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Sample records for non-orthogonal fixed beam

  1. The non-orthogonal fixed beam arrangement for the second proton therapy facility at the National Accelerator Center

    NASA Astrophysics Data System (ADS)

    Schreuder, A. N.; Jones, D. T. L.; Conradie, J. L.; Fourie, D. T.; Botha, A. H.; Müller, A.; Smit, H. A.; O'Ryan, A.; Vernimmen, F. J. A.; Wilson, J.; Stannard, C. E.

    1999-06-01

    The medical user group at the National Accelerator Center (NAC) is currently unable to treat all eligible patients with high energy protons. Developing a second proton treatment room is desirable since the 200 MeV proton beam from the NAC separated sector cyclotron is currently under-utilized during proton therapy sessions. During the patient positioning phase in one treatment room, the beam could be used for therapy in a second room. The second proton therapy treatment room at the NAC will be equipped with two non-orthogonal beam lines, one horizontal and one at 30 degrees to the vertical. The two beams will have a common isocentre. This beam arrangement together with a versatile patient positioning system (commercial robot arm) will provide the radiation oncologist with a diversity of possible beam arrangements and offers a reasonable cost-effective alternative to an isocentric gantry.

  2. The non-orthogonal fixed beam arrangement for the second proton therapy facility at the National Accelerator Center

    SciTech Connect

    Schreuder, A. N.; Jones, D. T. L.; Conradie, J. L.; Fourie, D. T.; Botha, A. H.; Mueller, A.; Smit, H. A.; O'Ryan, A.; Vernimmen, F. J. A.; Wilson, J.; Stannard, C. E.

    1999-06-10

    The medical user group at the National Accelerator Center (NAC) is currently unable to treat all eligible patients with high energy protons. Developing a second proton treatment room is desirable since the 200 MeV proton beam from the NAC separated sector cyclotron is currently under-utilized during proton therapy sessions. During the patient positioning phase in one treatment room, the beam could be used for therapy in a second room. The second proton therapy treatment room at the NAC will be equipped with two non-orthogonal beam lines, one horizontal and one at 30 degrees to the vertical. The two beams will have a common isocentre. This beam arrangement together with a versatile patient positioning system (commercial robot arm) will provide the radiation oncologist with a diversity of possible beam arrangements and offers a reasonable cost-effective alternative to an isocentric gantry.

  3. The spatial-matched-filter beam pattern of a biaxial non-orthogonal velocity sensor

    NASA Astrophysics Data System (ADS)

    Lee, Charles Hung; Lee, Hye Rin Lindsay; Wong, Kainam Thomas; Razo, Mario

    2016-04-01

    This work derives the "spatial matched filter" beam pattern of a "u-u probe", which comprises two uniaxial velocity sensors, that are identical, collocated, and oriented supposedly in orthogonality. This non-orthogonality may be unrealized in real-world hardware implementation, and would consequentially cause a beamformer to have a systemic pointing error, which is derived analytically here in this paper. Other than this point error, this paper's analysis shows that the beam shape would otherwise be unchanged.

  4. 41. Fixed Span, Floor Beam 1, showing the cantilever; looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. Fixed Span, Floor Beam 1, showing the cantilever; looking N. (The splice between the original beam and the 1960 extension (widening) is between the two stringers to the left of the bottom chord tension members). - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA

  5. Experimental Study on Nonlinear Vibrations of Fixed-Fixed Curved Beams

    NASA Astrophysics Data System (ADS)

    Kumar, Ajay; Patel, B. P.

    2016-07-01

    Nonlinear dynamic behavior of fixed-fixed shallow and deep curved beams is studied experimentally using non-contact type of electromagnetic shaker and acceleration measurements. The frequency response obtained from acceleration measurements is found to be in fairly good agreement with the computational response. The travellingwave phenomenon along with participation of higher harmonics and softening nonlinearity are observed. The experimental results on the internal resonance of curved beams due to direct excitation of anti-symmetric mode are reported for the first time. The deep curved beam depicts chaotic response at higher excitation amplitude.

  6. 42. Fixed Span; General View of the Floor Beam, Stringer, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. Fixed Span; General View of the Floor Beam, Stringer, & Lateral Bracing System; looking S. (from near to far: 6L & R, 5L & R, 4 L & R). - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA

  7. Heat welding of non-orthogonal X-junction of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yang, Xueming; Han, Zhonghe; Li, Yonghua; Chen, Dongci; Zhang, Pu; To, Albert C.

    2012-09-01

    Though X-junctions of single-walled carbon nanotubes (SWCNTs) have been intensively studied, studies concerning non-orthogonal X-junctions are still very rare. In this paper, the heat welding of defect-free non-orthogonal X-junctions with different crossed angles are investigated by molecular dynamics simulations. The difference between the heat welding of non-orthogonal and orthogonal X-junctions is described, and the angle effect on the configuration and stability of the heat welded non-orthogonal X-junctions is discussed. Compared with the orthogonal X-junction, two crossed SWCNTs with a smaller non-orthogonal angle are easier to join by heat welding, and this may be an important reason why the large tubes are difficult to join, whereas large nanotube bundles are easier to observe in experiments.

  8. Laser Welding of Alumina Ceramic Substrates with Two Fixed Beams

    NASA Astrophysics Data System (ADS)

    Sedore, Blake William Clark

    Laser welding was investigated as a potential joining technology for alumina ceramic substrates. The objective of this study was to develop a method to preheat the ceramic using a single defocused laser beam prior to welding. Engineering ceramics are employed in a variety of systems and environments due to their unique properties. Joining technologies must be developed to facilitate the manufacture of complex or large ceramic components. Laser welding is advantageous as it forms joints rapidly, and does not introduce intermediate materials to form the bond, which can have deleterious effects. The Laser Machining System (LMS) at Queen's University was adapted for this study. A defocused far-infrared (FIR) laser beam was positioned to overlay a focused near-infrared (NIR) laser beam; the defocused FIR beam preheated the ceramic substrate and the focused NIR beam formed the weld. A finite element model was developed in COMSOL MultiPhysics to simulate the preheating processes and to develop a preheating protocol. The protocol was implemented using the FIR beam and adjusted to achieve preheating temperatures of 1450, 1525, and 1600°C. Welds were performed on 1 mm thick alumina plates using the preheating protocols and NIR beam powers of 25, 50, and 75 W. Weld speed was held constant throughout the study at 0.5 mm/s. The preheating protocols were successful at achieving near-constant preheating temperatures, with standard deviations below 32 degrees. Partially penetrating welds were formed with the NIR beam at 25 W, and fully penetrating welds at 50 and 75 W. Large pores were present in the 25 W and 50 W welds. Minimal porosity was observed in the welds formed at 75 W. All of the welded plates experienced a transverse fracture that extended perpendicular to weld, and a longitudinal fracture extending parallel to the weld. This study shows that a fixed defocused laser beam can successfully preheat alumina substrates to the high temperatures required for welding; however

  9. Implementation of generalized quantum measurements for unambiguous discrimination of multiple non-orthogonal coherent states.

    PubMed

    Becerra, F E; Fan, J; Migdall, A

    2013-01-01

    Generalized quantum measurements implemented to allow for measurement outcomes termed inconclusive can perform perfect discrimination of non-orthogonal states, a task which is impossible using only measurements with definitive outcomes. Here we demonstrate such generalized quantum measurements for unambiguous discrimination of four non-orthogonal coherent states and obtain their quantum mechanical description, the positive-operator valued measure. For practical realizations of this positive-operator valued measure, where noise and realistic imperfections prevent perfect unambiguous discrimination, we show that our experimental implementation outperforms any ideal standard-quantum-limited measurement performing the same non-ideal unambiguous state discrimination task for coherent states with low mean photon numbers. PMID:23774177

  10. Efficient local fixing of photorefractive polymer hologram using a laser beam.

    PubMed

    Li, Guoqiang; Wang, Peng

    2010-03-15

    We propose and demonstrate a novel technique for efficient local fixing of photorefractive polymer hologram using a laser beam. In the technique, a CO(2) laser beam is used to heat the sample and a local hologram can be fixed easier than previous methods. By using thinner glass substrates for the photorefractive device, the hologram can be fixed efficiently and at much faster speed. The fixation efficiency can be greater than 80% and the hologram can be fixed in the order of a second. This technique is critical for dynamic holographic three-dimensional display and holographic data storage. PMID:20383297

  11. Non-Orthogonality of Seafloor Spreading: A New Look at Fast Spreading Centers

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Gordon, R. G.

    2015-12-01

    Most of Earth's surface is created by seafloor spreading. While most seafloor spreading is orthogonal, that is, the strike of mid-ocean ridge segments is perpendicular to nearby transform faults, examples of significant non-orthogonality have been noted since the 1970s, in particular in regions of slow seafloor spreading such as the western Gulf of Aden with non-orthogonality up to 45°. In contrast, here we focus on fast and ultra-fast seafloor spreading along the East Pacific Rise. To estimate non-orthogonality, we compare ridge-segment strikes with the direction of plate motion determined from the angular velocity that best fits all the data along the boundary of a single plate pair [DeMets et al., 2010]. The advantages of this approach include greater accuracy and the ability to estimate non-orthogonality where there are no nearby transform faults. Estimating the strikes of fast-spreading mid-ocean ridge segments present several challenges as non-transform offsets on various scales affect the estimate of the strike. While spreading is orthogonal or nearly orthogonal along much of the East Pacific Rise, some ridge segments along the Pacific-Nazca boundary near 30°S and near 16°S-22°S deviate from orthogonality by as much as 6°-12° even when we exclude the portions of mid-ocean ridge segments involved in overlapping spreading centers. Thus modest but significant non-orthogonality occurs where seafloor spreading is the fastest on the planet. If a plume lies near the ridge segment, we assume it contributes to magma overpressure along the ridge segment [Abelson & Agnon, 1997]. We further assume that the contribution to magma overpressure is proportional to the buoyancy flux of the plume [Sleep, 1990] and inversely proportional to the distance between the mid-ocean ridge segment and a given plume. We find that the non-orthogonal angle tends to decrease with increasing spreading rate and with increasing distance between ridge segment and plume.

  12. Accurate Calculation of Oscillator Strengths for CI II Lines Using Non-orthogonal Wavefunctions

    NASA Technical Reports Server (NTRS)

    Tayal, S. S.

    2004-01-01

    Non-orthogonal orbitals technique in the multiconfiguration Hartree-Fock approach is used to calculate oscillator strengths and transition probabilities for allowed and intercombination lines in Cl II. The relativistic corrections are included through the Breit-Pauli Hamiltonian. The Cl II wave functions show strong term dependence. The non-orthogonal orbitals are used to describe the term dependence of radial functions. Large sets of spectroscopic and correlation functions are chosen to describe adequately strong interactions in the 3s(sup 2)3p(sup 3)nl (sup 3)Po, (sup 1)Po and (sup 3)Do Rydberg series and to properly account for the important correlation and relaxation effects. The length and velocity forms of oscillator strength show good agreement for most transitions. The calculated radiative lifetime for the 3s3p(sup 5) (sup 3)Po state is in good agreement with experiment.

  13. The gravitational Hamiltonian in the presence of non-orthogonal boundaries

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.; Hunter, C. J.

    1996-10-01

    This paper generalizes earlier work on Hamiltonian boundary terms by omitting the requirement that the spacelike hypersurfaces 0264-9381/13/10/012/img1 intersect the timelike boundary 0264-9381/13/10/012/img2 orthogonally. The expressions for the action and Hamiltonian are calculated and the required subtraction of a background contribution is discussed. The new features of a Hamiltonian formulation with non-orthogonal boundaries are then illustrated in two examples.

  14. Preparation of a primary argon beam for the CERN fixed target physics

    SciTech Connect

    Küchler, D. O’Neil, M.; Scrivens, R.; Thomae, R.

    2014-02-15

    The fixed target experiment NA61 in the North Area of the Super Proton Synchrotron is studying phase transitions in strongly interacting matter. Up to now they used the primary beams available from the CERN accelerator complex (protons and lead ions) or fragmented beams created from the primary lead ion beam. To explore a wider range of energies and densities a request was made to provide primary argon and xenon beams. This paper describes the results of the setting up and 10 week test run of the Ar{sup 11+} beam from the 14.5 GHz ECR ion source and the linear accelerator (Linac3) at CERN.

  15. Non-Orthogonality of Seafloor Spreading: A New Look at Fast Spreading Centers

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Gordon, R. G.

    2014-12-01

    Most of Earth's surface is created by seafloor spreading, which is one of a handful of fundamental global tectonic processes. While most seafloor spreading is orthogonal, that is, the strike of mid-ocean ridge segments are perpendicular to transform faults, examples of significant non-orthogonality have been noted since the 1970s, in particular in regions of slow seafloor spreading such as the western Gulf of Aden with the non-orthogonality up to 45°. In contrast, here we focus on fast and ultra-fast seafloor spreading along the East Pacific Rise. For our analysis, instead of comparing the strike of mid-ocean ridges with the strike of nearby transform faults, the azimuth of which can be uncertain, we compare with the direction of plate motion determined from the angular velocity that best fits all the data along the boundary of a single plate pair [DeMet, Gordon, and Argus 2010]. The advantages of our approach include greater accuracy and the ability to estimate non-orthogonality where there are no nearby transform faults. Estimating the strikes of fast-spreading mid-ocean ridge segments present several challenges as non-transform offsets on various scales affect the estimate of the strike. Moreover, the strike may vary considerably within a single ridge segment bounded by transform faults. This is especially evident near overlapping spreading centers along with the strike varies rapidly with distance along a ridge segment. We use various bathymetric data sets to make our estimates including ETOPO1 [Amante and Eakins, 2009] and GeoMapApp [Ryan et al., 2009]. While spreading is orthogonal or nearly orthogonal along much of the East Pacific Rise, it appears that some ridge segments along the Pacific-Nazca boundary near 30°S and near 16°S-22°S deviate significantly from orthogonality by as much as 6°-12° even when we exclude the portions of mid-ocean ridge segments involved in overlapping spreading centers. Thus modest but significant non-orthogonality occurs

  16. Fairness for Non-Orthogonal Multiple Access in 5G Systems

    NASA Astrophysics Data System (ADS)

    Timotheou, Stelios; Krikidis, Ioannis

    2015-10-01

    In non-orthogonal multiple access (NOMA) downlink, multiple data flows are superimposed in the power domain and user decoding is based on successive interference cancellation. NOMA's performance highly depends on the power split among the data flows and the associated power allocation (PA) problem. In this letter, we study NOMA from a fairness standpoint and we investigate PA techniques that ensure fairness for the downlink users under i) instantaneous channel state information (CSI) at the transmitter, and ii) average CSI. Although the formulated problems are non-convex, we have developed low-complexity polynomial algorithms that yield the optimal solution in both cases considered.

  17. Non-orthogonal optical multicarrier access based on filter bank and SCMA.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun

    2015-10-19

    This paper proposes a novel non-orthogonal optical multicarrier access system based on filter bank and sparse code multiple access (SCMA). It offers released frequency offset and better spectral efficiency for multicarrier access. An experiment of 73.68 Gb/s filter bank-based multicarrier (FBMC) SCMA system with 60 km single mode fiber link is performed to demonstrate the feasibility. The comparison between fast Fourier transform (FFT) based multicarrier and the proposed scheme is also investigated in the experiment. PMID:26480395

  18. Transducer Shadowing Explains Observed Underestimates in Vertical Wind Velocity from Non-orthogonal Sonic Anemometers

    NASA Astrophysics Data System (ADS)

    Frank, J. M.; Massman, W. J.; Swiatek, E.; Zimmerman, H.; Ewers, B. E.

    2014-12-01

    Sonic anemometry is fundamental to all eddy-covariance studies of surface energy and ecosystem carbon and water balance. While recent studies have shown that some anemometers underestimate vertical wind, we hypothesize that this is caused by the lack of transducer shadowing correction in non-orthogonal models. We tested this in an experiment comparing three sonic anemometer designs: orthogonal (O), non-orthogonal (NO), and quasi-orthogonal (QO); using four models: K-probe (O) and A-probe (NO) (Applied Technologies, Inc.) and CSAT3 (NO) and CSAT3V (QO) (Campbell Scientific, Inc.). For each of a 12-week experiment at the GLEES AmeriFlux site, five instruments from a pool of twelve (three of each model) were randomly selected and located around a control (CSAT3); mid-week all but the control were re-mounted horizontally. We used Bayesian analysis to test differences between models in half-hour standard deviations (σu, σv, σw, and σT), turbulent kinetic energy (TKE), and the ratio between vertical/horizontal TKE (VHTKE). The K-probe experiences horizontal transducer shadowing which is effectively corrected using an established wind-tunnel derived algorithm. We constructed shadow correction algorithms for the NO/QO anemometers by applying the K-probe function to each non-orthogonal transducer pair (SC1) as well as a stronger correction of twice the magnitude (SC2). While the partitioning of VHTKE was higher in O than NO/QO anemometers, the application of SC1 explained 45-60% of this discrepancy while SC2 overcorrected it. During the horizontal manipulation changes in the NO/QO were moderate in σu (4-8% decrease), very strong in σv (9-11% decrease), and minimal in σw (-3 to 4% change) while only σu measurements changed (3% decrease) with the K-probe. These changes were predicted by both shadow correction algorithms, with SC2 better explaining the data. This confirms our hypothesis while eliminating others that attribute the underestimate to a systematic bias in

  19. Extending the Nonlinear-Beam-Dynamics Concept of 1D Fixed Points to 2D Fixed Lines

    NASA Astrophysics Data System (ADS)

    Franchetti, G.; Schmidt, F.

    2015-06-01

    The origin of nonlinear dynamics traces back to the study of the dynamics of planets with the seminal work of Poincaré at the end of the nineteenth century: Les Méthodes Nouvelles de la Mécanique Céleste, Vols. 1-3 (Gauthier Villars, Paris, 1899). In his work he introduced a methodology fruitful for investigating the dynamical properties of complex systems, which led to the so-called "Poincaré surface of section," which allows one to capture the global dynamical properties of a system, characterized by fixed points and separatrices with respect to regular and chaotic motion. For two-dimensional phase space (one degree of freedom) this approach has been extremely useful and applied to particle accelerators for controlling their beam dynamics as of the second half of the twentieth century. We describe here an extension of the concept of 1D fixed points to fixed lines in two dimensions. These structures become the fundamental entities for characterizing the nonlinear motion in the four-dimensional phase space (two degrees of freedom).

  20. Extending the Nonlinear-Beam-Dynamics Concept of 1D Fixed Points to 2D Fixed Lines.

    PubMed

    Franchetti, G; Schmidt, F

    2015-06-12

    The origin of nonlinear dynamics traces back to the study of the dynamics of planets with the seminal work of Poincaré at the end of the nineteenth century: Les Méthodes Nouvelles de la Mécanique Céleste, Vols. 1-3 (Gauthier Villars, Paris, 1899). In his work he introduced a methodology fruitful for investigating the dynamical properties of complex systems, which led to the so-called "Poincaré surface of section," which allows one to capture the global dynamical properties of a system, characterized by fixed points and separatrices with respect to regular and chaotic motion. For two-dimensional phase space (one degree of freedom) this approach has been extremely useful and applied to particle accelerators for controlling their beam dynamics as of the second half of the twentieth century. We describe here an extension of the concept of 1D fixed points to fixed lines in two dimensions. These structures become the fundamental entities for characterizing the nonlinear motion in the four-dimensional phase space (two degrees of freedom). PMID:26196806

  1. Non-Orthogonality of Seafloor Spreading: A New Global Survey Building on the MORVEL Plate Motion Project

    NASA Astrophysics Data System (ADS)

    Throckmorton, C. R.; Zhang, T.; Gordon, R. G.

    2013-12-01

    Most of Earth's surface is created by seafloor spreading, which is one of a handful of fundamental global tectonic processes. While most seafloor spreading is orthogonal, that is, the strike of mid-ocean ridge segments are perpendicular to transform faults, examples of significant non-orthogonality have been noted since the 1970s, in particular in regions of slow seafloor spreading such as the western Gulf of Aden. Here we present a new global analysis of non-orthogonality of seafloor spreading by building on the results of the MORVEL global plate motion project including both new estimates of plate angular velocities and global estimates of the strikes of mid-ocean ridge segments [DeMets, Gordon, & Argus, 2010]. For our analysis, instead of comparing the strike of mid-ocean ridges with the strike of nearby transform faults, the azimuth of which can be uncertain, we compare with the direction of plate motion determined from the angular velocity that best fits all the data along the boundary of a single plate pair. The advantages of our approach include greater accuracy and the ability to estimate non-orthogonality where there are no nearby transform faults. Unsurprisingly we confirm that most seafloor spreading is within a few degrees of orthogonality. Moreover we confirm non-orthogonality in many previously recognized regions of slow seafloor spreading. Surprisingly, however, we find non-orthogonality in several regions of fast seafloor spreading. Implications for mid-ocean ridge processes and hypothesized lithosphere deformation will be discussed.

  2. Efficient computation of Hamiltonian matrix elements between non-orthogonal Slater determinants

    NASA Astrophysics Data System (ADS)

    Utsuno, Yutaka; Shimizu, Noritaka; Otsuka, Takaharu; Abe, Takashi

    2013-01-01

    We present an efficient numerical method for computing Hamiltonian matrix elements between non-orthogonal Slater determinants, focusing on the most time-consuming component of the calculation that involves a sparse array. In the usual case where many matrix elements should be calculated, this computation can be transformed into a multiplication of dense matrices. It is demonstrated that the present method based on the matrix-matrix multiplication attains ˜80% of the theoretical peak performance measured on systems equipped with modern microprocessors, a factor of 5-10 better than the normal method using indirectly indexed arrays to treat a sparse array. The reason for such different performances is discussed from the viewpoint of memory access.

  3. Simultaneous Source Localization and Polarization Estimation via Non-Orthogonal Joint Diagonalization with Vector-Sensors

    PubMed Central

    Gong, Xiao-Feng; Wang, Ke; Lin, Qiu-Hua; Liu, Zhi-Wen; Xu, You-Gen

    2012-01-01

    Joint estimation of direction-of-arrival (DOA) and polarization with electromagnetic vector-sensors (EMVS) is considered in the framework of complex-valued non-orthogonal joint diagonalization (CNJD). Two new CNJD algorithms are presented, which propose to tackle the high dimensional optimization problem in CNJD via a sequence of simple sub-optimization problems, by using LU or LQ decompositions of the target matrices as well as the Jacobi-type scheme. Furthermore, based on the above CNJD algorithms we present a novel strategy to exploit the multi-dimensional structure present in the second-order statistics of EMVS outputs for simultaneous DOA and polarization estimation. Simulations are provided to compare the proposed strategy with existing tensorial or joint diagonalization based methods. PMID:22737015

  4. A New Algorithm for Complex Non-Orthogonal Joint Diagonalization Based on Shear and Givens Rotations

    NASA Astrophysics Data System (ADS)

    Mesloub, Ammar; Abed-Meraim, Karim; Belouchrani, Adel

    2014-04-01

    This paper introduces a new algorithm to approximate non orthogonal joint diagonalization (NOJD) of a set of complex matrices. This algorithm is based on the Frobenius norm formulation of the JD problem and takes advantage from combining Givens and Shear rotations to attempt the approximate joint diagonalization (JD). It represents a non trivial generalization of the JDi (Joint Diagonalization) algorithm (Souloumiac 2009) to the complex case. The JDi is first slightly modified then generalized to the CJDi (i.e. Complex JDi) using complex to real matrix transformation. Also, since several methods exist already in the literature, we propose herein a brief overview of existing NOJD algorithms then we provide an extensive comparative study to illustrate the effectiveness and stability of the CJDi w.r.t. various system parameters and application contexts.

  5. Spatio-Temporal Evolutions of Non-Orthogonal Equatorial Wave Modes Derived from Observations

    NASA Astrophysics Data System (ADS)

    Barton, C.; Cai, M.

    2015-12-01

    Equatorial waves have been studied extensively due to their importance to the tropical climate and weather systems. Historically, their activity is diagnosed mainly in the wavenumber-frequency domain. Recently, many studies have projected observational data onto parabolic cylinder functions (PCF), which represent the meridional structure of individual wave modes, to attain time-dependent spatial wave structures. In this study, we propose a methodology that seeks to identify individual wave modes in instantaneous fields of observations by determining their projections on PCF modes according to the equatorial wave theory. The new method has the benefit of yielding a closed system with a unique solution for all waves' spatial structures, including IG waves, for a given instantaneous observed field. We have applied our method to the ERA-Interim reanalysis dataset in the tropical stratosphere where the wave-mean flow interaction mechanism for the quasi-biennial oscillation (QBO) is well-understood. We have confirmed the continuous evolution of the selection mechanism for equatorial waves in the stratosphere from observations as predicted by the theory for the QBO. This also validates the proposed method for decomposition of observed tropical wave fields into non-orthogonal equatorial wave modes.

  6. A Novel Attitude Estimation Algorithm Based on the Non-Orthogonal Magnetic Sensors

    PubMed Central

    Zhu, Jianliang; Wu, Panlong; Bo, Yuming

    2016-01-01

    Because the existing extremum ratio method for projectile attitude measurement is vulnerable to random disturbance, a novel integral ratio method is proposed to calculate the projectile attitude. First, the non-orthogonal measurement theory of the magnetic sensors is analyzed. It is found that the projectile rotating velocity is constant in one spinning circle and the attitude error is actually the pitch error. Next, by investigating the model of the extremum ratio method, an integral ratio mathematical model is established to improve the anti-disturbance performance. Finally, by combining the preprocessed magnetic sensor data based on the least-square method and the rotating extremum features in one cycle, the analytical expression of the proposed integral ratio algorithm is derived with respect to the pitch angle. The simulation results show that the proposed integral ratio method gives more accurate attitude calculations than does the extremum ratio method, and that the attitude error variance can decrease by more than 90%. Compared to the extremum ratio method (which collects only a single data point in one rotation cycle), the proposed integral ratio method can utilize all of the data collected in the high spin environment, which is a clearly superior calculation approach, and can be applied to the actual projectile environment disturbance. PMID:27213389

  7. Optimized Non-Orthogonal Localized Orbitals for Linear Scaling Quantum Monte Carlo calculations

    NASA Astrophysics Data System (ADS)

    Williamson, Andrew; Reboredo, Fernando; Galli, Giulia

    2004-03-01

    It has been shown [1] that Quantum Monte Carlo calculations of total energies of interacting systems can be made to scale nearly linearly with the number of electrons (N), by using localized single particle orbitals to construct Slater determinants. Here we propose a new way of defining the localized orbitals required for O(N)-QMC calculation, by minimizing an appropriate cost function yielding a set of N non-orthogonal (NO) localized orbitals considerably smoother in real space than Maximally localized Wannier functions (MLWF). These NO orbitals have better localization properties than MLWFs. We show that for semiconducting systems NO orbitals can be localized in a much smaller region of space than orthogonal orbitals (typically, one eighth of the volume) and give total energies with the same accuracy, thus yielding a linear scaling QMC algorithm which is 5 times faster than the one originally proposed [1]. We also discuss the extension of O(N)-QMC with NO orbitals to the calculations of total energies of metallic systems. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. [1] A. J. Williamson, R.Q. Hood and J.C. Grossman, Phys. Rev. Lett. 87, 246406 (2001)

  8. A Novel Attitude Estimation Algorithm Based on the Non-Orthogonal Magnetic Sensors.

    PubMed

    Zhu, Jianliang; Wu, Panlong; Bo, Yuming

    2016-01-01

    Because the existing extremum ratio method for projectile attitude measurement is vulnerable to random disturbance, a novel integral ratio method is proposed to calculate the projectile attitude. First, the non-orthogonal measurement theory of the magnetic sensors is analyzed. It is found that the projectile rotating velocity is constant in one spinning circle and the attitude error is actually the pitch error. Next, by investigating the model of the extremum ratio method, an integral ratio mathematical model is established to improve the anti-disturbance performance. Finally, by combining the preprocessed magnetic sensor data based on the least-square method and the rotating extremum features in one cycle, the analytical expression of the proposed integral ratio algorithm is derived with respect to the pitch angle. The simulation results show that the proposed integral ratio method gives more accurate attitude calculations than does the extremum ratio method, and that the attitude error variance can decrease by more than 90%. Compared to the extremum ratio method (which collects only a single data point in one rotation cycle), the proposed integral ratio method can utilize all of the data collected in the high spin environment, which is a clearly superior calculation approach, and can be applied to the actual projectile environment disturbance. PMID:27213389

  9. Low crosstalk optical hierarchical authentication with a fixed random phase lock based on two beams interference

    NASA Astrophysics Data System (ADS)

    Lu, Dajiang; He, Wenqi; Peng, Xiang

    2015-09-01

    We propose a novel method to achieve the purpose of hierarchical authentication based on two beams interference. In this method, different target images indicating different authentication levels are analytically encoded into corresponding phase-only masks (phase keys) and amplitude-only masks (amplitude keys) with the help of a random phase mask, which is created in advance and acts as the fixed lock of this authentication system. For the authentication process, a legal user can obtain a specified target image at the output plane if his/her phase key, and amplitude key, which should be settled close against the fixed internal phase lock, are respectively illuminated by two coherent beams. By comparing the target image with all the standard certification images in the database, the system can thus verify the user's identity. In simple terms, this system can not only confirm the legality of a user but also distinguish his/her identity level. Moreover, in despite of the internal phase lock of this system being fixed, the crosstalk between different pairs of keys hold by different users is low. Theoretical analysis and numerical simulation are both provided to demonstrate the validity of this method.

  10. A Non-Orthogonal Block-Localized Effective Hamiltonian Approach for Chemical and Enzymatic Reactions

    PubMed Central

    Cembran, Alessandro; Payaka, Apirak; Lin, Yen-lin; Xie, Wangshen; Mo, Yirong; Song, Lingchun; Gao, Jiali

    2010-01-01

    The effective Hamiltonian-molecular orbital and valence bond (EH-MOVB) method based on non-orthogonal block-localized fragment orbitals has been implemented into the program CHARMM for molecular dynamics simulations of chemical and enzymatic reactions, making use of semiempirical quantum mechanical models. Building upon ab initio MOVB theory, we make use of two parameters in the EH-MOVB method to fit the barrier height and the relative energy between the reactant and product state for a given chemical reaction to be in agreement with experiment or high-level ab initio or density functional results. Consequently, the EH-MOVB method provides a highly accurate and computationally efficient QM/MM model for dynamics simulation of chemical reactions in solution. The EH-MOVB method is illustrated by examination of the potential energy surface of the hydride transfer reaction from trimethylamine to a flavin cofactor model in the gas phase. In the present study, we employed the semiempirical AM1 model, which yields a reaction barrier that is more than 5 kcal/mol too high. We use a parameter calibration procedure for the EH-MOVB method similar to that employed to adjust the results of semiempirical and empirical models. Thus, the relative energy of these two diabatic states can be shifted to reproduce the experimental energy of reaction, and the barrier height is optimized to reproduce the desired (accurate) value by adding a constant to the off-diagonal matrix element. The present EH-MOVB method offers a viable approach to characterizing solvent and protein-reorganization effects in the realm of combined QM/MM simulations. PMID:20694172

  11. Non-orthogonal spin-adaptation of coupled cluster methods: A new implementation of methods including quadruple excitations

    SciTech Connect

    Matthews, Devin A.; Stanton, John F.

    2015-02-14

    The theory of non-orthogonal spin-adaptation for closed-shell molecular systems is applied to coupled cluster methods with quadruple excitations (CCSDTQ). Calculations at this level of detail are of critical importance in describing the properties of molecular systems to an accuracy which can meet or exceed modern experimental techniques. Such calculations are of significant (and growing) importance in such fields as thermodynamics, kinetics, and atomic and molecular spectroscopies. With respect to the implementation of CCSDTQ and related methods, we show that there are significant advantages to non-orthogonal spin-adaption with respect to simplification and factorization of the working equations and to creating an efficient implementation. The resulting algorithm is implemented in the CFOUR program suite for CCSDT, CCSDTQ, and various approximate methods (CCSD(T), CC3, CCSDT-n, and CCSDT(Q))

  12. The VOLMAX Transient Electromagnetic Modeling System, Including Sub-Cell Slots and Wires on Random Non-Orthogonal Cells

    SciTech Connect

    Riley, D.J.; Turner, C.D.

    1997-12-31

    VOLMAX is a three-dimensional transient volumetric Maxwell equation solver that operates on standard rectilinear finite-difference time-domain (FDTD) grids, non-orthogonal unstructured grids, or a combination of both types (hybrid grids). The algorithm is fully explicit. Open geometries are typically solved by embedding multiple unstructured regions into a simple rectilinear FDTD mesh. The grid types are fully connected at the mesh interfaces without the need for complex spatial interpolation. The approach permits detailed modeling of complex geometry while mitigating the large cell count typical of non-orthogonal cells such as tetrahedral elements. To further improve efficiency, the unstructured region carries a separate time step that sub-cycles relative to the time-step used in the FDTD mesh.

  13. Axisymmetric scattering of an acoustical Bessel beam by a rigid fixed spheroid.

    PubMed

    Mitri, Farid G

    2015-10-01

    Based on the partial-wave series expansion (PWSE) method in spherical coordinates, a formal analytical solution for the acoustic scattering of a zeroth-order Bessel acoustic beam centered on a rigid fixed (oblate or prolate) spheroid is provided. The unknown scattering coefficients of the spheroid are determined by solving a system of linear equations derived for the Neumann boundary condition. Numerical results for the modulus of the backscattered pressure (θ = π) in the near field and the backscattering form function in the far field for both prolate and oblate spheroids are presented and discussed, with particular emphasis on the aspect ratio (i.e., the ratio of the major axis over the minor axis of the spheroid), the half-cone angle of the Bessel beam, and the dimensionless frequency. The plots display periodic oscillations (versus the dimensionless frequency) because of the interference of specularly reflected waves in the backscattering direction with circumferential Franz' waves circumnavigating the surface of the spheroid in the surrounding fluid. Moreover, the 3-D directivity patterns illustrate the near- and far-field axisymmetric scattering. Investigations in underwater acoustics, particle levitation, scattering, and the detection of submerged elongated objects and other related applications utilizing Bessel waves would benefit from the results of the present study. PMID:26470043

  14. Physics Opportunities of a Fixed-Target Experiment using the LHC Beams

    SciTech Connect

    Brodsky, S.J.; Fleuret, F.; Hadjidakis, C.; Lansberg, J.P.; /Orsay, IPN

    2012-03-16

    We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC extracted by a bent crystal. In a proton run with the LHC 7-TeV beam, one can analyze pp, pd and pA collisions at center-of-mass energy {radical}s{sub NN} {approx_equal} 115 GeV and even higher using the Fermi motion of the nucleons in a nuclear target. In a lead run with a 2.76 TeV-per-nucleon beam, {radical}s{sub NN} is as high as 72 GeV. Bent crystals can be used to extract about 5 x 10{sup 8} protons/sec; the integrated luminosity over a year reaches 0.5 fb{sup -1} on a typical 1 cm-long target without nuclear species limitation. We emphasize that such an extraction mode does not alter the performance of the collider experiments at the LHC. By instrumenting the target-rapidity region, gluon and heavy-quark distributions of the proton and the neutron can be accessed at large x and even at x larger than unity in the nuclear case. Single diffractive physics and, for the first time, the large negative-xF domain can be accessed. The nuclear target-species versatility provides a unique opportunity to study nuclear matter versus the features of the hot and dense matter formed in heavy-ion collisions, including the formation of the quark-gluon plasma, which can be studied in PbA collisions over the full range of target-rapidity domain with a large variety of nuclei. The polarization of hydrogen and nuclear targets allows an ambitious spin program, including measurements of the QCD lensing effects which underlie the Sivers single-spin asymmetry, the study of transversity distributions and possibly of polarized parton distributions. We also emphasize the potential offered by pA ultra-peripheral collisions where the nucleus target A is used as a coherent photon source, mimicking photoproduction processes in ep collisions. Finally, we note that W and Z bosons can be produced and detected in a fixed-target experiment and in their

  15. Physics opportunities of a fixed-target experiment using LHC beams

    NASA Astrophysics Data System (ADS)

    Brodsky, S. J.; Fleuret, F.; Hadjidakis, C.; Lansberg, J. P.

    2013-01-01

    We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC extracted by a bent crystal. In a proton run with the LHC 7 TeV beam, one can analyze pp, pd and pA collisions at center-of-mass energy √{s}≃115 GeV and even higher using the Fermi motion of the nucleons in a nuclear target. In a lead run with a 2.76 TeV-per-nucleon beam, √{s} is as high as 72 GeV. Bent crystals can be used to extract about 5×108 protons/s; the integrated luminosity over a year reaches 0.5 fb-1 on a typical 1 cm long target without nuclear species limitation. We emphasize that such an extraction mode does not alter the performance of the collider experiments at the LHC. By instrumenting the target-rapidity region, gluon and heavy-quark distributions of the proton and the neutron can be accessed at large x and even at x larger than unity in the nuclear case. Single diffractive physics and, for the first time, the large negative-xF domain can be accessed. The nuclear target-species versatility provides a unique opportunity to study nuclear matter versus the features of the hot and dense matter formed in heavy-ion collisions, including the formation of the quark-gluon plasma, which can be studied in PbA collisions over the full range of target-rapidity domain with a large variety of nuclei. The polarization of hydrogen and nuclear targets allows an ambitious spin program, including measurements of the QCD lensing effects which underlie the Sivers single-spin asymmetry, the study of transversity distributions and possibly of polarized parton distributions. We also emphasize the potential offered by pA ultra-peripheral collisions where the nucleus target A is used as a coherent photon source, mimicking photoproduction processes in ep collisions. Finally, we note that W and Z bosons can be produced and detected in a fixed-target experiment and in their threshold domain for the first time, providing new ways to

  16. On the Performance of Non-Orthogonal Multiple Access in 5G Systems with Randomly Deployed Users

    NASA Astrophysics Data System (ADS)

    Ding, Zhiguo; Yang, Zheng; Fan, Pingzhi; Poor, H. Vincent

    2014-12-01

    In this letter, the performance of non-orthogonal multiple access (NOMA) is investigated in a cellular downlink scenario with randomly deployed users. The developed analytical results show that NOMA can achieve superior performance in terms of ergodic sum rates; however, the outage performance of NOMA depends critically on the choices of the users' targeted data rates and allocated power. In particular, a wrong choice of the targeted data rates and allocated power can lead to a situation in which the user's outage probability is always one, i.e. the user's targeted quality of service will never be met.

  17. Quarkonium Physics at a Fixed-Target Experiment Using the LHC Beams

    SciTech Connect

    Lansberg, J.P.; Brodsky, S.J.; Fleuret, F.; Hadjidakis, C.; /Orsay, IPN

    2012-04-09

    We outline the many quarkonium-physics opportunities offered by a multi-purpose fixed-target experiment using the p and Pb LHC beams extracted by a bent crystal. This provides an integrated luminosity of 0.5 fb{sup -1} per year on a typical 1cm-long target. Such an extraction mode does not alter the performance of the collider experiments at the LHC. With such a high luminosity, one can analyse quarkonium production in great details in pp, pd and pA collisions at {radical}s{sub NN} {approx_equal} 115 GeV and at {radical}s{sub NN} {approx_equal} 72 GeV in PbA collisions. In a typical pp (pA) run, the obtained quarkonium yields per unit of rapidity are 2-3 orders of magnitude larger than those expected at RHIC and about respectively 10 (70) times larger than for ALICE. In PbA, they are comparable. By instrumenting the target-rapidity region, the large negative-x{sub F} domain can be accessed for the first time, greatly extending previous measurements by Hera-B and E866. Such analyses should help resolving the quarkonium-production controversies and clear the way for gluon PDF extraction via quarkonium studies. The nuclear target-species versatility provides a unique opportunity to study nuclear matter and the features of the hot and dense matter formed in PbA collisions. A polarised proton target allows the study of transverse-spin asymmetries in J/{Psi} and {Upsilon} production, providing access to the gluon and charm Sivers functions.

  18. Design verification for sub-70-nm DRAM nodes via metal fix using E-beam direct write

    NASA Astrophysics Data System (ADS)

    Keil, K.; Jaschinsky, P.; Hohle, C.; Choi, K.-H.; Schneider, R.; Tesauro, M.; Thrum, F.; Zimmermann, R.; Kretz, J.

    2009-01-01

    Because of mask cost reduction, electron beam direct write (EBDW) is implemented for special applications such as rapid prototyping or small volume production in semiconductor industry. One of the most promising applications for EBDW is design verification by means of metal fix. Due to write time constrains, Mix & Match solutions have to be developed at smaller nodes. This study reports on several Mix and Match processes for the integration of E-Beam lithography into the optical litho process flow of Qimonda's 70 nm and 58 nm DRAM nodes. Different metal layers have been patterned in part with DUV litho followed by E-Beam litho using a 50 kV Vistec SB3050 shaped electron beam direct writer. All hardmask patterns were then simultaneously transferred into the DRAM stack. After full chip processing a yield study comprising electrical device characterization and defect investigation was performed. We show detailed results including CD and OVL as well as improvements of the alignment mark recognition. The yield of the E-Beam processed chips was found to be within the range of wafer-to-wafer fluctuation of the POR hardware. We also report on metal fix by electrical cutting of selected diodes in large chip scales which usually cannot be accessed with FIB methods. In summary, we show the capability of EBDW for quick and flexible design verification.

  19. Renovation of the fixing and loading factors of the beam by the spectral data of free flexural vibrations

    NASA Astrophysics Data System (ADS)

    Akhymbek, Meiram Erkanatuly; Yessirkegenov, Nurgissa Amankeldiuly; Sadybekov, Makhmud Abdysametovich

    2015-09-01

    In the current paper, the problem of bending vibrations of a beam in which the binding on the right end is unknown and not available for visual inspection is studied. The main objective is to study an inverse problem: find additional unknown boundary conditions by additional spectral data, i.e., the conditions of fixing the right end of the rod. In this work, unlike many other works, as such additional conditions we choose the first natural frequencies (eigenvalues) of two new problems corresponding to the problem of bending vibrations of a beam with loads of different weights at the central point.

  20. Renovation of the fixing and loading factors of the beam by the spectral data of free flexural vibrations

    SciTech Connect

    Akhymbek, Meiram Erkanatuly; Yessirkegenov, Nurgissa Amankeldiuly; Sadybekov, Makhmud Abdysametovich

    2015-09-18

    In the current paper, the problem of bending vibrations of a beam in which the binding on the right end is unknown and not available for visual inspection is studied. The main objective is to study an inverse problem: find additional unknown boundary conditions by additional spectral data, i.e., the conditions of fixing the right end of the rod. In this work, unlike many other works, as such additional conditions we choose the first natural frequencies (eigenvalues) of two new problems corresponding to the problem of bending vibrations of a beam with loads of different weights at the central point.

  1. Three Dimensional Wind Speed and Flux Measurement over a Rain-fed Soybean Field Using Orthogonal and Non-orthogonal Sonic Anemometer Designs

    NASA Astrophysics Data System (ADS)

    Thomas, T.; Suyker, A.; Burba, G. G.; Billesbach, D.

    2014-12-01

    The eddy covariance method for estimating fluxes of trace gases, energy and momentum in the constant flux layer above a plant canopy fundamentally relies on accurate measurements of the vertical wind speed. This wind speed is typically measured using a three dimensional ultrasonic anemometer. These anemometers incorporate designs with transducer sets that are aligned either orthogonally or non-orthogonally. Previous studies comparing the two designs suggest differences in measured 3D wind speed components, in particular vertical wind speed, from the non-orthogonal transducer relative to the orthogonal design. These differences, attributed to additional flow distortion caused by the non-orthogonal transducer arrangement, directly affect fluxes of trace gases, energy and momentum. A field experiment is being conducted over a rain-fed soybean field at the AmeriFlux site (US-Ne3) near Mead, Nebraska. In this study, ultrasonic anemometers featuring orthogonal transducer sets (ATI Vx Probe) and non-orthogonal transducer sets (Gill R3-100) collect high frequency wind vector and sonic temperature data. Sensible heat and momentum fluxes and other key sonic performance data are evaluated based on environmental parameters including wind speed, wind direction, temperature, and angle of attack. Preliminary field experiment results are presented.

  2. Reliable Attention Network Scores and Mutually Inhibited Inter-network Relationships Revealed by Mixed Design and Non-orthogonal Method

    PubMed Central

    Wang, Yi-Feng; Jing, Xiu-Juan; Liu, Feng; Li, Mei-Ling; Long, Zhi-Liang; Yan, Jin H.; Chen, Hua-Fu

    2015-01-01

    The attention system can be divided into alerting, orienting, and executive control networks. The efficiency and independence of attention networks have been widely tested with the attention network test (ANT) and its revised versions. However, many studies have failed to find effects of attention network scores (ANSs) and inter-network relationships (INRs). Moreover, the low reliability of ANSs can not meet the demands of theoretical and empirical investigations. Two methodological factors (the inter-trial influence in the event-related design and the inter-network interference in orthogonal contrast) may be responsible for the unreliability of ANT. In this study, we combined the mixed design and non-orthogonal method to explore ANSs and directional INRs. With a small number of trials, we obtained reliable and independent ANSs (split-half reliability of alerting: 0.684; orienting: 0.588; and executive control: 0.616), suggesting an individual and specific attention system. Furthermore, mutual inhibition was observed when two networks were operated simultaneously, indicating a differentiated but integrated attention system. Overall, the reliable and individual specific ANSs and mutually inhibited INRs provide novel insight into the understanding of the developmental, physiological and pathological mechanisms of attention networks, and can benefit future experimental and clinical investigations of attention using ANT. PMID:25997025

  3. Human performance capabilities in a simulated space station-like environment. 1: Fixed beam luminance and location

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Bartz, A. E.; Zahn, J. R.

    1972-01-01

    The effects of a fixed, intense, one-foot diameter beam of simulated sunlight imaged within the field of view, upon responses to a battery of visual, body balance and stability, eye-hand coordination, and mental tests were studied. Each subject's electrocardiogram and electro-oculograms (vertical and horizontal) were recorded throughout each two-hour testing period within the space-station-like environment. It is possible to say that both subjects adapted to the brightly illuminated white panels in approximately 30 seconds after their first exposure each day and thereafter did not experience ocular fatigue, eye strain, or other kinds of disturbances as a result of these viewing conditions.

  4. Acoustic scattering of a Bessel vortex beam by a rigid fixed spheroid

    NASA Astrophysics Data System (ADS)

    Mitri, F. G.

    2015-12-01

    Partial-wave series representation of the acoustic scattering field of high-order Bessel vortex beams by rigid oblate and prolate spheroids using the modal matching method is developed. The method, which is applicable to slightly elongated objects at low-to-moderate frequencies, requires solving a system of linear equations which depends on the partial-wave index n and the order of the Bessel vortex beam m using truncated partial-wave series expansions (PWSEs), and satisfying the Neumann boundary condition for a rigid immovable surface in the least-squares sense. This original semi-analytical approach developed for Bessel vortex beams is demonstrated for finite oblate and prolate spheroids, where the mathematical functions describing the spheroidal geometry are written in a form involving single angular (polar) integrals that are numerically computed. The transverse (θ = π / 2) and 3D scattering directivity patterns are evaluated in the far-field for both prolate and oblate spheroids, with particular emphasis on the aspect ratio (i.e., the ratio of the major axis over the minor axis of the spheroid) not exceeding 3:1, the half-cone angle β and order m of the Bessel vortex beam, as well as the dimensionless size parameter kr0. Periodic oscillations in the magnitude plots of the far-field scattering form function are observed, which result from the interference of the reflected waves with the circumferential (Franz') waves circumnavigating the surface of the spheroid in the surrounding fluid. Moreover, the 3D directivity patterns illustrate the far-field scattering from the spheroid, that vanishes in the forward (θ = 0) and backward (θ = π) directions. Particular applications in underwater acoustics and scattering, acoustic levitation and the detection of submerged elongated objects using Bessel vortex waves to name a few, would benefit from the results of the present investigation.

  5. Use of transfer maps for modeling beam dynamics in a nonscaling fixed-field alternating-gradient accelerator

    NASA Astrophysics Data System (ADS)

    Giboudot, Y.; Wolski, A.

    2012-04-01

    Transfer maps for magnetic components are fundamental to studies of beam dynamics in accelerators. In the work presented here, transfer maps are computed in Taylor form for a particle moving through any specified magnetostatic field by applying an explicit symplectic integrator in a differential algebra code. The techniques developed are illustrated by their application to study the beam dynamics in the electron model for many applications (EMMA), the first nonscaling fixed-field alternating-gradient accelerator ever built. The EMMA lattice has 4 degrees of freedom (strength and transverse position of each of the two quadrupoles in each periodic cell). Transfer maps may be used to predict efficiently the dynamics in any lattice configuration. The transfer map is represented by a mixed variable generating function, obtained by interpolation between the maps for a set of reference configurations: use of mixed variable generating functions ensures the symplecticity of the map. An optimization routine uses the interpolation technique to look for a lattice defined by four constraints on the time of flight at different beam energies. This provides a way to determine the lattice configuration required to produce the desired dynamical characteristics. These tools are benchmarked against data from the recent EMMA commissioning.

  6. Novel methods for configuration interaction and orbital optimization for wave functions containing non-orthogonal orbitals with applications to the chromium dimer and trimer

    NASA Astrophysics Data System (ADS)

    Olsen, Jeppe

    2015-09-01

    A novel algorithm for performing configuration interaction (CI) calculations using non-orthogonal orbitals is introduced. In the new algorithm, the explicit calculation of the Hamiltonian matrix is replaced by the direct evaluation of the Hamiltonian matrix times a vector, which allows expressing the CI-vector in a bi-orthonormal basis, thereby drastically reducing the computational complexity. A new non-orthogonal orbital optimization method that employs exponential mappings is also described. To allow non-orthogonal transformations of the orbitals, the standard exponential mapping using anti-symmetric operators is supplemented with an exponential mapping based on a symmetric operator in the active orbital space. Expressions are obtained for the orbital gradient and Hessian, which involve the calculation of at most two-body density matrices, thereby avoiding the time-consuming calculation of the three- and four-body density matrices of the previous approaches. An approach that completely avoids the calculation of any four-body terms with limited degradation of convergence is also devised. The novel methods for non-orthogonal configuration interaction and orbital optimization are applied to the chromium dimer and trimer. For internuclear distances that are typical for chromium clusters, it is shown that a reference configuration consisting of optimized singly occupied active orbitals is sufficient to give a potential curve that is in qualitative agreement with complete active space self-consistent field (CASSCF) calculations containing more than 500 × 106 determinants. To obtain a potential curve that deviates from the CASSCF curve by less than 1 mHartree, it is sufficient to add single and double excitations out from the reference configuration.

  7. Novel methods for configuration interaction and orbital optimization for wave functions containing non-orthogonal orbitals with applications to the chromium dimer and trimer.

    PubMed

    Olsen, Jeppe

    2015-09-21

    A novel algorithm for performing configuration interaction (CI) calculations using non-orthogonal orbitals is introduced. In the new algorithm, the explicit calculation of the Hamiltonian matrix is replaced by the direct evaluation of the Hamiltonian matrix times a vector, which allows expressing the CI-vector in a bi-orthonormal basis, thereby drastically reducing the computational complexity. A new non-orthogonal orbital optimization method that employs exponential mappings is also described. To allow non-orthogonal transformations of the orbitals, the standard exponential mapping using anti-symmetric operators is supplemented with an exponential mapping based on a symmetric operator in the active orbital space. Expressions are obtained for the orbital gradient and Hessian, which involve the calculation of at most two-body density matrices, thereby avoiding the time-consuming calculation of the three- and four-body density matrices of the previous approaches. An approach that completely avoids the calculation of any four-body terms with limited degradation of convergence is also devised. The novel methods for non-orthogonal configuration interaction and orbital optimization are applied to the chromium dimer and trimer. For internuclear distances that are typical for chromium clusters, it is shown that a reference configuration consisting of optimized singly occupied active orbitals is sufficient to give a potential curve that is in qualitative agreement with complete active space self-consistent field (CASSCF) calculations containing more than 500 × 10(6) determinants. To obtain a potential curve that deviates from the CASSCF curve by less than 1 mHartree, it is sufficient to add single and double excitations out from the reference configuration. PMID:26395682

  8. Characterization techniques for fixed-field alternating gradient accelerators and beam studies using the KURRI 150 MeV proton FFAG

    NASA Astrophysics Data System (ADS)

    Sheehy, S. L.; Kelliher, D. J.; Machida, S.; Rogers, C.; Prior, C. R.; Volat, L.; Haj Tahar, M.; Ishi, Y.; Kuriyama, Y.; Sakamoto, M.; Uesugi, T.; Mori, Y.

    2016-07-01

    In this paper we describe the methods and tools used to characterize a 150 MeV proton scaling fixed field alternating gradient (FFAG) accelerator at Kyoto University Research Reactor Institute. Many of the techniques used are unique to this class of machine and are thus of relevance to any future FFAG accelerator. For the first time we detail systematic studies undertaken to improve the beam quality of the FFAG. The control of beam quality in this manner is crucial to demonstrating high power operation of FFAG accelerators in future.

  9. SU-E-T-462: Fixed-Jaw Optimization for Critical Structure Sparing in IMRT Treatment Planning: Beam Modeling Cautions for Non-Routine Use

    SciTech Connect

    Price, R; Veltchev, I; Cherian, G; Ma, C

    2014-06-01

    Purpose: Multiple publications exist concerning fixed-jaw utilization to avoid linac carriage shifts and reduce intensity modulated radiotherapy (IMRT) treatment times. The purpose of this work is to demonstrate delivery QA discrepancies and illustrate the need for improved treatment planning system (TPS) commissioning for non-routine use. Methods: A 6cm diameter spherical target was delineated on a virtual phantom containing the Iba Matrixx linear array within the Varian Eclipse TPS. Optimization was performed for target coverage for the following 3 scenarios: a single open, zero degree field where the X and Y jaws completely cover the target; the same field using an asymmetric, fixed-jaw technique where the upper Y jaw does not cover the superior 2cm of the target; and both of the aforementioned directed at the target at 315 and 45 degree gantry angles, respectively. This final orientation was also irradiated on a linac for delivery analysis. A sarcoma patient case was also analyzed where the fixed jaw technique was utilized for kidney sparing. Results: The open beam results were as predicted but the fixed-jaw results demonstrate a pronounced fluence increase along the asymmetric, upper jaw. Analysis of the delivery of the combined beam plan Resultin 83% of pixels evaluated passing gamma criteria of 3%, 3mm DTA. Analysis for the sarcoma patient, in the plane of the shielded kidney, indicated 93% passing although the maximum dose discrepancies in this region were approximately 23%. Conclusion: Optimization within the target is routinely performed using MLC leaf-end characteristics. The fixed-jaw technique forces optimization of target coverage to utilize the penumbra profiles of the associated beamdefining jaw. If the profiles were collected using a common 0.125cc ionization chamber, the resolution may be insufficient resulting in a planvs.-delivery mismatch. It is recommended that high-resolution beam characteristics be considered when non-routine planning

  10. A program for calculating photonic band structures, Green's functions and transmission/reflection coefficients using a non-orthogonal FDTD method

    NASA Astrophysics Data System (ADS)

    Ward, A. J.; Pendry, J. B.

    2000-06-01

    In this paper we present an updated version of our ONYX program for calculating photonic band structures using a non-orthogonal finite difference time domain method. This new version employs the same transparent formalism as the first version with the same capabilities for calculating photonic band structures or causal Green's functions but also includes extra subroutines for the calculation of transmission and reflection coefficients. Both the electric and magnetic fields are placed onto a discrete lattice by approximating the spacial and temporal derivatives with finite differences. This results in discrete versions of Maxwell's equations which can be used to integrate the fields forwards in time. The time required for a calculation using this method scales linearly with the number of real space points used in the discretization so the technique is ideally suited to handling systems with large and complicated unit cells.

  11. Studies of Transverse-Momentum-Dependent Distributions with a Fixed-Target ExpeRiment Using the LHC Beams (AFTER@LHC)

    NASA Astrophysics Data System (ADS)

    Massacrier, L.; Anselmino, M.; Arnaldi, R.; Brodsky, S. J.; Chambert, V.; den Dunnen, W.; Didelez, J. P.; Genolini, B.; Ferreiro, E. G.; Fleuret, F.; Gao, Y.; Hadjidakis, C.; Hřivnáčová, I.; Lansberg, J. P.; Lorcé, C.; Mikkelsen, R.; Pisano, C.; Rakotozafindrabe, A.; Rosier, P.; Schienbein, I.; Schlegel, M.; Scomparin, E.; Trzeciak, B.; Uggerhøj, U. I.; Ulrich, R.; Yang, Z.

    2016-02-01

    We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment -AFTER@LHC- using the p+ or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering ηlab ∈ [1, 5] allows one to measure these asymmetries at large x↑ in the polarised nucleon.

  12. Tilted Gaussian beam propagation in inhomogeneous media.

    PubMed

    Hadad, Yakir; Melamed, Timor

    2010-08-01

    The present work is concerned with applying a ray-centered non-orthogonal coordinate system which is a priori matched to linearly-phased localized aperture field distributions. The resulting beam-waveobjects serve as the building blocks for beam-type spectral expansions of aperture fields in 2D inhomogeneous media that are characterized by a generic wave-velocity profile. By applying a rigorous paraxial-asymptotic analysis, a novel parabolic wave equation is obtained and termed "Non-orthogonal domain parabolic equation"--NoDope. Tilted Gaussian beams, which are exact solutions to this equation, match Gaussian aperture distributions over a plane that is tilted with respect to the beam-axes initial directions. A numerical example, which demonstrates the enhanced accuracy of the tilted Gaussian beams over the conventional ones, is presented as well. PMID:20686589

  13. SU-E-T-273: Radiation Shielding for a Fixed Horizontal-Beam Linac in a Shipping Container and a Conventional Treatment Vault

    SciTech Connect

    Hsieh, M; Balter, P; Beadle, B; Chi, P; Stingo, F; Court, L

    2014-06-01

    Purpose: A fixed horizontal-beam linac, where the patient is treated in a seated position, could lower the overall costs of the treatment unit and room shielding substantially. This design also allows the treatment room and control area to be contained within a reduced space, such as a shipping container. The main application is the introduction of low-cost, high-quality radiation therapy to low- and middle-income regions. Here we consider shielding for upright treatments with a fixed-6MV-beam linac in a shipping container and a conventional treatment vault. Methods: Shielding calculations were done for two treatment room layouts using calculation methods in NCRP Report 151: (1) a shipping container (6m × 2.4m with the remaining space occupied by the console area), and (2) the treatment vault in NCRP 151 (7.8m by 5.4m by 3.4m). The shipping container has a fixed gantry that points in one direction at all times. For the treatment vault, various beam directions were evaluated. Results: The shipping container requires a primary barrier of 168cm concrete (4.5 TVL), surrounded by a secondary barrier of 3.6 TVL. The other walls require between 2.8–3.3 TVL. Multiple shielding calculations were done along the side wall. The results show that patient scatter increases in the forward direction and decreases dramatically in the backward direction. Leakage scatter also varies along the wall, depending largely on the distance between the gantry and the wall. For the treatment room, fixed-beam requires a slightly thicker primary barrier than the conventional linac (0.6 TVL), although this barrier is only needed in the center of one wall. The secondary barrier is different only by 0–0.2 TVL. Conclusion: This work shows that (1) the shipping container option is achievable, using indigenous materials for shielding and (2) upright treatments can be performed in a conventional treatment room with minimal additional shielding. Varian Medical Systems.

  14. Cone beam computed tomography imaging as a primary diagnostic tool for computer-guided surgery and CAD-CAM interim removable and fixed dental prostheses.

    PubMed

    Charette, Jyme R; Goldberg, Jack; Harris, Bryan T; Morton, Dean; Llop, Daniel R; Lin, Wei-Shao

    2016-08-01

    This article describes a digital workflow using cone beam computed tomography imaging as the primary diagnostic tool in the virtual planning of the computer-guided surgery and fabrication of a maxillary interim complete removable dental prosthesis and mandibular interim implant-supported complete fixed dental prosthesis with computer-aided design and computer-aided manufacturing technology. Diagnostic impressions (conventional or digital) and casts are unnecessary in this proposed digital workflow, providing clinicians with an alternative treatment in the indicated clinical scenario. PMID:27086108

  15. Size consistent formulations of the perturb-then-diagonalize Møller-Plesset perturbation theory correction to non-orthogonal configuration interaction.

    PubMed

    Yost, Shane R; Head-Gordon, Martin

    2016-08-01

    In this paper we introduce two size consistent forms of the non-orthogonal configuration interaction with second-order Møller-Plesset perturbation theory method, NOCI-MP2. We show that the original NOCI-MP2 formulation [S. R. Yost, T. Kowalczyk, and T. VanVoorh, J. Chem. Phys. 193, 174104 (2013)], which is a perturb-then-diagonalize multi-reference method, is not size consistent. We also show that this causes significant errors in large systems like the linear acenes. By contrast, the size consistent versions of the method give satisfactory results for singlet and triplet excited states when compared to other multi-reference methods that include dynamic correlation. For NOCI-MP2 however, the number of required determinants to yield similar levels of accuracy is significantly smaller. These results show the promise of the NOCI-MP2 method, though work still needs to be done in creating a more consistent black-box approach to computing the determinants that comprise the many-electron NOCI basis. PMID:27497537

  16. Size consistent formulations of the perturb-then-diagonalize Møller-Plesset perturbation theory correction to non-orthogonal configuration interaction

    NASA Astrophysics Data System (ADS)

    Yost, Shane R.; Head-Gordon, Martin

    2016-08-01

    In this paper we introduce two size consistent forms of the non-orthogonal configuration interaction with second-order Møller-Plesset perturbation theory method, NOCI-MP2. We show that the original NOCI-MP2 formulation [S. R. Yost, T. Kowalczyk, and T. VanVoorh, J. Chem. Phys. 193, 174104 (2013)], which is a perturb-then-diagonalize multi-reference method, is not size consistent. We also show that this causes significant errors in large systems like the linear acenes. By contrast, the size consistent versions of the method give satisfactory results for singlet and triplet excited states when compared to other multi-reference methods that include dynamic correlation. For NOCI-MP2 however, the number of required determinants to yield similar levels of accuracy is significantly smaller. These results show the promise of the NOCI-MP2 method, though work still needs to be done in creating a more consistent black-box approach to computing the determinants that comprise the many-electron NOCI basis.

  17. SU-F-BRD-05: Dosimetric Comparison of Protocol-Based SBRT Lung Treatment Modalities: Statistically Significant VMAT Advantages Over Fixed- Beam IMRT

    SciTech Connect

    Best, R; Harrell, A; Geesey, C; Libby, B; Wijesooriya, K

    2014-06-15

    Purpose: The purpose of this study is to inter-compare and find statistically significant differences between flattened field fixed-beam (FB) IMRT with flattening-filter free (FFF) volumetric modulated arc therapy (VMAT) for stereotactic body radiation therapy SBRT. Methods: SBRT plans using FB IMRT and FFF VMAT were generated for fifteen SBRT lung patients using 6 MV beams. For each patient, both IMRT and VMAT plans were created for comparison. Plans were generated utilizing RTOG 0915 (peripheral, 10 patients) and RTOG 0813 (medial, 5 patients) lung protocols. Target dose, critical structure dose, and treatment time were compared and tested for statistical significance. Parameters of interest included prescription isodose surface coverage, target dose heterogeneity, high dose spillage (location and volume), low dose spillage (location and volume), lung dose spillage, and critical structure maximum- and volumetric-dose limits. Results: For all criteria, we found equivalent or higher conformality with VMAT plans as well as reduced critical structure doses. Several differences passed a Student's t-test of significance: VMAT reduced the high dose spillage, evaluated with conformality index (CI), by an average of 9.4%±15.1% (p=0.030) compared to IMRT. VMAT plans reduced the lung volume receiving 20 Gy by 16.2%±15.0% (p=0.016) compared with IMRT. For the RTOG 0915 peripheral lesions, the volumes of lung receiving 12.4 Gy and 11.6 Gy were reduced by 27.0%±13.8% and 27.5%±12.6% (for both, p<0.001) in VMAT plans. Of the 26 protocol pass/fail criteria, VMAT plans were able to achieve an average of 0.2±0.7 (p=0.026) more constraints than the IMRT plans. Conclusions: FFF VMAT has dosimetric advantages over fixed beam IMRT for lung SBRT. Significant advantages included increased dose conformity, and reduced organs-at-risk doses. The overall improvements in terms of protocol pass/fail criteria were more modest and will require more patient data to establish difference

  18. Whole abdomen radiation therapy in ovarian cancers: a comparison between fixed beam and volumetric arc based intensity modulation

    PubMed Central

    2010-01-01

    Purpose A study was performed to assess dosimetric characteristics of volumetric modulated arcs (RapidArc, RA) and fixed field intensity modulated therapy (IMRT) for Whole Abdomen Radiotherapy (WAR) after ovarian cancer. Methods and Materials Plans for IMRT and RA were optimised for 5 patients prescribing 25 Gy to the whole abdomen (PTV_WAR) and 45 Gy to the pelvis and pelvic nodes (PTV_Pelvis) with Simultaneous Integrated Boost (SIB) technique. Plans were investigated for 6 MV (RA6, IMRT6) and 15 MV (RA15, IMRT15) photons. Objectives were: for both PTVs V90% > 95%, for PTV_Pelvis: Dmax < 105%; for organs at risk, maximal sparing was required. The MU and delivery time measured treatment efficiency. Pre-treatment Quality assurance was scored with Gamma Agreement Index (GAI) with 3% and 3 mm thresholds. Results IMRT and RapidArc resulted comparable for target coverage. For PTV_WAR, V90% was 99.8 ± 0.2% and 93.4 ± 7.3% for IMRT6 and IMRT15, and 98.4 ± 1.7 and 98.6 ± 0.9% for RA6 and RA15. Target coverage resulted improved for PTV_Pelvis. Dose homogeneity resulted slightly improved by RA (Uniformity was defined as U5-95% = D5%-D95%/Dmean). U5-95% for PTV_WAR was 0.34 ± 0.05 and 0.32 ± 0.06 (IMRT6 and IMRT15), 0.30 ± 0.03 and 0.26 ± 0.04 (RA6 and RA15); for PTV_Pelvis, it resulted equal to 0.1 for all techniques. For organs at risk, small differences were observed between the techniques. MU resulted 3130 ± 221 (IMRT6), 2841 ± 318 (IMRT15), 538 ± 29 (RA6), 635 ± 139 (RA15); the average measured treatment time was 18.0 ± 0.8 and 17.4 ± 2.2 minutes (IMRT6 and IMRT15) and 4.8 ± 0.2 (RA6 and RA15). GAIIMRT6 = 97.3 ± 2.6%, GAIIMRT15 = 94.4 ± 2.1%, GAIRA6 = 98.7 ± 1.0% and GAIRA15 = 95.7 ± 3.7%. Conclusion RapidArc showed to be a solution to WAR treatments offering good dosimetric features with significant logistic improvements compared to IMRT. PMID:21078145

  19. Future Fixed Target Facilities

    SciTech Connect

    Melnitchouk, Wolodymyr

    2009-01-01

    We review plans for future fixed target lepton- and hadron-scattering facilities, including the 12 GeV upgraded CEBAF accelerator at Jefferson Lab, neutrino beam facilities at Fermilab, and the antiproton PANDA facility at FAIR. We also briefly review recent theoretical developments which will aid in the interpretation of the data expected from these facilities.

  20. Volumetric-modulated arc radiotherapy for skull-base and non-skull-base head and neck cancer: a treatment planning comparison with fixed Beam IMRT.

    PubMed

    Chen, J; Mok, E; Wang, L; Chen, C; Le, Q-T

    2013-02-01

    The purpose of this study is to compare the dose distribution, monitor units (MUs) and radiation delivery time between volumetric-modulated arc (VMAT) and fix-beam intensity modulated radiotherapy (FB-IMRT) in skull-base and non-skull-base head and neck cancer (HNC). CT datasets of 8 skull-base and 7 non-skull-base HNC were identified. IMRT and VMAT plans were generated. The prescription dose ranged 45-70 Gy (1.8-2.2 Gy/fraction). The VMAT delivery time was measured when these plans were delivered to the patients. The FB-IMRT delivery time was generated on a phantom. Comparison of dose-volume histogram data, MUs, and delivery times was performed using T-test. Our results show that both plans yield similar target volume coverage, homogeneity, and conformity. In skull-base cases, compared to FB-IMRT, VMAT generated significantly smaller hot-spot inside PTV (2.0% vs. 4.5%, p = 0.031), lower maximum chiasm dose (32 ± 11 Gy vs. 41 ± 15 Gy, p = 0.026), lower ipsilateral temporal-mandibular joint dose (D33: 41.4 Gy vs. 46.1 Gy, p = 0.016), lower mean ipsilateral middle ear dose (43 ± 9 Gy vs. 38 ± 10 Gy, p = 0.020) and a trend for lower optic nerve, temporal lobe, parotid, and oral cavity dose. In non-skull-base cases, doses to normal tissues were similar between the two plans. There was a reduction of 70% in MUs (486 ± 95 vs. 1614 ± 493, p < 0.001) and 73% in delivery times (3.0 ± 0.6 vs. 11.0 ± 3.3 min, p < 0.001) favoring VMAT. We conclude that VMAT appears to spare more normal tissues from high radiation dose for the tested skull-base tumors. Dosimetrically, both approaches were equivalent for non-skull-base tumor with VMAT using fewer MUs and shorter delivery time. PMID:22905805

  1. WE-F-16A-03: 3D Printer Application in Proton Therapy: A Novel Method to Deliver Passive-Scattering Proton Beams with a Fixed Range and Modulation for SRS and SRT

    SciTech Connect

    Ding, X; Witztum, A; Liang, X; Reiche, M; Lin, H; Teo, B; Yin, L; Fiene, J; McDonough, J; Kassaee, A

    2014-06-15

    Purpose: To present a novel technique to deliver passive-scattering proton beam with fixed range and modulation using a 3D printed patient-specific bolus for proton stereotactic radiosurgery and radiotherapy. Methods: A CIRS head phantom was used to simulate a patient with a small brain lesion. A custom bolus was created in the Eclipse Treatment Planning System (TPS) to compensate for the different water equivalent depths from the patient surface to the target from multiple beam directions. To simulate arc therapy, a plan was created on the initial CT using three passive-scattering proton beams with a fixed range and modulations irradiating from different angles. The DICOM-RT structure file of the bolus was exported from the TPS and converted to STL format for 3D printing. The phantom was rescanned with the printed custom bolus and head cup to verify the dose distribution comparing to the initial plan. EBT3 films were placed in the sagital plane of the target to verify the delivered dose distribution. The relative stopping power of the printing material(ABSplus-P430) was measured using the Zebra multi-plate ion chamber. Results: The relative stopping power of the 3D printing material, ABSplus-P430 was 1.05 which is almost water equivalent. The dose difference between verification CT and Initial CT is almost negligible. Film measurement also confirmed the accuracy for this new proton delivery technique. Conclusion: Our method using 3D printed range modifiers simplify the treatment delivery of multiple passive-scattering beams in treatment of small lesion in brain. This technique makes delivery of multiple beam more efficient and can be extended to allow arc therapy with proton beams. The ability to create and construct complex patient specific bolus structures provides a new dimension in creating optimized quality treatment plans not only for proton therapy but also for electron and photon therapy.

  2. Antenna Beam Coverage Concepts

    NASA Technical Reports Server (NTRS)

    Estabrook, Polly; Motamedi, Masoud

    1990-01-01

    The strawman Personal Access Satellite System (PASS) design calls for the use of a CONUS beam for transmission between the supplier and the satellite and for fixed beams for transmission between the basic personal terminal and the satellite. The satellite uses a 3 m main reflector for transmission at 20 GHz and a 2 m main reflector for reception at 30 GHz. There are several types of spot beams under consideration for the PASS system besides fixed beams. The beam pattern of a CONUS coverage switched beam is shown along with that of a scanning beam. A switched beam refers to one in which the signal from the satellite is connected alternatively to various feed horns. Scanning beams are taken to mean beams whose footprints are moved between contiguous regions in the beam's coverage area. The advantages and disadvantages of switched and/or scanning beams relative to fixed beams. The consequences of using switched/scanning in lieu of fixed beams in the PASS design and attempts are made to evaluate the listed advantages and disadvantages. Two uses of switched/scanning beams are examined. To illustrate the implications of switched beams use on PASS system design, operation at two beam scan rates is explored.

  3. 22. VIEW OF FIXED SPAN SUBSTRUCTURE, EAST SPAN, SHOWING CANTILEVEREDBEAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. VIEW OF FIXED SPAN SUBSTRUCTURE, EAST SPAN, SHOWING CANTILEVERED-BEAM SIDEWALK SUPPORTS, LONGITUDINAL GIRDER AND TRANSVERSE ROADBED BEAMS, LOOKING SOUTHEAST - Congress Street Bascule Bridge, Spanning Fort Point Channel at Congress Street, Boston, Suffolk County, MA

  4. Beam diagnostics

    SciTech Connect

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-08-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the {open_quotes}Booster{close_quotes} and {open_quotes}ATLAS{close_quotes} linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates.

  5. [Advantages of fixed combinations].

    PubMed

    Lachkar, Y

    2008-07-01

    Fixed combinations are indicated in the treatment of glaucoma and ocular hypertension when monotherapy does not sufficiently reduce IOP. Fixed combinations show better efficacy than the instillation of each separate component and are at least equivalent to the administration of both components in a separate association. They simplify treatment, increase compliance and quality of life, and decrease exposure to preservatives. Although they are less aggressive for patients when a new drug needs to be added, the use of fixed combinations should not decrease the follow-up. PMID:18957922

  6. Fixed target facility at the SSC

    SciTech Connect

    Loken, S.C.; Morfin, J.G.

    1985-01-01

    The question of whether a facility for fixed target physics should be provided at the SSC must be answered before the final technical design of the SSC can be completed, particularly if the eventual form of extraction would influence the magnet design. To this end, an enthusiastic group of experimentalists, theoreticians and accelerator specialists have studied this point. The accelerator physics issues were addressed by a group led by E. Colton whose report is contained in these proceedings. The physics addressable by fixed target was considered by many of the Physics area working groups and in particular by the Structure Function Group. This report is the summary of the working group which considered various SSC fixed target experiments and determined which types of beams and detectors would be required. 13 references, 5 figures.

  7. Beam-beam instability

    SciTech Connect

    Chao, A.W.

    1983-08-01

    The subject of beam-beam instability has been studied since the invention of the colliding beam storage rings. Today, with several colliding beam storage rings in operation, it is not yet fully understood and remains an outstanding problem for the storage ring designers. No doubt that good progress has been made over the years, but what we have at present is still rather primitive. It is perhaps possible to divide the beam-beam subject into two areas: one on luminosity optimization and another on the dynamics of the beam-beam interaction. The former area concerns mostly the design and operational features of a colliding beam storage ring, while the later concentrates on the experimental and theoretical aspects of the beam-beam interaction. Although both areas are of interest, our emphasis is on the second area only. In particular, we are most interested in the various possible mechanisms that cause the beam-beam instability.

  8. Fixing Dataset Search

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris

    2014-01-01

    Three current search engines are queried for ozone data at the GES DISC. The results range from sub-optimal to counter-intuitive. We propose a method to fix dataset search by implementing a robust relevancy ranking scheme. The relevancy ranking scheme is based on several heuristics culled from more than 20 years of helping users select datasets.

  9. Is there a role for fixed target heavy ion physics beyond RHIC startup?

    SciTech Connect

    Sandweiss, J.

    1995-07-15

    The interesting and important physics opportunities provided by AGS and CERN fixed target facilities will be far from exhausted by the time of RHIC turn on. Given the need for the AGS to provide heavy ion beams for injection into RHIC, the cost effectiveness of fixed target experimentation with AGS beams will be high. Examples of the physics are given.

  10. Fixed-target hadron production experiments

    NASA Astrophysics Data System (ADS)

    Popov, Boris A.

    2015-08-01

    Results from fixed-target hadroproduction experiments (HARP, MIPP, NA49 and NA61/SHINE) as well as their implications for cosmic ray and neutrino physics are reviewed. HARP measurements have been used for predictions of neutrino beams in K2K and MiniBooNE/SciBooNE experiments and are also being used to improve predictions of the muon yields in EAS and of the atmospheric neutrino fluxes as well as to help in the optimization of neutrino factory and super-beam designs. Recent measurements released by the NA61/SHINE experiment are of significant importance for a precise prediction of the J-PARC neutrino beam used for the T2K experiment and for interpretation of EAS data. These hadroproduction experiments provide also a large amount of input for validation and tuning of hadron production models in Monte-Carlo generators.

  11. Beauty and charm production at fixed-target experiments

    SciTech Connect

    Erik E. Gottschalk

    2003-12-10

    Fixed-target experiments continue to provide insights into the physics of particle production in strong interactions. The experiments are performed with different types of beam particles of varying energies, and many different target materials. Studies of beauty and charm production are of particular interest, since experimental results can be compared to perturbative QCD calculations. It is in this context that recent results from fixed-target experiments on beauty and charm production will be reviewed.

  12. Fixed and Sunk Costs Revisited.

    ERIC Educational Resources Information Center

    Wang, X. Henry; Yang, Bill Z.

    2001-01-01

    Attempts to clarify the concepts of, and the link between, fixed costs and sunk costs. Argues that the root of confusion is the inconsistency in defining the term fixed costs. Consistently defines fixed and sunk costs, and describes how instructors must teach under these definitions. (RLH)

  13. Review of calorimetry in Fermilab fixed-target experiments

    SciTech Connect

    Crisler, M.B.

    1995-04-01

    The fixed-target program at Fermilab comprises as many as thirteen simultaneous experiments in ten separate beamlines using beams of primary protons, pions, kaons, electrons, neutrinos, and muons. The fixed target beamlines were last in operation in the latter half of 1991, shutting down in 1992. The next fixed target run is scheduled for early 1996. This article describes some of the wide variety of calorimetric devices that were in use in the past run or to be used in the coming run. Special attention is devoted to the new devices currently under construction.

  14. Apparatus for fixing latency

    DOEpatents

    Hall, David R.; Bartholomew, David B.; Moon, Justin; Koehler, Roger O.

    2009-09-08

    An apparatus for fixing computational latency within a deterministic region on a network comprises a network interface modem, a high priority module and at least one deterministic peripheral device. The network interface modem is in communication with the network. The high priority module is in communication with the network interface modem. The at least one deterministic peripheral device is connected to the high priority module. The high priority module comprises a packet assembler/disassembler, and hardware for performing at least one operation. Also disclosed is an apparatus for executing at least one instruction on a downhole device within a deterministic region, the apparatus comprising a control device, a downhole network, and a downhole device. The control device is near the surface of a downhole tool string. The downhole network is integrated into the tool string. The downhole device is in communication with the downhole network.

  15. [Fixed-dose combination].

    PubMed

    Nagai, Yoshio

    2015-03-01

    Many patients with type 2 diabetes mellitus(T2DM) do not achieve satisfactory glycemic control by monotherapy alone, and often require multiple oral hypoglycemic agents (OHAs). Combining OHAs with complementary mechanisms of action is fundamental to the management of T2DM. Fixed-dose combination therapy(FDC) offers a method of simplifying complex regimens. Efficacy and tolerability appear to be similar between FDC and treatment with individual agents. In addition, FDC can enhance adherence and improved adherence may result in improved glycemic control. Four FDC agents are available in Japan: pioglitazone-glimepiride, pioglitazone-metformin, pioglitazone-alogliptin, and voglibose-mitiglinide. In this review, the advantages and disadvantages of these four combinations are identified and discussed. PMID:25812374

  16. Fixed Access Network Sharing

    NASA Astrophysics Data System (ADS)

    Cornaglia, Bruno; Young, Gavin; Marchetta, Antonio

    2015-12-01

    Fixed broadband network deployments are moving inexorably to the use of Next Generation Access (NGA) technologies and architectures. These NGA deployments involve building fiber infrastructure increasingly closer to the customer in order to increase the proportion of fiber on the customer's access connection (Fibre-To-The-Home/Building/Door/Cabinet… i.e. FTTx). This increases the speed of services that can be sold and will be increasingly required to meet the demands of new generations of video services as we evolve from HDTV to "Ultra-HD TV" with 4k and 8k lines of video resolution. However, building fiber access networks is a costly endeavor. It requires significant capital in order to cover any significant geographic coverage. Hence many companies are forming partnerships and joint-ventures in order to share the NGA network construction costs. One form of such a partnership involves two companies agreeing to each build to cover a certain geographic area and then "cross-selling" NGA products to each other in order to access customers within their partner's footprint (NGA coverage area). This is tantamount to a bi-lateral wholesale partnership. The concept of Fixed Access Network Sharing (FANS) is to address the possibility of sharing infrastructure with a high degree of flexibility for all network operators involved. By providing greater configuration control over the NGA network infrastructure, the service provider has a greater ability to define the network and hence to define their product capabilities at the active layer. This gives the service provider partners greater product development autonomy plus the ability to differentiate from each other at the active network layer.

  17. Ion beam thruster shield

    NASA Technical Reports Server (NTRS)

    Power, J. L. (Inventor)

    1976-01-01

    An ion thruster beam shield is provided that comprises a cylindrical housing that extends downstream from the ion thruster and a plurality of annular vanes which are spaced along the length of the housing, and extend inwardly from the interior wall of the housing. The shield intercepts and stops all charge exchange and beam ions, neutral propellant, and sputter products formed due to the interaction of beam and shield emanating from the ion thruster outside of a fixed conical angle from the thruster axis. Further, the shield prevents the sputter products formed during the operation of the engine from escaping the interior volume of the shield.

  18. A Beam Transport and Loss simulation with electrostatic beam separator

    NASA Astrophysics Data System (ADS)

    Yang, Ming-Jen

    1997-05-01

    Eletrostatic beam separator (septa) string is used in the Fermilab fixed target program for slow extraction from Tevatron and for dividing the beam to different experimental area. The loss from beam interaction with the dividing wire plane of the septa is used to determine the alignment of individual septum within a string of many. The interpretation of the real life signal registered at the loss monitors is not always straight forward. A simulation is being done to model the beam split through septa string and the loss pattern at exisiting beam loss monitor locations. This should lead to a better understanding of the signal and help in the alignment operation.

  19. Portable walking beam pump jack

    SciTech Connect

    Laney, R.N.

    1986-02-25

    This patent describes a portable walking beam pump jack for use in pumping liquids from an oil well. This jack consists of: an elongated frame having a longitudinal axis and front and rear ends, the frame also including first and second support seats; a towing receptacle, an axle connected transversely across the frame; ground engaging wheels connected to the axle for supporting the frame for rolling transportation; stabilizing means for securing the frame with respect to a ground location; a walking beam having a first end, a midportion and a second end, the second end being adapted for connection to a pumping rod; an engine mounted on the frame; a pair of arms counterweighted for balancing a pumping rod connected to the walking beam, a drive yoke, a support assembly foldably mounted on the frame and upon which the midportion of the walking beam is pivotally connected, the support assembly the arms and the drive yoke being foldable together, from a first, fixed position in which the walking beam arms and yoke are supported in a raised position for rocking in a pumping motion to a second, fixed position disposed downwardly and forwardly from the first fixed position and in which the walking beam arms and yoke are held in a lowered position for transportation; a front support and a hydraulic cylinder connected between the frame and the support assembly for moving the support assembly between the first, fixed position and the second fixed position.

  20. Magnetic beam position monitor

    SciTech Connect

    Varfolomeev, A.A.; Ivanchenkov, S.N.; Khlebnikov, A.S.

    1995-12-31

    Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends on the steel yoke dimensions. The detector sensitivity is equal to 1 Gauss/mm for the conditions adequate to the FOM-FEM project.

  1. Main Ring bunch spreaders: Past, 1987/1988 fixed target run, and proposed future

    SciTech Connect

    Jackson, G.P.

    1989-02-26

    During the last 1987--1988 fixed target running period beam intensity was limited many times by coherent instabilities in both the Main Ring and in the Tevatron. The intensity thresholds for instabilities are generally inversely proportional to the proton bunch length. Since fixed target operations are insensitive to the longitudinal phase space emittance of the beam, bunch spreaders are employed to increase this emittance, and hence the bunch length. As a result, more beam intensity can be delivered to the fixed target experiments. This paper starts with a short history behind the old Main Ring bunch spreader. After discussing the physics of stimulated emittance growth, the design and performance of the 1987--1988 fixed target run Main Ring bunch spreader is discussed. Finally, designs of improved Main Ring and Tevatron bunch spreaders for the next fixed target run are proposed. 23 figs.

  2. Directionally positionable neutron beam

    SciTech Connect

    Bumgardner, H.M.; Dance, W.E.

    1981-11-10

    Disclosed is apparatus for forming and directionally positioning a neutron beam. The apparatus includes an enclosed housing rotatable about a first axis with a neutron source axially positionable on the axis of rotation of the enclosed housing but rotationally fixed with respect to the housing. The rotatable housing is carried by a vertically positionable arm carried on a mobile transport. A collimator is supported by the rotatable housing and projects into the housing to orientationally position its inlet window at an adjustably fixed axial and radial spacing from the neutron source so that rotation of the enclosed housing causes the inlet window to rotate about a circle which is a fixed axial distance from the neutron source and has the axis of rotation of the housing as its center.

  3. Flexural Vibrations of Circular Beams

    NASA Astrophysics Data System (ADS)

    Silverman, I. K.

    1998-03-01

    For circular cylindrical beams, the Timoshenko theory, which includes shear and rotary effects, can be applied by introducing a constantK‧=0·9. The study presented here takes into account the actual configuration and thus makes it an integral part of the analysis. A variational approach previously used [7] is followed. A simplification of the three-dimensional problem is obtained using the inverse method due to St. Venant. A biquadratic equation yields numerical results for the natural frequencies of the first three modes for the following cases: simply supported, fixed-fixed, free-free and fixed-free.

  4. Funding human services: fixed utility versus fixed budget.

    PubMed

    McCready, D J; Rahn, S L

    1986-01-01

    It is argued in this paper that government allocations for human services based on inputs rather than outcomes, reduce efficiency in social and health service provision. An alternative system of budgeting or contracting on the basis of cost-per-closed case and case outcome is discussed. An interdependency between fixed budget and fixed utility models of allocation is affirmed. The locus of decision-making for operationalizing this interdependency is seen as the program and budget review panel to which operating agencies and government departments must submit financial and program accounting information from year to year. In isolation, the fixed budget approach degenerates into routine allocation or contract renewal with a focus on such input and output variables as volume of service and unit cost, and the fixed utility approach, into political stalemate. Simulated examples are given to demonstrate how allocation on the basis of inputs and outputs alone provides an incentive to inefficiency, and a fixed utility orientation to efficiency. PMID:10311890

  5. Evidence of the big fix

    NASA Astrophysics Data System (ADS)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2014-06-01

    We give an evidence of the Big Fix. The theory of wormholes and multiverse suggests that the parameters of the Standard Model are fixed in such a way that the total entropy at the late stage of the universe is maximized, which we call the maximum entropy principle. In this paper, we discuss how it can be confirmed by the experimental data, and we show that it is indeed true for the Higgs vacuum expectation value vh. We assume that the baryon number is produced by the sphaleron process, and that the current quark masses, the gauge couplings and the Higgs self-coupling are fixed when we vary vh. It turns out that the existence of the atomic nuclei plays a crucial role to maximize the entropy. This is reminiscent of the anthropic principle, however it is required by the fundamental law in our case.

  6. Full and partial gauge fixing

    SciTech Connect

    Shirzad, A.

    2007-08-15

    Gauge fixing may be done in different ways. We show that using the chain structure to describe a constrained system enables us to use either a full gauge, in which all gauged degrees of freedom are determined, or a partial gauge, in which some first class constraints remain as subsidiary conditions to be imposed on the solutions of the equations of motion. We also show that the number of constants of motion depends on the level in a constraint chain in which the gauge fixing condition is imposed. The relativistic point particle, electromagnetism, and the Polyakov string are discussed as examples and full or partial gauges are distinguished.

  7. The Double Fixed Charge Membrane

    PubMed Central

    Coster, H. G. L.

    1973-01-01

    An analysis is made of the AC characteristics of a membrane consisting of two fixed charge regions of opposite sign, in contact. It is shown that the equivalent parallel capacitance and conductance of such a membrane undergo a strong dispersion at low frequencies. The dielectric dispersion is a result of polarization effects in the diffusion of coions in each of the two fixed charge lattices. This, at low frequencies, gives rise to a very large diffusion capacitance. The form of the dispersion characteristics is very similar to those observed for synthetic-fused anion-cation membranes and various cellular membranes. PMID:4702011

  8. Spin-exchange relaxation-free magnetometer with nearly parallel pump and probe beams

    NASA Astrophysics Data System (ADS)

    Karaulanov, Todor; Savukov, Igor; Kim, Young Jin

    2016-05-01

    We constructed a spin-exchange relaxation-free (SERF) magnetometer with a small angle between the pump and probe beams facilitating a multi-channel design with a flat pancake cell. This configuration provides almost complete overlap of the beams in the cell, and prevents the pump beam from entering the probe detection channel. By coupling the lasers in multi-mode fibers, without an optical isolator or field modulation, we demonstrate a sensitivity of 10 f T/\\sqrt{\\text{Hz}} for frequencies between 10 Hz and 100 Hz. In addition to the experimental study of sensitivity, we present a theoretical analysis of SERF magnetometer response to magnetic fields for small-angle and parallel-beam configurations, and show that at optimal DC offset fields the magnetometer response is comparable to that in the orthogonal-beam configuration. Based on the analysis, we also derive fundamental and probe-limited sensitivities for the arbitrary non-orthogonal geometry. The expected practical and fundamental sensitivities are of the same order as those in the orthogonal geometry. We anticipate that our design will be useful for magnetoencephalography (MEG) and magnetocardiography (MCG) applications.

  9. Spin-exchange relaxation-free magnetometer with nearly parallel pump and probe beams

    DOE PAGESBeta

    Karaulanov, Todor; Savukov, Igor; Kim, Young Jin

    2016-03-22

    We constructed a spin-exchange relaxation-free (SERF) magnetometer with a small angle between the pump and probe beams facilitating a multi-channel design with a flat pancake cell. This configuration provides almost complete overlap of the beams in the cell, and prevents the pump beam from entering the probe detection channel. By coupling the lasers in multi-mode fibers, without an optical isolator or field modulation, we demonstrate a sensitivity of 10 fTmore » $$/\\sqrt{\\text{Hz}}$$ for frequencies between 10 Hz and 100 Hz. In addition to the experimental study of sensitivity, we present a theoretical analysis of SERF magnetometer response to magnetic fields for small-angle and parallel-beam configurations, and show that at optimal DC offset fields the magnetometer response is comparable to that in the orthogonal-beam configuration. Based on the analysis, we also derive fundamental and probe-limited sensitivities for the arbitrary non-orthogonal geometry. The expected practical and fundamental sensitivities are of the same order as those in the orthogonal geometry. As a result, we anticipate that our design will be useful for magnetoencephalography (MEG) and magnetocardiography (MCG) applications.« less

  10. Fixed Costs and Hours Constraints

    ERIC Educational Resources Information Center

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  11. Variable delivery, fixed displacement pump

    SciTech Connect

    Sommars, Mark F.

    2001-01-01

    A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

  12. Beam splitter and method for generating equal optical path length beams

    DOEpatents

    Qian, Shinan; Takacs, Peter

    2003-08-26

    The present invention is a beam splitter for splitting an incident beam into first and second beams so that the first and second beams have a fixed separation and are parallel upon exiting. The beam splitter includes a first prism, a second prism, and a film located between the prisms. The first prism is defined by a first thickness and a first perimeter which has a first major base. The second prism is defined by a second thickness and a second perimeter which has a second major base. The film is located between the first major base and the second major base for splitting the incident beam into the first and second beams. The first and second perimeters are right angle trapezoidal shaped. The beam splitter is configured for generating equal optical path length beams.

  13. Genetic and structural analysis of the Rhizobium meliloti fixA, fixB, fixC, and fixX genes.

    PubMed Central

    Earl, C D; Ronson, C W; Ausubel, F M

    1987-01-01

    The fixA, fixB, fixC, and fixX genes of Rhizobium meliloti 1021 constitute an operon and are required for nitrogen fixation in alfalfa nodules. DNA homologous to the R. meliloti fixABC genes is present in all other Rhizobium and Bradyrhizobium species examined, but fixABC-homologous sequences were found in only one free-living diazotroph, Azotobacter vinelandii. To determine whether the fixABCX genes share sequence homology with any of the 17 Klebsiella pneumoniae nif genes, we determined the entire nucleotide sequence of the fixA, fixB, fixC, and fixX genes and defined four open reading frames that code for polypeptides of molecular weights 31,146, 37,786, 47,288, and 10,937, respectively. Neither DNA nor amino acid sequence homology to the R. meliloti fixA, -B, -C, and -X genes was found in the K. pneumoniae nif operon. The fixX gene contains a cluster of cysteine residues characteristic of ferredoxins and is highly homologous to an Azotobacter ferredoxin which has been shown to donate electrons to nitrogenase. The fixABC operon contains a promoter region that is highly homologous to other nifA-activated promoters. We also found a duplication of the 5' end of the fixABCX operon; a 250-bp region located 520 bp upstream of the fixABCX promoter bears more than 65% homology to the 5' end of the transcribed region, including the first 32 codons of fixA. Images PMID:3029021

  14. Multiple Fixed-Point Cell

    NASA Astrophysics Data System (ADS)

    Edler, F.; Ederer, P.

    2014-07-01

    The paper describes the construction and investigation of multiple fixed-point cells usable for the calibration of thermocouples at temperatures above 1100 C. These fixed-point cells made of pure graphite are characterized by a simple construction as well as by a flexible application. The cylindrical basic mount is equipped with a central hole for the insertion of a thermocouple, and with eight drill holes containing exchangeable cartridges which surround the central bore axially symmetrically. The cartridges are filled with different metal-carbon (Me-C) eutectics: cobalt-carbon (Co-C), nickel-carbon (Ni-C), palladium-carbon (Pd-C), and rhodium-carbon (Rh-C). The melting temperatures of the different Me-C eutectics of the cartridges were compared to the melting temperatures of commonly used Me-C eutectic fixed-point cells of the Physikalisch-Technische Bundesanstalt by using a Pt/Pd thermocouple (Co-C, Ni-C) and Type B thermocouples (Pd-C, Rh-C). The uncertainties () of the emfs measured at the inflection points of the melting curves are in the order of a few V which correspond to temperature equivalents between 0.3 K and 0.6 K. Furthermore, the difference between the melting temperatures of the Co-C and Ni-C cartridges was found to be 4.2 K by using simultaneously two sets of four cartridges filled with the two materials and placed alternately in the eight outer holes of one basic mount.

  15. 29 CFR 1917.118 - Fixed ladders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Fixed ladders. 1917.118 Section 1917.118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.118 Fixed ladders. (a) Scope and applicability. This section applies to all fixed ladders...

  16. 29 CFR 1917.118 - Fixed ladders.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Fixed ladders. 1917.118 Section 1917.118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.118 Fixed ladders. (a) Scope and applicability. This section applies to all fixed ladders...

  17. 29 CFR 1917.120 - Fixed stairways.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Fixed stairways. 1917.120 Section 1917.120 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.120 Fixed stairways. (a) Definition. “Fixed...

  18. 29 CFR 1917.120 - Fixed stairways.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Fixed stairways. 1917.120 Section 1917.120 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) MARINE TERMINALS Terminal Facilities § 1917.120 Fixed stairways. (a) Definition. “Fixed...

  19. Optical Tweezers for Sample Fixing in Micro-Diffraction Experiments

    SciTech Connect

    Amenitsch, H.; Rappolt, M.; Sartori, B.; Laggner, P.; Cojoc, D.; Ferrari, E.; Garbin, V.; Di Fabrizio, E.; Burghammer, M.; Riekel, Ch.

    2007-01-19

    In order to manipulate, characterize and measure the micro-diffraction of individual structural elements down to single phospholipid liposomes we have been using optical tweezers (OT) combined with an imaging microscope. We were able to install the OT system at the microfocus beamline ID13 at the ESRF and trap clusters of about 50 multi-lamellar liposomes (< 10 {mu}m large cluster). Further we have performed a scanning diffraction experiment with a 1 micrometer beam to demonstrate the fixing capabilities and to confirm the size of the liposome cluster by X-ray diffraction.

  20. Simple Fixed Functional Space Maintainer

    PubMed Central

    Sarawgi, Aditi; Marwah, Nikhil; Gumber, Parvind; Dutta, Samir

    2014-01-01

    ABSTRACT% Premature loss of a primary tooth is one of the most common etiology for malocclusion. Space maintainers are employed to prevent this complication. In anterior region, esthetics is an important concern along with function and space management. Fiber-reinforced composite (FRC) retained space maintainer solves all these purposes ef ficiently and ef fectively. In addition, the technique is simple and the appliance is very comfortable inside the oral cavity. Here is a case of premature loss of anterior primary tooth which was replaced by FRC retained esthetic functional space maintainer. The appliance was found to be functioning satisfactorily inside the oral cavity till the last visit (1 Year). How to cite this article: Goenka P, Sarawgi A, Marwah N, Gumber P, Dutta S. Simple Fixed Functional Space Maintainer. Int J Clin Pediatr Dent 2014;7(3):225-228. PMID:25709309

  1. Fixed drug eruptions with modafinil

    PubMed Central

    Ghoshal, Loknath; Sinha, Mausumi

    2015-01-01

    Modafinil is a psychostimulant drug, which has been approved by the US Food and Drug Administration for the treatment of narcolepsy associated excessive daytime sleepiness, sleep disorder related to shift work, and obstructive sleep apnea syndrome. However, presently it is being used as a lifestyle medicine; in India, it has been misused as an “over the counter” drug. Modafinil is known to have several cutaneous side effects. Fixed drug eruption (FDE) is a distinctive drug induced reaction pattern characterized by recurrence of eruption at the same site of the skin or mucous membrane with repeated systemic administration. Only two case reports exist in the literature describing modafinil induced FDE until date. Here, we report two similar cases. The increasing use of this class of drug amongst the medical personnel might be posing a threat to the proper use and encouraging subsequent abuse. There might be a considerable population using these drugs unaware of the possible adverse effects. Authorities should be more alert regarding the sale and distribution of such medicines. PMID:25878389

  2. The fixed target experiment for studies of baryonic matter at the Nuclotron (BM@N)

    NASA Astrophysics Data System (ADS)

    Kapishin, Mikhail

    2016-08-01

    BM@N (Baryonic Matter at Nuclotron) is the first experiment to be realized at the accelerator complex of NICA-Nuclotron. The aim of the BM@N experiment is to study interactions of relativistic heavy-ion beams with fixed targets. The BM@N setup, results of Monte Carlo simulations and the BM@N experimental program are presented.

  3. Beam tuning

    SciTech Connect

    Pardo, R.C.; Zinkann, G.P.

    1995-08-01

    A program for configuring the linac, based on previously run configurations for any desired beam was used during the past year. This program uses only a small number of empirical tunes to scale resonator fields to properly accelerate a beam with a different charge-to-mass (q/A) ratio from the original tune configuration. The program worked very well for the PII linac section where we can easily match a new beam`s arrival phase and velocity to the tuned value. It was also fairly successful for the Booster and ATLAS sections of the linac, but not as successful as for the PII linac. Most of the problems are associated with setting the beam arrival time correctly for each major linac section. This problem is being addressed with the development of the capacitive pickup beam phase monitor discussed above. During the next year we expect to improve our ability to quickly configure the linac for new beams and reduce the time required for linac tuning. Already the time required for linac tuning as a percentage of research hours has decreased from 22% in FY 1993 to 15% in the first quarter of FY 1995.

  4. Optics of ion beams for the neutral beam injection system on HL-2A Tokamak

    SciTech Connect

    Zou, G. Q.; Lei, G. J.; Cao, J. Y.; Duan, X. R.

    2012-07-15

    The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage ({approx}100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak.

  5. Optics of ion beams for the neutral beam injection system on HL-2A Tokamak.

    PubMed

    Zou, G Q; Lei, G J; Cao, J Y; Duan, X R

    2012-07-01

    The ion beam optics for the neutral beam injection system on HL-2A Tokomak is studied by two- dimensional numerical simulation program firstly, where the emitting surface is taken at 100 Debye lengths from the plasma electrode. The mathematical formulation, computation techniques are described. Typical ion orbits, equipotential contours, and emittance diagram are shown. For a fixed geometry electrode, the effect of plasma density, plasma potential and plasma electron temperature on ion beam optics is examined, and the calculation reliability is confirmed by experimental results. In order to improve ion beam optics, the application of a small pre-acceleration voltage (∼100 V) between the plasma electrode and the arc discharge anode is reasonable, and a lower plasma electron temperature is desired. The results allow optimization of the ion beam optics in the neutral beam injection system on HL-2A Tokomak and provide guidelines for designing future neutral beam injection system on HL-2M Tokomak. PMID:22852685

  6. Experimental observations and theoretical models for beam-beam phenomena

    SciTech Connect

    Kheifets, S.

    1981-03-01

    The beam-beam interaction in storage rings exhibits all the characteristics of nonintegrable dynamical systems. Here one finds all kinds of resonances, closed orbits, stable and unstable fixed points, stochastic layers, chaotic behavior, diffusion, etc. The storage ring itself being an expensive device nevertheless while constructed and put into operation presents a good opportunity of experimentally studying the long-time behavior of both conservative (proton machines) and nonconservative (electron machines) dynamical systems - the number of bunch-bunch interactions routinely reaches values of 10/sup 10/-10/sup 11/ and could be increased by decreasing the beam current. At the same time the beam-beam interaction puts practical limits for the yield of the storage ring. This phenomenon not only determines the design value of main storage ring parameters (luminosity, space charge parameters, beam current), but also in fact prevents many of the existing storage rings from achieving design parameters. Hence, the problem has great practical importance along with its enormous theoretical interest. A brief overview of the problem is presented.

  7. Observations and open questions in beam-beam interactions

    SciTech Connect

    Sen, Tanaji; /Fermilab

    2010-08-01

    The first of the hadron colliders, ISR, started operation in 1970. In the following years, the hadron colliders to follow were the SPS (started 1980), the Tevatron (started 1987 first as a fixed target machine), RHIC (started 2000) and most recently the LHC, which started in 2008. HERA was a hybrid that collided electrons and protons. All of these accelerators had or have their performance limited by the effects of the beam-beam interactions. That has also been true for the electron-positron colliders such as LEP, CESR, KEKB and PEPII. In this article I will discuss how the beam-beam limitations arose in some of these machines. The discussion will be focused on common themes that span the different colliders. I will mostly discuss the hadron colliders but sometimes discuss the lepton colliders where relevant. Only a handful of common accelerator physics topics are chosen here, the list is not meant to be exhaustive. A comparative review of beam-beam performance in the ISR, SPS and Tevatron (ca 1989) can be found in reference. Table 1 shows the relevant parameters of colliders (excluding the LHC), which have accelerated protons.

  8. Statistical analysis of fixed income market

    NASA Astrophysics Data System (ADS)

    Bernaschi, Massimo; Grilli, Luca; Vergni, Davide

    2002-05-01

    We present cross and time series analysis of price fluctuations in the US Treasury fixed income market. Bonds have been classified according to a suitable metric based on the correlation among them. The classification shows how the correlation among fixed income securities depends strongly on their maturity. We study also the structure of price fluctuations for single time series.

  9. Fixed-Response Questions with a Difference.

    ERIC Educational Resources Information Center

    Johnstone, Alex H.; Ambusaidi, Abdullah

    2002-01-01

    Offers three types of fixed-response questions that are designed to overcome drawbacks appearing in the conventional forms of fixed-response questions such as not allowing the examiner to investigate reasoning, background, or prevent guessing. (Contains 14 references.) (Author/YDS)

  10. 29 CFR 1910.27 - Fixed ladders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...). For fixed ladders consisting of wood side rails and wood rungs or cleats, used at a pitch in the range..., cleats, and steps shall be free of splinters, sharp edges, burrs, or projections which may be a hazard... of fixed ladders shall be considered to come in the range of 75 degrees and 90 degrees with...

  11. Negotiating a Fixed-Unit Price Contract.

    ERIC Educational Resources Information Center

    Pasquale, Mathew; Morrison, Wade

    1986-01-01

    Discusses the concept of "fixed-unit price contracting," an arrangement that is becoming popular with private industry councils (PICs). Guidelines include (1) find out as much as you can about the PIC's requirements; (2) figure out whether you can meet the PIC's requirements; and (3) keep in mind that most elements of a fixed-unit price contract…

  12. Gaining Insight into an Organization's Fixed Assets.

    ERIC Educational Resources Information Center

    Hardy, Elisabet

    2003-01-01

    Discusses issues related to school district implementation of June 2001 Government Accounting Standards Board (GASB) Statement 34 designed to change how schools report fixed assets. Includes planning for GASB implementation, conducting fixed-asset inventories, and making time for GASB reporting. (PKP)

  13. 78 FR 20705 - Fixed Income Roundtable

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Fixed Income Roundtable AGENCY: Securities and Exchange Commission. ACTION: Notice of roundtable..., efficiency, and other aspects of fixed income markets. The roundtable will focus on the municipal...

  14. Beam-beam deflection and signature curves for elliptic beams

    SciTech Connect

    Ziemann, V.

    1990-10-22

    In this note we will present closed expressions for the beam-beam deflection angle for arbitrary elliptic beams including tilt. From these expressions signature curves, i.e., systematic deviations from the round beam deflection curve due to ellipticity or tilt are derived. In the course of the presentation we will prove that it is generally impossible to infer individual beam sizes from beam-beam deflection scans. 3 refs., 2 figs.

  15. Merged Beams Studies for Astrobiology

    NASA Astrophysics Data System (ADS)

    Savin, Daniel Wolf; O'Connor, Aodh P.; de Ruette, Nathalie; Miller, Kenneth; Stuetzel, Julia; Urbain, Xavier

    2015-08-01

    The chain of chemical reactions leading towards life is thought to begin in molecular clouds when atomic C and O are fixed into molecules. Reactions of neutral C with H3+ is one of the first steps in the gas-phase chemistry leading to the formation of complex organic molecules. Water, believed to be vital for life, can form via a chain of gas-phase reactions that begin with neutral O reacting with H3+. Uncertainties in the rate coefficient for these reactions hinder our ability to understand the first links in the chemical chain leading towards life. Theory provides little insight as fully quantum mechanical calculations for reactions involving four or more atoms are beyond current capabilities. Experimental data are sparse due to the challenge of producing sufficiently intense and well-characterized beams of neutral atoms.We have developed a novel merged-beam apparatus to study reactions of neutral atoms with molecular ions at the low collision energies relevant for molecular clouds. Photo-detachment of keV-energy atomic anion beams is used to produce beams of neutral C and O. A velocity-matched H3+ beam is then merged with the neutrals. The merged-beams method allows us to achieve kinetic temperatures below 30 K. Using our results, we are able to generate thermal rate coefficients for use in chemical models of molecular clouds.

  16. Optimal mixing and optimal stirring for fixed energy, fixed power, or fixed palenstrophy flows

    NASA Astrophysics Data System (ADS)

    Lunasin, Evelyn; Lin, Zhi; Novikov, Alexei; Mazzucato, Anna; Doering, Charles R.

    2012-11-01

    We consider passive scalar mixing by a prescribed divergence-free velocity vector field in a periodic box and address the following question: Starting from a given initial inhomogeneous distribution of passive tracers, and given a certain energy budget, power budget, or finite palenstrophy budget, what incompressible flow field best mixes the scalar quantity? We focus on the optimal stirring strategy recently proposed by Lin et al. ["Optimal stirring strategies for passive scalar mixing," J. Fluid Mech. 675, 465 (2011)], 10.1017/S0022112011000292 that determines the flow field that instantaneously maximizes the depletion of the H-1 mix-norm. In this work, we bridge some of the gap between the best available a priori analysis and simulation results. After recalling some previous analysis, we present an explicit example demonstrating finite-time perfect mixing with a finite energy constraint on the stirring flow. On the other hand, using a recent result by Wirosoetisno et al. ["Long time stability of a classical efficient scheme for two dimensional Navier-Stokes equations," SIAM J. Numer. Anal. 50(1), 126-150 (2012)], 10.1137/110834901 we establish that the H-1 mix-norm decays at most exponentially in time if the two-dimensional incompressible flow is constrained to have constant palenstrophy. Finite-time perfect mixing is thus ruled out when too much cost is incurred by small scale structures in the stirring. Direct numerical simulations in two dimensions suggest the impossibility of finite-time perfect mixing for flows with fixed power constraint and we conjecture an exponential lower bound on the H-1 mix-norm in this case. We also discuss some related problems from other areas of analysis that are similarly suggestive of an exponential lower bound for the H-1 mix-norm.

  17. Scintillation characterization for multiple incoherent uplink Gaussian beams

    NASA Astrophysics Data System (ADS)

    Wu, Wu-Ming; Ning, Yu; Ma, Yan-Xing; Xi, Fen-Jie; Xu, Xiao-Jun

    2014-09-01

    By means of numerical simulations, we analyze the scintillation characterization for multiple incoherent uplink Gaussian beams under weak fluctuations cases. Because truly independent beams are difficult to create, we present a more general but approximate model for the multiple of beams traveling through partially correlated paths. This model compares with wave-optics simulations and highlights the reduced correlation coefficient as the beam separation is increased. The scintillation index of three and six incoherent uplink Gaussian beams is also induced. The result shows that the scintillation index decreases with the increase of beams amount and beam separation. When the beams amount and strength of atmospheric turbulence are fixed, the reduction of scintillation index is affected by the ratio of beams separation and the Fried length. The corresponding physical mechanisms for the results are discussed.

  18. Exploring portals to a hidden sector through fixed targets

    SciTech Connect

    Batell, Brian; Pospelov, Maxim; Ritz, Adam

    2009-11-01

    We discuss the sensitivity of neutrino experiments at the luminosity frontier to generic hidden sectors containing new (sub)-GeV neutral states. The weak interaction of these states with the standard model can be efficiently probed through all of the allowed renormalizable 'portals' (in the Higgs, vector, and neutrino sectors) at fixed target proton beam facilities, with complementary sensitivity to colliders. We concentrate on the kinetic-mixing vector portal, and show that certain regions of the parameter space for a new U(1){sub S} gauge sector with long-lived sub-GeV mass states decaying to standard model leptons are already severely constrained by the data sets at LSND, MiniBooNE, and NuMI/MINOS. Furthermore, scenarios in which portals allow access to stable neutral particles, such as MeV-scale dark matter, generally predict that the neutrino beam is accompanied by a 'dark matter beam', observable through neutral-current-like interactions in the detector. As a consequence, we show that the LSND electron recoil event sample currently provides the most stringent direct constraint on MeV-scale dark matter models.

  19. Beam loss

    NASA Astrophysics Data System (ADS)

    VanGinneken, A.; Edwards, D.; Harrison, M.

    1989-04-01

    This paper presents results from simulations of beam losses during the operation of a superconducting accelerator. The calculations use a combination of hadron/electromagnetic cascade plus elastic scattering codes with accelerator tracking routines. These calculations have been used in conjunction with the design of the Fermilab Tevatron. First accelerator geometry is described. The rest of the paper discusses a detailed attempt to simulate a fast extraction cycle, essentially in chronological order. Beginning with an unperturbed beam, the simulation generates proton phase-space distributions incident on the electrostatic septum. These interact either elastically or inelastically with the septum wires, and the products of these interactions are traced through the machine. Where these leave the accelerator, energy deposition levels in the magnets are calculated together with the projected response of the beam-loss monitors in this region. Finally, results of the calculation are compared with experimental data. (AIP)

  20. [FIXED COMBINATION ATORVASTATIN-EZETIMIBE (ATOZET®)].

    PubMed

    Scheen, A J

    2016-01-01

    Cardiovascular prevention in subjects at high or very high risk requires a drastic reduction in LDL cholesterol according to the concept "the lower, the better". The combination of an inhibitor of cholesterol synthesis and a selective inhibitor of intestinal absorption results in a complementary and synergistic LDL-lowering activity. Besides a first fixed combination ezetimibe-simvastatin (Inegy®), a new fixed combination is presented, Atozet® that combines atorvastatin and ezetimibe. Because atorvastatin is more potent than simvastatin, this novel fixed combination should facilitate reaching therapeutic goals in terms of LDL cholesterol amongst patients with severe hypercholesterolaemia and/or at high or very high cardiovascular risk. PMID:26983314

  1. The 1994 Fermilab Fixed Target Program

    SciTech Connect

    Conrad, J. |

    1994-11-01

    This paper highlights the results of the Fermilab Fixed Target Program that were announced between October, 1993 and October, 1994. These results are drawn from 18 experiments that took data in the 1985, 1987 and 1990/91 fixed target running periods. For this discussion, the Fermilab Fixed Target Program is divided into 5 major topics: hadron structure, precision electroweak measurements, heavy quark production, polarization and magnetic moments, and searches for new phenomena. However, it should be noted that most experiments span several subtopics. Also, measurements within each subtopic often affect the results in other subtopics. For example, parton distributions from hadron structure measurements are used in the studies of heavy quark production.

  2. Updraft Fixed Bed Gasification Aspen Plus Model

    Energy Science and Technology Software Center (ESTSC)

    2007-09-27

    The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability ofmore » the process model.« less

  3. Improving Plating by Use of Intense Acoustic Beams

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Denofrio, Charles

    2003-01-01

    An improved method of selective plating of metals and possibly other materials involves the use of directed high-intensity acoustic beams. The beams, typically in the ultrasonic frequency range, can be generated by fixed-focus transducers (see figure) or by phased arrays of transducers excited, variously, by continuous waves, tone bursts, or single pulses. The nonlinear effects produced by these beams are used to alter plating processes in ways that are advantageous.

  4. Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators

    NASA Astrophysics Data System (ADS)

    Edmonds, C. S.; Gratus, J.; Hock, K. M.; Machida, S.; Muratori, B. D.; Torromé, R. G.; Wolski, A.

    2014-05-01

    In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA.

  5. New Fixed-Target Experiments to Search for Dark Gauge Forces

    SciTech Connect

    Bjorken, James D.; Essig, Rouven; Schuster, Philip; Toro, Natalia; /Stanford U., ITP

    2010-06-11

    Fixed-target experiments are ideally suited for discovering new MeV-GeV mass U(1) gauge bosons through their kinetic mixing with the photon. In this paper, we identify the production and decay properties of new light gauge bosons that dictate fixed-target search strategies. We summarize existing limits and suggest five new experimental approaches that we anticipate can cover most of the natural parameter space, using currently operating GeV-energy beams and well-established detection methods. Such experiments are particularly timely in light of recent terrestrial and astrophysical anomalies (PAMELA, FERMI, DAMA/LIBRA, etc.) consistent with dark matter charged under a new gauge force.

  6. EVALUATING MULTICOMPONENT COMPETITIVE ADSORPTION IN FIXED BEDS

    EPA Science Inventory

    An equilibrium column model (ECM) was developed to evaluate multicomponent competition in fixed-bed adsorption columns. The model ignores mass transfer resistances and uses ideal adsorbed solution theory to predict the competitive effects in multicomponent mixtures. The bed capac...

  7. Anderson Acceleration for Fixed-Point Iterations

    SciTech Connect

    Walker, Homer F.

    2015-08-31

    The purpose of this grant was to support research on acceleration methods for fixed-point iterations, with applications to computational frameworks and simulation problems that are of interest to DOE.

  8. Sequentially deployable maneuverable tetrahedral beam

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Crawford, R. F. (Inventor)

    1985-01-01

    A tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure is comprised of a number of repeating units of tandem tetralhedral sharing common sides. Fixed length battens are jointed into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons having a mid-point folding hinge. Joints, comprised of gussets pivotabley connected by links, permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The beam is suited to remote actuation. Longerons may be provided with powered mid-point hinges enabling beam erection and packaging under remote control. Providing one or more longerons with powered telescoping segments permits the shape of the beam central axis to be remotely manipulated so that the beam may function as a remote manipulator arm.

  9. Sequentially deployable maneuverable tetrahedral beam

    NASA Astrophysics Data System (ADS)

    Mikulas, M. M., Jr.; Crawford, R. F.

    1985-12-01

    A tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure is comprised of a number of repeating units of tandem tetralhedral sharing common sides. Fixed length battens are jointed into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons having a mid-point folding hinge. Joints, comprised of gussets pivotabley connected by links, permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The beam is suited to remote actuation. Longerons may be provided with powered mid-point hinges enabling beam erection and packaging under remote control. Providing one or more longerons with powered telescoping segments permits the shape of the beam central axis to be remotely manipulated so that the beam may function as a remote manipulator arm.

  10. Rolling Beam Umbilical System

    NASA Technical Reports Server (NTRS)

    Tatem, B. C., Jr.

    1983-01-01

    The decision to make the Centaur Vehicle a Space Transportation System (STS) payload meant that new ground support equipment provisions at Launch Pads Pads 39A and 39B were required. These new equipment provisions were needed to service the Centaur vehicle while it was installed in the Orbiter's payload bay prior to launch. This paper describes the design of a new rolling beam umbilical syste (RBUS) being added to the pad fixed service structure (FSS) in order to provide the primary functions of liquid hydrogen (LH2) fill, drain, and vent. The carrier plate itself is a Government-furnished equipment item and of necessity became a T-O disconnect. This permits quick offloading in the event of an abort prior to lift-off. In addition to the rolling beam structure, mechanisms, and fluid lines, it was necessary to design and build a carrier plate simulator to support early development testing of the mast at the Launch Equipment Test Facility at Kennedy Space Center. The RBUS is designed to be compatible with the rotating service structure (RSS) to the extent that the umbilical may be deployed with the RSS mated with the vehicle. It is also designed to clear the RSS as the RSS rotates back out of the way. Accessibility to the Orbiter aft compartment via the 50-1 door had to be maintained.

  11. Characterizations of fixed points of quantum operations

    SciTech Connect

    Li Yuan

    2011-05-15

    Let {phi}{sub A} be a general quantum operation. An operator B is said to be a fixed point of {phi}{sub A}, if {phi}{sub A}(B)=B. In this note, we shall show conditions under which B, a fixed point {phi}{sub A}, implies that B is compatible with the operation element of {phi}{sub A}. In particular, we offer an extension of the generalized Lueders theorem.

  12. Fixed-target physics at Fermilab

    SciTech Connect

    Bjorken, J.D.

    1985-03-01

    The Fermilab Energy Saver is now successfully commissioned and fixed-target experimentation at high energy (800 GeV) has begun. In addition, a number of new experiments designed to exploit the unique features of the Tevatron are yet to come on-line. In this talk, we will review recent accomplishments in the fixed-target program and describe experiments in progress and others yet to come.

  13. Precise Point Positioning with Partial Ambiguity Fixing.

    PubMed

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  14. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  15. A beam optics study of the biomedical beam line at a proton therapy facility

    NASA Astrophysics Data System (ADS)

    Yun, Chong Cheoul; Kim, Jong-Won

    2007-10-01

    A biomedical beam line has been designed for the experimental area of a proton therapy facility to deliver mm to sub-mm size beams in the energy range of 20-50 MeV using the TRANSPORT/TURTLE beam optics codes and a newly-written program. The proton therapy facility is equipped with a 230 MeV fixed-energy cyclotron and an energy selection system based on a degrader and slits, so that beam currents available for therapy decrease at lower energies in the therapeutic beam energy range of 70-230 MeV. The new beam line system is composed of an energy-degrader, two slits, and three quadrupole magnets. The minimum beam sizes achievable at the focal point are estimated for the two energies of 50 and 20 MeV. The focused FWHM beam size is approximately 0.3 mm with an expected beam current of 20 pA when the beam energy is reduced to 50 MeV from 100 MeV, and roughly 0.8 mm with a current of 10 pA for a 20 MeV beam.

  16. 48 CFR 16.204 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Fixed-price incentive... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.204 Fixed-price incentive contracts. A fixed-price incentive contract is a fixed-price contract that provides for adjusting profit...

  17. 48 CFR 16.204 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price incentive... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.204 Fixed-price incentive contracts. A fixed-price incentive contract is a fixed-price contract that provides for adjusting profit...

  18. 48 CFR 16.204 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Fixed-price incentive... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.204 Fixed-price incentive contracts. A fixed-price incentive contract is a fixed-price contract that provides for adjusting profit...

  19. MINI-BUNCHED AND MICRO-BUNCHED SLOW EXTRACTED BEAMS FROM THE AGS.

    SciTech Connect

    BROWN,K.A.AHRENS,L.BRENNAN,J.M.GLENN,J.W.SIVERTZ,M.KOSCIELNIAK,S.R.

    2004-07-05

    Brookhaven National Laboratory's (BNLs) Alternating Gradient Synchrotron (AGS) has a long history of providing slow extracted proton beams to fixed target experiments. This program of providing high quality high intensity beams continues with two new experiments currently being designed for operation at the AGS. Both experiments require slow extracted beam, but with an added requirement that those beams be bunched. Bunched beam slow extraction techniques have been developed for both experiments and initial tests have been performed. In this report we describe the beam requirements for the two experiments, and present results of detailed simulations and initial beam tests.

  20. A comparison of carbide fracture during fixed depth and fixed load scratch tests

    SciTech Connect

    Prasad, S.V.; Kosel, T.H.

    1985-01-01

    In order to simulate abrasion of dual-phase materials containing large carbides under fixed depth conditions an apparatus has been designed and used to perform scratch tests at a fixed depth of cut on such materials. The scratch test consists of two support arms tipped with small steel balls held in contact with surface by /sup 700/ g, while the scratch tool is mounted on the tip of a central arm whose adjustable length allow control of the depth of cut. The scratch tool does not deflect significant when it encounters a large carbide. Scratch tests with the new apparatus have been performed on Co-base Stellite alloys containing large Cr-rich carbides, using individual particles of alumina as scratch tools to generate fixed depth scratches. A in situ SEM scratch test apparatus has also been used to genrate fixed load scratches. Comparison of the scratches shows that for comparable average scratch depths, under fixed load conditions the scratch tool deflects over the carbides without causing fracture, but that since it cannot deflect under fixed depth conditions it induces gross carbide fracture. Results suggest that the fixed depth scratch test can be successfully employed to simulate fixed depth abrasion, which has been previously shown to generate gross carbide fracture in these alloys. The in situ SEM scratch test simulates fixed load abrasion conditions such as those which occur in rubber wheel abrasion tests. 12 refs., 9 figs

  1. Reduction of beam hardening artifacts in cone-beam CT imaging via SMART-RECON algorithm

    NASA Astrophysics Data System (ADS)

    Li, Yinsheng; Garrett, John; Chen, Guang-Hong

    2016-03-01

    When an automatic exposure control is introduced in C-arm cone beam CT data acquisition, the spectral inconsistencies between acquired projection data are exacerbated. As a result, conventional water/bone correction schemes are not as effective as in conventional diagnostic x-ray CT acquisitions with a fixed tube potential. In this paper, a new method was proposed to reconstruct several images with different degrees of spectral consistency and thus different levels of beam hardening artifacts. The new method relies neither on prior knowledge of the x-ray beam spectrum nor on prior compositional information of the imaging object. Numerical simulations were used to validate the algorithm.

  2. External Beam Therapy (EBT)

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z External Beam Therapy (EBT) External beam therapy (EBT) is a ... follow-up should I expect? What is external beam therapy and how is it used? External beam ...

  3. Inadvertent tooth movement with fixed lingual retainers.

    PubMed

    Shaughnessy, Timothy G; Proffit, William R; Samara, Said A

    2016-02-01

    Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed. PMID:26827985

  4. Compact Fixed-exit UHV DCM for XAFS

    SciTech Connect

    Rickers, K.; Brueggmann, U.; Drube, W.; Herrmann, M.; Heuer, J.; Welter, E.; Schulte-Schrepping, H.; Schulz-Ritter, H.

    2007-01-19

    A double-crystal, UHV-compatible monochromator for XAFS applications at bending magnet beamlines has been designed. It uses two crystal sets, Si(111) and (311), on a common central rotation axis driven by an ex-vacuo goniometer. All mechanical and electrical components are mounted on a 400 mm UHV flange which is attached to a compact vacuum chamber. The first crystals are water cooled using connector- and bellowless tubing through the fluidic sealed feedthrough of the central rotation. The first crystal set is mounted off-axis and can be translated vertically to keep the fixed exit condition. The second crystal set uses small crystals of the same size as the first. In order to accept the reflected beam of the first crystal at small Bragg angles, it is tangentially translated along the beam. The angle can be varied from 5 deg. to 55.5 deg. resulting in a total energy range 2.4 - 43.4 keV for Si(111)/(311). Crystal sets are interchangeable by translating the vacuum chamber. Angle encoding is achieved by a Renishaw incremental optical encoder in vacuo.

  5. Merged beam studies for astrobiology

    NASA Astrophysics Data System (ADS)

    De Ruette, Nathalie; Miller, Kenneth A.; O'Connor, Aodh; Stuetzel, Julia; Urbain, Xavier; Savin, Daniel Wolf

    2014-06-01

    The chain of chemical reactions leading towards life is thought to begin in molecular clouds when atomic carbon and oxygen are fixed into molecules. Reactions of neutral atomic C with H3+ is one of the first steps in the gas phase chemistry leading to the formation of complex organic molecules within such clouds. Water, believed to be vital for life, can form via a chain of gas-phase astrochemical reactions that begin with neutral atomic O reacting with H3+. Uncertainties in the thermal rate coefficient for these reactions hinder our ability to understand the first links in the chemical chain leading towards life. Theory and experiment have yet to converge in either the magnitude or temperature dependence. Theory provides little insight as fully quantum mechanical calculations for reactions involving four or more atoms are too complex for current capabilities. On the other hand, measurements of cross sections and rate coefficients for reactions of atoms with molecular ions are extremely challenging. This is due to the difficulty in producing sufficiently intense and well characterized beams of neutral atoms. We have developed a novel merged beam apparatus to study reactions of neutral atoms with molecular ions at the low collision energies relevant for molecular cloud studies. Photodetachment of atomic anion beams, with an 808-nm (1.53-eV) laser beam, is used to produce beams of neutral C and O, each in their ground term as occurs in molecular clouds. The neutral beam is then merged with a velocity matched, co-propagating H3+ beam, in order to study reactions of C and O on H3+. The merged beams method allows us to use fast beams (keV in the lab frame), which are easy to handle and monitor, while being able to achieve relative collision energies down to ≈10 meV. Using the measured merged beams rate coefficient, we are able to extract cross sections which we can then convolve with a Maxwellian energy spread to generate a thermal rate coefficient for molecular cloud

  6. Stability of a non-orthogonal stagnation flow to three dimensional disturbances

    NASA Technical Reports Server (NTRS)

    Lasseigne, D. G.; Jackson, T. L.

    1991-01-01

    A similarity solution for a low Mach number nonorthogonal flow impinging on a hot or cold plate is presented. For the constant density case, it is known that the stagnation point shifts in the direction of the incoming flow and that this shift increases as the angle of attack decreases. When the effects of density variations are included, a critical plate temperature exists; above this temperature the stagnation point shifts away from the incoming stream as the angle is decreased. This flow field is believed to have application to the reattachment zone of certain separated flows or to a lifting body at a high angle of attack. Finally, the stability of this nonorthogonal flow to self similar, 3-D disturbances is examined. Stability properties of the flow are given as a function of the parameters of this study; ratio of the plate temperature to that of the outer potential flow and angle of attack. In particular, it is shown that the angle of attack can be scaled out by a suitable definition of an equivalent wavenumber and temporal growth rate, and the stability problem for the nonorthogonal case is identical to the stability problem for the orthogonal case.

  7. Functional Implications of Ubiquitous Semicircular Canal Non-Orthogonality in Mammals

    PubMed Central

    Berlin, Jeri C.; Kirk, E. Christopher; Rowe, Timothy B.

    2013-01-01

    The ‘canonical model’ of semicircular canal orientation in mammals assumes that 1) the three ipsilateral canals of an inner ear exist in orthogonal planes (i.e., orthogonality), 2) corresponding left and right canal pairs have equivalent angles (i.e., angle symmetry), and 3) contralateral synergistic canals occupy parallel planes (i.e., coplanarity). However, descriptions of vestibular anatomy that quantify semicircular canal orientation in single species often diverge substantially from this model. Data for primates further suggest that semicircular canal orthogonality varies predictably with the angular head velocities encountered in locomotion. These observations raise the possibility that orthogonality, symmetry, and coplanarity are misleading descriptors of semicircular canal orientation in mammals, and that deviations from these norms could have significant functional consequences. Here we critically assess the canonical model of semicircular canal orientation using high-resolution X-ray computed tomography scans of 39 mammal species. We find that substantial deviations from orthogonality, angle symmetry, and coplanarity are the rule for the mammals in our comparative sample. Furthermore, the degree to which the semicircular canals of a given species deviate from orthogonality is negatively correlated with estimated vestibular sensitivity. We conclude that the available comparative morphometric data do not support the canonical model and that its overemphasis as a heuristic generalization obscures a large amount of functionally relevant variation in semicircular canal orientation between species. PMID:24260256

  8. Divergence preserving discrete surface integral methods for Maxwell's curl equations using non-orthogonal unstructured grids

    NASA Technical Reports Server (NTRS)

    Madsen, Niel K.

    1992-01-01

    Several new discrete surface integral (DSI) methods for solving Maxwell's equations in the time-domain are presented. These methods, which allow the use of general nonorthogonal mixed-polyhedral unstructured grids, are direct generalizations of the canonical staggered-grid finite difference method. These methods are conservative in that they locally preserve divergence or charge. Employing mixed polyhedral cells, (hexahedral, tetrahedral, etc.) these methods allow more accurate modeling of non-rectangular structures and objects because the traditional stair-stepped boundary approximations associated with the orthogonal grid based finite difference methods can be avoided. Numerical results demonstrating the accuracy of these new methods are presented.

  9. Review of the inverse scattering problem at fixed energy in quantum mechanics

    NASA Technical Reports Server (NTRS)

    Sabatier, P. C.

    1972-01-01

    Methods of solution of the inverse scattering problem at fixed energy in quantum mechanics are presented. Scattering experiments of a beam of particles at a nonrelativisitic energy by a target made up of particles are analyzed. The Schroedinger equation is used to develop the quantum mechanical description of the system and one of several functions depending on the relative distance of the particles. The inverse problem is the construction of the potentials from experimental measurements.

  10. Radiative convection with a fixed heat flux

    NASA Astrophysics Data System (ADS)

    Aumaı̂tre, S.

    2001-10-01

    We have determined the marginal stability curve of convective instability in the usual Rayleigh-Bénard configuration with radiative transfer and a fixed total heat flux at the boundaries instead of a fixed temperature. In the Milne-Eddington approximation, radiative transfer introduces a new length scale and breaks the invariance of the Boussinesq equations under an arbitrary temperature shift, which occurs when the heat flux is fixed at the boundaries. The convergence to the limits where the non-radiative cases are expected is studied in this approximation. Then, using a second-order perturbative calculation, we show that the presence of radiation can change qualitatively the instability pattern: there is a range of optical parameters where the Cahn-Hillard equation is not anymore the one appropriate to describe the instability near the threshold.

  11. [Fixed-drug combinations for hypertension].

    PubMed

    Sato, Nobuyuki; Hasebe, Naoyuki

    2014-08-01

    The recent guidelines for the treatment of hypertension recommend a fixed-dose combination (polypill) therapy to achieve optimal blood pressure (BP) control. Among them, angiotensin receptor blockers (ARBs) with calcium channel blockers (CCBs) or diuretics are the representative recommended combination since each drug has evidence of reducing cardiovascular events. Recent studies using ambulatory blood pressure monitoring have also suggested that the fixed-dose ARB-based combination therapies with either CCBs or diuretics are well tolerated and effectively lower the BP throughout a 24-hour interval by their long-acting half-lives, nighttime BP lowering effect and improving adherence. It will become more important to use these fixed-dose antihypertensive drugs adequately for controlling the 24-hour blood pressure. PMID:25167756

  12. CEBAF beam loss accounting

    SciTech Connect

    Ursic, R.; Mahoney, K.; Hovater, C.; Hutton, A.; Sinclair, C.

    1995-12-31

    This paper describes the design and implementation of a beam loss accounting system for the CEBAF electron accelerator. This system samples the beam curent throughout the beam path and measures the beam current accurately. Personnel Safety and Machine Protection systems use this system to turn off the beam when hazardous beam losses occur.

  13. Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

    SciTech Connect

    Powell, J.R.; Botts, T.E.; Hertzberg, A.

    1981-01-01

    Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

  14. Carbon-Fixing Reactions of Photosynthesis.

    PubMed

    2016-07-01

    Summaryplantcell;28/7/tpc.116.tt0716/FIG1F1fig1Photosynthesis in plants converts the energy of sunlight into chemical energy. Although photosynthesis involves many proteins and catalytic processes, it often is described as two sets of reactions, the light-dependent reactions and the carbon-fixing reactions. This lesson introduces the core biochemistry of the carbon-fixing reactions of photosynthesis, as well as its variations, C4 and CAM. Finally, it addresses how and why plants are affected by rising atmospheric CO2 levels, and research efforts to increase photosynthetic efficiency in current and future conditions. PMID:27493209

  15. Laser beam centering and pointing system

    DOEpatents

    Rushford, Michael Charles

    2015-01-13

    An optical instrument aligns an optical beam without the need for physical intervention of the instrument within the apparatus or platforms from which the trajectory of the beam to be ascertained. The alignment apparatus and method enable the desired function to be realized without the placement of physical apertures or sensors directly in the path of the beam through the system whose spatial position and slope is to be sought. An image plane provides the observer with a pair of well-defined images that are indicative of the beam centering and pointing alignment parameters. The optical alignment can be realized without the need for referencing to an external or fixed set of coordinates or fiducials. The instrument can therefore service situations where adverse environments would otherwise prohibit the use of such instruments, including regions of high radiation, high temperature, vacuum and/or cryogenic atmospheres.

  16. SPS Beam Steering for LHC Extraction

    SciTech Connect

    Gianfelice-Wendt, Eliana; Bartosik, Hannes; Cornelis, Karel; Norderhaug Drøsdal, Lene; Goddard, Brennan; Kain, Verena; Meddahi, Malika; Papaphilippou, Yannis; Wenninger, Jorg

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  17. Beam profile effects on NPB performance

    SciTech Connect

    Leclaire, R.J. Jr.; Bunker, W.J.

    1988-03-01

    A comparison of neutral particle beam (NPB) brightness for various neutral beam profiles indicates that the widely used assumption of a Gaussian profile may be misleading for collisional neutralizers. An analysis of available experimental evidence shows that lower peaks and higher tails, compared to a Gaussian beam profile, are observed out of collisional neutralizers, which implies that peak brightness is over estimated, and for a given NPB platform-to-target range, the beam current (power), dwell time or some combination of such engagement parameters would have to be altered to maintain a fixed dose on the target. Based on the present analysis, this factor is nominally about 2.4 but may actually be as low as 1.8 or as high as 8. This is an important consideration in estimating NPB constellation performance in SDI engagement contexts.

  18. Beam quality measure for vector beams.

    PubMed

    Ndagano, Bienvenu; Sroor, Hend; McLaren, Melanie; Rosales-Guzmán, Carmelo; Forbes, Andrew

    2016-08-01

    Vector beams have found a myriad of applications, from laser materials processing to microscopy, and are now easily produced in the laboratory. They are usually differentiated from scalar beams by qualitative measures, for example, visual inspection of beam profiles after a rotating polarizer. Here we introduce a quantitative beam quality measure for vector beams and demonstrate it on cylindrical vector vortex beams. We show how a single measure can be defined for the vector quality, from 0 (purely scalar) to 1 (purely vector). Our measure is derived from a quantum toolkit, which we show applies to classical vector beams. PMID:27472580

  19. Simple electron beam guiding system including automatic capture circuitry

    NASA Astrophysics Data System (ADS)

    Stein, W.; Schulenburg, M.; Freund, F.

    1980-08-01

    The spatial stability of the point of impact of an electron beam is a stringent requirement in some experiments such as soft x-ray spectroscopy using a focussing curved crystal spectrometer. The occasinally poor design of moderately priced electron guns, thermal instabilities, electromagnetic stray fields and so on, make spot stabilization an arduous task. The problem can be solved to some extent by a simple electron beam guiding system: a small fraction of the electron beam is captured by a metal wire mounted in the vicinity of the target. The beam position is fixed, if this fraction is controlled by a feedback loop via the deflection plates of the gun.

  20. Energy compensation of slow extracted beams with RF acceleration

    NASA Astrophysics Data System (ADS)

    Fujimoto, Tetsuya; Souda, Hikaru; Torikoshi, Masami; Kanai, Tatsuaki; Yamada, Satoru; Noda, Koji

    2016-03-01

    In a conventional carbon-ion radiotherapy facility, a carbon-ion beam is typically accelerated up to an optimum energy, slowly extracted from a synchrotron ring by a resonant slow extraction method, and ultimately delivered to a patient through a beam-delivery system. At Japan's Gunma University, a method employing slow-beam extraction along with beam-acceleration has been adopted. This method slightly alters the extracted-beam's energy owing to the acceleration component of the process, which subsequently results in a residual-range variation of approximately 2 mm in water-equivalent length. However, this range variation does not disturb a distal dose distribution with broad-beam methods such as the single beam-wobbling method. With the pencil-beam 3D scanning method, however, such a range variation disturbs a distal dose distribution because the variation is comparable to slice thickness. Therefore, for pencil-beam 3D scanning, an energy compensation method for a slow extracted beam is proposed in this paper. This method can compensate for the aforementioned energy variances by controlling net energy losses through a rotatable energy absorber set fixed between the synchrotron exit channel and the isocenter. Experimental results demonstrate that beam energies can be maintained constant, as originally hypothesized. Moreover, energy-absorber positions were found to be significantly enhanced by optimizing beam optics for reducing beam-size growth by implementation of the multiple-scattering effect option.

  1. Timing shifts due to NIF beam repointing

    SciTech Connect

    Koch, J

    2007-08-15

    Repointing a NIF beam to hit a target position off target chamber center (TCC) will introduce a timing shift due to changes in the light pathlength. This shift could be important for target experiment requirements even for targets placed at TCC, since beam timing test shots will place beams up to 15 mm off TCC in order to spatially separate them on foil targets. In particular, timing errors due to beam repointing need to be considered against the 30 ps RMS timing requirement. Since the repointing process will keep the beam passing through a fixed point in the final optics assembly (the conversion crystal) by tip/tilt adjustments of two turning mirrors (LM5 and LM7), the problem naturally divides into two parts: Timing offsets past the conversion crystal due to target positioning changes, and timing offsets behind the fixed point on the conversion crystal due to turning mirror adjustments. Timing offsets past the conversion crystal can be significant, but are trivial to calculate exactly; however, an exact calculation of timing offsets behind the fixed point on the conversion crystal would require a three-dimensional optomechanical raytrace model to be developed for every beamline, and this would be difficult and expensive. In this memo, I estimate the magnitude of timing offsets due to pathlength changes behind the conversion crystal by analysis of a worst-case model. I conclude that these timing offsets are insignificant compared with the current allocation in the 30 ps RMS timing requirement, and that more detailed raytrace modeling of individual beams is not necessary.

  2. Management strategy 3: fixed rate fertilizer applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous chapters outlined management strategies for pond fertilization that take into account specific individual pond nutrient needs. Those methods would most likely be more ecologically efficient than a pre-determined fixed-rate nutrient addition strategy. However, the vast majority of available ...

  3. Fixed Drug Eruption Due to Ornidazole

    PubMed Central

    Gupta, Ramji

    2014-01-01

    A 56-year-old male developed an ulcer on his glans penis and mucosae of upper and lower lips 3 days after taking ofloxacin, cephalexin, and ornidazole. Clinically, a provisional diagnosis of fixed drug eruption was made. The causative drug was confirmed by an oral provocation test which triggered a reactivation of all lesions only with ornidazole. PMID:25484435

  4. Fixing the Shadows While Moving the Gnomon

    ERIC Educational Resources Information Center

    Gangui, Alejandro

    2015-01-01

    It is a common practice to fix a vertical gnomon and study the moving shadow cast by it. This shows our local solar time and gives us a hint regarding the season in which we perform the observation. The moving shadow can also tell us our latitude with high precision. In this paper we propose to exchange the roles and while keeping the shadows…

  5. Why to Treat Subjects as Fixed Effects

    ERIC Educational Resources Information Center

    Adelman, James S.; Estes, Zachary

    2015-01-01

    Adelman, Marquis, Sabatos-DeVito, and Estes (2013) collected word naming latencies from 4 participants who read 2,820 words 50 times each. Their recommendation and practice was that R2 targets set for models should take into account subject idiosyncrasies as replicable patterns, equivalent to a subjects-as-fixed-effects assumption. In light of an…

  6. Long-term fixed income market structure

    NASA Astrophysics Data System (ADS)

    Grilli, Luca

    2004-02-01

    Long-term fixed income market securities present a strong positive correlation in daily returns. By using a metrical approach and considering “modified” time series, I show how it is possible to show a more complex structure which depends strictly on the maturity date.

  7. Physics landscape-fixed target energies

    SciTech Connect

    Berger, E.L.

    1989-10-01

    An introductory review is presented of physics issues and opportunities at Fermilab fixed-target energies. Included are discussions of precision electroweak studies; deep inelastic lepton scattering; heavy quark production, spectroscopy, and decays; perturbative QCD; prompt photon production; massive lepton production; and spin dependence. 79 refs., 7 figs.

  8. Fixed drug eruption against rupatadine fumarate.

    PubMed

    Fidan, Vural; Fidan, Tulin

    2011-09-01

    Second generation of antihistaminics have better therapeutic efficacy and more predictable pharmacological responses at lower doses than older compounds. However, new compounds have a reduced adverse reaction profile; clinicians can also encounter some unexpected adverse effects of these newer compounds. We report the first case of fixed drug eruption of rupatadine fumarate, which was confirmed by oral provocation test. PMID:21959412

  9. 29 CFR 1910.27 - Fixed ladders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... details shall be such as to prevent or minimize the accumulation of water on wood parts. (iii) When... and fastenings. (2) Design stresses. Design stresses for wood components of ladders shall not exceed those specified in § 1910.25. All wood parts of fixed ladders shall meet the requirements of §...

  10. 29 CFR 1910.27 - Fixed ladders.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... details shall be such as to prevent or minimize the accumulation of water on wood parts. (iii) When... and fastenings. (2) Design stresses. Design stresses for wood components of ladders shall not exceed those specified in § 1910.25. All wood parts of fixed ladders shall meet the requirements of §...

  11. 29 CFR 1910.27 - Fixed ladders.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... details shall be such as to prevent or minimize the accumulation of water on wood parts. (iii) When... and fastenings. (2) Design stresses. Design stresses for wood components of ladders shall not exceed those specified in § 1910.25. All wood parts of fixed ladders shall meet the requirements of §...

  12. 29 CFR 1910.27 - Fixed ladders.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... details shall be such as to prevent or minimize the accumulation of water on wood parts. (iii) When... and fastenings. (2) Design stresses. Design stresses for wood components of ladders shall not exceed those specified in § 1910.25. All wood parts of fixed ladders shall meet the requirements of §...

  13. Deep Learning Experiences within a Fixed Schedule

    ERIC Educational Resources Information Center

    Green, Julie; Olmstead, Laurie

    2011-01-01

    Two and a half years ago, elementary school librarians in the Birmingham Public School district (Troy, Michigan) had to change to a fixed schedule for half the day with kindergarten through second grade students. This change was due to cutbacks and the need for common planning time among classroom teachers. School librarians found themselves…

  14. ASIC For Complex Fixed-Point Arithmetic

    NASA Technical Reports Server (NTRS)

    Petilli, Stephen G.; Grimm, Michael J.; Olson, Erlend M.

    1995-01-01

    Application-specific integrated circuit (ASIC) performs 24-bit, fixed-point arithmetic operations on arrays of complex-valued input data. High-performance, wide-band arithmetic logic unit (ALU) designed for use in computing fast Fourier transforms (FFTs) and for performing ditigal filtering functions. Other applications include general computations involved in analysis of spectra and digital signal processing.

  15. Stress tolerant crops from nitrogen fixing trees

    SciTech Connect

    Becker, R.; Saunders, R.M.

    1983-01-01

    Notes are given on the nutritional quality and uses of: pods of Geoffroea decorticans, a species tolerant of saline and limed soils and saline water; seeds of Olneya tesota which nodulates readily and fixes nitrogen and photosynthesizes at low water potential; and pods of Prosopis chilensis and P. tamarugo which tolerate long periods without rain. 3 references.

  16. Fixing Advising: A Model for Faculty Advising

    ERIC Educational Resources Information Center

    Crocker, Robert M.; Kahla, Marlene; Allen, Charlotte

    2014-01-01

    This paper addresses mandates to fix the advising process with a focus on faculty advising systems. Measures of student success and satisfaction, administrative issues, and faculty concerns are among the many factors discussed. Regression analysis is used to explore long-voiced faculty complaints that students do not follow advice. A case study is…

  17. Fixed Versus Flexible MMPI Diagnostic Rules.

    ERIC Educational Resources Information Center

    Hsu, Louis M.

    1988-01-01

    Demonstrates the consequences on total misdiagnosis rates of using conventional (fixed) rather than flexible (Bayesian) rules when using the Minnesota Multiphasic Personality Inventory in diagnosis. Concludes that the range of base rates and the separation of distributions of normal and abnormal scores affect the difference in the misdiagnosis…

  18. Beam-Bem interactions

    SciTech Connect

    Kim, Hyung Jin; /Fermilab

    2011-12-01

    In high energy storage-ring colliders, the nonlinear effect arising from beam-beam interactions is a major source that leads to the emittance growth, the reduction of beam life time, and limits the collider luminosity. In this paper, two models of beam-beam interactions are introduced, which are weak-strong and strong-strong beam-beam interactions. In addition, space-charge model is introduced.

  19. 46 CFR 28.260 - Electronic position fixing devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Electronic position fixing devices. 28.260 Section 28... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for...

  20. 46 CFR 28.260 - Electronic position fixing devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Electronic position fixing devices. 28.260 Section 28... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for...

  1. 46 CFR 28.260 - Electronic position fixing devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Electronic position fixing devices. 28.260 Section 28... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for...

  2. 46 CFR 28.260 - Electronic position fixing devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Electronic position fixing devices. 28.260 Section 28... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for...

  3. 46 CFR 28.260 - Electronic position fixing devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Electronic position fixing devices. 28.260 Section 28... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for...

  4. 48 CFR 16.403 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price incentive... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Incentive Contracts 16.403 Fixed-price incentive contracts. (a) Description. A fixed-price incentive contract is a fixed-price contract that provides...

  5. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause)...

  6. 48 CFR 16.403 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Fixed-price incentive... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Incentive Contracts 16.403 Fixed-price incentive contracts. (a) Description. A fixed-price incentive contract is a fixed-price contract that provides...

  7. 48 CFR 52.216-9 - Fixed Fee-Construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Fixed Fee-Construction. 52....216-9 Fixed Fee—Construction. As prescribed in 16.307(c), insert the following clause in solicitations and contracts when a cost-plus-fixed-fee construction contract is contemplated: Fixed...

  8. Simple beam profile monitor

    SciTech Connect

    Gelbart, W.; Johnson, R. R.; Abeysekera, B.

    2012-12-19

    An inexpensive beam profile monitor is based on the well proven rotating wire method. The monitor can display beam position and shape in real time for particle beams of most energies and beam currents up to 200{mu}A. Beam shape, position cross-section and other parameters are displayed on a computer screen.

  9. Beam-beam effects in the Tevatron

    SciTech Connect

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  10. 24 CFR 84.80 - Conditions for use of Lump Sum (fixed price or fixed amount) grants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (fixed price or fixed amount) grants. 84.80 Section 84.80 Housing and Urban Development Office of the... AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Use of Lump Sum Grants § 84.80 Conditions for use of Lump Sum (fixed price or fixed amount) grants. (a) Heads...

  11. Straw man 900-1000 GeV crystal extraction test beam for Fermilab collider operation

    SciTech Connect

    Carrigan, R.A. Jr.

    1996-10-01

    A design for a 900-1000 GeV, 100 khz parasitic test beam for use during collider operations has been developed. The beam makes use of two bent crystals, one for extraction and the other one for redirecting the beam in to the present Switchyard beam system. The beam requires only a few modifications in the A0 area and largely uses existing devices. It should be straight-forward to modify one or two beam lines in the fixed target experimental areas to work above 800 GeV. Possibilities for improvements to the design,to operate at higher fluxes are discussed.

  12. Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

    NASA Astrophysics Data System (ADS)

    An, Dong Hyun; Hahn, Garam; Park, Chawon

    2015-02-01

    In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

  13. Fixed-Cell Imaging of Schizosaccharomyces pombe.

    PubMed

    Hagan, Iain M; Bagley, Steven

    2016-01-01

    The acknowledged genetic malleability of fission yeast has been matched by impressive cytology to drive major advances in our understanding of basic molecular cell biological processes. In many of the more recent studies, traditional approaches of fixation followed by processing to accommodate classical staining procedures have been superseded by live-cell imaging approaches that monitor the distribution of fusion proteins between a molecule of interest and a fluorescent protein. Although such live-cell imaging is uniquely informative for many questions, fixed-cell imaging remains the better option for others and is an important-sometimes critical-complement to the analysis of fluorescent fusion proteins by live-cell imaging. Here, we discuss the merits of fixed- and live-cell imaging as well as specific issues for fluorescence microscopy imaging of fission yeast. PMID:27371603

  14. Fixed drug eruptions with intraoral presentation

    PubMed Central

    Srivastava, Rahul; Bihari, Manorama; Bhuvan, Jyoti; Saad, Ahmed

    2015-01-01

    Fixed-drug eruption (FDE) is an unusual and rare adverse drug reaction. This type of reaction is actually a delayed type of hypersensitivity reaction that occurs as lesions recurring at the same skin site due to repeated intake of an offending drug. Here is a case report of a 58-year-old male patient who developed intraoral FDEs after ingestion of the first dose of ornidazole. PMID:26097341

  15. Azithromycin induced bullous fixed drug eruption

    PubMed Central

    Das, Anupam; Sancheti, Karan; Podder, Indrashis; Das, Nilay Kanti

    2016-01-01

    Fixed drug eruption (FDE) is a common type of drug eruption seen in skin clinics. It is characterized by solitary or multiple, round to oval erythematous patches with dusky red centers, some of which may progress to bulla formation. Bullous FDE may be caused by a number of drugs. We hereby describe a case of azithromycin-induced bullous FDE; to the best of our knowledge, this is the first such case being reported. PMID:26997729

  16. Topology of the Two Fixed Centers Problem

    NASA Astrophysics Data System (ADS)

    Cordero, A.; Martínez Alfaro, J.; Vindel, P.

    2002-02-01

    In this paper we give a complete topological characterization of the Two Fixed Centers (TFC) problem flow. This characterization is based on the link formed by some basic periodic orbits. The Restricted Circular Three-Body (RCTB) problem is considered as a perturbation of the TFC in the case of two primaries with equal masses. The basic periodic orbits of the integrable problem can be continued in the non-integrable one.

  17. RSRM nozzle fixed housing cooldown test

    NASA Technical Reports Server (NTRS)

    Bolieau, D. J.

    1989-01-01

    Flight 5 aft segments with nozzles were exposed to -17 F temperatures while awaiting shipment to KSC in February, 1989. No records were found which show that any previous nozzles were exposed to air temperatures as low as those seen by the Flight 5 nozzles. Thermal analysis shows that the temperature of the fixed housing, and forward and aft exit cone components dropped as low as -10 F. Structural analysis of the nozzles at these low temperatures show the forward and aft exit cone adhesive bonds to have a positive margin of safety, based on a 2.0 safety factor. These analyses show the normal and shear stresses in the fixed housing bond as low values. However, the hoop and meridinal stresses were predicted to be in the 4000 psi range; the failure stress allowable of EA913NA adhesive at -7 F. If the bonds did break in directions perpendicular to the surfaces, called bond crazing, no normal bond strength would be lost. Testing was conducted in two phases, showing that no degradation to the adhesive bonds occurred while the Flight 5 nozzles were subjected to subzero temperatures. The results of these tests are documented. Phase 1 testing cooled a full-scale RSRM insulated fixed housing to -13 F, with extensive bondline inspections. Phase 2 testing cooled the witness panel adhesive tensile buttions to -13 F, with failure strengths recorded before, during, and after the cooldown.

  18. Fixed-combination and emerging glaucoma therapies.

    PubMed

    Woodward, David F; Chen, June

    2007-05-01

    Ocular hypotensive agents are the only approved pharmacotherapy for glaucoma. Despite significant advances during the past two decades, a large proportion of glaucoma patients require more than one drug. The most recent additions to the armamentarium of antiglaucoma drugs are fixed-combination products for the glaucoma patient who is insufficiently responsive to monotherapy. Fixed-combination products have the combined efficacy of two ocular hypotensive drugs, and the convenience of a two-drug treatment regimen in a single container, which may aid patient adherence to treatment. Available fixed-combination products consist of timolol 0.5% as an invariant with brimonidine 0.2%, dorzolamide 2%, travoprost 0.004%, latanoprost 0.005% or bimatoprost 0.03%. Research on more advanced antiglaucoma medications continues. Promising new directions appear to be the Rho-kinase inhibitors, microtubule-disrupting agents, serotonergics and cannabimimetics. Efforts continue to improve existing antiglaucoma drugs in an attempt to design second-generation cholinomimetics, adrenergics, prostaglandins and prostamides. PMID:17604504

  19. Zirconia in fixed prosthesis. A literature review

    PubMed Central

    Román-Rodríguez, Juan L.; Ferreiroa, Alberto; Solá-Ruíz, María F.; Fons-Font, Antonio

    2014-01-01

    Statement of problem: Evidence is limited on the efficacy of zirconia-based fixed dental prostheses. Objective: To carry out a literature review of the behavior of zirconium oxide dental restorations. Material and Methods: This literature review searched the Pubmed, Scopus, Medline and Cochrane Library databases using key search words “zirconium oxide,” “zirconia,” “non-metal restorations,” “ceramic oxides,” “veneering ceramic,” “zirconia-based fixed dental prostheses”. Both in vivo and in vitro studies into zirconia-based prosthodontic restoration behavior were included. Results: Clinical studies have revealed a high rate of fracture for porcelain-veneered zirconia-based restorations that varies between 6% and 15% over a 3- to 5-year period, while for ceramo-metallic restorations the fracture rate ranges between 4 and 10% over ten years. These results provoke uncertainty as to the long-term prognosis for this material in the oral medium. The cause of veneering porcelain fractures is unknown but hypothetically they could be associated with bond failure between the veneer material and the zirconia sub-structure. Key words:Veneering ceramic, zirconia-based ceramic restoration, crown, zirconia, tooth-supported fixed prosthesis. PMID:24596638

  20. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P. )

    1993-12-25

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. We describe what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. We present initial results from a study of beam entropy for an intense space-charge dominated beam.

  1. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P.

    1993-06-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam.

  2. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam.

  3. Relativistic electron beam generator

    DOEpatents

    Mooney, L.J.; Hyatt, H.M.

    1975-11-11

    A relativistic electron beam generator for laser media excitation is described. The device employs a diode type relativistic electron beam source having a cathode shape which provides a rectangular output beam with uniform current density.

  4. Beam imaging sensor

    DOEpatents

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  5. Beam imaging sensor

    SciTech Connect

    McAninch, Michael D; Root, Jeffrey J

    2015-03-31

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  6. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  7. In celebration of the fixed target program with the Tevatron

    SciTech Connect

    Jeffrey A. Appel et al.

    2001-12-28

    The Tevatron is the world's first large superconducting accelerator. With its construction, we gained the dual opportunities to advance the state of the art in accelerator technology with the machine itself and in particle physics with the experiments that became possible in a higher energy regime. There have been 43 experiments in the Tevatron fixed target program. Many of these are better described as experimental programs, each with a broad range of physics goals and results, and more than 100 collaborating physicists and engineers. The results of this program are three-fold: (1) new technologies in accelerators, beams and detectors which advanced the state of the art; (2) new experimental results published in the refereed physics journals; and (3) newly trained scientists who are both the next generation of particle physicists and an important part of the scientific, technical and educational backbone of the country as a whole. In this book they compile these results. There are sections from each experiment including what their physics goals and results were, what papers were published, and which students have received degrees. Summaries of these results from the program as a whole are quite interesting, but the physics results from this program are too broad to summarize globally. The most important of the results appear in later sections of this booklet.

  8. Fractal materials, beams, and fracture mechanics

    NASA Astrophysics Data System (ADS)

    Ostoja-Starzewski, Martin; Li, Jun

    2009-11-01

    Continuing in the vein of a recently developed generalization of continuum thermomechanics, in this paper we extend fracture mechanics and beam mechanics to materials described by fractional integrals involving D, d and R. By introducing a product measure instead of a Riesz measure, so as to ensure that the mechanical approach to continuum mechanics is consistent with the energetic approach, specific forms of continuum-type equations are derived. On this basis we study the energy aspects of fracture and, as an example, a Timoshenko beam made of a fractal material; the local form of elastodynamic equations of that beam is derived. In particular, we review the crack driving force G stemming from the Griffith fracture criterion in fractal media, considering either dead-load or fixed-grip conditions and the effects of ensemble averaging over random fractal materials.

  9. Impaired Inhibitory Force Feedback in Fixed Dystonia.

    PubMed

    Mugge, Winfred; Schouten, Alfred C; van Hilten, Jacobus J; van der Helm, Frans C T

    2016-04-01

    Complex regional pain syndrome (CRPS) is a multifactorial disorder associated with an aberrant host response to tissue injury. About 25% of CRPS patients suffer poorly understood involuntary sustained muscle contractions associated with dysfunctional reflexes that result in abnormal postures (fixed dystonia). A recent modeling study simulated fixed dystonia (FD) caused by aberrant force feedback. The current study aims to validate this hypothesis by experimentally recording the modulation of reflexive force feedback in patients with FD. CRPS patients with and without FD, patients with FD but without CRPS, as well as healthy controls participated in the experiment. Three task instructions and three perturbation characteristics were used to evoke a wide range of responses to force perturbations. During position tasks ("maintain posture"), healthy subjects as well as patients resisted the perturbations, becoming more stiff than when being relaxed (i.e., the relax task). Healthy subjects and CRPS patients without FD were both more compliant during force tasks ("maintain force") than during relax tasks, meaning they actively gave way to the imposed forces. Remarkably, the patients with FD failed to do so. A neuromuscular model was fitted to the experimental data to separate the distinct contributions of position, velocity and force feedback, as well as co-contraction to the motor behavior. The neuromuscular modeling indicated that inhibitory force feedback is deregulated in patients with FD, for both CRPS and non-CRPS patients. From previously published simulation results and the present experimental study, it is concluded that aberrant force feedback plays a role in fixed dystonia. PMID:25955788

  10. Beam halo in mismatched proton beams.

    SciTech Connect

    Wangler, Thomas P.,; Allen, C. K.; Chan, D.; Colestock, P. L. ,; Crandall, K. R.; Qiang, J.; Garnett, R. W.; Lysenko, W. P.; Gilpatrick, J. D.; Schneider, J. D.; Schulze, M. E.; Sheffield, R. L.; Smith, H. V.

    2002-01-01

    Progress was made during the past decade towards a better understanding of halo formation caused by beam mismatch in high-intensity beams. To test these ideas an experiment was carried out at Los Alamos with proton beams in a 52-quadrupole focusing channel. Rms emittances and beam widths were obtained from measured beam profiles for comparison with the maximum emittance growth predictions of a free-energy model and the maximum haloamplitude predictions of a particle-core model. The experimental results are also compared with multiparticle simulations. In this paper we will present the experimental results and discuss the implications with respect to the validity of both the models and the simulations. Keywords: beam halo, emittance growth, beam profiles, simulations, space charge, mismatch

  11. Temporal correlations imaging fixed targets through turbulence.

    PubMed

    Gulich, Damián

    2016-06-15

    We study the temporal correlations from dynamic imaging through turbulence using incoherent light from fixed high-contrast targets. We conduct our experiment in controlled laboratory conditions using several values of the Cn2 constant from the weak to strong fluctuation regime. We employ detrended fluctuation analysis to measure long-range correlations while considering scintillation information for every recorded pixel. We find that turbulence strength generally increases temporal correlations in time series from pixels in high-contrast regions of the image. PMID:27304306

  12. Fixed Target Beauty Physics Experimental Programs

    SciTech Connect

    Garbincius, P.H.

    1987-11-01

    The current and near term future fixed target physics efforts in observing particles with open beauty are reviewed. This includes a compilation of the non-observation upper limits and the observation of both upsilon and b-states. A short discussion of the theoretical predictions for the hadro-produced beauty pairs is included. The major part of this review is devoted to the techniques and tricks employed, a survey of the current and proposed experiments. A personal summary of the experimental prospects concludes this report. 28 refs., 26 figs.

  13. Beam-beam interactions for bunched and unbunched beams

    SciTech Connect

    Courant, E D

    1980-01-01

    The beam-beam interaction is analyzed in terms of Chirikov's stochasticity model. Stochastic blow-up occurs when the density of resonance regions in phase space becomes large, and Arnold diffusion is assumed to depend on the density parameter below the stochastic threshold. The relation between the density parameter and the tune shift epsilon is affected by bunching of the beam and also by variations in the strengths of several interaction regions and by beam misalignment. It is seen that bunching can reduce the tolerable epsilon by as much as an order of magnitude in proton storage rings.

  14. Report of the super fixed target beauty facility working group on progress towards the SFT at the SSC

    SciTech Connect

    Brown, H.; Cumalat, J.; Carrigan, R.A.

    1992-12-31

    A low intensity 20 TeV proton beam extracted from the SSC by crystal channeling has been proposed for use in producing B hadrons in a fixed target configuration. This option for doing B physics offers a relatively inexpensive way of obtaining large numbers of reconstructable B decays for the study of rare B decays and CP violation in the B system. This paper reports on the progress during and since the 1990 Snowmass meeting in developing the techniques for the crystal extraction and discusses special advantages that an SSC fixed target spectrometer may have relative to other experimental methods for studying B decays.

  15. 47 CFR 22.1031 - Temporary fixed stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MOBILE SERVICES Offshore Radiotelephone Service § 22.1031 Temporary fixed stations. The FCC may, upon proper application therefor, authorize the construction and operation of temporary fixed stations in...

  16. 47 CFR 22.1031 - Temporary fixed stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MOBILE SERVICES Offshore Radiotelephone Service § 22.1031 Temporary fixed stations. The FCC may, upon proper application therefor, authorize the construction and operation of temporary fixed stations in...

  17. 48 CFR 31.102 - Fixed-price contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTRACTING REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Applicability 31.102 Fixed-price contracts... fixed-price contract clause requires the determination or negotiation of costs. However, application...

  18. Telecommunication using muon beams

    DOEpatents

    Arnold, Richard C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location.

  19. Fixed film phosphorus removal--flexible enough?

    PubMed

    Rogalla, F; Johnson, T L; McQuarrie, J

    2006-01-01

    While biological phosphorus removal (BPR) has been practised for 30 years, up to recently it has been restricted mainly to activated sludge processes, with the corresponding need for large basin volumes. Yet, research with biofilm reactors showed that the principle of alternate anaerobic and aerated conditions was applicable to fixed bacteria by changing the conditions in time rather than in space. Attached growth enhanced biological phosphorus removal (EBPR) systems are attractive because of their compactness and capability to retain high biomass levels. However, the phosphorus extraction depends on backwashes to enhance the phosphorus-rich attached biomass, and correct control of unsteady effluent quality created by frequently modified process conditions. Accordingly, EBPR remains a challenging task in terms of combining nitrogen and phosphorus removal using attached growth systems. Nevertheless, a combination of activated sludge and biofilm carriers, in the integrated fixed-film activated sludge system, provides treatment opportunities not readily available using suspended growth systems. Current practice is only at the beginning of exploiting the full potential of this combination, but the first full-scale results show that compact tankage and low nutrient results based on biological principles are possible. PMID:16889243

  20. Fixed Drug Eruption due to Achiote Dye

    PubMed Central

    Tattersall, Ian; Reddy, Bobby Y.

    2016-01-01

    Fixed drug eruption (FDE) is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing. PMID:26933409

  1. Fixed Drug Eruption due to Achiote Dye.

    PubMed

    Tattersall, Ian; Reddy, Bobby Y

    2016-01-01

    Fixed drug eruption (FDE) is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing. PMID:26933409

  2. Regulatory requirements for marketing fixed dose combinations

    PubMed Central

    Jayasheel, B. G.

    2010-01-01

    The development of fixed-dose combinations (FDCs) is becoming increasingly important from a public health perspective. FDCs have advantages when there is an identifiable patient population for whom treatment with a particular combination of actives in a fixed ratio is safe and effective and when all of the actives contribute to the overall therapeutic effect. Such combinations of drugs are particularly useful in the management of chronic diseases. In addition, there can be real clinical benefits in the form of increased efficacy and/or a reduced incidence of adverse effects. Additional advantages of FDCs are potentially lower costs of manufacturing compared to the costs of producing separate products administered concurrently, simpler logistics of distribution and reduced development of resistance in the case of antimicrobials. Above all, FDC therapy reduces pill burden and improves medication compliance. Although, FDCs seem to be ideal under certain pre-defined circumstances, if a dosing adjustment is warranted, there may not be an FDC available in the most appropriate strength for the patient and if an adverse drug reaction occurs from using an FDC, it may be difficult to identify the active ingredient responsible for causing the reaction. Appendix VI of Schedule Y (Drugs & Cosmetics Rules 1945, India) states the requirements for marketing approval of various types of FDCs. The same is further elaborated in this article to provide a detailed guidance including the clinical trial requirements. However, the heterogeneity of the therapeutic field makes it difficult to develop a standard guidance document. PMID:21350725

  3. Fixed-dose combination therapy for psoriasis.

    PubMed

    Guenther, Lyn C

    2004-01-01

    Fixed-dose combination therapy offers stable products containing two or more medications with different mechanisms of action and safety profiles. It is also convenient for patients since only one product rather than two or more needs to be applied. Topical corticosteroids are often the mainstay of therapy in psoriasis. Diprosalic and Nerisalic contain a topical corticosteroid (betamethasone dipropionate and diflucortolone, respectively) and salicylic acid. A left/right study showed that both products have comparable efficacy. It has also been shown that betamethasone dipropionate + salicylic acid ointment has similar efficacy to clobetasol and calcipotriene (calcipotriol) ointments. Betamethasone dipropionate + salicylic acid lotion has similar efficacy to clobetasol lotion. Faster improvement of scaling, itching, and redness was noted with betamethasone dipropionate + salicylic acid lotion compared with betamethasone dipropionate alone. Dovobet (Daivobet) ointment is a fixed-dose combination product containing betamethasone dipropionate and calcipotriene. Clinical studies have shown that it has greater efficacy and a faster speed of onset than the individual components or tacalcitol. Once daily and twice daily treatments have similar efficacy. Psoriasis Area and Severity Index reductions of approximately 40% after 1 week and 70% after 4 weeks of therapy were consistently noted in six large international studies involving >6000 patients. Betamethasone dipropionate + calcipotriene treatment is associated with approximately 75% less adverse cutaneous events as compared with tacalcitol, 50% less compared with calcipotriene, and a similar number as treatment with betamethasone dipropionate. PMID:15109271

  4. [Fiber-reinforced composite in fixed prosthodontics].

    PubMed

    Pilo, R; Abu Rass, Z; Shmidt, A

    2010-07-01

    Fiber reinforced composite (FRC) is composed of resin matrix and fibers filler. Common types of fibers: polyethylene, carbon and glass. Fibers can be continuous and aligned, discontinuous and aligned, discontinuous and randomly oriented. The architecture of the fibers is unidirectional, woven or braided. The two main types are: dry fibers or impregnated. Inclusion of fibers to resin composite increased its average flexural strength in 100-200 MPa. FRC can be utilized by the dentist in direct approach (splinting, temporary winged bridge) or indirect approach (laboratory made fixed partial denture). Laboratory fixed partial denture (FPD) is made from FRC substructure and Hybrid/Microfill particulate composite veneer. Main indications: interim temporary FPD or FPD in cases of questionable abutment teeth, in aesthetic cases where All Ceram FPD is not feasible. Retention is attained by adhesive cementation to minimally prepared teeth or to conventionally prepared teeth; other options are inlay-onlay bridges or hybrid bridges. Contraindications are: poor hygiene, inability to control humidity, parafunction habits, and more than two pontics. Survival rate of FRC FPD over 5 years is 75%, lower compared to porcelain fused to metal FPD which is 95%. Main reasons for failure are: fracture of framework and delamination of the veneer. Part of the failures is repairable. PMID:21485555

  5. Numerical Modeling of Complex Targets for High-Energy- Density Experiments with Ion Beams and other Drivers

    DOE PAGESBeta

    Koniges, Alice; Liu, Wangyi; Lidia, Steven; Schenkel, Thomas; Barnard, John; Friedman, Alex; Eder, David; Fisher, Aaron; Masters, Nathan

    2016-03-01

    We explore the simulation challenges and requirements for experiments planned on facilities such as the NDCX-II ion accelerator at LBNL, currently undergoing commissioning. Hydrodynamic modeling of NDCX-II experiments include certain lower temperature effects, e.g., surface tension and target fragmentation, that are not generally present in extreme high-energy laser facility experiments, where targets are completely vaporized in an extremely short period of time. Target designs proposed for NDCX-II range from metal foils of order one micron thick (thin targets) to metallic foam targets several tens of microns thick (thick targets). These high-energy-density experiments allow for the study of fracture as wellmore » as the process of bubble and droplet formation. We incorporate these physics effects into a code called ALE-AMR that uses a combination of Arbitrary Lagrangian Eulerian hydrodynamics and Adaptive Mesh Refinement. Inclusion of certain effects becomes tricky as we must deal with non-orthogonal meshes of various levels of refinement in three dimensions. A surface tension model used for droplet dynamics is implemented in ALE-AMR using curvature calculated from volume fractions. Thick foam target experiments provide information on how ion beam induced shock waves couple into kinetic energy of fluid flow. Although NDCX-II is not fully commissioned, experiments are being conducted that explore material defect production and dynamics.« less

  6. Numerical Modeling of Complex Targets for High-Energy- Density Experiments with Ion Beams and other Drivers

    NASA Astrophysics Data System (ADS)

    Koniges, Alice; Liu, Wangyi; Lidia, Steven; Schenkel, Thomas; Barnard, John; Friedman, Alex; Eder, David; Fisher, Aaron; Masters, Nathan

    2016-03-01

    We explore the simulation challenges and requirements for experiments planned on facilities such as the NDCX-II ion accelerator at LBNL, currently undergoing commissioning. Hydrodynamic modeling of NDCX-II experiments include certain lower temperature effects, e.g., surface tension and target fragmentation, that are not generally present in extreme high-energy laser facility experiments, where targets are completely vaporized in an extremely short period of time. Target designs proposed for NDCX-II range from metal foils of order one micron thick (thin targets) to metallic foam targets several tens of microns thick (thick targets). These high-energy-density experiments allow for the study of fracture as well as the process of bubble and droplet formation. We incorporate these physics effects into a code called ALE-AMR that uses a combination of Arbitrary Lagrangian Eulerian hydrodynamics and Adaptive Mesh Refinement. Inclusion of certain effects becomes tricky as we must deal with non-orthogonal meshes of various levels of refinement in three dimensions. A surface tension model used for droplet dynamics is implemented in ALE-AMR using curvature calculated from volume fractions. Thick foam target experiments provide information on how ion beam induced shock waves couple into kinetic energy of fluid flow. Although NDCX-II is not fully commissioned, experiments are being conducted that explore material defect production and dynamics.

  7. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1996-06-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.

  8. A beam waveguide linearly polarized KU band feed system

    NASA Astrophysics Data System (ADS)

    Flannery, J. B.

    The linearly polarized KU band beam waveguide feed system considered was designed for use with large Cassegrain antennas typical of those associated with satellite comunications earth stations. The beam waveguide technique permits fixed ground installations of the transmitters and low noise receivers and eliminates the large equipment room usually mounted behind the reflector vertex. The feed system consists of a tapered corrugated wall horn, a matching network, a TE21 mode coupler, three differential phase shifters, a choke coupled rotatable, orthogonal mode transducer, and a servo amplifier system. Attention is given to TE21 mode coupler operation, TE21 mode coupling and directivity, a horn description, a beam wave description, and polarization control.

  9. 46 CFR 130.320 - Electronic position-fixing device.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Electronic position-fixing device. 130.320 Section 130... CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Navigational Equipment § 130.320 Electronic position-fixing device. Each vessel must be equipped with an electronic position-fixing device satisfactory...

  10. 46 CFR 130.320 - Electronic position-fixing device.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Electronic position-fixing device. 130.320 Section 130... CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Navigational Equipment § 130.320 Electronic position-fixing device. Each vessel must be equipped with an electronic position-fixing device satisfactory...

  11. 46 CFR 130.320 - Electronic position-fixing device.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Electronic position-fixing device. 130.320 Section 130... CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Navigational Equipment § 130.320 Electronic position-fixing device. Each vessel must be equipped with an electronic position-fixing device satisfactory...

  12. 49 CFR 587.18 - Dimensions of fixed rigid barrier.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Dimensions of fixed rigid barrier. 587.18 Section 587.18 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... Deformable Barrier § 587.18 Dimensions of fixed rigid barrier. (a) The fixed rigid barrier has a mass of...

  13. 49 CFR 587.18 - Dimensions of fixed rigid barrier.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Dimensions of fixed rigid barrier. 587.18 Section 587.18 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... Deformable Barrier § 587.18 Dimensions of fixed rigid barrier. (a) The fixed rigid barrier has a mass of...

  14. 29 CFR 1910.24 - Fixed industrial stairs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Fixed industrial stairs. 1910.24 Section 1910.24 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.24 Fixed industrial stairs. (a... fixed general industrial stairs. This classification includes interior and exterior stairs...

  15. 29 CFR 1910.24 - Fixed industrial stairs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Fixed industrial stairs. 1910.24 Section 1910.24 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.24 Fixed industrial stairs. (a... fixed general industrial stairs. This classification includes interior and exterior stairs...

  16. 29 CFR 1910.24 - Fixed industrial stairs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Fixed industrial stairs. 1910.24 Section 1910.24 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.24 Fixed industrial stairs. (a... fixed general industrial stairs. This classification includes interior and exterior stairs...

  17. 29 CFR 1910.24 - Fixed industrial stairs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Fixed industrial stairs. 1910.24 Section 1910.24 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.24 Fixed industrial stairs. (a... fixed general industrial stairs. This classification includes interior and exterior stairs...

  18. 29 CFR 1910.24 - Fixed industrial stairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Fixed industrial stairs. 1910.24 Section 1910.24 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.24 Fixed industrial stairs. (a... fixed general industrial stairs. This classification includes interior and exterior stairs...

  19. 46 CFR 121.410 - Electronic position fixing devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Electronic position fixing devices. 121.410 Section 121... AND MISCELLANEOUS SYSTEMS AND EQUIPMENT Navigation Equipment § 121.410 Electronic position fixing devices. A vessel on an oceans route must be equipped with an electronic position fixing device,...

  20. 46 CFR 121.410 - Electronic position fixing devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Electronic position fixing devices. 121.410 Section 121... AND MISCELLANEOUS SYSTEMS AND EQUIPMENT Navigation Equipment § 121.410 Electronic position fixing devices. A vessel on an oceans route must be equipped with an electronic position fixing device,...

  1. 46 CFR 130.320 - Electronic position-fixing device.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Electronic position-fixing device. 130.320 Section 130... CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Navigational Equipment § 130.320 Electronic position-fixing device. Each vessel must be equipped with an electronic position-fixing device satisfactory...

  2. 46 CFR 130.320 - Electronic position-fixing device.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Electronic position-fixing device. 130.320 Section 130... CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Navigational Equipment § 130.320 Electronic position-fixing device. Each vessel must be equipped with an electronic position-fixing device satisfactory...

  3. 47 CFR 25.277 - Temporary fixed earth station operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Temporary fixed earth station operations. 25... SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.277 Temporary fixed earth station operations. (a) When an earth station in the Fixed-Satellite Service is to remain at a single location for...

  4. 47 CFR 25.277 - Temporary fixed earth station operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Temporary fixed earth station operations. 25... SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.277 Temporary fixed earth station operations. (a) When an earth station in the Fixed-Satellite Service is to remain at a single location for...

  5. 47 CFR 25.277 - Temporary fixed earth station operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Temporary fixed earth station operations. 25... SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.277 Temporary fixed earth station operations. (a) When an earth station in the Fixed-Satellite Service is to remain at a single location for...

  6. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  7. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  8. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  9. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  10. 33 CFR 118.65 - Lights on fixed bridges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a...

  11. 48 CFR 46.304 - Fixed-price service contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Fixed-price service... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.304 Fixed-price service contracts. The contracting officer shall insert the clause at 52.246-4, Inspection of Services—Fixed-Price, in...

  12. 48 CFR 1852.216-83 - Fixed price incentive.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Fixed price incentive... 1852.216-83 Fixed price incentive. As prescribed in 1816.406-70(c), insert the following clause: Fixed Price Incentive (OCT 1996) The target cost of this contract is $___. The Target profit of this...

  13. 48 CFR 1828.370 - Fixed-price contract clauses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Fixed-price contract... ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 1828.370 Fixed-price contract... Risk, in all negotiated fixed-price contracts for the development, production,...

  14. 48 CFR 47.104-2 - Fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price contracts. 47... MANAGEMENT TRANSPORTATION General 47.104-2 Fixed-price contracts. (a) F.o.b. destination. 49 U.S.C. 10721 and 13712 rates do not apply to shipments under fixed-price f.o.b. destination contracts (delivered...

  15. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts....

  16. 48 CFR 1828.370 - Fixed-price contract clauses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Fixed-price contract... ADMINISTRATION GENERAL CONTRACTING REQUIREMENTS BONDS AND INSURANCE Insurance 1828.370 Fixed-price contract... Risk, in all negotiated fixed-price contracts for the development, production,...

  17. 48 CFR 31.102 - Fixed-price contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Fixed-price contracts. 31... CONTRACTING REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Applicability 31.102 Fixed-price contracts. The applicable subparts of part 31 shall be used in the pricing of fixed-price contracts,...

  18. 48 CFR 46.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Fixed-price supply... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.302 Fixed-price supply contracts. The contracting officer shall insert the clause at 52.246-2, Inspection of Supplies—Fixed-Price, in solicitations...

  19. 48 CFR 46.304 - Fixed-price service contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price service... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.304 Fixed-price service contracts. The contracting officer shall insert the clause at 52.246-4, Inspection of Services—Fixed-Price, in...

  20. 48 CFR 47.104-2 - Fixed-price contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Fixed-price contracts. 47... MANAGEMENT TRANSPORTATION General 47.104-2 Fixed-price contracts. (a) F.o.b. destination. 49 U.S.C. 10721 and 13712 rates do not apply to shipments under fixed-price f.o.b. destination contracts (delivered...

  1. 48 CFR 52.243-1 - Changes-Fixed-Price.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Changes-Fixed-Price. 52....243-1 Changes—Fixed-Price. As prescribed in 43.205(e), insert the following clause: Changes—Fixed-Price (AUG 1987) (a) The Contracting Officer may at any time, by written order, and without notice...

  2. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts....

  3. 48 CFR 52.243-1 - Changes-Fixed-Price.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Changes-Fixed-Price. 52....243-1 Changes—Fixed-Price. As prescribed in 43.205(e), insert the following clause: Changes—Fixed-Price (AUG 1987) (a) The Contracting Officer may at any time, by written order, and without notice...

  4. 48 CFR 52.243-1 - Changes-Fixed-Price.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Changes-Fixed-Price. 52....243-1 Changes—Fixed-Price. As prescribed in 43.205(e), insert the following clause: Changes—Fixed-Price (AUG 1987) (a) The Contracting Officer may at any time, by written order, and without notice...

  5. 48 CFR 46.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price supply... CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 46.302 Fixed-price supply contracts. The contracting officer shall insert the clause at 52.246-2, Inspection of Supplies—Fixed-Price, in solicitations...

  6. 48 CFR 52.243-1 - Changes-Fixed-Price.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Changes-Fixed-Price. 52....243-1 Changes—Fixed-Price. As prescribed in 43.205(e), insert the following clause: Changes—Fixed-Price (AUG 1987) (a) The Contracting Officer may at any time, by written order, and without notice...

  7. 48 CFR 31.102 - Fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Fixed-price contracts. 31... CONTRACTING REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Applicability 31.102 Fixed-price contracts. The applicable subparts of part 31 shall be used in the pricing of fixed-price contracts,...

  8. 50 CFR 660.219 - Fixed gear identification and marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear identification and marking. 660.219 Section 660.219 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Groundfish-Limited Entry Fixed Gear Fisheries § 660.219 Fixed gear identification and marking. (a)...

  9. 29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet...

  10. 29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet...

  11. 29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet...

  12. 29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet...

  13. Charm and beauty measurements at Fermilab fixed target

    SciTech Connect

    Mishra, C.S.

    1993-10-01

    Eighteen months after a successful run of the Fermilab fixed target program, interesting results from several experiments are available. This is the first time that more than one Fermilab fixed target experiment has reported the observation of beauty mesons. In this paper we review recent results from charm and beauty fixed target experiments at Fermilab.

  14. 10 CFR 600.29 - Fixed obligation awards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Fixed obligation awards. 600.29 Section 600.29 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS FINANCIAL ASSISTANCE RULES General § 600.29 Fixed obligation awards. (a) General. This section contains provisions applicable to the award of financial assistance instruments on a fixed amount...

  15. 47 CFR 101.125 - Temporary fixed antenna height restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Temporary fixed antenna height restrictions... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.125 Temporary fixed antenna height restrictions. The overall antenna structure heights employed by mobile stations in the...

  16. 47 CFR 101.125 - Temporary fixed antenna height restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Temporary fixed antenna height restrictions... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.125 Temporary fixed antenna height restrictions. The overall antenna structure heights employed by mobile stations in the...

  17. 47 CFR 101.125 - Temporary fixed antenna height restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Temporary fixed antenna height restrictions... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.125 Temporary fixed antenna height restrictions. The overall antenna structure heights employed by mobile stations in the...

  18. 47 CFR 101.125 - Temporary fixed antenna height restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Temporary fixed antenna height restrictions... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.125 Temporary fixed antenna height restrictions. The overall antenna structure heights employed by mobile stations in the...

  19. 47 CFR 101.125 - Temporary fixed antenna height restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Temporary fixed antenna height restrictions... SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.125 Temporary fixed antenna height restrictions. The overall antenna structure heights employed by mobile stations in the...

  20. 48 CFR 1852.216-83 - Fixed price incentive.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Fixed price incentive. 1852... 1852.216-83 Fixed price incentive. As prescribed in 1816.406-70(c), insert the following clause: Fixed Price Incentive (OCT 1996) The target cost of this contract is $___. The Target profit of this...

  1. 47 CFR 15.307 - Coordination with fixed microwave service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Coordination with fixed microwave service. 15... Unlicensed Personal Communications Service Devices § 15.307 Coordination with fixed microwave service. (a... Private Operational-Fixed Microwave Service (OFS) operating under part 101 of this chapter to...

  2. 47 CFR 15.307 - Coordination with fixed microwave service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Coordination with fixed microwave service. 15... Unlicensed Personal Communications Service Devices § 15.307 Coordination with fixed microwave service. (a... Private Operational-Fixed Microwave Service (OFS) operating under part 101 of this chapter to...

  3. 47 CFR 25.277 - Temporary fixed earth station operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Temporary fixed earth station operations. 25... SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.277 Temporary fixed earth station operations. (a) When an earth station in the Fixed-Satellite Service is to remain at a single location for...

  4. 47 CFR 25.277 - Temporary fixed earth station operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Temporary fixed earth station operations. 25... SERVICES SATELLITE COMMUNICATIONS Technical Operations § 25.277 Temporary fixed earth station operations. (a) When an earth station in the Fixed-Satellite Service is to remain at a single location for...

  5. 46 CFR 108.631 - Fixed fire extinguishing system controls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... DRILLING UNITS DESIGN AND EQUIPMENT Equipment Markings and Instructions § 108.631 Fixed fire extinguishing system controls. (a) Each cabinet or space that contains a valve, control, or manifold of a fixed fire... 46 Shipping 4 2011-10-01 2011-10-01 false Fixed fire extinguishing system controls....

  6. 46 CFR 108.631 - Fixed fire extinguishing system controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DRILLING UNITS DESIGN AND EQUIPMENT Equipment Markings and Instructions § 108.631 Fixed fire extinguishing system controls. (a) Each cabinet or space that contains a valve, control, or manifold of a fixed fire... 46 Shipping 4 2010-10-01 2010-10-01 false Fixed fire extinguishing system controls....

  7. Automated beam builder

    NASA Technical Reports Server (NTRS)

    Muench, W. K.

    1980-01-01

    Requirements for the space fabrication of large space structures are considered with emphasis on the design, development, manufacture, and testing of a machine which automatically produces a basic building block aluminum beam. Particular problems discussed include those associated with beam cap forming; brace storage, dispensing, and transporting; beam component fastening; and beam cut-off. Various critical process tests conducted to develop technology for a machine to produce composite beams are also discussed.

  8. BEAM HALO IN PROTON LINAC BEAMS

    SciTech Connect

    T. WANGLER; K. CRANDALL

    2000-08-01

    In this paper we review the present picture of km halo in proton linacs. Space-charge forces acting in mismatched beams have been identified as a major cause of beam-halo. We present a definition of halo based on a ratio of moments of the distribution of the beam coordinates. We find from our initial studies that for halo detined in this way, a beam can have rms emittance growth without halo growth, but halo growth is always accompanied by rms emittance growth. We describe the beam-halo experiment that is in preparation at Los Alamos, which will address questions about the beam profiles, maximum particle amplitudes, and rms emittance growth associated with the halo.

  9. Interferometric Measurement for Improved Understanding of Boundary Effects in Micromachined Beams

    SciTech Connect

    Bitsie, Fernando; Jensen, Brian D.; de Boer, Maarten

    1999-07-15

    Micromachined beams are commonly used to measure material properties in MEMS. Such measurements are complicated by the fact that boundary effects at the ends of the beams have a significant effect on the properties being measured. In an effort to improve the accuracy and resolution of such measurements, we are conducting a study of support post compliance in cantilever and fixed-fixed beams. Three different support post designs have been analyzed by finite element modeling. The results are then compared to measurements made on actual devices using interferometry. Using this technique, the accuracy of measurements of Young's modulus has been improved. Continuing work will also improve the measurement of residual stress.

  10. Formation of slow molecules in chemical reactions in crossed molecular beams

    NASA Astrophysics Data System (ADS)

    Tscherbul, T. V.; Barinovs, Ğ.; Kłos, J.; Krems, R. V.

    2008-08-01

    We demonstrate that chemical reactions in collisions of molecular beams can generally produce low-velocity molecules in the laboratory-fixed frame. Our analysis shows that collisions of beams may simultaneously yield slow reactant molecules and slow products. The reaction products are formed in selected rovibrational states and scattered in a specific direction, which can be controlled by tuning the kinetic energies of the incident beams and the angle between the beams. Our calculations indicate that chemical reactions of polar alkali-metal dimers are barrierless and we suggest that chemical reactions involving alkali-metal dimers may be particularly suitable for producing slow molecules in crossed beams.

  11. Calibration of a proton beam energy monitor

    SciTech Connect

    Moyers, M. F.; Coutrakon, G. B.; Ghebremedhin, A.; Shahnazi, K.; Koss, P.; Sanders, E.

    2007-06-15

    Delivery of therapeutic proton beams requires an absolute energy accuracy of {+-}0.64 to 0.27 MeV for patch fields and a relative energy accuracy of {+-}0.10 to 0.25 MeV for tailoring the depth dose distribution using the energy stacking technique. Achromatic switchyard tunes, which lead to better stability of the beam incident onto the patient, unfortunately limit the ability of switchyard magnet tesla meters to verify the correct beam energy within the tolerances listed above. A new monitor to measure the proton energy before each pulse is transported through the switchyard has been installed into a proton synchrotron. The purpose of this monitor is to correct and/or inhibit beam delivery when the measured beam energy is outside of the tolerances for treatment. The monitor calculates the beam energy using data from two frequency and eight beam position monitors that measure the revolution frequency of the proton bunches and the effective offset of the orbit from the nominal radius of the synchrotron. The new energy monitor has been calibrated by measuring the range of the beam through water and comparing with published range-energy tables for various energies. A relationship between depth dose curves and range-energy tables was first determined using Monte Carlo simulations of particle transport and energy deposition. To reduce the uncertainties associated with typical scanning water phantoms, a new technique was devised in which the beam energy was scanned while fixed thickness water tanks were sandwiched between two fixed parallel plate ionization chambers. Using a multitude of tank sizes, several energies were tested to determine the nominal accelerator orbit radius. After calibration, the energy reported by the control system matched the energy derived by range measurements to better than 0.72 MeV for all nine energies tested between 40 and 255 MeV with an average difference of -0.33 MeV. A study of different combinations of revolution frequency and radial

  12. Calibration of a proton beam energy monitor.

    PubMed

    Moyers, M F; Coutrakon, G B; Ghebremedhin, A; Shahnazi, K; Koss, P; Sanders, E

    2007-06-01

    Delivery of therapeutic proton beams requires an absolute energy accuracy of +/-0.64 to 0.27 MeV for patch fields and a relative energy accuracy of +/-0.10 to 0.25 MeV for tailoring the depth dose distribution using the energy stacking technique. Achromatic switchyard tunes, which lead to better stability of the beam incident onto the patient, unfortunately limit the ability of switchyard magnet tesla meters to verify the correct beam energy within the tolerances listed above. A new monitor to measure the proton energy before each pulse is transported through the switchyard has been installed into a proton synchrotron. The purpose of this monitor is to correct and/or inhibit beam delivery when the measured beam energy is outside of the tolerances for treatment. The monitor calculates the beam energy using data from two frequency and eight beam position monitors that measure the revolution frequency of the proton bunches and the effective offset of the orbit from the nominal radius of the synchrotron. The new energy monitor has been calibrated by measuring the range of the beam through water and comparing with published range-energy tables for various energies. A relationship between depth dose curves and range-energy tables was first determined using Monte Carlo simulations of particle transport and energy deposition. To reduce the uncertainties associated with typical scanning water phantoms, a new technique was devised in which the beam energy was scanned while fixed thickness water tanks were sandwiched between two fixed parallel plate ionization chambers. Using a multitude of tank sizes, several energies were tested to determine the nominal accelerator orbit radius. After calibration, the energy reported by the control system matched the energy derived by range measurements to better than 0.72 MeV for all nine energies tested between 40 and 255 MeV with an average difference of -0.33 MeV. A study of different combinations of revolution frequency and radial

  13. Scaling fixed-field alternating gradient accelerators with a small orbit excursion.

    PubMed

    Machida, Shinji

    2009-10-16

    A novel scaling type of fixed-field alternating gradient (FFAG) accelerator is proposed that solves the major problems of conventional scaling and nonscaling types. This scaling FFAG accelerator can achieve a much smaller orbit excursion by taking a larger field index k. A triplet focusing structure makes it possible to set the operating point in the second stability region of Hill's equation with a reasonable sensitivity to various errors. The orbit excursion is about 5 times smaller than in a conventional scaling FFAG accelerator and the beam size growth due to typical errors is at most 10%. PMID:19905700

  14. Scaling Fixed-Field Alternating Gradient Accelerators with a Small Orbit Excursion

    SciTech Connect

    Machida, Shinji

    2009-10-16

    A novel scaling type of fixed-field alternating gradient (FFAG) accelerator is proposed that solves the major problems of conventional scaling and nonscaling types. This scaling FFAG accelerator can achieve a much smaller orbit excursion by taking a larger field index k. A triplet focusing structure makes it possible to set the operating point in the second stability region of Hill's equation with a reasonable sensitivity to various errors. The orbit excursion is about 5 times smaller than in a conventional scaling FFAG accelerator and the beam size growth due to typical errors is at most 10%.

  15. Tevatron beam-beam compensation project progress

    SciTech Connect

    Shiltsev, V.; Zhang, X.L.; Kuznetsov, G.; Pfeffer, H.; Saewert, G.; Zimmermann, F.; Tiunov, M.; Bishofberger, K.; Bogdanov, I.; Kashtanov, E.; Kozub, S.; Sytnik, V.; Tkachenko, L.; /Serpukhov, IHEP

    2005-05-01

    In this paper, we report the progress of the Tevatron Beam-Beam Compensation (BBC) project [1]. Electron beam induced proton and antiproton tuneshifts have been reported in [2], suppression of an antiproton emittance growth has been observed, too [1]. Currently, the first electron lens (TEL1) is in operational use as the Tevatron DC beam cleaner. We have made a lot of the upgrades to improve its stability [3]. The 2nd Tevatron electron lens (TEL2) is under the final phase of development and preparation for installation in the Tevatron.

  16. Fixed target experiments at the Fermilab Tevatron

    DOE PAGESBeta

    Gutierrez, Gaston; Reyes, Marco A.

    2014-11-10

    This paper presents a review of the study of Exclusive Central Production at a Center of Mass energy of √s = 40 GeV at the Fermilab Fixed Target program. In all reactions reviewed in this paper, protons with an energy of 800 GeV were extracted from the Tevatron accelerator at Fermilab and directed to a Liquid Hydrogen target. The states reviewed include π⁺π⁻, K⁰s K⁰s, K⁰s K±π∓, φφ and D*±. Partial Wave Analysis results will be presented on the light states but only the cross-section will be reviewed in the diffractive production of D*±.

  17. Quality of fixed prosthodontics after 15 years.

    PubMed

    Glantz, P O; Nilner, K; Jendresen, M D; Sundberg, H

    1993-08-01

    Interviews and/or clinical examinations by means of the California Dental Association quality evaluation system were carried out in a group of persons who had received extensive restorative treatments with fixed partial dentures 15 years before this study. The studied group consisted of 77 persons who agreed to participate from an original group of 150 persons selected at random from the Swedish Dental Insurance System records. Of the original group 20 had died, 17 were not traceable or not able to participate for medical reasons, and 36 declined to participate. Thirty-two per cent of the recorded reconstructions had been lost, and 8% partially lost during the 15-year period. Thirty-five per cent of the reconstructions were rated as Satisfactory, whereas the remaining ones had mixed clinical quality ratings. Failures and Not Acceptable quality ratings were found to be caused mainly by fractures, loss of retention, and/or dental caries. PMID:8237309

  18. Fixed drug eruption due to levocetirizine.

    PubMed

    Jhaj, Ratinder; Asati, Dinesh Prasad; Chaudhary, Deepa

    2016-01-01

    A fixed drug eruption (FDE) is a cutaneous adverse drug reaction due to Type IV or delayed cell-mediated hypersensitivity. Antihistamines, which antagonize the action of histamine during an allergic reaction by blocking the H1 histamine receptors, are used routinely for the treatment of various allergic disorders such as urticaria, eczemas, and also in itchy lesions of skin like scabies. Levocetirizine, an active (R)-enantiomer of cetirizine, is a newer or second generation antihistamine, with more specific actions and fewer side effects, including cutaneous reactions. FDE due to levocetirizine as well as with cetirizine are rare. We report a case of levocetirizine induced FDE in a 49-year-old male patient with scabies. The patient had a history of cetirizine induced FDE in the past. PMID:27440959

  19. Ursodeoxycholic acid induced generalized fixed drug eruption.

    PubMed

    Ozkol, Hatice Uce; Calka, Omer; Dulger, Ahmet Cumhur; Bulut, Gulay

    2014-09-01

    Fixed drug eruption (FDE) is a rare form of drug allergies that recur at the same cutaneous or mucosal site in every usage of drug. Single or multiple round, sharply demarcated and dusky red plaques appear soon after drug exposure. Ursodeoxycholic acid (UDCA: 3α,7β-dihydroxy-5β-cholanic acid) is used for the treatment of cholestatic liver diseases. Some side effects may be observed, such as diarrhea, dyspepsia, pruritus and headaches. We encountered only three cases of lichenoid reaction regarding the use of UDCA among previous studies. In this article, we reported a generalized FDE case related to UDCA intake in a 59-year-old male patient with cholestasis for the first time in the literature. PMID:24147950

  20. Fixed target experiments at the Fermilab Tevatron

    SciTech Connect

    Gutierrez, Gaston; Reyes, Marco A.

    2014-11-10

    This paper presents a review of the study of Exclusive Central Production at a Center of Mass energy of √s = 40 GeV at the Fermilab Fixed Target program. In all reactions reviewed in this paper, protons with an energy of 800 GeV were extracted from the Tevatron accelerator at Fermilab and directed to a Liquid Hydrogen target. The states reviewed include π⁺π⁻, K⁰s K⁰s, K⁰s K±π, φφ and D. Partial Wave Analysis results will be presented on the light states but only the cross-section will be reviewed in the diffractive production of D.

  1. Secure Computation with Fixed-Point Numbers

    NASA Astrophysics Data System (ADS)

    Catrina, Octavian; Saxena, Amitabh

    Secure computation is a promising approach to business problems in which several parties want to run a joint application and cannot reveal their inputs. Secure computation preserves the privacy of input data using cryptographic protocols, allowing the parties to obtain the benefits of data sharing and at the same time avoid the associated risks. These business applications need protocols that support all the primitive data types and allow secure protocol composition and efficient application development. Secure computation with rational numbers has been a challenging problem. We present in this paper a family of protocols for multiparty computation with rational numbers using fixed-point representation. This approach offers more efficient solutions for secure computation than other usual representations.

  2. Fixed drug eruption due to levocetirizine

    PubMed Central

    Jhaj, Ratinder; Asati, Dinesh Prasad; Chaudhary, Deepa

    2016-01-01

    A fixed drug eruption (FDE) is a cutaneous adverse drug reaction due to Type IV or delayed cell-mediated hypersensitivity. Antihistamines, which antagonize the action of histamine during an allergic reaction by blocking the H1 histamine receptors, are used routinely for the treatment of various allergic disorders such as urticaria, eczemas, and also in itchy lesions of skin like scabies. Levocetirizine, an active (R)-enantiomer of cetirizine, is a newer or second generation antihistamine, with more specific actions and fewer side effects, including cutaneous reactions. FDE due to levocetirizine as well as with cetirizine are rare. We report a case of levocetirizine induced FDE in a 49-year-old male patient with scabies. The patient had a history of cetirizine induced FDE in the past. PMID:27440959

  3. Partial gauge fixing and equivariant cohomology

    NASA Astrophysics Data System (ADS)

    Ferrari, Frank

    2014-05-01

    Given a gauge theory with gauge group G, it is sometimes useful to find an equivalent formulation in terms of a nontrivial gauge subgroup H ⊂G. This amounts to fixing the gauge partially from G down to H. We study this problem systematically, both from the algebraic and from the path integral points of view. We find that the usual BRST cohomology must be replaced by an equivariant version and that the ghost Lagrangian must always include quartic ghost terms, even at tree level. Both the Cartan and Weil models for equivariant cohomology play a role and find natural interpretations within the physics framework. Applications include the construction of D-brane models of emergent space, the 't Hooft Abelian projection scenario in quantum chromodynamics and the formulation of the low-energy effective theories of grand unified models.

  4. Settling of fixed erythrocyte suspension droplets

    NASA Technical Reports Server (NTRS)

    Omenyi, S. N.; Snyder, R. S.

    1983-01-01

    It is pointed out that when particles behave collectively rather than individually, the fractionation of micron-size particles on the basis of size, density, and surface characteristics by centrifugation and electrophoresis is hindered. The formation and sedimentation of droplets containing particles represent an extreme example of collective behavior and pose a major problem for these separation methods when large quantities of particles need to be fractionated. Experiments are described that measure droplet sizes and settling rates for a variety of particles and droplets. Expressions relating the particle concentration in a drop to measurable quantities of the fluids and particles are developed. The number of particles in each droplet is then estimated, together with the effective droplet density. Red blood cells from different animals fixed in glutaraldehyde provide model particle groups.

  5. Fixed Eigenvector Analysis of Thermographic NDE Data

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Winfree, William P.

    2011-01-01

    Principal Component Analysis (PCA) has been shown effective for reducing thermographic NDE data. This paper will discuss an alternative method of analysis that has been developed where a predetermined set of eigenvectors is used to process the thermal data from both reinforced carbon-carbon (RCC) and graphiteepoxy honeycomb materials. These eigenvectors can be generated either from an analytic model of the thermal response of the material system under examination, or from a large set of experimental data. This paper provides the details of the analytic model, an overview of the PCA process, as well as a quantitative signal-to-noise comparison of the results of performing both conventional PCA and fixed eigenvector analysis on thermographic data from two specimens, one Reinforced Carbon-Carbon with flat bottom holes and the second a sandwich construction with graphite-epoxy face sheets and aluminum honeycomb core.

  6. Meprobamate-induced fixed drug eruption.

    PubMed

    Zaïem, Ahmed; Kaabi, Widd; Badri, Talel; Lakhoua, Ghozlane; Sahnoun, Rym; Kastalli, Sarrah; Daghfous, Riadh; Lakhal, Mohamed; El Aidli, Sihem

    2014-01-01

    Meprobamate is usually a safe drug prescribed for anxiety disorders. Fixed drug eruption (FDE) is an exceptional cutaneous adverse effect of this drug. We report a case of FDE induced by meprobamate with positive patch test. A 22-year-old woman was prescribed for depression meprobamate, aceprometazine, valpromide and lorazepam. On the second day of treatment, the patient presented red erythematous and pruriginous plaques in the limbs and the face. After stopping the previous treatment, the patient's lesions resolved completely within 3 weeks with residual pigmentation. One month later, patch tests were performed and were positive to meprobamate. Exceptional cases of FDE were reported in literature with meprobamate. None has reported the use of patch test to confirm the diagnosis. PMID:24446836

  7. Link and subgraph likelihoods in random undirected networks with fixed and partially fixed degree sequences

    NASA Astrophysics Data System (ADS)

    Foster, Jacob G.; Foster, David V.; Grassberger, Peter; Paczuski, Maya

    2007-10-01

    The simplest null models for networks, used to distinguish significant features of a particular network from a priori expected features, are random ensembles with the degree sequence fixed by the specific network of interest. These “fixed degree sequence” (FDS) ensembles are, however, famously resistant to analytic attack. In this paper we introduce ensembles with partially-fixed degree sequences (PFDS) and compare analytic results obtained for them with Monte Carlo results for the FDS ensemble. These results include link likelihoods, subgraph likelihoods, and degree correlations. We find that local structural features in the FDS ensemble can be reasonably well estimated by simultaneously fixing only the degrees of a few nodes, in addition to the total number of nodes and links. As test cases we use two protein interaction networks (Escherichia coli, Saccharomyces cerevisiae), the internet on the autonomous system (AS) level, and the World Wide Web. Fixing just the degrees of two nodes gives the mean neighbor degree as a function of node degree, ⟨k'⟩k , in agreement with results explicitly obtained from rewiring. For power law degree distributions, we derive the disassortativity analytically. In the PFDS ensemble the partition function can be expanded diagrammatically. We obtain an explicit expression for the link likelihood to lowest order, which reduces in the limit of large, sparse undirected networks with L links and with kmax≪L to the simple formula P(k,k')=kk'/(2L+kk') . In a similar limit, the probability for three nodes to be linked into a triangle reduces to the factorized expression PΔ(k1,k2,k3)=P(k1,k2)P(k1,k3)P(k2,k3) .

  8. Do foliar endophytic bacteria fix nitrogen?

    NASA Astrophysics Data System (ADS)

    Kueppers, L. M.; Moyes, A. B.; Frank, C.; Pett-Ridge, J.; Carper, D.; Vandehey, N.; O'Neil, J.; Dekas, A.

    2015-12-01

    Endophytic microorganisms - bacteria and fungi that live inside healthy plant tissue - are a relatively unexplored source of functional diversity in natural ecosystems. Prior to modern sequencing technology, detecting uncultured endophytic bacteria and assessing their putative functions was challenging. However, recent work has revealed a remarkable diversity of as yet non-culturable endophytic taxa and is beginning to identify functional roles within plant microbiomes. We recently examined bacterial communities in the foliage of a long-lived, high-elevation conifer species, limber pine (Pinus flexilis), and discovered a community strongly dominated by acetic acid bacteria (Acetobacteraceae), with several taxa closely related to known nitrogen fixers. Given limber pine's status as a pioneer species that is able to grow in low fertility soils, we hypothesized that this bacterial community has a potential functional role in fixing atmospheric nitrogen, providing a source of this limiting nutrient to the host tree. We used the radioisotope 13N2 to confirm that N2 rapidly diffuses into pine needles, where it could potentially be fixed. With an acetylene reduction assay we confirmed nitrogenase enzyme activity inside excised twigs 4 times over a growing season, and estimate potential rates of N2 fixation at 0.1 nmol N2 g needle-1 hr-1. Scaled to the stand level, this N input could be on the order of ~20 mg N m-2 d-1 over a growing season. While these rates are low, the long lifespan of individual trees (~1000 years) makes them biologically meaningful. Still, measured rates of acetylene reduction and bulk 15N2 incorporation are quite variable in space and time. Much work remains to better characterize the plant-microbial interactions in this system, including the rates of nitrogen fixation and their variability over the growing season, across edaphic conditions, among host species, and through plant development; and to determine which community members are responsible

  9. ION BEAM COLLIMATOR

    DOEpatents

    Langsdorf, A.S. Jr.

    1957-11-26

    A device is described for defining a beam of high energy particles wherein the means for defining the beam in the horizontal and vertical dimension are separately adjustable and the defining members are internally cooled. In general, the device comprises a mounting block having a central opening through which the beam is projected, means for rotatably supporting two pairs of beam- forming members, passages in each member for the flow of coolant; the beam- forming members being insulated from each other and the block, and each having an end projecting into the opening. The beam-forming members are adjustable and may be cooperatively positioned to define the beam passing between the end of the members. To assist in projecting and defining the beam, the member ends have individual means connected thereto for indicating the amount of charge collected thereon due to beam interception.

  10. Limitations on area compression of beams from pierce guns

    SciTech Connect

    Yakovlev, V.P.; Nezhevenko, O.A.

    1999-05-01

    An important limitation for rf sources such as klystrons and magnicons, designed for 10{close_quote}s of MW power outputs at cm-wavelengths, is the transverse electron beam size. Cathode current density limits require high beam area compressions to obtain small transverse beam areas for fixed currents. This paper discusses the limitations to high beam area compression, namely geometrical aberrations and thermal spread in transverse velocities. Compensation can oftentimes be introduced for aberrations, but thermal velocity spread presents a fundamental limitation. Examples where subtle compensation strategies were employed are discussed for three guns with 100 MW beam power, and area compressions greater than 2000:1. Two of these guns have already been built. A clear determination of effective cathode temperature has yet to be found experimentally, but possible means to measure it are discussed. {copyright} {ital 1999 American Institute of Physics.}

  11. Computed tomographic beam-hardening artefacts: mathematical characterization and analysis

    PubMed Central

    Park, Hyoung Suk; Chung, Yong Eun; Seo, Jin Keun

    2015-01-01

    This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. PMID:25939628

  12. Computed tomographic beam-hardening artefacts: mathematical characterization and analysis.

    PubMed

    Park, Hyoung Suk; Chung, Yong Eun; Seo, Jin Keun

    2015-06-13

    This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. PMID:25939628

  13. High Transverse Momentum Direct Photon Production at Fermilab Fixed-Target Energies

    SciTech Connect

    Apanasevich, Leonard

    2005-05-01

    This thesis describes a study of the production of high transverse momentum direct photons and {pi}{sup 0} mesons by proton beams at 530 and 800 GeV/c and {pi}{sup -} beams at 515 GeV/c incident on beryllium, copper, and liquid hydrogen targets. The data were collected by Fermilab experiment E706 during the 1990 and 1991-92 fixed target runs. The apparatus included a large, finely segmented lead and liquid argon electromagnetic calorimeter and a charged particle spectrometer featuring silicon strip detectors in the target region and proportional wire chambers and drift tubes downstream of a large aperture analysis magnet. The inclusive cross sections are presented as functions of transverse momentum and rapidity. The measurements are compared with next-to-leading order perturbative QCD calculations and to results from previous experiments.

  14. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the beam current limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beamline below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described. {copyright} {ital 1997 American Institute of Physics.}

  15. Beam position monitor

    DOEpatents

    Alkire, Randy W.; Rosenbaum, Gerold; Evans, Gwyndaf

    2003-07-22

    An apparatus for determining the position of an x-ray beam relative to a desired beam axis. Where the apparatus is positioned along the beam path so that a thin metal foil target intersects the x-ray beam generating fluorescent radiation. A PIN diode array is positioned so that a portion of the fluorescent radiation is intercepted by the array resulting in an a series of electrical signals from the PIN diodes making up the array. The signals are then analyzed and the position of the x-ray beam is determined relative to the desired beam path.

  16. Pyramid beam splitter

    DOEpatents

    McKeown, Mark H.; Beason, Steven C.; Fairer, George

    1992-01-01

    The apparatus of the present invention provides means for obtaining accurate, dependable, measurement of bearings and directions for geologic mapping in subterranean shafts, such as, for example, nuclear waste storage investigations. In operation, a laser beam is projected along a reference bearing. A pyramid is mounted such that the laser beam is parallel to the pyramid axis and can impinge on the apex of the pyramid thus splitting the beam several ways into several beams at right angles to each other and at right angles to the reference beam. The pyramid is also translatable and rotatable in a plane perpendicular to the reference beam.

  17. Nonlinear bending models for beams and plates

    PubMed Central

    Antipov, Y. A.

    2014-01-01

    A new nonlinear model for large deflections of a beam is proposed. It comprises the Euler–Bernoulli boundary value problem for the deflection and a nonlinear integral condition. When bending does not alter the beam length, this condition guarantees that the deflected beam has the original length and fixes the horizontal displacement of the free end. The numerical results are in good agreement with the ones provided by the elastica model. Dynamic and two-dimensional generalizations of this nonlinear one-dimensional static model are also discussed. The model problem for an inextensible rectangular Kirchhoff plate, when one side is clamped, the opposite one is subjected to a shear force, and the others are free of moments and forces, is reduced to a singular integral equation with two fixed singularities. The singularities of the unknown function are examined, and a series-form solution is derived by the collocation method in terms of the associated Jacobi polynomials. The procedure requires solving an infinite system of linear algebraic equations for the expansion coefficients subject to the inextensibility condition. PMID:25294960

  18. Ion exchanger in the brain: Quantitative analysis of perineuronally fixed anionic binding sites suggests diffusion barriers with ion sorting properties

    NASA Astrophysics Data System (ADS)

    Morawski, Markus; Reinert, Tilo; Meyer-Klaucke, Wolfram; Wagner, Friedrich E.; Tröger, Wolfgang; Reinert, Anja; Jäger, Carsten; Brückner, Gert; Arendt, Thomas

    2015-12-01

    Perineuronal nets (PNs) are a specialized form of brain extracellular matrix, consisting of negatively charged glycosaminoglycans, glycoproteins and proteoglycans in the direct microenvironment of neurons. Still, locally immobilized charges in the tissue have not been accessible so far to direct observations and quantifications. Here, we present a new approach to visualize and quantify fixed charge-densities on brain slices using a focused proton-beam microprobe in combination with ionic metallic probes. For the first time, we can provide quantitative data on the distribution and net amount of pericellularly fixed charge-densities, which, determined at 0.4-0.5 M, is much higher than previously assumed. PNs, thus, represent an immobilized ion exchanger with ion sorting properties high enough to partition mobile ions in accord with Donnan-equilibrium. We propose that fixed charge-densities in the brain are involved in regulating ion mobility, the volume fraction of extracellular space and the viscosity of matrix components.

  19. AGS RESONANT EXTRACTION WITH HIGH INTENSITY BEAMS.

    SciTech Connect

    AHRENS,L.; BROWN,K.; GLENN,J.W.; ROSER,T.; TSOUPAS,N.; VANASSELT,W.

    1999-03-29

    The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams.[1] Learning to extract and transport these higher intensity beams has required a process of careful modeling and experimentation. We have had to learn how to correct for various instabilities and how to better match extraction and the transport lines to the higher emittance beams being accelerated in the AGS. Techniques employed include ''RF'' methods to smooth out momentum distributions and fine structure. We will present results of detailed multi-particle tracking modeling studies which enabled us to develop a clear understanding of beam loss mechanisms in the transport and extraction process. We will report on our status, experiences, and the present understanding of the intensity limitations imposed by resonant extraction and transport to fixed target stations.

  20. RD30 - study of an optical trigger proposed for a beauty search in fixed target mode at the LHC

    NASA Astrophysics Data System (ADS)

    Kochowski, C.; Charpak, G.; Giomataris, Y.; Joseph, C.; Perroud, J.-P.; Tran, M. T.; Chipaux, R.; Delbart, A.; Derre, J.; Lemoigne, Y.; Loucatos, S.; Rebourgeard, Ph.; Kaplan, D. M.; Hill, T.; Rosenberg, E. I.; Chrisman, D.; Cline, D.; Rhoades, J.; Atac, M.; Buzuloiu, V.; Vlad, O. G.; Coltuc, D.; RD30 Collaboration

    1994-11-01

    The optical discriminator is based on the detection of Cherenkov light produced and trapped in a thin, spherical, crystal shell. It is only sensitive to charged particles with a non-zero impact parameter relative to the centre of the crystal sphere. The properties of this device, the results of tests in a particle beam and the expected performance in a fast selection of B events in fixed target experiments are reported.

  1. Beam-beam issues in asymmetric colliders

    SciTech Connect

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  2. Beam lifetime and beam brightness in ALS

    SciTech Connect

    Kim, C.; Jackson, A.; Warwick, A.

    1995-04-01

    Beam lifetime in ALS is dominated by the Touschek scattering. Measurements of lifetime in single-bunch mode with estimates of bunch dimensions obtained from undulator radiation data are consistent with expectations (t=1.8 hours at 1.25 mA per bunch). However, the lifetime is significantly longer in multi-bunch mode (t=ll hours at 400 mA per 320 bunches). This discrepancy has been traced to an increase in the momentum spread and bunch length in the beam caused by longitudinal coupled-bunch motions driven by higher-order modes in the rf cavities. The increased momentum spread leads to a significant degradation in the undulator spectral performance. Feedback stabilization of the coupled-bunch motion improves the spectral characteristics of the undulator beam at the expense of beam lifetime. We observe an increase of {approximately}200% in beam lifetime by operating at the betatron coupling resonance.

  3. BEAMS3D Neutral Beam Injection Model

    SciTech Connect

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  4. Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA

    SciTech Connect

    Machida, S.; Barlow, R.; Berg, J.S.; Bliss, N.; Buckley, R.K.; Clarke, J.A.; Craddock, M.K.; D'Arcy, R.; Edgecock, R.; Garland, J.M.; Giboudot, Y.; /Rutherford /Huddersfield U. /Brookhaven /Daresbury /Cockcroft Inst. Accel. Sci. Tech. /TRIUMF /British Columbia U., Vancouver, Dept. Phys. Astron. /University Coll. London /Manchester U. /Brunel U. /ASP, Melbourne

    2012-03-01

    In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a 'scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10?mm in radius over an electron momentum range of 12-18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.

  5. Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators

    SciTech Connect

    V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard

    2012-06-01

    Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

  6. Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA

    NASA Astrophysics Data System (ADS)

    Machida, S.; Barlow, R.; Berg, J. S.; Bliss, N.; Buckley, R. K.; Clarke, J. A.; Craddock, M. K.; D'Arcy, R.; Edgecock, R.; Garland, J. M.; Giboudot, Y.; Goudket, P.; Griffiths, S.; Hill, C.; Hill, S. F.; Hock, K. M.; Holder, D. J.; Ibison, M. G.; Jackson, F.; Jamison, S. P.; Johnstone, C.; Jones, J. K.; Jones, L. B.; Kalinin, A.; Keil, E.; Kelliher, D. J.; Kirkman, I. W.; Koscielniak, S.; Marinov, K.; Marks, N.; Martlew, B.; McIntosh, P. A.; McKenzie, J. W.; Méot, F.; Middleman, K. J.; Moss, A.; Muratori, B. D.; Orrett, J.; Owen, H. L.; Pasternak, J.; Peach, K. J.; Poole, M. W.; Rao, Y.-N.; Saveliev, Y.; Scott, D. J.; Sheehy, S. L.; Shepherd, B. J. A.; Smith, R.; Smith, S. L.; Trbojevic, D.; Tzenov, S.; Weston, T.; Wheelhouse, A.; Williams, P. H.; Wolski, A.; Yokoi, T.

    2012-03-01

    In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a `scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10mm in radius over an electron momentum range of 12-18MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.

  7. Patients' satisfaction and maintenance of fixed partial denture

    PubMed Central

    Geiballa, Ghada Hassan; Abubakr, Neamat Hassan; Ibrahim, Yahia Eltayib

    2016-01-01

    Objectives: The aims of this study were to evaluate patient satisfaction with fixed prosthesis following placement and to assess the oral health and oral hygiene practices awareness by survey questionnaire. Materials and Methods: One hundred and ninety-two questionnaires were filled by patients wearing fixed prosthesis; the questionnaire included the subjective perception of treatment with fixed prosthesis, patients' perception of clinical outcome, regarding esthetics, masticatory function, speech, and together patient's attitude toward oral hygiene measures. Results: Results showed that 84% of the patients were satisfied with their fixed prosthesis, while only 46.4% of patients were satisfied with the chewing ability. In concern, with esthetic outcome, 80% of patients showed that they were satisfied with the esthetic. The results showed that a high significantly number of patients did not use any form of interdental aids' to clean their fixed prosthesis (94%). The main reason for not using any dental aids' (91.1%) was a lack of post fixed prosthodontics instructions and not been informed by the dentist. Conclusion: High percentages of patients were satisfied with their fixed prosthesis. The most important finding of this study was that majority of patients showed a lack of knowledge regarding post fixed prosthodontics instructions and the significance of maintenance of fixed prosthesis using dental aids'. Of particular concern was the majority of dentists did not pay attention to the post treatment instructions concerning the maintenance of fixed prosthesis. PMID:27095906

  8. An expression of interest in a Super Fixed Target Beauty Facility (SFT) at the Superconducting Super Collider

    SciTech Connect

    Not Available

    1990-05-25

    The concept of a Super Fixed Target Beauty Facility (SFT) which uses a relatively low intensity 20 TeV proton beam as a generator of very high momenta B's is an exciting prospect which is very competitive with other B factory ideas. The yields of B's in such a facility are quite high (3 {times} 10{sup 10} {yields} 10{sup 11} B's per year). At this level of statistics, CP violation measurements will be possible in many modes. In addition, the fixed target configuration, because of the high momenta of the produced B's and the resulting long decay lengths, facilitates the detection and reconstruction of B's and offers unique opportunities for observation of the B decays. The limited solid angle coverage required for the fixed target spectrometer makes the cost of the facility much cheaper than other e{sup +}e{sup {minus}} or hadron collider options under consideration. The relatively low intensity 20 TeV beam (1 {yields} 2 {times} 10{sup 8} protons/second) needed for the SFT makes it possible to consider an extraction system which operates concurrently and in a non-interfering manner with the other collider experiments. One possible method for generating such a beam, crystal channeling, is discussed.

  9. Low Emittance Electron Beam Studies

    SciTech Connect

    Tikhoplav, Rodion

    2006-04-01

    We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*{sub 01} mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.

  10. Laser-Beam Separator

    NASA Technical Reports Server (NTRS)

    Mcdermid, I. S.

    1984-01-01

    Train of prisms and optical stop separate fundamental beam of laser from second and higher order harmonics of beam produced in certain crystals and by stimulated Raman scattering in gases and liquids.

  11. Electron Beam Freeform Fabrication

    NASA Video Gallery

    Electron Beam Freeform Fabrication (EBF3) is a process by which NASA hopes to build metal parts in zero gravity environments. It's a layer-additive process that uses an electron beam and a solid wi...

  12. Intra-beam scattering

    NASA Astrophysics Data System (ADS)

    Piwinski, A.

    Intra-beam scattering is analysed and the rise times or damping times of the beam dimensions are derived. The theoretical results are compared with experimental values obtained on the CERN AA and SPS machines.

  13. High energy beam lines

    NASA Astrophysics Data System (ADS)

    Marchetto, M.; Laxdal, R. E.

    2014-01-01

    The ISAC post accelerator comprises an RFQ, DTL and SC-linac. The high energy beam lines connect the linear accelerators as well as deliver the accelerated beams to two different experimental areas. The medium energy beam transport (MEBT) line connects the RFQ to the DTL. The high energy beam transport (HEBT) line connects the DTL to the ISAC-I experimental stations (DRAGON, TUDA-I, GPS). The DTL to superconducting beam (DSB) transport line connects the ISAC-I and ISAC-II linacs. The superconducting energy beam transport (SEBT) line connects the SC linac to the ISAC-II experimental station (TUDA-II, HERACLES, TIGRESS, EMMA and GPS). All these lines have the function of transporting and matching the beams to the downstream sections by manipulating the transverse and longitudinal phase space. They also contain diagnostic devices to measure the beam properties.

  14. PARTICLE BEAM TRACKING CIRCUIT

    DOEpatents

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  15. Electron beam focusing system

    SciTech Connect

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  16. Beam Dynamics for ARIA

    SciTech Connect

    Ekdahl, Carl August Jr.

    2014-10-14

    Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

  17. Drug discrimination under a concurrent fixed-ratio fixed-ratio schedule.

    PubMed Central

    McMillan, D E; Li, M

    1999-01-01

    Pigeons were trained to discriminate 5.0 mg/kg pentobarbital from saline under a two-key concurrent fixed-ratio 10 fixed-ratio 40 schedule of food presentation, in which the fixed-ratio component with the lower response requirement was programmed to reinforce responding on one key after drug administration (pentobarbital-biased key) and on the other key after saline administration (saline-biased key). After responding stabilized, pigeons averaged 98% of their responses on the pentobarbital-biased key during training sessions preceded by pentobarbital, and they averaged 90% of their responses on the saline-biased key during training sessions preceded by saline. In test sessions preceded by doses of pentobarbital, chlordiazepoxide, or ethanol, pigeons switched from responding on the saline-biased key at low doses to responding on the pentobarbital-biased key at higher doses (the dose-response curve was quantal). High doses of phencyclidine produced responding on both keys, whereas pigeons responded almost exclusively on the saline-biased key after all doses of methamphetamine. These and previous experiments using concurrent reinforcement schedules to study drug discrimination illustrate that the schedule of reinforcement is an important determinant of the shape of dose-effect curves in drug-discrimination experiments. PMID:10503298

  18. Fixed duration MDT in paucibacillary leprosy.

    PubMed

    Mathai, R; George, S; Jacob, M

    1991-06-01

    The World Health Organization (WHO) has recommended a fixed duration of multidrug therapy (MDT) for paucibacillary leprosy which is currently widely implemented in India. A clinico-pathological study was initiated in 1984 to assess the efficacy of this regimen. The clinical and histological responses of the patients to MDT were assessed at the end of 6 months, when their treatment was stopped, and at 2 1/2 years, when they were released from surveillance, and compared with the responses of a matched patient group to conventional dapsone (DDS) monotherapy during the same period. Of 28 patients who completed the MDT schedule, there was less than 60% improvement in 33% of them when treatment was stopped at the end of 6 months and in 20% of them at the end of 2 1/2 years. Of 26 patients receiving DDS monotherapy, 37% showed less than 60% improvement at the end of 6 months but only 8.8% had less than 60% improvement at 2 1/2 years. It is concluded that MDT for paucibacillary leprosy as recommended by WHO may not have a major advantage over DDS monotherapy, since about 20% of those patients on MDT continue to have evidence of active disease when discharged from surveillance. PMID:2071980

  19. Materials and techniques in fixed prosthodontics.

    PubMed

    Naylor, W P; Beatty, M W

    1992-07-01

    If we have learned anything from our experiences with all-ceramic systems such as Cerestore, Cerapearl, and even Dicor, it is that it takes years to uncover the strengths, weaknesses, and limitations of new materials and technologies. Manufacturers' initial claims for fit, strength, esthetics, biocompatibility, wear characteristics, and clinical performance should be viewed as preliminary until supported by independent laboratory and clinical studies. Laboratory testing alone may not provide sufficient insight into the relative strengths and weaknesses of products or assure comparable performance in the commercial dental laboratory or the ultimate testing arena, the oral environment. Moreover, the diversity of the new materials and techniques discussed demonstrates the breadth and depth of the technologic changes in dental biomaterials. The rate at which these dental products enter the marketplace and their sheer number alone are indeed staggering. Furthermore, these advances are not emerging from any single nation but from manufacturers all around the world (Japan, Germany, as well as the United States), indicating our international reliance on one another. Clearly, the decade of the 1990s is emerging as an exciting period in the development of biomaterials in comprehensive fixed prosthodontics and dentistry in general. PMID:1327885

  20. Seven lean years. [No quick fix available

    SciTech Connect

    Byron, C.

    1980-12-22

    The end of the cheap oil era is having a more profound impact than any other single issue or event since World War II, making the everything crisis a more-appropriate label than energy crisis. Warnings from OPEC that oil may rise to $60 per barrel will not have worldwide inventories as a moderating force because the Iran-Iraq war has reduced OPEC production to the point where oil companies are unwilling to draw down their stockpiles. The cartel's prices have merely exploited a worldwide increase in demand for oil that would have pushed prices up anyway. The social and economic havoc is straining the economies of developed countries and could bankrupt and destabilize much of the Third World. The search for non-OPEC oil sources and alternatives to oil prompted a global race to discover new reserves, exploit renewable fuel sources, and initiate conservation. With no quick fix available, a painful period is foreseen while people learn to husband natural resources. (DCK)

  1. Apparatus for fixed bed coal gasification

    DOEpatents

    Sadowski, Richard S.

    1992-01-01

    An apparatus for fixed-bed coal gasification is described in which coal such as caking coal is continuously pyrolyzed with clump formation inhibited, by combining the coal with a combustible gas and an oxidant, and then continually feeding the pyrolyzed coal under pressure and elevated temperature into the gasification region of a pressure vessel. The materials in the pressure vessel are allowed to react with the gasifying agents in order to allow the carbon contents of the pyrolyzed coal to be completely oxidized. The combustion of gas produced from the combination of coal pyrolysis and gasification involves combining a combustible gas coal and an oxidant in a pyrolysis chamber and heating the components to a temperature of at least 1600.degree. F. The products of coal pyrolysis are dispersed from the pyrolyzer directly into the high temperature gasification region of a pressure vessel. Steam and air needed for gasification are introduced in the pressure vessel and the materials exiting the pyrolyzer flow down through the pressure vessel by gravity with sufficient residence time to allow any carbon to form carbon monoxide. Gas produced from these reactions are then released from the pressure vessel and ash is disposed of.

  2. Difficulty in dislodging in vivo fixed radiostrontium.

    PubMed

    Sonawane, V R; Jagtap, V S; Pahuja, D N; Rajan, M G R; Samuel, A M

    2004-07-01

    Many trials based on the basic phenomena of isotopic dilution, adsorption, ion exchange, chelation, etc., have been attempted for the decorporation of radiostrontium, particularly Sr, after its entry in the in vivo system. We have recently demonstrated a non-isotopic carrier effect of some common calcium salts (calcium = 9 mg mL) to reduce the whole body retention of radiostrontium, if administered within 2 h after radiostrontium exposure and furthermore once daily, in rats, supplemented with calcium fortified diet. However, 25-30% of radiostrontium (compared to 50-60% in untreated animals) was still found to be retained in the animal even after 2 wk of treatment. Trial of some simple interventional measures, which would not adversely affect the animal metabolism, like pyrophosphate and magnesium sulfate, sodium citrate, chitin (a bio-absorbent), crown ether (a metal-chelator), and ammonium chloride, was therefore attempted to dislodge this remaining radiostrontium by switching over these animals to normal diet and subjecting them to different lines of treatment with these simple interventions through diet and drinking water separately for a further 4 wk. However, this remaining portion of radiostrontium is fixed in the bone and is difficult to dislodge. PMID:15194921

  3. Likelihoods for fixed rank nomination networks.

    PubMed

    Hoff, Peter; Fosdick, Bailey; Volfovsky, Alex; Stovel, Katherine

    2013-12-01

    Many studies that gather social network data use survey methods that lead to censored, missing, or otherwise incomplete information. For example, the popular fixed rank nomination (FRN) scheme, often used in studies of schools and businesses, asks study participants to nominate and rank at most a small number of contacts or friends, leaving the existence of other relations uncertain. However, most statistical models are formulated in terms of completely observed binary networks. Statistical analyses of FRN data with such models ignore the censored and ranked nature of the data and could potentially result in misleading statistical inference. To investigate this possibility, we compare Bayesian parameter estimates obtained from a likelihood for complete binary networks with those obtained from likelihoods that are derived from the FRN scheme, and therefore accommodate the ranked and censored nature of the data. We show analytically and via simulation that the binary likelihood can provide misleading inference, particularly for certain model parameters that relate network ties to characteristics of individuals and pairs of individuals. We also compare these different likelihoods in a data analysis of several adolescent social networks. For some of these networks, the parameter estimates from the binary and FRN likelihoods lead to different conclusions, indicating the importance of analyzing FRN data with a method that accounts for the FRN survey design. PMID:25110586

  4. How to fix a broken clock

    PubMed Central

    Schroeder, Analyne M.; Colwell, Christopher S.

    2013-01-01

    Fortunate are those who rise out of bed to greet the morning light well rested with the energy and enthusiasm to drive a productive day. Others however, depend on hypnotics for sleep and require stimulants to awaken lethargic bodies. Sleep/wake disruption is a common occurrence in healthy individuals throughout their lifespan and is also a comorbid condition to many diseases (neurodegenerative) and psychiatric disorders (depression and bipolar). There is growing concern that chronic disruption of the sleep/wake cycle contributes to more serious conditions including diabetes (type 2), cardiovascular disease and cancer. A poorly functioning circadian system resulting in misalignments in the timing of clocks throughout the body may be at the root of the problem for many people. In this article, we discuss environmental (light therapy) and lifestyle changes (scheduled meals, exercise and sleep) as interventions to help fix a broken clock. We also discuss the challenges and potential for future development of pharmacological treatments to manipulate this key biological system. PMID:24120229

  5. Galvanic gold plating for fixed dental prosthesis

    PubMed Central

    Ozcelik, Tuncer Burak; Yilmaz, Burak

    2013-01-01

    Metal ceramic partial fixed dental prostheses have been commonly used for the replacement of missing teeth for many years. Because of an increase in the price of gold, base metal alloys have been the choice of alloy for the fabrication of metal ceramic restorations in many dental clinics. Some major disadvantages of base metals are their corrosion and the dark coloration they may cause at the crown margins. This article describes a galvanic gold-plating technique, which is used to minimize corrosion and improve the esthetics of metal ceramic restorations fabricated with Cr-Co base metal alloys. This technique involves the deposition of a 6 μm to 8 μm 24 K gold layer directly onto the Cr-Co cast prosthesis framework. The technique improves metal surface properties, making them more biocompatible and usable, however, requires additional equipment and experienced laboratory technicians. Clinical studies should be performed to corroborate the long term success of this technique. PMID:24926220

  6. Beam injection into RHIC

    SciTech Connect

    Fischer, W.; Hahn, H.; MacKay, W.W.; Satogata, T.; Tsoupas, N.; Zhang, W.

    1997-07-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam.

  7. ATA beam director experiment

    SciTech Connect

    Lee, E.P.; Younger, F.C.; Cruz, G.E.; Nolting, E.

    1986-06-23

    This report describes beam director elements for an experiment at the Advanced Test Accelerator. The elements described include a vernier magnet for beam aiming, an achromat magnet, and an isolation system for the beam interface. These components are built at small scale for concept testing. (JDH)

  8. Laser beam color separator

    NASA Technical Reports Server (NTRS)

    Franke, J. M.

    1978-01-01

    Multiwavelength laser beam is separated into series of parallel color beams using prism and retroreflector. Setup is inexpensive and needs no critical adjustments. It can incorporate several prisms to increase dispersion and reduce overall size. Transmission grating can be used instead of prism with sacrifice in efficiency. Spatial filter can remove unwanted beams.

  9. Electron beam device

    DOEpatents

    Beckner, E.H.; Clauser, M.J.

    1975-08-12

    This patent pertains to an electron beam device in which a hollow target is symmetrically irradiated by a high energy, pulsed electron beam about its periphery and wherein the outer portion of the target has a thickness slightly greater than required to absorb the electron beam pulse energy. (auth)

  10. Halo formation from mismatched beam-beam interactions

    SciTech Connect

    Qiang, Ji

    2003-05-23

    In this paper, we report on the halo formation and emittance growth driven by a parametric resonance during mismatched beam-beam collisions. In the regime of the weak-strong beam-beam interaction, if two beams have the same machine tunes, on-axis head-on collisions between a mismatched strong beam and a weak beam will not cause the formation of halo. However, if the two beams collide with an initial offset, the beam-beam force from the mismatched strong beam can cause halo formation and emittance growth in the weak beam. Meanwhile, if two beams have different machine tunes, for opposite charged colliding beams, when the machine tune of the weak beam is smaller than that of strong beam, there is emittance growth in the weak beam. When the machine tune of the weak beam is larger than that of the strong beam, there is little emittance growth. In the regime of strong-strong beam-beam interaction, halo is formed in both beams even when the two beams collide head-on on the axis with equal machine tunes. This puts a strong requirement for a good beam match during the injection to colliders in order to avoid the emittance growth.

  11. In-situ X-ray diffraction system using sources and detectors at fixed angular positions

    DOEpatents

    Gibson, David M.; Gibson, Walter M.; Huang, Huapeng

    2007-06-26

    An x-ray diffraction technique for measuring a known characteristic of a sample of a material in an in-situ state. The technique includes using an x-ray source for emitting substantially divergent x-ray radiation--with a collimating optic disposed with respect to the fixed source for producing a substantially parallel beam of x-ray radiation by receiving and redirecting the divergent paths of the divergent x-ray radiation. A first x-ray detector collects radiation diffracted from the sample; wherein the source and detector are fixed, during operation thereof, in position relative to each other and in at least one dimension relative to the sample according to a-priori knowledge about the known characteristic of the sample. A second x-ray detector may be fixed relative to the first x-ray detector according to the a-priori knowledge about the known characteristic of the sample, especially in a phase monitoring embodiment of the present invention.

  12. Marginal adaptation analysis performed with en face optical coherence tomography in fixed partial dentures

    NASA Astrophysics Data System (ADS)

    Sinescu, Cosmin; Negrutiu, Meda Lavinia; Antonie, Sergiu; Dobre, George; Bradu, Adrian; Hughes, Michael; Rominu, Mihai; Podoleanu, Adrian Gh.

    2009-02-01

    Frameworks for fixed partial denture made out of dental alloys thought classic techniques currently involve many errors like marginal and internal gaps. The aim of this study is to present alternative technologies in making frameworks from dental alloys using selective laser sintering/ selective laser melting (SLS/ SLM) and to investigate the marginal adaptation of the fixed dental prostheses using the en face optical coherence tomography. These procedures imply the use of a scanning device PROBIS, SMART OPTICS with the help of 3D Dental Scanner software. For digitizing the 3D model we used the Dental Wings Kunde Software. The files obtained were sent to a SLS/ SLM machine, Hint-Els rapidPro, where the CoCr powder was sintered/melt by selectively consolidating successive layers of powder material on top of each other, using thermal energy supplied by a focused and computer controlled laser beam. Through this technique can be produced up to 80 pieces in only one step. A parallel between the classic casting technique and this new technology reveal the least has several advantages: fast finishing time, excellent marginal and internal fit, biocompatibility and superior chemical properties. SLS/ SLM proved to be a promising technology that may overcome the classic ones, because of the superior marginal fit of the fixed dental prostheses to the teeth.

  13. Advanced 30/20 GHz multiple-beam antennas for communications satellites

    NASA Technical Reports Server (NTRS)

    Myhre, R. W.

    1982-01-01

    Design concepts under development utilize two separate spacecraft antenna systems, one uplink at 30 GHz and the other a downlink at 20 GHz, where each antenna provides multiple fixed and scanning beams. Two contractors completed configuration trade-off studies and breadboarding of critical technology components, and are fabricating and testing proof-of-concept (POC) models to demonstrate the technology feasibility. Technology developments required for the proposed systems are presented, along with each contractor's progress to date. The technology development areas discussed include: (1) offset Cassegrain and shaped reflector systems for narrow beams with low sidelobes and wideangle off-axis scan; (2) diplexed beam-forming networks for dual polarization, low sidelobes, and fixed and scan-beam operation; (3) fast switching networks for scanning beams; and (4) fabrication of precision feed components and large offset reflectors.

  14. Beams for kaon research

    SciTech Connect

    Pile, P.H.

    1985-01-01

    A proposed 1-2 GeV/c kaon beam line for BNL, designed to deliver momentum analyzed negative kaon beams with intensities above 10/sup 6/ per spill, is discussed. The beam intensity is expected to be about an order of magnitude greater than presently available and it is expected to be a clean beam with no more than 1:1 (..pi../sup -/,..mu../sup -/,e/sup -/)/K/sup -/. The beam line will allow a detailed investigation of strangeness -2 systems as well as continued investigations of strangeness -1 systems.

  15. Neutral beam monitoring

    DOEpatents

    Fink, Joel H.

    1981-08-18

    Method and apparatus for monitoring characteristics of a high energy neutral beam. A neutral beam is generated by passing accelerated ions through a walled cell containing a low energy neutral gas, such that charge exchange neutralizes the high energy ion beam. The neutral beam is monitored by detecting the current flowing through the cell wall produced by low energy ions which drift to the wall after the charge exchange. By segmenting the wall into radial and longitudinal segments various beam conditions are further identified.

  16. BEAM CONTROL PROBE

    DOEpatents

    Chesterman, A.W.

    1959-03-17

    A probe is described for intercepting a desired portion of a beam of charged particles and for indicating the spatial disposition of the beam. The disclosed probe assembly includes a pair of pivotally mounted vanes moveable into a single plane with adjacent edges joining and a calibrated mechanical arrangement for pivoting the vancs apart. When the probe is disposed in the path of a charged particle beam, the vanes may be adjusted according to the beam current received in each vane to ascertain the dimension of the beam.

  17. Low-Z polymer sample supports for fixed-target serial femtosecond X-ray crystallography

    SciTech Connect

    Feld, Geoffrey K.; Heymann, Michael; Benner, W. Henry; Pardini, Tommaso; Tsai, Ching -Ju; Boutet, Sebastien; Coleman, Matthew A.; Hunter, Mark S.; Li, Xiaodan; Messerschmidt, Marc; Opathalage, Achini; Pedrini, Bill; Williams, Garth J.; Krantz, Bryan A.; Fraden, Seth; Hau-Riege, Stefan; Evans, James E.; Segelke, Brent W.; Frank, Matthias

    2015-06-27

    X-ray free-electron lasers (XFELs) offer a new avenue to the structural probing of complex materials, including biomolecules. Delivery of precious sample to the XFEL beam is a key consideration, as the sample of interest must be serially replaced after each destructive pulse. The fixed-target approach to sample delivery involves depositing samples on a thin-film support and subsequent serial introduction via a translating stage. Some classes of biological materials, including two-dimensional protein crystals, must be introduced on fixed-target supports, as they require a flat surface to prevent sample wrinkling. A series of wafer and transmission electron microscopy (TEM)-style grid supports constructed of low-Z plastic have been custom-designed and produced. Aluminium TEM grid holders were engineered, capable of delivering up to 20 different conventional or plastic TEM grids using fixed-target stages available at the Linac Coherent Light Source (LCLS). As proof-of-principle, X-ray diffraction has been demonstrated from two-dimensional crystals of bacteriorhodopsin and three-dimensional crystals of anthrax toxin protective antigen mounted on these supports at the LCLS. In conclusion, the benefits and limitations of these low-Z fixed-target supports are discussed; it is the authors' belief that they represent a viable and efficient alternative to previously reported fixed-target supports for conducting diffraction studies with XFELs.

  18. Fixed charge in the cell membrane

    PubMed Central

    Elul, R.

    1967-01-01

    1. Focal electric field was generated by passing a current of 5 × 10-7 to 1 × 10-5 A from a micropipette into the culture medium. Movement of cells at a distance of 5-50 μ from the electrode tip was observed. In case of cells embedded in the culture only local deformation of the membrane was observed. 2. The cell species explored included neurones, glia, muscle fibres, connective cells, malignant cells and erythrocytes. All cells responded in a similar manner to the electric field, and the current required was in the same range. 3. Cells were attracted to a positive micropipette and repelled from a negative one: the only exception was observed in certain malignant cells which moved in the opposite direction. 4. Movement and membrane deformation could be obtained with electrodes filled with various concentrated and isotonic solutions. The composition of the culture medium also had no qualitative influence on these effects. 5. Metabolic poisons or rupture of the cell membrane had no effect on the movement. Isolated membrane fragments showed movement similar to that of intact cells. 6. The possibility of artifacts due to proximity of the focal electrode is considered. It is shown that electro-osmosis cannot account for the present observations. Some other artifacts are also excluded. 7. It is proposed that the most satisfactory way to account for the present observations is by a membrane carrying negative fixed charge of the order of 2·5 × 103 e.s.u./cm2. Some physiological consequences of presence of negative charge in the membrane are briefly discussed. ImagesFig. 1Fig. 2Fig. 3 PMID:6040152

  19. Auxins upregulate nif and fix genes.

    PubMed

    Bianco, Carmen; Defez, Roberto

    2010-10-01

    In a recent publication we analyzed the global effects triggered by IAA overproduction in S. meliloti RD64 under free-living conditions by comparing the gene expression pattern of wild type 1021 with that of RD64 and 1021 treated with IAA and other four chemically or functionally related molecules. Among the genes differentially expressed in RD64 and IAA-treated 1021 cells we found two genes of pho operon, phoT and phoC. Based on this finding we examined the mechanisms for mineral P solubilization in RD64 and the potential ability of this strain to improve Medicago growth under P-starved conditions. Here, we further analyze the expression profiles obtained in microarray analysis and evaluate the specificity and the extent of overlap between all treatments. Venn diagrams indicated that IAA- and 2,4-D-regulated genes were closely related. Furthermore, most differentially expressed genes from pSymA were induced in 1021 cells treated with 2,4-D, ICA, IND and Trp as compared to the untreated 1021 cells. RT-PCR analysis was employed to analyze the differential expression patterns of nitrogen fixation genes under free-living and symbiotic conditions. Under symbiotic condition, the relative expression levels of nif and fix genes were significantly induced in Mt- RD64 plants and in Mt-1021 plants treated with IAA and 2,4-D whereas they were unchanged or repressed in Mt-1021 plants treated with the other selected compounds when compared to the untreated Mt-1021 plants. PMID:20930554

  20. Aeroelasticity Benchmark Assessment: Subsonic Fixed Wing Program

    NASA Technical Reports Server (NTRS)

    Florance, Jennifer P.; Chwalowski, Pawel; Wieseman, Carol D.

    2010-01-01

    Aeroelasticity Branch will examine other experimental efforts within the Subsonic Fixed Wing (SFW) program (such as testing of the NASA Common Research Model (CRM)) and other NASA programs and assess aeroelasticity issues and research topics.

  1. Shifted nondiffractive Bessel beams

    NASA Astrophysics Data System (ADS)

    Kovalev, Alexey A.; Kotlyar, Victor V.; Porfirev, Alexey A.

    2015-05-01

    Nondiffractive Bessel beams are well known to have infinite energy and infinite orbital angular momentum (OAM). However, when normalized to unity of energy, their OAM is finite. In this work, we derive an analytical relationship for calculating the normalized OAM of the superposition of off-axis Bessel beams characterized by the same topological charge. We show that if the constituent beams of the superposition have real-valued weight coefficients, the total OAM of the superposition of the Bessel beams equals that of an individual nonshifted Bessel beam. This property enables generating nondiffractive beams with different intensity distributions but identical OAM. The superposition of a set of identical Bessel beams centered on an arbitrary-radius circle is shown to be equivalent to an individual constituent Bessel beam put in the circle center. As a result of a complex shift of the Bessel beam, the transverse intensity distribution and OAM of the beam are also shown to change. We show that, in the superposition of two or more complex-shifted Bessel beams, the OAM may remain unchanged, while the intensity distribution is changed. Numerical simulation is in good agreement with theory.

  2. Dynamics of beam halo in mismatched beams

    SciTech Connect

    Wangler, T.P.; Garnett, R.W.; Gray, E.R.; Ryne, R.D.; Wang, T.S.

    1996-09-01

    High-power proton linacs for nuclear materials transmutation and production, and new accelerator-driven neutron spallation sources must be designed to control beam-halo formation, which leads to beam loss. The study of particle-core models is leading to a better understanding of the causes and characteristics of beam halo produced by space-charge forces in rms mismatched beams. Detailed studies of the models have resulted in predictions of the dependence of the maximum amplitude of halo particles on a mismatch parameter and on the space-charge tune-depression ratio. Scaling formulas have been derived which will provide guidance for choosing the aperture radius to contain the halo without loss.

  3. Conditions for reliable time-resolved dosimetry of electronic portal imaging devices for fixed-gantry IMRT and VMAT

    SciTech Connect

    Yeo, Inhwan Jason; Patyal, Baldev; Mandapaka, Anant; Jung, Jae Won; Yi, Byong Yong; Kim, Jong Oh

    2013-07-15

    Purpose: The continuous scanning mode of electronic portal imaging devices (EPID) that offers time-resolved information has been newly explored for verifying dynamic radiation deliveries. This study seeks to determine operating conditions (dose rate stability and time resolution) under which that mode can be used accurately for the time-resolved dosimetry of intensity-modulated radiation therapy (IMRT) beams.Methods: The authors have designed the following test beams with variable beam holdoffs and dose rate regulations: a 10 Multiplication-Sign 10 cm open beam to serve as a reference beam; a sliding window (SW) beam utilizing the motion of a pair of multileaf collimator (MLC) leaves outside the 10 Multiplication-Sign 10 cm jaw; a step and shoot (SS) beam to move the pair in step; a volumetric modulated arc therapy (VMAT) beam. The beams were designed in such a way that they all produce the same open beam output of 10 Multiplication-Sign 10 cm. Time-resolved ion chamber measurements at isocenter and time-resolved and integrating EPID measurements were performed for all beams. The time-resolved EPID measurements were evaluated through comparison with the ion chamber and integrating EPID measurements, as the latter are accepted procedures. For two-dimensional, time-resolved evaluation, a VMAT beam with an infield MLC travel was designed. Time-resolved EPID measurements and Monte Carlo calculations of such EPID dose images for this beam were performed and intercompared.Results: For IMRT beams (SW and SS), the authors found disagreement greater than 2%, caused by frame missing of the time-resolved mode. However, frame missing disappeared, yielding agreement better than 2%, when the dose rate of irradiation (and thus the frame acquisition rates) reached a stable and planned rate as the dose of irradiation was raised past certain thresholds (a minimum 12 s of irradiation per shoot used for SS IMRT). For VMAT, the authors found that dose rate does not affect the frame

  4. Conditions for reliable time-resolved dosimetry of electronic portal imaging devices for fixed-gantry IMRT and VMAT

    PubMed Central

    Yeo, Inhwan Jason; Jung, Jae Won; Patyal, Baldev; Mandapaka, Anant; Yong Yi, Byong; Oh Kim, Jong

    2013-01-01

    Purpose: The continuous scanning mode of electronic portal imaging devices (EPID) that offers time-resolved information has been newly explored for verifying dynamic radiation deliveries. This study seeks to determine operating conditions (dose rate stability and time resolution) under which that mode can be used accurately for the time-resolved dosimetry of intensity-modulated radiation therapy (IMRT) beams. Methods: The authors have designed the following test beams with variable beam holdoffs and dose rate regulations: a 10 × 10 cm open beam to serve as a reference beam; a sliding window (SW) beam utilizing the motion of a pair of multileaf collimator (MLC) leaves outside the 10 × 10 cm jaw; a step and shoot (SS) beam to move the pair in step; a volumetric modulated arc therapy (VMAT) beam. The beams were designed in such a way that they all produce the same open beam output of 10 × 10 cm. Time-resolved ion chamber measurements at isocenter and time-resolved and integrating EPID measurements were performed for all beams. The time-resolved EPID measurements were evaluated through comparison with the ion chamber and integrating EPID measurements, as the latter are accepted procedures. For two-dimensional, time-resolved evaluation, a VMAT beam with an infield MLC travel was designed. Time-resolved EPID measurements and Monte Carlo calculations of such EPID dose images for this beam were performed and intercompared. Results: For IMRT beams (SW and SS), the authors found disagreement greater than 2%, caused by frame missing of the time-resolved mode. However, frame missing disappeared, yielding agreement better than 2%, when the dose rate of irradiation (and thus the frame acquisition rates) reached a stable and planned rate as the dose of irradiation was raised past certain thresholds (a minimum 12 s of irradiation per shoot used for SS IMRT). For VMAT, the authors found that dose rate does not affect the frame acquisition rate, thereby causing no frame missing

  5. Tunable cavity resonator including a plurality of MEMS beams

    SciTech Connect

    Peroulis, Dimitrios; Fruehling, Adam; Small, Joshua Azariah; Liu, Xiaoguang; Irshad, Wasim; Arif, Muhammad Shoaib

    2015-10-20

    A tunable cavity resonator includes a substrate, a cap structure, and a tuning assembly. The cap structure extends from the substrate, and at least one of the substrate and the cap structure defines a resonator cavity. The tuning assembly is positioned at least partially within the resonator cavity. The tuning assembly includes a plurality of fixed-fixed MEMS beams configured for controllable movement relative to the substrate between an activated position and a deactivated position in order to tune a resonant frequency of the tunable cavity resonator.

  6. Human cell lines: A promising alternative for recombinant FIX production.

    PubMed

    de Sousa Bomfim, Aline; Cristina Corrêa de Freitas, Marcela; Picanço-Castro, Virgínia; de Abreu Soares Neto, Mário; Swiech, Kamilla; Tadeu Covas, Dimas; Maria de Sousa Russo, Elisa

    2016-05-01

    Factor IX (FIX) is a vitamin K-dependent protein, and it has become a valuable pharmaceutical in the Hemophilia B treatment. We evaluated the potential of recombinant human FIX (rhFIX) expression in 293T and SK-Hep-1 human cell lines. SK-Hep-1-FIX cells produced higher levels of biologically active protein. The growth profile of 293T-FIX cells was not influenced by lentiviral integration number into the cellular genome. SK-Hep-1-FIX cells showed a significantly lower growth rate than SK-Hep-1 cells. γ-carboxylation process is significant to FIX biological activity, thus we performed a expression analysis of genes involved in this process. The 293T gene expression suggests that this cell line could efficiently carboxylate FIX, however only 28% of the total secreted protein is active. SK-Hep-1 cells did not express high amounts of VKORC1 and carboxylase, but this cell line secreted large amounts of active protein. Enrichment of culture medium with Ca(+2) and Mg(+2) ions did not affect positively rhFIX expression in SK-Hep-1 cells. In 293T cells, the addition of 0.5 mM Ca(+2) and 1 mM Mg(+2) resulted in higher rhFIX concentration. SK-Hep-1 cell line proved to be very effective in rhFIX production, and it can be used as a novel biotechnological platform for the production of recombinant proteins. PMID:26802680

  7. Point Scanning Microscope with Adaptive Illumination Beam Intensity

    NASA Astrophysics Data System (ADS)

    Das, Abhijit; Boruah, B. R.

    2011-10-01

    In this paper we describe a point scanning optical microscope where the illumination beam can be programmably controlled in real time using a liquid crystal spatial light modulator (LCSLM). With an appropriate pattern displayed on the LCSLM, the device can be made to act as a binary diffraction hologram. In the proposed microscope the illumination beam is in fact the +1 order beam diffracted from the binary hologram. By displaying a sequence of binary holograms it is possible to make a beam scanning, similar to a conventional scanning microscope. Here we use a computer generated holography technique to compute the binary holograms which facilitate complete control of the amplitude and phase profile of the illumination beam. In a number of microscopy applications using reflected light, the reflectivity of the sample plane may differ from region to region. Therefore if a single illumination beam intensity is used for the whole sample plane, then the regions with less reflectivity will be imaged with poor signal to noise ratio. In our proposed microscope the sample plane is first imaged to determine the regions of weak reflectivity. Holograms are then computed to make the illumination beam adapt to the reflectivity variations in the given sample plane. The image obtained with the modified set of holograms have superior signal to noise ratio all over, relative to a conventional point scanning microscope with a fixed intensity illumination beam. In this paper we present some preliminary results using the proposed setup.

  8. Dynamic bowtie for fan-beam CT.

    PubMed

    Liu, Fenglin; Wang, Ge; Cong, Wenxiang; Hsieh, Scott S; Pelc, Norbert J

    2013-01-01

    A bowtie is a filter used to shape an x-ray beam and equalize its flux reaching different detector channels. For development of spectral CT with energy discriminating photon-counting (EDPC) detectors, here we propose and evaluate a dynamic bowtie for performance optimization based on a patient model or a scout scan. With a mechanical rotation of a dynamic bowtie and an adaptive adjustment of an x-ray source flux, an x-ray beam intensity profile can be modulated. First, a mathematical model for dynamic bowtie filtering is established for an elliptical section in fan-beam geometry, and the contour of the optimal bowtie is derived. Then, numerical simulation is performed to compare the performance of the dynamic bowtie in the cases of an ideal phantom and a realistic cross-section relative to the counterparts without any bowtie and with a fixed bowtie respectively. Our dynamic bowtie can equalize the expected numbers of photons in the case of an ideal phantom. In practical cases, our dynamic bowtie can effectively reduce the dynamic range of detected signals inside the field of view. Although our design is optimized for an elliptical phantom, the resultant dynamic bowtie can be applied to a real fan-beam scan if the underlying cross-section can be approximated as an ellipse. Furthermore, our design methodology can be applied to specify an optimized dynamic bowtie for any cross-section of a patient, preferably using rapid prototyping technology. PMID:24191994

  9. Dynamics of a flexible extendible beam

    NASA Astrophysics Data System (ADS)

    Stylianou, Marinos Costa

    Axially moving materials arise in problems associated with spacecraft antennas, pipes conveying fluid, and telescopic robotic manipulators. Hamilton's principle is used to derive the governing differential equation of motion and system invariant properties of a flexible extendible beam (FEB) protruding from a rigid wall with prescribed extrusion profile. Numerical solutions are obtained using finite element analysis in which the number of elements is fixed while the sizes of the elements change with time. To this end, a variable domain beam finite element whose size is a prescribed function of time is formulated. The accuracy of this variable domain beam element is demonstrated through the time integration of equations of motion using various extrusion profiles. Additional verification is performed by the evaluation of the system's invariant quantities, comparison with special analytical solution, and the dynamic stability analysis of pipes conveying fluid. The effects of wall flexibility, tip mass, and high frequency axial motion perturbations to the transverse response of the FEB are also examined. The versatility and power of the finite element formulation is demonstrated in a simulation of an extruding FEB which carries a tip mass and protrudes from a flexible envelope beam which imparts three dimensional rigid-body rotations to the system.

  10. Photogrammetric Measurements in Fixed Wing Uav Imagery

    NASA Astrophysics Data System (ADS)

    Gülch, E.

    2012-07-01

    Several flights have been undertaken with PAMS (Photogrammetric Aerial Mapping System) by Germap, Germany, which is briefly introduced. This system is based on the SmartPlane fixed-wing UAV and a CANON IXUS camera system. The plane is equipped with GPS and has an infrared sensor system to estimate attitude values. A software has been developed to link the PAMS output to a standard photogrammetric processing chain built on Trimble INPHO. The linking of the image files and image IDs and the handling of different cases with partly corrupted output have to be solved to generate an INPHO project file. Based on this project file the software packages MATCH-AT, MATCH-T DSM, OrthoMaster and OrthoVista for digital aerial triangulation, DTM/DSM generation and finally digital orthomosaik generation are applied. The focus has been on investigations on how to adapt the "usual" parameters for the digital aerial triangulation and other software to the UAV flight conditions, which are showing high overlaps, large kappa angles and a certain image blur in case of turbulences. It was found, that the selected parameter setup shows a quite stable behaviour and can be applied to other flights. A comparison is made to results from other open source multi-ray matching software to handle the issue of the described flight conditions. Flights over the same area at different times have been compared to each other. The major objective was here to see, on how far differences occur relative to each other, without having access to ground control data, which would have a potential for applications with low requirements on the absolute accuracy. The results show, that there are influences of weather and illumination visible. The "unusual" flight pattern, which shows big time differences for neighbouring strips has an influence on the AT and DTM/DSM generation. The results obtained so far do indicate problems in the stability of the camera calibration. This clearly requests a usage of GCPs for all

  11. COLLIDING CRYSTALLINE BEAMS.

    SciTech Connect

    WEI, J.

    1998-06-26

    The understanding of crystalline beams has advanced to the point where one can now, with reasonable confidence, undertake an analysis of the luminosity of colliding crystalline beams. Such a study is reported here. It is necessary to observe the criteria, previously stated, for the creation and stability of crystalline beams. This requires, firstly, the proper design of a lattice. Secondly, a crystal must be formed, and this can usually be done at various densities. Thirdly, the crystals in a colliding-beam machine are brought into collision. We study all of these processes using the molecular dynamics (MD) method. The work parallels what was done previously, but the new part is to study the crystal-crystal interaction in collision. We initially study the zero-temperature situation. If the beam-beam force (or equivalent tune shift) is too large then overlapping crystals can not be created (rather two spatially separated crystals are formed). However, if the beam-beam force is less than but comparable to that of the space-charge forces between the particles, we find that overlapping crystals can be formed and the beam-beam tune shift can be of the order of unity. Operating at low but non-zero temperature can increase the luminosity by several orders of magnitude over that of a usual collider. The construction of an appropriate lattice, and the development of adequately strong cooling, although theoretically achievable, is a challenge in practice.

  12. Colliding Crystalline Beams

    SciTech Connect

    Wei, Jie; Sessler, A.M.

    1998-06-01

    The understanding of crystalline beams has advanced to the point where one can now, with reasonable confidence, undertake an analysis of the luminosity of colliding crystalline beams. Such a study is reported here. It is necessary to observe the criteria, previously stated, for the creation and stability of crystalline beams. This requires, firstly, the proper design of a lattice. Secondly, a crystal must be formed, and this can usually be done at various densities. Thirdly, the crystals in a colliding-beam machine are brought into collision. We study all of these processes using the molecular dynamics (MD) method. The work parallels what was done previously, but the new part is to study the crystal-crystal interaction in collision. We initially study the zero-temperature situation. If the beam-beam force (or equivalent tune shift) is too large then over-lapping crystals can not be created (rather two spatially separated crystals are formed). However, if the beam-beam force is less than but comparable to that of the space-charge forces between the particles, we find that overlapping crystals can be formed and the beam-beam tune shift can be of the order of unity. Operating at low but non-zero temperature can increase the luminosity by several orders of magnitude over that of a usual collider. The construction of an appropriate lattice, and the development of adequately strong coding, although theoretically achievable, is a challenge in practice.

  13. 46 CFR 184.410 - Electronic position fixing devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Electronic position fixing devices. 184.410 Section 184.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER... Electronic position fixing devices. A vessel on an oceans route must be equipped with an electronic...

  14. 46 CFR 184.410 - Electronic position fixing devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Electronic position fixing devices. 184.410 Section 184.410 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER... Electronic position fixing devices. A vessel on an oceans route must be equipped with an electronic...

  15. Ingestion of a Fixed Partial Denture During General Anesthesia

    PubMed Central

    Neustein, Steve; Beicke, Mark

    2007-01-01

    Dental trauma during anesthesia is a common occurrence. Many patients have had extensive dental work, which is more fragile than the natural dentition. This work may include crowns, fixed partial dentures (bridges), and porcelain veneers. We report for the first time, a case in which a fixed partial denture became dislodged and was ingested, and was recovered postoperatively with endoscopy. PMID:17579503

  16. 5 CFR 532.105 - Pay-fixing authority.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Pay-fixing authority. 532.105 Section 532.105 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PREVAILING RATE SYSTEMS General Provisions § 532.105 Pay-fixing authority. The head of each agency shall...

  17. 5 CFR 532.105 - Pay-fixing authority.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Pay-fixing authority. 532.105 Section 532.105 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PREVAILING RATE SYSTEMS General Provisions § 532.105 Pay-fixing authority. The head of each agency shall...

  18. 48 CFR 216.403 - Fixed-price incentive contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Fixed-price incentive contracts. 216.403 Section 216.403 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS... Contracts 216.403 Fixed-price incentive contracts....

  19. 48 CFR 846.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Fixed-price supply contracts. 846.302 Section 846.302 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 846.302 Fixed-price supply contracts....

  20. 48 CFR 546.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Fixed-price supply contracts. 546.302 Section 546.302 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.302 Fixed-price supply contracts....

  1. 40 CFR 63.1042 - Standards-Separator fixed roof.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Standards-Separator fixed roof. 63...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1042 Standards—Separator fixed roof. (a) This section applies to owners and operators subject to this subpart...

  2. 40 CFR 63.902 - Standards-Tank fixed roof.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fixed roof. This section does not apply to a fixed-roof tank that is also equipped with an internal... tank internal pressure in accordance with the tank design specifications. The device shall be designed... position whenever the tank internal pressure is within the internal pressure operating range determined...

  3. 29 CFR 1918.24 - Fixed and portable ladders.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Fixed and portable ladders. 1918.24 Section 1918.24 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Gangways and Other Means of Access § 1918.24 Fixed and portable ladders. (a)...

  4. 29 CFR 1918.24 - Fixed and portable ladders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Fixed and portable ladders. 1918.24 Section 1918.24 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Gangways and Other Means of Access § 1918.24 Fixed and portable ladders. (a)...

  5. 49 CFR 1562.25 - Fixed base operator requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Fixed base operator requirements. 1562.25 Section 1562.25 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY... Operations § 1562.25 Fixed base operator requirements. (a) Security program. Each FBO must adopt and...

  6. Floating-to-Fixed-Point Conversion for Digital Signal Processors

    NASA Astrophysics Data System (ADS)

    Menard, Daniel; Chillet, Daniel; Sentieys, Olivier

    2006-12-01

    Digital signal processing applications are specified with floating-point data types but they are usually implemented in embedded systems with fixed-point arithmetic to minimise cost and power consumption. Thus, methodologies which establish automatically the fixed-point specification are required to reduce the application time-to-market. In this paper, a new methodology for the floating-to-fixed point conversion is proposed for software implementations. The aim of our approach is to determine the fixed-point specification which minimises the code execution time for a given accuracy constraint. Compared to previous methodologies, our approach takes into account the DSP architecture to optimise the fixed-point formats and the floating-to-fixed-point conversion process is coupled with the code generation process. The fixed-point data types and the position of the scaling operations are optimised to reduce the code execution time. To evaluate the fixed-point computation accuracy, an analytical approach is used to reduce the optimisation time compared to the existing methods based on simulation. The methodology stages are described and several experiment results are presented to underline the efficiency of this approach.

  7. 29 CFR 1910.160 - Fixed extinguishing systems, general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... flooding systems by means of an approved fire detection device installed and interconnected with a pre... 29 Labor 5 2014-07-01 2014-07-01 false Fixed extinguishing systems, general. 1910.160 Section 1910... § 1910.160 Fixed extinguishing systems, general. (a) Scope and application. (1) This section applies...

  8. 29 CFR 1910.160 - Fixed extinguishing systems, general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... flooding systems by means of an approved fire detection device installed and interconnected with a pre... 29 Labor 5 2011-07-01 2011-07-01 false Fixed extinguishing systems, general. 1910.160 Section 1910... § 1910.160 Fixed extinguishing systems, general. (a) Scope and application. (1) This section applies...

  9. 29 CFR 1910.160 - Fixed extinguishing systems, general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... flooding systems by means of an approved fire detection device installed and interconnected with a pre... 29 Labor 5 2013-07-01 2013-07-01 false Fixed extinguishing systems, general. 1910.160 Section 1910... § 1910.160 Fixed extinguishing systems, general. (a) Scope and application. (1) This section applies...

  10. 48 CFR 846.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Fixed-price supply contracts. 846.302 Section 846.302 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 846.302 Fixed-price supply contracts....

  11. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202...

  12. 48 CFR 846.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Fixed-price supply contracts. 846.302 Section 846.302 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 846.302 Fixed-price supply contracts....

  13. 48 CFR 546.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Fixed-price supply contracts. 546.302 Section 546.302 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.302 Fixed-price supply contracts....

  14. 48 CFR 846.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Fixed-price supply contracts. 846.302 Section 846.302 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 846.302 Fixed-price supply contracts....

  15. 48 CFR 546.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Fixed-price supply contracts. 546.302 Section 546.302 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.302 Fixed-price supply contracts....

  16. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202...

  17. 48 CFR 846.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Fixed-price supply contracts. 846.302 Section 846.302 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 846.302 Fixed-price supply contracts....

  18. 48 CFR 546.302 - Fixed-price supply contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Fixed-price supply contracts. 546.302 Section 546.302 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION CONTRACT MANAGEMENT QUALITY ASSURANCE Contract Clauses 546.302 Fixed-price supply contracts....

  19. 30 CFR 75.360 - Preshift examination at fixed intervals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Preshift examination at fixed intervals. 75.360 Section 75.360 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.360 Preshift examination at fixed intervals. (a)(1) Except...

  20. 29 CFR 1910.162 - Fixed extinguishing systems, gaseous agent.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Fixed extinguishing systems, gaseous agent. 1910.162 Section 1910.162 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Fire Protection Fixed...

  1. 46 CFR 28.320 - Fixed gas fire extinguishing systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Stage of Construction on or After or Which Undergo a Major Conversion Completed on or After September 15...) or more in length must be fitted with a fixed gas fire extinguishing system in the following enclosed...) System types and alternatives. (1) A pre-engineered fixed gas fire extinguishing system may be...

  2. 46 CFR 28.320 - Fixed gas fire extinguishing systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Stage of Construction on or After or Which Undergo a Major Conversion Completed on or After September 15...) or more in length must be fitted with a fixed gas fire extinguishing system in the following enclosed...) System types and alternatives. (1) A pre-engineered fixed gas fire extinguishing system may be...

  3. 46 CFR 28.320 - Fixed gas fire extinguishing systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Stage of Construction on or After or Which Undergo a Major Conversion Completed on or After September 15...) or more in length must be fitted with a fixed gas fire extinguishing system in the following enclosed...) System types and alternatives. (1) A pre-engineered fixed gas fire extinguishing system may be...

  4. 46 CFR 28.320 - Fixed gas fire extinguishing systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Stage of Construction on or After or Which Undergo a Major Conversion Completed on or After September 15...) or more in length must be fitted with a fixed gas fire extinguishing system in the following enclosed...) System types and alternatives. (1) A pre-engineered fixed gas fire extinguishing system may be...

  5. 46 CFR 28.320 - Fixed gas fire extinguishing systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Stage of Construction on or After or Which Undergo a Major Conversion Completed on or After September 15...) or more in length must be fitted with a fixed gas fire extinguishing system in the following enclosed...) System types and alternatives. (1) A pre-engineered fixed gas fire extinguishing system may be...

  6. Asset Prices and Trading Volume under Fixed Transactions Costs.

    ERIC Educational Resources Information Center

    Lo, Andrew W.; Mamaysky, Harry; Wang, Jiang

    2004-01-01

    We propose a dynamic equilibrium model of asset prices and trading volume when agents face fixed transactions costs. We show that even small fixed costs can give rise to large "no-trade" regions for each agent's optimal trading policy. The inability to trade more frequently reduces the agents' asset demand and in equilibrium gives rise to a…

  7. 49 CFR 218.109 - Hand-operated fixed derails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Hand-operated fixed derails. 218.109 Section 218.109 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Derails § 218.109 Hand-operated fixed derails. (a)(1) Each railroad shall adopt and comply with...

  8. 49 CFR 218.109 - Hand-operated fixed derails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Hand-operated fixed derails. 218.109 Section 218.109 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Derails § 218.109 Hand-operated fixed derails. (a)(1) Each railroad shall adopt and comply with...

  9. 49 CFR 218.109 - Hand-operated fixed derails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Hand-operated fixed derails. 218.109 Section 218.109 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Derails § 218.109 Hand-operated fixed derails. (a)(1) Each railroad shall adopt and comply with...

  10. 49 CFR 218.109 - Hand-operated fixed derails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Hand-operated fixed derails. 218.109 Section 218.109 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Derails § 218.109 Hand-operated fixed derails. (a)(1) Each railroad shall adopt and comply with...

  11. 49 CFR 218.109 - Hand-operated fixed derails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Hand-operated fixed derails. 218.109 Section 218.109 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Derails § 218.109 Hand-operated fixed derails. (a)(1) Each railroad shall adopt and comply with...

  12. 47 CFR 101.815 - Stations at temporary fixed locations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Stations at temporary fixed locations. 101.815 Section 101.815 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.815 Stations at...

  13. 47 CFR 101.815 - Stations at temporary fixed locations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Stations at temporary fixed locations. 101.815 Section 101.815 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.815 Stations at...

  14. 46 CFR 169.565 - Fixed carbon dioxide system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565... Lifesaving and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space protected must be equal to the gross volume...

  15. 46 CFR 169.565 - Fixed carbon dioxide system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565... Lifesaving and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space protected must be equal to the gross volume...

  16. 46 CFR 169.565 - Fixed carbon dioxide system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565... Lifesaving and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space protected must be equal to the gross volume...

  17. 46 CFR 169.565 - Fixed carbon dioxide system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565... Lifesaving and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space protected must be equal to the gross volume...

  18. 46 CFR 169.565 - Fixed carbon dioxide system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565... Lifesaving and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space protected must be equal to the gross volume...

  19. 12 CFR 619.9180 - Fixed interest spread.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Fixed interest spread. 619.9180 Section 619.9180 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9180 Fixed interest spread. A percentage to be added to the cost of money to the bank or association as the means...

  20. 34 CFR 76.566 - Fixed costs-restricted rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Fixed costs-restricted rate. 76.566 Section 76.566 Education Office of the Secretary, Department of Education STATE-ADMINISTERED PROGRAMS What Conditions Must Be Met by the State and Its Subgrantees? Indirect Cost Rates § 76.566 Fixed costs—restricted rate....

  1. 46 CFR 169.564 - Fixed extinguishing system, general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Fixed extinguishing system, general. 169.564 Section 169.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Firefighting Equipment § 169.564 Fixed extinguishing...

  2. 46 CFR 169.564 - Fixed extinguishing system, general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Fixed extinguishing system, general. 169.564 Section 169.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Firefighting Equipment § 169.564 Fixed extinguishing...

  3. 46 CFR 169.564 - Fixed extinguishing system, general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Fixed extinguishing system, general. 169.564 Section 169.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Firefighting Equipment § 169.564 Fixed extinguishing...

  4. 46 CFR 169.564 - Fixed extinguishing system, general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Fixed extinguishing system, general. 169.564 Section 169.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Firefighting Equipment § 169.564 Fixed extinguishing...

  5. 46 CFR 169.564 - Fixed extinguishing system, general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Fixed extinguishing system, general. 169.564 Section 169.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Firefighting Equipment § 169.564 Fixed extinguishing...

  6. 47 CFR 15.307 - Coordination with fixed microwave service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Coordination with fixed microwave service. 15.307 Section 15.307 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unlicensed Personal Communications Service Devices § 15.307 Coordination with fixed microwave service....

  7. 47 CFR 101.815 - Stations at temporary fixed locations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Stations at temporary fixed locations. 101.815 Section 101.815 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.815 Stations at...

  8. 47 CFR 101.815 - Stations at temporary fixed locations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Stations at temporary fixed locations. 101.815 Section 101.815 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.815 Stations at...

  9. 47 CFR 101.815 - Stations at temporary fixed locations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Stations at temporary fixed locations. 101.815 Section 101.815 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Local Television Transmission Service § 101.815 Stations at...

  10. 47 CFR 15.307 - Coordination with fixed microwave service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Coordination with fixed microwave service. 15.307 Section 15.307 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unlicensed Personal Communications Service Devices § 15.307 Coordination with fixed microwave service....

  11. 47 CFR 15.307 - Coordination with fixed microwave service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Coordination with fixed microwave service. 15.307 Section 15.307 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unlicensed Personal Communications Service Devices § 15.307 Coordination with fixed microwave service....

  12. 48 CFR 970.1504-1-6 - Calculating fixed fee.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Calculating fixed fee. 970.1504-1-6 Section 970.1504-1-6 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS Contracting by Negotiation 970.1504-1-6 Calculating fixed fee. (a) In recognition...

  13. Micro-beam friction liner and method of transferring energy

    DOEpatents

    Mentesana, Charles

    2007-07-17

    A micro-beam friction liner adapted to increase performance and efficiency and reduce wear in a piezoelectric motor or actuator or other device using a traveling or standing wave to transfer energy in the form of torque and momentum. The micro-beam friction liner comprises a dense array of micro-beam projections having first ends fixed relative to a rotor and second ends projecting substantially toward a plurality of teeth of a stator, wherein the micro-beam projections are compressed and bent during piezoelectric movement of the stator teeth, thereby storing the energy, and then react against the stator teeth to convert the stored energy stored to rotational energy in the rotor.

  14. Performance of laser inter-satellite links with dynamic beam waist adjustment.

    PubMed

    Song, Tianyu; Wang, Qian; Wu, Ming-Wei; Kam, Pooi-Yuen

    2016-05-30

    In this paper, we propose the idea of dynamic beam waist adjustment for laser inter-satellite communications, and study the performance of this dynamic-beam scheme. The beam waist adjustment is based on continuous detection of the instantaneous pointing error angle, which is performed at the transmitter side. Using a square to approximate the circular detector region, we obtain a closed-form expression for calculating the proportion of power that can be collected by the receiver aperture, and derive a simple algebraic solution for the optimum dynamic beam waist. Due to its simple form, the dynamic beam waist value can be computed in real time at the transmitter, and therefore, the adjustment is practically implementable. It is shown that the performance of laser inter-satellite links with dynamic beam waist is better than that with fixed beam waist. PMID:27410117

  15. On the use of consistent approximations for the optimal design of beams

    SciTech Connect

    Polak, E.; Neto, C.K.

    1994-12-31

    Most optimal design problems can only be solved through discretization. One solution strategy is to expand the original problem into an infinite sequence of finite dimensional, approximating nonlinear programming problems, which can be solved using standard algorithms. In this paper, an expansion strategy based on the concept of consistent approximations is proposed for certain optimal beam design problems, where the beam is modelled using Euler-Bernoulli beam theory. It is shown that any accumulation point of the sequence of the stationary points of the family of approximating problems is a stationary point of the original, infinite-dimensional problem. Numerical results are presented for problems of optimal design of fixed beams.

  16. Measurements and simulations of emittance growth of an H - beam from an LBL volume source

    NASA Astrophysics Data System (ADS)

    Gammel, G.; Ng, Y.; Debiak, T.; Kuehne, F.

    1991-05-01

    Measurements of emittance and emittance growth in an H - beam extracted from an LBL volume source will be presented. Effects of introducing cesium into the arc chamber will be shown. Some differences are noted depending on whether cesium is actively entering the chamber, or whether the source is running on residual Cs. Also, the effect of beam perveance will be shown. At a fixed location, the dependence of emittance on perveance is similar to the dependence of beam width on perveance, as if emittance is proportional to beam divergence. This data will be compared with WOLF simulations of emittance growth at different currents, with a non-uniform initial current density distribution.

  17. Generating optical superimposed vortex beam with tunable orbital angular momentum using integrated devices

    PubMed Central

    Wang, Yu; Feng, Xue; Zhang, Dengke; Zhao, Peng; Li, Xiangdong; Cui, Kaiyu; Liu, Fang; Huang, Yidong

    2015-01-01

    An integrated device, which consists of a variable amplitude splitter and an orbital angular momentum (OAM) emitter, is proposed for the superposition of optical vortex beams. With fixed wavelength and power of incident beam, the OAM of the radiated optical superimposed vortex beam can be dynamically tuned. To verify the operating principle, the proposed device has been fabricated on the SOI substrate and experimentally measured. The experimental results confirm the tunability of superimposed vortex beams. Moreover, the ability of independently varying the OAM flux and the geometric distribution of intensity is illustrated and discussed with numerical simulation. We believe that this work would be promising in various applications. PMID:26190669

  18. Beam divergence changing mechanism for short-range inter-unmanned aerial vehicle optical communications.

    PubMed

    Heng, Kiang Huat; Zhong, Wen-De; Cheng, Tee Hiang; Liu, Ning; He, Yingjie

    2009-03-10

    The problems associated with using a single fixed beam divergence for short-range inter-unmanned aerial vehicle free-space optical communications are discussed. To overcome the problems, a beam divergence changing mechanism is proposed. Four different methods are then proposed to implement the beam divergence changing mechanism. The performance of these methods is evaluated in terms of transmission distance under adverse weather conditions. The results show that the performance is greatly improved when the beam divergence changing mechanism is used. PMID:19277090

  19. Fixed points for weakly inward mappings in Banach spaces

    NASA Astrophysics Data System (ADS)

    Xu, Shaoyuan; Jia, Baoguo; Li, Guo-Zhen

    2006-07-01

    S. Hu and Y. Sun [S. Hu, Y. Sun, Fixed point index for weakly inward mappings, J. Math. Anal. Appl. 172 (1993) 266-273] defined the fixed point index for weakly inward mappings, investigated its properties and studied the fixed points for such mappings. In this paper, following S. Hu and Y. Sun, we continue to investigate boundary conditions, under which the fixed point index for the completely continuous and weakly inward mapping, denoted by i(A,[Omega],P), is equal to 1 or 0. Correspondingly, we can obtain some new fixed point theorems of the completely continuous and weakly inward mappings and existence theorems of solutions for the equations Ax=[mu]x, which extend many famous theorems such as Leray-Schauder's theorem, Rothe's two theorems, Krasnoselskii's theorem, Altman's theorem, Petryshyn's theorem, etc., to the case of weakly inward mappings. In addition, our conclusions and methods are different from the ones in many recent works.

  20. [Is it possible to combine fixed therapeutic associations?].

    PubMed

    Nordmann, J-P

    2009-03-01

    The number of fixed associations to treat intraocular pressure has increased over the recent years, to improve patient's treatment adherence. They are generally considered as comparable to the same components administered separately with, in some cases, less side effects. It could thus be appealing to combine fixed associations to reduce these side effects and retain efficacy. However, almost all fixed associations contain timolol, a beta blocker, with a risk of an excessive beta blocking dose and related systemic adverse drug reactions. Several fixed-associations contain a prostaglandin analogue. Their combination would not have a superior efficacy to one fixed combination taken alone. Furthermore, an increased risk or incidence of adverse drug reactions would appear. Specific clinical studies are required before recommending their use in daily clinical practice. PMID:19515336

  1. Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

    SciTech Connect

    Zhu, Xianfang Li, Lunxiong; Gong, Huimin; Yang, Lan; Sun, Chenghua

    2014-09-01

    Electron beam-induced nanoinstabilities of pristine double-walled carbon nanotubes (DWCNTs) of two different configurations, one fixed at both ends and another fixed at only one end, were in-situ investigated in transmission electron microscope at room temperature. It was observed that the DWCNT fixed at both ends shrank in its diameter uniformly. Meanwhile, the DWCNT fixed at only one end intriguingly shrank preferentially from its free cap end along its axial direction whereas its diameter shrinkage was offset. A mechanism of “diffusion” along with “evaporation” at room temperature which is driven by the nanocurvature of the DWCNTs, and the athermal activation induced by the electron beam was proposed to elucidate the observed phenomena. The effect of the interlayer interaction of the DWCNTs was also discussed.

  2. Development of laser beam injection system for the Edge Thomson Scattering (ETS) in ITER

    NASA Astrophysics Data System (ADS)

    Yatsuka, E.; Hatae, T.; Suitoh, S.; Ohara, M.; Hagita, K.; Inoue, K.; Bassan, M.; Walsh, M.; Itami, K.

    2016-01-01

    This paper focuses on the design and development of the laser injection system for the ITER Edge Thomson Scattering system (ETS). The ITER ETS achieves a temporal resolution of 100 Hz by firing two 50 Hz laser beams alternatively. The use of dual lasers enables us to perform the Thomson scattering measurements at a temporal resolution of 50 Hz in case that one of the laser systems stops functioning. A new type of beam combiner was developed to obtain a single beam that is collinear and fixed linearly polarized from two laser beams using a motor-driven rotating half-wave plate. The rotating half-wave plate method does not induce misalignment even if the rotating mechanism malfunctions. The combined beam is relayed from the diagnostic hall to the plasma using mirror optics and is absorbed at the beam dump integrated on the inner blanket. The beam alignment system was designed to direct the laser beam onto the center of the beam dump head. The beam position at the beam dump is monitored by four alignment laser beams which propagate parallel to the diagnostic Nd:YAG laser beam and imaging systems installed outside the diagnostic port.

  3. Backprojection filtering for variable orbit fan-beam tomography

    SciTech Connect

    Gullberg, G.T.; Zeng, G.L.

    1995-08-01

    Backprojection filtering algorithms are presented for three variable Orbit fan-beam geometries. Expressions for the fan beam projection and backprojection operators are given for a flat detector fan-beam geometry with fixed focal length, with variable focal length, and with fixed focal length and off-center focusing. Backprojection operators are derived for each geometry using transformation of coordinates to transform from a parallel geometry backprojector to a fan-beam backprojector for the appropriate geometry. The backprojection operator includes a factor which is a function of the coordinates of the projection ray and the coordinates of the pixel in the backprojected image. The backprojection filtering algorithm first backprojects the variable orbit fan-beam projection data using the appropriately derived backprojector to obtain a 1/r blurring of the original image then takes the two-dimensional (2D) Fast Fourier Transform (FFT) of the backprojected image, then multiples the transformed image by the 2D ramp filter function, and finally takes the inverse 2D FFT to obtain the reconstructed image. Computer simulations verify that backprojectors with appropriate weighting give artifact free reconstructions of simulated line integral projections. Also, it is shown that it is not necessary to assume a projection model of line integrals, but the projector and backprojector can be defined to model the physics of the imaging detection process. A backprojector for variable orbit fan-beam tomography with fixed focal length is derived which includes an additional factor which is a function of the flux density along the flat detector. It is shown that the impulse response for the composite of the projection and backprojection operations is equal to 1/r.

  4. Laser beam shaping techniques

    SciTech Connect

    DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

    2000-03-16

    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  5. Particle beam injection system

    DOEpatents

    Jassby, Daniel L.; Kulsrud, Russell M.

    1977-01-01

    This invention provides a poloidal divertor for stacking counterstreaming ion beams to provide high intensity colliding beams. To this end, method and apparatus are provided that inject high energy, high velocity, ordered, atomic deuterium and tritium beams into a lower energy, toroidal, thermal equilibrium, neutral, target plasma column that is magnetically confined along an endless magnetic axis in a strong restoring force magnetic field having helical field lines to produce counterstreaming deuteron and triton beams that are received bent, stacked and transported along the endless axis, while a poloidal divertor removes thermal ions and electrons all along the axis to increase the density of the counterstreaming ion beams and the reaction products resulting therefrom. By balancing the stacking and removal, colliding, strong focused particle beams, reaction products and reactions are produced that convert one form of energy into another form of energy.

  6. Auctionable fixed transmission rights for congestion management

    NASA Astrophysics Data System (ADS)

    Alomoush, Muwaffaq Irsheid

    the transaction by the ISO, take a decision to expand the existing system, or retain the original structure of the system. Also, the thesis investigates the impact of wheeling transactions on congestion management, where we present a generalized mathematical model for the Fixed Transmission Right (FTR) auction. The auction guarantees FTR availability to all participants on a non-discriminatory basis, in which system users are permitted to buy, sell and trade FTRs through an auction. When FTRs are utilized with LMPs, they increase the efficient use of the transmission system and let a transmission customer gain advantageous features such as acquiring a mechanism to offset the extra cost due to congestion charges, providing financial and operational certainty and making system users pay for the actual use of the congested paths. The thesis also highlighted FTR trading in secondary markets to self-arrange access across different paths, create long-term transmission rights and provide more commercial certainty.

  7. Refracting type laser beam scanner with minimum across-scan error

    NASA Astrophysics Data System (ADS)

    Khattak, Anwar S.

    1993-11-01

    An economical refracting type laser beam scanning device, exhibiting a minimum across-scan error without corrective measures, is described. The main structural assembly of the device consists of a rotating prism, a fixed spherical lens, and a fixed convex spherical auxiliary reflector (SAR). Trigonometric equations are developed to determine the radius of curvature of the SAR and the size of the exit pupil. Resolution analyses are presented for a specific set of design parameters.

  8. On the relation between incident and emergent light beams of optical fibers. II. Single-mode fibers.

    NASA Astrophysics Data System (ADS)

    Imai, H.; Sakurai, T.

    1999-03-01

    The change in F-ratio when a beam of light goes through an optical fiber is examined for a single-mode fiber (core radius = 9 μm). A previous study (Makita and Imai 1988) showed that, for multi-mode fibers, the F-ratio of the output beam is smaller (i.e. the beam spreads) than the F-ratio of the input beam. Such degradation in F-ratio is not seen in a single-mode fiber because the output beam's F-ratio is fixed by the mode propagating in the fiber.

  9. ALEX neutral beam probe

    SciTech Connect

    Pourrezaei, K.

    1982-01-01

    A neutral beam probe capable of measuring plasma space potential in a fully 3-dimensional magnetic field geometry has been developed. This neutral beam was successfully used to measure an arc target plasma contained within the ALEX baseball magnetic coil. A computer simulation of the experiment was performed to refine the experimental design and to develop a numerical model for scaling the ALEX neutral beam probe to other cases of fully 3-dimensional magnetic field. Based on this scaling a 30 to 50 keV neutral cesium beam probe capable of measuring space potential in the thermal barrier region of TMX Upgrade was designed.

  10. Power beaming options

    NASA Technical Reports Server (NTRS)

    Rather, John D. G.

    1989-01-01

    Some large scale power beaming applications are proposed for the purpose of stimulating research. The first proposal is for a combination of large phased arrays on the ground near power stations and passive reflectors in geostationary orbit. The systems would beam excess electrical power in microwave form to areas in need of electrical power. Another proposal is to build solar arrays in deserts and beam the energy around the world. Another proposal is to use lasers to beam energy from earth to orbiting spacecraft.

  11. Broad beam ion implanter

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

  12. Broad beam ion implanter

    DOEpatents

    Leung, K.N.

    1996-10-08

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes. 6 figs.

  13. (Pulsed electron beam precharger)

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1990-01-01

    This report discusses the following topics on electron beam guns: Precharger Modification; Installation of Charge vs. Radius Apparatus; High Concentration Aerosol Generation; and Data Acquisition and Analysis System.

  14. Astigmatic Bessel laser beams

    NASA Astrophysics Data System (ADS)

    Khonina, S. N.; Kotlyar, V. V.; Soifer, V. A.; Jefimovs, K.; Pääkkönen, P.; Turunen, J.

    2004-05-01

    The oblique incidence of a He-Ne laser beam onto a phase-only diffractive optical element (DOE) that simultaneously produces several unimode different-order Bessel beams propagating at various angles with respect to the optical axis is studied theoretically and experimentally. It is shown that, under obliquely incident illumination of a DOE that forms Bessel beams, the resulting astigmatic diffraction pattern can be used to unambiguously identify the direction of the Bessel beam's phase rotation and the order of the Bessel mode.

  15. Long-Range Beam-Beam Compensation in RHIC

    SciTech Connect

    Kim, Hyung Jin; Sen, Tanaji; Fischer, Wolfram; /Brookhaven

    2010-05-01

    In order to avoid the effects of long-range beam-beam interactions which produce beam blow-up and deteriorate beam life time, a compensation scheme with current carrying wires has been proposed. Two long-range beam-beam compensators were installed in RHIC rings in 2006. The effects of the compensators have been experimentally investigated. An indication was observed that the compensators are beneficial to beam life time in measurements performed in RHIC during 2009. In this paper, we report the effects of wire compensator on beam loss and emittance for proton-proton beams at collision energy.

  16. Observation of longitudinal diffusion and cooling due to intra-beam scattering at the Fermilab Recycler Ring

    SciTech Connect

    Hu, M.; Nagaitsev, S.; /Fermilab

    2005-05-01

    The Fermilab Recycler Ring is a high-vacuum fixed energy antiproton storage ring with both stochastic (at present) and the future electron cooling systems. In this paper the technique for diffusion rate measurement, beam parameters and the analysis of data are presented, as well as the effect of intra-beam scattering on the operational considerations for the storage and cooling of the antiproton beam in the Recycler.

  17. Beam-centric algorithm for pretreatment patient position correction in external beam radiation therapy

    SciTech Connect

    Bose, Supratik; Shukla, Himanshu; Maltz, Jonathan

    2010-05-15

    Purpose: In current image guided pretreatment patient position adjustment methods, image registration is used to determine alignment parameters. Since most positioning hardware lacks the full six degrees of freedom (DOF), accuracy is compromised. The authors show that such compromises are often unnecessary when one models the planned treatment beams as part of the adjustment calculation process. The authors present a flexible algorithm for determining optimal realizable adjustments for both step-and-shoot and arc delivery methods. Methods: The beam shape model is based on the polygonal intersection of each beam segment with the plane in pretreatment image volume that passes through machine isocenter perpendicular to the central axis of the beam. Under a virtual six-DOF correction, ideal positions of these polygon vertices are computed. The proposed method determines the couch, gantry, and collimator adjustments that minimize the total mismatch of all vertices over all segments with respect to their ideal positions. Using this geometric error metric as a function of the number of available DOF, the user may select the most desirable correction regime. Results: For a simulated treatment plan consisting of three equally weighted coplanar fixed beams, the authors achieve a 7% residual geometric error (with respect to the ideal correction, considered 0% error) by applying gantry rotation as well as translation and isocentric rotation of the couch. For a clinical head-and-neck intensity modulated radiotherapy plan with seven beams and five segments per beam, the corresponding error is 6%. Correction involving only couch translation (typical clinical practice) leads to a much larger 18% mismatch. Clinically significant consequences of more accurate adjustment are apparent in the dose volume histograms of target and critical structures. Conclusions: The algorithm achieves improvements in delivery accuracy using standard delivery hardware without significantly increasing

  18. A new compact fixed-point blackbody furnace

    SciTech Connect

    Hiraka, K.; Oikawa, H.; Shimizu, T.; Kadoya, S.; Kobayashi, T.; Yamada, Y.; Ishii, J.

    2013-09-11

    More and more NMIs are realizing their primary scale themselves with fixed-point blackbodies as their reference standard. However, commercially available fixed-point blackbody furnaces of sufficient quality are not always easy to obtain. CHINO Corp. and NMIJ, AIST jointly developed a new compact fixed-point blackbody furnace. The new furnace has such features as 1) improved temperature uniformity when compared to previous products, enabling better plateau quality, 2) adoption of the hybrid fixed-point cell structure with internal insulation to improve robustness and thereby to extend lifetime, 3) easily ejectable and replaceable heater unit and fixed-point cell design, leading to reduced maintenance cost, 4) interchangeability among multiple fixed points from In to Cu points. The replaceable cell feature facilitates long term maintenance of the scale through management of a group of fixed-point cells of the same type. The compact furnace is easily transportable and therefore can also function as a traveling standard for disseminating the radiation temperature scale, and for maintaining the scale at the secondary level and industrial calibration laboratories. It is expected that the furnace will play a key role of the traveling standard in the anticipated APMP supplementary comparison of the radiation thermometry scale.

  19. Procrastination by pigeons with fixed-interval response requirements.

    PubMed

    Mazur, J E

    1998-03-01

    Two experiments studied the phenomenon of procrastination, in which pigeons chose a larger, more delayed response requirement over a smaller, more immediate response requirement. The response requirements were fixed-interval schedules that did not lead to an immediate food reinforcer, but that interrupted a 55-s period in which food was delivered at random times. The experiments used an adjusting-delay procedure in which the delay to the start of one fixed-interval requirement was varied over trials to estimate an indifference point--a delay at which the two alternatives were chosen about equally often. Experiment 1 found that as the delay to a shorter fixed-interval requirement was increased, the adjusting delay to a longer fixed-interval requirement also increased, and the rate of increase depended on the duration of the longer fixed-interval requirement. Experiment 2 found a strong preference for a fixed delay of 10 s to the start of a fixed-interval requirement compared to a mixed delay of either 0 or 20 s. The results help to distinguish among different equations that might describe the decreasing effectiveness of a response requirement with increasing delay, and they suggest that delayed reinforcers and delayed response requirements have symmetrical but opposite effects on choice. PMID:9540230

  20. Procrastination by pigeons with fixed-interval response requirements.

    PubMed Central

    Mazur, J E

    1998-01-01

    Two experiments studied the phenomenon of procrastination, in which pigeons chose a larger, more delayed response requirement over a smaller, more immediate response requirement. The response requirements were fixed-interval schedules that did not lead to an immediate food reinforcer, but that interrupted a 55-s period in which food was delivered at random times. The experiments used an adjusting-delay procedure in which the delay to the start of one fixed-interval requirement was varied over trials to estimate an indifference point--a delay at which the two alternatives were chosen about equally often. Experiment 1 found that as the delay to a shorter fixed-interval requirement was increased, the adjusting delay to a longer fixed-interval requirement also increased, and the rate of increase depended on the duration of the longer fixed-interval requirement. Experiment 2 found a strong preference for a fixed delay of 10 s to the start of a fixed-interval requirement compared to a mixed delay of either 0 or 20 s. The results help to distinguish among different equations that might describe the decreasing effectiveness of a response requirement with increasing delay, and they suggest that delayed reinforcers and delayed response requirements have symmetrical but opposite effects on choice. PMID:9540230

  1. N2-fixing red alder indirectly accelerates ecosystem nitrogen cycling

    USGS Publications Warehouse

    Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

    2012-01-01

    Symbiotic N2-fixing tree species can accelerate ecosystem N dynamics through decomposition via direct pathways by producing readily decomposed leaf litter and increasing N supply to decomposers, as well as via indirect pathways by increasing tissue and detrital N in non-fixing vegetation. To evaluate the relative importance of these pathways, we compared three-year decomposition and N dynamics of N2-fixing red alder leaf litter (2.34 %N) to both low-N (0.68 %N) and high-N (1.21 %N) litter of non-fixing Douglas-fir, and decomposed each litter source in four forests dominated by either red alder or Douglas-fir. We also used experimental N fertilization of decomposition plots to assess elevated N availability as a potential mechanism of N2-fixer effects on litter mass loss and N dynamics. Direct effects of N2-fixing red alder on decomposition occurred primarily as faster N release from red alder than Douglas-fir litter, but direct increases in N supply to decomposers via fertilization did not stimulate decomposition of any litter. Fixed N indirectly influenced detrital dynamics by increasing Douglas-fir tissue and litter N concentrations, which accelerated litter N release without accelerating mass loss. By increasing soil N, tissue N, and the rate of N release from litter of non-fixers, we conclude that N2-fixing vegetation can indirectly foster plant-soil feedbacks that contribute to the persistence of elevated N availability in terrestrial ecosystems.

  2. Automatic learning-based beam angle selection for thoracic IMRT

    SciTech Connect

    Amit, Guy; Marshall, Andrea; Purdie, Thomas G. Jaffray, David A.; Levinshtein, Alex; Hope, Andrew J.; Lindsay, Patricia; Pekar, Vladimir

    2015-04-15

    coverage and organ at risk sparing and were superior over plans produced with fixed sets of common beam angles. The great majority of the automatic plans (93%) were approved as clinically acceptable by three radiation therapy specialists. Conclusions: The results demonstrated the feasibility of utilizing a learning-based approach for automatic selection of beam angles in thoracic IMRT planning. The proposed method may assist in reducing the manual planning workload, while sustaining plan quality.

  3. Autonomous beam alignment for coherent Doppler lidar with multielement detectors.

    PubMed

    Frehlich, R

    1999-11-20

    Autonomous beam alignment for coherent Doppler lidar requires accurate information about optical misalignment and optical aberrations. A multielement heterodyne detector provides the required information without a loss in overall system performance. The effects of statistical variations from the random backscattered field (speckle field) are determined with computer simulations for both ground-based operation with a fixed calibration target and for space-based operation with random target backscatter. PMID:18324236

  4. Meshless method for solving fixed boundary problem of plasma equilibrium

    NASA Astrophysics Data System (ADS)

    Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi

    2015-07-01

    This study solves the Grad-Shafranov equation with a fixed plasma boundary by utilizing a meshless method for the first time. Previous studies have utilized a finite element method (FEM) to solve an equilibrium inside the fixed separatrix. In order to avoid difficulties of FEM (such as mesh problem, difficulty of coding, expensive calculation cost), this study focuses on the meshless methods, especially RBF-MFS and KANSA's method to solve the fixed boundary problem. The results showed that CPU time of the meshless methods was ten to one hundred times shorter than that of FEM to obtain the same accuracy.

  5. Follow-up problems with fixed appliances in pediatric dentistry.

    PubMed

    Ari, Timucin

    2015-03-01

    Fixed appliances are commonly used in managing early orthodontic problems. Despite their widespread use, they have the potential to impinge on the soft tissues, interfere with the eruption of adjacent teeth and become dislodged or broken. These two case reports present the poor outcomes of fixed appliance treatments if the patient fails to attend follow-up appointments. A successful outcome of treatment with fixed appliances depends upon proper patient selection and the communication skills of the dentist to help patients/parents understand the importance of regular checkups. PMID:25928968

  6. Implementation of depolarization due to beam-beam effects in the beam-beam interaction simulation tool GUINEA-PIG++

    NASA Astrophysics Data System (ADS)

    Rimbault, C.; Le Meur, G.; Blampuy, F.; Bambade, P.; Schulte, D.

    2009-12-01

    Depolarization is a new feature in the beam-beam simulation tool GUINEA-PIG++ (GP++). The results of this simulation are studied and compared with another beam-beam simulation tool, CAIN, considering different beam parameters for the International Linear Collider (ILC) with a centre-of-mass energy of 500 GeV.

  7. Beam Diagnostics for FACET

    SciTech Connect

    Li, S.Z.; Hogan, M.J.; /SLAC

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to about 20 {micro}m long and focussed to about 10 {micro}m wide. Characterization of the beam-plasma interaction requires complete knowledge of the incoming beam parameters on a pulse-to-pulse basis. FACET diagnostics include Beam Position Monitors, Toroidal current monitors, X-ray and Cerenkov based energy spectrometers, optical transition radiation (OTR) profile monitors and coherent transition radiation (CTR) bunch length measurement systems. The compliment of beam diagnostics and their expected performance are reviewed. Beam diagnostic measurements not only provide valuable insights to the running and tuning of the accelerator but also are crucial for the PWFA experiments in particular. Beam diagnostic devices are being set up at FACET and will be ready for beam commissioning in summer 2011.

  8. Beam Injection into RHIC

    NASA Astrophysics Data System (ADS)

    Fischer, W.; Hahn, H.; Mackay, W. W.; Tsoupas, N.

    1997-05-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. We describe the injection zone and its bottlenecks, the application program to steer the beam and the injection kickers. We report on the commissioning of the injection systems and on measurements of the kickers.

  9. Switchable circular beam deflectors

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobing; Joshi, Pankaj; Tan, Jin-Yi; De Smet, Jelle; Cuypers, Dieter; Baghdasaryan, Tigran; Vervaeke, Michael; Thienpont, Hugo; De Smet, Herbert

    2016-04-01

    In this work, we report two types of electrically tunable photonic devices with circularly symmetric polarization independent beam steering performance (beam condensing resp. beam broadening). The devices consist of circular micro grating structures combined with nematic liquid crystal (LC) layers with anti-parallel alignment. A single beam deflector converts a polarized and monochromatic green laser beam (λ =543.5 nm) into a diffraction pattern, with the peak intensity appearing at the third order when 0~{{V}\\text{pp}} is applied and at the zeroth order (no deflection) for voltages above 30~{{V}\\text{pp}} . Depending on the shape of the grating structure (non-inverted or inverted), the deflection is inwards or outwards. Both grating types can be made starting from the same diamond-tooled master mold. A polarized white light beam is symmetrically condensed resp. broadened over 2° in the off state and is passed through unchanged in the on state. By stacking two such devices with mutually orthogonal LC alignment layers, polarization independent switchable circular beam deflectors are realized with a high transmittance (>80%), and with the same beam steering performance as the polarization dependent single devices.

  10. Picosecond beam monitor

    DOEpatents

    Schutt, D.W.; Beck, G.O.

    1974-01-01

    The current in the beam of a particle accelerator is monitored with picosecond resolution by causing the beam to impinge upon the center conductor of a coaxial line, generating a pulse of electromagnetic energy in response thereto. This pulse is detected by means such as a sampling oscilloscope. (Official Gazette)

  11. Ion Beam Propulsion Study

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  12. Pulsed electron beam precharger

    SciTech Connect

    Finney, W.C.; Shelton, W.N.

    1991-01-01

    Electron beam precharging of a high resistivity aerosol was successfully performed under a range of experimental conditions during Quarter Six of the contract. The initial E-beam particle precharging experiments completed this term were designed to extend the efficiency of particle charging and collection using a fine, monodisperse aerosol at relatively large loadings in the FSU Electron Beam Precipitator wind tunnel. There are several reasons for doing this: (1) to re-establish a baseline performance criterion for comparison to other runs, (2) to test several recently upgraded or repaired subsystems, and (3) to improve upon the collection efficiency of the electron beam precipitator when testing precharging effectiveness with a very high resistivity, moderate-to-high dust concentration. In addition, these shakedown runs were used to determine a set of suitable operational parameters for the wind tunnel, the electrostatic collecting sections, and the MINACC E-beam accelerator. These parameters will normally be held constant while the precharging parameters are varied to produce an optimum particle charge. The electron beam precharging investigation performed during the period covered by Quarter Six used virtually the same experimental apparatus and procedures as in previous contract work, and these are described for review in this report. This investigation was part of an experimental effort which ran nearly continuously for nine months, encompassing work on the electrostatic collecting section, electron beam precharger, and particle charge-to-radius measuring apparatus. A summary of the work on dc electron beam precipitation is presented here.

  13. Progress of Multi-Beam Long Trace-Profiler Development

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail; Kilaru, Kiranmayee; Merthe, Daniel J.; Kester, Thomas; McKinney, Wayne R.; Takacs, Peter Z.; Yashchuk, Valeriy V.

    2012-01-01

    The multi-beam long trace profiler (LTP) under development at NASA s Marshall Space Flight Center[1] is designed to increase the efficiency of metrology of replicated X-ray optics. The traditional LTP operates on a single laser beam that scans along the test surface to detect the slope errors. While capable of exceptional surface slope accuracy, the LTP single beam scanning has slow measuring speed. As metrology constitutes a significant fraction of the time spent in optics production, an increase in the efficiency of metrology helps in decreasing the cost of fabrication of the x-ray optics and in improving their quality. Metrology efficiency can be increased by replacing the single laser beam with multiple beams that can scan a section of the test surface at a single instance. The increase in speed with such a system would be almost proportional to the number of laser beams. A collaborative feasibility study has been made and specifications were fixed for a multi-beam long trace profiler. The progress made in the development of this metrology system is presented.

  14. Laser-based profile and energy monitor for H beams

    SciTech Connect

    Connolly,R.; Alessi, J.; Bellavia, S.; Dawson, C.; Degen, C.; Meng, W.; Raparia, D.; Russo, T.; Tsoupas, N.

    2008-09-29

    A beam profile and energy monitor for H{sup -} beams based on laser photoneutralization was built at Brookhaven National Laboratory (BNL)* for use on the High Intensity Neutrino Source (HMS) at Fermilab. An H{sup -} ion has a first ionization potential of 0.75eV and can be neutralized by light from a Nd:YAG laser ({lambda}=1064nm). To measure beam profiles, a narrow laser beam is stepped across the ion beam, removing electrons from the portion of the H{sup -} beam intercepted by the laser. These electrons are channeled into a Faraday cup by a curved axial magnetic field. To measure the energy distribution of the electrons, the laser position is fixed and the voltage on a screen in front of the Faraday cup is raised in small steps. We present a model which reproduces the measured energy spectrum from calculated beam energy and space-charge fields. Measurements are reported from experiments in the BNL linac MEBT at 750keV.

  15. Evaluation of tilted cone-beam CT orbits in the development of a dedicated hybrid mammotomograph

    PubMed Central

    Crotty, D J; McKinley, R L; Tornai, M P

    2010-01-01

    A compact dedicated 3D breast SPECT-CT (mammotomography) system is currently under development. In its initial prototype, the cone-beam CT sub-system is restricted to a fixed-tilt circular rotation around the patient’s pendant breast. This study evaluated stationary-tilt angles for the CT subsystem that will enable maximal volumetric sampling and viewing of the breast and chest wall. Images of geometric/anthropomorphic phantoms were acquired using various fixed-tilt circular and 3D sinusoidal trajectories. The iteratively reconstructed images showed more distortion and attenuation coefficient inaccuracy from tilted cone-beam orbits than from the complex trajectory. Additionally, line profiles illustrated cupping artifacts in planes distal to the central plane of the tilted cone-beam, otherwise not apparent for images acquired with complex trajectories. This indicates that undersampled cone-beam data may be an additional cause of cupping artifacts. High-frequency objects could be distinguished for all trajectories, but their shapes and locations were corrupted by out-of-plane frequency information. Although more acrylic balls were visualized with a fixed-tilt and nearly flat cone-beam at the posterior of the breast, 3D complex trajectories have less distortion and more complete sampling throughout the reconstruction volume. While complex trajectories would ideally be preferred, negatively fixed-tilt source–detector configuration demonstrates minimally distorted patient images. PMID:19478374

  16. Observing a light dark matter beam with neutrino experiments

    NASA Astrophysics Data System (ADS)

    Deniverville, Patrick; Pospelov, Maxim; Ritz, Adam

    2011-10-01

    We consider the sensitivity of fixed-target neutrino experiments at the luminosity frontier to light stable states, such as those present in models of MeV-scale dark matter. To ensure the correct thermal relic abundance, such states must annihilate via light mediators, which in turn provide an access portal for direct production in colliders or fixed targets. Indeed, this framework endows the neutrino beams produced at fixed-target facilities with a companion “dark matter beam,” which may be detected via an excess of elastic scattering events off electrons or nuclei in the (near-)detector. We study the high-luminosity proton fixed-target experiments at LSND and MiniBooNE, and determine that the ensuing sensitivity to light dark matter generally surpasses that of other direct probes. For scenarios with a kinetically-mixed U(1)' vector mediator of mass mV, we find that a large volume of parameter space is excluded for mDM˜1-5MeV, covering vector masses 2mDM≲mV≲mη and a range of kinetic mixing parameters reaching as low as κ˜10-5. The corresponding MeV-scale dark matter scenarios motivated by an explanation of the galactic 511 keV line are thus strongly constrained.

  17. Fix and forget or fix and report: a qualitative study of tensions at the front line of incident reporting

    PubMed Central

    Hewitt, Tanya Anne; Chreim, Samia

    2015-01-01

    Introduction Practitioners frequently encounter safety problems that they themselves can resolve on the spot. We ask: when faced with such a problem, do practitioners fix it in the moment and forget about it, or do they fix it in the moment and report it? We consider factors underlying these two approaches. Methods We used a qualitative case study design employing in-depth interviews with 40 healthcare practitioners in a tertiary care hospital in Ontario, Canada. We conducted a thematic analysis, and compared the findings with the literature. Results ‘Fixing and forgetting’ was the main choice that most practitioners made in situations where they faced problems that they themselves could resolve. These situations included (A) handling near misses, which were seen as unworthy of reporting since they did not result in actual harm to the patient, (B) prioritising solving individual patients’ safety problems, which were viewed as unique or one-time events and (C) encountering re-occurring safety problems, which were framed as inevitable, routine events. In only a few instances was ‘fixing and reporting’ mentioned as a way that the providers dealt with problems that they could resolve. Conclusions We found that generally healthcare providers do not prioritise reporting if a safety problem is fixed. We argue that fixing and forgetting patient safety problems encountered may not serve patient safety as well as fixing and reporting. The latter approach aligns with recent calls for patient safety to be more preventive. We consider implications for practice. PMID:25749025

  18. BEAMS3D Neutral Beam Injection Model

    NASA Astrophysics Data System (ADS)

    McMillan, Matthew; Lazerson, Samuel A.

    2014-09-01

    With the advent of applied 3D fields in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous slowing down, and pitch angle scattering are modeled with the ADAS atomic physics database. Elementary benchmark calculations are presented to verify the collisionless particle orbits, NBI model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields. Notice: this manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  19. First Beam to FACET

    SciTech Connect

    Erickson, R.; Clarke, C.; Colocho, W.; Decker, F.-J.; Hogan, M.; Kalsi, S.; Lipkowitz, N.; Nelson, J.; Phinney, N.; Schuh, P.; Sheppard, J.; Smith, H.; Smith, T.; Stanek, M.; Turner, J.; Warren, J.; Weathersby, S.; Wienands, U.; Wittmer, W.; Woodley, M.; Yocky, G.; /SLAC

    2011-12-13

    The SLAC 3km linear electron accelerator has been reconfigured to provide a beam of electrons to the new Facility for Advanced Accelerator Experimental Tests (FACET) while simultaneously providing an electron beam to the Linac Coherent Light Source (LCLS). On June 23, 2011, the first electron beam was transported through this new facility. Commissioning of FACET is in progress. On June 23, 2011, an electron beam was successfully transported through the new FACET system to a dump in Sector 20 in the linac tunnel. This was achieved while the last third of the linac, operating from the same control room, but with a separate injector system, was providing an electron beam to the Linac Coherent Light Source (LCLS), demonstrating that concurrent operation of the two facilities is practical. With the initial checkout of the new transport line essentially complete, attention is now turning toward compressing the electron bunches longitudinally and focusing them transversely to support a variety of accelerator science experiments.

  20. Sheet electron beam tester

    NASA Astrophysics Data System (ADS)

    Spear, Alexander Grenbeaux

    The DARPA HiFIVE project uses a pulsed electron sheet beam gun to power a traveling wave tube amplifier operating at 220 GHz. Presented is a method for characterizing the high current density 0.1 mm by 1 mm sheet electron beam. A tungsten tipped probe was scanned through the cross section of the sheet electron beam inside of a vacuum vessel. The probe was controlled with sub-micron precision using stepper motors and LabView computer control while boxcar averaging hardware sampled the pulsed beam. Matlab algorithms were used to interpret the data, calculate beam dimensions and current density, and create 2-dimensional cross section images. Full characterization of two separate HiFIVE sheet electron guns was accomplished and is also presented.

  1. Laser beam alignment system

    DOEpatents

    Kasner, William H.; Racki, Daniel J.; Swenson, Clark E.

    1984-01-01

    A plurality of pivotal reflectors direct a high-power laser beam onto a workpiece, and a rotatable reflector is movable to a position wherein it intercepts the beam and deflects a major portion thereof away from its normal path, the remainder of the beam passing to the pivotal reflectors through an aperture in the rotating reflector. A plurality of targets are movable to positions intercepting the path of light traveling to the pivotal reflectors, and a preliminary adjustment of the latter is made by use of a low-power laser beam reflected from the rotating reflector, after which the same targets are used to make a final adjustment of the pivotal reflectors with the portion of the high-power laser beam passed through the rotating reflector.

  2. Beam director design report

    SciTech Connect

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  3. Investigation of ion-beam machining methods for replicated x-ray optics

    NASA Technical Reports Server (NTRS)

    Drueding, Thomas W.

    1996-01-01

    The final figuring step in the fabrication of an optical component involves imparting a specified contour onto the surface. This can be expensive and time consuming step. The recent development of ion beam figuring provides a method for performing the figuring process with advantages over standard mechanical methods. Ion figuring has proven effective in figuring large optical components. The process of ion beam figuring removes material by transferring kinetic energy from impinging neutral particles. The process utilizes a Kaufman type ion source, where a plasma is generated in a discharge chamber by controlled electric potentials. Charged grids extract and accelerate ions from the chamber. The accelerated ions form a directional beam. A neutralizer outside the accelerator grids supplies electrons to the positive ion beam. It is necessary to neutralize the beam to prevent charging workpieces and to avoid bending the beam with extraneous electro-magnetic fields. When the directed beam strikes the workpiece, material sputters in a predicable manner. The amount and distribution of material sputtered is a function of the energy of the beam, material of the component, distance from the workpiece, and angle of incidence of the beam. The figuring method described here assumes a constant beam removal, so that the process can be represented by a convolution operation. A fixed beam energy maintains a constant sputtering rate. This temporally and spatially stable beam is held perpendicular to the workpiece at a fixed distance. For non-constant removal, corrections would be required to model the process as a convolution operation. Specific figures (contours) are achieved by rastering the beam over the workpiece at varying velocities. A unique deconvolution is performed, using series-derivative solution developed for the system, to determine these velocities.

  4. Energy spectrum control for modulated proton beams

    SciTech Connect

    Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

    2009-06-15

    In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to {+-}21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than {+-}3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies.

  5. Energy spectrum control for modulated proton beams.

    PubMed

    Hsi, Wen C; Moyers, Michael F; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E; Farr, Jonathan B; Mascia, Anthony E; Schreuder, Andries N

    2009-06-01

    In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to +/-21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than +/-3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies. PMID:19610318

  6. Neurochemical changes correlated with behavior maintained under fixed-interval and fixed-ratio schedules of reinforcement.

    PubMed Central

    Barrett, J E; Hoffmann, S M

    1991-01-01

    Key pecking of 4 pigeons was maintained under a multiple 3-min fixed-interval, 30-response fixed-ratio schedule of food presentation. Only one schedule was in effect during an experimental session, and each was correlated with a different keylight stimulus and location (left vs. right). The different schedule components alternated across days or weeks. Cerebrospinal fluid was collected from chronically implanted intracerebroventricular cannulae following sessions with the different schedules, as well as following sessions in which reinforcement was withheld (extinction), when response-independent food was delivered, and when the experimental chamber was dark and there were no scheduled events. Metabolites of the neurotransmitters serotonin, norepinephrine, and dopamine were assayed in cerebrospinal fluid using high-performance liquid chromatography with electrochemical detection. Compared to the fixed-ratio condition, responding maintained under the fixed-interval schedule resulted in consistently higher levels of the serotonin metabolite 5-hydroxyindoleacetic acid and of the dopamine metabolite homovanillic acid in all pigeons. Levels of 3-methoxy-4-hydroxyphenylethylene glycol, a metabolite of norepinephrine, and dihydroxyphenylacetic acid, another dopamine metabolite, were also higher in 3 of the 4 pigeons following exposure to the fixed-interval schedules when compared to levels of these metabolites after exposure to the fixed-ratio schedule. Extinction of fixed-ratio responding resulted in large increases in 5-hydroxyindoleacetic acid compared to levels of this metabolite under the fixed-ratio schedule, whereas this serotonin metabolite decreased during extinction of responding under the fixed-interval schedule. Control procedures suggested that the neurochemical changes were not related to the rate of responding but were a function of the specific experimental conditions. Distinctive neurochemical changes that accompany schedule-controlled responding show the

  7. Proposal for continuously-variable neutrino beam energy for the NuMI facility

    SciTech Connect

    Kostin, Mikhail; Kopp, Sacha; Messier, Mark; Harris, Deborah A.; Hylen, Jim; Para, Adam; /Fermilab

    2006-07-01

    The NuMI Facility was intended to be flexibly changed between 3 energies of beams, LE, ME, and HE. However, the changeover requires extensive downtime to move and realign horns and the target. We propose to implement a flexible arrangement where the target can be remotely moved in the beamline direction to change the beam energy and the horns remain fixed. In addition to having the attractive feature of keeping the horn optics fixed, the motion of the target can be performed more quickly and hence on a more frequent basis. We discuss potential increases in statistics in the high energy region, systematic cross-checks available, and the improved beam monitoring capabilities with such variable energy beams.

  8. Simple circuit produces high-speed, fixed duration pulses

    NASA Technical Reports Server (NTRS)

    Garrahan, N. M.

    1965-01-01

    Circuit generates an output pulse of fixed width from a variable width input pulse. The circuit consists of a tunnel diode in parallel with an inductance driven by a constant current generator. It is used for pulsed communication equipment design.

  9. Towards the minimal nitrogen-fixing symbiotic genome.

    PubMed

    Sanjuán, Juan

    2016-09-01

    diCenzo and coworkers have reverse engineered a rhizobium into a non-nitrogen fixer, creating a genomic platform for gain-of-function genetics studies, which should aid to identify the minimal nitrogen fixing symbiotic genome. PMID:27188818

  10. Heavy flavor production at fixed target photo- and hadroproduction

    SciTech Connect

    Kwan, S.

    1993-11-01

    Recent results on photo- and hadroproduction of heavy flavor particles from fixed target experiments at CERN and Fermilab are presented. These include results on production characteristics, cross-section and pair correlation for both charm and beauty mesons.

  11. 29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Fire Protection Fixed Fire Suppression Equipment... employer shall sample the dry chemical supply of all but stored pressure systems at least annually...

  12. 16. PIER CAP DETAIL, SHOWING EXPANSION AND FIXED BEARING SHOES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. PIER CAP DETAIL, SHOWING EXPANSION AND FIXED BEARING SHOES, BOTTOM CHORD / END POST CONNECTION AND CANTILEVERED SIDEWALK. VIEW TO WEST. - Holbrook Bridge, Spanning Little Colorado River at AZ 77, Holbrook, Navajo County, AZ

  13. 6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY NORTH OF VERTICAL LIFT SPAN, LOOKING SOUTHEAST. - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

  14. 3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION SPAN AND PONTOON FLOATING SPAN - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

  15. 4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH THE NEXT UNIT TO THE RIGHT, AND FIRST UNIT OF PONTOON FLOATING SPAN. - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

  16. 2. DETAIL VIEW OF ON RIGHT FOREGROUND FIXED SPAN TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL VIEW OF ON RIGHT FOREGROUND FIXED SPAN TO TRANSITIONAL MOVEABLE SPAN TO FLOATING SPAN IN MIDDLEGROUND - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

  17. FIXED END OF MIDDLE SPAN. WESTERN SIDE SHOWING WELDING OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FIXED END OF MIDDLE SPAN. WESTERN SIDE SHOWING WELDING OF TOP PLATE ADDED TO STRENGTHEN THE BRIDGE. - Spile Bridge Road Bridge, Spanning Black Lake Outlie at Spile Bridge Road, Oswegatchie, St. Lawrence County, NY

  18. An Alternative to the Fixed Step Salary Schedule

    ERIC Educational Resources Information Center

    Bruno, James E.

    1970-01-01

    The focus of this study is the development of an effective alternative to fixed step salary approaches to salary evaluation in school districts. A prototype model was derived which considered nine factors in salary evaluation. (Author/MF)

  19. 46 CFR 95.05-10 - Fixed fire extinguishing systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... retained as long as they are maintained in good condition to the satisfaction of the Officer in Charge... barges with sleeping accommodations for more than 12 persons. (b) A fixed carbon dioxide or...

  20. 46 CFR 95.05-10 - Fixed fire extinguishing systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... retained as long as they are maintained in good condition to the satisfaction of the Officer in Charge... barges with sleeping accommodations for more than 12 persons. (b) A fixed carbon dioxide or...