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101.
R.M. Saleh J.M. Abd El Kader A.A. El Hosary A.M. Shams El Din 《Journal of Electroanalytical Chemistry》1975,62(1):297-310
The dissolution of Cu in solutions of HNO3 of different concentrations has been studied by the thermometric method. Starting from the initial temperature, Ti, the temperature—time curves exhibit an induction period followed by a rapid rise in temperature to a maximum value, Tm, attained t min after the start of the reaction. Tm increases and t decreases with increase of the acid concentration, M. ΔT (i.e.Tm ? Ti) and the reaction number (R.N. = (Tm ? Ti)/t) vary with M according to: ΔT = k(M ? M0) and R.N. = A1Mn, where k, M0, A1 and n are constants.The effect of varying concentrations of HCl, H2SO4 and H3PO4 on the R.N. of Cu in 3.5 M HNO3 was examined. Small amounts of these acids lower the R.N. (inhibition) due to the displacement of an active species on the surface of the metal by the anion of the acid. Larger additions of the acids accelerate dissolution. The concentration at which the added acid changes from corrosion-inhibitor to accelerator varies as HCl < H2SO4 < H3PO4. This sequence is considered to parallel the strength of adsorption of the respective anions. The results of experiments with salt additions confirm this view; all salts act only as dissolution-retardants. Calculations pertaining to the effect of the various ions on the R.N. support the conclusion that the dissolution of Cu in HNO3 is autocatalytic in nature, and depends on the [H+]/[NO3?] ratio.Cu does not dissolve in air-free, cold HCl. Attack takes place, however, in the presence of KNO3. Under these conditions attack is of the pitting- rather than the general type. The temperature rises suddenly after an incubation period, which decreases in length with increase of the amount of the added salt.Proof of the involvement of HNO2 in the autocatalytic cycle of Cu dissolution in HNO3 is obtained from the results of urea additions to the solution. 相似文献
102.
An electrochemical detector cell having a dropping-mercury working electrode and an Ag/ AgCl reference electrode is examined with reference to applications in flow-injection analysis and high-performance liquid chromatography. The working electrode, fed by a horizontal capillary, is capable of delivering mercury at fast dropping rates which can be varied by a control device in the cell. Examples of application to inorganic and organic electroreducible species are considered and advantages and limitations relative to other electrochemical detector devices are discussed. 相似文献
103.
104.
A new combination of Lie symmetry and Singular Manifold methods has been employed to study (3 + 1)-dimensional generalized Kadomtsev-Petviashvili (KP). Infinite-dimensional space of Lie vectors has been established. Single and dual linear combinations of Lie vectors are used after appropriate calculations of the arbitrary functions to reduce the equation to an ordinary differential equation (ODE). The resulting ODE is then analytically solved through the singular manifold method which resulted in a Bäcklund truncated series with seminal analysis leading to a Schwarzian differential equation in the Eigenfunction φ (η). Solving this differential equation leads to new analytical solutions. 相似文献
105.
Dynamic response systems are often found in science, engineering, and medical applications, but the discussion on experimental design for such a system is relatively rare in literature. For an experimenter, designing such experiments requires making decisions on (1) when or where to take response measurements along the dynamic variable and (2) how to choose the combination of experimental factors and their levels. The first consideration is unique for such experiments, especially when the measurement cost is high. In this paper, we present a design approach through the mixed‐effect linear model, which is based on a hierarchical B‐spline function for the dynamic response. We develop several theorems that can assist in finding a statistically efficient sampling plan and propose an algorithm for searching the D‐optimal design of a dynamic response system. 相似文献
106.
The variational iteration method (VIM) is applied to solve numerically the improved Korteweg-de Vries equation (IKdV). A correction function is constructed with a general Lagrange multiplier that can be identified optimally via the variational theory. This technique provides a sequence of functions with easily computable components that converge rapidly to the exact solution of the IKdV equation. Propagation of single, interaction of two, and three solitary waves, and also birth of solitons have been discussed. Three invariants of motion have been evaluated to determine the conservation properties of the problem. This procedure is promising for solving other nonlinear equations. 相似文献
107.
Ahmad Hussein Alomari Muneer Aziz Saleh Suhairul Hashim Amal Alsayaheen 《辐射效应与固体损伤》2013,168(3-4):294-306
ABSTRACTAs a pioneering study in Jordan, an extensive measurement for external gamma dose rate (GDR) was conducted. A portable gamma radiation detector was used to perform these measurements at 1?m above the soil surface. A geographical positioning system Garmin was used to record a total of 823 measured points. The GDRs’ measurement ranged from 35 to 470?nGy?h?1 giving a mean value of 90?nGy?h?1, which was found to be one and half times higher than the world average of 59?nGy?h?1. The lowest mean GDR 72?nGy?h?1 was found in the Albalqa governate, while the highest mean GDR 131?nGy?h?1 was found to be for the Alkarak governate. The mean annual effective dose was found to be 0.551?mSv, which is higher than the world average value of 0.48?mSv. This is a pivotal study evaluating the risks associated with GDR levels in Jordan that were the relative excess lifetime cancer risk, the mean collective effective dose, the mean weighted GDR and the mean lifetime dose that are 2.24?×?10?3, 5538manSv?y?1, 0.531?mSv and 39?mSv, respectively. The cosmic rays mean GDR was determined to be 20?nGy?h?1. This study focuses on constructing GDRs’ baseline data in Jordan, which will be used to determine the possible change in the natural radiation due to other human activities in the future. ArcGIS software was employed to generate an isodose map to characterise exposure rates caused by GDR in Jordan. 相似文献
108.
Waqed Hassan Ayad Faisal Enas Abed Nadhir Al-Ansari Bahaa Saleh 《Molecules (Basel, Switzerland)》2021,26(14)
The evaluation of groundwater quality in the Dammam formation, Faddak farm, Karbala Governorate, Iraq proved that the sulfate (SO42−) concentrations have high values; so, this water is not suitable for livestock, poultry and irrigation purposes. For reclamation of this water, manufacturing of new sorbent for permeable reactive barrier was required through precipitation of Mg and Fe hydroxides nanoparticles on the activated carbon (AC) surface with best Mg/Fe molar ratio of 7.5/2.5. Mixture of 50% coated AC and 50% scrap iron was applied to eliminate SO42− from contaminated water with efficiency of 59% and maximum capacity of adsorption equals to 9.5 mg/g for a time period of 1 h, sorbent dosage 40 g/L, and initial pH = 5 at 50 mg/L initial SO42− concentration and 200 rpm shaking speed. Characterization analyses certified that the plantation of Mg and Fe nanoparticles onto AC was achieved. Continuous tests showed that the longevity of composite sorbent is increased with thicker bed and lower influent concentration and flow rate. Computer solution (COMSOL) software was well simulated for continuous measurements. The reclamation of real contaminated groundwater was achieved in column set-up with efficiency of 70% when flow rate was 5 mL/min, bed depth was 50 cm and inlet SO42− concentration was 2301 mg/L. 相似文献
109.
M. Shaheer Malik Zaki S. Seddigi Shaik Bajee Shaik Azeeza Syed Riyaz Saleh A. Ahmed Ismail I. Althagafi Qazi M. Sajid Jamal Ahmed Kamal 《Journal of Saudi Chemical Society》2019,23(4):503-513
The versatility of multicomponent Biginelli’s reaction is exploited in the development of proline and cyclized cysteine tethered conjugates of monastrol, a kinesin Eg5 inhibitor. Ten new conjugates are synthesized focusing on structural replacement of the ester moiety (C-5 position) of the monastrol backbone with amino acid based amide moieties. On cytotoxic evaluation, conjugate 24 has shown promising in vitro cytotoxic activity against leukemia. Molecular docking studies revealed that the conjugates 19 and 24 exhibit better interaction at kinesin Eg5 receptor compared to monastrol. Moreover, computational calculations and predictions of important molecular properties suggest that these new amino acid based conjugates could be further improved to provide potential anticancer agents. 相似文献
110.
Ramandeep Behl Ali Saleh Alshomrani S. S. Motsa 《Journal of mathematical chemistry》2018,56(7):2069-2084
We have a good number of eighth-order iterative methods for simple zeros of nonlinear equations in the available literature. But, unfortunately, we don’t have a single iterative method of eighth-order for multiple zeros with known or unknown multiplicity. Some scholars from the worldwide have tried to present optimal or non-optimal multipoint eighth-order iteration functions. But, unfortunately, none of them get success in this direction and attained maximum sixth-order convergence in the case of multiple zeros with known multiplicity m. Motivated and inspired by this fact, we propose an optimal scheme with eighth-order convergence based on weight function approach. In addition, an extensive convergence study is discussed in order to demonstrate the eighth-order convergence of the present scheme. Moreover, we also show the applicability of our scheme on some real life and academic problems. These problems illustrate that our methods are more efficient among the available multiple root finding techniques. 相似文献