Spectrophotometric determination of Fe(III) with tiron in the presence of cationic surfactant and its application for the determination of iron in Al-alloys and Cu-based alloys

A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (41) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 g/ml with an average molar absorptivity of 15800 l mol^–1 cm^–1. The molar ratio as determined by Job's method for Fe:tiron:CPC is 143. Interferences by various ions are examined. Zr, Ti and Mo interfere heavily. The method is applied for the determination of iron in Al-based and Cu-based alloys, using appropriate masking agents.     

Extraction-spectrophotometric determination of nickel as Ni-(PAR)2-(CTAB)2 complex in polymetallic sea-bed nodules and steels

A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 μg/ml with a molar absorptivity of 45 200 L·mol^?1·cm^?1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04–0.127 μg for 5–25 μg of nickel.     

CeCl3·7H2O: a highly efficient catalyst for the synthesis of 1-substituted-octahydro-[1,3,2]diazaphospholo[1,5-a]pyridine-1-oxide

An efficient and simple protocol is reported for the synthesis of a new class of 1-substituted-octahydro-[1,3,2]diazaphospholo[1,5-a]pyridine-1-oxides in good to excellent yield (88–95%) via Michaelis–Arbuzov rearrangement. Condensation of diamido phosphite with various halides at 60 °C using CeCl₃·7H₂O as a highly efficient catalyst afforded the products within a short period of reaction time. This procedure is mild, efficient, and non-toxic and stability of the catalyst is the merit of this process. Therefore, this protocol being environmentally benign and efficient, serves as an alternative procedure for the preparation of the title compounds.     

Iron-carbon nanohybrid particles as environmentally benign electrode for supercapacitor

Journal of Solid State Electrochemistry - In this work, we report the synthesis and electrode applications of iron-carbon nanohybrid particles prepared by carbonization of a nanocomposite of FeOOH...     

Existence of infinitely many solutions for a nonlocal elliptic PDE involving singularity

Positivity - In this article, we will prove the existence of infinitely many positive weak solutions to the following nonlocal elliptic PDE. $$\begin{aligned} (-\Delta )^s u&= \frac{\lambda...     

Design and Synthesis of 1,3,4-Thiadiazole Derivatives as Novel Anticancer and Antitubercular Agents

Russian Journal of General Chemistry - A series of novel 5-phenyl-substituted 1,3,4-thiadiazole-2-amines were designed, synthesized, and screened for their antitumor and antitubercular activities....     

Investigation on the energy and exergy efficiencies of a domestic refrigerator retrofitted with water-cooled condensers of shell-and-coil and brazed-plate heat exchangers

Journal of Thermal Analysis and Calorimetry - Domestic refrigerator is one of the major energy-consuming appliances, and the enhancement of its energy efficiency plays a vital role in implementing...     

Stokes flow past a porous sphere with an impermeable core

Stokes flow of a viscous, incompressible fluid past a porous sphere with an impermeable core using Darcy law for the flow in the porous region is discussed. The formulae for drag and torque are found by deriving the corresponding Faxen's laws. It is found that torque is always less than that on a solid sphere and it does not depend on the radius of the impermeable core. Some illustrative examples are discussed.