NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
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A boundary-value problem governing a three-phase concentric-cylinder model was analytically modeled to analyze<br />
annular interfacial crack problems with Love s strain functions in order to find the stress intensity factors (SIFs) <strong>and</strong> strain<br />
energy release rates (SERRs) at the tips of an interface crack in a nonhomogeneous medium. The complex form of a singular<br />
integral equation (SIE) of the second kind was formulated using Bessel s functions in the Fourier domain, <strong>and</strong> the SIF <strong>and</strong><br />
total SERR were calculated using Jacoby polynomials. For the validity of the SIF equations to be established, the SIE of the<br />
three-concentric-cylinder model was reduced to the SIE for a two-concentric-cylinder model, <strong>and</strong> the results were compared<br />
with the previous results of Erdogan. A preliminary set of parametric studies was carried out to show the effect of interphase<br />
properties on the SERR. The method presented here provides insight about the effect of interphase properties on the crack<br />
driving force.<br />
Author<br />
Concentric Cylinders; Fracture Mechanics; Singular Integral Equations; Strain Energy Release Rate; Crack Propagation<br />
20040045358 Universities Space Research Association, Huntsville, AL, USA<br />
Traveling Magnetic Field Applications for Vertical Bridgman Growth: Modeling <strong>and</strong> Experiment<br />
Mazuruk, Konstantin; [2004]; 1 pp.; In English; Fifteenth American Conference on Crystal Growth <strong>and</strong> Epitaxy, 20-24 Jul.<br />
2003, Keystone, CO, USA<br />
Contract(s)/Grant(s): NCC-866; No Copyright; Avail: Other Sources; Abstract Only<br />
Traveling magnetic fields offer a direct control of the metallic melt meridional flow in long cylinders. It induces the<br />
Lorentz body force that can counteract with the buoyancy force induced by radial temperature non-uniformity. It can<br />
significantly offset a natural convection in the system, or it can even set up the flow in opposite direction, thus affecting the<br />
interface shape, the growth rate <strong>and</strong> macrosegregation. Results of our numerical modeling of the Vertical Bridgman crystal<br />
growth of InSb will be discussed. The experimental part of this investigation will address the effect of the applied traveling<br />
magnetic fields on the interface shape of InSb crystals. Specifics of the growth apparatus design for this research will be<br />
provided in details.<br />
Author<br />
Magnetic Fields; Bridgman Method; Crystal Growth; Lorentz Force<br />
20040046137 Kestrel Technology, LLC, Moffett Field, CA, USA<br />
Static Analysis of C Programs<br />
Venet, Arnaud; Brat, Guillaume; [2003]; 13 pp.; In English; No Copyright; Avail: CASI; A03, Hardcopy<br />
Contents include the following: Motivation. Cost of losing missions. Introduction to Static Analysis:definition, defect<br />
classes, applicability issues, specialization, analysis of MPF. C Global Surveyor (CGS): fact sheet, CGS phases, example.<br />
Conclusions.<br />
Derived from text<br />
Static Characteristics; C++ (Programming Language); Costs; Losses<br />
20040047188 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA<br />
Abstract Model of the SATS Concept of Operations: Initial Results <strong>and</strong> Recommendations<br />
Dowek, Gilles; Munoz, Cesar; Carreno, Victor A.; March 2004; 46 pp.; In English; Original contains color illustrations<br />
Contract(s)/Grant(s): NCC1-02043; WU 23-786-10-10<br />
Report No.(s): <strong>NASA</strong>/TM-2004-213006; L-18361; No Copyright; Avail: CASI; A03, Hardcopy<br />
An abstract mathematical model of the concept of operations for the Small Aircraft Transportation System (SATS) is<br />
presented. The Concept of Operations consist of several procedures that describe nominal operations for SATS, Several safety<br />
properties of the system are proven using formal techniques. The final goal of the verification effort is to show that under<br />
nominal operations, aircraft are safely separated. The abstract model was written <strong>and</strong> formally verified in the Prototype<br />
Verification System (PVS).<br />
Author<br />
Mathematical Models; Safety<br />
20040047189 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA<br />
Stochastic Optimal Control via Bellman’s Principle<br />
Crespo, Luis G.; Sun, Jian Q.; December 2003; 29 pp.; In English<br />
Contract(s)/Grant(s): NCC1-02043; WBS-762-20-61-01<br />
Report No.(s): <strong>NASA</strong>/CR-2003-212419; NIA Report No. 2003-04; NAS 1.26:212419; No Copyright; Avail: CASI; A03,<br />
Hardcopy<br />
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