Electrochemical pH regulation in droplet microfluidics

Lab on a Chip ◽  
2022 ◽  
Author(s):  
Logan M. Wilder ◽  
Jonathan R. Thompson ◽  
Richard M. Crooks

The pH of droplets moving through a microchannel is regulated in real time by water electrolysis. Resulting droplet pHs are within ±0.1 pH units of the predicted values.

2018 ◽  
Vol 71 (4) ◽  
pp. 769-787 ◽  
Author(s):  
Ahmed El-Mowafy

Real-time Precise Point Positioning (PPP) relies on the use of accurate satellite orbit and clock corrections. If these corrections contain large errors or faults, either from the system or by meaconing, they will adversely affect positioning. Therefore, such faults have to be detected and excluded. In traditional PPP, measurements that have faulty corrections are typically excluded as they are merged together. In this contribution, a new PPP model that encompasses the orbit and clock corrections as quasi-observations is presented such that they undergo the fault detection and exclusion process separate from the observations. This enables the use of measurements that have faulty corrections along with predicted values of these corrections in place of the excluded ones. Moreover, the proposed approach allows for inclusion of the complete stochastic information of the corrections. To facilitate modelling of the orbit and clock corrections as quasi-observations, International Global Navigation Satellite System Service (IGS) real-time corrections were characterised over a six-month period. The proposed method is validated and its benefits are demonstrated at two sites using three days of data.


2014 ◽  
Vol 49 (4) ◽  
pp. 179-189 ◽  
Author(s):  
J. Z. Kalita ◽  
Z. Rzepecka ◽  
G. Krzan

ABSTRACT Among many sources of errors that influence Global Navigation Satellite System (GNSS) observations, tropospheric delay is one of the most significant. It causes nonrefractive systematic bias in the observations on the level of several meters, depending on the atmospheric conditions. Tropospheric delay modelling plays an important role in precise positioning. The current models use numerical weather data for precise estimation of the parameters that are provided as a part of the Global Geodetic Observation System (GGOS). The purpose of this paper is to analyze the tropospheric data provided by the GGOS Atmosphere Service conducted by the Vienna University of Technology. There are predicted and final delay data available at the Service. In real time tasks, only the predicted values can be used. Thus it is very useful to study accuracy of the forecast delays. Comparison of data sets based on predicted and real weather models allows for conclusions concerning possibility of using the former for real time positioning applications. The predicted values of the dry tropospheric delay component, both zenith and mapped, can be safely used in real time PPP applications, but on the other hand, while using the wet predicted values, one should be very careful.


2008 ◽  
Vol 80 (18) ◽  
pp. 7063-7067 ◽  
Author(s):  
Monpichar Srisa-Art ◽  
Emily C. Dyson ◽  
Andrew J. deMello ◽  
Joshua B. Edel

1981 ◽  
Vol 63 ◽  
pp. 141-146
Author(s):  
Ivan I. Mueller ◽  
B. S. Rajal ◽  
Y. S. Zhu

AbstractPolar motion coordinates obtained during the Merit short campaign by various techniques, as well as their variations, have been compared directly and through a smoothing procedure. In the direct comparison, values at selected dates were differenced in all combinations and the rms values computed. Through the smoothing procedure the amplitudes of the annual and Chandler motions as well as the centers of the polhodes were estimated and compared with predicted values based on the previous six years of polar motion data. The results are somewhat inconclusive, mainly due to the shortness of the campaign and the (practically) real time data reduction techniques. To resolve the issue of possible systematic differences, the proposed MERIT main campaign seems an absolute necessity.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Patrick Hardinge ◽  
Divesh K. Baxani ◽  
Thomas McCloy ◽  
James A. H. Murray ◽  
Oliver K. Castell

AbstractMicrofluidic droplet generation affords precise, low volume, high throughput opportunities for molecular diagnostics. Isothermal DNA amplification with bioluminescent detection is a fast, low-cost, highly specific molecular diagnostic technique that is triggerable by temperature. Combining loop-mediated isothermal nucleic acid amplification (LAMP) and bioluminescent assay in real time (BART), with droplet microfluidics, should enable high-throughput, low copy, sequence-specific DNA detection by simple light emission. Stable, uniform LAMP–BART droplets are generated with low cost equipment. The composition and scale of these droplets are controllable and the bioluminescent output during DNA amplification can be imaged and quantified. Furthermore these droplets are readily incorporated into encapsulated droplet interface bilayers (eDIBs), or artificial cells, and the bioluminescence tracked in real time for accurate quantification off chip. Microfluidic LAMP–BART droplets with high stability and uniformity of scale coupled with high throughput and low cost generation are suited to digital DNA quantification at low template concentrations and volumes, where multiple measurement partitions are required. The triggerable reaction in the core of eDIBs can be used to study the interrelationship of the droplets with the environment and also used for more complex chemical processing via a self-contained network of droplets, paving the way for smart soft-matter diagnostics.


2018 ◽  
Vol 2 (9) ◽  
pp. 1974-1978 ◽  
Author(s):  
Fabian L. Huber ◽  
Sebastian Amthor ◽  
Benjamin Schwarz ◽  
Boris Mizaikoff ◽  
Carsten Streb ◽  
...  

The simultaneous, real time observation of oxygen evolution in the gas phase and in solution enables advanced mechanistic studies which are critical for technologies including water electrolysis, fuel cells, oxidation catalysis and metal–air batteries.


Author(s):  
David A.P. Grimm ◽  
Jamie C. Gorman ◽  
Ron H. Stevens ◽  
Trysha L. Galloway ◽  
Ann M. Willemsen-Dunlap ◽  
...  

Real-time analysis of team communication data to detect anomalies and/or perturbations in the team environment is an ideal method to improve on teams’ interactions and responses to potential crises. In this paper, we demonstrate a method to detect anomalies through observing communication patterns of neurosurgery teams. We simulated the real-time process by analyzing previously collected communication data to assess the effectiveness of a nonlinear prediction model to detect anomalies. We compared predicted values of communication determinism (a measure of how organized communication patterns are) to previous values in each team’s time series. These deviations formed a separate root mean square error (RMSE) time series, and we examined the magnitudes of the RMSE time series at the points of known perturbations. Additionally, we examined the effect of window size on perturbation detection. We found that our nonlinear prediction model accurately detected the perturbations and shows promise for future real-time analysis.


Author(s):  
Andrew Wu ◽  
Geir Hareland

This paper introduces the functionality of a new type of Autodriller software system, which can acquire downhole weight on bit (DWOB) based on surface rig measurement. Field tests are performed, including DWOB measured by downhole measuring tools and the hookload below the top drive using a TTS (Torque and Tension Sub). Three sets of drilling data from three horizontal wells in Western Canada were utilized to verify the models of this new Autodriller system. DWOB comparisons between the model and the measuring tools were carried out. The comparisons indicate a good agreement between the downhole measured DWOB and the new Autodriller predicted values. The difference between the new Autodriller prediction and downhole measured DWOB can be quantified using rooted mean square error (RMSE) or relative error (RE). This paper also analyzes the differences in some sections, and some measures are suggested to potentially reduce these differences. The new Autodriller is a closed loop control system which can automatically in real-time adjust surface weight on bit (SWOB) so that the DWOB is accurate, which will directly improve the performance of drill bits, and decrease the cost of drilling, especially in directional well drilling applications.


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