Hydrogenation of butynediol to cis-butenediol catalyzed by pd-zn-caco3: reaction kinetics and modeling of a batch slurry reactor

An experimental study of the kinetics of hydrogenation of butynediol has been reported using Pd-Zn-Ca3 catalyst in a slurry reactor. The effects of catalyst loading, butynediol concentration, H2 partial pressure, butenediol (product concentration, temperature, and agitation speed on the rate of hydrogenation have been studied using a stirred pressure reactor). The initial rate data shwoed that the rate is proportional to the square root of H2 pressure, while increase in butynediol concentration inhibited the reaction. A Langmuir-Hinshelwood-type rate model has been proposed based on these data and the kinetic parameters evaluated. The values of the activation energy E and the heat of adsorption of butynediol (-ΔH) evaluated were 38.30 kJ/mol and -9.87 kJ/mol, respectively. Batch reactor models were derived based on the rate expression obtained from the initial rate data for variable pressure as well as constant pressure conditions. The prediction of the model were compared with experimental data obtained over a wide range of conditions. The predictions of the model were compared with experimental data obtained over a wide range of conditions. The results agreed well within 5-7% error. Use of the pressure vs. time data for evaluation of kinetic and mass transfer parameters is also demonstrated

Anatomy of the Hamstrings

This chapter will provide the anatomical foundation for the content to come in later portions of this book. It will begin with an overview of the proximal insertion sites of the muscles that comprise the hamstring group. The proximal tendons and musculotendinous junctions (MTJs) of semimembranosus, semitendinosus and the long and short heads of biceps femoris long head will then be described, highlighting the differences in structure between each of the muscles. The distinct architectural characteristics of each muscle belly (e.g. size, fascicle orientation within and between muscles) will be outlined, followed by the structure of the distal tendons and MTJs. Finally, a summary is provided of the neurovascular supply of the hamstrings