Search results for: ion acoustic wave
613 On the Hirota Bilinearization of Fokas-Lenells Equation to Obtain Bright N-Soliton Solution
Authors: Sagardeep Talukdar, Gautam Kumar Saharia, Riki Dutta, Sudipta Nandy
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In non-linear optics, the Fokas-Lenells equation (FLE) is a well-known integrable equation that describes how ultrashort pulses move across optical fiber. It admits localized wave solutions, just like any other integrable equation. We apply the Hirota bilinearization method to obtain the soliton solution of FLE. The proposed bilinearization makes use of an auxiliary function. We apply the method to FLE with a vanishing boundary condition, that is, to obtain bright soliton. We have obtained bright 1-soliton, 2-soliton solutions and propose the scheme for obtaining N-soliton solution. We have used an additional parameter which is responsible for the shift in the position of the soliton. Further analysis of the 2-soliton solution is done by asymptotic analysis. We discover that the suggested bilinearization approach, which makes use of the auxiliary function, greatly simplifies the process while still producing the desired outcome. We think that the current analysis will be helpful in understanding how FLE is used in nonlinear optics and other areas of physics.Keywords: asymptotic analysis, fokas-lenells equation, hirota bilinearization method, soliton
Procedia PDF Downloads 105612 The Spectroscopic, Molecular Structure and Electrostatic Potential, Polarizability, Hyperpolarizability, and HOMO–LUMO Analysis of Monomeric and Dimeric Structures of N-(2-Methylphenyl)-2-Nitrobenzenesulfonamide
Authors: A. Didaoui, N. Benhalima, M. Elkeurti, A. Chouaih, F. Hamzaoui
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The monomer and dimer structures of the title molecule have been obtained from density functional theory (DFT) B3LYP method with 6-31G(d,p) as basis set calculations. The optimized geometrical parameters obtained by B3LYP/6-31G(d,p) method show good agreement with experimental X-ray data. The polarizability and first order hyperpolarizability of the title molecule were calculated and interpreted. The intermolecular N–H•••O hydrogen bonds are discussed in dimer structure of the molecule. The vibrational wave numbers and their assignments were examined theoretically using the Gaussian 03 set of quantum chemistry codes. The predicted frontier molecular orbital energies at B3LYP/6-31G(d,p) method set show that charge transfer occurs within the molecule. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO–LUMO gap with the total static hyperpolarizability. The results also show that N-(2-Methylphenyl)-2-nitrobenzenesulfonamide molecule may have nonlinear optical (NLO) comportment with non-zero values.Keywords: DFT, Gaussian 03, NLO, N-(2-Methylphenyl)-2-nitrobenzenesulfonamide, polarizability
Procedia PDF Downloads 315611 Optimal Configuration for Polarimetric Surface Plasmon Resonance Sensors
Authors: Ibrahim Watad, Ibrahim Abdulhalim
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Conventional spectroscopic surface plasmon resonance (SPR) sensors are widely used, both in fundamental research and environmental monitoring as well as healthcare diagnostics. However, they still lack the low limit of detection (LOD) and there still a place for improvement. SPR conventional sensors are based on the detection of a dip in the reflectivity spectrum which is relatively wide. To improve the performance of these sensors, many techniques and methods proposed either to reduce the width of the dip or to increase the sensitivity. Together with that, profiting from the sharp jump in the phase spectrum under SPR, several works suggested the extraction of the phase of the reflected wave. However, existing phase measurement setups are in general more complicated compared to the conventional setups, require more stability and are very sensitive to external vibrations and noises. In this study, a simple polarimetric technique for phase extraction under SPR is presented, followed by a theoretical error analysis and an experimental verification. The advantages of the proposed technique upon existing techniques will be elaborated, together with conclusions regarding the best polarimetric function, and its corresponding optimal metal layer range of thicknesses to use under the conventional Kretschmann-Raether configuration.Keywords: plasmonics, polarimetry, thin films, optical sensors
Procedia PDF Downloads 392610 Ethnic Militias and Insecurity in Democratic Nigeria
Authors: Adeyemi Kamil Hamzah, Abayomi Nathaniel Oyesikun
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Throughout modern history internal strife has burdened Africa most populous nation, Nigeria. The country encompassed more than four hundred ethnic and sub ethnic groups with the different background and identities. This group has not fussed themselves together to emerge as a nation what we have are mere ethnic and religious groups i.e. Hausa/Fulani Igbo Yoruba Ijaw, Ibibio, christian, and Muslim. The source of problematic Nigeria is linked to colonial policy of segmentation, discontent to religion, faith, and ethnicity. The wave of spiral killing among the major ethnic entities with different religious affiliation has brought the process of good governance in the country to its kneel. This paper will place insecurity in Nigeria in context by reviewing the root and rise of ethnic militia. In doing so it will evaluate how the West Africa power house arrive at the point where it is today with all unprecedented unrest from regions that formed Nigeria. Both primary and secondary sources were applied for the quality of this paper. The effects of ethnic militia in realizing and actualizing political stability are equally discussed, recommendations proffered and conclusion given.Keywords: ethnic, militia, violence, insecurity, democracy
Procedia PDF Downloads 322609 Sensor Registration in Multi-Static Sonar Fusion Detection
Authors: Longxiang Guo, Haoyan Hao, Xueli Sheng, Hanjun Yu, Jingwei Yin
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In order to prevent target splitting and ensure the accuracy of fusion, system error registration is an important step in multi-static sonar fusion detection system. To eliminate the inherent system errors including distance error and angle error of each sonar in detection, this paper uses offline estimation method for error registration. Suppose several sonars from different platforms work together to detect a target. The target position detected by each sonar is based on each sonar’s own reference coordinate system. Based on the two-dimensional stereo projection method, this paper uses real-time quality control (RTQC) method and least squares (LS) method to estimate sensor biases. The RTQC method takes the average value of each sonar’s data as the observation value and the LS method makes the least square processing of each sonar’s data to get the observation value. In the underwater acoustic environment, matlab simulation is carried out and the simulation results show that both algorithms can estimate the distance and angle error of sonar system. The performance of the two algorithms is also compared through the root mean square error and the influence of measurement noise on registration accuracy is explored by simulation. The system error convergence of RTQC method is rapid, but the distribution of targets has a serious impact on its performance. LS method can not be affected by target distribution, but the increase of random noise will slow down the convergence rate. LS method is an improvement of RTQC method, which is widely used in two-dimensional registration. The improved method can be used for underwater multi-target detection registration.Keywords: data fusion, multi-static sonar detection, offline estimation, sensor registration problem
Procedia PDF Downloads 158608 Teaching Science Content Area Literacy to 21st Century Learners
Authors: Melissa C. Ingram
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The use of new literacies within science classrooms needs to be balanced by teachers to both teach different forms of communication while assessing content area proficiency. Using new literacies such as Twitter and Facebook needs to be incorporated into science content area literacy studies in addition to continuing to use generally-accepted forms of scientific content area presentation, which include scientific papers and textbooks. The research question this literature review seeks to answer is “What are some ways in which new forms of literacy are better suited to teach scientific content area literacy to 21st Century learners?” The research question is addressed through a literature review that highlights methods currently being used to educate the next wave of learners in the world of science content area literacy. Both temporal discourse analysis (TDA) and critical discourse analysis (CDA) were used to determine the need to use new literacies to teach science content area literacy. Increased use of digital technologies and a change in science content area pedagogy were explored.Keywords: science content area literacy, new literacies, critical discourse analysis, temporal discourse analysis
Procedia PDF Downloads 214607 Dimensionality and Superconducting Parameters of YBa2Cu3O7 Foams
Authors: Michael Koblischka, Anjela Koblischka-Veneva, XianLin Zeng, Essia Hannachi, Yassine Slimani
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Superconducting foams of YBa2Cu3O7 (abbreviated Y-123) were produced using the infiltration growth (IG) technique from Y2BaCuO5 (Y-211) foams. The samples were investigated by SEM (scanning electron microscopy) and electrical resistivity measurements. SEM observations indicated the specific microstructure of the foam struts with numerous tiny Y-211 particles (50-100 nm diameter) embedded in channel-like structures between the Y-123 grains. The investigation of the excess conductivity of different prepared composites was analyzed using Aslamazov-Larkin (AL) model. The investigated samples comprised of five distinct fluctuation regimes, namely short-wave (SWF), one-dimensional (1D), two-dimensional (2D), three-dimensional (3D), and critical (CR) fluctuations regimes. The coherence length along the c-axis at zero-temperature (ξc(0)), lower and upper critical magnetic fields (Bc1 and Bc2), critical current density (Jc) and numerous other superconducting parameters were estimated from the data. The analysis reveals that the presence of the tiny Y-211 particles alters the excess conductivity and the fluctuation behavior observed in standard YBCO samples.Keywords: Excess conductivity, Foam, Microstructure, Superconductor YBa2Cu3Oy
Procedia PDF Downloads 158606 Changing Human Resources Policies in Companies after the COVID-19 Pandemic
Authors: Murat Çolak, Elifnaz Tanyıldızı
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Today, human mobility with globalization has increased the interaction between countries significantly; although this contact has advanced societies in terms of civilization, it has also increased the likelihood of pandemics. The coronavirus (COVID-19) pandemic, which caused the most loss of life among them, turned into a global epidemic by covering the whole world in a short time. While there was an explosion in demand in some businesses around the world, some businesses temporarily stopped or had to stop their activities. The businesses affected by the crisis had to adapt to the new legal regulations but had to make changes in matters such as their working styles, human resources practices, and policies. One of the measures taken into account is the reduction of the workforce. The current COVID-19 crisis has posed serious challenges for many organizations and has generated an unprecedented wave of termination notices. This study examined examples of companies affected by the pandemic process and changed their working policies after the pandemic. This study aims to reveal the impact of the global COVID-19 pandemic on human resources policies and employees and how these situations will affect businesses in the future.Keywords: human resource management, crisis management, COVID-19, business function
Procedia PDF Downloads 87605 Reducing Uncertainty of Monte Carlo Estimated Fatigue Damage in Offshore Wind Turbines Using FORM
Authors: Jan-Tore H. Horn, Jørgen Juncher Jensen
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Uncertainties related to fatigue damage estimation of non-linear systems are highly dependent on the tail behaviour and extreme values of the stress range distribution. By using a combination of the First Order Reliability Method (FORM) and Monte Carlo simulations (MCS), the accuracy of the fatigue estimations may be improved for the same computational efforts. The method is applied to a bottom-fixed, monopile-supported large offshore wind turbine, which is a non-linear and dynamically sensitive system. Different curve fitting techniques to the fatigue damage distribution have been used depending on the sea-state dependent response characteristics, and the effect of a bi-linear S-N curve is discussed. Finally, analyses are performed on several environmental conditions to investigate the long-term applicability of this multistep method. Wave loads are calculated using state-of-the-art theory, while wind loads are applied with a simplified model based on rotor thrust coefficients.Keywords: fatigue damage, FORM, monopile, Monte Carlo, simulation, wind turbine
Procedia PDF Downloads 249604 Verification and Application of Finite Element Model Developed for Flood Routing in Rivers
Authors: A. L. Qureshi, A. A. Mahessar, A. Baloch
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Flood wave propagation in river channel flow can be enunciated by nonlinear equations of motion for unsteady flow. However, it is difficult to find analytical solution of these complex non-linear equations. Hence, verification of the numerical model should be carried out against field data and numerical predictions. This paper presents the verification of developed finite element model applying for unsteady flow in the open channels. The results of a proposed model indicate a good matching with both Preissmann scheme and HEC-RAS model for a river reach of 29 km at both sites (15 km from upstream and at downstream end) for discharge hydrographs. It also has an agreeable comparison with the Preissemann scheme for the flow depth (stage) hydrographs. The proposed model has also been applying to forecast daily discharges at 400 km downstream from Sukkur barrage, which demonstrates accurate model predictions with observed daily discharges. Hence, this model may be utilized for predicting and issuing flood warnings about flood hazardous in advance.Keywords: finite element method, Preissmann scheme, HEC-RAS, flood forecasting, Indus river
Procedia PDF Downloads 493603 Numerical Investigation on Tsunami Suppression by Submerged Breakwater
Authors: Tasuku Hongo, Hiroya Mamori, Naoya Fukushima, Makoto Yamamoto
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A tsunami induced by an earthquake gives a severe disaster in coastal area. As well known, the huge earthquake in Japan 2011 induced a huge tsunami and the tsunami caused serious damage in the Tohoku and Kanto area. Although breakwaters were constructed in the coast to suppress the tsunami, these were collapsed, and it resulted in severe disasters. In order to decrease the tsunami disaster, we propose the submerged breakwaters and investigate its effect on the tsunami behavior by means of numerical simulations. In order to reproduce tsunami and capture its interface, we employed a moving particle method which is one of the Lagragian methods. Different from ordinary breakwaters, the present breakwater is located in the under-sea. An effective installation condition is investigated by the parametric study. The results show that the submerged breakwater can decrease the wave force by the tsunami. Moreover, the combination of two submerged breakwaters can reduce the tsunami safely and effectively. Therefore, the present results give the effective condition of the installation of the under-sea breakwaters and its mechanism.Keywords: coastal area, tsunami force reduction, MPS method, submerged breakwater
Procedia PDF Downloads 158602 Finite Element Simulation for Preliminary Study on Microorganism Detection System
Authors: Muhammad Rosli Abdullah, Noor Hasmiza Harun
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A microorganism detection system has a potential to be used with the advancement in a biosensor development. The detection system requires an optical sensing system, microfluidic device and biological reagent. Although, the biosensors are available in the market, a label free and a lab-on-chip approach will promote a flexible solution. As a preliminary study of microorganism detection, three mechanisms such as Total Internal Reflection (TIR), Micro Fluidic Channel (MFC) and magnetic-electric field propagation were study and simulated. The objective are to identify the TIR angle, MFC parabolic flow and the wavelength for the microorganism detection. The simulation result indicates that evanescent wave is achieved when TIR angle > 42°, the corner and centre of a parabolic velocity are 0.02 m/s and 0.06 m/s respectively, and a higher energy distribution of a perfect electromagnetic scattering with dipole resonance radiation occurs at 500 nm. This simulation is beneficial to determine the components of the microorganism detection system that does not rely on classical microbiological, immunological and genetic methods which are laborious, time-consuming procedures and confined to specialized laboratories with expensive instrumentation equipment.Keywords: microorganism, microfluidic, total internal reflection, lab on chip
Procedia PDF Downloads 264601 Decision Support System for the Management of the Shandong Peninsula, China
Authors: Natacha Fery, Guilherme L. Dalledonne, Xiangyang Zheng, Cheng Tang, Roberto Mayerle
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A Decision Support System (DSS) for supporting decision makers in the management of the Shandong Peninsula has been developed. Emphasis has been given to coastal protection, coastal cage aquaculture and harbors. The investigations were done in the framework of a joint research project funded by the German Ministry of Education and Research (BMBF) and the Chinese Academy of Sciences (CAS). In this paper, a description of the DSS, the development of its components, and results of its application are presented. The system integrates in-situ measurements, process-based models, and a database management system. Numerical models for the simulation of flow, waves, sediment transport and morphodynamics covering the entire Bohai Sea are set up based on the Delft3D modelling suite (Deltares). Calibration and validation of the models were realized based on the measurements of moored Acoustic Doppler Current Profilers (ADCP) and High Frequency (HF) radars. In order to enable cost-effective and scalable applications, a database management system was developed. It enhances information processing, data evaluation, and supports the generation of data products. Results of the application of the DSS to the management of coastal protection, coastal cage aquaculture and harbors are presented here. Model simulations covering the most severe storms observed during the last decades were carried out leading to an improved understanding of hydrodynamics and morphodynamics. Results helped in the identification of coastal stretches subjected to higher levels of energy and improved support for coastal protection measures.Keywords: coastal protection, decision support system, in-situ measurements, numerical modelling
Procedia PDF Downloads 187600 First Principle Calculations of the Structural and Optoelectronic Properties of Cubic Perovskite CsSrF3
Authors: Meriem Harmel, Houari Khachai
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We have investigated the structural, electronic and optical properties of a compound perovskite CsSrF3 using the full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, both the local density approximation (LDA) and the generalized gradient approximation (GGA) were used for exchange-correlation potential calculation. The ground state properties such as lattice parameter, bulk modulus and its pressure derivative were calculated and the results are compared whit experimental and theoretical data. Electronic and bonding properties are discussed from the calculations of band structure, density of states and electron charge density, where the fundamental energy gap is direct under ambient conditions. The contribution of the different bands was analyzed from the total and partial density of states curves. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 35.0 eV. This is the first quantitative theoretical prediction of the optical properties for the investigated compound and still awaits experimental confirmations.Keywords: DFT, fluoroperovskite, electronic structure, optical properties
Procedia PDF Downloads 455599 Study, Design, Simulation and Fabrication of Microwave Slot Antenna
Authors: Khaled A. Madi, Rema A. Mousbahi, Mostafa B. Abuitbel, Abdualhakim O. Nagi
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Antenna perhaps is the most important part of any communication system, it determines the overall efficiency and the direction of radiation of the system. Antennas vary in shape and size on a very wide range. For fast moving vehicles, the antenna should offer as litter aerodynamic resistance as possible. Slot antenna is best suited for this purpose. It offers very little aerodynamic resistance, compact, easy to feed and fabricate. This work presented in this paper deals with the investigation of a half wave slot antenna. The antenna has been studied, analyzed, designed, simulated, fabrication, and tested at the X-band. The field of antenna study is an extremely vast one, and to grasp the fundamentals, two pronged approaches have been used, and the focus was on the fabrication and testing of a slot waveguide directional antenna. Focuses on the design and simulation of slot antennas with an emphasis on optimization of a 9.1 GHz a rectangular waveguide have been used to feed slot antenna. A microwave fed slot antenna used in the communication lab was also simulated. The results have been presented and compared with the expected values, where a good agreement was achieved between the simulation and experimental results.Keywords: microwave, slot antenna, simulation, fabrication
Procedia PDF Downloads 122598 Software Quality Assurance in 5G Technology-Redefining Wireless Communication: A Comprehensive Survey
Authors: Sumbal Riaz, Sardar-un-Nisa, Mehreen Sirshar
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5G - The 5th generation of mobile phone and data communication standards is the next edge of innovation for whole mobile industry. 5G is Real Wireless World System and it will provide a totally wireless communication system all over the world without limitations. 5G uses many 4g technologies and it will hit the market in 2020. This research is the comprehensive survey on the quality parameters of 5G technology.5G provide High performance, Interoperability, easy roaming, fully converged services, friendly interface and scalability at low cost. To meet the traffic demands in future fifth generation wireless communications systems will include i) higher densification of heterogeneous networks with massive deployment of small base stations supporting various Radio Access Technologies (RATs), ii) use of massive Multiple Input Multiple Output (MIMO) arrays, iii) use of millimetre Wave spectrum where larger wider frequency bands are available, iv) direct device to device (D2D) communication, v) simultaneous transmission and reception, vi) cognitive radio technology.Keywords: 5G, 5th generation, innovation, standard, wireless communication
Procedia PDF Downloads 437597 Imaging 255nm Tungsten Thin Film Adhesion with Picosecond Ultrasonics
Authors: A. Abbas, X. Tridon, J. Michelon
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In the electronic or in the photovoltaic industries, components are made from wafers which are stacks of thin film layers of a few nanometers to serval micrometers thickness. Early evaluation of the bounding quality between different layers of a wafer is one of the challenges of these industries to avoid dysfunction of their final products. Traditional pump-probe experiments, which have been developed in the 70’s, give a partial solution to this problematic but with a non-negligible drawback. In fact, on one hand, these setups can generate and detect ultra-high ultrasounds frequencies which can be used to evaluate the adhesion quality of wafer layers. But, on the other hand, because of the quiet long acquisition time they need to perform one measurement, these setups remain shut in punctual measurement to evaluate global sample quality. This last point can lead to bad interpretation of the sample quality parameters, especially in the case of inhomogeneous samples. Asynchronous Optical Sampling (ASOPS) systems can perform sample characterization with picosecond acoustics up to 106 times faster than traditional pump-probe setups. This last point allows picosecond ultrasonic to unlock the acoustic imaging field at the nanometric scale to detect inhomogeneities regarding sample mechanical properties. This fact will be illustrated by presenting an image of the measured acoustical reflection coefficients obtained by mapping, with an ASOPS setup, a 255nm thin-film tungsten layer deposited on a silicone substrate. Interpretation of the coefficient reflection in terms of bounding quality adhesion will also be exposed. Origin of zones which exhibit good and bad quality bounding will be discussed.Keywords: adhesion, picosecond ultrasonics, pump-probe, thin film
Procedia PDF Downloads 151596 Rumination Time and Reticuloruminal Temperature around Calving in Eutocic and Dystocic Dairy Cows
Authors: Levente Kovács, Fruzsina Luca Kézér, Ottó Szenci
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Prediction of the onset of calving and recognizing difficulties at calving has great importance in decreasing neonatal losses and reducing the risk of health problems in the early postpartum period. In this study, changes of rumination time, reticuloruminal pH and temperature were investigated in eutocic (EUT, n = 10) and dystocic (DYS, n = 8) dairy cows around parturition. Rumination time was continuously recorded using an acoustic biotelemetry system, whereas reticuloruminal pH and temperature were recorded using an indwelling and wireless data transmitting system. The recording period lasted from 3 d before calving until 7 days in milk. For the comparison of rumination time and reticuloruminal characteristics between groups, time to return to baseline (the time interval required to return to baseline from the delivery of the calf) and area under the curve (AUC, both for prepartum and postpartum periods) were calculated for each parameter. Rumination time decreased from baseline 28 h before calving both for EUT and DYS cows (P = 0.023 and P = 0.017, respectively). After 20 h before calving, it decreased onwards to reach 32.4 ± 2.3 and 13.2 ± 2.0 min/4 h between 8 and 4 h before delivery in EUT and DYS cows, respectively, and then it decreased below 10 and 5 min during the last 4 h before calving (P = 0.003 and P = 0.008, respectively). Until 12 h after delivery rumination time reached 42.6 ± 2.7 and 51.0 ± 3.1 min/4 h in DYS and EUT dams, respectively, however, AUC and time to return to baseline suggested lower rumination activity in DYS cows than in EUT dams for the 168-h postpartum observational period (P = 0.012 and P = 0.002, respectively). Reticuloruminal pH decreased from baseline 56 h before calving both for EUT and DYS cows (P = 0.012 and P = 0.016, respectively), but did not differ between groups before delivery. In DYS cows, reticuloruminal temperature decreased from baseline 32 h before calving by 0.23 ± 0.02 °C (P = 0.012), whereas in EUT cows such a decrease was found only 20 h before delivery (0.48 ± 0.05 °C, P < 0.01). AUC of reticuloruminal temperature calculated for the prepartum period was greater in EUT cows than in DYS cows (P = 0.042). During the first 4 h after calving, it decreased from 39.7 ± 0.1 to 39.00 ± 0.1 °C and from 39.8 ± 0.1 to 38.8 ± 0.1 °C in EUT and DYS cows, respectively (P < 0.01 for both groups) and reached baseline levels after 35.4 ± 3.4 and 37.8 ± 4.2 h after calving in EUT and DYS cows, respectively. Based on our results, continuous monitoring of changes in rumination time and reticuloruminal temperature seems to be promising in the early detection of cows with a higher risk of dystocia. Depressed postpartum rumination time of DYS cows highlights the importance of the monitoring of cows experiencing difficulties at calving.Keywords: reticuloruminal pH, reticuloruminal temperature, rumination time, dairy cows, dystocia
Procedia PDF Downloads 308595 A New PWM Command for Cascaded H-Bridge Multilevel Increasing the Quality and Reducing Harmonics
Authors: Youssef Babkrani, S. Hiyani, A. Naddami, K. Choukri, M. Hilal
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Power Quality has been a problem ever since electrical power was invented and in recent years, it has become the main interest of researchers who are still concerned about finding ways to reduce its negative influence on electrical devices. In this paper we aim to improve the power quality output for H- bridge multilevel inverter used with solar Photovoltaic (PV) panels, we propose a new switching technique that uses a pulse width modulation method (PWM) aiming to reduce the harmonics. This new method introduces a sinusoidal wave compared with modified trapezoidal carriers used to generate the pulses. This new trapezoid carrier waveform is being implemented with different sinusoidal PWM dispositions such as phase disposition (PWM PD), phase opposition disposition (PWM POD), and (PWM APOD) alternative phase opposition disposition and compared with the conventional ones. Using Matlab Simulink R2014a the line voltage and total harmonic distortions (THD) simulated and the quality are increased in spite of variations of DC introduced.Keywords: carrier waveform, phase disposition (PD), phase opposition disposition (POD), alternative phase opposition disposition (APOD), total harmonics distortion (THD)
Procedia PDF Downloads 278594 Runoff Simulation by Using WetSpa Model in Garmabrood Watershed of Mazandaran Province, Iran
Authors: Mohammad Reza Dahmardeh Ghaleno, Mohammad Nohtani, Saeedeh Khaledi
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Hydrological models are applied to simulation and prediction floods in watersheds. WetSpa is a distributed, continuous and physically model with daily or hourly time step that explains of precipitation, runoff and evapotranspiration processes for both simple and complex contexts. This model uses a modified rational method for runoff calculation. In this model, runoff is routed along the flow path using Diffusion-Wave Equation which depend on the slope, velocity and flow route characteristics. Garmabrood watershed located in Mazandaran province in Iran and passing over coordinates 53° 10´ 55" to 53° 38´ 20" E and 36° 06´ 45" to 36° 25´ 30"N. The area of the catchment is about 1133 km2 and elevations in the catchment range from 213 to 3136 m at the outlet, with average slope of 25.77 %. Results of the simulations show a good agreement between calculated and measured hydrographs at the outlet of the basin. Drawing upon Nash-Sutcliffe Model Efficiency Coefficient for calibration periodic model estimated daily hydrographs and maximum flow rate with an accuracy up to 61% and 83.17 % respectively.Keywords: watershed simulation, WetSpa, runoff, flood prediction
Procedia PDF Downloads 329593 Digital Holographic Interferometric Microscopy for the Testing of Micro-Optics
Authors: Varun Kumar, Chandra Shakher
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Micro-optical components such as microlenses and microlens array have numerous engineering and industrial applications for collimation of laser diodes, imaging devices for sensor system (CCD/CMOS, document copier machines etc.), for making beam homogeneous for high power lasers, a critical component in Shack-Hartmann sensor, fiber optic coupling and optical switching in communication technology. Also micro-optical components have become an alternative for applications where miniaturization, reduction of alignment and packaging cost are necessary. The compliance with high-quality standards in the manufacturing of micro-optical components is a precondition to be compatible on worldwide markets. Therefore, high demands are put on quality assurance. For quality assurance of these lenses, an economical measurement technique is needed. For cost and time reason, technique should be fast, simple (for production reason), and robust with high resolution. The technique should provide non contact, non-invasive and full field information about the shape of micro- optical component under test. The interferometric techniques are noncontact type and non invasive and provide full field information about the shape of the optical components. The conventional interferometric technique such as holographic interferometry or Mach-Zehnder interferometry is available for characterization of micro-lenses. However, these techniques need more experimental efforts and are also time consuming. Digital holography (DH) overcomes the above described problems. Digital holographic microscopy (DHM) allows one to extract both the amplitude and phase information of a wavefront transmitted through the transparent object (microlens or microlens array) from a single recorded digital hologram by using numerical methods. Also one can reconstruct the complex object wavefront at different depths due to numerical reconstruction. Digital holography provides axial resolution in nanometer range while lateral resolution is limited by diffraction and the size of the sensor. In this paper, Mach-Zehnder based digital holographic interferometric microscope (DHIM) system is used for the testing of transparent microlenses. The advantage of using the DHIM is that the distortions due to aberrations in the optical system are avoided by the interferometric comparison of reconstructed phase with and without the object (microlens array). In the experiment, first a digital hologram is recorded in the absence of sample (microlens array) as a reference hologram. Second hologram is recorded in the presence of microlens array. The presence of transparent microlens array will induce a phase change in the transmitted laser light. Complex amplitude of object wavefront in presence and absence of microlens array is reconstructed by using Fresnel reconstruction method. From the reconstructed complex amplitude, one can evaluate the phase of object wave in presence and absence of microlens array. Phase difference between the two states of object wave will provide the information about the optical path length change due to the shape of the microlens. By the knowledge of the value of the refractive index of microlens array material and air, the surface profile of microlens array is evaluated. The Sag of microlens and radius of curvature of microlens are evaluated and reported. The sag of microlens agrees well within the experimental limit as provided in the specification by the manufacturer.Keywords: micro-optics, microlens array, phase map, digital holographic interferometric microscopy
Procedia PDF Downloads 492592 Effect of Wind and Humidity on Microwave Links in North West Libya
Authors: M. S. Agha, A. M. Eshahiry, S. A. Aldabbar, Z. M. Alshahri
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The propagation of microwave is affected by rain and dust particles causing signal attenuation and de-polarization. Computations of these effects require knowledge of the propagation characteristics of microwave and millimeter wave energy in the climate conditions of the studied region. This paper presents effect of wind and humidity on wireless communication such as microwave links in the North West region of Libya (Al-Khoms). The experimental procedure is done on three selected antennae towers (Nagaza station, Al-Khoms center station, Al-Khoms gateway station) for determining the attenuation loss per unit length and cross-polarization discrimination (XPD) change. Dust particles are collected along the region of the study, to measure the particle size distribution (PSD), calculate the concentration, and chemically analyze the contents, then the dielectric constant can be calculated. The results show that humidity and dust, antenna height and the visibility affect both attenuation and phase shift; in which, a few considerations must be taken into account in the communication power budget.Keywords: : Attenuation, scattering, transmission loss.
Procedia PDF Downloads 208591 Effects of Two Cross Focused Intense Laser Beams On THz Generation in Rippled Plasma
Authors: Sandeep Kumar, Naveen Gupta
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Terahertz (THz) generation has been investigated by beating two cosh-Gaussian laser beams of the same amplitude but different wavenumbers and frequencies through rippled collisionless plasma. The ponderomotive force is operative which is induced due to the intensity gradient of the laser beam over the cross-section area of the wavefront. The electrons evacuate towards a low-intensity regime, which modifies the dielectric function of the medium and results in cross focusing of cosh-Gaussian laser beams. The evolution of spot size of laser beams has been studied by solving nonlinear Schrodinger wave equation (NLSE) with variational technique. The laser beams impart oscillations to electrons which are enhanced with ripple density. The nonlinear oscillatory motion of electrons gives rise to a nonlinear current density driving THz radiation. It has been observed that the periodicity of the ripple density helps to enhance the THz radiation.Keywords: rippled collisionless plasma, cosh-gaussian laser beam, ponderomotive force, variational technique, nonlinear current density
Procedia PDF Downloads 193590 Interesting Behavior of Non-Thermal Plasma Photonic Crystals
Authors: A. Mousavi, S. Sadegzadeh
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In this research, the effect of non-thermal micro plasma with non-Maxwellian distribution function on the one dimensional plasma photonic crystals containing alternate plasma-dielectric layers, has been studied. By using Kronig Penny model, the dispersion relation of electromagnetic modes for such a periodic structure is obtained. In this study we take two plasma photonic crystals with different dielectric layers: the first one with Silicon monoxide named PPCI, and the second one with Tellurium dioxide named PPCII. The effects of the plasma layer thickness and the material of the dielectric layer on the plasma photonic crystal band gaps have been illustrated in the dispersion relation and the group velocity figures. Results revealed that in such a system, the non-thermal plasma exerts stronger limit on the wave’s propagation. In another word, for the non-thermal plasma photonic crystals (NPPC), there are two distinct regions in the dispersion plot. The upper region consists of alternate band gaps in such a way that both width and length of the bands decrease gradually as the band gaps order increases. Whereas in the lower region where v_ph > 20 c (for PPCI), waves will not be allowed to propagate.Keywords: band gap, dispersion relation, non-thermal plasma, plasma photonic crystal
Procedia PDF Downloads 530589 A Longitudinal Study of Academic Achievement: Parental Warm Support and Moderating Role of Teacher’s Emotional Support and Mediating Role of Self Control on Academic Achievement
Authors: Maaza Saeed, Caina Li
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The current 2-wave longitudinal study attempts to illuminate the well-established association between parental warm support and academic achievement through the mediating role of self-control while taking into account the moderating role of teacher emotional support. The present research has assessed 2569 Chinese students (aged 10-18 years, M = 13.27, SD = 0.67). They were recruited from the three public middle schools in Xi’an, a middle-sized city in the central part of China. Meditation analysis revealed that self-control mediated the relationship between parental warm support and academic achievement. Additionally, it was found the direct effect of parental warm support was not significant after controlling for the age and gender. Furthermore, moderation analysis revealed high parental warm support and higher teacher emotional support was related to increased self-control compared to lower teacher emotion support. The findings highlighted the importance of parental warm support, teacher emotional support, and self-control on academic achievement.Keywords: self control, academic achievement, teacher emotional support/conflict, adolescent
Procedia PDF Downloads 267588 VANETs: Security Challenges and Future Directions
Authors: Jared Oluoch
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Connected vehicles are equipped with wireless sensors that aid in Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication. These vehicles will in the near future provide road safety, improve transport efficiency, and reduce traffic congestion. One of the challenges for connected vehicles is how to ensure that information sent across the network is secure. If security of the network is not guaranteed, several attacks can occur, thereby compromising the robustness, reliability, and efficiency of the network. This paper discusses existing security mechanisms and unique properties of connected vehicles. The methodology employed in this work is exploratory. The paper reviews existing security solutions for connected vehicles. More concretely, it discusses various cryptographic mechanisms available, and suggests areas of improvement. The study proposes a combination of symmetric key encryption and public key cryptography to improve security. The study further proposes message aggregation as a technique to overcome message redundancy. This paper offers a comprehensive overview of connected vehicles technology, its applications, its security mechanisms, open challenges, and potential areas of future research.Keywords: VANET, connected vehicles, 802.11p, WAVE, DSRC, trust, security, cryptography
Procedia PDF Downloads 303587 Argon/Oxygen Plasma Surface Modification of Biopolymers for Improvement of Wettability and Wear Resistance
Authors: Binnur Sagbas
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Artificial joint replacements such as total knee and total hip prosthesis have been applied to the patients who affected by osteoarthritis. Although different material combinations are used for these joints, biopolymers are most commonly preferred materials especially for acetabular cup and tibial component of hip and knee joints respectively. The main limitation that shortens the service life of these prostheses is wear. Wear is complicated phenomena and it must be considered with friction and lubrication. In this study, micro wave (MW) induced argon+oxygen plasma surface modification were applied on ultra-high molecular weight polyethylene (UHMWPE) and vitamin E blended UHMWPE (VE-UHMWPE) biopolymer surfaces to improve surface wettability and wear resistance of the surfaces. Contact angel measurement method was used for determination of wettability. Ball-on-disc wear test was applied under 25% bovine serum lubrication conditions. The results show that surface wettability and wear resistance of both material samples were increased by plasma surface modification.Keywords: artificial joints, plasma surface modification, UHMWPE, vitamin E, wear
Procedia PDF Downloads 301586 Reduction of Energy Consumption Using Smart Home Techniques in the Household Sector
Authors: Ahmed Al-Adaileh, Souheil Khaddaj
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Outcomes of exhaustion of natural resources started influencing each spirit on this planet. Energy is an essential factor in this aspect. To restore the circumstance to the appropriate track, all attempts must focus on two fundamental branches: producing electricity from clean and renewable reserves and decreasing the overall unnecessary consumption of energy. The focal point of this paper will be on lessening the power consumption in the household's segment. This paper is an attempt to give a clear understanding of a framework called Reduction of Energy Consumption in Household Sector (RECHS) and how it should help householders to reduce their power consumption by substituting their household appliances, turning-off the appliances when stand-by modus is detected, and scheduling their appliances operation periods. Technically, the framework depends on utilizing Z-Wave compatible plug-ins which will be connected to the usual house devices to gauge and control them remotely and semi-automatically. The suggested framework underpins numerous quality characteristics, for example, integrability, scalability, security and adaptability.Keywords: smart energy management systems, internet of things, wireless mesh networks, microservices, cloud computing, big data
Procedia PDF Downloads 181585 Half Mode Substrate Integrated Wave Guide of Band Pass Filter Based to Defected Ground Structure Cells
Authors: Damou Mehdi, Nouri Keltoum, Feham Mohammed, Khazini Mohammed, Bouazza Tayb Habibi Chawki
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The Half mode SIW filter is treated by two softwares (HFSS (High Frequency Structure Simulator) and CST (Computer Simulation Technology)). The filter HMSIW has a very simple structure and a very compact size. The simulated results by CST are presented and compared with the results simulated by a high-frequency structure simulator. Good agreement between the simulated CST and simulated results by HFSS is observed. By cascading two of them according to design requirement, a X-band bandpass filter is designed and simulated to meet compact size, low insertion loss, good return loss as well as second harmonic suppression. As an example, we designed the proposed HMSIW filter at X band by HFSS. The filter has a pass-band from 7.3 GHz to 9.8 GHz, and its relative operating fraction bandwidth is 29.5 %. There are one transmission zeros are located at 14.4 GHz.Keywords: substrate integrated waveguide, filter, HMSIW, defected ground structures (DGS), simulation BPF
Procedia PDF Downloads 579584 Microstrip Bandpass Filter with Wide Stopband and High Out-of-Band Rejection Based on Inter-Digital Capacitor
Authors: Mohamad Farhat, Bal Virdee
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This paper present a compact Microstrip Bandpass filter exhibiting a very wide stop band and high selectivity. The filter comprises of asymmetric resonator structures, which are interconnected by an inter-digital capacitor to enable the realization of a wide bandwidth with high rejection level. High selectivity is obtained by optimizing the parameters of the interdigital capacitor. The filter has high out-of-band rejection (> 30 dB), less than 0.6 dB of insertion-loss, up to 5.5 GHz spurii free, and about 18 dB of return-loss. Full-wave electromagnetic simulator ADSTM (Mom) is used to analyze and optimize the prototype bandpass filter. The proposed technique was verified practically to validate the design methodology. The experimental results of the prototype circuit are presented and a good agreement was obtained comparing with the simulation results. The dimensions of the proposed filter are 32 x 24 mm2.The filter’s characteristics and compact size make it suitable for wireless communication systems.Keywords: asymmetric resonator, bandpass filter, microstrip, spurious suppression, ultra-wide stop band
Procedia PDF Downloads 178