Abstract: The present paper investigates the utilization of the magnetic Barkhausen noise and magnetic permeability methods for the nondestructive characterization of annealed non-oriented electrical steel samples which were isothermally annealed in a wide range of temperatures (400°C – 950°C) and subsequently cooled in air. The resulting magnetic properties were compared with the microstructural changes occurring during annealing.
Abstract: Desalination can be carried out in water to remove any salt. The process takes place after tertiary treatment of municipal and industrial waste water as a final treatment before discharge to the recipient. The desalination of seawater using Reverse Osmosis (R.O.) technique is now a tried and proven technology that can provide high-quality water supply. The resulting from R.O. water is not suitable for drinking. The method proposed in this paper is selected desalination via zeolitic micro-particles. The method exhibits some significant advantages such as the easy recovery and reuse of powders (with negligible losses during the release process of trapped ions in liquid solution), the selective removal of ions and the ability of producing directly potable water without the need for further enrichment.
Abstract: We present computational analysis of optical nanostructures, including but not limited to frequency-selective surfaces, metamaterials, nanoantennas, nanowires, and photonic crystals. A rigorous implementation based on surface integral equations and the multilevel fast multipole algorithm is developed for the analysis of such three-dimensional complex structures, without resorting to infinity, self-similarity, periodicity or homogeneity assumptions. The developed simulation environment provides accurate analysis of nanooptical structures to expand our knowledge on these important components of the state-of-the-art technology.
Abstract: Conductive polymer-electrospun polymer nanofiber network was combined to host iron oxide nanoparticles providing micrometer thick sensing interface. The sensor has fabricated as free-standing fabric exhibiting 10 to 100 KOhm base resistivity upon bias applied. The moving object has been sensed through the electrostatic interactions between fibers and object. The sensing range has been found to be 1-5 cm above the surface of fabric. By the controlled combination of conductive polymers electrospun polymer nanofibers effective device miniaturization has been provided without loss of performance. The noncontact motion sensor platform has unique flexibility and light weight holding a potential for wearable sensor technology.
Abstract: The rapid developments in nanoscience, and its applications on biomedical areas have a large impact on drug delivery, tissue engineering, sensing, and diagnosis. Gold is widely investigated nanomaterial for the last couple of decades, since it has unique surface properties and very low toxicity to biological environment. In this work, we present a novel synthesis of gold nanoparticles (GNPs) exhibiting both visible and near-IR absorbance without agglomeration. The surface of GNPs were analyzed by routine methods and the binding kinetics were investigated by Surface Plasmon Resonance (SPR) Spectroscopy. The unique optical properties of near-IR asorbing GNP colloids hold promise for biological applications.
Abstract: For Visible Light Communication (VLC) systems, photo receiver is very important for obtaining low noisy modulated signal at receiver side since the pure modulated signal is easy demodulated. Therefore, we give a comparison of performance of three type photo receivers in this paper. In first application, we use a photoresistor to detect the modulated signal. It is referred as CDS (cadmium-sulfide) resistor. Another detector is solar cell unit. The other receiver is selected photodiode detector. It is shown from experimental results that the most appropriate modulated signal is obtained at output of photodiode. The output of solar cell consists of very complex signal compared with output of photoresistor. Additionally, we use PPM (Pulse Position Modulation) technique for transmission of data signal.
Abstract: The effect of Hydrogen on thermo-mechanical properties and performance of metals and alloys are of critical importance. In recent years, the relevance of H-metal interactions has been broadened into functional metallic compounds and alloys as they find use in energy and medical applications. Here, we aim to assess the influence of H-content on thermal, physical, chemical, and mechanical properties on Nickel-Aluminum alloys using Molecular Dynamics (MD) and Density Functional Theory (DFT) methods. We report studies on Ni3Al, Al3Ni, AlNi with H-content ranging from 1% to 10% at elevated temperatures for different structures such as B1, B2, L10, A4 and random and ordered in L12 to establish enthalpy-temperature-concentration, volume-temperature concentration, volume-pressure-concentration relationships. From these relationships we derive thermodynamic and mechanical properties such as thermal expansion, bulk modulus and Young modulus.
Abstract: In this thesis, the RF front-end was done at K/Ka (18-27 GHz/26.5-40 GHz) bands used for satellite communication and satellite TV . In this study, vertical polarized signal transmission and horizontal polarized signal reception were performed. The design is set to be compatible with TURKSAT 4B . RF front-end is consist of an offset dish providing high gain and low side lobe level (SLL) for collecting the signal, a circular horn antenna which is compatible with RHCP (Right Hand Circular Polarization) and LHCP (Left Hand Circular Polarization) polarizations at the focal point of the dish, to separate dual polarization an orthomode transducer (OMT) and a transmit reject filter to prevent the receiver from the strong signal generated at the transmitter side (cross-pol). In the design waveguide structures is used to work in microwave frequencies and for high power delivery requirements. AWR Microwave Office, Computer Simulation Technology (CST) and MATLAB (Matrix Laboratory) programs are used for simulation, optimization and calculations.
Abstract: In this work, the preparation of cadmium telluride (CdTe) nanoparticles by aqueous solution method is presented. The preparation process was performed in the presence of an acidic agent (L-cys) at certain pH value. The x-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) of the prepared samples showed that poly crystalline structure with lowest particle size can be produced by controlling the period of heating process after the preparation step. Accordingly, this parameter can be used carefully to control the surface roughness of nanoscale CdTe samples to serve certain applications requiring some determined values of particle size and surface roughness.
Abstract: Wet adhesion is achieved by mussels so naturally. Their adhesion mechanism has inspired scientists to obtain wet adhesives for a long time. The amino acid 3,4-dihydroxyphenylalanine (DOPA) produced by mussels adheres to different types of surfaces and also contributes to cohesive interactions. Here, we showed the spontaneous adhesion of DOPA functionalized four armed poly (ethylene glycol) (PEG) polymer to spin labeled polystyrene (SL-PS) nanosurfaces by electron paramagnetic resonance (EPR) spectroscopy. In addition to DOPA, adhesion property of another amino acid of tryptophan (Trp) was studied. Trp attached four armed PEG polymers did not adhere to the surface of SL-PS in the force free condition. However, two armed DOPA and two armed Trp functionalized PEG adhere to the PS.