scholarly journals Cantilever-Droplet-Based Sensing of Magnetic Particle Concentrations in Liquids

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4758 ◽  
Author(s):  
Wilson Ombati Nyang’au ◽  
Andi Setiono ◽  
Maik Bertke ◽  
Harald Bosse ◽  
Erwin Peiner
Keyword(s):  
Water Droplet ◽  
Water Evaporation ◽  
Ambient Conditions ◽  
Evaporation Time ◽  
Particle Count ◽  
Microcantilever Sensors ◽  
Small Water ◽  
Monodispersed Particles ◽  
Sensing Applications ◽  
Cantilever Sensor

Cantilever-based sensors have attracted considerable attention in the recent past due to their enormous and endless potential and possibilities coupled with their dynamic and unprecedented sensitivity in sensing applications. In this paper, we present a technique that involves depositing and vaporizing (at ambient conditions) a particle-laden water droplet onto a defined sensing area on in-house fabricated and commercial-based silicon microcantilever sensors. This process entailed the optimization of dispensing pressure and time to generate and realize a small water droplet volume (Vd = 49.7 ± 1.9 pL). Moreover, we monitored the water evaporation trends on the sensing surface and observed total evaporation time per droplet of 39.0 ± 1.8 s against a theoretically determined value of about 37.14 s. By using monodispersed particles in water, i.e., magnetic polystyrene particles (MPS) and polymethyl methacrylate (PMMA), and adsorbing them on a dynamic cantilever sensor, the mass and number of these particles were measured and determined comparatively using resonant frequency response measurements and SEM particle count analysis, respectively. As a result, we observed and reported monolayer particles assembled on the sensor with the lowest MPS particles count of about 19 ± 2.

Influence of Water Droplet Size and Temperature on Wet Compression

2007 ◽  
Author(s):  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
S. Ingistov
Keyword(s):  
Gas Turbine ◽  
Water Droplet ◽  
Droplet Diameter ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Air Cooling ◽  
Compression Process ◽  
Two Phase ◽  
Wet Compression

In the last years, among all different gas turbine inlet air cooling techniques, an increasing attention to fogging approach is dedicated. The various fogging strategies seem to be a good solution to improve gas turbine or combined cycle produced power with low initial investment cost and less installation downtime. In particular, overspray fogging and interstage injection involve two-phase flow consideration and water evaporation during compression process (also known as wet compression). According to the Author’s knowledge, the field of wet compression is not completely studied and understood. In the present paper, all the principal aspects of wet compression and in particular the influence of injected water droplet diameter and surface temperature, and their effect on gas turbine performance and on the behavior of the axial compressor (change in axial compressor performance map due to the water injection, redistribution of stage load, etc.) are analyzed by using a calculation code, named IN.FO.G.T.E. (INterstage FOgging Gas Turbine Evaluation), developed and validated by the Authors.

Manufacture of Microcantilever Sensors

2005 ◽  
Author(s):  
Andrew W. McFarland ◽  
Jonathan S. Colton ◽  
Daniel Cox ◽  
Steven Y. Liang
Keyword(s):  
Machine Tool ◽  
Mechanical Response ◽  
Surface Force ◽  
Depth Of Cut ◽  
Feed Speed ◽  
Machining Parameters ◽  
Form Accuracy ◽  
Microcantilever Sensors ◽  
Micro Scale ◽  
Sensing Applications

Mechanical micro machining is an emerging technology with many potential benefits and equally great challenges. The push to develop processes and tools capable of micro scale fabrication is a result of the widespread drive to reduce part and feature size. One important factor that contributes to the ability to machine at the microscale level is the overall size of the machine tool due to the effects of thermal, static, and dynamic stabilities. This paper explores the technical feasibility of miniaturized machine tools capable of fabricating features and parts on the micro scale in terms of depth of cut and part form accuracy. It develops a machine tool and examines its capabilities through benchmarking tests and the making of precision dies for the injection molding of microcantilever parts. The design and configuration of a miniaturized vertical machining center of overall dimension less than 300 mm on a side is presented and the component specifications discussed. The six axis machine has linear positioning resolution of 4 nm by 10 nm by 10 nm, with accuracy on the order of 0.3 μm, in the height, feed, and cross feed directions. The work volume as defined by the ranges of axes travel are 4 mm by 25 mm by 25 mm in the height, feed, and cross feed and 20 degrees in the rotational space. To quantify the performance capability of the miniaturized machine tool as a system, a series of evaluation tests were implemented based on linear and arch trajectories over a range of feed speed and depth of cut conditions. Test results suggest that micro level form accuracy and sub-micron level finish are generally achievable for parts with moderate curvature and gradient in the geometry under selected machining parameters and conditions. An injection mold was made of steel with this machine and plastic microcantilevers fabricated. Plastic microcantilevers are appropriate for sensing applications such as surface probe microscopy. The microcantilevers, made from polystyrene, were 464 to 755 μm long, 130 μm wide and only 6–9 μm thick. They showed very good uniformity, reproducibility, and appropriate mechanical response for use as sensors in surface force microscopy.

Enhanced Evaporation of Microscale Droplets With an Infrared Laser

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Luis A. Ferraz-Albani ◽  
Alberto Baldelli ◽  
Chrissy J. Knapp ◽  
Wolfgang Jäger ◽  
Reinhard Vehring ◽  
...  
Keyword(s):  
Water Droplet ◽  
Droplet Evaporation ◽  
Radiant Flux ◽  
Droplet Temperature ◽  
Ambient Conditions ◽  
Drying Time ◽  
Proposed Model ◽  
Environment Temperature ◽  
Order Of Magnitude ◽  
Surface Area Change

Enhancement of water droplet evaporation by added infrared radiation was modeled and studied experimentally in a vertical laminar flow channel. Experiments were conducted on droplets with nominal initial diameters of 50 μm in air with relative humidities ranging from 0% to 90% RH. A 2800 nm laser was used with radiant flux densities as high as 4 × 105 W/m2. Droplet size as a function of time was measured by a shadowgraph technique. The model assumed quasi-steady behavior, a low Biot number liquid phase, and constant gas–vapor phase material properties, while the experimental results were required for model validation and calibration. For radiant flux densities less than 104 W/m2, droplet evaporation rates remained essentially constant over their full evaporation, but at rates up to 10% higher than for the no radiation case. At higher radiant flux density, the surface-area change with time became progressively more nonlinear, indicating that the radiation had diminished effects on evaporation as the size of the droplets decreased. The drying time for a 50 μm water droplet was an order of magnitude faster when comparing the 106 W/m2 case to the no radiation case. The model was used to estimate the droplet temperature. Between 104 and 5 × 105 W/m2, the droplet temperature changed from being below to above the environment temperature. Thus, the direction of conduction between the droplet and the environment also changed. The proposed model was able to predict the changing evaporation rates for droplets exposed to radiation for ambient conditions varying from dry air to 90% relative humidity.

Direct filtration with preozonation for small water treatment systems

2004 ◽  
Vol 48 (11-12) ◽  
pp. 473-479 ◽  
Author(s):  
E. Yüksel ◽  
Ö Akgiray ◽  
E. Soyer
Keyword(s):  
Treatment Method ◽  
Silica Sand ◽  
Particle Removal ◽  
Raw Water ◽  
Particle Count ◽  
Direct Filtration ◽  
Small Water ◽  
On Line ◽  
Very High ◽  
Different Water Sources

The possibility of applying preozonation followed by direct filtration without the use of a coagulant is investigated. Filtration experiments have been carried out using four different water sources within Istanbul. A 1 m deep bed of 0.8-1.2 mm silica sand was used as the filter medium. The filter was operated at a rate of 11.5 m/hr. Raw water turbidities ranged from 2.3 NTU to 10.0 NTU. Effluent turbidity and particle count values were monitored using an on-line turbidimeter and an on-line particle counter. With all the waters studied in this work, preozonation improved particle removal in direct filtration. With three of the mentioned waters, it was possible to achieve turbidity values below 1.0 NTU without a coagulant by applying ozone at a rate between 1.7-1.8 mg/L. It was not possible to reduce the turbidity of one of the waters to below 2.7 NTU even with very high ozone dosages. The need for pilot testing before deciding if this treatment method is applicable to a given water is underlined.

scholarly journals A ciliate memorizes the geometry of a swimming arena

2016 ◽  
Vol 13 (118) ◽  
pp. 20160155 ◽  
Author(s):  
Itsuki Kunita ◽  
Tatsuya Yamaguchi ◽  
Atsushi Tero ◽  
Masakazu Akiyama ◽  
Shigeru Kuroda ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Water Droplet ◽  
Adaptive Behaviour ◽  
Small Water ◽  
Short Period ◽  
Reversal Frequency ◽  
Slow Rise ◽  
Swimming Trajectories ◽  
Shape And Size

Previous studies on adaptive behaviour in single-celled organisms have given hints to the origin of their memorizing capacity. Here we report evidence that a protozoan ciliate Tetrahymena has the capacity to learn the shape and size of its swimming space. Cells confined in a small water droplet for a short period were found to recapitulate circular swimming trajectories upon release. The diameter of the circular trajectories and their duration reflected the size of the droplet and the period of confinement. We suggest a possible mechanism for this adaptive behaviour based on a Ca 2+ channel. In our model, repeated collisions with the walls of a confining droplet result in a slow rise in intracellular calcium that leads to a long-term increase in the reversal frequency of the ciliary beat.

Bioinspired Poly(vinyl alcohol) Film Actuator Powered by Water Evaporation under Ambient Conditions

2020 ◽  
Vol 305 (6) ◽  
pp. 2000145
Author(s):  
Sitong Wang ◽  
Shuang Yan ◽  
Li Zhang ◽  
Huhu Zhao ◽  
Tian Yang ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Water Evaporation ◽  
Poly Vinyl Alcohol ◽  
Ambient Conditions

Laser Beam-Hygroscopic Aerosol Interactions

1977 ◽  
Vol 99 (2) ◽  
pp. 281-286 ◽  
Author(s):  
G. E. Caledonia ◽  
J. D. Teare
Keyword(s):  
Steady State ◽  
Laser Beam ◽  
Water Droplet ◽  
Atmospheric Aerosol ◽  
Phase Shifts ◽  
Time Dependent ◽  
Small Water ◽  
Steady State Solutions

A model for the prediction of the temperature and vapor fields created about a small water droplet undergoing irradiation by a laser beam has been developed. Time-dependent and steady-state solutions of the model are discussed. Estimates of characteristic phase shifts to be expected in propagating through standard atmospheric aerosol distributions are also presented. While the model is quite general, the calculations are limited to DF laser wavelengths.

scholarly journals Impact of type of salt and ambient conditions on saline water evaporation from porous media

2017 ◽  
Vol 105 ◽  
pp. 154-161 ◽  
Author(s):  
Salomé M.S. Shokri-Kuehni ◽  
Mansoureh Norouzi Rad ◽  
Colin Webb ◽  
Nima Shokri
Keyword(s):  
Porous Media ◽  
Saline Water ◽  
Water Evaporation ◽  
Ambient Conditions

Resonant Sensors for Microfluidic Applications

2006 ◽  
Vol 951 ◽  
Author(s):  
Florentina Niebelschütz ◽  
Katja Tonisch ◽  
Volker Cimalla ◽  
Klemens Brückner ◽  
Ralf Stephan ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Aluminum Nitride ◽  
Microfluidic Channels ◽  
Biological Cells ◽  
Ambient Conditions ◽  
Resonant Sensors ◽  
Sensing Applications ◽  
Resonance Shift ◽  
Active Layers ◽  
Physical Sensor

ABSTRACTIn this work we present both resonators working at ambient conditions and their first application as a biological and physical sensor. Singly- and doubly-clamped resonators of different geometries were realized using active layers of silicon carbide and aluminum nitride. The resonators were excited by magneto-motive actuation. The quality factor reached 350 and 50000 in air and in vacuum (2-5 10−5 mbar), respectively, which is sufficient for sensing applications in air. The resonance shift caused by mass loadings in the range of picograms and by single biological cells was measured at ambient conditions. Initial non-resonant measurements in liquids such as propanol were performed to investigate the possibility of viscosity measurements in small volumes such as microfluidic channels and droplets.

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