552 research outputs found

    Set up of a light sheet fluorescence microscope for cellular studies

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    Light-sheet fluorescence microscopy (LSFM) has been present in cell biology laboratories for quite some time, mainly as custom-made systems, with imaging applications ranging from single cells (in the μm scale) to small organisms (mm). Such microscopes distinguish themselves for having very low phototoxicity levels and high spatial and temporal resolution, properties that render it ideal for 3D characterization of cell motility in migration and traction force studies. Cellular motion has proven to be essential in biological processes such as tumor metastasis and tissue development. Experimental setups make extensive use of microdevices (bioMEMS) that are providing higher degrees of empirical complexity. The following report details the process of setting-up a functional LSFM device for imaging cell motion in microfluidic devices. It begins with a brief summary of fluorescence imaging and current techniques, important to understand why single-plane illumination microscopy (SPIM) was chosen among other light-sheet methods. Then, the whole SPIM set-up process is described, containing explanations about the physical and material properties of the hardware used, the intricacies of the control system, and important procedures. These procedures include: calibration of the microscope, sample preparation in microdevices, and image acquisition from the software provided. Real fluorescence images acquired serve as evidence of the functionality of the instrument. The current limitations are highlighted, and pointers on how to improve or enhance the device are given. The report contains many diagrams, tables and pictures to aid in the understanding of important concepts. In the Annex, a comprehensive table listing the project costs by category is attached. This table includes links to the manufacturers and providers. The aim of this writing is to serve as an exhaustive guideline and be of reproducible use for researchers aiming to build SPIM systems for similar applications.Ingeniería Biomédic

    Simulation analysis of turbine blade in 3D printing aquarium

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    3D printing of the flexibility is the most admirable place, no matter when or where, as long as the machine can make the abstract design of finished products or difficult to process the finished product printed out as a sample. And in the product design, through the 3D print out the entity, to more specific observation of the advantages and disadvantages of finished products, which shorten the time of many creative research and development, but also relatively reduce the defective factors. As in recent years, 3D printing technology is progressing, material adhesion, precision and parts of the degree of cooperation has increased, coupled with many parts taking into account the cost, production and other issues, and then let a lot of light load small parts or special parts choose to use 3D to print the finished product to replace. This study focuses on the plastic turbine blades that drive water in the aquarium, but the 3D printing is done by stacking. However, the general stress analysis software can set the material to analyze the deformation results of the force, nor the 3D to analyze the software. Therefore, this study first analyzes the deformation of turbine blade by software, and then verifies the situation of 3D printing turbine blade, and then compares the actual results of software analysis and 3D printing. The results can provide the future of 3D product consider the strength factor. The study found that the spiral blade design allows the force points to be dispersed to avoid hard focus

    Solidification at the high and low rate extreme

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    The microstructure selection at both high and low growth rates is studied. For the high rate extreme, melt spinning of a Fe-Si-B alloy is employed. The microstructural variations with changing wheel speed and factors affecting these variations are examined through various characterization techniques. Particular attention was given for the influence of melt pool behavior on the competition between nucleation of crystalline solidification products and glass formation. It is found that there exists a window of wheel speeds which give rise to a stable melt-pool and production of amorphous ribbons. The surface-controlled melt-pool oscillation is found as the dominant factor governing the onset of unsteady thermal conditions accompanied by varying amounts of crystalline nucleation observed near the lower wheel speed limit. For the upper wheel speed limit, a criterion based on mass-balance and momentum transfer is developed for predicting the window of wheel speeds for obtaining uniform and fully amorphous ribbons. For the low rate extreme, solidification and morphological selection of the faceted silicon phase is investigated in a near eutectic Al-Si system by utilizing a Bridgman type directional solidification unit. Particularly, the role of certain defect mechanisms namely, twinning, in the selection of microstructure and growth crystallography is investigated. At the imposed growth rates of 0.5 and 1 micron/s and temperature gradient of 7.5 K/mm, a unique silicon morphology consisting of 8-pointed stars is observed to grow with \u3c001\u3e texture within continuous domains across the sample. The growth crystallography of this unique silicon structure is characterized and it is found that substantial amount of 210 type twinning exists within the central core of this star-shaped morphology. It is found that the twinning phenomenon at the core is an essential feature for branching, morphological selection and adjustment of spacing between the star-like silicon features. These mechanisms and the associated growth characteristics are examined in detail

    A Guide to Additive Manufacturing

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    This open access book gives both a theoretical and practical overview of several important aspects of additive manufacturing (AM). It is written in an educative style to enable the reader to understand and apply the material. It begins with an introduction to AM technologies and the general workflow, as well as an overview of the current standards within AM. In the following chapter, a more in-depth description is given of design optimization and simulation for AM in polymers and metals, including practical guidelines for topology optimization and the use of lattice structures. Special attention is also given to the economics of AM and when the technology offers a benefit compared to conventional manufacturing processes. This is followed by a chapter with practical insights into how AM materials and processing parameters are developed for both material extrusion and powder bed fusion. The final chapter describes functionally graded AM in various materials and technologies. Throughout the book, a large number of industrial applications are described to exemplify the benefits of AM

    Solidification and Gravity VII

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    International audienc

    Additive Manufacturing Research and Applications

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    This Special Issue book covers a wide scope in the research field of 3D-printing, including: the use of 3D printing in system design; AM with binding jetting; powder manufacturing technologies in 3D printing; fatigue performance of additively manufactured metals, such as the Ti-6Al-4V alloy; 3D-printing methods with metallic powder and a laser-based 3D printer; 3D-printed custom-made implants; laser-directed energy deposition (LDED) process of TiC-TMC coatings; Wire Arc Additive Manufacturing; cranial implant fabrication without supports in electron beam melting (EBM) additive manufacturing; the influence of material properties and characteristics in laser powder bed fusion; Design For Additive Manufacturing (DFAM); porosity evaluation of additively manufactured parts; fabrication of coatings by laser additive manufacturing; laser powder bed fusion additive manufacturing; plasma metal deposition (PMD); as-metal-arc (GMA) additive manufacturing process; and spreading process maps for powder-bed additive manufacturing derived from physics model-based machine learning

    A Guide to Additive Manufacturing

    Get PDF
    This open access book gives both a theoretical and practical overview of several important aspects of additive manufacturing (AM). It is written in an educative style to enable the reader to understand and apply the material. It begins with an introduction to AM technologies and the general workflow, as well as an overview of the current standards within AM. In the following chapter, a more in-depth description is given of design optimization and simulation for AM in polymers and metals, including practical guidelines for topology optimization and the use of lattice structures. Special attention is also given to the economics of AM and when the technology offers a benefit compared to conventional manufacturing processes. This is followed by a chapter with practical insights into how AM materials and processing parameters are developed for both material extrusion and powder bed fusion. The final chapter describes functionally graded AM in various materials and technologies. Throughout the book, a large number of industrial applications are described to exemplify the benefits of AM

    Cellular Metals: Fabrication, Properties and Applications

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    Cellular solids and porous metals have become some of the most promising lightweight multifunctional materials due to their superior combination of advanced properties mainly derived from their base material and cellular structure. They are used in a wide range of commercial, biomedical, industrial, and military applications. In contrast to other cellular materials, cellular metals are non-flammable, recyclable, extremely tough, and chemically stable and are excellent energy absorbers. The manuscripts of this Special Issue provide a representative insight into the recent developments in this field, covering topics related to manufacturing, characterization, properties, specific challenges in transportation, and the description of structural features. For example, a presented strategy for the strengthening of Al-alloy foams is the addition of alloying elements (e.g., magnesium) into the metal bulk matrix to promote the formation of intermetallics (e.g., precipitation hardening). The incorporation of micro-sized and nano-sized reinforcement elements (e.g., carbon nanotubes and graphene oxide) into the metal bulk matrix to enhance the performance of the ductile metal is presented. New bioinspired cellular materials, such as nanocomposite foams, lattice materials, and hybrid foams and structures are also discussed (e.g., filled hollow structures, metal-polymer hybrid cellular structures)

    Optical Confinement in the Nanocoax:

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    Thesis advisor: Michael J. NaughtonThe nanoscale coaxial cable (nanocoax) has demonstrated sub-diffraction-limited optical confinement in the visible and the near infrared, with the theoretical potential for confinement to scales arbitrarily smaller than the free space wavelength. In the first part of this thesis, I define in clear terms what the diffraction limit is. The conventional resolution formulae used by many are generally only valid in the paraxial limit. I performed a parametric numerical study, employing techniques of Fourier optics, to resolve precisely what that limit should be for nonparaxial (i.e. wide angle) focusing of scalar spherical waves. I also present some novel analytical formulae born out of Debye’s approximation which explain the trends found in the numeric study. These new functional forms remain accurate under wide angle focusing and could materially improve the performance, for example, in high intensity focused ultrasound surgery by further concentrating the power distributed within the point spread function to suppress the side lobes. I also comment of some possible connections to the focusing of electromagnetic waves. In the second part of this thesis I report on a novel fabrication process which yields optically addressable, sub-micron scale, and high aspect ratio metal-insulator-metal nanocoaxes made by atomic layer deposition of Pt and Al2O3. I discuss the observation of optical transmission via the fundamental, TEM-like mode by excitation with a radially polarized optical vortex beam. Also, Laguerre-Gauss beams are shown to overlap well with cylindrical waveguide modes in the nanocoax. My experimental results are based on interrogation with a polarimetric imager and a near-field scanning optical microscope. Various optical apparatus I built during my studies are also reviewed. Numerical simulations were used with uniaxial symmetry to explore 3D adiabatic taper geometries much larger than the wavelength. Finally, I draw some conclusions by assessing the optical performance of the fabricated nanocoaxial structures, and by giving some insights into future directions of investigation.Thesis (PhD) — Boston College, 2019.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Physics
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