Cairo University

MTPR Journal

 

A NEW TECHNIQUE FOR INCREASING EFFICIENCY OF SILICON SOLAR CELLS

U+1F512Silicon; Solar cells; V-shaped structure; Light confinement & doi: https://doi.org/10.1142/9789814317511_0012
A. IBRAHIM

A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the system is a V-shaped module (VSM) with two tilted monocrystalline solar cells. Compared to solar cells in a flat and tilted at a fixed 300 from horizontal orientation, the VSM enhances external quantum efficiency and leads to an increase of 30 to 35% in power conversion efficiency. Due to the VSM technique, short-circuit current density was raised from 25.94 to 34.7 mA/cm2, but both fill factor and open-circuit voltage were approximately unchanged. For the VSM similar results (about 35% increases) were obtained for solar cells fabricated by using mono-crystalline silicon wafers with only conventional background impurities.

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THE SOLAR SYSTEM IN THE AGE OF SPACE EXPLORATION

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0001
JAY M. PASACHOFF

We are celebrating the 50th anniversary of the launch of Sputnik, which began the space age. Though the manned exploration of the solar system has been limited to the Moon, in NASA's Apollo Program that ended over 35 years ago, robotic exploration of the solar system continues to be very successful. This paper explores the latest space mission and other observations of each planet and of each type of solar-system object, including dwarf planets, asteroids, and comets, as well as the sun.

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The Iron Project: RADIATIVE ATOMIC PROCESSES IN ASTROPHYSICS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0002
SULTANA N. NAHAR

Astronomical objects, such as, stars, galaxies, blackhole environments, etc are studied through their spectra produced by various atomic processes in their plasmas. The positions, shifts, and strengths of the spectral lines provide information on physical processes with elements in all ionization states, and various diagnostics for temperature, density, distance, etc of these objects. With presence of a radiative source, such as a star, the astrophysical plasma is dominated by radiative atomic processes such as photoionization, electron-ion recombination, bound-bound transitions or photo-excitations and de-excitations. The relevant atomic parameters, such as photoionization cross sections, electron-ion recombination rate coefficients, oscillator strengths, radiative transition rates, rates for dielectronic satellite lines etc are needed to be highly accurate for precise diagnostics of physical conditions as well as accurate modeling, such as, for opacities of astrophysical plasmas. for opacities of astrophysical plasmas. This report illustrates detailed features of radiative atomic processes obtained from accurate ab initio methods of the latest developments in theoretical quantum mechanical calculations, especially under the international collaborations known as the Iron Project (IP) and the Opacity Project (OP). These projects aim in accurate study of radiative and collsional atomic processes of all astrophysically abundant atoms and ions, from hydrogen to nickel, and calculate stellar opacities and have resulted in a large number of atomic parameters for photoionization and radiative transition probabilities. The unified method, which is an extension of the OP and the IP, is a self-consistent treatment for the total electron-ion recombination and photoionization. It incorporates both the radiative and the dielectronic recombination processes and provides total recombination rates and level-specific recombination rates for hundreds of levels for a wide range of temperature of an ion. The recombination features are demonstrated. Calculations are carried out using the accurate and powerful R-matrix method in the close-coupling approximation. The relativistic fine structure effects are included in the Breit-Pauli approximation. The atomic data and opacities are available on-line from databases at CDS in France and at the Ohio Supercomputer Center in the USA. Some astrophysical applications of the results of the OP and IP from the Ohio State atomic-astrophysics group are also presented. These same studies, however with different elements, can be extended for bio-medical applications for treatments. This will also be explained with some preliminary findings.

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RESOLVED FLUORESCENCE SPECTROSCOPY OF THE Cs2 33Πg → b3Πu TRANSITION

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0003
DAN LI, FENG XIE and LI LI

Perturbation facilitated Infrared-Infrared double resonance spectroscopy has been used to study the triplet states of Cs2. The 33Πg state has been observed and rotationally resolved fluorescence spectra into the b3Πu state and the perturbed A1Σu+ levels have been recorded. Molecular constants of the b3Π0u and A1Σu+ states were derived from the fluorescence spectra.

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EFFECTS OF RARE EARTH OXIDES ON SOME PHYSICAL PROPERTIES OF Li-Zn NANOPARTICLE FERRITES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0004
M. A. AHMED, N. OKASHA, A. I. ALI, M. HAMMAM and J. Y. SONG

The spinel ferrite Li0.2Zn0.6LayFe2.2-yO4; 0.01 ≤ y ≤ 0.1 were prepared by the usual ceramic sintering technique. XRD confirmed the formation of the samples in single phase spinel structure for all the samples. The lattice parameters decreased with increasing the La-content. The d c resistivity was measured as a function of temperature. The obtained results indicate the semiconductor like behavior, where more than straight lines indicating the presence of different conductions mechanism exist. The density of states near Fremi level as a function of La-content and discussed based on the variable range hoping model. The dielectric constant and dielectric loss were measured as a function of temprature and frequency. The dispersion peak at low frequency (10 kHz) was splitted by increasing La-content up to the suggested absorber splitting.

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A FIRST-PRINCIPLES CALCULATION OF THE MAGNETIC MOMENT AND ELECTRONIC STRUCTURE FOR SELECTED HALF-HEUSLER ALLOYS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0005
SAMY H. ALY, RIHAM SHAPARA and SHERIF YEHIA

Half-Heusler alloys are half-metallic magnets which may be defined as a new state of matter between insulating and metallic materials. These materials have many important applications in spintronics or magnetoelectronics devices. We have done first-principles (ab-initio) calculation of the magnetic moment and electronic structure for selected half-Heusler compounds. All the calculations were performed using the DFT-based electronic structure packages FPLO and WIEN2K. Half-metallicity (e.g. NiMnSb and RhVSb), semiconducting (e.g. FeVSb and NiVAl) and fully-metallic (e.g. NiVTe) behavior have been found in the compounds studied.

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A FIRST-PRINCIPLES CALCULATION OF THE ELECTRONIC STRUCUTRE, MAGNETIC MOMENT AND SPIN-DENSITY FOR SELECTED FULL-HEUSLER ALLOYS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0006
SHERIF YEHIA, M. M. AHMED, M. HAMMAM, MONA A. AHMED and SAMY H. ALY

Full-Heusler alloys are half-metallic materials which may be defined as a new state of matter between the insulating and metallic states. These materials have many important applications in spintronics or magnetoelectronic devices. We have done first-principles (ab-initio) calculation of the electronic structure, magnetic moment and spin density-maps for selected full-Heusler compounds. All the calculations were performed using the DFT-based electronic structure package WIEN2K. Half-metallicity (e.g. Co2Vga), nearly half metallic (e.g. Co2TiGa) and fully-metallic (e.g.Co2MnGa) behavior have been found in the compounds studied.

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MAGNETIC SUPER-EXCHANGE INTERACTION AND STRUCTURE OF COPPER(II) 1, 4 BUTYLENEDIAMINE TETRACHLORIDE [NH3(CH2)4H3N]CuCl4 SINGLE CRYSTAL

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0007
M.A. AHMED, I.S. AHMED FARAG and NABILAH M. HELMY

Butylene diamine copper tetrachloride was prepared in a form of crystal form from aqueous solution. X-ray of single crystal and magnetic properties studies were carried out, The structure of the neutral complex [NH3(CH2)4H3N]CuCl4 contains cationic [NH3(CH2)4H3N]2+ and anionic (CuCl4)2-. Results of X-ray revealed that the Cu atoms are 4-fold coordinated by chlorine atoms to form distorted square planer. The organic group is bonded with CuCl4 hydrogen bonds and Van der Waal contact. The temperature dependence of the magnetic susceptibility was measured in the temperature range from 70 to 500K at different magnetic field intensities. The results indicate that the complexes exhibit weak antiferromagnetic coupling between two metal ions.

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RESONANT TRANSFER EXCITATION CROSS SECTIONS FOR PHOSPHORUS IONS WITH K-SHELL EXCITATION

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0008
H. HANAFY, G. OMAR and F. SHAHIN

Resonant charge transfer and excitation (RTE) is an interesting process in ion-atom (I/A) collisions, which proceed through the formation of doubly-excited (d) states. If d-states stabilize by emission of x-rays, the sub-process is known as RTEX. This RTEX process is responsible for self cooling and ionization balance in thermal astrophysical and laboratory plasma. In fact, some intensive and extensive theoretical and experimental works have been done. However, many works still needed to understand the intricacies and the trends of this process for various isoelectronic and isonuclear sequences. The RTEX process in I/A collisions is identical to the dielectronic recombination (DR) in electron-ion (e/I) collisions. The DR and RTEX cross sections have been proved, Brandt (1983), that they are mathematically related. In the present work, The RTEX cross sections are calculated for the collision of P5+, 8+, 11+ ions with H2/He targets, in case of K-shell excitation. It is found that, the peak values of σRTEX are 2.58×l0-21 cm2, 2.82×10-21 cm2 and 3.02×10-21 cm2 at projectile energies 119.10 MeV, 118.13 MeV and 108.74 MeV for P5++H2, P8++H2 and P11++H2 collisions, respectively.

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INVESTIGATION OF THE DEVELOPED PRECIPITATES IN AlMgSiCu ALLOYS WITH AND WITHOUT EXCESS Si

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0009
E. F. ABO ZEID

The effect of temperature on the sequence of hardening precipitates in Al-1.15 Mg2Si-0.34Cu (wt %) balanced containing Cu and Al-1.14Mg2Si-0.34Cu balanced containing Cu with Si in excess alloys has been investigated by hardness measurement (HV), differential Scanning calorimetry (DSC) and Transmission electron microscopy (TEM) techniques. The values of the hardness number which corresponding to the hardening precipitated particles in the alloy containing Si in excess are higher than that in the alloy without Si. The results showed that, the difference in the hardening precipitation peaks positions may match the fact that, the excess Si increases the density of β‶ metastable phase and also, reduces the Mg/Si ratios in the early stage of GP zones and co-clusters formation. After the complete formation of the metastable needle shaped precipitates β‶ is taken place the strengthening of the alloy would take place as a result of the formation of the semi-coherent rod shaped precipitates β‵ and/or Q‵ phases.

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EVIDENCE OF JAHN-TELLER DISTORTION and PHASE SEPARATION IN Ca DOPED LaMnO3

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0010
M. A. AHMED and S. I. EL-DEK

A series of Ca doped LaMnO3 (La1-xCaxMnO3; 0.10≤x≤0.50) was prepared using conventional solid-state reaction. IR spectroscopic analysis was carried out for all samples. All investigated samples were ferromagnetic with the Curie temperature increasing with Ca content. The experimentally calculated values of the effective magnetic moment agree well with those computed theoretically. The largest value of the magnetic susceptibility as well as magnetic moment was achieved at x=0.30 pointing to a typical ferromagnetic character. The hysteresis which appeared in the magnetization during heating and cooling runs for the sample with x=0.30 enhances the choice of the sample x=0.30 as the optimum Ca content.

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ELECTRICAL CONDUCTION MECHANISM AND OPTICAL PROPERTIES OF POLYVINYL ACETATE AND CELLULOSE ACETATE PROPIONATE BLENDS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0011
F. H. ABD EL-KADER, A. M. SHEHAP, A. F. BASHA and N. H. EL-FEWATY

Films of Polyvinyl acetate (PVAc), cellulose acetate propionate (CAP) homopolymers and their blends of compositions 0.85/0.15, 0.7/0.3, 0.5/0.5, 0.3/0.7 and 0.15/0.85 (wt/wt) were prepared to investigate the type of electrical conduction mechanism. The current-voltage characteristics have been studied under different conditions. Also, ultraviolet/visible spectra of all samples have been studied according to their different composition ratios. The conduction mechanisms at different temperatures and voltage ranges appear to be essentially a space charge limited current for the two individual polymers, while for the blend samples the predominance mechanism is Poole-Frenkel type. Ultraviolet/visible studies of the investigated samples showed that the blend sample of 0.5/0.5 (wt/wt) has the smallest absorption edge (4.58 eV) and highest band tail (0.61 eV). The composition blend sample 0.5/0.5 (wt/wt) has the most proper conduction and optical properties which has attractive attention in the view of its application in electronic and optical devices.

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STUDY OF THE RELATIONSHIP BETWEEN ELECTRICAL AND MAGNETIC PROPERTIES AND JAHN–TELLER DISTORTION IN R0.7Ca0.3Mn0.95Fe0.05O3 PEROVSKITES BY MÖSSBAUER EFFECT

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0013
E. K. ABDEL-KHALEK, W. M. EL-MELIGY, E. A. MOHAMED, T. Z. AMER and H. A. SALLAM

In this work structural, magnetic and electrical properties of R0.7Ca0.3Mn0.95Fe0.05O3 (R= Pr and Nd) perovskite manganites are presented. Structural characterization of these compounds shows that both have orthorhombic (Pbmn) phase. The Mössbauer spectra show clear evidence of the local structural distortion of the Mn(Fe)O6 octahedron on the basis of non-zero nuclear quadrupole interactions for high-spin Fe3+ ions. It was found that the local structural distortion decreases significantly with replacing Pr3+ by Nd3+. This replacing dependence of the Jahn–Teller coupling strength estimated from the Mössbauer results was found to be consistent with the electrical and magnetic properties.

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ELECTRONIC BAND STRUCTURE AND MAGNETIC PROPERTIES OF YCo5

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0014
SAMY H. ALY, FATEMA ALZAHRAA HASSAN and SHERIF YEHIA

We present a first-principles study on the magnetic properties and electronic structure of YCo5 using the two well-known electronic structure packages FPLO and WIEN2k. Our results have been compared with the results of experiments and other ab initio calculations. The comparison shows a fair agreement between the present work and other published investigations.

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INFLUENCE OF ZINC SUBSTITUTION ON SOME PHYSICAL PROPERTIES OF Co-La FERRITE

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0015
M. A. AHMED and N. OKASHA

Co-Zn substituted ferrites with the formula Co1-xZnxLa0.025Fe1.975O4 with 0.1≤x ≤0.9 was prepared by conventional solid state reaction. X- ray diffraction (XRD), scanning electron microscope (SEM) and magnetic susceptibility (χ) are utilized in order to study the effect of variation in Zn content and its impact on crystal structure, magnetic properties such as (χ), Curie temperature (TC), and exchange interaction constant (J) between the different cations. The results of XRD reveal that, assured the single phase cubic spinel structure for all investigated samples with appearance of small peaks represented a secondary phase due to the presence of rare earth (La3+) ions. The particle size (t) varied with composition and heat treatment. The value of both TC and J decreases with increasing Zn content up to the critical concentration (0.5) then increases. The scanning electron micrographs indicate the distribution of grains in the sample with uniform size and agree well with the results of X- ray analyses. The influence of rare earth ions substitution on the structure and magnetic properties was examined.

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ROLE OF Cu2+ CONCENTRATION ON THE STRUCTURAL, SPECTROSCOPIC AND MAGNETIC PARAMETERS OF Y3+ SUBSTITUTED Ni-Zn FERRITE

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0016
M. A. AHMED, M. M. EL-SAYED and S. I. EL-DEK

The samples under investigation of the formula Ni0.7Zn0.3CuzY0.01Fe1.99-zO4; 0≤z≤0.1 were prepared using standard ceramic technique from pure analar oxides (BDH). IR spectroscopic analysis has been carried out for all samples. The magnetic susceptibility for the samples was performed using Faraday's method as a function of temperature and magnetic field intensities. The data were interpreted in view of the exchange interaction constant that takes place between the different cations. Variation of TC with Cu content in the samples was observed.

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EFFECTS OF RARE EARTH IONS ON THE QUALITY AND THE MAGNETIC PROPERTES OF Ag-FERRITES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0017
M. A. AHMED and N. OKASHA

A set of compounds with the formula MgAg0.4R0.2Fe1.4O4 where R is Lanthanum (La3+), Terbium (Tb3+), and Yttrium (Y3+), were prepared by the flash combustion technique. The effect of rare earths ions on some properties of silver doped was investigated. The obtained data indicated that, by introducing a relatively small amount of rare earths ions instead of Fe2O3 ions, an important modification of both the structure and the magnetic properties can be obtained. The Curie temperature, effective magnetic moment and exchange interaction are affected by these substitutions. The effect of rare earth ions were explained both by their partial diffusion in the spinel lattice and by the formation of the crystalline secondary phase on the grain boundaries.

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VACUUM TECHNOLOGY AND STANDARDIZATION-AN UPDATE

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0018
H. M. AKRAM and H. RASHID

Vacuum technology has been vital for the progress in almost every field of modern industrial & scientific research and technological developments. Research in this field is therefore important for the rapid progress in other sophisticated technologies. The modern society require precise know-how of vacuum metrology for its complex and sophisticated manufacturing processes and research activities. Accuracy in vacuum measurements is therefore an essential need for every application. The required accuracy is achieved with the help of well-calibrated vacuum gauges and this is possible only, if there exist proper vacuum standards of required range and accuracy. In this paper, a brief review of recently developed different vacuum standards, namely Standard Mercury Manometer, Standard Volume Expansion System and Standard Orifice Flow System will be presented, employed for the calibration of low, medium and high vacuum gauges respectively. Our recently developed standards are simple in design, least in vibration & degassing rate with desired accuracy, ease of operation and cost effective.

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THE INTERACTION OF HIGH DENSITY SHORT PULSE LASER WITH MATTER

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0019
LOTFIA EL NADI and MAGDY M. OMAR

The study of the interaction of High Density Short Pulse (HDSP) lasers with matter is an important rapidly expanding branch of Physics. Since 1985 these lasers have been developed to generate very short pulses with typical high performance parameters: peak powers up to hundreds of TW, pulse duration less than 20 fs, pulse energy more than 2J, repetition rate up to 10 Hz and wavelength of 800nm that could be lowered through higher harmonic generation. When such photons are properly focused on a target, creation of simultaneous unprecedented conditions in the laboratories within very short time takes place, namely: brightness up to 1020 W/cm2, electric fields up to 1011 V/cm, magnetic fields up to 109 gauss, temperatures of the order of 1012 °K, pressures ~109 bars and acceleration of up to 1026cm/s2. These conditions could definitely initiate severe nonlinearities within the exposed materials. The main objective of this paper is to review the studies on particle generation, particularly neutrons, by the interaction of high intensity lasers with solid or gas targets. Then propose their possible applications.

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ELASTIC BACKSCATTER LIDAR SIGNAL TO NOISE RATIO IMPROVEMENT FOR DAYLIGHT OPERATIONS: POLARIZATION SELECTION AND AUTOMATION

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0020
YASSER Y. HASSEBO and KHALED ELSAYED

Signal-to-Noise Ratio (SNR) improvements is one of the important issue in lidar measurements, particularly for lidar daytime operations. Skylight background noise precincts lidar daytime operations and disturbs the measurement sensitivity. In the past, polarization selective lidar systems have been used mostly for separating and analyzing polarization of lidar returns for a variety of purposes. A polarization discrimination technique was proposed to maximize lidar detected SNR taking advantage of the natural polarization properties of scattered skylight radiation to track and minimize detected sky background noise (BGS). In our previous work this tracking technique was achieved by rotating, manually, a combination of polarizer and analyzer on both the lidar transmitter and receiver subsystems, respectively. Minimum BGS take place at polarization orientation that follows the solar azimuth angle, even for high aerosol loading. In this article, we report a design to automate the polarization discrimination technique by real time tracking of the azimuth angle to attain the maximum lidar SNR. Using an appropriate control system, it would then be possible to track the minimum BGS by rotating the detector analyzer and the transmission polarizer simultaneously, achieving the same manually obtained results. Analytical results for New York City are summarized and an approach for applying the proposed design globally is investigated.

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ANALYSIS OF PLASMA PRODUCED BY LASERABLATION FOR COPPER

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0021
A. I. REFAIE, I. EL GHAZALI, S. H. ALLAM and Th. M. EL SHERBINI

A time-resolved diagnostic technique was used to investigate the emission spectra from the copper plasma produced by the high power Q-switched Nd : YAG laser that generates 670 mJ pulses in 6 ns of duration at a frequency 10 Hz and 1064 nm pulse-laser ablation in air. Spectroscopic measurements were devoted to determine the plasma temperature by using Boltzmann plot for the spectral lines of Cu I which are free from self-absorption. Electron number density was also deduced from the stark broadening measurements for different delay times (0.5-10 μs) under the assumption of local thermodynamical equilibrium (LTE). Branching ratios for the some experimental relative transition probabilities have been determined. Calculations with a relativistic Hartree-Fock wavefunctions have been carried out for Cu II in order to place the experimental data on an absolute scale. The Results are compared with that measured and with the available data in literature.

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PREPARATION OF GaN NANOSTRUCTURES BY LASER ABLATION OF Ga METAL

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0022
LOTFIA EL NADI, MAGDY M. OMAR, GALILA A. MEHENA and HUSSIEN M. A. MONIEM

In the present study, GaN nanodots (0D) and nanowires (1D) nanostructures were prepared on stainless steal substrates applying laser ablation technique. The target of Ga metal mixed with NaNO2 was introduced in a central bore of a graphite rod of a confined geometry set up. The laser beam was normally focused onto the central bore and the ablated plume of Ga metal was deposited on stainless steal substrate lying below the graphite rod in an atmosphere of slow flow of nitrogen gas with or without ammonia vapor. The pulsed N2 laser beam having a wavelength of 337± 2 nm, pulse duration 15±1 ns and energy per pulse of 15±1 m J, could be focused on the central bore by a cylindrical quartz lens to a spot of dimensions 500 × 700 μm2 t providing target irradiance of 0.2-0.3 GW/cm2 per pulse. The ablated plum was collected after several thousand laser shots. The morphology and structure of the formed nanostructures were investigated by Scanning electron microscope and Energy Dispersive X-Ray Spectroscopy. The growth mechanism is most likely by Solid-Liquid-Vapor phase during the laser ablation processes. The role of the carbon, the NaNO2 and the flowing gas on the growth of Nanostructures of GaN are discussed.

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LASER-INDUCED BREAKDOWN SPECTROSCOPY TECHNIQUE IN IDENTIFICATION OF ANCIENT CERAMICS BODIES AND GLAZES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0023
KHALED ELSAYED, HISHAM IMAM, FATMA MADKOUR, GALILA MEHEINA and YOSR GAMAL

In this paper we report a study on Laser Induced Breakdown Spectroscopy (LIBS) as a promising non-destructive technique for the identification of the colored glazes, and clay's bodies of Fatimid ceramics ancient artifacts. The scientific examination of ceramics may be helpful in unraveling the history of ancient shards, particularly as the process of its production such as firing condition and temperatures. The analysis of pottery, ceramic bodies and glazed coatings is required in order to structure the conservation or restoration of a piece. Revealing the technical skills of ancient potters has been one of the most important issues for gaining a deep insight of bygone culture and also it is required in order to structure the conservation or restoration of a piece of art. LIBS measurements were carried out by focusing a Nd-YAG laser at 1064 nm with pulse width of 10 ns and 50 mJ pulse energy on the surface of the sample by a 100-mm focal length lens. The plasma emission was collected by telescopic system and transferred through a fiber to Echelle spectrometer attached to an ICCD camera. The focal spot diameter is found to be in the range of 100-150 μm. which is small enough to consider this technique as a non-destructive technique. LIBS technique clarified that each piece of archaeological objects has its own finger print. X-ray diffraction (XRD) analysis was carried out on these archaeological ceramic body samples to study raw materials such as clays, which allowed the investigation of the crystal structure and showed the changes in its structure through firing process. This provided information on the ceramic characteristic and composition of the ceramic bodies.

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THERMAL STABILITY AND INFRARED-TO-VISIBLE UPCONVERSION EMISSIONS OF Er3+/Yb3+ CO-DOPED 70GeO2-20PbO-10K2O GLASSES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0024
SAMAH M. AHMED, I. SHALTOUT and Y. BADR

Er3+/Yb3+ co-doped potassium-lead-germanate (70GeO2-20PbO-10K2O) glasses with a fixed concentration of Er3+ ions (0.5 mol. %) and different concentrations of Yb3+ ions (0, 0.5, 1.5, and 2.5 mol. %), have been synthesized by the conventional melting and quenching method. The structure and vibrational modes of the glass network were investigated by the infrared absorption and Raman spectroscopy. The thermal behavior of all glass samples was investigated by the differential thermal analysis. Infrared-to-visible frequency upconversion process was investigated in all glasses. Intense green and red upconversion emission bands centered at around 532, 546, and 655 nm were observed, underallglasses.Intense excitation at 980 nm of diode laser at room temperature. The dependence of these emissions on the excitation power was investigated.

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EFFECT OF HOST MEDIUM ON THE FLUORESCENCE EMISSION INTENSITY OF RHODAMINE B IN LIQUID AND SOLID PHASE

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0025
M. FIKRY, M. M. OMAR and LOTFI Z. ISMAIL

In this work, we study the effect of concentration, host medium, PH, ions complex and phase states on the fluorescence emission from the laser dye, Rhodamine B, pumping by UV laser as exited source. The polymethylmethacrylate PMMA used as host medium in case of solid phase samples while, ethanol and Tetrahydrofuran (THF) are used in case of liquid one. The Laser Induced Fluorescence (LIF) technique was used to study the fluorescence properties of the both cases liquid and thin film solid-state samples. In addition, the Dual Thermal Lens (DTL) technique was used to study the quantum yield of these samples. The maximum fluorescence emission observed at concentration of Rhodamine B C=3×10-4M. At this concentration of Rhodamine B, the type of solvent and polarity of the medium affect on the fluorescence emission intensity of Rhodamine B with. The measurements revile that, the behavior of both phases state was analogous and Rhodamine B/PMMA thin film sample by ratio of 4:1 and thickness 0.12 mm is the best photostability sample and its quantum yield about ≈ 0.82. Also, the fluorescence emission intensity of Rhodamine B was quenched by complex formation of Co, Al, Cu and iodide ions with Rhodamine B due to the increase of the charge density of the ions.

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LOW TEMPERATURE PHOTOLUMINESCENCE AND PHOTOCONDUCTIVITY OF ZnSexTe1-x TERNARY ALLOYS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0026
A. SALAH, G. ABDEL FATTAH, I.K. ELZAWAWY and Y. BADR

We investigated Low-Temperature Photoluminescence (PL) spectra of ZnSexTe1-x were grown from the melt where 0≤x≤0.202, the spectra of ZnSexTe1-x showing a broad band which may be attributed to self activated emission, The broad self activated (SA) emission band have been assigned to various crystalline defects, such as dislocations and vacancies or their combination with impurities. The room temperature photoelectric response spectra of ZnSexTe1-x samples (0≤x≤1) were measured, a single band was observed in the band edge region which attributed to the generation of more number of free charge carriers in the band gap region. The relaxation time was determined from studying the kinetics of photoconductivity

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OPTICAL PROPERTIES OF Ga OXIDE NANOSTRUCTURES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0027
LOTFIA EL NADI, GALILA ABDELATIF, HUSSEIN M. MONIEM and MAGDY M. OMAR

Gallium oxide nanodots of diameter 300 to 220 nm have been grown by SiO2 assisted thermal evaporation. The formed grayish white crust deposited on the crucible walls was proved to be crystalline Ga2O3 through X-ray diffraction and TEM electron diffraction. The morphology of the samples examined by SEM, confirmed the nanodot structure formation of averag diameter 220 ± 30 nm and average density of 1.77×108 cm-2. The absorption spectra of the Ga2O3 suspension in DMF solution revealed two absorption peaks at 329.99nm (3.76 eV) and 338.60 nm (3.67 eV). Photoemission of blue light at room temperature was observed at 410.3 nm with FWHM 56.7 nm under excitation by 330.00 nm. The growth mechanism of the nanodots is explained in terms of liquid-vapor-solid mechanism (LVS). The remaining hard ingot was found to have 16.6 Vicker's hardness. The silicon glass having the value of Vicker's hardness 15 indicates that the ingot material is 10 % harder than that of glass.

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A COMPARATIVE STUDY OF LASER CLEANING OF ARCHAEOLOGICAL INORGANIC MATERIALS WITH TRADITIONAL METHODS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0028
HISHAM IMAM, KHALED ELSAYED and FATMA MADKOUR

Ancient artifacts excavated from archaeological site were covered with different soil contaminates and stains which changed their chemical composition and aesthetic appearance. Ancient inorganic materials such as bronze, glass and pottery covered with different contaminates such as corrosion products, soil deposits, organic stains and gray white encrustations. Lasers are currently being tested for a wide range of conservation applications. Since they are highly controllable and can be selectively applied, lasers can be used to achieve more effective and safer cleaning of archaeological artifacts and protect their surface details. In the present work we investigated in a general way the laser cleaning of bronze corrosion products, glass, and pottery by Q-switched Nd:YAG Lasers. The results were compared with conventional methods. The artifact samples were examined by Light Optical Microscope (LOM) and showed no noticeable damage.

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ASTHMA EARLY WARNING SYSTEM IN NEW YORK CITY (AEWSNYC) USING REMOTE SENSING APPROACHES

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0029
YASSER HASSEBO and ZAHIDUR RAHMAN

Asthma is estimated to affect approximately 17.3 million Americans, including 5 million children less than 18 years of age. Of these 5 million children, 1.3 million are less than 5 years of age. Asthma is a major public health problem in NYC particularly in Bronx. 12.5% of new Yorkers have been diagnosed with asthma. 300,000 children in NYC have been diagnosed with asthma up to year of 2000. NYC children were almost twice as likely to be hospitalized due to asthma attacks as the average of US child in 2000. Queens county's diesel pollution risk ranks as the 10th unhealthiest in the US compared to over than 3000 counties. Asthma symptoms are consistent with exposure to a high level of a respiratory irritant gas, smoke fume, vapor, aerosol, particulate matter (PM10 and PM2.5), and dust. Some types these environmental gaseous such as sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) can exacerbate preexisting respiratory symptoms in the short-term. Control of air pollution related diseases such as asthma, cancer, and bronchitis is difficult and inefficient due to the uncertainty in the air pollution transportation. Asthma control relies on air pollution detection and reduction. Asthma control can be improved by applying spatial tools such as Remote Sensing (RS), Geographical Information Systems (GIS). The project long-term goal is to develop a model to predict an Asthma Early Warning System for NYC (AEWSNYC), using two approaches: (1) satellite data error correction collaboratively with (2) Ground-based multiwavelength lidar measurements and NASA back trajectory tools. The proposed method can be used to create an efficient asthma control model globally.

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DO WE EXPECT A MULTIPLE DIP STRUCTURE AT LHC ENERGIES?

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0030
FAZAL-E-ALEEM, HARIS RASHID and SOHAIL AFZAL TAHIR

Besides other parameters, measurements are also planned for differential cross section at Large Hadron Collider (LHC). Shrinkage of the diffraction peak and dip structure in the differential cross section are amongst the agenda of measurements at TOTEM Experiment. Many theoretical models predict multiple dip structure at LHC energy. We briefly review the status of shrinkage phenomena and possibility or otherwise of a multiple dip structure in the light of Geometrical models. A comparison has been made with the predictions of other models. We have also undertaken the role of rho (ρ) in the appearance or otherwise of multiple structure. In order to have a better understanding of the evolution of dip structure, we will also include the measurements from PP2PP at RHIC.

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SEARCH ON e+ - e- PAIR AND OBSERVATION OF A NEW LIGHT NEUTRAL BOSON

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0031
M. S. EL-NAGDY, A. ABDELSALAM and B. M. BADAWY

We present a unified description of e+ e- dilepton production in heavy ion collisions at relativistic (3.7A GeV) and ultrarelativistic (200A GeV) energies. From the interactions of [12C and 22Ne] at 3.7A GeV and 32S at 200A GeV with nuclear emulsion, 134 e+ e- pairs are observed. The differential distribution of the energy asymmetry of pairs is compared to a background observation at Bristol. The events are consistent in a way that, they scale well in a single curve of exponential decay. This ensures correct asymptotics and provides a unified description of mesonic decay. The existence of light neutral boson of mass (1.55±0.14 MeV/c2) is questionable, because the candidate peak is seen in the invariant mass spectrum of its decay into e+ e- pairs. The data seem to suggest the production and subsequent decay of short lived neutral boson with lifetime of the order of 10-16 S.

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THE MOVING QUASARS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0032
SHAHINAZ YOUSEF, M. KAMAL, H. MANSOUR, SAYEDA, M. AMIN, KHADIGA ABDER RAHMAN and AL HASSAN ABD AL MONEM

Quasars, those very far objects with very high proper motions implying that their transverse velocities far exceed the velocity of light. Their space velocities are superluminal and are within a fraction of a degree from their transverse velocities. We propose that QSOs form a cloud that envelopes the cosmos. We refer to this cloud as Al Tareq Cloud. The jets although mildly superluminal may force the QSO forward opposite to the jet ejection direction. Jets also help in changing the moving direction of the QSO. In other words, jets help in speeding up and maneuvering the QSO. There are tw belts of Quasars; The inner Quasar Belt at Z= (0.25-0.4) and the Outer Quasar Belt at Z = (1.8-2.25). From the present Quasar study, there is an indication that the preliminary age of the universre is of the order 46-49 Gyrs.

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ELECTRON BEAM TECHNOLOGY – SOME RECENT DEVELOPMENTS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0033
MUNAWAR IQBAL and FAZAL-E-ALEEM

Electron beam technology has been in focus since long due to wide variety of applications in research and industry. One of the important modes of e-beam production is through thermionic emission. Improvements and advancement in enhancing the capabilities of electron beam sources compatible with the task to be accomplished at a reduced cost are therefore necessary. We give an update of the recently developed and reported e-guns which are easy to fabricate, assemble and more efficient. Besides being cost effective, these guns are user friendly.

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STUDY OF TARGET FRAGMENTATION IN HEAVY ION INTERACTIONS AT 3.7A GeV

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0034
A. ABDELSALAM, N. RASHED, B. M. BADAWY and E. EL–FALAKY

We report the experimental measurements of the multiplicity and angular distributions of the target associated particles (grey and black) produced in the interactions of (p, 3He, 4He, 6Li, 12C, 22Ne, and 28Si) with emulsion nuclei at nearly the same incident energy (3.7A GeV). The average values of the emitted grey and black particles increase with increasing target size. They are found to be dependent on the impact parameter of the interaction. The multiplicity and angular distributions reach asymptotic behavior with anisotropy factor (F/B)g,b. This factor seems to be independent of the projectile and target masses as well as the impact parameter. The experimental angular distributions are analyzed in the framework of the modified Maxwell – Boltzman distributions. The results yield quite interesting information regarding the mechanism of target fragments production in the backward hemisphere. The (F/B)g,b ratios are good parameters to calculate the temperature of the systems emitting grey and black particles.

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SOLAR INDUCED CLIMATE CHANGES AND COOLING OF THE EARTH

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0035
SHAHINAZ M. YOUSEF

Evidences are given for the cooling effect induced by solar weak cycles. It is forecasted that the coming solar cycle number 24, which has started on January 2008, would be very weak. This cycle would be followed by several weak cycles. Its very start on January 2008 have induced a climate change that forced global cooling, Indeed all global temperature monitors have shown temperature drops. The GISS monitor showed a 0.75°C drop between January 2007 and January 2008. This sharp temperature drop characterizes cooling induced by weak cycles as was evident by historical temperature records. It also happened in the right exact timing of the start of cycle 24. This cooling is real and could last for some time. The cooling well width is location dependant. Last January cooling left many countries in deep freeze. Cooling is very serious and can destroy crops and cause famines. This cooling is instrumentally recorded. This is an appeal to scientists to consider the present cooling seriously, after all the truth ought to be followed. Alert is also given to the reaponsible authorities to work promptly to choose the proper crops that can tolerate the cold otherwise it would be a disaster worldwide.

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CROSS-SECTIONS CALCULATIONS FOR PRODUCING PAIR HIGGS BOSONS AND NEUTRALINO VIA THREE NEUTRAL HIGGS BOSON PROPAGATORS

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0036
M. M. AHMED

The production cross-sections calculations for the process . Where represent the three neutral Higgs bosons, are calculated through all the allowed modes of interactions. Which are (1296) situations are consider in two different groups of Feynman diagrams are taken into account. (1) Production of from and Z0 propagators exchange (from 1-864 Feynman diagrams). (2) Production of from propagators and the neutralino is leg (from 865-1296 Feynman diagrams). where (i, j = 1,2,3, and ℓ = 1,2,3,4) The values of the cross sections σ are taken as a function of the incident center of mass energy S. The values of the cross-sections have greatest values at S ranges from 3000 to 3400 GeV., and the against cross section is from rang 2.5 × 10-10-4 × 10-10, and the best calculations have numbers from 865-1080, where the production mechanisms can be detected in mode when the neutralino is leg from positron.

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THE PRODUCTION CROSS-SECTIONS FOR THE PROCESS formula e+ (P1) +e-(P3) -> H+2<(P2) + H-2(P4)+X02(P5)

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0037
M. M. AHMED, M. H. NOUS, SHERIF YEHIA and A. A. ASMAA

The cross-section, in electron (e-) positron (e+) collision, are calculated over range of center of mass energy for the process. Four different group of Feynman diagrams are taken into consideration depending on the type of the propagator: i - Production of χ0 and H± when z0 and H0 are the propagators exchange. ii - Production of χ0 and H± when χ0 is a leg from electron or positron, and γ is the propagator. iii - Production of χ0 and H± when χ0 is a leg from electron and positron, and Z0 is the propagator. iv - Production of χ0 and H± when χ0 is a leg from electron or positron, and H0 is the propagator. Where (i, j = 1,2,3, and = 1,2,3,4) The cross section for each group is calculated according to a carefully selected set of parameters. These different possible (1155) situations are graphed and tabulated. The production mechanisms can be detected as:

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AN EARLIER NATURAL MECHANISM PROPOSAL FOR THE CLOSURE OF THE OZONE HOLE AND THE PRESENT 30% CLOSURE

U+1F512 & doi: https://doi.org/10.1142/9789814317511_0038
SHAHINAZ M. YOUSEF, SIHAM A. AL-KUHAIMI and AISHA BEBARS

A prolonged period of reduced solar activity of the order of few decades is expected owing to the presence of weak solar cycles series like those around 1800 and 1900 AD. Reduced UV flux is forecasted. The multitude of phytoplanktons in the Antarctic Ocean which are harmed by excessive UV passing through the ozone hole are expected to recover owing to the reduced solar UV doze even with the existence of ozone hole. An increase of only 10% of the phytoplankton would remove about 5 Gigatons of carbon dioxide from the atmosphere annually (which is equal to the amount of carbon dioxide emitted currently by fossil fuel utilization) and sink it into the ocean. Reduction of carbon dioxide from the atmosphere will lead to cooling of the troposphere and hence warming of Antarctic stratospheric clouds which are the sight of ozone destruction. Eventually, this procedure will hopefully lead to Antarctic ozone hole closure. The paper also discuss the implication of the 1997 solar induced climate change on the appearance of the Arctic ozone hole and the reduction of the Antarctic ozone hole. Anther more serious solar indsolarinduced climate change is currently on due to the end of the first weak solar cycle number 23 and the start of predicated second weaker solar cycle number 24. A climate change, which has already brought global cooling to the earth. The Ozone hole has been closed by 30% in 2007 as prdicted which a triumph is for the subject of sun-Earth connections. It is also predicted that further closures in the coming few years will occur due to solar induced climate changes. The forecast of the ozone hole closure was predicted in earlier papers.

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