Recent advances in wireless communication systems have made use of OFDM technique to achieve high data rate transmission. The sensitivity to frequency offset between the carrier frequencies of the transmitter and the receiver is one of the major problems in OFDM systems. This frequency offset introduces inter-carrier interference in the OFDM symbol and then the BER performance reduced. In this paper a Multi-Orthogonal-Band MOB-OFDM system based on the Discrete Hartley Transform (DHT) is proposed to improve the BER performance. The OFDM spectrum is divided into equal sub-bands and the data is divided between these bands to form a local OFDM symbol in each sub-band using DHT. The global OFDM symbol is formed from all sub-bands together using

Circular thin walled structures have wide range of applications. This type of structure is generally exposed to different types of loads, but one of the most important types is a buckling. In this work, the phenomena of buckling was studied by using finite element analysis. The circular thin walled structure in this study is constructed from; cylindrical thin shell strengthen by longitudinal stringers, subjected to pure bending in one plane. In addition, Taguchi method was used to identify the optimum combination set of parameters for enhancement of the critical buckling load value, as well as to investigate the most effective parameter. The parameters that have been analyzed were; cylinder shell thickness, shape of stiffeners section an

Au nanoparticle-functionalized (TiO2)1−x(ZnO:MgO)x nanocomposite thin films (0≤x≤0.3) were effectively produced by chemical spray pyrolysis and annealed at 600 °C. The effects of ZnO incorporation and Au nanoparticle modification on the films' structural, optical, and antibacterial properties were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and field-emission scanning electron microscopy (FESEM). XRD analysis confirms the formation of polycrystalline anatase TiO2 and shows a composition-dependent structural development with increasing ZnO concentration. The optical experiments revealed increased transmittance and a progressive widening of the optical band gap from 3

Alloys from AgSb(SxSe1-x)2 with different compositions were prepared using quenching from the melt . This was done by put the appropriate amount of Ag, Sb,S and Se in an evaluated quartz ampoule , sealed and left at oven in temperature 1273 for 5 hours. Thin films with different composition were deposited by pulsed deposition technique PLD onto glass substrates at ambient temperature . This paper concerned on the investigate effect of composition on structural morphology, and electrical properties. The structure and morphology of the prepoared thin films were checked using X–ray diffraction and atomic force microscope. The D.C conductivity of the AgSb(SxSe1-x)2thin films with various x content was measured

Au nanoparticle-functionalized (TiO2)1−x(ZnO:MgO)x nanocomposite thin films (0≤x≤0.3) were effectively produced by chemical spray pyrolysis and annealed at 600 °C. The effects of ZnO incorporation and Au nanoparticle modification on the films' structural, optical, and antibacterial properties were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and field-emission scanning electron microscopy (FESEM). XRD analysis confirms the formation of polycrystalline anatase TiO2 and shows a composition-dependent structural develop- ment with increasing ZnO concentration. The optical experiments revealed increased transmittance and a progressive wid- ening of the optical band gap f

In this study, thin flms containing titanium dioxide (TiO₂), iron (III) oxide (Fe2O3) and cerium oxide (CeO2), with varying Fe2O3:CeO2 concentrations ranging from 0 to 30 wt% and 10 wt% gold nanoparticles (AuNPs), were prepared on glass using chemical spray pyrolysis. The structural, morphological, and sensing properties of the prepared thin flms were examined. XRD analysis revealed that a phase transformation occurred based on the dopant concentration: flms with x = 0 or 0.1 formed a polycrystalline anatase structure, whereas those with intermediate concentrations (x = 0.15 or 0.20) were amorphous. At higher doping concentrations (x = 0.25, 0.30), the structure developed a hematite Fe2O3, CeO2 and Au phase. Morphologicall

Hypothesis CO2 geological storage (CGS) involves different mechanisms which can store millions of tonnes of CO2 per year in depleted hydrocarbon reservoirs and deep saline aquifers. But their storage capacity is influenced by the presence of different carboxylic compounds in the reservoir. These molecules strongly affect the water wetness of the rock, which has a dramatic impact on storage capacities and containment security. However, precise understanding of how these carboxylic acids influence the rock’s CO2-wettability is lacking. Experiments We thus systematically analysed these relationships as a function of pressure, temperature, storage depth and organic acid concentrations. A particular focus was on identifying organic acid conce

Tin dioxide (SnO2) were mixed with (TiO2 and CuO) with concentration ratio (50, 60, 70, 80 and 90) wt% films deposited on single crystal Si and glass substrates at (523 K) by spray pyrolysis technique from aqueous solutions containing tin (II) dichloride Dihydrate (SnCl2, 2H2O), dehydrate copper chloride (CuCl2.2H2O) and Titanium(III) chloride (TiCl3) with molarities (0.2 M). The results of electrical properties and analysis of gas sensing properties of films are presented in this report. Hall measurement showed that films were n-type converted to p- type as titanium and copper oxide added at (50) % ratio. The D.C conductivity measurements referred that there are two mechanisms responsible about the conductivity, hence it possess two act