Measurement uncertainty of non-incremental, non-contact, in-situ shape measurements

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Micha Sebastian Schuster ◽  
Robert Kuschmierz ◽  
Jürgen Czarske
Keyword(s):  
Measurement Uncertainty ◽  
Optical Measurement ◽  
Distance Measurement ◽  
Shape Measurement ◽  
Measurement Systems ◽  
Sensor Position ◽  
The Mean ◽  
Fast Rotating ◽  
Rotating Objects

AbstractOptical measurement systems work fast and non-contact and can achieve sub-micron precision. Thus they appear to be well suited for in-situ shape measurement of fast rotating objects such as cutting processes in metal working lathes. Most optical measurement systems, however, allow an axial position measurement only. In order to retrieve the shape of the object from a distance measurement, the distance between the sensor and the centre of the object has to be known. Otherwise, deviations of this distance, for instance due to temperature effects or vibrations, will result in a measurement deviation. In order to allow an absolute shape measurement, which is independent of the sensor position, the mean radius of the rotating object can be retrieved from the object's circumferential velocity. The laser Doppler distance sensor with phase evaluation (P-LDD sensor) allows a simultaneous velocity and distance measurement with high temporal resolution. Thus, the P-LDD sensor allows to measure the mean radius as well as the spatially resolved deviation of the radius independently of the sensor position. In order to quantify the achievable measurement uncertainty, and especially the influence of the temperature the measurement uncertainty budget is derived and considers random as well as systematic errors. It is shown that the P-LDD sensor allows an absolute, three-dimensional shape measurement of fast rotating objects with sub-micron uncertainty. The systematic measurement uncertainty of the absolute shape due to the temperature amounts to only 200 nm/K. Thus the P-LDD sensor is not dependent on temperature-controlled laboratories but can be employed directly in the production process (in-situ or in-process).

High-speed laser interferometric distance sensor with reference mirror oscillating at ultrasonic frequencies

2019 ◽  
Vol 86 (3) ◽  
pp. 164-174 ◽  
Author(s):  
Sebastian Hagemeier ◽  
Stanislav Tereschenko ◽  
Peter Lehmann
Keyword(s):  
High Speed ◽  
Optical Measurement ◽  
Limited Range ◽  
Distance Measurement ◽  
Reference Mirror ◽  
Acquisition Rate ◽  
Measurement Systems ◽  
3D Topography ◽  
Distance Sensor ◽  
Laser Interferometric

AbstractOptical measurement systems are an important part of the portfolio of 3D topography sensors. By precise, contactless and rapid measurements these sensors constitute an alternative to tactile instruments. In this contribution the principle of a laser interferometric distance sensor is presented, which in combination with lateral scan axes acts as a topography sensor and also as distance sensor for the compensation of vibrations in a coherence scanning Linnik interferometer. An advantage of this distance sensor is its high acquisition rate of height values, which in case of working as a topography sensor enables high scan velocities as it is demonstrated at a chirp standard measured with a scan velocity of 80 mm/s. This is much higher than the scan velocity of tactile instruments, which are typically limited up to 1 mm/s. In addition, the compensation of vibration disturbances demonstrates the capability of the fast distance measurement.In contrast to other existing high-speed point sensors the relevant components are mass products. This keeps the costs of the sensor setup in a limited range. Furthermore, the sensor shows potential of much higher measurement rates than 116 kHz provided by the sensor used here.

scholarly journals Transparent multispectral photodetectors mimicking the human visual system

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Qitong Li ◽  
Jorik van de Groep ◽  
Yifei Wang ◽  
Pieter G. Kik ◽  
Mark L. Brongersma
Keyword(s):  
Optical Measurement ◽  
Electronic Devices ◽  
Critical Role ◽  
Semiconductor Nanowires ◽  
Optical Resonance ◽  
Radiative Coupling ◽  
Measurement Systems ◽  
Optical Resonances ◽  
Dielectric Interfaces

Abstract Compact and lightweight photodetection elements play a critical role in the newly emerging augmented reality, wearable and sensing technologies. In these technologies, devices are preferred to be transparent to form an optical interface between a viewer and the outside world. For this reason, it is of great value to create detection platforms that are imperceptible to the human eye directly onto transparent substrates. Semiconductor nanowires (NWs) make ideal photodetectors as their optical resonances enable parsing of the multi-dimensional information carried by light. Unfortunately, these optical resonances also give rise to strong, undesired light scattering. In this work, we illustrate how a new optical resonance arising from the radiative coupling between arrayed silicon NWs can be harnessed to remove reflections from dielectric interfaces while affording spectro-polarimetric detection. The demonstrated transparent photodetector concept opens up promising platforms for transparent substrates as the base for opto-electronic devices and in situ optical measurement systems.

scholarly journals Gear Shape Measurement Potential of Laser Triangulation and Confocal-Chromatic Distance Sensors

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 937
Author(s):  
Marc Pillarz ◽  
Axel von Freyberg ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
Measurement Uncertainty ◽  
Surface Properties ◽  
Optical Sensors ◽  
Laser Triangulation ◽  
Shape Measurement ◽  
Full Potential ◽  
Position Measurement ◽  
Standard Measurement ◽  
Measurement Systems ◽  
Measurement Approach

The demand for extensive gear shape measurements with single-digit µm uncertainty is growing. Tactile standard gear tests are precise but limited in speed. Recently, faster optical gear shape measurement systems have been examined. Optical gear shape measurements are challenging due to potential deviation sources such as the tilt angles between the surface normal and the sensor axis, the varying surface curvature, and the surface properties. Currently, the full potential of optical gear shape measurement systems is not known. Therefore, laser triangulation and confocal-chromatic gear shape measurements using a lateral scanning position measurement approach are studied. As a result of tooth flank standard measurements, random effects due to surface properties are identified to primarily dominate the achievable gear shape measurement uncertainty. The standard measurement uncertainty with the studied triangulation sensor amounts to >10 µm, which does not meet the requirements. The standard measurement uncertainty with the confocal-chromatic sensor is <6.5 µm. Furthermore, measurements on a spur gear show that multiple reflections do not influence the measurement uncertainty when measuring with the lateral scanning position measurement approach. Although commercial optical sensors are not designed for optical gear shape measurements, standard uncertainties of <10 µm are achievable for example with the applied confocal-chromatic sensor, which indicates the further potential for optical gear shape measurements.

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Drug Loading ◽  
In Vitro Release ◽  
Formulation Development ◽  
Ciprofloxacin Hydrochloride ◽  
Potential Value ◽  
The Mean ◽  
In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

scholarly journals Forensic Investigation of Four Monitored Green Infrastructure Inlets

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1787
Author(s):  
Leena J. Shevade ◽  
Franco A. Montalto
Keyword(s):  
Measurement Uncertainty ◽  
Green Infrastructure ◽  
Stormwater Management ◽  
Catchment Area ◽  
Low Flow ◽  
Inflow Rate ◽  
Forensic Investigation ◽  
Flow Conditions ◽  
The Mean

Green infrastructure (GI) is viewed as a sustainable approach to stormwater management that is being rapidly implemented, outpacing the ability of researchers to compare the effectiveness of alternate design configurations. This paper investigated inflow data collected at four GI inlets. The performance of these four GI inlets, all of which were engineered with the same inlet lengths and shapes, was evaluated through field monitoring. A forensic interpretation of the observed inlet performance was conducted using conclusions regarding the role of inlet clogging and inflow rate as described in the previously published work. The mean inlet efficiency (meanPE), which represents the percentage of tributary area runoff that enters the inlet was 65% for the Nashville inlet, while at Happyland the NW inlet averaged 30%, the SW inlet 25%, and the SE inlet 10%, considering all recorded events during the monitoring periods. The analysis suggests that inlet clogging was the main reason for lower inlet efficiency at the SW and NW inlets, while for the SE inlet, performance was compromised by a reverse cross slope of the street. Spatial variability of rainfall, measurement uncertainty, uncertain tributary catchment area, and inlet depression characteristics are also correlated with inlet PE. The research suggests that placement of monitoring sensors should consider low flow conditions and a strategy to measure them. Additional research on the role of various maintenance protocols in inlet hydraulics is recommended.

scholarly journals Nano-imprinted subwavelength gratings as polarizing beamsplitters

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Julian Wüster ◽  
Yannick Bourgin ◽  
Patrick Feßer ◽  
Arne Behrens ◽  
Stefan Sinzinger
Keyword(s):  
Nanoimprint Lithography ◽  
Optical Measurement ◽  
Design Method ◽  
Optical Systems ◽  
Surface Metrology ◽  
Measurement Systems ◽  
Common Path ◽  
Dielectric Coatings ◽  
Subwavelength Gratings ◽  
Wide Range

AbstractPolarizing beamsplitters have numerous applications in optical systems, such as systems for freeform surface metrology. They are classically manufactured from birefringent materials or with stacks of dielectric coatings. We present a binary subwavelength-structured form-birefringent diffraction grating, which acts as a polarizing beamsplitter for a wide range of incidence angles −30∘…+30∘. We refine the general design method for such hybrid gratings. We furthermore demonstrate the manufacturing steps with Soft-UV-Nanoimprint-Lithography, as well as the experimental verification, that the structure reliably acts as a polarizing beamsplitter. The experimental results show a contrast in efficiency for TE- and TM-polarization of up to 1:18 in the first order, and 34:1 in the zeroth order. The grating potentially enables us to realize integrated compact optical measurement systems, such as common-path interferometers.

scholarly journals Detection of foot contact in treadmill running with inertial and optical measurement systems

2021 ◽  
pp. 110419
Author(s):  
Jasper Reenalda ◽  
Marit A. Zandbergen ◽  
Jelle D. Harbers ◽  
Max R. Paquette ◽  
Clare E. Milner
Keyword(s):  
Optical Measurement ◽  
Treadmill Running ◽  
Measurement Systems

scholarly journals Investigation of dominant traveling 10-day wave components using long-term MERRA-2 database

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Chunming Huang ◽  
Wei Li ◽  
Shaodong Zhang ◽  
Gang Chen ◽  
Kaiming Huang ◽  
...  
Keyword(s):  
Flow Instability ◽  
Transmission Condition ◽  
Wave Number ◽  
Mean Flow ◽  
Excited Wave ◽  
Propagating Waves ◽  
Zonal Wave Number ◽  
The Mean

AbstractThe eastward- and westward-traveling 10-day waves with zonal wavenumbers up to 6 from surface to the middle mesosphere during the recent 12 years from 2007 to 2018 are deduced from MERRA-2 data. On the basis of climatology study, the westward-propagating wave with zonal wave number 1 (W1) and eastward-propagating waves with zonal wave numbers 1 (E1) and 2 (E2) are identified as the dominant traveling ones. They are all active at mid- and high-latitudes above the troposphere and display notable month-to-month variations. The W1 and E2 waves are strong in the NH from December to March and in the SH from June to October, respectively, while the E1 wave is active in the SH from August to October and also in the NH from December to February. Further case study on E1 and E2 waves shows that their latitude–altitude structures are dependent on the transmission condition of the background atmosphere. The presence of these two waves in the stratosphere and mesosphere might have originated from the downward-propagating wave excited in the mesosphere by the mean flow instability, the upward-propagating wave from the troposphere, and/or in situ excited wave in the stratosphere. The two eastward waves can exert strong zonal forcing on the mean flow in the stratosphere and mesosphere in specific periods. Compared with E2 wave, the dramatic forcing from the E1 waves is located in the poleward regions.

Estimating Global Ocean Heat Content Changes in the Upper 1800 m since 1950 and the Influence of Climatology Choice*

2014 ◽  
Vol 27 (5) ◽  
pp. 1945-1957 ◽  
Author(s):  
John M. Lyman ◽  
Gregory C. Johnson
Keyword(s):  
Heat Content ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Ocean Temperature ◽  
Vertical Separation ◽  
Ocean Heat Uptake ◽  
Expendable Bathythermograph ◽  
Heat Uptake ◽  
The Mean

Abstract Ocean heat content anomalies are analyzed from 1950 to 2011 in five distinct depth layers (0–100, 100–300, 300–700, 700–900, and 900–1800 m). These layers correspond to historic increases in common maximum sampling depths of ocean temperature measurements with time, as different instruments—mechanical bathythermograph (MBT), shallow expendable bathythermograph (XBT), deep XBT, early sometimes shallower Argo profiling floats, and recent Argo floats capable of worldwide sampling to 2000 m—have come into widespread use. This vertical separation of maps allows computation of annual ocean heat content anomalies and their sampling uncertainties back to 1950 while taking account of in situ sampling advances and changing sampling patterns. The 0–100-m layer is measured over 50% of the globe annually starting in 1956, the 100–300-m layer starting in 1967, the 300–700-m layer starting in 1983, and the deepest two layers considered here starting in 2003 and 2004, during the implementation of Argo. Furthermore, global ocean heat uptake estimates since 1950 depend strongly on assumptions made concerning changes in undersampled or unsampled ocean regions. If unsampled areas are assumed to have zero anomalies and are included in the global integrals, the choice of climatological reference from which anomalies are estimated can strongly influence the global integral values and their trend: the sparser the sampling and the bigger the mean difference between climatological and actual values, the larger the influence.

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