Optical PIV and LDV Comparisons of Internal Flow Investigations in SHF Impeller

Directory of Open Access Journals (Sweden)

G. Wuibaut

2006-01-01

Full Text Available The paper presents a comparison between two sets of experimental results in a centrifugal flow pump. The tested impeller is the so-called SHF impeller for which many experimental data have been continuously produced to built databases for CFD code validations with various levels of approximation. Measurements have been performed using optical techniques: 2D particle image velocimetry (PIV technique on an air test model and 2D laser doppler velocimetry (LDV technique on a water model, both for different flow rates. For the present study, results obtained by these optical techniques are compared together in terms of phase averaged velocity and velocity fluctuations inside the impeller flow passage for design flow rate.

[LenSx® femto-LASIK, FEMTO LDV Z4® femto-LASIK, and PRK : Comparison of refractive results and an analysis of complications].

Science.gov (United States)

Pahlitzsch, T; Pahlitzsch, M-L; Sumarni, U; Pahlitzsch, M

2017-10-30

The aim of this study is to evaluate three refractive procedures: LenSx® (Alcon, Fort Worth, TX, USA) femto-laser in situ keratomileusis (LASIK), FEMTO LDV Z4® (Ziemer, Port, Switzerland) femto-LASIK, and photorefractive keratectomy (PRK) in terms of refractive outcome, perioperative complications, pain, and patient satisfaction. Data of 168 eyes (myopic n = 84) were included in this retrospective study. Of these, 54 eyes (n = 27, 33.85 ± 7.64 years) were treated with LenSx® femto-LASIK, 60 eyes (n = 30, 35.03 ± 7.46 years) with FEMTO LDV Z4® femto-LASIK, and 54 eyes (n = 27, 33.24 ± 8.52 years) with PRK. Photoablation was induced by a MEL80 Excimerlaser (Zeiss, Oberkochen, Germany). The corrected (V sc ) and uncorrected (V cc ) distance subjective visual acuity, corneal topography (Pentacam® HR; Wetzlar, Germany), and objective astigmatism (ARK-760A Refractometer ; Nidek, Fremont, CA, USA) were measured preoperatively, and 1 day, 1 week, 1 month, and 3 months postoperatively. Subjective pain (verbal rating scale) and patient satisfaction were also recorded. Subjective V sc showed significantly better results in both femto-LASIK cohorts compared to PRK (p PRK cohorts (p = 0.072). LDV Z4® femto-LASIK showed the lowest pain score 1 day postoperatively (p PRK. There is no difference between the three techniques regarding refractive outcome after 3 months follow-up. LDV Z4® femto-LASIK can be recommended, if available, due to its low intraoperative complication rate and higher patient satisfaction compared to LenSx® femto-LASIK.

Laser in situ keratomileusis enhancements with the Ziemer FEMTO LDV femtosecond laser following previous LASIK treatments.

Science.gov (United States)

Pietilä, Juhani; Huhtala, Anne; Mäkinen, Petri; Uusitalo, Hannu

2013-02-01

The aim of this paper is to present the accuracy, predictability, and safety outcomes of LASIK enhancements performed with the FEMTO LDV femtosecond laser (Ziemer Ophthalmic Systems, Port, Switzerland) and the Allegretto Wave Concerto 500 Hz excimer laser (Wavelight AG, Erlangen, Germany), following previous LASIK treatments. FEMTO LDV was used for flap creation in 85 previously LASIK-treated eyes of 62 patients. The intended flap thickness was 90 μm in 81 eyes and 140 μm in 4 eyes. The size of the suction ring was 9.0 mm in 72 eyes and 9.5 mm in 13 eyes. Flap dimensions were measured and correlated to preoperative characteristics. With the intended flap thickness of 90 μm in previously LASIK-treated eyes, the actual flap thickness was 90.2 ± 6.6 μm (range 80-122), and the flap diameter was 9.2 ± 0.2 mm (range 8.7-9.9). The mean hinge length was 4.0 ± 0.2 mm (range 3.0-4.8). Flap thickness correlated positively with patient age and hinge length. Complications were reported in 12 eyes (14.1 %). Most of the complications were very mild, and none of them prevented further refractive laser treatment. One eye lost two Snellen lines of best spectacle-corrected visual acuity. Femtosecond LASIK enhancement is warranted only in rare cases. Surgical experience is needed and special caution must be practiced. For cases of a primary free cap, femtosecond LASIK is not recommended.

Joint High Speed Sealift (JHSS) Baseline Shaft & Strut (BSS) Model 5653-3: Series 2, Propeller Disk LDV Wake Survey; and Series 3, Stock Propeller Powering and Stern Flap Evaluation Experiments

National Research Council Canada - National Science Library

Cusanelli, Dominic S; Chesnakas, Christopher J

2007-01-01

...) and Stock Propeller Powering and Stern Flap Evaluation tests (Series 3. In order to assist in the design of a propeller for the BSS hull, the nominal wakes in the inboard and outboard starboard propeller planes were measured using LDV...

Development of remote vibration measurement technique through turbulent media

Energy Technology Data Exchange (ETDEWEB)

Baik, Sung Hoon; Chung, Chin Man; Kim, Min Suk; Park, Seung Kyu; Chung, Heung Jone

2002-12-01

The effect of wavefront distortion of laser beam of a LDV(Laser Doppler Vibrometer) in the turbulence media was investigated for application of adaptive optics to LDV. The high-speed tip/tilt adaptive optics system and closed-loop steering algorithm were developed for real-time correction of the direction fluctuation of the laser beam of LDV. The measuring performance of the LDV was improved when the steering system was applied to LDV at the vibration frequency range of 10 Hz - 30 Hz. The high-speed Shack-Hartmann wavefront sensor(400 Hz) was developed to measure the performance of the LDV due to wavefront distortion. The wavefront distortion due to the turbulence media induced low visibility and degraded the performance of the vibrometer. From the experiments, when the wavefront distortion is above 2 wavelengths in the cross section of the laser beam(dia. 20 mm), the vibration signal from laser vibrometer was severely degraded. When the wavefront distortion is smaller than one wave, the vibration signal was good. From the this research, high-speed closed-loop tip/tilt control technique of the laser beam was developed and applied to the laser metrology area. In the future, the adaptive optics system for wavefront correction will be applied to other research area.

Application of a Novel Laser-Doppler Velocimeter for Turbulence: Structural Measurements in Turbulent Boundary Layers

National Research Council Canada - National Science Library

Lowe, Kevin T; Simpson, Roger L

2006-01-01

An advanced laser-Doppler velocimeter (LDV), deemed the 'comprehensive LDV', is designed to acquire fully-resolved turbulence structural measurements in high Reynolds number two- and three-dimensional turbulent boundary layers...

Scan posture definition and hip girth measurement: the impact on clothing design and body scanning.

Science.gov (United States)

Gill, Simeon; Parker, Christopher J

2017-08-01

Ergonomic measurement is central to product design and development; especially for body worn products and clothing. However, there is a large variation in measurement definitions, complicated by new body scanning technology that captures measurements in a posture different to traditional manual methods. Investigations of hip measurement definitions in current clothing measurement practices supports analysis of the effect of scan posture and hip measurement definition on the circumferences of the hip. Here, the hip girth is a key clothing measurement that is not defined in current body scanning measurement standards. Sixty-four participants were scanned in the standard scan posture of a [TC] 2 body scanner, and also in a natural posture similar to that of traditional manual measurement collection. Results indicate that scan posture affects hip girth circumferences, and that some current clothing measurement practices may not define the largest lower body circumference. Recommendations are made concerning how the hip is defined in measurement practice and within body scanning for clothing product development. Practitioner Summary: The hip girth is an important measurement in garment design, yet its measurement protocol is not currently defined. We demonstrate that body posture during body scanning affects hip circumferences, and that current clothing measurement practices may not define the largest lower body circumference. This paper also provides future measurement practice recommendations.

Influence of laser frequency noise on scanning Fabry-Perot interferometer based laser Doppler velocimetry

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2014-01-01

n this work, we study the performance of a scanning Fabry-Perot interferometer based laser Doppler velocimeter (sFPILDV) and compare two candidate 1.5 um single-frequency laser sources for the system – a fiber laser (FL) and a semiconductor laser (SL). We describe a straightforward calibration...... procedure for the sFPI-LDV and investigate the effect of different degrees of laser frequency noise between the FL and the SL on the velocimeter’s performance...

DepositScan, a Scanning Program to Measure Spray Deposition Distributions

Science.gov (United States)

DepositScan, a scanning program was developed to quickly measure spray deposit distributions on water sensitive papers or Kromekote cards which are widely used for determinations of pesticide spray deposition quality on target areas. The program is installed in a portable computer and works with a ...

Assessment of dose measurement uncertainty using RisoScan

International Nuclear Information System (INIS)

Helt-Hansen, Jakob; Miller, Arne

2006-01-01

The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4%, respectively, at one standard deviation. The subroutine in RisoScan for electron energy measurement is shown to give results that are equivalent to the measurements with a scanning spectrophotometer

Fuel Rod Vibration Measurement Method using a Flap and its Verification

Energy Technology Data Exchange (ETDEWEB)

Yoo, Joo Young; Park, Nam Gyu; Suh, Jung Min; Jeon, Kyeong Lak [KEPCO NF Co., Daejeon (Korea, Republic of)

2011-10-15

Flow-induced vibration is a critical factor for the mechanical integrity of a fuel rod. This vibration can cause leaked fuel through the mechanism, such as grid to rod fretting. To minimize the failures caused by flow-induced vibration, a robust design is needed which takes into account vibrational characteristics. That is, the spacer grid design should be developed to avoid any excessive vibration. On the one hand, if fuel rod vibration can be measured, an estimation of the excitation forces, which are a critical cause of rod failure, should be possible. Therefore, by applying an external force, flow-induced vibration can be roughly estimated when the fuel rod vibration model is used. KEPCO Nuclear Fuel developed the test loop to research flow-induced vibration as shown in Fig.1. The investigation flow-induced vibration (INFINIT) - the test facility - can measure the grid strap vibration and pressure drop of a 5x5 small scale fuel bundle. Basically, using a Laser Doppler Vibrometer (LDV), the vibration of a structure immersed in high speed fluid can be measured. Grid strap vibration is easily measured using an LDV. However, it is quite difficult to measure fuel rod vibration because of the round surface shape of the rods. In addition, measuring current method using the LDV, it was only possible to directly measure fuel rod vibration at the first row of the bundle as the rods behind the first row are obscured. To solve this problem, a thin flap, as shown in Fig. 2(a) can be used as a reflecting target, gaining access to rods within the bundle. The flap is attached to the fuel rod, as in Fig. 2(b). As a result, most of the inner rod vibration can be measured. Before using a flap to measure fuel rod vibration, a verification process was needed to show whether the LDV signal from the flap vibration provided equivalent and reliable signals. Therefore, impact testing was carried out on the fuel rod using a flap. The LDV signals were then compared with accelerometer

Dialogue scanning measuring systems

International Nuclear Information System (INIS)

Borodyuk, V.P.; Shkundenkov, V.N.

1985-01-01

The main developments of scanning measuring systems intended for mass precision processsing of films in nuclear physics problems and in related fields are reviewed. A special attention is paid to the problem of creation of dialogue systems which permit to simlify the development of control computer software

THE APPLICATION OF LASERS IN MEASUREMENT OF FLUID FLOW THROUGH DRILLING BIT NOZZLES

Directory of Open Access Journals (Sweden)

Radenko Drakulić

1993-12-01

Full Text Available Two optical methods based on laser and video technology and digital signal and image processing techniques - Laser Doppler velocimetry (LDV and Particle image velocimetry (PIV were applied in highly accurate fluid flow measurement. Their application in jet velocity measurement of flows through drilling bit nozzles is presented. The role of nozzles in drilling technology together with procedures and tests performed on their optimization are reviewed. In addition, some experimental results for circular nozzle obtained both with LDV and PIV are elaborated. The experimental set-up and the testing procedure arc briefly discussed, as well as potential improvements in the design. Possible other applications of LDV and PIV in the domain of petroleum engineering are suggested (the paper is published in Croatian.

Assessment of dose measurement uncertainty using RisøScan

DEFF Research Database (Denmark)

Helt-Hansen, J.; Miller, A.

2006-01-01

The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4%, respectiv......%, respectively, at one standard deviation. The subroutine in RisoScan for electron energy measurement is shown to give results that are equivalent to the measurements with a scanning spectrophotometer. (c) 2006 Elsevier Ltd. All rights reserved....

Comparison of intraocular pressure during the application of a liquid patient interface (FEMTO LDV Z8) for femtosecond laser-assisted cataract surgery using two different vacuum levels.

Science.gov (United States)

Ebner, Martina; Mariacher, Siegfried; Januschowski, Kai; Boden, Katrin; Seuthe, Anna-Maria; Szurman, Peter; Boden, Karl Thomas

2017-08-01

To evaluate intraocular pressure (IOP) using the application of a novel liquid patient interface for femtosecond laser-assisted cataract surgery with the FEMTO LDV Z8. IOP was evaluated in enucleated porcine eyes prior, during and after the application of the Femto LDV Z8 liquid patient interface (Ziemer Ophthalmic Systems, Switzerland) using intracameral cannulation (n=20), intravitreal cannulation (n=20), rebound tonometry (n=20) and indentation tonometry (n=20). Pressure was assessed prior vacuum, during vacuum (30 s, 1 min, 2 min, 3 min) and after releasing the vacuum (1 min and 2 min). Two groups with different predefined vacuum levels (350 mbar, 420 mbar) were investigated. Mean intracameral pressure (±SD) increased during vacuum application from 20 mm Hg to 52.00 mm Hg (±6.35mm Hg; p=0.005) and 45.18 mmHg (±4.34 mm Hg; p=0.005) for the 420 mbar and the 350 mbar vacuum levels, respectively. Mean intravitreal pressure increased from 20 mm Hg to 25.60 mm Hg (±9.85 mm Hg; p=0.058) and 28.10 mm Hg (±2.54 mm Hg; p=0.059) for the 420 mbar and the 350 mbar vacuum levels, respectively. Pressure values from indentation and rebound tonometry were in between intracameral and intravitreal values. Mean intracameral IOP was 18.1% higher (p=0.019) in the 420 mbar group compared with the 350 mbar group. During vacuum application of the liquid patient interface of the Femto LDV Z8 for femtosecond laser-assisted cataract surgery, IOP values were higher in the anterior chamber compared with the intravitreal pressure measurements. The higher predefined vacuum level (350 mbar vs 420 mbar) resulted in significant higher intracameral IOP. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Computer controlled scanning systems for quantitative track measurements

International Nuclear Information System (INIS)

Gold, R.; Roberts, J.H.; Preston, C.C.; Ruddy, F.H.

1982-01-01

The status of three computer cntrolled systems for quantitative track measurements is described. Two systems, an automated optical track scanner (AOTS) and an automated scanning electron microscope (ASEM) are used for scanning solid state track recorders (SSTR). The third system, the emulsion scanning processor (ESP), is an interactive system used to measure the length of proton tracks in nuclear research emulsions (NRE). Recent advances achieved with these systems are presented, with emphasis placed upon the current limitation of these systems for reactor neutron dosimetry

Ocular volume measured by CT scans

International Nuclear Information System (INIS)

Hahn, F.J.; Wei-Kom Chu

1984-01-01

Newer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia. (orig.)

Optimizing Lidar Scanning Strategies for Wind Energy Measurements (Invited)

Science.gov (United States)

Newman, J. F.; Bonin, T. A.; Klein, P.; Wharton, S.; Chilson, P. B.

2013-12-01

Environmental concerns and rising fossil fuel prices have prompted rapid development in the renewable energy sector. Wind energy, in particular, has become increasingly popular in the United States. However, the intermittency of available wind energy makes it difficult to integrate wind energy into the power grid. Thus, the expansion and successful implementation of wind energy requires accurate wind resource assessments and wind power forecasts. The actual power produced by a turbine is affected by the wind speeds and turbulence levels experienced across the turbine rotor disk. Because of the range of measurement heights required for wind power estimation, remote sensing devices (e.g., lidar) are ideally suited for these purposes. However, the volume averaging inherent in remote sensing technology produces turbulence estimates that are different from those estimated by a sonic anemometer mounted on a standard meteorological tower. In addition, most lidars intended for wind energy purposes utilize a standard Doppler beam-swinging or Velocity-Azimuth Display technique to estimate the three-dimensional wind vector. These scanning strategies are ideal for measuring mean wind speeds but are likely inadequate for measuring turbulence. In order to examine the impact of different lidar scanning strategies on turbulence measurements, a WindCube lidar, a scanning Halo lidar, and a scanning Galion lidar were deployed at the Southern Great Plains Atmospheric Radiation Measurement (ARM) site in Summer 2013. Existing instrumentation at the ARM site, including a 60-m meteorological tower and an additional scanning Halo lidar, were used in conjunction with the deployed lidars to evaluate several user-defined scanning strategies. For part of the experiment, all three scanning lidars were pointed at approximately the same point in space and a tri-Doppler analysis was completed to calculate the three-dimensional wind vector every 1 second. In another part of the experiment, one of

Scanning tip measurement for identification of point defects

Directory of Open Access Journals (Sweden)

Raineri Vito

2011-01-01

Full Text Available Abstract Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transients of the scanning tip semiconductor junction. In the Fe-deposited area, Fe-related defects dominate the surface layer in about 0.5 μm depth. These defects deteriorated the Schottky junction characteristic. Outside the Fe-deposited area, Fe-related defect concentration was identified in a thin layer near the surface. The defect transients in this area were measured both in macroscopic Schottky junctions and by scanning tip DLTS and were detected by bias modulation frequency dependence in SCM.

Holographic reconstruction of sound fields based on the acousto-optic effect

DEFF Research Database (Denmark)

Fernandez Grande, Efren; Torras Rosell, Antoni; Jacobsen, Finn

2013-01-01

Recent studies have shown that it is possible to measure a sound field using acousto-optic tomography. Theacousto-optic effect, i.e., the interaction between sound and light, can be used to measure an arbitrary soundfield by scanning it with a laser Doppler vibrometer (LDV) over an aperture; This...

Fat mass measured by DXA varies with scan velocity

DEFF Research Database (Denmark)

Black, Eva; Petersen, Liselotte; Kreutzer, Martin

2002-01-01

To study the influence of scan velocities of DXA on the measured size of fat mass, lean body mass, bone mineral content and density, and total body weight.......To study the influence of scan velocities of DXA on the measured size of fat mass, lean body mass, bone mineral content and density, and total body weight....

3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

International Nuclear Information System (INIS)

Sels, Seppe; Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve

2016-01-01

Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposed methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical

3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

Energy Technology Data Exchange (ETDEWEB)

Sels, Seppe, E-mail: Seppe.Sels@uantwerpen.be; Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve [Op3Mech Research Group, University of Antwerp, Salesianenlaan 90, 2660 Antwerp (Belgium)

2016-06-28

Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposed methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical

Laser Doppler vibrometry on rotating structures in coast-down: resonance frequencies and operational deflection shape characterization

International Nuclear Information System (INIS)

Martarelli, M; Castellini, P; Santolini, C; Tomasini, E P

2011-01-01

In rotating machinery, variations of modal parameters with rotation speed may be extremely important in particular for very light and undamped structures, such as helicopter rotors or wind turbines. The natural frequency dependence on rotation speed is conventionally measured by varying the rotor velocity and plotting natural frequencies versus speed in the so-called Campbell diagram. However, this kind of analysis does not give any information about the vibration spatial distribution i.e. the mode shape variation with the rotation speed must be investigated with dedicated procedures. In several cases it is not possible to fully control the rotating speed of the machine and only coast-down tests can be performed. Due to the reduced inertia of rotors, the coast-down process is usually an abrupt transient and therefore an experimental technique, able to determine operational deflection shapes (ODSs) in short time, with high spatial density and accuracy, appears very promising. Moreover coast-down processes are very difficult to control, causing unsteady vibrations. Hence, a very efficient approach for the rotation control and synchronous acquisition must be developed. In this paper a continuous scanning system able to measure ODSs and natural frequencies excited during rotor coast-down is shown. The method is based on a laser Doppler vibrometer (LDV) whose laser beam is driven to scan continuously over the rotor surface, in order to measure the ODS, and to follow the rotation of the rotor itself even in coast-down. With a single measurement the ODSs can be recovered from the LDV output time history in short time and with huge data saving. This technique has been tested on a laboratory test bench, i.e. a rotating two-blade fan, and compared with a series of non-contact approaches based on LDV: - traditional experimental modal analysis (EMA) results obtained under non-rotating conditions by measuring on a sequence of points on the blade surface excited by an impact

Measurement Axis Searching Model for Terrestrial Laser Scans Registration

Directory of Open Access Journals (Sweden)

Shaoxing Hu

2016-01-01

Full Text Available Nowadays, terrestrial Lidar scans can cover rather a large area; the point densities are strongly varied because of the line-of-sight measurement principle in potential overlaps with scans taken from different viewpoints. Most of the traditional methods focus on registration algorithm and ignore searching model. Sometimes the traditional methods are directly used to align two point clouds; a large critically unsolved problem of the large biases will be created in areas distant from the overlaps while the local overlaps are often aligned well. So a novel measurement axis searching model (MASM has been proposed in this paper. The method includes four steps: (1 the principal axis fitting, (2 the measurement axis generation, (3 low-high-precision search, and (4 result generation. The principal axis gives an orientation to the point cloud; the search scope is limited by the measurement axis. The point cloud orientation can be adjusted gradually until the achievement of the global optimum using low- and high-precision search. We perform some experiments with simulated point clouds and real terrestrial laser scans. The results of simulated point clouds have shown the processing steps of our method, and the results of real terrestrial laser scans have shown the sensitivity of the approach with respect to the indoor and outdoor scenes.

Distance measurement using frequency scanning interferometry with mode-hoped laser

Science.gov (United States)

Medhat, M.; Sobee, M.; Hussein, H. M.; Terra, O.

2016-06-01

In this paper, frequency scanning interferometry is implemented to measure distances up to 5 m absolutely. The setup consists of a Michelson interferometer, an external cavity tunable diode laser, and an ultra-low expansion (ULE) Fabry-Pérot (FP) cavity to measure the frequency scanning range. The distance is measured by acquiring simultaneously the interference fringes from, the Michelson and the FP interferometers, while scanning the laser frequency. An online fringe processing technique is developed to calculate the distance from the fringe ratio while removing the parts result from the laser mode-hops without significantly affecting the measurement accuracy. This fringe processing method enables accurate distance measurements up to 5 m with measurements repeatability ±3.9×10-6 L. An accurate translation stage is used to find the FP cavity free-spectral-range and therefore allow accurate measurement. Finally, the setup is applied for the short distance calibration of a laser distance meter (LDM).

Quantitative measurement of ventricular dilatation on CT scan

International Nuclear Information System (INIS)

Okita, Naoshi; Mochizuki, Hiroshi; Takase, Sadao

1985-01-01

Cerebral atrophy might be judged from the ventricular dilatation with some indices, calculated from various ventricular width. But, there is no general agreement on what index is the most reliable. In this paper, we attempted to establish the index, easy to measure and most reliable. Our method is as follow. 1) We carried out the CT scan (EMI 1010) on 89 neurologically intact patients. Scans were parallel to orbito-meatal line (OML), and were 10 mm in thickness. On CT scan films, various width, area of anterior horns and area of bodies of lateral ventricles were measured. Measurement about the anterior horns of lateral ventricles were carried out on image the most clearly showed the foramen of Monro. And measurements about the bodies of lateral ventricles were on image, 20 mm above the image of anterior horn. Correlations of various width and areas were calculated. Then we proposed new indices with high correlations (over 0.9) with ventricular area; Anterior horn CVI (Cerebro-Ventricular Index) and Body CVI. 2) Patients with myotonic dystrophy show cerebral atrophy. We carried out the CT scan (GECT/T 8800) on 17 myotonic dystrophy patients and 30 controls. Between the two groups, age and sex were almost matched. In the two groups, we calculated our new indices as well as various indices which have been reported; Huckman number, Bifrontal CVI, Bicaudal CVI, Anterior horn index, Hirajima's index, and Cella-media index. The data were analyzed statistically. The ventricular dilatation of myotonic dystrophy patients is more definite with Anterior horn CVI, Bicaudal CVI and Body CVI (p<0.01). These indices have higher correlations with the ventricular area (about 0.9). (J.P.N.)

Multiple-beam LDV system for buried landmine detection

Science.gov (United States)

Lal, Amit K.; Zhang, Hansheng; Aranchuk, Vyacheslav; Hurtado, Ernesto; Hess, Cecil F.; Burgett, Richard D.; Sabatier, James M.

2003-09-01

This paper discusses the performance and experimental results of a multiple beam laser Doppler vibrometer designed to locate buried landmines with the laser-acoustic technique. The device increases the speed of landmine detection by simultaneously probing 16 positions on the ground over a span of 1 meter, and measuring the ground velocity at each of these positions. Experimental results are presented from controlled laboratory experiments as well as from landmine test lanes at the University of Mississippi. In the mine lanes, the multiple beam system is raised to a height of 2.5 meters with a forklift, with the 16 beams spread over a 1 meter line along the mine lane. A motor system then allows the 16 beams to be translated across the mine lane, enabling the system to scan a 1 x 1 meter area in a much shorter time than with previous scanning techniques. The effects of experimental parameters such as platform motion, angle of incidence, speckle dropout, and system depth-of-field will be presented and discussed.

Measurement of turbulent flow fields in a agitated vessel with four baffles by laser-doppler velocimetry. Analysis with periodic averaged velocity profiles; Baffle tsuki heiento kakuhan sonai nagare no LDV ni yoru keisoku. Shuki heikin sokudo bunpu ni yoru kaiseki

Energy Technology Data Exchange (ETDEWEB)

Suzukawa, K [Ube Industries, Ltd., Tokyo (Japan); Hashimoto, T; Osaka, H [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering

1997-11-25

The 3-D flow field relative to a rotating paddle blade is acquired by synchronizing LDV measurements with the output of a shaft-mounted encoder. This makes it possible to capture the impeller stream velocity field, including the details of the discharge flow region behind the blades. Mean velocities ensemble-averaged between a specific impeller blade pair (over 90deg) show the extent of periodicity and the passage and structure of the discharge flow region. Pumping capacities are determined at both sides of impeller and tip of impeller, and it is shown that the radial jet is a consequence of fluid entrainment into the discharge flow region. Mean velocities taken in a rotating frame of reference reveal a significant periodic variation near the impeller than those taken in a fixed frame. 13 refs., 12 figs., 1 tab.

Gwyscan: a library to support non-equidistant scanning probe microscope measurements

International Nuclear Information System (INIS)

Klapetek, Petr; Grolich, Petr; Valtr, Miroslav; Yacoot, Andrew; Nečas, David

2017-01-01

We present a software library and related methodology for enabling easy integration of adaptive step (non-equidistant) scanning techniques into metrological scanning probe microscopes or scanning probe microscopes where individual x , y position data are recorded during measurements. Scanning with adaptive steps can reduce the amount of data collected in SPM measurements thereby leading to faster data acquisition, a smaller amount of data collection required for a specific analytical task and less sensitivity to mechanical and thermal drift. Implementation of adaptive scanning routines into a custom built microscope is not normally an easy task: regular data are much easier to handle for previewing (e.g. levelling) and storage. We present an environment to make implementation of adaptive scanning easier for an instrument developer, specifically taking into account data acquisition approaches that are used in high accuracy microscopes as those developed by National Metrology Institutes. This includes a library with algorithms written in C and LabVIEW for handling data storage, regular mesh preview generation and planning the scan path on basis of different assumptions. A set of modules for Gwyddion open source software for handling these data and for their further analysis is presented. Using this combination of data acquisition and processing tools one can implement adaptive scanning in a relatively easy way into an instrument that was previously measuring on a regular grid. The performance of the presented approach is shown and general non-equidistant data processing steps are discussed. (paper)

Gwyscan: a library to support non-equidistant scanning probe microscope measurements

Science.gov (United States)

Klapetek, Petr; Yacoot, Andrew; Grolich, Petr; Valtr, Miroslav; Nečas, David

2017-03-01

We present a software library and related methodology for enabling easy integration of adaptive step (non-equidistant) scanning techniques into metrological scanning probe microscopes or scanning probe microscopes where individual x, y position data are recorded during measurements. Scanning with adaptive steps can reduce the amount of data collected in SPM measurements thereby leading to faster data acquisition, a smaller amount of data collection required for a specific analytical task and less sensitivity to mechanical and thermal drift. Implementation of adaptive scanning routines into a custom built microscope is not normally an easy task: regular data are much easier to handle for previewing (e.g. levelling) and storage. We present an environment to make implementation of adaptive scanning easier for an instrument developer, specifically taking into account data acquisition approaches that are used in high accuracy microscopes as those developed by National Metrology Institutes. This includes a library with algorithms written in C and LabVIEW for handling data storage, regular mesh preview generation and planning the scan path on basis of different assumptions. A set of modules for Gwyddion open source software for handling these data and for their further analysis is presented. Using this combination of data acquisition and processing tools one can implement adaptive scanning in a relatively easy way into an instrument that was previously measuring on a regular grid. The performance of the presented approach is shown and general non-equidistant data processing steps are discussed.

Double phi-Step theta-Scanning Technique for Spherical Near-Field Antenna Measurements

DEFF Research Database (Denmark)

Laitinen, Tommi

2008-01-01

Probe-corrected spherical near-field antenna measurements with an arbitrary probe set certain requirements on an applicable scanning technique. The computational complexity of the general high-order probe correction technique for an arbitrary probe, that is based on the Phi scanning, is O(N4...... a specific double Phi-step thetas scanning technique for spherical near-field antenna measurements. This technique not only constitutes an alternative spherical scanning technique, but it also enables formulating an associated probe correction technique for arbitrary probes with the computational complexity...

Pressure drop ana velocity measurements in KMRR fuel rod bundles

International Nuclear Information System (INIS)

Yagn, Sun Kyu; Chung, Heung June; Chung, Chang Whan; Chun, Se Young; Song, Chul Wha; Won, Soon Yeun; Chung, Moon Ki

1990-01-01

The detailed hydraulic characteristic measurements in subchannels of longitudinally finned rod bundles using one-component LDV(Laser Doppler Velocimeter) were performed. Time mean axial velocity, turbulent intensity, and turbulent micro scales, such as time auto-correlation, Eulerian integral and micro scale, Kolmogorov length and time scale, and Taylor micro length scale were measured. The signals from LDV are inherently more or less discontinuous. The spectra of signals having such intermittent defects can be obtained by the fast Fourier transformation (FFT) of the auto-correlation function. The turbulent crossflow mixing rate between neighboring subchannels and dominant frequencies were evaluated from the measured data. Pressure drop data were obtained for the typical 36-element and 18-element fuel rod bundles fabricated by the design requirement of KMRR fuel and for other type of fuels assembled with 6-fin rods to investigate the fin effects on the pressure drop characteristics

Development of high-power laser technology. Fabrication of a dye cell of the high power dye laser and development of the measurement technology of the fluid velocities in a dye cell

Energy Technology Data Exchange (ETDEWEB)

Jo, Jae Heung; Chang, Soo; Lim, Kwon; Kim, Jee Teak; Choi, Wan Hae [Hannam University, Taejon (Korea, Republic of)

1995-08-01

The computer simulation code for the simulation of the steady-state flow in a dye cell is developed by using the finite element method. The situation of the fluid flow is measured by the diode laser LDV system and compared with results of the computer simulation. The small size Fiber-Optic LDV with a directional coupler is designed and fabricated for the real time measurement of fluid velocities in a dye cell. (author). 13 refs.

Organ dose evaluation for CT scans based on in-phantom measurements

International Nuclear Information System (INIS)

Liu Haikuan; Zhuo Weihai; Chen Bo; Yi Yanling; Li Dehong

2009-01-01

Objective: To explore the organ doses and their distributions in different projections of CT scans. Methods: The CT values were measured and the linear absorption coefficients were derived for the main organs of the anthropomorphic phantom to compare with the normal values of human beings. The radiophotoluminescent glass dosimeters were set into various tissues or organs of the phantom for mimic measurements of the organ doses undergoing the head, chest, abdomen and pelvis CT scans, respectively. Results: The tissue equivalence of the phantom used in this study was good. The brain had the largest organ dose undergoing the head CT scan. The organ doses in thyroid, breast, lung and oesophagus were relatively large in performing the chest CT scan, while the liver, stomach, colon and lung had relatively hrge organ doses in abdomen CT practice. The doses in bone surface and colon exceeded by 50 mGy in a single pelvis CT scan. Conclusions: The organ doses and their distributions largely vary with different projections of CT scans. The organ doses of colon, bone marrow,gonads and bladder are fairly large in performing pelvis CT scan, which should be paid attention in the practice. (authors)

Measuring the plutonium distribution in fuel elements by the gamma scanning method

International Nuclear Information System (INIS)

Gorobets, A.K.; Leshchenko, Yu.I.; Semenov, A.L.

1982-01-01

An on-line system designed for measuring Pu distribution in the length of fresh fuel elements with vibrocompacted UO 2 -PuO 2 fuel rods by the γ-scanning method is described. An algorithm for measurement result processing and the procedure of determination of calibration parameters necessary for the valid signal separat.ion by means of a two-channel analyzer and for evaluation of the self-absorption effect are considered. The device scanning unit consists of two NaI(Tl) detectors simultaneously detecting γ-radiation from the opposite sides of a measured fuel rod section. The cesium source with Esub(γ)=660 keV is used for fuel scanning. On the base of the analysis of the results obtained when studying the BOR-60 experimental fuel elements with fuel rods of 400 mm long by means of the described device clusion is made that fuel element scanning during 20 min (scanning step is 4 mm, measuring time at each step is 10 s) makes it possible to determine Pu distribution with the error less than +-4% at the confidence probability of 0.68

On-line pressure measurement using scanning systems

International Nuclear Information System (INIS)

Morss, A.G.; Watson, A.P.

1978-08-01

Data collection methods can be improved significantly by using pressure scanning systems in conjunction with transducers for the measurement of pressure distribution in fluid flow rigs. However, the response of pressure transducers to the slight random pressure fluctuations that occur in practice can cause some measurement problems, especially for accurate work. The nature of these pressure fluctuations is examined and suitable analysis techniques are recommended. Results obtained using these techniques are presented. It is concluded that by using the correct techniques pressure transducer systems can be used to measure pressure distributions accurately and are sufficiently sensitive to measure very small systematic effects with great precision. (author)

Investigation of turbulence measurements with a continuous wave, conically scanning LiDAR

DEFF Research Database (Denmark)

Wagner, Rozenn; Mikkelsen, Torben; Courtney, Michael

averaging is done in two steps: 1) the weighted averaging of the wind speed in the probe volume of the laser beam; 2) the averaging of the wind speeds occurring on the circular path described by the conically scanning lidar. Therefore the standard deviation measured by a lidar resolves only the turbulence...... of a continuous wave, conically scanning Zephir lidar. First, the wind speed standard deviation measured by such a lidar gives on average 80% of the standard deviation measured by a cup anemometer. This difference is due to the spatial averaging inherently made by a cw conically scanning lidar. The spatial...

Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

2015-06-22

An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

Alternative Measuring Approaches in Gamma Scanning on Spent Nuclear Fuel

Energy Technology Data Exchange (ETDEWEB)

Sihm Kvenangen, Karen

2007-06-15

In the future, the demand for energy is predicted to grow and more countries plan to utilize nuclear energy as their source of electric energy. This gives rise to many important issues connected to nuclear energy, such as finding methods that can verify that the spent nuclear fuel has been handled safely and used in ordinary power producing cycles as stated by the operators. Gamma ray spectroscopy is one method used for identification and verification of spent nuclear fuel. In the specific gamma ray spectroscopy method called gamma scanning the gamma radiation from the fission products Cs-137, Cs-134 and Eu-154 are measured in a spent fuel assembly. From the results, conclusions can be drawn about the fuels characteristics. This degree project examines the possibilities of using alternative measuring approaches when using the gamma scanning method. The focus is on examining how to increase the quality of the measured data. How to decrease the measuring time as compared with the present measuring strategy, has also been investigated. The main part of the study comprises computer simulations of gamma scanning measurements. The simulations have been validated with actual measurements on spent nuclear fuel at the central interim storage, Clab. The results show that concerning the quality of the measuring data the conventional strategy is preferable, but with other starting positions and with a more optimized equipment. When focusing on the time aspect, the helical measuring strategy can be an option, but this needs further investigation.

Alternative Measuring Approaches in Gamma Scanning on Spent Nuclear Fuel

International Nuclear Information System (INIS)

Sihm Kvenangen, Karen

2007-06-01

In the future, the demand for energy is predicted to grow and more countries plan to utilize nuclear energy as their source of electric energy. This gives rise to many important issues connected to nuclear energy, such as finding methods that can verify that the spent nuclear fuel has been handled safely and used in ordinary power producing cycles as stated by the operators. Gamma ray spectroscopy is one method used for identification and verification of spent nuclear fuel. In the specific gamma ray spectroscopy method called gamma scanning the gamma radiation from the fission products Cs-137, Cs-134 and Eu-154 are measured in a spent fuel assembly. From the results, conclusions can be drawn about the fuels characteristics. This degree project examines the possibilities of using alternative measuring approaches when using the gamma scanning method. The focus is on examining how to increase the quality of the measured data. How to decrease the measuring time as compared with the present measuring strategy, has also been investigated. The main part of the study comprises computer simulations of gamma scanning measurements. The simulations have been validated with actual measurements on spent nuclear fuel at the central interim storage, Clab. The results show that concerning the quality of the measuring data the conventional strategy is preferable, but with other starting positions and with a more optimized equipment. When focusing on the time aspect, the helical measuring strategy can be an option, but this needs further investigation

Measurement uncertainty budget of an interferometric flow velocity sensor

Science.gov (United States)

Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

2017-06-01

Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

Multi-year remote-sensing measurements of gasoline light-duty vehicle emissions on a freeway ramp

International Nuclear Information System (INIS)

Sjoedin, A.; Andreasson, K.

2000-01-01

On-road optical remote-sensing measurements of gasoline light-duty vehicle (LDV) emissions - CO, HC, NO - were conducted on a freeway ramp in Gothenburg, Sweden, in 1991, 1995 and 1998. Based on almost 30,000 emission measurements, the results show that both catalyst cars and non-catalyst cars emissions deteriorate over time, but also that the emission performance of new TWC-cars has improved significantly in recent years. Furthermore, it was found that fleet age rather than model year determines the rate of emission deterioration for TWC-cars for both CO and NO. The study demonstrates that remote sensing may constitute a powerful tool to evaluate real-world LDV emissions; however, daily field calibration procedures need to be developed in order to assure that the evolution in fleet average emissions can be accurately measured. (author)

Monostatic coaxial 1.5 μm laser Doppler velocimeter using a scanning Fabry-Perot interferometer

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2013-01-01

on heterodyne detection, our sFPI-LDV has the advantages of having large remote sensing range not limited by laser coherence, high velocity dynamic range not limited by detector bandwidth and inherent sign discrimination of Doppler shift. The more optically efficient coaxial arrangement where transmitter...... achieves ~40 dB reduction in strength of unwanted reflections (i.e. leakage) while maintaining high optical efficiency. Experiments with a solid target demonstrate the performance of the sFPI-LDV system with high sensitivity down to pW level at present update rates up to 10 Hz....

Measurement needs guided by synthetic radar scans in high-resolution model output

Science.gov (United States)

Varble, A.; Nesbitt, S. W.; Borque, P.

2017-12-01

Microphysical and dynamical process interactions within deep convective clouds are not well understood, partly because measurement strategies often focus on statistics of cloud state rather than cloud processes. While processes cannot be directly measured, they can be inferred with sufficiently frequent and detailed scanning radar measurements focused on the life cycleof individual cloud regions. This is a primary goal of the 2018-19 DOE ARM Cloud, Aerosol, and Complex Terrain Interactions (CACTI) and NSF Remote sensing of Electrification, Lightning, And Mesoscale/microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaigns in central Argentina, where orographic deep convective initiation is frequent with some high-impact systems growing into the tallest and largest in the world. An array of fixed and mobile scanning multi-wavelength dual-polarization radars will be coupled with surface observations, sounding systems, multi-wavelength vertical profilers, and aircraft in situ measurements to characterize convective cloud life cycles and their relationship with environmental conditions. While detailed cloud processes are an observational target, the radar scan patterns that are most ideal for observing them are unclear. They depend on the locations and scales of key microphysical and dynamical processes operating within the cloud. High-resolution simulations of clouds, while imperfect, can provide information on these locations and scales that guide radar measurement needs. Radar locations are set in the model domain based on planned experiment locations, and simulatedorographic deep convective initiation and upscale growth are sampled using a number of different scans involving RHIs or PPIs with predefined elevation and azimuthal angles that approximately conform with radar range and beam width specifications. Each full scan pattern is applied to output atsingle model time steps with time step intervals that depend on the length of time

The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

Science.gov (United States)

Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

2015-10-01

Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

Features of the non-contact carotid pressure waveform: Cardiac and vascular dynamics during rebreathing

Science.gov (United States)

Casaccia, S.; Sirevaag, E. J.; Richter, E. J.; O'Sullivan, J. A.; Scalise, L.; Rohrbaugh, J. W.

2016-10-01

This report amplifies and extends prior descriptions of the use of laser Doppler vibrometry (LDV) as a method for assessing cardiovascular activity, on a non-contact basis. A rebreathing task (n = 35 healthy individuals) was used to elicit multiple effects associated with changes in autonomic drive as well as blood gases including hypercapnia. The LDV pulse was obtained from two sites overlying the carotid artery, separated by 40 mm. A robust pulse signal was obtained from both sites, in accord with the well-described changes in carotid diameter over the blood pressure cycle. Emphasis was placed on extracting timing measures from the LDV pulse, which could serve as surrogate measures of pulse wave velocity (PWV) and the associated arterial stiffness. For validation purposes, a standard measure of pulse transit time (PTT) to the radial artery was obtained using a tonometric sensor. Two key measures of timing were extracted from the LDV pulse. One involved the transit time along the 40 mm distance separating the two LDV measurement sites. A second measure involved the timing of a late feature of the LDV pulse contour, which was interpreted as reflection wave latency and thus a measure of round-trip travel time. Both LDV measures agreed with the conventional PTT measure, in disclosing increased PWV during periods of active rebreathing. These results thus provide additional evidence that measures based on the non-contact LDV technique might provide surrogate measures for those obtained using conventional, more obtrusive assessment methods that require attached sensors.

Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires

International Nuclear Information System (INIS)

Zubkov, Evgeniy

2013-01-01

In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

PEPR and other CRT scanning and measuring devices

Energy Technology Data Exchange (ETDEWEB)

Pless, Irwin A. (Massachusetts Institute of Technology, Cambridge, MA 02139 (United States))

1994-07-01

This talk concentrates on the brief history of the PEPR (Precision Encoding and Pattern Recognition) scanning and measuring device.I restrict this reminiscence to just a short history of PEPR, the other various CRT scanners, a short summary of the capabilities of this scanner and some fond memories. ((orig.))

PEPR and other CRT scanning and measuring devices

International Nuclear Information System (INIS)

Pless, Irwin A.

1994-01-01

This talk concentrates on the brief history of the PEPR (Precision Encoding and Pattern Recognition) scanning and measuring device.I restrict this reminiscence to just a short history of PEPR, the other various CRT scanners, a short summary of the capabilities of this scanner and some fond memories. ((orig.))

Evaluation of the flow-accelerated corrosion downstream of an orifice. 1. Measurements and numerical analysis of flow field

International Nuclear Information System (INIS)

Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

2008-01-01

In this study, in order to evaluate the effects of flow field on corrosion rate due to flow accelerated corrosion (FAC), an orifice flow was measured and calculated. The diameter of pipe is 50 mm and that of the orifice is 24.3 mm, and flow velocity in a water loop was set at 2.41 m/s. Flow field was measured by laser Doppler velocimetry (LDV) and particle image velocimetry (PIV), and compared with a calculation for the same flow conditions. Measurements of wall shear stress downstream of the orifice was also planed. The calculated velocity distribution of standard k-□ agreed qualitatively with PIV data and quantitatively with LDV data. Instantaneous flow field measured by PIV showed vortices around the jet from the orifice and some of them reached near the pipe wall. (author)

Research on Method of Photoelectric Measurement for Tilt Angle of Scanning Mirror of Infrared Earth Sensor

Energy Technology Data Exchange (ETDEWEB)

Xu, X P; Zhang, G Y; Zhang, N; Wang, L Y [Changchun University of Science and Technology, 130022, Changchun (China)

2006-10-15

Tilt angle of scanning mirror is one of the important qualifications of performance measurement on the earth surface for swing scanning mode infrared the earth sensor. In order to settle the problem of measuring the tilt angle of scanning mirror in dynamic, real-time and non-contact, based on laser inspecting technology and CCD probing technology, a method of laser dynamical measurement for tilt angle of scanning mirror of the infrared earth sensor is presented. The measurement system developed in this paper can accomplish the dynamic and static laser non-contact measurement for the parameters of scanning mirror such as tilt angle, swing frequency, etc. In this paper the composition and overall structure of system are introduced. Emphasis on analyzing and discussing the theory of dynamically measuring tilt angle of scanning mirror, the problems of data processing and error correction are settled by established mathematic model of system. The accuracy of measurement system is verified by experiment, the results indicated that measurement range of system for tilt angle is 0{approx}{+-}12{sup 0}, accuracy of dynamic and static measurement is less than {+-}0.05{sup 0}, this method of dynamically measuring tilt angle is suitable.

A consideration of a measuring point of ventricular dilatation on CT scanning

International Nuclear Information System (INIS)

Kuno, Koichi; Miyake, Kazuo

1980-01-01

Ventricular dilatation has been judged by pneumo-ventricurography, pneumo-encepharography and carotid angiography (CAG), though all these procedures are very uncomfortable for patients. On the other hand, the CT scan is very easy as a follow-up study of ventricular dilatation for a weak patient. We carried out the CT scan (Hitachi CT-H 250 Scanner, NaI detector) and CAG on 84 cases. The ventricular dilatation was judged by the degree of outstretch of the strio-thalamic vein on an AP view of the phrebogram, classified into 3 types. For all three types classified by the phrebogram, we studied various measuring points of the ventricle on the CT scan. The portions measured on the CT scan were: (1) the frontal cerebro-ventricular index (F-CVI), (2) the bicaudate cerebro-ventricular index (Bicaud-CVI), and (3) the maximum Monro's cerebro-ventricular index (M-CVI), the width of the frontal horn, and the thickness of the ventricular body. The following results were obtained: (1) In measuring the ventricular size on the CT scan, the most interrelated point with the ventricular dilatation is the M-CVI - the ratio of the largest width of the body through the Monro foramen to the width of the brain. In this case, however, the width of the frontal horn and of the body should also be considered. (2) Voltage and electric current changed the EMI-number, but did not alter the measuring value. In this case, the width and the level should be kept constant. (3) The group with the marked ventricular dilatation has a larger value of the CT scan than its value of GAG. (4) The normal value of the M-CVI is 24 +- 3%, moreover, the width of the frontal horn is less than 10 mm, and the thickness of the ventricular body is less than 17 mm. (author)

A few nascent methods for measuring mechanical properties of the biological cell.

Energy Technology Data Exchange (ETDEWEB)

Thayer, Gayle Echo; de Boer, Maarten Pieter; Corvalan, Carlos (Purdue University, West Lafayette, IN); Corwin, Alex David; Campanella, Osvaldo H. (Purdue University, West Lafayette, IN); Nivens, David (Purdue University, West Lafayette, IN); Werely, Steven (Purdue University, West Lafayette, IN); Sumali, Anton Hartono; Koch, Steven John

2006-01-01

This report summarizes a survey of several new methods for obtaining mechanical and rheological properties of single biological cells, in particular: (1) The use of laser Doppler vibrometry (LDV) to measure the natural vibrations of certain cells. (2) The development of a novel micro-electro-mechanical system (MEMS) for obtaining high-resolution force-displacement curves. (3) The use of the atomic force microscope (AFM) for cell imaging. (4) The adaptation of a novel squeezing-flow technique to micro-scale measurement. The LDV technique was used to investigate the recent finding reported by others that the membranes of certain biological cells vibrate naturally, and that the vibration can be detected clearly with recent instrumentation. The LDV has been reported to detect motions of certain biological cells indirectly through the motion of a probe. In this project, trials on Saccharomyces cerevisiae tested and rejected the hypothesis that the LDV could measure vibrations of the cell membranes directly. The MEMS investigated in the second technique is a polysilicon surface-micromachined force sensor that is able to measure forces to a few pN in both air and water. The simple device consists of compliant springs with force constants as low as 0.3 milliN/m and Moire patterns for nanometer-scale optical displacement measurement. Fields from an electromagnet created forces on magnetic micro beads glued to the force sensors. These forces were measured and agreed well with finite element prediction. It was demonstrated that the force sensor was fully functional when immersed in aqueous buffer. These results show the force sensors can be useful for calibrating magnetic forces on magnetic beads and also for direct measurement of biophysical forces on-chip. The use of atomic force microscopy (AFM) for profiling the geometry of red blood cells was the third technique investigated here. An important finding was that the method commonly used for attaching the cells to a

Analysis on the dynamic error for optoelectronic scanning coordinate measurement network

Science.gov (United States)

Shi, Shendong; Yang, Linghui; Lin, Jiarui; Guo, Siyang; Ren, Yongjie

2018-01-01

Large-scale dynamic three-dimension coordinate measurement technique is eagerly demanded in equipment manufacturing. Noted for advantages of high accuracy, scale expandability and multitask parallel measurement, optoelectronic scanning measurement network has got close attention. It is widely used in large components jointing, spacecraft rendezvous and docking simulation, digital shipbuilding and automated guided vehicle navigation. At present, most research about optoelectronic scanning measurement network is focused on static measurement capacity and research about dynamic accuracy is insufficient. Limited by the measurement principle, the dynamic error is non-negligible and restricts the application. The workshop measurement and positioning system is a representative which can realize dynamic measurement function in theory. In this paper we conduct deep research on dynamic error resources and divide them two parts: phase error and synchronization error. Dynamic error model is constructed. Based on the theory above, simulation about dynamic error is carried out. Dynamic error is quantized and the rule of volatility and periodicity has been found. Dynamic error characteristics are shown in detail. The research result lays foundation for further accuracy improvement.

Evaluation of three lidar scanning strategies for turbulence measurements

DEFF Research Database (Denmark)

Newman, Jennifer F.; Klein, Petra M.; Wharton, Sonia

2016-01-01

Several errors occur when a traditional Doppler beam swinging (DBS) or velocity-azimuth display (VAD) strategy is used to measure turbulence with a lidar. To mitigate some of these errors, a scanning strategy was recently developed which employs six beam positions to independently estimate the u,...

Measuring the human psychophysiological conditions without contact

Science.gov (United States)

Scalise, L.; Casacanditella, L.; Cosoli, G.

2017-08-01

Heart Rate Variability, HRV, studies the variations of cardiac rhythm caused by the autonomic regulation. HRV analysis can be applied to the study of the effects of mental or physical stressors on the psychophysiological conditions. The present work is a pilot study performed on a 23-year-old healthy subject. The measurement of HRV was performed by means of two sensors, that is an electrocardiograph and a Laser Doppler Vibrometer, which is a non-contact device able to detect the skin vibrations related to the cardiac activity. The present study aims to evaluate the effects of a physical task on HRV parameters (in both time and frequency domain), and consequently on the autonomic regulation, and the capability of Laser Doppler Vibrometry in correctly detecting the effects of stress on the Heart Variability. The results show a significant reduction of HRV parameters caused by the execution of the physical task (i.e. variations of 25-40% for parameters in time domain, also higher in frequency domain); this is consistent with the fact that stress causes a reduced capability of the organism in varying the Heart Rate (and, consequently, a limited HRV). LDV was able to correctly detect this phenomenon in the time domain, while the parameters in the frequency domain show significant deviations with respect to the gold standard technique (i.e. ECG). This may be due to the movement artefacts that have consistently modified the shape of the vibration signal measured by means of LDV, after having performed the physical task. In the future, in order to avoid this drawback, the LDV technique could be used to evaluate the effects of a mental task on HRV signals (i.e. the evaluation of mental stress).

Measurement of mesothelioma on thoracic CT scans: A comparison of manual and computer-assisted techniques

International Nuclear Information System (INIS)

Armato, Samuel G. III; Oxnard, Geoffrey R.; MacMahon, Heber; Vogelzang, Nicholas J.; Kindler, Hedy L.; Kocherginsky, Masha; Starkey, Adam

2004-01-01

Our purpose in this study was to evaluate the variability of manual mesothelioma tumor thickness measurements in computed tomography (CT) scans and to assess the relative performance of six computerized measurement algorithms. The CT scans of 22 patients with malignant pleural mesothelioma were collected. In each scan, an initial observer identified up to three sites in each of three CT sections at which tumor thickness measurements were to be made. At each site, five observers manually measured tumor thickness through a computer interface. Three observers repeated these measurements during three separate sessions. Inter- and intra-observer variability in the manual measurement of tumor thickness was assessed. Six automated measurement algorithms were developed based on the geometric relationship between a specified measurement site and the automatically extracted lung regions. Computer-generated measurements were compared with manual measurements. The tumor thickness measurements of different observers were highly correlated (r≥0.99); however, the 95% limits of agreement for relative inter-observer difference spanned a range of 30%. Tumor thickness measurements generated by the computer algorithms also correlated highly with the average of observer measurements (r≥0.93). We have developed computerized techniques for the measurement of mesothelioma tumor thickness in CT scans. These techniques achieved varying levels of agreement with measurements made by human observers

Volumetric measurement of the maxillary sinus by coronal CT scan

International Nuclear Information System (INIS)

Ikeda, Atsuko

1996-01-01

The volume of the maxillary sinus was estimated by coronal CT scan. The purpose of this study was to compare the estimated volume of the normal maxillary sinus with that of the inflamed maxillary sinus. Patients were classified following evaluation by CT scan of the paranasal sinuses into 3 categories. Group A (n=12): Patients suffered from headache, facial pain and epistaxis, but CT scans of their nasal cavity and paranasal sinus were within normal limits without inflammatory change. Group B (n=69): Patients with bilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory changes in both maxillary sinuses. All of the patients in this group underwent sinus surgery after coronal CT scans. Group C (n=14): Patients with unilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory change in unilateral maxillary sinuses. CT scans of these patients were measured by Plannimeter to take the area of each image of the maxillary sinus. Consecutively imaged areas were summated by integral calculus to obtain an estimate of the sinus volume. The mean maxillary sinus volume in the affected sinuses was significantly smaller than those in the contralateral normal sinuses (p<0.05, Wilcoxon-test). The various volumes of the maxillary sinuses and the developmental cause were discussed. Comparison of groups A with B suggested three distinct patterns; the maxillary sinus volume has decreased due to inflammatory changes in the bone. The small sinuses have a tendency to develop chronic inflammatory change. The aeration in the maxillary sinus may be decreased when anatomic variations that may obstruct the ethmoid infundibulum exist. (K.H.)

Volumetric measurement of the maxillary sinus by coronal CT scan

Energy Technology Data Exchange (ETDEWEB)

Ikeda, Atsuko [Tokyo Medical and Dental Univ. (Japan). School of Medicine

1996-08-01

The volume of the maxillary sinus was estimated by coronal CT scan. The purpose of this study was to compare the estimated volume of the normal maxillary sinus with that of the inflamed maxillary sinus. Patients were classified following evaluation by CT scan of the paranasal sinuses into 3 categories. Group A (n=12): Patients suffered from headache, facial pain and epistaxis, but CT scans of their nasal cavity and paranasal sinus were within normal limits without inflammatory change. Group B (n=69): Patients with bilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory changes in both maxillary sinuses. All of the patients in this group underwent sinus surgery after coronal CT scans. Group C (n=14): Patients with unilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory change in unilateral maxillary sinuses. CT scans of these patients were measured by Plannimeter to take the area of each image of the maxillary sinus. Consecutively imaged areas were summated by integral calculus to obtain an estimate of the sinus volume. The mean maxillary sinus volume in the affected sinuses was significantly smaller than those in the contralateral normal sinuses (p<0.05, Wilcoxon-test). The various volumes of the maxillary sinuses and the developmental cause were discussed. Comparison of groups A with B suggested three distinct patterns; the maxillary sinus volume has decreased due to inflammatory changes in the bone. The small sinuses have a tendency to develop chronic inflammatory change. The aeration in the maxillary sinus may be decreased when anatomic variations that may obstruct the ethmoid infundibulum exist. (K.H.)

Evaluation of the Repeatability and the Reproducibility of AL-Scan Measurements Obtained by Residents

Directory of Open Access Journals (Sweden)

Mehmet Kola

2014-01-01

Full Text Available Purpose. To assess the repeatability and reproducibility of ocular biometry and intraocular lens (IOL power measurements obtained by ophthalmology residents using an AL-Scan device, a novel optical biometer. Methods. Two ophthalmology residents were instructed regarding the AL-Scan device. Both performed ocular biometry and IOL power measurements using AL-Scan, three times on each of 128 eyes, independently of one another. Corneal keratometry readings, horizontal iris width, central corneal thickness, anterior chamber depth, pupil size, and axial length values measured by both residents were recorded together with IOL power values calculated on the basis of four different IOL calculation formulas (SRK/T, Holladay, and HofferQ. Repeatability and reproducibility of the measurements obtained were analyzed using the intraclass correlation coefficient (ICC. Results. Repeatability (ICC, 0.872-0.999 for resident 1 versus 0.905-0.999 for resident 2 and reproducibility (ICC, 0.916-0.999 were high for all biometric measurements. Repeatability (ICC, 0.981-0.983 for resident 1 versus 0.995-0.996 for resident 2 and reproducibility were also high for all IOL power measurements (ICC, 0.996 for all. Conclusions. The AL-Scan device exhibits good repeatability and reproducibility in all biometric measurements and IOL power calculations, independent of the operator concerned.

Quantitative measurement of piezoelectric coefficient of thin film using a scanning evanescent microwave microscope.

Science.gov (United States)

Zhao, Zhenli; Luo, Zhenlin; Liu, Chihui; Wu, Wenbin; Gao, Chen; Lu, Yalin

2008-06-01

This article describes a new approach to quantitatively measure the piezoelectric coefficients of thin films at the microscopic level using a scanning evanescent microwave microscope. This technique can resolve 10 pm deformation caused by the piezoelectric effect and has the advantages of high scanning speed, large scanning area, submicron spatial resolution, and a simultaneous accessibility to many other related properties. Results from the test measurements on the longitudinal piezoelectric coefficient of PZT thin film agree well with those from other techniques listed in literatures.

The levels of monoamine neurotransmitters and measures of mental and emotional health in HCV patients treated with ledipasvir (LDV) and sofosbuvir (SOF) with or without ribavirin (RBV).

Science.gov (United States)

Golabi, Pegah; Elsheikh, Elzafir; Karrar, Azza; Estep, James M; Younossi, Issah; Stepanova, Maria; Gerber, Lynn; Younossi, Zobair M

2016-11-01

Mental and emotional health (MEH) impairment is commonly encountered in hepatitis C patients. Although the exact mechanism remains unknown, alterations in neurotransmitter and cytokine levels maybe associated with hepatitis C virus (HCV)-related MEH issues.The aim of the study was to assess association of serum biomarkers with self-reports of MEH in HCV patients before treatment and after achieving sustained virologic response (SVR).The HCV genotype-1-infected patients who achieved SVR at 12 weeks after treatment with ledipasvir (LDV)/sofosbuvir (SOF) ± ribavirin (RBV) were selected. Frozen serum samples from baseline, end of treatment (EOT), and posttreatment week 4 (PTW4) were used to assay 16 cytokines and monoamine neurotransmitters. Validated self-reports were used to assess MEH.Hundred patients were evaluated. Mean age was 53 years (57% male, 86% white). Compared with baseline, emotional well-being and emotional health significantly increased by EOT, and role emotional, emotional well-being, and emotional health significantly increased at PTW4 in the RBV-containing arm (P neurotransmitters and cytokines were found to be independent predictors of MEH scores in multiple regression analysis.Cytokine and neurotransmitter changes are associated with mental and emotional health. Patient-reported outcome scores change during and after treatment.

Inter-scan reproducibility of coronary calcium measurement using Multi Detector-Row Computed Tomography (MDCT)

International Nuclear Information System (INIS)

Sabour, Siamak; Rutten, A.; Schouw, Y. T. van der; Atsma, F.; Grobbee, D. E.; Mali, W. P.; Bartelink, M. E. L.; Bots, M. L.; Prokop, M.

2007-01-01

Purpose. To assess inter-scan reproducibility of coronary calcium measurements obtained from Multi Detector-Row CT (MDCT) images and to evaluate whether this reproducibility is affected by different measurement protocols, slice thickness, cardiovascular risk factors and/or technical variables.Design. Cross-sectional study with repeated measurements. Materials and methods. The study population comprised 76 healthy women. Coronary calcium was assessed in these women twice in one session using 16-MDCT (Philips Mx 8000 IDT 16). Images were reconstructed with 1.5 mm slice thickness and 3.0 mm slice thickness. The 76 repeated scans were scored. The Agatston score, a volume measurement and a mass measurement were assessed. Reproducibility was determined by estimation of mean, absolute, relative difference, the weighted kappa value for agreement and the Intra-class correlation coefficient (ICCC).Results. Fifty-five participants (72.4%) had a coronary calcification of more than zero in Agatston (1.5 mm slice thickness). The reproducibility of coronary calcium measurements between scans in terms of ranking was excellent with Intra-class correlation coefficients of >0.98, and kappa values above 0.80. The absolute difference in calcium score between scans increased with increasing calcium levels, indicating that measurement error increases with increasing calcium levels. However, no relation was found between the mean difference in scores and calcium levels, indicating that the increase in measurement error is likely to result in random misclassification in calcium score. Reproducibility results were similar for 1.5 mm slices and for 3.0 mm slices, and equal for Agatston, volume and mass measurements.Conclusion. Inter-scan reproducibility of measurement of coronary calcium using images from MDCT is excellent, irrespective of slice thickness and type of calcium parameter

Aspects of scanning force microscope probes and their effects on dimensional measurement

Energy Technology Data Exchange (ETDEWEB)

Yacoot, Andrew [National Physical Laboratory, Teddington, Middlesex TW11 0LW (United Kingdom); Koenders, Ludger [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)], E-mail: andrew.yacoot@npl.co.uk

2008-05-21

The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements. (topical review)

Aspects of scanning force microscope probes and their effects on dimensional measurement

International Nuclear Information System (INIS)

Yacoot, Andrew; Koenders, Ludger

2008-01-01

The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements. (topical review)

Group velocity measurement using spectral interference in near-field scanning optical microscopy

International Nuclear Information System (INIS)

Mills, John D.; Chaipiboonwong, Tipsuda; Brocklesby, William S.; Charlton, Martin D. B.; Netti, Caterina; Zoorob, Majd E.; Baumberg, Jeremy J.

2006-01-01

Near-field scanning optical microscopy provides a tool for studying the behavior of optical fields inside waveguides. In this experiment the authors measure directly the variation of group velocity between different modes of a planar slab waveguide as the modes propagate along the guide. The measurement is made using the spectral interference between pulses propagating inside the waveguide with different group velocities, collected using a near-field scanning optical microscope at different points down the guide and spectrally resolved. The results are compared to models of group velocities in simple guides

Evaluation of positional plagiocephaly: Conventional anthropometric measurement versus laser scanning method.

Science.gov (United States)

Nahles, Susanne; Klein, Martin; Yacoub, Anke; Neyer, Julia

2018-01-01

The incidence of plagiocephaly has increased in the 25 years since the "Back to Sleep" campaign in 1991 to prevent sudden infant death. Plagiocephaly is not considered to be a pathological condition. It is more of an esthetic impairment and could have potentially negative psychological or psychosocial consequences; therefore, treatment is recommended. The aim of this study is to compare conventional anthropometry and laser scanning - two different measurement methods - as diagnostic instruments for plagiocephaly. The present study also tests the measurement time of both methods and whether one method is easier on the patient than the other. A total of 44 children (21 girls, 23 boys) with a mean age of 8.8 months were involved in the present study. Of all patients, the following parameters were routinely evaluated using a standard protocol with the conventional anthropometric method and the scan method: head circumference, head length, head width, head diagonals, and distances ex-t. Furthermore, the time required to obtain measurements and the behavior of the children during measurement were documented. For statistical analysis, a t-test and a Wilcoxon test were used to analyze differences between the two methods. The results for head circumference showed a mean of 441.5 mm for the anthropometric measurements and 441.6 mm for the scan method, with no significant difference between the two methods. A significant difference was found regarding the head width, head length, diagonals, and distance ex-t. The measurement process using the scan method needed a mean of 579.6 s in contrast to the manual anthropometric method, which required a mean time of 180.5 s. In comparison with the conventional anthropometric method, measurements made with a 3D laser scanner yield inconsistent results. Moreover, the current state of technology of 3D cephalometry has no advantages compared with the conventional anthropometric method. Disadvantages worth mentioning appear to be the

Evaluation of the Wind Flow Variability Using Scanning Doppler Lidar Measurements

Science.gov (United States)

Sand, S. C.; Pichugina, Y. L.; Brewer, A.

2016-12-01

Better understanding of the wind flow variability at the heights of the modern turbines is essential to accurately assess of generated wind power and efficient turbine operations. Nowadays the wind energy industry often utilizes scanning Doppler lidar to measure wind-speed profiles at high spatial and temporal resolution.The study presents wind flow features captured by scanning Doppler lidars during the second Wind Forecast and Improvement Project (WFIP 2) sponsored by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration (NOAA). This 18-month long experiment in the Columbia River Basin aims to improve model wind forecasts complicated by mountain terrain, coastal effects, and numerous wind farms.To provide a comprehensive dataset to use for characterizing and predicting meteorological phenomena important to Wind Energy, NOAA deployed scanning, pulsed Doppler lidars to two sites in Oregon, one at Wasco, located upstream of all wind farms relative to the predominant westerly flow in the region, and one at Arlington, located in the middle of several wind farms.In this presentation we will describe lidar scanning patterns capable of providing data in conical, or vertical-slice modes. These individual scans were processed to obtain 15-min averaged profiles of wind speed and direction in real time. Visualization of these profiles as time-height cross sections allows us to analyze variability of these parameters with height, time and location, and reveal periods of rapid changes (ramp events). Examples of wind flow variability between two sites of lidar measurements along with examples of reduced wind velocity downwind of operating turbines (wakes) will be presented.

Fine Metal Mask 3-Dimensional Measurement by using Scanning Digital Holographic Microscope

Science.gov (United States)

Shin, Sanghoon; Yu, Younghun

2018-04-01

For three-dimensional microscopy, fast and high axial resolution are very important. Extending the depth of field for digital holographic is necessary for three-dimensional measurements of thick samples. We propose an optical sectioning method for optical scanning digital holography that is performed in the frequency domain by spatial filtering of a reconstructed amplitude image. We established a scanning dual-wavelength off-axis digital holographic microscope to measure samples that exhibit a large amount of coherent noise and a thickness larger than the depth of focus of the objective lens. As a demonstration, we performed a three-dimensional measurement of a fine metal mask with a reconstructed sectional phase image and filtering with a reconstructed amplitude image.

Measurements of ultrasonic waves by means of laser Doppler velocimeter and an experimental study of elastic wave propagation in inhomogeneous media; Laser doppler sokudokei ni yoru choonpa keisoku to ganseki wo mochiita fukinshitsu baishitsu no hado denpa model jikken

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, O; Sato, T [Geological Survey of Japan, Tsukuba (Japan); Lei, X [Dia Consultants Company, Tokyo (Japan)

1996-05-01

In the study of seismic wave propagation, a model experimenting technique has been developed using a laser Doppler velocimeter (LDV) as the sensor. This technique, not dependent on conventional piezoelectric devices, only irradiates the specimen with laser to measure the velocity amplitude on the target surface, eliminating the need for close contact between the specimen and sensor. In the experiment, elastic penetration waves with their noise levels approximately 0.05mm/s were observed upon application of vibration of 10{sup 6}-10{sup 5}Hz. The specimen was stainless steel or rock, and waveforms caught by the LDV and piezoelectric device were compared. As the result, it was found that the LDV is a powerful tool for effectively explaining elastic wave propagation in inhomogeneous media. The piezoelectric device fails to reproduce accurately the waves to follow the initial one while the LDV detect the velocity amplitude on the specimen surface in a wide frequency range encouraging the discussion over the quantification of observed waveforms. 10 refs., 7 figs.

Accuracy and reliability of linear cephalometric measurements from cone-beam computed tomography scans of a dry human skull.

Science.gov (United States)

Berco, Mauricio; Rigali, Paul H; Miner, R Matthew; DeLuca, Stephelynn; Anderson, Nina K; Will, Leslie A

2009-07-01

The purpose of this study was to determine the accuracy and reliability of 3-dimensional craniofacial measurements obtained from cone-beam computed tomography (CBCT) scans of a dry human skull. Seventeen landmarks were identified on the skull. CBCT scans were then obtained, with 2 skull orientations during scanning. Twenty-nine interlandmark linear measurements were made directly on the skull and compared with the same measurements made on the CBCT scans. All measurements were made by 2 operators on 4 separate occasions. The method errors were 0.19, 0.21, and 0.19 mm in the x-, y- and z-axes, respectively. Repeated measures analysis of variance (ANOVA) showed no significant intraoperator or interoperator differences. The mean measurement error was -0.01 mm (SD, 0.129 mm). Five measurement errors were found to be statistically significantly different; however, all measurement errors were below the known voxel size and clinically insignificant. No differences were found in the measurements from the 2 CBCT scan orientations of the skull. CBCT allows for clinically accurate and reliable 3-dimensional linear measurements of the craniofacial complex. Moreover, skull orientation during CBCT scanning does not affect the accuracy or the reliability of these measurements.

High resolution wind turbine wake measurements with a scanning lidar

DEFF Research Database (Denmark)

Herges, T. G.; Maniaci, D. C.; Naughton, B. T.

2017-01-01

High-resolution lidar wake measurements are part of an ongoing field campaign being conducted at the Scaled Wind Farm Technology facility by Sandia National Laboratories and the National Renewable Energy Laboratory using a customized scanning lidar from the Technical University of Denmark. One...

Focal depth measurement of scanning helium ion microscope

International Nuclear Information System (INIS)

Guo, Hongxuan; Itoh, Hiroshi; Wang, Chunmei; Zhang, Han; Fujita, Daisuke

2014-01-01

When facing the challenges of critical dimension measurement of complicated nanostructures, such as of the three dimension integrated circuit, characterization of the focal depth of microscopes is important. In this Letter, we developed a method for characterizing the focal depth of a scanning helium ion microscope (HIM) by using an atomic force microscope tip characterizer (ATC). The ATC was tilted in a sample chamber at an angle to the scanning plan. Secondary electron images (SEIs) were obtained at different positions of the ATC. The edge resolution of the SEIs shows the nominal diameters of the helium ion beam at different focal levels. With this method, the nominal shapes of the helium ion beams were obtained with different apertures. Our results show that a small aperture is necessary to get a high spatial resolution and high depth of field images with HIM. This work provides a method for characterizing and improving the performance of HIM.

Influence of material surface on the scanning error of a powder-free 3D measuring system.

Science.gov (United States)

Kurz, Michael; Attin, Thomas; Mehl, Albert

2015-11-01

This study aims to evaluate the accuracy of a powder-free three-dimensional (3D) measuring system (CEREC Omnicam, Sirona), when scanning the surface of a material at different angles. Additionally, the influence of water was investigated. Nine different materials were combined with human tooth surface (enamel) to create n = 27 specimens. These materials were: Controls (InCoris TZI and Cerec Guide Bloc), ceramics (Vitablocs® Mark II and IPS Empress CAD), metals (gold and amalgam) and composites (Tetric Ceram, Filtek Supreme A2B and A2E). The highly polished samples were scanned at different angles with and without water. The 216 scans were then analyzed and descriptive statistics were obtained. The height difference between the tooth and material surfaces, as measured with the 3D scans, ranged from 0.83 μm (±2.58 μm) to -14.79 μm (±3.45 μm), while the scan noise on the materials was between 3.23 μm (±0.79 μm) and 14.24 μm (±6.79 μm) without considering the control groups. Depending on the thickness of the water film, measurement errors in the order of 300-1,600 μm could be observed. The inaccuracies between the tooth and material surfaces, as well as the scan noise for the materials, were within the range of error for measurements used for conventional impressions and are therefore negligible. The presence of water, however, greatly affects the scan. The tested powder-free 3D measuring system can safely be used to scan different material surfaces without the prior application of a powder, although drying of the surface prior to scanning is highly advisable.

Fast-scanning heterodyne receiver for measurement of the electron cyclotron emission from high-temperature plasmas

International Nuclear Information System (INIS)

Efthimion, P.C.; Arunasalam, V.; Bitzer, R.; Campbell, L.; Hosea, J.C.

1979-03-01

A fast-scanning heterodyne receiver was developed that measures the fundamental cyclotron emission from the PLT plasma and thus ascertains the time evolution of the electron temperature profile. The receiver scans 60 to 90 GHz every 10 milliseconds and is interfaced to a computer for completely automated calibrated temperature measurements

Forest Resource Measurements by Combination of Terrestrial Laser Scanning and Drone Use

Science.gov (United States)

Cheung, K.; Katoh, M.; Horisawa, M.

2017-10-01

Using terrestrial laser scanning (TLS), forest attributes such as diameter at breast height (DBH) and tree location can be measured accurately. However, due to low penetration of laser pulses to tree tops, tree height measurements are typically underestimated. In this study, data acquired by TLS and drones were combined; DBH and tree locations were determined by TLS, and tree heights were measured by drone use. The average tree height error and root mean square error (RMSE) of tree height were 0.8 and 1.2 m, respectively, for the combined method, and -0.4 and 1.7 m using TLS alone. The tree height difference was compared using airborne laser scanning (ALS). Furthermore, a method to acquire 100 % tree detection rate based on TLS data is suggested in this study.

Accuracy of cancellous bone volume fraction measured by micro-CT scanning

DEFF Research Database (Denmark)

Ding, Ming; Odgaard, A; Hvid, I

1999-01-01

Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens...... which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner...

The size of thyroid gland measured by scan

International Nuclear Information System (INIS)

Choe, K. O.; Choe, Y. K.; Park, C. Y.; Choi, B. S.

1973-01-01

Normal size of thyroid gland in Korean male and female were aimed to study through color scanning using radioactive materials. The measurement of the size of thyroid gland is necessary not only for standardization of Korean subjects but also to the dose determination of radioactive iodine treatment and evaluation of thyroid disease. There had been no available data in regarding Korean euthyroid size in literature. In 119 subjects from the age of 19 years to 60 tears, who have normal thyroid function and no history of any thyroid disorder, the length, the width and the area of thyroid gland were measured in scan images. The weight of thyroid gland was calculated by Allen-Goodwin's formula. The thyroid scan was obtained by Picker Color Magna-Scanner, in 24 hours after ingestion of 50μCi sodium iodide 1-131. Results; In males, 16 subjects among 119 cases, the mean values were as following: length-5.1 cm, width-2.5 cm, area-9.1 cm 2 , weight-14.7 gr in right lobe, length-4.7 cm, width-2.3 cm, area-7.6 cm 2 , weight-11.1 gr in left lobe, total area-16.7 cm 2 , and total weight-25.8 gr. In females, 103 subjects among 119 cases, the mean values were as following: length-5.1 cm, width-2.4 cm, area-9.4 cm 2 , weight-15.2 gr in the right lobe, length-4.6 cm, width-2.2 cm, area-7.9 cm 2 , weight-11.6 gr in left lobe, total area-17.3 cm 2 , total weight-26.8 gr. The right lobe was larger in the above mean values of size than the left: 11% longer in length, 8% wider in width, 18% broader in area and 30% heavier in weight in mean values. The difference of sizes between two lobes was statistically significant. There was no significant difference comparison with English written literature

Comparison of conventional study model measurements and 3D digital study model measurements from laser scanned dental impressions

Science.gov (United States)

Nugrahani, F.; Jazaldi, F.; Noerhadi, N. A. I.

2017-08-01

The field of orthodontics is always evolving,and this includes the use of innovative technology. One type of orthodontic technology is the development of three-dimensional (3D) digital study models that replace conventional study models made by stone. This study aims to compare the mesio-distal teeth width, intercanine width, and intermolar width measurements between a 3D digital study model and a conventional study model. Twelve sets of upper arch dental impressions were taken from subjects with non-crowding teeth. The impressions were taken twice, once with alginate and once with polivinylsiloxane. The alginate impressions used in the conventional study model and the polivinylsiloxane impressions were scanned to obtain the 3D digital study model. Scanning was performed using a laser triangulation scanner device assembled by the School of Electrical Engineering and Informatics at the Institut Teknologi Bandung and David Laser Scan software. For the conventional model, themesio-distal width, intercanine width, and intermolar width were measured using digital calipers; in the 3D digital study model they were measured using software. There were no significant differences between the mesio-distal width, intercanine width, and intermolar width measurments between the conventional and 3D digital study models (p>0.05). Thus, measurements using 3D digital study models are as accurate as those obtained from conventional study models

Study on measurement of leading and trailing edges of blades based on optical scanning system

Science.gov (United States)

Chao, Bi; Liu, Hongguang; Bao, Longxiang; Li, Di

2017-10-01

In the field of aeronautics, the geometry and dimensional accuracy of the blade edges has a large influence on the aerodynamic performance of aero engine. Therefore, a non-contact optical scanning system is established to realize the measurement of leading and trailing edges of blades in a rapid, precise and efficient manner in the paper. Based on the mechanical framework of a traditional CMM, the system is equipped with a specified sensing device as the scanning probe, which is made up by two new-style laser scanning sensors installed at a certain angle to each other by a holder. In the measuring procedure, the geometric dimensions of the measured blade edges on every contour plane are determined by the contour information on five transversals at the leading or trailing edges, which can be used to determine the machining allowance of the blades. In order to verify the effectiveness and practicality of the system set up, a precision forging blade after grinded is adopted as the measured object and its leading and trailing edges are measured by the system respectively. In the experiment, the thickness of blade edges on three contour planes is measured by the optical scanning system several times. As the experiment results show, the repeatability accuracy of the system can meet its design requirements and the inspecting demands of the blade edges. As a result, the optical scanning system could serve as a component of the intelligent manufacturing system of blades to improve the machining quality of the blade edges.

3D laser scanning in civil engineering - measurements of volume of earth masses

Science.gov (United States)

Pawłowicz, J. A.; Szafranko, E.; Harasymiuk, J.

2018-03-01

Considering the constant drive to improve and accelerate building processes as well as possible applications of the latest technological achievements in civil engineering practice, the author has proposed to use 3D laser scanning in the construction industry. For example, data achieved through a 3D laser scanning process will facilitate making inventories of parameters of buildings in a very short time, will enable one to check irregularly shaped masses of earth, heavy and practically impossible to calculate precisely using traditional techniques. The other part of the research, performed in the laboratory, consisted of measurements of a model mound of earth. All the measurements were made with a 3D SkanStation C10 laser scanner manufactured by Leica. The data were analyzed. The results suggest that there are great opportunities for using the laser scanning technology in civil engineering

APPLICABILITY OF THE COBB ANGLE MEASUREMENT IN IDIOPATHIC SCOLIOSIS USING SCANNED IMAGING

Directory of Open Access Journals (Sweden)

ERASMO DE ABREU ZARDO

Full Text Available ABSTRACT Objectives: To compare the measurement of the Cobb angle on printed radiographs and on scanned radiographs viewed through the software "PixViewer". Methods: Preoperative radiographs of 23 patients were evaluated on printed films and through the software "PixViewer". The same evaluator, a spine surgeon, chose the proximal and distal limiting vertebrae of the main curve on printed radiographs, without identification of patients, and measured the Cobb angle based on these parameters. The same parameters and measurements were applied to scanned radiographs. The measurements were compared, as well as the choice of limiting vertebrae. Results: The average variation of the Cobb angle between methods was 1.48 ± 1.73°. The intraclass correlation coefficient (ICC was 0.99, demonstrating excellent reproducibility. Conclusion: The Cobb method can be used to evaluate scoliosis through the "PixViewer" tool with the same reliability as the classic method on printed radiographs.

Continuous versus step-by-step scanning mode of a novel 3D scanner for CyberKnife measurements

International Nuclear Information System (INIS)

Al Kafi, M Abdullah; Mwidu, Umar; Moftah, Belal

2015-01-01

The purpose of the study is to investigate the continuous versus step-by-step scanning mode of a commercial circular 3D scanner for commissioning measurements of a robotic stereotactic radiosurgery system. The 3D scanner was used for profile measurements in step-by-step and continuous modes with the intent of comparing the two scanning modes for consistency. The profile measurements of in-plane, cross-plane, 15 degree, and 105 degree were performed for both fixed cones and Iris collimators at depth of maximum dose and at 10 cm depth. For CyberKnife field size, penumbra, flatness and symmetry analysis, it was observed that the measurements with continuous mode, which can be up to 6 times faster than step-by-step mode, are comparable and produce scans nearly identical to step-by-step mode. When compared with centered step-by-step mode data, a fully processed continuous mode data gives rise to maximum of 0.50% and 0.60% symmetry and flatness difference respectfully for all the fixed cones and Iris collimators studied. - Highlights: • D scanner for CyberKnife beam data measurements. • Beam data analysis for continuous and step-by-step scan modes. • Faster continuous scanning data are comparable to step-by-step mode scan data.

Pavement cracking measurements using 3D laser-scan images

International Nuclear Information System (INIS)

Ouyang, W; Xu, B

2013-01-01

Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel −1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s −1 , allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions. (paper)

Poster - 25: Neutron Spectral Measurements around a Scanning Proton Beam

Energy Technology Data Exchange (ETDEWEB)

Kildea, John; Enger, Shirin; Maglieri, Robert; Mirzakhanian, Lalageh; Dahlgren, Christina Vallhagen; Dubeau, Jacques; Witharana, Sanjeeva [Medical Physics Unit, McGill University Health Centre, Medical Physics Unit, McGill University, Medical Physics Unit, McGill University, Medical Physics Unit, McGill University, Skandion Clinic, Detec Inc., Gatineau, Quebec, Detec Inc., Gatineau, Quebec (Canada)

2016-08-15

We describe the measurements of neutron spectra that we undertook around a scanning proton beam at the Skandion proton therapy clinic in Uppsala, Sweden. Measurements were undertaken using an extended energy range Nested Neutron Spectrometer (NNS, Detec Inc., Gatineau, QC) operated in pulsed and current mode. Spectra were measured as a function of location in the treatment room and for various Bragg peak depths. Our preliminary unfolded data clearly show the direct, evaporation and thermal neutron peaks and we can show the effect on the neutron spectrum of a water phantom in the primary proton beam.

Beam diffusion measurements using collimator scans in the LHC

CERN Document Server

Valentino, Gianluca; Bruce, Roderik; Burkart, Florian; Previtali, Valentina; Redaelli, Stefano; Salvachua, Belen; Stancari, Giuliov; Valishev, Alexander

2013-01-01

The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

Segmented gamma scanning method for measuring holdup in the spherical container

International Nuclear Information System (INIS)

Deng Jingshan; Li Ze; Gan Lin; Lu Wenguang; Dong Mingli

2007-01-01

Some special nuclear material (SNM) is inevitably deposited in the facilities (mixer, reactor) of nuclear material process line. Exactly knowing the quantity of nuclear material holdup is very important for nuclear material accountability and critical safety. This paper presents segmented gamma scanning method for SNM holdup measurement of spherical container, at the left, right and back of which other equipments exist so that the detectors can be put at the only front of container for measurement. The nuclear material deposited in the spherical container can be looked as spherical shell source, which is divided into many layers. The detectors scanning spherical shell source are moved layer by layer from the top to the bottom to obtain projection data, with which deposited material distribution can be reconstructed by using Least Square (LS) method or Maximum Likelihood (ML) method. With these methods accurate total holdup can be obtained by summing up all the segmental values reconstructed. In this paper this measurement method for holdup in the spherical container was verified with Monte-Carlo simulation calculation and experiment. (authors)

Automatic Gamma-Scanning System for Measurement of Residual Heat in Spent Nuclear Fuel

International Nuclear Information System (INIS)

Osifo, Otasowie

2007-03-01

In Sweden, spent nuclear fuel will be encapsulated and placed in a deep geological repository. In this procedure, reliable and accurate spent fuel data such as discharge burnup, cooling time and residual heat must be available. The gamma scanning method was proposed in earlier work as a fast and reliable method for the experimental determination of such spent fuel data. This thesis is focused on the recent achievements in the development of a pilot gamma scanning system and its application in measuring spent fuel residual heat. The achievements include the development of dedicated spectroscopic data-acquisition and analysis software and the use of a specially designed calorimeter for calibrating the gamma scanning system. The pilot system is described, including an evaluation of the performance of the spectrum analysis software. Also described are the gamma-scanning measurements on 31 spent PWR fuel assemblies performed using the pilot system. The results obtained for the determination of residual heat are presented, showing an agreement of (2-3) % with both calorimetric and calculated data. In addition, the ability to verify declared data such as discharge burnup and cooling time is demonstrated

Simultaneous measurement of spectral sky radiance by a non-scanning multidirectional spectroradiometer (MUDIS)

International Nuclear Information System (INIS)

Riechelmann, Stefan; Schrempf, Michael; Seckmeyer, Gunther

2013-01-01

We present a novel non-scanning multidirectional spectroradiometer (MUDIS) measuring the spectral sky radiance as a function of zenith and azimuth angle with a high spectral and temporal resolution. The instrument is based on a hyperspectral imager and measures spectral sky radiance in the wavelength range of 250–600 nm at 113 different directions simultaneously. MUDIS has been intercalibrated with a sky scanning CCD spectroradiometer (SCCD). Sky radiance measurements have been performed with both instruments under cloudless and overcast sky. The spectral actinic irradiance derived from those measurements agrees within 8% for wavelengths higher than 320 nm. The bias between synchronous MUDIS and SCCD sky radiance measurements during cloudless and overcast sky is below 5% for 320 and 500 nm with a 1σ standard deviation of less than 10%. MUDIS enables us to perform more than 220 000 spectral sky radiance measurements instead of approximately 6000 SCCD spectral sky radiance measurements per day and to measure spatial variations of spectral sky radiance simultaneously. (paper)

Measuring a narrow Bessel beam spot by scanning a charge-coupled device (CCD) pixel

International Nuclear Information System (INIS)

Tiwari, S K; Ram, S P; Jayabalan, J; Mishra, S R

2010-01-01

By scanning a charge-coupled device (CCD) camera transverse to the beam axis and observing the variation in counts on a marked pixel, we demonstrate that we can measure a laser beam spot size smaller than the size of the CCD-pixel. We find this method particularly attractive for measuring the size of central spot of a Bessel beam, for which the established scanning knife-edge method does not work appropriately because of the large contribution of the rings surrounding the central spot to the signal

TOPICAL REVIEW: Aspects of scanning force microscope probes and their effects on dimensional measurement

Science.gov (United States)

Yacoot, Andrew; Koenders, Ludger

2008-05-01

The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements.

Beam diffusion measurements using collimator scans in the LHC

Directory of Open Access Journals (Sweden)

Gianluca Valentino

2013-02-01

Full Text Available The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

Atmospheric correction for JPSS-2 VIIRS response versus scan angle measurements

Science.gov (United States)

McIntire, Jeffrey; Moeller, Chris; Oudrari, Hassan; Xiong, Xiaoxiong

2017-09-01

The Joint Polar Satellite System 2 (JPSS-2) Visible Infrared Imaging Radiometer Suite (VIIRS) includes one spectral band centered in a strong atmospheric absorption region. As much of the pre-launch calibration is performed under laboratory ambient conditions, accurately accounting for the absorption, and thereby ensuring the transfer of the sensor calibration to on-orbit operations, is necessary to generate science quality data products. This work is focused on the response versus scan angle (RVS) measurements, which characterize the relative scan angle dependent reflectance of the JPSS-2 VIIRS instrument optics. The spectral band of interest, centered around 1378 nm, is within a spectral region strongly effected by water vapor absorption. The methodology used to model the absolute humidity and the atmospheric transmittance under the laboratory conditions is detailed. The application of this transmittance to the RVS determination is then described including an uncertainty estimate; a comparison to the pre-launch measurements from earlier sensor builds is also performed.

Spatial filtering velocimeter for vehicle navigation with extended measurement range

Science.gov (United States)

He, Xin; Zhou, Jian; Nie, Xiaoming; Long, Xingwu

2015-05-01

The idea of using spatial filtering velocimeter is proposed to provide accurate velocity information for vehicle autonomous navigation system. The presented spatial filtering velocimeter is based on a CMOS linear image sensor. The limited frame rate restricts high speed measurement of the vehicle. To extend measurement range of the velocimeter, a method of frequency shifting is put forward. Theoretical analysis shows that the frequency of output signal can be reduced and the measurement range can be doubled by this method when the shifting direction is set the same with that of image velocity. The approach of fast Fourier transform (FFT) is employed to obtain the power spectra of the spatially filtered signals. Because of limited frequency resolution of FFT, a frequency spectrum correction algorithm, called energy centrobaric correction, is used to improve the frequency resolution. The correction accuracy energy centrobaric correction is analyzed. Experiments are carried out to measure the moving surface of a conveyor belt. The experimental results show that the maximum measurable velocity is about 800deg/s without frequency shifting, 1600deg/s with frequency shifting, when the frame rate of the image is about 8117 Hz. Therefore, the measurement range is doubled by the method of frequency shifting. Furthermore, experiments were carried out to measure the vehicle velocity simultaneously using both the designed SFV and a laser Doppler velocimeter (LDV). The measurement results of the presented SFV are coincident with that of the LDV, but with bigger fluctuation. Therefore, it has the potential of application to vehicular autonomous navigation.

Pedicle measurement of the thoracolumbar spine: a cadaveric, radiographic, and CT scan study in Filipinos

International Nuclear Information System (INIS)

Molano, A.M.V.; Sison, A.B.; Fong, H.C.; Lim, N.T.; Sabile, K.

1994-01-01

With the popular usage of spinal pedicular screw fixation, it is essential to have a knowledge of the morphometry of the pedicles of the spine of particular populations. This study compared the direct pedicle measurements of ten cadavers in an institution, with their respective radiographic and computerized tomographic (CT) scan values, and also compared the effective pedicle diameter (EPD) with the conventional outer pedicle diameter (OPD) measurements. A compilation of pedicle values was also made in X-ray and CT scan plates of a Filipino population. A statistical analysis made on the 2,760 pedicle measurements taken from cadaveric T6-L5 vertebrae showed that direct measurements were significantly different from X-ray and CT scan values. The mean values of the EPD differed from those of the OPD, but not statistically significant. Comparison with previous foreign studies revealed significant differences in these pedicle dimensions. Pedicle measurements in a living Filipino population were found to be significantly different statistically between sexes. Accurate measurement of the pedicle diameters and lengths are indeed critical for the success of a spinal stabilization procedure using pedicular screws. (author). 8 refs.; 5 figs.; 1 tab

Tympanic, Infrared Skin, and Temporal Artery Scan Thermometers Compared with Rectal Measurement in Children: A Real-Life Assessment

Directory of Open Access Journals (Sweden)

Karel Allegaert, MD, PhD

2014-12-01

Conclusions: All noninvasive techniques underperformed compared with rectal measurement. The temporal artery scan deviations were smallest, but all noninvasive techniques overestimate lower temperatures and underestimate higher temperatures compared with rectal measurement. In our hands, temporal artery scan measurement seems to be second best, but not yet ideal.

Measurement of gastric emptying rate in humans. Simplified scanning method

Energy Technology Data Exchange (ETDEWEB)

Holt, S.; Colliver, J.; Guram, M.; Neal, C.; Verhulst, S.J.; Taylor, T.V. (Univ. of South Carolina School of Medicine, Columbia (USA))

1990-11-01

Simultaneous measurements of the gastric emptying rate of the solid and liquid phase of a dual-isotope-labeled test meal were made using a gamma camera and a simple scintillation detector, similar to that used in a hand-held probe. A simple scanning apparatus, similar to that used in a hand-held scintillation probe, was compared with simultaneous measurements made by a gamma camera in 16 healthy males. A dual-labeled test meal was utilized to measure liquid and solid emptying simultaneously. Anterior and posterior scans were taken at intervals up to 120 min using both a gamma camera and the scintillation probe. Good relative agreement between the methods was obtained both for solid-phase (correlation range 0.92-0.99, mean 0.97) and for liquid-phase data (correlation range 0.93-0.99, mean 0.97). For solid emptying data regression line slopes varied from 0.75 to 1.03 (mean 0.84). Liquid emptying data indicated that slopes ranged from 0.71 to 1.06 (mean 0.87). These results suggested that an estimate of the gamma measurement could be obtained by multiplying the scintillation measurement by a factor of 0.84 for the solid phase and 0.87 for the liquid phase. Correlation between repeat studies was 0.97 and 0.96 for solids and liquids, respectively. The application of a hand-held probe technique provides a noninvasive and inexpensive method for accurately assessing solid- and liquid-phase gastric emptying from the human stomach that correlates well with the use of a gamma camera, within the range of gastric emptying rate in the normal individuals in this study.

Measurement of gastric emptying rate in humans. Simplified scanning method

International Nuclear Information System (INIS)

Holt, S.; Colliver, J.; Guram, M.; Neal, C.; Verhulst, S.J.; Taylor, T.V.

1990-01-01

Simultaneous measurements of the gastric emptying rate of the solid and liquid phase of a dual-isotope-labeled test meal were made using a gamma camera and a simple scintillation detector, similar to that used in a hand-held probe. A simple scanning apparatus, similar to that used in a hand-held scintillation probe, was compared with simultaneous measurements made by a gamma camera in 16 healthy males. A dual-labeled test meal was utilized to measure liquid and solid emptying simultaneously. Anterior and posterior scans were taken at intervals up to 120 min using both a gamma camera and the scintillation probe. Good relative agreement between the methods was obtained both for solid-phase (correlation range 0.92-0.99, mean 0.97) and for liquid-phase data (correlation range 0.93-0.99, mean 0.97). For solid emptying data regression line slopes varied from 0.75 to 1.03 (mean 0.84). Liquid emptying data indicated that slopes ranged from 0.71 to 1.06 (mean 0.87). These results suggested that an estimate of the gamma measurement could be obtained by multiplying the scintillation measurement by a factor of 0.84 for the solid phase and 0.87 for the liquid phase. Correlation between repeat studies was 0.97 and 0.96 for solids and liquids, respectively. The application of a hand-held probe technique provides a noninvasive and inexpensive method for accurately assessing solid- and liquid-phase gastric emptying from the human stomach that correlates well with the use of a gamma camera, within the range of gastric emptying rate in the normal individuals in this study

Demonstration and uncertainty analysis of synchronised scanning lidar measurements of 2-D velocity fields in a boundary-layer wind tunnel

DEFF Research Database (Denmark)

van Dooren, Marijn Floris; Campagnolo, Filippo; Sjöholm, Mikael

2017-01-01

to demonstrate the benefits of synchronised scanning lidars in such experimental surroundings for the first time. The duallidar system can provide fully synchronised trajectory scans with sampling timescales ranging from seconds to minutes. First, staring mode measurements were compared to hot-wire probe...... as wake area scans were executed to illustrate the applicability of lidar scanning to the measurement of small-scale wind flow effects. An extensive uncertainty analysis was executed to assess the accuracy of the method. The downsides of lidar with respect to the hotwire probes are the larger measurement...... probe volume, which compromises the ability to measure turbulence, and the possible loss of a small part of the measurements due to hard target beam reflection. In contrast, the benefits are the high flexibility in conducting both point measurements and area scanning and the fact that remote sensing...

Potential errors in optical density measurements due to scanning side in EBT and EBT2 Gafchromic film dosimetry.

Science.gov (United States)

Desroches, Joannie; Bouchard, Hugo; Lacroix, Frédéric

2010-04-01

The purpose of this study is to determine the effect on the measured optical density of scanning on either side of a Gafchromic EBT and EBT2 film using an Epson (Epson Canada Ltd., Toronto, Ontario) 10000XL flat bed scanner. Calibration curves were constructed using EBT2 film scanned in landscape orientation in both reflection and transmission mode on an Epson 10000XL scanner. Calibration curves were also constructed using EBT film. Potential errors due to an optical density difference from scanning the film on either side ("face up" or "face down") were simulated. Scanning the film face up or face down on the scanner bed while keeping the film angular orientation constant affects the measured optical density when scanning in reflection mode. In contrast, no statistically significant effect was seen when scanning in transmission mode. This effect can significantly affect relative and absolute dose measurements. As an application example, the authors demonstrate potential errors of 17.8% by inverting the film scanning side on the gamma index for 3%-3 mm criteria on a head and neck intensity modulated radiotherapy plan, and errors in absolute dose measurements ranging from 10% to 35% between 2 and 5 Gy. Process consistency is the key to obtaining accurate and precise results in Gafchromic film dosimetry. When scanning in reflection mode, care must be taken to place the film consistently on the same side on the scanner bed.

Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope

DEFF Research Database (Denmark)

Jensen, Carsten P.

Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope......Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope...

Measurement of position and profile of undulator radiation in Indus-2 using scanning wire monitor

International Nuclear Information System (INIS)

Kant, Chander; Lal, Sohan; Raghuwanshi, V.K.; Prasad, Vijendra

2015-01-01

Two planar undulators (U1 and U2) for Atomic Molecular Spectroscopy (AMOS) beamline and Angle Resolved Photoelectron Spectroscopy (ARPES) beamline have been installed in Indus-2. The U1 undulator is designed to produce photons in the energy range of 6 eV to 250 eV and U2 undulator is designed to produce photons in the energy range of 30 eV to 600 eV. In order to measure the position and vertical profile of photon beams emitted from these undulators, one scanning wire monitor has been installed in each beamline front end. In these scanning wire monitors, a gold coated tungsten wire of 100 μm thickness, stretched between a fork shaped alumina ceramic holder, is scanned vertically perpendicular to the direction of propagation of photon beam by using a precisely controlled stepper motor. The photo-electron current generated in the wire is measured by an electrometer. A graphical user interface has been developed which facilitates the scanning as per the given range, plots the graphs and stores the scanned data in Excel file. This paper describes our experience and usefulness of these wire monitors during commissioning of planar undulators in Indus-2. (author)

Fundamentals of overlay measurement and inspection using scanning electron-microscope

Science.gov (United States)

Kato, T.; Okagawa, Y.; Inoue, O.; Arai, K.; Yamaguchi, S.

2013-04-01

Scanning electron-microscope (SEM) has been successfully applied to CD measurement as promising tools for qualifying and controlling quality of semiconductor devices in in-line manufacturing process since 1985. Furthermore SEM is proposed to be applied to in-die overlay monitor in the local area which is too small to be measured by optical overlay measurement tools any more, when the overlay control limit is going to be stringent and have un-ignorable dependence on device pattern layout, in-die location, and singular locations in wafer edge, etc. In this paper, we proposed new overlay measurement and inspection system to make an effective use of in-line SEM image, in consideration of trade-off between measurement uncertainty and measurement pattern density in each SEM conditions. In parallel, we make it clear that the best hybrid overlay metrology is in considering each tool's technology portfolio.

Optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy in retinal nerve fiber layer measurements of glaucoma patients.

Science.gov (United States)

Fanihagh, Farsad; Kremmer, Stephan; Anastassiou, Gerasimos; Schallenberg, Maurice

2015-01-01

To determine the correlations and strength of association between different imaging systems in analyzing the retinal nerve fiber layer (RNFL) of glaucoma patients: optical coherence tomography (OCT), scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (CSLO). 114 eyes of patients with moderate open angle glaucoma underwent spectral domain OCT (Topcon SD-OCT 2000 and Zeiss Cirrus HD-OCT), SLP (GDx VCC and GDx Pro) and CSLO (Heidelberg Retina Tomograph, HRT 3). Correlation coefficients were calculated between the structural parameters yielded by these examinations. The quantitative relationship between the measured RNFL thickness globally and for the four regions (superior, inferior, nasal, temporal) were evaluated with different regression models for all used imaging systems. The strongest correlation of RNFL measurements was found between devices using the same technology like GDx VCC and GDx Pro as well as Topcon OCT and Cirrus OCT. In glaucoma patients, the strongest associations (R²) were found between RNFL measurements of the two optical coherence tomography devices Topcon OCT and Cirrus OCT (R² = 0.513) and between GDx VCC and GDx Pro (R² = 0.451). The results of the OCTs and GDX Pro also had a strong quantitative relationship (Topcon OCT R² = 0.339 and Cirrus OCT R² = 0.347). GDx VCC and the OCTs showed a mild to moderate association (Topcon OCT R² = 0.207 and Cirrus OCT R² = 0.258). The confocal scanning laser ophthalmoscopy (HRT 3) had the lowest association to all other devices (Topcon OCT R² = 0.254, Cirrus OCT R² = 0.158, GDx Pro R² = 0.086 and GDx VCC R² = 0.1). The measurements of the RNFL in glaucoma patients reveal a high correlation of OCT and GDx devices because OCTs can measure all major retinal layers and SLP can detect nerve fibers allowing a comparison between the results of this devices. However, CSLO by means of HRT topography can only measure height values of the retinal surface but it cannot distinguish

Mobile seismic exploration

Energy Technology Data Exchange (ETDEWEB)

Dräbenstedt, A., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de; Seyfried, V. [Research & Development, Polytec GmbH, Waldbronn (Germany); Cao, X.; Rembe, C., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Institute of Electrical Information Technology, TU Clausthal, Clausthal-Zellerfeld (Germany); Polom, U., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Leibniz Institute of Applied Geophysics, Hannover (Germany); Pätzold, F.; Hecker, P. [Institute of Flight Guidance, TU Braunschweig, Braunschweig (Germany); Zeller, T. [Clausthaler Umwelttechnik Institut CUTEC, Clausthal-Zellerfeld (Germany)

2016-06-28

Laser-Doppler-Vibrometry (LDV) is an established technique to measure vibrations in technical systems with picometer vibration-amplitude resolution. Especially good sensitivity and resolution can be achieved at an infrared wavelength of 1550 nm. High-resolution vibration measurements are possible over more than 100 m distance. This advancement of the LDV technique enables new applications. The detection of seismic waves is an application which has not been investigated so far because seismic waves outside laboratory scales are usually analyzed at low frequencies between approximately 1 Hz and 250 Hz and require velocity resolutions in the range below 1 nm/s/√Hz. Thermal displacements and air turbulence have critical influences to LDV measurements at this low-frequency range leading to noise levels of several 100 nm/√Hz. Commonly seismic waves are measured with highly sensitive inertial sensors (geophones or Micro Electro-Mechanical Sensors (MEMS)). Approaching a laser geophone based on LDV technique is the topic of this paper. We have assembled an actively vibration-isolated optical table in a minivan which provides a hole in its underbody. The laser-beam of an infrared LDV assembled on the optical table impinges the ground below the car through the hole. A reference geophone has detected remaining vibrations on the table. We present the results from the first successful experimental demonstration of contactless detection of seismic waves from a movable vehicle with a LDV as laser geophone.

Scanning laser polarimetry retinal nerve fiber layer thickness measurements after LASIK.

Science.gov (United States)

Zangwill, Linda M; Abunto, Teresa; Bowd, Christopher; Angeles, Raymund; Schanzlin, David J; Weinreb, Robert N

2005-02-01

To compare retinal nerve fiber layer (RNFL) thickness measurements before and after LASIK. Cohort study. Twenty participants undergoing LASIK and 14 normal controls. Retinal nerve fiber layer thickness was measured before LASIK and approximately 3 months after surgery in one eye each of 20 patients using a scanning laser polarimeter (GDx Nerve Fiber Analyzer) with fixed corneal compensation (FCC), one with variable corneal compensation (GDx VCC), and optical coherence tomography (OCT). Fourteen normal controls also were tested at baseline and approximately 3 months later. Retinal nerve fiber layer thicknesses measured with the GDx FCC, GDx VCC, and OCT. At baseline, mean (95% confidence interval [CI]) RNFL thicknesses for the GDx FCC, GDx VCC, and OCT were 78.1 microm (72.2-83.9), 54.3 microm (52.7-56.0), and 96.8 microm (93.2-100.5), respectively. In both LASIK and control groups, there were no significant changes between baseline and follow-up examinations in GDx VCC and OCT RNFL thickness measurements globally or in the superior and inferior quadrants (mean change, FCC measurements between baseline and follow-up. In LASIK patients, significant reductions were observed in GDx FCC RNFL measurements. Average absolute values of the mean (95% CI) change in thickness were 12.4 microm (7.7-17.2), 15.3 microm (9.6-20.9), and 12.9 microm (7.6-18.1) for GDx FCC RNFL measurements superiorly, inferiorly, and globally, respectively (all Ps FCC RNFL thickness measurements after LASIK is a measurement artifact and is most likely due to erroneous compensation for corneal birefringence. With scanning laser polarimetry, it is mandatory to compensate individually for change in corneal birefringence after LASIK to ensure accurate RNFL assessment.

Scan path entropy and Arrow plots: Capturing scanning behavior of multiple observers

Directory of Open Access Journals (Sweden)

Ignace T C Hooge

2013-12-01

Full Text Available Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures 1 scan path entropy to quantify gaze guidance and 2 the arrow plot to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50. The new measures were tested in an eye tracking study (48 observers, 39 advertisements. Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place.

Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter

Directory of Open Access Journals (Sweden)

Nobutomo Morita

2018-01-01

Full Text Available The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces—such as metal, paper, film, and so on—thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV by modifying the design which was adopted from MEMS (microelectromechanical systems fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects—aluminum block, wood block, and white acrylic block—considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter.

Science.gov (United States)

Morita, Nobutomo; Nogami, Hirofumi; Higurashi, Eiji; Sawada, Renshi

2018-01-23

The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV) and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces-such as metal, paper, film, and so on-thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV) by modifying the design which was adopted from MEMS (microelectromechanical systems) fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects-aluminum block, wood block, and white acrylic block-considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

Transverse emittance measurement at REGAE via a solenoid scan

Energy Technology Data Exchange (ETDEWEB)

Hachmann, Max

2012-12-15

The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required. A quantity to rate the beam quality is the beam emittance. In the course of this thesis transverse emittance measurements by a solenoid scan could be realized and beyond that an improved theoretical description of a solenoid was successful. The foundation of emittance measurements are constituted by theoretical models which describe the envelope of a beam. Two different models were derived. The first is an often used model to determine the transverse beam emittance without considering space charge effects. More interesting and challenging was the development of an envelope model taking space charge effects into account. It is introduced and cross checked with measurements and simulations.

Micro-four-point probes in a UHV scanning electron microscope for in-situ surface-conductivity measurements

DEFF Research Database (Denmark)

Shiraki, I.; Nagao, T.; Hasegawa, S.

2000-01-01

For in-situ measurements of surface conductivity in ultrahigh vacuum (UHV), we have installed micro-four-point probes (probe spacings down to 4 mum) in a UHV scanning electron microscope (SEM) combined with scanning reflection-high-energy electron diffraction (RHEED). With the aid of piezoactuators...

Investigation on the traceability of three dimensional scanning electron microscope measurements based on the stereo-pair technique

DEFF Research Database (Denmark)

Bariani, Paolo; De Chiffre, Leonardo; Hansen, Hans Nørgaard

2005-01-01

An investigation was carried out concerning the traceability of dimensional measurements performed with the scanning electron microscope (SEM) using reconstruction of surface topography through stereo-photogrammetry. A theoretical description of the effects that the main instrumental variables...... with the scanning electron microscope (SEM) using reconstruction of surface topography through stereo-photogrammetry. A theoretical description of the effects that the main instrumental variables and measurement parameters have on the reconstruction accuracy of any point on the surface of the object being imaged......-dimensional topography of the type C roughness standards showed good agreement with the nominal profile wavelength values. An investigation was carried out concerning the traceability of dimensional measurements performed with the scanning electron microscope (SEM) using reconstruction of surface topography through...

Note: long range and accurate measurement of deep trench microstructures by a specialized scanning tunneling microscope.

Science.gov (United States)

Ju, Bing-Feng; Chen, Yuan-Liu; Zhang, Wei; Zhu, Wule; Jin, Chao; Fang, F Z

2012-05-01

A compact but practical scanning tunneling microscope (STM) with high aspect ratio and high depth capability has been specially developed. Long range scanning mechanism with tilt-adjustment stage is adopted for the purpose of adjusting the probe-sample relative angle to compensate the non-parallel effects. A periodical trench microstructure with a pitch of 10 μm has been successfully imaged with a long scanning range up to 2.0 mm. More innovatively, a deep trench with depth and step height of 23.0 μm has also been successfully measured, and slope angle of the sidewall can approximately achieve 67°. The probe can continuously climb the high step and exploring the trench bottom without tip crashing. The new STM could perform long range measurement for the deep trench and high step surfaces without image distortion. It enables accurate measurement and quality control of periodical trench microstructures.

Image-scanning measurement using video dissection cameras

International Nuclear Information System (INIS)

Carson, J.S.

1978-01-01

A high speed dimensional measuring system capable of scanning a thin film network, and determining if there are conductor widths, resistor widths, or spaces not typical of the design for this product is described. The eye of the system is a conventional TV camera, although such devices as image dissector cameras or solid-state scanners may be used more often in the future. The analog signal from the TV camera is digitized for processing by the computer and is presented to the TV monitor to assist the operator in monitoring the system's operation. Movable stages are required when the field of view of the scanner is less than the size of the object. A minicomputer controls the movement of the stage, and communicates with the digitizer to select picture points that are to be processed. Communications with the system are maintained through a teletype or CRT terminal

Retinal nerve fiber layer measurements by scanning laser polarimetry with enhanced corneal compensation in healthy subjects.

Science.gov (United States)

Rao, Harsha L; Venkatesh, Chirravuri R; Vidyasagar, Kelli; Yadav, Ravi K; Addepalli, Uday K; Jude, Aarthi; Senthil, Sirisha; Garudadri, Chandra S

2014-12-01

To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects. In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements. One randomly selected eye of 48 subjects from the cohort underwent 3 serial scans during the same session to determine the repeatability. Age significantly influenced all RNFL measurements. RNFL measurements decreased by 1 µm for every decade increase in age. TSS affected the overall average RNFL measurement (β=-0.62, P=0.003), whereas residual anterior segment retardance affected the superior quadrant measurement (β=1.14, P=0.01). Axial length and corneal birefringence measurements did not influence RNFL measurements. Repeatability, as assessed by the coefficient of variation, ranged between 1.7% for the overall average RNFL measurement and 11.4% for th nerve fiber indicator. Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

Theory of life time measurements with the scanning electron microscope: steady state

NARCIS (Netherlands)

Berz, F.; Kuiken, H.K.

1976-01-01

A theoretical steady state analysis is given of the scanning electron microscope method of measuring bulk life time in diodes, where the plane of the junction is perpendicular to the surface. The current in the junction is obtained as a function of the beam power, the beam penetration into the

Augmentation of Quick-EXAFS measurement facility at the energy scanning EXAFS beamline at INDUS-2 SRS

Energy Technology Data Exchange (ETDEWEB)

Poswal, A. K., E-mail: poswalashwini@gmail.com; Agrawal, Ankur; Bhattachryya, D.; Jha, S. N.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai -400085 (India)

2015-06-24

In this paper implementation of Quick-EXAFS data acquisition facility at the Energy Scanning EXAFS beamline(BL-09) at INDUS-2 synchrotron source, Indore is presented. By adopting a continuous-scan mode in the Double Crystal monochromator (DCM), a high signal-to-noise ratio is maintained and the acquisition time is reduced to few seconds. The quality of spectra and repeatability is checked by measuring standards. The present mode of data acquisition would enable EXAFS measurement for in-situ studies even in fluorescence mode.

Decommissioning and dismantling: Qualification of the gamma scanning method as a certified method for radiological decontrolling measurement. Final report; Stillegung und Rueckbau: Qualifizierung des Gamma-Scanning zur Freimessung. Genehmigungspraxis. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Kirchhoff, J.; Stasch, W.P.

1998-10-01

Prior to release from the radiological supervision and control regime of the AtG (German Atomic Energy Act), nuclear facilities have to be scanned using licensed radioactivity measuring methods for providing evidence that the remaining radioactive contamination is below the legally defined limits and excludes hazards to the population, material goods, or the environment. The manually performed {alpha}/{beta} measuring methods applied so far for radiological decontrolling measurement are surface scanning methods measuring the contamination of very thin surface layers of the structures, while radioactivity in deeper layers is not necessarily detected. The gamma scanning method presented in this document is capable of scanning the structures and materials of nuclear facilities from the surface down to much deeper layers in just one measuring run. The automated scanning process at the same time offers the advantage of preventing the uncertainties possibly contributed through human factors. (orig./CB) [Deutsch] Vor der Entlassung von kerntechnischen Anlagen aus dem Geltungsbereich des AtG ist sicherzustellen, dass von der Anlage nach Freigabe aus der atomrechtlichen Ueberwachung keine Gefahren fuer Personen, Sachgueter und die Umwelt ausgehen koennen. Hierzu sind die Anlagen freizumessen, d.h. es ist durch qualifizierte Messverfahren sicherzustellen, dass festgelegte radiologische Grenzwerte unterschritten werden. Die bisherigen auf {alpha}/{beta}-Messung beruhenden Freimessverfahren (Kontaminationsmonitore) erfassen nur die Radioaktivitaet in duennsten Oberflaechenschichten. Radioaktivitaet in darunter liegenden Schichten wird nicht zwangslaeufig erfasst. Zudem erfolgen diese Messungen ausschliesslich manuell. Das Gamma-Scanning-Freimessverfahren erfasst neben der Oberflaechenschicht gleichzeitig auch tiefere Schichten. Der Nachweis der Grenzwertunterschreitung kann somit in nur einem Arbeitsgang erbracht werden. Durch automatisiertes Scannen koennte darueber hinaus

Technical Note: Potential errors in optical density measurements due to scanning side in EBT and EBT2 Gafchromic film dosimetry

International Nuclear Information System (INIS)

Desroches, Joannie; Bouchard, Hugo; Lacroix, Frederic

2010-01-01

Purpose: The purpose of this study is to determine the effect on the measured optical density of scanning on either side of a Gafchromic EBT and EBT2 film using an Epson (Epson Canada Ltd., Toronto, Ontario) 10000XL flat bed scanner. Methods: Calibration curves were constructed using EBT2 film scanned in landscape orientation in both reflection and transmission mode on an Epson 10000XL scanner. Calibration curves were also constructed using EBT film. Potential errors due to an optical density difference from scanning the film on either side (''face up'' or ''face down'') were simulated. Results: Scanning the film face up or face down on the scanner bed while keeping the film angular orientation constant affects the measured optical density when scanning in reflection mode. In contrast, no statistically significant effect was seen when scanning in transmission mode. This effect can significantly affect relative and absolute dose measurements. As an application example, the authors demonstrate potential errors of 17.8% by inverting the film scanning side on the gamma index for 3%--3 mm criteria on a head and neck intensity modulated radiotherapy plan, and errors in absolute dose measurements ranging from 10% to 35% between 2 and 5 Gy. Conclusions: Process consistency is the key to obtaining accurate and precise results in Gafchromic film dosimetry. When scanning in reflection mode, care must be taken to place the film consistently on the same side on the scanner bed.

Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

International Nuclear Information System (INIS)

Zhang Yue-Fei; Wang Li; Wei Bin; Ji Yuan; Han Xiao-Dong; Zhang Ze; Heiderhoff, R.; Geinzer, A. K.; Balk, L. J.

2012-01-01

The local thermal conductivity of polycrystalline aluminum nitride (AlN) ceramics is measured and imaged by using a scanning thermal microscope (SThM) and complementary scanning electron microscope (SEM) based techniques at room temperature. The quantitative thermal conductivity for the AlN sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3ω method. A thermal conductivity of 308 W/m·K within grains corresponding to that of high-purity single crystal AlN is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy. (condensed matter: structural, mechanical, and thermal properties)

3D velocity measurements in fluid flows using multiple exposure holography

International Nuclear Information System (INIS)

Stanislas, M.; Rodriguez, O.; Dadi, M.; Beluche, F.

1987-01-01

An account is given of multiple exposure holography's application to the measurement of velocity in fluid flows. The method is nonintrusive, and yields access to the three components of the instantaneous velocity in three-dimensional domains. These characteristics render such holographic data complementary to classical LDV. Attention is given to solutions proposed for such limitations inherent in the method as the rather lengthy acquisition time; this difficulty is presently addressed by means of an automated evaluation methodology. 12 references

Laser Scanning in Engineering Surveying: Methods of Measurement and Modeling of Structures

Directory of Open Access Journals (Sweden)

Lenda Grzegorz

2016-06-01

Full Text Available The study is devoted to the uses of laser scanning in the field of engineering surveying. It is currently one of the main trends of research which is developed at the Department of Engineering Surveying and Civil Engineering at the Faculty of Mining Surveying and Environmental Engineering of AGH University of Science and Technology in Krakow. They mainly relate to the issues associated with tower and shell structures, infrastructure of rail routes, or development of digital elevation models for a wide range of applications. These issues often require the use of a variety of scanning techniques (stationary, mobile, but the differences also regard the planning of measurement stations and methods of merging point clouds. Significant differences appear during the analysis of point clouds, especially when modeling objects. Analysis of the selected parameters is already possible basing on ad hoc measurements carried out on a point cloud. However, only the construction of three-dimensional models provides complete information about the shape of structures, allows to perform the analysis in any place and reduces the amount of the stored data. Some structures can be modeled in the form of simple axes, sections, or solids, for others it becomes necessary to create sophisticated models of surfaces, depicting local deformations. The examples selected for the study allow to assess the scope of measurement and office work for a variety of uses related to the issue set forth in the title of this study. Additionally, the latest, forward-looking technology was presented - laser scanning performed from Unmanned Aerial Vehicles (drones. Currently, it is basically in the prototype phase, but it might be expected to make a significant progress in numerous applications in the field of engineering surveying.

Impedance measurements on Au microelectrodes using controlled atmosphere high temperature scanning probe microscope

DEFF Research Database (Denmark)

Wu, Yuehua; Hansen, Karin Vels; Jacobsen, Torben

2011-01-01

High temperature impedance measurements on Au microelectrodes deposited on polished yttria stabilized zirconia (YSZ) pellets were demonstrated using a newly designed controlled atmosphere high temperature scanning probe microscope (CAHT-SPM). Probes based on Pt0.8Ir0.2 were fabricated and employed...

Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis.

Directory of Open Access Journals (Sweden)

Fan Zhang

Full Text Available Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models.Two types of dental models (intraoral scan and plaster model of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model.There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm.The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models.

Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis

Science.gov (United States)

2016-01-01

Purpose Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models. Materials and Methods Two types of dental models (intraoral scan and plaster model) of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model. Results There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm. Conclusions The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models. PMID:27304976

Measurement of conductive hearing loss in mice.

Science.gov (United States)

Qin, Zhaobing; Wood, Melissa; Rosowski, John J

2010-05-01

In order to discriminate conductive hearing loss from sensorineural impairment, quantitative measurements were used to evaluate the effect of artificial conductive pathology on distortion-product otoacoustic emissions (DPOAEs), auditory brainstem responses (ABRs) and laser-Doppler vibrometry (LDV) in mice. The conductive manipulations were created by perforating the pars flaccida of the tympanic membrane, filling or partially filling the middle-ear cavity with saline, fixing the ossicular chain, and interrupting the incudo-stapedial joint. In the saline-filled and ossicular-fixation groups, averaged DPOAE thresholds increased relative to the control state by 20-36 and 25-39 dB, respectively with the largest threshold shifts occurring at frequencies less than 20kHz, while averaged ABR thresholds increased 12-19 and 12-25 dB, respectively without the predominant low-frequency effect. Both DPOAE and ABR thresholds were elevated by less than 10 dB in the half-filled saline condition; no significant change was observed after pars flaccida perforation. Conductive pathology generally produced a change in DPOAE threshold in dB that was 1.5-2.5 times larger than the ABR threshold change at frequencies less than 30 kHz; the changes in the two thresholds were nearly equal at the highest frequencies. While mild conductive pathology (ABR threshold shifts of conductive hearing losses (ABR threshold shifts >10 dB) were associated with significant deceases in DPOAE growth rate. Our LDV measurements are consistent with others and suggest that measurements of umbo velocity are not an accurate indicator of conductive hearing loss produced by ossicular lesions in mice. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Identification of damage in plates using full-field measurement with a continuously scanning laser Doppler vibrometer system

Science.gov (United States)

Chen, Da-Ming; Xu, Y. F.; Zhu, W. D.

2018-05-01

An effective and reliable damage identification method for plates with a continuously scanning laser Doppler vibrometer (CSLDV) system is proposed. A new constant-speed scan algorithm is proposed to create a two-dimensional (2D) scan trajectory and automatically scan a whole plate surface. Full-field measurement of the plate can be achieved by applying the algorithm to the CSLDV system. Based on the new scan algorithm, the demodulation method is extended from one dimension for beams to two dimensions for plates to obtain a full-field operating deflection shape (ODS) of the plate from velocity response measured by the CSLDV system. The full-field ODS of an associated undamaged plate is obtained by using polynomials with proper orders to fit the corresponding full-field ODS from the demodulation method. A curvature damage index (CDI) using differences between curvatures of ODSs (CODSs) associated with ODSs that are obtained by the demodulation method and the polynomial fit is proposed to identify damage. An auxiliary CDI obtained by averaging CDIs at different excitation frequencies is defined to further assist damage identification. An experiment of an aluminum plate with damage in the form of 10.5% thickness reduction in a damage area of 0.86% of the whole scan area is conducted to investigate the proposed method. Six frequencies close to natural frequencies of the plate and one randomly selected frequency are used as sinusoidal excitation frequencies. Two 2D scan trajectories, i.e., a horizontally moving 2D scan trajectory and a vertically moving 2D scan trajectory, are used to obtain ODSs, CODSs, and CDIs of the plate. The damage is successfully identified near areas with consistently high values of CDIs at different excitation frequencies along the two 2D scan trajectories; the damage area is also identified by auxiliary CDIs.

Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

Science.gov (United States)

Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

2013-11-01

To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Experimental comparison of the optical measurements of a cross-flow in a rod bundle with mixing vanes

International Nuclear Information System (INIS)

Chang, Seok Kyu; Choo, Yeon Jun; Kim, Bok Deuk; Song, Chul Hwa

2008-01-01

The lateral crossflow on subchannels in a rod bundle array was investigated to understand the flow characteristics related to the mixing vane types on a spacer grid by using the PIV technique. For more measurement resolutions, a 5x5 rod bundle was fabricated a 2.6 times larger than the real rod bundle size in a pressurized water reactor. A rod-embedded optic array was specially designed and used for the illumination of the inner subchannels. The crossflow field in a subchannel was characterized by the type and the arrangement of the mixing vanes. At a near downstream location from the spacer grid (z/D h =1) in the case of the split type, a couple of small vortices were generated diagonally in a subchannel. On the other hand, in the case of the swirl type, there was a large elliptic vortex generated in the center of a subchannel. The measurement results were compared with the experimental results which had been performed with the LDV technique at the same test facility. The magnitudes of the flow velocity and the vorticity in PIV results were less than those in LDV measurement results. It was shown that the instantaneous flow fields in a subchannel frequently have quite different shapes from the averaged one

Strain fields around dislocation arrays in a Σ9 silicon bicrystal measured by scanning transmission electron microscopy

Science.gov (United States)

Couillard, Martin; Radtke, Guillaume; Botton, Gianluigi A.

2013-04-01

Strain fields around grain boundary dislocations are measured by applying geometric phase analysis on atomic resolution images obtained from multiple fast acquisitions in scanning transmission electron microscopy. Maps of lattice distortions in silicon introduced by an array of pure edge dislocations located at a Σ9(122) grain boundary are compared with the predictions from isotropic elastic theory, and the atomic structure of dislocation cores is deduced from images displaying all the atomic columns. For strain measurements, reducing the acquisition time is found to significantly decrease the effects of instabilities on the high-resolution images. Contributions from scanning artefacts are also diminished by summing multiple images following a cross-correlation alignment procedure. Combined with the sub-Ångström resolution obtained with an aberration corrector, and the stable dedicated microscope's environment, therapid acquisition method provides the measurements of atomic displacements with accuracy below 10 pm. Finally, the advantages of combining strain measurements with the collection of various analytical signals in a scanning transmission electron microscope are discussed.

Comparison of corneal measurements in keratoconic eyes using rotating Scheimpflug camera and scanning-slit topography

Directory of Open Access Journals (Sweden)

Mohammad Naderan

2015-04-01

Full Text Available AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera (Pentacam and Scanning-slit topography (Orbscan IIz in keratoconic eyes. METHODS: A total of 121 patients, 71 males (58.7% and 50 females (41.3% (214 eyes with the diagnosis of keratoconus (KC were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness (CCT, thinnest corneal thickness (TCT, anterior chamber depth (ACD, and pupil diameter (PD were measured by a single examiner using successive instrumentation by Pentacam and Orbscan. RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD (3.46±0.40 mm vs. 3.38±0.33 mm, P=0.019 and PD (4.97±1.26 mm vs 4.08±1.19 mm, P<0.001 significantly larger than rotating Scheimpflug camera. The two devices made similar measurements for CCT (95% CI: -2.94 to 5.06, P=0.602. However, the mean difference for TCT was -6.28 (95% CI: -10.51 to -2.06, P=0.004 showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm (95% CI: 0.04 to 0.12, P<0.001 with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam (95% CI: 0.68 to 1.08, P<0.001. CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotating Scheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.

Do physical examination and CT-scan measures of femoral neck anteversion and tibial torsion relate to each other?

Science.gov (United States)

Sangeux, Morgan; Mahy, Jessica; Graham, H Kerr

2014-01-01

Informed clinical decision making for femoral and/or tibial de-rotation osteotomies requires accurate measurement of patient function through gait analysis and anatomy through physical examination of bony torsions. Validity of gait analysis has been extensively studied; however, controversy remains regarding the accuracy of physical examination measurements of femoral and tibial torsion. Comparison between CT-scans and physical examination measurements of femoral neck anteversion (FNA) and external tibial torsion (ETT) were retrospectively obtained for 98 (FNA) and 64 (ETT) patients who attended a tertiary hospital for instrumented gait analysis between 2007 and 2010. The physical examination methods studied for femoral neck anteversion were the trochanteric prominence angle test (TPAT) and the maximum hip rotation arc midpoint (Arc midpoint) and for external tibial torsion the transmalleolar axis (TMA). Results showed that all physical examination measurements statistically differed to the CT-scans (bias(standard deviation): -2(14) for TPAT, -10(12) for Arc midpoint and -16(9) for TMA). Bland and Altman plots showed that method disagreements increased with increasing bony torsions in all cases but notably for TPAT. Regression analysis showed that only TMA and CT-scan measurement of external tibial torsion demonstrated good (R(2)=57%) correlation. Correlations for both TPAT (R(2)=14%) and Arc midpoint (R(2)=39%) with CT-scan measurements of FNA were limited. We conclude that physical examination should be considered as screening techniques rather than definitive measurement methods for FNA and ETT. Further research is required to develop more accurate measurement methods to accompany instrumented gait analysis. Copyright © 2013. Published by Elsevier B.V.

Influence of blockage effect on measurement by vane anemometers

Directory of Open Access Journals (Sweden)

Sluse Jan

2017-01-01

Full Text Available The article deals with influence of blockage effect caused by vane anemometer in the wind tunnel by measurement via this anemometer. The influences will be represented by correction coefficient. The first part of this article is focused on the design of the impeller of vane anemometers. The impellers are printed on 3D printer with variable parameters. The anemometer is fixed in an open section of the wind tunnel with closed loop and the velocity profile is measured by Laser Doppler velocimetry (LDV in front and behind it for all impellers. The experimental data are compared with the numerical simulation in OpenFOAM. The results are correction coefficients.

Special Properties of Coherence Scanning Interferometers for large Measurement Volumes

International Nuclear Information System (INIS)

Bauer, W

2011-01-01

In contrast to many other optical methods the uncertainty of Coherence Scanning Interferometer (CSI) in vertical direction is independent from the field of view. Therefore CSIs are ideal instruments for measuring 3D-profiles of larger areas (36x28mm 2 , e.g.) with high precision. This is of advantage for the determination of form parameters like flatness, parallelism and steps heights within a short time. In addition, using a telecentric beam path allows measurements of deep lying surfaces (<70mm) and the determination of form parameters with large step-heights. The lateral and spatial resolution, however, are reduced. In this presentation different metrological characteristics together with their potential errors are analyzed for large-scale measuring CSIs. Therefore these instruments are ideal tools in quality control for good/bad selections, e.g. The consequences for the practical use in industry and for standardization are discussed by examples of workpieces of automotive suppliers or from the steel industry.

Scatter measurement and correction method for cone-beam CT based on single grating scan

Science.gov (United States)

Huang, Kuidong; Shi, Wenlong; Wang, Xinyu; Dong, Yin; Chang, Taoqi; Zhang, Hua; Zhang, Dinghua

2017-06-01

In cone-beam computed tomography (CBCT) systems based on flat-panel detector imaging, the presence of scatter significantly reduces the quality of slices. Based on the concept of collimation, this paper presents a scatter measurement and correction method based on single grating scan. First, according to the characteristics of CBCT imaging, the scan method using single grating and the design requirements of the grating are analyzed and figured out. Second, by analyzing the composition of object projection images and object-and-grating projection images, the processing method for the scatter image at single projection angle is proposed. In addition, to avoid additional scan, this paper proposes an angle interpolation method of scatter images to reduce scan cost. Finally, the experimental results show that the scatter images obtained by this method are accurate and reliable, and the effect of scatter correction is obvious. When the additional object-and-grating projection images are collected and interpolated at intervals of 30 deg, the scatter correction error of slices can still be controlled within 3%.

A New Ka-Band Scanning Radar Facility: Polarimetric and Doppler Spectra Measurements of Snow Events

Science.gov (United States)

Oue, M.; Kollias, P.; Luke, E. P.; Mead, J.

2017-12-01

Polarimetric radar analyses offer the capability of identification of ice hydrometeor species as well as their spatial distributions. In addition to polarimetric parameter observations, Doppler spectra measurements offer unique insights into ice particle properties according to particle fall velocities. In particular, millimeter-wavelength radar Doppler spectra can reveal supercooled liquid cloud droplets embedded in ice precipitation clouds. A Ka-band scanning polarimetric radar, named KASPR, was installed in an observation facility at Stony Brook University, located 22 km west of the KOKX NEXRAD radar at Upton, NY. The KASPR can measure Doppler spectra and full polarimetric variables, including radar reflectivity, differential reflectivity (ZDR), differential phase (φDP), specific differential phase (KDP), correlation coefficient (ρhv), and linear depolarization ratio (LDR). The facility also includes a micro-rain radar and a microwave radiometer capable of measuring reflectivity profiles and integrated liquid water path, respectively. The instruments collected initial datasets during two snowstorm events and two snow shower events in March 2017. The radar scan strategy was a combination of PPI scans at 4 elevation angles (10, 20, 45, and 60°) and RHI scans in polarimetry mode, and zenith pointing with Doppler spectra collection. During the snowstorm events the radar observed relatively larger ZDR (1-1.5 dB) and enhanced KDP (1-2 ° km-1) at heights corresponding to a plate/dendrite crystal growth regime. The Doppler spectra showed that slower-falling particles ( 1 m s-1). The weakly increased ZDR could be produced by large, faster falling particles such as quasi-spherical aggregates, while the enhanced KDP could be produced by highly-oriented oblate, slowly-falling particles. Below 2 km altitude, measurements of dual wavelength ratio (DWR) based on Ka and S-band reflectivities from the KASPR and NEXRAD radars were available. Larger DWR (>10 dB) suggested

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

International Nuclear Information System (INIS)

Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat; Sriwilas, Patiyut; Midtboe, Marit

2017-01-01

The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm"2) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

Energy Technology Data Exchange (ETDEWEB)

Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat [Dept. of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand); Sriwilas, Patiyut [Dept. of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok (Thailand); Midtboe, Marit [Dept. of Clinical Dentistry - Orthodontics, Faculty of Medicine and Dentistry, University of Bergen, Bergen (Norway)

2017-06-15

The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm{sup 2}) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

Measurements of CO2 Concentration and Wind Profiles with A Scanning 1.6μm DIAL

Science.gov (United States)

Abo, M.; Shibata, Y.; Nagasawa, C.; Nagai, T.; Sakai, T.; Tsukamoto, M.

2012-12-01

Horizontal carbon dioxide (CO2) distribution and wind profiles are important information for understanding of the regional sink and source of CO2. The differential absorption lidar (DIAL) and the Doppler lidar with the range resolution is expected to bring several advantages over passive measurements. We have developed a new scanning 1.6μm DIAL and incoherent Doppler lidar system to perform simultaniously measurements of CO2 concentration and wind speed profiles in the atmosphere. The 1.6μm DIAL and Doppler lidar system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd:YAG laser with high repetition rate (500 Hz). The receiving optics include the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detct Doppler shift, and a 25 cm telescope[1][2]. Laser beam is transmitted coaxially and motorized scanning mirror system can scan the laser beam and field of view 0-360deg horizontally and 0-52deg vertically. We report the results of vertical CO2 scanning measurenents and vertical wind profiles. The scanning elevation angles were from 12deg to 24deg with angular step of 4deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m altitude resolution. We also obtained vertical wind vector profiles by measuring line-of-sight wind profiles at two azimuth angles with a fixed elevation angle 52deg. Vertical wind vector profiles were obtained up to 5 km altitude with 1 km altitude rasolution. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. References [1] L. B. Vann, et al., "Narrowband fiber-optic phase-shifted Fabry-Perot Bragg grating filters for atmospheric water vapor lidar measurements", Appl. Opt., 44, pp. 7371-7377 (2005). [2] Y. Shibata, et al., "1.5μm incoherent Doppler lidar using a FBG filter", Proceedings

Optimization of the imaging response of scanning microwave microscopy measurements

Energy Technology Data Exchange (ETDEWEB)

Sardi, G. M.; Lucibello, A.; Proietti, E.; Marcelli, R., E-mail: romolo.marcelli@imm.cnr.it [National Research Council, Institute for Microelectronics and Microsystems, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Kasper, M.; Gramse, G. [Biophysics Institute, Johannes Kepler University, Gruberstrasse 40, 4020 Linz (Austria); Kienberger, F. [Keysight Technologies Austria GmbH, Gruberstrasse 40, 4020 Linz (Austria)

2015-07-20

In this work, we present the analytical modeling and preliminary experimental results for the choice of the optimal frequencies when performing amplitude and phase measurements with a scanning microwave microscope. In particular, the analysis is related to the reflection mode operation of the instrument, i.e., the acquisition of the complex reflection coefficient data, usually referred as S{sub 11}. The studied configuration is composed of an atomic force microscope with a microwave matched nanometric cantilever probe tip, connected by a λ/2 coaxial cable resonator to a vector network analyzer. The set-up is provided by Keysight Technologies. As a peculiar result, the optimal frequencies, where the maximum sensitivity is achieved, are different for the amplitude and for the phase signals. The analysis is focused on measurements of dielectric samples, like semiconductor devices, textile pieces, and biological specimens.

Use of FET in automatic scanning of measurements using thermocouples and self-powered neutron detectors

International Nuclear Information System (INIS)

Plaige, Yves.

1977-01-01

Advantages lying in using FET switches in the relays of multiplexing systems are shown with two examples of application. Their performance as regard fast reliable operation are used in temperature measurement scanning inside nuclear reactors. As for current measurements using self-powered neutron detectors, the weak leakage currents of said switches ( [fr

A novel fast-scanning microwave heterodyne radiometer system for electron cyclotron emission measurements in the HT-7 superconducting tokamak

International Nuclear Information System (INIS)

Zhang, S.Y.; Wan, Y.X.; Xie, J.K.; Luo, J.R.; Li, J.G.; Kuang, G.L.; Gao, X.; Zhang, X.D.; Wan, B.N.; Wang, K.J.; Mao, J.S.; Gong, X.Z.; Qin, P.J.

2000-01-01

Two sets of fast-scanning microwave heterodyne radiometer receiver systems employing backward-wave oscillators in the 78-118 GHz and 118-178 GHz ranges were developed for electron cyclotron emission measurements (ECE) on the HT-7 superconducting tokamak. The double-sideband radiometer in the 78-118 GHz range measures 16 ECE frequency points with a scanning period of 0.65 ms. The novel design of the 2 mm fast-scanning heterodyne radiometer in the 118-178 GHz range enables the unique system to measure 48 ECE frequency points in 0.65 ms periodically. The plasma profile consistency in reproducible ohmic plasmas was used to relatively calibrate each channel by changing the toroidal magnetic field shot-by-shot. The absolute temperature value was obtained by a comparison with the results from the soft x-ray pulse height analysis measurements and Thomson scattering system. A preliminary temperature profile measurement result in pellet injection plasma is presented. (author)

Colour measurements of pigmented rice grain using flatbed scanning and image analysis

Science.gov (United States)

Kaisaat, Khotchakorn; Keawdonree, Nuttapong; Chomkokard, Sakchai; Jinuntuya, Noparit; Pattanasiri, Busara

2017-09-01

Recently, the National Bureau of Agricultural Commodity and Food Standards (ACFS) have drafted a manual of Thai colour rice standards. However, there are no quantitative descriptions of rice colour and its measurement method. These drawbacks might lead to misunderstanding for people who use the manual. In this work, we proposed an inexpensive method, using flatbed scanning together with image analysis, to quantitatively measure rice colour and colour uniformity. To demonstrate its general applicability for colour differentiation of rice, we applied it to different kinds of pigmented rice, including Riceberry rice with and without uniform colour and Chinese black rice.

Research on Radar Cross Section Measurement Based on Near-field Imaging of Cylindrical Scanning

Directory of Open Access Journals (Sweden)

Xing Shu-guang

2015-04-01

Full Text Available A new method of Radar Cross Section (RCS measurement based on near-field imaging of cylindrical scanning surface is proposed. The method is based on the core assumption that the target consists of ideal isotropic scattered centers. Three-dimensional radar scattered images are obtained by using the proposed method, and then to obtain the RCS of the target, the scattered far field is calculated by summing the fields generated by the equivalent scattered centers. Not only three dimensional radar reflectivity images but also the RCS of targets in certain three dimensional angle areas can be obtained. Compared with circular scanning that can only obtain twodimensional radar reflectivity images and RCS results in two-dimensional angle areas, cylindrical scanning can provide more information about the scattering properties of the targets. The method has strong practicability and its validity is verified by simulations.

The measurements of water flow rates in the straight microchannel based on the scanning micro-PIV technique

Science.gov (United States)

Wang, H. L.; Han, W.; Xu, M.

2011-12-01

Measurement of the water flow rate in microchannel has been one of the hottest points in the applications of microfluidics, medical, biological, chemical analyses and so on. In this study, the scanning microscale particle image velocimetry (scanning micro-PIV) technique is used for the measurements of water flow rates in a straight microchannel of 200μm width and 60μm depth under the standard flow rates ranging from 2.481μL/min to 8.269μL/min. The main effort of this measurement technique is to obtain three-dimensional velocity distribution on the cross sections of microchannel by measuring velocities of the different fluid layers along the out-of-plane direction in the microchannel, so the water flow rates can be evaluated from the discrete surface integral of velocities on the cross section. At the same time, the three-dimensional velocity fields in the measured microchannel are simulated numerically using the FLUENT software in order to verify the velocity accuracy of measurement results. The results show that the experimental values of flow rates are well consistent to the standard flow rates input by the syringe pump and the compared results between numerical simulation and experiment are consistent fundamentally. This study indicates that the micro-flow rate evaluated from three-dimensional velocity by the scanning micro-PIV technique is a promising method for the micro-flow rate research.

Wind field re-construction of 3D Wake measurements from a turbine-installed scanning lidar

DEFF Research Database (Denmark)

Mikkelsen, Torben Krogh; Herges, Tommy; Astrup, Poul

High-resolution wake flow measurements obtained from a turbine-mounted scanning lidar have been obtained from 1D to 5D behind a V27 test turbine. The measured line-of-sight projected wind speeds have, in connection with a fast CFD wind field reconstruction model, been used to generate 3D wind fie...

Analysis of 3D Scan Measurement Distribution with Application to a Multi-Beam Lidar on a Rotating Platform.

Science.gov (United States)

Morales, Jesús; Plaza-Leiva, Victoria; Mandow, Anthony; Gomez-Ruiz, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

2018-01-30

Multi-beam lidar (MBL) rangefinders are becoming increasingly compact, light, and accessible 3D sensors, but they offer limited vertical resolution and field of view. The addition of a degree-of-freedom to build a rotating multi-beam lidar (RMBL) has the potential to become a common solution for affordable rapid full-3D high resolution scans. However, the overlapping of multiple-beams caused by rotation yields scanning patterns that are more complex than in rotating single beam lidar (RSBL). In this paper, we propose a simulation-based methodology to analyze 3D scanning patterns which is applied to investigate the scan measurement distribution produced by the RMBL configuration. With this purpose, novel contributions include: (i) the adaption of a recent spherical reformulation of Ripley's K function to assess 3D sensor data distribution on a hollow sphere simulation; (ii) a comparison, both qualitative and quantitative, between scan patterns produced by an ideal RMBL based on a Velodyne VLP-16 (Puck) and those of other 3D scan alternatives (i.e., rotating 2D lidar and MBL); and (iii) a new RMBL implementation consisting of a portable tilting platform for VLP-16 scanners, which is presented as a case study for measurement distribution analysis as well as for the discussion of actual scans from representative environments. Results indicate that despite the particular sampling patterns given by a RMBL, its homogeneity even improves that of an equivalent RSBL.

Analysis of 3D Scan Measurement Distribution with Application to a Multi-Beam Lidar on a Rotating Platform

Science.gov (United States)

Plaza-Leiva, Victoria; Serón, Javier

2018-01-01

Multi-beam lidar (MBL) rangefinders are becoming increasingly compact, light, and accessible 3D sensors, but they offer limited vertical resolution and field of view. The addition of a degree-of-freedom to build a rotating multi-beam lidar (RMBL) has the potential to become a common solution for affordable rapid full-3D high resolution scans. However, the overlapping of multiple-beams caused by rotation yields scanning patterns that are more complex than in rotating single beam lidar (RSBL). In this paper, we propose a simulation-based methodology to analyze 3D scanning patterns which is applied to investigate the scan measurement distribution produced by the RMBL configuration. With this purpose, novel contributions include: (i) the adaption of a recent spherical reformulation of Ripley’s K function to assess 3D sensor data distribution on a hollow sphere simulation; (ii) a comparison, both qualitative and quantitative, between scan patterns produced by an ideal RMBL based on a Velodyne VLP-16 (Puck) and those of other 3D scan alternatives (i.e., rotating 2D lidar and MBL); and (iii) a new RMBL implementation consisting of a portable tilting platform for VLP-16 scanners, which is presented as a case study for measurement distribution analysis as well as for the discussion of actual scans from representative environments. Results indicate that despite the particular sampling patterns given by a RMBL, its homogeneity even improves that of an equivalent RSBL. PMID:29385705

Developing optimized CT scan protocols: Phantom measurements of image quality

International Nuclear Information System (INIS)

Zarb, Francis; Rainford, Louise; McEntee, Mark F.

2011-01-01

Purpose: The increasing frequency of computerized tomography (CT) examinations is well documented, leading to concern about potential radiation risks for patients. However, the consequences of not performing the CT examination and missing injuries and disease are potentially serious, impacting upon correct patient management. The ALARA principle of dose optimization must be employed for all justified CT examinations. Dose indicators displayed on the CT console as either CT dose index (CTDI) and/or dose length product (DLP), are used to indicate dose and can quantify improvements achieved through optimization. Key scan parameters contributing to dose have been identified in previous literature and in previous work by our group. The aim of this study was to optimize the scan parameters of mA; kV and pitch, whilst maintaining image quality and reducing dose. This research was conducted using psychophysical image quality measurements on a CT quality assurance (QA) phantom establishing the impact of dose optimization on image quality parameters. Method: Current CT scan parameters for head (posterior fossa and cerebrum), abdomen and chest examinations were collected from 57% of CT suites available nationally in Malta (n = 4). Current scan protocols were used to image a Catphan 600 CT QA phantom whereby image quality was assessed. Each scan parameter: mA; kV and pitch were systematically reduced until the contrast resolution (CR), spatial resolution (SR) and noise were significantly lowered. The Catphan 600 images, produced by the range of protocols, were evaluated by 2 expert observers assessing CR, SR and noise. The protocol considered as the optimization threshold was just above the setting that resulted in a significant reduction in CR and noise but not affecting SR at the 95% confidence interval. Results: The limit of optimization threshold was determined for each CT suite. Employing optimized parameters, CTDI and DLP were both significantly reduced (p ≤ 0.001) by

A simple program to measure and analyse tree rings using Excel, R and SigmaScan

Science.gov (United States)

Hietz, Peter

2011-01-01

I present a new software that links a program for image analysis (SigmaScan), one for spreadsheets (Excel) and one for statistical analysis (R) for applications of tree-ring analysis. The first macro measures ring width marked by the user on scanned images, stores raw and detrended data in Excel and calculates the distance to the pith and inter-series correlations. A second macro measures darkness along a defined path to identify latewood–earlywood transition in conifers, and a third shows the potential for automatic detection of boundaries. Written in Visual Basic for Applications, the code makes use of the advantages of existing programs and is consequently very economic and relatively simple to adjust to the requirements of specific projects or to expand making use of already available code. PMID:26109835

A simple program to measure and analyse tree rings using Excel, R and SigmaScan.

Science.gov (United States)

Hietz, Peter

I present a new software that links a program for image analysis (SigmaScan), one for spreadsheets (Excel) and one for statistical analysis (R) for applications of tree-ring analysis. The first macro measures ring width marked by the user on scanned images, stores raw and detrended data in Excel and calculates the distance to the pith and inter-series correlations. A second macro measures darkness along a defined path to identify latewood-earlywood transition in conifers, and a third shows the potential for automatic detection of boundaries. Written in Visual Basic for Applications, the code makes use of the advantages of existing programs and is consequently very economic and relatively simple to adjust to the requirements of specific projects or to expand making use of already available code.

Stoichiometrical trends in differential scanning calorimetry measurements on phase-change materials

Energy Technology Data Exchange (ETDEWEB)

Klein, Michael; Linn, Malte; Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, Aachen (Germany)

2009-07-01

Phase-change materials are alloys which can be rapidly switched between two metastable states, the amorphous and the crystalline phase. At the same time they show pronounced contrast in their electrical and optical properties. They are widely used as the functional layer in rewritable optical discs. Prototypes of electrical devices employing phase change materials as non-volatile memory are already entering the market. Here we present calorimetric measurements, mainly on ternary Ge-Sb-Te alloys. Scratched-off thin film samples were heated in a differential scanning calorimeter to measure the transition from as-deposited amorphous to metastable crystalline phase and finally to the stable crystalline phase. The different transition temperatures will be analysed as a function of stoichiometry in order to improve the understanding of their interconnection.

Development of a scanning tunneling potentiometry system for measurement of electronic transport at short length scales

Science.gov (United States)

Rozler, Michael

It is clear that complete understanding of macroscopic properties of materials is impossible without a thorough knowledge of behavior at the smallest length scales. While the past 25 years have witnessed major advances in a variety of techniques that probe the nanoscale properties of matter, electrical transport measurements -- the heart of condensed matter research -- have lagged behind, never progressing beyond bulk measurements. This thesis describes a scanning tunneling potentiometry (STP) system developed to simultaneously map the transport-related electrochemical potential distribution of a biased sample along with its surface topography, extending electronic transport measurements to the nanoscale. Combining a novel sample biasing technique with a continuous current-nulling feedback scheme pushes the noise performance of the measurement to its fundamental limit - the Johnson noise of the STM tunnel junction. The resulting 130 nV voltage sensitivity allows us to spatially resolve local potentials at scales down to 2 nm, while maintaining atomic scale STM imaging, all at scan sizes of up to 15 microns. A mm-range two-dimensional coarse positioning stage and the ability to operate from liquid helium to room temperature with a fast turn-around time greatly expand the versatility of the instrument. Use of carefully selected model materials, combined with excellent topographic and voltage resolution has allowed us to distinguish measurement artifacts caused by surface roughness from true potentiometric features, a major problem in previous STP measurements. The measurements demonstrate that STP can produce physically meaningful results for homogeneous transport as well as non-uniform conduction dominated by material microstructures. Measurements of several physically interesting materials systems are presented as well, revealing new behaviors at the smallest length sales. The results establish scanning tunneling potentiometry as a useful tool for physics and

Abrasion of 6 dentifrices measured by vertical scanning interference microscopy.

Science.gov (United States)

Pascaretti-Grizon, Florence; Mabilleau, Guillaume; Chappard, Daniel

2013-01-01

The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials.

Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires; Aufbau einer Vierspitzen-Rastertunnelmikroskop/Rasterelektronenmikroskop-Kombination und Leitfaehigkeitsmessungen an Silizid Nanodraehten

Energy Technology Data Exchange (ETDEWEB)

Zubkov, Evgeniy

2013-09-01

In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

DEFF Research Database (Denmark)

Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

2012-01-01

lung density measurements, i.e. densitometry. Methods – In a pilot study 60 CT scans were selected from a sample of 3980 CT scans from The Danish Lung Cancer Screening Trial (DLCST). The amount of emphysema in these scans was scored independently by two observers, who were blinded regarding clinical...... information. The lung was segmented automatically by in-house developed computer software, and the percentage of pixels below -950 HU was used as a surrogate marker for emphysema. The observer variability, as well as the correlation with the lung density measurements, was analysed using Spearman’s rank...... in emphysema grading. However, the agreement with the CT lung density measurement was poor, indicating that the two types of evaluation represent different aspects of emphysema. Most likely, they should be seen as complementary rather than competitive evaluations. Future comparison with physiological tests...

Optical Flow-Field Techniques Used for Measurements in High-Speed Centrifugal Compressors

Science.gov (United States)

Skoch, Gary J.

1999-01-01

The overall performance of a centrifugal compressor depends on the performance of the impeller and diffuser as well as on the interactions occurring between these components. Accurate measurements of the flow fields in each component are needed to develop computational models that can be used in compressor design codes. These measurements must be made simultaneously over an area that covers both components so that researchers can understand the interactions occurring between the two components. Optical measurement techniques are being used at the NASA Lewis Research Center to measure the velocity fields present in both the impeller and diffuser of a 4:1 pressure ratio centrifugal compressor operating at several conditions ranging from design flow to surge. Laser Doppler Velocimetry (LDV) was used to measure the intrablade flows present in the impeller, and the results were compared with analyses obtained from two three-dimensional viscous codes. The development of a region of low throughflow velocity fluid within this high-speed impeller was examined and compared with a similar region first observed in a large low-speed centrifugal impeller at Lewis. Particle Image Velocimetry (PIV) is a relatively new technique that has been applied to measuring the diffuser flow fields. PIV can collect data rapidly in the diffuser while avoiding the light-reflection problems that are often encountered when LDV is used. The Particle Image Velocimeter employs a sheet of pulsed laser light that is introduced into the diffuser in a quasi-radial direction through an optical probe inserted near the diffuser discharge. The light sheet is positioned such that its centerline is parallel to the hub and shroud surfaces and such that it is parallel to the diffuser vane, thereby avoiding reflections from the solid surfaces. Seed particles small enough to follow the diffuser flow are introduced into the compressor at an upstream location. A high-speed charge-coupled discharge (CCD) camera is

ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction

International Nuclear Information System (INIS)

Wu Yan; Shannon, Mark A.

2006-01-01

The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium/gap/gold and platinum-iridium/gap/thermal oxide/silicon are discussed

Particle image velocimetry measurements of the flow in the converging region of two parallel jets

Energy Technology Data Exchange (ETDEWEB)

Wang, Huhu, E-mail: huhuwang@tamu.edu; Lee, Saya, E-mail: sayalee@tamu.edu; Hassan, Yassin A., E-mail: y-hassan@tamu.edu

2016-09-15

Highlights: • The flow behaviors in the converging region were non-intrusively investigated using PIV. • The PIV results using two measuring scales and LDV data matched very well. • Significant momentum transfer was observed in the merging region right after the merging point. • Instantaneous vector field revealed characteristic interacting patterns of the jets. - Abstract: The interaction between parallel jets plays a critical role in determining the characteristics of the momentum and heat transfer in the flow. Specifically for next generation VHTR, the output temperature will be about 900 °C, and any thermal oscillations will create safety issues. The mixing variations of the coolants in the reactor core may influence these power oscillations. Numerous numerical tools such as computational fluid dynamics (CFD) simulations have been used to support the reactor design. The validation of CFD method is important to ensure the fidelity of the calculations. This requires high-fidelity, qualified benchmark data. Particle image velocimetry (PIV), a non-intrusive measuring technique, was used to provide benchmark data for resolving a simultaneous flow field in the converging region of two submerged parallel jets issued from rectangular channels. The jets studied in this work had an equal discharge velocity at room temperature. The turbulent characteristics including the distributions of mean velocities, turbulence intensities, Reynolds stresses and z-component vorticity were studied. The streamwise mean velocity measured by PIV and LDV were compared, and they agreed very well.

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes.

Science.gov (United States)

Yakubova, Galina; Kavetskiy, Aleksandr; Prior, Stephen A; Torbert, H Allen

2017-08-24

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m 2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is >1.5 carbon weight % (standard deviation ± 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

Automated measurement of uptake in cerebellum, liver, and aortic arch in full-body FDG PET/CT scans.

Science.gov (United States)

Bauer, Christian; Sun, Shanhui; Sun, Wenqing; Otis, Justin; Wallace, Audrey; Smith, Brian J; Sunderland, John J; Graham, Michael M; Sonka, Milan; Buatti, John M; Beichel, Reinhard R

2012-06-01

The purpose of this work was to develop and validate fully automated methods for uptake measurement of cerebellum, liver, and aortic arch in full-body PET/CT scans. Such measurements are of interest in the context of uptake normalization for quantitative assessment of metabolic activity and/or automated image quality control. Cerebellum, liver, and aortic arch regions were segmented with different automated approaches. Cerebella were segmented in PET volumes by means of a robust active shape model (ASM) based method. For liver segmentation, a largest possible hyperellipsoid was fitted to the liver in PET scans. The aortic arch was first segmented in CT images of a PET/CT scan by a tubular structure analysis approach, and the segmented result was then mapped to the corresponding PET scan. For each of the segmented structures, the average standardized uptake value (SUV) was calculated. To generate an independent reference standard for method validation, expert image analysts were asked to segment several cross sections of each of the three structures in 134 F-18 fluorodeoxyglucose (FDG) PET/CT scans. For each case, the true average SUV was estimated by utilizing statistical models and served as the independent reference standard. For automated aorta and liver SUV measurements, no statistically significant scale or shift differences were observed between automated results and the independent standard. In the case of the cerebellum, the scale and shift were not significantly different, if measured in the same cross sections that were utilized for generating the reference. In contrast, automated results were scaled 5% lower on average although not shifted, if FDG uptake was calculated from the whole segmented cerebellum volume. The estimated reduction in total SUV measurement error ranged between 54.7% and 99.2%, and the reduction was found to be statistically significant for cerebellum and aortic arch. With the proposed methods, the authors have demonstrated that

Measurement of third-order nonlinear susceptibility tensor in InP using extended Z-scan technique with elliptical polarization

Science.gov (United States)

Oishi, Masaki; Shinozaki, Tomohisa; Hara, Hikaru; Yamamoto, Kazunuki; Matsusue, Toshio; Bando, Hiroyuki

2018-05-01

The elliptical polarization dependence of the two-photon absorption coefficient β in InP has been measured by the extended Z-scan technique for thick materials in the wavelength range from 1640 to 1800 nm. The analytical formula of the Z-scan technique has been extended with consideration of multiple reflections. The Z-scan results have been fitted very well by the formula and β has been evaluated accurately. The three independent elements of the third-order nonlinear susceptibility tensor in InP have also been determined accurately from the elliptical polarization dependence of β.

The along track scanning radiometer - an analysis of coincident ship and satellite measurements

Science.gov (United States)

Barton, I. J.; Prata, A. J.; Llewellyn-Jones, D. T.

1993-05-01

Following the successful launch of the ERS-1 satellite in July 1991 we have undertaken several geophysical validation cruises in the Coral Sea. The prime aim of these cruises was to compare the sea surface temperature (SST) derived from the Along Track Scanning Radiometer (ATSR) with that measured using precision radiometers mounted on the ships. On most occasions when simultaneous satellite and ship measurements were taken we also launched a radiosonde from one of the research vessels. The results suggest that the ATSR is able to measure the ``skin'' temperature of the sea surface with an accuracy suitable for climate research applications. A case study comparison between the AVHRR and ATSR SST products will also be presented.

Sequential multipoint motion of the tympanic membrane measured by laser Doppler vibrometry: preliminary results for normal tympanic membrane.

Science.gov (United States)

Kunimoto, Yasuomi; Hasegawa, Kensaku; Arii, Shiro; Kataoka, Hideyuki; Yazama, Hiroaki; Kuya, Junko; Kitano, Hiroya

2014-04-01

Numerous studies have reported sound-induced motion of the tympanic membrane (TM). To demonstrate sequential motion characteristics of the entire TM by noncontact laser Doppler vibrometry (LDV), we have investigated multipoint TM measurement. A laser Doppler vibrometer was mounted on a surgical microscope. The velocity was measured at 33 points on the TM using noncontact LDV without any reflectors. Measurements were performed with tonal stimuli of 1, 3, and 6 kHz. Amplitudes were calculated from these measurements, and time-dependent changes in TM motion were described using a graphics application. TM motions were detected more clearly and stably at 1 and 3 kHz than at other frequencies. This is because the external auditory canal acted as a resonant tube near 3 kHz. TM motion displayed 1 peak at 1 kHz and 2 peaks at 3 kHz. Large amplitudes were detected in the posterosuperior quadrant (PSQ) at 1 kHz and in the PSQ and anteroinferior quadrant (AIQ) at 3 kHz. The entire TM showed synchronized movement centered on the PSQ at 1 kHz, with phase-shifting between PSQ and AIQ movement at 3 kHz. Amplitude was smaller at the umbo than at other parts. In contrast, amplitudes at high frequencies were too small and complicated to detect any obvious peaks. Sequential multipoint motion of the tympanic membrane showed that vibration characteristics of the TM differ according to the part and frequency.

Construction and performance of the scanning and measuring machine HOLMES used for bubble chamber holograms

International Nuclear Information System (INIS)

Drevermann, H.; Geissler, K.K.; Johansson, K.E.

1985-01-01

The construction and performance of the scanning and measuring machine HOLMES are described. It has been used to analyse in-line holograms taken with the small bubble chamber HOBC. A total of 8000 holograms has up to now been analysed on HOLMES. (orig.)

Development and trial measurement of synchrotron-radiation-light-illuminated scanning tunneling microscope

International Nuclear Information System (INIS)

Matsushima, Takeshi; Okuda, Taichi; Eguchi, Toyoaki; Ono, Masanori; Harasawa, Ayumi; Wakita, Takanori; Kataoka, Akira; Hamada, Masayuki; Kamoshida, Atsushi; Hasegawa, Yukio; Kinoshita, Toyohiko

2004-01-01

Scanning tunneling microscope (STM) study is performed under synchrotron-radiation-light illumination. The equipment is designed so as to achieve atomic resolution even under rather noisy conditions in the synchrotron radiation facility. By measuring photoexcited electron current by the STM tip together with the conventional STM tunneling current, Si 2p soft-x-ray absorption spectra are successfully obtained from a small area of Si(111) surface. The results are a first step toward realizing a new element-specific microscope

Time Resolved Scanning PIV measurements at fine scales in a turbulent jet

International Nuclear Information System (INIS)

Cheng, Y.; Torregrosa, M.M.; Villegas, A.; Diez, F.J.

2011-01-01

The temporal and spatial complexity of turbulent flows at intermediate and small scales has prevented the acquisition of full three-dimensional experimental data sets for validating classical turbulent theory and Direct Numerical Simulations (DNS). Experimental techniques like Particle Velocimetry, PIV, allow non-intrusive planar measurements of turbulent flows. The present work applied a Time Resolved Scanning PIV system, TRS-PIV, capable of obtaining three-dimensional two-component velocities to measure the small scales of a turbulent jet. When probing the small scales of these flows with PIV, the uncertainty of the measured turbulent properties are determined by the characteristics of the PIV system and specially the thickness of the laser sheet. A measurement of the particle distribution across the thickness of the laser sheet is proposed as a more detailed description of the PIV sheet thickness. The high temporal and spatial resolution of the TRS-PIV system allowed obtaining quasi-instantaneous volumetric vector fields at the far field of a round turbulent jet in water, albeit for a low Reynolds number of 1478 due to the speed limitations of the present camera and scanning system. Six of the nine components of the velocity gradient tensor were calculated from the velocity measurements. This allowed the visualization with near Kolmogorov-scale resolution of the velocity gradient structures in three-dimensional space. In general, these structures had a complex geometry corresponding to elongated shapes in the form of sheets and tubes. An analysis of the probability density function, pdf, of the velocity gradients calculated showed that the on-diagonal (off-diagonal) velocity gradient components were very similar to each other even for events at the tails of the pdfs, as required for homogeneous isotropy. The root mean square of the components of the velocity gradients is also calculated and their ratio of off-diagonal components to on-diagonal components

Pixelized measurement of {sup 99m}Tc-HDP micro particles formed in gamma correction phantom pinhole scan: A reference study

Energy Technology Data Exchange (ETDEWEB)

Jung, Joo Young; Yoon, Do Kyun; Chung, Yong An [Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Cheon, Gi Jeong; Lee, Yun Sang; Ha, Seunggyun [Radiopharmaceutical Science Laboratory, Dept. of Nuclear MedicineSeoul National University, College of Medicine, Seoul (Korea, Republic of); Bahk, Yong Whee [Dept. of Nuclear Medicine, Sung Ae General Hospital, Seoul (Korea, Republic of)

2016-09-15

Currently, traumatic bone diseases are diagnosed by assessing the micro {sup 99m}Tc-hydroxymethylene diphosphonate (HDP) uptake in injured trabeculae with ongoing osteoneogenesis demonstrated by gamma correction pinhole scan (GCPS). However, the mathematic size quantification of micro-uptake is not yet available. We designed and performed this phantom-based study to set up an in-vitro model of the mathematical calculation of micro-uptake by the pixelized measurement. The micro {sup 99m}Tc-HDP deposits used in this study were spontaneously formed both in a large standard flood and small house-made dish phantoms. The processing was as follows: first, phantoms were flooded with distilled water and {sup 99m}Tc-HDP was therein injected to induce micro {sup 99m}Tc-HDP deposition; second, the deposits were scanned using parallel-hole and pinhole collimator to generally survey {sup 99m}Tc-HDP deposition pattern; and third, the scans underwent gamma correction (GC) to discern individual deposits for size measurement. In original naïve scans, tracer distribution was simply nebulous in appearance and, hence, could not be measured. Impressively, however, GCPS could discern individual micro deposits so that they were calculated by pixelized measurement. Phantoms naturally formed micro {sup 99m}Tc-HDP deposits that are analogous to {sup 99m}Tc-HDP uptake on in-vivo bone scan. The smallest one we measured was 0.414 mm. Flooded phantoms and therein injected {sup 99m}Tc-HDP form nebulous micro {sup 99m}Tc-HDP deposits that are rendered discernible by GCPB and precisely calculable using pixelized measurement. This method can be used for precise quantitative and qualitative diagnosis of bone and joint diseases at the trabecular level.

Atomic resolution ultrafast scanning tunneling microscope with scan rate breaking the resonant frequency of a quartz tuning fork resonator.

Science.gov (United States)

Li, Quanfeng; Lu, Qingyou

2011-05-01

We present an ultra-fast scanning tunneling microscope with atomic resolution at 26 kHz scan rate which surpasses the resonant frequency of the quartz tuning fork resonator used as the fast scan actuator. The main improvements employed in achieving this new record are (1) fully low voltage design (2) independent scan control and data acquisition, where the tuning fork (carrying a tip) is blindly driven to scan by a function generator with the scan voltage and tunneling current (I(T)) being measured as image data (this is unlike the traditional point-by-point move and measure method where data acquisition and scan control are switched many times).

Irreversible denaturation of maltodextrin glucosidase studied by differential scanning calorimetry, circular dichroism, and turbidity measurements.

Science.gov (United States)

Goyal, Megha; Chaudhuri, Tapan K; Kuwajima, Kunihiro

2014-01-01

Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5-1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was kinetically controlled. The absence of a protein-concentration effect on the thermal transition indicated that the denaturation was rate-limited by a mono-molecular process. From the analysis of the calorimetric thermograms, a one-step irreversible model well represented the thermal denaturation of the protein. The calorimetrically observed thermal transitions showed excellent coincidence with the turbidity transitions monitored by UV-absorption as well as with the unfolding transitions monitored by circular dichroism. The thermal denaturation of the protein was thus rate-limited by conformational unfolding, which was followed by a rapid irreversible formation of aggregates that produced the solution turbidity. It is thus important to note that the absence of the protein-concentration effect on the irreversible thermal denaturation does not necessarily means the absence of protein aggregation itself. The turbidity measurements together with differential scanning calorimetry in the irreversible thermal denaturation of the protein provided a very effective approach for understanding the mechanisms of the irreversible denaturation. The Arrhenius-equation parameters obtained from analysis of the thermal denaturation were compared with those of other proteins that have been reported to show the one-step irreversible thermal denaturation. Maltodextrin glucosidase had sufficiently high kinetic stability with a half-life of 68 days at a physiological temperature (37°C).

Indirect measurement of the magnetocaloric effect using a novel differential scanning calorimeter with magnetic field

DEFF Research Database (Denmark)

Jeppesen, Stinus; Linderoth, Søren; Pryds, Nini

2008-01-01

A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high...

New calibration method for I-scan sensors to enable the precise measurement of pressures delivered by 'pressure garments'.

Science.gov (United States)

Macintyre, Lisa

2011-11-01

Accurate measurement of the pressure delivered by medical compression products is highly desirable both in monitoring treatment and in developing new pressure inducing garments or products. There are several complications in measuring pressure at the garment/body interface and at present no ideal pressure measurement tool exists for this purpose. This paper summarises a thorough evaluation of the accuracy and reproducibility of measurements taken following both of Tekscan Inc.'s recommended calibration procedures for I-scan sensors; and presents an improved method for calibrating and using I-scan pressure sensors. The proposed calibration method enables accurate (±2.1 mmHg) measurement of pressures delivered by pressure garments to body parts with a circumference ≥30 cm. This method is too cumbersome for routine clinical use but is very useful, accurate and reproducible for product development or clinical evaluation purposes. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

Thin-film thickness measurement using x-ray peak ratioing in the scanning electron microscope

International Nuclear Information System (INIS)

Elliott, N.E.; Anderson, W.E.; Archuleta, T.A.; Stupin, D.M.

1981-01-01

The procedure used to measure laser target film thickness using a scanning electron microscope is summarized. This method is generally applicable to any coating on any substrate as long as the electron energy is sufficient to penetrate the coating and the substrate produces an x-ray signal which can pass back through the coating and be detected

Decommissioning and dismantling: Qualification of gamma scanning method for decontrolling measurement of radioactive wastes. Final report

International Nuclear Information System (INIS)

Genrich, V.; Sattler, P.

1998-01-01

At the time being measurements for the release of buildings and parts of buildings are mainly performed with contamination monitors, free release equipment, wipe test a. s. o. The technical application of in-situ gamma-scanning systems for release measurement should be demonstrated with this research project. This method presents considerable advantages in comparison with standard procedures, as f. ex. reduction of radioactive waste or area covering investigation of the inspected building. A system with a NaI(Tl) and a HPGe-detector was applied. With the high-resolving system it can be shown that also low limit values can be kept with short measurement time. With the NaI(Tl)-detector system it was demonstrated that with limit values lower than 1 Bq/m 3 there may be problems observing the limit values. The investigation showed that especially the high-resolving system for the release measurement of buildings (f. ex. floors, walls, complete rooms) is well-suited. The in-situ gamma-scanning shows big advantages in its economy as f. ex. no sampling and only short measurement times are required. The sharp limitation of the existing contamination and the reduction of radioactive waste involved herewith are further advantages which justify the application of this measurement technique. (orig.)

Canopy wake measurements using multiple scanning wind LiDARs

Science.gov (United States)

Markfort, C. D.; Carbajo Fuertes, F.; Iungo, V.; Stefan, H. G.; Porte-Agel, F.

2014-12-01

Canopy wakes have been shown, in controlled wind tunnel experiments, to significantly affect the fluxes of momentum, heat and other scalars at the land and water surface over distances of ˜O(1 km), see Markfort et al. (EFM, 2013). However, there are currently no measurements of the velocity field downwind of a full-scale forest canopy. Point-based anemometer measurements of wake turbulence provide limited insight into the extent and details of the wake structure, whereas scanning Doppler wind LiDARs can provide information on how the wake evolves in space and varies over time. For the first time, we present measurements of the velocity field in the wake of a tall patch of forest canopy. The patch consists of two uniform rows of 40-meter tall deciduous, plane trees, which border either side of the Allée de Dorigny, near the EPFL campus. The canopy is approximately 250 m long, and it is approximately 40 m wide, along the direction of the wind. A challenge faced while making field measurements is that the wind rarely intersects a canopy normal to the edge. The resulting wake flow may be deflected relative to the mean inflow. Using multiple LiDARs, we measure the evolution of the wake due to an oblique wind blowing over the canopy. One LiDAR is positioned directly downwind of the canopy to measure the flow along the mean wind direction and the other is positioned near the canopy to evaluate the transversal component of the wind and how it varies with downwind distance from the canopy. Preliminary results show that the open trunk space near the base of the canopy results in a surface jet that can be detected just downwind of the canopy and farther downwind dissipates as it mixes with the wake flow above. A time-varying recirculation zone can be detected by the periodic reversal of the velocity near the surface, downwind of the canopy. The implications of canopy wakes for measurement and modeling of surface fluxes will be discussed.

Spatial filtering self-velocimeter for vehicle application using a CMOS linear image sensor

Science.gov (United States)

He, Xin; Zhou, Jian; Nie, Xiaoming; Long, Xingwu

2015-03-01

The idea of using a spatial filtering velocimeter (SFV) to measure the velocity of a vehicle for an inertial navigation system is put forward. The presented SFV is based on a CMOS linear image sensor with a high-speed data rate, large pixel size, and built-in timing generator. These advantages make the image sensor suitable to measure vehicle velocity. The power spectrum of the output signal is obtained by fast Fourier transform and is corrected by a frequency spectrum correction algorithm. This velocimeter was used to measure the velocity of a conveyor belt driven by a rotary table and the measurement uncertainty is ˜0.54%. Furthermore, it was also installed on a vehicle together with a laser Doppler velocimeter (LDV) to measure self-velocity. The measurement result of the designed SFV is compared with that of the LDV. It is shown that the measurement result of the SFV is coincident with that of the LDV. Therefore, the designed SFV is suitable for a vehicle self-contained inertial navigation system.

Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.

Science.gov (United States)

Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

2015-12-23

In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.

Contact Versus Non-Contact Measurement of a Helicopter Main Rotor Composite Blade

Science.gov (United States)

Luczak, Marcin; Dziedziech, Kajetan; Vivolo, Marianna; Desmet, Wim; Peeters, Bart; Van der Auweraer, Herman

2010-05-01

The dynamic characterization of lightweight structures is particularly complex as the impact of the weight of sensors and instrumentation (cables, mounting of exciters…) can distort the results. Varying mass loading or constraint effects between partial measurements may determine several errors on the final conclusions. Frequency shifts can lead to erroneous interpretations of the dynamics parameters. Typically these errors remain limited to a few percent. Inconsistent data sets however can result in major processing errors, with all related consequences towards applications based on the consistency assumption, such as global modal parameter identification, model-based damage detection and FRF-based matrix inversion in substructuring, load identification and transfer path analysis [1]. This paper addresses the subject of accuracy in the context of the measurement of the dynamic properties of a particular lightweight structure. It presents a comprehensive comparative study between the use of accelerometer, laser vibrometer (scanning LDV) and PU-probe (acoustic particle velocity and pressure) measurements to measure the structural responses, with as final aim the comparison of modal model quality assessment. The object of the investigation is a composite material blade from the main rotor of a helicopter. The presented results are part of an extensive test campaign performed with application of SIMO, MIMO, random and harmonic excitation, and the use of the mentioned contact and non-contact measurement techniques. The advantages and disadvantages of the applied instrumentation are discussed. Presented are real-life measurement problems related to the different set up conditions. Finally an analysis of estimated models is made in view of assessing the applicability of the various measurement approaches for successful fault detection based on modal parameters observation as well as in uncertain non-deterministic numerical model updating.

Contact Versus Non-Contact Measurement of a Helicopter Main Rotor Composite Blade

International Nuclear Information System (INIS)

Luczak, Marcin; Dziedziech, Kajetan; Peeters, Bart; Van der Auweraer, Herman; Vivolo, Marianna; Desmet, Wim

2010-01-01

The dynamic characterization of lightweight structures is particularly complex as the impact of the weight of sensors and instrumentation (cables, mounting of exciters...) can distort the results. Varying mass loading or constraint effects between partial measurements may determine several errors on the final conclusions. Frequency shifts can lead to erroneous interpretations of the dynamics parameters. Typically these errors remain limited to a few percent. Inconsistent data sets however can result in major processing errors, with all related consequences towards applications based on the consistency assumption, such as global modal parameter identification, model-based damage detection and FRF-based matrix inversion in substructuring, load identification and transfer path analysis [1]. This paper addresses the subject of accuracy in the context of the measurement of the dynamic properties of a particular lightweight structure. It presents a comprehensive comparative study between the use of accelerometer, laser vibrometer (scanning LDV) and PU-probe (acoustic particle velocity and pressure) measurements to measure the structural responses, with as final aim the comparison of modal model quality assessment. The object of the investigation is a composite material blade from the main rotor of a helicopter. The presented results are part of an extensive test campaign performed with application of SIMO, MIMO, random and harmonic excitation, and the use of the mentioned contact and non-contact measurement techniques. The advantages and disadvantages of the applied instrumentation are discussed. Presented are real-life measurement problems related to the different set up conditions. Finally an analysis of estimated models is made in view of assessing the applicability of the various measurement approaches for successful fault detection based on modal parameters observation as well as in uncertain non-deterministic numerical model updating.

Measuring voltage transients with an ultrafast scanning tunneling microscope

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

1997-01-01

circuit, where the tunneling tip is directly connected to the current amplifier of the scanning tunneling microscope, this dependence is eliminated. Ail results can be explained with coupling through the geometrical capacitance of the tip-electrode junction. By illuminating the current......We use an ultrafast scanning tunneling microscope to resolve propagating voltage transients in space and time. We demonstrate that the previously observed dependence of the transient signal amplitude on the tunneling resistance was only caused by the electrical sampling circuit. With a modified...

Measurement of the lateral recess angle as a possible alternative for evaluation of the lateral recess stenosis on a CT scan

International Nuclear Information System (INIS)

Strojnik, T.

2001-01-01

Stenosis of the lateral recess in the lumbar spinal canal is a clinical problem, especially in terms of surgical management. Criteria for the diagnosis and surgical treatment of lateral recess stenosis (LRS) are not clearly defined. Several authors have suggested measurement of the lateral recess height (LRH) on computed tomography (CT) scans as a helpful tool for making decisions in regard of management. The present study is based an the assumption that measurement of the lateral recess angle (LRA) may be useful in the clinical management of lateral recess stenosis. The reliability and significance of the results have been analyzed. In 35 patients, the stenosis was confirmed by intraoperative measurement of the lateral recess height. Fifty-three affected lateral recesses were analyzed. Before surgery, the heights on CT scans were measured. The mean value was 3.3 mm (SD = 0.9 mm), while 41 of them were 3.6 mm or less. Furthermore, the angles on CT scans were evaluated. The mean value was 25.9 degrees (SD = 4.9 degrees), 48 of them were 30 degrees or less and only 5 of them achieved more than 30 degrees. Results reveal that the best quantitative determination of a lateral recess stenosis is a CT scan angle measurement with a critical value of 30 degrees. A CT scan height of 3.6 mm or less is also indicative of stenosis. Statistical evaluation of the data by multiple regression analysis revealed agreement between intraoperative findings and measured heights (p = 0.02), while even better results were noted for angles (p < 0.01). Interfacet distance (IF) was found to be least predictive (p = 0.04). (author)

Verification of a BWR code package by gamma scan measurements

International Nuclear Information System (INIS)

Nakajima, Tsuyoshi; Iwamoto, Tatsuya; Kumanomido, Hironori

1996-01-01

High-burnup 8 x 8 fuel with a large central water rod (called step 2 fuel) has been recently introduced to the latest Japanese boiling water reactor (BWR) plants. Lanthanum-140 gamma intensity is almost directly related to nodal powers. By gamma scan measurement, the axial distribution of 140 La in the exposed fuel was measured at the end of cycle (EOC) 1 and was compared with the calculation by a BWR code package TGBLA/LOGOS. The multienrichment fuel-type core (MEC) design was adopted for the initial cycle core of the plants. The MEC design contains three different enrichment types of fuels to simulate the equilibrium cycles, achieve much higher discharge exposure, and save fuel cycle cost, and the low-enrichment fuels are loaded in periphery and in control cells. Such MEC design could be a challenge to the BWR design methods because of the large spectrum mismatch among the fuel assemblies of the different enrichments. The aforementioned comparison has shown that the accuracy of the TGBLA/LOGOS code package is satisfactory

Non-invasive assessment of peripheral arterial disease: Automated ankle brachial index measurement and pulse volume analysis compared to duplex scan.

Science.gov (United States)

Lewis, Jane Ea; Williams, Paul; Davies, Jane H

2016-01-01

This cross-sectional study aimed to individually and cumulatively compare sensitivity and specificity of the (1) ankle brachial index and (2) pulse volume waveform analysis recorded by the same automated device, with the presence or absence of peripheral arterial disease being verified by ultrasound duplex scan. Patients (n=205) referred for lower limb arterial assessment underwent ankle brachial index measurement and pulse volume waveform recording using volume plethysmography, followed by ultrasound duplex scan. The presence of peripheral arterial disease was recorded if ankle brachial index 50% was evident with ultrasound duplex scan. Outcome measure was agreement between the measured ankle brachial index and interpretation of pulse volume waveform for peripheral arterial disease diagnosis, using ultrasound duplex scan as the reference standard. Sensitivity of ankle brachial index was 79%, specificity 91% and overall accuracy 88%. Pulse volume waveform sensitivity was 97%, specificity 81% and overall accuracy 85%. The combined sensitivity of ankle brachial index and pulse volume waveform was 100%, specificity 76% and overall accuracy 85%. Combining these two diagnostic modalities within one device provided a highly accurate method of ruling out peripheral arterial disease, which could be utilised in primary care to safely reduce unnecessary secondary care referrals.

Automated quantification of pulmonary emphysema from computed tomography scans: comparison of variation and correlation of common measures in a large cohort

Science.gov (United States)

Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.

2010-03-01

The purpose of this work was to retrospectively investigate the variation of standard indices of pulmonary emphysema from helical computed tomographic (CT) scans as related to inspiration differences over a 1 year interval and determine the strength of the relationship between these measures in a large cohort. 626 patients that had 2 scans taken at an interval of 9 months to 15 months (μ: 381 days, σ: 31 days) were selected for this work. All scans were acquired at a 1.25mm slice thickness using a low dose protocol. For each scan, the emphysema index (EI), fractal dimension (FD), mean lung density (MLD), and 15th percentile of the histogram (HIST) were computed. The absolute and relative changes for each measure were computed and the empirical 95% confidence interval was reported both in non-normalized and normalized scales. Spearman correlation coefficients are computed between the relative change in each measure and relative change in inspiration between each scan-pair, as well as between each pair-wise combination of the four measures. EI varied on a range of -10.5 to 10.5 on a non-normalized scale and -15 to 15 on a normalized scale, with FD and MLD showing slightly larger but comparable spreads, and HIST having a much larger variation. MLD was found to show the strongest correlation to inspiration change (r=0.85, pemphysema index and fractal dimension have the least variability overall of the commonly used measures of emphysema and that they offer the most unique quantification of emphysema relative to each other.

Inter-Scan Reproducibility of Carotid Plaque Volume Measurements by 3-D Ultrasound

DEFF Research Database (Denmark)

Sandholt, Benjamin V; Collet-Billon, Antoine; Entrekin, Robert

2018-01-01

(PPV) measure centered on MPT. Total plaque volume (TPV), PPV from a 10-mm segment and MPT were measured using dedicated semi-automated software on 38 plaques from 26 patients. Inter-scan reproducibility was assessed using the t-test, Bland-Altman plots and Pearson's correlation coefficient....... There was a mean difference of 0.01 mm in MPT (limits of agreement: -0.45 to 0.42 mm, Pearson's correlation coefficient: 0.96). Both volume measurements exhibited high reproducibility, with PPV being superior (limits of agreement: -35.3 mm3to 33.5 mm3, Pearson's correlation coefficient: 0.96) to TPV (limits...... of agreement: -88.2 to 61.5 mm3, Pearson's correlation coefficient: 0.91). The good reproducibility revealed by the present results encourages future studies on establishing plaque quantification as part of cardiovascular risk assessment and for follow-up of disease progression over time....

Comparison of anterior segment measurements using Sirius Topographer® and Nidek Axial Length-Scan® with assessing repeatability in patients with cataracts

Directory of Open Access Journals (Sweden)

Resat Duman

2018-01-01

Full Text Available Purpose: The purpose of this study is to evaluate anterior segment measurements obtained using CSO Sirius Topographer® (CSO, Firenze, Italy and Nidek Axial Length (AL-Scan® (Nidek CO., Gamagori, Japan. Methods: A total of 43 eyes of 43 patients were included in this prospective study. The central corneal thickness (CCT, anterior chamber depth (ACD, white-to-white distance (WTW, flat keratometry (K1, steep keratometry (K2, and mean keratometry (K values were randomly measured three times with each device by the same examiner. The intraclass correlation coefficient of repeatability was analyzed. The compatibility of both devices was evaluated using the 95% limits of the agreement proposed by Bland and Altman. Results: Examiner achieved high repeatability for all parameters on each device except the WTW measured by Sirius. All measurements except WTW and K1 taken with the Sirius were higher than that taken with the Nidek AL-Scan®. The difference in CCT, ACD, and WTW values was statistically significant. Conclusion: High repeatability of the measurements was achieved on both devices. Although Km, K1, and K2 measurements of the Sirius and the AL-Scan® showed good agreement, WTW, CCT, and ACD measurements significantly differed between two devices. Thus, anterior segment measurements except for Km, K1, and K2 cannot be used interchangeably between Sirius and Nidek AL-Scan® devices.

Research on Mechanical Properties of Concrete Constructs Based on Terrestrial Laser Scanning Measurement

Directory of Open Access Journals (Sweden)

Hao Yang

2016-05-01

Full Text Available Terrestrial laser scanning (TLS technology is broadly accepted as a structural health monitoring device for reinforced concrete (RC composite structures. Both experiments and numerical analysis are considered. In this submit, measurements were conducted for the composite concrete beams. The emphasis in numerical simulation is given on finite element methods (FEM which is corrected by the response surface methodology (RSM. Aspects considered are effects of material parameters and variation in geometry. This paper describes our recent progress on FEM modeling of damages in concrete composite structures based on the TLS measurement. We also focus on the research about mechanical properties of concrete constructs here.

Measurement of effective left ventricular ejection fraction by radiocardiography associated with cardiac chamber scanning

Energy Technology Data Exchange (ETDEWEB)

de Vernejoul, P; Fauchet, M; Rimbert, J -N; Gambini, D; Agnely, J [Hopital Necker-Enfants-Malades, 75 - Paris (France)

1976-03-01

Left ventricular ejection fraction is usually measured by cineangiocardiography. When radiocardiography and cardiac chamber scanning are associated, it allows an effective left ventricular ejection fraction assessment. Ejection fractions calculated by both methods are the same in normal subjects. They are different in the case of left valvular heart disease with insufficiency. The whole regurgitation fraction can be calculated from this difference.

Measurement of effective left ventricular ejection fraction by radiocardiography associated with cardiac chamber scanning

International Nuclear Information System (INIS)

Vernejoul, Pierre de; Fauchet, Michel; Rimbert, J.-N.; Gambini, Denis; Agnely, Jacqueline

1976-01-01

Left ventricular ejection fraction is usually measured by cineangiocardiography. When radiocardiography and cardiac chamber scanning are associated, it allows an effective left ventricular ejection fraction assessment. Ejection fractions calculated by both methods are the same in normal subjects. They are different in the case of left valvular heart disease with insufficiency. The whole regurgitation fraction can be calculated from this difference [fr

Scanning conoscopy measurement of the optical properties of chiral smectic liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Bitri, N. [Laboratoire de Physique de la Matiere Molle Faculte des Sciences de Tunis, 2092 El Manar TUNIS (Tunisia); Centre de Recherches Paul Pascal, 115, Av. Albert-Schweitzer, 33600 Pessac (France)], E-mail: bitri@crpp-bordeaux.cnrs.fr; Gharbi, A. [Laboratoire de Physique de la Matiere Molle Faculte des Sciences de Tunis, 2092 El Manar TUNIS (Tunisia); Marcerou, J.P. [Centre de Recherches Paul Pascal, 115, Av. Albert-Schweitzer, 33600 Pessac (France)

2008-11-30

We report on a new scanning conoscopic method which, by rotating the sample and analyzing the ellipticity of transmitted light, provides an accurate tool to measure the temperature dependence of the two indices n{sub e}, n{sub o} and of the optical activity for uniaxial liquid crystals. Their determination is useful to give informations about the tilt angle {theta} and the macroscopic helicity in the different phases and then on the structures of the liquid crystal phases. We tested the method with the reference compound (99% S, 1% R)MHPOBC.

Digital PIV Measurements in the Diffuser of a High Speed Centrifugal Compressor

Science.gov (United States)

Wernet, Mark P.

1998-01-01

Particle Imaging Velocimetry (PIV) is a powerful measurement technique which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. PIV data are measured simultaneously at multiple points in space, which enables the investigation of the non-stationary spatial structures typically encountered in turbomachinery. Obtaining ample optical access, sufficiently high seed particle concentrations and accurate synchronization of image acquisition relative to impeller position are the most formidable tasks in the successful implementation of PIV in turbomachinery. Preliminary results from the successful application of the standard 2-D digital PIV technique in the diffuser of a high speed centrifugal compressor are presented. Instantaneous flow. measurements were also obtained during compressor surge.

Laser Doppler measurement and CFD validation in 3 × 3 bundle flow

Energy Technology Data Exchange (ETDEWEB)

Xiong, Jinbiao, E-mail: xiongjinbiao@sjtu.edu.cn [School of Nuclear Science and Engineering, Shanghai Jiao Tong University (China); Yu, Yang [School of Nuclear Science and Engineering, Shanghai Jiao Tong University (China); Yu, Nan; Fu, Xiaoliang [State Nuclear Power Software Development Center, National Energy Key Laboratory of Nuclear Power Software (China); Wang, Hongyan [School of Nuclear Science and Engineering, Shanghai Jiao Tong University (China); Cheng, Xu [Karlsruhe Institute of Technology (Germany); Yang, Yanhua [School of Nuclear Science and Engineering, Shanghai Jiao Tong University (China); State Nuclear Power Software Development Center, National Energy Key Laboratory of Nuclear Power Software (China)

2014-04-01

Highlights: • Five-beam LDV is operated in the three-beam mode to measure 3 × 3 bundle flow. • Correlation and FFT techniques are applied to analyze the flow structure. • Large coherent structure is observed in gaps between different subchannels. • The Reynolds stress models predict weak mixing between different subchannels. - Abstract: The five-beam three-component laser Doppler system is operated in the three-beam two-component mode to measure the 3 × 3 bundle flow with simple grid spacer. Experiment has been conducted at Re = 15,200 and 29,900. According to the experiment result, the root mean square (RMS) of axial velocity fluctuation shows large value in the gap and the near-wall region of the edge sub-channel which is induced by the axial velocity gradient. Significant intensity of lateral velocity fluctuation is observed which indicates the strong lateral mixing in a 3 × 3 rod bundle. Through the correlation analysis coherent structures have been observed in the gap region. The spectral analysis shows that the LDV measurement complies to the Komogorov spectrum law, f{sup −5/3}, well. The low-frequency peak spectral density of the axial velocity fluctuation has been observed in the gap region connecting sub-channels with velocity difference. The performance of the SSG model and the baseline Reynolds stress model are investigated based on the experiment result. The models predict higher axial velocity in the interior sub-channel and lower in the edge and corner ones than the experiment result. Large discrepancy between the calculated and measured axial flow velocity is resulted from failure in calculating the strong negative u{sup ′}w{sup ′¯} in the gap region connecting different sub-channels.

MEASURING LEAF WATER CONTENT USING MULTISPECTRAL TERRESTRIAL LASER SCANNING

Directory of Open Access Journals (Sweden)

S. Junttila

2017-10-01

Full Text Available Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS. LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2 in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

Measuring Leaf Water Content Using Multispectral Terrestrial Laser Scanning

Science.gov (United States)

Junttila, S.; Vastaranta, M.; Linnakoski, R.; Sugano, J.; Kaartinen, H.; Kukko, A.; Holopainen, M.; Hyyppä, H.; Hyyppä, J.

2017-10-01

Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC) is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS). LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2) in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

Measurement of lung volume by lung perfusion scanning using SPECT and prediction of postoperative respiratory function

International Nuclear Information System (INIS)

Andou, Akio; Shimizu, Nobuyosi; Maruyama, Shuichiro

1992-01-01

Measurement of lung volume by lung perfusion scanning using single photon emission computed tomography (SPECT) and its usefulness for the prediction of respiratory function after lung resection were investigated. The lung volumes calculated in 5 patients by SPECT (threshold level 20%) using 99m Tc-macroaggregated albumin (MAA), related very closely to the actually measured lung volumes. This results prompted us to calculate the total lung volume and the volume of the lobe to be resected in 18 patients with lung cancer by SPECT. Based on the data obtained, postoperative respiratory function was predicted. The predicted values of forced vital capacity (FVC), forced expiratory volume (FEV 1.0 ), and maximum vital volume (MVV) showed closer correlations with the actually measured postoperative values (FVC, FEV 1.0 , MVV : r=0.944, r=0.917, r=0.795 respectively), than the values predicted by the ordinary lung perfusion scanning. This method facilitates more detailed evaluation of local lung function on a lobe-by-lobe basis, and can be applied clinically to predict postoperative respiratory function. (author)

The usefulness of measurement of whole body count in assessing bone marrow metastasis in cancer patients with increased periarticular bone uptake on follow-up bone scan: a comparison with bone marrow scan

International Nuclear Information System (INIS)

Jin, Seong Chan; Choi, Yun Young; Cho, Suk Shin

2003-01-01

Increased periarticular uptake could be associated with peripheral bone marrow expansion in cancer patients with axial bone marrow metastasis. We compared bone scan and bone marrow scan to investigate whether the increased whole body count in patients with increased periarticular uptake on bone scan is useful in the diagnosis of axial marrow metastasis, and evaluate the role of additional bone marrow scan in these cases. Twelve patients with malignant diseases who showed increased periarticular uptake on bone scan were included. Whole body count was measured on bone scan and it is considered to be increased when the count is more than twice of other patients. Bone marrow scan was taken within 3-7 days. Five hematologic malignancy, 3 stomach cancer, 2 breast cancer, 1 prostate cancer and 1 lung canner were included. All three patients with increased whole body count on bone scan showed axial marrow suppression and peripheral marrow expansion. Eight of 9 patients without increased whole body count showed axial marrow suppression and peripheral marrow expansion. One turned out to be blastic crisis of chronic myelogeneous leukemia, and seven showed normal axial marrow with peripheral marrow expansion in chronic anemia of malignancy. The last one without increased whole body count showed normal bone marrow scan finding. Increased whole body count on bone scan could be a clue to axial bone marrow metastasis in cancer patients with increased periarticular uptake, and bone marrow scan is a valuable method for differential diagnosis in these cases

Multichannel heterodyne radiometers with fast-scanning backward-wave oscillators for ECE measurement on HT-7 tokamak

International Nuclear Information System (INIS)

Zhang, S.Y.; Poznyak, V.I.; Ploskirev, G.; Kalupin, D.; Wan, Y.X.; Xie, J.K.; Luo, J.R.; Li, J.G.; Gao, X.; Wan, B.N.; Zhang, X.D.; Wang, K.J.; Kuang, G.L.

2001-01-01

Two sets of fast-scanning heterodyne radiometer receiver systems employing backward-wave oscillators (BWOs) in 78-118 and 118-178 GHz were developed and installed for electron cyclotron emission (ECE) measurements on HT-7 superconducting tokamak. The double sideband (DSB) radiometer in 78-118 GHz measures 16 ECE frequency points with a scanning time period of 0.65 ms. The other radiometer in 118-178 GHz consists of one independent channel of DSB heterodyne receiver with intermediate frequency (IF) of 100-500 MHz and two channels of single sideband (SSB) heterodyne receiver that are sensitive to upper sideband and lower sideband individually; the IF frequency of the SSB channels are 1.5 GHz around the local oscillator frequencies with 1 GHz bandwidth. By employing a novel design, this unique radiometer measures 3 ECE frequency points at each of the 16 local oscillator frequency points in 118-178 GHz, and the full band can be swept in 0.65 ms period, thus the radiometer measures 48 ECE frequency points in 0.65 ms in principle. Each of the local oscillators' frequency points can be preset by program to meet specific physics interests. Horizontal view of ECE was installed to measure electron temperature profiles; vertically viewing optics along a perpendicular chord was also installed to study nonthermal ECE spectra. Preliminary measurement results were presented during ohmic and pellet injection plasmas

Transient measurements with an ultrafast scanning tunneling microscope

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

1998-01-01

We use a photoconductively gated ultrafast scanning tunneling microscope to resolve laser-induced transients on transmission lines and photoconductors. The photoconductive switch on the tunneling probe is illuminated through a rigidly attached fiber. The use of the fiber enables us to scan across...... the transmission line while the change in delay time between pump beam (on the sample) and probe beam (on the probe) provides the temporal information. The investigated photoconductor sample is a low-temperature-grown GaAs layer placed on a sapphire substrate with a thin, semitransparent gold layer. In tunneling...... mode the probe is sensitive to laser-induced field changes in the semiconductor layer. Laser-induced transient signals of 2.2 ps widths are detected. As for the transmission lines, the signals can be explained by a capacitive coupling across the tunneling gap....

RF Phase Scan for Beam Energy Measurement of KOMAC DTL

Energy Technology Data Exchange (ETDEWEB)

Kim, Hansung; Kwon, Hyeokjung; Kim, Seonggu; Lee, Seokgeun; Cho, Yongsub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The energy gain through the drift tube linac is a function of the synchronous phase, therefore, the output beam energy from DTL can be affected by the RF phase setting in low-level RF (LLRF) system. The DTL at Korea Multi-purpose Accelerator Complex (KOMAC) consists of 11 tanks and the RF phase setting in each tank should be matched for synchronous acceleration in successive tanks. That means a proper setting of RF phase in each DTL tank is critical for efficient and loss-free operation. The matching RF phase can be determined based on the output energy measurement from the DTL tank. The beam energy can be measured by several methods. For example, we can use a bending magnet to determine the beam energy because the higher momentum of beam means the less deflection angle in the fixed magnetic field. By measuring the range of proton beam through a material with known stopping power also can be utilized to determine the beam energy. We used a well-known time-of-flight method to determine the output beam energy from the DTL tank by measuring beam phase with a beam position monitor (BPM). Based on the energy measurement results, proper RF operating point could be obtained. We performed a RF phase scan to determine the output beam energy from KOMAC DTL by using a time-of-flight method and to set RF operating point precisely. The measured beam energy was compared with a beam dynamics simulation and showed a good agreement. RF phase setting is critical issue for the efficient operation of the proton accelerator, we have a plan to implement and integrate the RF phase measurement system into an accelerator control system for future need.

Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates.

Science.gov (United States)

Zhang, Hao; Li, Xianqi; Chen, Yunmei; Park, Jewook; Li, An-Ping; Zhang, X-G

2017-01-01

We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a "rubber band" model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.

Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates

Directory of Open Access Journals (Sweden)

Hao Zhang

2017-01-01

Full Text Available We present an image postprocessing framework for Scanning Tunneling Microscope (STM to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a “rubber band” model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA. The numerical results on measurement from copper(111 surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.

Emittance scans for CMS luminosity calibration in 2017

CERN Document Server

CMS Collaboration

2018-01-01

Emittance scans are short van der Meer type scans performed at the beginning and at the end of LHC fills. The beams are scanned against each other in X and Y planes in 7 displacement steps. These scans are used for LHC diagnostics and since 2017 for a cross check of the CMS luminosity calibration. An XY pair of scans takes around 3 minutes. The BRIL project provides to LHC three independent online luminosity measurement from the Pixel Luminosity Telescope (PLT), the Fast Beam Condition Monitor (BCM1F) and the Forward calorimeter (HF). The excellent performance of the BRIL detector front-ends, fast back-end electronics and CMS XDAQ based data processing and publication allow the use of emittance scans for linearity and stability studies of the luminometers. Emittance scans became a powerful tool and dramatically improved the understanding of the luminosity measurement during the year. Since each luminometer is independently calibrated in every scan the measurements are independent and ratios of luminometers ca...

Simultaneous measurement and quantitation of 4-hydroxyphenylacetic acid and dopamine with fast-scan cyclic voltammetry.

Science.gov (United States)

Shin, Mimi; Kaplan, Sam V; Raider, Kayla D; Johnson, Michael A

2015-05-07

Caged compounds have been used extensively to investigate neuronal function in a variety of preparations, including cell culture, ex vivo tissue samples, and in vivo. As a first step toward electrochemically measuring the extent of caged compound photoactivation while also measuring the release of the catecholamine neurotransmitter, dopamine, fast-scan cyclic voltammetry at carbon-fiber microelectrodes (FSCV) was used to electrochemically characterize 4-hydroxyphenylacetic acid (4HPAA) in the absence and presence of dopamine. 4HPAA is a by-product formed during the process of photoactivation of p-hydroxyphenacyl-based caged compounds, such as p-hydroxyphenylglutamate (pHP-Glu). Our data suggest that the oxidation of 4HPAA occurs through the formation of a conjugated species. Moreover, we found that a triangular waveform of -0.4 V to +1.3 V to -0.4 V at 600 V s(-1), repeated every 100 ms, provided an oxidation current of 4HPAA that was enhanced with a limit of detection of 100 nM, while also allowing the detection and quantitation of dopamine within the same scan. Along with quantifying 4HPAA in biological preparations, the results from this work will allow the electrochemical measurement of photoactivation reactions that generate 4HPAA as a by-product as well as provide a framework for measuring the photorelease of electroactive by-products from caged compounds that incorporate other chromophores.

Status of automated nuclear scanning systems

International Nuclear Information System (INIS)

Gold, R.; Roberts, J.H.; Preston, C.C.; McNeece, J.P.; Ruddy, F.H.

1983-07-01

Present day minicomputers and microprocessors enable a range of automation, from partial to total, of tasks once thought beyond approach. The status of three computer controlled systems for quantitative track measurements is reviewed. Two systems, the Hanford optical track scanner (HOTS) and an automated scanning electron microscope (ASEM) are used for scanning solid state track recorders (SSTR). The third systems, the emulsion scanning processor (ESP), is an interactive system used to measure the length of proton tracks in nuclear research emulsions (NRE). Current limitations of these systems for quantitative track scanning are presented. Experimental uncertainties attained with these computer controlled systems are described using results obtained from reactor neutron dosimetry

CT-scan-monitored electrical-resistivity measurements show problems achieving homogeneous saturation

International Nuclear Information System (INIS)

Sprunt, E.S.; Davis, R.M.; Muegge, E.L.; Desai, K.P.

1991-01-01

This paper reports on x-ray computerized tomography (CT) scans obtained during measurement of the electrical resistivity of core samples which revealed some problems in obtaining uniform saturation along the lengths of the samples. The electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent used in electric-log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone: a stationary front formed in one sample at 1-psi oil/brine capillary pressure, a moving front formed at oil/brine capillary pressure ≤4 psi in samples tested in fresh mixed-wettability and cleaned water-wet states, and the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated in the samples

Measurement of the enthalpies of vaporization and sublimation of solids aromatic hydrocarbons by differential scanning calorimetry

International Nuclear Information System (INIS)

Rojas, Aaron; Orozco, Eulogio

2003-01-01

An experimental procedure is proposed for direct measurement of the heat involved in the vaporization of a solid organic compound above its normal melting temperature. This technique consists on the fusion of a solid aromatic hydrocarbon, which is then vaporized by a sudden decrease of the pressure. The direct register of heat flow as function of time by differential scanning calorimetry allows the quantifying of the enthalpy of vaporization of compounds such as phenanthrene, β-naphthol, pyrene, and anthracene. Enthalpies of vaporization were measured in an isothermal mode over a range of temperatures from 10 to 20 K above the melting temperatures of each compound, while enthalpies of fusion were determined from separate experiments performed in a scanning mode. Enthalpies of sublimation are computed from results of fusion and vaporization, and then compared with results from the literature, which currently are obtained by calorimetric or indirect techniques

Bayesian reconstruction of seafloor shape from side-scan sonar measurements using a Markov Random Field

OpenAIRE

Woock, P.; Pak, Alexey

2014-01-01

To explore the seafloor, a side-scan sonar emits a directed acoustic signal and then records the returning (reflected) signal intensity as a function of time. The inversion of that process is not unique: multiple shapes may lead to identical measured responses. In this work, we suggest a Bayesian approach to reconstructing the 3D shape of the seafloor from multiple sonar measurements, inspired by the state-of-the-art methods of inverse raytracing that originated in computer vision. The space ...

Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings

Directory of Open Access Journals (Sweden)

Samuel Lawman

2017-04-01

Full Text Available The measurement of the thicknesses of layers is important for the quality assurance of industrial coating systems. Current measurement techniques only provide a limited amount of information. Here, we show that spectral domain Line Field (LF Optical Coherence Tomography (OCT is able to return to the user a cross sectional B-Scan image in a single shot with no mechanical moving parts. To reliably extract layer thicknesses from such images of automotive paint systems, we present an automatic graph search image segmentation algorithm. To show that the algorithm works independently of the OCT device, the measurements are repeated with a separate time domain Full Field (FF OCT system. This gives matching mean thickness values within the standard deviations of the measured thicknesses across each B-Scan image. The combination of an LF-OCT with graph search segmentation is potentially a powerful technique for the quality assurance of non-opaque industrial coating layers.

A measurement-based generalized source model for Monte Carlo dose simulations of CT scans.

Science.gov (United States)

Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

2017-03-07

The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients' CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

Science.gov (United States)

Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

2017-03-01

The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

Simultaneous measurement of refractive index and thickness distributions using low-coherence digital holography and vertical scanning

International Nuclear Information System (INIS)

Watanabe, Kaho; Ohshima, Masashi; Nomura, Takanori

2014-01-01

The simultaneous measurement method of a refractive index distribution and a thickness distribution using low-coherence digital holography with a vertical scanning is proposed. The proposed method consists of a combination of digital holography and low-coherence interferometry. The introduction of a datum plane enables the measurement of both a refractive index distribution and a thickness distribution. By the optical experiment, the potential of the proposed method is confirmed. (paper)

Improved path imbalance measurement of a fiber-optic interferometer based on frequency scanning interferometry

International Nuclear Information System (INIS)

Hou, C B; Wang, J G; Yang, J; Li, H Y; Peng, F; Yuan, L B; Yuan, Y G

2017-01-01

We developed a path imbalance measuring system using a reference interferometer with alterable optical path difference (OPD), aiming to eliminate the uncertainties due to synthetic wavelength measurement and remove the requirement of a known and stable reference OPD in frequency scanning interferometry. The path imbalance can be solved by using the phase ratios between the two interferometers produced before and after altering the OPD in the reference interferometer. The results have shown that the measurement uncertainty and the path imbalance are linearly related and a combined relative uncertainty of 4.9  ×  10 −6 (1 σ ) in path imbalance measurement over a range from 0.5 m to 50 m is achieved. Besides, we analyzed the contributions to the uncertainty that limit the performance of the system, and we discussed how to obtain a better measurement uncertainty. (paper)

Scanning by use of TV

International Nuclear Information System (INIS)

Drevermann, H.

1981-01-01

The use of TV read out for scanning and measuring holographic pictures seems to give less problems than the use of optical projection as is usual for conventional bubble chamber photos. Whereas the measuring of conventional bubble chamber pictures seems to give no problems, it is not clear whether scanning by use of TV is possible. Therefore scanning pictures from experiment NA16 (taken in LEBC) with TV only was tried using the TV system of ERASME, where the CRT system is used as a camera. It should be mentioned that this system, being a flying spot device, cannot be adapted for holography. (author)

An ultrahigh-vacuum cryostat for simultaneous scanning tunneling microscopy and magneto-transport measurements down to 400 mK.

Science.gov (United States)

Liebmann, Marcus; Bindel, Jan Raphael; Pezzotta, Mike; Becker, Stefan; Muckel, Florian; Johnsen, Tjorven; Saunus, Christian; Ast, Christian R; Morgenstern, Markus

2017-12-01

We present the design and calibration measurements of a scanning tunneling microscope setup in a 3 He ultrahigh-vacuum cryostat operating at 400 mK with a hold time of 10 days. With 2.70 m in height and 4.70 m free space needed for assembly, the cryostat fits in a one-story lab building. The microscope features optical access, an xy table, in situ tip and sample exchange, and enough contacts to facilitate atomic force microscopy in tuning fork operation and simultaneous magneto-transport measurements on the sample. Hence, it enables scanning tunneling spectroscopy on microstructured samples which are tuned into preselected transport regimes. A superconducting magnet provides a perpendicular field of up to 14 T. The vertical noise of the scanning tunneling microscope amounts to 1 pm rms within a 700 Hz bandwidth. Tunneling spectroscopy using one superconducting electrode revealed an energy resolution of 120 μeV. Data on tip-sample Josephson contacts yield an even smaller feature size of 60 μeV, implying that the system operates close to the physical noise limit.

An ultrahigh-vacuum cryostat for simultaneous scanning tunneling microscopy and magneto-transport measurements down to 400 mK

Science.gov (United States)

Liebmann, Marcus; Bindel, Jan Raphael; Pezzotta, Mike; Becker, Stefan; Muckel, Florian; Johnsen, Tjorven; Saunus, Christian; Ast, Christian R.; Morgenstern, Markus

2017-12-01

We present the design and calibration measurements of a scanning tunneling microscope setup in a 3He ultrahigh-vacuum cryostat operating at 400 mK with a hold time of 10 days. With 2.70 m in height and 4.70 m free space needed for assembly, the cryostat fits in a one-story lab building. The microscope features optical access, an xy table, in situ tip and sample exchange, and enough contacts to facilitate atomic force microscopy in tuning fork operation and simultaneous magneto-transport measurements on the sample. Hence, it enables scanning tunneling spectroscopy on microstructured samples which are tuned into preselected transport regimes. A superconducting magnet provides a perpendicular field of up to 14 T. The vertical noise of the scanning tunneling microscope amounts to 1 pmrms within a 700 Hz bandwidth. Tunneling spectroscopy using one superconducting electrode revealed an energy resolution of 120 μeV. Data on tip-sample Josephson contacts yield an even smaller feature size of 60 μeV, implying that the system operates close to the physical noise limit.

Scanning Laser Ophthalmoscope Measurement of Local Fundus Reflectance and Autofluorescence Changes Arising from Rhodopsin Bleaching and Regeneration

OpenAIRE

Morgan, Jessica I. W.; Pugh, Edward N.

2013-01-01

Rhodopsin was measured locally in the retina with a widely available, dual wavelength scanning laser ophthalmoscope that does not require pupil dilation. Increased autofluorescence attendant bleaching arises largely from transient removal of rhodopsin's screening of autofluorescent fluorochromes.

Scanning unit for collectrons

International Nuclear Information System (INIS)

Plaige, Yves.

1976-01-01

This invention concerns a measurement scanning assembly for collectron type detectors. It is used in measuring the neutron flux in nuclear reactors. As the number of these detectors in a reactor can be very great, they are not usually all connected permanently to the measuring facility but rather in turn by means of a scanning device which carries out, as it were, multiplexing between all the collectrons and the input of a single measuring system. The object of the invention is a scanning assembly which is of relative simplicity through an original organisation. Specifically, according to this organisation, the collectrons outputs are grouped together in bunches, each of these bunches being processed by a multiplexing sub-assembly belonging to a first stage, the different outputs of these multiplexing subassemblies of this first stage being grouped together yet again in bunches processed by multiplexors forming a new stage and so forth. Further, this structure is specially adapted for use with collectrons by utilising a current amplifier at each multiplexing level so that from one end to the other of the multiplexing system, the commutations are carried out on currents and not on voltages [fr

On-line slurry viscosity and concentration measurement as a real-time waste stream characterization tool. 1997 annual progress report

International Nuclear Information System (INIS)

Powell, R.L.

1997-01-01

'The main scope of this work is to: (1) develop a novel tomographic ultrasonic technique to obtain the real-time distribution of acoustic velocity and flow velocity; (2) use nuclear magnetic resonance imaging (NMRI) to measure velocity profiles and rheological properties of complex fluids and suspensions; (3) establish a facility for making laser Doppler velocimetry (LDV) measurements that can be The overall goal is to obtain real-time rheology and solids concentration within a solid-liquid suspension flowing in a pipeline. To nondestructively obtain the rheology of the fluid flowing in a pipe, accurate measurement of local shear rate distribution is required. This objective was met by using two real-time tomographic techniques: an ultrasonic Doppler velocimetry system and an NMRI system. The first method combines the existing state-of-the-art ultrasonic velocimetry technology base with a novel tomographic concept to non-intrusively obtain high resolution acoustic and flow velocity profile at a section of the flow field. The acoustic velocity profile provides a means of improving the flow velocity measurement accuracy. These data are also, used to yield the profile of solids concentration. In addition, the volumetric flow rate was determined from integration of the velocity profile. From the knowledge of the concentration profile the mass flow rate can also be determined, Similar work was undertaken for the NMNRI system. In this case, single phase Newtonian fluids have been used to model complex rheological behavior. Finally, a LDV system has been purchased and set - up in the laboratory at UC Davis.'

Confocal scanning microscopy with multiple optical probes for high speed measurements and better imaging

Science.gov (United States)

Chun, Wanhee; Lee, SeungWoo; Gweon, Dae-Gab

2008-02-01

Confocal scanning microscopy (CSM) needs a scanning mechanism because only one point information of specimen can be obtained. Therefore the speed of the confocal scanning microscopy is limited by the speed of the scanning tool. To overcome this limitation from scanning tool we propose another scanning mechanism. We make three optical probes in the specimen under confocal condition of each point. Three optical probes are moved by beam scanning mechanism with shared resonant scanning mirror (RM) and galvanometer driven mirror (GM). As each optical probe scan allocated region of the specimen, information from three points is obtained simultaneously and image acquisition time is reduced. Therefore confocal scanning microscopy with multiple optical probes is expected to have three times faster speed of the image acquisition than conventional one. And as another use, multiple optical probes to which different light wavelength is applied can scan whole same region respectively. It helps to obtain better contrast image in case of specimens having different optical characteristics for specific light wavelength. In conclusion confocal scanning microscopy with multiple optical probes is useful technique for views of image acquisition speed and image quality.

White light Z-scan measurements of ultrafast optical nonlinearity in reduced graphene oxide nanosheets in the 400–700 nm region

International Nuclear Information System (INIS)

Perumbilavil, Sreekanth; Sankar, Pranitha; Priya Rose, T.; Philip, Reji

2015-01-01

Wavelength dispersion of optical power limiting is an important factor to be considered while designing potential optical limiters for laser safety applications. We report the observation of broadband, ultrafast optical limiting in reduced graphene oxide (rGO), measured by a single open aperture Z-scan using a white light continuum (WLC) source. WLC Z-scan is fast when the nonlinearity is to be measured over broad wavelength ranges, and it obviates the need for an ultrafast tunable laser making it cost-economic compared to conventional Z-scan. The nonlinearity arises from nondegenerate two-photon absorption, owing mostly to the crystallinity and extended π conjugation of rGO

A quadruple-scanning-probe force microscope for electrical property measurements of microscopic materials

International Nuclear Information System (INIS)

Higuchi, Seiji; Kubo, Osamu; Kuramochi, Hiromi; Aono, Masakazu; Nakayama, Tomonobu

2011-01-01

Four-terminal electrical measurement is realized on a microscopic structure in air, without a lithographic process, using a home-built quadruple-scanning-probe force microscope (QSPFM). The QSPFM has four probes whose positions are individually controlled by obtaining images of a sample in the manner of atomic force microscopy (AFM), and uses the probes as contacting electrodes for electrical measurements. A specially arranged tuning fork probe (TFP) is used as a self-detection force sensor to operate each probe in a frequency modulation AFM mode, resulting in simultaneous imaging of the same microscopic feature on an insulator using the four TFPs. Four-terminal electrical measurement is then demonstrated in air by placing each probe electrode in contact with a graphene flake exfoliated on a silicon dioxide film, and the sheet resistance of the flake is measured by the van der Pauw method. The present work shows that the QSPFM has the potential to measure the intrinsic electrical properties of a wide range of microscopic materials in situ without electrode fabrication.

Effect of CT scanning parameters on volumetric measurements of pulmonary nodules by 3D active contour segmentation: a phantom study

International Nuclear Information System (INIS)

Way, Ted W; Chan, H-P; Goodsitt, Mitchell M; Sahiner, Berkman; Hadjiiski, Lubomir M; Zhou Chuan; Chughtai, Aamer

2008-01-01

The purpose of this study is to investigate the effects of CT scanning and reconstruction parameters on automated segmentation and volumetric measurements of nodules in CT images. Phantom nodules of known sizes were used so that segmentation accuracy could be quantified in comparison to ground-truth volumes. Spherical nodules having 4.8, 9.5 and 16 mm diameters and 50 and 100 mg cc -1 calcium contents were embedded in lung-tissue-simulating foam which was inserted in the thoracic cavity of a chest section phantom. CT scans of the phantom were acquired with a 16-slice scanner at various tube currents, pitches, fields-of-view and slice thicknesses. Scans were also taken using identical techniques either within the same day or five months apart for study of reproducibility. The phantom nodules were segmented with a three-dimensional active contour (3DAC) model that we previously developed for use on patient nodules. The percentage volume errors relative to the ground-truth volumes were estimated under the various imaging conditions. There was no statistically significant difference in volume error for repeated CT scans or scans taken with techniques where only pitch, field of view, or tube current (mA) were changed. However, the slice thickness significantly (p < 0.05) affected the volume error. Therefore, to evaluate nodule growth, consistent imaging conditions and high resolution should be used for acquisition of the serial CT scans, especially for smaller nodules. Understanding the effects of scanning and reconstruction parameters on volume measurements by 3DAC allows better interpretation of data and assessment of growth. Tracking nodule growth with computerized segmentation methods would reduce inter- and intraobserver variabilities

Value of duplex scanning compared with angiography and pressure measurement in the assessment of aortoiliac arterial lesions

NARCIS (Netherlands)

Legemate, D. A.; Teeuwen, C.; Hoeneveld, H.; Eikelboom, B. C.

1991-01-01

To detect haemodynamically significant lesions in the aortoiliac arteries, invasive tests such as angiography and intra-arterial pressure measurement (IAPM) are considered valuable diagnostic tools. The value of duplex scanning as a direct non-invasive examination technique was prospectively

Reducing radiation dose in liver enhanced CT scan by setting mAs according to plain scan noise

International Nuclear Information System (INIS)

Yang Shangwen; He Jian; Yang Xianfeng; Zhou Kefeng; Xin Xiaoyan; Hu Anning; Zhu Bin

2013-01-01

Objective: To investigate the feasibility of setting mAs in liver enhanced CT scan according to plain scan noise with fixed mA CT scanner, in order to reduce the radiation dose. Methods: One hundred continuous patients underwent liver enhanced CT scan (group A) prospectively. Two hundred and fifty mAs was used in plain and enhanced CT scans. Noises of plain and venous phase CT images were measured, and the image quality was evaluated. The equation between mAs of enhanced scan and noise of plain scan image was derived. Another 100 continuous patients underwent liver enhanced CT scan (group B). Enhanced scan mAs was calculated from noise on plain scan by using the equation above. Noises on venous phase images were measured and the image quality was measured. Based on body mass index (BMI), patients in groups A and B were divided into three subgroups respectively: BMI < 18.5 kg/m 2 , 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 and BMI ≥ 25.0 kg/m 2 . Image quality score was compared with nonparametric rank sum test, CT dose index (CTDI) and effective dose (ED) were measured and compared between each subgroup with 2 independent samples t or t' test. Results: The equation between enhanced scan mAs (mAsX) and plain scan noise (SDp) was as follows: mAsX = mAs1 × [(0.989 × SDp + 1.06) /SDx] 2 , mAs1 = 250 mAs, SDx = 13. In patients with BMI < 18.5 kg/m 2 , ED of group A [(6.86 ± 0.38) mSv, n = 12] was significantly higher than group B [(2.66 ± 0.46) mSv, n = 10)] (t = 18.52, P < 0.01). In patients with 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 , ED of group A [(7.08 ± 0.91) mSv, n = 66] was significantly higher than group B [(4.50 ± 1.41) mSv, n = 73] (t' = 10.57, P < 0.01). In patients with BMI ≥ 25.0 kg/m 2 , there was no significant difference between EDs of group A (7.54 ± 0.62 mSv, n = 22) and group B [(8.19 ± 3.16) mSv, n = 17] (t' = 0.89, P = 0.39). Image quality of 5 patients in group A and none in group B did not meet the diagnostic requirement

CT-scan-monitored electrical resistivity measurements show problems achieving homogeneous saturation

International Nuclear Information System (INIS)

Sprunt, E.S.; Coles, M.E.; Davis, R.M.; Muegge, E.L.; Desai, K.P.

1991-01-01

X-ray CT scans obtained during measurement of the electrical resistivity of core samples revealed some problems in obtaining uniform saturation along the length of the sample. In this paper the electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent, which is used in electric log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone. A stationary front formed in one sample at 1 psi oil/brine capillary pressure. A moving front formed at oil/brine capillary pressures of 4 psi or less in both samples tested, in both a fresh mixed-wettability state and in a cleaned water-wet state. In these samples, the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated

A scanning contact probe for a micro-coordinate measuring machine (CMM)

International Nuclear Information System (INIS)

Fan, Kuang-Chao; Cheng, Fang; Wang, Weili; Chen, Yejin; Lin, Jia-You

2010-01-01

A new high precision contact scanning probe able to measure miniature components on a micro/nano-coordinate measuring machine (CMM) is proposed. This contact probe is composed of a fiber stylus with a ball tip, a floating plate and focus sensors. The stylus is attached to a floating plate, which is connected to the probe housing via four elastic wires. When the probe tip is touched and then deflected by the workpiece, the wires experience elastic deformations and the four mirrors mounted on the plate will be displaced. These displacements can be detected by four corresponding laser focus probes. To calibrate this touch trigger probe, a double-trigger method is developed for a high-speed approach and a low-speed touch. Experimental results show that the probe has a symmetric contact property in the horizontal XY plane. The contact force is found to be about 109 µN. The standard deviation of the unidirectional touch is less than 10 nm and the pre-travel distance is around 10 nm with a standard deviation of less than 3 nm

Microscopic measurement of penetration depth in YBa2Cu3O7-δ thin films by scanning Hall probe microscopy

International Nuclear Information System (INIS)

Oral, A.; Bending, S.J.; Humphreys, R.G.; Henini, M.

1997-01-01

We have used a low noise scanning Hall probe microscope to measure the penetration depth microscopically in a YBa 2 Cu 3 O 7-δ thin film as a function of temperature. The instrument has high magnetic field (approx. 2.9x10 -8 T Hz -1/2 at 77 K) and spatial resolution (approx. 0.85 μm). Magnetic field profiles of single vortices in the superconducting film have been successfully measured and the microscopic penetration depth of the superconductor has been extracted. We find surprisingly large variations in values of λ for different vortices within the scanning field. (author)

CT head-scan dosimetry in an anthropomorphic phantom and associated measurement of ACR accreditation-phantom imaging metrics under clinically representative scan conditions

Energy Technology Data Exchange (ETDEWEB)

Brunner, Claudia C.; Stern, Stanley H.; Chakrabarti, Kish [U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States); Minniti, Ronaldo [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Parry, Marie I. [Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, Maryland 20889 (United States); Skopec, Marlene [National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892 (United States)

2013-08-15

Purpose: To measure radiation absorbed dose and its distribution in an anthropomorphic head phantom under clinically representative scan conditions in three widely used computed tomography (CT) scanners, and to relate those dose values to metrics such as high-contrast resolution, noise, and contrast-to-noise ratio (CNR) in the American College of Radiology CT accreditation phantom.Methods: By inserting optically stimulated luminescence dosimeters (OSLDs) in the head of an anthropomorphic phantom specially developed for CT dosimetry (University of Florida, Gainesville), we measured dose with three commonly used scanners (GE Discovery CT750 HD, Siemens Definition, Philips Brilliance 64) at two different clinical sites (Walter Reed National Military Medical Center, National Institutes of Health). The scanners were set to operate with the same data-acquisition and image-reconstruction protocols as used clinically for typical head scans, respective of the practices of each facility for each scanner. We also analyzed images of the ACR CT accreditation phantom with the corresponding protocols. While the Siemens Definition and the Philips Brilliance protocols utilized only conventional, filtered back-projection (FBP) image-reconstruction methods, the GE Discovery also employed its particular version of an adaptive statistical iterative reconstruction (ASIR) algorithm that can be blended in desired proportions with the FBP algorithm. We did an objective image-metrics analysis evaluating the modulation transfer function (MTF), noise power spectrum (NPS), and CNR for images reconstructed with FBP. For images reconstructed with ASIR, we only analyzed the CNR, since MTF and NPS results are expected to depend on the object for iterative reconstruction algorithms.Results: The OSLD measurements showed that the Siemens Definition and the Philips Brilliance scanners (located at two different clinical facilities) yield average absorbed doses in tissue of 42.6 and 43.1 m

LDV measurement of small nonlinearities in flat and curved membranes. A model for eardrum nonlinear acoustic behaviour

Science.gov (United States)

Kilian, Gladiné; Pieter, Muyshondt; Joris, Dirckx

2016-06-01

Laser Doppler Vibrometry is an intrinsic highly linear measurement technique which makes it a great tool to measure extremely small nonlinearities in the vibration response of a system. Although the measurement technique is highly linear, other components in the experimental setup may introduce nonlinearities. An important source of artificially introduced nonlinearities is the speaker, which generates the stimulus. In this work, two correction methods to remove the effects of stimulus nonlinearity are investigated. Both correction methods were found to give similar results but have different pros and cons. The aim of this work is to investigate the importance of the conical shape of the eardrum as a source of nonlinearity in hearing. We present measurements on flat and indented membranes. The data shows that the curved membrane exhibit slightly higher levels of nonlinearity compared to the flat membrane.

Post-PRK corneal scatter measurements with a scanning confocal slit photon counter

Science.gov (United States)

Taboada, John; Gaines, David; Perez, Mary A.; Waller, Steve G.; Ivan, Douglas J.; Baldwin, J. Bruce; LoRusso, Frank; Tutt, Ronald C.; Perez, Jose; Tredici, Thomas; Johnson, Dan A.

2000-06-01

Increased corneal light scatter or 'haze' has been associated with excimer laser photorefractive surgery of the cornea. The increased scatter can affect visual performance; however, topical steroid treatment post surgery substantially reduces the post PRK scatter. For the treatment and monitoring of the scattering characteristics of the cornea, various methods have been developed to objectively measure the magnitude of the scatter. These methods generally can measure scatter associated with clinically observable levels of haze. For patients with moderate to low PRK corrections receiving steroid treatment, measurement becomes fairly difficult as the haze clinical rating is non observable. The goal of this development was to realize an objective, non-invasive physical measurement that could produce a significant reading for any level including the background present in a normal cornea. As back-scatter is the only readily accessible observable, the instrument is based on this measurement. To achieve this end required the use of a confocal method to bias out the background light that would normally confound conventional methods. A number of subjects with nominal refractive errors in an Air Force study have undergone PRK surgery. A measurable increase in corneal scatter has been observed in these subjects whereas clinical ratings of the haze were noted as level zero. Other favorable aspects of this back-scatter based instrument include an optical capability to perform what is equivalent to an optical A-scan of the anterior chamber. Lens scatter can also be measured.

Impact of measurement approach on the quality of gamma scanning density profile in a tray type lab-scale column

International Nuclear Information System (INIS)

Shahabinejad, H.; Feghhi, S.A.H.; Khorsandi, M.

2014-01-01

This article presents a study for investigating impact of the measurement approach on the quality of gamma scanning density profile in tray type columns using experimental and computational evaluations. Experimental density profiles from the total and the photopeak count measurements, as two approaches in gamma ray column scanning technique, has been compared with the computational density profile from Monte Carlo simulation results. We used a laboratory distillation column of 51 cm diameter as an illustrative example for this investigation. 137 Cs was used as a gamma ray source with the activity of 296 MBq (8 mCi), with a NaI(Tl) detector. MCNP4C Monte Carlo code has been used for simulations. The quality of the density profile in the photopeak count approach is relatively within 155–204% better than that of the total count approach for experimental results. The same comparison for simulation results leads to a relative difference within 100–135% for the density profile. - Highlights: • The quality of density profile in gamma scanning technique has been studied. • Quality of density profile depends on the measurement approach. • A laboratory distillation column has been used as an illustrative example. • MCNP4C Monte Carlo code has been used for simulations

Apoplastic pH in corn root gravitropism: a laser scanning confocal microscopy measurement

International Nuclear Information System (INIS)

Taylor, D.P.; Slattery, J.; Leopold, A.C.

1996-01-01

The ability to measure the pH of the apoplast in situ is of special interest as a test of the cell wall acidification theory. Optical sectioning of living seedlings of corn roots using the laser scanning confocal microscope (LSCM) permits us to make pH measurements in living tissue. The pH of the apoplast of corn roots was measured by this method after infiltration with CI-NERF, a pH-sensitive dye, along with Texas Red Dextran 3000, a pH-insensitive dye, as an internal standard. In the elongation zone of corn roots, the mean apoplastic pH was 4.9. Upon gravitropic stimulation, the pH on the convex side of actively bending roots was 4.5. The lowering of the apoplastic pH by 0.4 units appears to be sufficient to account for the increased growth on that side. This technique provides site-specific evidence for the acid growth theory of cell elongation. The LSCM permits measurements of the pH of living tissues, and has a sensitivity of approximately 0.2 pH units. (author)

Subtropical Cirrus Properties Derived from GSFC Scanning Raman Lidar Measurements during CAMEX 3

Science.gov (United States)

Whiteman, D. N.; Wang, Z.; Demoz, B.

2004-01-01

The NASA/GSFC Scanning Raman Lidar (SRL) was stationed on Andros Island, Bahamas for the third Convection and Moisture Experiment (CAMEX 3) held in August - September, 1998 and acquired an extensive set of water vapor and cirrus cloud measurements (Whiteman et al., 2001). The cirrus data studied here have been segmented by generating mechanism. Distinct differences in the optical properties of the clouds are found when the cirrus are hurricane-induced versus thunderstom-induced. Relationships of cirrus cloud optical depth, mean cloud temperature, and layer mean extinction-to-backscatter ratio (S) are presented and compared with mid-latitude and tropical results. Hurricane-induced cirrus clouds are found to generally possess lower values of S than thunderstorm induced clouds. Comparison of these measurements of S are made with other studies revealing at times large differences in the measurements. Given that S is a required parameter for spacebased retrievals of cloud optical depth using backscatter lidar, these large diffaences in S measurements present difficulties for space-based retrievals of cirrus cloud extinction and optical depth.

Paediatric renal length measurements from ultrasound and DMSA scans: does clinical practice reflect theoretical normal values?

International Nuclear Information System (INIS)

Que, L.; Rutland, M.D.; Hassan, I.M.

1999-01-01

Full text: Renal length measurement is a routine part of ultrasound examination in children and those results are plotted on a normogram style graph, so that each child's results are compared to a normal range (mean ± 2 S.D.). Renal length measurements from the posterior oblique views of dimercaptosuccinic acid (DMSA) scans in our department have not always correlated well with the ultrasound measurements on the same patients. Renal lengths from the DMSA scans of 120 patients with apparently normal kidneys were recorded and used to generate a normogram of renal length at different ages (0.5-7 years). This DMSA normogram was compared to the ultrasound (US) normogram used in the Paediatric Radiology Department, and it showed slight differences in renal lengths (3-8 mm), but that the US normogram had smaller coefficients of variation (US = 6.6%, NM 8.3%), implying a 'tighter' normal range. 39 of these patients had DMSA and ultrasound measurements of renal length within 3 months, and these were studied first by calculating the mean and CV values for different age groups, and then by plotting individual renal lengths on the appropriate normograms. The measured data produced much greater variability in the ultrasound measurements than the DTPA measurements, and the individual points produced 4/78 (5.1%) abnormal results for DMSA, but 21/78 (26.9%) abnormal results for ultrasound. Thus, in routine clinical use, using patients with apparently normal kidneys, ultrasound was unable to match the 'normal range' set by their current normogram, but the nuclear medicine showed 5.1% of values outside the normal (DMSA) range, which was completely appropriate for a range of ± 2 standard deviations

An Evaluation of pectus excavatum by means of body surface measurements on chest CT scans

International Nuclear Information System (INIS)

Hirotani, Taichi; Ohama, Kazunori; Shimotake, Takashi; Ishikawa, Nobuki; Watanabe, Reiji

2009-01-01

The aim of this study is to determine whether the body surface index replaces the Haller index in order to evaluate the severity of pectus excavatum. Sixty-nine cases with a diagnosis of pectus excavatum between August 2001 and January 2008 were prospectively enrolled in the study. The anterior-posterior chest dimension, lateral chest dimension and depth of the most profound depressed area were measured. The body surface index was expressed as an equation A/(B-C), where A was the transverse diameter, B was the anterior-posterior diameter and C was the depth of the depressed area. This index was compared to the Haller index in each patient. In this study, each value was measured on a chest CT scan. The body surface index significantly correlated with the Haller index, in which the coefficient of correlation was 0.879 (p<0.01). The body surface index corresponding to Haller index 3.25 seems to be 1.67. We could find the body surface index corresponding to each Haller index. We propose that an evaluation of pectus excavatum by means of body surface measurements is clinically useful, and may replace the Haller index. The body surface index may allow us to assess the severity of pectus excavatum without a CT scan, resulting in a reduction of radiation exposure for children with pectus excavatum. It's possible to evaluate the body surface index by using a relational table between this index and the Hailer index. We'll evaluate the body surface index by using values measured on a real body. (author)

Modeling laser velocimeter signals as triply stochastic Poisson processes

Science.gov (United States)

Mayo, W. T., Jr.

1976-01-01

Previous models of laser Doppler velocimeter (LDV) systems have not adequately described dual-scatter signals in a manner useful for analysis and simulation of low-level photon-limited signals. At low photon rates, an LDV signal at the output of a photomultiplier tube is a compound nonhomogeneous filtered Poisson process, whose intensity function is another (slower) Poisson process with the nonstationary rate and frequency parameters controlled by a random flow (slowest) process. In the present paper, generalized Poisson shot noise models are developed for low-level LDV signals. Theoretical results useful in detection error analysis and simulation are presented, along with measurements of burst amplitude statistics. Computer generated simulations illustrate the difference between Gaussian and Poisson models of low-level signals.

3D shape measurement for moving scenes using an interlaced scanning colour camera

International Nuclear Information System (INIS)

Cao, Senpeng; Cao, Yiping; Lu, Mingteng; Zhang, Qican

2014-01-01

A Fourier transform deinterlacing algorithm (FTDA) is proposed to eliminate the blurring and dislocation of the fringe patterns on a moving object captured by an interlaced scanning colour camera in phase measuring profilometry (PMP). Every frame greyscale fringe from three colour channels of every colour fringe is divided into even and odd field fringes respectively, each of which is respectively processed by FTDA. All of the six frames deinterlaced fringes from one colour fringe form two sets of three-step phase-shifted greyscale fringes, with which two 3D shapes corresponding to two different moments are reconstructed by PMP within a frame period. The deinterlaced fringe is identical with the exact frame fringe at the same moment theoretically. The simulation and experiments show its feasibility and validity. The method doubles the time resolution, maintains the precision of the traditional phase measurement profilometry, and has potential applications in the moving and online object’s 3D shape measurements. (paper)

Microscopic image processing system for measuring nonuniform film thickness profiles: Image scanning ellipsometry

International Nuclear Information System (INIS)

Liu, A.H.; Plawsky, J.L.; Wayner, P.C. Jr.

1993-01-01

The long-term objective of this research program is to determine the stability and heat transfer characteristics of evaporating thin films. The current objective is to develop and use a microscopic image-processing system (IPS) which has two parts: an image analyzing interferometer (IAI) and an image scanning ellipsometer (ISE). The primary purpose of this paper is to present the basic concept of ISE, which is a novel technique to measure the two dimensional thickness profile of a non-uniform, thin film, from several nm up to several μm, in a steady state as well as in a transient state. It is a full-field imaging technique which can study every point on the surface simultaneously with high spatial resolution and thickness sensitivity, i.e., it can measure and map the 2-D film thickness profile. The ISE was tested by measuring the thickness profile and the refractive index of a nonuniform solid film

Cloud fraction and cloud base measurements from scanning Doppler lidar during WFIP-2

Science.gov (United States)

Bonin, T.; Long, C.; Lantz, K. O.; Choukulkar, A.; Pichugina, Y. L.; McCarty, B.; Banta, R. M.; Brewer, A.; Marquis, M.

2017-12-01

The second Wind Forecast Improvement Project (WFIP-2) consisted of an 18-month field deployment of a variety of instrumentation with the principle objective of validating and improving NWP forecasts for wind energy applications in complex terrain. As a part of the set of instrumentation, several scanning Doppler lidars were installed across the study domain to primarily measure profiles of the mean wind and turbulence at high-resolution within the planetary boundary layer. In addition to these measurements, Doppler lidar observations can be used to directly quantify the cloud fraction and cloud base, since clouds appear as a high backscatter return. These supplementary measurements of clouds can then be used to validate cloud cover and other properties in NWP output. Herein, statistics of the cloud fraction and cloud base height from the duration of WFIP-2 are presented. Additionally, these cloud fraction estimates from Doppler lidar are compared with similar measurements from a Total Sky Imager and Radiative Flux Analysis (RadFlux) retrievals at the Wasco site. During mostly cloudy to overcast conditions, estimates of the cloud radiating temperature from the RadFlux methodology are also compared with Doppler lidar measured cloud base height.

Analysis of classical guitars' vibrational behavior based on scanning laser vibrometer measurements

Science.gov (United States)

Czajkowska, Marzena

2012-06-01

One of the main goals in musical acoustics research is to link measurable, physical properties of a musical instrument with subjective assessments of its tone quality. The aim of the research discussed in this paper was to observe the structural vibrations of different class classical guitars in relation to their quality. This work focuses on mid-low-and low-class classical (nylon-stringed) guitars. The main source of guitar body vibrations come from top and back plate vibrations therefore these were the objects of structural mode measurements and analysis. Sixteen classical guitars have been investigated, nine with cedar and seven with spruce top plate. Structural modes of top and back plates have been measured with the aid of a scanning laser vibrometer and the instruments were excited with a chirp signal transferred by bone vibrator. The issues related to excitor selection have been discussed. Correlation and descriptive statistics of top and back plates measurement results have been investigated in relation to guitar quality. The frequency range of 300 Hz to 5 kHz as well as selected narrowed frequency bands have been analyzed for cedar and spruce guitars. Furthermore, the influence of top plate wood type on vibration characteristics have been observed on three pairs of guitars. The instruments were of the same model but different top plate material. Determination and visualization of both guitar plates' modal patterns in relation to frequency are a significant attainment of the research. Scanning laser vibrometer measurements allow particular mode observation and therefore mode identification, as opposed to sound pressure response measurements. When correlating vibration characteristics of top and back plates it appears that Pearson productmoment correlation coefficient is not a parameter that associates with guitar quality. However, for best instruments with cedar top, top-back correlation coefficient has relatively greater value in 1-2 kHz band and lower in

Comparison of 3D laser-based photonic scans and manual anthropometric measurements of body size and shape in a validation study of 123 young Swiss men

Directory of Open Access Journals (Sweden)

Nikola Koepke

2017-02-01

Full Text Available Background Manual anthropometric measurements are time-consuming and challenging to perform within acceptable intra- and inter-individual error margins in large studies. Three-dimensional (3D laser body scanners provide a fast and precise alternative: within a few seconds the system produces a 3D image of the body topography and calculates some 150 standardised body size measurements. Objective The aim was to enhance the small number of existing validation studies and compare scan and manual techniques based on five selected measurements. We assessed the agreement between two repeated measurements within the two methods, analysed the direct agreement between the two methods, and explored the differences between the techniques when used in regressions assessing the effect of health related determinants on body shape indices. Methods We performed two repeated body scans on 123 volunteering young men using a Vitus Smart XXL body scanner. We manually measured height, waist, hip, buttock, and chest circumferences twice for each participant according to the WHO guidelines. The participants also filled in a basic questionnaire. Results Mean differences between the two scan measurements were smaller than between the two manual measurements, and precision as well as intra-class correlation coefficients were higher. Both techniques were strongly correlated. When comparing means between both techniques we found significant differences: Height was systematically shorter by 2.1 cm, whereas waist, hip and bust circumference measurements were larger in the scans by 1.17–4.37 cm. In consequence, body shape indices also became larger and the prevalence of overweight was greater when calculated from the scans. Between 4.1% and 7.3% of the probands changed risk category from normal to overweight when classified based on the scans. However, when employing regression analyses the two measurement techniques resulted in very similar coefficients, confidence

Measurements of lateral penumbra for uniform scanning proton beams under various beam delivery conditions and comparison to the XiO treatment planning system

International Nuclear Information System (INIS)

Rana, Suresh; Zeidan, Omar; Ramirez, Eric; Rains, Michael; Gao, Junfang; Zheng, Yuanshui

2013-01-01

Purpose: The main purposes of this study were to (1) investigate the dependency of lateral penumbra (80%–20% distance) of uniform scanning proton beams on various factors such as air gap, proton range, modulation width, compensator thickness, and depth, and (2) compare the lateral penumbra calculated by a treatment planning system (TPS) with measurements.Methods: First, lateral penumbra was measured using solid–water phantom and radiographic films for (a) air gap, ranged from 0 to 35 cm, (b) proton range, ranged from 8 to 30 cm, (c) modulation, ranged from 2 to 10 cm, (d) compensator thickness, ranged from 0 to 20 cm, and (e) depth, ranged from 7 to 15 cm. Second, dose calculations were computed in a virtual water phantom using the XiO TPS with pencil beam algorithm for identical beam conditions and geometrical configurations that were used for the measurements. The calculated lateral penumbra was then compared with the measured one for both the horizontal and vertical scanning magnets of our uniform scanning proton beam delivery system.Results: The results in the current study showed that the lateral penumbra of horizontal scanning magnet was larger (up to 1.4 mm for measurement and up to 1.0 mm for TPS) compared to that of vertical scanning magnet. Both the TPS and measurements showed an almost linear increase in lateral penumbra with increasing air gap as it produced the greatest effect on lateral penumbra. Lateral penumbra was dependent on the depth and proton range. Specifically, the width of lateral penumbra was found to be always lower at shallower depth than at deeper depth within the spread out Bragg peak (SOBP) region. The lateral penumbra results were less sensitive to the variation in the thickness of compensator, whereas lateral penumbra was independent of modulation. Overall, the comparison between the results of TPS with that of measurements indicates a good agreement for lateral penumbra, with TPS predicting higher values compared to

SU-F-T-173: One-Scan Protocol: Verifying the Delivery of Spot-Scanning Proton Beam

Energy Technology Data Exchange (ETDEWEB)

Chan, M; Li, J [Memorial Sloan-Kettering Cancer Center, Basking Ridge, NJ (United States); Chen, C; Mah, D [Procure Treatment Center, Somerset, NJ (United States); Tang, X [Memorial Sloan Kettering Cancer Center, West Harrison, NY (United States); Li, X [Memorial Sloan Kettering Cancer Center, Rockville Centre, NY (United States); Tang, G [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

2016-06-15

Purpose: Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread use. Moreover, since there may be an energy dependence, which manifests as a depth dependence, this may require additional measurements for each patient. We present a one-scan protocol to simplify the procedure. Methods: We performed the calibration using an EBT3 film at depths of 18, 20, 24cm of Plastic Water exposed by a 6-level step-wedge plan on a Proteus Plus proton system (IBA, Belgium). The calibration doses ranged 65–250 cGy(RBE) for proton energies of 170–200MeV. A clinical prostate+nodes plan was used for validation. The planar doses at selected depths were measured with EBT3 films and analyzed using one-scan protocol (one-scan digitization of QA film and at least one film exposed to known dose). The Gamma passing rates, dose-difference maps, and profiles of 2D planar doses measured with EBT3 film, IBA MatriXX PT, versus TPS calculations were analyzed and compared. Results: The EBT3 film measurement results matched well with the TPS calculation data with an average passing rate of ∼95% for 2%/2mm and slightly lower passing rates were obtained from an ion chamber array detector. We were able to demonstrate that the use of a proton step-wedge provided clinically acceptable results and minimized variations between film-scanner orientation, inter-scan, and scanning conditions. Furthermore, it could be derived from no more than two films exposed to known doses (one could be zero) for rescaling the master calibration curve at each depth. Conclusion: The use of a proton step-wedge for calibration of EBT3 film increases efficiency. The sensitivity of the calibration to depth variations has been explored. One-scan protocol results appear to be comparable to that of the ion chamber array detector. One author has a research grant from

The use of spectral skin reflectivity and laser doppler vibrometry data to determine the optimal site and wavelength to collect human vital sign signatures

Science.gov (United States)

Byrd, Kenneth A.; Kaur, Balvinder; Hodgkin, Van A.

2012-06-01

The carotid artery has been used extensively by researchers to demonstrate that Laser Doppler Vibrometry (LDV) is capable of exploiting vital sign signatures from cooperative human subjects at stando. Research indicates that, the carotid, although good for cooperative and non-traumatic scenarios, is one of the first vital signs to become absent or irregular when a casualty is hemorrhaging and in progress to circulatory (hypovolemic) shock. In an effort to determine the optimal site and wavelength to measure vital signs off human skin, a human subject data collection was executed whereby 14 subjects had their spectral skin reflectivity and vital signs measured at five collection sites (carotid artery, chest, back, right wrist and left wrist). In this paper, we present our findings on using LDV and re ectivity data to determine the optimal collection site and wavelength that should be used to sense pulse signals from quiet and relatively motionless human subjects at stando. In particular, we correlate maximum levels of re ectivity across the ensemble of 14 subjects with vital sign measurements made with an LDV at two ranges, for two scenarios.

G-scan--mobile multiview 3-D measuring system for the analysis of the face.

Science.gov (United States)

Kopp, S; Kühmstedt, P; Notni, G; Geller, R

2003-10-01

The development of optical 3-D measuring techniques and their use in industrial quality assurance, in design, and for rapid prototyping has experienced strong growth. A large number of optical 3-D measuring methods and systems are on the market in dentistry. CAD/CAM production has become firmly established in dental medicine, not least due to the systematic introduction of the Cerec technique and the digiDent method. The scanners on which these technologies are based are designed for a relatively small measuring area. To be able to measure and three-dimensionally assess the face--and the numerous changes in the face/forehead/neck region--it was necessary to design and develop a self-calibrating measuring system with gray code for clinical use: the G-Scan measuring system. Objects up to a size of 500 x 500 x 400 mm can be acquired three-dimensionally with it, with a measuring inaccuracy of 10 to 70 microm in a typical measuring time of 15 s. The present article describes the measuring principle, the system parameters, and the features of the new measuring system, and illustrates the measuring results on 3-D displays of the face in static occlusion and in functional occlusion positions.

Quantitative Method to Measure Thermal Conductivity of One-Dimensional Nanostructures Based on Scanning Thermal Wave Microscopy

Energy Technology Data Exchange (ETDEWEB)

Park, Kyung Bae; Chung, Jae Hun; Hwang, Gwang Seok; Jung, Eui Han; Kwon, Oh Myoung [Korea University, Seoul (Korea, Republic of)

2014-12-15

We present a method to quantitatively measure the thermal conductivity of one-dimensional nanostructures by utilizing scanning thermal wave microscopy (STWM) at a nanoscale spatial resolution. In this paper, we explain the principle for measuring the thermal diffusivity of one-dimensional nanostructures using STWM and the theoretical analysis procedure for quantifying the thermal diffusivity. The SWTM measurement method obtains the thermal conductivity by measuring the thermal diffusivity, which has only a phase lag relative to the distance corresponding to the transferred thermal wave. It is not affected by the thermal contact resistances between the heat source and nanostructure and between the nanostructure and probe. Thus, the heat flux applied to the nanostructure is accurately obtained. The proposed method provides a very simple and quantitative measurement relative to conventional measurement techniques.

Noise suppression in curved glass shells using macro-fiber-composite actuators studied by the means of digital holography and acoustic measurements

Directory of Open Access Journals (Sweden)

P. Mokrý

2015-02-01

Full Text Available The paper presents methods and experimental results of the semi-active control of noise transmission in a curved glass shell with attached piezoelectric macro fiber composite (MFC actuators. The semi-active noise control is achieved via active elasticity control of piezoelectric actuators by connecting them to an active electric shunt circuit that has a negative effective capacitance. Using this approach, it is possible to suppress the vibration of the glass shell in the normal direction with respect to its surface and to increase the acoustic transmission loss of the piezoelectric MFC-glass composite structure. The effect of the MFC actuators connected to the negative capacitance shunt circuit on the surface distribution of the normal vibration amplitude is studied using frequency-shifted digital holography (FSDH. The principle of the used FSDH method is described in the paper. The frequency dependence of the acoustic transmission loss through the piezoelectric MFC-glass composite structure is estimated using measurements of the specific acoustic impedance of the curved glass shell. The specific acoustic impedance is measured using two microphones and a laser Doppler vibrometer (LDV. The results from the LDV measurements are compared with the FSDH data. The results of the experiments show that using this approach, the acoustic transmission loss in a glass shell can be increased by 36 dB in the frequency range around 247 Hz and by 25 dB in the frequency range around 258 Hz. The experiments indicate that FSDH measurements provide an efficient tool that can be used for fast and accurate measurements of the acoustic transmission loss in large planar structures.

Analyzing Protein Denaturation using Fast Differential Scanning Calorimetry

NARCIS (Netherlands)

Splinter, R.; Van Herwaarden, A.W.; Iervolino, E.; Vanden Poel, G.; Istrate, D.; Sarro, P.M.

2012-01-01

This paper investigates the possibility to measure protein denaturation with Fast Differential Scanning Calorimetry (FDSC). Cancer can be diagnosed by measuring protein denaturation in blood plasma using Differential Scanning Calorimetry (DSC). FDSC can reduce diagnosis time from hours to minutes,

Application of optical scanning for measurements of castings and cores

Directory of Open Access Journals (Sweden)

M. Wieczorowski

2010-01-01

Full Text Available In the paper application of non destructive method for dimensional control of elements in initial phase of car manufacturing, at Volks-wagen Poznań foundry was presented. VW foundry in Poznań is responsible of series production of chill and dies castings made of light alloys using contemporary technologies. Castings have a complex shape: they are die castings of housings for steering columns and gravity chill castings of cylinder heads, for which cores are manufactured using both hot box and cold box method. Manufacturing capabilities of VW foundry in Poznań reach 26.000 tons of aluminum castings per year. Optical system ATOS at Volkswagen Poznań foundry is used to digitize object and determination of all dimensions and shapes of inspected object. This technology is applied in car industry, reverse engineering, quality analysis and control and to solve many similar tasks. System is based on triangulation: sensor head projects different fringes patterns onto a measured object while scanner observes their trajectories using two cameras. Basing on optical transform equations a processing unit automatically and with a great accuracy calculates 3D coordinates for every pixel of camera. Depending on camera reso-lution as an effect of such a scan we obtain a cloud of up to 4 million points for every single measurement. In the paper examples of di-mensional analysis regarding castings and cores were presented.

RisøScan - a new dosimetry software

DEFF Research Database (Denmark)

Helt-Hansen, J.; Miller, A.

2004-01-01

RisoScan is a software package that is used for analysis of images of visibly coloured dosimeter films. The image is created by scanning the dosimeter film on a flatbed scanner. RisoScan is based on LabView(R), and it is useful for analysis of dose distributions and depth dose curves. Measurement...

Development of a New Radiation Measuring Instrument for the Column Scanning Technique - NibraS

International Nuclear Information System (INIS)

Benahmed, A.; Alami, R.

2013-06-01

The radiation measuring instrument, called Nibras, associated to a special data processing software for Column scanning is a new data acquisition system. It was developed to scan and to plot density profiles, inside a distillation column, which illustrates the activity of the radiations able to cross the contents of the column. Nibras is an autonomous data logger with very low power consumption, using only 4 batteries of 1.5 V and can be operated for more than 120 hours continuously; this presents an ecological and economic importance. Another particularity of Nibras consists in its dual functionality to display counting rates indicating the existence and the intensity of radiation; and to perform a real-time control in industrial plant particularly in oil distillation columns, due to its user-friendly software. This last provides essential data to optimize the performance of the columns, extend column run times, track the performance-deteriorating effects of fouling and solids deposition, and to identify maintenance requirements well in advance of scheduled turnarounds. This on-line knowledge can reduce repair downtime significantly. (authors)

Measurement of the relative power density distribution of the IPEN/MB-01 reactor, using a fuel rod gamma scanning technique

International Nuclear Information System (INIS)

Carneiro, Alvaro Luiz Guimaraes

1996-01-01

This work presents a measurement methodology for determination of radial and axial relative power density distribution of the IPEN/MB-01 Reactor core by means of the fuel rod gamma scanning. The methodology is based on the proportionality between gamma activity emitted by the radioactive decay of the fission products and power density. The scanning technique consists of counting gamma radiation above 0,6 MeV along the active area of the fuel rod, getting a distribution profile. The experimental results will be used as a benchmark for qualification and to establish possible deviations for the calculational methodology currently used at IPEN. The comparison of the calculated and measured results showed good agreement. (author)

Laser Scanning in Forests

Directory of Open Access Journals (Sweden)

Håkan Olsson

2012-09-01

Full Text Available The introduction of Airborne Laser Scanning (ALS to forests has been revolutionary during the last decade. This development was facilitated by combining earlier ranging lidar discoveries [1–5], with experience obtained from full-waveform ranging radar [6,7] to new airborne laser scanning systems which had components such as a GNSS receiver (Global Navigation Satellite System, IMU (Inertial Measurement Unit and a scanning mechanism. Since the first commercial ALS in 1994, new ALS-based forest inventory approaches have been reported feasible for operational activities [8–12]. ALS is currently operationally applied for stand level forest inventories, for example, in Nordic countries. In Finland alone, the adoption of ALS for forest data collection has led to an annual savings of around 20 M€/year, and the work is mainly done by companies instead of governmental organizations. In spite of the long implementation times and there being a limited tradition of making changes in the forest sector, laser scanning was commercially and operationally applied after about only one decade of research. When analyzing high-ranked journal papers from ISI Web of Science, the topic of laser scanning of forests has been the driving force for the whole laser scanning research society over the last decade. Thus, the topic “laser scanning in forests” has provided a significant industrial, societal and scientific impact. [...

Made-to-measure pattern development based on 3D whole body scans

NARCIS (Netherlands)

Daanen, H.; Hong, S.A.

2008-01-01

Purpose - New techniques are required to link 3D whole body scans to manufacturing techniques to allow for the mass-customization of clothes. This study aims to compare two methods of producing skirts based on 3D whole body scans. Design/methodology/approach - Three females participated in the

Water vapor retrieval from near-IR measurements of polarized scanning atmospheric corrector

Science.gov (United States)

Qie, Lili; Ning, Yuanming; Zhang, Yang; Chen, Xingfeng; Ma, Yan; Li, Zhengqiang; Cui, Wenyu

2018-02-01

Water vapor and aerosol are two key atmospheric factors effecting the remote sensing image quality. As water vapor is responsible for most of the solar radiation absorption occurring in the cloudless atmosphere, accurate measurement of water content is important to not only atmospheric correction of remote sensing images, but also many other applications such as the study of energy balance and global climate change, land surface temperature retrieval in thermal remote sensing. A multi-spectral, single-angular, polarized radiometer called Polarized Scanning Atmospheric Corrector (PSAC) were developed in China, which are designed to mount on the same satellite platform with the principle payload and provide essential parameters for principle payload image atmospheric correction. PSAC detect water vapor content via measuring atmosphere reflectance at water vapor absorbing channels (i.e. 0.91 μm) and nearby atmospheric window channel (i.e. 0.865μm). A near-IR channel ratio method was implemented to retrieve column water vapor (CWV) amount from PSAC measurements. Field experiments were performed at Yantai, in Shandong province of China, PSAC aircraft observations were acquired. The comparison between PSAC retrievals and ground-based Sun-sky radiometer measurements of CWV during the experimental flights illustrates that this method retrieves CWV with relative deviations ranging from 4% 13%. This method retrieve CWV more accurate over land than over ocean, as the water reflectance is low.

Poliomyelitis in MuLV-infected ICR-SCID mice after injection of basement membrane matrix contaminated with lactate dehydrogenase-elevating virus.

Science.gov (United States)

Carlson Scholz, Jodi A; Garg, Rohit; Compton, Susan R; Allore, Heather G; Zeiss, Caroline J; Uchio, Edward M

2011-10-01

The arterivirus lactate dehydrogenase-elevating virus (LDV) causes life-long viremia in mice. Although LDV infection generally does not cause disease, infected mice that are homozygous for the Fv1(n) allele are prone to develop poliomyelitis when immunosuppressed, a condition known as age-dependent poliomyelitis. The development of age-dependent poliomyelitis requires coinfection with endogenous murine leukemia virus. Even though LDV is a common contaminant of transplantable tumors, clinical signs of poliomyelitis after inadvertent exposure to LDV have not been described in recent literature. In addition, LDV-induced poliomyelitis has not been reported in SCID or ICR mice. Here we describe the occurrence of poliomyelitis in ICR-SCID mice resulting from injection of LDV-contaminated basement membrane matrix. After exposure to LDV, a subset of mice presented with clinical signs including paresis, which was associated with atrophy of the hindlimb musculature, and tachypnea; in addition, some mice died suddenly with or without premonitory signs. Mice presenting within the first 6 mo after infection had regions of spongiosis, neuronal necrosis and astrocytosis of the ventral spinal cord, and less commonly, brainstem. Axonal degeneration of ventral roots prevailed in more chronically infected mice. LDV was identified by RT-PCR in 12 of 15 mice with typical neuropathology; positive antiLDV immunolabeling was identified in all PCR-positive animals (n = 7) tested. Three of 8 mice with neuropathology but no clinical signs were LDV negative by RT-PCR. RT-PCR yielded murine leukemia virus in spinal cords of all mice tested, regardless of clinical presentation or neuropathology.

Frequency-scanning interferometry using a time-varying Kalman filter for dynamic tracking measurements.

Science.gov (United States)

Jia, Xingyu; Liu, Zhigang; Tao, Long; Deng, Zhongwen

2017-10-16

Frequency scanning interferometry (FSI) with a single external cavity diode laser (ECDL) and time-invariant Kalman filtering is an effective technique for measuring the distance of a dynamic target. However, due to the hysteresis of the piezoelectric ceramic transducer (PZT) actuator in the ECDL, the optical frequency sweeps of the ECDL exhibit different behaviors, depending on whether the frequency is increasing or decreasing. Consequently, the model parameters of Kalman filter appear time varying in each iteration, which produces state estimation errors with time-invariant filtering. To address this, in this paper, a time-varying Kalman filter is proposed to model the instantaneous movement of a target relative to the different optical frequency tuning durations of the ECDL. The combination of the FSI method with the time-varying Kalman filter was theoretically analyzed, and the simulation and experimental results show the proposed method greatly improves the performance of dynamic FSI measurements.

Scanning Quantum Cryogenic Atom Microscope

Science.gov (United States)

Yang, Fan; Kollár, Alicia J.; Taylor, Stephen F.; Turner, Richard W.; Lev, Benjamin L.

2017-03-01

Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed-matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented dc-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (approximately 2 μ m ) or 6 nT /√{Hz } per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly 100 points with an effective field sensitivity of 600 pT /√{Hz } for each point during the same time as a point-by-point scanner measures these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly 2 orders of magnitude improvement in magnetic flux sensitivity (down to 10-6 Φ0/√{Hz } ) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns in a system where samples may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge-transport images at temperatures from room temperature to 4 K in unconventional superconductors and topologically nontrivial materials.

Surface Laser Scanning Measurements for the n_TOF spallation target

CERN Document Server

Vlachoudis, V; Cennini, P; Lebbos, E; Lettry, J

2010-01-01

The n_TOF spallation target is made of pure lead immersed into cooling water. The target was operating normally from 2001 until august 2004, when an increased transfer of radioactive products from the spallation target to the cooling circuit has been observed. The target was considered damaged by the safety commission (SC/RP), and an investigation campaign started to verify the actual status of the target. According to FLUKA and Ansys calculations the target was working in the elastoplastic regime of the lead material, therefore a deformation might be expected. The present paper describes a laser photographic method and the results of a possible such deformation. The target had a surface activity of the order of 20 mSv/h, therefore we were forced to perform the measurement from distance. The used method, is based on a linelaser and a high resolution digital camera for retrieving the 3D position of the surface of the lead target. Similar methods are used in the film industry and animation studios for scanning ...

Overview of the low energy accelerator scanning system

International Nuclear Information System (INIS)

Leo Kwee Wah; Lojius Lombigit; Muhamad Zahidee Taat; Abu Bakar Ghazali; Mohd Rizal Ibrahim; Mohd Rizal Chulan Md Chulan; Azaman Ahmad; Abdul Halim Baijan; Rokiah Mohd Sabri

2009-01-01

This paper describes the specification of the low energy accelerator (Baby-EBM; Electron Beam Machine) scanning system. It comprises a discussion of coil inductance measurement, power supply design and the test results. The scanning horn system was completely assembled and tested; it was found that the system is able to scan the beam across the scanning window with a required beam profile. (Author)

Transient measurements with an ultrafast scanning tunneling microscope on semiconductor surfaces

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

1998-01-01

We demonstrate: the use of an ultrafast scanning tunneling microscope on a semiconductor surface. Laser-induced transient signals with 1.8 ps rise time are detected, The investigated sample is a low-temperature grown GaAs layer plated on a sapphire substrate with a thin gold layer that serves as st...... bias contact, For comparison, the measurements are performed with the tip in contact to the sample as well as in tunneling above the surface, In contact and under bias, the transient signals are identified as a transient photocurrent, An additional signal is generated by a transient voltage induced...... by the nonuniform carrier density created by the absorption of the light (photo Dember effect). The transient depends in sign and in shape on the direction of optical excitation. This signal is the dominating transient in tunneling mode. The signals are explained by a capacitive coupling across the tunneling gap...

Assessment of breast tumor size in electrical impedance scanning

International Nuclear Information System (INIS)

Kim, Sungwhan

2012-01-01

Electrical impedance scanning (EIS) is a newly introduced imaging technique for early breast cancer detection. In EIS, we apply a sinusoidal voltage between a hand-held electrode and a scanning probe placed on the breast skin to make current travel through the breast. We measure induced currents (Neumann data) through the scanning probe. In this paper, we investigate the frequency-dependent behavior of the induced complex potential and show how the frequency differential of the current measurement on the scanning probe reflects the contrast in complex conductivity values between surrounding and cancerous tissues. Furthermore, we develop the formula for breast tumor size using the frequency differential of the current measurement and provide its feasibility. (paper)

Scan-free grazing emission XRF measurements in the laboratory using a CCD

International Nuclear Information System (INIS)

Szwedowski, Veronika; Baumann, Jonas; Mantouvalou, Ioanna; Bauer, Leona; Malzer, Wolfgang; Kanngiesser, Birgit

2017-01-01

The rapid development of new classes of nanomaterials calls for easy access methods in order to quantify properties essential for their functionality, e.g., interdiffusion of elements at interfaces, or elemental dopant, or depth profiles. Non-destructive methods, like X-ray fluorescence (XRF), are of special interest, for preserving materials and offering the possibility to incorporate the analysis in a production process. In-depth XRF methods for the characterization of nanomaterials are up until now limited to synchrotron radiation facilities. A novel scan-free grazing emission XRF (GEXRF) setup is presented utilizing conventional and low-cost hardware, acting as a transfer of a synchrotron method into the laboratory. A chromium target X-ray tube with a polycapillary lens is used as X-ray source and a conventional CCD as the 2D energy-dispersive detector. To confirm the feasibility of the described setup a nanometer-layered titanium-aluminium sample is measured. An energy-dispersive spectrum is obtained in single-photon-counting-mode from the CCD measurements and first GEXRF profiles generated. A semi-quantitative evaluation of this setup is implemented by comparing the measured results with simulations, allowing conclusions about the investigated samples' elemental, compositional, and structural layer-by-layer characteristics. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Visualization of Lamb Wave Interaction with a 5 mm Fatigue Crack using 1D Ultra High Frequency Laser Doppler Vibrometry

Science.gov (United States)

2011-09-01

detection of a fatigue crack via 3D LDV measurements, both in aluminum plates. All the referenced LDV/guided wave studies made use of PZT or similar...Figure 1a). (b) (a) (c) Figure 1: (a) Test specimen in MTS fatigue test machine, (b) hole with 5 mm crack, (c) PZT placement with...mm thick aluminum plates with a small (1.59 mm) center hole added to facilitate growth of a fatigue crack. One plate was left undamaged while the

A novel scanning interferometer for two-dimensional plasma density measurements

International Nuclear Information System (INIS)

Howard, J.

1989-01-01

A novel multichannel scanning interferometer designed for tomographically inferring contours of electron density in magnetically confined plasmas is described. The scanning element is a multi-sectored blazed rotating grating. The diffracted beam emerges at a different angle from each sector giving rise to a fan array of discrete beams for each rotation of the grating. Signals from the probing chords are multiplexed in time enabling the use of a single detecting element for the extraction of many channels of line integrated density information. An air turbine driven grating wheel assembly has been fabricated and initial tests performed. The proposed interferometer is to be installed on the H-1 helical axis stellarator currently under construction at the Australian National University. 16 refs., 12 figs

In situ measurements of human articular cartilage stiffness by means of a scanning force microscope

International Nuclear Information System (INIS)

Imer, Raphael; Akiyama, Terunobu; Rooij, Nico F de; Stolz, Martin; Aebi, Ueli; Kilger, Robert; Friederich, Niklaus F; Wirz, Dieter; Daniels, A U; Staufer, Urs

2007-01-01

Osteoarthritis is a painful and disabling progressive joint disease, characterized by degradation of articular cartilage. In order to study this disease at early stages, we have miniaturized and integrated a complete scanning force microscope into a standard arthroscopic device fitting through a standard orthopedic canula. This instrument will allow orthopedic surgeons to measure the mechanical properties of articular cartilage at the nanometer and micrometer scale in-vivo during a standard arthroscopy. An orthopedic surgeon assessed the handling of the instrument. First measurements of the elasticity-modulus of human cartilage were recorded in a cadaver knee non minimal invasive. Second, minimally invasive experiments were performed using arthroscopic instruments. Load-displacement curves were successfully recorded

In situ measurements of human articular cartilage stiffness by means of a scanning force microscope

Energy Technology Data Exchange (ETDEWEB)

Imer, Raphael [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Akiyama, Terunobu [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Rooij, Nico F de [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Stolz, Martin [Maurice E. Mueller Institute, University of Basel, Klingelbergstr. 70, 4056 Basel (Switzerland); Aebi, Ueli [Maurice E. Mueller Institute, University of Basel, Klingelbergstr. 70, 4056 Basel (Switzerland); Kilger, Robert [Clinics for Orthopedic Surgery and Traumatology, Kantonsspital, 4101 Bruderholz (Switzerland); Friederich, Niklaus F [Clinics for Orthopedic Surgery and Traumatology, Kantonsspital, 4101 Bruderholz (Switzerland); Wirz, Dieter [Lab. for Orthopaedic Biomechanics, University of Basel, Klingelbergstr. 50-70, 4056 Basel (Switzerland); Daniels, A U [Lab. for Orthopaedic Biomechanics, University of Basel, Klingelbergstr. 50-70, 4056 Basel (Switzerland); Staufer, Urs [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland)

2007-03-15

Osteoarthritis is a painful and disabling progressive joint disease, characterized by degradation of articular cartilage. In order to study this disease at early stages, we have miniaturized and integrated a complete scanning force microscope into a standard arthroscopic device fitting through a standard orthopedic canula. This instrument will allow orthopedic surgeons to measure the mechanical properties of articular cartilage at the nanometer and micrometer scale in-vivo during a standard arthroscopy. An orthopedic surgeon assessed the handling of the instrument. First measurements of the elasticity-modulus of human cartilage were recorded in a cadaver knee non minimal invasive. Second, minimally invasive experiments were performed using arthroscopic instruments. Load-displacement curves were successfully recorded.

Metrological large range scanning probe microscope

International Nuclear Information System (INIS)

Dai Gaoliang; Pohlenz, Frank; Danzebrink, Hans-Ulrich; Xu Min; Hasche, Klaus; Wilkening, Guenter

2004-01-01

We describe a metrological large range scanning probe microscope (LR-SPM) with an Abbe error free design and direct interferometric position measurement capability, aimed at versatile traceable topographic measurements that require nanometer accuracy. A dual-stage positioning system was designed to achieve both a large measurement range and a high measurement speed. This dual-stage system consists of a commercially available stage, referred to as nanomeasuring machine (NMM), with a motion range of 25 mmx25 mmx5 mm along x, y, and z axes, and a compact z-axis piezoelectric positioning stage (compact z stage) with an extension range of 2 μm. The metrological LR-SPM described here senses the surface using a stationary fixed scanning force microscope (SFM) head working in contact mode. During operation, lateral scanning of the sample is performed solely by the NMM. Whereas the z motion, controlled by the SFM signal, is carried out by a combination of the NMM and the compact z stage. In this case the compact z stage, with its high mechanical resonance frequency (greater than 20 kHz), is responsible for the rapid motion while the NMM simultaneously makes slower movements over a larger motion range. To reduce the Abbe offset to a minimum the SFM tip is located at the intersection of three interferometer measurement beams orientated in x, y, and z directions. To improve real time performance two high-end digital signal processing (DSP) systems are used for NMM positioning and SFM servocontrol. Comprehensive DSP firmware and Windows XP-based software are implemented, providing a flexible and user-friendly interface. The instrument is able to perform large area imaging or profile scanning directly without stitching small scanned images. Several measurements on different samples such as flatness standards, nanostep height standards, roughness standards as well as sharp nanoedge samples and 1D gratings demonstrate the outstanding metrological capabilities of the instrument

Evaluation of the Performance of the LCC Windows for Use in Laser Doppler Velocimetry

National Research Council Canada - National Science Library

Chesnakas, Christopher J

2008-01-01

.... The glass windows were found to show benefits for use with LDV in increased measurement accuracy, increased access to the flowfield, decreased time to obtain measurements, and increased capability...

Bone scanning as a routine examination of patients with mammary carcinoma; a critical consideration. [Preoperative scanning

Energy Technology Data Exchange (ETDEWEB)

Heslinga, J M; Pauwels, E K.J.; Zwaveling, A [Rijksuniversiteit Leiden (Netherlands). Academisch Ziekenhuis

1982-06-05

The usefulness of bone scanning as a routine examination was evaluated in 136 female patients with mammary carcinoma of whom 81 were staged as Columbia A and 55 as Columbia B/C. The preoperative bone scanning was positive in only 4 patients (2.9%). Consequently, bone scanning is no longer performed in the authors clinic for the preoperative detection of skeletal metastases. Bone scanning as a routine examination at 6-month intervals does not appear to be useful for the first 4 years of the follow-up, either. Most of the patients with a positive bone scan displayed other signs of skeletal metastases at the same time, such as ostealgia and a raised serum alkaline phosphatase level. Further increase of the frequency of bone scanning during the follow-up period would increase the costs considerably, almost prohibitively, even apart from the question whether such a measure might indeed significantly influence the patient's prognosis. The authors conclude that bone scanning should only be performed on the basis of the anamnesis, physical and laboratory findings, both prior to operation and during the follow-up period.

Scanning holograms

International Nuclear Information System (INIS)

Natali, S.

1984-01-01

This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

Measurement of local critical currents in TFA-MOD processed coated conductors by use of scanning Hall-probe microscopy

International Nuclear Information System (INIS)

Shiohara, K.; Higashikawa, K.; Kawaguchi, T.; Inoue, M.; Kiss, T.; Yoshizumi, M.; Izumi, T.

2011-01-01

We have investigated 2-dimensional distribution of critical current density. We have measured TFA-MOD processed YBCO coated conductor. We used scanning Hall-probe microscopy. These provided information is useful for fabrication process of coated conductor. We have carried out 2-dimensional (2D) measurement of local critical current in a Trifluoroacetates-Metal Organic Deposition (TFA-MOD) processed YBCO coated conductor using scanning Hall-probe microscopy. Recently, remarkable R and D accomplishments on the fabrication processes of coated conductors have been conducted extensively and reported. The TFA-MOD process has been expected as an attractive process to produce coated conductors with high performance at a low production cost due to a simple process using non-vacuum equipments. On the other hand, enhancement of critical currents and homogenization of the critical current distribution in the coated conductors are definitely very important for practical applications. According to our measurements, we can detect positions and spatial distribution of defects in the conductor. This kind of information will be very helpful for the improvement of the TFA-MOD process and for the design of the conductor intended for practical electric power device applications.

Measurement and Model Validation of Nanofluid Specific Heat Capacity with Differential Scanning Calorimetry

Directory of Open Access Journals (Sweden)

Harry O'Hanley

2012-01-01

Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.

A novel approach to measure elemental concentrations in cation exchange resins using XRF-scanning technique, and its potential in water pollution studies

Science.gov (United States)

Huang, Jyh-Jaan; Lin, Sheng-Chi; Löwemark, Ludvig; Liou, Ya-Hsuan; Chang, Queenie; Chang, Tsun-Kuo; Wei, Kuo-Yen; Croudace, Ian W.

2016-04-01

X-ray fluorescence (XRF) core-scanning is a fast, and convenient technique to assess elemental variations for a wide variety of research topics. However, the XRF scanning counts are often considered a semi-quantitative measurement due to possible absorption or scattering caused by down core variability in physical properties. To overcome this problem and extend the applications of XRF-scanning to water pollution studies, we propose to use cation exchange resin (IR-120) as an "elemental carrier", and to analyze the resins using the Itrax-XRF core scanner. The use of resin minimizes the matrix effects during the measurements, and can be employed in the field in great numbers due to its low price. Therefore, the fast, and non-destructive XRF-scanning technique can provide a quick and economical method to analyze environmental pollution via absorption in the resin. Five standard resin samples were scanned by the Itrax-XRF core scanner at different exposure times (1 s, 5 s, 15 s, 30 s, 100 s) to allow the comparisons of scanning counts with the absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in pollution studies (Ca, Ti, Cr, Ni, Cu, Zn, and Pb) were examined for the different exposure times. The result shows that within the test range (from few ppm to thousands ppm), the correlation coefficients are all higher than 0.97, even at the shortest exposure time (1 s). Therefore, we propose to use this method in the field to monitor for example sewage disposal events. The low price of resin, and fast, multi elements and precise XRF-scanning technique provide a viable, cost- and time-effective approach that allows large sample numbers to be processed. In this way, the properties and sources of wastewater pollution can be traced for the purpose of environmental monitoring and environmental forensics.

Sea surface temperature measurements by the along-track scanning radiometer on the ERS 1 satellite: Early results

Science.gov (United States)

Mutlow, C. T.; ZáVody, A. M.; Barton, I. J.; Llewellyn-Jones, D. T.

1994-11-01

The along-track scanning radiometer (ATSR) was launched in July 1991 on the European Space Agency's first remote sensing satellite, ERS 1. An initial analysis of ATSR data demonstrates that the sea surface temperature (SST) can be measured from space with very high accuracy. Comparison of simultaneous measurements of SST made from ATSR and from a ship-borne radiometer show that they agree to within 0.3°C. To assess data consistency, a complementary analysis of SST data from ATSR was also carried out. The ATSR global SST field was compared on a daily basis with daily SST analysis of the United Kingdom Meteorological Office (UKMO). The ATSR global field is consistently within 1.0°C of the UKMO analysis. Also, to demonstrate the benefits of along-track scanning SST determination, the ATSR SST data were compared with high-quality bulk temperature observations from drifting buoys. The likely causes of the differences between ATSR and the bulk temperature data are briefly discussed. These results provide early confidence in the quantitative benefit of ATSR's two-angle view of the Earth and its high radiometric performance and show a significant advance on the data obtained from other spaceborne sensors. It should be noted that these measurements were made at a time when the atmosphere was severely contaminated with volcanic aerosol particles, which degrade infrared measurements of the Earth's surface made from space.

Microprocessor-controlled scanning densitometer system

International Nuclear Information System (INIS)

Shurtliff, R.W.

1980-04-01

An Automated Scanning Densitometer System has been developed by uniting a microprocessor with a low energy x-ray densitometer system. The microprocessor controls the detector movement, provides self-calibration, compensates raw readings to provide time-linear output, controls both data storage and the host computer interface, and provides measurement output in engineering units for immediate reading. The densitometer, when used in a scanning mode, is a precision reference instrument that provides chordal average density measurements over the cross section of a pipe under steady-state flow conditions. Results have shown an improvement over the original densitometer in reliability and repeatability of the system, an a factor-of-five improvement in accuracy

Macro-Logistics Decision Factors and Information Measures for Scanning Global (Supply Chain) Environments in International Location Choice

DEFF Research Database (Denmark)

Kinra, Aseem

2012-01-01

and strategic forecasting needs in relation to international risks. This may be done within the context of decision support systems that aid in global site location and other supply chain design problems. In contrast to solely utilizing widely-accepted environmental scanning indexes, managers may......value chains and supply chain management. This scope is usually accompanied by uncertainty to organisations, especially for the cross-border value chain with geographically dispersed operations and activities, and poses environmental complexity in the form of risks and costs that organisations need...... that pose constraints to international supply chain flows, and describe international uncertainty for firms. A catalogue of 187 information measures that aid in decisions on each relevant factor is also identified. The findings may be used by managers in different industry contexts for their scanning...

Repeatability and Reproducibility of Retinal Nerve Fiber Layer Parameters Measured by Scanning Laser Polarimetry with Enhanced Corneal Compensation in Normal and Glaucomatous Eyes.

Science.gov (United States)

Ara, Mirian; Ferreras, Antonio; Pajarin, Ana B; Calvo, Pilar; Figus, Michele; Frezzotti, Paolo

2015-01-01

To assess the intrasession repeatability and intersession reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness parameters measured by scanning laser polarimetry (SLP) with enhanced corneal compensation (ECC) in healthy and glaucomatous eyes. One randomly selected eye of 82 healthy individuals and 60 glaucoma subjects was evaluated. Three scans were acquired during the first visit to evaluate intravisit repeatability. A different operator obtained two additional scans within 2 months after the first session to determine intervisit reproducibility. The intraclass correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRT) were calculated for all SLP parameters in both groups. ICCs ranged from 0.920 to 0.982 for intravisit measurements and from 0.910 to 0.978 for intervisit measurements. The temporal-superior-nasal-inferior-temporal (TSNIT) average was the highest (0.967 and 0.946) in normal eyes, while nerve fiber indicator (NFI; 0.982) and inferior average (0.978) yielded the best ICC in glaucomatous eyes for intravisit and intervisit measurements, respectively. All COVs were under 10% in both groups, except NFI. TSNIT average had the lowest COV (2.43%) in either type of measurement. Intervisit TRT ranged from 6.48 to 12.84. The reproducibility of peripapillary RNFL measurements obtained with SLP-ECC was excellent, indicating that SLP-ECC is sufficiently accurate for monitoring glaucoma progression.

Mouse manipulation through single-switch scanning.

Science.gov (United States)

Blackstien-Adler, Susie; Shein, Fraser; Quintal, Janet; Birch, Shae; Weiss, Patrice L Tamar

2004-01-01

Given the current extensive reliance on the graphical user interface, independent access to computer software requires that users be able to manipulate a pointing device of some type (e.g., mouse, trackball) or be able to emulate a mouse by some other means (e.g., scanning). The purpose of the present study was to identify one or more optimal single-switch scanning mouse emulation strategies. Four alternative scanning strategies (continuous Cartesian, discrete Cartesian, rotational, and hybrid quadrant/continuous Cartesian) were selected for testing based on current market availability as well as on theoretical considerations of their potential speed and accuracy. Each strategy was evaluated using a repeated measures study design by means of a test program that permitted mouse emulation via any one of four scanning strategies in a motivating environment; response speed and accuracy could be automatically recorded and considered in view of the motor, cognitive, and perceptual demands of each scanning strategy. Ten individuals whose disabilities required them to operate a computer via single-switch scanning participated in the study. Results indicated that Cartesian scanning was the preferred and most effective scanning strategy. There were no significant differences between results from the Continuous Cartesian and Discrete Cartesian scanning strategies. Rotational scanning was quite slow with respect to the other strategies, although it was equally accurate. Hybrid Quadrant scanning improved access time but at the cost of fewer correct selections. These results demonstrated the importance of testing and comparing alternate single-switch scanning strategies.

Assessing ScanSAR Interferometry for Deformation Studies

Science.gov (United States)

Buckley, S. M.; Gudipati, K.

2007-12-01

There is a trend in civil satellite SAR mission design to implement an imaging strategy that incorporates both stripmap mode and ScanSAR imaging. This represents a compromise between high resolution data collection and a desire for greater spatial coverage and more frequent revisit times. However, mixed mode imaging can greatly reduce the number of stripmap images available for measuring subtle ground deformation. Although ScanSAR-ScanSAR and ScanSAR-stripmap repeat-pass interferometry have been demonstrated, these approaches are infrequently used for single interferogram formation and nonexistent for InSAR time series analysis. For future mission design, e.g., a dedicated US InSAR mission, the effect of various ScanSAR system parameter choices on InSAR time series analysis also remains unexplored. Our objective is to determine the utility of ScanSAR differential interferometry. We will demonstrate the use of ScanSAR interferograms for several previous deformation studies: localized and broad-scale urban land subsidence, tunneling, volcanic surface movements and several examples associated with the seismic cycle. We also investigate the effect of various ScanSAR burst synchronization levels on our ability to detect and make quality measurements of deformation. To avoid the issues associated with Envisat ScanSAR burst alignment and to exploit a decade of InSAR measurements, we simulate ScanSAR data by bursting (throwing away range lines of) ERS-1/2 data. All the burst mode datasets are processed using a Modified SPECAN algorithm. To investigate the effects of burst misalignment, a number of cases with varying degrees of burst overlap are considered. In particular, we look at phase decorrelation as a function of percentage of burst overlap. Coherence clearly reduces as the percentage of overlap decreases and we find a useful threshold of 40-70% burst overlap depending on the study site. In order to get a more generalized understanding for different surface conditions

Accuracy of DXA scanning of the thoracic spine: cadaveric studies comparing BMC, areal BMD and geometric estimates of volumetric BMD against ash weight and CT measures of bone volume.

Science.gov (United States)

Sran, Meena M; Khan, Karim M; Keiver, Kathy; Chew, Jason B; McKay, Heather A; Oxland, Thomas R

2005-12-01

Biomechanical studies of the thoracic spine often scan cadaveric segments by dual energy X-ray absorptiometry (DXA) to obtain measures of bone mass. Only one study has reported the accuracy of lateral scans of thoracic vertebral bodies. The accuracy of DXA scans of thoracic spine segments and of anterior-posterior (AP) thoracic scans has not been investigated. We have examined the accuracy of AP and lateral thoracic DXA scans by comparison with ash weight, the gold-standard for measuring bone mineral content (BMC). We have also compared three methods of estimating volumetric bone mineral density (vBMD) with a novel standard-ash weight (g)/bone volume (cm3) as measured by computed tomography (CT). Twelve T5-T8 spine segments were scanned with DXA (AP and lateral) and CT. The T6 vertebrae were excised, the posterior elements removed and then the vertebral bodies were ashed in a muffle furnace. We proposed a new method of estimating vBMD and compared it with two previously published methods. BMC values from lateral DXA scans displayed the strongest correlation with ash weight (r=0.99) and were on average 12.8% higher (pBMC (AP or lateral) was more strongly correlated with ash weight than areal bone mineral density (aBMD; AP: r=0.54, or lateral: r=0.71) or estimated vBMD. Estimates of vBMD with either of the three methods were strongly and similarly correlated with volumetric BMD calculated by dividing ash weight by CT-derived volume. These data suggest that readily available DXA scanning is an appropriate surrogate measure for thoracic spine bone mineral and that the lateral scan might be the scan method of choice.

In-situ measurement of bending strength of TiC whiskers in the scanning electron microscope

Energy Technology Data Exchange (ETDEWEB)

Seino, Yutaka; Shin, Shoichiro; Nagai, Satoshi [National Research Lab. of Metrology, Tsukuba, Ibaraki (Japan)

1995-10-01

The three-point bending strength of TiC whiskers was measured in a scanning electron microscope. The whisker samples have {approximately} 50 {micro}m length and 2 {approximately} 4 {micro}m diameter and are commercially available as reinforcements. For composite materials. The distribution of the bending strengths of the whiskers showed a double peak around 5.2GPa and 30.4GPa, respectively. The difference in these values is attributed to differences in the cleavage strength of two crystal planes depending on whisker growth direction.

Circular mode: a new scanning probe microscopy method for investigating surface properties at constant and continuous scanning velocities.

Science.gov (United States)

Nasrallah, Hussein; Mazeran, Pierre-Emmanuel; Noël, Olivier

2011-11-01

In this paper, we introduce a novel scanning probe microscopy mode, called the circular mode, which offers expanded capabilities for surface investigations especially for measuring physical properties that require high scanning velocities and/or continuous displacement with no rest periods. To achieve these specific conditions, we have implemented a circular horizontal displacement of the probe relative to the sample plane. Thus the relative probe displacement follows a circular path rather than the conventional back and forth linear one. The circular mode offers advantages such as high and constant scanning velocities, the possibility to be combined with other classical operating modes, and a simpler calibration method of the actuators generating the relative displacement. As application examples of this mode, we report its ability to (1) investigate the influence of scanning velocity on adhesion forces, (2) measure easily and instantly the friction coefficient, and (3) generate wear tracks very rapidly for tribological investigations. © 2011 American Institute of Physics

Cryogenic flow rate measurement with a laser Doppler velocimetry standard

Science.gov (United States)

Maury, R.; Strzelecki, A.; Auclercq, C.; Lehot, Y.; Loubat, S.; Chevalier, J.; Ben Rayana, F.

2018-03-01

A very promising alternative to the state-of-the-art static volume measurements for liquefied natural gas (LNG) custody transfer processes is the dynamic principle of flow metering. As the Designated Institute (DI) of the LNE (‘Laboratoire National de métrologie et d’Essais’, being the French National Metrology Institute) for high-pressure gas flow metering, Cesame-Exadebit is involved in various research and development programs. Within the framework of the first (2010-2013) and second (2014-2017) EURAMET Joint Research Project (JRP), named ‘Metrological support for LNG custody transfer and transport fuel applications’, Cesame-Exadebit explored a novel cryogenic flow metering technology using laser Doppler velocimetry (LDV) as an alternative to ultrasonic and Coriolis flow metering. Cesame-Exadebit is trying to develop this technique as a primary standard for cryogenic flow meters. Currently, cryogenic flow meters are calibrated at ambient temperatures with water. Results are then extrapolated to be in the Reynolds number range of real applications. The LDV standard offers a unique capability to perform online calibration of cryogenic flow meters in real conditions (temperature, pressure, piping and real flow disturbances). The primary reference has been tested on an industrial process in a LNG terminal during truck refuelling. The reference can calibrate Coriolis flow meters being used daily with all the real environmental constraints, and its utilisation is transparent for LNG terminal operators. The standard is traceable to Standard International units and the combined extended uncertainties have been determined and estimated to be lower than 0.6% (an ongoing improvement to reducing the correlation function uncertainty, which has a major impact in the uncertainty estimation).

Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongkyu, E-mail: akein@gist.ac.kr; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan, E-mail: khpark@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, South Korea, 500-712 (Korea, Republic of)

2016-06-28

An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

Ledipasvir/sofosbuvir for treatment of hepatitis C virus in sofosbuvir-experienced, NS5A treatment-naïve patients: Findings from two randomized trials.

Science.gov (United States)

Tam, Edward; Luetkemeyer, Anne F; Mantry, Parvez S; Satapathy, Sanjaya K; Ghali, Peter; Kang, Minhee; Haubrich, Richard; Shen, Xianlin; Ni, Liyun; Camus, Gregory; Copans, Amanda; Rossaro, Lorenzo; Guyer, Bill; Brown, Robert S

2018-06-01

We report data from two similarly designed studies that evaluated the efficacy, safety, and optimal duration of ledipasvir/sofosbuvir (LDV/SOF) ± ribavirin (RBV) for retreatment of chronic hepatitis C virus (HCV) in individuals who failed to achieve sustained virological response (SVR) with prior SOF-based, non-NS5A inhibitor-containing regimens. The RESCUE study enrolled HCV mono-infected adults with genotype (GT) 1 or 4. Non-cirrhotic participants were randomized to 12 weeks of LDV/SOF or LDV/SOF + RBV. Compensated cirrhotic participants were randomized to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). The AIDS Clinical Trials Group A5348 study randomized genotype 1 adults with HCV/HIV co-infection to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). Both studies used SVR at 12 weeks post-treatment (SVR12) as the primary endpoint. In the RESCUE study, 82 participants were randomized and treated, and all completed treatment. Overall, SVR12 was 88% (72/82); 81-100% in non-cirrhotic participants treated with LDV/SOF or LDV/SOF + RBV for 12 weeks and 80-92% in cirrhotic participants treated with LDV/SOF + RBV for 12 weeks or LDV/SOF for 24 weeks. Adverse events (AEs), mostly mild-to-moderate in severity, were experienced by 78% of participants, with headache and fatigue most frequently reported. One serious AE, not related to treatment, was observed. No premature discontinuations of study drug, or deaths occurred. In the A5348 study, seven participants were randomized (cirrhotic n = 1; GT1a n = 5) and all attained SVR12, with no serious AEs or premature discontinuations. In this SOF-experienced, NS5A inhibitor-naïve population, which included participants with cirrhosis or HCV/HIV co-infection, high SVR12 rates were achieved. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Acquirement and enhancement of remote speech signals

Science.gov (United States)

Lü, Tao; Guo, Jin; Zhang, He-yong; Yan, Chun-hui; Wang, Can-jin

2017-07-01

To address the challenges of non-cooperative and remote acoustic detection, an all-fiber laser Doppler vibrometer (LDV) is established. The all-fiber LDV system can offer the advantages of smaller size, lightweight design and robust structure, hence it is a better fit for remote speech detection. In order to improve the performance and the efficiency of LDV for long-range hearing, the speech enhancement technology based on optimally modified log-spectral amplitude (OM-LSA) algorithm is used. The experimental results show that the comprehensible speech signals within the range of 150 m can be obtained by the proposed LDV. The signal-to-noise ratio ( SNR) and mean opinion score ( MOS) of the LDV speech signal can be increased by 100% and 27%, respectively, by using the speech enhancement technology. This all-fiber LDV, which combines the speech enhancement technology, can meet the practical demand in engineering.

Measurement of stray radiation within a scanning proton therapy facility: EURADOS WG9 intercomparison exercise of active dosimetry systems

Czech Academy of Sciences Publication Activity Database

Farah, J.; Mares, V.; Romero-Exposito, M.; Trinkl, S.; Domingo, C.; Dufek, V.; Klodowska, M.; Kubančák, Ján; Knezevic, Z.; Ploc, Ondřej

2015-01-01

Roč. 42, č. 5 (2015), s. 2572-2584 ISSN 0094-2405 Institutional support: RVO:61389005 Keywords : scanning proton therapy * measurement of stray neutrons * spectrometry * ambient dose eyuivalent * intercomparison Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.496, year: 2015

Four-probe measurements with a three-probe scanning tunneling microscope

International Nuclear Information System (INIS)

Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A.

2014-01-01

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe

Four-probe measurements with a three-probe scanning tunneling microscope

Energy Technology Data Exchange (ETDEWEB)

Salomons, Mark [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A., E-mail: rwolkow@ualberta.ca [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

2014-04-15

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

Four-probe measurements with a three-probe scanning tunneling microscope.

Science.gov (United States)

Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

2014-04-01

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

In Vitro Antiviral Activity and Resistance Profile Characterization of the Hepatitis C Virus NS5A Inhibitor Ledipasvir.

Science.gov (United States)

Cheng, Guofeng; Tian, Yang; Doehle, Brian; Peng, Betty; Corsa, Amoreena; Lee, Yu-Jen; Gong, Ruoyu; Yu, Mei; Han, Bin; Xu, Simin; Dvory-Sobol, Hadas; Perron, Michel; Xu, Yili; Mo, Hongmei; Pagratis, Nikos; Link, John O; Delaney, William

2016-01-11

Ledipasvir (LDV; GS-5885), a component of Harvoni (a fixed-dose combination of LDV with sofosbuvir [SOF]), is approved to treat chronic hepatitis C virus (HCV) infection. Here, we report key preclinical antiviral properties of LDV, including in vitro potency, in vitro resistance profile, and activity in combination with other anti-HCV agents. LDV has picomolar antiviral activity against genotype 1a and genotype 1b replicons with 50% effective concentration (EC50) values of 0.031 nM and 0.004 nM, respectively. LDV is also active against HCV genotypes 4a, 4d, 5a, and 6a with EC50 values of 0.11 to 1.1 nM. LDV has relatively less in vitro antiviral activity against genotypes 2a, 2b, 3a, and 6e, with EC50 values of 16 to 530 nM. In vitro resistance selection with LDV identified the single Y93H and Q30E resistance-associated variants (RAVs) in the NS5A gene; these RAVs were also observed in patients after a 3-day monotherapy treatment. In vitro antiviral combination studies indicate that LDV has additive to moderately synergistic antiviral activity when combined with other classes of HCV direct-acting antiviral (DAA) agents, including NS3/4A protease inhibitors and the nucleotide NS5B polymerase inhibitor SOF. Furthermore, LDV is active against known NS3 protease and NS5B polymerase inhibitor RAVs with EC50 values equivalent to those for the wild type. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Compact scanning tunneling microscope for spin polarization measurements.

Science.gov (United States)

Kim, Seong Heon; de Lozanne, Alex

2012-10-01

We present a design for a scanning tunneling microscope that operates in ultrahigh vacuum down to liquid helium temperatures in magnetic fields up to 8 T. The main design philosophy is to keep everything compact in order to minimize the consumption of cryogens for initial cool-down and for extended operation. In order to achieve this, new ideas were implemented in the design of the microscope body, dewars, vacuum chamber, manipulators, support frame, and vibration isolation. After a brief description of these designs, the results of initial tests are presented.

Safety, efficacy, and predictability of laser in situ keratomileusis to correct myopia or myopic astigmatism with a 750 Hz scanning-spot laser system.

Science.gov (United States)

Tomita, Minoru; Watabe, Miyuki; Yukawa, Satoshi; Nakamura, Nobuo; Nakamura, Tadayuki; Magnago, Thomas

2014-02-01

To evaluate the clinical outcomes of laser in situ keratomileusis (LASIK) to correct myopia or myopic astigmatism using the Amaris 750S 750 Hz excimer laser. Private LASIK center, Tokyo, Japan. Case series. Patients with myopia or myopic astigmatism (spherical equivalent -0.50 to -11.63 diopters [D]), a corrected distance visual acuity (CDVA) of 20/20 or better, and an estimated residual bed thickness of 300 μm or more had LASIK using the aspheric aberration-free ablation profile of the 750 Hz scanning-spot laser and the Femto LDV Crystal Line femtosecond laser for flap creation. Study parameters included uncorrected distance visual acuity (UDVA), CDVA, manifest refraction, astigmatism, and higher-order aberrations (HOAs). The study included 1280 eyes (685 patients). At 3 months, 96.6% of eyes had a UDVA of 20/20 or better and 99.1% had 20/32 or better; 94.1% of eyes were within ± 0.50 D of the intended correction and 98.9% were within ± 1.00 D; 89.7% of eyes had no residual cylinder and 96.0% had a postoperative astigmatism of less than 0.50 D. All eyes had a postoperative CDVA of 20/20 or better. The HOAs increased postoperatively (PLaser in situ keratomileusis with the 750 Hz scanning-spot laser was safe, effective, and predictable. No specific clinical side effects that might be associated with a high repetition rate occurred. Mr. Magnago is an employee of Schwind eye-tech-solutions GmbH. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Geometrical modelling of scanning probe microscopes and characterization of errors

International Nuclear Information System (INIS)

Marinello, F; Savio, E; Bariani, P; Carmignato, S

2009-01-01

Scanning probe microscopes (SPMs) allow quantitative evaluation of surface topography with ultra-high resolution, as a result of accurate actuation combined with the sharpness of tips. SPMs measure sequentially, by scanning surfaces in a raster fashion: topography maps commonly consist of data sets ideally reported in an orthonormal rectilinear Cartesian coordinate system. However, due to scanning errors and measurement distortions, the measurement process is far from the ideal Cartesian condition. The paper addresses geometrical modelling of the scanning system dynamics, presenting a mathematical model which describes the surface metric x-, y- and z- coordinates as a function of the measured x'-, y'- and z'-coordinates respectively. The complete mathematical model provides a relevant contribution to characterization and calibration, and ultimately to traceability, of SPMs, when applied for quantitative characterization

Thyroid Scan and Uptake

Medline Plus

Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

SU-F-T-184: 3D Range-Modulator for Scanned Particle Therapy: Development, Monte Carlo Simulations and Measurements

Energy Technology Data Exchange (ETDEWEB)

Simeonov, Y; Penchev, P; Ringbaek, T Printz [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); Brons, S [Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); Weber, U [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Zink, K [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); University Hospital Giessen-Marburg, Marburg (Germany)

2016-06-15

Purpose: Active raster scanning in particle therapy results in highly conformal dose distributions. Treatment time, however, is relatively high due to the large number of different iso-energy layers used. By using only one energy and the so called 3D range-modulator irradiation times of a few seconds only can be achieved, thus making delivery of homogeneous dose to moving targets (e.g. lung cancer) more reliable. Methods: A 3D range-modulator consisting of many pins with base area of 2.25 mm2 and different lengths was developed and manufactured with rapid prototyping technique. The form of the 3D range-modulator was optimised for a spherical target volume with 5 cm diameter placed at 25 cm in a water phantom. Monte Carlo simulations using the FLUKA package were carried out to evaluate the modulating effect of the 3D range-modulator and simulate the resulting dose distribution. The fine and complicated contour form of the 3D range-modulator was taken into account by a specially programmed user routine. Additionally FLUKA was extended with the capability of intensity modulated scanning. To verify the simulation results dose measurements were carried out at the Heidelberg Ion Therapy Center (HIT) with a 400.41 MeV 12C beam. Results: The high resolution measurements show that the 3D range-modulator is capable of producing homogeneous 3D conformal dose distributions, simultaneously reducing significantly irradiation time. Measured dose is in very good agreement with the previously conducted FLUKA simulations, where slight differences were traced back to minor manufacturing deviations from the perfect optimised form. Conclusion: Combined with the advantages of very short treatment time the 3D range-modulator could be an alternative to treat small to medium sized tumours (e.g. lung metastasis) with the same conformity as full raster-scanning treatment. Further simulations and measurements of more complex cases will be conducted to investigate the full potential of the 3D

Scanning confocal slit photon counter measurements of post-PRK haze in two-year study

Science.gov (United States)

Taboada, John; Gaines, David; Perez, Mary A.; Waller, Steve G.; Ivan, Douglas J.; Baldwin, J. Bruce; LoRusso, Frank; Tutt, Ronald C.; Thompson, B.; Perez, Jose; Tredici, Thomas; Johnson, Dan A.

2001-06-01

In our study, a group of 80 United States Air Force, non- flying personnel will undergo photorefractive corneal surgery for moderate levels of myopia (< 6 diopters) and 20 will serve as controls. As of this report, approximately 56 have had the treatment. Of these, only about 59% of the treated eyes showed even a trace (.5) level of clinically assessed haze at any time. We report on the use of a recently developed instrument designed for the objective measurement of these low levels of haze in treated corneas. The sensitivity of the instrument is derived from the use of a scanning confocal slit photon counter. The use of a physical standard for calibration secures accuracy and reproducibility over an extensive period of time. Our haze measurements in this study revealed a very low level increase from baseline values for these patients. The typical increase over baseline was of the same magnitude as the variability in the observations, although the inherent variability in the measurements was approximately 0.25 times the value of the patient's haze variability.

Influence of material surface on the scanning error of a powder-free 3D measuring system

OpenAIRE

Kurz, Michael; Attin, Thomas; Mehl, Albert

2015-01-01

OBJECTIVES This study aims to evaluate the accuracy of a powder-free three-dimensional (3D) measuring system (CEREC Omnicam, Sirona), when scanning the surface of a material at different angles. Additionally, the influence of water was investigated. MATERIALS AND METHODS Nine different materials were combined with human tooth surface (enamel) to create n = 27 specimens. These materials were: Controls (InCoris TZI and Cerec Guide Bloc), ceramics (Vitablocs® Mark II and IPS Empress CAD), met...

Simultaneous scanning tunneling microscopy and synchrotron X-ray measurements in a gas environment.

Science.gov (United States)

Mom, Rik V; Onderwaater, Willem G; Rost, Marcel J; Jankowski, Maciej; Wenzel, Sabine; Jacobse, Leon; Alkemade, Paul F A; Vandalon, Vincent; van Spronsen, Matthijs A; van Weeren, Matthijs; Crama, Bert; van der Tuijn, Peter; Felici, Roberto; Kessels, Wilhelmus M M; Carlà, Francesco; Frenken, Joost W M; Groot, Irene M N

2017-11-01

A combined X-ray and scanning tunneling microscopy (STM) instrument is presented that enables the local detection of X-ray absorption on surfaces in a gas environment. To suppress the collection of ion currents generated in the gas phase, coaxially shielded STM tips were used. The conductive outer shield of the coaxial tips can be biased to deflect ions away from the tip core. When tunneling, the X-ray-induced current is separated from the regular, 'topographic' tunneling current using a novel high-speed separation scheme. We demonstrate the capabilities of the instrument by measuring the local X-ray-induced current on Au(1 1 1) in 800 mbar Ar. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationships between road safety, safety measures and external factors : a scan of the literature in view of model development and topics for further research.

NARCIS (Netherlands)

Churchill, T. & Norden, Y. van

2010-01-01

The purpose of this literature scan is to examine where literature on the effect of external factors and road safety measures on road safety exists and where it is lacking. This scan will help us to decide which factors to include in a comprehensive road safety model as SWOV is working on, and at

Power Measurements for Microvision, Inc., Aircrew Integrated Helmet System Scanning Laser Helmet-Mounted Display

National Research Council Canada - National Science Library

Rash, Clarence

2002-01-01

...) technology based on scanning lasers. Under this program, Microvision, Inc., Bothell, Washington, has developed a scanning laser HMD prototype for use with the Aircrew Integrated Helmet System (AIHS...

Near-field scanning optical microscopy cross-sectional measurements of crystalline GaAs solar cells

International Nuclear Information System (INIS)

Herndon, M. K.; Bradford, W. C.; Collins, R. T.; Hawkins, B. E.; Kuech, T. F.; Friedman, D. J.; Kurtz, S. R.

2000-01-01

Near-field scanning optical microscopy (NSOM) was used to study cleaved edges of GaAs solar cell devices. Using visible light for excitation, the NSOM acquired spatially resolved traces of the photocurrent response across the various layers in the device. For excitation energies well above the band gap, carrier recombination at the cleaved surface had a strong influence on the photocurrent signal. Decreasing the excitation energy, which increased the optical penetration depth, allowed the effects of surface recombination to be separated from collection by the pn junction. Using this approach, the NSOM measurements directly observed the effects of a buried minority carrier reflector/passivation layer. (c) 2000 American Institute of Physics

SU-E-T-594: Preliminary Active Scanning Results of KHIMA

International Nuclear Information System (INIS)

Kim, C; Yang, T; Chang, S; Kim, H; Lee, H; Kim, J; Jang, H; Han, G; Park, D; Hwang, W; Kim, G

2014-01-01

Purpose: To verify the design criteria on heavy ion beam irradiation, developing a proto type active scanning system was purposed. The active scanning system consists of scanning magnet, power supplies, beam monitors, energy modulation system, and irradiation control system. Methods: Each components of the active scanning system was designed for carbon beam first. For the fast ramping a laminated yoke was purposed. To measure incoming dose and profile, a plate and strip type of ion chambers were designed. Also, ridge filter and range shifter was manufactured. And, the scanning system was modified to adopt 45 MeV of proton beam because of the absence of carbon ion beam in Korea. The system was installed in a beam line at MC-50, KIRAMS. Also, the irradiation control system and planning software was provided. Results: The scanning experiment was performed by drawing KHIMA logo on GaF film. The logo was scanned by 237 scanning points through time normalized intensity modulation. Also, a grid points scanning was performed to measure the scanning resolution and intensity resolution. Conclusion: A prototype active scanning system was successfully designed and manufactured. Also, an initial experiment to print out a drawing on GaF film through the scanning system was completed. More experiments would be required to specify the system performance

PIV Measurements in Weakly Buoyant Gas Jet Flames

Science.gov (United States)

Sunderland, Peter B.; Greenbberg, Paul S.; Urban, David L.; Wernet, Mark P.; Yanis, William

2001-01-01

Despite numerous experimental investigations, the characterization of microgravity laminar jet diffusion flames remains incomplete. Measurements to date have included shapes, temperatures, soot properties, radiative emissions and compositions, but full-field quantitative measurements of velocity are lacking. Since the differences between normal-gravity and microgravity diffusion flames are fundamentally influenced by changes in velocities, it is imperative that the associated velocity fields be measured in microgravity flames. Velocity measurements in nonbuoyant flames will be helpful both in validating numerical models and in interpreting past microgravity combustion experiments. Pointwise velocity techniques are inadequate for full-field velocity measurements in microgravity facilities. In contrast, Particle Image Velocimetry (PIV) can capture the entire flow field in less than 1% of the time required with Laser Doppler Velocimetry (LDV). Although PIV is a mature diagnostic for normal-gravity flames , restrictions on size, power and data storage complicate these measurements in microgravity. Results from the application of PIV to gas jet flames in normal gravity are presented here. Ethane flames burning at 13, 25 and 50 kPa are considered. These results are presented in more detail in Wernet et al. (2000). The PIV system developed for these measurements recently has been adapted for on-rig use in the NASA Glenn 2.2-second drop tower.

Developments in Scanning Hall Probe Microscopy

Science.gov (United States)

Chouinard, Taras; Chu, Ricky; David, Nigel; Broun, David

2009-05-01

Low temperature scanning Hall probe microscopy is a sensitive means of imaging magnetic structures with high spatial resolution and magnetic flux sensitivity approaching that of a Superconducting Quantum Interference Device. We have developed a scanning Hall probe microscope with novel features, including highly reliable coarse positioning, in situ optimization of sensor-sample alignment and capacitive transducers for linear, long range positioning measurement. This has been motivated by the need to reposition accurately above fabricated nanostructures such as small superconducting rings. Details of the design and performance will be presented as well as recent progress towards time-resolved measurements with sub nanosecond resolution.

Measurement of the vortex-core radius by scanning tunneling microscopy

NARCIS (Netherlands)

Hartmann, U.; Golubov, Alexandre Avraamovitch; Drechsler, T.; Kupriyanov, M. Yu; Heiden, C.

1994-01-01

Using a scanning tunneling microscope operated in a spectroscopic mode we imaged flux-line lattices in niobium diselenide at various external magnetic fields. From the evaluation of a large number of tunneling-current profiles taken across the individual vortices we deduced the dependence of the

An environmental sample chamber for reliable scanning transmission x-ray microscopy measurements under water vapor

Energy Technology Data Exchange (ETDEWEB)

Kelly, Stephen T.; Nigge, Pascal; Prakash, Shruti; Gilles, Mary K. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Laskin, Alexander; Wang, Bingbing [William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Tyliszczak, Tolek [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leone, Stephen R. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry and Department of Physics, University of California, Berkeley, California 94720 (United States)

2013-07-15

We have designed, fabricated, and tested a compact gas-phase reactor for performing in situ soft x-ray scanning transmission x-ray microscopy (STXM) measurements. The reactor mounts directly to the existing sample holder used in the majority of STXM instruments around the world and installs with minimal instrument reconfiguration. The reactor accommodates many gas atmospheres, but was designed specifically to address the needs of measurements under water vapor. An on-board sensor measures the relative humidity and temperature inside the reactor, minimizing uncertainties associated with measuring these quantities outside the instrument. The reactor reduces x-ray absorption from the process gas by over 85% compared to analogous experiments with the entire STXM instrument filled with process gas. Reduced absorption by the process gas allows data collection at full instrumental resolution, minimizes radiation dose to the sample, and results in much more stable imaging conditions. The reactor is in use at the STXM instruments at beamlines 11.0.2 and 5.3.2.2 at the Advanced Light Source.

Improving the scanning speed of atomic force microscopy at the scanning range of several tens of micrometers

International Nuclear Information System (INIS)

Wang, Yanyan; Hu, Xiaodong; Xu, Linyan; Hu, Xiaotang

2013-01-01

The atomic force microscope (AFM) is a powerful instrument which can measure the surface of samples at the nanoscale. The resonance of the scanner in xy directions, and the feedback control in the z direction are two major sources of image distortion at high scan speed. In order to improve the scanning speed of the AFM, a low-cost and easy method, which includes sinusoidal scans in the fast scan direction, and an intelligent fuzzy controller in the z direction, is proposed in this paper. The use of a single-frequency driving signal in the fast scan direction allows the scanner to move at a higher speed without exciting its mechanical resonance. The intelligent fuzzy controller automatically selects appropriate PI parameters through the analysis of the tracking errors, thus improving the dynamic tracking performance of the z scanner. The development and functioning of the sinusoidal fast scans and the intelligent fuzzy controller are demonstrated, as well as how this approach significantly achieves faster scans and a higher resolution AFM imaging. -- Highlights: ► The sinusoidal scan and the intelligent controller are used to improve AFM's rate. ► A new method is raised to overcome the nonlinearity caused by the sinusoidal scan. ► A new controller is proposed to improve the performance of the vertical direction.

The along track scanning radiometer for ERS-1 - Scan geometry and data simulation

Science.gov (United States)

Prata, A. J. Fred; Cechet, Robert P.; Barton, Ian J.; Llewellyn-Jones, David T.

1990-01-01

The first European remote-sensing satellite (ERS-1), due to be launched in 1990, will carry the along track scanning radiometer (ATSR), which has been specifically designed to give accurate satellite measurements of sea surface temperature (SST). Details of the novel scanning technique used by the ATSR are given, and data from the NOAA-9 AVHRR instrument are used to simulate raw ATSR imagery. Because of the high precision of the onboard blackbodies, the active cooling of the detectors, 12-b digitization, and dual-angle capability, the ATSR promises to achieve higher-accuracy satellite-derived SSTs than are currently available.

3D wake measurements from a scanning wind lidar in combination with a fast wind field reconstruction model

DEFF Research Database (Denmark)

Mikkelsen, Torben Krogh; Herges, T. G.; Astrup, Poul

2017-01-01

University of Denmark. The purpose of the SpinnerLidar measurements at SWIFT is to measure the response of a V27 turbine wake to varying inflow conditions and turbine operating states. Although our fast scanning SpinnerLidar is able to measure the line-of-sight projected wind speed at up to 400 points per......-Stokes CFD code “Lincom Cyclop-buster model,”3 the corresponding 3D wind vector field (u, v, w) can be reconstructed under constraints for conservation of mass and momentum. The resulting model calculated line-of-sight projections of the 3D wind velocity vectors will become consistent with the line...

Patient exposure during thyroid scan in Khartoum Hospital

International Nuclear Information System (INIS)

Saeed, N. E. B.

2013-03-01

The aim of this study was to measure exposure during thyroid scan by using technetium-9 9m radioactive isotope. This study was conducted on 35 patients under thyroid scan, measured in Alnelein diagnostic center, data collected for the study included, age, sex, height, weight, and the material used in examination and the activity half-life of the material. The mean age was 41.83 years, while the mean body mass index (BMI) was 24.40, and the value of effective dose average 2.65±0.24 mSv. Data collected were analyzed by excel software and statistical analysis program, where the process of analysis category was given such as: age weight of patient, time of scan, the activity and the effective dose, it was found that thyroid scan was more common in female than male patients.(Author)

Scanning transmission ion microscopy mass measurements for quantitative trace element analysis within biological samples and validation using atomic force microscopy thickness measurements

Energy Technology Data Exchange (ETDEWEB)

Deves, Guillaume [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)]. E-mail: deves@cenbg.in2p3.fr; Cohen-Bouhacina, Touria [Centre de Physique Moleculaire Optique et Hertzienne, Universite de Bordeaux 1, 351, cours de la Liberation, F33405 Talence cedex (France); Ortega, Richard [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)

2004-10-08

We used the nuclear microprobe techniques, micro-PIXE (particle-induced X-ray emission), micro-RBS (Rutherford backscattering spectrometry) and scanning transmission ion microscopy (STIM) in order to perform the characterization of trace element content and spatial distribution within biological samples (dehydrated cultured cells, tissues). The normalization of PIXE results was usually expressed in terms of sample dry mass as determined by micro-RBS recorded simultaneously to micro-PIXE. However, the main limit of RBS mass measurement is the sample mass loss occurring during irradiation and which could be up to 30% of the initial sample mass. We present here a new methodology for PIXE normalization and quantitative analysis of trace element within biological samples based on dry mass measurement performed by mean of STIM. The validation of STIM cell mass measurements was obtained in comparison with AFM sample thickness measurements. Results indicated the reliability of STIM mass measurement performed on biological samples and suggested that STIM should be performed for PIXE normalization. Further information deriving from direct confrontation of AFM and STIM analysis could as well be obtained, like in situ measurements of cell specific gravity within cells compartment (nucleolus and cytoplasm)

Three-dimensional image analysis of the skull using variable CT scanning protocols-effect of slice thickness on measurement in the three-dimensional CT images

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ho Gul; Kim, Kee Deog; Park, Hyok; Kim, Dong Ook; Jeong, Hai Jo; Kim, Hee Joung; Yoo, Sun Kook; Kim, Yong Oock; Park, Chang Seo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

2004-07-15

To evaluate the quantitative accuracy of three-dimensional (3D) images by mean of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0 (Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons' two-sample test. 11 line items in Conventional 3 mm, 8 in Helical 3 mm, 11 in Conventional 5 mm, 10 in Helical 5 mm, 5 in Conventional 7 mm and 9 in Helical 7 mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2 mm in 19 line items of Conventional 3 mm. 20 of Helical 3 mm, 15 of Conventional 5 mm, 18 of Helical 5 mm, 11 of Conventional 7 mm and 16 of Helical 7 mm. Considering image quality and patient's exposure time, scanning protocol of Helical 5 mm is recommended for 3D image analysis of the skull in CT.

Theory of a Quantum Scanning Microscope for Cold Atoms.

Science.gov (United States)

Yang, D; Laflamme, C; Vasilyev, D V; Baranov, M A; Zoller, P

2018-03-30

We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.

Measurement Variability of Vertical Scanning Interferometry Tool Used for Orbiter Window Defect Assessment

Science.gov (United States)

Padula, Santo, II

2009-01-01

The ability to sufficiently measure orbiter window defects to allow for window recertification has been an ongoing challenge for the orbiter vehicle program. The recent Columbia accident has forced even tighter constraints on the criteria that must be met in order to recertify windows for flight. As a result, new techniques are being investigated to improve the reliability, accuracy and resolution of the defect detection process. The methodology devised in this work, which is based on the utilization of a vertical scanning interferometric (VSI) tool, shows great promise for meeting the ever increasing requirements for defect detection. This methodology has the potential of a 10-100 fold greater resolution of the true defect depth than can be obtained from the currently employed micrometer based methodology. An added benefit is that it also produces a digital elevation map of the defect, thereby providing information about the defect morphology which can be utilized to ascertain the type of debris that induced the damage. However, in order to successfully implement such a tool, a greater understanding of the resolution capability and measurement repeatability must be obtained. This work focused on assessing the variability of the VSI-based measurement methodology and revealed that the VSI measurement tool was more repeatable and more precise than the current micrometer based approach, even in situations where operator variation could affect the measurement. The analysis also showed that the VSI technique was relatively insensitive to the hardware and software settings employed, making the technique extremely robust and desirable

Harmonisation of nanoparticle concentration measurements using GRIMM and TSI scanning mobility particle sizers

International Nuclear Information System (INIS)

Joshi, Manish; Sapra, B. K.; Khan, Arshad; Tripathi, S. N.; Shamjad, P. M.; Gupta, Tarun; Mayya, Y. S.

2012-01-01

Regional studies focusing on the role of atmospheric nanoparticles in climate change have gained impetus in the last decade. Several multi-institutional studies involving measurement of nanoparticles with several kinds of instruments are on the rise. It is important to harmonize these measurements as the instruments may work on different techniques or principles and are developed by different manufacturers. Scanning mobility particle sizers (SMPS) are often used to measure size distribution of nanoparticles in the airborne phase. Two such commercially available instruments namely, GRIMM and TSI-SMPS have been compared for ambient and laboratory generated conditions. A stand-alone condensation particle counter (CPC) of TSI make was used as a reference for particle concentration measurements. The consistency of the results in terms of mean size and geometric standard deviation was seen to be excellent for both the SMPSs, with GRIMM always showing slightly (approximately 10 %) lower mean size. The integrated number concentration from GRIMM-SMPS was seen to be closer to stand-alone reference CPC compared to TSI-SMPS, for an ambient overnight comparison. However, a concentration-dependent response, i.e. the variations between the two instruments increasing with the concentration, was observed and possible reasons for this have been suggested. A separate experiment was performed for studying the modifying effect of diffusion dryer and sheath air dryer on the measured aerosol size spectra. A significant hygroscopic growth was noted when diffusion dryer was attached to one of the SMPS. The introduction of sheath air dryer in GRIMM-SMPS produced a significant shift towards lower mean size. These results have been compared and discussed with the recent inter-comparison results to strengthen and harmonize the measurement protocols.

Harmonisation of nanoparticle concentration measurements using GRIMM and TSI scanning mobility particle sizers

Science.gov (United States)

Joshi, Manish; Sapra, B. K.; Khan, Arshad; Tripathi, S. N.; Shamjad, P. M.; Gupta, Tarun; Mayya, Y. S.

2012-12-01

Regional studies focusing on the role of atmospheric nanoparticles in climate change have gained impetus in the last decade. Several multi-institutional studies involving measurement of nanoparticles with several kinds of instruments are on the rise. It is important to harmonize these measurements as the instruments may work on different techniques or principles and are developed by different manufacturers. Scanning mobility particle sizers (SMPS) are often used to measure size distribution of nanoparticles in the airborne phase. Two such commercially available instruments namely, GRIMM and TSI-SMPS have been compared for ambient and laboratory generated conditions. A stand-alone condensation particle counter (CPC) of TSI make was used as a reference for particle concentration measurements. The consistency of the results in terms of mean size and geometric standard deviation was seen to be excellent for both the SMPSs, with GRIMM always showing slightly (approximately 10 %) lower mean size. The integrated number concentration from GRIMM-SMPS was seen to be closer to stand-alone reference CPC compared to TSI-SMPS, for an ambient overnight comparison. However, a concentration-dependent response, i.e. the variations between the two instruments increasing with the concentration, was observed and possible reasons for this have been suggested. A separate experiment was performed for studying the modifying effect of diffusion dryer and sheath air dryer on the measured aerosol size spectra. A significant hygroscopic growth was noted when diffusion dryer was attached to one of the SMPS. The introduction of sheath air dryer in GRIMM-SMPS produced a significant shift towards lower mean size. These results have been compared and discussed with the recent inter-comparison results to strengthen and harmonize the measurement protocols.

Study of Anthropometric Measurements of the Anterior Ethmoidal Artery using Three-dimensional Scanning on 300 Patients

Science.gov (United States)

Bortoli, Vinicius Tomadon; Martins, Rafael Ferri; Negri, Krystal Calmeto

2017-01-01

Introduction The anterior ethmoidal artery (AEA) is one of the main arteries that supply both the nasal mucosa and the ethmoid sinuses. The AEA shows variability regarding its distance from adjacent structures. Several studies have developed techniques to identify the AEA. Objective This study aimed to compare the measurements from the AEA to the ethmoid bulla and to the frontal beak by using computed tomography of the face, while identifying their intraindividual and interindividual variations. Methods We analyzed 300 CT scans of the face performed at the CT scan Center at Hospital. The average age of subjects was 36 ± 15.1 years (range 4–84). Results We found that the average distance from the AEA to the ethmoid bulla was 17.2 ± 1.8 mm and the distance from the AEA to the frontal beak was 15.1 ± 2.2 mm. Regarding the average distance from the AEA to the frontal beak (AEA-frontal beak), there was a difference between the right and left sides, with the former being 0.4 mm higher on average than the latter. Among the age groups, there was a significant difference of distances between the AEA and the ethmoid bulla (AEA-ethmoid bulla), which were shorter in the ≤ 12 years group. There was a positive and significant correlation between both measurements analyzed, with low values (high) of AEA-ethmoid bulla distance corresponding to low values (high) of AEA-frontal beak distance. Conclusion The measurements obtained adds anatomical knowledge that can serve as a parameter in frontal and ethmoid sinus surgery. PMID:28382116

Gamma-ray measurements with the segmented gamma scan

International Nuclear Information System (INIS)

Martin, E.R.; Jones, D.F.; Parker, J.L.

1977-12-01

A revised and updated operation and maintenance manual for the segmented gamma-scan instrument is presented, which describes routine assay techniques as well as the theory of operation in sufficient depth that an experienced assayist can make nonroutine assays on a wide variety of materials and samples. In addition, complete electronic and electrical schematics of the Los Alamos Scientific Laboratory (LASL)-designed portions of the system are presented, along with sufficient system and circuit description to facilitate maintenance and troubleshooting. Complete software system descriptions are included, although detailed listings would have to be obained from LASL in order to make machine-language code changes

SU-E-T-561: Development of Depth Dose Measurement Technique Using the Multilayer Ionization Chamber for Spot Scanning Method

International Nuclear Information System (INIS)

Takayanagi, T; Fujitaka, S; Umezawa, M; Ito, Y; Nakashima, C; Matsuda, K

2014-01-01

Purpose: To develop a measurement technique which suppresses the difference between profiles obtained with a multilayer ionization chamber (MLIC) and with a water phantom. Methods: The developed technique multiplies the raw MLIC data by a correction factor that depends on the initial beam range and water equivalent depth. The correction factor is derived based on a Bragg curve calculation formula considering range straggling and fluence loss caused by nuclear reactions. Furthermore, the correction factor is adjusted based on several integrated depth doses measured with a water phantom and the MLIC. The measured depth dose profiles along the central axis of the proton field with a nominal field size of 10 by 10 cm were compared between the MLIC using the new technique and the water phantom. The spread out Bragg peak was 20 cm for fields with a range of 30.6 cm and 6.9 cm. Raw MLIC data were obtained with each energy layer, and integrated after multiplying by the correction factor. The measurements were performed by a spot scanning nozzle at Nagoya Proton Therapy Center, Japan. Results: The profile measured with the MLIC using the new technique is consistent with that of the water phantom. Moreover, 97% of the points passed the 1% dose /1mm distance agreement criterion of the gamma index. Conclusion: We have demonstrated that the new technique suppresses the difference between profiles obtained with the MLIC and with the water phantom. It was concluded that this technique is useful for depth dose measurement in proton spot scanning method

A Scanning Quantum Cryogenic Atom Microscope

Science.gov (United States)

Lev, Benjamin

Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity, high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented DC-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (2 um), or 6 nT / Hz1 / 2 per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly one-hundred points with an effective field sensitivity of 600 pT / Hz1 / 2 each point during the same time as a point-by-point scanner would measure these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly two orders of magnitude improvement in magnetic flux sensitivity (down to 10- 6 Phi0 / Hz1 / 2) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are for the first time carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns and done so using samples that may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge transport images at temperatures from room to \\x9D4K in unconventional superconductors and topologically nontrivial materials.

Relationship between hemodynamic changes of portal vein and hepatic artery measured by color Doppler ultrasound and FibroScan value in patients with liver cirrhosis

Directory of Open Access Journals (Sweden)

CHENG Xiaofei

2014-11-01

Full Text Available ObjectiveTo explore the relationship between hemodynamic changes of the portal vein and hepatic artery measured by color Doppler ultrasound and FibroScan value in patients with liver cirrhosis. MethodsA total of 192 patients with hepatitis B cirrhosis who were admitted to our hospital from March 2010 to December 2013, as well as 100 healthy persons, were recruited. The mean portal vein blood flow velocity (PVVmean, hepatic artery pulsatility index (HAPI, and hepatic artery resistance index (HARI were measured by color Doppler ultrasound. FibroScan was also carried out. All data were statistically analyzed using SPSS 13.0. Continuous data were expressed as mean±SD and compared between groups by t-test. ResultsThe HAPI, HARI, and FibroScan value of the patient group were 1.56±024, 0.73±0.05, and 25.38±7.73, respectively, significantly higher than those of the control group (1.36±0.14, 0.65±0.07, and 7.8±3.6 (P＜0.05; the PVVmean of the patient group was 14.43±1.86, significantly lower than that of the control group (17.35±0.56 (P＜0.05. FibroScan value was positively correlated with HAPI and HARI (r1=0.59, r2=0.66, P＜0.001, but negatively correlated with PVVmean (r=-0.64, P＜0.001. ConclusionThe liver stiffness assessed by FibroScan and the hemodynamic changes of the portal vein and hepatic artery measured by color Doppler ultrasound are vitally important for evaluating the severity of liver cirrhosis.

Advanced HEDL gamma scan system

International Nuclear Information System (INIS)

Smith, F.C.; Olson, R.N.

1983-01-01

The design of an advanced state-of-the-art gamma scan system built for the purpose of measuring the point-by-point gamma activity of irradiated fuel rods is described. The emphasis of the system design was to achieve the highest rate of throughput with the minimum per rod cost while maintaining system accuracy and reliability. Preliminary tests demonstrate that all system requirements were met or exceeded. The system provides improved throughput, precision, automation, flexibility, and data processing capability over previous gamma scan systems

Measurement of thermal conductivity of Bi2Te3 nanowire using high-vacuum scanning thermal wave microscopy

Science.gov (United States)

Park, Kyungbae; Hwang, Gwangseok; Kim, Hayeong; Kim, Jungwon; Kim, Woochul; Kim, Sungjin; Kwon, Ohmyoung

2016-02-01

With the increasing application of nanomaterials in the development of high-efficiency thermoelectric energy conversion materials and electronic devices, the measurement of the intrinsic thermal conductivity of nanomaterials in the form of nanowires and nanofilms has become very important. However, the current widely used methods for measuring thermal conductivity have difficulties in eliminating the influence of interfacial thermal resistance (ITR) during the measurement. In this study, by using high-vacuum scanning thermal wave microscopy (HV-STWM), we propose a quantitative method for measuring the thermal conductivity of nanomaterials. By measuring the local phase lag of high-frequency (>10 kHz) thermal waves passing through a nanomaterial in a high-vacuum environment, HV-STWM eliminates the measurement errors due to ITR and the distortion due to heat transfer through air. By using HV-STWM, we measure the thermal conductivity of a Bi2Te3 nanowire. Because HV-STWM is quantitatively accurate and its specimen preparation is easier than in the thermal bridge method, we believe that HV-STWM will be widely used for measuring the thermal properties of various types of nanomaterials.

In situ measurement of the kinetic friction of ZnO nanowires inside a scanning electron microscope

Energy Technology Data Exchange (ETDEWEB)

Polyakov, Boris, E-mail: boriss.polakovs@ut.ee [Institute of Physics, University of Tartu, Riia st. 142, Tartu (Estonia); Institute of Solid State Physics, University of Latvia, Kengaraga st. 8, Riga (Latvia); Dorogin, Leonid M; Lohmus, Ants [Institute of Physics, University of Tartu, Riia st. 142, Tartu (Estonia); Romanov, Alexey E [Institute of Physics, University of Tartu, Riia st. 142, Tartu (Estonia); Ioffe Physical Technical Institute, RAS, Politehnicheskaja st. 26, St. Petersburg (Russian Federation); Lohmus, Rynno [Institute of Physics, University of Tartu, Riia st. 142, Tartu (Estonia)

2012-01-15

A novel method for measuring the kinetic friction force in situ was developed for zinc oxide nanowires on highly oriented pyrolytic graphite and oxidised silicon wafers. The experiments were performed inside a scanning electron microscope and used a nanomanipulation device as an actuator, which also had an atomic force microscope tip attached to it as a probe. A simple model based on the Timoshenko elastic beam theory was applied to interpret the elastic deformation of a sliding nanowire (NW) and to determine the distributed kinetic friction force.

Note: A quartz cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope measurements.

Science.gov (United States)

Xia, Zhigang; Wang, Jihao; Hou, Yubin; Lu, Qingyou

2014-09-01

In this paper, we provide and demonstrate a design of a unique cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope (ECSTM) measurements. The active metal Pt electrode can be protected from air contamination during the preparation process. The transparency of the cell allows the tip and bead to be aligned by direct observation. Based on this, a new and effective alignment method is introduced. The high-quality bead preparations through this new cell have been confirmed by the ECSTM images of Pt (111).

Numerical comparison of grid pattern diffraction effects through measurement and modeling with OptiScan software

Science.gov (United States)

Murray, Ian B.; Densmore, Victor; Bora, Vaibhav; Pieratt, Matthew W.; Hibbard, Douglas L.; Milster, Tom D.

2011-06-01

Coatings of various metalized patterns are used for heating and electromagnetic interference (EMI) shielding applications. Previous work has focused on macro differences between different types of grids, and has shown good correlation between measurements and analyses of grid diffraction. To advance this work, we have utilized the University of Arizona's OptiScan software, which has been optimized for this application by using the Babinet Principle. When operating on an appropriate computer system, this algorithm produces results hundreds of times faster than standard Fourier-based methods, and allows realistic cases to be modeled for the first time. By using previously published derivations by Exotic Electro-Optics, we compare diffraction performance of repeating and randomized grid patterns with equivalent sheet resistance using numerical performance metrics. Grid patterns of each type are printed on optical substrates and measured energy is compared against modeled energy.

Radiation exposure distribution in patients undergoing CT brain scans

International Nuclear Information System (INIS)

Yang Zhanshan; Feng Dinghua; Chang Zichi; Li Shijun

1989-12-01

The distribution of surface exposures in patients undergoing single and multiple computerized tomographic brain scans with Hitachi CT-W500 was measured by LiF(Mg, Ti) thermoluminescent dosimetry. It was found that there was no significant difference in the sufrace exposures from different scanning slices. However, the exposure doses at different scanning angles around the head were different significantly. The reference point of the maximum surface exposure was at the temporal part of the head. the maximum surface exposure was at 1.65 x 10 -3 C·kg -1 while the average exposure was 1.55 x 10 -3 C·kg -1 . The ratio of the average dose resulting from nine scans to that from a single scan was 1.3, and the surface exposure contribution of scattered radiation was computed. At the same time the radiation doses to eyes, thyroid, chest and gonads of patiens at corresponding position were also measured and were compared with those from CT cranial scans in children and skull radiographic procedures respectively

Fast differential scanning calorimetry of liquid samples with chips

DEFF Research Database (Denmark)

Splinter, R.; van Herwaarden, A. W.; van Wetten, I. A.

2015-01-01

Based on a modified version of standard chips for fast differential scanning calorimetry, DSC of liquid samples has been performed at temperature scan rates of up to 1000 °C/s. This paper describes experimental results with the protein lysozyme, bovine serum, and olive oil. The heating and cooling....... The bovine serum measurements show two main peaks, in good agreement with standard DSC measurements. Olive oil has been measured, with good agreement for the cooling curve and qualitative agreement for the heater curve, compared to DSC measurements....

Maritime Laser Scanning as the Source for Spatial Data

Directory of Open Access Journals (Sweden)

Szulwic Jakub

2015-12-01

Full Text Available The rapid development of scanning technology, especially mobile scanning, gives the possibility to collect spatial data coming from maritime measurement platforms and autonomous manned or unmanned vehicles. Presented solution is derived from the mobile scanning. However we should keep in mind that the specificity of laser scanning at sea and processing collected data should be in the form acceptable in Geographical Information Systems, especially typical for the maritime needs. At the same time we should be aware that data coming from maritime mobile scanning constitutes a new approach to the describing of maritime environment and brings a new perspective that is completely different than air and terrestrial scanning.

A laser sheet self-calibration method for scanning PIV

Science.gov (United States)

Knutsen, Anna N.; Lawson, John M.; Dawson, James R.; Worth, Nicholas A.

2017-10-01

Knowledge of laser sheet position, orientation, and thickness is a fundamental requirement of scanning PIV and other laser-scanning methods. This paper describes the development and evaluation of a new laser sheet self-calibration method for stereoscopic scanning PIV, which allows the measurement of these properties from particle images themselves. The approach is to fit a laser sheet model by treating particles as randomly distributed probes of the laser sheet profile, whose position is obtained via a triangulation procedure enhanced by matching particle images according to their variation in brightness over a scan. Numerical simulations and tests with experimental data were used to quantify the sensitivity of the method to typical experimental error sources and validate its performance in practice. The numerical simulations demonstrate the accurate recovery of the laser sheet parameters over range of different seeding densities and sheet thicknesses. Furthermore, they show that the method is robust to significant image noise and camera misalignment. Tests with experimental data confirm that the laser sheet model can be accurately reconstructed with no impairment to PIV measurement accuracy. The new method is more efficient and robust in comparison with the standard (self-) calibration approach, which requires an involved, separate calibration step that is sensitive to experimental misalignments. The method significantly improves the practicality of making accurate scanning PIV measurements and broadens its potential applicability to scanning systems with significant vibrations.

ComPoScan: Adaptive Scanning for Efficient Concurrent Communications and Positioning with 802.11

DEFF Research Database (Denmark)

King, Thomas; Kjærgaard, Mikkel Baun

2008-01-01

and by validation in several real-world deployments. Results from the emulation show that the system can realize different trade-offs by changing parameters. Furthermore, the emulation shows that the system works independently of the environment, the network card, the signal strength measurement technology......Using 802.11 concurrently for communications and positioning is problematic, especially if location-based services (e.g., indoor navigation) are concurrently executed with real-time applications (e.g., VoIP, video conferencing). Periodical scanning for measuring the signal strength interrupts......, and number and placement of access points. We also show that ComPoScan does not harm the positioning accuracy of a positioning system. By validation in several real-world deployments, we provided evidence for that the real system works as predicted by the emulation. In addition, we provide results for Com...

Automation of BESSY scanning tables

International Nuclear Information System (INIS)

Hanton, J.; Kesteman, J.

1981-01-01

A micro processor M6800 is used for the automation of scanning and premeasuring BESSY tables. The tasks achieved by the micro processor are: 1. control of spooling of the four asynchronous film winding devices and switching on and off the 4 projections lamps, 2. pre-processing of the data coming from a bi-polar coordinates measuring device, 3. bi-directional interchange of informations between the operator, the BESSY table and the DEC PDP 11/34 mini computer controling the scanning operations, 4. control of the magnification on the table by swapping the projection lenses of appropriate focal lengths and the associated light boxes (under development). In connection with point 4, study is being made for the use of BESSY tables for accurate measurements (+/-5 microns), by encoding the displacements of the projections lenses. (orig.)

An interchangeable scanning Hall probe/scanning SQUID microscope

International Nuclear Information System (INIS)

Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

2014-01-01

We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10 −7 T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La 2/3 Ca 1/3 MnO 3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K

Scanning Tunneling Spectroscopy of Potassium on Graphene

Science.gov (United States)

Cormode, Daniel; Leroy, Brian; Yankowitz, Matthew

2012-02-01

We investigate the effect of charged impurities on the electronic properties of large single crystal CVD grown graphene using scanning tunneling microscopy. Mono- and multilayer crystals were prepared by transferring graphene from copper onto exfoliated boron nitride flakes on 300 nm SiO2 substrates. The boron nitride provides an ultra flat surface for the graphene. Potassium atoms are controllably deposited on the graphene at low temperature by heating a nearby getter source. Scanning tunneling spectroscopy and transport measurements were performed in ultra high vacuum at 4.5 K. Transport measurements demonstrate the shifting of the Dirac point as the samples are doped, while STM measurements demonstrate the size, arrangement and local electronic influence of the potassium atoms.

Endoscopic ultrasound duplex scanning for measurement of portal venous flow. Validation against transit time ultrasound flowmetry in pigs

DEFF Research Database (Denmark)

Hansen, E F; Strandberg, C; Bendtsen, F

1999-01-01

with that of transit time ultrasound (TTU) in healthy pigs. The ability of EUS to detect changes in the portal venous flow after pharmacologic intervention was also investigated. METHODS: Six anaesthetized pigs were studied. Portal venous flow was measured simultaneously by EUS duplex scanning, using a Pentax FG-32UA...... echoendoscope connected to a Hitachi EUB 515-A ultrasound scanner, and by TTU with a Cardiomed CM 4000 flowmeter probe placed on the portal vein. Terlipressin, 1 mg, and placebo were administered in a blind, randomized, crossover design. Measurements were taken at base line and 30 min after each drug...

Vibrating wire for beam profile scanning

Directory of Open Access Journals (Sweden)

S. G. Arutunian

1999-12-01

Full Text Available A method that measures the transverse profile (emittance of the bunch by detecting radiation arising at the scattering of the bunch on scanning wire is widely used. In this work information about bunch scattering is obtained by measuring the oscillation frequency of the tightened scanning wire. In such a way, the system of radiation (or secondary particles extraction and measurement can be removed. The entire unit consists of a compact fork with tightened wire and a scanning system. Normal oscillation frequency of a wire depends on wire tension, its geometric parameters, and, in a second approximation, its elastic characteristics. Normal oscillations are generated by interaction of an alternating current through the wire with magnetic field of a permanent magnet. In this case, it is suggested that the magnetic field of the accelerator (field of dipole magnets or quadrupole magnets be used for excitation of oscillations. The dependence of oscillation frequency on beam scattering is determined by several factors, including changes of wire tension caused by transverse force of the beam and influence of beam self-field. Preliminary calculations show that the influence of wire heating will dominate. We have studied strain gauges on the basis of vibrating wire from various materials (tungsten, beryl bronze, and niobium zirconium alloys. A scheme of normal oscillation generation by alternating current in autogeneration circuit with automatic frequency adjustment was selected. A special method of wire fixation and elimination of transverse degrees of freedom allows us to achieve relative stability better than 10^{-5} during several days at a relative resolution of 10^{-6}. Experimental results and estimates of wire heating of existing scanners show that the wire heats up to a few hundred grades, which is enough for measurements. The usage of wire of micrometer thickness diminishes the problem of wire thermalization speed during the scanning of the bunch.

Cross-correlation Doppler global velocimetry (CC-DGV)

Science.gov (United States)

Cadel, Daniel R.; Lowe, K. Todd

2015-08-01

A flow velocimetry method, cross-correlation Doppler global velocimetry (CC-DGV), is presented as a robust, simplified, and high dynamic range implementation of the Doppler global/planar Doppler velocimetry technique. A sweep of several gigahertz of the vapor absorption spectrum is used for each velocity sample, with signals acquired from both Doppler-shifted scattered light within the flow and a non-Doppler shifted reference beam. Cross-correlation of these signals yields the Doppler shift between them, averaged over the duration of the scan. With presently available equipment, velocities from 0 ms-1 to over 3000 ms-1 can notionally be measured simultaneously, making the technique ideal for high speed flows. The processing routine is shown to be robust against large changes in the vapor pressure of the iodine cell, benefiting performance of the system in facilities where ambient conditions cannot be easily regulated. Validation of the system was performed with measurements of a model wind turbine blade boundary layer made in a 1.83 m by 1.83 m subsonic wind tunnel for which laser Doppler velocimetry (LDV) measurements were acquired alongside the CC-DGV results. CC-DGV uncertainties of ±1.30 ms-1, ±0.64 ms-1, and ±1.11 ms-1 were determined for the orthogonal stream-wise, transverse-horizontal, and transverse-vertical velocity components, and root-mean-square deviations of 2.77 ms-1 and 1.34 ms-1 from the LDV validation results were observed for Reynolds numbers of 1.5 million and 2 million, respectively. Volumetric mean velocity measurements are also presented for a supersonic jet, with velocity uncertainties of ±4.48 ms-1, ±16.93 ms-1, and ±0.50 ms-1 for the orthogonal components, and self-validation done by collapsing the data with a physical scaling.

Skin blood flow from gas transport: helium xenon and laser Doppler compared

Energy Technology Data Exchange (ETDEWEB)

Neufeld, G.R.; Galante, S.R.; Whang, J.M.; DeVries, D.; Baumgardner, J.E.; Graves, D.J.; Quinn, J.A.

1988-03-01

A study was designed to compare three independent measures of cutaneous blood flow in normal healthy volunteers: xenon-133 washout, helium flux, and laser velocimetry. All measurements were confined to the volar aspect of the forearm. In a large group of subjects we found that helium flux through intact skin changes nonlinearly with the controlled local skin temperature whereas helium flux through stripped skin, which is directly proportional to skin blood flow, changes linearly with cutaneous temperature over the range 33 degrees to 42 degrees. In a second group of six volunteers we compared helium flux through stripped skin to xenon-133 washout (intact skin) at a skin temperature of 33 degrees, and we found an essentially linear relationship between helium flux and xenon measured blood flow. In a third group of subjects we compared helium flux blood flow (stripped skin) to laser doppler velocimetric (LDV) measurements (intact skin) at adjacent skin sites and found a nonlinear increase in the LDV skin blood flow compared to that determined by helium over the same temperature range. A possible explanation for the nonlinear increases of helium flux through intact skin and of LDV output with increasing local skin temperature is that they reflect more than a change in blood flow. They may also reflect physical changes in the stratum corneum, which alters its diffusional resistance to gas flux and its optical characteristics.

Skin blood flow from gas transport: helium xenon and laser Doppler compared

International Nuclear Information System (INIS)

Neufeld, G.R.; Galante, S.R.; Whang, J.M.; DeVries, D.; Baumgardner, J.E.; Graves, D.J.; Quinn, J.A.

1988-01-01

A study was designed to compare three independent measures of cutaneous blood flow in normal healthy volunteers: xenon-133 washout, helium flux, and laser velocimetry. All measurements were confined to the volar aspect of the forearm. In a large group of subjects we found that helium flux through intact skin changes nonlinearly with the controlled local skin temperature whereas helium flux through stripped skin, which is directly proportional to skin blood flow, changes linearly with cutaneous temperature over the range 33 degrees to 42 degrees. In a second group of six volunteers we compared helium flux through stripped skin to xenon-133 washout (intact skin) at a skin temperature of 33 degrees, and we found an essentially linear relationship between helium flux and xenon measured blood flow. In a third group of subjects we compared helium flux blood flow (stripped skin) to laser doppler velocimetric (LDV) measurements (intact skin) at adjacent skin sites and found a nonlinear increase in the LDV skin blood flow compared to that determined by helium over the same temperature range. A possible explanation for the nonlinear increases of helium flux through intact skin and of LDV output with increasing local skin temperature is that they reflect more than a change in blood flow. They may also reflect physical changes in the stratum corneum, which alters its diffusional resistance to gas flux and its optical characteristics

A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

Directory of Open Access Journals (Sweden)

Tobias Meier

2015-02-01

Full Text Available We describe an atomic force microscope (AFM for the characterization of self-sensing tunneling magnetoresistive (TMR cantilevers. Furthermore, we achieve a large scan-range with a nested scanner design of two independent piezo scanners: a small high resolution scanner with a scan range of 5 × 5 × 5 μm3 is mounted on a large-area scanner with a scan range of 800 × 800 × 35 μm3. In order to characterize TMR sensors on AFM cantilevers as deflection sensors, the AFM is equipped with a laser beam deflection setup to measure the deflection of the cantilevers independently. The instrument is based on a commercial AFM controller and capable to perform large-area scanning directly without stitching of images. Images obtained on different samples such as calibration standard, optical grating, EPROM chip, self-assembled monolayers and atomic step-edges of gold demonstrate the high stability of the nested scanner design and the performance of self-sensing TMR cantilevers.

A near-field scanning microwave microscope based on a superconducting resonator for low power measurements.

Science.gov (United States)

de Graaf, S E; Danilov, A V; Adamyan, A; Kubatkin, S E

2013-02-01

We report on the design and performance of a cryogenic (300 mK) near-field scanning microwave microscope. It uses a microwave resonator as the near-field sensor, operating at a frequency of 6 GHz and microwave probing amplitudes down to 100 μV, approaching low enough photon population (N ∼ 1000) of the resonator such that coherent quantum manipulation becomes feasible. The resonator is made out of a miniaturized distributed fractal superconducting circuit that is integrated with the probing tip, micromachined to be compact enough such that it can be mounted directly on a quartz tuning-fork, and used for parallel operation as an atomic force microscope (AFM). The resonator is magnetically coupled to a transmission line for readout, and to achieve enhanced sensitivity we employ a Pound-Drever-Hall measurement scheme to lock to the resonance frequency. We achieve a well localized near-field around the tip such that the microwave resolution is comparable to the AFM resolution, and a capacitive sensitivity down to 6.4 × 10(-20) F/Hz, limited by mechanical noise. We believe that the results presented here are a significant step towards probing quantum systems at the nanoscale using near-field scanning microwave microscopy.

Fully-automated computer-assisted method of CT brain scan analysis for the measurement of cerebrospinal fluid spaces and brain absorption density

Energy Technology Data Exchange (ETDEWEB)

Baldy, R.E.; Brindley, G.S.; Jacobson, R.R.; Reveley, M.A.; Lishman, W.A.; Ewusi-Mensah, I.; Turner, S.W.

1986-03-01

Computer-assisted methods of CT brain scan analysis offer considerable advantages over visual inspection, particularly in research; and several semi-automated methods are currently available. A new computer-assisted program is presented which provides fully automated processing of CT brain scans, depending on ''anatomical knowledge'' of where cerebrospinal fluid (CSF)-containing spaces are likely to lie. After identifying these regions of interest quantitative estimates are then provided of CSF content in each slice in cisterns, ventricles, Sylvian fissure and interhemispheric fissure. Separate measures are also provided of mean brain density in each slice. These estimates can be summated to provide total ventricular and total brain volumes. The program shows a high correlation with measures derived from mechanical planimetry and visual grading procedures, also when tested against a phantom brain of known ventricular volume. The advantages and limitations of the present program are discussed.

Bio-physical effects of scanned proton beams: measurements and models for discrete high dose rates scanning systems

International Nuclear Information System (INIS)

De-Marzi, Ludovic

2016-01-01

The main objective of this thesis is to develop and optimize algorithms for intensity modulated proton therapy, taking into account the physical and biological pencil beam properties. A model based on the summation and fluence weighted division of the pencil beams has been used. A new parameterization of the lateral dose distribution has been developed using a combination of three Gaussian functions. The algorithms have been implemented into a treatment planning system, then experimentally validated and compared with Monte Carlo simulations. Some approximations have been made and validated in order to achieve reasonable calculation times for clinical purposes. In a second phase, a collaboration with Institut Curie radiobiological teams has been started in order to implement radiobiological parameters and results into the optimization loop of the treatment planning process. Indeed, scanned pencil beams are pulsed and delivered at high dose rates (from 10 to 100 Gy/s), and the relative biological efficiency of protons is still relatively unknown given the wide diversity of use of these beams: the different models available and their dependence with linear energy transfers have been studied. A good agreement between dose calculations and measurements (deviations lower than 3 % and 2 mm) has been obtained. An experimental protocol has been set in order to qualify pulsed high dose rate effects and preliminary results obtained on one cell line suggested variations of the biological efficiency up to 10 %, though with large uncertainties. (author) [fr

HOVE-Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data

Directory of Open Access Journals (Sweden)

Helmut Panholzer

2018-02-01

Full Text Available Terrestrial laser scanning has become an important surveying technique in many fields such as natural hazard assessment. To analyse earth surface processes, it is useful to generate a digital terrain model originated from laser scan point cloud data. To determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. In mountainous terrain with a small-structured topography, filtering is very difficult. Here, automatic filtering solutions usually designed for airborne laser scan data often lead to unsatisfactory results. In this work, we further develop an existing approach for automated filtering of terrestrial laser scan data, which is based on the assumption that no other surface point can be located in the area above a direct line of sight between scanner and another measured point. By taking into account several environmental variables and a repetitive calculation method, the modified method leads to significantly better results. The root-mean-square-error (RSME for the same test measurement area could be reduced from 5.284 to 1.610. In addition, a new approach for filtering and interpolation of terrestrial laser scanning data is presented using a grid with horizontal and vertical angular data and the measurement length.

SU-F-I-32: Organ Doses from Pediatric Head CT Scan

Energy Technology Data Exchange (ETDEWEB)

Liu, H; Liu, Q; Qiu, J; Zhuo, W [Institute of Radiation Medicine Fudan University, Shanghai (China); Majer, M; Knezevic, Z; Miljanic, S [Radiation Chemistry and Dosimetry Laboratory, Ruder Boskovic Institute, Zagreb (Croatia); Hrsak, H [Clinical Hospital Centre Zagreb, Zagreb (Croatia)

2016-06-15

Purpose: To evaluate the organ doses of pediatric patients who undergoing head CT scan using Monte Carlo (MC) simulation and compare it with measurements in anthropomorphic child phantom.. Methods: A ten years old children voxel phantom was developed from CT images, the voxel size of the phantom was 2mm*2mm*2mm. Organ doses from head CT scan were simulated using MCNPX software, 180 detectors were placed in the voxel phantom to tally the doses of the represented tissues or organs. When performing the simulation, 120 kVp and 88 mA were selected as the scan parameters. The scan range covered from the top of the head to the end of the chain, this protocol was used at CT simulator for radiotherapy. To validate the simulated results, organ doses were measured with radiophotoluminescence (RPL) detectors, placed in the 28 organs of the 10 years old CIRS ATOM phantom. Results: The organ doses results matched well between MC simulation and phantom measurements. The eyes dose was showed to be as expected the highest organ dose: 28.11 mGy by simulation and 27.34 mGy by measurement respectively. Doses for organs not included in the scan volume were much lower than those included in the scan volume, thymus doses were observed more than 10 mGy due the CT protocol for radiotherapy covered more body part than routine head CT scan. Conclusion: As the eyes are superficial organs, they may receive the highest radiation dose during the CT scan. Considering the relatively high radio sensitivity, using shielding material or organ based tube current modulation technique should be encouraged to reduce the eye radiation risks. Scan range was one of the most important factors that affects the organ doses during the CT scan. Use as short as reasonably possible scan range should be helpful to reduce the patient radiation dose. This work was supported by the National Natural Science Foundation of China(11475047)

Radioisotope spleen scan in patients with splenic injury

International Nuclear Information System (INIS)

Mishalany, H.G.; Miller, J.H.; Woolley, M.M.

1982-01-01

The technetium /sup 99m/Tc sulfur colloid liver-spleen scan is a valuable aid in diagnosis and treatment of patients with splenic injury. After reviewing the charts of 47 patients who were ill as a result of splenic trauma, we came to the following conclusions: (1) the scan identified the injury, accurately mapped its extent, and indicated the presence or absence of associated liver injuries; (2) the scans were useful in following the extent and rate of healing of the splenic injury; (3) the scan is an indirect measurement of of return of splenic fuction; (4) the procedure can be performed in a reasonable time frame with no serious morbidity; and (5) the indications, contraindications, and timing of scans are now reasonably well established

Radioisotope spleen scan in patients with splenic injury

Energy Technology Data Exchange (ETDEWEB)

Mishalany, H.G.; Miller, J.H.; Woolley, M.M.

1982-09-01

The technetium /sup 99m/Tc sulfur colloid liver-spleen scan is a valuable aid in diagnosis and treatment of patients with splenic injury. After reviewing the charts of 47 patients who were ill as a result of splenic trauma, we came to the following conclusions: (1) the scan identified the injury, accurately mapped its extent, and indicated the presence or absence of associated liver injuries; (2) the scans were useful in following the extent and rate of healing of the splenic injury; (3) the scan is an indirect measurement of of return of splenic fuction; (4) the procedure can be performed in a reasonable time frame with no serious morbidity; and (5) the indications, contraindications, and timing of scans are now reasonably well established.

An interchangeable scanning Hall probe/scanning SQUID microscope

Energy Technology Data Exchange (ETDEWEB)

Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Tse-Jun; Wang, M. J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2014-08-15

We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.

Effect of Scanning and Reconstruction Parameters on Three Dimensional Volume and CT Value Measurement of Pulmonary Nodules: A Phantom Study

Directory of Open Access Journals (Sweden)

Datong SU

2017-08-01

Full Text Available Background and objective The computed tomography (CT follow-up of indeterminate pulmonary nodules aiming to evaluate the change of the volume and CT value is the common strategy in clinic. The CT dose needs to considered on serious CT scans in addition to the measurement accuracy. The purpose of this study is to quantify the precision of pulmonary nodule volumetric measurement and CT value measurement with various tube currents and reconstruction algorithms in a phantom study with dual-energy CT. Methods A chest phantom containing 9 artificial spherical solid nodules with known diameter (D=2.5 mm, 5 mm, 10 mm and density (-100 HU, 60 HU and 100 HU was scanned using a 64-row detector CT canner at 120 Kilovolt & various currents (10 mA, 20 mA, 50 mA, 80 mA,100 mA, 150 mA and 350 mA. Raw data were reconstructed with filtered back projection and three levels of adaptive statistical iterative reconstruction algorithm (FBP, ASIR; 30%, 50% and 80%. Automatic volumetric measurements were performed using commercially available software. The relative volume error (RVE and the absolute attenuation error (AAE between the software measures and the reference-standard were calculated. Analyses of the variance were performed to evaluate the effect of reconstruction methods, different scan parameters, nodule size and attenuation on the RPE. Results The software substantially overestimated the very small (D=2.5 mm nodule's volume [mean RVE: (100.8%±28%] and underestimated it attenuation [mean AAE: (-756±80 HU]. The mean RVEs of nodule with diameter as 5 mm and 10 mm were small [(-0.9%±1.1% vs (0.9%±1.4%], however, the mean AAEs [(-243±26 HU vs (-129±7 HU] were large. The ANOVA analysis for repeated measurements showed that different tube current and reconstruction algorithm had no significant effect on the volumetric measurements for nodules with diameter of 5 mm and 10 mm (F=5.60, P=0.10 vs F=11.13, P=0.08, but significant effects on the measurement of CT

Concept and development of measurement method of time sensitivity profile (TSP) in X-ray CT. Comparison of non-helical, single-slice helical, and multi-slice helical scans

International Nuclear Information System (INIS)

Tsujioka, Katsumi; Ida, Yoshihiro; Ohtsubo, Hironori; Takahashi, Yasukata; Niwa, Masayoshi

2000-01-01

We focused on the time element contained in a single CT image, and devised the concept of a time-sensitivity profile (TSP) describing how the time element is translated into an image. We calculated the data collection time range when the helical pitch is changed in non helical scans, single slice helical scans, and multi slice helical scans. We then calculated the time sensitivity profile (TSP) from the weighting applied when the data collection time range is translated into an image. TSP was also measured for each scanning method using our self-made moving phantom. TSPs obtained from the calculation and the experiments were very close. TSP showed interesting characteristics with each scanning method, especially in the case of multi slice helical scanning, in which TSP became shorter as helical pitch increased. We referred to the TSP's FWHM as the effective scanning time. When we conducted multi slice helical scanning at helical pitch 3, the effective scanning time increased to about 24% longer than that of a non helical scan. When we conducted multi slice helical scanning at helical pitch 5 or 6, the effective scanning time was about half that of a non helical scan. The time sensitivity profile (TSP) is a totally new concept that we consider an important element in discussing the time resolution of a CT scanner. The results of this review will provide significant data in determining the scanning parameters when scanning a moving object. (author)

NEW SCANNING DEVICE FOR SCANNING TUNNELING MICROSCOPE APPLICATIONS

NARCIS (Netherlands)

SAWATZKY, GA; Koops, Karl Richard

A small, single piezo XYZ translator has been developed. The device has been used as a scanner for a scanning tunneling microscope and has been tested successfully in air and in UHV. Its simple design results in a rigid and compact scanning unit which permits high scanning rates.

Application of terrestrial laser scanning for measuring tree crown structures

International Nuclear Information System (INIS)

Pretzsch, H.; Seifert, S.; Huang, P.

2011-01-01

This paper addresses the potential of terrestrial laser scanning (TLS) for describing and modelling of tree crown structure and dynamics. We first present a general approach for the metabolic and structural scaling of tree crowns. Out of this approach we emphasize those normalization and scaling parameters which become accessible by TLS. For example we show how the individual tree leaf area index, convex hull, and its space-filling by leaves can be extracted out of laser scan data. This contributes to a theoretical and empirical substantiation of crown structure models which were missing so far for e.g. quantification of structural and species diversity in forest stands, inventory of crown biomass, species detection by remote sensing, and understanding of self- and alien-thinning in pure and mixed stands. Up to now works on this topic delivered a rather scattered empirical knowledge mainly by single inventories of trees and stands. In contrast, we recommend to start with a model approach, and to complete existing data with repeated TLS inventories in order to come to a consistent and theoretically based model of tree crowns. (author) [de

High throughput, parallel scanning probe microscope for nanometrology and nanopatterning applications

NARCIS (Netherlands)

Sadeghian Marnani, H.; Paul, P.C.; Herfst, R.W.; Dekker, A.; Winters, J.; Maturova, K.

2017-01-01

Scanning Probe microscope (SPM) is an important nanoinstrument for several applications such as bioresearch, metrology, inspection and nanopatterning. Single SPM is associated with relatively slow rate of scanning and low throughput measurement, thus not being suitable for scanning large samples

An optical scanning subsystem for a UAS-enabled hyperspectral radiometer

Data.gov (United States)

National Aeronautics and Space Administration — Hyperspectral radiometers will be integrated with an optical scanning subsystem to measure remote sensing reflectance spectra over the ocean.  The entire scanning...

Nuclear Scans

Science.gov (United States)

Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

Single-photon compressive imaging with some performance benefits over raster scanning

International Nuclear Information System (INIS)

Yu, Wen-Kai; Liu, Xue-Feng; Yao, Xu-Ri; Wang, Chao; Zhai, Guang-Jie; Zhao, Qing

2014-01-01

A single-photon imaging system based on compressed sensing has been developed to image objects under ultra-low illumination. With this system, we have successfully realized imaging at the single-photon level with a single-pixel avalanche photodiode without point-by-point raster scanning. From analysis of the signal-to-noise ratio in the measurement we find that our system has much higher sensitivity than conventional ones based on point-by-point raster scanning, while the measurement time is also reduced. - Highlights: • We design a single photon imaging system with compressed sensing. • A single point avalanche photodiode is used without raster scanning. • The Poisson shot noise in the measurement is analyzed. • The sensitivity of our system is proved to be higher than that of raster scanning

The selection of window width and levels for measuring the airway dimensions with spiral CT scan: an experimental study in Japanese white big-ear rabbits

International Nuclear Information System (INIS)

Han Xinwei; Lu Huuibing; Wu Gang; Ma Ji; Wang Nan; Si Jiangtao

2009-01-01

Objective: To investigate the optimal window width and window level for measuring the airway dimensions with spiral CT scan in Japanese white big-ear rabbits so as to lay the foundation for airway stenting in animal experiments. Methods: Multi-slice spiral CT scanning of cervico-thoracic region was performed in 30 healthy adult Japanese white big-ear rabbits, the anteroposterior and transversal diameter of the thoracic trachea, the anteroposterior diameter of the right and left bronchus were measured with lung window, mediastinum window and special fat window separately. The revealing rate of the tracheal wall and the measuring results in different windows and levels were recorded and compared with the anatomical data. The differences of the relevant data were statistically analyzed. Results: With lung window, the tracheal wall was well demonstrated, but the relevant data were smaller than that with mediastinum window. With mediastinum window, the data were bigger and the tracheal wall border appeared blurred. The results obtained with fat window were close to the actual anatomical data. Conclusion: For accurately measuring the anteroposterior and transversal diameter of the thoracic trachea in Japanese white big-ear rabbits with multi- slice spiral CT scan, fat window should be adopted, which is helpful for the preparation of tracheal and bronchial stents. (authors)

The accuracy of three-dimensional fused deposition modeling (FDM) compared with three-dimensional CT-Scans on the measurement of the mandibular ramus vertical length, gonion-menton length, and gonial angle

Science.gov (United States)

Savitri, I. T.; Badri, C.; Sulistyani, L. D.

2017-08-01

Presurgical treatment planning plays an important role in the reconstruction and correction of defects in the craniomaxillofacial region. The advance of solid freeform fabrication techniques has significantly improved the process of preparing a biomodel using computer-aided design and data from medical imaging. Many factors are implicated in the accuracy of the 3D model. To determine the accuracy of three-dimensional fused deposition modeling (FDM) models compared with three-dimensional CT scans in the measurement of the mandibular ramus vertical length, gonion-menton length, and gonial angle. Eight 3D models were produced from the CT scan data (DICOM file) of eight patients at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Indonesia, Cipto Mangunkusumo Hospital. Three measurements were done three times by two examiners. The measurements of the 3D CT scans were made using OsiriX software, while the measurements of the 3D models were made using a digital caliper and goniometry. The measurement results were then compared. There is no significant difference between the measurements of the mandibular ramus vertical length, gonion-menton length, and gonial angle using 3D CT scans and FDM 3D models. FDM 3D models are considered accurate and are acceptable for clinical applications in dental and craniomaxillofacial surgery.

Demonstration of PIV in a Transonic Compressor

Science.gov (United States)

Wernet, Mark P.

1998-01-01

Particle Imaging Velocimetry (PIV) is a powerful measurement technique which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. PIV data are measured simultaneously at multiple points in space, which enables the investigation of the non-stationary spatial structures typically encountered in turbomachinery. Many of the same issues encountered in the application of LDV techniques to rotating machinery apply in the application of PIV. Preliminary results from the successful application of the standard 2-D PIV technique to a transonic axial compressor are presented. The lessons learned from the application of the 2-D PIV technique will serve as the basis for applying 3-component PIV techniques to turbomachinery.

Validation of measurements of Fourier phase and amplitude analysis of technetium99 gated cardiac scans using artificial hearts

International Nuclear Information System (INIS)

Yiannikas, J.; Takatani, S.; MacIntyre, W.J.; Underwood, D.A.; Cook, S.A.; Go, R.T.; Napoli, C.; Nose, Y.

1982-01-01

The use of artificial hearts, developed for total heart replacement programs, allows assessment of the accuracy of measuring the first Fourier component phase and amplitude when applied to gated cardiac technetium 99 scans. In the extreme example of asynchrony of ventricular contraction in coronary artery disease that of ventricular aneurysms, the first Fourier component measurements of amplitude were highly correlated to volume increases suggesting that the calculated amplitude accurately reflects volume changes. The calculated asynchrony using Fourier analysis of the gated technetium 99 studies of two artificial hearts was highly accurate when compared to the predetermined calculation of phase angle difference and hence degree of asynchrony. The studies suggest that measurement of phase and amplitude using the first Fourier component of time-activity waves of gated cardiac technetium 99 studies accurately measure degree of asynchrony and volume changes respectively

Laser scanning of experimental solar cells

Science.gov (United States)

Plunkett, B. C.; Lasswell, P. G.

1980-01-01

A description is presented of a laser scanning instrument which makes it possible to display and measure the spatial response of a solar cell. Examples are presented to illustrate the use of generated micrographs in the isolation of flaws and features of the cell. The laser scanner system uses a 4 mW, CW helium-neon laser, operating a wavelength of 0.633 micrometers. The beam is deflected by two mirror galvanometers arranged to scan in orthogonal directions. After being focused on the solar cell by the beam focusing lens, the moving light spot raster scans the specimen. The current output of the photovoltaic device under test, as a function of the scan dot position, can be displayed in several modes. The laser scanner has proved to be a very useful diagnostic tool in optimizing the process design of transparent metal film photovoltaic devices on Zn3P2, a relatively new photovoltaic material.

Indirect measurement of the magnetocaloric effect using a novel differential scanning calorimeter with magnetic field.

Science.gov (United States)

Jeppesen, S; Linderoth, S; Pryds, N; Kuhn, L Theil; Jensen, J Buch

2008-08-01

A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very fast and accurate heat capacity measurements under magnetic field to be made. The device was validated from heat capacity measurements for the typical DSC reference material gallium (Ga) and a La(0.67)Ca(0.33)MnO(3) manganite system and the results were highly consistent with previous reported data for these materials. The DSC has a working range from 200 to 340 K and has been tested in magnetic fields reaching 1.8 T. The signal-to-noise ratio is in the range of 10(2)-10(3) for the described experiments. Finally the results have been compared to results from a Quantum Design(R) physical properties measuring system. The configuration of the system also has the advantage of being able to operate with other types of magnets, e.g., permanent magnets or superconducting coils, as well as the ability to be expanded to a wider temperature range.

Glass transition of anhydrous starch by fast scanning calorimetry.

Science.gov (United States)

Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson

2017-10-01

By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.

CFD simulation and validation of turbulent mixing in a rod bundle with vaned spacer grids based on LDV test

International Nuclear Information System (INIS)

Chen Xi; Li Songwei; Li Zhongchun; Du Sijia; Zhang Yu; Peng Huanhuan

2017-01-01

Spacer grids with mixing vanes are generally used in fuel assemblies of Pressurized Water Reactor (PWR), because that mixing vanes could enhance the lateral turbulent mixing in subchannels. Thus, heat exchangements are more efficient, and the value of departure from nucleate boiling (DNB) is greatly increased. Actually turbulent mixing is composed of two kinds of flows: swirling flow inside the subchannel and cross flow between subchannels. Swirling flow could induce mixing between hot water near the rod and cold water in the center of the subchannel, and may accelerate deviation of the bubbles from the rod surface. Besides, crossing flow help to mixing water between hot subchannels and cold subchannels, which impact relatively large flow area. As a result, how to accurately capture and how to predict the complicated mixing phenomenon are of great concernments. Recently many experimental studies has been conducted to provide detailed turbulent mixing in rod bundle, among which Laser Doppler Velocimetry method is widely used. With great development of Computational Fluid Dynamics, CFD has been validated as an analysis method for nuclear engineering, especially for single phase calculation. This paper presents the CFD simulation and validation of the turbulent mixing induced by spacer grid with mixing vanes in rod bundles. Experiment data used for validation came from 5 x 5 rod bundle test with LDV technology, which is organized by Science and Technology on Reactor System Design Technology Laboratory. A 5 x 5 rod bundle with two spacer grids were used. Each rod has dimension of 9.5 mm in outer diameter and distance between rods is 12.6 mm. Two axial bulk velocities were conducted at 3.0 m/s for high Reynolds number and 1.0 m/s for low Reynolds number. Working pressure was 1.0 bar, and temperature was about 25degC. Two different distances from the downstream of the mixing spacer grid and one from upstream were acquired. Mean axial velocities and turbulent intensities

Measurements of Epidural Space Depth Using Preexisting CT Scans Correlate with Loss of Resistance Depth during Thoracic Epidural Catheter Placement

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Nathaniel H. Greene

2015-01-01

Full Text Available Background. Thoracic epidural catheters provide the best quality postoperative pain relief for major abdominal and thoracic surgical procedures, but placement is one of the most challenging procedures in the repertoire of an anesthesiologist. Most patients presenting for a procedure that would benefit from a thoracic epidural catheter have already had high resolution imaging that may be useful to assist placement of a catheter. Methods. This retrospective study used data from 168 patients to examine the association and predictive power of epidural-skin distance (ESD on computed tomography (CT to determine loss of resistance depth acquired during epidural placement. Additionally, the ability of anesthesiologists to measure this distance was compared to a radiologist, who specializes in spine imaging. Results. There was a strong association between CT measurement and loss of resistance depth (P35 changed this relationship (P=0.007. The ability of anesthesiologists to make CT measurements was similar to a gold standard radiologist (all individual ICCs>0.9. Conclusions. Overall, this study supports the examination of a recent CT scan to aid in the placement of a thoracic epidural catheter. Making use of these scans may lead to faster epidural placements, fewer accidental dural punctures, and better epidural blockade.

Efficiency of a concentric matrix track detector surface scanning

International Nuclear Information System (INIS)

Bek-Uzarov, Dj.; Nikezic, D.; Kostic, D.; Krstic, D.; Cuknic, O.

1995-01-01

Heavy particle ionizing radiation track counting on the surface of a solid state round surface detector is made using the microscope and scanning step by step by a round field of vision. The whole solid state detector surface could not be fully or completely covered by round fields of visions. Therefore detector surface could be divided on the two parts, the larger surface, being under fields of vision, really scanned and no scanned missed or omitted surface. The ratio between omitted and scanned surfaces is so called track scanning efficiency. The knowledge of really counted, or scanned surface is a important value for evaluating the real surface track density an exposed solid state track detector. In the paper a matrix of a concentric field of vision made around the first microscope field of vision placed in center of the round disc of the scanned track detector is proposed. In a such scanning matrix the real scanned surface could be easy calculated and by the microscope scanning made as well. By this way scanned surface is very precisely obtained as well. Precise knowledge of scanned and omitted surface allows to obtain more precise scanning efficiency factor as well as real surface track density, the main parameter in solid state track detection measurements. (author)

Estimation of absorbed doses from paediatric cone-beam CT scans: MOSFET measurements and Monte Carlo simulations.

Science.gov (United States)

Kim, Sangroh; Yoshizumi, Terry T; Toncheva, Greta; Frush, Donald P; Yin, Fang-Fang

2010-03-01

The purpose of this study was to establish a dose estimation tool with Monte Carlo (MC) simulations. A 5-y-old paediatric anthropomorphic phantom was computed tomography (CT) scanned to create a voxelised phantom and used as an input for the abdominal cone-beam CT in a BEAMnrc/EGSnrc MC system. An X-ray tube model of the Varian On-Board Imager((R)) was built in the MC system. To validate the model, the absorbed doses at each organ location for standard-dose and low-dose modes were measured in the physical phantom with MOSFET detectors; effective doses were also calculated. In the results, the MC simulations were comparable to the MOSFET measurements. This voxelised phantom approach could produce a more accurate dose estimation than the stylised phantom method. This model can be easily applied to multi-detector CT dosimetry.

Cost-utility analysis of ledipasvir/sofosbuvir for the treatment of genotype 1 chronic hepatitis C in Japan.

Science.gov (United States)

Igarashi, Ataru; Tang, Wentao; Guerra, Ines; Marié, Lucile; Cure, Sandrine; Lopresti, Michael

2017-01-01

Hepatitis C is the result of a ribonucleic acid (RNA) virus (hepatitis C virus; HCV). The Japan Society of Hepatology (JSH) estimated that 1.5-2 million people in Japan carry HCV. Six major HCV genotypes (GT) and a large number of subtypes have been described in the literature. In Japan, around 70% to 80% of people are infected with HCV genotype 1b. The progress of the disease primarily affects the liver and may lead to liver cirrhosis, hepatocellular carcinoma (HCC) and death. Sofosbuvir (SOF) is a nucleotide analogue NS5B inhibitor and ledipasvir (LDV) is an inhibitor of the HCV NS5A protein. They are combined in a single tablet regimen for the treatment of GT1 patients and resulted in sustained virological response (SVR) above 94% in large phase III trials. This analysis assesses the cost-utility of LDV/SOF in GT1 patients in Japan. A cohort of 10,000 patients was followed through a Markov model until they reached 100 years of age. GT1 treatment-naïve and experienced, non-cirrhotic and cirrhotic patients were studied separately. LDV/SOF was compared to several treatment regimens containing pegylated interferon (PEGIFN), telaprevir (TVR), simeprevir (SMV), daclatasvir (DCV), asunaprevir (ASV) and ribavirin (RBV). Discount rates of 2% were applied to costs and outcomes according to the Japanese guidelines. LDV/SOF was cost-effective against most comparators with incremental cost-effectiveness ratios (ICERs) below JPY 5,000,000. By applying a societal perspective, LDV/SOF was the dominant treatment strategy in all cases. Moreover, LDV/SOF reduced the number of cases of advanced liver disease. These results were robust to sensitivity analyses. LDV/SOF was cost-effective compared to most of the currently recommended treatments. Furthermore, LDV/SOF extends treatments to HCV-infected patients who are ineligible for interferon and RBV-based regimens. LDV/SOF thus has the potential to help reduce the burden of HCV in Japan.

Acceptability, Precision and Accuracy of 3D Photonic Scanning for Measurement of Body Shape in a Multi-Ethnic Sample of Children Aged 5-11 Years: The SLIC Study.

Directory of Open Access Journals (Sweden)

Jonathan C K Wells

Full Text Available Information on body size and shape is used to interpret many aspects of physiology, including nutritional status, cardio-metabolic risk and lung function. Such data have traditionally been obtained through manual anthropometry, which becomes time-consuming when many measurements are required. 3D photonic scanning (3D-PS of body surface topography represents an alternative digital technique, previously applied successfully in large studies of adults. The acceptability, precision and accuracy of 3D-PS in young children have not been assessed.We attempted to obtain data on girth, width and depth of the chest and waist, and girth of the knee and calf, manually and by 3D-PS in a multi-ethnic sample of 1484 children aged 5-11 years. The rate of 3D-PS success, and reasons for failure, were documented. Precision and accuracy of 3D-PS were assessed relative to manual measurements using the methods of Bland and Altman.Manual measurements were successful in all cases. Although 97.4% of children agreed to undergo 3D-PS, successful scans were only obtained in 70.7% of these. Unsuccessful scans were primarily due to body movement, or inability of the software to extract shape outputs. The odds of scan failure, and the underlying reason, differed by age, size and ethnicity. 3D-PS measurements tended to be greater than those obtained manually (p 0.90 for most outcomes.3D-PS is acceptable in children aged ≥ 5 years, though with current hardware/software, and body movement artefacts, approximately one third of scans may be unsuccessful. The technique had poorer technical success than manual measurements, and had poorer precision when the measurements were viable. Compared to manual measurements, 3D-PS showed modest average biases but acceptable limits of agreement for large surveys, and little evidence that bias varied substantially with size. Most of the issues we identified could be addressed through further technological development.

Brain PET scan

Science.gov (United States)

... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

Some practical aspects of dual-energy CT scanning

Energy Technology Data Exchange (ETDEWEB)

Dunscombe, P.B.; Katz, D.E.; Stacey, A.J. (Charing Cross Group of Hospitals, London (UK))

1984-01-01

Using the dual-energy scanning method developed by Brooks (1977), and making slow x-ray scans at 100 kVp, 35 mA and 140 kVp, 20 mA, measurements were made of electron density and effective atomic number in the lumbar spines of 36 patients aged from 22 to 87 years, and not known to be suffering from conditions which result in osteoporosis or osteomalacia. The authors discuss in detail the sources of experimental error which contributed to the large measured spread of normal values of electron density and effective atomic number.

Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques

Energy Technology Data Exchange (ETDEWEB)

Fan, K-C [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chen, L-C [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd, Taipei, 106, Taiwan (China); Lin, C-D [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chang, Calvin C [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Kuo, C-F [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Chou, J-T [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China)

2005-01-01

The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3-5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved.

Deriving structural forest parameters using airborne laser scanning

International Nuclear Information System (INIS)

Morsdorf, F.

2011-01-01

Airborne laser scanning is a relatively young and precise technology to directly measure surface elevations. With today's high scanning rates, dense 3-D pointclouds of coordinate triplets (xyz) can be provided, in which many structural aspects of the vegetation are contained. The challenge now is to transform this data, as far as possible automatically, into manageable information relevant to the user. In this paper we present two such methods: the first extracts automatically the geometry of individual trees, with a recognition rate of over 70% and a systematic underestimation of tree height of only 0.6 metres. The second method derives a pixel map of the canopy density from the pointcloud, in which the spatial patterns of vegetation cover are represented. These patterns are relevant for habitat analysis and ecosystem studies. The values derived by this method correlate well with field measurements, giving a measure of certainty (R 2 ) of 0.8. The greatest advantage of airborne laser scanning is that it provides spatially extensive, direct measurements of vegetation structure which show none of the extrapolation errors of spot measurements. A large challenge remains in integrating these new products into the user's processing chains and workflows, be it in the realm of forestry or in that of ecosystem research. (author) [de

Gamma scanning of the irradiated HANARO fuels

International Nuclear Information System (INIS)

Hong, Kwon Pyo; Lee, K. S.; Park, D. G.; Baik, S. Y.; Song, W. S.; Kim, T. Y.; Seo, C. K.

1997-02-01

To conform the burnup state of the fuels, we have transported the irradiated HANARO fuels from the reactor to IMEF (Irradiated Material Examination Facility), and executed gamma scanning for the fuels. By measuring the gamma-rays from the irradiated fuels we could see the features of the relative burnup distributions in the fuel bundles. All of 17 fuel bundles were taken in and out between HANARO and IMEF from March till August in 1996, and we carried out the related regulations. Longitudinal gamma scanning and angular gamma scanning are done for each fuel bundle without dismantlement of the bundles. (author). 5 tabs., 25 figs

Radionuclide scanning

International Nuclear Information System (INIS)

Shapiro, B.

1986-01-01

Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial

The Photosensitivity of Rhodopsin Bleaching and Light-Induced Increases of Fundus Reflectance in Mice Measured In Vivo With Scanning Laser Ophthalmoscopy

Science.gov (United States)

Zhang, Pengfei; Goswami, Mayank; Zawadzki, Robert J.; Pugh, Edward N.

2016-01-01

Purpose To quantify bleaching-induced changes in fundus reflectance in the mouse retina. Methods Light reflected from the fundus of albino (Balb/c) and pigmented (C57Bl/6J) mice was measured with a multichannel scanning laser ophthalmoscopy optical coherence tomography (SLO-OCT) optical system. Serial scanning of small retinal regions was used for bleaching rhodopsin and measuring reflectance changes. Results Serial scanning generated a saturating reflectance increase centered at 501 nm with a photosensitivity of 1.4 × 10−8 per molecule μm2 in both strains, 2-fold higher than expected were irradiance at the rod outer segment base equal to that at the retinal surface. The action spectrum of the reflectance increase corresponds to the absorption spectrum of mouse rhodopsin in situ. Spectra obtained before and after bleaching were fitted with a model of fundus reflectance, quantifying contributions from loss of rhodopsin absorption with bleaching, absorption by oxygenated hemoglobin (HbO2) in the choroid (Balb/c), and absorption by melanin (C57Bl/6J). Both mouse strains exhibited light-induced broadband reflectance changes explained as bleaching-induced reflectivity increases at photoreceptor inner segment/outer segment (IS/OS) junctions and OS tips. Conclusions The elevated photosensitivity of rhodopsin bleaching in vivo is explained by waveguide condensing of light in propagation from rod inner segment (RIS) to rod outer segment (ROS). The similar photosensitivity of rhodopsin in the two strains reveals that little light backscattered from the sclera can enter the ROS. The bleaching-induced increases in reflectance at the IS/OS junctions and OS tips resemble results previously reported in human cones, but are ascribed to rods due to their 30/1 predominance over cones in mice and to the relatively minor amount of cone M-opsin in the regions scanned. PMID:27403994

Admittance Scanning for Whole Column Detection.

Science.gov (United States)

Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi

2017-07-05

Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

A fully-automated computer-assisted method of CT brain scan analysis for the measurement of cerebrospinal fluid spaces and brain absorption density

International Nuclear Information System (INIS)

Baldy, R.E.; Brindley, G.S.; Jacobson, R.R.; Reveley, M.A.; Lishman, W.A.; Ewusi-Mensah, I.; Turner, S.W.

1986-01-01

Computer-assisted methods of CT brain scan analysis offer considerable advantages over visual inspection, particularly in research; and several semi-automated methods are currently available. A new computer-assisted program is presented which provides fully automated processing of CT brain scans, depending on ''anatomical knowledge'' of where cerebrospinal fluid (CSF)-containing spaces are likely to lie. After identifying these regions of interest quantitative estimates are then provided of CSF content in each slice in cisterns, ventricles, Sylvian fissure and interhemispheric fissure. Separate measures are also provided of mean brain density in each slice. These estimates can be summated to provide total ventricular and total brain volumes. The program shows a high correlation with measures derived from mechanical planimetry and visual grading procedures, also when tested against a phantom brain of known ventricular volume. The advantages and limitations of the present program are discussed. (orig.)

Measurements of nonlinear optical properties of PVDF/ZnO using Z-scan technique

Energy Technology Data Exchange (ETDEWEB)

Shanshool, Haider Mohammed, E-mail: haidshan62@gmail.com [Ministry of Science and Technology, Baghdad (Iraq); Yahaya, Muhammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia); Yunus, Wan Mahmood Mat [Department of Physics, Faculty of Science, University Putra Malaysia, Serdang (Malaysia); Abdullah, Ibtisam Yahya [Department of Physics, College of Science, University of Mosul, Mosul (Iraq)

2015-10-15

The nonlinear optical properties of ZnO nanoparticles dispersed in poly (vinylidene fluoride) (PVDF) polymer are investigated. PVDF/ZnO nanocomposites were prepared by mixing different concentrations of ZnO nanoparticles, as the filler, with PVDF, as the polymer matrix, using casting method. Acetone was used as a solvent for the polymer. FTIR spectra of the samples were analyzed thus confirming the formation of α and β phases. The absorbance spectra of the samples were obtained, thereby showing high absorption in the UV region. The linear absorption coefficient was calculated. The single-beam Z-scan technique was used to measure the nonlinear refractive index and the nonlinear absorption coefficient of the PVDF/ZnO nanocomposite samples. We observed that the nonlinear refractive index is in the order of 10{sup -13} cm{sup 2}/W with the negative sign, whereas the nonlinear absorption coefficient is in the order of 10{sup -8} cm/W. (author)

Computed Tomography Scanning and Geophysical Measurements of Core from the Coldstream 1MH Well

Energy Technology Data Exchange (ETDEWEB)

Crandall, Dustin M.; Brown, Sarah; Moore, Johnathan E.; Mackey, Paige E.; Paronish, Thomas J.

2018-03-05

The computed tomography (CT) facilities and the Multi-Sensor Core Logger (MSCL) at the National Energy Technology Laboratory (NETL) Morgantown, West Virginia site were used to characterize core of the Marcellus Shale from a vertical well, the Coldstream 1MH Well in Clearfield County, PA. The core is comprised primarily of the Marcellus Shale from a depth of 7,002 to 7,176 ft.

The primary impetus of this work is a collaboration between West Virginia University (WVU) and NETL to characterize core from multiple wells to better understand the structure and variation of the Marcellus and Utica shale formations. As part of this effort, bulk scans of core were obtained from the Coldstream 1MH well, provided by the Energy Corporation of America (now Greylock Energy). This report, and the associated scans, provide detailed datasets not typically available from unconventional shales for analysis. The resultant datasets are presented in this report, and can be accessed from NETL's Energy Data eXchange (EDX) online system using the following link: https://edx.netl.doe.gov/dataset/coldstream-1mh-well.

All equipment and techniques used were non-destructive, enabling future examinations to be performed on these cores. None of the equipment used was suitable for direct visualization of the shale pore space, although fractures and discontinuities were detectable with the methods tested. Low resolution CT imagery with the NETL medical CT scanner was performed on the entire core. Qualitative analysis of the medical CT images, coupled with x-ray fluorescence (XRF), P-wave, and magnetic susceptibility measurements from the MSCL were useful in identifying zones of interest for more detailed analysis as well as fractured zones. En echelon fractures were observed at 7,100 ft and were CT scanned using NETL’s industrial CT scanner at higher resolution. The ability to quickly identify key areas for more detailed study with higher resolution will save time and

Scanning For Hotspots In Lamp Filaments

Science.gov (United States)

Powers, Charles E.; Van Sant, Tim; Leidecker, Henning

1993-01-01

Scanning photometer designed for use in investigation of failures of incandescent lamp filaments. Maps brightness as function of position along each filament to identify bright (hot) spots, occurring at notches and signifying incipient breaks or rewelds. Also used to measure nonuniformity in outputs of such linear devices as light-emitting diodes, and to measure diffraction patterns of lenses.

A comparative study of linear measurement of the brain and three-dimensional measurement of brain volume using CT scans

International Nuclear Information System (INIS)

Hamano, K.; Iwasaki, N.; Takeya, T.; Takita, H.

1993-01-01

Parameters of linear measurement were compared with actual brain volume to assess the significance of linear measurements as indices of atrophy in 31 neurologically normal children and 22 neurologically abnormal children. Brain volume was established by means of an image-analyzing system using contiguous CT scans. The parameters or indices estimated were: (1) the maximum transverse width of both hemispheres, (2) the maximum longitudinal length of both hemispheres, (3) the maximum frontal subarachnoid space, (4) the maximum width of the interhemispheric fissure, (5) the maximum width of the Sylvian fissure, (6) Evans' ratio, (7) the maximum width of the third ventricle, (8) the cella media index, (9) the maximum width of the fourth ventricle. In neurologically normal children, the maximum transverse width of both hemispheres, the maximum longitudinal length of both hemispheres, the maximum width of the interhemispheric fissure and the maximum width of the Sylvian fissure correlated significantly with the combined volume (CV) of both hemipheres and basal ganglia. In particular, the maximum transverse width of both hemispheres and the maximum longitudinal length of both hemispheres had a high correlation. In neurologically abnormal children the maximum transverse width of both hemispheres and the maximum width of the interhemispheric fissure were significantly correlated with the CV of both hemispheres and basal ganglia. (orig.)

Scavenging processes in high speed two-stroke engines studied with laser diagnostics

Energy Technology Data Exchange (ETDEWEB)

Ekenberg, M.

1998-12-31

The major problem with the carburetted two-stroke engine is the short-circuiting of fuel that occurs during the scavenging phase. This leads to large emissions of unburned hydrocarbons. The object of this thesis has been to map the flow behaviour in the cylinder during the scavenging phase, and to detect differences between different cylinder designs. The measurement techniques used has been Laser Doppler Velocimetry (LDV), Laser Induced Fluorescence (LIF) and Laser Sheet Droplet Illumination (LSDI). Of these measurement methods, LDV and LSDI has been used inside the cylinder. LIF was used outside the exhaust port. All measurements were performed in engines running at their rated speeds, 9000 rpm for three of the designs and 5800 rpm for one design. All engines were run at full load with combustion. The LDV measurements inside the cylinder show that cylinders with cup handle transfer channels have a flow pattern inside the cylinder that gives less short-circuiting, and hence less emissions of hydrocarbons, than the cylinder with open transfer channels has. The LIF measurements outside the exhaust port show that the HC emissions that are caused by short-circuiting comes earlier in the scavenging phase for the cylinder with open transfer channels than is the case for the cylinders with cup handle transfer channels. The LSDI measurements in the cylinder give the transfer channel flow angle, for the cylinders with cup handle transfer channels. For the cylinder with open transfer channels, the results are not as useful; fuel droplet vaporization close to the exhaust port ruins the results 35 refs, 43 figs

Scanning Color Laser Microscope

Science.gov (United States)

Awamura, D.; Ode, T.; Yonezawa, M.

1988-01-01

A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system

International Nuclear Information System (INIS)

Speidel, Michael A.; Wilfley, Brian P.; Heanue, Joseph A.; Betts, Timothy D.; Van Lysel, Michael S.

2001-01-01

Vessel contrast was measured in the fluoroscopic images produced by a scanning-beam digital x-ray (SBDX) system and an image intensifier/television (II/TV) based system. The SBDX system electronically scans a series of pencil x-ray beams across the patient, each of which is directed at a distant small-area detector array. The reduction in detected scatter achieved with this geometry was expected to provide an increase in image contrast. Vessel contrast was evaluated from images of a phantom containing iodinated tubes. The vessels were inserted into an acrylic stack to provide a patient-mimicking scattering medium. Vessel diameter ranged from 0.3 to 3.1 mm. Images were acquired at 100 kVp with the SBDX and II/TV systems and averaged to reduce x-ray noise. The II/TV system was operated in the 6-in. image intensifier mode with an anti-scatter grid. The increase in contrast in the SBDX images, expressed as a ratio of the measured SBDX and II/TV contrasts, ranged from 1.63 to 1.79 for individual vessels. This agreed well with a prediction of the contrast improvement ratio for this experiment, based on measurements of the scatter fraction, object-plane line spread functions, and consideration of the source spectrum and detector absorption properties. The predicted contrast improvement ratio for SBDX relative to II/TV images was 1.62 to 1.77

Measurement of polarization dependence of two-photon absorption coefficient in InP using extended Z-scan technique for thick materials

Science.gov (United States)

Oishi, Masaki; Shinozaki, Tomohisa; Hara, Hikaru; Yamamoto, Kazunuki; Matsusue, Toshio; Bando, Hiroyuki

2018-03-01

The two-photon absorption coefficient β in InP has been measured in the wavelength range of 1640 to 1800 nm by the Z-scan technique in relatively thick materials. The values of β have been evaluated from the fit to the equation including the spatial and temporal profiles of the focused Gaussian beam. The polarization dependence of β has also been measured. The dependence has been expressed very well by the expression of β with the imaginary part of the third-order nonlinear susceptibility tensor χ(3).

Fast IMRT with narrow high energy scanned photon beams

Energy Technology Data Exchange (ETDEWEB)

Andreassen, Bjoern; Straaring t, Sara Janek; Holmberg, Rickard; Naefstadius, Peder; Brahme, Anders [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, P.O. Box 260, SE-171 76 Stockholm (Sweden); Department of Hospital Physics, Karolinska University Hospital, SE-171 76 Stockholm (Sweden); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, P.O. Box 260, SE-171 76 Stockholm, Sweden and Department of Hospital Physics, Karolinska University Hospital, SE-171 76 Stockholm (Sweden)

2011-08-15

Purpose: Since the first publications on intensity modulated radiation therapy (IMRT) in the early 1980s almost all efforts have been focused on fairly time consuming dynamic or segmental multileaf collimation. With narrow fast scanned photon beams, the flexibility and accuracy in beam shaping increases, not least in combination with fast penumbra trimming multileaf collimators. Previously, experiments have been performed with full range targets, generating a broad bremsstrahlung beam, in combination with multileaf collimators or material compensators. In the present publication, the first measurements with fast narrow high energy (50 MV) scanned photon beams are presented indicating an interesting performance increase even though some of the hardware used were suboptimal. Methods: Inverse therapy planning was used to calculate optimal scanning patterns to generate dose distributions with interesting properties for fast IMRT. To fully utilize the dose distributional advantages with scanned beams, it is necessary to use narrow high energy beams from a thin bremsstrahlung target and a powerful purging magnet capable of deflecting the transmitted electron beam away from the generated photons onto a dedicated electron collector. During the present measurements the scanning system, purging magnet, and electron collimator in the treatment head of the MM50 racetrack accelerator was used with 3-6 mm thick bremsstrahlung targets of beryllium. The dose distributions were measured with diodes in water and with EDR2 film in PMMA. Monte Carlo simulations with geant4 were used to study the influence of the electrons transmitted through the target on the photon pencil beam kernel. Results: The full width at half-maximum (FWHM) of the scanned photon beam was 34 mm measured at isocenter, below 9.5 cm of water, 1 m from the 3 mm Be bremsstrahlung target. To generate a homogeneous dose distribution in a 10 x 10 cm{sup 2} field, the authors used a spot matrix of 100 equal intensity

Line-scanning tomographic optical microscope with isotropic transfer function

International Nuclear Information System (INIS)

Gajdátsy, Gábor; Dudás, László; Erdélyi, Miklós; Szabó, Gábor

2010-01-01

An imaging method and optical system, referred to as a line-scanning tomographic optical microscope (LSTOM) using a combination of line-scanning technique and CT reconstruction principle, is proposed and studied theoretically and experimentally. In our implementation a narrow focus line is scanned over the sample and the reflected light is measured in a confocal arrangement. One such scan is equivalent to a transverse projection in tomography. Repeating the scanning procedure in several directions, a number of transverse projections are recorded from which the image can be obtained using conventional CT reconstruction algorithms. The resolution of the image is independent of the spatial dimensions and structure of the applied detector; furthermore, the transfer function of the system is isotropic. The imaging performance of the implemented confocal LSTOM was compared with a point-scanning confocal microscope, based on recorded images. These images demonstrate that the resolution of the confocal LSTOM exceeds (by 15%) the resolution limit of a point-scanning confocal microscope

Multichannel scanning spectrophotometer

International Nuclear Information System (INIS)

Lagutin, A.F.

1979-01-01

A spectrophotometer designed in the Crimea astrophysical observatory is described. The spectrophotometer is intended for the installation at the telescope to measure energy distribution in the star spectra in the 3100-8550 A range. The device is made according to the scheme with a fixed diffraction lattice. The choice of the optical kinematic scheme is explained. The main design elements are shown. Some singularities of the scanning drive kinematics are considered. The device performance is given

Improving quality of laser scanning data acquisition through calibrated amplitude and pulse deviation measurement

Science.gov (United States)

Pfennigbauer, Martin; Ullrich, Andreas

2010-04-01

Newest developments in laser scanner technologies put surveyors in the position to comply with the ever increasing demand of high-speed, high-accuracy, and highly reliable data acquisition from terrestrial, mobile, and airborne platforms. Echo digitization in pulsed time-of-flight laser ranging has demonstrated its superior performance in the field of bathymetry and airborne laser scanning for more than a decade, however at the cost of somewhat time consuming off line post processing. State-of-the-art online waveform processing as implemented in RIEGL's V-Line not only saves users post-processing time to obtain true 3D point clouds, it also adds the assets of calibrated amplitude and reflectance measurement for data classification and pulse deviation determination for effective and reliable data validation. We present results from data acquisitions in different complex target situations.

Lens thickness assessment: anterior segment optical coherence tomography versus A-scan ultrasonography

Directory of Open Access Journals (Sweden)

Nikoo Hamzeh

2015-12-01

Full Text Available AIM: To assess lens thickness measurements with anterior segment-optical coherence tomography (AS-OCT in comparison with A-scan ultrasonography (A-scan US. METHODS: There were 218 adult subjects (218 eyes aged 59.2±9.2y enrolled in this prospective cross-sectional study. Forty-three eyes had open angles and 175 eyes had narrow angles. Routine ophthalmic exam was performed and nuclear opacity was graded using the Lens Opacities Classification System III (LOCS III. Lens thickness was measured by AS-OCT (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA. The highest quality image was selected for each eye and lens thickness was calculated using ImageJ software. Lens thickness was also measured by A-scan US. RESULTS: Interclass correlations showed a value of 99.7% for intra-visit measurements and 95.3% for inter-visit measurements. The mean lens thickness measured by AS-OCT was not significantly different from that of A-scan US (4.861±0.404 vs 4.866±0.351 mm, P=0.74. Lens thickness values obtained from the two instruments were highly correlated overall (Pearson correlation coefficient=0.81, P<0.001, and in all LOCS III specific subgroups except in grade 5 of nuclear opacity. Bland-Altman analysis revealed a 95% limit of agreement from -0.45 to 0.46 mm. Lens thickness difference between the two instruments became smaller as the lens thickness increased and AS-OCT yielded smaller values than A-scan US in thicker lens (β=-0.29, P<0.001 CONCLUSION: AS-OCT-derived lens thickness measurement is valid and comparable to the results obtained by A-scan US. It can be used as a reliable noncontact method for measuring lens thickness in adults with or without significant cataract.

SU-E-T-542: Measurement of Internal Neutrons for Uniform Scanning Proton Beams

Energy Technology Data Exchange (ETDEWEB)

Islam, M; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Zheng, Y; Rana, S [Procure Proton Therapy Center, Oklahoma City, OK (United States); Collums, T [University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Monsoon, J; Benton, E [Oklahoma State University, Stillwater, OK (United States)

2015-06-15

Purpose: In proton radiotherapy, the production of neutrons is a wellknown problem since neutron exposure can lead to increased risk of secondary cancers later in the patient’s lifetime. The assessment of neutron exposure is, therefore, important for the overall quality of proton radiotherapy. This study investigates the secondary neutrons created inside the patient from uniform scanning proton beams. Methods: Dose equivalent due to secondary neutrons was measured outside the primary field as a function of distance from beam isocenter at three different angles, 45, 90 and 135 degree, relative to beam axis. Plastic track nuclear detector (CR-39 PNTD) was used for the measurement of neutron dose. Two experimental configurations, in-air and cylindrical-phantom, were designed. In a cylindrical-phantom configuration, a cylindrical phantom of 5.5 cm diameter and 35 cm long was placed along the beam direction and in an in-air configuration, no phantom was used. All the detectors were placed at nearly identical locations in both configurations. Three proton beams of range 5 cm, 18 cm, and 32 cm with 4 cm modulation width and a 5 cm diameter aperture were used. The contribution from internal neutrons was estimated from the differences in measured dose equivalent between in-air and cylindrical-phantom configurations at respective locations. Results: The measured ratio of neutron dose equivalent to the primary proton dose (H/D) dropped off with distance and ranged from 27 to 0.3 mSv/Gy. The contribution of internal neutrons near the treatment field edge was found to be up to 64 % of the total neutron exposure. As the distance from the field edge became larger, the external neutrons from the nozzle appear to dominate and the internal neutrons became less prominent. Conclusion: This study suggests that the contribution of internal neutrons could be significant to the total neutron dose equivalent.

Efficient scanning of thick lead vessels

International Nuclear Information System (INIS)

Raghunath, V.M.; Bhatnagar, P.K.; Meenakshisundaram, V.

1978-01-01

Lead containers fabricated for transport of radioactive materials need to be evaluated for their shielding integrity. The common method of locating a strong gamma source inside the vessel and scanning the external surface by conventional detectors suffers from high radiation dose and low sensitivity. A new method has been proposed and tried. It is found to be more efficient. In the new method, 60 Co source is loaded at the centre of the lead vessel and the outer surface is scanned by NaI(Tl) detector. The transmitted virgin flux is scanned under the 60 Co channel in a single channel analyser. An area of 25 cm 2 is scanned for 10 to 20 seconds each time. The source strength required is considerably reduced by a factor of 10 or more as compared to the common method and external dose rates do not exceed 50 mR/h (130 nC. kg -1 h -1 ) on the vessel surface. The advantages are improved sensitivity, no interference from scattered radiation and assurance in repeatability of measurements. (M.G.B.)

Stability of some Cactaceae proteins based on fluorescence, circular dichroism, and differential scanning calorimetry measurements.

Science.gov (United States)

Gorinstein, S; Zemser, M; Vargas-Albores, F; Ochoa, J L; Paredes-Lopez, O; Scheler, C; Aksu, S; Salnikow, J

1999-02-01

Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.

Some practical aspects of dual-energy CT scanning

International Nuclear Information System (INIS)

Dunscombe, P.B.; Katz, D.E.; Stacey, A.J.

1984-01-01

Using the dual-energy scanning method developed by Brooks (1977), and making slow x-ray scans at 100 kVp, 35 mA and 140 kVp, 20 mA, measurements were made of electron density and effective atomic number in the lumbar spines of 36 patients aged from 22 to 87 years, and not known to be suffering from conditions which result in osteoporosis or osteomalacia. The authors discuss in detail the sources of experimental error which contributed to the large measured spread of normal values of electron density and effective atomic number. (U.K.)

SU-F-I-27: Measurement of SAR and Temperature Elevation During MRI Scans

Energy Technology Data Exchange (ETDEWEB)

Seo, Y [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2016-06-15

Purpose: The poor reliability and repeatability of the manufacturer-reported SAR values on clinical MRI systems have been acknowledged. The purpose of this study is to not only measure SAR values, but also RF-induced temperature elevation at 1.5 and 3T MRI systems. Methods: SAR measurement experiment was performed at 1.5 and 3T. Three MRI RF sequences (T1w TSE, T1w inversion recovery, and T2w TSE) with imaging parameters were selected. A hydroxyl-ethylcelluose (HEC) gelled saline phantom mimicking human body tissue was made. Human torso phantom were constructed, based on Korean adult standard anthropometric reference data (Fig.1). FDTD method was utilized to calculate the SAR distribution using Sim4Life software. Based on the results of the simulation, 4 electrical field (E-field) sensors were located inside the phantom. 55 Fiber Bragg Grating (FBG) temperature sensors (27 sensors in upper and lower cover lids, and one sensor located in the center as a reference) were located inside the phantom to measure temperature change during MRI scan (Fig.2). Results: Simulation shows that SAR value is 0.4 W/kg in the periphery and 0.001 W/kg in the center (Fig.2). One 1.5T and one of two 3T MRI systems represent that the measured SAR values were lower than MRI scanner-reported SAR values. However, the other 3T MRI scanner shows that the averaged SAR values measured by probe 2, 3, and 4 are 6.83, 7.59, and 6.01 W/kg, compared to MRI scanner-reported whole body SAR value (<1.5 W/kg) for T2w TSE (Table 1). The temperature elevation measured by FBG sensors is 5.2°C in the lateral shoulder, 5.1°C in the underarm, 4.7°C in the anterior axilla, 4.8°C in the posterior axilla, and 4.8°C in the lateral waist for T2w TSE (Fig.3). Conclusion: It is essential to assess the safety of MRI system for patient by measuring accurate SAR deposited in the body during clinical MRI.

Microstructural and Z-scan measurement of silver nanoparticles

International Nuclear Information System (INIS)

Sivakami, R.; Dhanuskodi, S.

2015-01-01

Graphical abstract: - Highlights: • Novel Ag nanoparticles were prepared by hydrothermal method. • The modified forms of W-H analysis of Ag nanoparticles are reported first time. • Nonlinear optical (NLO) properties of Ag nanoflowers are reported and high nonlinearity was obtained. - Abstract: Silver nanoflowers were synthesized by the hydrothermal route. Formation of Ag nanoparticles is confirmed from the UV–vis spectrum where the surface plasmon absorption maxima are observed at 415–454 nm. FE-SEM and TEM images revealed the formation of silver nanoflowers and the flower-like silver nanostructures are estimated using transmission electron microscopy. XRD confirms that the synthesized silver is highly crystalline with face centered cubic structure. The X-ray line broadening is studied by the modified forms of Williamson–Hall analysis. The Z-scan results reveal that the flower-like silver nanostructures exhibit the nonlinear susceptilibility as 1.14 × 10 −5 esu

Inhalation scan using sup(81m)Kr-gas

International Nuclear Information System (INIS)

Kobayashi, Hidetoshi; Sasaki, Tsuneo; Senda, Kohei; Ohara, Ken; Kaii, Osamu

1979-01-01

Inhalation scan using sup(81m) Kr-gas was performed in the various pulmonary diseases, in order to examine the ventilatory function of the lung after the measurement of ratio of expiratory ratio in the normal and diseased lung field. Inhalation scan is applied to the various pulmonary diseases such as lung cancer, radiation pulmonary fibrosis and chronic obstructive pulmonary disease. In cases of lung cancer, there is disturbance of respiratory function at the site of lesion when compared to the remainder of the normal lung fields. In cases of chronic obstructive pulmonary disease, the inhalation scan is performed at three states such as pre-, in- and post-attack of the disease. During the asthma attack the respiratory function is disturbed considerably when compared to the pre- and post-attack states. In each pulmonary disease, the ratio of expiratory ratio is measured from the histogram and pulmonary function is evaluated. (author)