摘要:

A specially designed titanium dilatometer for measuring densities of liquids and solutions from room temperature to 400°C and at pressures to 352 kg/cm2has been built and operated. The liquid volume of a weighed solution of known composition is determined by taking an x‐ray photograph to show the position of the vapor‐liquid interface in the calibrated section of the dilatometer. The density is then calculated after correction for mass transfer between the liquid and vapor states. The furnace assembly and accompanying instrumentation were designed and constructed to maintain the entire length of the dilatometer in an essentially isothermal state at each temperature, and to permit an accurate, representative measurement of the temperature and pressure. The density of water was determined from room temperature and pressure to the critical point. The results agreed to within an average accuracy of 1.0% with the most recent steam table values; considerably better agreement was obtained at lower temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1684176

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A rotating cylinder viscometer is described which depends for its operation upon measuring the frequency of a periodic flow. Compared with viscometers in common use, the results of this instrument are influenced to a smaller extent by end effects, difficulties of adjustment, or the requirement for high precision parts of special materials. It features ease of construction and maintenance, the adaptability to continuous sampling and monitoring, and a precision of about 0.3% in the measurement of the kinematic viscosity. The sensitivity of the apparatus to various aberrations is illustrated. Design considerations and attainable performance standards are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1684177

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A technique for measuring the voltage coefficient of resistance associated with precision film resistors is discussed. A standard dc method is used to measure the resistance at various currents. Temperature changes due to Joule heating are minimized by submerging the resistor in a boiling liquid so that most of the power is dissipated in supplying the heat of vaporization to the liquid rather than in changing its temperature. Examples are given which show that increasing temperatures cause positive changes in resistance while increasing voltages produce negative changes. This indicates that the effects due to temperature and voltage are indeed separated. A variation of the basic measuring technique is discussed whereby, within reasonable approximations, voltage coefficients can be recorded automatically.

ISSN:0034-6748    

DOI:10.1063/1.1684178

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Quasifree scattering of electrons on bound electrons gives direct information on the electronic wave functions in atoms and molecules, if the incoming energy is definitely higher than the electron binding energy. To tackle this new line of research the two outcoming electrons, whose energies are typically in the 0.1–10 keV range, have to be detected with good energy resolution and short resolving time. These technical problems have been solved by using two hemispherical electrostatic analyzers (&Dgr;E/E≃±0.4%) and two Channeltrons as detectors; the measured FWHM resolving time is 4.3 nsec. Energy spectra are presented, in which the peak due to K electrons in carbon is well resolved.

ISSN:0034-6748    

DOI:10.1063/1.1684135

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

This paper describes an apparatus for applying simultaneously or alternately forced vibrations in tension and torsion on viscoelastic samples. The measurements can be made on unstrained or strained samples within a frequency range from 0.01 to 10 Hz. The temperature control of the sample is achieved either in an air circulating chamber or in a liquid environment. Typical results of measuring the dynamic moduli of a carbon black filled rubber in tension and shear are presented. The complex Poisson's ratio of filled rubber was calculated from its dynamic moduli as a function of strain.

ISSN:0034-6748    

DOI:10.1063/1.1684136

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

An instrument is described which enables direct mass determinations in the range 10−5–10−11g and can be modified to provide greater mass sensitivity if desired. The principle involved is that of an electrostatically driven oscillating thin fiber, clamped at one end and free at the other, which changes its resonant frequency when mass is added to the free end. The over‐all electromechanical design eliminates many of the disadvantages of more conventional microbalances and surpasses them in sensitivity and accuracy.

ISSN:0034-6748    

DOI:10.1063/1.1684137

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Servostabilizers used with Ge(Li) &ggr;‐ray spectrometers are frequently referenced to pulser peaks obtained by injecting the output of a stable pulse generator into a charge sensitive preamplifier via a small capacitor. A 1 pF charge injection capacitor has been developed that meets the requirements of high resolution spectrometers. The three terminal air capacitor has a coaxial structure with electrodes made of Kovar. It has a temperature coefficient ranging from −1 to +6 ppm/°C and a long term stability of ±20 ppm, i.e., less than ±0.1 channel out of 4000. It adds only 1 pF of stray capacitance to ground at the preamplifier input and the noise added with 3 kV across it is negligible.

ISSN:0034-6748    

DOI:10.1063/1.1684138

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A rebound resilience apparatus was developed to study the dynamic mechanical properties of polymeric materials from −196 to +180°C. Resilience data at a frequency of about 3500 Hz are obtained by measuring ball velocity near the sample with a photoelectric device. Frequency of impact is estimated using a microphone pickup. The results are recorded automatically with a data acquisition system designed for the test. The apparatus is virtually automatic in operation and has wide flexibility in sample configuration, temperature range, and temperature control. The results can be related to other dynamic mechanical properties data, and estimates of Young's modulus in the regions of high resilience can be made.

ISSN:0034-6748    

DOI:10.1063/1.1684139

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A vacuum apparatus is described to measure the interfacial adhesion of uniaxially loaded metal surfaces. Integral abrasion and ion beam bombardment devices for removing surface contaminant films in vacuum prior to interfacial contact are contained in the system. Measurements of the tensile force to rupture contact weldments in copper showed that the adhesion strength varied with the effectiveness of surface oxide removal and with the applied compressive contact stress and corresponding deformation strain. The interfacial electrical contact resistance was observed to decrease substantially with increasing adhesion.

ISSN:0034-6748    

DOI:10.1063/1.1684140

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The design and operation of a calorimetric system for the measurement of high temperature enthalpy by the method of mixtures, or ``drop method,'' is described. Features of the system are (1) an electron beam heated furnace, with sample temperatures determined by optical pyrometry, (2) a copper block calorimeter with calorimeter temperatures obtained by quartz crystal thermometry, and (3) provision for pneumatic acceleration of the sample from the furnace into the calorimeter to minimize heat losses during the transfer. The system has been used to measure the enthalpy of tungsten in the temperature range 1300–1900 K. Values agree with literature data to ±0.5%.

ISSN:0034-6748    

DOI:10.1063/1.1684141

出版商:AIP    

年代:1969

数据来源: AIP