http://idea.library.drexel.edu/handle/1860/722 http://idea.library.drexel.edu/retrieve/4832 http://idea.library.drexel.edu/handle/1860/722 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/1860/2751 Title: Sliding wear properties of HVOF thermally sprayed nylon-11 and nylon-11/ceramic composites on steel <br/> <br/>Authors: Jackson, L.; Ivosevic, M.; Knight, Richard; Cairncross, R. A. <br/> <br/>Abstract: Polymer and polymer/ceramic composite coatings were produced by ball-milling 60 μm Nylon- 11 together with nominal 10 vol.% of nano and multi-scale ceramic reinforcements and HVOF spraying these composite feedstocks onto steel substrates to produce semi-crystalline micron and nano-scale reinforced coatings polymer matrix composites. Room temperature dry sliding wear performance of pure Nylon-11, Nylon-11 reinforced with 7 nm silica, and multi-scale Nylon- 11/silica composite coatings incorporating 7-40 nm and 10 μm ceramic particles was characterized using a pin-on-disk tribometer. Coefficient of friction and wear rate were determined as a function of applied load and coating composition. Surface profilometry and scanning electron microscopy were used to characterize and analyze the coatings and wear scars. The pure Nylon-11 coating experienced less wear than the composites due to the occurrence of two additional wear mechanisms: abrasive and fatigue wear. Sun, 29 Oct 2006 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/1860/2748 Title: Validation of high gradient magnetic field based drug delivery to magnetizable implants under flow <br/> <br/>Authors: Forbes, Zachary G.; Yellen, Benjamin B.; Halverson, Derek S.; Fridman, Gregory; Barbee, Kenneth A.; Friedman, Gary <br/> <br/>Abstract: The drug-eluting stent’s increasingly frequent occurrence late stage thrombosis have created a need for new strategies for intervention in coronary artery disease. This paper demonstrates further development of our minimally invasive, targeted drug delivery system that uses induced magnetism to administer repeatable and patient specific dosages of therapeutic agents to specific sites in the human body. Our first aim is the use of magnetizable stents for the prevention and treatment of coronary restenosis; however, future applications include the targeting of tumors, vascular defects, and other localized pathologies. Future doses can be administered to the same site by intravenous injection. This implant-based drug delivery system functions by placement of a weakly magnetizable stent or implant at precise locations in the cardiovascular system, followed by the delivery of magnetically susceptible drug carriers. The stents are capable of applying high local magnetic field gradients within the body, while only exposing the body to a modest external field. The local gradients created within the blood vessel create the forces needed to attract and hold drug-containing magnetic nanoparticles at the implant site. Once these particles are captured, they are capable of delivering therapeutic agents such as antineoplastics, radioactivity, or biological cells. Tue, 29 Jan 2008 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/1860/2732 Title: Effect of heating rate on recrystallization of twin roll cast aluminum <br/> <br/>Authors: Sun, Naiyu; Patterson, Burton R.; Suni, Jaakko P.; Doherty, Roger D.; Weiland, Hasso; Kadolkar, Puja; Blue, Craig A.; Thompson, Gregory B. <br/> <br/>Abstract: The effect of heating rate on precipitation and recrystallization behavior in twin roll cast (TRC) AA3105 has been investigated by three different means: conventional air furnace, controlled infrared, and lead bath heating. Experimental results showed that as-recrystallized grain size decreased and became more equiaxed as the annealing heating rate increased. These results were explained via time-temperature-transformation (TTT) curves for both dispersoid precipitation and recrystallization. With the faster heating rate, recrystallization could occur before precipitation of Mn present in the unhomogenized TRC samples. At a heating rate of 50 degree C/s the material underwent grain growth after recrystallization at 500 degree C. No sign of grain growth was observed in materials annealed with lower heating rates, 3 degrees C/s, 0.5 degree C/s, and 0.01 degree C/s due to greater dispersoid precipitation. Sat, 29 Dec 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2722 Title: Kinking nonlinear elastic solids, nanoindentations, and geology <br/> <br/>Authors: Barsoum, Michel W.; Murugaiah, A.; Kalidindi, Surya R.; Zhen, T. <br/> <br/>Abstract: The physical mechanism responsible for nonlinear elastic, hysteretic, and discrete memory response of nonlinear mesoscopic elastic solids has to date not been identified.We show, by nanoindenting mica single crystals, that this response is most likely due to the formation of dissipative and fully reversible, dislocation-based kink bands. We further claim that solids with high c=a ratios, which per force are plastically anisotropic, should deform by kinking, provided they do not twin. These kinking nonlinear elastic solids include layered ternary carbides, nitrides, oxides, and semiconductors, graphite, and the layered phases, such as mica, present in nonlinear mesoscopic elastic solids. Thu, 24 Jun 2004 22:58:59 GMT