Experimental Measurement System Research Articles

Simultaneous Imaging of Local Calcium and Single Sarcomere Length in Rat Neonatal Cardiomyocytes via Expression of Cameleon-Nano in Z-Discs

In cardiac muscle, contraction is regulated by micromolar concentrations of Ca2+ released from the sarcoplasmic reticulum (SR) (i.e., Ca2+-induced Ca2+ release), resulting in the binding of Ca2+ to troponin C and subsequent formation of cross-bridges. In order to enhance our understanding of cardiac excitation-contraction coupling, we in the present study developed a novel experimental system for simultaneous measurement of local intracellular Ca2+ ([Ca2+]i) and single sarcomere length via expression of yellow cameleon-Nano (i.e., FRET-based ultrasensitive Ca2+ indicator) fused to the C-terminus of α-actinin in Z-discs in primary-cultured rat neonatal cardiomyocytes. In a given sarcomere, the fluorescence emission ratio (YFP/CFP) of the expressed fusion protein varied in response to a change in local [Ca2+]i. Under dual-view microscopy, we simultaneously measured local [Ca2+]i and sarcomere length (the latter defined as the distance between the YFP fluorescence profiles), and found that sarcomere length varied in response to a change in YFP/CFP in various local regions of the myocyte. These results demonstrate that the present experimental system is useful for elucidating cardiac excitation-contraction coupling at the single sarcomere level.

Experimental system for measurement of radiologists' performance by visual search task.

PurposeDetective performance of radiologists for “obvious” targets should be evaluated by visual search task instead of ROC analysis, but visual task have not been applied to radiology studies. The aim of this study was to set up an environment that allows visual search task in radiology, to evaluate its feasibility, and to preliminarily investigate the effect of career on the performance.Materials and methodsIn a darkroom, ten radiologists were asked to answer the type of lesion by pressing buttons, when images without lesions, with bulla, ground-glass nodule, and solid nodule were randomly presented on a display. Differences in accuracy and reaction times depending on board certification were investigated.ResultsThe visual search task was successfully and feasibly performed. Radiologists were found to have high sensitivity, specificity, positive predictive values and negative predictive values in non-board and board groups. Reaction time was under 1 second for all target types in both groups. Board radiologists were significantly faster in answering for bulla, but there were no significant differences for other targets and values.ConclusionWe developed an experimental system that allows visual search experiment in radiology. Reaction time for detection of bulla was shortened with experience.

Relation between gravitational and arm-movement direction in the mechanism of perception in bimanual steering

This paper presents the effects of the opposing directions of gravity relative to right- and left-arm movement in bimanual steering. We developed a simulated steering system that permits independent left- and right-hand steering and torque presentations on a single axis, and independent measurements of the steering force exerted by each hand. In a steering force measurement experiment, left and right system units were mechanically combined to function as a single steering unit. Measurements of the force exerted by the participants with their left and right hands revealed that in human bimanual steering, the arm moving with gravity exerts a larger steering force than the one moving against gravity. In a steering force discrimination experiment, the system was mechanically configured to provide independence in both the function of the left and right steering units and the presentation of different left- and right-side steering torques. Each participant was then asked whether the steering force was felt to be larger on the left or the right during bimanual steering. The results of this experiment showed no difference between the left and the right arm in the discrimination threshold, but did reveal a perceptual bias in which the forces exerted in arm movements with gravity were perceived as being smaller than the forces exerted against gravity. Furthermore, there was no significant difference between the measured force and the force that would be predicted from the obtained perceptual bias.

Experimental Modal Analysis of the Industrial Flat Sewing Machine Based on PolyMax Algorithm

In this paper, the free modal of the industrial flat sewing machine was researched, and the experimental measurement system is established. A modal analysis of industrial flat sewing machine is carried out through the method of single point exciting vibration and multipoint collecting signal. The PolyMax modal parameter identification method is applied to the modal analysis for frequency response function to get steady state diagram and then determine the modal parameters and modal shapes. According to Modal Assurance Criterion (MAC), the credibility of the calculation results is verified, and then modal parameters of industrial flat sewing machine get more reliable in order to provide the reference for further structure optimization and noise reduction of the flat sewing machine.

Assessing the phase retardation in corneal tissues using a femtosecond laser

We developed and validated a versatile test method for precise quantification of phase retardation in corneal tissues using a femtosecond laser. It is based on an experimental system for direct measurement of corneal phase rotation due to corneal birefringence effects using a dual-polarizer, computer-controlled, femtosecond laser design. It also includes a comprehensive analytical model using Jones matrices. The test method presented is used for quantification of phase retardation in corneal tissues by employing the experimental data obtained from corneal phase rotation measurements and using analytical model assessments. The experimental and theoretical results obtained, and thus, the system's high accuracy and repeatability potential for assessing the corneal phase retardation are validated using control phase retardation evaluation.

Research on thermal deformation of large-scale computer numerical control gear hobbing machines

Research on thermal deformation of large-scale computer numerical control (CNC) hobbing machines is on the purpose of obtaining the law of thermal deformation of gear hobbing machines to improve machining precision. According to the structure characteristics of hobbing machines, this paper presents a novel computing model of thermal deformation based on the theory of the thermal expansion deformation of metallic materials, the extensional beam theory, non-uniform temperature distribution of the Euler-Bernoulli beam and Kirchhoff theory of plane-section assumption. Then, the coupling theory of axial and bending deformation of hobbing machines based on the deformation element and equilibrium element method is proposed. The experimental measurement system and platform for thermal deformation of gear hobbing machines is established. The temperature and displacement data of thermal deformation of a certain type gear hobbing machine is analyzed, which has demonstrated the law of thermal deformation of hobbing machines. The locus curves for overall displacement error of cutting points and teeth trace error are obtained. Comparing deformation theory and experimental data, the relative error is lower than 5%, which verifies the computing model proposed by this paper, and shows the research method has great significance for structural optimization, local temperature control, and prediction and compensation for thermal deformation error of gear hobbing machines.

Calibration method for line-structured light multi-vision sensor based on combined target

Calibration is one of the most important technologies for line-structured light vision sensor. The existing calibration methods depend on special calibration equipments, whose accuracy determines the calibration accuracy. It is difficult to meet the requirements of universality and field calibration with those methods. In order to solve these problems, a new calibration method based on the combined target for line-structured light multi-vision sensor is proposed. Each line-structured light multi-vision sensor is locally calibrated by combined target with high precision. On the basis of global calibration principle and the characteristics of the combined target, global calibration and local calibration are unified. The unification avoids the precision decrement caused by coordinate transformation. And the occlusion problem of 3D reference objects can be avoided. An experimental system for 3D multi-vision measurement is set up with two sets of vision sensor and its calibration matrix is obtained. To improve the calibration accuracy, the method of acquiring calibration points with high precision and error factors in calibration are analyzed. After being calibrated, the experimental system is finally tested through a workpiece measurement experiment. The repeatability of this system is 0.04 mm, and it proves that the proposed calibration method can obtain high precision. Moreover, by changing the structure of the combined target, this calibration method can adapt to the different multi-vision sensors, while the accuracy of the combined target is still guaranteed. Thus, this calibration method has the advantages of universality and field calibration.

A Sampling Train for Rapid Measurement of Regional Lung Deposition

An experimental system for rapid measurement of regional lung deposition of Di-2-ethylhexyl sebacate (DEHS) aerosol particles was established in the present study. The principal goal was to identify the most relevant components of the sampling train and the proper instruments to be employed. After completing the search for an optimal sampling train and instruments, a human subject test was performed. Overall, the sampling train consisted of a mouthpiece, flow meter, and particle counter. The mouthpiece was attached to a Fleisch pneumotachograph. Several TSI condensation particle counters (CPCs), a PC-LabCard and a personal computer were employed to measure and record the counts of test particles at 100 Hz. A cylinder-piston breathing machine was built to generate a series of “standard” breathing patterns. For non-human subject tests, an acrylic tube, 5 cm diameter × 60 cm length, packed with a piece of 100 ppi foam disks was used as a substitute for the human respiratory tract. The optimal sampling train was determined to be a 1TH Fleisch pneumotachograph with a CPC model 3025A because of its short response time and low flow fluctuation. A healthy non-smoking man volunteered to be the subject, and was asked to follow breathing patterns generated by a cylinder-piston breathing machine. The local deposition efficiency was calculated for 1 μm DEHS particles of each 50 cm 3 volumetric region. The deposition data showed a good agreement with previous studies. Compared to the conventional bolus system, the advantage of the rapid measurement system developed in this work is its simplicity, low exposure, and high efficiency.

Experimental infrared measurements for hydrocarbon pollutant determination in subterranean waters

Subterranean waters are often polluted by industrial and anthropic effluents that are drained in subsoil. To prevent and control pollution, legislations of different developed countries require an online monitoring measurement, especially for detecting organic solvents (chlorinated and unchlorinated ones). Online measurements include both real-time and no real-time measurements. In general, it is difficult to implement real-time measurements in stricto sensu for online acquisitions on aqueous effluents since they need to be processed by a modeling. This research presents an experimental measurement system based on infrared (IR) spectroscopy for aqueous effluents containing hydrocarbons and capable of displaying excellent values of pollutant concentrations even in instable conditions; the system is able to detect pollutants either in laminar or turbulent flow. The results show the possibility of avoiding the use of "Pitot tube" that is employed to create a stagnation point in order to convert kinetic energy into potential one. This conversion allows the transformation of a turbulent flow in a laminar flow making easy measurement of pollutants included in an aqueous effluent. Obviously, "Pitot tube" is also used for other fluid effluents. The obtained results have been compared with those produced by means of sophisticated IR instrumentation for laboratory applications.

Simultaneous Electroencephalography, Real-time Measurement of Lactate Concentration and Optogenetic Manipulation of Neuronal Activity in the Rodent Cerebral Cortex

Although the brain represents less than 5% of the body by mass, it utilizes approximately one quarter of the glucose used by the body at rest(1). The function of non rapid eye movement sleep (NREMS), the largest portion of sleep by time, is uncertain. However, one salient feature of NREMS is a significant reduction in the rate of cerebral glucose utilization relative to wakefulness(2-4). This and other findings have led to the widely held belief that sleep serves a function related to cerebral metabolism. Yet, the mechanisms underlying the reduction in cerebral glucose metabolism during NREMS remain to be elucidated. One phenomenon associated with NREMS that might impact cerebral metabolic rate is the occurrence of slow waves, oscillations at frequencies less than 4 Hz, in the electroencephalogram(5,6). These slow waves detected at the level of the skull or cerebral cortical surface reflect the oscillations of underlying neurons between a depolarized/up state and a hyperpolarized/down state(7). During the down state, cells do not undergo action potentials for intervals of up to several hundred milliseconds. Restoration of ionic concentration gradients subsequent to action potentials represents a significant metabolic load on the cell(8); absence of action potentials during down states associated with NREMS may contribute to reduced metabolism relative to wake. Two technical challenges had to be addressed in order for this hypothetical relationship to be tested. First, it was necessary to measure cerebral glycolytic metabolism with a temporal resolution reflective of the dynamics of the cerebral EEG (that is, over seconds rather than minutes). To do so, we measured the concentration of lactate, the product of aerobic glycolysis, and therefore a readout of the rate of glucose metabolism in the brains of mice. Lactate was measured using a lactate oxidase based real time sensor embedded in the frontal cortex. The sensing mechanism consists of a platinum-iridium electrode surrounded by a layer of lactate oxidase molecules. Metabolism of lactate by lactate oxidase produces hydrogen peroxide, which produces a current in the platinum-iridium electrode. So a ramping up of cerebral glycolysis provides an increase in the concentration of substrate for lactate oxidase, which then is reflected in increased current at the sensing electrode. It was additionally necessary to measure these variables while manipulating the excitability of the cerebral cortex, in order to isolate this variable from other facets of NREMS. We devised an experimental system for simultaneous measurement of neuronal activity via the elecetroencephalogram, measurement of glycolytic flux via a lactate biosensor, and manipulation of cerebral cortical neuronal activity via optogenetic activation of pyramidal neurons. We have utilized this system to document the relationship between sleep-related electroencephalographic waveforms and the moment-to-moment dynamics of lactate concentration in the cerebral cortex. The protocol may be useful for any individual interested in studying, in freely behaving rodents, the relationship between neuronal activity measured at the electroencephalographic level and cellular energetics within the brain.

Simultaneous Electroencephalography, Real-time Measurement of Lactate Concentration and Optogenetic Manipulation of Neuronal Activity in the Rodent Cerebral Cortex

Although the brain represents less than 5% of the body by mass, it utilizes approximately one quarter of the glucose used by the body at rest1. The function of non rapid eye movement sleep (NREMS), the largest portion of sleep by time, is uncertain. However, one salient feature of NREMS is a significant reduction in the rate of cerebral glucose utilization relative to wakefulness2-4. This and other findings have led to the widely held belief that sleep serves a function related to cerebral metabolism. Yet, the mechanisms underlying the reduction in cerebral glucose metabolism during NREMS remain to be elucidated. One phenomenon associated with NREMS that might impact cerebral metabolic rate is the occurrence of slow waves, oscillations at frequencies less than 4 Hz, in the electroencephalogram5,6. These slow waves detected at the level of the skull or cerebral cortical surface reflect the oscillations of underlying neurons between a depolarized/up state and a hyperpolarized/down state7. During the down state, cells do not undergo action potentials for intervals of up to several hundred milliseconds. Restoration of ionic concentration gradients subsequent to action potentials represents a significant metabolic load on the cell8; absence of action potentials during down states associated with NREMS may contribute to reduced metabolism relative to wake. Two technical challenges had to be addressed in order for this hypothetical relationship to be tested. First, it was necessary to measure cerebral glycolytic metabolism with a temporal resolution reflective of the dynamics of the cerebral EEG (that is, over seconds rather than minutes). To do so, we measured the concentration of lactate, the product of aerobic glycolysis, and therefore a readout of the rate of glucose metabolism in the brains of mice. Lactate was measured using a lactate oxidase based real time sensor embedded in the frontal cortex. The sensing mechanism consists of a platinum-iridium electrode surrounded by a layer of lactate oxidase molecules. Metabolism of lactate by lactate oxidase produces hydrogen peroxide, which produces a current in the platinum-iridium electrode. So a ramping up of cerebral glycolysis provides an increase in the concentration of substrate for lactate oxidase, which then is reflected in increased current at the sensing electrode. It was additionally necessary to measure these variables while manipulating the excitability of the cerebral cortex, in order to isolate this variable from other facets of NREMS. We devised an experimental system for simultaneous measurement of neuronal activity via the elecetroencephalogram, measurement of glycolytic flux via a lactate biosensor, and manipulation of cerebral cortical neuronal activity via optogenetic activation of pyramidal neurons. We have utilized this system to document the relationship between sleep-related electroencephalographic waveforms and the moment-to-moment dynamics of lactate concentration in the cerebral cortex. The protocol may be useful for any individual interested in studying, in freely behaving rodents, the relationship between neuronal activity measured at the electroencephalographic level and cellular energetics within the brain.

Improved phase generated carrier demodulation algorithm for eliminating light intensity disturbance and phase modulation amplitude variation

In this paper we propose a novel, improved, phase generated carrier (PGC) demodulation algorithm based on the PGC-differential-cross-multiplying approach (PGC-DCM). The influence of phase modulation amplitude variation and light intensity disturbance (LID) on traditional PGC demodulation algorithms is analyzed theoretically and experimentally. An experimental system for remote no-contact microvibration measurement is set up to confirm the stability of the improved PGC algorithm with LID. In the experiment, when the LID with a frequency of 50 Hz and the depth of 0.3 is applied, the signal-to-noise and distortion ratio (SINAD) of the improved PGC algorithm is 19 dB, higher than the SINAD of the PGC-DCM algorithm, which is 8.7 dB.

Identification of the Jiles-Atherton Model Parameters Using Simulated Annealing Method

This paper presents a method and the experimental measurement system for the determination of Jiles-Atherton model parameters of the 30ZH120 electrical steel sheet. The paper utilizes Epstein Square devices to proceed with the experiment and measurement on a group of hysteresis loops of some certain transformers which use the 30ZH120 electrical steel sheet under two different lap ways. The approach relies on the simulated annealing optimization method in order to minimize the error between the measured and modeled hysteresis curves and yield the best five Jiles-Atherton model parameters. A convenient program, based on the Simulink platform, that can identify the J-A model parameters automatically from the experimental saturated hysteresis loop which is used to model the nonlinear characteristics of the electrical steel sheet, is developed. Research shows that the simulated annealing optimization method gets satisfactory results.

UV differential optical absorption method for measuring sulfur content in coal

Determining the sulfur content in coal rapidly and accurately can provide a technical basis for the enterprises and the environmental administration departments. A novel method for measuring the sulfur content in coal based on UV differential optical absorption is presented in this paper. However, compared with the applications in atmosphere monitoring, the UV differential optical absorption spectroscopy (DOAS) for the sulfur content measurement in coal has the problems that the concentration range of SO2 in the flue gas is wider and the optical path-length of the gas cell is shorter. To solve these problems, an improved DOAS algorithm based on a finite impulse response (FIR) filter and a nonlinear compensation technique is proposed. An experimental measurement system based on the modified DOAS is designed and established. The standard SO2 gas and five kinds of standard coals are experimentally tested. Theoretical and experimental results show that the lower detection limit of the system is better than 0.014%, and the repeatability of the measurement system fairly meets the national standard of China. The system has advantages of low maintenance and shorter measurement duration (4 min).

Experimental Investigation on Underwater Opto-Acoustic Communication

The underwater opto-acoustic communication system for directional acoustic communication between an in-air platform and a submerged platform operating is important. The paper presents a new method to solve this problem with opto-acoustic technology, which combines high-energy laser, the opto-acoustic transmitter that optical energy is converted to acoustic energy at the water surface. The laser-based transmitter provides a versatile method for generating underwater sound. The acoustic pressure is linearly proportional to the laser power. The paper designed an experimental measurement system for the opto-acoustic communication. It made experiments for study on the waveform and spectrum characteristics of opto-acoustic signals. The paper also discuss the acoustic wave after optical breakdown in water with Nd:YAG laser pulses. The opto-acoustic signals can controll by adjusting the laser's parameters. The conclusion is that the opto-acoustic communication has some technical advantages. This system presents a change in the way communicational from the air.

Benchmark tests for a Formula SAE Student car prototyping

Abstract Aerodynamic characteristics of a vehicle are important elements in its design and construction. A low drag coefficient brings significant fuel savings and increased engine power efficiency. In designing and developing vehicles trough computer simulation process to determine the vehicles aerodynamic characteristics are using dedicated CFD (Computer Fluid Dynamics) software packages. However, the results obtained by this faster and cheaper method, are validated by experiments in wind tunnels tests, which are expensive and were complex testing equipment are used in relatively high costs. Therefore, the emergence and development of new low-cost testing methods to validate CFD simulation results would bring great economic benefits for auto vehicles prototyping process. This paper presents the initial development process of a Formula SAE Student race-car prototype using CFD simulation and also present a measurement system based on low-cost sensors through which CFD simulation results were experimentally validated. CFD software package used for simulation was Solid Works with the FloXpress add-on and experimental measurement system was built using four piezoresistive force sensors FlexiForce type.

Numerical and experimental analysis for the skew phenomena on the flexible belt and roller contact systems

The thin, flexible, flat belt system is frequently employed for power transmission, conveyor systems, and various manufacturing process equipments, such as printers, elevators, and automated teller machines. In general, some critical problems can happen during operation, since a thin flexible belt on rollers can easily skew. This is especially serious for high-speed belt operations. In this skewed situation, due to possible relative roller misalignment, roller deflection, and/or belt non-uniformity itself, a thin flexible belt can move along the perpendicular direction to the travelling direction. In this investigation, an efficient analysis method for simulating skewing phenomena of thin flexible belt systems is presented using the complete integration of large deformable finite element methods and multibody dynamics. A 4-node shell element is used to describe a thin flexible belt and two rigid cylindrical bodies describe the roller. Each cylindrical body is fixed with a pin joint and the positions of the rollers are adjusted to impose a tension to thebelt. For the interactions between the belt and the rollers, an efficient contact search algorithm based on a compliant contact force model is presented in this study. The contact search algorithm is composed of a pre-search and a detailed search to identify points of contact between the belt and the rollers. In the pre-search, a simple algorithm is used to identify lines on the belt that are close enough to the rollers that there might potentially be contact between them. The detailed search is performed by making efficient two-dimensional (2D) comparisons of the cross-section of the roller with a 2D projection of the belt lines identified in the pre-search. Afterwards, the contact force is generated by a compliant force model that uses a stick–slip frictional algorithm. The simulation model is validated against experimental measurement systems for thin flexible belt and rollers. It shows a good agreement with the numerical results. Furthermore CPU time with commercial software ANSYS Workbench is compared to check the performance of the algorithm. The proposed method is more than 10 times faster compared with ANSYS Workbench.

Study on Calibration for Parameters of Johnson-Cook Constitutive Equation

Procedure of determination for parameters of Johnson-Cook model, which is widely used in numerical computation and design for manufacture process, is made. The paper describes fundamental investigation of Johnson-Cook constitutive equation firstly, then quasi-static compression experiment MTS is reviewed briefly, and dynamic compression experiment SHPB is studied from all aspects of experimental principle of one dimension stress wave, experimental measurement system to experimental data handling. In the end methods of Calibration for A, B, n, C and m of Johnson-Cook constitutive model’s parameters are discussed in details.

New experimental device to test the dynamic behavior of fiber assemblies and fibrous composite structures with a focus on larger industrial‐scale‐like samples

AbstractThis article focuses on the development of an experimental measurement system intended for dynamic mechanical analysis (DMA) of fiber structures. First, a short review of DMA testing procedures is given, followed by an analysis of particularities of DMA application to fibers and rope assemblies. The necessity of developing a dedicated device for fiber assembly and rope applications is pointed out, as the commercial DMA testing devices available are intended for shorter specimens. Thus, the article insists on the underlying necessity to come up with a measurement device for much longer fiber specimens and a testing procedure therewith. Then the article presents the main concepts of the new device and its operation. Three different operating modes are presented with explanations of their functioning, their particularities, and the interest for rope testing. After that, the implementation of the testing device prototype is presented, describing the mechanical set up, electromagnetic elements, power and acquisition circuitry and software. At last, preliminary experimental results are provided demonstrating the feasibility of this solution and indications concerning the potential future developments of this kind of rope testing systems are given. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Accelerometry for the motion analysis of the lateral plane of the human body during gait

The measurement of a particular limb in the human body is an important task in many applications. Human behavior understanding typically involves human body posture analysis or estimation, as well as the generated corresponding gestures. This behavioral characterization makes it possible to analyze, interpret and animate human actions and, therefore, enables us to use some experimental methodologies. The present aims to contribute to this field by presenting the development of an experimental measurement system for human gait using accelerometry (an accelerometer network distributed on the body). When the subject walks, the system captures and processes the events and determines the angles of the limb. For results assessment, a virtual body model is presented in real-time motion, with data being stored in a database for future evaluations and analyses. The system proposed in this paper showed an average error of 3.1°, has low cost, high accuracy and is suitable for a wide range of applications.