scholarly journals Tomographic Measurement of Ammonia Distribution on a Hot Gas Test Bench

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 876
Author(s):  
Bernhard Fischbacher ◽  
Bernhard Lechner ◽  
Bernhard Brandstätter
Keyword(s):  
Test Bench ◽  
Optical Measurement ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
High Temporal Resolution ◽  
Exhaust Pipe ◽  
Transimpedance Amplifiers ◽  
Gas Streams ◽  
Hot Gas

In situ optical measurement systems for gas detection with high temporal resolution enable new possibilities of detection opportunities for continuous pipe gas streams. A tomographic absorption-based measurement system has been developed to detect the ammonia (NH3) concentration distribution within an exhaust pipe on a hot gas test bench. Multiple ammonia line concentrations are measured in situ by applying nondispersive absorption spectroscopy in the deep ultraviolet (DUV) region. The detectors consist of photodiodes in combination with optimized transimpedance amplifiers (TIV) allowing high sampling rates up to 3 kHz while providing a high signal-to-noise ratio (SNR). Despite the short path length of only eight centimeters a detection limit of 1 ppm has been achieved.

Optical measurement of the corneal oscillation for the determination of the intraocular pressure

2019 ◽  
Vol 64 (4) ◽  
pp. 471-480 ◽  
Author(s):  
Jan Osmers ◽  
Michael Sorg ◽  
Andreas Fischer
Keyword(s):  
Intraocular Pressure ◽  
Optical Measurement ◽  
Signal To Noise Ratio ◽  
Significant Risk ◽  
High Signal ◽  
High Temporal Resolution ◽  
Signal To Noise ◽  
Handheld Device ◽  
Noise Ratio ◽  
Reference Sensor

Abstract Motivation Glaucoma is currently the most common irreversible cause of blindness worldwide. A significant risk factor is an individually increased intraocular pressure (IOP). A precise measurement method is needed to determine the IOP in order to support the diagnosis of the disease and to monitor the outcome of the IOP reduction as a medical intervention. A handheld device is under development with which the patient can perform self-measurements outside the clinical environment. Method For the measurement principle of the self-tonometer the eye is acoustically excited to oscillate, which is analyzed and attributed to the present IOP. In order to detect the corneal oscillation, an optical sensor is required which meets the demands of a compact, battery driven self-tonometer. A combination of an infrared diode and a phototransistor provides a high-resolution measurement of the corneal oscillation in the range of 10 μm–150 μm, which is compared to a reference sensor in the context of this study. By means of an angular arrangement of the emitter and the detector, the degree of reflected radiation of the cornea can be increased, allowing a measurement with a high signal-to-noise ratio. Results By adjusting the angle of incidence between the detector and the emitter, the signal-to-noise ratio was improved by 40 dB which now allows reasonable measurements of the corneal oscillation. For low amplitudes (10 μm) the signal-to-noise ratio is 10% higher than that of the commercial reference sensor. On the basis of amplitude variations at different IOP levels, the estimated standard uncertainty amounts to <0.5 mm Hg in the physiological pressure range with the proposed measuring approach. Conclusion With a compact and cost-effective approach, that suits the requirements for a handheld self-tonometer, the corneal oscillation can be detected with high temporal resolution. The cross-sensitivity of the sensor concept concerning a distance variation can be reduced by adding a distance sensor. Existing systematic influences of corneal biomechanics will be integrated in the sensor concept as a consecutive step.

scholarly journals Ammonia Distribution Measurement on a Hot Gas Test Bench Applying Tomographical Optical Methods

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 896 ◽  
Author(s):  
Bernhard Fischbacher ◽  
Bernhard Lechner ◽  
Bernhard Brandstätter
Keyword(s):  
Inverse Problem ◽  
Concentration Distribution ◽  
Test Bench ◽  
Exhaust System ◽  
Ammonia Concentration ◽  
Optical Methods ◽  
Ultraviolet Region ◽  
High Signal ◽  
Time Step ◽  
Hot Gas

Measuring the distribution of gas concentration is a very common problem in a variety of technological fields. Depending on the detectability of the gas, as well as the technological progress of the sector, different methods are used. In this paper, we present a device and methods to detect the ammonia concentration distribution in the exhaust system of diesel engines in order to increase the performance of the exhaust aftertreatment system. The device has been designed for usage on a hot gas test bench simulating exhaust gas conditions. It consists of multiple optical beams measuring ammonia line concentrations by applying nondispersive absorption spectroscopy in the deep ultraviolet region. The detectors consist of photodiodes allowing high sampling rates up to 3 kHz while providing a high signal-to-noise ratio. A detection limit of only 1 ppm has been achieved despite the short path length of only eight centimeters. The obtained line concentrations form an inverse problem. The methodology of the tomographic techniques is described in detail in order to best solve the inverse problem and obtain the ammonia concentration distribution images for each time step.

scholarly journals Multi-analyser detector (MAD) for high-resolution and high-energy powder X-ray diffraction

2021 ◽  
Vol 28 (1) ◽  
pp. 146-157
Author(s):  
Alexander Schökel ◽  
Martin Etter ◽  
Andreas Berghäuser ◽  
Alexander Horst ◽  
Dirk Lindackers ◽  
...  
Keyword(s):  
High Resolution ◽  
Signal To Noise Ratio ◽  
High Energy ◽  
High Signal ◽  
X Ray Diffraction ◽  
Stepper Motors ◽  
In Operando ◽  
Characterization Of Materials

For high-resolution powder diffraction in material science, high photon energies are necessary, especially for in situ and in operando experiments. For this purpose, a multi-analyser detector (MAD) was developed for the high-energy beamline P02.1 at PETRA III of the Deutsches Elektronen-Synchrotron (DESY). In order to be able to adjust the detector for the high photon energies of 60 keV, an individually adjustable analyser–crystal setup was designed. The adjustment is performed via piezo stepper motors for each of the ten channels. The detector shows a low and flat background as well as a high signal-to-noise ratio. A range of standard materials were measured for characterizing the performance. Two exemplary experiments were performed to demonstrate the potential for sophisticated structural analysis with the MAD: (i) the structure of a complex material based on strontium niobate titanate and strontium niobate zirconate was determined and (ii) an in situ stroboscopy experiment with an applied electric field on a highly absorbing piezoceramic was performed. These experiments demonstrate the capabilities of the new MAD, which advances the frontiers of the structural characterization of materials.

scholarly journals First Steps towards a Super-Compact In-Situ Laser-Induced-Incandescence Sensor System

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 1017 ◽  
Author(s):  
Martin Kupper ◽  
Jožef Pulko ◽  
Martin Kraft ◽  
Alexander Bergmann
Keyword(s):  
High Power ◽  
Optical Measurement ◽  
Combustion Engine ◽  
Sensor System ◽  
Exhaust Pipe ◽  
Silicon Photomultipliers ◽  
Laser Induced Incandescence ◽  
True Source

To realize an actual in-situ Laser-Induced Incandescence (LII) sensor system for measurements in an exhaust pipe of a combustion engine, suitable components for such an application were chosen, integrated in a first prototype and tested. Key components for the proposed LII system are a super-compact high-power DPSS laser (CTR HiPoLas®) as excitation source, fast KETEK silicon photomultipliers (SiPM) as detectors and a specially designed optical measurement setup. Using a defined aerosol from a soot generator (Jing 5201 miniCAST), signals were collected at different laser energies and soot concentrations. By comparing the recorded behaviour with the literature, the incandescence effect could be reliably identified as the true source of the signal. Further long-term tests at an AVL engine testbed were performed.

A new nonscanning confocal microscopy module for functional voltage-sensitive dye and Ca2+ imaging of neuronal circuit activity

2013 ◽  
Vol 110 (2) ◽  
pp. 553-561 ◽  
Author(s):  
Takashi Tominaga ◽  
Yoko Tominaga
Keyword(s):  
Confocal Microscopy ◽  
Functional Imaging ◽  
Signal To Noise Ratio ◽  
Hippocampal Slices ◽  
Oxide Semiconductor ◽  
High Signal ◽  
High Temporal Resolution ◽  
Fluorescence Signal ◽  
Voltage Sensitive Dye ◽  
Excitation Light

Recent advances in fluorescent confocal microscopy and voltage-sensitive and Ca2+ dyes have vastly improved our ability to image neuronal circuits. However, existing confocal systems are not fast enough or too noisy for many live-cell functional imaging studies. Here, we describe and demonstrate the function of a novel, nonscanning confocal microscopy module. The optics, which are designed to fit the standard camera port of the Olympus BX51WI epifluorescent microscope, achieve a high signal-to-noise ratio (SNR) at high temporal resolution, making this configuration ideal for functional imaging of neuronal activities such as the voltage-sensitive dye (VSD) imaging. The optics employ fixed 100- × 100-pinhole arrays at the back focal plane (optical conjugation plane), above the tube lens of a usual upright microscope. The excitation light travels through these pinholes, and the fluorescence signal, emitted from subject, passes through corresponding pinholes before exciting the photodiodes of the imager: a 100- × 100-pixel metal-oxide semiconductor (MOS)-type pixel imager with each pixel corresponding to a single 100- × 100-μm photodiode. This design eliminated the need for a scanning device; therefore, acquisition rate of the imager (maximum rate of 10 kHz) is the only factor limiting acquisition speed. We tested the application of the system for VSD and Ca2+ imaging of evoked neuronal responses on electrical stimuli in rat hippocampal slices. The results indicate that, at least for these applications, the new microscope maintains a high SNR at image acquisition rates of ≤0.3 ms per frame.

Augmentation of the step-by-step Energy-Scanning EXAFS beamline BL-09 to continuous-scan EXAFS mode at INDUS-2 SRS

2016 ◽  
Vol 23 (6) ◽  
pp. 1518-1525 ◽  
Author(s):  
Ashwini Kumar Poswal ◽  
Ankur Agrawal ◽  
Himanshu Kumar Poswal ◽  
Dibyendu Bhattacharyya ◽  
Shambhu Nath Jha ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Energy Calibration ◽  
Acquisition Time ◽  
High Signal ◽  
Signal To Noise ◽  
Double Crystal ◽  
Time Resolved ◽  
Synchrotron Source ◽  
Double Crystal Monochromator

An innovative scheme to carry out continuous-scan X-ray absorption spectroscopy (XAS) measurements similar to quick-EXAFS mode at the Energy-Scanning EXAFS beamline BL-09 at INDUS-2 synchrotron source (Indore, India), which is generally operated in step-by-step scanning mode, is presented. The continuous XAS mode has been implemented by adopting a continuous-scan scheme of the double-crystal monochromator and on-the-fly measurement of incident and transmitted intensities. This enabled a high signal-to-noise ratio to be maintained and the acquisition time was reduced to a few seconds from tens of minutes or hours. The quality of the spectra (signal-to-noise level, resolution and energy calibration) was checked by measuring and analysing XAS spectra of standard metal foils. To demonstrate the energy range covered in a single scan, a continuous-mode XAS spectrum of copper nickel alloy covering both Cu and NiK-edges was recorded. The implementation of continuous-scan XAS mode at BL-09 would expand the use of this beamline inin situtime-resolved XAS studies of various important systems of current technological importance. The feasibility of employing this mode of measurement for time-resolved probing of reaction kinetics has been demonstrated byin situXAS measurement on the growth of Ag nanoparticles from a solution phase.

scholarly journals P2X-GCaMPs as versatile tools for imaging extracellular ATP signaling

2020 ◽  
Author(s):  
Matthias Ollivier ◽  
Juline Beudez ◽  
Nathalie Linck ◽  
Thomas Grutter ◽  
Vincent Compan ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Atp Release ◽  
Cell Types ◽  
Extracellular Atp ◽  
P2x Receptor ◽  
High Signal ◽  
Calcium Sensors ◽  
Extracellular Signaling

AbstractAdenosine 5’ triphosphate (ATP) is an extracellular signaling molecule involved in numerous physiological and pathological processes. Yet, in situ characterization of the spatiotemporal dynamic of extracellular ATP is still challenging due to the lack of sensor with appropriate specificity, sensitivity and kinetics. Here we report the development of biosensors based on the fusion of cation permeable ATP receptors (P2X) to genetically encoded calcium sensors (GECI). By combining the features of P2X receptors with the high signal to noise ratio of GECIs, we generated ultrasensitive green and red fluorescent sniffers that detect nanomolar ATP concentrations in situ and also enable the tracking of P2X receptor activity. We provide the proof of concept that these sensors can dynamically track ATP release evoked by neuronal depolarization or by extracellular hypotonicity. Targeting these P2X-based biosensors to diverse cell types should advance our knowledge of extracellular ATP dynamics in vivo.

High frequency of in situ hybridization on thin plastic sections of human placenta with a cDNA probe for beta hCG.

1989 ◽  
Vol 37 (8) ◽  
pp. 1193-1196 ◽  
Author(s):  
M Wide ◽  
H Persson ◽  
S Gunnarsson ◽  
L Wide ◽  
L Seifi
Keyword(s):  
In Situ Hybridization ◽  
Human Placenta ◽  
Signal To Noise Ratio ◽  
Cdna Probe ◽  
Acrylic Resin ◽  
Weak Acid ◽  
High Signal ◽  
En Bloc ◽  
Beta Hcg

We describe two different techniques with plastic embedding in in situ hybridization histochemistry (ISHH). Their applicability was demonstrated by use of human placenta of the tenth gestational week and a tritium-labeled cDNA probe for the beta-subunit of hCG. In the first method, ISHH was performed on whole pieces of tissue (en bloc ISHH) pretreated with a weak acid solution, embedded in methacrylate, and sectioned at 3 microns for autoradiography. In the second technique, en bloc ISHH was carried out on tissue pre-treated with the weak acid and thereafter with detergent to further facilitate probe penetration. An acrylic resin was used for embedding, and section thickness was reduced to 1 microns. With both techniques, beta hCG cDNA/mRNA hybrids were localized exclusively to the syncytiotrophoblast (ST), in agreement with a previous study using sections of frozen placentas for hybridization to the same probe. However, owing to the higher resolution of the plastic sections the reliability of this localization was greatly increased. The number of autoradiographic grains over the acrylic resin 1-microns sections was found to be considerably higher than that over the methacrylate 3-microns sections. This study showed that treatment of tissue with detergent before en bloc ISHH, with subsequent embedding in acrylic resin and sectioning at 1 microns, gives high resolution in combination with a high signal-to-noise ratio after autoradiography. As the acrylic resin permits cutting of ultrathin sections, the results suggest that the technique may become useful for ISHH studies at the subcellular level.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

Application of Novel Low Current OBIRCH Amplifier and Nanoprobing to Identify Subtle Leakages in Advanced Node Technologies

2018 ◽  
Author(s):  
Satish Kodali ◽  
Liangshan Chen ◽  
Yuting Wei ◽  
Tanya Schaeffer ◽  
Chong Khiam Oh
Keyword(s):  
Signal To Noise Ratio ◽  
Semiconductor Industry ◽  
Fault Isolation ◽  
Ring Oscillator ◽  
High Signal ◽  
The Novel ◽  
Resistance Change ◽  
Three Samples ◽  
Relative Threshold ◽  
First Time

Abstract Optical beam induced resistance change (OBIRCH) is a very well-adapted technique for static fault isolation in the semiconductor industry. Novel low current OBIRCH amplifier is used to facilitate safe test condition requirements for advanced nodes. This paper shows the differences between the earlier and novel generation OBIRCH amplifiers. Ring oscillator high standby leakage samples are analyzed using the novel generation amplifier. High signal to noise ratio at applied low bias and current levels on device under test are shown on various samples. Further, a metric to demonstrate the SNR to device performance is also discussed. OBIRCH analysis is performed on all the three samples for nanoprobing of, and physical characterization on, the leakage. The resulting spots were calibrated and classified. It is noted that the calibration metric can be successfully used for the first time to estimate the relative threshold voltage of individual transistors in advanced process nodes.

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