摘要:

The collection efficiencies for sulfuric acid aerosols of 0.4‐ to 1.3‐microns particle diameter, and the resistance to flow through glass fiber mats composed of 3.5‐, 6.2‐, and 9.6‐micron fibers, were investigated experimentally. The results agree with the theory that particle collection in this range is a function of the inertia of the particles, the interception by the fibers, and the nature of the flow around the fibers, as characterized by the parameters &PSgr;,R, andNRe, respectively, and that the pressure drop is a function of the flow characteristics and the fiber interference effect. Theoretical equations for collection efficiency and pressure drop of fiber mats were analyzed in terms of the impaction efficiency and drag coefficient of single fibers. These equations were evaluated by comparing the apparent fiber efficiency and drag with theoretical values.

ISSN:0021-8979    

DOI:10.1063/1.1722328

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Spheres were fired at supersonic speeds into monatomic gases and into chlorine gas. The position of the shock wave which forms in front of the sphere depends on the Mach number and gas state before and after crossing the shock wave. Measurements of position made in monatomic gases agree fairly well with aerodynamic theory. As the shock position depends on the actual gas state attained, and thus molecular excitation times, measurements in more complicated gases than a monatomic gas can give information as to amount and rates of excitation. The vibrational energy excitation in chlorine was singled out for study. This excitation involves a well‐known rate process. By carrying out shock position measurements at several different pressures, it is possible to infer the order of magnitude of the vibrational relaxation time in chlorine; the present results are in agreement with shock tube measurements of the relaxation time.

ISSN:0021-8979    

DOI:10.1063/1.1722329

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Criticality calculations for heterogeneous reactor media are usually based on a single‐cell calculation off, the thermal utilization, followed by a ``homogenized'' treatment of the macroscopic neutron migration. A changed approach is here advocated, in which diffusion theory is applied only to the multiply‐connected moderator portions of the reactor, the fuel is treated by the use of multiplying boundary conditions, and no arbitrary averaging need be done. As an example, the one‐dimensional case of plane fuel slabs in moderator is treated, and the material buckling characteristic of the fundamental mode is obtained using two‐group theory. The equation for this case readily allows a comparison between neutron migration lengths parallel to and perpendicular to the fuel slabs: considerable anistropy is found, in magnitude greatly dependent on fuel slab separation.

ISSN:0021-8979    

DOI:10.1063/1.1722330

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Ultrasonic relaxation has been investigated in normal propyl alcohol using pulse techniques. Measurements of velocity and absorption were made at frequencies from 1 to 82 megacylces and over a temperature range 0 to −155°C. The data could be explained by assuming a distribution of relaxation times, and it was suggested that the distribution of relaxation times is but a reflection of the distribution of activation energies for the elementary molecular processes involved. A theory based on the assumption of a uniform distribution of activation energies for compressional processes and a single relaxation time for the shear process was presented. The agreement between the values calculated from this theory and the experimental data is good except at very high viscosities. The compressional viscosity calculated from the theory was found to be nearly equal to the shear viscosity except at very high viscosities. This is in agreement with the compressional viscosity calculated from the ``excess'' absorption in the nondispersion region.

ISSN:0021-8979    

DOI:10.1063/1.1722331

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The torque equation for the motion of the magnetization in a magnetized ferrite yields a component along the direction of the applied dc magnetic field. The time dependent part of this component is of second order in rf quantities and has previously been neglected. With high incident powers an observable double frequency output is predicted. A high intensity microwave magnetic field and an orthogonal dc magnetic field were applied to a ferrite body. Double frequency magnetic fields were generated in the same direction as the dc magnetizing field. A primary frequency of 3175 mc was used with peak powers up to 200 watts. The peak output power at 6350 mc was found to increase linearly with the square of the peak input power over a range of 42 db. Reasonable agreement was found between theory and experiment.

ISSN:0021-8979    

DOI:10.1063/1.1722332

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722334

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722335

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722336

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722338

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1722339

出版商:AIP    

年代:1956

数据来源: AIP