Science.gov

Sample records for boost field technique

  1. Ultrarelativistic boost with scalar field

    NASA Astrophysics Data System (ADS)

    Svítek, O.; Tahamtan, T.

    2016-02-01

    We present the ultrarelativistic boost of the general global monopole solution which is parametrized by mass and deficit solid angle. The problem is addressed from two different perspectives. In the first one the primary object for performing the boost is the metric tensor while in the second one the energy momentum tensor is used. Since the solution is sourced by a triplet of scalar fields that effectively vanish in the boosting limit we investigate the behavior of a scalar field in a simpler setup. Namely, we perform the boosting study of the spherically symmetric solution with a free scalar field given by Janis, Newman and Winicour. The scalar field is again vanishing in the limit pointing to a broader pattern of scalar field behaviour during an ultrarelativistic boost in highly symmetric situations.

  2. An imaging evaluation of the simultaneously integrated boost breast radiotherapy technique

    SciTech Connect

    Turley, Jessica; Claridge Mackonis, Elizabeth

    2015-09-15

    To evaluate in-field megavoltage (MV) imaging of simultaneously integrated boost (SIB) breast fields to determine its feasibility in treatment verification for the SIB breast radiotherapy technique, and to assess whether the current-imaging protocol and treatment margins are sufficient. For nine patients undergoing SIB breast radiotherapy, in-field MV images of the SIB fields were acquired on days that regular treatment verification imaging was performed. The in-field images were matched offline according to the scar wire on digitally reconstructed radiographs. The offline image correction results were then applied to a margin recipe formula to calculate safe margins that account for random and systematic uncertainties in the position of the boost volume when an offline correction protocol has been applied. After offline assessment of the acquired images, 96% were within the tolerance set in the current department-imaging protocol. Retrospectively performing the maximum position deviations on the Eclipse™ treatment planning system demonstrated that the clinical target volume (CTV) boost received a minimum dose difference of 0.4% and a maximum dose difference of 1.4% less than planned. Furthermore, applying our results to the Van Herk margin formula to ensure that 90% of patients receive 95% of the prescribed dose, the calculated CTV margins were comparable to the current departmental procedure used. Based on the in-field boost images acquired and the feasible application of these results to the margin formula the current CTV-planning target volume margins used are appropriate for the accurate treatment of the SIB boost volume without additional imaging.

  3. Esophageal Cancer Dose Escalation Using a Simultaneous Integrated Boost Technique

    SciTech Connect

    Welsh, James; Palmer, Matthew B.; Ajani, Jaffer A.; Liao Zhongxing; Swisher, Steven G.; Hofstetter, Wayne L.; Allen, Pamela K.; Settle, Steven H.; Gomez, Daniel; Likhacheva, Anna; Cox, James D.; Komaki, Ritsuko

    2012-01-01

    Purpose: We previously showed that 75% of radiation therapy (RT) failures in patients with unresectable esophageal cancer are in the gross tumor volume (GTV). We performed a planning study to evaluate if a simultaneous integrated boost (SIB) technique could selectively deliver a boost dose of radiation to the GTV in patients with esophageal cancer. Methods and Materials: Treatment plans were generated using four different approaches (two-dimensional conformal radiotherapy [2D-CRT] to 50.4 Gy, 2D-CRT to 64.8 Gy, intensity-modulated RT [IMRT] to 50.4 Gy, and SIB-IMRT to 64.8 Gy) and optimized for 10 patients with distal esophageal cancer. All plans were constructed to deliver the target dose in 28 fractions using heterogeneity corrections. Isodose distributions were evaluated for target coverage and normal tissue exposure. Results: The 50.4 Gy IMRT plan was associated with significant reductions in mean cardiac, pulmonary, and hepatic doses relative to the 50.4 Gy 2D-CRT plan. The 64.8 Gy SIB-IMRT plan produced a 28% increase in GTV dose and comparable normal tissue doses as the 50.4 Gy IMRT plan; compared with the 50.4 Gy 2D-CRT plan, the 64.8 Gy SIB-IMRT produced significant dose reductions to all critical structures (heart, lung, liver, and spinal cord). Conclusions: The use of SIB-IMRT allowed us to selectively increase the dose to the GTV, the area at highest risk of failure, while simultaneously reducing the dose to the normal heart, lung, and liver. Clinical implications warrant systematic evaluation.

  4. Comparison of Traditional and Simultaneous IMRT Boost Technique Basing on Therapeutic Gain Calculation

    SciTech Connect

    Slosarek, Krzysztof; Zajusz, Aleksander; Szlag, Marta

    2008-01-01

    Two different radiotherapy techniques, a traditional one (CRT) - based on consecutive decreasing of irradiation fields during treatment, and intensity modulated radiation therapy technique (IMRT) with concomitant boost, deliver different doses to treated volumes, increasing the dose in regions of interest. The fractionation schedule differs depending on the applied technique of irradiation. The aim of this study was to compare different fractionation schedules considering tumor control and normal tissue complications. The analysis of tumor control probability (TCP) and normal tissue complication probability (NTCP) were based on the linear quadratic (LQ) model of biologically equivalent dose. A therapeutic gain (TG) formula that combines NTCP and TCP for selected irradiated volumes was introduced to compare CRT and simultaneous boost (SIB) methods. TG refers to the different doses per fraction, overall treatment time (OTT), and selected biological factors such as tumor cell and repopulation time. Therapeutic gain increases with the dose per fraction and reaches the maximum for the doses at about 3 Gy. Further increase in dose per fraction results in decrease of TG, mainly because of the escalation of NTCP. The presented TG formula allows the optimization of radiotherapy planning by comparing different treatment plans for individual patients and by selecting optimal fraction dose.

  5. Three-Dimensional Conformal Simultaneously Integrated Boost Technique for Breast-Conserving Radiotherapy

    SciTech Connect

    Laan, Hans Paul van der

    2007-07-15

    Purpose: To compare the target coverage and normal tissue dose with the simultaneously integrated boost (SIB) and the sequential boost technique in breast cancer, and to evaluate the incidence of acute skin toxicity in patients treated with the SIB technique. Methods and Materials: Thirty patients with early-stage left-sided breast cancer underwent breast-conserving radiotherapy using the SIB technique. The breast and boost planning target volumes (PTVs) were treated simultaneously (i.e., for each fraction, the breast and boost PTVs received 1.81 Gy and 2.3 Gy, respectively). Three-dimensional conformal beams with wedges were shaped and weighted using forward planning. Dose-volume histograms of the PTVs and organs at risk with the SIB technique, 28 x (1.81 + 0.49 Gy), were compared with those for the sequential boost technique, 25 x 2 Gy + 8 x 2 Gy. Acute skin toxicity was evaluated for 90 patients treated with the SIB technique according to Common Terminology Criteria for Adverse Events, version 3.0. Results: PTV coverage was adequate with both techniques. With SIB, more efficiently shaped boost beams resulted in smaller irradiated volumes. The mean volume receiving {>=}107% of the breast dose was reduced by 20%, the mean volume outside the boost PTV receiving {>=}95% of the boost dose was reduced by 54%, and the mean heart and lung dose were reduced by 10%. Of the evaluated patients, 32.2% had Grade 2 or worse toxicity. Conclusion: The SIB technique is proposed for standard use in breast-conserving radiotherapy because of its dose-limiting capabilities, easy implementation, reduced number of treatment fractions, and relatively low incidence of acute skin toxicity.

  6. Usefulness of effective field theory for boosted Higgs production

    SciTech Connect

    Dawson, S.; Lewis, I. M.; Zeng, Mao

    2015-04-07

    The Higgs + jet channel at the LHC is sensitive to the effects of new physics both in the total rate and in the transverse momentum distribution at high pT. We examine the production process using an effective field theory (EFT) language and discussing the possibility of determining the nature of the underlying high-scale physics from boosted Higgs production. The effects of heavy color triplet scalars and top partner fermions with TeV scale masses are considered as examples and Higgs-gluon couplings of dimension-5 and dimension-7 are included in the EFT. As a byproduct of our study, we examine the region of validity of the EFT. Dimension-7 contributions in realistic new physics models give effects in the high pT tail of the Higgs signal which are so tiny that they are likely to be unobservable.

  7. Lorentz boosted frame simulation technique in Particle-in-cell methods

    NASA Astrophysics Data System (ADS)

    Yu, Peicheng

    /Finite Difference solver. This scheme also requires a current correction and filtering which require FFTs. However, we show that in this case the FFTs can be done locally on each parallel partition. We also describe how the use of the hybrid FFT/Finite Difference or the hybrid higher order finite difference/second order finite difference methods permit combining the Lorentz boosted frame simulation technique with another "speed up" technique, called the quasi-3D algorithm, to gain unprecedented speed up for the LWFA simulations. In the quasi-3D algorithm the fields and currents are defined on an r--z PIC grid and expanded in azimuthal harmonics. The expansion is truncated with only a few modes so it has similar computational needs of a 2D r--z PIC code. We show that NCI has similar properties in r--z as in z-x slab geometry and show that the same strategies for eliminating the NCI in Cartesian geometry can be effective for the quasi-3D algorithm leading to the possibility of unprecedented speed up. We also describe a new code called UPIC-EMMA that is based on fully spectral (FFT) solver. The new code includes implementation of a moving antenna that can launch lasers in the boosted frame. We also describe how the new hybrid algorithms were implemented into OSIRIS. Examples of LWFA using the boosted frame using both UPIC-EMMA and OSIRIS are given, including the comparisons against the lab frame results. We also describe how to efficiently obtain the boosted frame simulations data that are needed to generate the transformed lab frame data, as well as how to use a moving window in the boosted frame. The NCI is also a major issue for modeling relativistic shocks with PIC algorithm. In relativistic shock simulations two counter-propagating plasmas drifting at relativistic speeds are colliding against each other. We show that the strategies for eliminating the NCI developed in this dissertation are enabling such simulations being run for much longer simulation times, which should open a

  8. Lorentz boosted frame simulation technique in Particle-in-cell methods

    NASA Astrophysics Data System (ADS)

    Yu, Peicheng

    /Finite Difference solver. This scheme also requires a current correction and filtering which require FFTs. However, we show that in this case the FFTs can be done locally on each parallel partition. We also describe how the use of the hybrid FFT/Finite Difference or the hybrid higher order finite difference/second order finite difference methods permit combining the Lorentz boosted frame simulation technique with another "speed up" technique, called the quasi-3D algorithm, to gain unprecedented speed up for the LWFA simulations. In the quasi-3D algorithm the fields and currents are defined on an r--z PIC grid and expanded in azimuthal harmonics. The expansion is truncated with only a few modes so it has similar computational needs of a 2D r--z PIC code. We show that NCI has similar properties in r--z as in z-x slab geometry and show that the same strategies for eliminating the NCI in Cartesian geometry can be effective for the quasi-3D algorithm leading to the possibility of unprecedented speed up. We also describe a new code called UPIC-EMMA that is based on fully spectral (FFT) solver. The new code includes implementation of a moving antenna that can launch lasers in the boosted frame. We also describe how the new hybrid algorithms were implemented into OSIRIS. Examples of LWFA using the boosted frame using both UPIC-EMMA and OSIRIS are given, including the comparisons against the lab frame results. We also describe how to efficiently obtain the boosted frame simulations data that are needed to generate the transformed lab frame data, as well as how to use a moving window in the boosted frame. The NCI is also a major issue for modeling relativistic shocks with PIC algorithm. In relativistic shock simulations two counter-propagating plasmas drifting at relativistic speeds are colliding against each other. We show that the strategies for eliminating the NCI developed in this dissertation are enabling such simulations being run for much longer simulation times, which should open a

  9. Planning the Breast Boost: Comparison of Three Techniques and Evolution of Tumor Bed During Treatment

    SciTech Connect

    Hepel, Jaroslaw T. Evans, Suzanne B.; Hiatt, Jessica R.; Price, Lori Lyn; DiPetrillo, Thomas; Wazer, David E.; MacAusland, Stephanie G.

    2009-06-01

    Purpose: To evaluate the accuracy of two clinical techniques for electron boost planning compared with computed tomography (CT)-based planning. Additionally, we evaluated the tumor bed characteristics at whole breast planning and boost planning. Methods and Materials: A total of 30 women underwent tumor bed boost planning within 2 weeks of completing whole breast radiotherapy using three planning techniques: scar-based planning, palpation/clinical-based planning, and CT-based planning. The plans were analyzed for dosimetric coverage of the CT-delineated tumor bed. The cavity visualization score was used to define the CT-delineated tumor bed as well or poorly defined. Results: Scar-based planning resulted in inferior tumor bed coverage compared with CT-based planning, with the minimal dose received by 90% of the target volume >90% in 53% and a geographic miss in 53%. The results of palpation/clinical-based planning were significantly better: 87% and 10% for the minimal dose received by 90% of the target volume >90% and geographic miss, respectively. Of the 30 tumor beds, 16 were poorly defined by the cavity visualization score. Of these 16, 8 were well demarcated by the surgical clips. The evaluation of the 22 well-defined tumor beds revealed similar results. A comparison of the tumor bed volume from the initial planning CT scan to the boost planning CT scan revealed a decrease in size in 77% of cases. The mean decrease in volume was 52%. Conclusion: The results of our study have shown that CT-based planning allows for optimal tumor bed coverage compared with clinical and scar-based approaches. However, in the setting of a poorly visualized cavity on CT without surgical clips, palpation/clinical-based planning can help delineate the appropriate target volumes and is superior to scar-based planning. CT simulation at boost planning could allow for a reduction in the boost volumes.

  10. A cosmetic evaluation of breast cancer treatment: A randomized study of radiotherapy boost technique

    SciTech Connect

    Vass, Sylvie . E-mail: sylvie.vass@ssss.gouv.qc.ca; Bairati, Isabelle

    2005-08-01

    Purpose: To compare cosmetic results of two different radiotherapy (RT) boost techniques used in the treatment of breast cancer after whole breast radiotherapy and to identify factors affecting cosmetic outcomes. Methods and Materials: Between 1996 and 1998, 142 patients with Stage I and II breast cancer were treated with breast conservative surgery and adjuvant RT. Patients were then randomly assigned to receive a boost dose of 15 Gy delivered to the tumor bed either by iridium 192, or a combination of photons and electrons. Cosmetic evaluations were done on a 6-month basis, with a final evaluation at 36 months after RT. The evaluations were done using a panel of global and specific subjective scores, a digitized scoring system using the breast retraction assessment (BRA) measurement, and a patient's self-assessment evaluation. As cosmetic results were graded according to severity, the comparison of boost techniques was done using the ordinal logistic regression model. Adjusted odds ratios (OR) and their 95% confidence intervals (CI) are presented. Results: At 36 months of follow-up, there was no significant difference between the two groups with respect to the global subjective cosmetic outcome (OR = 1.40; 95%CI = 0.69-2.85, p = 0.35). Good to excellent scores were observed in 65% of implant patients and 62% of photon/electron patients. At 24 months and beyond, telangiectasia was more severe in the implant group with an OR of 9.64 (95%CI = 4.05-22.92, p < 0.0001) at 36 months. The only variable associated with a worse global cosmetic outcome was the presence of concomitant chemotherapy (OR = 3.87; 95%CI = 1.74-8.62). The BRA value once adjusted for age, concomitant chemotherapy, and boost volume showed a positive association with the boost technique. The BRA value was significantly greater in the implant group (p 0.03). There was no difference in the patient's final self-assessment score between the two groups. Three variables were statistically associated with

  11. Techniques of magna-field irradiation

    SciTech Connect

    Shank, B.

    1983-12-01

    Total body irradiation (TBI) techniques have evolved over the years, with the basic goals remaining adequate immunosuppression and/or tumor eradication. TBI technique variables include: machine type and energy, prescription parameters (dose, number of fractions, dose/fraction, dose rate), patient position, therapy room and machine constraints (field size, distance) and beam modifiers (bolus, compensators, shields). Related variables include chemotherapy agents and schedules, and 'boost' radiotherapy. Seven representative institutions that treat a large number of TBI patients were surveyed for these variables. Homogeneity has been achieved generally within +/-10% with the use of these techniques. One 'sentinel' effect is discussed, namely interstitial pneumonitis, as a measure of normal tissue effects with varying techniques. There is an indication that more fractionated methods, used either daily or in a hyperfractionated fashion, are leading to a decreased incidence of pneumonitis.

  12. Whole-Field Simultaneous Integrated-Boost Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

    SciTech Connect

    Wong, Frank C.S.; Ng, Alice W.Y.; Lee, Victor H.F.; Lui, Collin M.M.; Yuen, K.-K.; Sze, W.-K.; Leung, T.-W.; Tung, Stewart Y.

    2010-01-15

    Purpose: To retrospectively review the outcomes of our patients with newly diagnosed nondisseminated nasopharyngeal carcinoma treated with intensity-modulated radiotherapy using a whole-field simultaneous integrated-boost technique. Methods and Materials: A total of 175 patients treated with WF-SIB between mid-2004 and 2005 were eligible for study inclusion. The distribution of disease by stage was Stage IA in 10.9%, Stage IIA in 2.3%, Stage IIB in 21.7%, Stage III in 41.1%, Stage IVA in 14.9%, and Stage IVB in 9.1%. Of the 175 patients, 2 (1.2%), 10 (5.7%), and 163 (93.1%) had World Health Organization type I, II, and III histologic features, respectively. We prescribed 70 Gy, 60 Gy, and 54 Gy delivered in 33 fractions within 6.5 weeks at the periphery of three planning target volumes (PTV; PTV70, PTV60, and PTV54, respectively). Of the 175 patients, 46 with early T-stage disease received a brachytherapy boost, and 127 with advanced local or regional disease received chemotherapy. Results: The median follow-up period was 34 months. The overall 3-year local failure-free survival, regional failure-free survival, distant failure-free survival, and overall survival rate was 93.6%, 93.3%, 86.6%, and 87.2%, respectively. Cox regression analysis showed Stage N2-N3 disease (p = .029) and PTV (p = .024) to be independent factors predicting a greater risk of distant failure and poor overall survival, respectively. Grade 3 acute mucositis/pharyngitis occurred in 23.4% of patients, and Stage T4 disease was the only significant predictor of mucositis/pharyngitis (p = .021). Conclusion: Whole-field simultaneous integrated-boost intensity-modulated radiotherapy with a dose >70 Gy achieved excellent locoregional control, without an excess incidence of severe, acute mucositis/pharyngitis, in the present study. Strategies for using such highly conformal treatment for patients with a large tumor and late N-stage disease are potential areas of investigation for future studies.

  13. Evaluating the potential of mycorrhizal fungi to boost yields in field grown leeks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    UMaine Cooperative Extension faculty collaborated with a local organic grower and the USDA-ARS Research Center in Wyndmoor, PA to evaluate the potential of mycorrhizal fungi to boost yields in field grown leeks using both commercially available mycorrhizal inocula and a “farm raised” mycorrhizal ino...

  14. BOOST H2O - Field Training Activities for Hydrologic Science near Lake Iznik, Turkey

    NASA Astrophysics Data System (ADS)

    Derin, Y.; Hatipoglu, E.; Sunnetci, M. O.; Tanyas, H.; Unal Ercan, H.; Aktuna, Z.; Agouridis, C.; Fryar, A. E.; Milewski, A.; Schroeder, P.; Ece, O. I.; Yilmaz, K. K.

    2013-12-01

    Field activities are often the best pedagogy for reinforcing principles learned in the classroom. As part of the 'Building Opportunity Out of Science and Technology: Helping Hydrologic Outreach (BOOST H2O)' project, which is supported by the U.S. Department of State, six graduate students from three Turkish universities, four U.S. professors, and two Turkish professors participated in a week of training activities during May-June 2013. Field activities took place in the Lake Iznik region in western Turkey. The lake basin is geologically complex, with fault-controlled hydrogeology, and land use is dominated by agriculture, particularly olive cultivation. Professors trained the students (four females and two males) on concepts and techniques in surface-water and groundwater hydrology, water quality, and related computer software. Activities included stream gauging (using top-setting rods and a current meter), geomorphic assessment of streams (slope, cross-sections, and bed-clast size), measuring depth to water in wells, and collection of water samples from springs, wells, and the lake. Measurements of pH, temperature, electrical conductivity, and alkalinity were performed along with sampling for stable isotope (oxygen and hydrogen) analysis. The students visited local villages, farms, surface-water intakes, and recreational springs for a holistic approach towards integrated water resource management. Results were discussed in the context of lithology, tectonics, land use, and other human impacts.

  15. High-accuracy current sensing circuit with current compensation technique for buck-boost converter

    NASA Astrophysics Data System (ADS)

    Rao, Yuan; Deng, Wan-Ling; Huang, Jun-Kai

    2015-03-01

    A novel on-chip current sensing circuit with current compensation technique suitable for buck-boost converter is presented in this article. The proposed technique can sense the full-range inductor current with high accuracy and high speed. It is mainly based on matched current mirror and does not require a large proportion of aspect ratio between the powerFET and the senseFET, thus it reduces the complexity of circuit design and the layout mismatch issue without decreasing the power efficiency. The circuit is fabricated with TSMC 0.25 µm 2P5M mixed-signal process. Simulation results show that the buck-boost converter can be operated at 200 kHz to 4 MHz switching frequency with an input voltage from 2.8 to 4.7 V. The output voltage is 3.6 V, and the maximum accuracy for both high and low side sensing current reaches 99% within the load current ranging from 200 to 600 mA.

  16. A Boost for the Emerging Field of RNA Nanotechnology

    PubMed Central

    2011-01-01

    This Nano Focus article highlights recent advances in RNA nanotechnology as presented at the First International Conference of RNA Nanotechnology and Therapeutics, which took place in Cleveland, OH, USA (October 23–25, 2010) (http://www.eng.uc.edu/nanomedicine/RNA2010/), chaired by Peixuan Guo and co-chaired by David Rueda and Scott Tenenbaum. The conference was the first of its kind to bring together more than 30 invited speakers in the frontier of RNA nanotechnology from France, Sweden, South Korea, China, and throughout the United States to discuss RNA nanotechnology and its applications. It provided a platform for researchers from academia, government, and the pharmaceutical industry to share existing knowledge, vision, technology, and challenges in the field and promoted collaborations among researchers interested in advancing this emerging scientific discipline. The meeting covered a range of topics, including biophysical and single-molecule approaches for characterization of RNA nanostructures; structure studies on RNA nanoparticles by chemical or biochemical approaches, computation, prediction, and modeling of RNA nanoparticle structures; methods for the assembly of RNA nanoparticles; chemistry for RNA synthesis, conjugation, and labeling; and application of RNA nanoparticles in therapeutics. A special invited talk on the well-established principles of DNA nanotechnology was arranged to provide models for RNA nanotechnology. An Administrator from National Institutes of Health (NIH) National Cancer Institute (NCI) Alliance for Nanotechnology in Cancer discussed the current nanocancer research directions and future funding opportunities at NCI. As indicated by the feedback received from the invited speakers and the meeting participants, this meeting was extremely successful, exciting, and informative, covering many groundbreaking findings, pioneering ideas, and novel discoveries. PMID:21604810

  17. A boost for the emerging field of RNA nanotechnology.

    PubMed

    Shukla, Girish C; Haque, Farzin; Tor, Yitzhak; Wilhelmsson, L Marcus; Toulmé, Jean-Jacques; Isambert, Hervé; Guo, Peixuan; Rossi, John J; Tenenbaum, Scott A; Shapiro, Bruce A

    2011-05-24

    This Nano Focus article highlights recent advances in RNA nanotechnology as presented at the First International Conference of RNA Nanotechnology and Therapeutics, which took place in Cleveland, OH, USA (October 23-25, 2010) ( http://www.eng.uc.edu/nanomedicine/RNA2010/ ), chaired by Peixuan Guo and co-chaired by David Rueda and Scott Tenenbaum. The conference was the first of its kind to bring together more than 30 invited speakers in the frontier of RNA nanotechnology from France, Sweden, South Korea, China, and throughout the United States to discuss RNA nanotechnology and its applications. It provided a platform for researchers from academia, government, and the pharmaceutical industry to share existing knowledge, vision, technology, and challenges in the field and promoted collaborations among researchers interested in advancing this emerging scientific discipline. The meeting covered a range of topics, including biophysical and single-molecule approaches for characterization of RNA nanostructures; structure studies on RNA nanoparticles by chemical or biochemical approaches, computation, prediction, and modeling of RNA nanoparticle structures; methods for the assembly of RNA nanoparticles; chemistry for RNA synthesis, conjugation, and labeling; and application of RNA nanoparticles in therapeutics. A special invited talk on the well-established principles of DNA nanotechnology was arranged to provide models for RNA nanotechnology. An Administrator from National Institutes of Health (NIH) National Cancer Institute (NCI) Alliance for Nanotechnology in Cancer discussed the current nanocancer research directions and future funding opportunities at NCI. As indicated by the feedback received from the invited speakers and the meeting participants, this meeting was extremely successful, exciting, and informative, covering many groundbreaking findings, pioneering ideas, and novel discoveries. PMID:21604810

  18. Boost of plasma current with active magnetic field shaping coils in rotamak discharges

    SciTech Connect

    Yang Xiaokang; Goss, Jermain; Kalaria, Dhara; Huang, Tian Sen

    2011-08-15

    A set of magnetic shaping coils is installed on the Prairie View (PV) rotamak for the study of active plasma shape control in the regimes with and without toroidal field (TF). In the spherical tokamak regime (with TF), plasma current I{sub p} can be boosted by 200% when all five shaping coils (connected in series) are energized. The enhancement of current drive efficiency is mainly attributed to the radial compression and the substantially axial extension of the plasma column; this in turn improves the impedance matching and thus increases antenna input power. In the field-reversed configuration (without TF), plasma current can be boosted by 100% when one middle coil is used; the appearance of radial shift mode limits the achievable value of I{sub p}. The experiments clearly demonstrate that the plasma shape control plays a role in effectively driving plasma current in rotamaks.

  19. SU-E-T-596: Axillary Nodes Radiotherapy Boost Field Dosimetric Impact Study: Oblique Field and Field Optimization in 3D Conventional Breast Cancer Radiation Treatment

    SciTech Connect

    Su, M; Sura, S

    2014-06-01

    Purpose: To evaluate dosimetric impact of two axillary nodes (AX) boost techniques: (1) posterior-oblique optimized field boost (POB), (2) traditional posterior-anterior boost (PAB) with field optimization (O-PAB), for a postmastectomy breast patient with positive axillary lymph nodes. Methods: Five patients, 3 left and 2 right chest walls, were included in this study. All patients were simulated in 5mm CT slice thickness. Supraclavicular (SC) and level I/II/III AX were contoured based on the RTOG atlas guideline. Five treatment plans, (1) tangential chest wall, (2) oblique SC including AX, (3) PAB, O-PAB and POB, were created for each patient. Three plan sums (PS) were generated by sum one of (3) plan with plan (1) and (2). The field optimization was done through PS dose distribution, which included a field adjustment, a fractional dose, a calculation location and a gantry angle selection for POB. A dosimetric impact was evaluated by comparing a SC and AX coverage, a PS maximum dose, an irradiated area percentage volume received dose over 105% prescription dose (V105), an ipsi-laterial mean lung dose (MLD), an ipsi-laterial mean humeral head dose (MHHD), a mean heart dose (MHD) (for left case only) and their DVH amount these three technique. Results: O-PAB, POB and PAB dosimetric results showed that there was no significant different on SC and AX coverage (p>0.43) and MHD (p>0.16). The benefit of sparing lung irradiation from PAB to O-PAB to POB was significant (p<0.004). PAB showed a highest PS maximum dose (p<0.005), V105 (p<0.023) and MLD (compared with OPAB, p=0.055). MHHD showed very sensitive to the patient arm positioning and anatomy. O-PAB convinced a lower MHHD than PAB (p=0.03). Conclusion: 3D CT contouring plays main role in accuracy radiotherapy. Dosimetric advantage of POB and O-PAB was observed for a better normal tissue irradiation sparing.

  20. Identification techniques for highly boosted W bosons that decay into hadrons

    SciTech Connect

    Khachatryan, Vardan

    2014-12-02

    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMS detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.

  1. Identification techniques for highly boosted W bosons that decay into hadrons

    DOE PAGESBeta

    Khachatryan, Vardan

    2014-12-02

    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMSmore » detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.« less

  2. Bottom-series coupled quadrature VCO using the inductive gate voltage boosting technique

    NASA Astrophysics Data System (ADS)

    Jang, Sheng-Lyang; Chou, Li-Te

    2013-09-01

    This article presents a new low-voltage bottom-series coupled quadrature voltage-controlled oscillator (QVCO), which consists of two n-core cross-coupled VCOs with the bottom-series coupling transistors. The low-voltage operation is obtained via an inductive gate voltage boosting technique. The proposed CMOS QVCO has been implemented with the TSMC 0.18 µm CMOS technology and the die area is 0.897 × 0.767 mm2. At the supply voltage of 0.7 V, the total power consumption is 1.5 mW. The free-running frequency of the QVCO is tuneable from 3.77 to 4.12 GHz as the tuning voltage is varied from 0.0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is -123.35 dBc/Hz at the oscillation frequency of 4.12 GHz and the figure of merit of the proposed QVCO is -193.5 dBc/Hz.

  3. Variances in the projections, resulting from CLIMEX, Boosted Regression Trees and Random Forests techniques

    NASA Astrophysics Data System (ADS)

    Shabani, Farzin; Kumar, Lalit; Solhjouy-fard, Samaneh

    2016-05-01

    The aim of this study was to have a comparative investigation and evaluation of the capabilities of correlative and mechanistic modeling processes, applied to the projection of future distributions of date palm in novel environments and to establish a method of minimizing uncertainty in the projections of differing techniques. The location of this study on a global scale is in Middle Eastern Countries. We compared the mechanistic model CLIMEX (CL) with the correlative models MaxEnt (MX), Boosted Regression Trees (BRT), and Random Forests (RF) to project current and future distributions of date palm (Phoenix dactylifera L.). The Global Climate Model (GCM), the CSIRO-Mk3.0 (CS) using the A2 emissions scenario, was selected for making projections. Both indigenous and alien distribution data of the species were utilized in the modeling process. The common areas predicted by MX, BRT, RF, and CL from the CS GCM were extracted and compared to ascertain projection uncertainty levels of each individual technique. The common areas identified by all four modeling techniques were used to produce a map indicating suitable and unsuitable areas for date palm cultivation for Middle Eastern countries, for the present and the year 2100. The four different modeling approaches predict fairly different distributions. Projections from CL were more conservative than from MX. The BRT and RF were the most conservative methods in terms of projections for the current time. The combination of the final CL and MX projections for the present and 2100 provide higher certainty concerning those areas that will become highly suitable for future date palm cultivation. According to the four models, cold, hot, and wet stress, with differences on a regional basis, appears to be the major restrictions on future date palm distribution. The results demonstrate variances in the projections, resulting from different techniques. The assessment and interpretation of model projections requires reservations

  4. Boosting Local Field Enhancement by on-Chip Nanofocusing and Impedance-Matched Plasmonic Antennas.

    PubMed

    Zenin, Vladimir A; Andryieuski, Andrei; Malureanu, Radu; Radko, Ilya P; Volkov, Valentyn S; Gramotnev, Dmitri K; Lavrinenko, Andrei V; Bozhevolnyi, Sergey I

    2015-12-01

    Strongly confined surface plasmon-polariton modes can be used for efficiently delivering the electromagnetic energy to nanosized volumes by reducing the cross sections of propagating modes far beyond the diffraction limit, that is, by nanofocusing. This process results in significant local-field enhancement that can advantageously be exploited in modern optical nanotechnologies, including signal processing, biochemical sensing, imaging, and spectroscopy. Here, we propose, analyze, and experimentally demonstrate on-chip nanofocusing followed by impedance-matched nanowire antenna excitation in the end-fire geometry at telecom wavelengths. Numerical and experimental evidence of the efficient excitation of dipole and quadrupole (dark) antenna modes are provided, revealing underlying physical mechanisms and analogies with the operation of plane-wave Fabry-Pérot interferometers. The unique combination of efficient nanofocusing and nanoantenna resonant excitation realized in our experiments offers a major boost to the field intensity enhancement up to ∼12000, with the enhanced field being evenly distributed over the gap volume of 30 × 30 × 10 nm(3), and promises thereby a variety of useful on-chip functionalities within sensing, nonlinear spectroscopy and signal processing. PMID:26551324

  5. Pressure boosting technology recovers reserves in low pressure oil and gas fields

    SciTech Connect

    Sarshar, M.M.

    1999-01-01

    Fragmentation of reservoirs or production from different zones often results in oil or gas wells having different flowing wellhead pressures (FWHP). In many fields, the wells flow to a manifold, then the oil and gas is transported by pipeline to a processing plant. Production from the low-pressure (LP) wells is often restricted because of the backpressure imposed by the high-pressure (HP) wells or by the transportation pipeline. To minimize the production restrictions from LP wells, HP wells are usually choked down and their high energy is thus wasted through the choke. A team of engineers from CALTEC, the oil and gas division of BHR Group, have developed a system which harnesses the energy from HP wells to boost production from LP wells. The system is called WELLCOM, short for WELL COMmingling system. This patented system has won the 1998 British Royal Society Esso Energy award for an outstanding contribution to the advancement of science or engineering or technology that leads to a more efficient mobilization, conservation, or use of energy sources.

  6. Hypofractionated Accelerated Radiotherapy Using Concomitant Intensity-Modulated Radiotherapy Boost Technique for Localized High-Risk Prostate Cancer: Acute Toxicity Results

    SciTech Connect

    Lim, Tee S.; Cheung, Patrick Loblaw, D. Andrew; Morton, Gerard; Sixel, Katharina E.; Pang, Geordi; Basran, Parminder; Zhang Liying; Tirona, Romeo; Szumacher, Ewa; Danjoux, Cyril; Choo, Richard; Thomas, Gillian

    2008-09-01

    Purpose: To evaluate the acute toxicities of hypofractionated accelerated radiotherapy (RT) using a concomitant intensity-modulated RT boost in conjunction with elective pelvic nodal irradiation for high-risk prostate cancer. Methods and Materials: This report focused on 66 patients entered into this prospective Phase I study. The eligible patients had clinically localized prostate cancer with at least one of the following high-risk features (Stage T3, Gleason score {>=}8, or prostate-specific antigen level >20 ng/mL). Patients were treated with 45 Gy in 25 fractions to the pelvic lymph nodes using a conventional four-field technique. A concomitant intensity-modulated radiotherapy boost of 22.5 Gy in 25 fractions was delivered to the prostate. Thus, the prostate received 67.5 Gy in 25 fractions within 5 weeks. Next, the patients underwent 3 years of adjuvant androgen ablative therapy. Acute toxicities were assessed using the Common Terminology Criteria for Adverse Events, version 3.0, weekly during treatment and at 3 months after RT. Results: The median patient age was 71 years. The median pretreatment prostate-specific antigen level and Gleason score was 18.7 ng/L and 8, respectively. Grade 1-2 genitourinary and gastrointestinal toxicities were common during RT but most had settled at 3 months after treatment. Only 5 patients had acute Grade 3 genitourinary toxicity, in the form of urinary incontinence (n = 1), urinary frequency/urgency (n = 3), and urinary retention (n = 1). None of the patients developed Grade 3 or greater gastrointestinal or Grade 4 or greater genitourinary toxicity. Conclusion: The results of the present study have indicated that hypofractionated accelerated RT with a concomitant intensity-modulated RT boost and pelvic nodal irradiation is feasible with acceptable acute toxicity.

  7. Self-Boosted Tunnel Field-Effect Transistor Using Nitride Charge Trapping Layer for Low Supply Voltage Operation.

    PubMed

    Kim, Hyungjin; Kwon, Dae Woong; Kwon, Min-Woo; Park, Jungjin; Park, Byung-Gook

    2016-05-01

    Tunneling field-effect transistors (TFETs) have been studied as a candidate for low-power device due to the remarkable subthreshold characteristics. However, digital circuits composed of TFET have significantly large propagation delay compared with the conventional MOSFET circuits because of small current drivability and large gate-to-drain capacitance. In this work, the electrical characteristics of the self-boosted TFETs with nitride charge trapping layer have been studied using TCAD simulations. Trapped charges in the nitride layer improve subthreshold characteristics and on-current (I(ON)) of both nTFET and pTFET during gate bias sweep. In addition, the benefits of the self-boosted TFET devices to low supply voltage system application are investigated. Energy consumption and propagation delay of both conventional and self-boosted TFET inverters are compared by the mixed-mode circuit simulation study. Energy consumption is almost same but the propagation delay of the self-boosted TFET inverter is reduced especially for ultra-low voltage operation where system delay is increased dramatically. PMID:27483907

  8. APSLAP: an adaptive boosting technique for predicting subcellular localization of apoptosis protein.

    PubMed

    Saravanan, Vijayakumar; Lakshmi, P T V

    2013-12-01

    Apoptotic proteins play key roles in understanding the mechanism of programmed cell death. Knowledge about the subcellular localization of apoptotic protein is constructive in understanding the mechanism of programmed cell death, determining the functional characterization of the protein, screening candidates in drug design, and selecting protein for relevant studies. It is also proclaimed that the information required for determining the subcellular localization of protein resides in their corresponding amino acid sequence. In this work, a new biological feature, class pattern frequency of physiochemical descriptor, was effectively used in accordance with the amino acid composition, protein similarity measure, CTD (composition, translation, and distribution) of physiochemical descriptors, and sequence similarity to predict the subcellular localization of apoptosis protein. AdaBoost with the weak learner as Random-Forest was designed for the five modules and prediction is made based on the weighted voting system. Bench mark dataset of 317 apoptosis proteins were subjected to prediction by our system and the accuracy was found to be 100.0 and 92.4 %, and 90.1 % for self-consistency test, jack-knife test, and tenfold cross validation test respectively, which is 0.9 % higher than that of other existing methods. Beside this, the independent data (N151 and ZW98) set prediction resulted in the accuracy of 90.7 and 87.7 %, respectively. These results show that the protein feature represented by a combined feature vector along with AdaBoost algorithm holds well in effective prediction of subcellular localization of apoptosis proteins. The user friendly web interface "APSLAP" has been constructed, which is freely available at http://apslap.bicpu.edu.in and it is anticipated that this tool will play a significant role in determining the specific role of apoptosis proteins with reliability. PMID:23982307

  9. Field techniques for sampling ants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ants occur in most environments and ecologists ask a diverse array of questions involving ants. Thus, a key consideration in ant studies is to match the environment and question (and associated environmental variables) to the ant sampling technique. Since each technique has distinct limitations, usi...

  10. Can Face-to-Face Mobilization Boost Student Voter Turnout? Results of a Campus Field Experiment

    ERIC Educational Resources Information Center

    Hill, David; Lachelier, Paul

    2014-01-01

    American colleges and universities have an expanding role to play in nurturing political engagement as more youth attend college. Given low voter turnout among college students yet growing experimental evidence that face-to-face mobilization can boost turnout, the experiment reported in this article examined the impact of a face-to-face college…

  11. Simplified field-in-field technique for a large-scale implementation in breast radiation treatment

    SciTech Connect

    Fournier-Bidoz, Nathalie; Kirova, Youlia M.; Campana, Francois; Dendale, Remi; Fourquet, Alain

    2012-07-01

    We wanted to evaluate a simplified 'field-in-field' technique (SFF) that was implemented in our department of Radiation Oncology for breast treatment. This study evaluated 15 consecutive patients treated with a simplified field in field technique after breast-conserving surgery for early-stage breast cancer. Radiotherapy consisted of whole-breast irradiation to the total dose of 50 Gy in 25 fractions, and a boost of 16 Gy in 8 fractions to the tumor bed. We compared dosimetric outcomes of SFF to state-of-the-art electronic surface compensation (ESC) with dynamic leaves. An analysis of early skin toxicity of a population of 15 patients was performed. The median volume receiving at least 95% of the prescribed dose was 763 mL (range, 347-1472) for SFF vs. 779 mL (range, 349-1494) for ESC. The median residual 107% isodose was 0.1 mL (range, 0-63) for SFF and 1.9 mL (range, 0-57) for ESC. Monitor units were on average 25% higher in ESC plans compared with SFF. No patient treated with SFF had acute side effects superior to grade 1-NCI scale. SFF created homogenous 3D dose distributions equivalent to electronic surface compensation with dynamic leaves. It allowed the integration of a forward planned concomitant tumor bed boost as an additional multileaf collimator subfield of the tangential fields. Compared with electronic surface compensation with dynamic leaves, shorter treatment times allowed better radiation protection to the patient. Low-grade acute toxicity evaluated weekly during treatment and 2 months after treatment completion justified the pursuit of this technique for all breast patients in our department.

  12. Stereotactic Body Radiotherapy as Monotherapy or Post-External Beam Radiotherapy Boost for Prostate Cancer: Technique, Early Toxicity, and PSA Response

    SciTech Connect

    Jabbari, Siavash; Weinberg, Vivian K.; Kaprealian, Tania; Hsu, I-Chow; Ma Lijun; Chuang, Cynthia; Descovich, Martina; Shiao, Stephen; Shinohara, Katsuto; Roach, Mack; Gottschalk, Alexander R.

    2012-01-01

    Purpose: High dose rate (HDR) brachytherapy has been established as an excellent monotherapy or after external-beam radiotherapy (EBRT) boost treatment for prostate cancer (PCa). Recently, dosimetric studies have demonstrated the potential for achieving similar dosimetry with stereotactic body radiotherapy (SBRT) compared with HDR brachytherapy. Here, we report our technique, PSA nadir, and acute and late toxicity with SBRT as monotherapy and post-EBRT boost for PCa using HDR brachytherapy fractionation. Patients and Methods: To date, 38 patients have been treated with SBRT at University of California-San Francisco with a minimum follow-up of 12 months. Twenty of 38 patients were treated with SBRT monotherapy (9.5 Gy Multiplication-Sign 4 fractions), and 18 were treated with SBRT boost (9.5 Gy Multiplication-Sign 2 fractions) post-EBRT and androgen deprivation therapy. PSA nadir to date for 44 HDR brachytherapy boost patients with disease characteristics similar to the SBRT boost cohort was also analyzed as a descriptive comparison. Results: SBRT was well tolerated. With a median follow-up of 18.3 months (range, 12.6-43.5), 42% and 11% of patients had acute Grade 2 gastrourinary and gastrointestinal toxicity, respectively, with no Grade 3 or higher acute toxicity to date. Two patients experienced late Grade 3 GU toxicity. All patients are without evidence of biochemical or clinical progression to date, and favorably low PSA nadirs have been observed with a current median PSA nadir of 0.35 ng/mL (range, <0.01-2.1) for all patients (0.47 ng/mL, range, 0.2-2.1 for the monotherapy cohort; 0.10 ng/mL, range, 0.01-0.5 for the boost cohort). With a median follow-up of 48.6 months (range, 16.4-87.8), the comparable HDR brachytherapy boost cohort has achieved a median PSA nadir of 0.09 ng/mL (range, 0.0-3.3). Conclusions: Early results with SBRT monotherapy and post-EBRT boost for PCa demonstrate acceptable PSA response and minimal toxicity. PSA nadir with SBRT boost

  13. A Corpus-Based Approach for Automatic Thai Unknown Word Recognition Using Boosting Techniques

    NASA Astrophysics Data System (ADS)

    Techo, Jakkrit; Nattee, Cholwich; Theeramunkong, Thanaruk

    While classification techniques can be applied for automatic unknown word recognition in a language without word boundary, it faces with the problem of unbalanced datasets where the number of positive unknown word candidates is dominantly smaller than that of negative candidates. To solve this problem, this paper presents a corpus-based approach that introduces a so-called group-based ranking evaluation technique into ensemble learning in order to generate a sequence of classification models that later collaborate to select the most probable unknown word from multiple candidates. Given a classification model, the group-based ranking evaluation (GRE) is applied to construct a training dataset for learning the succeeding model, by weighing each of its candidates according to their ranks and correctness when the candidates of an unknown word are considered as one group. A number of experiments have been conducted on a large Thai medical text to evaluate performance of the proposed group-based ranking evaluation approach, namely V-GRE, compared to the conventional naïve Bayes classifier and our vanilla version without ensemble learning. As the result, the proposed method achieves an accuracy of 90.93±0.50% when the first rank is selected while it gains 97.26±0.26% when the top-ten candidates are considered, that is 8.45% and 6.79% improvement over the conventional record-based naïve Bayes classifier and the vanilla version. Another result on applying only best features show 93.93±0.22% and up to 98.85±0.15% accuracy for top-1 and top-10, respectively. They are 3.97% and 9.78% improvement over naive Bayes and the vanilla version. Finally, an error analysis is given.

  14. Hypofractionated high-dose irradiation for the treatment of malignant astrocytomas using simultaneous integrated boost technique by IMRT

    SciTech Connect

    Iuchi, Toshihiko; Hatano, Kazuo; Narita, Yuichiro; Kodama, Takashi; Yamaki, Tomohiro; Osato, Katsunobu

    2006-04-01

    Purpose: We evaluated the clinical significance of hypofractionated high-dose irradiation using simultaneous integrated boost technique with intensity-modulated radiation therapy (IMRT) for the treatment of malignant astrocytomas (MAs). Methods and Materials: Twenty-five patients with MAs were treated by IMRT. Three layered planning target volumes (PTVs) were contoured. PTV-1 was the area of enhanced lesion with 5-mm margin; PTV-2 was the area with 15-mm margin surrounding the PTV-1; PTV-3 was the area of perifocal edema. Irradiation was performed in 8 fractions, and only the dose for PTV-1 was escalated from 48 Gy to 68 Gy while maintaining the dose for PTV-2 (40 Gy) and PTV-3 (32 Gy). The clinical outcome of IMRT was compared with 60 MA patients treated by conventional external beam irradiation (EBI). Results: The progression-free survival of patients in the IMRT group was significantly longer than that in the EBI group (p < 0.0001). No distant failure was observed in both groups. In the IMRT group, dissemination was the most frequent cause of death (70%). The overall survival of patients in the IMRT group was better than that in the EBI group (p = 0.043). Conclusions: Our regimen of IMRT contributed to the control of both the regional and infiltrating tumors, resulting in better survival of patients.

  15. Boosting Higgs pair production in the bbar{b}bbar{b} final state with multivariate techniques

    NASA Astrophysics Data System (ADS)

    Behr, J. Katharina; Bortoletto, Daniela; Frost, James A.; Hartland, Nathan P.; Issever, Cigdem; Rojo, Juan

    2016-07-01

    The measurement of Higgs pair production will be a cornerstone of the LHC program in the coming years. Double Higgs production provides a crucial window upon the mechanism of electroweak symmetry breaking and has a unique sensitivity to the Higgs trilinear coupling. We study the feasibility of a measurement of Higgs pair production in the bbar{b}bbar{b} final state at the LHC. Our analysis is based on a combination of traditional cut-based methods with state-of-the-art multivariate techniques. We account for all relevant backgrounds, including the contributions from light and charm jet mis-identification, which are ultimately comparable in size to the irreducible 4 b QCD background. We demonstrate the robustness of our analysis strategy in a high pileup environment. For an integrated luminosity of L=3 ab^{-1}, a signal significance of S/√{B}˜eq 3 is obtained, indicating that the bbar{b}bbar{b} final state alone could allow for the observation of double Higgs production at the High Luminosity LHC.

  16. Gravity field determination and error assessment techniques

    NASA Technical Reports Server (NTRS)

    Yuan, D. N.; Shum, C. K.; Tapley, B. D.

    1989-01-01

    Linear estimation theory, along with a new technique to compute relative data weights, was applied to the determination of the Earth's geopotential field and other geophysical model parameters using a combination of satellite ground-based tracking data, satellite altimetry data, and the surface gravimetry data. The relative data weights for the inhomogeneous data sets are estimated simultaneously with the gravity field and other geophysical and orbit parameters in a least squares approach to produce the University of Texas gravity field models. New techniques to perform calibration of the formal covariance matrix for the geopotential solution were developed to obtain a reliable gravity field error estimate. Different techniques, which include orbit residual analysis, surface gravity anomaly residual analysis, subset gravity solution comparisons and consider covariance analysis, were applied to investigate the reliability of the calibration.

  17. A Phase I Dose Escalation Study of Hypofractionated IMRT Field-in-Field Boost for Newly Diagnosed Glioblastoma Multiforme

    SciTech Connect

    Monjazeb, Arta M.; Ayala, Deandra; Jensen, Courtney; Case, L. Douglas; Bourland, J. Daniel; Ellis, Thomas L.; McMullen, Kevin P.; Chan, Michael D.; Tatter, Stephen B.; Lesser, Glen J.; Shaw, Edward G.

    2012-02-01

    Objectives: To describe the results of a Phase I dose escalation trial for newly diagnosed glioblastoma multiforme (GBM) using a hypofractionated concurrent intensity-modulated radiotherapy (IMRT) boost. Methods: Twenty-one patients were enrolled between April 1999 and August 2003. Radiotherapy consisted of daily fractions of 1.8 Gy with a concurrent boost of 0.7 Gy (total 2.5 Gy daily) to a total dose of 70, 75, or 80 Gy. Concurrent chemotherapy was not permitted. Seven patients were enrolled at each dose and dose limiting toxicities were defined as irreversible Grade 3 or any Grade 4-5 acute neurotoxicity attributable to radiotherapy. Results: All patients experienced Grade 1 or 2 acute toxicities. Acutely, 8 patients experienced Grade 3 and 1 patient experienced Grade 3 and 4 toxicities. Of these, only two reversible cases of otitis media were attributable to radiotherapy. No dose-limiting toxicities were encountered. Only 2 patients experienced Grade 3 delayed toxicity and there was no delayed Grade 4 toxicity. Eleven patients requiring repeat resection or biopsy were found to have viable tumor and radiation changes with no cases of radionecrosis alone. Median overall and progression-free survival for this cohort were 13.6 and 6.5 months, respectively. One- and 2-year survival rates were 57% and 19%. At recurrence, 15 patients received chemotherapy, 9 underwent resection, and 5 received radiotherapy. Conclusions: Using a hypofractionated concurrent IMRT boost, we were able to safely treat patients to 80 Gy without any dose-limiting toxicity. Given that local failure still remains the predominant pattern for GBM patients, a trial of dose escalation with IMRT and temozolomide is warranted.

  18. Preliminary analysis of the sequential simultaneous integrated boost technique for intensity-modulated radiotherapy for head and neck cancers

    PubMed Central

    Miyazaki, Masayoshi; Nishiyama, Kinji; Ueda, Yoshihiro; Ohira, Shingo; Tsujii, Katsutomo; Isono, Masaru; Masaoka, Akira; Teshima, Teruki

    2016-01-01

    The aim of this study was to compare three strategies for intensity-modulated radiotherapy (IMRT) for 20 head-and-neck cancer patients. For simultaneous integrated boost (SIB), doses were 66 and 54 Gy in 30 fractions for PTVboost and PTVelective, respectively. Two-phase IMRT delivered 50 Gy in 25 fractions to PTVelective in the First Plan, and 20 Gy in 10 fractions to PTVboost in the Second Plan. Sequential SIB (SEQ-SIB) delivered 55 Gy and 50 Gy in 25 fractions, respectively, to PTVboost and PTVelective using SIB in the First Plan and 11 Gy in 5 fractions to PTVboost in the Second Plan. Conformity indexes (CIs) (mean ± SD) for PTVboost and PTVelective were 1.09 ± 0.05 and 1.34 ± 0.12 for SIB, 1.39 ± 0.14 and 1.80 ± 0.28 for two-phase IMRT, and 1.14 ± 0.07 and 1.60 ± 0.18 for SEQ-SIB, respectively. CI was significantly highest for two-phase IMRT. Maximum doses (Dmax) to the spinal cord were 42.1 ± 1.5 Gy for SIB, 43.9 ± 1.0 Gy for two-phase IMRT and 40.3 ± 1.8 Gy for SEQ-SIB. Brainstem Dmax were 50.1 ± 2.2 Gy for SIB, 50.5 ± 4.6 Gy for two-phase IMRT and 47.4 ± 3.6 Gy for SEQ-SIB. Spinal cord Dmax for the three techniques was significantly different, and brainstem Dmax was significantly lower for SEQ-SIB. The compromised conformity of two-phase IMRT can result in higher doses to organs at risk (OARs). Lower OAR doses in SEQ-SIB made SEQ-SIB an alternative to SIB, which applies unconventional doses per fraction. PMID:26983983

  19. Phase I Trial of Simultaneous In-Field Boost With Helical Tomotherapy for Patients With One to Three Brain Metastases

    SciTech Connect

    Rodrigues, George; Yartsev, Slav; Yaremko, Brian; Perera, Francisco; Dar, A. Rashid; Hammond, Alex; Lock, Michael; Yu, Edward; Ash, Robert; Caudrelier, Jean-Michelle; Khuntia, Deepak; Bailey, Laura; Bauman, Glenn

    2011-07-15

    Purpose: Stereotactic radiosurgery is an alternative to surgical resection for selected intracranial lesions. Integrated image-guided intensity-modulated-capable radiotherapy platforms such as helical tomotherapy (HT) could potentially replace traditional radiosurgery apparatus. The present study's objective was to determine the maximally tolerated dose of a simultaneous in-field boost integrated with whole brain radiotherapy for palliative treatment of patients with one to three brain metastases using HT. Methods and Materials: The inclusion/exclusion criteria and endpoints were consistent with the Radiation Therapy Oncology Group 9508 radiosurgery trial. The cohorts were constructed with a 3 + 3 design; however, additional patients were enrolled in the lower dose tolerable cohorts during the toxicity assessment periods. Whole brain radiotherapy (30 Gy in 10 fractions) was delivered with a 5-30-Gy (total lesion dose of 35-60 Gy in 10 fractions) simultaneous in-field boost delivered to the brain metastases. The maximally tolerated dose was determined by the frequency of neurologic Grade 3-5 National Cancer Institute Common Toxicity Criteria, version 3.0, dose-limiting toxicity events within each Phase I cohort. Results: A total of 48 patients received treatment in the 35-Gy (n = 3), 40-Gy (n = 16), 50-Gy (n = 15), 55-Gy (n = 8), and 60-Gy (n = 6) cohorts. No patients experienced dose-limiting toxicity events in any of the trial cohorts. The 3-month RECIST assessments available for 32 of the 48 patients demonstrated a complete response in 2, a partial response in 16, stable disease in 6, and progressive disease in 8 patients. Conclusion: The delivery of 60 Gy in 10 fractions to one to three brain metastases synchronously with 30 Gy whole brain radiotherapy was achieved without dose-limiting central nervous system toxicity as assessed 3 months after treatment. This approach is being tested in a Phase II efficacy trial.

  20. Boosted photocatalytic efficiency through plasmonic field confinement with bowtie and diabolo nanostructures under LED irradiation.

    PubMed

    Lee, Chia-Hua; Liao, Shih-Chieh; Lin, Tzy-Rong; Wang, Shing-Hoa; Lai, Dong-Yan; Chiu, Po-Kai; Lee, Jyh-Wei; Wu, Wen-Fa

    2016-08-01

    Photoresist and electron beam lithography techniques were used to fabricate embedded Ag bowtie and diabolo nanostructures with various apex angles on the surface of a TiO2 film. The reinforced localized surface plasmon resonance (LSPR) and electric field generated at both the Ag/TiO2 and air/TiO2 interfaces enabled high light absorbance in the TiO2 nanostructure. Results for both the bowtie and diabolo nanostructures showed that a reduction in the apex angle enhances both LSPR and Raman intensity. The maximum electric current density observed at the apex indicates that the strongest SPR confines at the tip gap of the bowtie and corners of the diabolo. In a long-wavelength region, as the apex angle increases, the resonant peak wavelength of the standing wave matches the increased length of the prism edges of the bowtie and diabolo to create a redshift. In a short-wavelength region, as the apex angle increases, the blueshift of the resonant peak wavelength is presumably attributable to the increase in the effective index of the local surface plasmon polariton standing wave mainly residing along both the bowtie and diabolo axes. The redshift and blueshift trend in the simulation results for the resonant peak wavelength agrees well with the experimental results. The fastest photocatalytic rate was obtained by placing the Ag/TiO2 bowtie at an apex angle of 30° in the methylene blue solution, revealing that the plasmonic photocatalysis causes the highest degradation efficiency. This is because the Schottky junction and LSPR can stimulate many valid radicals for the environmental improvement. PMID:27505725

  1. Gradient boosting machines, a tutorial.

    PubMed

    Natekin, Alexey; Knoll, Alois

    2013-01-01

    Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods with a strong focus on machine learning aspects of modeling. A theoretical information is complemented with descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. Three practical examples of gradient boosting applications are presented and comprehensively analyzed. PMID:24409142

  2. Gradient boosting machines, a tutorial

    PubMed Central

    Natekin, Alexey; Knoll, Alois

    2013-01-01

    Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods with a strong focus on machine learning aspects of modeling. A theoretical information is complemented with descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. Three practical examples of gradient boosting applications are presented and comprehensively analyzed. PMID:24409142

  3. Soil Sampling Techniques For Alabama Grain Fields

    NASA Technical Reports Server (NTRS)

    Thompson, A. N.; Shaw, J. N.; Mask, P. L.; Touchton, J. T.; Rickman, D.

    2003-01-01

    Characterizing the spatial variability of nutrients facilitates precision soil sampling. Questions exist regarding the best technique for directed soil sampling based on a priori knowledge of soil and crop patterns. The objective of this study was to evaluate zone delineation techniques for Alabama grain fields to determine which method best minimized the soil test variability. Site one (25.8 ha) and site three (20.0 ha) were located in the Tennessee Valley region, and site two (24.2 ha) was located in the Coastal Plain region of Alabama. Tennessee Valley soils ranged from well drained Rhodic and Typic Paleudults to somewhat poorly drained Aquic Paleudults and Fluventic Dystrudepts. Coastal Plain s o i l s ranged from coarse-loamy Rhodic Kandiudults to loamy Arenic Kandiudults. Soils were sampled by grid soil sampling methods (grid sizes of 0.40 ha and 1 ha) consisting of: 1) twenty composited cores collected randomly throughout each grid (grid-cell sampling) and, 2) six composited cores collected randomly from a -3x3 m area at the center of each grid (grid-point sampling). Zones were established from 1) an Order 1 Soil Survey, 2) corn (Zea mays L.) yield maps, and 3) airborne remote sensing images. All soil properties were moderately to strongly spatially dependent as per semivariogram analyses. Differences in grid-point and grid-cell soil test values suggested grid-point sampling does not accurately represent grid values. Zones created by soil survey, yield data, and remote sensing images displayed lower coefficient of variations (8CV) for soil test values than overall field values, suggesting these techniques group soil test variability. However, few differences were observed between the three zone delineation techniques. Results suggest directed sampling using zone delineation techniques outlined in this paper would result in more efficient soil sampling for these Alabama grain fields.

  4. Improved modeling techniques for turbomachinery flow fields

    SciTech Connect

    Lakshminarayana, B.; Fagan, J.R. Jr.

    1995-12-31

    This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbomachinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. This will be accomplished in a cooperative program by Penn State University and the Allison Engine Company. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tenor.

  5. Giant Enhancement of Internal Electric Field Boosting Bulk Charge Separation for Photocatalysis.

    PubMed

    Li, Jie; Cai, Lejuan; Shang, Jian; Yu, Ying; Zhang, Lizhi

    2016-06-01

    Incorporating carbon into Bi3 O4 Cl enhances its internal electric field by 126 times, which induces a bulk charge separation efficiency (ηbulk ) of 80%. This ultrahigh ηbulk value presents a state-of-the-art result in tuning the bulk charge separation. The generated C-doped Bi3 O4 Cl has a noble-metal- and electron-scavenger-free water-oxidation ability under visible light, which is difficult to achieve with most existing photocatalysts. PMID:27001143

  6. High-dose simultaneously integrated breast boost using intensity-modulated radiotherapy and inverse optimization

    SciTech Connect

    Hurkmans, Coen W. . E-mail: coen.hurkmans@cze.nl; Meijer, Gert J.; Vliet-Vroegindeweij, Corine van; Cassee, Jorien

    2006-11-01

    Purpose: Recently a Phase III randomized trial has started comparing a boost of 16 Gy as part of whole-breast irradiation to a high boost of 26 Gy in young women. Our main aim was to develop an efficient simultaneously integrated boost (SIB) technique for the high-dose arm of the trial. Methods and Materials: Treatment planning was performed for 5 left-sided and 5 right-sided tumors. A tangential field intensity-modulated radiotherapy technique added to a sequentially planned 3-field boost (SEQ) was compared with a simultaneously planned technique (SIB) using inverse optimization. Normalized total dose (NTD)-corrected dose volume histogram parameters were calculated and compared. Results: The intended NTD was produced by 31 fractions of 1.66 Gy to the whole breast and 2.38 Gy to the boost volume. The average volume of the PTV-breast and PTV-boost receiving more than 95% of the prescribed dose was 97% or more for both techniques. Also, the mean lung dose and mean heart dose did not differ much between the techniques, with on average 3.5 Gy and 2.6 Gy for the SEQ and 3.8 Gy and 2.6 Gy for the SIB, respectively. However, the SIB resulted in a significantly more conformal irradiation of the PTV-boost. The volume of the PTV-breast, excluding the PTV-boost, receiving a dose higher than 95% of the boost dose could be reduced considerably using the SIB as compared with the SEQ from 129 cc (range, 48-262 cc) to 58 cc (range, 30-102 cc). Conclusions: A high-dose simultaneously integrated breast boost technique has been developed. The unwanted excessive dose to the breast was significantly reduced.

  7. Improved modeling techniques for turbomachinery flow fields

    SciTech Connect

    Lakshminarayana, B.; Fagan, J.R. Jr.

    1995-10-01

    This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbo-machinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tensor. Penn State will lead the effort to make direct measurements of the momentum and thermal mixing stress tensors in high-speed multistage compressor flow field in the turbomachinery laboratory at Penn State. They will also process the data by both conventional and conditional spectrum analysis to derive momentum and thermal mixing stress tensors due to blade-to-blade periodic and aperiodic components, revolution periodic and aperiodic components arising from various blade rows and non-deterministic (which includes random components) correlations. The modeling results from this program will be publicly available and generally applicable to steady-state Navier-Stokes solvers used for turbomachinery component (compressor or turbine) flow field predictions. These models will lead to improved methodology, including loss and efficiency prediction, for the design of high-efficiency turbomachinery and drastically reduce the time required for the design and development cycle of turbomachinery.

  8. Do warning calls boost survival of signal recipients? Evidence from a field experiment in a group-living bird species

    PubMed Central

    2013-01-01

    Introduction Warning calls are a widespread anti-predator adaptation, which can signal unprofitability to predators or alert other potential targets of the predator. Although it is tacitly assumed that the recipients of warning calls experience a reduction in predation risk, this crucial assumption remains untested. Here I tested this hypothesis with a field experiment in the group-living Siberian jay, Perisoreus infaustus. I exposed male or female breeding adults that were foraging together with a non-breeder (related or unrelated) to a model of their main predator (goshawk Accipiter gentilis) in autumn. I then recorded the warning call response of breeders as well as the reaction time of non-breeders, and followed the subsequent survival of non-breeders until spring. Results In most experiments (73%), non-breeders were warned by the more experienced breeders. Warning calls almost halved the reaction time of non-breeders during the experiment and influenced the survival of call recipients: non-breeders that were warned had a higher subsequent survival (19 out of 23) than non-breeders that were not warned (2 out of 5). However, neither kinship, group size, the age of the non-breeder, or the habitat structure of the territory had an influence on the survival subsequent to the experiments. Conclusions Since earlier studies showed that breeders are consistent in their warning call investment across different contexts, breeders that did warn non-breeders in the experiment were likely to have done so in subsequent, natural attacks. Consequently non-breeders living with breeders that called had a better chance of surviving predator attacks. Thus, these results suggest that warning calls have the potential to boost the survival of signal recipients, confirming a pivotal, yet hitherto untested assumption of the effect of warning calls. PMID:23941356

  9. Robust boosting via convex optimization

    NASA Astrophysics Data System (ADS)

    Rätsch, Gunnar

    2001-12-01

    In this work we consider statistical learning problems. A learning machine aims to extract information from a set of training examples such that it is able to predict the associated label on unseen examples. We consider the case where the resulting classification or regression rule is a combination of simple rules - also called base hypotheses. The so-called boosting algorithms iteratively find a weighted linear combination of base hypotheses that predict well on unseen data. We address the following issues: o The statistical learning theory framework for analyzing boosting methods. We study learning theoretic guarantees on the prediction performance on unseen examples. Recently, large margin classification techniques emerged as a practical result of the theory of generalization, in particular Boosting and Support Vector Machines. A large margin implies a good generalization performance. Hence, we analyze how large the margins in boosting are and find an improved algorithm that is able to generate the maximum margin solution. o How can boosting methods be related to mathematical optimization techniques? To analyze the properties of the resulting classification or regression rule, it is of high importance to understand whether and under which conditions boosting converges. We show that boosting can be used to solve large scale constrained optimization problems, whose solutions are well characterizable. To show this, we relate boosting methods to methods known from mathematical optimization, and derive convergence guarantees for a quite general family of boosting algorithms. o How to make Boosting noise robust? One of the problems of current boosting techniques is that they are sensitive to noise in the training sample. In order to make boosting robust, we transfer the soft margin idea from support vector learning to boosting. We develop theoretically motivated regularized algorithms that exhibit a high noise robustness. o How to adapt boosting to regression problems

  10. Emerging Techniques for Field Device Security

    SciTech Connect

    Schwartz, Moses; Mulder, John; Chavez, Adrian R.; Allan, Benjamin A.

    2014-11-01

    Critical infrastructure, such as electrical power plants and oil refineries, rely on embedded devices to control essential processes. State of the art security is unable to detect attacks on these devices at the hardware or firmware level. We provide an overview of the hardware used in industrial control system field devices, look at how these devices have been attacked, and discuss techniques and new technologies that may be used to secure them. We follow three themes: (1) Inspectability, the capability for an external arbiter to monitor the internal state of a device. (2) Trustworthiness, the degree to which a system will continue to function correctly despite disruption, error, or attack. (3) Diversity, the use of adaptive systems and complexity to make attacks more difficult by reducing the feasible attack surface.

  11. Emerging Techniques for Field Device Security

    DOE PAGESBeta

    Schwartz, Moses; Bechtel Corp.; Mulder, John; Chavez, Adrian R.; Allan, Benjamin A.

    2014-11-01

    Critical infrastructure, such as electrical power plants and oil refineries, rely on embedded devices to control essential processes. State of the art security is unable to detect attacks on these devices at the hardware or firmware level. We provide an overview of the hardware used in industrial control system field devices, look at how these devices have been attacked, and discuss techniques and new technologies that may be used to secure them. We follow three themes: (1) Inspectability, the capability for an external arbiter to monitor the internal state of a device. (2) Trustworthiness, the degree to which a systemmore » will continue to function correctly despite disruption, error, or attack. (3) Diversity, the use of adaptive systems and complexity to make attacks more difficult by reducing the feasible attack surface.« less

  12. Investigating High Field Gravity using Astrophysical Techniques

    SciTech Connect

    Bloom, Elliott D.; /SLAC

    2008-02-01

    The purpose of these lectures is to introduce particle physicists to astrophysical techniques. These techniques can help us understand certain phenomena important to particle physics that are currently impossible to address using standard particle physics experimental techniques. As the subject matter is vast, compromises are necessary in order to convey the central ideas to the reader. Many general references are included for those who want to learn more. The paragraphs below elaborate on the structure of these lectures. I hope this discussion will clarify my motivation and make the lectures easier to follow. The lectures begin with a brief review of more theoretical ideas. First, elements of general relativity are reviewed, concentrating on those aspects that are needed to understand compact stellar objects (white dwarf stars, neutron stars, and black holes). I then review the equations of state of these objects, concentrating on the simplest standard models from astrophysics. After these mathematical preliminaries, Sec. 2(c) discusses 'The End State of Stars'. Most of this section also uses the simplest standard models. However, as these lectures are for particle physicists, I also discuss some of the more recent approaches to the equation of state of very dense compact objects. These particle-physics-motivated equations of state can dramatically change how we view the formation of black holes. Section 3 focuses on the properties of the objects that we want to characterize and measure. X-ray binary systems and Active Galactic Nuclei (AGN) are stressed because the lectures center on understanding very dense stellar objects, black hole candidates (BHCs), and their accompanying high gravitational fields. The use of x-ray timing and gamma-ray experiments is also introduced in this section. Sections 4 and 5 review information from x-ray and gamma-ray experiments. These sections also discuss the current state of the art in x-ray and gamma-ray satellite experiments and

  13. Electron energy boosting in laser-wake-field acceleration with external magnetic field Bapprox1 T and laser prepulses

    SciTech Connect

    Hosokai, Tomonao; Zhidkov, Alexei; Yamazaki, Atsushi; Mizuta, Yoshio; Uesaka, Mitsuru; Kodama, Ryosuke

    2010-03-22

    Hundred-mega-electron-volt electron beams with quasi-monoenergetic distribution, and a transverse geometrical emittance as small as approx0.02 pi mm mrad are generated by low power (7 TW, 45 fs) laser pulses tightly focused in helium gas jets in an external static magnetic field, Bapprox1 T. Generation of monoenergetic beams strongly correlates with appearance of a straight, at least 2 mm length plasma channel in a short time before the main laser pulse and with the energy of copropagating picosecond pedestal pulses (PPP). For a moderate energy PPP, the multiple or staged electron self-injection in the channel gives several narrow peaks in the electron energy distribution.

  14. Comparison of whole-field simultaneous integrated boost VMAT and IMRT in the treatment of nasopharyngeal cancer

    SciTech Connect

    Jin, Xiance; Yi, Jinling; Zhou, Yongqiang; Yan, Huawei; Han, Ce; Xie, Congying

    2013-01-01

    To study the feasibility of using volumetric-modulated arc therapy (VMAT) to deliver whole-field simultaneous integrated boost (WF-SIB) to treat patients with nasopharyngeal cancer (NPC). WF-SIB intensity-modulated radiotherapy (IMRT) plans, one-arc WF-SIB VMAT plans, and two-arc WF-SIB VMAT plans were generated with identical objective functions for 8 patients with NPC of various stages. Isodose distributions and dose-volume histograms were evaluated. Dosimetric and biological quality indices of clinical target volume (CTV) and organs at risk (OARs) were calculated to study the optimization capability of these 3 modalities in the treatment of patients with NPC. The optimization time, delivery time, required monitor units (MUs), and delivery accuracy were also compared to investigate the feasibility of these 3 modalities. There was no significant difference (p = 0.92) in target coverage (TC) between WF-SIB IMRT (99.00 ± 0.79) and two-arc WF-SIB VMAT (97.98 ± 1.29). However, both had higher TC than one-arc VMAT plans (89.92 ± 6.32, p < 0.01). IMRT demonstrated the best protection of the spinal cord, whereas two-arc VMAT showed the minimum D{sub max} to OARs. No other significant differences were observed among these 3 modalities on CTV coverage and OAR sparing. The delivery and MU efficiency of one-arc and two-arc WF-SIB VMAT were greatly improved compared with WF-SIB IMRT. The optimization time of one-arc and two-arc WF-SIB VMAT plans were 5 and 10 times greater than that of WF-SIB IMRT, respectively. The delivery accuracy of WF-SIB VMAT was not affected by the increased freedom. For patients with NPC, one-arc WF-SIB VMAT might not be able to achieve sufficient TC, whereas two-arc WF-SIB VMAT was able to achieve reasonable TC. No significant advantage on OAR protection was demonstrated by VMAT compared with IMRT. WF-SIB VMAT has significantly shorter delivery times, but WF-SIB IMRT may still be the first treatment choice for patients with NPC.

  15. Far field fallout prediction techniques. Doctoral thesis

    SciTech Connect

    Bigelow, W.S. Jr.

    1983-12-01

    A calculational technique for use in predicting fallout far downwind from nuclear bursts is developed and validated. Possible siting strategies for the next generation of missiles might invite a concentrated attack by thousands of nuclear warheads. The resulting fallout field could consist of the superposition of thousands of single burst patterns. The downwind extent of damaging radiation levels would extend beyond the distances to which calculations are usually performed for single bursts. Numerical models currently available cannot be extended to these large downwind distances because of the artificial pattern break up inherent in their numerical quadrature and because of prohibitive computing requirements. Two approaches to this problem are taken here. First, a numerical smoothing which conserves radioactivity is developed to help prevent pattern break up. This is partially successful in that it extends the predictive range farther downwind, but not far enough. The second approach is to abandon the numerical quadrature -- known as disc tossing -- and adopt a whole cloud smearing approach. The key function needed for the smearing approach, the fractional arrival rate of activity on the ground, is derived directly from physical principles and validated by comparison with an extensive series of numerical (disc tosser) predictions.

  16. Boosted apparent horizons

    NASA Astrophysics Data System (ADS)

    Akcay, Sarp

    Boosted black holes play an important role in General Relativity (GR), especially in relation to the binary black hole problem. Solving Einstein vac- uum equations in the strong field regime had long been the holy grail of numerical relativity until the significant breakthroughs made in 2005 and 2006. Numerical relativity plays a crucial role in gravitational wave detection by providing numerically generated gravitational waveforms that help search for actual signatures of gravitational radiation exciting laser interferometric de- tectors such as LIGO, VIRGO and GEO600 here on Earth. Binary black holes orbit each other in an ever tightening adiabatic inspiral caused by energy loss due to gravitational radiation emission. As the orbits shrinks, the holes speed up and eventually move at relativistic speeds in the vicinity of each other (separated by ~ 10M or so where 2M is the Schwarzschild radius). As such, one must abandon the Newtonian notion of a point mass on a circular orbit with tangential velocity and replace it with the concept of black holes, cloaked behind spheroidal event horizons that become distorted due to strong gravity, and further appear distorted because of Lorentz effects from the high orbital velocity. Apparent horizons (AHs) are 2-dimensional boundaries that are trapped surfaces. Conceptually, one can think of them as 'quasi-local' definitions for a black hole horizon. This will be explained in more detail in chapter 2. Apparent horizons are especially important in numerical relativity as they provide a computationally efficient way of describing and locating a black hole horizon. For a stationary spacetime, apparent horizons are 2-dimensional cross-sections of the event horizon, which is itself a 3-dimensional null surface in spacetime. Because an AH is a 2-dimensional cross-section of an event horizon, its area remains invariant under distortions due to Lorentz boosts although its shape changes. This fascinating property of the AH can be

  17. Application of Volumetric Modulated Arc Therapy and Simultaneous Integrated Boost Techniques to Prepare “Safe Margin” in the Rabbit VX2 Limb Tumor Model

    PubMed Central

    Wang, Chong-Wen; Zhou, Yang; Bai, Jing-Ping; Liu, Hao; Liu, Yan; Shi, Guang-Li; Ding, Jiao-Jiao; Ma, Dong-Hui; Li, Wen-Ting; Xie, Peng-Ming; Yan, Yue

    2015-01-01

    Background In this study, we aimed to establish the rabbit VX2 limb tumor model, and then prepare a “necrotic zone” as a safe margin by volumetric modulated arc therapy and simultaneous integrated boost (VMAT-SIB) technique applied in the areas where the tumor is located adjacent to the bone (GTVboost area). Material/Methods Rabbits in the control group (n=10) were not treated, while those in the test group (n=10) were treated with the SIB schedule delivering a dose of 40Gy, 35Gy, 30Gy, and 25Gy to the GTVboost, GTV (gross tumor volume), CTV (clinical target volume), and PTV (planning target volume) in 10 fractions. Magnetic resonance diffusion-weighted imaging (MRDWI), 3-dimensional power Doppler angiography (3D-PDA), and histological changes were observed after radiotherapy. Results After radiotherapy, the two groups showed a significant difference in the GTVboost area. In the test group, the tumor necrosis showed a significantly low signal in DWI and high signal in apparent diffusion coefficient (ADC) maps. The 3D-PDA observation showed that tumor vascular structures decreased significantly. Histological analysis demonstrated that a necrotic zone could be generated in the GTVboost area, and microscopic examination observed cell necrosis and fibroplasia. Conclusions This studies demonstrated the feasibility of using VMAT-SIB technique in the rabbit VX2 limb tumor model. The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability. PMID:26280694

  18. FIELD STUDIES OF GEOMEMBRANE INSTALLATION TECHNIQUES

    EPA Science Inventory

    Fourteen construction sites where geomembranes were being installed were visited to observe subgrade preparation and liner installation techniques. These sites were visited during a study conducted for the U.S. EPA, Solid and Hazardous Waste Research Division. The sites included ...

  19. Track and Field: Technique Through Dynamics.

    ERIC Educational Resources Information Center

    Ecker, Tom

    This book was designed to aid in applying the laws of dynamics to the sport of track and field, event by event. It begins by tracing the history of the discoveries of the laws of motion and the principles of dynamics, with explanations of commonly used terms derived from the vocabularies of the physical sciences. The principles and laws of…

  20. Whole brain radiotherapy plus simultaneous in-field boost with image guided intensity-modulated radiotherapy for brain metastases of non-small cell lung cancer

    PubMed Central

    2014-01-01

    Background Whole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases. However, recent reports on WBRT plus simultaneous in-field boost (SIB) also showed promising outcomes. The objective of present study is to retrospectively evaluate the efficacy and toxicities of WBRT plus SIB with image guided intensity-modulated radiotherapy (IG-IMRT) for inoperable brain metastases of NSCLC. Methods Twenty-nine NSCLC patients with 87 inoperable brain metastases were included in this retrospective study. All patients received WBRT at a dose of 40 Gy/20 f, and SIB boost with IG-IMRT at a dose of 20 Gy/5 f concurrent with WBRT in the fourth week. Prior to each fraction of IG-IMRT boost, on-line positioning verification and correction were used to ensure that the set-up errors were within 2 mm by cone beam computed tomography in all patients. Results The one-year intracranial control rate, local brain failure rate, and distant brain failure rate were 62.9%, 13.8%, and 19.2%, respectively. The two-year intracranial control rate, local brain failure rate, and distant brain failure rate were 42.5%, 30.9%, and 36.4%, respectively. Both median intracranial progression-free survival and median survival were 10 months. Six-month, one-year, and two-year survival rates were 65.5%, 41.4%, and 13.8%, corresponding to 62.1%, 41.4%, and 10.3% of intracranial progression-free survival rates. Patients with Score Index for Radiosurgery in Brain Metastases (SIR) >5, number of intracranial lesions <3, and history of EGFR-TKI treatment had better survival. Three lesions (3.45%) demonstrated radiation necrosis after radiotherapy. Grades 2 and 3 cognitive impairment with grade 2 radiation leukoencephalopathy were observed in 4 (13.8%) and 4 (13.8%) patients. No dosimetric parameters were found to be associated with these late toxicities. Patients received EGFR-TKI treatment had higher incidence of grades 2–3

  1. IsoBED: a tool for automatic calculation of biologically equivalent fractionation schedules in radiotherapy using IMRT with a simultaneous integrated boost (SIB) technique

    PubMed Central

    2011-01-01

    Background An advantage of the Intensity Modulated Radiotherapy (IMRT) technique is the feasibility to deliver different therapeutic dose levels to PTVs in a single treatment session using the Simultaneous Integrated Boost (SIB) technique. The paper aims to describe an automated tool to calculate the dose to be delivered with the SIB-IMRT technique in different anatomical regions that have the same Biological Equivalent Dose (BED), i.e. IsoBED, compared to the standard fractionation. Methods Based on the Linear Quadratic Model (LQM), we developed software that allows treatment schedules, biologically equivalent to standard fractionations, to be calculated. The main radiobiological parameters from literature are included in a database inside the software, which can be updated according to the clinical experience of each Institute. In particular, the BED to each target volume will be computed based on the alpha/beta ratio, total dose and the dose per fraction (generally 2 Gy for a standard fractionation). Then, after selecting the reference target, i.e. the PTV that controls the fractionation, a new total dose and dose per fraction providing the same isoBED will be calculated for each target volume. Results The IsoBED Software developed allows: 1) the calculation of new IsoBED treatment schedules derived from standard prescriptions and based on LQM, 2) the conversion of the dose-volume histograms (DVHs) for each Target and OAR to a nominal standard dose at 2Gy per fraction in order to be shown together with the DV-constraints from literature, based on the LQM and radiobiological parameters, and 3) the calculation of Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) curve versus the prescribed dose to the reference target. PMID:21554675

  2. DISTANT GALAXY IDENTIFICATION TECHNIQUE IN HUBBLE FIELD

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Series of four panels that illustrate the distant-galaxy identification technique. Four panels that show (top to bottom, or right to left when rotated correctly) F814W filter, F606W filter, F450W filter, and F300W filter images, or near-infrared through near-ultraviolet images. The identified galaxy is prominent in the near-infrared image but totally absent in any of the other images. It is this spectroscopic signature that identifies this galaxy as a very distant object. Credit: Ken Lanzetta and Amos Yahil (State University of New York at Stony Brook), and NASA

  3. Frequency-offset separated oscillatory fields technique

    NASA Astrophysics Data System (ADS)

    Bezginov, N.; Vutha, A. C.; Ferchichi, I.; Storry, C. H.; Hessels, E. A.

    2015-05-01

    Improved measurements in atomic hydrogen are needed to shed light on the proton radius puzzle. We are measuring the Lamb shift in hydrogen (n = 2 ,S1 / 2 -->P1 / 2) using a frequency-offset separated oscillatory fields (FOSOF) method. The advantages of this method include its insensitivity to atomic beam intensity fluctuations and the microwave-system frequency response. We present experimental results obtained with this method, towards a new measurement of the proton charge radius. We acknowledge funding from NSERC, CFI, CRC, ORF, and NIST.

  4. Improving Soil Organic Carbon stock estimates in agricultural topsoil at a regional scale using a Stochastic Gradient Boosting technique

    NASA Astrophysics Data System (ADS)

    Schillaci, Calogero; Lombardo, Luigi; Saia, Sergio; Fantappiè, Maria; Märker, Michael; Acutis, Marco

    2016-04-01

    Agro-ecosystems have a paramount importance as a source of goods and incomes and have a highly unexpressed potential to mitigate greenhouse gasses (GHG) emission. In agro-ecosystems, Soil Organic Carbon (SOC) is recognized as the most important trait to be managed in order to maintain soil fertility and ecosystems services. Accurate laboratory analysis is indeed the best way to investigate soils. However, it is expensive and time consuming when aiming at gaining information on large areas such as an entire district or region. Remote Sensing (RS) is recently offering increasingly detailed Digital Elevation Models (DEMs) and low-cost multispectral satellite imagery. Moreover accurate worldwide climate records of the last 50 years were recently made freely available. Across Sicily, there is a strong heterogeneity of agro-ecosystems, with a dominance of field crops and orchards. In the present work, we modeled the SOC through a wide range of predictors including both ecosystem and agronomic characteristics of the soils, such as panchromatic bands, a Normalized Differenced Vegetation Index NDVI and landuse based on multispectral remote-sensed data LANDSAT ETM+7, terrain attributes derived by radar satellite data from the Shuttle Radar Topographic Mission (SRTM), as well as soil texture information and climate data record from WORLDCLIM. As dependent variable, a set of 2,891 Walkley-Black SOC and 1,049 bulk density laboratory analyses collected throughout Sicily (Italy) was used for modelling the CS stock and build the map. The Stochastic Gradient Treeboost (SGT) learning algorithm was applied to 75% of the CS stock dataset. The remaining 25% was used to validate the model. In addition, the SGT was compared to a Generalized Linear Mixed Model (GLMM). Both SGT and GLMM models show a high performance. With regards to the full model, both algorithms designated temperature and annual rainfall as fundamental predictors of CS. In addition, SGT highlighted the annual rainfall

  5. Boosted Beta Regression

    PubMed Central

    Schmid, Matthias; Wickler, Florian; Maloney, Kelly O.; Mitchell, Richard; Fenske, Nora; Mayr, Andreas

    2013-01-01

    Regression analysis with a bounded outcome is a common problem in applied statistics. Typical examples include regression models for percentage outcomes and the analysis of ratings that are measured on a bounded scale. In this paper, we consider beta regression, which is a generalization of logit models to situations where the response is continuous on the interval (0,1). Consequently, beta regression is a convenient tool for analyzing percentage responses. The classical approach to fit a beta regression model is to use maximum likelihood estimation with subsequent AIC-based variable selection. As an alternative to this established - yet unstable - approach, we propose a new estimation technique called boosted beta regression. With boosted beta regression estimation and variable selection can be carried out simultaneously in a highly efficient way. Additionally, both the mean and the variance of a percentage response can be modeled using flexible nonlinear covariate effects. As a consequence, the new method accounts for common problems such as overdispersion and non-binomial variance structures. PMID:23626706

  6. Techniques for Field Application of Lingual Ultrasound Imaging

    ERIC Educational Resources Information Center

    Gick, Bryan; Bird, Sonya; Wilson, Ian

    2005-01-01

    Techniques are discussed for using ultrasound for lingual imaging in field-related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study…

  7. Mapping Diffuse Seismicity Using Empirical Matched Field Processing Techniques

    SciTech Connect

    Wang, J; Templeton, D C; Harris, D B

    2011-01-21

    The objective of this project is to detect and locate more microearthquakes using the empirical matched field processing (MFP) method than can be detected using only conventional earthquake detection techniques. We propose that empirical MFP can complement existing catalogs and techniques. We test our method on continuous seismic data collected at the Salton Sea Geothermal Field during November 2009 and January 2010. In the Southern California Earthquake Data Center (SCEDC) earthquake catalog, 619 events were identified in our study area during this time frame and our MFP technique identified 1094 events. Therefore, we believe that the empirical MFP method combined with conventional methods significantly improves the network detection ability in an efficient matter.

  8. Bagging, boosting, and C4.5

    SciTech Connect

    Quinlan, J.R.

    1996-12-31

    Breiman`s bagging and Freund and Schapire`s boosting are recent methods for improving the predictive power of classifier learning systems. Both form a set of classifiers that are combined by voting, bagging by generating replicated bootstrap samples of the data, and boosting by adjusting the weights of training instances. This paper reports results of applying both techniques to a system that learns decision trees and testing on a representative collection of datasets. While both approaches substantially improve predictive accuracy, boosting shows the greater benefit. On the other hand, boosting also produces severe degradation on some datasets. A small change to the way that boosting combines the votes of learned classifiers reduces this downside and also leads to slightly better results on most of the datasets considered.

  9. The Lateral Decubitus Breast Boost: Description, Rationale, and Efficacy

    SciTech Connect

    Ludwig, Michelle S.; McNeese, Marsha D.; Buchholz, Thomas A.; Perkins, George H.; Strom, Eric A.

    2010-01-15

    Purpose: To describe and evaluate the modified lateral decubitus boost, a breast irradiation technique. Patients are repositioned and resimulated for electron boost to minimize the necessary depth for the electron beam and optimize target volume coverage. Methods and Materials: A total of 2,606 patients were treated with post-lumpectomy radiation at our institution between January 1, 2000, and February 1, 2008. Of these, 231 patients underwent resimulation in the lateral decubitus position with electron boost. Distance from skin to the maximal depth of target volume was measured in both the original and boost plans. Age, body mass index (BMI), boost electron energy, and skin reaction were evaluated. Results: Resimulation in the lateral decubitus position reduced the distance from skin to maximal target volume depth in all patients. Average depth reduction by repositioning was 2.12 cm, allowing for an average electron energy reduction of approximately 7 MeV. Mean skin entrance dose was reduced from about 90% to about 85% (p < 0.001). Only 14 patients (6%) experienced moist desquamation in the boost field at the end of treatment. Average BMI of these patients was 30.4 (range, 17.8-50.7). BMI greater than 30 was associated with more depth reduction by repositioning and increased risk of moist desquamation. Conclusions: The lateral decubitus position allows for a decrease in the distance from the skin to the target volume depth, improving electron coverage of the tumor bed while reducing skin entrance dose. This is a well-tolerated regimen for a patient population with a high BMI or deep tumor location.

  10. Helical Tomotherapy for Whole-Brain Irradiation With Integrated Boost to Multiple Brain Metastases: Evaluation of Dose Distribution Characteristics and Comparison With Alternative Techniques

    SciTech Connect

    Levegrün, Sabine; Pöttgen, Christoph; Wittig, Andrea; Lübcke, Wolfgang; Abu Jawad, Jehad; Stuschke, Martin

    2013-07-15

    Purpose: To quantitatively evaluate dose distribution characteristics achieved with helical tomotherapy (HT) for whole-brain irradiation (WBRT) with integrated boost (IB) to multiple brain metastases in comparison with alternative techniques. Methods and Materials: Dose distributions for 23 patients with 81 metastases treated with WBRT (30 Gy/10 fractions) and IB (50 Gy) were analyzed. The median number of metastases per patient (N{sub mets}) was 3 (range, 2-8). Mean values of the composite planning target volume of all metastases per patient (PTV{sub mets}) and of the individual metastasis planning target volume (PTV{sub ind} {sub met}) were 8.7 ± 8.9 cm{sup 3} (range, 1.3-35.5 cm{sup 3}) and 2.5 ± 4.5 cm{sup 3} (range, 0.19-24.7 cm{sup 3}), respectively. Dose distributions in PTV{sub mets} and PTV{sub ind} {sub met} were evaluated with respect to dose conformity (conformation number [CN], RTOG conformity index [PITV]), target coverage (TC), and homogeneity (homogeneity index [HI], ratio of maximum dose to prescription dose [MDPD]). The dependence of dose conformity on target size and N{sub mets} was investigated. The dose distribution characteristics were benchmarked against alternative irradiation techniques identified in a systematic literature review. Results: Mean ± standard deviation of dose distribution characteristics derived for PTV{sub mets} amounted to CN = 0.790 ± 0.101, PITV = 1.161 ± 0.154, TC = 0.95 ± 0.01, HI = 0.142 ± 0.022, and MDPD = 1.147 ± 0.029, respectively, demonstrating high dose conformity with acceptable homogeneity. Corresponding numbers for PTV{sub ind} {sub met} were CN = 0.708 ± 0.128, PITV = 1.174 ± 0.237, TC = 0.90 ± 0.10, HI = 0.140 ± 0.027, and MDPD = 1.129 ± 0.030, respectively. The target size had a statistically significant influence on dose conformity to PTV{sub mets} (CN = 0.737 for PTV{sub mets} ≤4.32 cm{sup 3} vs CN = 0.848 for PTV{sub mets} >4.32 cm{sup 3}, P=.006), in contrast to N{sub mets}. The achieved

  11. RBOOST: RIEMANNIAN DISTANCE BASED REGULARIZED BOOSTING.

    PubMed

    Liu, Meizhu; Vemuri, Baba C

    2011-03-30

    Boosting is a versatile machine learning technique that has numerous applications including but not limited to image processing, computer vision, data mining etc. It is based on the premise that the classification performance of a set of weak learners can be boosted by some weighted combination of them. There have been a number of boosting methods proposed in the literature, such as the AdaBoost, LPBoost, SoftBoost and their variations. However, the learning update strategies used in these methods usually lead to overfitting and instabilities in the classification accuracy. Improved boosting methods via regularization can overcome such difficulties. In this paper, we propose a Riemannian distance regularized LPBoost, dubbed RBoost. RBoost uses Riemannian distance between two square-root densities (in closed form) - used to represent the distribution over the training data and the classification error respectively - to regularize the error distribution in an iterative update formula. Since this distance is in closed form, RBoost requires much less computational cost compared to other regularized Boosting algorithms. We present several experimental results depicting the performance of our algorithm in comparison to recently published methods, LP-Boost and CAVIAR, on a variety of datasets including the publicly available OASIS database, a home grown Epilepsy database and the well known UCI repository. Results depict that the RBoost algorithm performs better than the competing methods in terms of accuracy and efficiency. PMID:21927643

  12. Rapid brain MRI acquisition techniques at ultra-high fields.

    PubMed

    Setsompop, Kawin; Feinberg, David A; Polimeni, Jonathan R

    2016-09-01

    Ultra-high-field MRI provides large increases in signal-to-noise ratio (SNR) as well as enhancement of several contrast mechanisms in both structural and functional imaging. Combined, these gains result in a substantial boost in contrast-to-noise ratio that can be exploited for higher-spatial-resolution imaging to extract finer-scale information about the brain. With increased spatial resolution, however, there is a concurrent increased image-encoding burden that can cause unacceptably long scan times for structural imaging and slow temporal sampling of the hemodynamic response in functional MRI - particularly when whole-brain imaging is desired. To address this issue, new directions of imaging technology development - such as the move from conventional 2D slice-by-slice imaging to more efficient simultaneous multislice (SMS) or multiband imaging (which can be viewed as "pseudo-3D" encoding) as well as full 3D imaging - have provided dramatic improvements in acquisition speed. Such imaging paradigms provide higher SNR efficiency as well as improved encoding efficiency. Moreover, SMS and 3D imaging can make better use of coil sensitivity information in multichannel receiver arrays used for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher in these imaging acquisition schemes, with low image artifact levels and high SNR. Here we review the latest developments of SMS and 3D imaging methods and related technologies at ultra-high field for rapid high-resolution functional and structural imaging of the brain. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26835884

  13. Augmented Replicative Capacity of the Boosting Antigen Improves the Protective Efficacy of Heterologous Prime-Boost Vaccine Regimens

    PubMed Central

    Penaloza-MacMaster, Pablo; Teigler, Jeffrey E.; Obeng, Rebecca C.; Kang, Zi H.; Provine, Nicholas M.; Parenteau, Lily; Blackmore, Stephen; Ra, Joshua; Borducchi, Erica N.

    2014-01-01

    ABSTRACT Prime-boost immunization regimens have proven efficacious at generating robust immune responses. However, whether the level of replication of the boosting antigen impacts the magnitude and protective efficacy of vaccine-elicited immune responses remains unclear. To evaluate this, we primed mice with replication-defective adenovirus vectors expressing the lymphocytic choriomeningitis virus (LCMV) glycoprotein (GP), followed by boosting with either LCMV Armstrong, which is rapidly controlled, or LCMV CL-13, which leads to a more prolonged exposure to the boosting antigen. Although priming of naive mice with LCMV CL-13 normally results in T cell exhaustion and establishment of chronic infection, boosting with CL-13 resulted in potent recall CD8 T cell responses that were greater than those following boosting with LCMV Armstrong. Furthermore, following the CL-13 boost, a greater number of anamnestic CD8 T cells localized to the lymph nodes, exhibited granzyme B expression, and conferred improved protection against Listeria and vaccinia virus challenges compared with the Armstrong boost. Overall, our findings suggest that the replicative capacity of the boosting antigen influences the protective efficacy afforded by prime-boost vaccine regimens. These findings are relevant for optimizing vaccine candidates and suggest a benefit of robustly replicating vaccine vectors. IMPORTANCE The development of optimal prime-boost vaccine regimens is a high priority for the vaccine development field. In this study, we compared two boosting antigens with different replicative capacities. Boosting with a more highly replicative vector resulted in augmented immune responses and improved protective efficacy. PMID:24648461

  14. Technique for Predicting the RF Field Strength Inside an Enclosure

    NASA Technical Reports Server (NTRS)

    Hallett, M.; Reddell, J.

    1998-01-01

    This Memorandum presents a simple analytical technique for predicting the RF electric field strength inside an enclosed volume in which radio frequency radiation occurs. The technique was developed to predict the radio frequency (RF) field strength within a launch vehicle's fairing from payloads launched with their telemetry transmitters radiating and to the impact of the radiation on the vehicle and payload. The RF field strength is shown to be a function of the surface materials and surface areas. The method accounts for RF energy losses within exposed surfaces, through RF windows, and within multiple layers of dielectric materials which may cover the surfaces. This Memorandum includes the rigorous derivation of all equations and presents examples and data to support the validity of the technique.

  15. Analysis techniques used on field degraded photovoltaic modules

    SciTech Connect

    Hund, T.D.; King, D.L.

    1995-09-01

    Sandia National Laboratory`s PV System Components Department performs comprehensive failure analysis of photovoltaic modules after extended field exposure at various sites around the world. A full spectrum of analytical techniques are used to help identify the causes of degradation. The techniques are used to make solder fatigue life predictions for PV concentrator modules, identify cell damage or current mismatch, and measure the adhesive strength of the module encapsulant.

  16. Use of Field Research Sites to Teach Field Techniques in Graduate Level Soil Physics.

    ERIC Educational Resources Information Center

    Cassel, D. K.

    1986-01-01

    Describes how a field research site provides grauduate soil physics students with practical field-oriented experiences. Explains the structure of the course and the nature of the course's investigations. Assesses the advantages and obstacles associated with the field research technique. (ML)

  17. Teaching Avalanche Safety Courses: Instructional Techniques and Field Exercises.

    ERIC Educational Resources Information Center

    Watters, Ron

    This paper discusses course structure, teaching techniques, and field exercises for enhancing winter travelers' avalanche knowledge and skills. In two class sessions, the course typically consists of a historical perspective; a section on snow physics (clouds, types of snow crystals, effects of riming, identification of precipitated snow crystals,…

  18. ASD FieldSpec Calibration Setup and Techniques

    NASA Technical Reports Server (NTRS)

    Olive, Dan

    2001-01-01

    This paper describes the Analytical Spectral Devices (ASD) Fieldspec Calibration Setup and Techniques. The topics include: 1) ASD Fieldspec FR Spectroradiometer; 2) Components of Calibration; 3) Equipment list; 4) Spectral Setup; 5) Spectral Calibration; 6) Radiometric and Linearity Setup; 7) Radiometric setup; 8) Datadets Required; 9) Data files; and 10) Field of View Measurement. This paper is in viewgraph form.

  19. Development of Improved Oil Field Waste Injection Disposal Techniques

    SciTech Connect

    Terralog Technologies USA Inc.

    2001-12-17

    The goals of this DOE sponsored project are to: (1) assemble and analyze a comprehensive database of past waste injection operations; (2) develop improved diagnostic techniques for monitoring fracture growth and formation changes; (3) develop operating guidelines to optimize daily operations and ultimate storage capacity of the target formation; and (4) to test these improved models and guidelines in the field.

  20. Development of Improved Oil Field Waste Injection Disposal Techniques

    SciTech Connect

    Terralog Technologies

    2002-11-25

    The goals of this project have was to: (1) assemble and analyze a comprehensive database of past waste injection operations; (2) develop improved diagnostic techniques for monitoring fracture growth and formation changes; (3) develop operating guidelines to optimize daily operations and ultimate storage capacity of the target formation; and (4) to apply these improved models and guidelines in the field.

  1. An objective analysis technique for extrapolating tidal fields

    NASA Technical Reports Server (NTRS)

    Sanchez, B. V.

    1984-01-01

    An interpolation technique which allows accurate extrapolation of tidal height fields in the ocean basins by making use of selected satellite altimetry measurements and/or conventional gauge measurements was developed and tested. A normal mode solution for the Atlantic and Indian Oceans was obtained by means of a finite difference grid. Normal mode amplitude maps are presented.

  2. New techniques in 3D scalar and vector field visualization

    SciTech Connect

    Max, N.; Crawfis, R.; Becker, B.

    1993-05-05

    At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

  3. A stochastic filtering technique for fluid flow velocity fields tracking.

    PubMed

    Cuzol, Anne; Mémin, Etienne

    2009-07-01

    In this paper, we present a method for the temporal tracking of fluid flow velocity fields. The technique we propose is formalized within a sequential Bayesian filtering framework. The filtering model combines an Itô diffusion process coming from a stochastic formulation of the vorticity-velocity form of the Navier-Stokes equation and discrete measurements extracted from the image sequence. In order to handle a state space of reasonable dimension, the motion field is represented as a combination of adapted basis functions, derived from a discretization of the vorticity map of the fluid flow velocity field. The resulting nonlinear filtering problem is solved with the particle filter algorithm in continuous time. An adaptive dimensional reduction method is applied to the filtering technique, relying on dynamical systems theory. The efficiency of the tracking method is demonstrated on synthetic and real-world sequences. PMID:19443925

  4. TH-C-12A-06: Feasibility of a MLC-Based Inversely Optimized Multi-Field Grid Therapy Technique

    SciTech Connect

    Jin, J; Zhao, B; Huang, Y; Kim, J; Qin, Y; Wen, N; Ryu, S; Chetty, I

    2014-06-15

    Purpose: Grid therapy (GT), which generates highly spatially modulated dose distributions, can deliver single- or hypo-fractionated radiotherapy for large tumors without causing significant toxicities. GT may be applied in combination with immunotherapy, in light of recent preclinical data of synergetic interaction between radiotherapy and immunotherapy. However, conventional GT uses only one field, which does not have the advantage of multi-fields in 3D conformal-RT or IMRT. We have proposed a novel MLC-based, inverse-planned multi-field 3D GT technique. This study aims to test its deliverability and dosimetric accuracy. Methods: A lattice of small spheres was created as the boost volume within a large target. A simultaneous boost IMRT plan with 8-Gy to the target and 20-Gy to the boost volume was generated in the Eclipse treatment planning system (AAA v10) with a HD120 MLC. Nine beams were used, and the gantry and couch angles were selected so that the spheres were perfectly aligned in every beams eye view. The plan was mapped to a phantom with dose scaled. EBT3 films were calibrated and used to measure the delivered dose. Results: The IMRT plan generated a highly spatially modulated dose distribution in the target. D95%, D50%, D5% for the spheres and the targets in Gy were 18.5, 20.0, 21.4 and 7.9, 9.8, 16.1, respectively. D50% for a 1cm ring 1cm outside the target was 2.9-Gy. Film dosimetry showed good agreement between calculated and delivered dose, with an overall gamma passing rate of 99.6% (3%/1mm). The point dose differences for different spheres varied from 1–6%. Conclusion: We have demonstrated the deliverability and dose calculation accuracy of the MLC-based inversely optimized multi-field GT technique, which achieved a brachytherapy-like dose distribution. Single-fraction high dose can be delivered to the spheres in a large target with minimal dose to the surrounding normal tissue.

  5. Semantic Data And Visualization Techniques Applied To Geologic Field Mapping

    NASA Astrophysics Data System (ADS)

    Houser, P. I. Q.; Royo-Leon, M.; Munoz, R.; Estrada, E.; Villanueva-Rosales, N.; Pennington, D. D.

    2015-12-01

    Geologic field mapping involves the use of technology before, during, and after visiting a site. Geologists utilize hardware such as Global Positioning Systems (GPS) connected to mobile computing platforms such as tablets that include software such as ESRI's ArcPad and other software to produce maps and figures for a final analysis and report. Hand written field notes contain important information and drawings or sketches of specific areas within the field study. Our goal is to collect and geo-tag final and raw field data into a cyber-infrastructure environment with an ontology that allows for large data processing, visualization, sharing, and searching, aiding in connecting field research with prior research in the same area and/or aid with experiment replication. Online searches of a specific field area return results such as weather data from NOAA and QuakeML seismic data from USGS. These results that can then be saved to a field mobile device and searched while in the field where there is no Internet connection. To accomplish this we created the GeoField ontology service using the Web Ontology Language (OWL) and Protégé software. Advanced queries on the dataset can be made using reasoning capabilities can be supported that go beyond a standard database service. These improvements include the automated discovery of data relevant to a specific field site and visualization techniques aimed at enhancing analysis and collaboration while in the field by draping data over mobile views of the site using augmented reality. A case study is being performed at University of Texas at El Paso's Indio Mountains Research Station located near Van Horn, Texas, an active multi-disciplinary field study site. The user can interactively move the camera around the study site and view their data digitally. Geologist's can check their data against the site in real-time and improve collaboration with another person as both parties have the same interactive view of the data.

  6. The phase field technique for modeling multiphase materials

    NASA Astrophysics Data System (ADS)

    Singer-Loginova, I.; Singer, H. M.

    2008-10-01

    This paper reviews methods and applications of the phase field technique, one of the fastest growing areas in computational materials science. The phase field method is used as a theory and computational tool for predictions of the evolution of arbitrarily shaped morphologies and complex microstructures in materials. In this method, the interface between two phases (e.g. solid and liquid) is treated as a region of finite width having a gradual variation of different physical quantities, i.e. it is a diffuse interface model. An auxiliary variable, the phase field or order parameter \\phi(\\vec{x}) , is introduced, which distinguishes one phase from the other. Interfaces are identified by the variation of the phase field. We begin with presenting the physical background of the phase field method and give a detailed thermodynamical derivation of the phase field equations. We demonstrate how equilibrium and non-equilibrium physical phenomena at the phase interface are incorporated into the phase field methods. Then we address in detail dendritic and directional solidification of pure and multicomponent alloys, effects of natural convection and forced flow, grain growth, nucleation, solid-solid phase transformation and highlight other applications of the phase field methods. In particular, we review the novel phase field crystal model, which combines atomistic length scales with diffusive time scales. We also discuss aspects of quantitative phase field modeling such as thin interface asymptotic analysis and coupling to thermodynamic databases. The phase field methods result in a set of partial differential equations, whose solutions require time-consuming large-scale computations and often limit the applicability of the method. Subsequently, we review numerical approaches to solve the phase field equations and present a finite difference discretization of the anisotropic Laplacian operator.

  7. FloatBoost learning and statistical face detection.

    PubMed

    Li, Stan Z; Zhang, ZhenQiu

    2004-09-01

    A novel learning procedure, called FloatBoost, is proposed for learning a boosted classifier for achieving the minimum error rate. FloatBoost learning uses a backtrack mechanism after each iteration of AdaBoost learning to minimize the error rate directly, rather than minimizing an exponential function of the margin as in the traditional AdaBoost algorithms. A second contribution of the paper is a novel statistical model for learning best weak classifiers using a stagewise approximation of the posterior probability. These novel techniques lead to a classifier which requires fewer weak classifiers than AdaBoost yet achieves lower error rates in both training and testing, as demonstrated by extensive experiments. Applied to face detection, the FloatBoost learning method, together with a proposed detector pyramid architecture, leads to the first real-time multiview face detection system reported. PMID:15742888

  8. Interferometric resolution boosting for spectrographs

    SciTech Connect

    Erskine, D J; Edelstein, J

    2004-05-25

    Externally dispersed interferometry (EDI) is a technique for enhancing the performance of spectrographs for wide bandwidth high resolution spectroscopy and Doppler radial velocimetry. By placing a small angle-independent interferometer near the slit of a spectrograph, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moir{acute e} pattern, which manifests high detailed spectral information heterodyned down to detectably low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry. Previous demonstrations of {approx}2.5x resolution boost used an interferometer having a single fixed delay. We report new data indicating {approx}6x Gaussian resolution boost (140,000 from a spectrograph with 25,000 native resolving power), taken by using multiple exposures at widely different interferometer delays.

  9. The Electron Drift Technique for Measuring Electric and Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Paschmann, G.; McIlwain, C. E.; Quinn, J. M.; Torbert, R. B.; Whipple, E. C.; Christensen, John (Technical Monitor)

    1998-01-01

    The electron drift technique is based on sensing the drift of a weak beam of test electrons that is caused by electric fields and/or gradients in the magnetic field. These quantities can, by use of different electron energies, in principle be determined separately. Depending on the ratio of drift speed to magnetic field strength, the drift velocity can be determined either from the two emission directions that cause the electrons to gyrate back to detectors placed some distance from the emitting guns, or from measurements of the time of flight of the electrons. As a by-product of the time-of-flight measurements, the magnetic field strength is also determined. The paper describes strengths and weaknesses of the method as well as technical constraints.

  10. Dark-field Z-scan imaging technique

    NASA Astrophysics Data System (ADS)

    Wang, Hongzhen; Cassagne, Christophe; Leblond, Hervé; Boudebs, Georges

    2016-05-01

    We report on Dark-Field Z-scan (DFZ-scan) as a new imaging technique combining Z-scan method with Dark-field microscopy in order to measure optical refraction nonlinearity. Numerical and experimental results are provided to validate this concept. The image of the induced phase shift is spatially resolved without introducing a complex interferometric setup. Moreover, the experimental results show almost 3 times increase of the sensitivity when compared to the conventional Z-scan method. New perspective of microscope laser scanning is introduced.

  11. Data acquisition and preprocessing techniques for remote sensing field research

    NASA Technical Reports Server (NTRS)

    Biehl, L. L.; Robinson, B. F.

    1983-01-01

    A crops and soils data base has been developed at Purdue University's Laboratory for Applications of Remote Sensing using spectral and agronomic measurements made by several government and university researchers. The data are being used to (1) quantitatively determine the relationships of spectral and agronomic characteristics of crops and soils, (2) define future sensor systems, and (3) develop advanced data analysis techniques. Researchers follow defined data acquisition and preprocessing techniques to provide fully annotated and calibrated sets of spectral, agronomic, and meteorological data. These procedures enable the researcher to combine his data with that acquired by other researchers for remote sensing research. The key elements or requirements for developing a field research data base of spectral data that can be transported across sites and years are appropriate experiment design, accurate spectral data calibration, defined field procedures, and through experiment documentation.

  12. Time Delay Integration: A Wide-Field Survey Technique

    NASA Astrophysics Data System (ADS)

    Lapointe, Robert; Hill, E.; Leimer, L.; McMillian, K.; Miller, A.; Prindle, A.

    2009-05-01

    The Advanced Placement Physics class of Orange Lutheran High School has conducted a survey-imaging pro-ject using a Time Delay Integration (TDI) technique. TDI enables very wide-field images to be collected in the form of long strips of the sky. A series of five consecutive nights were captured, calibrated and compared to re-veal possible transient phenomena such as supernovae, asteroids, and other events that have a noticeable change over 24-hour intervals.

  13. Novel Techniques for Pulsed Field Gradient NMR Measurements

    NASA Astrophysics Data System (ADS)

    Brey, William Wallace

    Pulsed field gradient (PFG) techniques now find application in multiple quantum filtering and diffusion experiments as well as in magnetic resonance imaging and spatially selective spectroscopy. Conventionally, the gradient fields are produced by azimuthal and longitudinal currents on the surfaces of one or two cylinders. Using a series of planar units consisting of azimuthal and radial current elements spaced along the longitudinal axis, we have designed gradient coils having linear regions that extend axially nearly to the ends of the coil and to more than 80% of the inner radius. These designs locate the current return paths on a concentric cylinder, so the coils are called Concentric Return Path (CRP) coils. Coils having extended linear regions can be made smaller for a given sample size. Among the advantages that can accrue from using smaller coils are improved gradient strength and switching time, reduced eddy currents in the absence of shielding, and improved use of bore space. We used an approximation technique to predict the remaining eddy currents and a time-domain model of coil performance to simulate the electrical performance of the CRP coil and several reduced volume coils of more conventional design. One of the conventional coils was designed based on the time-domain performance model. A single-point acquisition technique was developed to measure the remaining eddy currents of the reduced volume coils. Adaptive sampling increases the dynamic range of the measurement. Measuring only the center of the stimulated echo removes chemical shift and B_0 inhomogeneity effects. The technique was also used to design an inverse filter to remove the eddy current effects in a larger coil set. We added pulsed field gradient and imaging capability to a 7 T commercial spectrometer to perform neuroscience and embryology research and used it in preliminary studies of binary liquid mixtures separating near a critical point. These techniques and coil designs will find

  14. Applying field mapping refractive beam shapers to improve holographic techniques

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Williams, Gavin; McWilliam, Richard; Laskin, Vadim

    2012-03-01

    Performance of various holographic techniques can be essentially improved by homogenizing the intensity profile of the laser beam with using beam shaping optics, for example, the achromatic field mapping refractive beam shapers like πShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flattop one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with several laser sources with different wavelengths simultaneously. Applying of these beam shapers brings serious benefits to the Spatial Light Modulator based techniques like Computer Generated Holography or Dot-Matrix mastering of security holograms since uniform illumination of an SLM allows simplifying mathematical calculations and increasing predictability and reliability of the imaging results. Another example is multicolour Denisyuk holography when the achromatic πShaper provides uniform illumination of a field at various wavelengths simultaneously. This paper will describe some design basics of the field mapping refractive beam shapers and optical layouts of their applying in holographic systems. Examples of real implementations and experimental results will be presented as well.

  15. Performance Boosting Additive

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mainstream Engineering Corporation was awarded Phase I and Phase II contracts from Goddard Space Flight Center's Small Business Innovation Research (SBIR) program in early 1990. With support from the SBIR program, Mainstream Engineering Corporation has developed a unique low cost additive, QwikBoost (TM), that increases the performance of air conditioners, heat pumps, refrigerators, and freezers. Because of the energy and environmental benefits of QwikBoost, Mainstream received the Tibbetts Award at a White House Ceremony on October 16, 1997. QwikBoost was introduced at the 1998 International Air Conditioning, Heating, and Refrigeration Exposition. QwikBoost is packaged in a handy 3-ounce can (pressurized with R-134a) and will be available for automotive air conditioning systems in summer 1998.

  16. Evaluation of Field-in-Field Technique for Total Body Irradiation

    SciTech Connect

    Onal, Cem; Sonmez, Aydan; Arslan, Gungor; Sonmez, Serhat; Efe, Esma; Oymak, Ezgi

    2012-08-01

    Purpose: To evaluate the clinical use of a field-in-field (FIF) technique for total body irradiation (TBI) using a treatment-planning system (TPS) and to verify TPS results with in vivo dose measurements using metal-oxide-semiconductor field-effect transistor (MOSFET) detectors. Methods and Materials: Clinical and dosimetric data of 10 patients treated with TBI were assessed. Certain radiation parameters were measured using homogenous and regular phantoms at an extended distance of 380 cm, and the results were compared with data from a conventional standard distance of 100 cm. Additionally, dosimetric validation of TPS doses was performed with a Rando phantom using manual calculations. A three-dimensional computed tomography plan was generated involving 18-MV photon beams with a TPS for both open-field and FIF techniques. The midline doses were measured at the head, neck, lung, umbilicus, and pelvis for both open-field and FIF techniques. Results: All patients received planned TBI using the FIF technique with 18-MV photon energies and 2 Gy b.i.d. on 3 consecutive days. The difference in tissue maximum ratios between the extended and conventional distances was <2%. The mean deviation of manual calculations compared with TPS data was +1.6% (range, 0.1-2.4%). A homogenous dose distribution was obtained with 18-MV photon beams using the FIF technique. The mean lung dose for the FIF technique was 79.2% (9.2 Gy; range, 8.8-9.7 Gy) of the prescribed dose. The MOSFET readings and TPS doses in the body were similar (percentage difference range, -0.5% to 2.5%) and slightly higher in the shoulder and lung (percentage difference range, 4.0-5.5%). Conclusion: The FIF technique used for TBI provides homogenous dose distribution and is feasible, simple, and spares time compared with more-complex techniques. The TPS doses were similar to the midline doses obtained from MOSFET readings.

  17. Near-Field Source Localization by Using Focusing Technique

    NASA Astrophysics Data System (ADS)

    He, Hongyang; Wang, Yide; Saillard, Joseph

    2008-12-01

    We discuss two fast algorithms to localize multiple sources in near field. The symmetry-based method proposed by Zhi and Chia (2007) is first improved by implementing a search-free procedure for the reduction of computation cost. We present then a focusing-based method which does not require symmetric array configuration. By using focusing technique, the near-field signal model is transformed into a model possessing the same structure as in the far-field situation, which allows the bearing estimation with the well-studied far-field methods. With the estimated bearing, the range estimation of each source is consequently obtained by using 1D MUSIC method without parameter pairing. The performance of the improved symmetry-based method and the proposed focusing-based method is compared by Monte Carlo simulations and with Crammer-Rao bound as well. Unlike other near-field algorithms, these two approaches require neither high-computation cost nor high-order statistics.

  18. Field tests of laser ranging using PRBS modulation techniques

    NASA Astrophysics Data System (ADS)

    Kovalik, J.; Wilson, K.; Wright, M.; Williamson, W.

    2011-06-01

    We have developed and tested an optical ranging system using a Pseudo-Random Bit Stream (PRBS) modulation technique. The optical transceiver consisted of an infrared laser transmitter co-aligned with a receiver telescope. The infrared laser beam was propagated to a retro-reflector and then received by a detector coupled to the telescope. The transceiver itself was mounted on a gimbal that could actively track moving targets through a camera that was bore sighted with the optical detector. The detected optical signal was processed in real time to produce a range measurement with sub mm accuracy. This system was tested in the field using both stationary and moving targets up to 5 km away. Ranging measurements to an aircraft were compared with results obtained by differential GPS (Global Positioning System) techniques.

  19. Critical field measurements in superconductors using ac inductive techniques

    NASA Astrophysics Data System (ADS)

    Campbell, S. A.; Ketterson, J. B.; Crabtree, G. W.

    1983-09-01

    The ac in-phase and out-of-phase response of type II superconductors is discussed in terms of dc magnetization curves. Hysteresis in the dc magnetization is shown to lead to a dependence of the ac response on the rate at which an external field is swept. This effect allows both Hc1 and Hc2 to be measured by ac techniques. A relatively simple mutual inductance bridge for making such measurements is described in the text, and factors affecting bridge sensitivity are discussed in the Appendix. Data for the magnetic superconductor ErRh4B4 obtained using this bridge are reported.

  20. Mean field bipartite spin models treated with mechanical techniques

    NASA Astrophysics Data System (ADS)

    Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Pizzoferrato, Andrea; Tantari, Daniele

    2014-03-01

    Inspired by a continuously increasing interest in modeling and framing complex systems in a thermodynamic rationale, in this paper we continue our investigation in adapting well-known techniques (originally stemmed in fields of physics and mathematics far from the present) for solving for the free energy of mean field spin models in a statistical mechanics scenario. Focusing on the test cases of bipartite spin systems embedded with all the possible interactions (self and reciprocal), we show that both the fully interacting bipartite ferromagnet, as well as the spin glass counterpart, at least at the replica symmetric level, can be solved via the fundamental theorem of calculus, trough an analogy with the Hamilton-Jacobi theory and lastly with a mapping to a Fourier diffusion problem. All these technologies are shown symmetrically for ferromagnets and spin-glasses in full details and contribute as powerful tools in the investigation of complex systems.

  1. Where boosted significances come from

    NASA Astrophysics Data System (ADS)

    Plehn, Tilman; Schichtel, Peter; Wiegand, Daniel

    2014-03-01

    In an era of increasingly advanced experimental analysis techniques it is crucial to understand which phase space regions contribute a signal extraction from backgrounds. Based on the Neyman-Pearson lemma we compute the maximum significance for a signal extraction as an integral over phase space regions. We then study to what degree boosted Higgs strategies benefit ZH and tt¯H searches and which transverse momenta of the Higgs are most promising. We find that Higgs and top taggers are the appropriate tools, but would profit from a targeted optimization towards smaller transverse momenta. MadMax is available as an add-on to MadGraph 5.

  2. CCD mosaic technique for large-field digital mammography

    SciTech Connect

    Jalink, A.; McAdoo, J.; Halama, G.; Liu, H.

    1996-06-01

    The authors present a novel technique for large-field digital mammography. The instrument uses a mosaic of electronic digital imaging [charge coupled device (CCD)] arrays, novel area scanning, and a radiation exposure and scatter reducing mechanism. The imaging arrays are mounted on a carrier platform in a checker-board pattern mosaic. To fill in the gaps between array-active areas the platform is repositioned three times and four X-ray exposures are made. The multiple image areas are then recombined by a digital computer to produce a composite image of the entire region. To reduce X-ray scatter and exposure, a lead aperture plate is interposed between X-ray source and patient. The aperture plate has a mosaic of square holes in alignment with the imaging array pattern and the plate is repositioned in synchronism with the carrier platform. The authors discuss proof-of-concept testing demonstrating technical feasibility of their approach. The instrument should be suitable for incorporation into standard mammography units. Unique features of the new technique are: large field coverage (18 x 24 cm); high spatial resolution (14--17 lp/mm); scatter rejection; and excellent contrast characteristics and lesion detectability under clinical conditions.

  3. Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

    The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

  4. Low-Field Accelerator Structure Couplers and Design Techniques

    SciTech Connect

    Nantista, C

    2004-07-29

    Recent experience with X-band accelerator structure development has shown the rf input coupler to be the region most prone to rf breakdown and degradation, effectively limiting the operating gradient. A major factor in this appears to be high magnetic fields at the sharp edges of the coupling irises. As a first response to this problem, couplers with rounded and thickened iris horns have been employed and successfully tested at high power. To further reduce fields for higher power flow, conceptually new coupler designs have been developed, in which power is coupled through the broadwall of the feed waveguide, rather than through terminating irises. A 'mode launcher' coupler, which launches the TM{sub 01} mode in circular waveguide before coupling through a matching cell into the main structure, has been tested with great success. With peak surface fields below those in the body of the structure, this coupler represented a break-through in the NLC structure program. The design of this coupler and of variations which use beamline space more efficiently are described here. The latter include a coupler in which power passes directly through an iris in the broad wall of the rectangular waveguide into a matching cell, also successfully implemented, and a variation which makes the waveguide itself an accelerating cell. The authors also discuss in some detail a couple of techniques for matching such couplers to travelling-wave structures using a field solver. The first exploits the cell number independence of a travelling-wave match, and the second optimizes using the fields of an internally driven structure.

  5. Stereotactic Body Radiation Therapy Boost in Locally Advanced Pancreatic Cancer

    SciTech Connect

    Seo, Young Seok; Kim, Mi-Sook; Yoo, Sung Yul; Cho, Chul Koo; Yang, Kwang Mo; Yoo, Hyung Jun; Choi, Chul Won; Lee, Dong Han; Kim, Jin; Kim, Min Suk; Kang, Hye Jin; Kim, YoungHan

    2009-12-01

    Purpose: To investigate the clinical application of a stereotactic body radiation therapy (SBRT) boost in locally advanced pancreatic cancer patients with a focus on local efficacy and toxicity. Methods and Materials: We retrospectively reviewed 30 patients with locally advanced and nonmetastatic pancreatic cancer who had been treated between 2004 and 2006. Follow-up duration ranged from 4 to 41 months (median, 14.5 months). A total dose of 40 Gy was delivered in 20 fractions using a conventional three-field technique, and then a single fraction of 14, 15, 16, or 17 Gy SBRT was administered as a boost without a break. Twenty-one patients received chemotherapy. Overall and local progression-free survival were calculated and prognostic factors were evaluated. Results: One-year overall survival and local progression-free survival rates were 60.0% and 70.2%, respectively. One patient (3%) developed Grade 4 toxicity. Carbohydrate antigen 19-9 response was found to be an independent prognostic factor for survival. Conclusions: Our findings indicate that a SBRT boost provides a safe means of increasing radiation dose. Based on the results of this study, we recommend that a well controlled Phase II study be conducted on locally advanced pancreatic cancer.

  6. Magnetic field measurement techniques with heavy ion beam probes

    SciTech Connect

    Crowley, T.P.

    1988-08-01

    Spatially (0.1 cm/sup 3/) and temporally (1 ..mu..s) resolved magnetic field measurement techniques using a heavy ion beam probe as a test particle source are described. The measurement of both steady-state and time-varying fields is discussed. The plasma flux function can be determined by measuring the toroidal velocity of the beam ion in an axisymmetric device, because the canonical angular momentum of a particle, P/sub phi/ = qpsi+M..nu../sub phi/R, is conserved in an axisymmetric system. Corrections due to nonaxisymmetry can be significant in tokamaks and must be taken into account for the current profile and fluctuation measurements. The requirements and design of a toroidal velocity detector are discussed. The signals expected in experiments using the Texas Experimental Tokamak (TEXT) heavy ion beam probe with a velocity detector have been calculated, and they are at least two orders of magnitude higher than the amplifier noise for dc measurements of poloidal and ergodic magnetic limiter fields and for sawtooth and MHD oscillations. Low-level turbulence is expected to produce signals below the noise level.

  7. A magnetic field measurement technique using a miniature transducer

    NASA Technical Reports Server (NTRS)

    Fales, C. L., Jr.; Breckenridge, R. A.; Debnam, W. J., Jr.

    1974-01-01

    The development, fabrication, and application of a magnetometer are described. The magnetometer has a miniature transducer and is capable of automatic scanning. The magnetometer described here is capable of detecting static magnetic fields as low as 1.6 A/m and its transducer has an active area 0.64 mm by 0.76 mm. Thin and rugged, the transducer uses wire, 0.05 mm in diameter, which is plated with a magnetic film, enabling measurement of transverse magnetic fields as close as 0.08 mm from a surface. The magnetometer, which is simple to operate and has a fast response, uses an inexpensive clip-on milliammeter (commonly found in most laboratories) for driving and processing the electrical signals and readout. A specially designed transducer holding mechanism replaces the XY recorder ink pen; this mechanism provides the basis for an automatic scanning technique. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated-wire memory planes and regions of magnetic activity in geological rock specimens.

  8. Comprehensive review of high power factor ac-dc boost converters for PFC applications

    NASA Astrophysics Data System (ADS)

    De Castro Pereira, Dênis; Da Silva, Márcio Renato; Mateus Silva, Elder; Lessa Tofoli, Fernando

    2015-08-01

    High power factor rectifiers have been consolidated as an effective solution to improve power quality indices in terms of input power factor correction, reduction in the total harmonic distortion of the input current and also regulated dc voltages. Within this context, this subject has motivated the introduction of numerous converter topologies based on classic dc-dc structures associated with novel control techniques, thus leading to the manufacturing of dedicated integrated circuits that allow high input power factor by adding a front-end stage to switch-mode converters. In particular, boost converters in continuous current mode (CCM) are widely employed since they allow obtaining minimised electromagnetic interference levels. This work is concerned with a literature review involving relevant ac-dc single-phase boost-based topologies with high input power factor. The evolution of aspects regarding the conventional boost converter is shown in terms of improved characteristics inherent to other ac-dc boost converters. Additionally, the work intends to be a fast and concise reference to single-phase ac-dc boost converters operating in CCM for engineers, researchers and experts in the field of power electronics by properly analysing and comparing the aforementioned rectifiers.

  9. Pattern recognition techniques and the measurement of solar magnetic fields

    NASA Astrophysics Data System (ADS)

    Lopez Ariste, Arturo; Rees, David E.; Socas-Navarro, Hector; Lites, Bruce W.

    2001-11-01

    Measuring vector magnetic fields in the solar atmosphere using the profiles of the Stokes parameters of polarized spectral lines split by the Zeeman effect is known as Stokes Inversion. This inverse problem is usually solved by least-squares fitting of the Stokes profiles. However least-squares inversion is too slow for the new generation of solar instruments (THEMIS, SOLIS, Solar-B, ...) which will produce an ever-growing flood of spectral data. The solar community urgently requires a new approach capable of handling this information explosion, preferably in real-time. We have successfully applied pattern recognition and machine learning techniques to tackle this problem. For example, we have developed PCA-inversion, a database search technique based on Principal Component Analysis of the Stokes profiles. Search is fast because it is carried out in low dimensional PCA feature space, rather than the high dimensional space of the spectral signals. Such a data compression approach has been widely used for search and retrieval in many areas of data mining. PCA-inversion is the basis of a new inversion code called FATIMA (Fast Analysis Technique for the Inversion of Magnetic Atmospheres). Tests on data from HAO's Advanced Stokes Polarimeter show that FATIMA isover two orders of magnitude faster than least squares inversion. Initial tests on an alternative code (DIANNE - Direct Inversion based on Artificial Neural NEtworks) show great promise of achieving real-time performance. In this paper we present the latest achievements of FATIMA and DIANNE, two powerful examples of how pattern recognition techniques can revolutionize data analysis in astronomy.

  10. Heterologous prime-boost vaccination.

    PubMed

    Lu, Shan

    2009-06-01

    An effective vaccine usually requires more than one time immunization in the form of prime-boost. Traditionally the same vaccines are given multiple times as homologous boosts. New findings suggested that prime-boost can be done with different types of vaccines containing the same antigens. In many cases such heterologous prime-boost can be more immunogenic than homologous prime-boost. Heterologous prime-boost represents a new way of immunization and will stimulate better understanding on the immunological basis of vaccines. PMID:19500964

  11. Online Bagging and Boosting

    NASA Technical Reports Server (NTRS)

    Oza, Nikunji C.

    2005-01-01

    Bagging and boosting are two of the most well-known ensemble learning methods due to their theoretical performance guarantees and strong experimental results. However, these algorithms have been used mainly in batch mode, i.e., they require the entire training set to be available at once and, in some cases, require random access to the data. In this paper, we present online versions of bagging and boosting that require only one pass through the training data. We build on previously presented work by presenting some theoretical results. We also compare the online and batch algorithms experimentally in terms of accuracy and running time.

  12. Evolutionary Based Techniques for Fault Tolerant Field Programmable Gate Arrays

    NASA Technical Reports Server (NTRS)

    Larchev, Gregory V.; Lohn, Jason D.

    2006-01-01

    The use of SRAM-based Field Programmable Gate Arrays (FPGAs) is becoming more and more prevalent in space applications. Commercial-grade FPGAs are potentially susceptible to permanently debilitating Single-Event Latchups (SELs). Repair methods based on Evolutionary Algorithms may be applied to FPGA circuits to enable successful fault recovery. This paper presents the experimental results of applying such methods to repair four commonly used circuits (quadrature decoder, 3-by-3-bit multiplier, 3-by-3-bit adder, 440-7 decoder) into which a number of simulated faults have been introduced. The results suggest that evolutionary repair techniques can improve the process of fault recovery when used instead of or as a supplement to Triple Modular Redundancy (TMR), which is currently the predominant method for mitigating FPGA faults.

  13. Strengthened electric field technique implemented on CZT detectors

    NASA Astrophysics Data System (ADS)

    Fu, Jianqiang; Li, Yulan; Zhang, Lan; Du, Yingshuai; Yang, Yigang; Liu, Yinong; Niu, Libo; Jiang, Hao; Liu, Yilin; Li, Jun; Zhang, Wei; Liu, Yanqing; Li, Yuanjing

    2015-01-01

    This paper presents the development of a simple electrode structure which only requires a simple readout and is suitable for a large cube CZT crystal, such as a 10×10×10 mm3 crystal. A technique named the strengthened electric field (SEF) is investigated in detail and implemented to improve the performance of the detector. Signal processing was also studied to demonstrate its feasibility to further improve the detector's performance. A SEF line anode (SEFLA) prototype and an SEF point anode (SEFPA) prototype were designed, fabricated and tested. Experimental results demonstrated the effectiveness of the SEF technique. The SEFLA detector achieved an energy resolution of 1.6% (FWHM)@662 keV with 4.0 keV noise (FWHM) and SEFPA 1.8% with 5.0 keV noise. Cathode signal is used to do both the rejection and the correction in the SEFLA prototype. At the cost of detection efficiency, the low energy tail is reduced, while the energy resolution and the P/C ratio are further improved. Possible improvements of the detectors are discussed.

  14. Prone Hypofractionated Whole-Breast Radiotherapy Without a Boost to the Tumor Bed: Comparable Toxicity of IMRT Versus a 3D Conformal Technique

    SciTech Connect

    Hardee, Matthew E.; Raza, Shahzad; Becker, Stewart J.; Jozsef, Gabor; Lymberis, Stella C.; Hochman, Tsivia; Goldberg, Judith D.; DeWyngaert, Keith J.; Formenti, Silvia C.

    2012-03-01

    confirmed benefit in terms of toxicities. If a concurrent boost to the tumor bed is not required, a conformal 3D-CRT approach can adequately deliver prone whole-breast hypofractionation radiotherapy.

  15. Tracking down hyper-boosted top quarks

    DOE PAGESBeta

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directlymore » employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.« less

  16. Tracking down hyper-boosted top quarks

    SciTech Connect

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  17. Calculations of transient fields in the Felix experiments at Argonne using null field integrated techniques

    NASA Astrophysics Data System (ADS)

    Han, H. C.; Davey, K. R.; Turner, L.

    1985-08-01

    The transient eddy current problem is characteristically computationally intensive. The motivation for this research was to realize an efficient, accurate, solution technique involving small matrices via an eigenvalue approach. Such a technique is indeed realized and tested using the null field integral technique. Using smart (i.e., efficient, global) basis functions to represent unknowns in terms of a minimum number of unknowns, homogeneous eigenvectors and eigenvalues are first determined. The general excitatory response is then represented in terms of these eigenvalues/eigenvectors. Excellent results are obtained for the Argonne Felix cylinder experiments using a 4 x 4 matrix. Extension to the 3-D problem (short cylinder) is set up in terms of an 8 x 8 matrix.

  18. Determination of the far-field from measured near-field data, theory and measuring technique of the near-field far-field transformation

    NASA Astrophysics Data System (ADS)

    Schrott, A.; Stein, V.

    1980-12-01

    Methods are described for measuring the far field of antennas at distances that are small compared to the wavelength of the field. The so called compact test range is explained and the principle of the near field far field transformation is described. The advantages and disadvantages of the planar, cylindrical, and spherical transformation techniques are discussed. Theory and measuring technique for the spherical method are treated extensively. An assessment of the influence of errors is given and the acceptable tolerances are presented. A proposal is given for the construction of a near field test range. Finally the performance of the method is demonstrated with the aid of some examples.

  19. Evaluation of the field-in-field technique with lung blocks for breast tangential radiotherapy.

    PubMed

    Tanaka, Hidekazu; Hayashi, Shinya; Kajiura, Yuichi; Kitahara, Masashi; Matsuyama, Katsuya; Kanematsu, Masayuki; Hoshi, Hiroaki

    2015-08-01

    Several studies have reported the advantages of the field-in-field (FIF) technique in breast radiotherapy, including dose reduction in the lungs by using lung field blocks. We evaluated the FIF technique with lung blocks for breast tangential radiotherapy. Sixteen patients underwent free breathing (FB) computed tomography (CT), followed by two CT procedures performed during breath hold after light inhalation (IN) and light exhalation (EX). Three radiotherapy plans were created using the FIF technique based on the FB-CT images: one without lung blocks (LB0) and two with lung blocks whose monitor units (MUs) were 5 (LB5) and 10 (LB10), respectively. These plans were copied to the IN-CT and EX-CT images. V20Gy, V30Gy, and V40Gy of the ipsilateral lung and V100%, V95%, and the mean dose (Dmean) to the planning target volume (PTV) were analyzed. The extent of changes in these parameters on the IN-plan and EX-plan compared with the FB-plan was evaluated. V20Gy, V30Gy, and V40Gy were significantly smaller for FB-LB5 and FB-LB10 than for FB-LB0; similar results were obtained for the IN-plan and EX-plan. V100%, V95%, and Dmean were also significant smaller for FB-LB5 and FB-LB10 than for FB-LB0. The extent of changes in V20Gy, V30Gy, and V40Gy on the IN-plan and EX-plan compared with the FB-plan was not statistically significant. Lung blocks were useful for dose reduction in the lung and a simultaneous PTV decrease. This technique should not be applied in the general population. PMID:26412879

  20. Evaluation of the field-in-field technique with lung blocks for breast tangential radiotherapy

    PubMed Central

    Tanaka, Hidekazu; Hayashi, Shinya; Kajiura, Yuichi; Kitahara, Masashi; Matsuyama, Katsuya; Kanematsu, Masayuki; Hoshi, Hiroaki

    2015-01-01

    ABSTRACT Several studies have reported the advantages of the field-in-field (FIF) technique in breast radiotherapy, including dose reduction in the lungs by using lung field blocks. We evaluated the FIF technique with lung blocks for breast tangential radiotherapy. Sixteen patients underwent free breathing (FB) computed tomography (CT), followed by two CT procedures performed during breath hold after light inhalation (IN) and light exhalation (EX). Three radiotherapy plans were created using the FIF technique based on the FB-CT images: one without lung blocks (LB0) and two with lung blocks whose monitor units (MUs) were 5 (LB5) and 10 (LB10), respectively. These plans were copied to the IN-CT and EX-CT images. V20Gy, V30Gy, and V40Gy of the ipsilateral lung and V100%, V95%, and the mean dose (Dmean) to the planning target volume (PTV) were analyzed. The extent of changes in these parameters on the IN-plan and EX-plan compared with the FB-plan was evaluated. V20Gy, V30Gy, and V40Gy were significantly smaller for FB-LB5 and FB-LB10 than for FB-LB0; similar results were obtained for the IN-plan and EX-plan. V100%, V95%, and Dmean were also significant smaller for FB-LB5 and FB-LB10 than for FB-LB0. The extent of changes in V20Gy, V30Gy, and V40Gy on the IN-plan and EX-plan compared with the FB-plan was not statistically significant. Lung blocks were useful for dose reduction in the lung and a simultaneous PTV decrease. This technique should not be applied in the general population. PMID:26412879

  1. Mean field spin glasses treated with PDE techniques

    NASA Astrophysics Data System (ADS)

    Barra, Adriano; Del Ferraro, Gino; Tantari, Daniele

    2013-07-01

    Following an original idea of Guerra, in these notes we analyze the Sherrington-Kirkpatrick model from different perspectives, all sharing the underlying approach which consists in linking the resolution of the statistical mechanics of the model (e.g. solving for the free energy) to well-known partial differential equation (PDE) problems (in suitable spaces). The plan is then to solve the related PDE using techniques involved in their native field and lastly bringing back the solution in the proper statistical mechanics framework. Within this strand, after a streamlined test-case on the Curie-Weiss model to highlight the methods more than the physics behind, we solve the SK both at the replica symmetric and at the 1-RSB level, obtaining the correct expression for the free energy via an analogy to a Fourier equation and for the self-consistencies with an analogy to a Burger equation, whose shock wave develops exactly at critical noise level (triggering the phase transition). Our approach, beyond acting as a new alternative method (with respect to the standard routes) for tackling the complexity of spin glasses, links symmetries in PDE theory with constraints in statistical mechanics and, as a novel result from the theoretical physics perspective, we obtain a new class of polynomial identities (namely of Aizenman-Contucci type, but merged within the Guerra's broken replica measures), whose interest lies in understanding, via the recent Panchenko breakthroughs, how to force the overlap organization to the ultrametric tree predicted by Parisi.

  2. The virtual microphone technique in active sound field control systems

    NASA Astrophysics Data System (ADS)

    Lampropoulos, Iraklis E.; Shimizu, Yasushi

    2003-04-01

    Active Sound Field Control (AFC) has been proven very useful in reverberation enhancement applications in large rooms. However, feedback control is required in order to eliminate peaks in the frequency response of the system. The present research closely follows the studies of Shimizu in AFC, in which smoothing of the rooms transfer function is achieved by averaging the impulse responses of multiple microphones. ``The virtual or rotating microphone technique'' reduces the number of microphones in the aforementioned AFC technology, while still achieving the same acoustical effects in the room. After the impulse responses at previously specified pairs of microphone positions are measured, the ratio of transfer functions for every pair is calculated, thus yielding a constant K. Next, microphones are removed and their impulse responses are reproduced by processing the incoming signal of each pair through a convolver, where the computed K constants have been previously stored. Band limiting, windowing and time variance effects are critical factors, in order to reduce incoherence effects and yield reliable approximations of inverse filters and consequently calculations of K. The project is implemented in a church lacking low frequency reverberation for music and makes use of 2 physical and 2 virtual microphones.

  3. A technique for automatically extracting useful field of view and central field of view images

    PubMed Central

    Pandey, Anil Kumar; Sharma, Param Dev; Aheer, Deepak; Kumar, Jay Prakash; Sharma, Sanjay Kumar; Patel, Chetan; Kumar, Rakesh; Bal, Chandra Sekhar

    2016-01-01

    Introduction: It is essential to ensure the uniform response of the single photon emission computed tomography gamma camera system before using it for the clinical studies by exposing it to uniform flood source. Vendor specific acquisition and processing protocol provide for studying flood source images along with the quantitative uniformity parameters such as integral and differential uniformity. However, a significant difficulty is that the time required to acquire a flood source image varies from 10 to 35 min depending both on the activity of Cobalt-57 flood source and the pre specified counts in the vendors protocol (usually 4000K-10,000K counts). In case the acquired total counts are less than the total prespecified counts, and then the vendor's uniformity processing protocol does not precede with the computation of the quantitative uniformity parameters. In this study, we have developed and verified a technique for reading the flood source image, remove unwanted information, and automatically extract and save the useful field of view and central field of view images for the calculation of the uniformity parameters. Materials and Methods: This was implemented using MATLAB R2013b running on Ubuntu Operating system and was verified by subjecting it to the simulated and real flood sources images. Results: The accuracy of the technique was found to be encouraging, especially in view of practical difficulties with vendor-specific protocols. Conclusion: It may be used as a preprocessing step while calculating uniformity parameters of the gamma camera in lesser time with fewer constraints. PMID:27095858

  4. Field results of antifouling techniques for optical instruments

    USGS Publications Warehouse

    Strahle, W.J.; Hotchkiss, F.S.; Martini, M.A.

    1998-01-01

    An anti-fouling technique is developed for the protection of optical instruments from biofouling which leaches a bromide compound into a sample chamber and pumps new water into the chamber prior to measurement. The primary advantage of using bromide is that it is less toxic than the metal-based antifoulants. The drawback of the bromide technique is also discussed.

  5. Remote field eddy current technique - Phantom exciter model calculations

    NASA Astrophysics Data System (ADS)

    Atherton, D. L.; Czura, W.

    1993-03-01

    High resolution results of finite element calculations for remote field eddy current 'phantom exciter' simulations of slit defect interactions using single through wall transit are presented. These show that fine circumferential slits cause almost no field perturbations in the case of nonferromagnetic tubes but big perturbations in ferromagnetic tubes where high magnetic H fields occur in the slits. Defect-induced magnetic field perturbations must therefore be considered in addition to eddy current perturbations when ferromagnetic materials are inspected, particularly in the case of fine slits orthogonal to the magnetic field direction. Additional details seen are the funnelling of energy into slits in ferromagnetic pipes and precursor disturbances of fields approaching defects. It is suggested that these are due to the reflection of the electromagnetic waves dictated by boundary conditions at the near-side defect boundary.

  6. Boosting classification performance in computer aided diagnosis of breast masses in raw full-field digital mammography using processed and screen film images

    NASA Astrophysics Data System (ADS)

    Kooi, Thijs; Karssemeijer, Nico

    2014-03-01

    The introduction of Full-Field Digital Mammography (FFDM) in breast screening has brought with it several advantages in terms and processing facilities and image quality and Computer Aided Detection (CAD) systems are now sprouting that make use of this modality. A major drawback however, is that FFDM data is still relatively scarce and therefore, CAD system's performance are inhibited by a lack of training examples. In this paper, we explore the incorporation of more ubiquitous Screen Film Mammograms (SFM) and FFDM processed by the manufacturer, in training a system for the detection of tumour masses. We compute a small set of additional quantitative features in the raw data, that make explicit use of the log-linearity of the energy imparted on the detector in raw FFDM. We explore four di erent fusion methods: a weighted average, a majority vote, a convex combination of classi er outputs, based on the training error and an additional classi er, that combines the output of the three individual label estimates. Results are evaluated based on the Partial Area Under the Curve (PAUC) around a clinically relevant operating point. All fusion methods perform signi cantly better than any of the individual classi ers but we nd no signi cant di erence between the fusion techniques.

  7. Boson mapping techniques applied to constant gauge fields in QCD

    NASA Technical Reports Server (NTRS)

    Hess, Peter Otto; Lopez, J. C.

    1995-01-01

    Pairs of coordinates and derivatives of the constant gluon modes are mapped to new gluon-pair fields and their derivatives. Applying this mapping to the Hamiltonian of constant gluon fields results for large coupling constants into an effective Hamiltonian which separates into one describing a scalar field and another one for a field with spin two. The ground state is dominated by pairs of gluons coupled to color and spin zero with slight admixtures of color zero and spin two pairs. As color group we used SU(2).

  8. Technique for Predicting the Radio Frequency Field Strength Inside an Enclosure

    NASA Technical Reports Server (NTRS)

    Hallett, Michael P.; Reddell, Jerry P.

    1997-01-01

    This technical memo represents a simple analytical technique for predicting the Radio Frequency (RF) field inside an enclosed volume in which radio frequency occurs. The technique was developed to predict the RF field strength within a launch vehicle fairing in which some payloads desire to launch with their telemetry transmitter radiating. This technique considers both the launch vehicle and the payload aspects.

  9. Highly sensitive tITP-CZE determination of l-histidine and creatinine in human blood plasma using field-amplified sample injection with mobility-boost effect.

    PubMed

    Hattori, Takanari; Fukushi, Keiichi

    2016-01-01

    2D computer simulation revealed that amino acids and weak electrolytes were cationized because of the migration of counter-ion from a BGE zone to a sample zone, which encouraged electrokinetic injection (EKI) of these analytes (by the mobility-boost (MB) effect). To investigate the effects of kinds and concentrations of counter-ions on the MB effect and the analyte amount injected into the capillary, experiments, and 1D computer simulations were performed. When acetate was used as the counter-ion, the LODs (S/N = 3) of l-histidine and creatinine, respectively, reached 0.10 and 0.25 nM because of the concentration effect by transient ITP (tITP). The concentrations of l-histidine and creatinine in human blood plasma obtained using the proposed method were agreed with those obtained using the conventional methods. The proposed method can be applied to the analysis of amino acids and weak bases that have similar pI and pKa to l-histidine and creatinine. PMID:26454141

  10. Analytic boosted boson discrimination

    NASA Astrophysics Data System (ADS)

    Larkoski, Andrew J.; Moult, Ian; Neill, Duff

    2016-05-01

    Observables which discriminate boosted topologies from massive QCD jets are of great importance for the success of the jet substructure program at the Large Hadron Collider. Such observables, while both widely and successfully used, have been studied almost exclusively with Monte Carlo simulations. In this paper we present the first all-orders factorization theorem for a two-prong discriminant based on a jet shape variable, D 2, valid for both signal and background jets. Our factorization theorem simultaneously describes the production of both collinear and soft subjets, and we introduce a novel zero-bin procedure to correctly describe the transition region between these limits. By proving an all orders factorization theorem, we enable a systematically improvable description, and allow for precision comparisons between data, Monte Carlo, and first principles QCD calculations for jet substructure observables. Using our factorization theorem, we present numerical results for the discrimination of a boosted Z boson from massive QCD background jets. We compare our results with Monte Carlo predictions which allows for a detailed understanding of the extent to which these generators accurately describe the formation of two-prong QCD jets, and informs their usage in substructure analyses. Our calculation also provides considerable insight into the discrimination power and calculability of jet substructure observables in general.

  11. Advanced measurements and techniques in high magnetic fields

    SciTech Connect

    Campbell, L.J.; Rickel, D.G.; Lacerda, A.H.; Kim, Y.

    1997-07-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). High magnetic fields present a unique environment for studying the electronic structure of materials. Two classes of materials were chosen for experiments at the national high Magnetic Field Laboratory at Los Alamos: highly correlated electron systems and semiconductors. Magnetotransport and thermodynamic experiments were performed on the renormalized ground states of highly correlated electron systems (such as heavy fermion materials and Kondo insulators) in the presence of magnetic fields that are large enough to disrupt the many-body correlations. A variety of optical measurements in high magnetic fields were performed on semiconductor heterostructures including GaAs/AlGaAs single heterojunctions (HEMT structure), coupled double quantum wells (CDQW), asymmetric coupled double quantum wells (ACDQW), multiple quantum wells and a CdTe single crystal thin film.

  12. Experimental Validation of Simulations Using Full-field Measurement Techniques

    SciTech Connect

    Hack, Erwin

    2010-05-28

    The calibration by reference materials of dynamic full-field measurement systems is discussed together with their use to validate numerical simulations of structural mechanics. The discussion addresses three challenges that are faced in these processes, i.e. how to calibrate a measuring instrument that (i) provides full-field data, and (ii) is dynamic; (iii) how to compare data from simulation and experimentation.

  13. Voltage-Boosting Driver For Switching Regulator

    NASA Technical Reports Server (NTRS)

    Trump, Ronald C.

    1990-01-01

    Driver circuit assures availability of 10- to 15-V gate-to-source voltage needed to turn on n-channel metal oxide/semiconductor field-effect transistor (MOSFET) acting as switch in switching voltage regulator. Includes voltage-boosting circuit efficiently providing gate voltage 10 to 15 V above supply voltage. Contains no exotic parts and does not require additional power supply. Consists of NAND gate and dual voltage booster operating in conjunction with pulse-width modulator part of regulator.

  14. COMPARING FIELD PERFORMANCES OF DENUDER TECHNIQUES IN THE HIGH ARCTIC

    EPA Science Inventory

    A field evaluation between two annular denuder system configurations was conducted during the spring of 2003 in the marine Arctic (Ny-Ålesund, Svalbard). The IIA annular denuder system (ADS) employs a series of five single channel annular denuders, a cyclone and a filter pack to ...

  15. The Development of Teaching and Learning in Bright-Field Microscopy Technique

    ERIC Educational Resources Information Center

    Iskandar, Yulita Hanum P.; Mahmud, Nurul Ethika; Wahab, Wan Nor Amilah Wan Abdul; Jamil, Noor Izani Noor; Basir, Nurlida

    2013-01-01

    E-learning should be pedagogically-driven rather than technologically-driven. The objectives of this study are to develop an interactive learning system in bright-field microscopy technique in order to support students' achievement of their intended learning outcomes. An interactive learning system on bright-field microscopy technique was…

  16. Field inter-comparison of eleven atmospheric ammonia measurement techniques

    NASA Astrophysics Data System (ADS)

    von Bobrutzki, K.; Braban, C. F.; Famulari, D.; Jones, S. K.; Blackall, T.; Smith, T. E. L.; Blom, M.; Coe, H.; Gallagher, M.; Ghalaieny, M.; McGillen, M. R.; Percival, C. J.; Whitehead, J. D.; Ellis, R.; Murphy, J.; Mohacsi, A.; Pogany, A.; Junninen, H.; Rantanen, S.; Sutton, M. A.; Nemitz, E.

    2010-01-01

    Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in Southern Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD) and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia), two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system; DUAL-QCLAS, and a compact system; c-QCLAS), two photo-acoustic spectrometers (WaSul-Flux; Nitrolux-100), a Cavity Ring Down Spectrosmeter (CRDS), a Chemical Ionisation Mass Spectrometer (CIMS), an ion mobility spectrometer (IMS) and an Open-Path Fourier Transform Infra-Red (OP-FTIR) Spectrometer. The instruments were compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2>0.84), was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS) to 1.13 (AiRRmonia) with intercepts of -0.74 ppbv (RBD) to +2.69 ppbv (CIMS). More variability was found for performance for lower concentrations (<10 ppbv). Here the main factors affecting measurement precision are (a) the inlet design, (b) the state of inlet filters (where applicable), and (c) the quality of gas-phase standards (where applicable). By reference to the fast (1 Hz) instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

  17. Field inter-comparison of eleven atmospheric ammonia measurement techniques

    NASA Astrophysics Data System (ADS)

    von Bobrutzki, K.; Braban, C. F.; Famulari, D.; Jones, S. K.; Blackall, T.; Smith, T. E. L.; Blom, M.; Coe, H.; Gallagher, M.; Ghalaieny, M.; McGillen, M. R.; Percival, C. J.; Whitehead, J. D.; Ellis, R.; Murphy, J.; Mohacsi, A.; Junninen, H.; Pogany, A.; Rantanen, S.; Sutton, M. A.; Nemitz, E.

    2009-08-01

    Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH3), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in S. Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading to an increase in the average concentration from 10 to 100 ppbv. The instruments deployed included three wet-chemistry systems, one with offline analysis (annular rotating batch denuder, RBD) and two with online-analysis (Annular Denuder sampling with online Analysis, AMANDA; AiRRmonia), two Quantum Cascade Laser Absorption Spectrometers (a large-cell dual system, DUAL-QCLAS, and a compact system, c-QCLAS), two photo-acoustic spectrometers (WaSul-Flux, Nitrolux-100), a Cavity Ring Down Spectrosmeter (CRDS), a Chemical Ionisation Mass Spectrometer (CIMS), an ion mobility spectrometer (IMS) and an Open-Path Fourier Transform Infra-Red (OP-FTIR) spectroscopy. Each instrument was compared with each other and with the average concentration of all instruments. An overall good agreement of hourly average concentrations between the instruments (R2>0.84), was observed for NH3 concentrations at the field of up to 120 ppbv with the slopes against the average ranging from 0.67 (DUAL-QCLAS) to 1.13 (AiRRmonia) with intercepts of -0.74 ppbv (RBD) to +2.69 ppbv (CIMS). More variability was found for performance for lower concentrations (<10 ppbv). Here the overruling factors affecting measurement precision are (a) the inlet design, (b) the state of inlet filters (where applicable), and (c) the quality of gas-phase standards (where applicable). By reference to the fast (1 Hz) instruments deployed during the study, it was possible to characterize the response times of the slower instruments.

  18. Work function measurements using a field emission retarding potential technique.

    PubMed

    Hamanaka, M H M O; Dall'Agnol, F F; Pimentel, V L; Mammana, V P; Tatsch, P J; den Engelsen, D

    2016-03-01

    Herein we describe the measurement of the work function of a metal with advanced equipment based on the field emission retarding potential (FERP) method using a carbon nanotube (CNT) as cathode. The accuracy of the FERP method using a CNT emitter is described and a comparison between measurements of the work functions of aluminum, barium, calcium, gold, and platinum with published data will be presented. Our FERP equipment could be optimized with the aid of particle tracing simulations. These simulations led us to insert a magnetic collimator to improve the collection efficiency at the anode. PMID:27036828

  19. Work function measurements using a field emission retarding potential technique

    NASA Astrophysics Data System (ADS)

    Hamanaka, M. H. M. O.; Dall'Agnol, F. F.; Pimentel, V. L.; Mammana, V. P.; Tatsch, P. J.; den Engelsen, D.

    2016-03-01

    Herein we describe the measurement of the work function of a metal with advanced equipment based on the field emission retarding potential (FERP) method using a carbon nanotube (CNT) as cathode. The accuracy of the FERP method using a CNT emitter is described and a comparison between measurements of the work functions of aluminum, barium, calcium, gold, and platinum with published data will be presented. Our FERP equipment could be optimized with the aid of particle tracing simulations. These simulations led us to insert a magnetic collimator to improve the collection efficiency at the anode.

  20. Extended Field Intensity Modulated Radiation Therapy With Concomitant Boost for Lymph Node–Positive Cervical Cancer: Analysis of Regional Control and Recurrence Patterns in the Positron Emission Tomography/Computed Tomography Era

    SciTech Connect

    Vargo, John A.; Kim, Hayeon; Choi, Serah; Sukumvanich, Paniti; Olawaiye, Alexander B.; Kelley, Joseph L.; Edwards, Robert P.; Comerci, John T.; Beriwal, Sushil

    2014-12-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is commonly used for nodal staging in locally advanced cervical cancer; however the false negative rate for para-aortic disease are 20% to 25% in PET-positive pelvic nodal disease. Unless surgically staged, pelvis-only treatment may undertreat para-aortic disease. We have treated patients with PET-positive nodes with extended field intensity modulated radiation therapy (IMRT) to address the para-aortic region prophylactically with concomitant boost to involved nodes. The purpose of this study was to assess regional control rates and recurrence patterns. Methods and Materials: Sixty-one patients with cervical cancer (stage IBI-IVA) diagnosed from 2003 to 2012 with PET-avid pelvic nodes treated with extended field IMRT (45 Gy in 25 fractions with concomitant boost to involved nodes to a median of 55 Gy in 25 fractions) with concurrent cisplatin and brachytherapy were retrospectively analyzed. The nodal location was pelvis-only in 41 patients (67%) and pelvis + para-aortic in 20 patients (33%). There were a total of 179 nodes, with a median number of positive nodes of 2 (range, 1-16 nodes) per patient and a median nodal size of 1.8 cm (range, 0.7-4.5 cm). Response was assessed by PET/CT at 12 to 16 weeks. Results: Complete clinical and imaging response at the first follow-up visit was seen in 77% of patients. At a mean follow-up time of 29 months (range, 3-116 months), 8 patients experienced recurrence. The sites of persistent/recurrent disease were as follows: cervix 10 (16.3%), regional nodes 3 (4.9%), and distant 14 (23%). The rate of para-aortic failure in patients with pelvic-only nodes was 2.5%. There were no significant differences in recurrence patterns by the number/location of nodes, largest node size, or maximum node standardized uptake value. The rate of late grade 3+ adverse events was 4%. Conclusions: Extended field IMRT was well tolerated and resulted in low regional recurrence

  1. Geomagnetic Field Effects on the Imaging Air Shower Cherenkov Technique

    NASA Astrophysics Data System (ADS)

    Commichau, S.C.; Biland, A.; Kranich, D.; de los Reyes, R.; Moralejo, A.; Sobczyńska, D.

    Imaging Air Cherenkov Telescopes (IACTs) detect the Cherenkov light flashes of Extended Air Showers (EAS) triggered by VHE gamma-rays impinging on the Earth's atmosphere. Due to the overwhelming background from hadron induced EAS, the discrimination of the rare gamma-like events is rather difficult, in particular at energies below 100 GeV. The influence of the Geomagnetic Field (GF) on the EAS development can further complicate this discrimination and, in addition, also systematically affect the gamma-efficiency and energy resolution of an IACT. Here we present the results from dedicated Monte Carlo (MC) simulations for the MAGIC telescope site, show the GF effects on real data as well as possible corrections for these effects.

  2. Near-field imaging techniques for surface inspection

    NASA Astrophysics Data System (ADS)

    Dannenberg, Florian; Hahlweg, Cornelius; Pescoller, Lukas; Zhao, Wenjing

    2014-09-01

    Following the recent work on the characterization of flexo-printing plates a concept for inspection of glossy surfaces using a defined out of focus image of the surface under parallel illumination is presented, which in principle represents a near field distribution of the reflection function of the surface. The image turns out to be equivalent to a focussed shadowgraph as used for the investigation of processes in transparent media. Beside the plain 'reflected shadow imaging' several degrees of freedom can be exploited for configuration of the feature emphasis. The method is especially interesting for the quality control of printed matter. In the paper the definition of the system, the mechanism of the imaging process and its relation to the real image of the surface itself are considered. Further, questions of resolution, extractable features and extended applications are discussed.

  3. Fostered Thermomagnetic Stabilities and Boosted Mechanical Reliability Related to High Trapped Field in Composite Bulk YBa2Cu3O(7-δ) Cryomagnets.

    PubMed

    Kenfaui, Driss; Sibeud, Pierre-Frédéric; Gomina, Moussa; Louradour, Eric; Chaud, Xavier; Noudem, Jacques G

    2015-08-01

    In the quest of YBa2Cu3O(7-δ) (Y123) bulk superconductors providing strong magnetic fields without failure, it is of paramount importance to achieve high thermal stabilities to safeguard the magnetic energy inside them during the trapping-field process, and sufficient mechanical reliability to withstand the stresses derived from the Lorenz force. Herein, we experimentally demonstrate a temperature rise induced by dissipative flux motion inside an Y123 thin-wall superconductor, and a significant thermal exchange in a composite bulk Y123 cryomagnet realized by embedding this superconductor with high thermal-conductivity metal network. It resulted in stimulating the maximum trapped field Bm, which reached 6.46 T on 15.9 mm-diameter single disk superconductor after magnetization by field cooling to 17 K under 7 T, leading to an improvement of 18% compared to the thin-wall superconductor. The composite cryomagnet particularly revealed the potential to trap stronger fields if larger magnetic activation is available. By virtue of the pore-free and crack-free microstructure of this cryomagnet, its strength σR was estimated to be 363 MPa, the largest one obtained so far for Y123 bulk superconductors, thus suggesting a striking mechanical reliability that seems to be sufficient to sustain stresses derived from trapped fields stronger than any values hitherto reported. PMID:26267194

  4. AveBoost2: Boosting for Noisy Data

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.

    2004-01-01

    AdaBoost is a well-known ensemble learning algorithm that constructs its constituent or base models in sequence. A key step in AdaBoost is constructing a distribution over the training examples to create each base model. This distribution, represented as a vector, is constructed to be orthogonal to the vector of mistakes made by the pre- vious base model in the sequence. The idea is to make the next base model's errors uncorrelated with those of the previous model. In previous work, we developed an algorithm, AveBoost, that constructed distributions orthogonal to the mistake vectors of all the previous models, and then averaged them to create the next base model s distribution. Our experiments demonstrated the superior accuracy of our approach. In this paper, we slightly revise our algorithm to allow us to obtain non-trivial theoretical results: bounds on the training error and generalization error (difference between training and test error). Our averaging process has a regularizing effect which, as expected, leads us to a worse training error bound for our algorithm than for AdaBoost but a superior generalization error bound. For this paper, we experimented with the data that we used in both as originally supplied and with added label noise-a small fraction of the data has its original label changed. Noisy data are notoriously difficult for AdaBoost to learn. Our algorithm's performance improvement over AdaBoost is even greater on the noisy data than the original data.

  5. Bidirectional buck boost converter

    DOEpatents

    Esser, Albert Andreas Maria

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  6. Bidirectional buck boost converter

    DOEpatents

    Esser, A.A.M.

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

  7. Boosting with Averaged Weight Vectors

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    AdaBoost is a well-known ensemble learning algorithm that constructs its constituent or base models in sequence. A key step in AdaBoost is constructing a distribution over the training examples to create each base model. This distribution, represented as a vector, is constructed to be orthogonal to the vector of mistakes made by the previous base model in the sequence. The idea is to make the next base model's errors uncorrelated with those of the previous model. Some researchers have pointed out the intuition that it is probably better to construct a distribution that is orthogonal to the mistake vectors of all the previous base models, but that this is not always possible. We present an algorithm that attempts to come as close as possible to this goal in an efficient manner. We present experimental results demonstrating significant improvement over AdaBoost and the Totally Corrective boosting algorithm, which also attempts to satisfy this goal.

  8. Image enhancement based on edge boosting algorithm

    NASA Astrophysics Data System (ADS)

    Ngernplubpla, Jaturon; Chitsobhuk, Orachat

    2015-12-01

    In this paper, a technique for image enhancement based on proposed edge boosting algorithm to reconstruct high quality image from a single low resolution image is described. The difficulty in single-image super-resolution is that the generic image priors resided in the low resolution input image may not be sufficient to generate the effective solutions. In order to achieve a success in super-resolution reconstruction, efficient prior knowledge should be estimated. The statistics of gradient priors in terms of priority map based on separable gradient estimation, maximum likelihood edge estimation, and local variance are introduced. The proposed edge boosting algorithm takes advantages of these gradient statistics to select the appropriate enhancement weights. The larger weights are applied to the higher frequency details while the low frequency details are smoothed. From the experimental results, the significant performance improvement quantitatively and perceptually is illustrated. It can be seen that the proposed edge boosting algorithm demonstrates high quality results with fewer artifacts, sharper edges, superior texture areas, and finer detail with low noise.

  9. [Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

    PubMed

    Jiang, Zhi-quan; Hu, Ke-liang

    2016-03-01

    In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science. PMID:27400510

  10. Review of neutron calibration facilities and monitoring techniques: new needs for emerging fields.

    PubMed

    Gressier, V

    2014-10-01

    Neutron calibration facilities and monitoring techniques have been developed since the middle of the 20th century to support research and nuclear power energy development. The technical areas needing reference neutron fields and related instruments were mainly cross section measurements, radiation protection, dosimetry and fission reactors, with energy ranging from a few millielectronvolts to about 20 MeV. The reference neutron fields and calibration techniques developed for these purposes will be presented in this paper. However, in recent years, emerging fields have brought new needs for calibration facilities and monitoring techniques. These new challenges for neutron metrology will be exposed with their technical difficulties. PMID:24344349

  11. A Magnetohydrodynamic Boost for Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Mizuno, Yosuke; Hardee, Philip; Hartmann, Dieter H.; Nishikawa, Ken-Ichi; Zhang, Bing

    2007-01-01

    We performed relativistic magnetohydrodynamic simulations of the hydrodynamic boosting mechanism for relativistic jets explored by Aloy & Rezzolla (2006) using the RAISHIN code. Simulation results show that the presence of a magnetic field changes the properties of the shock interface between the tenuous, overpressured jet (V^z j) flowing tangentially to a dense external medium. We find that magnetic fields can lead to more efficient acceleration of the jet, in comparison to the pure-hydrodynamic case. A "poloidal" magnetic field (B^z), tangent to the interface and parallel to the jet flow, produces both a stronger outward moving shock and a stronger inward moving rarefaction wave. This leads to a large velocity component normal to the interface in addition to acceleration tangent to the interface, and the jet is thus accelerated to larger Lorentz factors than those obtained in the pure-hydrodynamic case. Likewise, a strong "toroidal" magnetic field (B^y), tangent to the interface but perpendicular to the jet flow, also leads to stronger acceleration tangent to the shock interface relative to the pure-hydrodynamic case. Thus. the presence and relative orientation of a magnetic field in relativistic jets can significant modify the hydrodynamic boost mechanism studied by Aloy & Rezzolla (2006).

  12. Electroacoustical imaging technique for encoding incoherent radiance fields as Gabor elementary signals

    NASA Technical Reports Server (NTRS)

    Fales, C. L.; Huck, F. O.

    1985-01-01

    A technique is presented for directly encoding incoherent radiance fields as Gabor elementary signals. This technique uses an electro-acoustic sensor to modulate the electronic charges induced by the incident radiance field with the electric fields generated by Gaussian modulated sinusoidal acoustic waves. The resultant signal carries the amplitude and phase information required for localizing spatial frequencies of the radiance field. These localized spatial frequency representations provide a link between the either geometric or Fourier transform representations currently used in computer vision and pattern recognition.

  13. Field-aligned electric currents and their measurement by the incoherent backscatter technique

    NASA Technical Reports Server (NTRS)

    Bauer, P.; Cole, K. D.; Lejeume, G.

    1975-01-01

    Field aligned electric currents flow in the magnetosphere in many situations of fundamental geophysical interest. It is shown here that the incoherent backscatter technique can be used to measure these currents when the plasma line can be observed. The technique provides a ground based means of measuring these currents which complements the rocket and satellite ones.

  14. Epidemiological studies on onchocerciasis by means of a new field technique*

    PubMed Central

    Scheiber, P.; Braun-Munzinger, R. A.; Southgate, B. A.; Agbo, K. N.

    1976-01-01

    A new membrane filter concentration technique for the detection and quantification of Onchocerca volvulus microfilariae in skin snips was compared for sensitivity and efficiency with a widely used “standard” technique. A field study was carried out in five villages in an onchocerciasis focus north-east of the town of Sokodé, Mô river valley, Togo. Use of the new technique resulted in a substantial rise in the observed prevalence and density of microfilariae. PMID:1086740

  15. Philippine campaign boosts child immunizations.

    PubMed

    Manuel-santana, R

    1993-03-01

    In 1989, USAID awarded the Philippines a 5-year, US $50 million Child Survival Program targeting improvement in immunization coverage of children, prenatal care coverage for pregnant women, and contraceptive prevalence. Upon successful completion of performance benchmarks at the end of each year, USAID released monies to fund child survival activities for the following year. This program accomplished a major program goal, which was decentralization of health planning. The Philippine Department of Health soon incorporated provincial health planning. The Philippine Department of Health soon incorporated provincial health planning in its determination of allocation of resources. Social marketing activities contributed greatly to success in achieving the goal of boosting the immunization coverage rate for the 6 antigens listed under the Expanded Program for Immunization (51%-85% of infants, 1986-1991). In fact, rural health officers in Tarlac Province in Central Luzon went from household to household to talk to mothers about the benefits of immunizing a 1-year-old child, thereby contributing greatly to their achieving a 95% full immunization coverage rate by December 1991. Social marketing techniques included modern marketing strategies and multimedia channels. They first proved successful in metro Manila which, at the beginning of the campaign, had the lowest immunization rate of all 14 regions. Every Wednesday was designated immunization day and was when rural health centers vaccinated the children. Social marketing also successfully publicized oral rehydration therapy (ORT), breast feeding, and tuberculosis control. Another contributing factor to program success in child survival activities was private sector involvement. For example, the Philippine Pediatric Society helped to promote ORT as the preferred treatment for acute diarrhea. Further, the commercial sector distributed packets of oral rehydration salts and even advertised its own ORT product. At the end of 2

  16. Boost matrix converters in clean energy systems

    NASA Astrophysics Data System (ADS)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  17. Accessing Interior Vector Magnetic Field Components in Neutron EDM Experiments via Boundary Value Techniques

    NASA Astrophysics Data System (ADS)

    Plaster, Brad

    2012-10-01

    We propose a new technique for the determination and monitoring of the interior vector magnetic field components during the operation of neutron EDM experiments. If a suitable three-dimensional volume surrounding the fiducial volume of an experiment can be defined which contains no interior currents or magnetization, each of the interior vector field components will satisfy the Laplace Equation within this volume. Therefore, if the field components can be measured on the boundary, the interior vector field components can be determined uniquely via numerical solution of the Laplace Equation. We discuss the applicability of this technique to the determination of the magnetic field components and magnetic field gradients in the fiducial volumes of neutron EDM experiments.

  18. Boosted Jets at the LHC

    NASA Astrophysics Data System (ADS)

    Larkoski, Andrew

    2015-04-01

    Jets are collimated streams of high-energy particles ubiquitous at any particle collider experiment and serve as proxy for the production of elementary particles at short distances. As the Large Hadron Collider at CERN continues to extend its reach to ever higher energies and luminosities, an increasingly important aspect of any particle physics analysis is the study and identification of jets, electroweak bosons, and top quarks with large Lorentz boosts. In addition to providing a unique insight into potential new physics at the tera-electron volt energy scale, high energy jets are a sensitive probe of emergent phenomena within the Standard Model of particle physics and can teach us an enormous amount about quantum chromodynamics itself. Jet physics is also invaluable for lower-level experimental issues including triggering and background reduction. It is especially important for the removal of pile-up, which is radiation produced by secondary proton collisions that contaminates every hard proton collision event in the ATLAS and CMS experiments at the Large Hadron Collider. In this talk, I will review the myriad ways that jets and jet physics are being exploited at the Large Hadron Collider. This will include a historical discussion of jet algorithms and the requirements that these algorithms must satisfy to be well-defined theoretical objects. I will review how jets are used in searches for new physics and ways in which the substructure of jets is being utilized for discriminating backgrounds from both Standard Model and potential new physics signals. Finally, I will discuss how jets are broadening our knowledge of quantum chromodynamics and how particular measurements performed on jets manifest the universal dynamics of weakly-coupled conformal field theories.

  19. Field Techniques: Atlantic Barrier System. Field Guidebook. National Association of Geology Teachers Eastern Section Annual Field Conference (Lewes, Delaware, April 26-29, 1984).

    ERIC Educational Resources Information Center

    O'Connor, James V., Ed.; Tormey, Brian B., Ed.

    The Atlantic barrier system is used as a focal point in this manual of field exercises. A collection of activities and posed questions provide students with opportunities to develop skills basic to the development of sound field techniques. Investigations can be adapted and modified by teachers to specific subject areas and developmental needs.…

  20. Field analytical techniques for mercury in soils technology evaluation. Topical report, November 1994--March 1997

    SciTech Connect

    Solc, J.; Harju, J.A.; Grisanti, A.A.

    1998-02-01

    This report presents the evaluation of the four field analytical techniques for mercury detection in soils, namely (1) an anodic stripping voltametry technique (ASV) developed and tested by General Electric Corporation; (2) a static headspace analysis (SHSA) technique developed and tested by Dr. Ralph Turner of Oak Ridge National Laboratory; (3) the BiMelyze{reg_sign} Mercury Immunoassay (Bio) developed and tested by BioNebraska, Inc.; and (4) a transportable x-ray fluorescence (XRF) instrument/technique developed and tested by Spectrace, Inc.

  1. Mississippi exploration field trials using microbial, radiometrics, free soil gas, and other techniques

    SciTech Connect

    Moody, J.S.; Brown, L.R.; Thieling, S.C.

    1995-12-31

    The Mississippi Office of Geology has conducted field trials using the surface exploration techniques of geomicrobial, radiometrics, and free soil gas. The objective of these trials is to determine if Mississippi oil and gas fields have surface hydrocarbon expression resulting from vertical microseepage migration. Six fields have been surveyed ranging in depth from 3,330 ft to 18,500 ft. The fields differ in trapping styles and hydrocarbon type. The results so far indicate that these fields do have a surface expression and that geomicrobial analysis as well as radiometrics and free soil gas can detect hydrocarbon microseepage from pressurized reservoirs. All three exploration techniques located the reservoirs independent of depth, hydrocarbon type, or trapping style.

  2. Synchronous in-field application of life-detection techniques in planetary analog missions

    NASA Astrophysics Data System (ADS)

    Amador, Elena S.; Cable, Morgan L.; Chaudry, Nosheen; Cullen, Thomas; Gentry, Diana; Jacobsen, Malene B.; Murukesan, Gayathri; Schwieterman, Edward W.; Stevens, Adam H.; Stockton, Amanda; Yin, Chang; Cullen, David C.; Geppert, Wolf

    2015-02-01

    Field expeditions that simulate the operations of robotic planetary exploration missions at analog sites on Earth can help establish best practices and are therefore a positive contribution to the planetary exploration community. There are many sites in Iceland that possess heritage as planetary exploration analog locations and whose environmental extremes make them suitable for simulating scientific sampling and robotic operations. We conducted a planetary exploration analog mission at two recent lava fields in Iceland, Fimmvörðuháls (2010) and Eldfell (1973), using a specially developed field laboratory. We tested the utility of in-field site sampling down selection and tiered analysis operational capabilities with three life detection and characterization techniques: fluorescence microscopy (FM), adenine-triphosphate (ATP) bioluminescence assay, and quantitative polymerase chain reaction (qPCR) assay. The study made use of multiple cycles of sample collection at multiple distance scales and field laboratory analysis using the synchronous life-detection techniques to heuristically develop the continuing sampling and analysis strategy during the expedition. Here we report the operational lessons learned and provide brief summaries of scientific data. The full scientific data report will follow separately. We found that rapid in-field analysis to determine subsequent sampling decisions is operationally feasible, and that the chosen life detection and characterization techniques are suitable for a terrestrial life-detection field mission. In-field analysis enables the rapid obtainment of scientific data and thus facilitates the collection of the most scientifically relevant samples within a single field expedition, without the need for sample relocation to external laboratories. The operational lessons learned in this study could be applied to future terrestrial field expeditions employing other analytical techniques and to future robotic planetary exploration

  3. Boosted Objects: A Probe of Beyond the Standard Model Physics

    SciTech Connect

    Abdesselam, A.; Kuutmann, E.Bergeaas; Bitenc, U.; Brooijmans, G.; Butterworth, J.; Bruckman de Renstrom, P.; Buarque Franzosi, D.; Buckingham, R.; Chapleau, B.; Dasgupta, M.; Davison, A.; Dolen, J.; Ellis, S.; Fassi, F.; Ferrando, J.; Frandsen, M.T.; Frost, J.; Gadfort, T.; Glover, N.; Haas, A.; Halkiadakis, E.; /more authors..

    2012-06-12

    We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.

  4. Use of amplitude vs offset seismic techniques to delineate subtle stratigraphic traps - Three field studies

    SciTech Connect

    Holton, J.E.; Lausten, C.D.; Blott, J.E. )

    1989-09-01

    Three stratigraphically trapped Wyoming fields which were previously held to be seismically invisible have been examined using amplitude vs. offset seismic techniques. This technology examines the seismic signature changes which take place as a function of source and receiver distance. Such signature changes are directly related to lithology and can be predicted in models and confirmed by the actual data. Two oil fields are located in the Powder River basin: Hartzog Draw and Coyote Creek. The third field, Dripping Rock, is a gas field in the Washakie basin of southwestern Wyoming. The fields produce from sands of the Shannon, Dakota, and Almond formations, respectively. All three fields lack significant velocity differences between the reservoir and trap facies. This results in an inability to delineate the sands using conventional seismic techniques. Amplitude vs. offset techniques, however, present easily identifiable anomalies which reliably delineate the extent of the reservoir sands in each of the cases. Amplitude vs. offset technology has been used successfully in numerous exploratory and development situations throughout the Rocky Mountains and other areas of the US and Canada. It has proven to be a very reliable technique to explore subtle stratigraphic plays which remain relatively immature in mature basins.

  5. A Dosimetric Evaluation of Conventional Helmet Field Irradiation Versus Two-Field Intensity-Modulated Radiotherapy Technique

    SciTech Connect

    Yu, James B.; Shiao, Stephen L.; Knisely, Jonathan . E-mail: jonathan.knisely@yale.edu

    2007-06-01

    Purpose: To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed. Results: Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT. Conclusions: Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients.

  6. Maximizing boosted top identification by minimizing N-subjettiness

    NASA Astrophysics Data System (ADS)

    Thaler, Jesse; van Tilburg, Ken

    2012-02-01

    N -subjettiness is a jet shape designed to identify boosted hadronic objects such as top quarks. Given N subjet axes within a jet, N-subjettiness sums the angular distances of jet constituents to their nearest subjet axis. Here, we generalize and improve on N -subjettiness by minimizing over all possible subjet directions, using a new variant of the k-means clustering algorithm. On boosted top benchmark samples from the BOOST2010 workshop, we demonstrate that a simple cut on the 3-subjettiness to 2-subjettiness ratio yields 20% (50%) tagging efficiency for a 0.23% (4.1%) fake rate, making N -subjettiness a highly effective boosted top tagger. N-subjettiness can be modified by adjusting an angular weighting exponent, and we find that the jet broadening measure is preferred for boosted top searches. We also explore multivariate techniques, and show that additional improvements are possible using a modified Fisher discriminant. Finally, we briefly mention how our minimization procedure can be extended to the entire event, allowing the event shape N-jettiness to act as a fixed N cone jet algorithm.

  7. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Kashyap, Yogesh; Sawhney, Kawal

    2016-03-01

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  8. Pulsed remote eddy current field array technique for nondestructive inspection of ferromagnetic tube

    NASA Astrophysics Data System (ADS)

    Yang, Binfeng; Li, Xuechao

    2010-03-01

    One pick-up coil with a large inner diameter is usually used in pulsed remote field eddy current technique, which decreases the identification ability to defect. With the purpose of overcoming this problem, array pulsed remote field eddy current technique is proposed to enhance the precision in quantification of defect. The finite element method is used to optimise the structure of probe and analyse of the influence effect of response signal with the variation of the defect depths. The results of experimental work confirm that the array pulsed remote field technique has the advantages of high precision and sensitivity, which can be used as an effective method for quantification of defect in tube.

  9. A Technique for Verification of Isocenter Position in Tangential Field Breast Irradiation

    SciTech Connect

    Prabhakar, Ramachandran Pande, Manish; Harsh, Kumar; Julka, Pramod K.; Ganesh, Tharmar; Rath, Goura K.

    2009-04-01

    Treatment verification and reproducibility of the breast treatment portals play a very important role in breast radiotherapy. We propose a simple technique to verify the planned isocenter position during treatment using an electronic portal imaging device. Ten patients were recruited in this study and (CT) computed tomography-based planning was performed with a conventional tangential field technique. For verification purposes, in addition to the standard medial (F1) and lateral (F2) tangential fields, a field (F3) perpendicular to the medial field was used for verification of the treatment portals. Lead markers were placed along the central axis of the 2 defined fields (F1 and F3) and the separation between the markers was measured on the portal images and verified with the marker separation on the digitally reconstructed radiographs (DRRs). Any deviation will identify the shift in the planned isocenter position during treatment. The average deviation observed between the markers measured from the DRR and portal image was 1.6 and 2.1 mm, with a standard deviation of 0.4 and 0.9 mm for fields F1 and F3, respectively. The maximum deviation observed was 3.0 mm for field F3. This technique will be very useful in patient setup for tangential breast radiotherapy.

  10. The Austin Chalk--Drilling and completion techniques-Marcelina Creek Field study

    SciTech Connect

    Betz, C.A.

    1982-09-01

    Exxon Company, U.S.A. has spent considerable time and effort learning how to minimize formation damage in the lost returns prone and clay sensitive Austin Chalk formation. To date, Exxon has successfully drilled 24 Austin Chalk wells in the Marcelina Creek Field in Wilson County, Texas, utilizing a variety of drilling and completion techniques in an effort to determine the optimum method of drilling and completing Austin Chalk wells. This paper describes these different techniques and reviews actual results. Although Exxon has not concluded which drilling and completion technique yields optimum Austin Chalk wells in this field, this paper attempts to develop a correlation between well productivity and the type of drilling and completion technique used.

  11. Offshore Adriatic marginal gas fields: An approach to the technique of reservoir development

    SciTech Connect

    Montanari, A.; Bolelli, V.; Piccoli, G.

    1986-01-01

    The application of accelerated gas blowdown and wire line techniques in reservoir development and exploitation is presented for an off-shore Adriatic marginal gas field. The approach discussed in this paper utilizes selective completion, very low reserves/production ratio, sequential production, Through Tubing Bridge Plug and Through Tubing Perforation techniques to avoid the use of costly workover rigs and to allow economically convenient exploitation of a structure which otherwise would have been abandoned.

  12. SU-E-T-404: Simple Field-In-Field Technique for Total Body Irradiation in Large Patients

    SciTech Connect

    Chi, P; Pinnix, C; Dabaja, B; Wang, C; Aristophanous, M; Tung, S

    2014-06-01

    Purpose: A simple Field-in-Field technique for Total Body Irradiation (TBI) was developed for traditional AP/PA TBI treatments to improve dosimetric uniformity in patients with large separation. Methods: TBI at our institution currently utilizes an AP/PA technique at an extended source-to-surface distance (SSD) of 380cm with patients in left decubitus position during the AP beam and in right decubitus during the PA beam. Patients who have differences in thickness (separation) between the abdomen and head greater than 10cm undergo CT simulation in both left and right decubitus treatment positions. One plan for each CT is generated to evaluate dose to patient midline with both AP and PA fields, but only corresponding AP fields will be exported for treatment for patient left decubitus position and PA fields for patient right decubitus position. Subfields are added by collimating with the x-ray jaws according to separation changes at 5–7% steps to minimize hot regions to less than 10%. Finally, the monitor units (MUs) for the plans are verified with hand calculation and water phantom measurements. Results: Dose uniformity (+/−10%) is achieved with field-in-field using only asymmetric jaws. It is dosimetrically robust with respect to minor setup/patient variations inevitable due to patient conditions. MUs calculated with Pinnacle were verified in 3 clinical cases and only a 2% difference was found compared to homogeneous calculation. In-vivo dosimeters were also used to verify doses received by each patient with and confirmed dose variations less than 10%. Conclusion: We encountered several cases with separation differences that raised uniformity concerns — based on a 1% dose difference per cm separation difference assumption. This could Resultin an unintended hot spot, often in the head/neck, up to 25%. This method allows dose modulation without adding treatment complexity nor introducing radiobiological variations, providing a reasonable solution for this unique

  13. Three-dimensional radar imaging techniques and systems for near-field applications

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.; McMakin, Douglas L.; Jones, A. Mark; Tedeschi, Jonathan R.

    2016-05-01

    The Pacific Northwest National Laboratory has developed three-dimensional holographic (synthetic aperture) radar imaging techniques and systems for a wide variety of near-field applications. These applications include radar crosssection (RCS) imaging, personnel screening, standoff concealed weapon detection, concealed threat detection, throughbarrier imaging, ground penetrating radar (GPR), and non-destructive evaluation (NDE). Sequentially-switched linear arrays are used for many of these systems to enable high-speed data acquisition and 3-D imaging. In this paper, the techniques and systems will be described along with imaging results that demonstrate the utility of near-field 3-D radar imaging for these compelling applications.

  14. Application of the TLD albedo technique for monitoring and interpretation of neutron stray radiation fields

    NASA Astrophysics Data System (ADS)

    Piesch, E.; Burgkhardt, B.

    1980-09-01

    A single sphere albedo technique with TLD 600/TLD 700 detectors has been applied in neutron monitoring to calibrate albedo dosimeters and to interpret neutron stray radiation fields in terms of neutron dose equivalent separated for the energy groups below 0.4 eV, 0.4-10 keV and 10 keV-10 MeV, and Eeff for fast neutrons. The paper describes the technique for field and personnel monitoring under the aspect of an on-line computer program for data recording and processing.

  15. Technique development for field inspection of cracking in seam welded ducts

    SciTech Connect

    Shell, Eric B.; Benson, Craig; Liljestrom, Greg C.; Shanahan, Stephen

    2014-02-18

    The resistance seam weld interfaces between alloyed and pure titanium are an in service concern due to precipitation of titanium hydride and resulting embrittlement and cracking. Several inspection techniques were developed and evaluated for field use to characterize the damage in the fleet. Electromagnetic, ultrasonic, florescent penetrant, thermographic, and radiographic techniques were considered. The ultrasonic and electromagnetic approaches were both found suitable. However, the electromagnetic approach is more desirable for field inspections, due to consistency and ease of use. The electromagnetic inspection procedure is able to discriminate between precursor damage and through cracking with sufficient sensitivity to small cracks.

  16. Technique development for field inspection of cracking in seam welded ducts

    NASA Astrophysics Data System (ADS)

    Shell, Eric B.; Liljestrom, Greg C.; Benson, Craig; Shanahan, Stephen

    2014-02-01

    The resistance seam weld interfaces between alloyed and pure titanium are an in service concern due to precipitation of titanium hydride and resulting embrittlement and cracking. Several inspection techniques were developed and evaluated for field use to characterize the damage in the fleet. Electromagnetic, ultrasonic, florescent penetrant, thermographic, and radiographic techniques were considered. The ultrasonic and electromagnetic approaches were both found suitable. However, the electromagnetic approach is more desirable for field inspections, due to consistency and ease of use. The electromagnetic inspection procedure is able to discriminate between precursor damage and through cracking with sufficient sensitivity to small cracks.

  17. A Magnetohydrodynamic Boost for Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Mizuno, Yosuke; Hardee, Philip; Hartmann, dieter; Nishikwa, Ken-Ichi; Zhang, Bing

    2006-01-01

    We have performed relativistic magnetohydrodynamic simulations of the hydrodynamic boosting mechanism for relativistic jets explored by Aloy & Rezzolla (2006) using the RAISHIN code. Simulation results show that the presence of a magnetic field may change the properties of the shock interface between the tenuous, overpressured jet (V(sub j) (sup z)) flowing tangentially to a dense external medium. Magnetic fields can lead to more efficient acceleration of the jet, in comparison to the pure-hydrodynamic case. A poloidal magnetic field (B(sup z)), tangent to the interface and parallel to the jet flow, produces both a stronger outward moving shock and inward moving rarefaction wave. This leads to a large velocity component normal to the interface in addition to acceleration tangent to the interface, and the jet is thus accelerated to a larger Lorentz factors than those obtained in the pure-hydrodynamic case. In contrast, a strong toroidal magnetic field (B(sup y)), tangent to the interface but perpendicular to the jet flow, also leads to stronger acceleration tangent to the shock interface relative to the pure-hydrodynamic case, but to a lesser extent than found for the poloidal case due to the fact that the velocity component normal to the shock interface is now much smaller. Overall, the acceleration efficiency in the toroidal case is less than that of the poloidal case but both geometries still result in higher Lorentz factors than the pure-hydrodynamic case. Thus, the presence and relative orientation of a magnetic field in relativistic jets can have a significant influence on the hydrodynamic boost mechanism studied by Aloy & Rezzolla (2006).

  18. Hyphenated low-field NMR techniques: combining NMR with NIR, GPC/SEC and rheometry.

    PubMed

    Räntzsch, Volker; Wilhelm, Manfred; Guthausen, Gisela

    2016-06-01

    Hyphenated low-field NMR techniques are promising characterization methods for online process analytics and comprehensive offline studies of soft materials. By combining different analytical methods with low-field NMR, information on chemical and physical properties can be correlated with molecular dynamics and complementary chemical information. In this review, we present three hyphenated low-field NMR techniques: a combination of near-infrared spectroscopy and time-domain NMR (TD-NMR) relaxometry, online (1) H-NMR spectroscopy measured directly after size exclusion chromatographic (SEC, also known as GPC) separation and a combination of rheometry and TD-NMR relaxometry for highly viscous materials. Case studies are reviewed that underline the possibilities and challenges of the different hyphenated low-field NMR methods. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25854997

  19. General Matrix Inversion Technique for the Calibration of Electric Field Sensor Arrays on Aircraft Platforms

    NASA Technical Reports Server (NTRS)

    Mach, D. M.; Koshak, W. J.

    2007-01-01

    A matrix calibration procedure has been developed that uniquely relates the electric fields measured at the aircraft with the external vector electric field and net aircraft charge. The calibration method can be generalized to any reasonable combination of electric field measurements and aircraft. A calibration matrix is determined for each aircraft that represents the individual instrument responses to the external electric field. The aircraft geometry and configuration of field mills (FMs) uniquely define the matrix. The matrix can then be inverted to determine the external electric field and net aircraft charge from the FM outputs. A distinct advantage of the method is that if one or more FMs need to be eliminated or deemphasized [e.g., due to a malfunction), it is a simple matter to reinvert the matrix without the malfunctioning FMs. To demonstrate the calibration technique, data are presented from several aircraft programs (ER-2, DC-8, Altus, and Citation).

  20. Computational Diagnostic Techniques for Electromagnetic Scattering: Analytical Imaging, Near Fields, and Surface Currents

    NASA Technical Reports Server (NTRS)

    Hom, Kam W.; Talcott, Noel A., Jr.; Shaeffer, John

    1997-01-01

    This paper presents three techniques and the graphics implementations which can be used as diagnostic aides in the design and understanding of scattering structures: Imaging, near fields, and surface current displays. The imaging analysis is a new bistatic k space approach which has potential for much greater information than standard experimental approaches. The near field and current analysis are implementations of standard theory while the diagnostic graphics displays are implementations exploiting recent computer engineering work station graphics libraries.

  1. Near-Field Three-Dimensional Radar Imaging Techniques and Applications

    SciTech Connect

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    2010-07-01

    Three dimensional radio frequency imaging techniques have been developed for a variety of near field applications including radar cross-section imaging, concealed weapon detection, ground penetrating radar imaging, through-barrier imaging, and non-destructive evaluation. These methods employ active radar transceivers that operate at various frequency ranges covering a wide range from less than 100 MHz to in excess of 350 GHz with the frequency range customized for each application. Computational wavefront reconstruction imaging techniques have been developed that optimize the resolution and illumination quality of the images. In this paper, rectilinear and cylindrical three-dimensional imaging techniques are described along with several application results.

  2. On Electromagnetic Field-to-Wire Coupling Versus Conducted Injection Techniques

    NASA Technical Reports Server (NTRS)

    Javor, Ken

    1997-01-01

    Since the inception of conducted injection techniques to model radiated susceptibility/immunity coupling, considerable debate has ensued regarding its validity. This paper affirms the viewpoint of Szentkuti, (1989) builds upon test results of Adams (1992) and Trout (1996), and discusses Perini's theoretical observations (1993, 1995A, 1995B). Analytical and test results are presented which further demonstrate under what specific conditions conducted and radiated techniques can be correlated, and how the work of Adams, Trout, and Perini fits into the general problem of modeling field-to-wire coupling. At frequencies where transmission line and antenna effects are minimal, conducted immunity techniques provide excellent correlation with analytical and empirical predictions of radiated coupling. From a practical standpoint, conducted injection techniques provide realistic coupling at frequencies and amplitude levels that would be uneconomical to achieve with traditional radiated techniques.

  3. A multiview boosting approach to tissue segmentation

    NASA Astrophysics Data System (ADS)

    Kwak, Jin Tae; Xu, Sheng; Pinto, Peter A.; Turkbey, Baris; Bernardo, Marcelino; Choyke, Peter L.; Wood, Bradford J.

    2014-04-01

    Digitized histopathology images have a great potential for improving or facilitating current assessment tools in cancer pathology. In order to develop accurate and robust automated methods, the precise segmentation of histologic objects such epithelium, stroma, and nucleus is necessary, in the hopes of information extraction not otherwise obvious to the subjective eye. Here, we propose a multivew boosting approach to segment histology objects of prostate tissue. Tissue specimen images are first represented at different scales using a Gaussian kernel and converted into several forms such HSV and La*b*. Intensity- and texture-based features are extracted from the converted images. Adopting multiview boosting approach, we effectively learn a classifier to predict the histologic class of a pixel in a prostate tissue specimen. The method attempts to integrate the information from multiple scales (or views). 18 prostate tissue specimens from 4 patients were employed to evaluate the new method. The method was trained on 11 tissue specimens including 75,832 epithelial and 103,453 stroma pixels and tested on 55,319 epithelial and 74,945 stroma pixels from 7 tissue specimens. The technique showed 96.7% accuracy, and as summarized into a receiver operating characteristic (ROC) plot, the area under the ROC curve (AUC) of 0.983 (95% CI: 0.983-0.984) was achieved.

  4. Development of an expanded-field irradiation technique using a gimbaled x-ray head

    SciTech Connect

    Ono, Tomohiro; Miyabe, Yuki Yamada, Masahiro; Yokota, Kenji; Kaneko, Shuji; Monzen, Hajime; Mizowaki, Takashi; Hiraoka, Masahiro; Sawada, Akira; Kokubo, Masaki

    2014-10-15

    Purpose: The Vero4DRT has a maximum field size of 150.0 × 150.0 mm. The purpose of the present study was to develop expanded-field irradiation techniques using the unique gimbaled x-ray head of the Vero4DRT and to evaluate the dosimetric characteristics thereof. Methods: Two techniques were developed. One features gimbal swing irradiation and multiple static segments consisting of four separate fields exhibiting 2.39° gimbal rotation around two orthogonal axes. The central beam axis for each piecewise-field is shifted 40 mm from the isocenters of the left–right (LR) and superior–inferior (SI) directions, and, thus, the irradiation field size is expanded to 230.8 × 230.8 mm. Adjacent regions were created at the isocenter (a center-adjacent expandedfield) and 20 mm from the isocenter (an off-adjacent expandedfield). The field gaps or overlaps of combined piecewise-fields were established by adjustment of gimbal rotation and movement of the multileaf collimator (MLC). Another technique features dynamic segment irradiation in which the beam is delivered while rotating the gimbal. The dose profile is controlled by a combination of gimbal swing motion and opening and closing of the MLC. This enabled the authors to expand the irradiation field on the LR axis because the direction of MLC motion is parallel to that axis. A field 220.6 × 150.0 mm in dimensions was configured and examined. To evaluate the dosimetric characteristics of the expandedfields, films inserted into water-equivalent phantoms at depths of 50, 100, and 150 mm were irradiated and field sizes, penumbrae, flatness, and symmetry analyzed. In addition, the expanded-field irradiation techniques were applied to intensity-modulated radiation therapy (IMRT). A head-and-neck IMRT field, created using a conventional Linac (the Varian Clinac iX), was reproduced employing an expanded-field of the Vero4DRT. The simulated dose distribution for the expanded-IMRT field was compared to the measured

  5. A novel potential/viscous flow coupling technique for computing helicopter flow fields

    NASA Technical Reports Server (NTRS)

    Summa, J. Michael; Strash, Daniel J.; Yoo, Sungyul

    1990-01-01

    Because of the complexity of helicopter flow field, a zonal method of analysis of computational aerodynamics is required. Here, a new procedure for coupling potential and viscous flow is proposed. An overlapping, velocity coupling technique is to be developed with the unique feature that the potential flow surface singularity strengths are obtained directly from the Navier-Stokes at a smoother inner fluid boundary. The closed-loop iteration method proceeds until the velocity field is converged. This coupling should provide the means of more accurate viscous computations of the near-body and rotor flow fields with resultant improved analysis of such important performance parameters as helicopter fuselage drag and rotor airloads.

  6. About the parametrizations utilized to perform magnetic moments measurements using the transient field technique

    NASA Astrophysics Data System (ADS)

    Gómez, A. M.; Torres, D. A.

    2016-07-01

    The experimental study of nuclear magnetic moments, using the Transient Field technique, makes use of spin-orbit hyperfine interactions to generate strong magnetic fields, above the kilo-Tesla regime, capable to create a precession of the nuclear spin. A theoretical description of such magnetic fields is still under theoretical research, and the use of parametrizations is still a common way to address the lack of theoretical information. In this contribution, a review of the main parametrizations utilized in the measurements of Nuclear Magnetic Moments will be presented, the challenges to create a theoretical description from first principles will be discussed.

  7. Design of Optical Systems with Extended Depth of Field: An Educational Approach to Wavefront Coding Techniques

    ERIC Educational Resources Information Center

    Ferran, C.; Bosch, S.; Carnicer, A.

    2012-01-01

    A practical activity designed to introduce wavefront coding techniques as a method to extend the depth of field in optical systems is presented. The activity is suitable for advanced undergraduate students since it combines different topics in optical engineering such as optical system design, aberration theory, Fourier optics, and digital image…

  8. Program Evaluation and Review Technique (PERT): A Planning and Control Tool for Occupational Field Studies.

    ERIC Educational Resources Information Center

    Hemphill, John M., Jr.; And Others

    Program Evaluation and Review Technique (PERT) is used in the U.S. Marine Corps task analysis program for occupational field studies. Scheduling sequential tasks, estimating time requirements, determining staffing needs, and locating checkpoints for control all can be accomplished using PERT. Examples of operational aspects of PERT, PERT…

  9. A Field-Based Technique for Teaching about Habitat Fragmentation and Edge Effects

    ERIC Educational Resources Information Center

    Resler, Lynn M.; Kolivras, Korine N.

    2009-01-01

    This article presents a field technique that exposes students to the indirect effects of habitat fragmentation on plant distributions through studying edge effects. This assignment, suited for students in an introductory biogeography or resource geography class, increases students' knowledge of basic biogeographic concepts such as environmental…

  10. Application of the wide-field shadowgraph technique to rotor wake visualization

    NASA Technical Reports Server (NTRS)

    Norman, Thomas R.; Light, Jeffrey S.

    1989-01-01

    The wide field shadowgraph technique is reviewed along with its application to the visualization of rotor wakes. In particular, current experimental methods and data reduction requirements are discussed. Sample shadowgraphs are presented. These include shadowgraphs of model-scale helicopter main rotors and tilt rotors, and full scale tail rotors, both in hover and in forward flight.

  11. Integrated velocity field from ground and satellite geodetic techniques: application to Arenal volcano

    NASA Astrophysics Data System (ADS)

    Muller, Cyril; del Potro, Rodrigo; Biggs, Juliet; Gottsmann, Joachim; Ebmeier, Susanna K.; Guillaume, Sébastien; Cattin, Paul-Henri; Van der Laat, Rodolfo

    2015-02-01

    Measurements of ground deformation can be used to identify and interpret geophysical processes occurring at volcanoes. Most studies rely on a single geodetic technique, or fit a geophysical model to the results of multiple geodetic techniques. Here we present a methodology that combines GPS, Total Station measurements and InSAR into a single reference frame to produce an integrated 3-D geodetic velocity surface without any prior geophysical assumptions. The methodology consists of five steps: design of the network, acquisition and processing of the data, spatial integration of the measurements, time series computation and finally the integration of spatial and temporal measurements. The most significant improvements of this method are (1) the reduction of the required field time, (2) the unambiguous detection of outliers, (3) an increased measurement accuracy and (4) the construction of a 3-D geodetic velocity field. We apply this methodology to ongoing motion on Arenal's western flank. Integration of multiple measurement techniques at Arenal volcano revealed a deformation field that is more complex than that described by individual geodetic techniques, yet remains consistent with previous studies. This approach can be applied to volcano monitoring worldwide and has the potential to be extended to incorporate other geodetic techniques and to study transient deformation.

  12. Solar coronal magnetic fields derived using seismology techniques applied to omnipresent sunspot waves

    NASA Astrophysics Data System (ADS)

    Jess, David B.; Reznikova, Veronika E.; Ryans, Robert S. I.; Christian, Damian J.; Keys, Peter H.; Mathioudakis, Mihalis; Mackay, Duncan H.; Krishna Prasad, S.; Banerjee, Dipankar; Grant, Samuel D. T.; Yau, Sean; Diamond, Conor

    2016-02-01

    Sunspots on the surface of the Sun are the observational signatures of intense manifestations of tightly packed magnetic field lines, with near-vertical field strengths exceeding 6,000 G in extreme cases. It is well accepted that both the plasma density and the magnitude of the magnetic field strength decrease rapidly away from the solar surface, making high-cadence coronal measurements through traditional Zeeman and Hanle effects difficult as the observational signatures are fraught with low-amplitude signals that can become swamped with instrumental noise. Magneto-hydrodynamic (MHD) techniques have previously been applied to coronal structures, with single and spatially isolated magnetic field strengths estimated as 9-55 G (refs ,,,). A drawback with previous MHD approaches is that they rely on particular wave modes alongside the detectability of harmonic overtones. Here we show, for the first time, how omnipresent magneto-acoustic waves, originating from within the underlying sunspot and propagating radially outwards, allow the spatial variation of the local coronal magnetic field to be mapped with high precision. We find coronal magnetic field strengths of 32 +/- 5 G above the sunspot, which decrease rapidly to values of approximately 1 G over a lateral distance of 7,000 km, consistent with previous isolated and unresolved estimations. Our results demonstrate a new, powerful technique that harnesses the omnipresent nature of sunspot oscillations to provide magnetic field mapping capabilities close to a magnetic source in the solar corona.

  13. Unusual well control techniques pay off. [Well drilling techniques in the Elgin gas condensate field, North Sea

    SciTech Connect

    Idelovici, J.L.

    1993-07-01

    Well control and completion operations were seriously complicated by an unusual pressure phenomena encountered while drilling an appraisal well through Jurassic sandstones in a high-pressure, high-temperature (HPHT), gas and condensate field located in the United Kingdom continental shelf. The HPHT sandstone reservoir is located in the Upper Jurassic Franklin formation. Unorthodox well-control techniques were used because it was determined that the abnormally high pressure was generated by a mechanical reaction of the rock under the effect of heavy mud and equivalent circulating density, rather than by entry into the wellbore of formation fluids. This paper reviews the complex drilling fluid control procedures which had to be utilized to maintain an open bore hole during drilling.

  14. Increased Oil Production and Reserves From Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah

    SciTech Connect

    Morgan, C.D.; Deo, M.D.

    1998-04-01

    The Bluebell field is productive from the Tertiary lower Green River and Colton (Wasatch) Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in the ancestral Lake Uinta. Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1000 to 3000 vertical ft (300-900 m), then stimulating the entire interval with hydrochloric acid. This technique is often referred to as the shot gun completion. Completion techniques used in the Bluebell field were discussed in detail in the Second Annual Report (Curtice, 1996). The shot-gun technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. A two-year characterization study involved detailed examination of outcrop, core, well logs, surface and subsurface fractures, produced oil-field waters, engineering parameters of the two demonstration wells, and analysis of past completion techniques and effectiveness. The study was intended to improve the geologic characterization of the producing formations and thereby develop completion techniques specific to the producing beds or facies instead of a shot gun approach to stimulating all the beds. The characterization did not identify predictable-facies or predictable-fracture trends within the vertical stratigraphic column as originally hoped. Advanced logging techniques can identify productive beds in individual wells. A field-demonstration program was developed to use cased-hole advanced logging techniques in two wells and recompletion the wells at two different scales based on the logging. The first well was going to be completed at the interval scale using a multiple stage completion technique (about 500 ft [150 m] per stage). The second well will be recompleted at the bed-scale using bridge plug and packer to isolate three or more

  15. [African silhouettes and field photography. M. Griaule's contribution to the Maussian "discovery" of body techniques].

    PubMed

    Despoix, Philippe

    2010-01-01

    This essay focuses on the interaction between the new reproduction media and corresponding reconfiguration of research fields in anthropology using the case of the "techniques of the body" - a concept developed by Marcel Mauss (1872-1950). For Mauss, the initiator of this discipline in France, body skills constituted the most important anthropological entity resulting from the confrontation of technical images and his interest in walking techniques. Three scenarios are especially significant for Mauss's formulation of "body techniques" as a genuine concept: the front during the World War I, a New Yorke hospital in 1926, and an ethnographical field study conducted in Africa during the ate 1920s. Both, the photographic media as well as the Abyssinian expedition of his student Marcel Griaule, whose research publication Mauss co-authored (Silhouettes et graffiti abyssins) n 1933, take centre stage here. PMID:21249525

  16. Investigation of 2D-Trace Gas Field Reconstruction Techniques From Tomographic AMAX-DOAS Measurements

    NASA Astrophysics Data System (ADS)

    Laepple, T.; Heue, K.; Friedeburg, C. V.; Wang, P.; Knab, V.; Pundt, I.

    2002-12-01

    Tomographic-Differential-Optical-Absorption-Spectroscopy (Tom-DOAS) is a new application of the DOAS method designed to measure 2-3-dimensional concentration fields of different trace gases (e.g. NO2, HCHO, Ozone) in the troposphere. Numerical reconstruction techniques are used to obtain spatially resolved data from the slant column densities provided by DOAS instruments. We discuss the detection of emission plumes by AMAX (Airborne Multi AXis) DOAS Systems which measure sunlight by telescopes pointing in different directions. 2D distributions are reconstructed from slant columns by using airmass factor matrices and inversion techniques. We discuss possibilities and limitations of this technique gained with the use of simulated test fields. Therefore the effect of the parameter choice (e.g. flight track, algorithm changes) and measurement errors is investigated. Further, first results from the Partenavia aircraft measurements over Milano (Italy) during the European FORMAT campaign will be presented.

  17. Second Harmonic Technique for Thermal Conductivity Measurement in a Pulsed Magnetic Field

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoko; Betts, Jonathan B.; Migliori, Albert

    2009-03-01

    We describe a second-harmonic technique to be used eventually to probe the thermal conductivity of LSCO with superconductivity suppressed by high magnetic fields. The technique is suitable for the high-noise environment of pulsed magnets. Unlike the 3φ technique, a heater and a thermometer are mounted separately. Therefore, the 2φ signal is the dominant signal in the thermometer output. The frequencies are chosen so that the thermal penetration depth is smaller than the sample thickness. The thermometer response time and thermal impedance associated with material interfaces are carefully tested and compared to calculation. The calculations are based on exact solutions of the full bulk heat transport equations and produce results different from the lumped-constant approximations often used in ac calorimetry. Work performed under the auspices of the National High Magnetic Field Laboratory.

  18. A Rapid, Fluorescence-Based Field Screening Technique for Organic Species in Soil and Water Matrices.

    PubMed

    Russell, Amber L; Martin, David P; Cuddy, Michael F; Bednar, Anthony J

    2016-06-01

    Real-time detection of hydrocarbon contaminants in the environment presents analytical challenges because traditional laboratory-based techniques are cumbersome and not readily field portable. In the current work, a method for rapid and semi-quantitative detection of organic contaminants, primarily crude oil, in natural water and soil matrices has been developed. Detection limits in the parts per million and parts per billion were accomplished when using visual and digital detection methods, respectively. The extraction technique was modified from standard methodologies used for hydrocarbon analysis and provides a straight-forward separation technique that can remove interference from complex natural constituents. For water samples this method is semi-quantitative, with recoveries ranging from 70 % to 130 %, while measurements of soil samples are more qualitative due to lower extraction efficiencies related to the limitations of field-deployable procedures. PMID:26988223

  19. Direct imaging of neural currents using ultra-low field magnetic resonance techniques

    DOEpatents

    Volegov, Petr L.; Matlashov, Andrei N.; Mosher, John C.; Espy, Michelle A.; Kraus, Jr., Robert H.

    2009-08-11

    Using resonant interactions to directly and tomographically image neural activity in the human brain using magnetic resonance imaging (MRI) techniques at ultra-low field (ULF), the present inventors have established an approach that is sensitive to magnetic field distributions local to the spin population in cortex at the Larmor frequency of the measurement field. Because the Larmor frequency can be readily manipulated (through varying B.sub.m), one can also envision using ULF-DNI to image the frequency distribution of the local fields in cortex. Such information, taken together with simultaneous acquisition of MEG and ULF-NMR signals, enables non-invasive exploration of the correlation between local fields induced by neural activity in cortex and more `distant` measures of brain activity such as MEG and EEG.

  20. Two-field versus three-field irradiation technique in the postoperative treatment of head-and-neck cancer

    SciTech Connect

    Yom, Sue S.; Morrison, William H.; Ang, K. Kian; Rosenthal, David I.; Perkins, George H.; Wong, Pei-Fong M.S.; Garden, Adam S. . E-mail: agarden@mdanderson.org

    2006-10-01

    Purpose: We have increasingly used a two-field noncoplanar 'caudal tilt' technique (CTT) for irradiating postlaryngectomy and pharyngectomy patients to avoid matchline problems that can be encountered with the classic three-field head-and-neck radiation technique (3FT). This report compares the clinical outcomes of patients treated with postoperative radiation (PORT) using either 3FT or CTT. Methods and Materials: We conducted a retrospective review of the medical records of all patients with laryngeal or hypopharyngeal cancers consecutively treated with PORT between 1997 and 2002. Three-dimensional dosimetric planning was carried out for all patients. Results: Of 91 patients, 39 were treated with 3FT and 52 with CTT. The median follow-up was 34 months. Estimated rates of 2-year locoregional control, disease-free survival, and overall survival for patients treated with 3FT and CTT were, respectively, 92% and 85% (p = 0.241), 62% and 55% (p = 0.497), and 77% and 72% (p = 0.616). There were no significant differences in the incidence of acute or late side effects in the two groups. Conclusions: 'Caudal tilt' technique is often used as an alternative to 3FT for postoperative radiotherapy in cases of greater medical and technical complexity. Despite its use in more challenging cases, CTT provides similar long-term clinical outcomes compared with standard 3FT, when computerized three-dimensional dosimetry is used to assure adequate dosimetry throughout the treated volume.

  1. Patch nearfield acoustic holography combined with sound field separation technique applied to a non-free field

    NASA Astrophysics Data System (ADS)

    Bi, ChuanXing; Jing, WenQian; Zhang, YongBin; Xu, Liang

    2015-02-01

    The conventional nearfield acoustic holography (NAH) is usually based on the assumption of free-field conditions, and it also requires that the measurement aperture should be larger than the actual source. This paper is to focus on the problem that neither of the above-mentioned requirements can be met, and to examine the feasibility of reconstructing the sound field radiated by partial source, based on double-layer pressure measurements made in a non-free field by using patch NAH combined with sound field separation technique. And also, the sensitivity of the reconstructed result to the measurement error is analyzed in detail. Two experiments involving two speakers in an exterior space and one speaker inside a car cabin are presented. The experimental results demonstrate that the patch NAH based on single-layer pressure measurement cannot obtain a satisfied result due to the influences of disturbing sources and reflections, while the patch NAH based on double-layer pressure measurements can successfully remove these influences and reconstruct the patch sound field effectively.

  2. Three-dimensional near-field MIMO array imaging using range migration techniques.

    PubMed

    Zhuge, Xiaodong; Yarovoy, Alexander G

    2012-06-01

    This paper presents a 3-D near-field imaging algorithm that is formulated for 2-D wideband multiple-input-multiple-output (MIMO) imaging array topology. The proposed MIMO range migration technique performs the image reconstruction procedure in the frequency-wavenumber domain. The algorithm is able to completely compensate the curvature of the wavefront in the near-field through a specifically defined interpolation process and provides extremely high computational efficiency by the application of the fast Fourier transform. The implementation aspects of the algorithm and the sampling criteria of a MIMO aperture are discussed. The image reconstruction performance and computational efficiency of the algorithm are demonstrated both with numerical simulations and measurements using 2-D MIMO arrays. Real-time 3-D near-field imaging can be achieved with a real-aperture array by applying the proposed MIMO range migration techniques. PMID:22345541

  3. Boost IORT in Breast Cancer: Body of Evidence

    PubMed Central

    Sedlmayer, Felix; Reitsamer, Roland; Fussl, Christoph; Ziegler, Ingrid; Deutschmann, Heinz; Kopp, Peter

    2014-01-01

    The term IORT (intraoperative radiotherapy) is currently used for various techniques that show decisive differences in dose delivery. The largest evidence for boost IORT preceding whole breast irradiation (WBI) originates from intraoperative electron treatments with single doses around 10 Gy, providing outstandingly low local recurrence rates in any risk constellation also at long term analyses. Compared to other boost methods, an intraoperative treatment has evident advantages as follows. Precision. Direct visualisation of the tumour bed during surgery guarantees an accurate dose delivery. This fact has additionally gained importance in times of primary reconstruction techniques after lumpectomy to optimise cosmetic outcome. IORT is performed before breast tissue is mobilised for plastic purposes. Cosmesis. As a consequence of direct tissue exposure without distension by hematoma/seroma, IORT allows for small treatment volumes and complete skin sparing, both having a positive effect on late tissue tolerance and, hence, cosmetic appearance. Patient Comfort. Boost IORT marginally prolongs the surgical procedure, while significantly shortening postoperative radiotherapy. Its combination with a 3-week hypofractionated external beam radiotherapy to the whole breast (WBI) is presently tested in the HIOB trial (hypofractionated WBI preceded by IORT electron boost), a prospective multicenter trial of the International Society of Intraoperative Radiotherapy (ISIORT). PMID:25258684

  4. A technique for simulating visual field losses in virtual environments to study human navigation.

    PubMed

    Fortenbaugh, Francesca C; Hicks, John C; Hao, Lei; Turano, Kathleen A

    2007-08-01

    The following paper describes a new technique for simulating peripheral field losses in virtual environments to study the roles of the central and peripheral visual fields during navigation. Based on Geisler and Perry's (2002) gaze-contingent multiresolution display concept, the technique extends their methodology to work with three-dimensional images that are both transformed and rendered in real time by a computer graphics system. In order to assess the usefulness of this method for studying visual field losses, an experiment was run in which seven participants were required to walk to a target tree in a virtual forest as quickly and efficiently as possible while artificial head and eye-based delays were systematically introduced. Bilinear fits were applied to the mean trial times in order to assess at what delay lengths breaks in performance could be observed. Results suggest that breaks occur beyond the current delays inherent in the system. Increases in trial times across all delays tested were also observed when simulated peripheral field losses were applied compared to full FOV conditions. Possible applications and limitations of the system are discussed. The source code needed to program visual field losses can be found at lions.med.jhu.edu/archive/turanolab/Simulated_Visual_Field_Loss_Code.html. PMID:17958167

  5. Local determination of ionospheric electric fields from coherent scatter radar data using the SECS technique

    NASA Astrophysics Data System (ADS)

    Amm, O.; Grocott, A.; Lester, M.; Yeoman, T.

    2009-04-01

    Due to the variable spatio-temporal availability of backscatter from ionospheric coherent scatter radars like SuperDARN or STARE, merging the line-of-sight data of ionospheric plasma velocities that are measured by the radars to spatial maps of such velocities or of electric fields is a non-trivial task. Often this task is solved in a way that statistical a priori information about the global ionospheric electric potential is used in addition to the actual measured data, in order to compensate for lack of measurements in certain regions. However, the disadvantage of such a solution is that the influence of the a priori model may get strong or even dominating the results, in which cases it is hard to determine how well the resulting electric field represents the actual situation for a given point of time and space. Spherical elementary currents systems (SECS) are basis functions that can describe any continuously differentiable vector field on a sphere. Originally, they have successfully been applied to model ionospheric currents based on ground and spacecraft magnetic field data, which explains the historical notion of "current systems" in the name. We present a new technique based on SECS that allows to model distributions of ionospheric plasma flows or electric fields based on coherent scatter radar data of line-of-sight plasma flows without any additional statistical a priori assumptions, on a local region within which the backscatter availability was moderate to good. This region can have any shape and does not need to have boundaries along constant latitude or longitude. Using a synthetic electric field model and variable backscatter availability levels to create input data sets, we test how well the technique is able to reconstruct the original electric field, as a function of available backscatter. Finally, the application of the technique is demonstrated for real data cases, measured by the CUTLASS radars over northern Europe.

  6. Boosted top quarks and jet structure

    NASA Astrophysics Data System (ADS)

    Schätzel, Sebastian

    2015-09-01

    The Large Hadron Collider is the first particle accelerator that provides high enough energy to produce large numbers of boosted top quarks. The decay products of these top quarks are confined to a cone in the top quark flight direction and can be clustered into a single jet. Top quark reconstruction then amounts to analysing the structure of the jet and looking for subjets that are kinematically compatible with top quark decay. Many techniques have been developed in this context to identify top quarks in a large background of non-top jets. This article reviews the results obtained using data recorded in the years 2010-2012 by the experiments ATLAS and CMS. Studies of Standard Model top quark production and searches for new massive particles that decay to top quarks are presented.

  7. A simple technique for measuring buoyant weight increment of entire, transplanted coral colonies in the field

    PubMed Central

    Herler, Jürgen; Dirnwöber, Markus

    2011-01-01

    Estimating the impacts of global and local threats on coral reefs requires monitoring reef health and measuring coral growth and calcification rates at different time scales. This has traditionally been mostly performed in short-term experimental studies in which coral fragments were grown in the laboratory or in the field but measured ex situ. Practical techniques in which growth and measurements are performed over the long term in situ are rare. Apart from photographic approaches, weight increment measurements have also been applied. Past buoyant weight measurements under water involved a complicated and little-used apparatus. We introduce a new method that combines previous field and laboratory techniques to measure the buoyant weight of entire, transplanted corals under water. This method uses an electronic balance fitted into an acrylic glass underwater housing and placed atop of an acrylic glass cube. Within this cube, corals transplanted onto artificial bases can be attached to the balance and weighed at predetermined intervals while they continue growth in the field. We also provide a set of simple equations for the volume and weight determinations required to calculate net growth rates. The new technique is highly accurate: low error of weight determinations due to variation of coral density (< 0.08%) and low standard error (< 0.01%) for repeated measurements of the same corals. We outline a transplantation technique for properly preparing corals for such long-term in situ experiments and measurements. PMID:22049248

  8. A New Technique for the Photospheric Driving of Non-potential Solar Coronal Magnetic Field Simulations

    NASA Astrophysics Data System (ADS)

    Weinzierl, Marion; Yeates, Anthony R.; Mackay, Duncan H.; Henney, Carl J.; Arge, C. Nick

    2016-05-01

    In this paper, we develop a new technique for driving global non-potential simulations of the Sun’s coronal magnetic field solely from sequences of radial magnetic maps of the solar photosphere. A primary challenge to driving such global simulations is that the required horizontal electric field cannot be uniquely determined from such maps. We show that an “inductive” electric field solution similar to that used by previous authors successfully reproduces specific features of the coronal field evolution in both single and multiple bipole simulations. For these cases, the true solution is known because the electric field was generated from a surface flux-transport model. The match for these cases is further improved by including the non-inductive electric field contribution from surface differential rotation. Then, using this reconstruction method for the electric field, we show that a coronal non-potential simulation can be successfully driven from a sequence of ADAPT maps of the photospheric radial field, without including additional physical observations which are not routinely available.

  9. Determination of internal friction using ultrasonic diffuse field and resonance techniques

    NASA Astrophysics Data System (ADS)

    Panetta, P. D.; Johnson, Ward

    2000-05-01

    Attempts to nondestructively determine mechanical properties of metals and alloys have traditionally focused on empirical correlations or relied on models using static microstructural parameters, such as grain size. Since mechanical properties are dynamic, a more direct approach is to use measurements of defect dynamics coupled with quantitative models to predict mechanical properties. One such measurement is the ultrasonic internal friction as determined by resonance techniques. However, such techniques have limited applicability for testing structural materials, because the techniques require specimens to have free boundaries and, generally, regular geometry. In recent years, diffuse field ultrasound has been used to measure internal friction and shows promise for practical nondestructive materials characterization of irregularly shaped specimens. In this paper, the connection between the resonance and diffuse field techniques will be explored. In addition, measurements performed using these techniques will be compared to traditional pulse echo measurements of attenuation and back scattered grain noise to study the relative contributions of internal friction and scattering in copper and aluminum alloys.—This research was conducted while P. D. Panetta held a National Research Council Research Associateship.

  10. Pulsed remote field eddy current technique applied to non-magnetic flat conductive plates

    NASA Astrophysics Data System (ADS)

    Yang, Binfeng; Zhang, Hui; Zhang, Chao; Zhang, Zhanbin

    2013-12-01

    Non-magnetic metal plates are widely used in aviation and industrial applications. The detection of cracks in thick plate structures, such as multilayered structures of aircraft fuselage, has been challenging in nondestructive evaluation societies. The remote field eddy current (RFEC) technique has shown advantages of deep penetration and high sensitivity to deeply buried anomalies. However, the RFEC technique is mainly used to evaluate ferromagnetic tubes. There are many problems that should be fixed before the expansion and application of this technique for the inspection of non-magnetic conductive plates. In this article, the pulsed remote field eddy current (PRFEC) technique for the detection of defects in non-magnetic conducting plates was investigated. First, the principle of the PRFEC technique was analysed, followed by the analysis of the differences between the detection of defects in ferromagnetic and non-magnetic plain structures. Three different models of the PRFEC probe were simulated using ANSYS. The location of the transition zone, defect detection sensitivity and the ability to detect defects in thick plates using three probes were analysed and compared. The simulation results showed that the probe with a ferrite core had the highest detecting ability. The conclusions derived from the simulation study were also validated by conducting experiments.

  11. Magnetic Field Tunable Small-scale Mechanical Properties of Nickel Single Crystals Measured by Nanoindentation Technique

    PubMed Central

    Zhou, Hao; Pei, Yongmao; Fang, Daining

    2014-01-01

    Nano- and micromagnetic materials have been extensively employed in micro-functional devices. However, measuring small-scale mechanical and magnetomechanical properties is challenging, which restricts the design of new products and the performance of smart devices. A new magnetomechanical nanoindentation technique is developed and tested on a nickel single crystal in the absence and presence of a saturated magnetic field. Small-scale parameters such as Young's modulus, indentation hardness, and plastic index are dependent on the applied magnetic field, which differ greatly from their macroscale counterparts. Possible mechanisms that induced 31% increase in modulus and 7% reduction in hardness (i.e., the flexomagnetic effect and the interaction between dislocations and magnetic field, respectively) are analyzed and discussed. Results could be useful in the microminiaturization of applications, such as tunable mechanical resonators and magnetic field sensors. PMID:24695002

  12. Measurements of solar magnetic fields by Fourier transform techniques. II - Saturated and blended lines

    NASA Technical Reports Server (NTRS)

    Tarbell, T. D.; Title, A. M.

    1976-01-01

    Fourier techniques have been exhaustively calibrated using Unno's (1956) results for the absorption profile of a simple Zeeman triplet. If a simple transformation is applied to the normalized line depths, then magnetic-field strengths and inclination angles can be measured very accurately from noisy saturated line profiles. Systematic errors caused by saturation effects can be estimated and reduced by varying one parameter. When a significant fraction of the line profile is unsplit and unpolarized, large errors may be made in measurements of low fields, unless the line is sufficiently weak. For a weak line, a vertical field of 1600 gauss can be measured to 10% accuracy even when 70% of the line profile is stray light. These stray-light errors are troublesome in measuring fields of gaps and pores but not sunspots. Numerical results of the error analysis are presented graphically.

  13. Visualization of a smoke flow field by using a lidar and DIC technique

    NASA Astrophysics Data System (ADS)

    Park, Nak Gyu; Baik, Sung Hoon; Park, Seung Kyu; Kim, Dong Lyul

    2015-11-01

    A visualization technique for the velocity field of plant smoke is described. We intend to present a long-range measurement method for a velocity field calculation from a series of images containing an illuminated planar layer of fluid. The main system is configured with two technical parts. One is a lidar system, which is for measuring the distance from an observer to the plant smoke, and the other is a DIC (digital image correlation) system. We configured the lidar system by using a Nd-YAG pulsed laser (10 Hz, injection seeded), a telescope (Schmidt Cassegrain type, diameter: 30 cm) and a PMT (photomultiplier tube). The DIC system is configured to track smoke images by using the developed fast correlation algorithm of the DIC. We acquired the velocity fields of smoke by using the calculated distance and the DIC algorithm. In this paper, we propose a new method for measuring the smoke velocity and visualizing the flow field.

  14. Research and implementation of visualization techniques for 3D explosion fields

    NASA Astrophysics Data System (ADS)

    Ning, Jianguo; Xu, Xiangzhao; Ma, Tianbao; Yu, Wen

    2015-12-01

    The visualization of scalar data in 3D explosion fields was devised to solve the problems of the complex physical and the huge data in numerical simulation of explosion mechanics problems. For enhancing the explosion effects and reducing the impacts of image analysis, the adjustment coefficient was added into original Phong illumination model. A variety of accelerated volume rendering algorithm and multithread technique were used to realize the fast rendering and real-time interactive control of 3D explosion fields. Cutaway view was implemented, so arbitrary section of 3D explosion fields can be seen conveniently. Slice can be extracted along three axes of 3D explosion fields, and the value at an arbitrary point on the slice can be gained. The experiment results show that the volume rendering acceleration algorithm can generate high quality images and can increase the speed of image generating, while achieve interactive control quickly.

  15. Investigation of the pressure and velocity fields in a turbulent separated flow using the LES technique

    NASA Astrophysics Data System (ADS)

    Arnal, M.; Friedrich, R.

    1991-01-01

    The large eddy simulation (LES) technique is utilized to investigate the turbulent separating and reattaching flow over a rearward-facing step. Simulations on a series of successively refined grids were performed (maximum resolution: 320 x 64 x 48). Statistical results are compared with experimental data and show good agreement. An examination of the simulated flow fields reveals the instantaneous structure of the separating shear layer, the reattachment zone and the recirculation region. Large departures from the mean in both the velocity and pressure fields are found to occur in all three regions. The shape and size of structures in the velocity and pressure fields varies with the proximity of solid walls and the region of the flow domain. Awareness of the instantaneous flow field structure is shown to be instrumental to having a complete understanding of the unsteady turbulent flow.

  16. The sliding stop: a technique of fielding in cricket with a potential for serious knee injury.

    PubMed

    Von Hagen, K; Roach, R; Summers, B

    2000-10-01

    The sliding stop method of fielding in cricket is gaining popularity in schools and club cricket through its frequent exposure on television. The case history is reported of a cricketer who suffered a torn medial meniscus in his knee, a rare cricketing injury, while performing this technique incorrectly in a club game. The correct method of performing the technique is described in coaching manuals but is not commonly instructed at club or school level. The sliding stop should be discouraged in school and for club cricketers unless appropriately coached. PMID:11049149

  17. 2D Electric field imagery in 4H-SiC power diodes using OBIC technique

    NASA Astrophysics Data System (ADS)

    Hamad, Hassan; Bevilacqua, Pascal; Planson, Dominique; Raynaud, Christophe; Tournier, Dominique; Vergne, Bertrand; Lazar, Mihai; Brosselard, Pierre

    2015-11-01

    Wide band gap semiconductors are more and more used, especially to design high voltage devices. However, some devices show lower breakdown voltages than those predicted in theory. These early breakdown are in general due to imperfections in the peripheral protections of the active junction. The aim of these protections is to reduce electric field peaks at the periphery of the junction. Thus, it is important to study the electric field distribution on the device periphery to detect any protection weakness. This paper presents a 2D electric field imagery using OBIC (optical beam induced current) technique. 2D cartographies are realized on JTE (junction termination extension) protected diodes in order to display electric field on diode peripheries. Other measurements are also performed on circular avalanche diodes protected with a MESA etching and provided with optical window. In both cases, OBIC techniques is demonstrated to be an efficient method to obtain electric field distribution within the device and to locate defects. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014)", edited by Adel Razek

  18. Effect of training characteristics on object classification: An application using Boosted Decision Trees

    NASA Astrophysics Data System (ADS)

    Sevilla-Noarbe, I.; Etayo-Sotos, P.

    2015-06-01

    We present an application of a particular machine-learning method (Boosted Decision Trees, BDTs using AdaBoost) to separate stars and galaxies in photometric images using their catalog characteristics. BDTs are a well established machine learning technique used for classification purposes. They have been widely used specially in the field of particle and astroparticle physics, and we use them here in an optical astronomy application. This algorithm is able to improve from simple thresholding cuts on standard separation variables that may be affected by local effects such as blending, badly calculated background levels or which do not include information in other bands. The improvements are shown using the Sloan Digital Sky Survey Data Release 9, with respect to the type photometric classifier. We obtain an improvement in the impurity of the galaxy sample of a factor 2-4 for this particular dataset, adjusting for the same efficiency of the selection. Another main goal of this study is to verify the effects that different input vectors and training sets have on the classification performance, the results being of wider use to other machine learning techniques.

  19. A technique for measuring magnetic fields on solar-type stars

    NASA Technical Reports Server (NTRS)

    Marcy, G. W.

    1982-01-01

    A method is developed and tested by which magnetic-field strengths and area filling-factors of magnetic regions on late-type stars may be inferred from high-resolution, absorption-line profiles that have been broadened by the Zeeman effect. The technique involves fitting such profiles with a triplet of components, the shape of which is derived from profiles of lines of low Zeeman sensitivity. Tests of the systematic and random errors indicate that such magnetic flux measurements have an uncertainty of 20% for stars with field strengths of 2000 gauss if at least 10% of the stellar surface contains magnetic regions.

  20. Imaging Analysis of Near-Field Recording Technique for Observation of Biological Specimens

    NASA Astrophysics Data System (ADS)

    Moriguchi, Chihiro; Ohta, Akihiro; Egami, Chikara; Kawata, Yoshimasa; Terakawa, Susumu; Tsuchimori, Masaaki; Watanabe, Osamu

    2006-07-01

    We present an analysis of the properties of an imaging based on a near-field recording technique in comparison with simulation results. In the system, the optical field distributions localized near the specimens are recorded as the surface topographic distributions of a photosensitive film. It is possible to observe both soft and moving specimens, because the system does not require a scanning probe to obtain the observed image. The imaging properties are evaluated using fine structures of paramecium, and we demonstrate that it is possible to observe minute differences of refractive indices.

  1. A three-field monoisocentric inverse breast treatment planning technique without half-beam blocking.

    PubMed

    Zhang, Tiezhi; Dilworth, Joshua T; Marina, Ovidiu; Chen, Peter; Benedetti, Lisa; Liu, Qiang

    2015-01-01

    The purpose of this study was to introduce a three-field monoisocentric inverse treatment planning method without half-beam blocks for breast cancer radiation treatments. Three-field monoisocentric breast treatment planning with half-beam blocks limits the tangential field length to 20 cm. A dual-isocenter approach accommodates patients with larger breasts, but prolongs treatment time and may introduce dose uncertainty at the matching plane due to daily setup variations. We developed a novel monoisocentric, three-field treatment planning method without half-beam blocking. The new beam-matching method utilizes the full field size with a single isocenter. Furthermore, an open/IMRT hybrid inverse optimization method was employed to improve dose uniformity and coverage. Geometric beam matching was achieved by rotating the couch, collimator, and gantry together. Formulae for three-field geometric matching were derived and implemented in Pinnacle scripts. This monoisocentric technique can be used for patients with larger breast size. The new method has no constraints on the length of tangential fields. Compared with the dual-isocenter method, it can significantly reduce patient setup time anduncertainties. PMID:26699305

  2. In-field assessment of chemical high explosives using immunoassay techniques

    SciTech Connect

    Hardy, D.J.; Crossley, D.B.; O`Connell, M.S.

    1995-12-31

    Base realignment and weapons complex reconfiguration have prompted closure of former military related properties. As a result, chemical high explosives in environmental media are encountered with greater frequency during accelerated site characterization activities. The DOE`s Pantex nuclear weapons production/disassembly facility in Amarillo, Texas has observed nitroaromatic and nitramine compounds in soil and groundwater. Recognizing that phases characterization programs are time consuming and expensive, Pantex has employed compound specific immunoassay screening techniques to semi-quantitatively assess high explosive contamination in environmental media. As a result of using immunoassay techniques at over 500 sample locations, Pantex has achieved significant benefits corollary to reduced analytical expenses and timeframes, waste generation and management expenditures, field mobilization, and site characterization timeframes. Pantex Plant concludes that the use of immunoassay field screening of samples for chemical high explosives results in accelerated site characterization at a decreased expense while maintaining quality protocols and worker protection.

  3. The Wide-Field Imaging Interferometry Testbed: Enabling Techniques for High Angular Resolution Astronomy

    NASA Technical Reports Server (NTRS)

    Rinehart, S. A.; Armstrong, T.; Frey, Bradley J.; Jung, J.; Kirk, J.; Leisawitz, David T.; Leviton, Douglas B.; Lyon, R.; Maher, Stephen; Martino, Anthony J.; Pauls, T.

    2007-01-01

    The Wide-Field Imaging Interferometry Testbed (WIIT) was designed to develop techniques for wide-field of view imaging interferometry, using "double-Fourier" methods. These techniques will be important for a wide range of future spacebased interferometry missions. We have provided simple demonstrations of the methodology already, and continuing development of the testbed will lead to higher data rates, improved data quality, and refined algorithms for image reconstruction. At present, the testbed effort includes five lines of development; automation of the testbed, operation in an improved environment, acquisition of large high-quality datasets, development of image reconstruction algorithms, and analytical modeling of the testbed. We discuss the progress made towards the first four of these goals; the analytical modeling is discussed in a separate paper within this conference.

  4. Field transients of coherent terahertz synchrotron radiation accessed via time-resolving and correlation techniques

    NASA Astrophysics Data System (ADS)

    Pohl, A.; Semenov, A.; Hübers, H.-W.; Hoehl, A.; Ries, M.; Wüstefeld, G.; Ulm, G.; Ilin, K.; Thoma, P.; Siegel, M.

    2016-03-01

    Decaying oscillations of the electric field in repetitive pulses of coherent synchrotron radiation in the terahertz frequency range was evaluated by means of time-resolving and correlation techniques. Comparative analysis of real-time voltage transients of the electrical response and interferograms, which were obtained with an ultrafast zero-bias Schottky diode detector and a Martin-Puplett interferometer, delivers close values of the pulse duration. Consistent results were obtained via the correlation technique with a pair of Golay Cell detectors and a pair of resonant polarisation-sensitive superconducting detectors integrated on one chip. The duration of terahertz synchrotron pulses does not closely correlate with the duration of single-cycle electric field expected for the varying size of electron bunches. We largely attribute the difference to the charge density oscillations in electron bunches and to the low-frequency spectral cut-off imposed by both the synchrotron beamline and the coupling optics of our detectors.

  5. Application of the Coupled Finite Element-Combined Field Integral Equation Technique (FEICFIE) to the Radiation Problem

    NASA Technical Reports Server (NTRS)

    Jamnejad, V.; Cwik, T.; Zuffada, C.

    1994-01-01

    A coupled finite element-combined field integral equation technique was originally developed for solving scattering problems involving inhomogeneous objects of arbitrary shape and large dimensions in wavelength.

  6. Diagnostic techniques for measurement of aerodynamic noise in free field and reverberant environment of wind tunnels

    NASA Technical Reports Server (NTRS)

    El-Sum, H. M. A.; Mawardi, O. K.

    1973-01-01

    Techniques for studying aerodynamic noise generating mechanisms without disturbing the flow in a free field, and in the reverberation environment of the ARC wind tunnel were investigated along with the design and testing of an acoustic antenna with an electronic steering control. The acoustic characteristics of turbojet as a noise source, detection of direct sound from a source in a reverberant background, optical diagnostic methods, and the design characteristics of a high directivity acoustic antenna. Recommendations for further studies are included.

  7. New dimension in the schlieren technique: flow field analysis using color.

    PubMed

    Maddox, A R; Binder, R C

    1971-03-01

    The various techniques for introducing color into a schlieren system were explored, and all of them were found to have drawbacks such that the added dimension of color in a schlieren has never been utilized for extensive quantitative measurements. An entirely new technique using a diffraction grating to produce the color has been introduced as a modification of the conventional schlieren system. It provides solutions to the problems of sensitivity, range of measurement deflection and undesirable effects of diffraction which have limited the usefulness of color systems in the past. Methods for analyzing a conventional schlieren have been modified for the analysis of a color schlieren result. Surface pressures and flow field analysis for some simple two-dimensional airfoil shapes have been obtained by these color techniques developed here, and the results compare very well with theoretical pressure calculations. PMID:20094475

  8. Full-field detection of surface defects using real-time holography and optical correlation techniques

    NASA Astrophysics Data System (ADS)

    Blackshire, James L.; Duncan, Bradley D.

    1999-02-01

    Innovative optical NDE techniques are being developed for the full-field detection and evaluation of surface defects and defect precursors in titanium and aluminum based alloys. The techniques are based on frequency-translated holography and optical correlation principles, and use bacteriohodopsin (bR) holographic films and temporal correlation techniques for real-time storage and retrieval of Surface Acoustic Waves (SAW) features and embedded surface defect information. The SAW waves induced on the material surface being studied are made to interfere with optical light waves, and fringes are produced that are a function of optical Doppler shifts induced by phonon-photon interaction on the surface of the materials. Visualization of these SAW patterns allow for NDE characterization of features on and near the surface of the materials, including defect and defect precursor sites. Preliminary results are provided for real-time bR holographic recordings of acoustic patterns induced on Al2024-T3 material surfaces.

  9. Comparison of soft computing techniques for a three-phase oil field centrifuge.

    SciTech Connect

    Smith, R. E.; Parkinson, w; Miller, N.

    2002-01-01

    In this work we compare fuzzy techniques to neural network techniques for building a soft sensor for a three-phase oil field centrifuge. The soft sensor is used in a feed-forward control system that augments a feedback control system. Two approaches were used to develop the soft sensor. The first approach was to use a fuzzy rule based system based upon the experience of an expert operator. The expert operator's experience was supplemented using a computer model of the system. The second approach was to use a neural network to build the inverse of the computer model. The pros and cons of both techniques are discussed. KEYWORDS: fuzzy logic, neural networks, soft sensor, soft computing

  10. Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients.

    PubMed

    Penoncello, Gregory P; Ding, George X

    2016-01-01

    The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2cm(3) for head and neck plans and brain plans and a contiguous volume of 5cm(3) for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens. PMID:26764180

  11. An improved DPSM technique for modelling ultrasonic fields in cracked solids

    NASA Astrophysics Data System (ADS)

    Banerjee, Sourav; Kundu, Tribikram; Placko, Dominique

    2007-04-01

    In recent years Distributed Point Source Method (DPSM) is being used for modelling various ultrasonic, electrostatic and electromagnetic field modelling problems. In conventional DPSM several point sources are placed near the transducer face, interface and anomaly boundaries. The ultrasonic or the electromagnetic field at any point is computed by superimposing the contributions of different layers of point sources strategically placed. The conventional DPSM modelling technique is modified in this paper so that the contributions of the point sources in the shadow region can be removed from the calculations. For this purpose the conventional point sources that radiate in all directions are replaced by Controlled Space Radiation (CSR) sources. CSR sources can take care of the shadow region problem to some extent. Complete removal of the shadow region problem can be achieved by introducing artificial interfaces. Numerically synthesized fields obtained by the conventional DPSM technique that does not give any special consideration to the point sources in the shadow region and the proposed modified technique that nullifies the contributions of the point sources in the shadow region are compared. One application of this research can be found in the improved modelling of the real time ultrasonic non-destructive evaluation experiments.

  12. Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds

    PubMed Central

    Medrano, Jose A.; de Nooijer, Niek C. A.; Gallucci, Fausto; van Sint Annaland, Martin

    2016-01-01

    For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO2 as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics. PMID:26927127

  13. From superresolution to nanodetection: overview of far field optical nanoscopy techniques for nanostructures

    NASA Astrophysics Data System (ADS)

    Montgomery, P. C.; Leong-Hoi, A.; Anstotz, F.; Mitev, D.; Pramatarova, L.; Haeberlé, O.

    2016-02-01

    Far field optical nanoscopy has been brought to the forefront with the 2014 Nobel Prize for chemistry in fluorescent nanoscopy for revealing intra-cellular details of tens of nm. In this review, we present an improved classification scheme that summarizes the many optical nanoscopy techniques that exist. We place particular emphasis on unlabelledsuperresolution techniques that provide real improved resolving power and unlabellednanodetection techniques for characterizing unresolved nanostructures. Superresolution is illustrated with sub-100 nm imaging of diatoms with tomographic diffractive microscopyand adenoviruseswith submerged microsphere optical nanoscopy. Three sub-categories of nanodetectionare then presented. Contrast enhancement is illustrated with surface enhanced ellipsometric contrast microscopy for the study of bacterial motility and strobed phase contrast microscopy for measuring the mechanical properties of vesicle membranes. High sensitivity phase measurement using interference microscopy demonstrates how nanostructured surfaces and structures can be characterized in biomaterials, laser textured stainless steel and defects within thin polymer films. Finally, deconvolution is illustrated with the use of through-focus scanning optical microscopy in critical dimension measurement and characterization of 40 nm linewidths in microelectronic devices. In this way we show how new far field optical nanoscopy techniques are being developed for unlabelled characterization of nano and biomaterials.

  14. Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds.

    PubMed

    Medrano, Jose A; de Nooijer, Niek C A; Gallucci, Fausto; van Sint Annaland, Martin

    2016-01-01

    For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO₂ as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics. PMID:26927127

  15. Electric rockets get a boost

    SciTech Connect

    Ashley, S.

    1995-12-01

    This article reports that xenon-ion thrusters are expected to replace conventional chemical rockets in many nonlaunch propulsion tasks, such as controlling satellite orbits and sending space probes on long exploratory missions. The space age dawned some four decades ago with the arrival of powerful chemical rockets that could propel vehicles fast enough to escape the grasp of earth`s gravity. Today, chemical rocket engines still provide the only means to boost payloads into orbit and beyond. The less glamorous but equally important job of moving vessels around in space, however, may soon be assumed by a fundamentally different rocket engine technology that has been long in development--electric propulsion.

  16. Towards a sterile insect technique field release of Anopheles arabiensis mosquitoes in Sudan: Irradiation, transportation, and field cage experimentation

    PubMed Central

    Helinski, Michelle EH; Hassan, Mo'awia M; El-Motasim, Waleed M; Malcolm, Colin A; Knols, Bart GJ; El-Sayed, Badria

    2008-01-01

    Background The work described in this article forms part of a study to suppress a population of the malaria vector Anopheles arabiensis in Northern State, Sudan, with the Sterile Insect Technique. No data have previously been collected on the irradiation and transportation of anopheline mosquitoes in Africa, and the first series of attempts to do this in Sudan are reported here. In addition, experiments in a large field cage under near-natural conditions are described. Methods Mosquitoes were irradiated in Khartoum and transported as adults by air to the field site earmarked for future releases (400 km from the laboratory). The field cage was prepared for experiments by creating resting sites with favourable conditions. The mating and survival of (irradiated) laboratory males and field-collected males was studied in the field cage, and two small-scale competition experiments were performed. Results Minor problems were experienced with the irradiation of insects, mostly associated with the absence of a rearing facility in close proximity to the irradiation source. The small-scale transportation of adult mosquitoes to the release site resulted in minimal mortality (< 6%). Experiments in the field cage showed that mating occurred in high frequencies (i.e. an average of 60% insemination of females after one or two nights of mating), and laboratory reared males (i.e. sixty generations) were able to inseminate wild females at rates comparable to wild males. Based on wing length data, there was no size preference of males for mates. Survival of mosquitoes from the cage, based on recapture after mating, was satisfactory and approximately 60% of the insects were recaptured after one night. Only limited information on male competitiveness was obtained due to problems associated with individual egg laying of small numbers of wild females. Conclusion It is concluded that although conditions are challenging, there are no major obstacles associated with the small

  17. Recursive bias estimation and L2 boosting

    SciTech Connect

    Hengartner, Nicolas W; Cornillon, Pierre - Andre; Matzner - Lober, Eric

    2009-01-01

    This paper presents a general iterative bias correction procedure for regression smoothers. This bias reduction schema is shown to correspond operationally to the L{sub 2} Boosting algorithm and provides a new statistical interpretation for L{sub 2} Boosting. We analyze the behavior of the Boosting algorithm applied to common smoothers S which we show depend on the spectrum of I - S. We present examples of common smoother for which Boosting generates a divergent sequence. The statistical interpretation suggest combining algorithm with an appropriate stopping rule for the iterative procedure. Finally we illustrate the practical finite sample performances of the iterative smoother via a simulation study.

  18. Initial field studies in Upper Volta with dichlorvos residual fumigant as a malaria eradication technique*

    PubMed Central

    Quarterman, K. D.; Lotte, M.; Schoof, H. F.

    1963-01-01

    Laboratory and simulated field tests have shown that dichlorvos, a volatile insecticide, can be prepared in a solid formulation which releases the dichlorvos vapour over a period of several months at a relatively uniform rate high enough to kill adult anopheline mosquitos but low enough to have no effect on man and the higher animals. A field experiment is in progress in Wakara, Upper Volta, to evaluate the residual fumigant technique under practical field conditions. Chemical, biological, toxicological and epidemiological data obtained during the first nine months indicate that the method produced dichlorvos vapours in a concentration effective against mosquitos for 3 to 5 months per treatment, that the occupants of the treated dwellings showed no detectable effects from the insecticidal vapours, and that the malaria rates were reduced by 38%-55% among the population of the treated village as compared with a nearby untreated control village. ImagesFIG. 1FIG. 2 PMID:14056276

  19. The derivation of vector magnetic fields from Stokes profiles - Integral versus least squares fitting techniques

    NASA Technical Reports Server (NTRS)

    Ronan, R. S.; Mickey, D. L.; Orrall, F. Q.

    1987-01-01

    The results of two methods for deriving photospheric vector magnetic fields from the Zeeman effect, as observed in the Fe I line at 6302.5 A at high spectral resolution (45 mA), are compared. The first method does not take magnetooptical effects into account, but determines the vector magnetic field from the integral properties of the Stokes profiles. The second method is an iterative least-squares fitting technique which fits the observed Stokes profiles to the profiles predicted by the Unno-Rachkovsky solution to the radiative transfer equation. For sunspot fields above about 1500 gauss, the two methods are found to agree in derived azimuthal and inclination angles to within about + or - 20 deg.

  20. Proposal of Boost Motor Driver with Electric Double Layer Capacitor

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hirokazu

    This paper proposes a boost motor driver with EDLC as a new boost motor driver. The boost motor driver has two advantages against conventional boost motor drivers. The first is that the boost motor driver can decrease an input power peak. The second is that the boost motor driver can charge almost all regeneration energy. The dynamic performance of boost voltage and these advantages of the boost motor driver is simulated. From the simulation, results that the boost motor driver has good performance are derived.

  1. Visualizing the blind brain: brain imaging of visual field defects from early recovery to rehabilitation techniques

    PubMed Central

    Urbanski, Marika; Coubard, Olivier A.; Bourlon, Clémence

    2014-01-01

    Visual field defects (VFDs) are one of the most common consequences observed after brain injury, especially after a stroke in the posterior cerebral artery territory. Less frequently, tumors, traumatic brain injury, brain surgery or demyelination can also determine various visual disabilities, from a decrease in visual acuity to cerebral blindness. Visual field defects is a factor of bad functional prognosis as it compromises many daily life activities (e.g., obstacle avoidance, driving, and reading) and therefore the patient’s quality of life. Spontaneous recovery seems to be limited and restricted to the first 6 months, with the best chance of improvement at 1 month. The possible mechanisms at work could be partly due to cortical reorganization in the visual areas (plasticity) and/or partly to the use of intact alternative visual routes, first identified in animal studies and possibly underlying the phenomenon of blindsight. Despite processes of early recovery, which is rarely complete, and learning of compensatory strategies, the patient’s autonomy may still be compromised at more chronic stages. Therefore, various rehabilitation therapies based on neuroanatomical knowledge have been developed to improve VFDs. These use eye-movement training techniques (e.g., visual search, saccadic eye movements), reading training, visual field restitution (the Vision Restoration Therapy, VRT), or perceptual learning. In this review, we will focus on studies of human adults with acquired VFDs, which have used different imaging techniques (Positron Emission Tomography, PET; Diffusion Tensor Imaging, DTI; functional Magnetic Resonance Imaging, fMRI; Magneto Encephalography, MEG) or neurostimulation techniques (Transcranial Magnetic Stimulation, TMS; transcranial Direct Current Stimulation, tDCS) to show brain activations in the course of spontaneous recovery or after specific rehabilitation techniques. PMID:25324739

  2. Singular Stokes-polarimetry as new technique for metrology and inspection of polarized speckle fields

    NASA Astrophysics Data System (ADS)

    Soskin, Marat S.; Denisenko, Vladimir G.; Egorov, Roman I.

    2004-08-01

    Polarimetry is effective technique for polarized light fields characterization. It was shown recently that most full "finger-print" of light fields with arbitrary complexity is network of polarization singularities: C points with circular polarization and L lines with variable azimuth. The new singular Stokes-polarimetry was elaborated for such measurements. It allows define azimuth, eccentricity and handedness of elliptical vibrations in each pixel of receiving CCD camera in the range of mega-pixels. It is based on precise measurement of full set of Stokes parameters by the help of high quality analyzers and quarter-wave plates with λ/500 preciseness and 4" adjustment. The matrices of obtained data are processed in PC by special programs to find positions of polarization singularities and other needed topological features. The developed SSP technique was proved successfully by measurements of topology of polarized speckle-fields produced by multimode "photonic-crystal" fibers, double side rubbed polymer films, biomedical samples. Each singularity is localized with preciseness up to +/- 1 pixel in comparison with 500 pixels dimensions of typical speckle. It was confirmed that network of topological features appeared in polarized light field after its interaction with specimen under inspection is exact individual "passport" for its characterization. Therefore, SSP can be used for smart materials characterization. The presented data show that SSP technique is promising for local analysis of properties and defects of thin films, liquid crystal cells, optical elements, biological samples, etc. It is able discover heterogeneities and defects, which define essentially merits of specimens under inspection and can"t be checked by usual polarimetry methods. The detected extra high sensitivity of polarization singularities position and network to any changes of samples position and deformation opens quite new possibilities for sensing of deformations and displacement of

  3. New techniques for the scientific visualization of three-dimensional multi-variate and vector fields

    SciTech Connect

    Crawfis, R.A.

    1995-10-01

    Volume rendering allows us to represent a density cloud with ideal properties (single scattering, no self-shadowing, etc.). Scientific visualization utilizes this technique by mapping an abstract variable or property in a computer simulation to a synthetic density cloud. This thesis extends volume rendering from its limitation of isotropic density clouds to anisotropic and/or noisy density clouds. Design aspects of these techniques are discussed that aid in the comprehension of scientific information. Anisotropic volume rendering is used to represent vector based quantities in scientific visualization. Velocity and vorticity in a fluid flow, electric and magnetic waves in an electromagnetic simulation, and blood flow within the body are examples of vector based information within a computer simulation or gathered from instrumentation. Understand these fields can be crucial to understanding the overall physics or physiology. Three techniques for representing three-dimensional vector fields are presented: Line Bundles, Textured Splats and Hair Splats. These techniques are aimed at providing a high-level (qualitative) overview of the flows, offering the user a substantial amount of information with a single image or animation. Non-homogenous volume rendering is used to represent multiple variables. Computer simulations can typically have over thirty variables, which describe properties whose understanding are useful to the scientist. Trying to understand each of these separately can be time consuming. Trying to understand any cause and effect relationships between different variables can be impossible. NoiseSplats is introduced to represent two or more properties in a single volume rendering of the data. This technique is also aimed at providing a qualitative overview of the flows.

  4. Field Manual of Techniques in Invertebrate Pathology: Application and Evaluation of Pathogens for Control of Insects and Other Invertebrate Pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Field Manual of Techniques in Invertebrate Pathology is designed to provide background and instruction on a broad spectrum of techniques and their use in the evaluation of entomopathogens in the field. The intended audience includes researchers, graduate students, practitioners of integrated pes...

  5. The gradient boosting algorithm and random boosting for genome-assisted evaluation in large data sets.

    PubMed

    González-Recio, O; Jiménez-Montero, J A; Alenda, R

    2013-01-01

    In the next few years, with the advent of high-density single nucleotide polymorphism (SNP) arrays and genome sequencing, genomic evaluation methods will need to deal with a large number of genetic variants and an increasing sample size. The boosting algorithm is a machine-learning technique that may alleviate the drawbacks of dealing with such large data sets. This algorithm combines different predictors in a sequential manner with some shrinkage on them; each predictor is applied consecutively to the residuals from the committee formed by the previous ones to form a final prediction based on a subset of covariates. Here, a detailed description is provided and examples using a toy data set are included. A modification of the algorithm called "random boosting" was proposed to increase predictive ability and decrease computation time of genome-assisted evaluation in large data sets. Random boosting uses a random selection of markers to add a subsequent weak learner to the predictive model. These modifications were applied to a real data set composed of 1,797 bulls genotyped for 39,714 SNP. Deregressed proofs of 4 yield traits and 1 type trait from January 2009 routine evaluations were used as dependent variables. A 2-fold cross-validation scenario was implemented. Sires born before 2005 were used as a training sample (1,576 and 1,562 for production and type traits, respectively), whereas younger sires were used as a testing sample to evaluate predictive ability of the algorithm on yet-to-be-observed phenotypes. Comparison with the original algorithm was provided. The predictive ability of the algorithm was measured as Pearson correlations between observed and predicted responses. Further, estimated bias was computed as the average difference between observed and predicted phenotypes. The results showed that the modification of the original boosting algorithm could be run in 1% of the time used with the original algorithm and with negligible differences in accuracy

  6. Computerized tomography technique for reconstruction of obstructed temperature field in infrared thermography

    NASA Astrophysics Data System (ADS)

    Sham, F. C.; Huang, Y. H.; Liu, L.; Chen, Y. S.; Hung, Y. Y.; Lo, T. Y.

    2010-01-01

    Infrared thermography is a rapid, non-invasive and full-field technique for non-destructive testing and evaluation (NDT&E). With all the achievements on IR instrumentation and image processing techniques attained, it has been extended far beyond simple hot-spot detection and becomes one of the most promising NDT&E techniques in the last decades. It has achieved increasing acceptance in different sectors include medical imaging, manufacturing component fault detection and buildings diagnostic. However, one limitation of IR thermography is that the testing results are greatly affected by object surface emissivity. Surface with various emissivities may lead to difficult discrimination between area of defect and area with different emissivity. Therefore, many studies have been carried out on eliminating emissivity, for example, the time derivative approach, lock-in processing and differential contrast measurements. In these methods, sequence of themo-data/images are recorded and being processed in order to eliminate differences of emissivity. Another problem of IR thermography is that any obstruction may limit stimulations and imaging which leads to the observation of unclear defect image. To solve this problem, this paper proposes an algorithm based on the principle of computerized tomography which permits the reconstruction of unavailable/partially available temperature distribution of the affected area using the measured surrounding temperature field. In the process, a set of imaginary rays are projected from many different directions across the area. For each ray, integration of the temperature derivatives along the ray is equals to the temperature difference between the boundary points intercepted by the ray. Therefore, a set of linear equations can be established by considering the multiple rays. Each equation expresses the unknown temperature derivatives in the affected area in terms of the measured boundary temperature data. Solution of the set of simultaneous

  7. Near-field Light Scattering Techniques for Measuring Nanoparticle-Surface Interaction Energies and Forces

    PubMed Central

    O'Dell, Dakota; Adam, Ian S.; DiPaolo, Brian; Sabharwal, Manit; Shi, Ce; Hart, Robert; Earhart, Christopher; Erickson, David

    2015-01-01

    Nanoparticles are quickly becoming commonplace in many commercial and industrial products, ranging from cosmetics to pharmaceuticals to medical diagnostics. Predicting the stability of the engineered nanoparticles within these products a priori remains an important and difficult challenge. Here we describe our techniques for measuring the mechanical interactions between nanoparticles and surfaces using near-field light scattering. Particle-surface interfacial forces are measured by optically “pushing” a particle against a reference surface and observing its motion using scattered near-field light. Unlike atomic force microscopy, this technique is not limited by thermal noise, but instead takes advantage of it. The integrated waveguide and microfluidic architecture allow for high-throughput measurements of about 1000 particles per hour. We characterize the reproducibility of and experimental uncertainty in the measurements made using the NanoTweezer surface instrument. We report surface interaction studies on gold nanoparticles with 50 nm diameters, smaller than previously reported in the literature using similar techniques. PMID:26855473

  8. High Pressure Techniques for Low Temperature Studies in DC and Pulsed Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Tozer, S. W.

    Pressure can be used to expand the parameter space available in almost any experiment and allows for the continuous tuning of the electrical and orbital properties of a material. When combined with low temperatures and high magnetic fields, it becomes a powerful tool for the exploration of the band structure and defect levels in semiconductors, exotic transport mechanisms in molecular conductors, and the coexistence of magnetism and superconductivity. We have developed a variety of miniature pressure cells to allow the user to take full advantage of these opportunities. Metallic diamond anvil cells as small as 6 mm in diameter and 8 mm in height allow the sample to be rotated in field at millikelvin temperatures. Miniature plastic DACs and sapphire ball cells, rotators, and specialized He-4 and He-3 systems have also been developed to provide similar experimental capabilities in pulsed magnetic fields. Methods and designs to generate hydrostatic pressure and techniques to perform optical and electrical measurements in DC and pulsed fields will be presented. We would like to acknowledge the technical assistance of Richard Desilets, Howard Kolb, John Farrell, and Mike Pacheco. A portion of this work was performed at the National High Magnetic Field Laboratory, which is sponsored by NSF Cooperative Agreement No. DMR-9527035 and by the State of Florida.

  9. High Pressure Techniques for Low Temperature Studies in DC and Pulsed Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Tozer, S. W.

    2002-07-01

    Pressure can be used to expand the parameter space available in almost any experiment and allows for the continuous tuning of the electrical and orbital properties of a material. When combined with low temperatures and high magnetic fields, it becomes a powerful tool for the exploration of the band structure and defect levels in semiconductors, exotic transport mechanisms in molecular conductors, and the coexistence of magnetism and superconductivity. We have developed a variety of miniature pressure cells to allow the user to take full advantage of these opportunities. Metallic diamond anvil cells as small as 6 mm in diameter and 8 mm in height allow the sample to be rotated in field at millikelvin temperatures. Miniature plastic DACs and sapphire ball cells, rotators, and specialized He-4 and He-3 systems have also been developed to provide similar experimental capabilities in pulsed magnetic fields. Methods and designs to generate hydrostatic pressure and techniques to perform optical and electrical measurements in DC and pulsed fields will be presented. We would like to acknowledge the technical assistance of Richard Desilets, Howard Kolb, John Farrell, and Mike Pacheco. A portion of this work was performed at the National High Magnetic Field Laboratory, which is sponsored by NSF Cooperative Agreement No. DMR-9527035 and by the State of Florida.

  10. Impact of the Radiation Boost on Outcomes After Breast-Conserving Surgery and Radiation

    SciTech Connect

    Murphy, Colin; Anderson, Penny R.; Li Tianyu; Bleicher, Richard J.; Sigurdson, Elin R.; Goldstein, Lori J.; Swaby, Ramona; Denlinger, Crystal; Dushkin, Holly; Nicolaou, Nicos; Freedman, Gary M.

    2011-09-01

    Purpose: We examined the impact of radiation tumor bed boost parameters in early-stage breast cancer on local control and cosmetic outcomes. Methods and Materials: A total of 3,186 women underwent postlumpectomy whole-breast radiation with a tumor bed boost for Tis to T2 breast cancer from 1970 to 2008. Boost parameters analyzed included size, energy, dose, and technique. Endpoints were local control, cosmesis, and fibrosis. The Kaplan-Meier method was used to estimate actuarial incidence, and a Cox proportional hazard model was used to determine independent predictors of outcomes on multivariate analysis (MVA). The median follow-up was 78 months (range, 1-305 months). Results: The crude cosmetic results were excellent in 54%, good in 41%, and fair/poor in 5% of patients. The 10-year estimate of an excellent cosmesis was 66%. On MVA, independent predictors for excellent cosmesis were use of electron boost, lower electron energy, adjuvant systemic therapy, and whole-breast IMRT. Fibrosis was reported in 8.4% of patients. The actuarial incidence of fibrosis was 11% at 5 years and 17% at 10 years. On MVA, independent predictors of fibrosis were larger cup size and higher boost energy. The 10-year actuarial local failure was 6.3%. There was no significant difference in local control by boost method, cut-out size, dose, or energy. Conclusions: Likelihood of excellent cosmesis or fibrosis are associated with boost technique, electron energy, and cup size. However, because of high local control and rare incidence of fair/poor cosmesis with a boost, the anatomy of the patient and tumor cavity should ultimately determine the necessary boost parameters.

  11. Induction and concurrent chemotherapy with concomitant boost radiotherapy in non-small cell lung cancer.

    PubMed

    Oral, Ethem Nezih; Aydiner, Adnan; Eralp, Yesim; Topuz, Erkan

    2005-01-01

    This study was designed to evaluate the tolerability and therapeutic activity of paclitaxel and carboplatin combination therapy followed by radical thoracic radiotherapy with a concomitant boost technique with concurrent weekly paclitaxel in good performance status of patients with stage IIIA and IIIB non-small cell lung cancer. Patients with newly diagnosed inoperable non-small cell lung cancer received paclitaxel (100 mg/m(2)) as a 1-h infusion on d 1,8,15,28,35, and 42. Carboplatin (area under the curve of 6) was given as a 30-min infusion on d 1 and 28. Radiotherapy commenced on d 49 and was delivered with accelerated fractionation with concomitant boost at 1.8 Gy/fraction/d, 5 d/week and 1.5 Gy/fraction/d to a boost field as a second daily treatment for the last 10 treatment days to 60 Gy/35 fractions/5 wk. During radiation treatment, paclitaxel (60 mg/m(2)) was given as a 1-h infusion once weekly for 5 wk. Twenty-four patients were enrolled in the study. Hematologic toxicities and alopecia were the major acute toxicities during induction chemotherapy; 8.7% of the patients experienced grade 3-4 neutropenia and alopecia. The main acute toxicity of concurrent chemoradiotherapy was esophagitis; grade 3 esophagitis was documented in 23.5% of the patients. No major late toxicity was seen. Overall response rate to the treatment was 65.2%. The median and 1-yr overall-survival rates were 24.9 mo and 63.8%, respectively. The median and 1-yr progression-free survival rates were 9.0 mo and 27.8%, respectively. The main acute toxicities were hematologic toxicity, esophagitis, and alopecia. The response rate and the survival rates achieved with this treatment regimen are particularly noteworthy, especially considering the advanced stage of the patients treated. PMID:16260854

  12. Geophysical gas monitoring using optical techniques: volcanoes, geothermal fields and mines

    NASA Astrophysics Data System (ADS)

    Svanberg, S.

    2002-02-01

    Optical spectroscopy provides powerful means for studying geophysical gas emissions. An extensive research program in this field has been performed by Swedish researchers in collaboration with European partners during the last 10 years, and a review of the activities and results is given. The techniques suitable for geophysical gas monitoring include the differential absorption lidar (DIAL), differential optical absorption spectroscopy (DOAS), diode laser spectroscopy and gas correlation imaging. Field experiments regarding atomic mercury emissions from geothermal fields were performed with a mobile lidar laboratory in Iceland and in Italy. The atomic mercury concentrations and fluxes from mercury mines were also determined at Abbadia S. Salvatore (Italy) and Almadén (Spain). The volcanic emissions of sulfur dioxide were studied in four ship-borne campaigns concerning the three Italian volcanoes Mt. Etna, Stromboli and Vulcano. Comparisons between the results from the DIAL and passive techniques (DOAS and correlation spectroscopy) were performed. Infrared spectroscopy for geophysical applications is now being developed and will also be discussed.

  13. Field panel method with grid stretching technique for solving transonic potential flow around arbitrary airfoils

    NASA Astrophysics Data System (ADS)

    Zhang, H.-L.; Röttgermann, A.; Wagner, S.

    1995-01-01

    The Field Panel Method (FPM) with grid stretching technique, presented in this paper, was developed for solving transonic full potential flow around arbitrary airfoils at incidence. In this method, the total potential values are represented by boundary integrals together with a volume integral. The volume integral domain includes both inside and finite outside of the configuration and can be discretisized in a Cartesian grid which may penetrate into the configuration surface. Thus, we avoid the very difficult task of generating body-fitted grids around complex configurations. The boundary potential values are obtained by implementing a standard panel method (symmetrical singularity model), whereas the field potential values are estimated by solving the full potential equation (using AF3 scheme in a Cartesian grid) with approximate inner and proper outer boundary conditions. Furthermore, the grid stretching technique has been utilized that allows to capture the shock waves in a much better quality. It is also shown that both field grid and panel distribution have to be stretched at the same time. Results for transonic potential flows about NACA0012 and RAE2822 airfoils at different Mach numbers and incidences are obtained and compared with other numerical solutions. Great improvement in shock wave quality was achieved by using the present method.

  14. Investigation of the flow field inside flat-plate collector tube using PIV technique

    SciTech Connect

    Sookdeo, Steven; Siddiqui, Kamran

    2010-06-15

    The thermofluid process inside the tube of flat-plate collectors is complex because the non-uniform heating of the tube results in the formation of stably and unstably stratified layers of fluid that interact with each other. The measurement and investigation of the flow behaviour inside the collector tube is very challenging. We report on a novel application of the particle image velocimetry (PIV) technique to remotely measure the velocity field inside the collector tube. The two-dimensional velocity fields were measured in the midplane of a collector tube for the Reynolds number range of 150-900 at unheated and four different heating conditions. We have presented and discussed in detail the technique implementation and the associated challenges. The results have shown that the collector heating significantly alters the structure and magnitude of the mean velocity field and influences the heat transfer to the fluid. It is observed that the collector heating causes a significant asymmetry in the mean velocity profiles over the given range of Reynolds numbers and heating conditions. (author)

  15. Comparing and Reconciling Traditional Field and Photogeologic Mapping Techniques: Lessons from the San Francisco Volcanic Field, Arizona

    NASA Technical Reports Server (NTRS)

    Skinner, J. A., Jr.; Eppler, D. B.; Bleacher, J. E.; Evans, C. A.; Feng, W.; Gruener, J.; Hurwitz, D. M.; Janoiko, B.; Whitson, P.

    2014-01-01

    Cartographic products and - specifically - geologic maps provide critical assistance for establishing physical and temporal frameworks of planetary surfaces. The technical methods that result in the creation of geologic maps vary depending on how observations are made as well as the overall intent of the final products [1-3]. These methods tend to follow a common linear work flow, including the identification and delineation of spatially and temporally discrete materials (units), the documentation of their primary (emplacement) and secondary (erosional) characteristics, analysis of the relative and absolute age relationships between these materials, and the collation of observations and interpretations into an objective map product. The "objectivity" of a map is critical cross comparison with overlapping maps and topical studies as well as its relevance to scientific posterity. However, the "accuracy" and "correctness" of a geologic map is very subject to debate. This can be evidenced by comparison of existing geologic maps at various scales, particularly those compiled through field- and remote-based mapped efforts. Our study focuses on comparing the fidelity of (1) "Apollo-style" geologic investigations, where typically non-geologist crew members follow static traverse routes established through pre-mission planning, and (2) "traditional" field-based investigations, where geologists are given free rein to observe without preplanned routes. This abstract summarizes the regional geology wherein our study was conducted, presents the geologic map created from traditional field mapping techniques, and offers basic insights into how geologic maps created from different tactics can be reconciled in support of exploratory missions. Additional abstracts [4-6] from this study discuss various exploration and science results of these efforts.

  16. Digital image enhancement techniques used in some ERTS application problems. [geology, geomorphology, and oceanography

    NASA Technical Reports Server (NTRS)

    Goetz, A. F. H.; Billingsley, F. C.

    1974-01-01

    Enhancements discussed include contrast stretching, multiratio color displays, Fourier plane operations to remove striping and boosting MTF response to enhance high spatial frequency content. The use of each technique in a specific application in the fields of geology, geomorphology and oceanography is demonstrated.

  17. Series Connected Buck-Boost Regulator

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur G. (Inventor)

    2006-01-01

    A Series Connected Buck-Boost Regulator (SCBBR) that switches only a fraction of the input power, resulting in relatively high efficiencies. The SCBBR has multiple operating modes including a buck, a boost, and a current limiting mode, so that an output voltage of the SCBBR ranges from below the source voltage to above the source voltage.

  18. 5D parameter estimation of near-field sources using hybrid evolutionary computational techniques.

    PubMed

    Zaman, Fawad; Qureshi, Ijaz Mansoor

    2014-01-01

    Hybrid evolutionary computational technique is developed to jointly estimate the amplitude, frequency, range, and 2D direction of arrival (elevation and azimuth angles) of near-field sources impinging on centrosymmetric cross array. Specifically, genetic algorithm is used as a global optimizer, whereas pattern search and interior point algorithms are employed as rapid local search optimizers. For this, a new multiobjective fitness function is constructed, which is the combination of mean square error and correlation between the normalized desired and estimated vectors. The performance of the proposed hybrid scheme is compared not only with the individual responses of genetic algorithm, interior point algorithm, and pattern search, but also with the existing traditional techniques. The proposed schemes produced fairly good results in terms of estimation accuracy, convergence rate, and robustness against noise. A large number of Monte-Carlo simulations are carried out to test out the validity and reliability of each scheme. PMID:24701156

  19. A multi-software modeling technique for field distribution propagation through an optical vertical interconnect assembly

    NASA Astrophysics Data System (ADS)

    Howard, Matthew D.

    2011-12-01

    Embedded siloxane polymer waveguides have shown promising results for use in optical backplanes. They exhibit high temperature stability, low optical absorption, and require common processing techniques. A challenging aspect of this technology is out-of-plane coupling of the waveguides. A multi-software approach to modeling an optical vertical interconnect (via) is proposed. This approach utilizes the beam propagation method to generate varied modal field distribution structures which are then propagated through a via model using the angular spectrum propagation technique. Simulation results show average losses between 2.5 and 4.5 dB for different initial input conditions. Certain configurations show losses of less than 3 dB and it is shown that in an input/output pair of vias, average losses per via may be lower than the targeted 3 dB.

  20. Detection and Isolation Techniques for Methanogens from Microbial Mats (in the El Tatio Geyser Field, Chile)

    NASA Astrophysics Data System (ADS)

    Pearson, E. Z.; Franks, M. A.; Bennett, P.

    2010-12-01

    Isolating methanogenic archea from an extreme environment such as El Tatio (high altitude, arid climate) gives insight to the methanogenic taxas able to adapt and grow under extreme conditions. The hydrothermal waters at El Tatio geyser field demonstrate extreme geochemical conditions, with discharge water from springs and geysers at local boiling temperature (85° C) with high levels of arsenic and low DIC levels. Despite these challenges, many of El Tatio’s hundred plus hydrothermal features host extensive microbial mat communities, many showing evidence of methanogenesis. When trying to isolate methanogens unique to this area, various approaches and techniques were used. To detect the presence of methanogens in samples taken from the field, dissolved methane concentrations were determined via gas chromatography (GC) analysis. Samples were then selected for culturing and most probable number (MPN) enumeration, where growth was assessed using both methane production and observations of fluorescence under UV light. PCR was used to see if the archeal DNA was apparent directly from the field, and shotgun cloning was done to determine phylogenetic affiliation. Several culturing techniques were carried out in an attempt to isolate methanogens from samples that showed evidence of methanogenesis. The slant culturing method was used because of the increased surface area for colonization combined with the relative ease of keeping anaerobic. After a few weeks, when colonies were apparent, some were aseptically selected and inoculated to observe growth in a liquid media containing ampicillin to inhibit bacterial growth. Culturing techniques proved successful after inoculation, showing a slow growth of methanogens via GC and autofluorescence. Further PCR tests and subsequent sequencing were done to confirm and identify isolates.

  1. On the determination of agricultural prospects using remote sensing and field technique

    NASA Astrophysics Data System (ADS)

    Emetere, Moses Eterigho; Omotosho, T. V.; Olusola, Kayode

    2016-02-01

    The food budget is gradually depleting due to climatic change. The research problem is to see the extent of climate change via catalytic factor e.g. soil compaction. The field work has been reported and the remote sensing technique was used to compliment salient findings established. The Modern Era Retrospective-analysis for Research and Applications (MERRA) was used to obtain five years satellite imagery between 2008 and 2012. The results were used to propound a simple model which shows that the effects of either H >ɛ σ Tr4 or H <ɛ σ Tr4 may be detrimental to crop survival in the nearest future.

  2. A controlled field pilot for testing near surface CO2 detection techniques and transport models

    USGS Publications Warehouse

    Spangler, L.H.; Dobeck, L.M.; Repasky, K.; Nehrir, A.; Humphries, S.; Keith, C.; Shaw, J.; Rouse, J.; Cunningham, A.; Benson, S.; Oldenburg, C.M.; Lewicki, J.L.; Wells, A.; Diehl, R.; Strazisar, B.; Fessenden, J.; Rahn, Thomas; Amonette, J.; Barr, J.; Pickles, W.; Jacobson, J.; Silver, E.; Male, E.; Rauch, H.; Gullickson, K.; Trautz, R.; Kharaka, Y.; Birkholzer, J.; Wielopolski, L.

    2009-01-01

    A field facility has been developed to allow controlled studies of near surface CO2 transport and detection technologies. The key component of the facility is a shallow, slotted horizontal well divided into six zones. The scale and fluxes were designed to address large scale CO2 storage projects and desired retention rates for those projects. A wide variety of detection techniques were deployed by collaborators from 6 national labs, 2 universities, EPRI, and the USGS. Additionally, modeling of CO2 transport and concentrations in the saturated soil and in the vadose zone was conducted. An overview of these results will be presented. ?? 2009 Elsevier Ltd. All rights reserved.

  3. Time-domain incident-field extrapolation technique based on the singularity-expansion method

    SciTech Connect

    Klaasen, J.J.

    1991-05-01

    In this report, a method presented to extrapolate measurements from Nuclear Electromagnetic Pulse (NEMP) assessments directly in the time domain. This method is based on a time-domain extrapolation function which is obtained from the Singularity Expansion Method representation of the measured incident field of the NEMP simulator. Once the time-domain extrapolation function is determined, the responses recorded during an assessment can be extrapolated simply by convolving them with the time domain extrapolation function. It is found that to obtain useful extrapolated responses, the incident field measurements needs to be made minimum phase; otherwise unbounded results can be obtained. Results obtained with this technique are presented, using data from actual assessments.

  4. Boost-phase discrimination research

    NASA Technical Reports Server (NTRS)

    Langhoff, Stephen R.; Feiereisen, William J.

    1993-01-01

    The final report describes the combined work of the Computational Chemistry and Aerothermodynamics branches within the Thermosciences Division at NASA Ames Research Center directed at understanding the signatures of shock-heated air. Considerable progress was made in determining accurate transition probabilities for the important band systems of NO that account for much of the emission in the ultraviolet region. Research carried out under this project showed that in order to reproduce the observed radiation from the bow shock region of missiles in their boost phase it is necessary to include the Burnett terms in the constituent equation, account for the non-Boltzmann energy distribution, correctly model the NO formation and rotational excitation process, and use accurate transition probabilities for the NO band systems. This work resulted in significant improvements in the computer code NEQAIR that models both the radiation and fluid dynamics in the shock region.

  5. Advanced Airfoils Boost Helicopter Performance

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Carson Helicopters Inc. licensed the Langley RC4 series of airfoils in 1993 to develop a replacement main rotor blade for their Sikorsky S-61 helicopters. The company's fleet of S-61 helicopters has been rebuilt to include Langley's patented airfoil design, and the helicopters are now able to carry heavier loads and fly faster and farther, and the main rotor blades have twice the previous service life. In aerial firefighting, the performance-boosting airfoils have helped the U.S. Department of Agriculture's Forest Service control the spread of wildfires. In 2003, Carson Helicopters signed a contract with Ducommun AeroStructures Inc., to manufacture the composite blades for Carson Helicopters to sell

  6. Development and application of color schlieren technique for investigation of three-dimensional concentration field

    NASA Astrophysics Data System (ADS)

    Srivastava, Atul

    2013-11-01

    The present work describes the development and application of rainbow schlieren deflectometry technique for the investigation of the three-dimensional concentration field around a crystal growing from its aqueous solution. The imaging technique employs a diverging beam of light to record the projection data of the concentration field. In contrast to the conventional schlieren methods, the present system makes use of a microscopic objective lens to act as the de-collimating lens for focusing the light beam onto the color filter to get the desired schlieren effect. In order to record the projection data of the concentration field from different view angles for tomographic reconstruction, the experiments are conducted in an octagonal growth cell. Detailed quantitative analysis of the schlieren images has then been carried out for each view angle to determine the path-integrated concentration distribution. Principles of tomography have been employed for the reconstruction of concentration field at select horizontal planes above the growing crystal. Results have been presented in the form of rainbow schlieren images of the convective field, path-averaged solute concentration distribution around the growing for each view angle and local concentration distribution at select horizontal planes above the crystal top surface. Recorded color schlieren images have been compared with those of the conventional monochrome schlieren and interferometric techniques for the same experimental conditions. The extent of color re-distribution as seen from the recorded rainbow schlieren images correlate well with the bright intensity regions of monochrome schlieren images and the extent of fringe deformation in the interferometric images. The comparison has been performed for a small as well as a comparatively larger-sized crystal. For small sized-crystal, the observed color redistribution is seen to be weak and restricted to the crystal vicinity only whereas the color changes are more

  7. Speeding up Boosting decision trees training

    NASA Astrophysics Data System (ADS)

    Zheng, Chao; Wei, Zhenzhong

    2015-10-01

    To overcome the drawback that Boosting decision trees perform fast speed in the test time while the training process is relatively too slow to meet the requirements of applications with real-time learning, we propose a fast decision trees training method by pruning those noneffective features in advance. And basing on this method, we also design a fast Boosting decision trees training algorithm. Firstly, we analyze the structure of each decision trees node, and prove that the classification error of each node has a bound through derivation. Then, by using the error boundary to prune non-effective features in the early stage, we greatly accelerate the decision tree training process, and would not affect the training results at all. Finally, the decision tree accelerated training method is integrated into the general Boosting process forming a fast boosting decision trees training algorithm. This algorithm is not a new variant of Boosting, on the contrary, it should be used in conjunction with existing Boosting algorithms to achieve more training acceleration. To test the algorithm's speedup performance and performance combined with other accelerated algorithms, the original AdaBoost and two typical acceleration algorithms LazyBoost and StochasticBoost were respectively used in conjunction with this algorithm into three fast versions, and their classification performance was tested by using the Lsis face database which contained 12788 images. Experimental results reveal that this fast algorithm can achieve more than double training speedup without affecting the results of the trained classifier, and can be combined with other acceleration algorithms. Key words: Boosting algorithm, decision trees, classifier training, preliminary classification error, face detection

  8. Development of a Technique for Measuring Local Electric Field Turbulence in a Tokamak Plasma

    NASA Astrophysics Data System (ADS)

    Thompson, D. S.; Fonck, R. J.; Burke, M. G.; McKee, G. R.; Lewicki, B. T.; Winz, G. R.

    2013-10-01

    Accessible methods for measuring Ẽ (R , t) in large-scale magnetic confinement experiments are highly desired for validation studies of plasma turbulence models. A new technique based on neutral beam emission spectroscopy is being developed to address this need. Rapid fluctuations in the separation of spectral components of the motionally induced Stark spectrum can reflect fluctuations in the intrinsic electric field of the plasma. Polarization spectroscopy via high resolution, high-throughput spectrometers that compensate for field-of-view broadening is being developed to isolate and measure these fluctuations. Cross-power correlation analysis between the linewidth fluctuations and plasma density fluctuations will be employed to extract the expected small signals. Electric field fluctuations at mid-minor-radius, normalized to an estimated MSE field, are expected to be on the order of Ẽ /EMSE ~ 1 ×10-3 in the PEGASUS Toroidal Experiment and are comparable to those expected in NSTX and in DIII-D. Work supported by US DOE Grant DE-FG02-89ER53296.

  9. Optical coherence-based techniques for motional Stark effect measurements of magnetic field pitch angle

    NASA Astrophysics Data System (ADS)

    Howard, John

    1999-02-01

    The motional Stark effect measurement of magnetic field pitch angle in tokamaks is a mature and powerful technique for estimating plasma current density in tokamaks. However, its range of applicability is limited by the requirement that 0741-3335/41/2/012/img3 and 0741-3335/41/2/012/img4 manifolds are spectrally sufficiently well separated (high magnetic fields, high beam energies) to ensure adequate net polarization for a successful measurement. This paper proposes alternative schemes based on the optical coherence properties of the Stark multiplet that are somewhat more versatile than the standard method and better suited to measurements on low-field toroidal confinement devices. An interference filter is used to transmit the Stark multiplet to a polarimeter (which uses a single photoelastic plate) that modulates the light temporal coherence and/or its first spectral moment. This light is subsequently processed using a novel electro-optically modulated solid-state interferometer that is sensitive to low-order spectral moments. The modulation of these quantities conveys information about the orientation of the light polarization and hence the magnetic field pitch angle.

  10. Optimal beam design on intensity-modulated radiation therapy with simultaneous integrated boost in nasopharyngeal cancer

    SciTech Connect

    Cheng, Mei-Chun; Hu, Yu-Wen; Liu, Ching-Sheng; Lee, Jeun-Shenn; Huang, Pin-I; Yen, Sang-Hue; Lee, Yuh-Lin; Hsieh, Chun-Mei; Shiau, Cheng-Ying

    2014-10-01

    This study aims to determine the optimal beam design among various combinations of field numbers and beam trajectories for intensity-modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB) technique for the treatment of nasopharyngeal cancer (NPC). We used 10 fields with gantry angles of 155°, 130°, 75°, 25°, 0° L, 0° R, 335°, 285°, 230°, and 205° denoted as F10. To decrease doses in the spinal cord, the F10 technique was designed by featuring 2 pairs of split-opposed beam fields at 155° to 335° and 205° to 25°, as well as one pair of manually split beam fields at 0°. The F10 technique was compared with 4 other common field arrangements: F7E, 7 fields with 50° equally spaced gantry angles; F7, the basis of F10 with 155°, 130°, 75°, 0°, 285°, 230°, and 205°; F9E, 9 fields with 40° equally spaced gantry angles; and FP, 7 posterior fields with 180°, 150°, 120°, 90°, 270°, 240°, and 210°. For each individual case of 10 patients, the customized constraints derived after optimization with the standard F10 technique were applied to 4 other field arrangements. The 4 new optimized plans of each individual case were normalized to achieve the same coverage of planning target volume (PTV){sub 63} {sub Gy} as that of the standard F10 technique. The F10 field arrangement exhibited the best coverage in PTV{sub 70} {sub Gy} and the least mean dose in the trachea-esophagus region. Furthermore, the F10 field arrangement demonstrated the highest level of conformity in the low-dose region and the least monitor unit. The F10 field arrangement performed more outstandingly than the other field arrangements in PTV{sub 70} {sub Gy} coverage and spared the central organ. This arrangement also exhibited the highest conformity and delivery efficiency. The F10 technique is recommended as the standard beam geometry for the SIB-IMRT of NPC.

  11. Characterization of nanosecond pulse electrical field shock waves using imaging techniques

    NASA Astrophysics Data System (ADS)

    Mimun, L. Chris; Ibey, Bennett L.; Roth, Caleb C.; Barnes, Ronald A.; Sardar, Dhiraj K.; Beier, Hope T.

    2015-03-01

    Nanosecond pulsed electric fields (nsPEF) cause the formation of small pores, termed nanopores, in the membrane of cells. Current nanoporation models treat nsPEF exposure as a purely electromagnetic phenomenon, but recent publications showing pressure transients, ROS production, temperature gradients, and pH waves suggest the stimulus may be physically and chemically multifactorial causing elicitation of diverse biological conditions and stressors. Our research group's goal is to quantify the breadth and participation of these stressors generated during nsPEF exposure and determine their relative importance to the observed cellular response. In this paper, we used advanced imaging techniques to identify a possible source of nsPEF-induced acoustic shock waves. nsPEFs were delivered in an aqueous media via a pair of 125 μm tungsten electrodes separated by 100 μm, mirroring our previously published cellular exposure experiments. To visualize any pressure transients emanating from the electrodes or surrounding medium, we used the Schlieren imaging technique. Resulting images and measurements confirmed that mechanical pressure waves and electrode-based stresses are formed during nsPEF, resulting in a clearer understanding of the whole exposure dosimetry. This information will be used to better quantify the impact of nsPEF-induced acoustic shock waves on cells, and has provided further evidence of non-electrical-field induced exposures for elicitation of bioieffects.

  12. An Automatic Technique for Finding Faint Moving Objects in Wide Field CCD Images

    NASA Astrophysics Data System (ADS)

    Hainaut, O. R.; Meech, K. J.

    1996-09-01

    The traditional method used to find moving objects in astronomical images is to blink pairs or series of frames after registering them to align the background objects. While this technique is extremely efficient in terms of the low signal-to-noise ratio that the human sight can detect, it proved to be extremely time-, brain- and eyesight-consuming. The wide-field images provided by the large CCD mosaic recently built at IfA cover a field of view of 20 to 30' over 8192(2) pixels. Blinking such images is an enormous task, comparable to that of blinking large photographic plates. However, as the data are available digitally (each image occupying 260Mb of disk space), we are developing a set of computer codes to perform the moving object identification in sets of frames. This poster will describe the techniques we use in order to reach a detection efficiency as good as that of a human blinker; the main steps are to find all the objects in each frame (for which we rely on ``S-Extractor'' (Bertin & Arnouts (1996), A&ASS 117, 393), then identify all the background objects, and finally to search the non-background objects for sources moving in a coherent fashion. We will also describe the results of this method applied to actual data from the 8k CCD mosaic. {This work is being supported, in part, by NSF grant AST 92-21318.}

  13. Analysis of field data to evaluate performance of optical remote sensing techniques to estimate fugitive emissions

    SciTech Connect

    Paine, R.J.; Lew, F.; Zwicker, J.O.; Feldman, H.

    1999-07-01

    The American Petroleum Institute (API) has developed data sets for the evaluation of dispersion modeling and optical remote sensing (ORS) techniques. An initial field study featuring several tracer gas releases from simulated point, area, and volume sources was conducted in early 1995 at an open field site (Duke Forest, North Carolina). A second experiment (Project OPTEX) took place at an operational petrochemical facility in Texas and featured tracer releases at heights up to 41 meters from points located in an active process unit. This paper discusses the results of an analysis to evaluate the capability for remote sensing techniques to estimate the magnitude and location of emission sources in an industrial complex setting. Three major issues that the paper reports on are: (1) can ORS technology be used to determine emission rates when the source locations are known; (2) can ORS technology be used to locate sources in unknown locations, therefore promising to replace or at least streamline leak detection and repair (LDAR) programs at petrochemical facilities; and (3) what are the constraints for real-time operation, interpretation, and responsiveness involving ORS technology?

  14. Investigating light NMSSM pseudoscalar states with boosted ditau tagging

    NASA Astrophysics Data System (ADS)

    Conte, Eric; Fuks, Benjamin; Guo, Jun; Li, Jinmian; Williams, Anthony G.

    2016-05-01

    We study a class of realizations of the Next-to-Minimal Supersymmetric Standard Model that is motivated by dark matter and Higgs data, and in which the lightest pseudoscalar Higgs boson mass is smaller than twice the bottom quark mass and greater than twice the tau lepton mass. In such scenarios, the lightest pseudoscalar Higgs boson can be copiously produced at the LHC from the decay of heavier superpartners and will dominantly further decay into a pair of tau leptons that is generally boosted. We make use of a boosted object tagging technique designed to tag such a ditau jet, and estimate the sensitivity of the LHC to the considered supersymmetric scenarios with 20 to 50 fb-1 of proton-proton collisions at a center-of-mass energy of 13 TeV.

  15. Externally Dispersed Interferometry for Resolution Boosting and Doppler Velocimetry

    SciTech Connect

    Erskine, D J

    2003-12-01

    Externally dispersed interferometry (EDI) is a rapidly advancing technique for wide bandwidth spectroscopy and radial velocimetry. By placing a small angle-independent interferometer near the slit of an existing spectrograph system, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moire pattern, which manifests high detailed spectral information heterodyned down to low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry (under a Doppler shift the entire moir{acute e} pattern shifts in phase). A demonstration of {approx}2x resolution boosting (100,000 from 50,000) on the Lick Obs. echelle spectrograph is shown. Preliminary data indicating {approx}8x resolution boost (170,000 from 20,000) using multiple delays has been taken on a linear grating spectrograph.

  16. Spatial Field Variability Mapping of Rice Crop using Clustering Technique from Space Borne Hyperspectral Data

    NASA Astrophysics Data System (ADS)

    Moharana, S.; Dutta, S.

    2015-12-01

    Precision farming refers to field-specific management of an agricultural crop at a spatial scale with an aim to get the highest achievable yield and to achieve this spatial information on field variability is essential. The difficulty in mapping of spatial variability occurring within an agriculture field can be revealed by employing spectral techniques in hyperspectral imagery rather than multispectral imagery. However an advanced algorithm needs to be developed to fully make use of the rich information content in hyperspectral data. In the present study, potential of hyperspectral data acquired from space platform was examined to map the field variation of paddy crop and its species discrimination. This high dimensional data comprising 242 spectral narrow bands with 30m ground resolution Hyperion L1R product acquired for Assam, India (30th Sept and 3rd Oct, 2014) were allowed for necessary pre-processing steps followed by geometric correction using Hyperion L1GST product. Finally an atmospherically corrected and spatially deduced image consisting of 112 band was obtained. By employing an advanced clustering algorithm, 12 different clusters of spectral waveforms of the crop were generated from six paddy fields for each images. The findings showed that, some clusters were well discriminated representing specific rice genotypes and some clusters were mixed treating as a single rice genotype. As vegetation index (VI) is the best indicator of vegetation mapping, three ratio based VI maps were also generated and unsupervised classification was performed for it. The so obtained 12 clusters of paddy crop were mapped spatially to the derived VI maps. From these findings, the existence of heterogeneity was clearly captured in one of the 6 rice plots (rice plot no. 1) while heterogeneity was observed in rest of the 5 rice plots. The degree of heterogeneous was found more in rice plot no.6 as compared to other plots. Subsequently, spatial variability of paddy field was

  17. Increased Oil Production and Reserves from Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah

    SciTech Connect

    Deo, M.D.; Morgan, C.D.

    1999-04-28

    The objective of the project is to increase oil production and reserves by the use of improved reservoir characterization and completion techniques in the Uinta Basin, Utah. To accomplish this objective, a two-year geologic and engineering characterization of the Bluebell field was conducted. The study evaluated surface and subsurface data, currently used completion techniques, and common production problems. It was determined that advanced case- and open-hole logs could be effective in determining productive beds and that stage-interval (about 500 ft [150 m] per stage) and bed-scale isolation completion techniques could result in improved well performance. In the first demonstration well (Michelle Ute well discussed in the previous technical report), dipole shear anisotropy (anisotropy) and dual-burst thermal decay time (TDT) logs were run before and isotope tracer log was run after the treatment. The logs were very helpful in characterizing the remaining hydrocarbon potential in the well. But, mechanical failure resulted in a poor recompletion and did not result in a significant improvement in the oil production from the well.

  18. Two-dimensional refractive index profiling of optical fibers by modified refractive near-field technique

    NASA Astrophysics Data System (ADS)

    El Sayed, A.; Pilz, Soenke; Ryser, Manuel; Romano, Valerio

    2016-02-01

    The refractive index distribution in the core-cladding region of an optical fiber plays an important role in determining the transmission and dispersion properties of the waveguide. The refracted near-field technique (RNF) is among the most widespread techniques used for measuring the refractive index profile of optical fibers and is based on illuminating the end-facet of a fiber with a focused beam whose vertex angle greatly exceeds the acceptance angle of the fiber, which is immersed in an index matching liquid. What one observes are then the refracted unguided rays rather than the guided rays. Nevertheless, the standard refracted near-field technique cannot be applied to a wide range of optical fibers e.g. if their shapes are not axially symmetric. In this work we demonstrate a modified method which allows 2-D imaging of the refractive index profile and thereby overcoming the axial symmetric limitation of the standard RNF. The new system is operating at 630 nm and based on the same principle of the RNF, but the optical path is reversed so that the light at the fiber end-facet is collected by an objective lens and detected by a CCD camera. The method does not require scanning over the fiber end-facet. Thus the system is faster and less sensitive to vibrations and external conditions compared to the standard RNF, furthermore it allows averaging to improve the signal to noise ratio. The spatial resolution of the system is determined by the numerical aperture of the objective and by the resolution of the CCD camera. To calibrate the setup, a reference multi-step index fiber provided by National Physical Laboratory was used.

  19. Program for field validation of the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT UT)

    NASA Astrophysics Data System (ADS)

    Hamlin, D. R.

    1985-11-01

    This final report describes work performed by Southwest Research Institute for the Nuclear Regulatory Commission (NRC) in fulfillment of NRC Contract No. NRC-04-77-145; "Program for Field Validation of the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT UT)." The purpose was to validate the effectiveness of SAFT UT as a nondestructive examination technique for nuclear power and other related industries. SAFT UT is an ultrasonic imaging method for accurate measurement of the spatial location and extent of acoustically reflective surfaces (flaws) contained in objects such as structural components and weldments in nuclear power reactor systems. The increased measurement accuracy offered by SAFT, when compared with that provided by measurement methods now in use, will improve the reliability of flaw severity assessment with resultant safety and economic benefits to the nuclear power industry. This report presents a comprehensive discussion of the work accomplished in evaluating the performance capabilities of the developed SAFT UT inspection system. Inspection results obtained using both 0-degree longitudinal and angle-beam operating modes are presented. These results include laboratory and nuclear power plant field site examinations on a variety of defect types contained within carbon and stainless steel flat plate and cylindrical test specimens or components. The SAFT UT processed data flaw images are evaluated by comparing them to results obtained from destructive sectioning or by using flaw fabrication data which predicted actual flaw depth, orientation and size. On the basis of these evaluations, conclusions are presented which summarize the performance capabilities of the SAFT UT inspection technique.

  20. The efficacy of field techniques for obtaining and storing blood samples from fishes.

    PubMed

    Clark, T D; Donaldson, M R; Drenner, S M; Hinch, S G; Patterson, D A; Hills, J; Ives, V; Carter, J J; Cooke, S J; Farrell, A P

    2011-11-01

    Prompted by the dramatic increase in the use of blood analyses in fisheries research and monitoring, this study investigated the efficacy of common field techniques for sampling and storing blood from fishes. Three questions were addressed: (1) Do blood samples taken via rapid caudal puncture (the 'grab-and-stab' technique) yield similar results for live v. sacrificed groups of fishes? (2) Do rapidly obtained caudal blood samples accurately represent blood properties of fishes prior to capture? (3) Does storage of whole blood in an ice slurry for a working day (8·5 h) modify the properties of the plasma? It was shown that haematocrit, plasma ions, metabolites, stress hormones and sex hormones of caudal blood samples were statistically similar when taken from live v. recently sacrificed groups of adult coho salmon Oncorhynchus kisutch. Moreover, this study confirmed by using paired blood samples from cannulated O. kisutch that blood acquired through the caudal puncture technique (mean ±s.e. 142 ± 26 s after capture) was representative of fish prior to capture. Long-term (8·5 h) cold storage of sockeye salmon Oncorhynchus nerka whole blood caused significant decreases in plasma potassium and chloride, and a significant increase in plasma glucose. Previous research has suggested that these changes largely result from net movements of ions and molecules between the plasma and erythrocytes, movements that can occur within minutes of storage. Thus, blood samples from fishes should be centrifuged as quickly as practicable in the field for separation of plasma and erythrocytes to prevent potentially misleading data. PMID:22026608

  1. Bagging and boosting negatively correlated neural networks.

    PubMed

    Islam, Md Monirul; Yao, Xin; Shahriar Nirjon, S M Shahriar; Islam, Muhammad Asiful; Murase, Kazuyuki

    2008-06-01

    In this paper, we propose two cooperative ensemble learning algorithms, i.e., NegBagg and NegBoost, for designing neural network (NN) ensembles. The proposed algorithms incrementally train different individual NNs in an ensemble using the negative correlation learning algorithm. Bagging and boosting algorithms are used in NegBagg and NegBoost, respectively, to create different training sets for different NNs in the ensemble. The idea behind using negative correlation learning in conjunction with the bagging/boosting algorithm is to facilitate interaction and cooperation among NNs during their training. Both NegBagg and NegBoost use a constructive approach to automatically determine the number of hidden neurons for NNs. NegBoost also uses the constructive approach to automatically determine the number of NNs for the ensemble. The two algorithms have been tested on a number of benchmark problems in machine learning and NNs, including Australian credit card assessment, breast cancer, diabetes, glass, heart disease, letter recognition, satellite, soybean, and waveform problems. The experimental results show that NegBagg and NegBoost require a small number of training epochs to produce compact NN ensembles with good generalization. PMID:18558541

  2. Three-component velocity field measurements of propeller wake using a stereoscopic PIV technique

    NASA Astrophysics Data System (ADS)

    Lee, Sang Joon; Paik, Bu Geun; Yoon, Jong Hwan; Lee, Choung Mook

    A stereoscopic PIV (Particle Image Velocimetry) technique was used to measure the three-dimensional flow structure of the turbulent wake behind a marine propeller with five blades. The out-of-plane velocity component was determined using two CCD cameras with an angular displacement configuration. Four hundred instantaneous velocity fields were measured for each of four different blade phases, and ensemble averaged in order to find the spatial evolution of the propeller wake in the region from the trailing edge up to one propeller diameter (D) downstream. The influence of propeller loading conditions on the wake structure was also investigated by measuring the velocity fields at three advance ratios (J=0.59, 0.72 and 0.88). The phase-averaged velocity fields revealed that a viscous wake formed by the boundary layers developed along the blade surfaces. Tip vortices were generated periodically and the slipstream contracted in the near-wake region. The out-of-plane velocity component and strain rate had large values at the locations of the tip and trailing vortices. As the flow moved downstream, the turbulence intensity, the strength of the tip vortices, and the magnitude of the out-of-plane velocity component at trailing vortices all decreased due to effects such as viscous dissipation, turbulence diffusion, and blade-to-blade interaction.

  3. TRAINING-INDUCED CHANGES IN DRAG-FLICK TECHNIQUE IN FEMALE FIELD HOCKEY PLAYERS

    PubMed Central

    Gómez, M.; Martín-Casado, L.; Navarro, E.

    2012-01-01

    The penalty corner is one of the most important goal plays in field hockey. The drag-flick is used less by women than men in a penalty corner. The aim of this study was to describe training-induced changes in the drag-flick technique in female field hockey players. Four female players participated in the study. The VICON optoelectronic system (Oxford Metrics, Oxford, UK) measured the kinematic parameters of the drag-flick with six cameras sampling at 250 Hz, prior to and after training. Fifteen shots were captured for each subject. A Wilcoxon test assessed the differences between pre-training and post-training parameters. Two players received specific training twice a week for 8 weeks; the other two players did not train. The proposed drills improved the position of the stick at the beginning of the shot (p < 0.05), the total distance of the shot (p < 0.05) and the rotation radius at ball release (p < 0.01). It was noted that all players had lost speed of the previous run. Further studies should include a larger sample, in order to provide more information on field hockey performance. PMID:24868116

  4. Training-induced changes in drag-flick technique in female field hockey players.

    PubMed

    de Subijana, C L; Gómez, M; Martín-Casado, L; Navarro, E

    2012-12-01

    The penalty corner is one of the most important goal plays in field hockey. The drag-flick is used less by women than men in a penalty corner. The aim of this study was to describe training-induced changes in the drag-flick technique in female field hockey players. Four female players participated in the study. The VICON optoelectronic system (Oxford Metrics, Oxford, UK) measured the kinematic parameters of the drag-flick with six cameras sampling at 250 Hz, prior to and after training. Fifteen shots were captured for each subject. A Wilcoxon test assessed the differences between pre-training and post-training parameters. Two players received specific training twice a week for 8 weeks; the other two players did not train. The proposed drills improved the position of the stick at the beginning of the shot (p < 0.05), the total distance of the shot (p < 0.05) and the rotation radius at ball release (p < 0.01). It was noted that all players had lost speed of the previous run. Further studies should include a larger sample, in order to provide more information on field hockey performance. PMID:24868116

  5. A field comparison of techniques to quantify surface water - groundwater interactions

    NASA Astrophysics Data System (ADS)

    Gonzalez-Pinzon, R.; Ward, A. S.; Hatch, C. E.; Wlostowski, A. N.; Singha, K.; Gooseff, M. N.; Haggerty, R.; Harvey, J. W.; Cirpka, O. A.; Brock, J. T.

    2014-12-01

    The challenge of quantifying surface water-groundwater interactions has led to the development of several techniques, from centimeter-scale probes to whole-system tracers, including chemical, thermal, and electrical methods. We co-applied several of these techniques within a single experimental reach in a third-order stream. The techniques that we used include: conservative and "smart" reactive solute tracer tests, measurement of hydraulic heads, distributed temperature sensing, vertical profiles of solute tracer and temperature in the streambed, and electrical resistivity imaging. Results from the field experiment consistently indicated that surface water-groundwater interactions were not spatially expansive, but were high in flux through a shallow hyporheic zone surrounding the 450-m study reach. The NaCl and resazurin tracers suggested different surface-subsurface exchange patterns between the upper two thirds and lower third of the reach. Subsurface sampling of tracers and vertical thermal profiles quantified relatively high fluxes through a 10-20 cm deep hyporheic zone with chemical reactivity of resazurin indicated at 3, 6 and 9 cm sampling depths. Monitoring of hydraulic gradients along transects starting ~ 40 m away from the stream indicated that groundwater flow prevented the development of a larger hyporheic zone, which was shown (from MINIPOINT samples) to progressively vanish from the stream thalweg with depth in the streambed and distance toward the banks. Finally, FO-DTS did not detect extensive inflow of groundwater into the stream and electrical resistivity imaging showed limited large-scale hyporheic exchange. From the experience gained in our experiment, we recommend the following reasoning to decide which technique(s) should be implemented in a particular study: 1) clearly define the nature of the questions to be addressed, i.e., physical, biological or chemical processes, 2) identify the spatial and temporal scales that want to be covered

  6. Application of Strong Field Physics Techniques to X-Ray Free Electron Laser Science

    NASA Astrophysics Data System (ADS)

    Roedig, Christoph Antony

    With the commissioning of the Linac Coherent Light Source (LCLS), the first x-ray free electron laser (XFEL) was realized at the Stanford Linear Accelerator Center. This novel device brings an unprecedented parameter set to a diverse community of scientists. The short wavelengths and short pulse durations enable an entire new class of time resolved structural analysis. The imaging capabilities enabled by the machine will lead to many breakthroughs in the fields of biophysics and nano technology. With the new capabilities of the LCLS come many challenges. The understanding required to effectively utilize the XFEL on complex molecular or biological systems goes back to the basic atomic physics of the interaction of light and matter. The parameter set of this machine is as unprecedented as it will be untested. To make informed measurements with the LCLS beam, a set of novel diagnostic techniques will be required. This report outlines major contributions made to the early experimental atomic physics and diagnostic efforts at LCLS. Building on a rich history of techniques used for ultra short optical lasers and atomic physics experimentation, a diagnostic instrument and experimental techniques are developed to make spectral, energy and temporal measurements of the LCLS pulses possible. Expanding on earlier studies of ionization performed on optical lasers and synchrotron sources, new ionization mechanisms such as multiphoton ionization in the x-ray regime are observed. Leveraging the unique combination of hard x-ray photon energy, extremely short pulse duration and high pulse energy, a technique for the time resolved study of ultrafast inner shell electronic relaxation processes is developed and studied for feasibility. The common theme to the efforts described here is the advancement of proven techniques and interesting atomic physics phenomena to the next generation of ultra short pulsed x-ray laser systems. The atomic physics explored here lay the groundwork for the

  7. Establishing the skill of climate field reconstruction techniques for precipitation with pseudoproxy experiments in Europe

    NASA Astrophysics Data System (ADS)

    Wagner, S.; Gomez-Navarro, J. J.; Zorita, E.; Werner, J.; Luterbacher, J.

    2014-12-01

    In recent years important efforts were focused in the development of Climate Field Reconstructions (CFR). These techniques allow merging a limited number of local reconstructions to produce a regular grid which accommodates climatic information from different proxy sources. Pseudo Proxy Experiments (PPE) are idealized experiments performed with synthetic data, typically generated with comprehensive climate models. The PPEs aim at assessing the accuracy that can be expected by (statistical) state-of-the-art reconstruction techniques, but also at identifying potential shortcomings and improvements.In this study a number of PPEs are investigated in order to assess the ability of three different CFR techniques to reconstruct precipitation over Europe. The methods comprise of a linear fit (Canonical Correlation Analysis, CCA), a simple non-linear approach (the Analog Method, AM) and a Bayesian model (Bayesian Hierarchical Method, BHM). Given the inherent complexity of this variable, hardly reproduced by state-of-the-art global circulation models, some downscaling technique is necessary to design meaningful PPEs. In this study the synthetic data consist of a high-resolution climate simulation performed with a Regional Climate Model over Europe for the last two Millennia. Results indicate that unlike BHM, CCA systematically underestimates the variance. TheAM can be adjusted to overcome this shortcoming, presenting an intermediate behavior between the two aforementioned techniques. However, a trade-off between reconstruction target correlations and reconstructed variance is the drawback common to all CFR techniques. CCA (BHM) represent the largest (lowest) skill in preserving the temporal evolution, whereas the AM can be tuned to reproduce better correlation at the expense of a loss in variance. While BHM, in the form employed here, has been shown to perform well for temperatures, it does heavily rely on prescribed spatial correlation lengths. For temperature this

  8. Field test of an autocorrelation technique for determining grain size using a digital camera

    NASA Astrophysics Data System (ADS)

    Barnard, P. L.; Rubin, D. M.; Harney, J.; Mustain, N.

    2007-12-01

    An extensive field test using Rubin's (2004) autocorrelation technique shows that median and mean grain size can be determined with suitable accuracy using a digital camera and associated autocorrelation when compared to traditional methods such as mechanical sieving and settling-tube analysis. The field test included 205 sediment samples and > 1200 digital images from a variety of beaches on the west coast of the United States, with grain sizes ranging from sand to granules. To test the accuracy of the digital-image grain-size algorithm, we compared results with manual point counts of a large image data set in the Santa Barbara littoral cell. Grain sizes calculated using the autocorrelation algorithm were highly correlated with the point counts of the same images (r2=0.93; n=79) and had an error of only 1%. Although grain sizes calculated from digital images give an accurate result for grains in the image, natural lateral and vertical variability in grain size can cause differences between grain size measured in digital images of the bed surface and grain size measured by sieving a grab sample that includes subsurface sediment. Lateral spatial variability was tested by analyzing the results of up to 100 images taken in a series of 1 m2 sample areas. Comparisons of calculated grain sizes and grain sizes measured from grab samples show small differences between surface sediment and grab samples on high- energy dissipative beaches with well-sorted sediment such as in the Pacific Northwest (r2 > 0.92; n=115). In contrast, on less dissipative, more poorly sorted beaches such as Ocean Beach in San Francisco, differences between surface and subsurface grain size are greater (r2 > 0.70; n=67; within 3% accuracy). In all field tests the autocorrelation method was able to predict the mean and median grain size with ~96% accuracy, which is more than adequate for the majority of sedimentological applications. When properly automated for large numbers of samples, the

  9. Application of Anisotropic Conductive Film to Fabrication of Molybdenum Field Emitter Arrays Using Transfer Mold Technique

    NASA Astrophysics Data System (ADS)

    Cho, Eou Sik; Ahn, Min Hyung; Kwon, Sang Jik

    2008-08-01

    In the fabrication of molybdenum field emitter arrays (Mo FEA) by the transfer mold technique, anisotropic conductive film (ACF) was applied to the bond between the inverted mold structure and the transferred glass substrate. Without any electrical treatment of electrostatic bonding, the inverted mold was successfully bonded to an indium tin oxide (ITO) glass substrate under optimized thermal and pressure conditions. No additional conductive layers were used in the bonding process, and the bonded ACF was not chemically affected in the wet-etch process of the silicon inverted mold structure. The fabricated Mo FEA was structurally and electrically investigated and an anode current of 10 nA per emitter was obtained at a gate bias of 94 V. The results demonstrate the possibility of selective conduction in the fabrication of transfer mold FEA using ACF bonding.

  10. A field technique for estimating aquifer parameters using flow log data

    USGS Publications Warehouse

    Paillet, Frederick L.

    2000-01-01

    A numerical model is used to predict flow along intervals between producing zones in open boreholes for comparison with measurements of borehole flow. The model gives flow under quasi-steady conditions as a function of the transmissivity and hydraulic head in an arbitrary number of zones communicating with each other along open boreholes. The theory shows that the amount of inflow to or outflow from the borehole under any one flow condition may not indicate relative zone transmissivity. A unique inversion for both hydraulic-head and transmissivity values is possible if flow is measured under two different conditions such as ambient and quasi-steady pumping, and if the difference in open-borehole water level between the two flow conditions is measured. The technique is shown to give useful estimates of water levels and transmissivities of two or more water-producing zones intersecting a single interval of open borehole under typical field conditions. Although the modeling technique involves some approximation, the principle limit on the accuracy of the method under field conditions is the measurement error in the flow log data. Flow measurements and pumping conditions are usually adjusted so that transmissivity estimates are most accurate for the most transmissive zones, and relative measurement error is proportionately larger for less transmissive zones. The most effective general application of the borehole-flow model results when the data are fit to models that systematically include more production zones of progressively smaller transmissivity values until model results show that all accuracy in the data set is exhausted.A numerical model is used to predict flow along intervals between producing zones in open boreholes for comparison with measurements of borehole flow. The model gives flow under quasi-steady conditions as a function of the transmissivity and hydraulic head in an arbitrary number of zones communicating with each other along open boreholes. The

  11. Behavioral scoring using programmable calculators: a technique usable in the field.

    PubMed

    Mutalik, P G; Alreja, M; Nayar, U

    1985-11-01

    A simple method of recording the time spent in various behavioral categories during behavioral scoring is described. Use is made of a programmable calculator which is made to function as a multiple timer, keeping track of each of the categories. Any number of mutually exclusive categories can be scored using a single key press, by assigning a pre-set code to each. A print-out of the analysed frequency or duration data can be obtained either concurrently or at any time after the experiment, as required. The least count of the technique is about 1-2 seconds and this precludes its use for extremely rapidly changing behaviors. Apart from this, it is convenient, time-saving and especially suitable for field use. PMID:3841218

  12. Regular Exercise May Boost Prostate Cancer Survival

    MedlinePlus

    ... nih.gov/medlineplus/news/fullstory_158374.html Regular Exercise May Boost Prostate Cancer Survival Study found that ... HealthDay News) -- Sticking to a moderate or intense exercise regimen may improve a man's odds of surviving ...

  13. Do ADHD Medicines Boost Substance Abuse Risk?

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_159904.html Do ADHD Medicines Boost Substance Abuse Risk? Chances were actually ... that their children who take stimulants to treat attention deficit hyperactivity disorder (ADHD) may be at higher risk for substance ...

  14. Anemia Boosts Stroke Death Risk, Study Finds

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_160476.html Anemia Boosts Stroke Death Risk, Study Finds Blood condition ... 2016 (HealthDay News) -- Older stroke victims suffering from anemia -- a lack of red blood cells -- may have ...

  15. Avoiding Anemia: Boost Your Red Blood Cells

    MedlinePlus

    ... link, please review our exit disclaimer . Subscribe Avoiding Anemia Boost Your Red Blood Cells If you’re ... and sluggish, you might have a condition called anemia. Anemia is a common blood disorder that many ...

  16. Old Drug Boosts Brain's Memory Centers

    MedlinePlus

    ... medlineplus/news/fullstory_159605.html Old Drug Boosts Brain's Memory Centers But more research needed before recommending ... called methylene blue may rev up activity in brain regions involved in short-term memory and attention, ...

  17. Tools to Boost Steam System Efficiency

    SciTech Connect

    2005-05-01

    The Steam System Scoping Tool quickly evaluates your entire steam system operation and spots the areas that are the best opportunities for improvement. The tool suggests a range of ways to save steam energy and boost productivity.

  18. Old Drug Boosts Brain's Memory Centers

    MedlinePlus

    ... gov/news/fullstory_159605.html Old Drug Boosts Brain's Memory Centers But more research needed before recommending ... called methylene blue may rev up activity in brain regions involved in short-term memory and attention, ...

  19. Engineering report: Oxygen boost compressor study

    NASA Technical Reports Server (NTRS)

    Tera, L. S.

    1974-01-01

    An oxygen boost compressor is described which supports a self-contained life support system. A preliminary analysis of the compressor is presented along with performance test results, and recommendations for follow-on efforts.

  20. Relativistic projection and boost of solitons

    SciTech Connect

    Wilets, L.

    1991-12-31

    This report discusses the following topics on the relativistic projection and boost of solitons: The center of mass problem; momentum eigenstates; variation after projection; and the nucleon as a composite. (LSP).

  1. Relativistic projection and boost of solitons

    SciTech Connect

    Wilets, L.

    1991-01-01

    This report discusses the following topics on the relativistic projection and boost of solitons: The center of mass problem; momentum eigenstates; variation after projection; and the nucleon as a composite. (LSP).

  2. Establishing the skill of climate field reconstruction techniques for precipitation with pseudoproxy experiments

    NASA Astrophysics Data System (ADS)

    Gómez-Navarro, Juan José; Werner, Johannes; Wagner, Sebastian; Luterbacher, Jürg; Zorita, Eduardo

    2015-09-01

    This study aims at assessing the skill of several climate field reconstruction techniques (CFR) to reconstruct past precipitation over continental Europe and the Mediterranean at seasonal time scales over the last two millennia from proxy records. A number of pseudoproxy experiments are performed within the virtual reality of a regional paleoclimate simulation at 45 km resolution to analyse different aspects of reconstruction skill. Canonical Correlation Analysis (CCA), two versions of an Analog Method (AM) and Bayesian hierarchical modeling (BHM) are applied to reconstruct precipitation from a synthetic network of pseudoproxies that are contaminated with various types of noise. The skill of the derived reconstructions is assessed through comparison with precipitation simulated by the regional climate model. Unlike BHM, CCA systematically underestimates the variance. The AM can be adjusted to overcome this shortcoming, presenting an intermediate behaviour between the two aforementioned techniques. However, a trade-off between reconstruction-target correlations and reconstructed variance is the drawback of all CFR techniques. CCA (BHM) presents the largest (lowest) skill in preserving the temporal evolution, whereas the AM can be tuned to reproduce better correlation at the expense of losing variance. While BHM has been shown to perform well for temperatures, it relies heavily on prescribed spatial correlation lengths. While this assumption is valid for temperature, it is hardly warranted for precipitation. In general, none of the methods outperforms the other. All experiments agree that a dense and regularly distributed proxy network is required to reconstruct precipitation accurately, reflecting its high spatial and temporal variability. This is especially true in summer, when a specifically short de-correlation distance from the proxy location is caused by localised summertime convective precipitation events.

  3. Processing discontinuous displacement fields by a spatio-temporal derivative technique

    NASA Astrophysics Data System (ADS)

    Sousa, A. M. R.; Xavier, J.; Morais, J. J. L.; Filipe, V. M. J.; Vaz, M.

    2011-12-01

    In this paper, a digital image correlation (DIC) method coupling cross-correlation with spatio-temporal differential techniques was proposed for assessing discontinuous displacement fields. The accuracy and robustness of the algorithm was assessed on a set of numerical tests by processing computer generated speckled-pattern images. Fracture mechanical tests in mode I were considered, in which both in-plane and out-of-plane rigid-body movements were taken into account. The ability for recovering the analytical asymptotic displacement field in mode I was analysed, and stress intensity factor, crack opening displacement and crack tip location were used as quantitative parameters for validation purposes. Throughout these tests, the results obtained with the proposed method were systematically compared to the ones from Aramis DIC-2D commercial code. Globally, the results computed from both methods are in good agreement with reference values. However, due to the high spatial resolution (point-wise characteristic), a better matching of the displacements in the neighbour of discontinuities could be obtained by the proposed method.

  4. Combination of various observation techniques for regional modeling of the gravity field

    NASA Astrophysics Data System (ADS)

    Lieb, Verena; Schmidt, Michael; Dettmering, Denise; Börger, Klaus

    2016-05-01

    Modeling a very broad spectrum of the Earth's gravity field needs observations from various measurement techniques with different spectral sensitivities. Typically, high-resolution regional gravity data are combined with low-resolution global observations. To exploit the gravitational information as optimally as possible, we set up a regional modeling approach using radial spherical basis functions, emphasizing the strengths of various data sets by the flexible combination of high- and middle-resolution terrestrial, airborne, shipborne, and altimetry measurements. The basis functions are defined and located in the region of interest in such a manner, which the highest measure of information of the input data is captured. Any functional of the Earth's gravity field can be derived, as, e.g., quasi-geoid heights or gravity anomalies. Here we present results of a study area in Northern Germany. A comprehensive cross validation to external observation data delivers standard deviations less than 5 cm. Differences to an existing regional quasi-geoid model count on average ±6 cm and proof the plausibility of our solution. The comparison with existing global models reaches higher standard deviations for the more sensitive gravity anomalies as for quasi-geoid heights, showing the additional value of our solution in the high frequency domain. Covering a broad frequency spectrum, our regional models can be used as basis for various applications, such as refinement of global models, national geoid determination, and detection of mass anomalies in the Earth's interior.

  5. Integrating remote sensing techniques at Cuprite, Nevada: AVIRIS, Thematic Mapper, and field spectroscopy

    NASA Technical Reports Server (NTRS)

    Hill, Bradley; Nash, Greg; Ridd, Merrill; Hauff, Phoebe L.; Ebel, Phil

    1992-01-01

    The Cuprite mining district in southwestern Nevada has become a test site for remote sensing studies with numerous airborne scanners and ground sensor data sets collected over the past fifteen years. Structurally, the Cuprite region can be divided into two areas with slightly different alteration and mineralogy. These zones lie on either side of a postulated low-angle structural discontinuity that strikes nearly parallel to US Route 95. Hydrothermal alternation at Cuprite was classified into three major zones: silicified, opalized, and argillized. These alteration types form a bulls-eye pattern east of the highway and are more linear on the west side of the highway making a striking contrast from the air and the imagery. Cuprite is therefore an ideal location for remote sensing research as it exhibits easily identified hydrothermal zoning, is relatively devoid of vegetation, and contains a distinctive spectrally diagnostic mineral suite including the ammonium feldspar buddingtonite, several types of alunite, different jarosites, illite, kaolinite, smectite, dickite, and opal. This present study brings a new dimension to these previous remote sensing and ground data sets compiled for Cuprite. The development of a higher resolution field spectrometer now provides the capability to combine extensive in-situ mineralogical data with a new geologic field survey and detailed Airborne Visible/Infrared Imaging Spectrometers (AVIRIS) images. The various data collection methods and the refinement of the integrated techniques are discussed.

  6. A Dosimetric Analysis of IMRT and Multistatic Fields Techniques for Left Breast Radiotherapy

    SciTech Connect

    Moon, Seong Kwon; Kim, Yeon Sil; Kim, Soo Young; Lee, Mi Jo; Keum, Hyun Sup; Kim, Seung Jin; Youn, Seon Min

    2011-10-01

    The purpose of this study was to analyze the dosimetric difference between intensity-modulated radiation therapy (IMRT) using 3 or 5 beams and multistatic field technique (MSF) in radiotherapy of the left breast. We made comparative analysis of two kinds of radiotherapy that can achieve improved dose homogeneity. First is a MSF that uses both major and small irradiation fields at the same time. The other is IMRT using 3 or 5 beams with an inverse planning system using multiple static multileaf collimators. We made treatment plans for 16 early left breast cancer patients who were randomly selected and had undergone breast conserving surgery and radiotherapy, and analyzed them in the dosimetric aspect. For the mean values of V{sub 95} and dose homogeneity index, no statistically significant difference was observed among the three therapies. Extreme hot spots receiving >110% of prescribed dose were not found in any of the three methods. Using Tukey's test, IMRT showed a significantly larger increase in exposure dose to the ipsilateral lung and the heart than MSF in the low-dose area, but in the high-dose area, MSF showed a slight increase. To improve dose homogeneity, the application of MSF, which can be easily planned and applied more widely, is considered optimal as an alternative to IMRT for radiotherapy of early left breast cancer.

  7. A poloidal field measurement technique: Pitch angle measurements via injected He/sup +/ ions

    SciTech Connect

    Jobes, F.C.

    1989-07-01

    The poloidal field of a tokamak can be determined by observing the light emitted by He/sup +/ ions injected into the plasma by a perpendicular He/sup 0/ beam. These ions will orbit in small circles located where the neutral atom became ionized, and they will remain there for a few microseconds. During this time, some of these ions will also emit light at various spectral lines. The observed spectrum of any of these lines will have a peculiar and very wide shape, and it will be offset (Doppler shifted) with respect to the natural line location. The location and width of the spectral pattern provide independent information about the components of the poloidal field which are parallel and perpendicular to the beam velocity, and this information is local to the point where the light is emitted. For a horizontal beam, these components are b/sub x/ and b/sub y/, respectively. The difference in Doppler shift between two measurement points above one another (at the top and bottom of the beam) is directly proportional to /delta/b/sub x/, which in turn is proportional to the transform on that flux surface. Thus, this technique provides a means to measure directly local values of q(r). Simulation studies indicate that accurate measurements can be made in milliseconds. 6 refs., 8 figs.

  8. Flexible reduced field of view magnetic resonance imaging based on single-shot spatiotemporally encoded technique

    NASA Astrophysics Data System (ADS)

    Li, Jing; Cai, Cong-Bo; Chen, Lin; Chen, Ying; Qu, Xiao-Bo; Cai, Shu-Hui

    2015-10-01

    In many ultrafast imaging applications, the reduced field-of-view (rFOV) technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporally-encoded (SPEN) method offers an inherent applicability to rFOV imaging. In this study, a flexible rFOV imaging method is presented and the superiority of the SPEN approach in rFOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging (EPI) experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the rFOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest (ROIs) with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474236, 81171331, and U1232212).

  9. Two-phase flow measurement by chemical tracer technique for Uenotai geothermal field in Japan

    SciTech Connect

    Sato, Tatsuya; Osato, Kazumi; Hirtz, P.

    1996-12-31

    A tracer flow-test (TFT) survey of three production wells was performed in February, 1996, for Akita Geothermal Energy Co., Ltd. (AGECO) at the Uenotai geothermal field in the Akita prefecture of northern Honshu, Japan. The survey was conducted as a demonstration test of the chemical tracer method for two-phase flow measurement. Although the tracer method has been in commercial use for about 4 years this was the first time the technique had been applied on wells with mixing runs of less than 12 meters. The tracers were injected through the wing valve on the side of the wellheads to maximize the tracer dispersion through the 9 meters of pipeline available before sample collection. The three wells tested had steam fractions at the wellhead of 38 to 99.4 % by weight and total flow rates of 31.5 to 51.5 tons/hr. Based on the test results the chemical tracer method is considered accurate under the conditions experienced at the Uenotai geothermal field and has been adopted for routine flow rate and enthalpy monitoring.

  10. Measurement of the geometric characteristics of a fire front by stereovision techniques on field experiments

    NASA Astrophysics Data System (ADS)

    Rossi, L.; Molinier, T.; Pieri, A.; Akhloufi, M.; Tison, Y.; Bosseur, F.

    2011-12-01

    This paper presents stereovision techniques for measurement of the geometrical properties (position, rate of spread, fire height, fire inclination angle, fire base width, view factor) of fires obtained by experimental burnings at field scale. The system consists of two synchronized and pre-calibrated multi-baseline stereo cameras operating in the visible spectrum. The cameras are positioned in the back and the lateral positions relatively to the direction of fire propagation. Algorithms have been developed in order to (i) register these cameras, (ii) model in three dimensions the fire front from the back stereoscopic images and (iii) estimate some geometrical properties of fire such as the inclination angle and the fire base width from the lateral stereoscopic images. A user graphical interface was developed as a practical tool to estimate fire propagation features and to display the obtained results. Fire spread experiments were conducted at field scale (about 20 m wide and 3 m high). The fuel consists of Mediterranean shrub vegetation. The obtained results are promising and show interesting performance achieved by the proposed system in operational and complex fire scenarios.

  11. Spacecraft Communications System Verification Using On-Axis Near Field Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Keating, Thomas; Baugh, Mark; Gosselin, R. B.; Lecha, Maria C.; Krebs, Carolyn A. (Technical Monitor)

    2000-01-01

    Determination of the readiness of a spacecraft for launch is a critical requirement. The final assembly of all subsystems must be verified. Testing of a communications system can mostly be done using closed-circuits (cabling to/from test ports), but the final connections to the antenna require radiation tests. The Tropical Rainfall Measuring Mission (TRMM) Project used a readily available 'near-fleld on-axis' equation to predict the values to be used for comparison with those obtained in a test program. Tests were performed in a 'clean room' environment at both Goddard Space Flight Center (GSFC) and in Japan at the Tanegashima Space Center (TnSC) launch facilities. Most of the measured values agreed with the predicted values to within 0.5 dB. This demonstrates that sometimes you can use relatively simple techniques to make antenna performance measurements when use of the 'far field ranges, anechoic chambers, or precision near-field ranges' are neither available nor practical. Test data and photographs are provided.

  12. Centaur liquid oxygen boost pump vibration test

    NASA Technical Reports Server (NTRS)

    Tang, H. M.

    1975-01-01

    The Centaur LOX boost pump was subjected to both the simulated Titan Centaur proof flight and confidence demonstration vibration test levels. For each test level, both sinusoidal and random vibration tests were conducted along each of the three orthogonal axes of the pump and turbine assembly. In addition to these tests, low frequency longitudinal vibration tests for both levels were conducted. All tests were successfully completed without damage to the boost pump.

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

    NASA Technical Reports Server (NTRS)

    Skoch, Gary J.

    1999-01-01

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

  14. Lorentz boost and non-Gaussianity in multifield DBI inflation

    SciTech Connect

    Mizuno, Shuntaro; Arroja, Frederico; Tanaka, Takahiro; Koyama, Kazuya

    2009-07-15

    We show that higher-order actions for cosmological perturbations in the multifield Dirac-Born-Infeld (DBI) inflation model are obtained by a Lorentz boost from the rest frame of the brane to the frame where the brane is moving. We confirm that this simple method provides the same third- and fourth-order actions at leading order in slow roll and in the small sound speed limit as those obtained by the usual Arnowitt-Deser-Misner formalism. As an application, we compute the leading order connected four-point function of the primordial curvature perturbation coming from the intrinsic fourth-order contact interaction in the multifield DBI-inflation model. At third order, the interaction Hamiltonian arises purely by the boost from the second-order action in the rest frame of the brane. The boost acts on the adiabatic and entropy modes in the same way, thus there exists a symmetry between the adiabatic and entropy modes. But at fourth order this symmetry is broken due to the intrinsic fourth-order action in the rest frame and the difference between the Lagrangian and the interaction Hamiltonian. Therefore, contrary to the three-point function, the momentum dependence of the purely adiabatic component and the components including the entropic contributions are different in the four-point function. This suggests that the trispectrum can distinguish the multifield DBI-inflation model from the single field DBI-inflation model.

  15. FULL ELECTROMAGNETIC FEL SIMULATION VIA THE LORENTZ-BOOSTED FRAME TRANSFORMATION

    SciTech Connect

    Fawley, William; Vay, Jean-Luc

    2010-08-16

    Numerical electromagnetic simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. A particularly good application for calculation in a boosted frame isthat of short wavelength free-electron lasers (FELs) where a high energy electron beam with small fractional energy spread interacts with a static magnetic undulator. In the optimal boost frame (i.e., the ponderomotive rest frame), the red-shifted FEL radiation and blue-shifted undulator field have identical wavelengths and the number of required longitudinal grid cells and time-steps for fully electromagnetic simulation (relative to the laboratory frame) decrease by factors of gamma^2 each. In theory, boosted frame EM codes permit direct study of FEL problems for which the eikonal approximation for propagation of the radiation field and wiggler-period-averaging for the particle-field interaction may be suspect. We have adapted the WARP code to apply this method to several electromagnetic FEL problems including spontaneous emission, strong exponential gain in a seeded, single pass amplifier configuration, and emission from e-beams in undulators with multiple harmonic components. WARP has a standard relativistic macroparticle mover and a fully 3-D electromagnetic field solver. We discuss our boosted frame results and compare with those obtained using the ?standard? eikonal FEL simulation approach.

  16. SU-E-T-515: Field-In-Field Compensation Technique Using Multi-Leaf Collimator to Deliver Total Body Irradiation (TBI) Dose

    SciTech Connect

    Lakeman, T; Wang, IZ

    2014-06-01

    Purpose: Total body irradiation (TBI) uses large parallel-opposed radiation fields to suppress the patient's immune system and eradicate the residual cancer cells in preparation of recipient for bone marrow transplant. The manual placement of lead compensators has been used conventionally to compensate for the varying thickness through the entire body in large-field TBI. The goal of this study is to pursue utilizing the modern field-in-field (FIF) technique with the multi-leaf collimator (MLC) to more accurately and efficiently deliver dose to patients in need of TBI. Method: Treatment plans utilizing the FIF technique to deliver a total body dose were created retrospectively for patients for whom CT data had been previously acquired. Treatment fields include one pair of opposed open large fields (collimator=45°) with a specific weighting and a succession of smaller fields (collimator=90°) each with their own weighting. The smaller fields are shaped by moving MLC to block the sections of the patient which have already received close to 100% of the prescribed dose. The weighting factors for each of these fields were calculated using the attenuation coefficient of the initial lead compensators and the separation of the patient in different positions in the axial plane. Results: Dose-volume histograms (DVH) were calculated for evaluating the FIF compensation technique. The maximum body doses calculated from the DVH were reduced from the non-compensated 179.3% to 148.2% in the FIF plans, indicating a more uniform dose with the FIF compensation. All calculated monitor units were well within clinically acceptable limits and exceeded those of the original lead compensation plan by less than 50 MU (only ~1.1% increase). Conclusion: MLC FIF technique for TBI will not significantly increase the beam on time while it can substantially reduce the compensator setup time and the potential risk of errors in manually placing lead compensators.

  17. Comparison of Phase-Based 3D Near-Field Source Localization Techniques for UHF RFID.

    PubMed

    Parr, Andreas; Miesen, Robert; Vossiek, Martin

    2016-01-01

    In this paper, we present multiple techniques for phase-based narrowband backscatter tag localization in three-dimensional space with planar antenna arrays or synthetic apertures. Beamformer and MUSIC localization algorithms, known from near-field source localization and direction-of-arrival estimation, are applied to the 3D backscatter scenario and their performance in terms of localization accuracy is evaluated. We discuss the impact of different transceiver modes known from the literature, which evaluate different send and receive antenna path combinations for a single localization, as in multiple input multiple output (MIMO) systems. Furthermore, we propose a new Singledimensional-MIMO (S-MIMO) transceiver mode, which is especially suited for use with mobile robot systems. Monte-Carlo simulations based on a realistic multipath error model ensure spatial correlation of the simulated signals, and serve to critically appraise the accuracies of the different localization approaches. A synthetic uniform rectangular array created by a robotic arm is used to evaluate selected localization techniques. We use an Ultra High Frequency (UHF) Radiofrequency Identification (RFID) setup to compare measurements with the theory and simulation. The results show how a mean localization accuracy of less than 30 cm can be reached in an indoor environment. Further simulations demonstrate how the distance between aperture and tag affects the localization accuracy and how the size and grid spacing of the rectangular array need to be adapted to improve the localization accuracy down to orders of magnitude in the centimeter range, and to maximize array efficiency in terms of localization accuracy per number of elements. PMID:27347976

  18. Evaluating climate field reconstruction techniques using improved emulations of real-world conditions

    NASA Astrophysics Data System (ADS)

    Wang, J.; Emile-Geay, J.; Guillot, D.; Smerdon, J. E.; Rajaratnam, B.

    2014-01-01

    Pseudoproxy experiments (PPEs) have become an important framework for evaluating paleoclimate reconstruction methods. Most existing PPE studies assume constant proxy availability through time and uniform proxy quality across the pseudoproxy network. Real multiproxy networks are, however, marked by pronounced disparities in proxy quality, and a steep decline in proxy availability back in time, either of which may have large effects on reconstruction skill. A suite of PPEs constructed from a millennium-length general circulation model (GCM) simulation is thus designed to mimic these various real-world characteristics. The new pseudoproxy network is used to evaluate four climate field reconstruction (CFR) techniques: truncated total least squares embedded within the regularized EM (expectation-maximization) algorithm (RegEM-TTLS), the Mann et al. (2009) implementation of RegEM-TTLS (M09), canonical correlation analysis (CCA), and Gaussian graphical models embedded within RegEM (GraphEM). Each method's risk properties are also assessed via a 100-member noise ensemble. Contrary to expectation, it is found that reconstruction skill does not vary monotonically with proxy availability, but also is a function of the type and amplitude of climate variability (forced events vs. internal variability). The use of realistic spatiotemporal pseudoproxy characteristics also exposes large inter-method differences. Despite the comparable fidelity in reconstructing the global mean temperature, spatial skill varies considerably between CFR techniques. Both GraphEM and CCA efficiently exploit teleconnections, and produce consistent reconstructions across the ensemble. RegEM-TTLS and M09 appear advantageous for reconstructions on highly noisy data, but are subject to larger stochastic variations across different realizations of pseudoproxy noise. Results collectively highlight the importance of designing realistic pseudoproxy networks and implementing multiple noise realizations of PPEs

  19. Comparison of Phase-Based 3D Near-Field Source Localization Techniques for UHF RFID

    PubMed Central

    Parr, Andreas; Miesen, Robert; Vossiek, Martin

    2016-01-01

    In this paper, we present multiple techniques for phase-based narrowband backscatter tag localization in three-dimensional space with planar antenna arrays or synthetic apertures. Beamformer and MUSIC localization algorithms, known from near-field source localization and direction-of-arrival estimation, are applied to the 3D backscatter scenario and their performance in terms of localization accuracy is evaluated. We discuss the impact of different transceiver modes known from the literature, which evaluate different send and receive antenna path combinations for a single localization, as in multiple input multiple output (MIMO) systems. Furthermore, we propose a new Singledimensional-MIMO (S-MIMO) transceiver mode, which is especially suited for use with mobile robot systems. Monte-Carlo simulations based on a realistic multipath error model ensure spatial correlation of the simulated signals, and serve to critically appraise the accuracies of the different localization approaches. A synthetic uniform rectangular array created by a robotic arm is used to evaluate selected localization techniques. We use an Ultra High Frequency (UHF) Radiofrequency Identification (RFID) setup to compare measurements with the theory and simulation. The results show how a mean localization accuracy of less than 30 cm can be reached in an indoor environment. Further simulations demonstrate how the distance between aperture and tag affects the localization accuracy and how the size and grid spacing of the rectangular array need to be adapted to improve the localization accuracy down to orders of magnitude in the centimeter range, and to maximize array efficiency in terms of localization accuracy per number of elements. PMID:27347976

  20. Study Of Optimal Reconstruction Techniques In The Field Of X-Ray Tomodensitometry Of The Heart

    NASA Astrophysics Data System (ADS)

    Wetta, P.; Peyrin, F.; Goutte, R.; Amiel, M.

    1983-08-01

    The computerized-aided tomodensitometry by X-rays is a powerful, precise and non invasive tool to investigate the human body as well as different objects and structures. The relatively long examination time, from 2 to 10 sec., which the present state of the art necessitates, limits the field of applications of this tool here to the static on quasistatic organs or objects (e.g. the brain or abdomen in medical diagnosis). When one try to reconstruct images of a dynamic object some errors or artefacts appear. In the case of the heart, in particular, the examination time takes several cardiac periods; so, the reconstructed image is highly blurred and for all purposes unusable. One solution, which can be used with a conventional scanner is the "gating" technique. Taking into account of the repetitive property of the cardiac movement, this technique necessitates to catch the projections in synchronization with the electrocardiogram. Thus a sub-program, controlled by the ECG sianal, has to select a set of projections corresponding to a certain time of the cardiac period. The implementation of this sub-program into the reconstruction code allows to obtain more sharp images of the heart at any given instant of the cardiac period. In this paper we discuss the methodology used to acquire the projections, the problems caused by the small number of projections, some mathematical solutions (extensions of signals and data, interpolations, uses of the redundancy in the information aiven by a FAN-BEAM system). These different possibilities are illustrated by some results we have obtained in our experiments on animals with a FAN-BEAM machine.

  1. In-Flight Technique for Acquiring Mid- And Far-Field Sonic Boom Signatures

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene G.; Baize, Daniel G.; Maglieri, Domenic, J.

    1999-01-01

    Flight test experiments have been conducted to establish the feasibility of obtaining sonic boom signature measurements below a supersonic aircraft using the NASA Portable Automatic Triggering System (PATS) mounted in the USMC Pioneer Unmanned Aerial Vehicle (UAV). This study forms a part of the NASA sonic boom minimization activities, specifically the demonstration of persistence of modified boom signatures to very large distances in a real atmosphere. The basic objective of the measurement effort was to obtain a qualitative view of the sonic boom signature in terms of its shape, number of shocks, their locations, and their relative strength. Results suggest that the technique may very well provide quantitative information relative to mid-field and far-field boom signatures. The purpose of this presentation is to describe the arrangement and operation of this in-flight system and to present the resulting sonic boom measurements. Adaption and modification of two PATS to the UAV payload section are described and include transducer location, mounting arrangement and recording system isolation. Ground static runup, takeoff and landing, and cruise flight checkouts regarding UAV propeller and flow noise on the PATS automated triggering system and recording mode are discussed. For the proof-of-concept tests, the PATS instrumented UAV was flown under radar control in steady-level flight at the altitude of 8700 feet MSL and at a cruise speed of about 60 knots. The USN F-4N sonic boom generating aircraft was vectored over the UAV on reciprocal headings at altitudes of about 1 1,000 feet MSL and 13,000 feet MSL at about Mach 1. 15. Sonic boom signatures were acquired on both PATS for all six supersonic passes. Although the UAV propeller noise is clearly evident in all the measurements, the F-4 boom signature is clearly distinguishable and is typically N-wave in character with sharply rising shock fronts and with a mid-shock associated with the inlet-wing juncture

  2. Statistical techniques for detecting the intergalactic magnetic field from large samples of extragalactic Faraday rotation data

    SciTech Connect

    Akahori, Takuya; Gaensler, B. M.; Ryu, Dongsu E-mail: bryan.gaensler@sydney.edu.au

    2014-08-01

    Rotation measure (RM) grids of extragalactic radio sources have been widely used for studying cosmic magnetism. However, their potential for exploring the intergalactic magnetic field (IGMF) in filaments of galaxies is unclear, since other Faraday-rotation media such as the radio source itself, intervening galaxies, and the interstellar medium of our Galaxy are all significant contributors. We study statistical techniques for discriminating the Faraday rotation of filaments from other sources of Faraday rotation in future large-scale surveys of radio polarization. We consider a 30° × 30° field of view toward the south Galactic pole, while varying the number of sources detected in both present and future observations. We select sources located at high redshifts and toward which depolarization and optical absorption systems are not observed so as to reduce the RM contributions from the sources and intervening galaxies. It is found that a high-pass filter can satisfactorily reduce the RM contribution from the Galaxy since the angular scale of this component toward high Galactic latitudes would be much larger than that expected for the IGMF. Present observations do not yet provide a sufficient source density to be able to estimate the RM of filaments. However, from the proposed approach with forthcoming surveys, we predict significant residuals of RM that should be ascribable to filaments. The predicted structure of the IGMF down to scales of 0.°1 should be observable with data from the Square Kilometre Array, if we achieve selections of sources toward which sightlines do not contain intervening galaxies and RM errors are less than a few rad m{sup –2}.

  3. TH-C-12A-03: Development of Expanded Field Irradiation Technique with Gimbaled X-Ray Head

    SciTech Connect

    Ono, T; Miyabe, Y; Yamada, M; Kaneko, S; Monzen, H; Mizowaki, T; Hiraoka, M; Sawada, A; Kokubo, M

    2014-06-15

    Purpose: The Vero4DRT has a maximum field size of 150×150 mm{sup 2}. The purposes of this study were to develop an expanded field irradiation technique using a unique gimbaled x-ray head of Vero4DRT and to evaluate its dosimetric characteristic. Methods: The expanded field irradiation consisted of four separate fields with 2.39 degree gimbal rotation around orthogonal two axes. The central beam axis for each field shifted 40 mm from the isocenter for longitudinal and lateral directions, and thus, the field size was expanded up to 230×230 mm{sup 2}. Adjacent region were created at the isocenter (center-adjacent expanded-field) and 20 mm from isocenter (offadjacent expanded-field). To create flat dose distribution in the combined piecewise-fields, the overlapping and gaps regions on the isocenter plane were adjusted with the gimbal rotating and the MLC. To evaluate dosimetric characteristic of the expanded-field, films inserted in water-equivalent phantoms at 50, 100 and 150 mm depth were irradiated and the field size, penumbra, flatness and symmetry were analyzed.In addition, the expandedfield irradiation technique was applied to IMRT. A head and neck IMRT field, which was planned for the conventional linac (Varian Clinac iX), was reproduced with the expanded-field of the Vero4DRT. The simulated dose distribution for the expanded IMRT field was compared to the measured dose distribution. Results: The field size, penumbra, flatness and symmetry of center- and off- adjacent expanded-fields were 230.2–232.1 mm, 7.8–10.7 mm, 2.3–6.5% and –0.5–0.4% at 100 mm depth. The 82.1% area of the expanded IMRT dose distribution was within 5% difference between measurement and simulation, which was analyzed upper 50% dose area, and the 3%/3 mm gamma pass rate was 98.4%. Conclusions: The expandedfield technique was developed using the gimbaled x-ray head. To extend applied targets, such as whole breast irradiations or head and neck IMRT, the expanded-field technique

  4. Integrating Novel Field, Laboratory and Modelling Techniques to Upscale Estimates of Soil Erosion

    NASA Astrophysics Data System (ADS)

    Wainwright, John; Parsons, Anthony; Cooper, James; Long, Edward; Hargrave, Graham; Kitchener, Ben; Hewett, Caspar; Onda, Yuichi; Furukawa, Tomomi; Obana, Eiichiro; Hayashi, Hirofumi; Noguchi, Takehiro

    2013-04-01

    Erosion is a particle-based phenomenon, yet most of current understanding and modelling of this process is based on bulk measurements rather than the movement of individual particles. Difficulties with measuring particle motions in dynamically changing conditions are being overcome with the application of two new technologies - particle imaging velocimetry (PIV) and radio frequency identification (RFID). It is thus possible to evaluate the entrainment, transport and deposition of individual particles and these data can be used to parameterize and to test particle-based modelling of the particle-based process. Both PIV and RFID tagging have been used in laboratory experiments to evaluate the detachment process by raindrops on bare surfaces and in shallow flows using rainfall simulation. The results suggest that the processes are more complex than hitherto thought with multiple detachment and transfer mechanisms. Because both mechanisms affect travel distance, they affect the ways in which estimates of soil erosion can be scaled from plot to hillslope and catchment scales. To evaluate movements at larger scales, we have also used RFID-tagged particles in field settings to look at sediment transfers following the Fukushima accident in Japan, 2011. A marker-in-cell model (MAHLERAN-MiC) has been developed to enable the laboratory results to be upscaled and tested in a field setting. Markers (representing sediment particles), containing sediment-property information, are initially distributed on a cellular grid. A cellular model is used to set up the boundary conditions and determine the hydrology and hydraulics on the hillslope. The markers are then moved through the grid according to these properties. This technique combines the advantages of Eulerian and Lagrangian methods while avoiding the shortcomings of each (computational efficiency vs. accuracy). The model simulates all the processes of detachment and transport; raindrop detachment and transport, interrill

  5. Assessment of function and quality of life in a phase II multi-institutional clinical trial of fractionated simultaneous in-field boost radiotherapy for patients with 1-3 metastases.

    PubMed

    Bauman, Glenn; Yartsev, Slav; Roberge, David; MacRae, Robert; Roa, Wilson; Panet-Raymond, Valerie; Masucci, Laura; Yaremko, Brian; D'Souza, David; Palma, David; Sexton, Tracy; Yu, Edward; Pantarotto, Jason R; Ahmad, Belal; Fisher, Barbara; Dar, A Rashid; Lambert, Carole; Pond, Gregory; Stitt, Larry; Tay, Keng Yeow; Rodrigues, George

    2016-07-01

    We examined functional outcomes and quality of life of whole brain radiotherapy (WBRT) with integrated fractionated stereotactic radiotherapy boost (FSRT) for brain metastases treatment. Eighty seven people with 1-3 brain metastases (54/87 lung primary, 42/87 single brain metastases) were enrolled on this Phase II trial of WBRT (30 Gy/10) + simultaneous FSRT, (60 Gy/10). Median overall follow-up and survival was 5.4 months, 6 month actuarial intra-lesional control was 78 %; only 1 patient exhibited grade 4 toxicity (worsened seizures); most treatment related toxicity was grade 1 or 2; 2/87 patients demonstrated asymptomatic radiation necrosis on follow-up imaging. Mean (Min-Max) baseline KPS, Mini Mental Status Exam (MMSE) and FACT-BR quality of life were 83 (70-100), 28 (21-30) and 143 (98-153). Lower baseline MMSE (but not KPS or FACT-Br) was associated with worse survival after adjusting for age, number of metastases, primary and extra-cranial disease status. Crude rates of deterioration (>10 points decrease from baseline for KPS and FACT-Br, MMSE fall to <27) ranged from 26 to 38 % for KPS, 32-59 % for FACT-Br and 0-16 % for MMSE depending on the time-point assessed with higher rates generally noted at earlier time points (≤6 months post-treatment). Using a linear mixed models analysis, significant declines from baseline were noted for KPS and FACT-Br (largest effects at 6 weeks to 3 months) with no significant change in MMSE. The effects on function and quality of life of this integrated treatment of WBRT + simultaneous FSRT were similar to other published series combining WBRT + radiosurgery. PMID:27084705

  6. Subdivision based isogeometric analysis technique for electric field integral equations for simply connected structures

    NASA Astrophysics Data System (ADS)

    Li, Jie; Dault, Daniel; Liu, Beibei; Tong, Yiying; Shanker, Balasubramaniam

    2016-08-01

    The analysis of electromagnetic scattering has long been performed on a discrete representation of the geometry. This representation is typically continuous but not differentiable. The need to define physical quantities on this geometric representation has led to development of sets of basis functions that need to satisfy constraints at the boundaries of the elements/tessellations (viz., continuity of normal or tangential components across element boundaries). For electromagnetics, these result in either curl/div-conforming basis sets. The geometric representation used for analysis is in stark contrast with that used for design, wherein the surface representation is higher order differentiable. Using this representation for both geometry and physics on geometry has several advantages, and is elucidated in Hughes et al. (2005) [7]. Until now, a bulk of the literature on isogeometric methods have been limited to solid mechanics, with some effort to create NURBS based basis functions for electromagnetic analysis. In this paper, we present the first complete isogeometry solution methodology for the electric field integral equation as applied to simply connected structures. This paper systematically proceeds through surface representation using subdivision, definition of vector basis functions on this surface, to fidelity in the solution of integral equations. We also present techniques to stabilize the solution at low frequencies, and impose a Calderón preconditioner. Several results presented serve to validate the proposed approach as well as demonstrate some of its capabilities.

  7. Quantum-field-theoretical approach to phase-space techniques: Generalizing the positive-P representation

    SciTech Connect

    Plimak, L.I.; Fleischhauer, M.; Olsen, M.K.; Collett, M.J.

    2003-01-01

    We present an introduction to phase-space techniques (PST) based on a quantum-field-theoretical (QFT) approach. In addition to bridging the gap between PST and QFT, our approach results in a number of generalizations of the PST. First, for problems where the usual PST do not result in a genuine Fokker-Planck equation (even after phase-space doubling) and hence fail to produce a stochastic differential equation (SDE), we show how the system in question may be approximated via stochastic difference equations (S{delta}E). Second, we show that introducing sources into the SDE's (or S{delta}E's) generalizes them to a full quantum nonlinear stochastic response problem (thus generalizing Kubo's linear reaction theory to a quantum nonlinear stochastic response theory). Third, we establish general relations linking quantum response properties of the system in question to averages of operator products ordered in a way different from time normal. This extends PST to a much wider assemblage of operator products than are usually considered in phase-space approaches. In all cases, our approach yields a very simple and straightforward way of deriving stochastic equations in phase space.

  8. A TECHNIQUE FOR PRIMARY BEAM CALIBRATION OF DRIFT-SCANNING, WIDE-FIELD ANTENNA ELEMENTS

    SciTech Connect

    Pober, Jonathan C.; Parsons, Aaron R.; Jacobs, Daniel C.; Aguirre, James E.; Moore, David F.; Bradley, Richard F.; Parashare, Chaitali R.; Carilli, Chris L.; Gugliucci, Nicole E.

    2012-02-15

    We present a new technique for calibrating the primary beam of a wide-field, drift-scanning antenna element. Drift-scan observing is not compatible with standard beam calibration routines, and the situation is further complicated by difficult-to-parameterize beam shapes and, at low frequencies, the sparsity of accurate source spectra to use as calibrators. We overcome these challenges by building up an interrelated network of source 'crossing points'-locations where the primary beam is sampled by multiple sources. Using the single assumption that a beam has 180 Degree-Sign rotational symmetry, we can achieve significant beam coverage with only a few tens of sources. The resulting network of crossing points allows us to solve for both a beam model and source flux densities referenced to a single calibrator source, circumventing the need for a large sample of well-characterized calibrators. We illustrate the method with actual and simulated observations from the Precision Array for Probing the Epoch of Reionization.

  9. Time scaling with efficient time-propagation techniques for atoms and molecules in pulsed radiation fields

    SciTech Connect

    Hamido, Aliou; Frapiccini, Ana Laura; Piraux, Bernard; Eiglsperger, Johannes; Madronero, Javier; Mota-Furtado, Francisca; O'Mahony, Patrick

    2011-07-15

    We present an ab initio approach to solving the time-dependent Schroedinger equation to treat electron- and photon-impact multiple ionization of atoms or molecules. It combines the already known time-scaled coordinate method with a high-order time propagator based on a predictor-corrector scheme. In order to exploit in an optimal way the main advantage of the time-scaled coordinate method, namely, that the scaled wave packet stays confined and evolves smoothly toward a stationary state, of which the squared modulus is directly proportional to the electron energy spectra in each ionization channel, we show that the scaled bound states should be subtracted from the total scaled wave packet. In addition, our detailed investigations suggest that multiresolution techniques like, for instance, wavelets are the most appropriate ones to represent the scaled wave packet spatially. The approach is illustrated in the case of the interaction of a one-dimensional model atom as well as atomic hydrogen with a strong oscillating field.

  10. Application of near-field microwave sensing techniques for segregation detection in concrete members

    NASA Astrophysics Data System (ADS)

    Bois, K. J.; Benally, A. D.; Zoughi, R.; Nowak, P. S.

    2000-05-01

    In this presentation, a simple, low-cost near-field microwave nondestructive inspection technique for segregation detection in concrete members is presented. This process employs information from the measured magnitude of reflection coefficient at the aperture of an open-ended rectangular waveguide sensor. These measurements, whose results will be presented, were conducted using a Hewlett-Packard HP8510B network analyzer. However, in practice a simple and relatively inexpensive inspection apparatus constructed from discrete microwave components can easily be employed. It is shown that the standard deviation of magnitude of reflection coefficient measurement is linearly correlated with the aggregate density in concrete. Furthermore, for concrete in which the aggregate has segregated, this measurable parameter will change as a function of vertical position of the microwave scan. Results correlating the microwave measurements to the actual aggregate density of a well consolidated concrete specimen and a specimen in which the aggregate has segregated will be presented. Finally, the simple and low cost application of this method for in situ detection of aggregate segregation in concrete structures will be discussed.

  11. Remote field eddy current technique applied to the inspection of nonmagnetic steam generator tubes

    NASA Astrophysics Data System (ADS)

    Shin, Young-Kil; Chung, Tae-Eon; Lord, William

    2001-04-01

    As steam generator (SG) tubes have aged, new and subtle degradations have appeared. Most of them start growing from outside the tubes. Since outer diameter defects might not be detected by conventional eddy current testing due to skin effect phenomena, this paper studies the feasibility of using the remote field eddy current (RFEC) technique, which has shown equal sensitivity to inner diameter (ID) and outer diameter (OD) defects in ferromagnetic pipe inspection. Finite element modeling studies show that the operating frequency needs to be increased up to a few hundred kHz in order for RFEC effects to occur in the nonmagnetic SG tube. The proper distance between exciter and sensor coils is also found to be 1.5 OD, which is half of the distance used in ferromagnetic pipe inspection. The resulting defect signals show equal sensitivity to ID and OD defects. These results demonstrate superior capability of the proposed RFEC probe compared to the differential ECT probe in detecting OD defects.

  12. A Physics-based Automated Technique for the Detection of Field Line Resonance Frequency in Ground Magnetometer Data

    NASA Astrophysics Data System (ADS)

    Boudouridis, A.; Zesta, E.; Moldwin, M.

    2015-12-01

    The accurate determination of the Field Line Resonance (FLR) frequency of a resonating geomagnetic field line is necessary for the remote monitoring of the plasmaspheric mass density during geomagnetic storms and quiet times alike. Under certain assumptions the plasmaspheric mass density at the equator is inversely proportional to the square of the FLR frequency. The most common techniques to determine the FLR frequency from ground magnetometer measurements are the amplitude ratio and phase difference techniques, both based on geomagnetic field measurements at two latitudinally separated ground stations. Previously developed automated techniques have used statistical methods to pinpoint the FLR frequency using the amplitude ratio and phase difference calculations. We now introduce a physics-based automated technique that can reproduce the resonant wave characteristics from the two ground station data, and from those determine the FLR frequency. The advantage of the new technique, besides moving away from ambiguous statistical manipulations of the ground data, is the estimation of physically determined errors of the FLR frequency, which can yield physically determined errors of the equatorial plasmaspheric mass density. We present preliminary results of the new technique calculations, and test it using data from the new Inner-Magnetospheric Array for Geospace Science (iMAGS) ground magnetometer chain along the coast of Chile and the east coast of the United States. We compare the results with the results of previously published statistical automated techniques.

  13. A framework for validating light fields created using physically based rendering techniques

    NASA Astrophysics Data System (ADS)

    Whittinghill, David M.

    This research study presents a framework for applying physically based global illumination techniques to the creation of software models of light fields that are then validated against actual light fields measured in physical experiments. A prior experiment was performed by horticulture scientists in which the light field of an empty plant growth chamber was measured using quantum sensors at fixed spatial intervals. The result was a light map consisting of a 9 x 45, fixed-width, two-dimensional graph of sensor readings that described the intensity of radiant energy present in the chamber at the chosen locations. A single observation of the growth chamber was made resulting in a single data set consisting of 45 different, location-sensitive irradiance observations. To test this framework a series of simulations were performed in which the physical attributes of the growth chamber were duplicated as closely as possible in a virtual growth chamber software model. Modeled attributes included physical dimensions, wall and light reflectivity, and full-spectrum light characterization. Light transport was modeled using a physically based, global illumination rendering technique called photon mapping. Virtual sensors that recorded the intensity of the light that transmitted through their surface were placed in the virtual chamber at the same position and interval as the ones that were used in the physical experiment. The output of the virtual chamber experiments were represented as a graph in the same configuration as the one in the physical experiment. The experiment was conducted using a modified version of pbrt, a physically based, extensible renderer developed by Matt Pharr and Greg Humphreys [1]. As photon mapping uses a stochastic algorithm, many repetitions of the virtual chamber experiment were performed and the mean and standard deviation were recorded as a global measure for each chamber as well as for each individual sensor location. The global means of the

  14. Boosting Big National Lab Data

    SciTech Connect

    Kleese van Dam, Kerstin

    2013-02-21

    Introduction: Big data. Love it or hate it, solving the world’s most intractable problems requires the ability to make sense of huge and complex sets of data and do it quickly. Speeding up the process – from hours to minutes or from weeks to days – is key to our success. One major source of such big data are physical experiments. As many will know, these physical experiments are commonly used to solve challenges in fields such as energy security, manufacturing, medicine, pharmacology, environmental protection and national security. Experiments use different instruments and sensor types to research for example the validity of new drugs, the base cause for diseases, more efficient energy sources, new materials for every day goods, effective methods for environmental cleanup, the optimal ingredients composition for chocolate or determine how to preserve valuable antics. This is done by experimentally determining the structure, properties and processes that govern biological systems, chemical processes and materials. The speed and quality at which we can acquire new insights from experiments directly influences the rate of scientific progress, industrial innovation and competitiveness. And gaining new groundbreaking insights, faster, is key to the economic success of our nations. Recent years have seen incredible advances in sensor technologies, from house size detector systems in large experiments such as the Large Hadron Collider and the ‘Eye of Gaia’ billion pixel camera detector to high throughput genome sequencing. These developments have led to an exponential increase in data volumes, rates and variety produced by instruments used for experimental work. This increase is coinciding with a need to analyze the experimental results at the time they are collected. This speed is required to optimize the data taking and quality, and also to enable new adaptive experiments, where the sample is manipulated as it is observed, e.g. a substance is injected into a

  15. Evaluating climate field reconstruction techniques using improved emulations of real-world conditions

    NASA Astrophysics Data System (ADS)

    Wang, J.; Emile-Geay, J.; Guillot, D.; Smerdon, J. E.; Rajaratnam, B.

    2013-06-01

    Pseudoproxy experiments (PPEs) have become an essential framework for evaluating paleoclimate reconstruction methods. Most existing PPE studies assume constant proxy availability through time and uniform proxy quality across the pseudoproxy network. Real multi-proxy networks are, however, marked by pronounced disparities in proxy quality, and a steep decline in proxy availability back in time, either of which may have large effects on reconstruction skill. Additionally, an investigation of a real-world global multi-proxy network suggests that proxies are not exclusively indicators of local climate; rather, many are indicative of large-scale teleconnections. A suite of PPEs constructed from a millennium-length general circulation model simulation is thus designed to mimic these various real-world characteristics. The new pseudoproxy network is used to evaluate four climate field reconstruction (CFR) techniques: truncated total least square embedded within the regularized EM algorithm (RegEM-TTLS), the Mann et al. (2009) implementation of RegEM-TTLS (M09), canonical correlation analysis (CCA), and Gaussian graphical models embedded within RegEM (GraphEM). Each method's risk properties are also assessed via a 100-member noise ensemble. Contrary to expectation, it is found that reconstruction skill does not vary monotonically with proxy availability, but rather is a function of the type of climate variability (forced events vs. internal variability). The use of realistic spatiotemporal pseudoproxy characteristics also exposes large inter-method differences. Despite the comparable fidelity in reconstructing the global mean temperature, spatial skill varies considerably between CFR techniques. Both GraphEM and CCA efficiently exploit teleconnections, and produce consistent reconstructions across the ensemble. RegEM-TTLS and M09 appear advantageous for reconstructions on highly noisy data, but are subject to larger stochastic variations across different realizations of

  16. Centrifugal compressor design for electrically assisted boost

    NASA Astrophysics Data System (ADS)

    Y Yang, M.; Martinez-Botas, R. F.; Zhuge, W. L.; Qureshi, U.; Richards, B.

    2013-12-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically.

  17. Tsunakawa-Shaw method - an absolute paleointensity technique using alternating field demagnetization

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Mochizuki, N.; Shibuya, H.; Tsunakawa, H.

    2015-12-01

    Among geologic materials volcanic rocks have been typically used to deduce an absolute paleointensity. In the last decade, however, there seems a becoming consensus that volcanic rocks are not so ideal materials due to such as magnetic grains other than non-interacting single domain particles. One approach to obtain a good paleointensity estimate from the rocks is to reduce and correct the non-ideality, suppress alterations in laboratory and screen out suspicious results. We have been working on a development and an application of the Tsunakawa-Shaw method, which has been previously called the LTD-DHT Shaw method. This method is an AF(alternating field)-based technique and thus a paleointensity is estimated using coercivity spectra. To reduce the non-ideality, all remanences undergo low-temperature demagnetization (LTD) before any AF demagnetizations to remove multi-domain like component. To correct the non-ideality, anhysteretic remanent magnetizations (ARMs) are imparted with their directions parallel to natural remanent magnetizations and laboratory-imparted thermoremanent magnetizations (TRMs) and measured before and after laboratory heating. These ARMs are used to correct remanence anisotropies, possible interaction effects originated from the non-ideal grains and TRM changes caused by laboratory alterations. TRMs are imparted by heating specimens above their Curie temperatures and then cooling to room temperature at once to simulate nature conditions. These cycles are done in vacuum to suppress alterations in laboratory. Obtained results are judged by selection criteria, including a check for validity of the ARM corrections.It has been demonstrated that successful paleointensities are obtained from historical lavas in Japan and Hawaii, and from baked clay samples from a reconstructed ancient kiln, with the flow-mean precision of 5-10%. In case of old volcanic rocks, however, the method does not necessarily seem to be perfect. We will summarize these points in

  18. Field testing of fugitive dust control techniques at a uranium mill tailings pile - 1982 Field Test, Gas Hills, Wyoming.

    SciTech Connect

    Elmore, M.R.; Hartley, J.N.

    1983-12-01

    A field test was conducted on a uranium tailings pile to evaluate the effectiveness of 15 chemical stabilizers for control of fugitive dust from uranium mill tailings. A tailings pile at the Federal American Partners (FAP) Uranium Mill, Gas Hills, Wyoming, was used for the field test. Preliminary laboratory tests using a wing tunnel were conducted to select the more promising stabilizers for field testing. Fourteen of the chemical stabilizers were applied with a field spray system pulled behind a tractor; one--Hydro Mulch--was applied with a hydroseeder. A portable weather station and data logger were installed to record the weather conditions at the test site. After 1 year of monitoring (including three site visits), all of the stabilizers have degraded to some degree; but those applied at the manufacturers' recommended rate are still somewhat effective in reducing fugitive emissions. The following synthetic polymer emulsions appear to be the more effective stabilizers: Wallpol 40-133 from Reichold Chemicals, SP-400 from Johnson and March Corporation, and CPB-12 from Wen Don Corporation. Installed costs for the test plots ranged from $8400 to $11,300/ha; this range results from differences in stabilizer costs. Large-scale stabilization costs of the test materials are expected to range from $680 to $3600/ha based on FAP experience. Evaluation of the chemical stabilizers will continue for approximately 1 year. 2 references, 33 figures, 22 tables.

  19. Increased Oil Production and Reserves from Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah, Class I

    SciTech Connect

    Morgan, Craig D.; Gwynn, Wallace; Deo, Milind D.; Jarrard, Richard; Curtice, Richard; Morris, Thomas H.; Smouse, DeForrest; Tripp, Carol N.

    2000-01-20

    The objective of this project was to increase oil production and reserves by the use of improved reservoir characterization and completion techniques in the Unita Basin Utah. To accomplish this objective, a two-year geologic and engineering characterization of the Bluebell field was conducted. The study evaluated surface and subsurface data, currently used completion techniques, and common production problems. It was determined that advanced case- and open-hole logs could be effective in determining productive beds and that staged-interval (about 500 ft [150 m] per stage) and bed-scale isolation completion techniques could result in improved well performance.

  20. Application of the planar-scanning technique to the near-field dosimetry of millimeter-wave radiators.

    PubMed

    Zhao, Jianxun; Lu, Hongmin; Deng, Jun

    2015-02-01

    The planar-scanning technique was applied to the experimental measurement of the electric field and power flux density (PFD) in the exposure area close to the millimeter-wave (MMW) radiator. In the near-field region, the field and PFD were calculated from the plane-wave spectrum of the field sampled on a scan plane far from the radiator. The measurement resolution was improved by reducing the spatial interval between the field samples to a fraction of half the wavelength and implementing multiple iterations of the fast Fourier transform. With the reference to the results from the numerical calculation, an experimental evaluation of the planar-scanning measurement was made for a 50 GHz radiator. Placing the probe 1 to 3 wavelengths from the aperture of the radiator, the direct measurement gave the near-field data with significant differences from the numerical results. The planar-scanning measurement placed the probe 9 wavelengths away from the aperture and effectively reduced the maximum and averaged differences in the near-field data by 70.6% and 65.5%, respectively. Applied to the dosimetry of an open-ended waveguide and a choke ring antenna for 60 GHz exposure, the technique proved useful to the measurement of the PFD in the near-field exposure area of MMW radiators. PMID:25644219

  1. Conformal Locoregional Breast Irradiation with an Oblique Parasternal Photon Field Technique

    SciTech Connect

    Erven, Katrien; Petillion, Saskia; Weltens, Caroline; Van den Heuvel, Frank; Defraene, Gilles; Van Limbergen, Erik; Van den Bogaert, Walter

    2011-04-01

    We evaluated an isocentric technique for conformal irradiation of the breast, internal mammary, and medial supra-clavicular lymph nodes (IM-MS LN) using the oblique parasternal photon (OPP) technique. For 20 breast cancer patients, the OPP technique was compared with a conventional mixed-beam technique (2D) and a conformal partly wide tangential (PWT) technique, using dose-volume histogram analysis and normal tissue complication probabilities (NTCPs). The 3D techniques resulted in a better target coverage and homogeneity than did the 2D technique. The homogeneity index for the IM-MS PTV increased from 0.57 for 2D to 0.90 for PWT and 0.91 for OPP (both p < 0.001). The OPP technique was able to reduce the volume of heart receiving more than 30 Gy (V{sub 30}), the cardiac NTCP, and the volume of contralateral breast receiving 5 Gy (V{sub 5}) compared with the PWT plans (all p < 0.05). There is no significant difference in mean lung dose or lung NTCP between both 3D techniques. Compared with the PWT technique, the volume of lung receiving more than 20 Gy (V{sub 20}) was increased with the OPP technique, whereas the volume of lung receiving more than 40 Gy (V{sub 40}) was decreased (both p < 0.05). Compared with the PWT technique, the OPP technique can reduce doses to the contralateral breast and heart at the expense of an increased lung V{sub 20}.

  2. Development of novel techniques to study the magnetic field evolution in wire array Z-pinches and X pinches

    NASA Astrophysics Data System (ADS)

    Syed, Wasif

    Understanding the magnetic field topology in wire-array Z-pinches is of great significance for their ultimate application to stockpile stewardship and inertial confinement fusion. We have developed and tested several novel techniques involving material-based sensors to measure magnetic fields as a function of space and time in high energy density plasmas on pulsed power machines. We first briefly introduce a technique that was used to measure a lower limit of the maximum magnetic field of a sub-microsecond duration pulse using magnetic reversal in CoPt thin films. The time-varying magnetic field was generated by an exploding wire array plasma called an X pinch produced on the 0.5 MA, 100 ns pulse duration, XP pulsed power generator. We then introduce a technique based on Faraday rotation that was used to measure magnetic fields in wire-array Z-pinches produced on the 1 MA, 100 ns rise time, COBRA pulsed power generator as well as on the XP generator. This technique measures magnetic fields as a function of space and time using Faraday rotation of a single longitudinal mode (SLM) laser through a magneto-optically active bulk waveguide, multicomponent terbium borate glass, placed adjacent to, or within, the wire array. We have measured fields > 10 T with 100 ns rise times outside of a wire-array Z-pinch for the entire duration (˜250 ns) of the current pulse and as much as ˜2 T inside a wire-array for ˜40 ns from the start of current. This is the first time that such rapidly varying and large fields have been measured using the terbium borate glass. The third method, also based on Faraday rotation of SLM laser light utilized an integrated optical fiber sensor (a fiber-sensor-fiber assembly) on the XP pulsed power generator that also yielded a measurement of the magnetic field of a wire-array Z-pinch for part of the current pulse. Finally, we repeated the third method by fabricating a "thin film waveguide" of terbium borate glass to increase the spatial resolution

  3. A BOOST FOR THE CLASSICS.

    ERIC Educational Resources Information Center

    FORBES, MARGARET

    THE ARTS AND HUMANITIES INSTITUTE FOR LATIN TEACHERS EMPHASIZED TEACHING TECHNIQUES, INSTRUCTIONAL MATERIALS FOR BEGINNING (SEVENTH-GRADE) LATIN CLASSES, AND IMPROVEMENT OF TEACHER PROFICIENCY IN LANGUAGE SKILLS. THE PARTICIPANTS CONSIDERED THE CONCURRENT APPROACH AND USE OF VISUAL, AURAL, PICTORIAL, AND KINETIC METHODS OF LANGUAGE INSTRUCTION.…

  4. Dosimetric Comparison of Split Field and Fixed Jaw Techniques for Large IMRT Target Volumes in the Head and Neck

    SciTech Connect

    Srivastava, Shiv P.; Das, Indra J.; Kumar, Arvind; Johnstone, Peter A.S.

    2011-04-01

    Some treatment planning systems (TPSs), when used for large-field (>14 cm) intensity-modulated radiation therapy (IMRT), create split fields that produce excessive multiple-leaf collimator segments, match-line dose inhomogeneity, and higher treatment times than nonsplit fields. A new method using a fixed-jaw technique (FJT) forces the jaw to stay at a fixed position during optimization and is proposed to reduce problems associated with split fields. Dosimetric comparisons between split-field technique (SFT) and FJT used for IMRT treatment is presented. Five patients with head and neck malignancies and regional target volumes were studied and compared with both techniques. Treatment planning was performed on an Eclipse TPS using beam data generated for Varian 2100C linear accelerator. A standard beam arrangement consisting of nine coplanar fields, equally spaced, was used in both techniques. Institutional dose-volume constraints used in head and neck cancer were kept the same for both techniques. The dosimetric coverage for the target volumes between SFT and FJT for head and neck IMRT plan is identical within {+-}1% up to 90% dose. Similarly, the organs at risk (OARs) have dose-volume coverage nearly identical for all patients. When the total monitor unit (MU) and segments were analyzed, SFT produces statistically significant higher segments (17.3 {+-} 6.3%) and higher MU (13.7 {+-} 4.4%) than the FJT. There is no match line in FJT and hence dose uniformity in the target volume is superior to the SFT. Dosimetrically, SFT and FJT are similar for dose-volume coverage; however, the FJT method provides better logistics, lower MU, shorter treatment time, and better dose uniformity. The number of segments and MU also has been correlated with the whole body radiation dose with long-term complications. Thus, FJT should be the preferred option over SFT for large target volumes.

  5. Physics Laboratory Investigation of Vocational High School Field Stone and Concrete Construction Techniques in the Central Java Province (Indonesia)

    ERIC Educational Resources Information Center

    Purwandari, Ristiana Dyah

    2015-01-01

    The investigation aims in this study were to uncover the observations of infrastructures and physics laboratory in vocational high school for Stone and Concrete Construction Techniques Expertise Field or Teknik Konstruksi Batu dan Beton (TKBB)'s in Purwokerto Central Java Province, mapping the Vocational High School or Sekolah Menengah Kejuruan…

  6. Boosted and Linked Mixtures of HMMs for Brain-Machine Interfaces

    NASA Astrophysics Data System (ADS)

    Darmanjian, Shalom; Principe, Jose C.

    2008-12-01

    We propose two algorithms that decompose the joint likelihood of observing multidimensional neural input data into marginal likelihoods. The first algorithm, boosted mixtures of hidden Markov chains (BMs-HMM), applies techniques from boosting to create implicit hierarchic dependencies between these marginal subspaces. The second algorithm, linked mixtures of hidden Markov chains (LMs-HMM), uses a graphical modeling framework to explicitly create the hierarchic dependencies between these marginal subspaces. Our results show that these algorithms are very simple to train and computationally efficient, while also reducing the input dimensionality for brain-machine interfaces (BMIs).

  7. Fusing Observations and Model Results for Creation of Enhanced Ozone Spatial Fields: Comparison of Three Techniques

    EPA Science Inventory

    This paper presents three simple techniques for fusing observations and numerical model predictions. The techniques rely on model/observation bias being considered either as error free, or containing some uncertainty, the latter mitigated with a Kalman filter approach or a spati...

  8. Performance of marking techniques in the field and laboratory for Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A reliable marking technique was needed for a mark-release-recapture experiment with adults of Diabrotica speciosa (Germar). Four marking techniques, acrylic paint (spattered or brushed on the surface of the insect); and fluorescent pigments (dusted on surfaces or mixed with diet to produce an inges...

  9. Music Might Give Babies' Language Skills a Boost

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158486.html Music Might Give Babies' Language Skills a Boost Small ... April 25, 2016 (HealthDay News) -- Can listening to music boost your baby's brainpower? Maybe, at least in ...

  10. Music Might Give Babies' Language Skills a Boost

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_158486.html Music Might Give Babies' Language Skills a Boost Small ... April 25, 2016 (HealthDay News) -- Can listening to music boost your baby's brainpower? Maybe, at least in ...

  11. A mountain watershed hydrology field course: Experiential learning in hydrologic concepts and measurement techniques

    NASA Astrophysics Data System (ADS)

    Hogue, T. S.; Kinoshita, A. M.; Randell, J.

    2013-12-01

    A field mountainshed hydrology course was offered annually since April 2006 to investigate and quantify hydrologic processes in the Sagehen experimental watershed in the Sierra Nevada, California. This advanced field-based course was offered through the University of California, Los Angeles (UCLA) Civil and Environmental Engineering (CEE) and was primarily for upper division undergraduate students in the hydrology emphasis track. This unique ten-week course focused on the study of catchment processes in snow-dominated and mountainous regions. The course offered a range of activities, including quantifying distributed watershed fluxes, investigating geochemical properties of surface and groundwater systems, measuring channel dynamics and stream morphology, and analysis of snowpack properties. A major component of the course included an extended field trip to Sagehen where students undertook a range of observations and field experiments. Pre-field trip coursework required an in-depth analysis of historical streamflow, precipitation, snow and other regional hydroclimatological data. At Sagehen, students worked together in teams while gaining a range of field experiences. Post-field trip labs included analysis of their collected field data and comparison to previous years' data, culminating in a comprehensive final report and shared with the Sagehen Creek Field Station as part of a cooperative effort. This presentation will highlight course, laboratory and field design, a compilation of observational results, and insight on lessons learned through the course history.

  12. Large-timestep techniques for particle-in-cell simulation of systems with applied fields that vary rapidly in space

    SciTech Connect

    Friedman, A.; Grote, D.P.

    1996-10-01

    Under conditions which arise commonly in space-charge-dominated beam applications, the applied focusing, bending, and accelerating fields vary rapidly with axial position, while the self-fields (which are, on average, comparable in strength to the applied fields) vary smoothly. In such cases it is desirable to employ timesteps which advance the particles over distances greater than the characteristic scales over which the applied fields vary. Several related concepts are potentially applicable: sub-cycling of the particle advance relative to the field solution, a higher-order time-advance algorithm, force-averaging by integration along approximate orbits, and orbit-averaging. We report on our investigations into the utility of such techniques for systems typical of those encountered in accelerator studies for heavy-ion beam-driven inertial fusion.

  13. Boost symmetry in the Quantum Gravity sector

    SciTech Connect

    Cianfrani, Francesco; Montani, Giovanni

    2008-01-03

    We perform a canonical quantization of gravity in a second-order formulation, taking as configuration variables those describing a 4-bein, not adapted to the space-time splitting. We outline how, neither if we fix the Lorentz frame before quantizing, nor if we perform no gauge fixing at all, is invariance under boost transformations affected by the quantization.

  14. The Attentional Boost Effect with Verbal Materials

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Spataro, Pietro; Picklesimer, Milton

    2014-01-01

    Study stimuli presented at the same time as unrelated targets in a detection task are better remembered than stimuli presented with distractors. This attentional boost effect (ABE) has been found with pictorial (Swallow & Jiang, 2010) and more recently verbal materials (Spataro, Mulligan, & Rossi-Arnaud, 2013). The present experiments…

  15. Cleanouts boost Devonian shale gas flow

    SciTech Connect

    Not Available

    1991-02-04

    Cleaning shale debris from the well bores is an effective way to boost flow rates from old open hole Devonian shale gas wells, research on six West Virginia wells begun in 1985 has shown. Officials involved with the study say the Appalachian basin could see 20 year recoverable gas reserves hiked by 315 bcf if the process is used on a wide scale.

  16. Schools Enlisting Defense Industry to Boost STEM

    ERIC Educational Resources Information Center

    Trotter, Andrew

    2008-01-01

    Defense contractors Northrop Grumman Corp. and Lockheed Martin Corp. are joining forces in an innovative partnership to develop high-tech simulations to boost STEM--or science, technology, engineering, and mathematics--education in the Baltimore County schools. The Baltimore County partnership includes the local operations of two major military…

  17. The Attentional Boost Effect and Context Memory

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Smith, S. Adam; Spataro, Pietro

    2016-01-01

    Stimuli co-occurring with targets in a detection task are better remembered than stimuli co-occurring with distractors--the attentional boost effect (ABE). The ABE is of interest because it is an exception to the usual finding that divided attention during encoding impairs memory. The effect has been demonstrated in tests of item memory but it is…

  18. Weight-Loss Surgery May Boost Survival

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159166.html Weight-Loss Surgery May Boost Survival Overall death risk dropped ... 3, 2016 THURSDAY, June 2, 2016 (HealthDay News) -- Weight-loss surgery might significantly lower obese people's risk of ...

  19. Committee approves bill to boost NIH funding.

    PubMed

    2015-08-01

    A U.S. House of Representatives committee approved the 21st Century Cures Act. If passed by Congress, the bill would boost funding for the NIH and FDA and introduce new strategies for accelerating the approval of drugs and devices. PMID:26116105

  20. Wide-field optical coherence tomography angiography using extended field imaging technique to evaluate the nonperfusion area in retinal vein occlusion

    PubMed Central

    Kimura, Masayo; Nozaki, Miho; Yoshida, Munenori; Ogura, Yuichiro

    2016-01-01

    Purpose Optical coherence tomography angiography (OCTA) is a newly developed technology which allows us to reconstruct the three-dimensional chorioretinal vasculature without dye injection. OCTA is a noninvasive, rapid, and reproducible method to assess retinal ischemia. However, one of its limitations is the size of scanning area. A novel yet simple technique to expand the scan length on optical coherence tomography has been reported as an extended field imaging (EFI) technique. It involves imaging the posterior pole through trial frames fitted with a +20 diopter lens. We applied this technique to OCTA to evaluate retinal vein occlusion. Materials and methods Ten eyes of nine patients with retinal vein occlusion were studied. The average age was 69.0 years (range: 49–93 years). We obtained OCTA images by using RTVue XR Avanti OCT with AngioVue®. The images of OCTA with scan size of 8×8 mm were obtained with and without EFI, and then they were compared. Results OCTA with EFI technique was performed successfully in all eyes. The nonperfusion area was well defined in superficial capillary plexus layer. The images with EFI were able to capture the larger area of the fundus by an average of 188.5% than those without EFI. The posterior pole inside the vascular arcade was well covered with this technique. The area of the fundus imaged by OCTA with EFI technique was even larger than that of fluorescein angiography using Heidelberg Retina Angiograph 2, which captured a 30° field. Conclusion Our results suggested that OCTA with EFI technique is very useful to evaluate the retinal ischemia in retinal vein occlusion. PMID:27471374

  1. Unraveling the nature of electric field- and stress- induced structural transformations in soft PZT by a new powder poling technique.

    PubMed

    Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev

    2015-02-25

    A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization. PMID:25629264

  2. Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects

    PubMed Central

    Shin, Yoonseok

    2015-01-01

    Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT) is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN) model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project. PMID:26339227

  3. Wastewater quality monitoring system using sensor fusion and machine learning techniques.

    PubMed

    Qin, Xusong; Gao, Furong; Chen, Guohua

    2012-03-15

    A multi-sensor water quality monitoring system incorporating an UV/Vis spectrometer and a turbidimeter was used to monitor the Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) and Oil & Grease (O&G) concentrations of the effluents from the Chinese restaurant on campus and an electrocoagulation-electroflotation (EC-EF) pilot plant. In order to handle the noise and information unbalance in the fused UV/Vis spectra and turbidity measurements during the calibration model building, an improved boosting method, Boosting-Iterative Predictor Weighting-Partial Least Squares (Boosting-IPW-PLS), was developed in the present study. The Boosting-IPW-PLS method incorporates IPW into boosting scheme to suppress the quality-irrelevant variables by assigning small weights, and builds up the models for the wastewater quality predictions based on the weighted variables. The monitoring system was tested in the field with satisfactory results, underlying the potential of this technique for the online monitoring of water quality. PMID:22200261

  4. GRAIL gravity field recovery using the short-arc integral equation technique: development of the latest Graz lunar gravity field model (GrazLGM)

    NASA Astrophysics Data System (ADS)

    Krauss, S.; Klinger, B.; Baur, O.; Mayr-Guerr, T.

    2015-10-01

    We present an updated version of the lunar gravity field model GrazLGM300a,b [1,2] based on intersatellite Ka-band ranging (KBR) observations collected by the GRAIL mission. We propose to exploit the ranging measurements by an integral equation approach using short orbital arcs [4].Compared to the predecessor model we increase the spectral resolution to degree and order 450 and refined the parameterization. Validation shows that the applied technique is well suited to recover the lunar gravity field.

  5. Development of a Rapid Soil Water Content Detection Technique Using Active Infrared Thermal Methods for In-Field Applications

    PubMed Central

    Antonucci, Francesca; Pallottino, Federico; Costa, Corrado; Rimatori, Valentina; Giorgi, Stefano; Papetti, Patrizia; Menesatti, Paolo

    2011-01-01

    The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s). To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory–based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%). The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information on soil

  6. Development of a rapid soil water content detection technique using active infrared thermal methods for in-field applications.

    PubMed

    Antonucci, Francesca; Pallottino, Federico; Costa, Corrado; Rimatori, Valentina; Giorgi, Stefano; Papetti, Patrizia; Menesatti, Paolo

    2011-01-01

    The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s). To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory-based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%). The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information on soil heterogeneity

  7. Cost-sensitive AdaBoost algorithm for ordinal regression based on extreme learning machine.

    PubMed

    Riccardi, Annalisa; Fernández-Navarro, Francisco; Carloni, Sante

    2014-10-01

    In this paper, the well known stagewise additive modeling using a multiclass exponential (SAMME) boosting algorithm is extended to address problems where there exists a natural order in the targets using a cost-sensitive approach. The proposed ensemble model uses an extreme learning machine (ELM) model as a base classifier (with the Gaussian kernel and the additional regularization parameter). The closed form of the derived weighted least squares problem is provided, and it is employed to estimate analytically the parameters connecting the hidden layer to the output layer at each iteration of the boosting algorithm. Compared to the state-of-the-art boosting algorithms, in particular those using ELM as base classifier, the suggested technique does not require the generation of a new training dataset at each iteration. The adoption of the weighted least squares formulation of the problem has been presented as an unbiased and alternative approach to the already existing ELM boosting techniques. Moreover, the addition of a cost model for weighting the patterns, according to the order of the targets, enables the classifier to tackle ordinal regression problems further. The proposed method has been validated by an experimental study by comparing it with already existing ensemble methods and ELM techniques for ordinal regression, showing competitive results. PMID:25222730

  8. Shell boosts recovery at Kernridge

    SciTech Connect

    Moore, S.

    1984-01-01

    Since acquiring the Kernridge property in December 1979, Shell Oil Co. has drilled more than 1,800 wells and steadily increased production from 42,000 to 89,000 b/d of oil. Currently, the Kernridge Production Division of Shell California Production Inc. (SCPI), a newly formed subsidiary of Shell Oil Co., is operator for the property. The property covers approximately 35,000 mostly contiguous net acres, with production concentrated mainly on about 5,500 net acres. SCPI's four major fields in the area are the North and South Belridge, Lost Hills, and Antelope Hills. Most of the production comes from the North and South Belridge fields, which were previously held by the Belridge Oil Co. Productive horizons in the fields are the Tulare, Diatomite, Brown Shale, Antelope Shale, 64 Zone, and Agua sand. The Tulare and Diatomite are the two major reservoirs SCPI is developing. The Tulare, encountered between 400 and 1,300 ft, is made up of fine- to coarse-grained, unconsolidated sands with interbedded shales and silt stones and contains 13 /sup 0/ API oil. Using steam drive as the main recovery method, SCPI estimates an ultimate recovery from the Tulare formation of about 60% of the original 1 billion barrels in place. The Diatomite horizon, found between 800 and 3,500 ft and containing light, 28 /sup 0/ API oil, has high porosity (more than 60%), low permeability (less than 1 md), and natural fractures. Because of the Diatomite's low permeability, fracture stimulation is being used to increase well productivity. SCPI anticipates that approximately 5% of the almost 2 billion barrels of oil originally in place will be recovered by primary production.

  9. Geometric and Dosimetric Approach to Determine Probability of Late Cardiac Mortality in Left Tangential Breast Irradiation: Comparison Between Wedged Beams and Field-in-Field Technique

    SciTech Connect

    Pili, Giorgio; Grimaldi, Luca; Fidanza, Christian; Florio, Elena T.; Petruzzelli, Maria F.; D'Errico, Maria P.; De Tommaso, Cristina; Tramacere, Francesco; Musaio, Francesca; Castagna, Roberta; Francavilla, Maria C.; Gianicolo, Emilio A.L.; Portaluri, Maurizio

    2011-11-01

    Purpose: To evaluate the probability of late cardiac mortality resulting from left breast irradiation planned with tangential fields and to compare this probability between the wedged beam and field-in-field (FIF) techniques and to investigate whether some geometric/dosimetric indicators can be determined to estimate the cardiac mortality probability before treatment begins. Methods and Materials: For 30 patients, differential dose-volume histograms were calculated for the wedged beam and FIF plans, and the corresponding cardiac mortality probabilities were determined using the relative seriality model. As a comparative index of the dose distribution uniformity, the planning target volume (PTV) percentages involved in 97-103% of prescribed dose were determined for the two techniques. Three geometric parameters were measured for each patient: the maximal length, indicates how much the heart contours were displaced toward the PTV, the angle subtended at the center of the computed tomography slice by the PTV contour, and the thorax width/thickness ratio. Results: Evaluating the differential dose-volume histograms showed that the gain in uniformity between the two techniques was about 1.5. With the FIF technique, the mean dose sparing for the heart, the left anterior descending coronary artery, and the lung was 15% (2.5 Gy vs. 2.2 Gy), 21% (11.3 Gy vs. 9.0 Gy), and 42% (8.0 Gy vs. 4.6 Gy) respectively, compared with the wedged beam technique. Also, the cardiac mortality probability decreased by 40% (from 0.9% to 0.5%). Three geometric parameters, the maximal length, angle subtended at the center of the computed tomography slice by the PTV contour, and thorax width/thickness ratio, were the determining factors (p = .06 for FIF, and p = .10 for wedged beam) for evaluating the cardiac mortality probability. Conclusion: The FIF technique seemed to yield a lower cardiac mortality probability than the conventional wedged beam technique. However, although our study

  10. Obtaining oblique technique source-to-skin distances for irregular field (Clarkson) calculations: The Mayo Off-axis Distance Indicator

    SciTech Connect

    Lajoie, W.N. )

    1988-09-01

    Significant dose inhomogeneities may exist between the supraclavicular fossa (SCF) and the internal mammary chain (IMC) regions in the irregular L-shaped (hockey stick) field associated with breast cancer treatments. This dose inhomogeneity exists, in part, because of a positive air gap in the SCF and a negative air gap in the IMC locations. Independent of treatment technique, (i.e., whether anterior-posterior (AP) or oblique fields are used), accurate source-to-skin distance (SSD) values for the SCF, IMC, and axilla are necessary when doing an irregular field (Clarkson) dose calculation. However, when an oblique technique is used to treat the hockey stick field, obtaining non-central-axis SSDs is not as straightforward as when an AP technique is employed. The Mayo Off-axis Distance Indicator was constructed to slide into the blocking tray slot of the simulator or treatment machine. This mechanical measuring device provides quick and accurate SSD measurements for non-central-axis points under either AP or, more importantly, oblique treatment conditions.

  11. Magnetizing technique for permanent magnets by intense static fields generated by HTS bulk magnets: Numerical Analysis

    NASA Astrophysics Data System (ADS)

    N. Kawasaki; Oka, T.; Fukui, S.; Ogawa, J.; Sato, T.; Terasawa, T.; Itoh, Y.

    A demagnetized Nd-Fe-B permanent magnet was scanned in the strong magnetic field space just above the magnetic pole containing a HTS bulk magnet which generates the magnetic field 3.4 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. The finite element method was carried out for the static field magnetization of a permanent magnet using a HTS bulk magnet. Previously, our research group experimentally demonstrated the possibility of full magnetization of rare earth permanent magnets with high-performance magnetic properties with use of the static field of HTS bulk magnets. In the present study, however, we succeeded for the first time in visualizing the behavior of the magnetizing field of the bulk magnet during the magnetization process and the shape of the magnetic field inside the body being magnetized. By applying this kind of numerical analysis to the magnetization for planned motor rotors which incorporate rare-earth permanent magnets, we hope to study the fully magnetized regions for the new magnetizing method using bulk magnets and to give motor designing a high degree of freedom.

  12. Ultrasonic propagation: a technique to reveal field induced structures in magnetic nanofluids.

    PubMed

    Parekh, Kinnari; Patel, Jaykumar; Upadhyay, R V

    2015-07-01

    The paper reports the study of magnetic field induced structures in magnetic nanofluid investigated through ultrasonic wave propagation. Modified Tarapov's theory is used to study variation in velocity anisotropy with magnetic field. The types of field induced structures depend upon the chemical structure of the carrier in which magnetic nanoparticles are dispersed. Our study indicates formation of fractals and chain respectively, in transformer oil and kerosene based fluid. This difference is explained on the basis of particle-particle interaction and particle-medium interaction. PMID:25791205

  13. Binarization With Boosting and Oversampling for Multiclass Classification.

    PubMed

    Sen, Ayon; Islam, Md Monirul; Murase, Kazuyuki; Yao, Xin

    2016-05-01

    Using a set of binary classifiers to solve multiclass classification problems has been a popular approach over the years. The decision boundaries learnt by binary classifiers (also called base classifiers) are much simpler than those learnt by multiclass classifiers. This paper proposes a new classification framework, termed binarization with boosting and oversampling (BBO), for efficiently solving multiclass classification problems. The new framework is devised based on the one-versus-all (OVA) binarization technique. Unlike most previous work, BBO employs boosting for solving the hard-to-learn instances and oversampling for handling the class-imbalance problem arising due to OVA binarization. These two features make BBO different from other existing works. Our new framework has been tested extensively on several multiclass supervised and semi-supervised classification problems using five different base classifiers, including neural networks, C4.5, k -nearest neighbor, repeated incremental pruning to produce error reduction, support vector machine, random forest, and learning with local and global consistency. Experimental results show that BBO can exhibit better performance compared to its counterparts on supervised and semi-supervised classification problems. PMID:25955858

  14. A Jiles-Atherton and fixed-point combined technique for time periodic magnetic field problems with hysteresis

    SciTech Connect

    Chiampi, M.; Repetto, M.; Chiarabaglio, D.

    1995-11-01

    The hysteresis phenomenon can significantly affect the behavior of magnetic cores in electrical machines and devices. This paper presents a finite element solution of periodic steady state magnetic field problems in soft materials with scalar hysteresis. The Jiles-Atherton model is employed for the generation of symmetric B-H loops and it is coupled with the Fixed Point Technique for handling magnetic nonlinearities. The proposed procedure is applied to a hysteretic model problem whose analytical solution is available. The results show that the Fixed Point Technique can efficiently deal with non-single valued material characteristics under periodic operating conditions.

  15. A comparison of TPS and different measurement techniques in small-field electron beams.

    PubMed

    Donmez Kesen, Nazmiye; Cakir, Aydin; Okutan, Murat; Bilge, Hatice

    2015-01-01

    In recent years, small-field electron beams have been used for the treatment of superficial lesions, which requires small circular fields. However, when using very small electron fields, some significant dosimetric problems may occur. In this study, dose distributions and outputs of circular fields with dimensions of 5cm and smaller, for nominal energies of 6, 9, and 15MeV from the Siemens ONCOR Linac, were measured and compared with data from a treatment planning system using the pencil-beam algorithm in electron beam calculations. All dose distribution measurements were performed using the Gafchromic EBT film; these measurements were compared with data that were obtained from the Computerized Medical Systems (CMS) XiO treatment planning system (TPS), using the gamma-index method in the PTW VeriSoft software program. Output measurements were performed using the Gafchromic EBT film, an Advanced Markus ion chamber, and thermoluminescent dosimetry (TLD). Although the pencil-beam algorithm is used to model electron beams in many clinics, there is no substantial amount of detailed information in the literature about its use. As the field size decreased, the point of maximum dose moved closer to the surface. Output factors were consistent; differences from the values obtained from the TPS were, at maximum, 42% for 6 and 15MeV and 32% for 9MeV. When the dose distributions from the TPS were compared with the measurements from the Gafchromic EBT films, it was observed that the results were consistent for 2-cm diameter and larger fields, but the outputs for fields of 1-cm diameter and smaller were not consistent. In CMS XiO TPS, calculated using the pencil-beam algorithm, the dose distributions of electron treatment fields that were created with circular cutout of a 1-cm diameter were not appropriate for patient treatment and the pencil-beam algorithm is not convenient for monitor unit (MU) calculations in electron dosimetry. PMID:25219322

  16. Expert knowledge techniques applied to the analysis of electric field mill data

    NASA Technical Reports Server (NTRS)

    Nicholson, James R.; Mulvehill, Alice M.

    1990-01-01

    NASA operates a network of ground-based electric field mills at Kennedy Space Center (KSC) to identify clouds which might be an electrical hazard to space vehicle prior to and during launch or to the various ground operations performed at the center. Artificial intelligence has been used to develop an expert system for analyzing electric field mill data. The application of the system to expert system to small thunderstorms at KSC is shown.

  17. A comparison of TPS and different measurement techniques in small-field electron beams

    SciTech Connect

    Donmez Kesen, Nazmiye Cakir, Aydin; Okutan, Murat; Bilge, Hatice

    2015-04-01

    In recent years, small-field electron beams have been used for the treatment of superficial lesions, which requires small circular fields. However, when using very small electron fields, some significant dosimetric problems may occur. In this study, dose distributions and outputs of circular fields with dimensions of 5 cm and smaller, for nominal energies of 6, 9, and 15 MeV from the Siemens ONCOR Linac, were measured and compared with data from a treatment planning system using the pencil-beam algorithm in electron beam calculations. All dose distribution measurements were performed using the Gafchromic EBT film; these measurements were compared with data that were obtained from the Computerized Medical Systems (CMS) XiO treatment planning system (TPS), using the gamma-index method in the PTW VeriSoft software program. Output measurements were performed using the Gafchromic EBT film, an Advanced Markus ion chamber, and thermoluminescent dosimetry (TLD). Although the pencil-beam algorithm is used to model electron beams in many clinics, there is no substantial amount of detailed information in the literature about its use. As the field size decreased, the point of maximum dose moved closer to the surface. Output factors were consistent; differences from the values obtained from the TPS were, at maximum, 42% for 6 and 15 MeV and 32% for 9 MeV. When the dose distributions from the TPS were compared with the measurements from the Gafchromic EBT films, it was observed that the results were consistent for 2-cm diameter and larger fields, but the outputs for fields of 1-cm diameter and smaller were not consistent. In CMS XiO TPS, calculated using the pencil-beam algorithm, the dose distributions of electron treatment fields that were created with circular cutout of a 1-cm diameter were not appropriate for patient treatment and the pencil-beam algorithm is not convenient for monitor unit (MU) calculations in electron dosimetry.

  18. Non-linear force-free field modeling: model techniques, boundary conditions, hares, and hounds

    NASA Astrophysics Data System (ADS)

    Schrijver, C. J.; De Rosa, M. L.; Metcalf, T.

    2005-05-01

    Understanding the conditions under which solar magnetic fields can destabilize to erupt in flares and coronal mass ejections requires a quantitative understanding of the coronal magnetic field and of the currents that it carries. The increased availability of vector magnetograms, together with EUV and X-ray coronal images, should provide adequate constraints to model the coronal field, and thus to visualize its 3D geometry and to measure the available free energy and helicity. Non-linear force-free fields (NLFFF) are likely a useful model to use when extrapolating the solar surface field upward into the coronal volume. It may even be possible to use the observed trajectories of coronal loops, evident in EUV images of the corona, as a further constraint. We present initial results of a team effort to understand the intricacies of NLFFF modeling: we discuss and evaluate comparisons of NLFFF models computed with different models and applications of boundary conditions, and look ahead to full coronal field modeling for the upcoming Solar-B and SDO missions.

  19. Field Emission studies of Silicon nanowires grown by Vapor-Liquid-Solid (VLS) technique

    NASA Astrophysics Data System (ADS)

    Kulkarni, Niraj; Bae, Joonho; Stanley, Scott; Coffee, Shawn; Ekerdt, John; Yao, Zhen; Shih, Chih-Kang

    2004-03-01

    Semiconductor nanowires among other 1-D nanostructures are potential candidates for field emission applications by virtue of their small tip radii and large aspect ratios. In this regard field emission properties of silicon nanowires are investigated. Silicon as a material has processing advantages over others because it has been well researched over the past decades. Silicon nanowires are grown by hot wire chemical vapor deposition (CVD) of disilane at approximately 600 C. The growth takes place via vapor-liquid-solid (VLS) mechanism with a thin film (20 nm) of gold acting as a catalyst. VLS growth enables large area coverage and also offers scalability. Field emission studies of these samples will be reported. Preliminary studies indicate a threshold field of 10-15 V/μ m. As a consequence of VLS growth, the catalyst (gold) resides at the tip of the nanowire and can be etched away by aqua regia. The effect of gold removal on the field emission characteristics will be reported. Silicon also offers an additional degree of freedom in terms of doping to engineer the position of the Fermi level. The effect of doping on the field emission characteristics will also be reported.

  20. Multimodal wide-field two-photon excitation imaging: characterization of the technique for in vivo applications.

    PubMed

    Hwang, Jae Youn; Wachsmann-Hogiu, Sebastian; Ramanujan, V Krishnan; Nowatzyk, Andreas G; Koronyo, Yosef; Medina-Kauwe, Lali K; Gross, Zeev; Gray, Harry B; Farkas, Daniel L

    2011-01-01

    We report fast, non-scanning, wide-field two-photon fluorescence excitation with spectral and lifetime detection for in vivo biomedical applications. We determined the optical characteristics of the technique, developed a Gaussian flat-field correction method to reduce artifacts resulting from non-uniform excitation such that contrast is enhanced, and showed that it can be used for ex vivo and in vivo cellular-level imaging. Two applications were demonstrated: (i) ex vivo measurements of beta-amyloid plaques in retinas of transgenic mice, and (ii) in vivo imaging of sulfonated gallium(III) corroles injected into tumors. We demonstrate that wide-field two photon fluorescence excitation with flat-field correction provides more penetration depth as well as better contrast and axial resolution than the corresponding one-photon wide field excitation for the same dye. Importantly, when this technique is used together with spectral and fluorescence lifetime detection modules, it offers improved discrimination between fluorescence from molecules of interest and autofluorescence, with higher sensitivity and specificity for in vivo applications. PMID:21339880

  1. Micro gel column technique is fit for detecting mixed fields post ABO incompatible hematopoietic stem cell transplantation.

    PubMed

    Li, Min-Fang; Liu, Feng; Zhang, Min

    2015-04-01

    How to choose suitable serologic method for assessment of the actual stages of ABO chimera is more important to establish transfusion strategy for patients post-ABO incompatible hematopoietic stem cell transplantation. We reported ABO phenotypes of a patient post-ABO minor incompatible hematopoietic stem cell transplantation from 1+ weak agglutination by tube method was obviously reaffirmed to mixed fields with 4+ positive reaction by micro gel column card. Hence, blood bank technologists must continually work together with hematologist to establish appropriate transfusion strategy, and micro gel column technique can be more appropriate for detecting mixed fields during the whole period of transplantation. PMID:25578650

  2. DIRBoost-an algorithm for boosting deformable image registration: application to lung CT intra-subject registration.

    PubMed

    Muenzing, Sascha E A; van Ginneken, Bram; Viergever, Max A; Pluim, Josien P W

    2014-04-01

    We introduce a boosting algorithm to improve on existing methods for deformable image registration (DIR). The proposed DIRBoost algorithm is inspired by the theory on hypothesis boosting, well known in the field of machine learning. DIRBoost utilizes a method for automatic registration error detection to obtain estimates of local registration quality. All areas detected as erroneously registered are subjected to boosting, i.e. undergo iterative registrations by employing boosting masks on both the fixed and moving image. We validated the DIRBoost algorithm on three different DIR methods (ANTS gSyn, NiftyReg, and DROP) on three independent reference datasets of pulmonary image scan pairs. DIRBoost reduced registration errors significantly and consistently on all reference datasets for each DIR algorithm, yielding an improvement of the registration accuracy by 5-34% depending on the dataset and the registration algorithm employed. PMID:24556079

  3. Electric field modulation technique for high-voltage AlGaN/GaN Schottky barrier diodes

    NASA Astrophysics Data System (ADS)

    Tang, Cen; Xie, Gang; Zhang, Li; Guo, Qing; Wang, Tao; Sheng, Kuang

    2013-10-01

    A novel structure of AlGaN/GaN Schottky barrier diode (SBD) featuring electric field optimization techniques of anode-connected-field-plate (AFP) and magnesium-doped p-type buried layer under the two-dimensional electron gas (2DEG) channel is proposed. In comparison with conventional AlGaN/GaN SBDs, the magnesium-doped p-type buried layer in the proposed structure can provide holes that can help to deplete the surface 2DEG. As a result, surface field strength around the electrode edges is significantly suppressed and the electric field along the channel is distributed more evenly. Through 2D numerical analysis, the AFP parameters (field plate length, LAFP, and field plate height, TAFP) and p-type buried layer parameters (p-type layer concentration, NP, and p-type layer thickness, TP) are optimized to achieve a three-equal-peak surface channel field distribution under exact charge balance conditions. A novel structure with a total drift region length of 10.5 μm and a magnesium-doped p-type concentration of 1 × 1017 cm-3 achieves a high breakdown voltage (VB) of 1.8 kV, showing 5 times improvement compared with the conventional SBD with the same device dimension.

  4. Role of Brachytherapy in the Boost Management of Anal Carcinoma With Node Involvement (CORS-03 Study)

    SciTech Connect

    Moureau-Zabotto, Laurence; Ortholan, Cecile; Hannoun-Levi, Jean-Michel; Teissier, Eric; Cowen, Didier; Salem, Nagi; Lemanski, Claire; Ellis, Steve; Resbeut, Michel

    2013-03-01

    Purpose: To assess retrospectively the clinical outcome in anal cancer patients, with lymph node involvement, treated with split-course radiation therapy and receiving a boost through external beam radiation therapy (EBRT) or brachytherapy (BCT). Methods and Materials: From 2000 to 2005, among 229 patients with invasive nonmetastatic anal squamous cell carcinoma, a selected group of 99 patients, with lymph node involvement, was studied. Tumor staging reported was T1 in 4 patients, T2 in 16 patients, T3 in 49 patients, T4 in 16 patients, and T unknown in 14 patients and as N1 in 67 patients and N2/N3 in 32 patients. Patients underwent a first course of EBRT (mean dose, 45.1 Gy) followed by a boost (mean dose, 18 Gy) using EBRT (50 patients) or BCT (49 patients). All characteristics of patients and tumors were well balanced between the BCT and EBRT groups. Prognostic factors of cumulative rate of local recurrence (CRLR), cumulative rate of distant (including nodal) recurrence (CRDR), colostomy-free survival (CFS) rate, and overall survival (OS) rate were analyzed for the overall population and according to the nodal status classification. Results: The median follow-up was 71.5 months. The 5-year CRLR, CRDR, CFS rate, and OS rate were 21%, 19%, 63%, and 74.4%, respectively. In the overall population, the type of node involvement (N1 vs N2/N3) was the unique independent prognostic factor for CRLR. In N1 patients, by use of multivariate analysis, BCT boost was the unique prognostic factor for CRLR (4% for BCT vs 31% for EBRT; hazard ratio, 0.08; P=.042). No studied factors were significantly associated with CRDR, CFS, and OS. No difference with regard to boost technique and any other factor studied was observed in N2/N3 patients for any kind of recurrence. Conclusion: In anal cancer, even in the case of initial perirectal node invasion, BCT boost is superior to EBRT boost for CRLR, without an influence on OS, suggesting that N1 status should not be a contraindication to

  5. Commissioning a small-field biological irradiator using point, 2D, and 3D dosimetry techniques

    PubMed Central

    Newton, Joseph; Oldham, Mark; Thomas, Andrew; Li, Yifan; Adamovics, John; Kirsch, David G.; Das, Shiva

    2011-01-01

    Purpose: To commission a small-field biological irradiator, the XRad225Cx from Precision x-Ray, Inc., for research use. The system produces a 225 kVp x-ray beam and is equipped with collimating cones that produce both square and circular radiation fields ranging in size from 1 to 40 mm. This work incorporates point, 2D, and 3D measurements to determine output factors (OF), percent-depth-dose (PDD) and dose profiles at multiple depths. Methods: Three independent dosimetry systems were used: ion-chambers (a farmer chamber and a micro-ionisation chamber), 2D EBT2 radiochromic film, and a novel 3D dosimetry system (DLOS/PRESAGE®). Reference point dose rates and output factors were determined from in-air ionization chamber measurements for fields down to ∼13 mm using the formalism of TG61. PDD, profiles, and output factors at three separate depths (0, 0.5, and 2 cm), were determined for all field sizes from EBT2 film measurements in solid water. Several film PDD curves required a scaling correction, reflecting the challenge of accurate film alignment in very small fields. PDDs, profiles, and output factors were also determined with the 3D DLOS/PRESAGE® system which generated isotropic 0.2 mm data, in scan times of 20 min. Results: Surface output factors determined by ion-chamber were observed to gradually drop by ∼9% when the field size was reduced from 40 to 13 mm. More dramatic drops were observed for the smallest fields as determined by EBT∼18% and ∼42% for the 2.5 mm and 1 mm fields, respectively. PRESAGE® and film output factors agreed well for fields <20 mm (where 3D data were available) with mean deviation of 2.2% (range 1%–4%). PDD values at 2 cm depth varied from ∼72% for the 40 mm field, down to ∼55% for the 1 mm field. EBT and PRESAGE® PDDs agreed within ∼3% in the typical therapy region (1–4 cm). At deeper depths the EBT curves were slightly steeper (2.5% at 5 cm). These results indicate good overall consistency between ion-chamber, EBT

  6. Commissioning a small-field biological irradiator using point, 2D, and 3D dosimetry techniques

    SciTech Connect

    Newton, Joseph; Oldham, Mark; Thomas, Andrew; Li Yifan; Adamovics, John; Kirsch, David G.; Das, Shiva

    2011-12-15

    Purpose: To commission a small-field biological irradiator, the XRad225Cx from Precision x-Ray, Inc., for research use. The system produces a 225 kVp x-ray beam and is equipped with collimating cones that produce both square and circular radiation fields ranging in size from 1 to 40 mm. This work incorporates point, 2D, and 3D measurements to determine output factors (OF), percent-depth-dose (PDD) and dose profiles at multiple depths. Methods: Three independent dosimetry systems were used: ion-chambers (a farmer chamber and a micro-ionisation chamber), 2D EBT2 radiochromic film, and a novel 3D dosimetry system (DLOS/PRESAGE registered ). Reference point dose rates and output factors were determined from in-air ionization chamber measurements for fields down to {approx}13 mm using the formalism of TG61. PDD, profiles, and output factors at three separate depths (0, 0.5, and 2 cm), were determined for all field sizes from EBT2 film measurements in solid water. Several film PDD curves required a scaling correction, reflecting the challenge of accurate film alignment in very small fields. PDDs, profiles, and output factors were also determined with the 3D DLOS/PRESAGE registered system which generated isotropic 0.2 mm data, in scan times of 20 min. Results: Surface output factors determined by ion-chamber were observed to gradually drop by {approx}9% when the field size was reduced from 40 to 13 mm. More dramatic drops were observed for the smallest fields as determined by EBT{approx}18% and {approx}42% for the 2.5 mm and 1 mm fields, respectively. PRESAGE registered and film output factors agreed well for fields <20 mm (where 3D data were available) with mean deviation of 2.2% (range 1%-4%). PDD values at 2 cm depth varied from {approx}72% for the 40 mm field, down to {approx}55% for the 1 mm field. EBT and PRESAGE registered PDDs agreed within {approx}3% in the typical therapy region (1-4 cm). At deeper depths the EBT curves were slightly steeper (2.5% at 5 cm

  7. ADAPTING WOODY SPECIES AND PLANTING TECHNIQUES TO LANDFILL CONDITIONS, FIELD AND LABORATORY INVESTIGATIONS

    EPA Science Inventory

    A study was undertaken to determine which tree species can best maintain themselves in a landfill environment; to investigate the feasibility of preventing landfill gas from penetrating the root zone of selected species by using gas-barrier techniques; and to identify the (those)...

  8. Bioactive Molecule Prediction Using Extreme Gradient Boosting.

    PubMed

    Babajide Mustapha, Ismail; Saeed, Faisal

    2016-01-01

    Following the explosive growth in chemical and biological data, the shift from traditional methods of drug discovery to computer-aided means has made data mining and machine learning methods integral parts of today's drug discovery process. In this paper, extreme gradient boosting (Xgboost), which is an ensemble of Classification and Regression Tree (CART) and a variant of the Gradient Boosting Machine, was investigated for the prediction of biological activity based on quantitative description of the compound's molecular structure. Seven datasets, well known in the literature were used in this paper and experimental results show that Xgboost can outperform machine learning algorithms like Random Forest (RF), Support Vector Machines (LSVM), Radial Basis Function Neural Network (RBFN) and Naïve Bayes (NB) for the prediction of biological activities. In addition to its ability to detect minority activity classes in highly imbalanced datasets, it showed remarkable performance on both high and low diversity datasets. PMID:27483216

  9. Study of two-dimensional transient cavity fields using the finite-difference time-domain technique

    SciTech Connect

    Crisp, J.L.

    1988-06-01

    This work is intended to be a study into the application of the finite-difference time-domain, or FD-TD technique, to some of the problems faced by designers of equipment used in modern accelerators. In particular it discusses using the FD-TD algorithm to study the field distribution of a simple two-dimensional cavity in both space and time. 18 refs.

  10. The Development of a Full Field Three-Dimensional Microscale Flow Measurement Technique for Application to Near Contact Line Flows

    NASA Technical Reports Server (NTRS)

    He, Qun; Hallinan, Kevin

    1996-01-01

    The goal of this paper is to present details of the development of a new three-dimensional velocity field measurement technique which can be used to provide more insight into the dynamics of thin evaporating liquid films (not limited to just low heat inputs for the heat transfer) and which also could prove useful for the study of spreading and wetting phenomena and other microscale flows.

  11. Enhanced carbonate reservoir model for an old reservoir utilizing new techniques: The Schaben Field (Mississippian), Ness County, Kansas

    SciTech Connect

    Carr, T.P.; Guy, W.J.; Franseen, E.K.; Bhattacharya, S. )

    1996-01-01

    The Pennsylvanian-Mississippian unconformity is a major stratigraphic event in Kansas that truncates rocks ranging from Precambrian to Mississippian. Many of the 6,000 fields in Kansas are located immediately beneath this unconformity. One example, Schaben Field located in Ness County, Kansas, has produced approximately 9 million barrels since it was discovered in 1963. Production is from the Mississippian (Osagian) cherty dolomites beneath the inconformity. The field was initially developed on a regular forty-acre spacing, but recent drilling has demonstrated the potential for additional targeted infill drilling. To develop an enhanced reservoir model for the Schabin field modern core, log, and well data were integrated with the existing data. New techniques such as [open quotes]Pseudoseismic[close quotes] and the [open quotes]Super[close quotes] Pickett plot were used to leverage the existing data and provide tools for analysis and 3D visualization. The pseudoseismic approach uses well-logs within a standard 3D seismic visualization system to provide a detailed macroscale view of karst patterns. The petrophysical analyses using the [open quotes]Super[close quotes] Pickett plot were used to recognize subtle trends and patterns for each of multiple reservoir intervals. Visual and petrographic examination of core from the field confirms karst development and indicates multiple stages of fracturing, brecciation, and dissolution features that were important in controlling and modifying development of reservoirs. The understanding of the reservoir heterogeneities resulting from the paleokarst model at Schaben field emphasizes the importance of integrating available data with new techniques to provide a predictive tool for discovery of additional pay within existing subunconformity fields in Kansas.

  12. Enhanced carbonate reservoir model for an old reservoir utilizing new techniques: The Schaben Field (Mississippian), Ness County, Kansas

    SciTech Connect

    Carr, T.P.; Guy, W.J.; Franseen, E.K.; Bhattacharya, S.

    1996-12-31

    The Pennsylvanian-Mississippian unconformity is a major stratigraphic event in Kansas that truncates rocks ranging from Precambrian to Mississippian. Many of the 6,000 fields in Kansas are located immediately beneath this unconformity. One example, Schaben Field located in Ness County, Kansas, has produced approximately 9 million barrels since it was discovered in 1963. Production is from the Mississippian (Osagian) cherty dolomites beneath the inconformity. The field was initially developed on a regular forty-acre spacing, but recent drilling has demonstrated the potential for additional targeted infill drilling. To develop an enhanced reservoir model for the Schabin field modern core, log, and well data were integrated with the existing data. New techniques such as {open_quotes}Pseudoseismic{close_quotes} and the {open_quotes}Super{close_quotes} Pickett plot were used to leverage the existing data and provide tools for analysis and 3D visualization. The pseudoseismic approach uses well-logs within a standard 3D seismic visualization system to provide a detailed macroscale view of karst patterns. The petrophysical analyses using the {open_quotes}Super{close_quotes} Pickett plot were used to recognize subtle trends and patterns for each of multiple reservoir intervals. Visual and petrographic examination of core from the field confirms karst development and indicates multiple stages of fracturing, brecciation, and dissolution features that were important in controlling and modifying development of reservoirs. The understanding of the reservoir heterogeneities resulting from the paleokarst model at Schaben field emphasizes the importance of integrating available data with new techniques to provide a predictive tool for discovery of additional pay within existing subunconformity fields in Kansas.

  13. Background field removal technique using regularization enabled sophisticated harmonic artifact reduction for phase data with varying kernel sizes.

    PubMed

    Kan, Hirohito; Kasai, Harumasa; Arai, Nobuyuki; Kunitomo, Hiroshi; Hirose, Yasujiro; Shibamoto, Yuta

    2016-09-01

    An effective background field removal technique is desired for more accurate quantitative susceptibility mapping (QSM) prior to dipole inversion. The aim of this study was to evaluate the accuracy of regularization enabled sophisticated harmonic artifact reduction for phase data with varying spherical kernel sizes (REV-SHARP) method using a three-dimensional head phantom and human brain data. The proposed REV-SHARP method used the spherical mean value operation and Tikhonov regularization in the deconvolution process, with varying 2-14mm kernel sizes. The kernel sizes were gradually reduced, similar to the SHARP with varying spherical kernel (VSHARP) method. We determined the relative errors and relationships between the true local field and estimated local field in REV-SHARP, VSHARP, projection onto dipole fields (PDF), and regularization enabled SHARP (RESHARP). Human experiment was also conducted using REV-SHARP, VSHARP, PDF, and RESHARP. The relative errors in the numerical phantom study were 0.386, 0.448, 0.838, and 0.452 for REV-SHARP, VSHARP, PDF, and RESHARP. REV-SHARP result exhibited the highest correlation between the true local field and estimated local field. The linear regression slopes were 1.005, 1.124, 0.988, and 0.536 for REV-SHARP, VSHARP, PDF, and RESHARP in regions of interest on the three-dimensional head phantom. In human experiments, no obvious errors due to artifacts were present in REV-SHARP. The proposed REV-SHARP is a new method combined with variable spherical kernel size and Tikhonov regularization. This technique might make it possible to be more accurate backgroud field removal and help to achive better accuracy of QSM. PMID:27114339

  14. Experimental characterization of rupture in human aortic aneurysms using a full-field measurement technique.

    PubMed

    Kim, Jin-Hwan; Avril, Stéphane; Duprey, Ambroise; Favre, Jean-Pierre

    2012-07-01

    The present study aims at investigating biomechanical failure behaviour of human aneurismal aortic tissues so as to diagnose the rupture risk of aneurysms more accurately. An inflation test is performed on aneurismal aortic tissues up to failure and full-field measurements are achieved using stereo digital image correlation. Then, an appropriate constitutive model derived from histological structure of arteries is adopted to retrieve the Cauchy stress. The virtual fields method is used as an inverse procedure to identify material parameters. Next, the Cauchy stress components are calculated from the identified parameters and the measured Lagrange strain fields. Finally, an important stress parameter which can quantify the strength of aneurismal tissues is derived from the failure stress of aneurismal tissues. PMID:22048330

  15. Synchrotron microimaging technique for measuring the velocity fields of real blood flows

    SciTech Connect

    Lee, Sang-Joon; Kim, Guk Bae

    2005-03-15

    Angiography and Doppler methods used for diagnosing vascular diseases give information on the shape of blood vessels and pointwise blood speed but do not provide detailed information on the flow fields inside the blood vessels. In this study, we developed a method for visualizing blood flow by using coherent synchrotron x rays. This method, which does not require the addition of any contrast agent or tracer particles, visualizes the flow pattern of blood by enhancing the diffraction and interference characteristics of the blood cells. This was achieved by optimizing the sample- (blood) to-detector (charge-coupled device camera) distance and the sample thickness. The proposed method was used to extract quantitative velocity field information from blood flowing inside an opaque microchannel by applying a two-frame particle image velocimetry algorithm to enhanced x-ray images of the blood flow. The measured velocity field data showed a flow structure typical of flow in a macrochannel.

  16. Geological techniques utilized in trap Spring Field discovery, Railroad Valley, Nye County, Nevada

    SciTech Connect

    Dolly, E.D.

    1980-01-01

    The trap at Eagle Springs Field is a combination stratigraphic truncation-subcrop-fault trap. Production occurs from matrix and fracture porosity in reservoirs in the Sheep Pass Formation (Cretaceous and Eocene) and the Garrett Ranch volcanic group (Oligocene). Probably the most unique feature about the field is that the production occurs from the highest position on the lowermost fault block at the basin margin. On the adjacent higher fault blocks the reservoir beds were removed by erosion during the basin and range orogenic event. The position of the truncated edge of the lower Tertiary reservoir units is controlled by the fault pattern at the margin of the valley-basin Graben. Detailed geomorphic studies indicated that this fault pattern may be identified at the surface. Regional geomorphic mapping of fault patterns was conducted to localize areas with possible subcrop truncation patterns similar to Eagle Springs Field. 20 references.

  17. Ultrawide band multifrequency high-field EMR technique: A methodology for increasing spectroscopic information.

    PubMed

    Hassan, A K; Pardi, L A; Krzystek, J; Sienkiewicz, A; Goy, P; Rohrer, M; Brunel, L C

    2000-02-01

    We report methodology that combines an ultrawide band multifrequency microwave system with technology of high magnetic fields for solving challenging problems in electron magnetic resonance (EMR) spectroscopy. This strategy has been made possible due to a novel EMR facility operating in an exceptionally wide range of microwave frequencies of 24 GHz to 3 THz, at magnetic fields up to 17 T, and in the temperature range of 1.6 to 330 K. The basic configuration of the multifrequency system works in a transmission mode and employs oversized cylindrical waveguides for routing the microwave power. A wide-band, low-noise, liquid helium cooled (4.2 K) InSb bolometer is used for signal detection. This approach results in an extremely wide-band performance, thus making it possible to employ a variety of solid-state millimeter and submillimeter microwave sources in combination with a far infrared laser microwave source for performing multifrequency EMR experiments. A complexity of resonant structures and related technical problems such as microphonics at high magnetic fields is virtually eliminated. The system is simple, yet sensitive, and has been revealed to be extremely advantageous while solving such problems as observation of AFMR transitions in spin-ordered systems, g-factor resolution enhancement in complex organic radicals, and resonance signal detection in EMR-silent spin systems having integer spin and large zero field splitting. A technical description of the multifrequency high-field EMR facility is presented and results of its performance tests are given. The potential utility of using the multifrequency high-field methodology in EMR studies is illustrated with selected examples of its recent applications. PMID:10648147

  18. Application of digital interferogram evaluation techniques to the measurement of 3-D flow fields

    NASA Technical Reports Server (NTRS)

    Becker, Friedhelm; Yu, Yung H.

    1987-01-01

    A system for digitally evaluating interferograms, based on an image processing system connected to a host computer, was implemented. The system supports one- and two-dimensional interferogram evaluations. Interferograms are digitized, enhanced, and then segmented. The fringe coordinates are extracted, and the fringes are represented as polygonal data structures. Fringe numbering and fringe interpolation modules are implemented. The system supports editing and interactive features, as well as graphic visualization. An application of the system to the evaluation of double exposure interferograms from the transonic flow field around a helicopter blade and the reconstruction of the three dimensional flow field is given.

  19. Extended-field coverage hyperspectral camera based on a single-pixel technique.

    PubMed

    Jin, Senlin; Hui, Wangwei; Liu, Bo; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2016-06-20

    A spectral single-pixel imaging system facilitates effective image compression, but the imaging region is limited by its single detector. This paper presents a hyperspectral camera that allows extended-field coverage to be collected by one detector. Compressive data of a large field of view is achieved by our highly sensitive detection camera, which can be extended to near-infrared or infrared spectral monitoring. We acquire a hyperspectral datacube of 256×256 spatial pixels and 3 nm spectral resolution at a sampling rate of 25%. Finally, we apply our camera to monitoring fruit freshness nondestructively by differentiating a banana's ripeness over time. PMID:27409103

  20. Techniques for application of faecal DNA methods to field studies of Ursids.

    PubMed

    Wasser, S K; Houston, C S; Koehler, G M; Cadd, G G; Fain, S R

    1997-11-01

    We describe methods for the preservation, extraction and amplification of DNA from faeces that facilitate field applications of faecal DNA technology. Mitochondrial, protein encoding and microsatellite nuclear DNA extracted and amplified from faeces of Malayan sun bears and North American black bears is shown to be identical to that extracted and amplified from the same individual's tissue or blood. A simple drying agent, silica beads, is shown to be a particularly effective preservative, allowing easy and safe transport of samples from the field. Methods are also developed to eliminate the risk of faecal DNA contamination from hair present in faeces. PMID:9394465

  1. Improvements of the gravity field from satellite techniques as proposed to the European Space Agency

    NASA Technical Reports Server (NTRS)

    Reigber, C.

    1978-01-01

    A summary of the European Earth Sciences Space Programme and the requirements for each gravity field mapping resulting from this programme are given. Three satellite experiments for gravity field improvement proposed to the European Space Agency in the last years are shortly characterized. One of these experiments, the low-low-SST-SLALOM experiment, based on laser interferometry for a "two target-one Spacelab telescope" configuration, is discussed in more detail. Reasons for the low-low concept selection are given and some mission aspects and a possible system concept for a compact ranging, acquisition and tracking system are presented.

  2. Development of Techniques for Visualization of Scalar and Vector Fields in the Immersive Environment

    NASA Technical Reports Server (NTRS)

    Bidasaria, Hari B.; Wilson, John W.; Nealy, John E.

    2005-01-01

    Visualization of scalar and vector fields in the immersive environment (CAVE - Cave Automated Virtual Environment) is important for its application to radiation shielding research at NASA Langley Research Center. A complete methodology and the underlying software for this purpose have been developed. The developed software has been put to use for the visualization of the earth s magnetic field, and in particular for the study of the South Atlantic Anomaly. The methodology has also been put to use for the visualization of geomagnetically trapped protons and electrons within Earth's magnetosphere.

  3. Application of Vibration Pattern Imaging to modal analysis; a comparison with full-field and point measurement techniques

    NASA Astrophysics Data System (ADS)

    Bream, R. G.; Gasper, B. C.; Lloyd, Brian E.; Everett, G. M.

    1989-07-01

    The application of structural dynamics principles and procedures to power station plant integrity assessment and condition monitoring encompasses both theoretical and experimental methods. In recent years structural dynamic response measurement has been developed to include non-contacting full-field measurement techniques such as laser holography, Stress Pattern Analysis by measurement of Thermal Emission (SPATE), and more recently Vibration Pattern Imaging (VPI). These full-field techniques have complemented the conventional point measurement methods with a degree of structural dynamic visualisation which was historically felt to be unachievable. This paper presents an assessment of one of the latest techniques, Vibration Pattern Imaging, applied to modal testing utilising a specially designed 'T' section plate as the test specimen. A comparison of the dynamic behaviour of the plate was performed using the following techniques: (i) Vibration Pattern Imaging, (ii) finite element modelling, (iii) frequency response function measurement, (iv) pulsed holography, and (v) Stress Pattern Analysis by measurement of Thermal Emission. In addition, the capability of the VPI to operate as a non-contacting vibration transducer for use in a standard modal analysis is compared with the performance of a conventional piezoelectric accelerometer.

  4. Dosimetric evaluation of simultaneous integrated boost during stereotactic body radiation therapy for pancreatic cancer

    SciTech Connect

    Yang, Wensha; Reznik, Robert; Fraass, Benedick A.; Nissen, Nicholas; Hendifar, Andrew; Wachsman, Ashley; Sandler, Howard; Tuli, Richard

    2015-04-01

    Stereotactic body radiation therapy (SBRT) provides a promising way to treat locally advanced pancreatic cancer and borderline resectable pancreatic cancer. A simultaneous integrated boost (SIB) to the region of vessel abutment or encasement during SBRT has the potential to downstage otherwise likely positive surgical margins. Despite the potential benefit of using SIB-SBRT, the ability to boost is limited by the local geometry of the organs at risk (OARs), such as stomach, duodenum, and bowel (SDB), relative to tumor. In this study, we have retrospectively replanned 20 patients with 25 Gy prescribed to the planning target volume (PTV) and 33~80 Gy to the boost target volume (BTV) using an SIB technique for all patients. The number of plans and patients able to satisfy a set of clinically established constraints is analyzed. The ability to boost vessels (within the gross target volume [GTV]) is shown to correlate with the overlap volume (OLV), defined to be the overlap between the GTV + a 1(OLV1)- or 2(OLV2)-cm margin with the union of SDB. Integral dose, boost dose contrast (BDC), biologically effective BDC, tumor control probability for BTV, and normal tissue complication probabilities are used to analyze the dosimetric results. More than 65% of the cases can deliver a boost to 40 Gy while satisfying all OAR constraints. An OLV2 of 100 cm{sup 3} is identified as the cutoff volume: for cases with OLV2 larger than 100 cm{sup 3}, it is very unlikely the case could achieve 25 Gy to the PTV while successfully meeting all the OAR constraints.

  5. Long-Term Results of Targeted Intraoperative Radiotherapy (Targit) Boost During Breast-Conserving Surgery

    SciTech Connect

    Vaidya, Jayant S.; Baum, Michael; Tobias, Jeffrey S.; Wenz, Frederik; Massarut, Samuele; Keshtgar, Mohammed; Hilaris, Basil; Saunders, Christobel; Williams, Norman R.; Brew-Graves, Chris; Corica, Tammy; Roncadin, Mario; Kraus-Tiefenbacher, Uta; Suetterlin, Marc; Bulsara, Max; Joseph, David

    2011-11-15

    Purpose: We have previously shown that delivering targeted radiotherapy to the tumour bed intraoperatively is feasible and desirable. In this study, we report on the feasibility, safety, and long-term efficacy of TARGeted Intraoperative radioTherapy (Targit), using the Intrabeam system. Methods and Materials: A total of 300 cancers in 299 unselected patients underwent breast-conserving surgery and Targit as a boost to the tumor bed. After lumpectomy, a single dose of 20 Gy was delivered intraoperatively. Postoperative external beam whole-breast radiotherapy excluded the usual boost. We also performed a novel individualized case control (ICC) analysis that computed the expected recurrences for the cohort by estimating the risk of recurrence for each patient using their characteristics and follow-up period. Results: The treatment was well tolerated. The median follow up was 60.5 months (range, 10-122 months). Eight patients have had ipsilateral recurrence: 5-year Kaplan Meier estimate for ipsilateral recurrence is 1.73% (SE 0.77), which compares well with that seen in the boosted patients in the European Organization for Research and Treatment of Cancer study (4.3%) and the UK STAndardisation of breast RadioTherapy study (2.8%). In a novel ICC analysis of 242 of the patients, we estimated that there should be 11.4 recurrences; in this group, only 6 recurrences were observed. Conclusions: Lumpectomy and Targit boost combined with external beam radiotherapy results in a low local recurrence rate in a standard risk patient population. Accurate localization and the immediacy of the treatment that has a favorable effect on tumour microenvironment may contribute to this effect. These long-term data establish the long-term safety and efficacy of the Targit technique and generate the hypothesis that Targit boost might be superior to an external beam boost in its efficacy and justifies a randomized trial.

  6. Efficient technique for calculating multiple solutions of electric-field problems. Part I. Final report

    SciTech Connect

    Lauber, T.S.

    1980-12-01

    The purpose of this report is to present a digital computer program capable of calculating the electrostatic field in an arbitrary two-dimensional configuration. The program was developed as a preliminary result in a project aimed at producing a three-dimensional program. Thus, this report represents an interim report on the entire project.

  7. Field evaluation of a dyed food marking technique for Culex quinquefasciatus (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method of marking adult Cx. quinquefasciatus Say by feeding the larvae commercial hog chow dyed with methylene blue, Giemsa, and crystal violet was evaluated under field conditions. Larvae were offered the dyed food in outdoor basins containg a mixture of dairy effluent and fresh water. Newly emer...

  8. Pulsed-field gel electrophoresis as a discriminatory typing technique for the biothreat agent burkholderia mallei.

    PubMed

    Chantratita, Narisara; Vesaratchavest, Mongkol; Wuthiekanun, Vanaporn; Tiyawisutsri, Rachaneeporn; Ulziitogtokh, Tsedev; Akcay, Erhan; Day, Nicholas P J; Peacock, Sharon J

    2006-03-01

    Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) was used to type 21 laboratory strains of Burkholderia mallei. We demonstrated good resolution by PFGE together with clustering of some geographically related isolates, and confirmed previous observations that B. mallei is clonal as defined by MLST. PMID:16525089

  9. On-combine Sensing Technique for Mapping Straw Yield within Wheat Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Straw from production of wheat is available for conversion to bioenergy. However, not all of this straw is available for conversion because a certain amount must be returned to the soil for conservation. County and state-wide inventories do not account for variation within farm fields. In this st...

  10. Laser-induced fluorescence technique for velocity field measurements in subsonic gas flows

    NASA Technical Reports Server (NTRS)

    Hiller, B.; Mcdaniel, J. C.; Rea, E. C., Jr.; Hanson, R. K.

    1983-01-01

    A nonintrusive optical technique is reported for multiple-point velocity measurements in subsonic flows. The technique is based on the detection of fluorescence from a Doppler-shifted absorption line of seeded iodine molecules excited at a laser frequency fixed in the wing of the line. Counterpropagating laser sheets are used to illuminate the flow, in the present case a nitrogen round jet, thereby eliminating the need for an unshifted reference signal. The fluorescence is detected simultaneously at 10,000 points in a plane of the flow using a 100 x 100 element photodiode-array camera. The velocity at each point is computed from four successive camera frames, each recorded with a different beam direction. The measured mean velocities between 5 and 50 m/sec agree well with data from the literature.

  11. New optical gating technique for detection of electric field waveforms with subpicosecond resolution.

    PubMed

    Muraviev, Andrey; Gutin, Alexey; Rupper, Greg; Rudin, Sergey; Shen, Xiaohan; Yamaguchi, Masashi; Aizin, Gregory; Shur, Michael

    2016-06-13

    The new optical gating technique uses a femtosecond optical laser pulses for the photoconductive detection of short pulses of terahertz (THz) radiation. This technique reproduces the shape of the THz pulse and after pulse plasmonic response of the two-dimensional electron gas in a short channel high electron mobility transistor (HEMT). The results are in excellent agreement with the electro-optic effect measurements and with the simulation results obtained in the frame of a two-dimensional hydrodynamic model. The femtosecond optical laser pulse time is delayed with respect to the THz pulse and generates a large concentration of the electron-hole pairs in the AlGaAs/InGaAs HEMT. This drastically increases the channel conductivity on the femtosecond scale and effectively shorts the device quenching the transistor response. The achieved time resolution is better than 250 femtoseconds and could be improved using shorter femtosecond laser pulses. The spatial resolution of this technique is on the order of tens of nanometers or even smaller. It could be applied for studying the electron transport in a variety of electronic devices ranging from silicon MOSFETs to heterostructure bipolar transistors. PMID:27410292

  12. Application of the windowed-Fourier-transform-based fringe analysis technique for investigating temperature and concentration fields in fluids.

    PubMed

    Mohanan, Sharika; Srivastava, Atul

    2014-04-10

    The present work is concerned with the development and application of a novel fringe analysis technique based on the principles of the windowed-Fourier-transform (WFT) for the determination of temperature and concentration fields from interferometric images for a range of heat and mass transfer applications. Based on the extent of the noise level associated with the experimental data, the technique has been coupled with two different phase unwrapping methods: the Itoh algorithm and the quality guided phase unwrapping technique for phase extraction. In order to generate the experimental data, a range of experiments have been carried out which include cooling of a vertical flat plate in free convection conditions, combustion of mono-propellant flames, and growth of organic as well as inorganic crystals from their aqueous solutions. The flat plate and combustion experiments are modeled as heat transfer applications wherein the interest is to determine the whole-field temperature distribution. Aqueous-solution-based crystal growth experiments are performed to simulate the mass transfer phenomena and the interest is to determine the two-dimensional solute concentration field around the growing crystal. A Mach-Zehnder interferometer has been employed to record the path-integrated quantity of interest (temperature and/or concentration) in the form of interferometric images in the experiments. The potential of the WFT method has also been demonstrated on numerically simulated phase data for varying noise levels, and the accuracy in phase extraction have been quantified in terms of the root mean square errors. Three levels of noise, i.e., 0%, 10%, and 20% have been considered. Results of the present study show that the WFT technique allows an accurate extraction of phase values that can subsequently be converted into two-dimensional temperature and/or concentration distribution fields. Moreover, since WFT is a local processing technique, speckle patterns and the inherent

  13. Evaluating DEM conditioning techniques, elevation source data, and grid resolution for field-scale hydrological parameter extraction

    NASA Astrophysics Data System (ADS)

    Woodrow, Kathryn; Lindsay, John B.; Berg, Aaron A.

    2016-09-01

    Although digital elevation models (DEMs) prove useful for a number of hydrological applications, they are often the end result of numerous processing steps that each contains uncertainty. These uncertainties have the potential to greatly influence DEM quality and to further propagate to DEM-derived attributes including derived surface and near-surface drainage patterns. This research examines the impacts of DEM grid resolution, elevation source data, and conditioning techniques on the spatial and statistical distribution of field-scale hydrological attributes for a 12,000 ha watershed of an agricultural area within southwestern Ontario, Canada. Three conditioning techniques, including depression filling (DF), depression breaching (DB), and stream burning (SB), were examined. The catchments draining to each boundary of 7933 agricultural fields were delineated using the surface drainage patterns modeled from LiDAR data, interpolated to a 1 m, 5 m, and 10 m resolution DEMs, and from a 10 m resolution photogrammetric DEM. The results showed that variation in DEM grid resolution resulted in significant differences in the spatial and statistical distributions of contributing areas and the distributions of downslope flowpath length. Degrading the grid resolution of the LiDAR data from 1 m to 10 m resulted in a disagreement in mapped contributing areas of between 29.4% and 37.3% of the study area, depending on the DEM conditioning technique. The disagreements among the field-scale contributing areas mapped from the 10 m LiDAR DEM and photogrammetric DEM were large, with nearly half of the study area draining to alternate field boundaries. Differences in derived contributing areas and flowpaths among various conditioning techniques increased substantially at finer grid resolutions, with the largest disagreement among mapped contributing areas occurring between the 1 m resolution DB DEM and the SB DEM (37% disagreement) and the DB-DF comparison (36.5% disagreement in mapped

  14. Limitations in paleomagnetic data and modelling techniques and their impact on Holocene geomagnetic field models

    NASA Astrophysics Data System (ADS)

    Panovska, S.; Korte, M.; Finlay, C. C.; Constable, C. G.

    2015-07-01

    Characterization of geomagnetic field behaviour on timescales of centuries to millennia is necessary to understand the mechanisms that sustain the geodynamo and drive its evolution. As Holocene paleomagnetic and archeomagnetic data have become more abundant, strategies for regularized inversion of modern field data have been adapted to produce numerous time-varying global field models. We evaluate the effectiveness of several approaches to inversion and data handling, by assessing both global and regional properties of the resulting models. Global Holocene field models cannot resolve Southern hemisphere regional field variations without the use of sediments. A standard data set is used to construct multiple models using two different strategies for relative paleointensity calibration and declination orientation and a selection of starting models in the inversion procedure. When data uncertainties are considered, the results are similar overall regardless of whether we use iterative calibration and reorientation, or co-estimation of the calibration and orientation parameters as part of the inversion procedure. In each case the quality of the starting model used for initial relative paleointensity calibration and declination orientation is crucial and must be based on the best absolute information available. Without adequate initial calibration the morphology of dipole moment variations can be recovered but its absolute value will be correlated with the initial intensity calibrations, an effect that might be mitigated by ensuring an appropriate fit to enough high quality absolute intensity data with low uncertainties. The declination reorientation mainly impacts regional field structure and in the presence of non-zonal fields will result in a non-zero local average. The importance of declination orientation is highlighted by inconsistencies in the West Pacific and Australian sediment records in CALS10k.1b model. Great care must also be taken to assess uncertainties

  15. Measuring Intuition: Nonconscious Emotional Information Boosts Decision Accuracy and Confidence.

    PubMed

    Lufityanto, Galang; Donkin, Chris; Pearson, Joel

    2016-05-01

    The long-held popular notion of intuition has garnered much attention both academically and popularly. Although most people agree that there is such a phenomenon as intuition, involving emotionally charged, rapid, unconscious processes, little compelling evidence supports this notion. Here, we introduce a technique in which subliminal emotional information is presented to subjects while they make fully conscious sensory decisions. Our behavioral and physiological data, along with evidence-accumulator models, show that nonconscious emotional information can boost accuracy and confidence in a concurrent emotion-free decision task, while also speeding up response times. Moreover, these effects were contingent on the specific predictive arrangement of the nonconscious emotional valence and motion direction in the decisional stimulus. A model that simultaneously accumulates evidence from both physiological skin conductance and conscious decisional information provides an accurate description of the data. These findings support the notion that nonconscious emotions can bias concurrent nonemotional behavior-a process of intuition. PMID:27052557

  16. Fission dynamics within time-dependent Hartree-Fock. II. Boost-induced fission

    NASA Astrophysics Data System (ADS)

    Goddard, Philip; Stevenson, Paul; Rios, Arnau

    2016-01-01

    Background: Nuclear fission is a complex large-amplitude collective decay mode in heavy nuclei. Microscopic density functional studies of fission have previously concentrated on adiabatic approaches based on constrained static calculations ignoring dynamical excitations of the fissioning nucleus and the daughter products. Purpose: We explore the ability of dynamic mean-field methods to describe induced fission processes, using quadrupole boosts in the nuclide 240Pu as an example. Methods: Following upon the work presented in Goddard et al. [Phys. Rev. C 92, 054610 (2015)], 10.1103/PhysRevC.92.054610, quadrupole-constrained Hartree-Fock calculations are used to create a potential energy surface. An isomeric state and a state beyond the second barrier peak are excited by means of instantaneous as well as temporally extended gauge boosts with quadrupole shapes. The subsequent deexcitation is studied in a time-dependent Hartree-Fock simulation, with emphasis on fissioned final states. The corresponding fission fragment mass numbers are studied. Results: In general, the energy deposited by the quadrupole boost is quickly absorbed by the nucleus. In instantaneous boosts, this leads to fast shape rearrangements and violent dynamics that can ultimately lead to fission. This is a qualitatively different process than the deformation-induced fission. Boosts induced within a finite time window excite the system in a relatively gentler way and do induce fission but with a smaller energy deposition. Conclusions: The fission products obtained using boost-induced fission in time-dependent Hartree-Fock are more asymmetric than the fragments obtained in deformation-induced fission or the corresponding adiabatic approaches.

  17. Comparison of molecular and microscopic technique for detection of Theileria annulata from the field cases of cattle

    PubMed Central

    Chauhan, H. C.; Patel, B. K.; Bhagat, A. G.; Patel, M. V.; Patel, S. I.; Raval, S. H.; Panchasara, H. H.; Shrimali, M. D.; Patel, A. C.; Chandel, B. S.

    2015-01-01

    Aim: Tropical theileriosis is fatal hemoprotozoal disease of dairy animals caused by Theileria annulata. The aim of the present study was to detect the T. annulata and comparison of results of molecular and microscopic techniques. Materials and Methods: A total of 52 blood samples were collected from the cattle suspected for theileriosis across the Banaskantha district. All the samples were screened for theileriosis using Giemsa’s staining technique and polymerase chain reaction (PCR). Results: Total of 17 (32.69%) and 24 (46.15%) samples were found positive for theileriosis by microscopic examination and PCR test, respectively. It revealed that the study area is endemic for theileriosis, and the microscopic technique has 70.83% sensitivity and 100% specificity with respect to PCR technique. Conclusion: It may be concluded from the present study that the PCR is comparatively sensitive technique than microscopic examination and may be recommended to use in the field for screening of theileriosis in the study area, where a high prevalence of diseases have been reported due to intensive dairy farming. PMID:27047045

  18. External Magnetic Field Reduction Techniques for the Advanced Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Geng, Steven M.

    2013-01-01

    Linear alternators coupled to high efficiency Stirling engines are strong candidates for thermal-to-electric power conversion in space. However, the magnetic field emissions, both AC and DC, of these permanent magnet excited alternators can interfere with sensitive instrumentation onboard a spacecraft. Effective methods to mitigate the AC and DC electromagnetic interference (EMI) from solenoidal type linear alternators (like that used in the Advanced Stirling Convertor) have been developed for potential use in the Advanced Stirling Radioisotope Generator. The methods developed avoid the complexity and extra mass inherent in data extraction from multiple sensors or the use of shielding. This paper discusses these methods, and also provides experimental data obtained during breadboard testing of both AC and DC external magnetic field devices.

  19. Research of Arc Chamber Optimization Techniques Based on Flow Field and Arc Joint Simulation

    NASA Astrophysics Data System (ADS)

    Zhong, Jianying; Guo, Yujing; Zhang, Hao

    2016-03-01

    The preliminary design of an arc chamber in the 550 kV SF6 circuit breaker was proposed in accordance with the technical requirements and design experience. The structural optimization was carried out according to the no-load flow field simulation results and verified by no-load pressure measurement. Based on load simulation results such as temperature field variation at the arc area and the tendency of post arc current under different recovery voltage, the second optimal design was completed and its correctness was certificated by a breaking test. Results demonstrate that the interrupting capacity of an arc chamber can be evaluated by the comparison of the gas medium recovery speed and post arc current growth rate.

  20. A hybrid numerical technique for predicting the aerodynamic and acoustic fields of advanced turboprops

    NASA Technical Reports Server (NTRS)

    Homicz, G. F.; Moselle, J. R.

    1985-01-01

    A hybrid numerical procedure is presented for the prediction of the aerodynamic and acoustic performance of advanced turboprops. A hybrid scheme is proposed which in principle leads to a consistent simultaneous prediction of both fields. In the inner flow a finite difference method, the Approximate-Factorization Alternating-Direction-Implicit (ADI) scheme, is used to solve the nonlinear Euler equations. In the outer flow the linearized acoustic equations are solved via a Boundary-Integral Equation (BIE) method. The two solutions are iteratively matched across a fictitious interface in the flow so as to maintain continuity. At convergence the resulting aerodynamic load prediction will automatically satisfy the appropriate free-field boundary conditions at the edge of the finite difference grid, while the acoustic predictions will reflect the back-reaction of the radiated field on the magnitude of the loading source terms, as well as refractive effects in the inner flow. The equations and logic needed to match the two solutions are developed and the computer program implementing the procedure is described. Unfortunately, no converged solutions were obtained, due to unexpectedly large running times. The reasons for this are discussed and several means to alleviate the situation are suggested.

  1. Identification of vibration excitations from acoustic measurements using near field acoustic holography and the force analysis technique

    NASA Astrophysics Data System (ADS)

    Pézerat, C.; Leclère, Q.; Totaro, N.; Pachebat, M.

    2009-10-01

    This study presents a method of using acoustic holography and the force analysis technique to identify vibration sources from radiated noise measurements. The structure studied is a plate excited by a shaker on which three measurements were performed: the first is a reference measurement of plate velocity obtained by scanning laser vibrometry, the second is based on sound pressure measurements in the near field of the structure, and the third is the measurement of normal acoustic velocities by using a p-U probe recently developed by Microflown Technologies. This was followed by the application of classical NAH, known as pressure-to-velocity holography and velocity-to-velocity holography to predict the plate velocity field from acoustic measurements at distances of 1 and 5 cm. Afterwards, the force analysis technique, also known as the RIFF technique, is applied with these five data sets. The principle is to inject the displacement field of the structure into its equation of motion and extract the resulting force distribution. This technique requires regularization done by a low-pass filter in the wavenumber domain. Apart from pressure-to-velocity holography at 5 cm, the reconstructed force distribution allows localizing the excitation point in the measurement area. FAT regularization is also shown to improve results as its cutoff wavenumber is optimized with the natural wavenumber of the plate. Lastly, quantitative force values are extracted from force distributions at all frequencies of the band 0-4 kHz studied and compared with the force spectrum measured directly by a piezoelectric sensor.

  2. Reevaluation of indirect field stimulation technique to demonstrate oxime effectiveness in OP-poisoning in muscles in vitro.

    PubMed

    Seeger, T; Worek, F; Szinicz, L; Thiermann, H

    2007-04-20

    Organophosphorus (OP) pesticides or nerve agents cause severe intoxication by inhibition of acetylcholinesterase, finally resulting in death due to respiratory failure. The phrenic nerve diaphragm preparation is considered as the classic model to investigate the effect of OP intoxications and oxime treatment at the neuromuscular junction. However, this preparation is unsuitable for larger species or for muscle strips from biopsies where no nerve is available for stimulation. An alternative technique is the indirect field stimulation of muscles containing intramuscular nerve branches only. The proposed method by Wolthuis et al. [Wolthuis, O.L., Vanwersch, R.A.P., Van Der Wiel, H.J., 1981. The efficacy of some bis-pyridinium oximes as antidotes to soman in isolated muscles of several species including man. Eur. J. Pharmacol. 70, 355-369] was modified and experimentally reevaluated in isolated mouse diaphragms. To confirm that electrical field stimulation technique induced muscle contraction only via the neuromuscular endplate the nicotinic antagonists pancuronium or d-tubocurarine (1microM) were given. In the presence of a nicotinic antagonist hardly any contraction was blocked after indirect field stimulation technique with very short pulses (5micros, <0.6A), in contrast to direct muscle stimulation (broader pulse width, or higher amplitude >0.6A). During paraoxon circumfusion (20min, 1micromol/l) muscle force generation by indirect stimulation was almost completely blocked. Restoration of paralyzed muscle function to 80% of initial values could be achieved after paraoxon wash out (20min) and circumfusion with obidoxime (1micromol/l, 20min). This data correspond quite well to data shown earlier when using conventional nerve stimulation techniques. PMID:17250944

  3. Full-field speckle correlation technique as applied to blood flow monitoring

    NASA Astrophysics Data System (ADS)

    Vilensky, M. A.; Agafonov, D. N.; Timoshina, P. A.; Shipovskaya, O. V.; Zimnyakov, D. A.; Tuchin, V. V.; Novikov, P. A.

    2011-03-01

    The results of experimental study of monitoring the microcirculation in tissue superficial layers of the internal organs at gastro-duodenal hemorrhage with the use of laser speckles contrast analysis technique are presented. The microcirculation monitoring was provided in the course of the laparotomy of rat abdominal cavity in the real time. Microscopic hemodynamics was analyzed for small intestine and stomach under different conditions (normal state, provoked ischemia, administration of vasodilative agents such as papaverine, lidocaine). The prospects and problems of internal monitoring of micro-vascular flow in clinical conditions are discussed.

  4. Numerical spatial marching techniques in duct acoustics. [noise source calculation from far field pressure measurements

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.

    1979-01-01

    Direct calculation of the internal structure of a ducted noise source from farfield pressure measurements is regarded as an initial value problem, where the pressure and pressure gradient (farfield impedance) are assumed to be known along a line in the farfield. If pressure and impedance are known at the boundary of the farfield, the pressure can be uniquely determined in the vicinity of the inlet and inside the inlet ducting. A marching procedure is developed which, with this information obtained from measurements, enables a description of a ducted noise source. The technique uses a finite difference representation of the homogeneous Helmholtz equation.

  5. A novel polymer-free transfer technique for high mobility graphene field effect transistors (FET)

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Hsiang; Liu, Shang-Yi; Hsu, Chen-Chi; Taur, Jieh-I.; Boyd, David A.; Wu, Chih-I.; Yeh, Nai-Chang; Chih-I Wu Collaboration; Nai-Chang Yeh Team

    2014-03-01

    We demonstrate a novel polymer-free method that can routinely transfer large-area graphene to any substrates and preserve the optimal properties of as-grown samples as compared to the graphene transferred with conventional polymer-assisted methods. We have also developed a one-step method that employs plasma-enhanced chemical vapor deposition for rapidly producing superior quality, large-area, monolayer graphene on Cu at low temperature (LT). Combining these two techniques, we find excellent properties of the LT-CVD grown graphene based on studies of Raman spectroscopy, XPS, UPS and STM. We have also investigated the effect of various substrates and PMMA residuals on the performance of the LT-CVD grown graphene FETs by constructing four types of devices (graphene/SiO2 FETs, graphene/BN FETs, PMMA residuals/ graphene/SiO2 FETs, and PMMA residuals/graphene/BN FETs). The LT-CVD grown graphene combined with the polymer-free transfer technique has achieved an electrical mobility ~ 60,000 cm2 V-1 s-1, which may be further improved to approaching the ideal value of pristine graphene. Work supported by NSF under the IQIM at Caltech and NSC in Taiwan.

  6. Applying additive modeling and gradient boosting to assess the effects of watershed and reach characteristics on riverine assemblages

    USGS Publications Warehouse

    Maloney, Kelly O.; Schmid, Matthias; Weller, Donald E.

    2012-01-01

    Issues with ecological data (e.g. non-normality of errors, nonlinear relationships and autocorrelation of variables) and modelling (e.g. overfitting, variable selection and prediction) complicate regression analyses in ecology. Flexible models, such as generalized additive models (GAMs), can address data issues, and machine learning techniques (e.g. gradient boosting) can help resolve modelling issues. Gradient boosted GAMs do both. Here, we illustrate the advantages of this technique using data on benthic macroinvertebrates and fish from 1573 small streams in Maryland, USA.

  7. Writing about testing worries boosts exam performance in the classroom.

    PubMed

    Ramirez, Gerardo; Beilock, Sian L

    2011-01-14

    Two laboratory and two randomized field experiments tested a psychological intervention designed to improve students' scores on high-stakes exams and to increase our understanding of why pressure-filled exam situations undermine some students' performance. We expected that sitting for an important exam leads to worries about the situation and its consequences that undermine test performance. We tested whether having students write down their thoughts about an upcoming test could improve test performance. The intervention, a brief expressive writing assignment that occurred immediately before taking an important test, significantly improved students' exam scores, especially for students habitually anxious about test taking. Simply writing about one's worries before a high-stakes exam can boost test scores. PMID:21233387

  8. Effect of nonlinear absorption on electric field applied lead chloride by Z-scan technique

    NASA Astrophysics Data System (ADS)

    Rejeena, I.; Lillibai, Rahimkutty, M. H.; Nampoori, V. P. N.; Radhakrishnan, P.

    2014-10-01

    The preparation, spectral response and optical nonlinearity of gel grown lead chloride single crystals subjected to electric field of 20V using parallel plate arrangements have been investigated. Optical band gap of the samples were determined using linear absorption spectra. Open aperture z-scan was employed for the determination of nonlinear absorption coefficient of PbCl2 solution. The normalized transmittance curve exhibits a valley shows reverse saturable absorption. The non linear absorption at different input fluences were recorded using a single Gaussian laser beam in tight focus geometry. The RSA nature of the sample makes it suitable for optical limiting applications.

  9. Measurements of solar magnetic fields by Fourier transform techniques. I - Unsaturated lines

    NASA Technical Reports Server (NTRS)

    Title, A. M.; Tarbell, T. D.

    1975-01-01

    If the basic profile shapes of the normal Zeeman triplet do not have zeros in their Fourier transform, the magnetic field splitting can be determined independent of the profile shape. When the ratio of the splitting of the components is greater than the intrinsic FWHM of the component profiles, the magnetic splitting can be determined with significantly greater accuracy than the measurement accuracy of the original profile. For Gaussian shaped components and a ratio of magnetic splitting to FWHM of 1.5, the noise reduction factor is 25.

  10. Effect of nonlinear absorption on electric field applied lead chloride by Z-scan technique

    SciTech Connect

    Rejeena, I.; Lillibai,; Nampoori, V. P. N.; Radhakrishnan, P.; Rahimkutty, M. H.

    2014-10-15

    The preparation, spectral response and optical nonlinearity of gel grown lead chloride single crystals subjected to electric field of 20V using parallel plate arrangements have been investigated. Optical band gap of the samples were determined using linear absorption spectra. Open aperture z-scan was employed for the determination of nonlinear absorption coefficient of PbCl{sub 2} solution. The normalized transmittance curve exhibits a valley shows reverse saturable absorption. The non linear absorption at different input fluences were recorded using a single Gaussian laser beam in tight focus geometry. The RSA nature of the sample makes it suitable for optical limiting applications.

  11. A hybrid experimental-numerical technique for determining 3D velocity fields from planar 2D PIV data

    NASA Astrophysics Data System (ADS)

    Eden, A.; Sigurdson, M.; Mezić, I.; Meinhart, C. D.

    2016-09-01

    Knowledge of 3D, three component velocity fields is central to the understanding and development of effective microfluidic devices for lab-on-chip mixing applications. In this paper we present a hybrid experimental-numerical method for the generation of 3D flow information from 2D particle image velocimetry (PIV) experimental data and finite element simulations of an alternating current electrothermal (ACET) micromixer. A numerical least-squares optimization algorithm is applied to a theory-based 3D multiphysics simulation in conjunction with 2D PIV data to generate an improved estimation of the steady state velocity field. This 3D velocity field can be used to assess mixing phenomena more accurately than would be possible through simulation alone. Our technique can also be used to estimate uncertain quantities in experimental situations by fitting the gathered field data to a simulated physical model. The optimization algorithm reduced the root-mean-squared difference between the experimental and simulated velocity fields in the target region by more than a factor of 4, resulting in an average error less than 12% of the average velocity magnitude.

  12. Enhanced adhesion and field emission of CuO nanowires synthesized by simply modified thermal oxidation technique.

    PubMed

    Tang, C M; Wang, Y B; Yao, R H; Ning, H L; Qiu, W Q; Liu, Z W

    2016-09-30

    Metal oxide nanowires (NWs) can be easily grown by the thermal oxidation method, but the low adhesion between the NWs and the substrate restricts their practical applications in functional devices. In this work, the conventional hotplate technique is simply modified by introducing one or two stainless steel plates to supply a more stable oxidation environment, which is found to be beneficial to the growth and adhesion of CuO NWs on the Cu substrate. In detail, the Cu foils were heated on the hotplate directly, on one plate over the hotplate, and between two plates over the hotplate at 400 °C in ambient condition. It is found that the NWs obtained between two plates exhibit large length and diameter with moderate density. The sufficient activated oxygen, stable temperature, and proper temperature gradient configuration caused by the two plates accelerate the formation of CuO NWs, and result in the longest NWs with enhanced adhesion. The grain-boundary diffusion and Kirkendall effect are proposed to explain the mechanism of NWs growth and the formation of cracks. The NWs obtained between two plates also showed the best field emission properties, with lowest turn-on field (5.31 V μm(-1)) and threshold field (9.8 V μm(-1)). Excellent field emission properties and enhanced NW-substrate adhesion indicate that these NW arrays could be potentially used as the cathode of field emission displays. PMID:27560484

  13. New beam-tracking simulation code using bulk-to-point calculation technique for space charge fields

    NASA Astrophysics Data System (ADS)

    Mizuno, A.

    2016-02-01

    A new two-dimensional beam-tracking simulation code for electron injectors using a bulk-to-point calculation technique for space charge fields was developed. The calculated space charge fields are produced not by a point charge but by a hollow cylinder that has a volume. Each tracked electron is a point charge. This bulk-to-point calculation technique for space charge fields is based on that used in the multiple beam envelope equations, which were developed by the author. The multiple beam envelope equations are a set of differential equations for investigating the beam dynamics of electron injectors and can be used to calculate bunched beam dynamics with high accuracy. However, there is one limitation. The bunched beam is assumed to be an ensemble of several segmentation pieces in both the transverse and longitudinal directions. In this bunch model, each longitudinal segmentation slice in a bunch must not warp; consequently, the accuracy of the calculated emittance is reduced in the case of a highly charged beam for calculations of a typical rf gun injector system. This limitation is related to the calculation model of longitudinal space charge fields. In the newly developed beam-tracking simulation code, the space charge field calculation scheme is upgraded and the limitation has been overcome. Therefore, the applicable range is extended while maintaining the high accuracy of emittance calculations. Simultaneously, the calculation time is markedly shortened because the emittance dependence on the segmentation number is extremely weak. In this paper, several examples of beam dynamics that cannot be calculated accurately using the multiple beam envelope equations are demonstrated using the new beam-tracking simulation code. The accuracy of the calculated emittance is also discussed.

  14. Progress Toward a Technique for Measuring Electric Field Fluctuations in Tokamak Core Plasmas

    NASA Astrophysics Data System (ADS)

    Thompson, D. S.; Bakken, M. R.; Burke, M. G.; Couto, H. P.; Fonck, R. J.; Lewicki, B. T.; Winz, G. R.

    2014-10-01

    Measurements of electric field fluctuations in magnetic confinement experiments are desired for validating turbulence and transport models. A new diagnostic to measure Ez (r , t) fluctuations is in development on the Pegasus Toroidal Experiment. The approach is based on neutral beam emission spectroscopy using a high-throughput, high-resolution spectrometer to resolve fluctuations in wavelength separation between components of the motional Stark effect spectrum. Fluctuations at mid-minor-radius, normalized to an estimated MSE field, are estimated to be δE /EMSE ~ 10-3. In order to resolve fluctuations at turbulent time scales (fNy ~ 500 kHz), beam and spectrometer designs minimize broadening and maximize signal-to-noise ratio. The diagnostic employs a Fabry-Pérot spectrometer with étendue-matched collection optics and low noise detectors. The interferometer spacing is varied across the face of the etalon to mitigate geometric Doppler broadening. An 80 keV H0 beam from PBX-M with a divergence Ω < 0.5 degrees is being refurbished for this project. The beam includes a new ion source to maximize full energy species fraction and is designed to provide ~ 2 cm spatial resolution and 50 ms of 6 mA/cm2current density at the focal plane. Successful development and demonstration on Pegasus will guide future deployment on larger fusion facilities. Work supported by US DOE Grant DE-FG02-89ER53296.

  15. The Topography of Visuospatial Attention as Revealed by a Novel Visual Field Mapping Technique

    PubMed Central

    Brefczynski-Lewis, Julie A.; Datta, Ritobrato; Lewis, James W.; DeYoe, Edgar A.

    2009-01-01

    Previously, we and others have shown that attention can enhance visual processing in a spatially specific manner that is retinotopically mapped in the occipital cortex. However, it is difficult to appreciate the functional significance of the spatial pattern of cortical activation just by examining the brain maps. In this study, we visualize the neural representation of the “spotlight” of attention using a back-projection of attention-related brain activation onto a diagram of the visual field. In the two main experiments, we examine the topography of attentional activation in the occipital and parietal cortices. In retinotopic areas, attentional enhancement is strongest at the locations of the attended target, but also spreads to nearby locations and even weakly to restricted locations in the opposite visual field. The dispersion of attentional effects around an attended site increases with the eccentricity of the target in a manner that roughly corresponds to a constant area of spread within the cortex. When averaged across multiple observers, these patterns appear consistent with a gradient model of spatial attention. However, individual observers exhibit complex variations that are unique but reproducible. Overall, these results suggest that the topography of visual attention for each individual is composed of a common theme plus a personal variation that may reflect their own unique “attentional style.” PMID:18752412

  16. Different magnitude representations in left and right hemisphere: evidence from the visual half field technique.

    PubMed

    Notebaert, Karolien; Reynvoet, Bert

    2009-05-01

    The differences between left and right hemispheric magnitude representations were investigated in two lateralised priming experiments using single-digit (Experiment 1) and two-digit numbers (Experiment 2). Based on recent brain-imaging and TMS studies, some authors have argued that the magnitude representation in the left hemisphere (LH) is more precise than the one in the right hemisphere (RH). In two experiments a prime number preceded a target number that had to be classified as smaller or larger than a fixed standard. In order to reveal hemispheric differences in magnitude representation, the priming distance effect, i.e., faster responses to targets preceded by numerically closer primes, was analysed in both visual half fields (VHF). Using single-digit numbers no hemispheric differences were found for the priming distance effect, supporting an equally precise magnitude representation in both hemispheres. However, the experiment using two-digit numbers revealed a significantly steeper priming curve when targets were presented in the left visual field (LVF) compared to targets presented in the RVF. These results suggest a less precise magnitude representation in the RH, due to a larger overlap of magnitude representations. PMID:18792837

  17. Noncontact measurement of liquid-surface properties with knife-edge electric field tweezers technique

    NASA Astrophysics Data System (ADS)

    Shimokawa, Yuji; Sakai, Keiji

    2013-06-01

    We have developed a technique for the simultaneous measurement of the surface tension and the viscosity of a liquid in a noncontact manner. In this method, a small linear deformation of the liquid surface is induced by a local dielectric force that is brought about by a knife-edge electrode. The surface tension and the viscosity are obtained from the shape of the induced meniscus and from the dynamic response of the surface, respectively. The surface tension obtained was examined in comparison with the values measured by the Wilhelmy plate method. We also measured time constants of the surface deformation for a variety of standard viscosity samples and obtained the relation between the time constant and the viscosity. The demonstrated advantage of the system is the ability to uniquely determine the surface tension and the viscosity.

  18. Noncontact measurement of liquid-surface properties with knife-edge electric field tweezers technique.

    PubMed

    Shimokawa, Yuji; Sakai, Keiji

    2013-06-01

    We have developed a technique for the simultaneous measurement of the surface tension and the viscosity of a liquid in a noncontact manner. In this method, a small linear deformation of the liquid surface is induced by a local dielectric force that is brought about by a knife-edge electrode. The surface tension and the viscosity are obtained from the shape of the induced meniscus and from the dynamic response of the surface, respectively. The surface tension obtained was examined in comparison with the values measured by the Wilhelmy plate method. We also measured time constants of the surface deformation for a variety of standard viscosity samples and obtained the relation between the time constant and the viscosity. The demonstrated advantage of the system is the ability to uniquely determine the surface tension and the viscosity. PMID:23848774

  19. Comparison of different MC techniques to evaluate BNCT dose profiles in phantom exposed tovarious neutron fields.

    PubMed

    Durisi, E; Koivunoro, H; Visca, L; Borla, O; Zanini, A

    2010-03-01

    The absorbed dose in BNCT (boron neutron capture therapy) consists of several radiation components with different physical properties and biological effectiveness. In order to assess the clinical efficacy of the beams, determining the dose profiles in tissues, Monte Carlo (MC) simulations are used. This paper presents a comparison between dose profiles calculated in different phantoms using two techniques: MC radiation transport code, MCNP-4C2 and BNCT MC treatment planning program, SERA (simulation environment for radiotherapy application). In this study MCNP is used as a reference tool. A preliminary test of SERA is performed using six monodirectional and monoenergetic beams directed onto a simple water phantom. In order to deeply investigate the effect of the different cross-section libraries and of the dose calculation methodology, monoenergetic and monodirectional beams directed toward a standard Snyder phantom are simulated. Neutron attenuation curves and dose profiles are calculated with both codes and the results are compared. PMID:19939825

  20. Fielding the magnetically applied pressure-shear technique on the Z accelerator (completion report for MRT 4519).

    SciTech Connect

    Alexander, C. Scott; Haill, Thomas A.; Dalton, Devon Gardner; Rovang, Dean Curtis; Lamppa, Derek C.

    2013-09-01

    The recently developed Magnetically Applied Pressure-Shear (MAPS) experimental technique to measure material shear strength at high pressures on magneto-hydrodynamic (MHD) drive pulsed power platforms was fielded on August 16, 2013 on shot Z2544 utilizing hardware set A0283A. Several technical and engineering challenges were overcome in the process leading to the attempt to measure the dynamic strength of NNSA Ta at 50 GPa. The MAPS technique relies on the ability to apply an external magnetic field properly aligned and time correlated with the MHD pulse. The load design had to be modified to accommodate the external field coils and additional support was required to manage stresses from the pulsed magnets. Further, this represents the first time transverse velocity interferometry has been applied to diagnose a shot at Z. All subsystems performed well with only minor issues related to the new feed design which can be easily addressed by modifying the current pulse shape. Despite the success of each new component, the experiment failed to measure strength in the samples due to spallation failure, most likely in the diamond anvils. To address this issue, hydrocode simulations are being used to evaluate a modified design using LiF windows to minimize tension in the diamond and prevent spall. Another option to eliminate the diamond material from the experiment is also being investigated.

  1. Mini-FLOTAC, an Innovative Direct Diagnostic Technique for Intestinal Parasitic Infections: Experience from the Field

    PubMed Central

    Barda, Beatrice Divina; Rinaldi, Laura; Ianniello, Davide; Zepherine, Henry; Salvo, Fulvio; Sadutshang, Tsetan; Cringoli, Giuseppe; Clementi, Massimo; Albonico, Marco

    2013-01-01

    Background Soil-transmitted helminths and intestinal protozoa infection are widespread in developing countries, yet an accurate diagnosis is rarely performed. The aim of this study was to evaluate the recently developed mini–FLOTAC method and to compare with currently more widely used techniques for the diagnosis of intestinal parasitic infections in different settings. Methodology/Principal Findings The study was carried out in Dharamsala, Himachal Pradesh, India, and in Bukumbi, Tanzania. A total of 180 pupils from two primary schools had their stool analyzed (n = 80 in Dharamsala and n = 100 in Bukumbi) for intestinal parasitic infections with three diagnostic methods: direct fecal smear, formol-ether concentration method (FECM) and mini-FLOTAC. Overall, 72% of the pupils were positive for any intestinal parasitic infection, 24% carried dual infections and 11% three infections or more. The most frequently encountered intestinal parasites were Entamoeba coli, Entamoeba histolytica/dispar, Giardia intestinalis, hookworm, (and Schistosoma mansoni, in Tanzania). Statistically significant differences were found in the detection of parasitic infections among the three methods: mini-FLOTAC was the most sensitive method for helminth infections (90% mini-FLOTAC, 60% FECM, and 30% direct fecal smear), whereas FECM was most sensitive for intestinal protozoa infections (88% FECM, 70% direct fecal smear, and 68% mini-FLOTAC). Conclusion/Significance We present the first experiences with the mini-FLOTAC for the diagnosis of intestinal helminths and protozoa. Our results suggest that it is a valid, sensitive and potentially low-cost alternative technique that could be used in resource-limited settings — particularly for helminth diagnosis. PMID:23936577

  2. Direct observation of λ-DNA molecule reversal movement within microfluidic channels under electric field with single molecule imaging technique

    NASA Astrophysics Data System (ADS)

    Fengyun, Yang; Kaige, Wang; Dan, Sun; Wei, Zhao; Hai-qing, Wang; Xin, He; Gui-ren, Wang; Jin-tao, Bai

    2016-07-01

    The electrodynamic characteristics of single DNA molecules moving within micro-/nano-fluidic channels are important in the design of biomedical chips and bimolecular sensors. In this study, the dynamic properties of λ-DNA molecules transferring along the microchannels driven by the external electrickinetic force were systemically investigated with the single molecule fluorescence imaging technique. The experimental results indicated that the velocity of DNA molecules was strictly dependent on the value of the applied electric field and the diameter of the channel. The larger the external electric field, the larger the velocity, and the more significant deformation of DNA molecules. More meaningfully, it was found that the moving directions of DNA molecules had two completely different directions: (i) along the direction of the external electric field, when the electric field intensity was smaller than a certain threshold value; (ii) opposite to the direction of the external electric field, when the electric field intensity was greater than the threshold electric field intensity. The reversal movement of DNA molecules was mainly determined by the competition between the electrophoresis force and the influence of electro-osmosis flow. These new findings will theoretically guide the practical application of fluidic channel sensors and lab-on-chips for precisely manipulating single DNA molecules. Project supported by the National Natural Science Foundation of China (Grant No. 61378083), the International Cooperation Foundation of the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011DFA12220), the Major Research Plan of National Natural Science Foundation of China (Grant No. 91123030), and the Natural Science Foundation of Shaanxi Province of China (Grant Nos. 2010JS110 and 2013SZS03-Z01).

  3. Redox and speciation mapping of rock thin sections using high spatial resolution full-field imaging technique

    NASA Astrophysics Data System (ADS)

    de Andrade, V.; Susini, J.; Salomé, M.; Beraldin, O.; Heymes, T.; Lewin, E.

    2009-04-01

    Because of their complex genesis, natural rocks are the most often heterogeneous systems, with various scale-level heterogeneities for both chemistry and structure. In the last decade, the dramatic improvements of hyperspectral imaging techniques provided new tools for accurate material characterisation. Most of these micro- and nano- analytical techniques rely on scanning instruments, which offer high spatial resolution but suffer from long acquisition times imposing practical limits on the field of view. Conversely, full-field imaging techniques rely on a fast parallel acquisition but have limited resolution. Although soft X-ray full-field microscopes based on Fresnel zone plates are commonly used for high resolution imaging, its combination with spectroscopy is challenging and 2D chemical mapping still difficult. For harder X-rays, lensless X-ray microscope based on simple propagation geometry is easier and can be readily used for 2D spectro-microscopy. A full-field experimental setup was optimized at the ESRF-ID21 beamline to image iron redox and speciation distributions in rocks thin sections. The setup comprises a Si111 or Si220 (E = 0.4 eV) monochromator, a special sample stage and a sensitive camera associated with a brand new GGG:Eu light conversion scintillator and high magnification visible light optics. The pixel size ranges from 1.6 to 0.16 m according to the optic used. This instrument was used to analyse phyllosilicates and oxides of metamorphic sediments coming from the Aspromonte nappes-pile in Calabria. Iron chemical state distributions were derived - from images of 1000 Ã- 2000 Ã- 30 m3 rock thin sections - by subtraction of absorption images above and below the Fe K-edge. Using an automatic stitching reconstruction, a wide field image (4Ã-3 mm2 with a 1 m2 resolution for a total of about 12 millions pixels) of Fetotal elemental distribution was produced. Moreover, -XANES analyses (more than 1 million individual -XANES spectra) were performed

  4. Sublacustrine groundwater discharge in esker aquifers; fully integrated groundwater flow modeling compared with novel field techniques

    NASA Astrophysics Data System (ADS)

    Ala-aho, Pertti; Rossi, Pekka M.; Isokangas, Elina; Kløve, Bjørn

    2015-04-01

    Groundwater (GW) discharge to surface water bodies such as streams, lakes and wetlands can greatly affect their water quantity, quality and related aquatic ecology. Therefore better understanding of GW - surface water interaction is needed in integrated management of water resources. Sublacustrine groundwater discharge (SGD) to lakes was studied in a complex unconfined Rokua esker aquifer system. SGD was studied for 12 lakes in the area to better understand water and solute inputs through lake beds and thereby the role of GW on lake water budget and solute concentrations. The locations and fluxes of SGD were simulated using a fully integrated groundwater flow model HydroGeoSphere. The used hydrological simulator allows water to flow and partition into overland and stream flow, evaporation, infiltration, and subsurface discharge into surface water features in a physically-based way, which was needed in simulating SGD of the complex aquifer system. The model was first calibrated for subsurface hydraulic conductivity in steady state using data of measured long-term average groundwater and lake levels and stream baseflow. The model performance in transient simulations was then examined against recorded hydrographs for lake and groundwater levels and stream flow. After model performance was verified, the simulated locations and fluxes of SGD were extracted from the model and compared with results from three independent field methods: airborne thermal imaging, stable isotope water balance and seepage meter measurements. Airborne thermal imaging was used to infer locations of SGD into lakes based on temperature anomalies at lakes shorelines due to discharging cold groundwater. Isotopic composition (H2 and O18) was analysed for lake water, groundwater and the data was used to estimate SGD flux into lakes. Finally, seepage meter measurements were conducted for one of the lakes to establish both locations and fluxes of SGD in detail. The simulated and field-based estimated

  5. Electron-beam manipulation techniques in the SINBAD Linac for external injection in plasma wake-field acceleration

    NASA Astrophysics Data System (ADS)

    Marchetti, B.; Assmann, R.; Behrens, C.; Brinkmann, R.; Dorda, U.; Floettmann, K.; Hartl, I.; Huening, M.; Nie, Y.; Schlarb, H.; Zhu, J.

    2016-09-01

    The SINBAD facility (Short and INnovative Bunches and Accelerators at Desy) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration techniques. Besides studying novel acceleration techniques aiming to produce high brightness short electron bunches, the ARD group at DESY is working on the design of a conventional RF accelerator that will allow the production of low charge (0.5 pC - few pC) ultra-short electron bunches (having full width half maximum, FWHM, length ≤ 1 fs - few fs). The setup will allow the direct experimental comparison of the performance achievable by using different compression techniques (velocity bunching, magnetic compression, hybrid compression schemes). At a later stage the SINBAD linac will be used to inject such electron bunches into a laser driven Plasma Wakefield Accelerator, which imposes strong requirements on parameters such as the arrival time jitter and the pointing stability of the beam. In this paper we review the compression techniques that are foreseen at SINBAD and we underline the differences in terms of peak current, beam quality and arrival time stability.

  6. Complementary use of flow and sedimentation field-flow fractionation techniques for size characterizing biodegradable poly(lactic acid) nanospheres

    PubMed Central

    Contado, Catia; Dalpiaz, Alessandro; Leo, Eliana; Zborowski, Maciej; Williams, P. Stephen

    2009-01-01

    Poly(lactic acid) nanoparticles were synthesized using a modified evaporation method, testing two different surfactants (sodium cholate and Pluronic F68) for the process. During their formulation the prodrug 5′-octanoyl-CPA (Oct-CPA) of the antiischemic N6-cyclopentyladenosine (CPA) was encapsulated. Three different purification methods were compared with respect to the influence of surfactant on the size characteristics of the final nanoparticle product. Flow and sedimentation field-flow fractionation techniques (FlFFF and SdFFF, respectively) were used to size characterize the five poly(lactic acid) particle samples. Two different combinations of carrier solution (mobile phase) were employed in the FlFFF analyses, while a solution of poly(vinyl alcohol) was used as mobile phase for the SdFFF runs. The separation performances of the two techniques were compared and the particle size distributions, derived from the fractograms, were interpreted with the support of observations by scanning electron microscopy. Some critical aspects, such as the carrier choice and the channel thickness determination for the FlFFF, have been investigated. This is the first comprehensive comparison of the two FFF techniques for characterizing non standard particulate materials. The two FFF techniques proved to be complementary and gave good, congruent and very useful information on the size distributions of the five poly(lactic acid) particle samples. PMID:17482199

  7. Organic nanofibers integrated by transfer technique in field-effect transistor devices

    PubMed Central

    2011-01-01

    The electrical properties of self-assembled organic crystalline nanofibers are studied by integrating these on field-effect transistor platforms using both top and bottom contact configurations. In the staggered geometries, where the nanofibers are sandwiched between the gate and the source-drain electrodes, a better electrical conduction is observed when compared to the coplanar geometry where the nanofibers are placed over the gate and the source-drain electrodes. Qualitatively different output characteristics were observed for top and bottom contact devices reflecting the significantly different contact resistances. Bottom contact devices are dominated by contact effects, while the top contact device characteristics are determined by the nanofiber bulk properties. It is found that the contact resistance is lower for crystalline nanofibers when compared to amorphous thin films. These results shed light on the charge injection and transport properties for such organic nanostructures and thus constitute a significant step forward toward a nanofiber-based light-emitting device. PMID:21711821

  8. A measurement technique for circumventing hysteresis and conductance drift in carbon nanotube field-effect transistors

    NASA Astrophysics Data System (ADS)

    Tunnell, Andrew; Ballarotto, Vincent; Cumings, John

    2014-01-01

    We present a measurement protocol that effectively eliminates both the hysteresis and the temporal drift typically observed in the channel conductance of single-walled carbon nanotube field-effect transistors (SWNT FETs) during the application of gate voltages. Before each resistance measurement, the gate is first stepped through a series of alternating positive and negative voltages to produce a neutral charge distribution within the device. This process is highly effective at removing the hysteresis in the channel conductance, and time-dependent measurements further demonstrate that the drain current is stable and single-valued, independent of the prior measurement history. The effectiveness of this method can be understood within the Preisach hysteresis model, which we demonstrate as a useful framework to predict the observed results.

  9. A measurement technique for circumventing hysteresis and conductance drift in carbon nanotube field-effect transistors.

    PubMed

    Tunnell, Andrew; Ballarotto, Vincent; Cumings, John

    2014-01-31

    We present a measurement protocol that effectively eliminates both the hysteresis and the temporal drift typically observed in the channel conductance of single-walled carbon nanotube field-effect transistors (SWNT FETs) during the application of gate voltages. Before each resistance measurement, the gate is first stepped through a series of alternating positive and negative voltages to produce a neutral charge distribution within the device. This process is highly effective at removing the hysteresis in the channel conductance, and time-dependent measurements further demonstrate that the drain current is stable and single-valued, independent of the prior measurement history. The effectiveness of this method can be understood within the Preisach hysteresis model, which we demonstrate as a useful framework to predict the observed results. PMID:24394672

  10. Field investigation of techniques for remote laser sensing of oceanographic parameters

    NASA Technical Reports Server (NTRS)

    Houghton, W. M.; Exton, R. J.; Gregory, R. W.

    1983-01-01

    A laser fluorosensor, previously studied in the laboratory, was deployed at a pier in lower Chesapeake Bay for field testing. A Q-switched Nd:YAG laser doubled to 532 nm in conjunction with a gated optical multichannel analyzer (OMA) allow spectra with high signal-to-noise ratios to be recorded in full daylight at a distance of 20 m. As a test of the system a study was conducted of the spatial and temporal variations of the phytopigments phycoerythrin and chlorophyll. The phycoerythrin feature was resolved into two components, one attributable to cyanophytes and the other to cryptophytes. A comparison was also made with spectra obtained by the NASA airborne oceanographic lidar (AOL).

  11. Investigation of film formation in water-distribution systems by field-emission SEM and spectroscopy techniques

    SciTech Connect

    Liu, J.; Friedman, R.M.; Cortez, E.

    1996-12-31

    EPA has set limits on the concentration of heavy metals in drinking water supplies to protect the public health. Furthermore, the failure of pipes in the water distribution system from corrosion represents a massive investment in rebuilding its infrastructure. We have initiated a program to study the formation of corrosion-inhibition films formed in potable water delivery systems using various chemical phosphate treatments. In particular, blends of ortho- and polyphosphates have recently been used to reduce both lead and copper leaching. Several factors are important to the successful implementation of the phosphate technologies, including film thickness and porosity, rate and stability of formation and water quality conditions. In an attempt to understand the performance of these phosphate blends, advanced analytical techniques have been employed to study the nucleation and growth mechanisms of the passivation films in a variety of water systems. We report here some preliminary results on the study of the film formation by field emission scanning electron microscopy (FESEM) technique.

  12. Minimally invasive field abomasopexy techniques for correction and fixation of left displacement of the abomasum in dairy cows.

    PubMed

    Newman, Kenneth D; Harvey, Denis; Roy, Jean-Philippe

    2008-07-01

    To reduce the potential drawbacks associated with laparotomy techniques for correction and fixation of left displaced abomasums (LDA), minimally invasive techniques have been developed. This chapter reviews the toggle pin suture (TPS) and the laparoscopic abomasopexy procedures used in the field for correction and fixation of the abomasum for correction of left-displacement of the abomasum in dairy cows. The importance of case selection cannot be overestimated. By combining laparoscopy with the principle of the TPS procedure, the lack of visual control associated with the TPS procedure is eliminated, while the advantage of the speed of completion and minimal invasiveness provided by both procedures are maintained. Successful LDA treatment includes not only early detection and treatment of the LDA, but also the prevention of secondary ketosis and aggressive treatment of concurrent disease. PMID:18471576

  13. Boosting family income to promote child development.

    PubMed

    Duncan, Greg J; Magnuson, Katherine; Votruba-Drzal, Elizabeth

    2014-01-01

    Families who live in poverty face disadvantages that can hinder their children's development in many ways, write Greg Duncan, Katherine Magnuson, and Elizabeth Votruba-Drzal. As they struggle to get by economically, and as they cope with substandard housing, unsafe neighborhoods, and inadequate schools, poor families experience more stress in their daily lives than more affluent families do, with a host of psychological and developmental consequences. Poor families also lack the resources to invest in things like high-quality child care and enriched learning experiences that give more affluent children a leg up. Often, poor parents also lack the time that wealthier parents have to invest in their children, because poor parents are more likely to be raising children alone or to work nonstandard hours and have inflexible work schedules. Can increasing poor parents' incomes, independent of any other sort of assistance, help their children succeed in school and in life? The theoretical case is strong, and Duncan, Magnuson, and Votruba-Drzal find solid evidence that the answer is yes--children from poor families that see a boost in income do better in school and complete more years of schooling, for example. But if boosting poor parents' incomes can help their children, a crucial question remains: Does it matter when in a child's life the additional income appears? Developmental neurobiology strongly suggests that increased income should have the greatest effect during children's early years, when their brains and other systems are developing rapidly, though we need more evidence to prove this conclusively. The authors offer examples of how policy makers could incorporate the findings they present to create more effective programs for families living in poverty. And they conclude with a warning: if a boost in income can help poor children, then a drop in income--for example, through cuts to social safety net programs like food stamps--can surely harm them. PMID:25518705

  14. Experimental Research in Boost Driver with EDLCs

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hirokazu

    The supply used in servo systems tends to have a high voltage in order to reduce loss and improve the response of motor drives. We propose a new boost motor driver that comprises EDLCs. The proposed driver has a simple structure, wherein the EDLCs are connected in series to the supply, and comprises a charge circuit to charge the EDLCs. The proposed driver has three advantages over conventional boost drivers. The first advantage is that the driver can easily attain the stable boost voltage. The second advantage is that the driver can reduce input power peaks. In a servo system, the input power peaks become greater than the rated power in order to accelerate the motor rapidly. This implies that the equipments that supply power to servo systems must have sufficient power capacity to satisfy the power peaks. The proposed driver can suppress the increase of the power capacity of supply facilities. The third advantage is that the driver can store almost all of the regenerative energy. Conventional drivers have a braking resistor to suppress the increase in the DC link voltage. This causes a considerable reduction in the efficiency. The proposed driver is more efficient than conventional drivers. In this study, the experimental results confirmed the effectiveness of the proposed driver and showed that the drive performance of the proposed driver is the same as that of a conventional driver. Furthermore, it was confirmed that the results of the simulation of a model of the EDLC module, whose capacitance is dependent on the frequency, correspond well with the experimental results.

  15. Deep diving odontocetes foraging strategies and their prey field as determined by acoustic techniques

    NASA Astrophysics Data System (ADS)

    Giorli, Giacomo

    Deep diving odontocetes, like sperm whales, beaked whales, Risso's dolphins, and pilot whales are known to forage at deep depths in the ocean on squid and fish. These marine mammal species are top predators and for this reason are very important for the ecosystems they live in, since they can affect prey populations and control food web dynamics through top-down effects. The studies presented in this thesis investigate deep diving odontocetes. foraging strategies, and the density and size of their potential prey in the deep ocean using passive and active acoustic techniques. Ecological Acoustic Recorders (EAR) were used to monitor the foraging activity of deep diving odontocetes at three locations around the world: the Josephine Seamount High Sea Marine Protected Area (JHSMPA), the Ligurian Sea, and along the Kona coast of the island of Hawaii. In the JHSMPA, sperm whales. and beaked whales. foraging rates do not differ between night-time and day-time. However, in the Ligurian Sea, sperm whales switch to night-time foraging as the winter approaches, while beaked whales alternate between hunting mainly at night, and both at night and at day. Spatial differences were found in deep diving odontocetes. foraging activity in Hawaii where they forage most in areas with higher chlorophyll concentrations. Pilot whales (and false killer whales, clustered together in the category "blackfishes") and Risso's dolphins forage mainly at night at all locations. These two species adjust their foraging activity with the length of the night. The density and size of animals living in deep sea scattering layers was studied using a DIDSON imaging sonar at multiple stations along the Kona coast of Hawaii. The density of animals was affected by location, depth, month, and the time of day. The size of animals was influenced by station and month. The DIDSON proved to be a successful, non-invasive technique to study density and size of animals in the deep sea. Densities were found to be an

  16. A Composite PWM Control Strategy for Boost Converter

    NASA Astrophysics Data System (ADS)

    Qingfeng, Liu; Zhaoxia, Leng; Jinkun, Sun; Huamin, Wang

    In order to improve the control performance of boost converter with large signal disturbance, a composite PWM control strategy for boost converter operating in continuous condition mode (CCM) was proposed in this paper. The parasitical loss of Boost converter was analyzed and a loss compensation strategy was adopted to design feed-forward tracker for converter. The composite PWM controller consisted of the tracker and PID controller. Simulation and experiment results validated the validity of the control strategy presented in this paper.

  17. Measurement of the intracrystalline self-diffusion of xenon in zeolites by the NMR pulsed field gradient technique

    SciTech Connect

    Heink, W.; Kaerger, J.; Pfeifer, H.; Stallmach, F. )

    1990-03-14

    With use of {sup 129}Xe NMR, the NMR pulsed field gradient technique is applied to study the self-diffusion of xenon adsorbed on zeolites NaX, NaCaA, and ZSM-5. In their dependence on both the type of adsorbent and the sorbate concentration, the self-diffusion coefficients are found to follow the same patterns as previously determined for methane by {sup 1}H NMR. For NaCaA, the comparison of the present results with literature data reveals large discrepancies, while recent computer simulations of xenon self-diffusion in ZSM-5 are found to be in reasonable agreement.

  18. Field test comparison of an autocorrelation technique for determining grain size using a digital 'beachball' camera versus traditional methods

    USGS Publications Warehouse

    Barnard, P.L.; Rubin, D.M.; Harney, J.; Mustain, N.

    2007-01-01

    This extensive field test of an autocorrelation technique for determining grain size from digital images was conducted using a digital bed-sediment camera, or 'beachball' camera. Using 205 sediment samples and >1200 images from a variety of beaches on the west coast of the US, grain size ranging from sand to granules was measured from field samples using both the autocorrelation technique developed by Rubin [Rubin, D.M., 2004. A simple autocorrelation algorithm for determining grain size from digital images of sediment. Journal of Sedimentary Research, 74(1): 160-165.] and traditional methods (i.e. settling tube analysis, sieving, and point counts). To test the accuracy of the digital-image grain size algorithm, we compared results with manual point counts of an extensive image data set in the Santa Barbara littoral cell. Grain sizes calculated using the autocorrelation algorithm were highly correlated with the point counts of the same images (r2 = 0.93; n = 79) and had an error of only 1%. Comparisons of calculated grain sizes and grain sizes measured from grab samples demonstrated that the autocorrelation technique works well on high-energy dissipative beaches with well-sorted sediment such as in the Pacific Northwest (r2 ??? 0.92; n = 115). On less dissipative, more poorly sorted beaches such as Ocean Beach in San Francisco, results were not as good (r2 ??? 0.70; n = 67; within 3% accuracy). Because the algorithm works well compared with point counts of the same image, the poorer correlation with grab samples must be a result of actual spatial and vertical variability of sediment in the field; closer agreement between grain size in the images and grain size of grab samples can be achieved by increasing the sampling volume of the images (taking more images, distributed over a volume comparable to that of a grab sample). In all field tests the autocorrelation method was able to predict the mean and median grain size with ???96% accuracy, which is more than

  19. Application of advanced grid generation techniques for flow field computations about complex configurations

    NASA Technical Reports Server (NTRS)

    Kathong, Monchai; Tiwari, Surendra N.

    1988-01-01

    In the computation of flowfields about complex configurations, it is very difficult to construct a boundary-fitted coordinate system. An alternative approach is to use several grids at once, each of which is generated independently. This procedure is called the multiple grids or zonal grids approach; its applications are investigated. The method conservative providing conservation of fluxes at grid interfaces. The Euler equations are solved numerically on such grids for various configurations. The numerical scheme used is the finite-volume technique with a three-stage Runge-Kutta time integration. The code is vectorized and programmed to run on the CDC VPS-32 computer. Steady state solutions of the Euler equations are presented and discussed. The solutions include: low speed flow over a sphere, high speed flow over a slender body, supersonic flow through a duct, and supersonic internal/external flow interaction for an aircraft configuration at various angles of attack. The results demonstrate that the multiple grids approach along with the conservative interfacing is capable of computing the flows about the complex configurations where the use of a single grid system is not possible.

  20. [THE FORMS OF DELIBERATION INVOLVED IN THE FIELD OF BIOETHICS: TECHNIQUE DELIBERATION AND ETHICS DELIBERATION].

    PubMed

    Neves Pinto, Gerson

    2015-12-01

    In this article the author examines the formulation of the problem of new technologies with their ethical limits and legal. To do this, in a first it is d'assess the contribuitions of the two most important contemporary philosophers who have treated this subject: Jürgen Habermas and Ronald Dworkin, while trying to put them into dialog with the one who has been one of the founders of l'classic ethics: Aristotle. Then, it tries to answer the question of how could we understand this notion that Dworkin nome "moral dislocation" between the random and the choice or well, as the appointed Habermas, "l'extension of the contingency". Finally, we questioned how the Aristotelian distinction between the technical deliberation and deliberative ethical-moral can contribute to a better understanding of the questions on the decisions and choices that will make the moral agents (such as patients or the judges), as well as those relating to the type of deliberation technique chosen by the doctor or by the health professional. PMID:27120826

  1. New experimental technique for detecting the effect of low-frequency electric fields on enzyme structure

    SciTech Connect

    Greco, G. Jr.; Gianfreda, L.; d'Ambrosio, G.; Massa, R.; Scaglione, A.; Scarfi, M.R. )

    1990-01-01

    A new experimental approach has been developed to determine kinetic and thermodynamic parameters of the inactivation of an enzyme under labile conditions both with and without exposure to electrical currents as sources of perturbation. Studies were undertaken to investigate if low-frequency electric currents can accelerate the thermal inactivation of an enzyme through interactions with dipole moments in enzymatic molecules and through related mechanical stresses. The experiments were conducted with the enzyme acid phosphatase. The enzyme was exposed to a 50-Hz current at different densities (10 to 60 mA/cm2 rms) or to a sinusoidal or square-wave current at an average density of 3 mA/cm2 and frequencies from, respectively, 50 Hz to 20 kHz and 500 pulses per second (pps) to 50,000 pps. Positive-control experiments were performed in the presence of a stabilizer or a deactivator. The results indicate that the technique is sensitive to conformational changes that otherwise may be impossible to detect. However, exposure to electric currents under the experimental conditions described herein showed no effects of the currents.

  2. New experimental technique for detecting the effect of low-frequency electric fields on enzyme structure.

    PubMed

    Greco, G; Gianfreda, L; d'Ambrosio, G; Massa, R; Scaglione, A; Scarfi, M R

    1990-01-01

    A new experimental approach has been developed to determine kinetic and thermodynamic parameters of the inactivation of an enzyme under labile conditions both with and without exposure to electrical currents as sources of perturbation. Studies were undertaken to investigate if low-frequency electric currents can accelerate the thermal inactivation of an enzyme through interactions with dipole moments in enzymatic molecules and through related mechanical stresses. The experiments were conducted with the enzyme acid phosphatase. The enzyme was exposed to a 50-Hz current at different densities (10 to 60 mA/cm2 rms) or to a sinusoidal or square-wave current at an average density of 3 mA/cm2 and frequencies from, respectively, 50 Hz to 20 kHz and 500 pulses per second (pps) to 50,000 pps. Positive-control experiments were performed in the presence of a stabilizer or a deactivator. The results indicate that the technique is sensitive to conformational changes that otherwise may be impossible to detect. However, exposure to electric currents under the experimental conditions described herein showed no effects of the currents. PMID:2346508

  3. Earth strain measurements with the transportable laser ranging system: Field techniques and planning

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Dorman, H. J.; Cahill, T.

    1982-01-01

    The potential of the transportable laser ranging system for monitoring the ground deformation around satellite ranging stations and other geodetic control points was examined with emphasis on testing the usefulness of the relative alteration technique. The temporal variation of the ratio of the length of each survey line to the mean length of all survey lines in a given area is directly related to the mean shear strain rate for the area. The data from a series of experimental measurements taken over the Los Angeles basin from a TLRS station at Mt. Wilson show that such ratios can be determined to an accuracy of one part in 10 million with a measurement program lasting for three days and without using any corrections for variations in atmospheric conditions. A numerical experiment using a set of hypothetical data indicates that reasonable estimates of the present shear strain rate and the direction of the principal axes in southern California can be deduced from such measurements over an interval of one to two years.

  4. Combination fracturing/gravel-packing completion technique on the Amberjack, Mississippi Canyon 109 field

    SciTech Connect

    Hannah, R.R.; Park, E.I.; Porter, D.A.; Black, J.W. )

    1994-11-01

    This paper describes a one-step fracturing/gravel-pack (frac-and-pack) completion procedure conducted on the BP Exploration Amberjack platform beginning in early 1992. This platform is 35 miles southwest of Venice, LA. The first four completions on this platform had an average positive skin values of 21. The goal of the frac-and-pack procedure was to reduce these skins to nearly zero. In total, 24 frac-and-pack operations were performed. Details of the fracture design, prefracture testing, fracture design and execution, and production response and a continuing optimization program are discussed. The fractures were performed with the screens in place with the gravel pack after the fracturing operation. The treatments were designed for the tip screenout technique to create wide fractures and to provide proppant loadings exceeding 8 lbm/ft. This paper presents the trend of the declining skin values, along with a discussion of time-dependent skins. The changes in fluids, breakers, and proppants are also presented. The average skin on 14 frac-and-pack completions was 5.3. The average skin on the final eight completions was 0.2.

  5. Validation of a field technique and characterization of fecal glucocorticoid metabolite analysis in wild chimpanzees (Pan troglodytes).

    PubMed

    Murray, Carson M; Heintz, Matthew R; Lonsdorf, Elizabeth V; Parr, Lisa A; Santymire, Rachel M

    2013-01-01

    Monitoring adrenocortical activity in wild primate populations is critical, given the well-documented relationship between stress, health, and reproduction. Although many primate studies have quantified fecal glucocorticoid metabolite (FGM) concentrations, it is imperative that researchers validate their method for each species. Here, we describe and validate a technique for field extraction and storage of FGMs in wild chimpanzees (Pan troglodytes). Our method circumvents many of the logistical challenges associated with field studies while yielding similar results to a commonly used laboratory method. We further validate that our method accurately reflects stress physiology using an adrenocorticotropic hormone challenge in a captive chimpanzee and an FGM peak at parturition in a wild subject. Finally, we quantify circadian patterns for FGMs for the first time in this species. Understanding these patterns may allow researchers to directly link specific events with the stress response. PMID:22968979

  6. Thermal Imagery and Field Techniques to Evaluate Groundwater Nutrient Loading to an Estuary

    NASA Astrophysics Data System (ADS)

    ROSEEN, R. M.; BRANNAKA, L. K.; BALLESTERO, T. P.

    2001-05-01

    Thermal infrared imagery has the potential to be a powerful and affordable tool for coastal managers and scientists to assist in the evaluation of pollution from groundwater. Developments in thermal imagery have improved its accessibility and affordability for use in coastal resource management. An on-going study has applied these new developments in thermal imagery to evaluate groundwater discharge on a large scale. In April and August of 2000 a series of thermal infrared aerial surveys were flown over the Great Bay Estuary in coastal New Hampshire. This study delineated the large-scale groundwater flux to an estuary. This flux was then used to estimate the nutrient loading to the estuarine ecosystem. The aerial survey covered the Great Bay, including nearly 50 miles of shoreline and four of the major contributing rivers. The August survey was completed in the equivalent of an afternoon. The images were available immediately with no post-processing required, and are being mosaicked into larger contiguous images to be incorporated into GIS applications. The images were studied for thermal anomalies as an indication of upwelling groundwater. The surface areas of each individual groundwater discharge zones were computed by GIS analysis of the photo-identified discharge zones. This was accomplished by use of gray-scale images calibrated to a known temperature range. The suspected groundwater discharge zones were identified in the field, characterized for hydrologic parameters, and sampled for water quality. Preliminary results suggest that groundwater is a significant component of the freshwater influx to the Great Bay, contributing half as much as the 10-year daily average of the Lamprey River. The Lamprey River is the largest (183 sq. mi. drainage area) of the four major surface freshwater sources to the upper Great Bay. Of particular significance, the estimated groundwater contribution was as much as 150%\\ that contributed by the Lamprey River during the summer

  7. GRAIL gravity field recovery based on the short-arc integral equation technique: Simulation studies and first real data results

    NASA Astrophysics Data System (ADS)

    Klinger, B.; Baur, O.; Mayer-Gürr, T.

    2014-02-01

    The NASA mission GRAIL (Gravity Recovery And Interior Laboratory) makes use of low-low satellite-to-satellite tracking between the spacecraft GRAIL-A (Ebb) and GRAIL-B (Flow) to determine high-resolution lunar gravity field features. The inter-satellite measurements are independent of the visibility of the spacecraft from Earth, and hence provide data for both the nearside and the farside of the Moon. We propose to exploit this ranging data by an integral equation approach using short orbital arcs; it is based on the reformulation of Newton's equation of motion as a boundary value problem. This technique has been successfully applied for the recovery of the gravity field of the Earth from the Gravity Recovery And Climate Experiment (GRACE) project-the terrestrial sibling of GRAIL. By means of a series of simulation studies we demonstrate the potential of the approach. We pay particular attention on a priori gravity field information, orbital arc length, observation noise and the impact of spectral aliasing (omission error). Finally, we compute a first lunar gravity model (GrazLGM200a) from real data of the primary mission phase (March 1, 2012 to May 29, 2012). The unconstrained model is expanded up to spherical harmonic degree and order 200. From our simulations and real data results we conclude that the integral equation approach is well suited for GRAIL gravity field recovery.

  8. SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

    DOEpatents

    Jesse, Stephen [Knoxville, TN; Geohegan, David B [Knoxville, TN; Guillorn, Michael [Brooktondale, NY

    2009-02-17

    Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

  9. Development of Field-Reversed Configuration Plasma Gun Formation Techniques for Magnetized Target Fusion

    NASA Astrophysics Data System (ADS)

    Lynn, Alan; Gilmore, Mark; Wynkoop, Tyler; Intrator, Thomas; Weber, Thomas

    2012-10-01

    Magnetized Target Fusion (MTF) is an innovative approach for a relatively fast and cheap path to the production of fusion energy that utilizes magnetic confinement to assist in the compression of a hot plasma to thermonuclear conditions by an external driver. Los Alamos National Laboratory (LANL) is currently pursing demonstration of the MTF concept via compression of an FRC (field-reversed configuration) plasma by a metal liner z-pinch in conjunction with the Air Force Research Laboratory in Albuquerque, NM. A key physics issue for the FRC as an MTF target lies in the initial pre-ionization (PI) stage. The PI formation process determines the amount of magnetic flux that can be trapped to form the FRC. This trapped flux plays an important role in the FRC's final equilibrium, transport, and stability properties. It also provides the route to greatest potential gains in FRC lifetime, which is essential to provide enough time to translate and compress the FRC effectively. In conjunction with LANL we plan to test and characterize a new system to improve the initial PI plasma formation. This system will use an array of plasma guns to form the initial plasma. Initial characterization of the plasma gun behavior will be presented.

  10. Design and real time implementation of single phase boost power factor correction converter.

    PubMed

    Bouafassa, Amar; Rahmani, Lazhar; Mekhilef, Saad

    2015-03-01

    This paper presents a real time implementation of the single-phase power factor correction (PFC) AC-DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations. PMID:25457043

  11. Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water

    USGS Publications Warehouse

    Rosenberry, Donald O.; LaBaugh, James W.

    2008-01-01

    This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological

  12. New variables, the gravitational action and boosted quasilocal stress - energy - momentum

    NASA Astrophysics Data System (ADS)

    Lau, Stephen R.

    1996-06-01

    This paper presents a complete set of quasilocal densities which describe the stress - energy - momentum content of the gravitational field and which are built with Ashtekar variables. The densities are defined on a 2-surface B which bounds a generic spacelike hypersurface 0264-9381/13/6/019/img1 of spacetime. The method used to derive the set of quasilocal densities is a Hamilton - Jacobi analysis of a suitable covariant action principle for the Ashtekar variables. As such, the theory presented here is an Ashtekar-variable reformulation of the metric theory of quasilocal stress - energy - momentum originally due to Brown and York. This work also investigates how the quasilocal densities behave under generalized boosts, i.e. switches of the 0264-9381/13/6/019/img1 slice spanning B. It is shown that under such boosts the densities behave in a manner which is similar to the simple boost law for energy - momentum 4-vectors in special relativity. The developed formalism is used to obtain a collection of 2-surface or boost invariants. With these invariants, one may `build' several different mass definitions in general relativity, such as the Hawking expression. Also discussed in detail in this paper is the canonical action principle as applied to bounded spacetime regions with `sharp corners'.

  13. Remote sensing techniques to monitor nitrogen-driven carbon dynamics in field corn

    NASA Astrophysics Data System (ADS)

    Corp, Lawrence A.; Middleton, Elizabeth M.; Campbell, Petya K. E.; Huemmrich, K. Fred; Cheng, Yen-Ben; Daughtry, Craig S. T.

    2009-08-01

    Patterns of change in vegetation growth and condition are one of the primary indicators of the present and future ecological status of the globe. Nitrogen (N) is involved in photochemical processes and is one of the primary resources regulating plant growth. As a result, biological carbon (C) sequestration is driven by N availability. Large scale monitoring of photosynthetic processes are currently possible only with remote sensing systems that rely heavily on passive reflectance (R) information. Unlike R, fluorescence (F) emitted from chlorophyll is directly related to photochemical reactions and has been extensively used for the elucidation of the photosynthetic pathways. Recent advances in passive fluorescence instrumentation have made the remote acquisition of solar-induced fluorescence possible. The goal of this effort is to evaluate existing reflectance and emerging fluorescence methodologies for determining vegetation parameters related to photosynthetic function and carbon sequestration dynamics in plants. Field corn N treatment levels of 280, 140, 70, and 0 kg N / ha were sampled from an intensive test site for a multi-disciplinary project, Optimizing Production Inputs for Economic and Environmental Enhancement (OPE). Aircraft, near-ground, and leaf-level measurements were used to compare and contrast treatment effects within this experiment site assessed with both reflectance and fluorescence approaches. A number of spectral indices including the R derivative index D730/D705, the normalized difference of R750 vs. R705, and simple ratio R800/R750 differentiated three of the four N fertilization rates and yielded high correlations to three important carbon parameters: C:N, light use efficiency, and grain yield. These results advocate the application of hyperspectral sensors for remotely monitoring carbon cycle dynamics in terrestrial ecosystems.

  14. A Field Evaluation of Airborne Techniques for Detection of Unexploded Ordnance

    SciTech Connect

    Bell, D.; Doll, W.E.; Hamlett, P.; Holladay, J.S.; Nyquist, J.E.; Smyre, J.; Gamey, T.J.

    1999-03-14

    US Defense Department estimates indicate that as many as 11 million acres of government land in the U. S. may contain unexploded ordnance (UXO), with the cost of identifying and disposing of this material estimated at nearly $500 billion. The size and character of the ordnance, types of interference, vegetation, geology, and topography vary from site to site. Because of size or composition, some ordnance is difficult to detect with any geophysical method, even under favorable soil and cultural interference conditions. For some sites, airborne methods may provide the most time and cost effective means for detection of UXO. Airborne methods offer lower risk to field crews from proximity to unstable ordnance, and less disturbance of sites that maybe environmentally sensitive. Data were acquired over a test site at Edwards AFB, CA using airborne magnetic, electromagnetic, multispectral and thermal sensors. Survey areas included sites where trenches might occur, and a test site in which we placed deactivated ordnance, ranging in size from small ''bomblets'' to large bombs. Magnetic data were then acquired with the Aerodat HM-3 system, which consists of three cesium magnetometers within booms extending to the front and sides of the helicopter, and mounted such that the helicopter can be flown within 3m of the surface. Electromagnetic data were acquired with an Aerodat 5 frequency coplanar induction system deployed as a sling load from a helicopter, with a sensor altitude of 15m. Surface data, acquired at selected sites, provide a comparison with airborne data. Multispectral and thermal data were acquired with a Daedelus AADS 1268 system. Preliminary analysis of the test data demonstrate the value of airborne systems for UXO detection and provide insight into improvements that might make the systems even more effective.

  15. Boosted di-boson from a mixed heavy stop

    SciTech Connect

    Ghosh, Diptimoy

    2013-12-01

    The lighter mass eigenstate ($\\widetilde{t}_1$) of the two top squarks, the scalar superpartners of the top quark, is extremely difficult to discover if it is almost degenerate with the lightest neutralino ($\\widetilde{\\chi}_1^0$), the lightest and stable supersymmetric particle in the R-parity conserving supersymmetry. The current experimental bound on $\\widetilde{t}_1$ mass in this scenario stands only around 200 GeV. For such a light $\\widetilde{t}_1$, the heavier top squark ($\\widetilde{t}_2$) can also be around the TeV scale. Moreover, the high value of the higgs ($h$) mass prefers the left and right handed top squarks to be highly mixed allowing the possibility of a considerable branching ratio for $\\widetilde{t}_2 \\to \\widetilde{t}_1 h$ and $\\widetilde{t}_2 \\to \\widetilde{t}_1 Z$. In this paper, we explore the above possibility together with the pair production of $\\widetilde{t}_2$ $\\widetilde{t}_2^*$ giving rise to the spectacular di-boson + missing transverse energy final state. For an approximately 1 TeV $\\widetilde{t}_2$ and a few hundred GeV $\\widetilde{t}_1$ the final state particles can be moderately boosted which encourages us to propose a novel search strategy employing the jet substructure technique to tag the boosted $h$ and $Z$. The reconstruction of the $h$ and $Z$ momenta also allows us to construct the stransverse mass $M_{T2}$ providing an additional efficient handle to fight the backgrounds. We show that a 4--5$\\sigma$ signal can be observed at the 14 TeV LHC for $\\sim$ 1 TeV $\\widetilde{t}_2$ with 100 fb$^{-1}$ integrated luminosity.

  16. Monitoring and Modeling the Impact of Grazers Using Visual, Remote and Traditional Field Techniques

    NASA Astrophysics Data System (ADS)

    Roadknight, C. M.; Marshall, I. W.; Rose, R. J.

    2009-04-01

    The relationship between wild and domestic animals and the landscape they graze upon is important to soil erosion studies because they are a strong influence on vegetation cover (a key control on the rate of overland flow runoff), and also because the grazers contribute directly to sediment transport via carriage and indirectly by exposing fresh soil by trampling and burrowing/excavating. Quantifying the impacts of these effects on soil erosion and their dependence on grazing intensity, in complex semi-natural habitats has proved difficult. This is due to lack of manpower to collect sufficient data and weak standardization of data collection between observers. The advent of cheaper and more sophisticated digital camera technology and GPS tracking devices has lead to an increase in the amount of habitat monitoring information that is being collected. We report on the use of automated trail cameras to continuously capture images of grazer (sheep, rabbits, deer) activity in a variety of habitats at the Moor House nature reserve in northern England. As well as grazer activity these cameras also give valuable information on key climatic soil erosion factors such as snow, rain and wind and plant growth and thus allow the importance of a range of grazer activities and the grazing intensity to be estimated. GPS collars and more well established survey methods (erosion monitoring, dung counting and vegetation surveys) are being used to generate a detailed representation of land usage and plan camera siting. This paper describes the data collection techniques, outlines the quantitative and qualitative data collected and proposes online and offline systems that can reduce the data processing time and increase focus on important subsets in the collected data. We also present a land usage model that estimates grazing intensity, grazer behaviours and their impact on soil coverage at sites where cameras have not been deployed, based on generalising from camera sites to other

  17. Linearized stability analysis and design of a flyback dc-dc boost regulator.

    NASA Technical Reports Server (NTRS)

    Wester, G. W.

    1973-01-01

    Analytic expressions for the small-signal power-stage describing functions of a switched dc-dc boost regulator are derived from an approximate continuous circuit model which is developed by a time-averaging technique. Closed-loop stability is attained through the design of frequency compensation of the loop gain. Open- and closed-loop regulator output impedances are derived from the linearized models for the given configuration. The analysis and design are compared with and confirmed by breadboard measurements.

  18. Centaur boost pump turbine icing investigation

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. J.

    1976-01-01

    An investigation was conducted to determine if ice formation in the Centaur vehicle liquid oxygen boost pump turbine could prevent rotation of the pump and whether or not this phenomenon could have been the failure mechanism for the Titan/Centaur vehicle TC-1. The investigation consisted of a series of tests done in the LeRC Space Power Chamber Facility to evaluate evaporative cooling behavior patterns in a turbine as a function of the quantity of water trapped in the turbine and as a function of the vehicle ascent pressure profile. It was found that evaporative freezing of water in the turbine housing, due to rapid depressurization within the turbine during vehicle ascent, could result in the formation of ice that would block the turbine and prevent rotation of the boost pump. But for such icing conditions to exist it would be necessary to have significant quantities of water in the turbine and/or its components, and the turbine housing temperature would have to be colder than 40 F at vehicle liftoff.

  19. Low temperature operation of a boost converter

    SciTech Connect

    Moss, B.S.; Boudreaux, R.R.; Nelms, R.M.

    1996-12-31

    The development of satellite power systems capable of operating at low temperatures on the order of 77K would reduce the heating system required on deep space vehicles. The power supplies in the satellite power system must be capable of operating at these temperatures. This paper presents the results of a study into the operation of a boost converter at temperatures close to 77K. The boost converter is designed to supply an output voltage and power of 42 V and 50 W from a 28 V input source. The entire system, except the 28 V source, is placed in the environmental chamber. This is important because the system does not require any manual adjustments to maintain a constant output voltage with a high efficiency. The constant 42 V output of this converter is a benefit of the application of a CMOS microcontroller in the feedback path. The switch duty cycle is adjusted by the microcontroller to maintain a constant output voltage. The efficiency of the system varied less than 1% over the temperature range of 22 C to {minus}184 C and was approximately 94.2% when the temperature was {minus}184 C.

  20. Domain adaptive boosting method and its applications

    NASA Astrophysics Data System (ADS)

    Geng, Jie; Miao, Zhenjiang

    2015-03-01

    Differences of data distributions widely exist among datasets, i.e., domains. For many pattern recognition, nature language processing, and content-based analysis systems, a decrease in performance caused by the domain differences between the training and testing datasets is still a notable problem. We propose a domain adaptation method called domain adaptive boosting (DAB). It is based on the AdaBoost approach with extensions to cover the domain differences between the source and target domains. Two main stages are contained in this approach: source-domain clustering and source-domain sample selection. By iteratively adding the selected training samples from the source domain, the discrimination model is able to achieve better domain adaptation performance based on a small validation set. The DAB algorithm is suitable for the domains with large scale samples and easy to extend for multisource adaptation. We implement this method on three computer vision systems: the skin detection model in single images, the video concept detection model, and the object classification model. In the experiments, we compare the performances of several commonly used methods and the proposed DAB. Under most situations, the DAB is superior.

  1. Velocity field measurement in gas-liquid metal two-phase flow with use of PIV and neutron radiography techniques.

    PubMed

    Saito, Y; Mishima, K; Tobita, Y; Suzuki, T; Matsubayashi, M

    2004-10-01

    To establish reasonable safety concepts for the realization of commercial liquid-metal fast breeder reactors, it is indispensable to demonstrate that the release of excessive energy due to re-criticality of molten core could be prevented even if a severe core damage accident took place. Two-phase flow due to the boiling of fuel-steel mixture in the molten core pool has a larger liquid-to-gas density ratio and higher surface tension in comparison with those of ordinary two-phase flows such as air-water flow. In this study, to investigate the effect of the recirculation flow on the bubble behavior, visualization and measurement of nitrogen gas-molten lead bismuth in a rectangular tank was performed by using neutron radiography and particle image velocimetry techniques. Measured flow parameters include flow regime, two-dimensional void distribution, and liquid velocity field in the tank. The present technique is applicable to the measurement of velocity fields and void fraction, and the basic characteristics of gas-liquid metal two-phase mixture were clarified. PMID:15246418

  2. [Introducing marketing strategies and techniques into the field of voluntary blood donation, to meet the rise in blood demand].

    PubMed

    Pesavento, S; Bégué, L

    2011-04-01

    Social marketing uses marketing principles and techniques to induce a target audience to voluntary accept, reject, change or abandon a behaviour for the benefit of individuals, groups, or society as a whole. Thus, individual or societal gain is the primary goal of social marketing. This kind of marketing is frequently used in the United States or in Canada in several fields such as healthcare, social work, or the environment. In 2008, we introduced these strategies and techniques in the field of blood donation in France. This article describes what has been achieved in the last three years and outlines the main steps in the social marketing planning process: analyzing the social marketing environment, defining target audiences and objectives, building and implementing strategies and action plans, evaluating and monitoring. On the way to self-sufficiency, while respecting donors, social marketing is additional to the work done by the blood collection staffs, communication teams, and volunteers. Social marketing is a complementary tool to the work done by the blood collection staff, communication teams and blood donation organizations and can help to meet the challenge of self-sufficiency while still allowing for the privacy and rights of donors. PMID:21474359

  3. A simple measuring technique of surface flow velocity to analyze the behavior of velocity fields in hydraulic engineering applications.

    NASA Astrophysics Data System (ADS)

    Tellez, Jackson; Gomez, Manuel; Russo, Beniamino; Redondo, Jose M.

    2015-04-01

    An important achievement in hydraulic engineering is the proposal and development of new techniques for the measurement of field velocities in hydraulic problems. The technological advances in digital cameras with high resolution and high speed found in the market, and the advances in digital image processing techniques now provides a tremendous potential to measure and study the behavior of the water surface flows. This technique was applied at the Laboratory of Hydraulics at the Technical University of Catalonia - Barcelona Tech to study the 2D velocity fields in the vicinity of a grate inlet. We used a platform to test grate inlets capacity with dimensions of 5.5 m long and 4 m wide allowing a zone of useful study of 5.5m x 3m, where the width is similar of the urban road lane. The platform allows you to modify the longitudinal slopes from 0% to 10% and transversal slope from 0% to 4%. Flow rates can arrive to 200 l/s. In addition a high resolution camera with 1280 x 1024 pixels resolution with maximum speed of 488 frames per second was used. A novel technique using particle image velocimetry to measure surface flow velocities has been developed and validated with the experimental data from the grate inlets capacity. In this case, the proposed methodology can become a useful tools to understand the velocity fields of the flow approaching the inlet where the traditional measuring equipment have serious problems and limitations. References DigiFlow User Guide. (2012), (June). Russo, B., Gómez, M., & Tellez, J. (2013). Methodology to Estimate the Hydraulic Efficiency of Nontested Continuous Transverse Grates. Journal of Irrigation and Drainage Engineering, 139(10), 864-871. doi:10.1061/(ASCE)IR.1943-4774.0000625 Teresa Vila (1), Jackson Tellez (1), Jesus Maria Sanchez (2), Laura Sotillos (1), Margarita Diez (3, 1), and J., & (1), M. R. (2014). Diffusion in fractal wakes and convective thermoelectric flows. Geophysical Research Abstracts - EGU General Assembly 2014

  4. International summer course in geobiology gives emerging field a boost

    NASA Astrophysics Data System (ADS)

    Berelson, William

    Educators are always concerned with the quality of graduate courses and the fate of their graduate students. When my father wrote Graduate Education in the United States [Berelson, 1960], graduate students learned from lectures, lab, and technical assignments; they learned from one-on-one tutoring, from their fellow students, and they learned by taking on challenging research topics and producing and presenting justifiable results. That educational style hasn't changed. But in the 1950s and 1960s, there was no interdisciplinary graduate course taught on Catalina Island in which students and instructors mingled during kayak trips, mountain hikes, and during breakfast, lunch, and dinner.

  5. Field Observations of Bioaerosols: What We've Learned from Fluorescence, Genetic, and Microscopic Techniques (Invited)

    NASA Astrophysics Data System (ADS)

    Huffman, J. A.; Fröhlich-Nowoisky, J.; Després, V. R.; Elbert, W.; Sinha, B.; Andreae, M. O.; Pöschl, U.

    2009-12-01

    Biogenic aerosols are ubiquitous in the Earth’s atmosphere, influencing atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms, and they can cause or enhance human, animal, and plant diseases. Moreover, they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei (CCN, IN). Primary biogenic aerosol particles (PBAP) such as pollen, fungal spores, and bacteria are emitted directly from the biosphere to the atmosphere. Microscopic investigations have shown that PBAP account for up to ~30% of fine and up to ~70% of coarse particulate matter in rural and rain forest air, and the estimates of PBA emissions range from ~60 Tg a-1 of fine particles up to ~1000 Tg a-1 of total particulate matter. Fungal spores account for a large proportion of PBA with typical number and mass concentrations of ~104 m-3 and ~1 μg m-3 in continental boundary layer air and estimated global emissions of the order of ~50 Tg a-1 and 200 m-2 s-1, respectively [1]. The actual abundance, variability and diversity of PBAP are still poorly understood and quantified, however. By measuring fluorescence at excitation and emission wavelengths specific to viable cells, online techniques with time resolution of minutes are able to detect fluorescent biological aerosol particles (FBAP), which represent a lower limit for the actual abundance of coarse (> 1 μm) PBAP [2]. Continuous sampling (1 - 4 months) was performed at various locations including pristine rain forest, rural and polluted urban sites. Each study exhibited a similar average particle number distribution dominated by a peak at ~3 μm, with coarse FBAP concentrations of the order of ~5x104 m-3 and ~1 μg m-3. Recent advances in the DNA analysis and molecular genetic characterization of aerosol filter samples yield new information about the sources and composition of PBA and provide new insight into regional and global

  6. Correction of breathing-induced errors in magnetic resonance thermometry of hyperthermia using multiecho field fitting techniques

    PubMed Central

    Wyatt, Cory R.; Soher, Brian J.; MacFall, James R.

    2010-01-01

    : In this paper, we have developed an extension of the referenceless method to correct for breathing errors using multiecho fitting methods to fit for the B0 field in the fatty tissue and using measured field changes as references to extrapolate field corrections into a water-only (tumor) region. This technique has been validated in a number of situations, and in all cases, the correction method has been shown to greatly reduce temperature error in water-rich regions. The method has also been shown to be an improvement over similar methods that use image phase changes instead of field changes, particularly when temperature changes are induced. PMID:21302786

  7. Supine Craniospinal Irradiation Using a Proton Pencil Beam Scanning Technique Without Match Line Changes for Field Junctions

    SciTech Connect

    Lin, Haibo Ding, Xuanfeng; Kirk, Maura; Liu, Haoyang; Zhai, Huifang; Hill-Kayser, Christine E.; Lustig, Robert A.; Tochner, Zelig; Both, Stefan; McDonough, James

    2014-09-01

    Purpose: To propose and validate a craniospinal irradiation approach using a proton pencil beam scanning technique that overcomes the complexity of the planning associated with feathering match lines. Methods and Materials: Ten craniospinal irradiation patients had treatment planned with gradient dose optimization using the proton pencil beam scanning technique. The robustness of the plans was evaluated by shifting the isocenter of each treatment field by ±3 mm in the longitudinal direction and was compared with the original nonshifted plan with metrics of conformity number, homogeneity index, and maximal cord doses. An anthropomorphic phantom study using film measurements was carried out on a plan with 5-cm junction length. To mimic setup errors in the phantom study, fields were recalculated with isocenter shifts of 1, 3, 5, and 10 mm longitudinally, and compared with the original plans and measurements. Results: Uniform dose coverage to the entire target volumes was achieved using the gradient optimization approach with averaged junction lengths of 6.7 ± 0.5 cm. The average conformity number and homogeneity index equaled 0.78 ± 0.03 and 1.09 ± 0.01, respectively. Setup errors of 3 mm per field (6 mm in worst-case scenario) caused on average 4.6% lower conformity number 2.5% higher homogeneity index and maximal cord dose of 4216.1 ± 98.2 cGy. When the junction length was 5 cm or longer, setup errors of 6 mm resulted in up to 12% dosimetric deviation. Consistent results were reached between film measurements and planned dose profiles in the junction area. Conclusions: Longitudinal setup errors directly reduce the dosimetric accuracy of the proton craniospinal irradiation treatment with matched proton pencil beam scanning fields. The reported technique creates a slow dose gradient in the junction area, which makes the treatment more robust to longitudinal setup errors compared to conventional feathering methods.

  8. Frequency-offset separated oscillatory fields: A demonstration of a new technique for a measurement of the helium n=2 triplet P fine structure

    NASA Astrophysics Data System (ADS)

    Fitzakerley, D. W.; Kato, K.; George, M. C.; Vutha, A. C.; Skinner, T. D. G.; Bezginov, N.; Hessels, E. A.

    2016-05-01

    We perform a proof-of-principle demonstration of the frequency-offset separated oscillatory field (FOSOF) technique. For the FOSOF technique, the two separated field have frequencies which are offset from each other, so that the relative phases of the fields varies linearly in time. This proof-of-principle demonstration measures the 23 P1 m = 1 to 23 P2 m = 1 transition in atomic helium and demonstrates the usefulness of the FOSOF technique for high-precision atomic measurements. Supported by NSERC, CRC.

  9. Successful field evaluation of the efficiency of a gas gravity drainage process by applying recent developments in Sponge coring technique in a major oil field

    SciTech Connect

    Durandeau, M.; El-Emam, M.; Anis, A.H.; Fanti, G.

    1995-11-01

    This paper describes the application and integration of new technologies and recent developments in Sponge coring and presents the methodology used to carry out successfully the various phases of well designed Sponge coring project, including the coring phase, the on-site measurements and the full evaluation of the Sponge core samples. A field case is presented where a Sponge coring project was accomplished to obtain accurate fluids distribution and evaluate the gas gravity drainage efficiency in one of the Arab D sub-reservoirs of a major oil field offshore Abu Dhabi. A Sponge coring technology team was created to optimize the methodology used during Sponge coring an minimize the uncertainties which persisted on some of the previous operations. The effectiveness of the technique is discussed, with comparison to open hole logs and SCAL data. Realistic petrophysical parameters were obtained from non-invaded, native-state core samples. The effective oil saturation obtained from the Sponge core analysis results showed that the gravity segregation mechanism has been very active and efficient to recover the oil in the reservoir.

  10. Estimation of VOC emissions from produced-water treatment ponds in Uintah Basin oil and gas field using modeling techniques

    NASA Astrophysics Data System (ADS)

    Tran, H.; Mansfield, M. L.; Lyman, S. N.; O'Neil, T.; Jones, C. P.

    2015-12-01

    Emissions from produced-water treatment ponds are poorly characterized sources in oil and gas emission inventories that play a critical role in studying elevated winter ozone events in the Uintah Basin, Utah, U.S. Information gaps include un-quantified amounts and compositions of gases emitted from these facilities. The emitted gases are often known as volatile organic compounds (VOCs) which, beside nitrogen oxides (NOX), are major precursors for ozone formation in the near-surface layer. Field measurement campaigns using the flux-chamber technique have been performed to measure VOC emissions from a limited number of produced water ponds in the Uintah Basin of eastern Utah. Although the flux chamber provides accurate measurements at the point of sampling, it covers just a limited area of the ponds and is prone to altering environmental conditions (e.g., temperature, pressure). This fact raises the need to validate flux chamber measurements. In this study, we apply an inverse-dispersion modeling technique with evacuated canister sampling to validate the flux-chamber measurements. This modeling technique applies an initial and arbitrary emission rate to estimate pollutant concentrations at pre-defined receptors, and adjusts the emission rate until the estimated pollutant concentrations approximates measured concentrations at the receptors. The derived emission rates are then compared with flux-chamber measurements and differences are analyzed. Additionally, we investigate the applicability of the WATER9 wastewater emission model for the estimation of VOC emissions from produced-water ponds in the Uintah Basin. WATER9 estimates the emission of each gas based on properties of the gas, its concentration in the waste water, and the characteristics of the influent and treatment units. Results of VOC emission estimations using inverse-dispersion and WATER9 modeling techniques will be reported.

  11. High-Dose Split-Course Radiation Therapy for Anal Cancer: Outcome Analysis Regarding the Boost Strategy (CORS-03 Study)

    SciTech Connect

    Hannoun-Levi, Jean-Michel; Ortholan, Cecile; Resbeut, Michel; Teissier, Eric; Ronchin, Philippe; Cowen, Didier; Zaccariotto, Audrey; Benezery, Karen; Francois, Eric; Salem, Naji; Ellis, Steve; Azria, David; Gerard, Jean-Pierre

    2011-07-01

    Purpose: To retrospectively assess the clinical outcome in anal cancer patients treated with split-course radiation therapy and boosted through external-beam radiation therapy (EBRT) or brachytherapy (BCT). Methods and Materials: From January 2000 to December 2004, a selected group (162 patients) with invasive nonmetastatic anal squamous cell carcinoma was studied. Tumor staging reported was T1 = 31 patients (19%), T2 = 77 patients (48%), T3 = 42 patients (26%), and T4= 12 patients (7%). Lymph node status was N0-1 (86%) and N2-3 (14%). Patients underwent a first course of EBRT: mean dose 45.1 Gy (range, 39.5-50) followed by a boost: mean dose 17.9 Gy (range, 8-25) using EBRT (76 patients, 47%) or BCT (86 patients, 53%). All characteristics of patients and tumors were well balanced between the BCT and EBRT groups. Results: The mean overall treatment time (OTT) was 82 days (range, 45-143) and 67 days (range, 37-128) for the EBRT and BCT groups, respectively (p < 0.001). The median follow-up was 62 months (range, 2-108). The 5-year cumulative rate of local recurrence (CRLR) was 21%. In the univariate analysis, the prognostic factors for CRLR were as follows: T stage (T1-2 = 15% vs. T3-4 = 36%, p = 0.03), boost technique (BCT = 12% vs. EBRT = 33%, p = 0.002) and OTT (OTT <80 days = 14%, OTT {>=}80 days = 34%, p = 0.005). In the multivariate analysis, BCT boost was the unique prognostic factor (hazard ratio = 0.62 (0.41-0.92). In the subgroup of patients with OTT <80 days, the 5-year CRLR was significantly increased with the BCT boost (BC = 9% vs. EBRT = 28%, p = 0.03). In the case of OTT {>=}80 days, the 5-year CRLR was not affected by the boost technique (BCT = 29% vs. EBRT = 38%, p = 0.21). Conclusion: In anal cancer, when OTT is <80 days, BCT boost is superior to EBRT boost for CRLR. These results suggest investigating the benefit of BCT boost in prospective trials.

  12. REBoost: probabilistic resampling for boosted pedestrian detection

    NASA Astrophysics Data System (ADS)

    Lai, Shiming; Liu, Yu; Zhang, Maojun; Theobald, Barry-John

    2011-12-01

    Cascaded object detectors have demonstrated great success in fast object detection, where image regions can quickly be rejected using a cascade of increasingly complex rejectors/detectors. Although such cascaded detectors typically are fast and require minimal computation, they usually require iterative training, where classifiers are retrained to optimize rejection thresholds after testing on a validation set. We propose a cascaded object detector that uses probabilistic resampling for boosting reweighting, which has the advantage that only a single training step is required. Decision thresholds can be tuned on a validation set without the need for classifier retraining. Empirical results on a pedestrian detection task demonstrate that this reweighting results in a strong classifier that quickly rejects image regions and offers higher accuracy than other competing approaches.

  13. Boosted X Waves in Nonlinear Optical Systems

    SciTech Connect

    Arevalo, Edward

    2010-01-15

    X waves are spatiotemporal optical waves with intriguing superluminal and subluminal characteristics. Here we theoretically show that for a given initial carrier frequency of the system localized waves with genuine superluminal or subluminal group velocity can emerge from initial X waves in nonlinear optical systems with normal group velocity dispersion. Moreover, we show that this temporal behavior depends on the wave detuning from the carrier frequency of the system and not on the particular X-wave biconical form. A spatial counterpart of this behavior is also found when initial X waves are boosted in the plane transverse to the direction of propagation, so a fully spatiotemporal motion of localized waves can be observed.

  14. Boosting jet power in black hole spacetimes

    PubMed Central

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W.; Liebling, Steven L.; Motl, Patrick M.; Garrett, Travis

    2011-01-01

    The extraction of rotational energy from a spinning black hole via the Blandford–Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux. PMID:21768341

  15. Boosting jet power in black hole spacetimes

    NASA Astrophysics Data System (ADS)

    Neilsen, D.; Lehner, L.; Palenzuela, C.; Hirschmann, E. W.; Liebling, S. L.; Motl, P. M.; Garrett, T.

    2011-08-01

    The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

  16. Lessons in modern digital field geology: Open source software, 3D techniques, and the new world of digital mapping

    NASA Astrophysics Data System (ADS)

    Pavlis, Terry; Hurtado, Jose; Langford, Richard; Serpa, Laura

    2014-05-01

    Although many geologists refuse to admit it, it is time to put paper-based geologic mapping into the historical archives and move to the full potential of digital mapping techniques. For our group, flat map digital geologic mapping is now a routine operation in both research and instruction. Several software options are available, and basic proficiency with the software can be learned in a few hours of instruction and practice. The first practical field GIS software, ArcPad, remains a viable, stable option on Windows-based systems. However, the vendor seems to be moving away from ArcPad in favor of mobile software solutions that are difficult to implement without GIS specialists. Thus, we have pursued a second software option based on the open source program QGIS. Our QGIS system uses the same shapefile-centric data structure as our ArcPad system, including similar pop-up data entry forms and generic graphics for easy data management in the field. The advantage of QGIS is that the same software runs on virtually all common platforms except iOS, although the Android version remains unstable as of this writing. A third software option we are experimenting with for flat map-based field work is Fieldmove, a derivative of the 3D-capable program Move developed by Midland Valley. Our initial experiments with Fieldmove are positive, particularly with the new, inexpensive (<300Euros) Windows tablets. However, the lack of flexibility in data structure makes for cumbersome workflows when trying to interface our existing shapefile-centric data structures to Move. Nonetheless, in spring 2014 we will experiment with full-3D immersion in the field using the full Move software package in combination with ground based LiDAR and photogrammetry. One new workflow suggested by our initial experiments is that field geologists should consider using photogrammetry software to capture 3D visualizations of key outcrops. This process is now straightforward in several software packages, and

  17. Glucose Starvation Boosts Entamoeba histolytica Virulence

    PubMed Central

    Tovy, Ayala; Hertz, Rivka; Siman-Tov, Rama; Syan, Sylvie; Faust, Daniela; Guillen, Nancy; Ankri, Serge

    2011-01-01

    The unicellular parasite, Entamoeba histolytica, is exposed to numerous adverse conditions, such as nutrient deprivation, during its life cycle stages in the human host. In the present study, we examined whether the parasite virulence could be influenced by glucose starvation (GS). The migratory behaviour of the parasite and its capability to kill mammalian cells and to lyse erythrocytes is strongly enhanced following GS. In order to gain insights into the mechanism underlying the GS boosting effects on virulence, we analyzed differences in protein expression levels in control and glucose-starved trophozoites, by quantitative proteomic analysis. We observed that upstream regulatory element 3-binding protein (URE3-BP), a transcription factor that modulates E.histolytica virulence, and the lysine-rich protein 1 (KRiP1) which is induced during liver abscess development, are upregulated by GS. We also analyzed E. histolytica membrane fractions and noticed that the Gal/GalNAc lectin light subunit LgL1 is up-regulated by GS. Surprisingly, amoebapore A (Ap-A) and cysteine proteinase A5 (CP-A5), two important E. histolytica virulence factors, were strongly down-regulated by GS. While the boosting effect of GS on E. histolytica virulence was conserved in strains silenced for Ap-A and CP-A5, it was lost in LgL1 and in KRiP1 down-regulated strains. These data emphasize the unexpected role of GS in the modulation of E.histolytica virulence and the involvement of KRiP1 and Lgl1 in this phenomenon. PMID:21829737

  18. The attentional boost effect and context memory.

    PubMed

    Mulligan, Neil W; Smith, S Adam; Spataro, Pietro

    2016-04-01

    Stimuli co-occurring with targets in a detection task are better remembered than stimuli co-occurring with distractors-the attentional boost effect (ABE). The ABE is of interest because it is an exception to the usual finding that divided attention during encoding impairs memory. The effect has been demonstrated in tests of item memory but it is unclear if context memory is likewise affected. Some accounts suggest enhanced perceptual encoding or associative binding, predicting an ABE on context memory, whereas other evidence suggests a more abstract, amodal basis of the effect. In Experiment 1, context memory was assessed in terms of an intramodal perceptual detail, the font and color of the study word. Experiment 2 examined context memory cross-modally, assessing memory for the modality (visual or auditory) of the study word. Experiments 3 and 4 assessed context memory with list discrimination, in which 2 study lists are presented and participants must later remember which list (if either) a test word came from. In all experiments, item (recognition) memory was also assessed and consistently displayed a robust ABE. In contrast, the attentional-boost manipulation did not enhance context memory, whether defined in terms of visual details, study modality, or list membership. There was some evidence that the mode of responding on the detection task (motoric response as opposed to covert counting of targets) may impact context memory but there was no evidence of an effect of target detection, per se. In sum, the ABE did not occur in context memory with verbal materials. (PsycINFO Database Record PMID:26348201

  19. Near-field penetrating optical microscopy: A live cell nanoscale refractive index measurement technique for quantification of internal macromolecular density

    PubMed Central

    Strasser, Samantha Dale; Shekhawat, Gajendra; Rogers, Jeremy D.; Dravid, Vinayak P.; Taflove, Allen; Backman, Vadim

    2012-01-01

    Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to successive depths into an illuminated sample. A 50 nm diameter probe-tip collects signal that exhibits a linear relationship with the sample RI at a spatial resolution of approximately 50 nm for biologically relevant measurements, one order-of-magnitude finer than the Abbe diffraction limit. Live and fixed cell data illustrate the mechanical ability of a 50 nm probe to penetrate biological samples. PMID:22344088

  20. Near-field penetrating optical microscopy: a live cell nanoscale refractive index measurement technique for quantification of internal macromolecular density.

    PubMed

    Strasser, Samantha Dale; Shekhawat, Gajendra; Rogers, Jeremy D; Dravid, Vinayak P; Taflove, Allen; Backman, Vadim

    2012-02-15

    Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to successive depths into an illuminated sample. A 50 nm diameter probe tip collects signal that exhibits a linear relationship with the sample RI at a spatial resolution of approximately 50 nm for biologically relevant measurements, one order of magnitude finer than the Abbe diffraction limit. Live and fixed cell data illustrate the mechanical ability of a 50 nm probe to penetrate biological samples. PMID:22344088