Novel Method For Simultaneous Measurement Research Articles

Simultaneous Measurement of Temperature and Pressure Based on Forward Brillouin Scattering in Double-Coated Optical Fiber

A novel method for simultaneous measurement of temperature and pressure based on forward Brillouin scattering (FBS) in double-coated optical fiber is proposed. A new phenomenon, which is the linear relationship between frequency shift of the FBS spectra induced by radial acoustic modes and pressure surrounding the sensing fiber, is theoretically analyzed and experimentally verified. Another new interesting feature is observed that the frequency shift-pressure coefficients of different radial acoustic modes are different. Based on the phenomena that different radial acoustic modes have different frequency shift-temperature and frequency shift-pressure coefficients, we propose a brand-new method to achieve the simultaneous measurement of temperature and pressure by using the frequency shift information of two FBS scattering peaks. In a proof-of-concept experiment, a double-coated single-mode fiber is used as the sensing fiber, and the temperature and pressure measurement errors are 0.13 °C and 0.05 MPa, respectively. The proposed method is expected to become a simple, accurate, durable and stable sensing method for simultaneously measuring temperature and pressure, which has great potential in many practical applications.

Single Channel Instrument for Simultaneous Rotation Speed and Vibration Measurement Based on Self-Mixing Speckle Interference

In this paper, a novel method for simultaneous measurement of rotation speed and vibration based on self-mixing speckle interference (SMSI) has been demonstrated. In view of the autocorrelation characteristic of SMSI, the time delay of laser incident during one rotation period is determined, and the rotation speed of the object is calculated according to the mathematical relationship. At the same time, the signal square-wave conversion and the global maximum fringe-counting method are proposed to measure the vibration displacement subject to the rotation. The theory and signal processing means are introduced in detail, and a series of experiments employing computer disk at different positions with various rotation speeds indicate that the proposed method achieves a simple, efficient, and accurate multi-parameter measurement.

Comparison of methods for nitrous oxide emission estimation in full-scale activated sludge.

Nitrous oxide (N2O) gas transfer was studied in a full-scale process to correlate liquid phase N2O concentrations with gas phase N2O emissions and compare methods of determining the volumetric mass transfer coefficient, KLa. Off-gas and liquid phase monitoring were conducted at the Viikinmäki wastewater treatment plant (WWTP) over a two-week period using a novel method for simultaneous measurement of dissolved and off-gas N2O and O2 from the same location. KLa was calculated with three methods: empirically, based on aeration superficial velocity, from experimentally determined O2 KLa, and using a static value of best fit. The findings of this study indicated trends in local emitted N2O consistently matched trends in local dissolved N2O, but the magnitude of N2O emissions could not be accurately estimated without correction. After applying a static correction factor, the O2 method, using experimentally determined O2 KLa, provided the best N2O emission estimation over the data collection period. N2O emissions estimated using the O2 method had a root mean square error (RMSE) of 70.5 compared against measured concentrations ranging from 3 to 1,913 ppm and a maximum 28% error. The KLa value, and therefore the method of KLa determination, had a significant impact on estimated emissions.

A novel method for simultaneous measurement of thickness, refractive index, bow, and warp of a large silicon wafer using a spectral-domain interferometer

In this study, an optical system for simultaneous measurement of physical thickness, group refractive index, bow, and warp of a large silicon wafer is first proposed based on a reflection-type spectral-domain interferometer. Such key parameters are determined by combining four different optical path differences (OPDs) measured at each sampling point throughout two-axis sample scanning within area of 250 mm by 250 mm. To overcome the measurement limitations by the deflection of a free, unclamped large-sized wafer, two OPDs representing the surface profiles of both sides are utilized to facilitate the thickness and refractive index measurements insensitive to sample inclination. For verification of the proposed method, a 300 mm diameter silicon wafer with nominal thickness of 775 μm was used as a test sample. For measuring the bow and warp with gravity effect compensation, a silicon wafer was measured once again after turning over. Through theoretical analysis on the changes of OPDs with the wafer tilted based on the measured surface profiles, it was verified that the effect of wafer bending on thickness and refractive index measurements can be ignored. The measurement uncertainties (k = 1) of physical thickness, group refractive index, bow, and warp were evaluated to be approximately 0.692 μm, 0.003, 0.416 μm, and 0.589 μm, respectively.

A novel method for simultaneous measurement of temperature and strain based on EFPI/FBG

A modified intensity demodulation method for fiber optic Fabry–Perot cavity and fiber Bragg grating combined sensing system is proposed, through which the cross-sensing error can be reduced effectively and high sensing speed can be realized at the same time. The system is based on an Extrinsic Fabry–Perot Interferometer for strain sensing, and a fiber Bragg grating for temperature sensing. Three-wavelength digital phase demodulation method and passive linear filtering demodulation method are adopted for the demodulation of F–P cavity length and fiber Bragg grating central wavelength, respectively. Meanwhile temperature varied from 25 °C to 105 °C under constant pressure, the demodulation accuracy of strain after correction is ±0.6με, which is improved by 2 times than the direct demodulation result. The demodulation accuracy of temperature is 1.4 °C after correction, with pressure ranging from 0 to 10 MPa at constant temperature. Temperature demodulation error is decreased to 1/3 of its original value. Strain sensing accuracy after correction was ±1με. Experimental studies show that the proposed sensing system has a more compact size and higher measurement accuracy than the previous ones.

A novel method for the measurement of half-lives and decay branching ratios of exotic nuclei

.A novel method for simultaneous measurement of masses, Q-values, isomer excitation energies, half-lives and decay branching ratios of exotic nuclei has been demonstrated. The method includes first use of a stopping cell as an ion trap, combining storage of mother and daughter nuclides for variable durations in a cryogenic stopping cell (CSC), and afterwards the identification and counting of them by a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). We utilized our method to record the decay and growth of the 216Po and 212Pb isotopes (alpha decay) and of the 119m2Sb isomer (t_{1/2} = 850pm 90 ms) and 119gSb isotope (isomer transition), obtaining half-lives consistent with literature values. The amount of non-nuclear-decay losses in the CSC up to sim 10 s is negligible, which exhibits its extraordinary cleanliness. For 119Sb isotopes, we present the first direct measurements of the mass of its ground state, and the excitation energy and decay branching ratios of its second isomeric state (119m2Sb). This resolves discrepancies in previous excitation energy data, and is the first direct evidence that the 119m2Sb isomer decays dominantly via gamma emission. These results pave the way for the measurement of branching ratios of exotic nuclei.

Simultaneous measurement of temperature and strain using a phase-shifted fiber Bragg grating inscribed by femtosecond laser

A novel method for simultaneous measurement of temperature and strain using a single phase-shifted fiber Bragg grating (PS-FBG) is proposed. The PS-FBG is produced by exposing the fusion-spliced fiber with a femtosecond laser and uniform phase mask. Due to the non-uniform structure and strain distribution in the fusion-spliced region, the phase-shift changes with different responses during increases to the temperature and strain; by measuring the central wavelengths and the loss difference of two transmission dips, temperature and strain can be determined simultaneously. The resolutions of this particular sensor in measuring temperature and strain are estimated to be ±1.5 °C and ±12.2 µε in a range from −50 °C to 150 °C and from 0 µε to 2070 µε.

Simultaneous Laser Doppler Velocimetry and stand-off Raman spectroscopy as a novel tool to assess flow characteristics of process streams

Flow characteristics of process streams are important in industrial chemical plants. Online measurement of physical and chemical properties of such streams like velocity, turbulence, chemical composition, and concentration, plays a key role in adjustment and optimization of industrial processes. In transient processes with steep changes in the concentration and velocity (e.g. mixing of fluid with different viscosities or multiphase flows) it is important to monitor process parameters at the same time and position to be able to iterpret them correctly. In this work, a novel method for simultaneous measurement of velocity, composition, and concentration relying on two well-known methods, Laser Doppler Velocimetry (LDV) and Raman spectroscopy is presented and tested. Both techniques were combined using the same laser as light source, thus making sure sampling from exactly the same position at the same time is achieved. Experiments on mixing of water and ethanol streams in a custom-built T-junction geometry were performed using LDV to obtain velocity and Raman spectroscopy to measure concentration using the suggested method. Results are compared against Computational Fluid Dynamics (CFD) simulations using models for mixing of miscible, multi-species liquids at different flow regimes. CFD predicts turbulent diffusion to be the dominant phenomena in mixing in the T-junction since the turbulent diffusion coefficient (∼0.02 m2/s) is much higher than the molecular diffusion coefficient (∼10−8 m2/s). A mean deviation of 8% between model and experiment for velocity and 10% for concentration evaluation was observed, which suggests the feasibility of this technique for simultaneous monitoring of process streams.

Line-Field Swept-Source Interferometer for Simultaneous Measurement of Thickness and Refractive Index Distribution

We present a novel method for simultaneous measurement of the thickness and refractive index distribution of a transparent specimen by a line-field swept-source interferometer. In this study, by illuminating with the line-field beam instead of the point-focused beam, multiple interferences along the line-field distribution are measured simultaneously by using a combination of a novel swept source of 800-nm central region and a Si-based 1024-pixel charge-coupled device (CCD) detector. When the transparent specimen has an uneven thickness or nonuniform refractive index, the whole distribution of these two parameters can be also simultaneously measured over the illuminated region with a one-step comparison process. Using four types of transparent specimens, the thickness and refractive index distribution of each sample and a group sample paired with two specimens are accurately measured during the single wavelength scanning time of 27 ms by using the swept source with a 36-Hz sweeping rate and the CCD detector with a 36-kHz line rate.

Strain and high-temperature discrimination using a Type II fiber Bragg grating and a miniature fiber Fabry-Perot interferometer.

A novel method for simultaneous measurement of strain and high temperature using a Type II fiber Bragg grating (FBG) and a miniature fiber Fabry-Perot interferometer (MFFPI) is proposed. The MFFPI is produced by fusion splicing a short section of quartz capillary tube with two single-mode fibers, and then it is exposed by a focused femtosecond laser and a phase mask to inscribe a Type II FBG nearby. The reflection spectrum of this sensor is the superposition of the reflection spectrum of the FBG and the interference fringe of the MFFPI. This sensor shows perfect high-temperature and strain responses. Because of the different responses to the uniform variations of strain and temperature, by measuring the reflection peak of FBG and one of the interference dips of the MFFPI, strain and temperature can be simultaneously determined. The resolutions of this particular sensor in measuring strain and temperature are estimated to be ±8.4 μϵ and ±3.3°C, respectively, in the range from 0 to 1122 μϵ and from 23°C to 600°C.

A novel method for simultaneous measurement of concentration and enrichment of NO synthesis-specific amino acids in human plasma using stable isotopes and LC/MS ion trap analysis

Stable isotope studies offer the opportunity to study the in-depth metabolic pathway of glutamine, citrulline, and arginine amino acids involved in NO synthesis. The use of multiple stable isotopes can be used to elucidate the exact transformation of glutamine to citrulline and arginine de novo synthesis. This novel method provides a purification step using cation exchange resin in combination with a rapid and easy derivatization procedure for a precise and robust measurement of the concentration and isotopic enrichments of NO synthesis-specific amino acids using a liquid chromatography mass spectrometry (LC/MS) ion trap system with high sensitivity and selectivity. The ethyl chloroformate derivatization procedure is beneficial in terms of robustness, velocity, simplicity, and derivative stability. In addition, the ethyl chloroformate derivatization can be performed at room temperature in an aqueous environment without incubation and the isolation of the derivatives from the reaction mixture also serves as a purification step. The concentration and enrichment of NO synthesis-specific amino acids as well as phenylalanine and tyrosine to determine protein turnover, were measured with good inter-day precision for the concentration (<7.4%) and enrichment (<12.7%) in plasma samples at low and high levels. The low limit of quantification was 0.2μmol/L for most of the amino acids and the purification method showed to have good recoveries between 78% and 98%. No ion-suppression was observed by post-column infusion experiments. In order to develop new nutritional strategies, this novel method can be used to support the elucidation of the effect of administration of specific supplements on the glutamine-citrulline-arginine pathway by using stable isotope studies.

Novel method for simultaneous measurement of film thickness and mass fraction of urea–water solution

Quantitative knowledge of the film thickness and mass fraction of the urea-water solution is very crucial in many practical applications. Film thickness or mass fraction can only be determined individually by conventional measurement techniques. We develop a novel measurement method to measure the film thickness and mass fraction of urea-water solution simultaneously. The absorption coefficients of urea-water solution (5-50 wt%) are measured, a pair of optimized wavelengths is then chosen to achieve high measurement sensitivity. Cross validation is also performed and uncertainties of the technique are smaller than 0.68% for thickness measurements and 1.86% for mass fractions.

Simultaneous measurement of refractive index and temperature using thinned fiber based Mach–Zehnder interferometer

A novel method for simultaneous measurement of refractive index and temperature based on a small core and cladding diameters thinned fiber Mach–Zehnder interferometer (MZI) using singlemode-multimode-thinned-multimode-singlemode (SMTMS) fiber structure is proposed. Experiments indicate that the selected two interference orders have sensitivities of −16.1936nm/RIU and 0.0534nm/°C, and −23.0473nm/RIU and 0.0575nm/°C, respectively, among RI range from 1.3325–1.3720 and temperature range from 22°C–82°C. We can thus use the coefficient matrix of these two peaks to simultaneously determine the surrounding refractive index and temperature. The fabrication is easy, safe and cost effective, includes only the fusion splicing, making the device properly attractive for practical sensor applications.

A novel method for simultaneous measurement of doped optical fiber parameters

Simultaneous measurement technique of evaluating the doped optical fibers (DOF) parameters is a suitable scheme for DOF production industries. In this paper, we introduce a novel technique to characterize simultaneously the main parameters of DOF such as absorption and emission cross-sections (ACS, ECS), background loss coefficient (BLC), and low dopant concentration using the gain equation of DOFs. We used this new method to determine the ACS, ECS, BLC in a standard sample of Al-P-Erbium doped optical fiber. The results have been analyzed and compared with other reports.

Simultaneously Measuring Lateral and Vertical Forces with Accurate Gap Control for Clarifying Lubrication Phenomena at Nanometer Gap

A novel method for simultaneous measurement of vertical and lateral forces with high sensitivity and accurate gap control is presented. It combines a double-ended tuning fork resonator for vertical force measurement with an optical fiber probe for lateral force measurement. High force sensitivity of several tens of nano Newons with accurate gap control of less than 1 nm was successfully attained. Simultaneous measurement using this novel method revealed that viscoelasticity increased with decrease of the sliding gap. Moreover, the method first revealed that the lubricant pressure generated by the wedge effect can increase due to the confinement at small gaps, even if the lubricant pressure is so low that the viscosity rise due to the pressure is much small. This method is expected to be useful for clarifying the lubrication phenomena at nanometer sliding gaps, which are not yet fully understood due to the difficulty of measurement.

Simultaneous Measurement of Longitudinal and Transverse Waves Velocities Employing Spherically Focused Acoustic Transducer

Scanning acoustic microscopy (SAM) has been applied successfully to measure leaky surface wave(LSAW) velocity from V(z) curve for material characterization. Besides LSAW, SAM produces a variety of wave modes in the material propagating with different phase speeds and features, one of which is the mode-converted ultrasound. In this paper, a novel method for simultaneous measurement of longitudinal and transverse acoustic wave velocities using the mode-converted ultrasound is developed and studied at SAM. Each ultrasound arriving at the acoustic lens with different speed and phase (or time-of-flight (TOF)) is measured by the defocused transducer to calculate longitudinal and transverse wave velocities. Simple mathematical ray analysis for the mode conversion is conducted to determine the relationship of acoustic velocities with TOF of the waves in plate. Experimental results for metals and glass show that the longitudinal and transverse wave velocities measured by the proposed method are as accurate as maximum 3% in error.

P‐32: Simultaneous Measurements of Thickness of Filled Cholesteric LC Cell and the Average Refractive Index

AbstractA novel method for simultaneous measurement of an average refractive index of the cholesteric LC cell and a cell gap of the filled LC cell has been proposed. It is based on spectrum analysis of light mirror reflected from a LC cell at different angles. This method can be applied to other types of liquid crystal cells and easily implemented in commercial instruments.

A novel method for simultaneous measurement of current and voltage using one low-birefringence fiber

A novel method for simultaneous measurement of current and voltage employing a single monomode low-birefringence (Lo-Bi) fiber is described. This uses the Faraday effect for detection of current and the Kerr effect for detection of voltage. The waveform of the output light intensity due to the Kerr effect has been detected and the Kerr constant was measured as 5.4×10 −16 m/V −2 at 25°C. Theoretical analysis shows that the current component can be measured free from the influence of the voltage component and the two components can be easily separated.