Search results for: Mössbauer measurements.
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 878

Search results for: Mössbauer measurements.

698 Optoelectronic Automated System for Length and Profile Measurements

Authors: L. C. Gómez-Pavón, M. A. Rojas Aparicio, E. Juárez Ruiz, M. A. Flores Guerrero, and O. Gómez-de la Fuente

Abstract:

In this work the design and characterization of an optoelectronic automated measurement system it is presented. The optoelectronic devices of this system are an optical transmitter, the optical components and the optical receiver, which were selected for a great precision of the system. The mechanical system allows free displacement of the components as well as the devices that generate the movement. The results, length and profile of the objects are display in Lab View.

Keywords: Automated, optoelectronic, triangulation method.

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697 Kalman Filter for Bilinear Systems with Application

Authors: Abdullah E. Al-Mazrooei

Abstract:

In this paper, we present a new kind of the bilinear systems in the form of state space model. The evolution of this system depends on the product of state vector by its self. The well known Lotak Volterra and Lorenz models are special cases of this new model. We also present here a generalization of Kalman filter which is suitable to work with the new bilinear model. An application to real measurements is introduced to illustrate the efficiency of the proposed algorithm.

Keywords: Bilinear systems, state space model, Kalman filter.

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696 Assessment of Path Loss Prediction Models for Wireless Propagation Channels at L-Band Frequency over Different Micro-Cellular Environments of Ekiti State, Southwestern Nigeria

Authors: C. I. Abiodun, S. O. Azi, J. S. Ojo, P. Akinyemi

Abstract:

The design of accurate and reliable mobile communication systems depends majorly on the suitability of path loss prediction methods and the adaptability of the methods to various environments of interest. In this research, the results of the adaptability of radio channel behavior are presented based on practical measurements carried out in the 1800 MHz frequency band. The measurements are carried out in typical urban, suburban and rural environments in Ekiti State, Southwestern part of Nigeria. A total number of seven base stations of MTN GSM service located in the studied environments were monitored. Path loss and break point distances were deduced from the measured received signal strength (RSS) and a practical path loss model is proposed based on the deduced break point distances. The proposed two slope model, regression line and four existing path loss models were compared with the measured path loss values. The standard deviations of each model with respect to the measured path loss were estimated for each base station. The proposed model and regression line exhibited lowest standard deviations followed by the Cost231-Hata model when compared with the Erceg Ericsson and SUI models. Generally, the proposed two-slope model shows closest agreement with the measured values with a mean error values of 2 to 6 dB. These results show that, either the proposed two slope model or Cost 231-Hata model may be used to predict path loss values in mobile micro cell coverage in the well-considered environments. Information from this work will be useful for link design of microwave band wireless access systems in the region.

Keywords: Break-point distances, path loss models, path loss exponent, received signal strength.

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695 Genetic Algorithms in Hot Steel Rolling for Scale Defect Prediction

Authors: Jarno Haapamäki, Juha Röning

Abstract:

Scale defects are common surface defects in hot steel rolling. The modelling of such defects is problematic and their causes are not straightforward. In this study, we investigated genetic algorithms in search for a mathematical solution to scale formation. For this research, a high-dimensional data set from hot steel rolling process was gathered. The synchronisation of the variables as well as the allocation of the measurements made on the steel strip were solved before the modelling phase.

Keywords: Genetic algorithms, hot strip rolling, knowledge discovery, modeling.

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694 Effects of Free-Hanging Horizontal Sound Absorbers on the Cooling Performance of Thermally Activated Building Systems

Authors: L. Marcos Domínguez, Nils Rage, Ongun B. Kazanci, Bjarne W. Olesen

Abstract:

Thermally Activated Building Systems (TABS) have proven to be an energy-efficient solution to provide buildings with an optimal indoor thermal environment. This solution uses the structure of the building to store heat, reduce the peak loads, and decrease the primary energy demand. TABS require the heated or cooled surfaces to be as exposed as possible to the indoor space, but exposing the bare concrete surfaces has a diminishing effect on the acoustic qualities of the spaces in a building. Acoustic solutions capable of providing optimal acoustic comfort and allowing the heat exchange between the TABS and the room are desirable. In this study, the effects of free-hanging units on the cooling performance of TABS and the occupants’ thermal comfort was measured in a full-scale TABS laboratory. Investigations demonstrate that the use of free-hanging sound absorbers are compatible with the performance of TABS and the occupant’s thermal comfort, but an appropriate acoustic design is needed to find the most suitable solution for each case. The results show a reduction of 11% of the cooling performance of the TABS when 43% of the ceiling area is covered with free-hanging horizontal sound absorbers, of 23% for 60% ceiling coverage ratio and of 36% for 80% coverage. Measurements in actual buildings showed an increase of the room operative temperature of 0.3 K when 50% of the ceiling surface is covered with horizontal panels and of 0.8 to 1 K for a 70% coverage ratio. According to numerical simulations using a new TRNSYS Type, the use of comfort ventilation has a considerable influence on the thermal conditions in the room; if the ventilation is removed, then the operative temperature increases by 1.8 K for a 60%-covered ceiling.

Keywords: Acoustic comfort, concrete core activation, full-scale measurements, thermally activated building systems, TRNSYS.

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693 Simulation and Measurement the Radiation of an Antenna inside a Metallic Case using FDTD

Authors: Shabnam Ladan, M. S. Abrishamian

Abstract:

In this paper we have developed a FDTD simulation code which can treat wave propagation of a monopole antenna in a metallic case which covers with PML, and performed a series of three dimensional FDTD simulations of electromagnetic wave propagation in this space .We also provide a measurement set up in antenna lab and fortunately the simulations and measurements show good agreement. According to simulation and measurement results, we confirmed that the computer program which had been written in FORTRAN, works correctly.

Keywords: FDTD, EMC, monopole antenna.

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692 Assessing Overall Thermal Conductance Value of Low-Rise Residential Home Exterior Above-Grade Walls Using Infrared Thermography Methods

Authors: Matthew D. Baffa

Abstract:

Infrared thermography is a non-destructive test method used to estimate surface temperatures based on the amount of electromagnetic energy radiated by building envelope components. These surface temperatures are indicators of various qualitative building envelope deficiencies such as locations and extent of heat loss, thermal bridging, damaged or missing thermal insulation, air leakage, and moisture presence in roof, floor, and wall assemblies. Although infrared thermography is commonly used for qualitative deficiency detection in buildings, this study assesses its use as a quantitative method to estimate the overall thermal conductance value (U-value) of the exterior above-grade walls of a study home. The overall U-value of exterior above-grade walls in a home provides useful insight into the energy consumption and thermal comfort of a home. Three methodologies from the literature were employed to estimate the overall U-value by equating conductive heat loss through the exterior above-grade walls to the sum of convective and radiant heat losses of the walls. Outdoor infrared thermography field measurements of the exterior above-grade wall surface and reflective temperatures and emissivity values for various components of the exterior above-grade wall assemblies were carried out during winter months at the study home using a basic thermal imager device. The overall U-values estimated from each methodology from the literature using the recorded field measurements were compared to the nominal exterior above-grade wall overall U-value calculated from materials and dimensions detailed in architectural drawings of the study home. The nominal overall U-value was validated through calendarization and weather normalization of utility bills for the study home as well as various estimated heat loss quantities from a HOT2000 computer model of the study home and other methods. Under ideal environmental conditions, the estimated overall U-values deviated from the nominal overall U-value between ±2% to ±33%. This study suggests infrared thermography can estimate the overall U-value of exterior above-grade walls in low-rise residential homes with a fair amount of accuracy.

Keywords: Emissivity, heat loss, infrared thermography, thermal conductance.

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691 Effect of Plunging Oscillation on an Offshore Wind Turbine Blade Section

Authors: F. Rasi Marzabadi

Abstract:

A series of experiments were carried out to study unsteady behavior of the flow field as well as the boundary layer of an airfoil oscillating in plunging motion in a subsonic wind tunnel. The measurements involved surface pressure distribution complimented with surface-mounted hot-films. The effect of leadingedge roughness that simulates surface irregularities on the wind turbine blades was also studied on variations of aerodynamic loads and boundary layer behavior.

Keywords: Boundary layer transition, plunging, reduced frequency, wind turbine.

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690 Carbon Nanotubes with Magnetic Particles

Authors: Svitlana Kopyl, Vladimir Bystrov, Mikhail Maiorov, Manuel Valente, Igor Bdikin, Antonio C.M. Sousa

Abstract:

Magnetic carbon nanotubes composites were obtained by filling carbon nanotubes with paramagnetic iron oxide particles. Detailed investigation of magnetic behaviour of resulting composites was done at different temperatures. Measurements indicate that these functionalized nanotubes are superparamagnetic at room temperature; however, no superparamagnetism was observed at 125 K and 80 K. The blocking temperature TB was estimated at 145 K. These magnetic carbon nanotubes have the potential of being used in a wide range of applications, in particular, the production of nanofluids, which can be controlled and steered by appropriate magnetic fields.

Keywords: carbon nanotubes, magnetic nanoparticles, magnetization, nanofluids

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689 A New Approach to Signal Processing for DC-Electromagnetic Flowmeters

Authors: Michael Schukat

Abstract:

Electromagnetic flowmeters with DC excitation are used for a wide range of fluid measurement tasks, but are rarely found in dosing applications with short measurement cycles due to the achievable accuracy. This paper will identify a number of factors that influence the accuracy of this sensor type when used for short-term measurements. Based on these results a new signal-processing algorithm will be described that overcomes the identified problems to some extend. This new method allows principally a higher accuracy of electromagnetic flowmeters with DC excitation than traditional methods.

Keywords: Electromagnetic Flowmeter, Kalman Filter, ShortMeasurement Cycles, Signal Estimation

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688 Application of Fuzzy Neural Network for Image Tumor Description

Authors: Nahla Ibraheem Jabbar, Monica Mehrotra

Abstract:

This paper used a fuzzy kohonen neural network for medical image segmentation. Image segmentation plays a important role in the many of medical imaging applications by automating or facilitating the diagnostic. The paper analyses the tumor by extraction of the features of (area, entropy, means and standard deviation).These measurements gives a description for a tumor.

Keywords: FCM, features extraction, medical image processing, neural network, segmentation.

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687 MIMO Radar-Based System for Structural Health Monitoring and Geophysical Applications

Authors: Davide D’Aria, Paolo Falcone, Luigi Maggi, Aldo Cero, Giovanni Amoroso

Abstract:

The paper presents a methodology for real-time structural health monitoring and geophysical applications. The key elements of the system are a high performance MIMO RADAR sensor, an optical camera and a dedicated set of software algorithms encompassing interferometry, tomography and photogrammetry. The MIMO Radar sensor proposed in this work, provides an extremely high sensitivity to displacements making the system able to react to tiny deformations (up to tens of microns) with a time scale which spans from milliseconds to hours. The MIMO feature of the system makes the system capable of providing a set of two-dimensional images of the observed scene, each mapped on the azimuth-range directions with noticeably resolution in both the dimensions and with an outstanding repetition rate. The back-scattered energy, which is distributed in the 3D space, is projected on a 2D plane, where each pixel has as coordinates the Line-Of-Sight distance and the cross-range azimuthal angle. At the same time, the high performing processing unit allows to sense the observed scene with remarkable refresh periods (up to milliseconds), thus opening the way for combined static and dynamic structural health monitoring. Thanks to the smart TX/RX antenna array layout, the MIMO data can be processed through a tomographic approach to reconstruct the three-dimensional map of the observed scene. This 3D point cloud is then accurately mapped on a 2D digital optical image through photogrammetric techniques, allowing for easy and straightforward interpretations of the measurements. Once the three-dimensional image is reconstructed, a 'repeat-pass' interferometric approach is exploited to provide the user of the system with high frequency three-dimensional motion/vibration estimation of each point of the reconstructed image. At this stage, the methodology leverages consolidated atmospheric correction algorithms to provide reliable displacement and vibration measurements.

Keywords: Interferometry, MIMO RADAR, SAR, tomography.

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686 Dynamical Analysis of Circadian Gene Expression

Authors: Carla Layana Luis Diambra

Abstract:

Microarrays technique allows the simultaneous measurements of the expression levels of thousands of mRNAs. By mining this data one can identify the dynamics of the gene expression time series. By recourse of principal component analysis, we uncover the circadian rhythmic patterns underlying the gene expression profiles from Cyanobacterium Synechocystis. We applied PCA to reduce the dimensionality of the data set. Examination of the components also provides insight into the underlying factors measured in the experiments. Our results suggest that all rhythmic content of data can be reduced to three main components.

Keywords: circadian rhythms, clustering, gene expression, PCA.

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685 Pd(II) Complex with 4-Bromo-Bis-Hydroxymethyl Phenol and Nicotinamide: Synthesis and Spectral Analysis

Authors: Özlen Altun, Zeliha Yoruç

Abstract:

In the present study, the reactions involving 4-bromo-2,6-bis-hydroxymethyl-phenol (BBHMP) and nicotinamide (NA) in the presence of Pd(II) ions were investigated. Optimum conditions for the reactions were established as pH = 7 and λ = 450 nm. According to absorbance measurements, the molar ratio of BBHMP: NA: Pd2+ was found to be 1: 2: 2. As a result of physicochemical, spectrophotometric and thermal analyses, the reactions of BBHMP and NA with Pd(II) are complexation reactions and one molecule of BBHMP and two molecules of NA react with two molecules of the Pd(II) ion.

Keywords: Nicotinamide, 4-bromo-2, 6-bis-hydroxymethyl-phenol, Pd(II), spectral analysis, synthesis.

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684 Fabrication and Study of Nickel Phthalocyanine based Surface Type Capacitive Sensors

Authors: Mutabar Shah, Muhammad Hassan Sayyad, Khasan S. Karimov

Abstract:

Thin films of Nickel phthalocynine (NiPc) of different thicknesses (100, 150 and 200 nm) were deposited by thermal evaporator on glass substrates with preliminary deposited aluminum electrodes to form Al/NiPc/Al surface-type capacitive humidity sensors. The capacitance-humidity relationships of the sensors were investigated at humidity levels from 35 to 90% RH. It was observed that the capacitance value increases nonlinearly with increasing humidity level. All measurements were taken at room temperature.

Keywords: Capacitive sensor, Humidity, Nickel phthalocyanine, Organic semiconductor.

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683 Attenuation in Transferred RF Power to a Biomedical Implant due to the Absorption of Biological Tissue

Authors: Batel Noureddine, Mehenni Mohamed, Kouadik Smain

Abstract:

In a transcutanious inductive coupling of a biomedical implant, a new formula is given for the study of the Radio Frequency power attenuation by the biological tissue. The loss of the signal power is related to its interaction with the biological tissue and the composition of this one. A confrontation with the practical measurements done with a synthetic muscle into a Faraday cage, allowed a checking of the obtained theoretical results. The supply/data transfer systems used in the case of biomedical implants, can be well dimensioned by taking in account this type of power attenuation.

Keywords: Biological tissue, coupled coils, implanted device, power attenuation.

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682 Determination of Optical Constants of Semiconductor Thin Films by Ellipsometry

Authors: Aïssa Manallah, Mohamed Bouafia

Abstract:

Ellipsometry is an optical method based on the study of the behavior of polarized light. The light reflected on a surface induces a change in the polarization state which depends on the characteristics of the material (complex refractive index and thickness of the different layers constituting the device). The purpose of this work is to determine the optical properties of semiconductor thin films by ellipsometry. This paper describes the experimental aspects concerning the semiconductor samples, the SE400 ellipsometer principle, and the results obtained by direct measurements of ellipsometric parameters and modelling using appropriate software.

Keywords: Ellipsometry, optical constants, semiconductors, thin films.

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681 Crude Protein and Ash Content in Different Coloured Phaseolus coccineus L.

Authors: Liene Strauta, Sandra Muizniece-Brasava, Ina Alsina

Abstract:

Phaseolus coccineus L. is the third most important cultivated Phaseolus species in the world. It is widely grown in Latvia due to its earliness, good taste and uniform and qualitative yield. Experiments were carried out in the laboratories of Department of Food Technology and Agronomical Analysis Scientific Laboratory at Latvia Universityof Agriculture. Beans (Phaseolus coccineus L.) crude protein, crude ash content as well as colour measurements were analyzed. Results show, that brown coloured beans have less crude protein content than others, and ash content have significant differences.

Keywords: Phaseoluscoccineus, protein, ash, colour.

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680 Edge Detection with the Parametric Filtering Method (Comparison with Canny Method)

Authors: Yacine Ait Ali Yahia, Abderazak Guessoum

Abstract:

In this paper, a new method of image edge-detection and characterization is presented. “Parametric Filtering method" uses a judicious defined filter, which preserves the signal correlation structure as input in the autocorrelation of the output. This leads, showing the evolution of the image correlation structure as well as various distortion measures which quantify the deviation between two zones of the signal (the two Hamming signals) for the protection of an image edge.

Keywords: Edge detection, parametrable recursive filter, autocorrelation structure, distortion measurements.

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679 Velocity Distribution in Open Channels with Sand: An Experimental Study

Authors: E. Keramaris

Abstract:

In this study, laboratory experiments in open channel flows over a sand bed were conducted. A porous bed (sand bed) with porosity of ε=0.70 and porous thickness of s΄=3 cm was tested. Vertical distributions of velocity were evaluated by using a two-dimensional (2D) Particle Image Velocimetry (PIV). Velocity profiles are measured above the impermeable bed and above the sand bed for the same different total water heights (h= 6, 8, 10 and 12 cm) and for the same slope S=1.5. Measurements of mean velocity indicate the effects of the bed material used (sand bed) on the flow characteristics (Velocity distribution and Reynolds number) in comparison with those above the impermeable bed.

Keywords: Particle image velocimetry, sand bed, velocity distribution, Reynolds number.

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678 Evaluation of Droplet Sizes from Video Images for Metal Working Fluids

Authors: R. Hacıoğlu, A. Genç, B. Bakırcı

Abstract:

Metal working fluids were used in the preparation of oil in water emulsions. The size of oil droplets were evaluated by using the analysis of video images taken from the zeta potential measurements. The evaluated size distributions for emulsions were also tested by microscopic analysis. In addition, emulsion stabilities were discussed depending on electrolyte concentration and pH. The results showed that the stability of oil emulsions was strongly related to pH and the concentration of CaCl2. However, the same dependency was not observed for NaCl.

Keywords: Droplet size distribution, emulsion stability, o/w emulsions, video images.

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677 Cryptocurrency-Based Mobile Payments with Near-Field Communication-Enabled Devices

Authors: Marko Niinimaki

Abstract:

Cryptocurrencies are getting increasingly popular, but very few of them can be conveniently used in daily mobile phone purchases. To solve this problem, we demonstrate how to build a functional prototype of a mobile cryptocurrency-based e-commerce application the communicates with Near-Field Communication (NFC) tags. Using the system, users are able to purchase physical items with an NFC tag that contains an e-commerce URL. The payment is done simply by touching the tag with a mobile device and accepting the payment. Our method is constructive: we describe the design and technologies used in the implementation and evaluate the security and performance of the solution. Our main finding is that the analysis and measurements show that our solution is feasible for e-commerce.

Keywords: Cryptocurrency, e-commerce, NFC, mobile devices.

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676 The Effect of Ageing on Impact Toughness and Microstructure of 2024 Al-Cu-Mg Alloy

Authors: Swami Naidu Gurugubelli

Abstract:

The present study aims at determining the effect of ageing on the impact toughness and microstructure of 2024 Al-Cu - Mg alloy. Following the 2 h solutionizing treatment at 450°C and water quench, the specimens were aged at 200°C for various periods (1 to 18 h). The precipitation stages during ageing were monitored by hardness measurements. For each specimen group, Charpy impact and hardness tests were carried out. During ageing the impact toughness of the alloy first increased, and then, following a maxima decreased due to the precipitation of intermediate phases, finally it reached its minimum at the peak hardness. Correlations between hardness and impact toughness were investigated.

Keywords: Ageing, alloy, hardness, microstructure.

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675 Investigation and Evalution of Swelling Kinetics Related to Biocopolymers Based on CMC poly(AA-co BuMC)

Authors: Mohammad Sadeghi, Behrouz Heidari, Korush Montazeri

Abstract:

In this paper, we have focused on study of swelling kinetics and salt-sensitivity behavior of a superabsorbing hydrogel based on carboxymethylcellulose (CMC) and acrylic acid and 2- Buthyl methacrylate. The swelling kinetics of the hydrogels with various particle sizes was preliminary investigated as well. The swelling of the hydrogel showed a second order kinetics of swelling in water. In addition, swelling measurements of the synthesized hydrogels in various chloride salt solutions was measured. Results indicated that a swelling-loss with an increase in the ionic strength of the salt solutions.

Keywords: Carboxymethylcellulose, swelling kinetics, 2-hydroxypropylmetacrylate, acrylic acid.

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674 Experimental Validation of the Predicted Performance of a Wind Driven Venturi Ventilator

Authors: M. A. Serag-Eldin

Abstract:

The paper presents the results of simple measurements conducted on a model of a wind-driven venturi-type room ventilator. The ventilator design is new and was developed employing mathematical modeling. However, the computational model was not validated experimentally for the particular application considered. The paper presents the performance of the ventilator model under laboratory conditions, for five different wind tunnel speeds. The results are used to both demonstrate the effectiveness of the new design and to validate the computational model employed to develop it.

Keywords: Venturi-flow, ventilation, Wind-energy, Wind flow.

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673 Hardware Centric Machine Vision for High Precision Center of Gravity Calculation

Authors: Xin Cheng, Benny Thörnberg, Abdul Waheed Malik, Najeem Lawal

Abstract:

We present a hardware oriented method for real-time measurements of object-s position in video. The targeted application area is light spots used as references for robotic navigation. Different algorithms for dynamic thresholding are explored in combination with component labeling and Center Of Gravity (COG) for highest possible precision versus Signal-to-Noise Ratio (SNR). This method was developed with a low hardware cost in focus having only one convolution operation required for preprocessing of data.

Keywords: Dynamic thresholding, segmentation, position measurement, sub-pixel precision, center of gravity.

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672 FEM Analysis of Occluded Ear Simulator with Narrow Slit Pathway

Authors: M. Sasajima, T. Yamaguchi, M. Watanabe, Y. Koike

Abstract:

This paper discusses the propagation of sound waves in air, specifically in narrow rectangular pathways of an occluded-ear simulator for acoustic measurements. In narrow pathways, both the speed of sound and the phase of the sound waves are affected by the damping of the air viscosity. Herein, we propose a new finite-element method (FEM) that considers the effects of the air viscosity. The method was developed as an extension of existing FEMs for porous, sound-absorbing materials. The results of a numerical calculation for a three-dimensional ear-simulator model using the proposed FEM were validated by comparing with theoretical lumped-parameter modeling analysis and standard values.

Keywords: Ear simulator, FEM, simulation, viscosity.

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671 Control of Pressure Gradient in the Contraction of a Wind Tunnel

Authors: Dehghan Manshadi M., Mirzaei M., Soltani M. R., Ghorbanian K.

Abstract:

Subsonic wind tunnel experiments were conducted to study the effect of tripped boundary layer on the pressure distribution in the contraction region of the tunnel. Measurements were performed by installing trip strip at two different positions in the concave portion of the contraction. The results show that installation of the trip strips, have significant effects on both turbulence and pressure distribution. The reduction in the free stream turbulence and reduction of the wall static pressure distribution deferred signified with the location of the trip strip.

Keywords: Contraction, pressure distribution, trip strip, turbulence intensity.

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670 Behavior Evaluation of an Anchored Wall

Authors: Polo G. Yohn Edison, Rocha F. Pedricto

Abstract:

This work presents a study about a retaining structure designed for the duplication of the rail FEPASA on the 74th km between Santos and São Paulo. This structure, an anchored retaining wall, was instrumented in the anchors heads with strain gauges in order to monitor its loads. The load measurements occurred during the performance test, locking and also after the works were concluded. A decrease on anchors loads is noticed at the moment immediately after the locking, during construction and after the works finished. It was observed that a loss of load in the anchors occurred to a maximum of 54%.

Keywords: Anchors, Instrumentation, Retaining wall, Strain gauges.

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669 Coherent and Incoherent Scattering Cross Sections for Elements with 13

Authors: Panakkada Latha, K. K. Abdullah, M. P. Unnikrishnan, K. M. Varier, B. R. S. Babu

Abstract:

Coherent and incoherent scattering cross section measurements have been carried out using a HPGe detector on elements in the range of Z = 13 - 50 using 241Am gamma rays. The cross sections have been derived by comparing the net count rate obtained from the Compton peak of aluminium with the corresponding peak of the target. The measured cross sections for the coherent and incoherent processes are compared with theoretical values and earlier reported values. Our results are in agreement with the theoretical values.

Keywords: Cross section, coherent scattering, incoherent scattering, 241Am.

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