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No description available.

No description available.

No description available.

No description available.

A numerical analysis of the performance of compact pin-fin array heat exchangers was carried out using water and JP-4 fuel as the working fluids. Three different configurations were used with hydraulic diameters ranging from 0.137 to 0.777 mm, and volumetric area densities varying between 4.5 and 14.5 mm2/mm3. Numerical simulations were carried out to determine the performance of each heat exchanger over a series of Reynolds numbers in both the laminar and turbulent flow regimes. It was found that very large heat transfer coefficients (in the kW/m2K range) can be achieved compared to air for the same footprint. In addition, the simulations were used to predict the Reynolds number range for transition from laminar to turbulent flow which was found to vary depending on the compactness of the heat exchanger configuration. As a final point, this study also investigated the effects of boiling of the liquid within the heat exchanger on its performance. It was found that despite improved heat transfer rates due to latent heat removal, vapor formation and resulting fluid expansion effects could result in undesirable flow patterns at low Reynolds numbers. The results from this study would be useful in the design of micro-scale heat exchangers for applications in the micro-electronic and gas turbine industries. / US Navy (USN) author.

A set of definitions, theorems and proofs to describe the Laplace transformation.

In this thesis we consider integrals of a certain class of interval functions. Specifically we consider a nondegenerate number interval [a,b], a real valued function m, defined and nondecreasing on [a,b], and the set Hm, of real valued functions f, defined on [a,b] such that: 1) f(a)=0; 2) for each subinterval [p,q] of [a,b], if m(q)-m(p)=0, then f(q)-f(p)=0; and 3) the set of all sums of the form Σ(Δf)2/Δm for subdivisions D of [a,b] is bounded above.

Stark's Conjectures were formulated in the late 1970s and early 1980s. The most general version predicts that the leading coe cient of the Maclaurin series of an Artin L-function should be the product of an algebraic number and a regulator made up of character values and logarithms of absolute values of units. When known, Stark's conjecture provides a factorization of the analytic class number formula of Dirichlet. Stark succeeded in formulating a \re ned abelian" version of his conjecture when the L-function in question has a rst order zero and is associated with an abelian extension of number elds. In the spirit of Stark, Rubin and Popescu formulated analogous \re ned abelian" conjectures for Artin L-Functions which vanish to arbitrary order r at s = 0. These conjectures are identical to Stark's own re ned abelian conjecture when restricted to order of vanishing r = 1. We introduce Popescu's Conjecture C(L=F; S; r): We prove Popescu's Conjecture for multiquadratic extensions when the set of primes S of the base eld is minimal given minor restrictions on the S-class group of the base eld. This extends the results of Sands to the case where #S = r + 1. We present three in nite families of settings where our methods allow us to verify Popescu's conjecture. We formulate a conjecture that predicts when a fundamental unit of a real quadratic eld must become a square in a multiquadratic extension.

Approved for public release, distribution unlimited / An investigation of vortex shedding downstream of a cascade of compressor stator blades, at off-design inlet-flow angles of 35, 33 and 31 degrees and Reynolds numbers, based on chord length, of 625,000, 750,000 and 800,000 is reported. The objective of the study was to characterize the flow and vortex shedding through blade surface pressure measurements and hot-wire anemometry. Vortex shedding was determined to be a leading edge phenomenon as periodic shedding was only detected on the pressure side of the wake. The relationship between vortex shedding frequency and Reynolds number was nearly linear. The vortex shedding frequency at three incidence angles was observed to be quite similar at lower Reynolds number (i.e. 450,000 and below) but developed into a larger scatter at higher Reynolds number. Similarly, the Strouhal numbers were observed to be fairly consistent (0.22 to 0.24) at low Reynolds number and more scattered (0.18 to 0.25) with increasing Reynolds number. The result obtained was comparable to the experimental results obtained by Roshko[Ref. 14], for vortex shedding behind a circular cylinder. / Major, Republic of Singapore Air Force