Point of maximum impulse

The physical examination was remarkable for jugular venous distention, a holosystolic murmur, a point of maximum impulse displaced to the left, and pedal edema. 

On physical examination she was normoten-sive. The heart rate was eighty-six and the rhythm at the time was regular. No murmur was evident. The point of maximum impulse was shifted to the left. There was jugular venous distension and mild ankle edema. She had scars of the neck, anterior chest —midline and left pectoral area, relative to previous surgeries. The protrusion of a mechanical device was evident in her abdominal wall. 

Those entrusted with the development of propellant systems frequently have attempted to gain insight from new analyses, only to find the fundamental conceptual results of the analyses obscured in non-understandable detail. Correspondingly, many books which have appeared report and analyze the performance of chemical propellants (9 through 13). Yet rarely is an attempt made to explain why the performance results of the analyses are oriented as they are. This monograph is an attempt to state clearly the important concepts of propellant evaluation and to answer the important question of why Why is one propellant better than another, why does the point of maximum specific impulse shift towards stoichiometric mixture ratio as the chamber pressure is increased, why doesn t one obtain equilibrium chamber product concentrations with certain monopropellants, etc ... 

The point of intersection of I, R M is known as the triple point, TP. The resulting existence of the above three waves, causes a density discontinuity. The surface of this discontinuity, known as slipstream, S, represents a stream line for the flow relative to the intersection. Between this and the reflecting surface is the region of high pressure, known as Mach region here the pressure is approx twice that behind the incident wave. The top of this pressure region, the triple point, travels away from the reflected surface. As pressure and impulse appear to have their maximum values just above and below the triple point, respectively, the region of maximum blast effect is approximately that of the triple point... 

The present consideration is limited to the effect of mixture ratio upon performance as measured simply by specific impulse. Since maximum enthalpy of reaction and minimum product molecular weight will not occur at the same mixture ratio one would predict, priori that the optimum mixture ratio should fall between the mixture ratio of maximum enthalpy of reaction and the mixture ratio of lowest product density. The maximum enthalpy of reaction occurs at the stoichiometric mixture ratio, that ratio at which there is theoretically just sufficient oxidizer to completely oxidize the fuel elements. Any excess fuel or oxidizer essentially acts as a diluent. The maximum temperature thus should fall at the stoichiometric point. 

Figure 8 shows the effect of mixture ratio on performance at a chamber pressure of about 1.2 MPa. It was shown the maximum vacuum specific impulse at near the mixture ratio of 1.60. From Figure 8, it may be seen that the mixture ratios of peak specific impulse coincides with those corresponding to the designed Rupe number of 0.5. This is perhaps due to the non-reactive effects of 5ie core flow with the film coolant as shown in the film cooled thrust engines.( ) The mixing factor M at the peak vacuum specific impulse was 0.85, which was the small value compared to the designed point of 1.0. The vacuum specific impulse I py decreased... 

The profile of the impulse as a function of the pressure inside the PDF tube (more specifically at the closed-end) provides a useful check on the potential for impulse maximization. As shown in Fig. 14.3 for a uniform mixture ( = 0.5), the pressure-impulse combination evolves from the lower-right corner towards the higher-left corner, at which time the maximum impulse is achieved. The point then enters a tightening spiral until steady state is achieved. If the pressure at the top-left corner is sufficiently low, one could initiate injection sufficiently early to avoid the start of the spiral, which results in lowering of the impulse and cycling frequency. According to Fig. 14.3, optimization can be achieved if the reservoir pressure is higher than 1 atm. 

In data-point units, the original infrared peaks were about 34 units wide (full width at half maximum). This corresponds to an actual width of approximately 0.024 cm-1. The impulse response function was about 25 units wide. After inverse filtering and restoration of the Fourier spectrum, the resolved peaks were 11 and 14 units wide, respectively. This is close to the Doppler width of these lines. 

However, there is a severe disadvantage with one-dimensional models they do not take into account the dilution due to the transversal dispersion. Consequently a mass M, that is not susceptible to any chemical reaction, occurs blurred at a point x downstream from xo (the location of M input) due to longitudinal dispersion. The dispersion leads to a smaller maximum concentration, however, and the mass integral equals the mass added at xo. Thus, the impulse of mass remains constant along any simulated one-dimensional distance. 

To obtain as complete a picture as possible of the kinetics, it is important to obtain a maximum time resolution. Many biological reactions occur in a very short time (in fact, down to picoseconds in vision and photosynthesis) so that slower, more traditional techniques such as stopped-flow often lack adequate time resolution. Under fortunate circumstances where the system studied is photosensitive, or where the free-energy change between reactants and products is sufficiently small, then the concentrated energy impulse from a laser is a marvelous tool that can provide a wealth of information concerning the system. The intent of the review is not to offer an exhaustive review of the literature, which would be an overwhelming task. Rather we hope to delineate areas where lasers have played an important role, to discuss the importance of these investigations, and to point to areas where their potential is still untapped. 

An analysis of the calculated pressure-time histories pj[t) for a cylinder (Fig. 4a the gauges are placed at points 1. .. 5 with 0 = 0, 45, 90, 135, and 180 deg respectively) shows that under the impact of SW a hot gas layer decreases the maximum pressure in the front part of the body and increases it in the rear part, as compared with the same process without a hot layer. This results in a decrease in the horizontal projection of the total force (when f - 1 + 1.5) and the impulse (Fig. 4b) ... 

Most of the experimental data have been obtained with point-plane and rod-plane geometries and an impulse voltage rectangular voltage or "lightning surge" (1-ys rise time, one-half of the maximum voltage at... 

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