Distributed communications and control network for robotic mining

The application of robotics to coal mining machines is one approach pursued to increase productivity while providing enhanced safety for the coal miner. Toward that end, a network composed of microcontrollers, computers, expert systems, real time operating systems, and a variety of program languages are being integrated that will act as the backbone for intelligent machine operation. Actual mining machines, including a few customized ones, have been given telerobotic semiautonomous capabilities by applying the described network. Control devices, intelligent sensors and computers onboard these machines are showing promise of achieving improved mining productivity and safety benefits. Current research using these machines involves navigation, multiple machine interaction, machine diagnostics, mineral detection, and graphical machine representation. Guidance sensors and systems employed include: sonar, laser rangers, gyroscopes, magnetometers, clinometers, and accelerometers. Information on the network of hardware/software and its implementation on mining machines are presented. Anticipated coal production operations using the network are discussed. A parallelism is also drawn between the direction of present day underground coal mining research to how the lunar soil (regolith) may be mined. A conceptual lunar mining operation that employs a distributed communication and control network is detailed

Exceptionally preserved fossil assemblages through geologic time and space

Geologic deposits containing fossils with remains of non-biomineralized tissues (i.e. Konservat-Lagerstätten) provide key insights into ancient organisms and ecosystems. Such deposits are not evenly distributed through geologic time or space, suggesting that global phenomena play a key role in exceptional fossil preservation. Nonetheless, establishing the influence of global phenomena requires documenting temporal and spatial trends in occurrences of exceptionally preserved fossil assemblages. To this end, we compiled and analyzed a dataset of 694 globally distributed exceptional fossil assemblages spanning the history of complex eukaryotic life (~ 610 to 3 Ma). Our analyses demonstrate that assemblages with similar ages and depositional settings commonly occur in clusters, each signifying an ancient geographic region (up to hundreds of kilometers in scale), which repeatedly developed conditions conducive to soft tissue preservation. Using a novel hierarchical clustering approach, we show that these clusters decrease in number and shift from open marine to transitional and non-marine settings across the Cambrian-Ordovician interval. Conditions conducive to exceptional preservation declined worldwide during the early Paleozoic in response to transformations of near-surface environments that promoted degradation of tissues and curbed authigenic mineralization potential. We propose a holistic explanation relating these environmental transitions to ocean oxygenation and bioturbation, which affected virtually all taphonomic pathways, in addition to changes in seawater chemistry that disproportionately affected processes of soft tissue conservation. After these transitions, exceptional preservation rarely occurred in open marine settings, excepting times of widespread oceanic anoxia, when low oxygen levels set the stage. With these patterns, non-marine cluster count is correlated with non-marine rock quantity, and generally decreases with age. This result suggests that geologic processes, which progressively destroy terrestrial rocks over time, limit sampling of non-marine deposits on a global scale. Future efforts should aim to assess the impacts of such phenomena on evolutionary and ecological patterns in the fossil record

Neuronavigation in brain tumor surgery:clinical beta-phase of the Oulu Neuronavigator System

Abstract Interactive image-guided neurosurgery for the resection of brain tumors was developed within the last 10 years at different neurosurgical centers around the world to improve the safety of the surgery and the functional outcome of the patients. Since 1987, the Oulu Neuronavigator System, consisting mainly of a mechanical arm, visualization software, an ultrasound transducer and a computer, was developed at the Neurosurgical Research Unit, University of Oulu, Finland. It was the first system to incorporate the principle of the common surgical axis for visualization, including intraoperative ultrasonography. A precommercial version of the device was jointly developed with Elekta Ab, Stockholm, Sweden, as a public project under EUREKA and introduced into a clinical beta-phase trial in 1994 as the Leksell Index System™. A total of 19 operations were performed at the Oulu University Hospital between September 1994 and September 1996 for patients harboring different kinds of intracranial tumors, especially cerebral gliomas. This thesis gives a comprehensive review of the literature from the roots of stereotaxy to the latest developments in interactive image-guided neurosurgery and discusses the advantages and disadvantages of the Leksell Index System™ with special reference to the clinical series that was performed at our institution. Future therapy strategies for the treatment of patients with cerebral gliomas, especially glioblastoma multiforme are envisioned, focusing on the further improvement of surgical interventions. The clinical trial proved that the employed neuronavigator system is versatile and safe and that there are no adverse effects, complications or surgical mortality due to the device. It enabled the surgeon to plan smaller sized and better centered skin incisions and craniotomies and to approach the target lesion with less dissection of intact brain tissue. Despite more radical removal of lesions the overall invasiveness of the operation was decreased in 63.2% of the cases, the duration of the procedure was decreased in 78.9%, and the surgeon's feeling of safety could be improved in 89.5% of the operations. Due to the use of intraoperative imaging (with ultrasound) the experience provides a unique basis for next generation neuronavigators and also for interventional MRI

A Theoretical and Experimental Study of the Electrophoretic Extraction of Ions from a Pressure Driven Flow in a Microfluidic Device

The electrophoretic extraction of ions from a hydrodynamic flow stream is investigated at an intersection between two microfluidic channels. A pressure gradient is used to drive samples through the main channel, while ions are electrophoretically extracted into the side channels. Hydrodynamic restrictors and a neutral coating are used to suppress bulk flow through the side channels. A theoretical model that assumes Poiseuille flow in the main channel and neglects molecular diffusion is used to calculate the extraction efficiency, η, as a function of the ratio, R, of the average hydrodynamic velocity to the electrophoretic velocity. The model predicts complete extraction of ions (η = 1) for R \u3c 2/3 and a monotonic decrease in η as R becomes greater than 2/3, which agrees well with the experimental results. Additionally, the model predicts that the aspect ratio of the microfluidic channel has little effect on the extraction efficiency. It is anticipated that this device can be used for on-line process monitoring, sample injection, and 2D separations for proteomics and other fields