Thesis (M.S. in Operations Research)--Naval Postgraduate School, September 1970. / Thesis Advisor(s): Taylor, James G. "September 1970." Description based on title screen as viewed on May 25, 2010. DTIC Descriptor(s): (Kill Probabilities, Mathematical Models), Reviews, Targets, Vulnerability, Probability Density Functions, Impact Prediction, Projectiles, Explosion Effects, Bibliographies, Theses. DTIC Identifier(s): Salvos, Hit Probabilities. Includes bibliographical references (p. 36-38). Also available in print.

The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

Dynamic modeling of the atmospheric flight mechanics of a projectile equipped with an uncontrolled internal rotating disk is investigated and a modified projectile linear theory is established. It is shown through modeling of this type of projectile that several coefficients of the epicyclic dynamics are altered, leading to changes in the fast and slow epicyclic modes. A study of the frequency and damping properties of the epicyclic modes is conducted by systematically varying disk orientation, location, mass, and rotational speed. It is shown that the presence of an internal rotating disk can cause substantial changes in the epicyclic dynamics, suggesting the potential of a rotating internal part as a possible control mechanism. A further study considers the active trajectory control of a projectile using a mass unbalance, created by the radial orientation of an internal part. To evaluate the potential of this concept, a seven degree-of-freedom flight dynamic model of a projectile equipped with an internal part is defined. It is shown that by holding the internal part fixed with respect to a non-rolling reference frame, predictable trajectory changes are generated including predictable impact point changes. It is also shown that using the same control mechanism and destabilizing the projectile by fundamentally altering the inertia and, or aerodynamic properties of the projectile can lead to greater control authority. / Graduation date: 2005

Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions. It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a projectile for SIMS. The secondary ion yields (i.e., the number of secondary ions detected per projectile impact) from impacts of 10-26 keV C24H12+, C60+, gramicidin S+ and C60F40+ projectiles were examined to compare the effectiveness of the projectiles. The [M-H]- secondary ion yields from several organic samples varied inversely with the molecular weight. Multiple ion emission decreases monotonically as a function of the number of secondary ions emitted per impact and varies with impact energy such that higher energies produce more multiple ion emission. The emission of CN- from biological samples as a function of carbon-based projectile characteristics was examined to explore the possibility of using CN- as a molecular identifier. CN- emission was found to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic energy, and a second in which the F atoms deposited most of the initial kinetic energy into the surface before being ejected. The [M-H]- secondary ion yield of gramicidin S was increased ~ 15 times by embedding the analyte in a matrix of sinapic acid. These results show the optimum carbon based projectile for a given sample is dependent upon the signal to be monitored from the surface. The results also show CN- has potential as a molecular identifier. Additionally, the detection of re-emitted F- confirms prior predictions of re-emitted projectile atoms.

Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions. It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a projectile for SIMS. The secondary ion yields (i.e., the number of secondary ions detected per projectile impact) from impacts of 10-26 keV C24H12+, C60+, gramicidin S+ and C60F40+ projectiles were examined to compare the effectiveness of the projectiles. The [M-H]- secondary ion yields from several organic samples varied inversely with the molecular weight. Multiple ion emission decreases monotonically as a function of the number of secondary ions emitted per impact and varies with impact energy such that higher energies produce more multiple ion emission. The emission of CN- from biological samples as a function of carbon-based projectile characteristics was examined to explore the possibility of using CN- as a molecular identifier. CN- emission was found to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic energy, and a second in which the F atoms deposited most of the initial kinetic energy into the surface before being ejected. The [M-H]- secondary ion yield of gramicidin S was increased ~ 15 times by embedding the analyte in a matrix of sinapic acid. These results show the optimum carbon based projectile for a given sample is dependent upon the signal to be monitored from the surface. The results also show CN- has potential as a molecular identifier. Additionally, the detection of re-emitted F- confirms prior predictions of re-emitted projectile atoms.

No description available.

Thesis (Ph.D.)--Michigan State University. Dept. of Mechanical Engineering, 2008. / Title from PDF t.p. (viewed on July 22, 2009) Includes bibliographical references. Also issued in print.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 52-53). Also available on the World Wide Web.

Cluster ToF-SIMS (time-of-flight secondary ion mass spectrometry) operated in the event-by-event bombardment/detection mode has been applied to: 1) evaluate and screen the manufacturing quality of step-wise prepared micropatterned biointerfaces; 2) quantify the binding density of Au nanoparticles (AuNPs)-antiCD4 conjugates selectively attached on the cell surface; 3) elucidate the biological interaction of proteins and molecules by quantifying the fractional coverage of immobilized biomolecules; 4) enhance the accuracy of secondary ion identification of specific molecules. Briefly, our method consists of recording the secondary ions, SIs, individually emitted from a single projectile impact (C60 1,2+, Au400 +4). From the set of individual mass data, we select events where a specific SI was detected. The selected records reveal the SIs co-ejected from the nanovolume impacted by an individual cluster projectile from an emission area of 10-20 nm in diameter and an emission depth of 5-10 nm. The approach for quantifying the number of AuNPs or that of specific nanodomains is via the concept of the fractional coverage. The latter is the ratio of the effective number of projectile impacts on a specified sampling area (Ne) to the total number of impacts (No). The methodology has been validated with the determination of the number of antibody-AuNP conjugates on a cell, i.e. the number of disease related antigens on a cell via their specific binding sites with the AuNP-labeled antibodies. The number of AuNP-antibodies measured, ~42000 per cell, is in good agreement with literature results. The fractional coverage concept was also used to quantify several variants of biointerfaces. An example is the quantification of biotin and avidin immobilization as a function of the composition of silane substrates. The data collected in the event-by-event bombardment/detection mode expands the scope and quality of analytical information. One can identify SIs co-emitted with two specified SIs (double coincidence mass spectrometry) to inspect a specific stratum of a biointerface. A further refinement is the selection of events meeting a double coincidence emission condition. This mode enables the identification of nano-object of a few nm in size, which eliminates (anticoincidence) interferences from substrates.

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