Search

A new two-dimensional model is presented that allows describing the high speed electrochemical machining of steel in NaNO3 solutions. Unlike existing models, local ion concentrations are calculated and used to evaluate local diffusion coefficients and electrolyte conductivity. Secondly, the presence of a super-saturated, honey-like layer on the anode surface is accounted for by introducing a water depletion factor. This factor describes the suppression of the oxygen evolution as the vast increase in ion concentrations reduces the amount of free water molecules at the anode. It is demonstrated that this approach enables to reproduce experimental average efficiency curves over a broad range of electrolyte concentrations with just a limited set of adjustable parameters. [ABSTRACT FROM AUTHOR]

A letter is presented in response to the article "A randomized RSA study concentrating especially on continuous migration" by M. Molt and others, in a 2016 issue.

A versatile model for the simulation of transient multiion transport and reaction processes is applied to investigate current density distributions over a rotating disk electrode for linear voltammetric sweep experiments. The model accounts for ion transport by convection, diffusion, and migration, in combination with Butler-Volmer type electrode reactions. For several process conditions (reversible and irreversible reactions, excess or lack of supporting electrolyte), the current density distribution over the disk surface is examined and the transient current response is compared to results from the more commonly used one-dimensional axial approach. The impact of migrational effects on the nonuniform local process conditions over the disk surface is illustrated, and the resulting effect on the current peak height, width, and position is investigated. A mathematical correlation for the current peak height as a function of the reacting ion transference number is established.

The authors review the literature and their personal experience about the systematic exploration of defecation disorders by anorectal manometry and colpocystodefecography. They stress the importance of combining functional and morphological evaluation, in order to avoid inappropriate surgery. Concerning anorectal manometry, the determination of the smallest volume of rectal distention inducing a complete relaxation of the internal anal sphincter was found more useful than the maximal tolerable volume in the exploration of defecation disorders. Finally, the authors report the results of biofeedback conditioning prescribed in 30 patients (27 women, 3 men, mean age: 55 years) with defecation disorders (terminal constipation in 21, fecal incontinence in 9 patients). Several characteristics of anorectal manometry and of defecography were significantly improved after biofeedback conditioning.

The authors present a series of 30 unstable bladders treated only by perineal muscular reeducation by contact. The best results are obtained in the group presenting with pelvic floor hypotonia and USI (efficiency 71.5%), especially when the closure pressure is normal (100%). The urodynamic control and the ominious disappearance of the associated USI confirm a muscular role of the treatment rather than a psychogenic one, the stabilization of the bladder being achieved through the perineo-detrusor inhibitory reflex. Because of this specific and efficient treatment the attention is drawn to the pelvic muscular weakness in the genesis of detrusor instability which is then called "deficitory instability". The interest of a clinical classification of detrusor instability is discussed.

The authors present a series of 30 unstable bladders treated only by perineal muscular reeducation by contact. The best results are obtained in the group presenting with pelvic floor hypotonia and USI (urinary stress incontinence) (efficiency 71.5%), especially when the closure pressure is normal (100%). The urodynamic control and the ominous disappearance of the associated USI confirm a muscular role of the treatment rather than a psychogenic one, the stabilization of the bladder being achieved through the perineo-detrusor inhibitory reflex. Because of this specific and efficient treatment the attention is drawn to the pelvic muscular weakness in the genesis of detrusor instability which is then called "deficitory instability". The interest of a clinical classification of detrusor instability is discussed.