FA1:La2+ and FA2:Sc2+ color center lasers and color image sensitization at the low coordination (0 0 1)surface of AgBr by ab initio calculations

A.S.Shalabi,I.A.Z.Al-Ansari,K.Kh.Al-Naimi,M.M.Shalaby,W.S.Abdel Halim 한국물리학회 2004 Current Applied Physics Vol.4 No.5

The role of type II FB (I):Tl+ defect in laser light generation and color image formation at the low coordination surface sites of AgBr: ab initio calculations

A.S. Shalabi,A.S. Algaber,N.K. Madi,Kh.M. Eid,Z.M. Fathy 한국물리학회 2006 Current Applied Physics Vol.6 No.1

The role of type IIFB (I):Tl+ color center at low coordination surface sites of AgBr thin lms in providing tunable laser activitystructure calculations. Clusters of variable sizes were embedded in simulated Coulomb elds that closely approximate the Madelungelds of the host surfaces, and ions that are the nearest neighbors to theFB defect site were allowed to relax to equilibrium in eachcase. The calculated Stokes shifted optical transition bands suggest that laser activity is relatively weak and fades quickly as thecoordination number of the surface ions decreases from 5 (at) to 4 (edge) to 3 (corner). An attempt has been made to explain thesesurfaces were deep below the lower edges of the conduction bands of the ground-state defect-free surfaces indicating that type IIFB(I):Tl+ is suitable laser defect. The probability of orientational destruction of the two centers, attributed to the assumed saddlepoint ion congurations along theh110i axis, was found to decrease as the coordination number of the surface ions decreases. Thepossibility of exciton (energy) transfer between sites of dierent coordination numbers was claried. The GlasnerTompkins empir-ical relation was generalized to include type IIFB (I):Tl+ doped surfaces. As far as photographic sensitization is concerned, a super-sensitizer increases the sensitizing capabilities of the two examined dye molecules by increasing the relative yield of quantumeciencyU.FA sensitizes the low coordination surface sites of the defect free AgBr by lowering the bottoms of the conductionbands. The dierence in the sensitizing capabilities between the two examined dyes was estimated by calculating the quasi Fermilevels.

A Performance Comparison between XEN and KVM Hypervisors While Using Cryptographic Algorithms

Mohammed Al-Shalabi,Waleed K. Abdulraheem,Jafar Ababneh,Nader Abdel Karim International Journal of Computer ScienceNetwork S 2024 International journal of computer science and netw Vol.24 No.1

Cloud Computing is internet-based computing, where the users are provided with whatever service they need from the resources, software, and information. Recently, the security of cloud computing is considered as one of the major issues for both cloud service providers CSP and end-users. Privacy and highly confidential data make many users refuse to store their data within cloud computing, since data on cloud computing is not dully secured. The cryptographic algorithm is a technique which is used to maintain the security and privacy of the data on the cloud. In this research, we applied eight different cryptographic algorithms on Xen and KVM as hypervisors on cloud computing, to be able to measure and compare the performance of the two hypervisors. Response time and CPU utilization while encryption and decryption have been our aspects to measure the performance. In terms of response time and CPU utilization, results show that KVM is more efficient than Xen on average at 11.5% and 11% respectively. While TripleDES cryptographic algorithm shows a more efficient time response at Xen hypervisor than KVM.

The novel polythiadiazole polymer and its composite with a-Al(OH)3 as inhibitors for steel alloy corrosion in molar H2SO4: Experimental and computational evaluations

Hany M Abd El-lateef,K. Shalabi,Abdelwahed R. Sayed,Sobhi M. Gomha,Esam M. Bakir 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

Polymer/composite materials have been commonly used as corrosion inhibitors in different fields such asmarine, oil field, and engineering industry due to their self-healing and thermal stability features. Herein,novel polythiadiazole, namely poly[(2,6-dicarbonylpyridine)(2,5-dihydrazinyl-1,3,4-thiadiazole)] (AMTP)via the interaction of 2,5-dihydrazinyl-1,3,4-thiadiazole with pyridine-2,6-dicarbonyl dichloride and itscomposite with a-Al(OH)3-gel were designed in a good yield. The structures of the fabricated materialsare characterized by FT-IR, NMR, SEM, and UV–Vis analyses. The protective action of AMTP and a-Al(OH)3@AMTP on the C1018-steel corrosion in molar-sulphuric acid was evaluated by potentiodynamicpolarization(PDP) and electrochemical impedance spectroscopic (EIS) methods. PDP findings presentedthat the AMTP polymer and a-Al(OH)3@AMTP composite performed as mixed-type inhibitors. The protectioncapacities of 90.3 and 97.6% were obtained in the presence of optimum dose 100 mg/L ofAMTP polymer and a-Al(OH)3@AMTP composite, respectively. The compound’s adsorption on C1018-steel follows the Langmuir isotherm model. The SEM/EDX outcomes reveal that the C1018-steel interfaceis inhibited by AMTP polymer and a-Al(OH)3@AMTP composite. DFT calculations exhibited that the efficiencyof the prepared materials correlates well with their electron contributing capability, whereas simulationsof Monte Carlo exposed that the favorability and extent of adsorption of additive moleculesmetal interface establish their corrosion protection routines.

Effect of β-Blocker Inhibitors on Aluminum Corrosion

Fouda, A. S.,El-Ewady, G. Y.,Shalabi, K. Korean Chemical Society 2011 대한화학회지 Vol.55 No.2

베타 차단제 억제제(atenolol, propranolol, timolol and nadolol)의 존재와 부존 하에서 0.1M HCl 용액에 담긴 알루미늄의 부식작용을 연구하였다. 이 연구에 무게감량, 변전위 편극, 전기화학 임피던스 분석법이 사용되었다. 억제 효과는 억제제의 농도 증가에 따라 증가하였으며, 온도가 증가함에 따라 감소하였다. 모든 억제제들은 Frumkin 등온을 따르는 알루미늄 표면에 흡착되었다. 부식반응은 전하이동과정에 의해 조절됨을 발견하였다. 억제 효과 측정을 위해 사용된 실험방법 들에 대해 조사한 결과 모두 억제효과가 우수하였다. Corrosion of aluminum in 0.1 M HCl solution in the absence and presence of ${\beta}$-blocker inhibitors (atenolol, propranolol, timolol and nadolol) was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency increased with inhibitor concentration and decreased with rise of temperature. Potentiodynamic polarization curves revealed that they acted as cathodic inhibitors. Some thermodynamic parameters were calculated and discussed. All inhibitors were adsorbed on Al surface obeying Frumkin isotherm. All EIS tests exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The inhibition efficiencies of all test methods were in good agreement.

Computational, kinetic, and electrochemical studies of polyaniline functionalized ZnO and ZnO-SiO2 nanoparticles as corrosion protection films on carbon steel in acidic sodium chloride solutions

May Ahmed Al-Masoud,Mai M. Khalaf,Ibrahim M. A. Mohamed,K. Shalabi,Hany M Abd El-lateef 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.112 No.-

Two novel nanocomposites based on polyaniline functionalized ZnO and ZnO-SiO2 nanoparticles(ZnO@PANi and ZnSiO@PANi) were synthesized, characterized, and evaluated as protective films for steelpipelines in the pickling process at 25–55 C. The prepared nanocomposites were described using differentspectroscopic characterization methods including UV–vis, FTIR, DLS, XPS methods, and other physicochemicaltechniques including XRD, FESEM, and HR-TEM. The novelty of these films is in the fact thatthe ZnO and ZnO-SiO2 nanoparticles are functionalized by polyaniline which is electrochemically stablein acidic solution and has high conductivity. Electrochemical systems such as open circuit potentials(OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) were utilizedto attain the kinetics and mechanistic findings of the corrosion protection route. The outcomes indicatethat the two fabricated ZnO@PANi and ZnSiO@PANi are efficient acidic corrosion inhibitors. Theprotection performance of ZnSiO@PANi (98.6%) was more pronounced at a dose (150 mg/L) thanZnO@PANi (92.3%) and individual PANi (83.4%) as achieved from PDP findings. The effect of temperatureand flowing conditions reinforces further the performance of both nanocomposites. Surface characterizationusing FESEM/EDS delivered more indication for the steel surface protection with the ZnO@PANi andZnSiO@PANi nanocomposites. Molecular modeling using DFT calculations and MC simulations supportedthe experimental findings. The binding energies of the compounds and Fe interface follow the order ofZnO@PANi > ZnSiO@PANi, which is in good agreement with the empirical results. An important suggestionof these results is the probability of substituting traditional toxic small molecules with cost-effectiveand non-toxic polymeric nanocomposites as protective films for use in the oil and gas industry.