micro-manufacturing structural optimization, finite element analysis
Procedia PDF Downloads 107844 Multi-Size Continuous Particle Separation on a Dielectrophoresis-Based Microfluidics Chip
Authors: Arash Dalili, Hamed Tahmouressi, Mina Hoorfar
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Advances in lab-on-a-chip (LOC) devices have led to significant advances in the manipulation, separation, and isolation of particles and cells. Among the different active and passive particle manipulation methods, dielectrophoresis (DEP) has been proven to be a versatile mechanism as it is label-free, cost-effective, simple to operate, and has high manipulation efficiency. DEP has been applied for a wide range of biological and environmental applications. A popular form of DEP devices is the continuous manipulation of particles by using co-planar slanted electrodes, which utilizes a sheath flow to focus the particles into one side of the microchannel. When particles enter the DEP manipulation zone, the negative DEP (nDEP) force generated by the slanted electrodes deflects the particles laterally towards the opposite side of the microchannel. The lateral displacement of the particles is dependent on multiple parameters including the geometry of the electrodes, the width, length and height of the microchannel, the size of the particles and the throughput. In this study, COMSOL Multiphysics® modeling along with experimental studies are used to investigate the effect of the aforementioned parameters. The electric field between the electrodes and the induced DEP force on the particles are modelled by COMSOL Multiphysics®. The simulation model is used to show the effect of the DEP force on the particles, and how the geometry of the electrodes (width of the electrodes and the gap between them) plays a role in the manipulation of polystyrene microparticles. The simulation results show that increasing the electrode width to a certain limit, which depends on the height of the channel, increases the induced DEP force. Also, decreasing the gap between the electrodes leads to a stronger DEP force. Based on these results, criteria for the fabrication of the electrodes were found, and soft lithography was used to fabricate interdigitated slanted electrodes and microchannels. Experimental studies were run to find the effect of the flow rate, geometrical parameters of the microchannel such as length, width, and height as well as the electrodes’ angle on the displacement of 5 um, 10 um and 15 um polystyrene particles. An empirical equation is developed to predict the displacement of the particles under different conditions. It is shown that the displacement of the particles is more for longer and lower height channels, lower flow rates, and bigger particles. On the other hand, the effect of the angle of the electrodes on the displacement of the particles was negligible. Based on the results, we have developed an optimum design (in terms of efficiency and throughput) for three size separation of particles.Keywords: COMSOL Multiphysics, Dielectrophoresis, Microfluidics, Particle separation
Procedia PDF Downloads 176843 Investigation on Behavior of Fixed-Ended Reinforced Concrete Deep Beams
Authors: Y. Heyrani Birak, R. Hizaji, J. Shahkarami
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Reinforced Concrete (RC) deep beams are special structural elements because of their geometry and behavior under loads. For example, assumption of strain- stress distribution is not linear in the cross section. These types of beams may have simple supports or fixed supports. A lot of research works have been conducted on simply supported deep beams, but little study has been done in the fixed-end RC deep beams behavior. Recently, using of fixed-ended deep beams has been widely increased in structures. In this study, the behavior of fixed-ended deep beams is investigated, and the important parameters in capacity of this type of beams are mentioned.Keywords: deep beam, capacity, reinforced concrete, fixed-ended
Procedia PDF Downloads 327842 Nonlinear Free Vibrations of Functionally Graded Cylindrical Shells
Authors: Alexandra Andrade Brandão Soares, Paulo Batista Gonçalves
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Using a modal expansion that satisfies the boundary and continuity conditions and expresses the modal couplings characteristic of cylindrical shells in the nonlinear regime, the equations of motion are discretized using the Galerkin method. The resulting algebraic equations are solved by the Newton-Raphson method, thus obtaining the nonlinear frequency-amplitude relation. Finally, a parametric analysis is conducted to study the influence of the geometry of the shell, the gradient of the functional material and vibration modes on the degree and type of nonlinearity of the cylindrical shell, which is the main contribution of this research work.Keywords: cylindrical shells, dynamics, functionally graded material, nonlinear vibrations
Procedia PDF Downloads 52