Simple Measurement Technique Research Articles

Getting the most from venous occlusion plethysmography: proposed methods for the analysis of data with a rest/exercise protocol.

BackgroundVenous occlusion plethysmography is a simple yet powerful technique for the non-invasive measurement of blood flow. It has been used extensively in both the experimental and clinical settings. The underlying rationale is that when venous outflow from an extremity is occluded, any immediate increase in volume of this compartment must originate from the on-going arterial inflow. Mercury-in-silastic strain gauges are typically used to measure these volume changes, the rates of which are directly proportional to blood flow.ResultsWhen using a simple rest/exercise protocol to provide a local or systemic metabolic stimulus to increase blood flow, current methods for analysing the data obtained are often rather simplistic, solely considering the mean increment in blood flow induced by exercise. Previous methodological considerations have focused mainly on issues of reproducibility and accuracy (for instance, by comparing unilateral and/or bilateral measurements) but rarely on what the recorded traces may actually mean.ConclusionsIn this methodological manuscript, we suggest a more detailed approach to processing venous occlusion plethysmography data, one which could provide additional physiological information. Six parameters are described, all of which are easily derived from a simple and reproducible experimental rest/exercise venous occlusion plethysmography protocol.

A New Method of Design and Verification of Digital Silicon Gyroscopes Closed-Loop Driving System Based on MicroBlaze

The article brings out a digital silicon gyroscopes closed-loop driving system using the phase relationship of the input driving signal and the signal of the forced motion of the mass block in sensor structure based on analyzing the working principle and phase characters of digital silicon gyroscopes. We make a low-cost, simple and high precision measurement technique for resonant frequency of silicon micro-machinery gyroscopes by the whole digital locked loop system designed with MicroBlaze method. Dichotomy and Fourier transform spectrometry method constitute the algorithm of the system and the solution precision can be determined by the number of the times of approximation. Under the control of the MicroBlaze softcore, the system realizes the realization of the digital signal, the high speed frequency transformation, the acquisition of mass block response signal and the calculation of phase difference. Lastly, each module of the system and the whole system are simulated, the whole system is approved on the test broad.

The Incidence of Delirium at the Postoperative Intensive Care Unit in Adult Patients.

In this study, we aimed to determine the risk factors and the incidence of delirium in patients who were followed postoperatively in our surgical intensive care unit for 24 h using the confusion assessment method (CAM). After obtaining approval from the ethics committee, 250 patients were included in the study. Patients who were operated under general anaesthesia or regional anaesthesia and followed in the surgical intensive care unit were evaluated by the Ramsay Sedation Scale on the first postoperative day. CAM was applied to the patients who had a Ramsey Sedation Score of ≤4. Patients' age, gender, American Society of Anesthesiologists (ASA) scores, preoperative risk factors, type of anaesthesia, operation time, intra-operative procedures, pain scores evaluated by the visual analogue scale (VAS) and postoperative analgesia methods were recorded. The incidence of delirium was found to be 18.4%. The average age of patients who developed delirium was greater than the others (68.8±12.7 and 57.6±12, p=0.001, respectively). It was observed that a one-unit increase in the ASA score resulted in a 3.3-fold increase in the risk of delirium. The incidence of delirium in patients undergoing regional anaesthesia was 34.6%, whereas it was 16.5% in patients receiving general anaesthesia (p=0.024). The existence of preoperative diabetes mellitus (DM) and chronic obstructive pulmonary disease (COPD) was shown to improve the development of delirium (p<0.05). Delirium incidence was significantly higher in patients who were administered meperidine for postoperative analgesia (p=0.013). The VAS scores of patients who developed delirium were found to be significantly higher (p=0.006). As a result, we found that older age, high ASA score, preoperative DM and COPD are important risk factors for the development of delirium. Regional anaesthesia, high postoperative pain scores and meperidine use were observed to be associated with the development of delirium. In the postoperative period, addition of CAM, a simple measurement technique, to the daily follow-up forms can provide the early recognition of delirium, which is often underdiagnosed. We think that identification and prevention of effective risk factors have the primary importance for postoperative delirium.

First Detection of Single-Electron Charging of the Floating Gate of NAND Flash Memory Cells

This letter provides the first direct experimental detection of single-electron charging of the floating gate of a mainstream Flash memory cell. The detection is shown to be easily achievable through conventional and very simple measurement techniques on state-of-the-art technologies. Results represent a milestone for the investigation of the physics of Flash memory operation, opening the possibility for direct analyses of the piling up of single electrons in the floating gate during cell programming.

Real-Time FFT Analysis for Interferometric Sensors Multiplexing

In this paper, a theoretical and experimental study of two interferometric sensor multiplexing schemes has been carried out by means of the fast Fourier transform (FFT) analysis. This study addresses one of the main drawbacks of photonic crystal fiber (PCF) sensors, that is, its multiplexing capability. Using a commercial optical interrogator combined with a simple FFT measurement technique, the simultaneous real-time monitoring of several PCF sensors is achieved. A theoretical analysis has been performed where simulations matched with the experimental results. For the experimental verification, highly birefringent (HiBi) fiber sections that operated as sensing elements were multiplexed and tested in two configurations. Due to the FFT analysis, both multiplexing schemes can be properly interrogated by monitoring the FFT phase change at the characteristic spatial-frequency of each sensor. For this purpose, a commercial interrogator and a custom Matlab program were used for computing the FFT and for monitoring the FFT phase change in real time (1 Hz).

Metrology Needs for Predicting Concrete Pumpability

With the increasing use of pumping to place concrete, the development and refinement of the industry practice to ensure successful concrete pumping are becoming important needs for the concrete construction industry. To date, research on concrete pumping has been largely limited to a few theses and research papers. The major obstacle to conduct research on concrete pumping is that it requires heavy equipment and large amounts of materials. Thus, developing realistic and simple measurement techniques and prediction tools is a financial and logistical challenge that is out of reach for small research labs and many private companies in the concrete construction industry. Moreover, because concrete pumping involves the flow of a complex fluid under pressure in a pipe, predicting its flow necessitates detailed knowledge of the rheological properties of concrete, which requires new measurement science. This paper summarizes the technical challenges associated with concrete pumping and the development in concrete pumping that have been published in the technical literature and identifies future research needed for the industry to develop best practices for ensuring successful concrete pumping in the field.

A simple method of measuring tibial tubercle to trochlear groove distance on MRI: description of a novel and reliable technique.

Tibial tubercle-trochlear groove (TT-TG) distance is a variable that helps guide surgical decision-making in patients with patellar instability. The purpose of this study was to compare the accuracy and reliability of an MRI TT-TG measuring technique using a simple external alignment method to a previously validated gold standard technique that requires advanced software read by radiologists. TT-TG was calculated by MRI on 59 knees with a clinical diagnosis of patellar instability in a blinded and randomized fashion by two musculoskeletal radiologists using advanced software and by two orthopaedists using the study technique which utilizes measurements taken on a simple electronic imaging platform. Interrater reliability between the two radiologists and the two orthopaedists and intermethods reliability between the two techniques were calculated using interclass correlation coefficients (ICC) and concordance correlation coefficients (CCC). ICC and CCC values greater than 0.75 were considered to represent excellent agreement. The mean TT-TG distance was 14.7mm (Standard Deviation (SD) 4.87mm) and 15.4mm (SD 5.41) as measured by the radiologists and orthopaedists, respectively. Excellent interobserver agreement was noted between the radiologists (ICC 0.941; CCC 0.941), the orthopaedists (ICC 0.978; CCC 0.976), and the two techniques (ICC 0.941; CCC 0.933). The simple TT-TG distance measurement technique analysed in this study resulted in excellent agreement and reliability as compared to the gold standard technique. This method can predictably be performed by orthopaedic surgeons without advanced radiologic software. II.

Quantitative Angle-Resolved Small-Spot Reflectance Measurements on Plasmonic Perfect Absorbers: Impedance Matching and Disorder Effects

Plasmonic devices with absorbance close to unity have emerged as essential building blocks for a multitude of technological applications ranging from trace gas detection to infrared imaging. A crucial requirement for such elements is the angle independence of the absorptive performance. In this work, we develop theoretically and verify experimentally a quantitative model for the angular behavior of plasmonic perfect absorber structures based on an optical impedance matching picture. To achieve this, we utilize a simple and elegant k-space measurement technique to record quantitative angle-resolved reflectance measurements on various perfect absorber structures. Particularly, this method allows quantitative reflectance measurements on samples where only small areas have been nanostructured, for example, by electron-beam lithography. Combining these results with extensive numerical modeling, we find that matching of both the real and imaginary parts of the optical impedance is crucial to obtain perfect absorption over a large angular range. Furthermore, we successfully apply our model to the angular dispersion of perfect absorber geometries with disordered plasmonic elements as a favorable alternative to current array-based designs.

Direct Measurements of Drag Forces in C. elegans Crawling Locomotion

With a simple and versatile microcantilever-based force measurement technique, we have probed the drag forces involved in Caenorhabditis elegans locomotion. As a worm crawls on an agar surface, we found that substrate viscoelasticity introduces nonlinearities in the force-velocity relationships, yielding nonconstant drag coefficients that are not captured by original resistive force theory. A major contributing factor to these nonlinearities is the formation of a shallow groove on the agar surface. We measured both the adhesion forces that cause the worm’s body to settle into the agar and the resulting dynamics of groove formation. Furthermore, we quantified the locomotive forces produced by C. elegans undulatory motions on a wet viscoelastic agar surface. We show that an extension of resistive force theory is able to use the dynamics of a nematode’s body shape along with the measured drag coefficients to predict the forces generated by a crawling nematode.

MEASUREMENT OF STRUCTURE-BORNE NOISE FROM ROAD INPUT IN A MOTOR VEHICLE CABIN

Vehicle interior noise holds paramount aspect in determining its overall quality since it affects the level of acoustic comfort of the passengers. From various methods of measuring noise inside a vehicle cabin, a measurement technique has been developed in this project to measure the interior vehicle noise from road input. This project proposes a simple noise measurement technique which is direct noise measurement when test vehicle is running on the dynamometer, road and airborne noise measurement. The comparison between measured Sound Pressure Level (SPL) from road input and dynamometer input shows the contribution of structure-borne noise due to tire-road interactions and aerodynamic excitation. The comparison between measured SPL for total interior noise (at stationary condition) and SPL for road input shows the contribution of noise from road input, vehicle suspension system, and aerodynamic excitation. British Standard BS 6086:1981 on method of measurement of noise inside motor vehicle had been followed closely to ensure high accuracy of results obtained from the direct noise measurements method.

Maximum probing depth of low-energy photoelectrons in an amorphous organic semiconductor film

The attenuation length (AL) of low energy photoelectrons inside a thin film of a π-conjugated organic semiconductor material, 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole), was investigated using ultraviolet photoelectron spectroscopy (UPS) and photoelectron yield spectroscopy (PYS) to discuss their probing depth in amorphous organic thin films. The present UPS results indicated that the AL is 2–3nm in the electron energy range of 6.3–8.3eV with respect to the Fermi level, while the PYS measurements which collected the excited electrons in a range of 4.5–6eV exhibited a longer AL of 3.6nm. Despite this still short AL in comparison to a typical thickness range of electronic devices that are a few tens of nm-thick, the photoemission signal penetrating through further thicker (18nm) organic film was successfully detected by PYS. This fact suggests that the electronic structures of “buried interfaces” inside practical organic devices are accessible using this rather simple measurement technique.

Ingredients for sensors science

This paper is a contribution to the improvement of the communication of results in sensors among the researchers active in the field.First, it provides a set of definition for a clearer identification of the existing types of sensors. These definitions lead to the representation of any sensor as a composition of basic parts each characterized by a proper sensitivity concurring to the total sensitivity of the device.Sensitivity and resolution are generally recognized as important parameters to describe the properties of sensors. Here we suggest that without a declaration of the sensor operating point (the measurand value and its neighbour) sensitivity and resolution become inadequate concepts hindering the comparison between sensors and, ultimately, the reproducibility of the results.Furthermore, being the sensor resolution strongly related to the signal to noise level, two simple and easy implementable techniques for noise measurement and interpretation are presented and commented.

Interferometric measurement of the internal field of lithium niobate without high-voltage electric field poling

A simple interferometric technique for measurement of the internal field (IF) in a ferroelectric crystal has been proposed. This technique has several advantages over the other methods used previously for evaluation of IFs in ferroelectric crystals. Here, the electro-optic property of lithium niobate is exploited for quantitative analysis of its IF. The strength of IF obtained using this technique lies within the range given in the literature. However, at frustrated domain inversion state, the measured value of IF shows a reduced value. A possible reason for this reduction based on the defect model has been discussed.

New approaches to measuring biochar density and porosity

It is clear that the density and porosity of biochar will impact its mobility in the environment, its interaction with the soil hydrologic cycle, and its suitability as an ecological niche for soil microorganisms. However, the wide range of biochar pore sizes complicates biochar porosity characterization, making it challenging to find methods appropriate to connect the fundamental physical properties of density and porosity to environmental outcomes. Here, we report the use of two fast, simple density measurement techniques to characterize biochar density and porosity. We measured biochar skeletal density by helium pycnometry and envelope density by displacement of a dry granular suspension. We found that biochar skeletal density ranged from 1.34 g cm−3 to 1.96 g cm−3, and increased with pyrolysis temperature. Biochar envelope density ranged from 0.25 g cm−3 to 0.60 g cm−3, and was higher for wood biochars than grass biochars—a difference we attribute to plant cell structures preserved during pyrolysis. We compared the pore volumes measured by pycnometry with those measured by nitrogen gas sorption and mercury porosimetry. We show that biochar pore volumes measured by pycnometry are comparable to the values obtained by mercury porosimetry, the current benchmark method. We also show that the majority of biochar pore volume is in macropores, and thus, is not measured by gas sorption analysis. These fast, simple techniques can now be used to study the relationship between biochar's physical properties and its environmental behaviors.

Apparent Viscosity Direct from Marsh Funnel Test

Accurate and simple techniques for measurement of fluid rheological properties are important for field operations in the oil industry. Marsh Funnels are popular quality-control tools used in the field for drilling fluids and they offer a simple, practical alternative to viscosity measurement. In the normal measurements, a single point (drainage time) is used to determine an average viscosity; little additional information is extracted regarding the non-Newtonian behavior of the fluid.Here, a new model is developed and used to determine the rheological properties of drilling muds and other non-Newtonian fluids using data of fluid density and drainage time collected from a Marsh Funnel as a function of viscosity. The funnel results for viscosity compare favorably to the values obtained from a commonly-used Fann 35 viscometer. Different quantities of bentonite, barite and other additives which have been used to prepare many samples. Empirical equations are obtainedμapp. = ρ (t – 28) and μapp. = -0.0118t2 + 1.6175t - 32.168,where apparent viscosity (μapp.) in (cp), Marsh funnel time (t) in seconds and the density (ρ) in gm/cm3.

Acoustic impedance rhinometry (AIR): a technique for monitoring dynamic changes in nasal congestion

We describe a simple and inexpensive method for monitoring nasal air flow resistance using measurement of the small-signal acoustic input impedance of the nasal passage, similar to the audiological measurement of ear drum compliance with acoustic tympanometry. The method requires generation of a fixed sinusoidal volume–velocity stimulus using ear-bud speakers, and an electret microphone to monitor the resultant pressure fluctuation in the nasal passage. Both are coupled to the nose via high impedance silastic tubing and a small plastic nose insert. The acoustic impedance is monitored in real-time using a laptop soundcard and custom-written software developed in LabView 7.0 (National Instruments). The compact, lightweight equipment and fast time resolution lends the technique to research into the small and rapid reflexive changes in nasal resistance caused by environmental and local neurological influences. The acoustic impedance rhinometry technique has the potential to be developed for use in a clinical setting, where the need exists for a simple and inexpensive objective nasal resistance measurement technique.

Simple Lock-In Technique for Thickness Measurement of Metallic Plates

Eddy-current techniques are largely employed for measurements of thickness and conductivity of metallic plate, and layers. In these measurements, an alternating voltage is applied to a magnetizing coil placed over the metallic plate and its impedance is measured as a function of the frequency. The eddy currents induced into the plate produce a magnetic field that couples with the coil, and the resulting impedance depends on the metal plate conductance and thickness. It has been found that the phase of the inductance is an especially useful parameter. In this paper, we propose a lock-in method to extract the phase signature and to relate it to the plate conductance and thickness and to the thickness of possible insulating coatings. The equipment needed for the measurement is simple and inexpensive if compared to impedance meters usually employed.

Simple Technique for Measurement of Complex Permittivity and Detection of Small Permittivity Change Using Partially Open Cavity

This letter presents a measurement methodology of the complex permittivity of liquid using a partially open cavity in narrow band. The partially open cavity (POC) can measure dielectric small changes caused by the temperature variation of the liquid inside the cavity as well. Using the resonance frequency and unloaded quality factor of the proposed POC, the complex permittivity is evaluated. The apertures on the walls of the cavity are designed to circulate the liquid inside to outside of the POC and located at the corner area of the cavity to minimize the disturbance of field distribution at the dominant mode. The results measured by the proposed POC were compared with those by the conventional open-ended probe and Cole-Cole equation. The POC showed better performance in measuring small dielectric constant changes than the open-ended probe.

Two-perspective fluorescence analysis of droplets creeping down a tilted plate

Many experimental techniques have been developed and applied to investigate hydrodynamics of liquid films and single droplets on solid substrates. A simple but reliable measurement technique has been recently proposed to quantify thickness and apparent contact angles of droplets and rivulets (Hagemeier et al. Exp Fluids 52(2):361–374, 2012). However, this technique leads to ambiguities for any contact angle exceeding 90°. An improved version has thus been derived to solve the most important issues associated with the original method. For this purpose, top and sideways two-perspective images are acquired simultaneously, both relying on fluorescence. Analyzing the data obtained from both views, a correlation between fluorescence intensity and droplet shape can be derived. Furthermore, advancing and receding contact angles can be determined in this manner. A new and particularly important feature of the improved technique is the estimation of the contact line velocity at various locations, all around the moving droplet. The in-plane velocity components show a clear dependency on the Bond number and on the position around the droplet circumference.

Measurement of the flexoelectric response in ferroelectric and relaxor polymer thin films

We report measurements of the flexoelectric response (electric polarization induced by a strain gradient) in thin films of both ferroelectric and relaxor forms of vinylidene fluoride polymers. By using a simple cantilever measurement technique, while monitoring remanent polarization through the pyroelectric response, we are able to measure the flexoelectric response in thin films as well as isolate and correct for piezoelectric contributions, which would otherwise dominate the flexoelectric measurement.