scholarly journals Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1709 ◽  
Author(s):  
Curto ◽  
Aklan ◽  
Mulder ◽  
Mils ◽  
Schmidt ◽  
...  
Keyword(s):  
Hybrid Systems ◽  
Dose Effect ◽  
Institutional Evaluation ◽  
Anthropomorphic Phantoms ◽  
Contrast Magnetic Resonance ◽  
Scatter Plots ◽  
Conformal Heating ◽  
Probe Measurements ◽  
Eccentric Target ◽  
Good Agreement

Clinical outcome of hyperthermia depends on the achieved target temperature, therefore target conformal heating is essential. Currently, invasive temperature probe measurements are the gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast, magnetic resonance thermometry (MRT) provides unique capabilities to non-invasively measure the 3D-temperature. This study investigates MRT accuracy for MR-hyperthermia hybrid systems located at five European institutions while heating a centric or eccentric target in anthropomorphic phantoms with pelvic and spine structures. Scatter plots, root mean square error (RMSE) and Bland–Altman analysis were used to quantify accuracy of MRT compared to high resistance thermistor probe measurements. For all institutions, a linear relation between MRT and thermistor probes measurements was found with R2 (mean ± standard deviation) of 0.97 ± 0.03 and 0.97 ± 0.02, respectively for centric and eccentric heating targets. The RMSE was found to be 0.52 ± 0.31 °C and 0.30 ± 0.20 °C, respectively. The Bland-Altman evaluation showed a mean difference of 0.46 ± 0.20 °C and 0.13 ± 0.08 °C, respectively. This first multi-institutional evaluation of MR-hyperthermia hybrid systems indicates comparable device performance and good agreement between MRT and thermistor probes measurements. This forms the basis to standardize treatments in multi-institution studies of MR-guided hyperthermia and to elucidate thermal dose-effect relations.

scholarly journals Development of a Dynamic Cathode Ejector Model for Solid Oxide Fuel Cell-Gas Turbine Hybrid Systems

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
James D. Maclay ◽  
Jacob Brouwer ◽  
G. Scott Samuelsen
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Solid Oxide ◽  
Theoretical Development ◽  
Oxide Fuel ◽  
Simulink Model ◽  
Fuel Cell Cathode ◽  
Good Agreement

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems are attractive for future power generation with ultra-low criteria pollutant and greenhouse gas emissions. One of the challenges for SOFC-GT systems is to sufficiently pre-heat incoming air before it enters the fuel cell cathode. An ejector for cathode exhaust recirculation has the benefits of reliability, low maintenance, and cost compared to either recuperators or cathode recirculation blowers, which may be also be used for air pre-heating. In this study, a dynamic Simulink model of an ejector for cathode exhaust recirculation to pre-heat incoming fuel cell air has been developed. The ejector is to be utilized within a 100 MW SOFC-GT dynamic model operating on coal syngas. A thorough theoretical development is presented. Results for the ejector were found to be in good agreement with those reported in literature.

An experimental and numerical investigation of under-expanded turbulent jets

2004 ◽  
Vol 108 (1081) ◽  
pp. 145-152 ◽  
Author(s):  
A. J. Saddington ◽  
N. J. Lawson ◽  
K. Knowles
Keyword(s):  
Turbulence Model ◽  
Nozzle Exit ◽  
Experimental Studies ◽  
Independent Solution ◽  
Turbulent Jets ◽  
Cell Length ◽  
Cfd Model ◽  
Shock Cell ◽  
Probe Measurements ◽  
Good Agreement

AbstractThe work described here concentrates on under-expanded, axisym-metric turbulent jets issuing into quiescent conditions. Under-expanded turbulent jets are applicable to most aircraft propulsion applications that use convergent nozzles. Experimental studies used laser doppler velocimetry (LDV) and pitot probe measurements along the jet centreline. These measurements were made for two nozzle pressure ratios (2·5 and 4·0) and at various streamwise positions up to 10 nozzle diameters downstream of the nozzle exit plane. A computational fluid dynamics (CFD) model was developed using the Fluent code and utilised the RNG K-ε two-equation turbulence model. A mesh resolution of approximately one hundredth of nozzle exit diameter was found to be sufficient to establish a mesh independent solution.Comparison of the jet centreline axial velocity (LDV data) and pressure ratio (pitot probe data) showed good agreement with the CFD model. The correct number of shock cells had been predicted and the shock strength agreed well between the experiments and numerical model. The CFD model was, however, found to over-predict the shock cell length resulting in a longer supersonic core. There was some evidence, based on analysis of the LDV measurements that indicates the presence of swirl and jet unsteadiness, which could contribute to a shortening of the shock cell length. These effects were not modelled in the CFD. Correlation between the LDV and pitot probe measurements was generally good, however, there was some evidence that probe interference may have caused the premature decay of the jet. Overall, this work has indicated the good agreement between a CFD simulation using the RNG k-ε turbulence model and experimental data when applied to the prediction of the flowfield generated by under-expanded turbulent jets. The suitability of the LDV technique to jet flows with velocities up to 500ms-1has also been demonstrated.

scholarly journals Flexibility of noncompetitive avidin-biotin immunoassay: immunoassay of lutropin applied to different signal detection systems

1990 ◽  
Vol 36 (11) ◽  
pp. 1897-1901 ◽  
Author(s):  
P Vilja
Keyword(s):  
Signal Detection ◽  
Linear Relation ◽  
Detection System ◽  
Correlation Coefficients ◽  
Urine Samples ◽  
Time Resolved ◽  
Detection Systems ◽  
Enzyme Substrate ◽  
Scatter Plots ◽  
Good Agreement

Abstract I adapted the noncompetitive avidin-biotin immunoassay (NABA) of lutropin (LH) for use with radiometric, fluorometric, time-resolved fluorometric, and luminometric detection systems by changing the enzyme substrate or conjugating avidin with different labels. The corresponding methods were used to determine LH in 40 urine samples, and the results were compared with those obtained by an immunoenzymometric assay (IEMA), also based on the NABA principle. Scatter plots of the results showed a linear relation with high correlation coefficients (r = 0.972-0.983), and bias plots showed good agreement between the four comparison methods and the IEMA. The results indicate that the effectiveness of the NABA of LH is independent of the signal detection system. This means good flexibility for the user in choice of instrument and signal detection system.

Detection and Modeling of the Core-Annulus Transition in Industrial and Pilot Plant Risers

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Lauren Briens ◽  
Cedric Briens ◽  
David Nevicato ◽  
Jean René Bernard
Keyword(s):  
Pilot Plant ◽  
Signal Analysis ◽  
Optical Probe ◽  
Transition Analysis ◽  
The Core ◽  
Model Predictions ◽  
Vertical Pneumatic Transport ◽  
Probe Measurements ◽  
Good Agreement

The core-annulus structure is essential to the modeling and optimization of riser reactors such as used in Fluid Catalytic Cracking. This paper presents results of measurements taken with various probes in a pilot plant and in an industrial riser. The instantaneous probe signals were analyzed with sophisticated signal analysis methods based on the detection of cycles and the determination of the correlation dimension.In a pilot plant riser, a core-annulus structure was identified with optical and momentum probe measurements. Cycle analysis of the optical probe measurements showed that the annulus was unstable: its thickness fluctuated with an average cycle time of 0.3 s. There were waves at the core-annulus boundary. In an industrial riser, a similar core-annulus structure could be identified with temperature and momentum probe measurements. Local temperature measurements are much easier to perform in an industrial riser than momentum probe measurements but can provide, with cycle analysis, the location of the core-annulus transition. Analysis of the momentum probe and temperature signals showed that the thickness of the wavy transition layer between core and annulus was about the same in the pilot plant and the industrial riser, meaning that the relative range of fluctuations in annulus thickness was much smaller in the larger industrial riser.A model was developed to predict the time-averaged transition between core and annulus. This model, which had been successfully used to predict the annulus thickness in dilute-phase vertical pneumatic transport lines, assumes that the annulus thickness is such that the riser pressure drop is minimized. Measurements and model predictions were in good agreement.

An experimental and numerical investigation of under-expanded turbulent jets

2004 ◽  
Vol 108 (1081) ◽  
pp. 145-152 ◽  
Author(s):  
A. J. Saddington ◽  
N. J. Lawson ◽  
K. Knowles
Keyword(s):  
Turbulence Model ◽  
Nozzle Exit ◽  
Experimental Studies ◽  
Independent Solution ◽  
Turbulent Jets ◽  
Cell Length ◽  
Cfd Model ◽  
Shock Cell ◽  
Probe Measurements ◽  
Good Agreement

AbstractThe work described here concentrates on under-expanded, axisym-metric turbulent jets issuing into quiescent conditions. Under-expanded turbulent jets are applicable to most aircraft propulsion applications that use convergent nozzles. Experimental studies used laser doppler velocimetry (LDV) and pitot probe measurements along the jet centreline. These measurements were made for two nozzle pressure ratios (2·5 and 4·0) and at various streamwise positions up to 10 nozzle diameters downstream of the nozzle exit plane. A computational fluid dynamics (CFD) model was developed using the Fluent code and utilised the RNG K-ε two-equation turbulence model. A mesh resolution of approximately one hundredth of nozzle exit diameter was found to be sufficient to establish a mesh independent solution.Comparison of the jet centreline axial velocity (LDV data) and pressure ratio (pitot probe data) showed good agreement with the CFD model. The correct number of shock cells had been predicted and the shock strength agreed well between the experiments and numerical model. The CFD model was, however, found to over-predict the shock cell length resulting in a longer supersonic core. There was some evidence, based on analysis of the LDV measurements that indicates the presence of swirl and jet unsteadiness, which could contribute to a shortening of the shock cell length. These effects were not modelled in the CFD. Correlation between the LDV and pitot probe measurements was generally good, however, there was some evidence that probe interference may have caused the premature decay of the jet. Overall, this work has indicated the good agreement between a CFD simulation using the RNG k-ε turbulence model and experimental data when applied to the prediction of the flowfield generated by under-expanded turbulent jets. The suitability of the LDV technique to jet flows with velocities up to 500ms-1has also been demonstrated.

Some electrically driven flows in magnetohydrodynamics Part 3. The asymptotic theory for flow between circular electrodes

1969 ◽  
Vol 38 (2) ◽  
pp. 225-242 ◽  
Author(s):  
J. C. R. Hunt ◽  
K. Stewartson
Keyword(s):  
Electrical Potential ◽  
Mhd Flow ◽  
Conducting Liquid ◽  
Electrically Conducting ◽  
Direct Measurements ◽  
Hot Film ◽  
Theoretical Results ◽  
A Current ◽  
Probe Measurements ◽  
Good Agreement

In this, the third, part we present a complete asymptotic analysis of the distribution of velocity and electric potential in an electrically conducting liquid between two circular electrodes of finite diameter, 2b, when a current is passed between them. The electrodes are set opposite to each other in insulating planes, a distance 2aapart, and a magnetic field is applied perpendicular to these planes.The asymptotic solution is obtained under the restriction that the Hartmann numberMsatisfies both the conditionsM[Gt ] 1 andM½l[Gt ] 1, wherel=b/a. It enables us to calculate the distribution of velocity and electrical potential throughout the flow field, and provides an expansion for the resistanceRbetween the electrodes in descending powers ofM½l, which is correct provided terms of orderM−1and (lM½)−3are neglected. Comparison of the theoretical results with experiment shows good agreement in the measurements ofRand in the direct probe measurements of electrical potential within the fluid. This is one of the first experiments in which direct probe measurements of an MHD flow, as well as external measurements, have provided such a satisfactory confirmation of the theory. Direct measurements of the velocity, by means of a Pitot tube as in part 2, or by means of a hot-film anemometer undertaken by Malcolm (1968), agree less well with the theory.

Retrieval of tropospheric BrO columns from TROPOMI and their validation using MAX-DOAS measurements in Ny-Ålesund

2021 ◽  
Author(s):  
Sora Seo ◽  
Andreas Richter ◽  
Anne-M. Blechschmidt ◽  
Ilias Bougoudis ◽  
Folkard Wittrock ◽  
...  
Keyword(s):  
Satellite Data ◽  
Atmospheric Chemistry ◽  
Multiple Linear Regression Model ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Small Scale ◽  
Satellite Measurements ◽  
Scatter Plots ◽  
Total Column ◽  
Good Agreement

<p>Bromine compounds play an important role in atmospheric chemistry with respect to ozone chemistry and the resulting oxidation capacity. Large amounts of reactive bromine can be released by an autocatalytic heterogeneous mechanism called “bromine explosion”, and plumes of enhanced bromine monoxide (BrO) have been observed over polar sea ice regions by satellite measurements in spring. These enhancements of BrO columns result from increases in stratospheric or tropospheric bromine columns or both. As nadir-viewing UV-visible spectrometers have limited vertical resolution, it is not straight-forward to separate total BrO columns into tropospheric and stratospheric partial columns using satellite data.</p><p>In this study, an algorithm for tropospheric BrO retrieval from satellite measurements including TROPOMI, which provides much improved spatial resolution, was developed. The retrieval algorithm is based on the Differential Optical Absorption Spectroscopy (DOAS) technique and three different stratospheric correction methods were tested based on: output from a 3D atmospheric chemistry model, a climatology of stratospheric BrO profiles, and an empirical multiple linear regression model to separate the tropospheric partial column from the total column.</p><p>Retrieved tropospheric BrO columns from satellite measurements were compared with ground-based MAX-DOAS BrO observations at the NDACC station in Ny-Ålesund. The comparisons between ground-based and satellite measurements of tropospheric BrO show good agreement in both time-series and scatter plots, demonstrating the satellite retrieval algorithm is valid and applicable to study bromine release in the tropospheric layer. In particular, TROPOMI shows improved validation results for short distance collection compared to previous satellite data, which suggests the applicability of high-resolution satellite data on small-scale bromine explosion events observed during the MOSAiC campaign.</p>

Gene-expression programming for flip-bucket spillway scour

2012 ◽  
Vol 65 (11) ◽  
pp. 1982-1987 ◽  
Author(s):  
Aytac Guven ◽  
H. Md. Azamathulla
Keyword(s):  
Gene Expression ◽  
Gene Expression Programming ◽  
Statistical Error ◽  
Field Measurements ◽  
Error Measures ◽  
Soft Computing Techniques ◽  
Scatter Plots ◽  
Actual Field ◽  
Better Than ◽  
Good Agreement

During the last two decades, researchers have noticed that the use of soft computing techniques as an alternative to conventional statistical methods based on controlled laboratory or field data, gave significantly better results. Gene-expression programming (GEP), which is an extension to genetic programming (GP), has nowadays attracted the attention of researchers in prediction of hydraulic data. This study presents GEP as an alternative tool in the prediction of scour downstream of a flip-bucket spillway. Actual field measurements were used to develop GEP models. The proposed GEP models are compared with the earlier conventional GP results of others (Azamathulla et al. 2008b; RMSE = 2.347, δ = 0.377, R = 0.842) and those of commonly used regression-based formulae. The predictions of GEP models were observed to be in strictly good agreement with measured ones, and quite a bit better than conventional GP and the regression-based formulae. The results are tabulated in terms of statistical error measures (GEP1; RMSE = 1.596, δ = 0.109, R = 0.917) and illustrated via scatter plots.

Competitive Role of Impurities on the Electrical Activity of as-grown Σ=13, Σ=25 and Deformed Σ=9 Grain boundaries in p-type Silicon Bi-crystals

2012 ◽  
Vol 1474 ◽  
Author(s):  
S. Gaiaschi ◽  
A. El Kouadri Boudjelthia ◽  
G. Regula ◽  
N. Burle ◽  
A. Mesli ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Before And After ◽  
Electron Beam Induced Current ◽  
Gold Diffusion ◽  
P Type ◽  
Czochralski Process ◽  
Probe Measurements ◽  
Good Agreement

ABSTRACTElectrical properties of grain boundaries grown by Czochralski process were studied by microwave phase shift (μW-PS) and electron beam induced current (EBIC), before and after gold diffusion at 700°C. As-grown samples had similar doping levels determined by four-point probe measurements but somewhat different oxygen concentrations, obtained by Fourier transform infrared spectroscopy (FTIR). It is shown that the increase of the grain boundary activity due to Au gathering at this planar defect can be hindered by native impurities (likely oxygen). EBIC and μW-PS techniques gave respectively electron diffusion lengths and lifetime values, both in good agreement. EBIC images on deformed Σ =9 showed that extrinsic dislocations do not activate the grain boundary at 300K.

scholarly journals Swirl Distortion Using Stream Vanes for Boundary Layer Ingestion Research

2019 ◽  
Author(s):  
Julia E. Stephens ◽  
Mark Celestina ◽  
Christopher Hughes
Keyword(s):  
Boundary Layer ◽  
Test Facility ◽  
Interface Plane ◽  
Type I ◽  
Cfd Simulations ◽  
Measurement Plane ◽  
Dense Grid ◽  
The Impact ◽  
Probe Measurements ◽  
Good Agreement

Abstract The swirl distortion of a StreamVane™ was investigated in the NASA Glenn Research Center W8 test facility. The StreamVane™ was designed and generated by Virginia Tech based on CFD simulations and included a center body at the aerodynamic interface plane. The swirl pattern generated by the distortion was evaluated using a dense grid of 5-hole Pitot probe measurements captured using a rotating array of probes. Good agreement was found between the design intent and the results at 38.5 kg/s mass flow. The StreamVane™ swirl results were compared to clean facility flow at 5 inlet mass flows and found to be consistent. Additionally, the axial location of the StreamVane™ relative to the measurement plane was investigated to determine the impact on downstream total pressure loss generated by the vanes. The intent of this work was to assess the viability of using a StreamVane™ to generate a Type I or Type II distortion into a Boundary Layer Ingesting propulsor to assess its aerodynamic performance and aeromechanic response.

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