In-situ monitoring for CVD processes

Aiming towards process control of industrial high yield/high volume CVD reactors, the potential of optical sensors as a monitoring tool has been explored. The sensors selected are based on both Fourier transform infrared spectroscopy (FTIR) and tunable diode laser spectroscopy (NIR-DLS). The former has the advantage of wide spectral capability, and well established databases. NIR-DLS spectroscopy has potentially high sensitivity, laser spatial resolution, and the benefits of comparatively easier integration capabilities-including optical fibre compatibility. The proposed technical approach for process control is characterised by a 'chemistry based' feedback system with in-situ optical data as input information. The selected optical sensors continuously analyze the gas phase near the surface of the growing layer. The spectroscopic data has been correlated with process performance and layer properties which, in turn establish data basis for process control. The new process control approach is currently being verified on different industrialised CVD coaters. One of the selected applications deals with the deposition of SnO2 layers on glass based on the oxidation of (CH3)2SnCl2, which is used in high volume production for low-E glazing

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Application of stereoscopic PIV for hemodynamic studies of life-sized carotid artery models under pulsatile flow condition

One of the major causes of ischemic stroke is embolism of thrombi (i.e. blood clots) that are formed at the site of the atherosclerotic plaque in the carotid artery bifurcation. Certain hemodynamic factors, such as flow disturbances, shear stress forces, and recirculation are linked to thrombosis by enhancing and facilitating platelet activation and aggregation [1, 2]. Any alterations of the local flow patterns that can, in turn, induce altered hemodynamic factors can impact the level of thrombotic activity. Previous clinical studies have shown the association of certain geometrical features of the plaque, namely severity of stenosis (i.e. narrowing), plaque eccentricity (symmetry), and plaque ulceration (irregular surface) to the frequency of cerebrovascular events [3, 4]. As a gold-standard experimental technique, particle image velocimetry (PIV) can provide detailed analysis of spatially and temporally evolving flows. This technique has extensively been applied to hemodynamic studies, primarily to investigate the potential of thrombosis in mechanical heart valves (ref). To date, only three PIV studies (excluding echo PIV studies) have been reported in carotid artery models; Bale-Glickman et al. [5] applied planar PIV to two patientspecific stenosed carotid artery models, Vetel et al. [6] studied flow in a patient-specific model of a healthy carotid artery using stereo PIV, and Buchmann et al. [7] studied a healthy carotid artery model and compared results using tomographic and stereoscopic PIV. All studies were conducted assuming steady inlet flow; although they provide a baseline understanding of flow patterns, pulsatile flow conditions strongly impact the flow dynamics, introducing flow instabilities and high temporal gradients. We have developed a flow-measurement system applying stereoscopic PIV in a family of life-sized carotid artery models, representing a range of disease progression, under physiologically realistic flow conditions in order to characterize stenosed flow features and investigate the impact of the geometrical features of the plaque on downstream flow patterns. A detailed description of the experimental design features and challenges are described, along with sample results. To demonstrate the capability of this system, flow features extracted from a 70% concentrically stenosed model are presented

Overview of the MFTF electrical systems

The Mirror Fusion Test Facility, scheduled for completion in October 1981, will contain a complex, state-of-the-art array of electrical and electronics equipment valued at over 60 M$. Three injector systems will be employed to initiate and sustain the MFTF deuterium plasma. A plasma streaming system and a startup neutron beam system will be used to establish a target plasma. A sustaining neutral beam system will be used to fuel and sustain the MFTF plasma for 0.5 s. Additional power supply systems required on MFTF include two magnet power supplies with quench protection circuitry for powering the superconducting YIN/YANG magnet pair and eight 10 KHz power supplies for powering the Ti gettering system. Due to the complexity, physical size, and multiple systems of MFTF, a distributed, hierarchial, computer control and instrumentation system will be used. Color graphic, touch-panel, control consoles will provide the man-machine interface. The MFTF will have the capability of conducting an experiment every five minutes