Graham studies

Pinto-Graham Pinto and Graham studied multicomponent diffusion in electrolyte solutions. They focused on the Stefan-Maxwell equations and corrected for solvation effects. They achieved excellent results for 1-1 electrolytes in water at 25°C up to concentrations of 4M. 

L. S. Bark and J. T. Graham, Studies in the relation ship between molecnlar structure and chromatographic behaviour, J. Chromatogr. 23 417-442 (1966) J. Chro-matogr. 25 357-366 (1966). 

The Process of Effusion One of the early triumphs of the kinetic-molecular theory was an explanation of effusion, the process by which a gas escapes from its container through a tiny hole into an evacuated space. In 1846, Thomas Graham studied this process and concluded that the effusion rate was inversely proportional to the square root of the gas density. The effusion rate is the number of moles (or molecules) of gas effusing per unit time. Because density is directly proportional to molar mass, we can state Graham s law of effusion as follows the rate of effusion of a gas is inversely proportional to the square root of its molar mass,... 

In the mid-1800s, the Scottish chemist Thomas Graham studied the effusion and diffusion of gases. The above equation is a mathematical statement of some of Graham s discoveries. It describes the rates of effusion. It can also be used to find the molar mass of an unknown gas. Graham s law of effusion states that the rates of effusion of gases at the same temperature and pressure are inversely proportional to the square roots of their molar masses. 

Note Some of Grahame s values for and included in this table. For a common cation, the sequence of anions in order of increasing adsorption is similar to that of the Hofmeister series in coagulation studies, and it is evident that specific adsorption properties are involved. 

Graham-Uranoff They studied multicomponent diffusion of electrolytes in ion exchangers. They found that the Stefan-Maxwell interaction coefficients reduce to limiting ion tracer diffusivities of each ion. 

The PVFj gauge has been calibrated up to 4 GPa (Bauer, 1984) for both shock loading and release. Graham and Lee (1986) have extended these calibration studies to about 20 GPa, and have measured both a shock loading and release profile in sapphire at 12 GPa, as indicated in Fig. 3.15. 

Graham, R.A., Impact Techniques for the Study of Physical Properties of Solids Under Shock-Wave Loading, J. Base Engrg. Trans. ASME 89, 911-918 (1967). 

Contact mechanics, in the classical sense, describes the behavior of solids in contact under the action of an external load. The first studies in the area of contact mechanics date back to the seminal publication "On the contact of elastic solids of Heinrich Hertz in 1882 [ 1 ]. The original Hertz theory was applied to frictionless non-adhering surfaces of perfectly elastic solids. Lee and Radok [2], Graham [3], and Yang [4] developed the theories of contact mechanics of viscoelastic solids. None of these treatments, however, accounted for the role of interfacial adhesive interactions. 

There are numerous reviews of the various aspects of shock-compression science a large number of the references were collected and summarized in Davison and Graham [79D01]. Those general reviews summarized in Table 1.1 provide an extensive source of concepts and data on materials response, and the serious student should study them carefully. 

This loss of shear strength was confirmed as typical of other strong solids in mechanical response studies of shock-compressed sapphire by Graham and Brooks [71G01]. In this ease there was a substantial reduction, but not... 

Fig. 3.6. The accelerations achieved at low pressure with waves transmitted through various thicknesses of fused quartz (GE 151 and Dynasil 1000) have been carefully studied and can serve as standard loadings (after Graham [79G02]). Recent data from Smith [92S01] also show the particle velocity limit for the linear acceleration to be 0.11 kms ...

The piezoelectric behavior of both quartz and lithium niobate has been studied in a series of careful, systematic investigations. (See Graham and coworkers [65G01, 70101, 75G04].) The experimental arrangement is shown Fig. 4.2. The impactor, preferably the same material as the piezoelectric sample (but perhaps another standard material), is accelerated to a preselected... 

Fig. 4.2. The technique used to study the piezoelectric behavior of the crystals quartz and lithium niobate used controlled, precise impact loading. The impact velocity can be measured to an accuracy of 0.1%, leading to the most precisely known condition in shock-compression science (after Davison and Graham [79D01]).

The effect of shock-induced conduction is less distinct in ferroelectrics than in piezoelectrics but is nevertheless apparent from a number of studies. (See Davison and Graham [79D01] and Novitskii [79N03].) Differences in conduction with sample polarity, such as those seen in quartz but of opposite sign, are observed in ferroelectrics. 

Fig. 5.11. The study of shock compressibility of pressure-sensitive magnetic alloys was carried out with the quartz gauge impact technique. Loading was either with the specimen material or a quartz gauge. Resulting stress pulses were recorded with a quartz gauge (after Graham et al. [67G01]).

The shock-compression induced structural phase transformation in iron from the low pressure bcc phase to the high pressure hep phase is one of the most visible problems studied in shock-compression science, and its discovery was responsible for widespread recognition of the capabilities of the high pressure shock-compression experiment. The properties of many shock-induced phase transitions are summarized in Duvall and Graham [77D01]. 

Fig. 5.21. The shock-induced polarization of polymers as studied under impact loading is shown. For the current pulse shown, time increases from left to right. The increase of current in time is due to finite strain and dielectric constant change. (See Graham [79G01]).

Fig. 5JS2. Shock-induced polarization of polymers has been studied by many investigators, with data as summarized. The typical behavior indicates a threshold compression of about 10%-15% followed by a rapid increase in value. The polarizations shown vary over three orders of magnitude. The author has proposed a mechanically induced bond-scission model to describe the effects. (See Graham [79G01].)...

The high explosives, baratol or Composition B-3, are used to produce the plane wave loading into the driver plates. These explosives have been widely studied in substantial work at Los Alamos. Plane waves are introduced into the explosive pads with either P-22 or P-40 plane-wave generators developed at Los Alamos. The Bear system is based on the 56 mm diameter of the P-22, while the larger sample size Bertha system is based on the 102 mmdiam of the P-40. More details on sample dimensions are reported by Graham [87G03]. 

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