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

Treatment of renal transplant recipients with low bone mineral density: A randomized prospective trial of alendronate, alfacalcidol, and alendronate combined with alfacalcidol

We sought to compare the treatment modalities of alendronate, alfacalcidol, and alendronate combined with alfacalcidol in renal transplant recipients with low bone mineral density. Sixty-four kidney graft recipients (22 women, 42 men) were recruited to this study. Of these 64 patients, 9 served as the control group with T scores more than -1. The remaining 55 patients randomly assigned to treatment had T scores less than -1 and were assigned to 3 groups: group 1 received alfacalcidol (0.5 mu g/d); group 2, alendronate (10 mg/d); and group 3, alendronate (10 mg/d) + alfacalcidol (0.5 mu g/d per os). Twenty-five patients were allocated to alfacalcidol, 13 patients to alendronate, and 17 patients to alendronate + alfacalcidol treatment. Bone mineral densities of the lumbar spine and femoral neck were measured before and 12 months after treatment. The groups were compared for risk factors of osteoporosis, biochemistry, and bone mineral density. Kruskal-Wallis, one-way ANOVA, and Student t tests were used. With the alendronate + alfacalcidol group, bone mineral density at the lumbar spine significantly increased by 7.9% (P = .006) with a significant improvement in T score (P = .003). Bone mineral density at the femoral neck significantly increased by 8% in the alendronate + alfacalcidol group (P = .01) with a significant improvement in T score (P = .02). The use of a combination of alendronate and alfacalcidol seemed to be safe and more effective than the separate use of the 2 agents to improve bone mass in renal transplant recipients