Peak impact pressure

These guns were developed to attain much higher impact velocities than those available with powder guns (Crozier and Hume, 1957 Curtis, 1962). Peak velocities in the 7-8 km/s range can be routinely attained, with peak shock pressures approaching 1 TPa in high impedance materials. 

We saw that the rarefaction traveling axially into the rear of the shock pulse in an explosive can attenuate the peak shock pressure, and thereby cause longer than ideal run distance or even cause detonation failure. Rarefactions traveling radially into the sides or edges of the impact shock wave can do the same. 

Since the value of Fg is not greater than 1, the exposure is within permissible limits. Also note that exposure to impulsive or impact noise should not exceed 140-dB peak sound-pressure level. 

Impulse or impact noise 140 peak sound pressure level... 

Shock Synthesis. When graphite is strongly compressed and heated by the shock produced by an explosive charge, some (up to 10%) diamond may form (26,27). These crystaUite diamonds are small (on the order of 1 llm) and appear as a black powder. The peak pressures and temperatures, which are maintained for a few microseconds, are estimated to be about 30 GPa (300 kbar) and 1000 K. It is beheved that the diamonds found in certain meteorites were produced by similar shock compression processes that occurred upon impact (5). 

The peak pressures attainable with explosive facilities can be greatly enhanced, and the initial peak pressure can be better sustained by using a plane-wave generator to accelerate a flyer plate, which then impacts a flat specimen as shown in Fig. 3.2. This technique will generate peak pressures up to a few hundred GPa. (McQueen and Marsh, 1960 McQueen et al., 1970). 

G.T. Gray III and P.S. Follansbee, Influence of Peak Pressure and Pulse Duration on the Substructure Development and Threshold Stress Measurements in Shock-loaded Copper, in Impact Loading and Dynamic Behavior of Materials (edited by C.Y. Chiem, H.-D. Kunze, and L.W. Meyer), Deutsche Gesellschaft fuer Metall-kunde, Germany, 1988, 541 pp. 

Typical normal-phase operations involved combinations of alcohols and hexane or heptane. In many cases, the addition of small amounts (< 0.1 %) of acid and/or base is necessary to improve peak efficiency and selectivity. Usually, the concentration of polar solvents such as alcohol determines the retention and selectivity (Fig. 2-18). Since flow rate has no impact on selectivity (see Fig. 2-11), the most productive flow rate was determined to be 2 mL miiT. Ethanol normally gives the best efficiency and resolution with reasonable back-pressures. It has been reported that halogenated solvents have also been used successfully on these stationary phases as well as acetonitrile, dioxane and methyl tert-butyl ether, or combinations of the these. The optimization parameters under three different mobile phase modes on glycopeptide CSPs are summarized in Table 2-7. 

A Finnigan MAT TSQ mass spectrometer was used to record the mass spectra of brinzolamide. The conditions were 0.3 mA current, 1100-volt acceleration voltage and 10 preamp sensitivity. The ionization voltage was 70 eV for El (electron impact) ionization mode. For Cl (chemical ionization) mode, a positive ionization voltage of 100 eV and a pressure of 0.3 torr of methane were used. The El and Cl spectra are shown in Figures 12 and 13, respectively. Peak assignments for the El and Cl spectra are listed in Table 6. Both the Cl and El spectra have an MH peak at m/z = 384. 

For tunable-diode-laser(TDL) studies where r(x) is much narrower than even a modestly pressure-broadened line, one might either attempt the former method characterized by Eq. (49) or perhaps simply ignore (cautiously) the impact of r(x). From the foregoing discussion, however, it should be obvious that the considerations and potential problems involved in going beyond removal of the effect of r(x) are in no way trivial. Nevertheless, we have successfully deconvolved some data beyond the limit of the removal of r(x). In many instances we have only taken 0.012-cm-1 data for a 0.005-cm 1 Doppler spectrum to. 0.004 cm -1 and have encountered no serious problems. (Quantities refer to FWHM of the peaks.) In other instances, we have deconvolved 0.002-cm-1 TDL spectra of C2H6 at 12 jim to 0.0009 cm-1, which is roughly one-half the Doppler limit. An example is shown in Chapter 7. 

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