13,610 research outputs found

    Human engineering design criteria handbook for lunar scientific equipment

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    Human engineering design criteria handbook for lunar scientific equipmen

    Measurement technology: A compilation

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    Technical information is presented on measurement techniques and instruments, measurement applications for inspection activities, measurement sensors, and data conversion methods. Photographs or diagrams are included for each instrument or method described, and where applicable, patent information is given

    Recent trends, technical concepts and components of computer-assisted orthopedic surgery systems: A comprehensive review

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    Computer-assisted orthopedic surgery (CAOS) systems have become one of the most important and challenging types of system in clinical orthopedics, as they enable precise treatment of musculoskeletal diseases, employing modern clinical navigation systems and surgical tools. This paper brings a comprehensive review of recent trends and possibilities of CAOS systems. There are three types of the surgical planning systems, including: systems based on the volumetric images (computer tomography (CT), magnetic resonance imaging (MRI) or ultrasound images), further systems utilize either 2D or 3D fluoroscopic images, and the last one utilizes the kinetic information about the joints and morphological information about the target bones. This complex review is focused on three fundamental aspects of CAOS systems: their essential components, types of CAOS systems, and mechanical tools used in CAOS systems. In this review, we also outline the possibilities for using ultrasound computer-assisted orthopedic surgery (UCAOS) systems as an alternative to conventionally used CAOS systems.Web of Science1923art. no. 519

    Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

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    INE/AUTC 10.0

    Medical image computing and computer-aided medical interventions applied to soft tissues. Work in progress in urology

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    Until recently, Computer-Aided Medical Interventions (CAMI) and Medical Robotics have focused on rigid and non deformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g. HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

    Effects of Solder Paste Volume on PCBA Assembly Yield and Reliability

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    Solder paste printing is the most common method for attaching surface mount devices to printed circuit boards and it has been reported that a majority of all assembly defects occur during the stencil printing process. It is also recognized that the solder paste printing process is wholly responsible for the solder joint formation of leadless package technologies such as Land Grid Array (LGA) and Quad-Flat No-Lead (QFN) components and therefore is a determining factor in the long-term reliability of said devices. The goal of this experiment is to determine the acceptable lower limit for solder paste volume deposit tolerances during stencil printing process to ensure both good assembly yield and reliability expectations. Stencils with modified aperture dimensions at particular locations for LGA and QFN package footprints were designed in order to vary the solder paste volume deposited during the stencil printing process. Solder paste volumes were measured using Solder Paste Inspection (SPI) system. Low volume solder paste deposits were generated using the modified stencil designs to evaluate assemble yield. Accelerated Thermal Cycling (ATC) was used to determine the reliability of the solder joints. For the LGAs, solder joints formed with higher paste volume survived longer in ATC compared to lower volume joints. Low solder paste volume deposits did not affect BGA devices in ATC. Transfer efficiency numbers for both good assembly yield and good reliability are reported for LGA, QFN and BGA devices. This research provides valuable data because, very little data is available on solder paste volume tolerance limits in terms of assembly yield and reliability. Manufacturers often use ±50% of stencil aperture volume with no evidence of its effectiveness in determining yield and reliability of the solder joints

    Design and Implementation of an Automated Pick and Place System for Johanson Technology, Inc.

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    Johanson Technology, a capacitor and microelectronic part manufacturer, located in Camarillo, CA has forecasted a 50% increase in demand for single layer capacitors for the year 2011. Johanson chose to hire an intern to design and implement a robotic pick and place system to meet this demand. A complete automated system composed of a Stäubli RS20 robotic arm, CS8C-M Controller, and Electrosort Bowl Feeder needed to be integrated into an environment where no system currently existed. A bill of materials and parts list indicated that the entire system would be a fixed cost of 50,104.Thisprovedtobethesuperiorchoiceoverthealternativesofhiringanoutsideconsultanttodesignthesystemfor50,104. This proved to be the superior choice over the alternatives of hiring an outside consultant to design the system for 115,051 or hiring an additional employee to hand pick and place the parts for nearly $24,000 annually. Programs were written in VAL3, Stäubli’s own programming language, for the RS20 to pick and place parts in a grid formation onto Waffle, Gel, and Ring Packs. A custom tool composed of manufactured and purchased parts was made at Johanson Technology and held by the RS20 arm to handle the single layer capacitors. Performance of the system’s placement accuracy was analyzed by measuring correct placements on Waffle, Gel, and Ring Packs. Waffle Packs received a placement accuracy of 99.21%, missing around 10-20 parts out of 2,400. Gel Packs received 99.71% accuracy, and Ring Packs failed to place parts consistently within their 2-3⁰ rotation tolerance so their accuracy of placement could not be measured. The robotic pick and place system places single layer capacitors into Waffle, Gel, and Ring Packs at two to three times the speed of a human operator. At this rate, Johanson Technology will be able to meet their demand
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