287 research outputs found

    Fundamentals of Vertical Density Profile Formation in Wood Composites. Part I. In-Situ Density Measurement of the Consolidation Process

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    We have designed a radiation-based system for measuring density of wood composite mats during consolidation. The system is installed on a laboratory hot-press and has been used to study consolidation of medium density fiberboard (MDF) and oriented strandboard (OSB) mats. Measuring density of the wood mat during consolidation is a key parameter for understanding subsequent product performance. The in-situ measuring system provides for density measurement at three horizontal planes in the wood mat, at positions of 25%, 50%, and 75% of the mat thickness at any time during the press cycle. The system incorporates three cesium137 sources and electronic detection equipment, collimated to move in concert with the up-acting press platen. Radiation count data taken through the mat during pressing are converted to density after pressing. Press position and time are simultaneously recorded with the count data. Moisture migration during hot-pressing resulted in significant density changes as measured by the in-press radiation-based system. Clearly established in all laboratory pressing studies is the indication that the vertical density profile of wood composite panels is formed from a combination of actions that occur both during consolidation and also after the press has reached final position; measurements recorded in the press show that mat densification continues after the press has reached final position. A description of the radiation system and data from elementary pressing examples are presented, along with experimental results of the effects of moisture migration in the mat on measured density during pressing

    Intra-regional transportation of a tugboat fouling community between the ports of recife and natal, northeast Brazil

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    Minimally invasive surgery and cancer: controversies part 1

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    Perhaps there is no more important issue in the care of surgical patients than the appropriate use of minimally invasive surgery (MIS) for patients with cancer. Important advances in surgical technique have an impact on early perioperative morbidity, length of hospital stay, pain management, and quality of life issues, as clearly proved with MIS. However, for oncology patients, historically, the most important clinical questions have been answered in the context of prospective randomized trials. Important considerations for MIS and cancer have been addressed, such as what are the important immunologic consequences of MIS versus open surgery and what is the role of laparoscopy in the staging of gastrointestinal cancers? This review article discusses many of the key controversies in the minimally invasive treatment of cancer using the pro–con debate format
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