A numerical trajectory optimization study of two types of lifting-entry reentry vehicle has been presented at low suborbital speed of 4.113 km/s and -15 degree entry angle. These orbital speeds are typical of medium range ballistic missile with ballistic range of approximately 2000 km at optimum burnout angle of approximately 41 degree for maximum ballistic range. A lifting reentry greatly enha...

An advanced guidance law is developed for reentry phase of a reentry vehicle. It can achieve small miss distance and desired impact attitude angle, simultanceously. To meet this requirment a guidance law based on the fuzzy logic approach is developed. It is partitioned into three stages. This guidance law does not require linearization of missile engagement model. Line-of-sight and flight path ...

The intramural dynamics of ventricular fibrillation (VF) remain poorly understood. Recent investigations have suggested that stable intramural reentry may underlie the mechanisms of VF. We performed optical mapping studies of VF in isolated swine right ventricles (RVs) and left ventricles (LVs). Nine RV walls were cut obliquely in their distal edge exposing the transmural surface. Six LV wedge ...

To determine the role of pectinate muscle (PM) bundles in the formation of intra-atrial reentry, 10 isolated canine right atrial tissues were perfused with Tyrode's solution containing 1 to 2.5 micromol/L acetylcholine (ACh). The endocardium was mapped using 477 bipolar electrodes with 1.6-mm resolution. Reentry was induced by a premature stimulus (S2). Computer simulation studies were used to ...

REENTRY HAS BEEN FREQUENTLY proposed as a mechanism for a variety of cardiac arrhythmias. For certain types of arrhythmias, the role of reentry appears well established.1 10 While intra-atrial reentry has long been suspected as a mechanism of some form of atrial arrhythmias, the phenomena of interor intra-atrial reentry in man have rarely been documented.8 11 The inability to demonstrate intero...

avnrt, (atrioventricular nodal reentry tachycardia), atrial tachycardia and atrial flutter are 3 kinds of supraventricular tachycardia, which their mechanism are explained based on reentry. a 60-years-old man is presented with all of the above-mentioned arrhythmias, responsive to intravenous injection of adenosine. radiofrequency ablation of the slow pathway territories cured all of them. there...

THE QUESTION WHETHER tachyarrhythmias are caused by enhanced impulse formation (“focus”) or by reentrant excitation (“reentry”) has been the subject of debate for more than a century. In 1887 McWilliam (12) was the first to suggest that disturbances in impulse propagation could be responsible for fibrillation, and he clearly envisaged the possibility that myocardial fibers could be reexcited as...