Measurements with multi-point microprobes: Effect of suspended solids on the hydrodynamics of bubble columns for application in chemical and biotechnological processes

Many experimental studies reveal that suspended solids considerably alter the coalescence behaviour and hydrodynamic functions of wo-phase flow. But no systematic efforts have yet been undertaken to separate the effects of different particle properties on local gas hold-up, bubble size and interfacial area gas/liquid. The aim of this paper is to present the local values of these parameters in three-phase fluidized beds of different solids, using miniaturized optical fiber and conductivity needle probes. It is shown that particle concentration, size and, in particular, density are decisive for the change in coalescence behaviour. Ranges of normal (?_S > ?_L) and inverse fluidization (?_S < ?_L) must be distinguished and the flow regime also exerts a strong influence on the interactions between the dispersed phases, the transition point itself being a function of particle properties can be observed, This effect is evaluated for different column diameters, between 0.1 and 0.3 m.     

Determination of deuterium in dead-sea water by nuclear methods

By using the D(d, p)³H nuclear reaction combined with the Rutherford-backscattering method, the amount of D₂O in relation to H₂O in water from the Dead Sea is measured. The amount of deuterium in the samples is determined from the integrated yield of the D(d, p)³H reaction in relation to the ¹⁶O(d, p₀)¹⁷O or ¹⁶O(d, p₁)¹⁷O reaction. For the low deuteron energies used (E 0.63 MeV), the differential cross section of the ¹⁶O(d, p₀)¹⁷O reaction was determined experimentally. No significant change of deuterium concentration in Dead-Sea water down to a depth of 36 m could be detected.     

Fabrication of discontinuous surface patterns within microfluidic channels using photodefinable vapor-based polymer coatings

In this report, we introduce a surface modification method for the fabrication of discontinuous surface patterns within microfluidic systems. The method is based on chemical vapor deposition (CVD) of a photodefinable coating, poly(4-benzoyl-p-xylylene-co-p-xylylene), onto the luminal surface of a microfluidic device followed by a photopatterning step to initiate spatially controlled surface binding. During photopatterning, light-reactive groups of the CVD polymer spontaneously react with molecules adjunct to the surface, such as poly(ethylene oxide). We demonstrate the potential of these reactive polymers for surface modification by preventing nonspecific protein adsorption on different substrates including silicon and poly(dimethylsiloxane) as measured by fluorescence microscopy. More importantly, three-dimensional patterns have successfully been created within polymer-based microfluidic channels, establishing spatially controlled, bioinert surfaces. The herein reported surface modification method addresses a critical challenge with respect to surface engineering of microfluidic devices, namely, the fabrication of discontinuous patterns within microchannels.     

Multidimensional velocity filters for visual scene analysis in automotive driver assistance systems

Automotive scenery often contains objects that can be classified by object speed and movement direction. These features can be extracted from video data by linear n-D filters, which have already been analyzed in the past. While soundness of results was convincing, interest in those systems declined due to the reduced computational abilities of contemporary computers. Modern hardware allows realization of velocity filters, if the n-D system is carefully adapted to the analysis problem. The present paper analyzes the premises for application of velocity filters in the domain of automotive driver assistance systems, i.e. with respect to detectability of objects and implementability in a cost effective way. Especially the influence of the frame rate and the temporal violation of the sampling theorem are analyzed. Transfer functions for n-D filters working in a vision-based blind spot collision avoidance system are presented and discussed, and promising approaches for future application fields are proposed.     

High resolution fMRI of subcortical regions during visual erotic stimulation at 7 T

Object Involvement of distinct subcortical structures during sexual arousal was shown in animals and functional imaging studies gave coarse evidence for a similar organisation in humans. In contrast to previous imaging studies at lower field strengths, we tried to investigate activation in distinguishable subcortical structures at high spatial resolution during a short stimulating paradigm to further account for potential effects of attenuation or adaptation. Materials and methods Seven healthy subjects were investigated using functional magnetic resonance imaging (fMRI) on a 7 T scanner. High resolution EPI images of 1.4 × 1.4 mm² inplane resolution were acquired in a single functional session of 13.6 minutes. During the session erotic and non-erotic pictures were presented in an event-related design. Results In the unsmoothed data with preserved high spatial resolution significant effects were detected in relevant structures, including anterior caudate and mediodorsal thalamus. These effects were restricted to subcortical target structures and their anatomical boundaries. Conclusion This study demonstrates that fMRI at high fields provides an ideal tool to investigate functional anatomy of subcortical structures. Due to an increased signal-to-noise ratio, functional scans of short duration can be acquired at high resolution without the need for further spatial smoothing.     

Joint Modulations of Electromagnetic Waves and Digital Signals on a Single Metasurface Platform to Reach Programmable Wireless Communications

In current wireless communication and electronic systems,digital signals and electromagnetic(EM)radi-ation are processed by different modules.Here,we propose a ...     

Poly(2-oxazoline)s with a 2,2′-Iminodiacetate End Group Inhibit and Stabilize Laccase

Poly(2-oxazoline)s (POxs) with 2,2′-iminodiacetate (IDA) end groups were investigated as inhibitors for laccase. The polymers with the IDA end groups are reversible, competitive inhibitors for this enzyme. The IC₅₀ values were found to be in a range of 1–3 mm . Compared with IDA alone, the activity was increased by a factor of more than 30; thus indicating that attaching a polymer chain to an inhibitor can already improve the activity of the former. The enzyme activity drops to practically zero upon increasing the concentration of the most active telechelic inhibitor, IDA-PEtOx₃₀-IDA (PEtOx: poly(2-ethyl-2-oxazoline)), from 5 to 8 mm . This unusual behavior was investigated by means of dynamic light scattering, which showed specific aggregation above 5 mm . Furthermore, the laccase could be stabilized in the presence of POx-IDA, upon addition at a concentration of 20 mm and higher. Whereas laccase becomes completely inactive at room temperature after one week, the stabilized laccase is fully active for at least a month in aqueous solution.     

Physical Representation Learning and Parameter Identification from Video Using Differentiable Physics

International Journal of Computer Vision - Representation learning for video is increasingly gaining attention in the field of computer vision. For instance, video prediction models enable activity...     

Laterally vibrating MEMS resonant vacuum sensor based on cavity-SOI process for evaluation of wide range of sealed cavity pressure

Microsystem Technologies - This paper reports a laterally vibrating MEMS resonant vacuum sensor which senses ambient pressure based on the squeeze-film damping effect. The single-anchored...