Showing papers on "Overpressure published in 1982"

Predicting abnormally pressured sedimentary rocks

Abstract: Modern seismic processing techniques developed in recent years have provided the explorationist with more meaningful data than would have been predicted even by optimists. Correct migration of seismic data, relative amplitude preservation of reflections, and seismic trace inversion represent the necessary efforts to ensure that the best possible picture of in situ physical properties of the subsurface section is revealed. Moreover, compacted and over-pressured zones can be predicted from surface data prior to drilling a well through them. The basic tool for predicting overpressured zones from the surface is still the velocity analysis derived from good reflection data with few erratic multiples. The extraction of regional normal compaction trends from the seismic velocities allows one—where velocities deviate from the trend—to locate the top of overpressure. Moreover, the statistical behavior of the ratios of the sonic log vs pore pressure in existing boreholes enables one to convert the deviation from the trend of the seismic velocities into overpressure rates expected at the seismic reflection horizon. This paper presents a field case study showing how the knowledge of well site lithology together with the more detailed information extracted from inverted seismic data enables the prediction to match well conditions with high reliability.

Valve control for low temperature overpressure protection in a nuclear power plant

Abstract: A control system for overpressure protection of the reactor coolant boundary (14) in a nuclear power plant, comprising a pressure relief line (18a) having a power operated relief valve (24a) controlled by a circuit responsive to the condition of the reactor coolant and a control logic. The circuit includes a mode selector switch (80) having a NORMAL position (82) for establishing a full power overpressure relief valve setpoint (62) and a LTOP position (84) for establishing a low temperature overpressure relief setpoint (58). The control system logic opens the relief valve (24a) when (a) the mode switch is in the NORMAL position and the coolant pressure exceeds the full power setpoint (62), or (b) when the mode switch is in the LTOP position, the coolant temperature is less than a preselected value (52) and the coolant pressure exceeds the LTOP setpoint (58).

Blast Parameters from Cylindrical Charges Detonated on the Surface of the Ground

Abstract: : Tables and diagrams of scaled side-on blast parameters are available for time of shock front arrival, primary shock front overpressure, overpressure impulse and positive duration for cylindrical RDX explosives having length to diameter ratios of 1 and 5. Charges were placed in a vertical, a horizontal and a 60 degrees inclined position to the surface of the ground. Initiation point was at one end. Blast parameters were measured along 9 blast lines at scaled standoffs from 0.5 to 32 mkg to the minus 1/3 power.

A study of pressure waves and explosions induced by contact of hypergolic liquid propellants

Abstract: Careful and detailed falling droplet experiments were made (droplet: unsymmetrical dimethylhydrazine,pool: fuming nitric acid), to obtain information on the mechanisms of the generation of a sequence of pressure waves (observed reproducibly) and explosions (observed occasionally), which is useful for safe-handling practices. The change of the shape of the droplet at the instant of impact, caused by the oscillation,has a definite influence on the impact overpressure value and on the possibility of occurrence (as well as the strength) of explosion. When the droplet is elongated, the value of impact overpressure (observed just after the contact of two liquids), is small and the possibility of an explosion is large, compared when the droplet shape is spherical or flattened. The experimental results showed that impact overpressure increases with V 2∼2.5 and D ∼2.5 (V: impact velocity, D: droplet diameter) and is considerably higher for large droplets with high impact velocities. The tendency of the impact overpressure to increase is explained satisfactorily based on simple acoustic source theory. It was shown that the occurrence of explosion and its strength are influenced considerably,not only by the droplet shape but also by the impact velocity, and, furthermore, explosion tends to become stronger when the time lag of occurrence is long. These experimental results are qualitatively consistent with the elucidation of the explosion phenomenon by Friedman et al, in which the role of turbulence is emphasized. In the present report, the influence of the thickness of the vapor layer formed between two liquids on the occurrence of the explosion is proposed, based on newly obtained experimental data.

Apparatus for indicating fluid flow

Abstract: A flow indicator has a pivoting flap fitted in ducting of a hydraulic installation which transports contaminated liquids. To permit the purge of a reservoir, the flap has an opening for air returning through the ducting. The opening prevents overpressure or vacuum in a circuit. The invention applies specifically to purge and vent circuits for nuclear power installations.

Sonic boom measurement test plan for Space Shuttle STS-3 reentry

Abstract: The lateral area from the reentry ground track affected by sonic boom overpressure levels is determined. Four data acquisition stations are deployed laterally to the STS-3 reentry flight track. These stations provide six intermediate band FM channels of sonic boom data, universal time synchronization, and voice annotation. All measurements are correlated with the vehicle reentry flight track information along with atmospheric and vehicle operation conditions.

Blast Wave Loading of a Two-Dimensional Circular Cylinder

Abstract: : A two-dimensional non-responding cylinder was exposed to decaying shock waves induced in the BRL 57.5 cm shock tube. Pressure-time records are shown for transducer locations spaced at 15 degree intervals around the cylinder for input side-on overpressure levels of 42.3, 75.9, and 112.2 kPa. Pertinent loading results are listed in tabular form.

Preliminary sonic boom correlation of predicted and measured levels for STS-1 entry

Abstract: A preliminary analysis correlating peaks from sonic boom pressure signatures recorded during the descent trajectory of the Orbiter Columbia, which landed in the dry lake bed at Edwards Air Force Base (EAFB), California, with measured wind tunnel signatures extrapolated from flight altitudes to the ground has been made for Mach numbers ranging from 13 to 6 The flight pressure signatures were recorded by microphones positioned at ground level near the groundtrack, whereas the wind tunnel signatures were measured during a test of a 00041-scale model Orbiter The agreement between overpressure estimates based on wind tunnel data using preliminary flight trajectory data and oscillograph traces from ground measurements appears reasonable at this time for the range of Mach numbers considered More detailed studies using final flight trajectory data and digitized ground measured data will be performed

Underpresssure pulsator for milking machines

Abstract: An underpressure pulsator for milking machines is described, which contains a valve pair which controls the alternate supply of underpressure and overpressure to a line which is connected to the pulsator. The pulsator contains adjustable vent valves which influence the frequency of the pressure change and/or the phase length of the change between underpressure and overpressure. The pulsator can be operated with compressed air or air at atmospheric pressure. The vent valves can be adjusted from outside.

Effect of Low Loading Density on Blast Propagation from Earth Covered Magazines

Abstract: : This report contains the results from a series of high explosive tests designed to determine the airblast parameters propagating to the front, side, and rear of an earth covered munition storage magazine with a low loading density. The tests were conducted with 1/30th-scale donor models and hemi- cylindrical pentolite charges of 0.227, 0.363, 1.088, 1.814, and 5.040 kg masses. These charge masses simulate full size munition storage magazines filled with 6130, 9800, 29370, 48980, and 136080 kg of explosive. The 48980 kg full size load was used as the baseline for comparing blast attenuation or enhancement from a full size load of 6130 kg. There was attenuation of both peak overpressure and impulse to the side and rear of the structure at the lower loading density. The impulse propagating to the front of the structure was enhanced while the peak overpressure showed no significant effect of the low loading density.

Sonic boom measurement test plan for Space Shuttle STS-4 reentry

Abstract: Formal documentation for measurement procedures and system specifications, and general information relating to the Space Shuttle STS-4 Sonic Boom Measurement Program are supplied. This test plan is designed to provide information, guidance, and assignment of responsibilities for the acquisition of sonic boom and atmospheric measurements, timing correlation, communications and other necessary supporting tasks. Specifically included are details such as mobile data acquisition station locations, measurement systems calibration levels, predicted sonic boom overpressure levels, overpressure level assignment for each data acquisition station, data recording times on and off, universal coordinated time, and measurement system descriptions.

Sonic boom measurement test plan for Space Shuttle STS-5 launch

Abstract: Sonic booms measurements are obtained at key locations within the focus region and the lateral attenuation rate during ascent is determined in order to assess the validity of existing capability to predict the extent of focus boom area, the number of booms within the various zones (focus and nonfocus regions), the overpressures, and focus factors. The sonic boom focus region, consists of a region on the ground (in the form of an inverted 'horseshoe' pattern) in which higher than nominal overpressures can occur.