Analysis of peak-holding optimalizing control

The peak-holding optimalizing control is analyzed under the assumption of first-order input linear group and output linear group. Design charts are constructed for determining the required input drive speed and the consequent hunting loss with specified time constants of the input and output linear groups, the hunting period, and the critical indicated difference for input drive reversal

A Procedure for Predicting Fuel Specific Impulse of Supersonic Combustion Ramjet Engines

This report presents a procedure in order to portray the effect of design choices on SCRAMJET dynamic performance in the context of real gas effects. Procedure is based on one-dimensional fluid flow analysis. The less quantifiable aspects of boundary layer transition, mixing, and non-uniform nozzle flow are included in approximate parametric fashion by allowing for parallel flow paths through the engine and nozzle, with possibility of thermal energy exchange between various flow streams. The effect of finite recombination rates in the nozzle is included by allowing for freezing of the chemical composition at any specified static pressure in the nozzle. Exploratory results from the digital implementation of this procedure in FORTRAN language are also included

Intracranial calcification and tumoural calcinosis during vitamin D therapy

Extraskeletal calcifications are frequently observed in patients with chronic renal failure. However, clinically, they usually remain silent. In this report, we describe two patients with massive extraskeletal calcifications that caused significant morbidity. The first patient had tumoural calcification located on the shoulder and the second patient had severe neurological symptoms caused by intracranial calcifications. High calcium phosphorus product and severe secondary hyperparathyroidism were present in both patients. Furthermore, they both received inappropriately high doses of active vitamin D, even though they failed to respond to this therapy. We suggest to monitor closely the calcium, phosphorus and parathyroid hormone levels during calcitriol therapy and to perform parathyroidectomy, without delay, in patients who were resistant to calcitriol