Technique For Simultaneous Measurement Research Articles

Upgrade of DIII-D radial interferometer-polarimeter for large bandwidth, low noise, and toroidal mode number measurements.

Near ion-cyclotron frequency (fci) fluctuations, such as those originating from Global and Compressional Alfvén Eigenmodes (GAEs/CAEs), are expected to be present in future fusion reactors but are not well understood due to the limited availability of core measurements in present-day tokamaks. The measurement bandwidth of the Radial Interferometer-Polarimeter (RIP) diagnostic has been upgraded from 1 to 5MHz to detect these fluctuations in DIII-D. RIP adopts the three-wave technique for simultaneous polarimetric and interferometric measurements. Solid-state microwave sources operating at 650GHz are used as probe beams and provide 5MHz bandwidth for both polarimetric and interferometric measurements. Bandwidths of related hardware, including mixer amplifier, signal cable, and digital phase demodulator, are increased correspondingly. Measurement noise is minimized by reducing the time delay between reference and probe signals to nanosecond level and employing correlation-based techniques. Using the upgraded diagnostic, CAE/GAE-like bursting fluctuations are observed in neutral-beam heated plasmas with toroidal magnetic field Bφ ≈ 1 T. Current upgrades being undertaken would enable the evaluation of toroidal mode number for these modes. This work opens the possibility of better understanding near ion-cyclotron frequency fluctuations in fusion relevant plasmas.

Laser Ultrasonic Technique for Simultaneous Measurement of Thickness, Slope, and Wave Velocities for Slope Plate in the Thermoelastic Regime

Laser Ultrasonic Technique for Simultaneous Measurement of Thickness, Slope, and Wave Velocities for Slope Plate in the Thermoelastic Regime

Completely noninvasive multi-analyte monitoring system for cell culture processes

Although online monitoring of dissolved O2, pH, and dissolved CO2 is critical in bioprocesses, nearly all existing technologies require some level of direct contact with the cell culture environment, posing risks of contamination. This study addresses the need for an accurate, and completely noninvasive technique for simultaneous measurement of these analytes. A “non-contact” technique for simultaneous monitoring of dissolved O2, pH, and dissolved CO2 was developed. Instead of direct contact with the culture media, the measurements were made through permeable membranes via either a sampling port in the culture vessel wall or a flow cell. The efficacy of the “non-contact” technique was validated in Escherichia coli (E.coli), Chinese hamster ovary (CHO) culture processes, and dynamic environments created by sparging gases in cell culture medium. The measurements obtained through the developed techniques were comparable to those obtained through control methods. The noninvasive monitoring system can offer accurate, and contamination-minimized monitoring of critical process parameters including dissolved O2, pH, and dissolved CO2. These advancements will enhance the control and optimization of cell culture processes, promising improved cell culture performance.

Dichotomous dynamics of magnetic monopole fluids

A recent advance in the study of emergent magnetic monopoles was the discovery that monopole motion is restricted to dynamical fractal trajectories [J. N. Hallén et al., Science 378, 1218 (2022)], thus explaining the characteristics of magnetic monopole noise spectra [R. Dusad et al., Nature 571, 234 (2019); A. M. Samarakoon et al., Proc. Natl. Acad. Sci. U.S.A. 119, e2117453119 (2022)]. Here, we apply this novel theory to explore the dynamics of field-driven monopole currents, finding them composed of two quite distinct transport processes: initially swift fractal rearrangements of local monopole configurations followed by conventional monopole diffusion. This theory also predicts a characteristic frequency dependence of the dissipative loss angle for AC field-driven currents. To explore these novel perspectives on monopole transport, we introduce simultaneous monopole current control and measurement techniques using SQUID-based monopole current sensors. For the canonical material Dy2Ti2O7, we measure [Formula: see text], the time dependence of magnetic flux threading the sample when a net monopole current [Formula: see text] is generated by applying an external magnetic field [Formula: see text] These experiments find a sharp dichotomy of monopole currents, separated by their distinct relaxation time constants before and after t ~[Formula: see text] from monopole current initiation. Application of sinusoidal magnetic fields [Formula: see text] generates oscillating monopole currents whose loss angle [Formula: see text] exhibits a characteristic transition at frequency [Formula: see text] over the same temperature range. Finally, the magnetic noise power is also dichotomic, diminishing sharply after t ~[Formula: see text]. This complex phenomenology represents an unprecedented form of dynamical heterogeneity generated by the interplay of fractionalization and local spin configurational symmetry.

Novel surface wave technique for moderate-pressure plasma measurements

Most in situ plasma diagnostics are only reliable for low-pressure systems, e.g., systems where the collision frequency, νen, is small compared to the plasma frequency, ωpe. In this article, we describe a novel diagnostic technique for simultaneous measurement of the plasma density, ne; electron temperature, Te; and νen in systems in which νen approaches ωpe. We illustrate the operational setup of our probe system along with an analytical framework for ascertaining ne, Te, and νen. Furthermore, we show experimental results from argon capacitively coupled plasma operating in the 0.5–1 Torr pressure range.

Two-phase hydrodynamics and aerosol mass transfer characterization in pool scrubbing: A simultaneous measurement technique

The bubbling of particle-contaminated gases through a liquid pool, called aerosol scrubbing, is a reliable, robust, and efficient collection technique to retain harmful aerosols from industrial processes or hazardous incidents. In this multiphase mass transfer phenomenon, the two-phase flow mechanics strongly influences the particle transport from the gas in the bubble to the surrounding liquid. The numerical and experimental studies have primarily focused on ideal flows and separate test effects. Here we developed a new experimental approach to assess the aerosol mass transfer and two-phase flow hydrodynamics simultaneously via tomographic conductivity measurements using a Wire-mesh sensor and an electrolytic aerosol scrubbed in a prototypical water column. The bubble phenomenology and size distribution can be effectively captured, and the aerosol deposition coefficient can be determined by measuring the electrolytic concentration increase in the liquid phase. Our integral results of the total retained mass in the column are compared with the aerosol mass concentration determined with filter measurements showing good agreement. We study the influence of the position and presence of the wire-mesh sensor on the results. The location has minor effects due to the high mixing level of the liquid phase. It is observed that the wire-mesh sensor could increase the mass transfer by not more than 5–10 %. We finally compare our mass transfer results with algebraic model predictions and suggest improvements to detect and study the mass transfer at the local bubble scale.

Confirming Silent Translocation through Nanopores with Simultaneous Single-Molecule Fluorescence and Single-Channel Electrical Recordings.

Most of what is known concerning the luminal passage of materials through nanopores arises from electrical measurements. Whether nanopores are biological, solid-state, synthetic, hybrid, glass-capillary-based, or protein ion channels in cells and tissues, characteristic signatures embedded in the flow of ionic current are foundational to understanding functional behavior. In contrast, this work describes passage through a nanopore that occurs without producing an electrical signature. We refer to the phenomenon as "silent translocation." By definition, silent translocations are invisible to the standard tools of electrophysiology and fundamentally require a simultaneous ancillary measurement technique for positive identification. As a result, this phenomenon has been largely unexplored in the literature. Here, we report on a derivative of Cyanine 5 (sCy5a) that passes through the α-hemolysin (αHL) nanopore silently. Simultaneously acquired single-molecule fluorescence and single-channel electrical recordings from bilayers formed over a closed microcavity demonstrate that translocation does indeed take place, albeit infrequently. We report observations of silent translocation as a function of time, dye concentration, and nanopore population in the bilayer. Lastly, measurement of the translocation rate as a function of applied potential permits estimation of an effective energy barrier for transport through the pore as well as the effective charge on the dye, all in the absence of an information-containing electrical signature.

Simultaneous measurement of refractive index and dispersion using optical coherence tomography for restoration of transparent works of art

We describe a novel in situ non-invasive and non-contact technique for simultaneous measurement of refractive index and dispersion of transparent solid materials using optical coherence tomography (OCT). The technique requires multi-angle OCT imaging. It gives typical precision of 0.02 for the refractive index and 0.03 mum^{-1} for dispersion. The method can be applied to the restoration of modern sculptures made from plastics where it is important to have precise measurement of the refractive index of an object using a non-contact method, so that a resin-based adhesive with a matching refractive index could be found to restore a scratched or broken transparent works of art.

Development of a multi-needle fiberoptic Raman spectroscopy technique for simultaneous multi-site deep tissue Raman measurements in the brain.

We report on the development of a multi-needle fiberoptic Raman spectroscopy (MNF-RS) technique for simultaneous multi-site deep Raman measurements in brain tissue. The multi-needle fiberoptic Raman probe is designed and fabricated using a number of 100 µm core diameter, aluminum-coated fibers under a coaxial laser excitation and Raman collection scheme, enabling simultaneous collection of deep tissue Raman spectra from a number of tissue sites. We have also developed a Raman retrieval algorithm based on the transformation matrix of each individual needle fiber probe projected to different pixels of a charge-coupled device (CCD) for recovering the tissue Raman spectra collected by each needle fiber probe, allowing simultaneous multi-channel detection by a single Raman spectrometer. High-quality tissue Raman spectra of different tissue types (e.g., muscle, fat, gray matter, and white matter in porcine brain) can be acquired in both the fingerprint (900-1800 cm-1) and high-wavenumber (2800-3300 cm-1) regions within sub-second times using the MNF-RS technique. We also demonstrate that by advancing the multi-needle fiberoptic Raman probe into deep porcine brain, tissue Raman spectra can be acquired simultaneously from different brain regions (e.g., cortex, thalamus, midbrain, and cerebellum). The significant biochemical differences across different brain tissues can also be distinguished, suggesting the promising potential of the MNF-RS technique for label-free neuroscience study at the molecular level.

Twin background subtraction technique: A novel infrared technique for simultaneous thickness and temperature measurements of micro films

The study proposes a novel non-intrusive infrared technique to measure simultaneously the thickness and temperature of a thin layer that is semi-transparent to infrared radiation. The measurement method has been called Twin Background Subtraction technique. The technique simultaneously exploits the mid-wave IR emission from the film to be measured and the radiation attenuation by the same film of the emission coming from two backgrounds at different constant temperatures. This study discusses the method theoretically and experimentally, focusing on the uncertainties and the dependence on different parameters of the set-up and fluid physical properties.The fluid adopted for the film is water, and various tests have been carried out by changing its temperature between 15 and 50 °C and its thickness from 0 to 500 µm. The TBS technique was proven to be of interest for studying micro to mini films both from a qualitative and quantitative point of view for water films ranging between 10 µm and 350 µm.

Unraveling the failure mechanism of wire arc additive manufactured low carbon steel under tensile and high cycle fatigue loading

Wire arc additive manufacturing (WAAM) is one of the common additive manufacturing processes for efficiently building large components due to its high deposition rate and higher catchment efficiency with an easy and relatively simpler arrangement. However, WAAM components often observe defects that adversely affect some mechanical properties. The present work employs a two-camera digital image correlation (DIC)-based technique for simultaneous strain measurements on two mutually orthogonal surfaces to capture the strain accumulation due to defects and subsequent failure behavior under uniaxial tensile loading of WAAM deposited ER70S-6 low carbon steel samples. The elastic cyclic loading tests are also performed at different stress amplitudes, and their fracture surfaces are analyzed with scanning electron microscopy. Due to the weak interlayer consolidation, multiple delaminations and strain accumulation sites are observed. Propagation of delamination contributed towards the failure, and dimples as well as intergranular fractures are observed on failure surfaces. Premature failure with a reduced number of cycles to failure is observed during high cycle fatigue tests due to catastrophic fast failure in the neighborhood of the internal defects. While the fatigue crack initiation and propagation are distinctly observed on fracture surfaces, transition regions from fatigue fracture and fast fracture are mostly obscure.

An experimental methodology to study impulsive hydrodynamic loading of air-backed composite plates

Sandwich composites in marine vessels are frequently exposed to impulsive hydrodynamic loading during operation in extreme environments. The response of sandwich composites to impulsive hydrodynamic loading has yet to be fully investigated due to the lack of full-field, simultaneous measurement techniques. Here, we propose an experimental framework for the study of the dynamic response of sandwich composites to hydrodynamic loading. We focus on a fiber-reinforced plate positioned at the air-water interface subjected to impulsive hydrodynamic loading. The interaction between the plate and the water is studied through a combined visualization technique based on particle image velocimetry (PIV) and digital image correlation (DIC). The velocity and pressure fields are quantified through PIV, and, simultaneously, the out-of-plane vibration of the plate is inferred from DIC. Repeated measurements were conducted for a range of hydrodynamic loading conditions. Our experiments unveiled a rich multimodal response that is strongly coupled with the flow physics. This work constitutes a first step toward an experimental understanding of fluid-structure interaction of air-backed sandwich composites.

How to Use Fiber Optic Sensors for Accurate Absolute Measurements - INVITED

The scientific community has been exploring new concepts as a result of the usage of optical fibers as absolute measurement sensors. While cross-sensitivity is a common issue with optical fiber sensors, this issue has been mitigated by simultaneous measurement techniques. But when it comes to absolute measurements, these methods have some limitations. The white light interferometer, which offers a superb solution for a range of applications, especially for absolute temperature measurement, is one of the most often used methods for absolute measurements.

Simultaneous Temperature and Velocity Measurement Technique Based on Hydroxyl Tagging

Simultaneous Temperature and Velocity Measurement Technique Based on Hydroxyl Tagging

Comparison of FWHM and peak power techniques for simultaneous measurement of strain and temperature in FBG sensors

Comparison of FWHM and peak power techniques for simultaneous measurement of strain and temperature in FBG sensors

Adaptive window technique for lifetime-based temperature and velocity simultaneous measurement using thermographic particle tracking velocimetry with a single camera

Adaptive window technique for lifetime-based temperature and velocity simultaneous measurement using thermographic particle tracking velocimetry with a single camera

Design and validation of a low-cost open-source impedance based quartz crystal microbalance for electrochemical research

The quartz crystal microbalance (QCM) measurement technique is utilized in a broad variety of scientific fields and applications, where surface and interfacial processes are relevant. However, the costs of purchasing QCMs is typically high, which has limited its employment in education as well as by scientists in developing countries. In this article, we present an open-source QCM, built on the OpenQCM project, and using an impedance-based measurement technique (QCM-I), which can be built for <200 euro. Our QCM allows for simultaneous monitoring of the frequency change and dissipation, such that both soft and rigid materials can be characterized. In addition, our QCM measurements can be combined with simultaneous electrochemical measurement techniques (EQCM-I). We demonstrate the validity of our system by characterizing the electrodeposition of a rigid metallic film (Cu) and by the electropolymerization of aniline. Finally, we discuss potential improvements to our system.

A simultaneous measurement technique for soot temperature and volume fraction of sooting flames considering self-absorption through hyperspectral imaging

Due to the complex optical properties of sooting flames, the accuracy of flame emission-based measurement techniques depends on an appropriate self-absorption correction strategy. Thus, this paper presents a novel iterative procedure to retrieve the soot temperature and volume fraction of sooting flames along with a self-absorption correction strategy through hyperspectral imaging. Numerical simulations were carried out on suppositional flames to investigate the performance of the proposed technique. Relative errors obtained from the simulations are below 1.5%, indicating a better accuracy can be achieved by the proposed reconstruction technique. A hybrid camera hyperspectral video imaging technique is designed and implemented with the concept of compressed sensing. A significant improvement in flame spectrum acquisition has been observed. Experiments were carried out under ethylene-air diffusion flames to validate the technique. The reconstructed flame soot temperature and volume fraction distributions demonstrated that the proposed hyperspectral video imaging technique improves the soot temperature and volume fraction reconstruction accuracy.

Simultaneous Particle Tracking Velocimetry And Pyrometry Of Spatter Particles Ejected During The Laser Power-Bed Fusion Process Using A Spectral Plenoptic Camera

This paper aims to provide a method for simultaneous 3D particle tracking velocimetry and dual-wavelength pyrometry using a single spectral plenoptic camera for uses in spray and flow diagnostics. The spectral plenoptic camera can capture spatial, angular, and spectral information of light from the scene using a single main lens and sensor. Particle tracking is conducted using the Light-Field Ray Bundling algorithm paired with a four-frame best estimate-enhanced track initialization algorithm to generate 3D high-resolution spatial locations and velocity of particles. Secondly, a dual-wavelength pyrometry method was developed to use particle locations from Light-Field Ray Bundling to find the particle spectra for each wavelength, and then calculate temperature using the spectral intensities. This method achieves 3D particle tracking and temperature measurements using a single lens and sensor, which can be applicable for many different flow measurements. The method was applied to the spatter particle generation caused by the Laser Powder-Bed Fusion process, where spatter particles have been found to be detrimental to the manufactured parts. The calculated speeds of the spatter particles are within the expected range, and the tracks show a complex 3D process. The temperature measurements indicate that the detected particles are in the liquid phase, with temperatures greater than 2000ºC. The simultaneous measurements demonstrate an overall deceleration and cooling of particles during their flight. Therefore, this is a viable technique for simultaneous tracking and temperature measurements.

The Interaction Between In-Cylinder Flow And Flame Propagation In An Optical SI Engine Measured By High-Speed PIV

The relationship between the flow field and flame propagation is essential in determining the dynamics and effects of turbulent flow in an optical SI engine. In this study, the high-speed PIV technique was applied to evaluate the incylinder velocity and turbulence distribution under firing condition. The simultaneous measurement technique of incylinder flow and flame propagation characterized the relationship between flow field and flame propagation in the same cycle. A 500 cc single-cylinder optical engine was used for this experiment. The bore diameter and stroke length were 86 mm and 86 mm respectively, and compression ratio was 10.4. The flame front configuration was extracted from the PIV image based on planar laser tomography method. The strong contrast between the intensity of burned and unburned region in the captured images due to low gas and seed density of the former was utilized to derive this flame front. In order to evaluate the interaction between flame and flow with high resolution, the interrogation area was set to 16 × 16 pixels. This corresponds to 0.75 × 0.75 mm. The spatial filter of 6 mm was used to separate the instantaneous flow velocity into a low frequency component and a high frequency component. The engine speed was 1200 rpm and absolute intake pressure was 60 kPa. The equivalence ratio was stoichiometry condition. The ignition timing were set to 19 deg.BTDC. The characteristic cycles in the same test condition were extracted and discussed. The bulk flow with the large scale as large as the size of the combustion chamber influences the overall shape of the flame propagation, and the state of the flame propagation greatly fluctuates from cycle to cycle. The flame propagates with enhancing the large scale existing tumble flow that exists in earlier crank angle locations. Focusing on the local flame structure, the high-frequency velocity component was strong near the local flame peak and weak near the local flame valley. The flame at the local peak region propagates while pulling the valley region.