An ultra high-pressure test rig for measurements of small flow rates with different viscosities

Within the framework of a research project regarding investigations on a high-pressure Coriolis mass flow meter (CMF) a portable flow test rig for traceable calibration measurements of the flow rate (mass - and volume flow) in a range of 5 g min⁻¹ to 500 g min⁻¹ and in a pressure range of 0.1 MPa to 85 MPa was developed. The measurement principle of the flow test rig is based on the gravimetrical measuring procedure with flying-start-and-stop operating mode. Particular attention has been paid to the challenges of temperature stability during the measurements since the temperature has a direct influence on the viscosity and flow rate of the test medium. For that reason the pipes on the high-pressure side are double-walled and insulated and the device under test (DUT) has an enclosure with a separate temperature control. From the analysis of the first measurement with tap water at a temperature of 20 °C and a pressure of 82.7 MPa an extensive uncertainty analysis has been carried out. It was found that the diverter (mainly due to its asymmetric behaviour) is the largest influence factor on the total uncertainty budget. After a number of improvements, especially concerning the diverter, the flow test rig has currently an expanded measurement uncertainty of around 1.0% in the lower flow rate range (25 g min⁻¹) and 0.25% in the higher flow rate range (400 g min⁻¹) for the measurement of mass flow. Additional calibration measurements with the new, redesigned flow test rig and highly viscous base oils also indicated a good agreement with the theoretical behaviour of the flow meter according to the manufacturers׳ specifications with water as test medium. Further improvements are envisaged in the future in order to focus also on other areas of interest.     

Determination of haloperidol drug in ampoules and in urine samples using a potentiometric modified carbon paste electrode

A modified carbon paste electrode for haloperidol drug based on haloperidol-phosphomolybdate (HP-PM) as an ion-exchanger dissolved in plasticizer DBP and its potentiometric characteristics were discussed. The electrode exhibited a good Nernstian slope of 56.9 ± 0.3 mV/decade with a linear concentration range from 3.2 × 10⁻⁶ to 1.0 × 10⁻² M for the haloperidol ion. The limit of detection (LOD) was 1.5 × 10⁻⁶ M. It had response time of 5–8 seconds (s), useable in pH range of 6.2–8.6 and temperature of 20–60 °C. The electrode shows clear discrimination of haloperidol drug from several inorganic ions, sugars and some common drug excipients. The sensor was applied for determination of haloperidol drug in urine and in pharmaceutical formulations using potentiometric determination, standard addition and the calibration curve methods. The results are satisfactory with excellent percentage recovery comparable or better than those obtained by other routine methods.     

On-site calibration system for trace humidity sensors

A portable device for calibration of trace humidity sensors and an adopted calibration procedure have been developed. The calibration device is based on humidity generation by permeating water through polymeric membrane tubes. Water vapour transmission rates for various polymers were experimentally determined in order to select the most suitable polymeric material. The developed trace humidity generator consists of a gas-flow polymeric hose immersed in a water reservoir thermostated by a sensor-controlled heater. Mole fractions of water vapour between 1 μmol mol⁻¹ and 350 μmol mol⁻¹ (equivalent to frost-point temperatures from −76 °C to −31 °C) were generated by varying either the operating temperature or gas flow. The operating temperature can be varied from 20 °C to 60 °C and kept stable within 0.1 K. Uncertainty analysis indicated that the trace humidity generator produces gas flows of constant humidity amounts with a relative expanded uncertainty less than 3.4% (k = 2) of the generated value.     

Multi-range sensors for the measurement of liquid film thickness distributions based on electrical conductance

The paper presents an approach toward an enhancement of the measuring range of high-speed sensors for the measurement of liquid film thickness distributions based on electrical conductance. This type of sensors consists of electrodes mounted flush to the wall. The sampling of the current generated between a pair of neighboring electrode is used as a measure of the film thickness. Such sensors have a limited measuring range, which is proportional to the lateral distance between the electrodes. The range is therefore coupled to the spatial resolution. The proposed new design allows an extension of the film thickness range by combining electrode matrices of different resolution in one and the same sensor. In this way, a high spatial resolution is reached with a small thickness range, whereas a film thickness that exceeds the range of the high resolution measurement can still be acquired even though on the costs of a lower spatial resolution. A simultaneous signal acquisition with a sampling frequency of 3.2 kHz combines three measuring ranges for the characterization of a two-dimensional film thickness distribution: (1) thickness range 0–600 µm, lateral resolution 2×2 mm², (2) thickness range 400–1300 µm, lateral resolution 4×4 mm², and (3) thickness range 1000–3500 µm, lateral resolution 12×12 mm². The functionality of this concept sensor is demonstrated by tests in a horizontal wavy stratified air–water flow at ambient conditions. Using flexible printed circuit board technology to manufacture the sensor makes it possible to place the sensor at the inner surface of a circular pipe.     

Artificial neural network modeling of thin layer drying behavior of municipal sewage sludge

The back-propagation (BP) and generalized regression neural network models (GRNN) were investigated to predict the thin layer drying behavior in municipal sewage sludge during hot air forced convection. The accuracy of the BP model to predict the moisture content of the sewage sludge thin layer during hot air forced convective drying was far higher than that of the GRNN model. The GRNN models could automatically determine the best smoothing parameters, which were 0.6 and 0.3 for predicting the moisture content and average temperature, respectively. The model type for predicting the average temperature of the sewage sludge thin layer was selected for different sample groups by comparing their MSE values or R² values. The GRNN model was suitable for predicting the average temperature corresponding to the sample groups at hot air velocity of 0.6 m/s, and drying temperatures of 100 °C, 160 °C; hot air velocity of 1.4 m/s, and drying temperatures of 130 °C, 140 °C; hot air velocity of 2.0 m/s, and drying temperatures of 150 °C, 160 °C. The average temperature for the other sample groups was best predicted by the BP model.     

Non-contact temperature measurement of silicon wafers based on the combined use of transmittance and radiance

We propose a non-contact temperature measurement method that combines the temperature dependence of transmittance below 600 °C and radiation thermometry above 600 °C. The combined method uses a polarization technique and the Brewster angle between air and a dielectric film such as SiO₂ or Si₃N₄ grown on silicon wafers. A prominent feature of this method is that both measurements of transmittance and radiance are performed with the same geometrical arrangement.For a semitransparent wafer, the measurement of p-polarized transmittance at the wavelengths of 1.1, 1.2 and 1.3 μm enables temperature measurement in the range from room temperature to 600 °C. For an opaque wafer above 600 °C, the p-polarized radiation thermometry at the wavelength of 4.5 μm allows the temperature measurement without the emissivity problem. The combined method with the use of transmittance and radiance is valid in the entire temperature range irrespective of variations of film thickness and resistivity.     

Atomic force microscope probe calibration by use of a commercial precision balance

In this paper, we investigate the characteristics of a piezoresistive AFM cantilever in the range of 0–1.6 μN by using nano force calibrator (NFC), which consists of a high precision balance with resolution of 1 nN and 1-D fine positioning stage. Brief modeling of the cantilever is presented and then, the calibration results are shown. Tests revealed a linear relationship between the probing force and sensor output (resistance change), but the force vs. deflection is not as linear as the force vs. sensor output curve. The force constant of the cantilever was measured to 0.26 N/m with a standard deviation of 0.01 N/m. It shows that there is big difference between measured and nominal spring constant of 1 N/m provided by the manufacturer’s specifications.     

High-precision and high-speed positioning of 100 G linear synchronous motor

The present paper describes a moving permanent magnet linear synchronous motor (MPM LSM) that can move with an acceleration above 100 G (=980 m/s²), and is also capable of high-precision and high-speed positioning. The MPM LSM consists of a mover including permanent magnets and a double-sided electromagnet stator. It can produce a thrust of 4.56 × 10³ N and has a working range wider than 1 m. The MPM LSM mover is improved for light weight and is driven using a suitable phase lead for flux weakening. The combination of the improved mover and the suitable phase lead provides motion at an acceleration above 100 G and a velocity above 12 m/s. The positioning characteristics of the improved MPM LSM are examined using a controller with two suitable phase lead functions. The control system shows a positioning accuracy and a positioning resolution of 500 nm, which is similar to the vibration amplitude of the sensor output in open loop. In 300-mm step positioning, the improved MPM LSM shows an acceleration above 660 m/s² and a velocity above 8.3 m/s. It takes less than 101 ms to reduce the positioning error to less than 5 μm. The temperature rise during positioning is also examined experimentally. Continuous positioning for longer than 30 minutes increases the temperature of the MPM LSM, but by less than 6 °C.     

Design and experimental validation of an ultra-precision Abbe-compliant linear encoder-based position measurement system

The design and development of an Abbe-compliant linear encoder-based measurement system for position measurement with a targeted 20 nm uncertainty (k = 2) in machine tools and CMMs is presented. It consists of a linear scale and a capacitive sensor, mounted in line on an interface which is guided in the scale's measurement direction and driven by a linear motor based on the output signal of the capacitive sensor. The capacitive sensor measures the displacement of a target surface on the workpiece table. The functional point, which is the center of a tool or touch probe, is always aligned with the scale and capacitive sensor such that this configuration is compliant with the Abbe principle. Thermal stability is achieved by the application of a thermal center between the scale and capacitive sensor at the tip of the latter, which prevents both components to drift apart. Based on this concept, a prototype of a one-DOF measurement system was developed for a measurement range of 120 mm, together with an experimental setup aimed at verifying the reproducibility of the system for changing ambient conditions of ±0.5 °C and ±5%rh and the repeatability during tracking of a target surface over a short period of time. These experiments have shown that the measurement uncertainty of the one-DOF system is below 29 nm with a 95% confidence level.     

Uncertainty evaluation of the 20 kN m deadweight torque standard machine

A deadweight-type torque standard machine of 20 kN m rated capacity (20 kN m-DWTSM) has been designed and developed by the National Metrology Institute of Japan (NMIJ) at the National Institute of Advanced Industrial Science and Technology (AIST). Each uncertainty contribution comes mainly from the performance of each mechanical part of the 20 kN m-DWTSM. Authors evaluated the uncertainty of the mass of the linkage weights, local acceleration of gravity, influence of air buoyancy on deadweight loading, initial moment-arm length (including CMM measurement and temperature compensation), and sensitivity of the fulcrum. This report deals especially with evaluation of the remaining contributions, namely the influence of arm flexure and reference line variation at the end of the moment-arm on best measurement capability (BMC). Estimation of BMC in the 20 kN m-DWTSM gave a relative expanded uncertainty of less than 7.0 · 10⁻⁵ (k = 2) for the calibration range from 200 N m to 20 kN m.     

Studies of high temperature sliding wear of metallic dissimilar interfaces IV: Nimonic 80A versus Incoloy 800HT

Wear variations of Nimonic 80A slid against Incoloy 800HT between room temperature (RT) and 750 °C, and sliding speeds of 0.314 and 0.905 m s⁻¹ were investigated using a ‘reciprocating-block-on-cylinder’, low debris retention configuration. These were considered alongside previous observations at 0.654 m s⁻¹.Different wear types occurring were mapped, including high transfer ‘severe wear’ (RT and 270 °C, also 0.905 m s⁻¹ at ≤570°C), low transfer ‘severe wear’ (0.314 m s⁻¹ at 390 °C to 510 °C oxide abrasion assisted at 510 °C), and ‘mild wear’ (0.314 m s⁻¹ at ≥570 °C; 0.905 m s⁻¹ at ≥630 °C). Wear surfaces at 750 °C were cross-sectioned and profiled.     

Erosion-oxidation of uncoated,aluminized and chromized-aluminized 9Cr–1Mo steels under fluidized-bed conditions at 550–700 °C

Protective coatings, deposited mainly by thermal spraying and diffusion techniques, are considered a solution to extend the lifetime of many components in the energy production sector, such as heat exchangers. In this paper, some results are presented for uncoated, aluminized and chromized-aluminized 9Cr–1Mo steel, subjected to air and to impacts by 200 μm silica particles at angles of 30° and 90° and speeds of 7.0–9.2 m s^?1 at 550 –700 °C, in a laboratory fluidized-bed rig, to determine whether or not aluminized and chromized-aluminized diffusion coatings could protect the steel under such conditions. Erosion-oxidation damage was characterized by measurement of the mean thickness changes using a micrometer and examination of worn surfaces by scanning electron microscopy.Under most conditions, the coatings provided some protection to the substrate: under 30° impacts, up to 650 °C, and under 90° impacts, at 700 °C, both coatings were effective, whereas under 90° impacts, up to 650 °C, only the chromized-aluminized coating gave significant protection. However, for 30° at 700 °C, the oxide scale on the substrate was protective and the coatings were not needed. Explanations for these observations are presented in this paper, in terms of interactions between the erosion and oxidation processes for the materials.     

Development of a simple ‘temperature versus sliding speed’ wear map for the sliding wear behaviour of dissimilar metallic interfaces

The variation in wear behaviour during limited debris retention sliding wear of Nimonic 80A versus Stellite 6 (counterface) between room temperature and 750 °C, at sliding speeds of 0.314, 0.654 and 0.905 m s⁻¹, was investigated. At 0.314 m s⁻¹, mild oxidational wear was observed at all temperatures, due to transfer and oxidation of Stellite 6-sourced debris to the Nimonic 80A and resultant separation of the Nimonic 80A and Stellite 6 wear surfaces. Between room temperature and 450 °C, this debris mostly remained in the form of loose particles (with only limited compaction), whilst between 510 and 750 °C, the particles were compacted and sintered together to form a wear protective ‘glaze’ layer.At 0.654 and 0.905 m s⁻¹, mild oxidational wear due to transfer and oxidation of Stellite 6-sourced debris was only observed at room temperature and 270 °C (also 390 °C at 0.654 m s⁻¹). At 390 °C (450 °C at 0.654 m s⁻¹) and above, this oxide was completely absent and ‘metal-to-metal’ contact resulted in an intermediate temperature severe wear regime—losses in the form of ejected metallic debris were sourced almost completely from the Nimonic 80A. Oxide debris, this time sourced from the Nimonic 80A sample, did not reappear until 570 °C (630 °C at 0.654 m s⁻¹), however, were insufficient to eliminate completely severe wear until 690 and 750 °C. At both 0.654 and 0.905 m s⁻¹, the oxide now preventing severe wear at 690 and 750 °C tended not to form ‘glaze’ layers on the surface of the Nimonic 80A and instead supported continued high wear by abrasion. This abrasive action was attributed to the poor sintering characteristics of the Nimonic 80A-sourced oxide, in combination with the oxides’ increased mobility and decreased residency.The collected data were used to compose a simple wear map detailing the effects of sliding speed and temperature on the wear of Nimonic 80A slid against Stellite 6, at these speeds and temperatures of between room temperature and 750 °C.     

An all-fiber Fabry-Pérot interferometer for pressure sensing in different gaseous environments

A gas pressure sensor based on an all-fiber Fabry-Pérot interferometer (FFPI) is reported. The sensing head consists of a small section of silica rod spliced with a large offset between two single-mode fibers. The silica rod is used only as mechanical support so that an air cavity can be formed between both SMF. It is shown that the FFPI sensor is sensitive to gas pressure variation and when submitted to different gaseous environments, namely carbon dioxide, nitrogen and oxygen – sensitivities of 6.2, 4.1 and 3.6 nm/MPa, respectively, were attained. The refractive index change on nitrogen environment by means of gas pressure variation was also determined and a sensitivity of 1526 nm/RIU was obtained. The response of the sensing device to temperature variations in air was also studied and a sensitivity of −14 pm/°C was attained.     

Influence of temperature on the fretting response between AISI 301 stainless steel and AISI 52100 steel

Fretting of AISI 301 stainless steel sheet in contact with AISI 52100 steel from 20 °C to 550 °C in air and argon has been studied. Transitions in the mechanical properties of 301SS and oxidative behavior of this pair have been identified as a function of temperature. Strength and ductility of 301SS is reduced from 20 °C to 250 °C, increasing susceptibility to fretting damage. Steady state friction decreases as temperature increases, reducing cyclic stresses. Wear resistance increases in this temperature range, increasing fatigue damage due to the increase in fatigue life associated with increased wear. This study aims to identify the causes of the transitions in behavior and determine the net outcome of the competing effects with regard to fatigue damage.     

The design of polyaniline based sensor for the qualitative estimation of malonaldehyde

The detection of contaminated food in every stage of processing required new technology for fast identification and isolation of toxicity in food. Since effect of food contaminant are severe to human health, the need of pioneer technologies also increasing over last few decades. In the current study, MDA was prepared by hydrolysis of 1,1,3,3-tetramethoxypropane in HCl media and used in the electrochemical studies. The electrochemical sensor was fabricated with modified glassy carbon electrode with polyaniline. These sensors were used for detection of sodium salt of malonaldehyde and observed that a high sensitivity in the concentration range ∼1 × 10⁻¹ M and 1 × 10⁻² M. Tafel plots show the variation of over potential from − 1.73 V to − 3.74 V up to 10⁻⁵ mol/L indicating the lower limit of detection of the system.     

Development and evaluation of a two-axial shearing force sensor consisting of an optical sensor chip and elastic gum frame

We developed a promising shearing force sensor that is small in size and can measure shearing force along two axes independently. This sensor consists of an elastic gum frame and an optical sensor chip (6 mm × 6 mm × 8 mm). From the experimental results, the resolutions of the sensor along the x- and y-axes are found to be 0.070 N and 0.063 N. We also experimentally demonstrated that the sensor can separately measure shearing force along two axes. Finally, we demonstrated that the scale factor which correspond to resolution and linear portion which correspond to measuring range of the signals can be changed easily by using three types of elastic gum frame. This sensor can be embedded in the finger of a robot hand and use it to not only measure shearing force but also detect the slip phenomenon.     

Determination of the thermal conductivity of composted material

The objective of this study was to develop a reliable method for the determination of the thermal conductivity of composted material using the TP08 probe. Study was set out to determine whether the selection of a signal fragment used to establish thermal conductivity (λ), has a significant influence on the results. Also minimum number of measurements was determined for every phase of the composting process. No significant differences were reported between results, but certain changes in the value of λ were noted. In successive stages of the process, thermal conductivity of composted material were: 0.31 ± 0.09, 0.45 ± 0.14, 0.27 ± 0.03 and 0.37 ± 0.17 W m⁻¹ K⁻¹.     

WC–ZrO2 composites: processing and unlubricated tribological properties

In the present work, we report the processing and properties of WC–6 wt.% ZrO₂ composites, densified using the pressureless sintering route. The densification of the WC–ZrO₂ composites was carried out in the temperature range of 1500–1700 °C with varying time (1–3 h) in vacuum. The experimental results indicate that significantly high hardness of 22–23 GPa and moderate fracture toughness of ∼5 MPa m^1/2 can be obtained with 2 mol% Y-stabilized ZrO₂ sinter-additive, sintered at 1600 °C for 3 h. Furthermore, the friction and wear behavior of optimized WC–ZrO₂ composite is investigated on a fretting mode I wear tester. The tribological results reveal that a moderate coefficient of friction in the range from 0.15 to 0.5 can be achieved with the optimised composite. An important observation is that a transition in friction and wear with load is noted. The dominant mechanisms of material removal appear to be tribochemical wear and spalling of tribolayer.     

Miniaturized liquid film sensor (MLFS) for two phase flow measurements in square microchannels with high spatial resolution

Two miniaturized liquid film sensors (MLFS) based on electrical conductance measurement have been developed and tested. The sensors are non-intrusive and produced with materials and technologies fully compatible and integrable with standard microfluidics. They consist of a line of 20 electrodes with a purpose-designed shape, flush against the wall, covering a total length of 5.00 and 6.68 mm. The governing electronics achieve 10 kHz of time resolution. The electrode spacing of the two sensors is 230 μm and 330 μm, which allows measurements of liquid films up to 150 μm and 400 μm for sensors MLFS_A and MLFS_B, respectively. The sensor characteristics were obtained by imposing static liquid films of known thickness on top of the actual sensor. Further dynamic measurements of concurrent air-water flow in a horizontal microchannel were performed. The line of electrodes is placed across the flow direction with an angle of 3.53° from the direction of flow, allowing for a spatial resolution perpendicular to the flow of 14.2 μm for sensor MLFS_A and 20.5 μm for sensor MLFS_B. The high time and spatial resolution allows for fast and accurate detection of the presence of bubbles, and even measurement of film thickness and bubble velocity. Further information, such as the bubble shape, can be gathered based on the shape of the liquid layer underneath the bubble, which is particularly important for heat transfer studies in microchannels.