Electrodeposition of lead-tin alloy from fluoborate solution-a voltammetric study

Lead-tin alloy deposition is done commercially from fluoborate bath. Though the practical aspects of addition agents for producing quality deposits are widely reported, the basic aspects on influence of these addition agents on alloy deposition are important. The techniques of cyclic and linear stripping voltammetry on a copper electrode in a fluoborate solution, with and without addition agents, have been employed to throw light on the basic aspects, with the aim of understanding, optimizing and controlling lead-tin alloy depositio

Production of gallium - preliminary experiences of a pilot plant operation

The Madras Aluminium Company, Mettur Dam haxi put up a pilot pbnt for the extraction of gaHium from sodium aluminate liquors besed on amalgam rnecellurgy,the procea, end the engineaing chign king auppbd by Centrsl Ebctrochemiil Research Institurn, Karaikudi. The performance of the pikt plent and the raults obtaimd in the tim few mMhs of operetian are described in thii paper

Gap width modification on fully screen-printed coplanar Zn|MnO2 batteries

Fully printed primary zinc-manganese dioxide (Zn|MnO2) batteries in coplanar configuration were fabricated by sequential screen printing. While electrode dimensions and transferred active masses were kept at constant levels, electrode separating gaps were incrementally enlarged from 1 mm to 5 mm. Calendering of solely zinc anodes increased interparticle contact of active material within the electrodes while the porosity of manganese dioxide based electrodes was maintained by non-calendering. Chronopotentiometry revealed areal capacities for coplanar batteries up to 2.8 mAh cm−2. Galvanostatic electrochemical impedance spectroscopy measurements and short circuit measurements were used to comprehensively characterise the effect of gap width extension on bulk electrolyte resistance and charge transfer resistance values. Linear relationships between nominal gap widths, short circuit currents and internal resistances were evidenced, but showed only minor impact on actual discharge capacities. The findings contradict previous assumptions to minimise gap widths of printed coplanar batteries to a sub-millimetre range in order to retain useful discharge capacities. The results presented in this study may facilitate process transfer of printed batteries to an industrial environment

Elevated PAF1-RAD52 Axis Confers Chemoresistance to Human Cancers

Cisplatin- and gemcitabine-based chemotherapeutics represent a mainstay of cancer therapy for most solid tumors; however, resistance limits their curative potential. Here, we identify RNA polymerase II-associated factor 1 (PAF1) as a common driver of cisplatin and gemcitabine resistance in human cancers (ovarian, lung, and pancreas). Mechanistically, cisplatin- and gemcitabine-resistant cells show enhanced DNA repair, which is inhibited by PAF1 silencing. We demonstrate an increased interaction of PAF1 with RAD52 in resistant cells. Targeting the PAF1 and RAD52 axis combined with cisplatin or gemcitabine strongly diminishes the survival potential of resistant cells. Overall, this study shows clinical evidence that the expression of PAF1 contributes to chemotherapy resistance and worse clinical outcome for lethal cancers

Monovalent copper in aqueous acidic-chloride electrolyte: A cyclic voltammetric study

The cyclic voltammetric technique has been employed on a copper electrode in a solution of copper- I/acidicchloride to investigate the basic aspects of cuprous ion reduction with the particular aim of understanding the role of and arriving at the optimum composition of the bath constituents. It allowed the study of the effects of sodium chloride and hydrochloric acid concentration on copper- Vacidic-chlroide system particularly for arriving at the optimum electrolyte compositio

Some contributions to the electrochemistry of gallium-cyclic voltammetric studies in alkali and alkaline gallate solutions

Electrochemistry of gallium, particularly in alkaline medium is important from the view point of its recovery from Bayer’s liquor-one of the chief sources for gallium. Very few studies are reported in literature coercing the basic aspects of gallium electrochemistry in alkaline medium. Among other reasons, the difficulty of obtaining reliable and reproducible experimental data using gallium working electrodes contributed to a considerable extent to the existence of meagre basic work in this field. In the present work an attempt is made to critical review the available information on the electrochemical behavior of gallium in alkaline medium with a view to highlight the status of the field as it exists and present the various approaches hitherto attempted. This is present in the Chapter-1. Following the presentation of the existing literature, the scope for studies involving a new configuration of the gallium working electrode in the form of Gallium film electrode envisaged in this work has been traced in the same chapter. The introductory Chapter-1 also includes a brief description of the cyclic voltammetry technique and its application in electrode kinetic studies. Methods for the standardization of the gallium film preparation on a suitable substrate material, its evaluation and application in various electrochemical experiments involving both alkali and alkaline gallate media constitute one part of the work. In the other part of the work electrochemical behavior of alkaline gallate at a Hanging Mercury Drop Electrode (HMDE) has been studied and reported. In the subsequent chapters that follow work relating to these two parts has been elaborated. The major experimental technique employed for the polarization studies is cyclic voltammetry – a technique of great importance that is providing to be useful currently in understanding the kinetics and mechanism of the electrode reactions. A wider application of this important technique to the studies involving Gallium has not been done so far. Chapter-II deals with the various experimental aspects of the work such as the details of electrochemical cells employed, the preparation of the solutions used, description of the experimental set up and procedure procedures employed. In Chapter-III experimental results on the optimization of conditions for the electrode position of the gallium film and its characterization to establish its identify through various electrochemical experiments have been described. Chapter-IV deals with the application of the above gallium film in the cyclic voltammetric studies in various concentrations of pure sodium hydroxide and in gallate solutions containing sodium hydroxide. The sweep rate dependence and the alkali concentration dependence of the various features of the cyclic voltammograms – many of which have not been reported earlier and are noticed for the first time in this work are recorded and analysed. Based on these observations an attempt is made to understand the various stages of the anodic oxidation of gallium and the cathodic reduction of gallium under cyclic voltammetric conditions and presented. In the next Chapter-V, the application of the cyclic voltammetric technique has been extended to the studies on HMDE in alkaline gallate solutions that constitute the second part of the work. The objective of this study is to highlight the role of sodium-amalgam in the recovery of gallium metal. The observations obtained from these studies, apart from helping in elucidating the role of sodium in gallium recovery, have resulted in the emergence of a new approach that led to an improved anodic stripping voltammetric technique which holds promise as a simple and sensitive method for analysis at trace levels of various amalgamable metals including gallium. The details of the above observations are presented and discusse

Cyclic voltammetric studies on reduction of silver from synthetic colour bleach fix solutions

Cyclic voltammetric studies were carried out to understand the electrochemical aspects of the reduction of silver ion from synthetic colour bleach fix solutions (SCBF solution). The results obtained have helped in throwing light on the mechanism of the above process and for optimising the various parameters with a view to increase the current efficiency. Based on the cyclic voltammetric informations, controlled potential electrolysis experiments were also carried out to find out the silver deposition efficienc

Anodic current peaks during cathodic sweep in cyclic voltammetric studies on gallium film electrode in alkaline solutions

A gallium film electrode (prepared ‘in situ’) yielded reliable and reproducible polarisation data, indicating its potentialities in kinetic studies. The cyclic voltammogram indicates the appearance of anodic peak during the cathodic sweep and has been noted in this work. The potential regime over which the anodic peak currents appeared, the effect of alkali concentration sweep rate and the reversal of voltage excursion at different potential regimes on the anodic peak current have been investigated. The resultant experimental observations indicate the formation of a lower valent intermediate to be responsible for yielding this anodic peak curren

Effects of certain impuritites on alkaline gallate reduction-a stripping voltammetry study

Gallium is mainly electrowon from sodium aluminate solution (Bayer liquor) of aluminium industries by electrolytic method. The effective recovery of gallium is inhibited by the presence of metallic and organic impurities. Investigations on the effect of certain metallic impurities, employing linear sweep stripping voltammetry technique on rotating glassy carbon disc electrode revealed the inhibitive effect of these ions on gallium recovery process in alkaline mediu