Portable Measurement Equipment Research Articles

Indirect measurement of infrared absorption spectrum through thermal emission of meta-cavity array.

Controlling thermal emission is essential for various infrared spectroscopy applications. Metasurfaces can be utilized to control multiple degrees of freedom of thermal emission, enabling the compact thermal emission materials and devices. Infrared spectroscopy such as FTIR (Fourier transform infrared spectroscopy), usually requires external infrared radiation source and complex spectroscopic devices for absorption spectrum measurement, which hinders the implementation of integrated compact and portable measurement equipment. Measuring absorption spectrum through the thermal emission of pixelated thermal emitter array can facilitate the integration and miniaturization of measurement setup, which is highly demanded for on-chip spectroscopy applications. Here, we experimentally demonstrate an integrated technology that allows for indirect measurement of the absorption spectrum through the thermal emission of meta-cavity array. This indirect measurement method opens a new avenue for compact infrared spectroscopy analysis.

Measurement of Ground Vibration for Unpaved Bridge Approach Field Model on Soft Soil

The information and the data of the bridge approach condition is important because it allows designers to know the response of the soil once loaded with vehicles and respectable suggestion for correct engineering solutions to beat the matter. There are a few clarifications the reason of problem occurred at bridge approach was recently inspected by other researchers previously and one of the issues is a dissimilarity between the height of the bridge and road on the connection. The objective of this research is characterize and create techniques for field investigation to inspect the effect of vibration from vehicle loading at bridge approaches and this case might be referred to as a repetitive cyclic loading. The aim of this research is to investigate critical location of vibration at bridge approach model by the influence and effect from measurement tools. This research concentrated on constructed field model of the unpaved bridge approach model in Research Centre for Soft Soil Malaysia (RECESS), Universiti Tun Hussein Onn Malaysia (UTHM), Johor, Malaysia. A portable measurement equipment system with high sensitivity triaxial ICP accelerometer used to investigate and measure the effect of vibration loading at unpaved bridge approach field model. Piezoelectric (ICP) accelerometer is now preferable for researchers for the field surveillance or laboratory testing. From the analysis, it can be stated here that the vibration value increases as the speed and vibration level produced changes from L1 to L2. In the transverse direction, it is found that P1 values are larger than P2 to P6 values at both sites BAA and BAB. On the longitudinal direction, the farther away the plate compactor is from the bridge model connection, its value decreases and it is found that the D1 area has a higher vibration value compared to D2 to D5. It may be then, concluded that in this research it is similar to the previous research at the actual study site where the vibration value is high in the area 1m to 2m from the bridge connection.

Spark plasma sintering compaction of hybrid nanodiamond/carbon nanotubes/metal electrode and its application

Nanodiamond has varies of mechanical, chemical and biomedical advantages, but its nano-size and discrete particle properties hinder its wide applications. In this work, we have fabricated a nanodiamond electrode by spark plasma sintering technology and applied it as a heavy metal detection sensor. The detonation nanodiamond was pressed by using spark plasma sintering compaction at 900 K under 0.2 GPa pressure. Then, its structure and composition were analyzed by many characteristic techniques, while the porous electrode having a density of 1.45 g/cm3 with hardness >0.17 GPa. Comparing with traditional carbon-based electrodes, the spark plasma sintering nanodiamond electrode is inexpensive and environment friendly. The analytical performance was characterized and optimized to be 1.52–2.82 μA·μg·L−1 for vary types of heavy metal ions in acetate buffering solution. Ultimately, with stable, accurate and precise electrochemical spectroscopy, this nanodiamond sensor permits rapid detection of Cd2+, Ni2+, Mn2+, Co2+ as well as Pb2+, and could potentially be coupled with point-of-use portable measurement equipment in order to substitute the noble electrodes.

In-situ measurements of hemp-lime insulation materials for energy efficiency improvement

Reduction of the CO2 emissions in the atmosphere is one of the goals set forth by the European Union, hence various directives have been adopted, such as the European directive 2012/27/EU on energy efficiency, i.e. ensuring from 2019 the construction of the near-zero energy buildings (nZEB). The construction segment plays a very important part in solving the current global problem of the greenhouse gas emissions and related processes of global warming, because in certain countries (i.e. in Latvia) it represents more than a half of the total energy consumption. Hence the necessity to elaborate means on how to boost the energy efficiency of the buildings meanwhile not rising pressure on the CO2 emissions released by the industry of construction materials and their transportation. Hemp-lime concrete is one of the materials that can be used to increase the energy efficiency, it is a new thermal insulation material produced from the local raw materials, and in its production cycle more CO2 is absorbed than produced. This research aims at determining the thermal insulation properties of this material in field conditions and comparing them with results from the laboratory measurements to analyse performance of such materials in the temperate continental climate zone of Europe. Measurements have been recorded on a specifically designed portable measurement equipment with sensors for the temperature, humidity and heat flux. The obtained results present a positive correspondence with the laboratory measurements, thus proving high potential for use of these materials to increase the energy efficiency of buildings.

Porosity evaluation of in-service thermal barrier coated turbine blades using a microwave nondestructive technique

Porosity inspection of composite materials, ceramics and polymers is an important practical consideration in the nondestructive evaluation/testing (NDE/T) industry. The porosity of ceramics such as yttria stabilized zirconia (YSZ), the most widely used thermal barrier coating (TBC), for hot section metal components in a gas turbine is highly correlated with the thermal conductivity performance of the component. In-situ porosity inspection of TBCs after cyclic service is crucial to ensure the operational quality of TBCs and avoid any catastrophic system failure. The ability of microwave signals to propagate through a dielectric material and interact with the underlying surface and intrinsic properties, combined with the availability of high-resolution portable measurement equipment, make microwave imaging an attractive candidate for in-situ porosity inspection. In this paper, an extensive analysis of the simulation and measurement using a X-band open-ended rectangular waveguide (OERW) energy launch to evaluate the porosity of the TBCs of turbine blades is given. Existing mixing models are verified using simulation to determine the porosity and its relation to dielectric properties. The results show that the OERW microwave NDT/E technique can be used to characterize the porosity of TBCs, after cyclic services, using the phase of the reflection coefficient, S11. The results are validated using waveguide dielectric property measurements and image analysis produced using a scanning electron microscope (SEM).

막장력 측정을 통한 막구조물의 장력 유지관리 시스템 검토

Membrane structure is a system that is stabilized by maintaining a tensile state of the membrane material that originally cannot resist the bending or pressure. Also, it is a system that allows the whole membrane structure to bear external loads caused by wind or precipitation such as snow, rain and etc. Tension relaxation phenomenon can transpire to the tension that is introduced to the fabric over time, due to the innate characteristics of the membrane material. Thus, it is important to accurately understand the size of the membrane tension after the completion of the structures, for maintenance and management purposes. The authors have proposed the principle of theoretically and indirectly measuring the tension by vibrating the membrane surface with sound waves exposures against the surface, which is compartmentalized by a rectangular boundary, and by measuring the natural frequency of the membrane surface that selectively resonates. The authors of this paper measured the tension of preexisting membrane structure for its maintenance by using the developed portable measurement equipment. Through analyzing the measurement data, the authors review the points that should be improved and the technical method for the new maintenance system of membrane tension.

Signal Conditioning System With a 4–20 mA Output for a Resonant Magnetic Field Sensor Based on MEMS Technology

Several resonant magnetic field sensors based on microelectromechanical systems (MEMS) technology use piezoresistive detection techniques to convert the magnetic field signal into an electrical signal. We present a signal conditioning system implemented in a printed circuit board (PCB) for a resonant magnetic field sensor based on MEMS technology. This sensor is formed by a resonant structure of thin silicon beams (5 μm thick), an aluminum loop (1 μm thick), and a Wheatstone bridge with four p-type piezoresistors. The Wheatstone bridge is biased with an alternating voltage of 2 Vpp at 1 kHz and the aluminum loop is supplied using an alternating current with a root-mean-square (RMS) value of 20 mA. This current is applied to the resonant frequency of the sensor (14.38 kHz) through an oscillator that has a frequency stability of ± 100 ppm at atmospheric temperature and a resolution of 1 Hz. The proposed system obtains the sensor's electrical response in voltage or current mode, which presents an approximately linear behavior for a range of magnetic field density from -150 to +150 μT. This system minimizes the offset of the sensor's electrical response and allows the detection of the polarity and magnitude of the magnetic field density. A virtual instrument is designed using Lab VIEW software to visualize the 4-20 mA output of the sensor. The designed system can help the development of portable measurement equipment to detect (at pressure atmospheric) low magnetic field densities with a sensitivity and resolution of 4 V · T-1 and 1 μT, respectively.

Evaluation of algorithms for calculating bioimpedance phase angle values from measured whole-body impedance modulus

This paper addresses the problem of calculating the bioimpedance phase angle from measurements of impedance modulus. A complete impedance measurement was performed on altogether 20 healthy persons using a Solatron 1260/1294 system. The obtained impedance modulus (absolute impedance value) values were used to calculate the Cole parameters and from them the phase angles. In addition, the phase angles were also calculated using a Kramers–Kronig approach. A correlation analysis for all subjects at each frequency (5, 50, 100 and 200 kHz) for both methods gave R2 values ranging from 0.7 to 0.96 for the Cole approach and from 0.83 to 0.96 for the Kramers–Kronig approach; thus, both methods gave good results compared with the complete measurement results. From further statistical significance testing of the absolute value of the difference between measured and calculated phase angles, it was found that the Cole equation method gave significantly better agreement for the 50 and 100 kHz frequencies. In addition, the Cole equation method gives the four Cole parameters (R0, R∞, τz and α) using measurements at frequencies up to 200 kHz while the Kramers–Kronig method used frequencies up to 500 kHz to reduce the effect of truncation on the calculated results. Both methods gave results that can be used for further bioimpedance calculations, thus improving the application potential of bioimpedance measurement results obtained using relatively inexpensive and portable measurement equipment.

Novel Received Signal Strength-Based Indoor Location System: Development and Testing

A received signal strength- (RSS-)-based indoor location method (ILS) for person/assets location in indoor scenarios is presented in this paper. Theoretical bases of the method are the integral equations relating the electromagnetic (EM) fields with their sources, establishing a cost function relating the measured field at the receivers and the unknown position of the transmitter. The aim is to improve the EM characterization of the scenario yielding in a more accurate indoor location method. Regarding network infrastructure implementation, a set of receivers are deployed through the coverage area, measuring the RSS value from a transmitter node which is attached to the asset to be located. The location method is evaluated in several indoor scenarios using portable measurement equipment. The next step has been the network hardware implementation using a wireless sensor network: for this purpose, ZigBee nodes have been selected. Finally, RSS measurements variability due to multipath effects and nonline-of-sight between transmitter and receiver nodes is mitigated using calibration and a correction based on the difference between the free space field decay law and the measured RSS.

A technique for power supply harmonic impedance estimation using a controlled voltage disturbance

A method for power system impedance estimation is presented. The method employs a power converter to inject a voltage transient onto the supply system. As the technique employs controlled power electronic devices it may be used as a stand alone piece of a portable measurement equipment, or it may be embedded into the functions of an active shunt filter for improved harmonic control. The impedance is estimated through correlation of the measured voltage and current transients. Simulations and experimental results demonstrate the measurement technique is highly accurate and effective.