A Pitot tube system for obtaining water velocity profiles with millimeter resolution in devices with limited optical access

An automated, miniature, S-type Pitot tube system was created to obtain fluid velocity profiles at low flows in equipment having limited optical access, which prevents the use of standard imaging techniques. Calibration of this non-standard Pitot tube at small differential pressures with a custom, low-pressure system is also described. Application of this system to a vertical, high-pressure, water tunnel facility (HWTF) is presented. The HWTF uses static flow conditioning elements to stabilize individual gaseous, liquid, or solid particles with water for optical viewing. Stabilization of these particles in the viewing section of the HWTF requires a specific flow field, created by a combination of a radially expanding test section and a special flow conditioner located upstream of the test section. Analysis of the conditioned flow field in the viewing section of the HWTF required measurements across its diameter at three locations at 1 mm spatial resolution. The custom S-type Pitot tube system resolved pressure differences of <100 Pa created by water flowing at 5–30 cm/s while providing a relatively low response time of ~300 s despite the small diameter (<1 mm) and long length (340 mm) of the Pitot tube needed to fit the HWTF geometry. Particle imaging velocimetry measurements in the central, viewable part of the HWTF confirmed the Pitot tube measurements in this region.     

Measurement and statistical analysis toward reproducibility validation of AZ4562 cylindrical microlenses obtained by reflow

This paper presents the statistical analysis applied into the shape of microlenses (MLs) for validating the high-reproducibility feature of their fabrication process. The MLs were fabricated with the AZ4562 photoresist, using photolithography and thermal reflow processes. Two types of MLs arrays were produced for statistical analysis purposes: the first with a cross-sectional diameter of 24 μm and the second with a cross-sectional diameter of 30 μm, and both with 5 μm spacing between MLs. In the case of 24 μm diameter arrays, the measurements showed a mean difference in diameter of 2.78 μm with a standard deviation (SD) of 0.22 μm (e.g., 2.78 ± 0.22 μm of SD) before the reflow, and 2.34 ± 0.35 μm of SD after the reflow. For the same arrays, the mean difference in height obtained was, comparatively to the 5.06 μm expected, 0.76 ± 0.10 μm of SD before the reflow and 1.91 ± 0.15 μm of SD after the reflow, respectively. A mean difference in diameter of 2.64 ± 0.41 μm of SD before the reflow, and 1.87 ± 0.34 μm of SD after the reflow was obtained for 30 μm diameter MLs arrays. For these MLs, a mean difference in height of 0.71 ± 0.12 μm of SD before the reflow and 2.24 ± 0.24 μm of SD after the thermal reflow was obtained, in comparison to the 5.06 μm of height expected to obtain. These results validate the requirement for reproducibility and opens good perspectives for applying this fabrication process on high-volume production of MLs arrays.     

Measurement of seed spacing uniformity performance of a precision metering unit as function of the number of holes on vacuum plate

The objective of the study was to determine the seed spacing uniformity performance of a precision metering unit when vacuum plates with different number of holes were used. In order to meet this objective, the performances of vacuum plates with different number of holes were evaluated in the laboratory conditions by employing sticky belt tests and seed spacing values were measured computerized measurement system (CMS) for the cotton and corn seeds. Quality of feed index, multiple index, miss index as well as coefficient of precision (CP3) were considered as the performance indicators for precision seeding. The forward speed values were as selected as 1.0, 1.5 and 2.0 m s⁻¹ while vacuum plates with hole diameter of 3.5 mm for cotton and 4.5 mm for corn seeds were used. For both, cotton and corn seeds, five different vacuum plates (20, 26, 36, 52, and 72 holes) were considered in the experiments. In the experiments, vacuum pressure was applied at 6.3 kPa. Based on the findings in this work it appears that 1.0 and 1.5 m s⁻¹ of forward speed values were found to provide the highest performance levels for all vacuum plates. However such performance substantially decreased when forward speed increased to 2.0 m s⁻¹. In overall, the highest performance was determined when 26 and 36 holes were used for cotton and corn, respectively.     

A robust QRS detection using novel pre-processing techniques and kurtosis based enhanced efficiency

The QRS complex detection is very imperative step prior to detecting any other wave component, beat segments, or any other morphological parameters of electrocardiogram (ECG). The paper presents a novel technique for QRS complex detection with minimum pre-processing required. The technique uses two-stage median filter and Savitzky–Golay smoothing filter for pre-processing. The decision rule is based on root-mean-square of the signal. The technique evolves with a novel approach for isoelectric line detection and a kurtosis-based false positive correction method. The robustness of the proposed technique been substantiated on Fantasia Database (FTD), MIT-BIH Arrhythmia Database (MIT-AD), MIT-BIH Normal Sinus Rhythm Database (MIT-NSD), and BIDMC Congestive Heart Failure Database (CHFD). The detection sensitivity (Se), positive predictivity (+P), detection error rate (DER), and accuracy (Ac) of proposed technique on FTD is Se = 99.90%, +P = 99.91%, DER = 0.19%, and Ac = 99.81%. On MIT-AD the technique has Se = 99.50%, +P = 99.56%, DER = 0.93%, and Ac = 99.08%. The technique shows Se = 99.36%, +P = 99.43%, DER = 1.21%, and Ac = 98.81% on MIT-NSD. Tested on CHFD, the techniques has Se = 99.68%, +P = 99.78%, DER = 0.52%, and Ac = 99.46%. The technique is also tested on self-recorded data-set and has Se = 99.97%, +P = 99.99%, DER = 0.04%, and Ac = 99.96%. The observation of above results shows the high performance and robustness of QRS complex detection, which will lead to highly accurate cardiac health prognosis.     

AC conduction mechanism and battery discharge characteristics of (PVC/PEO) polyblend films complexed with potassium chloride

New K⁺ ion-conducting polymer blend electrolyte films based on amorphous polymer poly(vinyl chloride) (PVC) and semicrystalline polymer poly(ethylene oxide) (PEO) complexed with KCl salt were prepared using a solution-cast technique. The maximum value of ionic conductivity of a PVC/PEO:KCl (42.5:42.5:15) system is 8.29 × 10⁻⁶ S/cm at 303 K. The absorption edge was found at 4.30 eV for undoped film, while it was observed at 4.03 and 3.93 eV for 10 and 15 wt% KCl doped films, respectively. The direct band gaps for these pure and salt doped PVC/PEO films were found to 4.10, 3.86 and 3.74 eV, respectively, whereas the indirect band gaps were determined as 4.15, 3.72 and 3.64 eV. Transference number values showed that the charge transport in this electrolyte system is predominantly due to ions (t_ion = 0.97). The discharge capacity for PVC/PEO:KCl (42.5:42.5:15) polymer blend electrolyte system is 11 μA/h.     

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.     

Improving the etching performance of high-aspect-ratio contacts by wafer temperature control: Uniform temperature design and etching rate enhancement

A novel wafer temperature control system using direct expansion cycles is developed to improve etching performance. This system enables rapid temperature control of a wafer with low power consumption. In a previous report, we confirmed that the etching rate and mask selectivity of high-aspect-ratio contact etching could be increased by around 6% and 14%, respectively, by controlling the temperature of the wafer during the etching process. In this study, an advanced wafer temperature control system that realizes not only rapid response but also uniform wafer cooling is developed, and a new etching process that controls O₂ gas flow rate as well as wafer temperature during etching is evaluated to decrease the etching rate depression of high-aspect-ratio contact etching. As a result, a rate of wafer temperature change of 1 °C/s and uniformity of ±0.7% with a coefficient of performance exceeding 3 is achieved over a wafer with a diameter of 300 mm during the etching process. Furthermore, etching rate depression in C₄F₆/Ar/O₂ plasma is decreased from 14.4% to 7.8% for a sample with a diameter of 100 nm and aspect ratio of 30.     

Design and validation of a grinding wheel optical scanner system to repeatedly measure and characterize wheel surface topography

This paper describes the design and validation of an upgraded grinding wheel scanner system that controls the position of a Nanovea CHR-150 Axial Chromatism sensor along the x- and y-directions of the wheel surface to measure and characterize wheel surface topography. The scanner features a novel homing system that enables the wheel to be removed from the scanner, used on a grinding machine and then re-mounted and re-homed so that the same location on the wheel surface can be repeatedly measured and monitored. The average standard deviation for homing was 27.6 μm and 19.3 μm in the x- and y-directions, respectively, which is more than adequate for typical area scans of 25 mm². After homing, the scanner was able to repeatedly measure features that were similar in size to an abrasive grain (∼200 μm diameter) with an average error of 9.3 μm and 5.9 μm in the x- and y-directions, respectively. The resulting topography measurements were compared with Scanning Electron Microscope images to demonstrate the accuracy of the scanner. A custom particle filter was developed to process the resulting data and a novel analysis technique involving the rate of change of measured area was proposed as a method for establishing the reference wheel surface from which desired wheel topography results can be reported such as the number of cutting edges, cutting edge width and cutting edge area as a function of radial depth.     

Performance tests of a new non-invasive sensor unit and ultrasound electronics

Industrial applications involving pulsed ultrasound instrumentation require complete non-invasive setups due to high temperatures, pressures and possible abrasive fluids. Recently, new pulser-receiver electronics and a new sensor unit were developed by Flow-Viz. The complete sensor unit setup enables non-invasive Doppler measurements through high grade stainless steel. In this work a non-invasive sensor unit developed for one inch pipes (22.5 mm ID) and two inch pipes (48.4 mm ID) were evaluated. Performance tests were conducted using a Doppler string phantom setup and the Doppler velocity results were compared to the moving string target velocities. Eight different positions along the pipe internal diameter (22.5 mm) were investigated and at each position six speeds (0.1–0.6 m/s) were tested. Error differences ranged from 0.18 to 7.8% for the tested velocity range. The average accuracy of Doppler measurements for the 22.5 mm sensor unit decreased slightly from 1.3 to 2.3% across the ultrasound beam axis. Eleven positions were tested along the diameter of the 48.4 mm pipe (eight positions covered the pipe radius) and five speeds were tested (0.2–0.6 m/s). The average accuracy of Doppler measurements for the 48.4 mm sensor unit was between 2.4 and 5.9%, with the lowest accuracy at the point furthest away from the sensor unit. Error differences varied between 0.07 and 11.85% for the tested velocity range, where mostly overestimated velocities were recorded. This systematic error explains the higher average error difference percentage when comparing the 48.4 mm (2.4–5.9%) and 22.5 mm (1.3–2.3%) sensor unit performance. The overall performance of the combined Flow-Viz system (electronics, software, sensor) was excellent as similar or higher errors were typically reported in the medical field. This study has for the first time validated non-invasive Doppler measurements through high grade stainless steel pipes by using an advanced string phantom setup.     

An orifice meter for bidirectional air flow measurements: Influence of gas thermo-hygrometric content on static response and bidirectionality

This paper presents the design and calibration of an ISO non-compliant orifice plate flowmeter whose intended use is for respiratory function measurements in the bidirectional air flow range ±9 L/min.The novelty of the proposed sensor consists of a plate beveled in both upstream and downstream sides: a symmetrical geometry is adopted in order to perform bidirectional measurements of flow rate. A mathematical model is introduced to quantify the influence of temperature on the sensor output. Four different positions of the pressure static taps are evaluated in order to maximize bidirectionality. An index is also introduced in order to quantitatively estimate the anti-symmetry of the sensor's response curve.Trials are carried out to evaluate the influence on sensor output of air temperatures (22 °C, 30 °C and 37 °C) at different values of relative humidity (5%, 55% and 85%). Experimental data show a quite good agreement with the theoretical model (R²>0.98 in each condition).The influence of air temperature on the sensor output is minimized by introducing a correction factor based on the theoretical model leading to measurement repeatability better than 2% in overall range of calibration. The mean sensitivity in the calibration range is about 2 kPa L⁻¹·min allowing to obtain a sensor discrimination threshold lower than 0.2 L/min in both directions. The time constant of the whole measurement system, equal to 2.40±0.03 ms, leads to a bandwidth up to 80 Hz making the sensor suitable for respiratory function measurements.     

Study on the evaluation of cylinder’s global sizes

In ISO 14405-1, the global sizes, such as least-squares diameter, minimum circumscribed diameter and maximum inscribed diameter are defined. The diameters above can be measured by using cylindrical coordinate measuring method like the circular section measuring method of cylindricity error. The determination method of the least-squares diameter was firstly given based on the cylindrical measuring system, and the optimization models of the minimum circumscribed diameter and the maximum inscribed diameter were built, respectively. The corresponding objective functions were unified as “minimax” expressions. For the four axis parameters of the cylinder with the minimum circumscribed diameter or the maximum inscribed diameter, the searching ranges of cylinder’s axis parameters for their optimal solutions were defined numerically. Thereafter, the genetic, steepest decent and BFGS-0.618 algorithms were introduced, and the optimization evaluation algorithms of two kinds of diameters mentioned above were given. Based on many cylinders’ profiles obtained by the circular section measuring method on a measuring instrument of cylinder’s global sizes which was developed by Zhongyuan University of Technology, Zhengzhou, China. The accuracy, efficiency and suitability of three optimization algorithms were investigated through the evaluation of a lot of the minimum circumscribed diameters and the maximum inscribed diameters. The measurement uncertainty of the global sizes for the cylindrical specimen was analyzed, and the measurement uncertainties of the sizes in the radial and z directions are ±0.95 μm and ±0.5 μm, respectively. The total measurement uncertainties of the global sizes of the cylindrical specimens with the specifications of ϕ10 × 120 mm and ϕ100 × 300 mm are ±3.8 μm and ±5.7 μm, respectively. The investigation results showed that for the evaluation of the globe sizes, any one of three algorithms above is not absolutely prior to the other two algorithms while considering both evaluation accuracy and efficiency, and the difference of their evaluation results do not exceed 0.5 μm. On the other hand, many points between the maximum value and the least value do not affect the evaluation results in optimization process. For improving the evaluation efficiency, by de-selecting those points while considering the characteristic parameter was also studied based on the statistic method and experiment. Coefficient t should be less than 0.3 to ensure the evaluation accuracy. This research may be useful for developing the next generation measurement instrument for the global sizes and the way forward for the digital manufacturing.     

Uncertainty analysis of slot die coater gap width measurement by using a shear mode micro-probing system

A shear mode micro-probing system was constructed for gap measurement of a precision slot die coater with a nominal gap width of 90 μm and a length of 200 mm. A glass micro-stylus with a nominal tip ball diameter of 52.6 μm was oscillated by a tuning fork quartz crystal resonator with its oscillation direction parallel to the measurement surfaces. An on-line qualification setup was established to compensate for the influences of the uncertainty sources, including the water layers on the measurement surfaces. The measurement uncertainty of the measured gap width was estimated to be less than 100 nm.     

Tribological characterisation of siliconcarbonitride ceramics derived from preceramic polymers

Amorphous SiCN ceramics were prepared in a laboratory scale as disk shaped specimens with 10 mm diameter and 0.3 mm thickness. The friction and wear behaviour was characterised in gross slip fretting tests under unlubricated conditions at room temperature against steel (100Cr6) and ceramic (Al₂O₃). Tests with a ball-on-disk contact were performed in laboratory air with different content of water vapour. The results show clearly that the relative humidity has a significant effect on friction and wear behaviour. All tests in dry air lead to higher friction and higher wear rate than in normal air. Improved friction and wear behaviour was observed with increasing pyrolysis temperature up to 1100 °C of the SiCN specimens. This is attributed to increasingly better mechanical properties and higher stiffness of the amorphous network due to the evaporation of gaseous organic species and the formation of free graphite like carbon.     

Preparation,characterization, electrical conductivity and dielectric studies of Na2SO4 and V2O5 composite solid electrolytes

Composite solid electrolytes (1 − x) Na₂SO₄–(x) V₂O₅ were prepared and characterized by various techniques such as XRD, FT-IR, DTA and SEM. AC impedance spectroscopy revealed that the contribution of grain is strong enough over the grain boundary. Arrhenius plot of the Na₂SO₄ shows a sharp increase in conductivity at 523 K due to the structural phase transition (phase V → I). Composites show the enhanced ionic conductivity than the pristine Na₂SO₄ over the entire temperature range. The maximum conductivity σ = 0.003 S cm⁻¹ at 773 K with the lowest activation energy of 0.28 eV was observed for the x = 0.4 sample. The enhanced value of dielectric constant and dielectric loss in the case of composites was obtained because of increase of conductivity, resulted from the increase of space charge polarization and charge motion.     

Nanowire cutting by an ultrasonically vibrating micro tool

Cutting of a nanoscale workpiece is useful in nano testing and fabrication, and novel cutting methods with little gasification of cut nano samples and simple device structures are needed for practical applications. In this paper, an ultrasonic nanowire cutting strategy is demonstrated, in which the linear and elliptical vibration of the tip of a micro cutting tool and the adhesion force between a substrate and nanowire are employed to cut and fix the nanowire, respectively. With this strategy, cutting of individual silver nanowires with a diameter from 50 nm to 400 nm is implemented, in which the vibration velocity amplitude of the micro cutting tool’s root is from 18 to 220 mm/s, and the working frequency is about 96.9 kHz and 45.2 kHz, respectively. The dependency of the minimum cutting velocity and optimum cutting velocity range’s lower limit on the AgNW diameter is experimentally clarified. Also, the cutting principle is analyzed, which can well explain the incision morphology and cutting characteristics.     

The nanostructure of soot-in-oil particles and agglomerates from an automotive diesel engine

The characteristics of soot particles and agglomerates of particles extracted from samples of lubricating oil drawn from the sump of a diesel engine have been investigated. The engine was a high pressure common rail, direct injection diesel designed for light duty automotive applications. Soot from the samples was prepared for imaging by sample dilution with heptane, followed by washing in diethyl ether and in some cases, sample centrifugation. The size and shape of agglomerates were defined from measurements of projected length and width allowing for chain contortion. When used, centrifugation is shown to alter the size and shape of agglomerates, increasing the proportion of chain agglomerates and reducing clusters. Without centrifugation, roughly half of the soot in oil exists in long-chain agglomerates with average length of 130 nm and 50 nm in width. Clusters with modest branching account for the remaining 46%. The average aspect ratio (L/W) was of 2.9. The diameter of spherical primary particles that form the agglomerates ranges between 10 and 35 nm grouped in a Gaussian distribution with a mean value of 20.2 nm. All primary particles exhibit an inner core and an outer shell. The inner core is composed by several nuclei of around 4 nm diameter. Inner core is of around 8–15 nm in diameter and outer shell 4–12 nm thick.     

Sensory platform architecture for IN SITU monitoring the thermal comfort in rural environments – The case study at Federal Rural University of Amazonian,Brazil

This research presents an IN SITU sensory platform developed through the integration of air temperature and relative humidity sensors on an ecosystem in order to obtain some thermal characteristic of the rural environments. This sensory platform contains an expert system to detect the behaviors of environmental variables that result in risk or without risk alert to the thermal comfort for human and animal health. For this, the expert system analyses the environmental thermal conditions of the UFRA University, through temperature and humidity index (THI). The THI values estimated (processed) from data of temperature and relative humidity during the year 2012. Four intervals of THI were used to classify human health performance (THI < 74: comfort, 74 ⩽ THI < 79: hot; 79 ⩽ THI ⩽ 84: too hot, and THI > 84: extremely hot), and two intervals to classify animal production (79 ⩽ THI ⩽ 84: dangerous and THI > 84: emergency). The Amazon is located in the equatorial region and has a warm and humid climate that the prevailing mode reveals an alternation of two seasons throughout the year, hot and humid summer and rainy winter. The results that the most critical period occurs between May and October, although it was observed in every day of every year, the THI values during the hottest hours of the day (15:00 pm) range between 75.9 and 86.3, where humans and animals can suffer some degree of thermal stress, affecting negatively both. Therefore, we consider this platform as a good solution for thermal monitoring, which is based on IN SITU measurement technologies for rural environments.     

Dynamic parametric design and feasibility assessment for a high resistance measuring system

A high resistance measuring system (HRMS) is used to measure the surface insulation resistance (SIR) values of the printed circuit board (PCB), and monitor whether a momentary circuit short and/or the case of current slow leakage occur, which will affect the electrical properties of electronic components. This study constructs a dynamic parameter design for optimization of the test parameters of the HRMS in order to obtain robust test results. The optimal test parameters for SIR testing are: 390 ms test time, 100 V test voltage, 100 V, 15 s charge time, and 100 s pause interval. Further investigation is conducted on the impact of the test parameters on the measurement performance.     

Instrumentation and control of a two-stage 4-bed silica gel + water adsorption cooling cum desalination system

This paper presents the instrumentation and control architecture for a laboratory based two-stage 4-bed silica gel + water adsorption system. The system consists of primarily two fluids: refrigerant (water vapour) and heat transfer fluid (water) flowing through various components. Heat input to the system is simulated using multiple heaters and ambient air is used as the heat sink. The laboratory setup incorporates a real time National Instruments (NI) controller to control several digital and analog valves, heaters, pumps and fans along with simultaneous data acquisition from various flow, pressure and temperature sensors. The paper also presents in detail the various automated and manual tasks required for successful operation of the system. Finally the system pressure and temperature dynamics are reported and its performance evaluated for various cycle times.