Compensation Of Temperature Effects Research Articles

Analysis Model Verification of a Suspension Bridge Exploiting Configuration Survey and Field-Measured Data

The conformity between predicted and actual configurations of a suspension bridge is examined through a field survey with the compensation of temperature effects. The tension in the main cable is estimated from the surveyed configuration utilizing force equilibriums at the cable junction nodes. The measured hanger tensions and rigorous dead load information are also incorporated. The as-built configuration of the bridge shows fairly good agreement with the designed shape. The reproducibility of the dynamic properties is also examined for dominant vertical modes. The only tuning in the connection conditions of bearings produces natural frequencies that are in good agreement with the measured values.

Real-time multi-sensors measurement system with temperature effects compensation for impedance-based structural health monitoring

This article presents a simple and versatile measurement system for structural health monitoring (SHM) based on the electromechanical impedance (EMI) technique. The proposed system allows real-time data acquisition from multiple sensors and includes compensation for temperature effects, eliminating one cause of incorrect diagnoses in structural monitoring. Besides the low cost compared to conventional impedance analyzers, the hardware and the software are simple and easier to implement than other measurement systems that have been recently proposed. Tests were carried out on an aluminum beam under different temperatures and on an aluminum plate with nine PZT (lead zirconate titanate) patches. The experimental results show conclusively that the proposed methodology is efficient and feasible for real-time SHM.

A generalized CMOS-MEMS platform for micromechanical resonators monolithically integrated with circuits

A generalized foundry-oriented CMOS-MEMS platform well suited for integrated micromechanical resonators alongside IC amplifiers has been developed for commercial multi-user purpose and demonstrated with a fast turnaround time of only 3 months and a variety of design flexibilities for resonator applications. With this platform, different configurations of capacitively-transduced resonators monolithically integrated with their amplifier circuits, spanning frequencies from 500 kHz to 14.5 MHz, have been realized with resonator Q's ranging between 700 and 3500. This platform, specifically featured with various configurations of structural materials, multi-dimensional displacements, different arrangements of mechanical boundary conditions, tiny supports of resonators, large transduction areas, well-defined anchors and performance enhancement scaling with IC fabrication technology, offers a variety of flexible design options targeted for sensor, timing reference, and RF applications. In addition, resonators consisting of metal-oxide composite structures fabricated by this platform offer an effective temperature compensation scheme for the first time in CMOS-MEMS resonators, showing TCf six times better than that of resonators merely made by CMOS metals.

Thermal Robustness of Signaling in Bacterial Chemotaxis

Temperature is a global factor that affects the performance of all intracellular networks. Robustness against temperature variations is thus expected to be an essential network property, particularly in organisms without inherent temperature control. Here, we combine experimental analyses with computational modeling to investigate thermal robustness of signaling in chemotaxis of Escherichia coli, a relatively simple and well-established model for systems biology. We show that steady-state and kinetic pathway parameters that are essential for chemotactic performance are indeed temperature-compensated in the entire physiological range. Thermal robustness of steady-state pathway output is ensured at several levels by mutual compensation of temperature effects on activities of individual pathway components. Moreover, the effect of temperature on adaptation kinetics is counterbalanced by preprogrammed temperature dependence of enzyme synthesis and stability to achieve nearly optimal performance at the growth temperature. Similar compensatory mechanisms are expected to ensure thermal robustness in other systems.

Modeling and Adaptive Decoupling of High-Frequency Resistance and Temperature Effects in Carrier-Based Sensorless Control of PM Synchronous Machines

This paper analyzes the effects of the high-frequency resistances in saliency tracking-based sensorless control methods of permanent-magnet synchronous machines (PMSMs). A high-frequency model of the PMSM, including stator high-frequency resistance, is presented. From this model, potential sources of error in the estimated position due to the high-frequency resistances are analyzed, and their compensation by means of an adaptive decoupling mechanism is proposed. This paper also addresses the influence and compensation of temperature effects in carrier-signal-injection-based sensorless techniques.

5.2 GHz variable-gain amplifier and power amplifier driver for WLAN IEEE 802.11a transmitter front-end

A 5.2 GHz variable-gain amplifier (VGA) and a power amplifier (PA) driver are designed for WLAN IEEE 802.11a monolithic RFIC. The VGA and the PA driver are implemented in a 50 GHz 0.35 μm SiGe BiCMOS technology and occupy 1.12 × 1.25 mm2 die area. The VGA with effective temperature compensation is controlled by 5 bits and has a gain range of 34 dB. The PA driver with tuned loads utilizes a differential input, single-ended output topology, and the tuned loads resonate at 5.2 GHz. The maximum overall gain of the VGA and the PA driver is 29 dB with the output third-order intercept point (OIP3) of 11 dBm. The gain drift over the temperature varying from –30 to 85° C converges within ±3 dB. The total current consumption is 45 mA under a 2.85 V power supply.

Temperature effects in ultrasonic Lamb wave structural health monitoring systems

There is a need to better understand the effect of temperature changes on the response of ultrasonic guided-wave pitch-catch systems used for structural health monitoring. A model is proposed to account for all relevant temperature-dependent parameters of a pitch-catch system on an isotropic plate, including the actuator-plate and plate-sensor interactions through shear-lag behavior, the piezoelectric and dielectric permittivity properties of the transducers, and the Lamb wave dispersion properties of the substrate plate. The model is used to predict the S(0) and A(0) response spectra in aluminum plates for the temperature range of -40-+60 degrees C, which accounts for normal aircraft operations. The transducers examined are monolithic PZT-5A [PZT denotes Pb(Zr-Ti)O3] patches and flexible macrofiber composite type P1 patches. The study shows substantial changes in Lamb wave amplitude response caused solely by temperature excursions. It is also shown that, for the transducers considered, the response amplitude changes follow two opposite trends below and above ambient temperature (20 degrees C), respectively. These results can provide a basis for the compensation of temperature effects in guided-wave damage detection systems.

Reliability evaluations for board-level chip-scale packages under coupled power and thermal cycling test conditions

To evaluate conjointly the effects of ambient temperature fluctuation and operation bias on the reliability of board-level electronic packages, a coupled power and thermal cycling test has been proposed. In this study, the sequential thermal–mechanical coupling analysis, which solves in turn the transient temperature field and subsequent thermomechanical deformations, is performed to investigate thermal characteristics along with fatigue reliability of board-level thin-profile fine-pitch ball grid array chip-scale packages under coupled power and thermal cycling test conditions. Effects of different power cycling durations are studied. A pure thermal cycling condition is also examined and compared. Numerical results indicate that, for the coupled power and thermal cycling test, a shorter power cycling duration in general leads to a shorter fatigue life. However, the temperature compensation effect elongates the fatigue life under certain power cycling durations.

Study on compensation of temperature effects on strain measurement in structural health monitoring

Study on compensation of temperature effects on strain measurement in structural health monitoring

수정미소저울 노점센서 제작 및 반응특성 연구

This paper represents development of quartz crystal microbalance (QCM) and usage as a dew point sensor. The temperature of a quartz resonator was controlled precisely from <TEX>$20^{\circ}C$</TEX> to <TEX>$-30^{\circ}C$</TEX> with the ramping rate of <TEX>$0.1^{\circ}C/s$</TEX> by using a custom-made crystal holder housing the quartz resonator associated with a thermoelectric cooler (Peltier cooler), which results in the working range from <TEX>$15.2^{\circ}C$</TEX> to <TEX>$-24.0^{\circ}C$</TEX> based on an accurate holder temperature compensation and temperature effect compensation process. The developed QCM dew point sensor and analysis techniques show very good sensing characteristics at measurement of moist air with the relative humidity from 10 %R.H. to 90 %R.H. generated by a divided-type humidity generator and the dew point temperatures were determined with an accuracy of less than <TEX>${\pm}0.18^{\circ}C$</TEX>, which also showed good agreement with reference values in their error range.

Dielectric behavior of insulating liquids at very low frequency

Dielectric spectroscopy in the wide frequency range of 1 mHz to 1 kHz has been used to study the polarization and conduction phenomena in insulating liquids. The dielectric spectroscopy of mineral oil and ester oil at different conditions, i.e. temperatures and electric fields, has been measured. It came out that at low frequencies, space charge polarization changes the permittivity of insulating liquid and at very low frequencies, the consideration of a RC parallel model for the dielectric behavior of insulating liquids is not adequate. The results indicate that the permittivity of insulating liquid increases with aging duration and therefore it can be used as a diagnosis parameter for insulating liquids. The calculation of the activation energy of the conduction process shows that consideration of single activation energy for compensation of temperature effect on dielectric loss for dielectric spectroscopy in the wide frequency range is not perfect

Adhesion controls bacterial actin polymerization-based movement

As part of its infectious life cycle, the bacterial pathogen Listeria monocytogenes propels itself through the host-cell cytoplasm by triggering the polymerization of host-cell actin near the bacterial surface, harnessing the activity of several cytoskeletal proteins used during actin-based cell crawling. To distinguish among several classes of biophysical models of actin-based bacterial movement, we used a high-throughput tracking technique to record the movement of many individual bacteria during temperature shifts. The speed of each bacterium varied strongly with temperature, closely following the Arrhenius rate law. Among bacteria, the prefactor A of the Arrhenius dependence unexpectedly varied exponentially with apparent activation energy, E(a), over a wide range (8-21 kcal/mol), reminiscent of the "rate compensation effect" of classical catalytic reactions. Average E(a) were increased for mutant bacteria deficient in binding Ena/VASP proteins and bacteria moving in diluted extract. These two effects were additive. The observed temperature and rate compensation effects are consistent with a class of simple kinetic models in which the bacterium advances through the thermally driven, cooperative breakage of groups of adhesive bonds on its surface. The estimated number of coupled adhesive bonds N on the bacterial surface varies between 10 and 40 bonds. In contrast to other models, this model correctly predicts an experimentally observed negative correlation between bacterial speed and actin gel density. The idea that speed depends on adhesion, rather than polymerization, suggests several alternative mechanisms by which known cytoskeletal regulatory proteins could control cellular movement.

Quartz crystal microbalance in elevated temperature viscous liquids: Temperature effect compensation and lubricant degradation monitoring

The quartz crystal microbalance (QCM) was extended to investigate viscous liquids at elevated temperatures in both isothermal and non-isothermal systems. An analysis of the frequency–temperature behavior of the QCM resulted in a new approach to compensate for the effect of the rate of temperature rise on the theoretical QCM temperature coefficients. The temperature-dependent viscosities of a series of liquids were evaluated by measuring the damping voltage of QCM. Thermal degradation experiments on pentaerythritol tetrapelargonate based lubricants demonstrated the potential application of QCM as an in situ sensor to evaluate the thermal stability of lubricants or other viscous fluids. The solid residue deposition rates and liquid phase property changes (i.e., product of density and viscosity) were extensively investigated by monitoring variations in the QCM frequency and damping voltage during the lubricant thermally stressing over a temperature range of 150–220 °C.

Compensation of temperature effects on the pull-in voltage of microstructures

The pull-in voltage of a suspended microstructure has been investigated for use as on-chip voltage reference in a compatible MEMS-IC process. Pull-in is detected using capacitive displacement measurement. The stability is affected by an initial parasitic charge build-up and a temperature sensitivity of −149 μV/K. A burn-in procedure is required to minimize the first effect. The temperature coefficient is compensated for by applying additional temperature dependent electrostatic energy to the microstructure. Devices fabricated in an epi-poly process and designed for a nominal pull-in voltage at 5 V have a measured value at 4.7424 V. Drift becomes negligible after 120 h of operation. The temperature reproducibility is within the resolution of the readout at 100 μV over a temperature range between 20 and 60 °C.

Growth and characterization of magneto-optical single-crystal ReYbBiIG with temperature-stabilized Faraday rotation

The Bi and Re (Re:Tb, Ho, etc.) partially substituted yttrium iron garnet bulk single crystals of (ReYbBi) 3Fe 5O 12 were grown by using Bi 2O 3/B 2O 3 as flux and accelerated crucible rotation technique for single-crystal growth. Results on the basis of temperature-changeable magneto-optical Faraday rotation spectra showed that their magneto-optical figures of merit were much higher than that of YIG in the wavelength range of 1.0–1.7 μm, while their Faraday rotation temperature coefficients were even smaller than that of YIG in the temperature range 10–80°C. According to temperature compensation effect, magneto-optical materials with temperature-stabilized Faraday rotation were achieved through compounding two kinds of rare-earth ions with opposite temperature coefficients, indicating an advantage for Faraday rotator usage in optical isolator with temperature-stable isolation.

Compensation of temperature effects in quartz crystal microbalance measurements

Quartz crystal microbalance (QCM) is a very powerful method for in situ monitoring of thin film growth processes. However, especially at high temperatures, QCM is very sensitive to already minor temperature changes during the measurement. Here, a method for compensating the temperature effects on the QCM is introduced. In this method, the baseline drift during the growth is calculated using a function obtained by fitting the signal measured before and after the growth. The present method is compared with the earlier published reference crystal method where two closely spaced quartz crystals are used, one being protected against film growth and thus serving as a reference crystal for compensating the temperature effects on the measurement crystal. Both methods were tested with TiO2 and Al2O3 atomic layer deposition processes and the temperature effect was successfully compensated. The differences between these methods are discussed.

The “Strain-Gauge Thermocouple”: A novel device for simultaneous strain and temperature measurement

A novel methodology for simultaneous strain and temperature measurements by means of an ac powered electrical resistance strain gauge connected to a strain conditioner using thermocouple wires is proposed and validated. To this aim a specific device has been designed and implemented; the characteristics of the electronic circuit for signal conditioning have then been tested in order to determine the overall performances in temperature and strain measurements. The field verification of the method is conducted by imposing strain fields in the range from 0 to about 700 μm/m and temperature variations in the range from −10 to 100 °C. The difference between the strain measured by the proposed device and the one evaluated by a conventional digital strain meter was always less than 4 μm/m while the mean temperature discrepancy was 0.5 °C with respect to the reference temperature measured with a K-type thermocouple. Finally, compensation of temperature effects on the actual strain value has been performed while the temperature ranges from ambient to 100 °C with a residual error value of 1.4±1 μm/m.

Kinetics of fatty acid degradation by psychrophilically grown anaerobic granular sludge

The kinetic parameters of anaerobic granular sludge, grown at 10–12°C in an expanded granular sludge bed (EGSB) reactor and fed with volatile fatty acid (VFA) mixtures, were determined in batch assays. The homoacetogenic, hydrogenotrophic and acetoclastic specific activities of the sludge at 10°C, measured after 306 days exposure to psychrophilic conditions were 1.744, and 0.296 and 0.331 g COD g −1 volatile suspended solids (VSS) day −1, respectively. At 30°C these values were 18.024, 2.732 and 2.204 g COD g −1 VSS day −1, respectively. The temperature characteristics of the granular sludge and the homoacetogenic enrichment culture from cultivated sludge showed that the temperature optima were still in the mesophilic range (30–40°C) even after long term (306 days) operation at low temperature (10–12°C). In the overall conversion rate for acetate and propionate, evidence for the temperature compensation effect was found. In contrast, no temperature compensation effect was present for butyrate degradation. The results of EGSB batch reactor experiments revealed apparent K m of the acetate and propionate degraders in the ranges of 39–58 mg COD l −1 and 7–14 mg COD l −1, respectively. For butyrate degraders, higher K m values were found, i.e., 142–243 mg COD l −1. The observed low K m values could be attributed to prevailing mixing conditions in the EGSB reactor system.

COTTON-COLOR INSTRUMENTATION ACCURACY: TEMPERATURE AND CALIBRATION PROCEDURE EFFECTS

Government cotton classing offices and gins with state-of-the-art process-control systems conduct automatedcotton-color measurements. Calibration of the color instrumentation involves the use of five colored ceramic tiles asreferences for input to a multiple-linear-regression model. In this study, two commercial color-measurement instrumentsrecorded color values of a set of 18 colored ceramic tiles at various time intervals. The effects of calibrating with fewer ofthe calibration tiles, of using a simpler calibration algorithm, and of temperature fluctuation, were determined regardinginstrument accuracy. Both methods of simplifying calibration (reducing the number of tiles and using a simple-linearmodel) had the same effect: better accuracy in the brightness measurement (Rd) and lower accuracy in the yellownessmeasurement (+b). Whereas +b is the more critical measurement, the multiple-linear model with four or five tiles issuperior overall. However, the difference is not so great as to render the simple-linear model with only two tilesinadequate in a process-control system that demands greater simplicity. Temperature changes were found to be correlatedwith changes in measured color values. The measured value of Rd trended downward with increasing temperature, butthere was no predictable trend in measured +b. Use of similar color instrumentation in a cotton gin would require somemethod of compensation for temperature effects.

Contactless potentiometer based on giant magnetoresistance sensors

We present a magnetic sensor based on the giant magnetoresistance (GMR) effect, which can be used as a contactless potentiometer. The sensor consists of a novel GMR sensor scheme with an artificial antiferromagnetic subsystem. The sensor gives a sinusoidal signal in dependence on the direction of a rotating external magnetic field Hrot. With two sensors in a planar setup, the whole 360° angle range can easily be covered. The amplitude ΔR/R of the signal is about 5%. The signal amplitude runs through a very flat maximum and changes only by 5% within a field range of about 4.4–27.2 kA/m. This large field range, the magnetic window (Hw), is the main advantage of this sensor compared to other magnetic sensor physical principles for contactless potentiometers. Therefore, large mounting tolerances and variations in the field strength of the rotating permanent magnet can be accepted. The temperature dependence of the sensor is linear both for the ground resistance (R0) and the signal amplitude (ΔR), allowing simple and effective electronic temperature compensation. The sensor can be operated up to 150 °C.