Impulse diagrams

The two conditions that vary the most in a turbine are the inlet pressure and temperature. Two diagrams are needed to show their characteristics. Figure 3-12 is a performance map that shows the effect of turbine inlet temperature and pressure, while power is dependent on the efficiency of the unit, the flow rate, and the available energy (turbine inlet temperature). The effect of efficiency with speed is shown in Figure 3-13. Figure 3-13 also shows the difference between an impulse and a 50% reaction turbine. An impulse turbine is a zero-reaction turbine. 

Impulse diagram. For the impulse rotor, the reaction is zero, so the relative velocity of the gas is constant, or = W/. If the work factor is less than 2.0, the exit swirl is positive, which reduces the stage work. For this reason, an impulse diagram should be used only if the work factor is 2.0 or... 

Figure 9-6 shows a diagram of a single-stage impulse turbine. The statie pressure deereases in the nozzle with a eorresponding inerease in the absolute veloeity. The absolute veloeity is then redueed in the rotor, but the statie pressure and the relative veloeity remain eonstant. To get the maximum energy transfer, the blades must rotate at about one-half the veloeity of the gas jet veloeity. Two or more rows of moving blades are sometimes used in eonjunetion with one nozzle to obtain wheels with low blade tip speeds and stresses. In-between the moving rows of blades are guide vanes that redireet the gas from one row of moving blades to another as shown in Figure 9-7. This type of turbine is sometimes ealled a Curtis turbine.

Figure B-1. Pressure impulse diagrams for damage to brick houses. Line 1 Threshold for light damage. Line 2 Threshold or moderate damage partial collapse of roof some bearing wall failures. Line 3 Threshold for severe damage 50 to 75 percent of bearing wall destruction. P, side-on overpressure. /, side-on impulse (Baker et al. 1983).

Most of the criteria found in literature are extracted from Bowen et al. (1968). Diagrams of pressure versus duration are presented for various body positions in relation to the blast wave, from which the chance of survivability can be calculated. Those diagrams were combined in a pressure-impulse diagram, which is depicted in Figure C-1. The scaled overpressure P equals Plp, in which P is the actual pressure acting on the body, and po is the ambient pressure. The scaled impulse i equals ... 

Figure C-1. Pressure-impulse diagram for lung injury. P scaled overpressure. / scaled impulse. (Bowen et al. 1968).

Figure 49-8. Diagram of the relationships among the sarcolemma (plasma membrane), a T tubule, and two cisternae of the sarcoplasmic reticulum of skeletal muscle (not to scale). The T tubule extends inward from the sarcolemma. A wave of depolarization, initiated by a nerve impulse, is transmitted from the sarcolemma down the T tubule. It is then conveyed to the Ca release channel (ryanodine receptor), perhaps by interaction between it and the dihydropyridine receptor (slow Ca voltage channel), which are shown in close proximity. Release of Ca from the Ca release channel into the cytosol initiates contraction. Subsequently, Ca is pumped back into the cisternae of the sarcoplasmic reticulum by the Ca ATPase (Ca pump) and stored there, in part bound to calsequestrin.

The time variations of the effluent tracer concentration in response to step and pulse inputs and the frequency-response diagram all contain essentially the same information. In principle, any one can be mathematically transformed into the other two. However, since it is easier experimentally to effect a change in input tracer concentration that approximates a step change or an impulse function, and since the measurements associated with sinusoidal variations are much more time consuming and require special equipment, the latter are used much less often in simple reactor studies. Even in the first two cases, one can obtain good experimental results only if the average residence time in the system is relatively long. 

Figure 17. Impulse Versus Pressure Diagram for Constant Levels of Building Damage. (Reprinted with permission from ref. 15. Copyright 1983 Elsevier Science.)...

Figure 17. Composition diagram of expected specific impulse for ammonium perchlorate-aluminum-polyurethane (PU) propellant (polyester binder). Pc/Pe = 1000/14.7 p.s.i.a. 10KS-2500 motors...

A highly simplified diagram of the intestinal wall and some of the circuitry of the enteric nervous system (ENS). The ENS receives input from both the sympathetic and the parasympathetic systems and sends afferent impulses to sympathetic ganglia and to the central nervous system. Many transmitter or neuromodulator substances have been identified in the ENS see Table 6-1. ACh, acetylcholine AC, absorptive cell CM, circular muscle layer EC, enterochromaffin cell EN, excitatory neuron EPAN, extrinsic primary afferent neuron 5HT, serotonin IN, inhibitory neuron IPAN, intrinsic primary afferent neuron LM, longitudinal muscle layer MP, myenteric plexus NE, norepinephrine NP, neuropeptides SC, secretory cell SMP, submucosal plexus. 

Schematic diagram of a reentry circuit that might occur in small bifurcating branches of the Purkinje system where they enter the ventricular wall. A Normally, electrical excitation branches around the circuit, is transmitted to the ventricular branches, and becomes extinguished at the other end of the circuit due to collision of impulses. B An area of unidirectional block develops in one of the branches, preventing anterograde impulse transmission at the site of block, but the retrograde impulse may be propagated through the site of block if the impulse finds excitable tissue that is, the refractory period is shorter than the conduction time. This impulse then reexcites tissue it had previously passed through, and a reentry arrhythmia is established.

A schematic diagram, Figure 6, shows a typical underwater test configuration and oscilloscope record used to determine shock wave impulse. The pressure vs. time is displayed both at fast and slow scope speeds and the impulse vs. time at the faster scope speed. The impulse vs. time is electronically integrated from the pressure vs. time signal from the pressure gauge. 

Fig 6 This diagram shows an Underwater Test Configuration and the oscilloscope record used to determine shock wave impulse (positive of the record at right)... 

Schematic diagram of a typical motor neuron (a nerve cell conducting impulses to muscle cells).

Classically, the central nervous system has been envisioned as a series of hard-wired synaptic connections between neurons, not unlike millions of telephone wires within thousands upon thousands of cables (Fig. 1—4). This idea has been referred to as the anatomically addressed nervous system. The anatomically addressed brain is thus a complex wiring diagram, ferrying electrical impulses to wherever the wire is plugged in (i.e., at a synapse). There are an estimated 100 billion neurons, which make over 100 trillion synapses, in a single human brain. 

Gibson method. The mean velocity in a penstock leading from a reservoir can be determined by rapidly closing a valve at the lower end and recording a pressure-time diagram at a point just upstream from the valve. The principle that impulse equals change of momentum can be applied to the mass of liquid between the reservoir and the point of measurement. The impulse is given by the area under the recorded pressuretime curve, and from this the initial velocity can be determined [10]. 

The determination of the thrust of a rocket motor involves recording the time diagram of the force (tons, kp, or newtons) during combustion. The force is allowed to act on a support, with a pick-up element thrust cell interposed between them. The measurement is carried out by the aid of a strain gauge element (variation of resistance with pressure) or of a piezo-quartz element, and the results are recorded on an oscillograph connected in a compensation circuit. Modern measuring and computation techniques yield the total thrust time (impulse) immediately. 

Fig. 4.7.2. Schematic diagram of a Curie-point pyrolyzer (Fischer, Germany). Note the possible modifications of the wire tip (a, b, and c) for solid samples. Pyrolysis glass injector (/), ferromagnetic wire (2), carrier gas inlet (3), impulse cable from power generator (4), induction coil (5), aluminum box (6), adapter for GC injector (7), GC inlet (8), GC septum (9), GC oven (10)...

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