Profile Sensor Research Articles

Analysis of the Electrolyte Convection inside the Concentration Boundary Layer during Structured Electrodeposition of Copper in High Magnetic Gradient Fields

To experimentally reveal the correlation between electrodeposited structure and electrolyte convection induced inside the concentration boundary layer, a highly inhomogeneous magnetic field, generated by a magnetized Fe-wire, has been applied to an electrochemical system. The influence of Lorentz and magnetic field gradient force to the local transport phenomena of copper ions has been studied using a novel two-component laser Doppler velocity profile sensor. With this sensor, the electrolyte convection within 500 μm of a horizontally aligned cathode is presented. The electrode-normal two-component velocity profiles below the electrodeposited structure show that electrolyte convection is induced and directed toward the rim of the Fe-wire. The measured deposited structure directly correlates to the observed boundary layer flow. As the local concentration of Cu(2+) ions is enhanced due to the induced convection, maximum deposit thicknesses can be found at the rim of the Fe-wire. Furthermore, a complex boundary layer flow structure was determined, indicating that electrolyte convection of second order is induced. Moreover, the Lorentz force-driven convection rapidly vanishes, while the electrolyte convection induced by the magnetic field gradient force is preserved much longer. The progress for research is the first direct experimental proof of the electrolyte convection inside the concentration boundary layer that correlates to the deposited structure and reveals that the magnetic field gradient force is responsible for the observed structuring effect.

Optical velocity measurements of electrolytic boundary layer flows influenced by magnetic fields

Magnetic fields are applied to electrically conducting fluids in order to influence electrochemical processes through the magnetohydrodynamic effect. Various phenomena, e.g. on electrodeposited metal layers, which can be attributed to forced convections were observed. To provide information about acting forces, the laser Doppler velocity profile sensor was applied to measure the transition layer of a Lorentz force influenced flow over a backward-facing step and the velocity boundary layer during copper deposition. With this sensor, the electrolyte convection within < 500 μm of the front of an electrode is measured with a spatial resolution down to 15 μm. The interaction of buoyancy, Lorentz and magnetic field gradient forces is studied by measuring the velocities down to 10 μm in front of the cathode. Inside the concentration boundary layer, complex electrolyte convection is induced, which varies not only in time but also in its structure, depending on the forces present and their influence over time. In inhomogeneous magnetic field configurations, the magnetic field gradient force dominates the velocity boundary layer at steady state and transports electrolyte toward regions of high magnetic gradients, where maximum deposit thicknesses are found. In this way, the measurements confirm the predicted influence of the magnetic field gradient force on the structuring of copper deposits.

Relating mobile sensor soil strength to penetrometer cone index

A horizontally operating on-the-go soil strength profile sensor (SSPS) was previously developed so that the within-field spatial variability in soil strength could be measured at five evenly spaced depths down to 50cm. Force divided by the base area of the sensing tip of the SSPS was defined as a prismatic soil strength index (PSSI, MPa), similar to the cone index (CI, MPa) of a vertically operating cone penetrometer. This study was conducted to establish theoretical and empirical relationships between PSSI and CI data to aid interpretation of PSSI data with respect to the many previous CI studies. Comparison of mathematical soil failure models for the SSPS and a conventional cone penetrometer, along with a sensitivity analysis of model parameters documented patterns of CI and PSSI in different soil and operating conditions. Patterns for both the soil strength indices were: (1) linear as a function of unit weight of soil, cohesion, adhesion, and operating depth, (2) exponential as a function of internal friction and soil-tool friction angles, and (3) quadratic as a function of operating speed. When a single model parameter was varied, the simulated CI and PSSI data showed highly significant linear relationships. Field data showed that, in general, both CI and PSSI were greater with higher bulk density, lower apparent soil electrical conductivity (ECa, where lower values indicate coarser texture), and lower gravimetric soil water content. Relationships between soil strength indices and the other measured soil variables were different when the data were divided into sub-groups by operating depth and ECa range. In models estimating CI, the effects of PSSI and its interaction with other variables were relatively clear at 30- and 40-cm depths. CI prediction models with the highest coefficients of determination were also found at these depths. Across entire fields, including operating depth in the regression model decreased RMSE values slightly from 0.35 to 0.32MPa and from 0.53 to 0.51MPa for the two test sites. These results would be useful to understand different approaches to soil strength measurement and to relate data obtained with the SSPS to the extensive research literature where CI has been used to quantify soil strength and manage the soil for better plant growth.

Application of Propagation Modeling to Verify and Discriminate Ground-Truth Infrasound Signals at Regional Distances

An infrasound field campaign was performed in 2011/2012 utilizing single infrasound sensors along the great circle path between a known ground-truth source (Ariane 5 engine test facility, Lampoldshausen, Germany) and a regional receiver (German infrasound array IS26, Bavarian Forest) covering a distance of rough 320 km in total. The gathered recordings provide new insights in the infrasonic wave propagation at regional and near-source distances by comparing measured signals with modeling results within this study. Ray-tracing and parabolic equation approaches are utilized to model infrasound propagation from the ground-truth source to the line profile sensors and explain the obtained detections and non-detections. Modeling and observation results are compared by estimating their amplitude, quantifying amplitude deviations and also considering observed and calculated travel times and celerities. Modeling results show a significant influence of small-scale atmospheric variations in effective sound speed profiles on the propagation pattern, which results in varying tropospheric and stratospheric ducting behavior. A large number of gravity wave profiles are tested to investigate the influences of atmospheric dynamics on the infrasound wave field and improve the modeling results. The modeling is furthermore applied to a case of two potential, contemporaneous and closely spaced infrasound sources. Propagation modeling is used here to resolve the source ambiguity between a ground-based and a higher altitude source giving a strong preference to the latter with respect to the observed infrasonic signatures. The good agreement between modeling and observation results within this study successfully shows the benefit of applying infrasound propagation modeling to the validation of infrasound measurements, verification of ducting behavior and discrimination of infrasound sources.

Determination of the phase-resolved body force produced by a dielectric barrier discharge plasma actuator

Dielectric barrier discharge (DBD) plasma actuators are a promissing tool for active flow control applications. In order to determine the time-resolved body force induced by a DBD plasma actuator, which was driven by a 9.5 kHz sinusoidal signal, the flow has to be captured with a high spatial and temporal resolution. For this purpose we applied a laser Doppler velocity profile sensor for the measurements of the two-component velocity field and Lagrangian acceleration. A temporal and spatial resolution of 7.3 µs and 40 µm was achieved. We present the time-resolved local flow behaviours induced by the DBD actuator. Based on these measurement data the time-resolved body force generated by the plasma actuator was derived. Experiments revealed a defined dependence of the force direction on the phase angle of the ac operating voltage. This result is a contribution to the controversy on the temporal behaviour of the body force of plasma actuators.

Advancing Profiling Sensors with a Wireless Approach

The notion of a profiling sensor was first realized by a Near-Infrared (N-IR) retro-reflective prototype consisting of a vertical column of wired sparse detectors. This paper extends that prior work and presents a wireless version of a profiling sensor as a collection of sensor nodes. The sensor incorporates wireless sensing elements, a distributed data collection and aggregation scheme, and an enhanced classification technique. In this novel approach, a base station pre-processes the data collected from the sensor nodes and performs data re-alignment. A back-propagation neural network was also developed for the wireless version of the N-IR profiling sensor that classifies objects into the broad categories of human, animal or vehicle with an accuracy of approximately 94%. These enhancements improve deployment options as compared with the first generation of wired profiling sensors, possibly increasing the application scenarios for such sensors, including intelligent fence applications.

Force sensitive carbon nanotube arrays for biologically inspired airflow sensing

The compressive electromechanical response of aligned carbon nanotube (CNT) arrays is evaluated for use as an artificial hair sensor (AHS) transduction element. CNT arrays with heights of 12, 75, and 225 µm are examined. The quasi-static and dynamic sensitivity to force, response time, and signal drift are examined within the range of applied stresses predicted by a mechanical model applicable to the conceptual CNT array-based AHS (0–1 kPa). Each array is highly sensitive to compressive loading, with a maximum observed gauge factor of 114. The arrays demonstrate a repeatable response to dynamic cycling after a break-in period of approximately 50 cycles. Utilizing a four-wire measurement electrode configuration, the change in contact resistance between the array and the electrodes is observed to dominate the electromechanical response of the arrays. The response time of the CNT arrays is of the order of 10 ms. When the arrays are subjected to constant stress, mechanical creep is observed that results in a signal drift that generally diminishes the responsiveness of the arrays, particularly at stress approaching 1 kPa. The results of this study serve as a preliminary proof of concept for utilizing CNT arrays as a transduction mechanism for a proposed artificial hair sensor. Such a low profile and light-weight flow sensor is expected to have application in a number of applications including navigation and state awareness of small air vehicles, similar in function to natural hair cell receptors utilized by insects and bats.

Simulations of wave conditions on an open beach configuration: wind resolution, seaward forcing and whitecapping effects

In the present study, the SWAN model was employed to estimate the wave field on an open sandy beach at the west coast of Portugal. It is the purpose of this work to evaluate the sensitivity of nearshore wave propagation modelling to (i) the wind field resolution, (ii) the type of information used at the offshore boundary to drive the simulations, and (iii) the whitecapping formulation used by the wave model. Wave measurements from an acoustic Doppler current profiler (ADCP) sensor moored in 17 m depth (datum), and operating during a rather stormy period, were used to model comparisons. The comparison showed that no significant differences in the results were found between the two wind field resolutions tested and also that an improvement was observed when the model of van der Westhuysen et al. (2007) is used for the whitecapping dissipation, instead of the default formulation by Komen et al. (1984). Dans la présente étude, le modèle SWAN a été utilisé pour estimer le champ des vagues sur une côte sableuse de la côte Ouest du Portugal ouverte sur l’Océan Atlantique. Cette étude vise à évaluer la sensibilité de la modélisation de la propagation des vagues en zone côtière (i) à la résolution du champ de vent, (ii) au type d’information utilisé pour imposer les conditions sur la frontière maritime et (iii) à le formulation utilisé dans le modèle pour la dissipation due au moutonnement. Les mesures des vagues ont été faites avec un capteur ADCP mouillé par 17 m de profondeur, exploité pendant une période englobant deux épisodes de tempête. La comparaison a permis de montrer qu’il n’y a pas de différences significatives entre les deux résolutions du champ de vent testées, et également qu’une amélioration est observée lorsqu’ est utilisé le modèle van der Westhuysen et al. (2007) pour la dissipation par moutonnement à la place de la formulation par défaut de Komen et al. (1984).

Quorum based sink location service for irregular wireless sensor networks

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires a source node to be aware of the location of a sink. Most existing geographic routing protocols merely assume that the sources can obtain the location of sink by some location service. How can source node efficiently obtain the location of sink is not addressed in detail. In this paper, we propose a quorum based sink location service (QSLS) for irregular profile wireless sensor networks. In this scheme, a sink location announcement packet and a sink location query packet are sent along two trajectories respectively by geographic routing. The node which overheard these two packets near the intersection of the two trajectories informs the source about the sink location. Then the source can send data packets to the sink by geographic routing. The challenge of this paper is that how to guarantee these two trajectories having at least one intersection in arbitrary irregular profile sensor networks. Simulation results show that QSLS is significantly superior to other protocols in terms of control overhead.

1P1-L05 プロファイルセンサを用いた高速3次元計測モジュール : フラットパネルディスプレイとOpenCVを用いた歪み補正方法の検討(光応用-オプトロニクスの未来-)

We have developed an intelligent CMOS sensor named Profile Sensor with sampling rate at 3200Hz of X and Y projection images. The Profile Sensor is a unique CMOS area image sensor aimed at high-speed position sensing by detecting projection images of X and Y-axes. We have constructed a stereo sensing module by using two pieces of Profile Sensor and confirmed the characteristics of the Profile Sensor for high-speed three-dimensional position detection of multi spots by using LEDs or reflectors as a target patterns. We have demonstrated the sensor has high speed and high accurate position measurement capability and the intelligent sensing technique can be useful for industrial and amusement applications.

364 プロファイルセンサを用いた4ロータ型UAVのホバリングに関する研究

364 プロファイルセンサを用いた4ロータ型UAVのホバリングに関する研究

Soil water sensing for water balance, ET and WUE

The soil water balance can be solved for evapotranspiration (ET) using soil water change in storage data from either weighing lysimetry or soil water sensing and measurement, along with data on the other components of the water balance. Weighing lysimeters are expensive and, although accurate, are difficult to manage and afford little replication. Direct soil water measurement by coring is accurate enough, but plagued by spatial variability that induces unwanted variability in the change in soil water storage between dates, and is destructive and time/labor consuming. Here we focus on soil water sensing using the neutron probe and various electromagnetic (EM) sensors (capacitance, time domain reflectometry (TDR) and quasi-TDR) with respect to the relative levels of uncertainty in profile water content, change in soil water storage, and estimates of deep flux; and their impact on estimated ET and water use efficiency (WUE). Studies consistently showed errors up to and >0.05 m3 m−3 for capacitance sensors used in access tubes, which implied errors in soil water flux estimation of up to 50 mm day−1, and calibrations that were so sensitive to soil bulk electrical conductivity (σdc) and temperature that water content and change in storage estimates were rendered unreliable. Also, larger spatial variability of water contents reported by capacitance sensors was tied to the EM field penetration in structured soils around access tubes being non-uniform and influenced by the random arrangement of soil micro-scale water content, σdc and bulk density distribution. Thus, we recommend that profiling sensor systems based on capacitance technology not be used for studies of water balance, ET and WUE, nor for irrigation scheduling. Recommended methods include the neutron probe, direct volumetric soil sampling and, in some cases, conventional time domain reflectometry with waveform capture and analysis. New sensor development efforts should focus on waveguide approaches using TDR technology.

Phase resolved measurements of the statistical flow behavior of a backward‐facing step flow controlled by a sinusoidal Lorentz‐force

AbstractIn order to gain deeper inside into the behavior of a Lorentz‐force controlled flow behind a backward‐facing step, measurements with a laser Doppler velocity profile sensor were undertaken. By varying the frequency of the sinusoidal Lorentz‐force the influence on the turbulence statistics was studied. Moreover, phase resolved measurement data is presented. The results confirm the characteristic frequency determined on basis of the momentum thickness beforehand. The aim of this study is to understand the influence of the different incitation signals and to reduce the reattachment length. The statistical results show a dependency of the turbulence degree on the excitation frequency as well as a deformation of the flow profile behind the step. (© 2011 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

A Spot of Turbulence

AbstractMeasuring technique: An innovative technique enables non‐intrusive, high‐precision measurements of microscopic and macroscopic fluid flows. The laser Doppler velocity profile sensor has huge potential for applications in science and technology.

Determining seam profile tracking of very narrow butt welding on sheet metal

In this study, a welding manipulator has been designed in order to perform the butt-welding operation automatically of cylindrical sheet metals used in natural gas and heating systems. After the design procedure, the elements related to welding manipulator desired, has been defined and the test apparatuses was manufactured. In order to obtain profile of surface that will be welded on sheet metal, 2D laser profile sensor was used. A Personal Computer (PC) based software was developed and tested on the experiment set up in order to define the position of welding torch depends on profile data of welded area. The butt-welding process of two sheet metal shopped cylindrically was carried out automatically on test apparatuses. Key words: Image processing, seam tracking, laser 2D profile sensor, visual control algorithm, butt seam.

Field surveys on suspended matters transport andvariations of water qulity on an intertidal mudflat in the gulf of Ariake Sea using an automatic profiler sensor

Field surveys on suspended matters transport andvariations of water qulity on an intertidal mudflat in the gulf of Ariake Sea using an automatic profiler sensor

Velocity measurements inside the concentration boundary layer during copper-magneto-electrolysis using a novel laser Doppler profile sensor

The evolution of the velocity boundary layer during the initial phase of copper electrolysis under the influence of a magnetic field is studied by using particle image velocimetry and a novel laser Doppler velocity profile sensor. With this new sensor, time-resolved velocity measurements within 400 μm of a vertically aligned cathode in an aqueous 0.05 M CuSO 4-solution are presented. In this way, the complex interaction of Lorentz force and opposing buoyancy-driven convection was studied by measuring the resulting velocity profile inside the concentration boundary layer with a spatial resolution of 15 μm. It is shown that the Lorentz force-driven convection only dominates the velocity boundary layer during the early phase of electrolysis and induces a linear velocity profile near the cathode. The linear relationship between the velocity gradient and Lorentz force is determined. With the onset of the opposing buoyancy-driven convection at the cathode, a duplex structure of the boundary layer appears. Its characteristic quantities, given by the horizontal distances, δ max and δ v = 0 , where the velocity reaches the maximum and where it is equal to zero, remain nearly unchanged, while the maximum velocity, v max , in spite of the counteracting Lorentz force, increases faster as compared to pure natural convection, depending on the current density.

Ontological Problem-Solving Framework for Dynamically Configuring Sensor Systems and Algorithms

The deployment of ubiquitous sensor systems and algorithms has led to many challenges, such as matching sensor systems to compatible algorithms which are capable of satisfying a task. Compounding the challenges is the lack of the requisite knowledge models needed to discover sensors and algorithms and to subsequently integrate their capabilities to satisfy a specific task. A novel ontological problem-solving framework has been designed to match sensors to compatible algorithms to form synthesized systems, which are capable of satisfying a task and then assigning the synthesized systems to high-level missions. The approach designed for the ontological problem-solving framework has been instantiated in the context of a persistence surveillance prototype environment, which includes profiling sensor systems and algorithms to demonstrate proof-of-concept principles. Even though the problem-solving approach was instantiated with profiling sensor systems and algorithms, the ontological framework may be useful with other heterogeneous sensing-system environments.

Highly spatially resolving laser Doppler velocity measurements of the tip clearance flow inside a hard disk drive model

The flow in the tip clearance of a hard disk drive model has been investigated with laser Doppler techniques. The flow was driven by co-rotating disks inside a cylindrical enclosure in order to simulate a hard disk drive used for data storage devices. The main focus of the investigation was on the understanding of complex flow behavior in the narrow gap region between the disk tip and the outer shroud wall, which is supposed to be one of the causes of flow induced vibration of the disks. Experiments in the past have never been able to examine this region because of the lack of the spatial resolution of sensors in the highly three-dimensional flow in the region. In the present investigation, the flow velocity in the tip clearance region was measured with optical measurement techniques for the first time. The flow behaviors are investigated for four different conditions with two different gap widths and two different shapes of the shroud walls with and without ribs. The velocity measurements were taken both with conventional laser Doppler velocimetry and using a laser Doppler velocity profile sensor with a spatial resolution in the micrometer range. The circumferential velocity component was measured along the axial and radial directions. The steep gradients of the circumferential mean velocity in both directions were successfully captured with a high spatial resolution, which was achieved by the velocity profile sensor. From the supplementary investigations, the existence of vortex structures in the tip clearance region was confirmed with a dependence on the shroud gap width and the shroud shape. The interactions of the two boundary layers seem to be the source of the complex three-dimensional behaviors of the flow in this region.

Fine particle turbulence modulation

Streamwise turbulence intensities of fine particulate suspensions were studied in a 26 mm N.B. horizontal pipe loop. Colloidal silica spheres were prepared in 10−4M and 1M KNO3 solutions to control the degree of aggregate formation in the suspension. Using an ultrasonic Doppler velocity profiling sensor, the turbulence intensities of the fine particle suspensions were compared with those of a particle-free flow over a range of Reynolds numbers. At low electrolyte concentration, the silica particles remain dispersed, with the turbulence intensity of the suspension flow comparable with that of the particle-free flow. At high electrolyte concentration, increased particle-particle interaction leads to the formation of particle aggregates which support turbulence augmentation over a critical Reynolds number range. The range of Reynolds numbers over which this turbulence enhancement is observed is limited by both fluid dynamic effects at low Reynolds numbers (Re ≈ 5500) and aggregate breakup at high Reynolds numbers (Re ≈ 8000). © 2010 American Institute of Chemical Engineers AIChE J, 2011