http://idea.library.drexel.edu/handle/1860/750 http://idea.library.drexel.edu/retrieve/4849 http://idea.library.drexel.edu/handle/1860/750 Search the Channel search http://idea.library.drexel.edu/simple-search http://idea.library.drexel.edu/handle/1860/2755 Title: Recent patents in bionanotechnologies: nanolithography, bionanocomposites, cell-based computing and entropy production <br/> <br/>Authors: Layton, Bradley <br/> <br/>Abstract: This article reviews recent disclosures of bio-inspired, bio-mimicked and bionanotechnologies. Among the patents discussed is a nanoscale porous structure for use in nanocomposites and nanoscale processing. Patents disclosing methods for printing biological materials using nanolithography techniques such as dip-pen technology are discussed, as are patents for optimizing drug design. The relevance of these technologies to disease prevention, disease treatment and disease resistance is discussed. The paper closes with a review of cell-based computing and a brief examination of how information technology has enabled the development of these technologies. Finally a forecast of the how these technologies are likely to accelerate global entropization is discussed as well as a new classification of machine types. Mon, 29 Oct 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2752 Title: The development of a biologically inspired propulsor for unmanned underwater vehicles <br/> <br/>Authors: Tangorra, James Louis; Davidson, S. Naomi; Hunter, Ian W.; Madden, Peter G. A.; Lauder, George V.; Dong, Haibo; Bozkurttas, Meliha; Mittal, Rajat <br/> <br/>Abstract: Fish are remarkable in their ability to maneuver and to control their body position. This ability is the result of the coordinated movement of fins which extend from the body and form control surfaces that can create and vector forces in 3-D. We have embarked on a research program designed to develop a maneuvering propulsor for unmanned undersea vehicles (UUVs) that is based on the pectoral fin of the bluegill sunfish. For this, the anatomy, kinematics, and hydrodynamics of the sunfish pectoral fin were investigated experimentally and through the use of computational fluid dynamics (CFD) simulations. These studies identified that the kinematics of the sunfish pectoral fin are very complex and are not easily described by traditional “rowing”- and “flapping”-type kinematics. A consequence of the complex motion is that the pectoral fin can produce forward thrust during both its outstroke (abduction) and instroke (adduction), and while doing so generates only small lateral and lift forces. The results of the biological studies were used to guide the design of robotic pectoral fins which were built as experimental devices and used to investigate the mechanisms of thrust production and control. Because of a design that was based heavily on the anatomy of the sunfish fin, the robotic pectoral fins had the level of control and degrees of freedom necessary to reproduce many of the complex fin motions used by the sunfish during steady swimming. These robotic fins are excellent experimental tools, and are an important first step towards developing propulsive devices that will give the next generation of UUVs the ability to produce and control thrust like highly maneuverable fish. Thu, 28 Jun 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2749 Title: Determination of the effective zero point of contact for spherical nanoindentation <br/> <br/>Authors: Moseson, Alexander J.; Basu, Sandip; Barsoum, Michel W. <br/> <br/>Abstract: Accurate determination of the “zero point,” the first contact between an indenter tip and sample surface, has to date remained elusive. In this article, we outline a relatively simple, objective procedure by which an effective zero point can be determined accurately and reproducibly using a nanoindenter equipped with a continuous stiffness measurement option and a spherical tip. The method relies on applying a data shift, which ensures that curves of stiffness versus contact radius are linear and go through the origin. The method was applied to fused silica, sapphire single crystals, and polycrystalline iron with various indenter sizes to a zero-point resolution of ≈2 nm. Errors of even a few nanometers can drastically alter plots and calculations that use the data, including curves of stress versus strain. Sat, 29 Dec 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2746 Title: Two-dimensional minkowski-sum optimization of ganged stamping blank layouts for use on precut sheet metal for convex and concave parts <br/> <br/>Authors: Mulero, Rafael; Layton, Bradley <br/> <br/>Abstract: As the number of parts that manufacturers need to place on a piece of material such as sheet metal increases, the need for more sophisticated algorithms for part orientation and spacing also increases. With greater part shape complexity, the ability of a skilled craftsman becomes challenged to minimize waste. Building upon the previous work of Nye, we present a Minkowski-sum method for maximizing the number of parts within gangs on a rectangular sheet of material. The example provided uses a simply shaped part to illustrate the presented method, yielding a packing efficiency of 62% that is identical to the efficiency that a skilled worker would produce without the algorithm. We also provide results for laying out a more complex part in ganged sections, demonstrating a result that would be difficult for a human to reproduce. Our work extends that of Nye by adding practical constraints such as the number of parts that can be blanked at once as well as the amount of horizontal and vertical spacing between ganged blanking sets. Additionally we add an algorithm for laying out polygons with concave geometries by separating the part into a set of convex polygons. Two examples for optimization, one of a chevron-shaped part and one of a complex shape previously used by Nye (2000) and Choi et al. (1998) are provided demonstrating the existence of a local maximum number of parts that may be stamped within a single ganged blank. Our algorithm is extendable to a program that may provide stamping manufacturers with a tool that can maximize the total number of parts stamped on stock sheet metal, or for other tiling problems. Sun, 29 Oct 2006 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2742 Title: Towards a method for printing a network of chick forebrain neurons for biosensor applications <br/> <br/>Authors: Sasoglu, F Mert; Kilinc, Devrim; Allen, Kathleen; Layton, Bradley <br/> <br/>Abstract: The primary goal of this work is to establish a robust, repeatable method for printing arrays of neurons. This work has two endpoints. One is to use a neural array as an experimental testbed for investigating neuronal cell growth hypotheses. The other endpoint is to enable the next generation of cell-based sensors. Herein we compare microcontact printing results previously published by our group with a new method of dip-pen printing. We present preliminary results for neurons growing on these microprinted arrays, assessing contact frequencies and growth characteristics. Wed, 22 Aug 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2735 Title: The effect of deformation on room temperature coulomb blockade using conductive carbon nanotubes <br/> <br/>Authors: Legum, Benjamin; Cooper, Ryan; Mattia, Davide; Gogotsi, Yury; Layton, Bradley E. <br/> <br/>Abstract: We report fluctuations in resistivity and the manifestation of Coulomb blockade phenomena of conductive multiwalled carbon nanotubes under buckling loads. Individual nanotubes were suspended and soldered between two indium-dipped tungsten probe tips. Using the electrical connection between the probes and the nanotube, electrical measurements were taken with the tube straight (unstrained) and bent (strained). Typical resistances were in the 10 GΩ range with resistivities in the 15 to 30 Ω−m range within the Coulomb blockade region of -1.0 to -0.4 V. Coulomb blockade, or electron tunneling events, appeared to occur at one of the contact points. This effect was diminished or lost once the carbon weld was broken. Sun, 22 Apr 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2602 Title: Mechanism of blood coagulation by nonthermal atmospheric pressure dielectric barrier discharge plasma <br/> <br/>Authors: Kalghatgi, Sameer U.; Fridman, Gregory; Cooper, Moogega; Nagaraj, Gayathri; Peddinghaus, Marie; Balasubramanian, Manjula; Vasilets, Victor N.; Gutsol, Alexander F.; Fridman, Alexander A.; Friedman, Gary <br/> <br/>Abstract: Mechanisms of blood coagulation by direct contact of nonthermal atmospheric pressure dielectric barrier discharge (DBD) plasma are investigated. This paper shows that no significant changes occur in the pH or Ca2+ concentration of blood during discharge treatment. Thermal effects and electric field effects are also shown to be negligible. Investigating the hypothesis that the discharge treatment acts directly on blood protein factors involved in coagulation, we demonstrate aggregation of fibrinogen, an important coagulation factor, with no effect on albumin. We conclude that direct DBD treatment triggers selective natural mechanisms of blood coagulation. Fri, 28 Sep 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2586 Title: Rapid inactivation of airborne bacteria using atmospheric pressure dielectric barrier grating discharge <br/> <br/>Authors: Gallagher Jr., Michael J.; Vaze, Nachiket; Gangoli, Shailesh Pradeep; Vasilets, Victor N.; Gutsol, Alexander F.; Milovanova, Tatyana N.; Anandan, Shivanthi; Murasko, Donna M.; Fridman, Alexander A. <br/> <br/>Abstract: Dielectric barrier discharge plasma has been known to inactivate many different microorganisms on surfaces when treatment times are on the order of seconds or minutes in duration. In this paper, a unique plasma air cleaning facility was created which combines a dielectric barrier grating discharge (DBGD) with a filterless laboratory-scale ventilation system and is used to treat concentrated bacterial bioaerosol in a moving air stream at air flow rates of 25 L/s. Results indicate that plasma treatment times on the order of milliseconds corresponding to one pass through the DBGD device can achieve 1.5-log reduction in culturable E. coli immediately after contact with plasma and 5-log reduction totally following in the minutes after the plasma treatment. A numerical characterization study was performed to help predict and understand the mechanism of bacteria inactivation in the DBD plasma from a variety of plasma factors. Fri, 28 Sep 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2584 Title: Spatially resolved temperature measurements of atmospheric-pressure normal glow microplasmas in air <br/> <br/>Authors: Staack, David; Farouk, Bakhtier; Gutsol, Alexander F.; Fridman, Alexander A. <br/> <br/>Abstract: The rotational and vibrational temperatures of dc normal glow air discharges were measured by comparing modeled optical emission spectra of the N2 second positive system with spectroscopic measurements from the discharges. By using an imaging spectrometer and optical assembly, the temperature measurements were spatially resolved to about 6 μm. Results are presented for a 3.8-mA discharge at an electrode spacing of 400 μm. Rotational temperatures are highest in the near-cathode region around 1500 K and decrease toward the anode to about 1100 K. Throughout the discharge, higher rotational temperatures correspond with lower vibrational temperatures. The maximum vibrational temperature measured is around 5000 K. Emission from the N+ 2 first negative system was also measured and is only intense in the negative glow (NG) region. The temperature near the anode is sensitive to the anode material. Gold, stainless steel, and tungsten electrodes were studied. Oxidizing anode materials can create a bright and hot anode spot several hundred Kelvin warmer than for nonreacting anode materials. In addition, comparisons between spatially resolved and previously studied emission-averaged temperatures indicate that the emissionaveraged temperatures correspond to those of the NG regions. Fri, 28 Sep 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2576 Title: Variable structure design of a fault tolerant control system for induction motors <br/> <br/>Authors: Dongmo, Jean-Etienne; Kwatny, Harry G.; Nwankpa, Chikaodinaka Okechi Dike; Bajpai, Gaurav Ratnesh; Teolis, Carole <br/> <br/>Abstract: In this paper we describe a method for designing switching controls and analyzing achievable performance for motor drives. The method is proposed as a means for constructing a family of controls to achieve acceptable operation of motors under a variety of fault conditions. Sun, 20 May 2007 22:58:59 GMT