A knowledge of the mechanical behavior of geologic materials (rocks and minerals) has become increasingly important in mining and civil engineering, geology, geophysics and more recently in a number of defense and aerospace fields. This research describes an investigation of one particular aspect of the mechanical behavior of these materials namely the determination of their inelastic properties. The investigation consisted of two stages; first, the development of suitable test facilities and experimental techniques, and second, the detailed study of the deformation properties of a relatively simple geologic materials namely, Wombeyan marble. / Ph. D.

A variational energy calculation for an N-particle boson system has been performed. A two-body Hamiltonian, containing the phenomenological Lennard-Jones 6-10 potential, has been assumed, and the parameters of the Lennard-Jones potential have been chosen appropriate for liquid helium II. The trial wave function was assumed to be of the Jastrow type with two parameters. The value of one of the parameters was chosen to satisfy a liquid-structure-factor consistency condition. The expectation value for the ground state energy is expressed in terms of a generalized normalization integral. To evaluate the 3-N fold integrals, the normalization integral is approximated by truncating its expansion. After performing the variation, the ground-state energy is expressed as a function of the reduced particle number density. The cluster approximations used were found insufficient to effect saturation. / M.S.

M.S.

Joining wooden rafters with plywood gusset plates using helically threaded nails to form roof trusses has been widely developed in recent years. Actually, the nailed member has proven to be extremely strong and stiff, but it is not perfectly rigid. The effect of non-rigidity of joints in resisting bending and thrust are investigated in this paper. The purpose of this study is to determine the rotation and slip of truss members relative to plywood gussets which influence the moment, shear, and axial load of each member. Experimental work was conducted on several timber joints in an effort to determine their actual characteristics. The theoretical analysis of relative rotation was based on the assumption that a rafter member is supported by a continuous elastic foundation; i.e. by equally spaced nails. It yields results which are reasonably close to those found experimentally. The Moire Fringe effect was introduced to measure the rotation of the wooden chords relative to the gusset plates of small model joints. A model truss with semi-rigid joints was tested. Strain were measured with SR-4 gages and deflections with dial gages The results were applied full scale designs by model analysis techniques / M.S.

Typical grain and combination grain and Livestock farms in Northeastern Virginia were selected for study of the available resources and their restrictions for harvesting, handling, drying and storing corn. The costs involved in various combinations of machinery and equipment for performing the above operations were analyzed and the proper combinations of resources under alternative resource and price conditions determined. A model for approximating the seasonal movement of prices was developed and used to predict the variability in the historical average price in the area. An enterprise budget was presented as an example for preparing budgets and estimates for specific farm situations with conditions similar to those existing in the ares of this study. Significant differences were found among the farms in the returns from the corn enterprise due to the time of sale, seasonal fluctuations in price, the quality and quantity of corn disposed, and the methods and resources used to harvest, dry, and store corn. It was found that the size of the operation, the resources available, risk and uncertainty, and timeliness must be considered in order to select a profit maximizing grain handling system. / Master of Science

In this study equations are developed for the direct determination of stiffness factor and carry-over factor for parabolic haunched beams. the conventional methods require long and tedious calculations, so the development of these equations, which require only the direct substitution of the variables, is useful. A digital computer was used to generate the data required to develop these general equations. A mathematical model was chosen for the general equation; then, by the statistical "Method of Least Squares," the coefficients in the general equation were determined. The equations were then checked against the generated data to determine average errors in calculated values. Illustrative examples are given to explain the use of the equations. / Master of Science

Neutron diffusion parameter measurements have been made at 21°C in 20, 50, and 80 percent concentrations of heavy and light water, including pure H20 and D2 0 as moderators. Pulsed neutron techniques were used with a 250-kv Cockcroft-Walton accelerator as the pulsed source. The range of bucklings used was from 0.05 cm⁻² to 0.70 cm⁻². The values for the diffusion coefficient, Dₒ; the diffusion cooling coefficient, C; and the transport mean free path, A_tr, were determined from the expansion of the decay constant to second order using iteration procedure. The values of Dₒ, C, and A_tr are tabulated below for the various concentrations, including pure H₂O and D₂O. <table style="width:100%"> <tr> <th>Percent D₂0</th> <th>Dₒ x 10⁻⁴ (cm²sec⁻¹)</th> <th>C x 10⁻⁵ (cm⁴sec⁻¹)</th> <th>λ_tr (cm)</th> </tr> <tr> <td>0</td> <td>3.634±0.048</td> <td>0.161±0.008</td> <td>0.443</td> </tr> <tr> <td>20</td> <td>3.779±0.017</td> <td>0.170±0.032</td> <td>0.515</td> </tr> <tr> <td>50</td> <td>6.964±0.044</td> <td>0.74±0.12</td> <td>0.915</td> </tr> <tr> <td>80</td> <td>11.75±0.68</td> <td>2.19±0.42</td> <td>1.602</td> </tr> <tr> <td>100</td> <td>19.66±1.37</td> <td>3.56±1.08</td> <td>2.670</td> </tr> </table> / Doctor of Philosophy

The effects of temperature on the first and second acid dissociation constants of 8-hydroquinoline (oxine) have been measured and the following thermodynamic values assigned to solutions of 0.1M strength. For the process, H₂Ox⁺ ⇋ H⁺ + HOx at 25°C., pK₁ = 5.103, ΔH = 5.7 kcal/mole, and ΔS° = -4 e.u. For the second acid dissociation constant, HOx ⇋ H⁺ + Ox⁻ at 25°C., pK₂ = 9.76, ΔH = 6.3 kcal/mole, and ΔS° = -23 e.u. The values for the second acid dissociation constant agree with those previously published. The values for the first dissociation constant have not been previously determined but are consistent with the result expected for reactions of this charge and chemical type. The partition of 8-hydroxyquinoline was determined as a function of temperature for the following systems: water-benzene, water-nitrobenzene, water-toluene, and water-chloroform. The pertinent thermodynamic values for the partitions are as follows: a. Water-benzene: log P = 2.44; ΔH = -2.0 kcal/mole; ΔS° = 4.5 e.u. b. Water-nitrobenzene: log P = 2.67; ΔH = -1.7 kcal/mole; ΔS° = 6.6 e.u. c. Water-toluene: log P = 2.33; ΔH = -1.3 kcal/mole; ΔS° = 6.2 e.u. d. Water-chloroform log P = 2.703 ΔH = -2.5 kcal/mole; ΔS° = 3.9 e.u. The values obtained for the water-chloroform system agree well with tho literature and serve as a check on the rest of the data. The effect of temperature on the overall extraction constant of nickel oxinate and ferric oxinate was measured for the system water-chloroform. The thermodynamic values found for the process Me⁺ⁿ + nHOx ⇌ MeOx_n + nH⁺ are the following at 25°C. and an ionic strength of 0.1M: a. Nickel oxinate log Kₑ = -2.73; ΔH = -40.4 kcal/mole; ΔS° = -148 e.u. b. Ferric oxinate log Kₑ = -3.97; ΔH = -14.1 kcal/mole; ΔS° = -29 e.u. The effect of ionic strength on the partition of S-hydroxyquinoline between water and benzene was determined for four different uni-univalent salts: potassium chloride, sodium chloride, potassium nitrate and sodium perchlorate. The “salting out” of oxine observed is typical of non-electrolytes. / Doctor of Philosophy

A direct method for measuring the resonance escape probability, p, in thorium-water lattices was experimentally examined. The system under investigation consisted of a square, close-packed, lattice of hollow aluminum clad thorium metal slugs (1.207 inch O.D., 0.495 inch I.D.) in. water, spaced to give a water to thorium ratio of 2 to 1 by volume (water to metal 1.45 to 1). A substitute lattice, in which the thorium was repla~ed by lead, was also used to give the same scattering properties as thorium but no resonance capture. The neutron source consisted of a fission plate made of a disc of U-235 (0.900 inch in diameter, 5 mgs in weight) mounted at the end of a Cd-covered aluminum tube which conducted a beam of neutrons from inside the thermal column of the VPI reactor into the lattice. Cd-covered indium foils were used to measure. flux traverses in two perpendicular directions, parallel to the slugs (denoted by II ) and perpendicular to the slugs (denoted by ⊥ ). 2 The curves of Ar² vs r, where A is the normalized relative activation of the foils, corrected for activation by epithermal neutrons from the primary source (reactor), were integrated to infinity and the ratio of the integrals in the thorium and lead lattices yielded p. It was found that p_⊥ and p₁₁ differed by only one percent, which was within the experimental error. It was therefore concluded that there was no anisotropy in the resonance absorption and the average of the two values, 0.88 ± 0.015, was taken as the value of p for the lattice. The experiment yielded also the age 𝛕 to indium resonance energy: In thorium lattice, 𝛕_⊥ = 44 ± 2 cm², 𝛕₁₁ = 46 ± 2 cm² In lead lattice, 𝛕_⊥ = 47 ± 2 cm², 𝛕₁₁ = 49 ± 2 cm² / Ph. D.

A topological space X is invertible at p ∈ X if for every· neighborhood U of p in X, there is a homeomorphism h on X onto X such that h(X - U) ⊆ U. X is continuously invertible at p ∈ X if for every neighborhood U of p in X there is an isotopy {h_t , 0 ≤ t ≤ 1, on X onto X such that h₁(X - U) ⊆ U. It is proved that, if X is a locally compact space which is invertible at a point p which has an open cone neighborhood, and if the inverting homeomorphisms may be taken to be the identity at p, then X is continuously invertible at p. A locally compact Hausdorff space X, invertible at two or more points which have open cone neighborhoods in X, is characterized as a suspension. A locally compact Hausdorff space X which is invertible at exactly one point p, which has an open cone neighborhood U such that U - p has two components, while X - p is connected, is characterized as a suspension with suspension points identified. Let Cⁿ be an n-conplex with invert point p. Let U be an open cone neighborhood of p in Cⁿ, and let L be the link of U in Cⁿ. Then it is shown that H_p(Cⁿ) is isomorphic to a subgroup of H_p-1(L). Invertibility properties of the i-skeleton of an n-complex are discussed, for i < n. Also, a method is described by which an n-complex which is invertible at certain points may be expressed as the union of subcomplexes, ca.ch of which is invertible at the same points. One-complexes with invert points are characterized as either a suspension over a finite set of points or a union of simple closed curves [n above ⋃ and i = 1 below that symbol], such that Sᵢ ⋂ Sⱼ = p, i ≠ j. It is proved that, if C² may be expressed as the monotone union of closed 2-cells. Also if the link of an open cone neighborhood of an invert point in a 2 - complex C² is planar, C² may be embedded in E³. / Doctor of Philosophy