Customized Measurement System Research Articles

A 3D-Printed Customizable Platform for Multiplex Dynamic Biofilm Studies.

Biofilms are communities of microbes that colonize surfaces. While several biofilm experimental models exist, they often have limited replications of spatiotemporal dynamics surrounding biofilms. For a better understanding dynamic and complex biofilm development, this manuscript presents a customizable platform compatible with off-the-shelf well plates that can monitor microbial adhesion, growth, and associated parameters under various relevant scenarios by taking advantage of 3D printing. The system i) holds any substrate in a stable, vertical position, ii) subjects samples to flow at different angles, iii) switches between static and dynamic modes during an experiment, and iv) allows multiplexing and real-time monitoring of biofilm parameters. Simulated fluid dynamics is employed to estimate flow patterns around discs and shear stresses at disc surfaces. A 3D printed peristaltic pump and a customized pH measurement system for real-time tracking of spent biofilm culture media are equipped with a graphical user interface that grants control over all experimental parameters. The system is tested under static and dynamic conditions with Streptococcus mutans using different carbon sources. By monitoring the effluent pH and characterizing biochemical, microbiological, and morphological properties of cultured biofilms, distinct properties are demonstrated. This novel platform liberates designing experimental strategies for investigations of biofilms under various conditions.

Investigation of Temperature-Induced Errors in XCT Metrology

The presented research shows the time dependent temperature distribution and thermal time constant within a typical industrial X-ray computed tomography (XCT) system used for dimensional metrology. Temperature effects can significantly affect measurement results of XCT scans either by directly changing the dimensions of the measurement object, or by indirectly changing the geometry of XCT scanner. In either case, the effect is not known well enough to be used for correction of measurement results or estimation of measurement uncertainty. In order to determine these effects, traceable temperature measurements were performed with a custom measurement system designed for this application. The influence of temperature fluctuations on length errors was determined by correlation of the measured temperature fluctuations with measurement deviations of a reference standard in repeated CT scans at different X-ray power levels. After experimental determination of X-ray focal spot displacement due to thermal expansion, a simple mathematical model of X-ray source displacement as a function of its temperature was developed and validated for a selected X-ray power level.

Properties of contact pressure induced by manually operated fiber-optic probes.

We assess the properties of contact pressure applied by manually operated fiber-optic probes as a function of the operator, probe contact area, and sample stiffness. First, the mechanical properties of human skin sites with different skin structures, thicknesses, and underlying tissues were studied by in vivo indentation tests. According to the obtained results, three different homogeneous silicone skin phantoms were created to encompass the observed range of mechanical properties. The silicon phantoms were subsequently used to characterize the properties of the contact pressure by 10 experienced probe operators employing fiber-optic probes with different contact areas. A custom measurement system was used to collect the time-lapse of diffuse reflectance and applied contact pressure. The measurements were characterized by a set of features describing the transient and steady-state properties of the contact pressure and diffuse reflectance in terms of rise time, optical coupling, average value, and variability. The average applied contact pressure and contact pressure variability were found to significantly depend on the probe operator, probe contact area, and surprisingly also on the sample stiffness. Based on the presented results, we propose a set of practical guidelines for operators of manual probes.

Development of System SMPSL for Bit Communication

The paper presents development of System SMPSL for binary communication. System SMPSL is computer system for measurement used in the school laboratory. The system is very cheap to assemble the hardware and available software is for free. The system consists of hardware and software parts. The communication is performed using library. The paper describes the basic connections and the source code for creating custom measurement system using a computer. Presented SMPSL system was developed based on mentioned basis.

Effect of retraction speed on adhesion of elastomer fibrillar structures

We studied the dependence of adhesion on retraction speed in elastic fibrillar structures. The evolution of the real contact area and crack propagation speeds at the contact interface was characterized during retraction using a custom measurement system. The experimental results showed an increase in the average crack propagation speed and the rate of change of real contact area during pull-off, for increasing retraction speed. Our results indicate that during pull-off, the critical contact area does not have significant contribution to rate-dependent adhesion, whereas rate of change in the contact area and the crack propagation speed contribute significantly to rate-dependent adhesion.

Extraction of Trap Densities in ZnO Thin-Film Transistors and Dependence on Oxygen Partial Pressure During Sputtering of ZnO Films

Trap densities in the channel layers Dt of ZnO thin-film transistors have been extracted. First, the low-frequency (low-f) capacitance-voltage C-V characteristics are measured using the customized measurement system. Next, the surface potential is calculated from the low-f C-V characteristic, and the surface potential gradient is calculated by applying Gauss's law. Finally, the spatial profile of the electric potential is calculated by applying Poisson equation and carrier density equations, and Dt is extracted. It is found that, generally, the deep states are flatly distributed in the energy gap apart from the conduction band, and the shallow states seem to be the tail states. Moreover, the dependence on the oxygen partial pressure during the sputtering of ZnO films [p(O2)] has been analyzed. It is found that for p(O2) = 0.50 ~ 0.75 Pa, Dt changes little, whereas for p(O2) = 0.17 ~ 0.33 Pa, Dt increases. It is clarified that the abnormal shapes of the current-voltage and low-f C-V characteristics originate from the increase of Dt.

Development of custom measurement system for biomechanical evaluation of independent wheelchair transfers

This study describes a new custom measurement system designed to investigate the biomechanics of sitting-pivot wheelchair transfers and assesses the reliability of selected biomechanical variables. Variables assessed include horizontal and vertical reaction forces underneath both hands and three-dimensional trunk, shoulder, and elbow range of motion. We examined the reliability of these measures between 5 consecutive transfer trials for 5 subjects with spinal cord injury and 12 nondisabled subjects while they performed a self-selected sitting pivot transfer from a wheelchair to a level bench. A majority of the biomechanical variables demonstrated moderate to excellent reliability (r > 0.6). The transfer measurement system recorded reliable and valid biomechanical data for future studies of sitting-pivot wheelchair transfers.We recommend a minimum of five transfer trials to obtain a reliable measure of transfer technique for future studies.

Velocity–Moisture Relationships for Sandy Soils: Experimental Results and Data Analysis

Many techniques have been proposed in recent years for <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">situ</i> soil characterization, and among them, acoustic methods have been revealed to be particularly promising. These methods are based on measurements of the propagation velocities of seismic, sonic, and ultrasonic waves. However, in granular and porous mediums, velocities depend on the state of the saturation of the soil in a complex and not yet fully understood way. In this paper, a refined mathematical model to account for the effects of many soil properties such as porosity, bulk modulus, and pressure on acoustic wave velocity is proposed and investigated. The model has been validated by an experimental comparison between the measured and calculated values of velocities, using a kind of sand of known characteristics. A custom measurement system has been developed and realized for this purpose. The proposed model has potential applications in various areas, including geothermal resource evaluation, petroleum exploration, environmental protection, and archaeological and cultural site protection.

Spatial distribution of RF‐induced E‐fields and implant heating in MRI

The purpose of this study was to assess the distribution of RF-induced E-fields inside a gel-filled phantom of the human head and torso and compare the results with the RF-induced temperature rise at the tip of a straight conductive implant, specifically examining the dependence of the temperature rise on the position of the implant inside the gel. MRI experiments were performed in two different 1.5T MR systems of the same manufacturer. E-field distribution inside the liquid was assessed using a custom measurement system. The temperature rise at the implant tip was measured in various implant positions and orientations using fluoroptic thermometry. The results show that local E-field strength in the direction of the implant is a critical factor in RF-related tissue heating. The actual E-field distribution, which is dependent on phantom/body properties and the MR-system employed, must be considered when assessing the effects of RF power deposition in implant safety investigations.

Motion‐blur characterization on liquid‐crystal displays

Abstract— In this paper, several methods to characterize motion blur on liquid‐crystal displays are reviewed. Based on the assumptions of smooth‐pursuit eye tracking and one‐frame temporal luminance integration, a simple algorithm has been proposed to calculate the normalized blurred edge width (N‐BEW) and motion‐picture response time (MPRT) with a one‐frame‐time moving‐window function to LC temporal step response curves. A custom measurement system with a fast‐eye‐sensitivity‐compensated photodiode has been developed to characterize motion blur based on LC response curves (LCRCs). MPRT values obtained by using the algorithm mentioned above and those from the smooth‐pursuit‐camera methods agree. Perception experiments were conducted to validate the correspondence between the simulated results and actual perceived images by the human eyes. In addition, the insufficiency of MPRT to evaluate motion blur on impulse‐type light‐generation LCDs, by analyzing the measurement results of a scanning backlight LCD, is discussed.