Pressure-diameter tests

The burst pressure test characterizes the maximum internal pressnre, the vascnlar graft resists before failnre. The bnrst test is carried ont in the hydrated state nsing a setup similar to that of the pressure-diameter test that allows the system to achieve pressures higher than the physiological range (>2000 mm Hg). 

The standard ASTM D2585 filament wound pressurized bottle test method utilizes a 0.15-m (5.75-in.)intemal diameter filament wound bottle as the test article. This standard test method (with variation in bottle sizes) has been used extensively by the rocket motor industry [47-50] to evaluate glass, aramid, and graphite fiber composite vessel performance. This test method has generally shown good results, but is a relatively expensive test method. Testing of one 0.5-m (20-in.) diameter bottle can cost up to 20K. Other disadvantages are ... 

Further, a relationship between the pressure vessel test (that assesses the pyrolitic hazard using the limited diameter (PVLD) that is considered to correspond to a rate of pressure increase during the heating process) and the improved time/pressure test applied to organic peroxides is shown in Fig.3.70. This suggests 83) a correlation between the results of the tests. 

Results of pressure vessel tests using either a 1 or a 9 mm diameter orifice plate are summarized in Table 3.35. In this instance, the applied voltage is 73 V and the heating rate is about 0.5 °C /sec in the range from 100 to 200 °C. ... 

Table 3.35 Results of pressure vessel test using plates with orifice diameters of 1 mm and 9 mm...

Table 3.36 Comparison of limit diameters of pressure vessel tests...

Flowability determinations on reactoplasts according to the method set out in ASTMD 31 23-72 (USA) involve the forming of a spiral of a specified cross-section. Use is made of a pressing machine for transfer pressing. The 20 0.1 g of the material is placed in a chamber 25.4 mm in diameter. Tests are carried out at 150 3 °C, at a pressure of 6.9 0.17 MPa, and a piston velocity of25-100 mm/s. The cross-section of the spiral formed is a half-circle with a radius of 1.6 0.5 mm. The maximum length of the spiral is 1270 mm. 

The catalytic oxidation of benzene (0.5 % in air) and n-butane (1.5 % in air) was carried out in flow reactor operated at atmospheric pressure. The tests were done on a constant catalyst volume basis (2 cm ) in a quartz reactor of internal diameter 1.0 cm. The reactions were performed in the temperature range of 300-550 C at the flow rate of 50-200 cmVmin. The analysis of the substrates and products was performed by gas chromatography. 

The melt index test measures the rate of extrusion of a thermoplastic material through an orifice of specific length and diameter under prescribed conditions of temperature and pressure. This test is primarily used as a means of measuring the uniformity of the flow rate of the material. In this study, the melt flow index (MFI) value increased from 1.35 to 1.69 g/10 min with increase in EMA content from 0 to 10% in the PMMA/EMA blends (Table 5.3). This may be due to the reduction in cohesive strength as well as the plasticizing effect of EMA in PMMA/EMA blends. However, further addition of EMA content above 10% by weight shows no more increase in MFI. 

After finishing the electrical conductivity tests, a hydraulic permeability test was performed based on ASTM D 2434-68 [14]. 10 kg of agglomerates were placed into a 19.05 cm inner diameter test column. The test set up is shown schematically in Figure 2. The agglomerated bed was flooded by introducing water from the top. The flow rate was adjusted to achieve a steady state value. A difference in pressure or head was then measured across the agglomerate bed from the attached manometer. Head as a function of various flow rates were obtained. The values of... 

Standoff distance Test gas Test Duration Nozzle diameter Test temperature Abrasive feed rate Angle of incidence Air jet pressure... 

As the contact pressure (load divided by total surface area) increases, the removal rate also increases. But the roughness (peak-to-valley height) and depth of damage increase by a similar proportion. For example, in the case of six clamped samples, each with a diameter of 25 mm, under a total load of 200 N, the contact pressure measures 0.07 N/mm. In the technical literature, however it is customary to specify only the rotational speed of the disk in rpm and the load in N instead of the removal rate and contact pressure. When testing recommendations for the preparation of polished sections, the rotational speed and load must be converted accordingly. 

Plitt took the data of Lynch and Rao and added his own, with smaller cyclones up to 150 mm diameter tested with silica flour, and used the data, 297 individual tests in total, to derive by regression analysis yet another correlation for the pressure drop-flow rate relationship, not dissimilar to the above equation. 

Di Felice et al. (1992a) investigated the validity of the full set of scaling laws for bubbling and slugging fluidized beds. They used an experimental facility that permitted the pressurization of different diameter test sections to match the scaling parameters. Minimum fluidization measurements, video measurements of bed expansion, and pressure fluctuation data were used to compare the similarity of five different bed eonfigurations. Three of the beds were scaled properly. 

For the transfer tests and liquid acquisition systems, COLD-SAT parameters from all four studies are compiled in Table A.2. Wherever parameters were not readily available, assumptions were made to derive those parameters. For example, MEOPs were determined from the anticipated maximum ranges of tank pressures during pressurization/ outflow tests. Flow rates were determined from LAD or no vent fill (NVF) subsystem requirements. Re numbers in the transfer line were determined based on total flow delivery from the LAD subsystem and the internal diameter of the pipe. Line velocities were determined using conservation of mass. 

The insulation material was wrapped onto the calorimeter in a continuous spiral. The aluminum foil was interrupted after each revolution because the conduction around the spiral would contribute significantly to the total heat transport. After the samples were wrapped on the 4-in.-diameter test and guard chambers, they were inserted into the vacuum chamber and evacuated. The inside chambers were heated electrically to about 100°C during evacuation to help drive off residual moisture in the insulation material. Each sample was heated and evacuated for about 3 days. The guard and test chambers were then filled with cryogenic fluid, either liquid N2 or H2, and the rate of evaporation of liquid was measured with a wet test meter and timer. The rate of evaporation was measured for a period of several days, until equilibrium was attained. Conditions of equilibrium were sometimes disturbed by changing barometric pressure and, therefore, we had to wait additional lengths of time to be completely certain of our results. 

A pressure distribution test in the surface of containment was done in a low velocity wind tunnel with various wind speeds, air entrances, yaw and pitch angles. The test shows that the pressure is positive in the area of -35° < 0 < 35°. The influence of wind on natural convection of containment was also done with a 1/50 integral model. The test results revealed that natural convection flow rate was enhanced in general by outside wind and horizontal wind (a = 0) had the better effect than a < 0° or a > 0°. The position of chimney might influence the air flowing around the containment. The distance between containment and chimney should be larger than 4 times of chimney diameter. However, smoke wind tunnel test showed no exhausted hot air was re-circulated under any d outside wind conditions. 

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