scholarly journals Spectral structure of pressure measurements made in a combustion duct

1980 ◽  
Vol 68 (6) ◽  
pp. 1711-1722 ◽  
Author(s):  
J. H. Miles ◽  
D. D. Raftopoulos
Keyword(s):  
Spectral Structure ◽  
Pressure Measurements ◽  
Made In

Paper 2: Behaviour of Rarefaction Waves at the Junction of a Branched Duct

1969 ◽  
Vol 184 (7) ◽  
pp. 1-6
Author(s):  
D. H. Male ◽  
R. A. Chelsom ◽  
B. E. L. Deckker
Keyword(s):  
Method Of Characteristics ◽  
Side Branch ◽  
Pressure Measurements ◽  
Rarefaction Waves ◽  
One Dimensional ◽  
Pipe Networks ◽  
Schlieren Photography ◽  
Semi Empirical ◽  
Good Agreement ◽  
Made In

The results of an investigation into the behaviour of rarefaction waves at a junction formed by the intersection of two ducts are presented. Pressure measurements have been made in junctions in which the side branch forms an angle of 45°, 90°, and 135° with the main branch. In the 90° junction the effect of the area of the side branch to that of the main branch is examined; the values of the ratios being 1·0, 0·5, and 0·25. The amplitude of the incident rarefaction waves varies from 3 to 20 inHg. The development of the quasi-steady flow pattern has been obtained by Schlieren photography. This information, together with the pressure measurements, has been used to develop a quasi-steady, one-dimensional, semi-empirical analysis of the flow. The results of this analysis are in good agreement with the pressure measurements and can be used as boundary conditions for the examination of pipe networks by the method of characteristics.

scholarly journals Bore-Hole Survey at Dye 3, South Greenland

1984 ◽  
Vol 30 (106) ◽  
pp. 282-288 ◽  
Author(s):  
N. S. Gundestrup ◽  
B. Lyle Hansen
Keyword(s):  
Internal Friction ◽  
Surface Temperature ◽  
Ice Core ◽  
Fluid Pressure ◽  
Hole Diameter ◽  
Slight Reduction ◽  
Pressure Measurements ◽  
Overburden Pressure ◽  
The Holocene ◽  
Made In

AbstractIn 1983 three directional surveys were made in the bore hole from which a deep ice core was obtained in the summers of 1979–81. The inclination and azimuth of the bore hole were measured on three surveys, temperature was included on two surveys, fluid pressure and hole diameter on one of the surveys. Fluid-pressure measurements show that the ice-overburden pressure was undercompensated in the upper few hundred meters and overcompensated at the bottom of the hole. Diameter measurements show closure in the upper portion and expansion near the bottom beginning at the transition from the Holocene to Wisconsin ice at 1784 m. The hole expansion and increase in inclination correlate with dust and silt content in the Wisconsin ice. Changes in azimuth are due to flow of the ice and are consistent with the direction of flow at the surface. Temperature measurements show that the hole is at or near equilibrium. The gradient of 0.012 K/m below 1400 m is less than the 0.018 K/m at Camp Century. There is a slight reduction in gradient near the bottom from internal friction in the silty ice.

Lower esophageal sphincter pressures and serum gastrin levels after cholinergic stimulation

1976 ◽  
Vol 231 (4) ◽  
pp. 1250-1253 ◽  
Author(s):  
RH Higgs ◽  
TJ Humphries ◽  
DO Castell ◽  
JE McGuigan
Keyword(s):  
Lower Esophageal Sphincter ◽  
Serum Gastrin ◽  
Pressure Measurements ◽  
Cholinergic Stimulation ◽  
Subcutaneous Injections ◽  
Basal Serum ◽  
Esophageal Sphincter ◽  
Human Gastrin ◽  
Made In

To define the role of gastrin, if any, in the response of the lower esophageal sphincter (LES) to bethanechol, serum gastrin determinations and LES pressure measurements were made in controls, patients with vagotomy and antrectomy (V&A), and patients with vagotomy and pyloroplasty (V&P). Despite significant differences in mean basal serum gastrin levels no differences were found in mean resting LES pressures among these groups. In controls significant increases in LES pressure occurred after subcutaneous bethanechol, but serum gastrin levels did not change from basal values. Subcutaneous injections of bethanechol produced significantly greater increases in LES pressures in V&P patients than in V&A patients. Serum gastrin levels did not change in either group; however, background serum gastrin concentrations were significantly greater for V&P patients than V&A patients throughout the study. Intravenous infusion of human gastrin I heptadecapeptide in controls significantly increased sphincter responses to bethanechol. Thus, these studies provide evidence to suggest that the LES response to bethanechol is affected by background serum gastrin levels.

Molecular weight of an extremely hydrophobic protein, zein, in dimethylformamide and in formamide

1976 ◽  
Vol 54 (2) ◽  
pp. 196-199 ◽  
Author(s):  
Laurence A. Danzer ◽  
E. Douglas Rees
Keyword(s):  
Molecular Weight ◽  
Osmotic Pressure ◽  
Protein Concentration ◽  
Average Molecular Weight ◽  
Water Soluble ◽  
Nonaqueous Solvents ◽  
Pressure Measurements ◽  
Number Average Molecular Weight ◽  
Commercial Preparation ◽  
Made In

Both alpha zein purified from a commercial preparation and beta zein prepared fresh from corn are soluble in the nonaqueous solvents formamide and dimethylformamide; in this regard zein resembles water soluble proteins such as insulin, ribonuclease, and lysozyme. On the basis of osmotic pressure measurements made in both formamide and dimethylformamide, alpha zein has a number average molecular weight of 21 000 – 24 000 daltons and shows no tendency to aggregate or dissociate. Beta zein exists in an aggregated state (dimer and higher forms) in dimethylformamide. Formamide dissociates the beta zein dimer into monomer units but aggregation to higher species occurs with increasing protein concentration.

Laminar Burning Speed Measurements of Premixed JP-8, Oxygen and He Flames

2006 ◽  
Author(s):  
Farzan Parinejad ◽  
Edwin Shirk ◽  
Kian Eisazadeh Far ◽  
Hameed Metghalchi
Keyword(s):  
High Temperatures ◽  
Power Law ◽  
Flame Structure ◽  
Cylindrical Vessel ◽  
Pressure Measurements ◽  
Pressure Data ◽  
Spherical Vessel ◽  
Combustion Pressure ◽  
Made In ◽  
Laminar Burning Speed

The focus of this study is the calculation of the laminar burning speed of JP-8, oxygen, and helium mixtures at high temperatures and pressures. Two constant volume combustion vessels were used for the analysis. The spherical vessel was primarily used for the collection of pressure data from which the burning speed was calculated. A cylindrical vessel was also used in conjunction with a shadowgraph system to observe the flame structure and the onset of instability. Observations of JP-8 with both nitrogen and helium as diluents were made in the cylindrical vessel and it was seen that at a temperature of 200° C over the range of 1-8 atmospheres pressure and equivalence ratios of 0.7-1.0 with helium as the diluent, the flame was laminar throughout its combustion. Pressure measurements of JP-8 and oxygen with helium as the diluent were then made in the spherical vessel. Laminar burning speed of JP-8 with oxygen and helium has been calculated using the spherical vessel pressure data for this range of temperatures, pressures and equivalence ratios. Power law correlations for burning speeds have been developed for these results.

Cerebrospinal fluid pressure measurements and radioisotope cisternography in dogs

1974 ◽  
Vol 8 (1) ◽  
pp. 85-91 ◽  
Author(s):  
G. Novak ◽  
Carole Digel ◽  
B. Burns ◽  
A. Everette James
Keyword(s):  
Animal Model ◽  
Cerebrospinal Fluid ◽  
Fluid Flow ◽  
Fluid Pressure ◽  
Cerebrospinal Fluid Pressure ◽  
Communicating Hydrocephalus ◽  
Pressure Measurements ◽  
Cerebrospinal Fluid Flow ◽  
The Mean ◽  
Made In

Cerebrospinal fluid pressure measurements and radioisotope cisternograms were made in 16 mongrel random-source dogs (beagle breed excluded) as a screening technique in developing an experimental animal model for communicating hydrocephalus. Cerebrospinal fluid pressure measurements were made by puncturing the cisterna magna with a spinal needle through which the radiopharmaceutical was also subsequently injected. The mean cerebrospinal fluid pressure was 117 mm water, and the incidence of hydrocephalus was found to be rare. Cisternographic flow patterns also indicate that cerebrospinal fluid flow and absorption in dogs differs from that found in man.

Modelling of Air Flow in Impacted Polyurethane Foam

2002 ◽  
Vol 21 (5) ◽  
pp. 343-368 ◽  
Author(s):  
N.J. Mills ◽  
G. Lyn
Keyword(s):  
Stress Distribution ◽  
Flow Resistance ◽  
Air Flow ◽  
Air Pressure ◽  
Impact Response ◽  
Pressure Measurements ◽  
Uniform Stress ◽  
Total Stress ◽  
Difference Model ◽  
Made In

Polyurethane (PU) chip foam was characterised for air flow resistance, using a modification of the BS 4443 method, and for compressive impact response. A finite difference model was developed for the air flow in the impacted foam, including the effects of strain on foam permeability. It successfully predicted a non-uniform stress distribution across foam block of diameter > 100 mm, and showed that air flow is responsible for some but not all the hysteresis in this distribution for impact velocities > 3 m/s. Air pressure measurements, made in narrow vertical cavities inside impacted blocks of the foam, confirm the air pressure contribution to the total stress.

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