Transient pressure changes

For such a process the pressure p of the surroundings remains constant and is equal to that of the system in its initial and final states. (If there are transient pressure changes within the system, they do not cause changes in the surroundings.) One may then write... 

The transient term can be neglected in most cases, but any sudden change in the energy will result in a pressure change. This can be responsible for puffing effects seen in compartment fires, especially when the burning is oscillatory. 

Relaxation methods can be classified as either transient or stationary (Bernasconi, 1986). The former include pressure and temperature jump (p-jump and t-jump, respectively), and electric field pulse. With these methods, the equilibrium is perturbed and the relaxation time is monitored using some physical measurement such as conductivity. Examples of stationary relaxation methods are ultrasonic and certain electric field methods. Here, the reaction system is perturbed using a sound wave, which creates temperature and pressure changes or an oscillating electric field. Chemical relaxation can then be determined by analyzing absorbed energy (acous-... 

A comparison is shown in Fig. 12.9 of the transient pressure difference between the two sides of the membrane after introducing a feed composition change at one side [30]. The good agreement between the predicted and measured... 

Fig. 3 Spotting tools for non-contact printing a Bubble ink-jet A heating coil locally heats the loaded sample, resulting in a changed viscosity and expansion of fluids. The generated droplet can be easily expelled from delivery nozzles, b Microsolenoid A microsolenoid valve, fitted with the ink-jet nozzle is actuated by an electric pulse transiently opening the channel and dispenses a defined volume of the pressurized sample, c Piezo ink-jet A piezoelectric transducer that is fitted around a flexible capillary confers the piezoelectric effect based on deformation of a ceramic crystal by an electric pulse. An electric pulse to the transducer generates a transient pressure wave inside the capillary, resulting in expulsion of a small volume of sample...

In vivo, intravenous administration of ET-1 to conscious [20], anaesthetized [21] or pithed [22] rats produces a biphasic blood pressure response a small, transient depressor response followed by a prolonged pressor response. The systemic blood pressure changes induced by ET-1 are reflected in changes in regional haemodynamics, although the dilator response is not seen in all vascular beds [23-25], Big ET-1, when administered intravenously, is almost as potent as ET-1 in producing a pressor response which suggests effective in vivo conversion to ET-1 [22]. The haemodynamic effects of ET-1 have also been studied in man and pressor responses are seen after intravenous or intra-arterial administration [26-28]. 

Transient cerebral ischemic attacks, unrelated to blood pressure changes, occurred with isosorbide dinitrate and glyceryl trinitrate ointment in a patient with previous cerebrovascular disease, and resolved on withdrawal... 

Upon recording the pressure after a]) >lying a pressure pulse across the sample, the so called lag time" r/ can be extracted [10]. Thereby, r corresponds to the intercept of the extrapolated stationary pressure change [dp/dl]., with the time axis [11]. rj is relatc d to the transient permeability P, ia r/ = d l( iPf).. s a result of the small sam )le thickness the lag time was very short and could not be (h tenniiK d with sulficic iit accuracy. 

Headache, nausea, restlessness, nervousness, trembling, dizziness, throat dryness, throat irritation, pharyngitis, blood pressure changes, hypertension heartburn, transient wheezing Insomnia, weakness, unusual/bad taste or taste/smell changes with inhalation... 

In a double shock wave with chemical reactions, unsteady behavior can lead to a p-v space path that is not necessarily well described by Rayleigh lines. However, we assume here that for a given period of time the p-v space path can be transiently approximated by a set of Rayleigh lines. This description is valid when the timescale of the pressure change at point B in Figure 2 is less than the time required for a material element to progress from the initial state to the final shocked state. A more quantitative version of this statement is formulated in the remainder of this section. 

The kinetics of the adsorption process taking place at the surface of a growing drop or bubble is important for the interpretation of data from drop volume or maximum bubble pressure experiments. The same problem has to be solved in any other experiment based on growing drops or bubbles, such as bubble and drop pressure measurements with continuous, harmonic or transient area changes (for example Passerone et al. 1991, Liggieri et al. 1991, Horozov et al. 1993, Miller at al. 1993, MacLeod Radke 1993, Ravera et al. 1993, Nagarajan Wasan 1993). 

Strictly speaking, beyond the inflexion point conditions are again transient, because the increasing pressure continuously reduces the flux from the sample. However, since the pressure change is very much smaller than the pressure drop across the sample, this perturbation is usually negligible, and after the inflexion point the curve of pressure against time is sensibly a straight line. 

To produce transients, a steady electrical current is introduced across the porous frit, using a second pair of electrodes. Below a threshold current value, the trans-frit potential and hydrostatic pressure change monotonically until they attain stationary values. In this regime, the frit acts as a slightly nonlinear electrical resistor, whose resistance depends on the partially distorted internal mobile ion concentration profile. Electro-osmotic flow due to the presence of fixed charges on the frit occurs... 

Internal or transient water pressure Changes to internal water pressure will change stresses acting on the pipe... 

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