40 CFR 92.116 - Engine output measurement system calibrations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... calibration. (1) The engine flywheel torque and engine speed measurement transducers shall be calibrated with... performed with the dynamometer operating at a constant speed. The flywheel torque measurement device readout... practice requires that both devices have approximately equal useful ranges of torque measurement.) The...

40 CFR 92.116 - Engine output measurement system calibrations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... calibration. (1) The engine flywheel torque and engine speed measurement transducers shall be calibrated with... performed with the dynamometer operating at a constant speed. The flywheel torque measurement device readout... practice requires that both devices have approximately equal useful ranges of torque measurement.) The...

40 CFR 92.116 - Engine output measurement system calibrations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... calibration. (1) The engine flywheel torque and engine speed measurement transducers shall be calibrated with... performed with the dynamometer operating at a constant speed. The flywheel torque measurement device readout... practice requires that both devices have approximately equal useful ranges of torque measurement.) The...

40 CFR 92.116 - Engine output measurement system calibrations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... calibration. (1) The engine flywheel torque and engine speed measurement transducers shall be calibrated with... performed with the dynamometer operating at a constant speed. The flywheel torque measurement device readout... practice requires that both devices have approximately equal useful ranges of torque measurement.) The...

Development of DSRC device and communication system performance measures recommendations for DSRC OBE performance and security requirements.

DOT National Transportation Integrated Search

2016-05-22

This report presents recommendations for minimum DSRC device communication performance and security requirements to ensure effective operation of the DSRC system. The team identified recommended DSRC communications requirements aligned to use cases, ...

INNOVATIVE TECHNOLOGY VERIFICATION REPORT " ...

EPA Pesticide Factsheets

The EnSys Petro Test System developed by Strategic Diagnostics Inc. (SDI), was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in June 2000 at the Navy Base Ventura County site in Port Hueneme, California. The purpose of the demonstration was to collect reliable performance and cost data for the EnSys Petro Test System and six other field measurement devices for total petroleum hydrocarbons (TPH) in soil. In addition to assessing ease of device operation, the key objectives of the demonstration included determining the (1) method detection limit, (2) accuracy and precision, (3) effects of interferents and soil moisture content on TPH measurement, (4) sample throughput, and (5) TPH measurement costs for each device. The demonstration involved analysis of both performance evaluation samples and environmental samples collected in four areas contaminated with gasoline, diesel, or other petroleum products. The performance and cost results for a given field measurement device were compared to those for an off-site laboratory reference method,

INNOVATIVE TECHNOLOGY VERIFICATION REPORT " ...

EPA Pesticide Factsheets

The Synchronous Scanning Luminoscope (Luminoscope) developed by the Oak Ridge National Laboratory in collaboration with Environmental Systems Corporation (ESC) was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in June 2000 at the Navy Base Ventura County site in Port Hueneme, California. The purpose of the demonstration was to collect reliable performance and cost data for the Luminoscope and six other field measurement devices for total petroleum hydrocarbons (TPH) in soil. In addition to assessing ease of device operation, the key objectives of the demonstration included determining the (1) method detection limit, (2) accuracy and precision, (3) effects of interferents and soil moisture content on TPH measurement, (4) sample throughput, and (5) TPH measurement costs for each device. The demonstration involved analysis of both performance evaluation samples and environmental samples collected in five areas contaminated with gasoline, diesel, lubricating oil, or other petroleum products. The performance and cost results for a given field measurement device were compared to those for an off-site laboratory reference method,

Spectroradiometer Intercomparison and Impact on Characterizing Photovoltaic Device Performance: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habte, A.; Andreas, A.; Ottoson, L.

2014-11-01

Indoor and outdoor testing of photovoltaic (PV) device performance requires the use of solar simulators and natural solar radiation, respectively. This performance characterization requires accurate knowledge of spectral irradiance distribution that is incident on the devices. Spectroradiometers are used to measure the spectral distribution of solar simulators and solar radiation. On September 17, 2013, a global spectral irradiance intercomparison using spectroradiometers was organized by the Solar Radiation Research Laboratory (SRRL) at the National Renewable Energy Laboratory (NREL). This paper presents highlights of the results of this first intercomparison, which will help to decrease systematic inter-laboratory differences in the measurements ofmore » the outputs or efficiencies of PV devices and harmonize laboratory experimental procedures.« less

Technique for calibrating angular measurement devices when calibration standards are unavailable

NASA Technical Reports Server (NTRS)

Finley, Tom D.

1991-01-01

A calibration technique is proposed that will allow the calibration of certain angular measurement devices without requiring the use of absolute standard. The technique assumes that the device to be calibrated has deterministic bias errors. A comparison device must be available that meets the same requirements. The two devices are compared; one device is then rotated with respect to the other, and a second comparison is performed. If the data are reduced using the described technique, the individual errors of the two devices can be determined.

Multi-transmitter/multi-receiver high-speed measurements of soil resistivity and induced polarization - Hydrological application

NASA Astrophysics Data System (ADS)

Gance, Julien; Texier, Benoît; Leite, Orlando; Bernard, Jean; Truffert, Catherine; Lebert, François; Yamashita, Yoshihiro

2016-04-01

Electrical resistivity tomography (ERT) is an adapted tool for the monitoring of soil moisture variations in aquifers (Binley et al., 2015). Nevertheless, in some specific cases, like for highly permeable soils or fractured aquifers, the measurements from the device can be slower than the water flow through the entire investigated zone. Therefore, the monitoring of such phenomena cannot be performed with classical devices. In such cases, we require a high-speed measurement of soils resistivity. Since 20 years, the speed of acquisition of the resistivity meters has been improved by the development of multi-channel devices allowing to perform multi-electrode (> 4) measurements. The switching capabilities of the actual devices allow to measure over long profiles up to hundreds of electrodes only using one transmitter. Based on this multi-receiver technology and on previous work from Yamashita et al. (2013), authors have developed a 250 W multi-transmitter device for the high speed measurement of resistivity and induced polarization. Current is therefore injected simultaneously in the soil through six injection electrodes. The injected current is coded for each transmitter using Code Division Multiple Access (CDMA, Yamashita et al., 2014) so that the different voltages induced by each sources can be reconstructed from the total potential measurement signal at each receiver, allowing to save acquisition time. The first operational prototype features 3 transmitters and 6 receivers. Its performances are compared to a mono-transmitter device for different sequences of acquisition in 2D and 3D configurations both in theory and on real field data acquired on a shallow sedimentary aquifer in the Loire valley in France. This device is promising for the accurate monitoring of rapid water flows in heterogeneous aquifers.

Method and apparatus of a portable imaging-based measurement with self calibration

DOEpatents

Chang, Tzyy-Shuh [Ann Arbor, MI; Huang, Hsun-Hau [Ann Arbor, MI

2012-07-31

A portable imaging-based measurement device is developed to perform 2D projection based measurements on an object that is difficult or dangerous to access. This device is equipped with self calibration capability and built-in operating procedures to ensure proper imaging based measurement.

Vehicle brake testing system

DOEpatents

Stevens, Samuel S [Harriman, TN; Hodgson, Jeffrey W [Lenoir City, TN

2002-11-19

This invention relates to a force measuring system capable of measuring forces associated with vehicle braking and of evaluating braking performance. The disclosure concerns an invention which comprises a first row of linearly aligned plates, a force bearing surface extending beneath and beside the plates, vertically oriented links and horizontally oriented links connecting each plate to a force bearing surface, a force measuring device in each link, a transducer coupled to each force measuring device, and a computing device coupled to receive an output signal from the transducer indicative of measured force in each force measuring device. The present invention may be used for testing vehicle brake systems.

Performance study of the wearable one-lead wireless electrocardiographic monitoring system.

PubMed

Hong, Sungyoup; Yang, Yougmo; Kim, Seunghwan; Shin, Seungcheol; Lee, Inbum; Jang, Yongwon; Kim, Kiseong; Yi, Hwayeon

2009-03-01

This study attempts to compare and assess the performance of a wearable electrocardiogram (ECG) using a sensing fabric electrode and a Bluetooth network with a conventional ECG. A one-lead ECG examination was performed using Bioshirt and an iWorx 214 while walking or running at 3, 6, and 9 km per hour. A correlation coefficient of a heart rate variability (HRV) between these two devices was higher than 0.96 and power spectral density of HRV measured also showed an excellent agreement. Thus, both of these two ECG devices showed similar detection capability for R peaks. The measured values for wave duration and intervals of both devices concur with each other. The intensity of noise is controversial. The ECG device using a sensing fabric electrode and a wireless network showed an ECG signal detection and transmission capability similar to that of a conventional ECG device.

Validation of the OMRON M7 (HEM-780-E) blood pressure measuring device in a population requiring large cuff use according to the International Protocol of the European Society of Hypertension.

PubMed

El Feghali, Ramzi N; Topouchian, Jirar A; Pannier, Bruno M; El Assaad, Hiba A; Asmar, Roland G

2007-06-01

A high percentage of hypertensive patients present an arm circumference of over 32 cm; the use of a large cuff is therefore recommended. Validation studies are usually performed in the general population using a standard-size cuff. The aim of this study was to assess the accuracy of the Omron M7 device in a population with an arm circumference ranging from 32 to 42 cm. A validation study was performed according to the International Protocol of the European Society of Hypertension. This protocol is divided into two phases: the first phase is performed on 15 selected participants (45 pairs of blood-pressure measurements); if the device passes this phase, 18 supplementary participants are included (54 pairs of blood-pressure measurements), making a total number of 33 participants (99 pairs of blood-pressure measurements), on whom the analysis is performed. For each participant, four blood-pressure measurements were performed simultaneously by two trained observers, using mercury sphygmomanometers fitted with a Y tube; the measurements alternated with three by the test device. The difference between the blood-pressure value given by the device and that obtained by the two observers (mean of the two observations) was calculated for each measure. The 99 pairs of blood-pressure differences were classified into three categories (

Design fabrication and installation of a yaw measuring device

NASA Technical Reports Server (NTRS)

1979-01-01

The results of work performed in the development and testing of a yaw measuring device are summarized. A review of the yaw measurement method; and the techniques and hardware needed for its implementation are presented. A description and summary of the tests performed at the U.S. Bureau of Mines Bruceton facility are included. Conclusions are summarized and recommendations for a unit capable of operation in a mine environment are presented.

Error reduction by combining strapdown inertial measurement units in a baseball stitch

NASA Astrophysics Data System (ADS)

Tracy, Leah

A poor musical performance is rarely due to an inferior instrument. When a device is under performing, the temptation is to find a better device or a new technology to achieve performance objectives; however, another solution may be improving how existing technology is used through a better understanding of device characteristics, i.e., learning to play the instrument better. This thesis explores improving position and attitude estimates of inertial navigation systems (INS) through an understanding of inertial sensor errors, manipulating inertial measurement units (IMUs) to reduce that error and multisensor fusion of multiple IMUs to reduce error in a GPS denied environment.

Detection of gas leakage

DOEpatents

Thornberg, Steven M; Brown, Jason

2015-02-17

A method of detecting leaks and measuring volumes as well as a device, the Power-free Pump Module (PPM), provides a self-contained leak test and volume measurement apparatus that requires no external sources of electrical power during leak testing or volume measurement. The PPM is a portable, pneumatically-controlled instrument capable of generating a vacuum, calibrating volumes, and performing quantitative leak tests on a closed test system or device, all without the use of alternating current (AC) power. Capabilities include the ability is to provide a modest vacuum (less than 10 Torr) using a venturi pump, perform a pressure rise leak test, measure the gas's absolute pressure, and perform volume measurements. All operations are performed through a simple rotary control valve which controls pneumatically-operated manifold valves.

Food Application of Newly Developed Handy-type Glutamate Sensor.

PubMed

Mukai, Yuuka; Oikawa, Tsutomu

2016-01-01

Tests on physiological functions of umami have been actively conducted and a need recognized for a high-performance quantification device that is simple and cost-effective, and whose use is not limited to a particular location or user. To address this need, Ajinomoto Co. and Tanita Corp. have jointly been researching and developing a simple device for glutamate measurement. The device uses L-glutamate oxidase immobilized on a hydrogen peroxide electrode. L-glutamate in the sample is converted to α-ketoglutaric acid, which produces hydrogen peroxide. Subsequently, the electrical current from the electrochemical reaction of hydrogen peroxide is measured to determine the L-glutamate concentration. In order to evaluate its basic performance, we used this device to measure the concentration of L-glutamate standard solutions. In a concentration range of 0-1.0%, the difference from the theoretical value was minimal. The coefficient of variation (CV) value of 3 measurements was 4% or less. This shows that the device has a reasonable level of precision and accuracy. The device was also used in trial measurements of L-glutamate concentrations in food. There was a good correlation between the results obtained using the developed device and those obtained with an amino acid analyzer; the correlation coefficient was R=0.997 (n=24). In this review, we demonstrate the use of our device to measure the glutamate concentration in miso soup served daily at a home for elderly people, and other foods and ingredients.

The effects of interaction with the device described by procedural text on recall, true/false, and task performance.

PubMed

Diehl, V A; Mills, C B

1995-11-01

In two experiments, subjects interacted to different extents with relevant devices while reading two complex multistep procedural texts and were then tested with task performance time, true/false, and recall measures. While reading, subjects performed the task (read and do), saw the experimenter perform the task (read and see experimenter do), imagined doing the task (read and imagine), looked at the device while reading (read and see), or only read (read only). Van Dijk and Kintsch's (1983) text representation theory led to the prediction that exposure to the task device (in the read-and-do, read-and-see, and read-and-see-experimenter-do conditions) would lead to the development of a stronger situation model and therefore faster task performance, whereas the read-only and read-and-see conditions would lead to a better textbase, and therefore better performance on the true/false and recall tasks. Paivio's (1991) dual coding theory led to the opposite prediction for recall. The results supported the text representation theory with task performance and recall. The read-and-see condition produced consistently good performance on the true/false measure. Amount of text study time contributed to recall performance. These findings support the notion that information available while reading leads to differential development of representations in memory, which, in turn, causes differences in performance on various measures.

Trial of validation of two devices for self-measurement of blood pressure according to the European Society of Hypertension International Protocol: the Citizen CH-432B and the Citizen CH-656C.

PubMed

Cotte, Uwe V; Faltenbacher, Verena H; von Willich, Werner; Bogner, Johannes R

2008-02-01

Two devices for self-measurement of blood pressure, one at the upper arm (Citizen CH-432B) and one at the wrist (Citizen CH-656C), were evaluated according to the International Protocol of the European Society of Hypertension. The International Protocol is divided into two phases: the first phase is performed on 15 selected participants with five participants in three different blood pressure ranges. If the devices passed this phase, 18 additional participants selected on the basis of the same criteria as in phase 1 were included. Two skilled observers performed the following blood pressure measurements: five measurements were performed with the mercury standard alternating with four measurements with each of the test devices per participant. The first measurement result from each device instrument was not included in the analysis. The difference between the blood pressure value given by the devices and that obtained by the two observers (mean of the two observers) was calculated for each pair of measurements and classified into three categories (within 5, 10 and 15 mmHg). The results were compared to the pass criteria established by the European Society of Hypertension. Afterwards the number of measurement differences falling within 5 mmHg was determined for every person. At least 22 of the 33 participants should have two of their three comparisons within 5 mmHg and there should be a maximum of three participants without a measurement difference within the 5 mmHg range. Both tested devices passed the first phase of the validation process by exceeding the required number of comparisons falling within the 5, 10 and 15 mmHg error zones. Even the second phase confirmed the validation criteria with average differences between the device and the mercury sphygmomanometer of 0.7+/-4.4 and -3.6+/-4.0 mmHg for systolic blood pressure and diastolic blood pressure, respectively, for the Citizen CH-432B device and -0.7+/-6.0 and -1.2+/-4.5 mmHg for the Citizen CH-656C device. Phase 2 contains furthermore an individual analysis of the 33 participants, the requirements of which were also fulfilled by both devices. The Citizen CH-432B and the Citizen CH-656C devices pass the validation recommendations of the International Protocol. They can be recommended for clinical use.

Measurement of Retinal Sensitivity on Tablet Devices in Age-Related Macular Degeneration.

PubMed

Wu, Zhichao; Guymer, Robyn H; Jung, Chang J; Goh, Jonathan K; Ayton, Lauren N; Luu, Chi D; Lawson, David J; Turpin, Andrew; McKendrick, Allison M

2015-06-01

We compared measurements of central retinal sensitivity on a portable, low-cost tablet device to the established method of microperimetry in age-related macular degeneration (AMD). A customized test designed to measure central retinal sensitivity (within the central 1° radius) on a tablet device was developed using an open-source platform called PsyPad. A total of 30 participants with AMD were included in this study, and all participants performed a practice test on PsyPad, followed by four tests of one eye and one test of the other eye. Participants then underwent standardized microperimetry examinations in both eyes. The average test duration on PsyPad was 53.9 ± 7.5 seconds, and no significant learning effect was observed over the examinations performed ( P = 1.000). The coefficient of repeatability of central retinal sensitivity between the first two examinations on PsyPad was ±1.76 dB. The mean central retinal sensitivity was not significantly different between PsyPad (25.7 ± 0.4 dB) and microperimetry (26.1 ± 0.4 dB, P = 0.094), and the 95% limits of agreement between the two measures were between -4.12 and 4.92 dB. The measurements of central retinal sensitivity can be performed effectively using a tablet device, displaying reasonably good agreement with those obtained using the established method of microperimetry. These findings highlight the potential of tablet devices as low-cost and portable tools for developing and performing visual function measures that can be easily and widely implemented.

Electrical signature analysis to quantify human and animal performance on fitness and therapy equipment such as a treadmill

DOEpatents

Cox, Daryl F.; Hochanadel, Charles D.; Haynes, Howard D.

2010-05-18

The invention is a human and animal performance data acquisition, analysis, and diagnostic system for fitness and therapy devices having an interface box removably disposed on incoming power wiring to a fitness and therapy device, at least one current transducer removably disposed on said interface box for sensing current signals to said fitness and therapy device, and a means for analyzing, displaying, and reporting said current signals to determine human and animal performance on said device using measurable parameters.

Methodology in the measurement of complex human performance : two-dimensional compensatory tracking.

DOT National Transportation Integrated Search

1972-05-01

Nineteen subjects were tested on two successive days on a complex performance device designed to measure functions of relevance to aircrew performance; included were measures of monitoring, information processing, pattern discrimination, and group pr...

Molecular engineering to improve carrier lifetimes for organic photovoltaic devices with thick active layers

DOE PAGES

Oosterhout, Stefan D.; Braunecker, Wade A.; Owczarczyk, Zbyslaw R.; ...

2017-04-27

The morphology of the bulk heterojunction absorber layer in an organic photovoltaic (OPV) device has a profound effect on the electrical properties and efficiency of the device. Previous work has consistently demonstrated that the solubilizing side-chains of the donor material affect these properties and device performance in a non-trivial way. Here, using Time-Resolved Microwave Conductivity (TRMC), we show by direct measurements of carrier lifetimes that the choice of side chains can also make a substantial difference in photocarrier dynamics. We have previously demonstrated a correlation between peak photoconductance measured by TRMC and device efficiencies; here, we demonstrate that TRMC photocarriermore » dynamics have an important bearing on device performance in a case study of devices made from donor materials with linear vs. branched side-chains and with variable active layer thicknesses. We use Grazing-Incidence Wide Angle X-ray Scattering to elucidate the cause of the different carrier lifetimes as a function of different aggregation behavior in the polymers. Consequently, the results help establish TRMC as a technique for screening OPV donor materials whose devices maintain performance in thick active layers (>250 nm) designed to improve light harvesting, film reproducibility, and ease of processing.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bisio, Alessandro; D'Ariano, Giacomo Mauro; Perinotti, Paolo

We analyze quantum algorithms for cloning of a quantum measurement. Our aim is to mimic two uses of a device performing an unknown von Neumann measurement with a single use of the device. When the unknown device has to be used before the bipartite state to be measured is available we talk about 1{yields}2 learning of the measurement, otherwise the task is called 1{yields}2 cloning of a measurement. We perform the optimization for both learning and cloning for arbitrary dimension d of the Hilbert space. For 1{yields}2 cloning we also propose a simple quantum network that achieves the optimal fidelity.more » The optimal fidelity for 1{yields}2 learning just slightly outperforms the estimate and prepare strategy in which one first estimates the unknown measurement and depending on the result suitably prepares the duplicate.« less

Design of wearable health monitoring device

NASA Astrophysics Data System (ADS)

Devara, Kresna; Ramadhanty, Savira; Abuzairi, Tomy

2018-02-01

Wearable smart health monitoring devices have attracted considerable attention in both research community and industry. Some of the causes are the increasing healthcare costs, along with the growing technology. To address this demand, in this paper, design and evaluation of wearable health monitoring device integrated with smartphone were presented. This device was designed for patients in need of constant health monitoring. The performance of the proposed design has been tested by conducting measurement once in 2 minutes for 10 minutes to obtain heart rate and body temperature data. The comparation between data measured by the proposed device and that measured by the reference device yields only an average error of 1.45% for heart rate and 1.04% for body temperature.

Measuring Multiple Resistances Using Single-Point Excitation

NASA Technical Reports Server (NTRS)

Hall, Dan; Davies, Frank

2009-01-01

In a proposed method of determining the resistances of individual DC electrical devices connected in a series or parallel string, no attempt would be made to perform direct measurements on individual devices. Instead, (1) the devices would be instrumented by connecting reactive circuit components in parallel and/or in series with the devices, as appropriate; (2) a pulse or AC voltage excitation would be applied at a single point on the string; and (3) the transient or AC steady-state current response of the string would be measured at that point only. Each reactive component(s) associated with each device would be distinct in order to associate a unique time-dependent response with that device.

Outsourcing Security Services for Low Performance Portable Devices

NASA Astrophysics Data System (ADS)

Szentgyörgyi, Attila; Korn, András

The number of portable devices using wireless network technologies is on the rise. Some of these devices are incapable of, or at a disadvantage at using secure Internet services, because secure communication often requires comparatively high computing capacity. In this paper, we propose a solution which can be used to offer secure network services for low performance portable devices without severely degrading data transmission rates. We also show that using our approach these devices can utilize some secure network services which were so far unavailable to them due to a lack of software support. In order to back up our claims, we present performance measurement results obtained in a test network.

Performance of a new hand-held device for exhaled nitric oxide measurement in adults and children.

PubMed

Alving, K; Janson, C; Nordvall, L

2006-04-20

Exhaled nitric oxide (NO) measurement has been shown to be a valuable tool in the management of patients with asthma. Up to now, most measurements have been done with stationary, chemiluminescence-based NO analysers, which are not suitable for the primary health care setting. A hand-held NO analyser which simplifies the measurement would be of value both in specialized and primary health care. In this study, the performance of a new electrochemical hand-held device for exhaled NO measurements (NIOX MINO) was compared with a standard stationary chemiluminescence unit (NIOX). A total of 71 subjects (6-60 years; 36 males), both healthy controls and atopic patients with and without asthma were included. The mean of three approved exhalations (50 ml/s) in each device, and the first approved measurement in the hand-held device, were compared with regard to NO readings (Bland-Altman plots), measurement feasibility (success rate with 6 attempts) and repeatability (intrasubject SD). Success rate was high (> or = 84%) in both devices for both adults and children. The subjects represented a FENO range of 8-147 parts per billion (ppb). When comparing the mean of three measurements (n = 61), the median of the intrasubject difference in exhaled NO for the two devices was -1.2 ppb; thus generally the hand-held device gave slightly higher readings. The Bland-Altman plot shows that the 95% limits of agreement were -9.8 and 8.0 ppb. The intrasubject median difference between the NIOX and the first approved measurement in the NIOX MINO was -2.0 ppb, and limits of agreement were -13.2 and 10.2 ppb. The median repeatability for NIOX and NIOX MINO were 1.1 and 1.2 ppb, respectively. The hand-held device (NIOX MINO) and the stationary system (NIOX) are in clinically acceptable agreement both when the mean of three measurements and the first approved measurement (NIOX MINO) is used. The hand-held device shows good repeatability, and it can be used successfully on adults and most children. The new hand-held device will enable the introduction of exhaled NO measurements into the primary health care.

Development of a MEMS device for acoustic emission testing

NASA Astrophysics Data System (ADS)

Ozevin, Didem; Pessiki, Stephen P.; Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2003-08-01

Acoustic emission testing is an important technology for evaluating structural materials, and especially for detecting damage in structural members. Significant new capabilities may be gained by developing MEMS transducers for acoustic emission testing, including permanent bonding or embedment for superior coupling, greater density of transducer placement, and a bundle of transducers on each device tuned to different frequencies. Additional advantages include capabilities for maintenance of signal histories and coordination between multiple transducers. We designed a MEMS device for acoustic emission testing that features two different mechanical types, a hexagonal plate design and a spring-mass design, with multiple detectors of each type at ten different frequencies in the range of 100 kHz to 1 MHz. The devices were fabricated in the multi-user polysilicon surface micromachining (MUMPs) process and we have conducted electrical characterization experiments and initial experiments on acoustic emission detection. We first report on C(V) measurements and perform a comparison between predicted (design) and measured response. We next report on admittance measurements conducted at pressures varying from vacuum to atmospheric, identifying the resonant frequencies and again providing a comparison with predicted performance. We then describe initial calibration experiments that compare the performance of the detectors to other acoustic emission transducers, and we discuss the overall performance of the device as a sensor suite, as contrasted to the single-channel performance of most commercial transducers.

Assessment of laboratory and daily energy expenditure estimates from consumer multi-sensor physical activity monitors.

PubMed

Chowdhury, Enhad A; Western, Max J; Nightingale, Thomas E; Peacock, Oliver J; Thompson, Dylan

2017-01-01

Wearable physical activity monitors are growing in popularity and provide the opportunity for large numbers of the public to self-monitor physical activity behaviours. The latest generation of these devices feature multiple sensors, ostensibly similar or even superior to advanced research instruments. However, little is known about the accuracy of their energy expenditure estimates. Here, we assessed their performance against criterion measurements in both controlled laboratory conditions (simulated activities of daily living and structured exercise) and over a 24 hour period in free-living conditions. Thirty men (n = 15) and women (n = 15) wore three multi-sensor consumer monitors (Microsoft Band, Apple Watch and Fitbit Charge HR), an accelerometry-only device as a comparison (Jawbone UP24) and validated research-grade multi-sensor devices (BodyMedia Core and individually calibrated Actiheart™). During discrete laboratory activities when compared against indirect calorimetry, the Apple Watch performed similarly to criterion measures. The Fitbit Charge HR was less consistent at measurement of discrete activities, but produced similar free-living estimates to the Apple Watch. Both these devices underestimated free-living energy expenditure (-394 kcal/d and -405 kcal/d, respectively; P<0.01). The multi-sensor Microsoft Band and accelerometry-only Jawbone UP24 devices underestimated most laboratory activities and substantially underestimated free-living expenditure (-1128 kcal/d and -998 kcal/d, respectively; P<0.01). None of the consumer devices were deemed equivalent to the reference method for daily energy expenditure. For all devices, there was a tendency for negative bias with greater daily energy expenditure. No consumer monitors performed as well as the research-grade devices although in some (but not all) cases, estimates were close to criterion measurements. Thus, whilst industry-led innovation has improved the accuracy of consumer monitors, these devices are not yet equivalent to the best research-grade devices or indeed equivalent to each other. We propose independent quality standards and/or accuracy ratings for consumer devices are required.

Assessment of laboratory and daily energy expenditure estimates from consumer multi-sensor physical activity monitors

PubMed Central

Chowdhury, Enhad A.; Western, Max J.; Nightingale, Thomas E.; Peacock, Oliver J.; Thompson, Dylan

2017-01-01

Wearable physical activity monitors are growing in popularity and provide the opportunity for large numbers of the public to self-monitor physical activity behaviours. The latest generation of these devices feature multiple sensors, ostensibly similar or even superior to advanced research instruments. However, little is known about the accuracy of their energy expenditure estimates. Here, we assessed their performance against criterion measurements in both controlled laboratory conditions (simulated activities of daily living and structured exercise) and over a 24 hour period in free-living conditions. Thirty men (n = 15) and women (n = 15) wore three multi-sensor consumer monitors (Microsoft Band, Apple Watch and Fitbit Charge HR), an accelerometry-only device as a comparison (Jawbone UP24) and validated research-grade multi-sensor devices (BodyMedia Core and individually calibrated Actiheart™). During discrete laboratory activities when compared against indirect calorimetry, the Apple Watch performed similarly to criterion measures. The Fitbit Charge HR was less consistent at measurement of discrete activities, but produced similar free-living estimates to the Apple Watch. Both these devices underestimated free-living energy expenditure (-394 kcal/d and -405 kcal/d, respectively; P<0.01). The multi-sensor Microsoft Band and accelerometry-only Jawbone UP24 devices underestimated most laboratory activities and substantially underestimated free-living expenditure (-1128 kcal/d and -998 kcal/d, respectively; P<0.01). None of the consumer devices were deemed equivalent to the reference method for daily energy expenditure. For all devices, there was a tendency for negative bias with greater daily energy expenditure. No consumer monitors performed as well as the research-grade devices although in some (but not all) cases, estimates were close to criterion measurements. Thus, whilst industry-led innovation has improved the accuracy of consumer monitors, these devices are not yet equivalent to the best research-grade devices or indeed equivalent to each other. We propose independent quality standards and/or accuracy ratings for consumer devices are required. PMID:28234979

FIELD DEMONSTRATION AND QUALITY ASSURANCE ...

EPA Pesticide Factsheets

The Demonstration of innovative field devices for the measurement of mercury in soil and sediment is being conducted under the EPA's SITE Program in February 2003 at the United States Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee and the Tennessee Department of Environment and Conservation's Department of Energy Oversight facility in Oak Ridge, Tennessee. The primary purpose of the Demonstration is to evaluate innovative field devices for the measurement of mercury in soil and sediment based on their performance and cost as compared to a conventional, off-site laboratory analytical method. The five field measurement devices listed below will be demonstrated: .Metorex's X-M ET 2000 Metal Master Analyzer, X-Ray Fluorescence Analyzer .Milestone Inc.'s Direct Mercury Analyzer (DMA-80), Thermal Decomposition Instrument.NITON's XL-700 Series Multi-Element Analyzer, X-Ray Fluorescence Analyzer .Ohio Lumex's RA-915+ Portable Mercury Analyzer, Atomic Absorption Spectrometer, Thermal Decompostion Attachment RP 91C .MTI, Inc.'s PDV 5000 Hand Held Instrument, Anodic Stripping Voltamm eter<1). This Demonstration Plan describes the procedures that will be used to verify the performance and cost of each field measurement device. The plan incorporates the quality assurance and quality control elements needed to generate data of sufficient quality to document each device's performance and cost. A separate Innovative Technology Verifica

Probing of barrier induced deviations in current-voltage characteristics of polymer devices by impedance spectroscopy

NASA Astrophysics Data System (ADS)

Khan, Motiur Rahman; Rao, K. S. R. Koteswara; Menon, R.

2017-05-01

Temperature dependent current-voltage measurements have been performed on poly(3-methylthiophene) based devices in metal/polymer/metal geometry in temperature range 90-300 K. Space charge limited current (SCLC) controlled by exponentially distributed traps is observed at all the measured temperatures at intermediate voltage range. At higher voltages, trap-free SCLC is observed at 90 K only while slope less than 2 is observed at higher temperatures which is quiet unusual in polymer devices. Impedance measurements were performed at different bias voltages. The unusual behavior observed in current-voltage characteristics is explained by Cole-Cole plot which gives the signature of interface dipole on electrode/polymer interface. Two relaxation mechanisms are obtained from the real part of impedance vs frequency spectra which confirms the interface related phenomena in the device

Smart ECG Monitoring Patch with Built-in R-Peak Detection for Long-Term HRV Analysis.

PubMed

Lee, W K; Yoon, H; Park, K S

2016-07-01

Since heart rate variability (HRV) analysis is widely used to evaluate the physiological status of the human body, devices specifically designed for such applications are needed. To this end, we developed a smart electrocardiography (ECG) patch. The smart patch measures ECG using three electrodes integrated into the patch, filters the measured signals to minimize noise, performs analog-to-digital conversion, and detects R-peaks. The measured raw ECG data and the interval between the detected R-peaks can be recorded to enable long-term HRV analysis. Experiments were performed to evaluate the performance of the built-in R-wave detection, robustness of the device under motion, and applicability to the evaluation of mental stress. The R-peak detection results obtained with the device exhibited a sensitivity of 99.29%, a positive predictive value of 100.00%, and an error of 0.71%. The device also exhibited less motional noise than conventional ECG recording, being stable up to a walking speed of 5 km/h. When applied to mental stress analysis, the device evaluated the variation in HRV parameters in the same way as a normal ECG, with very little difference. This device can help users better understand their state of health and provide physicians with more reliable data for objective diagnosis.

Correlation of Handheld Infrared Skin Thermometer and Infrared Videothermography Device for Measurement of Corneal Temperature.

PubMed

Oztas, Zafer; Barut Selver, Ozlem; Akkin, Cezmi; Canturk, Ecem; Afrashi, Filiz

2016-05-01

In our study, we aimed to investigate the correlation of handheld infrared skin thermometer and videothermography device for the measurement of corneal temperature. Forty healthy individuals (80 eyes) were enrolled to the study. Participants underwent a detailed ophthalmologic examination and medical history review for excluding any ocular and systemic diseases. The measurements of the central corneal temperature were performed in a room having constant temperature, humidity, and brightness levels. To avoid any variability, all the temperature measurements were performed in the same examination room by a single examiner. The temperature was measured with a handheld infrared skin thermometer (MEDISANA, FTN) from the corneal surface. The same instrument was also used to measure the subjects' body temperature. Moreover, the subjects underwent the corneal temperature measurement by a noncontact videothermography device (Optris PI 450; Optris GmbH). The male to female ratio was 19:21 among the subjects. The mean age was 25.1±4.7 years. The mean body temperature was 36.93±0.33°C. The mean corneal temperatures measured by the handheld infrared skin thermometer and the ocular videothermography device were 36.94±0.28°C and 35.61±0.61°C, respectively (P<0.01). The mean temperature difference was 1.34±0.57°C, with a 95% confidence interval. There was a moderate correlation between the corneal temperatures measured by the 2 devices in the right, the left eyes, and both eyes, respectively (P=0.450, 0.539, 0.490). Handheld infrared skin thermometers can be used for the evaluation of the corneal temperature. These devices may provide a simple, practical, and cheaper way to detect the corneal temperature, and the widely performed corneal temperature measurements may afford us to understand the temperature variability in numerous ocular conditions in a better way.

Integrated spectral photocurrent density and reproducibility analyses of excitonic ZnO/NiO heterojunction.

PubMed

Patel, Malkeshkumar; Kim, Joondong

2017-12-01

In this data article, the excitonic ZnO/NiO heterojunction device (Patel et al., 2017) [1] was measured for the integrated photocurrent density and reproducibility. Photograph of the prepared devices of ZnO/NiO on the FTO/glass is presented. Integrated photocurrent density as a function of photon energy from the sunlight is presented. Quantum efficiency measurement system (McScienceK3100, Korea) compliance with International Measurement System was employed to measure ZnO/NIO devices. These data are shown for the 300-440 nm of segment of the sunlight (AM1.5G, http://rredc.nrel.gov/solar/spectra/am1.5/). Reproducibility measure of ZnO/NiO device was presented for nine devices with the estimated device performance parameters including the open circuit voltage, short circuit current density, fill factor and power conversion efficiency.

Design, fabrication, and delivery of a charge injection device as a stellar tracking device

NASA Technical Reports Server (NTRS)

Burke, H. K.; Michon, G. J.; Tomlinson, H. W.; Vogelsong, T. L.; Grafinger, A.; Wilson, R.

1979-01-01

Six 128 x 128 CID imagers fabricated on bulk silicon and with thin polysilicon upper-level electrodes were tested in a star tracking mode. Noise and spectral response were measured as a function of temperature over the range of +25 C to -40 C. Noise at 0 C and below was less than 40 rms carriers/pixel for all devices at an effective noise bandwidth of 150 Hz. Quantum yield for all devices averaged 40% from 0.4 to 1.0 microns with no measurable temperature dependence. Extrapolating from these performance parameters to those of a large (400 x 400) array and accounting for design and processing improvements, indicates that the larger array would show a further improvement in noise performance -- on the order of 25 carriers. A preliminary evaluation of the projected performance of the 400 x 400 array and a representative set of star sensor requirements indicates that the CID has excellent potential as a stellar tracking device.

Results of the first semi-annual qualification testing of devices to measure breath alcohol

DOT National Transportation Integrated Search

1975-01-01

Eight evidential breath testers were performance tested according to the Standard for Devices to Measure Breath Alcohol Federal Register, Vol 38, No. 212, November 5, 1973. In addition, a prototype breath tester not commercially available was tested....

Performance analysis of resistive switching devices based on BaTiO3 thin films

NASA Astrophysics Data System (ADS)

Samardzic, Natasa; Kojic, Tijana; Vukmirovic, Jelena; Tripkovic, Djordjije; Bajac, Branimir; Srdic, Vladimir; Stojanovic, Goran

2016-03-01

Resitive switching devices, memristors, have recenty attracted much attention due to promising performances and potential applications in the field of logic and memory devices. Here, we present thin film BaTiO3 based memristor fabricated using ink-jet printing technique. Active material is a single layer barium titanate film with thickness of ̴100 nm, sandwitched between metal electodes. Printing parameters were optimized aiming to achieve stable drop flow and uniform printed layer. Current-voltage characteristics show typical memristive behavior with pinched hysteresis loop crossed at the origin, with marked differences between High Resistive State (HRS) and Low Resistive State (LRS). Obtained resistive states are stable during numerous switching processes. The device also shows unipolar switching effect for negative voltage impulses. Variable voltage impulse amplitudes leads to the shifting of the energy levels of electode contacts resulting in changing of the overall current through the device. Structural charcterization have been performed using XRD analysis and SEM micrography. High-temperature current-voltage measurements combined with transport parameter analysis using Hall efect measurement system (HMS 3000) and Impedance Analyzer AC measurements allows deeper insigth into conduction mechanism of ferroelectric memristors.

Hafnia-based resistive switching devices for non-volatile memory applications and effects of gamma irradiation on device performance

NASA Astrophysics Data System (ADS)

Arun, N.; Kumar, K. Vinod; Pathak, A. P.; Avasthi, D. K.; Nageswara Rao, S. V. S.

2018-04-01

Non-volatile memory (NVM) devices were fabricated as a Metal- Insulator-Metal (MIM) structures by sandwiching Hafnium dioxide (HfO2) thin film in between two metal electrodes. The top and bottom metal electrodes were deposited by using the thermal evaporation, and the oxide layer was deposited by using the RF magnetron sputtering technique. The Resistive Random Access Memory (RRAM) device structures such as Ag/HfO2/Au/Si were fabricated and I-V characteristics for the pristine and gamma-irradiated devices with a dose 24 kGy were measured. Further we have studied the thermal annealing effects, in the range of 100°-400°C in a tubular furnace for the HfO2/Au/Si samples. The X-ray diffraction (XRD), Rutherford Backscattering Spectrometry (RBS), field emission-scanning electron microscopy (FESEM) analysis measurements were performed to determine the thickness, crystallinity and stoichiometry of these films. The electrical characteristics such as resistive switching, endurance, retention time and switching speed were measured by a semiconductor device analyser. The effects of gamma irradiation on the switching properties of these RRAM devices have been studied.

Electrical signal analysis to assess the physical condition of a human or animal

DOEpatents

Cox, Daryl F.; Hochanadel, Charles D.; Haynes, Howard D.

2010-06-15

The invention is a human and animal performance data acquisition, analysis, and diagnostic system for fitness and therapy devices having an interface box removably disposed on incoming power wiring to a fitness and therapy device, at least one current transducer removably disposed on said interface box for sensing current signals to said fitness and therapy device, and a means for analyzing, displaying, and reporting said current signals to determine human and animal performance on said device using measurable parameters.

Mesure des champs de radiation dans le detecteur ATLAS et sa caverne avec les detecteurs au silicium a pixels ATLAS-MPX

NASA Astrophysics Data System (ADS)

Bouchami, Jihene

The LHC proton-proton collisions create a hard radiation environment in the ATLAS detector. In order to quantify the effects of this environment on the detector performance and human safety, several Monte Carlo simulations have been performed. However, direct measurement is indispensable to monitor radiation levels in ATLAS and also to verify the simulation predictions. For this purpose, sixteen ATLAS-MPX devices have been installed at various positions in the ATLAS experimental and technical areas. They are composed of a pixelated silicon detector called MPX whose active surface is partially covered with converter layers for the detection of thermal, slow and fast neutrons. The ATLAS-MPX devices perform real-time measurement of radiation fields by recording the detected particle tracks as raster images. The analysis of the acquired images allows the identification of the detected particle types by the shapes of their tracks. For this aim, a pattern recognition software called MAFalda has been conceived. Since the tracks of strongly ionizing particles are influenced by charge sharing between adjacent pixels, a semi-empirical model describing this effect has been developed. Using this model, the energy of strongly ionizing particles can be estimated from the size of their tracks. The converter layers covering each ATLAS-MPX device form six different regions. The efficiency of each region to detect thermal, slow and fast neutrons has been determined by calibration measurements with known sources. The study of the ATLAS-MPX devices response to the radiation produced by proton-proton collisions at a center of mass energy of 7 TeV has demonstrated that the number of recorded tracks is proportional to the LHC luminosity. This result allows the ATLAS-MPX devices to be employed as luminosity monitors. To perform an absolute luminosity measurement and calibration with these devices, the van der Meer method based on the LHC beam parameters has been proposed. Since the ATLAS-MPX devices response and the luminosity are correlated, the results of measuring radiation levels are expressed in terms of particle fluences per unit integrated luminosity. A significant deviation has been obtained when comparing these fluences with those predicted by GCALOR, which is one of the ATLAS detector simulations. In addition, radiation measurements performed at the end of proton-proton collisions have demonstrated that the decay of radionuclides produced during collisions can be observed with the ATLAS-MPX devices. The residual activation of ATLAS components can be measured with these devices by means of ambient dose equivalent calibration. Keywords: pattern recognition, charge sharing effect, neutron detection efficiency, luminosity, van der Meer method, particle fluences, GCALOR simulation, residual activation, ambient dose equivalent.

Designing Security-Hardened Microkernels For Field Devices

NASA Astrophysics Data System (ADS)

Hieb, Jeffrey; Graham, James

Distributed control systems (DCSs) play an essential role in the operation of critical infrastructures. Perimeter field devices are important DCS components that measure physical process parameters and perform control actions. Modern field devices are vulnerable to cyber attacks due to their increased adoption of commodity technologies and that fact that control networks are no longer isolated. This paper describes an approach for creating security-hardened field devices using operating system microkernels that isolate vital field device operations from untrusted network-accessible applications. The approach, which is influenced by the MILS and Nizza architectures, is implemented in a prototype field device. Whereas, previous microkernel-based implementations have been plagued by poor inter-process communication (IPC) performance, the prototype exhibits an average IPC overhead for protected device calls of 64.59 μs. The overall performance of field devices is influenced by several factors; nevertheless, the observed IPC overhead is low enough to encourage the continued development of the prototype.

Evaluation of an innovative sensor for measuring global and diffuse irradiance, and sunshine duration

NASA Astrophysics Data System (ADS)

Muneer, Tariq; Zhang, Xiaodong; Wood, John

2002-03-01

Delta-T Device Limited of Cambridge, UK have developed an integrated device which enables simultaneous measurement of horizontal global and diffuse irradiance as well as sunshine status at any given instance in time. To evaluate the performance of this new device, horizontal global and diffuse irradiance data were simultaneously collected from Delta-T device and Napier University's CIE First Class daylight monitoring station. To enable a cross check a Kipp & Zonen CM11 global irradiance sensor has also been installed in Currie, south-west Edinburgh. Sunshine duration data have been recorded at the Royal Botanical Garden, Edinburgh using their Campbell-Stokes recorder. Hourly data sets were analysed and plotted within the Microsoft Excel environment. Using the common statistical measures, Root Mean Square Difference (RMSD) and Mean Bias Difference (MBD) the accuracy of measurements of Delta-T sensor's horizontal global and diffuse irradiance, and sunshine duration were investigated. The results show a good performance on the part of Delta-T device for the measurement of global and diffuse irradiance. The sunshine measurements were found to have a lack of consistency and accuracy. It is argued herein that the distance between the respective sensors and the poor accuracy of Campbell-Stokes recorder may be contributing factors to this phenomenon.

An experimental study of an airfoil with a bio-inspired leading edge device at high angles of attack

NASA Astrophysics Data System (ADS)

Mandadzhiev, Boris A.; Lynch, Michael K.; Chamorro, Leonardo P.; Wissa, Aimy A.

2017-09-01

Robust and predictable aerodynamic performance of unmanned aerial vehicles at the limits of their design envelope is critical for safety and mission adaptability. Deployable aerodynamic surfaces from the wing leading or trailing edges are often used to extend the aerodynamic envelope (e.g. slats and flaps). Birds have also evolved feathers at the leading edge (LE) of their wings, known as the alula, which enables them to perform high angles of attack maneuvers. In this study, a series of wind tunnel experiments are performed to quantify the effect of various deployment parameters of an alula-like LE device on the aerodynamic performance of a cambered airfoil (S1223) at stall and post stall conditions. The alula relative angle of attack, measured from the mean chord of the airfoil, is varied to modulate tip-vortex strength, while the alula deflection angle is varied to modulate the distance between the tip vortex and the wing surface. Integrated lift force measurements were collected at various alula-inspired device configurations. The effect of the alula-inspired device on the boundary layer velocity profile and turbulence intensity were investigated through hot-wire anemometer measurements. Results show that as alula deflection angle increases, the lift coefficient also increase especially at lower alula relative angles of attack. Moreover, at post stall wing angles of attack, the wake velocity deficit is reduced in the presence of alula device, confirming the mitigation of the wing adverse pressure gradient. The results are in strong agreement with measurements taken on bird wings showing delayed flow reversal and extended range of operational angles of attack. An engineered alula-inspired device has the potential to improve mission adaptability in small unmanned air vehicles during low Reynolds number flight.

Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conover, David R.; Crawford, Alasdair J.; Fuller, Jason

This Protocol provides a set of “best practices” for characterizing energy storage systems (ESSs) and measuring and reporting their performance. It serves as a basis for assessing how an ESS will perform with respect to key performance attributes relevant to different applications. It is intended to provide a valid and accurate basis for the comparison of different ESSs. By achieving the stated purpose, the Protocol will enable more informed decision-making in the selection of ESSs for various stationary applications. The Protocol identifies general information and technical specifications relevant in describing an ESS and also defines a set of test, measurement,more » and evaluation criteria with which to express the performance of ESSs that are intended for energy-intensive and/or power-intensive stationary applications. An ESS includes a storage device, battery management system, and any power conversion systems installed with the storage device. The Protocol is agnostic with respect to the storage technology and the size and rating of the ESS. The Protocol does not apply to single-use storage devices and storage devices that are not coupled with power conversion systems, nor does it address safety, security, or operations and maintenance of ESSs, or provide any pass/fail criteria.« less

Improvement of the accuracy of noise measurements by the two-amplifier correlation method.

PubMed

Pellegrini, B; Basso, G; Fiori, G; Macucci, M; Maione, I A; Marconcini, P

2013-10-01

We present a novel method for device noise measurement, based on a two-channel cross-correlation technique and a direct "in situ" measurement of the transimpedance of the device under test (DUT), which allows improved accuracy with respect to what is available in the literature, in particular when the DUT is a nonlinear device. Detailed analytical expressions for the total residual noise are derived, and an experimental investigation of the increased accuracy provided by the method is performed.

Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.

PubMed

Long, Guankui; Wu, Bo; Yang, Xuan; Kan, Bin; Zhou, Ye-Cheng; Chen, Li-Chuan; Wan, Xiangjian; Zhang, Hao-Li; Sum, Tze Chien; Chen, Yongsheng

2015-09-30

Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.

Backside-illuminated 6.6-μm pixel video-rate CCDs for scientific imaging applications

NASA Astrophysics Data System (ADS)

Tower, John R.; Levine, Peter A.; Hsueh, Fu-Lung; Patel, Vipulkumar; Swain, Pradyumna K.; Meray, Grazyna M.; Andrews, James T.; Dawson, Robin M.; Sudol, Thomas M.; Andreas, Robert

2000-05-01

A family of backside illuminated CCD imagers with 6.6 micrometers pixels has been developed. The imagers feature full 12 bit (> 4,000:1) dynamic range with measured noise floor of < 10 e RMS at 5 MHz clock rates, and measured full well capacity of > 50,000 e. The modulation transfer function performance is excellent, with measured MTF at Nyquist of 46% for 500 nm illumination. Three device types have been developed. The first device is a 1 K X 1 K full frame device with a single output port, which can be run as a 1 K X 512 frame transfer device. The second device is a 512 X 512 frame transfer device with a single output port. The third device is a 512 X 512 split frame transfer device with four output ports. All feature the high quantum efficiency afforded by backside illumination.

Influence of the ambient temperature on the cooling efficiency of the high performance cooling device with thermosiphon effect

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan

2018-06-01

This work deal with experimental measurement and calculation cooling efficiency of the cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description, working principle and construction of cooling device. The main factor affected the dissipation of high heat flux from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. Experimental part describe the measuring method cooling efficiency of the cooling device depending on ambient temperature in range -20 to 40°C and at heat load of electronic components 750 W. Measured results are compared with results calculation based on physical phenomena of boiling, condensation and natural convection heat transfer.

A catalogue of devices applicable to the measurement of boundary layers and wakes on flight vehicles

NASA Technical Reports Server (NTRS)

Miley, S. J.

1972-01-01

A literature search was conducted to assemble a catalog of devices and techniques which have possible application to boundary layer and wake measurements on flight vehicles. The indices used in the search were NACA, NASA STAR, IAA, USGRDR and Applied Science and Technology Index. The period covered was 1950 through 1970. The devices contained in the catalog were restricted to those that provided essentially direct measurement of velocities, pressures and shear stresses. Pertinent material was included in the catalog if it contained either an adequate description of a device and associated performance data or a presentation of applicable information on a particular measurement theory and/or technique. When available, illustrations showing the configuration of the device and test condition data were also included.

The Icare HOME (TA022) Study: Performance of an Intraocular Pressure Measuring Device for Self-Tonometry by Glaucoma Patients.

PubMed

Mudie, Lucy I; LaBarre, Sophie; Varadaraj, Varshini; Karakus, Sezen; Onnela, Jouni; Munoz, Beatriz; Friedman, David S

2016-08-01

To evaluate the Icare HOME (TA022) device (Icare Oy, Vanda, Finland) for use by glaucoma patients for self-tonometry. Prospective performance evaluation of a medical device. One hundred eighty-nine participants with glaucoma or suspected glaucoma were recruited from the Wilmer Eye Institute, Baltimore, Maryland, between July 2014 and April 2015. Participants had standardized training and had to be able use the Icare HOME device independently. Subjects also had to be able to obtain the first intraocular pressure (IOP) measurement within 5 mmHg of Goldmann applanation tonometry (GAT). Those certified obtained 3 IOP measures using the HOME device, and these were compared with Icare TA01i and GAT IOP measurements. The agreement between Icare HOME and reference tonometers was used to assess precision. The intraclass correlation coefficient was used to assess within-patient reliability for the HOME device. Eighteen of 189 recruited patients were ineligible to take part in the study. Forty-four of 171 patients (25.7%) started but failed to complete the study: 7 stopped because of time concerns, 10 of 171 patients (6%) stopped because of difficulty using the device during certification, and 27 of 171 patients (16%) failed to be certified based on IOP. The HOME and GAT measurements agreed within 5 mmHg in 116 of 127 participants (91.3%); 2 participants (1.6%) had a difference of more than 7 mmHg. The mean difference between the Icare HOME and GAT measurements was -0.33 mmHg (standard deviation, 3.11 mmHg). The overall intraclass correlation coefficient for the HOME device was 0.92 (95% confidence interval, 0.89-0.95). Not all participants could learn how to use the Icare HOME device, but for those who could, most were able to obtain measurements similar to those obtained by GAT. The Icare HOME device is safe and reliable for self-tonometry, but nearly 1 in 6 individuals may fail to certify in use of the device based on large differences in IOP when comparing GAT with the Icare HOME measurements. The device has the potential to address an unmet need by providing more frequent IOP measurements in a patient's day to day life. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

A device to improve the Schleger and Turner method for sweating rate measurements

NASA Astrophysics Data System (ADS)

Pereira, Alfredo Manuel Franco; Alves, Alexandre; Infante, Paulo; Titto, Evaldo A. L.; Baccari, Flávio; Almeida, J. A. Afonso

2010-01-01

The objective of this study was to test a device developed to improve the functionality, accuracy and precision of the original technique for sweating rate measurements proposed by Schleger and Turner [Schleger AV, Turner HG (1965) Aust J Agric Res 16:92-106]. A device was built for this purpose and tested against the original Schleger and Turner technique. Testing was performed by measuring sweating rates in an experiment involving six Mertolenga heifers subjected to four different thermal levels in a climatic chamber. The device exhibited no functional problems and the results obtained with its use were more consistent than with the Schleger and Turner technique. There was no difference in the reproducibility of the two techniques (same accuracy), but measurements performed with the new device had lower repeatability, corresponding to lower variability and, consequently, to higher precision. When utilizing this device, there is no need for physical contact between the operator and the animal to maintain the filter paper discs in position. This has important advantages: the animals stay quieter, and several animals can be evaluated simultaneously. This is a major advantage because it allows more measurements to be taken in a given period of time, increasing the precision of the observations and diminishing the error associated with temporal hiatus (e.g., the solar angle during field studies). The new device has higher functional versatility when taking measurements in large-scale studies (many animals) under field conditions. The results obtained in this study suggest that the technique using the device presented here could represent an advantageous alternative to the original technique described by Schleger and Turner.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowder, Stephen V.

This document outlines a statistical framework for establishing a shelf-life program for components whose performance is measured by the value of a continuous variable such as voltage or function time. The approach applies to both single measurement devices and repeated measurement devices, although additional process control charts may be useful in the case of repeated measurements. The approach is to choose a sample size that protects the margin associated with a particular variable over the life of the component. Deviations from expected performance of the measured variable are detected prior to the complete loss of margin. This ensures the reliabilitymore » of the component over its lifetime.« less

Performance evaluation of photoacoustic oximetry imaging systems using a dynamic blood flow phantom with tunable oxygen saturation

NASA Astrophysics Data System (ADS)

Vogt, William C.; Zhou, Xuewen; Andriani, Rudy; Wear, Keith A.; Garra, Brian S.; Pfefer, Joshua

2018-02-01

Photoacoustic Imaging (PAI) is an emerging technology with strong potential for broad clinical applications from breast cancer detection to cerebral monitoring due to its ability to compute maps of blood oxygen saturation (SO2) distribution in deep tissues using multispectral imaging. However, no well-validated consensus test methods currently exist for evaluating oximetry-specific performance characteristics of PAI devices. We have developed a phantombased flow system capable of rapid SO2 adjustment to serve as a test bed for elucidation of factors impacting SO2 measurement and quantitative characterization of device performance. The flow system is comprised of a peristaltic pump, membrane oxygenator, oxygen and nitrogen gas, and in-line oxygen, pH, and temperature sensors that enable real-time estimation of SO2 reference values. Bovine blood was delivered through breast-relevant tissue phantoms containing vessel-mimicking fluid channels, which were imaged using a custom multispectral PAI system. Blood was periodically drawn for SO2 measurement in a clinical-grade CO-oximeter. We used this flow phantom system to evaluate the impact of device parameters (e.g.,wavelength-dependent fluence corrections) and tissue parameters (e.g. fluid channel depth, blood SO2, spectral coloring artifacts) on oximetry measurement accuracy. Results elucidated key challenges in PAI oximetry and device design trade-offs, which subsequently allowed for optimization of system performance. This approach provides a robust benchtop test platform that can support PAI oximetry device optimization, performance validation, and clinical translation, and may inform future development of consensus test methods for performance assessment of photoacoustic oximetry imaging systems.

Quantification of error associated with stormwater and wastewater flow measurement devices

EPA Science Inventory

A novel flow testbed has been designed to evaluate the performance of flumes as flow measurement devices. The newly constructed testbed produces both steady and unsteady flows ranging from 10 to 1500 gpm. Two types of flumes (Parshall and trapezoidal) are evaluated under differen...

Optimal MEMS device for mobility and zeta potential measurements using DC electrophoresis.

PubMed

Karam, Pascal R; Dukhin, Andrei; Pennathur, Sumita

2017-05-01

We have developed a novel microchannel geometry that allows us to perform simple DC electrophoresis to measure the electrophoretic mobility and zeta potential of analytes and particles. In standard capillary geometries, mobility measurements using DC fields are difficult to perform. Specifically, measurements in open capillaries require knowledge of the hard to measure and often dynamic wall surface potential. Although measurements in closed capillaries eliminate this requirement, the measurements must be performed at infinitesimally small regions of zero flow where the pressure driven-flow completely cancels the electroosmotic flow (Komagata Planes). Furthermore, applied DC fields lead to electrode polarization, further questioning the reliability and accuracy of the measurement. In contrast, our geometry expands and moves the Komagata planes to where velocity gradients are at a minimum, and thus knowledge of the precise location of a Komagata plane is not necessary. Additionally, our microfluidic device prevents electrode polarization because of fluid recirculation around the electrodes. We fabricated our device using standard MEMS fabrication techniques and performed electrophoretic mobility measurements on 500 nm fluorescently tagged polystyrene particles at various buffer concentrations. Results are comparable to two different commercial dynamic light scattering based particle sizing instruments. We conclude with guidelines to further develop this robust electrophoretic tool that allows for facile and efficient particle characterization. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of a new hand-held device for exhaled nitric oxide measurement in adults and children

PubMed Central

Alving, K; Janson, C; Nordvall, L

2006-01-01

Background Exhaled nitric oxide (NO) measurement has been shown to be a valuable tool in the management of patients with asthma. Up to now, most measurements have been done with stationary, chemiluminescence-based NO analysers, which are not suitable for the primary health care setting. A hand-held NO analyser which simplifies the measurement would be of value both in specialized and primary health care. In this study, the performance of a new electrochemical hand-held device for exhaled NO measurements (NIOX MINO) was compared with a standard stationary chemiluminescence unit (NIOX). Methods A total of 71 subjects (6–60 years; 36 males), both healthy controls and atopic patients with and without asthma were included. The mean of three approved exhalations (50 ml/s) in each device, and the first approved measurement in the hand-held device, were compared with regard to NO readings (Bland-Altman plots), measurement feasibility (success rate with 6 attempts) and repeatability (intrasubject SD). Results Success rate was high (≥ 84%) in both devices for both adults and children. The subjects represented a FENO range of 8–147 parts per billion (ppb). When comparing the mean of three measurements (n = 61), the median of the intrasubject difference in exhaled NO for the two devices was -1.2 ppb; thus generally the hand-held device gave slightly higher readings. The Bland-Altman plot shows that the 95% limits of agreement were -9.8 and 8.0 ppb. The intrasubject median difference between the NIOX and the first approved measurement in the NIOX MINO was -2.0 ppb, and limits of agreement were -13.2 and 10.2 ppb. The median repeatability for NIOX and NIOX MINO were 1.1 and 1.2 ppb, respectively. Conclusion The hand-held device (NIOX MINO) and the stationary system (NIOX) are in clinically acceptable agreement both when the mean of three measurements and the first approved measurement (NIOX MINO) is used. The hand-held device shows good repeatability, and it can be used successfully on adults and most children. The new hand-held device will enable the introduction of exhaled NO measurements into the primary health care. PMID:16626491

Pre-clinical validation of a new intra-operative "dual beam Doppler" blood flowmeter in an artificial circuit.

PubMed

Cikirikcioglu, Mustafa; Cikirikcioglu, Y Banu; Khabiri, Ebrahim; Djebaili, M Karim; Kalangos, Afksendiyos; Walpoth, Beat H

2006-01-01

Intra-operative flow measurement during coronary or peripheral bypass operations is helpful for ruling out technical failures and for prediction of complication and patency rates. Preclinical validation of the flowmeters is required in order to rely on the intra-operatively measured results. The aim of this study is to evaluate a new "dual beam Doppler" blood flowmeter before clinical application and to compare it with the established "transit time flow measure-ment" technique in an artificial circuit. Measurements were performed in an experimental flow model using pig blood and pig arteries. Three different flowmeters were used: Quantix OR (dual beam doppler flowmeter), CardioMed (transit time flowmeter), and Transonic (transit time flowmeter). Three validation tests were performed to assess correlation, precision, and repeatability of devices. (1) Correlation and agreement analysis was performed with various flow amounts (10-350 mL/min) (n = 160). (2) Device reproducibility and measurement stability were tested with a constant flow (flow amount = 300 mL/min) (n = 30). (3) A user accuracy test (intra- and inter-observer variability) was performed by 5 different observers with a constant flow (flow amount = 205 mL/min) (n = 75). Time collected true flow was used as a reference method in all steps and all tests were performed in a blind manner. Results are shown as mean values +/- standard deviations. Pear-son's correlation and Bland-Altman plot analyses were used to compare measurements. The mean flow was 167 +/- 98 mL/min for true flow and 162 +/- 94 mL/min, 165 +/- 94 mL/min, and 166 +/- 100 mL/min for Quantix OR, CardioMed, and Transonic, respectively. Correlation coefficients between Quantix OR, Medi-Stim, Transonic, and time collected true flow were over 0.98 (P = .01). Most of the measured results ( > 90%) were between +/- 1.96 SD agreement limits in Bland and Altman plot analysis. All devices showed good results in the reproducibility test. During the user accuracy test, larger variance changes were observed between intra- and inter-observer results with the dual beam Doppler flowmeter compared to the 2 used transit time flowmeters when used for single sided vessel access without stabilization device (available from the manufacturer). All 3 tested flowmeters showed an excellent correlation to the true flow in an artificial circuit and the accuracy of the tested devices was within agreement limits. Reproducibility of all devices was good and linear. The new dual beam Doppler flow measurement technique compares favorably to the classic transit time method. Clinical use may depend on operator, location, and condition, thus more studies may be required to ensure uniform results using the currently available blood flow measurement devices.

Comparative ex vivo evaluation of two electronic percussive testing devices measuring the stability of dental implants.

PubMed

Geckili, Onur; Bilhan, Hakan; Cilingir, Altug; Bilmenoglu, Caglar; Ates, Gokcen; Urgun, Aliye Ceren; Bural, Canan

2014-12-01

A comparative ex vivo study was performed to determine electronic percussive test values (PTVs) measured by cabled and wireless electronic percussive testing (EPT) devices and to evaluate the intra- and interobserver reliability of the wireless EPT device. Forty implants were inserted into the vertebrae and forty into the pelvis of a steer, a safe distance apart. The implants were all 4.3 mm wide and 13 mm long, from the same manufacturer. PTV of each implant was measured by four different examiners, using both EPT devices, and compared. Additionally, the intra- and interobserver reliability of the wireless EPT device was evaluated. Statistically significant differences (P <0.05) were observed between PTVs made by the two EPT devices. PTVs measured by the wireless EPT device were significantly higher than the cabled EPT device (P <0.05), indicating lower implant stability. The intraobserver reliability of the wireless EPT device was evaluated as excellent for the measurements in type II bone and good-to-excellent in type IV bone; interobserver reliability was evaluated as fair-to-good in both bone types. The wireless EPT device gives PTVs higher than the cabled EPT device, indicating lower implant stability, and its inter- and intraobserver reliability is good and acceptable.

The application of robotics to microlaryngeal laser surgery.

PubMed

Buckmire, Robert A; Wong, Yu-Tung; Deal, Allison M

2015-06-01

To evaluate the performance of human subjects, using a prototype robotic micromanipulator controller in a simulated, microlaryngeal operative setting. Observational cross-sectional study. Twenty-two human subjects with varying degrees of laser experience performed CO2 laser surgical tasks within a simulated microlaryngeal operative setting using an industry standard manual micromanipulator (MMM) and a prototype robotic micromanipulator controller (RMC). Accuracy, repeatability, and ablation consistency measures were obtained for each human subject across both conditions and for the preprogrammed RMC device. Using the standard MMM, surgeons with >10 previous laser cases performed superior to subjects with fewer cases on measures of error percentage and cumulative error (P = .045 and .03, respectively). No significant differences in performance were observed between subjects using the RMC device. In the programmed (P/A) mode, the RMC performed equivalently or superiorly to experienced human subjects on accuracy and repeatability measures, and nearly an order of magnitude better on measures of ablation consistency. The programmed RMC performed significantly better for repetition error when compared to human subjects with <100 previous laser cases (P = .04). Experienced laser surgeons perform better than novice surgeons on tasks of accuracy and repeatability using the MMM device but roughly equivalently using the novel RMC. Operated in the P/A mode, the RMC performs equivalently or superior to experienced laser surgeons using the industry standard MMM for all measured parameters, and delivers an ablation consistency nearly an order of magnitude better than human laser operators. NA. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Phototransistors Development and their Applications to Lidar

NASA Technical Reports Server (NTRS)

Abedin, M. N.; Refaat, Tamer F.; Ismail, Syed; Singh, Upendra N.

2007-01-01

Custom-designed two-micron phototransistors have been developed using Liquid Phase Epitaxy (LPE), Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) techniques under Laser Risk Reduction Program (LRRP). The devices were characterized in the Detector Characterization Laboratory at NASA Langley Research Center. It appears that the performance of LPE- and MBE-grown phototransistors such as responsivity, noise-equivalent-power, and gain, are better than MOCVD-grown devices. Lidar tests have been conducted using LPE and MBE devices under the 2-micrometer CO2 Differential Absorption Lidar (DIAL) Instrument Incubator Program (IIP) at the National Center for Atmospheric Research (NCAR), Boulder, Colorado. The main focus of these tests was to examine the phototransistors performances as compared to commercial InGaAs avalanche photodiode by integrating them into the Raman-shifted Eye-safe Aerosol Lidar (REAL) operating at 1.543 micrometers. A simultaneous measurement of the atmospheric backscatter signals using the LPE phototransistors and the commercial APD demonstrated good agreement between these two devices. On the other hand, simultaneous detection of lidar backscatter signals using MBE-grown phototransistor and InGaAs APD, showed a general agreement between these two devices with a lower performance than LPE devices. These custom-built phototransistors were optimized for detection around 2-micrometer wavelength while the lidar tests were performed at 1.543 micrometers. Phototransistor operation at 2-micron will improve the performance of a lidar system operating at that wavelength. Measurements include detecting hard targets (Rocky Mountains), atmospheric structure consisting of cirrus clouds and boundary layer. These phototransistors may have potential for high sensitivity differential absorption lidar measurements of carbon dioxide and water vapor at 2.05-micrometers and 1.9-micrometers, respectively.

Development of an Optical Device to Investigatechlorophyll Content of Tomato Leaves

NASA Astrophysics Data System (ADS)

Cui, Di; Li, Minzan; Li, Xiuhua

Chlorophyll content is an important indication for evaluating crop growth status and predicting crop yield. The NDVI (Normalized Difference Vegetation Index) is commonly used as an indicator in practical crop healthy monitoring. Hence, a spectroscopy-based device for indirectly measuring crop growth conditions in terms of NDVI is developed. This device consists of four channels: two are designed to measure the intensity of the sunlight and the other two are used to measure the reflected light from the crop canopy at the same time. An electronic control unit was designed to control the sensing and data recording processes, as well as to calculate the NDVI based on the sensed data. The measurable two wavelengths are 610 nm and 1220 nm. A series validation tests, comparing the measurement result against spectroradiometer readings, are conducted to evaluate the performance of the device. Leaf samples are collected to measure chlorophyll contents in laboratory. The correlation coefficient between the NDVI readings from the developed device and the chlorophyll content data measured by the UV-VIS Spectrophotometer reaches 0.81, which shows that the device can be used in practical crop management.

Thermoreflectance microscopy measurements of the Joule heating characteristics of high- Tc superconducting terahertz emitters

NASA Astrophysics Data System (ADS)

Kashiwagi, Takanari; Tanaka, Taiga; Watanabe, Chiharu; Kubo, Hiroyuki; Komori, Yuki; Yuasa, Takumi; Tanabe, Yuki; Ota, Ryusei; Kuwano, Genki; Nakamura, Kento; Tsujimoto, Manabu; Minami, Hidetoshi; Yamamoto, Takashi; Klemm, Richard A.; Kadowaki, Kazuo

2017-12-01

Joule heating is the central issue in order to develop high-power and high-performance terahertz (THz) emission from mesa devices employing the intrinsic Josephson junctions in a layered high transition-temperature Tc superconductor. Here, we describe a convenient local thermal measurement technique using charge-coupled-device-based thermoreflectance microscopy, with the highest spatial resolution to date. This technique clearly proves that the relative temperature changes of the mesa devices between different bias points on the current-voltage characteristics can be measured very sensitively. In addition, the heating characteristics on the surface of the mesa devices can be detected more directly without any special treatment of the mesa surface such as previous coatings with SiC micro-powders. The results shown here clearly indicate that the contact resistance strongly affects the formation of an inhomogeneous temperature distribution on the mesa structures. Since the temperature and sample dependencies of the Joule heating characteristics can be measured quickly, this simple thermal evaluation technique is a useful tool to check the quality of the electrical contacts, electrical wiring, and sample defects. Thus, this technique could help to reduce the heating problems and to improve the performance of superconducting THz emitter devices.

Determination of repeatability of kinect sensor.

PubMed

Bonnechère, Bruno; Sholukha, Victor; Jansen, Bart; Omelina, Lubos; Rooze, Marcel; Van Sint Jan, Serge

2014-05-01

The Kinect™ (Microsoft™, Redmond, WA) sensor, originally developed for gaming purposes, may have interesting possibilities for other fields such as posture and motion assessment. The ability of the Kinect sensor to perform biomechanical measurements has previously been studied and shows promising results. However, interday repeatability of the device is still not known. This study assessed the intra- and interday repeatability of the Kinect sensor compared with a standard stereophotogrammetric device during posture assessment for measuring segment lengths. Forty subjects took part in the study. Five motionless captures were performed in one session to assess posture. Data were simultaneously recorded with both devices. Similar intraclass correlations coefficient (ICC) values were found for intraday (ICC=0.94 for the Kinect device and 0.98 for the stereophotogrammetric device) and interday (ICC=0.88 and 0.87, respectively) repeatability. Results of this study suggest that a cost-effective, easy-to-use, and portable single markerless camera offers the same repeatability during posture assessment as an expensive, time-consuming, and nontransportable marker-based device.

Evaluation of a device for standardized measurements of reading performance in a prepresbyopic population.

PubMed

Arad, Tschingis; Baumeister, Martin; Bühren, Jens; Kohnen, Thomas

2017-04-20

Automated measurements of reading performance are required for clinical trials involving presbyopia-correcting surgery options. Repeatability of a testing device for reading (Salzburg Reading Desk) was evaluated in a prepresbyopic population. Subjective reading performance of 50 subjects divided into 2 age groups (23-30 years and 38-49 years) with distance-corrected eyes was investigated with different log-scaled reading charts. At study entry, refractive parameters were measured and distance visual acuity assessed. Two standardized binocular measurements were performed for each subject (32.24 ± 9.87 days apart [mean ± SD]). The repeatability of the tests was estimated using correlation coefficients, Wilcoxon signed-rank test, and Bland-Altman method. The test parameters at both maximum reading rate (MRR) measurements demonstrate a strong relationship of age group 2 subjects (correlation coefficient [r] = 0.74 p = 10-4) and of younger subjects (age group 1: r = 0.69, p = 10-4). Prepresbyopic subjects of age group 2 showed moderate results for near reading distance (r = 0.67, p = 10-4); by contrast, younger subjects had poorer results (r = 0.55, p = 10-3). The Wilcoxon signed-rank test revealed agreement between measurements and Bland-Altman plots showed a wide data spread for MRR and near reading distance in both groups. The device measures repeatedly selected reading performance parameters of near real world conditions, such as MRR, in prepresbyopic populations if several factors are taken into account. The option to choose preferred distance leads to more variance in measuring repeated reading performance. German Clinical Trials Register (DRKS) registration reference number: DRKS00000784.

En Face Optical Coherence Tomography Angiography Imaging Versus Fundus Photography in the Measurement of Choroidal Nevi.

PubMed

Lee, Michele D; Kaidonis, Georgia; Kim, Alice Y; Shields, Ryan A; Leng, Theodore

2017-09-01

Choroidal nevi are common benign intraocular tumors with a small risk of malignant transformation. This retrospective study investigates the use of en face spectral-domain optical coherence tomography angiography (SD-OCTA) in determining the clinical features and measurement of choroidal nevi. Patients with choroidal nevi were imaged with both OCTA and a fundus photography device. Greatest longitudinal dimension (GLD), perpendicular dimension (PD), and the GLD/PD ratio were assessed on each device. Inter-device variation and intra- and inter-rater reliability analyses were performed. Fourteen patients with choroidal nevi were included. No significant difference between the GLD/PD ratio as measured by all three devices was found (Chi-square = 2.8, 2 df, P = .247). Intraclass correlation coefficients were greater than 0.7 for repeated measures on all devices, suggesting good repeatability and reproducibility. This study demonstrated inter-device consistency and high intra- and inter-rater reliability when measuring choroidal nevi. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:741-747.]. Copyright 2017, SLACK Incorporated.

Screening of Potential Landing Gear Noise Control Devices at Virginia Tech For QTD II Flight Test

NASA Technical Reports Server (NTRS)

Ravetta, Patricio A.; Burdisso, Ricardo A.; Ng, Wing F.; Khorrami, Mehdi R.; Stoker, Robert W.

2007-01-01

In support of the QTD II (Quiet Technology Demonstrator) program, aeroacoustic measurements of a 26%-scale, Boeing 777 main landing gear model were conducted in the Virginia Tech Stability Tunnel. The objective of these measurements was to perform risk mitigation studies on noise control devices for a flight test performed at Glasgow, Montana in 2005. The noise control devices were designed to target the primary main gear noise sources as observed in several previous tests. To accomplish this task, devices to reduce noise were built using stereo lithography for landing gear components such as the brakes, the forward cable harness, the shock strut, the door/strut gap and the lower truck. The most promising device was down selected from test results. In subsequent stages, the initial design of the selected lower truck fairing was improved to account for all the implementation constraints encountered in the full-scale airplane. The redesigned truck fairing was then retested to assess the impact of the modifications on the noise reduction potential. From extensive acoustic measurements obtained using a 63-element microphone phased array, acoustic source maps and integrated spectra were generated in order to estimate the noise reduction achievable with each device.

Using a Communication Model to Collect Measurement Data through Mobile Devices

PubMed Central

Bravo, José; Villarreal, Vladimir; Hervás, Ramón; Urzaiz, Gabriel

2012-01-01

Wireless systems and services have undergone remarkable development since the first mobile phone system was introduced in the early 1980s. The use of sensors in an Ambient Intelligence approach is a great solution in a medical environment. We define a communication architecture to facilitate the information transfer between all connected devices. This model is based in layers to allow the collection of measurement data to be used in our framework monitoring architecture. An overlay-based solution is built between network elements in order to provide an efficient and highly functional communication platform that allows the connection of a wide variety of devices and technologies, and serves also to perform additional functions such as the possibility to perform some processing in the network that may help to improve overall performance. PMID:23012542

Optoelectronic device for the measurement of the absolute linear position in the micrometric displacement range

NASA Astrophysics Data System (ADS)

Morlanes, Tomas; de la Pena, Jose L.; Sanchez-Brea, Luis M.; Alonso, Jose; Crespo, Daniel; Saez-Landete, Jose B.; Bernabeu, Eusebio

2005-07-01

In this work, an optoelectronic device that provides the absolute position of a measurement element with respect to a pattern scale upon switch-on is presented. That means that there is not a need to perform any kind of transversal displacement after the startup of the system. The optoelectronic device is based on the process of light propagation passing through a slit. A light source with a definite size guarantees the relation of distances between the different elements that constitute our system and allows getting a particular optical intensity profile that can be measured by an electronic post-processing device providing the absolute location of the system with a resolution of 1 micron. The accuracy of this measuring device is restricted to the same limitations of any incremental position optical encoder.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, J.P.; Maxwell, R.L.; Wright, L.J.

A biometric identification device is an automatic device that can verify a person's identity from a measurement of a physical feature or repeatable action of the individual. A reference measurement of the biometric is obtained when the individual is enrolled on the device. Subsequent verifications are made by comparing the submitted biometric feature against the reference sample. Sandia Laboratories has been evaluating the relative performance of several identity verifiers, using volunteer test subjects. Sandia testing methods and results are discussed.

High-Performance Sensors Based on Resistance Fluctuations of Single-Layer-Graphene Transistors.

PubMed

Amin, Kazi Rafsanjani; Bid, Aveek

2015-09-09

One of the most interesting predicted applications of graphene-monolayer-based devices is as high-quality sensors. In this article, we show, through systematic experiments, a chemical vapor sensor based on the measurement of low-frequency resistance fluctuations of single-layer-graphene field-effect-transistor devices. The sensor has extremely high sensitivity, very high specificity, high fidelity, and fast response times. The performance of the device using this scheme of measurement (which uses resistance fluctuations as the detection parameter) is more than 2 orders of magnitude better than a detection scheme in which changes in the average value of the resistance is monitored. We propose a number-density-fluctuation-based model to explain the superior characteristics of a noise-measurement-based detection scheme presented in this article.

An evaluation of strain measuring devices for ceramic composites

NASA Technical Reports Server (NTRS)

Gyekenyesi, John Z.; Bartolotta, Paul A.

1991-01-01

A series of tensile tests was conducted on SiC/reaction bonded silicon nitrides (RBSN) composites using different methods of strain measurement. The tests were used to find the optimum strain sensing device for use with continuous fiber reinforced ceramic matrix composites in ambient and high temperature environments. Bonded resistance gages were found to offer excellent performance for room temperature tests. The clip-on gage offers the same performance, but less time is required for mounting it to the specimen. Low contact force extensometers track the strain with acceptable results at high specimen temperatures. Silicon carbide rods with knife edges are preferred. The edges must be kept sharp. The strain measuring devices should be mounted on the flat side of the specimen. This is in contrast to mounting on the rough thickness side.

An evaluation of strain measuring devices for ceramic composites

NASA Technical Reports Server (NTRS)

Gyekenyesi, John Z.; Bartolotta, Paul A.

1992-01-01

A series of tensile tests were conducted on SiC/RBSN composites using different methods of strain measurement. The tests were used to find the optimum strain sensing device for use with continuous fiber reinforced ceramic matrix composites in ambient and high temperature environments. Bonded resistance strain gages were found to offer excellent performance for room temperature tests. The clip-on gage offers the same performance but significantly less time is required for mounting it to the specimen. Low contact force extensometers track the strain with acceptable results at high specimen temperatures. Silicon carbide rods with knife edges are preferred. The edges must be kept sharp. The strain measuring devices should be mounted on the flat side of the specimen. This is in contrast to mounting on the rough thickness side.

W-state Analyzer and Multi-party Measurement-device-independent Quantum Key Distribution

PubMed Central

Zhu, Changhua; Xu, Feihu; Pei, Changxing

2015-01-01

W-state is an important resource for many quantum information processing tasks. In this paper, we for the first time propose a multi-party measurement-device-independent quantum key distribution (MDI-QKD) protocol based on W-state. With linear optics, we design a W-state analyzer in order to distinguish the four-qubit W-state. This analyzer constructs the measurement device for four-party MDI-QKD. Moreover, we derived a complete security proof of the four-party MDI-QKD, and performed a numerical simulation to study its performance. The results show that four-party MDI-QKD is feasible over 150 km standard telecom fiber with off-the-shelf single photon detectors. This work takes an important step towards multi-party quantum communication and a quantum network. PMID:26644289

Image quality degradation by light-scattering processes in high-performance display devices for medical imaging

NASA Astrophysics Data System (ADS)

Badano, Aldo

1999-11-01

This thesis addresses the characterization of light scattering processes that degrade image quality in high performance electronic display devices for digital radiography. Using novel experimental and computational tools, we study the lateral diffusion of light in emissive display devices that causes extensive veiling glare and significant reduction of the physical contrast. In addition, we examine the deleterious effects of ambient light reflections that affect the contrast of low luminance regions, and superimpose unwanted structured signal. The analysis begins by introducing the performance limitations of the human visual system to define high fidelity requirements. It is noted that current devices severely suffer from image quality degradation due to optical transport processes. To model the veiling glare and reflectance characteristics of display devices, we introduce a Monte Carlo light transport simulation code, DETECT-II, that tracks individual photons through multiple scattering events. The simulation accounts for the photon polarization state at each scattering event, and provides descriptions for rough surfaces and thin film coatings. A new experimental method to measure veiling glare is described next, based on a conic collimated probe that minimizes contamination from bright areas. The measured veiling glare ratio is taken to be the luminance in the surrounding bright field divided by the luminance in the dark circle. We show that veiling glare ratios in the order of a few hundreds can be measured with an uncertainty of a few percent. The veiling glare response function is obtained by measuring the small spot contrast ratio of test patterns having varying dark spot radius. Using DETECT-II, we then estimate the ring response functions for a high performance medical imaging monitor of current design, and compare the predictions of the model with the experimentally measured response function. The data presented in this thesis demonstrate that although absorption in the faceplate of high performance monochrome cathode-ray tube monitors have reduced glare, a black matrix design is needed for high fidelity applications. For a high performance medical imaging monitor with anti-reflective coating, the glare ratio for a 1 cm diameter dark spot was measured to be 240. Finally, we introduce experimental techniques for measurements of specular and diffuse display reflectance, and we compare measured reflection coefficients with Monte Carlo estimates. A specular reflection coefficient of 0.0012, and a diffuse coefficient of 0.005 nits/lux are required to minimize degradation from ambient light in rooms with 100 lux illumination. In spite of having comparable reflection coefficients, the low maximum luminance of current devices worsens the effect of ambient light reflections when compared to radiographic film. Flat panel technologies with optimized designs can perform even better than film due to a thin faceplate, increased light absorption, and high brightness.

Large cooling differentials and high heat flux capability with p-type Bi2Te3/Sb2Te3 and n-type Bi2Te3/Bi2SexTe3-x Superlattice Thermoelectric Devices

NASA Astrophysics Data System (ADS)

Bulman, Gary; Siivola, Ed; Wiitala, Ryan; Grant, Brian; Pierce, Jonathan; Venkatasubramanian, Rama

2007-03-01

Thin film superlattice (SL) based thermoelectric (TE) devices offer the potential for improved efficiency and high heat flux cooling over conventional bulk materials. Recently, we have demonstrated external cooling of 55K and heat pumping capacity of 128 W/cm^2. These high heat fluxes in thin film devices, while attractive for cooling hot-spots in electronics, also make the device performance sensitive to various thermal resistances in the device structure. We will discuss advances in the cooling performance of Bi2Te3-based SL TE devices and describe a method to extract device material parameters, including thermal resistance, from measurements of their δT-I-V characteristics. These parameters will be compared to values obtained through Hall and Seebeck coefficient measurement on epitaxial materials. Results will be presented for both single couple and multi-couple modules, as well as multi-stage cascaded devices made with these materials. Single stage cooling couples with δTmax of 57.8K (Tc˜242K) and multi-stage modules with δTmax˜92.2K (Tc˜209K) have been measured. G.E. Bulman, E. Siivola, B. Shen and R. Venkatasubramanian, Appl. Phys. Lett. 89, 122117 (2006).

Optimization of flexible substrate by gradient elastic modulus design for performance improvement of flexible electronic devices

NASA Astrophysics Data System (ADS)

Xia, Minggang; Liang, Chunping; Hu, Ruixue; Cheng, Zhaofang; Liu, Shiru; Zhang, Shengli

2018-05-01

It is imperative and highly desirable to buffer the stress in flexible electronic devices. In this study, we designed and fabricated lamellate poly(dimethylsiloxane) (PDMS) samples with gradient elastic moduli, motivated by the protection of the pomelo pulp by its skin, followed by the measurements of their elastic moduli. We demonstrated that the electrical and fatigue performances of a Ag-nanowire thin film device on the PDMS substrate with a gradient elastic modulus are significantly better than those of a device on a substrate with a monolayer PDMS. This study provides a robust scheme to effectively protect flexible electronic devices.

PV Calibration Insights | NREL

Science.gov Websites

PV Calibration Insights PV Calibration Insights The Photovoltaic (PV) Calibration Insights blog will provide updates on the testing done by the NREL PV Device Performance group. This NREL research group measures the performance of any and all technologies and sizes of PV devices from around the world

Characteristics of enhanced-mode AlGaN/GaN MIS HEMTs for millimeter wave applications

NASA Astrophysics Data System (ADS)

Lee, Jong-Min; Ahn, Ho-Kyun; Jung, Hyun-Wook; Shin, Min Jeong; Lim, Jong-Won

2017-09-01

In this paper, an enhanced-mode (E-mode) AlGaN/GaN high electron mobility transistor (HEMT) was developed by using 4-inch GaN HEMT process. We designed and fabricated Emode HEMTs and characterized device performance. To estimate the possibility of application for millimeter wave applications, we focused on the high frequency performance and power characteristics. To shift the threshold voltage of HEMTs we applied the Al2O3 insulator to the gate structure and adopted the gate recess technique. To increase the frequency performance the e-beam lithography technique was used to define the 0.15 um gate length. To evaluate the dc and high frequency performance, electrical characterization was performed. The threshold voltage was measured to be positive value by linear extrapolation from the transfer curve. The device leakage current is comparable to that of the depletion mode device. The current gain cut-off frequency and the maximum oscillation frequency of the E-mode device with a total gate width of 150 um were 55 GHz and 168 GHz, respectively. To confirm the power performance for mm-wave applications the load-pull test was performed. The measured power density of 2.32 W/mm was achieved at frequencies of 28 and 30 GHz.

75 FR 33303 - Comment Sought on Measurement of Mobile Broadband Network Performance and Coverage

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-11

...; DA 10-988] Comment Sought on Measurement of Mobile Broadband Network Performance and Coverage AGENCY... broadband services. The Bureau seeks comment on whether and how to pursue a measurement program for mobile... and coverage, and continue to work with measurement companies, application designers, device...

Identification and validation of nebulized aerosol devices for sputum induction

PubMed Central

Davidson, Warren J; Dennis, John; The, Stephanie; Litoski, Belinda; Pieron, Cora; Leigh, Richard

2014-01-01

Induced sputum cell count measurement has proven reliability for evaluating airway inflammation in patients with asthma and other airway diseases. Although the use of nebulizer devices for sputum induction is commonplace, they are generally labelled as single-patient devices by the manufacturer and, therefore, cannot be used for multiple patients in large clinical sputum induction programs due to infect ion-control requirements. Accordingly, this study investigated the aerosol characteristics of alternative devices that could be used in such programs. BACKGROUND: Induced sputum cell counts are a noninvasive and reliable method for evaluating the presence, type and degree of airway inflammation in patients with asthma. Currently, standard nebulizer devices used for sputum induction in multiple patients are labelled as single-patient devices by the manufacturer, which conflicts with infection prevention and control requirements. As such, these devices cannot feasibly be used in a clinical sputum induction program. Therefore, there is a need to identify alternative nebulizer devices that are either disposable or labelled for multi-patient use. OBJECTIVE: To apply validated rigorous, scientific testing methods to identify and validate commercially available nebulizer devices appropriate for use in a clinical sputum induction program. METHODS: Measurement of nebulized aerosol output and size for the selected nebulizer designs followed robust International Organization for Standardization methods. Sputum induction using two of these nebulizers was successfully performed on 10 healthy adult subjects. The cytotechnologist performing sputum cell counts was blinded to the type of nebulizer used. RESULTS: The studied nebulizers had variable aerosol outputs. The AeroNeb Solo (Aerogen, Ireland), Omron NE-U17 (Omron, Japan) and EASYneb II (Flaem Nuova, Italy) systems were found to have similar measurements of aerosol size. There was no significant difference in induced sputum cell results between the AeroNeb Solo and EASYneb II devices. DISCUSSION: There is a need for rigorous, scientific evaluation of nebulizer devices for clinical applications, including sputum induction, for measurement of cell counts. CONCLUSION: The present study was the most comprehensive analysis of different nebulizer devices for sputum induction to measure cell counts, and provides a framework for appropriate evaluation of nebulizer devices for induced sputum testing. PMID:24288700

A portable device for calibration of autocollimators with nanoradian precision

NASA Astrophysics Data System (ADS)

Yandayan, Tanfer

2017-09-01

A portable device has been developed in TUBITAK UME to calibrate high precision autocollimators with nanoradian precision. The device can operate in the range of +/-4500" which is far enough for the calibration of the available autocollimators and can generate ultra-small angles in measurement steps of 0.0005" (2.5 nrad). Description of the device with the performance tests using the calibrated precise autocollimators and novel methods will be reported. The test results indicate that the device is a good candidate for application to on-site/in-situ calibration of autocollimators with expanded uncertainties of 0.01" (50 nrad) particularly those used in slope measuring profilers.

Taking Impressions of Hidden Cavity Walls

NASA Technical Reports Server (NTRS)

Burley, D.; Mayer, W.

1987-01-01

Lightweight, portable internal-molding device makes it possible to measure radii of, or examine contours of, passageways in hidden or complicated cavities. With device, measurements made in field, without returning assemblies to shop or laboratory for inspection. Molding head expands when compressed air applied. Inflatable tubes around head perform dual sealing and aligning function.

A novel portable device to measure the temperature of both the inner and the outer tubes of a parabolic receiver in the field

NASA Astrophysics Data System (ADS)

Hermoso, J. L. Navarro; Espinosa-Rueda, Guillermo; Martinez, Noelia; Heras, Carlos; Osta, Marta

2016-05-01

The performance of parabolic trough (PT) receiver tubes (RT) has a direct impact on Solar Thermal Energy (STE) plant production. As a result, one major need of operation and maintenance (O&M) in STE plants is to monitor the state of the receiver tube as a key element in the solar field. However the lack of specific devices so far has limited the proper evaluation of operating receiver tubés thermal performance. As a consequence non-accurate approximations have been accepted until now using infrared thermal images of the glass outer tube. In order to fulfill this need, Abengoa has developed a unique portable device for evaluating the thermal performance and vacuum state of parabolic trough receiver tubes placed in the field. The novel device described in this paper, simultaneously provides the temperature of both the inner steel tube and the outer glass tube enabling a check on manufacturers specifications. The on-field evaluation of any receiver tube at any operating temperature has become possible thanks to this new measuring device. The features and usability of this new measurement system as a workable portable device in operating solar fields provide a very useful tool for all companies in the sector contributing to technology progress. The originality of the device, patent pending P201431969, is not limited to the CSP sector, also having scientific significance in the general measuring instruments field. This paper presents the work carried out to develop and validate the device, also detailing its functioning properties and including the excellent results obtained in the laboratory to determine its accuracy and standard deviation. This information was validated with data collected by O&M teams using this instrument in a commercial CSP plant. The relevance of the device has been evidenced by evaluating a wide sample of RT and the results are discussed in this paper. Finally, all the on field collected data is used to demonstrate the high impact that using this unique portable device will have on a parabolic trough solar power plant.

Development of a novel precision instrument for high-resolution simultaneous normal and shear force measurements between small planar samples

NASA Astrophysics Data System (ADS)

Lundstrom, Troy; Clark, William; Jalili, Nader

2017-05-01

In the design and development of end effector pads for silicon wafer handling robots, it is imperative that the static friction/adhesion force properties of the pads with respect to a variety of planar surfaces be characterized. In this work, the overall design, calibration, and data acquisition procedure of an instrument developed for performing these measurements on small (<10 mm × 10 mm) planar samples is presented. This device was used to perform adhesion/maximum shear force measurements on polydimethylsiloxane, a silicon wafer, and custom carbon nanotubes forest surfaces. The device was successfully able to measure an effective, mean profile adhesion force of 715 μN between a silicon wafer and a polydimethylsiloxane (2.768 × 10-6 m2) sample. In addition, a nonlinear maximum shear over normal force relationship was also measured between custom carbon nanotubes forest and the silicon wafer surfaces. The maximum shear over a normal force coefficient was found to decrease with increasing initial normal force. Currently, there are numerous devices for measuring normal/shear forces at the nano/micro- and macroscales; however, this device allows for the consistent measurement of these same types of forces on components with surface dimensions ranging from 0.1 mm to 10 mm.

A wireless handheld probe with spectrally constrained evolution strategies for diffuse optical imaging of tissue

NASA Astrophysics Data System (ADS)

Flexman, M. L.; Kim, H. K.; Stoll, R.; Khalil, M. A.; Fong, C. J.; Hielscher, A. H.

2012-03-01

We present a low-cost, portable, wireless diffuse optical imaging device. The handheld device is fast, portable, and can be applied to a wide range of both static and dynamic imaging applications including breast cancer, functional brain imaging, and peripheral artery disease. The continuous-wave probe has four near-infrared wavelengths and uses digital detection techniques to perform measurements at 2.3 Hz. Using a multispectral evolution algorithm for chromophore reconstruction, we can measure absolute oxygenated and deoxygenated hemoglobin concentration as well as scattering in tissue. Performance of the device is demonstrated using a series of liquid phantoms comprised of Intralipid®, ink, and dye.

Validity and reliability of a new ankle dorsiflexion measurement device.

PubMed

Gatt, Alfred; Chockalingam, Nachiappan

2013-08-01

The assessment of the maximum ankle dorsiflexion angle is an important clinical examination procedure. Evidence shows that the traditional goniometer is highly unreliable, and various designs of goniometers to measure the maximum ankle dorsiflexion angle rely on the application of a known force to obtain reliable results. Hence, an innovative ankle dorsiflexion measurement device was designed to make this measurement more reliable by holding the foot in a selected posture without the application of a known moment. To report on the comprehensive validity and reliability testing carried out on the new device. Following validity testing, four different trials to test reliability of the ankle dorsiflexion measurement device were performed. These trials included inter-rater and intra-rater testings with a controlled moment, intra-rater reliability testing with knees flexed and extended without a controlled moment, intra-rater testing with a patient population, and inter-rater reliability testing between four raters of varying experience without controlling moment. All raters were blinded. A series of trials to test intra-rater and inter-rater reliabilities. Intra-rater reliability intraclass correlation coefficient was 0.98 and inter-rater reliability intraclass correlation coefficient (2,1) was 0.953 with a controlled moment. With uncontrolled moment, very high reliability for intra-tester was also achieved (intraclass correlation coefficient = 0.94 with knees extended and intraclass correlation coefficient = 0.95 with knees flexed). For the trial investigating test-retest reliability with actual patients, intraclass correlation coefficient of 0.99 was obtained. In the trial investigating four different raters with uncontrolled moment, intraclass correlation coefficient of 0.91 was achieved. The new ankle dorsiflexion measurement device is a valid and reliable device for measuring ankle dorsiflexion in both healthy subjects and patients, with both controlled and uncontrolled moments, even by multiple raters of varying experience when the foot is dorsiflexed to its end of range of motion. An ankle dorsiflexion measuring device has been designed to increase the reliability of ankle dorsiflexion measurement and replace the traditional goniometer. While the majority of similar devices rely on application of a known moment to perform this measurement, it has been shown that this is not required with the new ankle dorsiflexion measurement device and, rather, foot posture should be taken into consideration as this affects the maximum ankle dorsiflexion angle.

The Measurement of Airflow Using Singing Helmet That Allows Free Movement of the Jaw.

PubMed

Jiang, Jack J; Hanna, Rewais B; Willey, Malachi V; Rieves, Adam

2016-11-01

Airflow measurement is a useful method of evaluating laryngeal physiology. We introduce a noninvasive device that measures airflow without restricting jaw movement or requiring phonation into a mouthpiece, thus facilitating measurement during singing and connected speech. Validation and human subject trials were conducted. Airflow measurements were obtained from 16 male and 16 female subjects during singing, speech, and constant vowel production tasks. A similar helmet was designed by Stevens and Mead in 1968. The new device validity was evaluated by comparing the measured volume of air to a known volume of administered air using a calibration syringe. Subjects were asked to voice sustained vowels at low, medium, and high vocal intensity, read two sentences at a conversational volume, and perform different singing exercises while airflow was recorded. The device accurately and reliably measured airflow with mean airflow values falling within previously published ranges. There was an experimentally determined response time of 0.173 ± 0.014 seconds. Subjects were able to comfortably perform speech and singing exercises. Male subjects had higher airflow for all sustained vowels (P < 0.05). Airflow was higher for abduction rather than adduction sentences (P < 0.05). No other portable device has been shown to measure airflow during singing and speech while allowing for free movement of the jaw. This device provides a more natural environment to measure airflow that could be used to help evaluate laryngeal function and aid in singing training. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Characterization of perovskite solar cells: Towards a reliable measurement protocol

NASA Astrophysics Data System (ADS)

Zimmermann, Eugen; Wong, Ka Kan; Müller, Michael; Hu, Hao; Ehrenreich, Philipp; Kohlstädt, Markus; Würfel, Uli; Mastroianni, Simone; Mathiazhagan, Gayathri; Hinsch, Andreas; Gujar, Tanaji P.; Thelakkat, Mukundan; Pfadler, Thomas; Schmidt-Mende, Lukas

2016-09-01

Lead halide perovskite solar cells have shown a tremendous rise in power conversion efficiency with reported record efficiencies of over 20% making this material very promising as a low cost alternative to conventional inorganic solar cells. However, due to a differently severe "hysteretic" behaviour during current density-voltage measurements, which strongly depends on scan rate, device and measurement history, preparation method, device architecture, etc., commonly used solar cell measurements do not give reliable or even reproducible results. For the aspect of commercialization and the possibility to compare results of different devices among different laboratories, it is necessary to establish a measurement protocol which gives reproducible results. Therefore, we compare device characteristics derived from standard current density-voltage measurements with stabilized values obtained from an adaptive tracking of the maximum power point and the open circuit voltage as well as characteristics extracted from time resolved current density-voltage measurements. Our results provide insight into the challenges of a correct determination of device performance and propose a measurement protocol for a reliable characterisation which is easy to implement and has been tested on varying perovskite solar cells fabricated in different laboratories.

Apollo Spacecraft and Saturn V Launch Vehicle Pyrotechnics/Explosive Devices

NASA Technical Reports Server (NTRS)

Interbartolo, Michael

2009-01-01

The Apollo Mission employs more than 210 pyrotechnic devices per mission.These devices are either automatic of commanded from the Apollo spacecraft systems. All devices require high reliability and safety and most are classified as either crew safety critical or mission critical. Pyrotechnic devices have a wide variety of applications including: launch escape tower separation, separation rocket ignition, parachute deployment and release and electrical circuit opening and closing. This viewgraph presentation identifies critical performance, design requirements and safety measures used to ensure quality, reliability and performance of Apollo pyrotechnic/explosive devices. The major components and functions of a typical Apollo pyrotechnic/explosive device are listed and described (initiators, cartridge assemblies, detonators, core charges). The presentation also identifies the major locations and uses for the devices on: the Command and Service Module, Lunar Module and all stages of the launch vehicle.

Development and modification of a device for three-dimensional measurement of orthodontic force system: The V-bend system re-visited.

PubMed

Lai, WeiJen; Midorikawa, Yoshiyuki; Kanno, Zuisei; Takemura, Hiroshi; Suga, Kazuhiro; Soga, Kohei; Ono, Takashi; Uo, Motohiro

2016-12-01

We developed a device to evaluate the orthodontic force applied by systems requiring high operability. A life-sized, two-tooth model was designed, and the measurements were performed using a custom-made jointed attachment, referred to as an "action stick", to allow clearance for the oversized six-axis sensors. This tooth-sensor apparatus was accurately calibrated, and the error was limited. Vector analysis and rotating coordinate transformation were required to derive the force and moment at the tooth from the sensor readings. The device was then used to obtain measurements of the force and moment generated by the V-bend system. Our device was effective, providing results that were consistent with those of previous studies. This measurement device can be manufactured with force sensors of any size, and it can also be expanded to models with any number of teeth.

Non-Contact Stiffness Measurement of a Suspended Single Walled Carbon Nanotube Device

NASA Technical Reports Server (NTRS)

Zheng, Yun; Su, Chanmin; Getty, Stephanie

2010-01-01

A new nanoscale electric field sensor was developed for studying triboelectric charging in terrestrial and Martian dust devils. This sensor is capable to measure the large electric fields for large dust devils without saturation. However, to quantify the electric charges and the field strength it is critical to calibrate the mechanical stiffness of the sensor devices. We performed a technical feasibility study of the Nano E-field Sensor stiffness by a non-contact stiffness measurement method. The measurement is based on laser Doppler vibrometer measurement of the thermal noise due to energy flunctuations in the devices. The experiment method provides a novel approach to acquire data that is essential in analyzing the quantitative performance of the E-field Nano Sensor. To carry out the non-contact stiffness measurement, we fabricated a new Single-Walled Carbon Nanotube (SWCNT) E-field sensor with different SWCNTs suspension conditions. The power spectra of the thermal induced displacement in the nano E-field sensor were measured at the accuracy of picometer. The power spectra were then used to derive the mechanical stiffness of the sensors. Effect of suspension conditions on stiffness and sensor sensitivty was discussed. After combined deformation and resistivity measurement, we can compare with our laboratory testing and field testing results. This new non-contact measurement technology can also help to explore to other nano and MEMS devices in the future.

Preliminary evaluation of a novel bone-conduction device for single-sided deafness.

PubMed

Popelka, Gerald R; Derebery, Jennifer; Blevins, Nikolas H; Murray, Michael; Moore, Brian C J; Sweetow, Robert W; Wu, Ben; Katsis, Mina

2010-04-01

A new intraoral bone-conduction device has advantages over existing bone-conduction devices for reducing the auditory deficits associated with single-sided deafness (SSD). Existing bone-conduction devices effectively mitigate auditory deficits from single-sided deafness but have suboptimal microphone locations, limited frequency range, and/or require invasive surgery. A new device has been designed to improve microphone placement (in the ear canal of the deaf ear), provide a wider frequency range, and eliminate surgery by delivering bone-conduction signals to the teeth via a removable oral appliance. Forces applied by the oral appliance were compared with forces typically experienced by the teeth from normal functions such as mastication or from other appliances. Tooth surface changes were measured on extracted teeth, and transducer temperature was measured under typical use conditions. Dynamic operating range, including gain, bandwidth, and maximum output limits, were determined from uncomfortable loudness levels and vibrotactile thresholds, and speech recognition scores were measured using normal-hearing subjects. Auditory performance in noise (Hearing in Noise Test) was measured in a limited sample of SSD subjects. Overall comfort, ease of insertion, and removal and visibility of the oral appliance in comparison with traditional hearing aids were measured using a rating scale. The oral appliance produces forces that are far below those experienced by the teeth from normal functions or conventional dental appliances. The bone-conduction signal level can be adjusted to prevent tactile perception yet provide sufficient gain and output at frequencies from 250 to 12,000 Hz. The device does not damage tooth surfaces nor produce heat, can be inserted and removed easily, and is as comfortable to wear as traditional hearing aids. The new microphone location has advantages for reducing the auditory deficits caused by SSD, including the potential to provide spatial cues introduced by reflections from the pinna, compared with microphone locations for existing devices. A new approach for SSD has been proposed that optimizes microphone location and delivers sound by bone conduction through a removable oral appliance. Measures in the laboratory using normal-hearing subjects indicate that the device provides useful gain and output for SSD patients, is comfortable, does not seem to have detrimental effects on oral function or oral health, and has several advantages over existing devices. Specifically, microphone placement is optimized for reducing the auditory deficit caused by SSD, frequency bandwidth is much greater, and the system does not require surgical placement. Auditory performance in a small sample of SSD subjects indicated a substantial advantage compared with not wearing the device. Future studies will involve performance measures on SSD patients wearing the device for longer periods.

Evaluation of performance, acceptance, and compliance of an auto-injector in healthy and rheumatoid arthritic subjects measured by a motion capture system.

PubMed

Xiao, Xiao; Li, Wei; Clawson, Corbin; Karvani, David; Sondag, Perceval; Hahn, James K

2018-01-01

The study aimed to develop a motion capture system that can track, visualize, and analyze the entire performance of self-injection with the auto-injector. Each of nine healthy subjects and 29 rheumatoid arthritic (RA) patients with different degrees of hand disability performed two simulated injections into an injection pad while six degrees of freedom (DOF) motions of the auto-injector and the injection pad were captured. We quantitatively measured the performance of the injection by calculating needle displacement from the motion trajectories. The max, mean, and SD of needle displacement were analyzed. Assessments of device acceptance and usability were evaluated by a survey questionnaire and independent observations of compliance with the device instruction for use (IFU). A total of 80 simulated injections were performed. Our results showed a similar level of performance among all the subjects with slightly larger, but not statistically significant, needle displacement in the RA group. In particular, no significant effects regarding previous experience in self-injection, grip method, pain in hand, and Cochin score in the RA group were found to have an impact on the mean needle displacement. Moreover, the analysis of needle displacement for different durations of injections indicated that most of the subjects reached their personal maximum displacement in 15 seconds and remained steady or exhibited a small amount of increase from 15 to 60 seconds. Device acceptance was high for most of the questions (ie, >4; >80%) based on a 0-5-point scale or percentage of acceptance. The overall compliance with the device IFU was high for the first injection (96.05%) and reached 98.02% for the second injection. We demonstrated the feasibility of tracking the motions of injection to measure the performance of simulated self-injection. The comparisons of needle displacement showed that even RA patients with severe hand disability could properly perform self-injection with this auto-injector at a similar level with the healthy subjects. Finally, the observed high device acceptance and compliance with device IFU suggest that the system is convenient and easy to use.

Intensity noise properties of a compact laser device based on a miniaturized MOPA system for spectroscopic applications

NASA Astrophysics Data System (ADS)

Baumgärtner, S.; Juhl, S.; Opalevs, D.; Sahm, A.; Hofmann, J.; Leisching, P.; Paschke, K.

2018-02-01

We present a novel compact laser device based on a semiconductor master-oscillator power-amplifier (MOPA) emitting at 772 nm, suitable for quantum optic and spectroscopy. The optical performance of the laser device is characterized. For miniaturized lasers the thermal management is challenging, we therefore perform thermal simulations and measurements. The first demonstrator is emitting more than 3 W optical power with a linewidth below 2lMHz. Using this MOPA design also compact devices for quantum optics (e.g. rubidium atomic clock) and seed lasers for frequency conversion can be realized [1].

New Device for Intrinsic Hand Muscle Strength Measurement: An Alternative to Strain Gauge Handheld Dynamometer.

PubMed

Madhanagopal, Jagannathan; Singh, Om Prakash; Mohan, Vikram; Sathasivam, Kathiresan V; Omar, Abdul Hafidz; Abdul Kadir, Mohammed Rafiq

2017-01-01

An accurate measurement of intrinsic hand muscle strength (IHMS) is required by clinicians for effective clinical decision-making, diagnosis of certain diseases, and evaluation of the outcome of treatment. In practice, the clinicians use Intrins-o-meter and Rotterdam Intrinsic Hand Myometer for IHMS measurement. These are quite bulky, expensive, and possess poor interobserver reliability (37-52%) and sensitivity. The purpose of this study was to develop an alternative lightweight, accurate, cost-effective force measurement device with a simple electronic circuit and test its suitability for IHMS measurement. The device was constructed with ketjenblack/deproteinized natural rubber sensor, 1-MΩ potential divider, and Arduino Uno through the custom-written software. Then, the device was calibrated and tested for accuracy and repeatability within the force range of finger muscles (100 N). The 95% limit of agreement in accuracy from -1.95 N to 2.06 N for 10 to 100 N applied load and repeatability coefficient of ±1.91 N or 6.2% was achieved. Furthermore, the expenditure for the device construction was around US$ 53. For a practical demonstration, the device was tested among 16 participants for isometric strength measurement of the ulnar abductor and dorsal interossei. The results revealed that the performance of the device was suitable for IHMS measurement.

Face recognition in age related macular degeneration: perceived disability, measured disability, and performance with a bioptic device.

PubMed

Tejeria, L; Harper, R A; Artes, P H; Dickinson, C M

2002-09-01

(1) To explore the relation between performance on tasks of familiar face recognition (FFR) and face expression difference discrimination (FED) with both perceived disability in face recognition and clinical measures of visual function in subjects with age related macular degeneration (AMD). (2) To quantify the gain in performance for face recognition tasks when subjects use a bioptic telescopic low vision device. 30 subjects with AMD (age range 66-90 years; visual acuity 0.4-1.4 logMAR) were recruited for the study. Perceived (self rated) disability in face recognition was assessed by an eight item questionnaire covering a range of issues relating to face recognition. Visual functions measured were distance visual acuity (ETDRS logMAR charts), continuous text reading acuity (MNRead charts), contrast sensitivity (Pelli-Robson chart), and colour vision (large panel D-15). In the FFR task, images of famous people had to be identified. FED was assessed by a forced choice test where subjects had to decide which one of four images showed a different facial expression. These tasks were repeated with subjects using a bioptic device. Overall perceived disability in face recognition did not correlate with performance on either task, although a specific item on difficulty recognising familiar faces did correlate with FFR (r = 0.49, p<0.05). FFR performance was most closely related to distance acuity (r = -0.69, p<0.001), while FED performance was most closely related to continuous text reading acuity (r = -0.79, p<0.001). In multiple regression, neither contrast sensitivity nor colour vision significantly increased the explained variance. When using a bioptic telescope, FFR performance improved in 86% of subjects (median gain = 49%; p<0.001), while FED performance increased in 79% of subjects (median gain = 50%; p<0.01). Distance and reading visual acuity are closely associated with measured task performance in FFR and FED. A bioptic low vision device can offer a significant improvement in performance for face recognition tasks, and may be useful in reducing the handicap associated with this disability. There is, however, little evidence for a correlation between self rated difficulty in face recognition and measured performance for either task. Further work is needed to explore the complex relation between the perception of disability and measured performance.

Face recognition in age related macular degeneration: perceived disability, measured disability, and performance with a bioptic device

PubMed Central

Tejeria, L; Harper, R A; Artes, P H; Dickinson, C M

2002-01-01

Aims: (1) To explore the relation between performance on tasks of familiar face recognition (FFR) and face expression difference discrimination (FED) with both perceived disability in face recognition and clinical measures of visual function in subjects with age related macular degeneration (AMD). (2) To quantify the gain in performance for face recognition tasks when subjects use a bioptic telescopic low vision device. Methods: 30 subjects with AMD (age range 66–90 years; visual acuity 0.4–1.4 logMAR) were recruited for the study. Perceived (self rated) disability in face recognition was assessed by an eight item questionnaire covering a range of issues relating to face recognition. Visual functions measured were distance visual acuity (ETDRS logMAR charts), continuous text reading acuity (MNRead charts), contrast sensitivity (Pelli-Robson chart), and colour vision (large panel D-15). In the FFR task, images of famous people had to be identified. FED was assessed by a forced choice test where subjects had to decide which one of four images showed a different facial expression. These tasks were repeated with subjects using a bioptic device. Results: Overall perceived disability in face recognition did not correlate with performance on either task, although a specific item on difficulty recognising familiar faces did correlate with FFR (r = 0.49, p<0.05). FFR performance was most closely related to distance acuity (r = −0.69, p<0.001), while FED performance was most closely related to continuous text reading acuity (r = −0.79, p<0.001). In multiple regression, neither contrast sensitivity nor colour vision significantly increased the explained variance. When using a bioptic telescope, FFR performance improved in 86% of subjects (median gain = 49%; p<0.001), while FED performance increased in 79% of subjects (median gain = 50%; p<0.01). Conclusion: Distance and reading visual acuity are closely associated with measured task performance in FFR and FED. A bioptic low vision device can offer a significant improvement in performance for face recognition tasks, and may be useful in reducing the handicap associated with this disability. There is, however, little evidence for a correlation between self rated difficulty in face recognition and measured performance for either task. Further work is needed to explore the complex relation between the perception of disability and measured performance. PMID:12185131

Design and development of a device to measure the deformities of clubfoot.

PubMed

Khas, Kanwaljit S; Pandey, Pulak M; Ray, Alok R

2015-03-01

Clubfoot describes a range of foot abnormalities usually present at birth, in which the foot of a baby is twisted out of shape or position. In order to develop an effective treatment plan for clubfoot and/or assess the extent to which existing interventions are successful, medical practitioners need to be able to accurately measure the nature and extent of the deformity. This is typically performed using a goniometer. However, this device is only able to measure one dimension at a time. As such, a complete assessment of the condition of a foot can be extremely burdensome and time-consuming. This article describes a new device that can quickly and efficiently take several measurements on feet of various sizes and shapes. The use of this device was verified by measuring the deformities of real clubfeet. A silicone rubber clubfoot model was also used in this study to clearly illustrate the effectiveness with which the proposed device can measure the various deformities of clubfoot. It is envisaged that the use of this device will significantly reduce the time and effort orthopedists require to measure clubfoot deformities and develop and assess treatment plans. © IMechE 2015.

Non-Invasive Tension Measurement Devices for Parachute Cordage

NASA Technical Reports Server (NTRS)

Litteken, Douglas A.; Daum, Jared S.

2016-01-01

The need for lightweight and non-intrusive tension measurements has arisen alongside the development of high-fidelity computer models of textile and fluid dynamics. In order to validate these computer models, data must be gathered in the operational environment without altering the design, construction, or performance of the test article. Current measurement device designs rely on severing a cord and breaking the load path to introduce a load cell. These load cells are very reliable, but introduce an area of high stiffness in the load path, directly affecting the structural response, adding excessive weight, and possibly altering the dynamics of the parachute during a test. To capture the required data for analysis validation without affecting the response of the system, non-invasive measurement devices have been developed and tested by NASA. These tension measurement devices offer minimal impact to the mass, form, fit, and function of the test article, while providing reliable, axial tension measurements for parachute cordage.

Development and Testing of an Integrated Sandia Cooler Thermoelectric Device (SCTD).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Terry A.; Staats, Wayne Lawrence,; Leick, Michael Thomas

This report describes a FY14 effort to develop an integrated Sandia Cooler T hermoelectric D evice (SCTD) . The project included a review of feasible thermoelectric (TE) cooling applications, baseline performance testing of an existing TE device, analysis and design development of an integrated SCTD assembly, and performance measurement and validation of the integrated SCTD prototype.

Validation of a Piezoelectric Sensor Array-Based Device for Measurement of Carotid-Femoral Pulse Wave Velocity: The Philips Prototype.

PubMed

Xu, Shao-Kun; Hong, Xiang-Fei; Cheng, Yi-Bang; Liu, Chang-Yuan; Li, Yan; Yin, Bin; Wang, Ji-Guang

2018-03-01

Multiple piezoelectric pressure mechanotransducers topologized into an array might improve efficiency and accuracy in collecting arterial pressure waveforms for measurement of pulse wave velocity (PWV). In the present study, we validated a piezoelectric sensor array-based prototype (Philips) against the validated and clinically widely used Complior device (Alam Medical). We recruited 33 subjects with a wide distribution of PWV. For the validation, PWV was measured sequentially with the Complior device (four times) and the Philips prototype (three times). With the 99 paired PWV values, we investigated the agreement between the Philips prototype and the Complior device using Pearson correlation analysis and Bland-Altman plot. We also performed analysis on the determinants and reproducibility of PWV measured with both devices. The correlation coefficient for PWV measured with the two devices was 0.92 ( p < 0.0001). Compared with the Complior device, the Philips prototype slightly overestimated PWV by 0.24 (± 2 standard deviations, ± 1.91) m/s, especially when PWV was high. The correlation coefficient between the difference and the average of the Philips and Complior measurements was 0.21 ( p = 0.035). Nonetheless, they had similar determinants. Age, mean arterial pressure, and sex altogether explained 81.6 and 83.9% of the variance of PWV values measured with the Philips prototype and Complior device, respectively. When the two extremes of the three PWV values measured with the Philips prototype and the Complior device were investigated, the coefficients of variation were 8.26 and 3.26%, respectively. Compared with the Complior device, the Philips prototype had similar accuracy, determinants, and reproducibility in measuring PWV.

Reliability Testing of NASA Piezocomposite Actuators

NASA Technical Reports Server (NTRS)

Wilkie, W.; High, J.; Bockman, J.

2002-01-01

NASA Langley Research Center has developed a low-cost piezocomposite actuator which has application for controlling vibrations in large inflatable smart space structures, space telescopes, and high performance aircraft. Tests show the NASA piezocomposite device is capable of producing large, directional, in-plane strains on the order of 2000 parts-per-million peak-to-peak, with no reduction in free-strain performance to 100 million electrical cycles. This paper describes methods, measurements, and preliminary results from our reliability evaluation of the device under externally applied mechanical loads and at various operational temperatures. Tests performed to date show no net reductions in actuation amplitude while the device was moderately loaded through 10 million electrical cycles. Tests were performed at both room temperature and at the maximum operational temperature of the epoxy resin system used in manufacture of the device. Initial indications are that actuator reliability is excellent, with no actuator failures or large net reduction in actuator performance.

Analysis of a digital RF memory in a signal-delay application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jelinek, D.A.

1992-03-01

Laboratory simulation of the approach of a radar fuze towards a target is an important factor in our ability to accurately measure the radar's performance. This simulation is achieved, in part, by dynamically delaying and attenuating the radar's transmitted pulse and sending the result back to the radar's receiver. Historically, the device used to perform the dynamic delay has been a limiting factor in the evaluation of a radar's performance and characteristics. A new device has been proposed that appears to have more capability than previous dynamic delay devices. This device is the digital RF memory. This report presents themore » results of an analysis of a digital RF memory used in a signal-delay application. 2 refs.« less

PROSPECTIVE EVALUATION OF VISUAL ACUITY AGREEMENT BETWEEN STANDARD EARLY TREATMENT DIABETIC RETINOPATHY STUDY CHART AND A HANDHELD EQUIVALENT IN EYES WITH RETINAL PATHOLOGY.

PubMed

Rahimy, Ehsan; Reddy, Sahitya; DeCroos, Francis Char; Khan, M Ali; Boyer, David S; Gupta, Omesh P; Regillo, Carl D; Haller, Julia A

2015-08-01

To evaluate the visual acuity agreement between a standard back-illuminated Early Treatment Diabetic Retinopathy Study (ETDRS) chart and a handheld internally illuminated ETDRS chart. Two-center prospective study. Seventy patients (134 eyes) with retinal pathology were enrolled between October 2012 and August 2013. Visual acuity was measured using both the ETDRS chart and the handheld device by masked independent examiners after best protocol refraction. Examination was performed in the same room under identical illumination and testing conditions. The mean number of letters seen was 63.0 (standard deviation: 19.8 letters) and 61.2 letters (standard deviation: 19.1 letters) for the ETDRS chart and handheld device, respectively. Mean difference per eye between the ETDRS and handheld device was 1.8 letters. A correlation coefficient (r) of 0.95 demonstrated a positive linear correlation between ETDRS chart and handheld device measured acuities. Intraclass correlation coefficient was performed to assess the reproducibility of the measurements made by different observers measuring the same quantity and was calculated to be 0.95 (95% confidence interval: 0.93-0.96). Agreement was independent of retinal disease. The strong correlation between measured visual acuity using the ETDRS and handheld equivalent suggests that they may be used interchangeably, with accurate measurements. Potential benefits of this device include convenience and portability, as well as the ability to assess ETDRS visual acuity without a dedicated testing lane.

Comparison of anterior segment parameters and axial length measurements performed on a Scheimpflug device with biometry function and a reference optical biometer.

PubMed

Muzyka-Woźniak, Maria; Oleszko, Adam

2018-04-26

To compare measurements of axial length (AL), corneal curvature (K), anterior chamber depth (ACD) and white-to-white (WTW) distance on a new device combining Scheimpflug camera and partial coherence interferometry (Pentacam AXL) with a reference optical biometer (IOL Master 500). To evaluate differences between IOL power calculations based on the two biometers. Ninety-seven eyes of 97 consecutive cataract or refractive lens exchange patients were examined preoperatively on IOL Master 500 and Pentacam AXL units. Comparisons between two devices were performed for AL, K, ACD and WTW. Intraocular lens (IOL) power targeting emmetropia was calculated with SRK/T and Haigis formulas on both devices and compared. There were statistically significant differences between two devices for all measured parameters (P < 0.05), except ACD (P = 0.36). Corneal curvature measured with Pentacam AXL was significantly flatter then with IOL Master. The mean difference in AL was clinically insignificant (0.01 mm; 95% LoA 0.16 mm). Pentacam AXL yielded higher IOL power in 75% of eyes for Haigis formula and in 62% of eyes for SRK/T formula, with a mean difference within ± 0.5 D for 72 and 86% of eyes, respectively. There were statistically significant differences between AL, K and WTW measurements obtained with the compared biometers. Flatter corneal curvature measurements on Pentacam AXL necessitate formulas optimisation for Pentacam AXL.

Fabrication and Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

NASA Technical Reports Server (NTRS)

Chervenak, James A.; Adams, James S.; Bandler, Simon R.; Busch, Sara E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, Jan-Patrick;

Polymer taper bridge for silicon waveguide to single mode waveguide coupling

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Middlebrook, Christopher T.

2016-03-01

Coupling of optical power from high-density silicon waveguides to silica optical fibers for signal routing can incur high losses and often requires complex end-face preparation/processing. Novel coupling device taper structures are proposed for low coupling loss between silicon photonic waveguides and single mode fibers are proposed and devices are fabricated and measured in terms of performance. Theoretical mode conversion models for waveguide tapers are derived for optimal device structure design and performance. Commercially viable vertical and multi-layer taper designs using polymer waveguide materials are proposed as innovative, cost-efficient, and mass-manufacturable optical coupling devices. The coupling efficiency for both designs is determined to evaluate optimal device dimensions and alignment tolerances with both silicon rib waveguides and silicon nanowire waveguides. Propagation loss as a function of waveguide roughness and metallic loss are determined and correlated to waveguide dimensions to obtain total insertion loss for the proposed taper designs. Multi-layer tapers on gold-sputtered substrates are fabricated through photolithography as proof-of-concept devices and evaluated for device loss optimization. Tapered waveguide coupling loss with Si WGs (2.74 dB) was experimentally measured with high correlation to theoretical results.

Medical Device for Automated Prick Test Reading.

PubMed

Justo, Xabier; Diaz, Inaki; Gil, Jorge Juan; Gastaminza, Gabriel

2018-05-01

Allergy tests are routinely performed in most hospitals everyday. However, measuring the outcomes of these tests is still a very laborious manual task. Current methods and systems lack of precision and repeatability. This paper presents a novel mechatronic system that is able to scan a patient's entire arm and provide allergists with precise measures of wheals for diagnosis. The device is based on 3-D laser technology and specific algorithms have been developed to process the information gathered. This system aims to automate the reading of skin prick tests and make gains in speed, accuracy, and reliability. Several experiments have been performed to evaluate the performance of the system.

Influence of intrinsic noise generated by a thermotesting device on thermal sensory detection and thermal pain detection thresholds.

PubMed

Pavlaković, G; Züchner, K; Zapf, A; Bachmann, C G; Graf, B M; Crozier, T A; Pavlaković, H

2009-08-01

Various factors can influence thermal perception threshold measurements and contribute significantly to unwanted variability of the tests. To minimize this variability, testing should be performed under strictly controlled conditions. Identifying the factors that increase the variability and eliminating their influence should increase reliability and reproducibility. Currently available thermotesting devices use a water-cooling system that generates a continuous noise of approximately 60 dB. In order to analyze whether this noise could influence the thermal threshold measurements we compared the thresholds obtained with a silent thermotesting device to those obtained with a commercially available device. The subjects were tested with one randomly chosen device on 1 day and with the other device 7 days later. At each session, heat, heat pain, cold, and cold pain thresholds were determined with three measurements. Bland-Altman analysis was used to assess agreement in measurements obtained with different devices and it was shown that the intersubject variability of the thresholds obtained with the two devices was comparable for all four thresholds tested. In contrast, the intrasubject variability of the thresholds for heat, heat pain, and cold pain detection was significantly lower with the silent device. Our results show that thermal sensory thresholds measured with the two devices are comparable. However, our data suggest that, for studies with repeated measurements on the same subjects, a silent thermotesting device may allow detection of smaller differences in the treatment effects and/or may permit the use of a smaller number of tested subjects. Muscle Nerve 40: 257-263, 2009.

Performing mathematics activities with non-standard units of measurement using robots controlled via speech-generating devices: three case studies.

PubMed

Adams, Kim D; Cook, Albert M

2017-07-01

Purpose To examine how using a Lego robot controlled via a speech-generating device (SGD) can contribute to how students with physical and communication impairments perform hands-on and communicative mathematics measurement activities. This study was a follow-up to a previous study. Method Three students with cerebral palsy used the robot to measure objects using non-standard units, such as straws, and then compared and ordered the objects using the resulting measurement. Their performance was assessed, and the manipulation and communication events were observed. Teachers and education assistants were interviewed regarding robot use. Results Similar benefits to the previous study were found in this study. Gaps in student procedural knowledge were identified such as knowing to place measurement units tip-to-tip, and students' reporting revealed gaps in conceptual understanding. However, performance improved with repeated practice. Stakeholders identified that some robot tasks took too long or were too difficult to perform. Conclusions Having access to both their SGD and a robot gave the students multiple ways to show their understanding of the measurement concepts. Though they could participate actively in the new mathematics activities, robot use is most appropriate in short tasks requiring reasonable operational skill. Implications for Rehabilitation Lego robots controlled via speech-generating devices (SGDs) can help students to engage in the mathematics pedagogy of performing hands-on activities while communicating about concepts. Students can "show what they know" using the Lego robots, and report and reflect on concepts using the SGD. Level 1 and Level 2 mathematics measurement activities have been adapted to be accomplished by the Lego robot. Other activities can likely be accomplished with similar robot adaptations (e.g., gripper, pen). It is not recommended to use the robot to measure items that are long, or perform measurements that require high operational competence in order to be successful.

Micromachined structures for vertical microelectrooptical devices on InP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seassal, C.; Leclercq, J.L.; Letartre, X.

1996-12-31

The authors presented a microstructuring method in order to fabricate tunable vertical resonant cavity optical devices. PL characterizations were performed on a test structure in order to evaluate the effect of the cavity thickness on the peak characteristics. Modeling of the mechanical, electrostatic, and optical behavior of the device, PL simulation were performed, and showed a good agreement with the experiments. This is a first preliminary validation of InP-based MOEMS for further realization of tunable wavelength-selective passive filters, or photodiodes and lasers by incorporating active region within the cavity. Micro-reflectivity measurements with a spatial resolution of 20 {micro}m are underwaymore » in their group, in order to measure directly the resonance shift and spectral linewidth.« less

Advanced analytical modeling of double-gate Tunnel-FETs - A performance evaluation

NASA Astrophysics Data System (ADS)

Graef, Michael; Hosenfeld, Fabian; Horst, Fabian; Farokhnejad, Atieh; Hain, Franziska; Iñíguez, Benjamín; Kloes, Alexander

2018-03-01

The Tunnel-FET is one of the most promising devices to be the successor of the standard MOSFET due to its alternative current transport mechanism, which allows a smaller subthreshold slope than the physically limited 60 mV/dec of the MOSFET. Recently fabricated devices show smaller slopes already but mostly not over multiple decades of the current transfer characteristics. In this paper the performance limiting effects, occurring during the fabrication process of the device, such as doping profiles and midgap traps are analyzed by physics-based analytical models and their performance limiting abilities are determined. Additionally, performance enhancing possibilities, such as hetero-structures and ambipolarity improvements are introduced and discussed. An extensive double-gate n-Tunnel-FET model is presented, which meets the versatile device requirements and shows a good fit with TCAD simulations and measurement data.

Interplay between Interfacial Structures and Device Performance in Organic Solar Cells: A Case Study with the Low Work Function Metal, Calcium.

PubMed

Ju, Huanxin; Knesting, Kristina M; Zhang, Wei; Pan, Xiao; Wang, Chia-Hsin; Yang, Yaw-Wen; Ginger, David S; Zhu, Junfa

2016-01-27

A better understanding of how interfacial structure affects charge carrier recombination would benefit the development of highly efficient organic photovoltaic (OPV) devices. In this paper, transient photovoltage (TPV) and charge extraction (CE) measurements are used in combination with synchrotron radiation photoemission spectroscopy (SRPES) to gain insight into the correlation between interfacial properties and device performance. OPV devices based on PCDTBT/PC71BM with a Ca interlayer were studied as a reference system to investigate the interfacial effects on device performance. Devices with a Ca interlayer exhibit a lower recombination than devices with only an Al cathode at a given charge carrier density (n). In addition, the interfacial band structures indicate that the strong dipole moment produced by the Ca interlayer can facilitate the extraction of electrons and drive holes away from the cathode/polymer interface, resulting in beneficial reduction in interfacial recombination losses. These results help explain the higher efficiencies of devices made with Ca interlayers compared to that without the Ca interlayer.

Effects of Maintenance on Quality of Performance of Cryotherapy Devices for Treatment of Precancerous Cervical Lesions.

PubMed

Maza, Mauricio; Figueroa, Ruben; Laskow, Bari; Juárez, Alexa; Alfaro, Karla; Alonzo, Todd A; Felix, Juan C; Gage, Julia C; Cremer, Miriam

2018-01-01

The aim of the study was to evaluate the impact of maintenance on performance of cryosurgical equipment used in El Salvador primary health clinics. Nine gynecological cryotherapy devices used in El Salvador were bench tested against a new machine of the same make and model. The devices were run for five successive double-freeze cycles. The El Salvador machines then received maintenance by a specialized engineer and another double-freeze cycle was performed. Temperature at the device probe tip was recorded throughout each cycle and ballistic gelatin was used as the tissue analogue to measure freeze ball dimensions achieved by the devices. Outcome measures were mean lowest-sustained temperatures and freeze ball mean weight, depth, and diameter. Paired and unpaired t tests were used to compare results premaintenance versus postmaintenance and postmaintenance versus the reference, respectively. Premaintenance versus postmaintenance freeze ball dimensions were significantly different (mean differences in weight = 2.31 g, p = .01; depth = 2.29 mm, p = .03; diameter = 3.51 mm, p = .02). However, postmaintenance dimensions were not significantly different than those of the reference (weight = 7.44 g vs. 8.39 g, p = .07; depth = 10.71 vs. 11.24 mm, p = .1; diameter = 31.38 mm vs. 32.05 mm, p = .3). Postmaintenance, minimum, and lowest-sustained temperatures were within the recommended clinical range. Specialized maintenance was necessary for heavily used cryotherapy devices to perform adequately, highlighting the challenges of gas-based cryotherapy in low- and middle-income countries.

Experimental measurement-device-independent verification of quantum steering

NASA Astrophysics Data System (ADS)

Kocsis, Sacha; Hall, Michael J. W.; Bennet, Adam J.; Saunders, Dylan J.; Pryde, Geoff J.

2015-01-01

Bell non-locality between distant quantum systems—that is, joint correlations which violate a Bell inequality—can be verified without trusting the measurement devices used, nor those performing the measurements. This leads to unconditionally secure protocols for quantum information tasks such as cryptographic key distribution. However, complete verification of Bell non-locality requires high detection efficiencies, and is not robust to typical transmission losses over long distances. In contrast, quantum or Einstein-Podolsky-Rosen steering, a weaker form of quantum correlation, can be verified for arbitrarily low detection efficiencies and high losses. The cost is that current steering-verification protocols require complete trust in one of the measurement devices and its operator, allowing only one-sided secure key distribution. Here we present measurement-device-independent steering protocols that remove this need for trust, even when Bell non-locality is not present. We experimentally demonstrate this principle for singlet states and states that do not violate a Bell inequality.

Experimental measurement-device-independent verification of quantum steering.

PubMed

Kocsis, Sacha; Hall, Michael J W; Bennet, Adam J; Saunders, Dylan J; Pryde, Geoff J

2015-01-07

Bell non-locality between distant quantum systems--that is, joint correlations which violate a Bell inequality--can be verified without trusting the measurement devices used, nor those performing the measurements. This leads to unconditionally secure protocols for quantum information tasks such as cryptographic key distribution. However, complete verification of Bell non-locality requires high detection efficiencies, and is not robust to typical transmission losses over long distances. In contrast, quantum or Einstein-Podolsky-Rosen steering, a weaker form of quantum correlation, can be verified for arbitrarily low detection efficiencies and high losses. The cost is that current steering-verification protocols require complete trust in one of the measurement devices and its operator, allowing only one-sided secure key distribution. Here we present measurement-device-independent steering protocols that remove this need for trust, even when Bell non-locality is not present. We experimentally demonstrate this principle for singlet states and states that do not violate a Bell inequality.

Attenuation length measurements of a liquid scintillator with LabVIEW and reliability evaluation of the device

NASA Astrophysics Data System (ADS)

Gao, Long; Yu, Bo-Xiang; Ding, Ya-Yun; Zhou, Li; Wen, Liang-Jian; Xie, Yu-Guang; Wang, Zhi-Gang; Cai, Xiao; Sun, Xi-Lei; Fang, Jian; Xue, Zhen; Zhang, Ai-Wu; Lü, Qi-Wen; Sun, Li-Jun; Ge, Yong-Shuai; Liu, Ying-Biao; Niu, Shun-Li; Hu, Tao; Cao, Jun; Lü, Jun-Guang

2013-07-01

An attenuation length measurement device was constructed using an oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested in a variety of ways. The test results show that the set-up has a good stability and high precision (sigma/mean reached 0.4 percent). Besides, the accuracy of the measurement system will decrease by about 17 percent if a filter is used. The attenuation length of a gadolinium-loaded liquid scintillator (Gd-LS) was measured as 15.10±0.35 m where Gd-LS was heavily used in the Daya Bay Neutrino Experiment. In addition, one method based on the Beer-Lambert law was proposed to investigate the reliability of the measurement device, the R-square reached 0.9995. Moreover, three purification methods for Linear Alkyl Benzene (LAB) production were compared in the experiment.

Performance testing of supercapacitors: Important issues and uncertainties

NASA Astrophysics Data System (ADS)

Zhao, Jingyuan; Gao, Yinghan; Burke, Andrew F.

2017-09-01

Supercapacitors are a promising technology for high power energy storage, which have been used in some industrial and vehicles applications. Hence, it is important that information concerning the performance of supercapacitors be detailed and reliable so system designers can make rational decisions regarding the selection of the energy storage components. This paper is concerned with important issues and uncertainties regarding the performance testing of supercapacitors. The effect of different test procedures on the measured characteristics of both commercial and prototype supercapacitors including hybrid supercapacitors have been studied. It was found that the test procedure has a relatively minor effect on the capacitance of carbon/carbon devices and a more significant effect on the capacitance of hybrid supercapacitors. The device characteristic with the greatest uncertainty is the resistance and subsequently the claimed power capability of the device. The energy density should be measured by performing constant power discharges between appropriate voltage limits. This is particularly important in the case of hybrid supercapacitors for which the energy density is rate dependent and the simple relationship E = ½CV2 does not yield accurate estimates of the energy stored. In general, most of the important issues for testing carbon/carbon devices become more serious for hybrid supercapacitors.

Performance of cardiopulmonary resuscitation feedback systems in a long-distance train with distributed traction.

PubMed

González-Otero, Digna M; de Gauna, Sofía Ruiz; Ruiz, Jesus; Rivero, Raquel; Gutierrez, J J; Saiz, Purificación; Russell, James K

2018-04-20

Out-of-hospital cardiac arrest is common in public locations, including public transportation sites. Feedback devices are increasingly being used to improve chest-compression quality. However, their performance during public transportation has not been studied yet. To test two CPR feedback devices representative of the current technologies (accelerometer and electromag- netic-field) in a long-distance train. Volunteers applied compressions on a manikin during the train route using both feedback devices. Depth and rate measurements computed by the devices were compared to the gold-standard values. Sixty-four 4-min records were acquired. The accelerometer-based device provided visual help in all experiments. Median absolute errors in depth and rate were 2.4 mm and 1.3 compressions per minute (cpm) during conventional speed, and 2.5 mm and 1.2 cpm during high speed. The electromagnetic-field-based device never provided CPR feedback; alert messages were shown instead. However, measurements were stored in its internal memory. Absolute errors for depth and rate were 2.6 mm and 0.7 cpm during conventional speed, and 2.6 mm and 0.7 cpm during high speed. Both devices were accurate despite the accelerations and the electromagnetic interferences induced by the train. However, the electromagnetic-field-based device would require modifications to avoid excessive alerts impeding feedback.

On-sky performance evaluation and calibration of a polarization-sensitive focal plane array

NASA Astrophysics Data System (ADS)

Vorobiev, Dmitry; Ninkov, Zoran; Brock, Neal; West, Ray

2016-07-01

The advent of pixelated micropolarizer arrays (MPAs) has facilitated the development of polarization-sensitive focal plane arrays (FPAs) based on charge-coupled devices (CCDs) and active pixel sensors (APSs), which are otherwise only able to measure the intensity of light. Polarization sensors based on MPAs are extremely compact, light-weight, mechanically robust devices with no moving parts, capable of measuring the degree and angle of polarization of light in a single snapshot. Furthermore, micropolarizer arrays based on wire grid polarizers (so called micro-grid polarizers) offer extremely broadband performance, across the optical and infrared regimes. These devices have potential for a wide array of commercial and research applications, where measurements of polarization can provide critical information, but where conventional polarimeters could be practically implemented. To date, the most successful commercial applications of these devices are 4D Technology's PhaseCam laser interferometers and PolarCam imaging polarimeters. Recently, MPA-based polarimeters have been identified as a potential solution for space-based telescopes, where the small size, snapshot capability and low power consumption (offered by these devices) are extremely desirable. In this work, we investigated the performance of MPA-based polarimeters designed for astronomical polarimetry using the Rochester Institute of Technology Polarization Imaging Camera (RITPIC). We deployed RITPIC on the 0.9 meter SMARTS telescope at the Cerro Tololo Inter-American Observatory and observed a variety of astronomical objects (calibration stars, variable stars, reflection nebulae and planetary nebulae). We use our observations to develop calibration procedures that are unique to these devices and provide an estimate for polarimetric precision that is achievable.

When to Perform Antenna Measurements in a Near-Field Range or a Short Tapered Chamber

DTIC Science & Technology

2017-03-01

study was undertaken to quantify and compare electromagnetic device (i.e., antenna) measurements using the US Army Research Laboratory’s (ARL’s) near...results for future antennas under test in the most cost-effective manner (man-hours, custom mount, etc.) 15. SUBJECT TERMS electromagnetic , chamber...study was undertaken to quantify and compare electromagnetic (EM) device (i.e., antenna) measurements using the US Army Research Laboratory’s (ARL

Evaluating the Validity of Current Mainstream Wearable Devices in Fitness Tracking Under Various Physical Activities: Comparative Study

PubMed Central

Xie, Junqing; Wen, Dong; Liang, Lizhong; Jia, Yuxi; Gao, Li

2018-01-01

Background Wearable devices have attracted much attention from the market in recent years for their fitness monitoring and other health-related metrics; however, the accuracy of fitness tracking results still plays a major role in health promotion. Objective The aim of this study was to evaluate the accuracy of a host of latest wearable devices in measuring fitness-related indicators under various seminatural activities. Methods A total of 44 healthy subjects were recruited, and each subject was asked to simultaneously wear 6 devices (Apple Watch 2, Samsung Gear S3, Jawbone Up3, Fitbit Surge, Huawei Talk Band B3, and Xiaomi Mi Band 2) and 2 smartphone apps (Dongdong and Ledongli) to measure five major health indicators (heart rate, number of steps, distance, energy consumption, and sleep duration) under various activity states (resting, walking, running, cycling, and sleeping), which were then compared with the gold standard (manual measurements of the heart rate, number of steps, distance, and sleep, and energy consumption through oxygen consumption) and calculated to determine their respective mean absolute percentage errors (MAPEs). Results Wearable devices had a rather high measurement accuracy with respect to heart rate, number of steps, distance, and sleep duration, with a MAPE of approximately 0.10, whereas poor measurement accuracy was observed for energy consumption (calories), indicated by a MAPE of up to 0.44. The measurements varied for the same indicator measured by different fitness trackers. The variation in measurement of the number of steps was the highest (Apple Watch 2: 0.42; Dongdong: 0.01), whereas it was the lowest for heart rate (Samsung Gear S3: 0.34; Xiaomi Mi Band 2: 0.12). Measurements differed insignificantly for the same indicator measured under different states of activity; the MAPE of distance and energy measurements were in the range of 0.08 to 0.17 and 0.41 to 0.48, respectively. Overall, the Samsung Gear S3 performed the best for the measurement of heart rate under the resting state (MAPE of 0.04), whereas Dongdong performed the best for the measurement of the number of steps under the walking state (MAPE of 0.01). Fitbit Surge performed the best for distance measurement under the cycling state (MAPE of 0.04), and Huawei Talk Band B3 performed the best for energy consumption measurement under the walking state (MAPE of 0.17). Conclusions At present, mainstream devices are able to reliably measure heart rate, number of steps, distance, and sleep duration, which can be used as effective health evaluation indicators, but the measurement accuracy of energy consumption is still inadequate. Fitness trackers of different brands vary with regard to measurement of indicators and are all affected by the activity state, which indicates that manufacturers of fitness trackers need to improve their algorithms for different activity states. PMID:29650506

Direct-current polarization characteristics of various AlGaAs laser diodes

NASA Technical Reports Server (NTRS)

Fuhr, P. L.

1984-01-01

Polarization characteristics of AlGaAs laser diodes having various device geometries have been measured. Measurements were performed with the laser diodes operating under dc conditions. Results show that laser diodes having different device geometries have optical outputs that exhibit varying degrees of polarization purity. Implications of this result, with respect to incoherent polarization-beam combining, are addressed.

Measurements relevant to the performance of infrared opto-electronic devices in fog

NASA Astrophysics Data System (ADS)

Clay, M. R.; Lenham, A. P.

1981-04-01

The transmissivity of the atmosphere in the visible and infrared was measured in a number of fogs. The data is summarized in the form of tables and diagrams that indicate the gain in range that may be achievable in the various infrared windows. In some fogs there does not appear to be any significant advantage in using infrared devices.

Laser spectroscopy for totally non-intrusive detection of oxygen in modified atmosphere food packages

NASA Astrophysics Data System (ADS)

Cocola, L.; Fedel, M.; Poletto, L.; Tondello, G.

2015-04-01

A device for measuring the oxygen concentration inside packages in modified atmosphere working in a completely non-intrusive way has been developed and tested. The device uses tunable diode laser spectroscopy in a geometry similar to a short distance LIDAR: A laser beam is sent through the top film of a food package, and the absorption is measured by detecting the light scattered by the bottom of the container or by a portion of the food herein contained. The device can operate completely in a contactless way from the package, and the distances of absorption both outside and inside the package are measured with a triangulation system. The performances of the device have been tested for various types of containers, and absolute values for the oxygen concentration have been compared with standard albeit destructive measurements.

Validation of two automatic devices for self-measurement of blood pressure according to the International Protocol of the European Society of Hypertension: the Omron M6 (HEM-7001-E) and the Omron R7 (HEM 637-IT).

PubMed

Topouchian, Jirar A; El Assaad, Mohamed A; Orobinskaia, Ludmila V; El Feghali, Ramzi N; Asmar, Roland G

2006-06-01

Two electronic devices for self-measurement of blood pressure - a brachial monitor, the Omron M6, and a wrist monitor, the Omron R7 - were evaluated in two separate studies according to the International Protocol of the European Society of Hypertension. The International Validation Protocol is divided into two phases: the first phase is performed on 15 selected participants (45 pairs of blood pressure measurements); if the device passes this phase, 18 supplementary participants are included (54 pairs of blood pressure measurements) making a total number of 33 participants (99 pairs of blood pressure measurements) on whom the final validation is performed. The same methodology recommended by the European Society of Hypertension protocol was applied for both studies. In each study and for each participant, four blood pressure measurements were taken simultaneously by two trained observers using mercury sphygmomanometers alternately with three measurements taken by the tested device. The difference between the blood pressure value given by the device and that obtained by the two observers (mean of the two observers) was calculated for each measure. The 99 pairs of blood pressure differences were classified into three categories (

In vivo skin imaging for hydration and micro relief-measurement.

PubMed

Kardosova, Z; Hegyi, V

2013-01-01

We present the results of our work with device used for measurement of skin capacitance before and after application of moisturizing creams and results of experiment performed on cellulose filter papers soaked with different solvents. The measurements were performed by a device built on capacitance sensor, which provides an investigator with a capacitance image of the skin. The capacitance values are coded in a range of 256 gray levels then the skin hydration can be characterized using parameters derived from gray level histogram by specific software. The images obtained by device allow a highly precise observation of skin topography. Measuring of skin capacitance brings new, objective, reliable information about topographical, physical and chemical parameters of the skin. The study shows that there is a good correlation between the average grayscale values and skin hydration. In future works we need to complete more comparison studies, interpret the average grayscale values to skin hydration levels and use it for follow-up of dynamics of skin micro-relief and hydration changes (Fig. 6, Ref. 15).

Application of Mixed Effects Limits of Agreement in the Presence of Multiple Sources of Variability: Exemplar from the Comparison of Several Devices to Measure Respiratory Rate in COPD Patients

PubMed Central

Weir, Christopher J.; Rubio, Noah; Rabinovich, Roberto; Pinnock, Hilary; Hanley, Janet; McCloughan, Lucy; Drost, Ellen M.; Mantoani, Leandro C.; MacNee, William; McKinstry, Brian

2016-01-01

Introduction The Bland-Altman limits of agreement method is widely used to assess how well the measurements produced by two raters, devices or systems agree with each other. However, mixed effects versions of the method which take into account multiple sources of variability are less well described in the literature. We address the practical challenges of applying mixed effects limits of agreement to the comparison of several devices to measure respiratory rate in patients with chronic obstructive pulmonary disease (COPD). Methods Respiratory rate was measured in 21 people with a range of severity of COPD. Participants were asked to perform eleven different activities representative of daily life during a laboratory-based standardised protocol of 57 minutes. A mixed effects limits of agreement method was used to assess the agreement of five commercially available monitors (Camera, Photoplethysmography (PPG), Impedance, Accelerometer, and Chest-band) with the current gold standard device for measuring respiratory rate. Results Results produced using mixed effects limits of agreement were compared to results from a fixed effects method based on analysis of variance (ANOVA) and were found to be similar. The Accelerometer and Chest-band devices produced the narrowest limits of agreement (-8.63 to 4.27 and -9.99 to 6.80 respectively) with mean bias -2.18 and -1.60 breaths per minute. These devices also had the lowest within-participant and overall standard deviations (3.23 and 3.29 for Accelerometer and 4.17 and 4.28 for Chest-band respectively). Conclusions The mixed effects limits of agreement analysis enabled us to answer the question of which devices showed the strongest agreement with the gold standard device with respect to measuring respiratory rates. In particular, the estimated within-participant and overall standard deviations of the differences, which are easily obtainable from the mixed effects model results, gave a clear indication that the Accelerometer and Chest-band devices performed best. PMID:27973556

A quality assurance device for measuring afterloader performance and transit dose for nasobiliary high-dose-rate brachytherapy.

PubMed

Deufel, Christopher L; Mullins, John P; Zakhary, Mark J

2018-05-17

Nasobiliary high-dose-rate (HDR) brachytherapy has emerged as an effective tool to boost the radiation dose for patients with unresectable perihilar cholangiocarcinoma. This work describes a quality assurance (QA) tool for measuring the HDR afterloader's performance, including the transit dose, when the source wire travels through a tortuous nasobiliary catheter path. The nasobiliary QA device was designed to mimic the anatomical path of a nasobiliary catheter, including the nasal, stomach, duodenum, and bile duct loops. Two of these loops, the duodenum and bile duct loops, have adjustable radii of curvature, resulting in the ability to maximize stress on the source wire in transit. The device was used to measure the performance over time for the HDR afterloader and the differences between intraluminal catheter lots. An upper limit on the transit dose was also measured using radiochromic film and compared with a simple theoretical model. The QA device was capable of detecting performance variations among nasobiliary catheter lots and following radioactive source replacement. The transit dose from a nasobiliary treatment increased by up to one order of magnitude when the source wire encountered higher than normal friction. Three distinct travel speeds of the source wire were observed: 5.2, 17.4, and 54.7 cm/s. The maximum transit dose was 0.3 Gy at a radial distance of 5 mm from a 40.3 kU 192 Ir source. The source wire encounters substantially greater friction when it navigates through the nasobiliary brachytherapy catheter. A QA tool that mimics the nasal, stomach, duodenum, and bile duct loops may be used to evaluate transit dose and the afterloader's performance over time. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Large-scale performance evaluation of Accu-Chek inform II point-of-care glucose meters.

PubMed

Jeong, Tae-Dong; Cho, Eun-Jung; Ko, Dae-Hyun; Lee, Woochang; Chun, Sail; Hong, Ki-Sook; Min, Won-Ki

2016-12-01

The aim of this study was to report the experience of large-scale performance evaluation of 238 Accu-Chek Inform II point-of-care (POC) glucose meters in a single medical setting. The repeatability of 238 POC devices, the within-site imprecision of 12 devices, and the linearity of 49 devices were evaluated using glucose control solutions. The glucose results of 24 POC devices and central laboratory were compared using patient samples. Mean concentration of control solutions was 2.39 mmol/L for Level 1 and 16.52 mmol/L for Level 2. The pooled repeatability coefficient of variation (CV) of the 238 devices was 2.0% for Level 1 and 1.6% for Level 2. The pooled within-site imprecision CV and reproducibility CV of the 12 devices were 2.7% and 2.7% for Level 1, and 1.9%, and 1.9% for Level 2, respectively. The test results of all 49 devices were linear within analytical measurement range from 1.55-31.02 mmol/L. The correlation coefficient for individual POC devices ranged from 0.9967-0.9985. The total correlation coefficient for the 24 devices was 0.998. The Accu-Chek Inform II POC blood glucose meters performed well in terms of precision, linearity, and correlation evaluations. Consensus guidelines for the large-scale performance evaluations of POC devices are required.

Measures of rowing performance.

PubMed

Smith, T Brett; Hopkins, Will G

2012-04-01

Accurate measures of performance are important for assessing competitive athletes in practi~al and research settings. We present here a review of rowing performance measures, focusing on the errors in these measures and the implications for testing rowers. The yardstick for assessing error in a performance measure is the random variation (typical or standard error of measurement) in an elite athlete's competitive performance from race to race: ∼1.0% for time in 2000 m rowing events. There has been little research interest in on-water time trials for assessing rowing performance, owing to logistic difficulties and environmental perturbations in performance time with such tests. Mobile ergometry via instrumented oars or rowlocks should reduce these problems, but the associated errors have not yet been reported. Measurement of boat speed to monitor on-water training performance is common; one device based on global positioning system (GPS) technology contributes negligible extra random error (0.2%) in speed measured over 2000 m, but extra error is substantial (1-10%) with other GPS devices or with an impeller, especially over shorter distances. The problems with on-water testing have led to widespread use of the Concept II rowing ergometer. The standard error of the estimate of on-water 2000 m time predicted by 2000 m ergometer performance was 2.6% and 7.2% in two studies, reflecting different effects of skill, body mass and environment in on-water versus ergometer performance. However, well trained rowers have a typical error in performance time of only ∼0.5% between repeated 2000 m time trials on this ergometer, so such trials are suitable for tracking changes in physiological performance and factors affecting it. Many researchers have used the 2000 m ergometer performance time as a criterion to identify other predictors of rowing performance. Standard errors of the estimate vary widely between studies even for the same predictor, but the lowest errors (~1-2%) have been observed for peak power output in an incremental test, some measures of lactate threshold and measures of 30-second all-out power. Some of these measures also have typical error between repeated tests suitably low for tracking changes. Combining measures via multiple linear regression needs further investigation. In summary, measurement of boat speed, especially with a good GPS device, has adequate precision for monitoring training performance, but adjustment for environmental effects needs to be investigated. Time trials on the Concept II ergometer provide accurate estimates of a rower's physiological ability to output power, and some submaximal and brief maximal ergometer performance measures can be used frequently to monitor changes in this ability. On-water performance measured via instrumented skiffs that determine individual power output may eventually surpass measures derived from the Concept II.

Comparative performance assessment of point-of-care testing devices for measuring glucose and ketones at the patient bedside.

PubMed

Ceriotti, Ferruccio; Kaczmarek, Ewa; Guerra, Elena; Mastrantonio, Fabrizio; Lucarelli, Fausto; Valgimigli, Francesco; Mosca, Andrea

2015-03-01

Point-of-care (POC) testing devices for monitoring glucose and ketones can play a key role in the management of dysglycemia in hospitalized diabetes patients. The accuracy of glucose devices can be influenced by biochemical changes that commonly occur in critically ill hospital patients and by the medication prescribed. Little is known about the influence of these factors on ketone POC measurements. The aim of this study was to assess the analytical performance of POC hospital whole-blood glucose and ketone meters and the extent of glucose interference factors on the design and accuracy of ketone results. StatStrip glucose/ketone, Optium FreeStyle glucose/ketone, and Accu-Chek Performa glucose were also assessed and results compared to a central laboratory reference method. The analytical evaluation was performed according to Clinical and Laboratory Standards Institute (CLSI) protocols for precision, linearity, method comparison, and interference. The interferences assessed included acetoacetate, acetaminophen, ascorbic acid, galactose, maltose, uric acid, and sodium. The accuracies of both Optium ketone and glucose measurements were significantly influenced by varying levels of hematocrit and ascorbic acid. StatStrip ketone and glucose measurements were unaffected by the interferences tested with exception of ascorbic acid, which reduced the higher level ketone value. The accuracy of Accu-Chek glucose measurements was affected by hematocrit, by ascorbic acid, and significantly by galactose. The method correlation assessment indicated differences between the meters in compliance to ISO 15197 and CLSI 12-A3 performance criteria. Combined POC glucose/ketone methods are now available. The use of these devices in a hospital setting requires careful consideration with regard to the selection of instruments not sensitive to hematocrit variation and presence of interfering substances. © 2014 Diabetes Technology Society.

Issues in vibration energy harvesting

NASA Astrophysics Data System (ADS)

Zhang, Hui; Corr, Lawrence R.; Ma, Tianwei

2018-05-01

In this study, fundamental issues related to bandwidth and nonlinear resonance in vibrational energy harvesting devices are investigated. The results show that using bandwidth as a criterion to measure device performance can be misleading. For a linear device, an enlarged bandwidth is achieved at the cost of sacrificing device performance near resonance, and thus widening the bandwidth may offer benefits only when the natural frequency of the linear device cannot match the dominant excitation frequency. For a nonlinear device, since the principle of superposition does not apply, the ''broadband" performance improvements achieved for single-frequency excitations may not be achievable for multi-frequency excitations. It is also shown that a large-amplitude response based on the traditional ''nonlinear resonance" does not always result in the optimal performance for a nonlinear device because of the negative work done by the excitation, which indicates energy is returned back to the excitation. Such undesired negative work is eliminated at global resonance, a generalized resonant condition for both linear and nonlinear systems. While the linear resonance is a special case of global resonance for a single-frequency excitation, the maximum potential of nonlinear energy harvesting can be reached for multi-frequency excitations by using global resonance to simultaneously harvest energy distributed over multiple frequencies.

Design and performance of coded aperture optical elements for the CESR-TA x-ray beam size monitor

NASA Astrophysics Data System (ADS)

Alexander, J. P.; Chatterjee, A.; Conolly, C.; Edwards, E.; Ehrlichman, M. P.; Flanagan, J. W.; Fontes, E.; Heltsley, B. K.; Lyndaker, A.; Peterson, D. P.; Rider, N. T.; Rubin, D. L.; Seeley, R.; Shanks, J.

2014-12-01

We describe the design and performance of optical elements for an x-ray beam size monitor (xBSM), a device measuring e+ and e- beam sizes in the CESR-TA storage ring. The device can measure vertical beam sizes of 10 - 100 μm on a turn-by-turn, bunch-by-bunch basis at e± beam energies of 2 - 5 GeV. x-rays produced by a hard-bend magnet pass through a single- or multiple-slit (coded aperture) optical element onto a detector. The coded aperture slit pattern and thickness of masking material forming that pattern can both be tuned for optimal resolving power. We describe several such optical elements and show how well predictions of simple models track measured performances.

TIDBIT: portable diagnostics of multiplexed nutrition deficiencies: iron, vitamin A and inflammation status (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lu, Zhengda; Erickson, David

2017-03-01

Vitamin A and iron deficiency are common malnutrition affecting billions of people worldwide. However, in infrastructure limited settings, access to blood vitamin A and iron status test is limited because of the complexity and cost of traditional diagnostic methods. Direct measurements of vitamin A and iron level is not easy to perform, and it is necessary to measure approximate marker for obtaining vitamin A and iron deficiency status. Measurement of inflammatory marker is also necessary because the vitamin A and iron level are altered by inflammation status. Here we introduced a multiplex rapid point-of-care (POC) diagnostic devices that simultaneously characterize three markers relevant to vitamin A, iron and inflammation status: retinol binding protein 4, ferritin and C-reactive protein with lateral flow immunoassay test strips. Level of retinol binding protein 4, ferritin and C-reactive protein are indicated by excitation intensity of fluorescence tags with three different colors. The test can be done within 15 minutes and a complete sample-answer quantitative results of vitamin A, iron and inflammation status level can be obtained with assists of a smartphone and an external device. We also demonstrated the device is able to perform colorimetric analysis on single test area. which gives the device potential to perform more tests simultaneously at the same time.

Access to hands-on mathematics measurement activities using robots controlled via speech generating devices: three case studies.

PubMed

Adams, Kim; Cook, Al

2014-07-01

To examine how using a robot controlled via a speech generating device (SGD) influences the ways students with physical and communication limitations can demonstrate their knowledge in math measurement activities. Three children with severe physical disabilities and complex communication needs used the robot and SGD system to perform four math measurement lessons in comparing, sorting and ordering objects. The performance of the participants was measured and the process of using the system was described in terms of manipulation and communication events. Stakeholder opinions were solicited regarding robot use. Robot use revealed some gaps in the procedural knowledge of the participants. Access to both the robot and SGD was shown to provide several benefits. Stakeholders thought the intervention was important and feasible for a classroom environment. The participants were able to participate actively in the hands-on and communicative measurement activities and thus meet the demands of current math instruction methods. Current mathematics pedagogy encourages doing hands-on activities while communicating about concepts. Adapted Lego robots enabled children with severe physical disabilities to perform hands-on length measurement activities. Controlling the robots from speech generating devices (SGD) enabled the children, who also had complex communication needs, to reflect and report on results during the activities. By using the robots combined with SGDs, children both exhibited their knowledge of and experienced the concepts of mathematical measurements.

High-throughput microfluidic single-cell digital polymerase chain reaction.

PubMed

White, A K; Heyries, K A; Doolin, C; Vaninsberghe, M; Hansen, C L

2013-08-06

Here we present an integrated microfluidic device for the high-throughput digital polymerase chain reaction (dPCR) analysis of single cells. This device allows for the parallel processing of single cells and executes all steps of analysis, including cell capture, washing, lysis, reverse transcription, and dPCR analysis. The cDNA from each single cell is distributed into a dedicated dPCR array consisting of 1020 chambers, each having a volume of 25 pL, using surface-tension-based sample partitioning. The high density of this dPCR format (118,900 chambers/cm(2)) allows the analysis of 200 single cells per run, for a total of 204,000 PCR reactions using a device footprint of 10 cm(2). Experiments using RNA dilutions show this device achieves shot-noise-limited performance in quantifying single molecules, with a dynamic range of 10(4). We performed over 1200 single-cell measurements, demonstrating the use of this platform in the absolute quantification of both high- and low-abundance mRNA transcripts, as well as micro-RNAs that are not easily measured using alternative hybridization methods. We further apply the specificity and sensitivity of single-cell dPCR to performing measurements of RNA editing events in single cells. High-throughput dPCR provides a new tool in the arsenal of single-cell analysis methods, with a unique combination of speed, precision, sensitivity, and specificity. We anticipate this approach will enable new studies where high-performance single-cell measurements are essential, including the analysis of transcriptional noise, allelic imbalance, and RNA processing.

Valley current characterization of high current density resonant tunnelling diodes for terahertz-wave applications

NASA Astrophysics Data System (ADS)

Jacobs, K. J. P.; Stevens, B. J.; Baba, R.; Wada, O.; Mukai, T.; Hogg, R. A.

2017-10-01

We report valley current characterisation of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTDs) grown by metal-organic vapour phase epitaxy (MOVPE) for THz emission, with a view to investigate the origin of the valley current and optimize device performance. By applying a dual-pass fabrication technique, we are able to measure the RTD I-V characteristic for different perimeter/area ratios, which uniquely allows us to investigate the contribution of leakage current to the valley current and its effect on the PVCR from a single device. Temperature dependent (20 - 300 K) characteristics for a device are critically analysed and the effect of temperature on the maximum extractable power (PMAX) and the negative differential conductance (NDC) of the device is investigated. By performing theoretical modelling, we are able to explore the effect of typical variations in structural composition during the growth process on the tunnelling properties of the device, and hence the device performance.

Minority carrier diffusion length extraction in Cu2ZnSn(Se,S)4 solar cells

NASA Astrophysics Data System (ADS)

Gokmen, Tayfun; Gunawan, Oki; Mitzi, David B.

2013-09-01

We report measurement of minority carrier diffusion length (Ld) for high performance Cu2ZnSn(S,Se)4 (CZTSSe) solar cells in comparison with analogous Cu(In,Ga)(S,Se)2 (CIGSSe) devices. Our Ld extraction method involves performing systematic measurements of the internal quantum efficiency combined with separate capacitance-voltage measurement. This method also enables the measurement of the absorption coefficient of the absorber material as a function of wavelength in a finished device. The extracted values of Ld for CZTSSe samples are at least factor of 2 smaller than those for CIGSSe samples. Combined with minority carrier lifetime (τ) data measured by time-resolved photoluminescence, we deduce the minority carrier mobility (μe), which is also relatively low for the CZTSSe samples.

Temperature- and Intensity-Dependent Photovoltaic Measurements to Identify Dominant Recombination Pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandt, Riley E.; Mangan, Niall M.; Li, Jian V.

2016-11-21

In novel photovoltaic absorbers, it is often difficult to assess the root causes of low open-circuit voltages, which may be due to bulk recombination or sub-optimal contacts. In the present work, we discuss the role of temperature- and illumination-dependent device electrical measurements in quantifying and distinguishing these performance losses - in particular, for determining bounds on interface recombination velocities, band alignment, and minority carrier lifetime. We assess the accuracy of this approach by direct comparison to photoelectron spectroscopy. Then, we demonstrate how more computationally intensive model parameter fitting approaches can draw more insights from this broad measurement space. We applymore » this measurement and modeling approach to high-performance III-V and thin-film chalcogenide devices.« less

The Timer-Logger-Communicator for Continuous, Mobile Measurement of Wheelchair Pressure Reliefs

PubMed Central

Grip, Jeffrey C.; Merbitz, Charles T.

1985-01-01

A recently developed device which provides continuous, direct monitoring of the pressure-relief performance of persons confined to wheelchairs is reported. A custom portable computer records the data, which is transferred for analysis to an Apple IIe. The mobile computer can also signal the patient to relieve pressure based on preset criteria and the patient's performance. Teaching lift-offs to prevent ischial pressure sores is the object. Data collected with the device are used clinically and for research. Examples of such data are presented. The benefits of the device are reviewed.

Analysis of a digital RF memory in a signal-delay application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jelinek, D.A.

1992-03-01

Laboratory simulation of the approach of a radar fuze towards a target is an important factor in our ability to accurately measure the radar`s performance. This simulation is achieved, in part, by dynamically delaying and attenuating the radar`s transmitted pulse and sending the result back to the radar`s receiver. Historically, the device used to perform the dynamic delay has been a limiting factor in the evaluation of a radar`s performance and characteristics. A new device has been proposed that appears to have more capability than previous dynamic delay devices. This device is the digital RF memory. This report presents themore » results of an analysis of a digital RF memory used in a signal-delay application. 2 refs.« less

Performance of a Diaphragmed Microlens for a Packaged Microspectrometer

PubMed Central

Lo, Joe; Chen, Shih-Jui; Fang, Qiyin; Papaioannou, Thanassis; Kim, Eun-Sok; Gundersen, Martin; Marcu, Laura

2009-01-01

This paper describes the design, fabrication, packaging and testing of a microlens integrated in a multi-layered MEMS microspectrometer. The microlens was fabricated using modified PDMS molding to form a suspended lens diaphragm. Gaussian beam propagation model was used to measure the focal length and quantify M2 value of the microlens. A tunable calibration source was set up to measure the response of the packaged device. Dual wavelength separation by the packaged device was demonstrated by CCD imaging and beam profiling of the spectroscopic output. We demonstrated specific techniques to measure critical parameters of microoptics systems for future optimization of spectroscopic devices. PMID:22399943

Experimental measurement-device-independent quantum digital signatures over a metropolitan network

NASA Astrophysics Data System (ADS)

Yin, Hua-Lei; Wang, Wei-Long; Tang, Yan-Lin; Zhao, Qi; Liu, Hui; Sun, Xiang-Xiang; Zhang, Wei-Jun; Li, Hao; Puthoor, Ittoop Vergheese; You, Li-Xing; Andersson, Erika; Wang, Zhen; Liu, Yang; Jiang, Xiao; Ma, Xiongfeng; Zhang, Qiang; Curty, Marcos; Chen, Teng-Yun; Pan, Jian-Wei

2017-04-01

Quantum digital signatures (QDSs) provide a means for signing electronic communications with information-theoretic security. However, all previous demonstrations of quantum digital signatures assume trusted measurement devices. This renders them vulnerable against detector side-channel attacks, just like quantum key distribution. Here we exploit a measurement-device-independent (MDI) quantum network, over a metropolitan area, to perform a field test of a three-party MDI QDS scheme that is secure against any detector side-channel attack. In so doing, we are able to successfully sign a binary message with a security level of about 10-7. Remarkably, our work demonstrates the feasibility of MDI QDSs for practical applications.

A new laryngeal mask supraglottic airway device with integrated balloon line: a descriptive and comparative bench study

PubMed Central

Zhou, YingHai; Jew, Korinne

2016-01-01

Laryngeal masks are invasive devices for airway management placed in the supraglottic position. The Shiley™ laryngeal mask (Shiley™ LM) features an integrated inflation tube and airway shaft to facilitate product insertion and reduce the chance of tube occlusion when patients bite down. This study compared the Shiley LM to two other disposable laryngeal mask devices, the Ambu® AuraStraight™ and the LMA Unique™. Overall device design, tensile strength, flexibility of various structures, and sealing performance were measured. The Shiley LM is structurally stronger and its shaft is more resistant to compression than the other devices. The Shiley LM is generally less flexible than the other devices, but this relationship varies with device size. Sealing performance of the devices was similar in a bench assay. The results of this bench study demonstrate that the new Shiley LM resembles other commercially available laryngeal mask devices, though it exhibits greater tensile strength and lower flexibility. PMID:27843359

A new laryngeal mask supraglottic airway device with integrated balloon line: a descriptive and comparative bench study.

PubMed

Zhou, YingHai; Jew, Korinne

2016-01-01

Laryngeal masks are invasive devices for airway management placed in the supraglottic position. The Shiley™ laryngeal mask (Shiley™ LM) features an integrated inflation tube and airway shaft to facilitate product insertion and reduce the chance of tube occlusion when patients bite down. This study compared the Shiley LM to two other disposable laryngeal mask devices, the Ambu ® AuraStraight™ and the LMA Unique™. Overall device design, tensile strength, flexibility of various structures, and sealing performance were measured. The Shiley LM is structurally stronger and its shaft is more resistant to compression than the other devices. The Shiley LM is generally less flexible than the other devices, but this relationship varies with device size. Sealing performance of the devices was similar in a bench assay. The results of this bench study demonstrate that the new Shiley LM resembles other commercially available laryngeal mask devices, though it exhibits greater tensile strength and lower flexibility.

High performance quantum cascade lasers: Loss, beam stability, and gain engineering

NASA Astrophysics Data System (ADS)

Bouzi, Pierre Michel

Quantum Cascade (QC) lasers are semiconductor devices emitting in the mid-infrared (3-30 micron) and terahertz (30-300 micron) regions of the electromagnetic spectrum. Since their first demonstration by Jerome Faist et. al. in 1994, they have evolved very quickly into high performance devices and given rise to many applications such as trace-gas sensing, medical diagnosis, free-space communication, and light detection and ranging (LIDAR). In this thesis, we investigate a further increase of the performance of QC devices and, through meticulous device modeling and characterizations, gain a deeper understanding of several of their unique characteristics, especially their carrier transport and lifetime, their characteristic temperature, their waveguide loss and modal gain, their leakage current, and their transverse mode profile. First, in our quest to achieve higher performance, we investigate the effect of growth asymmetries on device transport characteristics. This investigation stems from recent studies on the role of interface roughness on intersubband scattering and device performance. Through a symmetric active core design, we find that interface roughness and ionized impurity scattering induced by dopant migration play a significant role in carrier transport through the device. Understanding how interface roughness affects intersubband scattering, in turn, we engineer the gain in QC devices by placing monolayer barriers at specific locations within the device band structure. These strategically placed additional thin barrier layers introduce roughness scattering into the device active region, thereby selectively decreasing the lower laser state lifetime and increasing population inversion necessary for laser action. Preliminary measurement results from modified devices reveal a 50% decrease in the emission broadening compared to the control structures, which should lead to a two-fold increase in gain. A special class of so-called "strong coupling" QC lasers recently emerged with high optical power and high efficiency at cryogenic temperatures. However their performances decay rather rapidly with temperature in both pulsed and continuous wave modes. Through detailed measurements and analysis, we investigate several possible causes of this shortcoming and propose design modifications for temperature performance improvement. While the strong coupling devices are efficient and powerful, their performance often suffers from unintentional and potentially harmful beam steering at high power. Here, we identify the root of this pointing instability to be from non-linear interactions between multiple transverse modes. And, to resolve this issue, we employ focused ion beam (FIB) milling to etch small lateral constrictions on top of the devices and fill them with metal. This has the effect of greatly reducing the intensity of higher order transverse modes as they propagate through the cavity. A good grasp of the microscopic details involved in QC device operations will result in better lasers, with high beam quality. This, in turn, will enable new applications, such as the detection of SO2 isotopologues near 7.4 micron, which is of particular importance for the study of ultraviolet photolysis and the sulfur cycle on Venus.

Sensor Measurement Strategies for Monitoring Offshore Wind and Wave Energy Devices

NASA Astrophysics Data System (ADS)

O'Donnell, Deirdre; Srbinovsky, Bruno; Murphy, Jimmy; Popovici, Emanuel; Pakrashi, Vikram

2015-07-01

While the potential of offshore wind and wave energy devices is well established and accepted, operations and maintenance issues are still not very well researched or understood. In this regard, scaled model testing has gained popularity over time for such devices at various technological readiness levels. The dynamic response of these devices are typically measured by different instruments during such scaled tests but agreed sensor choice, measurement and placement guidelines are still not in place. This paper compared the dynamic responses of some of these sensors from a scaled ocean wave testing to highlight the importance of sensor measurement strategies. The possibility of using multiple, cheaper sensors of seemingly inferior performance as opposed to the deployment of a small number of expensive and accurate sensors are also explored. An energy aware adaptive sampling theory is applied to highlight the possibility of more efficient computing when large volumes of data are available from the tested structures. Efficient sensor measurement strategies are expected to have a positive impact on the development of an device at different technological readiness levels while it is expected to be helpful in reducing operation and maintenance costs if such an approach is considered for the devices when they are in operation.

Bottom-up realization and electrical characterization of a graphene-based device.

PubMed

Maffucci, A; Micciulla, F; Cataldo, A; Miano, G; Bellucci, S

2016-03-04

We propose a bottom-up procedure to fabricate an easy-to-engineer graphene-based device, consisting of a microstrip-like circuit where few-layer graphene nanoplatelets are used to contact two copper electrodes. The graphene nanoplatelets are obtained by the microwave irradiation of intercalated graphite, i.e., an environmentally friendly, fast and low-cost procedure. The contact is created by a bottom-up process, driven by the application of a DC electrical field in the gap between the electrodes, yielding the formation of a graphene carpet. The electrical resistance of the device has been measured as a function of the gap length and device temperature. The possible use of this device as a gas sensor is demonstrated by measuring the sensitivity of its electrical resistance to the presence of gas. The measured results demonstrate a good degree of reproducibility in the fabrication process, and the competitive performance of devices, thus making the proposed technique potentially attractive for industrial applications.

Agreement and reading time for differently-priced devices for the digital capture of X-ray films.

PubMed

Salazar, Antonio José; Camacho, Juan Camilo; Aguirre, Diego Andrés

2012-03-01

We assessed the reliability of three digital capture devices: a film digitizer (which cost US $15,000), a flat-bed scanner (US $1800) and a digital camera (US $450). Reliability was measured as the agreement between six observers when reading images acquired from a single device and also in terms of the pair-device agreement. The images were 136 chest X-ray cases. The variables measured were the interstitial opacities distribution, interstitial patterns, nodule size and percentage pneumothorax size. The agreement between the six readers when reading images acquired from a single device was similar for the three devices. The pair-device agreements were moderate for all variables. There were significant differences in reading-time between devices: the mean reading-time for the film digitizer was 93 s, it was 59 s for the flat-bed scanner and 70 s for the digital camera. Despite the differences in their cost, there were no substantial differences in the performance of the three devices.

Properties of piezoresistive silicon nano-scale cantilevers with applications to BioNEMS

NASA Astrophysics Data System (ADS)

Arlett, Jessica Lynn

Over the last decade a great deal of interest has been raised in applications of Microelectromechanical Sensors [MEMS] for the detection of biological molecules and to the study of their forces of interaction. Experiments in these areas have included Force Spectroscopy (Chemical Force Microscopy), MEMS patch clamp technology, and surface stress sensors. All of these technologies suffer from limitations on temporal response and involve devices with active surface areas that are large compared to molecular dimensions. Biofunctionalized nanoelectromechanical systems (BioNEMS) have the potential to overcome both of these hurdles, offering important new prospects for single-molecule force assays that are amenable to large scale integration. Results are presented here on the characterization of piezoresistive silicon cantilevers with applications to BioNEMS devices. The cantilevers were characterized by studying their response in gaseous ambients under a number of drive conditions including magnetic, piezoelectric, and thermal actuation, in addition to passive detection of the thermomechanical response. The measurements were performed at liquid helium temperature, at room temperature, and over a range of pressures (atmospheric pressure to 30mT). Theoretical studies have been performed on the response of these devices to Brownian fluctuations in fluid, on the feasibility of these devices as surface stress sensors, and on improvements in device design as compared to piezoresistive surface stress sensors currently discussed in the literature. The devices were encapsulated in microfluidics and measurements were performed to show the noise floor in fluid. The piezoresistive response of the device in fluid was shown through the use of pulsatory fluidic drive. As a proof of concept, biodetection experiments are presented for biotin labeled beads. The biofunctionalization for the latter experiment was performed entirely within the microfluidics. A discussion of how these experiments can be extended to other cells, spores, and molecules is presented.

Photo-Detection on Narrow-Bandgap High-Mobility 2D Semiconductors

NASA Astrophysics Data System (ADS)

Charnas, Adam; Qiu, Gang; Deng, Yexin; Wang, Yixiu; Du, Yuchen; Yang, Lingming; Wu, Wenzhuo; Ye, Peide

Photo-detection and energy harvesting device concepts have been demonstrated widely in 2D materials such as graphene, TMDs, and black phosphorus. In this work, we demonstrate anisotropic photo-detection achieved using devices fabricated from hydrothermally grown narrow-bandgap high-mobility 2D semiconductor. Back-gated FETs were fabricated by transferring the 2D flakes onto a Si/SiO2 substrate and depositing various metal contacts across the flakes to optimize the access resistance for optoelectronic devices. Photo-responsivity was measured and mapped by slightly biasing the devices and shining a laser spot at different locations of the device to observe and map the resulting photo-generated current. Optimization of the Schottky barrier height for both n and p at the metal-2D interfaces using asymmetric contact engineering was performed to improve device performance.

Investigation of transport properties of coronene.TCNQ cocrystal microrods with coronene microrods and TCNQ microsheets

NASA Astrophysics Data System (ADS)

Wu, Hao-Di; Wang, Feng-Xia; Zhang, Meng; Pan, Ge-Bo

2015-07-01

Coronene.TCNQ cocrystal microrods, coronene microrods, and TCNQ microsheets were constructed by a drop-casting method. Prototype devices were fabricated and their field-effect-transistor (FET) performances were investigated. It is found that coronene.TCNQ microrods had exhibited an n-type characteristic and showed better FET performances than TCNQ microsheets.Coronene.TCNQ cocrystal microrods, coronene microrods, and TCNQ microsheets were constructed by a drop-casting method. Prototype devices were fabricated and their field-effect-transistor (FET) performances were investigated. It is found that coronene.TCNQ microrods had exhibited an n-type characteristic and showed better FET performances than TCNQ microsheets. Electronic supplementary information (ESI) available: Device fabrication and measurements. See DOI: 10.1039/c5nr02778k

Scaling of Performance in Liquid Propellant Rocket Engine Combustion Devices

NASA Technical Reports Server (NTRS)

Hulka, James R.

2008-01-01

This paper discusses scaling of combustion and combustion performance in liquid propellant rocket engine combustion devices. In development of new combustors, comparisons are often made between predicted performance in a new combustor and measured performance in another combustor with different geometric and thermodynamic characteristics. Without careful interpretation of some key features, the comparison can be misinterpreted and erroneous information used in the design of the new device. This paper provides a review of this performance comparison, including a brief review of the initial liquid rocket scaling research conducted during the 1950s and 1960s, a review of the typical performance losses encountered and how they scale, a description of the typical scaling procedures used in development programs today, and finally a review of several historical development programs to see what insight they can bring to the questions at hand.

Improved Devices for Collecting Sweat for Chemical Analysis

NASA Technical Reports Server (NTRS)

Feeback, Daniel L.; Clarke, Mark S. F.

2011-01-01

Improved devices have been proposed for collecting sweat for biochemical analysis especially for determination of the concentration of Ca2+ ions in sweat as a measure of loss of Ca from bones. Unlike commercially available sweat-collection patches used previously in monitoring osteoporosis and in qualitative screening for some drugs, the proposed devices would not allow evaporation of the volatile chemical components (mostly water) of sweat. Moreover, the proposed devices would be designed to enable determination of the volumes of collected sweat. From these volumes and the quantities of Ca2+ and/or other analytes as determined by other means summarized below, one could determine the concentrations of the analytes in sweat. A device according to the proposal would be flexible and would be worn like a commercial sweat-collection patch. It would be made of molded polydimethylsiloxane (silicone rubber) or other suitable material having properties that, for the purpose of analyzing sweat, are similar to those of glass. The die for molding the silicone rubber would be fabricated by a combination of lithography and electroplating. The die would reproducibly form, in the silicone rubber, a precisely defined number of capillary channels per unit area, each channel having a precisely defined volume. Optionally, electrodes for measuring the Ca2+ content of the sweat could be incorporated into the device. The volume of sweat collected in the capillary channels of the device would be determined from (1) the amount of light or radio waves of a given wavelength absorbed by the device and (2) the known geometry of the array of capillary channels. Then, in one of two options, centrifugation would be performed to move the sweat from the capillary tubes to the region containing the electrodes, which would be used to measure the Ca2+ content by a standard technique. In the other option, centrifugation would be performed to remove the sweat from the device to make the sweat available to other analytical instruments for measuring concentrations of substances other than Ca2+.

Improved Devices for Collecting Sweat for Chemical Analysis

NASA Technical Reports Server (NTRS)

Feedback, Daniel L.; Clarke, Mark S. F.

2011-01-01

Improved devices have been proposed for collecting sweat for biochemical analysis - especially for determination of the concentration of Ca2+ ions in sweat as a measure of loss of Ca from bones. Unlike commercially available sweat-collection patches used previously in monitoring osteoporosis and in qualitative screening for some drugs, the proposed devices would not allow evaporation of the volatile chemical components (mostly water) of sweat. Moreover, the proposed devices would be designed to enable determination of the volumes of collected sweat. From these volumes and the quantities of Ca(2+) and/or other analytes as determined by other means summarized below, one could determine the concentrations of the analytes in sweat. A device according to the proposal would be flexible and would be worn like a commercial sweat-collection patch. It would be made of molded polydimethylsiloxane (silicone rubber) or other suitable material having properties that, for the purpose of analyzing sweat, are similar to those of glass. The die for molding the silicone rubber would be fabricated by a combination of lithography and electroplating. The die would reproducibly form, in the silicone rubber, a precisely defined number of capillary channels per unit area, each channel having a precisely defined volume. Optionally, electrodes for measuring the Ca(2+) content of the sweat could be incorporated into the device. The volume of sweat collected in the capillary channels of the device would be determined from (1) the amount of light or radio waves of a given wavelength absorbed by the device and (2) the known geometry of the array of capillary channels. Then, in one of two options, centrifugation would be performed to move the sweat from the capillary tubes to the region containing the electrodes, which would be used to measure the Ca(2+) content by a standard technique. In the other option, centrifugation would be performed to remove the sweat from the device to make the sweat available to other analytical instruments for measuring concentrations of substances other than Ca(2+).

Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beck, Patrick R.

2010-01-07

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current ormore » leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.« less

Automated intracranial pressure-controlled cerebrospinal fluid external drainage with LiquoGuard.

PubMed

Linsler, Stefan; Schmidtke, Mareike; Steudel, Wolf Ingo; Kiefer, Michael; Oertel, Joachim

2013-08-01

LiquoGuard is a new device for intracranial pressure (ICP)-controlled drainage of cerebrospinal fluid (CSF). This present study evaluates the accuracy of ICP measurement via the LiquoGuard device in comparison with Spiegelberg. Thus, we compared data ascertained from simultaneous measurement of ICP using tip-transducer and tip-sensor devices. A total of 1,764 monitoring hours in 15 patients (range, 52-219 h) were analysed. All patients received an intraventricular Spiegelberg III probe with the drainage catheter connected to the LiquoGuard system. ICP reading of both devices was performed on an hourly basis. Statistical analysis was done by applying Pearson correlation and Wilcoxon-matched pair test (p < 0.05). Mean ICP values were 11 ± 5 mmHg (Spiegelberg) and 10 ± 7 mmHg (LiquoGuard); the values measured with both devices correlated well (p = 0.001; Pearson correlation =0.349; n = 1,764). In two of the 15 patients with slit ventricles, episodes of significant differences in measured values could be observed. Both patients suffering from slit ventricles failed to produce reliable measurement with the external transducer of the LiquoGuard. LiquoGuard is a valuable new device for ICP-controlled CSF drainage. However, LiquoGuard tends to provide misleading results in slit ventricles. Thus, before these drawbacks are further analysed, the authors recommend additional ICP measurement with internal tip-sensor devices to avoid dangerous erroneous interpretation of ICP data.

Microfluidic method for measuring viscosity using images from smartphone

NASA Astrophysics Data System (ADS)

Kim, Sooyeong; Kim, Kyung Chun; Yeom, Eunseop

2018-05-01

The viscosity of a fluid is the most important characteristic in fluid rheology. Many microfluidic devices have been proposed for easily measuring the fluid viscosity of small samples. A hybrid system consisting of a smartphone and microfluidic device can offer a mobile laboratory for performing a wide range of detection and analysis functions related to healthcare. In this study, a new mobile sensing method based on a microfluidic device was proposed for fluid viscosity measurements. By separately delivering sample and reference fluids into the two inlets of a Y-shaped microfluidic device, an interfacial line is induced at downstream of the device. Because the interfacial width (W) between the sample and reference fluid flows was determined by their pressure ratio, the viscosity (μ) of the sample could be estimated by measuring the interfacial width. To distinguish the interfacial width of a sample, optical images of the flows at downstream of the Y-shaped microfluidic device were acquired using a smartphone. To check the measurement accuracy of the proposed method, the viscosities of glycerol mixtures were compared with those measured by a conventional viscometer. The proposed technique was applied to monitor the variations in blood and oil samples depending on storage or rancidity. We expect that this mobile sensing method based on a microfluidic device could be utilized as a viscometer with significant advantages in terms of mobility, ease-of-operation, and data management.

A neural network device for on-line particle identification in cosmic ray experiments

NASA Astrophysics Data System (ADS)

Scrimaglio, R.; Finetti, N.; D'Altorio, L.; Rantucci, E.; Raso, M.; Segreto, E.; Tassoni, A.; Cardarilli, G. C.

2004-05-01

On-line particle identification is one of the main goals of many experiments in space both for rare event studies and for optimizing measurements along the orbital trajectory. Neural networks can be a useful tool for signal processing and real time data analysis in such experiments. In this document we report on the performances of a programmable neural device which was developed in VLSI analog/digital technology. Neurons and synapses were accomplished by making use of Operational Transconductance Amplifier (OTA) structures. In this paper we report on the results of measurements performed in order to verify the agreement of the characteristic curves of each elementary cell with simulations and on the device performances obtained by implementing simple neural structures on the VLSI chip. A feed-forward neural network (Multi-Layer Perceptron, MLP) was implemented on the VLSI chip and trained to identify particles by processing the signals of two-dimensional position-sensitive Si detectors. The radiation monitoring device consisted of three double-sided silicon strip detectors. From the analysis of a set of simulated data it was found that the MLP implemented on the neural device gave results comparable with those obtained with the standard method of analysis confirming that the implemented neural network could be employed for real time particle identification.

A New Cuffless Device for Measuring Blood Pressure: A Real-Life Validation Study.

PubMed

Schoot, Tessa S; Weenk, Mariska; van de Belt, Tom H; Engelen, Lucien J L P G; van Goor, Harry; Bredie, Sebastian J H

2016-05-05

Cuffless blood pressure (BP) monitoring devices, based on pulse transit time, are being developed as an easy-to-use, more convenient, fast, and relatively cheap alternative to conventional BP measuring devices based on cuff occlusion. Thereby they may provide a great alternative to BP self-measurement. The objective of our study was to evaluate the performance of the first release of the Checkme Health Monitor (Viatom Technology), a cuffless BP monitor, in a real-life setting. Furthermore, we wanted to investigate whether the posture of the volunteer and the position of the device relative to the heart level would influence its outcomes. Study volunteers fell into 3 BP ranges: high (>160 mmHg), normal (130-160 mmHg), and low (<130 mmHg). All requirements for test environment, observer qualification, volunteer recruitment, and BP measurements were met according to the European Society of Hypertension International Protocol (ESH-IP) for the validation of BP measurement devices. After calibrating the Checkme device, we measured systolic BP with Checkme and a validated, oscillometric reference BP monitor (RM). Measurements were performed in randomized order both in supine and in sitting position, and with Checkme at and above heart level. We recruited 52 volunteers, of whom we excluded 15 (12 due to calibration failure with Checkme, 3 due to a variety of reasons). The remaining 37 volunteers were divided into low (n=14), medium (n=13), and high (n=10) BP ranges. There were 18 men and 19 women, with a mean age of 54.1 (SD 14.5) years, and mean recruitment systolic BP of 141.7 (SD 24.7) mmHg. BP results obtained by RM and Checkme correlated well. In the supine position, the difference between the RM and Checkme was >5 mmHg in 17 of 37 volunteers (46%), of whom 9 of 37 (24%) had a difference >10 mmHg and 5 of 37 (14%) had a difference >15 mmHg. BP obtained with Checkme correlated well with RM BP, particularly in the position (supine) in which the device was calibrated. These preliminary results are promising for conducting further research on cuffless BP measurement in the clinical and outpatient settings.

A New Framework for Quantifying Lidar Uncertainty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newman, Jennifer, F.; Clifton, Andrew; Bonin, Timothy A.

2017-03-24

As wind turbine sizes increase and wind energy expands to more complex and remote sites, remote sensing devices such as lidars are expected to play a key role in wind resource assessment and power performance testing. The switch to remote sensing devices represents a paradigm shift in the way the wind industry typically obtains and interprets measurement data for wind energy. For example, the measurement techniques and sources of uncertainty for a remote sensing device are vastly different from those associated with a cup anemometer on a meteorological tower. Current IEC standards discuss uncertainty due to mounting, calibration, and classificationmore » of the remote sensing device, among other parameters. Values of the uncertainty are typically given as a function of the mean wind speed measured by a reference device. However, real-world experience has shown that lidar performance is highly dependent on atmospheric conditions, such as wind shear, turbulence, and aerosol content. At present, these conditions are not directly incorporated into the estimated uncertainty of a lidar device. In this presentation, we propose the development of a new lidar uncertainty framework that adapts to current flow conditions and more accurately represents the actual uncertainty inherent in lidar measurements under different conditions. In this new framework, sources of uncertainty are identified for estimation of the line-of-sight wind speed and reconstruction of the three-dimensional wind field. These sources are then related to physical processes caused by the atmosphere and lidar operating conditions. The framework is applied to lidar data from an operational wind farm to assess the ability of the framework to predict errors in lidar-measured wind speed.« less

A new device for continuous monitoring the CO2 dissolved in water

NASA Astrophysics Data System (ADS)

de Gregorio, S.; Camarda, M.; Cappuzzo, S.; Giudice, G.; Gurrieri, S.; Longo, M.

2009-04-01

The measurements of dissolved CO2 in water are common elements of industrial processes and scientific research. In order to perform gas dissolved measurements is required to separate the dissolved gaseous phase from water. We developed a new device able to separate the gases phase directly in situ and well suitable for continuous measuring the CO2 dissolved in water. The device is made by a probe of a polytetrafluorethylene (PTFE) tube connected to an I.R. spectrophotometer (I.R.) and a pump. The PTFE is a polymeric semi-permeable membrane and allows the permeation of gas in the system. Hence, this part of the device is dipped in water in order to equilibrate the probe headspace with the dissolved gases. The partial pressure of the gas i in the headspace at equilibrium (Pi) follows the Henry's law: Pi=Hi•Ci, where Hi is the Henry's constant and Ci is the dissolved concentration of gas i. After the equilibrium is achieved, the partial pressure of CO2 inside the tube is equal to the partial pressure of dissolved CO2. The concentration of CO2 is measured by the I.R. connected to the tube. The gas is moved from the tube headspace to the I.R. by using the pump. In order to test the device and assess the best operating condition, several experimental were performed in laboratory. All the test were executed in a special apparatus where was feasible to create controlled atmospheres. Afterward the device has been placed in a draining tunnel sited in the Mt. Etna Volcano edifice (Italy). The monitored groundwater intercepts the Pernicana Fault, along which degassing phenomena are often observed. The values recorded by the station result in agreement with monthly directly measurements of dissolved CO2 partial pressure.

77 FR 11199 - Visual-Manual NHTSA Driver Distraction Guidelines for In-Vehicle Electronic Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

...The National Highway Traffic Safety Administration (NHTSA) is concerned about the effects of distraction due to drivers' use of electronic devices on motor vehicle safety. Consequently, NHTSA is issuing nonbinding, voluntary NHTSA Driver Distraction Guidelines (NHTSA Guidelines) to promote safety by discouraging the introduction of excessively distracting devices in vehicles. This notice details the contents of the first phase of the NHTSA Driver Distraction Guidelines. These NHTSA Guidelines cover original equipment in-vehicle device secondary tasks (communications, entertainment, information gathering, and navigation tasks not required to drive are considered secondary tasks) performed by the driver through visual-manual means (meaning the driver looking at a device, manipulating a device-related control with the driver's hand, and watching for visual feedback). The proposed NHTSA Guidelines list certain secondary, non-driving related tasks that, based on NHTSA's research, are believed by the agency to interfere inherently with a driver's ability to safely control the vehicle. The Guidelines recommend that those in-vehicle devices be designed so that they cannot be used by the driver to perform such tasks while the driver is driving. For all other secondary, non-driving-related visual-manual tasks, the NHTSA Guidelines specify a test method for measuring the impact of task performance on driving safety while driving and time-based acceptance criteria for assessing whether a task interferes too much with driver attention to be suitable to perform while driving. If a task does not meet the acceptance criteria, the NHTSA Guidelines recommend that in- vehicle devices be designed so that the task cannot be performed by the driver while driving. In addition to identifying inherently distracting tasks and providing a means for measuring and evaluating the level of distraction associated with other non-driving-related tasks, the NHTSA Guidelines contain several design recommendations for in-vehicle devices in order to minimize their potential for distraction. NHTSA seeks comments on these NHTSA Guidelines and any suggestions for how to improve them so as to better enhance motor vehicle safety.

Temperature measurement with industrial color camera devices

NASA Astrophysics Data System (ADS)

Schmidradler, Dieter J.; Berndorfer, Thomas; van Dyck, Walter; Pretschuh, Juergen

1999-05-01

This paper discusses color camera based temperature measurement. Usually, visual imaging and infrared image sensing are treated as two separate disciplines. We will show, that a well selected color camera device might be a cheaper, more robust and more sophisticated solution for optical temperature measurement in several cases. Herein, only implementation fragments and important restrictions for the sensing element will be discussed. Our aim is to draw the readers attention to the use of visual image sensors for measuring thermal radiation and temperature and to give reasons for the need of improved technologies for infrared camera devices. With AVL-List, our partner of industry, we successfully used the proposed sensor to perform temperature measurement for flames inside the combustion chamber of diesel engines which finally led to the presented insights.

Improved perceptual-motor performance measurement system

NASA Technical Reports Server (NTRS)

Parker, J. F., Jr.; Reilly, R. E.

1969-01-01

Battery of tests determines the primary dimensions of perceptual-motor performance. Eighteen basic measures range from simple tests to sophisticated electronic devices. Improved system has one unit for the subject containing test display and response elements, and one for the experimenter where test setups, programming, and scoring are accomplished.

Lifespan-on-a-chip: microfluidic chambers for performing lifelong observation of C. elegans†

PubMed Central

Hulme, S. Elizabeth; Shevkoplyas, Sergey S.; McGuigan, Alison P.; Apfeld, Javier; Fontana, Walter

2011-01-01

This article describes the fabrication of a microfluidic device for the liquid culture of many individual nematode worms (Caenorhabditis elegans) in separate chambers. Each chamber houses a single worm from the fourth larval stage until death, and enables examination of a population of individual worms for their entire adult lifespans. Adjacent to the chambers, the device includes microfluidic worm clamps, which enable periodic, temporary immobilization of each worm. The device made it possible to track changes in body size and locomotion in individual worms throughout their lifespans. This ability to perform longitudinal measurements within the device enabled the identification of age-related phenotypic changes that correlate with lifespan in C. elegans. PMID:20162234

Broadly available imaging devices enable high-quality low-cost photometry.

PubMed

Christodouleas, Dionysios C; Nemiroski, Alex; Kumar, Ashok A; Whitesides, George M

2015-09-15

This paper demonstrates that, for applications in resource-limited environments, expensive microplate spectrophotometers that are used in many central laboratories for parallel measurement of absorbance of samples can be replaced by photometers based on inexpensive and ubiquitous, consumer electronic devices (e.g., scanners and cell-phone cameras). Two devices, (i) a flatbed scanner operating in transmittance mode and (ii) a camera-based photometer (constructed from a cell phone camera, a planar light source, and a cardboard box), demonstrate the concept. These devices illuminate samples in microtiter plates from one side and use the RGB-based imaging sensors of the scanner/camera to measure the light transmitted to the other side. The broadband absorbance of samples (RGB-resolved absorbance) can be calculated using the RGB color values of only three pixels per microwell. Rigorous theoretical analysis establishes a well-defined relationship between the absorbance spectrum of a sample and its corresponding RGB-resolved absorbance. The linearity and precision of measurements performed with these low-cost photometers on different dyes, which absorb across the range of the visible spectrum, and chromogenic products of assays (e.g., enzymatic, ELISA) demonstrate that these low-cost photometers can be used reliably in a broad range of chemical and biochemical analyses. The ability to perform accurate measurements of absorbance on liquid samples, in parallel and at low cost, would enable testing, typically reserved for well-equipped clinics and laboratories, to be performed in circumstances where resources and expertise are limited.

Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO2) thin films

NASA Astrophysics Data System (ADS)

Nordin, N.; Hashim, U.; Azizah, N.

2016-07-01

Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO2) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM. Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.

Measuring the Impact of Cognitive Prosthetics on the Daily Life of People with Dementia and Their Carers

NASA Astrophysics Data System (ADS)

Meiland, Franka; Dröes, Rose-Marie; Sävenstedt, Stefan

Assistive technologies to support persons with dementia and their carers are used increasingly often. However, little is known about the effectiveness of most assistive devices. Much technology is put on the market without having been properly tested with potential end-users. To increase the chance that an assistive device is well accepted and useful for the target group, it is important, especially in the case of disabled persons, to involve potential users in the development process and to evaluate the impact of using the device on them before implementing it in the daily care and support. When evaluating the impact, decisions have to be made regarding the selection of measuring instruments. Important considerations in the selection process are the underlying domains to be addressed by the assistive technology, the target group and the availability of standardized instruments with good psychometric properties. In this chapter the COGKNOW project is used as a case example to explain how the impact of cognitive prosthetics on the daily lives of people with dementia and their carers can be measured. In COGKNOW a cognitive prosthetic device is being developed to improve the quality of life and autonomy of persons with dementia and to help them to remember and remind, to have social contact, to perform daily activities and to enhance feelings of safety. For all these areas, potential measuring instruments are described. Besides (standardized) measuring instruments, other data collection methods are used as well, such as semi-structured interviews and observations, diaries and in situ measurement. Within the COGKNOW project a first uncontrolled small-scale impact measurement takes place during the development process of the assistive device. However, it is recommended to perform a larger randomized controlled study as soon as the final product is ready to evaluate the impact of the device on persons with dementia and carers before it is released on the market.

Reconstruction-free sensitive wavefront sensor based on continuous position sensitive detectors.

PubMed

Godin, Thomas; Fromager, Michael; Cagniot, Emmanuel; Brunel, Marc; Aït-Ameur, Kamel

2013-12-01

We propose a new device that is able to perform highly sensitive wavefront measurements based on the use of continuous position sensitive detectors and without resorting to any reconstruction process. We demonstrate experimentally its ability to measure small wavefront distortions through the characterization of pump-induced refractive index changes in laser material. In addition, it is shown using computer-generated holograms that this device can detect phase discontinuities as well as improve the quality of sharp phase variations measurements. Results are compared to reference Shack-Hartmann measurements, and dramatic enhancements are obtained.

A mercury flow meter for ion thruster testing. [response time, thermal sensitivity

NASA Technical Reports Server (NTRS)

Wilbur, P. J.

1973-01-01

The theory of operation of the thermal flow meter is presented, and a theoretical model is used to determine design parameters for a device capable of measuring mercury flows in the range of 0 to 5 gm/hr. Flow meter construction is described. Tests performed using a positive displacement mercury pump as well as those performed with the device in the feed line of an operating thruster are discussed. A flow meter response time of about a minute and a sensitivity of about 10 mv/gm/hr are demonstrated. Additional work to relieve a sensitivity of the device to variations in ambient temperature is indicated to improve its quantitative performance.

The effects of control order, feedback, practice, and input device on tracking performance and perceived workload

NASA Technical Reports Server (NTRS)

Hancock, P. A.; Robinson, M. A.

1989-01-01

The present experiment examined the influence of several task-related factors on tracking performance and concomitant workload. The manipulated factors included tracking order, the presence or absence of knowledge of performance, and the control device. Summed root mean square error (rmse) and perceived workload were measured at the termination of each trial. Perceived workload was measured using the NASA Task Load Index (TLX) and the Subjective Workload Assessment Technique (SWAT). Results indicated a large and expected effect for track order on both performance and the perception of load. In general, trackball input was more accurate and judged for lower load than input using a mouse. The presence or absence of knowledge of performance had little effect on either performance or workload. There were a number of interactions between factors shown in performance that were mirrored by perceived workload scores. Results from each workload scale were equivalent in terms of sensitivity to task manipulations. The pattern of results affirm the utility of these workload measures in assessing the imposed load of multiple task-related variables.

The Measurement of Spectral Characteristics and Composition of Radiation in Atlas with MEDIPIX2-USB Devices

NASA Astrophysics Data System (ADS)

Campbell, M.; Doležal, Z.; Greiffenberg, D.; Heijne, E.; Holy, T.; Idárraga, J.; Jakůbek, J.; Král, V.; Králík, M.; Lebel, C.; Leroy, C.; Llopart, X.; Lord, G.; Maneuski, D.; Ouellette, O.; Sochor, V.; Pospíšil, S.; Suk, M.; Tlustos, L.; Vykydal, Z.; Wilhelm, I.

2008-06-01

A network of devices to perform real-time measurements of the spectral characteristics and composition of radiation in the ATLAS detector and cavern during its operation is being built. This system of detectors will be a stand alone system fully capable of delivering real-time images of fluxes and spectral composition of different particle species including slow and fast neutrons. The devices are based on MEDIPIX2 pixel silicon detectors that will be operated via active USB cables and USB-Ethernet extenders through an Ethernet network by a PC located in the USA15 ATLAS control room. The installation of 14 devices inside ATLAS (detector and cavern) is in progress.

Predicting the performance of a power amplifier using large-signal circuit simulations of an AlGaN/GaN HFET model

NASA Astrophysics Data System (ADS)

Bilbro, Griff L.; Hou, Danqiong; Yin, Hong; Trew, Robert J.

2009-02-01

We have quantitatively modeled the conduction current and charge storage of an HFET in terms its physical dimensions and material properties. For DC or small-signal RF operation, no adjustable parameters are necessary to predict the terminal characteristics of the device. Linear performance measures such as small-signal gain and input admittance can be predicted directly from the geometric structure and material properties assumed for the device design. We have validated our model at low-frequency against experimental I-V measurements and against two-dimensional device simulations. We discuss our recent extension of our model to include a larger class of electron velocity-field curves. We also discuss the recent reformulation of our model to facilitate its implementation in commercial large-signal high-frequency circuit simulators. Large signal RF operation is more complex. First, the highest CW microwave power is fundamentally bounded by a brief, reversible channel breakdown in each RF cycle. Second, the highest experimental measurements of efficiency, power, or linearity always require harmonic load pull and possibly also harmonic source pull. Presently, our model accounts for these facts with an adjustable breakdown voltage and with adjustable load impedances and source impedances for the fundamental frequency and its harmonics. This has allowed us to validate our model for large signal RF conditions by simultaneously fitting experimental measurements of output power, gain, and power added efficiency of real devices. We show that the resulting model can be used to compare alternative device designs in terms of their large signal performance, such as their output power at 1dB gain compression or their third order intercept points. In addition, the model provides insight into new device physics features enabled by the unprecedented current and voltage levels of AlGaN/GaN HFETs, including non-ohmic resistance in the source access regions and partial depletion of the 2DEG in the drain access region.

Direct evaluation of influence of electron damage on the subcell performance in triple-junction solar cells using photoluminescence decays.

PubMed

Tex, David M; Nakamura, Tetsuya; Imaizumi, Mitsuru; Ohshima, Takeshi; Kanemitsu, Yoshihiko

2017-05-16

Tandem solar cells are suited for space applications due to their high performance, but also have to be designed in such a way to minimize influence of degradation by the high energy particle flux in space. The analysis of the subcell performance is crucial to understand the device physics and achieve optimized designs of tandem solar cells. Here, the radiation-induced damage of inverted grown InGaP/GaAs/InGaAs triple-junction solar cells for various electron fluences are characterized using conventional current-voltage (I-V) measurements and time-resolved photoluminescence (PL). The conversion efficiencies of the entire device before and after damage are measured with I-V curves and compared with the efficiencies predicted from the time-resolved method. Using the time-resolved data the change in the carrier dynamics in the subcells can be discussed. Our optical method allows to predict the absolute electrical conversion efficiency of the device with an accuracy of better than 5%. While both InGaP and GaAs subcells suffered from significant material degradation, the performance loss of the total device can be completely ascribed to the damage in the GaAs subcell. This points out the importance of high internal electric fields at the operating point.

Evaluating the Validity of Current Mainstream Wearable Devices in Fitness Tracking Under Various Physical Activities: Comparative Study.

PubMed

Xie, Junqing; Wen, Dong; Liang, Lizhong; Jia, Yuxi; Gao, Li; Lei, Jianbo

2018-04-12

Wearable devices have attracted much attention from the market in recent years for their fitness monitoring and other health-related metrics; however, the accuracy of fitness tracking results still plays a major role in health promotion. The aim of this study was to evaluate the accuracy of a host of latest wearable devices in measuring fitness-related indicators under various seminatural activities. A total of 44 healthy subjects were recruited, and each subject was asked to simultaneously wear 6 devices (Apple Watch 2, Samsung Gear S3, Jawbone Up3, Fitbit Surge, Huawei Talk Band B3, and Xiaomi Mi Band 2) and 2 smartphone apps (Dongdong and Ledongli) to measure five major health indicators (heart rate, number of steps, distance, energy consumption, and sleep duration) under various activity states (resting, walking, running, cycling, and sleeping), which were then compared with the gold standard (manual measurements of the heart rate, number of steps, distance, and sleep, and energy consumption through oxygen consumption) and calculated to determine their respective mean absolute percentage errors (MAPEs). Wearable devices had a rather high measurement accuracy with respect to heart rate, number of steps, distance, and sleep duration, with a MAPE of approximately 0.10, whereas poor measurement accuracy was observed for energy consumption (calories), indicated by a MAPE of up to 0.44. The measurements varied for the same indicator measured by different fitness trackers. The variation in measurement of the number of steps was the highest (Apple Watch 2: 0.42; Dongdong: 0.01), whereas it was the lowest for heart rate (Samsung Gear S3: 0.34; Xiaomi Mi Band 2: 0.12). Measurements differed insignificantly for the same indicator measured under different states of activity; the MAPE of distance and energy measurements were in the range of 0.08 to 0.17 and 0.41 to 0.48, respectively. Overall, the Samsung Gear S3 performed the best for the measurement of heart rate under the resting state (MAPE of 0.04), whereas Dongdong performed the best for the measurement of the number of steps under the walking state (MAPE of 0.01). Fitbit Surge performed the best for distance measurement under the cycling state (MAPE of 0.04), and Huawei Talk Band B3 performed the best for energy consumption measurement under the walking state (MAPE of 0.17). At present, mainstream devices are able to reliably measure heart rate, number of steps, distance, and sleep duration, which can be used as effective health evaluation indicators, but the measurement accuracy of energy consumption is still inadequate. Fitness trackers of different brands vary with regard to measurement of indicators and are all affected by the activity state, which indicates that manufacturers of fitness trackers need to improve their algorithms for different activity states. ©Junqing Xie, Dong Wen, Lizhong Liang, Yuxi Jia, Li Gao, Jianbo Lei. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 12.04.2018.

Status of the project TRAPSENSOR: Performance of the laser-desorption ion source

NASA Astrophysics Data System (ADS)

Cornejo, J. M.; Lorenzo, A.; Renisch, D.; Block, M.; Düllmann, Ch. E.; Rodríguez, D.

2013-12-01

Penning traps provide mass measurements on atomic nuclei with the highest accuracy and sensitivity. Depending on the experiment and on the physics goal, a relative mass uncertainty varying from 10-7 to below 10-11 is required. Regarding sensitivity, the use of only one ion for the measurement is crucial, either to perform mass measurements on superheavy elements (SHE), or to reach δm/m≈10-11 in order to contribute to the direct determination of the mass of the electron-antineutrino with accurate mass measurements on specific nuclei. This has motivated the development of a new technique called Quantum Sensor based on a laser-cooled ion stored in a Penning trap, to perform mass measurements using fluorescence photons instead of electronic detection. The device is currently under development at the University of Granada (Spain) within the project TRAPSENSOR. We describe the physics which motivates the construction of this device, the expected performance of the Quantum Sensor compared to that from existing techniques, and briefly present the main components of the project. As a specific aspect of the project, the performance of the laser-desorption ion source utilized to produce calcium, rhenium and osmium ions at different kinetic energies is presented.

Development of a new instrument for direct skin friction measurements

NASA Technical Reports Server (NTRS)

Vakili, A. D.; Wu, J. M.

1986-01-01

A device developed for the direct measurement of wall shear stress generated by flows is described. Simple and symmetric in design with optional small moving mass and no internal friction, the features employed in the design eliminate most of the difficulties associated with the traditional floating element balances. The device is basically small and can be made in various sizes. Vibration problems associated with the floating element skin friction balances were found to be minimized due to the design symmetry and optional damping provided. The design eliminates or reduces the errors associated with conventional floating element devices: such as errors due to gaps, pressure gradient, acceleration, heat transfer, and temperature change. The instrument is equipped with various sensing systems and the output signal is a linear function of the wall shear stress. Dynamic measurements could be made in a limited range and measurements in liquids could be performed readily. Measurement made in the three different tunnels show excellent agreement with data obtained by the floating element devices and other techniques.

Scientific charge-coupled devices

NASA Technical Reports Server (NTRS)

Janesick, James R.; Elliott, Tom; Collins, Stewart; Blouke, Morley M.; Freeman, Jack

1987-01-01

The charge-coupled device dominates an ever-increasing variety of scientific imaging and spectroscopy applications. Recent experience indicates, however, that the full potential of CCD performance lies well beyond that realized in devices currently available.Test data suggest that major improvements are feasible in spectral response, charge collection, charge transfer, and readout noise. These properties, their measurement in existing CCDs, and their potential for future improvement are discussed in this paper.

Indirect Blood Pressure Measuring Device

NASA Technical Reports Server (NTRS)

Hum, L.; Cole, C. E.

1973-01-01

Design and performance of a blood pressure recording device for pediatric use are reported. A strain gage transducer with a copper-beryllium strip as force sensing element is used to monitor skin movements and to convert them into electrical signals proportional to those displacements. Experimental tests with this device in recording of force developed above the left femoral artery of a dog accurately produced a blood pressure curve.

Enhanced Lifetime of Polymer Solar Cells by Surface Passivation of Metal Oxide Buffer Layers.

PubMed

Venkatesan, Swaminathan; Ngo, Evan; Khatiwada, Devendra; Zhang, Cheng; Qiao, Qiquan

2015-07-29

The role of electron selective interfaces on the performance and lifetime of polymer solar cells were compared and analyzed. Bilayer interfaces consisting of metal oxide films with cationic polymer modification namely poly ethylenimine ethoxylated (PEIE) were found to enhance device lifetime compared to bare metal oxide films when used as an electron selective cathode interface. Devices utilizing surface-modified metal oxide layers showed enhanced lifetimes, retaining up to 85% of their original efficiency when stored in ambient atmosphere for 180 days without any encapsulation. The work function and surface potential of zinc oxide (ZnO) and ZnO/PEIE interlayers were evaluated using Kelvin probe and Kelvin probe force microscopy (KPFM) respectively. Kelvin probe measurements showed a smaller reduction in work function of ZnO/PEIE films compared to bare ZnO films when aged in atmospheric conditions. KPFM measurements showed that the surface potential of the ZnO surface drastically reduces when stored in ambient air for 7 days because of surface oxidation. Surface oxidation of the interface led to a substantial decrease in the performance in aged devices. The enhancement in the lifetime of devices with a bilayer interface was correlated to the suppressed surface oxidation of the metal oxide layers. The PEIE passivated surface retained a lower Fermi level when aged, which led to lower trap-assisted recombination at the polymer-cathode interface. Further photocharge extraction by linearly increasing voltage (Photo-CELIV) measurements were performed on fresh and aged samples to evaluate the field required to extract maximum charges. Fresh devices with a bare ZnO cathode interlayer required a lower field than devices with ZnO/PEIE cathode interface. However, aged devices with ZnO required a much higher field to extract charges while aged devices with ZnO/PEIE showed a minor increase compared to the fresh devices. Results indicate that surface modification can act as a suitable passivation layer to suppress oxidation in metal oxide thin films for enhanced lifetime in inverted organic solar cells.

Electronic adherence monitoring device performance and patient acceptability: a randomized control trial.

PubMed

Chan, Amy Hai Yan; Stewart, Alistair William; Harrison, Jeff; Black, Peter Nigel; Mitchell, Edwin Arthur; Foster, Juliet Michelle

2017-05-01

To investigate the performance and patient acceptability of an inhaler electronic monitoring device in a real-world childhood asthma population. Children 6 to 15 years presenting with asthma to the hospital emergency department and prescribed inhaled corticosteroids were included. Participants were randomized to receive a device with reminder features enabled or disabled for use with their preventer. Device quality control tests were conducted. Questionnaires on device acceptability, utility and ergonomics were completed at six months. A total of 1306 quality control tests were conducted; 84% passed pre-issue and 87% return testing. The most common failure reason was actuation under-recording. Acceptability scores were high, with higher scores in the reminder than non-reminder group (median, 5 th -95 th percentile: 4.1, 3.1-5.0 versus 3.7, 2.3-4.8; p < 0.001). Most (>90%) rated the device easy to use. Feedback was positive across five themes: device acceptability, ringtone acceptability, suggestions for improvement, effect on medication use, and effect on asthma control. This study investigates electronic monitoring device performance and acceptability in children using quantitative and qualitative measures. Results indicate satisfactory reliability, although failure rates of 13-16% indicate the importance of quality control. Favorable acceptability ratings support the use of these devices in children.

Study on the system-level test method of digital metering in smart substation

NASA Astrophysics Data System (ADS)

Zhang, Xiang; Yang, Min; Hu, Juan; Li, Fuchao; Luo, Ruixi; Li, Jinsong; Ai, Bing

2017-03-01

Nowadays, the test methods of digital metering system in smart substation are used to test and evaluate the performance of a single device, but these methods can only effectively guarantee the accuracy and reliability of the measurement results of a digital metering device in a single run, it does not completely reflect the performance when each device constitutes a complete system. This paper introduced the shortages of the existing test methods. A system-level test method of digital metering in smart substation was proposed, and the feasibility of the method was proved by the actual test.

Automated translating beam profiler for in situ laser beam spot-size and focal position measurements

NASA Astrophysics Data System (ADS)

Keaveney, James

2018-03-01

We present a simple and convenient, high-resolution solution for automated laser-beam profiling with axial translation. The device is based on a Raspberry Pi computer, Pi Noir CMOS camera, stepper motor, and commercial translation stage. We also provide software to run the device. The CMOS sensor is sensitive over a large wavelength range between 300 and 1100 nm and can be translated over 25 mm along the beam axis. The sensor head can be reversed without changing its axial position, allowing for a quantitative estimate of beam overlap with counter-propagating laser beams. Although not limited to this application, the intended use for this device is the automated measurement of the focal position and spot-size of a Gaussian laser beam. We present example data of one such measurement to illustrate device performance.

Automated translating beam profiler for in situ laser beam spot-size and focal position measurements.

PubMed

Keaveney, James

2018-03-01

We present a simple and convenient, high-resolution solution for automated laser-beam profiling with axial translation. The device is based on a Raspberry Pi computer, Pi Noir CMOS camera, stepper motor, and commercial translation stage. We also provide software to run the device. The CMOS sensor is sensitive over a large wavelength range between 300 and 1100 nm and can be translated over 25 mm along the beam axis. The sensor head can be reversed without changing its axial position, allowing for a quantitative estimate of beam overlap with counter-propagating laser beams. Although not limited to this application, the intended use for this device is the automated measurement of the focal position and spot-size of a Gaussian laser beam. We present example data of one such measurement to illustrate device performance.

Periprocedural intracardiac echocardiography for left atrial appendage closure: a dual-center experience.

PubMed

Berti, Sergio; Paradossi, Umberto; Meucci, Francesco; Trianni, Giuseppe; Tzikas, Apostolos; Rezzaghi, Marco; Stolkova, Miroslava; Palmieri, Cataldo; Mori, Fabio; Santoro, Gennaro

2014-09-01

This dual-center study sought to demonstrate the utility and safety of intracardiac echocardiography (ICE) in providing adequate imaging guidance as an alternative to transesophageal echocardiography (TEE) during Amplatzer Cardiac Plug device implantation. Over 90% of intracardiac thrombi in atrial fibrillation originate from the left atrial appendage (LAA). Patients with contraindications to anticoagulation are potential candidates for LAA percutaneous occlusion. TEE is typically used to guide implantation. ICE-guided percutaneous LAA closure was performed in 121 patients to evaluate the following tasks typically achieved by TEE: assessment of the LAA dimension for device sizing; guidance of transseptal puncture; verification of the delivery sheath position; confirmation of location and stability of the device before and after release and continuous monitoring to detect procedural complications. In 51 consecutive patients, we compared the measurements obtained by ICE and fluoroscopy to choose the size of the device. The device was successfully implanted in 117 patients, yielding a technical success rate of 96.7%. Procedural success was achieved in 113 cases (93.4%). Four major adverse events (3 cardiac tamponades and 1 in-hospital transient ischemic attack) occurred. There was significant correlation in the measurements for device sizing assessed by angiography and ICE (r = 0.94, p < 0.0001). ICE imaging was able to perform the tasks typically provided by TEE during implantation of the Amplatzer Cardiac Plug device for LAA occlusion. Therefore, we provide evidence that the use of ICE offered accurate measurements of LAA dimension in order to select the correct device sizes. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

PubMed

Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

2016-01-01

Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices

PubMed Central

Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

2016-01-01

Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information. PMID:27907188

Modulation characteristics of graphene-based thermal emitters

NASA Astrophysics Data System (ADS)

Mahlmeister, Nathan Howard; Lawton, Lorreta Maria; Luxmoore, Isaac John; Nash, Geoffrey Richard

2016-01-01

We have investigated the modulation characteristics of the emission from a graphene-based thermal emitter both experimentally and through simulations using finite element method modelling. Measurements were performed on devices containing square multilayer graphene emitting areas, with the devices driven by a pulsed DC drive current over a range of frequencies. Simulations show that the dominant heat path is from the emitter to the underlying substrate, and that the thermal resistance between the graphene and the substrate determines the modulation characteristics. This is confirmed by measurements made on devices in which the emitting area is encapsulated by hexagonal boron nitride.

Biased decoy-state measurement-device-independent quantum cryptographic conferencing with finite resources.

PubMed

Chen, RuiKe; Bao, WanSu; Zhou, Chun; Li, Hongwei; Wang, Yang; Bao, HaiZe

2016-03-21

In recent years, a large quantity of work have been done to narrow the gap between theory and practice in quantum key distribution (QKD). However, most of them are focus on two-party protocols. Very recently, Yao Fu et al proposed a measurement-device-independent quantum cryptographic conferencing (MDI-QCC) protocol and proved its security in the limit of infinitely long keys. As a step towards practical application for MDI-QCC, we design a biased decoy-state measurement-device-independent quantum cryptographic conferencing protocol and analyze the performance of the protocol in both the finite-key and infinite-key regime. From numerical simulations, we show that our decoy-state analysis is tighter than Yao Fu et al. That is, we can achieve the nonzero asymptotic secret key rate in long distance with approximate to 200km and we also demonstrate that with a finite size of data (say 10¹¹ to 10¹³ signals) it is possible to perform secure MDI-QCC over reasonable distances.

Investigating fast enzyme-DNA kinetics using multidimensional fluorescence imaging and microfluidics

NASA Astrophysics Data System (ADS)

Robinson, Tom; Manning, Hugh B.; Dunsby, Christopher; Neil, Mark A. A.; Baldwin, Geoff S.; de Mello, Andrew J.; French, Paul M. W.

2010-02-01

We have developed a rapid microfluidic mixing device to image fast kinetics. To verify the performance of the device it was simulated using computational fluid dynamics (CFD) and the results were directly compared to experimental fluorescence lifetime imaging (FLIM) measurements. The theoretical and measured mixing times of the device were found to be in agreement over a range of flow rates. This mixing device is being developed with the aim of analysing fast enzyme kinetics in the sub-millisecond time domain, which cannot be achieved with conventional macro-stopped flow devices. Here we have studied the binding of a DNA repair enzyme, uracil DNA glycosylase (UDG), to a fluorescently labelled DNA substrate. Bulk phase fluorescence measurements have been used to measure changes on binding: it was found that the fluorescence lifetime increased along with an increase in the polarisation anisotropy and rotational correlation time. Analysis of the same reaction in the microfluidic mixer by CFD enabled us to predict the mixing time of the device to be 46 μs, more than 20 times faster than current stopped-flow techniques. We also demonstrate that it is possible to image UDG-DNA interactions within the micromixer using the signal changes observed from the multidimensional spectrofluorometer.

Pilot study of methods and equipment for in-home noise level measurements.

PubMed

Neitzel, Richard L; Heikkinen, Maire S A; Williams, Christopher C; Viet, Susan Marie; Dellarco, Michael

2015-01-15

Knowledge of the auditory and non-auditory effects of noise has increased dramatically over the past decade, but indoor noise exposure measurement methods have not advanced appreciably, despite the introduction of applicable new technologies. This study evaluated various conventional and smart devices for exposure assessment in the National Children's Study. Three devices were tested: a sound level meter (SLM), a dosimeter, and a smart device with a noise measurement application installed. Instrument performance was evaluated in a series of semi-controlled tests in office environments over 96-hour periods, followed by measurements made continuously in two rooms (a child's bedroom and a most used room) in nine participating homes over a 7-day period with subsequent computation of a range of noise metrics. The SLMs and dosimeters yielded similar A-weighted average noise levels. Levels measured by the smart devices often differed substantially (showing both positive and negative bias, depending on the metric) from those measured via SLM and dosimeter, and demonstrated attenuation in some frequency bands in spectral analysis compared to SLM results. Virtually all measurements exceeded the Environmental Protection Agency's 45 dBA day-night limit for indoor residential exposures. The measurement protocol developed here can be employed in homes, demonstrates the possibility of measuring long-term noise exposures in homes with technologies beyond traditional SLMs, and highlights potential pitfalls associated with measurements made by smart devices.

Calibration procedure for a laser triangulation scanner with uncertainty evaluation

NASA Astrophysics Data System (ADS)

Genta, Gianfranco; Minetola, Paolo; Barbato, Giulio

2016-11-01

Most of low cost 3D scanning devices that are nowadays available on the market are sold without a user calibration procedure to correct measurement errors related to changes in environmental conditions. In addition, there is no specific international standard defining a procedure to check the performance of a 3D scanner along time. This paper aims at detailing a thorough methodology to calibrate a 3D scanner and assess its measurement uncertainty. The proposed procedure is based on the use of a reference ball plate and applied to a triangulation laser scanner. Experimental results show that the metrological performance of the instrument can be greatly improved by the application of the calibration procedure that corrects systematic errors and reduces the device's measurement uncertainty.

Metrological characterization of 3D imaging devices

NASA Astrophysics Data System (ADS)

Guidi, G.

2013-04-01

Manufacturers often express the performance of a 3D imaging device in various non-uniform ways for the lack of internationally recognized standard requirements for metrological parameters able to identify the capability of capturing a real scene. For this reason several national and international organizations in the last ten years have been developing protocols for verifying such performance. Ranging from VDI/VDE 2634, published by the Association of German Engineers and oriented to the world of mechanical 3D measurements (triangulation-based devices), to the ASTM technical committee E57, working also on laser systems based on direct range detection (TOF, Phase Shift, FM-CW, flash LADAR), this paper shows the state of the art about the characterization of active range devices, with special emphasis on measurement uncertainty, accuracy and resolution. Most of these protocols are based on special objects whose shape and size are certified with a known level of accuracy. By capturing the 3D shape of such objects with a range device, a comparison between the measured points and the theoretical shape they should represent is possible. The actual deviations can be directly analyzed or some derived parameters can be obtained (e.g. angles between planes, distances between barycenters of spheres rigidly connected, frequency domain parameters, etc.). This paper shows theoretical aspects and experimental results of some novel characterization methods applied to different categories of active 3D imaging devices based on both principles of triangulation and direct range detection.

A clip-free eyeglasses-based wearable monitoring device for measuring photoplethysmograhic signals.

PubMed

Zheng, Yali; Leung, Billy; Sy, Stanley; Zhang, Yuanting; Poon, Carmen C Y

2012-01-01

An eyeglasses-based device has been developed in this work to acquire photoplethysmogram (PPG) from the nose bridge. This device is aimed to provide wearable physiological monitoring without uncomfortable clips frequently used in PPG measurement from finger and ear. Switching control is applied on the LED and photo detector for power saving. An experiment involving postural change and treadmill jogging among 10 healthy young subjects was carried out to evaluate the performance of the device. Electrocardiogram (ECG) and PPG from finger, ear and nose were simultaneously recorded, from which heart rate (HR) and pulse transit time (PTT) were calculated. The results show that PPG measured from nose and ear are more resistant to motion than signal from finger during exercise. In addition, the difference between PTT measured from ear and nose indicates that local vasomotor activities may exist on ear and/or nose channel, and suggests that PPG from different sites should be used for cuff-less PTT-based BP estimation. We conclude that this wearable device has great potential to be used in the healthcare management in the future.

Electro-optical characterization of GaAs solar cells

NASA Technical Reports Server (NTRS)

Olsen, Larry C.; Dunham, Glen; Addis, F. W.; Huber, Dan; Daling, Dave

1987-01-01

The electro-optical characterization of gallium arsenide p/n solar cells is discussed. The objective is to identify and understand basic mechanisms which limit the performance of high efficiency gallium arsenide solar cells. The approach involves conducting photoresponse and temperature dependent current-voltage measurements, and interpretation of the data in terms of theory to determine key device parameters. Depth concentration profiles are also utilized in formulating a model to explain device performance.

Infrared charge-injection-device array performance at low background

NASA Technical Reports Server (NTRS)

Mccreight, C. R.; Goebel, J. H.

1981-01-01

Low-background tests of a 1 x 32 Si:Bi charge-injection-device (CID) IR detector are carried out to evaluate its feasibility for space-based astronomical observations. Optimum performance is obtained at a temperature of 11 K. The sensitivity is found to compare well with that of discrete extrinsic silicon photoconductors. The measured sensitivity and the apparent absence of anomalous effects make extrinsic silicon CID arrays very promising for astronomical applications.

Inertial Properties of an External-Frame Backpack Device

DTIC Science & Technology

2003-04-10

for designers (NASA Reference Publication 1024) (pp. IV-l-IV- 76). Yellow Springs, OH: Anthropology Research Project. Serway , R.A. (1990), Physics for...for use in studying the effects of the weight carried and the distribution of the weight on the physical performance of soldiers. The backpack was...soldier’s health and ability to perform physical activities, we thought it important to measure the MOI of the backpack device in the nine different

Flow Control and Measurement in Electric Propulsion Systems: Towards an AIAA Reference Standard

DTIC Science & Technology

2013-10-01

the spacecraft sensors, although some improvement can be made by averaging several measurements together. 3. Thermal Mass Gauging Thermal Mass...flow controllers (MFCs) to measure and control propellant into EP devices. To determine several key thruster performance parameters with a low level...the specified time interval may not be known. A first recourse is to perform several measurements and examine the linearity. In cases where the

Use of Mobile Device Accelerometry to Enhance Evaluation of Postural Instability in Parkinson Disease.

PubMed

Ozinga, Sarah J; Linder, Susan M; Alberts, Jay L

2017-04-01

To determine the accuracy of inertial measurement unit data from a mobile device using the mobile device relative to posturography to quantify postural stability in individuals with Parkinson disease (PD). Criterion standard. Motor control laboratory at a clinic. A sample (N=28) of individuals with mild to moderate PD (n=14) and age-matched community-dwelling individuals without PD (n=14) completed the study. Not applicable. Center of mass (COM) acceleration measures were compared between the mobile device and the NeuroCom force platform to determine the accuracy of mobile device measurements during performance of the Sensory Organization Test (SOT). Analyses examined test-retest reliability of both systems and sensitivity of (1) the equilibrium score from the SOT and (2) COM acceleration measures from the force platform and mobile device to quantify postural stability across populations. Metrics of COM acceleration from inertial measurement unit data and the NeuroCom force platform were significantly correlated across balance conditions and groups (Pearson r range, .35 to .97). The SOT equilibrium scores failed to discriminate individuals with and without PD. However, the multiplanar measures of COM acceleration from the mobile device exhibited good to excellent reliability across SOT conditions and were able to discriminate individuals with and without PD in conditions with the greatest balance demands. Metrics employing medial-lateral movement produce a more sensitive outcome than the equilibrium score in identifying postural instability associated with PD. Overall, the output from the mobile device provides an accurate and reliable method of rapidly quantifying balance in individuals with PD. The portable and affordable nature of a mobile device with the application makes it ideally suited to use biomechanical data to aid in clinical decision making. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Reliability of intraventricular pressure measurement with fiberoptic or solid-state transducers: avoidance of a methodological error.

PubMed

Raabe, A; Stöckel, R; Hohrein, D; Schöche, J

1998-01-01

The failure of intraventricular pressure measurement in cases of catheter blockage or dislodgement is thought to be eliminated by using intraventricular microtransducers. We report on an avoidable methodological error that may affect the reliability of intraventricular pressure measurement with these devices. Intraventricular fiberoptic or solid-state devices were implanted in 43 patients considered to be at risk for developing catheter occlusion. Two different types were used, i.e., devices in which the transducer is placed inside the ventriculostomy catheter (Type A) and devices in which the transducer is integrated in the external surface of the catheter (Type B). Type A devices were used in 15 patients and Type B devices in 28 patients. Pressure recordings were checked at bedside for the validity and reliability of the measurement. Of the 15 patients treated with Type A devices, no reliable pressure recordings were able to be obtained in three patients in whom ventricular punctures were not successful. In 4 of the remaining 12 patients, periods of erroneous pressure readings were detected. After opening of cerebrospinal fluid drainage, all Type A devices failed to reflect real intraventricular pressure. In patients treated with Type B devices, no erroneous pressure recordings were able to be identified, irrespective of whether cerebrospinal fluid drainage was performed. Even when ventricular puncture failed, pressure measurement was correct each time. Transducers that are simply placed inside the ventriculostomy catheter require fluid-coupling. They may fail, either during cerebrospinal fluid drainage or when the catheter is blocked or placed within the parenchyma.

Temperature Effects in Varactors and Multipliers

NASA Technical Reports Server (NTRS)

East, J.; Mehdi, Imran

2001-01-01

Varactor diode multipliers are a critical part of many THz measurement systems. The power and efficiencies of these devices limit the available power for THz sources. Varactor operation is determined by the physics of the varactor device and a careful doping profile design is needed to optimize the performance. Higher doped devices are limited by junction breakdown and lower doped structures are limited by current saturation. Higher doped structures typically have higher efficiencies and lower doped structures typically have higher powers at the same operating frequency and impedance level. However, the device material properties are also a function of the operating temperature. Recent experimental evidence has shown that the power output of a multiplier can be improved by cooling the device. We have used a particle Monte Carlo simulation to investigate the temperature dependent velocity vs. electric field in GaAs. This information was then included in a nonlinear device circuit simulator to predict multiplier performance for various temperatures and device designs. This paper will describe the results of this analysis of temperature dependent multiplier operation.

Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO{sub 2}) thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nordin, N.; Azizah, N.; Hashim, U., E-mail: uda@unimap.edu.my

2016-07-06

Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO{sub 2}) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM.more » Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.« less

A cost-effective measurement-device-independent quantum key distribution system for quantum networks

NASA Astrophysics Data System (ADS)

Valivarthi, Raju; Zhou, Qiang; John, Caleb; Marsili, Francesco; Verma, Varun B.; Shaw, Matthew D.; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

2017-12-01

We experimentally realize a measurement-device-independent quantum key distribution (MDI-QKD) system. It is based on cost-effective and commercially available hardware such as distributed feedback lasers and field-programmable gate arrays that enable time-bin qubit preparation and time-tagging, and active feedback systems that allow for compensation of time-varying properties of photons after transmission through deployed fiber. We examine the performance of our system, and conclude that its design does not compromise performance. Our demonstration paves the way for MDI-QKD-based quantum networks in star-type topology that extend over more than 100 km distance.

Device-independent randomness generation from several Bell estimators

NASA Astrophysics Data System (ADS)

Nieto-Silleras, Olmo; Bamps, Cédric; Silman, Jonathan; Pironio, Stefano

2018-02-01

Device-independent randomness generation and quantum key distribution protocols rely on a fundamental relation between the non-locality of quantum theory and its random character. This relation is usually expressed in terms of a trade-off between the probability of guessing correctly the outcomes of measurements performed on quantum systems and the amount of violation of a given Bell inequality. However, a more accurate assessment of the randomness produced in Bell experiments can be obtained if the value of several Bell expressions is simultaneously taken into account, or if the full set of probabilities characterizing the behavior of the device is considered. We introduce protocols for device-independent randomness generation secure against classical side information, that rely on the estimation of an arbitrary number of Bell expressions or even directly on the experimental frequencies of measurement outcomes. Asymptotically, this results in an optimal generation of randomness from experimental data (as measured by the min-entropy), without having to assume beforehand that the devices violate a specific Bell inequality.

Challenges in standardization of blood pressure measurement at the population level.

PubMed

Tolonen, Hanna; Koponen, Päivikki; Naska, Androniki; Männistö, Satu; Broda, Grazyna; Palosaari, Tarja; Kuulasmaa, Kari

2015-04-10

Accurate blood pressure measurements are needed in clinical practice, intervention studies and health examination surveys. Blood pressure measurements are sensitive: their accuracy can be affected by measurement environment, behaviour of the subject, measurement procedures, devices used for the measurement and the observer. To minimize errors in blood pressure measurement, a standardized measurement protocol is needed. The European Health Examination Survey (EHES) Pilot project was conducted in 2009-2012. A pilot health examination survey was conducted in 12 countries using a standardized protocol. The measurement protocols used in each survey, training provided for the measurers, measurement data, and observations during site visits were collected and evaluated to assess the level of standardization. The EHES measurement protocol for blood pressure was followed accurately in all 12 pilot surveys. Most of the surveys succeeded in organizing a quiet and comfortable measurement environment, and staff instructed survey participants appropriately before examination visits. In all surveys, blood pressure was measured three times, from the right arm in a sitting posture. The biggest variation was in the device used for the blood pressure measurement. It is possible to reach a high level of standardization for blood pressure measurements across countries and over time. A detailed, standardized measurement protocol, and adequate training and monitoring during the fieldwork and centrally organized quality assessment of the data are needed. The recent EU regulation banning the sale of mercury sphygmomanometer in European Union Member States has set new challenges for the standardization of measurement devices since the validity of oscillometric measurements is device-specific and performance of aneroid devices depends very much on calibration.

Constructing experimental devices for half-ton synthesis of gadolinium-loaded liquid scintillator and its performance.

PubMed

Park, Young Seo; Jang, Yeong Min; Joo, Kyung Kwang

2018-04-01

This paper describes in brief features of various experimental devices constructed for half-ton synthesis of gadolinium(Gd)-loaded liquid scintillator (GdLS) and also includes the performances and detailed chemical and physical results of a 0.5% high-concentration GdLS. Various feasibility studies on useful apparatus used for loading Gd into solvents have been carried out. The transmittance, Gd concentration, density, light yield, and moisture content were measured for quality control. We show that with the help of adequate automated experimental devices and tools, it is possible to perform ton scale synthesis of GdLS at moderate laboratory scale without difficulty. The synthesized GdLS was satisfactory to meet chemical, optical, and physical properties and various safety requirements. These synthesizing devices can be expanded into massive scale next-generation neutrino experiments of several hundred tons.

Enhanced thermoelectric performance of graphene nanoribbon-based devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hossain, Md Sharafat, E-mail: hossain@student.unimelb.edu.au; Huynh, Duc Hau; Nguyen, Phuong Duc

There have been numerous theoretical studies on exciting thermoelectric properties of graphene nano-ribbons (GNRs); however, most of these studies are mainly based on simulations. In this work, we measure and characterize the thermoelectric properties of GNRs and compare the results with theoretical predictions. Our experimental results verify that nano-structuring and patterning graphene into nano-ribbons significantly enhance its thermoelectric power, confirming previous predictions. Although patterning results in lower conductance (G), the overall power factor (S{sup 2}G) increases for nanoribbons. We demonstrate that edge roughness plays an important role in achieving such an enhanced performance and support it through first principles simulations.more » We show that uncontrolled edge roughness, which is considered detrimental in GNR-based electronic devices, leads to enhanced thermoelectric performance of GNR-based thermoelectric devices. The result validates previously reported theoretical studies of GNRs and demonstrates the potential of GNRs for the realization of highly efficient thermoelectric devices.« less

Constructing experimental devices for half-ton synthesis of gadolinium-loaded liquid scintillator and its performance

NASA Astrophysics Data System (ADS)

Park, Young Seo; Jang, Yeong Min; Joo, Kyung Kwang

2018-04-01

This paper describes in brief features of various experimental devices constructed for half-ton synthesis of gadolinium(Gd)-loaded liquid scintillator (GdLS) and also includes the performances and detailed chemical and physical results of a 0.5% high-concentration GdLS. Various feasibility studies on useful apparatus used for loading Gd into solvents have been carried out. The transmittance, Gd concentration, density, light yield, and moisture content were measured for quality control. We show that with the help of adequate automated experimental devices and tools, it is possible to perform ton scale synthesis of GdLS at moderate laboratory scale without difficulty. The synthesized GdLS was satisfactory to meet chemical, optical, and physical properties and various safety requirements. These synthesizing devices can be expanded into massive scale next-generation neutrino experiments of several hundred tons.

Accuracy of a new partial coherence interferometry analyser for biometric measurements.

PubMed

Holzer, M P; Mamusa, M; Auffarth, G U

2009-06-01

Precise biometry is an essential preoperative measurement for refractive surgery as well as cataract surgery. A new device based on partial coherence interferometry technology was tested and evaluated for accuracy of measurements. In a prospective study 200 eyes of 100 healthy phakic volunteers were examined with a functional prototype of the new ALLEGRO BioGraph (Wavelight AG)/LENSTAR LS 900 (Haag Streit AG) biometer and with the IOLMaster V.5 (Carl Zeiss Meditec AG). As recommended by the manufacturers, repeated measurements were performed with both devices and the results compared using Spearman correlation calculations (WinSTAT). Spearman correlation showed high correlations for axial length and keratometry measurements between the two devices tested. Anterior chamber depth, however, had a lower correlation between the two biometry devices. In addition, the mean values of the anterior chamber depth differed (IOLMaster 3.48 (SD 0.42) mm versus BioGraph/LENSTAR 3.64 (SD 0.26) mm); however, this difference was not statistically different (p>0.05, t test). The new biometer provided results that correlated very well with those of the IOLMaster. The ALLEGRO BioGraph/LENSTAR LS 900 is a precise device containing additional features that will be helpful tools for any cataract or refractive surgeon.

Imaging performance of a normal incidence soft X-ray telescope

NASA Technical Reports Server (NTRS)

Henry, J. P.; Spiller, E.; Weisskopf, M.

1982-01-01

Measurements are presented of the imaging performance of a normal incidence spherical soft X-ray mirror at BK-alpha (67.6 A). The reflector was a 124-layer coating consisting of alternating Re-W alloy and C layers with a protective C overcoat 34 A thick deposited on a Zerodur substrate. Measurements made at an angle of 1.5 deg off axis with the prototype of the Einstein Observatory high resolution imager reveal the resolution of the mirror to be about 1 arcsec FWHM, with 50% of the reflected power within the detector field of 512 arcsec contained within a diameter of 5 arcsec. The data demonstrate the practicality and potential good performance of normal-incidence soft X-ray optics, and show that the scattering performances of such devices may be as good or better than the best grazing incidence devices.

Testing of mechanical ventilators and infant incubators in healthcare institutions.

PubMed

Badnjevic, Almir; Gurbeta, Lejla; Jimenez, Elvira Ruiz; Iadanza, Ernesto

2017-01-01

The medical device industry has grown rapidly and incessantly over the past century. The sophistication and complexity of the designed instrumentation is nowadays rising and, with it, has also increased the need to develop some better, more effective and efficient maintenance processes, as part of the safety and performance requirements. This paper presents the results of performance tests conducted on 50 mechanical ventilators and 50 infant incubators used in various public healthcare institutions. Testing was conducted in accordance to safety and performance requirements stated in relevant international standards, directives and legal metrology policies. Testing of output parameters for mechanical ventilators was performed in 4 measuring points while testing of output parameters for infant incubators was performed in 7 measuring points for each infant incubator. As performance criteria, relative error of output parameters for mechanical ventilators and absolute error of output parameters for infant incubators was calculated. The ranges of permissible error, for both groups of devices, are regulated by the Rules on Metrological and Technical Requirements published in the Official Gazette of Bosnia and Herzegovina No. 75/14, which are defined based on international recommendations, standards and guidelines. All ventilators and incubators were tested by etalons calibrated in an ISO 17025 accredited laboratory, which provides compliance to international standards for all measured parameters.The results show that 30% of the tested medical devices are not operating properly and should be serviced, recalibrated and/or removed from daily application.

A Comparison and Calibration of a Wrist-Worn Blood Pressure Monitor for Patient Management: Assessing the Reliability of Innovative Blood Pressure Devices

PubMed Central

Melville, Sarah; Teskey, Robert; Philip, Shona; Simpson, Jeremy A; Lutchmedial, Sohrab

2018-01-01

Background Clinical guidelines recommend monitoring of blood pressure at home using an automatic blood pressure device for the management of hypertension. Devices are not often calibrated against direct blood pressure measures, leaving health care providers and patients with less reliable information than is possible with current technology. Rigorous assessments of medical devices are necessary for establishing clinical utility. Objective The purpose of our study was 2-fold: (1) to assess the validity and perform iterative calibration of indirect blood pressure measurements by a noninvasive wrist cuff blood pressure device in direct comparison with simultaneously recorded peripheral and central intra-arterial blood pressure measurements and (2) to assess the validity of the measurements thereafter of the noninvasive wrist cuff blood pressure device in comparison with measurements by a noninvasive upper arm blood pressure device to the Canadian hypertension guidelines. Methods The cloud-based blood pressure algorithms for an oscillometric wrist cuff device were iteratively calibrated to direct pressure measures in 20 consented patient participants. We then assessed measurement validity of the device, using Bland-Altman analysis during routine cardiovascular catheterization. Results The precalibrated absolute mean difference between direct intra-arterial to wrist cuff pressure measurements were 10.8 (SD 9.7) for systolic and 16.1 (SD 6.3) for diastolic. The postcalibrated absolute mean difference was 7.2 (SD 5.1) for systolic and 4.3 (SD 3.3) for diastolic pressures. This is an improvement in accuracy of 33% systolic and 73% diastolic with a 48% reduction in the variability for both measures. Furthermore, the wrist cuff device demonstrated similar sensitivity in measuring high blood pressure compared with the direct intra-arterial method. The device, when calibrated to direct aortic pressures, demonstrated the potential to reduce a treatment gap in high blood pressure measurements. Conclusions The systolic pressure measurements of the wrist cuff have been iteratively calibrated using gold standard central (ascending aortic) pressure. This improves the accuracy of the indirect measures and potentially reduces the treatment gap. Devices that undergo auscultatory (indirect) calibration for licensing can be greatly improved by additional iterative calibration via intra-arterial (direct) measures of blood pressure. Further clinical trials with repeated use of the device over time are needed to assess the reliability of the device in accordance with current and evolving guidelines for informed decision making in the management of hypertension. Trial Registration ClinicalTrials.gov NCT03015363; https://clinicaltrials.gov/ct2/show/NCT03015363 (Archived by WebCite at http://www.webcitation.org/6xPZgseYS) PMID:29695375

[An implantable micro-device using wireless power transmission for measuring aortic aneurysm sac pressure].

PubMed

Guo, Xudong; Ge, Bin; Wang, Wenxing

2013-08-01

In order to detect endoleaks after endovascular aneurysm repair (EVAR), we developed an implantable micro-device based on wireless power transmission to measure aortic aneurysm sac pressure. The implantable micro-device is composed of a miniature wireless pressure sensor, an energy transmitting coil, a data recorder and a data processing platform. Power transmission without interconnecting wires is performed by a transmitting coil and a receiving coil. The coupling efficiency of wireless power transmission depends on the coupling coefficient between the transmitting coil and the receiving coil. With theoretical analysis and experimental study, we optimized the geometry of the receiving coil to increase the coupling coefficient. In order to keep efficiency balance and satisfy the maximizing conditions, we designed a closed loop power transmission circuit, including a receiving voltage feedback module based on wireless communication. The closed loop improved the stability and reliability of transmission energy. The prototype of the micro-device has been developed and the experiment has been performed. The experiments showed that the micro-device was feasible and valid. For normal operation, the distance between the transmitting coil and the receiving coil is smaller than 8cm. Besides, the distance between the micro-device and the data recorder is within 50cm.

Development and control of a magnetorheological haptic device for robot assisted surgery.

PubMed

Shokrollahi, Elnaz; Goldenberg, Andrew A; Drake, James M; Eastwood, Kyle W; Kang, Matthew

2017-07-01

A prototype magnetorheological (MR) fluid-based actuator has been designed for tele-robotic surgical applications. This device is capable of generating forces up to 47 N, with input currents ranging from 0 to 1.5 A. We begin by outlining the physical design of the device, and then discuss a novel nonlinear model of the device's behavior. The model was developed using the Hammerstein-Wiener (H-W) nonlinear black-box technique and is intended to accurately capture the hysteresis behavior of the MR-fluid. Several experiments were conducted on the device to collect estimation and validation datasets to construct the model and assess its performance. Different estimating functions were used to construct the model, and their effectiveness is assessed based on goodness-of-fit and final-prediction-error measurements. A sigmoid network was found to have a goodness-of-fit of 95%. The model estimate was then used to tune a PID controller. Two control schemes were proposed to eliminate the hysteresis behavior present in the MR fluid device. One method uses a traditional force feedback control loop and the other is based on measuring the magnetic field using a Hall-effect sensor embedded within the device. The Hall-effect sensor scheme was found to be superior in terms of cost, simplicity and real-time control performance compared to the force control strategy.

Backscattered electron simulations to evaluate sensitivity against electron dosage of buried semiconductor features

NASA Astrophysics Data System (ADS)

Mukhtar, Maseeh; Thiel, Bradley

2018-03-01

In fabrication, overlay measurements of semiconductor device patterns have conventionally been performed using optical methods. Beginning with image-based techniques using box-in-box to the more recent diffraction-based overlay (DBO). Alternatively, use of SEM overlay is under consideration for in-device overlay. Two main application spaces are measurement features from multiple mask levels on the same surface and buried features. Modern CD-SEMs are adept at measuring overlay for cases where all features are on the surface. In order to measure overlay of buried features, HV-SEM is needed. Gate-to-fin and BEOL overlay are important use cases for this technique. A JMONSEL simulation exercise was performed for these two cases using 10 nm line/space gratings of graduated increase in depth of burial. Backscattered energy loss results of these simulations were used to calculate the sensitivity measurements of buried features versus electron dosage for an array of electron beam voltages.

Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

DOEpatents

Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

2015-12-08

A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

Development of an electronic manometer for intrapleural pressure monitoring.

PubMed

Krenke, Rafał; Guć, Maciej; Grabczak, Elżbieta Magdalena; Michnikowski, Marcin; Pałko, Krzysztof Jakub; Chazan, Ryszarda; Gólczewski, Tomasz

2011-01-01

Measurement of intrapleural pressure is useful during various pleural procedures. However, a pleural manometer is rarely available. The aim of this study was to (1) construct an electronic pleural manometer, (2) assess the accuracy of the measurements done with the new device, (3) calculate the costs of the manometer construction and (4) perform an initial evaluation of the device in a clinical setting. Only widely accessible elements were used to construct the device. A vascular pressure transducer was used to transform pressure into an electronic signal. Reliability of the measurements was evaluated in a laboratory setting in a prospective, single-blind manner by comparing the results with those measured by a water manometer. Functionality of the device was assessed during therapeutic thoracentesis. The cost of the new pleural manometer was calculated. We built a small, portable device which can precisely measure intrapleural pressure. The measurement results showed very high agreement with those registered with a water manometer (r = 0.999; p < 0.001). The initial evaluation of the electronic manometer during therapeutic thoracentesis showed it was easy to use. The total time needed for 6 measurements after withdrawal of different volumes of pleural fluid in 1 patient did not exceed 6 min. The total cost of the device was calculated to be <2,000 EUR. In the face of very limited offer of commercially available pleural manometers, it is possible to successfully construct a self-made, reliable, electronic pleural manometer at modest costs. The device is easy to use and enables data display and storage in the personal computer. Copyright © 2011 S. Karger AG, Basel.

Comparative study of the retinal nerve fibre layer thickness performed with optical coherence tomography and GDx scanning laser polarimetry in patients with primary open-angle glaucoma.

PubMed

Wasyluk, Jaromir T; Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona

2012-03-01

We compared the parameters of retinal nerve fibre layer in patients with advanced glaucoma with the use of different OCT (Optical Coherence Tomograph) devices in relation to analogical measurements performed with GDx VCC (Nerve Fiber Analyzer with Variable Corneal Compensation) scanning laser polarimetry. Study subjects had advanced primary open-angle glaucoma, previously treated conservatively, diagnosed and confirmed by additional examinations (visual field, ophthalmoscopy of optic nerve, gonioscopy), A total of 10 patients were enrolled (9 women and 1 man), aged 18-70 years of age. Nineteen eyes with advanced glaucomatous neuropathy were examined. 1) Performing a threshold perimetry Octopus, G2 strategy and ophthalmoscopy of optic nerve to confirm the presence of advanced primary open-angle glaucoma; 2) performing a GDx VCC scanning laser polarimetry of retinal nerve fibre layer; 3) measuring the retinal nerve fibre layer thickness with 3 different optical coherence tomographs. The parameters of the retinal nerve fibre layer thickness are highly correlated between the GDx and OCT Stratus and 3D OCT-1000 devices in mean retinal nerve fibre layer thickness, retinal nerve fibre layer thickness in the upper sector, and correlation of NFI (GDx) with mean retinal nerve fibre layer thickness in OCT examinations. Absolute values of the retinal nerve fibre layer thickness (measured in µm) differ significantly between GDx and all OCT devices. Examination with OCT devices is a sensitive diagnostic method of glaucoma, with good correlation with the results of GDx scanning laser polarimetry of the patients.

Sternal skin conductance: a reasonable surrogate for hot flash measurement?

PubMed

Pachman, Deirdre R; Loprinzi, Charles L; Novotny, Paul J; Satele, Daniel V; Linquist, Breanna M; Wolf, Sherry; Barton, Debra L

2013-11-01

This study aims to examine the accuracy of a new sternal skin conductance (SSC) device in measuring hot flashes and to assess the acceptability of the device by women. Three small descriptive pilot studies were performed using two sequential prototypes of the SSC device developed by an engineering device company in the Midwest. The devices were worn either in a monitored setting for 24 hours or in an ambulatory setting for 5 weeks. During the study period, women recorded hot flashes in a prospective hot flash diary and answered questions about the acceptability of wearing the SSC device. The first prototype was not able to collect any analyzable skin conductance data owing to various malfunction issues, including poor conductance and battery failure. However, 16 women wore the device for 5 weeks and reported that wearing the device was acceptable, although 31% stated that it interfered with daily activities. Hot flash data from the second prototype revealed a 24% concordance rate between self-reported and device-recorded hot flashes. Findings from these studies support discordance between device-recorded and self-reported hot flashes. In addition, the studies reveal further limitations of SSC monitoring, including difficulties with data collection and lack of consistency in interpretation. Based on these results and other recent trials identifying issues with SSC methodology, it is time to find a better physiologic surrogate measure for hot flashes.

Accuracy of methemoglobin measurements: comparison of six different commercial devices and one manual method.

PubMed

Dötsch, J; Demirakça, S; Hahn, D; Katz, N; Kühl, P G; Rascher, W

1999-06-01

During nitric oxide inhalation, methemoglobinemia needs to be monitored. We compared six commercially available instruments and one manual method for methemoglobin measurements. In addition, we studied whether and to what degree methylene blue interferes with methemoglobin measurements. In vitro methodologic study. Research laboratory in a university hospital. Five healthy volunteers from whom red blood cells were obtained. Methemoglobinemia was generated in a red blood cell suspension by nitric oxide; methemoglobin was measured with six commercial instruments and one manual photometric method to calculate variation coefficients and to determine the differences between the devices. Methemoglobin was measured with and without the addition of methylene blue with two instruments. Measurements were performed immediately after the addition of methylene blue. All six commercially available instruments had variation coefficients of <0.1 at methemoglobin concentrations of 5%, whereas the manual photometric method did not reach a variation coefficient of <0.1 at 8% of methemoglobin. Apart from two devices that measured slightly but significantly higher methemoglobin levels, all instruments measured similar values of methemoglobin when the same samples were determined simultaneously. Higher concentrations of methylene blue (10, 40, 100 microM) reduced substantially the apparent concentrations of methemoglobin. Interference by methylene blue was most pronounced at low methemoglobin levels. With some limitations, all commercial instruments that were tested performed adequately for the monitoring of methemoglobinemia. Methylene blue interferes with the methemoglobin measurements in a dose-dependent manner.

Experimental evaluation of cooling efficiency of the high performance cooling device

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan

2016-06-01

This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

Efficiency improvements of offline metrology job creation

NASA Astrophysics Data System (ADS)

Zuniga, Victor J.; Carlson, Alan; Podlesny, John C.; Knutrud, Paul C.

1999-06-01

Progress of the first lot of a new design through the production line is watched very closely. All performance metrics, cycle-time, in-line measurement results and final electrical performance are critical. Rapid movement of this lot through the line has serious time-to-market implications. Having this material waiting at a metrology operation for an engineer to create a measurement job plan wastes valuable turnaround time. Further, efficient use of a metrology system is compromised by the time required to create and maintain these measurement job plans. Thus, having a method to develop metrology job plans prior to the actual running of the material through the manufacture area can significantly improve both cycle time and overall equipment efficiency. Motorola and Schlumberger have worked together to develop and test such a system. The Remote Job Generator (RJG) created job plans for new device sin a manufacturing process from an NT host or workstation, offline. This increases available system tim effort making production measurements, decreases turnaround time on job plan creation and editing, and improves consistency across job plans. Most importantly this allows job plans for new devices to be available before the first wafers of the device arrive at the tool for measurement. The software also includes a database manager which allows updates of existing job plans to incorporate measurement changes required by process changes or measurement optimization. This paper will review the result of productivity enhancements through the increased metrology utilization and decreased cycle time associated with the use of RJG. Finally, improvements in process control through better control of Job Plans across different devices and layers will be discussed.

Accuracy of Heart Rate Watches: Implications for Weight Management

PubMed Central

2016-01-01

Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

Accuracy of Heart Rate Watches: Implications for Weight Management.

PubMed

Wallen, Matthew P; Gomersall, Sjaan R; Keating, Shelley E; Wisløff, Ulrik; Coombes, Jeff S

2016-01-01

Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67-0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16-0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1-9%) but greater for energy expenditure (9-43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss.

Display device-adapted video quality-of-experience assessment

NASA Astrophysics Data System (ADS)

Rehman, Abdul; Zeng, Kai; Wang, Zhou

2015-03-01

Today's viewers consume video content from a variety of connected devices, including smart phones, tablets, notebooks, TVs, and PCs. This imposes significant challenges for managing video traffic efficiently to ensure an acceptable quality-of-experience (QoE) for the end users as the perceptual quality of video content strongly depends on the properties of the display device and the viewing conditions. State-of-the-art full-reference objective video quality assessment algorithms do not take into account the combined impact of display device properties, viewing conditions, and video resolution while performing video quality assessment. We performed a subjective study in order to understand the impact of aforementioned factors on perceptual video QoE. We also propose a full reference video QoE measure, named SSIMplus, that provides real-time prediction of the perceptual quality of a video based on human visual system behaviors, video content characteristics (such as spatial and temporal complexity, and video resolution), display device properties (such as screen size, resolution, and brightness), and viewing conditions (such as viewing distance and angle). Experimental results have shown that the proposed algorithm outperforms state-of-the-art video quality measures in terms of accuracy and speed.

Finite-key analysis for measurement-device-independent quantum key distribution.

PubMed

Curty, Marcos; Xu, Feihu; Cui, Wei; Lim, Charles Ci Wen; Tamaki, Kiyoshi; Lo, Hoi-Kwong

2014-04-29

Quantum key distribution promises unconditionally secure communications. However, as practical devices tend to deviate from their specifications, the security of some practical systems is no longer valid. In particular, an adversary can exploit imperfect detectors to learn a large part of the secret key, even though the security proof claims otherwise. Recently, a practical approach--measurement-device-independent quantum key distribution--has been proposed to solve this problem. However, so far its security has only been fully proven under the assumption that the legitimate users of the system have unlimited resources. Here we fill this gap and provide a rigorous security proof against general attacks in the finite-key regime. This is obtained by applying large deviation theory, specifically the Chernoff bound, to perform parameter estimation. For the first time we demonstrate the feasibility of long-distance implementations of measurement-device-independent quantum key distribution within a reasonable time frame of signal transmission.

Integration of Virtual Machine Technologies into Hastily Formed Networks in Support of Humanitarian Relief and Disaster Recovery Missions

DTIC Science & Technology

2011-12-01

and measures of effectiveness (MOE). New technologies that offer solid-state hard drives built into modular VDI devices known as appliances ...Joint Reconfigurable Vehicle LAN Local Area Network LOS Line of Sight LTE Long Term Evolution MB Megabyte MOP Measure of Performance MOE Measure ...re-usable measures of performance and measures of effectiveness (MOP and MOE) and evaluation procedures will be applied to this research. A

Precision Luminosity of LHC Proton-Proton Collisions at 13 TeV Using Hit Counting With TPX Pixel Devices

NASA Astrophysics Data System (ADS)

Sopczak, André; Ali, Babar; Asawatavonvanich, Thanawat; Begera, Jakub; Bergmann, Benedikt; Billoud, Thomas; Burian, Petr; Caicedo, Ivan; Caforio, Davide; Heijne, Erik; Janeček, Josef; Leroy, Claude; Mánek, Petr; Mochizuki, Kazuya; Mora, Yesid; Pacík, Josef; Papadatos, Costa; Platkevič, Michal; Polanský, Štěpán; Pospíšil, Stanislav; Suk, Michal; Svoboda, Zdeněk

2017-03-01

A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13-TeV proton-proton collisions in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analyzed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10-s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period.

Non-contact method for characterization of small size thermoelectric modules.

PubMed

Manno, Michael; Yang, Bao; Bar-Cohen, Avram

2015-08-01

Conventional techniques for characterization of thermoelectric performance require bringing measurement equipment into direct contact with the thermoelectric device, which is increasingly error prone as device size decreases. Therefore, the novel work presented here describes a non-contact technique, capable of accurately measuring the maximum ΔT and maximum heat pumping of mini to micro sized thin film thermoelectric coolers. The non-contact characterization method eliminates the measurement errors associated with using thermocouples and traditional heat flux sensors to test small samples and large heat fluxes. Using the non-contact approach, an infrared camera, rather than thermocouples, measures the temperature of the hot and cold sides of the device to determine the device ΔT and a laser is used to heat to the cold side of the thermoelectric module to characterize its heat pumping capacity. As a demonstration of the general applicability of the non-contact characterization technique, testing of a thin film thermoelectric module is presented and the results agree well with those published in the literature.

Development and assessment of a hand assist device: GRIPIT.

PubMed

Kim, Byungchul; In, Hyunki; Lee, Dae-Young; Cho, Kyu-Jin

2017-02-21

Although various hand assist devices have been commercialized for people with paralysis, they are somewhat limited in terms of tool fixation and device attachment method. Hand exoskeleton robots allow users to grasp a wider range of tools but are heavy, complicated, and bulky owing to the presence of numerous actuators and controllers. The GRIPIT hand assist device overcomes the limitations of both conventional devices and exoskeleton robots by providing improved tool fixation and device attachment in a lightweight and compact device. GRIPIT has been designed to assist tripod grasp for people with spinal cord injury because this grasp posture is frequently used in school and offices for such activities as writing and grasping small objects. The main development objective of GRIPIT is to assist users to grasp tools with their own hand using a lightweight, compact assistive device that is manually operated via a single wire. GRIPIT consists of only a glove, a wire, and a small structure that maintains tendon tension to permit a stable grasp. The tendon routing points are designed to apply force to the thumb, index finger, and middle finger to form a tripod grasp. A tension-maintenance structure sustains the grasp posture with appropriate tension. Following device development, four people with spinal cord injury were recruited to verify the writing performance of GRIPIT compared to the performance of a conventional penholder and handwriting. Writing was chosen as the assessment task because it requires a tripod grasp, which is one of the main performance objectives of GRIPIT. New assessment, which includes six different writing tasks, was devised to measure writing ability from various viewpoints including both qualitative and quantitative methods, while most conventional assessments include only qualitative methods or simple time measuring assessments. Appearance, portability, difficulty of wearing, difficulty of grasping the subject, writing sensation, fatigability, and legibility were measured to assess qualitative performance while writing various words and sentences. Results showed that GRIPIT is relatively complicated to wear and use compared to a conventional assist device but has advantages for writing sensation, fatigability, and legibility because it affords sufficient grasp force during writing. Two quantitative performance factors were assessed, accuracy of writing and solidity of writing. To assess accuracy of writing, we asked subjects to draw various figures under given conditions. To assess solidity of writing, pen tip force and the angle variation of the pen were measured. Quantitative evaluation results showed that GRIPIT helps users to write accurately without pen shakes even high force is applied on the pen. Qualitative and quantitative results were better when subjects used GRIPIT than when they used the conventional penholder, mainly because GRIPIT allowed them to exert a higher grasp force. Grasp force is important because disabled people cannot control their fingers and thus need to move their entire arm to write, while non-disabled people only need to move their fingers to write. The tension-maintenance structure developed for GRIPIT provides appropriate grasp force and moment balance on the user's hand, but the other writing method only fixes the pen using friction force or requires the user's arm to generate a grasp force.

Silicon device performance measurements to support temperature range enhancement

NASA Technical Reports Server (NTRS)

Johnson, R. Wayne; Askew, Ray; Bromstead, James; Weir, Bennett

1991-01-01

The results of the NPN bipolar transistor (BJT) (2N6023) breakdown voltage measurements were analyzed. Switching measurements were made on the NPN BJT, the insulated gate bipolar transistor (IGBT) (TA9796) and the N-channel metal oxide semiconductor field effect transistor (MOSFET) (RFH75N05E). Efforts were also made to build a H-bridge inverter. Also discussed are the plans that have been made to do life testing on the devices, to build an inductive switching test circuit and to build a dc/dc switched mode converter.

A generic approach for examining the effectiveness of traffic control devices in school zones.

PubMed

Zhao, Xiaohua; Li, Jiahui; Ding, Han; Zhang, Guohui; Rong, Jian

2015-09-01

The effectiveness and performance of traffic control devices in school zones have been impacted significantly by many factors, such as driver behavioral attributes, roadway geometric features, environmental characteristics, weather and visibility conditions, region-wide traffic regulations and policies, control modes, etc. When deploying traffic control devices in school zones, efforts are needed to clarify: (1) whether traffic control device installation is warranted; and (2) whether other device effectively complements this traffic control device and strengthens its effectiveness. In this study, a generic approach is developed to examine and evaluate the effectiveness of various traffic control devices deployed in school zones through driving simulator-based experiments. A Traffic Control Device Selection Model (TCDSM) is developed and two representative school zones are selected as the testbed in Beijing for driving simulation implementation to enhance its applicability. Statistical analyses are conducted to extract the knowledge from test data recorded by a driving simulator. Multiple measures of effectiveness (MOEs) are developed and adopted including average speed, relative speed difference, and standard deviation of acceleration for traffic control device performance quantification. The experimental tests and analysis results reveal that the appropriateness of the installation of certain traffic control devices can be statistically verified by TCDSM. The proposed approach provides a generic framework to assess traffic control device performance in school zones including experiment design, statistical formulation, data analysis, simulation model implementation, data interpretation, and recommendation development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Medical-device risk management and public safety: using cost-benefit as a measurement of effectiveness

NASA Astrophysics Data System (ADS)

Hughes, Allen A.

1994-12-01

Public safety can be enhanced through the development of a comprehensive medical device risk management. This can be accomplished through case studies using a framework that incorporates cost-benefit analysis in the evaluation of risk management attributes. This paper presents a framework for evaluating the risk management system for regulatory Class III medical devices. The framework consists of the following sixteen attributes of a comprehensive medical device risk management system: fault/failure analysis, premarket testing/clinical trials, post-approval studies, manufacturer sponsored hospital studies, product labeling, establishment inspections, problem reporting program, mandatory hospital reporting, medical literature surveillance, device/patient registries, device performance monitoring, returned product analysis, autopsy program, emergency treatment funds/interim compensation, product liability, and alternative compensation mechanisms. Review of performance histories for several medical devices can reveal the value of information for many attributes, and also the inter-dependencies of the attributes in generating risk information flow. Such an information flow network is presented as a starting point for enhancing medical device risk management by focusing on attributes with high net benefit values and potential to spur information dissemination.

A New Cuffless Device for Measuring Blood Pressure: A Real-Life Validation Study

PubMed Central

Schoot, Tessa S; Weenk, Mariska; van de Belt, Tom H; Engelen, Lucien JLPG; van Goor, Harry

2016-01-01

Background Cuffless blood pressure (BP) monitoring devices, based on pulse transit time, are being developed as an easy-to-use, more convenient, fast, and relatively cheap alternative to conventional BP measuring devices based on cuff occlusion. Thereby they may provide a great alternative to BP self-measurement. Objective The objective of our study was to evaluate the performance of the first release of the Checkme Health Monitor (Viatom Technology), a cuffless BP monitor, in a real-life setting. Furthermore, we wanted to investigate whether the posture of the volunteer and the position of the device relative to the heart level would influence its outcomes. Methods Study volunteers fell into 3 BP ranges: high (>160 mmHg), normal (130–160 mmHg), and low (<130 mmHg). All requirements for test environment, observer qualification, volunteer recruitment, and BP measurements were met according to the European Society of Hypertension International Protocol (ESH-IP) for the validation of BP measurement devices. After calibrating the Checkme device, we measured systolic BP with Checkme and a validated, oscillometric reference BP monitor (RM). Measurements were performed in randomized order both in supine and in sitting position, and with Checkme at and above heart level. Results We recruited 52 volunteers, of whom we excluded 15 (12 due to calibration failure with Checkme, 3 due to a variety of reasons). The remaining 37 volunteers were divided into low (n=14), medium (n=13), and high (n=10) BP ranges. There were 18 men and 19 women, with a mean age of 54.1 (SD 14.5) years, and mean recruitment systolic BP of 141.7 (SD 24.7) mmHg. BP results obtained by RM and Checkme correlated well. In the supine position, the difference between the RM and Checkme was >5 mmHg in 17 of 37 volunteers (46%), of whom 9 of 37 (24%) had a difference >10 mmHg and 5 of 37 (14%) had a difference >15 mmHg. Conclusions BP obtained with Checkme correlated well with RM BP, particularly in the position (supine) in which the device was calibrated. These preliminary results are promising for conducting further research on cuffless BP measurement in the clinical and outpatient settings. PMID:27150527

On the tip of the tongue: learning typing and pointing with an intra-oral computer interface.

PubMed

Caltenco, Héctor A; Breidegard, Björn; Struijk, Lotte N S Andreasen

2014-07-01

To evaluate typing and pointing performance and improvement over time of four able-bodied participants using an intra-oral tongue-computer interface for computer control. A physically disabled individual may lack the ability to efficiently control standard computer input devices. There have been several efforts to produce and evaluate interfaces that provide individuals with physical disabilities the possibility to control personal computers. Training with the intra-oral tongue-computer interface was performed by playing games over 18 sessions. Skill improvement was measured through typing and pointing exercises at the end of each training session. Typing throughput improved from averages of 2.36 to 5.43 correct words per minute. Pointing throughput improved from averages of 0.47 to 0.85 bits/s. Target tracking performance, measured as relative time on target, improved from averages of 36% to 47%. Path following throughput improved from averages of 0.31 to 0.83 bits/s and decreased to 0.53 bits/s with more difficult tasks. Learning curves support the notion that the tongue can rapidly learn novel motor tasks. Typing and pointing performance of the tongue-computer interface is comparable to performances of other proficient assistive devices, which makes the tongue a feasible input organ for computer control. Intra-oral computer interfaces could provide individuals with severe upper-limb mobility impairments the opportunity to control computers and automatic equipment. Typing and pointing performance of the tongue-computer interface is comparable to performances of other proficient assistive devices, but does not cause fatigue easily and might be invisible to other people, which is highly prioritized by assistive device users. Combination of visual and auditory feedback is vital for a good performance of an intra-oral computer interface and helps to reduce involuntary or erroneous activations.

Haptic force-feedback devices for the office computer: performance and musculoskeletal loading issues.

PubMed

Dennerlein, J T; Yang, M C

2001-01-01

Pointing devices, essential input tools for the graphical user interface (GUI) of desktop computers, require precise motor control and dexterity to use. Haptic force-feedback devices provide the human operator with tactile cues, adding the sense of touch to existing visual and auditory interfaces. However, the performance enhancements, comfort, and possible musculoskeletal loading of using a force-feedback device in an office environment are unknown. Hypothesizing that the time to perform a task and the self-reported pain and discomfort of the task improve with the addition of force feedback, 26 people ranging in age from 22 to 44 years performed a point-and-click task 540 times with and without an attractive force field surrounding the desired target. The point-and-click movements were approximately 25% faster with the addition of force feedback (paired t-tests, p < 0.001). Perceived user discomfort and pain, as measured through a questionnaire, were also smaller with the addition of force feedback (p < 0.001). However, this difference decreased as additional distracting force fields were added to the task environment, simulating a more realistic work situation. These results suggest that for a given task, use of a force-feedback device improves performance, and potentially reduces musculoskeletal loading during mouse use. Actual or potential applications of this research include human-computer interface design, specifically that of the pointing device extensively used for the graphical user interface.

Assessment of body-powered upper limb prostheses by able-bodied subjects, using the Box and Blocks Test and the Nine-Hole Peg Test.

PubMed

Haverkate, Liz; Smit, Gerwin; Plettenburg, Dick H

2016-02-01

The functional performance of currently available body-powered prostheses is unknown. The goal of this study was to objectively assess and compare the functional performance of three commonly used body-powered upper limb terminal devices. Experimental trial. A total of 21 able-bodied subjects (n = 21, age = 22 ± 2) tested three different terminal devices: TRS voluntary closing Hook Grip 2S, Otto Bock voluntary opening hand and Hosmer Model 5XA hook, using a prosthesis simulator. All subjects used each terminal device nine times in two functional tests: the Nine-Hole Peg Test and the Box and Blocks Test. Significant differences were found between the different terminal devices and their scores on the Nine-Hole Peg Test and the Box and Blocks Test. The Hosmer hook scored best in both tests. The TRS Hook Grip 2S scored second best. The Otto Bock hand showed the lowest scores. This study is a first step in the comparison of functional performances of body-powered prostheses. The data can be used as a reference value, to assess the performance of a terminal device or an amputee. The measured scores enable the comparison of the performance of a prosthesis user and his or her terminal device relative to standard scores. © The International Society for Prosthetics and Orthotics 2014.

Analytical and Experimental Performance Evaluation of BLE Neighbor Discovery Process Including Non-Idealities of Real Chipsets

PubMed Central

Perez-Diaz de Cerio, David; Hernández, Ángela; Valenzuela, Jose Luis; Valdovinos, Antonio

2017-01-01

The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE) as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage. PMID:28273801

Analytical and Experimental Performance Evaluation of BLE Neighbor Discovery Process Including Non-Idealities of Real Chipsets.

PubMed

Perez-Diaz de Cerio, David; Hernández, Ángela; Valenzuela, Jose Luis; Valdovinos, Antonio

2017-03-03

The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE) as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage.

Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

NASA Technical Reports Server (NTRS)

Chervenak, J. A.; Adams, J. A.; Bandler, S. B.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.;

Experimental evaluation of a miniature MR device for a wide range of human perceivable haptic sensations

NASA Astrophysics Data System (ADS)

Yang, Tae-Heon; Koo, Jeong-Hoi

2017-12-01

Humans can experience a realistic and vivid haptic sensations by the sense of touch. In order to have a fully immersive haptic experience, both kinaesthetic and vibrotactile information must be presented to human users. Currently, little haptic research has been performed on small haptic actuators that can covey both vibrotactile feedback based on the frequency of vibrations up to the human-perceivable limit and multiple levels of kinaesthetic feedback rapidly. Therefore, this study intends to design a miniature haptic device based on MR fluid and experimentally evaluate its ability to convey vibrotactile feedback up to 300 Hz along with kinaesthetic feedback. After constructing a prototype device, a series of testing was performed to evaluate its performance of the prototype using an experimental setup, consisting of a precision dynamic mechanical analyzer and an accelerometer. The kinaesthetic testing results show that the prototype device can provide the force rate up to 89% at 5 V (360 mA), which can be discretized into multiple levels of ‘just noticeable difference’ force rate, indicating that the device can convey a wide range of kinaesthetic sensations. To evaluate the high frequency vibrotactile feedback performance of the device, its acceleration responses were measured and processed using the FFT analysis. The results indicate that the device can convey high frequency vibrotactile sensations up to 300 Hz with the sufficiently large intensity of accelerations that human can feel.

Accurate measurement of chest compression depth using impulse-radio ultra-wideband sensor on a mattress

PubMed Central

Kim, Yeomyung

2017-01-01

Objective We developed a new chest compression depth (CCD) measuring technology using radar and impulse-radio ultra-wideband (IR-UWB) sensor. This study was performed to determine its accuracy on a soft surface. Methods Four trials, trial 1: chest compressions on the floor using an accelerometer device; trial 2: chest compressions on the floor using an IR-UWB sensor; trial 3: chest compressions on a foam mattress using an accelerometer device; trial 4: chest compressions on a foam mattress using an IR-UWB sensor, were performed in a random order. In all the trials, a cardiopulmonary resuscitation provider delivered 50 uninterrupted chest compressions to a manikin. Results The CCD measured by the manikin and the device were as follows: 57.42 ± 2.23 and 53.92 ± 2.92 mm, respectively in trial 1 (p < 0.001); 56.29 ± 1.96 and 54.16 ± 3.90 mm, respectively in trial 2 (p < 0.001); 55.61 ± 1.57 and 103.48 ± 10.48 mm, respectively in trial 3 (p < 0.001); 57.14 ± 3.99 and 55.51 ± 3.39 mm, respectively in trial 4 (p = 0.012). The gaps between the CCD measured by the manikin and the devices (accelerometer device vs. IR-UWB sensor) on the floor were not different (3.50 ± 2.08 mm vs. 3.15 ± 2.27 mm, respectively, p = 0.136). However, the gaps were significantly different on the foam mattress (48.53 ± 5.65 mm vs. 4.10 ± 2.47 mm, p < 0.001). Conclusion The IR-UWB sensor could measure the CCD accurately both on the floor and on the foam mattress. PMID:28854262

Accurate measurement of chest compression depth using impulse-radio ultra-wideband sensor on a mattress.

PubMed

Yu, Byung Gyu; Oh, Je Hyeok; Kim, Yeomyung; Kim, Tae Wook

2017-01-01

We developed a new chest compression depth (CCD) measuring technology using radar and impulse-radio ultra-wideband (IR-UWB) sensor. This study was performed to determine its accuracy on a soft surface. Four trials, trial 1: chest compressions on the floor using an accelerometer device; trial 2: chest compressions on the floor using an IR-UWB sensor; trial 3: chest compressions on a foam mattress using an accelerometer device; trial 4: chest compressions on a foam mattress using an IR-UWB sensor, were performed in a random order. In all the trials, a cardiopulmonary resuscitation provider delivered 50 uninterrupted chest compressions to a manikin. The CCD measured by the manikin and the device were as follows: 57.42 ± 2.23 and 53.92 ± 2.92 mm, respectively in trial 1 (p < 0.001); 56.29 ± 1.96 and 54.16 ± 3.90 mm, respectively in trial 2 (p < 0.001); 55.61 ± 1.57 and 103.48 ± 10.48 mm, respectively in trial 3 (p < 0.001); 57.14 ± 3.99 and 55.51 ± 3.39 mm, respectively in trial 4 (p = 0.012). The gaps between the CCD measured by the manikin and the devices (accelerometer device vs. IR-UWB sensor) on the floor were not different (3.50 ± 2.08 mm vs. 3.15 ± 2.27 mm, respectively, p = 0.136). However, the gaps were significantly different on the foam mattress (48.53 ± 5.65 mm vs. 4.10 ± 2.47 mm, p < 0.001). The IR-UWB sensor could measure the CCD accurately both on the floor and on the foam mattress.

Development of a pneumatic tensioning device for gap measurement during total knee arthroplasty.

PubMed

Kwak, Dai-Soon; Kong, Chae-Gwan; Han, Seung-Ho; Kim, Dong-Hyun; In, Yong

2012-09-01

Despite the importance of soft tissue balancing during total knee arthroplasty (TKA), all estimating techniques are dependent on a surgeon's manual distraction force or subjective feeling based on experience. We developed a new device for dynamic gap balancing, which can offer constant load to the gap between the femur and tibia, using pneumatic pressure during range of motion. To determine the amount of distraction force for the new device, 3 experienced surgeons' manual distraction force was measured using a conventional spreader. A new device called the consistent load pneumatic tensor was developed on the basis of the biomechanical tests. Reliability testing for the new device was performed using 5 cadaveric knees by the same surgeons. Intraclass correlation coefficients (ICCs) were calculated. The distraction force applied to the new pneumatic tensioning device was determined to be 150 N. The interobserver reliability was very good for the newly tested spreader device with ICCs between 0.828 and 0.881. The new pneumatic tensioning device can enable us to properly evaluate the soft tissue balance throughout the range of motion during TKA with acceptable reproducibility.

The insertion device magnetic measurement facility: Prototype and operational procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkel, L.; Dejus, R.; Maines, J.

1993-03-01

This report is a description of the current status of the magnetic measurement facility and is a basic instructional manual for the operation of the facility and its components. Please refer to the appendices for more detailed information about specific components and procedures. The purpose of the magnetic measurement facility is to take accurate measurements of the magnetic field in the gay of the IDs in order to determine the effect of the ID on the stored particle beam and the emitted radiation. The facility will also play an important role when evaluating new ideas, novel devices, and inhouse prototypesmore » as part of the ongoing research and development program at the APS. The measurements will be performed with both moving search coils and moving Hall probes. The IDs will be evaluated by computer modeling of the emitted radiation for any given (measured) magnetic field map. The quality of the magnetic field will be described in terms of integrated multipoles for the effect on Storage Ring performance and in terms of the derived trajectories for the emitted radiation. Before being installed on the Storage Ring, every device will be measured and characterized to assure that it is compatible with Storage Ring requirements and radiation specifications. The accuracy that the APS needs to achieve for magnetic measurements will be based on these specifications.« less

Using Public Participation to Improve MELs Energy Data Collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kloss, Margarita; Cheung, Iris; Brown, Richard

Miscellaneous and electronic loads (MELs) comprise an increasing share of building energy consumption. Large-scale data collection is needed to inform meaningful energy reduction strategies because of the diversity of MELs and our lack of understanding about how people use them. Traditional methods of data collection, however, usually incur high labor and metering equipment expenses. As an alternative, this paper investigates the feasibility of crowdsourcing data collection to satisfy at least part of the data collection needs with acceptable accuracy. We assessed the reliability and accuracy of crowd-sourced data by recruiting 18 volunteers and testing our crowdsourcing protocol. The protocol askedmore » volunteers to perform measurement tasks for three MELs devices of increasing complexity 1) record power meter and MELs product characteristics, 2) identify and measure all power modes available, and 3) report the measured power. Volunteers performed reasonably well for devices with functionalities with which they were familiar, but many could not correctly identify all available power modes in complex devices. Accuracy may improve when participants measure the power used by familiar devices in their home, or by providing more specific instructions, e.g. videos. Furthermore, crowdsourcing data collection from individual homeowners has the potential to generate valuable information about MELs energy use in homes when integrated with existing programs such as Home Energy Saver and Building America.« less

Cerebral oxygenation in traumatic brain injury; Can a non-invasive frequency domain near-infrared spectroscopy device detect changes in brain tissue oxygen tension as well as the established invasive monitor?

PubMed

Davies, David James; Clancy, Michael; Dehghani, Hamid; Lucas, Samuel John Edwin; Forcione, Mario; Yakoub, Kamal Makram; Belli, Antonio

2018-06-07

The cost and highly invasive nature of brain monitoring modality in traumatic brain injury patients currently restrict its utility to specialist neurological intensive care settings. We aim to test the abilities of a frequency domain near-infrared spectroscopy (FD-NIRS) device in predicting changes in invasively measured brain tissue oxygen tension. Individuals admitted to a United Kingdom specialist major trauma centre were contemporaneously monitored with an FD-NIRS device and invasively measured brain tissue oxygen tension probe. Area under the curve receiver operating characteristic (AUROC) statistical analysis was utilised to assess the predictive power of FD-NIRS in detecting both moderate and severe hypoxia (20 and 10 mmHg, respectively), as measured invasively. 16 individuals were prospectively recruited to the investigation. Severe hypoxic episodes were detected in 9 of these individuals, with the NIRS demonstrating a broad range of predictive abilities (AUROC 0.68-0.88) from relatively poor to good. Moderate hypoxic episodes were detected in seven individuals with similar predictive performance (AUROC 0.576 - 0.905). A variable performance in the predictive powers of this FD-NIRS device to detect changes in brain tissue oxygen was demonstrated. Consequently, this enhanced NIRS technology has not demonstrated sufficient ability to replace the established invasive measurement.

Metastable defect response in CZTSSe from admittance spectroscopy

DOE PAGES

Koeper, Mark J.; Hages, Charles J.; Li, Jian V.; ...

2017-10-02

Admittance spectroscopy is a useful tool used to study defects in semiconductor materials. However, metastable defect responses in non-ideal semiconductors can greatly impact the measurement and therefore the interpretation of results. Here, admittance spectroscopy was performed on Cu2ZnSn(S,Se) 4 where metastable defect response is illustrated due to the trapping of injected carriers into a deep defect state. To investigate the metastable response, admittance measurements were performed under electrically and optically relaxed conditions in comparison to a device following a low level carrier-injection pretreatment. The relaxed measurement demonstrates a single capacitance signature while two capacitance signatures are observed for the devicemore » measured following carrier-injection. The deeper level signature, typically reported for kesterites, is activated by charge trapping following carrier injection. Both signatures are attributed to bulk level defects. The significant metastable response observed on kesterites due to charge trapping obscures accurate interpretation of defect levels from admittance spectroscopy and indicates that great care must be taken when performing and interpreting this measurement on non-ideal devices.« less

A new global and comprehensive model for ICU ventilator performances evaluation.

PubMed

Marjanovic, Nicolas S; De Simone, Agathe; Jegou, Guillaume; L'Her, Erwan

2017-12-01

This study aimed to provide a new global and comprehensive evaluation of recent ICU ventilators taking into account both technical performances and ergonomics. Six recent ICU ventilators were evaluated. Technical performances were assessed under two FIO 2 levels (100%, 50%), three respiratory mechanics combinations (Normal: compliance [C] = 70 mL cmH 2 O -1 /resistance [R] = 5 cmH 2 O L -1  s -1 ; Restrictive: C = 30/R = 10; Obstructive: C = 120/R = 20), four exponential levels of leaks (from 0 to 12.5 L min -1 ) and three levels of inspiratory effort (P0.1 = 2, 4 and 8 cmH 2 O), using an automated test lung. Ergonomics were evaluated by 20 ICU physicians using a global and comprehensive model involving physiological response to stress measurements (heart rate, respiratory rate, tidal volume variability and eye tracking), psycho-cognitive scales (SUS and NASA-TLX) and objective tasks completion. Few differences in terms of technical performance were observed between devices. Non-invasive ventilation modes had a huge influence on asynchrony occurrence. Using our global model, either objective tasks completion, psycho-cognitive scales and/or physiological measurements were able to depict significant differences in terms of devices' usability. The level of failure that was observed with some devices depicted the lack of adaptation of device's development to end users' requests. Despite similar technical performance, some ICU ventilators exhibit low ergonomics performance and a high risk of misusage.

A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

PubMed

Kim, Dohyun; Park, Sung-Ho

2016-11-01

Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A systematic approach for the accurate and rapid measurement of water vapor transmission through ultra-high barrier films

NASA Astrophysics Data System (ADS)

Kiese, Sandra; Kücükpinar, Esra; Reinelt, Matthias; Miesbauer, Oliver; Ewender, Johann; Langowski, Horst-Christian

2017-02-01

Flexible organic electronic devices are often protected from degradation by encapsulation in multilayered films with very high barrier properties against moisture and oxygen. However, metrology must be improved to detect such low quantities of permeants. We therefore developed a modified ultra-low permeation measurement device based on a constant-flow carrier-gas system to measure both the transient and stationary water vapor permeation through high-performance barrier films. The accumulation of permeated water vapor before its transport to the detector allows the measurement of very low water vapor transmission rates (WVTRs) down to 2 × 10-5 g m-2 d-1. The measurement cells are stored in a temperature-controlled chamber, allowing WVTR measurements within the temperature range 23-80 °C. Differences in relative humidity can be controlled within the range 15%-90%. The WVTR values determined using the novel measurement device agree with those measured using a commercially available carrier-gas device from MOCON®. Depending on the structure and quality of the barrier film, it may take a long time for the WVTR to reach a steady-state value. However, by using a combination of the time-dependent measurement and the finite element method, we were able to estimate the steady-state WVTR accurately with significantly shorter measurement times.

Apparatus and method for sensing motion in a microelectro-mechanical system

DOEpatents

Dickey, Fred M.; Holswade, Scott C.

1999-01-01

An apparatus and method are disclosed for optically sensing motion in a microelectromechanical system (also termed a MEMS device) formed by surface micromachining or LIGA. The apparatus operates by reflecting or scattering a light beam off a corrugated surface (e.g. gear teeth or a reference feature) of a moveable member (e.g. a gear, rack or linkage) within the MEMS device and detecting the reflected or scattered light. The apparatus can be used to characterize a MEMS device, measuring one or more performance characteristic such as spring and damping coefficients, torque and friction, or uniformity of motion of the moveable member. The apparatus can also be used to determine the direction and extent of motion of the moveable member; or to determine a particular mechanical state that a MEMS device is in. Finally, the apparatus and method can be used for providing feedback to the MEMS device to improve performance and reliability.

Comparison of intraocular lens decentration and tilt measurements using 2 Purkinje meter systems.

PubMed

Maedel, Sophie; Hirnschall, Nino; Bayer, Natascha; Markovic, Sabine; Tabernero, Juan; Artal, Pablo; Schaeffel, Frank; Findl, Oliver

2017-05-01

To evaluate the difference in intraocular lens tilt and decentration measurements with 2 Purkinje meters. Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria. Prospective evaluation of diagnostic test. This single-center study included pseudophakic patients in 2 substudies in which 3 consecutive measurements were performed with 2 Purkinje meters (Spanish and German). In substudy 1, an inexperienced examiner performed all measurements after a short learning period. In substudy 2, all measurements were taken by experienced examiners under direct supervision of the inventors of the devices. Substudy 1 included 53 pseudophakic eyes in which all 53 scans were successful with the Spanish device; however, only 35 measurements (66%) were successful with the German Purkinje meter. The mean tilt measured with the Spanish Purkinje meter was 4.35 degrees ± 2.50 (SD) and 9.20 ± 6.96 degrees with the German Purkinje meter. The mean decentration was 0.44 ± 0.19 mm and 0.74 ± 0.91 mm, (P = .44), respectively. In substudy 2 (29 pseudophakic eyes), the number of successful scans was 29 (100%) and 18 (62%) for the Spanish meter and German Purkinje meter, respectively. The mean horizontal and vertical tilt difference vector between the 2 systems was 4.89 ± 3.24 degrees and 7.57 ± 3.82 degrees, respectively. Concerning clinical feasibility, the Spanish Purkinje meter had a greater percentage of successful scans than the German device. In addition, this device measured significantly higher tilt values than the Spanish Purkinje meter. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Dichroic beamsplitter for high energy laser diagnostics

DOEpatents

LaFortune, Kai N [Livermore, CA; Hurd, Randall [Tracy, CA; Fochs, Scott N [Livermore, CA; Rotter, Mark D [San Ramon, CA; Hackel, Lloyd [Livermore, CA

2011-08-30

Wavefront control techniques are provided for the alignment and performance optimization of optical devices. A Shack-Hartmann wavefront sensor can be used to measure the wavefront distortion and a control system generates feedback error signal to optics inside the device to correct the wavefront. The system can be calibrated with a low-average-power probe laser. An optical element is provided to couple the optical device to a diagnostic/control package in a way that optimizes both the output power of the optical device and the coupling of the probe light into the diagnostics.

Conjugated polymers and their use in optoelectronic devices

DOEpatents

Marks, Tobin J.; Guo, Xugang; Zhou, Nanjia; Chang, Robert P. H.; Drees, Martin; Facchetti, Antonio

2016-10-18

The present invention relates to certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The present compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The present compounds can have good solubility in common solvents enabling device fabrication via solution processes.

Advanced patient transfer assist device with intuitive interaction control.

PubMed

Humphreys, Heather C; Choi, Young Mi; Book, Wayne J

2017-10-24

This research aims to improve patient transfers by developing a new type of advanced robotic assist device. It has multiple actuated degrees of freedom and a powered steerable base to maximize maneuverability around obstacles. An intuitive interface and control strategy allows the caregiver to simply push on the machine in the direction of desired patient motion. The control integrates measurements of both force and proximity to mitigate any potential large collision forces and provides operators information about obstacles with a form of haptic feedback. Electro-hydraulic pump controlled actuation provides high force density for the actuation. Nineteen participants performed tests to compare transfer operations (transferring a 250-lb mannequin between a wheelchair, chair, bed, and floor) and interaction control of a prototype device with a commercially available patient lift. The testing included a time study of the transfer operations and subjective rating of device performance. The results show that operators perform transfer tasks significantly faster and rate performance higher using the prototype patient transfer assist device than with a current market patient lift. With further development, features of the new patient lift can help facilitate patient transfers that are safer, easier, and more efficient for caregivers.

Polycrystalline Thin-Film Photovoltaics | Photovoltaic Research | NREL

Science.gov Websites

(CdTe) We develop processes and a range of materials for CdTe photovoltaic (PV) devices. Our work partners. Our objectives are to improve CdTe PV performance, reduce costs, and advance fundamental processes and materials related to thin-film polycrystalline PV devices, and our measurements and

40 CFR 65.158 - Performance test procedures for control devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... regulated material or as TOC (minus methane and ethane) according to the procedures specified. (1) Method 1... material or TOC, sampling sites shall be located at the inlet of the control device as specified in the... sampling sites shall ensure the measurement of total regulated material or TOC (minus methane and ethane...

Input Device Characteristics Contribute to Performance during Training to Operate a Simulated Micro-Unmanned Aerial Vehicle

DTIC Science & Technology

2010-10-01

mission, participants were given the NASA Task Load Index ( NASA TLX ) to measure subjective workload. Additional performance measures included mission...16 NASA TLX Workload Analyses...worksheet (See Appendix C), the Hidden Patterns Test (ETS, 1976), and an electronic form of the NASA Task Load Index ( TLX ; Hart & Staveland, 1988). The

Issues in Performance Measurement for Military Aviation with Applications to Air Combat Maneuvering

DTIC Science & Technology

1986-04-04

Systems Center 6c. ADDRESS (City, State, and ZIP Co*e) 7b. ADDRESS (City. State, and ZIP Code) 1040 Woodcock Road, Suite 227 Orlando, FL 32813-7100...NTSC TR-86-008 Vreuls, D., Obermayer, R. W., Goldstein, I. & Lauber, J. K. (1973). Measurement of trainee performance in a captive rotary- wing device

Enhancement of sun-tracking with optoelectronic devices

NASA Astrophysics Data System (ADS)

Wu, Jiunn-Chi

2015-09-01

Sun-tracking is one of the most challenging tasks in implementing CPV. In order to justify the additional complexity of sun-tracking, careful assessment of performance of CPV by monitoring the performance of sun-tracking is vital. Measurement of accuracy of sun-tracking is one of the important tasks in an outdoor test. This study examines techniques with three optoelectronic devices (i.e. position sensitive device (PSD), CCD and webcam). Outdoor measurements indicated that during sunny days (global horizontal insolation (GHI) > 700 W/m2), three devices recorded comparable tracking accuracy of 0.16˜0.3°. The method using a PSD has fastest sampling rate and is able to detect the sun's position without additional image processing. Yet, it cannot identify the sunlight effectively during low insolation. The techniques with a CCD and a webcam enhance the accuracy of centroid of sunlight via the optical lens and image processing. The image quality acquired using a webcam and a CCD is comparable but the webcam is more affordable than that of CCD because it can be assembled with consumer-graded products.

Performance of an extended dynamic range time delay integration charge coupled device (XDR TDI CCD) for high-intrascene dynamic range scanning

NASA Astrophysics Data System (ADS)

Levine, Peter A.; Dawson, Robin M.; Andrews, James T.; Bhaskaran, Mahalingham; Furst, David; Hsueh, Fu-Lung; Meray, Grazyna M.; Sudol, Thomas M.; Swain, Pradyumna K.; Tower, John R.

2003-05-01

Many applications, such as industrial inspection and overhead reconnaissance benefit from line scanning architectures where time delay integration (TDI) significantly improves sensitivity. CCDs are particularly well suited to the TDI architecture since charge is transferred virtually noiselessly down the column. Sarnoff's TDI CCDs have demonstrated extremely high speeds where a 7200 x 64, 8 um pixel device with 120 output ports demonstrated a vertical line transfer rate greater than 800 kHz. The most recent addition to Sarnoff's TDI technology is the implementation of extended dynamic range (XDR) in high speed, back illuminated TDI CCDs. The optical, intrascene dynamic range can be adjusted in the design of the imager with measured dynamic ranges exceeding 2,000,000:1 with no degradation in low light performance. The device provides a piecewise linear response to light where multiple slopes and break points can be set during the CCD design. A description of the device architecture and measured results from fabricated XDR TDI CCDs are presented.

Fetal heart rate monitoring device using condenser microphone sensor: Validation and comparison to standard devices.

PubMed

Ahmad, Husna Azyan Binti; El-Badawy, Ismail M; Singh, Om Prakash; Hisham, Rozana Binti; Malarvili, M B

2018-04-27

Fetal heart rate (FHR) monitoring device is highly demanded to assess the fetus health condition in home environments. Conventional standard devices such as ultrasonography and cardiotocography are expensive, bulky and uncomfortable and consequently not suitable for long-term monitoring. Herein, we report a device that can be used to measure fetal heart rate in clinical and home environments. The proposed device measures and displays the FHR on a screen liquid crystal display (LCD). The device consists of hardware that comprises condenser microphone sensor, signal conditioning, microcontroller and LCD, and software that involves the algorithm used for processing the conditioned fetal heart signal prior to FHR display. The device's performance is validated based on analysis of variance (ANOVA) test. FHR data was recorded from 22 pregnant women during the 17th to 37th week of gestation using the developed device and two standard devices; AngelSounds and Electronic Stethoscope. The results show that F-value (1.5) is less than F, (3.1) and p-value (p> 0.05). Accordingly, there is no significant difference between the mean readings of the developed and existing devices. Hence, the developed device can be used for monitoring FHR in clinical and home environments.

Comparability of anterior chamber depth measurements with partial coherence interferometry and optical low-coherence reflectometry in pseudophakic eyes.

PubMed

Luft, Nikolaus; Hirnschall, Nino; Farrokhi, Sanaz; Findl, Oliver

2015-08-01

To assess whether anterior chamber depth (ACD) measurements in pseudophakic eyes obtained with partial coherence interferometry (PCI) and optical low-coherence reflectometry (OLCR) devices can be used interchangeably. Vienna Institute for Research in Ocular Surgery, A Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria. Prospective case series. The ACD measurements in 1 eye of each pseudophakic patient were performed with the PCI-based ACMaster device and the OLCR-based Lenstar LS900 device at least 1 day postoperatively. The study comprised 65 eyes of 65 patients with a mean age of 71.7 years ± 9.0 (SD) (range 39 to 91 years). In 15 eyes, no valid ACD readings could be obtained with the OLCR device. No obvious reason for these measurement failures was identified; however, tear-film alterations shortly after surgery were suspected. No significant difference in the mean ACD in the remaining 50 eyes was found between PCI measurements (5019 ± 660 μm; range 4008 to 6181 μm) and OLCR measurements (5015 ± 663 μm; range 4017 to 6163 μm) (P = .06). Three (6%) of 50 measurements were not within the 95% limits of agreement in the Bland-Altman analysis. Pseudophakic ACD measurements with the PCI and OLCR devices can be used interchangeably. The OLCR device proved to be more user-friendly and faster; however, in a substantial number of eyes, no usable values were obtainable. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Inducer Hydrodynamic Load Measurement Devices

NASA Technical Reports Server (NTRS)

Skelley, Stephen E.; Zoladz, Thomas F.

2002-01-01

Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This "rotating balance" was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

Inducer Hydrodynamic Load Measurement Devices

NASA Technical Reports Server (NTRS)

Skelley, Stephen E.; Zoladz, Thomas F.; Turner, Jim (Technical Monitor)

2002-01-01

Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six-component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This rotating balance was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher-frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

Genetic Algorithm-Based Motion Estimation Method using Orientations and EMGs for Robot Controls

PubMed Central

Chae, Jeongsook; Jin, Yong; Sung, Yunsick

2018-01-01

Demand for interactive wearable devices is rapidly increasing with the development of smart devices. To accurately utilize wearable devices for remote robot controls, limited data should be analyzed and utilized efficiently. For example, the motions by a wearable device, called Myo device, can be estimated by measuring its orientation, and calculating a Bayesian probability based on these orientation data. Given that Myo device can measure various types of data, the accuracy of its motion estimation can be increased by utilizing these additional types of data. This paper proposes a motion estimation method based on weighted Bayesian probability and concurrently measured data, orientations and electromyograms (EMG). The most probable motion among estimated is treated as a final estimated motion. Thus, recognition accuracy can be improved when compared to the traditional methods that employ only a single type of data. In our experiments, seven subjects perform five predefined motions. When orientation is measured by the traditional methods, the sum of the motion estimation errors is 37.3%; likewise, when only EMG data are used, the error in motion estimation by the proposed method was also 37.3%. The proposed combined method has an error of 25%. Therefore, the proposed method reduces motion estimation errors by 12%. PMID:29324641

Sensor Technology Performance Characteristics- Field and Laboratory Observations

EPA Science Inventory

Observed Intangible Performance Characteristics RH and temperature impacts may be significant for some devices Internal battery lifetimes range from 4 to 24 hoursSensor packaging can interfere with accurate measurements (reactivity)Wireless communication protocols are not foolpr...

Cardiopulmonary monitoring in Thai ICUs (ICU-rESOURCE I Study).

PubMed

Chittawatanarat, Kaweesak; Wattanathum, Anan; Chaiwat, Onuma

2014-01-01

Cardiopulmonary monitoring (CPM) is rapidly progressing but data regarding CPM in Thai ICUs was unavailable. The objective of this study was to describe the situation, and gaps of CPM in Thai ICUs. Data were retrieved from the ICU-RESOURCE I study database survey CPM was divided into two aspects of device and measurement methods. These were categorized by device availability grading (AG), device availability per bed (DPB) and numeric frequency grading scale (FGS). Device availability was compared between academic and non-academic ICUs. Gap analysis of DPB and FGS was performed. Statistical significant difference was defined as p-value < 0.05. One hundred and fifty-five ICUs across Thailand participated in this study. Academic ICUs had significantly more devices available in new equipment with p < 0.05 (Vigilio, PiCCO, NICOM, esophageal pressure monitoring, transcutaneous PO2, electrical impedance tomography of lung) as well as measurement methods (stroke volume variation [SVV], pulse pressure variation [PPC], central venous oxygen saturation [ScvO2], lung mechanics). Most of new and higher technological devices had low density and few were available in all of Thai ICUs. However, in gap analysis, although these new devices and measurement techniques were available in ICUs, they were not frequently utilized. New technology devices of CPM had more availability in ACAD than in non-ACAD ICUs. Formal continuous training in new measurement methods should be established for reducing the availability and utilization gap (Thai Clinical Trial Registry: TCTR-201200005).

Finite element analysis of a percussion device for pulmonary diagnostics

NASA Astrophysics Data System (ADS)

Dhar, Aneesh

A pneumothorax is a medical condition where one or both lungs are unable to remain expanded due to air in the pleural space. Finite Element Analysis simulations were conducted on a Percussion Device, which is able to diagnose a pneumothorax using an automated percussion technique. The simulations helped determine the natural modes of vibration of the Percussion Device. These modes were then compared to the motion experimentally measured by an accelerometer on the Percussion Device. It was observed that the modes of the percussion head occurred in the range of 0 to 100 Hz, while the sensor membrane modes occurred in the range of 600 to 900 Hz. Most of these modes were found to match with peaks in the experimental spectra. The simulations performed are reliable and provide an understanding of the contribution of the normal modes to the complex signals measured using the Percussion Device.

Radiation analysis devices, radiation analysis methods, and articles of manufacture

DOEpatents

Roybal, Lyle Gene

2010-06-08

Radiation analysis devices include circuitry configured to determine respective radiation count data for a plurality of sections of an area of interest and combine the radiation count data of individual of sections to determine whether a selected radioactive material is present in the area of interest. An amount of the radiation count data for an individual section is insufficient to determine whether the selected radioactive material is present in the individual section. An article of manufacture includes media comprising programming configured to cause processing circuitry to perform processing comprising determining one or more correction factors based on a calibration of a radiation analysis device, measuring radiation received by the radiation analysis device using the one or more correction factors, and presenting information relating to an amount of radiation measured by the radiation analysis device having one of a plurality of specified radiation energy levels of a range of interest.

Fabrication and RF characterization of a single nickel silicide nanowire for an interconnect.

PubMed

Lee, Dongjin; Kang, Myunggil; Hong, Suheon; Hwang, Donghoon; Heo, Keun; Joo, Won-Jae; Kim, Sangsig; Whang, Dongmok; Hwang, Sung Woo

2013-09-01

We fabricated a nickel silicide nanowire (NiSi NW) device with a low thermal budget and characterized it by measuring the S-parameters in the radio-frequency (RF) regime. A single silicon nanowire (Si NW) was assembled on a substrate with a two-port coplanar waveguide structure using the dielectrophoresis method. Then, the Si NW on the device was perfectly transformed into a NiSi NW. The NiSi NW device was characterized by performing measurements in the DC and RF regimes. The transformation into the NiSi NW resulted in reducing about three-order more the resistance than before the transformation. Hence, the transmission of the NiSi NW device was 25 dB higher than that of the Si NW device up to gigahertz. We also discussed extracting the intrinsic properties of the NiSi NW by using de-embedding, circuit modeling, and simulation.

Above room temperature operation of InGaAs/AlGaAs/GaAs quantum cascade lasers

NASA Astrophysics Data System (ADS)

Pierścińska, D.; Gutowski, P.; Hałdaś, G.; Kolek, A.; Sankowska, I.; Grzonka, J.; Mizera, J.; Pierściński, K.; Bugajski, M.

2018-03-01

In this work we report on the performance of mid-infrared quantum cascade lasers (QCLs) based on strained InGaAs/AlGaAs grown by molecular beam epitaxy on GaAs substrate. Structures were grown with indium content from 1% to 6% in GaAs quantum wells (QW) and 45% of Al in AlGaAs barrier layers. The design results in strained heterostructure, however, no strain relaxation was observed as documented by x-ray diffraction measurements up to ∼3% of In content in QWs. The investigation of heterostructures and devices was performed, including structural measurements and electrooptical characterization of devices. Devices fabricated from epi wafers with 2.64% of In exhibited performance largely improved over GaAs/AlGaAs QCLs. Roughly two times reduction of the threshold current density was observed at lasing wavelength ∼9.45 μm. The lasers operated in pulsed mode up to T = 50 °C with characteristic temperature T 0 = 115 K. The decrease of the threshold current density has been mainly attributed to the reduction of interface roughness scattering and the increase of activation energy for the escape of carriers from the upper laser level to the 3D continuum. Further increase of In content in QWs resulted in the deterioration of device parameters.

PIN architecture for ultrasensitive organic thin film photoconductors.

PubMed

Jin, Zhiwen; Wang, Jizheng

2014-06-17

Organic thin film photoconductors (OTFPs) are expected to have wide applications in the field of optical communications, artificial vision and biomedical sensing due to their great advantages of high flexibility and low-cost large-area fabrication. However, their performances are not satisfactory at present: the value of responsivity (R), the parameter that measures the sensitivity of a photoconductor to light, is below 1 AW(-1). We believe such poor performance is resulted from an intrinsic self-limited effect of present bare blend based device structure. Here we designed a PIN architecture for OTFPs, the PIN device exhibits a significantly improved high R value of 96.5 AW(-1). The PIN architecture and the performance the PIN device shows here should represent an important step in the development of OTFPs.

PIN architecture for ultrasensitive organic thin film photoconductors

PubMed Central

Jin, Zhiwen; Wang, Jizheng

2014-01-01

Organic thin film photoconductors (OTFPs) are expected to have wide applications in the field of optical communications, artificial vision and biomedical sensing due to their great advantages of high flexibility and low-cost large-area fabrication. However, their performances are not satisfactory at present: the value of responsivity (R), the parameter that measures the sensitivity of a photoconductor to light, is below 1 AW−1. We believe such poor performance is resulted from an intrinsic self-limited effect of present bare blend based device structure. Here we designed a PIN architecture for OTFPs, the PIN device exhibits a significantly improved high R value of 96.5 AW−1. The PIN architecture and the performance the PIN device shows here should represent an important step in the development of OTFPs. PMID:24936952

Optical modeling based on mean free path calculations for quantum dot phosphors applied to optoelectronic devices.

PubMed

Shin, Min-Ho; Kim, Hyo-Jun; Kim, Young-Joo

2017-02-20

We proposed an optical simulation model for the quantum dot (QD) nanophosphor based on the mean free path concept to understand precisely the optical performance of optoelectronic devices. A measurement methodology was also developed to get the desired optical characteristics such as the mean free path and absorption spectra for QD nanophosphors which are to be incorporated into the simulation. The simulation results for QD-based white LED and OLED displays show good agreement with the experimental values from the fabricated devices in terms of spectral power distribution, chromaticity coordinate, CCT, and CRI. The proposed simulation model and measurement methodology can be applied easily to the design of lots of optoelectronics devices using QD nanophosphors to obtain high efficiency and the desired color characteristics.

Validity and reliability of simple measurement device to assess the velocity of the barbell during squats.

PubMed

Lorenzetti, Silvio; Lamparter, Thomas; Lüthy, Fabian

2017-12-06

The velocity of a barbell can provide important insights on the performance of athletes during strength training. The aim of this work was to assess the validity and reliably of four simple measurement devices that were compared to 3D motion capture measurements during squatting. Nine participants were assessed when performing 2 × 5 traditional squats with a weight of 70% of the 1 repetition maximum and ballistic squats with a weight of 25 kg. Simultaneously, data was recorded from three linear position transducers (T-FORCE, Tendo Power and GymAware), an accelerometer based system (Myotest) and a 3D motion capture system (Vicon) as the Gold Standard. Correlations between the simple measurement devices and 3D motion capture of the mean and the maximal velocity of the barbell, as well as the time to maximal velocity, were calculated. The correlations during traditional squats were significant and very high (r = 0.932, 0.990, p < 0.01) and significant and moderate to high (r = 0.552, 0.860, p < 0.01). The Myotest could only be used during the ballistic squats and was less accurate. All the linear position transducers were able to assess squat performance, particularly during traditional squats and especially in terms of mean velocity and time to maximal velocity.

Virtual Sensors for Advanced Controllers in Rehabilitation Robotics.

PubMed

Mancisidor, Aitziber; Zubizarreta, Asier; Cabanes, Itziar; Portillo, Eva; Jung, Je Hyung

2018-03-05

In order to properly control rehabilitation robotic devices, the measurement of interaction force and motion between patient and robot is an essential part. Usually, however, this is a complex task that requires the use of accurate sensors which increase the cost and the complexity of the robotic device. In this work, we address the development of virtual sensors that can be used as an alternative of actual force and motion sensors for the Universal Haptic Pantograph (UHP) rehabilitation robot for upper limbs training. These virtual sensors estimate the force and motion at the contact point where the patient interacts with the robot using the mathematical model of the robotic device and measurement through low cost position sensors. To demonstrate the performance of the proposed virtual sensors, they have been implemented in an advanced position/force controller of the UHP rehabilitation robot and experimentally evaluated. The experimental results reveal that the controller based on the virtual sensors has similar performance to the one using direct measurement (less than 0.005 m and 1.5 N difference in mean error). Hence, the developed virtual sensors to estimate interaction force and motion can be adopted to replace actual precise but normally high-priced sensors which are fundamental components for advanced control of rehabilitation robotic devices.

Design of magnetic Circuit Simulation for Curing Device of Anisotropic MRE

NASA Astrophysics Data System (ADS)

Hapipi, N.; Ubaidillah; Mazlan, S. A.; Widodo, P. J.

2018-03-01

The strength of magnetic field during fabrication of magnetorheological elastomer (MRE) plays a crucial role in order to form a pre-structured MRE. So far, gaussmeter were used to determine the magnetic intensity subjected to the MRE during curing. However, the magnetic flux reading through that measurement considered less accurate. Therefore, a simulation should be done to figure out the magnetic flux concentration around the sample. This paper investigates the simulation of magnetic field distribution in a curing device used during curing stage of anisotropic magnetorheological elastomer (MRE). The target in designing the magnetic circuit is to ensure a sufficient and uniform magnetic field to all the MRE surfaces during the curing process. The magnetic circuit design for the curing device was performed using Finite Element Method Magnetic (FEMM) to examine the magnetic flux density distribution in the device. The material selection was first done instantaneously during a magnetic simulation process. Then, the experimental validation of simulation was performed by measuring and comparing the actual flux generated within the specimen type and the one from the FEMM simulation. İt apparent that the data from FEMM simulation shows an agreement with the actual measurement. Furthermore, the FEMM results showed that the magnetic design is able to provide sufficient and uniform magnetic field all over the surfaces of the MRE.

Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

PubMed

Steenhaut, Kevin; Lapage, Koen; Bové, Thierry; De Hert, Stefan; Moerman, Annelies

2017-12-01

An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (S t O 2 ). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures S t O 2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure S t O 2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3 min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40 s, p ≤ 0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p ≤ 0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p ≤ 0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

Interinstrument comparison of remote-sensing devices and a new method for calculating on-road nitrogen oxides emissions and validation of vehicle-specific power.

PubMed

Rushton, Christopher E; Tate, James E; Shepherd, Simon P; Carslaw, David C

2018-02-01

Emissions of nitrogen oxides (NOx) by vehicles in real driving environments are only partially understood. This has been brought to the attention of the world with recent revelations of the cheating of the type of approval tests exposed in the dieselgate scandal. Remote-sensing devices offer investigators an opportunity to directly measure in situ real driving emissions of tens of thousands of vehicles. Remote-sensing NO 2 measurements are not as widely available as would be desirable. The aim of this study is to improve the ability of investigators to estimate the NO 2 emissions and to improve the confidence of the total NOx results calculated from standard remote-sensing device (RSD) measurements. The accuracy of the RSD speed and acceleration module was also validated using state-of-the-art onboard global positioning system (GPS) tracking. Two RSDs used in roadside vehicle emissions surveys were tested side by side under off-carriageway conditions away from transient pollution sources to ascertain the consistency of their measurements. The speed correlation was consistent across the range of measurements at 95% confidence and the acceleration correlation was consistent at 95% confidence intervals for all but the most extreme acceleration cases. VSP was consistent at 95% confidence across all measurements except for those at VSP ≥ 15 kW t -1 , which show a small underestimate. The controlled distribution gas nitric oxide measurements follow a normal distribution with 2σ equal to 18.9% of the mean, compared to 15% observed during factory calibration indicative of additional error introduced into the system. Systematic errors of +84 ppm were observed but within the tolerance of the control gas. Interinstrument correlation was performed, with the relationship between the FEAT and the RSD4600 being linear with a gradient of 0.93 and an R 2 of 0.85, indicating good correlation. A new method to calculate NOx emissions using fractional NO 2 combined with NO measurements made by the RSD4600 was constructed, validated, and shown to be more accurate than previous methods. Synchronized remote-sensing measurements of NO were taken using two different remote-sensing devices in an off-road study. It was found that the measurements taken by both instruments were well correlated. Fractional NO 2 measurements from a prior study, measurable on only one device, were used to create new NO x emission factors for the device that could not be measured by the second device. These estimates were validated against direct measurement of total NO x emission factors and shown to be an improvement on previous methodologies. Validation of vehicle-specific power was performed with good correlation observed.

Measurement of charge transfer potential barrier in pinned photodiode CMOS image sensors

NASA Astrophysics Data System (ADS)

Chen, Cao; Bing, Zhang; Junfeng, Wang; Longsheng, Wu

2016-05-01

The charge transfer potential barrier (CTPB) formed beneath the transfer gate causes a noticeable image lag issue in pinned photodiode (PPD) CMOS image sensors (CIS), and is difficult to measure straightforwardly since it is embedded inside the device. From an understanding of the CTPB formation mechanism, we report on an alternative method to feasibly measure the CTPB height by performing a linear extrapolation coupled with a horizontal left-shift on the sensor photoresponse curve under the steady-state illumination. The theoretical study was performed in detail on the principle of the proposed method. Application of the measurements on a prototype PPD-CIS chip with an array of 160 × 160 pixels is demonstrated. Such a method intends to shine new light on the guidance for the lag-free and high-speed sensors optimization based on PPD devices. Project supported by the National Defense Pre-Research Foundation of China (No. 51311050301095).

Accuracy of infrared thermometers in very low birth weight infants and impact on newborn behavioural states.

PubMed

Jarvis, Melanie; Guy, Katelyn J; König, Kai

2013-06-01

To study the impact on newborn behavioural states and accuracy of three infrared thermometers compared with digital axillary thermometer measurements in very low birth weight infants. Single-centre prospective observational study. Preterm infants born <1500-g birth weight were eligible. Infants were observed for pre-measurement behaviour state using a five-point neonatal behaviour observation tool. One infrared temperature was taken from each of the devices, followed by an axillary measurement. Further behaviour-state observations were recorded following infrared and axillary measurements. One hundred measurements were collected from each infrared device among a cohort of 42 very low birth weight infants. Only one infrared device showed satisfactory agreement with bias -0.071 (95% limits of agreement -0.68 to 0.54). The other two devices demonstrated poor agreement: bias -1.34; 95% limits of agreement -2.62 to -0.5 and bias -0.56; 95% limits of agreement -1.38 to 0.25. Neonatal behavioural scores showed only minimal changes when infrared measurements were performed but increased significantly following axillary measurements. The difference between the two modalities was statistically significant with a mean increase of 1.44 points following axillary measurements (95% confidence interval 1.21 to 1.67, P < 0.001). Temperature measurements taken with infrared thermometers demonstrated less disruption to preterm infants' behavioural state, however accuracy of devices varied. © 2013 The Authors. Journal of Paediatrics and Child Health © 2013 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Verification of a novel point-of-care HbA1c device in real world clinical practice by comparison to three high performance liquid chromatography instruments.

PubMed

Wang, Yufei; Peng, Wei; Tang, Junling; Dong, Lu; Gu, Chengchen; Zhang, Xin; Zhou, Jian; Jia, Weiping

2018-06-15

A real world clinical study was designed and conducted to evaluate the performance of a novel point-of-care device for determination of glycated haemoglobin A 1c (HbA 1c ), A1C EZ 2.0, in daily clinical practice. Five hundred and fourteen subjects were included in this study, and divided into three groups. HbA 1c was measured by A1C EZ 2.0 and three different high performance liquid chromatography (HPLC) devices: Bio-Rad Variant II Turbo, Tosoh HLC-723 G8 and Premier Hb9210 separately. Precision of A1C EZ 2.0 was also evaluated. Results obtained from A1C EZ 2.0 and all HPLC devices are correlated. Passing-Bablok regression analysis shows the equation of A1C EZ 2.0 results against the mean of HPLC devices with corresponding 95% confidence intervals (95% CI) for the intercept and slope is y = 0.10 (- 0.17 to 0.10) + 1.00 (1.00 to 1.04) x. Bland-Altman difference plot shows that the mean relative difference between A1C EZ 2.0 and Variant II Turbo, G8, Hb9210 and all HPLC results is 2.5%, 0.6%, 0.4% and 1.1%, respectively. In addition, 121 pairs of results determined by using both venous and capillary blood prove that the difference of two kinds of blood sample causes no notable variation when measured by A1C EZ 2.0. Precision study gives 2.3% and 1.9% of total coefficient of variation for normal and abnormal HbA 1c sample in A1C EZ 2.0. HbA 1c values measured by A1C EZ 2.0 were in good accordance with the results obtained with the reference HPLC devices.

Avalanche diodes for the generation of coherent radiation

NASA Technical Reports Server (NTRS)

Penfield, P., Jr.

1973-01-01

Solid state devices and characterization, and optimum imbedding networks for realizing best performance were investigated along with a barrier injection transit time diode. These diodes were investigated for possible application as microwave amplifiers and oscillators. Measurements were made of diode noise figures in the frequency ranges of 4 - 6 GHz. Initial results indicate that a noise figure of 6 - 8 db may be possible. Optimum device structure and fabrication techniques necessary for low noise performance were investigated. Previously published documents on electrodynamics are included.

Measurement of pattern recognition efficiency of tracks generated by ionizing radiation in a Medipix2 device

NASA Astrophysics Data System (ADS)

Bouchami, J.; Gutiérrez, A.; Holy, T.; Houdayer, A.; Jakůbek, J.; Lebel, C.; Leroy, C.; Macana, J.; Martin, J.-P.; Pospíšil, S.; Prak, S.; Sabella, P.; Teyssier, C.; CERN Medipix Collaboration

2011-05-01

Several experiments were performed to establish the Medipix2 device capabilities for track recognition and its efficiency at measuring fluxes. A Medipix2 device was exposed to 241Am, 106Ru and 137Cs radioactive sources, separately and simultaneously. It was also exposed to heavy particle beams (protons and alpha-particles), recoiled on a gold foil to reduce the incoming flux and allow the study of the detector response struck by incoming particles at different incidence angles. For three proton beams (400 keV, 4 and 10 MeV), the device was exposed to the radioactive sources on top of beam, giving a mixed radiation field. To test the reliability of track recognition with this device, the activities of the radioactive sources were extracted from the experimental data and compared to the expected activities. Rotation of the Medipix2 device allowed the test of the heavy tracks recognition at different incidence angles.

Functionalized organic semiconductor molecules to enhance charge carrier injection in electroluminescent cell

NASA Astrophysics Data System (ADS)

Yalcin, Eyyup; Kara, Duygu Akin; Karakaya, Caner; Yigit, Mesude Zeliha; Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Demic, Serafettin; Kus, Mahmut; Aboulouard, Abdelkhalk

2017-07-01

Organic semiconductor (OSC) materials as a charge carrier interface play an important role to improve the device performance of organic electroluminescent cells. In this study, 4,4″-bis(diphenyl amino)-1,1':3‧,1″-terphenyl-5'-carboxylic acid (TPA) and 4,4″-di-9H-carbazol-9-yl-1,1':3‧,1″-terphenyl-5'-carboxylic acid (CAR) has been designed and synthesized to modify indium tin oxide (ITO) layer as interface. Bare ITO and PEDOT:PSS coated on ITO was used as reference anode electrodes for comparison. Furthermore, PEDOT:PSS coated over CAR/ITO and TPA/ITO to observe stability of OSC molecules and to completely cover the ITO surface. Electrical, optical and surface characterizations were performed for each device. Almost all modified devices showed around 36% decrease at the turn on voltage with respect to bare ITO. The current density of bare ITO, ITO/CAR and ITO/TPA were measured as 288, 1525 and 1869 A/m2, respectively. By increasing current density, luminance of modified devices showed much better performance with respect to unmodified devices.

Accuracy of force and center of pressure measures of the Wii Balance Board.

PubMed

Bartlett, Harrison L; Ting, Lena H; Bingham, Jeffrey T

2014-01-01

The Nintendo Wii Balance Board (WBB) is increasingly used as an inexpensive force plate for assessment of postural control; however, no documentation of force and COP accuracy and reliability is publicly available. Therefore, we performed a standard measurement uncertainty analysis on 3 lightly and 6 heavily used WBBs to provide future users with information about the repeatability and accuracy of the WBB force and COP measurements. Across WBBs, we found the total uncertainty of force measurements to be within ± 9.1N, and of COP location within ± 4.1mm. However, repeatability of a single measurement within a board was better (4.5 N, 1.5mm), suggesting that the WBB is best used for relative measures using the same device, rather than absolute measurement across devices. Internally stored calibration values were comparable to those determined experimentally. Further, heavy wear did not significantly degrade performance. In combination with prior evaluation of WBB performance and published standards for measuring human balance, our study provides necessary information to evaluate the use of the WBB for analysis of human balance control. We suggest the WBB may be useful for low-resolution measurements, but should not be considered as a replacement for laboratory-grade force plates. Published by Elsevier B.V.

Accuracy of force and center of pressure measures of the Wii Balance Board

PubMed Central

Bartlett, Harrison L.; Ting, Lena H.; Bingham, Jeffrey T.

2013-01-01

The Nintendo Wii Balance Board (WBB) is increasingly used as an inexpensive force plate for assessment of postural control; however, no documentation of force and COP accuracy and reliability is publicly available. Therefore, we performed a standard measurement uncertainty analysis on 3 lightly and 6 heavily used WBBs to provide future users with information about the repeatability and accuracy of the WBB force and COP measurements. Across WBBs, we found the total uncertainty of force measurements to be within ±9.1 N, and of COP location within ±4.1 mm. However, repeatability of a single measurement within a board was better (4.5 N, 1.5 mm), suggesting that the WBB is best used for relative measures using the same device, rather than absolute measurement across devices. Internally stored calibration values were comparable to those determined experimentally. Further, heavy wear did not significantly degrade performance. In combination with prior evaluation of WBB performance and published standards for measuring human balance, our study provides necessary information to evaluate the use of the WBB for analysis of human balance control. We suggest the WBB may be useful for low-resolution measurements, but should not be considered as a replacement for laboratory-grade force plates. PMID:23910725

Electrical Characterization of Hughes HCMP 1853D and RCA CDP1853D N-bit, CMOS, 1-of-8 Decoder Microcircuits

NASA Technical Reports Server (NTRS)

Stokes, R. L.

1979-01-01

Electrical characterization tests were performed on two different manufactured types of integrated circuits. The devices were subjected to functional and AC and DC parametric tests at ambient temperatures of -55 C, -20 C, 25 C, 85 C, and 125 C. The data were analyzed and tabulated to show the effect of operating conditions on performance and to indicate parameter deviations among devices in each group. Accuracy was given precedence over test time efficiency where practical, and tests were designed to measure worst case performance.

Imaging of the native inversion layer in Silicon-On-Insulator wafers via Scanning Surface Photovoltage: Implications for RF device performance

NASA Astrophysics Data System (ADS)

Dahanayaka, Daminda; Wong, Andrew; Kaszuba, Philip; Moszkowicz, Leon; Slinkman, James; IBM SPV Lab Team

2014-03-01

Silicon-On-Insulator (SOI) technology has proved beneficial for RF cell phone technologies, which have equivalent performance to GaAs technologies. However, there is evident parasitic inversion layer under the Buried Oxide (BOX) at the interface with the high resistivity Si substrate. The latter is inferred from capacitance-voltage measurements on MOSCAPs. The inversion layer has adverse effects on RF device performance. We present data which, for the first time, show the extent of the inversion layer in the underlying substrate. This knowledge has driven processing techniques to suppress the inversion.

Field testing of three bedload samplers' efficiency in a gravel-bed river, Spitsbergen

NASA Astrophysics Data System (ADS)

Rachlewicz, Grzegorz; Zwoliński, Zbigniew; Kociuba, Waldemar; Stawska, Monika

2017-06-01

A comparative study of the three bedload traps was accomplished to determine the effectiveness differences between the devices. The research was carried out in two transverse sections of the proglacial, gravel-bedded Scott River (SW Svalbard) using three devices to perform direct measurements of bedload transport in the river channels. Several samplers are used for field measurements, but none of them has gained widespread acceptance as a standard so far. The paper compares transport rates collected in three bedload samplers that differ in structure and functionality: i) a portable Helley-Smith, pressure-difference bedload sampler (H-S), ii) an anchored River Bedload Trap (RBT), and iii) the portable sampler used by the Polish Hydrological Services (PIHM type C). All three samplers are constructed using the same components: a frame made of thin stainless steel sheet and a nylon bag with the same (2 mm) mesh size (except PIHM). Measurements were conducted within three consecutive days in two cross sections, in the same vertical profiles and at the same time (at intervals of 30 and 60 min). Measurements of bedload transport and water velocity were performed simultaneously. In order to determine the effectiveness and representativeness of short-term measurements using particular devices, the masses of the samples were converted into a specific rate of bedload transport and compared to the results of long-term continuous measurement (24 h measurement cycle). The results confirm that both specific transport indicators and the mass of the samples collected by the tested devices show a significant variation. Generally, the highest mass and specific transport indicators were obtained using the H-S sampler. The RBT produced moderate transport rates, while the PIHM sampler gave the lowest rates. The bedload transport rate in a profile estimated on the short-term measurements was compared to results of the continuous measurements conducted in the same cross sections. In the 7 cases we obtained underestimation (to max. 10 times) and in the next 7 cases - overestimation (to max. 114 times). Only in four cases were the results of short-term measurements similar to the continuous ones. The results obtained from the RBT sampler show the smallest variability among all tested devices.

Comparative study of the retinal nerve fibre layer thickness performed with optical coherence tomography and GDx scanning laser polarimetry in patients with primary open-angle glaucoma

PubMed Central

Wasyluk, Jaromir T.; Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona

2012-01-01

Summary Background We compared the parameters of retinal nerve fibre layer in patients with advanced glaucoma with the use of different OCT (Optical Coherence Tomograph) devices in relation to analogical measurements performed with GDx VCC (Nerve Fiber Analyzer with Variable Corneal Compensation) scanning laser polarimetry. Material/Methods Study subjects had advanced primary open-angle glaucoma, previously treated conservatively, diagnosed and confirmed by additional examinations (visual field, ophthalmoscopy of optic nerve, gonioscopy), A total of 10 patients were enrolled (9 women and 1 man), aged 18–70 years of age. Nineteen eyes with advanced glaucomatous neuropathy were examined. 1) Performing a threshold perimetry Octopus, G2 strategy and ophthalmoscopy of optic nerve to confirm the presence of advanced primary open-angle glaucoma; 2) performing a GDx VCC scanning laser polarimetry of retinal nerve fibre layer; 3) measuring the retinal nerve fibre layer thickness with 3 different optical coherence tomographs. Results The parameters of the retinal nerve fibre layer thickness are highly correlated between the GDx and OCT Stratus and 3D OCT-1000 devices in mean retinal nerve fibre layer thickness, retinal nerve fibre layer thickness in the upper sector, and correlation of NFI (GDx) with mean retinal nerve fibre layer thickness in OCT examinations. Absolute values of the retinal nerve fibre layer thickness (measured in μm) differ significantly between GDx and all OCT devices. Conclusions Examination with OCT devices is a sensitive diagnostic method of glaucoma, with good correlation with the results of GDx scanning laser polarimetry of the patients. PMID:22367131

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lombigit, L., E-mail: lojius@nm.gov.my; Rahman, Nur Aira Abd; Mohamad, Glam Hadzir Patai

A radioisotope identifier device based on large volume Co-planar grid CZT detector is current under development at Malaysian Nuclear Agency. This device is planned to be used for in-situ identification of radioisotopes based on their unique energies. This work reports on electronics testing performed on the front-end electronics (FEE) analog section comprising charge sensitive preamplifier-pulse shaping amplifier chain. This test involves measurement of charge sensitivity, pulse parameters and electronics noise. This report also present some preliminary results on the spectral measurement obtained from gamma emitting radioisotopes.

Performance of charge-injection-device infrared detector arrays at low and moderate backgrounds

NASA Technical Reports Server (NTRS)

Mckelvey, M. E.; Mccreight, C. R.; Goebel, J. H.; Reeves, A. A.

1985-01-01

Three 2 x 64 element charge injection device infrared detector arrays were tested at low and moderate background to evaluate their usefulness for space based astronomical observations. Testing was conducted both in the laboratory and in ground based telescope observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3x10 sq root of W/Hz. Array well capacity was measured to be significantly smaller than predicted. The measured sensitivity, which compares well with that of nonintegrating discrete extrinsic silicon photoconductors, shows these arrays to be useful for certain astronomical observations. However, the measured readout efficiency and frequency response represent serious limitations in low background applications.

Multi-party Measurement-Device-Independent Quantum Key Distribution Based on Cluster States

NASA Astrophysics Data System (ADS)

Liu, Chuanqi; Zhu, Changhua; Ma, Shuquan; Pei, Changxing

2018-03-01

We propose a novel multi-party measurement-device-independent quantum key distribution (MDI-QKD) protocol based on cluster states. A four-photon analyzer which can distinguish all the 16 cluster states serves as the measurement device for four-party MDI-QKD. Any two out of four participants can build secure keys after the analyzers obtains successful outputs and the two participants perform post-processing. We derive a security analysis for the protocol, and analyze the key rates under different values of polarization misalignment. The results show that four-party MDI-QKD is feasible over 280 km in the optical fiber channel when the key rate is about 10- 6 with the polarization misalignment parameter 0.015. Moreover, our work takes an important step toward a quantum communication network.

Nondestructive laboratory measurement of geotechnical and geoacoustic properties through intact core-liner

USGS Publications Warehouse

Kayen, R.E.; Edwards, B.D.; Lee, H.J.

1999-01-01

High-resolution automated measurement of the geotechnical and geoacoustic properties of soil at the U.S. Geological Survey (USGS) is performed with a state-of-the-art multi-sensor whole-core logging device. The device takes measurements, directly through intact sample-tube wall, of p-wave acoustic velocity, of soil wet bulk density, and magnetic susceptibility. This paper summarizes our methodology for determining soil-sound speed and wet-bulk density for material encased in an unsplit liner. Our methodology for nondestructive measurement allows for rapid, accurate, and high-resolution (1 cm-spaced) mapping of the mass physical properties of soil prior to sample extrusion.

A development of two-dimensional birefringence distribution measurement system with a sampling rate of 1.3 MHz

NASA Astrophysics Data System (ADS)

Onuma, Takashi; Otani, Yukitoshi

2014-03-01

A two-dimensional birefringence distribution measurement system with a sampling rate of 1.3 MHz is proposed. A polarization image sensor is developed as core device of the system. It is composed of a pixelated polarizer array made from photonic crystal and a parallel read out circuit with a multi-channel analog to digital converter specialized for two-dimensional polarization detection. By applying phase shifting algorism with circularly-polarized incident light, birefringence phase difference and azimuthal angle can be measured. The performance of the system is demonstrated experimentally by measuring actual birefringence distribution and polarization device such as Babinet-Soleil compensator.

SU-F-T-567: Sensitivity and Reproducibility of the Portal Imaging Panel for Routine FFF QC and Patient Plan Dose Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willett, A; Gilmore, M; Rowbottom, C

2016-06-15

Purpose: The purpose of this work was to see if the EPID is a viable alternative to other QA devices for routine FFF QA and plan dose measurements. Methods: Sensitivity measurements were made to assess response to small changes in field size and beam steering. QA plans were created where field size was varied from baseline values (5–5.5cm, 20–20.5cm). Beam steering was adjusted by altering values in service mode (Symmetry 0–3%). Plans were measured using the Varian portal imager (aS1200 DMI panel), QA3 (Sun Nuclear), and Starcheck Maxi (PTW). FFF beam parameters as stated in Fogliata et al were calculated.more » Constancy measurements were taken using all 3 QC devices to measure a MLC defined 20×20cm field. Two clinical SABR patient plans were measured on a Varian Edge linac, using the Portal Dosimetry module in ARIA, and results compared with analysis made using Delta4 (ScandiDos). Results: The EPID and the Starcheck performed better at detecting clinically relevant changes in field size with the QA3 performing better when detecting similar changes in beam symmetry. Consistency measurements with the EPID and Starcheck were equivalent, with comparable standard deviations. Clinical plan measurements on the EPID compared well with Delta4 results at 3%/1mm. Conclusion: Our results show that for FFF QA measurements such as field size and symmetry, using the EPID is a viable alternative to other QA devices. The EPID could potentially be used for QC measurements with a focus on geometric accuracy, such as MLC positional QA, due to its high resolution compared to other QA devices (EPID 0.34mm, Starcheck 3mm, QA3 5mm). Good agreement between Delta4 and portal dosimetry also indicated the EPID may be a suitable alternative for measurement of clinical plans.« less

Bias sputtered NbN and superconducting nanowire devices

NASA Astrophysics Data System (ADS)

Dane, Andrew E.; McCaughan, Adam N.; Zhu, Di; Zhao, Qingyuan; Kim, Chung-Soo; Calandri, Niccolo; Agarwal, Akshay; Bellei, Francesco; Berggren, Karl K.

2017-09-01

Superconducting nanowire single photon detectors (SNSPDs) promise to combine near-unity quantum efficiency with >100 megacounts per second rates, picosecond timing jitter, and sensitivity ranging from x-ray to mid-infrared wavelengths. However, this promise is not yet fulfilled, as superior performance in all metrics is yet to be combined into one device. The highest single-pixel detection efficiency and the widest bias windows for saturated quantum efficiency have been achieved in SNSPDs based on amorphous materials, while the lowest timing jitter and highest counting rates were demonstrated in devices made from polycrystalline materials. Broadly speaking, the amorphous superconductors that have been used to make SNSPDs have higher resistivities and lower critical temperature (Tc) values than typical polycrystalline materials. Here, we demonstrate a method of preparing niobium nitride (NbN) that has lower-than-typical superconducting transition temperature and higher-than-typical resistivity. As we will show, NbN deposited onto unheated SiO2 has a low Tc and high resistivity but is too rough for fabricating unconstricted nanowires, and Tc is too low to yield SNSPDs that can operate well at liquid helium temperatures. By adding a 50 W RF bias to the substrate holder during sputtering, the Tc of the unheated NbN films was increased by up to 73%, and the roughness was substantially reduced. After optimizing the deposition for nitrogen flow rates, we obtained 5 nm thick NbN films with a Tc of 7.8 K and a resistivity of 253 μΩ cm. We used this bias sputtered room temperature NbN to fabricate SNSPDs. Measurements were performed at 2.5 K using 1550 nm light. Photon count rates appeared to saturate at bias currents approaching the critical current, indicating that the device's quantum efficiency was approaching unity. We measured a single-ended timing jitter of 38 ps. The optical coupling to these devices was not optimized; however, integration with front-side optical structures to improve absorption should be straightforward. This material preparation was further used to fabricate nanocryotrons and a large-area imager device, reported elsewhere. The simplicity of the preparation and promising device performance should enable future high-performance devices.

Simple Circumcision Device: Proof-of-Concept for a Single-visit, Adjustable Device to Facilitate Safe Adult Male Circumcision

PubMed Central

Hotaling, James M; Leddy, Laura S; Haider, Mahum A; Mossanen, Matthew; Bailey, Michael R; MacConaghy, Brian; Olson, Francis; Krieger, John N

2014-01-01

Objective To conduct a proof-of-concept study to determine the potential utility of a novel, adjustable single-visit, disposable device to facilitate rapid adult circumcision. Design Prospective pilot trial of a novel surgical device Setting Tertiary care Veterans Administration medical center Patients 5 adult males Interventions Circumcisions performed by junior trainees using an adjustable, single-size surgical-assist device constructed by the University of Washington Applied Physics Laboratory. Main Outcome Measure(s) The attending surgeon and trainees completed standardized forms after each procedure to assess technical problems and ease of use. Follow-up visits were scheduled to evaluate adverse events, post-operative pain, cosmetic outcomes and participant satisfaction at 3, 8, 30 and 90 days post-operatively. Results The average operative time was 16.4 minutes. All cases were performed with local anesthesia and no case required electrocautery or conversion to standard surgery. At the post-operative day 3 visit all subjects were happy with their results and would recommend the procedure to another patient. One participant had a minor wound separation noted at the 30-day visit that resolved during follow-up. There were no wound infections, hematomas or other adverse events. Conclusions This proof-of-study suggests that the Simple Circumcision Device (SCD) may facilitate delivery of safe adult male circumcision services. PMID:24613534

A prototype wireless inertial-sensing device for measuring toe clearance.

PubMed

Lai, Daniel T H; Charry, E; Begg, R; Palaniswami, M

2008-01-01

Tripping and slipping are serious health concerns for the elderly because they result in life threatening injuries i.e., fractures and high medical costs. Our recent work in detection of tripping gait patterns has demonstrated that minimum toe clearance (MTC) is a sensitive falls risk predictor. MTC measurement has previously been done in gait laboratories and on treadmills which potentially imposes controlled walking conditions. In this paper, we describe a prototype design of a wireless device for monitoring vertical toe clearance. The sensors consists of a tri-axis accelerometer and dual-axis gyroscope connected to Crossbow sensor motes for wireless data transmission. Sensor data are transmitted to a laptop and displayed on a Matlab graphic user interface (GUI). We have performed zero base and treadmill experiments to investigate sensor performance to environmental variations and compared the calculated toe clearance against measurements made by an Optotrak motion system. It was found that device outputs were approximately independent of small ambient temperature variations, had a reliable range of 20m indoors and 50m outdoors and a maximum transmission rate of 20 packets/s. Toe clearance measurements were found to follow the Optotrak measurement trend but could be improved further by dealing with double integration errors and improving data transmission rates.

An electrochemical sensor device for measuring blood ammonia at the point of care.

PubMed

Brannelly, N T; Killard, A J

2017-05-15

The level of ammonia in blood is relevant in a number of medical conditions. While ammonia is a marker of dysfunction, elevated ammonia is itself a serious medical emergency and can lead to significant and permanent neurological impairment if not addressed quickly. Blood ammonia testing is typically performed in the central laboratory. While a number of point of care devices have been developed, these are based on classical enzymatic or colorimetric principles and have not been widely adopted. In this work, an electrochemical sensor device was developed for measuring blood ammonia. The device was based on the deposition of polyaniline nanoparticle films onto screen printed interdigitated electrodes using inkjet printing and their integration into a polymer microfabricated device with a polytetrafluoroethylene membrane. The device required a 52µL serum sample and measured the change in impedance of the sensor with respect to air at 1kHz, 5mV rms. The device was capable of the measurement of ammonia in serum across the physiologically relevant range of 25-200µM (r 2 =0.9984) and had a limit of detection of 12µM (n =3). The device showed no significant issues with common electrochemical interferences in blood. The device was also validated against a commercial spectrophotometric assay which resulted in excellent correlation (r =0.9699, p<0.0001) between both methods (n =3). When stored under desiccation, devices displayed minimal variation over time (0.64%) with respect to their impedance in air (n =12) and could be stored in desiccant for at least five months. Copyright © 2017 Elsevier B.V. All rights reserved.

The Roles and Developments needed for Diagnostics in the ITER Fusion Device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, Michael

2015-07-01

Harnessing the power from Fusion on earth is an important and challenging task. Excellent work has been carried out in this area over the years with several demonstrations of the ability to produce power. Now, a new large device is being constructed in the south of France. This is called ITER. ITER is a large-scale scientific experiment that aims to demonstrate a possibility to produce commercial energy from fusion. This project is now well underway with the many teams working on the construction and completing various aspects of the design. This device will carry up to 15 MA of plasmamore » current and produce about 500 MW of power, 400 MW approximately in high energy neutrons. The typical temperatures of the electrons inside this device are in the region of a few hundred million Kelvin. It is maintained using a magnetic field. This device is pushing several boundaries from those currently existing. As a result of this, several technologies need to be developed or extended. This is especially true for the systems or diagnostics that measure the performance and provide the control signals for this device. A diagnostic set will be installed on the ITER machine to provide the measurements necessary to control, evaluate and optimize plasma performance in ITER and to further the understanding of plasma physics. These include amongst others, measurements of the plasma shape, temperature, density, impurity concentration, and particle and energy confinement times. The system will comprise about 45 individual measuring systems drawn from the full range of modern plasma diagnostic techniques, including magnetics, lasers, X-rays, neutron cameras, impurity monitors, particle spectrometers, radiation bolometers, pressure and gas analysis, and optical fibres. These devices will have to be made to work in the new and challenging environment inside the vacuum vessel. These systems will have to cope with a range of phenomena that extend the current knowledge in the Fusion field. One amongst them is the parasitic effect of the neutrons on the while all the performing with great accuracy and precision. The levels of neutral particle flux, neutron flux and neutron fluence will be respectively about 5, 10 and 10,000 times higher than the harshest experienced in today's machines. The pulse length of the fusion reaction-or the amount of time the reaction is sustained-will be about 100 times longer. (authors)« less

Left Atrial Pressure Monitoring With an Implantable Wireless Pressure Sensor After Implantation of a Left Ventricular Assist Device

PubMed Central

Baranowski, Jacek; Delshad, Baz; Ahn, Henrik

2017-01-01

After implantation of a continuous-flow left ventricular assist device (LVAD), left atrial pressure (LAP) monitoring allows for the precise management of intravascular volume, inotropic therapy, and pump speed. In this case series of 4 LVAD recipients, we report the first clinical use of this wireless pressure sensor for the long-term monitoring of LAP during LVAD support. A wireless microelectromechanical system pressure sensor (Titan, ISS Inc., Ypsilanti, MI) was placed in the left atrium in four patients at the time of LVAD implantation. Titan sensor LAP was measured in all four patients on the intensive care unit and in three patients at home. Ramped speed tests were performed using LAP and echocardiography in three patients. The left ventricular end-diastolic diameter (cm), flow (L/min), power consumption (W), and blood pressure (mm Hg) were measured at each step. Measurements were performed over 36, 84, 137, and 180 days, respectively. The three discharged patients had equipment at home and were able to perform daily recordings. There were significant correlations between sensor pressure and pump speed, LV and LA size and pulmonary capillary wedge pressure, respectively (r = 0.92–0.99, p < 0.05). There was no device failure, and there were no adverse consequences of its use. PMID:27676410

The accuracy and promise of personal breathalysers for research: Steps toward a cost-effective reliable measure of alcohol intoxication?

PubMed

Riordan, Benjamin C; Scarf, Damian; Moradi, Saleh; Flett, Jayde A M; Carey, Kate B; Conner, Tamlin S

2017-01-01

Technology is continuing to shape the way we collect health data, including data on alcohol use. A number of technologies are being developed to objectively measure intoxication 'in the wild' without relying on self-report; the most immediate solution may be the use of personal breathalysers. In this study, we aimed to determine whether a cost-effective personal breathalyser would perform in a similar manner to a device used for roadside breath testing. We intercepted young adults ( n  = 337; 45% men) outside three concerts, administered 5-min interviews, and asked for breath samples on two devices (a personal breathalyser and a police-grade breathalyser). Participants reported having consumed an average of 7.3 standard drinks before the interview and had a mean Blood Alcohol Content of 0.077 g/dl on the police-grade device and 0.085 g/dl on the personal device. Difference scores suggested the personal breathalyser was more likely to over report Blood Alcohol Content (bias = 0.008 g/dl). Although the personal device was more likely to over report Blood Alcohol Content compared with the police-grade device, the results suggest that personal devices could be used as a measure of Blood Alcohol Content when collecting data outside of the lab.

Design and Implementation of an Underwater Sound Recording Device

PubMed Central

Martinez, Jayson J.; Myers, Josh R.; Carlson, Thomas J.; Deng, Z. Daniel; Rohrer, John S.; Caviggia, Kurt A.; Woodley, Christa M.; Weiland, Mark A.

2011-01-01

To monitor the underwater sound and pressure waves generated by anthropogenic activities such as underwater blasting and pile driving, an autonomous system was designed to record underwater acoustic signals. The underwater sound recording device (USR) allows for connections of two hydrophones or other dynamic pressure sensors, filters high frequency noise out of the collected signals, has a gain that can be independently set for each sensor, and allows for 2 h of data collection. Two versions of the USR were created: a submersible model deployable to a maximum depth of 300 m, and a watertight but not fully submersible model. Tests were performed on the USR in the laboratory using a data acquisition system to send single-frequency sinusoidal voltages directly to each component. These tests verified that the device operates as designed and performs as well as larger commercially available data acquisition systems, which are not suited for field use. On average, the designed gain values differed from the actual measured gain values by about 0.35 dB. A prototype of the device was used in a case study to measure blast pressures while investigating the effect of underwater rock blasting on juvenile Chinook salmon and rainbow trout. In the case study, maximum positive pressure from the blast was found to be significantly correlated with frequency of injury for individual fish. The case study also demonstrated that the device withstood operation in harsh environments, making it a valuable tool for collecting field measurements. PMID:22164089

Comparing the performance plateau in adult cochlear implant patients using HINT and AzBio.

PubMed

Massa, Sean T; Ruckenstein, Michael J

2014-04-01

This study aims to characterize the performance plateau in adult cochlear implant recipients after the initial postimplantation increase by using word recognition testing and an explicit definition of performance plateau. Retrospective review. Urban, tertiary referral center. One hundred twenty-five patients with 138 devices tested with AzBio were matched to 130 patients with 138 devices tested with HINT based on performed on CNC monosyllable tests. Patient's performance was measured overtime using AzBio and HINT tests to determine when and at what score their performance reached a plateau. Time from implantation to reach a performance plateau and plateau score with each test. Thirty-four devices reached a HINT plateau and 30 devices reached an AzBio plateau. Patients reached plateaus at similar times postoperatively using HINT and AzBio, 18.8 and 16.5 weeks, respectively (p = 0.476). Five patients tested with HINT plateaued at scores of 99% to 100%, whereas no patients plateaued above 92% with AzBio. Patients reached a plateau in performance at similar median times using AzBio and HINT, despite the ceiling effect of HINT in some patients. Most patients who reach a plateau did so within 4 months, but exactly when and if a patient's performance plateaus varies significantly among individuals. Further study is required to determine which test best reflects when a patient reaches his or her maximal performance in natural listening conditions.

PZEh-MO-8/Body Mass Measurement

NASA Image and Video Library

2009-06-30

ISS020-E-015853 (30 June 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 20 flight engineer, uses the IM mass measurement device to perform the PZEh-MO-8/Body Mass Measurement Russian biomedical routine assessments in the Zvezda Service Module of the International Space Station.

Validation of the Omron M6 (HEM-7001-E) upper-arm blood pressure measuring device according to the International Protocol in adults and obese adults.

PubMed

Altunkan, Sekip; Ilman, Nevzat; Kayatürk, Nur; Altunkan, Erkan

2007-08-01

Electronic blood pressure (BP) measurement devices are the preferred choice of patients owing to their user-friendly nature; however, there is a requirement to investigate the accuracy and reliability of these devices. The objective of this study is to evaluate the accuracy of the Omron M6 upper-arm BP device against the mercury sphygmomanometer in adults and obese adults according to the International Protocol criteria. One hundred and twenty-one patients, older than 30 years of age, were studied and classified on the basis of the range of the International Protocol. BP measurements at the upper arm with the Omron M6 were compared with the results obtained by two trained observers using a mercury sphygmomanometer. Nine sequential BP measurements were taken. A total of 33 participants were selected for each validation study. During the validation study, 99 measurements were performed on 33 participants for comparison. The first phase was performed on 15 participants, and if the device passed this phase, 18 more participants were selected. Having a two-fold purpose, this study was conducted on both adult and obese adult patients. Mean discrepancies and standard deviations of the monitor-mercury sphygmomanometer were 1.1+/-4.0 mmHg for systolic BP (SBP) and -0.5+/-3.5 mmHg for diastolic BP (DBP) in the adult group. The device passed phase 1 in 15 participants. In phase 2.1, out of a total of 99 comparisons, 88, 96, and 97 for SBP, and 88, 98, and 99 for DBP were <5, <10, and <15 mmHg, respectively. Mean discrepancies and standard deviations of the monitor-mercury sphygmomanometer were 1.7+/-4.8 mmHg for SBP and -0.8+/-4.3 mmHg for DBP in the obese adult group. The device passed phase 1 in 15 participants. In phase 2.1, out of a total of 99 comparisons, 82, 90, and 97 for SBP, and 80, 97, and 99 for DBP were <5, <10, and <15 mmHg, respectively. It was found that the Omron M6 automatic monitor, which measures BP at the upper arm, produced results in accordance with the criteria of phases 2.1 and 2.2 in both SBP and DBP, when applied to adults and to obese adults. It was concluded that the Omron M6 device, which measures BP at the upper arm, was deemed to be in accordance with the International Protocol criteria and can be recommended for use by adults and obese adults.

High performance low voltage organic field effect transistors on plastic substrate for amplifier circuits

NASA Astrophysics Data System (ADS)

Houin, G.; Duez, F.; Garcia, L.; Cantatore, E.; Torricelli, F.; Hirsch, L.; Belot, D.; Pellet, C.; Abbas, M.

2016-09-01

The high performance air stable organic semiconductor small molecule dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) was chosen as active layer for field effect transistors built to realize flexible amplifier circuits. Initial device on rigid Si/SiO2 substrate showed appreciable performance with hysteresis-free characteristics. A number of approaches were applied to simplify the process, improve device performance and decrease the operating voltage: they include an oxide interfacial layer to decrease contact resistance; a polymer passivation layer to optimize semiconductor/dielectric interface and an anodized high-k oxide as dielectric layer for low voltage operation. The devices fabricated on plastic substrate yielded excellent electrical characteristics, showing mobility of 1.6 cm2/Vs, lack of hysteresis, operation below 5 V and on/off current ratio above 105. An OFET model based on variable ranging hopping theory was used to extract the relevant parameters from the transfer and output characteristics, which enabled us to simulate our devices achieving reasonable agreement with the measurements

Design and testing of an innovative measurement device for tyre-road contact forces

NASA Astrophysics Data System (ADS)

Cheli, F.; Braghin, F.; Brusarosco, M.; Mancosu, F.; Sabbioni, E.

2011-08-01

The measurement of tyre-road contact forces is the first step towards the development of new control systems for improving vehicle safety and performances. Tyre-road contact forces measurement systems are very expensive and significantly modify the unsprung masses of the vehicle as well as the rotational inertia of the tyres. Thus, vehicle dynamics results are significantly affected. As a consequence, the measured contact forces do not correspond to the contact forces under real working conditions. A new low-cost tyre-road contact forces measurement system is proposed in this paper that can be applied to passenger cars. Its working principle is based on the measurement of three deformations of the wheel rim through strain gauges. The tyre-rim assembly is thus turned into a sensor for tyre-road contact forces. The influence of the strain gauges position onto the measurement results has been assessed through finite element simulations and experimental tests. It has been proven that, for a large variety of rims, the strain gauge position that leads to high signal-to-noise ratios is almost the same. A dynamic calibration procedure has been developed in order to allow the reconstruction of contact force and torque components once per wheel turn. The capability of the developed device to correctly estimate tyre-road contact forces has been assessed, in a first stage, through indoor laboratory experimental test on an MTS Flat-Trac ® testing machine. Results show that the implemented measuring system allows to reconstruct contact forces once per wheel turn with a precision that is comparable to that of existing high-cost measurement systems. Subsequently, outdoor tests with a vehicle having all four wheels equipped with the developed measuring device have also been performed. Reliability of the measurements provided by the developed sensor has been assessed by comparing the global measured longitudinal/lateral forces and the product of the measured longitudinal/lateral accelerations times the vehicle mass. A good agreement has been found during all the performed manoeuvres.

SU-E-J-53: A Phantom Design to Assist Patient Position Verification System in Daily Image-Guided RT and Comprehensive QA Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syh, J; Wu, H

2015-06-15

Purpose This study is to implement a homemade novel device with surface locking couch index to check daily radiograph (DR) function of adaPTInsight™, stereoscopic image guided system (SIGS), for proton therapy. The comprehensive daily QA checks of proton pencil beam output, field size, flatness and symmetry of spots and energy layers will be followed by using MatriXX dosimetry device. Methods The iBa MatriXX device was used to perform daily dosimetry which is also used to perform SIGS checks. A set of markers were attached to surface of MatriXX device in alignment of DRR of reconstructed CT images and daily DR.more » The novel device allows MatriXX to be fit into the cradle which was locked by couch index bars on couch surface. This will keep the MatriXX at same XY plane daily with exact coordinates. Couch height Z will be adjusted according to imaging to check isocenter-laser coincidence accuracy. Results adaPTInsight™ provides robotic couch to move in 6-degree coordinate system to align the dosimetry device to be within 1.0 mm / 1.0°. The daily constancy was tightened to be ± 0.5 mm / 0.3° compared to 1.0 mm / 1.0° before. For gantry at 0° and couch all 0° angles (@ Rt ARM 0 setting), offsets measured of the couch systems were ≤ 0.5° in roll, yaw and pitch dimensions. Conclusion Simplicity of novel device made daily image guided QA consistent with accuracy. The offset of the MatriXX isocenter-laser coincident was reproducible. Such easy task not only speeds up the setup, but it increases confidence level in detailed daily comprehensive measurements. The total SIGS alignment time has been shortened with less setup error. This device will enhance our experiences for the future QA when cone beam CT imaging modality becomes available at proton therapy center.« less

Effects on external quantum efficiency of electrochemically constructed n-ZnO/p-Cu2O photovoltaic device by annealing

NASA Astrophysics Data System (ADS)

Khoo, Pei Loon; Kikkawa, Yuuki; Shinagawa, Tsutomu; Izaki, Masanobu

2017-07-01

Cuprous oxide (Cu2O), a terrestrial abundant, low cost, nontoxic, intrinsically p-type oxide semiconductor with bandgap energy of about 2eV, has recently received increasing attention as a light absorbing layer in solar cells. However, the performances of electrochemically constructed Cu2O solar devices are poor compared to the theoretical power conversion efficiency. This research was conducted focusing on the EQE performance, which is closely related to the short circuit current of a solar device. ZnO/Cu2O-PV-devices were constructed electrochemically with 3-electrode cell on Ga:ZnO/SLG substrates; ZnO layers were deposited from an aqueous solution of 8 mmolL-1 zinc nitrate hexahydrate at 63°C, 0.01 Coulomb cm-2, and -0.8V, while Cu2O layers were deposited from aqueous solution containing 0.4 molL-1 copper (II) acetate monohydrate (pH12.5), at 40°C, 1.5 Coulomb cm-2, and -0.4V. Devices were then annealed under different temperatures of 150°C, 200°C, 250°C, and 300°C for 60 minutes with a Rapid Thermal Anneal furnace (RTA). The EQE of the devices were measured with a spectral sensitivity device and compared to the non-annealed device. Further studies were made such as morphology observation of the films by FE-SEM and measurements of X-ray diffraction patterns. Annealed samples showed improved maximum EQE at 150-200°C of annealing, indicating that EQE above 90% can be achieved, proving the validity of EQE improvement via low temperature annealing method for thin film Cu2O photovoltaic devices.

The Social Life of Learning Analytics: Cluster Analysis and the 'Performance' of Algorithmic Education

ERIC Educational Resources Information Center

Perrotta, Carlo; Williamson, Ben

2018-01-01

This paper argues that methods used for the classification and measurement of online education are not neutral and objective, but involved in the creation of the educational realities they claim to measure. In particular, the paper draws on material semiotics to examine cluster analysis as a 'performative device' that, to a significant extent,…

Continuous-variable measurement-device-independent quantum key distribution with virtual photon subtraction

NASA Astrophysics Data System (ADS)

Zhao, Yijia; Zhang, Yichen; Xu, Bingjie; Yu, Song; Guo, Hong

2018-04-01

The method of improving the performance of continuous-variable quantum key distribution protocols by postselection has been recently proposed and verified. In continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocols, the measurement results are obtained from untrusted third party Charlie. There is still not an effective method of improving CV-MDI QKD by the postselection with untrusted measurement. We propose a method to improve the performance of coherent-state CV-MDI QKD protocol by virtual photon subtraction via non-Gaussian postselection. The non-Gaussian postselection of transmitted data is equivalent to an ideal photon subtraction on the two-mode squeezed vacuum state, which is favorable to enhance the performance of CV-MDI QKD. In CV-MDI QKD protocol with non-Gaussian postselection, two users select their own data independently. We demonstrate that the optimal performance of the renovated CV-MDI QKD protocol is obtained with the transmitted data only selected by Alice. By setting appropriate parameters of the virtual photon subtraction, the secret key rate and tolerable excess noise are both improved at long transmission distance. The method provides an effective optimization scheme for the application of CV-MDI QKD protocols.

Noise performance of 0.35-(mu)m SOI CMOS devices and micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation

NASA Technical Reports Server (NTRS)

Binkley, D. M.; Hopper, C. E.; Cressler, J. D.; Mojarradi, M. M.; Blalock, B. J.

2004-01-01

This paper presents measured noise for 0.35(mu)m, silicon-on-insulator devices and a micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation. Flicker noise voltage, important for gyros having low frequency output, increases less than 32% after irradiation.

Development of a wearable plantar force measurement device for gait analysis in remote conditions.

PubMed

Hamid, Rawnak; Wijesundara, Suharshani; McMillan, Lachlan; Scott, David; Redoute, Jean-Michel; Ebeling, Peter R; Yuce, Mehmet Rasit

2017-07-01

The pressure field that exists between the foot and the supporting surface is identified as the foot plantar pressure. The information obtained from foot plantar pressure measurements has useful applications that include diagnosis of gait disturbances, optimization of footwear design, sport biomechanics and prevention of injury. Using wearable technology to measure foot plantar pressure continuously allows the collection of comprehensive real-life data sets while interfering minimally with the subject's daily activities. This paper presents the design of a wearable device to measure foot plantar pressure. Mechanical and electrical design considerations as well as data analysis are discussed. A pilot study involving 20 physically fit volunteers (15 males and 5 females, ageing from 20 - 45) performing a variety of physical activities (such as standing, walking, jumping and climbing up and down stairs) illustrate the potential of the device in terms of its wearability, and suitability for unobtrusive long-term monitoring.

Analysis of detection performance of multi band laser beam analyzer

NASA Astrophysics Data System (ADS)

Du, Baolin; Chen, Xiaomei; Hu, Leili

2017-10-01

Compared with microwave radar, Laser radar has high resolution, strong anti-interference ability and good hiding ability, so it becomes the focus of laser technology engineering application. A large scale Laser radar cross section (LRCS) measurement system is designed and experimentally tested. First, the boundary conditions are measured and the long range laser echo power is estimated according to the actual requirements. The estimation results show that the echo power is greater than the detector's response power. Secondly, a large scale LRCS measurement system is designed according to the demonstration and estimation. The system mainly consists of laser shaping, beam emitting device, laser echo receiving device and integrated control device. Finally, according to the designed lidar cross section measurement system, the scattering cross section of target is simulated and tested. The simulation results are basically the same as the test results, and the correctness of the system is proved.

Proposal of an innovative benchmark for comparison of the performance of contactless digitizers

NASA Astrophysics Data System (ADS)

Iuliano, Luca; Minetola, Paolo; Salmi, Alessandro

2010-10-01

Thanks to the improving performances of 3D optical scanners, in terms of accuracy and repeatability, reverse engineering applications have extended from CAD model design or reconstruction to quality control. Today, contactless digitizing devices constitute a good alternative to coordinate measuring machines (CMMs) for the inspection of certain parts. The German guideline VDI/VDE 2634 is the only reference to evaluate whether 3D optical measuring systems comply with the declared or required performance specifications. Nevertheless it is difficult to compare the performance of different scanners referring to such a guideline. An adequate novel benchmark is proposed in this paper: focusing on the inspection of production tools (moulds), the innovative test piece was designed using common geometries and free-form surfaces. The reference part is intended to be employed for the evaluation of the performance of several contactless digitizing devices in computer-aided inspection, considering dimensional and geometrical tolerances as well as other quantitative and qualitative criteria.

Study the performance of star sensor influenced by space radiation damage of image sensor

NASA Astrophysics Data System (ADS)

Feng, Jie; Li, Yudong; Wen, Lin; Guo, Qi; Zhang, Xingyao

2018-03-01

Star sensor is an essential component of spacecraft attitude control system. Spatial radiation can cause star sensor performance degradation, abnormal work, attitude measurement accuracy and reliability reduction. Many studies have already been dedicated to the radiation effect on Charge-Coupled Device(CCD) image sensor, but fewer studies focus on the radiation effect of star sensor. The innovation of this paper is to study the radiation effects from the device level to the system level. The influence of the degradation of CCD image sensor radiation sensitive parameters on the performance parameters of star sensor is studied in this paper. The correlation among the radiation effect of proton, the non-uniformity noise of CCD image sensor and the performance parameter of star sensor is analyzed. This paper establishes a foundation for the study of error prediction and correction technology of star sensor on-orbit attitude measurement, and provides some theoretical basis for the design of high performance star sensor.

Water Uptake Performance of Hygroscopic Heat and Moisture Exchangers after 24-Hour Tracheostoma Application.

PubMed

van den Boer, Cindy; Vas Nunes, Jonathan H; Muller, Sara H; van der Noort, Vincent; van den Brekel, Michiel W M; Hilgers, Frans J M

2014-06-01

After total laryngectomy, patients suffer from pulmonary complaints due to the shortcut of the upper airways that results in decreased warming and humidification of inspired air. Laryngectomized patients are advised to use a heat and moisture exchanger (HME) to optimize the inspired air. According to manufacturers' guidelines, these medical devices should be replaced every 24 hours. The aim of this study is to determine whether HMEs still function after 24-hour tracheostoma application. Assessment of residual water uptake capacity of used HMEs by measuring the difference between wet and dry core weight. Tertiary comprehensive cancer center. Three hygroscopic HME types were tested after use by laryngectomized patients in long-term follow-up. Water uptake of 41 used devices (including 10 prematurely replaced devices) was compared with that of control (unused) devices of the same type and with a control device with a relatively low performance. After 24 hours, the mean water uptake of the 3 device types had decreased compared with that of the control devices. For only one type was this difference significant. None of the used HMEs had a water uptake lower than that of the low-performing control device. The water uptake capacity of hygroscopic HEMs is clinically acceptable although no longer optimal after 24-hour tracheostoma application. From a functional point of view, the guideline for daily device replacement is therefore justified. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Acoustic performance of dual-electrode electrostatic sound generators based on CVD graphene on polyimide film.

PubMed

Lee, Kyoung-Ryul; Jang, Sung Hwan; Jung, Inhwa

2018-08-10

We investigated the acoustic performance of electrostatic sound-generating devices consisting of bi-layer graphene on polyimide film. The total sound pressure level (SPL) of the sound generated from the devices was measured as a function of source frequency by sweeping, and frequency spectra were measured at 1/3 octave band frequencies. The relationship between various operation conditions and total SPL was determined. In addition, the effects of changing voltage level, adding a DC offset, and using two pairs of electrodes were evaluated. It should be noted that two pairs of electrode operations improved sound generation by about 10 dB over all frequency ranges compared with conventional operation. As for the sound-generating capability, total SPL was 70 dBA at 4 kHz when an AC voltage of 100 V pp was applied with a DC offset of 100 V. Acoustic characteristics differed from other types of graphene-based sound generators, such as graphene thermoacoustic devices and graphene polyvinylidene fluoride devices. The effects of diameter and distance between electrodes were also studied, and we found that diameter greatly influenced the frequency response. We anticipate that the design information provided in this paper, in addition to describing key parameters of electrostatic sound-generating devices, will facilitate the commercial development of electrostatic sound-generating systems.

Intra- and Inter-observer Variability of Measurements of the Laxity Index on Stress Radiographs Performed with the Vezzoni-Modified Badertscher Hip Distension Device.

PubMed

Bertal, Mileva; Vezzoni, Aldo; Houdellier, Blandine; Bogaerts, Evelien; Stock, Emmelie; Polis, Ingeborgh; Deforce, Dieter; Saunders, Jimmy H; Broeckx, Bart J G

2018-06-02

 To describe and evaluate the accuracy, intra- and inter-observer variability of the laxity index (LI), used to quantify hip laxity on stress radiographs obtained with the Vezzoni-modified Badertscher distension device (VMBDD).  Stress radiographs of 10 dogs obtained with the VMBDD were measured three times by an experienced observer. Six participants with different backgrounds (two ECVDI residents, two PhD students, two veterinary assistants) followed a short presentation and performed subsequently the measurements four times in two separate sessions. The effect of self-learning, feedback and specialization on the accuracy of the measurements was assessed.  While the intra- and inter-observer variability were in agreement with other studies, the results of the experienced observer indicated that the variability can be very low. Neither feedback nor self-learning improved the results. A high degree of experience in radiographic assessment was not necessary to perform the measurements correctly.  As the LI measurements were acceptable after a short presentation, they support the use of VMBDD for a complete and correct in-house evaluation of the hip joint by trained clinicians. However, we propose that, in the context of screening, measurements should be performed by a limited number of experienced examiners, to limit the impact of the inter-observer variability. Schattauer GmbH Stuttgart.

Implementing bright light treatment for MSFC payload operations shiftworkers

NASA Technical Reports Server (NTRS)

Hayes, Benita C.; Stewart, Karen T.; Eastman, Charmane I.

1994-01-01

Intense light can phase-shift circadian rhythms and improve performance, sleep, and wellbeing during shiftwork simulations, but to date there have been very few attempts to administer light treatment to real shiftworkers. We have developed procedures for implementing light treatment and have conducted controlled trials of light treatment for MSFC Payload Operations staff during the USML-1 mission. We found that treatment had beneficial effects on fatigue, alertness, self-rated job performance, sleep, mood, and work attendance. Although there are portable bright light boxes commercially available, there is no testing protocol and little performance information available. We measure the illuminance of two candidate boxes for use in this study and found that levels were consistently lower than those advertised by manufacturers. A device was developed to enhance the illuminance output of such units. This device increased the illuminance by at least 60 % and provided additional improvements in visual comfort and overall exposure. Both the design of this device and some suggested procedures for evaluating light devices are presented.

Self-Heating Effects In Polysilicon Source Gated Transistors

PubMed Central

Sporea, R. A.; Burridge, T.; Silva, S. R. P.

2015-01-01

Source-gated transistors (SGTs) are thin-film devices which rely on a potential barrier at the source to achieve high gain, tolerance to fabrication variability, and low series voltage drop, relevant to a multitude of energy-efficient, large-area, cost effective applications. The current through the reverse-biased source barrier has a potentially high positive temperature coefficient, which may lead to undesirable thermal runaway effects and even device failure through self-heating. Using numerical simulations we show that, even in highly thermally-confined scenarios and at high current levels, self-heating is insufficient to compromise device integrity. Performance is minimally affected through a modest increase in output conductance, which may limit the maximum attainable gain. Measurements on polysilicon devices confirm the simulated results, with even smaller penalties in performance, largely due to improved heat dissipation through metal contacts. We conclude that SGTs can be reliably used for high gain, power efficient analog and digital circuits without significant performance impact due to self-heating. This further demonstrates the robustness of SGTs. PMID:26351099

Characterization of ultrafast devices using novel optical techniques

NASA Astrophysics Data System (ADS)

Ali, Md Ershad

Optical techniques have been extensively used to examine the high frequency performance of a number of devices including High Electron Mobility Transistors (HEMTs), Heterojunction Bipolar Phototransistors (HPTs) and Low Temperature GaAs (LT-GaAs) Photoconductive Switches. To characterize devices, frequency and time domain techniques, namely optical heterodyning and electro-optic sampling, having measurement bandwidths in excess of 200 GHz, were employed. Optical mixing in three-terminal devices has been extended for the first time to submillimeter wave frequencies. Using a new generation of 50-nm gate pseudomorphic InP-based HEMTs, optically mixed signals were detected to 552 GHz with a signal-to-noise ratio of approximately 5 dB. To the best of our knowledge, this is the highest frequency optical mixing obtained in three- terminal devices to date. A novel harmonic three-wave detection scheme was used for the detection of the optically generated signals. The technique involved downconversion of the signal in the device by the second harmonic of a gate-injected millimeter wave local oscillator. Measurements were also conducted up to 212 GHz using direct optical mixing and up to 382 GHz using a fundamental three-wave detection scheme. New interesting features in the bias dependence of the optically mixed signals have been reported. An exciting novel development from this work is the successful integration of near-field optics with optical heterodyning. The technique, called near-field optical heterodyning (NFOH), allows for extremely localized injection of high-frequency stimulus to any arbitrary point of an ultrafast device or circuit. Scanning the point of injection across the sample provides details of the high frequency operation of the device with high spatial resolution. For the implementation of the technique, fiber-optic probes with 100 nm apertures were fabricated. A feedback controlled positioning system was built for accurate placement and scanning of the fiber probe with nanometric precision. The applicability of the NFOH technique was first confirmed by measurements on heterojunction phototransistors at 100 GHz. Later NFOH scans were performed at 63 GHz on two other important devices, HEMTs and LT-GaAs Photoconductive Switches. Spatially resolved response characteristics of these devices revealed interesting details of their operation.

Can we use portable nitric oxide analyzer in young children?

PubMed

Kalliola, Satu; Malmberg, Pekka; Rito, Tuija; Pelkonen, Anna S; Mäkelä, Mika J

2011-07-01

Management of asthma could be improved by measuring exhaled nitric oxide (FENO). Portable hand-held FENO analyzer (NIOX MINO) is practical and small and could be used also in the primary care office. It has demonstrated good repeatability and correlation with stationary device (NIOX) in adults and school aged children, but so far there have been no reports on young children. The aim of this study was to compare conventional chemiluminescence device (NIOX) with a hand-held electrochemical device (NIOX MINO) in young children. Paired measurements of FENO were performed with the stationary chemiluminescence-based analyzer (NIOX) and with portable electrochemical device (NIOX MINO) in children with asthmatic symptoms and age-matched controls. Fifty-five children with mean (range) age of 5.7 (3.9-8.5) years were evaluated with both devices. Measurements were successful with both devices in 40 out of 57 children. NIOX MINO was more difficult to use than NIOX in this age group, success rates being 73% and 93%, respectively (P = 0.004). The reproducibility was similar and there was a close correlation between FENO measured by the two devices (r = 0.97, P < 0.001). However, Bland-Altman plot demonstrated limits of agreement that were relatively wide compared to low levels of FENO in the sample. Both devices were sensitive enough to distinguish higher FENO levels in children with asthmatic symptoms, compared to healthy controls. We conclude that NIOX MINO can be used as a screening tool for the assessment of airway inflammation in children from the age of 4 years, but its applicability is limited by lower measurement success rate and relatively poor accuracy and detection limit at low levels of FENO. Copyright © 2011 Wiley-Liss, Inc.

Evaluation of a new method for the collection and measurement of 8-isoprostane in exhaled breath for future application in nanoparticle exposure biomonitoring.

PubMed

Marie-Desvergne, Caroline; Dubosson, Muriel; Mossuz, Véronique Chamel

2018-05-14

In the field of nanoparticle exposure biomonitoring, oxidative stress biomarkers measured in exhaled breath condensate appear promising to detect early respiratory effects in workers handling nanomaterials. However, condensation is known for its poor efficiency in collecting non-volatiles in exhaled breath, leading to the low sensitivity of such measurements. Moreover, to be easily used in field studies on large groups of workers, the collection device must be disposable and convenient. In this study, we have tested a totally disposable commercial device that allows for the easy dry collection of exhaled air after filtration on a patented filter. The suitability and efficiency of the SensAbues (SB) device for collecting 8-isoprostane were evaluated and compared to the RTube (RT). Seven healthy volunteers performed two 15 min collections of exhaled breath, one with the SB and one with the RT. Blank devices were used to determine the background levels induced by each device. 8-isoprostane was measured in all samples using an EIA technique. The levels of 8-isoprostane in the exhaled breath of volunteers after collection with the SB were significantly higher than those after collection with the RT. Moreover, the levels obtained in volunteers with the SB were significantly higher than background levels obtained in blank devices, which was not the case for the RT. This is the first study to report the ability of the SB device to collect and measure 8-isoprostane in exhaled breath. The proposed method offers better sensitivity than a classical collection with the RT device and should be further explored before future application in biomonitoring studies.

Using resonant x-ray scattering to determine how structure controls the charge generation process in PCPDTBT:PC70BM solar cells

NASA Astrophysics Data System (ADS)

Pope, Michael; Waldrip, Matthew; Ferron, Thomas; Collins, Brian

Increased solar power conversion efficiencies to 12% in bulk heterojunction organic photovoltaics (OPVs) continue to brighten their prospects as an economically viable source of solar energy. It is known that OPV performance can be enhanced through processing additives that change the nanostructure. We track these critical structure-property relationships in the OPV system PCPDTBT:PC70BM while varying the amount of DIO additive. Resonant Soft X-ray Scattering reveals domain purity, domain size, and molecular orientation to highlight the system's complex dependence on DIO concentration. We will show the effect the resulting structure has on charge generation and recombination via in-situ transient and steady state optoelectronic measurements. By measuring structure, excited state dynamics and device performance all on the same sample enables direct relationships to be measured. We show that the appropriate balance of crystallinity, domain size and domain purity are important for optimized excited state dynamics and device performance.

Influence of an Interfacial Effect on the Laser Performance of a Rhodamine 6G/Cellulose Acetate Waveguide on a Vinylidene Fluoride Copolymer Layer.

PubMed

Tsutsumi, Naoto; Hirano, Yoshinori; Kinashi, Kenji; Sakai, Wataru

2018-06-12

The fluorescent properties of dyes and fluorophores in condensed matter significantly affect the laser performance of organic dye lasers and fluorescent polymer lasers. Concentration quenching of fluorescence is commonly observed in condensed matter. Several approaches have been presented to suppress such quenching, such as the use of a dendrimer and the use of effective energy transfer in a guest-host system. The enhanced fluorescence of rhodamine 6G (R6G) dye on a vinylidene fluoride polymer is an alternative method for enhancing laser performance because of the roughness of the P(VDF-TrFE) surface and the interaction between polar β-crystals of P(VDF-TrFE) and R6G dye. In this paper, a significant improvement in slope efficiency (SE) is demonstrated without a significant depression in the lasing threshold for distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers fabricated using an R6G-dispersed cellulose acetate (CA) matrix spin-coated onto a copolymer of vinylidene fluoride and trifluoroethylene P(VDF-TrFE) thin film. SEs of 3.4 and 1.3% were measured for DBR and DFB laser devices with CA/R6G on a P(VDF-TrFE) thin film, respectively, whereas an SE of less than 1.0% was measured for both corresponding laser devices without a P(VDF-TrFE) thin film. From the aspect of simple fabrication procedures, repeatability in device fabrication and performance, stability of the device, time for device fabrication, the present approach is the most preferable way for industrial applications, requiring only the additional step of spin-coating of a P(VDF-TrFE) thin film.

A new device for simple and accurate urinary pH testing by the Stone-former patient.

PubMed

Grases, Felix; Rodriguez, Adrian; Berga, Francisco; Costa-Bauza, Antonia; Prieto, Rafael Maria; Burdallo, Isabel; Cadarso, Alfredo; Jimenez-Jorquera, Cecilia; Baldi, Antonio; Garganta, Rosendo

2014-01-01

Urinary pH is an important factor linked to renal stone disease and a useful marker in the treatment of urolithiasis. Although the gold standard for measuring urinary pH utilizes a glass electrode and a pH meter, at present dipstick testing is largely used to estimate urinary pH. However, the accuracy and precision of this method may be insufficient for making clinical decisions in patients with lithiasis. The aim of this study is to describe a new device for urinary pH testing. The device includes a pH sensor based on differential measurement of an ISFET-REFET pair. The drawbacks associated with this type of configuration, namely short lifetime and manual fabrication, have been overcome in the prototype. An automatic one point calibration is performed when turning on the system. Two buffer solutions were utilized to determine the intra- and inter-day precision of the device. The pH of 30 fresh human urine samples was measured using a pH-meter, a dipstick and the new electronic device. In some cases, dipstick measurements differed from those of the pH meter by more than 0.40 units, a clinically relevant discrepancy, whereas none of the measurements made with the new electronic device differed from the results of the pH-meter by more than 0.1 pH units. This new electronic device has the possibility to be used by stone-formers to control their urinary pH at home, increasing the tools available for stone prevention and prophylaxis.

Spectral performance of DEPFET and gateable DEPFET macropixel devices

NASA Astrophysics Data System (ADS)

Bähr, A.; Aschauer, S.; Bergbauer, B.; Hermenau, K.; Lauf, T.; Lechner, P.; Lutz, G.; Majewski, P.; Meidinger, N.; Miessner, D.; Porro, M.; Richter, R.; Schaller, G.; Schopper, F.; Stefanescu, A.; Strüder, L.; Treis, J.

2014-03-01

Future x-ray observatories, such as the proposed ATHENA+ mission, will investigate bright and rapidly evolving radiation sources. To reach the scientific goals, high speed, spatial resolving sensors with excellent spectroscopic performance are mandatory. Well suited for this task are matrices of Depleted P-channel Field Effect Transistors (DEPFETs). DEPFETs provide intrinsic signal amplification, 100 percent fill factor, charge storage capability and a low read noise. Previous studies of DEPFET matrices of 256 × 256 pixels demonstrated an excellent energy resolution of 126 eV FWHM at 5.9 keV (compared to the theoretical Fano limit 120 eV). Usually these matrices are read out on demand, using e.g. the ASTEROID ASIC. Because the DEPFET is always sensitive, charge collected during the readout, causes so called misfits, which increase the background. For low frame rates this can be neglected. However, for fast timings, as suggested for ATHENA+, this effect reduces the spectral performance. We will present measurements on DEPFET macropixel structures, read out using a semi-Gaussian shaper, which demonstrate the excellent spectroscopic performance of these devices. Furthermore we will investigate the effect of misfits on the spectral background of DEPFET devices read out on demand. These measurements show the necessity to suppress misfits when the devices are operated for fast timing modes. As will be shown this can be done using so called gateable DEPFETs. The general advantage of gateable DEPFETs at fast timings, in terms of peak-to-background ratio will be demonstrated.

Testing of Anesthesia Machines and Defibrillators in Healthcare Institutions.

PubMed

Gurbeta, Lejla; Dzemic, Zijad; Bego, Tamer; Sejdic, Ervin; Badnjevic, Almir

2017-09-01

To improve the quality of patient treatment by improving the functionality of medical devices in healthcare institutions. To present the results of the safety and performance inspection of patient-relevant output parameters of anesthesia machines and defibrillators defined by legal metrology. This study covered 130 anesthesia machines and 161 defibrillators used in public and private healthcare institutions, during a period of two years. Testing procedures were carried out according to international standards and legal metrology legislative procedures in Bosnia and Herzegovina. The results show that in 13.84% of tested anesthesia machine and 14.91% of defibrillators device performance is not in accordance with requirements and should either have its results be verified, or the device removed from use or scheduled for corrective maintenance. Research emphasizes importance of independent safety and performance inspections, and gives recommendations for the frequency of inspection based on measurements. Results offer implications for adequacy of preventive and corrective maintenance performed in healthcare institutions. Based on collected data, the first digital electronical database of anesthesia machines and defibrillators used in healthcare institutions in Bosnia and Herzegovina is created. This database is a useful tool for tracking each device's performance over time.

What you can't feel won't hurt you: Evaluating haptic hardware using a haptic contrast sensitivity function.

PubMed

Salisbury, C M; Gillespie, R B; Tan, H Z; Barbagli, F; Salisbury, J K

2011-01-01

In this paper, we extend the concept of the contrast sensitivity function - used to evaluate video projectors - to the evaluation of haptic devices. We propose using human observers to determine if vibrations rendered using a given haptic device are accompanied by artifacts detectable to humans. This determination produces a performance measure that carries particular relevance to applications involving texture rendering. For cases in which a device produces detectable artifacts, we have developed a protocol that localizes deficiencies in device design and/or hardware implementation. In this paper, we present results from human vibration detection experiments carried out using three commercial haptic devices and one high performance voice coil motor. We found that all three commercial devices produced perceptible artifacts when rendering vibrations near human detection thresholds. Our protocol allowed us to pinpoint the deficiencies, however, and we were able to show that minor modifications to the haptic hardware were sufficient to make these devices well suited for rendering vibrations, and by extension, the vibratory components of textures. We generalize our findings to provide quantitative design guidelines that ensure the ability of haptic devices to proficiently render the vibratory components of textures.

The Effect of a Global, Subject, and Device-Specific Model on a Noninvasive Glucose Monitoring Multisensor System.

PubMed

Caduff, Andreas; Zanon, Mattia; Mueller, Martin; Zakharov, Pavel; Feldman, Yuri; De Feo, Oscar; Donath, Marc; Stahel, Werner A; Talary, Mark S

2015-07-01

We study here the influence of different patients and the influence of different devices with the same patients on the signals and modeling of data from measurements from a noninvasive Multisensor glucose monitoring system in patients with type 1 diabetes. The Multisensor includes several sensors for biophysical monitoring of skin and underlying tissue integrated on a single substrate. Two Multisensors were worn simultaneously, 1 on the upper left and 1 on the upper right arm by 4 patients during 16 study visits. Glucose was administered orally to induce 2 consecutive hyperglycemic excursions. For the analysis, global (valid for a population of patients), personal (tailored to a specific patient), and device-specific multiple linear regression models were derived. We find that adjustments of the model to the patients improves the performance of the glucose estimation with an MARD of 17.8% for personalized model versus a MARD of 21.1% for the global model. At the same time the effect of the measurement side is negligible. The device can equally well measure on the left or right arm. We also see that devices are equal in the linear modeling. Thus hardware calibration of the sensors is seen to be sufficient to eliminate interdevice differences in the measured signals. We demonstrate that the hardware of the 2 devices worn on the left and right arms are consistent yielding similar measured signals and thus glucose estimation results with a global model. The 2 devices also return similar values of glucose errors. These errors are mainly due to nonstationarities in the measured signals that are not solved by the linear model, thus suggesting for more sophisticated modeling approaches. © 2015 Diabetes Technology Society.

PZEh-MO-8/Body Mass Measurement in Service Module

NASA Image and Video Library

2009-05-06

ISS019-E-014222 (6 May 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 19/20 flight engineer, uses the IM mass measurement device to perform the PZEh-MO-8/Body Mass Measurement Russian biomedical routine assessments in the Zvezda Service Module of the International Space Station.

PZEh-MO-8/Body Mass Measurement in Service Module

NASA Image and Video Library

2009-05-06

ISS019-E-014216 (6 May 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 19/20 flight engineer, uses the IM mass measurement device to perform the PZEh-MO-8/Body Mass Measurement Russian biomedical routine assessments in the Zvezda Service Module of the International Space Station.

40 CFR 86.1308-84 - Dynamometer and engine equipment specifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

....e., armature current, etc.) may be used for torque measurement provided that it can be shown that... a constant speed. The flywheel torque measurement device readout shall be calibrated to the master... approximately equal useful ranges of torque measurement.) The transfer calibration shall be performed in a...

40 CFR 86.1308-84 - Dynamometer and engine equipment specifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

....e., armature current, etc.) may be used for torque measurement provided that it can be shown that... a constant speed. The flywheel torque measurement device readout shall be calibrated to the master... approximately equal useful ranges of torque measurement.) The transfer calibration shall be performed in a...

Comparison of corneal power, astigmatism, and wavefront aberration measurements obtained by a point-source color light-emitting diode-based topographer, a Placido-disk topographer, and a combined Placido and dual Scheimpflug device.

PubMed

Ventura, Bruna V; Wang, Li; Ali, Shazia F; Koch, Douglas D; Weikert, Mitchell P

2015-08-01

To evaluate and compare the performance of a point-source color light-emitting diode (LED)-based topographer (color-LED) in measuring anterior corneal power and aberrations with that of a Placido-disk topographer and a combined Placido and dual Scheimpflug device. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas USA. Retrospective observational case series. Normal eyes and post-refractive-surgery eyes were consecutively measured using color-LED, Placido, and dual-Scheimpflug devices. The main outcome measures were anterior corneal power, astigmatism, and higher-order aberrations (HOAs) (6.0 mm pupil), which were compared using the t test. There were no statistically significant differences in corneal power measurements in normal and post-refractive surgery eyes and in astigmatism magnitude in post-refractive surgery eyes between the color-LED device and Placido or dual Scheimpflug devices (all P > .05). In normal eyes, there were no statistically significant differences in 3rd-order coma and 4th-order spherical aberration between the color-LED and Placido devices and in HOA root mean square, 3rd-order coma, 3rd-order trefoil, 4th-order spherical aberration, and 4th-order secondary astigmatism between the color-LED and dual Scheimpflug devices (all P > .05). In post-refractive surgery eyes, the color-LED device agreed with the Placido and dual-Scheimpflug devices regarding 3rd-order coma and 4th-order spherical aberration (all P > .05). In normal and post-refractive surgery eyes, all 3 devices were comparable with respect to corneal power. The agreement in corneal aberrations varied. Drs. Wang, Koch, and Weikert are consultants to Ziemer Ophthalmic Systems AG. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics Corp. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Hybrid motion sensing and experimental modal analysis using collocated smartphone camera and accelerometers

NASA Astrophysics Data System (ADS)

Ozer, Ekin; Feng, Dongming; Feng, Maria Q.

2017-10-01

State-of-the-art multisensory technologies and heterogeneous sensor networks propose a wide range of response measurement opportunities for structural health monitoring (SHM). Measuring and fusing different physical quantities in terms of structural vibrations can provide alternative acquisition methods and improve the quality of the modal testing results. In this study, a recently introduced SHM concept, SHM with smartphones, is focused to utilize multisensory smartphone features for a hybridized structural vibration response measurement framework. Based on vibration testing of a small-scale multistory laboratory model, displacement and acceleration responses are monitored using two different smartphone sensors, an embedded camera and accelerometer, respectively. Double-integration or differentiation among different measurement types is performed to combine multisensory measurements on a comparative basis. In addition, distributed sensor signals from collocated devices are processed for modal identification, and performance of smartphone-based sensing platforms are tested under different configuration scenarios and heterogeneity levels. The results of these tests show a novel and successful implementation of a hybrid motion sensing platform through multiple sensor type and device integration. Despite the heterogeneity of motion data obtained from different smartphone devices and technologies, it is shown that multisensory response measurements can be blended for experimental modal analysis. Getting benefit from the accessibility of smartphone technology, similar smartphone-based dynamic testing methodologies can provide innovative SHM solutions with mobile, programmable, and cost-free interfaces.

Intercomparison of active, passive and continuous instruments for radon and radon progeny measurements in the EML chamber and test facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarpitta, S.C.; Tu, K.W.; Fisenne, I.M.

1996-10-01

Results are presented from the Fifth Intercomparison of Active, Passive and Continuous Instruments for Radon and Radon Progeny Measurements conducted in the EML radon exposure and test facility in May 1996. In total, thirty-four government, private and academic facilities participated in the exercise with over 170 passive and electronic devices exposed in the EML test chamber. During the first week of the exercise, passive and continuous measuring devices were exposed (usually in quadruplicate) to about 1,280 Bq m{sup {minus}3} {sup 222}Rn for 1--7 days. Radon progeny measurements were made during the second week of the exercise. The results indicate thatmore » all of the tested devices that measure radon gas performed well and fulfill their intended purpose. The grand mean (GM) ratio of the participants` reported values to the EML values, for all four radon device categories, was 0.99 {plus_minus} 0.08. Eighty-five percent of all the radon measuring devices that were exposed in the EML radon test chamber were within {plus_minus}1 standard deviation (SD) of the EML reference values. For the most part, radon progeny measurements were also quite good as compared to the EML values. The GM ratio for the 10 continuous PAEC instruments was 0.90 {plus_minus} 0.12 with 75% of the devices within 1 SD of the EML reference values. Most of the continuous and integrating electronic instruments used for measuring the PAEC underestimated the EML values by about 10--15% probably because the concentration of particles onto which the radon progeny were attached was low (1,200--3,800 particles cm{sup {minus}3}). The equilibrium factor at that particle concentration level was 0.10--0.22.« less

Performance Measurement of a Multi-Level/Analog Ferroelectric Memory Device Design

NASA Technical Reports Server (NTRS)

MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

2007-01-01

Increasing the memory density and utilizing the unique characteristics of ferroelectric devices is important in making ferroelectric memory devices more desirable to the consumer. This paper describes the characterization of a design that allows multiple levels to be stored in a ferroelectric based memory cell. It can be used to store multiple bits or analog values in a high speed nonvolatile memory. The design utilizes the hysteresis characteristic of ferroelectric transistors to store an analog value in the memory cell. The design also compensates for the decay of the polarization of the ferroelectric material over time. This is done by utilizing a pair of ferroelectric transistors to store the data. One transistor is used a reference to determinethe amount of decay that has occurred since the pair was programmed. The second transistor stores the analog value as a polarization value between zero and saturated. The design allows digital data to be stored as multiple bits in each memory cell. The number of bits per cell that can be stored will vary with the decay rate of the ferroelectric transistors and the repeatability of polarization between transistors. This paper presents measurements of an actual prototype memory cell. This prototype is not a complete implementation of a device, but instead, a prototype of the storage and retrieval portion of an actual device. The performance of this prototype is presented with the projected performance of the overall device. This memory design will be useful because it allows higher memory density, compensates for the environmental and ferroelectric aging processes, allows analog values to be directly stored in memory, compensates for the thermal and radiation environments associated with space operations, and relies only on existing technologies.

Fused thiophene-based conjugated polymers and their use in optoelectronic devices

DOEpatents

Facchetti, Antonio; Marks, Tobin J; Takai, Atsuro; Seger, Mark; Chen, Zhihua

2015-11-03

The present teachings relate to certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The disclosed compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The disclosed compounds can have good solubility in common solvents enabling device fabrication via solution processes.

Sternal Skin Conductance: A reasonable surrogate for Hot Flash Measurement?

PubMed Central

Pachman, Deirdre R.; Loprinzi, Charles L.; Novotny, Paul J; Satele, Daniel V; Linquist, Breanna M.; Wolf, Sherry; Barton, Debra L.

2013-01-01

Objective The aim of this study was to examine the accuracy of a new sternal skin conductance (SSC) device for the measurement of hot flashes, and secondly, to assess the acceptability of the device by women. Methods Three small descriptive pilot studies were performed utilizing two sequential prototypes of the SSC device developed by an engineering device company in the Midwest. The devices were worn either in a monitored setting for 24 hours or in an ambulatory setting for 5 weeks. During the study period, women recorded hot flashes in a prospective hot flash diary and also answered questions about the acceptability of wearing the SSC device. Results The first prototype was not able to collect any analyzable skin conductance data due to various malfunction issues; including poor conductance and battery failure. However, 16 patients did wear the device for 5 weeks and reported that wearing the device was acceptable, although 31% stated that it did interfere with daily activities. Hot flash data from the second prototype revealed a concordance rate between patient reported and device recorded hot flashes of 24%. Conclusions Findings from these studies support the discordance between SSC recorded and patient reported hot flashes. In addition, the studies reveal further limitations of SSC monitoring, including difficulties with data collection and lack of consistency in interpretation. Based on these results and other recent trials identifying issues with SSC methodology, it is time to find a better physiologic surrogate measure for hot flashes. PMID:23571528

Simultaneous 3D-vibration measurement using a single laser beam device

NASA Astrophysics Data System (ADS)

Brecher, Christian; Guralnik, Alexander; Baümler, Stephan

2012-06-01

Today's commercial solutions for vibration measurement and modal analysis are 3D-scanning laser doppler vibrometers, mainly used for open surfaces in the automotive and aerospace industries and the classic three-axial accelerometers in civil engineering, for most industrial applications in manufacturing environments, and particularly for partially closed structures. This paper presents a novel measurement approach using a single laser beam device and optical reflectors to simultaneously perform 3D-dynamic measurement as well as geometry measurement of the investigated object. We show the application of this so called laser tracker for modal testing of structures on a mechanical manufacturing shop floor. A holistic measurement method is developed containing manual reflector placement, semi-automated geometric modeling of investigated objects and fully automated vibration measurement up to 1000 Hz and down to few microns amplitude. Additionally the fast set up dynamic measurement of moving objects using a tracking technique is presented that only uses the device's own functionalities and does neither require a predefined moving path of the target nor an electronic synchronization to the moving object.

A biomechanical and physiological study of office seat and tablet device interaction.

PubMed

Weston, Eric; Le, Peter; Marras, William S

2017-07-01

Twenty subjects performed typing tasks on a desktop computer and touch-screen tablet in two chairs for an hour each, and the effects of chair, device, and their interactions on each dependent measure were recorded. Biomechanical measures of muscle force, spinal load, and posture were examined, while discomfort was measured via heart rate variability (HRV) and subjective reports. HRV was sensitive enough to differentiate between chair and device interactions. Biomechanically, a lack of seat back mobility forced individuals to maintain an upright seating posture with increased extensor muscle forces and increased spinal compression. Effects were exacerbated by forward flexion upon interaction with a tablet device or by slouching. Office chairs should be designed with both the human and workplace task in mind and allow for reclined postures to off-load the spine. The degree of recline should be limited, however, to prevent decreased lumbar lordosis resulting from posterior hip rotation in highly reclined postures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Position calibration of a 3-DOF hand-controller with hybrid structure

NASA Astrophysics Data System (ADS)

Zhu, Chengcheng; Song, Aiguo

2017-09-01

A hand-controller is a human-robot interactive device, which measures the 3-DOF (Degree of Freedom) position of the human hand and sends it as a command to control robot movement. The device also receives 3-DOF force feedback from the robot and applies it to the human hand. Thus, the precision of 3-DOF position measurements is a key performance factor for hand-controllers. However, when using a hybrid type 3-DOF hand controller, various errors occur and are considered originating from machining and assembly variations within the device. This paper presents a calibration method to improve the position tracking accuracy of hybrid type hand-controllers by determining the actual size of the hand-controller parts. By re-measuring and re-calibrating this kind of hand-controller, the actual size of the key parts that cause errors is determined. Modifying the formula parameters with the actual sizes, which are obtained in the calibrating process, improves the end position tracking accuracy of the device.

A Multi-Technique Reconfigurable Electrochemical Biosensor: Enabling Personal Health Monitoring in Mobile Devices.

PubMed

Sun, Alexander; Venkatesh, A G; Hall, Drew A

2016-10-01

This paper describes the design and characterization of a reconfigurable, multi-technique electrochemical biosensor designed for direct integration into smartphone and wearable technologies to enable remote and accurate personal health monitoring. By repurposing components from one mode to the next, the biosensor's potentiostat is able reconfigure itself into three different measurements modes to perform amperometric, potentiometric, and impedance spectroscopic tests all with minimal redundant devices. A [Formula: see text] PCB prototype of the module was developed with discrete components and tested using Google's Project Ara modular smartphone. The amperometric mode has a ±1 nA to [Formula: see text] measurement range. When used to detect pH, the potentiometric mode achieves a resolution of < 0.08 pH units. In impedance measurement mode, the device can measure 50 Ω-10 [Formula: see text] and has been shown to have of phase error. This prototype was used to perform several point-of-care health tracking assays suitable for use with mobile devices: 1) Blood glucose tests were conducted and shown to cover the diagnostic range for Diabetic patients (  ∼  200 mg/dL). 2) Lactoferrin, a biomarker for urinary tract infections, was detected with a limit of detection of approximately 1 ng/mL. 3) pH tests of sweat were conducted to track dehydration during exercise. 4) EIS was used to determine the concentration of NeutrAvidin via a label-free assay.

Bench evaluation: three face-shield CPR barrier devices.

PubMed

Simmons, M; Deao, D; Moon, L; Peters, K; Cavanaugh, S

1995-06-01

Due to the fear of disease transmission, the practice of mouth-to-mouth (M-M) rescue breathing is rarely performed; to address this concern, many types of CPR barrier devices have been developed. These include bag-valve-mask devices, mouth-to-mask devices, and face shields (FS). The purpose of this study was to measure the volumes delivered during mouth-to-face shield (M-FS) breathing, to measure the back pressure and calculate the resistance to flow through their 1-way valves, and to test for backward leak of gas through the valves. Three FS brands were evaluated: Kiss of Life (KOL), MicroSHIELD (Micro) and Res-Cue Key (RCK). Volume delivered during M-M and M-FS breathing was evaluated by 10 rescuers who used the devices while performing rescue breathing on a CPR mannequin. Back pressure was measured and resistance calculated by directing airflow through the 1-way valves. Backward leak was evaluated by measuring the O2 concentration at the rescuer side of the valve while 100% O2 was directed toward the patient side of the valve. Differences among the brands were evaluated using analysis of variance. The mean (SD) values for volumes in L were: M-M 1.00 (0.25), Micro 0.77 (0.20), RCK 0.64 (0.10), and KOL 0.24 (0.11). Mean values for back pressure in cm H2O at 50 L/min were Micro 16.7 (1.29), KOL 7.22 (0.13), and RCK 2.15 (0.16). Significant backward leak only occurred with RCK. Not one of the FSs tested met all of the requirements suggested by the American Heart Association and by the International Standards Organization.

Process tool monitoring and matching using interferometry technique

NASA Astrophysics Data System (ADS)

Anberg, Doug; Owen, David M.; Mileham, Jeffrey; Lee, Byoung-Ho; Bouche, Eric

2016-03-01

The semiconductor industry makes dramatic device technology changes over short time periods. As the semiconductor industry advances towards to the 10 nm device node, more precise management and control of processing tools has become a significant manufacturing challenge. Some processes require multiple tool sets and some tools have multiple chambers for mass production. Tool and chamber matching has become a critical consideration for meeting today's manufacturing requirements. Additionally, process tools and chamber conditions have to be monitored to ensure uniform process performance across the tool and chamber fleet. There are many parameters for managing and monitoring tools and chambers. Particle defect monitoring is a well-known and established example where defect inspection tools can directly detect particles on the wafer surface. However, leading edge processes are driving the need to also monitor invisible defects, i.e. stress, contamination, etc., because some device failures cannot be directly correlated with traditional visualized defect maps or other known sources. Some failure maps show the same signatures as stress or contamination maps, which implies correlation to device performance or yield. In this paper we present process tool monitoring and matching using an interferometry technique. There are many types of interferometry techniques used for various process monitoring applications. We use a Coherent Gradient Sensing (CGS) interferometer which is self-referencing and enables high throughput measurements. Using this technique, we can quickly measure the topography of an entire wafer surface and obtain stress and displacement data from the topography measurement. For improved tool and chamber matching and reduced device failure, wafer stress measurements can be implemented as a regular tool or chamber monitoring test for either unpatterned or patterned wafers as a good criteria for improved process stability.

Effectiveness of a personalized device in the evaluation of mandibular second molar periodontal healing after surgical extraction of adjacent third molar.

PubMed

Pippi, Roberto

2013-01-01

The primary aim of the present study was to validate the effectiveness of a personalized device able to guide periodontal probing in evaluation of second molar periodontal healing after adjacent third molar surgical extraction. Secondarily, the study analyzed if any patient and tooth related factors affected the second molar periodontal healing as well as if they were able to affect the periodontal probing depth performed with or without the personalized device. Thirty-five lower second molars were evaluated after extraction of the adjacent third molar. Pre-operative as well as 3 and 12 month post-operative probing depths of the distal surface of the second molar were evaluated. All measurements were taken by two different methods: standard two-point and four-point probing using a personalized onlay-type guide. Periapical radiographs were also evaluated. The Pearson product moment and the general linear model with backward stepwise procedure were used for inferential statistics. The mean 12-month post-operative probing depth/mean pre-operative probing depth ratio obtained with the guided probing method showed a highly significant effect on the 12-month radiographic post-operative/pre-operative radiographic measure ratio. None of the examined patient- or tooth-related factors showed a significant effect on pre-operative/12-month post-operative radiographic measure ratio. The use of the proposed personalized device seems to provide a more reliable estimate of second molar periodontal healing after adjacent third molar surgical extraction. No patient-or tooth-related factors seem to be able to affect either second molar periodontal healing or probing depth measures obtained with or without the personalized device in individuals younger than 25 years old. It can be therefore recommended that lower third molar surgical extraction be performed in young adults.

Mechanical device for determining the stiffness and the viscous friction coefficient of shock absorber elements modelled by bond graph

NASA Astrophysics Data System (ADS)

Ibănescu, R.; Ibănescu, M.

2016-11-01

The present paper presents a mechanical device for the assessment of the fundamental parameters of a shock absorber: the spring stiffness and the viscous friction coefficient, without disassembling the absorber. The device produces an oscillatory motion of the shock absorber and can measure its amplitude and angular velocities. The dynamic model of the system, consisting of the mechanical device and the shock absorber, is performed by using the bond- graph method. Based on this model, the motion equations are obtained, which by integration lead to the motion law. The two previously mentioned parameters are determined by using this law and the measured values of two amplitudes and of their corresponding angular velocities. They result as solutions of a system of two non-linear algebraic equations.

Micromachined modulator arrays for use in free-space optical communication systems

NASA Astrophysics Data System (ADS)

Lewis, Keith L.; Ridley, Kevin D.; McNie, Mark E.; Smith, Gilbert W.; Scott, Andrew M.

2004-12-01

A summary is presented of some of the design criteria relevant to the realisation of silicon micromachined modulator arrays for use in free-space optical communication systems. Theoretical performance levels achievable are compared with values measured on experimental devices produced using a modified Multi-User MEMS Process (MUMPS). Devices capable of realising modulation rates in excess of 300 kHz are described and their optical characteristics compared with published data on devices based on multiple quantum well technology.

Data on the detail information of influence of substrate temperature on the film morphology and photovoltaic performance of non-fullerene organic solar cells.

PubMed

Zhang, Jicheng; Xie, SuFei; Lu, Zhen; Wu, Yang; Xiao, Hongmei; Zhang, Xuejuan; Li, Guangwu; Li, Cuihong; Chen, Xuebo; Ma, Wei; Bo, Zhishan

2017-10-01

This data contains additional data related to the article "Influence of Substrate Temperature on the Film Morphology and Photovoltaic Performance of Non-fullerene Organic Solar Cells" (Jicheng Zhang et al., In press) [1]. Data include measurement and characterization instruments and condition, detail condition to fabricate norfullerene solar cell devices, hole-only and electron-only devices. Detail condition about how to control the film morphology of devices via tuning the temperature of substrates was also displayed. More information and more convincing data about the change of film morphology for active layers fabricated from different temperature, which is attached to the research article of "Influence of Substrate Temperature on the Film Morphology and Photovoltaic Performance of Non-fullerene Organic Solar Cells" was given.

Collection-limited theory interprets the extraordinary response of single semiconductor organic solar cells

PubMed Central

Ray, Biswajit; Baradwaj, Aditya G.; Khan, Mohammad Ryyan; Boudouris, Bryan W.; Alam, Muhammad Ashraful

2015-01-01

The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. Here we show that the short-circuit current density from SS-OPV devices can be enhanced significantly (∼100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: (i) detailed numerical simulations, (ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and (iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. These insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials. PMID:26290582

Collection-limited theory interprets the extraordinary response of single semiconductor organic solar cells.

PubMed

Ray, Biswajit; Baradwaj, Aditya G; Khan, Mohammad Ryyan; Boudouris, Bryan W; Alam, Muhammad Ashraful

2015-09-08

The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. Here we show that the short-circuit current density from SS-OPV devices can be enhanced significantly (∼100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: (i) detailed numerical simulations, (ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and (iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. These insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials.

Pediatric Perimeter-A Novel Device to Measure Visual Fields in Infants and Patients with Special Needs.

PubMed

Satgunam, PremNandhini; Datta, Sourav; Chillakala, Koteswararao; Bobbili, Karthik R; Joshi, Dhruv

2017-07-01

There are no commercially available devices to measure visual fields in infants. We developed a device, "Pediatric Perimeter," that quantifies visual field extent (VFE) for infants. We describe the construction, validation, and use of this device. A hemispherical dome with light emitting diodes (LEDs) was constructed. The LEDs were controlled using a computer program to measure reaction time (RT) to gross visual fields (GVF) and the VFE. Participants were tested in supine position in a dark room. Eye or head movement towards the stimuli was monitored with an infrared (IR) camera. Validation was done on 10 adults (mean age: 24.4 ± 5 years) with tunnel vision simulator. Perimetry was performed on 19 infants (age: 2.3-12 months), five infants with normal milestones. GVF and VFE were estimated in 17 and 7 infants, respectively. Median RT of infants with developmental delay was 663 ms and 380 ms for healthy infants. Also, 14 children (age: 14 months-6 years) with developmental delay and five patients with cognitive impairment were tested. Visual field isopter and RT can be examined with the Pediatric Perimeter device on infants and patients with special needs. Further testing on infants will need to assess the repeatability. A large-scale study will be needed to compare typically developing infants and infants with delayed milestones with this device. Quantifiable parameters obtained with this device can be used as outcome measures in clinical examination of infants and patients with special needs. This device can be used in pediatric, neurology, and ophthalmology clinics.

Photovoltaic Performance and Reliability Workshop summary

NASA Astrophysics Data System (ADS)

Kroposki, Benjamin

1997-02-01

The objective of the Photovoltaic Performance and Reliability Workshop was to provide a forum where the entire photovoltaic (PV) community (manufacturers, researchers, system designers, and customers) could get together and discuss technical issues relating to PV. The workshop included presentations from twenty-five speakers and had more than one hundred attendees. This workshop also included several open sessions in which the audience and speakers could discuss technical subjects in depth. Several major topics were discussed including: PV characterization and measurements, service lifetimes for PV devices, degradation and failure mechanisms for PV devices, standardization of testing procedures, AC module performance and reliability testing, inverter performance and reliability testing, standardization of utility interconnect requirements, experience from field deployed systems, and system certification.

Enabling optical metrology on small 5×5μm2 in-cell targets to support flexible sampling and higher order overlay and CD control for advanced logic devices nodes

NASA Astrophysics Data System (ADS)

Salerno, Antonio; de la Fuente, Isabel; Hsu, Zack; Tai, Alan; Chang, Hammer; McNamara, Elliott; Cramer, Hugo; Li, Daoping

2018-03-01

In next generation Logic devices, overlay control requirements shrink to sub 2.5nm level on-product overlay. Historically on-product overlay has been defined by the overlay capability of after-develop in-scribe targets. However, due to design and dimension, the after development metrology targets are not completely representative for the final overlay of the device. In addition, they are confined to the scribe-lane area, which limits the sampling possibilities. To address these two issues, metrology on structures matching the device structure and which can be sampled with high density across the device is required. Conventional after-etch CDSEM techniques on logic devices present difficulties in discerning the layers of interest, potential destructive charging effects and finally, they are limited by the long measurement times[1] [2] [3] . All together, limit the sampling densities and making CDSEM less attractive for control applications. Optical metrology can overcome most of these limitations. Such measurement, however, does require repetitive structures. This requirement is not fulfilled by logic devices, as the features vary in pitch and CD over the exposure field. The solution is to use small targets, with a maximum pad size of 5x5um2 , which can easily be placed in the logic cell area. These targets share the process and architecture of the device features of interest, but with a modified design that replicates as close as possible the device layout, allowing for in-device metrology for both CD and Overlay. This solution enables measuring closer to the actual product feature location and, not being limited to scribe-lanes, it opens the possibility of higher-density sampling schemes across the field. In summary, these targets become the facilitator of in-device metrology (IDM), that is, enabling the measurements both in-device Overlay and the CD parameters of interest and can deliver accurate, high-throughput, dense and after-etch measurements for Logic. Overlay improvements derived from a high-densely sampled Overlay map measured with 5x5 um2 In Device Metrology (IDM) targets were investigated on a customer Logic application. In this work we present both the main design aspects of the 5x5 um2 IDM targets, as well as the results on the improved Overlay performance.

Advancing the Technology of Monolithic CMOS detectors for their use as X-ray Imaging Spectrometers

NASA Astrophysics Data System (ADS)

Kenter, Almus

The Smithsonian Astrophysical Observatory (SAO) proposes a two year program to further advance the scientific capabilities of monolithic CMOS detectors for use as x-ray imaging spectrometers. This proposal will build upon the progress achieved with funding from a previous APRA proposal that ended in 2013. As part of that previous proposal, x- ray optimized, highly versatile, monolithic CMOS imaging detectors and technology were developed and tested. The performance and capabilities of these devices were then demonstrated, with an emphasis on the performance advantages these devices have over CCDs and other technologies. The developed SAO/SRI-Sarnoff CMOS devices incorporate: Low noise, high sensitivity ("gain") pixels; Highly parallel on-chip signal chains; Standard and very high resistivity (30,000Ohm-cm) Si; Back-Side thinning and passivation. SAO demonstrated the performance benefits of each of these features in these devices. This new proposal high-lights the performance of this previous generation of devices, and segues into new technology and capability. The high sensitivity ( 135uV/e) 6 Transistor (6T) Pinned Photo Diode (PPD) pixels provided a large charge to voltage conversion gain to the detect and resolve even small numbers of photo electrons produced by x-rays. The on-chip, parallel signal chain processed an entire row of pixels in the same time that a CCD requires to processes a single pixel. The resulting high speed operation ( 1000 times faster than CCD) provide temporal resolution while mitigating dark current and allowed room temperature operation. The high resistivity Si provided full (over) depletion for thicker devices which increased QE for higher energy x-rays. In this proposal, SAO will investigate existing NMOS and existing PMOS devices as xray imaging spectrometers. Conventional CMOS imagers are NMOS. NMOS devices collect and measure photo-electrons. In contrast, PMOS devices collect and measure photo-holes. PMOS devices have various attributes that would make them superior for use in X-ray astronomy. In particular, PMOS has: "no" photo-charge recombination; "no" Random Telegraph Signal noise (RTS); and lower read noise. The existing SRI/Sarnoff PMOS devices are small and have been developed for non-intensified night vision applications, however, no x-ray evaluation of a monolithic PMOS device has ever been made. In addition to these PMOS devices, SAO will also evaluate existing NMOS scale-able format devices that can be fabricated in any rectangular size/shape using stitchable reticles. These "Mk by Nk" devices would be ideal for large X-ray focal planes or long grating readouts. The Sarnoff/SRI Mk by Nk format devices have been designed, with foresight, so that they can be fabricated in either PMOS or NMOS by changing a single fabrication reticle and by changing the type of Si substrate. If X-ray performance results are expected, this proposal will lead the way to future fabrication of Mk by Nk PMOS devices that would be ideal for X-ray astronomy missions such as "X-ray Surveyor". SAO will also investigate the interaction of directly deposited Optical Blocking Filters (OBFs) on various back side passivated devices, and their resultant effects on very "soft" x-ray response. The latest CMOS processes and very fast on-chip, and off-chip digital readout signal chains and camera systems will be demonstrated.

MEMS Actuators for Improved Performance and Durability

NASA Astrophysics Data System (ADS)

Yearsley, James M.

Micro-ElectroMechanical Systems (MEMS) devices take advantage of force-scaling at length scales smaller than a millimeter to sense and interact with directly with phenomena and targets at the microscale. MEMS sensors found in everyday devices like cell-phones and cars include accelerometers, gyros, pressure sensors, and magnetic sensors. MEMS actuators generally serve more application specific roles including micro- and nano-tweezers used for single cell manipulation, optical switching and alignment components, and micro combustion engines for high energy density power generation. MEMS rotary motors are actuators that translate an electric drive signal into rotational motion and can serve as rate calibration inputs for gyros, stages for optical components, mixing devices for micro-fluidics, etc. Existing rotary micromotors suffer from friction and wear issues that affect lifetime and performance. Attempts to alleviate friction effects include surface treatment, magnetic and electrostatic levitation, pressurized gas bearings, and micro-ball bearings. The present work demonstrates a droplet based liquid bearing supporting a rotary micromotor that improves the operating characteristics of MEMS rotary motors. The liquid bearing provides wear-free, low-friction, passive alignment between the rotor and stator. Droplets are positioned relative to the rotor and stator through patterned superhydrophobic and hydrophilic surface coatings. The liquid bearing consists of a central droplet that acts as the motor shaft, providing axial alignment between rotor and stator, and satellite droplets, analogous to ball-bearings, that provide tip and tilt stable operation. The liquid bearing friction performance is characterized through measurement of the rotational drag coefficient and minimum starting torque due to stiction and geometric effects. Bearing operational performance is further characterized by modeling and measuring stiffness, environmental survivability, and high-speed alignment capability. The superhydrophobic coatings developed for droplet containment are also discussed and measurements of contact angle are shown to affect device performance through correlation to models of bearing friction and stiffness.

Highly Stable, Dual-Gated MoS2 Transistors Encapsulated by Hexagonal Boron Nitride with Gate-Controllable Contact, Resistance, and Threshold Voltage.

PubMed

Lee, Gwan-Hyoung; Cui, Xu; Kim, Young Duck; Arefe, Ghidewon; Zhang, Xian; Lee, Chul-Ho; Ye, Fan; Watanabe, Kenji; Taniguchi, Takashi; Kim, Philip; Hone, James

2015-07-28

Emerging two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS2) have been intensively studied because of their novel properties for advanced electronics and optoelectronics. However, 2D materials are by nature sensitive to environmental influences, such as temperature, humidity, adsorbates, and trapped charges in neighboring dielectrics. Therefore, it is crucial to develop device architectures that provide both high performance and long-term stability. Here we report high performance of dual-gated van der Waals (vdW) heterostructure devices in which MoS2 layers are fully encapsulated by hexagonal boron nitride (hBN) and contacts are formed using graphene. The hBN-encapsulation provides excellent protection from environmental factors, resulting in highly stable device performance, even at elevated temperatures. Our measurements also reveal high-quality electrical contacts and reduced hysteresis, leading to high two-terminal carrier mobility (33-151 cm(2) V(-1) s(-1)) and low subthreshold swing (80 mV/dec) at room temperature. Furthermore, adjustment of graphene Fermi level and use of dual gates enable us to separately control contact resistance and threshold voltage. This novel vdW heterostructure device opens up a new way toward fabrication of stable, high-performance devices based on 2D materials.

Validation of the Andon KD-5851 upper arm blood pressure monitor, for self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Wu, Lili; Jiao, Yinghui; Wang, Chengdong; Chen, Lei; Di, Dalin; Zhang, Haiyan

2015-08-01

This study aimed to validate the Andon KD-5851 upper arm blood pressure (BP) monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. A total of 33 eligible participants were included in the study. Sequential measurements of BPs were performed using a mercury sphygmomanometer and the device, and the data analysis was carried out following precisely the ESH-IP revision 2010. The device had 82, 98, and 99 measurements within 5, 10, and 15 mmHg for systolic blood pressure and 85, 95, and 99 measurements for diastolic blood pressure, respectively. The average device-observer difference was -0.53±4.00 mmHg for systolic blood pressure and -1.15±4.06 mmHg for diastolic blood pressure. The device passed all the criteria according to the ESH-IP revision 2010. According to the validation results on the basis of the ESH-IP revision 2010, the Andon KD-5851 upper arm BP monitor can be recommended for self/home measurement in adults. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Platform for efficient switching between multiple devices in the intensive care unit.

PubMed

De Backere, F; Vanhove, T; Dejonghe, E; Feys, M; Herinckx, T; Vankelecom, J; Decruyenaere, J; De Turck, F

2015-01-01

This article is part of the Focus Theme of METHODS of Information in Medicine on "Managing Interoperability and Complexity in Health Systems". Handheld computers, such as tablets and smartphones, are becoming more and more accessible in the clinical care setting and in Intensive Care Units (ICUs). By making the most useful and appropriate data available on multiple devices and facilitate the switching between those devices, staff members can efficiently integrate them in their workflow, allowing for faster and more accurate decisions. This paper addresses the design of a platform for the efficient switching between multiple devices in the ICU. The key functionalities of the platform are the integration of the platform into the workflow of the medical staff and providing tailored and dynamic information at the point of care. The platform is designed based on a 3-tier architecture with a focus on extensibility, scalability and an optimal user experience. After identification to a device using Near Field Communication (NFC), the appropriate medical information will be shown on the selected device. The visualization of the data is adapted to the type of the device. A web-centric approach was used to enable extensibility and portability. A prototype of the platform was thoroughly evaluated. The scalability, performance and user experience were evaluated. Performance tests show that the response time of the system scales linearly with the amount of data. Measurements with up to 20 devices have shown no performance loss due to the concurrent use of multiple devices. The platform provides a scalable and responsive solution to enable the efficient switching between multiple devices. Due to the web-centric approach new devices can easily be integrated. The performance and scalability of the platform have been evaluated and it was shown that the response time and scalability of the platform was within an acceptable range.

Invasive and non-invasive measurement in medicine and biology: calibration issues

NASA Astrophysics Data System (ADS)

Rolfe, P.; Zhang, Yan; Sun, Jinwei; Scopesi, F.; Serra, G.; Yamakoshi, K.; Tanaka, S.; Yamakoshi, T.; Yamakoshi, Y.; Ogawa, M.

2010-08-01

Invasive and non-invasive measurement sensors and systems perform vital roles in medical care. Devices are based on various principles, including optics, photonics, and plasmonics, electro-analysis, magnetics, acoustics, bio-recognition, etc. Sensors are used for the direct insertion into the human body, for example to be in contact with blood, which constitutes Invasive Measurement. This approach is very challenging technically, as sensor performance (sensitivity, response time, linearity) can deteriorate due to interactions between the sensor materials and the biological environment, such as blood or interstitial fluid. Invasive techniques may also be potentially hazardous. Alternatively, sensors or devices may be positioned external to the body surface, for example to analyse respired breath, thereby allowing safer Non-Invasive Measurement. However, such methods, which are inherently less direct, often requiring more complex calibration algorithms, perhaps using chemometric principles. This paper considers and reviews the issue of calibration in both invasive and non-invasive biomedical measurement systems. Systems in current use usually rely upon periodic calibration checks being performed by clinical staff against a variety of laboratory instruments and QC samples. These procedures require careful planning and overall management if reliable data are to be assured.

A novel interferometric characterization technique for 3D analyses at high pressures and temperatures

NASA Astrophysics Data System (ADS)

Roshanghias, Ali; Bardong, Jochen; Pulko, Jozef; Binder, Alfred

2018-04-01

Advanced optical measurement techniques are always of interest for the characterization of engineered surfaces. When pressure or temperature modules are also incorporated, these techniques will turn into robust and versatile methodologies for various applications such as performance monitoring of devices in service conditions. However, some microelectromechanical systems (MEMS) and MOEMS devices require performance monitoring at their final stage, i.e. enclosed or packaged. That necessitates measurements through a protective liquid, plastic, or glass, whereas the conventional objective lenses are not designed for such media. Correspondingly, in the current study, the development and tailoring of a 3D interferometer as a means for measuring the topography of reflective surfaces under transmissive media is sought. For topography measurements through glass, water and oil, compensation glass plates were designed and incorporated into the Michelson type interferometer objectives. Moreover, a customized chamber set-up featuring an optical access for the observation of the topographical changes at increasing pressure and temperature conditions was constructed and integrated into the apparatus. Conclusively, the in situ monitoring of the elastic deformation of sensing microstructures inside MEMS packages was achieved. These measurements were performed at a defined pressure (0–100 bar) and temperature (25 °C–180 °C).

Review of Combustion-acoustic Instabilities

NASA Technical Reports Server (NTRS)

Oyediran, Ayo; Darling, Douglas; Radhakrishnan, Krishnan

1995-01-01

Combustion-acoustic instabilities occur when the acoustic energy increase due to the unsteady heat release of the flame is greater than the losses of acoustic energy from the system. The problem of combustion-acoustic instability is a concern in many devices for various reasons, as each device may have a unique mechanism causing unsteady heat release rates and many have unique boundary conditions. To accurately predict and quantify combustion-acoustic stabilities, the unsteady heat release rate and boundary conditions need to be accurately determined. The present review brings together work performed on a variety of practical combustion devices. Many theoretical and experimental investigations of the unsteady heat release rate have been performed, some based on perturbations in the fuel delivery system particularly for rocket instabilities, while others are based on hydrodynamic processes as in ramjet dump combustors. The boundary conditions for rocket engines have been analyzed and measured extensively. However, less work has been done to measure acoustic boundary conditions in many other combustion systems.

Electrostatically Levitated Ring-Shaped Rotational-Gyro/Accelerometer

NASA Astrophysics Data System (ADS)

Murakoshi, Takao; Endo, Yasuo; Fukatsu, Keisuke; Nakamura, Sigeru; Esashi, Masayoshi

2003-04-01

This paper reports an electrostatically levitated inertia measurement system which is based on the principle of a rotational gyro. The device has several advantages: the levitation of the rotor in a vacuum eliminates mechanical friction resulting in high sensitivity; the position control for the levitation allows accelerations to be sensed in the tri-axis; and the fabrication of the device by a micromachining technique has the cost advantages afforded by miniaturization. Latest measurements yield a noise floor of the gyro and that of the accelerometer as low as 0.15 deg/h1/2 and 30 μG/Hz1/2, respectively. This performance is achieved by a new sensor design. To further improve of the previous device, a ring-shaped structure is designed and fabricated by deep reactive ion etching using inductively coupled plasma. The rotor levitation is performed with capacitive detection and electrostatic actuation. Multiaxis closed-loop control is realized by differential capacitance sensing and frequency multiplying. The rotation of the micro gyro is based on the principle of a planar variable capacitance motor.

Optimum design and measurement analysis of 0.34 THz extended interaction klystron

NASA Astrophysics Data System (ADS)

Li, Shuang; Wang, Jianguo; Xi, Hongzhu; Wang, Dongyang; Wang, Bingbing; Wang, Guangqiang; Teng, Yan

2018-02-01

In order to develop an extended interaction klystron (EIK) with high performance in the terahertz range, the staggered-tuned structure is numerically studied, manufactured, and measured. First, the circuit is optimized to get high interaction strength and avoid the mode overlapping in the output cavity, ensuring the efficiency and stability for the device. Then the clustered cavities are staggered tuned to improve its bandwidth. The particle-in-cell (PIC) code is employed to research the performances of the device under different conditions and accordingly the practicable and reliable conditions are confirmed. The device can effectively amplify the input terahertz signal and its gain reaches around 19.6 dB when the working current is 150 mA. The circuit and window are fabricated and tested, whose results demonstrate their usability. The experiment on the beam's transmission is conducted and the results show that about 92% of the emitting current can successfully arrive at the collector, ensuring the validity and feasibility for the interaction process.

Analytical Chemistry in the Regulatory Science of Medical Devices.

PubMed

Wang, Yi; Guan, Allan; Wickramasekara, Samanthi; Phillips, K Scott

2018-06-12

In the United States, regulatory science is the science of developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of all Food and Drug Administration-regulated products. Good regulatory science facilitates consumer access to innovative medical devices that are safe and effective throughout the Total Product Life Cycle (TPLC). Because the need to measure things is fundamental to the regulatory science of medical devices, analytical chemistry plays an important role, contributing to medical device technology in two ways: It can be an integral part of an innovative medical device (e.g., diagnostic devices), and it can be used to support medical device development throughout the TPLC. In this review, we focus on analytical chemistry as a tool for the regulatory science of medical devices. We highlight recent progress in companion diagnostics, medical devices on chips for preclinical testing, mass spectrometry for postmarket monitoring, and detection/characterization of bacterial biofilm to prevent infections.

Characterizing permanent magnet blocks with Helmholtz coils

NASA Astrophysics Data System (ADS)

Carnegie, D. W.; Timpf, J.

1992-08-01

Most of the insertion devices to be installed at the Advanced Photon Source will utilize permanent magnets in their magnetic structures. The quality of the spectral output is sensitive to the errors in the field of the device which are related to variations in the magnetic properties of the individual blocks. The Advanced Photon Source will have a measurement facility to map the field in the completed insertion devices and equipment to test and modify the magnetic strength of the individual magnet blocks. One component of the facility, the Helmholtz coil permanent magnet block measurement system, has been assembled and tested. This system measures the total magnetic moment vector of a block with a precision better than 0.01% and a directional resolution of about 0.05°. The design and performance of the system will be presented.

Time-Resolved Particle Image Velocimetry Measurements with Wall Shear Stress and Uncertainty Quantification for the FDA Nozzle Model.

PubMed

Raben, Jaime S; Hariharan, Prasanna; Robinson, Ronald; Malinauskas, Richard; Vlachos, Pavlos P

2016-03-01

We present advanced particle image velocimetry (PIV) processing, post-processing, and uncertainty estimation techniques to support the validation of computational fluid dynamics analyses of medical devices. This work is an extension of a previous FDA-sponsored multi-laboratory study, which used a medical device mimicking geometry referred to as the FDA benchmark nozzle model. Experimental measurements were performed using time-resolved PIV at five overlapping regions of the model for Reynolds numbers in the nozzle throat of 500, 2000, 5000, and 8000. Images included a twofold increase in spatial resolution in comparison to the previous study. Data was processed using ensemble correlation, dynamic range enhancement, and phase correlations to increase signal-to-noise ratios and measurement accuracy, and to resolve flow regions with large velocity ranges and gradients, which is typical of many blood-contacting medical devices. Parameters relevant to device safety, including shear stress at the wall and in bulk flow, were computed using radial basis functions. In addition, in-field spatially resolved pressure distributions, Reynolds stresses, and energy dissipation rates were computed from PIV measurements. Velocity measurement uncertainty was estimated directly from the PIV correlation plane, and uncertainty analysis for wall shear stress at each measurement location was performed using a Monte Carlo model. Local velocity uncertainty varied greatly and depended largely on local conditions such as particle seeding, velocity gradients, and particle displacements. Uncertainty in low velocity regions in the sudden expansion section of the nozzle was greatly reduced by over an order of magnitude when dynamic range enhancement was applied. Wall shear stress uncertainty was dominated by uncertainty contributions from velocity estimations, which were shown to account for 90-99% of the total uncertainty. This study provides advancements in the PIV processing methodologies over the previous work through increased PIV image resolution, use of robust image processing algorithms for near-wall velocity measurements and wall shear stress calculations, and uncertainty analyses for both velocity and wall shear stress measurements. The velocity and shear stress analysis, with spatially distributed uncertainty estimates, highlights the challenges of flow quantification in medical devices and provides potential methods to overcome such challenges.

Radon Assessment of Occupational Facilities, Grissom ARB, IN

DTIC Science & Technology

2012-11-28

4) EPA 402-R-92-014, Radon Measurements in Schools , July 1993 b. Measurement Device Protocols: The following protocols were used when placing...Performance Tests : A biennial performance test from commercial vendors evaluates the proficiency of USAFSAM’s radon analysis. A proficiency test ...listing of duplicates and analysis. (4) Calibration Tests : Please see Attachment 4 for calibration certificates. 3. RESULTS: In total, 106 radon monitors

Precision displacement reference system

DOEpatents

Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

2000-02-22

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

A rapid and practical technique for real-time monitoring of biomolecular interactions using mechanical responses of macromolecules

NASA Astrophysics Data System (ADS)

Tarhan, Mehmet C.; Lafitte, Nicolas; Tauran, Yannick; Jalabert, Laurent; Kumemura, Momoko; Perret, Grégoire; Kim, Beomjoon; Coleman, Anthony W.; Fujita, Hiroyuki; Collard, Dominique

2016-06-01

Monitoring biological reactions using the mechanical response of macromolecules is an alternative approach to immunoassays for providing real-time information about the underlying molecular mechanisms. Although force spectroscopy techniques, e.g. AFM and optical tweezers, perform precise molecular measurements at the single molecule level, sophisticated operation prevent their intensive use for systematic biosensing. Exploiting the biomechanical assay concept, we used micro-electro mechanical systems (MEMS) to develop a rapid platform for monitoring bio/chemical interactions of bio macromolecules, e.g. DNA, using their mechanical properties. The MEMS device provided real-time monitoring of reaction dynamics without any surface or molecular modifications. A microfluidic device with a side opening was fabricated for the optimal performance of the MEMS device to operate at the air-liquid interface for performing bioassays in liquid while actuating/sensing in air. The minimal immersion of the MEMS device in the channel provided long-term measurement stability (>10 h). Importantly, the method allowed monitoring effects of multiple solutions on the same macromolecule bundle (demonstrated with DNA bundles) without compromising the reproducibility. We monitored two different types of effects on the mechanical responses of DNA bundles (stiffness and viscous losses) exposed to pH changes (2.1 to 4.8) and different Ag+ concentrations (1 μM to 0.1 M).

Flexible and High Performance Supercapacitors Based on NiCo2O4for Wide Temperature Range Applications

NASA Astrophysics Data System (ADS)

Gupta, Ram K.; Candler, John; Palchoudhury, Soubantika; Ramasamy, Karthik; Gupta, Bipin Kumar

2015-10-01

Binder free nanostructured NiCo2O4 were grown using a facile hydrothermal technique. X-ray diffraction patterns confirmed the phase purity of NiCo2O4. The surface morphology and microstructure of the NiCo2O4 analyzed by scanning electron microscopy (SEM) showed flower-like morphology composed of needle-like structures. The potential application of binder free NiCo2O4 as an electrode for supercapacitor devices was investigated using electrochemical methods. The cyclic voltammograms of NiCo2O4 electrode using alkaline aqueous electrolytes showed the presence of redox peaks suggesting pseudocapacitance behavior. Quasi-solid state supercapacitor device fabricated by sandwiching two NiCo2O4 electrodes and separating them by ion transporting layer. The performance of the device was tested using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The device showed excellent flexibility and cyclic stability. The temperature dependent charge storage capacity was measured for their variable temperature applications. Specific capacitance of the device was enhanced by ~150% on raising the temperature from 20 to 60 °C. Hence, the results suggest that NiCo2O4 grown under these conditions could be a suitable material for high performance supercapacitor devices that can be operated at variable temperatures.

Flexible and High Performance Supercapacitors Based on NiCo2O4for Wide Temperature Range Applications.

PubMed

Gupta, Ram K; Candler, John; Palchoudhury, Soubantika; Ramasamy, Karthik; Gupta, Bipin Kumar

2015-10-20

Binder free nanostructured NiCo2O4 were grown using a facile hydrothermal technique. X-ray diffraction patterns confirmed the phase purity of NiCo2O4. The surface morphology and microstructure of the NiCo2O4 analyzed by scanning electron microscopy (SEM) showed flower-like morphology composed of needle-like structures. The potential application of binder free NiCo2O4 as an electrode for supercapacitor devices was investigated using electrochemical methods. The cyclic voltammograms of NiCo2O4 electrode using alkaline aqueous electrolytes showed the presence of redox peaks suggesting pseudocapacitance behavior. Quasi-solid state supercapacitor device fabricated by sandwiching two NiCo2O4 electrodes and separating them by ion transporting layer. The performance of the device was tested using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The device showed excellent flexibility and cyclic stability. The temperature dependent charge storage capacity was measured for their variable temperature applications. Specific capacitance of the device was enhanced by ~150% on raising the temperature from 20 to 60 °C. Hence, the results suggest that NiCo2O4 grown under these conditions could be a suitable material for high performance supercapacitor devices that can be operated at variable temperatures.

Flexible and High Performance Supercapacitors Based on NiCo2O4for Wide Temperature Range Applications

PubMed Central

Gupta, Ram K.; Candler, John; Palchoudhury, Soubantika; Ramasamy, Karthik; Gupta, Bipin Kumar

2015-01-01

Binder free nanostructured NiCo2O4 were grown using a facile hydrothermal technique. X-ray diffraction patterns confirmed the phase purity of NiCo2O4. The surface morphology and microstructure of the NiCo2O4 analyzed by scanning electron microscopy (SEM) showed flower-like morphology composed of needle-like structures. The potential application of binder free NiCo2O4 as an electrode for supercapacitor devices was investigated using electrochemical methods. The cyclic voltammograms of NiCo2O4 electrode using alkaline aqueous electrolytes showed the presence of redox peaks suggesting pseudocapacitance behavior. Quasi-solid state supercapacitor device fabricated by sandwiching two NiCo2O4 electrodes and separating them by ion transporting layer. The performance of the device was tested using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The device showed excellent flexibility and cyclic stability. The temperature dependent charge storage capacity was measured for their variable temperature applications. Specific capacitance of the device was enhanced by ~150% on raising the temperature from 20 to 60 °C. Hence, the results suggest that NiCo2O4 grown under these conditions could be a suitable material for high performance supercapacitor devices that can be operated at variable temperatures. PMID:26482921

Cardiopulmonary resuscitation using the cardio vent device in a resuscitation model.

PubMed

Suner, Selim; Jay, Gregory D; Kleinman, Gary J; Woolard, Robert H; Jagminas, Liudvikas; Becker, Bruce M

2002-05-01

To compare the "Bellows on Sternum Resuscitation" (BSR) device that permits simultaneous compression and ventilation by one rescuer with two person cardiopulmonary resuscitation (CPR) with bag-valve-mask (BVM) ventilation in a single blind crossover study performed in the laboratory setting. Tidal volume and compression depth were recorded continuously during 12-min CPR sessions with the BSR device and two person CPR. Six CPR instructors performed a total of 1,894 ventilations and 10,532 compressions in 3 separate 12-min sessions. Mean tidal volume (MTV) and compression rate (CR) with the BSR device differed significantly from CPR with the BVM group (1242 mL vs. 1065 mL, respectively, p = 0.0018 and 63.2 compressions per minute (cpm) vs. 81.3 cpm, respectively, p = 0.0076). Error in compression depth (ECD) rate of 9.78% was observed with the BSR device compared to 8.49% with BMV CPR (p = 0.1815). Error rate was significantly greater during the second half of CPR sessions for both BSR and BVM groups. It is concluded that one-person CPR with the BSR device is equivalent to two-person CPR with BVM in all measured parameters except for CR. Both groups exhibited greater error rate in CPR performance in the latter half of 12-min CPR sessions.

Cryogenic probe station for use in automated microwave and noise figure measurements

NASA Technical Reports Server (NTRS)

Taub, Susan R.; Alterovitz, Samuel A.; Young, Paul G.; Ebihara, Ben T.; Romanofsky, Robert R.

1994-01-01

A cryogenic measurement system capable of performing on-wafer RF testing of semiconductor devices and circuits has been developed. This 'CryoProbe Station' can wafer-probe devices and circuits at cryogenic temperatures, thus eliminating the need for wire bonds. The system operates under vacuum created by a sorption pump. It uses an open cycle cooling system that can be cooled with either liquid nitrogen or liquid helium. Presently, it can reach temperatures, as low as 80 K and 37 K for each of the coolants, respectively. The temperature can be raised using a heater and it is stabilized to within 0.2 K by use of a temperature controller. The CryoProbe Station features a 1 by 2 inch stage that can hold large circuits and calibration standards simultaneously. The system is used with a Hewlett Packard 8510C Automatic Network Analyzer (ANA) to obtain S-parameter data over the frequency range 0.045-26.5 GHz. S-parameter data on HEMT (high electron mobility transistors) devices has been obtained with this station. With the use of DEEMBED software from NIST, detailed transmission line studies have been performed. Although the CryoProbe Station is designed for frequencies up to 26.5 GHz, useful transmission line data has been obtained for frequencies as high as 40 GHz. The CryoProbe station has also been used with the ATN noise figure measurement system to perform automatic, temperature dependent noise figure measurements.

Virtual Environment TBI Screen (VETS)

DTIC Science & Technology

2014-10-01

balance challenges performed on a modified Wii Balance Board . Implementation of this device will enhance current approaches in TBI and mild TBI (i.e...TBI) screen (VETS) device in measuring standing balance . This system consists of software, a Wii balance board , and a large screen television that...Validate Wii ™ Balance Board relative to NeuroCom forceplate ! Running Wii Balance Board validation protocol. ! Milestone Achieved:

Enhanced stability of ZnO-based inverted organic photovoltaic devices by phosphonic acid modification

NASA Astrophysics Data System (ADS)

MacLeod, Bradley; Tremolet de Villers, Bertrand; Cowan, Sarah; Ratcliff, Erin; Olson, Dana

2014-03-01

Solution-processed ZnO thin films are now commonly used as n-type bottom contacts in inverted-geometry organic photovoltaics (OPVs). The use of ZnO eliminates the need for highly-reactive top-contact (air-interface) electrode material, such as calcium and aluminum which are commonly used in conventional geometries, which enables operational lifetimes of unencapsulated devices to shift from minutes or hours to days. Modification of the ZnO film by self-assembled monolayers (SAMs) has been shown to enhance performance as well as air-stability during storage. We modify ZnO with dipolar phosphonic acids and observe enhanced performance and stability. We show for the first time devices measured under continuous illumination at one-sun intensity which have significantly enhanced stability when utilizing SAM-modified ZnO. These continuous-illumination stability measurements allow us to investigate the degradation mechanisms of these more stable inverted OPV devices. This work was was supported by of the Center for Interface Science: Solar Electric Materials (CISSEM), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001084.

Dual Transition Edge Sensor Bolometer for Enhanced Dynamic Range

NASA Technical Reports Server (NTRS)

Chervenak, J. A.; Benford, D. J.; Moseley, S. H.; Irwin, K. D.

2004-01-01

Broadband surveys at the millimeter and submillimeter wavelengths will require bolometers that can reach new limits of sensitivity and also operate under high background conditions. To address this need, we present results on a dual transition edge sensor (TES) device with two operating modes: one for low background, ultrasensitive detection and one for high background, enhanced dynamic range detection. The device consists of a detector element with two transition temperatures (T(sub c)) of 0.25 and 0.51 K located on the same micromachined, thermally isolated membrane structure. It can be biased on either transition, and features phonon-limited noise performance at the lower T(sub c). We measure noise performance on the lower transition 7 x 10(exp -18) W/rt(Hz) and the bias power on the upper transition of 12.5 pW, giving a factor of 10 enhancement of the dynamic range for the device. We discuss the biasable range of this type of device and present a design concept to optimize utility of the device.

Multi-Axis Force Sensor for Human-Robot Interaction Sensing in a Rehabilitation Robotic Device.

PubMed

Grosu, Victor; Grosu, Svetlana; Vanderborght, Bram; Lefeber, Dirk; Rodriguez-Guerrero, Carlos

2017-06-05

Human-robot interaction sensing is a compulsory feature in modern robotic systems where direct contact or close collaboration is desired. Rehabilitation and assistive robotics are fields where interaction forces are required for both safety and increased control performance of the device with a more comfortable experience for the user. In order to provide an efficient interaction feedback between the user and rehabilitation device, high performance sensing units are demanded. This work introduces a novel design of a multi-axis force sensor dedicated for measuring pelvis interaction forces in a rehabilitation exoskeleton device. The sensor is conceived such that it has different sensitivity characteristics for the three axes of interest having also movable parts in order to allow free rotations and limit crosstalk errors. Integrated sensor electronics make it easy to acquire and process data for a real-time distributed system architecture. Two of the developed sensors are integrated and tested in a complex gait rehabilitation device for safe and compliant control.

Accelerometer-based on-body sensor localization for health and medical monitoring applications

PubMed Central

Vahdatpour, Alireza; Amini, Navid; Xu, Wenyao; Sarrafzadeh, Majid

2011-01-01

In this paper, we present a technique to recognize the position of sensors on the human body. Automatic on-body device localization ensures correctness and accuracy of measurements in health and medical monitoring systems. In addition, it provides opportunities to improve the performance and usability of ubiquitous devices. Our technique uses accelerometers to capture motion data to estimate the location of the device on the user’s body, using mixed supervised and unsupervised time series analysis methods. We have evaluated our technique with extensive experiments on 25 subjects. On average, our technique achieves 89% accuracy in estimating the location of devices on the body. In order to study the feasibility of classification of left limbs from right limbs (e.g., left arm vs. right arm), we performed analysis, based of which no meaningful classification was observed. Personalized ultraviolet monitoring and wireless transmission power control comprise two immediate applications of our on-body device localization approach. Such applications, along with their corresponding feasibility studies, are discussed. PMID:22347840

Virtex-II Pro SEE Test Methods and Results

NASA Technical Reports Server (NTRS)

Petrick, David; Powell, Wesley; Howard, James W., Jr.; LaBel, Kenneth A.

2004-01-01

The objective of this coarse Single Event Effect (SEE) test is to determine the suitability of the commercial Virtex-II Pro family for use in spaceflight applications. To this end, this test is primarily intended to determine any Singe Event Latchup (SEL) susceptibilities for these devices. Secondly, this test is intended to measure the level of Single Event Upset (SEU) susceptibilities and in a general sense where they occur. The coarse SEE test was performed on a commercial XC2VP7 device, a relatively small single processor version of the Virtex-II Pro. As the XC2VP7 shares the same functional block design and fabrication process with the larger Virtex-II Pro devices, the results of this test should also be applicable to the larger devices. The XC2VP7 device was tested on a commercial Virtex-II Pro development board. The testing was performed at the Cyclotron laboratories at Texas A&M and Michigan State Universities using ions of varying energy levels and fluences.

Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance

NASA Technical Reports Server (NTRS)

Morris, C. I.

2003-01-01

Pulse detonation engines (PDB) have generated considerable research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional gas turbines and rocket engines. The detonative mode of combustion employed by these devices offers a theoretical thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional engines. However, the unsteady blowdown process intrinsic to all pulse detonation devices has made realistic estimates of the actual propulsive performance of PDES problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models.

CCD charge collection efficiency and the photon transfer technique

NASA Technical Reports Server (NTRS)

Janesick, J.; Klaasen, K.; Elliott, T.

1985-01-01

The charge-coupled device (CCD) has shown unprecendented performance as a photon detector in the areas of spectral response, charge transfer, and readout noise. Recent experience indicates, however, that the full potential for the CCD's charge collection efficiency (CCE) lies well beyond that which is realized in currently available devices. A definition of CCE performance is presented and a standard test tool (the photon transfer technique) for measuring and optimizing this important CCD parameter is introduced. CCE characteristics for different types of CCDs are compared; the primary limitations in achieving high CCE performance are discussed, and the prospects for future improvement are outlined.

Reflectance Spectroscopy | Photovoltaic Research | NREL

Science.gov Websites

Reflectance Spectroscopy Reflectance Spectroscopy In a fraction of a second, the photovoltaic (PV metallization properties. PV Research Other Measurements pages: Device Performance Analytical Microscopy & directly normal. The reflectance measurement uses a principle of reciprocity Schematic of the PV

Performance Evaluation Methods for Assistive Robotic Technology

NASA Astrophysics Data System (ADS)

Tsui, Katherine M.; Feil-Seifer, David J.; Matarić, Maja J.; Yanco, Holly A.

Robots have been developed for several assistive technology domains, including intervention for Autism Spectrum Disorders, eldercare, and post-stroke rehabilitation. Assistive robots have also been used to promote independent living through the use of devices such as intelligent wheelchairs, assistive robotic arms, and external limb prostheses. Work in the broad field of assistive robotic technology can be divided into two major research phases: technology development, in which new devices, software, and interfaces are created; and clinical, in which assistive technology is applied to a given end-user population. Moving from technology development towards clinical applications is a significant challenge. Developing performance metrics for assistive robots poses a related set of challenges. In this paper, we survey several areas of assistive robotic technology in order to derive and demonstrate domain-specific means for evaluating the performance of such systems. We also present two case studies of applied performance measures and a discussion regarding the ubiquity of functional performance measures across the sampled domains. Finally, we present guidelines for incorporating human performance metrics into end-user evaluations of assistive robotic technologies.

Design and modeling of a measuring device for a TIR-R concentrator

NASA Astrophysics Data System (ADS)

Calero, Daniel Pérez; Miñano, Juan Carlos; Benitez, Pablo; Hernandez, Maikel; Cvetkovic, Aleksandra

2006-08-01

One of the most usual procedures to measure a concentrator optical efficiency is by direct comparison between the photocurrent generated by the compound concentrator/solar cell and photocurrent that single cell would generate under identical radiation conditions. Unfortunately, such procedure can give a good idea of the generator final performance, but can not indicate the real amount of radiation that will impinge over the cell. This apparent contradiction is based on the fact that once the cell is coupled with the concentrator, rays incidence is not perpendicular, but highly oblique, with an angle that can reach 70 ° or even greater for high concentration devices. The antireflective coating of the cell does not perform well enough for the whole incidence angle and frequency ranges because low cost is other important requirement for the solar cells. In consequence, the generated photocurrent drops for large incidence angles. In our case, a 70% incidence angle could, in the worst case, mean a 34% loss on generated photocurrent. With the aim of correcting such problem a special device has been designed in the framework of a EU funded project called HAMLET. The concept of the device is to substitute the concentrator receptor by a system formed by an optical collimator that would reduce concentration and incidence angle, and a characterized solar cell. The paper gives the results of this measuring procedure.

New generation of wearable goniometers for motion capture systems

PubMed Central

2014-01-01

Background Monitoring joint angles through wearable systems enables human posture and gesture to be reconstructed as a support for physical rehabilitation both in clinics and at the patient’s home. A new generation of wearable goniometers based on knitted piezoresistive fabric (KPF) technology is presented. Methods KPF single-and double-layer devices were designed and characterized under stretching and bending to work as strain sensors and goniometers. The theoretical working principle and the derived electromechanical model, previously proved for carbon elastomer sensors, were generalized to KPF. The devices were used to correlate angles and piezoresistive fabric behaviour, to highlight the differences in terms of performance between the single layer and the double layer sensors. A fast calibration procedure is also proposed. Results The proposed device was tested both in static and dynamic conditions in comparison with standard electrogoniometers and inertial measurement units respectively. KPF goniometer capabilities in angle detection were experimentally proved and a discussion of the device measurement errors of is provided. The paper concludes with an analysis of sensor accuracy and hysteresis reduction in particular configurations. Conclusions Double layer KPF goniometers showed a promising performance in terms of angle measurements both in quasi-static and dynamic working mode for velocities typical of human movement. A further approach consisting of a combination of multiple sensors to increase accuracy via sensor fusion technique has been presented. PMID:24725669

Validity and Reliability of the PUSH Wearable Device to Measure Movement Velocity During the Back Squat Exercise.

PubMed

Balsalobre-Fernández, Carlos; Kuzdub, Matt; Poveda-Ortiz, Pedro; Campo-Vecino, Juan Del

2016-07-01

Balsalobre-Fernández, C, Kuzdub, M, Poveda-Ortiz, P, and Campo-Vecino, Jd. Validity and reliability of the PUSH wearable device to measure movement velocity during the back squat exercise. J Strength Cond Res 30(7): 1968-1974, 2016-The purpose of this study was to analyze the validity and reliability of a wearable device to measure movement velocity during the back squat exercise. To do this, 10 recreationally active healthy men (age = 23.4 ± 5.2 years; back squat 1 repetition maximum [1RM] = 83 ± 8.2 kg) performed 3 repetitions of the back squat exercise with 5 different loads ranging from 25 to 85% 1RM on a Smith Machine. Movement velocity for each of the total 150 repetitions was simultaneously recorded using the T-Force linear transducer (LT) and the PUSH wearable band. Results showed a high correlation between the LT and the wearable device mean (r = 0.85; standard error of estimate [SEE] = 0.08 m·s) and peak velocity (r = 0.91, SEE = 0.1 m·s). Moreover, there was a very high agreement between these 2 devices for the measurement of mean (intraclass correlation coefficient [ICC] = 0.907) and peak velocity (ICC = 0.944), although a systematic bias between devices was observed (PUSH peak velocity being -0.07 ± 0.1 m·s lower, p ≤ 0.05). When measuring the 3 repetitions with each load, both devices displayed almost equal reliability (Test-retest reliability: LT [r = 0.98], PUSH [r = 0.956]; ICC: LT [ICC = 0.989], PUSH [ICC = 0.981]; coefficient of variation [CV]: LT [CV = 4.2%], PUSH [CV = 5.0%]). Finally, individual load-velocity relationships measured with both the LT (R = 0.96) and the PUSH wearable device (R = 0.94) showed similar, very high coefficients of determination. In conclusion, these results support the use of an affordable wearable device to track velocity during back squat training. Wearable devices, such as the one in this study, could have valuable practical applications for strength and conditioning coaches.

The use of hearing protection devices by older adults during recreational noise exposure.

PubMed

Nondahl, D M; Cruickshanks, K J; Dalton, D S; Klein, B E K; Klein, R; Tweed, T S; Wiley, T L

2006-01-01

A population-based study to assess the use of hearing protection devices by older adults during noisy recreational activities was performed. The population-based Epidemiology of Hearing Loss Study was designed to measure the prevalence of hearing loss in adults residing in Beaver Dam, Wisconsin. The use of hearing protection devices during noisy recreational activities was assessed by performing three examinations over a period of 10 years (1993-1995, no. of participants (n)=3753, aged 48-92 years; 1998-2000, n=2800, aged 53-97 years; 2003-2005, n=2395, aged 58-100 years). The recreational activities included hunting, target shooting, woodworking/carpentry, metalworking, driving loud recreational vehicles, and performing yard work using either power tools or a chain saw. The prevalence of using hearing protection devices during any of these activities increased with time (9.5%, 15.0%, and 19.9% at baseline, 5 years, and 10 years, respectively). However, the use of hearing protection devices remained low for most activities. Those under the age of 65 were twice as likely to use hearing protection devices during noisy activities than were older adults. Men, those with a hearing handicap, and those with significant tinnitus were more likely to use hearing protection devices. Smokers and the less educated were less likely to use hearing protection devices. The results demonstrated that many adults expose themselves to potentially damaging recreational noise, leaving them at risk for hearing loss.

Magnetoresistive sensors based on the elasticity of domain walls.

PubMed

Zhang, Xueying; Vernier, Nicolas; Cao, Zhiqiang; Leng, Qunwen; Cao, Anni; Ravelosona, Dafine; Zhao, Weisheng

2018-06-19

Magnetic sensors based on the magnetoresistance effects have a promising application prospect due to their excellent sensitivity and advantages in terms of the integration. However, competition between higher sensitivity and larger measuring range remains a problem. Here, we propose a novel mechanism for the design of magnetoresistive sensors: probing the perpendicular field by detecting the expansion of the elastic magnetic Domain Wall (DW) in the free layer of a spin valve or a magnetic tunnel junction. Performances of devices based on this mechanism, such as the sensitivity and the measuring range can be tuned by manipulating the geometry of the device, without changing the intrinsic properties of the material, thus promising a higher integration level and a better performance. The mechanism is theoretically explained based on the experimental results. Two examples are proposed and their functionality and performances are verified via micromagnetic simulation. © 2018 IOP Publishing Ltd.

Field evaluation of a prototype paper-based point-of-care fingerstick transaminase test.

PubMed

Pollock, Nira R; McGray, Sarah; Colby, Donn J; Noubary, Farzad; Nguyen, Huyen; Nguyen, The Anh; Khormaee, Sariah; Jain, Sidhartha; Hawkins, Kenneth; Kumar, Shailendra; Rolland, Jason P; Beattie, Patrick D; Chau, Nguyen V; Quang, Vo M; Barfield, Cori; Tietje, Kathy; Steele, Matt; Weigl, Bernhard H

2013-01-01

Monitoring for drug-induced liver injury (DILI) via serial transaminase measurements in patients on potentially hepatotoxic medications (e.g., for HIV and tuberculosis) is routine in resource-rich nations, but often unavailable in resource-limited settings. Towards enabling universal access to affordable point-of-care (POC) screening for DILI, we have performed the first field evaluation of a paper-based, microfluidic fingerstick test for rapid, semi-quantitative, visual measurement of blood alanine aminotransferase (ALT). Our objectives were to assess operational feasibility, inter-operator variability, lot variability, device failure rate, and accuracy, to inform device modification for further field testing. The paper-based ALT test was performed at POC on fingerstick samples from 600 outpatients receiving HIV treatment in Vietnam. Results, read independently by two clinic nurses, were compared with gold-standard automated (Roche Cobas) results from venipuncture samples obtained in parallel. Two device lots were used sequentially. We demonstrated high inter-operator agreement, with 96.3% (95% C.I., 94.3-97.7%) agreement in placing visual results into clinically-defined "bins" (<3x, 3-5x, and >5x upper limit of normal), >90% agreement in validity determination, and intraclass correlation coefficient of 0.89 (95% C.I., 0.87-0.91). Lot variability was observed in % invalids due to hemolysis (21.1% for Lot 1, 1.6% for Lot 2) and correlated with lots of incorporated plasma separation membranes. Invalid rates <1% were observed for all other device controls. Overall bin placement accuracy for the two readers was 84% (84.3%/83.6%). Our findings of extremely high inter-operator agreement for visual reading-obtained in a target clinical environment, as performed by local practitioners-indicate that the device operation and reading process is feasible and reproducible. Bin placement accuracy and lot-to-lot variability data identified specific targets for device optimization and material quality control. This is the first field study performed with a patterned paper-based microfluidic device and opens the door to development of similar assays for other important analytes.

A Study on Performance and Safety Tests of Defibrillator Equipment.

PubMed

Tavakoli Golpaygani, A; Movahedi, M M; Reza, M

2017-12-01

Nowadays, more than 10,000 different types of medical devices can be found in hospitals. This way, medical electrical equipment is being employed in a wide variety of fields in medical sciences with different physiological effects and measurements. Hospitals and medical centers must ensure that their critical medical devices are safe, accurate, reliable and operational at the required level of performance. Defibrillators are critical resuscitation devices. The use of reliable defibirillators has led to more effective treatments and improved patient safety through better control and management of complications during Cardiopulmonary Resuscitation (CPR). The metrological reliability of twenty frequent use, manual defibrillators in use ten hospitals (4 private and 6 public) in one of the provinces of Iran according to international and national standards was evaluated. Quantitative analysis of control and instrument accuracy showed the amount of the obtained results in many units are critical which had less value over the standard limitations especially in devices with poor battery. For the accuracy of delivered energy analysis, only twelve units delivered acceptable output values and the precision in the output energy measurements especialy in weak battry condition, after activation of discharge alarm, were low. Obtained results indicate a need for new and severe regulations on periodic performance verifications and medical equipment quality control program especially for high risk instruments. It is also necessary to provide training courses on the fundumentals of operation and performane parameters for medical staff in the field of meterology in medicine and how one can get good accuracy results especially in high risk medical devices.

A Study on Performance and Safety Tests of Defibrillator Equipment

PubMed Central

Tavakoli Golpaygani, A.; Movahedi, M.M.; Reza, M.

2017-01-01

Introduction: Nowadays, more than 10,000 different types of medical devices can be found in hospitals. This way, medical electrical equipment is being employed in a wide variety of fields in medical sciences with different physiological effects and measurements. Hospitals and medical centers must ensure that their critical medical devices are safe, accurate, reliable and operational at the required level of performance. Defibrillators are critical resuscitation devices. The use of reliable defibirillators has led to more effective treatments and improved patient safety through better control and management of complications during Cardiopulmonary Resuscitation (CPR). Materials and Methods: The metrological reliability of twenty frequent use, manual defibrillators in use ten hospitals (4 private and 6 public) in one of the provinces of Iran according to international and national standards was evaluated. Results: Quantitative analysis of control and instrument accuracy showed the amount of the obtained results in many units are critical which had less value over the standard limitations especially in devices with poor battery. For the accuracy of delivered energy analysis, only twelve units delivered acceptable output values and the precision in the output energy measurements especialy in weak battry condition, after activation of discharge alarm, were low. Conclusion: Obtained results indicate a need for new and severe regulations on periodic performance verifications and medical equipment quality control program especially for high risk instruments. It is also necessary to provide training courses on the fundumentals of operation and performane parameters for medical staff in the field of meterology in medicine and how one can get good accuracy results especially in high risk medical devices. PMID:29445716

Proof of Concept: Design and Initial Evaluation of a Device to Measure Gastrointestinal Transit Time.

PubMed

Wagner, Robert H; Savir-Baruch, Bital; Halama, James R; Venu, Mukund; Gabriel, Medhat S; Bova, Davide

2017-09-01

Chronic constipation and gastrointestinal motility disorders constitute a large part of a gastroenterology practice and have a significant impact on a patient's quality of life and lifestyle. In most cases, medications are prescribed to alleviate symptoms without there being an objective measurement of response. Commonly used investigations of gastrointestinal transit times are currently limited to radiopaque markers or electronic capsules. Repeated use of these techniques is limited because of the radiation exposure and the significant cost of the devices. We present the proof of concept for a new device to measure gastrointestinal transit time using commonly available and inexpensive materials with only a small amount of radiotracer. Methods: We assembled gelatin capsules containing a 67 Ga-citrate-radiolabeled grain of rice embedded in paraffin for use as a point-source transit device. It was tested for stability in vitro and subsequently was given orally to 4 healthy volunteers and 10 patients with constipation or diarrhea. Imaging was performed at regular intervals until the device was excreted. Results: The device remained intact and visible as a point source in all subjects until excretion. When used along with a diary of bowel movement times and dates, the device could determine the total transit time. The device could be visualized either alone or in combination with a barium small-bowel follow-through study or a gastric emptying study. Conclusion: The use of a point-source transit device for the determination of gastrointestinal transit time is a feasible alternative to other methods. The device is inexpensive and easy to assemble, requires only a small amount of radiotracer, and remains inert throughout the gastrointestinal tract, allowing for accurate determination of gastrointestinal transit time. Further investigation of the device is required to establish optimum imaging parameters and reference values. Measurements of gastrointestinal transit time may be useful in managing patients with dysmotility and in selecting the appropriate pharmaceutical treatment. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Design of an omnidirectional single-point photodetector for large-scale spatial coordinate measurement

NASA Astrophysics Data System (ADS)

Xie, Hongbo; Mao, Chensheng; Ren, Yongjie; Zhu, Jigui; Wang, Chao; Yang, Lei

2017-10-01

In high precision and large-scale coordinate measurement, one commonly used approach to determine the coordinate of a target point is utilizing the spatial trigonometric relationships between multiple laser transmitter stations and the target point. A light receiving device at the target point is the key element in large-scale coordinate measurement systems. To ensure high-resolution and highly sensitive spatial coordinate measurement, a high-performance and miniaturized omnidirectional single-point photodetector (OSPD) is greatly desired. We report one design of OSPD using an aspheric lens, which achieves an enhanced reception angle of -5 deg to 45 deg in vertical and 360 deg in horizontal. As the heart of our OSPD, the aspheric lens is designed in a geometric model and optimized by LightTools Software, which enables the reflection of a wide-angle incident light beam into the single-point photodiode. The performance of home-made OSPD is characterized with working distances from 1 to 13 m and further analyzed utilizing developed a geometric model. The experimental and analytic results verify that our device is highly suitable for large-scale coordinate metrology. The developed device also holds great potential in various applications such as omnidirectional vision sensor, indoor global positioning system, and optical wireless communication systems.

Performance evaluation of an infrared thermocouple.

PubMed

Chen, Chiachung; Weng, Yu-Kai; Shen, Te-Ching

2010-01-01

The measurement of the leaf temperature of forests or agricultural plants is an important technique for the monitoring of the physiological state of crops. The infrared thermometer is a convenient device due to its fast response and nondestructive measurement technique. Nowadays, a novel infrared thermocouple, developed with the same measurement principle of the infrared thermometer but using a different detector, has been commercialized for non-contact temperature measurement. The performances of two-kinds of infrared thermocouples were evaluated in this study. The standard temperature was maintained by a temperature calibrator and a special black cavity device. The results indicated that both types of infrared thermocouples had good precision. The error distribution ranged from -1.8 °C to 18 °C as the reading values served as the true values. Within the range from 13 °C to 37 °C, the adequate calibration equations were the high-order polynomial equations. Within the narrower range from 20 °C to 35 °C, the adequate equation was a linear equation for one sensor and a two-order polynomial equation for the other sensor. The accuracy of the two kinds of infrared thermocouple was improved by nearly 0.4 °C with the calibration equations. These devices could serve as mobile monitoring tools for in situ and real time routine estimation of leaf temperatures.

Detection of gas leakage

DOEpatents

Thornberg, Steven [Peralta, NM; Brown, Jason [Albuquerque, NM

2012-06-19

A method of detecting leaks and measuring volumes as well as an apparatus, the Power-free Pump Module (PPM), that is a self-contained leak test and volume measurement apparatus that requires no external sources of electrical power during leak testing or volume measurement, where the invention is a portable, pneumatically-controlled instrument capable of generating a vacuum, calibrating volumes, and performing quantitative leak tests on a closed test system or device, all without the use of alternating current (AC) power. Capabilities include the ability is to provide a modest vacuum (less than 10 Torr), perform a pressure rise leak test, measure the gas's absolute pressure, and perform volume measurements. All operations are performed through a simple rotary control valve which controls pneumatically-operated manifold valves.

Fuzzy logic modeling of high performance rechargeable batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, P.; Fennie, C. Jr.; Reisner, D.E.

1998-07-01

Accurate battery state-of-charge (SOC) measurements are critical in many portable electronic device applications. Yet conventional techniques for battery SOC estimation are limited in their accuracy, reliability, and flexibility. In this paper the authors present a powerful new approach to estimate battery SOC using a fuzzy logic-based methodology. This approach provides a universally applicable, accurate method for battery SOC estimation either integrated within, or as an external monitor to, an electronic device. The methodology is demonstrated in modeling impedance measurements on Ni-MH cells and discharge voltage curves of Li-ion cells.

Low-cost, portable open-source gas monitoring device based on chemosensory technology

NASA Astrophysics Data System (ADS)

Gotor, Raúl; Gaviña, Pablo; Costero, Ana M.

2015-08-01

We report herein the construction of an electronic device to perform the real-time digitalization of the color state of the optical chemosensors used in the detection of dangerous gases. To construct the device, we used open-source modular electronics, such as Arduino and Sparkfun components, as well as free and open-source software (FOSS). The basic principle of the operation of this device is the continuous color measurement of a chemosensor-doped sensing film, whose color changes in the presence of a specific gas. The chemosensor-sensing film can be prepared by using any of the widely available chemosensors for the desired gas. Color measurement is taken by two TCS230 color sensor ICs, reported to the microcontroller, and the results are displayed on an LCD display and pushed through a USB serial port. By using a cyanide optical chemosensor, we demonstrated the operation of the device as a HCN gas detector at low concentrations.

Precision Continuum Receivers for Astrophysical Applications

NASA Technical Reports Server (NTRS)

Wollack, Edward J.

2011-01-01

Cryogenically cooled HEMT (High Electron Mobility Transistor) amplifiers find widespread use in radioastronomy receivers. In recent years, these devices have also been commonly employed in broadband receivers for precision measurements of the Cosmic Microwave Background (CMB) radiation. In this setting, the combination of ultra-low-noise and low-spectral-resolution observations reinforce the importance achieving suitable control over the device environment to achieve fundamentally limited receiver performance. The influence of the intrinsic amplifier stability at low frequencies on data quality (e.g., achievable noise and residual temporal correlations), observational and calibration strategies, as well as architectural mitigation approaches in this setting will be discussed. The implications of device level 1/f fluctuations reported in the literature on system performance will be reviewed.

Integrating Nanostructured Artificial Receptors with Whispering Gallery Mode Optical Microresonators via Inorganic Molecular Imprinting Techniques

PubMed Central

Hammond, G. Denise; Vojta, Adam L.; Grant, Sheila A.; Hunt, Heather K.

2016-01-01

The creation of label-free biosensors capable of accurately detecting trace contaminants, particularly small organic molecules, is of significant interest for applications in environmental monitoring. This is achieved by pairing a high-sensitivity signal transducer with a biorecognition element that imparts selectivity towards the compound of interest. However, many environmental pollutants do not have corresponding biorecognition elements. Fortunately, biomimetic chemistries, such as molecular imprinting, allow for the design of artificial receptors with very high selectivity for the target. Here, we perform a proof-of-concept study to show how artificial receptors may be created from inorganic silanes using the molecular imprinting technique and paired with high-sensitivity transducers without loss of device performance. Silica microsphere Whispering Gallery Mode optical microresonators are coated with a silica thin film templated by a small fluorescent dye, fluorescein isothiocyanate, which serves as our model target. Oxygen plasma degradation and solvent extraction of the template are compared. Extracted optical devices are interacted with the template molecule to confirm successful sorption of the template. Surface characterization is accomplished via fluorescence and optical microscopy, ellipsometry, optical profilometry, and contact angle measurements. The quality factors of the devices are measured to evaluate the impact of the coating on device sensitivity. The resulting devices show uniform surface coating with no microstructural damage with Q factors above 106. This is the first report demonstrating the integration of these devices with molecular imprinting techniques, and could lead to new routes to biosensor creation for environmental monitoring. PMID:27314397

In-situ comprehensive calibration of a tri-port nano-electro-mechanical device.

PubMed

Collin, E; Defoort, M; Lulla, K; Moutonet, T; Heron, J-S; Bourgeois, O; Bunkov, Yu M; Godfrin, H

2012-04-01

We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very nonlinear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasi-linear) output velocity port. We present an experimental method enabling a full characterization of the nanomechanical device harmonic response: the nonlinear capacitance function C(x) is derived, and the normal parameters k and m (spring constant and mass) of the mode under study are measured through a careful definition of the motion (in meters) and of the applied forces (in Newtons). These results are obtained with a series of purely electric measurements performed without disconnecting/reconnecting the device, and rely only on known dc properties of the circuit, making use of a thermometric property of the oscillator itself: we use the Young modulus of the coating metal as a thermometer, and the resistivity for Joule heating. The setup requires only three connecting lines without any particular matching, enabling the preservation of a high impedance NEMS environment even at MHz frequencies. The experimental data are fit to a detailed electrical and thermal model of the NEMS device, demonstrating a complete understanding of its dynamics. These methods are quite general and can be adapted (as a whole, or in parts) to a large variety of electromechanical devices. © 2012 American Institute of Physics

Silicon insulator-based dielectrophoresis devices for minimized heating effects.

PubMed

Zellner, Phillip; Agah, Masoud

2012-08-01

Concentration of biological specimens that are extremely dilute in a solution is of paramount importance for their detection. Microfluidic chips based on insulator-based DEP (iDEP) have been used to selectively concentrate bacteria and viruses. iDEP biochips are currently fabricated with glass or polymer substrates to allow for high electric fields within the channels. Joule heating is a well-known problem in these substrates and can lead to decreased throughput and even device failure. In this work, we present, for the first time, highly efficient trapping and separation of particles in DC iDEP devices that are fabricated on silicon using a single-etch-step three-dimensional microfabrication process with greatly improved heat dissipation properties. Fabrication in silicon allows for greater heat dissipation for identical geometries and operating conditions. The 3D fabrication allows for higher performance at lower applied potentials. Thermal measurements were performed on both the presented silicon chips and previously published PDMS devices comprised of microposts. Trapping and separation of 1 and 2 μm polystyrene particles was demonstrated. These results demonstrate the feasibility of high-performance silicon iDEP devices for the next generation of sorting and concentration microsystems. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of an SOI Boot-Strapped Full-Bridge MOSFET Driver, Type CHT-FBDR, under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2009-01-01

Electronic systems designed for use in deep space and planetary exploration missions are expected to encounter extreme temperatures and wide thermal swings. Silicon-based devices are limited in their wide-temperature capability and usually require extra measures, such as cooling or heating mechanisms, to provide adequate ambient temperature for proper operation. Silicon-On-Insulator (SOI) technology, on the other hand, lately has been gaining wide spread use in applications where high temperatures are encountered. Due to their inherent design, SOI-based integrated circuit chips are able to operate at temperatures higher than those of the silicon devices by virtue of reducing leakage currents, eliminating parasitic junctions, and limiting internal heating. In addition, SOI devices provide faster switching, consume less power, and offer improved radiation-tolerance. Very little data, however, exist on the performance of such devices and circuits under cryogenic temperatures. In this work, the performance of an SOI bootstrapped, full-bridge driver integrated circuit was evaluated under extreme temperatures and thermal cycling. The investigations were carried out to establish a baseline on the functionality and to determine suitability of this device for use in space exploration missions under extreme temperature conditions.

Development of an Ultrasonic Airflow Measurement Device for Ducted Air

PubMed Central

Raine, Andrew B.; Aslam, Nauman; Underwood, Christopher P.; Danaher, Sean

2015-01-01

In this study, an in-duct ultrasonic airflow measurement device has been designed, developed and tested. The airflow measurement results for a small range of airflow velocities and temperatures show that the accuracy was better than 3.5% root mean square (RMS) when it was tested within a round or square duct compared to the in-line Venturi tube airflow meter used for reference. This proof of concept device has provided evidence that with further development it could be a low-cost alternative to pressure differential devices such as the orifice plate airflow meter for monitoring energy efficiency performance and reliability of ventilation systems. The design uses a number of techniques and design choices to provide solutions to lower the implementation cost of the device compared to traditional airflow meters. The design choices that were found to work well are the single sided transducer arrangement for a “V” shaped reflective path and the use of square wave transmitter pulses ending with the necessary 180° phase changed pulse train to suppress transducer ringing. The device is also designed so that it does not have to rely on high-speed analogue to digital converters (ADC) and intensive digital signal processing, so could be implemented using voltage comparators and low-cost microcontrollers. PMID:25954952

Measuring arterial oxygenation in a high altitude field environment: comparing portable pulse oximetry with blood gas analysis.

PubMed

Ross, Elliot M; Matteucci, Michael J; Shepherd, Matthew; Barker, Matthew; Orr, Lance

2013-06-01

High altitude environments present unique medical treatment challenges. Medical providers often use small portable pulse oximetry devices to help guide their clinical decision making. A significant body of high altitude research is based on the use of these devices to monitor hypoxia, yet there is a paucity of evidence that these devices are accurate in these environments. We studied whether these devices perform accurately and reliably under true mountain conditions. Healthy unacclimatized active-duty military volunteers participating in mountain warfare training at 2100 m (6900 feet) above sea level were evaluated with several different pulse oximetry devices while in a cold weather, high altitude field environment and then had arterial blood gases (ABG) drawn using an i-STAT for comparison. The pulse oximeter readings were compared with the gold standard ABG readings. A total of 49 individuals completed the study. There was no statistically significant difference between any of the devices and the gold standard of ABG. The best performing device was the PalmSAT (PS) 8000SM finger probe with a mean difference of 2.17% and SD of 2.56 (95% CI, 1.42% to 2.92%). In decreasing order of performance were the PS 8000AA finger probe (mean ± SD, 2.54% ± 2.68%; 95% CI, 1.76% to 3.32%), the PS 8000Q ear probe (2.47% ± 4.36%; 95% CI, 1.21% to 3.75%), the Nonin Onyx 9500 (3.29% ± 3.12%; 95% CI, 2.39% to 4.20%), and finally the PS 8000R forehead reflectance sensor (5.15% ± 2.97%; 95% CI, 4.28% to 6.01%). Based on the results of this study, results of the newer portable pulse oximeters appear to be closely correlated to that of the ABG measurements when tested in true mountain conditions. Copyright © 2013 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Public-use blood pressure measurement: the kiosk quandary.

PubMed

Alpert, Bruce S; Dart, Richard A; Sica, Domenic A

2014-10-01

It is important to note the opportunity that validated public-use kiosks offer the U.S. healthcare system in terms of ease of public access, reduced cost of screening/monitoring, and the opportunity to support coordinated care between physicians, pharmacists, and patients. It is equally important to recognize that all public-use BP kiosks are not equivalent. Members of the AAMI Sphygmomanometer Committee and other ‘‘concerned citizens’’ are working with FDA officials to try to improve both device validation and cuff range performance of these devices. In reality, regulatory changes will be slow to take effect, and for the foreseeable future, the burden of device accuracy assessment lies with the private sector and the public. There is a device currently available that has undergone full validation testing and offers a wide-range cuff validated for almost all US adult arms. We recognize the importance of innovation in out-of-office BP measurement. Therefore, in the interest of public health, we strongly urge those business professionals buying such devices, and those health professionals advising patients on their use, to become better informed and more discriminant in their device selection.

A simple cost-effective manometric respirometer: design and application in wastewater biomonitoring

NASA Astrophysics Data System (ADS)

Rahman, Mohammad Shahidur; Islam, M. Akhtarul

2015-09-01

Application of respirometric tools in wastewater engineering fields is still not getting familiarity and acceptance by academy or industry in developing countries as compared to the use of conventional biochemical oxygen demand (BOD) approach. To justify the applicability of respirometry, a low-cost respirometric device suitable for monitoring biodegradation process in wastewater has been developed. This device contains six independently operating reactors placed in a temperature control unit for the bioassay of five wastewater samples simultaneously (along with one blank). Each reactor is equipped with a magnetic stirrer for the continuous agitation of the test sample. Six manometers, linked with the individual reactors, measure the pressure and volume changes in the headspace gas phase of the reactor. Working formulae have been derived to convert the `volume-change in gas phase' data to `the oxygen depletion in the whole liquid-gas system' data. The performance of the device has been tested with glucose-glutamic acid standard solution and found satisfactory. Conventional BOD test and the respirometric measurements were performed simultaneously and it is found that in addition to measuring the BOD of the sample, this device gives oxygen uptake profile for further analysis to determine the biokinetic coefficients. Additionally, in some cases, following a specific test protocol, the respirometer can indirectly estimate the carbon dioxide evolved during biodegradation process for calculating respiratory activity parameter such as respiratory quotient. It is concluded that the device can be used in the laboratories associated with the activated sludge plants and also for teaching and research purposes in developing countries.

78 FR 24817 - Visual-Manual NHTSA Driver Distraction Guidelines for In-Vehicle Electronic Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-26

...The National Highway Traffic Safety Administration (NHTSA) is concerned about the effects of distraction on motor vehicle safety due to drivers' use of electronic devices. Consequently, NHTSA is issuing nonbinding, voluntary Driver Distraction Guidelines (NHTSA Guidelines) to promote safety by discouraging the introduction of excessively distracting devices in vehicles. This notice announces the issuance of the final version of the first phase of the NHTSA Guidelines. This first phase applies to original equipment (OE) in-vehicle electronic devices used by the driver to perform secondary tasks (communications, entertainment, information gathering, navigation tasks, etc. are considered secondary tasks) through visual-manual means (i.e., the driver looks at a device, manipulates a device-related control with his or her hand, and/or watches for visual feedback). The NHTSA Guidelines list certain secondary tasks believed by the agency to interfere inherently with a driver's ability to safely control the vehicle. The NHTSA Guidelines recommend that in-vehicle devices be designed so that they cannot be used by the driver to perform these inherently distracting secondary tasks while driving. For all other visual-manual secondary tasks, the NHTSA Guidelines specify a test method for measuring eye glance behavior during those tasks. Eye glance metrics are compared to acceptance criteria to evaluate whether a task interferes too much with driver attention, rendering it unsuitable for a driver to perform while driving. If a task does not meet the acceptance criteria, the NHTSA Guidelines recommend that the task be made inaccessible for performance by the driver while driving. In addition, the NHTSA Guidelines contain several recommendations to limit and reduce the potential for distraction associated with the use of OE in-vehicle electronic devices.

The Use of MCNP in Flash Radiographic Applications at AWE

NASA Astrophysics Data System (ADS)

Quillin, S.; Crotch, I.; McAlpin, S.; O'Malley, J.

AWE performs experiments to investigate the hydrodynamic behavior of explosive metal systems in order to underwrite the UK nuclear deterrent. The experiments involve the manufacture of a device to mock up some aspect of the weapon. Inert simulant materials replace fissile weapon components. The device is then detonated under remote control within specially designed explosive containment buildings called firing chambers. During the experiment a very brief, intense, collimated flash of high energy x-rays are used to take a snapshot of the implosion (see Fig. 1). Prom the resulting image measurements of the dynamic configuration and density distribution of the components in the device are inferred. These are then used to compare with calculations of the hydrodynamic operation of the weapon and understand how the device would perform under various conditions. This type of experiment is known as a core punch experiment.

Systems and methods for detection of blowout precursors in combustors

DOEpatents

Lieuwen, Tim C.; Nair, Suraj

2006-08-15

The present invention comprises systems and methods for detecting flame blowout precursors in combustors. The blowout precursor detection system comprises a combustor, a pressure measuring device, and blowout precursor detection unit. A combustion controller may also be used to control combustor parameters. The methods of the present invention comprise receiving pressure data measured by an acoustic pressure measuring device, performing one or a combination of spectral analysis, statistical analysis, and wavelet analysis on received pressure data, and determining the existence of a blowout precursor based on such analyses. The spectral analysis, statistical analysis, and wavelet analysis further comprise their respective sub-methods to determine the existence of blowout precursors.

Development of Skylab medical equipment and flight preparations

NASA Technical Reports Server (NTRS)

Johnston, R. S.; Stonesifer, J. C.; Hawkins, W. R.

1975-01-01

The major medical systems in the Skylab orbital workshop are described. They comprise the food system, the waste management system, operational bioinstrumentation, personal hygiene, gas sampling, an inflight medical support system, and a cardiovascular counterpressure garment. Life sciences experiments carried out aboard Skylab are also reviewed; these include an ergometer and metabolic analyzer, a lower-body negative pressure device, an electrode harness and body temperature probe, a blood pressure cuff, a leg volume measuring band, sleep studies, a body-mass measuring device, a rotating litter chair, a blood sample processor, and small-mass measuring apparatus. All performance requirements were met with the equipment, and no failures were encountered.

The better way to determine the validity, reliability, objectivity and accuracy of measuring devices.

PubMed

Pazira, Parvin; Rostami Haji-Abadi, Mahdi; Zolaktaf, Vahid; Sabahi, Mohammadfarzan; Pazira, Toomaj

2016-06-08

In relation to statistical analysis, studies to determine the validity, reliability, objectivity and precision of new measuring devices are usually incomplete, due in part to using only correlation coefficient and ignoring the data dispersion. The aim of this study was to demonstrate the best way to determine the validity, reliability, objectivity and accuracy of an electro-inclinometer or other measuring devices. Another purpose of this study is to answer the question of whether reliability and objectivity represent accuracy of measuring devices. The validity of an electro-inclinometer was examined by mechanical and geometric methods. The objectivity and reliability of the device was assessed by calculating Cronbach's alpha for repeated measurements by three raters and by measurements on the same person by mechanical goniometer and the electro-inclinometer. Measurements were performed on "hip flexion with the extended knee" and "shoulder abduction with the extended elbow." The raters measured every angle three times within an interval of two hours. The three-way ANOVA was used to determine accuracy. The results of mechanical and geometric analysis showed that validity of the electro-inclinometer was 1.00 and level of error was less than one degree. Objectivity and reliability of electro-inclinometer was 0.999, while objectivity of mechanical goniometer was in the range of 0.802 to 0.966 and the reliability was 0.760 to 0.961. For hip flexion, the difference between raters in joints angle measurement by electro-inclinometer and mechanical goniometer was 1.74 and 16.33 degree (P<0.05), respectively. The differences for shoulder abduction measurement by electro-inclinometer and goniometer were 0.35 and 4.40 degree (P<0.05). Although both the objectivity and reliability are acceptable, the results showed that measurement error was very high in the mechanical goniometer. Therefore, it can be concluded that objectivity and reliability alone cannot determine the accuracy of a device and it is preferable to use other statistical methods to compare and evaluate the accuracy of these two devices.

LEO Flight Testing of GaAs on Si Solar Cells Aboard MISSES

NASA Technical Reports Server (NTRS)

Wilt, David M.; Clark, Eric B.; Ringel, Steven A.; Andre, Carrie L.; Smith, Mark A.; Scheiman, David A.; Jenkins, Phillip P.; Maurer, William F.; Fitzgerald, Eugene A.; Walters, R. J.

2004-01-01

Previous research efforts have demonstrated small area (0.04 cm) GaAs on Si (GaAs/Si) solar cells with AM0 efficiencies in excess of 17%. These results were achieved on Si substrates coated with a step graded buffer of Si(x),Ge(1-x) alloys graded to 100% Ge. Recently, a 100-fold increase in device area was accomplished for these devices in preparation for on-orbit testing of this technology aboard Materials International Space Station Experiment number 5 (MISSE5). The GaAs/Si MISSE5 experiment contains five (5) GaAs/Si test devices with areas of lcm(exp 2) and 4cm(exp 4) as well as two (2) GaAs on GaAs control devices. Electrical performance data, measured on-orbit for three (3) of the test devices and one (1) of the control devices, will be telemetered to ground stations daily. After approximately one year on orbit, the MISSE5 payload will be returned to Earth for post flight evaluation. This paper will discuss the development of the GaAs/Si devices for the MISSE5 flight experiment and will present recent ground and on-orbit performance data.

Analytical performance of glucose monitoring systems at different blood glucose ranges and analysis of outliers in a clinical setting.

PubMed

Hasslacher, Christoph; Kulozik, Felix; Platten, Isabel

2014-05-01

We investigated the analytical accuracy of 27 glucose monitoring systems (GMS) in a clinical setting, using the new ISO accuracy limits. In addition to measuring accuracy at blood glucose (BG) levels < 100 mg/dl and > 100 mg/dl, we also analyzed devices performance with respect to these criteria at 5 specific BG level ranges, making it possible to further differentiate between devices with regard to overall performance. Carbohydrate meals and insulin injections were used to induce an increase or decrease in BG levels in 37 insulin-dependent patients. Capillary blood samples were collected at 10-minute intervals, and BG levels determined simultaneously using GMS and a laboratory-based method. Results obtained via both methods were analyzed according to the new ISO criteria. Only 12 of 27 devices tested met overall requirements of the new ISO accuracy limits. When accuracy was assessed at BG levels < 100 mg/dl and > 100 mg/dl, criteria were met by 14 and 13 devices, respectively. A more detailed analysis involving 5 different BG level ranges revealed that 13 (48.1%) devices met the required criteria at BG levels between 50 and 150 mg/dl, whereas 19 (70.3%) met these criteria at BG levels above 250 mg/dl. The overall frequency of outliers was low. The assessment of analytical accuracy of GMS at a number of BG level ranges made it possible to further differentiate between devices with regard to overall performance, a process that is of particular importance given the user-centered nature of the devices' intended use. © 2014 Diabetes Technology Society.

Determining the risks of clinically indicated nonthoracic magnetic resonance imaging at 1.5 T for patients with pacemakers and implantable cardioverter-defibrillators: rationale and design of the MagnaSafe Registry.

PubMed

Russo, Robert J

2013-03-01

Until recently, the presence of a permanent pacemaker or an implantable cardioverter-defibrillator has been a relative contraindication for the performance of magnetic resonance imaging (MRI). A number of small studies have shown that MRI can be performed with minimal risk when patients are properly monitored and device programming is modified appropriately for the procedure. However, the risk of performing MRI for patients with implanted cardiac devices has not been sufficiently evaluated to advocate routine clinical use. The aim of the present protocol is to prospectively determine the rate of adverse clinical events and device parameter changes in patients with implanted non-MRI-conditional cardiac devices undergoing clinically indicated nonthoracic MRI at 1.5 T. The MagnaSafe Registry is a multicenter, prospective cohort study of up to 1500 MRI examinations in patients with pacemakers or implantable cardioverter-defibrillators implanted after 2001 who undergo clinically indicated nonthoracic MRI following a specific protocol to ensure that preventable potential adverse events are mitigated. Adverse events and changes in device parameter measurements that may be associated with the imaging procedure will be documented. Through August 2012, 701 MRI studies have been performed, representing 47% of the total target enrollment. The results of this registry will provide additional documentation of the risk of MRI and will further validate a clinical protocol for screening and the performance of clinically indicated MRI for patients with implanted cardiac devices. Copyright © 2013 Mosby, Inc. All rights reserved.

Development and evaluation of a soft wearable weight support device for reducing muscle fatigue on shoulder

PubMed Central

Cho, Kyu-Jin

2017-01-01

Compensating the weight of human limbs is important in reducing muscle fatigue experienced by manual laborers. In this study, a compact and lightweight soft wearable weight support device was developed and evaluated. The device supports gravitational force on the shoulder at any arm posture, although there are some limitations in its assistive performance. The device actuator consists of a cam-rod structure, a tendon-driven mechanism, and a rubber band. The desired assistive torque is translated to the shoulder joint along a tendon routing structure. Device performance was evaluated by measuring muscle activation in with-assist and without-assist conditions. Muscle activation on the deltoid was measured by surface electromyography. An experimental protocol consisting of a series of exercises was executed with six healthy subjects. The subjects raised and lowered their arm from 0 to 100 degrees for 30 times under eight conditions, which were combined with-assist and without-assist conditions, and holding the horizontal angle of the arm at 0, 30, 60, or 90 degrees against the sagittal plane. Surface electromyography data were pre-processed and analyzed using a root mean square method. When muscle fatigue occurs, the root mean square of the surface electromyography increases nonlinearly. This was calculated using the standard deviation of the root mean square. Three of six subjects showed decreased variation of the root mean square between the exercises in the with-assist condition. One subject’s result was significantly reduced (by about 57.6%) in the with-assist condition. In contrast, two subjects did not show significant difference between measurements taken in the with-assist and without-assist conditions. One subject was dropped from the experiment because the device did not fit the subject’s body. In conclusion, the effectiveness of the soft wearable weight support device in supporting shoulder movements was verified through the decreased variation of muscle activation. PMID:28291825

Development and evaluation of a soft wearable weight support device for reducing muscle fatigue on shoulder.

PubMed

Park, Daegeun; Cho, Kyu-Jin

2017-01-01

Compensating the weight of human limbs is important in reducing muscle fatigue experienced by manual laborers. In this study, a compact and lightweight soft wearable weight support device was developed and evaluated. The device supports gravitational force on the shoulder at any arm posture, although there are some limitations in its assistive performance. The device actuator consists of a cam-rod structure, a tendon-driven mechanism, and a rubber band. The desired assistive torque is translated to the shoulder joint along a tendon routing structure. Device performance was evaluated by measuring muscle activation in with-assist and without-assist conditions. Muscle activation on the deltoid was measured by surface electromyography. An experimental protocol consisting of a series of exercises was executed with six healthy subjects. The subjects raised and lowered their arm from 0 to 100 degrees for 30 times under eight conditions, which were combined with-assist and without-assist conditions, and holding the horizontal angle of the arm at 0, 30, 60, or 90 degrees against the sagittal plane. Surface electromyography data were pre-processed and analyzed using a root mean square method. When muscle fatigue occurs, the root mean square of the surface electromyography increases nonlinearly. This was calculated using the standard deviation of the root mean square. Three of six subjects showed decreased variation of the root mean square between the exercises in the with-assist condition. One subject's result was significantly reduced (by about 57.6%) in the with-assist condition. In contrast, two subjects did not show significant difference between measurements taken in the with-assist and without-assist conditions. One subject was dropped from the experiment because the device did not fit the subject's body. In conclusion, the effectiveness of the soft wearable weight support device in supporting shoulder movements was verified through the decreased variation of muscle activation.

Electronic voltage and current transformers testing device.

PubMed

Pan, Feng; Chen, Ruimin; Xiao, Yong; Sun, Weiming

2012-01-01

A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs) with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation signal is fed to their primaries. The test that estimates the performance of the prototype has been carried out at the National Centre for High Voltage Measurement and the prototype is approved for testing transformers with precision class up to 0.2 at the industrial frequency (50 Hz or 60 Hz). The device is suitable for on-site testing due to its high accuracy, simple structure and low-cost hardware.

An induction heater device for studies of magnetic hyperthermia and specific absorption ratio measurements

NASA Astrophysics Data System (ADS)

Cano, M. E.; Barrera, A.; Estrada, J. C.; Hernandez, A.; Cordova, T.

2011-11-01

The development of a device for generating ac magnetic fields based on a resonant inverter is presented, which has been specially designed to carry out experiments of magnetic hyperthermia. By determining the electric current in the LC resonant circuit, a maximum intensity of magnetic field around of 15 mT is calculated, with a frequency around of 206 kHz. This ac magnetic field is able to heat powdered magnetic materials embedded in biological systems to be used in biomedical applications. Indeed, in order to evaluate the sensitivity of the device we also present the measurements of the specific absorption rate in phantoms performed with commercially prepared Fe3O4 and distilled water at different concentrations.

Validation of the Beneware model ABP-021 ambulatory blood pressure monitor according to the revised 2010 European Society of hypertension international protocol.

PubMed

Pereira, Telmo; Guimarães, João

2018-06-11

This study aimed to evaluate the accuracy of the Beneware model ABP-021 oscillometric blood pressure monitor in the general population according to the European Society of Hypertension International Protocol (ESH-IP). The accuracy of the device was assessed in relation to various clinical variables, including age, sex, BMI, and arm circumference. Thirty-three individuals (18 men and 15 women), with a mean age of 36±14 years (age range: 20-68 years), were studied according to the recommendations of the ESH-IP. Sequential same-arm blood pressure measurements were performed, alternating between a mercury standard and the automatic device. The differences among the test-control measurements were assessed and divided into categorization zones of 5, 10, and 15 mmHg discrepancy. The device complied with the quality requirements of the ESH-IP. The device-observer disagreement was -1.2±4.7 mmHg for systolic blood pressure (SBP) and -1.7±4.3 mmHg for diastolic blood pressure (DBP). The device produced 77, 93, and 98 measurements, respectively, within the 5, 10, and 15 mmHg discrepancy limits for SBP. For DBP, 80, 97, and 99 measurements were observed within the 5, 10, and 15 mmHg discrepancy limits. The number of participants with two or three of the device-observer differences within 5 mmHg was 26 for SBP and 29 for DBP, whereas there were only two participants with no device-observer differences within 5 mmHg for DBP. These data show that the Beneware model ABP-021 monitor meets the requirements of the ESH-IP, in static conditions, indicating its suitability for measuring blood pressure in the general adult population.

Correlation Between Bone Density and Instantaneous Torque at Implant Site Preparation: A Validation on Polyurethane Foam Blocks of a Device Assessing Density of Jawbones.

PubMed

Di Stefano, Danilo Alessio; Arosio, Paolo

2016-01-01

Bone density at implant placement sites is one of the key factors affecting implant primary stability, which is a determinant for implant osseointegration and rehabilitation success. Site-specific bone density assessment is, therefore, of paramount importance. Recently, an implant micromotor endowed with an instantaneous torque-measuring system has been introduced. The aim of this study was to assess the reliability of this system. Five blocks with different densities (0.16, 0.26, 0.33, 0.49, and 0.65 g/cm(3)) were used. A single trained operator measured the density of one of them (0.33 g/cm(3)), by means of five different devices (20 measurements/device). The five resulting datasets were analyzed through the analysis of variance (ANOVA) model to investigate interdevice variability. As differences were not significant (P = .41), the five devices were each assigned to a different operator, who collected 20 density measurements for each block, both under irrigation (I) and without irrigation (NI). Measurements were pooled and averaged for each block, and their correlation with the actual block-density values was investigated using linear regression analysis. The possible effect of irrigation on density measurement was additionally assessed. Different devices provided reproducible, homogenous results. No significant interoperator variability was observed. Within the physiologic range of densities (> 0.30 g/cm(3)), the linear regression analysis showed a significant linear correlation between the mean torque measurements and the actual bone densities under both drilling conditions (r = 0.990 [I], r = 0.999 [NI]). Calibration lines were drawn under both conditions. Values collected under irrigation were lower than those collected without irrigation at all densities. The NI/I mean torque ratio was shown to decrease linearly with density (r = 0.998). The mean error introduced by the device-operator system was less than 10% in the range of normal jawbone density. Measurements performed with the device were linearly correlated with the blocks' bone densities. The results validate the device as an objective intraoperative tool for bone-density assessment that may contribute to proper jawbone-density evaluation and implant-insertion planning.

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

DOE PAGES

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

2017-01-30

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

Controlling metastable native point-defect populations in Cu(In,Ga)Se2 and Cu2ZnSnSe4 materials and solar cells through voltage-bias annealing

NASA Astrophysics Data System (ADS)

Teeter, G.; Harvey, S. P.; Johnston, S.

2017-01-01

This contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu2ZnSnSe4 (CZTSe), Cu(In,Ga)Se2 (CIGS), and CdS material properties and solar cell performance. To quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 °C to 215 °C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200 °C for CIGS and 110 °C-215 °C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

Smart instrumentation for determination of ligament stiffness and ligament balance in total knee arthroplasty.

PubMed

Hasenkamp, W; Villard, J; Delaloye, J R; Arami, A; Bertsch, A; Jolles, B M; Aminian, K; Renaud, P

2014-06-01

Ligament balance is an important and subjective task performed during total knee arthroplasty (TKA) procedure. For this reason, it is desirable to develop instruments to quantitatively assess the soft-tissue balance since excessive imbalance can accelerate prosthesis wear and lead to early surgical revision. The instrumented distractor proposed in this study can assist surgeons on performing ligament balance by measuring the distraction gap and applied load. Also the device allows the determination of the ligament stiffness which can contribute a better understanding of the intrinsic mechanical behavior of the knee joint. Instrumentation of the device involved the use of hall-sensors for measuring the distractor displacement and strain gauges to transduce the force. The sensors were calibrated and tested to demonstrate their suitability for surgical use. Results show the distraction gap can be measured reliably with 0.1mm accuracy and the distractive loads could be assessed with an accuracy in the range of 4N. These characteristics are consistent with those have been proposed, in this work, for a device that could assist on performing ligament balance while permitting surgeons evaluation based on his experience. Preliminary results from in vitro tests were in accordance with expected stiffness values for medial collateral ligament (MCL) and lateral collateral ligament (LCL). Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers

PubMed Central

Parry, Dave; Cooper, Chris E.

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis. uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming. PMID:29692951

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers.

PubMed

Jones, Ben; Parry, Dave; Cooper, Chris E

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis . uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming.

Noguchi uses BMMD in SM

NASA Image and Video Library

2010-05-26

ISS023-E-052104 (26 May 2010) --- Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, Expedition 23 flight engineer, uses the IM mass measurement device to perform the PZEh-MO-8/Body Mass Measurement Russian biomedical routine assessments in the Zvezda Service Module of the International Space Station.

Pulse Transit Time Measurement Using Seismocardiogram, Photoplethysmogram, and Acoustic Recordings: Evaluation and Comparison.

PubMed

Yang, Chenxi; Tavassolian, Negar

2018-05-01

This work proposes a novel method of pulse transit time (PTT) measurement. The proximal arterial location data are collected from seismocardiogram (SCG) recordings by placing a micro-electromechanical accelerometer on the chest wall. The distal arterial location data are recorded using an acoustic sensor placed inside the ear. The performance of distal location recordings is evaluated by comparing SCG-acoustic and SCG-photoplethysmogram (PPG) measurements. PPG and acoustic performances under motion noise are also compared. Experimental results suggest comparable performances for the acoustic-based and PPG-based devices. The feasibility of each PTT measurement method is validated for blood pressure evaluations and its limitations are analyzed.

Performance of 4x5120 Element Visible and 2x2560 Element Shortwave Infrared Multispectral Focal Planes

NASA Astrophysics Data System (ADS)

Tower, J. R.; Cope, A. D.; Pellion, L. E.; McCarthy, B. M.; Strong, R. T.; Kinnard, K. F.; Moldovan, A. G.; Levine, P. A.; Elabd, H.; Hoffman, D. M.

1985-12-01

Performance measurements of two Multispectral Linear Array focal planes are presented. Both pushbroom sensors have been developed for application in remote sensing instruments. A buttable, four-spectral-band, linear-format charge coupled device (CCD) and a but-table, two-spectral-band, linear-format, shortwave infrared charge coupled device (IRCCD) have been developed under NASA funding. These silicon integrated circuits may be butted end to end to provide very-high-resolution multispectral focal planes. The visible CCD is organized as four sensor lines of 1024 pixels each. Each line views the scene in a different spectral window defined by integral optical bandpass filters. A prototype focal plane with five devices, providing 4x5120-pixel resolution has been demonstrated. The high quantum efficiency of the backside-illuminated CCD technology provides excellent signal-to-noise performance and unusually high MTF across the entire visible and near-IR spectrum. The shortwave infrared (SWIR) sensor is organized as two line sensors of 512 detectors each. The SWIR (1-2.5 μm) spectral windows may be defined by bandpass filters placed in close proximity to the devices. The dual-band sensor consists of Schottky barrier detectors read out by CCD multiplexers. This monolithic sensor operates at 125°K with radiometric performance. A prototype five-device focal plane providing 2x2560 detectors has been demonstrated. The devices provide very high uniformity, and excellent MTF across the SWIR band.

Performance evaluation of radiation sensors with internal signal amplification based on the BJT effect

NASA Astrophysics Data System (ADS)

Bosisio, Luciano; Batignani, Giovanni; Bettarini, Stefano; Boscardin, Maurizio; Dalla Betta, Gian-Franco; Giacomini, Gabriele; Piemonte, Claudio; Verzellesi, Giovanni; Zorzi, Nicola

2006-11-01

Prototypes of ionizing radiation detectors with internal signal amplification based on the bipolar transistor effect have been fabricated at ITC-irst (Trento, Italy). Results from the electrical characterization and preliminary functional tests of the devices have been previously reported. Here, we present a more detailed investigation of the performance of this type of detector, with particular attention to their noise and rate limits. Measurements of the signal waveform and of the gain versus frequency dependence are performed by illuminating the devices with, respectively, pulsed or sinusoidally modulated IR light. Pulse height spectra of X-rays from an Am241 source have been taken with very simple front-end electronics (an LF351 operational amplifier) or by directly reading with an oscilloscope the voltage drop across a load resistor connected to the emitter. An equivalent noise charge (referred to input) of 380 electrons r.m.s. has been obtained with the first setup for a small device, with an active area of 0.5×0.5 mm2 and a depleted thickness of 0.6 mm. The corresponding power dissipation in the BJT was 17 μW. The performance limitations of the devices are discussed.

Collection-limited theory interprets the extraordinary response of single semiconductor organic solar cells

DOE PAGES

Ray, Biswajit; Baradwaj, Aditya G.; Khan, Mohammad Ryyan; ...

2015-08-19

The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. In this paper, we show that the short-circuit current density from SS-OPVmore » devices can be enhanced significantly (~100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: ( i) detailed numerical simulations, ( ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and ( iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. Finally, these insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials.« less

MR Guided Pulsed High Intensity Focused Ultrasound Enhancement of Gene Therapy Combined with Androgen Deprivation and Radiotherapy for Prostate Cancer Treatment

DTIC Science & Technology

2012-09-01

for the treatment of prostate tumor-bearing mice using a clinical MRgHIFU device. We performed animal studies for quantitative measurement of the...by measuring the protein expression level of MDM2, p53 and p21 using immunohistochemical staining and west blotting techniques. We also performed...therapy) in implanted prostate tumors in mice in vivo by measuring the protein expression level of MDM, p53 and p21 with time points after treatment

Hypothermia Severely Effects Performance of Nitinol-Based Endovascular Grafts In Vitro

PubMed Central

Robich, Michael P.; Hagberg, Robert; Schermerhorn, Marc L.; Pomposelli, Frank B.; Nilson, Michael C.; Gendron, Michelle L.; Sellke, Frank W.; Rodriguez, Roberto

2012-01-01

Background Nitinol is an alloy that serves as the base for numerous medical devices, including the GORE TAG Thoracic Endoprosthesis (W.L. Gore & Associates, Flagstaff, AZ) thoracic aortic graft device. Given the increasing use of therapeutic hypothermia used during the placement these devices and in post– cardiac arrest situations, we sought to understand the impact of hypothermia on this device. Methods Five 34-mm TAG devices were deployed in a temperature-controlled chamber at 20°C, 25°C, 30°C, 35°, and 37°C (25 total devices). A halographic measurement device was used to measure radial expansive force and normalized to the force at 37°C. Three 34-mm TAG devices were similarly deployed in a temperature-controlled water bath at each of the above temperatures. A laser micrometer was utilized to measure deployed diameter. Results A statistically significant decrease in expansive force at 20°C, 25°C, and 30°C of 65%, 46%, and 6%, respectively, was noted. A statistically significant decrease in radial diameter at 20°C and 25°C of 17% and 11%, respectively, was noted. Although a 9% difference was noted at 30°C, it was not significant. Conclusions The nitinol-based TAG device shows marked decreases in radial expansive force and deployed diameter at temperatures at or below 30°C. Surgeons should be aware of the potential implications of placing nitinol-based endoprostheses in hypothermic conditions. In addition, all health care providers should be aware of the changes that occur in nitinol-based endoprostheses during therapeutic hypothermia. PMID:22385821

RF upset susceptibilities of CMOS and low power Schottky D-type flip-flops

NASA Astrophysics Data System (ADS)

Kenneally, Daniel J.; Koellen, Daniel S.; Epshtein, Stan

A description is given of measurements of RF upset levels on two D-type flip-flops, the CD4013B and 54ALS74A, which are functionally identical but fabricated from different technologies: CMOS and low-power Schottky. Continuous-wave electromagnetic interference (CW EMI) from 1 MHz to 200 MHz was coupled into the clock, data, and collector bias, Vcc, ports of each device type while test vectors were used to verify normal operation and subsequent upsets. Both the CMOS and the Schottky devices show decreasing RF susceptibility with increasing frequencies from 1 to 200 MHz. The CMOS device roll-off is almost 18 dB/decade as compared to about 12 dB/decade for the Schottky device. The differences in the Vcc ports' susceptibilities are also apparent. The CMOS device's upset levels decrease steeply with increasing frequency at approximate roll-offs of 60 dB/decade up to 5 MHz and 15 dB/decade from 5 to 100 MHz. Over the same bands, the Schottky device susceptibility at the Vcc port remains strikingly constant at a 6-dBm upset level. Measurements on the clock and data ports seem to suggest that: (1) the CMOS device is `RF harder' than the Schottky device by 3 to 18 dB at least above the 5 to 10 MHz range and out to 100 MHz; and (2) below that range, the Schottky device may be `RF harder' by 3 to 6 dB, but there are not enough measurement data to confirm this performance below 5 MHz.

Le Fort I distraction using internal devices for maxillary hypoplasia in patients with cleft lip, palate, and alveolus: complications and their prevention and management.

PubMed

Mitsukawa, Nobuyuki; Satoh, Kaneshige; Morishita, Tadashi

2010-09-01

In recent years, advancement has been made in distraction osteogenesis in the facial area. It has been applied actively to treat maxillary hypoplasia in patients with cleft lip, palate, and alveolus. Le Fort I distraction using internal devices does not lead to disability in daily living, including during the retention period, and has low surgical invasiveness, facile management, and superior aesthetics. Thus, there have been occasional reports on this procedure in recent years. Because an internal device is unidirectional, the greatest disadvantage is the inability to adjust the direction of distraction after its placement. However, past reports have emphasized its advantages, and its complications have rarely been discussed. We performed Le Fort I distraction using internal devices on 15 young patients. Our results showed notable complications in a few cases. When serial cephalometric analysis was performed after maxillary distraction, it demonstrated that the maxilla assumes various three-dimensional distraction morphologies. In particular, cases with insufficient bone grafting of alveolar clefts developed collapse mainly in the alveolar cleft region during postoperative distraction. Mobility and deviation of the maxillary bone fragment occurred. We implemented preventative measures against complications such as using modifications to place the devices parallel on the left and right sides and using a bite splint for distraction. These measures produced improved outcomes, and we describe here the details.

Towards Device-Independent Information Processing on General Quantum Networks

NASA Astrophysics Data System (ADS)

Lee, Ciarán M.; Hoban, Matty J.

2018-01-01

The violation of certain Bell inequalities allows for device-independent information processing secure against nonsignaling eavesdroppers. However, this only holds for the Bell network, in which two or more agents perform local measurements on a single shared source of entanglement. To overcome the practical constraints that entangled systems can only be transmitted over relatively short distances, large-scale multisource networks have been employed. Do there exist analogs of Bell inequalities for such networks, whose violation is a resource for device independence? In this Letter, the violation of recently derived polynomial Bell inequalities will be shown to allow for device independence on multisource networks, secure against nonsignaling eavesdroppers.

Towards Device-Independent Information Processing on General Quantum Networks.

PubMed

Lee, Ciarán M; Hoban, Matty J

2018-01-12

The violation of certain Bell inequalities allows for device-independent information processing secure against nonsignaling eavesdroppers. However, this only holds for the Bell network, in which two or more agents perform local measurements on a single shared source of entanglement. To overcome the practical constraints that entangled systems can only be transmitted over relatively short distances, large-scale multisource networks have been employed. Do there exist analogs of Bell inequalities for such networks, whose violation is a resource for device independence? In this Letter, the violation of recently derived polynomial Bell inequalities will be shown to allow for device independence on multisource networks, secure against nonsignaling eavesdroppers.

InAs/Ga(In)Sb type-II superlattices short/middle dual color infrared detectors

NASA Astrophysics Data System (ADS)

Shi, Yanli; Hu, Rui; Deng, Gongrong; He, Wenjing; Feng, Jiangmin; Fang, Mingguo; Li, Xue; Deng, Jun

2015-06-01

Short wavelength and middle wavelength dual color infrared detector were designed and prepared with InAs/Ga(In)Sb type-II superlattices materials. The Crosslight software was used to calculate the relation between wavelength and material parameter such as thickness of InAs, GaSb, then energy strucutre of 100 periods 8ML/8ML InAs/GaSb and the absorption wavelength was calculated. After fixing InAs/GaSb thickness parameter, devices with nBn and pin structure were designed and prepared to compare performance of these two structures. Comparison results showed both structure devices were available for high temperature operation which black detectivity under 200K were 7.9×108cmHz1/2/W for nBn and 1.9×109cmHz1/2/W for pin respectively. Considering the simultaneous readout requirement for further FPAs application the NIP/PIN InAs/GaSb dual-color structure was grown by MBE method. Both two mesas and one mesa devices structure were designed and prepared to appreciate the short/middle dual color devices. Cl2-based ICP etching combined with phosphoric acid based chemicals were utilized to form mesas, silicon dioxide was deposited via PECVD as passivation layer. Ti/Au was used as metallization. Once the devices were finished, the electro-optical performance was measured. Measurement results showed that optical spectrum response with peak wavelength of 2.7μm and 4.3μm under 77K temperature was gained, the test results agree well with calculated results. Peak detectivity was measured as 2.08×1011cmHz1/2/W and 6.2×1010cmHz1/2/W for short and middle wavelength infrared detector respectively. Study results disclosed that InAs/Ga(In)Sb type-II SLs is available for both short and middle wavelength infrared detecting with good performance by simply altering the thickness of InAs layer and GaSb layer.

Depth-resolved measurement of ocular fundus pulsations by low-coherence tissue interferometry

NASA Astrophysics Data System (ADS)

Dragostinoff, Nikolaus; Werkmeister, René M.; Gröschl, Martin; Schmetterer, Leopold

2009-09-01

A device that allows for the measurement of ocular fundus pulsations at preselected axial positions of a subject's eye is presented. Unlike previously presented systems, which only allow for observation of the strongest reflecting retinal layer, our system enables the measurement of fundus pulsations at a preselected ocular layer. For this purpose the sample is illuminated by light of low temporal coherence. The layer is then selected by positioning one mirror of a Michelson interferometer according to the depth of the layer. The device contains a length measurement system based on partial coherence interferometry and a line scan charge-coupled device camera for recording and online inspection of the fringe system. In-vivo measurements in healthy humans are performed as proof of principle. The algorithms used for enhancing the recorded images are briefly introduced. The contrast of the observed interference pattern is evaluated for different positions of the measurement mirror and at various distances from the front surface of the cornea. The applications of such a system may be wide, including assessment of eye elongation during myopia development and blood-flow-related changes in intraocular volume.

Virtual reality sickness questionnaire (VRSQ): Motion sickness measurement index in a virtual reality environment.

PubMed

Kim, Hyun K; Park, Jaehyun; Choi, Yeongcheol; Choe, Mungyeong

2018-05-01

This study aims to develop a motion sickness measurement index in a virtual reality (VR) environment. The VR market is in an early stage of market formation and technological development, and thus, research on the side effects of VR devices such as simulator motion sickness is lacking. In this study, we used the simulator sickness questionnaire (SSQ), which has been traditionally used for simulator motion sickness measurement. To measure the motion sickness in a VR environment, 24 users performed target selection tasks using a VR device. The SSQ was administered immediately after each task, and the order of work was determined using the Latin square design. The existing SSQ was revised to develop a VR sickness questionnaire, which is used as the measurement index in a VR environment. In addition, the target selection method and button size were found to be significant factors that affect motion sickness in a VR environment. The results of this study are expected to be used for measuring and designing simulator sickness using VR devices in future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validation of the Konsung QD217A for clinical use and self-measurement according to the European Society of Hypertension International Protocol.

PubMed

Wu, Ning; Zhang, Xuezhong; Wang, Wen; Zhang, Hongye

2015-08-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure (BP) monitor Konsung QD217A for home BP monitoring according to the European Society of Hypertension International Protocol revision 2010. Three trained observers validated the performance of these devices by comparing the measurements obtained from these devices with those taken using a standard mercury sphygmomanometer. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were sequentially measured in 33 participants using a standard mercury sphygmomanometer and the Konsung QD217A device. A total of 99 pairs of comparisons were obtained from 33 participants. The QD217A device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and the observers within a range of 5, 10 and 15 mmHg was 70/99, 92/99 and 96/99, respectively, for SBP and 80/99, 94/99 and 99/99, respectively, for DBP. The device also achieved the targets in part 2 of the validation study. A total of 27 and 31 participants for SBP and DBP, respectively, showed at least two of the three device-observers differences within 5 mmHg (required≥24). The number of participants without device-observer difference within 5 mmHg was one for SBP and one for DBP (required≤3). The Konsung upper arm BP monitor QD217A has passed the International Protocol requirements and it can be recommended for clinical use and self-measurement in adults. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Assistive devices alter gait patterns in Parkinson disease: advantages of the four-wheeled walker.

PubMed

Kegelmeyer, Deb A; Parthasarathy, Sowmya; Kostyk, Sandra K; White, Susan E; Kloos, Anne D

2013-05-01

Gait abnormalities are a hallmark of Parkinson's disease (PD) and contribute to fall risk. Therapy and exercise are often encouraged to increase mobility and decrease falls. As disease symptoms progress, assistive devices are often prescribed. There are no guidelines for choosing appropriate ambulatory devices. This unique study systematically examined the impact of a broad range of assistive devices on gait measures during walking in both a straight path and around obstacles in individuals with PD. Quantitative gait measures, including velocity, stride length, percent swing and double support time, and coefficients of variation were assessed in 27 individuals with PD with or without one of six different devices including canes, standard and wheeled walkers (two, four or U-Step). Data were collected using the GAITRite and on a figure-of-eight course. All devices, with the exception of four-wheeled and U-Step walkers significantly decreased gait velocity. The four-wheeled walker resulted in less variability in gait measures and had less impact on spontaneous unassisted gait patterns. The U-Step walker exhibited the highest variability across all parameters followed by the two-wheeled and standard walkers. Higher variability has been correlated with increased falls. Though subjects performed better on a figure-of-eight course using either the four-wheeled or the U-Step walker, the four-wheeled walker resulted in the most consistent improvement in overall gait variables. Laser light use on a U-Step walker did not improve gait measures or safety in figure-of-eight compared to other devices. Of the devices tested, the four-wheeled-walker offered the most consistent advantages for improving mobility and safety. Copyright © 2012 Elsevier B.V. All rights reserved.

Anisotropic Laminar Piezocomposite Actuator Incorporating Machined PMN-PT Single Crystal Fibers

NASA Technical Reports Server (NTRS)

Wilkie, W. Keats; Inman, Daniel J.; Lloyd, Justin M.; High, James W.

2006-01-01

The design, fabrication, and testing of a flexible, laminar, anisotropic piezoelectric composite actuator utilizing machined PMN-32%PT single crystal fibers is presented. The device consists of a layer of rectangular single crystal piezoelectric fibers in an epoxy matrix, packaged between interdigitated electrode polyimide films. Quasistatic free-strain measurements of the single crystal device are compared with measurements from geometrically identical specimens incorporating polycrystalline PZT-5A and PZT-5H piezoceramic fibers. Free-strain actuation of the single crystal actuator at low bipolar electric fields (+/- 250 V/mm) is approximately 400% greater than that of the baseline PZT-5A piezoceramic device, and 200% greater than that of the PZT-5H device. Free-strain actuation under high unipolar electric fields (0-4kV/mm) is approximately 200% of the PZT-5A baseline device, and 150% of the PZT-5H alternate piezoceramic device. Performance increases at low field are qualitatively consistent with predicted increases based on scaling the low-field d33 piezoelectric constants of the respective piezoelectric materials. High-field increases are much less than scaled d33 estimates, but appear consistent with high-field freestrain measurements reported for similar bulk single-crystal and piezoceramic compositions. Measurements of single crystal actuator capacitance and coupling coefficient are also provided. These properties were poorly predicted using scaled bulk material dielectric and coupling coefficient data. Rules-of-mixtures calculations of the effective elastic properties of the single crystal device and estimated actuation work energy densities are also presented. Results indicate longitudinal stiffnesses significantly lower (50% less) than either piezoceramic device. This suggests that single-crystal piezocomposite actuators will be best suited to low induced-stress, high strain and deflection applications.

Anisotropic Piezocomposite Actuator Incorporating Machined PMN-PT Single Crystal Fibers

NASA Technical Reports Server (NTRS)

Wilkie, W. Keats; Inman, Daniel J.; Lloyd, Justin M.; High, James W.

2004-01-01

The design, fabrication, and testing of a flexible, planar, anisotropic piezoelectric composite actuator utilizing machined PMN-32%PT single crystal fibers is presented. The device consists of a layer of rectangular single crystal piezoelectric fibers in an epoxy matrix, packaged between interdigitated electrode polyimide films. Quasistatic free-strain measurements of the single crystal device are compared with measurements from geometrically identical specimens incorporating polycrystalline PZT-5A and PZT-5H piezoceramic fibers. Free-strain actuation of the single crystal actuator at low bipolar electric fields (+/- 250 V/mm) is approximately 400% greater than that of the baseline PZT-5A piezoceramic device, and 200% greater than that of the PZT-5H device. Free-strain actuation under high unipolar electric fields (0-4kV/mm) is approximately 200% of the PZT-5A baseline device, and 150% of the PZT-5H alternate piezoceramic device. Performance increases at low field are qualitatively consistent with predicted increases based on scaling the low-field d(sub 33) piezoelectric constants of the respective piezoelectric materials. High-field increases are much less than scaled d(sub 33) estimates, but appear consistent with high-field freestrain measurements reported for similar bulk single-crystal and piezoceramic compositions. Measurements of single crystal actuator capacitance and coupling coefficient are also provided. These properties were poorly predicted using scaled bulk material dielectric and coupling coefficient data. Rules-of-mixtures calculations of the effective elastic properties of the single crystal device and estimated actuation work energy densities are also presented. Results indicate longitudinal stiffnesses significantly lower (50% less) than either piezoceramic device. This suggests that single-crystal piezocomposite actuators will be best suited to low induced-stress, high strain and deflection applications.

Pediatric Perimeter—A Novel Device to Measure Visual Fields in Infants and Patients with Special Needs

PubMed Central

Satgunam, PremNandhini; Datta, Sourav; Chillakala, Koteswararao; Bobbili, Karthik R.; Joshi, Dhruv

2017-01-01

Purpose There are no commercially available devices to measure visual fields in infants. We developed a device, “Pediatric Perimeter,” that quantifies visual field extent (VFE) for infants. We describe the construction, validation, and use of this device. Methods A hemispherical dome with light emitting diodes (LEDs) was constructed. The LEDs were controlled using a computer program to measure reaction time (RT) to gross visual fields (GVF) and the VFE. Participants were tested in supine position in a dark room. Eye or head movement towards the stimuli was monitored with an infrared (IR) camera. Validation was done on 10 adults (mean age: 24.4 ± 5 years) with tunnel vision simulator. Results Perimetry was performed on 19 infants (age: 2.3–12 months), five infants with normal milestones. GVF and VFE were estimated in 17 and 7 infants, respectively. Median RT of infants with developmental delay was 663 ms and 380 ms for healthy infants. Also, 14 children (age: 14 months–6 years) with developmental delay and five patients with cognitive impairment were tested. Conclusion Visual field isopter and RT can be examined with the Pediatric Perimeter device on infants and patients with special needs. Further testing on infants will need to assess the repeatability. A large-scale study will be needed to compare typically developing infants and infants with delayed milestones with this device. Translational Relevance Quantifiable parameters obtained with this device can be used as outcome measures in clinical examination of infants and patients with special needs. This device can be used in pediatric, neurology, and ophthalmology clinics. PMID:28685105

Hand skill measurement: a gauge for treatment.

PubMed

Bell, E; Jurek, K; Wilson, T

1976-02-01

Objective measurements of performance are vital with the increasing necessity to justify the need for occupational therapy services, and to conduct studies that measure the effectiveness of treatment procedures. This paper reports on a measurement of hand skill that was standardized by comparing hand skill performance among the able-bodied, or normal, population. The performance on this test o patients with various types of disabilities and the implications for treatment are discussed. For the paraplegic, the hand skill test indicates the need for occupational therapy services; for the quadriplegic, the test measures the effectiveness of functional orthotic devices; and for the hemiplegic, the hand skill test determines the potential for success in one aspect of self-care, dressing.

Fibre optic sensors for temperature and pressure monitoring in laser ablation: experiments on ex-vivo animal model

NASA Astrophysics Data System (ADS)

Tosi, Daniele; Saccomandi, Paola; Schena, Emiliano; Duraibabu, Dinesh B.; Poeggel, Sven; Adilzhan, Abzal; Aliakhmet, Kamilla; Silvestri, Sergio; Leen, Gabriel; Lewis, Elfed

2016-05-01

Optical fibre sensors have been applied to perform biophysical measurement in ex-vivo laser ablation (LA), on pancreas animal phantom. Experiments have been performed using Fibre Bragg Grating (FBG) arrays for spatially resolved temperature detection, and an all-glass Extrinsic Fabry-Perot Interferometer (EFPI) for pressure measurement. Results using a Nd:YAG laser source as ablation device, are presented and discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Li; Zhu, Zihua; Yu, Xiao-Ying

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a unique surface analysis technique because it can provide molecular recognition for organic and biological molecules. However, analyzing aqueous solution surfaces by ToF-SIMS is difficult, because ToF-SIMS is a high-vacuum technique, while the vapor pressure of water is about 2.3 kPa at room temperature (20 C). We designed and fabricated a self-contained microfluidic device, enabling in situ analysis of aqueous surfaces by scanning electron microscope (SEM) and ToF-SIMS, which has been briefly reported.1,2 In this study, we report more performance data, focusing on the performance of this device for in situ analysis ofmore » organic molecules at aqueous surfaces using ToF-SIMS. Three representative organic compounds (formic acid, glycerol, and glutamic acid) were tested, and their molecular signals were successfully observed. The device can be self-running in vacuum for 8 hours, and SIMS measurements are feasible at any time in this time range. The stability of this device under primary ion beam bombardment is also impressive. High fluence (6 × 1012 ions cm-2 s-1) measurements can be operated continuously for up to 30 minutes without any significant damage to the aperture. However, extra-high fluence measurements (>1 × 1014 ions cm-2 s-1) may lead to liquid bumping in the aperture, and the aqueous solutions may spread out quickly. Signal reproducibility is reasonably good, and relative standard deviation (RSD) for molecular ion signals can be controlled to be smaller than ±15% for consecutive measurements. Measurements at long time intervals (e.g., 60 min) show RSDs of ±40-50%. In addition, the detection limits of formic acid, glycerol, and glutamic acid are estimated to be 0.04%, 0.008%, and 0.002% (weight ratio), respectively.« less

Optical and dark characterization of the PLATO CCD at ESA

NASA Astrophysics Data System (ADS)

Verhoeve, Peter; Prod'homme, Thibaut; Oosterbroek, Tim; Duvet, Ludovic; Beaufort, Thierry; Blommaert, Sander; Butler, Bart; Heijnen, Jerko; Lemmel, Frederic; van der Luijt, Cornelis; Smit, Hans; Visser, Ivo

2016-07-01

PLATO - PLAnetary Transits and Oscillations of stars - is the third medium-class mission (M3) to be selected in the European Space Agency (ESA) Science and Robotic Exploration Cosmic Vision programme. It is due for launch in 2025 with the main objective to find and study terrestrial planets in the habitable zone around solar-like stars. The payload consists of >20 cameras; with each camera comprising 4 Charge-Coupled Devices (CCDs), a large number of flight model devices procured by ESA shall ultimately be integrated on the spacecraft. The CCD270 - specially designed and manufactured by e2v for the PLATO mission - is a large format (8 cm x 8 cm) back-illuminated device operating at 4 MHz pixel rate and coming in two variants: full frame and frame transfer. In order to de-risk the PLATO CCD procurement and aid the mission definition process, ESA's Payload Technology Validation section is currently validating the PLATO CCD270. This validation consists in demonstrating that the device achieves its specified electrooptical performance in the relevant environment: operated at 4 MHz, at cold and before and after proton irradiation. As part of this validation, CCD270 devices have been characterized in the dark as well as optically with respect to performance parameters directly relevant for the photometric application of the CCDs. Dark tests comprise the measurement of gain sensitivity to bias voltages, charge injection tests, and measurement of hot and variable pixels after irradiation. In addition, the results of measurements of Quantum Efficiency for a range of angles of incidence, intra- pixel response (non-)uniformity, and response to spot illumination, before and after proton irradiation. In particular, the effect of radiation induced degradation of the charge transfer efficiency on the measured charge in a star-like spot has been studied as a function of signal level and of position on the pixel grid, Also, the effect of various levels of background light on the amount of charge lost from a star image are described. These results can serve as a direct input to the PLATO consortium to study the mission performance and as a basis for further optimization of the CCD operation.

Performance Assessment of Active Hearing Protection Devices

DTIC Science & Technology

2015-05-08

8 Figure 6. Placement of ATFs and free -field pressure transducer ....................................... 8 Figure 7. Pressure-time history...devices selected for this study were all equipped with a hear-thru setting designed to amplify soft sounds and conversational speech while allowing loud...duration of an impulse noise A ¼” microphone or slender probe (tapered pencil gauge) was used to measure the free - field pressure wave according to the

40 CFR Table 4 to Subpart Zzzz of... - Requirements for Performance Tests

Code of Federal Regulations, 2010 CFR

2010-07-01

... and outlet of the control device; and (1) Portable CO and O2 analyzer. (a) Using ASTM D6522-00 (2005... control device (1) Portable CO and O2 analyzer. (a) Using ASTM D6522-00 (2005) a,b (incorporated by..., appendix A, or ASTM Method D6522-00 (2005) (a) Measurements to determine O2 concentration must be made at...

Superconducting hot electron bolometers for terahertz sensing

NASA Astrophysics Data System (ADS)

Reese, Matthew Owen

Superconducting Hot Electron Bolometers (HEBs) are good candidates for detecting weak signals in the submillimeter or terahertz range. In this thesis work, a novel fabrication method was developed to make two types of niobium HEBs for different applications. HEBs were designed, fabricated, and then characterized at dc, microwave, and THz frequencies. The first type is a diffusion-cooled HEB, made with a short bridge that determines its cooling time. In this thesis, bridges were typically 400 nm long with bandwidths of about 1 GHz. These diffusion-cooled HEBs were developed as part of a collaboration with the University of Arizona (UA), to develop a proof-of-concept heterodyne array submillimeter camera. Devices were fabricated on thin fused quartz and silica substrates for waveguide coupling in the UA system for the astrophysically interesting 345 and 810 GHz atmospheric windows. The goal of this collaboration is to provide a basis of comparison between Nb diffusion-cooled HEB mixers and superconductorinsulator-superconductor mixers at these frequencies. The second type is a phonon-cooled HEB, made with a ˜3 mum long bridge. Its thermal response is dictated by the electron-phonon relaxation time. These devices were developed in collaboration with Prof. C. Schmuttenmaer's lab in the Yale Chemistry department, Prof. G. Blake at Caltech, and Dr. J. Pearson at the Jet Propulsion Laboratory. These devices were developed for use in quasi-optic systems to be used as fast (>100 MHz) direct detectors that can view room temperature sources without saturating. A variety of experimental applications are envisioned for these detectors including charge transport measurements of novel materials. A series of dc and microwave measurements were performed on the diffusion-cooled devices. A better understanding of the resistance vs. temperature profile was realized, including what design/fabrication parameters affect it and insight into how it affects device performance. This led to a do screening process that can identify good quality devices. The Nb phonon-cooled HEBs studied in this thesis were fully carried through the design, fabrication, and characterization process at dc, microwave and THz frequencies. The saturation power, responsivity, thermal response time, and noise performance were all measured to be within the expected range predicted by the initial design parameters.

Local Imaging of Optoelectronic Properties and Film Degradation in Polymer/Fullerene Solar Cells with Electrostatic Force Microscopy

NASA Astrophysics Data System (ADS)

Cox, Phillip Alexander

With power conversion efficiencies on the rise, organic photovoltaics (OPVs) hold promise as a next-generation thin-film solar technology. However, both device performance and stability are inextricably linked to local film structure. Methods capable of probing nanoscale electronic properties as a function of film structure are thus a crucial component of the rational design of efficient and robust devices. This dissertation describes the use of three scanning probe methods for studying local charge generation and photodegradation in polymer/fullerene solar cells. First, we show that time-resolved electrostatic force microscopy (trEFM) is capable of resolving local photocurrent from sub-bandgap excitation down to attoampere level currents, a result unattainable by traditional contact-mode methods. We find that the local charging rates measured with trEFM are proportional to external quantum efficiency (EQE) measurements made on completed devices, making trEFM images equivalent to local EQE maps across the entire solar spectrum. For both phase-segregated and well-mixed MDMO-PPV:PCBM film morphologies, we show that the local distribution of photocurrent is invariant to excitation wavelength, providing local evidence for the controversial result that the probability of generating separated charge carriers does not depend on whether excitons are formed at the singlet state or charge transfer state. Next, we describe how local dissipation imaging can be performed with commercially-available frequency-modulated electrostatic force microscopy (FM-EFM) and show that dissipation maps are highly sensitive to photo-oxidative effects in organic semiconductors. We show that photo-oxidation induced changes in cantilever energy dissipation are proportional to device performance losses. We further develop dissipation imaging by implementing ringdown imaging, which directly measures the quality factor of the cantilever, enabling quantitative dissipation mapping. Using organic photovoltaic materials as a testbed, we study macroscopic device degradation as a function of photooxidation for three different film morphologies. According to EQE measurements, we find that the stability of the macroscopic devices is very sensitive to processing conditions, with films processed with the solvent additive 1,8-diiodooctane being the most stable. At the microscopic level, we compare the evolution of cantilever power dissipation as a function of photochemical degradation for three different polymer/fullerene blend morphologies, and show that the evolution of local power dissipation correlates with device stability. Lastly, we show that cantilever power dissipation increases more rapidly over large fullerene aggregates than in well-mixed polymer/fullerene regions, suggesting that local photochemistry on the fullerene contributes strongly to the dissipation signal.

Storm wave buoy equipped with micromechanical inertial unit: Results of development and testing

NASA Astrophysics Data System (ADS)

Gryazin, D. G.; Staroselcev, L. P.; Belova, O. O.; Gleb, K. A.

2017-07-01

The article describes the results of developing a wave buoy to measure the statistical characteristics of waves and the characteristics of directional spectra of three-dimensional waves. The device is designed for long-term measurements lasting up to a season, which can help solve problems in forecasting waves and preventing emergencies from wave impact on offshore platforms, hydraulic structures, and other marine facilities. The measuring unit involves triads of micromechanical gyroscopes, accelerometers, and a three-component magnetometer. A description of the device, results of laboratory research of its characteristics, and bench and full-scale tests are offered. It is noted that to assess the performance characteristics, comparative tests of the Storm wave buoy were conducted with a standard string wave probe installed on an offshore platform. It is shown that the characteristics and capabilities of the wave buoy make it possible to oust foreign devices from the domestic market.

Testing a Method for Quantifying the Output of Implantable Middle Ear Hearing Devices

PubMed Central

Rosowski, J.J.; Chien, W.; Ravicz, M.E.; Merchant, S.N.

2008-01-01

This report describes tests of a standard practice for quantifying the performance of implantable middle ear hearing devices (also known as implantable hearing aids). The standard and these tests were initiated by the Food and Drug Administration of the United States Government. The tests involved measurements on two hearing devices, one commercially available and the other home built, that were implanted into ears removed from human cadavers. The tests were conducted to investigate the utility of the practice and its outcome measures: the equivalent ear canal sound pressure transfer function that relates electrically driven middle ear velocities to the equivalent sound pressure needed to produce those velocities, and the maximum effective ear canal sound pressure. The practice calls for measurements in cadaveric ears in order to account for the varied anatomy and function of different human middle ears. PMID:17406105

Low-background performance of a monolithic InSb CCD array

NASA Technical Reports Server (NTRS)

Bregman, J. D.; Goebel, J. H.; Mccreight, C. R.; Matsumoto, T.

1982-01-01

A 20 element monolithic InSb charge coupled device (CCD) detector array was measured under low background conditions to assess its potential for orbital astronomical applications. At a temperature of 64 K, previous results for charge transfer efficiency (CTE) were reproduced, and a sensitivity of about 2 x 10 to the minus 15th power joules was measured. At 27 and 6 K, extended integration times were achieved, but CTE was substantially degraded. The noise was approximately 6000 charges, which was in excess of the level where statistical fluctuations from the illumination could be detected. A telescope demonstration was performed showing that the array sensitivity and difficulty of operation were not substantially different from laboratory levels. Ways in which the device could be improved for astronomical applications were discussed.

Multiple benefits of personal FM system use by children with auditory processing disorder (APD).

PubMed

Johnston, Kristin N; John, Andrew B; Kreisman, Nicole V; Hall, James W; Crandell, Carl C

2009-01-01

Children with auditory processing disorders (APD) were fitted with Phonak EduLink FM devices for home and classroom use. Baseline measures of the children with APD, prior to FM use, documented significantly lower speech-perception scores, evidence of decreased academic performance, and psychosocial problems in comparison to an age- and gender-matched control group. Repeated measures during the school year demonstrated speech-perception improvement in noisy classroom environments as well as significant academic and psychosocial benefits. Compared with the control group, the children with APD showed greater speech-perception advantage with FM technology. Notably, after prolonged FM use, even unaided (no FM device) speech-perception performance was improved in the children with APD, suggesting the possibility of fundamentally enhanced auditory system function.

Imaging visible light with Medipix2.

PubMed

Mac Raighne, Aaron; Brownlee, Colin; Gebert, Ulrike; Maneuski, Dzmitry; Milnes, James; O'Shea, Val; Rügheimer, Tilman K

2010-11-01

A need exists for high-speed single-photon counting optical imaging detectors. Single-photon counting high-speed detection of x rays is possible by using Medipix2 with pixelated silicon photodiodes. In this article, we report on a device that exploits the Medipix2 chip for optical imaging. The fabricated device is capable of imaging at >3000 frames/s over a 256×256 pixel matrix. The imaging performance of the detector device via the modulation transfer function is measured, and the presence of ion feedback and its degradation of the imaging properties are discussed.

High-fidelity digital recording and playback sphygmomanometry system: device description and proof of concept.

PubMed

Lee, Jongshill; Chee, Youngjoon; Kim, Inyoung; Karpettas, Nikos; Kollias, Anastasios; Atkins, Neil; Stergiou, George S; O'Brien, Eoin

2015-10-01

This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study. A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated. The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP). The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.

Using grasping tasks to evaluate hand force coordination in children with hemiplegic cerebral palsy.

PubMed

Mackenzie, Samuel J; Getchell, Nancy; Modlesky, Christopher M; Miller, Freeman; Jaric, Slobodan

2009-08-01

Mackenzie SJ, Getchell N, Modlesky CM, Miller F, Jaric S. Using grasping tasks to evaluate hand force coordination in children with hemiplegic cerebral palsy. To assess force coordination in children with hemiplegic cerebral palsy (CP) using a device that allows for testing both unimanual and bimanual manipulation tasks performed under static and dynamic conditions. Nonequivalent groups design. University research laboratory for motor control. Six children with hemiplegic CP (age, mean +/- SD, 11.6+/-1.8 y) and 6 typically developing controls (11.6+/-1.6 y). Not applicable. Children performed simple lifting and force-matching static ramp tasks by way of both unimanual and bimanual pulling using a device that measures grip force (force acting perpendicularly at the digits-device contact area) and load force (tangential force). Main outcome measures were grip/load force ratios (grip force scaling) and correlation coefficients (force coupling). CP subjects showed significantly higher grip/load force ratios (P<.05) and slightly lower correlation coefficients than the control group, with more pronounced differences for most tasks when using their involved hand. For subjects with CP, switching from unimanual to bimanual conditions did not bring changes in scaling or coupling for the involved hand (P>.05). Compared with healthy children, the impaired hand function in the hemiplegic CP pediatric population could be reflected in excessive grip force that is also decoupled from ongoing changes in load force. Therefore, the bimanual grip load device used in this study could provide a sensitive measure of grip force coordination in CP, although nonmotor deficits should be taken into account when asking children to perform more complex tasks.

Development and Validation of a Rapid (13)C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices.

PubMed

Matsunami, Risë K; Angelides, Kimon; Engler, David A

2015-05-18

There is currently considerable discussion about the accuracy of blood glucose concentrations determined by personal blood glucose monitoring systems (BGMS). To date, the FDA has allowed new BGMS to demonstrate accuracy in reference to other glucose measurement systems that use the same or similar enzymatic-based methods to determine glucose concentration. These types of reference measurement procedures are only comparative in nature and are subject to the same potential sources of error in measurement and system perturbations as the device under evaluation. It would be ideal to have a completely orthogonal primary method that could serve as a true standard reference measurement procedure for establishing the accuracy of new BGMS. An isotope-dilution liquid chromatography/mass spectrometry (ID-UPLC-MRM) assay was developed using (13)C6-glucose as a stable isotope analogue to specifically measure glucose concentration in human plasma, and validated for use against NIST standard reference materials, and against fresh isolates of whole blood and plasma into which exogenous glucose had been spiked. Assay performance was quantified to NIST-traceable dry weight measures for both glucose and (13)C6-glucose. The newly developed assay method was shown to be rapid, highly specific, sensitive, accurate, and precise for measuring plasma glucose levels. The assay displayed sufficient dynamic range and linearity to measure across the range of both normal and diabetic blood glucose levels. Assay performance was measured to within the same uncertainty levels (<1%) as the NIST definitive method for glucose measurement in human serum. The newly developed ID UPLC-MRM assay can serve as a validated reference measurement procedure to which new BGMS can be assessed for glucose measurement performance. © 2015 Diabetes Technology Society.

Development and Validation of a Rapid 13C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices

PubMed Central

Matsunami, Risë K.; Angelides, Kimon; Engler, David A.

2015-01-01

Background: There is currently considerable discussion about the accuracy of blood glucose concentrations determined by personal blood glucose monitoring systems (BGMS). To date, the FDA has allowed new BGMS to demonstrate accuracy in reference to other glucose measurement systems that use the same or similar enzymatic-based methods to determine glucose concentration. These types of reference measurement procedures are only comparative in nature and are subject to the same potential sources of error in measurement and system perturbations as the device under evaluation. It would be ideal to have a completely orthogonal primary method that could serve as a true standard reference measurement procedure for establishing the accuracy of new BGMS. Methods: An isotope-dilution liquid chromatography/mass spectrometry (ID-UPLC-MRM) assay was developed using 13C6-glucose as a stable isotope analogue to specifically measure glucose concentration in human plasma, and validated for use against NIST standard reference materials, and against fresh isolates of whole blood and plasma into which exogenous glucose had been spiked. Assay performance was quantified to NIST-traceable dry weight measures for both glucose and 13C6-glucose. Results: The newly developed assay method was shown to be rapid, highly specific, sensitive, accurate, and precise for measuring plasma glucose levels. The assay displayed sufficient dynamic range and linearity to measure across the range of both normal and diabetic blood glucose levels. Assay performance was measured to within the same uncertainty levels (<1%) as the NIST definitive method for glucose measurement in human serum. Conclusions: The newly developed ID UPLC-MRM assay can serve as a validated reference measurement procedure to which new BGMS can be assessed for glucose measurement performance. PMID:25986627

SU-C-201-05: Silicon Array Dosimeter in Situ with Electronic Portal Image Device for Simultaneous Transit Dose and Image Verification in Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deshpande, S; Alhujaili, S; Vial, P

Purpose: To investigate an Electronic Portal Imaging Device (EPID) coupled to a 2D array dosimeter to provide simultaneous imaging and dose verification. Methods: The novel dual detector configuration comprised of a 2D diode array dosimeter, referred to as a Magic Plate (MP) placed directly on a standard EPID. Dose response of the MP was evaluated by measuring the detector’s response with respect to off-axis position and field size with 30 cm of solid water (SW) acting as a transit object in the beam. Measurements were performed with 3, 5, 10 and 15 mm SW build-up and compared to 2D ionisationmore » chamber array (ICA) measurements and the PinnacleTM treatment planning system (TPS) at a source to detector distance of 150 cm with a 6 MV beam. Clinical dosimetric performance was evaluated by measuring a number of intensity-modulated radiation therapy (IMRT) beams in transit geometry. Imaging performance of the EPID was quantified by measuring the contrast-to-noise ratio (CNR) and spatial resolution. Images of a Rando phantom were used for qualitative assessment. Results: Measured MP off-axis and field size response agreed within 2% of TPS and ICA responses when measured using 15 mm SW build-up. Clinical IMRT beams had gamma pass rates of ≥95% at 3%/3mm criteria. Measured CNR and spatial resolution (f50) were 264.96, 210.6, and 0.41, 0.40 with build-up of 5 and 15 mm respectively for the dual detector configuration. CNR and spatial resolution of 643.9 and 0.41 were measured for standard EPID. CNR was quantitatively worse in the dual detector configuration. Differences in imaging performance were not visible in a qualitative assessment using a Rando phantom. Conclusion: Combining a prototype MP 2D dosimeter with a conventional EPID did not significantly detract from the performance of either device and has the potential for simultaneous on-line patient transit dosimetry and image assessment in radiation therapy. Cancer Institute NSW Australia(Research Equipment Grant 10/REG/1-20) and Cancer Council NSW (Grant ID RG 1-06)« less

Step-response of a torsional device with multiple discontinuous non-linearities: Formulation of a vibratory experiment

NASA Astrophysics Data System (ADS)

Krak, Michael D.; Dreyer, Jason T.; Singh, Rajendra

2016-03-01

A vehicle clutch damper is intentionally designed to contain multiple discontinuous non-linearities, such as multi-staged springs, clearances, pre-loads, and multi-staged friction elements. The main purpose of this practical torsional device is to transmit a wide range of torque while isolating torsional vibration between an engine and transmission. Improved understanding of the dynamic behavior of the device could be facilitated by laboratory measurement, and thus a refined vibratory experiment is proposed. The experiment is conceptually described as a single degree of freedom non-linear torsional system that is excited by an external step torque. The single torsional inertia (consisting of a shaft and torsion arm) is coupled to ground through parallel production clutch dampers, which are characterized by quasi-static measurements provided by the manufacturer. Other experimental objectives address physical dimensions, system actuation, flexural modes, instrumentation, and signal processing issues. Typical measurements show that the step response of the device is characterized by three distinct non-linear regimes (double-sided impact, single-sided impact, and no-impact). Each regime is directly related to the non-linear features of the device and can be described by peak angular acceleration values. Predictions of a simplified single degree of freedom non-linear model verify that the experiment performs well and as designed. Accordingly, the benchmark measurements could be utilized to validate non-linear models and simulation codes, as well as characterize dynamic parameters of the device including its dissipative properties.

View of FE Stott using the BMMD in the SM

NASA Image and Video Library

2009-10-12

ISS021-E-014503 (12 Oct. 2009) --- NASA astronaut Nicole Stott, Expedition 21 flight engineer, uses the IM mass measurement device to perform the PZEh-MO-8/Body Mass Measurement Russian biomedical routine assessments in the Zvezda Service Module of the International Space Station.

Hot spot dynamics in carbon nanotube array devices.

PubMed

Engel, Michael; Steiner, Mathias; Seo, Jung-Woo T; Hersam, Mark C; Avouris, Phaedon

2015-03-11

We report on the dynamics of spatial temperature distributions in aligned semiconducting carbon nanotube array devices with submicrometer channel lengths. By using high-resolution optical microscopy in combination with electrical transport measurements, we observe under steady state bias conditions the emergence of time-variable, local temperature maxima with dimensions below 300 nm, and temperatures above 400 K. On the basis of time domain cross-correlation analysis, we investigate how the intensity fluctuations of the thermal radiation patterns are correlated with the overall device current. The analysis reveals the interdependence of electrical current fluctuations and time-variable hot spot formation that limits the overall device performance and, ultimately, may cause device degradation. The findings have implications for the future development of carbon nanotube-based technologies.