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Search Results: 1 - 10 of 801231 matches for " A. M. G.; "
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Alizarine Yellow R as Reagent of the Determination of Manganese by Extraction-Photometric Method  [PDF]
G. G. Abbasova, A. M. Pashajanov
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.610002
Abstract: 4,7-diphenyl-1,10-phenantroline from heterocyclic diamines and alizarine yellow R from chromogenic reagents have been used for spectrophotometric determination of manganese in the form of heteroligand manganese complex. The complex formation and extraction condition, physical-chemical and analytical characteristics of this complex have been established. 5.5 - 11.0 pH range is observed as complex formation pH range. Extraction and stability constants were accordingly found as Kext = 8.32 × 1014 and lgβK = 7.2 ± 0.1. Molar absorptivity is ε = (2.27± 0.08) × 104 l·g-1·cm-1. In the range of 0.5 - 23.0 μkg manganese (II) Beer’s law is obeyed. The extraction-photometric methods of manganese determination have been worked out. The strangers ions influence on determination of manganese (II) has been studied. To determine amount of manganese in eggplant the proposed method was applied successfully.
A Two-Stage Buccal Mucosal Graft (BMG) for Managing Recurrent Proximal Penile Hypospadias in Pediatric & Adolescent Populations  [PDF]
M. G. Elsheikh, A. Fayad
Open Journal of Urology (OJU) , 2011, DOI: 10.4236/oju.2011.11002
Abstract: Introduction: The presence of a recurrent proximal penile hypospadius represents a surgical challenge to the urologist due to the presence of excessive scarring and fibrosis of the tissues. This problem is more pronounced in circumcised patients, in whom there is no enough skin for one stage procedures. Buccal mucosal grafts represent a good surgical option. The aim of this study was to evaluate the results of two stages buccal mucosal urethroplasty in pediatric & adolescent patients, presenting with recurrent proximal penile hypospadias who are circumcised. Methods: Thirty seven pediatric & adolescent patients underwent two stages buccal mucosal urethroplasty for recurrent proximal penile hypospadius. In all cases the buccal graft was placed dorsally followed by the second stage closure after 6 months. Results: The mean age was 17.7 (14-20) years. With a mean follow-up of 28.3 months, 33 patients (89.2%) had a final successful outcome. Of the 4 cases that were considered as failure, 3 patients (8.1%) developed urethra-cutaneous fistula that required closure after 3 months. The remaining patient developed meatal stenosis. Conclusion: Although buccal mucosal urethroplasty is a two staged procedure, it is feasible option for pediatric & adolescent patients presenting with recurrent proximal penile hypospadius, who had no skin available for penile flaps, with a success rate approaching 89.2%.
Complex Bilding Behavior of 2 ((4-Methyl-5-Nitro-6- (Pyrolidine-1-yl)Pyrimidine-2-yl)Amino)Propionic Acid in Aqueous Solution  [PDF]
S. A. A. Sajadi, G. Bagherzadeh, M. Kermane, M. Khaleghian
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2013, DOI: 10.4236/ojinm.2013.31002
Abstract:

The acidity constants of MNPPAP1 were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+ or Zn2+ and MNPPAP2-, were determined by potentiometric pH titration in aqueous solution (I =0.1 M, NaNO3, 25). The order of the stability constants was reported. It is shown that the stability of the binary M(MNPPAP) complexes is determined by the basicity of the carboxyl or amino group. All the stability constants reported in this work show the usual trend. The obtained order is Ca2+ < Mg2+ > Mn2+ < Co2+ < Ni2+ < Cu2+ > Zn2+. The observed stability order for MNPPAP follows approximately the Irving-Williams sequence. It is shown that regarding to M ion-binding properties vital differences on complex bilding were considered. It is demonstrated, that in M-MNPPAP complexes, M ion is coordinated to the carboxyl group, M ion is also able to bild macrochelate over pyrimidine group. The up mentioned results demonstrate that for M-MNPPAP complex the stability constants is also largely determined by the affinity of M2+ for carboxyl group. It is shown that MNPPAP can exert a direct influence on reaction mechanism through different kinds of metal ions and donor groups of MNPPAP.

A Modified Formal Theory on Semi-Relativistic Effects during Electron Emission from Metallic Surfaces upon the Impact of High Energy Particles  [PDF]
S. Dhar, M. G. Hafez, A. Saha
Open Journal of Microphysics (OJM) , 2013, DOI: 10.4236/ojm.2013.34018
Abstract:

In this paper we introduce a formal theory on unveiling relativistic effects during electron emission from clean metallic surfaces upon high charged particle impact using a Jellium-type wave function including suitable spinors. In addition image charge final state electron surface interactions have been initiated in the relativistic region as well as the scattering of the projectile from the multi-center bulk potential. Finally, a semi-relativistic condition is considered in place of the ionization mechanism of scattering from an aluminium semi-infinite solid target by non-relativistic electrons to determine multiple differential cross-section.

Process Temperature Profile and Rheological Properties of Greases from Vegetable Oils  [PDF]
Leticia M. Lazaro, Donato A. G. Aranda
Green and Sustainable Chemistry (GSC) , 2014, DOI: 10.4236/gsc.2014.41007
Abstract:

Greases are composed by lubricating oil dispersed in a thickener that can be a metal soap, polymers or clays. Grease production using vegetable oils is increasing due to biodegradability requirements. Since vegetable oils present a worse oxidation and hydrolysis stability than mineral oils, it is usually difficult to produce a neutral grease using them. Four greases were produced using soybean oil as lubricating oil and lithium 12-hydroxy- stearate as thickener. The maximum temperature of reaction ranged from 230°C to 120°C in a bench process and a reduction in the final product acidity was observed (from 8.2% acid to 0.05% alkaline). Traditional tests to evaluate thickener structure resistance like 10,000-time worked penetration, roll stability and dropping point were performed and results compared. In addition, rheological tests were performed and the results were also compared. Results indicate that it is possible to produce a quite neutral grease using vegetable oils with good thickener structure properties.

Comparison of Rectangular and Elliptical Control Region EWMA Schemes for Joint Quality Monitoring  [PDF]
A. M. Razmy, T. S. G. Peiris
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.411091
Abstract: The exponential weighted moving average technique used in process mean and variance monitoring charts was combined by Gan in 1997 and proposed two combined joint monitoring schemes one with rectangular control region and the other with elliptical control region. Performance of these two schemes may very depend on the shifts in mean or variance to be detected quickly. In this paper, performances of these two schemes are evaluated with respect to the average run length properties. The results reveal that elliptical scheme is little faster in detecting the shifts in process mean and increase in variance within a limit.
The Effect of γ-Radiations on Dielectric Properties of Composite Materials PE + x vol% TlGaSe2  [PDF]
E. M. Gojayev, A. G. Hasanova
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2015, DOI: 10.4236/ojinm.2015.54006
Abstract: The purpose of the paper is to study the effect of gamma irradiation on the temperature dependence of the dielectric constant \"\"and dielectric loss (tanδ) of composite materials PE + x vol% (0≤ x ≤ 10). Measurements are carried out with an alternating current at a frequency of 1 kHz using the measuring bridge E-20. Measurements are carried out at temperature range 300 - 450 K, irradiated at doses of 50, 100 and 150 kGy. It is revealed that in all irradiated samples with increasing volumetric filler content increase the dielectric characteristics of composites PE + x vol%. TlGaSe2. Temperature variation of the dielectric parameters, after gamma irradiation are the result of occurring in the electron-ion and polarization at the interface of the matrix polymer with filler of TlGaSe2.
Coherent Resonance of Saturated Absorption in Spectroscopy of Counterpropagating Waves  [PDF]
A. A. Chernenko, E. G. Saprykin, A. M. Shalagin
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.45B010
Abstract:

Results of theoretical researches of the saturated absorption resonance shape in a method of the probing field on V-type of transitions are represented. It is shown that in case of opposite circulary polarized optical fields the resonance is shown in the form of cross, and its form strongly depends on relaxation constants of levels and it can be represented as in the form of a dip, and absorption peak. Thus the peak form has exclusively coherent character. Atomic transitions are offered, on which observation of the given effect is possible.

Fixed Point Theorems of Hegedus Contraction Mapping in Some Types of Distance Spaces  [PDF]
M. A. Ahmed, F. M. Zeyada, G. F. Hassan
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2012, DOI: 10.4236/ijmnta.2012.13013
Abstract: In the present paper, we prove some fixed point theorems of Hegedus contraction in some types of distance spaces, dislocated metric space, left dislocated metric space, right dislocated metric space and dislocated quasi-metric metric space which are generalized metrics spaces where self-distances are not necessarily zero.
Effect of Tubular Chiralities and Diameters of Single Carbon Nanotubes on Gas Sensing Behavior: A DFT Analysis  [PDF]
A. A. EL-Barbary, Kh. M. Eid, M. A. Kamel, H. M. Osman, G. H. G. H. Ismail
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2014, DOI: 10.4236/jsemat.2014.42010
Abstract:

Using density functional theory, the adsorption of CO, CO2, NO and CO2 gas molecules on different chiralities and diameters of single carbon nanotubes is investigated in terms of energetic, electronic properties and surface reactivity. We found that the adsorption of CO and CO2 gas molecules is dependent on the chiralities and diameters of CNTs and it is vice versa for NO and NO2 gas molecules. Also, the electronic character of CNTs is not affected by the adsorption of CO and CO2 gas molecules while it is strongly affected by NO and NO2 gas molecules. In addition, it is found that the dipole moments of zig-zag CNTs are always higher than the arm-chair CNTs. Therefore, we conclude that the zig-zag carbon nanotubes are more preferred as gas sensors than the arm-chair carbon nanotubes, especially for detecting NO and NO2 gas molecules.

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