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Sample records for boost field technique

  1. 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.

  2. Tumor bed boost radiotherapy in breast cancer. A review of current techniques.

    PubMed

    Bahadur, Yasir A; Constantinescu, Camelia T

    2012-04-01

    Various breast boost irradiation techniques were studied and compared. The most commonly used techniques are external beam radiation therapy (EBRT) (photons or electrons) and high dose rate (HDR) interstitial brachytherapy, but recent studies have also revealed the use of advanced radiotherapy techniques, such as intensity modulated radiation therapy (IMRT), intra-operative radiation therapy (IORT), tomotherapy, and protons. The purpose of this study is to systematically review the literature concerning breast boost radiotherapy techniques, and suggest evidence based guidelines for each. A search for literature was performed in the National Library of Medicine's (PubMed) database for English-language articles published from 1st January 1990 to 5th April 2011. The key words were `breast boost radiotherapy`, `breast boost irradiation`, and `breast boost irradiation AND techniques`. Randomized trials comparing the long-term results of boost irradiation techniques, balancing the local control, and cosmesis against logistic resources, and including cost-benefit analysis are further needed. PMID:22485229

  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. 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.

  6. 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

  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. PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter

    NASA Astrophysics Data System (ADS)

    Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori

    The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.

  9. 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

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

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

    DOE PAGES

    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

  18. 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.

  19. Intrusion detection: a novel approach that combines boosting genetic fuzzy classifier and data mining techniques

    NASA Astrophysics Data System (ADS)

    Ozyer, Tansel; Alhajj, Reda; Barker, Ken

    2005-03-01

    This paper proposes an intelligent intrusion detection system (IDS) which is an integrated approach that employs fuzziness and two of the well-known data mining techniques: namely classification and association rule mining. By using these two techniques, we adopted the idea of using an iterative rule learning that extracts out rules from the data set. Our final intention is to predict different behaviors in networked computers. To achieve this, we propose to use a fuzzy rule based genetic classifier. Our approach has two main stages. First, fuzzy association rule mining is applied and a large number of candidate rules are generated for each class. Then the rules pass through pre-screening mechanism in order to reduce the fuzzy rule search space. Candidate rules obtained after pre-screening are used in genetic fuzzy classifier to generate rules for the specified classes. Classes are defined as Normal, PRB-probe, DOS-denial of service, U2R-user to root and R2L- remote to local. Second, an iterative rule learning mechanism is employed for each class to find its fuzzy rules required to classify data each time a fuzzy rule is extracted and included in the system. A Boosting mechanism evaluates the weight of each data item in order to help the rule extraction mechanism focus more on data having relatively higher weight. Finally, extracted fuzzy rules having the corresponding weight values are aggregated on class basis to find the vote of each class label for each data item.

  20. Boosting the FM-Index on the GPU: Effective Techniques to Mitigate Random Memory Access.

    PubMed

    Chacón, Alejandro; Marco-Sola, Santiago; Espinosa, Antonio; Ribeca, Paolo; Moure, Juan Carlos

    2015-01-01

    The recent advent of high-throughput sequencing machines producing big amounts of short reads has boosted the interest in efficient string searching techniques. As of today, many mainstream sequence alignment software tools rely on a special data structure, called the FM-index, which allows for fast exact searches in large genomic references. However, such searches translate into a pseudo-random memory access pattern, thus making memory access the limiting factor of all computation-efficient implementations, both on CPUs and GPUs. Here, we show that several strategies can be put in place to remove the memory bottleneck on the GPU: more compact indexes can be implemented by having more threads work cooperatively on larger memory blocks, and a k-step FM-index can be used to further reduce the number of memory accesses. The combination of those and other optimisations yields an implementation that is able to process about two Gbases of queries per second on our test platform, being about 8 × faster than a comparable multi-core CPU version, and about 3 × to 5 × faster than the FM-index implementation on the GPU provided by the recently announced Nvidia NVBIO bioinformatics library. PMID:26451818

  1. 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

  2. A Reference Voltage Buffer with Settling Boost Technique for a 12bit 18MHz Multibit/Stage Pipelined A/D Converter

    NASA Astrophysics Data System (ADS)

    Okura, Shunsuke; Okura, Tetsuro; Ido, Toru; Taniguchi, Kenji

    A reference voltage buffer for a multibit/stage pipelined ADC is described, where a settling boost technique is used to improve the settling response of the pipelined stages. A 12bit 18MHz pipelined ADC with the buffer is designed and simulated based on a 0.35µm CMOS process. According to simulation results, the power consumed by the reference voltage buffer is reduced by 33% compared to that without the settling boost technique.

  3. 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.

  4. A Boosting Approach for the Detection of Faint Compact Sources in Wide Field Aperture Synthesis Radio Images

    NASA Astrophysics Data System (ADS)

    Torrent, A.; Peracaula, M.; Lladó, X.; Freixenet, J.; Sánchez-Sutil, J. R.; Paredes, J. M.; Martí, J.

    2010-12-01

    Several thresholding techniques have been proposed so far in order to perform faint compact source detection in wide field interferometric radio images. Due to their low intensity/noise ratio, some objects can be easily missed by these automatic detection methods. In this paper we present a novel approach to overcome this problem. Our proposal is based on using local features extracted from a bank of filters. These features provide a description of different types of faint source structures. Our approach performs an initial training step in order to automatically learn and select the most salient features, which are then used in a Boosting classifier to perform the detection. The validity of our method is demonstrated using 19 images that compose a 2.5°×2.5° radio mosaic, obtained with the Giant Metrewave Radio Telescope, centered on the MGRO J2019+37 peak of gamma emission at the Cygnus region. A comparison with two previously published radio catalogues of this region (task SAD of AIPS and SExtractor) is also provided.

  5. 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

  6. 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...

  7. Radiotherapeutic management and results of T1N0, T2N0 carcinoma of the oral tongue: Evaluation of boost techniques

    SciTech Connect

    Wang, C.C. )

    1989-08-01

    This paper presents the total experience of radiation therapy of early carcinoma of the oral tongue at the Massachusetts General Hospital over a span of 25 years. External beam radiotherapy with various boost techniques were used including interstitial implant, and intra-oral cone (IOC) using kilovoltage (250 kV HVL 1.53 mm Cu) radiations or low megavoltage electron beam. We evaluated our results of boost techniques for treatment of patients with T1N0 and T2N0 lesions and determined the 5-year actuarial local control rates of these treatment methods. From 1960-1978, 49 patients were treated by implant and 20 by intra-oral cone kilovoltage radiation. From 1979-1985, 73 patients were treated by intra-oral cone electron beam with minimal follow-up of 2 years. The 5-year actuarial local control rates for T1N0 and T2N0 lesions showed 54% after implant, 50% after intra-oral cone kilovoltage, and 86% after intra-oral cone electron beam boost with a p value of 0.0001. For the T1N0 lesions, the corresponding rates were 77%, 62%, and 90%, and for T2N0 lesions the rates were 54%, 43%, and 85%, respectively. In the absence of a prospective randomized trial, direct comparison of various boost techniques is not possible due to selection factor for therapy, increased clinical and technical expertise, and improvement in equipment. Therefore, no definitive conclusions can be made regarding optimum boost therapy. The data presented herein suggest that intra-oral cone electron beam boost technique is superior to interstitial implant for boosting early carcinoma of the tongue.

  8. 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…

  9. 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.

  10. 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

  11. Comparison of two techniques of interstitial pulsed dose rate boost brachytherapy in conservative treatment of breast cancer

    PubMed Central

    Tarnawska, Zofia; Blukis, Andrzej; Badzio, Andrzej; Jaskiewicz, Janusz; Jassem, Jacek

    2009-01-01

    Purpose The aim of this work is to compare selected parameters of implants and natural dose volume histograms for two techniques of interstitial pulsed dose rate brachytherapy (PDR BT) as a boost to the tumour bed in breast-conserving therapy (BCT). Material and methods Data of T1-3N0-2M0 breast cancer patients who underwent BCT with BT boost between 05.2002 and 12.2008 were analysed. Ninety two patients were implanted with rigid tubes after breast irradiation (group A) and 96 had a peri-operative BT with an intra-operative flexible tube placement and subsequent whole breast radiotherapy (group B). In both groups PDR BT of 15 Gy (1 Gy/pulse/h) was administered based on Paris system rules, and volume optimization using BT planning system PLATO. Results Three-plane implant was used in 62% and 8% of patients in group A and B, respectively, and two-plane implant in 38% of group A and in 84% of group B, with a median of 11 and 9 tubes respectively. The average volume for the prescribed dose (V100) was 42.0 ± 25.4 cc (group A) and 34.1 ± 19.7 cc (group B), respectively (p = 0.017). The individual V50 and V200 were similar. Quality index (QI) was not impacted by the technique of BT (mean QI was 1.80 ± 0.10 and 1.75 ± 0.46 for the groups A and B, respectively). Uniformity index (UI) in respective groups was 1.60 ± 0.10 and 1.52 ± 0.21 (p = 0.001). Conclusions Implant volume encompassed by prescribed dose was significantly lower with intra-operative plastic tubes placement. In respect to the QI, these two BT techniques were comparable. The target volume coverage by the dose distribution as defined by UI was better for rigid tubes.

  12. 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.

  13. 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.

  14. Boosting the accuracy of SPH techniques: Newtonian and special-relativistic tests

    NASA Astrophysics Data System (ADS)

    Rosswog, S.

    2015-04-01

    We study the impact of different discretization choices on the accuracy of smoothed particle hydrodynamics (SPH) and we explore them in a large number of Newtonian and special-relativistic benchmark tests. As a first improvement, we explore a gradient prescription that requires the (analytical) inversion of a small matrix. For a regular particle distribution, this improves gradient accuracies by approximately 10 orders of magnitude and the SPH formulations with this gradient outperform the standard approach in all benchmark tests. Secondly, we demonstrate that a simple change of the kernel function can substantially increase the accuracy of an SPH scheme. While the `standard' cubic spline kernel generally performs poorly, the best overall performance is found for a high-order Wendland kernel which allows for only very little velocity noise and enforces a very regular particle distribution, even in highly dynamical tests. Thirdly, we explore new SPH volume elements that enhance the treatment of fluid instabilities and, last, but not least, we design new dissipation triggers. They switch on near shocks and in regions where the flow - without dissipation - starts to become noisy. The resulting new SPH formulation yields excellent results even in challenging tests where standard techniques fail completely.

  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. 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

  18. 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.

  19. Ototoxicity evaluation in medulloblastoma patients treated with involved field boost using intensity-modulated radiation therapy (IMRT): a retrospective review

    PubMed Central

    2014-01-01

    Background Ototoxicity is a known side effect of combined radiation therapy and cisplatin chemotherapy for the treatment of medulloblastoma. The delivery of an involved field boost by intensity modulated radiation therapy (IMRT) may reduce the dose to the inner ear when compared with conventional radiotherapy. The dose of cisplatin may also affect the risk of ototoxicity. A retrospective study was performed to evaluate the impact of involved field boost using IMRT and cisplatin dose on the rate of ototoxicity. Methods Data from 41 medulloblastoma patients treated with IMRT were collected. Overall and disease-free survival rates were calculated by Kaplan-Meier method Hearing function was graded according to toxicity criteria of Pediatric Oncology Group (POG). Doses to inner ear and total cisplatin dose were correlated with hearing function by univariate and multivariate data analysis. Results After a mean follow-up of 44 months (range: 14 to 72 months), 37 patients remained alive, with two recurrences, both in spine with CSF involvement, resulting in a disease free-survival and overall survival of 85.2% and 90.2%, respectively. Seven patients (17%) experienced POG Grade 3 or 4 toxicity. Cisplatin dose was a significant factor for hearing loss in univariate analysis (p < 0.03). In multivariate analysis, median dose to inner ear was significantly associated with hearing loss (p < 0.01). POG grade 3 and 4 toxicity were uncommon with median doses to the inner ear bellow 42 Gy (p < 0.05) and total cisplatin dose of less than 375 mg/m2 (p < 0.01). Conclusions IMRT leads to a low rate of severe ototoxicity. Median radiation dose to auditory apparatus should be kept below 42 Gy. Cisplatin doses should not exceed 375 mg/m2. PMID:25041714

  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. Fibre based integral field unit constructional techniques

    NASA Astrophysics Data System (ADS)

    Murray, Graham J.

    2006-06-01

    Presented here is a selected overview of constructional techniques and principles that have been developed and implemented at the University of Durham in the manufacture of successful fibre-based integral field units. The information contained herein is specifically intended to highlight the constructional methods that have been devised to assemble an efficient fibre bundle. Potential pitfalls that need to be considered when embarking upon such a deceptively simple instrument are also discussed.

  2. 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.

  3. 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.

  4. 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

  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.

  6. 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.

  7. Emerging Techniques for Field Device Security

    DOE PAGES

    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

  8. 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.

  9. 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

  10. Electron energy boosting in laser-wake-field acceleration with external magnetic field B˜1 T and laser prepulses

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    Hundred-mega-electron-volt electron beams with quasi-monoenergetic distribution, and a transverse geometrical emittance as small as ˜0.02 π 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, B˜1 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.

  11. 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.

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

    PubMed

    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 Dmax 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.

  13. 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

  14. 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…

  15. 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.

  16. Esophageal gel-shifting technique facilitating eradicative boost or reirradiation to upper mediastinal targets of recurrent nerve lymph node without damaging esophagus

    PubMed Central

    Kishi, Kazushi; Iida, Takeshi; Ojima, Toshiyasu; Sonomura, Tetsuo; Shirai, Shintaro; Nakai, Motoki; Sato, Morio; Yamaue, Hiroki

    2013-01-01

    We developed a new technique using hyaluronic gel injection as a spacer to safely move the esophagus away from the high-dose area during interstitial brachytherapy of a mediastinal target close to the esophagus. We percutaneously injected a high-molecular-weight hyaluronic gel mixed with contrast medium to create a space between the esophagus and the target during interstitial brachytherapy. We applied this technique to two cases of relapsed recurrent nerve lymph node metastasis from esophageal cancer: one refractory tumor after 50 Gy of radiotherapy, and one recurrence after mediastinal radiotherapy of total 64 Gy. We prescribed 20 Gy and 18 Gy in one fraction to each target, with calculated esophageal D2cc (the minimum dose to the most irradiated volume of 2 cc) of 4.0 Gy and 6.8 Gy, respectively. Calculated enhancement factor by gel shifting in equivalent dose was 2.69 and 2.34, respectively. In each patient, accumulated esophageal D1cc (minimum dose to the most irradiated volume of p cc. minimum dose to the most irradiated volume of 1 cc) was 74.4 Gy and 85.6 Gy without shifting, and 59.1 Gy and 37.6 Gy with shifting, respectively. There were no procedure-related complications. Four months after the brachytherapy, each tumor was remarkably diminished. No evidence of recurrences or late complications were observed 8 months and 9 months after the procedure, respectively. The esophageal gel-shifting technique may facilitate eradicative brachytherapy to upper mediastinal targets without damaging the esophagus, and can be used in conjunction with boost irradiation or reirradiation to overcome the problem of salvage failure. PMID:23436229

  17. 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

  18. 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

  19. Representing Arbitrary Boosts for Undergraduates.

    ERIC Educational Resources Information Center

    Frahm, Charles P.

    1979-01-01

    Presented is a derivation for the matrix representation of an arbitrary boost, a Lorentz transformation without rotation, suitable for undergraduate students with modest backgrounds in mathematics and relativity. The derivation uses standard vector and matrix techniques along with the well-known form for a special Lorentz transformation. (BT)

  20. 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…

  1. A color video display technique for flow field surveys

    NASA Technical Reports Server (NTRS)

    Winkelmann, A. E.; Tsao, C. P.

    1982-01-01

    Color video display techniques for flow field surveys are presented. The following techniques were examined: traverse device, used for flow field surveys above and behind finite wing models; flow chart of data reduction for color video display technique; location of spanwise survey stations above and behind wing; hot wire data at first three survey stations on fully stalled wing; hot wire data at last three stations behind fully stalled wing; hot wire and pitch probe data; magnitude of velocity, yaw angle, pitch angle, and cross flow direction from 5 tube survey at X/C = 2.70 behind fully stalled wing.

  2. 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.

  3. Adaptive near-field beamforming techniques for sound source imaging.

    PubMed

    Cho, Yong Thung; Roan, Michael J

    2009-02-01

    Phased array signal processing techniques such as beamforming have a long history in applications such as sonar for detection and localization of far-field sound sources. Two sometimes competing challenges arise in any type of spatial processing; these are to minimize contributions from directions other than the look direction and minimize the width of the main lobe. To tackle this problem a large body of work has been devoted to the development of adaptive procedures that attempt to minimize side lobe contributions to the spatial processor output. In this paper, two adaptive beamforming procedures-minimum variance distorsionless response and weight optimization to minimize maximum side lobes--are modified for use in source visualization applications to estimate beamforming pressure and intensity using near-field pressure measurements. These adaptive techniques are compared to a fixed near-field focusing technique (both techniques use near-field beamforming weightings focusing at source locations estimated based on spherical wave array manifold vectors with spatial windows). Sound source resolution accuracies of near-field imaging procedures with different weighting strategies are compared using numerical simulations both in anechoic and reverberant environments with random measurement noise. Also, experimental results are given for near-field sound pressure measurements of an enclosed loudspeaker.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. 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,…

  13. 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.

  14. 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.

  15. A Simple Technique for Visualizing Ultrasound Fields Without Schlieren Optics.

    PubMed

    Kudo, Nobuki

    2015-07-01

    A simple technique designed for visualization of ultrasound fields without Schlieren optics is introduced. An optical system of direct shadowgraphy with diverging light, which consists of a point light source and a shadow screen, constituted the basic system, but the screen was replaced by focusing optics: a camera that makes a virtual screen at its focus plane. The proposed technique visualizes displacement of light deflected by ultrasound, and the use of focusing optics enables flexible settings of the virtual screen position and optical magnification. Insufficient sensitivity of shadowgraphy was overcome by elimination of non-deflecting light using image subtraction of shadowgrams taken with and without ultrasound exposure. A 1-MHz focused transducer for ultrasound therapy and a 20-MHz miniature transducer for intravascular imaging were used for experiments, and alternate pressure change in short-pulsed ultrasound was visualized, indicating the usefulness of the proposed technique for evaluation of medical ultrasound fields.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Integration of Field and Remote Sensing Techniques For Landslides Monitoring

    NASA Astrophysics Data System (ADS)

    Allievi, J.; Ambrosi, C.; Ceriani, M.; Colesanti, C.; Crosta, G. B.; Ferretti, A.; Fossati, D.; Menegaz, A.

    The definition of the state of activity of slope movements is of major interest both at local and at regional scale. The Geological Survey of the Regione Lombardia has re- cently started a series of projects aimed to the identification of areas subjected to slope instability and to the assessment of their state of activity. Field survey, aerial photo interpretation and advanced remote sensing techniques have been applied. Some ex- amples of large rock slope instabilities have been investigated in the Valtellina area (Lombardia, Northern Italy). In particular, we demonstrate the degree of integration of the adopted techniques for one of the largest rock slope movements actually recog- nised in the area. The remote sensing approach that has been adopted is the Perma- nent Scatterers (PS) Technique. This technique has been recently developed as a new methodology for surface deformation monitoring, using ESA ERS-SAR data. Its ap- plication to large slope movements in alpine and prealpine areas, with a relatively low urban development, has been tried for the first time in order to evaluate its potential in supporting studies for landslide hazard assessment. Previous results show that this ap- proach allows to reach an accuracy very close to the theoretical limit. This study shows the very good agreement reached for displacement velocities between historical trends and recent PS measurements. Scatterers have been identified by field surveying and some of them are located close to historically monitored benchmark for topographic measurements. Furthermore, the integration of these data with field observations al- lowed us to perform a preliminary reconstrucion of the landslide mechanism and to assess the activity of different landslide structures (scarps, etc.).

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Octane boosting catalyst

    SciTech Connect

    Miller, J.G.; Pellet, R.J.; Shamshoun, E.S.; Rabo, J.A

    1989-02-07

    The invention provides petroleum cracking and octane boosting catalysts containing a composite of an intermediate pore NZMS in combination with another non-zeolitic molecular sieve having the same framework structure, and processes for cracking of petroleum for the purpose of enhancing the octane rating of the gasoline produced.

  11. 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.

  12. Tracking down hyper-boosted top quarks

    DOE PAGES

    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

  13. Tracking down hyper-boosted top quarks

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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. Our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  14. A field experiment comparing different workgroup interactive techniques.

    PubMed

    Eisele, Per

    2007-02-01

    Participants (N=149) belonging to real life workgroups from different work organisations took part in a project with the aim of improving organisational culture. Two techniques for enhancing effectiveness were used in the study, the individual-group-individual technique and the nominal group technique. In a control group were participants in nonstructured interactive groups. Thus, the workgroups were randomised into these 3 conditions. Analysis indicated that both techniques affect idea generation but not generation of goals.

  15. 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

  16. Process Concerns In Use of Force Field Techniques.

    ERIC Educational Resources Information Center

    Giammatteo, Michael C.

    This paper, one of a series derived from techniques used in training student teachers, explores the process of manipulating the variables in a problem or conflict or challenge situation. Specifically, it explores interpersonal feelings, intrapersonal feelings and conflicts that occur when these two are not in harmony. The technique calls upon the…

  17. 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.

  18. 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).

  19. Gravity field, geoid and ocean surface by space techniques

    NASA Technical Reports Server (NTRS)

    Anderle, R. J.

    1978-01-01

    Knowledge of the earth's gravity field continued to increase during the last four years. Altimetry data from the GEOS-3 satellite has provided the geoid over most of the ocean to an accuracy of about one meter. Increasing amounts of laser data has permitted the solution for 566 terms in the gravity field with which orbits of the GEOS-3 satellite have been computed to an accuracy of about one to two meters. The combination of satellite tracking data, altimetry and gravimetry has yielded a solution for 1360 terms in the earth's gravity field. A number of problems remain to be solved to increase the accuracy of the gravity field determination. New satellite systems would provide gravity data in unsurveyed areas and correction for topographic features of the ocean and improved computational procedures together with a more extensive laser network will considerably improve the accuracy of the results.

  20. 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.

  1. 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 ...

  2. 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.

  3. Analytic boosted boson discrimination

    DOE PAGES

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

    2016-05-20

    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, D2, 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.more » 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. In conclusion, our calculation also provides considerable insight into the discrimination power and calculability of jet substructure observables in general.« less

  4. Culture control in crop fields: A habitat management technique

    NASA Astrophysics Data System (ADS)

    Mayse, Mark A.

    1983-01-01

    Cultural factors, including vegetational backgrounds adjacent to and/or within the crop, harvest procedures, crop rotation patterns, planting dates, and plant density/spacing patterns provide a major portion of the ecological context in which arthropod populations in crop fields exist These cropping practices can often be manipulated to help favorably manage arthropod populations Some research highlights involving various types of cultural control are presented, including a discussion of several problems faced by researchers investigating cultural control of arthropods in field crop agroecosystems. In order to understand the complexities involved in cultural factor effects on arthropod populations, investigators must perform carefully designed research. Also, the most appropriate and meaningful way(s) to express arthropod population levels in such studies must be critically determined

  5. 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…

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Hybrid single-beam reconstruction technique for slow and fast varying wave fields.

    PubMed

    Falaggis, Konstantinos; Kozacki, Tomasz; Kujawinska, Malgorzata

    2015-06-01

    An iterative single-beam wave field reconstruction technique that employs both non-paraxial, wave propagation based and paraxial deterministic phase retrieval techniques is presented. This approach overcomes two major obstacles that exist in the current state of the art techniques: iterative methods do not reconstruct slowly varying wave fields due to slow convergence and stagnation, and deterministic methods have paraxial limits, making the reconstructions of quickly varying object features impossible. In this work, a hybrid approach is reported that uses paraxial wave field corrections within iterative phase retrieval solvers. This technique is suitable for cases ranging from slow to fast varying wave fields, and unlike the currently available methods, can also reconstruct measurement objects with different regions of both slowly and quickly varying object features. It is further shown that this technique gives a higher accuracy than current single-beam phase retrieval techniques, and in comparison to the iterative methods, has a higher convergence speed.

  11. Full-field laser vibration measurement in NDT techniques

    NASA Astrophysics Data System (ADS)

    Yue, Kaiduan; Li, Zhongke; Yi, Yaxing; Zhang, Fei

    2008-12-01

    Research of Non Destructive Testing (NDT) methodology has developed rapidly in recent years[1][2]. But it is rarely used for small objects such as Micro-electronic Mechanics System. Due to the small size of the MEMS, the traditional method of contact measurement seriously affects the parameter of the object measured. So a high accuracy non-contact measurement is required for optimization of MEMS designs and improvement of its reliability[3][4]. With recent advances in photonics, electronics, and computer technology, a Non Destructive Testing (NDT) laser time average interferometry is proposed in the paper. Laser interferometry has the advantages of non-contact, high accuracy, full-field and fast speed, so it can be used to detect cracks in MEMS. A time average measurement method of digital speckle pattern interferometry is proposed to measure the vibration mode of the MEMS in the paper. According to the sudden change of amplitude of vibration mode, a crack can be measured. With the speckle average technology, high accuracy phase-shift, continuous phase scanning technology, combined with optical amplification technology, the resolution of the amplitude reaches 1nm, and the resolution of the crack reaches 5μm. The measurement system being full-field, the measuring speed of the measurement system can reach 512*512 points per one minute.

  12. An equivalent source technique for recovering the free sound field in a noisy environment.

    PubMed

    Bi, Chuan-Xing; Bolton, J Stuart

    2012-02-01

    In previous studies, a sound field separation technique based on the equivalent source method (ESM) was successfully applied to separate the incoming and outgoing fields composing a non-free field. However, if the incoming wave is scattered by the source surface, the outgoing field is not the field that would be generated by the source in a free field. The object of the present work was to provide an equivalent source technique that allows the recovery of that free field in a noisy environment. In this approach, the incoming and outgoing fields, including the scattered and directly radiated fields on the measurement surface, are separated to obtain the free-field pressure that would be radiated by the source in an anechoic environment. The recovered free-field pressure is then used to reconstruct the whole free field of the source by using near-field acoustical holography based on the ESM, which makes the results equivalent to those that could be obtained from a free-field measurement. A theoretical description of the technique is given first, and then three numerical cases are investigated to demonstrate the ability of the proposed method.

  13. 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

  14. Applications of Effective Field Theory Techniques to Jet Physics

    NASA Astrophysics Data System (ADS)

    Freedman, Simon M.

    In this thesis we study jet production at large energies from leptonic collisions. We use the framework of effective theories of Quantum Chromodynamics (QCD) to examine the properties of jets and systematically improve calculations. We first develop a new formulation of soft-collinear effective theory (SCET), the appropriate effective theory for jets. In this formulation, soft and collinear degrees of freedom are described using QCD fields that interact with each other through light-like Wilson lines in external currents. This formulation gives a more intuitive picture of jet processes than the traditional formulation of SCET. In particular, we show how the decoupling of soft and collinear degrees of freedom that occurs at leading order in power counting is explicit to next-to-leading order and likely beyond. We then use this formulation to write the thrust rate in a factorized form at next-to-leading order in the thrust parameter. The rate involves an incomplete sum over final states due to phase space cuts that is enforced by a measurement operator. Subleading corrections require matching onto not only the next-to-next-to leading order SCET operators, but also matching onto subleading measurement operators. We derive the appropriate hard, jet, and soft functions and show they reproduce the expected subleading thrust rate. Next, we renormalize the next-to-leading order dijet operators used for the subleading thrust rate. Constraints on matching coefficients from current conservation and reparametrization invariance are shown. We also discuss the subtleties involved in regulating the infrared divergences of the individual loop diagrams in order to extract the ultraviolet divergences. The results can be used to increase the theoretical precision of the thrust rate. Finally, we study the (exclusive) k_perp and C/A jet algorithms in SCET. Regularizing the virtualites and rapidities of the individual graphs, we are able to write the order(alpha_s) dijet cross section

  15. Applications of Effective Field Theory Techniques to Jet Physics

    NASA Astrophysics Data System (ADS)

    Freedman, Simon M.

    In this thesis we study jet production at large energies from leptonic collisions. We use the framework of effective theories of Quantum Chromodynamics (QCD) to examine the properties of jets and systematically improve calculations. We first develop a new formulation of soft-collinear effective theory (SCET), the appropriate effective theory for jets. In this formulation, soft and collinear degrees of freedom are described using QCD fields that interact with each other through light-like Wilson lines in external currents. This formulation gives a more intuitive picture of jet processes than the traditional formulation of SCET. In particular, we show how the decoupling of soft and collinear degrees of freedom that occurs at leading order in power counting is explicit to next-to-leading order and likely beyond. We then use this formulation to write the thrust rate in a factorized form at next-to-leading order in the thrust parameter. The rate involves an incomplete sum over final states due to phase space cuts that is enforced by a measurement operator. Subleading corrections require matching onto not only the next-to-next-to leading order SCET operators, but also matching onto subleading measurement operators. We derive the appropriate hard, jet, and soft functions and show they reproduce the expected subleading thrust rate. Next, we renormalize the next-to-leading order dijet operators used for the subleading thrust rate. Constraints on matching coefficients from current conservation and reparametrization invariance are shown. We also discuss the subtleties involved in regulating the infrared divergences of the individual loop diagrams in order to extract the ultraviolet divergences. The results can be used to increase the theoretical precision of the thrust rate. Finally, we study the (exclusive) k⊥ and C/A jet algorithms in SCET. Regularizing the virtualities and rapidities of the individual graphs, we are able to write the O(alpha s) dijet cross section as the

  16. [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

  17. [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.

  18. DPSM technique for ultrasonic field modelling near fluid-solid interface.

    PubMed

    Banerjee, Sourav; Kundu, Tribikram; Alnuaimi, Nasser A

    2007-06-01

    Distributed point source method (DPSM) is gradually gaining popularity in the field of non-destructive evaluation (NDE). DPSM is a semi-analytical technique that can be used to calculate the ultrasonic fields produced by transducers of finite dimension placed in homogeneous or non-homogeneous media. This technique has been already used to model ultrasonic fields in homogeneous and multi-layered fluid structures. In this paper the method is extended to model the ultrasonic fields generated in both fluid and solid media near a fluid-solid interface when the transducer is placed in the fluid half-space near the interface. Most results in this paper are generated by the newly developed DPSM technique that requires matrix inversion. This technique is identified as the matrix inversion based DPSM technique. Some of these results are compared with the results produced by the Rayleigh-Sommerfield integral based DPSM technique. Theory behind both matrix inversion based and Rayleigh-Sommerfield integral based DPSM techniques is presented in this paper. The matrix inversion based DPSM technique is found to be very efficient for computing the ultrasonic field in non-homogeneous materials. One objective of this study is to model ultrasonic fields in both solids and fluids generated by the leaky Rayleigh wave when finite size transducers are inclined at Rayleigh critical angles. This phenomenon has been correctly modelled by the technique. It should be mentioned here that techniques based on paraxial assumptions fail to model the critical reflection phenomenon. Other advantages of the DPSM technique compared to the currently available techniques for transducer radiation modelling are discussed in the paper under Introduction.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Exposure fusion using boosting Laplacian pyramid.

    PubMed

    Shen, Jianbing; Zhao, Ying; Yan, Shuicheng; Li, Xuelong

    2014-09-01

    This paper proposes a new exposure fusion approach for producing a high quality image result from multiple exposure images. Based on the local weight and global weight by considering the exposure quality measurement between different exposure images, and the just noticeable distortion-based saliency weight, a novel hybrid exposure weight measurement is developed. This new hybrid weight is guided not only by a single image's exposure level but also by the relative exposure level between different exposure images. The core of the approach is our novel boosting Laplacian pyramid, which is based on the structure of boosting the detail and base signal, respectively, and the boosting process is guided by the proposed exposure weight. Our approach can effectively blend the multiple exposure images for static scenes while preserving both color appearance and texture structure. Our experimental results demonstrate that the proposed approach successfully produces visually pleasing exposure fusion images with better color appearance and more texture details than the existing exposure fusion techniques and tone mapping operators. PMID:25137687

  5. Reconstruction of Unsteady and Axisymmetric Flow Field by Colored-Grid Background Oriented Schlieren (CGBOS) Technique

    NASA Astrophysics Data System (ADS)

    Ota, M.; Leopold, F.; Jagusinski, F.; Maeno, K.

    The Background Oriented Schlieren (BOS) technique was proposed by Meier [1], and it enables us to take a quantitative density measurement of a flow field with computer-aided image analysis. In the past several years, the BOS technique was applied in various experiments [2],[3].

  6. 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.

  7. Sound field separation technique based on equivalent source method and its application in nearfield acoustic holography.

    PubMed

    Bi, Chuan-Xing; Chen, Xin-Zhao; Chen, Jian

    2008-03-01

    A technique for separating sound fields using two closely spaced parallel measurement surfaces and based on equivalent source method is proposed. The method can separate wave components crossing two measurement surfaces in opposite directions, which makes nearfield acoustic holography (NAH) applications in a field where there exist sources on the two sides of the hologram surface, in a reverberant field or in a scattered field, possible. The method is flexible in applications, simple in computation, and very easy to implement. The measurement surfaces can be arbitrarily shaped, and they are not restricted to be regular as in the traditional field separation technique. And, because the method performs field separation calculations directly in the spatial domain-not in the wave number domain--it avoids the errors and limitations (the window effects, etc.) associated with the traditional field separation technique based on the spatial Fourier transform method. In the paper, a theoretical description is first given, and the performance of the proposed field separation technique and its application in NAH are then evaluated through experiments.

  8. Course in Biometeorological Field Techniques. Final Report to National Science Foundation.

    ERIC Educational Resources Information Center

    Tanner, C. B.

    This is the final report to the National Science Foundation (NSF) from a grant to develop a course in biometeorological field techniques. Objectives of the course were to give students experiences in making field measurements of parameters of the physical environment and their impact on plants and animals; and to develop an understanding of the…

  9. 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.…

  10. An optical leveling technique for parallel near-field photolithography system

    NASA Astrophysics Data System (ADS)

    Liu, Zhuming; Chen, Xinyong; Zhang, Yuan; Weaver, John; Roberts, Clive J.

    2012-10-01

    An optical leveling technique is reported for a compact parallel (multi-cantilever) scanning near-field photolithography (SNP) prototype. This instrument operates in liquid and was designed to overcome the challenge of low sample throughput of previous serial scanning SNPs. A combination of zone plate lens array, probe array, and standard atomic force microscope feedback technique are employed to deliver parallel probe operation in the current SNP. Compared to the commonly used two-end or multi-end "force feedback" alignment techniques, the optical levelling technique applied provides a simple solution to maintaining all levers in an array within the near-field region. As a proof-of-principle experiment, the operation of the prototype was demonstrated by producing nano-scale patterns in parallel using scanning near-field photolithography.

  11. 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.

  12. 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.

  13. New equations for matching a low neck field to oblique upper neck fields with collimator rotation in a 3-field monoisocentric setup for head-and-neck cancers.

    PubMed

    Manske, Maria A; Barker, Jerry L; Wong, Pei-Fong; Westlake, Wallace; Garden, Adam S; Ang, K Kian; Rosenthal, David I

    2004-01-01

    With a monoisocentric 3-field technique for treating head-and-neck cancer, collimator rotation may be needed for the upper lateral fields to avoid cephalad-positioned shoulders or to avoid unnecessary arytenoid irradiation while maintaining more anterior coverage. For patients with unilateral lymphadenopathy, lateral oblique-opposed boost fields can be used to encompass the primary tumor and ipsilateral lymph nodes without junctioning through gross disease. When initial collimated lateral fields are also rotated with a gantry angle to produce oblique boost fields, however, the resulting matchline with a low anterior neck (LAN) boost field is no longer nondivergent. This can be corrected by manual adjustment of collimator and gantry angles for the LAN field using 3D treatment planning software. The goal of this study was to derive mathematical formulas to simplify this process. We used a transformation matrix to define formulas that could predict the appropriate modifications to the LAN boost field. Output from the formulas was (1) visually tested within 3D treatment planning software and (2) verified using a solid water head-and-neck phantom and radiographic film dosimetry to confirm that a nondivergent matchline was obtained in several clinical scenarios. When evaluated with 3D treatment planning software, the formulas accurately predicted the appropriate gantry and collimator angles of the LAN boost field for a variety of possible beam combinations. When evaluated with film dosimetry, the formulas were shown to accurately predict the appropriate gantry and collimator angles of the LAN boost field to within the +/- 2 mm/1 degrees tolerance specifications of the linear accelerator and acceptable for routine clinical use. The presented formulas are simple and geometrically precise. They predict the necessary manipulations of the LAN boost field to maintain a geometrically precise matchline, as verified by 3D treatment planning software, phantom dosimetry, and actual

  14. 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

  15. Boost covariant gluon distributions in large nuclei

    NASA Astrophysics Data System (ADS)

    McLerran, Larry; Venugopalan, Raju

    1998-04-01

    It has been shown recently that there exist analytical solutions of the Yang-Mills equations for non-Abelian Weizsäcker-Williams fields which describe the distribution of gluons in large nuclei at small x. These solutions however depend on the color charge distribution at large rapidities. We here construct a model of the color charge distribution of partons in the fragmentation region and use it to compute the boost covariant momentum distributions of wee gluons. The phenomenological applications of our results are discussed.

  16. 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.

  17. 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.

  18. Breast Conserving Treatment for Breast Cancer: Dosimetric Comparison of Sequential versus Simultaneous Integrated Photon Boost

    PubMed Central

    Reynders, Truus; Heuninckx, Karina; Verellen, Dirk; Storme, Guy; De Ridder, Mark

    2014-01-01

    Background. Breast conserving surgery followed by whole breast irradiation is widely accepted as standard of care for early breast cancer. Addition of a boost dose to the initial tumor area further reduces local recurrences. We investigated the dosimetric benefits of a simultaneously integrated boost (SIB) compared to a sequential boost to hypofractionate the boost volume, while maintaining normofractionation on the breast. Methods. For 10 patients 4 treatment plans were deployed, 1 with a sequential photon boost, and 3 with different SIB techniques: on a conventional linear accelerator, helical TomoTherapy, and static TomoDirect. Dosimetric comparison was performed. Results. PTV-coverage was good in all techniques. Conformity was better with all SIB techniques compared to sequential boost (P = 0.0001). There was less dose spilling to the ipsilateral breast outside the PTVboost (P = 0.04). The dose to the organs at risk (OAR) was not influenced by SIB compared to sequential boost. Helical TomoTherapy showed a higher mean dose to the contralateral breast, but less than 5 Gy for each patient. Conclusions. SIB showed less dose spilling within the breast and equal dose to OAR compared to sequential boost. Both helical TomoTherapy and the conventional technique delivered acceptable dosimetry. SIB seems a safe alternative and can be implemented in clinical routine. PMID:25162031

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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).

  6. Investigating damage fields in a particulate composite material using real-time x-ray technique

    SciTech Connect

    Liu, C.T.; Tang, B.

    1993-12-31

    The damage fields in an edge-cracked sheet specimen subjected to a constant crosshead speed were investigated using the real-time x-ray technique. The specimen was made from polybutadiene rubber embedded with hard particles. The x-ray data were analyzed to delineate the damage field near the crack tip and to generate contour plots of the damage intensity. The experimental data were analyzed and the results are discussed.

  7. 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.

  8. Near-field three-dimensional radar imaging techniques and applications.

    PubMed

    Sheen, David; McMakin, Douglas; Hall, Thomas

    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 nondestructive 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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…

  15. 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…

  16. 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…

  17. A Comparison of Three C-Arm Draping Techniques to Minimize Contamination of the Surgical Field.

    PubMed

    Gershkovich, Grigory E; Tiedeken, Nathan C; Hampton, David; Budacki, Ross; Samuel, Solomon P; Saing, Minn

    2016-10-01

    The use of intraoperative fluoroscopy has become a routine and useful adjunct within orthopaedic surgery. However, the fluoroscopy machine may become an additional source of contamination in the operating room, particularly when maneuvering from the anterior-posterior position to the lateral position. Consequently, draping techniques were developed to maintain sterility of the operative field and surgeon. Despite a variety of methods, no studies exist to compare the sterility of these techniques specifically when the fluoroscopy machine is in the lateral imaging position. We evaluated the sterility of 3 c-arm draping techniques in a simulated operative environment. The 3 techniques consisted of a traditional 3-quarter sterile sheet attached to the side of the operative table, a modified clip-drape method, and a commercially available sterile pouch. Our study demonstrated that the traditional method poses a high risk for sterile field contamination, whereas the modified clip-drape method and commercially available sterile pouch kept floor contamination furthest from the surgical field. With the current data, we urge surgeons to use modified techniques rather than the traditional draping method.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Reconstruction of the density field using the Colored Background Oriented Schlieren Technique (CBOS)

    NASA Astrophysics Data System (ADS)

    Sourgen, F.; Leopold, F.; Klatt, D.

    2012-01-01

    In this paper the improved Background Oriented Schlieren technique called CBOS (Colored Background Oriented Schlieren) is described and used to reconstruct density fields of three-dimensional flows. The Background Oriented Schlieren technique (BOS) allows to measure the light deflection caused by density gradients in a compressible flow. For this purpose the local image displacements of the image of a background pattern observed through the flow is used. In order to increase the performance of the conventional Background Oriented Schlieren technique, the monochromatic background is replaced by a colored dot pattern. The different colors are treated separately using suitable correlation algorithms. Therefore, the accuracy and the spatial resolution can be increased. A tomographic reconstruction method is then used to reconstruct the density field in three-dimensional flows from CBOS measurements.

  3. [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.

  4. 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.

  5. [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

  6. 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.

  7. 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.

  8. 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.

  9. Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

    NASA Astrophysics Data System (ADS)

    Eriksson, A. I.; André, M.; Klecker, B.; Laakso, H.; Lindqvist, P.-A.; Mozer, F.; Paschmann, G.; Pedersen, A.; Quinn, J.; Torbert, R.; Torkar, K.; Vaith, H.

    2006-03-01

    The four Cluster satellites each carry two instruments designed for measuring the electric field: a double-probe instrument (EFW) and an electron drift instrument (EDI). We compare data from the two instruments in a representative sample of plasma regions. The complementary merits and weaknesses of the two techniques are illustrated. EDI operations are confined to regions of magnetic fields above 30 nT and where wave activity and keV electron fluxes are not too high, while EFW can provide data everywhere, and can go far higher in sampling frequency than EDI. On the other hand, the EDI technique is immune to variations in the low energy plasma, while EFW sometimes detects significant nongeophysical electric fields, particularly in regions with drifting plasma, with ion energy (in eV) below the spacecraft potential (in volts). We show that the polar cap is a particularly intricate region for the double-probe technique, where large nongeophysical fields regularly contaminate EFW measurments of the DC electric field. We present a model explaining this in terms of enhanced cold plasma wake effects appearing when the ion flow energy is higher than the thermal energy but below the spacecraft potential multiplied by the ion charge. We suggest that these conditions, which are typical of the polar wind and occur sporadically in other regions containing a significant low energy ion population, cause a large cold plasma wake behind the spacecraft, resulting in spurious electric fields in EFW data. This interpretation is supported by an analysis of the direction of the spurious electric field, and by showing that use of active potential control alleviates the situation.

  10. 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

  11. 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.

  12. Magnetic field tunable small-scale mechanical properties of nickel single crystals measured by nanoindentation technique.

    PubMed

    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.

  13. 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.

  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. Observation of the local field distribution in photonic crystal microcavity by SNOM technique

    NASA Astrophysics Data System (ADS)

    Maidykovski, Anton I.; Lebedev, Oleg V.; Dolgova, Tatyana V.; Kazantsev, D. V.; Fedyanin, Andrew A.

    2002-11-01

    The spatial distribution of the local optical field at the cleavage of photonic crystal smicrocavity has been obtained by the scanning near-field optical microscope (SNOM). The localization of optical radiation at microcavity resonant wavelength in the vicinity of the λ/2 spacer layer is demonstrated. Samples of photonic crystal microcavity are prepared from silicon wafer by electrochemical etching technique. The wavelength of the microcavity mode is optimized for resonance with wavelengths of lasers. The image of the spatial distribution of optical field at the cleaved edge of the facing vertically microcavity is observed. Sample is pumped through external single-mode fiber perpendicularly to the microcavity. SNOM operates in the collection mode with the apertureless tip. We observe the localization of the resonant optical field in microcavity but we do not reveal such localization of the radiation at the non-resonant wavelength.

  16. 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

  17. Boosting Shift-Invariant Features

    NASA Astrophysics Data System (ADS)

    Hörnlein, Thomas; Jähne, Bernd

    This work presents a novel method for training shift-invariant features using a Boosting framework. Features performing local convolutions followed by subsampling are used to achieve shift-invariance. Other systems using this type of features, e.g. Convolutional Neural Networks, use complex feed-forward networks with multiple layers. In contrast, the proposed system adds features one at a time using smoothing spline base classifiers. Feature training optimizes base classifier costs. Boosting sample-reweighting ensures features to be both descriptive and independent. Our system has a lower number of design parameters as comparable systems, so adapting the system to new problems is simple. Also, the stage-wise training makes it very scalable. Experimental results show the competitiveness of our approach.

  18. 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.

  19. 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.

  20. Online boosting for vehicle detection.

    PubMed

    Chang, Wen-Chung; Cho, Chih-Wei

    2010-06-01

    This paper presents a real-time vision-based vehicle detection system employing an online boosting algorithm. It is an online AdaBoost approach for a cascade of strong classifiers instead of a single strong classifier. Most existing cascades of classifiers must be trained offline and cannot effectively be updated when online tuning is required. The idea is to develop a cascade of strong classifiers for vehicle detection that is capable of being online trained in response to changing traffic environments. To make the online algorithm tractable, the proposed system must efficiently tune parameters based on incoming images and up-to-date performance of each weak classifier. The proposed online boosting method can improve system adaptability and accuracy to deal with novel types of vehicles and unfamiliar environments, whereas existing offline methods rely much more on extensive training processes to reach comparable results and cannot further be updated online. Our approach has been successfully validated in real traffic environments by performing experiments with an onboard charge-coupled-device camera in a roadway vehicle.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Imaging electron density and magnetic field distributions in the magnetosphere: A new technique

    NASA Astrophysics Data System (ADS)

    Ganguly, S.; Van Bavel, G. H.; Brown, A.

    2000-07-01

    The current collection of magnetospheric observations consists almost entirely of in situ measurements at isolated spacecraft positions. A novel remote sensing technique for simultaneously imaging the plasma density N and the magnetic field B is proposed. The imaged region of the magnetosphere can be several Earth radii in extent. Simultaneous measurements of both group delay and Faraday rotation of radio waves propagating through the magnetosphere yield both total electron content (TEC) and Faraday rotation angle, which is the integral of electron density weighted by some known function of the magnetic field and ray path. These data can then be inverted to obtain estimates of the three-dimensional spatial distribution of N and B. The geometry of the ray paths determines the number of components of B that can be resolved. Simple multisatellite simulations and common data processing techniques introduce this new application of tomography: Magnetospheric TEC measurements yield a map of N, which is then combined with Faraday rotation angle measurements to produce a two-component map of B in the plane of observation. The successful tomographic reconstructions provide a straightforward illustration of the practicality of using this technique to map the magnetospheric plasma density and magnetic field in two or three dimensions. Furthermore, simultaneous images of N and B are of great topical interest to geospace science because of their direct and immediate relevance to current questions regarding magnetospheric structure and dynamics.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Harmonic generation at high field strengths - Frequency shifts and saturation phenomena. [optical mixing technique

    NASA Technical Reports Server (NTRS)

    Stappaerts, E. A.

    1975-01-01

    Optical harmonic generation and mixing in the gas phase has been proposed as a technique for the generation of coherent radiation in the vacuum ultraviolet and soft X-ray spectral region. At the high field strengths required by these processes the interaction between atoms and the electromagnetic field shows intensity-dependent resonances. In this paper we modify harmonic generation theory to include the effect of these frequency shifts. Closed-form expressions for generated dipole moment, absorption probability, and coherence length are presented. The most important consequences of frequency shifts on resonantly enhanced processes are that the pump laser must be tuned away from the small-field resonance frequency, that the conversion efficiency may saturate, and that the dispersion of the medium may change sign. As an example, the generation of 198-A radiation by a five-photon mixing process in Li(+) is considered.

  12. 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.

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

    PubMed

    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.

  14. 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

  15. 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.

  16. 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

  17. 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)

  18. 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.

  19. 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.

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

    SciTech Connect

    Morgan, C.D.

    1997-05-09

    The objective of this project is to increase oil production and reserves in the Uinta Basin by demonstrating improved completion techniques. Low productivity of Uinta Basin wells is caused by gross production intervals of several thousand feet that contain perforated thief zones, water-bearing zones, and perforated oil-bearing intervals. Geologic and engineering characterization and computer simulation of the Green River and Wasatch Formations in the Bluebell field will determine reservoir heterogeneities related to fractures and depositional trends. This will be followed by drilling and recompletion of several wells to demonstrate improved completion techniques based on the reservoir characterization. Transfer of the project results will be an ongoing component of the project.

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

    SciTech Connect

    Morgan, Craig D.

    1999-11-01

    The objective of this project is to increase oil production and reserves in the Uinta Basin by demonstrating improved completion techniques. Low productivity of Uinta Basin wells is caused by gross production intervals of several thousand feet that contain perforated thief zones, water-bearing zones, and unperforated oil-bearing intervals. Geologic and engineering characterization and computer simulation of the Green River and Wasatch Formations in the Bluebell field will determine reservoir heterogeneities related to fractures and depositional trends. This will be followed by drilling and recompletion of several wells to demonstrate improved completion techniques based on the reservoir characterization. Transfer of the project results will be an ongoing component of the project.

  2. 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.

  3. New experimental technique for the measurement of the velocity field in thin films falling over obstacles

    NASA Astrophysics Data System (ADS)

    Landel, Julien R.; Daglis, Ana; McEvoy, Harry; Dalziel, Stuart B.

    2014-11-01

    We present a new experimental technique to measure the surface velocity of a thin falling film. Thin falling films are important in various processes such as cooling in heat exchangers or cleaning processes. For instance, in a household dishwasher cleaning depends on the ability of a thin draining film to remove material from a substrate. We are interested in the impact of obstacles attached to a substrate on the velocity field of a thin film flowing over them. Measuring the velocity field of thin falling films is a challenging experimental problem due to the small depth of the flow and the large velocity gradient across its depth. We propose a new technique based on PIV to measure the plane components of the velocity at the surface of the film over an arbitrarily large area and an arbitrarily large resolution, depending mostly on the image acquisition technique. We perform experiments with thin films of water flowing on a flat inclined surface, made of glass or stainless steel. The typical Reynolds number of the film is of the order of 100 to 1000, computed using the surface velocity, the film thickness and the kinematic viscosity of the film. We measure the modification to the flow field, from a viscous-gravity regime, caused by small solid obstacles, such as three-dimensional hemispherical obstacles and two-dimensional steps. We compare our results with past theoretical and numerical studies. This material is based upon work supported by the Defense Threat Reduction Agency under Contract No. HDTRA1-12-D-0003-0001.

  4. 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.

  5. A planar near-field scanning technique for bistatic radar cross section measurements

    NASA Technical Reports Server (NTRS)

    Tuhela-Reuning, S.; Walton, E. K.

    1990-01-01

    A progress report on the development of a bistatic radar cross section (RCS) measurement range is presented. A technique using one parabolic reflector and a planar scanning probe antenna is analyzed. The field pattern in the test zone is computed using a spatial array of signal sources. It achieved an illumination pattern with 1 dB amplitude and 15 degree phase ripple over the target zone. The required scan plane size is found to be proportional to the size of the desired test target. Scan plane probe sample spacing can be increased beyond the Nyquist lambda/2 limit permitting constant probe sample spacing over a range of frequencies.

  6. 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.

  7. Background field method: Alternative way of deriving the pinch technique's results

    SciTech Connect

    Hashimoto, S.; Kodaira, J.; Yasui, Y. ); Sasaki, K. )

    1994-12-01

    We show that the background field method (BFM) is a simple way of deriving the same gauge-invariant results which are obtained by the pinch technique (PT). For illustration we construct gauge-invariant self-energy and three-point vertices for gluons at the one-loop level by the BFM and demonstrate that we get the same results which were derived via the PT. We also calculate the four-gluon vertex in the BFM and show that this vertex obeys the same Ward identity that was found with the PT.

  8. Detection and identification of microorganisms using a combined flow field-flow fractionation/spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Fu, Xiaojuan

    This doctoral project is focused on the implementation of a novel micron and sub-micron particle characterization technology for in-situ, continuous monitoring and detecting of microorganisms in water. The particle technology is based on simultaneous characterizing the joint particle property distribution (size, shape, and chemical composition) through the combined fractionation/separation and light scattering detection and interpretation techniques. Over more than a decade, field-flow fractionation (FFF) has shown to be well-suited for the separation and/or selection of bacteria (Giddings, 1993). As the most universal fractionation technique among the FFF family, flow field-flow fractionation (FFFF) has been chosen as the separation device in this research. The multi-angle laser light scattering (MALLS) photometer and the UV-vis/liquid core optical waveguide constitute the primary on-line light scattering detection system. The angular spectra obtained by the MALLS photometer provided information on the shape of microorganism; the multi-wavelength transmission spectra of microorganisms contain quantitative information on their size, number, shape, chemical composition and internal structure, which are essential for identification and classification of microorganisms. Both experimental results and the theoretical prediction have revealed that the particle size resolution capabilities of the FFFF fractionation system coupled with the sensitivity of the laser light scattering to particle shape, and the sensitivity of the UV-vis spectra to cell size, shape, cell orientation and chemical composition offer an integrated system for the identification and classification of microorganisms. The ability to discriminate between cell species was demonstrated by the light scattering and absorption interpretation model, which is based on light scattering theory (Rayleigh-Debye-Gans approximation), spectral deconvolution techniques, and on the approximation of the frequency

  9. Field comparison of disjunct and conventional eddy covariance techniques for trace gas flux measurements.

    PubMed

    Rinne, J; Douffet, T; Prigent, Y; Durand, P

    2008-04-01

    A field intercomparison experiment of the disjunct eddy covariance (DEC) and the conventional eddy covariance (EC) techniques was conducted over a grass field. The half-hourly water vapor fluxes measured by the DEC were within the estimated uncertainty from the fluxes measured by the EC. On the average there was a slight overestimation (<10%) of the fluxes measured by the DEC during the day and underestimation during the night as compared to the fluxes measured by the EC. As this bias does not appear in the simulated DEC measurements it is likely to be due to instrumental problems. The insensitivity of the quality of the fluxes measured by the DEC method to the deficiencies in the gas analysis shows the robustness of this new approach for measuring the surface-atmosphere exchange of trace gases.

  10. New test techniques to evaluate near field effects for supersonic store carriage and separation

    NASA Technical Reports Server (NTRS)

    Sawyer, Wallace C.; Stallings, Robert L., Jr.; Wilcox, Floyd J., Jr.; Blair, A. B., Jr.; Monta, William J.; Plentovich, Elizabeth B.

    1989-01-01

    Store separation and store carriage drag studies were conducted. A primary purpose is to develop new experimental methods to evaluate near field effects of store separation and levels of store carriage drag associated with a variety of carriage techniques for different store shapes and arrangements. Flow field measurements consisting of surface pressure distributions and vapor screen photographs are used to analyze the variations of the store separation characteristics with cavity geometry. Store carriage drag measurements representative of tangent, semi-submerged, and internal carriage installations are presented and discussed. Results are included from both fully metric models and models with only metric segments (metric pallets) and the relative merits of the two are discussed. Carriage drag measurements for store installations on an aircraft parent body are compared both with prediction methods and with installations on a generic parent body.

  11. 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.

  12. 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.

  13. 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.}

  14. Investigation of well redevelopment techniques for the MWD Well Field, Savannah River Site, South Carolina

    SciTech Connect

    Kroening, D.E.; Snipes, D.S.; Falta, R.W.; Benson, S.M. . Dept. of Earth Sciences); Janssen, J. )

    1994-03-01

    Clemson University, in cooperation with the Savannah River Site (SRS) is investigating well treatment techniques at the Mixed Waste Disposal (MWD) Well Field at SRS. This well field consists of fifteen wells screened in three aquifers with a downward trending head gradient. Based on aquifer performance tests of the MWD wells, it has been determined that many of the wells exhibit low well efficiencies and high skin factors, indicative of damaged wells. Bacterial investigations show that the biological activity in these wells is low, probably due to a high pH environment. Evaluation of the Calcite Saturation Index for each well indicates that nearly all of the MWD wells have the potential for precipitating calcite and calcite deposits have been observed on downhole equipment. The calcite deposits may occur due to the dissolution of the grout mixtures by waters infiltrating down the well annulus driven by the downward head gradient with subsequent precipitation of calcite in the higher pH sand pack. Well rehabilitation techniques currently under investigation include acidification, hydraulic fracturing and traditional physical methods. In addition to treating the wells at MWD, the authors plan to perform aquifer performance tests and evaluate post-treatment skin factors. Further research into the long term effects of well treatment will be conducted, focusing on long term chemical changes brought about by the treatments.

  15. 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.

  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. Unsupervised change detection based on improved Markov random field technique using multichannel synthetic aperture radar images

    NASA Astrophysics Data System (ADS)

    Salehi, Sara; Valadan Zoej, Mohammad Javad

    2014-01-01

    Change detection represents an important remote sensing tool in environmental monitoring and disaster management. In this respect, multichannel synthetic aperture radar (SAR) data offer great potential because of their insensitivity to atmospheric and sun-illumination conditions (over optical multispectral data) and the improved discrimination capability they may provide compared to single-channel SAR. The problem of detecting the changes caused by flooding is addressed by a contextual unsupervised technique based on a Markovian data fusion approach. However, the isotropic formulation of Markov random field (MRF) models causes oversmoothing of spatial boundaries in the final change maps. In order to reduce this drawback, an edge-preserving MRF model is proposed and formulated by using energy functions that combine the edge information extracted from the produced edge maps using competitive fuzzy rules and Canny technique, the information conveyed by each SAR channel, and the spatial contextual information. The proposed technique is experimentally validated with semisimulated data and real ASAR-ENVISAT images. Change detection results obtained by the improved MRF model exhibited a higher accuracy than its predecessors for both semisimulated (average 12%) and real (average 6%) data.

  19. 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.

  20. 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

    2016-04-01

    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.

  1. 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.

  2. Magnetic separation technique for environmental water purification by strong magnetic field generator loading HTS bulk magnets

    NASA Astrophysics Data System (ADS)

    Oka, T.; Tanaka, K.; Kimura, T.; Mimura, D.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M.; Yokoyama, K.; Yamaguchi, M.

    2010-11-01

    The magnetic separation technique in combination with high temperature superconducting bulk magnets has been investigated to purify the ground water which has been used in the coolant system for the incinerator furnace to cool the burning gas. The experiment has been operated by means of the newly-built alternating channel type magnetic separating device. The separation ratios of ferromagnetic flocks including fine magnetite powder have been estimated by means of the high gradient magnetic separation method with small iron balls filled in the water channels. As the magnetic force acting on the magnetic particle is given by the product of a magnetization of the material and a gradient of magnetic field, and as the ferromagnetic stainless steel balls yield the steep gradient of magnetic field around them in a strong magnetic field, the system has exhibited a quite excellent performance with respect to the separation ratios. The separation ratios of the flocks which contain the magnetite powder with the values more than 50 ppm have remained over 80% for under the flow rates less than 5 L/min.

  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. Floating field ring technique applied to enhance fill factor of silicon photomultiplier elementary cell

    NASA Astrophysics Data System (ADS)

    Maresca, L.; De Laurentis, M.; Riccio, M.; Irace, A.; Breglio, G.

    2011-06-01

    A silicon photomultiplier (SiPM) is a matrix of Geiger-mode avalanche photodiodes (GM-APDs) connected in parallel. One of the main drawback in the SiPm is the low Photon Detection Efficiency(PDE) also due to the low geometrical fill factor of the microcells array. This paper reports on the analysis and simulation of the single floating field ring technique, applied to the junction termination of the single cell of a Silicon Photomultiplier (SiPm). A floating guard ring is made along the border of the single microcell and it is not connected to the cathodic contact. Even if the ring is not electrically connected to the main junction, it mitigates the variation of the electrical field at the main termination. The effect of the junction-to-ring distance is analytically investigated by using cylindrical coordinates and an optimal distance together with the optimal width is found. Results show that the single floating ring reduces the junction edge electric field by keeping constant the size of the microcell allowing, then, an improvement for the geometrical fill factor. Results are supported by TCAD simulations.

  5. 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.

  6. 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

  7. Evaluation of stereotactic body radiotherapy (SBRT) boost in the management of endometrial cancer.

    PubMed

    Demiral, S; Beyzadeoglu, M; Uysal, B; Oysul, K; Kahya, Y Elcim; Sager, O; Dincoglan, F; Gamsiz, H; Dirican, B; Surenkok, S

    2013-01-01

    The purpose of this study is to evaluate the use of linear accelerator (LINAC)-based stereotactic body radiotherapy (SBRT) boost with multileaf collimator technique after pelvic radiotherapy (RT) in patients with endometrial cancer. Consecutive patients with endometrial cancer treated using LINAC-based SBRT boost after pelvic RT were enrolled in the study. All patients had undergone surgery including total abdominal hysterectomy and bilateral salpingo-oophorectomy ± pelvic/paraortic lymphadenectomy before RT. Prescribed external pelvic RT dose was 45 Gray (Gy) in 1.8 Gy daily fractions. All patients were treated with SBRT boost after pelvic RT. The prescribed SBRT boost dose to the upper two thirds of the vagina including the vaginal vault was 18 Gy delivered in 3 fractions with 1-week intervals. Gastrointestinal and genitourinary toxicity was assessed using the Common Terminology Criteria for Adverse Events version 3 (CTCAE v3).Between April 2010 and May 2011, 18 patients with stage I-III endometrial cancer were treated with LINAC-based SBRT boost after pelvic RT. At a median follow-up of 24 (8-26) months with magnetic resonance imaging (MRI) and gynecological examination, local control rate of the study group was 100 % with negligible acute and late toxicity.LINAC-based SBRT boost to the vaginal cuff is a feasible gynecological cancer treatment modality with excellent local control and minimal toxicity that may replace traditional brachytherapy boost in the management of endometrial cancer. PMID:23374003

  8. Boosting human learning by hypnosis.

    PubMed

    Nemeth, Dezso; Janacsek, Karolina; Polner, Bertalan; Kovacs, Zoltan Ambrus

    2013-04-01

    Human learning and memory depend on multiple cognitive systems related to dissociable brain structures. These systems interact not only in cooperative but also sometimes competitive ways in optimizing performance. Previous studies showed that manipulations reducing the engagement of frontal lobe-mediated explicit attentional processes could lead to improved performance in striatum-related procedural learning. In our study, hypnosis was used as a tool to reduce the competition between these 2 systems. We compared learning in hypnosis and in the alert state and found that hypnosis boosted striatum-dependent sequence learning. Since frontal lobe-dependent processes are primarily affected by hypnosis, this finding could be attributed to the disruption of the explicit attentional processes. Our result sheds light not only on the competitive nature of brain systems in cognitive processes but also could have important implications for training and rehabilitation programs, especially for developing new methods to improve human learning and memory performance.

  9. 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

  10. 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.

  11. Developing a marginal field using new techniques-South Monagas Unit, Venezuela

    SciTech Connect

    Skirvin, T.M.; Sven Hagen, E.; McGee, R.A.; Hinrichs, P.D. ); Medina, P.A. )

    1996-01-01

    In 1992 the Venezuelan national oil company, PDVSA, awarded operating service agreements to foreign oil companies for reactivation of marginal oil fields. The South Monagas Unit contains three oil and gas fields, Uracoa, Bombal, and Tucupita, that were not producing prior to the award of the contract As of October 1995, production from Uraroa had exceeded 20 MBbls/day of heavy oil from 26 vertical and 11 horizontal wells. Initial uncertainties about heavy oil treatment capability, water and gas production, oil flow rates, and ultimate recoverable reserves led to a phased development plan that has incrementally reduced the risk of financial exposure over time. The first phase of development utilized conventional geologic techniques and vertical wells to test treatment facilities, mud and gravel-pack technologies, and flow rates. Positive results led to the next phase of development which focused on reservoir performance and well optimization. A horizontal well drilling program was implemented in December 1993. A milestone in this program was the first gravel-pack horizontal well in Venezuela, completed in February, 1995. A pilot 2-D seismic program in late 1994 confined that high-quality seismic could be acquired to significantly enhance the development of Uracoa. A 175 W 3-D survey was shot and processed in mid-1995. Concurrently, borehole imaging logs were acquired in vertical wells to determine internal reservoir heterogeneity and sand depositional models. The sequence stratigraphic model that evolved, based on outcrop field analogs, 3-D seismic stratigraphy, and regional well control, is being used to optimize field development. In addition, new exploration concepts are being tested without risk using strategically located water injection wells as test wells.

  12. Developing a marginal field using new techniques-South Monagas Unit, Venezuela

    SciTech Connect

    Skirvin, T.M.; Sven Hagen, E.; McGee, R.A.; Hinrichs, P.D.; Medina, P.A.

    1996-12-31

    In 1992 the Venezuelan national oil company, PDVSA, awarded operating service agreements to foreign oil companies for reactivation of marginal oil fields. The South Monagas Unit contains three oil and gas fields, Uracoa, Bombal, and Tucupita, that were not producing prior to the award of the contract As of October 1995, production from Uraroa had exceeded 20 MBbls/day of heavy oil from 26 vertical and 11 horizontal wells. Initial uncertainties about heavy oil treatment capability, water and gas production, oil flow rates, and ultimate recoverable reserves led to a phased development plan that has incrementally reduced the risk of financial exposure over time. The first phase of development utilized conventional geologic techniques and vertical wells to test treatment facilities, mud and gravel-pack technologies, and flow rates. Positive results led to the next phase of development which focused on reservoir performance and well optimization. A horizontal well drilling program was implemented in December 1993. A milestone in this program was the first gravel-pack horizontal well in Venezuela, completed in February, 1995. A pilot 2-D seismic program in late 1994 confined that high-quality seismic could be acquired to significantly enhance the development of Uracoa. A 175 W 3-D survey was shot and processed in mid-1995. Concurrently, borehole imaging logs were acquired in vertical wells to determine internal reservoir heterogeneity and sand depositional models. The sequence stratigraphic model that evolved, based on outcrop field analogs, 3-D seismic stratigraphy, and regional well control, is being used to optimize field development. In addition, new exploration concepts are being tested without risk using strategically located water injection wells as test wells.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Development of algorithms for capacitance imaging techniques for fluidized bed flow fields. 1990 Annual report

    SciTech Connect

    Loudin, W.J.

    1991-01-01

    The objective of this research is to provide support for the instrumentation concept of a High Resolution Capacitance Imaging System (HRCIS). The work involves the development and evaluation of the mathematical theory and associated models and algorithms which reduce the electronic measurements to valid physical characterizations. The research and development require the investigation of techniques to solve large systems of equations based on capacitance measurements for various electrode configurations in order to estimate densities of materials in a cross-section of a fluidized bed. Capacitance measurements are made for 400 connections of the 32-electrode system; 400 corresponding electric-field curves are constructed by solving a second order partial differential equation. These curves are used to partition the circular disk into 193 regions called pixels, and the density of material in each pixel is to be estimated. Two methods of approximating densities have been developed and consideration of a third method has been initiated. One method (Method 1) is based on products of displacement currents for intersecting electric-field curves on a cross section. For each pixel one point of intersection is chosen, and the product of the capacitance measurements is found. Both the product and the square-root-of-product seem to yield good relative distribution of densities.

  18. Development of algorithms for capacitance imaging techniques for fluidized bed flow fields

    SciTech Connect

    Loudin, W.J.

    1991-01-01

    The objective of this research is to provide support for the instrumentation concept of a High Resolution Capacitance Imaging System (HRCIS). The work involves the development and evaluation of the mathematical theory and associated models and algorithms which reduce the electronic measurements to valid physical characterizations. The research and development require the investigation of techniques to solve large systems of equations based on capacitance measurements for various electrode configurations in order to estimate densities of materials in a cross-section of a fluidized bed. Capacitance measurements are made for 400 connections of the 32-electrode system; 400 corresponding electric-field curves are constructed by solving a second order partial differential equation. These curves are used to partition the circular disk into 193 regions called pixels, and the density of material in each pixel is to be estimated. Two methods of approximating densities have been developed and consideration of a third method has been initiated. One method (Method 1) is based on products of displacement currents for intersecting electric-field curves on a cross section. For each pixel one point of intersection is chosen, and the product of the capacitance measurements is found. Both the product and the square-root-of-product seem to yield good relative distribution of densities.

  19. 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.

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. Riemann curvature of a boosted spacetime geometry

    NASA Astrophysics Data System (ADS)

    Battista, Emmanuele; Esposito, Giampiero; Scudellaro, Paolo; Tramontano, Francesco

    2016-10-01

    The ultrarelativistic boosting procedure had been applied in the literature to map the metric of Schwarzschild-de Sitter spacetime into a metric describing de Sitter spacetime plus a shock-wave singularity located on a null hypersurface. This paper evaluates the Riemann curvature tensor of the boosted Schwarzschild-de Sitter metric by means of numerical calculations, which make it possible to reach the ultrarelativistic regime gradually by letting the boost velocity approach the speed of light. Thus, for the first time in the literature, the singular limit of curvature, through Dirac’s δ distribution and its derivatives, is numerically evaluated for this class of spacetimes. Moreover, the analysis of the Kretschmann invariant and the geodesic equation shows that the spacetime possesses a “scalar curvature singularity” within a 3-sphere and it is possible to define what we here call “boosted horizon”, a sort of elastic wall where all particles are surprisingly pushed away, as numerical analysis demonstrates. This seems to suggest that such “boosted geometries” are ruled by a sort of “antigravity effect” since all geodesics seem to refuse to enter the “boosted horizon” and are “reflected” by it, even though their initial conditions are aimed at driving the particles toward the “boosted horizon” itself. Eventually, the equivalence with the coordinate shift method is invoked in order to demonstrate that all δ2 terms appearing in the Riemann curvature tensor give vanishing contribution in distributional sense.

  7. Influence of magnetic fields on calcium salts crystal formation: an explanation of the 'pulsed electromagnetic field' technique for bone healing.

    PubMed

    Madroñero, A

    1990-09-01

    In the search for a mechanism by means of which a magnetic field deparalyses non-unions and enhances bone tissue formation, the influence of continuous magnetic fields on the formation of calcium phosphate crystal seeds has been investigated. From this perspective, an explanation is given of a working mode in conventional equipment for pulsed electromagnetic field treatment; this is compared with multifunction equipment.

  8. Mapping Tamarix: New techniques for field measurements, spatial modeling and remote sensing

    NASA Astrophysics Data System (ADS)

    Evangelista, Paul H.

    Native riparian ecosystems throughout the southwestern United States are being altered by the rapid invasion of Tamarix species, commonly known as tamarisk. The effects that tamarisk has on ecosystem processes have been poorly quantified largely due to inadequate survey methods. I tested new approaches for field measurements, spatial models and remote sensing to improve our ability measure and to map tamarisk occurrence, and provide new methods that will assist in management and control efforts. Examining allometric relationships between basal cover and height measurements collected in the field, I was able to produce several models to accurately estimate aboveground biomass. The best two models were explained 97% of the variance (R 2 = 0.97). Next, I tested five commonly used predictive spatial models to identify which methods performed best for tamarisk using different types of data collected in the field. Most spatial models performed well for tamarisk, with logistic regression performing best with an Area Under the receiver-operating characteristic Curve (AUC) of 0.89 and overall accuracy of 85%. The results of this study also suggested that models may not perform equally with different invasive species, and that results may be influenced by species traits and their interaction with environmental factors. Lastly, I tested several approaches to improve the ability to remotely sense tamarisk occurrence. Using Landsat7 ETM+ satellite scenes and derived vegetation indices for six different months of the growing season, I examined their ability to detect tamarisk individually (single-scene analyses) and collectively (time-series). My results showed that time-series analyses were best suited to distinguish tamarisk from other vegetation and landscape features (AUC = 0.96, overall accuracy = 90%). June, August and September were the best months to detect unique phenological attributes that are likely related to the species' extended growing season and green-up during

  9. An Analytical Technique to Elucidate Field Impurities From Manufacturing Uncertainties of an Double Pancake Type HTS Insert for High Field LTS/HTS NMR Magnets

    PubMed Central

    Hahn, Seung-yong; Ahn, Min Cheol; Bobrov, Emanuel Saul; Bascuñán, Juan; Iwasa, Yukikazu

    2010-01-01

    This paper addresses adverse effects of dimensional uncertainties of an HTS insert assembled with double-pancake coils on spatial field homogeneity. Each DP coil was wound with Bi2223 tapes having dimensional tolerances larger than one order of magnitude of those accepted for LTS wires used in conventional NMR magnets. The paper presents: 1) dimensional variations measured in two LTS/HTS NMR magnets, 350 MHz (LH350) and 700 MHz (LH700), both built and operated at the Francis Bitter Magnet Laboratory; and 2) an analytical technique and its application to elucidate the field impurities measured with the two LTS/HTS magnets. Field impurities computed with the analytical model and those measured with the two LTS/HTS magnets agree quite well, demonstrating that this analytical technique is applicable to design a DP-assembled HTS insert with an improved field homogeneity for a high-field LTS/HTS NMR magnet. PMID:20407595

  10. An Analytical Technique to Elucidate Field Impurities From Manufacturing Uncertainties of an Double Pancake Type HTS Insert for High Field LTS/HTS NMR Magnets.

    PubMed

    Hahn, Seung-Yong; Ahn, Min Cheol; Bobrov, Emanuel Saul; Bascuñán, Juan; Iwasa, Yukikazu

    2009-06-01

    This paper addresses adverse effects of dimensional uncertainties of an HTS insert assembled with double-pancake coils on spatial field homogeneity. Each DP coil was wound with Bi2223 tapes having dimensional tolerances larger than one order of magnitude of those accepted for LTS wires used in conventional NMR magnets. The paper presents: 1) dimensional variations measured in two LTS/HTS NMR magnets, 350 MHz (LH350) and 700 MHz (LH700), both built and operated at the Francis Bitter Magnet Laboratory; and 2) an analytical technique and its application to elucidate the field impurities measured with the two LTS/HTS magnets. Field impurities computed with the analytical model and those measured with the two LTS/HTS magnets agree quite well, demonstrating that this analytical technique is applicable to design a DP-assembled HTS insert with an improved field homogeneity for a high-field LTS/HTS NMR magnet.

  11. 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

  12. Boosting domain wall propagation by notches

    NASA Astrophysics Data System (ADS)

    Yuan, H. Y.; Wang, X. R.

    2015-08-01

    We report a counterintuitive finding that notches in an otherwise homogeneous magnetic nanowire can boost current-induced domain wall (DW) propagation. DW motion in notch-modulated wires can be classified into three phases: (1) A DW is pinned around a notch when the current density is below the depinning current density. (2) DW propagation velocity is boosted by notches above the depinning current density and when nonadiabatic spin-transfer torque strength β is smaller than the Gilbert damping constant α . The boost can be multifold. (3) DW propagation velocity is hindered when β >α . The results are explained by using the Thiele equation.

  13. Computed-tomographic density measurement of supersonic flow field by colored-grid background oriented schlieren (CGBOS) technique

    NASA Astrophysics Data System (ADS)

    Ota, Masanori; Hamada, Kenta; Kato, Hiroko; Maeno, Kazuo

    2011-10-01

    The background oriented schlieren (BOS) technique is one of the visualization techniques that enable the quantitative measurement of density information in the flow field with very simple experimental setup. The principle of BOS is similar to the conventional schlieren technique, which exploits the bending of light caused by refractive index change corresponding to density change in the medium and both techniques are sensible to density gradient. In this report we propose colored-grid background oriented schlieren (CGBOS) technique. The experiments were carried out in a supersonic wind tunnel of test section size 0.6 × 0.6 m2 at JAXA-ISAS. A colored-grid pattern was used as background image and density gradient in vertical and horizontal direction was obtained. Computed tomographic reconstructions of 3D density information of the supersonic flow field around an asymmetric body from multi-directional CGBOS images were examined.

  14. 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.

  15. 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

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

    PubMed

    Parr, Andreas; Miesen, Robert; Vossiek, Martin

    2016-06-25

    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.

  17. 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

  18. Skip Dinner and Maybe Boost Your Metabolism

    MedlinePlus

    ... 161845.html Skip Dinner and Maybe Boost Your Metabolism But, study didn't show overall changes in ... has an internal clock, and many aspects of metabolism are working best in the morning, according to ...

  19. 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, ...

  20. 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 ...

  1. 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.

  2. 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).

  3. 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).

  4. 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 ...

  5. Series-Connected Buck Boost Regulators

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur G.

    2005-01-01

    processed. In the SCBBR, the unswitched majority of the power is passed through with very little power loss, and little if any increase in the sizes of the converter components is needed to enable the components to handle the unswitched power. As a result, the power-conversion efficiency of the regulator can be very high, as shown in the example of Figure 1. A basic SCBBR includes a DC-to-DC converter (see Figure 2). The switches and primary winding of a transformer in the converter is connected across the input bus, while the secondary winding and switches are connected in series with the output bus, so that the output voltage is the sum of the input voltage and the secondary voltage of the converter. In the breadboard SCBBR, the input voltage applied to the primary winding is switched by use of metal oxide/semiconductor field-effect transistors (MOSFETs) in a full bridge circuit; the secondary winding is center-tapped, with two MOSFET switches and diode rectifiers connected in opposed series in each leg. The sets of opposed switches and rectifiers are what enable operation in either a boost or a buck mode. In the boost mode, input voltage and current, and the output voltage and current are all positive; that is, the secondary voltage is added to the input voltage and the net output voltage can be regulated at a value equal or greater than the input voltage. In the buck mode, input voltage is still positive and the current still flows in the same direction in the secondary, but the switches are controlled such that some power flows from the secondary to the primary. The voltage across the secondary and the current into the primary are reversed. The result is that the output voltage is lower than the input voltage, and some power is recirculated from the converter secondary back to the input. Quantitatively, the advantage of an SCBBR is a direct function of the regulation range required. If, for example, a regulation range of 20 percent is required for a 500-W supply, th it

  6. 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}.

  7. 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.

  8. 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

  9. Field-based DGTD/PIC technique for general and stable simulation of interaction between light and electron bunches

    NASA Astrophysics Data System (ADS)

    Fallahi, Arya; Kärtner, Franz

    2014-12-01

    We introduce a hybrid technique based on the discontinuous Galerkin time domain (DGTD) and the particle in cell (PIC) simulation methods for the analysis of interaction between light and charged particles. The DGTD algorithm is a three-dimensional, dual-field and fully explicit method for efficiently solving Maxwell equations in the time domain on unstructured grids. On the other hand, the PIC algorithm is a versatile technique for the simulation of charged particles in an electromagnetic field. This paper introduces a novel strategy for combining both methods to solve for the electron motion and field distribution when an optical beam interacts with an electron bunch in a very general geometry. The developed software offers a complete and stable numerical solution of the problem for arbitrary charge and field distributions in the time domain on unstructured grids. For this purpose, an advanced search algorithm is developed for fast calculation of field data at charge points and for later importing to the PIC simulations. In addition, we propose a field-based coupling between the two methods resulting in a stable and precise time marching scheme for both fields and charged particle motion. To benchmark the solver, some examples are numerically solved and compared with analytical solutions. Eventually, the developed software is utilized to simulate the field emission from a flat metal plate and a silicon nano-tip. In the future, we will use this technique for the simulation and design of ultrafast compact x-ray sources.

  10. 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

  11. Dose Distribution Analysis of Axillary Lymph Nodes for Three-Dimensional Conformal Radiotherapy With a Field-in-Field Technique for Breast Cancer

    SciTech Connect

    Ohashi, Toshio Takeda, Atsuya; Shigematsu, Naoyuki; Fukada, Junichi; Sanuki, Naoko; Amemiya, Atsushi; Kubo, Atsushi

    2009-01-01

    Purpose: We previously reported that most of axillary regions could be irradiated by the modified tangential irradiation technique (MTIT). The purpose of this study was to determine whether the three-dimensional conformal radiotherapy (3D-CRT) with a field-in-field technique improves dosimetry for the breast and axillary nodes. Methods and Materials: Fifty patients with left-sided breast cancer were enrolled. With MTIT, we planned the radiation field to be wider in the cranial direction than the standard tangential fields to include the axillary regions. With 3D-CRT, a field-in-field technique was used to spare the heart and contralateral breast to the extent possible by applying the multileaf collimator manually. Dose-volume histograms were compared for the breast, axillary region, heart, lung, and other normal tissues. Results: There were no significant differences in the percent volume of the breast receiving >90% of the prescribed dose (V90) between MTIT and 3D-CRT. The mean V90 of the level I to III axillary regions were increased from 93.7%, 48.2%, and 41.3% with MTIT to 97.6%, 85.8%, and 82.8% with 3D-CRT. 3D-CRT significantly reduced the volume of the heart receiving >30 Gy (mean, 7.6 vs. 15.9 mL), the percent volume of the bilateral lung receiving >20 Gy (7.4% vs. 8.9%), and the volume of other normal tissues receiving >107% of the prescribed dose (0.1 vs. 2.9 mL). Conclusion: The use of 3D-CRT with a field-in-field technique improves axillary node coverage, while decreasing doses to the heart, lungs, and the other normal tissues, compared with MTIT.

  12. Diamond Field Emission Source using Transfer Mold Technique Prepared by Diamond Powder Seeding

    NASA Astrophysics Data System (ADS)

    Tezuka, Sachiaki; Matsuba, Yohei; Takahashi, Kohro

    Diamond thin films fabricated by MPCVD (microwave plasma chemical vapor deposition) are available for use as a field emitter material, because of its high mechanical quality, thermal conductivity, chemical stability, environmental tolerance, and NEA (negative electron affinity). Diode and triode emitter arrays using P-doped polycrystalline diamond were manufactured on a SiO2/Si(100) substrate with reverse pyramids formed by the transfer mold technique. As the diamond nucleation process, spin-coat seeding with pure diamond powder dispersed in isoamyl acetate has been introduced in place of the bias method. SEM (scanning electron microscopy) images and Raman spectroscopy indicate that the crystal quality of the diamond thin film fabricated by spin-coat seeding is superior to that fabricated by the bias method. The diamond crystal completely grew on top of the diode emitter by the US (ultrasonic) treatment in a diamond powder solution before spin-coat seeding. The tip radius was smaller than 50 nm. The beginning voltage of the emission of the diode emitter is 3 V after the DC glow discharge treatment in H2, which is lower than that of an emitter array fabricated by the bias method, 40 V. On the other hand, the emission of the diamond triode emitter starts at a gate voltage of only 0.5 V, and the emission current of 50∼60 mA is obtained at a gate voltage of 2 V.

  13. 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.

  14. Phase field simulation of precipitation in a Mg-Al alloy using two techniques of approximation

    NASA Astrophysics Data System (ADS)

    Han, G. M.; Han, Z. Q.; Luo, A. A.; Sachdev, A. K.; Liu, B. C.

    2012-07-01

    In this paper, the precipitation of β-Mg17Al12 in aging process of Mg-9%Al (mass fraction) alloy was studied using a diffuse-interface phase field model. In the model, the precipitate phase and the matrix are distinguished by a structural order parameter, and the interface region is assumed to be a mixture of the precipitate phase and the matrix. The mixture composition was calculated using a weighted average method. Two techniques of approximation for the chemical free energy of precipitate phase and matrix were employed, where the variation characteristics of the free energy with the mole fraction of solute were included. In the simulation, the temperature and diffusion mobility coefficient were assumed to be constant. The effects of the solution approximations on the morphology evolution and growth kinetics of the precipitate were discussed. The effects of the interface mobility coefficient on the interface growth kinetics were examined, and the effects of the interface anisotropy between the precipitate phase and the matrix on the morphology of the precipitate were also discussed. It is demonstrated that the solution approximation taking into account the interaction between atoms for a binary system provides a good description for the chemical free energy. The simulation results showed that the precipitate phase growing from a supersaturated solid solution has a plate-like shape, which is in agreement with experimental observations. The growth kinetics of the precipitate phase is significantly influenced by the interface mobility coefficient.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. CRT combined with a sequential VMAT boost in the treatment of upper thoracic esophageal cancer.

    PubMed

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

    2013-09-06

    The purpose of this study is to investigate the potential benefits of conformal radiotherapy (CRT) combined with a sequential volumetric-modulated arc therapy (VMAT) boost in the treatment of upper thoracic esophageal cancer. Ten patients with upper thoracic esophageal cancer previously treated with CRT plus a sequential VMAT boost plan were replanned with CRT plus an off-cord CRT boost plan and a full course of VMAT plan. Dosimetric parameters were compared. Results indicated that CRT plus off-cord CRT boost was inferior in planning target volume (PTV) coverage, as indicated by the volume covered by 93% (p = 0.05) and 95% (p = 0.02) of the prescription dose. The full course VMAT plan was superior in conformal index (CI) and conformation number (CN), and produced the highest protection for the spinal cord. CRT plus a VMAT boost demonstrated significant advantages in decreasing the volume of the lung irradiated by a dose of 10 Gy (V10, p = 0.007), 13 Gy (V13, p = 0.003), and 20 Gy (V20, p = 0.001). The full course VMAT plan demonstrated the lowest volume of lung receiving a dose of 30 Gy. CRT plus a VMAT boost for upper thoracic esophageal cancer can improve the target coverage and reduce the volume of lung irradiated by an intermediate dose. This combination may be a promising treatment technique for patients with upper thoracic esophageal cancer.

  20. Magnetic moment measurement in 72Zn using the Transient Field technique and Coulomb excitation in inverse kinematics

    NASA Astrophysics Data System (ADS)

    Illana Sisón, A.; Jungclaus, A.; Orlandi, R.; Perea, A.; Briz, J. A.; Bauer, C.; Gernhäuser, R.; Leske, J.; Mücher, D.; Pakarinen, J.; Pietralla, N.; Rajabali, M. M.; Seiler, D.; Stahl, C.

    2014-03-01

    The g factor of the first excited 2+ state of 72Zn has been measured using the Low Velocity Transient Field (LVTF) technique in combination with Coulomb excitation in inverse kinematics. The aim of the experiment was to test the viability of this method when applied to short-lived radioactive ISOL beams, in particular in comparison to the alternative High Velocity Transient Field (HVTF) technique using fragment beams. The result obtained for g(2+) in 72Zn in the present experiment follows the trend observed for the lighter stables Zn isotopes.

  1. 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.

  2. 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

  3. 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.

  4. A new technique for decoupling the host and nuclear spectra of type I AGNs using integral field spectroscopy

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; García-Lorenzo, B.; Jahnke, K.; Mediavilla, E.; González-Serrano, J. I.; Christensen, L.; Wisotzki, L.

    2006-03-01

    We have developed a new technique to decouple the spectra of the host and the nucleus of type I AGNs using integral field spectroscopy (IFS) data. The technique is a simple extension of methods widely tested in 2D imaging. We present here the results from applying the technique to data taken with INTEGRAL at the 4.2m WHT telescope on the Seyfert 1 radio-galaxy 3C 120. We obtained, for the first time, a clean spectra of the host galaxy, without contamination from the nuclear source.

  5. 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.

  6. 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.

  7. 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}.

  8. 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

  9. Dosimetric comparison of split field and fixed jaw techniques for large IMRT target volumes in the head and neck.

    PubMed

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

    2011-01-01

    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.

  10. 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.

  11. Visual tracking by separability-maximum boosting

    NASA Astrophysics Data System (ADS)

    Hou, Jie; Mao, Yao-bin; Sun, Jin-sheng

    2013-10-01

    Recently, visual tracking has been formulated as a classification problem whose task is to detect the object from the scene with a binary classifier. Boosting based online feature selection methods, which adopt the classifier to appearance changes by choosing the most discriminative features, have been demonstrated to be effective for visual tracking. A major problem of such online feature selection methods is that an inaccurate classifier may give imprecise tracking windows. Tracking error accumulates when the tracker trains the classifier with misaligned samples and finally leads to drifting. Separability-maximum boosting (SMBoost), an alternative form of AdaBoost which characterizes the separability between the object and the scene by their means and covariance matrices, is proposed. SMBoost only needs the means and covariance matrices during training and can be easily adopted to online learning problems by estimating the statistics incrementally. Experiment on UCI machine learning datasets shows that SMBoost is as accurate as offline AdaBoost, and significantly outperforms Oza's online boosting. Accurate classifier stabilizes the tracker on challenging video sequences. Empirical results also demonstrate improvements in term of tracking precision and speed, comparing ours to those state-of-the-art ones.

  12. 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

  13. 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…

  14. Our intraoperative boost radiotherapy experience and applications

    PubMed Central

    Günay, Semra; Alan, Ömür; Yalçın, Orhan; Türkmen, Aygen; Dizdar, Nihal

    2016-01-01

    Objective: To present our experience since November 2013, and case selection criteria for intraoperative boost radiotherapy (IObRT) that significantly reduces the local recurrence rate after breast conserving surgery in patients with breast cancer. Material and Methods: Patients who were suitable for IObRT were identified within the group of patients who were selected for breast conserving surgery at our breast council. A MOBETRON (mobile linear accelerator for IObRT) was used for IObRt during surgery. Results: Patients younger than 60 years old with <3 cm invasive ductal cancer in one focus (or two foci within 2 cm), with a histologic grade of 2–3, and a high possibility of local recurrence were admitted for IObRT application. Informed consent was obtained from all participants. Lumpectomy and sentinel lymph node biopsy was performed and advancement flaps were prepared according to the size and inclination of the conus following evaluation of tumor size and surgical margins by pathology. Distance to the thoracic wall was measured, and a radiation oncologist and radiation physicist calculated the required dose. Anesthesia was regulated with slower ventilation frequency, without causing hypoxia. The skin and incision edges were protected, the field was radiated (with 6 MeV electron beam of 10 Gy) and the incision was closed. In our cases, there were no major postoperative surgical or early radiotherapy related complications. Conclusion: The completion of another stage of local therapy with IObRT during surgery positively effects sequencing of other treatments like chemotherapy, hormonotherapy and radiotherapy, if required. IObRT increases disease free and overall survival, as well as quality of life in breast cancer patients. PMID:26985156

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. Overview of label-free far field optical nanoscopy techniques for nanometrology

    NASA Astrophysics Data System (ADS)

    Montgomery, Paul; Leong-Hoï, Audrey; Anstotz, Freddy; Liu, Hui; Simon, Bertrand; Debailleul, Matthieu; Haeberlé, Olivier

    2016-04-01

    The development of new nanomaterials, devices and systems is very much dependent on the availability of new techniques for nanometrology. There now exists many advanced optical imaging techniques capable of subwavelength resolution and detection, recently brought to the forefront through the 2014 Nobel Prize for chemistry for fluorescent STED and single molecule microscopy. Label-free nanoscopy techniques are particularly interesting for nanometrology since they have the advantages of being less intrusive and open to a wider number of structures that can be observed compared with fluorescent techniques. In view of the existence of many nanoscopy techniques, we present a practical classification scheme to help in their understanding. An important distinction is made between superresolution techniques that provide resolutions better than the classical λ/2 limit of diffraction and nanodetection techniques that are used to detect or characterize unresolved nanostructures or as nanoprobes to image sub-diffraction nanostructures. We then highlight some of the more important label-free techniques that can be used for nanometrology. Superresolution techniques displaying sub-100 nm resolution are demonstrated with tomographic diffractive microscopy (TDM) and submerged microsphere optical nanoscopy (SMON). Nanodetection techniques are separated into three categories depending on whether they use contrast, phase or deconvolution. The use of increased contrast is illustrated with ellipsometric contrast microscopy (SEEC) for measuring nanostructures. Very high sensitivity phase measurement using interference microscopy is then shown for characterizing nanometric surface roughness or internal structures. Finally, the use of through-focus scanning optical microscopy (TSOM) demonstrates the measurement and characterization of 60 nm linewidths in microelectronic devices.

  20. 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.

  1. Boosted Decision Trees and Applications

    NASA Astrophysics Data System (ADS)

    Coadou, Yann

    2013-07-01

    Decision trees are a machine learning technique more and more commonly used in high energy physics, while it has been widely used in the social sciences. After introducing the concepts of decision trees, this article focuses on its application in particle physics.

  2. 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.…

  3. 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).

  4. 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

  5. Magnetic field sensor using the fiber loop ring-down technique and an etched fiber coated with magnetic fluid.

    PubMed

    Shen, Tao; Feng, Yue; Sun, Binchao; Wei, Xinlao

    2016-02-01

    The fiber loop ring-down spectroscopy technique is introduced into the evanescent-field-based sensing scheme in order to create a new type of fiber-based magnetic field sensor. As a consequence, the sensitivity and stability of the magnetic field sensing system are significantly enhanced. The sensor head is constructed using a section of a single-mode fiber with its cladding partially etched. The process of fiber etching is described in detail, and the relationship between the diameter of the etched fiber and the etching time is experimentally investigated. After adopting the appropriate size of the etched fiber, the final experimental results show that the magnetic field strength has a well-defined linear relationship with the inverse of the ring-down time τ over a range of 30 mT with a sensitivity of 95.5 ns/mT.

  6. Magnetic field sensor using the fiber loop ring-down technique and an etched fiber coated with magnetic fluid.

    PubMed

    Shen, Tao; Feng, Yue; Sun, Binchao; Wei, Xinlao

    2016-02-01

    The fiber loop ring-down spectroscopy technique is introduced into the evanescent-field-based sensing scheme in order to create a new type of fiber-based magnetic field sensor. As a consequence, the sensitivity and stability of the magnetic field sensing system are significantly enhanced. The sensor head is constructed using a section of a single-mode fiber with its cladding partially etched. The process of fiber etching is described in detail, and the relationship between the diameter of the etched fiber and the etching time is experimentally investigated. After adopting the appropriate size of the etched fiber, the final experimental results show that the magnetic field strength has a well-defined linear relationship with the inverse of the ring-down time τ over a range of 30 mT with a sensitivity of 95.5 ns/mT. PMID:26836067

  7. 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

  8. Optical phase distortion due to turbulent-fluid density fields - Quantification using the small-aperture beam technique

    NASA Astrophysics Data System (ADS)

    Jumper, E. J.; Hugo, R. J.

    1992-07-01

    This paper discusses the small-aperture beam technique, a relatively new way of experimentally quantifying optically-active, turbulent-fluid-flow-induced optical degradation. The paper lays out the theoretical basis for the technique, and the relationship of the measured jitter of the beam to optical path difference. A numerical simulation of a two-dimensional heated jet is used to explore the validity of beam jitter to obtain optical path difference in a flow region where eddy production constitutes the major character of the 'turbulent' flow field.

  9. 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…

  10. 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…

  11. 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.

  12. A generating technique for Einstein gravity conformally coupled to a scalar field with Higgs potential.

    NASA Astrophysics Data System (ADS)

    Gal'Tsov, D. V.; Xanthopoulos, B. C.

    1992-01-01

    Starting from any solution of the Einstein equations, with cosmological term, coupled to a minimally coupled massless scalar field, a solution of the Einstein equations is constructed, conformally coupled to a massless self-interacting scalar field with the usual Higgs potential. When the cosmological constant vanishes, the Higgs term disappears and the transformation procedure reduces to that obtained by Bekenstein in 1974. As an example, a nonsingular cosmological solution is constructed that describes the restoration of spontaneously broken symmetry.

  13. 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.

  14. Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects.

    PubMed

    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

  15. Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects.

    PubMed

    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.

  16. 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

  17. 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.

  18. Discussion of "the evolution of boosting algorithms" and "extending statistical boosting".

    PubMed

    Bühlmann, P; Gertheiss, J; Hieke, S; Kneib, T; Ma, S; Schumacher, M; Tutz, G; Wang, C-Y; Wang, Z; Ziegler, A

    2014-01-01

    This article is part of a For-Discussion-Section of Methods of Information in Medicine about the papers "The Evolution of Boosting Algorithms - From Machine Learning to Statistical Modelling" and "Extending Statistical Boosting - An Overview of Recent Methodological Developments", written by Andreas Mayr and co-authors. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the Mayr et al. papers. In subsequent issues the discussion can continue through letters to the editor.

  19. 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

  20. Slice-mapping: Reservoir characterization technique - West Yucca Butte Field, Pecos County, Texas

    SciTech Connect

    Casavant, R.R.

    1988-01-01

    The West Yucca Butte field, located in Pecos County, Texas, is a structural-stratigraphic field that lies within the geologic province known as the Sheffield Channel-Val Verde basin area of west Texas. It is one of several producing fields situated in an en echelon pattern along several major northwest-southeast-trending fault systems. These fields are anticlinal features producing gas, condensate, and high-gravity oils from Lower Ordovician dolomites and sandstones, Devonian cherts and cherty limestones, and Pennsylvanian-Permian limestones. Production in the West Yucca Butte field is from the Lower Ordovician Ellenburger Group and the Pennsylvanian Strawn, Canyon, and Cisco Groups. In general, wells located highest on the structure, with adequate porosity, are the better wells. Production is also obtained from downdip wells where reservoirs stratigraphically pinch out along the flanks of the structure. However, in all reservoirs, internal stratigraphic heterogeneities significantly complicated development strategies. The Pennsylvanian reservoirs are very heterogeneous. The carbonates have undergone considerable diagenesis, resulting in the occlusion of primary porosities. Secondary spicular-moldic and microvuggy brecciated porosities are the principal porosity types. Petrographic studies were useful in describing the physical properties of this massive carbonate section and the depositional and diagenetic implications; however, little was known about the distribution and quality of the reservoirs.

  1. Boosted Fast Flux Loop Final Report

    SciTech Connect

    Boosted Fast Flux Loop Project Staff

    2009-09-01

    The Boosted Fast Flux Loop (BFFL) project was initiated to determine basic feasibility of designing, constructing, and installing in a host irradiation facility, an experimental vehicle that can replicate with reasonable fidelity the fast-flux test environment needed for fuels and materials irradiation testing for advanced reactor concepts. Originally called the Gas Test Loop (GTL) project, the activity included (1) determination of requirements that must be met for the GTL to be responsive to potential users, (2) a survey of nuclear facilities that may successfully host the GTL, (3) conceptualizing designs for hardware that can support the needed environments for neutron flux intensity and energy spectrum, atmosphere, flow, etc. needed by the experimenters, and (4) examining other aspects of such a system, such as waste generation and disposal, environmental concerns, needs for additional infrastructure, and requirements for interfacing with the host facility. A revised project plan included requesting an interim decision, termed CD-1A, that had objectives of' establishing the site for the project at the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL), deferring the CD 1 application, and authorizing a research program that would resolve the most pressing technical questions regarding GTL feasibility, including issues relating to the use of booster fuel in the ATR. Major research tasks were (1) hydraulic testing to establish flow conditions through the booster fuel, (2) mini-plate irradiation tests and post-irradiation examination to alleviate concerns over corrosion at the high heat fluxes planned, (3) development and demonstration of booster fuel fabrication techniques, and (4) a review of the impact of the GTL on the ATR safety basis. A revised cooling concept for the apparatus was conceptualized, which resulted in renaming the project to the BFFL. Before the subsequent CD-1 approval request could be made, a decision was made in April 2006

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. A comparison of "flat fielding" techniques for x-ray framing cameras

    NASA Astrophysics Data System (ADS)

    Benedetti, L. R.; Trosseille, C.; Holder, J. P.; Piston, K.; Hargrove, D.; Bradley, D. K.; Bell, P.; Raimbourg, J.; Prat, M.; Pickworth, L. A.; Khan, S. F.

    2016-11-01

    Gain can vary across the active area of an x-ray framing camera by a factor of 4 (or more!) due to the voltage loss and dispersion associated with pulse transmission in a microstripline-coated microchannel plate. In order to make quantitative measurements, it is consequently important to measure the gain variation ("flat field"). Moreover, because of electromagnetic cross talk, gain variation depends on specific operational parameters, and ideally a flat field would be obtained at all operating conditions. As part of a collaboration between Lawrence Livermore National Laboratory's National Ignition Facility and the Commissariat à l'Énergie Atomique, we have been able to evaluate the consistency of three different methods of measuring x-ray flat fields. By applying all three methods to a single camera, we are able to isolate performance from method. Here we report the consistency of the methods and discuss systematic issues with the implementation and analysis of each.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Arbitrary magnetic field gradient waveform correction using an impulse response based pre-equalization technique.

    PubMed

    Goora, Frédéric G; Colpitts, Bruce G; Balcom, Bruce J

    2014-01-01

    The time-varying magnetic fields used in magnetic resonance applications result in the induction of eddy currents on conductive structures in the vicinity of both the sample under investigation and the gradient coils. These eddy currents typically result in undesired degradations of image quality for MRI applications. Their ubiquitous nature has resulted in the development of various approaches to characterize and minimize their impact on image quality. This paper outlines a method that utilizes the magnetic field gradient waveform monitor method to directly measure the temporal evolution of the magnetic field gradient from a step-like input function and extracts the system impulse response. With the basic assumption that the gradient system is sufficiently linear and time invariant to permit system theory analysis, the impulse response is used to determine a pre-equalized (optimized) input waveform that provides a desired gradient response at the output of the system. An algorithm has been developed that calculates a pre-equalized waveform that may be accurately reproduced by the amplifier (is physically realizable) and accounts for system limitations including system bandwidth, amplifier slew rate capabilities, and noise inherent in the initial measurement. Significant improvements in magnetic field gradient waveform fidelity after pre-equalization have been realized and are summarized. PMID:24316188

  19. Effect of Field Independence/Dependence on Two Textbook Notetaking Techniques.

    ERIC Educational Resources Information Center

    Lipsky, Sally A.

    This study was performed to assess the effect of field independence/dependence on the successful use of mapping or outlining to take notes from textbooks. Success was measured in terms of student performance on a comprehension test and thoroughness of notetaking. The study sample of 38 students enrolled in reading and study skills courses at a…

  20. 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...

  1. 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...

  2. Arbitrary magnetic field gradient waveform correction using an impulse response based pre-equalization technique.

    PubMed

    Goora, Frédéric G; Colpitts, Bruce G; Balcom, Bruce J

    2014-01-01

    The time-varying magnetic fields used in magnetic resonance applications result in the induction of eddy currents on conductive structures in the vicinity of both the sample under investigation and the gradient coils. These eddy currents typically result in undesired degradations of image quality for MRI applications. Their ubiquitous nature has resulted in the development of various approaches to characterize and minimize their impact on image quality. This paper outlines a method that utilizes the magnetic field gradient waveform monitor method to directly measure the temporal evolution of the magnetic field gradient from a step-like input function and extracts the system impulse response. With the basic assumption that the gradient system is sufficiently linear and time invariant to permit system theory analysis, the impulse response is used to determine a pre-equalized (optimized) input waveform that provides a desired gradient response at the output of the system. An algorithm has been developed that calculates a pre-equalized waveform that may be accurately reproduced by the amplifier (is physically realizable) and accounts for system limitations including system bandwidth, amplifier slew rate capabilities, and noise inherent in the initial measurement. Significant improvements in magnetic field gradient waveform fidelity after pre-equalization have been realized and are summarized.

  3. Polymer-based platforms by electric field-assisted techniques for tissue engineering and cancer therapy.

    PubMed

    Guarino, Vincenzo; Cirillo, Valentina; Altobelli, Rosaria; Ambrosio, Luigi

    2015-01-01

    A large variety of processes and tools has been investigated to acquire better knowledge on the natural evolution of healthy or pathological tissues in 3D scaffolds to discover new solutions for tissue engineering and cancer therapy. Among them, electrodynamic techniques allow revisiting old scaffold manufacturing approach by utilizing electrostatic forces as the driving force to assemble fibers and/or particles from an electrically charged solution. By carefully selecting materials and processing conditions, they allow to fine control of characteristic shapes and sizes from micro to sub-micrometric scale and incorporate biopolymers/molecules (e.g., proteins, growth factors) for time- and space-controlled release for use in drug delivery and passive/active targeting. This review focuses on current advances to design micro or nanostructured polymer platforms by electrodynamic techniques, to be used as innovative scaffolds for tissue engineering or as 3D models for preclinical in vitro studies of in vivo tumor growth. PMID:25487005

  4. Angular observables for spin discrimination in boosted diboson final states

    NASA Astrophysics Data System (ADS)

    Buschmann, Malte; Yu, Felix

    2016-09-01

    We investigate the prospects for spin determination of a heavy diboson resonance using angular observables. Focusing in particular on boosted fully hadronic final states, we detail both the differences in signal efficiencies and distortions of differential distributions resulting from various jet substructure techniques. We treat the 2 TeV diboson excess as a case study, but our results are generally applicable to any future discovery in the diboson channel. Scrutinizing ATLAS and CMS analyses at 8 TeV and 13 TeV, we find that the specific cuts employed in these analyses have a tremendous impact on the discrimination power between different signal hypotheses. We discuss modified cuts that can offer a significant boost to spin sensitivity in a post-discovery era. Even without altered cuts, we show that CMS, and partly also ATLAS, will be able to distinguish between spin 0, 1, or 2 new physics diboson resonances at the 2 σ level with 30 fb-1 of 13 TeV data, for our 2 TeV case study.

  5. X-Ray Diffraction Techniques for a Field Instrument: Patterns of Lithologic Provences

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Keaten, R.

    1999-09-01

    Future exploration of Mars will attempt to shed light on the mineralogy of surface materials. Instruments deployed from remote platforms should have the capability to conduct both intensive analyses as well as rapid, reconnaissance surveys while they function in the martian environment as surrogate geologists. In order to accommodate the reconnaissance mode of analysis and to compensate for analytical limitations imposed by the space-flight conditions, data analysis methods are being developed that will permit interpretation of data by recognition of signatures or "fingerprints". Specifically, we are developing a technique which will allow interpretation of diffraction patterns by recognition of characteristic signatures of different lithologic provences. This technique allows a remote vehicle to function in a rapid-scan mode using the lithologic signature to determine where a more thorough analysis is needed. An x-ray diffraction pattern is characterized by the angular positions of diffracted x-rays, x-ray intensity levels and background radiation levels. These elements may be used to identify a generalized x-ray signature. Lithologic signatures are being developed in two ways. A signature is composed using the ideal powder diffraction indices from the mineral assembledge common to a specific lithologic provence. This is then confirmed using a laboratory diffraction pattern of a whole rock powder. Preliminary results comparing the diffraction signatures of the major mineral assembledges common to basalt, carbonate, and evaporite basin deposits indicate that lithologies are differentiable as a "fingerprint". Statistical analyses are being performed to establish the confidence levels of this technique.

  6. X-Ray Diffraction Techniques for a Field Instrument: Patterns of Lithologic Provences

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Keaten, R.

    1999-01-01

    Future exploration of Mars will attempt to shed light on the mineralogy of surface materials. Instruments deployed from remote platforms should have the capability to conduct both intensive analyses as well as rapid, reconnaissance surveys while they function in the martian environment as surrogate geologists. In order to accommodate the reconnaissance mode of analysis and to compensate for analytical limitations imposed by the space-flight conditions, data analysis methods are being developed that will permit interpretation of data by recognition of signatures or "fingerprints". Specifically, we are developing a technique which will allow interpretation of diffraction patterns by recognition of characteristic signatures of different lithologic provences. This technique allows a remote vehicle to function in a rapid-scan mode using the lithologic signature to determine where a more thorough analysis is needed. An x-ray diffraction pattern is characterized by the angular positions of diffracted x-rays, x-ray intensity levels and background radiation levels. These elements may be used to identify a generalized x-ray signature. Lithologic signatures are being developed in two ways. A signature is composed using the ideal powder diffraction indices from the mineral assembledge common to a specific lithologic provence. This is then confirmed using a laboratory diffraction pattern of a whole rock powder. Preliminary results comparing the diffraction signatures of the major mineral assembledges common to basalt, carbonate, and evaporite basin deposits indicate that lithologies are differentiable as a "fingerprint". Statistical analyses are being performed to establish the confidence levels of this technique.

  7. Application of the minimum correlation technique to the correction of the magnetic field measured by magnetometers on spacecraft

    NASA Technical Reports Server (NTRS)

    Mariani, F.

    1979-01-01

    Some aspects of the problem of obtaining precise, absolute determination of the vector of low magnetic fields existing in the interplanetary medium are addressed. In the case of a real S/C, there is always the possibility of a spurious field which includes the spacecraft residual field and/or possible field from the sensors, due to both electronic drifts or changes of the magnetic properties of the sensor core. These latter effects may occur during storage of the sensors prior to launching and/or in-flight. The reliability is demonstrated for a method which postulates that there should be no correlation between changes in measured field magnitude and changes in the measured inclination of the field with respect to any one of three fixed Cartesian component directions. Application of this minimum correlation technique to data from IMP-8 and Helios 1-2 shows it is appropriate for determination of the zero offset corrections of triaxial magnetometers. In general, a number of the order of 1000 consecutive data points is sufficient for a good determination.

  8. Project OPTEX: Field study at a petrochemical facility to assess optical remote sensing and dispersion modeling techniques

    SciTech Connect

    Paien, R.J.; Zwicker, J.O.; Feldman, H.

    1997-12-31

    The American Petroleum Inst. has conducted a field study at a petrochemical facility for the purpose of (1) testing the ability of optical remote sensing (ORS) techniques to characterize fugitive emissions, and (2) assembling ambient and tracer sampler data for evaluating air dispersion models. The study, referred to as the OPTEX (Operational Petrochemical Tracer Experiment) Project, took place during October 1996 at a Texas petrochemical facility. This paper reports on the design of the field study and summarizes the measurements that were obtained in the field. Several aspects of the field study are described in the paper: the types and locations of the emission releases and tracer gases that were used, the deployment of tracer samplers at various downwind distances, the use of open-path FTIR (OP-FTIR) equipment at the site to quantify tracer gas emissions, special short-term tracer gas emissions designed to test the ability of the ORS systems to detect accidental releases, and the use of a Doppler sodar to evaluate vertical profiles of wind and turbulence upwind and downwind of the facility. The data base for this study, as well as that from an earlier field study that took place at the Duke Forest green field site in North Carolina, will be used for evaluating air dispersion model performance and the ability of ORS measurements to quantify fugitive emissions.

  9. 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

  10. 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

  11. 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

  12. On numerical techniques for the transformation to an orthogonal coordinate system aligned with a vector field

    SciTech Connect

    CASTILLO,JOSE E.; OTTO,JAMES S.

    2000-02-11

    The authors explore the use of variational grid-generation to perform alignment of a grid with a given vector field. Variational methods have proven to be a powerful class of grid-generators, but when they are used in alignment, difficulties may arise in treating boundaries due to an incompatibility between geometry and vector field. In this paper, a refinement of the procedure of iterating boundary values is presented. It allows one to control the quality of the grid in the face of the above-mentioned incompatibility. This procedure may be incorporated into any variational alignment algorithm. The authors demonstrate its use with respect to a new quasi-variational alignment method having a particularly simple structure. The latter method is comparable to Knupp's method (see [7]), but avoids use of the Winslow equations.

  13. 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.

  14. On the Methodology of Nematode Extraction from Field Samples: Density Flotation Techniques

    PubMed Central

    Viglierchio, David R.; Yamashita, Tom T.

    1983-01-01

    Density flotation has been frequently used for the extraction of nematodes from field samples. Density flotation curves for four nematode species and five solutes have been prepared. The curves confirm that flotation was governed by several factors: solute density, solute osmotic activity, and physiological properties of the nematode species. Nematode viability and function can be adversely affected by improper selection of solute for density extraction of nematodes; nevertheless, some nematode species can be enriched from mixtures by density and solute selection. PMID:19295831

  15. Optimizing of the Tangential Technique and Supraclavicular Fields in 3 Dimensional Conformal Radiation Therapy for Breast Cancer

    PubMed Central

    Jabbari, Keyvan; Azarmahd, Nazli; Babazade, Shadi; Amouheidari, Alireza

    2013-01-01

    Radiotherapy plays an essential role in the management of breast cancer. Three-dimensional conformal radiation therapy (3D-CRT) is applied based on 3D image information of anatomy of patients. In 3D-CRT for breast cancer one of the common techniques is tangential technique. In this project, various parameters of tangential and supraclavicular fields are optimized. This project has been done on computed tomography images of 100 patients in Isfahan Milad Hospital. All patients have been simulated and all the important organs have been contoured by radiation oncologist. Two techniques in supraclavicular region are evaluated including: 1-A single field (Anterior Posterior [AP]) with a dose of 200 cGy per fraction with 6 MV energy. This is a common technique. 2-Two parallel opposed fields (AP-Posterior Anterior [PA]). The dose of AP was 150 cGy with 6 MV energy and PA 50 cGy with 18 MV. In the second part of the project, the tangential fields has been optimized with change of normalization point in five points: (1) Isocenter (Confluence of rotation gantry axis and collimator axis) (2) Middle of thickest part of breast or middle of inter field distance (IFD) (3) Border between the lung and chest wall (4) Physician's choice (5) Between IFD and isocenter. Dose distributions have been compared for all patients in different methods of supraclavicular and tangential field. In parallel opposed fields average lung dose was 4% more than a single field and the maximum received heart dose was 21.5% less than a single field. The average dose of planning tumor volume (PTV) in method 2 is 2% more than method 1. In general AP-PA method because of a better coverage of PTV is suggested. In optimization of the tangential field all methods have similar coverage of PTV. Each method has spatial advantages and disadvantages. If it is important for the physician to reduce the dose received by the lung and heart, fifth method is suggested since in this method average and maximum received dose

  16. 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.

  17. Spatial performance of RegEM climate field reconstruction techniques in a realistic pseudoproxy context

    NASA Astrophysics Data System (ADS)

    Wang, J.; Emile-Geay, J.; Guillot, D.

    2011-12-01

    Several methods of climate field reconstructions (CFRs) have been introduced in the past few years to estimate past climate variability from proxy data over the Common Era. The pseudoproxy framework has become a tool of choice for assessing the relative merits of such methods. Here we compare four variants of the RegEM algorithm [Schneider, 2001], using a pseudoproxy network mimicking the key spatio-temporal characteristics of the network of Mann et al., 2008 (hereinafter M08); the methods are (1) RegEM TTLS (2) RegEM iTTLS (3) GraphEM and (4) RegEM iRIDGE. To ensure continuity with previous work [Smerdon et al. 2011], pseudoproxy series are designed as a white-noise degraded version of the simulated temperature field [Amman et al. 2007] over 850-1980 C.E. colocated with 1138 M08 proxies. We use signal-to-noise ratios (SNRs) of: ∞ (no noise), 1.0, 0.5 and 0.25, to simulate differences in proxy quality. Two novelties in pseudoproxy design are introduced here: (1) the decrease in proxy availability over time follows that found in M08, (2) a realistic case where the SNR is empirically derived from correlations between each M08 proxy and the HadCRUT3v temperature field. It is found that this realistic SNR is clustered around 0.3, but ranges from 0.1 to 0.8. Verification statistics such as RE, CE, r2, bias, standard deviation ratio and RMSE are presented for each method at each SNR level. The results show that all methods perform relatively well at SNR levels higher than 0.5, but display drastically different performances at lower SNR levels. Compared with results using pseudoproxy network of Mann et al., 1998, (hereinafter MBH98), the reconstruction skill of the M08 network is relatively improved, in line with the findings of Smerdon et al., 2011. Overall, we find that GraphEM and iTTLS tend to produce more robust estimates of the temperature field at low SNR levels than other schemes, while preserving a higher amount of variance in the target field. Ammann, C. M., F

  18. 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

  19. 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

  20. Computed tomography: a powerful imaging technique in the fields of dimensional metrology and quality control

    NASA Astrophysics Data System (ADS)

    Probst, Gabriel; Boeckmans, Bart; Dewulf, Wim; Kruth, Jean-Pierre

    2016-05-01

    X-ray computed tomography (CT) is slowly conquering its space in the manufacturing industry for dimensional metrology and quality control purposes. The main advantage is its non-invasive and non-destructive character. Currently, CT is the only measurement technique that allows full 3D visualization of both inner and outer features of an object through a contactless probing system. Using hundreds of radiographs, acquired while rotating the object, a 3D representation is generated and dimensions can be verified. In this research, this non-contact technique was used for the inspection of assembled components. A dental cast model with 8 implants, connected by a screwed retained bar made of titanium. The retained bar includes a mating interface connection that should ensure a perfect fitting without residual stresses when the connection is fixed with screws. CT was used to inspect the mating interfaces between these two components. Gaps at the connections can lead to bacterial growth and potential inconvenience for the patient who would have to face a new surgery to replace his/hers prosthesis. With the aid of CT, flaws in the design or manufacturing process that could lead to gaps at the connections could be assessed.

  1. 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.

  2. 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.

  3. Enhanced adhesion and field emission of CuO nanowires synthesized by simply modified thermal oxidation technique

    NASA Astrophysics Data System (ADS)

    Tang, C. M.; Wang, Y. B.; Yao, R. H.; Ning, H. L.; Qiu, W. Q.; Liu, Z. W.

    2016-09-01

    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.

  4. 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

  5. Enhanced adhesion and field emission of CuO nanowires synthesized by simply modified thermal oxidation technique

    NASA Astrophysics Data System (ADS)

    Tang, C. M.; Wang, Y. B.; Yao, R. H.; Ning, H. L.; Qiu, W. Q.; Liu, Z. W.

    2016-09-01

    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.

  6. 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.

  7. 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.

  8. 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.

  9. Damage sensitivity investigations of EMI technique on different materials through coupled field analysis

    NASA Astrophysics Data System (ADS)

    Joshi, Bhrigu; Adhikari, Sailesh; Bhalla, Suresh

    2016-04-01

    This paper presents a comparative study through the piezoelectric coupled field analysis mode of finite element method (FEM) on detection of damages of varying magnitude, encompassing three different types of structural materials, using piezo impedance transducers. An aluminum block, a concrete block and a steel block of dimensions 48×48×10 mm were modelled in finite element software ANSYS. A PZT patch of 10×10×0.3 mm was also included in the model as surface bonded on the block. Coupled field analysis (CFA) was performed to obtain the admittance signatures of the piezo sensor in the frequency range of 0-250 kHz. The root mean square deviation (RMSD) index was employed to quantify the degree of variation of the signatures. It was found that concrete exhibited deviation in the signatures only with the change of damping values. However, the other two materials showed variation in the signatures even with changes in density and elasticity values in a small portion of the specimen. The comparative study shows that the PZT patches are more sensitive to damage detection in materials with low damping and the sensitivity typically decreases with increase in the damping.

  10. 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.

  11. Reclamation on Utah's Emery and Alton coal fields: techniques and plant materials

    SciTech Connect

    Ferguson, R.B.; Frischknecht, N.C.

    1985-01-01

    The studies reported on in this paper were designed to provide information on methods to establish vegetation on the soils of the semiarid Emery and Alton coal fields in Utah. No large-scale surface mining of coal has occurred in Utah, so research was conducted on typical potential mine sites following severe disturbance of soil materials. At Emery, primary objectives of the several studies were to evaluate the relative merits of site preparation by gouging, harrowing, and cultipacking in conjunction with the use of alfalfa hay or composted conifer bark as soil amendments. Seed was planted by broadcasting in all trials. At Alton, gouging and the use of hay and composted conifer bark was also tested. Wide varieties of plant species, consisting primarily of shrub and grass species but including several forb and tree species, were planted on different soil materials at both coal field locations. Secondary objectives on both study areas were the evaluation of the use of container-grown shrubs and determination of soil water potentials and soil temperature regimes, as well as documentation of air temperature and precipitation amounts received during the study period. During 5 years at Emery and 6 years at Alton, data were obtained on vegetational parameters such as density, percent cover, and plant yield. Data on survival and growth were obtained on planted shrubs.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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).

  18. 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).

  19. "Virtual" in-vivo bench test for bifurcation stenting with "StentBoost".

    PubMed

    Agostoni, Pierfrancesco; Verheye, Stefan; Vermeersch, Paul; Cornelis, Kristoff; Van Langenhove, Glenn

    2009-04-01

    "StentBoost" is a new angiographic technique that allows improved angiographic visualization of stents deployed in coronary arteries, by enhancing the X-ray focus of the region where the stent is placed. Using this technique we were able to assess the deformation and the expansion of a stent deployed to treat a bifurcation lesion between the mid-left anterior descending (LAD) artery and a big second diagonal branch, during sequential inflations of: (1) the stent per se in the LAD, (2) the ostium of the diagonal branch through the stent struts, (3) the stent again with a non compliant balloon, and (4) both branches with the kissing balloon technique. "StentBoost" guided our clinical and angiographic decision-making process and allowed us to create a "virtual" bench test of the stent deployed at the level of the bifurcation treated.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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).

  7. ATS 6 EMI field measurements techniques and results. [anechoic chamber scale model testing

    NASA Technical Reports Server (NTRS)

    Afifi, M. S.; Keiser, B. E.

    1974-01-01

    At the present time 'Applications Technology Satellite (ATS)-6' is the world's largest communication satellite. It handles telecommunications in the frequency range of 40 - 30,000 MHz. Power levels on board the spacecraft range from -110 dBm to 52.5 dBw. Consequently considerable care was required in the design and test of this spacecraft, in order to provide assurances that the spacecraft would perform properly in its own RF environments. The testing was performed first by placing the earth viewing module (EVM) in a specially constructed 'small' anechoic chamber with an overhead parabolic reflector section, of 8' in diameter, instead of the 30' reflector of the full scale design. The near field analysis of this paper proves that this test configuration leads to a desirable overtest for the spacecraft. The test requirements, procedure and results are also explained.

  8. 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

  9. 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.

  10. Effects of sprint and plyometrics training on field sport acceleration technique.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Callaghan, Samuel J; Jeffriess, Matthew D

    2014-07-01

    The mechanisms for speed performance improvement from sprint training and plyometrics training, especially relating to stance kinetics, require investigation in field sport athletes. This study determined the effects of sprint training and plyometrics training on 10-m sprint time (0-5, 5-10, and 0-10 m intervals), step kinematics (step length and frequency, contact and flight time), and stance kinetics (first, second, and last contact relative vertical [VF, VI], horizontal [HF, HI], and resultant [RF, RI] force and impulse; resultant ground reaction force angle [RFθ]; ratio of horizontal to resultant force [RatF]) during a 10-m sprint. Sixteen male field sport athletes were allocated into sprint training (ST) and plyometrics training (PT) groups according to 10-m sprint time; independent samples t-tests (p ≤ 0.05) indicated no between-group differences. Training involved 2 sessions per week for 6 weeks. A repeated measures analysis of variance (p ≤ 0.05) determined within- and between-subject differences. Both groups decreased 0-5 and 0-10 m time. The ST group increased step length by ∼15%, which tended to be greater than step length gains for the PT group (∼7%). The ST group reduced first and second contact RFθ and RatF, and second contact HF. Second contact HI decreased for both groups. Results indicated a higher post-training emphasis on VF production. Vertical force changes were more pronounced for the PT group for the last contact, who increased or maintained last contact VI, RF, and RI to a greater extent than the ST group. Sprint and plyometrics training can improve acceleration, primarily through increased step length and a greater emphasis on VF.

  11. Development of a field-portable small-size impedance analyzer for structural health monitoring using the electromechanical impedance technique

    NASA Astrophysics Data System (ADS)

    Giurgiutiu, Victor; Xu, Buli

    2004-07-01

    Electromechanical (E/M) impedance method is emerging as an effective and powerful technique for structural health monitoring. The E/M impedance method utilizes as its main apparatus an impedance analyzer that reads the in-situ E/M impedance of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. Laboratory-type impedance analyzers (e.g. HP4194) are bulky, heavy, and expensive. They cannot be easily carried into the field for on-site structural health monitoring. To address this issue, means of to reduce the size of the impedance analyzer making the impedance analyzer more compact and field-portable are explored. In this paper, we present a systematic approach to the development of a field-portable small-size impedance analyzer for structural health monitoring using the electromechanical impedance technique. Our approach consists of several developmental stages. First, we perform a simulation of the E/M Impedance technique and develop the software tools for analyzing the signal in a fast and efficient way while maintaining the desired accuracy. The objective of this signal processing part is to obtain the complex impedance, ZR+iZI)=|Z| angle arg Z, at a number of frequencies in a predetermined range. Several signal processing methods were explored such as: (a) integration method; (b) correlation method; (c) Discrete Fourier transform (DFT) method. Second, we discuss the hardware issues associated with the implementation of this approach. The hardware system architecture consists of several blocks: (a) reference signal generation; (b) voltage and current measurements; and (c) digital signal acquisition and processing. Practical results obtained during proof-of-concept experiments are presented and comparatively examined.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. [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

  18. 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.

  19. [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.

  20. 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.

  1. 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

  2. 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

  3. Thin Fluorine-Doped Tin Oxide Films Prepared Using an Electric Field-Modified Spray Pyrolysis Deposition Technique

    NASA Astrophysics Data System (ADS)

    Gupta, Archana; Pandya, Dinesh K.; Kashyap, Subhash C.

    2004-12-01

    Very thin fluorine-doped tin oxide films (60-70 nm) were prepared on glass substrates at low deposition temperatures (275-300°C), these films showed an electrical resistivity of 3.2 × 10-4Ω-cm and a transparency of 88% at 625 nm with the application of a dc electric field on the film surface during growth using a spray pyrolysis deposition technique. In this first study of its kind, the applied electric field during growth by spray pyrolysis resulted in the reduction in the critical thickness and the increases in both the electrical conductivity and transparency of continuous films. The obtained X-ray diffraction (XRD) patterns showed that the films prepared with an electric field were polycrystalline, whereas those prepared without an electric field were amorphous. This method shows potential for producing very thin oxide films at a low deposition temperature with a high growth rate, an enhanced optical quality and an improved electrical conductivity.

  4. 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.

  5. 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.

  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. 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

  8. 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

  9. 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.

  10. Site characterization techniques used at a low-level waste shallow land burial field demonstration facility

    SciTech Connect

    Davis, E.C.; Boegly, W.J. Jr.; Rothschild, E.R.; Spalding, B.P.; Vaughan, N.D.; Haase, C.S.; Huff, D.D.; Lee, S.Y.; Walls, E.C.; Newbold, J.D.

    1984-07-01

    The Environmental Sciences Division of the Oak Ridge National Laboratory has been investigating improved shallow land burial technology for application in the humd eastern United States. As part of this effort, a field demonstration facility (Engineered Test Facility, or ETF) has been established in Solid Waste Storage Area 6 for purposes of investigatig the ability of two trench treatments (waste grouting prior to cover emplacement and waste isolation with trench liners) to prevent water-waste contact and thus minimize waste leaching. As part of the experimental plan, the ETF site has been characterized for purposes of constructing a hydrologic model. Site characterization is an extremely important component of the waste disposal site selection process; during these activities, potential problems, which might obviate the site from further consideration, may be found. This report describes the ETF site characterization program and identifies and, where appropriate, evaluates those tests that are of most value in model development. Specific areas covered include site geology, soils, and hydrology. Each of these areas is further divided into numerous subsections, making it easy for the reader to examine a single area of interest. Site characterization is a multidiscipliary endeavor with voluminous data, only portions of which are presented and analyzed here. The information in this report is similar to that which will be required of a low-level waste site developer in preparing a license application for a potential site in the humid East, (a discussion of licensing requirements is beyond its scope). Only data relevant to hydrologic model development are included, anticipating that many of these same characterization methods will be used at future disposal sites with similar water-related problems.

  11. 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.

  12. 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.

  13. Infrared thermoimage analysis as real time technique to evaluate in-field pesticide spraying quality distribution

    NASA Astrophysics Data System (ADS)

    Menesatti, P.; Biocca, M.

    2007-09-01

    Tests and calibration of sprayers have been considered a very important task for chemicals use reduction in agriculture and for improvement of plant phytosanitary protection. A reliable, affordable and easy-to-use method to observe the distribution in the field is required and the infrared thermoimage analysis can be considered as a potential method based on non-contact imaging technologies. The basic idea is that the application of colder water (10 °C less) than the leaves surface makes it possible to distinguish and measure the targeted areas by means of a infrared thermoimage analysis based on significant and time persistent thermal differences. Trials were carried out on a hedge of Prunus laurocerasus, 2.1 m height with an homogenous canopy. A trailed orchard sprayer was employed with different spraying configurations. A FLIR TM (S40) thermocamera was used to acquire (@ 50 Hz) thermal videos, in a fixed position, at frame rate of 10 images/s, for nearly 3 min. Distribution quality was compared to the temperature differences obtained from the thermal images between pre-treatment and post-treatment (ΔT)., according two analysis: time-trend of ΔT average values for different hedge heights and imaging ΔT distribution and area coverage by segmentation in k means clustering after 30 s of spraying. The chosen spraying configuration presented a quite good distribution for the entire hedge height with the exclusion of the lower (0-1 m from the ground) and the upper part (>1.9 m). Through the image segmentation performed of ΔT image by k-means clustering, it was possible to have a more detailed and visual appreciation of the distribution quality among the entire hedge. The thermoimage analysis revealed interesting potentiality to evaluate quality distribution from orchards sprayers.

  14. 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

  15. Simultaneous integrated boost plan comparison of volumetric-modulated arc therapy and sliding window intensity-modulated radiotherapy for whole pelvis irradiation of locally advanced prostate cancer.

    PubMed

    Riou, Olivier; Regnault de la Mothe, Pauline; Azria, David; Aillères, Norbert; Dubois, Jean-Bernard; Fenoglietto, Pascal

    2013-07-08

    Concurrent radiotherapy to the pelvis plus a prostate boost with long-term androgen deprivation is a standard of care for locally advanced prostate cancer. IMRT has the ability to deliver highly conformal dose to the target while lowering irradiation of critical organs around the prostate. Volumetric-modulated arc therapy is able to reduce treatment time, but its impact on organ sparing is still controversial when compared to static gantry IMRT. We compared the two techniques in simultaneous integrated boost plans. Ten patients with locally advanced prostate cancer were included. The planning target volume (PTV) 1 was defined as the pelvic lymph nodes, the prostate, and the seminal vesicles plus setup margins. The PTV2 consisted of the prostate with setup margins. The prescribed doses to PTV1 and PTV2 were 54 Gy in 37 fractions and 74 Gy in 37 fractions, respectively. We compared simultaneous integrated boost plans by means of either a seven coplanar static split fields IMRT, or a one-arc (RA1) and a two-arc (RA2) RapidArc planning. All three techniques allowed acceptable homogeneity and PTV coverage. Static IMRT enabled a better homogeneity for PTV2 than RapidArc techniques. Sliding window IMRT and VMAT permitted to maintain doses to OAR within acceptable levels with a low risk of side effects for each organ. VMAT plans resulted in a clinically and statistically significant reduction in doses to bladder (mean dose IMRT: 50.1 ± 4.6Gy vs. mean dose RA2: 47.1 ± 3.9 Gy, p = 0.037), rectum (mean dose IMRT: 44± 4.5 vs. mean dose RA2: 41.6 ± 5.5 Gy, p = 0.006), and small bowel (V30 IMRT: 76.47 ± 14.91% vs. V30 RA2: 47.49 ± 16.91%, p = 0.002). Doses to femoral heads were higher with VMAT but within accepted constraints. Our findings suggest that simultaneous integrated boost plans using VMAT and sliding window IMRT allow good OAR sparing while maintaining PTV coverage within acceptable levels.

  16. [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.

  17. [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

  18. 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

  19. 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

  20. 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.

  1. Hybrid Recovery-less Method Soft Switching Boost Chopper Circuit

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masayoshi; Toda, Hirotaka; Kawashima, Takahiro; Yoshida, Toshiyuki

    The conventional recovery-less boost type converter cannot achieve the soft switching operation in case of the turn off transition. In this paper, the novel hybrid recovery-less boost type converter, which can achieve the soft switching turn off transition, is proposed. Furthermore, the proposed hybrid recovery-less boost type converter has the switch function between the conventional recovery-less mode and the proposed soft switching mode. In general, the efficiency in the soft switching converter is less than the hard switching in case of the lower output power condition. However, using the switch function of the proposed boost type converter, the hybrid recovery-less boost type converter can achieve the high efficiency performance in the whole output power area in spite of the soft switching operation. The proposed hybrid recovery-less boost type converter is evaluated and discussed from experimental point of view.

  2. USGS Menlo Park GPS Data Processing Techniques and Derived North America Velocity Field (Invited)

    NASA Astrophysics Data System (ADS)

    Svarc, J. L.; Murray-Moraleda, J. R.; Langbein, J. O.

    2010-12-01

    The U.S. Geological Survey in Menlo Park routinely conducts repeated GPS surveys of geodetic markers throughout the western United States using dual-frequency geodetic GPS receivers. We combine campaign, continuous, and semi-permanent data to present a North America fixed velocity field for regions in the western United States. Mobile campaign-based surveys require less up-front investment than permanently monumented and telemetered GPS systems, and hence have achieved a broad and dense spatial coverage. The greater flexibility and mobility comes at the cost of greater uncertainties in individual daily position solutions. We also routinely process continuous GPS data collected at PBO stations operated by UNAVCO along with data from other continuous GPS networks such as BARD, PANGA, and CORS operated by other agencies. We have broken the Western US into several subnetworks containing approximately 150-250 stations each. The data are processed using JPL’s GIPSY-OASIS II release 5.0 software using a modified precise positioning strategy (Zumberge and others, 1997). We use the “ambizap” code provided by Geoff Blewitt (Blewitt, 2008) to fix phase ambiguities in continuous networks. To mitigate the effect of common mode noise we use the positions of stations in the network with very long, clean time series (i.e. those with no large outliers or offsets) to transform all position estimates into “regionally filtered” results following the approach of Hammond and Thatcher (2007). Velocity uncertainties from continuously operated GPS stations tend to be about 3 times smaller than those from campaign data. Langbein (2004) presents a maximum likelihood method for fitting a time series employing a variety of temporal noise models. We assume that GPS observations are contaminated by a combination of white, flicker, and random walk noise. For continuous and semi-permanent time series longer than 2 years we estimate these values, otherwise we fix the amplitudes of these

  3. 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.

  4. Boosting salt resistance of short antimicrobial peptides.

    PubMed

    Chu, Hung-Lun; Yu, Hui-Yuan; Yip, Bak-Sau; Chih, Ya-Han; Liang, Chong-Wen; Cheng, Hsi-Tsung; Cheng, Jya-Wei

    2013-08-01

    The efficacies of many antimicrobial peptides are greatly reduced under high salt concentrations, therefore limiting their use as pharmaceutical agents. Here, we describe a strategy to boost salt resistance and serum stability of short antimicrobial peptides by adding the nonnatural bulky amino acid β-naphthylalanine to their termini. The activities of the short salt-sensitive tryptophan-rich peptide S1 were diminished at high salt concentrations, whereas the activities of its β-naphthylalanine end-tagged variants were less affected.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Jet substructures of boosted polarized top quarks

    NASA Astrophysics Data System (ADS)

    Kitadono, Yoshio; Li, Hsiang-nan

    2014-06-01

    We study jet substructures of a boosted polarized top quark, which undergoes the semileptonic decay t→bℓν, in the perturbative QCD framework. The jet mass distribution (energy profile) is factorized into the convolution of a hard top-quark decay kernel with the bottom-quark jet function (jet energy function). Computing the hard kernel to the leading order in QCD and inputting the latter functions from the resummation formalism, we observe that the jet mass distribution is not sensitive to the helicity of the top quark, but the energy profile is: energy is accumulated faster within a left-hand top jet than within a right-hand one, a feature related to the V-A structure of weak interaction. It is pointed out that the energy profile is a simple and useful jet observable for helicity discrimination of a boosted top quark, which helps identification of physics beyond the standard model at the Large Hadron Collider. The extension of our analysis to other jet substructures, including those associated with a hadronically decaying polarized top quark, is proposed.

  15. Brain glucosamine boosts protective glucoprivic feeding.

    PubMed

    Osundiji, Mayowa A; Zhou, Ligang; Shaw, Jill; Moore, Stephen P; Yueh, Chen-Yu; Sherwin, Robert; Heisler, Lora K; Evans, Mark L

    2010-04-01

    The risk of iatrogenic hypoglycemia is increased in diabetic patients who lose defensive glucoregulatory responses, including the important warning symptom of hunger. Protective hunger symptoms during hypoglycemia may be triggered by hypothalamic glucose-sensing neurons by monitoring changes downstream of glucose phosphorylation by the specialized glucose-sensing hexokinase, glucokinase (GK), during metabolism. Here we investigated the effects of intracerebroventricular (ICV) infusion of glucosamine (GSN), a GK inhibitor, on food intake at normoglycemia and protective feeding responses during glucoprivation and hypoglycemia in chronically catheterized rats. ICV infusion of either GSN or mannoheptulose, a structurally different GK inhibitor, dose-dependently stimulated feeding at normoglycemia. Consistent with an effect of GSN to inhibit competitively glucose metabolism, ICV coinfusion of d-glucose but not l-glucose abrogated the orexigenic effect of ICV GSN at normoglycemia. Importantly, ICV infusion of a low GSN dose (15 nmol/min) that was nonorexigenic at normoglycemia boosted feeding responses to glucoprivation in rats with impaired glucose counterregulation. ICV infusion of 15 nmol/min GSN also boosted feeding responses to threatened hypoglycemia in rats with defective glucose counterregulation. Altogether our findings suggest that GSN may be a potential therapeutic candidate for enhancing defensive hunger symptoms during hypoglycemia.

  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. Imaging of the magnetic field structure in megagauss plasmas by combining pulsed polarimetry with an optical Kerr effect shutter technique.

    PubMed

    Smith, R J

    2010-10-01

    Pulsed polarimetry in combination with a high speed photographic technique based on the optical Kerr effect is described. The backscatter in a pulsed polarimeter is directed through a scattering cell and photographed using an ∼1 ps shutter, essentially freezing the intensity pattern. The image provides both the local electron density and magnetic field distributions along and transverse to the laser sightline. Submillimeter spatial resolution is possible for probing wavelengths in the visible due to the high densities and strong optical activity. Pulsed polarimetry is thereby extended to centimeter-sized plasmas with n(e)>10(19)-10(20) cm(-3) and B>20-100 T (MG) produced by multiterawatt, multimega-ampere electrical drivers, wire Z pinches, and liner imploded magnetized plasmas. PMID:21033885

  18. Imaging of the magnetic field structure in megagauss plasmas by combining pulsed polarimetry with an optical Kerr effect shutter technique

    SciTech Connect

    Smith, R. J.

    2010-10-15

    Pulsed polarimetry in combination with a high speed photographic technique based on the optical Kerr effect is described. The backscatter in a pulsed polarimeter is directed through a scattering cell and photographed using an {approx}1 ps shutter, essentially freezing the intensity pattern. The image provides both the local electron density and magnetic field distributions along and transverse to the laser sightline. Submillimeter spatial resolution is possible for probing wavelengths in the visible due to the high densities and strong optical activity. Pulsed polarimetry is thereby extended to centimeter-sized plasmas with n{sub e}>10{sup 19}-10{sup 20} cm{sup -3} and B>20-100 T (MG) produced by multiterawatt, multimega-ampere electrical drivers, wire Z pinches, and liner imploded magnetized plasmas.

  19. Field enhancement and resonance phenomena in complex three-dimensional nanoparticles: efficient computation using the source-model technique.

    PubMed

    Ishay, Yakir; Leviatan, Yehuda; Bartal, Guy

    2014-05-15

    We present a semi-analytical method for computing the electromagnetic field in and around 3D nanoparticles (NP) of complex shape and demonstrate its power via concrete examples of plasmonic NPs that have nonsymmetrical shapes and surface areas with very small radii of curvature. In particular, we show the three axial resonances of a 3D cashew-nut and the broadband response of peanut-shell NPs. The method employs the source-model technique along with a newly developed intricate source distributing algorithm based on the surface curvature. The method is simple and can outperform finite-difference time domain and finite-element-based software tools in both its efficiency and accuracy. PMID:24978226

  20. Construction techniques for the Taklamakan Desert Highway: research on the construction materials and the results of field tests

    NASA Astrophysics Data System (ADS)

    Jin, Changning; Dong, Zhibao; Li, Zhinong

    2006-03-01

    After conducting many laboratory and field experiments, several key technical issues related to the construction of China’s Taklamakan Desert Highway have been satisfactorily resolved. In particular, considerable progress has been made on the dry compaction of a sand sub-base, road design parameters, the creation of a structure that combines a sub-grade and asphalt pavement, analysis of the stability of a sand sub-base strengthened with geotextiles, and on the development of a complete set of construction techniques. The achievements of this research were successfully applied for the first time in the Taklamakan Desert, where the environmental conditions are extremely harsh. The results suggest that the construction of this highway was economical and that the simple construction methods produced a reliable highway. The resulting highway is believed to be the world’s first long-distance graded highway running through a huge desert with migrating dunes.

  1. Use of Geophysical and Remote Sensing Techniques During the Comprehensive Test Ban Treaty Organization's Integrated Field Exercise 2014

    NASA Astrophysics Data System (ADS)

    Labak, Peter; Sussman, Aviva; Rowlands, Aled; Chiappini, Massimo; Malich, Gregor; MacLeod, Gordon; Sankey, Peter; Sweeney, Jerry; Tuckwell, George

    2016-04-01

    The Integrated Field Exercise of 2014 (IFE14) was a field event held in the Hashemite Kingdom of Jordan (with concurrent activities in Austria) that tested the operational and technical capabilities of a Comprehensive Test Ban Treaty's (CTBT) on-site inspection (OSI). During an OSI, up to 40 inspectors search a 1000km2 inspection area for evidence of a nuclear explosion. Over 250 experts from ~50 countries were involved in IFE14 (the largest simulation of an OSI to date) and worked from a number of different directions, such as the Exercise Management and Control Teams to execute the scenario in which the exercise was played, to those participants performing as members of the Inspection Team (IT). One of the main objectives of IFE14 was to test Treaty allowed inspection techniques, including a number of geophysical and remote sensing methods. In order to develop a scenario in which the simulated exercise could be carried out, a number of physical features in the IFE14 inspection area were designed and engineered by the Scenario Task Force Group (STF) that the IT could detect by applying the geophysical and remote sensing inspection technologies, as well as other techniques allowed by the CTBT. For example, in preparation for IFE14, the STF modeled a seismic triggering event that was provided to the IT to prompt them to detect and localize aftershocks in the vicinity of a possible explosion. Similarly, the STF planted shallow targets such as borehole casings and pipes for detection by other geophysical methods. In addition, airborne technologies, which included multi-spectral imaging, were deployed such that the IT could identify freshly exposed surfaces, imported materials and other areas that had been subject to modification. This presentation will introduce the CTBT and OSI, explain the IFE14 in terms of goals specific to geophysical and remote sensing methods, and show how both the preparation for and execution of IFE14 meet those goals.

  2. Comparison of three techniques for modeling the Earth's gravity field on the basis of a satellite orbit

    NASA Astrophysics Data System (ADS)

    Ditmar, P.; van Eck van der Sluijs, A.

    2003-12-01

    At present, there are three techniques for the computation of the Earth's gravity field from a satellite orbit: (i) the "classical" approach based on the integration of variational equations (IVEA); (ii) the energy balance approach (EBA); (iii) the acceleration approach (AA), which directly relates the satellite accelerations to the gravity field in accordance with Newton's second law. Most of the results have been obtained so far with the IVEA and EBA. The AA is believed to be inferior because the double differentiation needed to convert the satellite orbit into the satellite accelerations amplifies data noise dramatically. We show that that a poor performance of the AA is a myth. One can easily prove that the solution of an inverse problem is invariant with respect to the linear transformation of the data vector of the kind d' = B d (where d is the original data vector, d' is the transformed data vector, and B is the transformation matrix) provided that the matrix B is square and invertible. The only pre-requisite is that the optimal estimation procedure is followed, including the usage of the properly transformed covariance matrix: Cd' = B Cd BT. In other words, such data vectors d' and d are equivalent. It is easy to show that the satellite positions and satellite accelerations are two nearly equivalent data sets (in order to reach a strict equivalence, the latter can be supplied, e.g., with the initial state vector). Therefore, these data sets may result in nearly the same gravity field model. A decision which technique is preferable should be made on the basis of practical considerations, e.g. the numerical efficiency. According to our experience, the AA leads to a much faster computational scheme than the IVEA. Furthermore, we have considered the EBA. It is easy to show that a set of kinetic energy measurements is nearly equivalent to a set of along-track satellite accelerations. The other two components of the acceleration vectors are ignored by the EBA

  3. Marine Biological Field Techniques.

    ERIC Educational Resources Information Center

    Awkerman, Gary L.

    This publication is designed for use in a standard science curricula to develop oceanologic manifestations of certain science topics. Included are teacher guides, student activities, and demonstrations designed to impart ocean science understanding to high school students. It could be a useful instructional tool for any high school student field…

  4. Detecting brain tumor in computed tomography images using Markov random fields and fuzzy C-means clustering techniques

    NASA Astrophysics Data System (ADS)

    Abdulbaqi, Hayder Saad; Jafri, Mohd Zubir Mat; Omar, Ahmad Fairuz; Mustafa, Iskandar Shahrim Bin; Abood, Loay Kadom

    2015-04-01

    Brain tumors, are an abnormal growth of tissues in the brain. They may arise in people of any age. They must be detected early, diagnosed accurately, monitored carefully, and treated effectively in order to optimize patient outcomes regarding both survival and quality of life. Manual segmentation of brain tumors from CT scan images is a challenging and time consuming task. Size and location accurate detection of brain tumor plays a vital role in the successful diagnosis and treatment of tumors. Brain tumor detection is considered a challenging mission in medical image processing. The aim of this paper is to introduce a scheme for tumor detection in CT scan images using two different techniques Hidden Markov Random Fields (HMRF) and Fuzzy C-means (FCM). The proposed method has been developed in this research in order to construct hybrid method between (HMRF) and threshold. These methods have been applied on 4 different patient data sets. The result of comparison among these methods shows that the proposed method gives good results for brain tissue detection, and is more robust and effective compared with (FCM) techniques.

  5. Detecting brain tumor in computed tomography images using Markov random fields and fuzzy C-means clustering techniques

    SciTech Connect

    Abdulbaqi, Hayder Saad; Jafri, Mohd Zubir Mat; Omar, Ahmad Fairuz; Mustafa, Iskandar Shahrim Bin; Abood, Loay Kadom

    2015-04-24

    Brain tumors, are an abnormal growth of tissues in the brain. They may arise in people of any age. They must be detected early, diagnosed accurately, monitored carefully, and treated effectively in order to optimize patient outcomes regarding both survival and quality of life. Manual segmentation of brain tumors from CT scan images is a challenging and time consuming task. Size and location accurate detection of brain tumor plays a vital role in the successful diagnosis and treatment of tumors. Brain tumor detection is considered a challenging mission in medical image processing. The aim of this paper is to introduce a scheme for tumor detection in CT scan images using two different techniques Hidden Markov Random Fields (HMRF) and Fuzzy C-means (FCM). The proposed method has been developed in this research in order to construct hybrid method between (HMRF) and threshold. These methods have been applied on 4 different patient data sets. The result of comparison among these methods shows that the proposed method gives good results for brain tissue detection, and is more robust and effective compared with (FCM) techniques.

  6. Quantitative Density Measurement of the Interaction Field of Side Jet and Cross Flow by Colored-Grid Background Oriented Schlieren (CGBOS) Technique

    NASA Astrophysics Data System (ADS)

    Ota, M.; Inage, T.; Kikuma, Y.; Kawakami, H.; Miwa, Y.; Maeno, K.

    The Background Oriented Schlieren (BOS) technique proposed by Meier [1] enables us to take a quantitative density measurement of a flow field with computeraided image analysis. In the past several years, the BOS technique has been applied in various experiments [2],[3].

  7. SVD-Based Technique for Interference Cancellation and Noise Reduction in NMR Measurement of Time-Dependent Magnetic Fields.

    PubMed

    Chen, Wenjun; Ma, Hong; Yu, De; Zhang, Hua

    2016-03-04

    A nuclear magnetic resonance (NMR) experiment for measurement of time-dependent magnetic fields was introduced. To improve the signal-to-interference-plus-noise ratio (SINR) of NMR data, a new method for interference cancellation and noise reduction (ICNR) based on singular value decomposition (SVD) was proposed. The singular values corresponding to the radio frequency interference (RFI) signal were identified in terms of the correlation between the FID data and the reference data, and then the RFI and noise were suppressed by setting the corresponding singular values to zero. The validity of the algorithm was verified by processing the measured NMR data. The results indicated that, this method has a significantly suppression of RFI and random noise, and can well preserve the FID signal. At present, the major limitation of the proposed SVD-based ICNR technique is that the threshold value for interference cancellation needs to be manually selected. Finally, the inversion waveform of the applied alternating magnetic field was given by fitting the processed experimental data.

  8. Full-field swept-source optical coherence tomography with phase-shifting techniques for skin cancer detection

    NASA Astrophysics Data System (ADS)

    Krauter, J.; Boettcher, T.; Körner, K.; Gronle, M.; Osten, W.; Passilly, N.; Froehly, L.; Perrin, S.; Gorecki, C.

    2015-05-01

    The EU-funded project VIAMOS1 proposes an optical coherence tomography system (OCT) for skin cancer detection, which combines full-field and full-range swept-source OCT in a multi-channel sensor for parallel detection. One of the project objectives is the development of new fabrication technologies for micro-optics, which makes it compatible to Micro-Opto-Electromechanical System technology (MOEMS). The basic system concept is a wafer-based Mirau interferometer array with an actuated reference mirror, which enables phase shifted interferogram detection and therefore reconstruction of the complex phase information, resulting in a higher measurement range with reduced image artifacts. This paper presents an experimental one-channel on-bench OCT system with bulk optics, which serves as a proof-of-concept setup for the final VIAMOS micro-system. It is based on a Linnik interferometer with a wavelength tuning light source and a camera for parallel A-Scan detection. Phase shifting interferometry techniques (PSI) are used for the suppression of the complex conjugate artifact, whose suppression reaches 36 dB. The sensitivity of the system is constant over the full-field with a mean value of 97 dB. OCT images are presented of a thin membrane microlens and a biological tissue (onion) as a preliminary demonstration.

  9. SVD-Based Technique for Interference Cancellation and Noise Reduction in NMR Measurement of Time-Dependent Magnetic Fields

    PubMed Central

    Chen, Wenjun; Ma, Hong; Yu, De; Zhang, Hua

    2016-01-01

    A nuclear magnetic resonance (NMR) experiment for measurement of time-dependent magnetic fields was introduced. To improve the signal-to-interference-plus-noise ratio (SINR) of NMR data, a new method for interference cancellation and noise reduction (ICNR) based on singular value decomposition (SVD) was proposed. The singular values corresponding to the radio frequency interference (RFI) signal were identified in terms of the correlation between the FID data and the reference data, and then the RFI and noise were suppressed by setting the corresponding singular values to zero. The validity of the algorithm was verified by processing the measured NMR data. The results indicated that, this method has a significantly suppression of RFI and random noise, and can well preserve the FID signal. At present, the major limitation of the proposed SVD-based ICNR technique is that the threshold value for interference cancellation needs to be manually selected. Finally, the inversion waveform of the applied alternating magnetic field was given by fitting the processed experimental data. PMID:26959024

  10. Appraisal of Artificial Screening Techniques of Tomato to Accurately Reflect Field Performance of the Late Blight Resistance

    PubMed Central

    Nowakowska, Marzena; Nowicki, Marcin; Kłosińska, Urszula; Maciorowski, Robert; Kozik, Elżbieta U.

    2014-01-01

    Late blight (LB) caused by the oomycete Phytophthora infestans continues to thwart global tomato production, while only few resistant cultivars have been introduced locally. In order to gain from the released tomato germplasm with LB resistance, we compared the 5-year field performance of LB resistance in several tomato cultigens, with the results of controlled conditions testing (i.e., detached leaflet/leaf, whole plant). In case of these artificial screening techniques, the effects of plant age and inoculum concentration were additionally considered. In the field trials, LA 1033, L 3707, L 3708 displayed the highest LB resistance, and could be used for cultivar development under Polish conditions. Of the three methods using controlled conditions, the detached leaf and the whole plant tests had the highest correlation with thefield experiments. The plant age effect on LB resistance in tomato reported here, irrespective of the cultigen tested or inoculum concentration used, makes it important to standardize the test parameters when screening for resistance. Our results help show why other reports disagree on LB resistance in tomato. PMID:25279467

  11. Surface tension measurement techniques of magnetic fluids at an interface between different fluids using perpendicular field instability

    NASA Astrophysics Data System (ADS)

    Amin, M. Shahrooz; Elborai, Shihab; Lee, Se-Hee; He, Xiaowei; Zahn, Markus

    2005-05-01

    Two measurement techniques to determine the surface tension of ferrofluids using the perpendicular field instability are described. Four ferrofluid layers were examined with magnetic field applied perpendicularly to the surface of (1) oil-based ferrofluid in air; (2) water-based ferrofluid in air, (3) oil-based ferrofluid, and (4) fluorocarbon-based ferrofluid, both below a blend of 50% n-Propyl alcohol and 50% deionized water (propanol). Surface tension was accurately calculated by utilizing the measured Taylor wavelength from measurements of incipient fluid instability peaks and the measured densities of fluids. For cases (1) and (2), the calculated surface tension values were in good agreement with a tensiometer measurement. No accurate tensiometer measurements were conducted for the superposed liquids (3) and (4) since accurate tensiometer measurements are difficult for a two fluid layer system. The second less accurate method used the ferrofluid's nonlinear Langevin magnetization characteristics to compute the surface tension from incipience of interfacial instability conditions. Discrepancies between the surface tensions measured by the two methods were probably due to the ferrofluid particle size distributions and the strong dependence of the ferrofluid magnetization on particle size.

  12. Intensity-modulated radiation therapy (IMRT) of cancers of the head and neck: Comparison of split-field and whole-field techniques

    SciTech Connect

    Dabaja, Bouthaina; Salehpour, Mohammad R.; Rosen, Isaac; Tung, Sam; Morrison, William H.; Ang, K. Kian; Garden, Adam S. . E-mail: agarden@mdanderson.org

    2005-11-15

    Background: Oropharynx cancers treated with intensity-modulated radiation (IMRT) are often treated with a monoisocentric or half-beam technique (HB). IMRT is delivered to the primary tumor and upper neck alone, while the lower neck is treated with a matching anterior beam. Because IMRT can treat the entire volume or whole field (WF), the primary aim of the study was to test the ability to plan cases using WF-IMRT while obtaining an optimal plan and acceptable dose distribution and also respecting normal critical structures. Methods and Materials: Thirteen patients with early-stage oropharynx cancers had treatment plans created with HB-IMRT and WF-IMRT techniques. Plans were deemed acceptable if they met the planning guidelines (as defined or with minor violations) of the Radiation Therapy Oncology Group protocol H0022. Comparisons included coverage to the planning target volume (PTV) of the primary (PTV66) and subclinical disease (PTV54). We also compared the ability of both techniques to respect the tolerance of critical structures. Results: The volume of PTV66 treated to >110% was less in 9 of the 13 patients in the WF-IMRT plan as compared to the HB-IMRT plan. The calculated mean volume receiving >110% for all patients planned with WF-IMRT was 9.3% (0.8%-25%) compared to 13.7% (2.7%-23.7%) with HB-IMRT (p = 0.09). The PTV54 volume receiving >110% of dose was less in 10 of the 13 patients planned with WF-IMRT compared to HB-IMRT. The mean doses to all critical structures except the larynx were comparable with each plan. The mean dose to the larynx was significantly less (p = 0.001), 18.7 Gy, with HB-IMRT compared to 47 Gy with WF-IMRT. Conclusions: Regarding target volumes, acceptable plans can be generated with either WF-IMRT or HB-IMRT. WF-IMRT has an advantage if uncertainty at the match line is a concern, whereas HB-IMRT, particularly in cases not involving the base of tongue, can achieve much lower doses to the larynx.

  13. Solar Wind Magnetic Field Turbulence at Ion Kinetic Scales Measured by Cluster Using k-filtering Technique

    NASA Astrophysics Data System (ADS)

    Li, X.; Roberts, O. W.; Jeska, L.; Li, B.; Lu, Q.

    2014-12-01

    The nature of turbulence at kinetic scales is important since turbulence energy is believed to dissipate as heat at these scales. Here we report our several work on the solar wind turbulence at ion kinetic scales using the k-filtering technique. We found evidence of ion cyclotron resonance in solar wind intervals. In the wave vector space, in addition to the commonly observed population of magnetic field fluctuations propagating at quasi-perpendicular angles to the global mean field B0, a population propagating at quasi-parallel angles are also observed with no local plasma instabilities identified. At low wavenumbers (kv_A/Omega_p <= 0.6 ) both components are present, and have similar powers, while at higher wavenumbers (kv_A/Omega_p> 0.6) only the perpendicular component can be identified. A statistical study of 52 intervals of solar wind finds that the turbulence is predominantly highly oblique to the magnetic field with perpendicular wavenumbers much greater than parallel wavenumbers, and propagates slowly in the plasma frame with most points having frequencies smaller than the proton gyrofrequency. Weak agreement is found that turbulence at the ion kinetic scales consists of kinetic Alfven waves and coherent structures advected with plasma bulk velocity plus some minor more compressible components. The results suggest that anti-sunward and sunward propagating magnetic fluctuations have similar nature in both the fast and slow solar wind. The fast wind was shown to have significantly more anti-sunward flux than sunward flux and the slow wind appears to be more balanced at ion kinetic scales. The fluctuated magnetic field and magnitude of the magnetic field are used to compute the power of incompressible and compressible turbulence for the fast solar wind. It is found that Taylor's frozen-in hypothesis may break down for compressible turbulence at the ion kinetic scales, suggesting that whistler waves may contribute to the compressible turbulence on the scales

  14. Modified Conditional Merging technique: a new method to estimate a rainfall field combining remote sensed data and raingauge observations

    NASA Astrophysics Data System (ADS)

    Pignone, Flavio; Rebora, Nicola; Silvestro, Francesco

    2015-04-01

    The estimation of the rainfall field, especially its spatial distribution and position, is a crucial task both for rainfall nowcasting and for modeling catchment response to rainfall. Some studies of literature about multisensor datafusion prove that combining data from different sensors (especially raingauges and radar) represents the best way to obtain an enhanced ad more reliable estimation of QPE and of the associated river discharge. Sinclair and Peagram (2004) have proposed the Conditional Merging (CM) technique, a merging algorithm which extract the information content from the observed data and use it within an interpolation method to obtain the rainfall maps. The raingauges provide a punctual measure of the observed "real" rainfall while the remote sensors (radar network or satellite constellation) supply rainfall estimation maps which give an idea of the spatial correlation structure of the observed field. In this work is studied an enhanced algorithm based on CM, called Modified Conditional Merging, which can be used in real-time to produce the optimal rainfall maps. The area of interest, where the CM has been applied, is Italy, where are both available a dense network of raingauge measurements (about 3000 stations) and a QPE estimated by the Italian Radar composite. The main innovation respect to classical CM is to estimate the structure of covariance and the length of spatial correlation λ, for every raingauge, directly from the cumulated radar rainfall fields. The advantages of this method is to estimate the local characteristic of the domain to obtain information at smaller scale, very useful for convective events. A cross-validation of the new method was done and several statistical scores were applied on the results. The validation on a large number of Italian past event along with its operational use are presented and discussed.

  15. Sterile insect technique and Mediterranean fruit fly (Diptera: Tephritidae): assessing the utility of aromatherapy in a Hawaiian coffee field.

    PubMed

    Shelly, Todd E; McInnis, Donald O; Rodd, Charles; Edu, James; Pahio, Elaine

    2007-04-01

    The sterile insect technique (SIT) is widely used in integrated programs against tephritid fruit fly pests, particularly the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Unfortunately, the mass-rearing procedures inherent to the SIT often lead to a reduction in the mating ability of the released males. One potential solution involves the prerelease exposure of males to particular attractants. In particular, exposure of male Mediterranean fruit flies to ginger, Zingiber officinale Roscoe, root oil (GRO) has been shown to increase mating success in laboratory and field cage trials. Here, we describe a field experiment that compares the level of egg sterility observed in two Hawaiian coffee, Coffea arabica L., plots, with GRO-exposed, sterile males released in one (treated) plot and nonexposed, sterile males released in the other (control) plot. Once per week in both plots over a 13-wk period, sterile males were released, trap captures were scored to estimate relative abundance of sterile and wild males, and coffee berries were collected and dissected in the laboratory to estimate the incidence of unhatched (sterile) eggs. Data on wild fly abundance and the natural rate of egg hatch also were collected in a remote area that received no sterile males. Despite that sterile:wild male ratios were significantly lower in the treated plot than in the control plot, the incidence of sterile eggs was significantly higher in the treated plot than in the control plot. Correspondingly, significantly higher values of Fried's competitiveness index (C) were found, on average, for treated than control sterile males. This study is the first to identify an association between the GRO "status" of sterile males and the incidence of egg sterility in the field and suggests that prerelease, GRO exposure may represent a simple and inexpensive means to increase the effectiveness of Mediterranean fruit fly SIT programs. PMID:17461047

  16. Boost in radiotherapy: external beam sunset, brachytherapy sunrise

    PubMed Central

    2009-01-01

    Radiobiological limitations for dose escalation in external radiotherapy are presented. Biological and clinical concept of brachytherapy boost to increase treatment efficacy is discussed, and different methods are compared. Oncentra Prostate 3D conformal real-time ultrasound-guided brachytherapy is presented as a solution for boost or sole therapy.

  17. The integrated analyses of digital field mapping techniques and traditional field methods: implications from the Burdur-Fethiye Shear Zone, SW Turkey as a case-study

    NASA Astrophysics Data System (ADS)

    Elitez, İrem; Yaltırak, Cenk; Zabcı, Cengiz; Şahin, Murat

    2015-04-01

    The precise geological mapping is one of the most important issues in geological studies. Documenting the spatial distribution of geological bodies and their contacts play a crucial role on interpreting the tectonic evolution of any region. Although the traditional field techniques are still accepted to be the most fundamental tools in construction of geological maps, we suggest that the integration of digital technologies to the classical methods significantly increases the resolution and the quality of such products. We simply follow the following steps in integration of the digital data with the traditional field observations. First, we create the digital elevation model (DEM) of the region of interest by interpolating the digital contours of 1:25000 scale topographic maps to 10 m of ground pixel resolution. The non-commercial Google Earth satellite imagery and geological maps of previous studies are draped over the interpolated DEMs in the second stage. The integration of all spatial data is done by using the market leading GIS software, ESRI ArcGIS. We make the preliminary interpretation of major structures as tectonic lineaments and stratigraphic contacts. These preliminary maps are controlled and precisely coordinated during the field studies by using mobile tablets and/or phablets with GPS receivers. The same devices are also used in measuring and recording the geologic structures of the study region. Finally, all digitally collected measurements and observations are added to the GIS database and we finalise our geological map with all available information. We applied this integrated method to map the Burdur-Fethiye Shear Zone (BFSZ) in the southwest Turkey. The BFSZ is an active sinistral 60-to-90 km-wide shear zone, which prolongs about 300 km-long between Suhut-Cay in the northeast and Köyceğiz Lake-Kalkan in the southwest on land. The numerous studies suggest contradictory models not only about the evolution but also about the fault geometry of this

  18. 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.

  19. 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

  20. Hydrodynamic approach to boost invariant free streaming

    NASA Astrophysics Data System (ADS)

    Calzetta, E.

    2015-08-01

    We consider a family of exact boost invariant solutions of the transport equation for free-streaming massless particles, where the one-particle distribution function is defined in terms of a function of a single variable. The evolution of second and third moments of the one-particle distribution function [the second moment being the energy momentum tensor (EMT) and the third moment the nonequilibrium current (NEC)] depends only on two moments of that function. Given those two moments, we show how to build a nonlinear hydrodynamic theory which reproduces the early time evolution of the EMT and the NEC. The structure of these theories may give insight on nonlinear hydrodynamic phenomena on short time scales.

  1. Boosting low-mass hadronic resonances

    NASA Astrophysics Data System (ADS)

    Shimmin, Chase; Whiteson, Daniel

    2016-09-01

    Searches for new hadronic resonances typically focus on high-mass spectra due to overwhelming QCD backgrounds and detector trigger rates. We present a study of searches for relatively low-mass hadronic resonances at the LHC in the case that the resonance is boosted by recoiling against a well-measured high-pT probe such as a muon, photon or jet. The hadronic decay of the resonance is then reconstructed either as a single large-radius jet or as a resolved pair of standard narrow-radius jets, balanced in transverse momentum to the probe. We show that the existing 2015 LHC data set of p p collisions with ∫L d t =4 fb-1 should already have powerful sensitivity to a generic Z' model which couples only to quarks, for Z' masses ranging from 20 - 500 GeV /c2 .

  2. 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.

  3. Boosting jet power in black hole spacetimes.

    PubMed

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

    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.

  4. Boosted X waves in nonlinear optical systems.

    PubMed

    Arévalo, 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.

  5. On the maximum regulation range in boost and buck-boost converters

    NASA Astrophysics Data System (ADS)

    Ninomiya, T.; Harada, K.; Nakahara, M.

    Two types of instability conditions in boost and buck-boost converters with a feedback loop are analyzed by means of the steady-state characteristic and dynamic small-signal modeling. Type I instability involves a drastic voltage drop, and in Type II instability, a limit-cycle oscillation arises and the output voltage oscillates at low frequencies. The maximum regulation range is derived analytically for the load variation and verified experimentally. For high feedback gain, it is determined by the Type II instability condition, whereas for low feedback gain, it is determined by the Type I instability condition. Type II instability can be suppressed by decreasing the reactor inductance or by increasing the capacitance of a smoothing capacitor. However, Type I instability is found to be independent of these values.

  6. Boosting for multi-graph classification.

    PubMed

    Wu, Jia; Pan, Shirui; Zhu, Xingquan; Cai, Zhihua

    2015-03-01

    In this paper, we formulate a novel graph-based learning problem, multi-graph classification (MGC), which aims to learn a classifier from a set of labeled bags each containing a number of graphs inside the bag. A bag is labeled positive, if at least one graph in the bag is positive, and negative otherwise. Such a multi-graph representation can be used for many real-world applications, such as webpage classification, where a webpage can be regarded as a bag with texts and images inside the webpage being represented as graphs. This problem is a generalization of multi-instance learning (MIL) but with vital differences, mainly because instances in MIL share a common feature space whereas no feature is available to represent graphs in a multi-graph bag. To solve the problem, we propose a boosting based multi-graph classification framework (bMGC). Given a set of labeled multi-graph bags, bMGC employs dynamic weight adjustment at both bag- and graph-levels to select one subgraph in each iteration as a weak classifier. In each iteration, bag and graph weights are adjusted such that an incorrectly classified bag will receive a higher weight because its predicted bag label conflicts to the genuine label, whereas an incorrectly classified graph will receive a lower weight value if the graph is in a positive bag (or a higher weight if the graph is in a negative bag). Accordingly, bMGC is able to differentiate graphs in positive and negative bags to derive effective classifiers to form a boosting model for MGC. Experiments and comparisons on real-world multi-graph learning tasks demonstrate the algorithm performance.

  7. Atmospheric measurements of hydroperoxides and aldehydes during field campaigns : new results due to improvement of measurements techniques

    NASA Astrophysics Data System (ADS)

    François, S.; Sowka, I.; Poulain, L.; Monod, A.; Wortham, H.

    2003-04-01

    Hydroperoxides and aldehydes are considered as atmospheric reservoirs of OH, HO_2 and RO_2 radicals and can reflect the oxidizing levels of the atmosphere. They are considered as important gas phase photo-oxidants present in the atmosphere. However, the atmospheric role of these compounds can vary from one species to another, therefore it is essential to investigate their measurement and speciation in the atmosphere. Atmospheric measurements were realized during two different field campaigns in the Marseilles area (France). Hydroperoxides were trapped in aqueous phase, with a glass coil and analyzed by HPLC/fluorescence detector with post column derivatization. Aldehydes were trapped in a liquid phase containing 2-4 DNPH, with a mist chamber and analyzed by HPLC/UV. The analytical techniques provided individual separation and quantification of seven hydroperoxides (hydrogen peroxide, hydroxymethyl hydroperoxide, bis(hydroxymethyl) peroxide, 1-hydroxyethyl hydroperoxide, methyl hydroperoxide, ethyl hydroperoxide and peroxyacetic acid) and eleven volatile aldehydes (formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde, crotonaldehyde, butyraldehyde, benzaldehyde, glyoxal, valeraldehyde and methylglyoxal). The first field campaign was part of the ESCOMPTE project (June 4th to July 16th 2001). During this campaign five different sampling sites, at low altitudes (<= 285 m), were investigated (maritime, urban, sub-industrial, biogenic and rural sites) and atmospheric measurements were realized during photochemical air pollution events. The second field campaign was part of the BOND project (July 2nd to July 14th 2002). Atmospheric measurements of hydroperoxides were carried out on one biogenic site, at altitude 690 m. The measurement system was improved allowing online sampling and analysis. During these field campaigns collection efficiencies were better than 96% for hydroperoxides, and from 78% to 96% for aldehydes. Detection limits were between 7,3× 10-3

  8. Maximum Power Point Tracking Controller for Thermoelectric Generators with Peak Gain Control of Boost DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Park, Jungyong; Kim, Shiho

    2012-06-01

    An analog maximum power point tracking (MPPT) circuit for a thermoelectric generator (TEG) is proposed. We show that the peak point of the voltage conversion gain of a boost DC-DC converter with an input voltage source having an internal resistor is the maximum power point of the TEG. The key characteristic of the proposed MPPT controller is that the duty ratio of the input clock pulse to the boost DC-DC converter shifts toward the maximum power point of the TEG by seeking the peak gain point of the boost DC-DC converters. The proposed MPPT technique provides a simple and useful analog MPPT solution, without employing digital microcontroller units.

  9. A comparison of rating and dating techniques to estimate the threat of soil erosion to archaeological monuments under agricultural fields

    NASA Astrophysics Data System (ADS)

    van Soest, Maud; Huisman, Hans; Schoorl, Jeroen; Reimann, Tony; Temme, Arnaud; Wallinga, Jakob; de Kort, Jan-Willem; van der Heiden, Menno; van Os, Bertil; van Egmond, Fenny; Ketteren, Michael

    2015-04-01

    For the protection of Dutch archaeological sites against degradation, the TOPsites project is investigating the rate, extent and mitigation of the most important processes involved. One of these processes is soil translocation or soil redistribution. For many Dutch archaeological sites the actual extent and rate of soil erosion is not yet known. In this study different techniques for dating and estimating rates have been compared on three archaeological sites on tilled fields with gentle slopes: (multi-temporal LiDar, profiles and spatial distribution of 137Cs, anthropogenic Pb, and 239+240Pu, and moreover OSL. In addition, the added value of the combination of several of these techniques together will be evaluated. Preliminary results show evidence for colluvium formation (deposition) on two of the sites. Lead contents in a buried soil on one of these sites suggest a subrecent to recent date. 137Cs profiles and spatial mapping, however, do not show clear evidence for recent erosion or re-deposition patterns. These first results suggest that in these agricultural settings with typical Dutch gentle slopes, erosion may only occur in rare, catastrophic, events with local high erosion and re-deposition rates instead of a more or less continuous process with lower rates. Consequently, the impact of ploughing might be limited to mixing of the plough layer, while the effect of damaging soil translocation, for these selected archaeological sites, seems less important. Forthcoming analysis and results of Pu and OSL will provide enough data for further discussion and possible falsification of these preliminary conclusions.

  10. Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene.

    PubMed

    Zheng, Chao; Huang, Le; Zhang, Hong; Sun, Zhongyue; Zhang, Zhiyong; Zhang, Guo-Jun

    2015-08-12

    Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO2 substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool.

  11. Total Skin Electron Therapy for Cutaneous T-Cell Lymphoma Using a Modern Dual-Field Rotational Technique

    SciTech Connect

    Heumann, Thatcher R.; Esiashvili, Natia; Parker, Sareeta; Switchenko, Jeffrey M.; Dhabbaan, Anees; Goodman, Michael; Lechowicz, Mary Jo; Flowers, Christopher R.; Khan, Mohammad K.

    2015-05-01

    Purpose: To report our experience with rotational total skin electron irradiation (RTSEI) in cutaneous T-cell lymphoma (CTCL), and to examine response by disease stage and race. Methods and Materials: We reviewed our outcomes for 68 CTCL patients who received RTSEI (≥30 Gy) from 2000 to 2013. Primary outcomes were complete clinical response (CCR), recurrence-free survival (RFS), and overall survival (OS). Using log–rank tests and Cox proportional hazards, OS and RFS were compared across tumor stages at time of RTSEI with further racial subgroup analysis. Results: Median age at diagnosis and at time of radiation was 52 and 56 years, respectively. Median follow-up was 5.1 years, 49% were African American, and 49% were female. At time of treatment, 18, 37, and 13 patients were T stage 2, 3, and 4, respectively. At 6 weeks after RTSEI, overall CCR was 82% (88%, 83%, and 69% for T2, T3, and T4, respectively). Median RFS was 11 months for all patients and 14, 10, and 12 months for stage T2, T3, and T4, respectively. Tumor stage was not associated with RFS or CCR. Maintenance therapy after RTSEI was associated with improved RFS in both crude and multivariable analysis, controlling for T stage. Median OS was 76 months (91 and 59 months for T3 and T4, respectively). With the exception of improved OS in African Americans compared with whites at stage T2, race was not associated with CCR, RFS, or OS. Conclusions: These results represent the largest RTSEI clinical outcomes study in the modern era using a dual-field rotational technique. Our observed response rates match or improve upon the standard set by previous outcome studies using conventional TSEI techniques, despite a large percentage of advanced CTCL lesions in our cohort. We found that clinical response after RTSEI did not seem to be affected by T stage or race.

  12. Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene.

    PubMed

    Zheng, Chao; Huang, Le; Zhang, Hong; Sun, Zhongyue; Zhang, Zhiyong; Zhang, Guo-Jun

    2015-08-12

    Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO2 substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool. PMID:26203889

  13. A High Efficiency Boost Converter with MPPT Scheme for Low Voltage Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Guan, Mingjie; Wang, Kunpeng; Zhu, Qingyuan; Liao, Wei-Hsin

    2016-11-01

    Using thermoelectric elements to harvest energy from heat has been of great interest during the last decade. This paper presents a direct current-direct current (DC-DC) boost converter with a maximum power point tracking (MPPT) scheme for low input voltage thermoelectric energy harvesting applications. Zero current switch technique is applied in the proposed MPPT scheme. Theoretical analysis on the converter circuits is explored to derive the equations for parameters needed in the design of the boost converter. Simulations and experiments are carried out to verify the theoretical analysis and equations. A prototype of the designed converter is built using discrete components and a low-power microcontroller. The results show that the designed converter can achieve a high efficiency at low input voltage. The experimental efficiency of the designed converter is compared with a commercial converter solution. It is shown that the designed converter has a higher efficiency than the commercial solution in the considered voltage range.

  14. Jet shapes for boosted jet two-prong decays from first-principles

    NASA Astrophysics Data System (ADS)

    Dasgupta, Mrinal; Schunk, Laís; Soyez, Gregory

    2016-04-01

    Several boosted jet techniques use jet shape variables to discriminate the multi-pronged signal from Quantum Chromodynamics backgrounds. In this paper, we provide a first-principles study of an important class of jet shapes all of which put a constraint on the subjet mass: the mass-drop parameter ( μ 2), the N -subjettiness ratio ( τ 21 ( β = 2) ) and energy correlation functions ( C 2 ( β = 2) or D 2 ( β = 2) . We provide analytic results both for QCD background jets as well as for signal processes. We further study the situation where cuts on these variables are applied recursively with Cambridge-Aachen de-clustering of the original jet. We also explore the effect of the choice of axis for N -subjettiness and jet de-clustering. Our results bring substantial new insight into the nature, gain and relative performance of each of these methods, which we expect will influence their future application for boosted object searches.

  15. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost

    PubMed Central

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%–3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  16. A High Efficiency Boost Converter with MPPT Scheme for Low Voltage Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Guan, Mingjie; Wang, Kunpeng; Zhu, Qingyuan; Liao, Wei-Hsin

    2016-07-01

    Using thermoelectric elements to harvest energy from heat has been of great interest during the last decade. This paper presents a direct current-direct current (DC-DC) boost converter with a maximum power point tracking (MPPT) scheme for low input voltage thermoelectric energy harvesting applications. Zero current switch technique is applied in the proposed MPPT scheme. Theoretical analysis on the converter circuits is explored to derive the equations for parameters needed in the design of the boost converter. Simulations and experiments are carried out to verify the theoretical analysis and equations. A prototype of the designed converter is built using discrete components and a low-power microcontroller. The results show that the designed converter can achieve a high efficiency at low input voltage. The experimental efficiency of the designed converter is compared with a commercial converter solution. It is shown that the designed converter has a higher efficiency than the commercial solution in the considered voltage range.

  17. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost.

    PubMed

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%-3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  18. Coupling machine learning methods with wavelet transforms and the bootstrap and boosting ensemble approaches for drought prediction

    NASA Astrophysics Data System (ADS)

    Belayneh, A.; Adamowski, J.; Khalil, B.; Quilty, J.

    2016-05-01

    This study explored the ability of coupled machine learning models and ensemble techniques to predict drought conditions in the Awash River Basin of Ethiopia. The potential of wavelet transforms coupled with the bootstrap and boosting ensemble techniques to develop reliable artificial neural network (ANN) and support vector regression (SVR) models was explored in this study for drought prediction. Wavelet analysis was used as a pre-processing tool and was shown to improve drought predictions. The Standardized Precipitation Index (SPI) (in this case SPI 3, SPI 12 and SPI 24) is a meteorological drought index that was forecasted using the aforementioned models and these SPI values represent short and long-term drought conditions. The performances of all models were compared using RMSE, MAE, and R2. The prediction results indicated that the use of the boosting ensemble technique consistently improved the correlation between observed and predicted SPIs. In addition, the use of wavelet analysis improved the prediction results of all models. Overall, the wavelet boosting ANN (WBS-ANN) and wavelet boosting SVR (WBS-SVR) models provided better prediction results compared to the other model types evaluated.

  19. Dynamics of multirate sampled data control systems. [for space shuttle boost vehicle

    NASA Technical Reports Server (NTRS)

    Naylor, J. R.; Hynes, R. J.; Molnar, D. O.

    1974-01-01

    The effect was investigated of the synthesis approach (single or multirate) on the machine requirements for a digital control system for the space shuttle boost vehicle. The study encompassed four major work areas: synthesis approach trades, machine requirements trades, design analysis requirements and multirate adaptive control techniques. The primary results are two multirate autopilot designs for the low Q and maximum Q flight conditions that exhibits equal or better performance than the analog and single rate system designs. Also, a preferred technique for analyzing and synthesizing multirate digital control systems is included.

  20. Comparison between eddy covariance and automatic chamber techniques for measuring net ecosystem exchange of carbon dioxide in cotton and wheat fields

    NASA Astrophysics Data System (ADS)

    Wang, K.; Liu, C.; Zheng, X.; Pihlatie, M.; Li, B.; Haapanala, S.; Vesala, T.; Liu, H.; Wang, Y.; Liu, G.; Hu, F.

    2013-11-01

    Static and transparent automatic chamber (AC) technique is a necessary choice for measuring net ecosystem exchange (NEE) of carbon dioxide (CO2) in circumstances where eddy covariance (EC) technique is not applicable. However, a comparison of the two techniques for measurements on croplands has seldom been undertaken. We carried out NEE observations in a cotton field (for one year) and a winter wheat field (for one cropping season) using both AC and EC techniques, to (a) compare the NEE fluxes measured using each technique, and (b) test the NEE measurement performance of an automatic chamber system (AMEG), which was designed for simultaneous flux measurements of multiple gases. The half-hourly NEE fluxes measured with the two techniques were in approximate agreement, with the AC fluxes being 0.78 (cotton) and 1.06 (wheat) times the size of the EC fluxes. When integrated to daily timescale, the fluxes of the two techniques were in better agreement, showing an average ratio of 0.94 and 1.00 for the cotton and wheat, respectively. During the periods with comparable field conditions and normal performance of both instruments, the cumulative NEE fluxes revealed small differences between the two techniques (-9.0% ~ 7%, with a mean of 0.1%). The measurements resulted in an annual cumulative NEE of -40 g C m-2 yr-1 (EC) and -42 g C m-2 yr-1 (AC) in the cotton field, and a seasonal cumulative NEE of -251 g C m-2 (EC) and -205 g C m-2 (AC) in the wheat field. Our results indicate that, for cropland populated by short plants, the AMEG system and the data processing procedures applied in this study are able to provide NEE estimates comparable to those from EC measurements.

  1. Compact sensor combining digital speckle pattern interferometry and the hole-drilling technique to measure nonuniform residual stress fields

    NASA Astrophysics Data System (ADS)

    Viotti, Matías R.; Albertazzi, Armando

    2013-10-01

    A portable device to essentially measure residual stress fields outside an optical bench is presented. This system combines the hole-drilling technique with digital speckle pattern interferometry. A novel feature of this device is its high degree of compaction since only one base supports simultaneously the measurement module and the hole-drilling device. A new version of the American society for testing and materials standard E837 for the measurement of residual stresses has been improved including a computation method for nonuniform residual stresses. According to this standard, a hole with a maximum depth of 1.0 mm should be introduced into the material to assess the stress distribution along the hole's depth. The discretization of the stress distribution is performed in 20 equal steps of 0.05 mm, getting the deformations generated for stress relief in every drilling step. A description of the compact device showing the solution for a fast and easy interchanging process between modules is also presented. The proposed system was compared with a traditional method using strain gages, and a good agreement was shown between stress distributions measured with both methods. Finally, the portable device was used to evaluate the residual stress distribution in a sample with a rod welded by friction hydro pillar processing.

  2. The Applications of Decision-Level Data Fusion Techniques in the Field of Multiuser Detection for DS-UWB Systems

    PubMed Central

    Gu, Yebo; Yang, Minglei; Shi, Zhenguo; Wu, Zhilu

    2015-01-01

    In this paper, the decision-level data fusion techniques are extended to the multiuser detection (MUD) field. Then two novel MUD algorithms, that is the chairman arbitrating decision-level fusion criterion (CA-DFC) based MUD algorithm and the veto logic decision-level fusion criterion (VL-DFC) based MUD algorithm, are proposed for DS-UWB communication systems. In CA-DFC based method, the chairman can make his arbitration among the preliminary decisions from sub-optimal detectors by his own rule. In the VL-DFC based method, the undetermined bits in these preliminary decisions are considered to construct a simplified solution space, and then the chairman can make his final decision within this space. Simulation results demonstrate that the performances of CA-DFC and VL-DFC based MUD algorithms are superior to those of other sub-optimal MUD algorithms, and even close to that of OMD. Moreover, both of these proposed algorithms have lower computational complexity than OMD, which reveals their efficiency. Compared with CA-DFC, VL-DFC based algorithm achieves a little improvement in its performance, at the cost of the increment in its computational complexity. Thus, they can be applied to different practical situations. PMID:26404273

  3. Electromagnetic self-consistent field initialization and fluid advance techniques for hybrid-kinetic PWFA code Architect

    NASA Astrophysics Data System (ADS)

    Massimo, F.; Marocchino, A.; Rossi, A. R.

    2016-09-01

    The realization of Plasma Wakefield Acceleration experiments with high quality of the accelerated bunches requires an increasing number of numerical simulations to perform first-order assessments for the experimental design and online-analysis of the experimental results. Particle in Cell codes are the state-of-the-art tools to study the beam-plasma interaction mechanism, but due to their requirements in terms of number of cores and computational time makes them unsuitable for quick parametric scans. Considerable interest has been shown thus in methods which reduce the computational time needed for the simulation of plasma acceleration. Such methods include the use of hybrid kinetic-fluid models, which treat the relativistic bunches as in a PIC code and the background plasma electrons as a fluid. A technique to properly initialize the bunch electromagnetic fields in the time explicit hybrid kinetic-fluid code Architect is presented, as well the implementation of the Flux Corrected Transport scheme for the fluid equations integrated in the code.

  4. Inspection of the Space Shuttle External Tank SOFI Using Near-Field and Focused Millimeter Wave Nondestructive Testing Techniques

    NASA Technical Reports Server (NTRS)

    Kharkovsky, S.; Hepburn, F.; Walker, J.; Zoughi, R.

    2005-01-01

    The Space Shuttle Columbia's catastrophic failure has been attributed to a piece of external tank SOFI (Spray On Foam Insulation) striking the left wing of the orbiter causing significant damage to some of the reinforced carbon/carbon leading edge wing panels. Subsequently, several nondestructive testing (NDT) techniques have been considered for inspecting the external tank. One such method involves using millimeter waves which have been shown to easily penetrate through the foam and provide high resolution images of its interior structures. This paper presents the results of inspecting three different SOFI covered panels by reflectometers at millimeter wave frequencies, specifically at 100 GHz. Each panel was fitted with various embedded anomalies/inserts representing voids and unbonds of diferent shapes, sizes and locations within each panel. In conjunction with these reJqectome&rs, radiators including a focused lens antenna and a small horn antenna were used. The focused lens antenna provided for a footprint diameter of approximately 1.25 cm (0.5") at 25.4 cm (10") away from the lens surface. The horn antenna was primarily operated in its near-field for obtaining relatively high resolution images. These images were produced using 2 0 scanning mechanisms. Discussions of the difference between the capabilities of these two types of antennas (radiators) for the purpose of inspecting the SOFI as it relates to the produced images are also presented.

  5. Ultra-thin resistive switching oxide layers self-assembled by field-induced oxygen migration (FIOM) technique.

    PubMed

    Lee, Sangik; Hwang, Inrok; Oh, Sungtaek; Hong, Sahwan; Kim, Yeonsoo; Nam, Yoonseung; Lee, Keundong; Yoon, Chansoo; Kim, Wondong; Park, Bae Ho

    2014-11-03

    High-performance ultra-thin oxide layers are required for various next-generation electronic and optical devices. In particular, ultra-thin resistive switching (RS) oxide layers are expected to become fundamental building blocks of three-dimensional high-density non-volatile memory devices. Until now, special deposition techniques have been introduced for realization of high-quality ultra-thin oxide layers. Here, we report that ultra-thin oxide layers with reliable RS behavior can be self-assembled by field-induced oxygen migration (FIOM) at the interface of an oxide-conductor/oxide-insulator or oxide-conductor/metal. The formation via FIOM of an ultra-thin oxide layer with a thickness of approximately 2-5 nm and 2.5% excess oxygen content is demonstrated using cross-sectional transmission electron microscopy and secondary ion mass spectroscopy depth profile. The observed RS behavior, such as the polarity dependent forming process, can be attributed to the formation of an ultra-thin oxide layer. In general, as oxygen ions are mobile in many oxide-conductors, FIOM can be used for the formation of ultra-thin oxide layers with desired properties at the interfaces or surfaces of oxide-conductors in high-performance oxide-based devices.

  6. A new submodelling technique for multi-scale finite element computation of electromagnetic fields: Application in bioelectromagnetism

    NASA Astrophysics Data System (ADS)

    Aristovich, K. Y.; Khan, S. H.

    2010-07-01

    Complex multi-scale Finite Element (FE) analyses always involve high number of elements and therefore require very long time of computations. This is caused by the fact, that considered effects on smaller scales have greater influences on the whole model and larger scales. Thus, mesh density should be as high as required by the smallest scale factor. New submodelling routine has been developed to sufficiently decrease the time of computation without loss of accuracy for the whole solution. The presented approach allows manipulation of different mesh sizes on different scales and, therefore total optimization of mesh density on each scale and transfer results automatically between the meshes corresponding to respective scales of the whole model. Unlike classical submodelling routine, the new technique operates with not only transfer of boundary conditions but also with volume results and transfer of forces (current density load in case of electromagnetism), which allows the solution of full Maxwell's equations in FE space. The approach was successfully implemented for electromagnetic solution in the forward problem of Magnetic Field Tomography (MFT) based on Magnetoencephalography (MEG), where the scale of one neuron was considered as the smallest and the scale of whole-brain model as the largest. The time of computation was reduced about 100 times, with the initial requirements of direct computations without submodelling routine of 10 million elements.

  7. A least-squares inversion technique for identification of a point release: Application to Fusion Field Trials 2007

    NASA Astrophysics Data System (ADS)

    Singh, Sarvesh Kumar; Rani, Raj

    2014-08-01

    Identification of a point release is a parametric estimation problem associated with the estimation of its parameters namely, location and strength. A least-squares inversion algorithm, free from initial guess of release parameters, is utilized here for the source identification in eleven trials of single continuous point releases conducted during Fusion Field Trials 2007. The source locations are retrieved within an average error of 23 m from their true locations. The maximum and minimum errors in the retrieval of the source location are obtained as 57.3 m and 3 m respectively. The source strength is retrieved within a factor of 1.6 in all the trials. The sensitivity of the source estimation is analysed with respect to (i) variation of grid sizes in discretized space, (ii) inclusion of zero measurements and (iii) addition of new measurements. Posterior uncertainty is mentioned in terms of variance of the source parameters, approximated by using the Hessian of the cost function. In addition, an attempt is made to obtain the minimum number of measurements for a successful source inversion. The study explores the future applicability of this least-squares inversion technique for point source identification.

  8. The application of the RELIEF technique for velocity field measurements in the ASTF C1 test cell

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Aeropropulsion Systems Test Facility (ASTF) C1 Test Cell is to be configured for propulsion tests of National Aerospace Plane (NASP) engines over flight Mach number conditions ranging from 0.5 to 3.8. This facility is capable of continuously generating a 5 ft. x 5 ft. square free air jet flow field at a local Mach number up to 3.32 with a density of between 0.134 and 0.048 amagat and a static temperature of 257 K or less. The potential of the Raman Excitation + Laser Induced Electronic Fluorescence (RELIEF) velocity measurement technique for measuring the three dimensional velocity profile across the exit plane of this jet and the entrance plane to the test engine under these conditions is examined. Velocity measurements must be done to an accuracy of better than 1 percent. Flow direction must be measured to better than 1 deg for inlet performance evaluation. Measurements to these specifications need to be done with a grid spacing of approximately 1/100th of the cross sectional dimension of the free jet exit in a time not greater than 30 seconds.

  9. Facile One-Step Strategy for Highly Boosted Microbial Extracellular Electron Transfer of the Genus Shewanella.

    PubMed

    Wang, Yuan; Lv, Meiling; Meng, Qingan; Ding, Chunmei; Jiang, Lei; Liu, Huan

    2016-06-28

    High performance of bacterial extracellular electron transfer (EET) is essentially important for its practical applications in versatile bioelectric fields. We developed a facile one-step approach to dramatically boost the bacterial EET activity 75-fold by exogenous addition of ethylenediamine tetraacetic acid disodium salt (EDTA-2Na, 1 mM) into the electrochemical cells, where the anodic process of microbial EET was monitored. We propose that EDTA-2Na enables both the alternation of the local environment around the c-type cytochromes located on the outer membrane channels (OMCs), which therefore changes the redox behavior of OMCs in mediating the EET process, and the formation of densely packed biofilm that can further facilitate the EET process. As a synergistic effect, the highly boosted bacterial EET activity was achieved. The method shows good generality for versatile bioelectrical bacteria. We envision that the method is also applicable for constructing various bioelectric devices. PMID:27196945

  10. Ambient in-situ immersion freezing measurements - findings from the ZAMBIS 2014 field campaign for three ice nucleation techniques

    NASA Astrophysics Data System (ADS)

    Kohn, Monika; Atkinson, James D.; Lohmann, Ulrike; Kanji, Zamin A.

    2015-04-01

    To estimate the influence of clouds on the Earth's radiation budget, it is crucial to understand cloud formation processes in the atmosphere. A key process, which significantly affects cloud microphysical properties and the initiation of precipitation thus contributing to the hydrological cycle, is the prevailing type of ice nucleation mechanism. In mixed-phase clouds immersion freezing is the dominant ice crystal forming mechanism, whereby ice nucleating particles (INP) first act as cloud condensation nuclei (CCN) and are activated to cloud droplets followed by freezing upon supercooling. There are a number of experimental methods and techniques to investigate the ice nucleating ability in the immersion mode, however most techniques are offline for field sampling or only suitable for laboratory measurements. In-situ atmospheric studies are needed to understand the ice formation processes of 'real world' particles. Laboratory experiments simulate conditions of atmospheric processes like ageing or coating but are still idealized. Our method is able to measure ambient in-situ immersion freezing on single immersed aerosol particles. The instrumental setup consists of the recently developed portable immersion mode cooling chamber (PIMCA) as a vertical extension to the portable ice nucleation chamber (PINC, [1]), where the frozen fraction of activated aerosol particles are detected by the ice optical depolarization detector (IODE, [2]). Two additional immersion freezing techniques based on a droplet freezing array [3,4] are used to sample ambient aerosol particles either in a suspension (fraction larger ~0.6 μm) or on PM10-filters to compare different ice nucleation techniques. Here, we present ambient in-situ measurements at an urban forest site in Zurich, Switzerland held during the Zurich ambient immersion freezing study (ZAMBIS) in spring 2014. We investigated the ice nucleating ability of natural atmospheric aerosol with the PIMCA/PINC immersion freezing setup as

  11. ArborZ: PHOTOMETRIC REDSHIFTS USING BOOSTED DECISION TREES

    SciTech Connect

    Gerdes, David W.; Sypniewski, Adam J.; McKay, Timothy A.; Hao, Jiangang; Weis, Matthew R.; Wechsler, Risa H.; Busha, Michael T.

    2010-06-01

    Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area imaging surveys. In this paper, we introduce a photometric redshift algorithm, ArborZ, based on the machine-learning technique of boosted decision trees. We study the algorithm using galaxies from the Sloan Digital Sky Survey (SDSS) and from mock catalogs intended to simulate both the SDSS and the upcoming Dark Energy Survey. We show that it improves upon the performance of existing algorithms. Moreover, the method naturally leads to the reconstruction of a full probability density function (PDF) for the photometric redshift of each galaxy, not merely a single 'best estimate' and error, and also provides a photo-z quality figure of merit for each galaxy that can be used to reject outliers. We show that the stacked PDFs yield a more accurate reconstruction of the redshift distribution N(z). We discuss limitations of the current algorithm and ideas for future work.

  12. Heterodyning Time Resolution Boosting for Velocimetry and Reflectivity Measurements

    SciTech Connect

    Erskine, D J

    2004-08-02

    A theoretical technique is described for boosting the temporal resolving power by several times, of detectors such as streak cameras in experiments that measure light reflected from or transmitted through a target, including velocity interferometer (VISAR) measurements. This is a means of effectively increasing the number of resolvable time bins in a streak camera record past the limit imposed by input slit width and blur on the output phosphor screen. The illumination intensity is modulated sinusoidally at a frequency similar to the limiting time response of the detector. A heterodyning effect beats the high frequency science signal down a lower frequency beat signal, which is recorded together with the conventional science signal. Using 3 separate illuminating channels having different phases, the beat term is separated algebraically from the conventional signal. By numerically reversing the heterodyning, and combining with the ordinary signal, the science signal can be reconstructed to better effective time resolution than the detector used alone. The effective time resolution can be approximately halved for a single modulation frequency, and further decreased inversely proportional to the number of independent modulation frequencies employed.

  13. Stress analysis and tectonic trends of southern Sinai Peninsula, using potential field data analysis and anisotropy technique

    NASA Astrophysics Data System (ADS)

    Saleh, Salah; Saleh, Ahmed

    2012-09-01

    The aim of the present work is to evaluate the stress direction and the tectonic trends of the study area using magnetic anisotropy and potential field data interpretations (Bouguer and aeromagnetic). The specific objective of the gravity and aeromagnetic interpretation is to establish the trend and depth of the structural configuration of the basement rocks. Horizontal gradient techniques could to delineate directions of deep sources and enabled tracing several faults, lineaments and tectonic boundaries of basement rocks. The trend analysis shows N40°-50°W, N10°-20°W and N10°-20°E which may be related to the Gulf of Suez, Red Sea and Gulf of Aqaba stresses. However, Euler Deconvolution technique was applied using the aeromagnetic data to provide reliable information about penetrated source depth (100 m and ˜10.0 km) and trends of the subsurface sources (principally in NW and NE directions). Moreover, representative 72 oriented rock samples have been collected from seven sites in the study area. The rock magnetic properties and magnetic anisotropy analysis have been determined for all the studied samples. The interpretation clearly defined magnetic lineation at all sites and anisotropy of magnetic susceptibility (AMS) parameters. The stress direction of the studied area has been evaluated using magnetic anisotropy and geophysical analysis. Generally the estimated geophysical data analysis (Bouguer and aeromagnetic) are well consistent with the AMS interpretations of this study. The results indicated that the directions of predominant faults and foliations are NW-SE (related to the Gulf of Suez and Red Sea rifting) which indicate that the main stress and tectonic trend is NE-SW, which is more predominant in southern Sinai region. Moreover, it is clear that, the studied area was affected also by less predominant sources trended in NE-SW direction, which related to the tectonic activity of Gulf of Aqaba. The least predominant is north 40°-50° east that is

  14. Stress analysis and tectonic trends of southern Sinai Peninsula, using potential field data analysis and anisotropy technique

    NASA Astrophysics Data System (ADS)

    Saleh, Salah; Saleh, Ahmed

    2012-09-01

    The aim of the present work is to evaluate the stress direction and the tectonic trends of the study area using magnetic anisotropy and potential field data interpretations (Bouguer and aeromagnetic). The specific objective of the gravity and aeromagnetic interpretation is to establish the trend and depth of the structural configuration of the basement rocks. Horizontal gradient techniques could to delineate directions of deep sources and enabled tracing several faults, lineaments and tectonic boundaries of basement rocks. The trend analysis shows N40°-50°W, N10°-20°W and N10°-20°E which may be related to the Gulf of Suez, Red Sea and Gulf of Aqaba stresses. However, Euler Deconvolution technique was applied using the aeromagnetic data to provide reliable information about penetrated source depth (100 m and ˜10.0 km) and trends of the subsurface sources (principally in NW and NE directions). Moreover, representative 72 oriented rock samples have been collected from seven sites in the study area. The rock magnetic properties and magnetic anisotropy analysis have been determined for all the studied samples. The interpretation clearly defined magnetic lineation at all sites and anisotropy of magnetic susceptibility ( AMS) parameters. The stress direction of the studied area has been evaluated using magnetic anisotropy and geophysical analysis. Generally the estimated geophysical data analysis (Bouguer and aeromagnetic) are well consistent with the AMS interpretations of this study. The results indicated that the directions of predominant faults and foliations are NW-SE (related to the Gulf of Suez and Red Sea rifting) which indicate that the main stress and tectonic trend is NE-SW, which is more predominant in southern Sinai region. Moreover, it is clear that, the studied area was affected also by less predominant sources trended in NE-SW direction, which related to the tectonic activity of Gulf of Aqaba. The least predominant is north 40°-50° east that is

  15. Studying the spatial variability of Cr in agricultural field using both particle induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA) technique

    NASA Astrophysics Data System (ADS)

    Cruvinel, Paulo E.; Crestana, Sílvio; Artaxo, Paulo; Martins, JoséV.; Armelin, Maria JoséA.

    1996-04-01

    In the field of soil physics, a technique which permits a non-destructive, accurate and fast elemental analysis with a minimum of sample preparation effort is often desired. Although trace elements are minor components of the solid phase, they play an important role in soil fertility. Cr is of nutritional importance because it is a required element in human and animal nutrition. The immobility of Cr may be responsible for an inadequate Cr supply to plants. This work not only demonstrates the suitability of PIXE as a fast and non-destructive technique, useful to measure Cr content in soil samples, but also outlines a study of spatial variability of that element in agricultural field. To demonstrate the capability of the method soil samples were collected in a 5000 m 2 agricultural field. The soil samples were analyzed using both PIXE and INAA techniques. Besides, a Fourier interpolation technique was used to verify the distribution of Cr along of the sampled field. INAA was carried out by means of the γ-ray emitted by 51Cr(320 keV). Results show that there is a good linear relationship between the elemental concentration of Cr obtained using those techniques, i.e. a correlation coefficient of r2 = 0.82 was achieved.

  16. SU-E-T-272: Radiation Damage Comparison Between Intensity Modulated Radiotherapy and Field-In-Field Technique in Breast Cancer Treatments

    SciTech Connect

    Ai, H; Zhang, H

    2014-06-01

    Purpose: To compare normal tissue complications between IMRT and FIF treatment in breast cancer. Methods: 16 patients treated with IMRT plan and 20 patients treated with FIF plan were evaluated in this study. Both kinds of plans were generated using Eclipse treatment planning system by dosimetrist following clinical radiotherapy treatment guidelines. The plans were reviewed and approved by radiation oncologist. The average survival fraction (SF) for three different normal tissue cells of each concerned structure can be calculated from differential dose volume histogram (DVH) using linear quadratic model. The three types of normal tissues include radiosensitive, moderately radiosensitive and radio-resistant that represents 70%, 50% and 30% survival fractions, respectively, for a 2-Gy open field. Equivalent uniform doses (EUD) for corresponding normal tissues of each structure were calculated. Results: The EUDs of the lungs, heart, healthy breast and spinal cord with both IMRT and FIF treatments were calculated. Considering the average value of all IMRT plans, the lung of treated side absorbed 16.0% of dosage prescribed to the tumor if the radiosensitivity of the lung is similar to the radiosensitive cell line. For moderately radiosensitive and radio-resistant lung tissue, the average EUDs can be 18.9% and 22.4% of prescription. In contrast, patients treated with FIF plans were delivered 6.0%, 7.5% and 10.3% of prescribed dose for radiosensitive, moderately radiosensitive and radio-resistant lung tissue, respectively. Comparing heart EUDs between IMRT and FIF plans, average absorbed doses in IMRT treatment were 7.7%, 8.7% and 9.7% of prescription for three types of heart normal tissue cell lines while FIF treatments delivered only 1.3%, 1.5% and 1.6% of prescription dose. For the other organs, the results were similar. Conclusion: The results indicated that breast cancer treatment using IMRT technique had more normal tissue damage than FIF treatment. FIF demonstrated

  17. Exploiting tRNAs to Boost Virulence.

    PubMed

    Albers, Suki; Czech, Andreas

    2016-01-01

    Transfer RNAs (tRNAs) are powerful small RNA entities that are used to translate nucleotide language of genes into the amino acid language of proteins. Their near-uniform length and tertiary structure as well as their high nucleotide similarity and post-transcriptional modifications have made it difficult to characterize individual species quantitatively. However, due to the central role of the tRNA pool in protein biosynthesis as well as newly emerging roles played by tRNAs, their quantitative assessment yields important information, particularly relevant for virus research. Viruses which depend on the host protein expression machinery have evolved various strategies to optimize tRNA usage-either by adapting to the host codon usage or encoding their own tRNAs. Additionally, several viruses bear tRNA-like elements (TLE) in the 5'- and 3'-UTR of their mRNAs. There are different hypotheses concerning the manner in which such structures boost viral protein expression. Furthermore, retroviruses use special tRNAs for packaging and initiating reverse transcription of their genetic material. Since there is a strong specificity of different viruses towards certain tRNAs, different strategies for recruitment are employed. Interestingly, modifications on tRNAs strongly impact their functionality in viruses. Here, we review those intersection points between virus and tRNA research and describe methods for assessing the tRNA pool in terms of concentration, aminoacylation and modification. PMID:26797637

  18. Exploiting tRNAs to Boost Virulence

    PubMed Central

    Albers, Suki; Czech, Andreas

    2016-01-01

    Transfer RNAs (tRNAs) are powerful small RNA entities that are used to translate nucleotide language of genes into the amino acid language of proteins. Their near-uniform length and tertiary structure as well as their high nucleotide similarity and post-transcriptional modifications have made it difficult to characterize individual species quantitatively. However, due to the central role of the tRNA pool in protein biosynthesis as well as newly emerging roles played by tRNAs, their quantitative assessment yields important information, particularly relevant for virus research. Viruses which depend on the host protein expression machinery have evolved various strategies to optimize tRNA usage—either by adapting to the host codon usage or encoding their own tRNAs. Additionally, several viruses bear tRNA-like elements (TLE) in the 5′- and 3′-UTR of their mRNAs. There are different hypotheses concerning the manner in which such structures boost viral protein expression. Furthermore, retroviruses use special tRNAs for packaging and initiating reverse transcription of their genetic material. Since there is a strong specificity of different viruses towards certain tRNAs, different strategies for recruitment are employed. Interestingly, modifications on tRNAs strongly impact their functionality in viruses. Here, we review those intersection points between virus and tRNA research and describe methods for assessing the tRNA pool in terms of concentration, aminoacylation and modification. PMID:26797637

  19. Refiners boost crude capacity; Petrochemical production up

    SciTech Connect

    Corbett, R.A.

    1988-03-21

    Continuing demand strength in refined products and petrochemical markets caused refiners to boost crude-charging capacity slightly again last year, and petrochemical producers to increase production worldwide. Product demand strength is, in large part, due to stable product prices resulting from a stabilization of crude oil prices. Crude prices strengthened somewhat in 1987. That, coupled with fierce product competition, unfortunately drove refining margins negative in many regions of the U.S. during the last half of 1987. But with continued strong demand for gasoline, and an increased demand for higher octane gasoline, margins could turn positive by 1989 and remain so for a few years. U.S. refiners also had to have facilities in place to meet the final requirements of the U.S. Environmental Protection Agency's lead phase-down rules on Jan. 1, 1988. In petrochemicals, plastics demand dept basic petrochemical plants at good utilization levels worldwide. U.S. production of basics such as ethylene and propylene showed solid increases. Many of the derivatives of the basic petrochemical products also showed good production gains. Increased petrochemical production and high plant utilization rates didn't spur plant construction projects, however. Worldwide petrochemical plant projects declined slightly from 1986 figures.

  20. Every Day in The Womb Boosts Babies' Brain Development

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_161778.html Every Day in the Womb Boosts Babies' Brain Development: Study ... What this study shows us is that every day and every week of in utero development is ...