Resonating microplates appear as ideal candidates for microcantilever-based real-time biosensing, because their low planar aspect ratio allows for effectively large Q factors, even in highly viscous fluids like water and other biological liquids. Since, a complete analytical treatment of a plate vibrating in liquid is missing; a fully numerical approach is needed for an effective design of a microcantilever-based Lab-On-Chip, as well as for its correct operation. We here report on a three-dimensional finite element model for an accurate and general solution methodology of the Fluid–Structure interaction for a plate vibrating in a transverse flexural mode within a viscous fluid environment. The model directly allows extracting vibration mode shapes, frequencies and Q factors through an eigenfrequency analysis, thus avoiding time-consuming and time-dependent simulations. A benchmark with the available analytical results (that rely on the classical beam theory) and a comparison with experimental data on a fabricated microcantilever-based Lab-On-Chip confirm the accuracy and the reliability of our numerical calculations. The here proposed model works in a very general context, without limitations about the cantilever planar geometry and material, as well as about the shape of the fluid domain. 相似文献
A series of dinuclear iron(III)I complexes supported by thioether‐triphenolate ligands have been prepared to attain highly Lewis acidic catalysts. In combination with tetrabutylammonium bromide (TBAB) they are highly active catalysts in the synthesis of cyclic organic carbonates through the coupling of carbon dioxide to epoxides with the highest initial turnover frequencies reported to date for the conversion of propylene oxide to propylene carbonate for iron‐based catalysts (5200 h−1; 120 °C, 2 MPa, 1 h). In particular, these complexes are shown to be highly selective catalysts for the coupling of carbon dioxide to internal oxiranes affording the corresponding cyclic carbonates in good yield and with retention of the initial stereochemical configuration. A density functional theory (DFT) investigation provides a rational for the relative high activity found for these Fe(III) complexes, showing the fundamental role of the hemilabile sulfur atom in the ligand skeleton to promote reactivity. Notably, in spite of the dinuclear nature of the catalyst precursor only one metal center is involved in the catalytic cycle.
PURPOSE: To study accuracy and safety, related to sensation (discomfort) and trauma, when using Goldmann applanation tonometry (GAT) on eyes wearing daily disposable soft contact lenses. METHODS: The intra-ocular pressure (IOP) of 136 normal eyes of 68 subjects was measured by Goldmann tonometer. Measurements were made in one eye with a contact lens (hilafilcon A) without anaesthetic drops and then without the contact lens using one drop of 0.4% oxybuprocaine hydrochloride. Each contact lens used was identical as to back optic zone, back vertex power. Standard Goldmann procedure only was used for the fellow eye of each subject. Subjective sensation (discomfort) responses to both procedures were studied in a subgroup (66 eyes) using a scale of discomfort, from 1 (no sensation) to 5 (highest sensation). Epithelial staining after tonometry was evaluated for this subgroup. RESULTS: No significant differences were found for the IOP with and without contact lens (t<1; p=0.63) for the IOP range studied. There was a good correlation between the two procedures (r=0.81; p<0.05). Lowest sensation was found with tonometry on the anaesthetized cornea; this condition was significantly different from other conditions (p<0.005). No difference was found among the other conditions (contact lens insertion, tonometry on contact lens and application of topical anaesthetic). Corneal epithelial staining following the standard tonometry procedure was significantly higher than following the procedure with a contact lens (p<0.00005). CONCLUSIONS: Measurement of IOP by GAT over a daily disposable soft contact lens is accurate, compared to the standard procedure and within the IOP's normal range studied here. Also using a contact lens results in less trauma whilst discomfort is similar. 相似文献
A propagation programme for peaches and nectarines has been targeted to select genotypes having taste attributes such as high sugar levels and well-balanced sugar/acid ratios. The analytical measurements of some soluble sugars and nonvolatile acids were carried out using innovative analytical procedures based on fast and selective devices which require very little or no sample pre-treatment whatsoever. These devices have found a unique application in detecting fructose, glucose and malic acid for the improvement of fruit genetics.
The present study examines relationships between the analytical measurements of sugars and non-volatile acids and the sensory attributes (sweetness and sourness) of 21 peach and nectarine cultivars. Certain chemical parameters were correlated with the organoleptic acceptance of common commercial cultivars and recently introduced high and low-acid genotypes. Multivariate statistical analyses were found to be useful in describing the variability of the chemical and sensory parameters which characterise peach quality, as they enabled the identification of sets of variables that could be used to classify peaches and nectarines into high and low-acid categories. Malic and citric acids, minor components of these fruits, were important taste attributes as they contributed to the sensory perception of sourness. 相似文献
At Karlsruhe Institute of Technology (KIT), a He-cooled divertor design for future fusion power plants has been developed. This concept is based on the use of modular cooling fingers made from tungsten and tungsten alloy, which are presently considered the most promising divertor materials to withstand the specific heat load of 10 MW/m2. Since a large number of the finger modules (n > 250,000) are needed for the whole reactor, developing a mass-oriented manufacturing method is indispensable. In this regard, an innovative manufacturing technology, Powder Injection Molding (PIM), has been adapted to W processing at KIT since a couple of years. This production method is deemed promising in view of large-scale production of tungsten parts with high near-net-shape precision, hence, offering an advantage of cost-saving process compared to conventional machining.The complete technological PIM process for tungsten materials and its application on manufacturing of real divertor components, including the design of a new PIM tool is outlined and, results of the examination of the finished product after heat-treatment are discussed. A binary tungsten powder feedstock with a solid load of 50 vol.% was developed and successfully tested in molding experiments. After design, simulation and manufacturing of a new PIM tool, real divertor parts are produced. After heat-treatment (pre-sintering and HIP) the successful finished samples showed a sintered density of approximately 99%, a hardness of 457 HV0.1, a grain size of approximately 5 μm and a microstructure without cracks and porosity. 相似文献
To carry out a variety of remote handling operations inside the ITER divertor a Water Hydraulic MANipulator (WHMAN) and its control system have been designed and developed at Tampere University of Technology. The manipulator is installed on top of Cassette Multifunctional Mover (CMM) to assist during the cassette removal and installation operations. While CMM is designed to carry heavy components such as cassettes through the service ducts relying on positioning accuracy and repeatability, WHMAN is designed to execute a mix of remote handling operations using position trajectories and master-slave telemanipulation. WHMAN is composed of eight joints: six rotational and two translational. Since a manipulator requires only six joints to acquire the desired position and orientation in operational-space, the two additional joints of WHMAN provide the redundant degrees of mobility. This paper presents how this redundancy of WHMAN can be an advantage to optimize the execution of remote handling tasks. The paper also discusses an effective way to practically exploit the redundancy. The results show that the additional degrees of freedom can be utilized to improve the dynamic behavior of the manipulator. 相似文献