1,420 research outputs found

    Implementation of control point form of algebraic grid-generation technique

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    The control point form (CPF) provides explicit control of physical grid shape and grid spacing through the movement of the control points. The control point array, called a control net, is a space grid type arrangement of locations in physical space with an index for each direction. As an algebraic method CPF is efficient and works well with interactive computer graphics. A family of menu-driven, interactive grid-generation computer codes (TURBO) is being developed by using CPF. Key features of TurboI (a TURBO member) are discussed and typical results are presented. TurboI runs on any IRIS 4D series workstation

    Multiship Crane Sequencing with Yard Congestion Constraints

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    Crane sequencing in container terminals determines the order of ship discharging and loading jobs that quay cranes (QCs) perform, so that the duration of a vessel's stay is minimized. The ship's load profile, berthing time, number of available bays, and QCs are considered. More important, clearance and yard congestion constraints need to be included, which, respectively, ensure that a minimum distance between adjacent QCs is observed and yard storage blocks are not overly accessed at any point in time. In sequencing for a single ship, a mixed-integer programming (MIP) model is proposed, and a heuristic approach based on the model is developed that produces good solutions. The model is then reformulated as a generalized set covering problem and solved exactly by branch and price (B&P). For multiship sequencing, the yard congestion constraints are relaxed in the spirit of Lagrangian relaxation, so that the problem decomposes by vessel into smaller subproblems solved by B&P. An efficient primal heuristic is also designed. Computational experiments reveal that large-scale problems can be solved in a reasonable computational time

    Method for fabricating vertically-offset interdigitated comb actuator device

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    The present invention relates to systems and methods for fabricating microscanners. The fabrication processes employed pursuant to some embodiments are compatible with well known CMOS fabrication techniques, allowing devices for control, monitoring and/or sensing to be integrated onto a single chip. Both one- and two-dimensional microscanners are described. Applications including optical laser surgery, maskless photolithography, portable displays and large scale displays are described

    Nanoarray-Enhanced Micromechanical Pressure Sensor with Remote Optical Readout

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    We demonstrate a compact implantable intraocular pressure (IOP) sensor with remote optical readout for glaucoma research and patient management. Using non-invasive white light, we excite the sensor’s pressure-sensitive optomechanical cavity and detect the reflected light, whose optical signature changes as a function of IOP. The sensor has provided robust measurements of hydrostatic pressure between 10-60 mmHg with an accuracy of 0.15 mmHg

    A microscale optical implant for continuous in vivo monitoring of intraocular pressure

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    Intraocular pressure (IOP) is a key clinical parameter in glaucoma management. However, despite the potential utility of daily measurements of IOP in the context of disease management, the necessary tools are currently lacking, and IOP is typically measured only a few times a year. Here we report on a microscale implantable sensor that could provide convenient, accurate, on-demand IOP monitoring in the home environment. When excited by broadband near-infrared (NIR) light from a tungsten bulb, the sensor’s optical cavity reflects a pressure-dependent resonance signature that can be converted to IOP. NIR light is minimally absorbed by tissue and is not perceived visually. The sensor’s nanodot-enhanced cavity allows for a 3–5 cm readout distance with an average accuracy of 0.29 mm Hg over the range of 0–40 mm Hg. Sensors were mounted onto intraocular lenses or silicone haptics and secured inside the anterior chamber in New Zealand white rabbits. Implanted sensors provided continuous in vivo tracking of short-term transient IOP elevations and provided continuous measurements of IOP for up to 4.5 months
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