WorldWideScience

Sample records for dual energy use systems

  1. Design and Simulation of Dual Inverter Based Energy Storage Systems for Wind Energy Systems Using MATLAB/SIMULINK

    Directory of Open Access Journals (Sweden)

    Harika G,

    2014-04-01

    Full Text Available This paper proposes the design and simulation of dual inverter based Energy Storage Systems(ESS for wind energy systems. A dual inverter consists of MAIN inverter which is connected to grid side and an auxiliary inverter for which an energy storage system is interfaced. Typical grid connected wind energy systems includes wind turbine, PMSG, DC-DC converters, three phase dual inverter ,energy storage system and related power electronic devices. The detailed model of design and simulation of dual inverter based Wind energy system starts with wind turbine coupled PMSG which is connected to three phase diode rectifier and Boost converter which in-turn connected to a dual inverter which is used to deliver the wind energy to grid and also to store the energy in energy storage systems during surplus periods. Also Short term power fluctuations are mitigated and harmonics are reduced. Maximum Power point Tracking (MPPT method, Energy storage system interfacing is also studied. The overall system model is designed and simulated by using MATLAB/SIMULINK.

  2. Initial experience of dual-energy lung perfusion CT using a dual-source CT system in children

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Songpa-gu, Seoul (Korea)

    2010-09-15

    Initial experience of dual-source dual-energy (DE) lung perfusion CT in children is described. In addition to traditional identification of pulmonary emboli, the assessment of lung perfusion is technically feasible with dual-source DE CT in children with acceptable radiation dose. This article describes how to perform dual-source DE lung perfusion CT in children, including the optimization of intravenous injection method and CT dose parameters. How to produce weighted-average CT images for the assessment of pulmonary emboli and colour-coded perfusion maps for the assessment of regional lung perfusion is also detailed. Lung perfusion status can then be evaluated on perfusion maps by means of either qualitative or quantitative analysis. Potential advantages and disadvantages of this emerging CT technique compared to lung perfusion scintigraphy and cardiac MRI are discussed. (orig.)

  3. Design and parametric study on energy harvesting from bridge vibration using tuned dual-mass damper systems

    Science.gov (United States)

    Takeya, Kouichi; Sasaki, Eiichi; Kobayashi, Yusuke

    2016-01-01

    A bridge vibration energy harvester has been proposed in this paper using a tuned dual-mass damper system, named hereafter Tuned Mass Generator (TMG). A linear electromagnetic transducer has been applied to harvest and make use of the unused reserve of energy the aforementioned damper system absorbs. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Theoretical analysis results have shown that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations and tuning errors, and the proposed parameter design method for TMG has demonstrated this feature.

  4. Postmortem validation of breast density using dual-energy mammography

    Energy Technology Data Exchange (ETDEWEB)

    Molloi, Sabee, E-mail: symolloi@uci.edu; Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A. [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2014-08-15

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer.

  5. Energy Efficient Hybrid Dual Axis Solar Tracking System

    Directory of Open Access Journals (Sweden)

    Rashid Ahammed Ferdaus

    2014-01-01

    Full Text Available This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanical single axis to a hybrid dual axis. For optimizing the solar tracking mechanism electromechanical systems were evolved through implementation of different evolutional algorithms and methodologies. To present the tracker, a hybrid dual-axis solar tracking system is designed, built, and tested based on both the solar map and light sensor based continuous tracking mechanism. These light sensors also compare the darkness and cloudy and sunny conditions assisting daily tracking. The designed tracker can track sun’s apparent position at different months and seasons; thereby the electrical controlling device requires a real time clock device for guiding the tracking system in seeking solar position for the seasonal motion. So the combination of both of these tracking mechanisms made the designed tracker a hybrid one. The power gain and system power consumption are compared with a static and continuous dual axis solar tracking system. It is found that power gain of hybrid dual axis solar tracking system is almost equal to continuous dual axis solar tracking system, whereas the power saved in system operation by the hybrid tracker is 44.44% compared to the continuous tracking system.

  6. Use of Multibeam and Dual-Beam Sonar Systems to Observe Cavitating Flow Produced by Ferryboats: In a Marine Renewable Energy Perspective

    Directory of Open Access Journals (Sweden)

    Francisco Francisco

    2017-07-01

    Full Text Available With the prospect to deploy hydrokinetic energy converters in areas with heavy boat traffic, a study was conducted to observe and assess the depth range of cavitating flow produced by ferryboats in narrow channels. This study was conducted in the vicinity of Finnhamn Island in Stockholm Archipelago. The objectives of the survey were to assess whether the sonar systems were able to observe and measure the depth of what can be cavitating flow (in a form of convected cloud cavitation produced by one specific type of ferryboats frequently operating in that route, as well as investigate if the cavitating flow within the wake would propagate deep enough to disturb the water column underneath the surface. A multibeam and a dual-beam sonar systems were used as measurement instruments. The hypothesis was that strong and deep wake can disturb the optimal operation of a hydrokinetic energy converter, therefore causing damages to its rotors and hydrofoils. The results showed that both sonar system could detect cavitating flows including its strength, part of the geometrical shape and propagation depth. Moreover, the boat with a propeller thruster produced cavitating flow with an intense core reaching 4 m of depth while lasting approximately 90 s. The ferry with waterjet thruster produced a less intense cavitating flow; the core reached depths of approximately 6 m, and lasted about 90 s. From this study, it was concluded that multibeam and dual-beam sonar systems with operating frequencies higher than 200 kHz were able to detect cavitating flows in real conditions, as long as they are properly deployed and the data properly analyzed.

  7. Optimal Design of Dual-Hop VLC/RF Communication System With Energy Harvesting

    KAUST Repository

    Rakia, Tamer

    2016-07-28

    In this letter, we consider a dual-hop heterogeneous visible light communication (VLC)/radio frequency (RF) communication system to extend the coverage of VLC systems. Besides detecting the information over VLC link, the relay is able to harvest energy from the first-hop VLC link, by extracting the direct current component of the received optical signal, and uses the harvested energy to retransmit the data to a mobile terminal over the second-hop RF link. We investigate the optimal design of the hybrid system in terms of data rate maximization.

  8. Calibration of dual-energy gamma systems for determining liquid saturations during multiphase flow in soil

    Energy Technology Data Exchange (ETDEWEB)

    Bali, K.M.; Grismer, M.E. [University of California, Cooperative Extension and University of California, Holtville (United States)

    1994-12-31

    The purpose of this study was to calibrate a dual-energy gamma system for simultaneous determination of aqueous and non-aqueous phase liquid (NAPL) in soil column. A dual energy gamma system containing {sup 241}Am and {sup 137}Cs was used to study the infiltration and displacement of aqueous liquid by NAPL and vice versa. Distilled water and Nal solution, and Soltrol 130 were used as fluids. The system was calibrated to minimize errors in liquid saturations due to random nature of gamma photons emission and drift in the photon detection equipment. The measurement accuracy in liquid saturations was substantially improved by increasing counting time and fluid attenuation coefficient. Nal salt was used to increase the attenuation coefficient of water. Measured and predicted liquid saturation during immiscible displacement in soil were consistent with mass balance measurements and anticipated deviations in saturations from probable error calculations. The calibration procedure resulted in a significant improvement in the prediction of liquid saturation using dual-energy gamma system. (author). 8 refs, 4 tabs.

  9. Dual, use-based definition of "system"

    CSIR Research Space (South Africa)

    Gonçalves, DP

    2015-09-01

    Full Text Available The standard definition (ISO 15288, 2008) of the concept of a system is not complete and is the definition of a closed system. Such a definition is inadequate for systems engineering. A use-based definition is proposed which spans the open...

  10. Spatial Distribution of Iron Within the Normal Human Liver Using Dual-Source Dual-Energy CT Imaging.

    Science.gov (United States)

    Abadia, Andres F; Grant, Katharine L; Carey, Kathleen E; Bolch, Wesley E; Morin, Richard L

    2017-05-29

    Explore the potential of dual-source dual-energy (DSDE) computed tomography (CT) to retrospectively analyze the uniformity of iron distribution and establish iron concentration ranges and distribution patterns found in healthy livers. Ten mixtures consisting of an iron nitrate solution and deionized water were prepared in test tubes and scanned using a DSDE 128-slice CT system. Iron images were derived from a 3-material decomposition algorithm (optimized for the quantification of iron). A conversion factor (mg Fe/mL per Hounsfield unit) was calculated from this phantom study as the quotient of known tube concentrations and their corresponding CT values. Retrospective analysis was performed of patients who had undergone DSDE imaging for renal stones. Thirty-seven patients with normal liver function were randomly selected (mean age, 52.5 years). The examinations were processed for iron concentration. Multiple regions of interest were analyzed, and iron concentration (mg Fe/mL) and distribution was reported. The mean conversion factor obtained from the phantom study was 0.15 mg Fe/mL per Hounsfield unit. Whole-liver mean iron concentrations yielded a range of 0.0 to 2.91 mg Fe/mL, with 94.6% (35/37) of the patients exhibiting mean concentrations below 1.0 mg Fe/mL. The most important finding was that iron concentration was not uniform and patients exhibited regionally high concentrations (36/37). These regions of higher concentration were observed to be dominant in the middle-to-upper part of the liver (75%), medially (72.2%), and anteriorly (83.3%). Dual-source dual-energy CT can be used to assess the uniformity of iron distribution in healthy subjects. Applying similar techniques to unhealthy livers, future research may focus on the impact of hepatic iron content and distribution for noninvasive assessment in diseased subjects.

  11. A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

    Directory of Open Access Journals (Sweden)

    Kuo Men

    2015-01-01

    Full Text Available Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT device. Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images. Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously. Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

  12. Dual-Hop VLC/RF Transmission System with Energy Harvesting Relay under Delay Constraint

    KAUST Repository

    Rakia, Tamer

    2017-02-09

    In this paper, we introduce a dual-hop visible light communication (VLC) / radio frequency (RF) transmission system to extend the coverage of indoor VLC systems. The relay between the two hops is able to harvest light energy from different artificial light sources and sunlight entering the room. The relay receives data packet over a VLC channel and uses the harvested energy to retransmit it to a mobile terminal over an RF channel. We develop a novel statistical model for the harvested electrical power and analyze the probability of data packet loss. We define a system design parameter (α ∈ [0, 1)) that controls the time dedicated for excess energy harvesting and data packet retransmission. It was found that the parameter has an optimal value which minimizes the packet loss probability. Further more, this optimal value is independent of the RF channel path loss. However, optimal showed inverse dependence on the packet size.

  13. A Dual-Band Antenna for RF Energy Harvesting Systems in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    A. Bakkali

    2016-01-01

    Full Text Available In this paper, we focus on ambient radio frequency energy available from commercial broadcasting stations in order to provide a system based on RF energy harvesting using a new design of receiving antenna. Several antenna designs have been proposed for use in RF energy harvesting systems, as a pertinent receiving antenna design is highly required since the antenna features can affect the amount of energy harvested. The proposed antenna is aimed at greatly increasing the energy harvesting efficiency over Wi-Fi bands: 2.45 GHz and 5 GHz. This provides a promising alternative energy source in order to power sensors located in harsh environments or remote places, where other energy sources are impracticable. The dual-band antenna can be easily integrated with RF energy harvesting system on the same circuit board. Simulations and measurements were carried out to evaluate the antenna performances and investigate the effects of different design parameters on the antenna performance. The receiving antenna meets the required bandwidth specification and provides peak gain of more than 4 dBi across the operating band.

  14. Dual energy CT

    DEFF Research Database (Denmark)

    Al-Najami, Issam; Drue, Henrik Christian; Steele, Robert

    2017-01-01

    and inaccurate with existing methods. Dual Energy Computed Tomography (DECT) enables qualitative tissue differentiation by simultaneous scanning with different levels of energy. We aimed to assess the feasibility of DECT in quantifying tumor response to neoadjuvant therapy in loco-advanced rectal cancer. METHODS...... to determine the average quantitative parameters; effective-Z, water- and iodine-concentration, Dual Energy Index (DEI), and Dual Energy Ratio (DER). These parameters were compared to the regression in the resection specimen as measured by the pathologist. RESULTS: Changes in the quantitative parameters...

  15. Differentiation of kidney stones using dual-energy CT with and without a tin filter.

    Science.gov (United States)

    Fung, George S K; Kawamoto, Satomi; Matlaga, Brian R; Taguchi, Katsuyuki; Zhou, Xiaodong; Fishman, Elliot K; Tsui, Benjamin M W

    2012-06-01

    The aim of this in vitro study was to examine the capability of three protocols of dual-energy CT imaging in distinguishing calcium oxalate, calcium phosphate, and uric acid kidney stones. A total of 48 calcium oxalate, calcium phosphate, and uric acid human kidney stone samples were placed in individual containers inside a cylindric water phantom and imaged with a dual-energy CT scanner using the following three scanning protocols of different combinations of tube voltage, with and without a tin filter: 80 and 140 kVp without a tin filter, 100 and 140 kVp with a tin filter, and 80 and 140 kVp with a tin filter. The mean attenuation value (in Hounsfield units) of each stone was recorded in both low- and high-energy CT images in each protocol. The dual-energy ratio of the mean attenuation values of each stone was computed for each protocol. For all three protocols, the uric acid stones were significantly different (p filter protocol (AUC, 0.996), the 100- and 140-kVp tin filter protocol (AUC, 0.918), and the 80- and 140-kVp protocol (AUC, 0.871). The tin filter added to the high-energy tube and the use of a wider dual-energy difference are important for improving the stone differentiation capability of dual-energy CT imaging.

  16. A Curve-based Material Recognition Method in MeV Dual-energy X-ray Imaging System

    CERN Document Server

    Chen, Zhi-qiang; Li, Liang

    2014-01-01

    High energy dual-energy X-ray Digital Radiography(DR) imaging is mainly used in material recognition of the cargo inspection. We introduce the development history and the principle of the technology and describe the data process flow of our system. The system corrects original data to get the dual-energy transparence image. Material categories of all points in the image are identified by the classification curve which is related to the X-ray energy spectrum. For the calibration of classification curve, our strategy involves a basic curve calibration and a real-time correction devoted to enhance the classification accuracy. Image segmentation and denoising methods are applied to smooth the image. The image contains more information after colorization. Some results show that our methods achieve the desired effect.

  17. Determination of the area density and composition of alloy film using dual alpha particle energy loss

    Science.gov (United States)

    Ma, Xiaojun; Li, Bo; Gao, Dangzhong; Xu, Jiayun; Tang, Yongjian

    2017-02-01

    A novel method based on dual α-particles energy loss (DAEL) is proposed for measuring the area density and composition of binary alloy films. In order to obtain a dual-energy α-particles source, an ingenious design that utilizes the transmitted α-particles traveling the thin film as a new α-particles source is presented. Using the DAEL technique, the area density and composition of Au/Cu film are determined accurately with an uncertainty of better than 10%. Finally, some measures for improving the combined uncertainty are discussed.

  18. Design and experiment of human hand motion driven electromagnetic energy harvester using dual Halbach magnet array

    Science.gov (United States)

    Salauddin, M.; Park, Jae Y.

    2017-03-01

    We present a dual Halbach array electromagnetic energy harvester that generates significant power from hand shaking vibration. The magnetic-spring configuration is employed for generating sufficient power from the hand motion of irregular and low-frequency vibrations. However, significant power generation at low-frequency vibrations is challenging because the power flow decreases as the frequency decreases; moreover, designing a spring-mass system that is suitable for low-frequency-vibration energy harvesting is difficult. In this work, our proposed device overcomes both of these challenges by using a dual Halbach array and magnetic springs. During the experiment, vibration was applied in a horizontal direction to reduce the gravity effect on the Halbach-array structure. To achieve an increased power generation at low-amplitude and low-frequency vibrations, the magnetic structure of the dual Halbach array and the magnetic springs were optimized in terms of the operating frequency and the power density. A prototype was fabricated and tested both using a vibration exciter and by manual hand-shaking. The fabricated device showed resonant behavior during the vibration exciter test. For the vibration exciter test, the prototype device offers a maximum average power of 2.92 mW to a 62 Ω optimum load, at a 6 Hz resonance frequency and under a 0.5 g acceleration. The prototype device is capable of delivering a maximum average power of 2.27 mW from hand shaking. The fabricated device exhibited a normalized power density 0.46 mW cm‑2g‑2 which is very high compared to the current state-of-the-art devices, representing its ability in powering portable and wearable smart devices from extremely low frequency vibration.

  19. Thoracic applications of dual energy.

    Science.gov (United States)

    Remy-Jardin, Martine; Faivre, Jean-Baptiste; Pontana, Francois; Hachulla, Anne-Lise; Tacelli, Nunzia; Santangelo, Teresa; Remy, Jacques

    2010-01-01

    Recent technological advances in multidetector computed tomography (CT) have led to the introduction of dual-source CT, which allows acquisition of CT data at the same energy or at 2 distinct tube voltage settings during a single acquisition. The advantage of the former is improvement of temporal resolution, whereas the latter offers new options for CT imaging, allowing tissue characterization and functional analysis with morphologic evaluation. The most investigated application has been iodine mapping at pulmonary CT angiography. The material decomposition achievable opens up new options for recognizing substances poorly characterized by single-energy CT. Although it is too early to draw definitive conclusions on dual-energy CT applications, this article reviews the results already reported with the first generation of dual-source CT systems.

  20. Single- and dual energy QCT around acetabular cups in total hip arthroplasty using 3-dimensional segmentation

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder; Andersen, Poul Erik; Torfing, Trine

    Introduction: Bone density measurements around hip implants are challenged by artifacts and the complex anatomy of the acetabulum. We developed 3D segmentation software and used dual energy CT to reduce artifacts. The between-scan agreement and reliability of the software was tested and bone mine...

  1. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images.

    Science.gov (United States)

    Mashouf, S; Lechtman, E; Lai, P; Keller, B M; Karotki, A; Beachey, D J; Pignol, J P

    2014-09-21

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 [Formula: see text] formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  2. Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images

    Science.gov (United States)

    Mashouf, S.; Lechtman, E.; Lai, P.; Keller, B. M.; Karotki, A.; Beachey, D. J.; Pignol, J. P.

    2014-09-01

    Permanent seed implant brachytherapy is currently used for adjuvant radiotherapy of early stage prostate and breast cancer patients. The current standard for calculation of dose around brachytherapy sources is based on the AAPM TG-43 formalism, which generates the dose in a homogeneous water medium. Recently, AAPM TG-186 emphasized the importance of accounting for tissue heterogeneities. We have previously reported on a methodology where the absorbed dose in tissue can be obtained by multiplying the dose, calculated by the TG-43 formalism, by an inhomogeneity correction factor (ICF). In this work we make use of dual energy CT (DECT) images to extract ICF parameters. The advantage of DECT over conventional CT is that it eliminates the need for tissue segmentation as well as assignment of population based atomic compositions. DECT images of a heterogeneous phantom were acquired and the dose was calculated using both TG-43 and TG-43 × \\text{ICF} formalisms. The results were compared to experimental measurements using Gafchromic films in the mid-plane of the phantom. For a seed implant configuration of 8 seeds spaced 1.5 cm apart in a cubic structure, the gamma passing score for 2%/2 mm criteria improved from 40.8% to 90.5% when ICF was applied to TG-43 dose distributions.

  3. Dual energy contrast enhanced breast imaging optimization using contrast to noise ratio

    Science.gov (United States)

    Arvanitis, C. D.; Royle, G.; Speller, R.

    2007-03-01

    The properties of dual energy contrast enhanced breast imaging have been analyzed by imaging a 4 cm breast equivalent phantom consisting of adipose and glandular equivalent plastics. This phantom had superimposed another thin plastic which incorporated a 2 mm deep cylinder filled with iodinated contrast media. The iodine projected thicknesses used for this study was 3 mg/cm2. Low and high energy spectra that straddle the iodine K-edge were used. Critical parameters such as the energy spectra and exposure are discussed, along with post processing by means of nonlinear energy dependent function. The dual energy image was evaluated using the relative contrast to noise ratio of a 2.5 mm x 2.5 mm region of the image at the different iodine concentrations incorporating different breast composition with respect to the noniodinated areas. Optimum results were achieved when the low and high-energy images were used in such a way that relative contrast to noise ratio of the iodine with respect to the background tissue was maximum. A figure of merit suggests that higher noise levels can be tolerated at the benefit of lower exposure. Contrast media kinetics of a phantom incorporating a water flow of 20.4 ml/min through the plastic cylinder suggests that time domain imaging could be performed with this approach. The results suggest that optimization of dual energy contrast enhanced mammography has the potential to lead to the development of perfusion digital mammography.

  4. Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    Sivachandran Paulsamy

    2014-01-01

    Full Text Available In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG for direct coupled stand alone wind energy systems (SAWES. Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  5. Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

    Science.gov (United States)

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  6. Model-Based Iterative Reconstruction for Dual-Energy X-Ray CT Using a Joint Quadratic Likelihood Model.

    Science.gov (United States)

    Zhang, Ruoqiao; Thibault, Jean-Baptiste; Bouman, Charles A; Sauer, Ken D; Hsieh, Jiang

    2014-01-01

    Dual-energy X-ray CT (DECT) has the potential to improve contrast and reduce artifacts as compared to traditional CT. Moreover, by applying model-based iterative reconstruction (MBIR) to dual-energy data, one might also expect to reduce noise and improve resolution. However, the direct implementation of dual-energy MBIR requires the use of a nonlinear forward model, which increases both complexity and computation. Alternatively, simplified forward models have been used which treat the material-decomposed channels separately, but these approaches do not fully account for the statistical dependencies in the channels. In this paper, we present a method for joint dual-energy MBIR (JDE-MBIR), which simplifies the forward model while still accounting for the complete statistical dependency in the material-decomposed sinogram components. The JDE-MBIR approach works by using a quadratic approximation to the polychromatic log-likelihood and a simple but exact nonnegativity constraint in the image domain. We demonstrate that our method is particularly effective when the DECT system uses fast kVp switching, since in this case the model accounts for the inaccuracy of interpolated sinogram entries. Both phantom and clinical results show that the proposed model produces images that compare favorably in quality to previous decomposition-based methods, including FBP and other statistical iterative approaches.

  7. Optimization of dual-energy CT acquisitions for proton therapy using projection-based decomposition.

    Science.gov (United States)

    Vilches-Freixas, Gloria; Létang, Jean Michel; Ducros, Nicolas; Rit, Simon

    2017-09-01

    Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low-energy (LE) and the high-energy (HE) acquisitions. For all spectra combinations, virtual CT projections of the Gammex phantom were simulated with a realistic energy-integrating detector response model. Two situations were simulated: an ideal case without noise (infinite dose) and a realistic situation with Poisson noise corresponding to a 20 mGy total central dose. To determine the optimal dose balance, the proportion of LE-dose with respect to the total dose was varied from 10% to 90% while keeping the central dose constant, for four dual-energy spectra. SPR images were derived using a two-step projection-based decomposition approach. The ranges of 70 MeV, 90 MeV, and 100 MeV proton beams onto the adult female (AF) reference computational phantom of the ICRP were analytically determined from the reconstructed SPR maps. The energy separation between the incident spectra had a strong impact on the SPR precision. Maximizing the incident energy gap reduced image noise. However, the energy gap was not a good metric to evaluate the accuracy of the SPR. In terms of SPR accuracy, a large variability of the optimal spectra was observed when studying each phantom material separately. The SPR accuracy was almost flat in the 30-70% LE-dose range, while the precision showed a minimum slightly shifted in favor of lower LE-dose. Photon noise in the SPR images (20 mGy dose

  8. Cascaded systems analysis of noise reduction algorithms in dual-energy imaging.

    Science.gov (United States)

    Richard, Samuel; Siewerdsen, Jeffrey H

    2008-02-01

    An important aspect of dual-energy (DE) x-ray image decomposition is the incorporation of noise reduction techniques to mitigate the amplification of quantum noise. This article extends cascaded systems analysis of imaging performance to DE imaging systems incorporating linear noise reduction algorithms. A general analytical formulation of linear DE decomposition is derived, with weighted log subtraction and several previously reported noise reduction algorithms emerging as special cases. The DE image noise-power spectrum (NPS) and modulation transfer function (MTF) demonstrate that noise reduction algorithms impart significant, nontrivial effects on the spatial-frequency-dependent transfer characteristics which do not cancel out of the noise-equivalent quanta (NEQ). Theoretical predictions were validated in comparison to the measured NPS and MTF. The resulting NEQ was integrated with spatial-frequency-dependent task functions to yield the detectability index, d', for evaluation of DE imaging performance using different decomposition algorithms. For a 3 mm lung nodule detection task, the detectability index varied from d' 2.5 (i.e., nodule clearly visible) for "anti-correlated noise reduction" (ACNR) or "simple-smoothing of the high-energy image" (SSH) algorithms applied to soft-tissue or bone-only decompositions, respectively. Optimal dose allocation (A*, the fraction of total dose delivered in the low-energy projection) was also found to depend on the choice of noise reduction technique. At fixed total dose, multi-function optimization suggested a significant increase in optimal dose allocation from A* = 0.32 for conventional log subtraction to A* = 0.79 for ACNR and SSH in soft-tissue and bone-only decompositions, respectively. Cascaded systems analysis extended to the general formulation of DE image decomposition provided an objective means of investigating DE imaging performance across a broad range of acquisition and decomposition algorithms in a manner that

  9. Investigation of dual-energy X-ray photon counting using a cadmium telluride detector with dual-energy selection electronics

    Science.gov (United States)

    Sato, Eiichi; Kosuge, Yoshiyuki; Yamanome, Hayato; Mikata, Akiko; Miura, Tatsuya; Oda, Yasuyuki; Ishii, Tomotaka; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Watanabe, Manabu; Kusachi, Shinya

    2017-01-01

    To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have developed a dual-energy X-ray photon counter with a cadmium telluride (CdTe) detector and two energy-selecting devices (ESDs). The ESD consists of two comparators and a microcomputer (MC). X-ray photons are detected using the CdTe detector, and the event pulses from a shaping amplifier are sent to two ESDs simultaneously to determine two energy ranges. X-ray photons in the two ranges are counted using the MCs, and the logical pulses from the MCs are input to frequency-to-voltage converters (FVCs). The outputs from the two FVCs are input to a personal computer through an analog-to-digital converter to carry out dual-energy computed tomography. The tube voltage and current were 80 kV and 8.5 μA, respectively. Two tomograms were obtained simultaneously with two energy ranges. K-edge CT using iodine and gadolinium media was carried out utilizing two energy ranges of 33-45 and 50-65 keV, respectively. The maximum count rate was 6.8 kilocounts per second with energies ranging from 10 to 80 keV, and the exposure time for tomography was 9.8 min.

  10. Dual-energy CT for detection of endoleaks after endovascular abdominal aneurysm repair: usefulness of colored iodine overlay.

    Science.gov (United States)

    Ascenti, Giorgio; Mazziotti, Silvio; Lamberto, Salvatore; Bottari, Antonio; Caloggero, Simona; Racchiusa, Sergio; Mileto, Achille; Scribano, Emanuele

    2011-06-01

    The purpose of our study was to evaluate the value of dual-source dual-energy CT with colored iodine overlay for detection of endoleaks after endovascular abdominal aortic aneurysm repair. We also calculated the potential dose reduction by using a dual-energy CT single-phase protocol. From November 2007 to November 2009, 74 patients underwent CT angiography 2-7 days after endovascular repair during single-energy unenhanced and dual-energy venous phases. By using dual-energy software, the iodine overlay was superimposed on venous phase images with different percentages ranging between 0 (virtual unenhanced images) and 50-75% to show the iodine in an orange color. Two blinded readers evaluated the data for diagnosis of endoleaks during standard unenhanced and venous phase images (session 1, standard of reference) and virtual unenhanced and venous phase images with colored iodine overlay images (session 2). We compared the effective dose radiation of a single-energy biphasic protocol with that of a single-phase dual-energy protocol. The diagnostic accuracy of session 2 was calculated. The mean dual-energy effective dose was 7.27 mSv. By using a dual-energy single-phase protocol, we obtained a mean dose reduction of 28% with respect to a single-energy biphasic protocol. The diagnostic accuracy of session 2 was: 100% sensitivity, 100% specificity, 100% negative predictive value, and 100% positive predictive value. Statistically significant differences in the level of confidence for endoleak detection between the two sessions were found by reviewers for scores 3-5. Dual-energy CT with colored iodine overlay is a useful diagnostic tool in endoleak detection. The use of a dual-energy single-phase study protocol will lower radiation exposure to patients.

  11. Dual-mode, high energy utilization system concept for mars missions

    Science.gov (United States)

    El-Genk, Mohamed S.

    2000-01-01

    This paper describes a dual-mode, high energy utilization system concept based on the Pellet Bed Reactor (PeBR) to support future manned missions to Mars. The system uses proven Closed Brayton Cycle (CBC) engines to partially convert the reactor thermal power to electricity. The electric power generated is kept the same during the propulsion and the power modes, but the reactor thermal power in the former could be several times higher, while maintaining the reactor temperatures almost constant. During the propulsion mode, the electric power of the system, minus ~1-5 kWe for house keeping, is used to operate a Variable Specific Impulse Magnetoplasma Rocket (VASIMR). In addition, the reactor thermal power, plus more than 85% of the head load of the CBC engine radiators, are used to heat hydrogen. The hot hydrogen is mixed with the high temperature plasma in a VASIMR to provide both high thrust and Isp>35,000 N.s/kg, reducing the travel time to Mars to about 3 months. The electric power also supports surface exploration of Mars. The fuel temperature and the inlet temperatures of the He-Xe working fluid to the nuclear reactor core and the CBC turbine are maintained almost constant during both the propulsion and power modes to minimize thermal stresses. Also, the exit temperature of the He-Xe from the reactor core is kept at least 200 K below the maximum fuel design temperature. The present system has no single point failure and could be tested fully assembled in a ground facility using electric heaters in place of the nuclear reactor. Operation and design parameters of a 40-kWe prototype are presented and discussed to illustrate the operation and design principles of the proposed system. .

  12. A Dual-Band Antenna for RF Energy Harvesting Systems in Wireless Sensor Networks

    OpenAIRE

    A. Bakkali; Pelegri-Sebastia, J.; Sogorb, T.; V. Llario; Bou-Escriva, A.

    2016-01-01

    In this paper, we focus on ambient radio frequency energy available from commercial broadcasting stations in order to provide a system based on RF energy harvesting using a new design of receiving antenna. Several antenna designs have been proposed for use in RF energy harvesting systems, as a pertinent receiving antenna design is highly required since the antenna features can affect the amount of energy harvested. The proposed antenna is aimed at greatly increasing the energy harves...

  13. A review of the use of dual-energy X-ray absorptiometry (DXA in rheumatology

    Directory of Open Access Journals (Sweden)

    Tanner SB

    2012-12-01

    Full Text Available S Bobo Tanner, Charles F Moore JrDivision of Rheumatology, Vanderbilt University Medical Center, Nashville, TN, USAAbstract: The principal use of dual-energy X-ray absorptiometry (DXA is to diagnose and monitor osteoporosis and therefore reduce fracture risk, associated morbidity, and mortality. In the field of rheumatology, DXA is an essential component of patient care because of both rheumatologists’ prescription of glucocorticoid treatment as well as the effects of rheumatological diseases on bone health. This review will summarize the use of DXA in the field of rheumatology, including the concern for glucocorticoid-induced osteoporosis, as well as the association of osteoporosis with a sampling of such rheumatologic conditions as rheumatoid arthritis (RA, systemic lupus erythematosus, ankylosing spondylitis, juvenile idiopathic arthritis, and scleroderma or systemic sclerosis. Medicare guidelines recognize the need to perform DXA studies in patients treated with glucocorticoids, and the World Health Organization FRAX tool uses data from DXA as well as the independent risk factors of RA and glucocorticoid use to predict fracture risk. However, patient access to DXA measurement in the US is in jeopardy as a result of reimbursement restrictions. DXA technology can simultaneously be used to discover vertebral fractures with vertebral fracture assessment and provide patients with a rapid, convenient, and low-radiation opportunity to clarify future fracture and comorbidity risks. An emerging use of DXA technology is the analysis of body composition of RA patients and thus the recognition of “rheumatoid cachexia,” in which patients are noted to have a worse prognosis even when the RA appears well controlled. Therefore, the use of DXA in rheumatology is an important tool for detecting osteoporosis, reducing fracture risk and unfavorable outcomes in rheumatological conditions. The widespread use of glucocorticoids and the underlying

  14. Using MCNPX and GEANT code to study the energy response of dual energy detectors; Utilizacion del codigo MCNP y GEANT para el estudio de la respuesta energetica de detectores de energia dual

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Moreda, D.; Miro, R.; Verdu, G.

    2011-07-01

    The use of radiation detectors Dual energy (dual energy) is a powerful tool for identification of materials subjected to X-ray analysis. Given a photon spectrum emitted by an X-ray tube, at low energies, the absorption of radiation depends mainly on the effective atomic number and thickness of the material. In contrast, higher energy levels, above 100 kilovolts, the energy absorbed depends, above all, the material density.

  15. An online model-based method for state of energy estimation of lithium-ion batteries using dual filters

    Science.gov (United States)

    Dong, Guangzhong; Chen, Zonghai; Wei, Jingwen; Zhang, Chenbin; Wang, Peng

    2016-01-01

    The state-of-energy of lithium-ion batteries is an important evaluation index for energy storage systems in electric vehicles and smart grids. To improve the battery state-of-energy estimation accuracy and reliability, an online model-based estimation approach is proposed against uncertain dynamic load currents and environment temperatures. Firstly, a three-dimensional response surface open-circuit-voltage model is built up to improve the battery state-of-energy estimation accuracy, taking various temperatures into account. Secondly, a total-available-energy-capacity model that involves temperatures and discharge rates is reconstructed to improve the accuracy of the battery model. An extended-Kalman-filter and particle-filter based dual filters algorithm is then developed to establish an online model-based estimator for the battery state-of-energy. The extended-Kalman-filter is employed to update parameters of the battery model using real-time battery current and voltage at each sampling interval, while the particle-filter is applied to estimate the battery state-of-energy. Finally, the proposed approach is verified by experiments conducted on a LiFePO4 lithium-ion battery under different operating currents and temperatures. Experimental results indicate that the battery model simulates battery dynamics robustly with high accuracy, and the estimates of the dual filters converge to the real state-of-energy within an error of ±4%.

  16. Using dual-energy x-ray imaging to enhance automated lung tumor tracking during real-time adaptive radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Menten, Martin J., E-mail: martin.menten@icr.ac.uk; Fast, Martin F.; Nill, Simeon; Oelfke, Uwe, E-mail: uwe.oelfke@icr.ac.uk [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)

    2015-12-15

    Purpose: Real-time, markerless localization of lung tumors with kV imaging is often inhibited by ribs obscuring the tumor and poor soft-tissue contrast. This study investigates the use of dual-energy imaging, which can generate radiographs with reduced bone visibility, to enhance automated lung tumor tracking for real-time adaptive radiotherapy. Methods: kV images of an anthropomorphic breathing chest phantom were experimentally acquired and radiographs of actual lung cancer patients were Monte-Carlo-simulated at three imaging settings: low-energy (70 kVp, 1.5 mAs), high-energy (140 kVp, 2.5 mAs, 1 mm additional tin filtration), and clinical (120 kVp, 0.25 mAs). Regular dual-energy images were calculated by weighted logarithmic subtraction of high- and low-energy images and filter-free dual-energy images were generated from clinical and low-energy radiographs. The weighting factor to calculate the dual-energy images was determined by means of a novel objective score. The usefulness of dual-energy imaging for real-time tracking with an automated template matching algorithm was investigated. Results: Regular dual-energy imaging was able to increase tracking accuracy in left–right images of the anthropomorphic phantom as well as in 7 out of 24 investigated patient cases. Tracking accuracy remained comparable in three cases and decreased in five cases. Filter-free dual-energy imaging was only able to increase accuracy in 2 out of 24 cases. In four cases no change in accuracy was observed and tracking accuracy worsened in nine cases. In 9 out of 24 cases, it was not possible to define a tracking template due to poor soft-tissue contrast regardless of input images. The mean localization errors using clinical, regular dual-energy, and filter-free dual-energy radiographs were 3.85, 3.32, and 5.24 mm, respectively. Tracking success was dependent on tumor position, tumor size, imaging beam angle, and patient size. Conclusions: This study has highlighted the influence of

  17. SU-D-204-01: Dual-Energy Calibration for Breast Density Measurement Using Spectral Mammography

    Energy Technology Data Exchange (ETDEWEB)

    Ding, H; Cho, H; Kumar, N; Sennung, D; Molloi, S [Department of Radiological Sciences, University of California, Irvine, CA (United States)

    2015-06-15

    Purpose: To investigate the feasibility of minimizing the systematic errors in dual-energy breast density quantification induced by the use of tissue-equivalent plastic phantoms as the calibration basis materials. Methods: Dual-energy calibration using tissue-equivalent plastic phantoms was performed on a spectral mammography system based on scanning multi-slit Si strip photon-counting detectors. The plastic phantom calibration used plastic water and adipose-equivalent phantoms as the basis materials, which have different x-ray attenuation properties compared to water and lipid in actual breast tissue. Two methods were used to convert the dual-energy decomposition measurements in plastic phantom thicknesses into true water and lipid basis. The first method was based entirely on the theoretical x-ray attenuation coefficients of the investigated materials in the mammographic energy range. The conversion matrix was determined from least-squares fitting of the target material using the reported attenuation coefficients of water and lipid. The second method was developed based on experimental calibrations, which measured the low-and high-energy signals of pure water and lipid of known thicknesses. A non-linear rational function was used to correlate the decomposed thicknesses to the known values, so that the conversion coefficients can be determined. Both methods were validated using independent measurements of water and lipid mixture phantoms. The correlation of the dual-energy decomposition measurements and the known values were studied with linear regression analysis. Results: There was an excellent linear correlation between the converted water thicknesses and the known values. The slopes of the linear fits were determined to be 0.63 and 1.03 for the simulation and experimental results, respectively. The non-linear fitting in the experimental approach reduced the root-mean-square (RMS) errors from approximately 3.4 mm to 1.5 mm. Conclusion: The results suggested

  18. Enhanced acoustoelectric coupling in acoustic energy harvester using dual Helmholtz resonators.

    Science.gov (United States)

    Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling

    2013-10-01

    In this paper, enhanced acoustoelectric transduction in an acoustic energy harvester using dual Helmholtz resonators has been reported. The harvester uses a pair of cavities mechanically coupled with a compliant perforated plate to enhance the acoustic coupling between the cavity and the plate. The experimental results show that the volume optimization of the second cavity can significantly increase the generated electric voltage up to 400% and raise the output power to 16 times as large as that of a harvester using a single Helmholtz resonator at resonant frequencies primarily related to the plate.

  19. Clinical usefulness of calcaneal measurements using dual energy x-ray absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Kohno, Jun [Nagasaki Saiseikai Hospital (Japan); Nakata, Tomoko; Ito, Masako

    1999-07-01

    To investigate the clinical usefulness of calcaneal measurement using dual-energy x-ray absorptiometry (DXA), the ability to detect bone loss and fracture risk were evaluated in comparison with spinal bone mineral density (BMD) measured using DXA and quantitative CT (QCT) and with calcaneal quantitative ultrasound (QUS). Furthermore, to investigate the region in calcaneus in which to detect bone change sensitively, the ability to detect bone loss and fracture risk were also evaluated using new regions of interest (ROIs) that were manually defined. The subjects were 165 healthy women, and 188 female patients with fracture, estrogen deficiency, and steroid-induced osteoporosis. Calcaneal BMD with some manually defined ROIs showed lower precision and less sensitivity in detecting bone loss than BMD measured with automatically defined ROIs. Calcaneal DXA, spinal DXA, and QCT demonstrated significant age-related bone loss, and all measurements could discriminate fracture cases from non-fracture cases. Calcaneal DXA could discriminate the bone loss associated with estrogen deficiency as well as spinal DXA. Furthermore, calcaneal measurements showed a greater ability to detect steroid-induced bone loss than spinal DXA, probably because this group included subjects of advanced age with spondylosis. In conclusion, calcaneal DXA is useful to assess BMD in subjects who are not suitable for spinal measurement, although the ability to detect age-related bone loss in calcaneal DXA is less than in spinal measurements. (author)

  20. SU-C-18C-03: Dual-Energy X-Ray Fluoroscopy Imaging System

    Energy Technology Data Exchange (ETDEWEB)

    Virshup, G; Richmond, M; Mostafavi, H; Ganguly, A [Ginzton Technology Center, Varian Medical Systems Inc, Palo Alto, CA (United States); Fu, D [Ruier Medical, Wuxi, Jiangsu Province (China)

    2014-06-01

    Purpose: This work studies the clinical utility of dual energy (DE) subtraction fluoroscopy for fiducial-free tumor tracking in lung radiation therapy (RT). Improvement in tumor visualization and quantification of tumor shift within a breathing cycle were analyzed. Methods: Twenty subjects who were undergoing RT for lung cancer were recruited following institutional review board approval. The subjects had a range of tumor sizes, locations in the lungs, and body sizes. An x-ray imaging system was setup with the following components: (a) x-ray tube (Varian G-242, Varian Medical Systems (VMS), CA) (b) flat panel detector (4030CB, VMS, CA) and (c) x-ray generator (EPS 50RF, EMD, Canada). Firmware and software modifications were made to the generator to allow 10 x-ray pulse pairs with alternating low/high kV, 100 ms apart for ∼4s (one breathing cycle). Images were obtained at 4 angles: 0°, 45°, 90° and 135°. Weighted subtraction of a kV-pair image set was used to create a “bone-free” image of the lungs. The 2D tumor-shift in each subtracted image and the 3D shift during a breathing cycle was calculated using all views. Results: The subjects enrolled had the following statistics: average age 62.3±7.1 years, 5 female/15 male, 11 had tumors on the right and 9 on the left and the average tumor size was ∼31.4±10.8 mm. X-ray imaging conditions for the pulse pairs were: 70/120 kVp, 280/221 mA and 65/8 ms. For views where these parameters were insufficient 80/130 kVp, 280/221 mA and 60/12 ms was used. Tumor visibility improved for 0°, 45°, 90° and 135° in 100%, 55%, 75% and 80% of the cases respectively. Tumor shift during a breathing cycle was: 2.4±1.0 mm AP, 2.7±1.4 mm LR and 7.6±4.8 mm IS. Conclusion: DE subtraction fluoroscopy allowed improved visualization and quantification of movement of tumors in the lungs during a breathing cycle. This study was entirely funded by Varian Medical Systems.

  1. Adaptive lesion formation using dual mode ultrasound array system

    Science.gov (United States)

    Liu, Dalong; Casper, Andrew; Haritonova, Alyona; Ebbini, Emad S.

    2017-03-01

    We present the results from an ultrasound-guided focused ultrasound platform designed to perform real-time monitoring and control of lesion formation. Real-time signal processing of echogenicity changes during lesion formation allows for identification of signature events indicative of tissue damage. The detection of these events triggers the cessation or the reduction of the exposure (intensity and/or time) to prevent overexposure. A dual mode ultrasound array (DMUA) is used for forming single- and multiple-focus patterns in a variety of tissues. The DMUA approach allows for inherent registration between the therapeutic and imaging coordinate systems providing instantaneous, spatially-accurate feedback on lesion formation dynamics. The beamformed RF data has been shown to have high sensitivity and specificity to tissue changes during lesion formation, including in vivo. In particular, the beamformed echo data from the DMUA is very sensitive to cavitation activity in response to HIFU in a variety of modes, e.g. boiling cavitation. This form of feedback is characterized by sudden increase in echogenicity that could occur within milliseconds of the application of HIFU (see http://youtu.be/No2wh-ceTLs for an example). The real-time beamforming and signal processing allowing the adaptive control of lesion formation is enabled by a high performance GPU platform (response time within 10 msec). We present results from a series of experiments in bovine cardiac tissue demonstrating the robustness and increased speed of volumetric lesion formation for a range of clinically-relevant exposures. Gross histology demonstrate clearly that adaptive lesion formation results in tissue damage consistent with the size of the focal spot and the raster scan in 3 dimensions. In contrast, uncontrolled volumetric lesions exhibit significant pre-focal buildup due to excessive exposure from multiple full-exposure HIFU shots. Stopping or reducing the HIFU exposure upon the detection of such an

  2. Universal and robust electron-density assessment using dual-energy CT

    CERN Document Server

    Möhler, Christian; Richter, Christian; Greilich, Steffen

    2016-01-01

    Dual-energy computed tomography (DECT) can be used to acquire an electron-density and an effective-atomic-number image of the scanned object. We show that a simple one-parametric formula for the electron density follows from a basic assumption on the functional form of the cross section. This assumption is valid in the energy range relevant to a CT scanner and in the atomic number range relevant to human tissue. We propose a robust calibration for the electron-density equation, which is easily applicable using standard equipment, and provide parameters for two clinical DECT scanners. For the application in proton and ion radiation therapy, we suggest to use the relative cross section instead of the effective atomic number, as it enables a proper treatment of tissue mixtures, while providing the same contrast for diagnostic or delineation purposes.

  3. Correlation Between Dual-energy and Perfusion CT in Patients with Focal Liver Lesions Using Third-generation Dual-source CT Scanner.

    Science.gov (United States)

    Xu, Jia; Zheng, Yongchang; Wang, Xuan; Xue, Huadan; Wang, Shitian; Liang, Jixiang; Jin, Zhengyu

    2017-02-20

    Objective To compare measurements of dual-energy CT iodine map parameters and liver perfusion CT parameters in patients with focal liver lesions using a third-generation dual-source CT scanner. Methods Between November 2015 and August 2016,33 patients with non-cystic focal lesions of liver were enrolled in this study. CT examinations were performed with a third-generation dual-source CT. The study CT protocol included a perfusion CT and dual-energy arterial and portal venous scans,with a time interval of 15 minutes. Iodine attenuation was measured at five region of interests including areas of high,medium,and low density within the lesion,as well as right and left liver parenchyma from the iodine map,while arterial liver perfusion (ALP),portal venous liver perfusion (PVP),and hepatic perfusion index (HPI) at the same location were measured from perfusion CT. The Pearson product-moment correlation coefficient was used to evaluate the relationship between iodine attenuation and perfusion parameters. Results The iodine attenuation at arterial phase showed significant intra-individual correlation with ALP (r=0.812,95% CI=0.728-0.885,Pperfusion CT [(14.53±0.45)mSv](t=25.212,P<0.001). Conclusion Iodine attenuation from arterial phase of dual energy CT demonstrates significant correlation with ALP and PVP,and iodine attenuation from portal venous phase demonstrates significant correlation with PVP.

  4. Dual-energy in mammography: feasibility study

    Science.gov (United States)

    Jafroudi, Hamid; Lo, Shih-Chung B.; Li, Huai; Steller Artz, Dorothy E.; Freedman, Matthew T.; Mun, Seong K.

    1996-04-01

    The purpose of this work is to examine the feasibility of dual-energy techniques to enhance the detection of microcalcifications in digital mammography. The digital mammography system used in this study consists of two different mammography systems; one is the conventional mammography system with molybdenum target and Mo filtration and the other is the clinical version of a low dose x-ray system with tungsten target and aluminum filtration. The low dose system is optimized for screen-film mammography with a highly efficient scatter rejection device built by Fischer Imaging Systems for evaluation at NIH. The system was designed by the University of Southern California based on multiparameter optimization techniques. Prototypes of this system have been constructed and evaluated at the Center for Devices and Radiological Health. The digital radiography system is based on the Fuji 9000 computed radiography (CR) system which uses a storage phosphor imaging plate as the receptor. High resolution plates (HR-V) are used in this study. Dual-energy is one technique to reduce the structured noise associated with the complexity of the background of normal anatomy surrounding a lesion. This can be done by taking the advantage of the x-ray attenuation characteristics of two different structures such as soft tissue and bone in chest radiography. We have applied this technique to the detection of microcalcifications in mammography. The overall system performance based on this technique is evaluated. Results presented are based on the evaluation of phantom images.

  5. SU-E-I-38: Improved Metal Artifact Correction Using Adaptive Dual Energy Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Dong, X; Elder, E; Roper, J; Dhabaan, A [Winship Cancer Institute of Emory University (United States)

    2015-06-15

    Purpose: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Methods: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Results: Highly attenuating copper rods cause severe streaking artifacts on standard CT images. EDEC improves the image quality, but cannot eliminate the streaking artifacts. Compared to EDEC, the proposed ADEC method further reduces the streaking resulting from metallic inserts and beam-hardening effects and obtains material decomposition images with significantly improved accuracy. Conclusion: We propose an adaptive dual energy calibration method to correct for metal artifacts. ADEC is evaluated with the Shepp-Logan phantom, and shows superior metal artifact correction performance. In the future, we will further evaluate the performance of the proposed method with phantom and patient data.

  6. Coronary calcium visualization using dual energy chest radiography with sliding organ registration

    Science.gov (United States)

    Wen, Di; Nye, Katelyn; Zhou, Bo; Gilkeson, Robert C.; Wilson, David L.

    2016-03-01

    Coronary artery calcification (CAC) is the lead biomarker for atherosclerotic heart disease. We are developing a new technique to image CAC using ubiquitously ordered, low cost, low radiation dual energy (DE) chest radiography (using the two-shot GE Revolution XRd system). In this paper, we proposed a novel image processing method (CorCalDx) based on sliding organ registration to create a bone-image-like, coronary calcium image (CCI) that significantly reduces motion artifacts and improves CAC conspicuity. Experiments on images of a physical dynamic cardiac phantom showed that CorCalDx reduced 73% of the motion artifact area as compared to standard DE over a range of heart rates up to 90 bpm and varying x-ray radiation exposures. Residual motion artifact in the phantom CCI is greatly suppressed in gray level and area (0.88% of the heart area). In a Functional Measurement Test (FMT) with 20 clinical exams, image quality improvement of CorCalDx against standard DE (measured from -10 to +10) was significantly suggested (p<0.0001) by three radiologists for cardiac motion artifacts (7.2+/-2.1) and cardiac anatomy visibility (6.1+/-3.5). CorCalDx was always chosen best in every image tested. In preliminary assessments of 12 patients with 18 calcifications, 90% of motion artifact regions in standard DE results were removed in CorCalDx results, with 100% sensitivity of calcification detection, showing great potential of CorCalDx to improve CAC detection and grading in DE chest radiography.

  7. Efficient use of unutilized energy and holonic energy system. Miriyo energy katsuyo to energy yuzu system

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, M. (Shibaura Institute of Technology, Tokyo (Japan))

    1992-05-10

    In the present report, opinion is given about the activation of unutilized energy and circulative use of energy. The fuel imported to Japan is utilized by 35% and its balance of 65% is used to go for nothing. An estimation example of unutilized energy in Tokyo Metropolis indicates that, generally high on the exhaust heat, the denpendency is 34.5 and 31.4% on the refuse treatment plants and sewage treatment plants, respectively. The exhaust heat from the refuse treatment plants must be activated under a repowering system to heighten both the output power and efficiency, for which system the existing steam turbine is to be installed commonly with a gas turbine to structure a combined cycle. Then, needed are the circulative use and industrial purpose repowering of energy among different categories of both public and private industries. From the viewpoint of cogeneration system to require the supply and demand to be balanced, it is advisable to circulatively use and repower the energy among and by many producers of unutilized energy. Cooperation is needed of syndical and other organizations. A further need in of large capacity thermal source heat pump, and which is to utilize a low temperature however comparatively large capacity thermal source generated in the sewage treastment and other plants. The engine-driven heat pump is prior to the electrically driven one. 2 figs.

  8. Improving the mid-infrared energy absorption efficiency by using a dual-band metamaterial absorber

    Institute of Scientific and Technical Information of China (English)

    Nan Zhang; Peiheng Zhoun; Shifeng Zou; Xiaolong Weng; Jianliang Xie; Longjiang Deng

    2014-01-01

    In this paper, a dual-band mid-infrared metamaterial absorber was proposed to improve the energy absorption efficiency. Up to 99%absorption was obtained at 9.03 and 11.83μm in the simulation, and each absorption band can be tuned by the dielectric spacing layer, i.e., the dielectric constant and its thickness. The dual-band absorption mechanism was analyzed, and the quite well absorption performance at large incident angles was also presented. The results of this study can be applied in the field of thermal absorbing and solar energy harvesting.

  9. Dual cure photocatalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    DeVoe, R.J.; Brown-Wensley, K.A.; Holmes, G.L.; Mathis, M.D.; McCormick, F.B.; Palazzotto, M.C.; Spurgeon, K.M. (Minnesota Mining and Mfg. Co., St. Paul, MN (USA). Corporate Research Labs.)

    1990-01-01

    A family of dual cure photocatalyst systems is being developed to be used in the solventless processing of organic coatings. The photocatalyst systems consist of organometallic compounds often in combination with other agents. Upon photolysis, the photocatalyst system generates a Lewis acid and a free radical. The Lewis acid can initiate the polymerization of epoxies or the addition of isocyanates and polyols to form polyurethanes while the free radical can initiate the polymerization of acrylates. The performance of the various photocatalyst systems will be compared on the basis of the physical properties of the cured compositions they produce. 17 figs.

  10. Simulation on Dual-stream Transmission System of Unmanned Tracked Armored Vehicle Using ADAMS

    Directory of Open Access Journals (Sweden)

    Sun Wei

    2015-01-01

    Full Text Available For the dual-stream transmission system of unmanned tracked armored vehicle, simulation analysis is carried out. Using SolidWorks to establish three-dimensional model of its chassis, the result of the simulation is processed in AdAMS/Solver. The simulation results are showed in lines. Comparative analysis for each simulation lines is conducted, and it verifies the feasibility of the dual-stream transmission system.

  11. Dual energy with dual source CT and kVp switching with single source CT: a comparison of dual energy performance

    Science.gov (United States)

    Grasruck, M.; Kappler, S.; Reinwand, M.; Stierstorfer, K.

    2009-02-01

    Stimulated by the introduction of clinical dual source CT, the interest in dual energy methods has been increasing in the past years. Whereas the potential of material decomposition by dual energy methods is known since the early 1980ies, the realization of dual energy methods is a wide field of today's research. Energy separation can be achieved with energy selective detectors or by varying X-ray source spectra. This paper focuses on dual energy techniques with varying X-ray spectra. These can be provided by dual source CT devices, operated with different kVp settings on each tube. Excellent spectral separation is the key property for use in clinical routine. The drawback of higher cost for two tubes and two detectors leads to an alternative realization, where a single source CT yields different spectra by fast kVp switching from reading to reading. This provides access to dual-energy methods in single source CT. However, this technique comes with some intrinsic limitations. The maximum X-ray flux is reduced in comparison to the dual source system. The kVp rise and fall time between each reading reduces the spectral separation. In comparison to dual source CT, for a constant number of projections per energy spectrum the temporal resolution is reduced; a reasonable trade of between reduced numbers of projection and limited temporal resolution has to be found. The overall dual energy performance is the guiding line for our investigations. We present simulations and measurements which benchmark both solutions in terms of spectral behavior, especially of spectral separation.

  12. Virtual non-contrast CT using dual energy spectral CT: Feasibility of coronary artery calcium scoring

    Energy Technology Data Exchange (ETDEWEB)

    Song, In Young; Yi, Jeong Geun; Park, Jeong Hee [Dept. of Radiology, Konkuk University School of Medicine, Seoul (Korea, Republic of); Lee, Sung Mok; Lee, Kyung Soo; Chung, Myung Jin [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated VNC images were reconstructed using two kinds of 2-material decomposition algorithms (material density iodine-water pair [MDW], material density iodine-calcium pair [MDC]) and a material suppressed algorithm (material suppressed iodine [MSI]). Two readers independently quantified calcium on VNC and TNC images. The Spearman correlation coefficient test and Bland-Altman method were used for statistical analyses. Coronary artery calcium scores from all three VNC images showed excellent correlation with those from the TNC images (Spearman's correlation coefficient [ρ] = 0.94, 0.88, and 0.89 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Measured coronary calcium volumes from VNC images also correlated well with those from TNC images (ρ = 0.92, 0.87, and 0.91 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Among the three VNC images, coronary calcium from MDW correlated best with that from TNC. The coronary artery calcium scores and volumes were significantly lower from the VNC images than from the TNC images (p < 0.001 for all pairs). The use of VNC images from contrast-enhanced CT using dual-energy material decomposition/suppression is feasible for coronary calcium scoring. The absolute value from VNC tends to be smaller than that from TNC.

  13. Stabilizing dual-energy X-ray computed tomography reconstructions using patch-based regularization

    CERN Document Server

    Tracey, Brian H

    2014-01-01

    Recent years have seen growing interest in exploiting dual- and multi-energy measurements in computed tomography (CT) in order to characterize material properties as well as object shape. Material characterization is performed by decomposing the scene into constitutive basis functions, such as Compton scatter and photoelectric absorption functions. While well motivated physically, the joint recovery of the spatial distribution of photoelectric and Compton properties is severely complicated by the fact that the data are several orders of magnitude more sensitive to Compton scatter coefficients than to photoelectric absorption, so small errors in Compton estimates can create large artifacts in the photoelectric estimate. To address these issues, we propose a model-based iterative approach which uses patch-based regularization terms to stabilize inversion of photoelectric coefficients, and solve the resulting problem though use of computationally attractive Alternating Direction Method of Multipliers (ADMM) solu...

  14. Learning-Based Object Identification and Segmentation Using Dual-Energy CT Images for Security.

    Science.gov (United States)

    Martin, Limor; Tuysuzoglu, Ahmet; Karl, W Clem; Ishwar, Prakash

    2015-11-01

    In recent years, baggage screening at airports has included the use of dual-energy X-ray computed tomography (DECT), an advanced technology for nondestructive evaluation. The main challenge remains to reliably find and identify threat objects in the bag from DECT data. This task is particularly hard due to the wide variety of objects, the high clutter, and the presence of metal, which causes streaks and shading in the scanner images. Image noise and artifacts are generally much more severe than in medical CT and can lead to splitting of objects and inaccurate object labeling. The conventional approach performs object segmentation and material identification in two decoupled processes. Dual-energy information is typically not used for the segmentation, and object localization is not explicitly used to stabilize the material parameter estimates. We propose a novel learning-based framework for joint segmentation and identification of objects directly from volumetric DECT images, which is robust to streaks, noise and variability due to clutter. We focus on segmenting and identifying a small set of objects of interest with characteristics that are learned from training images, and consider everything else as background. We include data weighting to mitigate metal artifacts and incorporate an object boundary field to reduce object splitting. The overall formulation is posed as a multilabel discrete optimization problem and solved using an efficient graph-cut algorithm. We test the method on real data and show its potential for producing accurate labels of the objects of interest without splits in the presence of metal and clutter.

  15. Dual Isotope SPECT Study With Epilepsy Patients Using Semiconductor SPECT System.

    Science.gov (United States)

    Shiga, Tohru; Suzuki, Atsuro; Sakurai, Kotarou; Kurita, Tsugiko; Takeuchi, Wataru; Toyonaga, Takuya; Hirata, Kenji; Kobashi, Keiji; Katoh, Chietsugu; Kubo, Naoki; Tamaki, Nagara

    2017-09-01

    We developed a prototype CdTe SPECT system with 4-pixel matched collimator for brain study. This system provides high-energy-resolution (6.6%), high-sensitivity (220 cps/MBq/head), and high-spatial-resolution images. The aim of this study was to evaluate dual-isotope study of CBF and central benzodiazepine receptor (BZR) images using Tc-ECD and I-IMZ with the new SPECT system in patients with epilepsy comparing with single-isotope study using the conventional scintillation gamma camera. This study included 13 patients with partial epilepsy. The BZR images were acquired at 3 hours after I-IMZ injection for 20 minutes. The images of IMZ were acquired with a conventional 3-head scintillation gamma camera. After BZR image acquisition with the conventional camera, Tc-ECD was injected, and CBF and BZR images were acquired simultaneously 5 minutes after ECD injection with the new SPECT system. The CBF images were also acquired with the conventional camera on separate days. The findings were visually analyzed, and 3D-SSP maximum Z scores of lesions were compared between the 2 studies. There were 47 abnormal lesions on BZR images and 60 abnormal lesions on CBF images in the single-isotope study with the conventional camera. Dual-isotope study with the new system showed concordant abnormal findings of 46 of 47 lesions on BZR and 54 of 60 lesions on CBF images with the single-isotope study with the conventional camera. There was high agreement between the 2 studies in both BZR and CBF findings (Cohen κ values = 0.96 for BZR and 0.78 for CBF). In semiquantitative analysis, maximum Z scores of dual-isotope study with the new system strongly correlated with those of single-isotope study with the conventional camera (BZR: r = 0.82, P < 0.05, CBF: r = 0.87, P < 0.05). Our new SPECT system permits dual-isotope study for pixel-by-pixel analysis of CBF and BZR information with the same pathophysiological condition in patients with epilepsy.

  16. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams.

    Science.gov (United States)

    Yang, Aichao; Li, Ping; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-01

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170-206 Hz has 28-188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137-1.43 mW output power corresponding to 0.035-0.36 μW cm(-3) volume power density at 170-206 Hz.

  17. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Aichao; Li, Ping, E-mail: liping@cqu.edu.cn; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng [Research Center of Sensors and Instruments, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2014-06-15

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170–206 Hz has 28–188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137–1.43 mW output power corresponding to 0.035–0.36 μW cm{sup −3} volume power density at 170–206 Hz.

  18. Making the invisible visible: improving conspicuity of noncalcified gallstones using dual-energy CT.

    Science.gov (United States)

    Uyeda, Jennifer W; Richardson, Ian J; Sodickson, Aaron D

    2017-06-28

    To determine whether virtual monochromatic imaging (VMI) increases detectability of noncalcified gallstones on dual-energy CT (DECT) compared with conventional CT imaging. This retrospective IRB-approved, HIPAA-compliant study included consecutive patients who underwent DECT of the abdomen in the Emergency Department during a 30-month period (July 1, 2013-December 31, 2015), with a comparison US or MR within 1-year. 51 patients (36F, 15M; mean age 52 years) fulfilled the inclusion criteria. All DECT were acquired on a dual-source 128 × 2 slice scanner using either 80/Sn140 or 100/Sn140 kVp pairs. Source images at high and low kVp were used for DE post-processing with VMI. Within 3 mm reconstructed images, regions of interest of 0.5 cm(2) were placed on noncalcified gallstones and bile to record hounsfield units (HU) at VMI energy levels ranging between 40 and 190 keV. Noncalcified gallstones uniformly demonstrated lowest HU at 40 keV and increase at higher keV; the HU of bile varied at higher keV. Few of the noncalcified stones are visible at 70 keV (simulating a conventional 120 kVp scan), with measured contrast (bile-stone HU difference) 20 HU in 2%. Contrast was maximal at 40 keV, where 100% demonstrated >20 HU difference from surrounding bile, 75% >44 HU difference, and 50% >60 HU difference. A paired t test demonstrated a significant difference (p < 0.0001) between this stone-bile contrast at 40 vs. 70 keV and 70 vs. 190 keV. Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

  19. Compound analysis of gallstones using dual energy computed tomography-Results in a phantom model

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Ralf W., E-mail: ralfwbauer@aol.co [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Schulz, Julian R., E-mail: julian.schulz@t-online.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Zedler, Barbara, E-mail: zedler@em.uni-frankfurt.d [Department of Forensic Medicine, Clinic of the Goethe University Frankfurt, Kennedyallee 104, 60596 Frankfurt (Germany); Graf, Thomas G., E-mail: thomas.gt.graf@siemens.co [Siemens AG Healthcare Sector, Computed Tomography, Physics and Applications, Siemensstrasse 1, 91313 Forchheim (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)

    2010-07-15

    Purpose: The potential of dual energy computed tomography (DECT) for the analysis of gallstone compounds was investigated. The main goal was to find parameters, that can reliably define high percentage (>70%) cholesterol stones without calcium components. Materials and methods: 35 gallstones were analyzed with DECT using a phantom model. Stone samples were put into specimen containers filled with formalin. Containers were put into a water-filled cylindrical acrylic glass phantom. DECT scans were performed using a tube voltage/current of 140 kV/83 mAs (tube A) and 80 kV/340 mAs (tube B). ROI-measurements to determine CT attenuation of each sector of the stones that had different appearance on the CT images were performed. Finally, semi-quantitative infrared spectroscopy (FTIR) of these sectors was performed for chemical analysis. Results: ROI-measurements were performed in 45 different sectors in 35 gallstones. Sectors containing >70% of cholesterol and no calcium component (n = 20) on FTIR could be identified with 95% sensitivity and 100% specificity on DECT. These sectors showed typical attenuation of -8 {+-} 4 HU at 80 kV and +22 {+-} 3 HU at 140 kV. Even the presence of a small calcium component (<10%) hindered the reliable identification of cholesterol components as such. Conclusion: Dual energy CT allows for reliable identification of gallstones containing a high percentage of cholesterol and no calcium component in this pre-clinical phantom model. Results from in vivo or anthropomorphic phantom trials will have to confirm these results. This may enable the identification of patients eligible for non-surgical treatment options in the future.

  20. Linear modeling of single-shot dual-energy x-ray imaging using a sandwich detector

    Science.gov (United States)

    Kim, J.; Kim, D. W.; Kim, S. H.; Yun, S.; Youn, H.; Jeon, H.; Kim, H. K.

    2017-01-01

    For single-shot dual-energy (DE) imaging, a sandwich detector typically consists of a thin front detector and a thick rear detector. Therefore, the spatial-resolution characteristics of the two detectors are different, and as a result, weighted subtraction of the corresponding two images gives rise to edge-enhancement characteristics in the resulting DE images. This is a unique characteristic of single-shot DE imaging compared to the conventional dual-shot DE imaging which uses the same detector to acquire low- and high-energy images. Using a linear-systems theory, in this paper, we show that the modulation-transfer function (MTF) of a sandwich detector is a weighted average of contributions from each MTF characteristic of two detector layers forming the sandwich detector. The MTF results obtained using the developed model are validated with those measured directly from single-shot DE images for an edge-knife phantom. Weighting larger than at least 0.5 in DE reconstruction gives an enhancement in DE MTF at mid and high spatial frequencies compared to the MTFs obtained from each detector layer. The behavior of the linear model as a function of weighting factor used for DE reconstruction is discussed in comparisons with numerical simulations.

  1. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  2. Energy Saving and Efficient Energy Use By Power Electronic Systems

    DEFF Research Database (Denmark)

    2017-01-01

    , such as in the applications of adjustable speed drives and solid-state lighting systems. Power electronics gives also a high flexibility when renewable power production is introduced to electrical energy systems. Future research opportunities and challenges will finally be discussed.......In the development of the modern society, one of the key factors is to save energy in order to become more independent of other energy resources. Two important approaches can be taken—one is to change behavior and thereby save energy—the second one is to develop new technology which is able to save...... energy in different applications. This chapter will give an overview of challenges and possibilities in terms of energy saving and also energy efficient use. This includes a discussion on high efficiency power electronics devices and the systems they are used for energy loss reduction. The key enabling...

  3. Processing of interlaced images in 4–10 MeV dual energy customs system for material recognition

    Directory of Open Access Journals (Sweden)

    S. Ogorodnikov

    2002-10-01

    Full Text Available The aim of this article is to demonstrate the practical value of radioscopic differentiation of materials in the 1–10 MeV energy range to the work of customs services. The proposed method for achieving singling out and identifying four basic groups of materials according to an atomic number is complex. Atomic numbers are identified using high- and low-energy profiles obtained through the irradiation of materials on an alternate pulse-by-pulse basis. This is done using a bremsstrahlung beam with 8   MeV/4   MeV dual boundary energies and by using scintillating crystals coupled with silicon photodiodes as detecting elements. An image segmentation technique is then used to discern the distribution of an atomic number on any given image. The color visualization of integral absorption and a material’s atomic composition is carried out according to the intensity hue saturation (IHS colorization scheme. The experiments were carried out on a full-scale prototype of an 8 MeV customs inspection system developed by the Efremov Research Institute.

  4. Reconstruction of limited-angle dual-energy CT using mutual learning and cross-estimation (MLCE)

    Science.gov (United States)

    Zhang, Huayu; Xing, Yuxiang

    2016-03-01

    Dual-energy CT (DECT) imaging has gained a lot of attenuation because of its capability to discriminate materials. We proposes a flexible DECT scan strategy which can be realized on a system with general X-ray sources and detectors. In order to lower dose and scanning time, our DECT acquires two projections data sets on two arcs of limited-angular coverage (one for each energy) respectively. Meanwhile, a certain number of rays from two data sets form conjugate sampling pairs. Our reconstruction method for such a DECT scan mainly tackles the consequent limited-angle problem. Using the idea of artificial neural network, we excavate the connection between projections at two different energies by constructing a relationship between the linear attenuation coefficient of the high energy and that of the low one. We use this relationship to cross-estimate missing projections and reconstruct attenuation images from an augmented data set including projections at views covered by itself (projections collected in scanning) and by the other energy (projections estimated) for each energy respectively. Validated by our numerical experiment on a dental phantom with rather complex structures, our DECT is effective in recovering small structures in severe limited-angle situations. This DECT scanning strategy can much broaden DECT design in reality.

  5. Adaptive optics ophthalmologic systems using dual deformable mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S; Olivier, S; Chen, D; Sadda, S; Joeres, S; Zawadzki, R; Werner, J S; Miller, D

    2007-02-01

    Adaptive Optics (AO) have been increasingly combined with a variety of ophthalmic instruments over the last decade to provide cellular-level, in-vivo images of the eye. The use of MEMS deformable mirrors in these instruments has recently been demonstrated to reduce system size and cost while improving performance. However, currently available MEMS mirrors lack the required range of motion for correcting large ocular aberrations, such as defocus and astigmatism. In order to address this problem, we have developed an AO system architecture that uses two deformable mirrors, in a woofer/tweeter arrangement, with a bimorph mirror as the woofer and a MEMS mirror as the tweeter. This setup provides several advantages, including extended aberration correction range, due to the large stroke of the bimorph mirror, high order aberration correction using the MEMS mirror, and additionally, the ability to ''focus'' through the retina. This AO system architecture is currently being used in four instruments, including an Optical Coherence Tomography (OCT) system and a retinal flood-illuminated imaging system at the UC Davis Medical Center, a Scanning Laser Ophthalmoscope (SLO) at the Doheny Eye Institute, and an OCT system at Indiana University. The design, operation and evaluation of this type of AO system architecture will be presented.

  6. Absolute measurement of the effective atomic number and the electron density by using dual-energy CT images

    Science.gov (United States)

    Kim, Dae-Hong; Lee, Won-Hyung; Jeon, Sung-Soo; Kim, Hee-Joung

    2012-12-01

    Material decomposition using dual-energy and material-selective techniques was performed using computed-tomography (CT)-generated reconstructed images. Previous work using the dual-energy method focused on extracting the effective atomic number and the electron density of materials to confirm the dosimetric accuracy in radiation therapy. Dual-energy methods mostly depend on the device generating the X-rays, such as a synchrotron, and on dose verification for radiation treatment planning. Information obtained from CT imaging is important both in diagnosis and in planning radiation therapy. In a clinical setting, CT images are usually displayed as Houndsfield units (HU), which are extracted from the attenuation coefficient of a material. The attenuation coefficient is calculated using the effective atomic number and the electron density of a material; thus, information expressed in HU can be converted into the effective atomic number and the electron density by using the dual-energy equation. This study was performed using realistic Xray spectra to differentiate between the contrast media and plaque in vascular images. Our results suggest that the effective atomic number and electron density are useful in distinguishing between two adjacent materials with similar HUs.

  7. Complex energy system management using optimization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bridgeman, Stuart; Hurdowar-Castro, Diana; Allen, Rick; Olason, Tryggvi; Welt, Francois

    2010-09-15

    Modern energy systems are often very complex with respect to the mix of generation sources, energy storage, transmission, and avenues to market. Historically, power was provided by government organizations to load centers, and pricing was provided in a regulatory manner. In recent years, this process has been displaced by the independent system operator (ISO). This complexity makes the operation of these systems very difficult, since the components of the system are interdependent. Consequently, computer-based large-scale simulation and optimization methods like Decision Support Systems are now being used. This paper discusses the application of a DSS to operations and planning systems.

  8. Converting hazardous organics into clean energy using a solar responsive dual photoelectrode photocatalytic fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianyong; Li, Jinhua, E-mail: lijinhua@sjtu.edu.cn; Chen, Quanpeng; Bai, Jing; Zhou, Baoxue

    2013-11-15

    Highlights: • A dual photoelcetrode PFC for converting hazardous organics into electricity. • The PFC possesses high cell performance operating in various model compounds. • Parameters were studied for optimization of the PFC performance. • Significant removal rate of chroma was observed in azo dyes solutions. -- Abstract: Direct discharging great quantities of organics into water-body not only causes serious environmental pollution but also wastes energy sources. In this paper, a solar responsive dual photoelectrode photocatalytic fuel cell (PFC{sup 2}) based on TiO{sub 2}/Ti photoanode and Cu{sub 2}O/Cu photocathode was designed for hazardous organics treatment with simultaneous electricity generation. Under solar irradiation, the interior bias voltage produced for the Fermi level difference between photoelectrodes drives photoelectrons of TiO{sub 2}/Ti photoanode to combine with photoholes of Cu{sub 2}O/Cu photocathode through external circuit thus generating electricity. In the meantime, organics are decomposed by photoholes remained at TiO{sub 2}/Ti photoanode. By using various hazardous organics including azo dyes as model pollutants, the PFC showed high converting performance of organics into electricity. For example, in 0.05 M phenol solution, a short-circuit current density 0.23 mA cm{sup −2}, open-circuit voltage 0.49 V, maximum power output 0.36 10{sup −4} W cm{sup −2} was achieved. On the other hand, removal rate of chroma reached 67%, 87% and 63% in 8 h for methyl orange, methylene blue, Congo red, respectively.

  9. Liver fat quantification using fast kVp-switching dual energy CT

    Science.gov (United States)

    Kriston, Andras; Mendonça, Paulo; Silva, Alvin; Paden, Robert G.; Pavlicek, William; Sahani, Dushyant; Janos Kis, Benedek; Rusko, Laszlo; Okerlund, Darin; Bhotika, Rahul

    2011-03-01

    Nonalcoholic steatohepatitis (NASH) is a liver disease that occurs in patients that lack a history of the well-proven association of alcohol use. A major symptom of NASH is increased fat deposition in the liver. Gemstone Spectral Imaging (GSI) with fast kVp-switching enables projection-based material decomposition, offering the opportunity to accurately characterize tissue types, e.g., fat and healthy liver tissue, based on their energy-sensitive material attenuation and density. We describe our pilot efforts to apply GSI to locate and quantify the amount of fat deposition in the liver. Two approaches are presented, one that computes percentage fat from the difference in HU values at high and low energies and the second based on directly computing fat volume fraction at each voxel using multi-material decomposition. Simulation software was used to create a phantom with a set of concentric rings, each composed of fat and soft tissue in different relative amounts with attenuation values obtained from the National Institute of Standards and Technology. Monte Carlo 80 and 140 kVp X-ray projections were acquired and CT images of the phantom were reconstructed. Results demonstrated the sensitivity of dual energy CT to the presence of fat and its ability to distinguish fat from soft tissue. Additionally, actual patient (liver) datasets were acquired using GSI and monochromatic images at 70 and 140 keV were reconstructed. Preliminary results demonstrate a tissue sensitivity that appears sufficient to quantify fat content with a degree of accuracy as may be needed for non-invasive clinical assessment of NASH.

  10. Endoleak detection using single-acquisition split-bolus dual-energy computer tomography (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Javor, D.; Wressnegger, A.; Unterhumer, S.; Kollndorfer, K.; Nolz, R.; Beitzke, D.; Loewe, C. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria)

    2017-04-15

    To assess a single-phase, dual-energy computed tomography (DECT) with a split-bolus technique and reconstruction of virtual non-enhanced images for the detection of endoleaks after endovascular aneurysm repair (EVAR). Fifty patients referred for routine follow-up post-EVAR CT and a history of at least one post-EVAR follow-up CT examination using our standard biphasic (arterial and venous phase) routine protocol (which was used as the reference standard) were included in this prospective trial. An in-patient comparison and an analysis of the split-bolus protocol and the previously used double-phase protocol were performed with regard to differences in diagnostic accuracy, radiation dose, and image quality. The analysis showed a significant reduction of radiation dose of up to 42 %, using the single-acquisition split-bolus protocol, while maintaining a comparable diagnostic accuracy (primary endoleak detection rate of 96 %). Image quality between the two protocols was comparable and only slightly inferior for the split-bolus scan (2.5 vs. 2.4). Using the single-acquisition, split-bolus approach allows for a significant dose reduction while maintaining high image quality, resulting in effective endoleak identification. (orig.)

  11. Lung function assessment using Xe-133 dynamic SPECT in dual-camera system

    Energy Technology Data Exchange (ETDEWEB)

    Sakaji, Katsuyuki; Akiyama, Masayuki; Nakazawa, Yasuo [Showa Univ., Tokyo (Japan). Hospital; Umeda, Hirotaka; Takenaka, Haruki; Shinozuka, Akira

    2001-09-01

    The purpose of this study was to estimate lung regional function using Xe-133 dynamic SPECT. SPECT equipment with a dual camera was used. Fourteen rotation acquisitions were obtained beginning immediately after Xe-133 gas inhalation. The time activity curve of each pixel was obtained, and T{sub 1/2} of the washout phase was calculated and mapped. Residual radioactivity was evaluated. Adequate images could be obtained at 30 seconds per rotation even with the dual-camera system. Mapping of T{sub 1/2} allowed temporal changes on one image. Three-dimensional evaluation could be made on a SPECT system using our method. (author)

  12. Feasibility study to demonstrate cardiac imaging using fast kVp switching dual-energy computed tomography: phantom study

    Science.gov (United States)

    Madhav, Priti; Imai, Yasuhiro; Narayanan, Suresh; Dutta, Sandeep; Chandra, Naveen; Hsieh, Jiang

    2012-03-01

    Dual-energy computed tomography is a novel imaging tool that has the potential to reduce beam hardening artifacts and enhance material separation over conventional imaging techniques. Dual-energy acquisitions can be performed by using a fast kVp technology to switch between acquiring adjacent projections at two distinct x-ray spectra (80 and 140 kVp). These datasets can be used to further compute material density and monochromatic images for better material separation and beam hardening reduction by virtue of the projection domain process. The purpose of this study was to evaluate the feasibility of using dual-energy in cardiac imaging for myocardial perfusion detection and coronary artery lumen visualization. Data was acquired on a heart phantom, which consisted of the chambers and aorta filled with Iodine density solution (500 HU @ 120 kVp), a defect region between the aorta and chamber (40 HU @ 120 kVp), two Iodinefilled vessels (400 HU @ 120 kVp) of different diameters with high attenuation (hydroxyapatite) plaques (HAP), and with a 30-cm water equivalent body ring around the phantom. Prospective ECG-gated single-energy and prospective ECG-gated dual-energy imaging was performed. Results showed that the generated monochromatic images had minimal beam hardening artifacts which improved the accuracy and detection of the myocardial defect region. Material density images were useful in differentiating and quantifying the actual size of the plaque and coronary artery lumen. Overall, this study shows that dual-energy cardiac imaging will be a valuable tool for cardiac applications.

  13. Predicting Football Players' Dual-Energy X-Ray Absorptiometry Body Composition Using Standard Anthropometric Measures

    Science.gov (United States)

    Oliver, Jonathan M.; Lambert, Brad S.; Martin, Steven E.; Green, John S.; Crouse, Stephen F.

    2012-01-01

    Context: The recent increase in athlete size, particularly in football athletes of all levels, coupled with the increased health risk associated with obesity warrants continued monitoring of body composition from a health perspective in this population. Equations developed to predict percentage of body fat (%Fat) have been shown to be population specific and might not be accurate for football athletes. Objective: To develop multiple regression equations using standard anthropometric measurements to estimate dual-energy x-ray absorptiometry %Fat (DEXA%Fat) in collegiate football players. Design: Controlled laboratory study. Patients and Other Participants: One hundred fifty-seven National Collegiate Athletic Association Division IA football athletes (age  =  20 ± 1 years, height  =  185.6 ± 6.5 cm, mass  =  103.1 ± 20.4 kg, DEXA%Fat  =  19.5 ± 9.1%) participated. Main Outcome Measure(s): Participants had the following measures: (1) body composition testing with dual-energy x-ray absorptiometry; (2) skinfold measurements in millimeters, including chest, triceps, subscapular, midaxillary, suprailiac, abdominal (SFAB), and thigh; and (3) standard circumference measurements in centimeters, including ankle, calf, thigh, hip (AHIP), waist, umbilical (AUMB), chest, wrist, forearm, arm, and neck. Regression analysis and fit statistics were used to determine the relationship between DEXA%Fat and each skinfold thickness, sum of all skinfold measures (SFSUM), and individual circumference measures. Results: Statistical analysis resulted in the development of 3 equations to predict DEXA%Fat: model 1, (0.178 • AHIP) + (0.097 • AUMB) + (0.089 • SFSUM) − 19.641; model 2, (0.193 • AHIP) + (0.133 • AUMB) + (0.371 • SFAB) − 23.0523; and model 3, (0.132 • SFSUM) + 3.530. The R2 values were 0.94 for model 1, 0.93 for model 2, and 0.91 for model 3 (for all, P < .001). Conclusions: The equations developed provide an accurate way to assess DEXA

  14. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

    Science.gov (United States)

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images

  15. Open cycle cooling systems using solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.; Sovrano, M.

    Open cycle cooling systems are particularly suitable for utilizing solar energy. In all these systems the adsorption and absorption phenomena are very important, hence they are described separately. The cycles used are essentially two: the Baum-Kakabaev cycle using liquid absorbers and the dehumidification/humidification cycle where also adsorbent substances can be utilized. Solar energy is used in the regeneration process of dehumidifying substances. Reactivation modes can be various: suitability of one mode or the other can depend on the climate of the site where the system is installed.

  16. Wool Base determination using dual energy X-ray absorptiometry (DEXA)

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Chris [Institute of Geological and Nuclear Science Ltd., Lower Hutt (New Zealand)]. E-mail: c.kroger@gns.cri.nz; Murray Bartle, C. [Institute of Geological and Nuclear Science Ltd., Lower Hutt (New Zealand); West, John G. [Institute of Geological and Nuclear Science Ltd., Lower Hutt (New Zealand); Rensburg, Brendon van [New Zealand Wool Testing Authority Ltd., Napier (New Zealand)

    2006-12-15

    An industry grade dual energy X-ray absorptiometry (DEXA) scanner was calibrated for Wool Base determination. The calibration used 201 Crossbred and Merino wool samples, and a further 72 samples to validate the calibration. The prediction correlation had the smallest residual standard deviation (RSD) when the independently measured mean fibre diameter (MFD) was included in the multiple regression analysis. Best results were achieved when separate calibrations were used for individual wool breeds. The RSD for the Merino calibration set of 44 samples was 1.88, when the MFD was included in the regression, and 2.1 without. The RSD for 144 Crossbred samples was 1.73 including the MFD, and 2.59 without. The validation trial with 46 Crossbred and 24 Merino wool samples resulted in RSD of 2.35 and 2.23, respectively. An excellent DEXA repeatability was achieved at a standard deviation of {approx}0.2%. Improvement of the calibration is expected from concurrent laboratory testing and scanning. The research shows the promising potential for DEXA as a tool to determine Wool Base.

  17. Characterisation of urinary stones in the presence of iodinated contrast medium using dual-energy CT: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jia; Qu, Mingliang; Duan, Xinhui; Takahashi, Naoki; Kawashima, Akira; Leng, Shuai; McCollough, Cynthia H. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

    2012-12-15

    To develop a dual-energy CT (DECT) method for differentiating uric acid (UA) from non-UA stones in the presence of iodinated contrast medium. Thirty UA and 45 non-UA stones were selected after infra-red spectroscopic analysis and independently placed in a 1.5-ml vial, which was filled first with saline and then with increasing concentrations of iodine. For each condition, tubes were put in a 35-cm water phantom and examined using a dual-source CT system at 100 and 140 kV. Virtual unenhanced images created from CT data sets of the stones in iodine-containing solutions provided position and volume information. This map was used to calculate a CT number ratio to differentiate stone type. A region-growing method was developed to improve the ability to differentiate between UA and non-UA stones with iodinated contrast medium. The sensitivity for detecting UA stones was 100 % for unenhanced images but fell to 18 % with 20 mgI/ml iodine solution and 0 % for higher concentrations. With region growing, the sensitivity for detecting UA stones was increased to 100 %, 82 %, 57 %, 50 % and 21 % for iodine solutions of 20, 40, 60, 80 and 100 mgI/ml. The region-growing method improves differentiation of UA from non-UA stones on contrast-enhanced DECT urograms. (orig.)

  18. Assessment of the effect of oral corticosteroids on bone mineral density in systemic lupus erythematosus: a preliminary study with dual energy x ray absorptiometry.

    OpenAIRE

    1990-01-01

    Dual energy x ray absorptiometry and a wide range of blood and urine tests were used to assess the propensity of patients with systemic lupus erythematosus to develop an impairment of bone mineral density. Surprisingly, in this preliminary study no significant differences in bone mineral density were found when patients taking 10 mg or more of prednisolone for six months or longer were compared with those who had never taken prednisolone.

  19. Assessment of the effect of oral corticosteroids on bone mineral density in systemic lupus erythematosus: a preliminary study with dual energy x ray absorptiometry.

    Science.gov (United States)

    Dhillon, V B; Davies, M C; Hall, M L; Round, J M; Ell, P J; Jacobs, H S; Snaith, M L; Isenberg, D A

    1990-08-01

    Dual energy x ray absorptiometry and a wide range of blood and urine tests were used to assess the propensity of patients with systemic lupus erythematosus to develop an impairment of bone mineral density. Surprisingly, in this preliminary study no significant differences in bone mineral density were found when patients taking 10 mg or more of prednisolone for six months or longer were compared with those who had never taken prednisolone.

  20. PERFORMANCE ANALYSIS OF OSCM TRANSMISSION SYSTEMS BY USING DUAL ELECTRODE MZ-MODULATOR

    Directory of Open Access Journals (Sweden)

    ASHOKA KUMAR RATHA,

    2011-04-01

    Full Text Available In this paper, the performance of OSCM transmission system using dual electrode MZ modulator was analyzed and investigated by simulation through the use of optisim software. The dual electrode z-cut LiNbO3MZM makes the use of two linear polarizer’s placed before and after it respectively. By carefully selecting the angles of the two linear polarizers, the third order intermodulation and harmonic distortion can be suppressed significantly. The performance of the system was investigated by varying few parameters such as data rate, optical modulation index, subcarrier frequency, phase shift difference between branches of dual electrode MZ modulator, fiber length and phase of the local oscillator at the receiver side.

  1. Converting hazardous organics into clean energy using a solar responsive dual photoelectrode photocatalytic fuel cell.

    Science.gov (United States)

    Li, Jianyong; Li, Jinhua; Chen, Quanpeng; Bai, Jing; Zhou, Baoxue

    2013-11-15

    Direct discharging great quantities of organics into water-body not only causes serious environmental pollution but also wastes energy sources. In this paper, a solar responsive dual photoelectrode photocatalytic fuel cell (PFC(2)) based on TiO2/Ti photoanode and Cu2O/Cu photocathode was designed for hazardous organics treatment with simultaneous electricity generation. Under solar irradiation, the interior bias voltage produced for the Fermi level difference between photoelectrodes drives photoelectrons of TiO2/Ti photoanode to combine with photoholes of Cu2O/Cu photocathode through external circuit thus generating electricity. In the meantime, organics are decomposed by photoholes remained at TiO2/Ti photoanode. By using various hazardous organics including azo dyes as model pollutants, the PFC showed high converting performance of organics into electricity. For example, in 0.05 M phenol solution, a short-circuit current density 0.23 mA cm(-2), open-circuit voltage 0.49 V, maximum power output 0.3610(-4)W cm(-2) was achieved. On the other hand, removal rate of chroma reached 67%, 87% and 63% in 8h for methyl orange, methylene blue, Congo red, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Hexavalent chromium reduction and energy recovery by using dual-chambered microbial fuel cell.

    Science.gov (United States)

    Gangadharan, Praveena; Nambi, Indumathi M

    2015-01-01

    Microbial fuel cell (MFC) technology is utilized to treat hexavalent chromium (Cr(VI)) from wastewater and to generate electricity simultaneously. The Cr(VI) is bioelectrochemically reduced to non-toxic Cr(III) form in the presence of an organic electron donor in a dual-chambered MFC. The Cr(VI) as catholyte and artificial wastewater inoculated with anaerobic sludge as anolyte, Cr(VI) at 100 mg/L was completely removed within 48 h (initial pH value 2.0). The total amount of Cr recovered was 99.87% by the precipitation of Cr(III) on the surface of the cathode. In addition to that 78.4% of total organic carbon reduction was achieved at the anode chamber within 13 days of operation. Furthermore, the maximum power density of 767.01 mW/m² (2.08 mA/m²) was achieved by MFCs at ambient conditions. The present work has successfully demonstrated the feasibility of using MFCs for simultaneous energy production from wastewater and reduction of toxic Cr(VI) to non-toxic Cr(III).

  3. Energy storage systems: power grid and energy market use cases

    Directory of Open Access Journals (Sweden)

    Komarnicki Przemysław

    2016-09-01

    Full Text Available Current power grid and market development, characterized by large growth of distributed energy sources in recent years, especially in Europa, are according energy storage systems an increasingly larger field of implementation. Existing storage technologies, e.g. pumped-storage power plants, have to be upgraded and extended by new but not yet commercially viable technologies (e.g. batteries or adiabatic compressed air energy storage that meet expected demands. Optimal sizing of storage systems and technically and economically optimal operating strategies are the major challenges to the integration of such systems in the future smart grid. This paper surveys firstly the literature on the latest niche applications. Then, potential new use case and operating scenarios for energy storage systems in smart grids, which have been field tested, are presented and discussed and subsequently assessed technically and economically.

  4. Three dimensional laser microfabrication in diamond using a dual adaptive optics system.

    Science.gov (United States)

    Simmonds, Richard D; Salter, Patrick S; Jesacher, Alexander; Booth, Martin J

    2011-11-21

    Femtosecond laser fabrication of controlled three dimensional structures deep in the bulk of diamond is facilitated by a dual adaptive optics system. A deformable mirror is used in parallel with a liquid crystal spatial light modulator to compensate the extreme aberrations caused by the refractive index mismatch between the diamond and the objective immersion medium. It is shown that aberration compensation is essential for the generation of controlled micron-scale features at depths greater than 200 μm, and the dual adaptive optics approach demonstrates increased fabrication efficiency relative to experiments using a single adaptive element.

  5. A Novel Dual-input Isolated Current-Fed DC-DC Converter for Renewable Energy System

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2010-01-01

    In this paper, a novel isolated current-fed DC-DC converter (boost-type) with two input power sources based on multi-transformer structure, which is suitable for fuel cells and super-capacitors hybrid energy system, is proposed and designed. With particular transformer windings connection strategy......, the proposed converter can draw power from two different DC sources with lower voltage and deliver it to the higher voltage DC bus or load individually and simultaneously. The detailed operation principle of the proposed converter has been analyzed in dual-input mode and single-input mode, respectively...

  6. Use of dual-energy X-ray absorptiometry in obese individuals.

    Science.gov (United States)

    Tataranni, P A; Ravussin, E

    1995-10-01

    Dual-energy X-ray absorptiometry (DXA) provides precise measurements of body composition in humans. Because its use in obese subjects is limited by the size of the scanning area, we explored the possibility of estimating whole-body composition from DXA half-body scans. Body composition of 183 subjects with a wide range of body sizes [body mass index (BMI; in kg/m2) of 17.7 - 52.8] was assessed by DXA and hydrodensitometry. Subjects fitting in the DXA scanning area (group A, n = 156) were scanned once whereas subjects exceeding it (group B, n = 27) were scanned twice, once for each side of the body. When body-composition results for the right and left sides were compared, only minimal differences between the two sides of the body were found in both groups. Least-squares-regression analysis of whole-body composition by hydrodensitometry on DXA gave the following results: percent body fat, r2 = 0.89 (SEE = 4.1%); fat-free mass, r2 = 0.89 (SEE = 3.72 kg); and fat mass, r2 = 0.95 (SEE = 3.57 kg). Similar r2 values and SEEs were obtained for percent body fat when only results from DXA half-body scans of all subjects were considered: right side, r2 = 0.90 (SEE = 4.1%); and left side, r2 = 0.89 (SEE = 4.2%). The error in predicting body composition by hydrodensitometry from DXA whole- or half-body scans was not affected by the subject's body size and/or scanning technique. In conclusion, our results indicate that half-body scan values by DXA accurately predict whole-body composition.

  7. Evaluation of useful treatment which uses dual-energy when curing lung-cancer patient with stereotactic body radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hyeong Jun; Lee, Yeong Gyu; Kim, Yeong Jae; Park, Yeong Gyu [Dept. of Radiation Oncology, Catholic University Seoul St Mary' s hospital, Seoul (Korea, Republic of)

    2016-12-15

    This study will evaluate the clinical utility by applying clinical schematic that uses monoenergy or dual energy as according to the location of tumors to the stereotactic radiotherapy to compare the change in actual dose given to the real tumor and the dose that locates adjacent to the tumor. CT images from a total of 10 patients were obtained and the clinical planning were planned based on the volumetric modulated arc therapy on monoenergy and dual energy. To analyze the change factor in the tumor, Conformity Index(CI) and Homogeneity Index(HI) and maximum dose quantity were each calculated and comparing the dose distribution on normal tissues, v{sub 10} and v{sub 5}, first ⁓ fourth ribs closest to the tumor (1st ⁓ 4th Rib), Spinal Cord, Esophagus and Trachea were selected. Also, in order to confirm the accuracy on which the planned dose distribution is really measured, the 2-dimensional ion chamber array was used to measure the dose distribution. As of the tumor factor, CI and HI showed a number close to 1 when the two energies were used. As of the maximum dose, the front chest wall showed 2% and the dorsal tumor showed equivalent value. As of normal tissue, the front chest wall tumors were reduced by 4%, 5% when both energies were used in the adjacent rib and as of trachea, reduced by 11%, 17%. As of the dose in the lung, as of v{sub 10}, it reduced by 1.5%, v{sub 5} by 1%. As of the rear chest wall, when both energies were used, the ribs adjacent to the tumors showed 6%, 1%, 4%, 12% reduction, and in the lung dose distribution, v{sub 10} reduced by 3%, and v{sub 5} reduced by 3.1%. The dose measurement in all energies were in accordance to the results of Gamma Index 3mm/3%. Conclusion : It is considered that rather than using monoenergy, utilizing double energy in the clinical setting can be more effectively applied to the superficial tumors.

  8. First experience with single-source dual-energy computed tomography in six patients with acute arthralgia: a feasibility experiment using joint aspiration as a reference

    Energy Technology Data Exchange (ETDEWEB)

    Diekhoff, Torsten; Kiefer, Tobias; Hamm, Bernd; Hermann, Kay-Geert A. [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Berlin (Germany); Ziegeler, Katharina; Feist, Eugen [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Rheumatology and Clinical Immunology, Berlin (Germany); Mews, Juergen [Toshiba Medical Systems Europe, BV, Zoetermeer (Netherlands)

    2015-11-15

    Dual-energy computed tomography (DECT) is an emerging imaging technique for examining patients with suspected gout. Single-source dual-energy CT (S-DECT) is a new way of obtaining DECT information on conventional CT scanners rather than using special dual-source CT systems. We tested the feasibility of S-DECT (320-row CT; Aquilion ONE, Toshiba Medical Systems, Otawara, Japan) in 6 patients (5 men, 1 woman; mean age 61.3, range 48 to 69 years) with acute arthralgia and suspected gout, and compared the S-DECT findings with the results of joint aspiration. Three patients had a diagnosis of gouty arthritis with negatively birefringent crystals in synovial fluid, in addition to gouty tophi in S-DECT. Three patients had no detectable crystals by polarization microscopy and no tophi on DECT. Their final diagnoses were rheumatoid arthritis, activated osteoarthritis, and septic arthritis in one case each. This initial experience suggests that S-DECT might be a valuable alternative to dual-source CT. Hence, more patients may benefit from its additional diagnostic abilities in the future. (orig.)

  9. Development of Dual Power Multirotor System

    Directory of Open Access Journals (Sweden)

    Chin E. Lin

    2017-01-01

    Full Text Available Vertical take-off and landing (VTOL aircraft has good flight characteristics and system performance without runway. The multirotor system has been tried to expand into larger size for longer endurance or higher payload. But the motor power to endurance ratio has been limited. Due to the specific energy of gasoline being much higher than battery, introducing gasoline engine into multirotor system can be considered. This paper proposes a dual power multirotor system to combine a quadrotor using gasoline engines to provide major lift in shorter arm with another quadrotor using brushless DC motors to offer most controllable force with longer arm. System design, fabrication, and verification of the proposed dual power multirotor system development are presented. Preliminary flights have achieved 16 kg payload for long endurance flight. This is useful for various applications with advanced improvements.

  10. Dual energy CT: New horizon in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  11. Dual-Energy CT: New Horizon in Medical Imaging.

    Science.gov (United States)

    Goo, Hyun Woo; Goo, Jin Mo

    2017-01-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  12. SU-E-T-493: Accelerated Monte Carlo Methods for Photon Dosimetry Using a Dual-GPU System and CUDA.

    Science.gov (United States)

    Liu, T; Ding, A; Xu, X

    2012-06-01

    To develop a Graphics Processing Unit (GPU) based Monte Carlo (MC) code that accelerates dose calculations on a dual-GPU system. We simulated a clinical case of prostate cancer treatment. A voxelized abdomen phantom derived from 120 CT slices was used containing 218×126×60 voxels, and a GE LightSpeed 16-MDCT scanner was modeled. A CPU version of the MC code was first developed in C++ and tested on Intel Xeon X5660 2.8GHz CPU, then it was translated into GPU version using CUDA C 4.1 and run on a dual Tesla m(2) 090 GPU system. The code was featured with automatic assignment of simulation task to multiple GPUs, as well as accurate calculation of energy- and material- dependent cross-sections. Double-precision floating point format was used for accuracy. Doses to the rectum, prostate, bladder and femoral heads were calculated. When running on a single GPU, the MC GPU code was found to be ×19 times faster than the CPU code and ×42 times faster than MCNPX. These speedup factors were doubled on the dual-GPU system. The dose Result was benchmarked against MCNPX and a maximum difference of 1% was observed when the relative error is kept below 0.1%. A GPU-based MC code was developed for dose calculations using detailed patient and CT scanner models. Efficiency and accuracy were both guaranteed in this code. Scalability of the code was confirmed on the dual-GPU system. © 2012 American Association of Physicists in Medicine.

  13. Monopolar radiofrequency ablation using a dual-switching system and a separable clustered electrode: Evaluation of the in vivo efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jeong Hee; Lee, Jeong Min; Hwang, Eui Jin; Hwang, In Pyung; Beak, Jee Hyun; Han, Joon Koo; Choi, Byung Ihn [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-04-15

    To determine the in vivo efficiency of monopolar radiofrequency ablation (RFA) using a dual-switching (DS) system and a separable clustered (SC) electrode to create coagulation in swine liver. Thirty-three ablation zones were created in nine pigs using a DS system and an SC electrode in the switching monopolar mode. The pigs were divided into two groups for two experiments: 1) preliminary experiments (n = 3) to identify the optimal inter-electrode distances (IEDs) for dual-switching monopolar (DSM)-RFA, and 2) main experiments (n = 6) to compare the in vivo efficiency of DSM-RFA with that of a single-switching monopolar (SSM)-RFA. RF energy was alternatively applied to one of the three electrodes (SSM-RFA) or concurrently applied to a pair of electrodes (DSM-RFA) for 12 minutes in in vivo porcine livers. The delivered RFA energy and the shapes and dimensions of the coagulation areas were compared between the two groups. No pig died during RFA. The ideal IEDs for creating round or oval coagulation area using the DSM-RFA were 2.0 and 2.5 cm. DSM-RFA allowed more efficient RF energy delivery than SSM-RFA at the given time (23.0 ± 4.0 kcal vs. 16.92 ± 2.0 kcal, respectively; p 0.0005). DSM-RFA created a significantly larger coagulation volume than SSM-RFA (40.4 ± 16.4 cm{sup 3} vs. 20.8 ± 10.7 cm{sup 3}; p < 0.001). Both groups showed similar circularity of the ablation zones (p = 0.29). Dual-switching monopolar-radiofrequency ablation using an SC electrode is feasible and can create larger ablation zones than SSM-RFA as it allows more RF energy delivery at a given time.

  14. Dual-path handheld system for cornea and retina imaging using optical coherence tomography

    Science.gov (United States)

    Shirazi, Muhammad Faizan; Wijesinghe, Ruchire Eranga; Ravichandran, Naresh Kumar; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

    2016-11-01

    A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images simultaneously. Both eyes of a person can be imaged at the same time to obtain the images of the cornea of one eye and the retina of the other eye. Cornea, retina, and optic disc images are acquired with the proposed sample arm. Experimental results demonstrate the usefulness of this system for imaging of different eye segments. This system reduces the time required for imaging of the two eyes and is cost effective.

  15. Fundamental evaluation of bone densitometry using dual energy X-ray absorptiometry (DEXA)

    Energy Technology Data Exchange (ETDEWEB)

    Koizumi, Kiyoshi; Uchiyama, Guio; Araki, Tsutomu (Yamanashi Medical Coll., Tamaho (Japan)) (and others)

    1990-02-01

    A newly developed instrument based on dual energy X-ray absorptiometry (DEXA), Hologic QDR-1000, was evaluated fundamentally and clinically. Image quality was quite satisfactory though radiation exposure was minimal, 780.2 nC/kg (3.024 mR) for lumbar measurement. Reproducibility of the repeated measurement of a phantom was fairly good; 0.343 CV% in a same day and 0.520 CV% in a long period. Accuracy determined by measurement of potassium phosphate solution was also satisfactory. Bone mineral densities measured by this instrument were fairly correlated with those measured by single energy quantitative CT; coefficient was 0.740 for 17 patients. Mix-DP plates of more than 10 cm thick overestimated the bone mineral densities of a phantom. Bone mineral densities of Japanese normal volunteers were in the normal range (mean {plus minus} 2SD) of the Americans though mostly lower than the mean. In patients with spondylosis deformans or prominent aortic calcification, bone mineral densities might be overestimated. Lateral view was obtainable though its reproducibility was not good. Positioning especially for measuring femoral neck was quite critical for reproducible measurement. In conclusion, this new instrument is quite accurate and satisfactory for clinical application to measuring bone mineral densities. (author).

  16. Pulmonary embolism detection using localized vessel-based features in dual energy CT

    Science.gov (United States)

    Dicente Cid, Yashin; Depeursinge, Adrien; Foncubierta Rodríguez, Antonio; Platon, Alexandra; Poletti, Pierre-Alexandre; Müller, Henning

    2015-03-01

    Pulmonary embolism (PE) affects up to 600,000 patients and contributes to at least 100,000 deaths every year in the United States alone. Diagnosis of PE can be difficult as most symptoms are unspecific and early diagnosis is essential for successful treatment. Computed Tomography (CT) images can show morphological anomalies that suggest the existence of PE. Various image-based procedures have been proposed for improving computer-aided diagnosis of PE. We propose a novel method for detecting PE based on localized vessel-based features computed in Dual Energy CT (DECT) images. DECT provides 4D data indexed by the three spatial coordinates and the energy level. The proposed features encode the variation of the Hounsfield Units across the different levels and the CT attenuation related to the amount of iodine contrast in each vessel. A local classification of the vessels is obtained through the classification of these features. Moreover, the localization of the vessel in the lung provides better comparison between patients. Results show that the simple features designed are able to classify pulmonary embolism patients with an AUC (area under the receiver operating curve) of 0.71 on a lobe basis. Prior segmentation of the lung lobes is not necessary because an automatic atlas-based segmentation obtains similar AUC levels (0.65) for the same dataset. The automatic atlas reaches 0.80 AUC in a larger dataset with more control cases.

  17. Phantom-less bone mineral density (BMD) measurement using dual energy computed tomography-based 3-material decomposition

    Science.gov (United States)

    Hofmann, Philipp; Sedlmair, Martin; Krauss, Bernhard; Wichmann, Julian L.; Bauer, Ralf W.; Flohr, Thomas G.; Mahnken, Andreas H.

    2016-03-01

    Osteoporosis is a degenerative bone disease usually diagnosed at the manifestation of fragility fractures, which severely endanger the health of especially the elderly. To ensure timely therapeutic countermeasures, noninvasive and widely applicable diagnostic methods are required. Currently the primary quantifiable indicator for bone stability, bone mineral density (BMD), is obtained either by DEXA (Dual-energy X-ray absorptiometry) or qCT (quantitative CT). Both have respective advantages and disadvantages, with DEXA being considered as gold standard. For timely diagnosis of osteoporosis, another CT-based method is presented. A Dual Energy CT reconstruction workflow is being developed to evaluate BMD by evaluating lumbar spine (L1-L4) DE-CT images. The workflow is ROI-based and automated for practical use. A dual energy 3-material decomposition algorithm is used to differentiate bone from soft tissue and fat attenuation. The algorithm uses material attenuation coefficients on different beam energy levels. The bone fraction of the three different tissues is used to calculate the amount of hydroxylapatite in the trabecular bone of the corpus vertebrae inside a predefined ROI. Calibrations have been performed to obtain volumetric bone mineral density (vBMD) without having to add a calibration phantom or to use special scan protocols or hardware. Accuracy and precision are dependent on image noise and comparable to qCT images. Clinical indications are in accordance with the DEXA gold standard. The decomposition-based workflow shows bone degradation effects normally not visible on standard CT images which would induce errors in normal qCT results.

  18. Detection of sulfur in the reinforced concrete structures using a dual pulsed LIBS system

    Science.gov (United States)

    Gondal, M. A.; Dastageer, A.; Maslehuddin, M.; Alnehmi, A. J.; Al-Amoudi, O. S. B.

    2012-04-01

    In concrete structures, an excessive amount of sulfate ions can cause severe damage to the strength and the stability of the building structures and hence a sensitive and reliable technique for sulfate ion detection in concrete is highly desirable. Laser-induced breakdown spectroscopy (LIBS) is one of the most reliable and sensitive techniques to identify the presence of potentially dangerous sulfur in the concrete structure. The atomic emission lines of sulfur lying in the 200-900 nm region are mostly singly ionized states and hence inherently very weak. In order to enhance the sensitivity of the conventional LIBS system, we employed a dual pulsed LIBS system for detection of weak spectral line of sulfur in concrete using the S II peak at 545.38 nm as a marker for quantifying sulfur content in the concrete. The 1064 nm fundamental and 266 nm fourth harmonic of the Nd:YAG laser in conjunction with Spectrograph/gated ICCD camera are the core factors in improvement of sensitivity. Furthermore, the dual pulsed LIBS system and the fine maneuvering of the gate parameters and interpulse delay yielded improvement in the sensitivity, and resulted in a systematic correlation of the LIBS signal with the concentration of sulfur in the concrete sample. In order to quantify the sulfur content in concrete, a calibration curve was also drawn by recording the LIBS spectra of sample having sulfur in various concentrations. The limit of detection achieved with our dual pulsed LIBS system is approximately 38 μg/g.

  19. Analysis of a generalized dual reflector antenna system using physical optics

    Science.gov (United States)

    Acosta, Roberto J.; Lagin, Alan R.

    1992-01-01

    Reflector antennas are widely used in communication satellite systems because they provide high gain at low cost. Offset-fed single paraboloids and dual reflector offset Cassegrain and Gregorian antennas with multiple focal region feeds provide a simple, blockage-free means of forming multiple, shaped, and isolated beams with low sidelobes. Such antennas are applicable to communications satellite frequency reuse systems and earth stations requiring access to several satellites. While the single offset paraboloid has been the most extensively used configuration for the satellite multiple-beam antenna, the trend toward large apertures requiring minimum scanned beam degradation over the field of view 18 degrees for full earth coverage from geostationary orbit may lead to impractically long focal length and large feed arrays. Dual reflector antennas offer packaging advantages and more degrees of design freedom to improve beam scanning and cross-polarization properties. The Cassegrain and Gregorian antennas are the most commonly used dual reflector antennas. A computer program for calculating the secondary pattern and directivity of a generalized dual reflector antenna system was developed and implemented at LeRC. The theoretical foundation for this program is based on the use of physical optics methodology for describing the induced currents on the sub-reflector and main reflector. The resulting induced currents on the main reflector are integrated to obtain the antenna far-zone electric fields. The computer program is verified with other physical optics programs and with measured antenna patterns. The comparison shows good agreement in far-field sidelobe reproduction and directivity.

  20. Impact of an advanced image-based monoenergetic reconstruction algorithm on coronary stent visualization using third generation dual-source dual-energy CT: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Cannao, Paola M. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Milan, Scuola di Specializzazione in Radiodiagnostica, Milan (Italy); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Fuller, Stephen R.; Varga-Szemes, Akos [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Muscogiuri, Giuseppe; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-06-15

    To evaluate the impact of an advanced monoenergetic (ME) reconstruction algorithm on CT coronary stent imaging in a phantom model. Three stents with lumen diameters of 2.25, 3.0 and 3.5 mm were examined with a third-generation dual-source dual-energy CT (DECT). Tube potential was set at 90/Sn150 kV for DE and 70, 90 or 120 kV for single-energy (SE) acquisitions and advanced modelled iterative reconstruction was used. Overall, 23 reconstructions were evaluated for each stent including three SE acquisitions and ten advanced and standard ME images with virtual photon energies from 40 to 130 keV, respectively. In-stent luminal diameter was measured and compared to nominal lumen diameter to determine stent lumen visibility. Contrast-to-noise ratio was calculated. Advanced ME reconstructions substantially increased lumen visibility in comparison to SE for stents ≤3 mm. 130 keV images produced the best mean lumen visibility: 86 % for the 2.25 mm stent (82 % for standard ME and 64 % for SE) and 82 % for the 3.0 mm stent (77 % for standard ME and 69 % for SE). Mean DLP for SE 120 kV and DE acquisitions were 114.4 ± 9.8 and 58.9 ± 2.2 mGy x cm, respectively. DECT with advanced ME reconstructions improves the in-lumen visibility of small stents in comparison with standard ME and SE imaging. (orig.)

  1. Economic Evaluation of Dual-Level-Residence Solar-Energy System

    Science.gov (United States)

    1982-01-01

    105-page report is one in a series of economic evaluations of different solar-energy installations. Using study results, an optimal collector area is chosen that minimizes life-cycle costs. From this optimal size thermal and economic performance is evaluated.

  2. Output regulation for linear singular systems using dual-observer based compensators

    Science.gov (United States)

    Deutscher, Joachim

    2013-05-01

    In this article, the output regulation problem is solved for singular systems by using dual observer-based compensators. This has the advantage that output regulation can be achieved under weak conditions. Namely, different from previous approaches, an implementable compensator can be directly determined in form of a classical state space model without a transformation into Weierstrass-Kronecker canonical form. Furthermore, the impulse controllability and observability of the singular system is not required and the output to be controlled needs not be measurable. The results of the article are demonstrated by means of a simple mechanical system.

  3. In vivo characterization of tumor vasculature using iodine and gold nanoparticles and dual energy micro-CT.

    Science.gov (United States)

    Clark, Darin P; Ghaghada, Ketan; Moding, Everett J; Kirsch, David G; Badea, Cristian T

    2013-03-21

    Tumor blood volume and vascular permeability are well established indicators of tumor angiogenesis and important predictors in cancer diagnosis, planning and treatment. In this work, we establish a novel preclinical imaging protocol which allows quantitative measurement of both metrics simultaneously. First, gold nanoparticles are injected and allowed to extravasate into the tumor, and then liposomal iodine nanoparticles are injected. Combining a previously optimized dual energy micro-CT scan using high-flux polychromatic x-ray sources (energies: 40 kVp, 80 kVp) with a novel post-reconstruction spectral filtration scheme, we are able to decompose the results into 3D iodine and gold maps, allowing simultaneous measurement of extravasated gold and intravascular iodine concentrations. Using a digital resolution phantom, the mean limits of detectability (mean CNR = 5) for each element are determined to be 2.3 mg mL(-1) (18 mM) for iodine and 1.0 mg mL(-1) (5.1 mM) for gold, well within the observed in vivo concentrations of each element (I: 0-24 mg mL(-1), Au: 0-9 mg mL(-1)) and a factor of 10 improvement over the limits without post-reconstruction spectral filtration. Using a calibration phantom, these limits are validated and an optimal sensitivity matrix for performing decomposition using our micro-CT system is derived. Finally, using a primary mouse model of soft-tissue sarcoma, we demonstrate the in vivo application of the protocol to measure fractional blood volume and vascular permeability over the course of five days of active tumor growth.

  4. In vivo characterization of tumor vasculature using iodine and gold nanoparticles and dual energy micro-CT

    Science.gov (United States)

    Clark, Darin P.; Ghaghada, Ketan; Moding, Everett J.; Kirsch, David G.; Badea, Cristian T.

    2013-03-01

    Tumor blood volume and vascular permeability are well established indicators of tumor angiogenesis and important predictors in cancer diagnosis, planning and treatment. In this work, we establish a novel preclinical imaging protocol which allows quantitative measurement of both metrics simultaneously. First, gold nanoparticles are injected and allowed to extravasate into the tumor, and then liposomal iodine nanoparticles are injected. Combining a previously optimized dual energy micro-CT scan using high-flux polychromatic x-ray sources (energies: 40 kVp, 80 kVp) with a novel post-reconstruction spectral filtration scheme, we are able to decompose the results into 3D iodine and gold maps, allowing simultaneous measurement of extravasated gold and intravascular iodine concentrations. Using a digital resolution phantom, the mean limits of detectability (mean CNR = 5) for each element are determined to be 2.3 mg mL-1 (18 mM) for iodine and 1.0 mg mL-1 (5.1 mM) for gold, well within the observed in vivo concentrations of each element (I: 0-24 mg mL-1, Au: 0-9 mg mL-1) and a factor of 10 improvement over the limits without post-reconstruction spectral filtration. Using a calibration phantom, these limits are validated and an optimal sensitivity matrix for performing decomposition using our micro-CT system is derived. Finally, using a primary mouse model of soft-tissue sarcoma, we demonstrate the in vivo application of the protocol to measure fractional blood volume and vascular permeability over the course of five days of active tumor growth.

  5. A Novel Dual-input Isolated Current-Fed DC-DC Converter for Renewable Energy System

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2010-01-01

    In this paper, a novel isolated current-fed DC-DC converter (boost-type) with two input power sources based on multi-transformer structure, which is suitable for fuel cells and super-capacitors hybrid energy system, is proposed and designed. With particular transformer windings connection strategy......, the proposed converter can draw power from two different DC sources with lower voltage and deliver it to the higher voltage DC bus or load individually and simultaneously. The detailed operation principle of the proposed converter has been analyzed in dual-input mode and single-input mode, respectively....... Furthermore, the method to increase the number of input ports, the magnetic integration structure, and ground loop decoupling are discussed. Experimental results from the lab prototype converter with two DC voltage sources verify the validity of the theoretical analysis and design of the converter....

  6. Detection of parathyroid adenomas using a monophasic dual-energy computed tomography acquisition: diagnostic performance and potential radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Leiva-Salinas, Carlos; Flors, Lucia; Durst, Christopher R.; Hou, Qinghua; Mukherjee, Sugoto [University of Virginia, Department of Radiology, Division of Neuroradiology, Charlottesville, VA (United States); Patrie, James T. [University of Virginia, Department of Public Health Sciences, Charlottesville, VA (United States); Wintermark, Max [Stanford University, Department of Radiology, Palo Alto, CA (United States)

    2016-11-15

    The aims of the study were to compare the diagnostic performance of a combination of virtual non-contrast (VNC) images and arterial images obtained from a single-phase dual-energy CT (DECT) acquisition and standard non-contrast and arterial images from a biphasic protocol and to study the potential radiation dose reduction of the former approach. All DECT examinations performed for evaluation of parathyroid adenomas during a 13-month period were retrospectively reviewed. An initial single-energy unenhanced acquisition was followed by a dual-energy arterial phase acquisition. ''Virtual non-contrast images'' were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated three different sets of images during three reading sessions: single arterial phase, single-phase DECT (virtual non-contrast and arterial phase), and standard biphasic protocol (true non-contrast and arterial phase). The accuracy of interpretation in lateralizing an adenoma to the side of the neck and localizing it to a quadrant in the neck was evaluated. Sixty patients (mean age, 65.5 years; age range, 38-87 years) were included in the study. The lateralization and localization accuracy, sensitivity, and positive predicted value (PPV) and negative predicted value (NPV) of the different image datasets were comparable. The combination of VNC and arterial images was more specific than arterial images alone to lateralize a parathyroid lesion (OR = 1.93, p = 0.043). The use of the single-phase protocol resulted in a calculated radiation exposure reduction of 52.8 %. Virtual non-contrast and arterial images from a single DECT acquisition showed similar diagnostic accuracy than a biphasic protocol, providing a significant dose reduction. (orig.)

  7. Unconditional security of time-energy entanglement quantum key distribution using dual-basis interferometry.

    Science.gov (United States)

    Zhang, Zheshen; Mower, Jacob; Englund, Dirk; Wong, Franco N C; Shapiro, Jeffrey H

    2014-03-28

    High-dimensional quantum key distribution (HDQKD) offers the possibility of high secure-key rate with high photon-information efficiency. We consider HDQKD based on the time-energy entanglement produced by spontaneous parametric down-conversion and show that it is secure against collective attacks. Its security rests upon visibility data-obtained from Franson and conjugate-Franson interferometers-that probe photon-pair frequency correlations and arrival-time correlations. From these measurements, an upper bound can be established on the eavesdropper's Holevo information by translating the Gaussian-state security analysis for continuous-variable quantum key distribution so that it applies to our protocol. We show that visibility data from just the Franson interferometer provides a weaker, but nonetheless useful, secure-key rate lower bound. To handle multiple-pair emissions, we incorporate the decoy-state approach into our protocol. Our results show that over a 200-km transmission distance in optical fiber, time-energy entanglement HDQKD could permit a 700-bit/sec secure-key rate and a photon information efficiency of 2 secure-key bits per photon coincidence in the key-generation phase using receivers with a 15% system efficiency.

  8. Added value of lung perfused blood volume images using dual-energy CT for assessment of acute pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Munemasa, E-mail: radokada@yamaguchi-u.ac.jp [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Kunihiro, Yoshie [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Nakashima, Yoshiteru [Department of Radiology, Yamaguchi Grand Medical Center, Oosaki 77, Hofu, Yamaguchi 747-8511 (Japan); Nomura, Takafumi [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Kudomi, Shohei; Yonezawa, Teppei [Department of Radiology, Yamaguchi University Hospital, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Suga, Kazuyoshi [Department of Radiology, St. Hills Hospital, Imamurakita 3-7-18, Ube, Yamaguchi 755-0155 (Japan); Matsunaga, Naofumi [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan)

    2015-01-15

    Purpose: To investigate the added value of lung perfused blood volume (LPBV) using dual-energy CT for the evaluation of intrapulmonary clot (IPC) in patients suspected of having acute pulmonary embolism (PE). Materials and methods: Institutional review board approval was obtained for this retrospective study. Eighty-three patients suspected of having PE who underwent CT pulmonary angiography (CTPA) using a dual-energy technique were enrolled in this study. Two radiologists who were blinded retrospectively and independently reviewed CTPA images alone and the combined images with color-coded LPBV over a 4-week interval, and two separate sessions were performed with a one-month interval. Inter- and intraobserver variability and diagnostic accuracy were evaluated for each reviewer with receiver operating characteristic (ROC) curve analysis. Results: Values for inter- and intraobserver agreement, respectively, were better for CTPA combined with LPBV (ICC = 0.847 and 0.937) than CTPA alone (ICC = 0.748 and 0.861). For both readers, diagnostic accuracy (area under the ROC curve [A{sub z}]) were also superior, when CTPA alone (A{sub z} = 0.888 [reader 1] and 0.912 [reader 2]) was compared with that after the combination with LPBV images (A{sub z} = 0.966 [reader 1] and 0.959 [reader 2]) (p < 0.001). However, A{sub z} values of both images might not have significant difference in statistics, because A{sub z} value of CTPA alone was high and 95% confidence intervals overlapped in both images. Conclusion: Addition of dual-energy perfusion CT to CTPA improves detection of peripheral IPCs with better interobserver agreement.

  9. Accuracy analysis of intrahepatic fat density measurements using dual-energy computed tomography: Validation using a test phantom.

    Science.gov (United States)

    Arai, Tomohiro; Misawa, Masaki; Arai, Miki; Shinozaki, Masafumi; Sakamoto, Kayo; Yajima, Yoshinobu; Nozaki, Yuichi; Tajima, Tsuyoshi; Sato, Masanori; Hinoshita, Fumihiko

    2017-01-01

    Currently, no standardized method for measuring intrahepatic fat density via conventional computed tomography (CT) exists. We aim to quantify intrahepatic fat density via material decomposition analysis using rapid kilovolt peak-switching dual-energy (RSDE) CT. Homogenized porcine liver and fat (lard) were mixed in various ratios to produce phantoms for fat density verification. The actual fat density was measured on the basis of the phantom volume and weight, and these measurements were used as reference densities. The fat and liver mass attenuation coefficients, which were used as the material basis pairs, were employed in the material decomposition analysis. Then, the measured fat density of each phantom was compared with the reference densities. For fat content differences exceeding 2%, the measured fat density for the phantoms became statistically significant (p densities and RSDE-measured fat densities was reasonably high (R > 0.9997); this indicates the validity of this analysis method. Intrahepatic fat density can be measured using the mass attenuation coefficients of fat and liver in a material decomposition analysis. Given the knowledge of the accuracy and the limitations found in this study, our method can quantitatively evaluate fat density.

  10. A Dual Function Energy Store

    Directory of Open Access Journals (Sweden)

    Ron Tolmie

    2014-11-01

    Full Text Available Heat can be collected from local energy sources and concentrated into a relatively small volume, and at a useful working temperature, by using a heat pump as the concentrator. That heat can be stored and utilized at a later date for applications like space heating. The process is doing two things at the same time: storing heat and shifting the power demand. The concentration step can be done at night when there is normally a surplus of power and its timing can be directly controlled by the power grid operator to ensure that the power consumption occurs only when adequate power is available. The sources of heat can be the summer air, the heat extracted from buildings by their cooling systems, natural heat from the ground or solar heat, all of which are free, abundant and readily accessible. Such systems can meet the thermal needs of buildings while at the same time stabilizing the grid power demand, thus reducing the need for using fossil-fuelled peaking power generators. The heat pump maintains the temperature of the periphery at the ambient ground temperature so very little energy is lost during storage.

  11. Sequential concentration of bacteria and viruses from marine waters using a dual membrane system.

    Science.gov (United States)

    Abdelzaher, A M; Solo-Gabriele, H M; Wright, M E; Palmer, C J

    2008-01-01

    The ability to rapidly and effectively concentrate diverse microbes is an essential component for monitoring water quality at recreational beaches. The purpose of this study was to develop a 0.45 microm pore size dual membrane system, which can sequentially concentrate both viruses and bacteria. The top PVDF membrane was used to filter bacteria by physical straining while the bottom HA membrane retained viruses through adsorption. The recovery of this system was assessed using test organisms: enterococci and somatic coliphage. Volumes of 100 to 400 mL of unspiked and sewage-spiked beach water were filtered through both types of membranes. The PVDF membrane recovered statistically equivalent amounts of enterococci when compared to traditional membranes. All of the coliphage passed through the PVDF membrane, while 22% passed through the HA membrane. Increasing the volume from 100 to 400 mL did not significantly influence recoveries. Up to 35% of coliphage was eluted from the bottom membrane using beef extract solution. Rinsing bottom membranes with 0.5 mmol L(-1) H(2)S0(4) was found to deactivate somatic coliphage. This research demonstrates the potential of using a dual membrane adsorption system for the concentration of both bacteria and viruses from recreational beaches. A proposed bi-layer filtration system can be designed for simultaneous bacteria and virus filtration. Future experiments should focus on measurements utilizing additional bacteria and viruses.

  12. 基于同步辐射光源的双能CT成像方法%Dual-energy CT imaging method using synchrotron radiation

    Institute of Scientific and Technical Information of China (English)

    郝佳; 张丽; 邢宇翔; 康克军

    2011-01-01

    The distribution of electron density can be obtained by dual-energy imaging technology with high precision,which is important for medical diagnosis and treatment planning in the radiotherapy.A dual-energy CT imaging method was developed using synchrotron radiation to improve the reconstruction,with the interference light post-processing algorithm analyzed for reconstruction.Numerical simulations with different materials were implemented using the post-processing reconstruction method to show that the electron density and effective atomic number can be obtained with high precision,with much less error than that of conventional dual-energy CT system using Bremsstrahlung radiation.The results also show that dual-energy X-ray CT using synchrotron radiation has the potential to be an important tool for quantitative measurement in biological research.China has developed a third-generation synchrotron radiation light source in Shanghai,which provides an excellent scientific platform for the further research of dual-energy CT imaging.%双能X射线CT成像技术可以精确地获得被扫描物体中的电子密度分布,对于医疗诊断和癌症放射治疗具有重要的参考价值。为了提高双能CT重建精度,该文提出了一种基于同步辐射光源的双能CT成像方法,并对相干光的后处理重建算法进行了研究。同步辐射光源具有一系列的优势。使用不同物质进行双能CT成像数值模拟可以发现:采用同步辐射光源进行双能CT重建,可以更加精确地获取被扫描物质的等效原子序数及电子密度,误差远小于使用X光机的传统双能CT系统。结果表明,基于同步辐射光源的双能CT成像技术将成为生物医学中定量研究的重要手段。目

  13. A new method to measure electron density and effective atomic number using dual-energy CT images

    Science.gov (United States)

    Ramos Garcia, Luis Isaac; Pérez Azorin, José Fernando; Almansa, Julio F.

    2016-01-01

    The purpose of this work is to present a new method to extract the electron density ({ρ\\text{e}} ) and the effective atomic number (Z eff) from dual-energy CT images, based on a Karhunen-Loeve expansion (KLE) of the atomic cross section per electron. This method was used to calibrate a Siemens Definition CT using the CIRS phantom. The predicted electron density and effective atomic number using 80 kVp and 140 kVp were compared with a calibration phantom and an independent set of samples. The mean absolute deviations between the theoretical and calculated values for all the samples were 1.7 %  ±  0.1 % for {ρ\\text{e}} and 4.1 %  ±  0.3 % for Z eff. Finally, these results were compared with other stoichiometric method. The application of the KLE to represent the atomic cross section per electron is a promising method for calculating {ρ\\text{e}} and Z eff using dual-energy CT images.

  14. Process for whole cell saccharification of lignocelluloses to sugars using a dual bioreactor system

    Science.gov (United States)

    Lu, Jue; Okeke, Benedict

    2012-03-27

    The present invention describes a process for saccharification of lignocelluloses to sugars using whole microbial cells, which are enriched from cultures inoculated with paper mill waste water, wood processing waste and soil. A three-member bacterial consortium is selected as a potent microbial inocula and immobilized on inedible plant fibers for biomass saccharification. The present invention further relates the design of a dual bioreactor system, with various biocarriers for enzyme immobilization and repeated use. Sugars are continuously removed eliminating end-product inhibition and consumption by cell.

  15. Myocardial perfusion imaging with dual energy CT.

    Science.gov (United States)

    Jin, Kwang Nam; De Cecco, Carlo N; Caruso, Damiano; Tesche, Christian; Spandorfer, Adam; Varga-Szemes, Akos; Schoepf, U Joseph

    2016-10-01

    Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  16. Identification of Dual-Rate Sampled Hammerstein Systems with a Piecewise-Linear Nonlinearity Using the Key Variable Separation Technique

    Directory of Open Access Journals (Sweden)

    Ying-Ying Wang

    2015-06-01

    Full Text Available The identification difficulties for a dual-rate Hammerstein system lie in two aspects. First, the identification model of the system contains the products of the parameters of the nonlinear block and the linear block, and a standard least squares method cannot be directly applied to the model; second, the traditional single-rate discrete-time Hammerstein model cannot be used as the identification model for the dual-rate sampled system. In order to solve these problems, by combining the polynomial transformation technique with the key variable separation technique, this paper converts the Hammerstein system into a dual-rate linear regression model about all parameters (linear-in-parameter model and proposes a recursive least squares algorithm to estimate the parameters of the dual-rate system. The simulation results verify the effectiveness of the proposed algorithm.

  17. In vivo cell kinetics of the bone marrow transplantation using dual colored transgenic rat system

    Science.gov (United States)

    Kai, Kotaro; Teraoka, Satoshi; Adachi, Yasushi; Ikehara, Susumu; Murakami, Takashi; Kobayashi, Eiji

    2008-02-01

    Because bone marrow is an adequate site for bone marrow stem cells, intra-bone marrow - bone marrow transplantation (IBM-BMT) is an efficient strategy for bone marrow transplantation (BMT). However, the fate of the transplanted cells remains unclear. Herein, we established a dual-colored transgenic rat system utilizing green fluorescent protein (GFP) and a luciferase (luc) marker. We then utilized this system to investigate the in vivo kinetics of transplanted bone marrow cells (BMCs) after authentic intravenous (IV)-BMT or IBM-BMT. The in vivo fate of the transplanted cells was tracked using an in vivo luminescent imaging technique; alterations in peripheral blood chimerism were also followed using flow cytometry. IBM-BMT and IV-BMT were performed using syngeneic and allogeneic rat combinations. While no difference in the proliferation pattern was observed between the two treatment groups at 7 days after BMT, different distribution patterns were clearly observed during the early phase. In the IBM-BMT-treated rats, the transplanted BMCs were engrafted immediately at the site of the injected bone marrow and expanded more rapidly than in the IV-BMT-treated rats during this phase. Graft-versus-host disease was also visualized. Our bio-imaging system using dual-colored transgenic rats is a powerful tool for performing quantitative and morphological assessments in vivo.

  18. TU-A-12A-08: Computing Longitudinal Material Changes in Bone Metastases Using Dual Energy Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schmidtlein, CR; Hwang, S; Veeraraghavan, H; Fehr, D; Humm, J; Deasy, J [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2014-06-15

    Purpose: This study demonstrates a methodology for tracking changes in metastatic bone disease using trajectories in material basis space in serial dual energy computed tomography (DECT) studies. Methods: This study includes patients with bone metastases from breast cancer that had clinical surveillance CT scans using a General Electric CT750HD in dual energy mode. A radiologist defined regions-of-interested (ROI) for bone metastasis, normal bone, and marrow across the serial DECT scans. Our approach employs a Radon transform to forward-projection the basis images, namely, water and iodine, into sinogram space. This data is then repartitioned into fat/bone and effective density/Z image pairs using assumed energy spectrums for the x-ray energies. This approach both helps remove negative material densities and avoids adding spectrum-hardening artifacts. These new basis data sets were then reconstructed via filtered back-projection to create new material basis pair images. The trajectories of these pairs were then plotted in the new basis space providing a means to both visualize and quantitatively measure changes in the material properties of the tumors. Results: ROI containing radiologist defined metastatic bone disease showed well-defined trajectories in both fat/bone and effective density/Z space. ROI that contained radiologist defined normal bone and marrow did not exhibit any discernible trajectories and were stable from scan to scan. Conclusions: The preliminary results show that changes in material composition and effective density/Z image pairs were seen primarily in metastasis and not in normal tissue. This study indicates that by using routine clinical DECT it may be possible to monitor therapy response of bone metastases because healing or worsening bone metastases change material composition of bone. Additional studies are needed to further validate these results and to test for their correlation with outcome.

  19. Development of dual-source hybrid heat pump system using groundwater and air

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Yujin; Ooka, Ryozo [Cw403 Institute of Industry Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Shiba, Yoshiro [Zeneral Heatpump Industry Co., Ltd., Nagoya 459-8001 (Japan)

    2010-06-15

    To achieve high heat pump efficiency, groundwater heat pump (GWHP) system uses groundwater, which is relatively stable AT temperature compared with outdoor air, as a heat source. However, it is difficult to meet annual heating and cooling loads using only groundwater as a heat source. In order to optimize the operation method of GWHP systems, it is necessary to develop a system utilizing both groundwater and air sources according to the building load conditions. Furthermore, during intermediate seasons (such as spring and autumn) with reduced heating and cooling loads, GWHP system is less efficient than air source heat pump (ASHP) system according to temperature conditions. In order to more efficiently use GWHP systems, it is necessary to develop a system which utilizes both groundwater and air sources according to temperature conditions and building loads. This research has developed a GWHP system that employs a hybrid heat pump system with groundwater wells using dual groundwater and air heat sources. In this paper, the annual performance of the developed system has been calculated, and several case studies have been conducted on the effect of introduction location, refrigerant and pumping rate. Furthermore, the coefficient of system performance and the effects on underground environments have been evaluated by real-scale experiment using two wells. (author)

  20. SU-E-J-59: Feasibility of Markerless Tumor Tracking by Sequential Dual-Energy Fluoroscopy On a Clinical Tumor Tracking System

    Energy Technology Data Exchange (ETDEWEB)

    Dhont, J; Poels, K; Verellen, D; Tournel, K; Gevaert, T; Steenbeke, F; Burghelea, M; De Ridder, M [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Brussels (Belgium)

    2015-06-15

    Purpose: To evaluate the feasibility of markerless tumor tracking through the implementation of a novel dual-energy imaging approach into the clinical dynamic tracking (DT) workflow of the Vero SBRT system. Methods: Two sequential 20 s (11 Hz) fluoroscopy sequences were acquired at the start of one fraction for 7 patients treated for primary and metastatic lung cancer with DT on the Vero system. Sequences were acquired using 2 on-board kV imaging systems located at ±45° from the MV beam axis, at respectively 60 kVp (3.2 mAs) and 120 kVp (2.0 mAs). Offline, a normalized cross-correlation algorithm was applied to match the high (HE) and low energy (LE) images. Per breathing phase (inhale, exhale, maximum inhale and maximum exhale), the 5 best-matching HE and LE couples were extracted for DE subtraction. A contrast analysis according to gross tumor volume was conducted based on contrast-to-noise ratio (CNR). Improved tumor visibility was quantified using an improvement ratio. Results: Using the implanted fiducial as a benchmark, HE-LE sequence matching was effective for 13 out of 14 imaging angles. Overlying bony anatomy was removed on all DE images. With the exception of two imaging angles, the DE images showed no significantly improved tumor visibility compared to HE images, with an improvement ratio averaged over all patients of 1.46 ± 1.64. Qualitatively, it was observed that for those imaging angles that showed no significantly improved CNR, the tumor tissue could not be reliably visualized on neither HE nor DE images due to a total or partial overlap with other soft tissue. Conclusion: Dual-energy subtraction imaging by sequential orthogonal fluoroscopy was shown feasible by implementing an additional LE fluoroscopy sequence. However, for most imaging angles, DE images did not provide improved tumor visibility over single-energy images. Optimizing imaging angles is likely to improve tumor visibility and the efficacy of dual-energy imaging. This work was in

  1. Energy Systems Analysis of Waste to Energy Technologies by use of EnergyPLAN

    DEFF Research Database (Denmark)

    Münster, Marie

    recommended to support research into gasification of waste without the addition of coal and biomass. Together, the two solutions may contribute to an alternate use of one third of the waste which is currently incinerated. The remaining fractions should still be incinerated with priority given to combined heat......Even when policies of waste prevention, re-use and recycling are prioritised, a fraction of waste will still be left which can be used for energy recovery. This report asks the question: How to utilise waste for energy in the best way seen from an energy system perspective? Eight different Waste......-to-Energy technologies are compared with a focus on fuel efficiency, CO2 reductions and costs. The comparison is made by conducting detailed energy system analyses of the present system as well as a potential future Danish energy system with a large share of combined heat and power and wind power. The study shows...

  2. Simultaneous dual-energy X-ray stereo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mokso, Rajmund, E-mail: rajmund.mokso@psi.ch [Paul Scherrer Institute, Swiss Light Source, CH 5232 Villigen (Switzerland); Oberta, Peter [Institute of Physics of the Academy of Sciences of the Czech Republic, v.v.i., Na Slovance 1999/2, Praha 8 (Czech Republic); Rigaku Innovative Technologies Europe s.r.o., Novodvorska 994, Praha 4 (Czech Republic)

    2015-06-26

    A Laue–Bragg geometry is introduced for splitting an X-ray beam and tuning each of the two branches to selected wavelength. Stereoscopic and dual-energy imaging was performed with this system. Dual-energy or K-edge imaging is used to enhance contrast between two or more materials in an object and is routinely realised by acquiring two separate X-ray images each at different X-ray wavelength. On a broadband synchrotron source an imaging system to acquire the two images simultaneously was realised. The single-shot approach allows dual-energy and stereo imaging to be applied to dynamic systems. Using a Laue–Bragg crystal splitting scheme, the X-ray beam was split into two and the two beam branches could be easily tuned to either the same or to two different wavelengths. Due to the crystals’ mutual position, the two beam branches intercept each other under a non-zero angle and create a stereoscopic setup.

  3. Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups.

    Science.gov (United States)

    Liu, Chien-Hung; Yeh, Shien-Chang; Huang, Hsueh-Liang

    2010-02-01

    A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 microm, and the uncertainty is estimated to be +/-1.37 microm for the measured thickness of 150 microm.

  4. A Low Cost Automated Monitoring System for Landslides Using Dual Frequency GPS

    Science.gov (United States)

    Mills, H.; Edwards, S.

    2006-12-01

    Landslides are an existing and permanent threat to societies across the globe, generating financial and human losses whenever and wherever they occur. Drawing together the strands of science that provide increased understanding of landslide triggers through accurate modelling is therefore vital for the development of mitigation and management strategies. Together with climatic and geomorphological data a key input here is information on the precise location and timing of landslide events. However, the detailed monitoring of landslides and precursor movements is generally limited to episodic campaigns where limiting factors include equipment and mobilisation costs, time constraints and spatial resolution. This research has developed a geodetic tool of benefit to scientists involved in the development of closely coupled models that seek to explain trigger mechanisms such as rainfall duration and intensity and changes in groundwater pressure to actual real land movements. A fully automated low cost dual frequency GPS station for the continuous in-situ monitoring of landslide sites has been developed. System configuration combines a dual frequency GPS receiver, PC board with a GPRS modem and power supply to deliver 24hr/365day operation capability. Individual components have been chosen to provide the highest accuracies while minimising power consumption resulting in a system around half that of equivalent commercial systems. Measurement point-costs can be further reduced through the use of antenna switching and multi antenna arrays. Continuous data is delivered via mobile phone uplink and processed automatically using geodetic software. The developed system has been extensively tested on a purpose built platform capable of simulating ground movements. Co-mounted antennas have allowed direct comparisons with more expensive geodetic GPS receivers. The system is capable of delivering precise 3D coordinates with a 9 mm rms. The system can be up-scaled resulting in the

  5. Ventilation imaging of the paranasal sinuses using xenon-enhanced dynamic single-energy CT and dual-energy CT: a feasibility study in a nasal cast.

    Science.gov (United States)

    Thieme, Sven F; Möller, Winfried; Becker, Sven; Schuschnig, Uwe; Eickelberg, Oliver; Helck, Andreas D; Reiser, Maximilian F; Johnson, Thorsten R C

    2012-10-01

    To show the feasibility of dual-energy CT (DECT) and dynamic CT for ventilation imaging of the paranasal sinuses in a nasal cast. In a first trial, xenon gas was administered to a nasal cast with a laminar flow of 7 L/min. Dynamic CT acquisitions of the nasal cavity and the sinuses were performed. This procedure was repeated with pulsating xenon flow. Local xenon concentrations in the different compartments of the model were determined on the basis of the enhancement levels. In a second trial, DECT measurements were performed both during laminar and pulsating xenon administration and the xenon concentrations were quantified directly. Neither with dynamic CT nor DECT could xenon-related enhancement be detected in the sinuses during laminar airflow. Using pulsating flow, dynamic imaging showed a xenon wash-in and wash-out in the sinuses that followed a mono-exponential function with time constants of a few seconds. Accordingly, DECT revealed xenon enhancement in the sinuses only after pulsating xenon administration. The feasibility of xenon-enhanced DECT for ventilation imaging was proven in a nasal cast. The superiority of pulsating gas flow for the administration of gas or aerosolised drugs to the paranasal sinuses was demonstrated. • Ventilation of the paranasal sinuses is poorly understood. • Dual-energy CT ventilation imaging has been explored using phantom simulation. • Xenon can be seen in the paranasal sinuses using pulsating xenon flow. • Dual-energy CT uses a lower radiation dose compared with dynamic ventilation CT.

  6. New Low Cost Structure for Dual Axis Mount Solar Tracking System Using Adaptive Solar Sensor

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Ritchie, Ewen; Leban, Krisztina Monika

    2010-01-01

    A solar tracking system is designed to optimize the operation of solar energy receivers. The objective of this paper is proposing a new tracking system structure with two axis. The success strategy of this new project focuses on the economical analysis of solar energy. Therefore it is important...... to determine the most cost effective design, to consider the costs of production and maintenance, and operating. The proposed tracking system uses a new solar sensor position with an adaptive feature....

  7. Structural parameter based modification of energy conscious ESPAR antenna system through optimization for WLAN’s dual-band operability

    CSIR Research Space (South Africa)

    Bembe, MJ

    2010-11-01

    Full Text Available single device. In this study the focus is on the modification of the antenna designs for dual-band functionality which is limited on the ESPAR antenna’s structural parameter. This modification should result in an antenna system which operates in both 2...

  8. Three-Dimensional Reconstruction of Nuclear Envelope Architecture Using Dual-Color Metal-Induced Energy Transfer Imaging.

    Science.gov (United States)

    Chizhik, Anna M; Ruhlandt, Daja; Pfaff, Janine; Karedla, Narain; Chizhik, Alexey I; Gregor, Ingo; Kehlenbach, Ralph H; Enderlein, Jörg

    2017-09-20

    The nuclear envelope, comprising the inner and the outer nuclear membrane, separates the nucleus from the cytoplasm and plays a key role in cellular functions. Nuclear pore complexes (NPCs), which are embedded in the nuclear envelope, control transport of macromolecules between the two compartments. Here, using dual-color metal-induced energy transfer (MIET), we determine the axial distance between Lap2β and Nup358 as markers for the inner nuclear membrane and the cytoplasmic side of the NPC, respectively. Using MIET imaging, we reconstruct the 3D profile of the nuclear envelope over the whole basal area, with an axial resolution of a few nanometers. This result demonstrates that optical microscopy can achieve nanometer axial resolution in biological samples and without recourse to complex interferometric approaches.

  9. Volumetric evaluation of dual-energy perfusion CT by the presence of intrapulmonary clots using a 64-slice dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Munemasa; Nakashima, Yoshiteru; Kunihiro, Yoshie; Nakao, Sei; Matsunaga, Naofumi [Dept. of Radiology, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan)], e-mail: radokada@yamaguchi-u.ac.jp; Morikage, Noriyasu [Medical Bioregulation Dept. of Organ Regulatory Surgery, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan); Sano, Yuichi [Dept. of Radiology, Yamaguchi Univ. Hospital, Yamaguchi (Japan); Suga, Kazuyoshi [Dept. of Radiology, St Hills Hospital, Yamaguchi (Japan)

    2013-07-15

    Background: Dual-energy perfusion CT (DE{sub p}CT) directly represents the iodine distribution in lung parenchyma and low perfusion areas caused by intrapulmonary clots (IPCs) are visualized as low attenuation areas. Purpose: To evaluate if volumetric evaluation of DE{sub p}CT can be used as a predictor of right heart strain by the presence of IPCs. Material and Methods: One hundred and ninety-six patients suspected of having acute pulmonary embolism (PE) underwent DE{sub p}CT using a 64-slice dual-source CT. DE{sub p}CT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V{sub 120}), 1-15 HU (V{sub 15}), 1-10 HU (V{sub 10}), and 1-5 HU (V{sub 5}). Each relative ratio per V{sub 120} was expressed as the %V{sub 15}, %V{sub 10}, and %V{sub 5}. Volumetric data-sets were compared with D-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio, PA diameter, and PA/aorta (PA/Ao) diameter ratio. The areas under the ROC curves (AUCs) were examined for their relationship to the presence of IPCs. This study was approved by the local ethics committee. Results: PA pressure and D-dimer were significantly higher in the patients who had IPCs. In the patients with IPCs, V{sub 15}, V{sub 10}, V{sub 5}, %V{sub 15}, %V{sub 10}, and %V{sub 5} were also significantly higher than those without IPC (P = 0.001). %V{sub 5} had a better correlation with D-dimer (r = 0.30, P < 0.001) and RV/LV diameter ratio (r = 0.27, P < 0.001), and showed a higher AUC (0.73) than the other CT measurements. Conclusion: The volumetric evaluation by DE{sub p}CT had a correlation with D-dimer and RV/LV diameter ratio, and the relative ratio of volumetric CT measurements with a lower attenuation threshold might be recommended for the analysis of acute PE.

  10. On-site analysis of modified surface using dual beam system

    Energy Technology Data Exchange (ETDEWEB)

    Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Goppelt-Langer, P.; Gan Mingle; Zeng Jianer; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Recent results obtained using a dual ion beam system at JAERI/Takasaki are reported. In this system, both of ion implantation and ion beam analysis can be made alternatively or simultaneously at low temperatures. In sapphire implanted with {sup 51}V{sup +} ions, the amorphization process is analyzed referring to the <0001> aligned spectra taken at different temperatures. The discussion is made on the defect profiles different from the simple accumulation of standard Gaussian form. The depth showing the maximum damage at the initial stage of implantation is quite shallow compared with those reported before. The thermal annealing behaviors of lattice damage and the implanted V atoms are also different between the samples implanted at low and room temperatures. In the former one fine particles of vanadium oxide are formed coherently with the easy recovery in high dose sample but in the latter the mixed oxide alloy is formed. (author)

  11. Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

    Science.gov (United States)

    Paziresh, M.; Kingston, A. M.; Latham, S. J.; Fullagar, W. K.; Myers, G. M.

    2016-06-01

    Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073-2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127-135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260-1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and

  12. Estimating breast thickness for dual-energy subtraction in contrast-enhanced digital mammography using calibration phantoms

    Science.gov (United States)

    Lau, Kristen C.; Kwon, Young Joon; Aziz, Moez Karim; Acciavatti, Raymond J.; Maidment, Andrew D. A.

    2016-04-01

    Dual-energy contrast-enhanced digital mammography (DE CE-DM) uses an iodinated contrast agent to image the perfusion and vasculature of the breast. DE images are obtained by a weighted logarithmic subtraction of the high-energy (HE) and low-energy (LE) image pairs. We hypothesized that the optimal DE subtraction weighting factor is thickness-dependent, and developed a method for determining breast tissue composition and thickness in DE CE-DM. Phantoms were constructed using uniform blocks of 100% glandular-equivalent and 100% adipose-equivalent material. The thickness of the phantoms ranged from 3 to 8 cm, in 1 cm increments. For a given thickness, the glandular-adipose composition of the phantom was varied using different combinations of blocks. The logarithmic LE and logarithmic HE signal intensities were measured; they decrease linearly with increasing glandularity for a given thickness. The signals decrease with increasing phantom thickness and the x-ray signal decreases linearly with thickness for a given glandularity. As the thickness increases, the attenuation difference per additional glandular block decreases, indicating beam hardening. From the calibration mapping, we have demonstrated that we can predict percent glandular tissue and thickness when given two distinct signal intensities. Our results facilitate the subtraction of tissue at the boundaries of the breast, and aid in discriminating between contrast agent uptake in glandular tissue and subtraction artifacts.

  13. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Seco, Joao; Sørensen, Thomas Sangild

    2015-01-01

    Background. Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in...

  14. Using Hounsfield Units to Assess Osteoporotic Status on Wrist Computed Tomography Scans: Comparison With Dual Energy X-Ray Absorptiometry.

    Science.gov (United States)

    Johnson, Christine C; Gausden, Elizabeth B; Weiland, Andrew J; Lane, Joseph M; Schreiber, Joseph J

    2016-07-01

    Rates of evaluation and treatment for osteoporosis following distal radius fragility fractures remain low. As a subset of patients with these fractures undergo diagnostic computed tomography (CT) scan of the wrist, utilizing bone mineral density (BMD) measurements available with this imaging can be used to detect osteopenia or osteoporosis. This information may consequently prompt intervention to prevent a subsequent fracture. The purpose of this study was to determine if Hounsfield unit (HU) measurements at the wrist correlate with BMD measurements of the hip, femoral neck, and lumbar spine and to assess the ability of these HU measurements to detect osteoporosis of the hip. Forty-five female patients with distal radius fractures who underwent CT scan and dual energy x-ray absorptiometry scan as part of the management of their wrist fracture were identified. Bone mineral density measurements were made using the regional cancellous bone HU value at the capitate and compared with values obtained by a dual energy x-ray absorptiometry scan. Hounsfield unit values at the capitate were significantly correlated with BMD and t scores at the femoral neck, hip, and lumbar spine. An HU threshold of 307 in the capitate optimized sensitivity (86%) and specificity (94%) for detecting osteoporotic patients. By demonstrating that capitate HU measurements from clinical CT scans are correlated with BMD and t scores at the hip, femoral neck, and lumbar spine, our data suggest that clinical CT scans should have a role in detecting osteopenia and osteoporosis. Diagnostic III. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  15. Anatomical decomposition in dual energy chest digital tomosynthesis

    Science.gov (United States)

    Lee, Donghoon; Kim, Ye-seul; Choi, Sunghoon; Lee, Haenghwa; Choi, Seungyeon; Kim, Hee-Joung

    2016-03-01

    Lung cancer is the leading cause of cancer death worldwide and the early diagnosis of lung cancer has recently become more important. For early screening lung cancer, computed tomography (CT) has been used as a gold standard for early diagnosis of lung cancer [1]. The major advantage of CT is that it is not susceptible to the problem of misdiagnosis caused by anatomical overlapping while CT has extremely high radiation dose and cost compared to chest radiography. Chest digital tomosynthesis (CDT) is a recently introduced new modality for lung cancer screening with relatively low radiation dose compared to CT [2] and also showing high sensitivity and specificity to prevent anatomical overlapping occurred in chest radiography. Dual energy material decomposition method has been proposed for better detection of pulmonary nodules as means of reducing the anatomical noise [3]. In this study, possibility of material decomposition in CDT was tested by simulation study and actual experiment using prototype CDT. Furthermore organ absorbed dose and effective dose were compared with single energy CDT. The Gate v6 (Geant4 application for tomographic emission), and TASMIP (Tungsten anode spectral model using the interpolating polynomial) code were used for simulation study and simulated cylinder shape phantom consisted of 4 inner beads which were filled with spine, rib, muscle and lung equivalent materials. The patient dose was estimated by PCXMC 1.5 Monte Carlo simulation tool [4]. The tomosynthesis scan was performed with a linear movement and 21 projection images were obtained over 30 degree of angular range with 1.5° degree of angular interval. The proto type CDT system has same geometry with simulation study and composed of E7869X (Toshiba, Japan) x-ray tube and FDX3543RPW (Toshiba, Japan) detector. The result images showed that reconstructed with dual energy clearly visualize lung filed by removing unnecessary bony structure. Furthermore, dual energy CDT could enhance

  16. Simultaneous detection and subtyping of porcine endogenous retroviruses proviral DNA using the dual priming oligonucleotide system.

    Science.gov (United States)

    Moon, Hyoung Joon; Park, Seong Jun; Kim, Hye Kwon; Ann, Soo Kyung; Rho, Semi; Keum, Hyun Ok; Park, Bong Kyun

    2010-09-01

    The purpose of this study was to develop a multiplex PCR that can detect porcine endogenous retrovirus (PERV) proviral genes (pol, envA, envB, envC) and porcine mitochondrial DNA, using a dual priming oligonucleotide (DPO) system. The primer specifically detected the PERV proviral genes pol, envA, envB, envC, and porcine mitochondrial DNA only in samples of pig origin. The sensitivity of the primer was demonstrated by simultaneous amplification of all 5 target genes in as little as 10 pg of pig DNA containing PERV proviral genes and mitochondrial DNA. The multiplex PCR, when applied to field samples, simultaneously and successfully amplified PERV proviral genes from liver, blood and hair root samples. Thus, the multiplex PCR developed in the current study using DPO-based primers is a rapid, sensitive and specific assay for the detection and subtyping of PERV proviral genes.

  17. Development of Dual Power Multirotor System

    National Research Council Canada - National Science Library

    2017-01-01

    .... This paper proposes a dual power multirotor system to combine a quadrotor using gasoline engines to provide major lift in shorter arm with another quadrotor using brushless DC motors to offer most...

  18. Energy systems analysis of waste to energy technologies by use of EnergyPLAN

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, M.

    2009-04-15

    Even when policies of waste prevention, re-use and recycling are prioritised, a fraction of waste will still be left which can be used for energy recovery. This report asks the question: How to utilise waste for energy in the best way seen from an energy system perspective? Eight different Waste-to-Energy technologies are compared with a focus on fuel efficiency, CO{sub 2} reductions and costs. The comparison is made by conducting detailed energy system analyses of the present system as well as a potential future Danish energy system with a large share of combined heat and power and wind power. The study shows the potential of using waste for the production of transport fuels such as upgraded biogas and petrol made from syngas. Biogas and thermal gasification technologies are interesting alternatives to waste incineration and it is recommended to support the use of biogas based on manure and organic waste. It is also recommended to support research into gasification of waste without the addition of coal and biomass. Together, the two solutions may contribute to an alternate use of one third of the waste which is currently incinerated. The remaining fractions should still be incinerated with priority given to combined heat and power plants with high electrical efficiencies. (author)

  19. Detection and characterization of crystal suspensions using single-source dual-energy computed tomography: a phantom model of crystal arthropathies.

    Science.gov (United States)

    Diekhoff, Torsten; Kiefer, Tobias; Stroux, Andrea; Pilhofer, Irid; Juran, Ralf; Mews, Jürgen; Blobel, Jörg; Tsuyuki, Masaharu; Ackermann, Beate; Hamm, Bernd; Hermann, Kay-Geert A

    2015-04-01

    The aim of this study was to perform phantom measurements to prove the feasibility of single-source dual-energy computed tomography (DECT) of the extremities using a volume scan mode. In addition, we, for the first time, wanted to determine which concentrations of monosodium urate (MSU) in gout and calcium pyrophosphate (CP) in pseudogout are needed to detect or distinguish these soft tissue depositions with DECT. We created a hand-shaped plastic phantom assembled with a descending order of concentrations of MSU (6.25%-50%) and CP (1.56%-50%) with similar attenuation in conventional computed tomographic (CT) images. Dual-energy imaging was done on a standard 320-row CT scanner with acquisition of 2 volumes: one at 80 and the other at 135 kV. Using linear regression analysis, dual-energy gradients were calculated for MSU and CP. Thereafter, we selected a specific region of interest on the dual-energy graph to color-code MSU and CP on the images. Three blinded readers scored 10 scans of the randomly equipped phantom, corresponding to 60 samples, to determine the sensitivity and specificity of this technique. Receiver operating characteristics analysis was done to determine the diagnostic power. We found a dual-energy gradient for MSU of 1.020 ± 0.006 and for CP of 0.673 ± 0.001. Assessment of the randomized phantom scans indicates reliable detection of MSU at concentrations of 12.5 % or higher and that of CP at 6.25 % or higher, corresponding to deposits with mean Hounsfield unit values of 59.8 for MSU and 101.1 for CP. The sensitivity for MSU ranged from 83.3% to 97.3% at 15/90 mA (135/80 kV) and from 86.7% to 97.3% at 100/570 mA. Specificity was 96.7% to 100% in 15/90 mA and 100% in 100/570 mA of scans. However, there was inferior sensitivity for CP owing to lower concentrations. In the receiver operating characteristics analysis, the area under the curve for MSU ranged from 0.867 to 0.947 at 15/90 mA and from 0.867 to 0.919 at 100/570 mA and that for CP from 0

  20. Xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans: correlation of xenon and CT density values with pulmonary function test results

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo; Yang, Dong Hyun; Seo, Joon Beom; Chae, Eun Jin; Lee, Jeongjin [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Songpa-gu, Seoul (Korea); Hong, Soo-Jong; Yu, Jinho; Kim, Byoung-Ju [University of Ulsan College of Medicine, Department of Pediatrics, Asan Medical Center, Seoul (Korea); Krauss, Bernhard [Siemens Medical Solutions AG-Computed Tomography, Forchheim (Germany)

    2010-09-15

    Xenon ventilation CT using dual-source and dual-energy technique is a recently introduced, promising functional lung imaging method. To expand its clinical applications evidence of additional diagnostic value of xenon ventilation CT over conventional chest CT is required. To evaluate the usefulness of xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans (BO). Seventeen children (age 7-18 years; 11 boys) with BO underwent xenon ventilation CT using dual-source and dual-energy technique. Xenon and CT density values were measured in normal and hyperlucent lung regions on CT and were compared between the two regions. Volumes of hyperlucent regions and ventilation defects were calculated with thresholds determined by visual and histogram-based analysis. Indexed volumes of hyperlucent lung regions and ventilation defects were correlated with pulmonary function test results. Effective doses of xenon CT were calculated. Xenon (14.6 {+-} 6.4 HU vs 26.1 {+-} 6.5 HU; P < 0.001) and CT density (-892.8 {+-} 25.4 HU vs -812.3 {+-} 38.7 HU; P < 0.001) values were significantly lower in hyperlucent regions than in normal lung regions. Xenon and CT density values showed significant positive correlation for the entire lung in 16 children ({gamma} = 0.55 {+-} 0.17, P < 0.001 or =0.017) and for hyperlucent regions in 13 children ({gamma} = 0.44 {+-} 0.16, P < 0.001 or =0.001-0.019). Indexed volumes and volume percentages of hyperlucent lung regions and ventilation defects showed strong negative correlations with forced expiratory volume [FEV1, ({gamma} = -0.64-0.85, P {<=} 0.006)], FEV1/forced vital capacity [FVC, ({gamma} = -0.63-0.84, P {<=} 0.008)], and forced midexpiratory flow rate [FEF{sub 25-75}, ({gamma} = -0.68-0.88, P {<=} 0.002). Volume percentages of xenon ventilation defects (35.0 {+-} 16.4%)] were not significantly different from those of hyperlucent lung regions (38.2 {+-} 18.6%). However, mismatches between the

  1. Split-bolus CT-urography using dual-energy CT: Feasibility, image quality and dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Mitsuru, E-mail: m2rbimn@gmail.com [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Kawai, Tatsuya; Ito, Masato; Ogawa, Masaki [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Ohashi, Kazuya [Nagoya City University Hospital, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Hara, Masaki; Shibamoto, Yuta [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan)

    2012-11-15

    Purpose: To prospectively evaluate the feasibility of dual-energy (DE) split-bolus CT-urography (CTU) and the quality of virtual non-enhanced images (VNEI) and DE combined nephrographic-excretory phase images (CNEPI), and to estimate radiation dose reduction if true non-enhanced images (TNEI) could be omitted. Patients and methods: Between August and September 2011, 30 consecutive patients with confirmed or suspected urothelial cancer or with hematuria underwent DE CT. Single-energy TNEI and DE CNEPI were obtained. VNEI was reconstructed from CNEPI. Image quality of CNEPI and VNEI was evaluated using a 5-point scale. The attenuation of urine in the bladder on TNEI and VNEI was measured. The CT dose index volume (CTDI (vol)) of the two scans was recorded. Results: The mean image quality score of CNEPI and VNEI was 4.7 and 3.3, respectively. The mean differences in urine attenuation between VNEI and TNEI were 14 {+-} 15 [SD] and -16 {+-} 29 in the anterior and posterior parts of the bladder, respectively. The mean CTDI (vol) for TNEI and CNEPI was 11.8 and 10.9 mGy, respectively. Omission of TNEI could reduce the total radiation dose by 52%. Conclusion: DE split-bolus CTU is technically feasible and can reduce radiation exposure; however, an additional TNEI scan is necessary when the VNEI quality is poor or quantitative evaluation of urine attenuation is required.

  2. Systemic staging for urate crystal deposits with dual-energy CT and ultrasound in patients with suspected gout.

    Science.gov (United States)

    Huppertz, Alexander; Hermann, Kay-Geert A; Diekhoff, Torsten; Wagner, Moritz; Hamm, Bernd; Schmidt, Wolfgang A

    2014-06-01

    Objective of the study is to compare the diagnostic accuracy for detecting monosodium urate crystal deposits between dual-energy CT (DECT) and ultrasound (US). Sixty consecutive patients (49 men, mean age 62 years) with clinically suspected gout were included in this case-control study. DECT and US of feet, knees, hands and elbows were performed in all patients. Polarisation microscopy of synovial fluid or a score incorporating serum uric acid level, first MTP joint involvement, gender, previous patient-reported arthritis attack, cardiovascular diseases, joint redness and onset within 1 day was used as standard of reference. Standard of reference classified 39 patients as gout positive. Sixteen patients had gout and a concomitant rheumatic disease. Sensitivities for diagnosis of gout disease were 84.6 % (33/39) for DECT and 100 % (39/39) for US. Specificities were 85.7 % (18/21) for DECT and 76.2 % (16/21) for US. Positive and negative predictive values were 91.7 % (33/36) and 75.0 % (18/24) for DECT, 88.6 % (39/44) and 100 % (16/16) for US, respectively. Urate crystals were detected most frequently in MTP1 joints (DECT 20/78, US 58/78), any other toe joints (DECT 25/78, US 62/78) and knees (DECT 41/78, US 31/78). The volumetry of DECT computed a mean urate crystal deposit load of 2.1 cm(3) (SD 9.6 cm(3)). A mean effective dose of ≤0.5 mSv was estimated. DECT is more specific for the diagnosis of gout than US. However, it fails to detect small urate crystal deposits. It might be particularly useful for patients with ambivalent findings, concomitant rheumatic diseases and with non-conclusive joint aspiration.

  3. A reliable method for measuring proximal tibia and distal femur bone mineral density using dual-energy X-ray absorptiometry

    NARCIS (Netherlands)

    Bakkum, Arjan J. T.; Janssen, Thomas W. J.; Rolf, Marijn P.; Roos, Jan C.; Burcksen, Jos; Knol, Dirk L.; de Groot, Sonja

    2014-01-01

    Purpose: To assess the intra- and inter-rater reliability of a standardized protocol for measuring proximal tibia and distal femur bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA). Methods: Ten able-bodied individuals (7 males) participated in this study. During one measuremen

  4. Diagnostic usefulness of dual-energy computed tomography in evaluation of the severity of acute pulmonary thromboembolism

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sung Min; Beak, Jang Mi; Yoon, Yeon Hong; Kim, Yun Hyeon [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Seon, Hyun Ju [Dept. of Radiology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Lee, Seung Jin [Dept. of Radiology, Chonnam National University Bitgoeul Hospital, Gwangju (Korea, Republic of)

    2015-01-15

    To evaluate the usefulness of dual-energy computed tomography (DECT) in severity assessment of patients with acute pulmonary thromboembolism (APTE). We evaluated 61 patients diagnosed as APTE from 2011 to 2012 in a retrospective analysis of the severity assessment indices according to Criteria by European Society of Cardiology as well as pulmonary CT angiographic obstruction score (OS) and lung perfusion index (pulmonary perfusion defect score; DS) by DECT. The correlation between OS, DS and the severity of pulmonary thromboembolism was evaluated using logit analysis. Patients with high OS also showed significantly higher DS values (p < 0.001). There was a significant correlation between both the OS and DS values and the severity of the pulmonary thromboembolism using simple sequence logit analysis (p < 0.001). However, only the DS value showed a very high correlation with the severity of pulmonary thromboembolism using multiple sequence logit analysis. DECT provides a more useful marker for the diagnosis and severity assessment of pulmonary thromboembolism by checking the degree of lung perfusion as well as determining the existence of APTE in patients with suspected pulmonary thromboembolism.

  5. Designing Dual-Active Bridge (DAB) converter for energy storage/recovery systems in a lighting smart grid context

    OpenAIRE

    Rico Secades, Manuel; García Llera, Daniel; López Corominas, Emilio Ramón; Calleja Rodríguez, Antonio Javier

    2014-01-01

    Lighting Systems are suffering and important evolution with the introduction of LED lighting systems with new strategies of energy savings, incorporation of renewable energy sources and optionally a bidirectional interconnection with the mains (AC grid or DC interconnection bus). Lighting Systems are moving to Lighting Smart Grids and step by step integrating in Smart City strategies. In this context design of modular and efficient energy storage/recovery systems are gaining importance lookin...

  6. 14 CFR 105.43 - Use of single-harness, dual-parachute systems.

    Science.gov (United States)

    2010-01-01

    ... making the next jump with that parachute, or a non-certificated person under the direct supervision of a... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Use of single-harness, dual-parachute... TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES PARACHUTE OPERATIONS Parachute Equipment...

  7. PVAL breast phantom for dual energy calcification detection

    Science.gov (United States)

    Koukou, V.; Martini, N.; Velissarakos, K.; Gkremos, D.; Fountzoula, C.; Bakas, A.; Michail, C.; Kandarakis, I.; Fountos, G.

    2015-09-01

    Microcalcifications are the main indicator for breast cancer. Dual energy imaging can enhance the detectability of calcifications by suppressing the tissue background. Two digital images are obtained using two different spectra, for the low- and high-energy respectively, and a weighted subtracted image is produced. In this study, a dual energy method for the detection of the minimum breast microcalcification thickness was developed. The used integrated prototype system consisted of a modified tungsten anode X-ray tube combined with a high resolution CMOS sensor. The breast equivalent phantom used was an elastically compressible gel of polyvinyl alcohol (PVAL). Hydroxyapatite was used to simulate microcalcifications with thicknesses ranging from 50 to 500 μm. The custom made phantom was irradiated with 40kVp and 70kVp. Tungsten (W) anode spectra filtered with 100μm Cadmium and 1000pm Copper, for the low- and high-energy, respectively. Microcalcifications with thicknesses 300μm or higher can be detected with mean glandular dose (MGD) of 1.62mGy.

  8. Phase calibration of sonar systems using standard targets and dual-frequency transmission pulses.

    Science.gov (United States)

    Islas-Cital, Alan; Atkins, Philip R; Foo, Kae Y; Picó, Ruben

    2011-10-01

    The phase angle component of the complex frequency response of a sonar system operating near transducer resonance is usually distorted. Interpretation and classification of the received sonar signal benefits from the preservation of waveform fidelity over the full bandwidth. A calibration process that measures the phase response in addition to the amplitude response is thus required. This paper describes an extension to the standard-target calibration method to include phase angle, without affecting the experimental apparatus, by using dual-frequency transmission pulses and frequency-domain data processing. This approach reduces the impact of unknown range and sound speed parameters upon phase calibration accuracy, as target phase is determined from the relationship of the two frequency components instead of relying on a local phase reference. Tungsten carbide spheres of various sizes were used to simultaneously calibrate the amplitude and phase response of an active sonar system in a laboratory tank. Experimental measurements of target phase spectra are in good agreement with values predicted from a theoretical model based upon full-wave analysis, over an operating frequency of 50-125 kHz.

  9. Soft tissue discrimination ex vivo by dual energy computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zachrisson, H., E-mail: helene.zachrisson@lio.s [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Engstroem, E. [Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Engvall, J.; Wigstroem, L. [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Clinical Physiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Smedby, O.; Persson, A. [Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden); Radiology, Department of Medical and Health Sciences (IMH), Linkoeping University, Linkoeping University Hospital, SE-581 85 Linkoeping (Sweden)

    2010-08-15

    Purpose: Dual Energy Computed Tomography (DECT) may provide additional information about the chemical composition of tissues compared to examination with a single X-ray energy. The aim of this in vitro study was to test whether combining two energies may significantly improve the detection of soft tissue components commonly present in arterial plaques. Methods: Tissue samples of myocardial and psoas muscle, venous and arterial thrombus as well as fat from different locations were scanned using a SOMATOM Definition Dual Source CT system (Siemens AG, Medical Solutions, Forchheim, Germany) with simultaneous tube voltages of 140 and 80 kV. The attenuation (Hounsfield units, HU) at 80 and 140 kV was measured in representative regions of interest, and the association between measured HU values and tissue types was tested with logistic regression. Results: The combination of two energy levels (80 and 140 kV) significantly improved (p < 0.001) the ability to correctly classify venous thrombus vs arterial thrombus, myocardium or psoas; arterial thrombus vs myocardium or psoas; myocardium vs psoas; as well as the differentiation between fat tissue from various locations. Single energy alone was sufficient for distinguishing fat from other tissues. Conclusion: DECT offers significantly improved in vitro differentiation between soft tissues occurring in plaques. If this corresponds to better tissue discrimination in vivo needs to be clarified in future studies.

  10. Multiparametric Evaluation of Head and Neck Squamous Cell Carcinoma Using a Single-Source Dual-Energy CT with Fast kVp Switching: State of the Art

    Directory of Open Access Journals (Sweden)

    Stephanie Lam

    2015-11-01

    Full Text Available There is an increasing body of evidence establishing the advantages of dual-energy CT (DECT for evaluation of head and neck squamous cell carcinoma (HNSCC. Focusing on a single-source DECT system with fast kVp switching, we will review the principles behind DECT and associated post-processing steps that make this technology especially suitable for HNSCC evaluation and staging. The article will review current applications of DECT for evaluation of HNSCC including use of different reconstructions to improve tumor conspicuity, tumor-normal soft tissue interface, accuracy of invasion of critical structures such as thyroid cartilage, and reduce dental artifact. We will provide a practical approach for DECT implementation into routine clinical use and a multi-parametric approach for scan interpretation based on the experience at our institution. The article will conclude with a brief overview of potential future applications of the technique.

  11. Evaluation of hyperdense renal lesions incidentally detected on single-phase post-contrast CT using dual-energy CT

    Science.gov (United States)

    Park, Jung Jae; Park, Byung Kwan

    2016-01-01

    Objective: To investigate the utility of dual-energy CT (DECT) for differentiating between solid and benign cystic lesions presenting as hyperdense renal lesions incidentally detected on single-phase post-contrast CT. Methods: 90 hyperdense renal lesions incidentally detected on single-phase post-contrast CT were evaluated with follow-up DECT. DECT protocols included true non-contrast (TNC), DE corticomedullary and DE late nephrographic phase imaging. The CT numbers of hyperdense renal lesions were calculated on linearly blended and iodine overlay (IO) images, and the results were compared. Results: In total, 47 benign cystic and 43 solid renal lesions were analyzed. For differentiating between solid and benign cystic lesions on the two phases, the specificity and accuracy of all lesions and lesions  0.05). For all types of lesions ≥1.5 cm, the CT numbers between linearly blended and IO images and between TNC and virtual non-contrast images were not statistically different (p > 0.05). Conclusion: DECT may be useful for differentiating between solid and benign cystic lesions presenting as hyperdense renal lesions incidentally detected on single-phase post-contrast CT, particularly with the size ≥1.5 cm. Advances in knowledge: DECT may be used to characterize hyperdense renal lesions ≥1.5 cm incidentally detected on single-phase post-contrast CT, without the use of TNC images. PMID:27043480

  12. Volume-based quantification using dual-energy computed tomography in the differentiation of thymic epithelial tumours: an initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Suyon; Hur, Jin; Im, Dong Jin; Suh, Young Joo; Hong, Yoo Jin; Lee, Hye-Jeong; Kim, Young Jin; Choi, Byoung Wook [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Seoul (Korea, Republic of); Han, Kyunghwa [Yonsei University College of Medicine, Yonsei Biomedical Research Institute, Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Seoul (Korea, Republic of); Kim, Dae Joon; Lee, Chang Young [Yonsei University College of Medicine, Department of Thoracic and Cardiovascular Surgery, Seoul (Korea, Republic of); Shin, Ha Young [Yonsei University College of Medicine, Department of Neurology, Seoul (Korea, Republic of)

    2017-05-15

    To investigate the diagnostic value of dual-energy computed tomography (DECT) in differentiating between low- and high-risk thymomas and thymic carcinomas. Our institutional review board approved this study, and patients provided informed consent. We prospectively enrolled 37 patients (20 males, mean age: 55.6 years) with thymic epithelial tumour. All patients underwent DECT. For quantitative analysis, two reviewers measured the following tumour parameters: CT attenuation value in contrast Hounsfield units (CHU), iodine-related HU and iodine concentration (mg/ml). Pathological results confirmed the final diagnosis. Of the 37 thymic tumours, 23 (62.2 %) were low-risk thymomas, five (13.5 %) were high-risk thymomas and nine (24.3 %) were thymic carcinomas. According to quantitative analysis, iodine-related HU and iodine concentration were significantly different among low-risk thymomas, high-risk thymomas and thymic carcinomas (median: 29.78 HU vs. 14.55 HU vs. 19.95 HU, p = 0.001 and 1.92 mg/ml vs. 0.99 mg/ml vs. 1.18 mg/ml, p < 0.001, respectively). DECT using a quantitative analytical method based on iodine concentration measurement can be used to differentiate among thymic epithelial tumours using single-phase scanning. (orig.)

  13. Measurement precision of body composition variables in elite wheelchair athletes, using dual-energy X-ray absorptiometry.

    Science.gov (United States)

    Keil, Mhairi; Totosy de Zepetnek, Julia O; Brooke-Wavell, Katherine; Goosey-Tolfrey, Victoria L

    2016-01-01

    The purpose of this study was to assess the reproducibility of body composition measurements by dual-energy X-ray absorptiometry (DXA) in 12 elite male wheelchair basketball players (age 31 ± 7 years, BMI 21 ± 2 kg/m(2) and onset of disability 25 ± 9 years). Two whole body scans were performed on each participant in the supine position on the same day, using Lunar Prodigy Advance DXA (GE Lunar, Madison, WI, USA). Participants dismounted from the scanning table and were repositioned in-between the first and second scan. Whole body coefficient of variation (CV) values for bone mineral content (BMC), fat mass (FM) and soft tissue lean mass (LTM) were all effect of treatment intervention in an individual is 1.0 kg, 1.1 kg, 0.12 kg for FM, LTM, and BMC, respectively. This information can be used to determine meaningful changes in body composition when assessed using the same methods longitudinally. Whilst there may be challenges in the correct positioning of an individual with disability that can introduce greater measurement error, DXA is a highly reproducible technique in the estimation of total and regional body composition of elite wheelchair basketball athletes.

  14. Measuring body composition in dogs using multifrequency bioelectrical impedance analysis and dual energy X-ray absorptiometry.

    Science.gov (United States)

    Rae, L S; Vankan, D M; Rand, J S; Flickinger, E A; Ward, L C

    2016-06-01

    Thirty-five healthy, neutered, mixed breed dogs were used to determine the ability of multifrequency bioelectrical impedance analysis (MFBIA) to predict accurately fat-free mass (FFM) in dogs using dual energy X-ray absorptiometry (DXA)-measured FFM as reference. A second aim was to compare MFBIA predictions with morphometric predictions. MFBIA-based predictors provided an accurate measure of FFM, within 1.5% when compared to DXA-derived FFM, in normal weight dogs. FFM estimates were most highly correlated with DXA-measured FFM when the prediction equation included resistance quotient, bodyweight, and body condition score. At the population level, the inclusion of impedance as a predictor variable did not add substantially to the predictive power achieved with morphometric variables alone; in individual dogs, impedance predictors were more valuable than morphometric predictors. These results indicate that, following further validation, MFBIA could provide a useful tool in clinical practice to objectively measure FFM in canine patients and help improve compliance with prevention and treatment programs for obesity in dogs.

  15. Cerebral artery evaluation of dual energy CT angiography with dual source CT

    Institute of Scientific and Technical Information of China (English)

    MA Rui; LIU Cheng; DENG Kai; SONG Shao-juan; WANG Dao-ping; HUANG Ling

    2010-01-01

    Background Conventional computed tomography angiography (CTA) is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection (MIP) image was generated quickly by dual energy bone remove (DEBR group); merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove (CoBR group). Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student's t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen's kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR (P0.5). Interobserver agreement for all vessel segments was excellent (kappa=0.97). Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

  16. Using Edge-Preserving Algorithm with Non-local Mean for Significantly Improved Image-Domain Material Decomposition in Dual Energy CT

    CERN Document Server

    Zhao, Wei; Xing, Lei; Xie, Yaoqin; Xiong, Guanglei; Elmore, Kimberly; Zhu, Jun; Wang, Luyao; Min, James K

    2016-01-01

    Increased noise is a general concern for dual-energy material decomposition. Here, we develop an image-domain material decomposition algorithm for dual-energy CT (DECT) by incorporating an edge-preserving filter into the Local HighlY constrained backPRojection Reconstruction (HYPR-LR) framework. With effective use of the non-local mean, the proposed algorithm, which is referred to as HYPR-NLM, reduces the noise in dual energy decomposition while preserving the accuracy of quantitative measurement and spatial resolution of the material-specific dual energy images. We demonstrate the noise reduction and resolution preservation of the algorithm with iodine concentrate numerical phantom by comparing the HYPR-NLM algorithm to the direct matrix inversion, HYPR-LR and iterative image-domain material decomposition (Iter-DECT). We also show the superior performance of the HYPR-NLM over the existing methods by using two sets of cardiac perfusing imaging data. The reference drawn from the comparison study includes: (1) ...

  17. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-03-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives ({{η}}_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  18. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-08-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives (η_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  19. "How to" incorporate dual-energy imaging into a high volume abdominal imaging practice.

    Science.gov (United States)

    Tamm, Eric P; Le, Ott; Liu, Xinming; Layman, Rick R; Cody, Dianna D; Bhosale, Priya R

    2017-03-01

    Dual-energy CT imaging has many potential uses in abdominal imaging. It also has unique requirements for protocol creation depending on the dual-energy scanning technique that is being utilized. It also generates several new types of images which can increase the complexity of image creation and image interpretation. The purpose of this article is to review, for rapid switching and dual-source dual-energy platforms, methods for creating dual-energy protocols, different approaches for efficiently creating dual-energy images, and an approach to navigating and using dual-energy images at the reading station all using the example of a pancreatic multiphasic protocol. It will also review the three most commonly used types of dual-energy images: "workhorse" 120kVp surrogate images (including blended polychromatic and 70 keV monochromatic), high contrast images (e.g., low energy monochromatic and iodine material decomposition images), and virtual unenhanced images. Recent developments, such as the ability to create automatically on the scanner the most common dual-energy images types, namely new "Mono+" images for the DSDECT (dual-source dual-energy CT) platform will also be addressed. Finally, an approach to image interpretation using automated "hanging protocols" will also be covered. Successful dual-energy implementation in a high volume practice requires careful attention to each of these steps of scanning, image creation, and image interpretation.

  20. Optimization of use of waste in the future energy system

    DEFF Research Database (Denmark)

    Münster, Marie; Meibom, Peter

    2011-01-01

    Alternative uses of waste for energy production become increasingly interesting when considered from two perspectives, that of waste management and the energy system perspective. This paper presents the results of an enquiry into the use of waste in a future energy system. The analysis...... was performed using the energy system analysis model, Balmorel. The study is focused on Germany and the Nordic countries and demonstrates the optimization of both investments and production within the energy systems. The results present cost optimization excluding taxation concerning the use of waste for energy...... production in Denmark in a 2025 scenario with 48% renewable energy. Investments in a range of waste conversion technologies are facilitated, including waste incineration, co-combustion with coal, anaerobic digestion, and gasification. The most economically feasible solutions are found to be incineration...

  1. Mach-Zehnder modulator modulated radio-over-fiber transmission system using dual wavelength linearization

    Science.gov (United States)

    Zhu, Ran; Hui, Ming; Shen, Dongya; Zhang, Xiupu

    2017-02-01

    In this paper, dual wavelength linearization (DWL) technique is studied to suppress odd and even order nonlinearities simultaneously in a Mach-Zehnder modulator (MZM) modulated radio-over-fiber (RoF) transmission system. A theoretical model is given to analyze the DWL employed for MZM. In a single-tone test, the suppressions of the second order harmonic distortion (HD2) and third order harmonic distortion (HD3) at the same time are experimentally verified at different bias voltages of the MZM. The measured spurious-free dynamic ranges (SFDRs) with respect to the HD2 and HD3 are improved simultaneously compared to using a single laser. The output P1 dB is also improved by the DWL technique. Moreover, a WiFi signal is transmitted in the RoF system to test the linearization for broadband signal. The result shows that more than 1 dB improvement of the error vector magnitude (EVM) is obtained by the DWL technique.

  2. Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

    Science.gov (United States)

    Majewski, Stanislaw; Umeno, Marc M.

    2011-09-13

    A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

  3. An RF Therapy System for Breast Cancer Using Dual Deformable Mirrors — Computational Study

    Science.gov (United States)

    Arunachalam, Kavitha; Udpa, Satish S.; Udpa, Lalita

    2007-03-01

    Breast cancer is the second leading cause of cancer deaths amongst women in the United States. In the past two decades, the potential of non-ionizing high power RF waves to destroy cancerous biological tissues is actively investigated for cancer therapy. This paper presents the computational feasibility study of an alternative mode of electromagnetic radiation therapy that employs dual source and deformable mirror. The adaptive focusing capability of the deformable mirror is exploited for preferential energy deposition at the tumor site in the breast irradiated by electromagnetic radiation. The outcome of the computational study for the proposed deformable mirror-based thermal therapy for breast cancer is presented in this paper.

  4. Numerical Comparison of NASA's Dual Brayton Power Generation System Performance Using CO2 or N2 as the Working Fluid

    Science.gov (United States)

    Ownens, Albert K.; Lavelle, Thomas M.; Hervol, David S.

    2010-01-01

    A Dual Brayton Power Conversion System (DBPCS) has been tested at the NASA Glenn Research Center using Nitrogen (N2) as the working fluid. This system uses two closed Brayton cycle systems that share a common heat source and working fluid but are otherwise independent. This system has been modeled using the Numerical Propulsion System Simulation (NPSS) environment. This paper presents the results of a numerical study that investigated system performance changes resulting when the working fluid is changed from gaseous (N2) to gaseous carbon dioxide (CO2).

  5. Comprehensive analysis of proton range uncertainties related to stopping-power-ratio estimation using dual-energy CT imaging

    Science.gov (United States)

    Li, B.; Lee, H. C.; Duan, X.; Shen, C.; Zhou, L.; Jia, X.; Yang, M.

    2017-09-01

    The dual-energy CT-based (DECT) approach holds promise in reducing the overall uncertainty in proton stopping-power-ratio (SPR) estimation as compared to the conventional stoichiometric calibration approach. The objective of this study was to analyze the factors contributing to uncertainty in SPR estimation using the DECT-based approach and to derive a comprehensive estimate of the range uncertainty associated with SPR estimation in treatment planning. Two state-of-the-art DECT-based methods were selected and implemented on a Siemens SOMATOM Force DECT scanner. The uncertainties were first divided into five independent categories. The uncertainty associated with each category was estimated for lung, soft and bone tissues separately. A single composite uncertainty estimate was eventually determined for three tumor sites (lung, prostate and head-and-neck) by weighting the relative proportion of each tissue group for that specific site. The uncertainties associated with the two selected DECT methods were found to be similar, therefore the following results applied to both methods. The overall uncertainty (1σ) in SPR estimation with the DECT-based approach was estimated to be 3.8%, 1.2% and 2.0% for lung, soft and bone tissues, respectively. The dominant factor contributing to uncertainty in the DECT approach was the imaging uncertainties, followed by the DECT modeling uncertainties. Our study showed that the DECT approach can reduce the overall range uncertainty to approximately 2.2% (2σ) in clinical scenarios, in contrast to the previously reported 1%.

  6. Is bone mineral density measurement using dual-energy X-ray absorptiometry affected by gamma rays?

    Science.gov (United States)

    Xie, Liang-Jun; Li, Jian-Fang; Zeng, Feng-Wei; Jiang, Hang; Cheng, Mu-Hua; Chen, Yi

    2013-01-01

    The objective of this study was to determine whether the gamma rays emitted from the radionuclide effect bone mineral density (BMD) measurement. Nine subjects (mean age: 56 ± 17.96 yr) scheduled for bone scanning underwent BMD measurement using dual-energy X-ray absorptiometry (DXA) (Hologic/Discovery A) before and 1, 2, and 4 h after injection of technetium-99m-methylene diphosphonate (99mTc-MDP). Ten subjects (mean age: 41 ± 15.47 yr) scheduled for therapy of differentiated thyroid carcinoma with iodine-131 underwent BMD measurement before and 2 h after therapeutic radionuclide administration. All patients were given whole body BMD measurement, including head, arm, ribs, lumbar spine, pelvis, and leg sites. Besides, patients who referred to radioiodine therapy were given total hip and femoral neck BMD measurement as well. No statistically significant changes in BMD values were detected after 99mTc-MDP and iodine-131 administration for all measurement sites (p > 0.05), and individual difference of BMD before and after radionuclide imaging or therapy was less than the least significant change in lumbar spine, total hip, and femoral neck. In conclusion, BMD measurements are not influenced by the gamma rays emitted from technetium-99m and iodine-131. DXA bone densitometry may be performed simultaneously with bone scanning and radioiodine therapy.

  7. Dynamic molecular imaging of cardiac innervation using a dual headpinhole SPECT system

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jicun; Boutchko, Rostyslav; Sitek, Arkadiusz; Reutter, BryanW.; Huesman, Ronald H.; Gullberg, Grant T.

    2008-03-29

    Typically 123I-MIBG is used for the study of innervation andfunction of the sympathetic nervous system in heart failure. The protocolinvolves two studies: first a planar or SPECT scan is performed tomeasure initial uptake of the tracer, followed some 3-4 hours later byanother study measuring the wash-out of the tracer from the heart. A fastwash-out is indicative of a compromised heart. In this work, a dual headpinhole SPECT system was used for imaging the distribution and kineticsof 123I-MIBG in the myocardium of spontaneous hypertensive rats (SHR) andnormotensive Wistar Kyoto (WKY) rats. The system geometry was calibratedbased on a nonlinear point projection fitting method using a three-pointsource phantom. The angle variation effect of the parameters was modeledwith a sinusoidal function. A dynamic acquisition was performed byinjecting 123I-MIBG into rats immediately after starting the dataacquisition. The detectors rotated continuously performing a 360o dataacquisition every 90 seconds. We applied the factor analysis (FA)methodand region of interest (ROI) sampling method to obtain time activitycurves (TACs)in the blood pool and myocardium and then appliedtwo-compartment modeling to estimate the kinetic parameters. Since theinitial injection bolus is too fast for obtaining a consistenttomographic data set in the first few minutes of the study, we appliedthe FA method directly to projections during the first rotation. Then thetime active curves for blood and myocardial tissue were obtained from ROIsampling. The method was applied to determine if there were differencesin the kinetics between SHR and WKY rats and requires less time byreplacing the delayed scan at 3-4 hours after injection with a dynamicacquisition over 90 to 120 minutes. The results of a faster washout and asmaller distribution volume of 123IMIBG near the end of life in the SHRmodel of hypertrophic cardiomyopthy may be indicative of a failing heartin late stages of heart failure.

  8. Illegal intra-corporeal packets: can dual energy CT be used for the evaluation of cocaine concentration? A cross sectional study.

    Science.gov (United States)

    Platon, Alexandra; Becker, Minerva; Becker, Christoph D; Lock, Eric; Wolff, Hans; Perneger, Thomas; Poletti, Pierre-Alexandre

    2016-01-13

    The recent implementation of the dual energy technology on CT-scanners has opened new perspectives in tissue and material characterization. This study aims to evaluate whether dual energy CT can be used to assess the concentration of cocaine of intra-intestinal illegal packets. The study was approved by the institutional review board of our institution (CER 13_027_R). From November 2010 to May 2013, all consecutive conveyors in whom a low-dose abdominal CT (LDCT) revealed the presence of illegal intra-corporeal drug packets underwent a dual energy CT series (gemstone spectral imaging) targeted on one container. The mean radiological density (HU) of these packets was measured on the LDCT series, and on the monochromatic dual energy series, at 40 and 140 keV. The difference between the HU at 40 and 140 keV was reported as ∆HU. The effective atomic number Z(eff) was also measured on the monochromatic series. A chemical analysis was performed after expulsion to select cocaine containing packets, and to determine their cocaine concentrations. A correlation analysis was performed between HU, ∆HU and Z(eff), with regard to the percentage of cocaine. Fifty-four cocaine conveyors were included. The mean cocaine content of the packets was 36.8% (range 11.2-80, SD 15.4), the mean radiologic density 105 HU, the mean Z(eff) 8.7 and the mean ∆HU 163. The cocaine content was correlated with the ∆HU (0.57, p 200 was 0.9 (9 of 10) sensitive and 0.82 (36 of 44) specific to predict a cocaine concentration higher than 50%. Measuring ∆HU or Z(eff) on dual energy monochromatic CT series can be used to detect ingested packets with cocaine concentration >50%.

  9. Accuracy of iodine removal using dual-energy CT with or without a tin filter: an experimental phantom study.

    Science.gov (United States)

    Kawai, Tatsuya; Takeuchi, Mitsuru; Hara, Masaki; Ohashi, Kazuya; Suzuki, Hirochika; Yamada, Kiyotaka; Sugimura, Yuya; Shibamoto, Yuta

    2013-10-01

    The effects of a tin filter on virtual non-enhanced (VNE) images created by dual-energy CT have not been well evaluated. To compare the accuracy of VNE images between those with and without a tin filter. Two different types of columnar phantoms made of agarose gel were evaluated. Phantom A contained various concentrations of iodine (4.5-1590 HU at 120 kVp). Phantom B consisted of a central component (0, 10, 25, and 40 mgI/cm(3)) and a surrounding component (0, 50, 100, and 200 mgI/cm(3)) with variable iodine concentration. They were scanned by dual-source CT in conventional single-energy mode and dual-energy mode with and without a tin filter. CT values on each gel at the corresponding points were measured and the accuracy of iodine removal was evaluated. On VNE images, the CT number of the gel of Phantom A fell within the range between -15 and +15 HU under 626 and 881 HU at single-energy 120 kVp with and without a tin filter, respectively. With attenuation over these thresholds, iodine concentration of gels was underestimated with the tin filter but overestimated without it. For Phantom B, the mean CT numbers on VNE images in the central gel component surrounded by the gel with iodine concentrations of 0, 50, 100, and 200 mgI/cm(3) were in the range of -19-+6 HU and 21-100 HU with and without the tin filter, respectively. Both with and without a tin filter, iodine removal was accurate under a threshold of iodine concentration. Although a surrounding structure with higher attenuation decreased the accuracy, a tin filter improved the margin of error.

  10. Dual energy CT in patients with polycystic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, Nikolaus; Reiser, Maximilian F.; Graser, Anno [University of Munich, Department of Clinical Radiology, Munich (Germany); Staehler, Michael [University of Munich, Department of Urology, Munich (Germany); Siegert, Sabine [University of Munich, Department of Pathology, Munich (Germany)

    2012-10-15

    To evaluate the diagnostic efficacy of dual source-dual energy CT (DECT) in the detection of neoplasia in patients with polycystic kidney disease (PKD). A total of 21 patients with PKD underwent DECT on a dual source system, using kVp settings of Sn140/100 or 140/80. Colour-coded iodine maps and virtual unenhanced images were used to determine enhancement within cysts and to differentiate haemorrhagic from simple cysts. A cut-off of 15 HU was used as a threshold for malignancy. In patients with malignancy, histopathology was the gold standard; otherwise, patients underwent follow-up imaging for 150-908 days. On the basis of measured enhancement, 13 enhancing masses were seen in 4 patients (12 renal cell cancers and 1 adenoma); follow-up imaging showed no malignancy in 18 patients. Cysts did not enhance by more than 15 HU, whereas masses showed a mean enhancement of 45 (25-123) HU. Average radiation exposure was 9.6 mSv for the biphasic protocol and 5.8 mSv for DECT only. DECT greatly facilitates the detection of malignancy in patients with polycystic kidney disease, at the same time reducing radiation exposure by omission of a true unenhanced phase. (orig.)

  11. Design of an Image-Servo Mask Alignment System Using Dual CCDs with an XXY Stage

    Directory of Open Access Journals (Sweden)

    Chih-Jer Lin

    2016-02-01

    Full Text Available Mask alignment of photolithography technology is used in many applications, such as micro electro mechanical systems’ semiconductor process, printed circuits board, and flat panel display. As the dimensions of the product are getting smaller and smaller, the automatic mask alignment of photolithography is becoming more and more important. The traditional stacked XY-Θz stage is heavy and it has cumulative flatness errors due to its stacked assembly mechanism. The XXY stage has smaller cumulative error due to its coplanar design and it can move faster than the traditional XY-Θz stage. However, the relationship between the XXY stage’s movement and the commands of the three motors is difficult to compute, because the movements of the three motors on the same plane are coupling. Therefore, an artificial neural network is studied to establish a nonlinear mapping from the desired position and orientation of the stage to three motors’ commands. Further, this paper proposes an image-servo automatic mask alignment system, which consists of a coplanar XXY stage, dual GIGA-E CCDs with lens and a programmable automatic controller (PAC. Before preforming the compensation, a self-developed visual-servo provides the positioning information which is obtained from the image processing and pattern recognition according to the specified fiducial marks. To obtain better precision, two methods including the center of gravity method and the generalize Hough Transformation are studied to correct the shift positioning error.

  12. DOWNSLOPE EROSION PROCESS UNDER UPSLOPE RUNOFF AND SEDIMENT USING A DUAL-BOX SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Peiqing XIAO; Fenli ZHENG; Wenyi YAO

    2005-01-01

    Soil erosion at the hilly-gully region of the Loess Plateau has obvious vertical erosion zonation from watershed boundary to gully edge. Meanwhile, upslope runoff and sediment have a significant impact on the downslope erosion process. But due to the limits of research methods, there is not much data available to quantify the effects of upslope runoff and sediment on the downslope erosion process under different conditions. The objective of this study was to quantify the effects of upslope runoff and sediment on the downslope erosion process using a dual-box system with a 15° gradient consisting of a 2 m-long feeder box and a 5 m-long test box under different runoff rates and sediment concentrations in upslope runoff, rainfall intensities and soil surface conditions. The results showed that the sediment regime was detachment-transport dominant at steep hillslopes. The net sediment delivery S caused by upslope runoff was controlled by sediment concentration in upslope runoff, especially by interaction of the rainfall intensity, runoff rate, surface condition and dominant erosion process. The net sediment delivery S accounted for the total sediment delivery Sft at downslope 31.7% to 97.3% and 27.8 to 89.7% for both loose and compact surface treatments, respectively. Rainfall intensity, slope gradient, surface condition, and rill erosion development had important influences on the downslope erosion process.

  13. Energy Management of Dual-Source Propelled Electric Vehicle using Fuzzy Controller Optimized via Genetic Algorithm

    DEFF Research Database (Denmark)

    Khoobi, Saeed; Halvaei, Abolfazl; Hajizadeh, Amin

    2016-01-01

    of EV relies too much on the expert experience and it may lead to sub-optimal performance. This paper develops an optimized fuzzy controller using genetic algorithm (GA) for an electric vehicle equipped with two power bank including battery and super-capacitor. The model of EV and optimized fuzzy...

  14. Design of an aircraft landing system using dual-frequency GNSS

    Science.gov (United States)

    Konno, Hiroyuki

    There is a strong demand for new all-weather navigation aids to support aircraft precision approach and landing. The Federal Aviation Administration's Local Area Augmentation System (LAAS) is one such navigation aid that uses the Global Positioning System (GPS) to estimate aircraft location. LAAS is required to provide very high levels of accuracy, integrity, continuity, and availability, and the integrity requirement of one undetected navigation failure in a billion approaches has been a critical challenge in the design of this system. Tremendous efforts have developed methods to guarantee integrity for various potential anomalies that might threaten LAAS-aided landing. Currently, almost all these risks are mitigated by existing methods. One issue that remains is the risk due to ionosphere anomalies. This dissertation introduces novel integrity algorithms for ionosphere anomalies that take advantage of GPS modernization---undergoing changes in the GPS system that enhance civil user capabilities. This modernization includes adding new GPS civil signals, and these signals make possible multiple-frequency techniques. This research focuses on two types of dual-frequency carrier-smoothing methods---Divergence-Free Smoothing and Ionosphere-Free Smoothing---and develops integrity algorithms for ionosphere anomalies using these methods. Simulations show that the first algorithm, using Ionosphere-Free Smoothing, can achieve 96% to 99.9% availability at best over a broad region of the Conterminous United States (CONUS). This level of availability is unacceptably low for practical use. However, a benefit is that the resulting availability is not a function of the ionosphere condition. The second algorithm, based on Divergence-Free Smoothing, is shown by simulations to achieve more than 99.9% availability over more than 70% of CONUS under nominal ionosphere conditions. However, it has the potential to completely lose availability under severe ionosphere conditions. Taking

  15. Segmental Musculoskeletal Examinations using Dual-Energy X-Ray Absorptiometry (DXA: Positioning and Analysis Considerations

    Directory of Open Access Journals (Sweden)

    Nicolas H. Hart, Sophia Nimphius, Tania Spiteri, Jodie L. Cochrane, Robert U. Newton

    2015-09-01

    Full Text Available Musculoskeletal examinations provide informative and valuable quantitative insight into muscle and bone health. DXA is one mainstream tool used to accurately and reliably determine body composition components and bone mass characteristics in-vivo. Presently, whole body scan models separate the body into axial and appendicular regions, however there is a need for localised appendicular segmentation models to further examine regions of interest within the upper and lower extremities. Similarly, inconsistencies pertaining to patient positioning exist in the literature which influence measurement precision and analysis outcomes highlighting a need for standardised procedure. This paper provides standardised and reproducible: 1 positioning and analysis procedures using DXA and 2 reliable segmental examinations through descriptive appendicular boundaries. Whole-body scans were performed on forty-six (n = 46 football athletes (age: 22.9 ± 4.3 yrs; height: 1.85 ± 0.07 cm; weight: 87.4 ± 10.3 kg; body fat: 11.4 ± 4.5 % using DXA. All segments across all scans were analysed three times by the main investigator on three separate days, and by three independent investigators a week following the original analysis. To examine intra-rater and inter-rater, between day and researcher reliability, coefficients of variation (CV and intraclass correlation coefficients (ICC were determined. Positioning and segmental analysis procedures presented in this study produced very high, nearly perfect intra-tester (CV ≤ 2.0%; ICC ≥ 0.988 and inter-tester (CV ≤ 2.4%; ICC ≥ 0.980 reliability, demonstrating excellent reproducibility within and between practitioners. Standardised examinations of axial and appendicular segments are necessary. Future studies aiming to quantify and report segmental analyses of the upper- and lower-body musculoskeletal properties using whole-body DXA scans are encouraged to use the patient positioning and image analysis procedures

  16. Dual-energy subtraction radiography of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-06-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses.

  17. Predictive Validity of the Body Adiposity Index in Overweight and Obese Adults Using Dual-Energy X-ray Absorptiometry

    Directory of Open Access Journals (Sweden)

    Robinson Ramírez-Vélez

    2016-11-01

    Full Text Available The body adiposity index (BAI is a recent anthropometric measure proven to be valid in predicting body fat percentage (BF% in some populations. However, the results have been inconsistent across populations. This study was designed to verify the validity of BAI in predicting BF% in a sample of overweight/obese adults, using dual-energy X-ray absorptiometry (DEXA as the reference method. A cross-sectional study was conducted in 48 participants (54% women, mean age 41.0 ± 7.3 years old. DEXA was used as the “gold standard” to determine BF%. Pearson’s correlation coefficient was used to evaluate the association between BAI and BF%, as assessed by DEXA. A paired sample t-test was used to test differences in mean BF% obtained with BAI and DEXA methods. To evaluate the concordance between BF% as measured by DEXA and as estimated by BAI, we used Lin’s concordance correlation coefficient and Bland–Altman agreement analysis. The correlation between BF% obtained by DEXA and that estimated by BAI was r = 0.844, p < 0.001. Paired t-test showed a significant mean difference in BF% between methods (BAI = 33.3 ± 6.2 vs. DEXA 39.0 ± 6.1; p < 0.001. The bias of the BAI was −6.0 ± 3.0 BF% (95% CI = −12.0 to 1.0, indicating that the BAI method significantly underestimated the BF% compared to the reference method. Lin’s concordance correlation coefficient was considered stronger (ρc = 0.923, 95% CI = 0.862 to 0.957. In obese adults, BAI presented low agreement with BF% measured by DEXA; therefore, BAI is not recommended for BF% prediction in this overweight/obese sample studied.

  18. Predictive Validity of the Body Adiposity Index in Overweight and Obese Adults Using Dual-Energy X-ray Absorptiometry

    Science.gov (United States)

    Ramírez-Vélez, Robinson; Correa-Bautista, Jorge Enrique; González-Ruíz, Katherine; Vivas, Andrés; García-Hermoso, Antonio; Triana-Reina, Hector Reynaldo

    2016-01-01

    The body adiposity index (BAI) is a recent anthropometric measure proven to be valid in predicting body fat percentage (BF%) in some populations. However, the results have been inconsistent across populations. This study was designed to verify the validity of BAI in predicting BF% in a sample of overweight/obese adults, using dual-energy X-ray absorptiometry (DEXA) as the reference method. A cross-sectional study was conducted in 48 participants (54% women, mean age 41.0 ± 7.3 years old). DEXA was used as the “gold standard” to determine BF%. Pearson’s correlation coefficient was used to evaluate the association between BAI and BF%, as assessed by DEXA. A paired sample t-test was used to test differences in mean BF% obtained with BAI and DEXA methods. To evaluate the concordance between BF% as measured by DEXA and as estimated by BAI, we used Lin’s concordance correlation coefficient and Bland–Altman agreement analysis. The correlation between BF% obtained by DEXA and that estimated by BAI was r = 0.844, p < 0.001. Paired t-test showed a significant mean difference in BF% between methods (BAI = 33.3 ± 6.2 vs. DEXA 39.0 ± 6.1; p < 0.001). The bias of the BAI was −6.0 ± 3.0 BF% (95% CI = −12.0 to 1.0), indicating that the BAI method significantly underestimated the BF% compared to the reference method. Lin’s concordance correlation coefficient was considered stronger (ρc = 0.923, 95% CI = 0.862 to 0.957). In obese adults, BAI presented low agreement with BF% measured by DEXA; therefore, BAI is not recommended for BF% prediction in this overweight/obese sample studied. PMID:27916871

  19. SU-E-I-45: Feasibility for Using Iodine Quantification to Assist Diagnosis in Dual Energy Contrast-Enhanced Digital Mammography

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Y [Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan (China); Lin, Y; Tsai, C [Chang Gung University, Taoyuan, Taiwan (China); Cheung, Y [Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan (China); Chang Gung Memorial Hospital at Taoyuan, Taoyuan, Taiwan (China)

    2015-06-15

    Purpose: The objective of this study is to develop quantitative calibration between image quality indexes and iodine concentration with dual-energy (DE) contrast-enhanced digital mammography (CEDM) techniques and further serve as the assistance for diagnosis. Methods: Custom-made acrylic phantom with dimensions of 24×30 cm{sup 2} simulated breast thickness from 2 to 6 cm was used in the calibration. The phantom contained matrix of four times four holes of 3 mm deep with a diameter of 15 mm for filling contrast agent with area density ranged from 0.1 to 10 mg/cm{sup 2}. All the image acquisitions were performed on a full-field digital mammography system (Senographe Essential, GE) with dual energy acquisitions. Mean pixel value (MPV), and contrast-to-noise ratio (CNR) were used for evaluating the relationship between image quality indexes and iodine concentration. Iodine map and CNR map could further be constructed with these calibration curves applied pixel by pixel utilized MATLAB software. Minimum iodine concentration could also be calculated with the visibility threshold of CNR=5 according the Rose model. Results: When evaluating the DE subtraction images, MPV increased linearly as the iodine concentration increased with all the phantom thickness surveyed (R{sup 2} between 0.989 and 0.992). Lesions with increased iodine uptake could thus be enhanced in the color-encoded iodine maps, and the mean iodine concentration could be obtained through the ROI measurements. As for investigating CNR performance, linear relationships were also shown between the iodine concentration and CNR (R{sup 2} between 0.983 and 0.990). Minimum iodine area density of 1.45, 1.73, 1.80, 1.73 and 1.72 mg/cm{sup 2} for phantom thickness of 2, 3, 4, 5, 6 cm were calculated based on Rose’s visualization criteria. Conclusion: Quantitative calibration between image quality indexes and iodine concentrations may further serving as the assistance for analyzing contrast enhancement for patient

  20. Peering through the glare: using dual-energy CT to overcome the problem of metal artefacts in bone radiology

    Energy Technology Data Exchange (ETDEWEB)

    Coupal, Tyler M. [McMaster University, Michael G. DeGroote School of Medicine, Hamilton, ON (Canada); Mallinson, Paul I.; McLaughlin, Patrick; Nicolaou, Savvas; Munk, Peter L.; Ouellette, Hugue [Vancouver General Hospital, Radiology Department, Vancouver, BC (Canada)

    2014-05-15

    Imaging of patients with large metal implants remains one of the most difficult endeavours for radiologists. This article reviews the theory of dual-energy CT (DECT) and its ability to reduce metal artefact, thus enhancing the diagnostic value of musculoskeletal imaging. The strengths, weaknesses, and alternative applications of DECT, as well as areas requiring further research, will also be reviewed. Currently, DECT stands as the frontier for metal artefact reduction in musculoskeletal imaging. DECT requires no additional radiation and provides significantly enhanced image acquisition. When considered along with its other capabilities, DECT is a promising new tool for musculoskeletal and trauma radiologists. (orig.)

  1. WE-EF-BRA-01: A Dual-Use Optical Tomography System for Small Animal Radiation Research Platform (SARRP)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K; Bin, Z; Wong, J [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins Hospital, Baltimore, MD (United States); He, X; Iordachita, I [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: We develop a novel dual-use configuration for a tri-modality, CBCT/bioluminescence tomography(BLT)/fluorescence tomography(FT), imaging system with the SARRP that can function as a standalone system for longitudinal imaging research and on-board the SARRP to guide irradiation. BLT provides radiation guidance for soft tissue target, while FT offers functional information allowing mechanistic investigations. Methods: The optical assembly includes CCD camera, lens, filter wheel, 3-way mirrors, scanning fiber system and light-tight enclosure. The rotating mirror system directs the optical signal from the animal surface to the camera at multiple projection over 180 degree. The fiber-laser system serves as the external light source for the FT application. Multiple filters are used for multispectral imaging to enhance localization accuracy using BLT. SARRP CBCT provides anatomical information and geometric mesh for BLT/FT reconstruction. To facilitate dual use, the 3-way mirror system is cantilevered in front of the camera. The entire optical assembly is driven by a 1D linear stage to dock onto an independent mouse support bed for standalone application. After completion of on-board optical imaging, the system is retracted from the SARRP to allow irradiation of the mouse. Results: A tissue-simulating phantom and a mouse model with a luminescence light source are used to demonstrate the function of the dual-use optical system. Feasibility data have been obtained based on a manual-docking prototype. The center of mass of light source determined in living mouse with on-board BLT is within 1±0.2mm of that with CBCT. The performance of the motorized system is expected to be the same and will be presented. Conclusion: We anticipate the motorized dual use system provide significant efficiency gain over our manual docking and off-line system. By also supporting off-line longitudinal studies independent of the SARRP, the dual-use system is a highly efficient and cost

  2. Design Concepts for Optimum Energy Use in HVAC Systems.

    Science.gov (United States)

    Electric Energy Association, New York, NY.

    Much of the innovative work in the design and application of heating, ventilating, and air conditioning (HVAC) systems is concentrated on improving the cost effectiveness of such systems through optimizing energy use. One approach to the problem is to reduce a building's HVAC energy demands by designing it for lower heat gains and losses in the…

  3. Reproducibility of trabecular bone score with different scan modes using dual-energy X-ray absorptiometry: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Di Leo, Giovanni [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Pastor Lopez, Maria Juana; Ulivieri, Fabio M. [Servizio di Medicina Nucleare, Ospedale Maggiore, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Milano (Italy); Mai, Alessandro [Universita degli Studi di Milano, Tecniche di Radiologia Medica, per Immagini e Radioterapia, Milano (Italy); Sardanelli, Francesco [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy)

    2014-08-12

    The trabecular bone score (TBS) accounts for the bone microarchitecture and is calculated on dual-energy X-ray absorptiometry (DXA). We estimated the reproducibility of the TBS using different scan modes compared to the reproducibility bone mineral density (BMD). A spine phantom was used with a Hologic QDR-Discovery A densitometer. For each scan mode [fast array, array, high definition (HD)], 25 scans were automatically performed without phantom repositioning; a further 25 scans were performed with phantom repositioning. For each scan, the TBS was obtained. The coefficient of variation (CoV) was calculated as the ratio between standard deviation and mean; percent least significant change (LSC%) as 2.8 x CoV; reproducibility as the complement to 100 % of LSC%. Differences among scan modes were assessed using ANOVA. Without phantom repositioning, the mean TBS (mm{sup -1}) was: 1.352 (fast array), 1.321 (array), and 1.360 (HD); with phantom repositioning, it was 1.345, 1.332, and 1.362, respectively. Reproducibility of the TBS without phantom repositioning was 97.7 % (fast array), 98.3 % (array), and 98.2 % (HD); with phantom repositioning, it was 97.9 %, 98.7 %, and 98.4 %, respectively. LSC% was ≤2.26 %. Differences among scan modes were all statistically significant (p ≤ 0.019). Reproducibility of BMD was 99.1 % with all scan modes, while LSC% was from 0.86 % to 0.91 %. Reproducibility error of the TBS was 2-3-fold higher than that of BMD. Although statistically significant, differences in TBS among scan modes were within the highest LSC%. Thus, the three scan modes can be considered interchangeable. (orig.)

  4. Reproducibility of trabecular bone score with different scan modes using dual-energy X-ray absorptiometry: a phantom study.

    Science.gov (United States)

    Bandirali, Michele; Di Leo, Giovanni; Messina, Carmelo; Pastor Lopez, Maria Juana; Mai, Alessandro; Ulivieri, Fabio M; Sardanelli, Francesco

    2015-04-01

    The trabecular bone score (TBS) accounts for the bone microarchitecture and is calculated on dual-energy X-ray absorptiometry (DXA). We estimated the reproducibility of the TBS using different scan modes compared to the reproducibility bone mineral density (BMD). A spine phantom was used with a Hologic QDR-Discovery A densitometer. For each scan mode [fast array, array, high definition (HD)], 25 scans were automatically performed without phantom repositioning; a further 25 scans were performed with phantom repositioning. For each scan, the TBS was obtained. The coefficient of variation (CoV) was calculated as the ratio between standard deviation and mean; percent least significant change (LSC%) as 2.8 × CoV; reproducibility as the complement to 100 % of LSC%. Differences among scan modes were assessed using ANOVA. Without phantom repositioning, the mean TBS (mm(-1)) was: 1.352 (fast array), 1.321 (array), and 1.360 (HD); with phantom repositioning, it was 1.345, 1.332, and 1.362, respectively. Reproducibility of the TBS without phantom repositioning was 97.7 % (fast array), 98.3 % (array), and 98.2 % (HD); with phantom repositioning, it was 97.9 %, 98.7 %, and 98.4 %, respectively. LSC% was ≤ 2.26 %. Differences among scan modes were all statistically significant (p ≤ 0.019). Reproducibility of BMD was 99.1 % with all scan modes, while LSC% was from 0.86 % to 0.91 %. Reproducibility error of the TBS was 2-3-fold higher than that of BMD. Although statistically significant, differences in TBS among scan modes were within the highest LSC%. Thus, the three scan modes can be considered interchangeable.

  5. Dynamic dual-energy chest radiography: a potential tool for lung tissue motion monitoring and kinetic study.

    Science.gov (United States)

    Xu, Tong; Ducote, Justin L; Wong, Jerry T; Molloi, Sabee

    2011-02-21

    Dual-energy chest radiography has the potential to provide better diagnosis of lung disease by removing the bone signal from the image. Dynamic dual-energy radiography is now possible with the introduction of digital flat-panel detectors. The purpose of this study is to evaluate the feasibility of using dynamic dual-energy chest radiography for functional lung imaging and tumor motion assessment. The dual-energy system used in this study can acquire up to 15 frames of dual-energy images per second. A swine animal model was mechanically ventilated and imaged using the dual-energy system. Sequences of soft-tissue images were obtained using dual-energy subtraction. Time subtracted soft-tissue images were shown to be able to provide information on regional ventilation. Motion tracking of a lung anatomic feature (a branch of pulmonary artery) was performed based on an image cross-correlation algorithm. The tracking precision was found to be better than 1 mm. An adaptive correlation model was established between the above tracked motion and an external surrogate signal (temperature within the tracheal tube). This model is used to predict lung feature motion using the continuous surrogate signal and low frame rate dual-energy images (0.1-3.0 frames per second). The average RMS error of the prediction was (1.1 ± 0.3) mm. The dynamic dual energy was shown to be potentially useful for lung functional imaging such as regional ventilation and kinetic studies. It can also be used for lung tumor motion assessment and prediction during radiation therapy.

  6. Changes in anterior chamber eye during accommodation as assessed using a Dual Scheimpflug system

    Directory of Open Access Journals (Sweden)

    Alberto Domínguez-Vicent

    2014-08-01

    Full Text Available Purpose: To study the changes in anterior chamber depth (ACD, anterior chamber angle (ACA, and pupil diameter (PD during accommodation. Methods: Eighty eyes of 80 subjects, aged 22 to 40 years, were included. The rotating Dual Scheimpflug and a Placido disc system (Galilei G4, Ziemer Ophthalmic Systems AG, Switzerland was used to measure the changes in ACD, ACA, and PD during accommodation. ACD measurement was taken for the central zone and for 4 more positions, each in different orientation (nasal, superior, temporal and inferior, 4 mm away from the centre. ACA was measured for the whole eye as well for the nasal, superior, temporal, and inferior quadrants. These metrics were obtained for various accommodation stimuli, ranging from +1 D to -4 D in 1-D steps. Results: For a given position, the ACD did not vary significantly with accommodation. For the central ACD, the percentage of relative change between far and near vision was -4.11%. The ACA was significantly lower at the inferior, temporal, and superior positions. There was no change in the ACA of the whole eye and that of the nasal orientation. These two eye metrics were significantly lower in the superior-nasal than in the inferior-temporal region. At each vergence studied, the PD decreased significantly with accommodation. The relative change after the -4 D stimulus was -8.13%. Conclusion: ACA and PD varied significantly with accommodation, whereas no such variation of ACD was observed. Further, the anterior chamber was found to be asymmetrical, with the nasal-superior area becoming significantly shallower than the inferior temporal region.

  7. Changes in anterior chamber eye during accommodation as assessed using a Dual Scheimpflug system.

    Science.gov (United States)

    Domínguez-Vicent, Alberto; Monsálvez-Romín, Daniel; Albarrán-Diego, César; Sanchis-Jurado, Vicent; Montés-Micó, Robert

    2014-08-01

    To study the changes in anterior chamber depth (ACD), anterior chamber angle (ACA), and pupil diameter (PD) during accommodation. Eighty eyes of 80 subjects, aged 22 to 40 years, were included. The rotating Dual Scheimpflug and a Placido disc system (Galilei G4, Ziemer Ophthalmic Systems AG, Switzerland) was used to measure the changes in ACD, ACA, and PD during accommodation. ACD measurement was taken for the central zone and for 4 more positions, each in different orientation (nasal, superior, temporal and inferior), 4 mm away from the centre. ACA was measured for the whole eye as well for the nasal, superior, temporal, and inferior quadrants. These metrics were obtained for various accommodation stimuli, ranging from +1 D to -4 D in 1-D steps. For a given position, the ACD did not vary significantly with accommodation. For the central ACD, the percentage of relative change between far and near vision was -4.11%. The ACA was significantly lower at the inferior, temporal, and superior positions. There was no change in the ACA of the whole eye and that of the nasal orientation. These two eye metrics were significantly lower in the superior-nasal than in the inferior-temporal region. At each vergence studied, the PD decreased significantly with accommodation. The relative change after the -4 D stimulus was -8.13%. ACA and PD varied significantly with accommodation, whereas no such variation of ACD was observed. Further, the anterior chamber was found to be asymmetrical, with the nasal-superior area becoming significantly shallower than the inferior temporal region.

  8. Dual-energy micro-CT functional imaging of primary lung cancer in mice using gold and iodine nanoparticle contrast agents: a validation study.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Ashton

    Full Text Available To provide additional functional information for tumor characterization, we investigated the use of dual-energy computed tomography for imaging murine lung tumors. Tumor blood volume and vascular permeability were quantified using gold and iodine nanoparticles. This approach was compared with a single contrast agent/single-energy CT method. Ex vivo validation studies were performed to demonstrate the accuracy of in vivo contrast agent quantification by CT.Primary lung tumors were generated in LSL-Kras(G12D; p53(FL/FL mice. Gold nanoparticles were injected, followed by iodine nanoparticles two days later. The gold accumulated in tumors, while the iodine provided intravascular contrast. Three dual-energy CT scans were performed-two for the single contrast agent method and one for the dual contrast agent method. Gold and iodine concentrations in each scan were calculated using a dual-energy decomposition. For each method, the tumor fractional blood volume was calculated based on iodine concentration, and tumor vascular permeability was estimated based on accumulated gold concentration. For validation, the CT-derived measurements were compared with histology and inductively-coupled plasma optical emission spectroscopy measurements of gold concentrations in tissues.Dual-energy CT enabled in vivo separation of gold and iodine contrast agents and showed uptake of gold nanoparticles in the spleen, liver, and tumors. The tumor fractional blood volume measurements determined from the two imaging methods were in agreement, and a high correlation (R(2 = 0.81 was found between measured fractional blood volume and histology-derived microvascular density. Vascular permeability measurements obtained from the two imaging methods agreed well with ex vivo measurements.Dual-energy CT using two types of nanoparticles is equivalent to the single nanoparticle method, but allows for measurement of fractional blood volume and permeability with a single scan. As

  9. Advanced material separation technique based on dual energy CT scanning

    Science.gov (United States)

    Zamyatin, Alexander A.; Natarajan, Anusha; Zou, Yu

    2009-02-01

    We propose a method for material separation using dual energy data. Our method is suitable to separation of three or more materials. In this work we describe our method and show results of numerical simulation and with real dual-energy data of a head phantom. The proposed method of constructing the material separation map consists of the following steps: Data-domain dual energy decomposition - Vector plot - Density plot - Clustering - Color assignment. Density plots are introduced to allow automatic cluster separation. We use special image processing methods, including Gaussian decomposition, to improve the accuracy of material separation. We also propose using the HSL color model for better visualization and to bring a new dimension in material separation display. We study applications of bone removal and virtual contrast removal. Evaluation shows improved accuracy compared to standard methods.

  10. Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction.

    Science.gov (United States)

    Landry, Guillaume; Gaudreault, Mathieu; van Elmpt, Wouter; Wildberger, Joachim E; Verhaegen, Frank

    2016-03-01

    The goal of this study was to evaluate the noise reduction achievable from dual energy computed tomography (CT) imaging (DECT) using filtered backprojection (FBP) and iterative image reconstruction algorithms combined with increased imaging exposure. We evaluated the data in the context of imaging for brachytherapy dose calculation, where accurate quantification of electron density ρe and effective atomic number Zeff is beneficial. A dual source CT scanner was used to scan a phantom containing tissue mimicking inserts. DECT scans were acquired at 80 kVp/140Sn kVp (where Sn stands for tin filtration) and 100 kVp/140Sn kVp, using the same values of the CT dose index CTDIvol for both settings as a measure for the radiation imaging exposure. Four CTDIvol levels were investigated. Images were reconstructed using FBP and sinogram affirmed iterative reconstruction (SAFIRE) with strength 1,3 and 5. From DECT scans two material quantities were derived, Zeff and ρe. DECT images were used to assign material types and the amount of improperly assigned voxels was quantified for each protocol. The dosimetric impact of improperly assigned voxels was evaluated with Geant4 Monte Carlo (MC) dose calculations for an (125)I source in numerical phantoms. Standard deviations for Zeff and ρe were reduced up to a factor ∼2 when using SAFIRE with strength 5 compared to FBP. Standard deviations on Zeff and ρe as low as 0.15 and 0.006 were achieved for the muscle insert representing typical soft tissue using a CTDIvol of 40 mGy and 3mm slice thickness. Dose calculation accuracy was generally improved when using SAFIRE. Mean (maximum absolute) dose errors of up to 1.3% (21%) with FBP were reduced to less than 1% (6%) with SAFIRE at a CTDIvol of 10 mGy. Using a CTDIvol of 40mGy and SAFIRE yielded mean dose calculation errors of the order of 0.6% which was the MC dose calculation precision in this study and no error was larger than ±2.5% as opposed to errors of up to -4% with FPB. This

  11. Relative quantification of protein-protein interactions using a dual luciferase reporter pull-down assay system.

    Directory of Open Access Journals (Sweden)

    Shuaizheng Jia

    Full Text Available The identification and quantitative analysis of protein-protein interactions are essential to the functional characterization of proteins in the post-proteomics era. The methods currently available are generally time-consuming, technically complicated, insensitive and/or semi-quantitative. The lack of simple, sensitive approaches to precisely quantify protein-protein interactions still prevents our understanding of the functions of many proteins. Here, we develop a novel dual luciferase reporter pull-down assay by combining a biotinylated Firefly luciferase pull-down assay with a dual luciferase reporter assay. The biotinylated Firefly luciferase-tagged protein enables rapid and efficient isolation of a putative Renilla luciferase-tagged binding protein from a relatively small amount of sample. Both of these proteins can be quantitatively detected using the dual luciferase reporter assay system. Protein-protein interactions, including Fos-Jun located in the nucleus; MAVS-TRAF3 in cytoplasm; inducible IRF3 dimerization; viral protein-regulated interactions, such as MAVS-MAVS and MAVS-TRAF3; IRF3 dimerization; and protein interaction domain mapping, are studied using this novel assay system. Herein, we demonstrate that this dual luciferase reporter pull-down assay enables the quantification of the relative amounts of interacting proteins that bind to streptavidin-coupled beads for protein purification. This study provides a simple, rapid, sensitive, and efficient approach to identify and quantify relative protein-protein interactions. Importantly, the dual luciferase reporter pull-down method will facilitate the functional determination of proteins.

  12. Attitude Heading Reference System Using MEMS Inertial Sensors with Dual-Axis Rotation

    Directory of Open Access Journals (Sweden)

    Li Kang

    2014-09-01

    Full Text Available This paper proposes a low cost and small size attitude and heading reference system based on MEMS inertial sensors. A dual-axis rotation structure with a proper rotary scheme according to the design principles is applied in the system to compensate for the attitude and heading drift caused by the large gyroscope biases. An optimization algorithm is applied to compensate for the installation angle error between the body frame and the rotation table’s frame. Simulations and experiments are carried out to evaluate the performance of the AHRS. The results show that the proper rotation could significantly reduce the attitude and heading drifts. Moreover, the new AHRS is not affected by magnetic interference. After the rotation, the attitude and heading are almost just oscillating in a range. The attitude error is about 3° and the heading error is less than 3° which are at least 5 times better than the non-rotation condition.

  13. Attitude heading reference system using MEMS inertial sensors with dual-axis rotation.

    Science.gov (United States)

    Kang, Li; Ye, Lingyun; Song, Kaichen; Zhou, Yang

    2014-09-29

    This paper proposes a low cost and small size attitude and heading reference system based on MEMS inertial sensors. A dual-axis rotation structure with a proper rotary scheme according to the design principles is applied in the system to compensate for the attitude and heading drift caused by the large gyroscope biases. An optimization algorithm is applied to compensate for the installation angle error between the body frame and the rotation table's frame. Simulations and experiments are carried out to evaluate the performance of the AHRS. The results show that the proper rotation could significantly reduce the attitude and heading drifts. Moreover, the new AHRS is not affected by magnetic interference. After the rotation, the attitude and heading are almost just oscillating in a range. The attitude error is about 3° and the heading error is less than 3° which are at least 5 times better than the non-rotation condition.

  14. Study of dual-directional high rate secure communication systems using chaotic multiple-quantum-well lasers

    Institute of Scientific and Technical Information of China (English)

    Yan Sen-Lin

    2007-01-01

    A scheme of synchronized injection multi-quantum-well (MQW) laser system using optical coupling-feedback is presented for performing chaotic dual-directional secure communication. The performance characterization of chaos masking is investigated theoretically, the equation of synchronization demodulation is deduced and its root is also given. Chaos masking encoding with a rate of 5 Gbit/s and a modulation frequency of 1 GHz, chaos modulation with a rate of 0.2 Gbit/s and a modulation frequency of 0.2 GHz and chaos shifting key with a rate of 0.2 Gbit/s are numerically simulated, separately. The ratio of the signal to the absolute synchronous error and the time for achieving synchronous demodulation are analysed in detail. The results illustrate that the system has stronger privacy and good performances so that it can be applied in chaotic dual-directional high rate secure communications.

  15. Dual-homed gateway energy management system based on ZigBee%基于ZigBee双归属网关的能源管理系统

    Institute of Scientific and Technical Information of China (English)

    郭秀才; 尚赛花

    2013-01-01

    为解决城市变化、社区调整带来的重新布线等实际问题,实现对城市能源使用的实时监控管理,利用ZigBee和WCDMA无线网络代替现有的有线通信模式.系统采用ZigBee无线网络和现有的WCDMA无线网络相结合,设计了可靠的双归属模式的WCDZIG网关,实现ZigBee数据信息和WCDMA数据信息二次封包的无障碍传输,实现对各个社区的远程无线连接监控,达到了无人值守、实时集中监控的目的.该系统能够提高监控效率、节约能源,降低综合成本.%In order to solve the practical problems of urban change,community adjustment brought re-wiring,to achieve realtime monitoring and management of urban energy use,the use of ZigBee and WCDMA wireless network to replace the existing wired communication mode.system use a combination of ZigBee wireless networks and the existing WCDMA wireless network,to design reliable dual-homed mode WCDZIG gateway,to achieve barrier-free transmission of secondary packets of the ZigBee data and WCDMA data,each community remote wireless connection monitoring to achieve unattended,real-time centralized monitoring purposes,and ultimately to improve monitoring efficiency,energy conservation,and the purpose of reducing cost.

  16. Added value of 80 kVp images to averaged 120 kVp images in the detection of hepatocellular carcinomas in liver transplantation candidates using dual-source dual-energy MDCT: Results of JAFROC analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Hoon [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Kim, Se Hyung, E-mail: shkim@radcom.snu.ac.kr [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Park, Hee Sun [Department of Radiology, Konkuk University Hospital (Korea, Republic of); Kim, Gi Hyeon [Department of Radiology, Chung-Ang University Hospital (Korea, Republic of); Lee, Jae Young; Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn [Department of Radiology, Seoul National University Hospital (Korea, Republic of); The Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of)

    2011-11-15

    Background: To assess the added value of 80 kVp images to weighted average 120 kVp images for detecting hepatocellular carcinomas (HCCs) using dual-source, dual-energy MDCT. Materials and methods: Forty-one HCCs in 42 patients who underwent liver transplantation (LT) were included. All patients underwent quadruple-phase CT using a 64-row dual-source, dual-energy MDCT with 80 kVp and 140 kVp. For 120 kVp, a linear blending ratio of 0.3 was chosen. Interval reviews for both simulated 120 kVp images without and with pure 80 kVp data were performed independently by two radiologists. They detected HCCs using a 4-point confidence scale. Tumor-to-liver contrast-to-noise ratio (CNR) was calculated and compared between the 80 kVp and simulated 120 kVp images. The additional diagnostic value of 80 kVp images was evaluated by jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis. Results: There were 41 HCCs on pathology and 37 of the 41 HCCs were depicted on CT scan. The mean CNR of the 37 HCCs in late arterial and portal-phase images was significantly better in the 80 kVp images than in 120 kVp images. The average JAFROC figure of merit, however, was not significantly improved when 80 kVp was added. Furthermore, the number of false-positives was significantly increased in reader 1 when adding 80 kVp data. Conclusion: The addition of 80 kVp CT images to simulated 120 kVp images did not significantly improve the detection of HCCs despite of the significantly better CNR of 80 kVp images.

  17. Ventilation imaging of the paranasal sinuses using xenon-enhanced dynamic single-energy CT and dual-energy CT: a feasibility study in a nasal cast

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, Sven F.; Helck, Andreas D.; Reiser, Maximilian F.; Johnson, Thorsten R.C. [Ludwig Maximilians University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Moeller, Winfried; Eickelberg, Oliver [Institute for Lung Biology and Disease (iLBD) and Comprehensive Pneumology Center (CPC), Helmholtz Zentrum Muenchen, Neuherberg, Munich (Germany); Becker, Sven [Ludwig-Maximilians-Universitaet, Department of Otorhinolaryngology - Head and Neck Surgery, Munich (Germany); Schuschnig, Uwe [Pari Pharma GmbH, Graefelfing (Germany)

    2012-10-15

    To show the feasibility of dual-energy CT (DECT) and dynamic CT for ventilation imaging of the paranasal sinuses in a nasal cast. In a first trial, xenon gas was administered to a nasal cast with a laminar flow of 7 L/min. Dynamic CT acquisitions of the nasal cavity and the sinuses were performed. This procedure was repeated with pulsating xenon flow. Local xenon concentrations in the different compartments of the model were determined on the basis of the enhancement levels. In a second trial, DECT measurements were performed both during laminar and pulsating xenon administration and the xenon concentrations were quantified directly. Neither with dynamic CT nor DECT could xenon-related enhancement be detected in the sinuses during laminar airflow. Using pulsating flow, dynamic imaging showed a xenon wash-in and wash-out in the sinuses that followed a mono-exponential function with time constants of a few seconds. Accordingly, DECT revealed xenon enhancement in the sinuses only after pulsating xenon administration. The feasibility of xenon-enhanced DECT for ventilation imaging was proven in a nasal cast. The superiority of pulsating gas flow for the administration of gas or aerosolised drugs to the paranasal sinuses was demonstrated. (orig.)

  18. Potential Energy Savings in Refrigeration Systems Using Optimal Setpoints

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Slot; Thybo, Claus

    2004-01-01

    Energy efficiency of refrigeration systems has gradually been improved with help of control schemes utilizing the more flexible components. This paper proposes an approach in line with this trend, where a suboptimal condenser pressure is found in order to minimize the energy consumption. The obje......Energy efficiency of refrigeration systems has gradually been improved with help of control schemes utilizing the more flexible components. This paper proposes an approach in line with this trend, where a suboptimal condenser pressure is found in order to minimize the energy consumption....... The objective is to give an idea of how this optimization scheme works as well as to show what amount of energy it is possible to save. A steady state model of a simple refrigeration system will be used as a basis for the optimization....

  19. Compressed Air Energy Storage System Control and Performance Assessment Using Energy Harvested Index

    Directory of Open Access Journals (Sweden)

    Hanif SedighNejad

    2014-01-01

    Full Text Available In this paper a new concept for control and performance assessment of compressed air energy storage (CAES systems in a hybrid energy system is introduced. The proposed criterion, based on the concept of energy harvest index (HEI, measures the capability of a storage system to capture renewable energy. The overall efficiency of the CAES system and optimum control and design from the technical and economic point of view is presented. A possible application of this idea is an isolated community with significant wind energy resource. A case study reveals the usefulness of the proposed criterion in design, control and implementation of a small CAES system in a hybrid power system (HPM for an isolated community. Energy harvested index and its effectiveness in increasing the wind penetration rate in the total energy production is discussed.

  20. Testing a dual-systems model of adolescent brain development using resting-state connectivity analyses.

    Science.gov (United States)

    van Duijvenvoorde, A C K; Achterberg, M; Braams, B R; Peters, S; Crone, E A

    2016-01-01

    The current study aimed to test a dual-systems model of adolescent brain development by studying changes in intrinsic functional connectivity within and across networks typically associated with cognitive-control and affective-motivational processes. To this end, resting-state and task-related fMRI data were collected of 269 participants (ages 8-25). Resting-state analyses focused on seeds derived from task-related neural activation in the same participants: the dorsal lateral prefrontal cortex (dlPFC) from a cognitive rule-learning paradigm and the nucleus accumbens (NAcc) from a reward-paradigm. Whole-brain seed-based resting-state analyses showed an age-related increase in dlPFC connectivity with the caudate and thalamus, and an age-related decrease in connectivity with the (pre)motor cortex. nAcc connectivity showed a strengthening of connectivity with the dorsal anterior cingulate cortex (ACC) and subcortical structures such as the hippocampus, and a specific age-related decrease in connectivity with the ventral medial PFC (vmPFC). Behavioral measures from both functional paradigms correlated with resting-state connectivity strength with their respective seed. That is, age-related change in learning performance was mediated by connectivity between the dlPFC and thalamus, and age-related change in winning pleasure was mediated by connectivity between the nAcc and vmPFC. These patterns indicate (i) strengthening of connectivity between regions that support control and learning, (ii) more independent functioning of regions that support motor and control networks, and (iii) more independent functioning of regions that support motivation and valuation networks with age. These results are interpreted vis-à-vis a dual-systems model of adolescent brain development.

  1. Using dual temperature difference two source energy balance model and MODIS data to estimate surface energy fluxes at regional scales in northern latitudes

    Science.gov (United States)

    Guzinski, R.; Anderson, M.; Kustas, W.; Nieto, H.; Sandholt, I.

    2012-04-01

    A Two Source Energy Balance (TSEB) thermal-based modeling scheme has previously been used to successfully estimate surface latent and sensible heat fluxes at regional to continental scales with the help of satellite surface radiometric temperature observations. The Dual Temperature Difference (DTD) model introduced a simple methodology to address the sensitivity of the thermal-based energy balance models to the absolute measurement of land surface temperature (LST), which when derived with the help of satellites can have errors of several degrees. The original DTD model formulation required an early morning LST observation (1 hour after local sunrise) when fluxes were minimal followed by another LST observations later in the morning or afternoon and so was limited in use to data provided by geostationary satellites having high temporal resolution. This, however, made it unsuitable for areas at higher latitudes, such as northern Eurasia and northern North America. In this poster we present a number of modifications to the DTD model which allows it to exploit the day and night LST observations by the MODIS sensor aboard the Terra and Aqua polar orbiting satellites. Firstly, we look at whether taking the first LST observation around the time of Aqua's night overpass, when fluxes are small but not insignificant, would greatly affect the accuracy of the model. Secondly, we consider the issues directly related to using the MODIS sensor to measure the LST. This includes different view zenith angles of the day and night LST observations, the two observations possibly coming from the two different satellites and the accuracy of the instrument itself. We also evaluate two approaches for estimating αPT, the Priestley-Taylor parameter used in the TSEB modeling scheme to estimate heat fluxes of the vegetation canopy, to improve the performance of the model in coniferous and deciduous forests. The first approach estimates αPT based on tree height, while the second uses

  2. Ground Simulation of an Autonomous Satellite Rendezvous and Tracking System Using Dual Robotic Systems

    Science.gov (United States)

    Trube, Matthew J.; Hyslop, Andrew M.; Carignan, Craig R.; Easley, Joseph W.

    2012-01-01

    A hardware-in-the-loop ground system was developed for simulating a robotic servicer spacecraft tracking a target satellite at short range. A relative navigation sensor package "Argon" is mounted on the end-effector of a Fanuc 430 manipulator, which functions as the base platform of the robotic spacecraft servicer. Machine vision algorithms estimate the pose of the target spacecraft, mounted on a Rotopod R-2000 platform, relay the solution to a simulation of the servicer spacecraft running in "Freespace", which performs guidance, navigation and control functions, integrates dynamics, and issues motion commands to a Fanuc platform controller so that it tracks the simulated servicer spacecraft. Results will be reviewed for several satellite motion scenarios at different ranges. Key words: robotics, satellite, servicing, guidance, navigation, tracking, control, docking.

  3. Single-exposure dual-energy computed radiography.

    Science.gov (United States)

    Stewart, B K; Huang, H K

    1990-01-01

    This paper focuses on analysis and development of a single-exposure dual-energy digital radiographic method using computed radiography (Fuji FCR-101 storage phosphor system). A detector sandwich consisting of storage phosphor imaging plates and an interdetector filter is used. The goal of this process is to provide a simple dual-energy method using typical plane-projection radiographic equipment and techniques. This approach exploits the transparency of the storage phosphor plates, using radiographic information that would be otherwise lost, to provide energy selective information essentially as a by-product of the radiographic examination. In order to effectively make use of the large dynamic range of the storage phosphor imaging plates (10,000:1), a computed radiography image reading mode of fixed analog-to-digital converter gain and variable photomultiplier sensitivity provides image data which can be related to relative incident exposure for export to the decomposition algorithm. Scatter rejection requirements necessitated crossed 12:1 grids for a field size of 36 x 36 cm. Optimal technique parameters obtained from computer simulation through minimization of the aluminum and Plexiglas equivalent image uncertainty under conditions of constant absorbed does resulted as: 100 kVp using a 0.15-mm-thick tin (Sn) interdetector filter for the lung field. This yields a surface exposure of 23 mR and a surface absorbed dose of 0.26 mGy for a 23-cm-thick chest. Clinical application in evaluation of the solitary pulmonary nodule is discussed, along with an image set demonstrating this application.

  4. Dual absorptive model and np elastic scattering at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, M.; Fazal-e-Aleem

    1980-06-01

    The most recent measurements of the angular distribution and total cross-sections in np elastic scattering at high energies from 70 to 400 GeV/c have been fitted by using the dual absorptive model. Comparison has also been made with the Kane-Siedl model and the simple Regge pole model.

  5. Nonlinear control for dual quaternion systems

    Science.gov (United States)

    Price, William D.

    The motion of rigid bodies includes three degrees of freedom (DOF) for rotation, generally referred to as roll, pitch and yaw, and 3 DOF for translation, generally described as motion along the x, y and z axis, for a total of 6 DOF. Many complex mechanical systems exhibit this type of motion, with constraints, such as complex humanoid robotic systems, multiple ground vehicles, unmanned aerial vehicles (UAVs), multiple spacecraft vehicles, and even quantum mechanical systems. These motions historically have been analyzed independently, with separate control algorithms being developed for rotation and translation. The goal of this research is to study the full 6 DOF of rigid body motion together, developing control algorithms that will affect both rotation and translation simultaneously. This will prove especially beneficial in complex systems in the aerospace and robotics area where translational motion and rotational motion are highly coupled, such as when spacecraft have body fixed thrusters. A novel mathematical system known as dual quaternions provide an efficient method for mathematically modeling rigid body transformations, expressing both rotation and translation. Dual quaternions can be viewed as a representation of the special Euclidean group SE(3). An eight dimensional representation of screw theory (combining dual numbers with traditional quaternions), dual quaternions allow for the development of control techniques for 6 DOF motion simultaneously. In this work variable structure nonlinear control methods are developed for dual quaternion systems. These techniques include use of sliding mode control. In particular, sliding mode methods are developed for use in dual quaternion systems with unknown control direction. This method, referred to as self-reconfigurable control, is based on the creation of multiple equilibrium surfaces for the system in the extended state space. Also in this work, the control problem for a class of driftless nonlinear systems is

  6. Proposed low-energy absolute calibration of nuclear recoils in a dual-phase noble element TPC using D-D neutron scattering kinematics

    Science.gov (United States)

    Verbus, J. R.; Rhyne, C. A.; Malling, D. C.; Genecov, M.; Ghosh, S.; Moskowitz, A. G.; Chan, S.; Chapman, J. J.; de Viveiros, L.; Faham, C. H.; Fiorucci, S.; Huang, D. Q.; Pangilinan, M.; Taylor, W. C.; Gaitskell, R. J.

    2017-04-01

    We propose a new technique for the calibration of nuclear recoils in large noble element dual-phase time projection chambers used to search for WIMP dark matter in the local galactic halo. This technique provides an in situ measurement of the low-energy nuclear recoil response of the target media using the measured scattering angle between multiple neutron interactions within the detector volume. The low-energy reach and reduced systematics of this calibration have particular significance for the low-mass WIMP sensitivity of several leading dark matter experiments. Multiple strategies for improving this calibration technique are discussed, including the creation of a new type of quasi-monoenergetic neutron source with a minimum possible peak energy of 272 keV. We report results from a time-of-flight-based measurement of the neutron energy spectrum produced by an Adelphi Technology, Inc. DD108 neutron generator, confirming its suitability for the proposed nuclear recoil calibration.

  7. Generating thermal energy and electric power by yourself. Heating system modernization with a mini dual-purpose power plant; Waerme und Strom selbst erzeugen. Heizungsmodernisierung mit Mini-BHKW

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, H. [Powerplus Technologies GmbH, Gera (Germany)

    2008-03-15

    Mini dual-purpose power plants offer many advantages to the customer by means of reduced primary energy consumoption, reduced CO{sub 2} emission and considerable savings of energy costs. The following contribution describes the balance in the one-family house of the Gross family and what heating systems master craftsman Keijo Sprogoetook into consideration when he executed this modernization task. (orig.)

  8. Deriving concentrations of oxygen and carbon in human tissues using single- and dual-energy CT for ion therapy applications

    Science.gov (United States)

    Landry, Guillaume; Parodi, Katia; Wildberger, Joachim E.; Verhaegen, Frank

    2013-08-01

    Dedicated methods of in-vivo verification of ion treatment based on the detection of secondary emitted radiation, such as positron-emission-tomography and prompt gamma detection require high accuracy in the assignment of the elemental composition. This especially concerns the content in carbon and oxygen, which are the most abundant elements of human tissue. The standard single-energy computed tomography (SECT) approach to carbon and oxygen concentration determination has been shown to introduce significant discrepancies in the carbon and oxygen content of tissues. We propose a dual-energy CT (DECT)-based approach for carbon and oxygen content assignment and investigate the accuracy gains of the method. SECT and DECT Hounsfield units (HU) were calculated using the stoichiometric calibration procedure for a comprehensive set of human tissues. Fit parameters for the stoichiometric calibration were obtained from phantom scans. Gaussian distributions with standard deviations equal to those derived from phantom scans were subsequently generated for each tissue for several values of the computed tomography dose index (CTDIvol). The assignment of %weight carbon and oxygen (%wC,%wO) was performed based on SECT and DECT. The SECT scheme employed a HU versus %wC,O approach while for DECT we explored a Zeff versus %wC,O approach and a (Zeff, ρe) space approach. The accuracy of each scheme was estimated by calculating the root mean square (RMS) error on %wC,O derived from the input Gaussian distribution of HU for each tissue and also for the noiseless case as a limiting case. The (Zeff, ρe) space approach was also compared to SECT by comparing RMS error for hydrogen and nitrogen (%wH,%wN). Systematic shifts were applied to the tissue HU distributions to assess the robustness of the method against systematic uncertainties in the stoichiometric calibration procedure. In the absence of noise the (Zeff, ρe) space approach showed more accurate %wC,O assignment (largest error of

  9. WE-G-BRF-05: Feasibility of Markerless Motion Tracking Using Dual Energy Cone Beam Computed Tomography (DE-CBCT) Projections

    Energy Technology Data Exchange (ETDEWEB)

    Panfil, J; Patel, R; Surucu, M; Roeske, J [Loyola University Medical Center, Maywood, IL (United States)

    2014-06-15

    Purpose: To compare markerless template-based tracking of lung tumors using dual energy (DE) cone-beam computed tomography (CBCT) projections versus single energy (SE) CBCT projections. Methods: A RANDO chest phantom with a simulated tumor in the upper right lung was used to investigate the effectiveness of tumor tracking using DE and SE CBCT projections. Planar kV projections from CBCT acquisitions were captured at 60 kVp (4 mAs) and 120 kVp (1 mAs) using the Varian TrueBeam and non-commercial iTools Capture software. Projections were taken at approximately every 0.53° while the gantry rotated. Due to limitations of the phantom, angles for which the shoulders blocked the tumor were excluded from tracking analysis. DE images were constructed using a weighted logarithmic subtraction that removed bony anatomy while preserving soft tissue structures. The tumors were tracked separately on DE and SE (120 kVp) images using a template-based tracking algorithm. The tracking results were compared to ground truth coordinates designated by a physician. Matches with a distance of greater than 3 mm from ground truth were designated as failing to track. Results: 363 frames were analyzed. The algorithm successfully tracked the tumor on 89.8% (326/363) of DE frames compared to 54.3% (197/363) of SE frames (p<0.0001). Average distance between tracking and ground truth coordinates was 1.27 +/− 0.67 mm for DE versus 1.83+/−0.74 mm for SE (p<0.0001). Conclusion: This study demonstrates the effectiveness of markerless template-based tracking using DE CBCT. DE imaging resulted in better detectability with more accurate localization on average versus SE. Supported by a grant from Varian Medical Systems.

  10. Good interrater reliability of a new grading system in detecting traumatic bone marrow lesions in the knee by dual energy CT virtual non-calcium images

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Jian-xin; Wang, Yi-min [Department of Radiology, Wuhan 161th Hospital, 68 Huangpu Road, Wuhan 430010 (China); Kong, Xiang-quan, E-mail: kxq2013@tom.com [Department of Radiology, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022 (China); Yang, Cheng; Wang, Peng [Department of Radiology, Wuhan 161th Hospital, 68 Huangpu Road, Wuhan 430010 (China)

    2015-06-15

    Highlights: • We use DECT image to show traumatic bone marrow lesions (BMLs). • Traumatic BMLs were assessed with quantitative and qualitative analysis. • Time interval between CT scanning and MRI was only 1.8 ± 0.6 days. • All patients have no obviously fracture, and bone bruise was diagnosed. - Abstract: Objective: To evaluate the capacity of dual-energy computed tomography (DECT) virtual non-calcium (VNCa) images in detecting post-traumatic bone marrow lesions (BMLs) in the knee with a new grading system. Methods: DECT and magnetic resonance (MR) imaging were used to examine acute trauma of the knee in 32 patients. VNCa images were generated by dual-energy subtraction of calcium, and the lower end of the femur and upper end of the tibia each were divided into six regions for grading of bone marrow by two musculoskeletal radiologists using a four-grading system (Grade 4, very obvious lesions; Grade 3, relatively obvious lesions; Grade 2, slight or suspicious lesion on VNCa image and mild lesion on MR image; Grade 1, normal bone marrow). CT values were obtained in the BMLs. MR images were used as the reference standard. Grade 3–4 bone marrow was regarded as a positive result to evaluate the performance of VNCa images in detecting traumatic BMLs in the knee, and receiver operating characteristic (ROC) curve analysis of VNCa images for detection of knee BMLs was performed based on CT value of the bone marrow. Results: Bone marrow rating by the two radiologists showed very good consistency (κ = 0.850 and 0.869 for VNCa and MR images, respectively). VNCa and MR images had good consistency (κ = 0.799 for lower end of the femur; κ = 0.659 for upper end of the tibia). When Grade 3–4 bone marrow was regarded as a positive result, the sensitivity, specificity, positive predictive value, and negative predictive value of VNCa images for detection of BMLs in the lower end of the femur were 73.5%, 98.6%, 94.7%, and 91.6%, respectively, and the values in the

  11. Use of Danish Heat Atlas and energy system models for exploring renewable energy scenarios

    DEFF Research Database (Denmark)

    Petrovic, Stefan; Karlsson, Kenneth Bernard

    2013-01-01

    networks in relation with significant heat saving measures that are capital intensive infrastructure investments require highly detailed decision - support tools. The Heat Atlas for Denmark provides a highly detailed database and includes heat demand and possible heat savings for about 2.5 million...... buildings with associated costs included. Energy systems modelling tools that incorporate economic, environmental, energy and engineering analysis of future energy systems are considered crucial for quantitative assessment of transitional scenarios towards future milestones, such as (i) EU 2020 goals...... of reducing greenhouse gas emissions, increasing share of renewable energy and improving energy efficiency and (ii) Denmark’s 2050 goals of covering entire energy supply by renewable energy. Optimization and simulation energy system models are currently used in Denmark. The present paper tends to provide...

  12. Use of hybrid renewable energy systems for small communities

    Directory of Open Access Journals (Sweden)

    Bandoc Georgeta

    2016-01-01

    Full Text Available The purpose of this article is to present how the sizing of a hybrid renewable energy system is done for a community of three hundred and five households located in a Delta, starting from the optimization of hybrid energy system for a single household. The methodology used in solving this problem is based on multiple options. The first option consists in determined energy needs, maximum power consumption in cold season and in adapting the solution for the production of electricity by a hybrid plant. The second option consists of energy needs resulted in average consumption of electricity in warm season and in adapting the solution for the production of electricity from a hybrid plant. In conjunction with the demand for electricity for the entire community one will get energy demand by aggregating household level (kWh/household. The novelty of this approach lies in the method used by these hybrid systems for obtaining electricity in small communities, isolated from this case study. Based on the results obtained the method can be expanded the implementation of these projects that use hybrid renewable energy systems.

  13. Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Munich Univ. (Germany). Dept. of Medical Physics; Gaudreault, Mathieu [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Laval Univ., QC (Canada). Dept. de Radio-Oncologie et Centre de Recherche en Cancerologie; Laval Univ., QC (Canada). Dept. de Physique, de Genie Physique et d' Optique; Elmpt, Wouter van [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); Wildberger, Joachim E. [Maastricht University Medical Center (Netherlands). Dept. of Radiology; Verhaegen, Frank [Maastricht University Medical Center (Netherlands). Dept. of Radiation Oncology (MAASTRO); McGill Univ. Montreal, QC (Canada). Dept. of Oncology

    2016-05-01

    The goal of this study was to evaluate the noise reduction achievable from dual energy computed tomography (CT) imaging (DECT) using filtered backprojection (FBP) and iterative image reconstruction algorithms combined with increased imaging exposure. We evaluated the data in the context of imaging for brachytherapy dose calculation, where accurate quantification of electron density ρ{sub e} and effective atomic number Z{sub eff} is beneficial. A dual source CT scanner was used to scan a phantom containing tissue mimicking inserts. DECT scans were acquired at 80 kVp/140Sn kVp (where Sn stands for tin filtration) and 100 kVp/140Sn kVp, using the same values of the CT dose index CTDI{sub vol} for both settings as a measure for the radiation imaging exposure. Four CTDI{sub vol} levels were investigated. Images were reconstructed using FBP and sinogram affirmed iterative reconstruction (SAFIRE) with strength 1,3 and 5. From DECT scans two material quantities were derived, Z{sub eff} and ρ{sub e}. DECT images were used to assign material types and the amount of improperly assigned voxels was quantified for each protocol. The dosimetric impact of improperly assigned voxels was evaluated with Geant4 Monte Carlo (MC) dose calculations for an {sup 125}I source in numerical phantoms. Standard deviations for Z{sub eff} and ρ{sub e} were reduced up to a factor ∝2 when using SAFIRE with strength 5 compared to FBP. Standard deviations on Z{sub eff} and ρ{sub e} as low as 0.15 and 0.006 were achieved for the muscle insert representing typical soft tissue using a CTDI{sub vol} of 40 mGy and 3 mm slice thickness. Dose calculation accuracy was generally improved when using SAFIRE. Mean (maximum absolute) dose errors of up to 1.3% (21%) with FBP were reduced to less than 1% (6%) with SAFIRE at a CTDI{sub vol} of 10 mGy. Using a CTDI{sub vol} of 40mGy and SAFIRE yielded mean dose calculation errors of the order of 0.6% which was the MC dose calculation precision in this study and

  14. RF Design and Predicted Performance for a Future 34-meter Shaped Dual-reflector Antenna System Using the Common Aperture X-S Feedhorn

    Science.gov (United States)

    Williams, W. F.

    1983-01-01

    The Networks Consolidation Program (NCP) will utilize 34-meter shaped dual-reflector Cassegrain antennas. The shaping calculations, the X/S-band feedhorn to be used, and the predicted RF performance of this antenna system are discussed.

  15. Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaowei; Servaes, Sabah; Darge, Kassa [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, The Perelman School of Medicine, Philadelphia, PA (United States); McCullough, William P. [University of Virginia Health System, Department of Radiology and Medical Imaging, Charlottesville, VA (United States); Mecca, Patricia [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2016-11-15

    Dual-energy CT technology is available on scanners from several vendors and offers significant advantages over classic single-energy CT technology in multiple clinical applications. Many studies have detailed dual-energy CT applications in adults and several have evaluated the relative radiation dose performance of dual-energy CT in adult imaging. However, little has been published on dual-energy CT imaging in the pediatric population, and the relative dose performance of dual-energy CT imaging in the pediatric population is not well described. When evaluating dual-energy CT technology for implementation into a routine clinical pediatric imaging practice, the radiation dose implications must be considered, and when comparing relative CT dose performance, image quality must also be evaluated. Therefore the purpose of this study is to develop dual-energy CT scan protocols based on our optimized single-energy scan protocols and compare the dose. We scanned the head, chest and abdomen regions of pediatric-size anthropomorphic phantoms with contrast inserts, using our optimized single-energy clinical imaging protocols on a Siemens Flash {sup registered} CT scanner. We then scanned the phantoms in dual-energy mode using matching image-quality reference settings. The effective CT dose index volume (CTDI{sub vol}) of the scans was used as a surrogate for relative dose in comparing the single- and dual-energy scans. Additionally, we evaluated image quality using visual assessment and contrast-to-noise ratio. Dual-energy CT scans of the head and abdomen were dose-neutral for all three phantoms. Dual-energy CT scans of the chest showed a relative dose increase over the single-energy scan for 1- and 5-year-old child-based age-equivalent phantoms, ranging 11-20%. Quantitative analysis of image quality showed no statistically significant difference in image quality between the single-energy and dual-energy scans. There was no clinically significant difference in image quality by

  16. Increasing RES Penetration and Security of Energy Supply by Use of Energy Storages and Heat Pumps in Croatian Energy System

    DEFF Research Database (Denmark)

    Krajačić, Goran; Mathiesen, Brian Vad; Duić, Neven;

    2010-01-01

    In this paper integration of wind power generation into the Croatian electricity supply is analysed using available technologies. The starting point is a model of the energy system in Croatia in 2007. Comprehensive hour-by-hour energy system analyses are conducted of a complete system meeting...... electricity, heat and transport demands, and including renewable energy, power plants, and combined heat and power production (CHP) for district heating. Using the 2007 energy system the wind power share is increased by two energy storage options: Pumped hydro and heat pumps in combination with heat storages...... with specific regulation of power system could additionally increase wind penetration for 0.37 TWh. Hence, with the current technologies installed in the Croatian energy system the installed pumped hydro-plant may facilitate more than 10% wind power in the electricity system. Large-scale integration of wind...

  17. Energy-Efficient Building HVAC Control Using Hybrid System LBMPC

    CERN Document Server

    Aswani, Anil; Taneja, Jay; Krioukov, Andrew; Culler, David; Tomlin, Claire

    2012-01-01

    Improving the energy-efficiency of heating, ventilation, and air-conditioning (HVAC) systems has the potential to realize large economic and societal benefits. This paper concerns the system identification of a hybrid system model of a building-wide HVAC system and its subsequent control using a hybrid system formulation of learning-based model predictive control (LBMPC). Here, the learning refers to model updates to the hybrid system model that incorporate the heating effects due to occupancy, solar effects, outside air temperature (OAT), and equipment, in addition to integrator dynamics inherently present in low-level control. Though we make significant modeling simplifications, our corresponding controller that uses this model is able to experimentally achieve a large reduction in energy usage without any degradations in occupant comfort. It is in this way that we justify the modeling simplifications that we have made. We conclude by presenting results from experiments on our building HVAC testbed, which s...

  18. Reducing airflow energy use in multiple zone vav systems

    Science.gov (United States)

    Tukur, Ahmed Gidado

    Variable Air Volume (VAV) systems are the most popular HVAC systems in commercial buildings. VAV systems are designed to deliver airflows at design conditions which only occur for a few hours in a year. Minimizing energy use in VAV systems requires reducing the amount of airflow delivered through the system at part load conditions. Air Handling Unit (AHU) fans are the major drivers of airflow in VAV systems and installing a Variable Frequency Drive (VFD) is the most common method of regulating airflow in VAV systems. A VFD drive does not necessarily save energy without use of an appropriate control strategy. Static pressure reset (SPR) is considered to be the most energy efficient control strategy for AHU fans with VFDs installed. The implementation of SPR however has many challenges; for example, rogue zones--zones which have faulty sensors or failed controls and actuators, system dynamics like hunting and system diversity. By investigating the parameters associated with the implementation of SPR in VAV systems, a new, improved, more stable SPR algorithm was developed and validated. This approach was further improved using Fault Detection and Diagnostics (FDD) to eliminate rogue zones. Additionally, a CO2-Demand Control Ventilation (DCV) based minimum airflow control was used to further reduce ventilation airflow and save more energy from SPR. Energy savings ranging from 25% to 51% were recorded in actual buildings with the new SPR algorithm. Finally, a methodology that utilizes historical VAV data was developed to estimate the potential savings that could be realized using SPR. The approach employed first determines an effective system loss coefficient as a function of mean damper position using the historical duct static pressure, VAV damper positions and airflows. Additionally, the historical data is used to identify the maximum mean duct damper position realizable as a result of insuring a sufficient number of VAVs are fully open at any time. Savings are

  19. Clinical eraluation of dual-source CT enterography using dual-energy rirtual non-enhanced technique%双源 CT 小肠造影双能量虚拟平扫的临床评估

    Institute of Scientific and Technical Information of China (English)

    邓丽萍; 史晓喆; 章士正; 张峭巍

    2014-01-01

    -processed with Liver-VNC software.Using CNCT as a standard,the image quality of VNCT images were evaluated and scored with 1~4 grade scoring system (the higher score indicated better image quality:4 scores means per-fect,1 score means unsatisfactory for diagnosis).The radiation dose of CNCT,arterial and venous phase CECT was com-pared.Results:Of 39 patients,there were 25 cases with lesions and 14 cases of normal.Compared with CNCT images,all the lesions were also detected accurately by VNCT images,and there was no significant difference of size and extent of lesions between CNCT and VNCT.The scores of VNCT images were all higher than 2,there was no significant statistic difference between the score of two doctors,and the image quality of VNCT images met the requirement of diagnosis.The average dose length product (DLP)of conventional non-enhanced CT,arterial and venous phase CECT were (283.8750±57.1195), (289.3750±53.1543 )and (301.2917 ± 55.3346 )mGy · cm respectively,with no statistic difference (F = 0.615,P =0.544).Conclusion:Dual energy CT virtual non-enhanced images may replace true non-enhanced images in CT enterography and then can reduce radiation dose of examination.

  20. Power Flow Control of a Dual-Input Interleaved Buck/Boost Converter with Galvanic Isolation for Renewable Energy Systems

    DEFF Research Database (Denmark)

    Mira Albert, Maria del Carmen; Zhang, Zhe; Knott, Arnold

    2015-01-01

    DC microgrids or nanogrids have attracted increasing research interest in recent years. Therefore, as a critical component, dc-dc converters with multiple inputs are required. In this paper, a dual-input interleaved buck/boost converter is proposed and its corresponding power flow control methods...

  1. Theoretical and applied research on bistable dual-piezoelectric-cantilever vibration energy harvesting toward realistic ambience

    Science.gov (United States)

    Gao, Y.; Leng, Y.; Javey, A.; Tan, D.; Liu, J.; Fan, S.; Lai, Z.

    2016-11-01

    Pink noise, which is similar to realistic ambient noise, is normally used to simulate ambience where a piezoelectric energy harvesting system (PEHS) is set up. However, pink noise with standard spectral representation can only be used to simulate excitations assumed to possess constant intensity, whereas realistic ambient noise normally appears with a random spectrum and varying intensity in terms of different locations and time. The output performance of conventional bistable magnetic repulsive energy harvesters is significantly affected by the ambience intensity. Considering this fact, a model bistable dual-piezoelectric-cantilever energy harvester (DPEH) is developed in this study to achieve optimal broadband energy harvesting under a varying-intensity realistic circumstance. We utilized various realistic ambient conditions as excitations to obtain the DPEH energy harvesting performance for theoretical and applied study. The elastically supported PEHS has been proven to be more adaptive to realistic ambience with significant or medium intensity variation, but is less qualified for realistic ambience with constant intensity compared with the rigidly supported PEHS (RPEHS). Fortunately, the dual-piezoelectric-cantilever energy harvesting system is superior to the RPEHS under all circumstances because the dual-piezoelectric cantilevers are efficiently utilized for electromechanical energy conversion to realize optimal energy harvesting.

  2. ENERGY MANAGEMENT OF PHOTOVOLTAIC SYSTEMS USING FUEL CELLS

    Directory of Open Access Journals (Sweden)

    Cristian MIRON

    2016-11-01

    Full Text Available Renewable energy generators show an accelerated growth both in terms of production wise, as well as in research fields. Focusing only on photovoltaic panels, the generated energy has the disadvantage of being strongly oscillatory in evolution. The classical solution is to create a network between photovoltaic farms spanning on large distances, in order to share the total energy before sending it to the clients. A solution that was recently proposed is going to use hydrogen in order to store the energy surplus. Fuel Cells (FCs represent energy generators whose energy vector is usually hydrogen. These have already started the transition from the laboratory context towards commercialization. Due to their high energy density, as well as their theoretical infinite storage capacity through hydrogen, configurations based on electrolyzers and FCs are seen as high potential storage systems, both for vehicle and for stationary applications. Therefore, a study on such distributed control systems is of high importance. This paper analyses the existing solutions, with emphasis on a particular case where a supervisory system is developed and tested in a specialised simulation software.

  3. Clinical use of a portable dual microscope system for smartphone (Conference Presentation)

    Science.gov (United States)

    Kurachi, Cristina; Brognara, Gabriel; Gómez-García, Pablo A.; Carbinatto, Fernanda; Silva, Eduardo V.; Lombardi, Wellington; Inada, Natália M.; Bagnato, Vanderlei S.

    2016-03-01

    Cervical cancer is still one of the most relevant women cancer types, since the 5-year survival rate is of only around 68%. Prevention and early diagnosis are the best strategies to improve cervical cancer prognosis. Conventional diagnosis procedure in Gynecology is mainly based on the macroscopic clinical evaluation, Pap smear cytology, and biopsy, if needed. A portable microscope with dual configuration and its use for diagnosis in Gynecology is investigated. The microscope has interchangeable parts that allow its use for cytopathology smear samples or in situ endoscopic tissue interrogation, both using acriflavine as a nuclei marker. Patients of the Women Ambulatory of the School of Medicine (UNIARA, Araraquara, Brazil) were interrogated during the colposcopy examination. The cervix was initially cleaned using an acetic acid solution, and a 0.05% (wt/vol) acriflavine in saline solution was topically applied at the tissue surface using a cotton swab. Microendoscopy images were taken from clinically normal cervix mucosa and from detected lesions. An image processing is performed to evaluate the cell nuclei morphology and the cytoplasm/nuclei ratio. The Pap smear results and the histology analyses are taken as gold standard for the diagnosis. Preliminary results in 5 patients demonstrated the potential use of our microscope at the clinical setting.

  4. Differentiation of neoplastic from bland macroscopic portal vein thrombi using dual-energy spectral CT imaging: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Li Jun; Zhu, Jiong; Zhuang, Zhi Guo; Xu, Jian Rong [Shanghai Jiaotong University School of Medicine, Department of Radiology, Renji Hospital, Shanghai (China); Xia, Qiang [Shanghai Jiaotong University School of Medicine, Department of Hepatic Surgery, Renji Hospital, Shanghai (China); Cheng, Yu.Fan [Chang Gung University College of Medicine, Liver Transplantation Program, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung (China); Li, Jian Ying [GE Healthcare China, CT Imaging Research Center, Beijing (China)

    2012-10-15

    To assess the feasibility and value of dual-energy spectral computed tomography (DESCT) imaging for differentiating neoplastic from bland macroscopic portal vein (PV) thrombi. Computed tomography (CT) images of 44 patients with macroscopic PV thrombus (bland group, n = 16; neoplastic group, n = 28) were reviewed. Iodine-based material decomposition images in the portal venous phase were reconstructed to compare the iodine indices between groups, including thrombus iodine density (I{sub T}), thrombus-aorta iodine density ratio (I{sub T}/I{sub A}), and thrombus-PV iodine density ratio (I{sub T}/I{sub P}). Differential diagnostic performances of DESCT were calculated in the subgroup of 21 patients with histopathological evidence (bland group, n = 12; neoplastic group, n = 9). The iodine indices of the neoplastic group were significantly higher than those in the bland group (P < 0.001). A threshold I{sub T} of 1.14 mg/mL, I{sub T}/I{sub A} of 0.17, and I{sub T}/I{sub P} of 0.17 in the portal venous phase yielded 100 %, 88.9 %, and 100 % sensitivity, and 91.7 %, 91.7 %, and 83.3 % specificity, respectively, in differentiating neoplastic from bland PV thrombi. DESCT imaging with quantification of thrombus iodine density in the portal venous phase appears to be a promising new method for distinguishing neoplastic from bland macroscopic PV thrombi. (orig.)

  5. Development of a patch type embedded cardiac function monitoring system using dual microprocessor for arrhythmia detection in heart disease patient.

    Science.gov (United States)

    Jang, Yongwon; Noh, Hyung Wook; Lee, I B; Jung, Ji-Wook; Song, Yoonseon; Lee, Sooyeul; Kim, Seunghwan

    2012-01-01

    A patch type embedded cardiac function monitoring system was developed to detect arrhythmias such as PVC (Premature Ventricular Contraction), pause, ventricular fibrillation, and tachy/bradycardia. The overall system is composed of a main module including a dual processor and a Bluetooth telecommunication module. The dual microprocessor strategy minimizes power consumption and size, and guarantees the resources of embedded software programs. The developed software was verified with standard DB, and showed good performance.

  6. Dual-energy perfusion-CT of pancreatic adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Klauß, M., E-mail: miriam.klauss@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Stiller, W., E-mail: wolfram.stiller@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Pahn, G., E-mail: gregor.pahn@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Fritz, F., E-mail: franzi.fritz@cegug.org [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Kieser, M., E-mail: meinhard.kieser@med.uni-heidelberg.de [University of Heidelberg, Inst. of Medical Biometry and Informatics, Im Neuenheimer Feld 305, 69120 Heidelberg (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Surgery, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Kauczor, H.U., E-mail: hans-ulrich.kauczor@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Grenacher, L., E-mail: lars.grenacher@med.uni-heidelberg.de [University of Heidelberg, Dpt. of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany)

    2013-02-15

    Purpose: To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. Materials and methods: 24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV{sub p}, 140 kV{sub p}, and weighted average (linearly blended M0.3) 120 kV{sub p}-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. Results: In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV{sub p}-equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min{sup −1} vs. 0.91 ± 0.04 min{sup −1} (p < 0.0001), 0.5 ± 0.07 *0.5 min{sup −1} vs. 0.67 ± 0.05 *0.5 min{sup −1} (p = 0.06) and 0.49 ± 0.07 min{sup −1} vs. 1.28 ± 0.11 min{sup −1} (p < 0.0001). Compared with 80 and 140 kV{sub p} the standard deviations of the kV{sub p}120 kV{sub p}-equivalent values were manifestly smaller. Conclusion: Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV{sub p} in combination with the noise reduction at 140 kV{sub p}. Therefore using dual-energy perfusion data could improve the delineation

  7. Proposed low-energy absolute calibration of nuclear recoils in a dual-phase noble element TPC using D-D neutron scattering kinematics

    CERN Document Server

    Verbus, J R; Malling, D C; Genecov, M; Ghosh, S; Moskowitz, A G; Chan, S; Chapman, J J; de Viveiros, L; Faham, C H; Fiorucci, S; Huang, D Q; Pangilinan, M; Taylor, W C; Gaitskell, R J

    2016-01-01

    We propose a new technique for the calibration of nuclear recoils in large noble element dual-phase time projection chambers used to search for WIMP dark matter in the local galactic halo. This technique provides an $\\textit{in situ}$ measurement of the low-energy nuclear recoil response of the target media using the measured scattering angle between multiple neutron interactions within the detector volume. The low-energy reach and reduced systematics of this calibration have particular significance for the low-mass WIMP sensitivity of several leading dark matter experiments. Multiple strategies for improving this calibration technique are discussed, including the creation of a new type of quasi-monoenergetic 272 keV neutron source. We report results from a time-of-flight based measurement of the neutron energy spectrum produced by an Adelphi Technology, Inc. DD108 neutron generator, confirming its suitability for the proposed nuclear recoil calibration.

  8. Dual-energy lung perfusion computed tomography: a novel pulmonary functional imaging method.

    Science.gov (United States)

    Thieme, Sven F; Johnson, Thorsten R C; Reiser, Maximilian F; Nikolaou, Konstantin

    2010-08-01

    Dual-energy computed tomography (DECT) can be used for visualization of pulmonary microvascular contrast material distribution, representing regional perfusion. It is performed as DECT angiography and allows for the reconstruction of morphologic images as well as of "perfusion maps." The authors of previous studies have shown its potential to reliably depict perfusion defects, mainly in the context of pulmonary embolism. Also in the diagnostic work-up of other pulmonary diseases, there might be additional functional information provided by dual-energy acquisition techniques. This review focuses on the physical and technical background and the potential clinical value of pulmonary DECT. Technical improvements of a second-generation dual-source CT system are elucidated.

  9. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  10. Hybrid energy harvesting systems, using piezoelectric elements and dielectric polymers

    Science.gov (United States)

    Cornogolub, Alexandru; Cottinet, Pierre-Jean; Petit, Lionel

    2016-09-01

    Interest in energy harvesting applications has increased a lot during recent years. This is especially true for systems using electroactive materials like dielectric polymers or piezoelectric materials. Unfortunately, these materials despite multiple advantages, present some important drawbacks. For example, many dielectric polymers demonstrated high energy densities; they are cheap, easy to process and can be easily integrated in many different structures. But at the same time, dielectric polymer generators require an external energy supply which could greatly compromise their autonomy. Piezoelectric systems, on the other hand, are completely autonomous and can be easily miniaturized. However, most common piezoelectric materials present a high rigidity and are brittle by nature and therefore their integration could be difficult. This paper investigates the possibility of using hybrid systems combining piezoelectric elements and dielectric polymers for mechanical energy harvesting applications and it is focused mainly on the problem of electrical energy transfer. Our objective is to show that such systems can be interesting and that it is possible to benefit from the advantages of both materials. For this, different configurations were considered and the problem of their optimization was addressed. The experimental work enabled us to prove the concept and identify the main practical limitations.

  11. Prediction of Android and Gynoid Body Adiposity via a Three-dimensional Stereovision Body Imaging System and Dual-Energy X-ray Absorptiometry.

    Science.gov (United States)

    Lee, Jane J; Freeland-Graves, Jeanne H; Pepper, M Reese; Stanforth, Philip R; Xu, Bugao

    2015-01-01

    Current methods for measuring regional body fat are expensive and inconvenient compared to the relative cost-effectiveness and ease of use of a stereovision body imaging (SBI) system. The primary goal of this research is to develop prediction models for android and gynoid fat by body measurements assessed via SBI and dual-energy x-ray absorptiometry (DXA). Subsequently, mathematical equations for prediction of total and regional (trunk, leg) body adiposity were established via parameters measured by SBI and DXA. A total of 121 participants were randomly assigned into primary and cross-validation groups. Body measurements were obtained via traditional anthropometrics, SBI, and DXA. Multiple regression analysis was conducted to develop mathematical equations by demographics and SBI assessed body measurements as independent variables and body adiposity (fat mass and percentage fat) as dependent variables. The validity of the prediction models was evaluated by a split sample method and Bland-Altman analysis. The R(2) of the prediction equations for fat mass and percentage body fat were 93.2% and 76.4% for android and 91.4% and 66.5% for gynoid, respectively. The limits of agreement for the fat mass and percentage fat were -0.06 ± 0.87 kg and -0.11% ± 1.97% for android and -0.04 ± 1.58 kg and -0.19% ± 4.27% for gynoid. Prediction values for fat mass and percentage fat were 94.6% and 88.9% for total body, 93.9% and 71.0% for trunk, and 92.4% and 64.1% for leg, respectively. The three-dimensional (3D) SBI produces reliable parameters that can predict android and gynoid as well as total and regional (trunk, leg) fat mass.

  12. Brown adipose tissue in humans: detection and functional analysis using PET (positron emission tomography), MRI (magnetic resonance imaging), and DECT (dual energy computed tomography).

    Science.gov (United States)

    Borga, Magnus; Virtanen, Kirsi A; Romu, Thobias; Leinhard, Olof Dahlqvist; Persson, Anders; Nuutila, Pirjo; Enerbäck, Sven

    2014-01-01

    If the beneficial effects of brown adipose tissue (BAT) on whole body metabolism, as observed in nonhuman experimental models, are to be translated to humans, tools that accurately measure how BAT influences human metabolism will be required. This chapter discusses such techniques, how they can be used, what they can measure and also some of their limitations. The focus is on detection and functional analysis of human BAT and how this can be facilitated by applying advanced imaging technology such as positron emission tomography, magnetic resonance imaging, and dual energy computed tomography. © 2014 Elsevier Inc. All rights reserved.

  13. Eating energy. Identifying possibilities for reduced energy use in the future food supply system

    Energy Technology Data Exchange (ETDEWEB)

    Wallgren, Christine; Hoejer, Mattias [Division of Environmental Strategies Research-fms, Department of Urban Planning and Environment, Royal Institute of Technology, Stockholm (Sweden)

    2009-12-15

    This paper explores the possibilities for reducing future energy use for eating to a sustainable level. A backcasting approach is used to generate an image of the future where energy use for eating is 60% lower in 2050 than in 2000. The currently known potential to reduce energy use in the food supply system for producing, transporting, storing, cooking and eating food is explored and described in terms of a number of distinct changes that are numbered consecutively and presented in both a quantitative and qualitative way. Sweden is used as the case and all data regarding energy use apply for Swedish conditions. An exercise like this illustrates the possible outcome of taking sustainability seriously. If sustainability is to be achieved, some images of the future are needed so that potential targets can be identified. This paper does not present forecasts, but illustrates the kind of changes needed in order to achieve sustainable energy use in the food system. (author)

  14. Eating energy-Identifying possibilities for reduced energy use in the future food supply system

    Energy Technology Data Exchange (ETDEWEB)

    Wallgren, Christine [Division of Environmental Strategies Research-fms, Department of Urban Planning and Environment, Royal Institute of Technology, Stockholm (Sweden); Hoejer, Mattias, E-mail: hojer@kth.s [Division of Environmental Strategies Research-fms, Department of Urban Planning and Environment, Royal Institute of Technology, Stockholm (Sweden)

    2009-12-15

    This paper explores the possibilities for reducing future energy use for eating to a sustainable level. A backcasting approach is used to generate an image of the future where energy use for eating is 60% lower in 2050 than in 2000. The currently known potential to reduce energy use in the food supply system for producing, transporting, storing, cooking and eating food is explored and described in terms of a number of distinct changes that are numbered consecutively and presented in both a quantitative and qualitative way. Sweden is used as the case and all data regarding energy use apply for Swedish conditions. An exercise like this illustrates the possible outcome of taking sustainability seriously. If sustainability is to be achieved, some images of the future are needed so that potential targets can be identified. This paper does not present forecasts, but illustrates the kind of changes needed in order to achieve sustainable energy use in the food system.

  15. Assessing the performance of a permeable reactive barrier-aquifer system using a dual-domain solute transport model

    Science.gov (United States)

    Chen, Jui-Sheng; Hsu, Shao-Yiu; Li, Ming-Hsu; Liu, Chen-Wuing

    2016-12-01

    Transport behavior through a permeable reactive barrier (PRB)-aquifer system is complicated because of the different physical and chemical properties of the PRB and the aquifer. Dual-domain solute transport models are efficient tools for better understanding the various processes and mechanisms of reactive solute transport through a PRB-aquifer system. This study develops a dual-domain analytical model to assess the physical and chemical processes of two-dimensional reactive solute transport through a PRB-aquifer system. The dispersion processes of a dual-domain system on the solute transport are investigated. The results show that the dispersion parameters in a dual-domain system synchronously govern the dynamic shape of the contaminant plume. The low longitudinal and transverse dispersion coefficients of a dual-domain system may restrict the spreading of the plume and elevate the plume's concentration level. The derived analytical solution is applied to explore how the different reactive transport processes affect the performance of a PRB-aquifer system. The results show that the first-order decay rate constant of the PRB has a critical effect on the performance of the PRB-aquifer system, whereas the effects of the physical dispersion properties on PRB performance are less significant.

  16. Scatter and crosstalk corrections for {sup 99m}Tc/{sup 123}I dual-radionuclide imaging using a CZT SPECT system with pinhole collimators

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Peng [Department of Diagnostic Radiology, Yale University, New Haven, Connecticut 06520 and Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Hutton, Brian F. [Institute of Nuclear Medicine, University College London, London WC1E 6BT, United Kingdom and Centre for Medical Radiation Physics, University of Wollongong, New South Wales 2522 (Australia); Holstensson, Maria [Department of Nuclear Medicine, Karolinska University Hospital, Stockholm 14186 (Sweden); Ljungberg, Michael [Department of Medical Radiation Physics, Lund University, Lund 222 41 (Sweden); Hendrik Pretorius, P. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Prasad, Rameshwar; Liu, Chi, E-mail: chi.liu@yale.edu [Department of Diagnostic Radiology, Yale University, New Haven, Connecticut 06520 (United States); Ma, Tianyu; Liu, Yaqiang; Wang, Shi [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Thorn, Stephanie L.; Stacy, Mitchel R.; Sinusas, Albert J. [Department of Internal Medicine, Yale Translational Research Imaging Center, Yale University, New Haven, Connecticut 06520 (United States)

    2015-12-15

    Purpose: The energy spectrum for a cadmium zinc telluride (CZT) detector has a low energy tail due to incomplete charge collection and intercrystal scattering. Due to these solid-state detector effects, scatter would be overestimated if the conventional triple-energy window (TEW) method is used for scatter and crosstalk corrections in CZT-based imaging systems. The objective of this work is to develop a scatter and crosstalk correction method for {sup 99m}Tc/{sup 123}I dual-radionuclide imaging for a CZT-based dedicated cardiac SPECT system with pinhole collimators (GE Discovery NM 530c/570c). Methods: A tailing model was developed to account for the low energy tail effects of the CZT detector. The parameters of the model were obtained using {sup 99m}Tc and {sup 123}I point source measurements. A scatter model was defined to characterize the relationship between down-scatter and self-scatter projections. The parameters for this model were obtained from Monte Carlo simulation using SIMIND. The tailing and scatter models were further incorporated into a projection count model, and the primary and self-scatter projections of each radionuclide were determined with a maximum likelihood expectation maximization (MLEM) iterative estimation approach. The extracted scatter and crosstalk projections were then incorporated into MLEM image reconstruction as an additive term in forward projection to obtain scatter- and crosstalk-corrected images. The proposed method was validated using Monte Carlo simulation, line source experiment, anthropomorphic torso phantom studies, and patient studies. The performance of the proposed method was also compared to that obtained with the conventional TEW method. Results: Monte Carlo simulations and line source experiment demonstrated that the TEW method overestimated scatter while their proposed method provided more accurate scatter estimation by considering the low energy tail effect. In the phantom study, improved defect contrasts were

  17. Vortex dynamics in self-dual Chern-Simons Higgs systems

    CERN Document Server

    Kim, Y; Kim, Yoonbai; Lee, Kimyeong

    1994-01-01

    We consider vortex dynamics in self-dual Chern-Simons Higgs systems. We show that the naive Aharanov-Bohm phase is the inverse of the statistical phase expected from the vortex spin, and that the self-dual configurations of vortices are degenerate in energy but not in angular momentum. We also use the path integral formalism to derive the dual formulation of Chern-Simons Higgs systems in which vortices appear as charged particles. We argue that besides the electromagnetic interaction, there is an additional interaction between vortices, the so-called Magnus force, and that these forces can be put together into a single `dual electromagnetic' interaction. This dual electromagnetic interaction leads to the right Aharanov-Bohm phase. We also derive and study the effective action for slowly moving vortices, which contains terms both linear and quadratic in the vortex velocity.

  18. CO2 recovery system using solar energy; Taiyo energy wo riyoshita CO2 bunri kaishu system

    Energy Technology Data Exchange (ETDEWEB)

    Hosho, F.; Naito, H.; Yugami, H.; Arashi, H. [Tohoku University, Sendai (Japan)

    1997-11-25

    As a part of studies on chemical absorption process with MEA (monoethanolamine) for CO2 recovery from boiler waste gas in thermal power plants, use of solar heat as MEA regenerating energy was studied. An integrated stationary evacuated concentrator (ISEC) effective as collector in a medium temperature range was used to realize a regenerating temperature range of 100-120degC. ISEC is featured by vacuum insulation, use of selective absorbing membranes for an absorber, a CPC (compound parabolic concentrator)-shaped reflection mirror, and high-efficiency. An MEA regenerator is composed of an ISEC and PG(propylene glycol)-MEA heat exchanger, and circulates PG as heat medium. Heat collection experiment was also made using water instead of MEA. Both batch and continuous systems could supply a heat quantity necessary for MEA regeneration. CO2 concentration in the top of the regenerator rapidly decreased with PG circulation regenerating MEA. As mol ratios of CO2/MEA were compared between before and after regeneration, a recovery rate was estimated to be 59.4% for the batch system. 8 figs., 4 tabs.

  19. Ubiquitous health monitoring system for multiple users using a ZigBee and WLAN dual-network.

    Science.gov (United States)

    Cha, Yong Dae; Yoon, Gilwon

    2009-11-01

    A ubiquitous health monitoring system for multiple users was developed based on a ZigBee and wireless local area network (WLAN) dual-network. A compact biosignal monitoring unit (BMU) for measuring electrocardiogram (ECG), photoplethysmogram (PPG), and temperature was also developed. A single 8-bit microcontroller operated the BMU including most of digital filtering and wireless communication. The BMU with its case was reduced to 55 x 35 x 15 mm and 33 g. In routine use, vital signs of 6 bytes/sec (heart rate, temperature, pulse transit time) per each user were transmitted through a ZigBee module even though all the real-time data were recorded in a secure digital memory of the BMU. In an emergency or when need arises, a channel of a particular user was switched to another ZigBee module, called the emergency module, that sent all ECG and PPG waveforms in real time. Each emergency ZigBee module handled up to a few users. Data from multiple users were wirelessly received by the ZigBee receiver modules in a controller called ZigBee-WLAN gateway, where the ZigBee modules were connected to a WLAN module. This WLAN module sent all data wirelessly to a monitoring center. Operating the dual modes of ZigBee/WLAN utilized an advantage of ZigBee by handling multiple users with minimum power consumption, and overcame the ZigBee limitation of low data rate. This dual-network system for LAN is economically competitive and reliable.

  20. A dual-frequency fringe projection three-dimensional shape measurement system using a DLP 3D projector

    Science.gov (United States)

    Dai, Meiling; Yang, Fujun; Liu, Cong; He, Xiaoyuan

    2017-01-01

    A dual-frequency fringe projection system for three-dimensional (3D) surface shape measurement is proposed in this paper. The system includes two cameras, a DLP 3D projector, and a liquid crystal (LC) shutter glasses. The phase information related to the object height is obtained from the dual-frequency temporal method with 3-step phase-shifting algorithm. By using the DLP 3D projector and LC shutter glasses, 3-step phase-shifting high-frequency and low-frequency fringe patterns are captured only 3 times by the two cameras synchronously. The technique of image registration is applied to low-frequency fringe patterns to guarantee the accuracy of low-frequency phase for high-frequency phase unwrapping. Using the equi-phase coordinate method based on two reference planes, the phase-to-height conversion and non-sinusoidal errors reduction are carried out in one go without any extra operation or measurement time. Experimental results demonstrate that the proposed method effectively improves the measuring speed, and it is valid for measuring surface shapes with multi-steps or discontinuities.

  1. Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

    Science.gov (United States)

    Wang, Tonghe; Zhu, Lei

    2016-09-01

    Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an

  2. Production Functions for Water Delivery Systems: Analysis and Estimation Using Dual Cost Function and Implicit Price Specifications

    Science.gov (United States)

    Teeples, Ronald; Glyer, David

    1987-05-01

    Both policy and technical analysis of water delivery systems have been based on cost functions that are inconsistent with or are incomplete representations of the neoclassical production functions of economics. We present a full-featured production function model of water delivery which can be estimated from a multiproduct, dual cost function. The model features implicit prices for own-water inputs and is implemented as a jointly estimated system of input share equations and a translog cost function. Likelihood ratio tests are performed showing that a minimally constrained, full-featured production function is a necessary specification of the water delivery operations in our sample. This, plus the model's highly efficient and economically correct parameter estimates, confirms the usefulness of a production function approach to modeling the economic activities of water delivery systems.

  3. Collateral ventilation quantification using xenon-enhanced dynamic dual-energy CT: Differences between canine and swine models of bronchial occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Ah; Goo, Jin Mo; Park, Sang Joon; Lee, Chang Hyun; Park, Chng Min [Dept. of Radiology, Seoul National University College of Medicine and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)

    2015-06-15

    The aim of this study was to evaluate whether the difference in the degree of collateral ventilation between canine and swine models of bronchial obstruction could be detected by using xenon-enhanced dynamic dual-energy CT. Eight mongrel dogs and six pigs underwent dynamic dual-energy scanning of 64-slice dual-source CT at 12-second interval for 2-minute wash-in period (60% xenon) and at 24-second interval for 3-minute wash-out period with segmental bronchus occluded. Ventilation parameters of magnitude (A value), maximal slope, velocity (K value), and time-to-peak (TTP) enhancement were calculated from dynamic xenon maps using exponential function of Kety model. A larger difference in A value between parenchyma was observed in pigs than in dogs (absolute difference, -33.0 +/- 5.0 Hounsfield units [HU] vs. -2.8 +/- 7.1 HU, p = 0.001; normalized percentage difference, -79.8 +/- 1.8% vs. -5.4 +/- 16.4%, p = 0.0007). Mean maximal slopes in both periods in the occluded parenchyma only decreased in pigs (all p < 0.05). K values of both periods were not different (p = 0.892) in dogs. However, a significant (p = 0.027) difference was found in pigs in the wash-in period. TTP was delayed in the occluded parenchyma in pigs (p = 0.013) but not in dogs (p = 0.892). Xenon-ventilation CT allows the quantification of collateral ventilation and detection of differences between canine and swine models of bronchial obstruction.

  4. Single/Dual-Polarized Infrared Rectenna for Solar Energy Harvesting

    Directory of Open Access Journals (Sweden)

    S. H. Zainud-Deen

    2016-05-01

    Full Text Available Single and dual linearly-polarized receiving mode nanoantennas are designed for solar energy harvesting at 28.3 THz. The infrared rectennas are used to harvest the solar energy and converting it to electrical energy.  The proposed infrared rectenna is a thin dipole made of gold and printed on a silicon dioxide substrate. Different shapes of the dipole arms have been investigated for maximum collected energy. The two poles of the dipole have been determined in a rectangular, circular and rhombus shapes. The rectenna dipole is used to concentrate the electromagnetic energy into a small localized area at the inner tips of the gap between the dipole arms. The dimensions of the different dipole shapes are optimized for maximum near electric field intensity at a frequency of 28.3 THz. A Metal Insulator Metal (MIM diode is incorporated with the nanoantenna dipole to rectify the received energy. The receiving efficiency of the solar energy collector with integrated MIM diode has been investigated. A dual-polarized, four arms, rhombus shaped nanoantenna dipole for solar energy harvesting has been designed and optimized for 28.3 THz applications.

  5. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    Energy Technology Data Exchange (ETDEWEB)

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2013-06-15

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of -11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis.

  6. WE-A-BRF-01: Dual-Energy CT Imaging in Diagnostic Imaging and Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Molloi, S [University of California, Irvine, CA (United States); Li, B [Boston University Medical Center, Boston, MA (United States); Yin, F [Duke University Medical Center, Durham, NC (United States); Chen, H [New York Presbyterian Hospital, New York, NY (United States)

    2014-06-15

    The quantification accuracy of dual-energy imaging is influenced by the fundamentals of x-ray physics, system geometry, data acquisition hardware/protocol, system calibration, and image processing technique. This symposium will provide updates on the following advanced application areas: Mammography. Volumetric breast density techniques based on standard mammograms require estimation of breast thickness, which is difficult to accurately measure. By comparison, calculation of breast density using dual energy mammography does not require measurement of breast thickness. Dual energy mammography has been implemented using both energy integrating flat panel detectors in conjunction with beam energy switching and energy resolved photon counting detectors. These techniques have been optimized using simulation studies and validated using physical phantoms and postmortem breasts. Chemical decomposition was used as the gold standard for volumetric breast density measurement in postmortem breasts. Breast density measurements have also been compared with results from four-category BI-RADS density rankings, standard image thresholding and Fuzzy k-mean clustering techniques. These studies indicate that dual energy mammography can be used to accurately measure volumetric breast density. Cardiovascular CT. The predicative accuracy of risk models for recurrent stroke and cardiac arrest depends heavily on accurate differentiation of thrombus or calcium from iodine in left atrial appendage or coronary arteries. The amount of energy separation is constrained by image noise; therefore, optimal kVp, beam filtration, and balanced flux are essential for the quantification accuracy of iodine and calcium. The basis materials are combined linearly to generate monochromatic energy images, where CT# accuracy and CNR are energy dependent. With optimal monochromatic energy, the mean iodine concentration for the thrombus, circulatory stasis, and control groups are significantly different. Risk

  7. Dual Energy Method for Breast Imaging: A Simulation Study

    Directory of Open Access Journals (Sweden)

    V. Koukou

    2015-01-01

    Full Text Available Dual energy methods can suppress the contrast between adipose and glandular tissues in the breast and therefore enhance the visibility of calcifications. In this study, a dual energy method based on analytical modeling was developed for the detection of minimum microcalcification thickness. To this aim, a modified radiographic X-ray unit was considered, in order to overcome the limited kVp range of mammographic units used in previous DE studies, combined with a high resolution CMOS sensor (pixel size of 22.5 μm for improved resolution. Various filter materials were examined based on their K-absorption edge. Hydroxyapatite (HAp was used to simulate microcalcifications. The contrast to noise ratio (CNRtc of the subtracted images was calculated for both monoenergetic and polyenergetic X-ray beams. The optimum monoenergetic pair was 23/58 keV for the low and high energy, respectively, resulting in a minimum detectable microcalcification thickness of 100 μm. In the polyenergetic X-ray study, the optimal spectral combination was 40/70 kVp filtered with 100 μm cadmium and 1000 μm copper, respectively. In this case, the minimum detectable microcalcification thickness was 150 μm. The proposed dual energy method provides improved microcalcification detectability in breast imaging with mean glandular dose values within acceptable levels.

  8. Reduced energy consumption by using streamlined gating systems

    Institute of Scientific and Technical Information of China (English)

    Seren Skov-Hansen; Niels Skat Tiedje

    2008-01-01

    In foundries a lot of effort is done to minimize energy consumption in the production to reduce costs and hence increase the competitiveness. At the same time the foundries must live up to the increased demands for high quality castings.Traditional gating systems are known for a straight tapered down runner, a well base and 90° bends in the runner system. Previous work has shown that the traditional way of designing gating systems creates high inconsistency in flow patterns during filling. In the streamlined gating systems there are no sharp changes in direction and a large effort is done to confine and control the flow of the molten metal during mould filling. The main objective in the work presented here is to use the principles of the streamlined gating systems to reduce the weight of the gating system relative to the traditional layouts. By reducing the weight of gating system and thereby improving yield, the amount of molten iron needed is also reduced, hence reducing the energy consumption for melting.Experiments in real production lines have proven that it is possible to achieve a reduction in the poured weight by using the streamlined gating systems. In a layout for casting of three valve housings in a vertically parted mould the weight of the gating system was reduced by 1.1 kg changing from the traditional layouts to the streamlined gating systems. This weight reduction corresponds in this case to a 20% weight reduction for the gating system. Using streamlined gating systems with fan gates to give a beneficial heat distribution in the castings may be an efficient tool to eliminate the need for heat treatment. In the experiments the change in gating system from the traditional layout to the streamlined layout removed the need for heat treatment. This obviously means a huge energy saving in the foundry. The energy consumption for heat treatment of iron has been found to be 0.489 kWh/kg. The valve housing in the experiments weighs 3 kg so when the need for

  9. Risoe energy report 4: The future energy system - distributed production and use

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Hans; Soenderberg Petersen, L.

    2005-10-01

    The world is facing major challenges in providing energy services to meet the future needs of the developed world and the growing needs of developing countries. These challenges are exacerbated by the need to provide energy services with due respect to economic growth, sustainability and security of supply. Today, the world's energy system is based mainly on oil, gas and coal, which together supply around 80% of our primary energy. Only around 0.5% of primary energy comes from renewable sources such as wind, solar and geothermal. Despite the rapid development of new energy technologies, the world will continue to depend on fossil fuels for several decades to come - and global primary energy demand is forecasted to grow by 60% between 2002 and 2030. The expected post Kyoto targets call for significant CO{sub 2} reductions, increasing the demand to decouple the energy and transport systems from fossil fuels. There is a strong need for closer links between electricity, heat and other energy carriers, including links to the transport sector. On a national scale Denmark has three main characteristics. Firstly, it has a diverse and distributed energy system based on the power grid, the district heating grid and the natural gas grid. Secondly, renewable energy, especially wind power, plays an increasingly important role in the Danish energy system. Thirdly, Denmark's geographical location allows it to act as a buffer between the energy systems of the European continent and the Nordic countries. Energy systems can be made more robust by decentralising both power generation and control. Distributed generation (DG) is characterised by a variety of energy production technologies integrated into the electricity supply system, and the ability of different segments of the grid to operate autonomously. The use of a more distributed power generation system would be an important element in the protection of the consumers against power interruptions and blackouts, whether

  10. 双轴伺服太阳能跟踪系统的设计%Design of the Dual-axis Servo Solar Energy Tracking System

    Institute of Scientific and Technical Information of China (English)

    汤世松; 舒志兵

    2011-01-01

    In order to fully utilize solar energy with high efficiency, the dual-axis servo solar tracking system based on PLC has been designed.By adopting sun motion trajectory tracking strategy, the position of the sun in daytime is calctdated by controller in accordance with related formula and parameters, then the altitude and azimuth are converted into corresponding pulses to be sended to servo driver; and the servo motor tracks the sun in real time.Therefore, the solar energy panel is always tilting towards the sun when the system tracks the sun from east to west,thus maximum solar energy is obtained.The theoretical analysis indicates that by adopting this tracking technology, the efficiency of receiving solar energy can be increased.%为了更充分、高效地利用太阳能,设计了基于PLC的双轴伺服太阳能跟踪系统.该系统采用视日运动轨迹跟踪方案,控制器根据相关的公式和参数计算出白天太阳的位置,再将高度角和方位角转化成相应的脉冲发送给伺服驱动器,驱动伺服电机实时跟踪太阳.同时,系统使太阳能板随着太阳的高度变化而倾斜,从而获得最大的太阳能.理论分析表明,采用该跟踪技术可以有效地提高能量接收率.

  11. Decreased stage migration rate of early gastric cancer with a new reconstruction algorithm using dual-energy CT images: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Cen [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Ruijin Hospital, Shanghai (China); First Affiliated Hospital of Soochow University, Department of Radiology, Suzhou (China); Zhang, Huan; Du, Lianjun; Pan, Zilai; Yan, Fuhua [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Ruijin Hospital, Shanghai (China); Yan, Jing [Siemens Medical System, Shanghai (China); Wang, Baisong [Shanghai Jiao Tong University School of Medicine, Department of Biological Statistics, Shanghai (China)

    2017-02-15

    To evaluate the potential value of advanced monoenergetic images (AMEIs) on early gastric cancer (EGC) using dual-energy CT (DECT). 31 EGC patients (19 men, 12 women; age range, 38-81 years; mean age, 57.19 years) were retrospectively enrolled in this study. Conventionally reconstructed polyenergetic images (PEIs) at 120 kV and virtual monoenergetic images (MEIs) and AMEIs at six different kiloelectron volt (keV) levels (from 40 to 90 keV) were evaluated from the 100 and Sn 140 kV dual energy image data, respectively. The visibility and stage migration of EGC for all three image data sets were evaluated and statistically analyzed. The objective and subjective image qualities were also evaluated. AMEIs at 40 keV showed the best visibility (80.7 %) and the lowest stage migration (35.5 %) for EGC. The stage migration for AMEIs at 40 keV was significantly lower than that for PEIs (p = 0.026). AMEIs at 40 keV had statistically higher CNR in the arterial and portal phases, gastric-specific diagnostic performance and visual sharpness compared with other AMEIs, MEIs and PEIs (all p < 0.05). AMEIs at 40 keV with MPR increase the CNR of EGC and thus potentially lower the stage migration of EGC. (orig.)

  12. Dual-energy CT angiography of the lung in patients with suspected pulmonary embolism. Initial results

    Energy Technology Data Exchange (ETDEWEB)

    Fink, C.; Michaely, H.J. [Inst. fuer Klinische Radiologie und Nuklearmedizin, Universitaetsklinikum Mannheim, Univ. Heidelberg (Germany); Inst. fuer Klinische Radiologie, Campus Grosshadern, Klinikum der Univ. Muenchen (Germany); Johnson, T.R.; Morhard, D.; Becker, C.; Reiser, M.; Nikolaou, K. [Inst. fuer Klinische Radiologie, Campus Grosshadern, Klinikum der Univ. Muenchen (Germany)

    2008-10-15

    To evaluate the feasibility of dual-energy CT angiography (CTA) of the lung in patients with suspected pulmonary embolism (PE). 24 patients with suspected PE were examined with a single-acquisition, dual-energy CTA protocol (A-system: 140 kV/65 mAsref, B-system: 80 kV/190 mAsref) on a dual-source CT system. Lung perfusion was visualized by color-coding voxels containing iodine and air using dedicated dual-energy post-processing software. Perfusion defects were classified by two blinded radiologists as being consistent or non-consistent with PE. Subjective image quality of perfusion maps and CTA was rated using a 5-point scale (1: excellent, 5: poor). The reading of a third independent radiologist served as the standard of reference for the diagnosis of PE. In all patients with PE (n = 4), perfusion defects classified as being consistent with PE were identified in lung areas affected by PE. Both readers did not record perfusion defects classified as being consistent with PE in any of the patients without PE. Thus, on a per patient basis the sensitivity and specificity for the assessment of PE was 100% for both readers. On a per segment basis the sensitivity and specificity ranged between 60 - 66.7% and 99.5 - 99.8%. The interobserver agreement was good (k = 0.81). Perfusion defects rated as non-consistent with PE were most frequently caused by streak artifacts from dense contrast material in the great thoracic vessels. The median score of the image quality of both the perfusion maps and CTA was 2. In conclusion, dual-energy CTA of pulmonary embolism is feasible and allows the assessment of perfusion defects caused by pulmonary embolism. Further optimization of the injection protocol is required to reduce artifacts from dense contrast material. (orig.)

  13. Tuning controllers using the dual Youla parameterization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2000-01-01

    This paper describes the application of the Youla parameterization of all stabilizing controllers and the dual Youla parameterization of all systems stabilized by a given controller in connection with tuning of controllers. In the uncertain case, it is shown that the use of the Youla...

  14. Rapid determination of dopamine in human plasma using a gold nanoparticle-based dual-mode sensing system.

    Science.gov (United States)

    Zhang, Yali; Qi, Suijian; Liu, Zhonggang; Shi, Yupeng; Yue, Wanqing; Yi, Changqing

    2016-04-01

    Dopamine plays a very important role in biological systems and has a direct relationship with the ability of learning and cognition, human desires, feelings and mental state, as well as motor functions. Traditional methods for the detection of dopamine are complicated and time-consuming, therefore it is necessary to explore rapid and accurate detection of dopamine with high sensitivity and specificity. Herein we report a dual-mode system of colorimetric and fluorometric analyses based on gold nanoparticles (AuNPs) and aptamers specifically targeting dopamine. Aptamers modified with the fluorophore were used as dopamine specific recognition probe and the sensing mechanism is based on the color change of AuNPs and the fluorescence recovery of fluorophore conjugated on the aptamers in the presence of dopamine. The addition of aptamers into AuNPs colloid solution would prevent the AuNPs from aggregation in the high-salt solution. The close distance between AuNPs and fluorophore conjugated on the aptamers would lead to the quenching of fluorescence signal. In the presence of dopamine, the conformation of the aptamers and the inter-particle distance would be changed, leading to the aggregation of AuNPs, which subsequently results in color change from red to blue and fluorescence signal recovery. The dual-mode sensing system demonstrated high specificity towards dopamine with the detection limit as low as 78.7 nM. The sensing system reflects on its simplicity as no surface functionalization is required for the nanoparticles, leading to less laborious and more cost-effective synthesis. The reaction time is only 6 min, demonstrating a simple approach for rapid analysis of dopamine. More importantly, the sensing system allows the detection of dopamine in both aqueous solution and complicated biological sample with sensitive response, illustrating the feasibility and reliability for the potential applications in clinical and biomedical analysis in the future.

  15. Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Mark [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Norwich Radiology Academy, Norwich (United Kingdom); Reid, Karen [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Toms, Andoni P. [Norfolk and Norwich University Hospital and University of East Anglia, Norwich (United Kingdom)

    2013-02-15

    The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons. Two phantoms were used: a Charnley total hip replacement set in gelatine and a Catphan 500. DECT datasets were acquired at 100, 200 and 400 mA (Siemens Definition Flash, 100 and 140 kVp) and reconstructed using a standard combined algorithm (1:1) and then as monoenergetic reconstructions at 10 keV intervals from 40 to 190 keV. Semi-automated segmentation with threshold inpainting was used to obtain the attenuation values and standard deviation (SD) of the streak artefact. High contrast line pair resolution and background noise were assessed using the Catphan 500. Streak artefact is progressively reduced with increasing keV monoenergetic reconstructions. Reconstruction of a 400 mA acquisition at 150 keV results in reduction in the volume of streak artefact from 65 cm{sup 3} to 17 cm{sup 3} (74 %). There was a decrease in the contrast to noise ratio (CNR) at higher tube voltages, with the peak CNR seen at 70-80 keV. High contrast spatial resolution was maintained at high keV values. Monoenergetic reconstruction of dual energy CT at increasing theoretical kilovoltages reduces the streak artefact produced by beam hardening from orthopaedic prostheses, accompanied by a modest increase in heterogeneity of background image attenuation, and decrease in contrast to noise ratio, but no deterioration in high contrast line pair resolution. (orig.)

  16. Polymerization kinetics of dual-curing adhesive systems when used solely or in conjunction with chemically-cured resin cement.

    Science.gov (United States)

    Kim, Young Kyung; Chun, Ju-Na; Kwon, Pyung Cheol; Kim, Kyo-Han; Kwon, Tae-Yub

    2013-10-01

    To investigate the chemical polymerization kinetics of commercial dual-curing adhesive systems when used solely or in conjunction with chemically-curing resin cement. Four adhesive systems comprising simplified-step adhesives and activators (Prime&Bond NT with Self Cure Activator, Excite DSC, AQ Bond Plus, All-Bond SE) were used. The pH values of the adhesives and adhesive/activator blends were measured. Differential scanning calorimetry (DSC) was used to investigate the extent of the chemical polymerization of the adhesives when used alone or directly intermixed with a chemically-cured resin cement (C&B Cement) for 60 min (n = 5). The data derived from the DSC analysis were statistically compared using one-way ANOVA and the Games-Howell post-hoc test (α = 0.05). All the adhesives were highly acidic; when they were blended with the respective activators, their pH values increased. Neither the adhesive/activator blends nor the adhesive alone/cement mixtures showed any detectable heat generation. The Prime&Bond NT/activator showed delayed heat generation only when intermixed with the catalyst/base paste. The other three adhesive systems produced similar exotherms when intermixed with the catalyst paste alone or with the catalyst/base paste (p > 0.05), but at significantly different maximum rates of polymerization (p adhesive system/resin cement interface appears highly dependent on the adhesive system used and may be considerably delayed.

  17. Severity assessment of pulmonary embolism using dual energy CT - correlation of a pulmonary perfusion defect score with clinical and morphological parameters of blood oxygenation and right ventricular failure

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, Sven F. [Ludwig-Maximilians-Universitaet, Department of Clinical Radiology, Muenchen (Germany); Institut fuer Klinische Radiologie der LMU Muenchen, Muenchen (Germany); Ashoori, Nima; Bamberg, Fabian; Sommer, Wieland H.; Johnson, Thorsten R.C.; Maxien, Daniel; Helck, Andreas D.; Reiser, Maximilian F.; Nikolaou, Konstantin [Ludwig-Maximilians-Universitaet, Department of Clinical Radiology, Muenchen (Germany); Leuchte, Hanno; Becker, Alexander [Ludwig-Maximilians-Universitaet, Department of Medicine I, Muenchen (Germany); Behr, Juergen [Ludwig-Maximilians-Universitaet, Department of Medicine I, Muenchen (Germany); Berufsgenossenschaftliches Universitaetsklinikum Bergmannsheil GmbH Ruhr-Universitaet Bochum, Department of Medicine III, Bochum (Germany)

    2012-02-15

    To correlate a Dual Energy (DE)-based visual perfusion defect scoring system with established CT-based and clinical parameters of pulmonary embolism (PE) severity. In 63 PE patients, DE perfusion maps were visually scored for perfusion defects (P-score). Vascular obstruction was quantified using the Mastora score. Both scores were correlated with short-axis diameters of the right and left ventricle, their ratio (RV/LV ratio), width of the pulmonary trunk, a number of clinical parameters and each other. Univariate and multivariate analyses were performed. Times to generate both scores were recorded. After univariate and multivariate analysis, a significant (p < 0.05) correlation with the P-score was shown for the Mastora score (r = 0.65), RV/LV ratio (r = 0.47), width of the pulmonary trunk (r = 0.26), troponin I (r = 0.43) and PaO{sub 2} (r = -0.50). For the left ventricular diameter, only univariate analysis showed a significant correlation. Mastora score correlated significantly with RV/LV ratio (r = 0.36), width of the pulmonary trunk (r = 0.27), PaO{sub 2} (r = -0.41) and troponin I (r = 0.37). Mean time for generating the P-score was significantly shorter than for the Mastora score. A DE-based P-score correlates with a number of parameters of PE severity. It might be easier and faster to perform than some traditional CT scoring methods for vascular obstruction. (orig.)

  18. Severity assessment of pulmonary embolism using dual energy CT - correlation of a pulmonary perfusion defect score with clinical and morphological parameters of blood oxygenation and right ventricular failure.

    Science.gov (United States)

    Thieme, Sven F; Ashoori, Nima; Bamberg, Fabian; Sommer, Wieland H; Johnson, Thorsten R C; Leuchte, Hanno; Becker, Alexander; Maxien, Daniel; Helck, Andreas D; Behr, Jürgen; Reiser, Maximilian F; Nikolaou, Konstantin

    2012-02-01

    To correlate a Dual Energy (DE)-based visual perfusion defect scoring system with established CT-based and clinical parameters of pulmonary embolism (PE) severity. In 63 PE patients, DE perfusion maps were visually scored for perfusion defects (P-score). Vascular obstruction was quantified using the Mastora score. Both scores were correlated with short-axis diameters of the right and left ventricle, their ratio (RV/LV ratio), width of the pulmonary trunk, a number of clinical parameters and each other. Univariate and multivariate analyses were performed. Times to generate both scores were recorded. After univariate and multivariate analysis, a significant (p < 0.05) correlation with the P-score was shown for the Mastora score (r = 0.65), RV/LV ratio (r = 0.47), width of the pulmonary trunk (r = 0.26), troponin I (r = 0.43) and PaO(2) (r = -0.50). For the left ventricular diameter, only univariate analysis showed a significant correlation. Mastora score correlated significantly with RV/LV ratio (r = 0.36), width of the pulmonary trunk (r = 0.27), PaO(2) (r = -0.41) and troponin I (r = 0.37). Mean time for generating the P-score was significantly shorter than for the Mastora score. A DE-based P-score correlates with a number of parameters of PE severity. It might be easier and faster to perform than some traditional CT scoring methods for vascular obstruction.

  19. Study on absorption coefficients of dual-energy γ-rays in determining phase fractions of multiphase flows

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-biao; LI Dong-hui; WU Ying-xiang

    2005-01-01

    This paper discusses the principle and mathematical method to measure the phase fractions of multiphase flows by using a dual-energy gamma-ray system. The dual-energy gamma-ray device is composed of radioactive isotopes of 241Am and 137Cs with emission energies of 59.5 keV and 662 keV respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The statistical error has been analyzed on the basis of the accurate absorption coefficient which enables determination phrase fractions almost independent of the flow regime. Improvement has been achieved on the measurement accuracy of phase fractions.

  20. Diagnosis of pulmonary artery embolism. Comparison of single-source CT and 3{sup rd} generation dual-source CT using a dual-energy protocol regarding image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Petritsch, Bernhard; Kosmala, Aleksander; Gassenmeier, Tobias; Weng, Andreas Max; Veldhoen, Simon; Kunz, Andreas Steven; Bley, Thorsten Alexander [Univ. Hospital Wuerzburg (Germany). Inst. of Diagnostic and Interventional Radiology

    2017-06-15

    To compare radiation dose, subjective and objective image quality of 3 rd generation dual-source CT (DSCT) and dual-energy CT (DECT) with conventional 64-slice single-source CT (SSCT) for pulmonary CTA. 180 pulmonary CTA studies were performed in three patient cohorts of 60 patients each. Group 1: conventional SSCT 120 kV (ref.); group 2: single-energy DSCT 100 kV (ref.); group 3: DECT 90/Sn150 kV. CTDIvol, DLP, effective radiation dose were reported, and CT attenuation (HU) was measured on three central and peripheral levels. The signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. Two readers assessed subjective image quality according to a five-point scale. Mean CTDIvol and DLP were significantly lower in the dual-energy group compared to the SSCT group (p < 0.001 [CTDIvol]; p < 0.001 [DLP]) and the DSCT group (p = 0.003 [CTDIvol]; p = 0.003 [DLP]), respectively. The effective dose in the DECT group was 2.79 ± 0.95 mSv and significantly smaller than in the SSCT group (4.60 ± 1.68 mSv, p < 0.001) and the DSCT group (4.24 ± 2.69 mSv, p = 0.003). The SNR and CNR were significantly higher in the DSCT group (p < 0.001). Subjective image quality did not differ significantly among the three protocols and was rated good to excellent in 75 % (135/180) of cases with an inter-observer agreement of 80 %. Dual-energy pulmonary CTA protocols of 3 rd generation dual-source scanners allow for significant reduction of radiation dose while providing excellent image quality and potential additional information by means of perfusion maps. Dual-energy CT with 90/Sn150 kV configuration allows for significant dose reduction in pulmonary CTA. Subjective image quality was similar among the three evaluated CT-protocols (64-slice SSCT, single-energy DSCT, 90/Sn150 kV DECT) and was rated good to excellent in 75% of cases. Dual-energy CT provides potential additional information by means of iodine distribution maps.

  1. Identify Web-page Content meaning using Knowledge based System for Dual Meaning Words

    OpenAIRE

    Sinha, Sukanta; Dattagupta, Rana; Mukhopadhyay, Debajyoti

    2012-01-01

    Meaning of Web-page content plays a big role while produced a search result from a search engine. Most of the cases Web-page meaning stored in title or meta-tag area but those meanings do not always match with Web-page content. To overcome this situation we need to go through the Web-page content to identify the Web-page meaning. In such cases, where Webpage content holds dual meaning words that time it is really difficult to identify the meaning of the Web-page. In this paper, we are introdu...

  2. Cascaded-Systems Analysis of Flat-Panel Sandwich Detectors for Single-Shot Dual-Energy X-ray Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Kyung; Kim, Dong Woon; Kim, Junwoo; Youn, Hanbean [Pusan National University, Busan (Korea, Republic of)

    2015-05-15

    We have developed the cascaded-systems model to investigate the signal and noise characteristics in the flat-panel sandwich detector which was developed for the preclinical single-shot dual-energy x-ray imaging. The model incorporates parallel branches to include direct interaction of x-rays in photodiode that is unavoidable in the sandwich structure with a corresponding potential increase in image noise. The model has been validated in comparison with the experimental. The cascaded-systems analysis shows that direct x-ray interaction noise behaves as additive electronic noise that is white in the frequency domain; hence it is harmful to the DQE at higher frequencies where the number of secondary quanta lessens. Even at zero frequency, the direct x-ray interaction noise can reduce the DQE of the detectors investigated in this study by ∼20% for the 60 kV x-ray spectrum. The DQE of rear detector in the sandwich structure is sensitive to additive electronic noise because of the enhancement in the number of electronic noise quanta relative to that of x-ray quanta that are attenuated through the front layers including the intermediate filter layer (i.e. incident photon fluence times transmission factor)

  3. Studies on absorption coefficients of dual-energy γ-rays and measuring error correction for multiphase fraction determination

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article, principle and mathematical method of determining the phase fractions of multiphase flows by using a dual-energy γ-ray system have been described. The dual-energy γ-ray device is composed of radioactive isotopes of 241Am and 137Cs with γ-ray energies of 59.5 and 662 keV, respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The modified arithmetic is beneficial to removing the extra Compton scattering from the measured value. The result shows that the dual-energy γ-ray technique can be used in three-phase flow with average accuracy greater than 95%, which enables us to determine phase fractions almost independent of the flow regime. Improvement has been achieved on measurement accuracy of phase fractions.

  4. Long-term affected energy production of waste to energy technologies identified by use of energy system analysis

    DEFF Research Database (Denmark)

    Münster, Marie; Meibom, Peter

    2010-01-01

    production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments...... and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO2 quota costs are analysed. It is demonstrated that the waste...... incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste...

  5. Dual System for Enhancing Cognitive Abilities of Children with ADHD Using Leap Motion and eye-Tracking Technologies.

    Science.gov (United States)

    Garcia-Zapirain, Begoña; de la Torre Díez, Isabel; López-Coronado, Miguel

    2017-07-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a brain disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that affects with development or functioning. It affects 3-5% of all American and European children. The objective of this paper is to develop and test a dual system for the rehabilitation of cognitive functions in children with ADHD. A technological platform has been developed using the ". NET framework", which makes use of two physiological sensors, -an eye-tracker and a hand gesture recognition sensor- in order to provide children with the opportunity to develop their learning and attention skills. The two physiological sensors we utilized for the development are the Tobii X1 Light Eye Tracker and the Leap Motion. SUS and QUIS questionnaires have been carried out. 19 users tested the system and the average age was 10.88 years (SD = 3.14). The results obtained after tests were performed were quite positive and hopeful. The learning of the users caused by the system and the interfaces item got a high punctuation with a mean of 7.34 (SD = 1.06) for SUS questionnaire and 7.73 (SD = 0.6) for QUIS questionnaire. We didn't find differences between boys and girls. The developed multimodal rehabilitation system can help to children with attention deficit and learning issues. Moreover, the teachers may utilize this system to track the progression of their students and see their behavior.

  6. Personnel Security System using Bluetooth Low Energy (BLE Tag

    Directory of Open Access Journals (Sweden)

    K.Gautham

    2013-04-01

    Full Text Available One of the primary aspects of Personal security is through various user authentication techniques like biometrics, password, Smart Card, etc. We propose to design a personal security authentication system using the commonly available Bluetooth technology. The authentication is done on a fixed device, connected to the web and the identity is provided by a mobile device commonly carried by the person. Almost every cell phone has Bluetooth® transceiver for connecting to a wireless headset or to a host PC. Many new cars have Bluetooth to let you talk hands free while driving. Bluetooth has thus emerged as a pervasive technology. The aim of the paper is to describe a Personnel Security System using Bluetooth Low Energy (BLE Tag which operates on a coin cell battery that will discover all the available low energy devices in the vicinity and keep track of when it entered and when it left the zone. In addition, this tag can also be used as a positioning device by measuring the Received Signal Strength (RSSI value. The initial phase is aimed at designing the hardware for the tag. The second phase is initiated towards programming the tag. The final phase is targeted towards testing the designed hardware module and developing a Personnel Security System.

  7. Search for novel contrast materials in dual-energy x-ray breast imaging using theoretical modeling of contrast-to-noise ratio.

    Science.gov (United States)

    Karunamuni, R; Maidment, A D A

    2014-08-01

    Contrast-enhanced (CE) dual-energy (DE) x-ray breast imaging uses a low- and high-energy x-ray spectral pair to eliminate soft-tissue signal variation and thereby increase the detectability of exogenous imaging agents. Currently, CEDE breast imaging is performed with iodinated contrast agents. These compounds are limited by several deficiencies, including rapid clearance and poor tumor targeting ability. The purpose of this work is to identify novel contrast materials whose contrast-to-noise ratio (CNR) is comparable or superior to that of iodine in the mammographic energy range. A monoenergetic DE subtraction framework was developed to calculate the DE signal intensity resulting from the logarithmic subtraction of the low- and high-energy signal intensities. A weighting factor is calculated to remove the dependence of the DE signal on the glandularity of the breast tissue. Using the DE signal intensity and weighting factor, the CNR for materials with atomic numbers (Z) ranging from 1 to 79 are computed for energy pairs between 10 and 50 keV. A group of materials with atomic numbers ranging from 42 to 63 were identified to exhibit the highest levels of CNR in the mammographic energy range. Several of these materials have been formulated as nanoparticles for various applications but none, apart from iodine, have been investigated as CEDE breast imaging agents. Within this group of materials, the necessary dose fraction to the LE image decreases as the atomic number increases. By reducing the dose to the LE image, the DE subtraction technique will not provide an anatomical image of sufficient quality to accompany the contrast information. Therefore, materials with Z from 42 to 52 provide nearly optimal values of CNR with energy pairs and dose fractions that provide good anatomical images. This work is intended to inspire further research into new materials for optimized CEDE breast functional imaging.

  8. Thermoeconomic Lifecycle Energy Recovery System Optimization for Central Air-Conditioning System Using Evolutionary Technique

    Directory of Open Access Journals (Sweden)

    Liaquat Ali Khan

    2012-01-01

    Full Text Available Energy efficient systems are the most desirable systems. Due to huge rise in energy prices and lack of availability of energy, the effective use of energy has become the need of time. Energy recovery both in heating systems as well as in air-conditioning systems saves a lot of energy. In this paper energy recovery system has been designed and optimized for central air-conditioning systems for various ranges. Cost function includes capital cost along with pumping and exergy destruction cost. This shows that installation of energy recovery system with a central air-conditioning has a significant amount of saved energy and payback period is within a year. PFHE (Plate Fin Heat Exchanger is designed and optimized using evolutionary optimization. In order to verify the capabilities of the proposed method, a case study is also presented showing that significant amount of energy is recovered at a reasonable payback period. Sensitivity analysis is also done with the energy prices.

  9. Quantification of breast density with dual energy mammography: An experimental feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2010-02-15

    Purpose: Breast density, the percentage of glandular breast tissue, has been shown to be a strong indicator of breast cancer risk. A quantitative method to measure breast density with dual energy mammography was investigated using physical phantoms. Methods: The dual energy mammography system used a tungsten anode x-ray tube with a 50 {mu}m rhodium beam filter for low energy images and a 300 {mu}m copper beam filter for high energy images. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Four different phantom studies were used to evaluate the technique. The first study consisted of phantoms with thicknesses of 2.5-8.5 cm in 0.5 cm steps with variable densities centered at a mean of 28%. The second study consisted of phantoms at a fixed thickness of 4.0 cm, which ranged in densities from 0% to 100% in increments of 12.5%. The third study consisted of 4.0 cm thick phantoms at densities of 25%, 50% and 75% each imaged at three areal sizes, approximately 62.5, 125, and 250 cm{sup 2}, in order to assess the effect of breast size on density measurement. The fourth study consisted of step phantoms designed to more closely mimic the shape of a female breast with maximal thicknesses from 3.0 to 7.0 cm at a fixed density of 50%. All images were corrected for x-ray scatter. Results: The RMS errors in breast density measurements were 0.44% for the variable thickness phantoms, 0.64% for the variable density phantoms, 2.87% for the phantoms of different areal sizes, and 4.63% for step phantoms designed to closely resemble the shape of a breast. Conclusions: The results of the phantom studies indicate that dual energy mammography can be used to measure breast density with an RMS error of approximately 5%.

  10. Appropriate patient selection at abdominal dual-energy CT using 80 kV: relationship between patient size, image noise, and image quality.

    Science.gov (United States)

    Guimarães, Luís S; Fletcher, Joel G; Harmsen, William S; Yu, Lifeng; Siddiki, Hassan; Melton, Zachary; Huprich, James E; Hough, David; Hartman, Robert; McCollough, Cynthia H

    2010-12-01

    To determine the computed tomographic (CT) detector configuration, patient size, and image noise limitations that will result in acceptable image quality of 80-kV images obtained at abdominal dual-energy CT. The Institutional Review Board approved this HIPAA-compliant retrospective study from archival material from patients consenting to the use of medical records for research purposes. A retrospective review of contrast material-enhanced abdominal dual-energy CT scans in 116 consecutive patients was performed. Three gastrointestinal radiologists noted detector configuration and graded image quality and artifacts at specified levels-midliver, midpancreas, midkidneys, and terminal ileum-by using two five-point scales. In addition, an organ-specific enhancement-to-noise ratio and background noise were measured in each patient. Patient size was measured by using the longest linear dimension at the level of interest, weight, lean body weight, body mass index, and body surface area. Detector configuration, patient sizes, and image noise levels that resulted in unacceptable image quality and artifact rankings (score of 4 or higher) were determined by using multivariate logistic regression. A 14 × 1.2-mm detector configuration resulted in fewer images with unacceptable quality than did the 64 × 0.6-mm configuration at all anatomic levels (P = .004, .01, and .02 for liver, pancreas, and kidneys, respectively). Image acceptability for the kidneys and ileum was significantly greater than that for the liver for all readers and detector configurations (P < .001). For the 14 × 1.2-mm detector configuration, patient longest linear dimensions yielding acceptable image quality across readers ranged from 34.9 to 35.8 cm at the four anatomic levels. An 80-kV abdominal CT can be performed with appropriate diagnostic quality in a substantial percentage of the population, but it is not recommended beyond the described patient size for each anatomic level. The 14 × 1.2-mm detector

  11. ASSESSMENT OF ENERGY SAVING IN WASTE RECYCLING USING SYSTEM DYNAMICS

    Directory of Open Access Journals (Sweden)

    Eugênio de Oliveira Simonetto

    2013-06-01

    Full Text Available Recycling is a topic of great importance in integrated waste management, evidence of this is verified in the National Policy of Solid Waste, decreed in 2010, where it is considered one of the priorities. In this article is presented a computer simulation model, since their development until its validation, which aims to support environmental managers in their decisions regarding the definition and / or maintenance of solid waste policies recycling, as well as evaluating the benefits of process in the environment (in this article we evaluated the energy savings. For the model development was considered: the rate of natural population growth (births and deaths, percentage of solid waste recycled (for each type of material, gravimetric composition of the material in the total waste generated, the amount of waste generated per inhabitant and energy savings caused by each distinct type of material. Through the model results generated, end users (environmental managers thereof may, for example, set incentives to reduce the total generation of solid waste, produce campaigns enhancing reuse and recycling and to assess the relative benefits of energy savings caused by recycling. Model validation was through analysis of future scenarios for a given municipality in southern Brazil. For modeling and system validation was used Vensim from Ventana Systems.

  12. Risø energy report 4. The future energy system - distributed production and use

    DEFF Research Database (Denmark)

    Larsen, Hans Hvidtfeldt; Sønderberg Petersen, Leif

    2005-01-01

    The coming decades will bring big changes in energy systems throughout the world. The systems are expected to change from central power plants producing electricity and maybe heat for the customers to a combination of central units and a variety ofdistributed units such as renewable energy...... technologies or fuel cells. Furthermore the following developments are expected: -closer link between supply and end-use -closer link between the various energy carriers distributed through grids such aselectricity, heat, natural gas and maybe hydrogen in the future -increased energy trade across national...... by an international panel of independent experts. Information on current developments is taken from the most up-to-date and authoritative sources available. Our target groups are colleagues, collaborating partners, customers, fundingorganisations, the Danish government and international organisations including...

  13. Home Energy Management System Using NILM, Low-Cost HAN

    Institute of Scientific and Technical Information of China (English)

    Qasim Khalid; Naveed Arshad; Nasir Khan; Taha Hassan; Fahad Javed; Jahangir Ikram

    2014-01-01

    Home energy management systems (HEMs) are used to provide comfortable life for consumers as well as to save energy. An essential component of HEMs is a home area network (HAN) that is used to remotely control the electric devices at homes and buildings. Although HAN prices have dropped in recent years but they are still expensive enough to prohibit a mass scale deployments. In this paper, a very low cost alternative to the expensive HANs is presented. We have applied a combination of non-intrusive load monitoring (NILM) and very low cost one-way HAN to develop a HEM. By using NILM and machine learning algorithms we find the status of devices and their energy consumption from a central meter and communicate with devices through the one-way HAN. The evaluations show that the proposed machine learning algorithm for NILM achieves up to 99%accuracy in certain cases. On the other hand our radio frequency (RF)-based one-way HAN achieves a range of 80 feet in all settings.

  14. Land-use implications of wind-energy-conversion systems

    Science.gov (United States)

    Noun, R. J.

    1981-02-01

    An estimated 20 utilities in the United States are now investigating potential wind machine sites in their areas. Identifying sites for wind machine clusters (wind farms) involves more than just finding a location with a suitable wind resource. Consideration must also be given to the proximity of sites to existing transmission lines, environmental impacts, aesthetics, and legal concerns as well as the availability of and alternative uses for the land. These issues have made it increasingly difficult for utilities to bring conventional power plants on-line quickly. Utilities are now required, however, to give careful consideration to specific legal, social, and environmental questions raised by the siting of wind energy conversion systems.

  15. A dual-cathode electro-Fenton oxidation coupled with anodic oxidation system used for 4-nitrophenol degradation.

    Science.gov (United States)

    Chu, Y Y; Qian, Y; Wang, W J; Deng, X L

    2012-01-15

    The degradation of 4-nitrophenol was investigated using a novel electrochemical oxidation system, in which the anodic oxidation at Ti/SnO(2)-Sb(2)O(5)-IrO(2) electrode and the electro-Fenton oxidation with two cathodes were involved. In this system, gas diffusion electrode (GDE) was used to generate H(2)O(2) by O(2) reduction and graphite electrode was employed for the reduction of Fe(3+) regenerating Fe(2+). When the potential values of GDE and graphite cathode were controlled at -0.80 and -0.10 V/SCE respectively, the optimum Fe(2+) concentration for 4-nitrophenol degradation was about 0.10mM, much lower than the concentration of 0.25 mM obtained in the single-cathode system. Due to the combination of electro-Fenton oxidation and anodic oxidation, an effective degradation and a high mineralization current efficiency (MCE) were achieved. After 600 min treatment, 74.5% of the original TOC was removed by the dual-cathode oxidation system. Moreover, it was confirmed that 57.0% of the original nitrogen could be removed in gaseous form from the simulated wastewater. These results indicate that this electrochemical oxidation process might provide an alternative for the degradation of organic pollutants. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Development of Hardware Dual Modality Tomography System

    Directory of Open Access Journals (Sweden)

    R. M. Zain

    2009-06-01

    Full Text Available The paper describes the hardware development and performance of the Dual Modality Tomography (DMT system. DMT consists of optical and capacitance sensors. The optical sensors consist of 16 LEDs and 16 photodiodes. The Electrical Capacitance Tomography (ECT electrode design use eight electrode plates as the detecting sensor. The digital timing and the control unit have been developing in order to control the light projection of optical emitters, switching the capacitance electrodes and to synchronize the operation of data acquisition. As a result, the developed system is able to provide a maximum 529 set data per second received from the signal conditioning circuit to the computer.

  17. USING REGIONAL RENEWABLE ENERGY RESOURSES FOR HEATING SUPPLY SYSTEMS

    Directory of Open Access Journals (Sweden)

    O. M. Pshinko

    2017-02-01

    Full Text Available Purpose. The study analyzed the possibility and conditions for the effective operation of heating systems during the transition of the heat-generating capacity to biofuels energy. The straw of cereal crops, which are prevailing in Dnipro region, is used for this. The main purpose is scientific calculation of opportunities and cost of specific measures for such a transition. As an example it was taken the boiler-room of campus at Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan (DNURT that consumes natural gas. Methodology. The work analyses the legislative base of Ukraine, which promotes the using of renewable energy sources as fuel, as well as the incentive mechanisms for the development of this trend. The paper identifies opportunities of Prydniprovsk region to ensure straw supply for the boiler-room. Cost parameters of cargo transportation on the territory of Ukraine in 2016, which depend on the distance and the size of the trucks, are analysed. These indicators, as well as indicators related to its purchase, are considered together with energy potential of using the straw as fuel. Findings. With existing in Ukraine (as of 2016 the grain yielding capacity in the agriculture and cost indicators in the field of transportations, the transition of capacity share to biofuel is sufficiently profitable. The thermal power unit cost can be reduced fourfold. Originality. For the first time it is proposed to use the new integrated approaches to assess the cost of thermal power unit boiler with its transition to the use of renewable energy sources. The authors also proposed a new logistics delivery of these sources to the place of their application. From a technical and cost points of view it was determined the optimal order of capacity transfer for new renewable sources of energy in a given region depending on the structure of areas under crops and their productivity. Originality. The introduction of the

  18. Dual-Energy CT of Rectal Cancer Specimens

    DEFF Research Database (Denmark)

    Al-Najami, Issam; Beets-Tan, Regina G H; Madsen, Gunvor

    2016-01-01

    BACKGROUND: An accurate method to assess malignant lymph nodes in the mesorectum is needed. Dual-energy CT scans simultaneously with 2 levels of energy and thereby provides information about tissue composition based on the known effective Z value of different tissues. Each point investigated...... is represented by a certain effective Z value, which allows for information on its composition. OBJECTIVE: We wanted to standardize a method for dual-energy scanning of rectal specimens to evaluate the sensitivity and specificity of benign versus malignant lymph node differentiation. Histopathological evaluation...... cancer. MAIN OUTCOME MEASURES: We measured accuracy of differentiating benign from malignant lymph nodes by investigating the following: 1) gadolinium, iodine, and water concentrations in lymph nodes; 2) dual-energy ratio; 3) dual-energy index; and 4) effective Z value. RESULTS: Optimal discriminations...

  19. Initial Experience of Using Dual-Energy CT with an Iodine Overlay Image for Hand Psoriatic Arthritis: Comparison Study with Contrast-enhanced MR Imaging.

    Science.gov (United States)

    Fukuda, Takeshi; Umezawa, Yoshinori; Tojo, Shinjiro; Yonenaga, Takenori; Asahina, Akihiko; Nakagawa, Hidemi; Fukuda, Kunihiko

    2017-07-01

    Purpose To determine the feasibility of dual-energy (DE) computed tomography (CT) with an iodine overlay image (IOI) for evaluation of psoriatic arthritis in the hand. Materials and Methods Approval from the institutional ethics committee and written informed consent from all patients were obtained. This prospective study included 16 patients who had psoriasis with finger joint symptoms from January 2015 to January 2016. Contrast material-enhanced (CE) DE CT and 1.5-T CE magnetic resonance (MR) imaging were performed within 1 month of each other. DE CT was performed with a tube voltage of 80 kV and 140 kV with use of a 0.4-mm tin filter. Images acquired with both modalities were evaluated by two radiologists independently by using a semiquantitative scoring system. Interreader agreement was calculated for each modality: Weighted κ values were calculated for synovitis, flexor tenosynovitis, and extensor peritendonitis, and κ values were calculated for periarticular inflammation. With consensus scores and CE MR images as the reference, the sensitivity and specificity of IOI DE CT for inflammatory lesions were calculated. Statistical analysis of discordant readings was performed by using the McNemar test. Results Interreader agreement for inflammatory lesions was excellent or good (weighted κ = 0.83 and κ = 0.75 in IOI DE CT; weighted κ = 0.81 and κ = 0.87 in CE MR imaging). The sensitivity and specificity of IOI DE CT were 0.78 and 0.87, respectively. Total agreement was 86.3%; however, there were significantly more lesions detected with IOI DE CT than with CE MR imaging alone (134 vs 20 lesions in 1120 evaluated items; P < .001). Sixty-nine percent of the abnormalities detected with IOI DE CT alone were located in distal interphalangeal joints. Conclusion IOI DE CT is a new imaging modality that may be useful for evaluating psoriatic arthritis in the hand, particularly in the detection of inflammatory lesions in small joints, and may be more useful than CE MR

  20. Including the effect of motion artifacts in noise and performance analysis of dual-energy contrast-enhanced mammography.

    Science.gov (United States)

    Allec, N; Abbaszadeh, S; Scott, C C; Lewin, J M; Karim, K S

    2012-12-21

    In contrast-enhanced mammography (CEM), the dual-energy dual-exposure technique, which can leverage existing conventional mammography infrastructure, relies on acquiring the low- and high-energy images using two separate exposures. The finite time between image acquisition leads to motion artifacts in the combined image. Motion artifacts can lead to greater anatomical noise in the combined image due to increased mismatch of the background tissue in the images to be combined, however the impact has not yet been quantified. In this study we investigate a method to include motion artifacts in the dual-energy noise and performance analysis. The motion artifacts are included via an extended cascaded systems model. To validate the model, noise power spectra of a previous dual-energy clinical study are compared to that of the model. The ideal observer detectability is used to quantify the effect of motion artifacts on tumor detectability. It was found that the detectability can be significantly degraded when motion is present (e.g., detectability of 2.5 mm radius tumor decreased by approximately a factor of 2 for translation motion on the order of 1000 μm). The method presented may be used for a more comprehensive theoretical noise and performance analysis and fairer theoretical performance comparison between dual-exposure techniques, where motion artifacts are present, and single-exposure techniques, where low- and high-energy images are acquired simultaneously and motion artifacts are absent.

  1. Dual energy computer tomography. Objectve dosimetry, image quality and dose efficiency; Dual Energy Computertomographie. Objektive Dosimetrie, Bildqualitaet und Dosiseffizienz

    Energy Technology Data Exchange (ETDEWEB)

    Schenzle, Jan Christian

    2012-05-24

    The aim of the present studies was an objective reflection of newly developed methods of modern imaging techniques concerning radiation exposure to the human body. Dual Source computed tomography has opened up a broad variety of new diagnostic possibilities. Using two X-ray sources with an angular offset of about 90 in a single gantry, images with a high spatiotemporal resolution can be achieved, for example in patients suffering acute chest pain. The Dual Energy Mode is based on the acquisition of two data sets with two different X-ray spectra which make it possible to identify certain substances with different spectral properties like bone, iodine or other organic material. [6-17] There is no doubt that this technical innovation will make an essential contribution to clinical diagnostics, but it remained to be proven that there is no additional dose. An anthropomorphic Phantom and thermoluminiscent detectors were used to objectively quantify the radiation dose resulting from the different examination protocols. For Dual Energy CT examinations, it was possible to verify dose neutrality in combination with comparable image quality and even improved contrast to noise ratio. Nowadays, this protocol is used in clinical routine examinations, e.g. for the evaluation of pulmonary embolism. A milestone in dose reduction was reached with modern triple rule out protocols. Causes of acute chest pain such as heart attack, pulmonary embolism or aortic rupture can be differentiated in a single examination with a high precision and a fractional amount of dose compared to conventional methods.

  2. Flow Time Analysis of Load Management Late Arrival Discrete Time Queueing System with Dual Service Rate Using Hypogeometrical Distribution

    Directory of Open Access Journals (Sweden)

    Syed Asif Ali Shah

    2012-01-01

    Full Text Available Flow time analysis is a powerful concept to analyze the flow time of any arriving customer in any system at any instant. A load management mechanism can be employed very effectively in any queueing system by utilizing a system which provides probability of dual service rate. In this paper, we develop and demonstrate the flow and service processes transition diagram to determine the flow time of a customer in a load management late arrival state dependent finite discrete time queueing system with dual service rate where customers are hypogeometrically distributed. We compute the probability mass function of each starting state and total probability mass function. The obtained analytical results are validated with simulation results for varying values of arrival and service probabilities.

  3. Suspension criteria for dual energy X ray absorptiometry.

    Science.gov (United States)

    McLean, I D

    2013-02-01

    The use of dual-energy X-ray absorptiometry (DXA) units primarily for the assessment of fracture risk and in the diagnosis of osteoporosis is ubiquitous in Europe and ever-expanding in its implementation worldwide. DXA is known for its reported low radiation dose and precision in the determination of bone mineral density. However, the use of simple suspension criteria, as proposed in the new EC report RP-162, will identify units that are unfit for useful and safe diagnosis. Such suspension levels, however, are not a substitute for regular maintenance, quality control testing and optimisation of clinical outcomes.

  4. Philosophical aspects of dual use technologies.

    Science.gov (United States)

    Pustovit, Svitlana V; Williams, Erin D

    2010-03-01

    The term dual use technologies refers to research and technology with the potential both to yield valuable scientific knowledge and to be used for nefarious purposes with serious consequences for public health or the environment. There are two main approaches to assessing dual use technologies: pragmatic and metaphysical. A pragmatic approach relies on ethical principles and norms to generate specific guidance and policy for dual use technologies. A metaphysical approach exhorts us to the deeper study of human nature, our intentions, goals, values ideals and social relations when considering dual use technology. Use of science and technology (S and T) is determined by two components of human nature: human intentions and choices. We have drawn a distinction between specific measures, goals and intentions with respect to technologies in order to show that moral judgment about technologies must precede their use. Understanding of our intentionality and values, and our moral ideals, as a measurable, tangible part of the real world is important for the prevention of any possible harm from S and T. In the context of dual use technologies, we stress the importance of three main understandings of human nature: vulnerability, responsibility and narrative identity. These can become a strong ontological "antidote" to technology's poisoning of modern man. Each new technology can be measured and compared with man's values, traditions and societal norms. This can be done bearing in mind the concept that human nature is not dualistic, but pluralistic. A system of ethical principles that includes the principles of good intentions, the correspondence of goals and means, the balancing of risks and benefits, simplicity, and contextuality, will help ensure that technologies are more humanistic and friendly to human beings.

  5. Modeling energy market dynamics using discrete event system simulation

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Alcaraz, G. [Department of Electrical and Electronics Engineering, Instituto Tecnologico de Morelia, Av. Tecnologico 1500, Col. Lomas de Santiaguito 58120, Morelia Michoacan (Mexico); Sheble, G.B. [Department of Electrical and Computer Engineering, Portland State University, Portland, OR 97207-0751 (United States)

    2009-10-15

    This paper proposes the use of Discrete Event System Simulation to study the interactions among fuel and electricity markets and consumers, and the decision-making processes of fuel companies (FUELCOs), generation companies (GENCOs), and consumers in a simple artificial energy market. In reality, since markets can reach a stable equilibrium or fail, it is important to observe how they behave in a dynamic framework. We consider a Nash-Cournot model in which marketers are depicted as Nash-Cournot players that determine supply to meet end-use consumption. Detailed engineering considerations such as transportation network flows are omitted, because the focus is upon the selection and use of appropriate market models to provide answers to policy questions. (author)

  6. Evaluating the sustainability of an energy supply system using renewable energy sources: An energy demand assessment of South Carolina

    Science.gov (United States)

    Green, Cedric Fitzgerald

    run the Sustainable Systems Analysis Algorithm (SSAA) and the multi-criteria decision analysis (MCDA) decision models. The following alternative energy sources for electricity (kilo- and megawatt output) will be assessed in this paper: solar, biomass and biofuels, hydro, geothermal, onshore wind, offshore wind, tidal, and natural gas. The SSAA methodology, in conjunction with the MCDA model techniques, will be used to obtain sustainable, alternative energy source system options; the system will attempt to balance its three linked aspects (environmental, economic, and technical). The results, based on the Sustainability Directive three-dimensional vector calculations from each alternative energy source option, are presented in this paper. Moving towards sustainability is a dynamically changing process, and the SSAA methodology is a synergist for system modifications that strives for continuous improvement toward the Ideal Sustainability Directive.

  7. Collective effects for long bunches in dual harmonic RF systems

    Institute of Scientific and Technical Information of China (English)

    AN Shi-Zhong; Klaus Bongardt; Rudolf Maier; TANG Jing-Yu; ZHANG Tian-Jue

    2008-01-01

    The storage of long bunches for large time intervals needs flattened stationary buckets with a large bucket height.Collective effects from the space charge and resistive impedance are studied by looking at the incoherent particle motion for the matched and mismatched bunches.Increasing the RF amplitude with particle number provides r.m.s wise matching for modest intensities.The incoherent motion of large amplitude particles depends on the details of the RF system.The resulting debunching process is a combination of the too small full RF acceptance together with the mismatch,enhanced by the collective effects.Irregular single particle motion is not associated with the coherent dipole instability.For the stationary phase space distribution of the Hofmann-Pedersen approach and for the dual harmonic RF system,stability limits are presented,which are too low if using realistic input distributions.For single and dual harmonic RF system with d=0.31,the tracking results are shown for intensities,by a factor of 3 above the threshold values.Small resistive impedances lead to coherent oscillations around the equilibrium phase value,as energy loss by resistive impedance is compensated by the energy gain of the RF system.

  8. Dictionary-based image denoising for dual energy computed tomography

    Science.gov (United States)

    Mechlem, Korbinian; Allner, Sebastian; Mei, Kai; Pfeiffer, Franz; Noël, Peter B.

    2016-03-01

    Compared to conventional computed tomography (CT), dual energy CT allows for improved material decomposition by conducting measurements at two distinct energy spectra. Since radiation exposure is a major concern in clinical CT, there is a need for tools to reduce the noise level in images while preserving diagnostic information. One way to achieve this goal is the application of image-based denoising algorithms after an analytical reconstruction has been performed. We have developed a modified dictionary denoising algorithm for dual energy CT aimed at exploiting the high spatial correlation between between images obtained from different energy spectra. Both the low-and high energy image are partitioned into small patches which are subsequently normalized. Combined patches with improved signal-to-noise ratio are formed by a weighted addition of corresponding normalized patches from both images. Assuming that corresponding low-and high energy image patches are related by a linear transformation, the signal in both patches is added coherently while noise is neglected. Conventional dictionary denoising is then performed on the combined patches. Compared to conventional dictionary denoising and bilateral filtering, our algorithm achieved superior performance in terms of qualitative and quantitative image quality measures. We demonstrate, in simulation studies, that this approach can produce 2d-histograms of the high- and low-energy reconstruction which are characterized by significantly improved material features and separation. Moreover, in comparison to other approaches that attempt denoising without simultaneously using both energy signals, superior similarity to the ground truth can be found with our proposed algorithm.

  9. Power Quality Improvement Wind Energy System Using Cascaded Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    J.S. Sathiyanarayanan

    2013-02-01

    Full Text Available In this paper, a wind energy conversion system based on a cascaded H-bridgemultilevel inverter (CHBMLI topology has been proposed to be used for the grid interface of largesplit winding alternators (SWAs. A new method has been suggested for the generation of referencecurrents for the voltage source inverter (VSI depending upon the available wind power. TheCHBMLI has been used as a VSI and operated in a current control mode order to achieve theobjectives of real power injection and load compensation (power factor correction, load balancing,and harmonic compensation based on the proposed reference generation scheme. In the fieldexcitation control of SWA provides a single means vary the dc link voltages of all the CHBssimultaneously and proportionately.

  10. Computed tomography with single-shot dual-energy sandwich detectors

    Science.gov (United States)

    Kim, Seung Ho; Youn, Hanbean; Kim, Daecheon; Kim, Dong Woon; Jeon, Hosang; Kim, Ho Kyung

    2016-03-01

    Single-shot dual-energy sandwich detector can produce sharp images because of subtraction of images from two sub-detector layers, which have different thick x-ray converters, of the sandwich detector. Inspired by this observation, the authors have developed a microtomography system with the sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The preliminary results show that the bone-enhanced images reconstructed with the subtracted projection data are better in visibility of bone details than the conventionally reconstructed images. In addition, the bone-enhanced images obtained from the sandwich detector are relatively immune to the artifacts caused by photon starvation. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone imaging.

  11. FLUKA Monte Carlo for Basic Dosimetric Studies of Dual Energy Medical Linear Accelerator

    Directory of Open Access Journals (Sweden)

    K. Abdul Haneefa

    2014-01-01

    Full Text Available General purpose Monte Carlo code for simulation of particle transport is used to study the basic dosimetric parameters like percentage depth dose and dose profiles and compared with the experimental measurements from commercial dual energy medical linear accelerator. Varian Clinac iX medical linear accelerator with dual energy photon beams (6 and 15 MV is simulated using FLUKA. FLAIR is used to visualize and edit the geometry. Experimental measurements are taken for 100 cm source-to-surface (SSD in 50 × 50 × 50 cm3 PTW water phantom using 0.12 cc cylindrical ionization chamber. Percentage depth dose for standard square field sizes and dose profiles for various depths are studied in detail. The analysis was carried out using ROOT (a DATA analysis frame work developed at CERN system. Simulation result shows good agreement in percentage depth dose and beam profiles with the experimental measurements for Varian Clinac iX dual energy medical linear accelerator.

  12. First-Order Acoustic Wave Equation Reverse Time Migration Based on the Dual-Sensor Seismic Acquisition System

    Science.gov (United States)

    You, Jiachun; Liu, Xuewei; Wu, Ru-Shan

    2017-03-01

    We analyze the mathematical requirements for conventional reverse time migration (RTM) and summarize their rationale. The known information provided by current acquisition system is inadequate for the second-order acoustic wave equations. Therefore, we introduce a dual-sensor seismic acquisition system into the coupled first-order acoustic wave equations. We propose a new dual-sensor reverse time migration called dual-sensor RTM, which includes two input variables, the pressure and vertical particle velocity data. We focus on the performance of dual-sensor RTM in estimating reflection coefficients compared with conventional RTM. Synthetic examples are used for the study of estimating coefficients of reflectors with both dual-sensor RTM and conventional RTM. The results indicate that dual-sensor RTM with two inputs calculates amplitude information more accurately and images structural positions of complex substructures, such as the Marmousi model, more clearly than that of conventional RTM. This shows that the dual-sensor RTM has better accuracy in backpropagation and carries more information in the directivity because of particle velocity injection. Through a simple point-shape model, we demonstrate that dual-sensor RTM decreases the effect of multi-pathing of propagating waves, which is helpful for focusing the energy. In addition, compared to conventional RTM, dual-sensor RTM does not cause extra memory costs. Dual-sensor RTM is, therefore, promising for the computation of multi-component seismic data.

  13. Dual-Energy Imaging of Urate Crystals in Gout Using Dual-Source CT%双源CT双能量成像对痛风诊断价值的初步研究

    Institute of Scientific and Technical Information of China (English)

    靳国庆; 王东林; 王振杰; 李麦福

    2013-01-01

    目的 探讨双源CT双能量成像(DECT)技术在痛风患者四肢关节尿酸盐结晶的显示能力及其临床应用价值,并就DECT对痛风的疗效进行初步评估.方法 病例组为临床确诊为痛风或高尿酸血症患者50例,男46例,女4例,足45例,手5例;对照组为非痛风患者10例,两组性别及年龄比较,差异无统计学意义(P年龄=0.234,P性别=0.612,P>0.05).分别对其足/手行DECT非增强扫描及薄层重组(0.75 mm),将原始数据输送加载入Du-al-EnergyGOUT软件内进行图像后处理,比较病例组和对照组患者尿酸盐沉积的差异以及DECT检测尿酸盐沉积部位与临床评估的差异.采用t检验,Fisher精确概率进行统计学分析.结果 病例组均获得了较满意的DECT图像,显示尿酸盐结晶沉积478处,最少2处,最多24处,以足踝部病灶最多;对照组均未见尿酸盐结晶沉积,检出率两组相比,差异有显著统计学意义(P =0.00012,P<0.001).结论 DECT技术可明确显示尿酸盐结晶沉积,对于关节痛及疑似痛风患者,尤其是痛风早期有较高的检出率.经引导下穿刺抽吸,与CT像一致,具有较高的临床应用价值,可作为痛风筛选的常规检查项目,但就DECT对痛风疗效的评估有待于收集更多的病例进一步研究.%Objective To evaluate the capabilities and efficacy of dual energy CT (DECT) in displaying urate crystals in extremities joints of gout. Methods In study group, 50 clinically confirmed patients (46 males and 4 females) with gout or hyperuricemia were collected. Gout involved feet in 45 cases,hands in 5. In control group, 10 normal volunteers were collected. There was no significant difference between the two groups on age and gender (Page =0. 234,Pgendex= 0.612,P >0.05). DECT noncontrast scanning and thin sliced (0.75 mm) reconstruction of foot / hand were performed. The urate deposition were compared between 2 groups. Results The high quality dual energy images were obtained in all

  14. Energy efficient hybrid computing systems using spin devices

    Science.gov (United States)

    Sharad, Mrigank

    Emerging spin-devices like magnetic tunnel junctions (MTJ's), spin-valves and domain wall magnets (DWM) have opened new avenues for spin-based logic design. This work explored potential computing applications which can exploit such devices for higher energy-efficiency and performance. The proposed applications involve hybrid design schemes, where charge-based devices supplement the spin-devices, to gain large benefits at the system level. As an example, lateral spin valves (LSV) involve switching of nanomagnets using spin-polarized current injection through a metallic channel such as Cu. Such spin-torque based devices possess several interesting properties that can be exploited for ultra-low power computation. Analog characteristic of spin current facilitate non-Boolean computation like majority evaluation that can be used to model a neuron. The magneto-metallic neurons can operate at ultra-low terminal voltage of ˜20mV, thereby resulting in small computation power. Moreover, since nano-magnets inherently act as memory elements, these devices can facilitate integration of logic and memory in interesting ways. The spin based neurons can be integrated with CMOS and other emerging devices leading to different classes of neuromorphic/non-Von-Neumann architectures. The spin-based designs involve `mixed-mode' processing and hence can provide very compact and ultra-low energy solutions for complex computation blocks, both digital as well as analog. Such low-power, hybrid designs can be suitable for various data processing applications like cognitive computing, associative memory, and currentmode on-chip global interconnects. Simulation results for these applications based on device-circuit co-simulation framework predict more than ˜100x improvement in computation energy as compared to state of the art CMOS design, for optimal spin-device parameters.

  15. Topography and Vegetation Characterization using Dual-Wavelength Airborne Lidar

    Science.gov (United States)

    Neuenschwander, A. L.; Bradford, B.; Magruder, L. A.

    2014-12-01

    Monitoring Earth surface dynamics at an ever increasing resolution has helped to support the characterization of local topography, including vegetated and urban environments. Airborne remote sensing using light detection and ranging (LIDAR) is naturally suited to characterize vegetation and landscapes as it provides detailed three-dimensional spatial data with multiple elevation recordings for each laser pulse. The full waveform LIDAR receiver is unique in this aspect as it can capture and record the complete temporal history of the reflected signal, which contains detailed information about the structure of the objects and ground surfaces illuminated by the beam. This study examines the utility of co-collected, dual-wavelength, full waveform LIDAR data to characterize vegetation and landscapes through the extraction of waveform features, including total waveform energy, canopy energy distribution, and foliage penetration metrics. Assessments are performed using data collected in May 2014 over Monterey, CA, including the Naval Postgraduate School campus area as well as the Point Lobos State Natural Reserve situated on the Monterey coast. The surveys were performed with the Chiroptera dual-laser LIDAR mapping system from Airborne Hydrography AB (AHAB), which can collect both green (515nm) and near infrared (1064nm) waveforms simultaneously. Making use of the dual waveforms allows for detailed characterization of the vegetation and landscape not previously possible with airborne LIDAR.

  16. Dual-energy imaging of bone marrow edema on a dedicated multi-source cone-beam CT system for the extremities

    Science.gov (United States)

    Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

    2015-03-01

    Purpose: Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods: Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results: For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix

  17. Long-term affected energy production of waste to energy technologies identified by use of energy system analysis.

    Science.gov (United States)

    Münster, M; Meibom, P

    2010-12-01

    Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO(2) quota costs are analysed. It is demonstrated that the waste incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste proves to always affect a combination of technologies. What is affected varies among the different Waste-to-Energy technologies and is furthermore dependent on the CO(2) quota costs and on the geographical scope. The necessity for investments in flexibility measures varies with the different technologies such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Features of dual-energy X-ray computed tomography

    Science.gov (United States)

    Torikoshi, M.; Tsunoo, T.; Ohno, Y.; Endo, M.; Natsuhori, M.; Kakizaki, T.; Ito, N.; Uesugi, K.; Yagi, N.

    2005-08-01

    We proposed dual-energy X-ray CT for direct measurement of electron densities to make treatment planning for heavy ion radiotherapy more accurate. The accuracy was proved to be about 1% using synchrotron radiation in previous experiments carried out at SPring-8 and PF-AR. The electron densities of some porcine organs were measured in this method at SPring-8, and compared with data of ICRU Report. Besides, the atomic number of the object is also obtained as a byproduct. Comparing the CT-number given in conventional CT scanning is an important information. Images of the electron density and atomic number may give new information to medical diagnosis.

  19. Evaluation of image quality and radiation dose using gold nanoparticles and other clinical contrast agents in dual-energy Computed Tomography (CT): CT abdomen phantom

    Science.gov (United States)

    Zukhi, J.; Yusob, D.; Tajuddin, A. A.; Vuanghao, L.; Zainon, R.

    2017-05-01

    The aim of this study was to evaluate the image quality and radiation dose using commercial gold nanoparticles and clinical contrast agents in dual-energy Computed Tomography (CT). Five polymethyl methacrylate (PMMA) tubes were used in this study, where four tubes were filled with different contrast agents (barium, iodine, gadolinium, and gold nanoparticles). The fifth tube was filled with water. Two optically stimulated luminescence dosimeters (OSLD) were placed in each tube to measure the radiation dose. The tubes were placed in a fabricated adult abdominal phantom of 32 cm in diameter using PMMA. The phantom was scanned using a DECT at low energy (80 kV) and high energy (140 kV) with different pitches (0.6 mm and 1.0 mm) and different slice thickness (3.0 mm and 5.0 mm). The tube current was applied automatically using automatic exposure control (AEC) and tube current modulation recommended by the manufacturer (CARE Dose 4D, Siemens, Germany). The contrast-to-noise ratio (CNR) of each contrast agent was analyzed using Weasis software. Gold nanoparticles has highest atomic number (Z = 79) than barium (Z = 56), iodine (Z = 53) and gadolinium (Z = 64). The CNR value of each contrast agent increases when the slice thickness increases. The radiation dose obtained from this study decreases when the pitch increases. The optimal imaging parameters for gold nanoparticles and other clinical contrast agents is obtained at pitch value of 1.0 mm and slice thickness of 5.0 mm. Low noise and low radiation dose obtained at these imaging parameters. The optimal imaging parameters obtained in this study can be applied in multiple contrast agents imaging.

  20. Dual-Readout Calorimetry for High-Quality Energy

    CERN Multimedia

    During the past seven years, the DREAM collaboration has systematically investigated all factors that determine and limit the precision with which the properties of hadrons and jets can be measured in calorimeters. Using simultaneous detection of the deposited energy and the Cerenkov light produced in hadronic shower development ${(dual}$ ${readout}$), the fluctuations in the electromagnetic shower fraction could be measured event by event their effects on signal linearity, response function and energy resolution eliminated. Detailed measurement of the time structure of the signals made it possible to measure the contirbutions of nuclear evaporation neutrons to the signals and thus reduce the effects of fluctuations in "invisible energy". We are now embarking on the construction of a full-scale calorimeter which incorporates all these elements and which should make it possible to measure the four-vectors of both electrons, hadrons and jets with very high precision, in an instrument that can be simply calibrat...

  1. A Dual-Linear Kalman Filter for Real-Time Orientation Determination System Using Low-Cost MEMS Sensors.

    Science.gov (United States)

    Zhang, Shengzhi; Yu, Shuai; Liu, Chaojun; Yuan, Xuebing; Liu, Sheng

    2016-02-20

    To provide a long-time reliable orientation, sensor fusion technologies are widely used to integrate available inertial sensors for the low-cost orientation estimation. In this paper, a novel dual-linear Kalman filter was designed for a multi-sensor system integrating MEMS gyros, an accelerometer, and a magnetometer. The proposed filter precludes the impacts of magnetic disturbances on the pitch and roll which the heading is subjected to. The filter can achieve robust orientation estimation for different statistical models of the sensors. The root mean square errors (RMSE) of the estimated attitude angles are reduced by 30.6% under magnetic disturbances. Owing to the reduction of system complexity achieved by smaller matrix operations, the mean total time consumption is reduced by 23.8%. Meanwhile, the separated filter offers greater flexibility for the system configuration, as it is possible to switch on or off the second stage filter to include or exclude the magnetometer compensation for the heading. Online experiments were performed on the homemade miniature orientation determination system (MODS) with the turntable. The average RMSE of estimated orientation are less than 0.4° and 1° during the static and low-dynamic tests, respectively. More realistic tests on two-wheel self-balancing vehicle driving and indoor pedestrian walking were carried out to evaluate the performance of the designed MODS when high accelerations and angular rates were introduced. Test results demonstrate that the MODS is applicable for the orientation estimation under various dynamic conditions. This paper provides a feasible alternative for low-cost orientation determination.

  2. Enhanced electrophoretic motion using supercapacitor-based energy storage system.

    Science.gov (United States)

    Liu, Ran; Wong, Flory; Duan, Wentao; Sen, Ayusman

    2013-12-23

    Electrophoretic motion at low potentials is facilitated by redox chemistry occurring in a supercapacitor-based electrochemical energy storage system during charge and discharge. We show that MnO2 -modified electrodes can effectively alleviate the electrode surface polarization, the main factor that leads to inefficient electrophoresis at low voltages. A self-powered electrophoretic system based on a discharging battery has been also fabricated.

  3. Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.

    Science.gov (United States)

    Cai, Xiangran; Zhou, Qingchun; Yu, Juan; Xian, Zhaohui; Feng, Youzhen; Yang, Wencai; Mo, Xukai

    2014-10-01

    To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components. A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared. Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Linking Energy- and Land-Use Systems: Energy Potentials and Environmental Risks of Using Agricultural Residues in Tanzania

    Directory of Open Access Journals (Sweden)

    Julia C. Terrapon-Pfaff

    2012-02-01

    Full Text Available This paper attempts to assess whether renewable energy self-sufficiency can be achieved in the crop production and processing sector in Tanzania and if this could be accomplished in an environmentally sustainable manner. In order to answer these questions the theoretical energy potential of process residues from commercially produced agricultural crops in Tanzania is evaluated. Furthermore, a set of sustainability indicators with focus on environmental criteria is applied to identify risks and opportunities of using these residues for energy generation. In particular, the positive and negative effects on the land-use-system (soil fertility, water use and quality, biodiversity, etc. are evaluated. The results show that energy generation with certain agricultural process residues could not only improve and secure the energy supply but could also improve the sustainability of current land-use practices.

  5. Dual-purpose laser irradiation and perfusion testing system for in-vitro experiments using cultured trabecular meshwork endothelial cells

    Science.gov (United States)

    Rivera, Brian K.; Roberts, Cynthia J.; Weber, Paul A.

    1998-06-01

    The means by which Argon laser trabeculoplasty (ALT) lowers intraocular pressure (IOP) is a matter of debate. Mechanical and biological laser-tissue interaction theories have been proposed. To investigate the effect laser irradiation has upon the aqueous outflow facility of trabecular meshwork (TM) cells, a suitable in-vitro model is required. Therefore the purpose of this study was to design, construct, and validate a laser irradiation and perfusion testing apparatus. The system was designed to utilize cultured TM cells seeded onto filter supports. Outflow facility will be quantified by calculating the hydraulic conductivity of the monolayer. An appropriate filter support was located, and its perfusion characteristics determined using water. Afterwards, the steady state perfusion flow rate of the filter was ascertained to be 0.096 plus or minus 0.008 ml/min when culture medium is used. Following these tests a single, baseline perfusion experiment was conducted using a TM cell monolayer. Analysis of the data produced a baseline hydraulic conductivity of 0.673 plus or minus 0.076 (mu) l/min/mm Hg/cm2, well within the range found in previous reports. A dual purpose, in vitro-cellular perfusion and laser irradiation testing apparatus has been developed, tested and validates using known baseline cellular perfusion and laser irradiation testing apparatus has been developed, tested, and validated using known baseline cellular perfusion values. Future experiments will be conducted to verify these initial findings, and further experiments will be conducted using Argon laser irradiation. The response of the TM cell monolayer will then be compared to the baseline figures.

  6. CH2 Energy Harvesting Systems: Economic Use and Efficiency

    Directory of Open Access Journals (Sweden)

    Chun Cheung

    2012-11-01

    Full Text Available This paper looks at the City of Melbourne's new office development CH2 as a case study of world class energy performance. In particular, the integrated design of conventionally independent systems has led to the potential to deliver significant savings to the Council and to deliver better environmental conditions to building occupants that in turn may contribute to satisfaction, well-being and productivity. It is concluded that this project has the potential to be an iconic example of effective implementation of ESD (environmental sustainable design principles and therefore act as a demonstration project to others. Energy efficiency of more than 50% of current benchmarks for Melbourne is effected. Energy harvesting is defined as arising from squander, waste and nature, which is a new concept introduced in this paper to better describe the design decision process.

  7. Differentiating calcium oxalate and hydroxyapatite stones in vivo using dual-energy CT and urine supersaturation and pH values.

    Science.gov (United States)

    Liu, Yu; Qu, Mingliang; Carter, Rickey E; Leng, Shuai; Ramirez-Giraldo, Juan Carlos; Jaramillo, Giselle; Krambeck, Amy E; Lieske, John C; Vrtiska, Terri J; McCollough, Cynthia H

    2013-12-01

    Knowledge of urinary stone composition can guide therapeutic intervention for patients with calcium oxalate (CaOx) or hydroxyapatite (HA) stones. In this study, we determined the accuracy of noninvasive differentiation of these two stone types using dual-energy CT (DECT) and urine supersaturation (SS) and pH values. Patients who underwent clinically indicated DECT scanning for stone disease and subsequent surgical intervention were enrolled. Stone composition was determined using infrared spectroscopy. DECT images were processed using custom-developed software that evaluated the ratio of CT numbers between low- and high-energy images. Clinical information, including patient age, gender, and urine pH and supersaturation profile, was obtained from electronic medical records. Simple and multiple logistic regressions were used to determine if the ratio of CT numbers could discriminate CaOx from HA stones alone or in conjunction with urine supersaturation and pH. Urinary stones (CaOx n = 43, HA n = 18) from 61 patients were included in this study. In a univariate model, DECT data, urine SS-HA, and urine pH had an area under the receiver operating characteristic curve of 0.78 (95% confidence interval [CI] 0.66-0.91, P = .016), 0.76 (95% CI 0.61-0.91, P = .003), and 0.60 (95% CI 0.44-0.75, P = .20), respectively, for predicting stone composition. The combination of CT data and the urinary SS-HA had an area under the receiver operating characteristic curve of 0.79 (95% CI 0.66-0.92, P = .007) for correctly differentiating these two stone types. DECT differentiated between CaOx and HA stones similarly to SS-HA, whereas pH was a poor discriminator. The combination of DECT and urine SS or pH data did not improve this performance. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  8. Separation of selected imidazole enantiomers using dual cyclodextrin system in micellar electrokinetic chromatography.

    Science.gov (United States)

    Wan Ibrahim, Wan Aini; Abd Wahib, Siti Munirah; Hermawan, Dadan; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

    2013-06-01

    Cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was developed for simultaneous enantioseparation of three imidazole drugs namely tioconazole, isoconazole and fenticonazole. Three easily available and inexpensive cyclodextrins namely 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CD) and heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) were evaluated to discriminate the six stereoisomers of the drugs. However, none of the three CDs gave a complete enantioseparation of the drugs. Effective enantioseparation of tioconazole, isoconazole and fenticonazole was achieved using a combination of 35 mM HP-γ-CD and 10 mM DM-β-CD as chiral selectors. The best separation using both HP-γ-CD and DM-β-CD (35 mM:10 mM) as chiral selectors were accomplished in background electrolyte (BGE) containing 35 mM phosphate buffer (pH 7.0), 50 mM sodium dodecyl sulfate (SDS) and 15% (v/v) acetonitrile at 27 kV and 30 °C with all peaks resolved in less than 15 min with resolutions, Rs 1.90-27.22 and peak efficiencies, N > 180 000. The developed method was linear over the concentration range of 25-200 mg l(-1) (r(2) > 0.998) and the detection limits (S/N = 3) of the three imidazole drugs were found to be 2.7-7.7 mg l(-1). The CD-MEKC method was successfully applied to the determination of the three imidazole drugs in spiked human urine sample and commercial cream formulation of tioconazole and isoconazole with good recovery (93.6-106.2%) and good RSDs ranging from 2.30-6.8%.

  9. Dual-Readout Calorimetry for High-Quality Energy Measurements

    CERN Document Server

    Wigmans, R

    2010-01-01

    During the past seven years, the DREAM Collaboration has systematically investigated all factors that determine and limit the precision with which the properties of hadrons and jets can be measured in calorimeters. Using simultaneous detection of the deposited energy and the Cerenkov light produced in hadronic shower development (dual readout), the fluctuations in the electromagnetic shower fraction could be measured event by event and their effects on signal linearity, response function and energy resolution eliminated. Detailed measurement of the time structure of the signals made it possible to measure the contributions of nuclear evaporation to the signals and thus reduce the effects of fluctuations in “invisible energy”. We are now embarking on the construction of a full-scale calorimeter which incorporates all these elements and which should make it possible to measure the four-vectors of both electrons, hadrons and jets with very high precision, in an instrument that can be simply calibrated with e...

  10. Energy transfer and dual cascade in kinetic magnetized plasma turbulence.

    Science.gov (United States)

    Plunk, G G; Tatsuno, T

    2011-04-22

    The question of how nonlinear interactions redistribute the energy of fluctuations across available degrees of freedom is of fundamental importance in the study of turbulence and transport in magnetized weakly collisional plasmas, ranging from space settings to fusion devices. In this Letter, we present a theory for the dual cascade found in such plasmas, which predicts a range of new behavior that distinguishes this cascade from that of neutral fluid turbulence. These phenomena are explained in terms of the constrained nature of spectral transfer in nonlinear gyrokinetics. Accompanying this theory are the first observations of these phenomena, obtained via direct numerical simulations using the gyrokinetic code AstroGK. The basic mechanisms that are found provide a framework for understanding the turbulent energy transfer that couples scales both locally and nonlocally.

  11. A study on the effects of a calcium drug on the bone mineral density (BMD) by using dual-energy X-ray Absorptiometry (DXA)

    Science.gov (United States)

    Kim, Eun-Hye; Kim, Ho-Sung; Dong, Kyung-Rae; Park, Yong-Soon; Chung, Woon-Kwan; Cho, Jae-Hwan

    2012-12-01

    Measurements of osteoporosis might contain errors caused by the calcium drug used in the prevention and the treatment of osteoporosis. This study conducted a lumbar spine phantom experiment to examine whether a calcium drug can influence the measured values of the bone mineral density (BMD) because of the drug taken by a real patient remaining undigested in the stomach. Dual-energy X-ray Absorptiometry (DXA) was used to measure the BMD for a calcium-drug in an equipment-dedicated lumbar spine phantom and 10 patients selected for the BMD measurement. Three types of drugs that are prescribed in actual clinical practice calcium drugs were used for the phantom experiment, and the drugs were divided into a fixed dose, 1/2 of the fixed dose, 1/4 of the fixed dose and 1/8 of the fixed dose. Without the drugs included, the phantom was scanned 60 times continuously to calculate the baseline BMD. The BMD was measured as the calcium drug coated with paraffin was placed in the lumbar vertebra 2 and the soft tissue region of the phantom. To determine when the drug was invisible to the naked eye are measured, the BMD at different drug dilutions. The measurements were conducted three times to calculate the mean. In the patient experiment, patients were selected who visited hospital after taking the drug before measuring the BMD. After a certain time had passed, the BMD was measured again to examine the difference in images and the change in BMD values due to the calcium-drug intake. The BMD measurements of lumbar 1-4 in the phantom were higher, with statistical significant, than the least significant change (LSC) in the bone region for all three drugs (Ca carbonate, Ca citrate and Ca cholecalciferol), showing a significant increase. On the other hand, there was no significant change in the soft tissue. When Ca Cholecalciferol was used in a fixed dose, the BMD of L2 increased by 11.6%, showing the largest increase among the drugs examined, but only a 2.8% increase in the BMD of L1

  12. MO-FG-204-03: Using Edge-Preserving Algorithm for Significantly Improved Image-Domain Material Decomposition in Dual Energy CT

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, W [Huazhong University of Science & Technology, Wuhan, Hubei (China); Niu, T [Zhejiang University, Hangzhou, Zhejiang (China); Xing, L [Stanford Univ School of Medicine, Stanford, CA (United States); Xiong, G; Elmore, K; Min, J [Dalio Institute of Cardiovascular Imaging NewYork-Presbyterian Hospital and, New York, NY (United States); Zhu, J; Wang, L [Huazhong University of Science and Technology, Wuhan, Hubei (China)

    2015-06-15

    Purpose: To significantly improve dual energy CT (DECT) imaging by establishing a new theoretical framework of image-domain material decomposition with incorporation of edge-preserving techniques. Methods: The proposed algorithm, HYPR-NLM, combines the edge-preserving non-local mean filter (NLM) with the HYPR-LR (Local HighlY constrained backPRojection Reconstruction) framework. Image denoising using HYPR-LR framework depends on the noise level of the composite image which is the average of the different energy images. For DECT, the composite image is the average of high- and low-energy images. To further reduce noise, one may want to increase the window size of the filter of the HYPR-LR, leading resolution degradation. By incorporating the NLM filtering and the HYPR-LR framework, HYPR-NLM reduces the boost material decomposition noise using energy information redundancies as well as the non-local mean. We demonstrate the noise reduction and resolution preservation of the algorithm with both iodine concentration numerical phantom and clinical patient data by comparing the HYPR-NLM algorithm to the direct matrix inversion, HYPR-LR and iterative image-domain material decomposition (Iter-DECT). Results: The results show iterative material decomposition method reduces noise to the lowest level and provides improved DECT images. HYPR-NLM significantly reduces noise while preserving the accuracy of quantitative measurement and resolution. For the iodine concentration numerical phantom, the averaged noise levels are about 2.0, 0.7, 0.2 and 0.4 for direct inversion, HYPR-LR, Iter- DECT and HYPR-NLM, respectively. For the patient data, the noise levels of the water images are about 0.36, 0.16, 0.12 and 0.13 for direct inversion, HYPR-LR, Iter-DECT and HYPR-NLM, respectively. Difference images of both HYPR-LR and Iter-DECT show edge effect, while no significant edge effect is shown for HYPR-NLM, suggesting spatial resolution is well preserved for HYPR-NLM. Conclusion: HYPR

  13. Energy Spectrum Extraction and Optimal Imaging via Dual-Energy Material Decomposition

    CERN Document Server

    Zhao, Wei; Zhang, Bo; Zhang, Qiude; Niu, Tianye

    2015-01-01

    Inferior soft-tissue contrast resolution is a major limitation of current CT scanners. The aim of the study is to improve the contrast resolution of CT scanners using dual-energy acquisition. Based on dual-energy material decomposition, the proposed method starts with extracting the outgoing energy spectrum by polychromatic forward projecting the material-selective images. The extracted spectrum is then reweighted to boost the soft-tissue contrast. A simulated water cylinder phantom with inserts that contain a series of six solutions of varying iodine concentration (range, 0-20 mg/mL) is used to evaluate the proposed method. Results show the root mean square error (RMSE) and mean energy difference between the extracted energy spectrum and the spectrum acquired using an energy-resolved photon counting detector(PCD), are 0.044 and 0.01 keV, respectively. Compared to the method using the standard energy-integrating detectors, dose normalized contrast-to-noise ratio (CNRD) for the proposed method are improved fro...

  14. Evaluation of femur of orchiectomized Guinea pigs by bone densitometry using dual-energy X-ray absorptiometry (DXA) and mechanical testing

    Energy Technology Data Exchange (ETDEWEB)

    Estanislau, Cristiane de Abreu; Rahal, Sheila Canavese; Araujo, Fabio Andre Pinheiro de, E-mail: crisestanislau@hotmail.co, E-mail: sheilacr@fmvz.unesp.b, E-mail: fabioandre@fmvz.unesp.b [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina, Veterinaria e Zootecnia. Dept. de Cirurgia e Anestesiologia Veterinaria; Sergio Swain Muller, E-mail: diretoria@fmb.unesp.b [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina, Veterinaria e Zootecnia. Dept. de Cirurgia e Ortopedia; Louzada, Mario Jefferson Quirino, E-mail: louzada@fmva.unesp.b [Universidade Estadual Paulista (UNESP), Aracatuba, SP (Brazil). Faculdade de Medicina Veterinaria; Estanislau, Caroline de Abreu, E-mail: caestanis@hotmail.co

    2010-03-15

    The aim of this study was to evaluate the effects of castration on bones in the male guinea pigs and to observe whether mechanical testing correlates with dual-energy X-ray absorptiometry (DXA). Twelve male guinea pigs (Cavia porcellus), aged 21-27 days, and with average initial weight of 279 grams were used. The animals were equally allocated to two groups: GI - orchiectomized animals and GII - intact control animals. They underwent euthanasia at seven months following surgery. DXA measurement was performed at the mid third of the right femoral diaphysis in the cortical region and at the left femoral neck in order to verify its correlation with results of mechanical testing. Three-point bending test of right femur and axial compression test of left femur were performed. Bone mineral density of GI was significantly lower only at femoral neck. No differences were observed in the maximum load values between GI and GII for both bending and axial compression tests. The bending test revealed lower bone stiffness in GI compared to GII, but in the axial compression test no differences between groups were observed. Only left femur showed positive correlation coefficient between maximum load and bone mineral density according to Pearson's correlation coefficient. The results suggest that hormonal deprivation in guinea pigs induces reduction of bone mineral density, especially in the femoral neck area and reduction of bone stiffness in the mid-femoral diaphysis. (author)

  15. Energy Efficiency of Inductive Energy Storage System Pulsed Power Generator Using Fast Recovery Diode

    Science.gov (United States)

    Go, Tomio; Kanesawa, Kyousuke; Yamazaki, Nobuyuki; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

    Characteristics of inductive energy storage system pulsed power generator with semiconductor opening switch (SOS) diodes are investigated with focusing on an energy transfer efficiency from the generator to the resistive load. Fast recovery diodes VMI K100UF were used as SOS and were connected in series and/or in parallel to realize a large current and a high output voltage. The output voltage increases with increasing circuit inductance L and/or primary capacitor capacitance C. The reverse pumping time also increases with LC value and is saturated to 100 ns at LC=50×10-15 HF. The pulse width of the output voltage increases gradually with increasing value of the LC multiplication. The energy transfer efficiency of the generator to the resistive load has a maximum value of 71% at C=4nF and L=12.6μH when the load resistance is 122 Ω. This value is almost two times larger than 56 Ω of the surge impedance Zs=√L/C and much smaller than impedance of the SOS diodes after interrupting the circuit current. The maximum energy transfer efficiency decreases from 71 to 32% with decreasing LC value from 50×10-15 to 1.2×10-15 HF.

  16. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Weast, T.; Shannon, L.

    1980-06-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  17. SIMULATION OF THE SYSTEMS WITH RENEWABLE ENERGY SOURCES USING HOMER SOFTWARE

    Directory of Open Access Journals (Sweden)

    FIRINCĂ S.D.

    2015-06-01

    Full Text Available This paper simulates by using the Homer software, a distributed energy system with capacity below 1 MW. Among the renewable energy sources are used wind and solar energy. For photovoltaic panels, we are considering two situations: fixed panels, oriented at 45° and panels with tracking system with two axis. Simulation results contain information regarding operation hours of the system throughout the year, energy produced from the renewable energy sources, energy consumption for the load, and excess of electrical energy. The Homer software also allows an economic analysis of these systems.

  18. SIMULATION OF THE SYSTEMS WITH RENEWABLE ENERGY SOURCES USING HOMER SOFTWARE

    Directory of Open Access Journals (Sweden)

    FIRINCĂ S.D.

    2015-12-01

    Full Text Available This paper simulates by using the Homer software, distributed energy systems with capacity below 1 MW. Among the renewable energy sources are used wind and solar energy. For photovoltaic panels, we are considering two situations: fixed panels, oriented at 45 ° and panels with tracking system with two axis. Simulation results contain information regarding operation hours of the system throughout the year, energy produced from the renewable energy sources, energy consumption for the load, and excess of electrical energy. The Homer software also allows an economic analysis of these systems.

  19. Dual arm robotic system with sensory input

    Science.gov (United States)

    Ozguner, U.

    1987-01-01

    The need for dual arm robots in space station assembly and satellite maintainance is of increasing significance. Such robots will be in greater demand in the future when numerous tasks will be assigned to them to relieve the direct intervention of humans in space. Technological demands from these robots will be high. They will be expected to perform high speed tasks with a certain degree of autonomy. Various levels of sensing will have to be used in a sophisticated control scheme. Ongoing research in control, sensing and real-time software to produce a two-arm robotic system than can accomplish generic assembly tasks is discussed. The control hierarchy and the specific control approach are discussed. A decentralized implementation of model-reference adaptive control using Variable Structure controllers and the incorporation of tactile feedback is considered.

  20. Designing a sustainable energy system for future slagelse city heat supply using energy planner web application

    OpenAIRE

    BoorBOOr, Marjan

    2013-01-01

    Currently, many activities and efforts are taking placed in different municipalities in Denmark in order to contribute to the national target,to phase out fossil fuel in the heat supply by 2030 and in the entire energy system in Denmark by 2050. However energy transition is a complex process and involved many section and include many inter relations. Any form of changes in one part can effects others which is one the biggest challege in energy transition and including these effects require...

  1. Influence of carbon electrode material on energy recovery from winery wastewater using a dual-chamber microbial fuel cell.

    Science.gov (United States)

    Penteado, Eduardo D; Fernandez-Marchante, Carmen M; Zaiat, Marcelo; Gonzalez, Ernesto R; Rodrigo, Manuel A

    2017-06-01

    The aim of this work was to evaluate three carbon materials as anodes in microbial fuel cells (MFCs), clarifying their influence on the generation of electricity and on the treatability of winery wastewater, a highly organic-loaded waste. The electrode materials tested were carbon felt, carbon cloth and carbon paper and they were used at the same time as anode and cathode in the tests. The MFC equipped with carbon felt reached the highest voltage and power (72 mV and 420 mW m(-2), respectively), while the lowest values were observed when carbon paper was used as electrode (0.2 mV and 8.37·10(-6) mW m(-2), respectively). Chemical oxygen demand (COD) removal from the wastewater was observed to depend on the electrode material, as well. When carbon felt was used, the MFC showed the highest average organic matter consumption rate (650 mg COD L(-1) d(-1)), whereas by using carbon paper the rate decreased to 270 mg COD L(-1) d(-1). Therefore, both electricity generation and organic matter removal are strongly related not to the chemical composition of the electrode (which was graphite carbon in the three electrodes), but to its surface features and, consequently, to the amount of biomass adhered to the electrode surface.

  2. Load frequency stabilization of four area hydro thermal system using Superconducting Magnetic Energy Storage system

    Directory of Open Access Journals (Sweden)

    A.Ruby meena

    2014-07-01

    Full Text Available Automatic generation control in electric power system design is a major concern nowadays due to its rising size, varying structure, integration of renewable-energy sources and distributed generators to meet the growing demand. In this paper, automatic generation control of an interconnected four area hydro thermal system examined. Each area equipped with reheat turbine for thermal system and hydro turbine with electric governor for hydro system. Load frequency stabilization gained by including Superconducting Magnetic Energy Storage system (SMES in all areas. A comparative analysis made between Proportional and Integral (PI controller with Fuzzy Logic controller with and without including SMES in the four area power system. The designed Fuzzy Logic Controller can generate best dynamic performance for step load perturbations given in all areas. The system simulation realized by using MATLAB software.

  3. Use of dual-energy X-ray absorptiometry (DXA) for diagnosis and fracture risk assessment; WHO-criteria, T- and Z-score, and reference databases.

    Science.gov (United States)

    Dimai, Hans P

    2017-11-01

    Dual-energy X-ray absorptiometry (DXA) is a two-dimensional imaging technology developed to assess bone mineral density (BMD) of the entire human skeleton and also specifically of skeletal sites known to be most vulnerable to fracture. In order to simplify interpretation of BMD measurement results and allow comparability among different DXA-devices, the T-score concept was introduced. This concept involves an individual's BMD which is then compared with the mean value of a young healthy reference population, with the difference expressed as a standard deviation (SD). Since the early nineties of the past century, the diagnostic categories "normal, osteopenia, and osteoporosis", as recommended by a WHO working Group, are based on this concept. Thus, DXA is still the globally accepted "gold-standard" method for the noninvasive diagnosis of osteoporosis. Another score obtained from DXA measurement, termed Z-score, describes the number of SDs by which the BMD in an individual differs from the mean value expected for age and sex. Although not intended for diagnosis of osteoporosis in adults, it nevertheless provides information about an individual's fracture risk compared to peers. DXA measurement can either be used as a "stand-alone" means in the assessment of an individual's fracture risk, or incorporated into one of the available fracture risk assessment tools such as FRAX® or Garvan, thus improving the predictive power of such tools. The issue which reference databases should be used by DXA-device manufacturers for T-score reference standards has been recently addressed by an expert group, who recommended use National Health and Nutrition Examination Survey III (NHANES III) databases for the hip reference standard but own databases for the lumbar spine. Furthermore, in men it is recommended use female reference databases for calculation of the T-score and use male reference databases for calculation of Z-score. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Repeatability of Volume and Regional Body Composition Measurements of the Lower Limb Using Dual-energy X-ray Absorptiometry

    DEFF Research Database (Denmark)

    Gjorup, Caroline A; Zerahn, Bo; Juul, Sarah

    2016-01-01

    Lower limb lymphedema is a dynamic condition in which tissue composition and volume measurements are affected. Various definitions of lower limb lymphedema exist but volume differences between the limbs are widely used. It is therefore necessary to have a readily available noninvasive measurement...... of agreement on the Bland-Altman plots. These results confirm DXA to be a highly repeatable method for volume and tissue composition measurements of the lower limb. In a population at risk of lymphedema, DXA offers a clinically readily available noninvasive method allowing multiple measurements of volume...... and tissue composition on a routine basis, important for diagnosing, monitoring, managing, and researching lymphedema....

  5. Implementation of dual-energy technique for virtual monochromatic and linearly mixed CBCTs

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Giles, William; Ren Lei; Bowsher, James; Yin Fangfang [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2012-10-15

    Purpose: To implement dual-energy imaging technique for virtual monochromatic (VM) and linearly mixed (LM) cone beam CTs (CBCTs) and to demonstrate their potential applications in metal artifact reduction and contrast enhancement in image-guided radiation therapy (IGRT). Methods: A bench-top CBCT system was used to acquire 80 kVp and 150 kVp projections, with an additional 0.8 mm tin filtration. To implement the VM technique, these projections were first decomposed into acrylic and aluminum basis material projections to synthesize VM projections, which were then used to reconstruct VM CBCTs. The effect of VM CBCT on the metal artifact reduction was evaluated with an in-house titanium-BB phantom. The optimal VM energy to maximize contrast-to-noise ratio (CNR) for iodine contrast and minimize beam hardening in VM CBCT was determined using a water phantom containing two iodine concentrations. The LM technique was implemented by linearly combining the low-energy (80 kVp) and high-energy (150 kVp) CBCTs. The dose partitioning between low-energy and high-energy CBCTs was varied (20%, 40%, 60%, and 80% for low-energy) while keeping total dose approximately equal to single-energy CBCTs, measured using an ion chamber. Noise levels and CNRs for four tissue types were investigated for dual-energy LM CBCTs in comparison with single-energy CBCTs at 80, 100, 125, and 150 kVp. Results: The VM technique showed substantial reduction of metal artifacts at 100 keV with a 40% reduction in the background standard deviation compared to a 125 kVp single-energy scan of equal dose. The VM energy to maximize CNR for both iodine concentrations and minimize beam hardening in the metal-free object was 50 keV and 60 keV, respectively. The difference of average noise levels measured in the phantom background was 1.2% between dual-energy LM CBCTs and equivalent-dose single-energy CBCTs. CNR values in the LM CBCTs of any dose partitioning are better than those of 150 kVp single-energy CBCTs. The

  6. Anthropometric variables accurately predict dual energy x-ray absorptiometric-derived body composition and can be used to screen for diabetes.

    Directory of Open Access Journals (Sweden)

    Reza Yavari

    Full Text Available The current world-wide epidemic of obesity has stimulated interest in developing simple screening methods to identify individuals with undiagnosed diabetes mellitus type 2 (DM2 or metabolic syndrome (MS. Prior work utilizing body composition obtained by sophisticated technology has shown that the ratio of abdominal fat to total fat is a good predictor for DM2 or MS. The goals of this study were to determine how well simple anthropometric variables predict the fat mass distribution as determined by dual energy x-ray absorptometry (DXA, and whether these are useful to screen for DM2 or MS within a population. To accomplish this, the body composition of 341 females spanning a wide range of body mass indices and with a 23% prevalence of DM2 and MS was determined using DXA. Stepwise linear regression models incorporating age, weight, height, waistline, and hipline predicted DXA body composition (i.e., fat mass, trunk fat, fat free mass, and total mass with good accuracy. Using body composition as independent variables, nominal logistic regression was then performed to estimate the probability of DM2. The results show good discrimination with the receiver operating characteristic (ROC having an area under the curve (AUC of 0.78. The anthropometrically-derived body composition equations derived from the full DXA study group were then applied to a group of 1153 female patients selected from a general endocrinology practice. Similar to the smaller study group, the ROC from logistical regression using body composition had an AUC of 0.81 for the detection of DM2. These results are superior to screening based on questionnaires and compare favorably with published data derived from invasive testing, e.g., hemoglobin A1c. This anthropometric approach offers promise for the development of simple, inexpensive, non-invasive screening to identify individuals with metabolic dysfunction within large populations.

  7. Dual use of tobacco among Bangladeshi men

    Directory of Open Access Journals (Sweden)

    M M Zaman

    2014-01-01

    Full Text Available Introduction: Dual use of tobacco (using smoking and smokeless forms in Bangladesh is uncommon in women but common in men. Dual users are at additional risk of cancers and heart diseases compared with a single form of tobacco use. Knowledge about their socioeconomic background is necessary for planning appropriate interventions. We report here socioeconomic background of the dual users of tobacco from a nationally representative survey. Methods: The study adopted a probability proportionate to size sampling technic of divisional population stratified into urban and rural areas to recruit men aged 25 years or older from their households. A total of 4312 men were recruited. Variables included questions on 20 household assets, tobacco use and other behavioral risk factors, and measurement of body weight and height. Results: The average age of dual users was 46.7 years old compared to 43.4 and 52.3 years for smokers and smokeless tobacco users. Prevalence of "smoking only," "smokeless only" and "dual use" of tobacco was 40.6%, 15.2%, and 14.2%, respectively. Among all tobacco users, dual users constituted 20%. These dual users had lower educational achievement, rural residence, lower intake of fruit, and higher intake of alcohol. They were more undernourished as indicated by a thin body mass index compared to nonusers and smokers. Dual users were of socioeconomically deprived as measured by wealth quartiles constructed out of household assets. Conclusion: Dual use of tobacco is common in Bangladesh, and it is intimately linked with socioeconomic deprivation. Poverty reduction strategy and campaigns should address tobacco control not only tobacco in general, but its dual use in particular.

  8. Primary energy savings using heat storage for biomass heating systems

    Directory of Open Access Journals (Sweden)

    Mitrović Dejan M.

    2012-01-01

    Full Text Available District heating is an efficient way to provide heat to residential, tertiary and industrial users. The heat storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the heat storage unit makes it possible to heat even when the boiler is not working, thus increasing the heating efficiency. In order to save primary energy (fuel, the boiler operates on nominal load every time it is in operation (for the purpose of this research. The aim of this paper is to analyze the water temperature variation in the heat storage, depending on the heat load and the heat storage volume. Heat load is calculated for three reference days, with average daily temperatures from -5 to 5°C. The primary energy savings are also calculated for those days in the case of using heat storage in district heating.[Projekat Ministarstva nauke Republike Srbije, br. TR 33051: The concept of sustainable energy supply of settlements with energy efficient buildings

  9. A New Fractal-Based Miniaturized Dual Band Patch Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Sika Shrestha

    2014-01-01

    Full Text Available The growth of wireless communications in recent years has made it necessary to develop compact, lightweight multiband antennas. Compact antennas can achieve the same performance as large antennas do with low price and with greater system integration. Dual-frequency microstrip antennas for transmission and reception represent promising approach for doubling the system capacity. In this work, a miniaturized dual band antenna operable at 2.45 and 5.8 GHz is constructed by modifying the standard microstrip patch antenna geometry into a fractal structure. In addition to miniaturization and dual band nature, the proposed antenna also removes unwanted harmonics without the use of additional filter component. Using a finite-element-method-based high frequency structure simulator (HFSS, the antenna is designed and its performance in terms of return loss, impedance matching, radiation pattern, and voltage standing wave ratio (VSWR is demonstrated. Simulation results are shown to be in close agreement with performance measurements from an actual antenna fabricated on an FR4 substrate. The proposed antenna can be integrated with a rectifier circuit to develop a compact rectenna that can harvest RF energy in both of these frequency bands at a reduction in size of 25.98% relative to a conventional rectangular patch antenna.

  10. USING TIME VARIANT VOLTAGE TO CALCULATE ENERGY CONSUMPTION AND POWER USE OF BUILDING SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Makhmalbaf, Atefe; Augenbroe , Godfried

    2015-12-09

    Buildings are the main consumers of electricity across the world. However, in the research and studies related to building performance assessment, the focus has been on evaluating the energy efficiency of buildings whereas the instantaneous power efficiency has been overlooked as an important aspect of total energy consumption. As a result, we never developed adequate models that capture both thermal and electrical characteristics (e.g., voltage) of building systems to assess the impact of variations in the power system and emerging technologies of the smart grid on buildings energy and power performance and vice versa. This paper argues that the power performance of buildings as a function of electrical parameters should be evaluated in addition to systems’ mechanical and thermal behavior. The main advantage of capturing electrical behavior of building load is to better understand instantaneous power consumption and more importantly to control it. Voltage is one of the electrical parameters that can be used to describe load. Hence, voltage dependent power models are constructed in this work and they are coupled with existing thermal energy models. Lack of models that describe electrical behavior of systems also adds to the uncertainty of energy consumption calculations carried out in building energy simulation tools such as EnergyPlus, a common building energy modeling and simulation tool. To integrate voltage-dependent power models with thermal models, the thermal cycle (operation mode) of each system was fed into the voltage-based electrical model. Energy consumption of systems used in this study were simulated using EnergyPlus. Simulated results were then compared with estimated and measured power data. The mean square error (MSE) between simulated, estimated, and measured values were calculated. Results indicate that estimated power has lower MSE when compared with measured data than simulated results. Results discussed in this paper will illustrate the

  11. Different energy management strategies of Hybrid Energy Storage System (HESS) using batteries and supercapacitors for vehicular applications

    OpenAIRE

    ALLEGRE, Anne-Laure; Trigui, Rochdi; Bouscayrol, Alain

    2010-01-01

    The energy storage is a key issue for traction applications like Electric Vehicles (EVs) or Hybrid Electric Vehicles (HEVs). Indeed, it needs a higher power and energy density, a right size, a long lifetime and a low cost. A Hybrid Energy Storage System (HESS) using batteries and supercapacitors seems to be an appropriate device to fulfill these constraints. The objective of the paper is to propose different energy management strategies of HESS using batteries and supercapacitors. Four elabor...

  12. Different energy management strategies of Hybrid Energy Storage System (HESS) using batteries and supercapacitors for vehicular applications

    OpenAIRE

    ALLEGRE, Anne-Laure; TRIGUI, Rochdi; Bouscayrol, Alain

    2010-01-01

    The energy storage is a key issue for traction applications like Electric Vehicles (EVs) or Hybrid Electric Vehicles (HEVs). Indeed, it needs a higher power and energy density, a right size, a long lifetime and a low cost. A Hybrid Energy Storage System (HESS) using batteries and supercapacitors seems to be an appropriate device to fulfill these constraints. The objective of the paper is to propose different energy management strategies of HESS using batteries and supercapacitors. Four elabor...

  13. Actuator System with Dual Chambers

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to an actuator system with a magnetic lead screw (50), comprises a magnetic rotor (5) and a translator cylinder (2), the translator cylinder (2) comprises a magnetic stator (16), the translator cylinder (2) has a closed first end (14) and a second end confined by a lid...... (8), the lid having a shaft opening (17) for a shaft (6) coupled to the magnetic rotor (5), wherein the magnetic rotor (5), when inserted in the translator cylinder (2), is arranged to translate a linear movement of the translator cylinder (2) into a rotational movement of the magnetic rotor by using...... movement in the shaft opening (17), the lid (8) being arranged for confining the second end (15) of the translator cylinder (2), the translator cylinder confined by the lid (8) forms,when divided by the magnetic rotor (5), a first chamber (TC) with a first volume and a second chamber(BC) with a second...

  14. Evaluation of a dichromatic X-ray source for dual-energy imaging in mammography

    Science.gov (United States)

    Tuffanelli, A.; Fabbri, S.; Sarnelli, A.; Taibi, A.; Gambaccini, M.

    2002-08-01

    A novel X-ray system, providing dichromatic beams for dual-energy radiography, has been assembled. The source generates pairs of superimposed quasi-monochromatic beams, having energies E and 2 E, with E tuneable in the 15-20 keV range. In this paper the characteristics of the radiation field in terms of energy resolution and fluence, for three dichromatic X-ray beams are reported. A study of the spectra attenuated by a 5 cm-thick phantom of breast equivalent tissue demonstrates that the optimal energy of the dichromatic beam for dual-energy application may be set as a function of the thickness of investigated tissue. A detailed topographic study of mean energy and flux shows the spatial superposition of the first and the second diffraction order beam, that is the main requirement for the application of a single exposure dual-energy radiography. The bidimensional mapping of the irradiated beam is also reported, showing the presence of energy and intensity gradients. We estimate that the observed gradients do not affect the results of dual-energy technique application in an appreciable way.

  15. 14 CFR 23.399 - Dual control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Dual control system. 23.399 Section 23.399... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Control Surface and System Loads § 23.399 Dual control system. (a) Each dual control system must be designed to withstand the...

  16. 14 CFR 25.399 - Dual control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Dual control system. 25.399 Section 25.399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.399 Dual control system. (a) Each dual control system must be designed for the pilots operating in opposition,...

  17. 14 CFR 29.399 - Dual control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Dual control system. 29.399 Section 29.399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Control Surface and System Loads § 29.399 Dual control system. Each dual primary flight control system must be able to withstand the loads that...

  18. 14 CFR 27.399 - Dual control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Dual control system. 27.399 Section 27.399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Control Surface and System Loads § 27.399 Dual control system. Each dual primary flight control system must be designed to withstand the loads that...

  19. The Empirical Study on Chinese Style Dual System Basing on Foxconn Training Base Program

    Institute of Scientific and Technical Information of China (English)

    Guo Nan

    2012-01-01

      So far many existing papers have made study on dual system.While most scholars take the opinion that dual system can give obviously positive effect to skilled talent training, some theorists argue that the precondition of dual system performs excellently is dual system should be localized according to the reality of a country or a district.This paper analyzes dual system practice in China from an example of Foxconn Training Base,the conclusion is that in Foxconn Training Base Program,dual system has been localized successfully and evolved into trian-gle system,and this program management pattern can be used in other areas of China as a mature,standard Chinese dual system pattern for skil ed talent training.

  20. 6. Kassel symposium on energy system engineering. On-site energy generation using renewable energy sources. Proceedings 2001; 6. Kasseler Symposium: Energie-Systemtechnik. Erneuerbare Energien und rationelle Energieverwendung. Innovative Energiewandler. Tagungsband 2001

    Energy Technology Data Exchange (ETDEWEB)

    Caselitz, P. (comp.)

    2001-07-01

    The sixth Kassel symposium on energy system engineering. On-site energy generation using renewable energy sources focuses on the subject of innovative energy converter. The status and the development of generally known technologies is not only supposed to be reported on but also some conversion methods, which are currently not too well known. The changed frame conditions in the field of energy economy cause some systems, which have already been developed, to appear in a new light. The first talk of this symposium does not really discuss a method of energy conversion compared to the other talks. It rather describes a scenario that focuses on silicium as future energy carrier. Further contributions report on new, innovative concepts for electrical partial systems of wind and water power plants with variable revolution. Modern design methods for water turbines are presented with the example of hydraulic turbo-engines. Three contributions present the current status of technology and perspectives in the field of photovoltaics, thermal photovoltaics as well as new developments in the field of solarthermal systems. Talks about micro gas turbines and fuel cells discuss the use of these systems in dual purpose power plants and in the field of energy supply for houses. Information about modern steam engines and the use of Stirling engines in the field of biomass utilization complete the subject range of this symposium. (orig.) [German] Das 6. Kasseler Symposium zur Nutzung erneuerbarer Energien und rationellen Energieverwendung widmet sich dem Thema Innovative Energiewandler. Dabei soll nicht nur ueber den Stand und die Entwicklung weithin bekannter Technologien berichtet werden. Vorgestellt werden auch einige Konversionsverfahren, deren Bekanntheitsgrad heute noch gering ist. Auch lassen die veraenderten Rahmenbedingungen in der Energiewirtschaft einige im Prinzip entwickelte Systeme moeglicherweise in einem neuen Licht erscheinen. Der erste Beitrag des Symposiums setzt

  1. Percentage of body fat assessment using bioelectrical impedance analysis and dual-energy X-ray absorptiometry in a weight loss program for obese or overweight Chinese adults.

    Directory of Open Access Journals (Sweden)

    Yi-Chun Li

    Full Text Available The current study aimed to compare the estimates of body fat percentage (%BF by performing bioelectrical impedance analysis (BIA and dual energy X-ray absorptiometry (DXA in a sample of obese or overweight Chinese adults who participated in a weight-loss randomized control trial stratified by gender to determine whether or not BIA is a valid measurement tool. Among 189 adults [73 males, 116 females; age = 41 to 74 years; mean body mass index (BMI = 27.3 kg/m(2], assessments of %BF at the baseline and six months from the baseline were conducted by performing BIA and DXA. Bland-Altman analyses and multiple regression analyses were used to assess the relationships between %BFBIA and %BFDXA. Compared with DXA, BIA underestimated %BF [in males: 4.6, -2.4 to 11.7 (mean biases, 95% limit of agreement at the baseline, 1.4, -7.4 to 10.2 at the endpoint, and 3.2, -4.8 to 11.3 in changes; in females: 5.1, -2.4 to 12.7; 2.2, -6.1 to 10.4; and 3.0, -4.8 to 10.7, respectively]. For males and females, %BFDXA proved to be a significant predictor of the difference between DXA and BIA at the baseline, the endpoint, and in changes when BMI and age were considered (in males: p<0.01 and R (2 = 23.1%, 24.1%, 20.7%, respectively; for females: p<0.001 and R (2 = 40.4%, 48.8%, 25.4%, respectively. The current study suggests that BIA provides a relatively accurate prediction of %BF in individuals with normal weight, overweight, or obesity after the end of weight-loss program, but less accurate prediction of %BF in obese individuals at baseline or weight change during the weight-loss intervention program.

  2. The use of energy management and control systems to monitor the energy performance of commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Heinemeier, K E [Univ. of California, Berkeley, CA (United States). Dept. of Architecture

    1994-12-01

    Monitored data play a very important part in the implementation and evaluation of energy conservation technologies and programs. However, these data can be expensive to collect, so there is a need for lower-cost alternatives. In many situations, using the computerized Energy Management and Control Systems (EMCSs)--already installed in many buildings--to collect these commercial building performance data has advantages over more conventional methods. This method provides data without installing incremental hardware, and the large amounts of available operational data can be a very rich resource for understanding building performance. This dissertation addresses several of these issues. One specific objective is to describe a monitoring-project planning process that includes definition of objectives, constraints, resources and approaches for the monitoring. The choice of tools is an important part of this process. The dissertation goes on to demonstrate, through eight case studies, that EMCS monitoring is possible, and to identify and categorize the problems and issues that can be encountered. These issues lead to the creation, use, and testing of a set of methods for evaluation of EMCS monitoring, in the form of guidelines. Finally, EMCS monitoring is demonstrated and compared with conventional monitoring more methodically in a detailed case study.

  3. Dual-energy contrast-enhanced breast tomosynthesis: optimization of beam quality for dose and image quality.

    Science.gov (United States)

    Samei, Ehsan; Saunders, Robert S

    2011-10-07

    Dual-energy contrast-enhanced breast tomosynthesis is a promising technique to obtain three-dimensional functional information from the breast with high resolution and speed. To optimize this new method, this study searched for the beam quality that maximized image quality in terms of mass detection performance. A digital tomosynthesis system was modeled using a fast ray-tracing algorithm, which created simulated projection images by tracking photons through a voxelized anatomical breast phantom containing iodinated lesions. The single-energy images were combined into dual-energy images through a weighted log subtraction process. The weighting factor was optimized to minimize anatomical noise, while the dose distribution was chosen to minimize quantum noise. The dual-energy images were analyzed for the signal difference to noise ratio (SdNR) of iodinated masses. The fast ray-tracing explored 523 776 dual-energy combinations to identify which yields optimum mass SdNR. The ray-tracing results were verified using a Monte Carlo model for a breast tomosynthesis system with a selenium-based flat-panel detector. The projection images from our voxelized breast phantom were obtained at a constant total glandular dose. The projections were combined using weighted log subtraction and reconstructed using commercial reconstruction software. The lesion SdNR was measured in the central reconstructed slice. The SdNR performance varied markedly across the kVp and filtration space. Ray-tracing results indicated that the mass SdNR was maximized with a high-energy tungsten beam at 49 kVp with 92.5 µm of copper filtration and a low-energy tungsten beam at 49 kVp with 95 µm of tin filtration. This result was consistent with Monte Carlo findings. This mammographic technique led to a mass SdNR of 0.92 ± 0.03 in the projections and 3.68 ± 0.19 in the reconstructed slices. These values were markedly higher than those for non-optimized techniques. Our findings indicate that dual-energy

  4. Multiphase Venturi Dual Energy Gamma Ray combination performance in NUEX flow loop; Desempenho no flowloop do NUEX da medicao multifasica Venturi Dual Energy Gamma Ray

    Energy Technology Data Exchange (ETDEWEB)

    Barreiros, Claudio; Taranto, Cleber; Costa, Alcemir [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Pinguet, Bruno; Heluey, Vitor; Bessa, Fabiano; Loicq, Olivier [Schlumberger Servicos de Petroleo Ltda., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The Multiphase Venturi Dual Energy Gamma Ray Combination, Vx* technology, arrived in Brazil in 2000. PETROBRAS, Brazilian Oil Company, has been putting big efforts in its production business and also has demonstrated a large interest in having a multiphase meter approved by ANP for back allocation purposes. The oil industry was looking for ways to improve the back allocation process using an approved on line multiphase flow measurement device, thus replacing punctual test done today by a permanent monitoring device. Considering this scenario, a partnership project between PETROBRAS and Schlumberger was created in Brazil. The main objective of this project, which was held in NUEX flow loop, was to demonstrate to INMETRO (Brazilian Metrology Institute) that the Multiphase Venturi Dual Energy Gamma Ray Combination meter is able to be used for back allocation purpose. PETROBRAS and Schlumberger elaborated a complete methodology in the NUEX flow loop to demonstrate the results and benefits of the Multiphase Venturi Dual Energy Gamma Ray Combination meter. The test was witnessed by INMETRO and had a very good performance at the end. The results were within what was expected by Schlumberger, PETROBRAS and INMETRO. These results has been very useful to PETROBRAS in order to start using the Venturi Dual Energy Gamma Ray technology for well allocation purposes. (author)

  5. A cooling system for buildings using wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Daiyan, H. [Islamic Azad Univ., Semnan Branch (Iran)

    2007-05-15

    In Iranian historical architecture wind towers are used for cooling and ventilation. A wind tower is a tall structure that stands on the building. A wind tower is used in dray land, and only uses wind energy for conditioning. Its technology dates back over 1000 years. Wind towers were designed according to several parameters, some of the most important of which were building type, cooling space volume, wind direction and velocity and ambient temperature. This paper studies wind towers and characterizes airflow route and explains how to decrease temperature. To confirm the quality of the wind tower, some experiments in a case study shows it can decrease room temperature on comfort range and room temperature is almost constant on during day. (au)

  6. Reactive Power Compensation Using an Energy Management System

    Science.gov (United States)

    2014-09-01

    compiled to VHDL code using Xilinx System Generator software [12], which is used by the FPGA to command the EMS. The FPGA development board is the middle...a straightforward process. Upon completing the lab setup, the Simulink simulation was compiled into VHDL code on a PC and uploaded to the FPGA...development board on the EMS using Xilinx software. The VHDL code enabled the EMS to execute the power factor correction methodology developed in

  7. Impact of dual energy characterization of urinary calculus on management.

    Science.gov (United States)

    Habashy, David; Xia, Ryan; Ridley, William; Chan, Lewis; Ridley, Lloyd

    2016-10-01

    Dual energy CT (DECT) is a recent technique that is increasingly being used to differentiate between calcium and uric acid urinary tract calculi. The aim of this study is to determine if urinary calculi composition analysis determined by DECT scanning results in a change of patient management. All patients presenting with symptoms of renal colic, who had not previously undergone DECT scanning underwent DECT KUB. DECT data of all patients between September 2013 and July 2015 were reviewed. Urinary calculi composition based on dual energy characterization was cross-matched with patient management and outcome. A total of 585 DECT KUB were performed. 393/585 (67%) DECT scans revealed urinary tract calculi. After excluding those with isolated bladder or small asymptomatic renal stones, 303 patients were found to have symptomatic stone(s) as an explanation for their presentation. Of these 303 patients, there were 273 (90.1%) calcium calculi, 19 (6.3%) uric acid calculi and 11 (3.4%) mixed calculi. Of those with uric acid calculi, 15 were commenced on dissolution therapy. Twelve of those commenced on dissolution therapy had a successful outcome, avoiding need for surgical intervention (lithotripsy or stone retrieval). Three patients failed dissolution therapy and required operative intervention for definitive management of the stone. Predicting urinary tract calculi composition by DECT plays an important role in identifying patients who may be managed with dissolution therapy. Identification of uric acid stone composition altered management in 15 of 303 (5.0%) patients, and was successful in 12, thereby avoiding surgery and its attendant risks. © 2016 The Royal Australian and New Zealand College of Radiologists.

  8. Cartilage imaging of a rabbit knee using dual-energy X-ray microscopy and 1.0 T and 9.4 T magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Ying Zhu

    2015-10-01

    Conclusion: Our results suggest that the dual-energy XRM for articular-cartilage analysis is feasible and comparable to the MRI. This technology will provide good support for high-resolution animal-osteoarthritis studies, and in the future, it may be possible to apply dual energy in a clinical setting.

  9. Experimental demonstration of a FBG-based temporal optical pulse shaping scheme dual to spatial arrangements for its use in OCDMA systems

    Science.gov (United States)

    Tainta, Santiago; Amaya, Waldimar; García, Raimundo; Erro, María J.; Garde, María J.; Sales, Salvador; Muriel, Miguel A.

    2009-11-01

    We have demonstrated a reconfigurable time domain spectral phase encoding scheme for coherent optical code-divisionmultiple- access application. The proposed scheme is based on the concept of temporal pulse shaping dual to spatial arrangements. It uses Fiber Bragg Gratings as dispersive elements and electro-optic modulators. The data speed is 1.25 Gbps and the code is introduced at 10 Gcps, using a subset of the Hadamard codes with a length of 8 chips within a 0.7 nm optical window. The system is electrically reconfigurable and compatible with fiber systems and permits scalability in the size of the codes by modifying only the phase modulator velocity.

  10. Quantum mechanics/molecular mechanics dual Hamiltonian free energy perturbation.

    Science.gov (United States)

    Polyak, Iakov; Benighaus, Tobias; Boulanger, Eliot; Thiel, Walter

    2013-08-14

    The dual Hamiltonian free energy perturbation (DH-FEP) method is designed for accurate and efficient evaluation of the free energy profile of chemical reactions in quantum mechanical/molecular mechanical (QM/MM) calculations. In contrast to existing QM/MM FEP variants, the QM region is not kept frozen during sampling, but all degrees of freedom except for the reaction coordinate are sampled. In the DH-FEP scheme, the sampling is done by semiempirical QM/MM molecular dynamics (MD), while the perturbation energy differences are evaluated from high-level QM/MM single-point calculations at regular intervals, skipping a pre-defined number of MD sampling steps. After validating our method using an analytic model potential with an exactly known solution, we report a QM/MM DH-FEP study of the enzymatic reaction catalyzed by chorismate mutase. We suggest guidelines for QM/MM DH-FEP calculations and default values for the required computational parameters. In the case of chorismate mutase, we apply the DH-FEP approach in combination with a single one-dimensional reaction coordinate and with a two-dimensional collective coordinate (two individual distances), with superior results for the latter choice.

  11. Revisiting impressions using dual-arch trays.

    Science.gov (United States)

    Small, Bruce W

    2012-01-01

    Making routine perfect impressions is the goal of any restorative dentist. Using dual-arch trays is an easy, repeatable way to accomplish that goal, as long as each step is done before the next and each step is performed perfectly. This column reviewed several articles that support the metal dual-arch concept and provided some clinical tips that might help restorative dentists. The dual-arch technique does have its limits and is meant for one or two teeth in a quadrant when there are other teeth to occlude with. Also, if the case involves anterior guidance, a full-arch impression maybe advisable.

  12. Fuel for Food: Energy Use in the U.S. Food System

    OpenAIRE

    Canning, Patrick N.

    2010-01-01

    In 2007, the U.S. food system accounted for almost 16 percent of the Nation’s energy budget. Between 1997 and 2002, over 80 percent of the increase in annual U.S. energy consumption was food related. Population growth, higher per capita food expenditures, and greater reliance on energy-using technologies boosted food-related energy consumption.

  13. The electrical storage systems in energy networks with fuel cells and photovoltaic systems for residential use

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Y.; Aki, H. [National Inst. of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan)

    2007-07-01

    Fuel cell systems and photovoltaic systems are expected to penetrate Japan's residential sector as a distributed energy resource. However, in order to connect photovoltaic systems to the electricity grid in Japan, the power conditioner of the photovoltaic system should have a function to restrict output. The purpose of this study was to establish a cooperative operations method for fuel cells, photovoltaic cells and electrical storage devices. In the proposed networks of this study, electricity, hydrogen and hot water were interchanged and the equipment was shared for cooperative operation. The power generated by the photovoltaic system fluctuated widely. The power flow at the connecting point of the energy networks to the electric power distribution system was bidirectional and depended on the balance of the power produced by the photovoltaic system as well as the power consumption. The use of an electrical storage system for the proposed networks ensured the stability of the power system and enabled more flexible operation of fuel cell stacks. The cooperative operational method for fuel cell systems, photovoltaic systems and electrical storage systems involved the combination of an electrical double layer capacitor (EDLC) and a lithium-ion battery for residential dwellings. Simulation results showed that the use of an EDLC reduced the required capacity of electrical storage systems and the fluctuation of output power of fuel cell systems. The construction of an experimental facilities is being planned to evaluate the charge-discharge characteristics of the electric storage devices and auxiliary equipment, such as inverters. 1 ref., 1 tab., 5 figs.

  14. Solar energy conversion systems

    CERN Document Server

    Brownson, Jeffrey R S

    2013-01-01

    Solar energy conversion requires a different mind-set from traditional energy engineering in order to assess distribution, scales of use, systems design, predictive economic models for fluctuating solar resources, and planning to address transient cycles and social adoption. Solar Energy Conversion Systems examines solar energy conversion as an integrative design process, applying systems thinking methods to a solid knowledge base for creators of solar energy systems. This approach permits different levels of access for the emerging broad audience of scientists, engineers, architects, planners

  15. Analysis of base isolation and energy dissipation systems for NPP structures using fragility models

    Energy Technology Data Exchange (ETDEWEB)

    Vulpe, A. [Technical Univ. of Iasi (Romania). Dept. of Structural Mechanics; Carausu, A. [Technical Univ. of Iasi (Romania). Dept. od Mathematics

    1995-12-31

    Some extensions of analytical models for base isolation and energy dissipation systems, involving fragility models, are presented. The equation of motion is extended with a term corresponding to Energy Dissipation effect, and the fragility of IEDS (Isolation and Energy Dissipations Systems) is evaluated using a bilinear regression line. (author). 11 refs., 2 figs.

  16. Numerical study of a water distillation system using solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Zarzoum, K.; Zhani, K. [Sfax University, (Turkey); Bacha, H. Ben [Prince Sattam Bin Abdulaziz University, Alkharj (Saudi Arabia)

    2016-02-15

    This paper tackles an optimization approach in order to boost the fresh water production of a new design of a solar still which is located at Sfax engineering national school in Tunisia. This optimization approach is based upon the above mentioned design's improvement by coupling the conventional solar still into at a condenser, solar air and water collector and humidifier. This new concept of a distiller solar still using humidification- dehumidification processes (HD) is exploited for the desalination purpose. As a result of this work, the humidification- dehumidification processes have an essential effect in improving the solar still performance. Performance has been predicted theoretically in terms of water and inner glass cover temperatures, the inlet temperature of air and water of the new concept of distiller on water condensation rate and fresh water production. A general model based on heat and mass transfers in each component of the unit has been developed in steady dynamic regime. The developed model is used, simulating the HD system, to investigate the influence of the meteorological and operating parameters on the system productivity. The obtained set of ordinary differential equations has been converted to a set of algebraic system of equations by the functional approximation method of orthogonal collocation. The developed model is used to simulate the HD system in order to investigate the steady state behavior of each component of the unit and the entire system exposed to a variation of the entrance parameters and meteorological conditions. The obtained results were compared with those of other studies and the comparison gives a good validity of the present results.

  17. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    Science.gov (United States)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-03-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56-0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose.

  18. Evaluación energética de un sistema de generación de 400 kWe en modo diesel‐gas licuado de petróleo//Energy analysis of a 400 kWe power system operated on dual fuel mode with diesel‐liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    Carlos‐A. Forero-Núñez

    2014-08-01

    Full Text Available El constante aumento en los precios de los combustibles impulsó el desarrollo de sistemas energéticos cada vez más eficientes y flexibles, los cuales permitan el uso de distintos tipos de combustibles, tales como el gas licuado de petróleo (GLP. El presente trabajo buscó analizar el comportamiento energético y ambiental que tiene una planta de generación de 400 kWe operada en modo diesel y dual diesel-GLP de pozo. La eficiencia energética total del sistema en el punto de máxima carga fue igual a 39,9 % en modo diesel y 35,1 % con una relación de sustitución del 28,5 % en modo dual. La adición de GLP resultó en una disminución del índice de emisiones de CO2 de 0,76 a 0,71 kgkWh-1. El adecuado comportamiento del sistema genera interesantes oportunidades para la disminución del impacto ambiental causado por los sistemas diesel, la diversificación de la canasta energética y la reducción de costos de generación eléctrica en pozos petroleros.Palabras claves: eficiencia energética, diesel, GLP, modo dual.________________________________________________________________________________AbstractThe continuous increase of the fuel costs promoted the development of more efficient and flexible power systems, which could use alternative fuels such as liquefied petroleum gas (LPG. This work aimed to analyze the performance and environmental effect of a 400kWe power system fed with diesel and diesel-LGP on a dual fuel mode. The total electric efficiency of this system at his maximum load was 39,9 % with diesel and 35,1 % at a 28,5 % substitution level on a dual fuel mode. The addition of LPG decreased the CO2 emission index from 0,76 to 0,71 kgkWh-1. The proper behavior of this system on a dual fuel mode mitigated the environmental impact of diesel internal combustion engines, diversified the energy market, and reduced the power generation costs onto petroleum extraction wells.Key words: energy efficiency, diesel, LPG, dual fuel mode.

  19. 双轴伺服太阳能跟踪器控制系统设计%Design of Dual-Axis Servo Solar Energy Tracker Control System

    Institute of Scientific and Technical Information of China (English)

    郑春娇; 石玉峰

    2013-01-01

    This paper designed a dual-axis servo solar tracker based on single chip micyoco (SCM). The whole system consisted of minimum system of SCM, position detection circuit, irradiance comparison circuit, clock circuit, keyboard circuit, motor speed regu-lation circuit and angular position sensor. The software included the calculation of solar altitude and azimuth angle, the main program and each functional module subprograms. The results from debugging and running show that the system is stable, precisely tracking the sun in real time.%设计了基于单片机的双轴伺服太阳能跟踪器。整个系统由单片机最小系统、四路方位检测电路、辐照度比较电路、时钟电路、键盘电路、电机调速电路和角度传感器等组成,软件部分包括太阳高度角和方位角计算、主程序及各个功能模块子程序。经实物模型调试运行结果表明,系统工作稳定、实时性好,能够正确完成对太阳的跟踪。

  20. Renewable Energy Systems

    DEFF Research Database (Denmark)

    Lund, Henrik

    2014-01-01

    are to be found when the electricity sector is combined with the heating and cooling sectors and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. The paper illustrates why electricity smart......This paper presents the learning of a series of studies that analyse the problems and perspectives of converting the present energy system into a 100 % renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus...... on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies. The typical smart grid sole focus on the electricity sector often leads to the conclusion that transmission lines, flexible electricity...

  1. Renewable Energy Systems

    DEFF Research Database (Denmark)

    Lund, Henrik; Mathiesen, Brian Vad; Connolly, David

    2014-01-01

    This paper presents the learning of a series of studies that analyse the problems and perspectives of converting the present energy system into a 100 % renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus...... on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies. The typical smart grid sole focus on the electricity sector often leads to the conclusion that transmission lines, flexible electricity...... are to be found when the electricity sector is combined with the heating and cooling sectors and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. The paper illustrates why electricity smart...

  2. EXAMINING A SERIES RESONANT INVERTER CIRCUIT TO USE IN THE PHOTOVOLTAIC ENERGY CONVERSION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Engin ÇETİN

    2004-03-01

    Full Text Available As we know, solar energy is the energy source which is environment friendly, renewable, and can be found easily. Particularly, in the recent years, interest on producing electrical energy by alternative energy sources increased because of the fact that underground sources are not enough to produce energy in the future and also these sources cause enviromental pollution. The solar energy is one of the most popular one among the alternative energy sources. Photovoltaic systems produce the electrical energy from the sunlight. In this study, a series resonant inverter circuit which is used in the photovoltaic energy conversion systems has been examined.Effects of the series resonant inverter circuit on the photovoltaic energy conversion system have been investigated and examined

  3. A magnetic-spring-based, low-frequency-vibration energy harvester comprising a dual Halbach array

    Science.gov (United States)

    Salauddin, M.; Halim, M. A.; Park, J. Y.

    2016-09-01

    Energy harvesting that uses low-frequency vibrations is attractive due to the availability of such vibrations throughout the ambient environment. Significant power generation at low-frequency vibrations, however, is challenging because the power flow decreases as the frequency decreases; moreover, designing a spring-mass system that is suitable for low-frequency-vibration energy harvesting is difficult. In this work, our proposed device overcomes both of these challenges by using a dual Halbach array and magnetic springs. Each Halbach array concentrates the magnetic-flux lines on one side of the array while suppressing the flux lines on the other side; therefore, a dual Halbach array allows for an interaction between the concentrated magnetic-flux lines and the same coil so that the maximum flux linkage occurs. During the experiment, vibration was applied in a horizontal direction to reduce the gravity effect on the Halbach-array structure. To achieve an increased power generation at low-amplitude and low-frequency vibrations, the magnetic structure of the dual Halbach array and the magnetic springs were optimized in terms of the operating frequency and the power density; subsequently, a prototype was fabricated and tested. The prototype device offers a normalized power density of 133.45 μW cm-3 g-2 that is much higher than those of recently reported electromagnetic energy harvesters; furthermore, it is capable of delivering a maximum average power of 1093 μW to a 44 Ω optimum load, at an 11 Hz resonant frequency and under a 0.5 g acceleration.

  4. Correlation between Dual-Energy and Perfusion CT in Patients with Hepatocellular Carcinoma.

    Science.gov (United States)

    Gordic, Sonja; Puippe, Gilbert D; Krauss, Bernhard; Klotz, Ernst; Desbiolles, Lotus; Lesurtel, Mickaël; Müllhaupt, Beat; Pfammatter, Thomas; Alkadhi, Hatem

    2016-07-01

    Purpose To develop a dual-energy contrast media-enhanced computed tomographic (CT) protocol by using time-attenuation curves from previously acquired perfusion CT data and to evaluate prospectively the relationship between iodine enhancement metrics at dual-energy CT and perfusion CT parameters in patients with hepatocellular carcinoma (HCC). Materials and Methods Institutional review board and local ethics committee approval and written informed consent were obtained. The retrospective part of this study included the development of a dual-energy CT contrast-enhanced protocol to evaluate peak arterial enhancement of HCC in the liver on the basis of time-attenuation curves from previously acquired perfusion CT data in 20 patients. The prospective part of the study consisted of an intraindividual comparison of dual-energy CT and perfusion CT data in another 20 consecutive patients with HCC. Iodine density and iodine ratio (iodine attenuation of the lesion divided by iodine attenuation in the aorta) from dual-energy CT and arterial perfusion (AP), portal venous perfusion, and total perfusion (TP) from perfusion CT were compared. Pearson R and linear correlation coefficients were calculated for AP and iodine density, AP and iodine ratio, TP and iodine density, and TP and iodine ratio. Results The dual-energy CT protocol consisted of bolus tracking in the abdominal aorta (threshold, 150 HU; scan delay, 9 seconds). The strongest intraindividual correlations in HCCs were found between iodine density and AP (r = 0.75, P = .0001). Moderate correlations were found between iodine ratio and AP (r = 0.50, P = .023) and between iodine density and TP (r = 0.56, P = .011). No further significant correlations were found. The volume CT dose index (11.4 mGy) and dose-length product (228.0 mGy · cm) of dual-energy CT was lower than those of the arterial phase of perfusion CT (36.1 mGy and 682.3 mGy · cm, respectively). Conclusion A contrast-enhanced dual-energy CT protocol developed

  5. Optimal control of oscillation wave energy system using velocity premonition

    Institute of Scientific and Technical Information of China (English)

    CUI; Xiao

    2015-01-01

    Recently ocean wave energy draw much more attention for its widespread,abundant and highly energy flux density properties.Extracting energy from incident wave however,is limited for the random and unstable power input.Motion control for WEC is a promising method to improve the energy absorption and some practical applications are also verified such as latching control.In this paper,an active control strategy is proposed to achieve maximum energy capture.The mathematical description shows that the active control has the characteristic of anti-causal and the wave premonition is necessary for controller design.But the fact of premonition time horizon is still unclear.In this paper,the premonition nature is described mathematically based on hydrodynamic theory.Furthermore,a simulation is also performed to study the impacting of premonition time horizon on WEC’s properties and give a more insightful understanding of WEC active control.

  6. Evaluating the ability of current energy use assessment methods to study contrasting livestock production systems.

    Science.gov (United States)

    Vigne, Mathieu; Vayssières, Jonathan; Lecomte, Philippe; Peyraud, Jean-Louis

    2012-12-15

    Environmental impact assessment of agriculture has received increased attention over recent decades, leading to development of numerous methods. Among them, three deal with energy use: Energy Analysis (EA), Ecological Footprint (EF) and Emergy synthesis (Em). Based on a review of 197 references applying them to a variety of agricultural systems, this paper evaluates their ability to assess energy use. While EF assesses energy use as land use via a global accounting approach in which energy is only one component of the assessment, EA and Em are energy-focused and appear more appropriate to highlight ways to increase energy-use efficiency. EA presents a clear methodology via fossil energy use and its associated impacts but does not consider all energy sources. With inclusion of natural and renewable resources, Em focuses on other energy resources, such as solar radiation and energy from labour, but does not present impact indicators nor establish a clear link between activities and their environmental impacts. Improvements of the EA and Em methods could increase their ability to perform realistic and unbiased energy analysis or the diversity of livestock systems encountered in the world. First, to consider all energy sources, as Em does, EA could include solar radiation received by farm surfaces and energy expenditure by humans and animals to accomplish farm operations. Second, boundaries of the studied system in EA and Em must include draft animals, humans and communal grazing lands. Third, special attention should be given to update and locally adapt energy coefficients and transformities.

  7. Improvement of material decomposition and image quality in dual-energy radiography by reducing image noise

    Science.gov (United States)

    Lee, D.; Kim, Y.-s.; Choi, S.; Lee, H.; Choi, S.; Jo, B. D.; Jeon, P.-H.; Kim, H.; Kim, D.; Kim, H.; Kim, H.-J.

    2016-08-01

    Although digital radiography has been widely used for screening human anatomical structures in clinical situations, it has several limitations due to anatomical overlapping. To resolve this problem, dual-energy imaging techniques, which provide a method for decomposing overlying anatomical structures, have been suggested as alternative imaging techniques. Previous studies have reported several dual-energy techniques, each resulting in different image qualities. In this study, we compared three dual-energy techniques: simple log subtraction (SLS), simple smoothing of a high-energy image (SSH), and anti-correlated noise reduction (ACNR) with respect to material thickness quantification and image quality. To evaluate dual-energy radiography, we conducted Monte Carlo simulation and experimental phantom studies. The Geant 4 Application for Tomographic Emission (GATE) v 6.0 and tungsten anode spectral model using interpolation polynomials (TASMIP) codes were used for simulation studies and digital radiography, and human chest phantoms were used for experimental studies. The results of the simulation study showed improved image contrast-to-noise ratio (CNR) and coefficient of variation (COV) values and bone thickness estimation accuracy by applying the ACNR and SSH methods. Furthermore, the chest phantom images showed better image quality with the SSH and ACNR methods compared to the SLS method. In particular, the bone texture characteristics were well-described by applying the SSH and ACNR methods. In conclusion, the SSH and ACNR methods improved the accuracy of material quantification and image quality in dual-energy radiography compared to SLS. Our results can contribute to better diagnostic capabilities of dual-energy images and accurate material quantification in various clinical situations.

  8. Dual-Modality Imaging of the Human Finger Joint Systems by Using Combined Multispectral Photoacoustic Computed Tomography and Ultrasound Computed Tomography

    Science.gov (United States)

    Liu, Yubin; Wang, Yating

    2016-01-01

    We developed a homemade dual-modality imaging system that combines multispectral photoacoustic computed tomography and ultrasound computed tomography for reconstructing the structural and functional information of human finger joint systems. The fused multispectral photoacoustic-ultrasound computed tomography (MPAUCT) system was examined by the phantom and in vivo experimental tests. The imaging results indicate that the hard tissues such as the bones and the soft tissues including the blood vessels, the tendon, the skins, and the subcutaneous tissues in the finger joints systems can be effectively recovered by using our multimodality MPAUCT system. The developed MPAUCT system is able to provide us with more comprehensive information of the human finger joints, which shows its potential for characterization and diagnosis of bone or joint diseases. PMID:27774453

  9. Dual-Modality Imaging of the Human Finger Joint Systems by Using Combined Multispectral Photoacoustic Computed Tomography and Ultrasound Computed Tomography

    Directory of Open Access Journals (Sweden)

    Yubin Liu

    2016-01-01

    Full Text Available We developed a homemade dual-modality imaging system that combines multispectral photoacoustic computed tomography and ultrasound computed tomography for reconstructing the structural and functional information of human finger joint systems. The fused multispectral photoacoustic-ultrasound computed tomography (MPAUCT system was examined by the phantom and in vivo experimental tests. The imaging results indicate that the hard tissues such as the bones and the soft tissues including the blood vessels, the tendon, the skins, and the subcutaneous tissues in the finger joints systems can be effectively recovered by using our multimodality MPAUCT system. The developed MPAUCT system is able to provide us with more comprehensive information of the human finger joints, which shows its potential for characterization and diagnosis of bone or joint diseases.

  10. Use of dual-energy X-ray absorptiometry in obese individuals: The possibility to estimate whole body composition from DXA half-body scans

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, K. [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm (Sweden)], E-mail: kent.lundqvist@karolinska.se; Neovius, M. [Obesity Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, SE-141 86 Stockholm (Sweden); Grigorenko, A. [Research and Development Unit, YLab Wellcare Institute, SE-113 60 Stockholm (Sweden); Nordenstroem, J. [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm (Sweden); Roessner, S. [Obesity Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, SE-141 86 Stockholm (Sweden)

    2009-02-15

    Background: Because of its high accuracy, dual-energy X-ray absorptiometry (DXA) has become one of the most frequently used methods for estimating human body composition. One limiting factor concerning measuring obese people with the DXA technique is the size of the scanning area. Objective: To explore the possibility of estimating whole body composition from half-body scans before and after weight reduction, and compare the results with densitometry measurements. Design: Intervention study of 15 obese adults (age 47.2 {+-} 13.4; BMI 35.9 {+-} 3.1) who were measured with full- and half-body DXA scans before and after a 7-week weight loss program. On both occasions, body composition was also assessed with air-displacement plethysmography (ADP). Results: The mean weight loss at follow-up was 14.9 {+-} 4.1 kg (5.0 kg/m{sup 2}), corresponding to a 14% decrease in body weight. When comparing the results from full- and half-body DXA, between 96% and 98% of the variance was explained. At baseline, %Body Fat (%BF) did not differ significantly between full and half-body measurements (0.6, -0.1-1.3), but the half-body method overestimated it by 1.0% (0.2-1.8) at follow-up. On the contrary, the difference between DXA and ADP in the assessment of %BF was both significant and of large magnitude (5.2; 2.4-8.0) at baseline, while non-significant and near zero (0.4; -1.3-2.2) at follow-up when the subjects had lost a significant amount of weight. Conclusion: The results obtained from half-body DXA scans can accurately predict whole body composition, as measured by full-body DXA, before and after significant weight reduction, in obese patients who barely fit into the scanning area. However, increasing discordance between DXA and ADP with increasing adiposity was seen, indicating that the measurements might not be as reliable on extreme obese subjects as on normal and overweight ditto.

  11. Informing energy and climate policies using energy systems models insights from scenario analysis increasing the evidence base

    CERN Document Server

    Giannakidis, George; Ó Gallachóir, Brian; Tosato, GianCarlo

    2015-01-01

    This book highlights how energy-system models are used to underpin and support energy and climate mitigation policy decisions at national, multi-country and global levels. It brings together, for the first time in one volume, a range of methodological approaches and case studies of good modeling practice on a national and international scale from the IEA-ETSAP energy technology initiative. It provides insights for the reader into the rich and varied applications of energy-system models and the underlying methodologies and policy questions they can address. The book demonstrates how these mode

  12. Energy-efficient window systems. Effects on energy use and daylight in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Buelow-Huebe, H.

    2001-11-01

    This thesis deals with energy-efficient windows in Swedish buildings. Parametric studies were performed in the dynamic energy simulation tool Derob-LTH in order to study the effects of window choices on energy use and indoor climate for both residential and office buildings. A steady-state program was used to evaluate two years of measurements of energy use and indoor temperatures of an energy-efficient row-house. Two behavioural studies regarding (1) daylight transmittance, view and room perception using super-insulated windows and (2) the satisfaction with the daylight environment and the use of shading devices in response to daylight/sunlight were conducted in full-scale laboratory environments exposed to the natural climate. Results show that as the energy-efficiency of buildings increase, window U-values must decrease in order not to increase the annual heating demand, since the heating season is shortened, and useful solar gains become smaller. For single-family houses with a window-to-floor area ratio of 15 % and insulated according the current Swedish building code, the U-values should thus on average be lower than 1.0 W/m{sup 2}K. For houses insulated according to 1960s standard, the U-value may on average be 1.6 W/m{sup 2}K. For colder climates (northern Sweden), the U-values should be somewhat lower, while slightly higher U-values can be tolerated in milder climates of south Sweden. Thermal comfort during winter is improved for energy-efficient windows. However, overheating problems exist for both super-insulated houses and highly glazed office buildings showing a need for very low U-values in combination with low g-values. Daylight experiments indicate that the use of two low-emittance coatings tints the transmitted daylight enough to be appreciated, and colours may be perceived as more drab and rooms more enclosed. A compromise between energy-efficiency and daylighting may be needed, and it is suggested that only one coating be used except when very

  13. Benefits of using virtual energy storage system for power system frequency response

    OpenAIRE

    Cheng, Meng; Sami, Saif Sabah; Wu, Jianzhong

    2016-01-01

    This paper forms a Virtual Energy Storage System (VESS) and validates that VESS is an innovative and cost-effective way to provide the function of conventional Energy Storage Systems (ESSs) through the utilization of the present network assets represented by the flexible demand. The VESS is a solution to convert to a low carbon power system and in this paper, is modelled to store and release energy in response to regulation signals by coordinating the Demand Response (DR) from domestic refrig...

  14. A deep learning framework for the automated inspection of complex dual-energy x-ray cargo imagery

    Science.gov (United States)

    Rogers, Thomas W.; Jaccard, Nicolas; Griffin, Lewis D.

    2017-05-01

    Previously, we investigated the use of Convolutional Neural Networks (CNNs) to detect so-called Small Metallic Threats (SMTs) hidden amongst legitimate goods inside a cargo container. We trained a CNN from scratch on data produced by a Threat Image Projection (TIP) framework that generates images with realistic variation to robustify performance. The system achieved 90% detection of containers that contained a single SMT, while raising 6% false positives on benign containers. The best CNN architecture used the raw high energy image (single-energy) and its logarithm as input channels. Use of the logarithm improved performance, thus echoing studies on human operator performance. However, it is an unexpected result with CNNs. In this work, we (i) investigate methods to exploit material information captured in dual-energy images, and (ii) introduce a new CNN training scheme that generates `spot-the-difference' benign and threat pairs on-the-fly. To the best of our knowledge, this is the first time that CNNs have been applied directly to raw dual-energy X-ray imagery, in any field. To exploit dual-energy, we experiment with adapting several physics-derived approaches to material discrimination from the cargo literature, and introduce three novel variants. We hypothesise that CNNs can implicitly learn about the material characteristics of objects from the raw dual-energy images, and use this to suppress false positives. The best performing method is able to detect 95% of containers containing a single SMT, while raising 0.4% false positives on benign containers. This is a step change improvement in performance over our prior work

  15. Priority order in using biomass resources - Energy systems analyses of future scenarios for Denmark

    DEFF Research Database (Denmark)

    Kwon, Pil Seok; Østergaard, Poul Alberg

    2013-01-01

    for the decrease of biomass are made by use of an hourly energy system analysis model, EnergyPLAN. The results are shown in terms of system configuration, biomass fuel efficiency, system cost, and impacts on the export of electricity. It is concluded that the reduction of biomass in the heat sector is better than......According to some future Danish energy scenarios, biomass will become one of the two main pillars of the future energy system accompanied by wind power. The biomass can be used for generating heat and electricity, and as a transportation fuel in a future energy system according to the scenarios....... This article compares the value of using biomass as a heat source and for electricity generation in a 100% renewable energy system context. The comparison is done by assuming an incremental decrease in the biomass available for the electricity and heat sector, respectively. The assumed scenarios...

  16. Dual energy subtraction method for breast calcification imaging

    Science.gov (United States)

    Koukou, Vaia; Martini, Niki; Fountos, George; Michail, Christos; Sotiropoulou, Panagiota; Bakas, Athanasios; Kalyvas, Nektarios; Kandarakis, Ioannis; Speller, Robert; Nikiforidis, George

    2017-03-01

    The aim of this work was to present an experimental dual energy (DE) method for the visualization of microcalcifications (μCs). A modified radiographic X-ray tube combined with a high resolution complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) X-ray detector was used. A 40/70 kV spectral combination was filtered with 100 μm cadmium (Cd) and 1000 μm copper (Cu) for the low/high-energy combination. Homogenous and inhomogeneous breast phantoms and two calcification phantoms were constructed with various calcification thicknesses, ranging from 16 to 152 μm . Contrast-to-noise ratio (CNR) was calculated from the DE subtracted images for various entrance surface doses. A calcification thickness of 152 μm was visible, with mean glandular doses (MGD) in the acceptable levels (below 3 mGy). Additional post-processing on the DE images of the inhomogeneous breast phantom resulted in a minimum visible calcification thickness of 93 μm (MGD=1.62 mGy). The proposed DE method could potentially improve calcification visibility in DE breast calcification imaging.

  17. Using Terahertz Spectroscopy to Study Systems with Solar Energy Applications

    Science.gov (United States)

    Milot, Rebecca L.; Moore, Gary F.; Martini, Lauren A.; Brudvig, Gary W.; Crabtree, Robert H.; Schmuttenmaer, Charles A.

    2013-06-01

    Biomimetic solar water oxidation systems are being developed as renewable alternatives to fossil fuels. One possible design incorporates thin-film dye-sensitized nanoparticle photoanades to capture and convert visible light to charge carriers and catalysts to facilitate water oxidation. The physical properties of the dye are important due to its position as the light absorber and electron transfer initiator. Given the role that porphyrins play in photosynthesis and their synthetic tunability, they are promising components for these photoanodes. Time-Resolved THz Spectroscopy (TRTS), an optical pump/THz probe technique, is a non-contact electrical probe with proven usefulness for studying electron transfer and conductivity on a sub-picosecond timescale. Using TRTS, the efficiency and dynamics of electron injection from porphyrin dyes into metal oxide surfaces was found to be strongly influenced by the structure and photophysical properties of the dye.

  18. Climate and energy scenarios for Ireland to 2050 using the Irish TIMES energy systems model

    OpenAIRE

    Chiodi, Alessandro

    2014-01-01

    Due to growing concerns regarding the anthropogenic interference with the climate system, countries across the world are being challenged to develop effective strategies to mitigate climate change by reducing or preventing greenhouse gas (GHG) emissions. The European Union (EU) is committed to contribute to this challenge by setting a number of climate and energy targets for the years 2020, 2030 and 2050 and then agreeing effort sharing amongst Member States. This thesis focus on one Member S...

  19. Actuator System with Dual Chambers

    DEFF Research Database (Denmark)

    2015-01-01

    (8), the lid having a shaft opening (17) for a shaft (6) coupled to the magnetic rotor (5), wherein the magnetic rotor (5), when inserted in the translator cylinder (2), is arranged to translate a linear movement of the translator cylinder (2) into a rotational movement of the magnetic rotor by using...... magnetic flux (82) interacting between the magnetic stator and the magnetic rotor, said rotational movements is being transferred through a shaft (6), the lid (8) with a shaft opening (17) arranged for receiving the shaft (6), wherein the shaft is arranged to make both the linear and the rotational...... movement in the shaft opening (17), the lid (8) being arranged for confining the second end (15) of the translator cylinder (2), the translator cylinder confined by the lid (8) forms,when divided by the magnetic rotor (5), a first chamber (TC) with a first volume and a second chamber(BC) with a second...

  20. Dual-Cell HSDPA for Network Energy Saving

    DEFF Research Database (Denmark)

    Micallef, Gilbert

    2010-01-01

    consumption. This paper proposes an energy saving feature that exploits variations in network traffic. Based on the individual load of each sector, the feature determines if the secondary carrier is detrimental for reaching some pre-set minimum requirements. Each sector is allowed to switch off one......The increasing demand for mobile broadband is pushing existing 3G networks closer to their capacity limit. Additional carriers together with new HSPA features (HSPA+) are expected to provide the next necessary boost in network capacity. One specific feature in HSPA+ is referred to as Dual......-Cell HSDPA (or Dual-Carrier HSDPA). This feature allows for a single user to be simultaneously scheduled over two carriers, effectively doubling its achievable data rate. The addition of a secondary carrier will require additional radio equipment at the base station site, increasing the overall energy...

  1. ENERGY-NET (Energy, Environment and Society Learning Network): Enhancing opportunities for learning using an Earth systems science framework

    Science.gov (United States)

    Elliott, E. M.; Bain, D. J.; Divers, M. T.; Crowley, K. J.; Povis, K.; Scardina, A.; Steiner, M.

    2012-12-01

    We describe a newly funded collaborative NSF initiative, ENERGY-NET (Energy, Environment and Society Learning Network), that brings together the Carnegie Museum of Natural History (CMNH) with the Learning Science and Geoscience research strengths at the University of Pittsburgh. ENERGY-NET aims to create rich opportunities for participatory learning and public education in the arena of energy, the environment, and society using an Earth systems science framework. We build upon a long-established teen docent program at CMNH and to form Geoscience Squads comprised of underserved teens. Together, the ENERGY-NET team, including museum staff, experts in informal learning sciences, and geoscientists spanning career stage (undergraduates, graduate students, faculty) provides inquiry-based learning experiences guided by Earth systems science principles. Together, the team works with Geoscience Squads to design "Exploration Stations" for use with CMNH visitors that employ an Earth systems science framework to explore the intersecting lenses of energy, the environment, and society. The goals of ENERGY-NET are to: 1) Develop a rich set of experiential learning activities to enhance public knowledge about the complex dynamics between Energy, Environment, and Society for demonstration at CMNH; 2) Expand diversity in the geosciences workforce by mentoring underrepresented teens, providing authentic learning experiences in earth systems science and life skills, and providing networking opportunities with geoscientists; and 3) Institutionalize ENERGY-NET collaborations among geosciences expert, learning researchers, and museum staff to yield long-term improvements in public geoscience education and geoscience workforce recruiting.

  2. Analytical Comparison of Dual-Input Isolated dc-dc Converter with an ac or dc Inductor for Renewable Energy Systems

    DEFF Research Database (Denmark)

    Zhang, Zhe; Mira Albert, Maria del Carmen; Andersen, Michael A. E.

    2017-01-01

    This paper presents two configurations of dualinput (DI) or three-port (TPC) isolated dc-dc converters for hybrid renewable energy systems such as photovoltaics and batteries. These two converters are derived by integrating an interleaved boost converter and a single-active bridge converter...

  3. Adoption and Abandonment of Dual Exchange Rate Systems Adoption and Abandonment of Dual Exchange Rate Systems

    Directory of Open Access Journals (Sweden)

    Jose Saul Lizondo

    1990-03-01

    Full Text Available Adoption and Abandonment of Dual Exchange Rate Systems When facing persistent balance of payments problems, some countries have resorted to a dual exchange rate system as an alternative to a uniform exchange rate adjustment. Typically, under the dual system, certain selected transactions take place at a fixed official exchange rate, while there remaining transactions are effected at a more depreciated rate, which is usually determined by market forces. This paper examines the circumstances that lead to the adoption of a dual system, and the conditions under which the foreign exchange market can be unified successfully or a later stage. In this paper, the adoption of the dual system is linked to the unsustainability of a crawling peg (or a fixed exchange rate system in the presence of large budgret deficits. We show that the initiai spiral between the financial at the commercial exchange rates and the extent of capital flight largely depends on whether the switch in regime is anticipated or unanticipated. Although the dual system improves the external position of the economy, to the extent that there is no change in domestic noticies the country will continue to experience a deficit in the balance of payments. A correction of these policies is the only enduring solution to the external imbalance, and a precondition for a successful unification of the foreirg exchange market. If the economv unifies the foreign exchange market into a crawling peg, the financial exchahnge rate could be an adequate indicator of the initlal level of which the new exchange rate should be set if a capital outflow is to be avoided. If the economy instead moves to a flexible exchange rate system, the initial value of the exchange rate could be higher or lower than the prevailing financial exchange rate.

  4. CLASSICAL AND MODERN METHODS USED IN ELECTRICAL ENERGY MANAGEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    Petruta MIHAI

    2014-11-01

    Full Text Available The forecast can be defined like approximately of the unknown events from the future; this thing is necessary because of the existence of some unknown events, but this events play an important role in taking some decisions. It is obvious that the uncertainty's elimination is not possible, so the forecast is a tool who tries to minimalize this uncertainties. The forecast's importance in the electrical energy management is very important. The forecast of the energy's request presumes the estimation of this request's characteristics: size, time evolution, the request's structure, and so on. The forecast of the electrical charge is a tool of a modern EMS.

  5. Dichromatic source for the application of dual-energy tissue cancellation in mammography

    Science.gov (United States)

    Tuffanelli, Alessandra; Fabbri, S.; Marziani, Michele; Taibi, Angelo; Sarnelli, A.; Gambaccini, Mauro

    2002-05-01

    A novel x-ray source, providing dichromatic beams for the application of dual-energy radiography, has been assembled and studied. The system works via Bragg diffraction, by monochromatizing the beam produced by a conventional W-anode x-ray tube with a mosaic crystal monochromator. The source generates a laminar beam (10 cm-high and 0.8 cm-wide), composed by two spatially superimposed quasi-monochromatic beams. The characteristics of the radiation field in terms of energy resolution and fluence have been reported, for three pairs of energies. A study of the spectra attenuated by several phantoms of breast equivalent tissue of different thicknesses shows that the optimal energy of the dichromatic beam for dual energy mammography application ranges between 18/36 keV and 18.6/37.2 keV and may be set as a function of the thickness or density of investigated tissue.

  6. Comprehensive Evaluation of Methanol Synthesis and Utilization System for Making Use of Remote Wind Power Energy

    Science.gov (United States)

    Morimoto, Shin'Ichiro; Pak, Pyong Sik; Liu, Wei; Kosugi, Takanobu

    For the purpose of mitigating carbon dioxide emissions, three renewable energy transportation systems are proposed in which methanol is synthesized by use of wind power generation energy at an oversea and is transported to Japan to be used for a power generation. The proposed systems are the following three systems: (1) wind energy and captured CO2 utilization system, (2) wind energy and coal utilization system, and (3) wind energy and biomass utilization system. The characteristic and cost of the proposed systems’ components such as a wind power generation and a methanol synthesis plants are investigated, and so are the energy and carbon flows of the systems, assuming that the wind power generation plant is constructed at the eastern coast of Russia. Major indicators such as energy efficiency, methanol cost, CO2 reduction cost, etc., of the proposed systems are evaluated together with those of a similar CO2 recycling system utilizing hydraulic power. On the basis of the evaluation results, the wind energy and biomass utilization system is shown to be the most excellent among the evaluated systems from the viewpoints of the CO2 reduction cost. When LNG cost is increased, its estimated CO2 reduction cost islower than that of a CO2 recovery system adopted to a conventional LNG-fired power plant. Consequently, the proposed system is expected to be a feasible option for CO2 reduction in the near future when the wind power generation cost is much decreased.

  7. Energy information systems (EIS): Technology costs, benefit, and best practice uses

    Energy Technology Data Exchange (ETDEWEB)

    Granderson, Jessica; Lin, Guanjing; Piette, Mary Ann

    2013-11-26

    Energy information systems are the web-based software, data acquisition hardware, and communication systems used to store, analyze, and display building energy data. They often include analysis methods such as baselining, benchmarking, load profiling, and energy anomaly detection. This report documents a large-scale assessment of energy information system (EIS) uses, costs, and energy benefits, based on a series of focused case study investigations that are synthesized into generalizable findings. The overall objective is to provide organizational decision makers with the information they need to make informed choices as to whether or not to invest in an EIS--a promising technology that can enable up to 20 percent site energy savings, quick payback, and persistent low-energy performance when implemented as part of best-practice energy management programs.

  8. A Modified C-Dump Converter for BLDC Machine Used in a Flywheel Energy Storage System

    Directory of Open Access Journals (Sweden)

    Bandaru Ramakrishna

    2014-10-01

    Full Text Available This paper presents a modified C-dump converter for brushless DC (BLDC machine used in the flywheel energy storage system. The converter can realize the energy bidirectional flowing and has the capability to recover the energy extracted from the turnoff phase of the BLDC machine. The principle of operation, modeling, and control strategy of the system has been investigated in the paper. Simulation and experimental results of the proposed system are also presented and discussed.

  9. Dual-energy computed tomography for gout diagnosis and management.

    Science.gov (United States)

    Dalbeth, Nicola; Choi, Hyon K

    2013-01-01

    The central feature of gout is deposition of monosodium urate crystals. Dual-energy computed tomography (DECT) is a recently developed advanced imaging method that enables visualisation of urate deposits by analysis of the chemical composition of the scanned materials. This review summarises recent research describing the use of DECT in gout management. This technology may assist in both diagnosis and monitoring of the disease. Studies of patients with established disease indicate diagnostic accuracy for gout is high. Excellent inter-reader agreement has been reported for detection of urate deposits by use of DECT. Automated volume assessment software also enables rapid and reproducible measurement of urate deposits within tophi, suggesting that this modality may be useful for monitoring the disease. Although several case reports indicate DECT can be used to reveal reduction in the size of urate deposits, the sensitivity to change in response to urate-lowering therapy has not yet been systematically reported. DECT images reveal variable urate deposition within tophi of the same physical size. The ability to visualise urate deposits in tissue may provide new insights into the pathology and mechanisms of gout.

  10. Discomfort glare with complex fenestration systems and the impact on energy use when using daylighting control

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Sabine; McNeil, Andrew; Lee, Eleanor S.; Kalyanam, Raghuram

    2015-11-03

    Glare is a frequent issue in highly glazed buildings. A modelling approach is presented that uses discomfort glare probability and discomfort glare index as metrics to determine occupants’ behaviour. A glare control algorithm that actuated an interior shade for glare protection based on the predicted perception was implemented in a building simulation program. A reference case with a state-of-the-art base glazing was compared to the same glazing but with five different complex fenestration systems, i.e., exterior shades. The windows with exterior shades showed significant variations in glare frequencies. Energy use intensity in a prototypical office building with daylighting controls was greatly influenced for the systems with frequent glare occurrence. While the base glazing could benefit from glare control, some of the exterior shades showed significantly greater energy use when discomfort glare-based operation of interior shades was considered.

  11. Multisource energy system project

    Science.gov (United States)

    Dawson, R. W.; Cowan, R. A.

    1987-03-01

    The mission of this project is to investigate methods of providing uninterruptible power to Army communications and navigational facilities, many of which have limited access or are located in rugged terrain. Two alternatives are currently available for deploying terrestrial stand-alone power systems: (1) conventional electric systems powered by diesel fuel, propane, or natural gas, and (2) alternative power systems using renewable energy sources such as solar photovoltaics (PV) or wind turbines (WT). The increased cost of fuels for conventional systems and the high cost of energy storage for single-source renewable energy systems have created interest in the hybrid or multisource energy system. This report will provide a summary of the first and second interim reports, final test results, and a user's guide for software that will assist in applying and designing multi-source energy systems.

  12. Visualization of the dissipation of energy during the cutting process. Presentation of energy value flows by means of dual energy signatures; Energieverschwendung beim Zerspanungsprozess sichtbar machen. Darstellung von Energiewertstroemen mittels dualer Energiesignaturen

    Energy Technology Data Exchange (ETDEWEB)

    Schillig, Rainer [Hochschule Aalen (Germany). Professur Fertigungsorganisation und Prozessmanagement; Kalhoefer, Eckehard [Hochschule Aalen (Germany). Stiftungslehrstuhl Spanende Fertigung; Stock, Timo [Hochschule Aalen (Germany). Studiengang Maschinenbau/Produktion und Management

    2012-09-15

    Lean production systems are the minimization of wastage. Therefore, process steps are divided in value-added and non-value-added process steps. Using the value stream analysis non-value-adding process shares can be identified easily.The main aim usually are the two factors processing time and inventory. By means of a cutting process, the authors of the paper under consideration report on a method which divides the process-related utilization of energy in value-adding and non-value-adding energy use. Due to the dual consideration of energy use, the energy consumption can be easily integrated in the value stream analysis.

  13. A New Method for Solving General Dual Fuzzy Linear Systems

    Directory of Open Access Journals (Sweden)

    M. Otadi

    2013-09-01

    Full Text Available . According to fuzzy arithmetic, general dual fuzzy linear system (GDFLS cannot be replaced by a fuzzy linear system (FLS. In this paper, we use new notation of fuzzy numbers and convert a GDFLS to two linear systems in crisp case, then we discuss complexity of the proposed method. Conditions for the existence of a unique fuzzy solution to n × n GDFLS are derived

  14. Dual energy CT myelography after lumba osteosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Grams, A.E.; Gizewski, E.R. [Medical Univ. Innsbruck (Austria). Dept. of Neuroradiology; Sender, J.; Obert, M. [Univ. Hospital Giessen (Germany). Dept. of Neuroradiology; Mortiz, R.; Krombach, G.A. [Univ. Hospital Giessen (Germany). Dept. of Radiology; Stein, M. [Univ. Hospital Giessen (Germany). Dept. of Neurosurgery; Oertel, M. [Vogtland-Klinikum Plauen (Germany). Dept. of Neurosurgery; Schmidt, T. [Klinikum Wuppertal (Germany). Dept. of Neuroradiology

    2014-07-15

    The purpose of this study was to evaluate the benefits of CT myelography in the DE technique in patients with lumbar osteosynthesis. In 30 patients a DE-CT scan of the spine with tube voltages of 80 kV and 140 kV was performed and a virtual monochromatic series of 120 kV was generated after intrathecal contrast injection. The impact of metal artifacts on the spinal canal and the spinal foramina was evaluated. The visualization of nerve roots was compared between a VRT series of the dural sac and conventional myelography. With tube voltages of 140 kV, the artifacts were least pronounced. As no overlay disturbance was present, VRT visualization of the nerve roots was more reliable than conventional myelography. In patients after osteosynthesis, CT in the DE technique provides minimal artifact disturbance using a tube voltage of 140 kV. ''Virtual myelography'' seems to be superior to conventional myelography for the evaluation of nerve roots. This could reduce additional conventional radiography, may shorten the entire examination and radiation time and diminish unnecessary painful movements for the patient.

  15. Comparison of Efficiencies of Solar Tracker systems with static panel Single- Axis Tracking System and Dual-Axis Tracking System with Fixed Mount

    Directory of Open Access Journals (Sweden)

    Dhanabal.R

    2013-04-01

    Full Text Available Electricity plays a key role now in our daily lives but the energy sources to electric power has been used in abundance and so researchers were compelled to find an alternate source of power leading to the discovery of solar energy. Solar energy is inexhaustible and eco-friendly and can be converted into electricityusing photovoltaic panels. These panels can be used in a fixed form or used in a solar tracking system for single axis as well as for dual axis. In a fixed form their efficiency is low since the panels will be tilted in a particular angle whereas in a tracking system the panel is made to move either in single axis or dual axis. In a single axis system the panel is moved in an east to west direction with respect to the sun and it has better efficiency than panels in fixed form. But in a dual axis system the panel is made to rotate in all four directions in accordance with the sun. And dual axis has proved to have more efficiency than both fixed panels and single axis system.

  16. Utility of single-energy and dual-energy computed tomography in clot characterization: An in-vitro study.

    Science.gov (United States)

    Brinjikji, Waleed; Michalak, Gregory; Kadirvel, Ramanathan; Dai, Daying; Gilvarry, Michael; Duffy, Sharon; Kallmes, David F; McCollough, Cynthia; Leng, Shuai

    2017-06-01

    Background and purpose Because computed tomography (CT) is the most commonly used imaging modality for the evaluation of acute ischemic stroke patients, developing CT-based techniques for improving clot characterization could prove useful. The purpose of this in-vitro study was to determine which single-energy or dual-energy CT techniques provided optimum discrimination between red blood cell (RBC) and fibrin-rich clots. Materials and methods Seven clot types with varying fibrin and RBC densities were made (90% RBC, 99% RBC, 63% RBC, 36% RBC, 18% RBC and 0% RBC with high and low fibrin density) and their composition was verified histologically. Ten of each clot type were created and scanned with a second generation dual source scanner using three single (80 kV, 100 kV, 120 kV) and two dual-energy protocols (80/Sn 140 kV and 100/Sn 140 kV). A region of interest (ROI) was placed over each clot and mean attenuation was measured. Receiver operating characteristic curves were calculated at each energy level to determine the accuracy at differentiating RBC-rich clots from fibrin-rich clots. Results Clot attenuation increased with RBC content at all energy levels. Single-energy at 80 kV and 120 kV and dual-energy 80/Sn 140 kV protocols allowed for distinguishing between all clot types, with the exception of 36% RBC and 18% RBC. On receiver operating characteristic curve analysis, the 80/Sn 140 kV dual-energy protocol had the highest area under the curve for distinguishing between fibrin-rich and RBC-rich clots (area under the curve 0.99). Conclusions Dual-energy CT with 80/Sn 140 kV had the highest accuracy for differentiating RBC-rich and fibrin-rich in-vitro thrombi. Further studies are needed to study the utility of non-contrast dual-energy CT in thrombus characterization in acute ischemic stroke.

  17. A case study of energy use and economical analysis of irrigated and dryland wheat production systems

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani, Reza; Mondani, Farzad; Amirmoradi, Shahram; Feizi, Hassan; Khorramdel, Surror; Teimouri, Mozhgan; Sanjani, Sara; Anvarkhah, Sepideh; Aghel, Hassan [Faculty of Agriculture, Ferdowsi University of Mashhad, P.O. Box 91775-1163, Mashhad (Iran)

    2011-01-15

    Current conventional agricultural systems using intensive energy has to be re-vitalized by new integrated approaches relying on renewable energy resources, which can allow farmers to stop depending on fossil resources. The aim of the present study was to compare wheat production in dryland (low input) and irrigated (high input) systems in terms of energy ratio, energy efficiency, benefit/cost ratio and amount of renewable energy use. Data were collected from 50 irrigated and 50 dryland wheat growers by using a face-to-face questionnaire in 2009. The results showed that the total energy requirement under low input was 9354.2 MJ ha{sup -1}, whereas under high input systems it was 45367.6 MJ ha{sup -1}. Total energy input consumed in both dryland and irrigated systems could be classified as direct, indirect, renewable and non-renewable energies which average in two wheat production systems were 47%, 53%, 24% and 76%, respectively. Energy ratios of 3.38 in dryland and 1.44 in irrigated systems were achieved. The benefit-cost ratios were 2.56 in dryland and 1.97 in irrigated wheat production systems. Based on the results of the present study, dry-land farming can have a significant positive effect on energy-related factors especially in dry and semi-dry climates such as Iran. (author)

  18. Development of anode zone using dual-anode system to reduce organic matter crossover in membraneless microbial fuel cells.

    Science.gov (United States)

    Kim, Jisu; Kim, Bongkyu; An, Junyeong; Lee, Yoo Seok; Chang, In Seop

    2016-08-01

    To prevent the occurrence of the organic crossover in membraneless microbial fuel cells (ML-MFCs), dual-anode MFC (DA-MFC) was designed from multi-anode concept to ensure anode zone. The anode zone addressed increase the utilization of organic matter in ML-MFCs, as the result, the organic crossover was prevented and performance of MFCs were enhanced. The maximum power of the DA-MFC was 0.46mW, which is about 1.56 times higher than the ML-MFC (0.29mW). Furthermore, the DA-MFC had advantage in correlation of organic substance concentration and dissolved oxygen concentration, and even electric over-potential. In addition, in terms of cathode fouling, the DA-MFC showed clearer surface. Hence, the anode zone should be considered in the advanced ML-MFC for practically use in wastewater treatment process, and also for scale-up of MFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Allocation of Energy Use in the Biomass-based Fuel Ethanol System and Its Use in Decision Making

    Institute of Scientific and Technical Information of China (English)

    LENG Ru-bo; YU Sui-ran; FANG Fang; DAI Du; WANG Cheng-tao

    2005-01-01

    The Chinese government is developing biomass ethanol as one of its automobile fuels for energy security and environmental improvement reasons. The energy efficiency of the biomass-based fuel ethanol is critical issue. To investigate the energy use in the three biomass-base ethanol fuel systems, energy content approach, Market value approach and Product displacement approach methods were used to allocate the energy use based on life cycle energy assessment. The results shows that the net energy of corn based, wheat based, and cassava-based ethanol fuel are 12543MJ, 10299MJ and 13112MJ when get one ton biomassbased ethanol, respectively, and they do produce positive net energy.

  20. Spacecraft Energy Storage Systems

    OpenAIRE

    Robinson, Wilf; Hanks, James; Spina, Len; Havenhill, Doug; Gisler, Gary; Ginter, Steve; Brault, Sharon

    1997-01-01

    Flywheel Energy Storage Systems represent an exciting alternative to traditional battery storage systems used to power satellites during periods of eclipse. The increasing demand for reliable communication and data access is driving explosive growth in the number of satellite systems being developed as well as their performance requirements. Power on orbit is the key to this performance, and batteries are becoming increasingly unattractive as an energy storage media. Flywheel systems offer ve...

  1. Optimal use of organic waste in future energy systems - the Danish case

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, M.; Lund, H. [Aalborg Univ., Dept. of Development and Planning (Denmark)

    2007-05-15

    This paper presents a comparative energy system analysis of different technologies utilizing organic waste for heat, power and fuel for transport production. Technologies included in the analysis are 2nd generation bio-fuel production, gasification, fermentation (biogas production) and improved incineration. It is argued that it is important to assess energy technologies together with the energy systems they are part of and influence. The energy system analysis is performed using the EnergyPLAN model, which simulates the Danish energy system hour by hour. The analysis shows that most fuel is saved by gasifying the organic waste and using the syngas for CHP production. On the other hand least greenhouse gases are emitted if biogas is produced from organic waste and used for CHP production. (au)

  2. A dual cone-beam CT system for image guided radiotherapy: Initial performance characterization

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Bowsher, James; Yin Fangfang [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Giles, William [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2013-02-15

    Purpose: The purpose of this study is to evaluate the performance of a recently developed benchtop dual cone-beam computed tomography (CBCT) system with two orthogonally placed tube/detector sets. Methods: The benchtop dual CBCT system consists of two orthogonally placed 40 Multiplication-Sign 30 cm flat-panel detectors and two conventional x-ray tubes with two individual high-voltage generators sharing the same rotational axis. The x-ray source to detector distance is 150 cm and x-ray source to rotational axis distance is 100 cm for both subsystems. The objects are scanned through 200 Degree-Sign of rotation. The dual CBCT system utilized 110 Degree-Sign of projection data from one detector and 90 Degree-Sign from the other while the two individual single CBCTs utilized 200 Degree-Sign data from each detector. The system performance was characterized in terms of uniformity, contrast, spatial resolution, noise power spectrum, and CT number linearity. The uniformities, within the axial slice and along the longitudinal direction, and noise power spectrum were assessed by scanning a water bucket; the contrast and CT number linearity were measured using the Catphan phantom; and the spatial resolution was evaluated using a tungsten wire phantom. A skull phantom and a ham were also scanned to provide qualitative evaluation of high- and low-contrast resolution. Each measurement was compared between dual and single CBCT systems. Results: Compared to single CBCT, the dual CBCT presented: (1) a decrease in uniformity by 1.9% in axial view and 1.1% in the longitudinal view, as averaged for four energies (80, 100, 125, and 150 kVp); (2) comparable or slightly better contrast (0{approx}25 HU) for low-contrast objects and comparable contrast for high-contrast objects; (3) comparable spatial resolution; (4) comparable CT number linearity with R{sup 2}{>=} 0.99 for all four tested energies; (5) lower noise power spectrum in magnitude. Dual CBCT images of the skull phantom and the

  3. Development of Residential Prototype Building Models and Analysis System for Large-Scale Energy Efficiency Studies Using EnergyPlus

    Energy Technology Data Exchange (ETDEWEB)

    Mendon, Vrushali V.; Taylor, Zachary T.

    2014-09-10

    ABSTRACT: Recent advances in residential building energy efficiency and codes have resulted in increased interest in detailed residential building energy models using the latest energy simulation software. One of the challenges of developing residential building models to characterize new residential building stock is to allow for flexibility to address variability in house features like geometry, configuration, HVAC systems etc. Researchers solved this problem in a novel way by creating a simulation structure capable of creating fully-functional EnergyPlus batch runs using a completely scalable residential EnergyPlus template system. This system was used to create a set of thirty-two residential prototype building models covering single- and multifamily buildings, four common foundation types and four common heating system types found in the United States (US). A weighting scheme with detailed state-wise and national weighting factors was designed to supplement the residential prototype models. The complete set is designed to represent a majority of new residential construction stock. The entire structure consists of a system of utility programs developed around the core EnergyPlus simulation engine to automate the creation and management of large-scale simulation studies with minimal human effort. The simulation structure and the residential prototype building models have been used for numerous large-scale studies, one of which is briefly discussed in this paper.

  4. Small Wind Energy Systems

    DEFF Research Database (Denmark)

    2017-01-01

    This chapter intends to serve as a brief guide when someone is considering the use of wind energy for small power applications. It is discussed that small wind energy systems act as the major energy source for residential or commercial applications, or how to make it part of a microgrid...... as a distributed generator. In this way, sources and loads are connected in such a way to behave as a renewable dispatch center. With this regard, non-critical loads might be curtailed or shed during times of energy shortfall or periods of high costs of energy production. If such a wind energy system is connected...... to the public distibutor, it can serve as a backup system, as a non-interruptible power supply (with storage aggregation), provide low-voltage support, or give a clean surplus of energy transferred to the public network under economical and technological basis. In this chapter, several factors are also...

  5. Benefits of texture analysis of dual energy CT for Computer-Aided pulmonary embolism detection.

    Science.gov (United States)

    Foncubierta-Rodríguez, Antonio; Jiménez del Toro, Óscar Alfonso; Platon, Alexandra; Poletti, Pierre-Alexandre; Müller, Henning; Depeursinge, Adrien

    2013-01-01

    Pulmonary embolism is an avoidable cause of death if treated immediately but delays in diagnosis and treatment lead to an increased risk. Computer-assisted image analysis of both unenhanced and contrast-enhanced computed tomography (CT) have proven useful for diagnosis of pulmonary embolism. Dual energy CT provides additional information over the standard single energy scan by generating four-dimensional (4D) data, in our case with 11 energy levels in 3D. In this paper a 4D texture analysis method capable of detecting pulmonary embolism in dual energy CT is presented. The method uses wavelet-based visual words together with an automatic geodesic-based region of interest detection algorithm to characterize the texture properties of each lung lobe. Results show an increase in performance with respect to the single energy CT analysis, as well as an accuracy gain compared to preliminary work on a small dataset.

  6. Systems and methods for controlling energy use during a demand limiting period

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, Michael J.; Drees, Kirk H.

    2016-04-26

    Systems and methods for limiting power consumption by a heating, ventilation, and air conditioning (HVAC) subsystem of a building are shown and described. A feedback controller is used to generate a manipulated variable based on an energy use setpoint and a measured energy use. The manipulated variable may be used for adjusting the operation of an HVAC device.

  7. Nitrate source apportionment using a combined dual isotope, chemical and bacterial property, and Bayesian model approach in river systems

    Science.gov (United States)

    Xia, Yongqiu; Li, Yuefei; Zhang, Xinyu; Yan, Xiaoyuan

    2017-01-01

    Nitrate (NO3-) pollution is a serious problem worldwide, particularly in countries with intensive agricultural and population activities. Previous studies have used δ15N-NO3- and δ18O-NO3- to determine the NO3- sources in rivers. However, this approach is subject to substantial uncertainties and limitations because of the numerous NO3- sources, the wide isotopic ranges, and the existing isotopic fractionations. In this study, we outline a combined procedure for improving the determination of NO3- sources in a paddy agriculture-urban gradient watershed in eastern China. First, the main sources of NO3- in the Qinhuai River were examined by the dual-isotope biplot approach, in which we narrowed the isotope ranges using site-specific isotopic results. Next, the bacterial groups and chemical properties of the river water were analyzed to verify these sources. Finally, we introduced a Bayesian model to apportion the spatiotemporal variations of the NO3- sources. Denitrification was first incorporated into the Bayesian model because denitrification plays an important role in the nitrogen pathway. The results showed that fertilizer contributed large amounts of NO3- to the surface water in traditional agricultural regions, whereas manure effluents were the dominant NO3- source in intensified agricultural regions, especially during the wet seasons. Sewage effluents were important in all three land uses and exhibited great differences between the dry season and the wet season. This combined analysis quantitatively delineates the proportion of NO3- sources from paddy agriculture to urban river water for both dry and wet seasons and incorporates isotopic fractionation and uncertainties in the source compositions.

  8. A compact and high sensitivity positron detector using dual-layer thin GSO scintillators for a small animal PET blood sampling system.

    Science.gov (United States)

    Yamamoto, Seiichi; Imaizumi, Masao; Shimosegawa, Eku; Kanai, Yasukazu; Sakamoto, Yusuke; Minato, Kotaro; Shimizu, Keiji; Senda, Michio; Hatazawa, Jun

    2010-07-07

    For quantitative measurements of small animals such as mice or rats, a compact and high sensitivity continuous blood sampling detector is required because their blood sampling volume is limited. For this purpose we have developed and tested a new positron detector. The positron detector uses a pair of dual-layer thin gadolinium orthosilicate (GSO) scintillators with different decay times. The front layer detects the positron and the background gamma photons, and the back layer detects the background gamma photons. By subtracting the count rate of the latter from that of the former, the count rate of the positrons can be estimated. The GSO for the front layer has a Ce concentration of 1.5 mol% (decay time of 35 ns), and that for the back layer has a Ce concentration of 0.5 mol% (decay time of 60 ns). By using the pulse shape analysis, the count rate of these two GSOs can be discriminated. The thickness is 0.5 mm, which is thick enough to detect positrons while minimizing the detection of the background gamma photons. These two types of thin GSOs were optically coupled to each other and connected to a metal photomultiplier tube (PMT) through triangular light guides. The signal from the PMT was digitized by 100 MHz free-running A-D converters in the data acquisition system and digitally integrated at two different integration times for the pulse shape analysis. We obtained good separation of the pulse shape distributions of these two GSOs. The energy threshold level was decreased to 80 keV, increasing the sensitivity of the detector. The sensitivity of a small diameter plastic tube was 8.6% and 24% for the F-18 and C-11 positrons, respectively. The count rate performance was linear up to approximately 50 kcps. The background counts from the gamma photons could be precisely corrected. The time-activity curve (TAC) of the rat artery blood was successfully obtained and showed a good correlation with that measured using a well counter. With these results, we confirmed

  9. Quality in dual-energy X-ray absorptiometry scans.

    Science.gov (United States)

    Morgan, Sarah L; Prater, Ginnie L

    2017-11-01

    Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Dual-Energy SPECT and the Development of Peptide p5+14 for Imaging Amyloidosis

    Directory of Open Access Journals (Sweden)

    Jonathan S. Wall PhD

    2017-05-01

    Full Text Available Amyloidosis is associated with a number of rare diseases and is characterized by the deposition, in abdominothoracic organs and peripheral nerves, of extracellular protein fibrils, which leads to dysfunction and severe morbidity. Effective clinical evaluation and management of patients with systemic amyloidosis are hampered by the lack of a noninvasive, quantitative method for detecting whole-body amyloid load. We have used a battery of assays including dual-energy SPECT imaging and comparative effectiveness studies in support of translation of a synthetic polybasic peptide, p5+14, as a novel radiotracer for visualization of amyloidosis by molecular imaging. These data provide support for a phase 1 positron emission tomography/computed tomography imaging trial of this reagent, labeled with iodine-124, in patients with all forms of systemic amyloidosis.

  11. Use of dual-energy CT and virtual non-calcium techniques to evaluate post-traumatic bone bruises in knees in the subacute setting

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Songtao [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Shanghai Ninth People' s Hospital, Department of Radiology, Shanghai (China); Qu, Mingliang; Glazebrook, Katrina N.; Liu, Yu; Leng, Shuai; McCollough, Cynthia H. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Rhee, Peter C. [Mayo Clinic, Department of Orthopedics, Rochester, MN (United States)

    2014-09-15

    The purpose of this study was to determine the ability of dual-energy computed tomography (DECT) and virtual non-calcium (VNCa) imaging to detect magnetic resonance imaging (MRI)-demonstrated bone bruises several weeks after unilateral knee injury. Patients with unilateral knee injury and MRI-confirmed bone bruises who had undergone a DECT scan of both knees were retrospectively identified. Two radiologists evaluated VNCa images for bruises in four regions per knee without knowing the MRI results. The mean CT numbers were calculated for the lesion-positive and lesion-negative regions of the injured knee, and the contralateral knee. Fourteen patients with a total of 36 regions positive for bone bruises on MRI were identified. The median delay between injury and DECT was 37 days (range, 11-99 days). The mean CT numbers in VNCa images for lesion-positive and lesion-negative regions were -7.6 ± 24.9 HU and -58.2 ± 19.5 HU, respectively. There were no significant differences in mean CT number between the lesion-negative regions in the injured knee and the contralateral knee. No resolution of bruising was seen before week 5, and bone bruising was still identifiable in one out of the two patients scanned at 10 weeks following injury. DECT and VNCa images can identify bone bruising for at least 10 weeks after injury. (orig.)

  12. Dual-channel and multifrequency radar system calibration

    Science.gov (United States)

    Stjernman, Anders; Vivekanandan, J.; Nystrom, Anders

    1995-03-01

    Uncertainty in absolute gain and crosstalk factors are the primary sources of error in dual-channel radar measurements. A full two-port calibration technique compensates for the errors introduced due to an imperfect antenna system and improves the isolation between orthogonal polarization channels as long as the observed cross section is above the equivalent system noise cross section. A novel technique for calibrating a dual-polarized network analyzer-based scatterometer system is discussed. Rigorous two-port S-parameter representation is used to describe absolute gain and crosstalk characteristics. Validity of the crosstalk correction is demonstrated by measuring the point target scattering matrix. Correction factors are obtained by measuring the S-parameters of trihedral and dihedral corner reflectors of known sizes. Results of absolute gain of the antenna system are verified using independent test target cross section measurements.

  13. On the Use of Energy Storage Technologies for Regulation Services in Electric Power Systems with Significant Penetration of Wind Energy

    DEFF Research Database (Denmark)

    Yang, Bo; Makarov, Yuri; Desteese, John

    2008-01-01

    Energy produced by intermittent renewable resources is sharply increasing in the United States. At high penetration levels, volatility of wind power production could cause additional problems for the power system balancing functions such as regulation. This paper reports some partial results...... of a project work, recently conducted by the Pacific Northwest National Laboratory (PNNL) for Bonneville Power Administration (BPA). The project proposes to mitigate additional intermittency with the help of Wide Area Energy Management System (WAEMS) that would provide a two-way simultaneous regulation service...... for the BPA and California ISO systems by using a large energy storage facility. The paper evaluates several utility-scale energy storage technology options for their usage as regulation resources. The regulation service requires a participating resource to quickly vary its power output following the rapidly...

  14. Concept for a user interface in the energy branch. For systems using renewable energy sources; Konzept fuer eine Rechenumgebung im Energiebereich. Fuer Systeme zur Nutzung regenerierbarer Energiequellen

    Energy Technology Data Exchange (ETDEWEB)

    Afjei, T. [INFEL, Zurich (Switzerland); Baumgartner, T. [Ing. Buero fuer Haustechnik, Duebendorf (Switzerland); Hopkirk, R.J. [POLYDYNAMICS LTD., Zurich (Switzerland); Kapp, C. [NEK Umwelttechnik, Zurich (Switzerland); Rognon, F. [Bundesamt fuer Energiewirtschaft, Bern (Switzerland)

    1994-09-15

    The report introduces the concept of a computing environment for software in the energy field, limited to systems which use regenerative energies. The target public consists of engineers, planners and energy consultants. A computing environment and a user surface which permit the modular integration of existing and new computing programmes are defined. figs., tabs., refs.

  15. Development of a differentially balanced magnetic bearing and control system for use with a flywheel energy storage system

    Science.gov (United States)

    Higgins, Mark A.; Plant, David P.; Ries, Douglas M.; Kirk, James A.; Anand, Davinder K.

    1992-01-01

    The purpose of a magnetically suspended flywheel energy storage system for electric utility load leveling is to provide a means to store energy during times when energy is inexpensive to produce and then return it to the customer during times of peak power demand when generated energy is most expensive. The design of a 20 kWh flywheel energy storage system for electric utility load leveling applications involves the successful integration of a number of advanced technologies so as to minimize the size and cost of the system without affecting its efficiency and reliability. The flywheel energy storage system uses a carbon epoxy flywheel, two specially designed low loss magnetic bearings, a high efficiency motor generator, and a 60 cycle AC power converter all integrated through a microprocessor controller. The basic design is discussed of each of the components that is used in the energy storage design.

  16. Dual $n_1$-Appell-like Systems in Infinite-Dimensional Analysis

    CERN Document Server

    Kachanovsky, N A

    1997-01-01

    We introduce and study dual $n_1$-Appell-like systems which are the simple generalization of generalized dual Appell systems in Infinite-Dimensional Analysis (IDA). We study connected with these systems objects of IDA: the analogues of Kondratiev spaces, $S$-transform, characterization theorems etc. The results we obtained are useful to application in the theory of probability.

  17. Small animals bone density and morphometry analysis with a dual energy X-rays absorptiometry bone densitometer using a 2D digital radiographic detector; Analyse de la densite osseuse et de la morphometrie de petits animaux avec un osteodensitometre bi-energie utilisant un capteur 2D de radiographie numerique

    Energy Technology Data Exchange (ETDEWEB)

    Boudousq, V. [Centre Hospitalier Universitaire de Nimes, 30 (France); Bordy, T.; Gonon, G.; Dinten, J.M. [CEA Grenoble (DTBS/STD), Lab. d' Electronique et de Technologie de l' Informatique, LETI, 38 (France)

    2004-07-01

    LEXXOS (DMS, Montpellier, France) is the first axial and total body cone beam bone densitometer using a 2D digital radiographic detector. In previous papers, technical principles and patients' Bone Mineral Density (BMD) measurement performances were presented. Bone densitometers are also used on small animals for drug development. In this presentation, we show how LEXXOS can be adapted for small animals' examinations and evaluate its performances. At first, in order to take advantage of the whole area of the 20 x 20 cm{sup 2} digital radiographic detector, it has been made profit of X-Rays magnification by adapting the geometrical configuration. Secondly, as small animals present low BMD, a specific dual energy calibration has been defined. This adapted system has then been evaluated on two sets of mice: six reference mice and six ovariectomized mice. Each month, these two populations have been examined and the averaged total body BMD has been measured. This evaluation shows that the right order of BMD magnitude is obtained and, as expected, BMD increases on two sets until a period around puberty and the ovariectomized set presents a significant decrease after. Moreover, the bone image obtained by dual energy processing on LEXXOS presents a radiographic image quality providing useful complementary information on bone morphometry and architecture. This study shows that LEXXOS cone beam bone densitometer provides simultaneously useful quantitative and qualitative information for analysis of bone evolution on small animals. In the future, same system architecture and processing methodology can be used with higher resolution detectors in order to refine information on bone architecture. (authors)

  18. Energy saving synergies in national energy systems

    DEFF Research Database (Denmark)

    Thellufsen, Jakob Zinck; Lund, Henrik

    2015-01-01

    In the transition towards a 100% renewable energy system, energy savings are essential. The possibility of energy savings through conservation or efficiency increases can be identified in, for instance, the heating and electricity sectors, in industry, and in transport. Several studies point...... to various optimal levels of savings in the different sectors of the energy system. However, these studies do not investigate the idea of energy savings being system dependent. This paper argues that such system dependency is critical to understand, as it does not make sense to analyse an energy saving...... without taking into account the actual benefit of the saving in relation to the energy system. The study therefore identifies a need to understand how saving methods may interact with each other and the system in which they are conducted. By using energy system analysis to do hourly simulation...

  19. Investigating the effects of Salvia mirzayanii essential oil on rumen microbial fermentation and nutrient digestibility using gas production and dual flow continuous culture system

    Directory of Open Access Journals (Sweden)

    Younes Ouladshanbe

    2014-08-01

    Full Text Available This study was conducted to investigate the effects of different doses of salvia mirzayanii essential oils on gas production parameters, fermentation characteristics using gas production and dual flow continuous culture system. Trearments in the gas production experiment was adding 0, 400, 800, 1200, 1600, 2000, 2400 and 4800 mg/l of salvia mirzayanii essential oils to the media. In the second experiment, five 1750-mL dual-flow continuous culture fermenters were used in 3 replicated periods of 9 d. Temperature (38.5°C and liquid and (10%/h solid (5%/h dilution rates were kept constant in the fermenters. Fermenters were fed daily with 120 g dry matter. Treatments arranged as complete randomized block design included levels of essential oils from salvia mirzayanii (800, 1600, 2400 mg/l and a monensin (0.1 percent of the diet dry matter. Addition essential oils of salvia mirzayanii to diet lead to decrease asymptotic gas production, organic matter degradability and biomass. Dry matter digestibility and NDF with the level of 800 mg/l essential oil compered to control treatment were significantly increased. Concentration of NH3-N was less for pre-feeding (0 h in treatments with T2 and T3 compared with control treatment. The average of concentration NH3-N was lowest in highest level of essential oils eight hours after feeding. The results showed that using of low level of salvia mirzayanii essential oils could improve nutrient digestibility in the rumen.

  20. Dual energy computed tomography quantification of carotid plaques calcification: comparison between monochromatic and polychromatic energies with pathology correlation

    Energy Technology Data Exchange (ETDEWEB)

    Mannelli, Lorenzo [University of Washington, Departments of Radiology, Seattle, WA (United States); Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY (United States); MacDonald, Lawrence; Ferguson, Marina; Shuman, William P.; Xu, Dongxiang; Yuan, Chun; Mitsumori, Lee M. [University of Washington, Departments of Radiology, Seattle, WA (United States); Mancini, Marcello; Ragucci, Monica; Monti, Serena [IRCCS Fondazione SDN, Naples (Italy)

    2015-05-01

    We compared carotid plaque calcification detection sensitivity and apparent cross-sectional area on CT as a function of CT beam energy using conventional CT techniques and virtual mono-energetic CT images generated from dual-energy acquisitions. Five ex-vivo carotid endarterectomy (CEA) specimens were imaged with dual-energy computed tomography. Virtual monochromatic spectrum (VMS) CT images were reconstructed at energies between 40-140 keV. The same specimens were imaged using conventional polyenergetic spectrum (PS) CT with peak beam energies 80, 100, 120, and 140 kVp. The histological calcium areas on each corresponding CEA specimen were traced manually on digitized images of Toluidine-Blue/Basic-Fuchsin stained plastic sections. 40 keV VMS CT images provided high detection sensitivity (97 %) similar to conventional PS CT images (∝96 %). The calcification size measured on CT decreased systematically with increasing CT beam energy; the rate of change was larger for the VMS images than for PS images. From a single dual-energy CT, multiple VMS-CT images can be generated, yielding equivalent detection sensitivity and size correlations as conventional PS-CT in CEA calcification imaging. VMS-CT at 80-100 keV provided the most accurate estimates of calcification size, as compared to histology, but detection sensitivity was reduced for smaller calcifications on these images. (orig.)

  1. A Study of Energy Optimisation of Urban Water Distribution Systems Using Potential Elements

    Directory of Open Access Journals (Sweden)

    Ioan Sarbu

    2016-12-01

    Full Text Available Energy use in water supply systems represents a significant portion of the global energy consumption. The electricity consumption due to the water pumping represents the highest proportion of the energy costs in these systems. This paper presents several comparative studies of energy efficiency in water distribution systems considering distinct configurations of the networks and also considers implementation of the variable-speed pumps. The main objective of this study is the energy optimisation of urban systems using optimal network configurations that reduce energy consumption and improve energy efficiency. The paper describes in detail four strategies for improving energy efficiency of water pumping: control systems to vary pump speed drive according to water demand, pumped storage tanks, intermediary pumping stations integrated in the network, and elevated storage tanks floating on the system. The improving energy efficiency of water pumping is briefly reviewed providing a representative real case study. In addition, a different approach for the hydraulic analysis of the networks and the determination of the optimal location of a pumped storage tank is provided. Finally, this study compares the results of the application of four water supply strategies to a real case in Romania. The results indicate high potential operating costs savings.

  2. Energy Usage Analysis System

    Data.gov (United States)

    General Services Administration — The EUAS application is a web based system which serves Energy Center of Expertise, under the Office of Facilitates Management and Service Programs. EUAS is used for...

  3. Detection of pulmonary fat embolism with dual-energy CT: an experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun Xiang; Zhou, Chang Sheng; Zhao, Yan E.; Han, Zong Hong; Qi, Li; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Mangold, Stefanie; Ball, B.D. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2017-04-15

    To evaluate the use of dual-energy CT imaging of the lung perfused blood volume (PBV) for the detection of pulmonary fat embolism (PFE). Dual-energy CT was performed in 24 rabbits before and 1 hour, 1 day, 4 days and 7 days after artificial induction of PFE via the right ear vein. CT pulmonary angiography (CTPA) and lung PBV images were evaluated by two radiologists, who recorded the presence, number, and location of PFE on a per-lobe basis. Sensitivity, specificity, and accuracy of CTPA and lung PBV for detecting PFE were calculated using histopathological evaluation as the reference standard. A total of 144 lung lobes in 24 rabbits were evaluated and 70 fat emboli were detected on histopathological analysis. The overall sensitivity, specificity and accuracy were 25.4 %, 98.6 %, and 62.5 % for CTPA, and 82.6 %, 76.0 %, and 79.2 % for lung PBV. Higher sensitivity (p < 0.001) and accuracy (p < 0.01), but lower specificity (p < 0.001), were found for lung PBV compared with CTPA. Dual-energy CT can detect PFE earlier than CTPA (all p < 0.01). Dual-energy CT provided higher sensitivity and accuracy in the detection of PFE as well as earlier detection compared with conventional CTPA in this animal model study. (orig.)

  4. Detection of pulmonary fat embolism with dual-energy CT: an experimental study in rabbits.

    Science.gov (United States)

    Tang, Chun Xiang; Zhou, Chang Sheng; Zhao, Yan E; Schoepf, U Joseph; Mangold, Stefanie; Ball, B Devon; Han, Zong Hong; Qi, Li; Zhang, Long Jiang; Lu, Guang Ming

    2017-04-01

    To evaluate the use of dual-energy CT imaging of the lung perfused blood volume (PBV) for the detection of pulmonary fat embolism (PFE). Dual-energy CT was performed in 24 rabbits before and 1 hour, 1 day, 4 days and 7 days after artificial induction of PFE via the right ear vein. CT pulmonary angiography (CTPA) and lung PBV images were evaluated by two radiologists, who recorded the presence, number, and location of PFE on a per-lobe basis. Sensitivity, specificity, and accuracy of CTPA and lung PBV for detecting PFE were calculated using histopathological evaluation as the reference standard. A total of 144 lung lobes in 24 rabbits were evaluated and 70 fat emboli were detected on histopathological analysis. The overall sensitivity, specificity and accuracy were 25.4 %, 98.6 %, and 62.5 % for CTPA, and 82.6 %, 76.0 %, and 79.2 % for lung PBV. Higher sensitivity (p PFE earlier than CTPA (all p PFE as well as earlier detection compared with conventional CTPA in this animal model study. • Fat embolism occurs commonly in patients with traumatic bone injury. • Dual-energy CT improves diagnostic performance for pulmonary fat embolism detection. • Dual-energy CT can detect pulmonary fat embolism earlier than CTPA.

  5. Feasibility Study of Energy Storage Systems in Wind/Diesel Applications Using the HOMER Model

    Directory of Open Access Journals (Sweden)

    Andrew Stiel

    2012-10-01

    Full Text Available With an increased focus on solutions to the ensuing “climate crisis”, the need for energy storage systems is becoming increasingly important as a means to increase the penetration of renewable technologies such as wind energy. The Vanadium Redox Battery is one such energy storage system showing considerable potential owing to its flexibility in power output and capacity, high efficiency and long operating life. This study models the use of the Vanadium Redox Battery as an integration technology in realistic large-scale remote wind/diesel power systems using the HOMER Micropower Optimization Model computer program developed by the US National Renewable Energy Laboratory. Results from this modelling demonstrate the significant financial and environmental benefits to be gained in installing energy storage in a wind farm. The storage system considered here was a Vanadium Redox Battery.

  6. Rechargeable dual-metal-ion batteries for advanced energy storage.

    Science.gov (United States)

    Yao, Hu-Rong; You, Ya; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

    2016-04-14

    Energy storage devices are more important today than any time before in human history due to the increasing demand for clean and sustainable energy. Rechargeable batteries are emerging as the most efficient energy storage technology for a wide range of portable devices, grids and electronic vehicles. Future generations of batteries are required to have high gravimetric and volumetric energy, high power density, low price, long cycle life, high safety and low self-discharge properties. However, it is quite challenging to achieve the above properties simultaneously in state-of-the-art single metal ion batteries (e.g. Li-ion batteries, Na-ion batteries and Mg-ion batteries). In this contribution, hybrid-ion batteries in which various metal ions simultaneously engage to store energy are shown to provide a new perspective towards advanced energy storage: by connecting the respective advantages of different metal ion batteries they have recently attracted widespread attention due to their novel performances. The properties of hybrid-ion batteries are not simply the superposition of the performances of single ion batteries. To enable a distinct description, we only focus on dual-metal-ion batteries in this article, for which the design and the benefits are briefly discussed. We enumerate some new results about dual-metal-ion batteries and demonstrate the mechanism for improving performance based on knowledge from the literature and experiments. Although the search for hybrid-ion batteries is still at an early age, we believe that this strategy would be an excellent choice for breaking the inherent disadvantages of single ion batteries in the near future.

  7. Dual-keel electrodynamic maglev system

    Energy Technology Data Exchange (ETDEWEB)

    He, Jianliang (Naperville, IL); Wang, Zian (Downers Grove, IL); Rote, Donald M. (Lagrange, IL); Coffey, Howard T. (Darien, IL); Hull, John R. (Westmont, IL); Mulcahy, Thomas M. (Western Springs, IL); Cal, Yigang (Woodridge, IL)

    1996-01-01

    A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.

  8. Optimal calibration via virtual x-ray imaging for dual-energy techniques: application to glass wool

    Science.gov (United States)

    Letang, Jean-Michel; Freud, N.; Peix, Gilles

    2003-04-01

    We present in this paper a technique that makes benefit of a virtual X-ray simulation tool to both assess the optimal spectra and calibrate a dual-energy technique. The proposed method is applied to the selective imaging of glass wool materials. To optimize the choice of energy spectra, a signal-to-noise (SNR) criterion on the materials estimated thickness is derived using a constant absorbed energy constraint in the detector. To study further its reliability, the criterion is related to the measurement quality, expressed by a contrast to noise ratio of the input projections, and to the inversion stability, expressed by a contrast to noise ration of the input projections, and to the inversion stability, expressed by the numerical conditioning of the linear dual-energy attenuation system. Once the choice of energy spectra is settled, apparent thicknesses are modeled as third order polynomials expressed in terms of X-ray attenuation measures. The best polynomial fit and the choice of the degree can again be advantageously assessed using virtual X-ray imaging. A semi-empirical catalog is here used to characterize the X-ray source spectrum, and attenuation coefficients for each corresponding compound substance are obtained from standard databases. After completion of those calibration phases, a glass wool phantom composed of PMMA and glass (combined step wedges) is used to validate using real experimental data the selected dual-energy protocol obtained by virtual X-ray imaging. The worse error on the estimated thickness is about 5% for both the binder and the glass fibers. Quantitative imaging in thickness of glass fibers and binder is finally presented.

  9. About accuracy of the discrimination parameter estimation for the dual high-energy method

    Science.gov (United States)

    Osipov, S. P.; Chakhlov, S. V.; Osipov, O. S.; Shtein, A. M.; Strugovtsev, D. V.

    2015-04-01

    A set of the mathematical formulas to estimate the accuracy of discrimination parameters for two implementations of the dual high energy method - by the effective atomic number and by the level lines is given. The hardware parameters which influenced on the accuracy of the discrimination parameters are stated. The recommendations to form the structure of the high energy X-ray radiation impulses are formulated. To prove the applicability of the proposed procedure there were calculated the statistical errors of the discrimination parameters for the cargo inspection system of the Tomsk polytechnic university on base of the portable betatron MIB-9. The comparison of the experimental estimations and the theoretical ones of the discrimination parameter errors was carried out. It proved the practical applicability of the algorithm to estimate the discrimination parameter errors for the dual high energy method.

  10. Design of dual DC motor control system based on DSP

    Science.gov (United States)

    Shi, Peicheng; Wang, Suo; Xu, Zengwei; Xiao, Ping

    2017-08-01

    Multi-motor control systems are widely used in actual production and life, such as lifting stages, robots, printing systems. This paper through serial communication between PC and DSP, dual DC motor control system consisting of PC as the host computer, DSP as the lower computer with synchronous PWM speed regulation, commutation and selection functions is designed. It sends digital control instructions with host computer serial debugger to lower computer, to instruct the motor to complete corresponding actions. The hardware and software design of the control system are given, and feasibility and validity of the control system are verified by experiments. The expected design goal is achieved.

  11. Forest Height Inversion Using Dual-pol Polarimetric SAR Interferometry

    Science.gov (United States)

    Fu, W. X.; Guo, H. D.; Xie, C.; Lu, Y. C.; Li, X. W.

    2014-03-01

    Polarimetric Synthetic Aperture Radar Interferometry (PolInSAR) has been extensively applied for forest parameter inversion over different frequencies and polarimetric conditions. So far, most research was based on full-pol SAR images with relatively small coverage. A spaceborne SAR system will have the potential for PolInSAR applications used for global forest monitoring. Spaceborne dual-pol SAR images usually have higher resolution and larger swath than full-pol mode. In this paper, forest height retrieval was attempted by PolInSAR from a L-band spaceborne dual-pol SAR pairs using HH and HV channels. The random volume over ground (RVoG) model was used to retrieve the height and the coherence optimization method was extended to the dual-pol PolInSAR, which makes use of polarimetry to enhance the quality of SAR interferograms. The three-stage process is also used in the dual-pol PolInSAR technique. Finally, the experimental test was performed for forest height estimation on the dual-pol L-band SAR data of the Saihanba forest acquired by the ALOS PALSAR sensor in 2009.

  12. Linking the dual system with higher education in Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Christian Helms

    2013-01-01

    As more than half of every new generation of youth enter higher education in Den-mark the strength of the dual system of vocational education is becoming its weakness. Completing a programme in the dual system doesn’t give access to higher ed-ucation, and the system is increasingly seen as a ‘blind...

  13. CT dual-energy decomposition into x-ray signatures ρe and Ze

    Science.gov (United States)

    Martz, Harry E.; Seetho, Issac M.; Champley, Kyle E.; Smith, Jerel A.; Azevedo, Stephen G.

    2016-05-01

    In a recent journal article [IEEE Trans. Nuc. Sci., 63(1), 341-350, 2016], we introduced a novel method that decomposes dual-energy X-ray CT (DECT) data into electron density (ρe) and a new effective-atomic-number called Ze in pursuit of system-independent characterization of materials. The Ze of a material, unlike the traditional Zeff, is defined relative to the actual X-ray absorption properties of the constituent atoms in the material, which are based on published X-ray cross sections. Our DECT method, called SIRZ (System-Independent ρe, Ze), uses a set of well-known reference materials and an understanding of the system spectral response to produce accurate and precise estimates of the X-ray-relevant basis variables (ρe, Ze) regardless of scanner or spectra in diagnostic energy ranges (30 to 200 keV). Potentially, SIRZ can account for and correct spectral changes in a scanner over time and, because the system spectral response is included in the technique, additional beam-hardening correction is not needed. Results show accuracy (<3%) and precision (<2%) values that are much better than prior methods on a wide range of spectra. In this paper, we will describe how to convert DECT system output into (ρe, Ze) features and we present our latest SIRZ results compared with ground truth for a set of materials.

  14. Dual systems of speech category learning across the lifespan

    Science.gov (United States)

    Maddox, W. Todd; Chandrasekaran, Bharath; Smayda, Kirsten; Yi, Han-Gyol

    2013-01-01

    Although categorization is fundamental to speech processing, little is known about the learning systems that mediate auditory categorization and even less is known about changes across the lifespan. Vision research supports dual-learning systems that are grounded in neuroscience and are partially-dissociable. The reflective, rule-based system is prefrontally mediated and uses working memory and executive attention to develop and test rules for classifying in an explicit fashion. The reflexive, information-integration system is striatally mediated and operates by implicitly associating perception with actions that lead to reinforcement. We examine the extent to which dual-learning systems mediate auditory and speech learning in younger and older adults. We examined auditory category learning when a rule-based strategy (Experiment 1) or information-integration strategy (Experiment 2) was optimal, and found an age-related rule-based deficit, but intact information-integration learning. Experiment 3 examined natural auditory category learning, and found an age-related performance deficit. Computational modeling suggested that this was due to older adults’ persistent reliance on sub-optimal, uni-dimensional strategies when two-dimensional strategies were optimal. Working memory capacity was also found to be associated with improved rule-based and natural auditory category learning, but not information-integration category learning. These results suggest that dual-learning systems are operative in speech category learning across the lifespan, and that performance deficits, when present are due to deficiencies in frontally-mediated, rule-based processes. PMID:24364408

  15. TESTING OF THE DUAL ROTARY FILTER SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D.; Fowley, M.; Stefanko, D.

    2011-08-29

    The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

  16. A Design Study Of A Wireless Power Transfer System For Use To Transfer Energy From A Vibration Energy Harvester

    Science.gov (United States)

    Grabham, N. J.; Harden, C.; Vincent, D.; Beeby, S. P.

    2016-11-01

    A wirelessly powered remote sensor node is presented along with its design process. The purpose of the node is the further expansion of the sensing capabilities of the commercial Perpetuum system used for condition monitoring on trains and rolling stock which operates using vibration energy harvesting. Surplus harvested vibration energy is transferred wirelessly to a remote satellite sensor to allow measurements over a wider area to be made. This additional data is to be used for long term condition monitoring. Performance measurements made on the prototype remote sensor node are reported and advantages and disadvantages of using the same RF frequency for power and data transfer are identified.

  17. P50/P90 Analysis for Solar Energy Systems Using the System Advisor Model: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dobos, A. P.; Gilman, P.; Kasberg, M.

    2012-06-01

    To secure competitive financing for a solar energy generation project, the economic risk associated with interannual solar resource variability must be quantified. One way to quantify this risk is to calculate exceedance probabilities representing the amount of energy expected to be produced by a plant. Many years of solar radiation and metereological data are required to determine these values, often called P50 or P90 values for the level of certainty they represent. This paper describes the two methods implemented in the National Renewable Energy Laboratory's System Advisor Model (SAM) to calculate P50 and P90 exceedance probabilities for solar energy projects. The methodology and supporting data sets are applicable to photovoltaic, solar water heating, and concentrating solar power (CSP) systems.

  18. Smoothing of wind farm output power using prediction based flywheel energy storage system

    Science.gov (United States)

    Islam, Farzana

    Being socially beneficial, economically competitive and environment friendly, wind energy is now considered to be the world's fastest growing renewable energy source. However, the stochastic nature of wind imposes a considerable challenge in the optimal management and operation of wind power system. Wind speed prediction is critical for wind energy conversion system since it greatly influences the issues related to effective energy management, dynamic control of wind turbine, and improvement of the overall efficiency of the power generation system. This thesis focuses on integration of energy storage system with wind farm, considering wind speed prediction in the control scheme to overcome the problems associated with wind power fluctuations. In this thesis, flywheel energy storage system (FESS) with adjustable speed rotary machine has been considered for smoothing of output power in a wind farm composed of a fixed speed wind turbine generator (FSWTG). Since FESS has both active and reactive power compensation ability, it enhances the stability of the system effectively. An efficient energy management system combined with supervisory control unit (SCU) for FESS and wind speed prediction has been developed to improve the smoothing of the wind farm output effectively. Wind speed prediction model is developed by artificial neural network (ANN) which has advantages over the conventional prediction scheme including data error tolerance and ease in adaptability. The model for prediction with ANN is developed in MATLAB/Simulink and interfaced with PSCAD/EMTDC. Effectiveness of the proposed control system is illustrated using real wind speed data in various operating conditions.

  19. Managing dual use technology: it takes two to tango.

    Science.gov (United States)

    Kant, Lalit; Mourya, D T

    2010-03-01

    Like nuclear energy, most technologies could have dual use-for health and well being and disaster and terror. Some research publications have brought to the forefront the tragic consequences of the latter potential through their possible use. Monitoring life science research and development (R&D) to prevent possible misuse is a challenging task globally, more so in developing economies like India, which are emerging as major biotech hubs. As a signatory to the Biological and Toxin Weapons Convention, India has put in motion a process of evolving a series of measures to manage dual-use technology. The Indian Council of Medical Research (ICMR) has taken a lead in drafting model codes of conduct, ethics and practice for use by other S&T agencies to tailor them as per their requirements. Taking cue from the discussions held by the editors of the various medical and science journals in the developed world, the Indian Journal of Medical Research, the official publication of the ICMR, is working on policy and uniform practice of publication of dual-use research results. The Government of India too has promulgated legal provisions to minimize the risks of misuse of technology, like the Weapons of Mass Destruction Act. Clearly, no single agency would be able to manage the dual-use of technology effectively. Multiple agencies have to come together to work in tandem for effective implementation of various measure and also like Janus, ensure that they are neither too restrictive nor intrusive to discourage the development of science.

  20. Hybrid energy harvesting using active thermal backplane

    Science.gov (United States)

    Kim, Hyun-Wook; Lee, Dong-Gun

    2016-04-01

    In this study, we demonstrate the concept of a new hybrid energy harvesting system by combing solar cells with magneto-thermoelectric generator (MTG, i.e., thermal energy harvesting). The silicon solar cell can easily reach high temperature under normal operating conditions. Thus the heated solar cell becomes rapidly less efficient as the temperature of solar cell rises. To increase the efficiency of the solar cell, air or water-based cooling system is used. To surpass conventional cooling devices requiring additional power as well as large working space for air/water collectors, we develop a new technology of pairing an active thermal backplane (ATB) to solar cell. The ATB design is based on MTG technology utilizing the physics of the 2nd order phase transition of active ferromagnetic materials. The MTG is cost-effective conversion of thermal energy to electrical energy and is fundamentally different from Seebeck TEG devices. The ATB (MTG) is in addition to being an energy conversion system, a very good conveyor of heat through both conduction and convection. Therefore, the ATB can provide dual-mode for the proposed hybrid energy harvesting. One is active convective and conductive cooling for heated solar cell. Another is active thermal energy harvesting from heat of solar cell. These novel hybrid energy harvesting device have potentially simultaneous energy conversion capability of solar and thermal energy into electricity. The results presented can be used for better understanding of hybrid energy harvesting system that can be integrated into commercial applications.

  1. Energy use efficiency and greenhouse gas emissions of farming systems in north Iran

    NARCIS (Netherlands)

    Mohammadi, Ali; Rafiee, Shahin; Jafari, Ali; Keyhani, Alireza; Mousavi-Avval, Seyed Hashem; Nonhebel, Sanderine

    2014-01-01

    Efficient use of energy resources in crop production is an important goal in sustainable agriculture. This study compares the energy flow in farming systems across farm size with their corresponding greenhouse gas (GHG) emissions - presented in terms of carbon dioxide equivalent (CO2 eq.) - in the n

  2. Stochastic image reconstruction for a dual-particle imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, M.C., E-mail: mchamel@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Polack, J.K., E-mail: kpolack@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Poitrasson-Rivière, A., E-mail: alexispr@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Flaska, M., E-mail: mflaska@psu.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Department of Mechanical and Nuclear Engineering, Pennsylvania State University, 137 Reber Building, University Park, PA 16802 (United States); Clarke, S.D., E-mail: clarkesd@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Pozzi, S.A., E-mail: pozzisa@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109 (United States); Tomanin, A., E-mail: alice.tomanin@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, 21027 Ispra, VA (Italy); Lainsa-Italia S.R.L., via E. Fermi 2749, 21027 Ispra, VA (Italy); Peerani, P., E-mail: paolo.peerani@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, 21027 Ispra, VA (Italy)

    2016-02-21

    Stochastic image reconstruction has been applied to a dual-particle imaging system being designed for nuclear safeguards applications. The dual-particle imager (DPI) is a combined Compton-scatter and neutron-scatter camera capable of producing separate neutron and photon images. The stochastic origin ensembles (SOE) method was investigated as an imaging method for the DPI because only a minimal estimation of system response is required to produce images with quality that is comparable to common maximum-likelihood methods. This work contains neutron and photon SOE image reconstructions for a {sup 252}Cf point source, two mixed-oxide (MOX) fuel canisters representing point sources, and the MOX fuel canisters representing a distributed source. Simulation of the DPI using MCNPX-PoliMi is validated by comparison of simulated and measured results. Because image quality is dependent on the number of counts and iterations used, the relationship between these quantities is investigated.

  3. Specific survivin dual fluorescence resonance energy transfer molecular beacons for detection of human bladder cancer cells

    Institute of Scientific and Technical Information of China (English)

    Zhi-qiang WANG; Jun ZHAO; Jin ZENG; Kai-jie WU; Yu-le CHEN; Xin-ya ng WANG; Luke S CHANG; Da-lin HE

    2011-01-01

    Survivin molecular beacons can be used to detectbladder cancer cells in urine samples non-invasively.The aim of this study is to improve the specificity of detection of bladder cancer cells using survivin dual fluorescence resonance energy transfer molecular beacons (FRET MBs) that have fluorophores forming one donor-acceptor pair.Methods:Survivin-targeting dual fluorescence resonance energy transfer molecular beacons with unique target sequences were designed,which had no overlap with the other genes in the apoptosis inhibitor protein family.Human bladder cancer cell lines 5637,253J and T24,as well as the exfoliated cells in the urine of healthy adults and patients with bladder cancer were examined.Images of cells were taken using a laser scanning confocal fluorescence microscope.For assays using dual FRET MBs,the excitation wavelength was 488 nm,and the emission detection wavelengths were 520+20 nm and 560+20 nm,respectively.Results:The human bladder cancer cell lines and exfoliated cells in the urine of patients with bladder cancer incubated with the survivin dual FRET MBs exhibited strong fluorescence signals.In contrast,no fluorescence was detected in the survivin-negative human dermal fibroblasts-adult (HDF-a) cells or exfoliated cells in the urine of healthy adults incubated with the survivin dual FRET MBs.Conclusion:The results suggest that the survivin dual FRET MBs may be used as a specific and non-invasive method for early detection and follow-up of patients with bladder cancer.

  4. Utility of iodine overlay technique and virtual unenhanced images for the characterization of renal masses by dual-energy CT.

    Science.gov (United States)

    Song, Kyoung Doo; Kim, Chan Kyo; Park, Byung Kwan; Kim, Bohyun

    2011-12-01

    The objective of our study was to assess the utility of dual-energy CT for characterizing renal masses using iodine overlay techniques and virtual unenhanced images and to measure the potential radiation dose reduction for two-phase kidney CT compared with a standard three-phase protocol. Sixty patients with suspected renal masses underwent dual-energy CT including true unenhanced, dual-energy corticomedullary, and dual-energy late nephrographic phase imaging. Iodine overlay and virtual unenhanced images were derived from the corticomedullary and late nephrographic phases, respectively. The CT numbers of renal masses were calculated using the iodine overlay images superimposed on the virtual unenhanced images. The overall imaging quality of the true unenhanced images and of the virtual unenhanced images was also evaluated. The effective radiation doses for dual-energy CT and for true unenhanced imaging were calculated. For overlay or enhancement values on iodine overlay images, 36 simple cysts and 10 hemorrhagic cysts had an attenuation value of less than 20 HU, whereas 21 renal cell carcinomas showed an attenuation value of 20 HU or greater. Eleven angiomyolipomas contained macroscopic fat tissue. All renal masses were accurately classified on the basis of dual-energy CT. The imaging quality of the virtual unenhanced images from the corticomedullary and late nephrographic phases was inferior to the image quality of the true unenhanced images (p overlay techniques and virtual unenhanced images may be useful for characterizing renal masses.

  5. Dual-color reporter switching system to discern dimer formations of G-protein-coupled receptors using Cre/loxP site-specific recombination in yeast.

    Science.gov (United States)

    Nakamura, Yasuyuki; Hashimoto, Takamichi; Ishii, Jun; Kondo, Akihiko

    2016-10-01

    G-protein-coupled receptors (GPCRs) are physiologically important membrane proteins that represent major molecular targets in pharmaceutical and medicinal fields. Many GPCRs have been shown to form not only homodimers, but also heterodimers that can confer large functional and physiological diversity and are therefore expected to offer new opportunities for the discovery of new drugs. Yeast is a useful host organism that can be used to investigate the interactions between eukaryotic protein pairs, as demonstrated by the yeast two-hybrid (Y2H) system. Previously, we established reporter gene assay systems to screen for GPCR dimer pairs based on the split-ubiquitin membrane Y2H (mY2H) system. However, conventional systems only induce reporter gene expressions from the OFF to ON states. In this study, we therefore designed a reporter switching system that can switch the expressions between two reporter genes (one from ON to OFF and the other from OFF to ON) in response to the Y2H readout. To invoke reporter switching, we took advantage of Cre/loxP site-specific recombination. Through optimization of Cre-mediated reporter gene recombination using the split-ubiquitin mY2H system, we built a dual-color reporter switching system to discern the formations of GPCR dimers. This system enabled monitoring of the formations of homodimers and heterodimers of human serotonin 1A receptor or β2 -adrenergic receptor as well as homodimers of the yeast endogenous pheromone receptor (Ste2p) in yeast cells. Our reporter switching system may be a useful tool for identifying potential molecular targets among GPCR dimers, and is also applicable to other reporter gene assay systems. Biotechnol. Bioeng. 2016;113: 2178-2190. © 2016 Wiley Periodicals, Inc.

  6. Performance of the HIMAC beam control system using multiple-energy synchrotron operation

    Science.gov (United States)

    Mizushima, K.; Furukawa, T.; Iwata, Y.; Hara, Y.; Saotome, N.; Saraya, Y.; Tansho, R.; Sato, S.; Fujimoto, T.; Shirai, T.; Noda, K.

    2017-09-01

    Multiple-energy synchrotron operation was developed to realize fast 3D scanning irradiation for carbon-ion radiotherapy. This type of operation can output various carbon-ion beams with different energies in a single synchrotron cycle. The beam control system used in this kind of operation was developed to quickly provide the beam energy and intensity required from the irradiation control system. The performance of the system was verified by experimental tests. The system could output beams of 197 different energies in 63 s. The beam intensity could be controlled for all the output beams without large ripples or overshooting. The experimental test of irradiation for prostate cancer treatment was also successfully performed, and the test results proved that our system can greatly reduce the irradiation time.

  7. Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components

    Science.gov (United States)

    Malkov, Serghei; Shepherd, John

    2014-02-01

    We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed.

  8. Energy use and economical analysis of seedy watermelon production for different irrigation systems in Iran

    Directory of Open Access Journals (Sweden)

    Rooholla Moradi

    2015-11-01

    Full Text Available Resource and energy use efficiency is one of the principal requirements of eco-efficient and sustainable agriculture. Seedy watermelon (Citrullus vulgaris; Joboni population is irrigated by two methods including full and reduced irrigation systems in Iran. The objective of the present study was to compare seedy watermelon production in full (high input and reduced (low input irrigation systems in terms of irrigation water energy use efficiency (IWEUE, energy budget and economic analysis. Data were collected from 116 full irrigated and 93 reduced irrigated farms in northeast of Iran by using a face-to-face questionnaire in 2011–2012. The results showed that the total energy consumed under high input systems was 25625.94 MJ ha−1, whereas under low input was 3129.3 MJ ha−1. IWEUE and all of the energy indexes were improved in the reduced irrigation system compared to the full condition. The direct and renewable energies in the reduced irrigation system were higher than full irrigation. The economical analysis indicated that higher return was gained by the full irrigation system due to higher yield compared to the reduced irrigation system. Human labor had the highest impact on seedy watermelon among the other inputs based on the Cobb–Douglas production function.

  9. A highly efficient photosynthesis system using LCD technology for solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, Kenji [Research Inst. for Innovative Technology for the Earth (RITE), Kyoto (Japan); Nakano, Yoshihisa [Osaka Prefecture Univ., Coll. of Agriculture, Osaka (Japan)

    1999-07-01

    For CO{sub 2} fixation and utilisation, a newly developed culture combining a light conduction plate of Liquid Crystal Display (LCD) technology worked well. The injected light energy was effectively served to the whole area into the culture without mechanical energy such as stirring the fluid and the light energy efficiency of this system was obtained up to 60% of the theoretical value of 8 mol photons / 1 mol CO{sub 2}. The photosynthesis of the plant-like micro-organism, euglena glacilis, was used with solar energy. The product was useful for feed and will be for foods and fuels. (Author)

  10. FEMAN: Fuzzy-Based Energy Management System for Green Houses Using Hybrid Grid Solar Power

    Directory of Open Access Journals (Sweden)

    Abdellah Chehri

    2013-01-01

    Full Te