Design and Calibration of a Large Aspect Angle Total Head Pressure Gage

1972 ◽  
Author(s):  
C. H. Hoover
Keyword(s):  
Pressure Gage ◽  
Aspect Angle ◽  
Total Head ◽  
Head Pressure

GAS DYNAMIC TREATMENT OF EXOTHERMIC AND ENDOTHERMIC DISCONTINUITIES

1948 ◽  
Vol 26a (1) ◽  
pp. 1-21 ◽  
Author(s):  
D. G. Samaras
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Static Pressure ◽  
Density Ratio ◽  
Area Ratio ◽  
Compression Shock ◽  
Normal Velocity ◽  
Gas Dynamic ◽  
Total Head ◽  
Head Pressure

Endothermic and exothermic processes in gas dynamic flows taking place in a very narrow zone may be considered as discontinuities. The variation of the static and total head density ratio, pressure ratio, and temperature ratio as well as the angle of deviation, area ratio, and exit normal Mach number have been found as functions of the entry normal Mach number and of heat addition. In addition to these, some other useful quantities such as the area ratio parameter, the difference of the square of velocities, and the normal velocity product have been evaluated. It was found that, in a discontinuity, heat can be added until the exit normal Mach number reaches unity (choking). Depending on the entry normal Mach number, only a limited amount of heat can be added at the discontinuity. An exothermic discontinuity behaves as an expansion when the entry normal Mach number is subsonic, and it is accompanied by a drop in static pressure, density, and total head pressure. An exothermic discontinuity behaves as a compression shock wave when the entry normal Mach number is supersonic, and it is accompanied by an increase in static pressure and density and a decrease in total head pressure. An endothermic discontinuity behaves always as a compression shock wave, and it is accompanied by an increase in static density, pressure, and total head pressure. It is hoped that the results and conclusions found may be useful in a better understanding of many nearly discontinuous phenomena such as flame fronts, condensation and evaporation fronts, and other similar problems.

THE PROBLEM OF HEAT ADDITION IN DUCTS

1946 ◽  
Vol 24f (4) ◽  
pp. 272-286 ◽  
Author(s):  
D. G. Samaras
Keyword(s):  
Mach Number ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Frictional Coefficient ◽  
Extreme Value ◽  
Heat Addition ◽  
Total Head ◽  
Head Pressure ◽  
Temperature And Pressure ◽  
Head Temperature

The one-dimensional problem of heat addition in a duct with friction losses is examined.The variation of the total head temperature and pressure ratio, as well as the static ones, have been obtained as functions of the Mach number and the frictional coefficient. It is shown that an extreme value of the total head temperature and pressure ratio is obtained when the Mach number equals unity. An extreme value of the static temperature is obtained at Mach numbers smaller or larger than unity, depending on the form of the duct.It is concluded that when the total head pressure losses are to be kept low, a diverging duct must be used. The frictional losses have a convergence effect on the flow. When the friction losses are disregarded, no total head pressure loss will result if the area variation of the duct is such as to ensure a constant Mach number.The results and conclusions found may be useful in the design of combustion chambers for gas turbines, propulsive ducts, and rockets.

Effect of Display Line Rate and Antialiasing on the Recognition of Aircraft Aspect Angle

2007 ◽  
Author(s):  
Marc D. Winterbottom ◽  
George A. Geri ◽  
Byron J. Pierce
Keyword(s):  
Aspect Angle

Some Special Aspects of Hypersonic Flow Fields

1959 ◽  
Vol 63 (585) ◽  
pp. 508-512 ◽  
Author(s):  
K. W. Mangler
Keyword(s):  
Hypersonic Flow ◽  
High Speed ◽  
Flow Fields ◽  
The Body ◽  
Lower Velocity ◽  
Bow Wave ◽  
Total Head ◽  
Bow Shocks ◽  
Lower Entropy ◽  
Subsonic Region

When a body moves through air at very high speed at such a height that the air can be considered as a continuum, the distinction between sharp and blunt noses with their attached or detached bow shocks loses its significance, since, in practical cases, the bow wave is always detached and fairly strong. In practice, all bodies behave as blunt shapes with a smaller or larger subsonic region near the nose where the entropy and the corresponding loss of total head change from streamline to streamline due to the curvature of the bow shock. These entropy gradients determine the behaviour of the hypersonic flow fields to a large extent. Even in regions where viscosity effects are small they give rise to gradients of the velocity and shear layers with a lower velocity and a higher entropy near the surface than would occur in their absence. Thus one can expect to gain some relief in the heating problems arising on the surface of the body. On the other hand, one would lose farther downstream on long slender shapes as more and more air of lower entropy is entrained into the boundary layer so that the heat transfer to the surface goes up again. Both these flow regions will be discussed here for the simple case of a body of axial symmetry at zero incidence. Finally, some remarks on the flow field past a lifting body will be made. Recently, a great deal of information on these subjects has appeared in a number of reviewing papers so that little can be added. The numerical results on the subsonic flow regions in Section 2 have not been published before.

scholarly journals Pattern of Emergent Head Computed Tomography Findings in a Tertiary Care Hospital during off Working Hours: Retrospective Analysis

2019 ◽  
Vol 10 (02) ◽  
pp. 207-211
Author(s):  
Rajneesh K. Patel ◽  
Amit Kumar Choubey ◽  
Brijesh K. Soni ◽  
Rajeev Sivasankar ◽  
Vikash Chauhan
Keyword(s):  
Computed Tomography ◽  
Health Care ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Working Hours ◽  
Care Hospital ◽  
Head Ct ◽  
Total Head ◽  
Ct Head ◽  
Head Computed Tomography

ABSTRACT Introduction: Emergency head computed tomography (CT) is rising exponentially during off working hours due to evidence-based medicine, patient’s expectation and desires, easy availability and apprehension of medico-legal cases, thereby raising health-care cost. There is huge gap in demand and supply of radiologist, especially during off working hours. There is need to know the pattern of emergency head findings. Materials and Methods: A retrospective analysis of all emergent noncontrast CT head during off working hours in the Department of Radiodiagnosis of a Tertiary Care Hospital, Mumbai, India, which were performed from June 2017 to May 2018. CT findings of 308 patients were analyzed. Results: About 63.6% of total head CT showed no significant abnormality. The most common abnormality was intracranial hemorrhage which was just 9.1% followed by acute infarct which was 6.2%. Extradural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage was only 1% each of total head CT findings. No significant abnormality was detected in 74.65%, 70.21%, 89.13%, 31.37%, 100%, and 69.09% in cases of head injury, seizure, giddiness/dizziness/syncope, cerebrovascular accident, transient ischemic attack, and altered sensorium, respectively. Conclusion: Pattern analysis of emergent head CT reveals that most of the emergent CT head shows no significant abnormality. There is a need for stringent guidelines for emergent head CT, training of emergency physician as well as CT technician for common findings to bridge the radiologist demand-supply gap for providing effective health care in peripheral hospitals.

scholarly journals Iterative LP water system optimal operation including headloss, leakage, total head and source cost

2013 ◽  
Vol 15 (4) ◽  
pp. 1203-1223 ◽  
Author(s):  
Eyal Price ◽  
Avi Ostfeld
Keyword(s):  
Energy Consumption ◽  
Water System ◽  
Pump Energy ◽  
Optimal Operation ◽  
Water Levels ◽  
Water Leakage ◽  
Pump Operation ◽  
Total Head ◽  
System Optimal ◽  
Water Tanks

Linear water balance optimal operation models are common with relative short solution times but suffer from a lack of certainty whether the given solution is at all hydraulically feasible. Introducing hydraulic headloss, water leakage and changing pump energy consumption, effect the resulting system optimal operation but also create a non-linear problem due to the convex relation between flow, headloss, water leakage and total head. This study utilizes a methodology published by the authors for linearization of convex or concave equations. An iterative linear programming (LP) minimal cost optimal operation supply model is solved including the Hazen–Williams headloss equation, pressure related water leakage equation, changing pump energy consumption and source cost. The model is demonstrated using an example application. ‘Greater than’ or ‘less than’ water head constraints at nodes may force the system to maintain certain water levels in water tanks reducing the available operating volume forcing pumping stations to operate in peak tariff periods as less storage is available in low tariff periods. Operationally, reducing water leakage may be achieved by reducing water heads along the system by means of shifting pump operation periods and maintaining low water levels in water tanks. Source costs may serve as penalties or rewards discouraging or encouraging the use of certain water sources.

Head-Wear Measurements by Autoradiography of the Worn Magnetic Tapes

1986 ◽  
Vol 108 (1) ◽  
pp. 22-28 ◽  
Author(s):  
B. Bhushan ◽  
G. W. Nelson ◽  
M. E. Wacks
Keyword(s):  
Magnetic Tape ◽  
Wear Debris ◽  
Zinc Ferrite ◽  
Tape Drive ◽  
Average Amount ◽  
Nickel Zinc ◽  
Total Head ◽  
Drive Component

The transfer of wear debris of a nickel-zinc ferrite head to a magnetic tape was measured by autoradiography of the tape after it was worn against the irradiated ferrite head. Ferrite deposits on the tape were observed only after 5000 passes. Dots or specks on the autoradiograph of the tapes of about 200 micrometers in diameter, caused by particles of ferrite about 1 μm in diameter and mass of about 10−11 g, were measured. The average amount of ferrite deposited on the tape after 20,000 passes was about 0.6 nanogram per square centimeter; some areas showed uniform deposits of ferrite concentration of 10–20 ng/cm2. Based on our estimates of total head wear, only a small fraction (about 0.6 percent) of the total ferrite wear debris was transferred to the tape, about 0.2 percent was transferred to the tape-drive component surfaces, and the rest, we conclude, was airborne.

Total-Head (Brain) X Irradiation of Mice and Primary Factors Involved

1955 ◽  
Vol 28 (333) ◽  
pp. 495-507 ◽  
Author(s):  
Herman C. Mason ◽  
Beryl T. Mason ◽  
Walter S. Moos
Keyword(s):  
Total Head ◽  
X Irradiation
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