Search results for: distal radius

Authors: Francis O. Nwawuru

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The convergence analysis of split monotone inclusion problems and fixed point problems of certain nonlinear mappings are investigated in the setting of real Hilbert spaces. Inertial extrapolation term in the spirit of Polyak is incorporated to speed up the rate of convergence. Under standard assumptions, a strong convergence of the proposed algorithm is established without computing the resolvent operator or involving Yosida approximation method. The stepsize involved in the algorithm does not depend on the spectral radius of the linear operator. Furthermore, applications of the proposed algorithm in solving some related optimization problems are also considered. Our result complements and extends numerous results in the literature.

Keywords: fixedpoint, hilbertspace, monotonemapping, resolventoperators

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Authors: Y. Mateyshina, A.Ulihin, N.Uvarov

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Electrolytes with different type of charge carrier can find widely application in different using, e.g. sensors, electrochemical equipments, batteries and others. One of important components ensuring stable functioning of the equipment is electrolyte. Electrolyte has to be characterized by high conductivity, thermal stability, and wide electrochemical window. In addition to many advantageous characteristic for liquid electrolytes, the solid state electrolytes have good mechanical stability, wide working range of temperature range. Thus search of new system of solid electrolytes with high conductivity is an actual task of solid state chemistry. Families of alkali perchlorates and nitrates have been investigated by us earlier. In literature data about transport properties of alkali nitrites are absent. Nevertheless, alkali nitrites MeNO2 (Me= Li+, Na+, K+, Rb+ and Cs+), except for the lithium salt, have high-temperature phases with crystal structure of the NaCl-type. High-temperature phases of nitrites are orientationally disordered, i.e. non-spherical anions are reoriented over several equivalents directions in the crystal lattice. Pure lithium nitrite LiNO2 is characterized by ionic conductivity near 10-4 S/cm at 180°C and more stable as compared with lithium nitrate and can be used as a component for synthesis of composite electrolytes. In this work composite solid electrolytes in the binary system LiNO2 - A (A= MgO, -Al2O3, Fe2O3, CeO2, SnO2, SiO2) were synthesized and their structural, thermodynamic and electrical properties investigated. Alkali nitrite was obtained by exchange reaction from water solutions of barium nitrite and alkali sulfate. The synthesized salt was characterized by X-ray powder diffraction technique using D8 Advance X-Ray Diffractometer with Cu K radiation. Using thermal analysis, the temperatures of dehydration and thermal decomposition of salt were determined.. The conductivity was measured using a two electrode scheme in a forevacuum (6.7 Pa) with an HP 4284A (Precision LCR meter) in a frequency range 20 Hz < ν < 1 MHz. Solid composite electrolytes LiNO2 - A A (A= MgO, -Al2O3, Fe2O3, CeO2, SnO2, SiO2) have been synthesized by mixing of preliminary dehydrated components followed by sintering at 250°C. In the series of nitrite of alkaline metals Li+-Cs+, the conductivity varies not monotonically with increasing radius of cation. The minimum conductivity is observed for KNO2; however, with further increase in the radius of cation in the series, the conductivity tends to increase. The work was supported by the Russian Foundation for Basic research, grant #14-03-31442.

Keywords: conductivity, alkali nitrites, composite electrolytes, transport properties

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Authors: Neerja Gupta

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Objective-Reconstruction of large cavities of the breast without contralateral symmetrisation Background- Reconstruction of breast includes a wide spectrum of procedures from displacement to regional and distant flaps. The pedicled Perforator flaps cover a wide spectrum of reconstruction surgery for all quadrants of the breast, especially in patients with comorbidities. These axial flaps singly or adjunct are based on a near constant perforator vessel, a ratio of 2:1 at its entry in a flap is good to maintain vascularity. The perforators of lateral chest wall viz LICAP, LTAP have overlapping perfurosomes without clear demarcation. LTAP is localized in the narrow zone between the lateral breast fold and anterior axillary line,2.5-3.8cm from the fold. MICAP are localized at 1-2 cm from sternum. Being 1-2mm in diameter, a Single perforator is good to maintain the flap. LICAP has a dominant perforator in 6th-11th spaces, while LTAP has higher placed dominant perforators in 4th and 5th spaces. Methodology-Six consecutive patients who underwent reconstruction of the breast with pedicled perforator flaps were retrospectively analysed. Selections of the flap was done based on the size and locations of the tumour, anticipated volume loss, willingness to undergo contralateral symmetrisation, cosmetic expectations, and finances available.3 patients underwent vertical LTAP, the distal limit of the flap being the inframammary crease. 3 patients underwent MICAP, oriented along the axis of rib, the distal limit being the anterior axillary line. Preoperative identification was done using a unidirectional hand held doppler. The flap was raised caudal to cranial, the pivot point of rotation being the vessel entry into the skin. The donor area is determined by the skin pinch. Flap harvest time was 20-25 minutes. Intra operative vascularity was assessed with dermal bleed. The patient immediate pre, post-operative and follow up pics were compared independently by two breast surgeons. Patients were given a breast Q questionnaire (licensed) for scoring. Results-The median age of six patients was 46. Each patient had a hospital stay of 24 hours. None of the patients was willing for contralateral symmetrisation. The specimen dimensions were from 8x6.8x4 cm to 19x16x9 cm. The breast volume reconstructed range was 30 percent to 45 percent. All wide excision had free margins on frozen. The mean flap dimensions were 12x5x4.5 cm. One LTAP underwent marginal necrosis and delayed wound healing due to seroma. Three patients were phyllodes, of which one was borderline, and 2 were benign on final histopathology. All other 3 patients were invasive ductal cancer and have completed their radiation. The median follow up is 7 months the satisfaction scores at median follow of 7 months are 90 for physical wellbeing and 85 for surgical results. Surgeons scored fair to good in Harvard score. Conclusion- Pedicled perforator flaps are a valuable option for 3/8th volume of breast defects. LTAP is preferred for tumours at the Central, upper, and outer quadrants of the breast and MICAP for the inner and lower quadrant. The vascularity of the flap is dependent on the angiosomalterritories; adequate venous and cavity drainage.

Keywords: breast, oncoplasty, pedicled, perforator

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Authors: Aliouane Toufik, Hamdi Amine, Bouzid Djamel

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Aspheric optical components are an alternative to the use of conventional lenses in the implementation of imaging systems for the visible range. Spherical lenses are capable of producing aberrations. Therefore, they are not able to focus all the light into a single point. Instead, aspherical lenses correct aberrations and provide better resolution even with compact lenses incorporating a small number of lenses. Metrology of these components is very difficult especially when the resolution requirements increase and insufficient or complexity of conventional tools requires the development of specific approaches to characterization. This work is part of the problem existed because the objectives are the study and comparison of different methods used to measure surface rays hybrid aspherical lenses.

Keywords: manufacture of lenses, aspherical surface, precision molding, radius of curvature, roughness

Procedia PDF Downloads 443

Authors: Abdulrahman M. Homadi

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This study focuses on how to control the outlet temperature of a solar air heater in a way simpler than the existing methods. In this work, five cases have been studied by using ANSYS Fluent based on a CFD numerical method. All the cases have been simulated by utilizing the same criteria and conditions like the temperature, materials, areas except the geometry. The case studies are conducted in Little Rock (LR), AR, USA during the winter time supposedly on 15^th of December. A fresh air that is flowing with a velocity of 0.5 m/s and a flow rate of 0.009 m³/s. The results prove the possibility of achieving a controlled temperature just by changing the geometric shape of the heater. This geometry guarantees that the absorber plate always has a normal component of the solar radiation at any time during the day. The heater has a sectarian shape with a radius of 150 mm where the outlet temperature remains almost constant for six hours.

Keywords: solar energy, air heater, control of temperature, CFD

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Authors: Tan G. K. Y., Chew M. S. J., Sajeev S., Vellasamy A.

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Injuries of the extensor hallucis longus (EHL) tendon are a rare phenomenon, with most occurring due to lacerations or penetrating injuries. Closed traumatic ruptures of the EHL are described as “Mallet injuries of the toe”. These can be classified as bony or soft mallet injuries depending on the presence or absence of a fracture at the insertion site of the EHL tendon in the distal phalanx. We present a case of a 33-year-old woman who presented with a hyperflexion injury to the left big toe with an inability to extend the big toe. Ultrasound showed a complete rupture of the EHL tendon with retraction proximal to the hallucal interphalangeal joint of the big toe. The patient was treated through transarticular pinning and repair using the Arthrex Mini Bio-Suture Tak with a 2-0 fibre wire. Six months postoperatively, the patient had symmetrical EHL power and full range of motion of the toe. The lessons to be drawn from this case report are that isolated hallux mallet injuries are rare and can be easily missed in the absence of penetrating wounds. Patients who have such injuries should be investigated early with the appropriate imaging techniques, such as ultrasound or MRI, and treated surgically.

Keywords: hallux mallet, extensor hallucis longus tendon, extensor hallucis longus

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Authors: R. B. Mishra, Sudhakar Tripathi

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In this paper, the cable model of dendrites have been considered. The dendrites are cylindrical cables of various segments having variable length and reducing radius from start point at synapse and end points. For a particular event signal being received by a neuron in response only some dendrite are active at a particular instance. Initial current signals with different current flows in dendrite are assumed. Due to overlapping and coupling of active dendrite, they induce currents in the dendrite segments of each other at a particular instance. But how these currents are induced in the various segments of active dendrites due to coupling between these dendrites, It is not presented in the literature. Here the paper presents a model for induced currents in active dendrite segments due to mutual coupling at the starting instance of an activity in dendrite. The model is as discussed further.

Keywords: currents, dendrites, induction, simulation

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Authors: Abdel Moktader A. El Sayed, Nahla A. El Sayed

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Fifty-one sandstone core samples were obtained from the wadi Saal area. They belong to the Pre-Cenomanian age. These samples were subjected to various laboratory measurements such as density, porosity, permeability, electrical resistivity, grain size analysis and ultrasonic wave velocity. The parameters describing reservoir properties are outlined. The packing index, reservoir quality index, flow zone indicator and pore throat radius (R35 and R36) were calculated. The obtained interrelationships among these parameters allow improving petrophysical knowledge about the Pre-Cenomanian reservoir information. The obtained rock physics models could be employed with some precautions to the subsurface existences of the Pre-Cenomanian sandstone reservoirs, especially in the surrounding areas.

Keywords: resevoir sandstone, Egypt, Sinai, permeability

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Authors: M. G. Murtaza, E. E. Tzirtzilakis, M. Ferdows

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The mixed convective flow of MHD incompressible, steady boundary layer in heat transfer over a curved stretching sheet due to temperature dependent thermal conductivity is studied. We use curvilinear coordinate system in order to describe the governing flow equations. Finite difference solutions with central differencing have been used to solve the transform governing equations. Numerical results for the flow velocity and temperature profiles are presented as a function of the non-dimensional curvature radius. Skin friction coefficient and local Nusselt number at the surface of the curved sheet are discussed as well.

Keywords: curved stretching sheet, finite difference method, MHD, variable thermal conductivity

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Authors: M. Javadzadeh, H. Khoshsima

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In this article, we present a layout printing way for producing Fresnel zone on 1294-1b doped liquid crystal with Methyl-Red azo dye. We made a Fresnel zone mask with 25 zones and radius of 5 mm using lithography technique. With layout printing way, we recorded mask’s pattern on cell with λ=532 nm solid-state diode pump laser. By recording Fresnel zone pattern on cell and making Fresnel pattern on the surface of cell, odd and even zones, will form. The printed pattern, because of Azo dye’s photoisomerization, was permanent. Experimentally, we saw focal length tunability from 32 cm to 43 cm.

Keywords: liquid crystal, lens, Fresnel zone, diffraction, Fresnel lens

Procedia PDF Downloads 174

Authors: Lemonakis Panagiotis, Eliou Nikos, Karakasidis Theodoros, Botzoris George

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It is well known that trajectory along with speed are two of the most important contributing factors in road accidents. Trajectory is meant as the "line“, usually different from the center-line that a driver traverses through horizontal curves which depends on the characteristics of the road environment (especially the curvature), the vehicle and the driver himself. Drivers and especially riders, tend to broaden their paths in order to succeed greater path radiuses and hence, reduce the applied centrifugal force enhancing safety. The objective of the present research is to investigate riders’ path on horizontal curves. Within the context of the research, field measurements were conducted on a rural two lane highway, with the participation of eight riders and the use of an instrumented motorcycle. The research has shown that the trajectory of the riders is correlated to the radius and the length of the horizontal curve as well.

Keywords: trajectory, path, riders, horizontal curves

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Authors: Cheng-Chi Yu, Yu-Shiue Wang, Kei-Lin Kuo

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Active Independent Front Steering system is a steering system which can according to vehicle driving situation adjusts the relation of steering angle between inner wheel and outer wheel. In low-speed cornering, AIFS sets the steering angles of inner and outer wheel into Ackerman steering geometry to make vehicle has less cornering radius. Besides, AIFS changes the steering geometry to parallel or even anti-Ackerman steering geometry to keep vehicle stability in high-speed cornering. Therefore, based on the analysis of the vehicle steering behavior from different steering geometries, this study develops a new screw type of active independent front steering system to make vehicles best cornering performance at any speeds. The screw type of active independent front steering system keeps the pinion and separates the rack into main rack and second rack. Two racks connect by a screw. Extra screw rotated motion powered by assistant motor through coupler makes second rack move relative to main rack, which can adjust both steering ratio and steering geometry. First of all, this study distinguishes the steering geometry by using Ackerman percentage and utilizes the software of ADAMS/Car to construct diverse steering geometry models. The different steering geometries are compared at low-speed and high-speed cornering, and then control strategies of the active independent front steering systems could be formulated. Secondly, this study applies closed loop equation to analyze tire steering angles and carries out optimization calculations to make the steering geometry from traditional rack and pinion steering system near to Ackerman steering geometry. Steering characteristics of the optimum steering mechanism and motion characteristics of vehicle installed the steering mechanism are verified by ADAMS/Car models of front suspension and full vehicle respectively. By adding dual auxiliary rack and dual motor to the optimum steering mechanism, the active independent front steering system could be developed to achieve the functions of variable steering ratio and variable steering geometry. At last, this study uses ADAMS/Car and Matlab/Simulink to co-simulate the cornering motion of vehicles confirms the vehicle installed the Active Independent Front Steering (AIFS) system has better handling performance than that with Active Independent Steering (AFS) system or with Electric Power Steering (EPS) system. At low-speed cornering, the vehicles with AIFS system and with AFS system have better maneuverability, less cornering radius, than the traditional vehicle with EPS system because that AIFS and AFS systems both provide function of variable steering ratio. However, there is a slight penalty in the motor(s) power consumption. In addition, because of the capability of variable steering geometry, the vehicle with AIFS system has better high-speed cornering stability, trajectory keeping, and even less motor(s) power consumption than that with EPS system and also with AFS system.

Keywords: active front steering system, active independent front steering system, steering geometry, steering ratio

Procedia PDF Downloads 156

Authors: Haifeng Zhou, Tsungyang Liow, Xiaoguang Tu, Eujin Lim, Chao Li, Junfeng Song, Xianshu Luo, Ying Huang, Lianxi Jia, Lianwee Luo, Kim Dowon, Qing Fang, Mingbin Yu, Guoqiang Lo

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Several Germanium photodetectors (PD) built on silicon micro-disks are fabricated on the standard Si photonics multiple project wafers (MPW) and demonstrated to exhibit very low dark current, satisfactory operation bandwidth and moderate responsivity. Among them, a vertical p-i-n Ge PD based on a 2.0 µm-radius micro-disk has a dark current of as low as 35 nA, compared to a conventional PD current of 1 µA with an area of 100 µm2. The operation bandwidth is around 15 GHz at a reverse bias of 1V. The responsivity is about 0.6 A/W. Microdisk is a striking planar structure in integrated optics to enhance light-matter interaction and construct various photonics devices. The disk geometries feature in strongly and circularly confining light into an ultra-small volume in the form of whispering gallery modes. A laser may benefit from a microdisk in which a single mode overlaps the gain materials both spatially and spectrally. Compared to microrings, micro-disk removes the inner boundaries to enable even better compactness, which also makes it very suitable for some scenarios that electrical connections are needed. For example, an ultra-low power (≈ fJ) athermal Si modulator has been demonstrated with a bit rate of 25Gbit/s by confining both photons and electrically-driven carriers into a microscale volume.In this work, we study Si-based PDs with Ge selectively grown on a microdisk with the radius of a few microns. The unique feature of using microdisk for Ge photodetector is that mode selection is not important. In the applications of laser or other passive optical components, microdisk must be designed very carefully to excite the fundamental mode in a microdisk in that essentially the microdisk usually supports many higher order modes in the radial directions. However, for detector applications, this is not an issue because the local light absorption is mode insensitive. Light power carried by all modes are expected to be converted into photo-current. Another benefit of using microdisk is that the power circulation inside avoids any introduction of the reflector. A complete simulation model with all involved materials taken into account is established to study the promise of microdisk structures for photodetector by using finite difference time domain (FDTD) method. By viewing from the current preliminary data, the directions to further improve the device performance are also discussed.

Keywords: integrated optical devices, silicon photonics, micro-resonator, photodetectors

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Authors: A. Ja, J. Belabid, A. Cheddadi

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This paper reports the numerical simulation of double diffusive natural convection flows within a horizontal annular filled with a saturated porous medium. The analysis concerns the influence of the different parameters governing the problem, namely, the Rayleigh number Ra, the Lewis number Le and the buoyancy ratio N, on the heat and mass transfer and on the flow structure, in the case of a fixed radius ratio R = 2. The numerical model used for the discretization of the dimensionless equations governing the problem is based on the finite difference method, using the ADI scheme. The study is focused on steady-state solutions in the cooperation situation.

Keywords: natural convection, double-diffusion, porous medium, annular geometry, finite differences

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Authors: M. Fatmi, B. Gueridi, Z. Zerrougui

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Some physical properties of hexahalometallate K₂XBr₆(X=Se, Pt) were computed in the zinc blend structure using generalized gradient approximation. The cell constant of K₂SeBr₆ and K₂PtBr₆ is consistent with the experiment value quoted in the literature, where the error is 0.95 % and 1 %. K₂SeBr₆ and K₂PtBr₆ present covalent bonding, high anisotropy and are ductile. The elastic constants of K₂SeBr₆ and K₂PtBr₆ are significantly smaller due to their larger reticular distances and lower Colombian forces, and then they are soft and damage tolerant. The interatomic separation is greater in K₂SeBr₆ than in K₂PtBr₆; hence the Colombian interaction in K₂PtBr₆ is greater than that of K2SeBr₆. The internal coordinate of the Br atom in K₂PtBr₆ is lower than that of the same atom in K2SeBr₆, and this can be explained by the fact that it is inversely proportional to the atom radius of Se and Pt. There are two major plasmonic processes, with intensities of 3.7 and 1.35, located around 53.5 nm and 72.8 nm for K₂SeBr₆ and K₂PtBr₆.

Keywords: hexahalometallate, band structure, morphology, absorption, band gap, absorber

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Authors: Youping Dai, Xinping Dai, Xiaoyun Li

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In this paper, the effect of Cosmic Background Gravitational Potential (CBGP) was discussed. It is helpful to reveal the equivalence of gravitational and inertial mass, and to understand the origin of inertia. The derivation is similar to the classic approach adopted by Landau in the book 'Classical Theory of Fields'.The main differences are that we used CBGP = Lambda^2 instead of c^2, and used CBGP energy E = m*Lambda^2 instead of kinetic energy E = (1/2)m*v^2 as initial assumptions (where Lambda has the same units for measuring velocity). It showed that Lorentz transformation, rest energy and Newtonian mechanics are all affected by $CBGP$, and the square of the speed of light is equal to CBGP too. Finally, the top value of cosmic mass density and cosmic radius were discussed.

Keywords: the origin of inertia, Mach's principle, equivalence principle, cosmic background potential

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Authors: Yan Rongxin, Sun Wei, Li Weidan

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Based on the acoustics cascade sound theory, the mechanism of air leak sound producing, transmitting and signal detecting has been analyzed. A formula of the sound power, leak size and air pressure in the spacecraft has been built, and the relationship between leak sound pressure and receiving direction and distance has been studied. The center frequency in millimeter diameter leak is more than 20 kHz. The situation of air leaking from spacecraft to space has been simulated and an experiment of different leak size and testing distance and direction has been done. The sound pressure is in direct proportion to the cosine of the angle of leak to sensor. The portable ultrasonic leak detector has been developed, whose minimal leak rate is 10^-1 Pa·m³/s, the testing radius is longer than 20 mm, the mass is less than 1.0 kg, and the electric power is less than 2.2 W.

Keywords: leak testing, manned spacecraft, sound transmitting, ultrasonic

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Authors: M. Tan, N. N. Wan, N. Ramli, N. H. Hassan

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Car drivers would always like to have custom wheel on their car for two reasons; to improve their car's aesthetic beauty and to improve their car handling. As the size of the rims or wheels played an important role in influencing the way of car handles around turns, this paper aims to present the optimality of rim size that drivers should have known while changing their rim. There are three factors that drivers should have considered while changing their rim: rim size, its weight and material of which they are made. Using mathematical analysis, this paper will focus on only one factor, which is rim size. Factors that are considered in calculating the optimum rim size are the vehicle rim radius, tire height and weight, and aspect ratio. This paper has found that there are limitations in percentage change in rim size from the original tire size. Failure to have the right offset size may cause problems in maneuvering the vehicle.

Keywords: mathematical analysis, optimum wheel size, percentage change, custom wheel

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Authors: A. Amiri Delouei

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In the current study, two-dimensional unsteady heat conduction in a functionally graded cylinder is studied analytically. The temperature distribution is in radial and longitudinal directions. Heat conduction coefficients are considered a power function of radius both in radial and longitudinal directions. The proposed solution can exactly satisfy the boundary conditions. Analytical unsteady temperature distribution for different parameters of functionally graded cylinder is investigated. The achieved exact solution is useful for thermal stress analysis of functionally graded cylinders. Regarding the analytical approach, this solution can be used to understand the concepts of heat conduction in functionally graded materials.

Keywords: functionally graded materials, unsteady heat conduction, cylinder, temperature distribution

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Authors: Sarah A. Goodchild, Rachel Gao, Philip N. Bartlett

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A novel detection approach using immobilized DNA probes labeled with Anthraquinone (AQ) as an electrochemically active reporter moiety has been successfully developed as a new, simple, reliable method for the detection of DNA. This method represents a step forward in DNA detection as it can discriminate between multiple nucleotide polymorphisms within target DNA strands without the need for any additional reagents, reporters or processes such as melting of DNA strands. The detection approach utilizes single-stranded DNA probes immobilized on gold surfaces labeled at the distal terminus with AQ. The effective immobilization has been monitored using techniques such as AC impedance and Raman spectroscopy. Simple voltammetry techniques (Differential Pulse Voltammetry, Cyclic Voltammetry) are then used to monitor the reduction potential of the AQ before and after the addition of complementary strand of target DNA. A reliable relationship between the shift in reduction potential and the number of base pair mismatch has been established and can be used to discriminate between DNA from highly related pathogenic organisms of clinical importance. This indicates that this approach may have great potential to be exploited within biosensor kits for detection and diagnosis of pathogenic organisms in Point of Care devices.

Keywords: Anthraquinone, discrimination, DNA detection, electrochemical biosensor

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Authors: ELdessouky Sheta, Sayed Elzomor, Haithem Farghali, Kawkab A. Ahmed, Naglaa A. Abd Elkader

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The present investigation has been dealt with Spirocerca (S.) lupi infested mongrel dogs. This parasitic disease is highly infective to human beings and carnivores. The diagnosis march has been comprised the lateral contrast thoracic radiographs, fecal examination, blood profile, endoscopic examination and histopathological sections of deep seated pinch biopsies. These infested dogs have been put under an adopted treatment with Ivermectin injection combined with oral prednisolone. The obtained results reveal an absence of the pessimistic recognitions particularly after 3 weeks from the onset of treatment. Endoscopically the presented esophageal nodules are marked out in the distal third of infested dogs' esophagus as masses assigned into the esophageal lumen and fundus of stomach. The endoscopic outlook of Spirocerca lupi lesions has been considered an integral procedure of the diagnostic march and for evaluation of treatment follow up. The diagnostic procedures and the recommended treatment are the vet's guidance to care for Spirocerca lupi in dogs, hoping in future to prevent this disease from being spread among human beings and other carnivores.

Keywords: endoscopy, esophagus, stomach spirocercosis, dogs

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Authors: Vinod Kumar Arya

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Creep analysis of a thick-walled composite anisotropic cylinder under internal pressure and considering large strains is presented. Using a threshold creep law for composite materials, expressions for stresses, strains, and strain rates are derived for several anisotropic cases. Numerical results, presented through several graphs and tables, depict the effect of anisotropy on the stress, strain, and strain rate distributions. Since for a specific type of material anisotropy described in the paper, these quantities are found to have the lowest values at the inner radius (the potential location of cylinder failure), it is concluded that by employing such an anisotropic material for the design of a thick-walled cylinder a longer service life for the cylinder may be achieved.

Keywords: creep, composites, large strains, thick-walled cylinders, anisotropy

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Authors: Yasser Abo El-Magd, Wael Fawzy Mohamed

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Due to the great development in construction and building field, there are many projects and huge works appeared which consume many construction materials. Accordingly, that causes difficulty in handling traditional transportation means (ordinary cranes) due to their limited capacity; there is an urgent need to use high capacity cranes such as tower cranes. However, with regard to their high expense, we have to take into consideration selecting what type of cranes to be utilized which has been discussed by many researchers. In this research, a proposed technique was created to select the suitable type of crane and the best place for crane erection, in addition to minimum radius for requested crane in order to minimize cost. To fulfill that target, a computer program is designed to numerate these problems, demonstrating an example explaining how to apply program and the result donated the best place.

Keywords: tower crane, jib length, operating time, location, feasible area

Procedia PDF Downloads 191

Authors: Youssef I. Hafez

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Since ancient history rivers have been the fostering and favorite place for people and civilizations to live and exist along river banks. However, due to floods and droughts, especially sever conditions due to global warming and climate change, river channels are completely evolving and moving in the lateral direction changing their plan form either through straightening of curved reaches (meander cut-off) or increasing meandering curvature. The lateral shift or shrink of a river channel affects severely the river banks and the flood plain with tremendous impact on the surrounding environment. Therefore, understanding the formation and the continual processes of river channel meandering is of paramount importance. So far, in spite of the huge number of publications about river-meandering, there has not been a satisfactory theory or approach that provides a clear explanation of the formation of river meanders and the mechanics of their associated geometries. In particular two parameters are often needed to describe meander geometry. The first one is a scale parameter such as the meander arc length. The second is a shape parameter such as the maximum angle a meander path makes with the channel mean down path direction. These two parameters, if known, can determine the meander path and geometry as for example when they are incorporated in the well known sine-generated curve. In this study, a uniform excess energy theory is used to illustrate the origin and mechanics of formation of river meandering. This theory advocates that the longitudinal imbalance between the valley and channel slopes (with the former is greater than the second) leads to formation of curved meander channel in order to reduce the excess energy through its expenditure as transverse energy loss. Two relations are developed based on this theory; one for the determination of river channel radius of curvature at the bend apex (shape parameter) and the other for the determination of river channel sinuosity. The sinuosity equation tested very well when applied to existing available field data. In addition, existing model data were used to develop a relation between the meander arc length and the Darcy-Weisback friction factor. Then, the meander wave length was determined from the equations of the arc length and the sinuosity. The developed equation compared well with available field data. Effects of the transverse bed slope and grain size on river channel sinuosity are addressed. In addition, the concept of maximum channel sinuosity is introduced in order to explain the changes of river channel plan form due to changes in flow discharges and sediment loads induced by global warming and climate changes.

Keywords: river channel meandering, sinuosity, radius of curvature, meander arc length, uniform excess energy theory, transverse energy loss, transverse bed slope, flow discharges, sediment loads, grain size, climate change, global warming

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Authors: Radhe Tado, Ashish B. Deoghare, K. M. Pandey

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The aim of this study is to estimate the effect of blood flow through the coronary artery in human heart so as to assess the coronary artery disease.Velocity, wall shear stress (WSS), strain rate and wall pressure distribution are some of the important hemodynamic parameters that are non-invasively assessed with computational fluid dynamics (CFD). These parameters are used to identify the mechanical factors responsible for the plaque progression and/or rupture in left coronary arteries (LCA) in coronary arteries.The initial step for CFD simulations was the construction of a geometrical model of the LCA. Patient specific artery model is constructed using computed tomography (CT) scan data with the help of MIMICS Research 19.0. For CFD analysis ANSYS FLUENT-14.5 is used.Hemodynamic parameters were quantified and flow patterns were visualized both in the absence and presence of coronary plaques. The wall pressure continuously decreased towards distal segments and showed pressure drops in stenotic segments. Areas of high WSS and high flow velocities were found adjacent to plaques deposition.

Keywords: angiography, computational fluid dynamics (CFD), time-average wall shear stress (TAWSS), wall pressure, wall shear stress (WSS)

Procedia PDF Downloads 158

Authors: A. Beatti, L. Chipchase, A. Rayner, T. Souvlis

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The aims of this study were to investigate the depth of interferential current (IFC) penetration through soft tissue and to investigate the area over which IFC spreads during clinical application. Premodulated IFC and ‘true’ IFC at beat frequencies of 4, 40 and 90Hz were applied via four electrodes to the distal medial thigh of 15 healthy subjects. The current was measured via three Teflon coated fine needle electrodes that were inserted into the superficial layer of skin, then into the subcutaneous tissue (≈1 cm deep) and then into muscle tissue (≈2 cm deep). The needle electrodes were placed in the middle of the four IFC electrodes, between two channels and outside the four electrodes. Readings were taken at each tissue depth from each electrode during each treatment frequency then digitized and stored for analysis. All voltages were greater at all depths and locations than baseline (p < 0.01) and voltages decreased with depth (P=0.039). Lower voltages of all currents were recorded in the middle of the four electrodes with the highest voltage being recorded outside the four electrodes in all depths (P=0.000).For each frequency of ‘true’ IFC, the voltage was higher in the superficial layer outside the electrodes (P ≤ 0.01).Premodulated had higher voltages along the line of one circuit (P ≤ 0.01). Clinically, IFC appears to pass through skin layers to depth and is more efficient than premodulated IFC when targeting muscle tissue.

Keywords: electrotherapy, interferential current, interferential therapy, medium frequency current

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Authors: Dirk Briskorn, Michael Dienstknecht

Abstract:

Cranes are a key element in construction projects as they are the primary lifting equipment and among the most expensive construction equipment. Thus, selecting cranes and locating them on-site is an important factor for a project's profitability. We focus on a site with supply and demand areas that have to be connected by tower cranes. There are several types of tower cranes differing in certain specifications such as costs or operating radius. The objective is to select cranes and determine their locations such that each demand area is connected to its supply area at minimum cost. We detail the problem setting and show how to obtain a discrete set of candidate locations for each crane type without losing optimality. This discretization allows us to reduce our problem to the classic set cover problem. Despite its NP-hardness, we achieve good results employing a standard solver and a greedy heuristic, respectively.

Keywords: positioning, selection, standard solver, tower cranes

Procedia PDF Downloads 342

Authors: Ewelina Nowak, Anna Wisla-Swider, Krzysztof Danel

Abstract:

Aqueous suspensions of DNA were illuminated with linearly polarized visible light and ultraviolet for 5, 15, 20 and 40 h. In order to check the nature of modification, DNA interactions were characterized by FTIR spectroscopy. For each illuminated sample, weight average molecular weight and hydrodynamic radius were measured by high pressure size exclusion chromatography. Resulting optical changes for illuminated DNA were investigated using UV-Vis spectra and photoluminescent. Optical properties show potential application in sensors based on modified DNA. Then selected DNA-surfactant complexes were illuminated with electromagnetic radiation for 5h. Molecular structure, optical characteristic were examinated for obtained complexes. Illumination led to changes of complexes physicochemical properties as compared with native DNA. Observed changes were induced by rearrangement of the molecular structure of DNA chains.

Keywords: biopolymers, deoxyribonucleic acid, ionic liquids, linearly polarized visible light, ultraviolet

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Authors: Mohsen Farshad

Abstract:

Information and force definition has been intertwined with the concept of entropy for many years. The displacement information of degrees of freedom with Brownian motions at a given temperature in space emerges as an entropic force between species. Here, we use this concept of entropy to understand the underlying physics behind the formation of attractive and repulsive forces by imagining that space is filled with free Brownian degrees of freedom. We incorporate the radius of bodies and the distance between them into entropic force relation systematically. Using this modified gravitational entropic force, we derive the attractive entropic force between bodies without considering their spin. We further hypothesize a possible mechanism for the formation of the repulsive force between two bodies. We visually elaborate that the repulsive entropic force will be manifested through the rotation of degrees of freedom around the spinning particles.

Keywords: entropy, information, force, Brownian Motions

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Authors: U. V. S. Seshavatharam, S. Lakshminarayana

Abstract:

In a unified approach observed cosmic red shift can be re-interpreted as an index of cosmological galactic atomic light emission phenomenon. By increasing the applications of Hubble volume in cosmology as well as in quantum physics, concepts of ‘Black Hole Cosmology’ can be well-confirmed. Clearly speaking ‘quantum mechanics’ can be shown to be a branch of ‘black hole cosmology’. In Big Bang Model, confirmation of all the observations directly depend on the large scale galactic distances that are beyond human reach and raise ambiguity in all respects. The subject of modern black hole physics is absolutely theoretical. Advantage of Black hole cosmology lies in confirming its validity through the ground based atomic and nuclear experimental results.

Keywords: Hubble volume, black hole cosmology, CMBR energy density, Planck’s constant, fine structure ratio, cosmic time, nuclear charge radius, unification

Procedia PDF Downloads 539