Engineering and Technology Journal

Porous silicon (PS) layers were formed on p-type silicon (Si) wafers by using electrochemical etching method. The influence of varying etching time in the anodizing solution ,on structural and optical properties of porous silicon has been investigated. Additionally , the thickness and porosity of the layers were measured using the gravimetric method. The surface morphology was studied by Scanning Electron Microscope (SEM). Finally, the optical properties of porous silicon on silicon substrates were investigated by employing photoluminescence (PL).

Indium Sulfide In2S3 window layer have been prepared by Chemical Spray Pyrolysis (CSP) at substrate temperate Equal (573 K) from Indium chloride and Thiourea were In/S ratio equal 1.2/8 in the spray solution, the samples prepared with different thicknesses (1.6, 1.7, 2.0 μm), the structural, optical and electrical of these films was investigated at different annealing temperature (Ta).X-ray diffraction studied shows the Structural properties of this layer are polycrystalline with preferred orientation 221, and have good improvement in the crystal structure at the annealing temperature (573K for 1h). The grain size increase with increasing annealing temperature and the optical band gap was found in the range (2.4-2.55 eV) as a function of the film thicknesses and the annealing temperature. Electrical studied of the sprayed and annealed sample shows n-type electrical conductivity, the mobility improved at the annealing temperature equal (573 K) but the resistivity decreased with this temperature.

Carbon nanoparticle was synthesis by pulse laser ablation of graphite target in different solution. Fourier Transform Infrared Spectroscopy (FTIR), Transmission electron microscopy (TEM) and Conductivity meter were used to study chemical composition, size, morphology and condectivity of suspensions. FTIR spectra exhibit the presence of C≡C, C═C, C-C bond which indicates the formation of carbon nanoparticles. The TEM show the formation of spherical nanoparticles, aggregation of the carbon nanoparticles, morphology of carbon nanotube ((141.6 nm length and 16.6 nm diameter) in ethanol, but high-quality of CNTs in Iso-propanol with (11.1–46.15 nm) diameter and (261.1- 592.3 nm) length and the CNTs are uniform diameters in deionize water with diameters (12.2-25 nm) and (500 - 708.3 nm) length). Study the electrical condectivity; determine the activation energy of suspension and the condectivity depended on geometry of carbon nanoparticles; electrical conductivity in ethanol suspension is more than Iso-propanol suspension and the electrical conductivity of deionize water is more than them.

Total Internal Reflection Microscopy has been employed to investigate Förster resonance energy transfer FRET for QD-dye conjugate system. QDs based donor systems are ideal for FRET for many reasons, one of them is that their broad excitation cross section which means that the direct excitation of the acceptor can be minimised via QD excitation at much shorter wavelengths, where little absorbance occurs in the acceptor. Förster resonance energy transfer (FRET) is a mechanism at which energy transfer between two fluorophores that occurs over a much shorter distance. A donor fluorophore in its excited state can transfer energy by a non- radiative, a long range dipole-dipole coupling mechanism to an acceptor fluorophore in close proximity (typically <10 nm). This is exactly the regime relevant to many biochemical processes and so significant effort has gone into developing FRET in recent years as a new tool for probing dynamics in condensed phase systems.

In this work, mixed oxide (TiO2-SnO2) thin films were grown on Si (111) and glass substrates by pulsed laser deposition (PLD) method. The influences of
increasing amounts of SnOR2R were investigated. The X-ray diffraction results show
the peaks position of the plane was shifted towards higher angle values with
increasing amounts of SnOR2R. The surface morphology of the deposits materials was
also studied by using a scanning electron microscope(SEM) The results show that,
the grain sizes decreases with increasing SnOR2R content from the largest value
(53.6)nm to smallest value (25.5) nm. From UV-visible spectroscopy, the distinct
variations in the transmission spectra, and optical energy gap, of the thin films
were also observed.

In the present work, Bismuth and Bismuth trioxide thin films were prepared using reactive pulse laser deposition technique. Different laser fluence was employed ranged from (1.8 J/cm2- 9.8 J/cm2) to investigatedthe physical properties. X –Ray diffraction result show a structure for the prepared films with monoclinic, tetragonal, and nonstoichiometric phases beside bismuth, while the atomic force microscopic result show grain size ranged from (33.48nm -131.6 nm) with different laser fluence. Optical properties result gave an energy gap value in the range of bismuth oxide (1.2-2.9 eV)

In this research, solar illumination is suggested to be used as an alternative to regular electrical illumination sources. Sunlight rays are collected, concentrated and transported through a system of light guide which distributes the sunlight to interior rooms. Schmidt Cassegrainin arrangement is used in the optical solar system design. Optical solar system consists of a tracking parabolic dish as a primary reflector, suggested to concentrate the solar rays on a secondary reflector, a cold mirror, which splits the solar spectrum into visible light which is reflected, directed into a plastic optical fiber cable, and infrared radiation which is transmitted away from the optical system to avoid melting the plastic optical fiber. An optimum optical design is attained by considering the optimum following parameters: applying different dish rim angles, different dish diameters and different dish reflector materials. Sun spot diameter to plastic optical fiber diameter ratio is a measure of geometrical compatibility of optimum transmitting solar light through the optical system.

Large amount of In-rich fibers are found on combinatorial deposited In-Y thin film. Sizes, morphologies, and distributions of fibers are most likely dependent on the film composition. Oxidation of the film seems to play an important role for the spontaneous formation of fibers. Demonstrate a potential application of combinatorial method to study fibers. Open a possibility for novel synthesis technique of one dimensional nanostructured materials. The results presented could be utilized as a new synthesis technique for one-dimensional nanostructured materials. The SEM results improve the direct and spontaneous formation of In micro-and nano-fibers

Microstructure imaging interpretation of polished surface has become well established as a method for the study of cement and concrete microstructure. This paper is an attempt to provide micro-level examination to the microstructure of cement paste in concrete particularly the hydrated mineral admixture and interfacial transition zone, which received increasing attention due to their effect on the hardened concrete properties. Furthermore, illustrations are provided of the transition area of cement paste adjacent to the aggregate border as well as other cement paste areas. SEM images reveal that pozzolanic reaction is not the only benefit of using mineral admixture. Spherical shape of grains is important to improve the microstructure of cement paste particularly in the interfacial transition zone

In this work, silver nanoparticles has been prepared via ablation of pure Ag metal target in distilled water was accomplished using Q-switched Nd:YAG laser at (1.06 μm) laser wavelength , with different laser energy and number of laser pulses. The effect of these parameters on the optical and surface morphology have been studied , UV-Visible show a red shift in the absorption spectra related to the shift in the energy gap due to increment of the grain of prepared particles size is increased as laser energy. Grain size of the obtained NPs are found to increase with laser energy with rang (20-112) nm as shown by the SEM result.

The multiwall Carbon nanotubes(CNTs) of 0.25wt %,0.5wt % and 1wt% was added to 0.1 M distilled aniline under reflex procedure with 0.3 H2SO4 for fabricating PANI/CNTs nanofibers. A cyclic potential ranged from -100 mV to 1500 mV was applied with six repetition on working electrodes stainless steel (SUS 304) which were dipped in these solutions at scan rate of 30mV s-1 at room temperature. Scanning Electron Microscope (SEM) images showed that the PANI-CNTs nanofibers structure with diameters range (50nm-70 nm). In the liquid type sensing, it was found that with the increase of HCl concentrations, the value of current density (J) could be raised and found pronounced at 3000 ppm and 4000ppm concentration along with PANI/0.5 wt %CNTs and PANI/1 wt% CNTs sensors out of the four corresponding four solutions and for sensors. The reason behind that may be the enhancement of more efficient transfer of charges. On the other hand a reduction in current density (J) was obtained with increasing concentration of NH3 and clearly observed at 1000 ppm and 2000 ppm for PANI/0.5 wt %CNTs and PANI/1 wt% CNTs sensors

The article reports fabrication, characterization and testing of the thermal stability of ZnO-based Schottky ultraviolet photodetectors. The ZnO thin film was grown on p-type Si ‹100 › substrate by sol-gel technique. The surface morphological and the structural properties of the thin film were studied by atomic force microscope (AFM) and scanning electron microscope (SEM). For the investigation of the surface chemical bonding, X-ray photoelectron spectroscopy (XPS) measurements were also performed. The I-V characteristics of the Schottky barrier photodetector were studied and the parameters such as ideality-factor, leakage-current, and barrier-height were extracted from the measured data at room temperature. With applied bias voltages in the range from -3V to 3V the contrast-ratio, responsivity, detectivity and quantum-efficiency of the photodetector were measured for an incident optical power of 0.1mW at 365nm wavelength. The electrical and optical study revealed that the performance of the device improves with increasing post metal deposition annealing temperature up to 100˚C. The device exhibited excellent thermally stability in the annealing temperature range of 100˚C to 200˚C. For annealing temperature beyond 200˚C the performance of the device degrades drastically. It was also found that under 200˚C there is a harmonious relation between the optical and electrical characteristics of the device. Above this annealing temperature there is no correlation between the variations of optical and electrical characteristics with increasing annealing temperature. The variation of the electrical and photoresponse properties of Schottky photodetector subjected to different post fabrication annealing can be attributed to combined effects of interfacial reaction and phase transition during the annealing process

In this study Bi2Te3 stoichiometry alloy was fabricated by using melting method in the electric furnce at temperature (580 0C for 6h). Thin films (Bi2Te3 ) were deposited by flash technique under vacuum 10-5 Torr . The thickness measured of films was 500nm .the influence of annealing temperature (100 -200) 0C was studied structure and optical properties of Bi2Te3 thin films. Structural properties for thin films of Bi2Te3 were investigated by XRD and AFM analysis. The XRD analysis of alloy show that poly crystalline phase for Bi2Te3 stoichiometry while the films prepared were amorphous at room temperature and phase transition to polycrystalline under annealing with preffered orientation at (015) corresponding to( 2θ =27.639) .FT-IR measured were studied for Bi2Te3 in range of (400-4000 )cm-1 under annealing temperature and this measured show that decreasing of Eg with increasing annealing temperature ,this can be interpreted in term improved the crystal structure

Composite structure of magnesia partially stabilized Zirconia (MgO-PSZ) with a Ni-Al bond coat have been investigated.This composite was sprayed on to a stainless steel grid of stainless steel-304 substrate to produce coating layer. The measurements of microstructure surface roughness, porosity and microhardness for sprayed layers wereperformed. PulsedNd: glass laser with pulse duration of 300 μs. and an energy ranging between (1-7.6)jouleswas used to investigate the effect of heat treatment on the sprayed layer.The laser treatment causeda reduction in surface roughness and porosity.An improvement in the mechanical properties of the composites wasobserved.

The use of nano alumina thin film by hybrid sol-gel route to protect steel from high-temperature oxidation is limited due to the low thermal stability of this coat. In this work, study has been conducted to minimize this effect. The chemical compositions of solid gel (xerogel) obtained from normal alumina hybrid sol-gel were thermally varied, and then recombining with water to form the modified coating solutions at constant concentration of 0.25mol/l alumina. Laser diffraction technique has been used to measure the growth of clusters sizes in different modified solutions. X-ray diffraction analysis to characterize the alumina phase's changes as a function of temperatures. Also gravimetric weight change method to determine the oxidation rate of steel before and after coating. The results showed five changes in alumina phase during heating to 9500C, which are similar to that recorded for the natural ore of boehmite, and the partial removal of non stable by-products constituents associated with xerogel has considerable effect on the degree of particles aggregation and agglomeration in solutions. This worked to improve the thermal stability of the coating layer, and show considerable resistance to cracks formation. At 40-50% removal, the oxidation rate of HSLA steel specimens was enhanced by 88 % at 9500C compared to the steel before coating.

Anew novel approach for synthesizing ZnO nano plate (ZNONPLs),ZnO nanowire, ZnO doped by Al, ZnO thin film by ALD on Indium Titanium Oxide(ITO) coated glass substrates for photovoltaic applications. The fabricated ZnO NPLs, ZnO , nanowire have been used to build bulk hetrojunction solar cells with blends of P3HT(poly(3-hexylthiophene) and PCBM((6,6)-phenyle C61 butyric acid methyl ester .Scanning electron microscopy, X-ray diffraction ,photoluminescence, UV-vis absorption spectroscopy, and photovoltaic measurements for studying morphology and device solar cells performance which prepared .The microstructure of the ZnO nanoplate ZNONPLs arrays plays two roles one for increase junction surface area and collecting the photo-generated electrons where has conducting paths to ITO glass .The Full factor ,and power conversion efficiency increased when using ZnO NW Modified by porphyrin

Nanocrystalline Copper Oxide films were deposited on glass substrates by plasma dc sputtering. The effected of discharge current on the structural and optical properties of sputtered films were studied .X-ray diffraction peak of Cu2O (111) and Cu4O3 (112) direction was observed at discharge current of (15-30) mA when annealed at 500 0C for 2 h. The optical energy gap for the prepared films is estimated to be in (2.05- 2.3) eV range. It was found that the effect of preparation conditions on thin films thickness strongly depends on the discharge current of argon plasma

We developed an organic-inorganic solar cell configuration based on nanocomposite Polyaniline-Multi Walled Carbon Nanotubes /gold particles/ Si, and the PV performance was compared between in presence or absence of plasmonics phenomena by deposing gold nanoparticles on n-type Si and deposited PANI-MWNTs layer on the top of n-type Si substrate. The gold particles deposited by atomic layer deposition on the top of n-Si, significantly increase the voltage and fill factor relative to devices without gold particles. The efficiency and fill factor of the solar cell with gold particles are (0.28%, 0.311) higher than solar cell without using plasmonics phenomena (0.073, 0.275).

The alkali metals make up first group of the periodic table. This family consists of the elements lithium, sodium, potassium, rubidium, cesium, and francium (Li, Na, K, Rb, Cs, and Fr, respectively).
The influence of alkali metals and its hydroxides supported on catalysts prepared SBA-15 for the synthesis of agro or biodiesel fuels from vegetable oil were investigated via heterogeneous catalytic reaction. The structural and textural features encapsulated Nanoporous Material SBA-15were studied by X-ray diffraction, scanning electron microscopy (SEM), EDAX, nitrogen adsorption-desorption (BET) and FTIR characterization were also carried out on the catalysts before and after loading. Mild conditions (atmospheric pressure and 65 ᴼC) were chosen for catalytic activity reaction testing in a batch reactor. The results show that all the catalysts were found active for the esterification reaction of vegetable oil conversion around (85-94%).
This study shows that the alkali metals and its hydroxides supported catalysts on SBA-15 based catalyst have proven to be a promising one for the transesterification of vegetable oil with methanol

In this research SnO2 thin films have been prepared by using hot plate atmospheric pressure chemical vapor deposition (HPCVD) on glass and Si (n-type) substrates at various temperatures. Optical properties have been measured by UV-VIS spectrophotometer, maximum transmittance about (94%) at 400 0C. Structure properties have been studied by using X-ray diffraction (XRD) , its shows that all films have a crystalline structure in nature and by increasing growth temperature from(350-500) 0C diffraction peaks becomes sharper and grain size has been change. Atomic force microscopy (AFM) uses to analyze the morphology of the Tine Oxides surface structure. Roughness & Root mean square for different temperature have been investigated. The results show that both increase with substrate temperature increase this measurements deal with X-Ray diffraction results, that there is large change in the structure state of SnO2 thin f film by changing temperature parameter

Cadmium Telluride (CdTe) thin films were prepared by thermal evaporation technique in the vacuum of about 3 × 10−3 mbar .using commercial glass substrates. The CdTe thin films were the effect gamma (γ) radiation on the grain size with dose
0.5μCi and membrane surface of treated films before and after to exposure period to
gamma radiation and characterized by X-ray diffraction (XRD) results showed that
the films are polycrystalline structure with hexagonal lattices and had preferred
growth of grains along the (002) crystallographic direction. Atomic Force microscopy
(AFM) and optical microscopic recognized. The optical band gap of thin films was
found to allow direct transition with energy gap of 1.7 eV.

ABSTRACT In this paper, azo dye polymer materials was synthesis from P-toludine with
Novolac by Fox method. The optical properties of an azo dye polymer film with
thickness 10μm have been investigated by the transmittance and absorbance spectra
in the wavelength range (300-900 nm). The linear optical parameters such as
refractive index (n) , extinction coefficient (k) , absorption coefficient (α) , real and
imaginary parts of dielectric constant were calculated. The optical energy gap was
estimated from the absorption coefficient using TaueP
,
Ps procedure. The oscillator
energy (ER0R), dispersion energy(ERdR) and the static refractive index (nRoR) have been
determined by the Wemple-DiDomenico method

A numerical study has been carried out to investigate the heat transfer by natural convection of nanofluid taking copper as nano particles and the water as based fluid in a three dimensional annulus enclosure filled with porous media between two horizontal concentric cylinders with 12 annular fins of 3mm length and 2.4 mm thickness attached to the inner cylinder under steady state condition and different wall temperature boundary conditions. The governing equations which used are continuity, momentum and energy equations under an assumptions used Darcy law and Boussinesq’s approximation which are transformed to dimensionless equations. The finite difference approach is used to obtain all the computational results using the MATLAB- 7. The parameters affected on the system are modified Rayleigh number (10 ≤Ra*≤ 500), radius ratio Rr (0.293, 0.365 and 0.435) and the volume fraction()3.00≤≤ϕ. The results show that, increasing of fin length decreases the heat transfer rate and for Ra*<100, decreasing Rr cause to decrease Nu and adding Cu nanoparticles with φ= 0.35 cause 27.9% enhancement in heat transfer. A correlation for Nu in terms of Ra, Hf and φ, has been developed for inner hot cylinder