Search results for: circumference-width and depth measurements

Authors: N. Dahbi, D. E. Arafah

Abstract:

Cd1−xZnxS thins films have been fabricated from ZnS/CdS/ZnS multilayer thin film systems, by using the vacuum deposition method; the Rutherford back-scattering (RBS) technique have been applied in order to determine the: structure, composition, depth profile, and stoichiometric of these films. The influence of the chemical and heat treatments on the produced films also have been investigated; the RBS spectra of the films showed that homogenous Cd1−xZnxS can be synthesized with x=0.45.

Keywords: Cd1−xZnxS, chemical treatment, depth profile, heat treatment, RBS, RUMP simulation, thin film, vacuum deposition, ZnS/CdS/ZnS

Procedia PDF Downloads 197

Authors: Mazen Al-Bulaihed, Nissar Wani, Abdulrahman Al-Arainy, Yasin Khan

Abstract:

Partial Discharge (PD) measurements are widely used for diagnostic purposes in electrical equipment used in power systems. The main cause of these measurements is to prevent large power failures as cables are prone to aging, which usually results in embrittlement, cracking and eventual failure of the insulating and sheathing materials, exposing the conductor and risking a potential short circuit, a likely cause of the electrical fire. Many distribution networks rely heavily on medium voltage (MV) power cables. The presence of joints in these networks is a vital part of serving the consumer demand for electricity continuously. Such measurements become even more important when the extent of dependence increases. Moreover, it is known that the partial discharge in joints and termination are difficult to track and are the most crucial point of failures in large power systems. This paper discusses the diagnostic techniques of four samples of XLPE insulated cable joints, each included with a different type of defect. Experiments were carried out by measuring PD and tanδ at very low frequency applied high voltage. The results show the importance of combining PD and tanδ for effective cable assessment.

Keywords: partial discharge, tan delta, very low frequency, XLPE cable

Procedia PDF Downloads 124

Authors: Justice Zakhele Msomi

Abstract:

Nanoparticles of CdFe2O4 with particle size of about 10 nm have been synthesized by high energy ball milling and co-precipitation processes. The synthesis route appears to have some effects on the properties. The compounds have been characterized by X-ray diffraction, Fourier Transform Infrared (FTIR), transmission electron microscopy (TEM), Mössbauer and magnetization measurements. The XRD pattern of CdFe2O4 provides information about single-phase formation of spinel structure with cubic symmetry. The FTIR measurements between 400 and 4000 cm-1 indicate intrinsic cation vibration of the spinel structure. The Mössbauer spectra were recorded at 4 K and 300 K. The hyperfine fields appear to be highly sensitive on particle size. The evolution of the properties as a function of particle size is also presented.

Keywords: ferrite, nanoparticles, magnetization, Mössbauer

Procedia PDF Downloads 365

Authors: I. C. Cho, W. H. Wen, H. Y. Tsai, T. C. Chao, C. J. Tung

Abstract:

Tissue-equivalent proportional counter (TEPC) is a useful instrument used to measure radiation single-event energy depositions in a subcellular target volume. The quantity of measurements is the microdosimetric lineal energy, which determines the relative biological effectiveness, RBE, for radiation therapy or the radiation-weighting factor, WR, for radiation protection. TEPC is generally used in a mixed radiation field, where each component radiation has its own RBE or WR value. To reduce the pile-up effect during radiotherapy measurements, a miniature TEPC (mini TEPC) with cavity size in the order of 1 mm may be required. In the present work, a homemade mini TEPC with a cylindrical cavity of 1 mm in both the diameter and the height was constructed to measure the lineal energy spectrum of a mixed radiation field with high- and low-LET radiations. Instead of using external radiation beams to penetrate the detector wall, mixed radiation fields were produced by the interactions of neutrons with TEPC walls that contained small plugs of different materials, i.e. Li, B, A150, Cd and N. In all measurements, mini TEPC was placed at the beam port of the Tsing Hua Open-pool Reactor (THOR). Measurements were performed using the propane-based tissue-equivalent gas mixture, i.e. 55% C3H8, 39.6% CO2 and 5.4% N2 by partial pressures. The gas pressure of 422 torr was applied for the simulation of a 1 m diameter biological site. The calibration of mini TEPC was performed using two marking points in the lineal energy spectrum, i.e. proton edge and electron edge. Measured spectra revealed high lineal energy (> 100 keV/m) peaks due to neutron-capture products, medium lineal energy (10 – 100 keV/m) peaks from hydrogen-recoil protons, and low lineal energy (< 10 keV/m) peaks of reactor photons. For cases of Li and B plugs, the high lineal energy peaks were quite prominent. The medium lineal energy peaks were in the decreasing order of Li, Cd, N, A150, and B. The low lineal energy peaks were smaller compared to other peaks. This study demonstrated that internally produced mixed radiations from the interactions of neutrons with different plugs in the TEPC wall provided a useful approach for TEPC measurements of lineal energies.

Keywords: TEPC, lineal energy, microdosimetry, radiation quality

Procedia PDF Downloads 447

Authors: Sahabeh Safarpour, Khiruddin Abdullah, Hwee San Lim, Mohsen Dadras

Abstract:

Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters are important due to health impact. One widely available metric of aerosol abundance is the aerosol optical depth (AOD). The AOD is the integrated light extinction coefficient over a vertical atmospheric column of unit cross section, which represents the extent to which the aerosols in that vertical profile prevent the transmission of light by absorption or scattering. Seasonal aerosol optical depth (AOD) values at 550 nm derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA’s Terra satellites, for the 10 years period of 2000-2010 were used to test 7 different spatial interpolation methods in the present study. The accuracy of estimations was assessed through visual analysis as well as independent validation based on basic statistics, such as root mean square error (RMSE) and correlation coefficient. Based on the RMSE and R values of predictions made using measured values from 2000 to 2010, Radial Basis Functions (RBFs) yielded the best results for spring, summer, and winter and ordinary kriging yielded the best results for fall.

Keywords: aerosol optical depth, MODIS, spatial interpolation techniques, Radial Basis Functions

Procedia PDF Downloads 376

Authors: Henrique Fernandes, Sofia Catalucci, Richard Leach, Kapil Sugand

Abstract:

Background: Holograms are 3D images formed by the interference of light beams from a laser or other coherent light source. Pepper’s ghost is a form of hologram conceptualised in the 18th century. This Holographic visualisation with metrology measuring techniques by displaying measurements taken in real-time in holographic form can assist in research and education. New structural designs such as the Plexiglass Stand and the Hologram Box can optimise the holographic experience. Method: The equipment used included: (i) Zeiss’s ATOS Core 300 optical coordinate measuring instrument that scanned real-world objects; (ii) Cloud Compare, open-source software used for point cloud processing; and (iii) Hologram Box, designed and manufactured during this research to provide the blackout environment needed to display 3D point clouds in real-time measurements in holographic format, in addition to a portability aspect to holograms. The equipment was tailored to realise the goal of displaying measurements in an innovative technique and to improve on conventional methods. Three test scans were completed before doing a holographic conversion. Results: The outcome was a precise recreation of the original object in the holographic form presented with dense point clouds and surface density features in a colour map. Conclusion: This work establishes a way to visualise data in a point cloud system. To our understanding, this is a work that has never been attempted. This achievement provides an advancement in holographic visualisation. The Hologram Box could be used as a feedback tool for measurement quality control and verification in future smart factories.

Keywords: holography, 3D scans, hologram box, metrology, point cloud

Procedia PDF Downloads 55

Authors: Seyed Abolhassan Naeini, Hamed Yekehdehghan

Abstract:

One of the factors that affect the constructions adjacent to a slope is stability. There are various methods for the stability of the slopes, one of which is the use of concrete group piles. This study, using FLAC3D software, has tried to investigate the changes in safety coefficient because of the use of concrete group piles. In this research, furthermore, the optimal position of the piles has been investigated and the results show that the group pile does not affect the toe of the slope. In addition, the effect of the piles' burial depth on the slope has been studied. Results show that by increasing the piles burial depth on a slope, the level of stability and as a result the safety coefficient increases. In the investigation of reducing the distance between the piles and increasing the depth of underground water, it was observed that the obtained safety coefficient increased. Finally, the effect of the resistance of the lower stabilizing layer of the slope on stabilization was investigated by the pile group. The results showed that due to the behavior of the pile as a deep foundation, the stronger the soil layers are in the stable part of a stronger slope (in terms of resistance parameters), the more influential the piles are in enhancing the coefficient of safety.

Keywords: safety coefficient, group pile, slope, stability, FLAC3D software

Procedia PDF Downloads 65

Authors: M. Abbasi

Abstract:

A spillway structure is used to pass excess water and floods from upstream or upstream to downstream or tributary. The spillway is considered one of the most key members of the dam, and the failure of many dams is attributed to the inefficiency of their spillway. Weirs should be selected as strong, reliable and high-performance structures, and weirs should be ready for use in all conditions and able to drain the flood so that we do not witness many casualties and financial losses when a flood occurs. The purpose of this study is to simulate the flow pattern passing over the peak spillway in order to optimize and adjust the height of the spillway walls. In this research, the effect of the shape of the side wings on the flow pattern over the peak spillways of the Gotvand reservoir dam was simulated and modelled using Flow3D software. In this research, side wings with rounded walls with six different approach angles were used. In addition, the different value of H/Hd was used to check the effect of the tank head. The results showed that with the constant H/Hd ratio and the increase of the approach angle of the side wing, the flow depth first decreases and then increases. These changes were the opposite regarding the depth average speed of the flow and the depth average concentration of the air entering the flow. At the same time, with the constant angle of approach of the side wing and with the increase of H/Hd ratio, the flow depth increases. In general, a correct understanding of the operation of overflows and a correct design can significantly reduce construction costs and solve flooding problems.

Keywords: effect of the shape, gotvand reservoir dam, narrowing coefficients, supports of the gates

Procedia PDF Downloads 33

Authors: Setareh Gorji Ghalamestani, Lieven Vandevelde, Jan Melkebeek

Abstract:

In this work, an experimental technique is applied for the measurements of the vibrations and deformation of a test transformer core. Since the grid voltage contains some higher harmonics, in addition to a purely sinusoidal magnetisation of the core the presence of third harmonic is also studied. The vibrations of the transformer core for points as well as the surface scan of the leg show more deformation in the corners of the leg than the middle of the leg. The influence of the higher harmonic of the magnetisation on the core deformation is also more significant in the corners of the leg. The core deformation shape under a sinusoidal magnetisation with a higher harmonic is more wavy and fluctuating than that under a purely sinusoidal magnetisation.

Keywords: vibrations and noise, transformer, vibration measurements, laser vibrometer, higher harmonic

Procedia PDF Downloads 334

Authors: A. Gopala Krishna, M. Lakshmi Chaitanya, V. Kalyana Manohar

Abstract:

In the existent analysis, laser micro machining (LMM) of Silicon carbide (SiCp) reinforced Aluminum 7075 Metal Matrix Composite (Al7075/SiCp MMC) was studied. While machining, Because of the intense heat generated, A layer gets formed on the work piece surface which is called recast layer and this layer is detrimental to the surface quality of the component. The recast layer needs to be as small as possible for precise applications. Therefore, The height of recast layer and the depth of groove which are conflicting in nature were considered as the significant manufacturing criteria, Which determines the pursuit of a machining process obtained in LMM of Al7075/10%SiCp composite. The present work formulates the depth of groove and height of recast layer in relation to the machining parameters using the Response Surface Methodology (RSM) and correspondingly, The formulated mathematical models were put to use for optimization. Since the effect of machining parameters on the depth of groove and height of recast layer was contradictory, The problem was explicated as a multi objective optimization problem. Moreover, An evolutionary Non-dominated sorting genetic algorithm (NSGA-II) was employed to optimize the model established by RSM. Subsequently this algorithm was also adapted to achieve the Pareto optimal set of solutions that provide a detailed illustration for making the optimal solutions. Eventually experiments were conducted to affirm the results obtained from RSM and NSGA-II.

Keywords: Laser Micro Machining (LMM), depth of groove, Height of recast layer, Response Surface Methodology (RSM), non-dominated sorting genetic algorithm

Procedia PDF Downloads 322

Authors: Jalal Fazli Amiri, Mohammad Hossein Shahir, Mohammad Hossein Nemati, Afshin Heidarinia

Abstract:

The current study was performed to investigate the effects of arginine, threonine, and glutamine supplementation in excess of requirements in the starter period (17 days) on performance, intestinal morphology, and immune response of broilers. Four hundred and sixteen male day-old chicks were assigned in a 2×2×2 factorial arrangement to a completely randomized design with four replicates (13 birds per replicate ). Treatments were: a control group that received the basal diet, basal diet plus 1% glutamine, basal diet plus 0.2% threonine, basal diet plus 0.75 % arginine, and combination of these three amino acids (glutamine+arginine, glutamine+threonine, arginine+threonine and arginine+ glutamine+threonine). The effect of glutamine supplementation on feed intake was significant in week 4 (p < 0.05), week 6 (p < 0.001), and total feed intake (p < 0.05) and caused declined feed intake. No significant differences of glutamine addition were observed on intestinal morphology (villi height, crypt depth, villi height to crypt depth ratio, villi width). Threonine supplementation caused increased weight gain in week 2 (p < 0.001) and 3 and a decrease of total feed intake (p < 0.05). Duodenum and jejunum villi height, crypt depth, villi height to crypt depth ratio, villi width were not affected. The effect of arginine supplementation was the increase of breast percentage (p < 0.05) and a decrease of jejunum villi high (p < 0.05) and Jejunum crypt depth (p < 0.05). Supplementation of arginine, threonine, and glutamine had no significant effects on blood titer of antibodies against Newcastle disease, infectious bronchitis, avian influenza. Overall, it seems that the supplementation of arginine, threonine, and glutamine in excess of requirements in the starter period had no effect on performance in subsequent periods and intestinal morphology.

Keywords: intestinal morphology, immunity, broiler chickens, glutamine, arginine, threonine

Procedia PDF Downloads 105

Authors: Ebru Turgal, Beyza Doganay Erdogan

Abstract:

Machine learning aims to model the relationship between the response and features. Medical decision-making researchers would like to make decisions about patients’ course and treatment, by examining the repeated measurements over time. Boosting approach is now being used in machine learning area for these aims as an influential tool. The aim of this study is to show the usage of multivariate tree boosting in this field. The main reason for utilizing this approach in the field of decision-making is the ease solutions of complex relationships. To show how multivariate tree boosting method can be used to identify important features and feature-time interaction, we used the data, which was collected retrospectively from Ankara University Chest Diseases Department records. Dataset includes repeated PF ratio measurements. The follow-up time is planned for 120 hours. A set of different models is tested. In conclusion, main idea of classification with weighed combination of classifiers is a reliable method which was shown with simulations several times. Furthermore, time varying variables will be taken into consideration within this concept and it could be possible to make accurate decisions about regression and survival problems.

Keywords: boosted multivariate trees, longitudinal data, multivariate regression tree, panel data

Procedia PDF Downloads 171

Authors: C. Han, H. Kim, S. Park

Abstract:

The purpose of the present study is to analyze the effect of surface roughness on fatigue life of SCM440 steel. Two groups of specimens were made from SCM440 steel with and without surface polished after forging process and resulted in different values of surface roughness. The difference of the surface roughness between two groups was clearly distinguished even to the naked eye. Surface roughness of both groups of the specimens was quantitatively measured by a roughness measuring device, Talysurf series2 (Taylor-Hobson Co., USA). Average roughness (Ra) and maximum roughness depth (Rmax) values were obtained by scanning 45 mm with a speed of 0.25 mm/s. Fatigue tests were conducted using a three-point bending method with a cyclic sinusoidal profile of 5 Hz, stress ratio of R = 0.1 and reference life for fatigue limit of 1 × 106 cycles. Ra and Rmax without surface polished were 10.497 ± 1.721 μm and 87.936 ± 16.210 μm, respectively while those values with surface polished were much smaller (ongoing measurements). Fatigue lives of the surface-polished specimens achieved approximately 1 × 106 cycles under the maximum stress of 900 MPa, which was 10 times longer than those of the surface-untreated specimens with an average roughness of 10.082 μm. The results showed that an increase in surface roughness values led to a decrease in fatigue lives.

Keywords: surface roughness, fatigue test, fatigue life, SCM440 steel

Procedia PDF Downloads 315

Authors: L. N. Shubha, P. Madhusudana Rao

Abstract:

The Polyaniline / Copper Oxide(PANI / CuO) nanocomposite was prepared by solution mixing of prepared Polyaniline and copper Oxide in Dimethyl sulfoxide (DMSO). The synthesis involved the formation of dark green colored Polyaniline-Copper Oxide nanocomposite. The synthesized polymer nano composites were characterized by XRD, FTIR, SEM and UV-Visible Spectroscopy. The characteristic peaks in XRD, FTIR and UV-Visible spectra confirmed the presence of CuO in the polymer structure. SEM analysis revealed formation of PANI/CuO nano composite The D.C. conductivity measurements were performed using two probe method for various temperatures.

Keywords: polyaniline/copper oxide (PANI/CuO) nanocomposite, XRD, SEM, FTIRand DC- conductivity, UV-visible spectra

Procedia PDF Downloads 267

Authors: M. S. Said, J. A. Ghani, C. H. Che Hassan, N. N. Wan, M. A. Selamat, R. Othman

Abstract:

Metal Matrix Composite (MMCs) have attracted considerable attention as a result of their ability to provide high strength, high modulus, high toughness, high impact properties, improved wear resistance and good corrosion resistance than unreinforced alloy. Aluminium Silicon (Al/Si) alloys Metal Matrix composite (MMC) has been widely used in various industrial sectors such as transportation, domestic equipment, aerospace, military, construction, etc. Aluminium silicon alloy is MMC reinforced with aluminium nitride (AlN) particle and becomes a new generation material for automotive and aerospace applications. The AlN material is one of the advanced materials with light weight, high strength, high hardness and stiffness qualities which have good future prospects. However, the high degree of ceramic particles reinforcement and the irregular nature of the particles along the matrix material that contribute to its low density, is the main problem that leads to the machining difficulties. This paper examines tool wear when milling AlSi/AlN Metal Matrix Composite using a TiB2 coated carbide cutting tool. The volume of the AlN reinforced particle was 10%. The milling process was carried out under dry cutting condition. The TiB2 coated carbide insert parameters used were the cutting speed of (230 m/min, feed rate 0.4mm tooth, DOC 0.5mm, 300 m/min, feed rate 0.8mm/tooth, DOC 0.5mm and 370 m/min, feed rate 0.8, DOC 0.4m). The Sometech SV-35 video microscope system was used for tool wear measurements respectively. The results have revealed that the tool life increases with the cutting speed (370 m/min, feed rate 0.8 mm/tooth and depth of cut 0.4mm) constituted the optimum condition for longer tool life which is 123.2 min. While at medium cutting speed, it is found that the cutting speed of 300m/min, feed rate 0.8 mm/tooth and depth of cut 0.5mm only 119.86 min for tool wear mean while the low cutting speed give 119.66 min. The high cutting speed gives the best parameter for cutting AlSi/AlN MMCs materials. The result will help manufacture to machining the AlSi/AlN MMCs materials.

Keywords: AlSi/AlN Metal Matrix Composite milling process, tool wear, TiB2 coated carbide tool, manufacturing engineering

Procedia PDF Downloads 398

Authors: Hatice Guzel, Imran Oral, Huseyin Isler

Abstract:

In this study, elastic constants, Young’s modulus, Poisson’s ratios, and shear moduli of orthotropic composite materials, consisting of E-glass/epoxy and carbon/epoxy, were calculated by ultrasonic velocities which were measured using ultrasonic pulse-echo method. 35 MHz computer controlled analyzer, 60 MHz digital oscilloscope, 5 MHz longitudinal probe, and 2,25 MHz transverse probe were used for the measurements of ultrasound velocities, the measurements were performed at ambient temperature. It was understood from the data obtained in this study that, measured ultrasound velocities and the calculated elasticity coefficients were depending on the fiber orientations.

Keywords: composite materials, elastic constants, orthotropic materials, ultrasound

Procedia PDF Downloads 258

Authors: Mostafa Shahriari, Sergio Rojas, David Pardo, Angel Rodriguez- Rozas, Shaaban A. Bakr, Victor M. Calo, Ignacio Muga

Abstract:

Logging-While Drilling (LWD) is a technique to record down-hole logging measurements while drilling the well. Nowadays, LWD devices (e.g., nuclear, sonic, resistivity) are mostly used commercially for geo-steering applications. Modern borehole resistivity tools are able to measure all components of the magnetic field by incorporating tilted coils. The depth of investigation of LWD tools is limited compared to the thickness of the geological layers. Thus, it is a common practice to approximate the Earth’s subsurface with a sequence of 1D models. For a 1D model, we can reduce the dimensionality of the problem using a Hankel transform. We can solve the resulting system of ordinary differential equations (ODEs) either (a) analytically, which results in a so-called semi-analytic method after performing a numerical inverse Hankel transform, or (b) numerically. Semi-analytic methods are used by the industry due to their high performance. However, they have major limitations, namely: -The analytical solution of the aforementioned system of ODEs exists only for piecewise constant resistivity distributions. For arbitrary resistivity distributions, the solution of the system of ODEs is unknown by today’s knowledge. -In geo-steering, we need to solve inverse problems with respect to the inversion variables (e.g., the constant resistivity value of each layer and bed boundary positions) using a gradient-based inversion method. Thus, we need to compute the corresponding derivatives. However, the analytical derivatives of cross-bedded formation and the analytical derivatives with respect to the bed boundary positions have not been published to the best of our knowledge. The main contribution of this work is to overcome the aforementioned limitations of semi-analytic methods by solving each 1D model (associated with each Hankel mode) using an efficient multi-scale finite element method. The main idea is to divide our computations into two parts: (a) offline computations, which are independent of the tool positions and we precompute only once and use them for all logging positions, and (b) online computations, which depend upon the logging position. With the above method, (a) we can consider arbitrary resistivity distributions along the 1D model, and (b) we can easily and rapidly compute the derivatives with respect to any inversion variable at a negligible additional cost by using an adjoint state formulation. Although the proposed method is slower than semi-analytic methods, its computational efficiency is still high. In the presentation, we shall derive the mathematical variational formulation, describe the proposed multi-scale finite element method, and verify the accuracy and efficiency of our method by performing a wide range of numerical experiments and comparing the numerical solutions to semi-analytic ones when the latest are available.

Keywords: logging-While-Drilling, resistivity measurements, multi-scale finite elements, Hankel transform

Procedia PDF Downloads 357

Authors: Neveen AlQasas, Daniel Johnson

Abstract:

Membranes for water treatment are an established technology that attracts great attention due to its simplicity and cost effectiveness. However, membranes in operation suffer from the adverse effect of membrane fouling. Bio-fouling is a phenomenon that occurs at the water-membrane interface, and is a dynamic process that is initiated by the adsorption of dissolved organic material, including biomacromolecules, on the membrane surface. After initiation, attachment of microorganisms occurs, followed by biofilm growth. The biofilm blocks the pores of the membrane and consequently results in reducing the water flux. Moreover, the presence of a fouling layer can have a substantial impact on the membrane separation properties. Understanding the mechanism of the initiation phase of biofouling is a key point in eliminating the biofouling on membrane surfaces. The adhesion and attachment of different fouling materials is affected by the surface properties of the membrane materials. Therefore, surface properties of different polymeric materials had been studied in terms of their surface energies and Hansen solubility parameters (HSP). The difference between the combined HSP parameters (HSP distance) allows prediction of the affinity of two materials to each other. The possibilities of measuring the HSP of different polymer films via surface measurements, such as contact angle has been thoroughly investigated. Knowing the HSP of a membrane material and the HSP of a specific foulant, facilitate the estimation of the HSP distance between the two, and therefore the strength of attachment to the surface. Contact angle measurements using fourteen different solvents on five different polymeric films were carried out using the sessile drop method. Solvents were ranked as good or bad solvents using different ranking method and ranking was used to calculate the HSP of each polymeric film. Results clearly indicate the absence of a direct relation between contact angle values of each film and the HSP distance between each polymer film and the solvents used. Therefore, estimating HSP via contact angle alone is not sufficient. However, it was found if the surface tensions and viscosities of the used solvents are taken in to the account in the analysis of the contact angle values, a prediction of the HSP from contact angle measurements is possible. This was carried out via training of a neural network model. The trained neural network model has three inputs, contact angle value, surface tension and viscosity of solvent used. The model is able to predict the HSP distance between the used solvent and the tested polymer (material). The HSP distance prediction is further used to estimate the total and individual HSP parameters of each tested material. The results showed an accuracy of about 90% for all the five studied films

Keywords: surface characterization, hansen solubility parameter estimation, contact angle measurements, artificial neural network model, surface measurements

Procedia PDF Downloads 57

Authors: Thomas Prevenslik

Abstract:

Weakly Interacting Massive Particle (WIMP) experiments suggesting dark matter does not exist are consistent with the argument that the long-standing galaxy rotation problem may be resolved without the need for dark matter if the redshift measurements giving the higher than expected galaxy velocities are corrected for the redshift in cosmic dust. Because of the ubiquity of cosmic dust, all velocity measurements in astronomy based on redshift are most likely overstated, e.g., an accelerating Universe expansion need not exist if data showing supernovae brighter than expected based on the redshift/distance relation is corrected for the redshift in dust. Extensions of redshift corrections for cosmic dust to other historical astronomical observations are briefly discussed.

Keywords: alternative theories, cosmic dust redshift, doppler effect, quantum mechanics, quantum electrodynamics

Procedia PDF Downloads 272

Authors: Suneel Kumar, Nanda Kumar J. Sreelal Sreedhar, Suchibrata Sen, V. Muralidharan,

Abstract:

Fan technology is very critical and crucial for any aero engine technology. The fan disc forms a critical part of the fan module. It is an airworthiness requirement to have a metrological qualified quality disc. The current study uses a tactile probing and scanning on an articulated measuring machine (AMM), a bridge type coordinate measuring machine (CMM) and Metrology software for intermediate and final dimensional and geometrical verification during the prototype development of the disc manufactured through forging and machining process. The circumferential dovetails manufactured through the milling process are evaluated based on the evaluated and analysed metrological process. To perform metrological optimization a change of philosophy is needed making quality measurements available as fast as possible to improve process knowledge and accelerate the process but with accuracy, precise and traceable measurements. The offline CMM programming for inspection and optimisation of the CMM inspection plan are crucial portions of the study and discussed. The dimensional measurement plan as per the ASME B 89.7.2 standard to reach an optimised CMM measurement plan and strategy are an important requirement. The probing strategy, stylus configuration, and approximation strategy effects on the measurements of circumferential dovetail measurements of the developmental prototype disc are discussed. The results were discussed in the form of enhancement of the R &R (repeatability and reproducibility) values with uncertainty levels within the desired limits. The findings from the measurement strategy adopted for disc dovetail evaluation and inspection time optimisation are discussed with the help of various analyses and graphical outputs obtained from the verification process.

Keywords: coordinate measuring machine, CMM, aero engine, articulated measuring machine, fan disc

Procedia PDF Downloads 82

Authors: Adewoyin O. Olusegun, Emmanuel O. Joshua, Marvel L. Akinyemi

Abstract:

The heterogeneous nature of the subsurface requires the use of factual information to deal with rather than assumptions or generalized equations. Therefore, there is need to determine the actual rate of settlement possible in the soil before structures are built on it. This information will help in determining the type of foundation design and the kind of reinforcement that will be necessary in constructions. This paper presents a simplified and a faster approach for determining foundation settlement in any type of soil using real field data acquired from seismic refraction techniques and cone penetration tests. This approach was also able to determine the depth of settlement of each strata of soil. The results obtained revealed the different settlement time and depth of settlement possible.

Keywords: heterogeneous, settlement, foundation, seismic, technique

Procedia PDF Downloads 405

Authors: Maria Konstadinou, Etienne Alderlieste, Anderson Peccin da Silva, Ben Arntz, Leonard van der Bijl, Wouter Verschueren

Abstract:

The shear strength and compression properties of stiff Boom clay from Belgium at the depth of about 30 m has been investigated by means of cone penetration and laboratory testing. The latter consisted of index classification, constant rate of strain, direct, simple shear, and unconfined compression tests. The Boom clay samples exhibited strong swelling tendencies. The suction pressure was measured via different procedures and has been compared to the expected in-situ stress. The undrained shear strength and OCR profile determined from CPTs is not compatible with the experimental measurements, which gave significantly lower values. The observed response can be attributed to the presence of pre-existing discontinuities, as shown in microscale CT scans of the samples. The results of this study demonstrate that the microstructure of the clay prior to testing has an impact on the mechanical behaviour and can cause inconsistencies in the comparison of the laboratory test results with in-situ data.

Keywords: boom clay, laboratory testing, overconsolidation ratio, stress-strain response, swelling, undrained shear strength

Procedia PDF Downloads 112

Authors: Mohamed Gomaa Mohamed

Abstract:

Background and purpose: Ideal posture involves a minimal amount of stress or strain on various body segments which are aligned and worked in harmony to protect the body from injury or progressive deformity. One of most common faulty posture encountered in clinical setting is forward head posture (FHP) that was considered one of the main predictors for neck pain. Furthermore, FHP may predispose to thoracic outlet syndrome, temporomandibular joint dysfunction, shoulder pain and headache. The large financial burden related to neck disorders management raises the need to improve the quality of assessment and rehabilitation of FHP. So, the purpose of the study is to compare between measurements of FHP as indicated with craniovertebral (CVA) and gaze angles assessed from dominant and non-dominant sides in football players who extensively use their dominant side and non-athletic subjects. Participants: Twenty-four subjects were divided into 12 football players and 12 non-athletic subjects. Methods: CVA and gaze angles were assessed through photogrammetric method. Photos were taken from dominant and non-dominant sides of the subjects while assuming standing position. Paired t-test was used to assess angles differences between dominant and non-dominant sides of the subjects. Since there were no statistical differences between CVA and gaze angles measured from dominant and non-dominant sides in each group, we pooled data together to become 24 measurements for each group (12 from dominant and 12 from non-dominant). Independent t-test was used to assess angles differences between football players and non-athletic subjects. Results: No significant differences were found between CVA and gaze angles measured from dominant and non-dominant sides of both groups (P>0.05). Also, there were no significant differences between CVA and gaze angles measured from football players and non-athletic subjects (P>0.05). Conclusion: FHP can be assessed from dominant or non-dominant sides interchangeably either in football players or non-athletic subjects. Furthermore, playing football has no impact on measurements of FHP when compared to non-athletic subjects.

Keywords: dominant side, forward head posture, football players, non-dominant side

Procedia PDF Downloads 222

Authors: Eseldin Keleb

Abstract:

In the pharmaceutical industry particle size distribution is an important parameter for the characterization of pharmaceutical powders. The powder flowability, reactivity and compatibility, which have a decisive impact on the final product, are determined by particle size and size distribution. Therefore, the aim of this study was to evaluate the influence of processing parameters on the particle size distribution measurements. Different Size fractions of α-lactose monohydrate and 5% polyvinylpyrrolidone were prepared by wet granulation and were used for the preparation of samples. The influence of sieve load (50, 100, 150, 200, 250, 300, and 350 g), processing time (5, 10, and 15 min), sample size ratios (high percentage of small and large particles), type of disturbances (vibration and shaking) and process reproducibility have been investigated. Results obtained showed that a sieve load of 50 g produce the best separation, a further increase in sample weight resulted in incomplete separation even after the extension of the processing time for 15 min. Performing sieving using vibration was rapider and more efficient than shaking. Meanwhile between day reproducibility showed that particle size distribution measurements are reproducible. However, for samples containing 70% fines or 70% large particles, which processed at optimized parameters, the incomplete separation was always observed. These results indicated that sieving reliability is highly influenced by the particle size distribution of the sample and care must be taken for samples with particle size distribution skewness.

Keywords: sieving, reliability, particle size distribution, processing parameters

Procedia PDF Downloads 577

Authors: Ismail Al-Yahmadi, Abbasher Gismelseed, Fatma Al-Mammari, Ahmed Al-Rawas, Ali Yousif, Imaddin Al-Omari, Hisham Widatallah, Mohamed Elzain

Abstract:

The influence of Fe-doping on the structural, magnetic and magnetocaloric properties of Nd₀.₆Sr₀.₄FeₓMn₁₋ₓO₃ (0≤ x ≤0.5) were investigated. The samples were synthesized by auto-combustion Sol-Gel method. The phase purity, crystallinity, and the structural properties for all prepared samples were examined by X-ray diffraction. XRD refinement indicates that the samples are crystallized in the orthorhombic single-phase with Pnma space group. Temperature dependence of magnetization measurements under a magnetic applied field of 0.02 T reveals that the samples with (x=0.0, 0.1, 0.2 and 0.3) exhibit a paramagnetic (PM) to ferromagnetic (FM) transition with decreasing temperature. The Curie temperature decreased with increasing Fe content from 256 K for x =0.0 to 80 K for x =0.3 due to increasing of antiferromagnetic superexchange (SE) interaction coupling. Moreover, the magnetization as a function of applied magnetic field (M-H) curves was measured at 2 K, and 300 K. the results of such measurements confirm the temperature dependence of magnetization measurements. The magnetic entropy change|∆SM | was evaluated using Maxwell's relation. The maximum values of the magnetic entropy change |-∆SMax |for x=0.0, 0.1, 0.2, 0.3 are found to be 15.35, 5.13, 3.36, 1.08 J/kg.K for an applied magnetic field of 9 T. Our result on magnetocaloric properties suggests that the parent sample Nd₀.₆Sr₀.₄MnO₃ could be a good refrigerant for low-temperature magnetic refrigeration.

Keywords: manganite perovskite, magnetocaloric effect, X-ray diffraction, relative cooling power

Procedia PDF Downloads 119

Authors: Nayif Alrasheedi, Sultan Almutairi

Abstract:

Field-wide, a water supply wells’ downhole corrosion inhibition program is being applied to maintain downhole component integrity and keep the fluid corrosivity below 5 MPY. Batch treatment is currently used to inject the oil field chemical. This work is a case study consisting of analytical procedures used to optimize the frequency of the good corrosion inhibition treatments. During the study, a corrosion cell was fitted with a special three-electrode configuration for electrochemical measurements, electrochemical linear polarization, corrosion monitoring, and microbial analysis. This study revealed that the current practice is not able to mitigate material corrosion in the downhole system for more than three months.

Keywords: downhole corrosion inhibition, electrochemical measurements, electrochemical linear polarization, corrosion monitoring

Procedia PDF Downloads 134

Authors: Yali Zheng, Peipei Luo, Shinan Chen, Jiasheng Hao, Hong Cheng

Abstract:

Most of traditional visual indoor navigation algorithms and methods only consider the localization in ordinary daytime, while we focus on the indoor re-localization in low light in the paper. As RGB images are degraded in low light, less discriminative infrared and depth image pairs are taken, as the input, by RGB-D cameras, the most similar candidates, as the output, are searched from databases which is built in the bag-of-word framework. Epipolar constraints can be used to relocalize the query infrared and depth image sequence. We evaluate our method in two datasets captured by Kinect2. The results demonstrate very promising re-localization results for indoor navigation system in low light environments.

Keywords: indoor navigation, low light, RGB-D camera, vision based

Procedia PDF Downloads 418

Authors: H. Li, W. Qin, Ben Ye

Abstract:

Friction Push Plug Welding (FPPW) is a solid phase welding suitable for repairing defective welds and filling self-reacting weld keyholes in Friction Stir Welds. In FPPW process, a tapered shaped plug is rotated at high speed and forced into a tapered hole in the substrate. The plug and substrate metal is softened by the increasing temperature generated by friction and material plastic deformation. This paper aims to investigate the effect of process parameters on the quality of the weld. Orthogonal design methods were employed to reduce the amount of experiment. Three values were selected for each process parameter, rotation speed (1500r/min, 2000r/min, 2500r/min), plunge depth (2mm, 3mm, 4mm) and plunge speed (60mm/min, 90mm/min, 120r/min). AA6061aluminum alloy plug and substrate plate was used in the experiment. In a trial test with the plunge depth of 1mm, a noticeable defect appeared due to the short plunge time and insufficient temperature. From the recorded temperature profiles, it was found that the peak temperature increased with the increase of the rotation speed, plunge speed and plunge depth. In the initial stage, the plunge speed was the main factor affecting heat generation, while in the steady state welding stage, the rotation speed played a more important role. The FPPW weld defect includes flash and incomplete penetration in the upper, middle and bottom interface with the substrate. To obtain defect free weld, the higher rotation speed and proper plunge depth were recommended.

Keywords: friction push plug welding, process parameter, weld defect, orthogonal design

Procedia PDF Downloads 117

Authors: Carolina Senabre, Sergio Valero, Emilio Velasco

Abstract:

This research objective is to compare the differences of brake measurements obtained with the same vehicle when braking on VTEQ Ministry of Transport (MOT) brake testers versus others such as Maha, Ryme and a dynamometric platform. These different types of brake testers have been used and analyzed by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University. Parameters of the vehicle have been controlled to be the same in all tests. Therefore, brake measurements variability will be due to the tester used. Advances and disadvantages of each brake tester have been analyzed.

Keywords: brake tester, Ministry of transport, longitudinal braking, Bank of Rollers

Procedia PDF Downloads 313

Authors: Rayan Elsiddig Eltaib, Yamanaka Norikazu, Mubarak Abdelrahman Abdalla

Abstract:

This study investigated the effects of Acacia Senegal, Calotropis procera, Leptadenia pyrotechnica, Ziziphus spina Christi, Balanites aegyptiaca, Indigofera oblongigolia, Arachis hypogea and Sesimum indicum grown in the western region of White Nile State on soil properties of the 0-10, 10-30, 30-60 and 60-90 cm depths. Soil properties were: pH(paste), electrical conductivity of the saturation extract (ECe), total N (TN), organic carbon (OC), soluble K, available P, aggregate stability and water holding capacity. Triplicate Soil samples were collected after the end of the rainy season using 5 cm diameter auger. Results indicated that pH, ECe and TN were not significantly different among plant cover types. In the top 10-30 cm depth, OC under all types was significantly higher than the control (4.1 to 7.7 fold). The highest (0.085%) OC was found under the Z. spina Christi and A. Senegal whereas the lowest (0.045%) was reported under the A. hypogea. In the 10-30 cm depth, with the exception of A. hypogea, Z. spina christi and S. indicum, P content was almost similar but significantly higher than the control by 72 to 129%. In the 10-30 cm depth, K content under the S. indicum (0.46 meq/L) was exceptionally high followed by Z. spina christi (0.102 meq/L) as compared to the control (0.029 meq/L). Water holding capacity and aggregate stability of the top 0-10 cm depth were not significantly different among plant cover types. Based on the fact that accumulation of organic matter in the soil profile of any ecosystem is an important indicator of soil quality, results of this study may conclude that (1) cultivation of A.senegal, B.aegyptiaca and Z. spina Christi improved soil quality whereas (2) cultivation of A. hypogea or soil that is solely invaded with C. procera and L.pyrotechnica may induce soil degradation.

Keywords: canopy, crops, shrubs, soil properties, trees

Procedia PDF Downloads 248