K. Mahabir ... [et al.]. / Cover title. / Includes bibliographical references (leaf 9). / Work partially supported by DEC. Work partially supported by the Air Force Office of Scientific Research. AFOSR-88-0032 Work partially supported by the MIT/Industry Power Electronics Collegium.

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Domestic chicks were tested for initial response, approach, and stay-near tendencies during one 5-minute test exposure to a distant audio-visual 1mprinting apparatus. Significant interline differences demonstrated genetic variation. A bidirectional selection program was initiated with time to respond as the selected trait. Approach and stay-near tendencies were measured as associated traits. Results through the F4 generation disclosed that in the fast response line the realized heritability of the selected trait was .32 and the correlated realized heritabilities for time to approach and for time spent near the apparatus were .36 and .32, respect1vely. In the slow response line selection was ineffective, and heritabilities for the three traits were zero. Genetic and phenotypic relationships among the traits were high in the fast response line, but genetic relationships in the slow response line could not be determined because of the zero heritabilities. The asymmetrical response to selection could not be explained by the usual causes, and it is hypothesized that responsiveness is a threshold trait. Comparisons of 290 purebred chicks with 379 crossbred chicks for response, approach, and stay-near tendencies provided evidence of heterosis. This demonstration of non-additive effects implies fitness roles for these traits and supports the idea that they indicate imprinting tendencies. Time of day tested, sex, hatch, mating type, developmental age, and 24-hr body we1ght were considered independent variables influencing the behavior traits. Multiple regressions showed that the initiation of responsiveness is not predictable. However, once a chick responded, its behavior was highly predictable; this supports the hypothesis from the selection experiment that responsiveness is a threshold trait. Sensory modalities involved in satiating the behavior traits were differentiated by comparisons of non-handled chicks with those exposed to visual, tactile, and visual - plus-tacti1e stimuli just prior to testing. Visual stimulation alone increased responses and approaches, whereas tactile stimulation alone had no effect on these behaviors. Tactile-plus-visual stimulation just prior to testing inhibited response and approach tendencies. Eva1uation of the effects of prior socialization and handling indicated that isolation enhanced approach responses, and that prior handling had the opposite effect. An age and/or memory factor was introduced when chicks were handled in the light at times other than just prior to testing. Handling at 5 and 9 hours had no effect on the approach response, whereas handling at 13, 17. or 23 hours post-hatching decreased such responses. Results were explained on a drive satiation hypothesis. / Ph. D.

This dissertation contains a study of related topics connected with the one-dimensional random walk which proceeds by steps of ±1 occurring at random time intervals. In general it is assumed that these intervals are identically and independently distributed. This model may be specialized to the queuing process by inserting a reflecting barrier at the origin so that the displacement S(t) of the random walk at any time t is non-negative. Throughout most of the dissertation it is assumed that the time intervals between steps of the same kind are independently and negative exponentially distributed with non-time- dependent parameter λ for positive steps, and μ for negative steps. Under this assumption we designate the single-server queuing process by the usual notation M/M/l. Using an obvious extension to the queuing notation, we denote by –2/M/M the unrestricted walk in which S(t) may range over the entire set of positive and negative integers including zero. Topics of classical interest are discussed such as first-passage times, first maxima, the time of occurrence of the rth return to zero, and the number of returns to zero during an arbitrary time interval (0,t). In addition to the discussion of these topics for ∞²/M/M and M/M/1, probability density functions are obtained for the first-passage times and the epoch of the maximum on the assumption that time intervals between steps of +1 have a general distribution and steps of -1 occur in a Poisson stream and vice-versa. These more general expressions are new. Special emphasis is placed on the two-state sojourn problem in which it is assumed that at any time t, S(t) belongs to one of two possible states, A and B. The distribution of the sojourn time σ_B(t) in a given state B during the arbitrary time interval (0,t) is given. The general result for the distribution of σ_B(t) is applied to the M/M/I queuing process to obtain the distribution of the busy time. A similar application is made to the walk ∞²/M/M to obtain the distribution of σ_B(t) for the two cases: (i) B is the set of all non-zero integers; and (ii) B is the set of all positive integers. New expressions are given the distribution function of σ_B(t) in all three cases. New asymptotic formulae for these cases are derived and compared numerically with those obtained by Takacs using different methods. For the more difficult sojourn time problem assuming three possible states, A, B₁, and B₂, the joint probability density function of σ_A(t) and σ_B₁(t) is derived. This result, not published before, is applied to –2/M/M assuming that A contains zero only and that B₁ and B₂ consist of the sets of positive and negative integers, respectively. The dissertation also includes a discussion of several results by E. Sparre Andersen concerning fluctuations of sums of random variables and their time-dependent analogues. / Ph. D.

Microsomes obtained from different groups or rats, following pretreatment with different dosages or 3,4-benzpyrene (BP), aflatoxin Bl (Bl), ethionine (ET) and/or a combination of these, were used to obtain initial velocity data for BP disappearance. The values for Km, Vmax and K/v for different groups were obtained by the computer analysis of initial velocity data. Vmax and Km values were used to assess the quantitative and qualitative changes of microsomal B:2 hydroxylase, respectively, caused pretreatment. BP pretreatment greatly enhanced the V and also decreased the Km values. The increase in Vmax paralleled the increase in the dosage of BP from BP(lX) to BP(3X). When ET, a protein inhibitor, was given in conjunction with BP it blocked the increase in Vmax but did not block the effect of BP on the Km. The effect of BP on the qualitative properties (Km) of enzyme was observed to be a slow time dependent phenomenon which required the simultaneous presence of both the enzyme and the inducer. / Ph. D.

Procedures are described for the routine analysis of amines and other compounds produced in bacterial cultures. Whole cultures were grown in six mls of chopped meat-glucose medium, acidified, and extracted with ethyl ether or chloroform to obtain organic acids, alcohols, ketones, aldehydes, and other neutral compounds. The residual broth was then made basic and extracted with chloroform to obtain the amines. For chromatographic analyses, alcohols and amines were converted to trifluoroacetyl derivatives. Organic acids were converted to their methyl esters. Analyses were made by a temperature- programmed gas chromatograph equipped with flame ionization detectors. Sixty-two strains of clostridia, representing 13 species, were analyzed for soluble products in whole cultures. Many amines were found and total amine concentrations exceed 0.5% (weight) in cultures of several species examined. Neutral products were found to be major products of several species. Alcohols both short and long chain were detected and were valuable in differentiation of some groups of clostridia. The 13 species were grouped as follows: on the basis of fatty acids and neutral products, 7 groups; on the basis of amine products, 10 groups; on the basis of alcohol and neutral products, 12 groups; and on the basis of amine, alcohol, and neutral products, 13 groups. / Ph. D.

A finite generalized integral transform was applied to three general classes of problems in the vibrations of continuous media. For its kernel the eigenfunction of an associated eigenvalue problem was used and the result was denoted the eigentransform. The eigentransform was applied to (1) continuous media with both non-uniform stiffness and mass distributions; (2) continuous media with uniform stiffness but non-uniform mass distribution; and (3) to problems with time-dependent boundary conditions. A general method was presented for treating vibrations of continuous media with non-uniform stiffness and mass distributions. The eigentransform was applied to the governing partial differential equation and subsequently the transformed displacement was found to satisfy an infinite set of coupled ordinary differential equations similar to those encountered in the vibrations of discrete masses. These equations led to a matrix eigenvalue problem from which approximate eigenvalues and eigenvectors were obtained. The differential equations were uncoupled using a transformation matrix of the eigenvectors and then were solved for the generalized time function. Finally, the inversion series for the transform was used to obtain the solution for the dynamic response. To illustrate the method, the first four frequencies and mode shapes were determined for the longitudinal vibration of a tapered rod. The eigentransform was used to develop a general procedure for treating continuous media with uniform stiffness but non-uniform mass distribution. These results, similar to those for the general non-uniform problem, reduced this problem to a matrix eigenvalue problem. The mode shapes were determined by summation using the eigenvectors and mode shapes for the uniform continuous media. Several problems for beams and plates with concentrated masses were solved as examples. This approach demonstrated definite computational advantages for plates over past treatments where frequency equations were determined as infinite series. Vibrations of continuous media with time-dependent boundary conditions were then treated using the eigentransform. One dimensional media were considered first and next isotropic and orthotropic plates. One-dimensional continuous media were treated in a general way by specifying a differential operator of even order in the spatial derivatives. Applications to rods and beams were presented. The vibration of isotropic plates for an arbitrary shape was treated by expressing the equations in normal and tangential coordinates. The eigentransform of the governing equation was performed using an identity and theorem of vector analysis. The time-dependent boundary conditions were allowed to have an arbitrary variation along the boundary. Detailed applications were then made to rectangular and circular isotropic plates. The eigentransform of the orthotropic plate equation was performed by integration by parts. Again the boundary conditions were permitted to vary arbitrarily around the boundary. The response of a simply supported plate with an arbitrary edge displacement was determined as an illustration. This investigation demonstrated that the eigentransform is a logical generalization of other finite integral transforms. The concept of a generalized finite integral transform extends the advantages of integral transforms to a much broader class of boundary value problems. / Ph. D.

The objective of this investigation was to determine the effect of aeration in combination with chemical coagulation on the treatment of spent vegetable tan liquor. Chemical coagulation was desirable because it effectively reduced the color and suspended solids of the tanning waste. Aeration was thought to be a possible means of reducing the Chemical Oxygen Demand of the waste by biological stripping of the pyrogallol compound in the spent waste. Samples collected from the aeration-coagulation system were periodically analyzed for Chemical Oxygen Demand, pH, suspended solids, color removal, volume of sludge produced, and coagulant demand. These values were correlated with those values obtained for the characteristics of the raw spent waste. Color reductions up to 94 per cent were obtained up to an aeration period of 12 hours with a suspended solids reduction of 96 per cent.. Chemical Oxygen Demand reductions of the waste were increased throughout the period of aeration with a maximum reduction of 40 per cent at 36 hours of aeration. Significance of the five day Biochemical Oxygen Demand value of 25,600 mg/liter for the raw spent waste indicated a 4 to 5 increase over all reported values from the literature. / Master of Science

Results are presented of an experimental and analytical investigation to determine the feasibility of using active control techniques to (1) attenuate the response of a flexible payload to low frequency sinusoidal vibration disturbances, (2) damp the transient response of a flexible payload to step disturbances, and (3) eliminate isolator static deflections under conditions of gradually changing steady acceleration levels. An active vibration isolation system was developed and an experimental working model of the system was built and tested. Digital and analog computer studies were conducted to obtain the transmissibility and transient response characteristics of the isolation system. The analytical and experimental results indicate that the active vibration isolation system is very effective in attenuating the response of a one- and two-degree-of-freedom payload to vibratory disturbances. / Master of Science

A detailed analytical model was developed to include the effect of the melting process on a porous composite which retards its own heating rate by sacrificing its infiltrant. A transient one-dimensional heat-transfer analysis was conducted considering both the heats absorbed by melting and vaporization of the infiltrant from within the matrix. A finite-thickness liquid layer was seen to exist above the composite surface as a result of the flow of liquid coolant onto the surface induced by the expansion of the coolant on melting. There existed a period of time during which the melt layer was subject to both depletion due to vaporization and renewal by the flow of liquid coolant onto the surface. As the heating process continued the melt layer was depleted and the liquid coolant vaporized from within the tungsten matrix. The analysis was solved by finite-difference techniques and programmed for the IBM 7040/1401 Digital Computing System. An extensive search was conducted to determine the dependence of temperature on the thermophysical properties of seven different metallic coolants. Data were obtained for the various infiltrants up to that time at which the melt layer vaporizes completely from above the composite surface. A fundamental understanding of the effects of the melting process and of assuming variable properties on the early stages of the self-cooling process was obtained. / Master of Science